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Hyperthyroid Hints

Below is a growing list of 590

scientific articles that deal directly or indirectly with feline hyperthyroidism.

The articles are sorted by date with the most recent at the top. A brief description of the article follows the title. To follow a link to the abstract page, click on the title. A link to the source of the article is available by clicking on the journal title on the individual abstract page.

2014/Jan
The Prevalence of Ocular Lesions Associated with Hypertension in a Population of Geriatric Cats in Auckland, New Zealand

Abstract AIMS: To provide an estimate of the prevalence of ocular lesions associated with hypertension in geriatric cats in Auckland, New Zealand and to evaluate the importance of examination of the ocular fundi of cats over eight years of age.

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2014/01
Thyroid Scintigraphy in Veterinary Medicine

Thyroid scintigraphy is performed in cats and dogs and has been used to a limited degree in other species such as the horse.

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2013/10
The Development of an Indirect CT Lymphography Protocol for Sentinel Lymph Node Detection in Head and Neck Cancer.

IntroductionlPurpose: Identifying lymph node metastases in patients with head and neck cancer provides important staging and prognostic information for making treatment decisions. Conventional CT allows identification of enlarged metastatic lymph nodes but is not sensitive to metastasis in normal-sized lymph nodes.

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2013/10
Evaluation of Thyroid to Background Ratios in Hyperthyroid Cats

IntroductionlPurpose: Thyroid scintigraphy has been used to diagnose, quantify and characterize disease, and predict treatment outcome in hyperthyroid cats.

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2013/10
A Survey of Management Strategies of the Hyperthyroid Cat in Uk General Practice

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2013/09
More Than Just T4: Diagnostic Testing for Hyperthyroidism in Cats

Clinical challenges: In older cats presenting with clinical features of hyperthyroidism, confirmation of a diagnosis of thyroid disease is usually straightforward. at his clinic.

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2013/09
Feline Ckd: Pathophysiology and Risk Factors--What Do We Know?

PRACTICAL RELEVANCE: Chronic kidney disease (CKD) is one of the most frequently encountered disorders in cats, having increased in prevalence in recent decades.

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2013/09
Amino Acid, Iodine, Selenium, and Coat Color Status among Hyperthyroid, Siamese, and Age-Matched Control Cats
BACKGROUND: Hyperthyroidism is common among older cats, but its pathogenesis remains poorly understood. Siamese and Himalayan cats have a reduced risk of hyperthyroidism compared with domestic short-hair cat breeds. A mechanism of risk reduction in pointed-coat breeds is unknown.

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2013/09
Amino Acid, Iodine, Selenium, and Coat Color Status among Hyperthyroid, Siamese, and Age-Matched Control Cats

BACKGROUND: Hyperthyroidism is common among older cats, but its pathogenesis remains poorly understood. Siamese and Himalayan cats have a reduced risk of hyperthyroidism compared with domestic short-hair cat breeds. A mechanism of risk reduction in pointed-coat breeds is unknown.

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2013/08
Iodine Concentration in Commercial Cat Foods from Three Regions of the USA, 2008-2009

Fluctuations in iodine concentration in food have been suggested as one risk factor for the development of feline hyperthyroidism, an epidemic disease first described in 1979.

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2013/08
Feline Focus: Diagnostic Testing for Feline Thyroid Disease: Hypothyroidism
Although naturally occurring hypothyroidism is very rare in cats, iatrogenic hypothyroidism is a recognized complication of treatment for hyperthyroidism.

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2013/08
Feline Focus: Diagnostic Testing for Feline Thyroid Disease: Hyperthyroidism

In older cats presenting with clinical features of hyperthyroidism, confirming the diagnosis of thyroid disease is usually straightforward.

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2013/08
Comparison between Computed Tomography and Tc- Pertechnetate Scintigraphy Characteristics of the Thyroid Gland in Cats with Hyperthyroidism

Scintigraphy is currently the reference standard for diagnosing feline hyperthyroidism; however, computed tomography (CT) is more widely available in veterinary practice.

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2013/07
Investigation of the Pathophysiological Mechanism for Altered Calcium Homeostasis in Hyperthyroid Cats
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OBJECTIVE: To investigate possible pathophysiological mechanisms (reduced plasma calcitriol concentrations and/or presence of concurrent or masked chronic kidney disease) for hypocalcaemiain hyperthyroid cats. METHODS: Prospective cohort study.

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2013/07
Investigation of the Pathophysiological Mechanism for Altered Calcium Homeostasis in Hyperthyroid Cats

OBJECTIVE: To investigate possible pathophysiological mechanisms (reduced plasma calcitriol concentrations and/or presence of concurrent or masked chronic kidney disease) for hypocalcaemiain hyperthyroid cats. METHODS: Prospective cohort study. Routine plasma biochemical parameters, plasma parathyroid hormone and calcitriol concentrations, ionized calcium concentrations, and venous pH, were measured at diagnosis and following treatment of hyperthyroidism.

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2013/07
Investigation of the Pathophysiological Mechanism for Altered Calcium Homeostasis in Hyperthyroid Cats

OBJECTIVE: To investigate possible pathophysiological mechanisms (reduced plasma calcitriol concentrations and/or presence of concurrent or masked chronic kidney disease) for hypocalcaemiain hyperthyroid cats.

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2013/06
Use of L-Thyroxine Supplementation after Radioiodine Therapy Helps Blunt the Worsening of Azotemia in Hyperthyroid Cats with Pre-Existing Kidney Disease

Hyperthyroidism develops in cats secondary to 1 or more autonomously functional thyroid adenomas. The progressive thy- rotoxicosis that ensues causes the chronic suppression of endoge- nous TSH release and ultimately the atrophy of normal thyroid tissue in these cats. This thyroid atrophy can lead to a period of transient hypothyroidism following curative radioiodine therapy. Once T4 values fall, circulating TSH levels increase, leading to reactivation of the previously suppressed and atrophied thyroid tissue in the large majority of these cats.

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2013/06
Investigation of the Pathophysiological Mechanism for Altered Calcium Homeostasis in Hyperthyroid Cats

Hyperthyroid cats are reported to have reduced blood ionised calcium concentrations (iCa) and elevated plasma parathyroid hormone (PTH) concentrations, however, the pathophysiological mechanism for these changes is unknown. Intestinal absorption of calcium is regulated by calcitriol, and reduced plasma calcitriol concentrations are reported in human Graves’ disease patients. Therefore, if hyperthyroidism was associated with calcitriol defi- ciency in cats, this could be the pathophysiological mechanism for hypocalcemia and elevated plasma PTH concentrations.

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2013/06
Investigation of the Pathophysiological Mechanism for Altered Calcium Homeostasis in Hyperthyroid Cats

Hyperthyroid cats are reported to have reduced blood ionised calcium concentrations (iCa) and elevated plasma parathyroid hormone (PTH) concentrations, however, the pathophysiological mechanism for these changes is unknown.

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2013/06
Changes in Systolic Blood Pressure over Time in Cats with Chronic Kidney Disease

The association between hypertension and feline chronic kid- ney disease (CKD) is well recognised and the prevalence of hypertension in CKD has been reported to be between 19.4% and 65%. The objectives of this study were to assess the preva- lence of hypertension in cats with CKD seen in a first opinion clinical setting and to investigate subsequent changes in systolic blood pressure (SBP) over time in cats that were initially normo- tensive.

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2013/06
An Online Survey to Determine Owner Experiences and Opinions on the Management of Their Hyperthyroid Cats Using Oral Anti-Thyroid Medications

Hyperthyroidism is the most common feline endocrinopathy. Treatment options comprise anti-thyroid medication, iodine-restricted diet, surgical thyroidectomy and radioiodine. One hundred and eleven owners of hyperthyroid cats completed a detailed survey asking about their experiences and views on the management of hyperthyroidism.
2013/05
Renin-Angiotensin-Aldosterone System Activity in Hyperthyroid Cats with and without Concurrent Hypertension

BACKGROUND: Hypertension is present in some hyperthyroid cats at diagnosis or can develop after treatment for hyperthyroidism. Activation of the renin-angiotensin-aldosterone system (RAAS) could be involved in the pathogenesis of hypertension. HYPOTHESIS: Hyperthyroid cats that develop hypertension before or after treatment for hyperthyroidism will have greater RAAS activation than normotensive cats. ANIMALS: Ninety-nine hyperthyroid cats. METHODS: Retrospective case-control study.

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2013/04
Sedation of Hyperthyroid Cats with Subcutaneous Administration of a Combination of Alfaxalone and Butorphanol

OBJECTIVE: To evaluate the sedative, respiratory and cardiovascular effects of subcutaneously administered alfaxalone and butorphanol in a group of hyperthyroid cats. DESIGN: A prospective, single-centre observational study. METHODS: Client-owned hyperthyroid cats (n = 20) were examined and sedated with alfaxalone (3 mg/kg) and butorphanol (0.2 mg/kg) administered subcutaneously. Sedation scores, heart rate, respiratory rate and blood pressure were measured at 15-min intervals during the 45-min observation period and compared with pre-sedation values.

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2013/03
Duration of T4 Suppression in Hyperthyroid Cats Treated Once and Twice Daily with Transdermal Methimazole

BACKGROUND: Transdermal methimazole is an acceptable alternative to oral treatment for hyperthyroid cats. There are, however, no studies evaluating the duration of T4 suppression after transdermal methimazole application. Such information would be valuable for therapeutic monitoring. OBJECTIVE: To assess variation in serum T4 concentration in hyperthyroid cats after once- and twice-daily transdermal methimazole administration. ANIMALS: Twenty client-owned cats with newly diagnosed hyperthyroidism. METHODS: Methimazole was formulated in a pluronic lecithin organogel-based vehicle and applied to the pinna of the inner ear at a starting dose of 2.5 mg/cat q12h (BID group, 10 cats) and 5 mg/cat q24h (SID group, 10 cats).

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2013/02
[Interrelation between the Degree of a Chronic Renal Insufficiency and/or Systemic Hypertension and Ocular Changes in Cats]

Objective: The aim of this study was to evaluate whether the degree of renal insufficiency and/or high blood pressure in cats with chronic renal insufficiency (CRI) is related to the degree of change in the fundus and whether there are differences in blood pressure between the different accompanying diseases.

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2013/02
Clinical Outcome in 19 Cats with Clinical and Magnetic Resonance Imaging Diagnosis of Ischaemic Myelopathy (2000-2011)

Previous publications on ischaemic myelopathy in cats are limited to single case reports and small case series..

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2013/01
Measurement of the Radioactivity in the Excreta of Cats Treated with Iodine-131 for Hyperthyroidism

When hyperthyroidism is treated with radioiodine, up to 75 per cent of the injected dose is excreted in the faeces and urine, which poses hazards to handlers. Three groups of hyperthyroid cats were treated with 120, 150 and 200 megabecquerel (MBq) of radioiodine, and samples of faeces and urine-soaked litter (USL) were collected over a 24-hour period, once a week, for four weeks.

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2012/12
Scintigraphic Thyroid Volume Calculation in Hyperthyroid Cats

A successful, euthyroid outcome after radioiodine therapy in hyperthyroid cats ranges from 83% to 95%. Thyroid volume has been reported as one of the factors influencing radioiodine therapy outcome in man and cats.

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2012/12
Evaluation of Four Methods Used to Measure Plasma Insulin-Like Growth Factor 1 Concentrations in Healthy Cats and Cats with Diabetes Mellitus or Other Diseases

Objective-To evaluate 4 methods used to measure plasma insulin-like growth factor (IGF) 1 concentrations in healthy cats and cats with diabetes mellitus or other diseases.

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2012/12
Circulating Natriuretic Peptide Concentrations in Hyperthyroid Cats

OBJECTIVES: To assess the influence of thyroid function on natriuretic peptide concentration in hyperthyroid cats before and after treatment.

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2012/11
Paraneoplastic Hypercalcemia
Paraneoplastic syndromes (PNSs) are neoplasm-associated alterations in bodily structure or function or both that occur distant to the tumor. They are an extremely diverse group of clinical aberrations that are associated with the noninvasive actions of the tumor. In many situations, the PNS parallels the underlying malignancy, and therefore, successful treatment of the tumor leads to disappearance of the PNS.

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2012/11
Hyperthyroidism in Cats: What's Causing This Epidemic of Thyroid Disease and Can We Prevent It?

PRACTICAL RELEVANCE: Since first being reported in the late 1970s, there has been a dramatic increase in the prevalence of hyperthyroidism in cats. It is now recognized worldwide as the most common feline endocrine disorder. PATIENT GROUP: Hyperthyroidism is an important cause of morbidity in cats older than 10 years of age. It is estimated that over 10% of all senior cats will develop the disorder. CLINICAL CHALLENGES: Despite its frequency, the underlying cause(s) of this common disease is/are not known, and no one has suggested a means to prevent the disorder.

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2012/10
Surprising Bloodwork Results Following Treatment of 90 Hyperthyroid Cats with Radioactive Iodine-131 (131i)

Introduction/Purpose: Radioactive Iodine-131 (131I) has long been used for the treatment of patients with hyperthyroidism. Little information is available pertaining to the outcome of such treatments in cats. In an effort to expand this knowledge, bloodwork was obtained at three weeks and three months following 131I treatment of hyperthyroidism in 90 cats.

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2012/10
Calcium and Phosphate Homeostasis in Hyperthyroid Cats - Associations with Development of Azotaemia and Survival Time
OBJECTIVES: To evaluate calcium and phosphate homeostasis in hyperthyroid cats and determine if plasma parathyroid hormone and fibroblast growth factor-23 are associated with the presence of -azotaemic chronic kidney disease and/or have prognostic significance. METHODS: Retrospective cohort study.

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2012/09
Thyroid Scintigraphy Findings in 1,572 Cats with Hyperthyroidism.

Thyroid scintigraphy provides valuable information regarding both thyroid anatomy and physiology and plays an integral role in the diagnosis, staging, and management of feline thyroid disease.

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2012/09
Nutritional Management of Feline Hyperthyroidism

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2012/09
Managing Hyperthyroidism in Cats

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2012/09
Hyperthyroid Summit: Therapy of Hyperthyroid Cats with Large Thyroid Masses
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Despite more than 30 years of investigation, and strong clinical suspicions of an environmental and/or dietary mechanism, the exact etiology of feline hyperthyroidism remains elusive.

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2012/09
Hyperthyroid Cats on Long-Term Medical Treatment Show a Progressive Increase in the Prevalence of Large Thyroid Tumors, Intrathoracic Thyroid Masses and Suspected Thyroid Carcinoma

Thyroid scintigraphy provides valuable information regarding both thyroid anatomy and physiology and plays an integral role in the diagnosis, staging, and management of feline thyroid disease.

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2012/08
Scintigraphic Thyroid Volume Calculation in Hyperthyroid Cats

A successful, euthyroid outcome after radioiodine therapy in hyperthyroid cats ranges from 83% to 95%. Thyroid volume has been reported as one of the factors influencing radioiodine therapy outcome in man and cats.
2012/08
Laparoscopic Adrenalectomy for Management of a Functional Adrenal Tumor in a Cat

CASE DESCRIPTION: A 9-year-old castrated male domestic shorthair cat was examined because of hypertension that persisted after resolution of the patient's hyperthyroidism. Bilateral hypertensive retinopathy, a systolic heart murmur, left ventricular hypertrophy, and tachycardia were present.

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2012/08
Knowns and Unknowns of Feline Hyperthyroidism

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2012/07
Thyroid Disorders in the Geriatric Veterinary Patient

The effects of age, concurrent illness, and administered medications complicate diagnosis of thyroid dysfunction in geriatric patients. Interpretation of thyroid hormone testing should take these factors into account.

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2012/07
Decabromobiphenyl, Polybrominated Diphenyl Ethers, and Brominated Phenolic Compounds in Serum of Cats Diagnosed with the Endocrine Disease Feline Hyperthyroidis
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The incidence of cats being diagnosed with feline hyperthyroidism (FH) has increased greatly since it was first described in 1979. The cause of FH has not been established. Hypothetically, there is a link between increasing FH and exposure to brominated flame retardants.

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2012/07
Clinical Pathology Interpretation in Geriatric Veterinary Patients

Routine monitoring of clinicopathologic data is a critical component in the management of older patients because blood and urine testing allows the veterinarian to monitor trends in laboratory parameters, which may be the early indicators of disease.

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2012/07
Arterial Thromboembolism: Risks, Realities and a Rational First-Line Approach

PRACTICAL RELEVANCE: Feline arterial thromboembolism (ATE) is a common but devastating complication of myocardial disease, often necessitating euthanasia. A combination of endothelial dysfunction and blood stasis in the left atrium leads to local platelet activation and thrombus formation. Embolisation of the thrombus results in severe ischaemia of the affected vascular bed. With the classic 'saddle thrombus' presentation of thrombus in the terminal aorta, the diagnosis can usually be made by physical examination.

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2012/05
Thyroid Scintigraphy Findings in 917 Cats with Hyperthyroidism

Thyroid scintigraphy provides valuable information regarding both thyroid anatomy and physiology and plays an integral role in the diagnosis, staging, and management of feline thyroid dis- ease. Recently, Harvey et al (Scintigraphic findings in 120 hyperthyroid cats. JFMS 2009;11: 96) reported that nearly 1 of 5 hyperthyroid cats had multiple areas of increased radionuclide uptake (IRU) visible on thyroid imaging, commonly with intra-thoracic tissue that could not be palpated.

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2012/05
Restoration of Euthyroidism in Medically Treated Hyperthyroid Cats with Iatrogenic Hypothyroidism (IH) Improves Renal Function.

IH is reported to increase the incidence of azotemia in hyperthyroid cats following treatment. IH is also associated with a decreased heart rate (HR), packed cell volume (PCV) and plasma alkaline phosphatase activity (ALP). Hypothyroidism reduces glomerular filtration rate (GFR) in other species, and treatment of hypothyroidism in dogs is reported to increase GFR.

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2012/05
Nuclear Imaging in Veterinary Endocrinology

Scintigraphic studies are used in veterinary medicine to image thyroid, parathyroid, adrenal and pancreatic diseases. By far, the most common of these studies is thyroid scintigraphy.

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2012/05
Effect of the Stage of Chronic Kidney Disease on Serum Total Thyroxine in Cats
Non-thyroidal illnesses, such as chronic kidney disease, are one of the factors that can affect total thyroxine and hinder the diagnosis of hyperthyroidism in cats. Cats with chronic kidney disease are currently staged according to the degree of azotemia based on the IRIS (International Renal Interest Society) guide- lines. The purpose of the present study was to determine the influence of chronic kidney disease stage on serum total thyroxine (TT4) in cats.

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2012/05
Antioxidant Status in Hyperthyroid Cats before and after Radioiodine Treatment
BACKGROUND: Reversible antioxidant depletion is found in hyperthyroid humans, and antioxidant depletion increases the risk of methimazole toxicosis in rats. OBJECTIVES: To determine whether abnormalities in concentrations of blood antioxidants or urinary isoprostanes were present in hyperthyroid cats, and were reversible after radioiodine treatment.

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2012/05
Amino Acid, Iodine, Selenium, and Coat Color Status among Hyperthyroid, Siamese, and Age-Matched Control Cats

Hyperthyroidism is common among older cats, but its patho- genesis remains poorly understood. Siamese and Himalayan cats have a reduced risk of hyperthyroidism than other cat breeds. Tyrosine is the amino acid precursor for thyroxine and melanin. Earlier studies reported tyrosine as a limiting amino acid in some cat foods resulting in poor coat melanin production in dark- coated cats.

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2012/04
Adrenal Function in Cats with Hyperthyroidism

Adrenal function may be altered in animals with hyperthyroidism. The aim of the study was to assess adrenal function of hyperthyroid cats (n = 17) compared to healthy cats (n = 18) and cats with chronic diseases (n = 18). Adrenal function was evaluated by adrenocorticotropic hormone (ACTH) stimulation test and the urinary cortisol to creatinine ratio (UCCR) was determined.

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2012/02
Ultrasonographic Measurements of Adrenal Glands in Cats with Hyperthyroidism

Feline hyperthyroidism is potentially associated with exaggerated responsiveness of the adrenal gland cortex. The adrenal glands of 23 hyperthyroid cats were examined ultrasonographically and compared to the adrenal glands of 30 control cats. Ten hyperthyroid cats had received antithyroid drugs until 2 weeks before sonography, the other 13 were untreated.

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2012/02
The Feline Thyroid Gland: A Model for Endocrine Disruption by Polybrominated Diphenyl Ethers (PBDES)?

The role of polybrominated diphenyl ethers (PBDE) was investigated in the occurrence of feline hyperthyroidism (FH) by evaluating 15 PBDE congeners in serum from 62 client-owned (21 euthyroid, 41 hyperthyroid) and 10 feral cats. Total serum PBDE concentrations in euthyroid cats were not significantly different from those of hyperthyroid cats. Total serum PBDE in feral cats were significantly lower than in either of the groups of client-owned cats.

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2012/02
Leptin Levels in Hyperthyroid Cats before and after Treatment

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2012/02
High Polybrominated Diphenyl Ether Levels in California House Cats: House Dust a Primary Source?

Polybrominated diphenyl ethers (PBDEs) are brominated flame retardants that act as endocrine disruptors, affecting thyroid hormone homeostasis. As a follow-up to a recent study showing high PBDE levels in household cats and linking PBDE levels with cat hyperthyroidism, we measured PBDEs, polychlorinated biphenyls (PCBs), and organochlorinated pesticides (OCPs) in serum samples from 26 California household cats (16 hyperthyroid, 10 controls) using liquid-liquid extraction and high-resolution gas chromatography/high-resolution mass spectrometry.

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2012
Radioiodine for Feline Hyperthyroidism

In Current Veterinary Therapy Xiv. Kirk R.W. and Bonagura J.D. Philadelphia, (2012).

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2011/12
Adverse Events in 50 Cats with Allergic Dermatitis Receiving Ciclosporin

Ciclosporin is an immunosuppressive drug that has been used to treat allergies and other immune-mediated diseases in cats, dogs and humans. Information about the adverse effects of ciclosporin in cats has been limited to smaller studies and case reports.

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2011/11
The Efficacy and Safety of a Novel Lipophilic Formulation of Methimazole for the Once Daily Transdermal Treatment of Cats with Hyperthyroidism

BACKGROUND: Previous studies on transdermal methimazole have used pluronic lecithin organogel as the vehicle. This might not be the most suitable vehicle for a lipophilic drug, such as methimazole. HYPOTHESIS/OBJECTIVES: Once daily transdermal administration of a novel lipophilic formulation of methimazole is as safe and effective as oral carbimazole in treating hyperthyroidism in cats. ANIMALS: Forty-five client-owned cats diagnosed with hyperthyroidism. METHODS: Prospective study. Cats with newly diagnosed, untreated hyperthyroidism were treated with carbimazole (5 mg p.o., q12h) or methimazole (10 mg) applied to the inner pinnae q24h.

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2011/11
The Efficacy and Safety of a Novel Lipophilic Formulation of Methimazole for the Once Daily Transdermal Treatment of Cats with Hyperthyroidism

BACKGROUND: Previous studies on transdermal methimazole have used pluronic lecithin organogel as the vehicle. This might not be the most suitable vehicle for a lipophilic drug, such as methimazole. HYPOTHESIS/OBJECTIVES: Once daily transdermal administration of a novel lipophilic formulation of methimazole is as safe and effective as oral carbimazole in treating hyperthyroidism in cats. ANIMALS: Forty-five client-owned cats diagnosed with hyperthyroidism. METHODS: Prospective study. Cats with newly diagnosed, untreated hyperthyroidism were treated with carbimazole (5 mg PO, q12h) or methimazole (10 mg) applied to the inner pinnae q24h.

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2011/10
Homeopathic and Integrative Treatment for Feline Hyperthyroidism--Four Cases (2006-2010)

Hyperthyroidism is a frequent veterinary problem, particularly in elderly cats. Homeopathic treatment and other integrative modalities were provided for four hyperthyroid cats whose owners did not want conventional treatment.

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2011/10
Cystic Ectopic Lingual Thyroid Tissue in a Male Cat

Case Description-A 6-year-old neutered male cat was examined because of a 4-week history of abnormal sounds while drinking and a previously noted mass at the base of the tongue. Clinical Findings-Oral examination revealed a 1-cm-diameter midline cystic mass on the dorsal aspect of the base of the tongue at the junction of the rostral two-thirds and caudal third of the tongue. Complete blood count and serum biochemical analysis revealed no clinically relevant abnormalities, and serum total thyroxine and free thyroxine (determined by equilibrium dialysis) concentrations were within the reference range.

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2011/09
Evaluation of Predictors for the Diagnosis of Hyperthyroidism in Cats

BACKGROUND: In humans, subclinical hyperthyroidism is diagnosed when serum thyroid hormone concentrations are within the reference range but thyroid stimulating hormone (TSH) concentration is subnormal. In a previous study, a higher prevalence of thyroid nodular disease was found in euthyroid geriatric cats with undetectable TSH (<0.03 ng/mL) compared to those with detectable TSH concentrations, suggesting subclinical hyperthyroidism might also exist in cats. HYPOTHESIS: Euthyroid cats with undetectable TSH concentrations have subclinical hyperthyroidism and may subsequently develop overt signs of hyperthyroidism.

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2011/09
Accuracy of Serum Free Thyroxine Concentrations Determined by a New Veterinary Chemiluminscent Immunoassay in Euthyroid and Hyperthyroid Cats

Free thyroxine (fT4) is the unbound biologically active fraction of total thyroxine (TT4). The pituitary-thyroid axis functions to maintain fT4 within a certain range and fT4 may reflect thyroid function more accurately than TT4. Several methodologies are currently available to measure the concentration of fT4 in serum.
The purpose of this study was to establish the reference interval in cats for a new analog veterinary fT4 immunoassay, IMMULITE® 2000 Veterinary Free T4 (VfT4), Siemens Healthcare Diagnostics Products Ltd., Llanberis, Gwynedd, UK and to compare the accuracy of VfT4 to the other fT4 assays currently available for evaluation of cats with clinical signs of hyperthyroidism.

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2011/07
Thyroid Hormone-Induced Haemoglobin Changes and Antioxidant Enzymes Response in Erythrocytes

Thyroid hormones modulate haemoglobin and reactive oxygen species (ROS) production, leading to antioxidant changes. This study evaluated the antioxidant response to ROS in erythrocytes in hypothyroid and hyperthyroid rats.

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2011/06
Treatment of Severe, Unresponsive, or Recurrent Hyperthroidism in Cats

Most hyperthyroid cats, at least in the early stages of their disease, can be readily controlled with antithyroid drugs. Similarly, most cats with mild to moderate hyperthyroidism are cured quite easily with standard “low” doses of radioiodine or by use of surgical thyroidectomy. Occasionally, the practicing veterinarian will see hyperthyroid cats that become unresponsive to antithyroid drug treatment, generally after months of satisfactory control.

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2011/06
Treatment of Hyperthyroidism and Concurrent Renal Disease: Is the "Tapazole Trial" Necessary?

Hyperthyroidism and chronic kidney disease (CKD) are both common disorders in older cats. Therefore, it should not be surprising that both disorders frequently develop together in the same cat. The prevalence of concurrent renal disease in cats with hyperthyroidism is estimated to be approximately 30-35%.

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2011/06
Titration of Dietary Iodine for Reducing Serum Thyroxine Concentrations in Newly Diagnosed Hyperthyroid Cats

The objective of this study was to determine the role of iodine restriction in the nutritional management of cats with naturally occurring hyperthyroidism. Five domestic shorthair cats ranging in age from 8–17 years were confirmed to have hyperthyroidism based on persistently increased serum total thyroxine concentrations (TT4), palpable thyroid nodule and weight loss. Serum TT4 concentrations ranged from 55- 146nmol/l (reference range 10–55nmol/l).

