PubMed Health⌕ Search

Biomedical subjects

C Wischik

Publications and source records attributed to C Wischik.

6 recordsLinked to original sources
PubMed2000

Neuropathological findings in the very old. Results from the first 101 brains of a population-based longitudinal study of dementing disorders.

We report a unique longitudinal epidemiological study of cognitive decline in the elderly population of the city of Cambridge, UK. A population sample of people aged 75 and over was surveyed between 1984-1996 (n = 2,616) and followed 2.4, 6, and 9 years later. CAMDEX diagnostic criteria were used for clinical assessment, and the neuropathological protocol (in 101 cases) was based on the CERAD method, with additional features to allow Braak staging of neurofibrillary pathology. The main findings are of the heterogeneity of lesions to be found in very old populations, and the existence of considerable overlap in the pathologies found in the demented and nondemented. It seems that white matter (ischemic) pallor an amyloid angiopathy, as well as neuritic plaques, neurofibrillary tangles and Lewy body formation are all lesions that increase the likelihood of dementia.

Age Factors↗
PubMed1999

Association between Alzheimer's disease and the NOS3 gene.

Alzheimer's disease (AD) is the most common form of neurodegenerative disorder of later life. Genetic studies have demonstrated that the apolipoprotein E (ApoE) gene is an important susceptibility locus; however, other environmental and genetic factors operating alone or in combination with ApoE must also be involved. Among candidate genes that may contribute to this residual risk is the endothelial nitric oxide synthase (NOS3) gene. NO release from vascular endothelium accounts in large part for endothelium-derived relaxing factor bioactivity. Abnormalities of cerebral small vessels occur early in AD, and it has been demonstrated recently that beta-amyloid interacts with endothelial cells in blood vessels to produce an excess of superoxide radicals. We have genotyped 122 cases of early-onset AD (EOAD) and 317 cases of late-onset AD (LOAD) as well as 392 controls for a common structural polymorphism Glu/Asp at codon 298 in the NOS3 gene. We find a highly significant enrichment for Glu/Glu homozygotes in LOAD compared with controls. The effect appears to be independent of ApoE status. NOS3 may be a new genetic risk factor for LOAD.

Adult↗
PubMed1999

Evaluation of polymorphisms in the presenilin-1 gene and the butyrylcholinesterase gene as risk factors in sporadic Alzheimer's disease.

The E4 allele of the apolipoprotein E gene (APOE) is a major risk factor for late-onset Alzheimer's disease (LOAD) but is neither necessary nor sufficient to cause the disease. In this study, we investigated polymorphisms in the presenilin-1 (PS-1), and butyrylcholinesterase (BChE) genes, which have been implicated as risk factors for LOAD. Our data-set comprised 177 AD and 118 control patients, all of whom had been histopathologically confirmed following autopsy. We have tested homozygosity for the PS-1 allele 1 and possession of the BChE-K variant in association with APOE epsilon4 as risk factors in LOAD. Our findings support an association between the PS-1 polymorphism and LOAD, finding homozygosity for allele 1 associated with an approximately two-fold increased risk. Our data also show that in subjects greater than 75 years of age possession of both BChE-K and APOE-epsilon4 alleles is associated with an increased risk of LOAD, whilst the risk associated with APOE-epsilon4 allele alone is not significant.

Aged↗
PubMed1997

Microsatellite polymorphism of the alpha 1-antichymotrypsin gene locus associated with sporadic Alzheimer's disease.

A variant of the apolipoprotein E gene, APOE*4, is associated with both sporadic Alzheimer's disease (AD) and a subset of familial AD and this association is stronger with early as opposed to late onset AD. Both APOE*4 and alpha 1-antichymotrypsin (ACT) will accelerate the rate of amyloid filament formation and are major constituents of the plaques associated with AD. We now show that a dinucleotide microsatellite allele in the 5'-flanking sequence of the ACT gene, designated A10, in association with APOE*4 significantly increases the risk of developing sporadic AD, which accounts for the majority of AD cases.

Aged↗
PubMedDate not supplied

Immunological characterization of the region of tau protein that is bound to Alzheimer paired helical filaments.

Tau protein is known to be present in the paired helical filaments (PHFs) of Alzheimer brains. This study investigated the fragments of tau protein that remain bound to pronase-treated PHFs and conditions that lead to the release of these tau fragments from the core structure of the PHF. Antibody 423 reacted with PHFs and with fetal rat tau but not with adult rat tau, pig tau, or recombinant human tau. Three other antibodies that react with the tubulin binding region of tau only reacted with PHFs after they were disrupted with formic acid or guanidine. Other antibodies that recognize tau sequences C terminal to the tubulin binding region also recognized pronase-treated PHFs. Antibodies SMI34 and T3P that recognize phosphorylated epitopes were reactive with pronase-treated PHFs. Tau fragments from the PHF were solubilized by acid or guanidine treatment. These findings suggest that the fragments of tau that are bound to PHFs and protected from pronase digestion include sequences from the tubulin binding region to the C terminus of tau. In addition, some of these sequences appear to be conformationally or post-translationally modified.

Alzheimer Disease↗