Light and Electron Microscopic Observations of Diffuse Plaque and Its Related Conditions
Many ultrastructural studies appear to have confirmed the fine structures of senile plaques(SPs). SPs have been usually classified into three types:l)typical plaques with amyloid cores surrounded by degenerate neurites, 2)primitive plaques composed of many degenerate neurites and a few amyloid wisps,and 3)compact plaques consisting of a mass of amyloid without pathological neurites.Recent advances in staining methods such as f-protein immuno -histochemistry and the modified periodic-acid methenamine silver (PAM) method’ have offered important information concerning amyloid substance. In the present study, diffuse plaques(DPs)’,a type of SP,were investigated light and electron microscopically using various staining methods including modified-PAM electron microscopy3.Ultrastructural findings characteristically seen in DPs were similar to those obtained in the superficial layer of the cerebral cortex and occasionally in peripheral coronas of typical SPs. Based on these observations we discuss the morphological origin of SP amyloid.
KeywordsSenile Plaque Diffuse Plaque Amyloid Structure Silver Granule Cerebral Amyloid Deposit
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