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2011/06
Titration of Dietary Iodine for Maintaining Normal Serum Thyroxine Concentrations in Hyperthyroid Cats

We have shown previously that restriction of dietary iodine (I) is a safe and effective method for decreasing serum thyroxine concentra- tions (TT4) in cats with hyperthyroidism. The objective of this study was to determine the maximum level of iodine in a nutritionally balanced feline mature adult food required to maintain normal serum TT4 concentrations in hyperthyroid cats currently being controlled on a food containing 0.15 ppm I (DMB) as measured by epiboron neutron atomic activation.

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2011/06
Outcome of Radioactive Iodine Therapy in Cats Receiving Recent Methimazole Therapy
Radioactive iodine (131I) is a widely used treatment for feline hyperthyroidism. Prior to 131I administration, many cats receive methimazole therapy. It has been suggested that recent withdrawal of methimazole prior to 131I may increase the risk of hypothyroid- ism, inhibit the response to therapy, or have no effect. To further address this question, a retrospective medical records search was performed to identify hyperthyroid cats that received 131I therapy after methimazole treatment.

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2011/06
Methimazole, Carbimazole & Alternative Medical Therapies for Feline Hyperthyroidism

The thioureylene class of antithyroid drugs, which includes methimazole and carbimazole, are most commonly used drugs for treatment of cats with hyperthyroidism. However a variety of other drugs are also available for medical treatment of hyperthyroid cats, some of which are not familiar to many practicing veterinarians.

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2011/06
Iris Stages of Chronic Kidney Disease before and after Treatment with Radioiodine in Cats with Hyperthyroidism

Although it is well established that concurrent chronic kidney disease (CKD) develops in about 30% of hyperthyroid cats, no one
has reported the use of the IRIS staging system for CKD before and after treatment of these hyperthyroid cats. The purpose of this study was to compare the effects of treatment in hyperthyroid cats with known stage 1 and 2 CKD in order to determine the effects of restoring euthyroidism or inducing hypothyroidism has on the IRIS stage in these cats.

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2011/06
Gene Expression Analysis of Feline Thyroid Tissue and Blood from Cats with Evidence of Mild or Marked Hyperthyroidism Reveals Potential Molecular Causes of the Disease and Identifies Future Routes for Intervention
Hyperthyroidism is a disorder resulting from the excessive production and secretion of T4 and T3 by the thyroid gland. Although the disorder and its pathological lesions have been well studied and described the cause remains illusive.

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2011/06
Efficacy of Iopanoic Acid for Treatment of Spontaneous Hyperthyroidism in Cats

Iopanoic acid is an iodine containing oral cholecystographic agent that has been used to treat hyperthyroidism in humans and has recently been evaluated in an experimental model of feline hyperthyroidism. The aim of this study was to evaluate the efficacy of iopanoic acid in cats with spontaneous hyperthyroidism.

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2011/06
Efficacy of Iopanoic Acid for Treatment of Spontaneous Hyperthyroidism in Cats

Iopanoic acid is an iodine containing oral cholecystographic agent that has been used to treat hyperthyroidism in humans and has recently been evaluated in an experimental model of feline hyperthyroidism.

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2011/06
Diagnostic Testing for Feline Hyper- and Hypothyroidism

The diagnosis of hyperthyroidism and hypothyroidism in cats is primarily based on a constellation of typical clinical features, including the cat’s signalment, history, clinical signs, and physical examination findings (eg, palpation of thyroid nodule).

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2011/06
Current Throughts on the Pathogenesis of Feline Hyperthyroidism

Hyperthyroidism is the most common endocrinopathy in cats, affecting a large percentage of middle to older aged cats in the U.S. Since its recognition as a clinical entity some 20 years ago, it has been diagnosed with increasing frequency; however, the pathogenesis of the disease is not currently understood. Recent studies into molecular, environmental, and nutritional causes of this disease have resulted in new thoughts regarding the pathogenesis.

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2011/06
Controlled Level of Dietary Iodine Normalizes Serum Total Thyroxine in Cats with Naturally Occuring Hyperthyroidism

Hyperthyroidism is a common disease in old cats. Excessive production of thyroid hormones is the hallmark of the disease. Three main treatments for feline hyperthyroidism include radioactive iodine, thyroidectomy, and antithyroid drugs such as methimazole. Previously we have shown that limiting dietary iodine to or below 0.27 ppm induces euthyroidism in cats with hyperthyroidism compared with a similar diet containing 0.42 ppm iodine. The objective of this study was to test whether dietary iodine at 0.32 ppm would induce euthyroidism in cats with naturally occurring hyperthyroidism.

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2011/06
Changes in Plasma Fibroblast Growth Factor-23 (Fgf-23) Concentrations after Treatment of Hyperthyroidism (Hth) in Cats with Variable Renal Function

FGF-23 is secreted by osteocytes and osteoblasts in response to hyperphosphatemia. FGF-23 enhances phosphaturia and is postu- lated to have a central role in the development of secondary renal hyperparathyroidism. Hyperthyroid cats have elevated plasma phosphate and parathyroid hormone concentrations, which may in part be associated with underlying chronic kidney disease (CKD). The aim of this study was to determine if plasma FGF-23 concentra- tions were associated with the presence of underlying CKD in hyperthyroid cats, and to investigate the changes in plasma FGF– 23 concentrations that occur following treatment of HTH.

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2011/05
When Normal Is Abnormal: Keys to Laboratory Diagnosis of Hidden Endocrine Disease

Although veterinary clinicians commonly rely on panels of laboratory tests with individual results flagged when abnormal, care should be taken in interpreting normal test results as well. There are several examples of this in evaluating patients with endocrine disease. The finding of a normal leukogram (absence of a stress leukogram) can be indicative of adrenal insufficiency in dogs, and this disorder can be especially elusive when there are no overt indicators of mineralocorticoid deficiency.

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2011/05
Congenital Hypothyroidism of Dogs and Cats: A Review

Congenital hypothyroidism is a rare and underdiagnosed congenital endocrine disorder in dogs and cats and the true incidence is unknown.

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2011/03
The Effect of Protease Inhibition on the Temporal Stability of Nt-Probnp in Feline Plasma at Room Temperature

OBJECTIVES: To evaluate whether the addition of a protease inhibitor (PI) to feline plasma improves the temporal stability of N-terminal pro-B-type natriuretic peptide (NT-proBNP). ANIMALS, MATERIALS AND METHODS: Forty-four EDTA blood samples were collected from 42 cats with cardiac disease or hyperthyroidism.

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2011/03
Feline Cerebrovascular Disease: Clinical and Histopathologic Findings in 16 Cats

Sixteen cats with cerebrovascular disease confirmed via histology to be of nontraumatic and nonneoplastic origins are described. In addition, the anatomy of the arterial supply of the cat's brain is reviewed. It is suggested that this unique arterial design may influence the incidence of cerebrovascular accidents in this species. Of the 16 cats reviewed, seven cats had ischemic infarctions, five had hemorrhagic infarctions, and four were diagnosed with intracranial hemorrhage. The median age was 8 yr and 9.5 yr in cats with infarctions and intracranial hemorrhages, respectively. Clinical signs were severe, acute, consistent with the localization of the cerebrovascular lesion, and influenced by underlying pathology.

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2011/03
Evaluation of Thyroid Functions with Respect to Iodine Status and Trh Test in Chronic Autoimmune Thyroiditis

Objective: Chronic autoimmune thyroiditis (CAT) is the most common form of thyroiditis in childhood and a frequent cause of acquired hypothyroidism. The objective of this study was to evaluate the thyroid status of childrenand adolescents with CAT with respect to iodine status and diagnostic values of thyrotropin-releasing hormone (TRH) test.

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2011/02
The Prevalence of Hypocobalaminaemia in Cats with Spontaneous Hyperthyroidism
OBJECTIVES: To determine the prevalence of hypocobalaminaemia in cats with moderate to severe hyperthyroidism and to investigate the relationship between cobalamin status and selected haematologic parameters. CLINICAL SIGNIFICANCE: This study indicates that a substantial proportion of cats with T(4) >/=100 nmol/L are hypocobalaminaemic and suggests that hyperthyroidism directly or indirectly affects cobalamin uptake, excretion or utilisation in this species.

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2011/02
Cognitive Dysfunction in Cats: Clinical Assessment and Management

Increasing numbers of cats are living to become elderly and they commonly develop behavioral changes. The objectives of this article are to consider the possible causes and prevalence of behavioral problems in pet cats, to describe how cognitive dysfunction syndrome (CDS) typically presents, and how its diagnosis and management are often complicated by the concurrent presence of multiple interacting disease processes.

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2011/01
Oxidative Stress Induced by Thyroid Dysfunction in Rat Erythrocytes and Heart

The aim of this study was to determine whether the effects of thyroid dysfunction induce oxidative stress in the blood and heart of male Wistar rats. Rats were randomly divided into three groups: group I served as control rats. Group II was treated daily with 0.05% benzythiouracile (BTU) administered in drinking water. Rats of group III have received l-thyroxine sodium salt (0.0012%), in drinking water.

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2011/01
Management of Hyperthyroidism in Client-Owned Cats with an Iodine-Restricted Food

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2011/01
Feline Systemic Hypertension: Diagnosis and Management
PRACTICAL RELEVANCE: the clinical importance of feline hypertension has been recognised for many years and most feline practitioners are quite familiar with this syndrome. Once systemic hypertension is identified, long-term management of the patient is needed to avoid catastrophic (eg, blindness due to retinal detachment) or subtle (eg, accelerated renal damage) target organ damage.

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2011/01
Feline Systemic Hypertension: Classification and Pathogenesis

PRACTICAL RELEVANCE: the increased availability of indirect blood pressure monitoring devices in clinical practice over the past decade has highlighted the significance of systemic hypertension in the feline population. Without routine monitoring and appropriate intervention, cats with undiagnosed systemic hypertension may first be presented with sudden-onset blindness as a consequence of either hyphaema or retinal detachment

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2010/12
Feline Thyroid Storm: Rapid Recognition to Improve Patient Survival
In human medicine, thyroid storm is a well-recognized condition of acute thyrotoxicosis in which the patient’s metabolic, thermoregulatory, and cardiovascular mechanisms are overwhelmed by excessive circulating levels of thyroid hormone.

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2010/11
Serum Concentrations of Methimazole in Cats after a Single Oral Dose of Controlled-Release Carbimazole or Sugar-Coated Methimazole (Thiamazole)
Methimazole (thiamazole) is an antithyroid drug commonly used to treat feline hyperthyroidism. It is routinely given twice daily. Carbimazole is a methimazole derivative that is rapidly metabolized to methimazole in vivo. A controlled-release tablet for once-daily carbimazole therapy has recently been developed in an attempt to improve compliance during medical management of feline hyperthyroidism.

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2010/11
Intrapericardial Ectopic Thyroid Carcinoma in a Cat
A 7-year-old spayed female domestic shorthair feline presented with tachycardia and was later euthanized due to a declining condition. On gross examination, the thoracic cavity contained an expansile, multiloculated mass that displaced the lungs dorsocaudally.

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2010/10
Homeopathic Prescribing for Chronic Conditions in Feline and Canine Veterinary Practice
INTRODUCTION: The peer-review literature contains no controlled clinical research of homeopathy in cats and very little in dogs. MAIN OBJECTIVE: To collect clinical outcomes data systematically from individualised homeopathic treatment of cats and dogs that would help to inform controlled research in feline and canine homeopathy. METHODS: Twenty-one homeopathic veterinary surgeons recorded data systematically from consecutive feline and canine patients over a 12-month period.

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2010/09
Feline Hyperthyroidism: Potential Relationship with Iodine Supplement Requirements of Commercial Cat Foods
ARTICLE RATIONALE: Since the late 1970s, there has been a significant increase in the prevalence of feline hyperthyroidism (FH). It is now recognized worldwide as the most common endocrinopathy of older cats, resembling toxic nodular goiter of older humans in iodine-deficient areas.

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2010/09
Calculation and Usage of the Thyroid to Background Ratio on the Pertechnetate Thyroid Scan

Feline hyperthyroidism is a common endocrine disorder. A single dose of 148 MBq (4 mCi) 131I is 95–98% effective for the treatment of hyperthyroidism in cats; however, the cause for treatment failures has not been determined.

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2010/08
The Feline Iodine Requirement Is Lower Than the 2006 NRC Recommended Allowance
Summary: The purpose of this study was to determine the iodine (I) requirement in adult cats. The I requirement estimate determined in our study at 12 months for adult cats (0.46 mg I/kg) was higher than current Association of American Feed Control Officials (AAFCO) recommendations (e.g. 0.35 mg I/kg), but was lower than the 2006 National Research Council (NRC) I recommended allowance (e.g. 1.4 mg I/kg).

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2010/08
Non-Invasive Measurement of Thyroid Hormone in Feces of a Diverse Array of Avian and Mammalian Species
These authors developed and validated a non-invasive thyroid hormone measure in feces of a diverse array of birds and mammals.

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2010/08
Multiple Endocrine Diseases in Cats: 15 Cases (1997-2008)
The objective of this retrospective study was to characterize a population of cats from a tertiary care center diagnosed with multiple endocrine disorders, including the specific disorders and time intervals between diagnosis of each disorder.

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2010/07
Survival and the Development of Azotemia after Treatment of Hyperthyroid Cats
Hyperthyroidism complicates the diagnosis of chronic kidney disease (CKD) as it increases glomerular filtration rate. Proteinuria and other clinical parameters measured at diagnosis of hyperthyroidism may be associated with the development of azotemia and survival time.
Conclusions and Clinical Importance: The proteinuria associated with hyperthyroidism is not a mediator of progression of CKD; however, it does correlate with all cause mortality.

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2010/07
Association of Iatrogenic Hypothyroidism with Azotemia and Reduced Survival Time in Cats Treated for Hyperthyroidism
Background: Iatrogenic hypothyroidism can occur after treatment of hyperthyroidism, and is correlated with a reduced glomerular filtration rate in humans and dogs. Hypothesis: Cats with iatrogenic hypothyroidism after treatment for hyperthyroidism will have a greater incidence of azotemia than euthyroid cats.

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2010/06
Thyroid Nodules, Bumps, & Lumps: When Is Medical Therapy a Useful Option?

Since hyperthyroidism was first reported 31 years ago, the prevalence of thyroidal nodules and the associated hyperthyroid state has been detected at an increasing frequency, with a prevalence now estimated to be as high as 2% of cats in general practice. Histopathology of affected thyroids usually reveals thyroid hyperplasia or benign thyroid adenoma (4); however, in a small percentage of cats (especially those with long-standing hyperthyroidism management with antithyroid drugs), thyroid adenocarcinoma is diagnosed (5). The time course of the progrand then to thyroid carcinoma is not known.

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2010/06
Investigation of Prognostic Factors for the Development of Renal Disease Following I-131 Therapy in Feline Hyperthyroidism
Hyperthyroidism is one of the most common endocrine disorders in middle aged to older cats. Renal disease may be masked by hyperthyroidism and subsequent I-131 therapy of hyperthyroid cats with subclinical renal dysfunction may precipitate progression to renal failure.

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2010/06
Iatrogenic Hypothyroidism (IH) Contributes to the Development of Azotemia in Hyperthyroid Cats.
Iatrogenic Hypothyroidism (IH) is reported to occur in some cats following treatment of hyper- thyroidism (HTH). Hypothyroidism reduces GFR in other species, therefore IH could contribute to the development of azotemia in hyperthyroid cats with underlying mild chronic kidney disease.

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2010/06
Evaluation of Activation of G Proteins in Response to Thyroid Stimulating Hormone in Thyroid Gland Cells from Euthyroid and Hyperthyroid Cats
OBJECTIVE: To evaluate alterations in ligand-stimulated activity of G proteins in thyroid gland cells of hyperthyroid cats. SAMPLE POPULATION: Membranes of thyroid gland cells isolated from 5 hyperthyroid cats and 3 age-matched euthyroid (control) cats immediately after the cats were euthanatized.

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2010/06
Congenital Hypothyroidism in a Kitten Resulting in Decreased Igf-I Concentration and Abnormal Liver Function Tests
A 7-month-old male kitten was presented with chronic constipation and retarded growth. Clinical examination revealed disproportional dwarfism with mild skeletal abnormalities and a palpable thyroid gland. The presumptive diagnosis of congenital hypothyroidism was confirmed by low serum total thyroxine (tT(4)) concentration prior to and after the administration of thyroid stimulation hormone (TSH), increased endogenous TSH concentration and abnormal thyroid scintigraphic scan.

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2010/06
Comparison of Models for Predicting Renal Disease Following I-131 Therapy for Feline Hyperthyroidism
Hyperthyroidism is a common endocrine disorder in middle aged to older cats. Therapy with I-131 is considered to be curative for > 90% of affected cats. However, the hyperthyroid state may mask underlying renal insuffciency and rates of subsequent renal disease following I-131 therapy approach 30%.

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2010/06
Circulating Natriuretic Peptides Concentrations in Hyperthroid Cats
The cardiac biomarkers N-terminal-pro-Brain Natriuretic Peptide (NT-pro-BNP) and N-terminal -pro-Atrial Natriuretic Peptide (NT-pro-ANP) have been shown to be of value in the diagnosis of heart disease and heart failure in cats. In humans, it is well known that natriuretic peptides are infuenced by factors other than pri- mary cardiovascular disease, including hyperthyroidism. The purpose of this study was to investigate natriuretic peptide concentrations in hyperthyroid cats before and after anti-thyroid treatment and to compare them to normal cats.

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2010/05
Pre- and Posttreatment Ultrasonography of the Thyroid Gland in Hyperthyroid Cats
Ultrasonography is useful for assessing the morphology of the thyroid gland in hyperthyroid cats. Our aim was to describe the ultrasonographic changes of the thyroid gland in hyperthyroid cats after 131I therapy.

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2010/03
The Effects of Iohexol Administration on Technetium Thyroid Scintigraphy in Normal Cats
Administration of iodinated contrast medium interferes with iodide uptake in the human thyroid gland and compromises diagnostic thyroid scintigraphy and radioiodine treatment for 4-6 weeks. However, the degree and duration of inhibition of thyroid uptake of pertechnetate (99mTcO4-) by iodinated contrast medium has not been established in any species.

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2010/02
Use of Thyroid Scintigraphy and Pituitary Immunohistochemistry in the Diagnosis of Spontaneous Hypothyroidism in a Mature Cat
A 12-year old, castrated male domestic shorthair cat presented with a 2-year history of poor hair coat, seborrhea, generalized pruritus and otitis externa. Low circulating concentrations of total serum thyroxine (TT(4)) and free thyroxine (fT(4)) and an elevated thyroid stimulating hormone concentration supported a diagnosis of primary hypothyroidism.

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2010/02
Thyroid Stimulation with Recombinant Human Thyrotropin in Healthy Cats, Cats with Non-Thyroidal Illness and in Cats with Low Serum Thyroxin and Azotaemia after Treatment of Hyperthyroidism

This study investigated the recombinant human thyrotropin (rhTSH) stimulation test in healthy cats (group 1), cats with non-thyroidal illness (group 2) and cats with low serum total T(4) (TT(4)) and azotaemia after (131)I treatment (group 3). Serum TT(4) responses and thyroidal pertechnetate uptake after administration of 25 microg rhTSH IV were assessed. Baseline serum TT(4) was significantly lower in group 3 compared with group 1, but not between other group pairs. Serum TT(4) increased significantly in groups 1 and 2 but not in group 3 after rhTSH administration.

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2010/01
Use of Thyroid Stimulating Hormone (TSH) in Cats

Thyroid stimulating hormone (TSH) measurement is routinely used for the diagnosis of thyroid disease in humans and dogs, but measurement of feline TSH is not routinely performed because a commercial feline TSH assay is not available. Research has been somewhat frustrated by the poor sensitivity of the canine TSH assay which is a long way from achieving the sensitivity seen in the newer generations of human TSH assays. However there are certain situations for which I believe the canine TSH assay has a useful role in the diagnosis of thyroid disease in cats, as long as the limitations of the assay are fully understood. Recent studies have used the DPC canine TSH assay for the measurement of feline TSH (1–4) in cats with occult hyperthyroidism.

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2009/10
Clinical Efficacy and Safety of a Once-Daily Formulation of Carbimazole in Cats with Hyperthyroidism
Evaluation of efficacy and safety of a novel controlled-release formulation of carbimazole in feline hyperthyroidism. A multicentre, self-controlled study in 44 client-owned cats with history and clinical signs of hyperthyroidism, and total thyroxine concentration greater than or equal to 50 nmol/l. Treatment was started at 15 mg once daily, response assessed after 10 days, and 3, 5, 8, 26 and 53 weeks and dose adjusted as required.

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2009/09
Retinol-Binding Protein in Serum and Urine of Hyperthyroid Cats before and after Treatment with Radioiodine
Retinol-binding protein (RBP) is suggested as a clinically useful marker of renal function in cats. The presence of urinary RBP in HT cats is a potential marker of tubular dysfunction that is correlated to thyroid status, although it is independent of circulating RBP concentrations. The decreased uRBP/c combined with the absence of changes in serum RBP after treatment suggests that the suspected tubular dysfunction was partly reversible with treatment of (131)I.

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2009/09
Pharmacokinetics of L-Thyroxine after Oral Administration to Healthy Cats

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2009/09
Optimal Testing for Thyroid Hormone Concentration after Treatment with Methimazole in Healthy and Hyperthyroid Cats
Methimazole suppresses thyroid hormone synthesis and is commonly used to treat feline hyperthyroidism. The degree of variation in thyroid hormone concentrations 24 hours after administration of methimazole and optimal time for blood sampling to monitor therapeutic efficacy have not been determined.

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2009/08
Risk Factors for Feline Hyperthyroidism in the UK
Previous studies of cats in the USA and New Zealand have identified a number of risk factors for the development of hyperthyroidism including feeding of canned cat food and being non-purebred. The objective of this study was to examine these and other risk factors in cats from London, UK.

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2009/08
Dermoid Cysts Presenting as Enlarged Thyroid Glands in a Cat
A 5-year-old spayed female cat was evaluated for hyperthyroidism based on an elevated free thyroxine (T(4)) measurement and bilaterally enlarged symmetric subcutaneous masses in the area of the thyroid glands.

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2009/08
Comparison of Plasma Clearance of Exogenous Creatinine, Exo-Iohexol, and Endo-Iohexol over a Range of Glomerular Filtration Rates Expected in Cats
The study investigated plasma clearance of exogenous creatinine (PECCT), exo-iohexol (PexICT) and endo-iohexol (PenICT) in six healthy cats, four cats with chronic kidney disease (CKD) and six hyperthyroid (HT) cats to assess potential differences in glomerular filtration rate (GFR) measurement over a wide range of GFR values.

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2009/07
Partial Characterization of Feline Myeloperoxidase and Investigation of Its Potential Role as an Autoantigen in Hyperthyroid Cats
OBJECTIVE: To partially characterize the cDNA, amino acid sequence, and tertiary structure of feline myeloperoxidase, describe its cellular location in mature granulocytes, and determine whether hyperthyroid cats have anti-myeloperoxidase antibody.

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2009/07
Effect of Thyroxine Supplementation on Glomerular Filtration Rate in Hypothyroid Dogs
BACKGROUND: Glomerular filtration rate (GFR) is decreased in humans with hypothyroidism, but information about kidney function in dogs with hypothyroidism is lacking. HYPOTHESIS: Hypothyroidism influences GFR in dogs.

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2009/06
Urinary Iodide Concentration in Hyperthyroid Cats
OBJECTIVE:To compare concentrations of urinary iodide (UI) in euthyroid and untreated hyperthyroid cats.

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2009/06
Letter to the Editor: Comparing Thyroid Palpation Techniques

I would like to compliment the authors in devising an objective comparison of the two thyroid palpation techniques. My only concern with the study is the experience factor. The authors state that each person had considerable experience palpating the thyroid gland of cats; however, my technique (T2) was introduced to them for the purpose of the study. It seems safe to assume that their experience with T2 was quite minimal compared with that of the classic technique (T1).

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2009/06
Interactions between thyroid and kidney function in pathological conditions of these organ systems: A review
Thyroidal status affects kidney function already in the embryonic stage. Thyroid hormones influence general tissue growth as well as tubular functions, electrolyte handling and neural input. Hyper- and hypo-functioning of the thyroid influences mature kidney function indirectly by affecting the cardiovascular system and the renal blood flow, and directly by affecting glomerular filtration, electrolyte pumps, the secretory and absorptive capacity of the tubuli, and the structure of the kidney.

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2009/06
Anticoagulant-Dependent in Vitro Hemagglutination in a Cat

A 17-year-old domestic shorthaired cat was presented to the Cornell University Hospital for Animals for recheck of hyperthyroidism previously treated with radioiodine. Marked agglutination was noted in a blood sample collected into EDTA for a CBC; no other clinical or hematologic evidence of hemolysis was observed and none developed despite persistent agglutination in additional EDTA samples collected over a 2-month period.

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2009/05
Hypertension in Hyperthyroid Cats: Prevalence, Incidence, and Predictors of Its Development

Hypertension and azotemic chronic kidney disease (aCKD) can be diagnosed concurrently with hyperthyroidism and have also been detected after initiation of treatment. The aims of this study were to estimate the prevalence of hypertension in cats at first diagnosis of hyperthyroidism, to estimate its incidence after treatment for hyperthyroidism and to identify predictors of the development of hypertension in hyperthyroid cats.

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2009/04
What Happened to the "Classic" Hyperthyroid Cat?
When hyperthyroidism was first reported In cats as a disease entity approximately 25 years ago, the majority of cases were advanced. The cats were thin, aggressive, polyuric, polydipsic, polyphaglc and had large palpable goiters. As cats have moved out of barns where they served as 'mousers' and Into peoples' homes as beloved family members, owners arc expecting veterinarians to provide excellent routine health care for their cats. You may now be confronted with the fat, happy cat that has only recently begun urinating more frequently in the litter box and has a trivial thyroid slip on physical examination. Yet this patient may be the ideal candidate for anti-hyperthyroid therapy such as I-131.

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2009/04
Thyroid enlargement and its relationship to clinicopathological parameters and T4 status in suspected hyperthyroid cats
To relate thyroid size to routine blood parameters and T4 status the ventral neck of 161 cats with clinical signs consistent with hyperthyroidism was examined by two independent observers using a semi-quantitative palpation system.

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2009/04
Thyroid dysfunction and kidney disease
Thyroid hormones (TH) are essential for an adequate growth and development of the kidney. Conversely, the kidney is not only an organ for metabolism and elimination of TH, but also a target organ of some of the iodothyronines' actions. Thyroid dysfunction causes remarkable changes in glomerular and tubular functions and electrolyte and water homeostasis.

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2009/04
Pulsed-Wave Doppler Tissue Imaging Velocities in Normal Geriatric Cats and Geriatric Cats with Primary or Systemic Diseases Linked to Specific Cardiomyopathies in Humans, and the Influence of Age and Heart Rate Upon These Velocities
Pulsed-wave Doppler tissue imaging (pw-DTI) techniques allow the non-invasive assessment of myocardial dynamics. pw-DTI has demonstrated regional and global diastolic impairment in various forms of human and feline cardiomyopathy. We hypothesise that in geriatric cats with systemic diseases that have been linked to specific cardiomyopathies in human beings, the myocardial velocity profile will be altered when compared to either normal or hypertrophic cardiomyopathy (HCM) cats; and that both age and heart rate have a significant affect upon pw-DTI velocities.

