Demonstration of beta amyloid protein-containing neurofibrillary tangles in parkinsonism-dementia complex on Guam

This report concerns the immunohistochemical demonstration of beta amyloid protein-containing neurofibrillary tangles (beta-NFTs) from patients with parkinsonism-dementia complex on Guam (PDC). Formalin-fixed paraffin-embedded tissue sections from the temporal lobe of nine PDC cases and the spinal cord of three were examined. An affinity-purified antibody to the N-terminal peptide sequence of beta amyloid protein was used. beta-NFTs were demonstrated in the temporal lobes of the three oldest individuals. Some senile plaques, probably a manifestation of ageing, were also seen. The beta-NFTs were most frequent in the entorhinal cortex. Senile plaques were invariably present in the vicinity of the beta-NFTs. Conversely, in the regions without senile plaques, even though numerous neurofibrillary tangles were identifiable with the modified Bielschowsky method, no beta-NFTs were seen. The density of beta-NFTs appeared to be proportional to that of senile plaques, none was seen in cases lacking senile plaques. No beta-NFTs were detected in the spinal cords. Our data suggest that beta-NFTs result from secondary beta amyloid deposition on certain neurofibrillary tangles.