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Parallel results on the relationship between radiation-induced chromosomal aberrations and mutations in two eukaryotic systems
146 first-division cells is constant and Poisson distributed, and we can therefore regard the irradiated Go population as homogeneously radiosensitive. Research supported by I A E A Contract No. 1747/RB.
75 Sideris, E.G., Department of Biology Nuclear Research Centre Demokritos, Athens (Greece) Parallel results on the relationship between radiation-induced chromosomal aberrations and mutations in two eukaryotic systems The relationship between the frequency of the radiation-induced mutations and chromosomal aberrations was studied in two eukaryotic test systems, namely the plant Hordeum vulgate and the V79 cell line from the mammal Cricetulus griseus. In the former organism the frequency of radiation-induced chromosomal aberrations was estimated on the basis of radiation-induced chromosome bridges during the anaphase stages at the shoot tips of irradiated barley embryos while in the latter for the estimation of the radiation-induced chromosomal aberrations, the frequency of dicentric chromosomes in colchinized material was scored. Chlorophyll mutants and colonies resistant to 8-azaguanine were used, respectively, for the estimation of the frequency of radiation-induced mutations. The enzymatic inhibitor sodium azide was used as a post-irradiation modifier of the radiation-induced damage. In both cases the frequency of radiation-induced chromosomal aberrations was nearly doubled while the frequency of radiation-induced mutations was unaffected.
76 Simons, J.W.I.M., and P.M. Burger, Department of Radiation Genetics and Chemical Mutagenesis, University of Leiden, and Department of Dermatology, University Medical Centre, Leiden (The Netherlands) Estimation o f the m u t a n t frequency, induced in human skin, as a c o n s e q u e n c e of PUVA treatment An increasing number of patients with different skin disorders and especially with psoriasis are being treated with PUVA (8-methoxy-psoralen plus long wave ultraviolet light). It is known from the literature that this combination is mutagenic in bacteria and yeast and carcinogenic in laboratory animals. Mutation induction at the HGPRT locus was studied in V-79 Chinese hamster cells and in h u m a n diploid skin fibroblasts. It appeared that in both mutational assay systems a linear relationship exists between induced m u t a n t frequency and the product of 8-methoxy-psoralen concentration and UVA dose. The concentration range tested was 0.25--10 pg 8-MOP/ml. If a treatment with 1 J/m 2 at a concentration of 1 pg 8-MOP/ml is defined as " u n i t dose", the mutation induction per unit dose amounts of 5.5 × 10 -8 for Chinese hamster cells and to
75 Sideris, E.G., Department of Biology Nuclear Research Centre Demokritos, Athens (Greece) Parallel results on the relationship between radiation-induced chromosomal aberrations and mutations in two eukaryotic systems The relationship between the frequency of the radiation-induced mutations and chromosomal aberrations was studied in two eukaryotic test systems, namely the plant Hordeum vulgate and the V79 cell line from the mammal Cricetulus griseus. In the former organism the frequency of radiation-induced chromosomal aberrations was estimated on the basis of radiation-induced chromosome bridges during the anaphase stages at the shoot tips of irradiated barley embryos while in the latter for the estimation of the radiation-induced chromosomal aberrations, the frequency of dicentric chromosomes in colchinized material was scored. Chlorophyll mutants and colonies resistant to 8-azaguanine were used, respectively, for the estimation of the frequency of radiation-induced mutations. The enzymatic inhibitor sodium azide was used as a post-irradiation modifier of the radiation-induced damage. In both cases the frequency of radiation-induced chromosomal aberrations was nearly doubled while the frequency of radiation-induced mutations was unaffected.
76 Simons, J.W.I.M., and P.M. Burger, Department of Radiation Genetics and Chemical Mutagenesis, University of Leiden, and Department of Dermatology, University Medical Centre, Leiden (The Netherlands) Estimation o f the m u t a n t frequency, induced in human skin, as a c o n s e q u e n c e of PUVA treatment An increasing number of patients with different skin disorders and especially with psoriasis are being treated with PUVA (8-methoxy-psoralen plus long wave ultraviolet light). It is known from the literature that this combination is mutagenic in bacteria and yeast and carcinogenic in laboratory animals. Mutation induction at the HGPRT locus was studied in V-79 Chinese hamster cells and in h u m a n diploid skin fibroblasts. It appeared that in both mutational assay systems a linear relationship exists between induced m u t a n t frequency and the product of 8-methoxy-psoralen concentration and UVA dose. The concentration range tested was 0.25--10 pg 8-MOP/ml. If a treatment with 1 J/m 2 at a concentration of 1 pg 8-MOP/ml is defined as " u n i t dose", the mutation induction per unit dose amounts of 5.5 × 10 -8 for Chinese hamster cells and to