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2009/04
Effect of Recombinant Human Thyroid Stimulating Hormone on Serum Thyroxin and Thyroid Scintigraphy in Euthyroid Cats
This study investigated the thyroidal response to administration of recombinant human thyroid stimulating hormone (rhTSH) by means of serum total thyroxine (TT(4)) concentration and pertechnetate uptake by the thyroid gland in six healthy euthyroid spayed female cats.

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2009/03
Caudal mediastinal thyroglossal duct cyst in a cat
An eight-year-old domestic shorthair cat was evaluated because of dyspnoea secondary to pleural effusion. Ultrasound examination identified a large anechoic cyst-like structure in the caudal thorax. A median sternotomy was performed, and the cystic mass was removed. Microscopically, the excised tissue was identified as a multilocular thyroglossal duct cyst with ectopic thyroid tissue.
2009/02
Scintigraphic findings in 120 hyperthyroid cats
The aim of this study was to characterise the scintigraphic findings in a large population of hyperthyroid cats in order to determine the location of thyroid pathology in newly diagnosed hyperthyroid cats and those that had previously undergone thyroidectomy.

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2009/02
Feline thyroid carcinoma: diagnosis and response to high-dose radioactive iodine treatment
This study reports the scintigraphy, histopathology, sole treatment with high-dose radioactive iodine and outcome of eight cases of feline thyroid carcinoma.

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2009/02
Effects and Safety of Iopanoic Acid in Cats Administered Levothyroxine
The purpose of this study was to evaluate the safety and effect of iopanoic acid in 13 cats with hyperthyroidism induced by daily subcutaneous administration of 25microg/kg levothyroxine for a period of 42 days.

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2009/01
Short- and long-term follow-up of glomerular and tubular renal markers of kidney function in hyperthyroid cats after treatment with radioiodine
Hyperthyroidism can mask co-existing chronic kidney disease (CKD). Previous studies showed that post-treatment renal azotemia can be predicted by pre-treatment assessment of glomerular filtration rate (GFR). We hypothesized that treatment of hyperthyroidism may have different effects on glomerular and tubular function and these changes might be predicted by additional pre-treatment variables than GFR. Serum total T4 (TT4), creatinine and blood urea nitrogen (BUN), blood pressure (BP), body weight (BW), GFR, urine specific gravity (USG), urinary protein/creatinine ratio (UPC) and retinol binding protein/creatinine ratio (uRBP/c) were evaluated before and 1, 4, 12 and 24 weeks post-treatment with radioiodine ((131)I) in 21 non-azotemic hyperthyroid cats.
2009/01
Hyperthyroidism, a New Disease in Cats - Is It Caused by Exposure to Environmental Organic Pollutants?

Feline hyperthyroidism has been observed to increase all over the world since the end of 1970s. It has been suggested that increased risk of developing hyperthyroidism in cats is associated with indoor living and consumption of canned food.

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2009/01
Endocrine Diseases in Animals

BACKGROUND: Several endocrine disorders that affect humans also occur as endocrinopathies in companion animals. Spontaneous endocrine disorders in animals may provide valuable information for their counterparts in human endocrinology.

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2008/12
Comments regarding "Subclinical hyperthyroidism in cats: a spontaneous model of subclinical toxic nodular goiter in humans?"

We would like to comment on some of the points made by Wakeling et al. in their manuscript entitled ‘‘Subclinical Hyperthyroidism in Cats: A Spontaneous Model of SubclinicalToxic Nodular Goiter in Humans?’’ (1). The authors state: ‘‘The purpose of this study was to determine whether a relationship exists between TSH concentration and thyroid histopathology in biochemically euthyroid cats (as assessed by T4 [serum total T4 concentration] thereby providing further evidence for the existence of subclinical hyperthyroidism in cats.’

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2008/11
Congenital Thyroid Hypoplasia and Seizures in 2 Littermate Kittens

Two male littermate kittens (Kitten A and B) were examined at 14 weeks of age because of straining to defecate in the litter box. According to the owner neither kitten was seen having a bowel movement during the prior 2 weeks, but they were still eating, drinking, and urinating appropriately.

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2008/10
Prevalence of and risk factors for feline hyperthyroidism in Hong Kong
A study was conducted to determine the prevalence of and potential risk factors for feline hyperthyroidism in Hong Kong. Serum total thyroxine (T(4)) was measured in 305 cats aged 10 years and older that presented at various veterinary clinics in Hong Kong.

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2008/10
Interference of iohexol with radioiodine thyroid uptake in the hyperthyroid cat
Absorbed thyroid dose and effective half-life were determined in 46 hyperthyroid cats after treatment with a low dose (mean 111MBq) of radioiodine intravenously. Thirteen of these cats had received iohexol for glomerular filtration rate (GFR) measurement within 24h before treatment with radioiodine in view of another ongoing study at our institution.

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2008/09
Use of a Controlled-Release Formulation of Carbimazole for the Treatment of Feline Hyperthyroidism
Carbimazole and its active metabolite methimazole are the standard medical treatment for hyperthyroidism in cats. Most effective protocols are based on administration two or three times a day. A novel controlled-release formulation of carbimazole suitable for once daily administration was evaluated in cats newly diagnosed with hyperthyroidism in a multicentre, self-controlled study.

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2008/09
Evaluation of Urine Specific Gravity and Urine Sediment as Risk Factors for Urinary Tract Infections in Cats
BACKGROUND: It has been suggested that diseases that promote isosthenuria predispose to urinary tract infections because of a lack of the common bacteriostatic properties present in concentrated urine. OBJECTIVES: The purpose of this study was to assess the clinicopathologic risk factors for positive urine culture outcome in cats with chronic kidney disease (CKD), diabetes mellitus (DM), uncontrolled hyperthyroidism (HT), or lower urinary tract disease (LUTD). METHODS: For this retrospective study, medical records of all cats in which a urinalysis and aerobic bacterial urine culture were performed between January 1995 and December 2002 were reviewed.

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2008/07
Plasma clearance of exogenous creatinine, exo-iohexol, and endo-iohexol in hyperthyroid cats before and after treatment with radioiodine
BACKGROUND: Glomerular filtration rate (GFR) can be measured by clearance methods of different markers showing discrepancies and different reproducibility in healthy cats. Studies comparing different methods of GFR measurement in hyperthyroid cats have not yet been performed. HYPOTHESIS: Plasma clearance of exogenous creatinine (PECCT), exo-iohexol (PexICT), and endo-iohexol (PenICT) could lead to differences in GFR measurement and the need to use the same clearance method when comparing GFR before and after radioiodine treatment in hyperthyroid cats.

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2008/07
Diagnosis of hyperthyroidism in cats with mild chronic kidney disease
In cats with concurrent hyperthyroidism and non-thyroidal illnesses such as chronic kidney disease, total thyroxine concentrations are often within the laboratory reference range (19 to 55 nmol/l). The objective of the study was to determine total thyroxine, free thyroxine and/or thyroid-stimulating hormone concentrations in cats with mild chronic kidney disease.

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2008/06
Within- and between-examiner agreement for two thyroid palpation techniques in healthy and hyperthyroid cats
Thyroid gland palpation is an important aid for diagnosing feline hyperthyroidism in an early stage to prevent development of deleterious complications. Our objectives were to assess within- and between-examiner agreement for two thyroid gland palpation techniques in cats and to correlate palpation results with ultrasonographic thyroid measurements.

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2008/06
Recombinant Human Thyrotropin Administration Enhances Thyroid Uptake of Radioactive Iodine in Hyperthyroid Cats
Hyperthyroidism is the most diagnosed endocrine disorder in cats and radioiodine (131I) is the treatment of choice. The dose emission rate and radioactivity in urine, saliva, and on hair and paws are determined by the dose of administered 131I. A dose reduction of therapeutic 131I could possibly be achieved after recombinant human thyrotropin (rhTSH) administration as in humans with nodular goiter.

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2008/06
Methimazole-triggered lymphadenomegaly in a hyperthyroid cat?
In the March 2007 issue of JSAP, Niessen and others (2007) reported on a case of generalised lymphadenomegaly associated with methimazole treatment, in a hyperthyroid cat. The owner of the cat, which had been presented for routine vaccination, reported a 3-month history of intermittent vomiting and diar- rhoea, and possible polydipsia, polyphagia and concurrent weight loss. On physical examination, the presence of a small thyroid nodule was palpated. Total T4 and free T4 measurement con- firmed the diagnosis of hyperthyroidism, and methimazole was prescribed at a total dose of 5 mg twice daily. Within the next two weeks the cat became lethargic and anorectic, and suffered occasional vomiting and bilateral epiphora.

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2008/06
Efficacy of atenolol as a single antihypertensive agent in hyperthyroid cats
[beta]-Adrenergic blockers, particularly atenolol, are often recommended for the tachycardia and hypertension that accompany hyperthyroidism; however, the effects of monotherapy with atenolol on both systolic blood pressure (SBP) and heart rate (HR) have not been reported.

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2008/05
TSH Measurement in Senior Cats – a Prospective Study.
Hyperthyroidism is a common disease of older cats and is insid- ious in onset. In a retrospective study most hyperthyroid cats were found to have had undetectable TSH concentrations (o0.03 ng/ml) 1–3 years prior to diagnosis. Also, euthyroid cats with 0.03 ng/ml reportedly have a higher frequency of thyroid adeno- mas and/or hyperplastic nodules than cats with TSH ?0.03 ng/ml. The purpose of this prospective longitudinal study was to document the frequency with which hyperthyroidism is diagnosed in cats with differing TSH measurements.

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2008/05
RETINOL BINDING PROTEIN IN SERUM AND URINE OF HYPERTHYROID CATS BEFORE AND AFTER TREATMENT WITH RADIOIODINE.
Retinol binding protein (RBP) is a marker of renal tubular dam- age that is variably detected in urine of untreated hyperthyroid (HT) cats (van Hoek et al., JIM 2008;329:208–213). No data are available on serum RBP in cats or on the influence of treatment on serum or urinary RBP. In humans, serum RBP concentrations can be signifi- cantly lower in hyperthyroidism compared to eu- and hypothyroidism. The objectives of this study were to evaluate se- rum and urinary RBP levels in HT cats compared to healthy cats (H), and the influence hereon of radioiodine (131I) treatment.

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2008/05
PLASMA CLEARANCE OF EXOGENOUS CREATININE, EXO-IOHEXOL AND ENDO-IOHEXOL IN HEALTHY CATS, CATS WITH HYPERTHYROIDISM AND CATS WITH CHRONIC KIDNEY DISEASE.
Measurement of glomerular filtration rate (GFR) in cats allows detection of a decreased kidney function in an early stage of kidney disease. The plasma clearance of exogenous creatinine (PECCT) seems to be a promising alternative to the more complicated meth- ods for GFR measurement in cats. The objective of this study was to compare PECCT, exo-iohexol (Pex-ICT) and endo-iohexol (Pen- ICT) for discriminating healthy cats (H), hyperthyroid cats (HT) and cats with chronic kidney disease (CKD) suspected to have re- spectively normal, high and low GFR values.

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2008/05
N-acetyl-beta-D-glucosaminidase index as an early biomarker for chronic kidney disease in cats with hyperthyroidism
Hyperthyroid cats are at risk of developing azotemic chronic kidney disease (CKD) and diagnostic tools currently used to screen for CKD in hyperthyroid cats are either unreliable or impractical. Urine N-acetyl-03B2-d-glucosaminidase index (NAGi) is a good biomarker for azotemic CKD in hyperthyroid cats.

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2008/05
2008/04
An investigation of predictors of renal insufficiency following treatment of hyperthyroidism in cats

To determine if routine pre-treatment clinical data can be used to predict the development of overt renal insufficiency following treatment of feline hyperthyroidism, we studied retrospectively all non-azotemic cats undergoing treatment for hyperthyroidism at our hospital.

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2008/03
Pharmacokinetics of controlled-release carbimazole tablets support once daily dosing in cats
Carbimazole, a prodrug of methimazole, is used in the treatment of hyperthyroidism in cats. The pharmacokinetics of methimazole was investigated in healthy cats following oral administration of 15 mg of carbimazole as a controlled-release tablet (VidaltaÆ, Intervet).

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2008/03
Hyperthyroid Cats and Fire Retardants

In summary, the results of this study demonstrated high levels of PBDEs in cats and that fish-flavoured cat foods contained higher levels of PBDEs than other feeds. The level of PBDEs was not significantly higher in cats with hyper- thyroidism than the levels in the other groups of cats, although there was a lot of individual variation. Currently, there is no evidence that PBDEs are responsible for the rise in the incidence of hyper- thyroidism within the feline population. However, this study produced some inter- esting hypotheses, and this area warrants further investigation.

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2008/03
A Single Sample Method for Evaluating 51chromium-Ethylene Diaminic Tetraacetic Acid Clearance in Normal and Hyperthyroid Cats
BACKGROUND: Chronic kidney failure is frequently seen in middle-aged and elderly cats. 51Chromium-ethylene diaminic tetraacetic acid (51Cr-EDTA) clearance and single blood sample (SBS) method are used in several species to estimate the glomerular filtration rate (GFR).

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2008/02
[Treatment of feline hyperthyroidism with radioactive iodine-131]
Feline hyperthyroidism can be treated by thyroidectomy, antithyroid drugs, or radioactive iodine-131 (131I). The aim of this retrospective study was to evaluate the treatment of 83 hyperthyroid cats with 131I .

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2008/02
Hyperthyroid Cats and Fire Retardants

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2008/01
Immunoassay of urinary retinol binding protein as a putative renal marker in cats
The presence of low molecular weight retinol binding protein (RBP) in urine reflects tubular damage. Therefore, RBP has been used as a renal marker in humans and dogs. Using an anti-human RBP antibody (Ab), this study first demonstrates feline urinary RBP by Western blot analysis and then evaluates its potential as a renal marker in cats by enzyme-linked immunosorbent assay (ELISA).

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2007/12
Use of recombinant human thyroid-stimulating hormone for thyrotropin stimulation test in healthy, hypothyroid and euthyroid sick dogs
Recombinant human thyroid-stimulating hormone (rhTSH) was evaluated for the diagnosis of canine hypothyroidism, using TSH response tests.
2007/12
Subclinical hyperthyroidism in cats: a spontaneous model of subclinical toxic nodular goiter in humans?
Hyperthyroidism in cats, caused by nodular hyperplasia or adenomas, is clinically and histologically similar to toxic nodular goiter in humans. Subclinical hyperthyroidism in humans is defined as low thyrotropin (TSH) in conjunction with within-reference-range thyroid hormone concentrations, but has not previously been defined in cats.

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2007/11
Liver Function in Cats with Hyperthyroidism Before and After 131I Therapy
This study demonstrates that, regardless of a majority of cats with hyperthyroidism (15/19) having significant increases in at least one of their serum activity of liver derived enzymes, liver functional testing was not different between control and cats with hyperthyroidism. High serum liver enzyme activities were not associated with abnormalities in hepatic parenchyma and liver functional variables, regardless of the degree of increase. Serum liver enzyme activities return to normal after control of hyperthyroidism with 131I therapy. Cats with hyperthyroidism have a significantly higher serum fasting ammonia concentration than cats who were euthyroid. These results demonstrate that extensive examination for hepatobiliary disease in most cats with hyperthyroidism is unnecessary.

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2007/11
Changes in the glomerular filtration rate of 27 cats with hyperthyroidism after treatment with radioactive iodine
Hyperthyroidism is a common endocrinopathy of older cats and is associated with an increased glomerular filtration rate (gfr). Renal dysfunction is also common in older cats and may develop after they have been treated for hyperthyroidism. This paper describes the changes in the gfr of 27 hyperthyroid cats in the six months after their treatment with radioactive iodine ((131)I), and evaluates whether any commonly measured pretreatment parameters (serum biochemistry, systolic blood pressure, urine specific gravity) could predict a clinically significant decline in renal function.

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2007/09
Elevated PBDE levels in pet cats: sentinels for humans?
Co-incident with the introduction of polybrominated diphenyl ethers (PBDEs) into household materials nearly 30 years ago, feline hyperthyroidism (FH) has increased dramatically. Risk of developing FH is associated with indoor living and consumption of canned catfood. We hypothesized that increases in FH were, in part, related to increased PBDE exposure, with key routes of exposure being diet and ingestion of house dust.

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2007/08
Obesity Increases Free Thyroxine Proportionally to Nonesterified Fatty Acid Concentrations in Adult Neutered Female Cats
The obese cat is a model for the study of the progression toward type 2 diabetes. In this study, the impact of obesity on the hypothalamic-pituitary-thyroid axis was examined in 21 domestic shorthair cats before and after the development of obesity, which significantly increased body mass index (BMI), % body fat (BF), and girth (P<0.0001 for all). Serum total thyroxine (TT(4)), tri-iodothyronine, free T(4) (FT(4)) by direct dialysis, nonesterified fatty acids (NEFA), and leptin were measured, and FT(4) fraction (FFT(4)) was calculated.

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2007/07
Thyroid Tumors in Dogs and Cats
The clinical presentation and biologic behavior of thyroid tumors vary widely among dogs, cats, and human beings. Although thyroid tumors in dogs are rare, they are most likely to be malignant. Clinical signs are usually the result of impingement on surrounding structures, and clinical hyperthyroidism is rare. In contrast, hyperthyroidism resulting from benign thyroid proliferation is relatively common among older cats. Malignant tumors are extremely uncommon but have high metastatic potential. Irrespective of the tumor's ability to produce functional thyroid hormone, scintigraphy is often helpful in the diagnosis and staging of thyroid tumors in all three species. Treatment with surgery is a reasonable treatment option for noninvasive tumors. Iodine-131 is a well-established treatment for thyroid nodules in cats, but its effectiveness in dogs is controversial.

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2007/07
Thyroid Surgery in Dogs and Cats
Thyroid surgery is indicated for malignant and benign neoplasms or hyperplasia of the thyroid glands. A ventral midline cervical approach allows for bilateral thyroid exploration. Care should be taken to avoid the surrounding neurovascular structures and esophagus. Evaluation of both thyroids should be done before proceeding with partial or complete thyroidectomy. Complications of thyroid surgery include intraoperative hemorrhage and clinical signs associated with damage to the recurrent laryngeal nerves, parathyroid blood supply, or parathyroidectomy.

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2007/07
Testing for Hyperthyroidism in Cats
Hyperthyroidism remains a common endocrine disorder of cats. Although relatively easy to diagnose in classically presenting cats, the increased frequency of testing cats with early or mild disease has had significant implications for the diagnostic performance of many of the routine tests currently used. Further advances in the etiopathogenesis and earlier diagnosis are only likely with the advent of a species specific feline thyroid-stimulating hormone assay.

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2007/07
INVESTIGATION OF TWO METHODS FOR ASSESSING THYROID-LOBE ASYMMETRY DURING PERTECHNETATE SCINTIGRAPHY IN SUSPECTED HYPERTHYROID CATS
Our aim was to investigate thyroid:thyroid (T:T) ratio and visual inspection for assessing thyroid-lobe asymmetry in suspected hyperthyroid cats.

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2007/07
Feline Thyroid Storm
Thyroid storm is a syndrome described in human medicine to define a multisystemic disorder resulting from organ exposure to excessive levels of thyroid hormone. This form of acute thyrotoxicosis, although uncommon, can be life threatening and is a significant cause of mortality in human emergency rooms. Although thyroid storm is a well-recognized clinical entity in human medicine, it has not been described in veterinary medicine. This article discusses the human syndrome and defines a similar syndrome in hyperthyroid veterinary patients. The clinical signs of and treatment modalities for feline thyroid storm are also presented.

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2007/07
Etiopathologic findings of canine hypothyroidism
The causes of canine hypothyroidism are varied, but most cases result from irreversible acquired thyroid pathologic changes and only a small proportion arise from congenital anomalies of the thyroid gland or pituitary.

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2007/07
Etiopathologic Findings of Hyperthyroidism in Cats
None of the studies to date have isolated a single dominant factor that could be incriminated in the development of hyperthyroidism in cats. Rather, most of the studies provide further evidence of the widely held view that hyperthyroidism is a multifactorial disease in this species. At this time, the most likely candidates include one or more of the goitrogenic chemicals that have been shown to be present in cat food or the cat's environment. In addition, mutations of the thyroid stimulating hormone receptor gene or mutations of its associated G proteins seem to play an important role in the pathogenesis of this disease.

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2007/07
Clinical signs and concurrent diseases of hypothyroidism in dogs and cats.
Canine hypothyroidism may present with a wide range of clinical signs. The most common clinical signs are those of a decreased metabolic rate and dermatologic manifestations; however, many other clinical signs have been associated with hypothyroidism.

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2007/07
Cardiovascular and Renal Manifestations of Hyperthyroidism
In the simplest terms, hyperthyroidism is the clinical syndrome that results from an excess of thyroid hormones. This review considers the effects of hyperthyroidism on the cardiovascular and renal systems by reviewing the available literature on the clinical manifestations of this syndrome in the cat and also considering experimental studies and experience in other species, including human beings.

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2007/07
Calcium homeostasis in thyroid disease in dogs and cats
Hyperthyroidism is the most common endocrine disorder of cats, and hypothyroidism is the most common endocrine disorder of dogs. Little is known regarding the effects of hyperthyroidism, hypothyroidism, or treatment of these disorders on calcium metabolism in the dog or cat, however, especially any potential effects on bone.

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2007/07
Radioiodine is considered the treatment of choice for hyperthyroidism, but in some situations, methimazole therapy is preferred, such as in cats with preexisting renal insufficiency. Unfavorable outcomes from methimazole are usually attributable to side effects, such as gastrointestinal upset, facial excoriation, thrombocytopenia, neutropenia, or liver enzyme elevations. Because restoration of euthyroidism can lead to a drop in glomerular filtration rate, all cats treated with methimazole should be monitored with blood urea nitrogen and creatinine levels in addition to serum thyroxine (T4) and a complete blood cell count. Transdermal methimazole is associated with fewer gastrointestinal side effects and can be used in cats with simple vomiting or inappetence from oral methimazole. Hypertension may not resolve immediately when serum T4 is normalized, and moderate to severe hypertension should be treated concurrently with atenolol, amlodipine, or an angiotensin-converting enzyme inhibitor.

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2007/07
The indications, techniques, and expectations for radionuclide diagnostic studies on canine and feline thyroid glands are presented. In addition, the considerations surrounding radioiodine or external beam radiotherapy for benign and malignant thyroid disease are reviewed. The intent of this article is to familiarize primary care veterinarians with the utility of and outcome of the ionizing radiation-based diagnostic and therapeutic techniques for assessing and treating canine and feline thyroid disease.

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2007/06
Brominated-Flame Retardants (Bfrs) in Cats -- Possible Linkage to Feline Hyperthyroidism?
Coincident with global introduction of BFRs into household consumer products nearly 30 years ago, hyperthyroidism in cats has increased considerably. The etiopathogenesis of feline hyperthyroidism remains unknown. We hypothesized that increasing exposure of pet cats to BFRs such as the polybrominated diphenyl ethers (PBDEs) has, in some manner, contributed to the abrupt increase in and now common occurrence of feline hyperthyroidism. To begin to address this possibility, we assessed whether PBDE levels were detectable in serum from young (n= 5), older non-hyperthyroid (non-HT; n= 7), or hyperthyroid (HT; n= 11) cats.

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2007/06
Association of Urine Protein Excretion and Renal Function in Feline Hyperthyroidism
Hyperthyroidism is one of the most common endocrine disorder in middle aged to older cats. Renal insufficiency may be masked by the presence of hyperthyroidism and subsequent 1-131 therapy of hyperthyroid cats with abnormal renal function may precipitate renal failure. The purpose of this study was to investigate the potential association between renal protein excretion and glomerular filtration rate (GFR), as determined by nuclear scintigraphy, in detecting renal dysfunction in naturally occurring feline hyperthyroidism.

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2007/05
Canine thyroid carcinoma
Malignant thyroid carcinomas are relatively common in dogs. The majority of tumors are unilateral and nonfunctional. Before deciding on treatment options, it is important to determine whether the tumor is freely moveable or fixed and invasive into adjacent tissues.

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2007/04
Urinary Tract Infections in Cats with Hyperthyroidism, Diabetes Mellitus and Chronic Kidney Disease
The prevalence of urinary tract infections (UTIs) in cats with hyperthyroidism (n=90), diabetes mellitus (DM) (n=57) and chronic kidney disease (CKD) (n=77) was evaluated retrospectively. It was found to be 12% in cats with hyperthyroidism and DM, respectively, and 22% in cats with CKD.

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2007/03
Generalised Lymphadenomegaly Associated with Methimazole Treatment in a Hyperthyroid Cat
A nine-year-old, domestic shorthair cat was diagnosed with hyperthyroidism and treated with methimazole, which resulted in lethargy, inappetence and marked generalised lymphadenomegaly within two weeks of initiation of therapy.

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2007/01
What Is Your Diagnosis? Congenital Hypothyroidism
A 3-year-old neutered male domestic shorthair cat was referred for subtotal colectomy because of chronic con- stipation; the cat had had constipation since it was 6 weeks old. The cat had been treated with cisapride (1 mg, PO, q 12 h), lactulose (1 mL, PO, q 8 h), and canned pumpkin (amount and frequency not known) for 6 months prior to evaluation with no response. The decision to refer was based on an increase in the cat’s requirement of enemas (20 mL/kg [9 mL/lb] of tap water and petrolatum) from every 3 to 4 months to weekly.

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2007/01
Hypothyroidism and Myxedema Coma
Hypothyroidism is a common endocrinopathy in dogs but is rare in cats.
2006/12
Goiter in Apparently Euthyroid Cats

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2006/11
Within- and between-Examiner Repeatabilities for Two Thyroid Palpation Techniques in Cats
Hyperthyroidism frequently affects older cats. Early diagnosis and treatment prevents development of deleterious complications. Thyroid gland palpation is an important aid for diagnosing feline hyperthyroidism in an early stage. Aims of this study were first to define the repeatability within and between examiners for thyroid palpation by two palpation techniques, secondly to correlate the results of these two palpation techniques with ultrasonographic thyroid length measurements and finally to compare palpation scores before and after shaving.

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2006/11
Survival of Hyperthyroid Cats Is Not Affected by Post-Treatment Azotaemia

Treatment of feline hyperthyroidism (HTH) is frequently associated with the unmasking of chronic renal failure (CRF). It is generally assumed that cats that develop azotaemia following treatment for HTH have a worse prognosis than cats that do not, and this can affect treatment recommendations given to clients. The aim of the present study was to test this assumption.

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2006/11
Short- and Long-Term Follow-up of Hyperthyroid Cats Treated with Transdermal Methimazole
During the last years alternative treatment of hyperthyroid cats using transdermal methimazole has increasingly been used. However, so far only one study evaluated treatment response for up to 7 months and no data on daily T4 course after transdermal application are available. Objectives of the present study were to assess clinical response and T4 concentrations in hyperthyroid cats treated with transdermal methimazole during a follow-up period of up to 118 months, and to evaluate T4 course during a 10-hour period after methimazole application in selected cats.

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2006/11
Complications after Thyroidectomy in 101 Hyperthyroid Cats
The objective of this retrospective study was to describe the results of thyroidectomy in one hundred-and-one hyperthyroid cats, with emphasis on peri- and post-surgical complications and recurrence of hyperthyroidism.

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2006/11
Adenomatous Hyperplasia of the Thyroid Gland Is Related to TSH Concentration in Cats
Treatment of feline hyperthyroidism (HTH) is frequently associated with the unmasking of chronic renal failure (CRF). It is generally assumed that cats that develop azotaemia following treatment for HTH have a worse prognosis than cats that do not, and this can affect treatment recommenda- tions given to clients. The aim of the present study was to test this assumption.

