title: X-ray-induced mutation to 6-thioguanine resistance in cultured human diploid fibroblasts.
abstract: X-ray induced mutation to 6-thioguanine (6TG)-resistance was studied in early passage cultures of human diploid fibroblasts. The appearance of phenotypic induced mutants in irradiated cell populations was linearly related to the number of post-irradiation cell doublings and to the duration of the growth period prior to mutant selection; the maximum yield of X-ray induced mutants was observed when cells surviving radiation had completed 3--4 douplings (6--7 days growth) in non-selective medium. The maximum induced mutation frequency was linearly related to X-ray dose and the mutation rate was estimated to be 3.1-10(-7) mutations per viable cell per rad. The data obtained for X-ray induced mutations in cultured human diploid fibroblasts were compared with (a) similar experimental data obtained with established cell cultures and (b) with theoretical predictions of X-ray mutation rates in human germ cells.
mesh_terms: D002478:Cells, Cultured; D004171:Diploidy; D004307:Dose-Response Relationship, Radiation; D004351:Drug Resistance; D005347:Fibroblasts / Q000528:radiation effects*; D007041:Hypoxanthine Phosphoribosyltransferase / Q000378:metabolism; D009154:Mutation; D013866:Thioguanine / Q000494:pharmacology*; D014965:X-Rays
chemical_list: D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine