[Neuropathological aspects of normal and abnormal aging]

Several senile changes in the central nervous system in cadavers were examined. The pattern of extension of Alzheimer's neurofibrillary tangles (NFT) and senile plaques (SP) in the olfactory bulbs of 100 specimens was examined during routine autopsy by immunohistochemical staining. NFT were first observed in the anterior olfactory nucleus after the age of 60, and incidence rose with increasing age. Senile plaques were found in the nucleus when there were many SP in the cerebral cortex. Of 25 non-demented amyotrophic lateral sclerosis patients, SP were found in the cerebral cortices of 10, and 9 of 10 were over 60 years old. NFT were observed in almost all patients over 60 years of age, but the incidence was low. Many ubiquitin-positive small-sized granules were observed in the second and third layer of the parahippocampal gyrus of aged patients, and the incidence rose with increasing age. On the other hand, few of these granules were in patients with Alzheimer's type dementia. Granulovacuolar degeneration was examined. Many centrally-located granules were positive for ubiquitin. Based on electron microscopic observation of these granules at several stages, the granules were thought to be a type of autophagosome. During the first stage of granulovacuolar degeneration, electron-dense materials appeared in the cytoplasm, following which they were surrounded by smooth endoplasmic reticulum. Analytical electron microscopy disclosed that the granules contained some aluminium.