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2006/10
Renal Function and Hyperthyroidism

Renal function Is profoundly Influenced by thyroid status. In humans and In rats, the effects of thyroid dysfunction on the kidneys are multiple and Include changes In renal blood flow (RBF), glomerular filtration rate (GFR), electrolyte pumps, tubular absorptive and secretory capacity, and kidney structure 4, 10. In cats, several studies have shown a marked decline of renal function after treatment of hyperthyroldism.1,2,S,6 This has been documented with all treatments routinely available for treatment of feline hyperthyroidism. The following text will give an overview of the physiological Interactions between thyroid hormones and renal function, and discuss related issues and clinical implications in hyperthyroid cats.

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2006/10
Homeopathic Treatment of Feline Hyperthyroidism

Hyperthyroidism is one of the most commonly diagnosed problems in cats. The most frequently used conventional treatments involve the use of methimazole or Iodine 131. The following study is a retrospective analysis of 13 cats diagnosed with hyperthyroidism that were treated by using one homeopathic remedy.

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2006/10
Feline Hyperthyroidism and Its Relation with Renal Function

Feline hyperthyroidism and chronic renal failure (CRF) are common diseases In older cats. Further, renal function is profoundly influenced by thyroid statos tn several species. In cats, several studies have shown a marked decline of renal function after treatment of hyperthyroidism. This has been documented with all treatments routinely available for treatment of feline hyperthyroidism.

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2006/09
Update on Drugs Used to Treat Endocrine Diseases in Small Animals
Drug therapy for the endocrine system is implemented to replace a hormone deficiency or to prevent or reduce the formation or effects of excess hormone.

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2006/09
MULTIMODALITY IMAGE FUSION TO FACILITATE ANATOMIC LOCALIZATION OF 99mTC-PERTECHNETATE UPTAKE IN THE FELINE HEAD
99mTc-pertechnetate is excreted in humans by the thyroid glands, gastric mucosa, salivary glands, choroid plexus, and sweat glands. Uptake attributed to the zygomatic and molar salivary glands is used commonly as a reference to assess thyroid uptake and differentiate euthyroid from hyperthyroid cats. However, the exact location and origin of uptake of 99mTc-pertechnetate in the head during thyroid scintigraphy in cats remains uncertain.

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2006/09
Identifying Removable Radioactivity on the Surface of Cats During the First Week after Treatment with Iodine 131
Because radioiodine (1-131) is excreted in urine and saliva, treated cats can accumulate I-131 on their coats from contacting soiled litter and grooming. This could result in removable radioactivity, which is a potential source of human exposure to radiation and specifically to internal contamination.

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2006/08
Sodium iodide I 131 treatment of dogs with nonresectable thyroid tumors: 39 cases (1990-2003)
OBJECTIVE: To determine outcome for dogs with nonresectable thyroid carcinomas treated with sodium iodide I 131 and identify factors associated with outcome.
2006/08
Effect of four sedative and anesthetic protocols on quantitative thyroid scintigraphy in euthyroid cats
OBJECTIVES: To determine the effect of sedation and anesthesia on thyroid and salivary gland uptake of technetium Tc 99m pertechnetate ((99m)TcO(4)) in euthyroid cats.
2006/07
[Transdermal carbimazole for the treatment of feline hyperthyroidism]
Orally administered antithyroid drugs are frequently used to treat hyperthyroidism in cats; however, the non-cooperative behaviour of some cats may make it difficult to administer tablets.

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2006/06
Thyroid Storm in Cats: Fact or Fiction
Thyroid storm is a syndrome described in human medicine to define a multi systemic disorder resulting from organ exposure to excessive levels of thyroid hormone. This form of acute thyrotoxicosis can be life-threatening and is a significant cause of mortality in human emergency rooms. Hyperthyroid cats that present with acute exacerbation of thyrotoxicosis may be described to have thyroid storm.

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2006/06
Aplastic anemia in cats - clinicopathological features and associated disease conditions 1996-2004
A retrospective study of 128 feline bone marrow reports identified 13 cases of aplastic anemia. Clinical diagnoses included chronic renal failure (n=5), feline leukemia virus infection (n=2), hyperthyroidism treated with methimazole (n=1) and idiopathic aplastic anemia (n=5).

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2006/05
Pediatric Endocrinology

Endocrine and metabolic disorders affecting puppies and kittens from birth until 6 months of age may manifest as clinical problems related to growth or to water metabolism (polydipsia and polyuria). Most commonly,endocrine and metabolic disorders affect growth of the animal,and puppies are often presented to the veterinarian for assessment of delayed or aberrant growth. Other endocrine disorders of small animals,such as juvenile-onset diabetes insipidus or diabetes mellitus, affect water metabolism, resulting in excessive thirst and urination and resultant difficulty in house-breaking.

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2006/05
Epidemiological Investigation of Feline Hyperthyroidism in a Urban Papulation in Germany

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2006/05
Does Subclinical Hyperthyroidism Exist in Cats?

Hyperthyroidism (HTH) in cats has strong parallels with toxic nodular goitre (TNG) in humans. A well-defined sub-clinical phase exists in TNG where thyroid hormone concentrations are within the reference range but thyroid stimulating hormone (TSH) concentration is sub-normal. The aim of this study was to determine if a sub-clinical phase of HTH could be identified in cats that were apparently euthyroid when first examined but that were subsequently diagnosed with HTH.

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2006/04
Results of thyroidectomy in 101 cats with hyperthyroidism
OBJECTIVE: To describe outcome after thyroidectomy in hyperthyroid cats, with emphasis on peri- and postsurgical complications and recurrence.

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2006/04
Evaluation of Ionized and Total Serum Magnesium Concentrations in Hyperthyroid Cats
Hyperthyroidism can increase the renal excretion of magnesium and thus cause hypomagnesemia in various species.

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2006/04
Clinical efficacy and safety of transdermal methimazole in the treatment of feline hyperthyroidism
Thirteen cats, newly diagnosed with hyperthyroidism, were treated with a transdermal formulation of methimazole at a dose of 5 mg (0.1 mL) (concentration of 50 mg/mL) applied to the internal ear pinna every 12 h for 28 d.

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2006/03
Use of Helical Computed Tomography for Measurement of Thyroid Glands in Clinically Normal Cats
OBJECTIVE: To determine the dimensions and volume of thyroid tissue in clinically normal cats by use of computed tomography.

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2006/03
Cloning and sequencing of feline thyrotropin (fTSH): heterodimeric and yoked constructs.
The genes encoding the mature common glycoprotein alpha (CGA) and hormone-specific beta subunits of feline thyroid stimulating hormone (fTSH) were cloned and sequenced.
2006/03
Accuracy of increased thyroid activity during pertechnetate scintigraphy by subcutaneous injection for diagnosing hyperthyroidism in cats
Our purpose was to determine the accuracy of increased thyroid activity for diagnosing hyperthyroidism in cats suspected of having that disease during pertechnetate scintigraphy using subcutaneous rather than intravenous radioisotope administration.

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2006/02
Thyroidectomy in the Cat
Thyroidectomy in cats is most commonly indicated to treat hyperthyroidism because of adenomatous hyperplasia of the thyroid glands. Preoperative stabilization of the hyperthyroid cat with antithyroid drugs is preferred to minimize anesthetic and surgical complications. Multiple surgical techniques for thyroidectomy have been reported, and results of surgery and complications differ between techniques.

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2006/02
Thyroid Scintigraphy in Hyperthyroidism.
Thyroid scintigraphy is a nuclear medicine procedure that produces a visual display of functional thyroid tissue based on the selective uptake of various radionuclides by thyroid tissue. Thyroid scintigraphy provides valuable information regarding both thyroid anatomy and physiology and can play an integral role in the diagnosis and management of cats with hyperthyroidism.

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2006/02
Survival times for cats with hyperthyroidism treated with iodine 131, methimazole, or both: 167 cases (1996–2003)
Conclusions and Clinical Relevance—Results suggest that age, preexisting renal disease, and treatment type were associated with survival time in cats undergoing medical treatment of hyperthyroidism. Median survival time for cats treated with methimazole alone was significantly shorter than median survival time for cats treated with I-131 alone or methimazole followed by I-131.

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2006/02
Radioiodine Treatment of Hyperthyroidism
Radioactive iodine provides a simple, effective, and safe treatment for cats with hyperthyroidism and is regarded by most authorities to be the treatment of choice.

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2006/02
Medical Management of Hyperthyroidism
Radioiodine is considered the treatment of choice for hyperthyroidism, but in some situations, methimazole therapy is preferred, such as in cats with pre-existing renal insufficiency.

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2006/02
Measurement of total thyroxine concentration in serum from dogs and cats by use of various methods
Total T4 concentrations determined in dogs and cats by use of 4 commonly used methods provided similar and consistent results.

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2006/02
Management guidelines for patients with thyroid nodules and differentiated thyroid cancer

THYROID NODULES are a common clinical problem. Epi- demiologic studies have shown the prevalence of palpa- ble thyroid nodules to be approximately 5% in women and 1% in men living in iodine-sufficient parts of the world (1,2). In contrast, high-resolution ultrasound can detect thyroid nodules in 19%–67% of randomly selected individuals with higher frequencies in women and the elderly (3).

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2006/02
Hyperthyroidism and the Kidney
Hyperthyroidism and chronic renal failure (CRF) are both common diseases of older cats. Hyperthyroidism increases GFR by a variety of physiologic effects. Chronic renal failure can suppress total T4 concentrations in cats with concurrent hyperthyroidism.

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2006/02
Diagnostic Tests for Hyperthyroidism in Cats
The diagnosis of hyperthyroidism, one of the most common disorders affecting elderly cats, is usually straightforward and considered routine by most practitioners. This paper reviews the available tests used to confirm a diagnosis of hyperthyroidism in cats and discusses their overall usefulness.

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2006/02
Diagnosis of Congenital and Adult-Onset Hypothyroidism in Cats
Whereas hyperthyroidism is the most common endocrine disorder in the cat, hypothyroidism is the least common feline endocrine disorder.

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2005/11
Thyroid to Salivary Ratios Determined by Technetium-99m Pertechnetate Imaging in Thirty-Two Euthyroid Cats

Thyroid to salivary (TS) ratio is the most commonly used scintigraphic parameter for differentiating euthyroid and hyperthyroid cats. Studies to determine the normal TS ratio have been performed in small cat populations. In this study, the TS ratio was determined in 32 cats between 8 and 13 years of age. The study population was documented to be euthyroid based on normal initial and 6-week follow-up serum thyroid concentrations and normal T3 suppression tests. All images were obtained with a low-energy all-purpose collimator between 20 and 40 min after the injection of approximately 111 MBq (3.0 mCi) pertechnetate. Manual regions of interest (ROI) were made of the thyroid and salivary glands of the ventral image A 95% prediction interval based on the natural log of the TS ratio was computed to provide a normal range of 0.48-1.66. This range is similar to previous studies, but suggests a slightly higher upper limit than previously reported.

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2005/11
Seroreactivity to A-type retrovirus proteins in a subset of cats with hyperthyroidism.
These results suggest that it may be possible to develop an animal (feline) model for the role of retroviruses in thyroid autoimmune diseases.

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2005/11
Relationship between selected echocardiographic variables before and after radioiodine treatment in 91 hyperthyroid cats.
Pretreatment T-4 assessment was not useful in determining which cats may have potentially relevant echocardiographic abnormalities, some echocardiographic abnormalities may emerge after treatment, and that less than 10% of the pre- or posttreatment abnormalities would be considered clinically relevant.

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2005/10
Feline Hyperthyroidism
This paper discusses the clinical signs, diagnosis and treatment of hyperthyroidism. now recognized as the most common endocrine disease of the cat. Although the aetiology of the disorder remains unclear, it diagnosis and treatment are by now routine. However, hyperthyroid cats are often less severely affected clinically than in the past because of increased awareness ad earlier diagnosis, and this can impact on the accuracy of diagnostic tests used and the need for more permanent treatment options.

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2005/10
Serum Troponin I Levels in Hyperthyroid Cats Before and After Treatment with Radioactive Iodine
These results suggest that chronic exposure to excess thyroid hormone may induce myocyte damage of sufficient severity to raise serum cTnI concentration in a proportion of cats that resolves following establishment of a euthyroid state.

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2005/09
Somatic mutations of the thyroid-stimulating hormone receptor gene in feline hyperthyroidism: parallels with human hyperthyroidism.
The identification of a potential genetic basis for feline hyperthyroidism is novel, increases our understanding of the pathogenesis of this significant feline disease, and confirms its similarity to TNG.

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2005/09
Feline hyperthyroidism. The contribution of nuclear medicine.
Radioiodine treatment is considered to be the easiest, the most effective and with fewer complications treatment for FH compared to thyreostatic drugs or surgical treatment. The contribution of nuclear medicine in FH is an interesting challenge for both veterinary and nuclear medicine.

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2005/09
Expression of inhibitory G proteins in adenomatous thyroid glands obtained from hyperthyroid cats.
A decrease in Gi2 expression decreases inhibition of adenylyl cyclase and allows a relative increase in stimulatory G protein expression. This results in increased amounts of cAMP and subsequent unregulated mitogenesis and hormone production in hyperthyroid cells. Decreased Gi2 expression may explain excessive growth and function of the thyroid gland in cats with hyperthyroidism.

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2005/09
Evidence for Differing Incidences of Feline Hyperthyroidism in London, Uk and Spain
There is much anecdotal evidence that the incidence of feline hyperthyroidism (HTH) varies hugely18279429 between different geographical locations. If this were true it could be used as a powerful tool, for comparative epidemiological studies looking at the exposure of cats in high and low incidence areas, to putative risk factors for the development of HTH. The purpose of this study was to test the hypothesis that the incidence of HTH in Spain is lower than that found in London, UK.

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2005/08
Pleural effusion with hyperthyroidism.
Generally, most ECG abnormalities resolve with successful management of thyrotoxicosis.

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2005/07
Thyroid Hormone Metabolism in the Brain of Domestic Animals
The action of thyroid hormones in the brain is strictly regulated, since these hormones play a crucial role in the development and in the physiological functioning of the central nervous system. It has been shown by many authors that brain tissue represents a special site of thyroid hormone handling. A relative independence of this tissue of the actual thyroid status was shown by our research group in birds and mammals.

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2005/07
Sedating and Anesthetizing Patients That Have Organ System Dysfunction
What agents and monitoring devices might be better in these patients? This anesthesiologist tells you how to handle common situations, such as: "Based on the results of physical examination and routine screening tests, what constitutes dysfunction of such severity to warrant a change in routine sedation or anesthetic protocols?"

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2005/07
Questions Incidence of Posttreatment Hypothyroidism in Cats

We belong to a schizophrenic profession. On one hand, we crave the status (not to mention the income) enjoyed by physicians. On the other hand, we shun the poten- tial liabilities associated with their practice. We want to practice “com- panion animal” medicine and surgery, but with the liability atten- dant to shoe repair. We print bumper stickers and put up bill- boards reminding people about “the other family doctor” and, in the next breath, insist that our patients have legal value only as property. By the latter lights, it seems strange that we never call our practices by names such as “Vinny’s Yellow Dog and Muffler Repair Shop.”

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2005/06
RELATIONSHIP BETWEEN SELECTED ECHOCARDIOGRAPHIC VARIABLES BEFORE AND AFTER RADIOIODINE TREATMENT IN 91 HYPERTHYROID CATS
Ninety-one spontaneously hyperthyroid cats were studied by two-dimensional and M-mode echocardiography with in a week before and 220133 months following oral radioiodine administration.

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2005/05
Update on thyroid function tests in cats: Where does TSH fit in?
An optimal feline TSH assay system would hopefully distinguish normal from low values. Such sensitivity will be critical as practitioners are already recognizing cats with palpable thyroid glands but normal total and free T4 concentrations. Also, the diagnostic difficulties associated with sick hyperthyroid cats would presumably be alleviated.

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2005/05
Thyroid disorders in the geriatric patient.
Thyroid disorders are common in older pets. They often present a diagnostic challenge, and reaching a definitive diagnosis can be difficult or impossible in some cases. It is important for the veterinary practitioner to be familiar with the historical, physical examination, and clinicopathologic data findings in each of these diseases and to become comfortable with the treatment, monitoring, and prognosis associated with thyroid diseases in geriatric pets.

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2005/05
The role of renin-angiotensin-aldosterone system (RAAS) in the development of systemic hypertension in cats treated for hyperthyroidism.
The cause for the development of hypertension in cats that are being treated for hyperthyroidism remains enigmatic. Activation of the RAAS tends to decrease with treatment both in cats that remain normotensive and those that develop hypertension. Although renal function declined significantly with treatment, cats in both NT (3/10) and HT (6/11) groups developed azotemia, and creatinine concentrations were not significantly different between the groups. The role of declining renal function in development of hypertension is worthy of further study.

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2005/05
Serum cobalamin and folate concentrations in cats with hyperthyroidism.
These findings suggest the presence of significant malabsorption of both cobalamin and folate in cats with hyperthyroidism, although hypermetabolism may lead to increased vitamin requirements. Hyperthyroidism may directly or indirectly lead to vitamin malabsorption, or some hyperthyroid cats may have concurrent small intestinal disease. Whatever the mechanism, concurrent intestinal dysfunction and vitamin deficiencies appear to be common in hyperthyroid cats.

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2005/05
G proteins show normal activation in response to thyroid stimulating hormone in feline hyperthyroid cells.
G protein activity is not altered in HT cells and a decreased expression of Gi protein and not an alteration in activity is part of the pathogenesis of feline hyperthyroidism.

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2005/05
Expression and purification of feline thyrotropin (fTSH): Immunological detection and bioactivity of heteridimeric and yoked glycoproteins.
This work constitutes the first report of in vitro expression and purification of recombinant feline thyrotropin. The demonstration of immunological recognition by antibodies generated against pituitary-source TSH, and of bioactivity confirms that the recombinant glycoprotein may be used to standardize and improve clinical assays for feline TSH.

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2005/05
Effects of methimazole on thyroid gland uptake of 99mTC-pertechnetate in 19 hyperthyroid cats.
Quantitatively, thyroid scintigraphy did not significantly change after methimazole treatment (P>0.1). Evaluation of serum TSH concentration may be helpful in identifying methimazole-induced changes in the scintigraphic features of hyperthyroidism in mildly hyperthyroid cats.

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2005/05
Cloning and sequencing of feline thyrotropin (fTSH): Heterodimeric and yoked constructs.
This work describes for the first time the full coding sequences of the two subunits of fTSH and has produced DNA constructs for its in vitro expression and purification.

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2005/05
Association of the risk of development of hypothyroidism after iodine 131 treatment with the pretreatment pattern of sodium pertechnetate Tc 99m uptake in the thyroid gland in cats with hyperthyroidism: 165 cases (1990-2002).
Cats with hyperthyroidism that have a bilateral scintigraphic pattern in the thyroid gland before 131I treatment appear to have a significantly higher risk of subsequently developing hypothyroidism, compared with cats with a unilateral scintigraphic pattern.

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2005/04
Secondary hypothyroidism following head trauma in a cat.
An 18-month-old female neutered domestic short hair cat was examined because of marked polydipsia and stunted growth following head trauma when it was 8 weeks old. A presumptive diagnosis of secondary hypothyroidism and central diabetes insipidus following head trauma was made.

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2005/02
Thyrotropin-stimulated DNA synthesis and thyroglobulin expression in normal and hyperthyroid feline thyrocytes in monolayer culture.
These data support the idea that feline hyperthyroidism is caused by cell abnormalities, resulting in dysregulated growth and hormone synthesis, and emphasize its importance as an animal model for Thyrotoxic Nodular Goiter.

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2005/02
Multivariate Analysis Of Risk Factors For Feline Hyperthyroidism In New Zealand
The results of this study support and extend those in several earlier reports and show that cats in New Zealand are, in many respects, similar to cats in Europe and North America in terms of their susceptibility to hyperthyroidism. The finding that female cats are predisposed to hyperthyroidism is at variance with most previously published work. It remains unclear which, if any, of the identified disease associations are causal, so further studies of this increasingly prevalent feline endocrinopathy are warranted.

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2005/02
Calcinosis involving multiple paws in a cat with chronic renal failure and in a cat with hyperthyroidism
Calcinosis of multiple paws is described in two cats. A metastatic pathogenesis was supported by the laboratory findings of hyperphosphataemia and a calcium x phosphorus solubility product > 7 g/L.

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2005/01
Feline endocrinopathies
Feline endocrinopathies (excluding diabetes mellitus) include hyperthyroidism, hypothyroidism, acromegaly, hyposomatotropism, diabetes insipidus, hyperadrenocorticism, primary sex hormone-secreting adrenal tumors, primary hyperaldosteronism, pheochromocytoma, hypoadrenocorticism, hyperparathyroidism, and hypoparathyroidism.

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2004/11
The options for treating feline hyperthyroidism.
The options for treating feline hyperthyroidism include surgery, medical therapy, and radioiodine therapy. The choice among these options is based on the animal's clinical status (the severity of clinical signs and the presence of concurrent nonthyroidal illness), the costs, the clinician's experience, and the availability of radioiodine therapy.

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2004/11
Examining the pathogenesis of feline hyperthyroidism.
No specific etiologies have been identified, but environmental and genetic factors have been studied to help explain the increase in the incidence of hyperthyroidism over the past few decades.

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2004/11
Choosing the best tests to diagnose feline hyperthyroidism.
Nonthyroidal illness can interfere with the diagnosis of hyperthyroidism, especially in cats with mild increases in total T4. Measuring free T4 by equilibrium dialysis and performing nuclear scintigraphy can enhance our ability to accurately diagnose this disorder in cats, including cats with concurrent nonthyroidal illness.

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2004/10
Environmental Risk Factors for Feline Hyperthyroidism: Pet Cats as Potential Sentinels for Public Health
Cats now live in approximately 34% of American households. With an average of two cats per home, this represents about 73 million cats that share the household environment with humans. Since it was first described in 1979, the incidence of clinical hyperthyroidism in cats has risen at an epidemic rate to become the most commonly diagnosed endocrine disease in older cats. The specific etiology is unknown, but it is most probably multifactorial in nature, involving host (age, gender, breed), environmental, and nutritional factors.

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2004/09
Transdermal methimazole treatment in cats with hyperthyroidism.
Although the overall efficacy of transdermal methimazole is not as high as that of oral methimazole at 2 weeks of treatment, it is associated with fewer GI adverse effects compared to the oral route.

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2004/09
Feline Hyperthyroidism (Thyrotoxicosis)

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2004/09
Efficacy and Safety of Transdermal Methimazole in the Treatment of Cats with Hyperthyroidism
The objective of this study was to determine whether transdermal methimazole was as safe and effective as oral methimazole for the control of hyperthyroidism in cats. Forty-seven cats with newly diagnosed hyperthyroidism were randomized to receive either transdermal methimazole in pluronic lecithin organogel (PLO; applied to the inner pinna), or oral methimazole (2.5 mg q12h for either route).

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2004/08
Traumatic partial hypopituitarism in a cat
Traumatic hypopituitarism was diagnosed in an 11-month-old male neutered cat. The presenting complaints were polydipsia, polyuria and lethargy of three months' duration.

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2004/08
Determination of Release Criteria for I-131 Therapy Cats

INTRODUCTION/PURPOSE: Radioactive iodine (I-131) therapy represents the current gold standard treatment option for feline hyperthyroidism. At present, release criteria for treated cats are non-uniform, poorly standardized, and largely extrapolated from experiences in treating humans with hyperthyroidism. At our institution, the duration of radiation isolation confinement has been determined by a < 2 mrem/hr (20uSv/hr) dose rate at patient surface resulting in an average total hospitalization period of 14 days.

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2004/07
The activity of the feline thyroglobulin promoter is compromised by flanking adenoviral sequence.
These results suggest cis acting elements in the flanking adenoviral sequences may compromise the activity of the feline thyroglobulin promoter and thus make Ad5 an unsuitable vector for transcriptionally targeted gene therapy in feline hyperthyroidism.

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2004/07
Review of Iodine Recommendations for Commercial Cat Foods and Potential Impacts of Proposed Changes (Abstract)

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2004/05

Surprised with feline hyperthyroidism study recommendation

I read with great interest the article by Edinboro et al (JAVMA, March 15, 2004, pp 879–886) describing an epidemiologic inves- tigation of feline hyperthyroidism. The main finding of the case-con- trol study was a higher risk for hyperthyroidism in cats that con- sumed canned foods (particularly from pop-top cans) versus non- canned foods. Can-lining plasticiz- ers (specifically bisphenol-A or derivatives) were implicated as pos- sible causative agents.

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2004/05
Management of hypertension in a geriatric cat
Hyperthyroidism and chronic renal disease occur commonly in geriatric cats, often in association with potentially life-threatening primary or secondary hypertension.

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2004/05
Hypertension In Dogs and Cats
The veterinary community has been slow to embrace the practice of routine screening for hypertension despite the realization that persistent elevations in blood pressure can have serious and even life-threatening consequences.

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2004/05
Effect Of Dietary Soy On Serum Thyroid Hormone Concentrations In Healthy Adult Cats
Short-term administration of dietary soy has a measurable although modest effect on thyroid hormone homeostasis in cats. Increase in T4 concentration relative to T3 concentration may result from inhibition of 5´-iodothyronine deiodinase or enhanced T3 clearance. Soy is a common dietary component that increases serum T4 concentration in cats.

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2004/04
Use of Endogenous Thyroid Stimulating Hormone Measurement to Diagnose Hyperthyroidism in Cats with Chronic Renal Failure
Hyperthyroidism can be difficult to diagnose in cats with renal disease since the total thyroxine (tT4) concentration is frequently within the laboratory reference range. This study investigated whether the measurement of thyroid stimulating hormone (TSH) could aid in diagnosing hyperthyroidism in cats with chronic renal failure (CRF).

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2004/03
High urinary corticoid/creatinine ratios in cats with hyperthyroidism.
The results of this study demonstrate that the urinary C : C ratio may be abnormally high in cats with hyperthyroidism, probably because of increased metabolic clearance of cortisol and activation of the pituitary-adrenocortical axis by disease. Although the clinical features of hyperthyroidism and hyperadrenocorticism in cats are different, hyperthyroidism should be ruled out when cats are suspected of hyperadrenocorticism on the basis of abnormally high urinary C : C ratios.

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2004/03
Epidemiologic Study Of Relationships Between Consumption Of Commercial Canned Food And Risk Of Hyperthyroidism In Cats
These findings suggest that the increasing prevalence of feline hyperthyroidism is not solely the result of aging of the cat population and that canned foods may play a role.Multivariate Analysis Of Risk Factors For Feline Hyperthyroidism In New Zealand.

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2004/03
Computed tomographic densitometry of normal feline thyroid glands.
Normal feline thyroid tissue is easily detected using CT without contrast medium enhancement. This information may be useful for CT evaluation of abnormal feline thyroid glands.

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2004/03
Accuracy of Elevated Thyroid: Salivary Ratio During Subcutaneous Thyroid Scintigraphy for Diagnosing Feline Hyperthyroidism

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2004/02
Treating Thyroid and Parathyroid Neoplasia in Dogs and Cats
Once a diagnosis of neoplasia of the thyroid gland is suspected or confirmed, a variety of treatments are available for dogs and cats. In this article, we first review the available therapeutic options for thyroid neoplasia in dogs and cats. We then describe therapy for parathyroid neoplasia, which is less common in both species.

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2004/02
Effects of Dietary Components on the Development of Hyperthyroidism in Cats
Hyperthyroidism was first reported in cats in 1979. Since that time, it has become the most common endocrinopathy in cats. Morphology of affected thyroid glands has been well characterized, but unfortunately the pathogenesis still remains a mystery. A number of factors have been postulated to play a role in pathogenesis, including heredity, genetics, breed, environment, and diet. These factors could affect any step in thyroid gland metabolism.

