부산대학교 도서관

Light microscopic and ultrastructural changes and morphogenesis of intracerebral arteriosclerotic lesions were studied in autopsy cases. The lesions included were not only arteriosclerosis itself but also miscellaneous arterial changes which might stimulate cell proliferation and fibrosis in the intima resulting in arteriosclerosis.Cellulofibrous intimal thickening occurred predominantly at bifurcations of the intracerebral arteries more than 150μ in diameter in aged and hypertensive patients. Elastin and collagen were formed in the basement membrane (BM)-like substance in the subendothelial tissue and also around intimal smooth muscle cells, particularly markedly in the latter in the deep intima. Collagen replaced the BM-like substance which seemed to be used as a material for collagen formation.There are two kinds of atherosclerosis depending upon the atherogenesis, that is, fiber disintegration type and cell disintegration type. In the intracerebral arteries the latter was more common than the former. Various sized arteries down to 60μ in diameter were involved in the latter atherosclerosis.The accumulation of foam cells or ceroid in the intima with neither intimal cell proliferation nor fibrosis was designated as intimal lipoidosis in this paper. The lesions were found in small arteries less than 150μ in diameter, sometimes encountered in ones as small as 50μ. Foam cells in the lesions were presumably derived from circulating monocytes. Ceroid occurred microscopically in the whole intima as rims of acid fast material surrounding large fat globules. The vascular ceroid in the brains retained the similar staining properties to the ceroid in liver cells. It was disclosed electron microscopically as a wavy laminated structure with a fingerprint pattern having an electron-dense osmiophilic layer of about 70Å thick alternating with an electron lucent layer about 100Å thick.The arteries involved in intimal edema had several layered myointimal cells just beneath the endothelial lining. It was strongly suggested that the myointimal cells could be derived from the endothelial cells, because of having similar ultrastructures to them.Pseudocalcification was observed in and about small blood vessels of the globus pallidus. Electron microscopic studies revealed that dense granular substances, consisting of phosphorus, calcium, iron, and sometimes magnesium were deposited in necrosed smooth muscle cells and in BM-like substance increased around the smooth muscle cells in the media.Infrequent cases had meningeal and cortical arteries involved in amyloidosis. Intracerebral microaneurysms which were the direct cause of hypertensive intracerebral hemorrhage were formed on degenerated arterial segments with amyloidosis in a few cases.In large microaneurysms over 350μ in diameter, thrombosis was frequently formed in their lumina. Organization of the thrombi was brought about by endothelial proliferation on the surface of the thrombi and by new capillary formation in the thrombi from the surface. Intimal cells, which were presumably derived from endothelial cells, and BM-like substance appeared beneath the endothelium. Fibrous nodular arterial lesions were completely organized microaneurysms with occluded thrombi.