[A study of senile plaques with a combined method in brains of patients suffering from Alzheimer's disease].

Combined immunocytochemistry to phosphorylated neurofilament epitopes and periodic-acid methenamine silver (PAM) were used in the study of senile plaques (SP) in 6 patients with Alzheimer disease. SP are categorized as diffuse, primitive, mature and burned-out. Amyloid deposits are found in all of them, which is loose in diffuse and primitive plaques, and condensed in mature and burned-out types. Dystrophic neurites are only found in primitive and mature plaques. Combined methods have also shown that apparently isolated dystrophic neurites in the neuropil are always associated to amyloid deposits. These features suggest that amyloid deposition is a primary event in SP formation.