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2004/02
Blood Pressure Assessment in Healthy Cats and Cats with Hypertensive Retinopathy
OBJECTIVE: To determine whether there was an association between hypertensive retinopathy and high systolic, diastolic, and mean arterial blood pressures in cats. ANIMALS: 181 cats. CONCLUSIONS AND CLINICAL RELEVANCE: Hypertensive retinopathy was common in cats > or = 10 years of age and was associated with systolic blood pressures > 168 mm Hg when measured by the noninvasive oscillometric technique.

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2003/12
Percutaneous ultrasound-guided radiofrequency heat ablation for treatment of hyperthyroidism in cats
OBJECTIVE: To determine efficacy and safety of percutaneous radiofrequency heat ablation for treatment of hyperthyroidism in cats.

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2003/10
Relationship between orally administered dose, surface emission rate for gamma radiation, and urine radioactivity in radioiodine-treated hyperthyroid cats.
Surface emission rates for cats administered I131 appeared useful in determining upper limits (threshold) of urine radioactivity and are a valid method to assess the time at which cats can be discharged after I131 administration.

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2003/09
THE PREVALENCE OF HYPERTENSION IN HYPERTHYROID CATS AT DIAGNOSIS AND FOLLOWING TREATMENT.
Hyperthyroidism has been reported as an important cause of hypertension in the cat. However systematic studies of blood pressure in hyperthyroid cats have not been reported and, in large case series, signs consistent with hypertensive retinopathy/choroidopathy have been noted infrequently. The aim of this study was to determine the prevalence of hypertension in hyperthyroid cats at the time of diagnosis, and following initial treatment. In conclusion, severe hypertension is relatively uncommon in cats at the time of diagnosis of hyperthyroidism. However, a significant number of cats will develop hypertension following the induction of euthyroidism. It is, therefore, important to monitor cats’ blood pressure following initiation of therapy.

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2003/09
LONG-TERM CHANGES IN GLOMERULAR FILTRATION RATE IN HYPERTHYROID CATS FOLLOWING TREATMENT WITH IODINE-131.
It is generally believed that there is a decline in renal function following treatment of hyperthyroidism in cats, but no long-term assessment of glomerular filtration rate (GFR) has been performed. Our aim was to assess the effect of iodine-131 treatment on immediate and long-term renal function in cats with hyperthyroidism. In conclusion, most hyperthyroid cats treated with iodine-131 showed a significant decline in GFR within one month following treatment, however, this decline did not continue. Results also indicated that a subnormal TT4 may contribute to this reduction in GFR as normalisation of TT4 resulted in marked increase in GFR. Therefore, a dose of iodine-131 should be used, which does not render TT4 below the normal reference range. If the same is true for medical or surgical management of feline hyperthyroidism needs to be assessed.

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2003/09
Effect of measurement method on blood pressure findings in cats before and after therapy for hyperthyroidism.
We conclude that the method of measurement may affect BP results in hyperthyroid cats and that within the Doppler method, BP values obtained in a controlled environment by a trained operator are significantly lower than values obtained in a less controlled situation. Blood pressure methodologies used in this small study did not detect a significant change in BP in response to therapy for hyperthyroidism.

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2003/07
Cystic thyroid and parathyroid lesions in cats
Reports of cystic thyroid and parathyroid masses in cats are uncommon. Herein, the authors describe a series of four cats with cystic ventral cervical lesions, among them thyroid cyst (n=1), thyroid cystadenoma (n=2), and parathyroid adenocarcinoma (n=1).

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2003/07
Cystic Thyroid and Parathyroid Lesions in Cats

Reports of cystic thyroid and parathyroid masses in cats are uncommon. Herein, the authors describe a series of four cats with cystic ventral cervical lesions, among them thyroid cyst (n=1), thyroid cystadenoma (n=2), and parathyroid adenocarcinoma (n=1). Presentations ranged from completely asymptomatic cervical swellings to signs related to local compression of adjacent structures (e.g., trachea). Ultrasonographic evaluation was helpful in localization of the mass in two cases. Hormone analysis and concentration of cystic fluid were performed in one cat. Surgical excision was performed successfully in three cases. Histopathological examination was performed in all four cases. Long-term prognosis was excellent for those cases in which follow-up was available.
2003/05
Total thyroxine testing: Comparison of an in-house test kit with radioimmuno- and chemiluminescent assays.
Excellent concordance between Snap T4 results and either RIA or Immulite results was observed. All of these technologies can be used to accurately measure serum TT4 concentrations, but because of slight test-associated biases, the most consistent results will be obtained by using 1 test method exclusively.

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2003/05
RELATION OF SURVIVAL TIME AND URINARY PROTEIN EXCRETION IN CATS WITH RENAL FAILURE AND/OR HYPERTENSION.
Proteinuria is related to survival time in humans with renal failure. The aim of this study was to investigate the relationship of proteinuria to survival time in cats with variable renal function, and with or without systemic hypertension. Proteinuria predicts reduced survival times in cats with CRF. Further studies are now warranted to determine whether interventions that decrease proteinuria, such as treatment with ACE-inhibitors, will improve survival of cats with renal failure.

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2003/05
Diagnosis of feline hyperthyroidism using thyroid scintigraphy.
This study demonstrates that a palpable thyroid nodule is suggestive of feline hyperthyroidism despite normal serum thyroxine levels. In these cats additional diagnostics such as thyroid scintigraphy or measurement of fT4(ED) is recommended for the diagnosis of hyperthyroidism.

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2003/05
Clinical efficacy of transdermal methimazole in cats with hyperthyroidism.
The results of this study indicate that transdermal methimazole in PLO gel results in comparable efficacy by 4 weeks of treatment, with fewer GI side effects, compared to the same dose administered orally, and is therefore is a viable alternative in the treatment of feline hyperthyroidism.

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2003/04
Transdermal methimazole treatment in cats with hyperthyroidism
The objectives of this study were to assess serum thyroxine concentrations and clinical response in hyperthyroid cats to treatment with transdermal methimazole, and to determine if further investigation is indicated.

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2003/04
Evaluation of relationships between pretreatment patient variables and duration of isolation for radioiodine-treated hyperthyroid cats.
A pretreatment estimate for duration of isolation could be determined only from an equation based on the orally administered dose of 131I. These findings suggest that administration of the lowest efficacious dose possible is the dominant factor in reduction of duration of isolation for cats treated with 131I.

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2003/04
Efficacy and safety of once versus twice daily administration of methimazole in cats with hyperthyroidism.
Results suggest that once daily administration of methimazole was not as effective as twice daily administration in cats with hyperthyroidism and cannot be recommended for routine use.

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2003/04
Efficacy and Safety of Once Versus Twice Daily Administration of Methimazole in Cats with Hyperthyroidism

OBJECTIVE: To determine whether once daily administration of methimazole was as effective and safe as twice daily administration in cats with hyperthyroidism. DESIGN: Randomized, nonblinded, clinical trial. ANIMALS: 40 cats with newly diagnosed hyperthyroidism. PROCEDURE: Cats were randomly assigned to receive 5 mg of methimazole, PO, once daily (n = 25) or 2.5 mg of methimazole, PO, twice daily (15). A complete physical examination, including measurement of body weight; CBC; serum biochemical analyses, including measurement of serum thyroxine concentration; and urinalysis were performed, and blood pressure was measured before and 2 and 4 weeks after initiation of treatment.

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2003/02
Use of recombinant human thyroid-stimulating hormone for thyrotropin-stimulation testing of euthyroid cats.
The TSH stimulation test can be performed in cats by IV administration of 0.025 to 0.200 mg of rhTSH and measurement of serum TT4 concentrations at time of injection and 6 or 8 hours later. Clinical validation of the TSH stimulation test would facilitate development of additional tests of thyroid gland function, such as a TSH assay.

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2003/01
Spontaneous Feline Hypertension: Clinical and Echocardiographic Abnormalities, and Survival Rate

Systemic hypertension was diagnosed in 58 of 188 untreated cats referred for evaluation of suspected hypertension-associated ocular, neurologic. cardiorespiratory, and urinary disease, or diseases frequently associated with hypertension (hyperthyroidism and chronic renal failure).

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2003/01
Juvenile hyperthyroidism in a cat.
The cat was diagnosed with hyperthyroidism, and a unilateral thyroidectomy was performed followed by radioactive iodine at a later date. The clinical signs resolved following radioactive iodine, and the cat subsequently developed clinical hypothyroidism.

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2003/01
Arterial Thromboembolism in Cats: Acute Crisis in 127 Cases (1992-2001) and Long-Term Management with Low-Dose Aspirin in 24 Cases
Records of 127 cats with arterial thromboembolism (ATE) were reviewed. Abyssinian, Birman, Ragdoll, and male cats were overrepresented. Tachypnea (91%), hypothermia (66%), and absent limb motor function (66%) were common. Of 90 cats with diagnostics performed, underlying diseases were hyperthyroidism (12), cardiomyopathy (dilated [8], unclassified [33], hypertrophic obstructive [5], hypertrophic [19]), neoplasia (6), other (4), and none (3).

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2002/12

Radioiodine treatment of feline hyperthyroidism in Germany
AIM: Establishment of radioiodine treatment of feline hyperthyroidism in veterinary routine in accordance with German radiation protection regulations. PATIENTS AND METHODS: 35 cats with proven hyperthyroidism were treated with 131I in a special ward. Thyroid uptake and effective halflife were determined using gammacamera dosimetry. Patients were released when measured whole body activity was below the limit defined in the German "Strahlenschutzverordnung".

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2002/11
Predictors of response to radioiodine therapy in hyperthyroid cats.
There was a significant relationship between pretreatment thyroxine values and post-treatment thyroxine values at all of the follow-up time points (p < 0.001). There was also a relationship between thyroid to salivary gland technetium scan ratio results and serum thyroxine values at pretreatment and at 1 week post-treatment (p = 0.02, 0.005, respectively). A greater scan ratio was associated with higher thyroxine levels at these time points, but not at 1, 3, 6 or 12 months post-therapy.

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2002/09
Urinary Corticoid/Creatinine Ratios in Cats with Hyperthyroidism
Elevated urinary corticoid/creatinine (C/C) ratios in cats with signs and symptoms compatible with hyperadrenocorticism have been reported to be indicative of hyperadrenocortism. However, in addition to stress, diseases other than hyperadrenocorticism may also result in elevated urinary C/C ratios. Because many of the signs and symptoms of feline hyperadrenocorticism may also be found in cats with hyperthyroidism, the purpose of this study was to determine whether cats with hyperthyroidism may also have elevated urinary C/C ratios.

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2002/09
Serum TSH in Hyperthyroid Cats Pre- and Post Therapy
Feline hyperthyroidism can be difficult to diagnose. Sensitive TSH assays are used to diagnose this condition in humans. The aim of this study was to assess if serum TSH could distinguish between normal and hyperthyroid cats and determine if therapy normalizes TSH levels.

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2002/09
Relationship between Semi-Quantitative Thyroid Palpation and Total Thyroxine Concentration in Cats with and without Hyperthyroidism
In 155 cats, both with and without clinical signs of hyperthyroidism, total thyroxine (TT4) concentrations were compared to a sensitive, semi-quantitative thyroid palpation technique.

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2002/09
Pathogenesis of feline hyperthyroidism

Hyperthyroidism is recognised not only as the commonest endocrine disease of domestic cats but as one of the most frequently diagnosed disorders in small animal practice. Prior to its first definitive diagnosis in 1979, there were few reports of pathological abnormalities in feline thyroid glands and only anecdotal reference to clinical signs that may have been caused by hyperthyroidism. Since that time, there has been a marked increase in the frequency of diagnosis of feline hyperthyroidism.

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2002/09
Palpable Thyroid and Parathyroid Nodules in Asymptomatic Cats
Client-owned cats underwent surgery to remove palpable cervical masses in cats with normal total T4 values and no clinical signs of hyperthyroidism, renal disease, or hyperparathyroidism.

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2002/09
Evaluation of Free Thyroxine Measurement for the Diagnosis of Hyperthyroidism in Cats with Chronic Renal Failure
Diagnosis of hyperthyroidism in cats with chronic renal failure (CRF) can be problematic, as many cats will have normal total thyroxine (TT4) due to sick euthyroid syndrome. Free thyroxine (ff4) may be more sensitive in detecting cats with hyperthyroidism in the face of concurrent illness, however previous studies have identified frequent false positive test results. The purpose of this study was to evaluate IT4 as a test for hyperthyroidism in cats with CRF.
2002/09
Cats with Hyperthyroidism

Unlike most clinical academics, I have the opportunity of seeing a reasonable number of first opinion cases, as well as feline referrals. This gives me the opportunity of having regular clients and following their cats over the course of their natural lifespan - watching them grow from kittens into young adults, through middle age and subsequently into their geriatric years.

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2002/07
Quantitative thyroid scintigraphy as a predictor of serum thyroxin concentration in normal and hyperthyroid cats
Quantitative thyroid scintigraphy using pertechnetate was performed in 43 cats with various T4 concentrations and compared to eight normal control cats.

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2002/07
Feline Thyroid Surgery
Hyperthyroidism is the most commonly diagnosed endocrine disease in cats. Surgery is a widely available curative therapy for hyperthyroid cats. Because of the multiple metabolic changes associated with hyperthyroidism, surgical management can be challenging. Multiple methods of thyroidectomy and their associated levels of morbidity are reviewed.

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2002/07
Feline Thyroid Adenomas Are in Part Associated with Mutations in the G(S Alpha) Gene and Not with Polymorphisms Found in the Thyrotropin Receptor
The etiopathogenesis of feline thyrotoxicosis is unknown. The transmembrane part (gene codons 480-640) of the thyrotropin receptor (TSHR) gene of hyperthyroid cats has already been investigated for the presence of stimulating mutations.

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2002/07
Evaluation of an in-house enzyme-linked immunosorbent assay for quantitative measurement of serum total thyroxine concentration in dogs and cats
OBJECTIVE: To compare serum total thyroxine (T4) concentrations obtained with an in-house ELISA and a validated radioimmunoassay (RIA). DESIGN: Laboratory trial. SAMPLE POPULATION: 50 canine and 50 feline serum samples submitted for measurement of total T4 concentration with the RIA; samples were selected to represent a wide range of concentrations (< 6 to 167 nmol/L).

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2002/06
Prevalence of Systolic Hypertension in Cats with Chronic Renal Failure at Initial Evaluation
OBJECTIVE: To determine prevalence of systolic hypertension and associated risk factors in cats with chronic renal failure evaluated in first-opinion practice.

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2002/06
Estimation of Iodine Status in Cats

Feline hyperthyroidism is the most common endocrine disorder of middle-aged to old cats in the United States. In Germany, the latest investigations have shown increasing fe- line hyperthyroidism (1,2). The role of iodine in feline hyper- thyroidism is still not clear. A deficient or excess level of dietary iodine has been suggested by several authors as an important factor in the development of feline hyperthyroidism (3).

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2002/06
Bioavailability of transdermal methimazole in a pluronic lecithin organogel (PLO) in healthy cats.
The results of this study indicate generally low to undetectable bioavailability of methimazole in a lecithin/pluronic gel given as a single transdermal dose to healthy cats, although one individual cat did achieve nearly 100% transdermal bioavailability relative to the oral route.

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2002/05
Thyroid Nodules In Euthyroid Cats: A Matter Of Age Or Time?
Retrospective studies support the presence of a subset of cats with nodules not inducing clinical hyperthyroidism. Furthermore, new data provided indicate that early surgical removal of the enlarged thyroid glands is frequently validated by abnormal histopathology.

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2002/05
Prevalence of Feline Hyperthyroidism in Osaka and the Chugoku Region

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2002/04
External and Internal Influences on Disease Risk in Cats

Owners surrender millions of cats to animal shelters each year for euthanasia. Inappropriate elimination, most commonly associated with urologic signs, was the most common reason given for abandoning the cat. Oral disease recently was reported to be the most common health problem of cats, with a prevalence ranging from 23 to 67% of cats examined.

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2002/02
Primary Hyperparathyroidism and Concurrent Hyperthyroidism in a Cat
A cat was presented for anorexia and vomiting. Hyperthyroidism and primary hyperparathyroidism were diagnosed.

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2002/02
Identification And Concentration Of Soy Isoflavones In Commercial Cat Foods
Genistein and daidzein are common constituents of commercial cat foods. Predictors of isoflavone content included ingredient labeling, food type, and food cost. Soy isoflavones in some commercial cat foods were detected in amounts predicted to have a biological effect.

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2002/02
Feline hyperthyroidism: advances towards novel molecular therapeutics
Feline hyperthyroidism is the most common endocrine disorder of the elderly cat. Traditionally, the disease is treated by surgical thyroidectomy, medical management with antithyroid drugs or radiation therapy using iodine-131.

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2002/02
Cloning of the cat TSH receptor and evidence against an autoimmune etiology of feline hyperthyroidism
Cats are the only nonhuman mammalian species with a high incidence of hyperthyroidism, and a better understanding of the pathogenesis of feline hyperthyroidism is of clinical relevance for veterinary medicine. The etiology of this disease in cats remains controversial. Both an intrinsic autonomy of growth and function of follicular cells as well as an autoimmune-related mechanism have been proposed.

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2002/01
Serum from Cats with Hyperthyroidism Does Not Activate Feline Thyrotropin Receptors

Background Hyperthyroidism is far more common in cats than in other animals. The usual causes are a toxic uninod- ular or multinodular goiter, but a few cats seem to have a diffuse goiter, raising the possibility that they have the feline counterpart of Graves’ disease. This study was done to clone the feline thyrotropin (TSH) receptor, determine its structure, and define the properties of the receptor, includ- ing whether it can be activated by serum or serum immunoglobulins from cats with hyperthyroidism or humans with hyperthyroidism caused by Graves’ disease. In addition, the effect of serum from cats and humans with hyperthyroidism was compared in a radioreceptor assay using porcine TSH receptors.

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2002/01
Percutaneous ultrasonographically guided radiofrequency heat ablation for treatment of hyperthyroidism in cats.
The purpose of this study was to evaluate the efficacy of radiofrequency heat ablation for treatment of cats with naturally occurring hyperthyroidism. Unipolar radiofrequency heat ablation is feasible and effective as a short-term treatment for feline hyper-thyroidism, but has not been effective as a permanent treatment like radioiodine therapy.

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2001/12
Cholelithiasis and Hyperthyroidism in a Cat

A 14-year-old domestic short-hair cat presented with a history of intermittent malaise and increased drinking. A diagnosis of hyperthyroidism and cholelithiasis was made by a combination of blood testing, radiography and ultrasonography.

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2001/09
The effect of methimazole on thyroid uptake of pertechnetate and radioiodine in normal cats
Many hyperthyroid cats referred for thyroid imaging and 131I therapy are concurrently or recently receiving antithyroid medications. The effect of the antithyroid drug, methimazole, on thyroid uptake of 99mTcO4 and 123I was evaluated in 8 normal cats.

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2001/09
Identifying and Managing Feline Congenital Hypothyroidism

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2001/09
Hypophysectomy as a Treatment for Canine and Feline Cushing's Disease
The microsurgical technique of transsphenoidal hypophysectomy performed with the dogs and cats positioned in sternal recumbency enables the treatment of Cushing's disease, independent of skull type, in a safe and effective manner.

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2001/09
Feline hyperthyroidism. Diagnostics and therapeutics
Today, hyperthyroid cats are less symptomatic than those 10 or 15 years ago, and early diagnosis impacts the range and severity of the routine clinicopathological abnormalities traditionally associated with this disorder.

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2001/09
Feline Endocrinology Update
This article highlights the advances in feline endocrinology, excluding diabetes mellitus and hyperadrenocorticism, which have recently been reviewed elsewhere. The goal will be to provide clinically relevant information regarding pathogenesis, diagnosis, and treatment options for these feline endocrine disorders.

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2001/06
The Inhibitory G Protein, Gi2, Shows Decreased Expression in Adenomatous Thyroid Tissue from Hyperthyroid Cats

Feline hyperthyroidism is a common endocrinopathy in cats that resembles toxic nodular goiter (TNG) in humans. Abnormalities of the TSH receptor-G protein-mediated signal transduction cascade have been shown to be involved in the pathogenesis of human TNG. Previous work from our laboratory has implicated similar pathogenic mechanisms involved in feline hyperthyroidism. We demonstrated that adenomatous thyroid tissue from hyperthyroid cats showed significantly decreased expression of inhibitory G proteins (Gi).

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2001/06
Selenium Status Of Cats In Four Regions Of The World And Comparison With Reported Incidence Of Hyperthyroidism In Cats In Those Regions
Cats have higher Se concentrations in plasma, compared with values for other species. However, Se status alone does not appear to affect the incidence of hyperthyroidism in cats. High Se concentrations may have implications for health of cats if such concentrations are influenced by the amount of that micronutrient included in diets.

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2001/06
Evaluation of Proteinuria in Hyperthyroid Cats
Many cats are diagnosed with renal failure (RF) following treatment for hyperthyroidism.It is uncertain whether this is due to the deleterious effects of hyperthyroidism per se or is a reflection of the high incidence of RF in the geriatric feline population. This study was designed to determine the incidence of proteinuria in cats before and after treatment for hyperthyroidism and to correlate these findings with the development of azotemia.

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2001/06
99m Tc-Pertechnetate Scintigraphy in Hyperthyroid Cats with Normal Serum Thyroxine Concentrations (Abstract)
We previously reported, that hyperthyroid cats suffering from severe non-thyroidal illness (sick hyperthyroid cats) were indistinguishable from sick euthyroid cats based on serum T4 and on thyrotropin-releasing hormone (TRH) stimulation test. Limitation of the TRH stimulation test was mainly poor specificity.
The purpose of this prospective study was to evaluate the usefulness of thyroid pertechnetate scintigraphy for assessment of thyroid function in a population of cats with clinically suspected hyperthyroidism, and normal serum T4 concentration and to evaluate its potential superiority over TRH stimulation test.

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2001/05
Functional cystic thyroid adenoma in a cat.
Possible causes of cystic ventral cervical masses in cats include thyroid, thyroglossal duct, and parathyroid cysts; however, the possibility that such masses represent cystic thyroid adenomas or cystic thyroid carcinomas should also be considered.

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2001/04
Use of Percutaneous Ethanol Injection for Treatment of Bilateral Hyperplastic Thyroid Nodules in Cats
Percutaneous ethanol ablation of bilateral thyroid nodules as a treatment for cats with hyperthyroidism is not recommended. This treatment is not as efficacious as the medical and surgical treatments presently used.

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2001/04
Percutaneous ethanol injection for treatment of unilateral hyperplastic thyroid nodules in cats

Hyperthyroidism is a commonly diag- nosed endocrine disease in cats. Current treatment options include long- term use of antithyroid medications, thy- roidectomy, and administration of radioac- tive iodine ('"I).' All 3 of these treatment , modalities are commonly used and effec- tive. Each also has disadvantages.

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2001/04
Characterization of the Feline Thyroglobulin Promoter
The feline thyroglobulin promoter was identified by a combination of standard polymerase chain reaction (PCR) techniques, using primers designed according to regions of homology in published sequences from other species, then adaptor ligated PCR. The data presented here demonstrate that the feline thyroglobulin promoter may provide a targeting mechanism for somatic gene therapy of feline thyroid disease.

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2001/03
Thyrotropin-Releasing Hormone Stimulation Test to Assess Thyroid Function in Severely Sick Cats
Based on the results of serum T4 determinations and the TRH stimulation tests alone, it was not possible to document hyperthyroidism in many critically ill cats with severe nonthyroidal illnesses. This study demonstrates the limitations in laboratory evaluations of severely sick cats. In many of these critically ill cats their otherwise elevated thyroid hormone levels were suppressed into the normal range by their concurrent nonthyroidal disease.

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2001/03
Thyroid Function Tests--What Do They Really Tell Us?

Regulation of circulating thyroid hormones is a complex process that involves the hypothalamus, pituitary gland, thyroid gland, plasma transport proteins, and cellular uptake and metabolism of thyroid hormones. The hypo- thalamus produces thyrotropin-releasing hormone (TRH), which stimulates pituitary secretion of thyrotropin (TSH) and enhances its bioactivity.

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2001/03
Feline Hypertension: Clinical Findings and Response to Antihypertensive Treatment in 30 Cases
Systolic hypertension was diagnosed in 30 cats. At diagnosis, 16 of those were found to be in chronic renal failure only, while five were azotaemic and either receiving treatment for hyperthyroidism (four cases) or were untreated hyperthyroid cases (one case). Two cases were untreated hyperthyroid cases with no evidence of azotaemia and the remaining seven cases had no definitive diagnosis of the underlying cause of their hypertension.

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2001/02
Measurement of Serum Concentrations of Free Thyroxine, Total Thyroxine, and Total Triiodothyronine in Cats with Hyperthyroidism and Cats with Nonthyroidal Disease
Results indicate that determination of free T4 concentration is useful in the diagnosis of hyperthyroidism, especially in cats in which hyperthyroidism is suspected but total T4 and T3 concentrations are within reference ranges. However, because some cats with nonthyroidal disease have high serum free T4 concentrations, hyperthyroidism should not be diagnosed solely on the finding of a high free T4 concentration.

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2001/01
Long-Term Health and Predictors of Survival for Hyperthyroid Cats Treated with Iodine 131
Two hundred thirty-one cats treated with radioactive iodine at the Texas Veterinary Medical Teaching Hospital were followed for a median of 25 months and tables predicting survival after diagnosis and treatment of hyperthyroidism for various age and sex combinations were created. This study provides estimates of duration of survival for cats successfully treated for hyperthyroidism with radioactive iodine, which can be useful in assisting with client treatment decisions.

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2000/11
Culture and Thyroglobulin Expression of Feline Normal and Hyperthyroid Thyrocytes

Feline hyperthyroidism is a common, spontaneously occurring endocrine disease seen in middle-older aged cats. It is similar both histologically and functionally to human toxic nodular goiter, seen in a comparable population of middle-older aged humans. Several etiologies for human toxic nodular goiter have been proposed including abnormalities in number or function of components of the cell surface TSH receptor G protein signal transduction system.

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2000/09
Ocular Lesions Associated with Systemic Hypertension in Cats: 69 Cases (1985-1998)

OBJECTIVE: To characterize clinical and clinicopathologic findings, response to treatment, and causes of systemic hypertension in cats with hypertensive retinopathy.

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2000/09
Evaluation Of Dietary and Environmental Risk Factors For Hyperthyroidism In Cats
This study suggests that cats which eat certain flavors (fish or liver and giblet flavors) of canned cat food may have a significantly increased risk of hyperthyroidism.This study found no link between the development of hyperthyroidism and exposure to regular treatment with flea sprays or powders; exposure to lawn herbicides, fertilizers or powders; or living indoors.

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2000/09
Ectopic lingual thyroid tissue in a cat
Ectopic thyroid tissue was identified at the base of the tongue in a 9-year-old, euthyroid, domestic shorthair cat.

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2000/08
Epidemiological Aspects of Feline Hyperthyroidism
A questionnaire-based case-control study involving 375 New Zealand cats was conducted to examine associations between putative risk factors and feline hyperthyroidism. Data was collected for cat and owner demography, medical history, indoor and outdoor environment and diet and feeding practices from the owners of 125 hyperthyroid case cats, 125 randomly selected control cats and 125 cats matched to cases with regard to sex and age (± 1.5 years).

