ENZYME HISTOCHEMICAL STUDIES OF SENILE PLAQUES AND PLAQUE-LIKE DEGENERATION OF ARTERIES AND CAPILLARIES (SCHOLZ)

Enzyme histochemical studies, of senile plaques and the plaque-like degeneration of arteries and capillaries (Scholz), were carried out on four brains of patients senile dementia. The NAD-diaphorese activity of the plaques increased, especially in their peripheral zones whereas the central cores showed no enzyme activity. The acid phosphatase activity of senile plaques increased markedly throughout. NAD-d and acid-ph activity in glia cells in the surrounding tissue of the plaques increased markedly. The plaques with a few exceptions showed no acetylcholinesterase activity. The plaque-like degeneration of arteries and capillaries like the central cores of plaques generally showed no NAD-d activity. Acid-ph activity in the degenerated arteries was very weak, suggesting independent amyloid deposition there. Similarity of electronmicroscopic structural and enzymatic findings in the plaques and in Wallerian degeneration (Suzuki and Terry, 1967) and the independent deposition of amyloid in the plaque-like degenerated arteries in the brain, as well as in those of internal organs, suggest that the plaques are formed by severance of neuronal continuity, by the deposition of amyloid, and that amyloid deposition is important in the pathogenesis of senile dementia. © 1969 Springer-Verlag.