Senile plaques (SP) and neurofibrillary tangles (NFT) are the lesions characteristic of Alzheimer's disease (AD). In this study, we examined variation in the proportion of individuals who had these lesions by race, age, and gender in a series of 138 autopsies conducted at the Office of the Chief Medical Examiner of the State of Maryland between 1990 and 1998. Cases were selected on the bases of age between 40 to 79 years and non-natural manner of death, and included 73% males, 61% subjects < 65 years of age, and 42% African Americans. Observations were conducted on histologic sections of the hippocampus, entorhinal cortex, and inferior temporal cortex stained with silver (Hirano method) and immunostained for Abeta-amyloid. We found that SP and NFT are strongly associated with age. These lesions begin to appear in the early to late 40s, depending on the anatomic location, and become common in the 6th decade, preceding by one to two decades the age at which AD becomes clinically prevalent. No difference in the prevalence of SP or NFT was found by gender or between whites and African Americans. The latter is in contrast to epidemiologic studies that suggest AD is more prevalent in African Americans than in whites.

Adult↗

PubMedDate not supplied

Biotinylated indoles as probes for indole-binding proteins.

Biotinylated indoles were prepared for application as bifunctional probes for the detection of indole-binding proteins which participate in the life processes of humans, animals, plants, and bacteria. The indole nucleus was functionalized, at ring positions 3, 5, or 6, by attachment of a 2-aminoethyl group, which was then coupled to the carboxyl moiety of biotin, via a spacer composed of 3 or 4 concatenated beta-alanine residues. The constructs thus obtained were able to inhibit tryptophanase activity, similarly to indole in a concentration-dependent manner. They also bound strongly to lysozyme and weakly to bovine and human serum albumins, in accordance with the known affinities of these proteins for indole and 3-(2-aminoethyl)indole (tryptamine). The biotin end of the protein-bound bifunctional probes could then be detected by coupling to (strept)avidin conjugated to alkaline phosphatase or horseradish peroxidase, followed by incubation with substrates which are converted by these enzymes to intensely colored or chemiluminescent products.

Alkaline Phosphatase↗

PubMedDate not supplied

Relationship between radiation injury and Alzheimer-related neurodegenerative changes.

The relationship between radiation injury and other neurodegenerative changes such as the formation of neuritic or diffuse plaques and tangles have received little attention in the literature. In the current study, archival tissue was examined from 485 patients with the diagnosis of either a primary or metastatic brain tumor, who had received radiation therapy between the initial and subsequent pathological study (either surgical or autopsy). Of those cases, 20 were identified that also contained cerebral cortex in both specimens. Sections were stained with the modified Bielschowsky technique and immunohistochemical preparations for beta-amyloid. Contrary to previous reports, the present study did not identify neurodegenerative changes typical of Alzheimer's disease as a consequence of radiation therapy.

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PubMedDate not supplied

Evidence for the production of Foà-Kurloff cells by the spleen of guinea-pigs.

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Animals↗