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Biomedical subjects

N Robinson

Publications and source records attributed to N Robinson.

At least 145 records · Page 8Linked to original sources
PubMed1980

Experience with the Bortner questionnaire as a measure of Type A behaviour in a sample of UK families.

The self-administered, 14-item Bortner questionnaire was used to characterize the Type A behaviour of the members of a group of families selected from 3 general practice registers. The questionnaire was found to be easy to complete and showed no systematic variation on repeat administration. The rank order of the 14 items was similar in the men, women and children of the study (and in a sample of Belgian men where the Bortner questionnaire had been validated against other measures of Type A behaviour). There was a social class gradient among the men but not among the women or children, and there was no correlation of this behaviour characteristic between parents and their children. This simple questionnaire may thus be an acceptable way of characterizing Type A behaviour which, it is suggested, might develop during adult life in response to occupational experiences.

Adolescent↗
PubMed1980

Lipids and lipoproteins in Friedreich's ataxia.

Friedreich's ataxia is an autosomal recessively inherited disease affecting the nervous system with a high incidence of heart involvement. Abnormalities of lipid metabolism are known to be associated with several progressive ataxic conditions. In this study of 46 Friedreich's ataxia patients, serum lipids, fatty acids and lipoproteins were assayed and compared with some earlier findings on Friedreich's ataxia and related disorders. Abnormalities of low and high density lipoproteins suggestive of a major defect have been reported; in the present study the level and chemical composition of high density lipoprotein has been assessed in 20 Friedreich's ataxia patients but previous abnormalities could not be substantiated. Lipid compositional analysis of Friedreich's ataxia central nervous tissue and heart, which has not been previously reported, did not markedly differ from control tissue.

Adult↗
PubMed1980

Effect of lecithin on disability and plasma free-choline levels in Friedreich's ataxia.

Four patients with Friedreich's ataxia took part in an open trial, in which they consumed 50-100g/day lecithin granules (containing approximately 22% phosphatidycholine) for 16 weeks, but no improvement resulted. Several unwanted effects including diarrhoea, nausea, depression, "hot flushes" and weakness were experienced. Resting levels of free-choline in plasma were within the range found in 19 normal subjects. Sixteen other patients with Friedreich's ataxia also had normal free-choline levels. Treatment with lecithin significantly increased plasma free-choline levels, but there was a trend for these to fall towards baseline levels, despite continued ingestion of lecithin.

Adolescent↗
PubMed1979

Ultrastructural demonstration of dehydrogenases in rat cerebral cortex.

Techniques for the ultrastructural demonstration of dehydrogenases in cerebral cortex are described. The best fixation for good fine structural preservation and retention of LDH and NADH-diphorase was obtained by perfusion with a misture of formaldehyde and glutaraldehyde and for SDH by perfusion with formaldehyde. Comparison of incubation conditions showed that consistent results were obtained using enzyme markers NBT and DS-NBT for LDH and NADH-diaphorase: DS-NBT was more satisfactory than NBT and BSPT for SDH. Penetration of incubation media was improved by Triton X-100: DMSO and ultrasonic treatment were less effective. The techniques enabled the first electron cytochemical demonstration of dehydrogenases in different elements of prefixed cerebral cortex. Ultrastructural sites of enzyme activities were localized within cristae and inter-membrane spaces of mitochondria in nerve cell cytoplasm and its processes, oligodendrocytes and astrocytes. Authenticity of the ultrastructural sites was confirmed by four different control experiments.

Animals↗
PubMed1979

Ultrastructural demonstration of cytochrome oxidase via cytochrome C in cerebral cortex.

A procedure for the ultrastructural cytochemical localization of cytochrome oxidase via cytochrome c in the cerebral cortex is described. Vascular perfusion fixation by formaldehyde and glutaraldehyde of different concentrations and mixtures of the two gave varying results. A mixture of 4% formaldehyde and 0.5% glutaraldehyde gave the best combination of ultrastructural preservation and retention of enzyme activity. Histochemical methods were examined for optimum incubation conditions, based on the oxidative polymerization of 3,3'-diaminobenzidine (DAB) to an osmiophilic product. The reaction product was discretely localized within intercristate and the intermembrane space of mitochondria. The staining pattern was the same in nerve cells and in neuroglia and their processed. The DAB reaction product was also found in mitochondria of the endothelial cells.

3,3'-Diaminobenzidine↗
PubMed1978

Changing social-class distribution of heart disease.

Analysis of mortality trends over 40 years in England and Wales showed that mortality from coronary heart disease had become progressively more common in working-class men and women than in those from the middle and upper classes. The change was most noticeable for men. Whereas in 1931 and 1951 heart disease was more common in men of social classes I and II, by 1961 it was more common in men of classes IV and V. This change in social-class distribution can only partly be explained by changes in diagnostic methods. The worsening mortality of classes IV and V correlated with relatively more smoking, a higher consumption of sugar, and a lower consumption of wholemeal bread in these classes. There was no correlation between change in heart disease and change in the social-class pattern of fat consumption.

Adult↗
PubMed1976

Electron cytochemical localization of gamma-aminobutyric acid catabolism in rat cerebellar cortex.

An electron cytochemical technique is described for the localization of GABA-T, the enzyme which degrades the neurotransmitter GABA, in rat cerebellar cortex. The technique allows ultrastructural demonstration of GABA-T activity by the final deposition of an electron dense formazan precipitate at reaction sites, whilst maintaining adequate ultrastructural preservation for recognition of cellular and subcellular structures. Numerous electron dense precipitates are evident as discrete punctate deposits situated mainly in mitochondria of stellate cells, basket cells and astrocytic glial cells; they are also seen in axonal or dendritic profiles at some synaptic junctions. The technique enables the first cytochemical demonstration of the mitochondrial localization of GABA-T activity in nervous tissue to be presented. It establishes that GABA-T is present in supposed GABA neurones, in pre- or post-synaptic endings, or both, of presumed inhibitory synapses and in glial cells which may be associated with these synapses. From this seemingly ubiquitous distribution, functional aspects of GABA-T in these cells is considered.

4-Aminobutyrate Transaminase↗
PubMed1976

Improved histological localization of GABA-transaminase activity in rat cerebellar cortex after aldehyde fixation.

A method for the chemical fixation of the enzyme GABA-transaminase in nervous tissue is described. It is shown that after perfusion with a formaldehyde/glutaraldehyde fixative, activity of the enzyme in cerebellar cortex is demonstrable whilst cellular morphology is preserved. Results from the improved technique have shown new sites of GABA-transaminase activity in cerebellar cortex. In view of these results a special function for glial cells in this area of brain has been suggested.

4-Aminobutyrate Transaminase↗