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Biomedical subjects

J Potter

Publications and source records attributed to J Potter.

At least 145 records · Page 8Linked to original sources
PubMed1982

William Wardill.

Explore the source record for details and available documents.

England↗
PubMed1982

Unique characteristics of rat spleen lymphocyte, L1210 lymphoma and HeLa cells in glutathione biosynthesis from sulfur-containing amino acids.

Suspensions of rat spleen lymphocyte, murine L1210 lymphoma and HeLa cells were partially depleted of glutathione (GSH) with diethyl maleate and allowed to utilize either [35S]methionine, [35S]cystine or [35S]-cysteine for GSH synthesis. Lymphocytes preferentially utilized cysteine, compared to cystine, at a ratio of about 30 to 1, which was not related to differences in the extent of amino acid uptake. Only HeLa cells displayed a slight utilization of methionine via the cystathionine pathway for cysteine and GSH biosynthesis. HeLa and L1210 cells readily utilized either cystine or cysteine for GSH synthesis. The three cell types accumulated detectable levels of intracellular cysteine glutathione mixed disulfide when incubated in a medium containing a high concentration of cystine. Various enzyme activities were measured including gamma-glutamyl transpeptidase, GSH S-transferase and gamma-cystathionase. These results support the concept of a dynamic interorgan relationship of GSH to plasma cyst(e)ine that may have importance for growth of various cell types in vivo.

Amino Acids, Sulfur↗
PubMed1980

Human FAD-dependent NAD(P)H diaphorase.

A newly discovered human diaphorase, designated diaphorase-4, which accounts for a major part of the diaphorase activity of most tissues but does not occur in erythrocytes, is described. In contrast with other human diaphorases, it is dependent on FAD for activity after electrophoresis, inhibited by low concentrations of dicoumarol and shows a marked affinity for Cibacron Blue. The molecular weight was estimated to be 49000 +/- 1800 by gel filtration. Diaphorase-4 appears to show person-to-person quantitative variation, so that about 4% of the population lack appreciable enzyme activity, but it is not yet clear whether this variation is of genetic or non-genetic origin.

Anthracenes↗
PubMed1978

Cholesterol balance during pregnancy.

The possibility was examined that the hyperlipidaemia of pregnancy may reflect abnormal cholesterol metabolism, as occurs in some other hyperlipidaemic states. Seven women were studied during the three trimesters of pregnancy and the increase in their plasma lipid concentrations was compared with their sterol balance, measured over 8-day periods in each trimester. Dietary intake of cholesterol was identical during the three study periods. Faecal bile acid excretion peaked during the second trimester and this coincided with the initial rise in plasma triglyceride levels. However, the rise in bile acid output was counter-balanced by a fall in neutral steroid excretion, so that the net cholesterol balance throughout pregnancy was not dissimilar to that reported in healthy non-pregnant women. The hyperlipidaemia of pregnancy is therefore not associated with an increase in cholesterol synthesis, although the altered ratio of bile acids to neutral steroids resembles that reported in other hypertriglycerdaemic states.

Adult↗
PubMed1977

An interpretation of human diaphorase isozymes in terms of three gene loci DIA1, DIA2 and DIA3.

NADH and NADPH diaphorase isozymes have been studied in human tissues. Evidence from rare heterozygotes suggests that the red cell and main tissue forms of NADH diaphorase are products of the same locus DIA1. NADPH-dependent diaphorase appears to be the product of a second locus DIA2. A third locus, DIA3, codes for the polymorphic sperm diaphorase. The products of this locus are also found in foetal tissues including placenta and adult brain and gonads. The products of these three loci may be distinguished by their substrate specificity, thermostability and molecular size.

Adolescent↗