On the Hirano bodies observed in the brains of the aged

Report 1

Abstract

On the Ammon horn from 100 autopsied brains of the aged, an investigation about the Hirano bodies (eosinophilic rod-like structure) was performed by the methods of conventional histology, histochemistry and electron microscopy for the formalin-fixed material, including the tilting method (top-entry type, BLG, of JEM 100B elecron microscope).
The results were as follows:
(1) Hirano bodies were observed in the nerve cell cytoplasm or neuropil of the pyramidal layer of Sommer sector. They were found in 46% of the examined cases and appeared parallel with increasing age.
(2) They were observed frequently together with other senile changes, such as Alzheimer neurofibrillary tangles, granulovacuolar degeneration and senile plaques.
(3) Cases with severe dementia showed abundant Hirano bodies. These had no relationship with other basic diseases of the patients.
(4) Histologically Hirano bodies were eosinophilic, stained red by Masson-trichrome, black by phosphotungustic acid hematoxylin and showed no argentophilia. They were positive with protein, weak positive with lipid and negative with carbohydrate and mucopolysac charide reactions.
(5) Electron microscopically Hirano bodies were composed of regularly arraged cross-lattice of 100Å filaments as a basic structure, which appeared as beaded filaments, lattice or sheets, according to the angles of sectioning. Hirano bodies are thought to be a phenomena of senile changes of the neuron, but their mechanism of genesis is not clear and further investigation is necessary