Carboxy Terminal of [3-Amyloid Deposits in Aged]Human, Canine, and Polar Bear Brains

249-257, 1996.--Immunocytochemistry, using antibodies pecific for different carboxy termini of [3-amyloid, AI340 and AI342(43), was used to compare [3-amyloid deposits in aged animal models to nondemented and demented Alzheimer's disease human cases. Aged beagle dogs exhibit diffuse plaques in the absence of neurofibrillary pathology and the aged polar bear brains contain diffuse plaques and PHF-l-positiw ~ neurofibrillary tangles. The brains of nondemented human subjects displayed abundant diffuse plaques, whereas the AD cases had both diffuse and mature (cored) neuritic plaques. Diffuse plaques were positively immunostained with an antibody against A[342(43) in all examined species, whereas AI340 immunopositive mature plaques were observed only in the human brain. Anti-Al~40 strongly immunolabeled cerebrovascular [3-amyloid eposits in each of the species examined, although some deposits in the polar bear brain were preferentially abeled with anti-A[342(43). [3-Amyloid eposition was evident in the outer molecular layer of the dentate gyrus in the aged dog, polar bear, and human. Within this layer, A1342 was present as diffuse deposits, although these deposits were morphologically distinct in each of the examined animal models. In dogs, A[342 was cloud-like in nature; the polar bea