Bill W J Gowans

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Poly(ADP-ribose) polymerase [PARP; NAD+ ADP-ribosyltransferase; NAD+:poly(adenosine-diphosphate-D-ribosyl)-acceptor ADP-D-ribosyltransferase, EC] is a zinc-dependent eukaryotic DNA-binding protein that specifically recognizes DNA strand breaks produced by various genotoxic agents. To study the biological function of this enzyme, we have established(More)
The effects of inhibitors of poly(ADP-ribose) synthesis on cell growth and several parameters of nucleotide metabolism have been determined. At concentrations which produced similar inhibitions of poly(ADP-ribose) synthesis, 3-acetylaminobenzamide (1 mM) had no effect on L1210 cell growth, 3-aminobenzamide (5mM) was slightly inhibitory and(More)
Methylation of deoxycytidine incorporated by DNA excision-repair was studied in human diploid fibroblasts following damage with ultraviolet radiation, N-methyl-N-nitrosourea, or N-acetoxy-2-acetylaminofluorene. In confluent, nondividing cells, methylation in repair patches induced by all three agents is slow and incomplete. Whereas after DNA replication in(More)
The purpose of this study was to determine if the cytotoxic effects of 6-aminonicotinamide are solely the result of an inhibition of poly(ADP-ribose) synthesis. The effects of 6-aminonicotinamide on cell growth, poly(ADP-ribose) synthesis and nucleotide concentrations were compared with the effect of 3-aminobenzamide, a more potent inhibitor of(More)
In confluent, stationary phase cells, an aphidicolin-sensitive DNA polymerase mediates UV-induced excision repair, but the situation in growing cells is still controversial. The sensitivity of repair synthesis to aphidicolin, an inhibitor of DNA polymerases alpha and delta, was determined in growth phase and confluent normal human fibroblasts (AG1518) using(More)
DNA repair synthesis following UV irradiation of confluent human fibroblasts has a biphasic time course with an early phase of rapid nucleotide incorporation and a late phase of much slower nucleotide incorporation. The biphasic nature of this curve suggests that two distinct DNA repair systems may be operative. Previous studies have specifically implicated(More)
Photoirradiation of aqueous solutions of DNA in the presence of Al- or Zn-tetrasulphonated phthalocyanines (AIPcS4 and ZnPcS4) causes formation of strand breaks and liberation of nucleobases. The effect of added D2O, which enhances singlet oxygen (1O2) lifetime, radical scavengers including alcohols and the spin-trap DMPO, as well as superoxide dismutase,(More)
When the NHS was created in the UK in 1948, over half of its 240 000 inpatient beds were psychiatric.1 Bed numbers increased to a peak of almost 150 000 in 1955 in England, but with the development of effective antipsychotic medications like chlorpromazine2 doctors could safely care for more patients in the community. Recent research on data from the Health(More)
The oxidation of cytosine in DNA by free radicals and other oxidants leads to an assortment of products including pyrimidine ring 5,6-saturated, 5,6-unsaturated, contraction, and fragmentation products. The formation of these products in cellular DNA may explain in part the preponderance of C to T transitions induced spontaneously and by H2O2 or ionizing(More)