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Biomedical subjects

D Horvat

Publications and source records attributed to D Horvat.

At least 37 records · Page 2Linked to original sources
PubMed1991

Chromosome aberrations induced in human lymphocytes by U-235 fission neutrons: I. Irradiation of human blood samples in the "dry cell" of the TRIGA Mark II nuclear reactor.

A set-up for irradiation of biological samples in the TRIGA Mark II research reactor in Ljubljana is described. Threshold activation detectors were used for characterisation of the neutron flux, and the accompanying gamma dose was measured by TLDs. Human peripheral blood samples were irradiated "in vitro" and biological effects evaluated according to the unstable chromosomal aberrations induced. Biological effects of two types of cultivation of irradiated blood samples, the first immediately after irradiation and the second after 96 h storage, were studied. A significant difference in the incidence of chromosomal aberrations between these two types of samples was obtained, while our dose-response curve fitting coefficients alpha 1 = (7.71 +/- 0.09) x 10(-2) Gy-1 (immediate cultivation) and alpha 2 = (11.03 +/- 0.08) x 10(-2) Gy-1 (96 h delayed cultivation) are in both cases lower than could be found in the literature.

Chromosome Aberrations↗
PubMed1990

Mutagenicity of vinyl chloride in man: comparison of chromosome aberrations with micronucleus and sister-chromatid exchange frequencies.

The mutagenic effects of vinyl chloride monomer in man were studied in the lymphocyte culture with 3 methods: the chromosome aberration assay, the micronucleus assay and the sister-chromatid exchange method. Compared with control, values obtained by these tests are increased in workers occupationally exposed to vinyl chloride. In relation to non-smokers, smokers exposed to vinyl chloride show significant increases in sister-chromatid exchange frequencies. The problem of correlating the results of the chromosome aberration assay with micronucleus and sister-chromatid exchange frequencies is discussed.

Adult↗
PubMed1990

The effect of microwave radiation on the cell genome.

Cultured V79 Chinese hamster cells were exposed to continuous radiation, frequency 7.7 GHz, power density 30 mW/cm2 for 15, 30, and 60 min. The parameters investigated were the incorporation of [3H]thymidine and the frequency of chromosome aberrations. Data obtained by 2 methods (the incorporation of [3H]thymidine into DNA and autoradiography) showed that the inhibition of [3H]thymidine incorporation took place by complete prevention of DNA from entering into the S phase. The normal rate of incorporation of [3H]thymidine was recovered within 1 generation cycle of V79 cells. Mutagenic tests performed concurrently showed that even DNA macromolecules were involved in the process. In comparison with the control samples there was a higher frequency of specific chromosome lesions in cells that had been irradiated. Results discussed in this study suggest that microwave radiation causes changes in the synthesis as well as in the structure of DNA molecules.

Animals↗
PubMed1990

Localization of breaks induced by vinyl chloride in the human chromosomes of lymphocytes.

A group of 67 workers occupationally exposed to VCM was examined for the presence and distribution of breaks along the chromosomal length. Breaks induced by VCM are not randomly distributed as had been expected in a normal population. According to our results there exist highly sensitive and highly resistant locations along the chromosomes to the actions of VCM. The link between the highly sensitive segments of chromosomes, fragile sites and the activation of oncogenes is discussed.

Cells, Cultured↗
PubMed1987

A collaborative exercise on cytogenetic dosimetry for simulated whole and partial body accidental irradiation.

An experiment sponsored by the International Atomic Energy Agency was undertaken to compare dose estimation by cytogenetic analysis on aliquots of samples of irradiated blood sent by air to participating laboratories. Accidental acute whole-body irradiations to 0.7 and 2.34 Gy and half-body irradiations to 3.5 Gy were simulated with X- and gamma-rays. For the partial irradiations the size of the irradiated fraction and its dose were estimated by the Qdr and contaminated Poisson techniques. Each laboratory's in vitro dose-response data were fitted to the quadratic model by the iteratively reweighted least squares method. Interlaboratory variations in dose-response curves, and in the aberration yields and dose estimates for the simulated accidents were noted. However, in general, most participants consistently obtained results acceptably close to the true values.

Accidents↗
PubMed1981

The impact of natural radioactivity from a coal-fired power plant.

In a coal-fired power station burning coal which contained between 14--100 ppm U, 210Pb was detected in the urine of an exposed group of individuals. Chromosome aberrations (complex, numerical and the percentage of total aberrations) were also registered.

Air Pollution, Radioactive↗
PubMed1980

Genetic effect of low doses of radiation in occupationally exposed workers in coal mines and in coal fired plants.

Analyses of structural aberrations of chromosomes and of the body burden of lead-210 were carried out in a group of workers occupationally exposed to chemical pollutants and low doses of ionizing radiation during a technological process in which coal is used as fuel. A parallel study was performed in a control group of workers. In the exposed group the percentage of chromatid and chromosome aberrations and the results of radiochemical analyses were higher than in the control group.

Adult↗
PubMed1980

The mutagenicity of nitroaromatic drugs: effect of metronidazole after incubation in hypoxia in vitro.

The analysis of induction of chromosomal aberration after incubation of V79-379A cells with 10 mM metronidazole in aerobic and hypoxic conditions has shown that, in concordance with cytotoxic effect, this drug exhibits a significant clastogenic action i hypoxic, but not in oxic cells. The duration of the post-incubation period after incubation with drug is important for expression of chromosomal damage. It is probable that other nitroaromatic drugs showing enhanced cytoxicity in hypoxia, which are widely used in medicine, could also belong to such specific class mutagens.

Animals↗