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Biomedical subjects

A N Davison

Publications and source records attributed to A N Davison.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1977

The biochemistry of brain development and mental retardation.

Mental retardation may be associated with a number of environmental factors such as undernutrition, lead poisoning or exposure to neuroactive drugs during a critical period of brain development. Possible biochemical mechanisms operating in these various conditions and in animal models are reviewed in relation to the vulnerable period hypothesis. Small brains are common in the mentally retarded, and this may be related to a developmental abnormality particularly at the level of the synapse.

Age Factors↗
PubMed1976

The selective isolation of the uterine oestradiol-receptor complex by binding to oligo(dT)-cellulose. The mediation of an essential activator in the transformation of cytosol receptor.

The [3H]oestradiol-receptor complex was selectively isolated from rat uterus cytosol by column chromatography on oligo(dT)-cellulose. Optimal conditions are described for the binding of the complex to oligo(dT)-cellulose, which is shown to be similar to its binding to DNA-cellulose. The cytosol complex has an apparent mol. wt. of 50,000-60,000 in high salt concentrations, as determined by Sephadex G-100 chromatography. This corresponds to the 4S cytoplasmic oestradiol receptor. In binding to oligo(dT)-cellulose the receptor is transformed into a form with an apparent mol.wt. of 100,000-120,000, corresponding to the 5S nuclear receptor complex. This transformation mimics the conversion in vivo of the cytoplasmic oestradiol receptor into the nuclear form. The binding of the complex to oligo(dT)-cellulose as a 5S nuclear form is unequivocally demonstrated to require the mediation of an activating present in the cytosol. The requirement for an activating factor is discussed in relation to reports that nuclear binding of the oestradiol-receptor complex is not dictated solely by the availability of the cytoplasmic oestradiol receptor.

Animals↗
PubMed1976

Preparation of 1-acyl-2-succinyl glycero-3-phosphorylcholine and evidence against its involvement in succinate dehydrogenase action.

1-Acyl-2-succinyl glycero-3-phosphorylcholine (GPC) was synthesized and its properties described. Although 1-acyl-2-succinyl GPC is a good substrate for succinate dehydrogenase, experiments on the incorporation of [2,3-14C] succinate into mitochondrial lipids gave no evidence to indicate that it is an intermediate in the enzymic oxidation of succinate to fumerate, as has been suggested earlier.

Animals↗