Thesis--Wisconsin. / Includes bibliographical references (leaves 87-96).

Thesis--University of Wisconsin--Madison. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 102-110).

Zugl.: Habil'schrift Bern.

Background: Because of the vague clinical signs and limitations of thyroid function tests, misdiagnosis of hypothyroidism in dogs is common and leads to inappropriate treatment with levothyroxine. Chronic supplementation can suppress the hypothalamic-pituitary-thyroid axis (HPTA) and make it difficult to assess thyroid function following withdrawal of levothyroxine. Objectives: To determine if the HPTA is suppressed following levothyroxine administration in euthyroid dogs and the time required for resolution of any suppression. Animals: Twenty-eight healthy euthyroid dogs Methods: A prospective randomized study administering levothyroxine to euthyroid dogs with levothyroxine, for either 8 weeks (group 1) or 16 weeks (group 2). Serum concentrations of total thyroxine (T4), free thyroxine (fT4) by equilibrium dialysis, thyrotropin (TSH), and 3,5,3'-triiodothyronine (T3) were measured every 4 weeks during supplementation and for 16 weeks after levothyroxine was discontinued. Results: Mean serum T4 and fT4 were significantly higher and TSH was lower in all dogs during levothyroxine administration compared to baseline. Mean serum concentrations of T4 and fT4 in both groups and TSH in group 1, beginning 1 week after levothyroxine was discontinued, were significantly different compared to values during levothyroxine administration but not compared to baseline values. Conclusions and Clinical Importance: Suppression of the HPTA occurred during levothyroxine supplementation and mean serum T4, fT4 and TSH concentrations were not significantly different compared to baseline 1 week after discontinuation in both groups. Assessing thyroid function tests 1 week after cessation of levothyroxine will likely provide an accurate assessment of thyroid function in euthyroid dogs. / Master of Science

published_or_final_version / Medicine / Master / Master of Philosophy

No description available.

No description available.

Dissertation submitted to the Faculty of Dentistry, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Dentistry. / Growth and development of the skull is influenced by metabolic factors such as the endocrinopathies. The purpose of this study is to examine the effects of induced hypothyroidism on growth and development of the skull of the Vervet monkey. Seven infant monkeys of the subspecies Ceraop-ithecus aethiops cloetei were selected as the experimental animals in this study. Two of the seven monkeys were used as the control group, the remaining five monkeys were given radio-active iodine to depress their thyroid activity. Cephalometric records were taken of the animals for a period of approximately one year, at the end of which time they were sacrificed. At the age of 15 months the radiographs of the hypothyroidic monkeys, when compared to those of the control group, exhibit marked differences in cranial form. However, the most marked changes are seen in the cranial vaults of the experimental animals. Some of the findings are examined in the light of a number of theories which have been proposed for the control of the growth and development of the skull. / WHSLYP2017

Thesis (M.A.)--University of Wisconsin-Madison, 1972. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 42-45).

Thesis (M. Phil.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 92-112).