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Biomedical subjects

R C Jackson

Publications and source records attributed to R C Jackson.

At least 127 records · Page 7Linked to original sources
PubMed1975

Aspects of the biochemical pharmacology of cytembena.

Cytembena, at low concentrations, caused an inhibition of the in vitro growth of L1210 mouse leukaemia cells which could not be reversed by reduced folates, purines, amino acids or deoxyribonucleosides. Invitro experiments with a number of enzymes of folate metabolism produced no evidence that this drug acts as an anti-folate in mammalian tumor colls. However, Cytembena, in therapeutic doses, caused a rapid and extensive inhibition of DNA biosynthesis. There was no inhibition of RNA biosynthesis, but at high doses some inhibition of protein biosynthesis was observed. Deoxyribonucleoside triphosphates accumulated in the presence of Cytembena, suggesting that the inhibition of DNA biosynthesis was at the polymerization stage. However, in vitro experiments failed to demonstrate any direct interaction of Cytmebena with either DNA or DNA polymerase.

Acrylates↗
PubMed1969

Studies in the enzymology of glutathione metabolism in human erythrocytes.

Spectrophotometric assay methods are described for glutathione synthetase, gamma-glutamylcysteine synthetase and gamma-glutamyl transpeptidase of erythrocytes. The contents of these enzymes in normal human erythrocytes are reported. Erythrocyte glutathione synthetase is inhibited by ADP; this inhibition is competitive with respect to ATP. gamma-Glutamylcysteine synthetase is subject to feedback inhibition by GSH, and is also inhibited by NADH, and to a lesser extent by NAD(+) and NADPH. This enzyme is irreversibly inactivated by cysteamine.

Acyltransferases↗
PubMed1969

Some effects of chlorambucil on enzymes of glutathione metabolism in drug-sensitive and -resistant strains of the Yoshida ascites sarcoma.

1. Yoshida ascites cells from a strain sensitive to chemotherapy with alkylating agents contained elevated activities of the two enzymes directly responsible for glutathione synthesis, in comparison with a resistant cell strain. The activities of the glutathione-degrading enzyme gamma-glutamyltranspeptidase were comparable in both cell strains. 2. After parenteral administration of chlorambucil to rats carrying either strain of tumour, the activities of the glutathione-synthetic enzymes increased in the sensitive cells, but remained unchanged in the resistant cells. Drug treatment was without effect on the gamma-glutamyltranspeptidase activity of either cell strain. 3. The activities of a number of enzymes concerned in the oxidoreduction of glutathione remained unchanged after the administration of chlorambucil to rats carrying either strain of cells.

Acyltransferases↗