ABSTRACT
The comparative study of effects of low doses of radiation on peripheral blood lymphocytes of persons occupationally exposed to radiation and non-exposed ones was carried out. The main attention was paid to radio-adaptive response forming under consistent exposure to low (0.05 Gy) and damaging (2 Gy) doses of gamma-irradiation. Noticeable heterogeneity in capacity for adaptive response forming in occupational group was revealed. The mathematical model adequate to experimental material was constructed using Kohonen neuronets.
Subject(s)
Gamma Rays , Radiation Genetics , Adult , Aged , Dose-Response Relationship, Radiation , Humans , Lymphocytes/radiation effects , Lymphocytes/ultrastructure , Mathematics , Middle Aged , Occupational ExposureABSTRACT
Mutagenic potential of the influenza virus was evaluated. Based on its capacity of inducing recessive lethal mutations in the X chromosome of Drosophila melanogaster, the influenza virus can be classified as a moderate-activity mutagen. Its mutagenicity does not depend on ability to reproduce in the cell system. This virus was shown to disrupt formation of the wing, particularly wing vein M1 + 2. Cytogenetic examination of polytene X chromosomes bearing recessive lethal mutations in Drosophila salivary glands did not reveal chromosome rearrangements. These lethals are assumed to be small deletions or point mutations. The determination of the lethal activity stage of these mutations showed that they disrupt the expression of genes functioning at various developmental stage of Drosophila. Two of them were conditionally lethal (temperature-sensitive). Two of 15 mutations analyzed were mapped to region 2B9-10-3C10-11.
Subject(s)
Drosophila melanogaster/genetics , Drosophila melanogaster/virology , Influenza A virus/genetics , Mutagenesis , X Chromosome/genetics , Animals , Female , Genes, Lethal , Genes, Recessive , Point MutationABSTRACT
Cytogenetic analysis of the population of the Beskaragai district of the Semipalatinsk oblast adjacent to the territory of the nuclear test site was conducted by means of an ecological genetic questionnaire and cytogenetic examination of metaphase chromosomes. An increase in the total mutation level in the region was observed. The frequency of chromosome aberrations among the population of the Beskaragai district (3.2%) was statistically significantly (about 1.5 times) higher than the background levels in the clear regions (from 1 to 2%). Furthermore, the frequency of aberrations in adolescents was comparable with that in the adults. The spectrum of chromosome aberrations pointed to a significant contribution of radiation component to the mutagenesis.
Subject(s)
Chromosome Aberrations , Genetics, Population , Nuclear Warfare , Radiation Effects , Adolescent , Adult , Humans , KazakhstanABSTRACT
Experiments were performed with human plasma irradiated in vitro or in vivo in order to evaluate the extent to which clastogenic factors might disturb the adaptive response to DNA-damaging factors currently studied in our laboratory. The studies were carried out with plasma isolated from whole blood given 4 Gy of X-rays in vitro and with plasma from people receiving local radiotherapy at a total dose of about 60 Gy gamma rays. Addition of irradiated plasma to culture medium did not result in a statistically significant increase in structural aberrations in chromosomes of non-irradiated normal blood.
Subject(s)
Chromosome Aberrations , Plasma/radiation effects , ABO Blood-Group System , Female , Humans , Male , Radiotherapy Dosage , Rh-Hr Blood-Group SystemSubject(s)
Cadmium/toxicity , Chlorides/toxicity , DNA/drug effects , Interferons/pharmacology , Vitamins/pharmacology , Antimutagenic Agents , Cadmium/antagonists & inhibitors , Cadmium Chloride , Chlorides/antagonists & inhibitors , DNA/radiation effects , DNA Damage , DNA Repair/drug effects , Humans , Lymphocytes/drug effects , Lymphocytes/radiation effects , Radiation-Protective Agents/pharmacologyABSTRACT
Unscheduled DNA synthesis in human fibroblasts pretreated with natural and recombinant interferons was studied by scintillated radiometry. UDS was increased in fibroblasts pretreated 7 days before UV-irradiation. Newly synthesized proteins induced in cells after interferon treatment were compared with heat shock proteins.
