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Biomedical subjects

A N Davison

Publications and source records attributed to A N Davison.

At least 19 recordsLinked to original sources
PubMed1979

Accelerated ageing or selective neuronal loss as an important cause of dementia?

Extensive biochemical analysis of whole temporal lobe from cases of dementia and controls suggests that Alzheimer's disease is a primary degenerative nerve-cell disorder and not the result of accelerated ageing. There is selective loss of neocortical cholinergic neurones. Transmitter systems apart from the cholinergic system appears to be affected, but to a lesser extent, and there are no significant changes in the caudate nucleus. The change in cholinergic neurones has been confirmed in biopsy samples.

Aged↗
PubMed1979

Adrenoleukodystrophy brain cholesteryl esters and other neutral lipids.

Further examination of the neutral lipid fractions derived from brain tissue of two patients afflicted with adrenoleukodystrophy has demonstrated the presence not only of free cholesterol and cholesteryl ester, but also of appreciable free fatty acid and triglyceride. Using a gas--liquid chromatographic system normally employed for the analysis of long-chain fatty acids of galactolipids and spingomyelin, it was possible to establish the presence of long-chain (greater than C20) fatty acids in the cholesteryl ester, free fatty acid and triglyceride fractions. Long-chain fatty acids were most abundant in the cholesteryl esters. Fatty acids identified by gas--liquid chromatography and gas chromatography--mass spectroscopy included normal saturated and monounsaturated fatty acids as large as C34. Several unknown fatty acyl compounds, of as yet undetermined structure, were also observed. All investigations thus far would indicate that the pathogenesis of adrenoleukodystrophy is closely related to the aberrant metabolism of these long-chain fatty acids.

Adrenal Gland Diseases↗
PubMed1978

Alzheimer's disease: distribution of protein on sucrose density gradient centrifugation.

Material has been examined from eighteen brains, postmortem and from 3 cortical biopsies. The case were classified on clinical and morphological criteria and include cases of dementia and of nonneurological disease. Fractions were isolated from homogenates of neocortex and caudate nucleus by means of discontinuous sucorse density gradient centrifugation. The fractions were analysed for protein content. The mean protein content of fraction 1, at the interphase between 0.32 M and 0.8 M sucrose, from the cortex of the 6 Alzheimer cases was reduced. (P less than 0.005) by 25%. This deficit in protein content represents less than 5% of the total tissue protein. There were no significant differences in the protein content between other fractions from the control and Alzheimer cases.

Adult↗
PubMed1978

Proteolytic enzyme activity of blood leukocytes and cerebrospinal fluid in multiple sclerosis.

Upon stimulation by immune complexes, the polymorphonuclear (PMN) blood secretes lysosomal hydrolases, including neutral proteinase, which is concentrated in the PMN cell. Neutral and acid proteinase activity were increased and decreased, respectively, in the circulating white cells of patients with multiple sclerosis during an exacerbation of the disease, but there was no correlation with serum immune complex levels. Neutral proteolytic activity in the cellular fraction of the cerebrospinal fluid was also found to be elevated in acute multiple sclerosis, as monitored by digestion of myelin basic protein.

Antigen-Antibody Complex↗
PubMed1978

Biosynthesis of myelin and neurotoxic factors in the serum of multiple sclerosis patients.

The in vitro synthesis of myelin proteins has been studied by measuring the incorporation of [3H] lysine in developing rat brain slices. This incorporation system has been used to assay potentially gliotoxic and myelinolytic agents. A reduced incorporation of the labelled amino acid into myelin proteins occurs in the presence of anti-myelin anti-serum and anti-basic protein anti-serum. Diphtheria toxin has been found to inhibit the synthesis of myelin basic and proteolipid protein in the white matter slices of developing rats. Recent experiments with serum samples from multiple sclerosis patients in exacerbation suggest the presence of a factor which interferes with the synthesis of myelin in white matter slices.

Animals↗
PubMed1977

Uptake studies of taurine in vivo and its effects on the course of experimental focal epilepsy in rats.

The passage of orally administered taurine across the intestinal wall to the blood plasma and target sites of neuromuscular excitability has been studied. This has been correlated with the effect of repeated oral dosing on the manifestations of cobalt-induced epilepsy in the rat. The blood-brain barrier and the organ distribution of taurine uptake have important implications in testing its effect on hyperexcitability phenomena.

Animals↗
PubMed1977

delta-aminolaevulinic acid dehydratase activity and focal brain haemorrhages in lead-treated rats.

Mothers were fed a diet containing 2% lead acetate acording to the Pentschew-Garro model for inducing lead encephalopathy in young rats. At 20-22 days of age the young lead-treated rats had a mean brain Pb of 2.8 microgram/g and liver Pb of 11 microgram/g. The ALA dehydratase activity decreased 29% in brain and 69% in liver compared to controls, suggesting that the enzyme activity is related to the tissue lead level. Mothers that had received lead prior to conception gave birth to pups with a significantly raised mean blood lead level (44 microgram %). The ALA dehydratase activity in brain and liver was unchanged, suggesting that low blood lead levels may be insufficient to inhibit this enzyme in the rat. Focal haemorrhages were present, however, in the cerebral cortex of some of the pups from the lead-treated mothers. It is concluded that damage to the rat brain vascular system is a better index of lead toxicity than measurement of the lead sensitive enzyme ALA dehydratase.

Animals↗
PubMed1977

Galactolipid fatty acid composition in adrenoleukodystrophy.

The non-hydroxy and hydroxy fatty acids of the major brain galactosphingolipids, cerebroside and sulphatide, have been isolated from white matter, gray matter and myelin of 2 children with adrenoleukodystrophy and from a corresponding control. In addition, cerebroside fatty acids were recovered from a myelin-related fraction on 1 patient. In comparison to control observations, myelin and the myelin-related fraction cerebroside demonstrate a loss of C24:1 and C24h:o fatty acids from normal and hydroxy fatty acid fractions, respectively. White and gray matter galactolipids isolated from 1 patient indicated a signficant increase in short chain (C16, C18 and C18:1) non-hydroxy fatty acids. In the isolated diseased myelin, the ratio of cerebroside hydroxy to non-hydroxy fatty acids was elevated about 1.5 times above the value for normal myelin, whereas the ratio derived for the myelin-related fraction was about two-thirds the values for the control myelin cerebroside.

Adrenal Insufficiency↗