Okamoto K, Yamaguchi H, Hirai S, Shoji M, Inoue K, Takatama M
Department of Neurology, Gunma University School of Medicine, Japan.
Prog Clin Biol Res. 1989;317:953-63.
Both light and immunogold electron microscopy revealed that beta protein is closely associated with cerebrovascular and senile plaque amyloid. Diffuse (very primitive) plaques of the cerebral cortex and cerebellum in subjects with senile dementia of the Alzheimer type (SDAT) were seen as ill-defined areas of the fine fibrillar materials labeled by beta protein immunostain and silver impregnation. Electron and immunogold electron microscopic investigation revealed that cerebral diffuse plaques consist of accumulations of small bundles of amyloid fibrils scattered among the normal-looking neurites including a few altered neurites. The cell process membranes just adjacent to amyloid fibrils were frequently missing. Cerebellar diffuse plaques had structures similar to cerebral diffuse plaques, with two qualifications. First, the former had more altered neurites, and second, enlarged neurites contained mainly dense bodies and abnormally dense mitochondria lacking filamentous materials. In conclusion, cerebral diffuse plaques, which are the main plaques in SDAT, consist chiefly of amyloid fibrils interspersed among a majority of normal-looking neurites and a minority of altered neurites. This suggests the importance of amyloid deposition in the genesis of senile plaques.
光学显微镜和免疫金电子显微镜检查均显示，β蛋白与脑血管及老年斑淀粉样蛋白密切相关。在阿尔茨海默型老年痴呆（SDAT）患者的大脑皮质和小脑中，弥漫性（非常原始）斑块被视为β蛋白免疫染色和银浸染标记的细纤维物质的边界不清区域。电子显微镜和免疫金电子显微镜研究显示，大脑弥漫性斑块由散在分布于包括一些改变的神经突在内的外观正常的神经突中的小束淀粉样纤维聚集物组成。紧邻淀粉样纤维的细胞突膜常常缺失。小脑弥漫性斑块具有与大脑弥漫性斑块相似的结构，但有两点不同。第一，前者有更多改变的神经突；第二，增大的神经突主要含有致密小体和缺乏丝状物质的异常致密线粒体。总之，大脑弥漫性斑块是SDAT中的主要斑块，主要由散布于大多数外观正常的神经突和少数改变的神经突之间的淀粉样纤维组成。这表明淀粉样蛋白沉积在老年斑形成过程中的重要性。
