title: Determination of the expression time and the dose--response relationship for mutations at the HGPRT (hypoxanthine-guanine-phosphophoribosyl transferase) locus induced by X-irradiation in human diploid skin fibroblasts.
abstract: The length of the expression time for mutants resistant to 8-azaguanine or 6-thioguanine induced by X-rays was determined in human diploid skin fibroblasts. The cells were seeded in the selective medium over a period of 14 days after treatment. Direct expression of at least a part of the mutants was observed at day 0, and an increase of the mutant frequency over the entire cultivation period appeared to be due to spontaneous mutation. The dose-response relationship does not appear to deviate from linearity. The mutation rate per R had a mean value of 2.1 x 10(-7) which is about twice the value of the mutation rate found in rodent cells for the same locus.
mesh_terms: D001375:Azaguanine / Q000494:pharmacology; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D004351:Drug Resistance; D005796:Genes / Q000528:radiation effects*; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D009154:Mutation; D012867:Skin / Q000201:enzymology; D013866:Thioguanine / Q000494:pharmacology; D014965:X-Rays
chemical_list: D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine; D001375:Azaguanine