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Feline Thyroid Center in Queenstown, Maryland. A one-page Guidelines at a Glance document is also available for download and is organized with a “3/2/1” approach: Three main takeaways, two specific actions, and one important reminder for veterinary

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lymph node metastasis in canine thyroid carcinoma,” University of Missouri. AAHSD005432: “Lattice SBRT for palliation of large tumors,” University of Missouri. AAHSD005433: “Calcium electroporation in dogs with measurable cutaneous cancer

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failure . J Am Vet Med Assoc 2003 ; 222 : 322 – 329 . 10.2460/javma.2003.222.322 2 Panciera DL . Cardiovascular complications of thyroid disease . In: Bonagura JD , ed. Kirk's current veterinary therapy XIII— small animal practice

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in American Journal of Veterinary Research

conducted to evaluate extrinsic factors relating to pharyngeal stability, but it is known that resection of the thyrohyoideus muscles leads to exercise-induced DDSP in some horses. 1 The thyrohyoideus muscle extends from the thyroid cartilage to the

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in American Journal of Veterinary Research

, lipase, bicarbonate, anion gap, thyroid (T4), bile acids, uric acid, and triglycerides. Because of the nature of the study, only renal-focused values were assessed and reported. Plasma SDMA concentrations were measured using 2 assays: the gold standard

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in American Journal of Veterinary Research

Abstract

Objective

To determine the effect of leptospirosis on thyroid hormone induction of the specific activity of hepatic microsomal glucose-6-phosphatase in laboratory rats.

Animals

Male Fisher 344 rats, 6 and 24 months old, healthy and infected with leptospirosis.

Procedure

The maximal velocity of glucose-6- phosphatase in intact and detergent-disrupted hepatic microsomes was assayed in duplicate or triplicate at 5 substrate concentrations, by monitoring the release of inorganic phosphate at 0-, 5-, and 10-minute intervals. The method of least squares was used to determine the velocity of the reactions. The level of statistical significance was determined, using the Student's t-test for unpaired data. Thyroid hormone (40 µg of T3/100 g of body weight) was administered for 5 consecutive days prior to sacrifice.

Results

Leptospirosis significantly increased the specific activity of the translocase component of glucose-6-phosphatase in old, but not young, rats. The activity of the translocase increased more than threefold in untreated, infected old animals, compared with untreated, healthy old animals. Thyroid hormone induced a two- and threefold increase in the specific activities of the translocase in young and old healthy animals, respectively. Thyroid hormone did not increase the activity of the translocase in old animals infected with leptospirosis.

Conclusions and Clinical Relevance

Leptospirosis alters the specific activity and induction by thyroid hormone of the translocase component of hepatic microsomal glucose-6-phosphatase in old male Fisher 344 rats. It is necessary to be aware of possible alterations in hepatic membrane-bound enzymes after leptospiral infection of older laboratory animals. (Am J Vet Res 1997;58:143–145)

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in American Journal of Veterinary Research

Abstract

Objective—To determine effects of athletic conditioning on thyroid hormone concentrations in a population of healthy sled dogs.

Animals—19 healthy adult sled dogs.

Procedure—Serum concentrations of thyroxine (T4), triiodothyronine (T3), thyroid-stimulating hormone (TSH), free T4 (fT4), free T3 (fT3), and autoantibodies directed against T3, T4, and thyroglobulin were measured in sled dogs that were not in training (ie, nonracing season) and again after dogs had been training at maximum athletic potential for 4 months.

Results—Analysis revealed significant decreases in T4 and fT4 concentrations and a significant increase in TSH concentration for dogs in the peak training state, compared with concentrations for dogs in the untrained state. Serum concentrations of T4 and fT4 were less than established reference ranges during the peak training state for 11 of 19 and 8 of 19 dogs, respectively; fT4 concentration was greater than the established reference range in 9 of 19 dogs in the untrained state.

Conclusions and Clinical Relevance—Decreased total T4 and fT4 concentrations and increased serum concentrations of TSH were consistently measured during the peak training state in healthy sled dogs, compared with concentrations determined during the untrained state. Although thyroid hormone concentrations remained within the established reference ranges in many of the dogs, values that were outside the reference range in some dogs could potentially lead to an incorrect assessment of thyroid status. Endurance training has a profound impact on the thyroid hormone concentrations of competitive sled dogs. ( Am J Vet Res 2004;65:333–337)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether expression of G proteins (Gi and Gs) is altered in thyroid gland adenomas obtained from hyperthyroid cats.

Sample Population—Adenomatous thyroid glands obtained from 8 hyperthyroid cats and thyroid glands obtained from 4 age-matched euthyroid cats.

Procedure—Expression of Gi and Gs was quantified in enriched membrane preparations of thyroid gland tissue, using immunoblotting with Gi and Gs antibodies and toxin-catalyzed ADP-ribosylation.

Results—Expression of Gi was significantly reduced in thyroid gland adenomas from hyperthyroid cats, compared with normal thyroid gland tissue from euthyroid cats. Expression of Gs was similar between the 2 groups.

Conclusions and Clinical Relevance—A decrease in expression of Gi in adenomatous thyroid glands of cats may reduce the negative inhibition of the cAMP cascade in thyroid cells, leading to autonomous growth and hypersecretion of thyroxine. Understanding the molecular mechanisms for hyperthyroidism in cats may lead to better treatment or, ultimately, prevention of the disease. (Am J Vet Res 2000;61:874–879)

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in American Journal of Veterinary Research

Summary

Changes in platelet indices (platelet count and platelet size) and pcv associated with thyroid disease were studied in 7 dogs with hypothyroidism and 21 cats with hyperthyroidism that were admitted to the veterinary teaching hospital. Compared with control (euthyroid) dogs, dogs with hypothyroidism had higher platelet count (P = 0.003), smaller platelet size (P = 0.01), and lower pcv (P = 0.02). Comparison of the group of hyperthyroid cats with a group of similarly aged, clinically normal cats with normal thyroxine values indicated that the group of hyperthyroid cats had significantly (P = 0.03) higher mean platelet size than did control cats, but differences were not found in mean platelet count or pcv. Results of this investigation indicate that the changes in platelet size reported in human beings with thyroid endocrinopathies also are found in animals so-affected. Although the pathogenesis of platelet abnormalities in animals with thyroid derangement is unclear and likely is multifactorial, the observed relation between platelet and erythrocyte production in this group of dogs is consistent with reports of an inverse relation between thrombocytopoiesis and erythropoiesis in iatrogenically hyperthyroid mice and in mice exposed to hypoxia.

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in American Journal of Veterinary Research

neural development, it was recently reported that the gene is downregulated in HIV encephalitis. 56–58 The transthyretin gene encodes for transthyretin protein, which is involved in thyroid hormone and retinal protein transport. The protein is primarily

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in American Journal of Veterinary Research