Production of ulcerated atherosclerotic lesions in cockerels.

• Atherosclerosis, the lipid-containing intimal lesion with marked fibrosis and calcification, morphologically similar to the human lesion, has been produced consistently in numerous animal species, mostly by feeding diets high in cholesterol and fat, with and without hormonal or other dietary manipulations. However, ulceration and thrombosis, the so-called "complicated" lesions so frequent in human atherosclerosis and so important in leading to morbidity and mortality, have not been predictably reproduced in animals prior to our own studies presented in preliminary fashion in 1958." Spontaneous ulceration of abdominal aorta lesions in old pigeons was described by Clarkson et al. Wakerlin, in 1951, described ulceration and thrombosis occurring in atherosclerotic lesions in hypertensive dogs on a high-cholesterol, high-fat diet with thiouracil.' Constantinides, in 1961," produced ulcerated aortic and coronary lesions with thrombosis in rabbits fed a highcholesterol, high-fat diet for two two-month periods alternating with three-month periods of normal, noncholesterol-containing diets and given high doses of vitamin A, Russell's viper venom, and norepinephrine just before they were sacrificed. The iiicidence of ulceration