Subject(s)
DNA Repair/genetics , Interferons/pharmacology , Ultraviolet Rays , Cells, Cultured , DNA Repair/drug effects , Fibroblasts/drug effects , Fibroblasts/physiology , Fibroblasts/radiation effects , Heat-Shock Proteins/chemistry , Humans , Protein Biosynthesis , Proteins/chemistryABSTRACT
Proteins induced in human fibroblasts after treatment of some antimutagens (interferon, p-aminobenzoic acid, heating and vaccinia virus infection) were identified by means of polyacrylamide gel electrophoresis (10-15%) followed by fluorography of the gel. Influenza virus proteins (A/WSN/33) were used as markers to determine the molecular weights of the new proteins. The results obtained suggest that interferon, p-aminobenzoic acid, heating and vaccinia virus infection induced proteins with mol. weights of 24 and 18 kD except the protein with 76 kD observed only after heating insult.
Subject(s)
4-Aminobenzoic Acid/pharmacology , Hot Temperature , Interferons/pharmacology , Mutagenesis/drug effects , Protein Biosynthesis , Vaccinia virus/physiology , Electrophoresis, Polyacrylamide Gel , Fibroblasts/drug effects , Fibroblasts/metabolism , Fibroblasts/microbiology , Humans , Molecular Weight , Photofluorography , Proteins/drug effectsABSTRACT
The alkaline elution method was used to study DNA breaks induced by the different mutagens in human cells. Normal fibroblasts and fibroblasts from patients with homocystinuria, deficient in gamma-type repair were shown to be resistant to gamma-radiation after the vaccinia virus infection. In both cell lines there was a decrease in the number of the mutagen-induced DNA breaks.
Subject(s)
DNA Damage , DNA Repair/physiology , DNA/radiation effects , Vaccinia virus , DNA/drug effects , Fibroblasts/drug effects , Fibroblasts/microbiology , Fibroblasts/radiation effects , Homocystinuria/genetics , Homocystinuria/pathology , Humans , In Vitro Techniques , MutagensABSTRACT
Protective properties of human interferons against physical and chemical mutagens have been described earlier. This work was aimed at detecting an optimum of protective action of interferons in human fibroblasts using two criteria: the number of single-strand DNA breaks formed and the index of DNA repair synthesis. The protective ability of interferon was shown to be expressed starting after 4 h of cells' pretreatment and proceeding through 40 h in experiments with N-methyl-N-nitro-N-nitrosoquanidin. The phenomenon of stimulation of DNA repair synthesis in human cells pretreated with interferon proceeded even after replating cells during 8 h in the experiments with UV irradiation.
Subject(s)
DNA Damage , DNA Repair/drug effects , Interferon Type I/pharmacology , Mutagens , Cells, Cultured , DNA, Single-Stranded/drug effects , DNA, Single-Stranded/radiation effects , Fibroblasts , Humans , Ultraviolet RaysABSTRACT
The effect of N-nitroso-N-methylurea (NMU), N-nitroso-N,N'-dimethylurea (NDMU) and N-nitroso-N-ethylurea (NEU) at doses less than 100 mkg/ml on mutability of Salmonella typhimurium strains of Ames' system (G-46, TA-1950, TA-1535, TA-100, TA-1538) has been studied. NMU and NEU at doses of 5-10 mkg/ml have been found to increase the survival and decrease the number of reversions from auxotrophity in histidine to prototrophity. The effect of given doses of NMU and NEU on bacteria repair activity has been shown. The role of pk M101 plasmide in this process is being discussed. NDMU in contrast to NMU and NEU induces read frome shift mutations and exhibits high mutagenous activity at all doses examined.
Subject(s)
Mutation , Nitrosourea Compounds/pharmacology , Salmonella typhimurium/drug effects , Dose-Response Relationship, Drug , Mutagenicity Tests , Salmonella typhimurium/genetics , Time FactorsABSTRACT
Streptomyces griseus 15 was subjected to the action of 1,4-bis-diazoacetyl butane (DAB) taken at concentrations of 10 to 50,000 micrograms/ml. Small doses (10-100 micrograms/ml) of DAB had no mutagenic action and activated the cultural growth (the viability and the survival rate of spores increased on solid media, while the biomass yield rised in liquid media). Experiments were conducted using the method of orthogonal planning of a bifactorial experiment, and the role of the exposure time rised with a decrease in the mutagen concentration.
Subject(s)
Diazonium Compounds/pharmacology , Growth Substances/pharmacology , Mutagens/pharmacology , Streptomyces griseus/drug effects , Culture Media/pharmacology , Dose-Response Relationship, Drug , Spores, Bacterial/drug effectsABSTRACT
The results of studies of physico-chemical and biological properties of virus-specific ribonucleoproteins (RNP) in influenza infection are presented. Particular attention is given to the infectious properties of RNP. The earliest infectivity was found to be associated with RNP structures sedimenting from nuclear extract in a zone of 30-40S.