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2000/08
Altered Expression of G Proteins in Thyroid Gland Adenomas Obtained from Hyperthyroid Cats
The finding of decreased amount of Gi[alpha] in thyroid gland adenomas may indicate that G[i] plays a role in the inhibition of growth and differentiation of the feline thyroid gland. Decreased amounts of Gi[alpha] could reduce the overall inhibitory effect on adenyl cyclase leading to abnormally high concentrations of cAMP, resulting in cell growth and differentiation.

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2000/07
Feline hyperthyroidism: spectrum of clinical presentions and response to carbimazole therapy
OBJECTIVE: To determine the spectrum of clinical presentations of hyperthyroidism in cats and response to carbimazole therapy by analysis of historical, clinical and laboratory data.

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2000/05
Effects of Methimazole on Renal Function in Cats with Hyperthyroidism
The results of this study agree with others that hyperthyroidism increases GFR, and treatment with methimazole, surgical thyroidectomy, or radioiodine decreases GFR. Isosthenuria was present prior to methimazole treatment in the three hyperthyroid cats that developed azotemia after treatment. Thus, hyperthyroid cats with isosthenuria prior to treatment may be at risk for development of renal failure after euthyroidism is established, so a pretreatment urinalysis is indicated in all cases.

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2000/03
Prevalence of Ocular Abnormalities in Cats with Hyperthyroidism
Active retinal lesions were only observed in 3 hyperthyroid cats (3%). The results of this study indicate that hyperthyroidism does not seem to be a frequent cause of abnormalities in the eyes of cats.

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2000/02
Tissue sources of serum alkaline phosphatase in 34 hyperthyroid cats: a qualitative and quantitative study.
In hyperthyroid cats, there was a significant correlation between the serum L-thyroxine concentrations and the SALP concentrations. These findings suggest pathological changes in both bone and liver in most cases of feline thyrotoxicosis.

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2000/02
Tissue Sources of Serum Alkaline Phosphatase in 34 Hyperthyroid Cats: A Qualitative and Quantitative Study
The concentration of serum alkaline phosphatase (SALP) is commonly elevated in hyperthyroid cats. In hyperthyroid cats, there was a significant correlation between the serum L-thyroxine concentrations and the SALP concentrations. These findings suggest pathological changes in both bone and liver in most cases of feline thyrotoxicosis.

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2000/02
Thyroid Hormone Deiodination in the Domestic Cat
We have investigated thyroid hormone deiodination in the liver, kidney and thyroid of the domestic cat. This study demonstrates that cats and rats express IDI in the liver and kidney in similar concentrations; however, the feline enzyme appears unable to utilise rT(3) as a substrate under physiological conditions.

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2000/01
Prothrombin, Activated Partial Thromboplastin, and Proteins Induced by Vitamin K Absence or Antagonists Clotting Times in 20 Hyperthyroid Cats Before and After Methimazole Treatment
Seemingly, doses of methimazole commonly used to treat hyperthyroidism in cats do not cause alteration in PT and APTT and only rarely prolong PIVKA clotting time. Nevertheless, abnormal PIVKA clotting time may explain bleeding tendencies unassociated with thrombocytopenia in methimazole-treated hyperthyroid cats.

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2000/01
Effect of Specimen Collection and Storage on Blood Glucose and Lactate Concentrations in Healthy, Hyperthyroid and Diabetic Cats
The objective of this study was to compare and investigate differences in glucose and lactate concentrations in sodium fluoride/potassium oxalate (NaF/Ox) plasma and serum in healthy cats and cats with metabolic disease.

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1999/12
Follicle-Forming Cat Thyroid Cell Lines Synthesizing Extracellular Matrix and Basal Membrane Components: A New Tool for the Study of Thyroidal Morphogenesis
Interactions between follicular epithelial cells and extracellular matrix (ECM) are supposed to play an important role in the development and maintenance of thyroid tissue architecture. In the present study we have therefore investigated the synthesis of ECM components by a feline thyroid cell line which is able to form follicle-like structures in vitro, and also in v-ras-transfected and control-transfected sublines.

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1999/12
Feline Hyperthyroidism in Cats with Normal T4 Levels: The Importance of Scintigraphy
Purpose: To compare T4 levels and thyroid scintigraphy in the evaluation of feline hyperthyroidism. Emphasis was placed on the scintigraphic results of cats with normal T4 levels as well as evaluating a new method of scintigraphic analysis.

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1999/12
Correlation of Thyroid Scintigraphy with Long Term Response to Radioiodine Therapy in Hyperthyroid Cats (1992- 1998)
Feline hyperthyroidism was first recognized in 1979 and is now the most frequently diagnosed endocrinopathy in cats. Many studies have evaluated dose and response to radioiodine therapy; however, no strong factors have been identified as predictors of treatment outcome, either from pretreatment or short-term follow-up data. The objectives of this retrospective study were to determine if specific factors are predictive of response to radioiodine therapy in hyperthyroid cats.

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1999/11
Serum Fructosamine Concentration in Cats with Overt Hyperthyroidism
Serum fructosamine concentrations in hyperthyroid cats were significantly lower than values in healthy cats due to accelerated plasma protein turnover. Diabetic cats have elevated serum fructosamine concentrations proportional to the degree of hyperglycemia present during the preceding two weeks. Hyperthyroid cats with diabetes mellitus should have lowered serum fructosamine concentrations which may fall within the euglycemic range of normal cats, or below. Therefore, serum fructosamine concentration should not be used to diagnose or assess the adequacy of treatment of diabetes in cats with concurrent hyperthyroidism that has not been controlled for at least six weeks. Additionally concentration of serum fructosamine in hyperthyroid cats should not be used to differentiate between diabetes mellitus and transitory stress-related hyperglycemia.

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1999/10
Serum Fructosamine Concentrations in Hyperthyroid Cats
Serum fructosamine concentrations were measured in 35 healthy cats and in 30 hyperthyroid cats before and 30 days after curative radioiodine ((131)I) treatment.

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1999/09
Surgical Options for the Treatment of Hyperthyroidism in the Cat
Since more than 80% of hyperthyroid cats have neoplastic changes in both thyroid glands, bilateral thyroidectomy is necessary for treatment of the majority of hyperthyroid cats. Several different thyroidectomy techniques have been developed in an attempt to minimize potential post-operative complications associated with bilateral thyroidectomy such as hypocalcemia or recurrence of hyperthyroidism. Damage to or removal of all four parathyroid glands during bilateral thyroidectomy causes hypocalcemia, the most common post-operative complication. Recurrence of hyperthyroidism can occur months after initial thyroidectomy if residual adenomatous thyroid tissue is retained in the surgical site. Thyroidectomy is a very effective treatment option for hyperthyroid cats.

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1999/08
When the Thyroid Goes Wild: A Roundtable Discussion of Feline Hyperthyroidism

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1999/08
Hyperthyroidism: Incidence in the Cat

20 cases of feline hyperthyroidism are reported. The examinations were performed during 13 years. The hyperthyroid cats were diagnosed of about 23,000 cats examined in two internal veterinary clinics Giessen und Munich). Diagnosis can be performed with RIA or ELISA methods. Scintigrams had been done for examination of localization and function. Treatments were performed with radioactive iodine, thyroidectomy or thyrostatic drugs.

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1999/07
Use of Propranolol and Potassium Iodate in the Presurgical Management of Hyperthyroid Cats
Based on the findings of this study, propranolol followed by potassium iodate is an effective alternative preoperative treatment for hyperthyroidism in cats. Liver function should be monitored, particularly when iodate treatment is added to the treatment regime. The finding that propranolol treatment decreases serum T3 is consistent with findings in man that the drug inhibits deiodinase activity, preventing conversion of T4 to the more active T3.

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1999/07
Evaluation of Environmental, Nutritional, and Host Factors in Cats with Hyperthyroidism
The pathologic changes associated with hyperthyroidism (adenomatous hyperplasia, adenoma of the thyroid gland) have been well characterized in cats, but the pathogenesis of these changes remains unclear. Results suggested a 2- to 3-fold increase in risk of developing hyperthyroidism among cats eating a diet composed mostly of canned cat food and a 3-fold increase in risk among those using cat litter. In contrast, the use of commercial flea products did not retain a strong association. The results of this study indicate that further research into dietary and other potentially important environmental factors (e.g., cat litter) is warranted.

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1999/06
Molecular Mechanisms of Feline Hyperthyroidism

Hyperthyroidism is the most common endocrinopathy in cats, affecting a large percentage of middle to older aged cats. Since its recognition as a clinical entity some 20 years ago, it has been diagnosed with increasing frequency; however, the pathogenesis of the disease is not currently understood. Feline hyperthyroidism most often results from benign adenomatous hyperplasia of the thyrold and is clinically and pathologically similar to toxic nodular goiter or Plummer’s disease in humans. Interestingly most cats have bilateral disease. Because of its impact on feline health and similarity to human disease study into the cellular and molecular mechanisms of feline hyperthyroid diseases may be important to our understanding of this disease and other hyperfunctioning endocrine diseases.

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1999/06
Effects of Methimazole on Hemostatic Parameters in Cats with Hyperthyroidism

Thrombocytopenia is a rare but well recognized side effect of methimazole (Tapazole) treatment in cats. Methimazole has also been implicated in producing a bleeding tendency in cats with a normal platelet count. Because of that, some have recommended not using methimazole to make cats euthyroid prior to surgery, in the belief that this bleeding tendency would increase the bleeding associated with surgery and therefore surgical risk.

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1999/05
The Effect of Formulation on Radioiodide Thyroid Uptake in the Hyperthyroid Cat
This investigation was designed to compare in vitro dissolution profiles from sodium iodide capsules with radioiodide thyroid uptake in hyperthyroid cats using sodium iodide capsules prepared with a formulation exhibiting a complete release of radioiodide (I-123) in vitro and a formulation with an incomplete release of radioiodide.

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1999/04
Thyroid Adenomatous Hyperplasia in Euthyroid Cats

This study describes a population of cats with a histologic diagnosis of thyroid adenomatous hyperplasia (TAH) with normal serum thyroxine concentrations and the absence of clinical hyperthyroidism.

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1999/03
Overexpression of c-Ras in hyperplasia and adenomas of the feline thyroid gland: an immunohistochemical analysis of 34 cases.
These results indicated that overexpression of c-ras was highly associated with areas of nodular follicular hyperplasia/adenomas of feline thyroid glands, and mutations in this oncogene may play a role in the etiopathogenesis of hyperthyroidism in cats.

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1999/03
Medical Therapy of Feline Hyperthyroidism
Antithyroid medications and radioiodine constitute the two main medical options. Methimazole and carbimazole are effective in most cats, but monitoring is required to assess efficacy of therapy and development of side effects. Ipodate is an oral agent that may be used as an alternative in some cats. Radioiodine therapy is also highly successful. Although [beta]-adrenergic blockers do not affect thyroid hormone concentration, they reverse some of the effects of the hyperthyroid state and can be used in combination with antithyroid medications or surgery.

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1999/01
[Radioiodine Therapy in Veterinary Medicine: Treatment of Hyperthyroidism in a Cat]
A nine-year-old cat with symptoms of a distinct hyperthyroidism was presented at the University Hospital of the RWTH Aachen. The clinical symptoms as well as the diagnostic procedures performed at the hospital confirmed the diagnosis. After five weeks of thyreostatic medication a regular metabolism of the thyroid gland was established, followed by a radioiodine therapy with 70.3 MBq 131-iodine. Subsequently, the cat was hospitalized for two days before it could be released in good condition. Six weeks after treatment the former drastically reduced weight of the cat recovered to near normal. Even though the chemical analysis detected a discrete hyperthyroidism, clinical symptoms were no longer prominent. Three months after treatment, the final examination showed a regular metabolism of the thyroid gland without a specific thyroidal medication. The presented case illustrates that radioiodine therapy is a safe and efficient treatment of thyroidal dysfunctions in veterinary medicine.

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1999/01
Electrocardiographic and Radiographic Changes in Cats With Hyperthyroidism: Comparison of Populations Evaluated During 1992-1993 vs. 1979-1982
Two populations (1992 to 1993 and 1979 to 1982) of confirmed hyperthyroid cats were compared to determine whether the incidence of certain cardiovascular specific manifestations of feline thyrotoxicosis had experienced similar changes. Sinus tachycardia, which is the most commonly recognized cardiac manifestation of feline thyrotoxicosis, was not as prevalent in the 1993 group when compared to the 1982 group. Thoracic radiographs were deemed necessary in a larger proportion of the 1982 group when compared to the 1993 group. These findings suggest that feline hyperthyroidism is being diagnosed earlier and with less severe clinical signs than when studied a decade ago.

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1998/11
Mechanism of Hyperthyroidism-Induced Renal Hypertrophy in Rats
It is well known that renal hypertrophy is induced by hyperthyroidism; however, the mechanism is not fully understood.

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1998/09
A First Feline Case of Cardiomyopathy Associated With Hyperthyroidism due to Thyroid Adenoma in Japan
A 13-year-old castrated male Persian cat was presented with depression, anorexia, and weight loss. Radiographic and electrocardiographical examinations revealed cardiomegaly and sinus tachycardia. Cardiac ultrasonography indicated hypertrophy of the left ventricular free wall and interventricular septum, and left atrial enlargement. Elevated serum T3 and T4 levels were observed, and thyroid adenoma was confirmed by histopathology. Based on these findings, the cat was diagnosed as cardiomyopathy associated with hyperthyroidism induced by thyroid tumor. This report describes the first feline case of cardiomyopathy associated with hyperthyroidism in Japan.

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1998/06
Evaluation of Enviornmental, Nutritional, and Host Factors in Cats with Hyperthyroidism
The pathologic changes associated with hyperthyroidism (ie, adenomatous hyperplasia and adenoma of the thyroid gland) have been well-characterized in cats, but the pathogenesis of these changes remains unclear. In this study, we undertook a case control study to search for potential risk factors for this disease.

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1998/06
Controversies in the Management of Feline Hyperthyroidism -- Surgical Excision
The surgical management of feline hyperthyroidism is associated with many benefits compared to prolonged medical management and a few benefits compared to radioiodine therapy. Surgical therapy is not with out its drawbacks and complications,however. Therefore, it is best to weigh the pros and cons of each type of therapy and choose the one that is best suited to an individual patient.

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1998/06
Altered G Protein Expression in Thyroid Adenomas from Hyperthyroid Cats
Hyperthyroidism is a common endocrinopathy in geriatric cats that resembles toxic nodular goiter in humans. It results from single or multiple hyperplastic thyroid nodules that retain the ability to secrete functional thyroid hormone.

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1998/05
Percutaneous Ethanol Treatment of Hyperthyroidism in a Cat
This case report describes the treatment of hyperthyroidism in a 8 1/2 year old female spayed Domestic Shorthair with intrathyroid injection of ethanol. The authors believe that although this technique has been proven to be effective in humans, further study should be conducted in animals before recommending it as an acceptable treatment modality in the cat.

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1998/05
Efficacy of Parathyroid Gland Autotransplantation in Maintaining Serum Calcium Concentrations After Bilateral Thyroparathyroidectomy in Cats
Feline hyperthyroidism is a multisystemic endocrinopathy. While multiple methods of treatment exist, surgical removal of the abnormal thyroid tissue remains the most widely available curative procedure. The most serious complication of bilateral thyroidectomy is postoperative hypocalcemia. Hypoparathyroidism and associated hypocalcemia result from accidental removal of the external parathyroid glands or disruption of their vascular supply. The hypocalcemia often can be severe and life threatening, requiring intensive monitoring and care followed by prolonged supplementation with calcium and vitamin D analogues. While parathyroid autotransplantation greatly reduces morbidity in the parathyroidectomized cat, transplanted normal thyroid tissue was present in at least three of eight cats with thyroparathyroidectomy and autotransplantation. It may be possible to transplant diseased thyroid tissue in a clinical case. This may lead to an ectopic site of thyroid adenoma or adenocarcinoma.

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1998
Radioactive Iodine (Radioiodine) Treatment for Cats with Hyperthyroidism

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1997/Nov
Endocrinopathies. Thyroid and Adrenal Disorders

This article focuses on common adrenal and thyroid diseases in the geriatric patient consisting of hypothyroidism in the dog, hyperthyroidism in the cat, and hyperadrenocorticism in the dog to include clinical signs, diagnosis, and management.

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1997/12
Mutational Analysis of the Thyrotropin Receptor Gene in Sporadic and Familial Feline Thyrotoxicosis
The characterization of a spontaneous animal model equivalent to a human form of thyrotoxicosis would provide a useful resource for the investigation of the human disorder. Feline thyrotoxicosis is the only common form of hyperthyroidism found in domestic or laboratory animals, but its etiopathogenesis remains poorly defined.

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1997/07
Validation of Nonradioactive Chemiluminescent Immunoassay Methods for the Analysis of Thyroxine and Cortisol in Blood Samples Obtained from Dogs, Cats, and Horses
The performances of a radioimmunoassay method, a chemiluminescent immunoassay method, and a chemiluminescent-enzyme immunoassay method were evaluated for the analysis of cortisol and total thyroxine in blood samples obtained from dogs, cats, horses, and humans (reference samples).

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1997/07
Ipodate Treatment of Hyperthyroidism in Cats
lpodate may be a feasible alternative to methimazole for medical treatment of hyperthyroidism in cats, particularly those that cannot tolerate methimazole and are not candidates for surgery or radiotherapy. Cats with severe hyperthyroidism are less likely to respond to ipodate than are cats with mild or moderate disease, and cats in which serum T3 concentration does not return to the reference range are unlikely to have an adequate improve merit in clinical signs.

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1997/06
Thyroidal Radioisotope Uptake in Euthyroid Cats: A Comparison between 131i and 99mTcO4

Two thyroidal evaluation systems in euthyroid cats (n = 12) were compared. A single, confirmed hyperthyroid cat was included for interest.

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1997/05
Changes in Renal Function in Cats Following Treatment of Hyperthyroidism Using 131I
It was concluded that significant declines in renal function occur after treatment of hyperthyroidism and this decline is clinically important in cats with renal disease. Pretreatment measurement of GFR is valuable in detecting subclinical renal disease and in predicting which cats may have clinically important declines in renal function following treatment.

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1997/04
Pharmacokinetics of Propranolol in Healthy Cats During Euthyroid and Hyperthyroid States
OBJECTIVE: To examine the pharmacokinetic profile of propranolol in cats before and during experimentally induced hyperthyroidism.

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1997/03
Update on the Medical Management of Hyperthyroidism

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1997/01
Investigation of the effects of hyperthyroidism on renal function in the cat.
This study evaluated the effects of thyroxine on renal function in the cat. Administration of high doses of exogenous thyroxine to cats results in significant stimulation of renal function.

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1996/12
Study of calcium homeostasis in feline hyperthyroidism.
Hyperparathyroidism occurred in 77 per cent of hyperthyroid cats, with parathyroid hormone concentrations reaching up to 19 times the upper limit of the normal range. The etiology, significance and reversibility of hyperparathyroidism in feline hyperthyroidism remains to be established but could have important implications for both bone strength and renal function.

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1996/12
Alkaline phosphatase bone isoenzyme and osteocalcin in the serum of hyperthyroid cats.
This study concluded that hyperthyroid cats do have altered bone metabolism, although it is usually clinically insignificant.

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1996/11
Serum Free Thyroxine Concentrations Measured by Chemiluminescence in Hyperthyroid and Euthyroid Cats
Serum free thyroxine (FT4) concentrations using chemiluminescence were measured in hyperthyroid cats (n = 72) and clinically normal cats (n = 129) to establish reference values and to determine if this method could be a useful alternative to total T4 (TT4) measurement by radioimmunoassay (RIA).

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1996/10
Total Thyroxine, Free Thyroxine, Pertechnetate Scan and T3 Suppression Test Results in Cats with Occult Hyperthyroidism (Abstract)

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1996/09
Hyperthyroid Cats: Complications of the Disease and Our Therapy
Feline hyperthyroidism results from excessive circulating levels of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Hyperthyroidism, the most frequently occurring endocrine disorder of the cat, is most commonly a result of a functional thyroid adenoma and/or adenomatous hyperplasia. Both thyroid lobes are involved in the majority of cases. Thyroid carcinoma is a rare cause of hyperthyroidism in the eat. The cause of the adenoma is unknown. The disease affects middle-age to older cats; most cats are nine years old or older (range 5·22 years).

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1996/07
Serum Thyroxine and Triiodothyronine Responses of Hyperthyroid Cats to Thyrotropin
OBJECTIVE: To document circulating total thyroxine (T4) and triiodothyronine (T3) responses after administration of thyrotropin (thyroid-stimulating hormone [TSH]) to hyperthyroid and healthy cats and assess the value of these responses as an additional diagnostic test for hyperthyroidism.

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1996/06
Effect of illness not associated with the thyroid gland on serum total and free thyroxine concentrations in cats
OBJECTIVE--To determine circulating concentrations and fate of total and free thyroxine (T4) in cats with various illnesses not associated with the thyroid glands (nonthyroidal illnesses).

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1996/04
Decision Making in the Treatmment for Hyperthyroidism in Cats

FELINE hyperthyroidism is a frequently encountered disorder with which practitioners are now familiar. Currently, there are three methods of treatment for the hyperthyroid cat. This article looks at the advantages and disadvantages of each and discusses the factors to bear in mind when formulating a treatment regimen for an individual animal.

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1996/03
Effect of treatment of hyperthyroidism on renal function in cats.
Reduction of serum T4 concentrations after treatment of hyperthyroidism may result in azotemia in older cats with chronic renal disease. Treating azotemic hyperthyroid cats with methimazole until it can be determined whether correction of the hyperthyroid state will exacerbate the azotemia may be prudent.

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1996/01
Feline Hyperthyroidism: Efficacy Of Treatment Using Volumetric Analysis For Radioiodine Dose Calculation
The administration of a dose of radioiodine based solely on the volume of hyperfunctioning thyroid tissue as estimated from the pertechnetate scan may be inadequate for those patients with extremely elevated serum thyroxine levels or large thyroid glands, and oral administration of radioiodine is not recommended for the treatment of feline hyperthyroidism.

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1996/
Unilateral Extracapsular Thyroidectomy for a Non-Functional Cystic Thyroid Adenoma.Australian Veterinary Practitioner, 1996. 26: p.174-177.

This case report describesa non-functional cystic thyroid adenomain an 1l-year-old, female Siamese. The cat presentedwith a right-sided ventral cervical swelling. Serial serumthyroxine analysis over a l2-month period revealed a euthyroid state.

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1995/12
Radioiodine treatment of 524 cats with hyperthyroidism.
Results of the study confirms that subcutaneous administration of radioiodine provides a safe and effective means of treating hyperthyroidism in cats.

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1995/11
Immunohistochemical Distribution Pattern of Intermediate Filament Proteins in 50 Feline Neoplasms
Twenty-eight epithelial and 22 nonepithelial feline tumors were studied immunohistochemically. Epithelial tumors were 10 squamous cell carcinomas, two basal cell tumors, two sebaceous gland carcinomas, three apocrine gland carcinomas, three thyroid papillary carcinomas, one thyroid solid carcinoma, one renal clear cell carcinoma, one renal papillary carcinoma, one endometrial carcinoma, and four lung bronchioloalveolar carcinomas.

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1995/11
Feline Thyroidectomy: A Simplified Technique That Preserves Parathyroid Function
Surgery is a practical method for treating feline hyperthyroidism. But you may be a little unsure of your surgical skills. If so, this modified technique was designed with you in mind.

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1995/10
Response to high-dose radioactive iodine administration in cats with thyroid carcinoma that had previously undergone surgery.
There were no complications associated with 131I treatment, and clinical signs resolved in all cats. All 7 cats became hypothyroid after treatment.

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1995/06
Somatic Mutations Causing Constitutive Activity of the Thyrotropin Receptor Are the Major Cause of Hyperfunctioning Thyroid Adenomas: Identification of Additional Mutations Activating Both the Cyclic Adenosine 3',5'-Monophosphate and Inositol Phosphate-Ca2+ Cascades
A series of somatic mutations of the TSH receptor gene have been demonstrated in hyperfunctioning thyroid adenomas. The mutations studied up to now cause constitutive (i.e. TSH-independent) activation of the cAMP-regulatory cascade only.

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1995/05
The Use of Subcutaneous Administration of Radio-Iodine for the Treatment of Feline Hyperthyroidism - A Study of Nine Cases

Nine cats were given a fixed dose of radio-Iodine by subcutaneous Injection for the treatment of hyperthyroidism. In this study, It was found the subcutaneous administration of radio-Iodine to be both efficacious and easily performed. A dose of 111-148 MBq per cat appears to be sufficient to treat most cases of feline hyperthyroidism.

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1995/04
Treatment of thyroid carcinoma in dogs by surgical resection alone: 20 cases (1981-1989)

Of 82 dogs with thyroid carcinoma seen between January 1981 and October 1989, 20 had freely movable tumors without evidence of metastasis and were treated with surgical excision alone.

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1995/02
Changes in clinical and laboratory findings in cats with hyperthyroidism from 1983 to 1993.
Overall, the frequency and severity of many clinical features of hyperthyroidism in casts has decreased over the past 10 years since the first cases of the disease were reported.

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1995/01
The Prevalence of Feline Immunodeficiency Virus Infection in Hyperthyroid Cats
The cause of hyperthyroidism in cats remains elusive. Clear risk factors for hyperthyroidism other than age have not been identified. The results of this study suggest that the involvement of FIV in the pathogenesis of hyperthyroidism in cats is unlikely.

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1994/12
Prospective randomized comparison of intravenous versus subcutaneous administration of radioiodine for treatment of hyperthyroidism in cats.
When compared with IV administration, SC administration of radioiodine appeared to be as effective for treatment of hyperthyroidism, safer to personnel, and less stressful to the cats.

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1994/12
Ocular disease associated with hypertension in 16 cats
Between 1990 and 1993, 16 cats were referred with acute onset blindness or intraocular haemorrhage. Blood pressure assessment, using the Doppler ultrasonic recording technique in 11 of the cats, proved these cases to be hypertensive. Fifteen cats underwent further investigation, revealing 13 with some degree of renal impairment and one as hyperthyroid. Five underwent cardiac ultrasound and all showed evidence of cardiac hypertrophy. The eyes from four of the cats were examined histologically and showed serous or haemorrhagic retinal detachments with varying degrees of retinal degeneration and a range of ocular hypertensive vascular changes. Two cats had full post mortem examinations which revealed evidence of renal and thyroid pathology.

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1994/12
Dietary Iodine Level and Thyroid Function in the Cat

Feline hyperthyroidism was rarely reported until 1979 (Peterson 1984), but is now diagnosed frequently and is considered a common clinical condition in the cat. Hyperthyroidism is usually associated with nod ular goiter and is not considered to be autoimmune in origin. Reasons for the sudden emergence of this con dition have been sought. Because a large proportion of cats in the Western world are fed commercially produced rations, various investigators (Mumma et al.
1986) have focused on possible dietary causes. In par ticular, inappropriate dietary iodine concentrations have been examined.

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1994/12
Changes in renal function associated with treatment of hyperthyroidism in cats.
This study provides further evidence that treatment of hyperthyroidism can result in impaired renal function. In addition, this study suggests that, in some instances, thyrotoxicosis might mask underlying chronic renal insufficiency.

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1994/11
The Prevalence of Retinopathy in Cats with Systemic Hypertension and Chronic Renal Failure or Hyperthyroidism
- Thirty-six cats with either chronic renal failure or hyperthyroidism were examined. Indirect systemic blood pressure and ophthalmic findings were recorded for each cat. Fifteen of 23 cats (65%) with chronic renal failure had blood pressure readings consistent with hypertension. Twelve of these 15 (80%) had hypertensive retinopathy. Three of 13 cats (23%) with hyperthyroidism had blood pressure readings consistent with hypertension. One of these three cats (33%) had hypertensive retinopathy. The most common findings of hypertensive retinopathy were hemorrhages and intraretinal serous exudates.

