Sister chromatid exchange

About: Sister chromatid exchange is a research topic. Over the lifetime, 3187 publications have been published within this topic receiving 90029 citations. The topic is also known as: replication-born DSB repair by SCE & GO:1990414.

Smoking and sister chromatid exchange

Abstract: The present survey comprises analysis of sister chromatid exchange (SCE) frequencies in the peripheral blood lymphocytes of 100 subjects: 83 healthy men and women, both cigarette smokers and nonsmokers and 17 children. Both for men (30 smoking, 22 nonsmoking) and for women (13 smoking, 18 nonsmoking) the frequency of SCEs is significantly higher among smokers (group mean 9.6±S.E. 0.2) than among nonsmokers (group mean 8.1±S.E. 0.2). No difference is detected in the frequencies of metaphase chromosome aberrations analysed in the cultured lymphocytes of the same subjects. Young children (17 subjects, mean age 1.5 years) show a significantly lower frequency of SCEs (mean 5.1±0.6) than adults. While the induction of SCEs is known to provide a sensitive indicator of mutagen/carcinogen exposure in experimental assays, it may also give important information of in vivo exposure to genotoxic agents. However, on the basis of the present data, which confirm previous results, the effects of individual smoking habits should carefully be taken into account in evaluations of the effects of exogenous agents on SCE frequencies.

Clastogenic activity from Bloom syndrome fibroblast cultures

Abstract: Media from cultures of fibroblasts of six patients with the autosomal recessive disease Bloom syndrome (BS) and from four normal fibroblast strains were analyzed for clastogenic activity towards phytohemagglutinin-stimulated human blood lymphocytes from healthy donors. Clastogenic activity was detected in concentrated ultrafiltrates of media from all six BS strains but none of the normal fibroblast strains. The frequencies of chromosomal aberrations that were induced depended on the concentration of the ultrafiltrates. Addition of bovine superoxide dismutase to the blood lymphocyte cultures strongly suppressed the clastogenic potency of the ultrafiltrates. Unconcentrated conditioned BS media were inactive. From the pore size of the ultrafilters and Sephadex G-10 chromatography it is concluded that the clastogenic material is in the molecular weight range of 1000 to 10,000. The concentrated ultrafiltrates of BS culture media also possessed the capacity to induce sister chromatid exchanges in normal human blood lymphocytes, but with relatively low efficiency. On the basis of these results and by analogy to certain collagen diseases such as systemic lupus erythematosus, we speculate that BS cells are deficient in the detoxification of active oxygen species.

Bromodeoxyuridine tablet methodology for in vivo studies of DNA synthesis.

Abstract: 5-Bromodeoxyuridine (BrdU) tablets with different physical characteristics are useful in a wide variety of studies requiring detection of DNA replication in vivo. These tablets can effect a high substitution of BrdU in DNA, thereby permitting sister chromatid differentiation in chromosomes stained with 33258 Hoechst alone or in conjunction with Giemsa. Baseline and cyclophosphamide-induced in vivo sister chromatid exchange frequencies in mouse spleen, marrow, and thymus were measured and found to be significantly greater than those in spermatogonia. Sister chromatid exchange analysis was also extended to mouse liver and to Chinese hamster and Armenian hamster marrow cells. Sister chromatid differentiation was observed in Armenian hamster meiotic tissue, and evidence for interhomolog chromatid exchange obtained.

Comparison of Mutagenicity and Induction of Sister Chromatid Exchange in Chinese Hamster Cells Exposed to Hematoporphyrin Derivative Photoradiation, Ionizing Radiation, or Ultraviolet Radiation

Abstract: Cell culture studies have been performed to compare the mutagenic potential and the induction of sister chromatid exchanges for hematoporphyrin derivative photoradiation, ionizing radiation, and UV radiation. The mutation frequency in Chinese hamster ovary cells at the hypoxanthine-guanine phosphoribosyltransferase locus was measured using resistance to 6-thioguanine. Phenotypic expression time prior to mutation selection was also examined. Treatment with either X-rays or UV was effective in producing mutants resistant to 6-thioguanine, but treatment with hematoporphyrin derivative photoradiation (at comparable toxicity levels) did not induce any mutagenic activity above background levels. The hematoporphyrin derivative incubation and photosensitization conditions used in this study did induce sister chromatid exchanges at frequencies comparable to those induced by X-rays but at lower frequencies than for UV treatments.