Abstract
Of ten lambs that were thyroidectomized early in life, five showed marked lesions. The others were either operated on too late in life or were too young at the time of death. The duration varied from 8 months 4 days to 2 years 5 months after the removal of the thyroids. The lesions were subcutaneous and subserous edema with, in most cases, ascites and hydrothorax. The kidneys showed parenchymatous nephritis with hyaline casts in the collecting tubules. The most striking changes were in the thoracic and abdominal aortse, and in the pulmonary arteries. These showed hyaline degeneration and calcification of the media in the form of placques. These were separated by thickened areas containing numerous fibroblasts and devoid of elastic fibres. Some of the smaller vessels near the aorta showed proliferation of the intima. There was a striking absence of fatty degeneration in any of the vessels. The controls, usually twin lambs of the same sex, did not show any of these tissue changes.
Scholz (1906) describes general edema and the kidney lesions in human cretins, without mentioning the aorta or pulmonary arteries.
Von Eiselsberg (1895) describes the changes in thyroidectomized sheep as being calcification of the intima without fat.
Experimentally, arteriosclerosis is generally produced on a mechanical basis. In this case it seems to be more of a chemical nature, perhaps due to senile changes occurring early in life as a result of complete thyroidectomy.
(The expenses of this research were defrayed by a grant from the Heckscher Foundation of Cornell University.)
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