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1994/08
Ecg of the Month. High-Grade Second-Degree Av Block and Right Bundle-Branch Block in a Cat

A I3-year-old spayed female domestic shorthair cat was admitted for routine vaccination. The owner was not aware of any problem with the cat at the time of examinatlon. An arrhlthmia was aus- culted, but the remainder of the physical examination was unremarkable. An ECG was performed as part ofthe diagnostic evaluation (Fig 1).

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1994/07
Use of the Thyrotropin Releasing Hormone Stimulation Test to Diagnose Mild Hyperthyroidism in Cats
As a diagnostic test, the TRH stimulation test compares favorably with the T3 suppression test but requires less time and is more convenient to perform.

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1994/07
Ultrasonographic Examination of Cervical Masses in the Dog and Cat

The ultrasonographic appearance of clinically undifferentiated neck masses for which a definitive diagnosis was eventually obtained in nineteen dogs and one cat is presented in this report.

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1994/07
Quantitative Aspects of Thyroid Scintigraphy With Pertechnetate (99mTco4 ) in Cats
It is concluded that the optimal time for visualization of the thyroid by 99mTcO4-scanning is 60 minutes after IV injection of the radionuclide.

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1994/07
Immunity and the Endocrine System

For many years, the immune system was considered an autonomous branch of the intercellular communication system. Endocrine, neural, and neuroendocrine systems seemed to be extensively interconnected, but the immune system appeared to stand alone, It now is evident that the immune and endocrine systems are intimately interconnected.

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1994/07
Acute onset of hypokalemia and muscular weakness in four hyperthyroid cats
Hyperthyroid cats may be prone to disturbances in potassium homeostasis. Clinicians should be aware of potential changes in potassium homeostasis during the treatment of cats with hyperthyroidism.

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1994/06
Serum Free Thyroxine Levels in Cats Maintained on Diets Relatively High or Low in Iodine
Excessive or deficient intake of iodine may play a role in the development of goitre and hyperthyroidism in cats. Previous investigations have shown that the serum free thyroxine level of cats is affected by brief administration of food high or low in iodine content.

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1994/06
Radioactive iodine therapy for feline hyperthyroidism: Efficacy and administration routes
There was no difference in the outcome between the cats injected intravenously or subcutaneously and the latter was considered to be safer and simpler. The administration of an approximated dose of 131I proved to be an effective treatment for hyperthyroidism in 47 (94.0 per cent) of the cats and obviated the need for sophisticated nuclear computer facilities. There may be a lag period in some cases before euthyroidism is achieved and this should be considered before the administration of a second dose. 131I can be administered subcutaneously without untoward effects.

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1994/06
Radioactive Iodine Therapy of Feline Hyperthyroidism: A Simple Method of Dose Estimation and Comparison of Intravenous and Subcutaneous Administration

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1994/05

Diagnostic tests for feline hyperthyroidism
Until recently, the diagnosis of hyperthyroidism in cats was thought to be simple; however, not all cases of the disease are straightforward. Although single resting serum thyroid-hormone determinations may well be adequate to confirm the diagnosis, in many cases, the diagnosis of feline hyperthyroidism requires more extensive investigation.

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1994/05

Considerations in the treatment of feline hyperthyroidism.
Feline hyperthyroidism can be treated with long-term antithyroid drug administration, surgical thyroidectomy, or radioactive iodine. This article discusses the advantages of each of these treatment options and gives specific recommendations on the use of each therapeutic modality.

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1994/05
Update on diagnosis of canine hypothyroidism
Until a clinically useful canine TSH assay is available, a valid test of thyroid hypofunction should (1) take into consideration valid (or at least predictive) measurement of the free T4 concentration in order to factor out the binding effects of drugs and nonthyroidal illness, and (2) should assess thyroid functional reserve.
1994/05
Thyroid Hormone Metabolism: A Comparative Evaluation
Knowledge of thyroid hormone and iodide metabolism is derived from a combination of in vivo and in vitro studies in a variety of mammalian species. Each species provides a unique opportunity to investigate various aspects of normal or altered thyroid hormone physiology. This article compares thyroid hormone and iodide metabolism in dogs, cats, and humans, with emphasis on similarities and differences as well as on areas in which data are not currently available.

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1994/05
Surgical therapy of the thyroid
The surgical treatment of thyroid cancer in the cat involves excision of one or both thyroid glands while sparing at least one parathyroid gland. The most common postoperative complication of bilateral thyroidectomy is transient hypocalcemia. Most feline thyroid tumors are benign, hyperfunctional thyroid adenomas. Surgical excision is usually curative. Canine thyroid cancer is most commonly malignant and nonfunctional. Successful surgical treatment of canine thyroid cancer depends on histologic and early diagnosis prior to metastasis or invasion of the cancer into adjacent structures within the neck.
1994/05
Platelet Function and Antithrombin, Plasminogen, and Fibrinolytic Activities in Cats with Heart Disease

Platelet function, antithrombin and plasminogen activities, and fibrinolytic capabilities in 11 cats with acquired heart disease were compared with results in 4 healthy cats. Of 11 cats with heart disease, 9 had hyperthyroidism with secondary cardiac dysfunction.

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1994/05
Nuclear medicine of the thyroid gland. Scintigraphy and radioiodine therapy
Nuclear medicine may have both diagnostic and therapeutic utility during the evaluation and management of thyroid disease. This article will focus on the use of radionuclide scintigraphy and radioactive iodine therapy in the diagnosis and treatment of thyroid disease in the dog and cat.

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1994/05
Neurologic manifestations of thyroid disease
Animals with polyneuropathy associated with primary hypothyroidism have clinical neurologic signs that range from peripheral vestibular signs, lower motor neuronal deficits, laryngeal paralysis, to megaesophagus; however, a few affected animals also show evidence of a more generalized polyneuropathy with cranial (facial more than vestibular nerve) and spinal nerves being affected most commonly.
1994/05
LONG-TERM FOLLOW-UP OF HYPERTHYROID CATS TREATED WITH IODINE-131
A long-term follow-up study of hyperthymid cats treated with iodine-131 was conducted at the Texas A&M University Veterinary Teaching Hospital. Between January 1985 and December 1990, 255 cats were treated.

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1994/05
Etiopathology of Feline Toxic Nodular Goiter
The basic lesion appears to be an excessive intrinsic growth capacity of some thyroid cells. The factors enhancing the transformation of a normal thyroid into a nodular hyperfunctioning goiter over many years are still unknown. Immunological, environmental, and nutritional factors are the focus of ongoing studies, but an infectious agent can not yet be excluded.

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1994/05
Epidemiology of thyroid diseases of dogs and cats
Data regarding the epidemiology of the thyroid diseases in companion animals are sparse. Published studies providing information regarding the epidemiology of canine hypothyroidism and thyroid neoplasia and feline hyperthyroidism are summarized.
1994/05
Effects of Thyroid Hormone and Thyroid Dysfunction on the Cardiovascular System
Hyperthyroidism is common in the cat andc linically significant cardiovascular manifestations are common and often dramatic. Hyperdynamic systolic function and mild myocardial hypertrophy are common manifestations which may lead to overt congestive and high output heart failure. If signs of congestive heart failure or significant arrhythmias are not evident, specific therapy need only be directed toward restoration of the euthyroid state. In most cases the cardiovascular changes associated with thyroid dysfunction are completely reversible.

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1994/05
Reproductive manifestations of thyroid disease
Thyroid function and reproductive function have many interactions, the scope and mechanism of which are not fully understood.

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1994/05
Etiopathogenesis of canine hypothyroidism
Hypothyroidism in dogs usually results from a progressive destruction of the thyroid, associated with either lymphocytic thyroiditis or idiopathic atrophy. Both syndromes seem to occur with approximately equal frequency. Lymphocytic thyroiditis, which resembles Hashimoto's thyroiditis in humans, is probably an autoimmune disease, and patients often show thyroid autoantibody titers in circulation. By contrast, the pathogenesis of idiopathic atrophy is unclear, and the thyroid seems simply replaced by adipose and connective tissue.

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1994/03
Spontaneous Systemic Hypertension in 24 Cats
Twenty-four cats with spontaneous systemic hypertension were retrospectively studied.

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1994/03
Agarose Gel Electrophoresis of Alkaline Phosphatase Isoenzymes in the Serum of Hyperthyroid Cats
Cats with hyperthyroidism [(increased serum thyroxine (T4)] commonly have increased serum alkaline phosphatase (ALP) activity in addition to other serum biochemical abnormalities. Hyperthyroid cats had increased ALP activity in bands corresponding to isoenzymes originating in the liver, bone, and an unidentified tissue source.

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1994/03
99mTc-pertechnetate imaging of thyroid tumors in dogs: 29 cases (1980-1992)
Thyroid gland scintigraphy was performed in 29 dogs with histologically confirmed thyroid tumors.
1994/01
Ultrasonographic Examination of the Thyroid Gland of Hyperthyroid Cats: Comparison to 99mTc04 Scintigraphy
High-resolution ultrasonography was evaluated as an alternative to 99mTcO4 scintigraphy for examining size and appearance of thyroid glands in hyperthyroid cats. This preliminary study indicates that thyroid ultrasound examination may provide information that is useful for diagnosis and treatment of feline hyperthyroidism. Although ultrasound provides accurate evaluation of the thyroid glands, it cannot replace 99mTc04- scintigraphy for screening of metastatic lesions and ectopic glands.

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1993/12
Thyroid Function Testing

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1993/12
Pathogenesis of Feline Hyperthyroidism

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1993/12
Altered platelet indices in dogs with hypothyroidism and cats with hyperthyroidism
Changes in platelet size reported in human beings with thyroid endocrinopathies also are found in animals so-affected. The pathogenesis of platelet abnormalities in animals with thyroid derangement is unclear and likely is multifactorial.

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1993/09
The appearance of pleural effusion with sodium pertechnetate (99mTcO4-) thyroid scintigraphy

A 13 YEAR OLD, neutered male Siamese cat was referred for i-131 therapy for hyperthyroidism. Two months prior to presentation the cat presented to its local veterinarian with a history of vomiting and an elevated resting serum T, concentration (15.2 pg/dl; normal, 0.8-3.9 pg/dl). The cat was started on 5 mg methimazole PO BID and a recheck resting serum T, concentration collected 3 weeks later was normal (3.5 pg/dl). Approximately 7 weeks later, the cat presented to its local veterinarian with a history of anorexia of 2 weeks duration.

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1993/09
Spontaneous Adult-Onset Hypothyroidism in a Cat
Spontaneous adult-onset hypothyroidism, confirmed by a thyroid-stimulating hormone stimulation test, thyroid biopsy, and response to replacement therapy, is described in a female cat.

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1993/09
Radiographic and Scintigraphic Evidence of Focal Pulmonary Neoplasia in Three Cats With Hyperthyroidism: Diagnostic and Therapeutic Considerations
Increased radionuclide uptake in focal pulmonary lesions and cytologic evaluation of tissue obtained by fine-needle aspiration are not specific for thyroid tissue.

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1993/07
Decreased Orocaecal Transit Time, as Measured by the Exhalation of Hydrogen, in Hyperthyroid Cats
Orocaecal transit time was assessed in healthy cats and cats with hyperthyroidism by means of the breath hydrogen test using a standard liquid meal with lactulose.

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1993/06
Treatment of feline hyperthyroidism using orally administered radioiodine: a study of 40 consecutive cases
Forty cats with hyperthyroidism were treated using 200 to 300 (typically 250) MBq of orally administered 131I. Thirty-six cases (90%) were successfully treated, as assessed by resolution of clinical signs and reduction in plasma thyroxine concentrations to normal or reduced values after treatment.

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1993/05
Influence of Systemic Nonthyroidal Illness on Serum Concentration of Thyroxine in Hyperthyroid Cats
This study's results show that nonthyroidal illness can be associated with normal serum T4 concentrations in cats with apparent hyperthyroidism.

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1993/05
Comparison of the Disposition of Carbimazole and Methimazole in Clinically Normal Cats
The oral disposition of the antithyroid drugs methimazole and carbimazole were compared in nine clinically normal cats.

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1993/04
Use of Breath Hydrogen Measurement to Evaluate Orocecal Transit Time in Cats before and after Treatment for Hyperthyroidism
Orocecal transit time was evaluated in 13 cats diagnosed with hyperthyroidism. Transit was determined by measuring the change in breath hydrogen and methane concentrations following oral administration of a nonabsorbable carbohydrate (lactulose).

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1993/03
THE INSENSITIVITY OF 99mTc PERTECHNETATE FOR DETECTING METASTASES OF A FUNCTIONAL THYROID CARCINOMA IN A DOG
This report describes the use of 99mtechnetium pertechnetate (99mTcO4 and 131Ifor imaging of a metastatic thyroid carcinoma in a dog.

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1993/02
Diagnosis and Treatment of Feline Hyperthyroidism
Hyperthyroidism, a multisystem disorder, should be fully understood by the clinician before anesthesia and surgery is attempted. Thyroid tumors in the cat are usually benign and are functional. Malignant thyroid tumors in cats have been reported and can also be functional. Definitive treatment of hyperthyroidism in cats is either by thyroidectomy or administration of radioactive iodine.

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1993/01
A Prospective Study of 66 Cases of Feline Hyperthyroidism Treated with a Fixed Dose of Intravenous 131-I

Sixty-six cats with hyperthyroidism were treated with a fixed intravenous dose of 150 mBq of radio-iodine. Sixty-two cats (93%) were treated successfully. One cat's serum thyroxine (T4) level remained elevated after therapy.

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1992/11
Glucose Tolerance and Insulin Secretion in Spontaneously Hyperthyroid Cats
Glucose tolerance and insulin secretion after administration of a glucose load were determined in 11 clinically normal cats and 15 cats with spontaneous hyperthyroidism. In six hyperthyroid cats, a glucose tolerance test was repeated after treatment with radioactive iodine (131I). All cats had similar baseline glucose concentrations. However, the cats with hyperthyroidism had a significantly decreased glucose clearance, which was worse after treatment. Hyperthyroidism also caused a marked increase in basal and glucose-stimulated insulin secretion, which was not improved with treatment. It is concluded that hyperthyroidism in cats may lead to long-lasting alterations of glucose tolerance and insulin secretion which may not be reversed by treatment.

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1992/11
Functional Thyroid Follicular Adenocarcinoma in a Captive Mountain Lion (Felis Concolor)

Follicular cell neoplasia of the thyroid glands occurs most often in domestic cats, dogs, and horses, and infrequently in other animal species. Variable clinical signs of hyperthyroidism, such as weight loss, vomiting, diarrhea, heart murmur, polyphagia, hyperactivity, and a palpably enlarged cervical mass, may accompany the neoplasia, especially in cats.

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1992/10
Qualitative and Quantitative Thyroid Imaging in Feline Hyperthyroidism Using Technetium-99m as Pertechnetate
Thyroid imaging using technetium-99m as pertechnetate (99mTcO4) was carried out in five healthy, euthyroid and 37 hyperthyroid cats using both pinhole and parallel-hole collimators.

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1992/09
Historical, Clinical and Laboratory Features of 126 Hyperthyroid Cats
The historical and clinical features and the haematological and biochemical changes in 126 cats with hyperthyroidism are described; 125 of the cats were domestic short- or longhaired, and one was a chinchilla.

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1992/05
Carbimazole Therapy of Feline Hyperthyroidism
The efficacy and safety of carbimazole (CBZ) was studied in a series of 45 hyperthyroid cats. CBZ was used before surgical thyroidectomy in 34 cats. at a dose of 5 mg administered orally every eight hours.

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1992/04
Use of the Triiodothyroxine Suppression Test for Diagnosis of Mild Hyperthyroidism in Cats

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1992/04
Update: Treatment of Hypertension in Dogs and Cats

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1992/04
Transport of the Thyroid Hormones across the Feline Gut Wall
Intestinal absorption of radioiothyroxine (T4*) and of radiotriiodothyronine (T3*) was studied in normal cats (n = 5 for T4* and n = 6 for T3*).

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1992/04
The Value of Thyrotropin (TSH) Stimulation in the Diagnosis of Feline Hyperthyroidism

It has been suggested that the thyrotropin (thyroid stimulating hormone (TSH) stimulation test may be helpful in confirming a diagnosis of feline hyperthyroidism when the serum total thyroxine (T4) concentration is equivocal.

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1992/04
Plasma Lipoprotein Metabolism in Feline Hyperthyroidism
The plasma lipid transport system is extremely sensitive to modification by the thyroid hormones. This is best illustrated by the changes in plasma lipoprotein concentrations and lipolytic enzyme activity tluu occur in humans with hyper- and hypothyroidism. Despite the prevalence of hyperthyroidism in the cat, there are no data on associated changes in lipoprotein metabolism.

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1992/04
Cardiovascular Complications of Feline Hyperthyroidism

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1992/03
Iodine Content of Commercially-Prepared Cat Foods
Twenty-eight varieties of commercially-available cat food (23 canned, 5 dried) were analysed for iodine.

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1992/02
Thyroid Growth Immunoglobulins in Feline Hyperthyroidism
Feline hyperthyroidism bears a strong clinical and pathologic resemblance to toxic nodular goiter in humans. To evaluate whether the observed thyroid growth might be due to circulating thyroid antibodies, as has been postulated in humans, we studied the effect of purified immunoglobulin (Ig) G preparations on a rat thyroid follicular (FRTL-5) cell line.

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1992
Review and Comparison of Neuromuscular and Central Nervous System Manifestations of Hyperthyroidism in Cats and Humans

Hyperthyroidism is the clinical state resulting from excessive secretion of thyroid hormones, thyroxine (TJ and tri-iodothyronine (Tg). This is one of the most common endocrine disorders in cats and humans.

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1991/12
Use of the triiodothyronine suppression test for diagnosis of hyperthyroidism in ill cats that have serum concentration of iodothyronines within normal range.
Concluded that the triiodothyronine suppression test is a safe and accurate test for diagnosis of hyperthyroidism in cats with suggestive clinical signs of the disease but lacking high serum concentration of iodothyronines.

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1991/12
Pharmacokinetics of Intravenous and Oral Methimazole Following Single- and Multiple-Dose Administration in Normal Cats
The pharmacokinetics of methimazole (MMI) administered intravenously and orally were determined in six adult domestic shorthaired cats.

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1991/12
An Assessment of the Cite T4 Immunoassay

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1991/09
Hyperthyroidism in Cats

HYPERTHYROIDISM is a common disease of older cats. I. Because of the apparent increased frequency of feline hyperthyroidism in recent years, practitioners should be familiar with the clinical presentation, diagnosis, and treatment of the disease. Feline hyperthyroidism results from excessive secretion of thyroid hormones. The disease is most often caused by a thyroid adenoma or adenomatous hyperplasia (approximately 98% of cats). Adenocarcinomas are present in 2% of affected cats and may metastasize. One or both lobes of the thyroid gland can be involved, and approximately 70% of cats have bilateral involvement.

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1991/06
Use of a Thyrotropin-Releasing Hormone (Trh) Stimulation Test as an Aid in the Diagnosis of Mild Hyperthyroidism in Cats

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1991/06
Thyroidectomy and Parathyroidectomy in the Dog and Cat

Thyroidectomy has become a fairly common surgical procedure in small animals because of the increasing incidence of thyroid tumors.

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1991/06
Radio-Iodine Treatment of Hyperthyroid Cats
Thirty-two elderly domestic shorthaired cats (mean age 12.9 years) were treated with radioiodine (131I). The dose of 131I administered ranged from 39 mBq to 134 mBq. Twenty-eight cats became euthyroid after treatment, one became hypothyroid and three remained hyperthyroxaemic. Two of the hyperthyroxaemic cats were successfully re-treated with 131I. Five cats died from concurrent diseases within one year of treatment. The administration of a dose of 131I selected by assessing the severity of the clinical signs, the size of the thyroid gland(s) and the serum level of thyroxine was an effective treatment for hyperthyroidism.

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1991/05
Thyroid scintigraphy in small animals

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1991/05
Inherited Primary Hypothyroidism with Thyrotrophin Resistance in Japanese Cats

The incidence of congenital hypothyroidism in man is reported to be 1 in 3684 live births, and most cases are due to primary hypothyroidism (Fisher, Dussault, Foley et al. 1979). Pedigree analyses have suggested genetic influences for such diseases.

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1991/04
Feline hyperthyroidism

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1991/01
Pharmacokinetics of Methimazole in Normal Cats and Cats with Hyperthyroidism
The intravenous and oral disposition of the antithyroid drug methimazole was determined in 10 clinically normal cats and nine cats with naturally occurring hyperthyroidism.

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1991/01
Heterogeneous Effects of Growth Factors and Serum on Tsh and Foskolin Stimulated Camp Levels in Continuous Cell Strains Derived from Feline Toxic Adenomatous Goiters

Hyperthyroidism is now the most common endocrine disease of the cat and, based on pathologic, immunologic and xenoptransplantation studies, appears similar to toxic nodular goiter. We have reported (Gerber et al, Proc Am Thyroid Assoc, 1989) on the proliferative response to growth factors of these cell lines. Insulin and IGF-1 stimulated growth in PETCAT-1 and PETCAT-2 cell lines but not in normal cells; EGF and serum stimulated all cell types. In this study, PETCAT-1 and PETCAT-2 cells were grown in 24-well plates in 6H media for 7 days, in 4H for 6 days and then in 4H +/- growth factor (50 ng/ml EGF, 5 ng/ml bFGF, 50 ng/ml IGF-1, 10% calf serum, 10ug/ml insulin or serum/insulin) for 3 days.

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1991/01
Effects of a-Retinoic Acid on Proliferation of Cat and Rat Thyroid Cell Lines in Vitro

Retinoids control cellular differentiation and proliferation; however, the effect appears to be extremely different depending on the tissue. There are only very few recent studies on the effects of retinoids on thyroid follicular cells in vitro (van Herle et al, JCEM 71: 755, 1990). For this reason we have investigated the growth effect of alpha-retinoic acid (RA) on proliferation of 6 thyroid cell lines from cats and rats.

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1991/01
Autonomous Growth and Function of Cultured Thyroid Follicles from Cats with Spontaneous Hyperthyroidism
Spontaneous feline hyperthyroidism is a unique experimental model of toxic nodular goiter. To determine whether feline toxic goiter is caused by extrathyroidal stimulating factors or by the intrinsic autonomy of follicular cells, primary cultures of enzymatically dissociated follicles from 15 hyperthyroid cat goiters and from 3 normal cat thyroid glands were embedded in collagen gels.

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1990/12
The use of antithyroid drugs in the medical management of feline hyperthyroidism
Antithyroid drugs are widely used in human medicine for the medical management of Graves' disease. Because patients with Graves' disease may undergo spontaneous remission, antithyroid drugs are preferred for long-term therapy because they do not permanently affect thyroid function. Hyperthyroidism in cats is somewhat different, in that spontaneous remission has not been reported and therefore ablative treatment (surgery or radioiodine) is often preferred.

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1990/12
Radioactive iodine therapy in feline hyperthyroidism

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1990/12
Diagnosis of Occult Hyperthyroidism in Cats
As expertise among small animal practitioners grows, feline hyperthyroidism is being diagnosed earlier in the course of the disease. There are, in fact, a growing number of cats with clinical signs of hyperthyroidism and palpably large thyroid glands whose serum total thyroxine (T4) and triiodothyronine (T3) concentrations are within the normal or borderline range. This condition can be referred to as "occult" hyperthyroidism. Early detection and treatment of feline hyperthyroidism presents an obvious advantage in avoiding some of the deleterious effects of chronic thyroid hormone excess (eg, cardiomyopathy).

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1990/11
In Search of a Cause for Feline Hyperthyroidism

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1990/11
Feline Hyperthyroidism

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1990/11
Effect of nonthyroidal illness on serum thyroxine concentrations in cats: 494 cases (1988)
We reviewed the medical records of 494 cats with a variety of nonthyroidal diseases in which serum thyroxine (T4) concentration was determined as part of diagnostic evaluation. The cats were grouped by category of disease (ie, renal disease, congestive heart failure, diabetes mellitus, focal neoplasia, systemic neoplasia, hepatopathy, inflammatory bowel disease, inflammatory pulmonary disease, miscellaneous diseases, or undiagnosed disease), degree of illness (ie, mild, moderate, or severe), survival (ie, lived, died, or euthanatized), and presence or absence of a palpable thyroid gland.

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1990/09
Triiodothyronine (T3) suppression test. An aid in the diagnosis of mild hyperthyroidism in cats
The purpose of this study was to develop a T3 suppression test to help in the diagnosis of mild hyperthyroidism in cats.

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1990/09
Serum thyroxine concentrations following fixed-dose radioactive iodine treatment in hyperthyroid cats : 62 cases [1986-1989]
The authors feel that radioactive iodine given at a fixed dose of 4 mCi/cat IV is an effective treatment for feline hyperthyroidism.

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1990/07
Recurrence of hyperthyroidism after thyroidectomy in cats
RECURRENCE OF HYPERTHYROIDISM occurred in 4/40 cats treated surgically by thyroidectomy. Regrowth of abnormal tissue at the site of the originally affected gland was found in 3/4.

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1990/04
Recurrence of Hyperthyroidism after Thyroidectomy in Cats

-Retrospective study of 48 hyperthyroid cats that underwent thyroidectomy over a 10 year period.

1990/03
Hypertension in cats with chronic renal failure or hyperthyroidism
The Doppler ultrasonic recording technique was used to measure systolic and diastolic blood pressures indirectly in 28 cats with naturally occurring renal failure, 39 cats with hyperthyroidism, and 33 clinically normal cats.

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1990/03
Glucose intolerance in spontaneous hyperthyroid cats

We have previously demonstrated an impairment of glucose tolerance in cats rendered hyperthyroid with a 4-week treatment of thyroxine (J. Endocrinol.121: 249-251, 1989). For the present study intravenous glucose tolerance tests (1.O g glucosekg body weight) were performed in 5 spontaneously hyperthyroid cats with T4 concentrations of 216 2 64.7 nmoVl (meanLSEM, normal: 28.8 & 6.0 nmol/l).

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1989/09
Occurrence of problems after three techniques of bilateral thyroidectomy in cats
The incidence of recurrence was significantly higher in cats treated with the intracapsular dissection technique than the modified intra- or extracapsular dissection techniques.

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1989/08
Horner's Syndrome in Dogs and Cats: 100 Cases (1975-1985)
The medical records of 74 dogs and 26 cats with Horner's syndrome (HS) that were admitted to the New York State College of Veterinary Medicine between January 1975 and October 1985 were reviewed. In dogs, but not cats, HS was associated significantly (P less than 0.01) with increasing age.

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1989/08
Evaluation of thyroid scintigraphy in small animals
Thyroid scintigraphy in rats and mice with 99mTc and 123I was attempted to examine whether this modality might be used in small animals and to describe the possibilities of its application in examining experimentally produced thyroid diseases.

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1989/07
Thyroidal Radioiodine Uptake in Hyperthyroid Cats
Thyroidal radioiodine uptake was measured in 10 healthy domestic cats and in 20 hyperthyroid cats.

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1989/06
Perspectives on the diagnosis of feline hyperthyroidism
It is felt that over time there has been a real increase in the incidence of this disease, not simply an increase due to diagnosticians' heightened awareness of hyperthyroidism.

