[Mossy fibers of the hippocampus in Alzheimer's disease].
An ultrastructural study of changes in synaptic contacts and astrocytic processes of postmortem hippocampus was performed in 5 cases of Alzheimer's disease. Mossy fibres in the stratum lucidum were examined. Pronounced alterations included clustering of synaptic vesicles, membranous damage and multilamellar profiles in synaptic terminals. There were many hypertrophic astrocytic processes around synapses. The findings suggest that the ultrastructural alterations in mossy fibers expansion, and the disturbance of glio-synaptic relationships might contribute to memory impairment in Alzheimer's disease.