The fine structure of neurofibrillary tangles in a case of atypical presenile dementia

Creutzfeldt-Jakob disease with plaques and paired helical filaments

A 32-year-old man with rapidly progressive dementia, pyramidal signs, myoclonic jerks and dystonic movements died following brain biopsy. neuropathological examination revealed minimal neuronal loss accompanied by mild spongiform change and astrocytic reaction. Numerous plaques and neurofibrillary tangles composed of paired helical filaments dominated the ultrastructural picture. This patient had features of both Creutzfeldt-Jakob disease and Alzheimer's disease, providing additional support for the existence of an overlap between these disorders.

Electron-microscopic observation of the nucleus basilis of Meynert in human autopsy cases

The large neurons of the nucleus basalis of Meynert (nbM) were examined with the electron microscope in 13 autopsied human adults. The neurons were characterized by a prominent Nissl substance and accumulation of lipofuscin granules. Lamellar bodies were often observed among the Nissl substance. Many of the lipofuscin granules were large and had a characteristic pronounced mosaic pattern of pale areas within gray zones. Menbranous structures within the nucleus and periodic transverse processes in the cristae of the mitochondria were regarded as postmortem alterations. Alzheimer's neurofibrillary tangles (NFT) were observed in two cases. Intranuclear fibrillary bundles were identified in four cases. Crystalloid formation in rough endoplasmic reticulum was identified in two cases. Hirano body was observed in a case of parkinsonism with dementia. Axonal swelling was seen in three cases and interpreted as axonal dystrophy, an age-related phenomenon. A basal body, which is unusual in neurons of the central nervous system (CNS), was observed in one case. Lewy bodies were observed in a case of parkinsonism.

Paired helical filaments in spinal ganglion neurons of elderly rats

Ultrastructural study of spinal ganglion neurons in elderly rats (aged from 24 to 32 months) allowed the observation of spontaneously occurring paired helical filaments (PHFs). On the basis of this finding the rat may provide an animal model for the study of the morphogenesis and nature of the PHFs which are characteristic of human senile dementia of the Alzheimer type.