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1989/05
Metabolic and endocrine myopathies of dogs and cats
Metabolic and endocrine myopathies are discussed including those associated with skeletal muscle storage diseases [glycogen storage diseases, muscle triglyceride storage diseases, and mitochondrial myopathies], malignant hyperthermia, exertional rhabdomyolysis, hyperthyroidism, hypothyroidism, hyperadrenocorticism, hypoadrenocorticism, primary aldosteronism [Conn's syndrome], Nelson's syndrome, hypopituitarism, hyposomatotropism, acromegaly, primary hyperparathyroidism, hypercalcemia, hypoparathyroidism, diabetes mellitus, hypokalemia, and hyperkalemia.

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1989/05
Impairment of Glucose Tolerance in Hyperthyroid Cats
Intravenous glucose tolerance tests were performed in eight adult cats before and after a 4-week treatment with thyroxine. It is concluded that hyperthyroidism in cats leads to impairment of glucose tolerance possibly due to peripheral insulin resistance.

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1989/05
Familial predisposition in feline hyperthyroidism
Thyrotoxicosis was diagnosed in three related cats, a female and her two male offspring, belonging to the same owner.

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1989/04
Treatment of Feline Hyperthyroidism

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1989/04
Relation of Endogenous Heinz Bodies to Disease and Anemia in Cats: 120 Cases (1978-1987)
Disease diagnosis, age, sex, and selected hematologic variables were evaluated retrospectively in a population of feline patients with high number of circulating Heinz bodies. By comparing these cats with a control population and results of additional hematologic investigation on a subsample of the cats, we tested the hypotheses that endogenous Heinz body formation is increased in specific disease states and that endogenous Heinz bodies may contribute to anemia. There was strong correlation between diabetes mellitus, hyperthyroidism, and lymphoma and Heinz body formation.

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1989/04
Feline Hypothyroidism

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1989/04
Effect of glucocorticoids on thyroid function in normal cats and cats with hyperthyroidism
A significant decrease in T4 levels occurred 24 hours post prednisone in the normal cats but not in the hyperthyroid cats. T4 levels were not significantly different than baseline levels at 1 and 2 weeks post methylprednisolone.

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1989/04
Antithyroid and Goitrogenic Effects of Millet: Role of C-Glycosylflavones
Pearl millet [Pennisetum millet (L.) leeke] is the main source of food energy for the rural poor in many areas of the semiarid tropics. Epidemiological evidence suggests that millet may play a role in the genesis of endemic goiter in these areas, and sparse experimental data in rats support this suspicion.

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1989/01

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1989/01
Recognizing the Clinical Features of Feline Hyperthyroidism

The syndrome of feline hypertyroidism, first recognized just 10 years ago, has become a very common disease in the aging cat population. Small-animal veterinarians can expect to regularly encounter cats suffering from this disorder.

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1989/01
Radioactive iodine treatment of a functional thyroid carcinoma producing hyperthyroidism in a dog

Radioactive iodine (131I) was used in the treatment of a 12-year-old female dog with hyperthyroidism resulting from a large, unresectable (and metastatic) thyroid carcinoma associated with signs of severe inspiratory stridor and dyspnea.

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1989/01
Lack of Thyroid Stimulatory Activity in the Serum of Hyperthyroid Cats

Hyperthyroidism, although common in Man, is relatively uncommon in other species. The only animal with an appreciable incidence of hyperthyroidism is the domestic cat. Benign thyroid swellings have long been recognised in the cat, but hyperthyroidism has only been described and characterised in recent years.

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1989/
Serum Free and Total Iodothyronine Concentrations in Normal Cats and Cats with Hyperthyroidism

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1988/11
Autoantibodies in feline hyperthyroidism
Thyroid autoantibodies have been demonstrated by indirect immunofluorescence in the sera of 10 of 29 (34 per cent) cats with hyperthyroidism.

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1988/08
Thyroid carcinoma causing hyperthyroidism in cats : 14 cases [1981-1986]
All cats treated with high dose radioiodine therapy became euthyroid following treatment.

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1988/08
ECG of the Month. Sinus Rhythm with Complete Heart Block.

A 10-year old castrated male domestic longhair cat with hyperthyroidism was referred for radioactive iodine (i-131) treatment. Treatment with methimazole was initiated 1 week before our examination.

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1988/07
Methimazole treatment of 262 cats with hyperthyroidism
Methimazole is shown to be an efficatious therapy for hyperthyroidism in the cat requiring at least daily treatment. Adverse effects developed in 18.3% of the cats treated, usually within the first month of treatment. Adverse reactions seen included anorexia, vomiting, lethargy, facial and neck excoriations, thrombocytopenia , and hepatopathy.

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1988/07
Altered Disposition of Propylthiouracil in Cats with Hyperthyroidism
The oral and intravenous disposition of the anti-thyroid drug propylthiouracil (PTU) was determined in six clinically healthy cats and four cats with naturally occurring hyperthyroidism.

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1988/06
Feline hyperthyroidism--a review
Feline hyperthyroidism is the name given to the multisystemic manifestation of excessive concentrations of circulating thyroid hormones, thyroxine (T4) and tri-iodothyronine (T3). The most common cause is a functional thyroid adenoma involving one or both thyroid lobes.

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1988/06
Feline Hyperthyroidism: A Descriptive and Case-Control Study

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1988/06
Echocardiographic findings in 103 cats with hyperthyroidism
Echocardiographic abnormalities of numerous types commonly occur in cats with hyperthyroidism but usually improve following a return to euthyroidism.

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1988/06
A multicompartmental model for iodide, thyroxine, and triiodothyronine metabolism in normal and spontaneously hyperthyroid cats
A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide (iodide*), T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats.

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1988/05
Dose-Dependent Induction of Anti-Native DNA Antibodies in Cats by Propylthiouracil
Cats receiving propylthiouracil (PTU) develop antinuclear antibodies (ANA) and an immune-mediated disease syndrome characterized by anorexia, lymphadenopathy, weight loss, and Coombs-positive hemolytic anemia. Investigation of the ANA specificity indicated that the predominant ANA activity consistent of anti-native DNA (nDNA) antibodies. The formation of anti-nDNA antibodies and immune-mediated disease syndrome appeared to be dose-dependent, even in cats in which a response had been induced on 4 prior occasions. These results supply further evidence that PTU-induced autoimmunity is not the result of a simple drug allergy. Rather, it appears that PTU induces a lupus-like syndrome, including the hallmark sign of systemic lupus erythematosus, anti-nDNA antibodies.

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1988/02
Predictive value of tracer studies for 131I Treatment in hyperthyroid cats
Tracer kinetics of radioiodine do not accurately predict post therapy radioiodine kinetics in many cats.

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1988/01
Serial determination of thyroxine concentrations in hyperthyroid cats
Although concentrations did vary, no significant variation in T4 levels was seen with time, and all T4 levels remained above normal during the study.

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1988/01
Assessing degree of hyperthyroidism in cats
Total T4 and T3 levels appear to correlate with the degree of hyperthyroidism in cats.

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1987/12
Facial Neuropathy in Dogs and Cats: 95 Cases (1975-1985)
.
The medical records of 79 dogs and 16 cats admitted to the New York State College of Veterinary Medicine between January 1975 and October 1985 with facial nerve dysfunction were reviewed.

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1987/11
Lack of Circulating Thyroid Stimulating Immunoglobulins in Cats with Hyperthyroidism
Although feline hyperthyroidism has become a commonly diagnosed disorder of older cats, the underlying etiology remains unknown.

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1987/10
Treatment of Feline Hyperthyroidism with Radioactive Iodine

Feline hyperthyroidism is a recently recognized syndrome of thyrotoxicosis primarily seen in older cats, and usually associated with thyroid adenomas. The purpose of the present study was to describe the treatment of feline hyperthyroidism using radioactive iodine (i-131) in 43 cases presented to the Texas A&M Univeristy Veterinary Teaching Hospital between June 1984 and September 1986.

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1987/09
Feline Thyroidectomy. A Comparison of Postoperative Hypocalcemia Associated with Three Different Surgical Techniques
Three bilateral thyroidectomy techniques used in 41 hyperthyroid cats over a 7 year period were compared for rates of postoperative hypocalcemia.

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1987/08
Peripheral metabolism of thyroid hormones and iodide in healthy and hyperthyroid cats
The metabolic clearance rate, volume of distribution, and fractional clearance rate of thyroxine (T4), triiodothyronine (T3), and iodide were calculated for 6 healthy and 7 hyperthyroid cats, using single-compartmental and noncompartmental methods of analysis.

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1987/08
Autonomy of Growth and of Iodine Metabolism in Hyperthyroid Feline Goiters Transplanted onto Nude Mice
Hyperthyroidism caused by nodular goiters is a common disease of aging cats. Growth and iodine metabolism were studied by autoradiography in normal and hyperfunctioning thyroid tissue obtained from cats injected with 125I before surgery, and in xenografts, grown in nude mice, after double-labeling with 131I and [3H]thymidine.

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1987/07
Serum thyroid hormone concentrations fluctuate in cats with hyperthyroidism
We measured serum thyroxine (T4) and 3,3',5-triiodothyronine (T3) concentrations in hyperthyroid cats (hourly for 10 hours in 14 cats, and daily for 15 days in seven cats) to assess fluctuation in thyroid hormone levels.

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1987/01
Results of Radioactive Iodine Therapy in 23 Cats with Hyperthyroidism
Twenty-three hyperthyroid cats were treated with a fixed 5 mCi dose of I-131. The use of I-131 appears to safe and effective treatment for feline hyperthyroidism.

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1987/01
Prenatal Development of the Cat Thyroid: Immunohistochemical Demonstration of Calcitonin in the "C" Cells

The presence of calcitonin in the cat thyroid was studied immunohistochemically in a series of gland development. The first positive cells are to be found on the 38th day of gestation, i.e. 1-2 days after level nine of ontogenetic development has been reached.

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1986/07
Feline Hyperthyroidism

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1986/07
Echocardiography, Electrocardiography, and Radiography of Cats with Dilatation Cardiomyopathy, Hypertrophic Cardiomyopathy, and Hyperthyroidism

The echocardiographic, ECG, and radiographic findings of sequentially examined cats with dilatation cardiomyopathy (DCM, n = 7), hypertrophic cardiomyopathy (HCM, n = 8), and hyperthyroidism (HT, n = 20) were compared with those of healthy control cats (n = 11).

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1986/07
Echocardiographic, Electrocardiographic, and Radiographic Detection of Cardiomegaly in Hyperthyroid Cats
Hyperthyroid cats were examined by electrocardiography, radiography, and echocardiography for the presence of cardiomegaly.

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1986/05
Serum thyroxine concentrations after radioactive iodine therapy in cats with hyperthyroidism
Thirty-one cats with hyperthyroidism were given one dose of radioactive iodine (131I) IV. Serum thyroxine (T4) concentrations were measured before treatment in all cats, at 12-hour intervals after treatment in 10 cats, and at 48-hour intervals after treatment in 21 cats.

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1986/04
Treatments for Hyperthyroidism

The specific cause(s) of feline hyperthyroidism is not known. Spontaneous remission, without the use of some type of medical or surgical treatment, docs not occur. Consequently. the aim of treatment for feline hyperthyroidism is to control the excessive or inappropriate secretion of th yroid hormones from the hyperfunctional thyroid glands (i.e. thyroid adcnomatous hyperplasia or adenoma). Interestingly. thyroid carcinoma as a cause of fcline hyperthyroidism occurs in only 1-2% of the reported cases.

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1986/01
Congestive Heart Failure Associated with Hyperthyroidism in Cats
Hyperthyroidism was diagnosed in 4 cats with congestive heart failure. Dyspnea and anorexia were observed in 3 of the 4 cats. In each cat, a holosystolic left and/or right apical heart murmur was auscultated. In 3 cats, a prominent extra heart sound (gallop rhythm) was auscultated. All cats had a palpably large thyroid lobe(s) and weight loss.

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1985/08
Feline Hyperthyroidism

Hyperthyroidism is a multisystemic disorder resulting from excessive circulating concentrations of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). Feline hyperthyroidism occurs in the middle- to old-aged cats. There is no breed or sex predilection. Functional thyroid adenoma (adenomatous hyperplasia) involving one or both thyroid lobes is the most common cause of feline hyperthyroidism.

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1985/07
An immune-mediated disease was produced in 9 of 17 (53%) normal healthy cats by daily p.o. administration of 150 mg of 6-propylthiouracil (PTU). This disease syndrome is characterized by lethargy, weight loss, lymphadenopathy, hemolytic anemia, a positive direct antiglobulin test (DAT) and antinuclear antibodies (ANA).

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1985/05
Pseudochylous Thoracic Effusion and Hyperthyroidism in a Cats

A 12-year-old castrated mixed-breed cat, with a severl-month history of polyphagia and occasional coughing, has dyspnea with abdominal breathing and an obvious mass on the ventral aspect of its neck.

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1985/04
Diagnosis and Treatment of Feline Hyperthyroidism

Hyperthyroidism (thyrotoxicosis) is a multisystemic disorder resulting from excessive circulating concentrations of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). Feline hyperthyroidism occurs in middle- to old-aged cats; there is no breed or sex predilection. Functional thyroid adenoma (adenomatous hyperplasia) involving one or both thyroid lobes is the most common cause of feline hyperthyroidism. Thyroid carcinoma, the primary cause of canine hyperthyroidism, rarely causes hyperthyroidism in the cat.

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1985/01
THE NORMAL FELINE THYROID
Technetium Pertechnetate Imaging and Determination of Thyroid to Salivary Gland Radioactivity Ratios in 10 Normal Cats
A technique for performing thyroid scintigrapy in the cat using technetium 99m pertechnetate is presented.

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1984/11
Selected Feline Endocrinopathies

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1984/11
Canine and Feline Thyroid Function Assessment with the Thyrotropin-Releasing Hormone Response Test
A canine and feline pituitary-thyroid function test based on thyrotropin-releasing hormone (TRH) stimulation of endogenous thyrotropin is described.

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1984/10
Surgical Treatment of Feline Hyperthyroidism. Results of 85 Cases

The use of thyroidectomy was evaluated as treatment in 85 cats with hyperthyroidism. Based on thyroid scan and surgical findings, 32 cats had a unilateral thyroidectomy, whereas 53 had bilateral thyroidectomy. Atrial and ventricular dysrhythmias developed in nine (10%) of the cats during surgery. Eight cats (9%) with severe hyperthyroidism died during or immediately after surgery.

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1984/09
Recurrent Peripheral Arteriovenous Fistula and Hyperthyroidism in a Cat
A 14-year-old domestic short-haired cat was examined for a recurrent arteriovenous fistula of the left elbow. Hyperthyroidism associated with multinodular adenomatous hyperplasia of the right thyroid gland was also diagnosed. Cardiovascular abnormalities associated with the vascular shunt and feline hyperthyroidism were noted. The delineation of the two concurrent diseases was based upon the results of a forelimb radiographic dye study, thyroid hormone assay, radionuclide scanning of the thyroid glands, and histopathologic evaluation of the excised right thyroid gland. The cat exhibited marked clinical improvement following amputation of the left foreleg and excision of the right thyroid gland. Six months later, the cat was euthanized following identification of an infiltrative sublingual squamous cell carcinoma.

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1984/07
Propylthiouracil-Associated Hemolytic Anemia, Thrombocytopenia, and Antinuclear Antibodies in Cats with Hyperthyroidism
Nine of 105 cats with hyperthyroidism treated with propylthiouracil developed a serious immune-mediated drug reaction during treatment. Adverse clinical signs, which developed after 19 to 37 days (mean, 24.8 days) of propylthiouracil administration, included lethargy, weakness, anorexia, and bleeding diathesis. Physical examination revealed pale mucous membranes, and petechial hemorrhages of the skin and oral cavity. Results of hematologic testing revealed severe anemia and thrombocytopenia. The direct antiglobulin (Coombs') test was positive in all 7 cats evaluated, whereas the serum antinuclear antibody titer was greater than or equal to 1:10 in 5 of the 8 cats tested. In 4 of the cats, treatment included appropriate supportive therapy and cessation of propylthiouracil; in these cats, anemia and thrombocytopenia resolved and Coombs' and antinuclear antibody tests became negative within 2 weeks.

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1984/07
Hypertropic Cardiomyopathy and Hyperthyroidism in the Cat

In a 21/2-year period, hypertrophic cardiomyopathy was found at necropsy of 23 cats that died (13 cats) or were euthanatized (10) because of problems associated with hyperthyroidism. Of these, 4 (17%) also had evidence of cardiac failure (pulmonary edema or pleural effusion).

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1984/07
Feline hyperthyroidism

Hyperthyroidism is a disorder resulting froln excessive circulating concentrations of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). Normally, circulating concentrations of these hormones lie within a narrow range; increased production and sustained high concentrations ofT4 and T3, circulated in excessive amounts to all body tissues cause the clinical and biochemical state of hyperthyroidism. Thyroid horlnones act in many tissues, and hyperthyroidism can produce abnorlnalities involving virtually every organ system.

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1984/06
Autoantibodies in feline hyperthyroidism

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1984/03
Radioactive iodine therapy in cats with hyperthyroidism
Eleven cats with hyperthyroidism were treated with radioactive iodine (131I). Previous unsuccessful treatments for hyperthyroidism included hemithyroidectomy (2 cats) and an antithyroid drug (7 cats).

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1984/01
RADIONUCLIDE THYROID IMAGING IN 135 CATS WITH HYPERTHYROIDISM
Thyroid scanning was performed in 135 hyperthyroid cats and 13 normal cats with technetium- 99m as pertechnetate (99mTc04) or with radioactive iodine (131I).

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1983/10
Spontaneous Hyperthyroidism in the Cat: An Animal Model for Toxic Nodular Goiter

In 150 aged cats with spontaneous hyperthyroidism, the most frequent clinical signs included weight loss, polyphagia, irritability, tachycardia, polyuria, and diarrhea.

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1983/08
Hyperthyroidism in Cats
Hyperthyroidism in cats can be caused by tumors (often malignant) or cranial mediastinal accessory thyroid tissue. Middle-aged cats with insidious onset of hyperactivity, rough haircoat, weight loss, polyphagia, polyuria and polydipsia are suspect. A bilateral cervical swelling between the larynx and thoracic inlet and ECG abnormalities may be seen. Normal feline thyroid h9rmone levels have not been established and fluctuate with time of day, age. breed, pregnancy status and use of various drugs. Elevated SGOT, SGPT and serum alkaline phosphatase levels may occur. Thyroidectomy is the best treatment but propylthiouracil can be used. Postoperative complications include hypothyroidism, hypoparathyroidism, recurrent laryngeal nerve damage and recurrence of hyperthyroidism.

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1983/07
Radioactive Iodine Treatment of Feline Hyperthyroidism

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1983/07
Feline hyperthyroidism: pretreatment clinical and laboratory evaluation of 131 cases
Hyperthyroidism was diagnosed in 131 cats during a 3 1/2-year period. The cats ranged in age from 6 to 20 years; there was no breed or sex predilection. The most frequent clinical signs included weight loss, polyphagia, increased activity, polydipsia, polyuria, and vomiting.

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1983/07
Assessment of Thyroid Functional Reserve in the Cat by the Thyrotropin-Stimulation Test
Serum thyroxine (T4) concentrations before and after various IV doses of bovine thyrotropin (TSH) were measured over a 48-hour period in 19 healthy cats.

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1983/05
An Adenoma in Ectopic Thyroid Tissue Causing Hyperthyroidism in a Cat

Hyperthyroidism is the clinical syndrome that results from hypersecretion of the thyroid hormones, thyroxine (T4) and/or triiodothyronine (T3). The wide variety of biochemical abnormalities seen in cats with this disease demonstrates the multisystemic nature of this clinical state in which cardiac, hepatic, gastrointestinal and renal manifestations are commonly seen.

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1982/12
Treatment of Canine and Feline Hypoparathyroidism

Vitamin D and Parathyroid hormone play important roles in maintaining normal circulating concen- trations of calcium and phosphorus. Vitamin D is obtained from dietary sources and produced endoge- nously from precursors in the skin. Ultraviolet irra- diation ofergosterol, a sterol found in certain plants, produces vitamin D, (ergocalciferol). In the skin, ultraviolet light converts 7-dehydrocholesterol, a by- product in the synthesis of cholesterol, to vitamin D, (cholecalciferol).

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1982/10
Diagnosis and Treatment of Feline Hyperthyroidism

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1982/04
Electrocardiographic Findings in 45 Cats with Hyperthyroidism
Electrocardiographic (ECG) abnormalities were recorded in 36 (80%) of 45 cats with untreated hyperthyroidism caused by hyperfunctioning thyroid adenomas (adenomatous hyperplasia).

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1982/01
Toxic nodular goitre in the cat

Hyperthyroidism was diagnosed in 24 aged cats and was characterized by palpable enlargement of the thyroid gland, high circulating levels of thyroid hormones, increased thyroidal uptake of '',I, and abnormal uptake and distribution of activity on thyroid scintiscans. Unilateral or bilateral thyroidectomy was performed in all cats and resulted in remission of signs in all but one case. The histological diagnosis was adenomatous hyperplasia in 23 cats and adenocarcinoma in one. Serum thyroid hormone concentrations decreased to normal or subnormal levels within 24 hours after complete removal of functioning thyroid nodules. Hypothyroidism occurred postoperatively in 16 of the 24 cats. Presumed hypopara- thyroidism and hypocalcaemia occurred in 6 cases.

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1981/09
Treatment of Four Cases: Feline Hyperthyroidism
The following four cases Illustrate the major methods of treatment of feline hyperthyroidism and provide some Insight Into possible sequelae. They are not, however, Intended to provide definitive conclusions regarding the treatment. Determination of the treatment of choice awaits further understanding of the disease and controlled therapeutic studies.
1981/09
Propylthiouracil in the treatment of feline hyperthyroidism

Hyperthyroidism is the result of excessive production of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). In the cat, hyperthyroidism usually results from one or more functional ade- nomas that involve one or both thyroId" lobes; thyroid carcinomas rarely cause feline.

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1981/07
Weight Loss in Cats Which Eat Well

Four cats were investigated because they lost weight while eating well. One cat was found to have hypoinsulinaemic diabetes mellitus, and another had maldigestion caused by exocrine pancreatic atrophy.

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1981/05
Hyperthyroidism in an Aged Cat
1980/08
Unilateral Thyroid Neoplasm in a Cat
An aged cat with a thyroid neoplasm showed clinical signs and had laboratory data and post mortem findings similar to those observed in human and canine patients afflicted with hyperthyroidism. Because of these similarities hyperthyroidism was suspected in the cat.

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1980/07
Feline hyperthyroidism: further definition.
Spontaneous hyperthyroidism resulting from toxic nodular goiter was studied in 28 cats aged 9-18 years.

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1980/04
Ecg of the Month: Hyperthyroidism in a Cat

A l3-year-old male castrated domestic short-haired cat was presented for examination because of nervous- ness, weight loss, polyphagia, voluminous feces, and shortness of breath. On examination, the cat was active, but emaciated.

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1980/02
Hyperthyroidism in the cat: ten cases
In ten neutered crossbred cats 10 to 14 years old and of both sexes, hyperthyroidism was evidenced by hyperactivity, weight loss despite increased appetite, frequent defecation with bulky stools, thirst, polyuria, moderately elevated temperature, increased heart rate and size, sometimes with murmurs and arrhythmias, and palpable enlargement of one or both thyroid lobes.

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1979/09
Feline anaplastic giant cell adenocarcinoma of the thyroid.
An 8-year-old castrated, male, domestic short-haired cat had anaplastic giant cell adenocarcinoma in the thyroid gland. The cat had difficulty in breathing and swallowing because of a rapidly growing mass in the left thyroid region that partially enclosed the trachea and esophagus and had evidence of diffuse discrete interstitial pulmonary metastases.

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1979/07
Spontaneous hyperthyroidism in the cat.

Spontaneous hyperthyroidism due to functional thyroid adenomas was diagnosed in 5 cats ranging in age from 11 to 15 years. Clinical signs included weight loss, polyphagia. hyperdefecation, hyperactivity, and tachycardia.

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1978/
Thyroxine and triiodothyronine assays were performed on ten animals from ten different species to establish standard values. These values can now be of clinical use to assess thyroid function.

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1976/04
Adenomas and carcinomas of the canine and feline thyroid.

NEOPLASMIS OF THE HUMNAN- THYROID are a well-studied clinical and pathologic entity. Numerous publications have dealt with their histo- logic classification and biology. Comparable data concerning thyroid neo- plasms in dogs and cats has not been well established, although these tumors have been described in several textbooks and monographs.

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1974/09
Serum thyroxine (T-4) and triiodothyronine (T-3) uptake values in normal adult cats.

Values for serum T4 by competitive protein binding and for T3 uptake by silicate particle absorption were determined in normal adult cats.

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1974/07
Hypothyroidism

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1973/11
Thyroid function tests in domesticated animals: free thyroxine index.

Normal values for resin sponge uptake of labeled 3,5,3 triiodothyronine (T-3) (T-3 test), total serum thyroxine (T-4) by competitive protein binding (T4 test) free thyroxine index (FTI), a product of T-3 and T4 test results (T-7 test), were determined as a function of age in 7 species of domesticated animals.

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1973/01
The Thyroid Gland--a Review

Diseases of the thyroid have been known for many thousands of years, having been recorded by the Ancient Chinese, and epidemic goitre still affects an estimated 200 million people. Most of the notorious endemic goitre areas are located in high mountain regions and certain low lying areas that were subject to flooding and glaciation during the last Ice Age. In many of these areas, where endemic goitre occurs in man, goitre has also been reported in domestic animals (Kelly and Sneddon 1960).

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1971/05
Some Conditions Seen in Feline Practice Attributable to Hormonal Causes

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1970/06
Thyroid Function in Domestic Animals

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1970/04
Adenocarcinoma of the thyroid gland in a cat.

THE NUMBER of reports documenting the occurrence of thyroid adenocarcinoma in the cat are relatively few. A thyroid carcinoma in a 15-year-old castrated male domestic shorthair cat has· been reported. A suryey of thyroid disease occurring in dogs and cats necropsied at Angell Memorial Animal Hospital during a 6-month period, and from selected cases of thyroid disease collected over a lO-year period, revealed 4 cases ,of thyroid adenocarcinoma in the cat.

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1966/05
Cyclic Fluctuations in I-131 Content of Thyroid Glands of Cats and Monkeys

Diurnal cycles have been reported in various pituitary-target organ relationships.

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1964/08
An Histological Study of Thyroid Abnormalities in the Domestic Cat
The thyroid gland in seventy-five cats has been examined. Abnormalities are by no means uncommon and cases of adenomas, adenomatous goitre, colloid goitre, carcinoma and amyloidosis are described.

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1961/10
Normal Thyroid Function and Response to Hemithyroidectomy in the Cat

A program of study dealing with neural regulation of thyroid function is being carried out in our laboratory (Knigge and Bierman, '58; Knigge, '60a, '60b, '61: Florsheim and Knigge, '61). One aspect of these studies deals with the role of the central nervous system in compensatory thyroid responses to hemithyroidectomy of the cat.

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1958/01
The Clinico-Pathological Aspect of Thyroid Disease in the Dog and Cat

In Part I the gross- and histologic lesions in the thyroid of dogs and cats encounted at the Angell Memorial Hospital were reviewed. Patholic alterations were observed to occur more frequently than has been previously realized.

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1955/10
Arterial Thrombosis and Thyroid Carcinoma in a Cat

On 15 Sep 1954 a 15-year-old castrated male tabby was admitted at the Angell Memorial Hospital in acute distress. It had been resting quietly shortly before, when it suddenly got up, crying out and with the left foreleg dragging. On examination the cat was seen to be exceedingly obese (18 pounds), with sparse, brittle hair over the flanks and very flabby, atonic muscles.

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