A variety of cerebral amyloid deposits in the brains of the Alzheimer-type dementia demonstrated by beta protein immunostaining.

We studied cerebral amyloid deposits in the hippocampal area immunohistochemically, using antiserum to synthetic beta peptide (1-28) in 66 patients with or without dementia and aged 17 to 91 years old. Senile plaques (SP) and amyloid angiopathy (AA) were detected in 36 (55%) and 19 (29%) patients, respectively. Also, cerebral amyloid deposits from the brains of seven patients with dementia and five patients without were studied in serial sections stained with Bodian, modified Bielschowsky, Congo red, and beta protein immunostain. In the patients with Alzheimer-type dementia (ATD) diffuse plaques, typical of this group, were stained with beta protein antiserum but not with Bodian stain, because the plaques were devoid of abnormally swollen neuritic processes. The diffuse plaques often contained one or more neuronal cell bodies. As well as primitive and classic plaques and AA, the beta protein immunostain demonstrated small deposits among the SP, small stellate deposits of layer 1, subpial fibrillar deposits, and focal cribriform deposits of parasubiculum, which may be new types of amyloid deposits. Amyloid plaques within the subcortical white matter were only found in ATD brains. In the non-demented patients various kinds of SP, including diffuse and compact ones, were immunostained. They tended to be small and few. beta protein immunostain with formic acid pretreatment is a useful method for the identification of a variety of senile cerebral amyloid deposits.