Sister-chromatid exchanges in lymphocytes of workers exposed to trichloroethylene

To detect mutagenic effects of trichloroethylene (TCE) on humans, sister-chromatid exchanges (SCEs) were analyzed in lymphocytes of 22 workers occupationally exposed to TCE and 22 matched controls. Although urinalysis in the workers revealed their obvious exposure to TCE, no increase in SCE frequencies was found in lymphocytes of the workers. SCE analysis in lymphocytes could not detect mutagenic effects by occupational exposure to TCE on humans.     

Sister-chromatid exchanges in lymphocytes from styrene-exposed boat builders

Sister-chromatid exchanges (SCE) were measured in peripheral blood lymphocytes from 40 workers in the boat-building trade. Twenty of these workers were exposed to significant amounts of styrene. The mean air concentration of styrene in the breathing zone of the boat builders was 209 mg/m3 in the 7 exposed current smokers and 230 mg/m3 in the 13 exposed non-smokers. Urinary styrene metabolites were also measured and the mean mandelic acid/creatinine ratios in the exposed, smokers was 275 mg/g, and in the exposed, non-smokers 323 mg/g. The SCE frequency in lymphocytes from the styrene-exposed group did not differ from that in the controls, although smoking significantly induced SCE in these workers.     

Sister-chromatid exchanges in lymphocytes from patients with Schistosoma hematobium

Sister-chromatid exchange (SCE) frequencies were studied in peripheral blood lymphocytes from 19 patients (13 males and 6 females) with Schistosoma hematobium, prior to the initiation of chemotherapy. The mean frequency of SCE per metaphase for the patients (both sexes) was 10.4 +/- 4.2 which was significantly higher (P less than 0.01) than the mean SCE (6.4 +/- 1.1) score for 35 healthy controls. A highly significant reduction in lymphocyte division and delay in cell-cycle progression as a result of infection were also noticed. These data indicate that infection with S. hematobium could increase SCEs in the host somatic cells.     

Sister-chromatid exchanges in lymphocytes of smokers in an experimental study

The frequency of sister-chromatid exchanges (SCEs) was studied in peripheral blood lymphocytes of 26 young male smokers and 10 non-smokers who had recently entered military service. The levels of SCEs were examined in 4 consecutive blood samples taken after short experimental periods of smoking only low-tar (LT) or medium-tar (MT) cigarettes. The incidence of SCEs was significantly higher in the the group of smokers than in the group of non-smokers. The SCE levels of the smokers were found to be associated with the personal smoking history; the observed increase in the SCE frequency correlated with the years of smoking measured as cumulative pack years. The difference in type of cigarette did not influence the SCE frequencies.     

Sister-chromatid exchanges in lymphocytes from infants with Down's syndrome

Sister-chromatid exchange (SCE) frequencies were studied in blood lymphocytes from 12 patients (3 females and 9 males) with Down's syndrome (DS). The mean frequency of SCE per metaphase for the patients (both sexes) was 9.2 +/- 0.8 which was significantly higher (P less than 0.01) than the mean SCE value (5.1 +/- 0.2) scored for 16 healthy infants (8 females and 8 males). A significant increase in the mean frequency of SCE in 12 parents of infants with DS (8.7 +/- 0.9 SCE/cell) was noticeable when compared with 20 parents of normal infants (6.3 +/- 0.1 SCE/cell). Increases in cellular division with reduction in their replication were also observed in patients with DS. Treatment with mitomycin C (0.05 micrograms/ml), hycanthone (0.1 micrograms/ml) and gamma-radiation (0.1 Gy) revealed a significant (P less than 0.01) increase in frequencies of SCE in DS lymphocytes and in those of their parents as compared to controls. These data may reveal a familial hypersensitivity reaction to these agents. The results indicate a genomic instability and deranged DNA-repair mechanisms which are accentuated by exposure to mutagenic agents, the underlying causal factor for which might be genetic.     

Bloom's syndrome. IV. Sister-chromatid exchanges in lymphocytes.

An abnormally great amount of exhange between both sister and nonsister-but-homologous chromatids is a highly characteristic feature of cultured blood lymphocytes from individuals with Bloom's syndrome. However, a population of lymphocytes which exhibit a normal amount of exchange can be detected in the blood of some individuals with this syndrome. This coexistence of cells with a greatly increased number of sister-chromatid exchanges and others with a normal number results in a phenotypic dimorphism, in apparent contradiction to the autosomal recessive mode of inheritance of the syndrome.     

Sister-chromatid exchanges in lymphocytes in women with cancer of the breast

Examination of sister-chromatid exchanges (SCE) in lymphocytes may be useful for the evaluation of exposure to mutagens/carcinogens. Information of a possible association between SCE and cancer is scarce. We therefore examined SCE in peripheral lymphocytes in 131 women, aged 17–90 years (median 51.8 years), coming to operation because of a tumor of the breast. Venous blood samples were cultivated during PHA stimulation in the presence of BrdU. After treatment with colcemid^(R), fixation, treatment with bisbenzimide and staining with Giemsa, 30 metaphases were scored in each specimen. 52 patients with peroperatively demonstrated carcinoma of the breast had 9.39 ± 0.17 SCE/cell and the remaining 79 women with non-malignant fibroadenomatosis had 9.88 ± 0.18 SCE/cell.By multiple regression analysis it appeared that the character of the tumor, the patient's age, hormone treatment and preoperative examination by mammography all were without significant influence on the SCE rate. A statistically significant correlation was found between SCE and cigarette smoking. The 45 cigarette-smoking patients had 10.49 ± 0.23 SCE/cell compared with 9.26 ± 0.13 SCE/cell in the 86 non-smokers. It was concluded that spontaneous SCE in lymphocytes is not an indicator of carcinoma of the breast.     

Sister-chromatid exchanges in human lymphocytes exposed in vitro to therapeutic ultrasound

Human lymphocytes were exposed in vitro to therapeutic levels of ultrasound (1 W/cm2, CW, 0.87 MHz, durations of 80 and 160 sec). There were no significant differences in sister-chromatid exchange frequencies between controls and ultrasound-exposed cells. Exposure of lymphocytes to the positive control (mitomycin C) resulted in a significant increase in sister-chromatid exchanges. The data do not verify a report by Stella et al. (Mutation Res., 138 (1984) 75-85) that such exposures result in increased frequencies of SCEs.     

Sister-chromatid exchanges induced in swine lymphocytes by chronic oral doses of dimethylbenzanthracene

Sister-chromatid exchanges were scored at 3-week intervals in lymphocytes of female swine ingesting daily doses of 1.25 or 2.50 mg/kg of 7,12-dimethylbenzanthracene (DMBA) for 160 days. Exchanges increased with time for about 120 days then reached a plateau at approximately 2.5 times their pretreatment level. No increase in chromosome aberrations could be identified as resulting from ingestion of the chemical. Week-old progeny of animals that had ingested the chemical throughout pregnancy showed no increase of exchanges in their peripheral lymphocytes.     

Sister-chromatid exchanges in human lymphocytes treated with 4-chloromethylbiphenyl and benzyl chloride

At non-inhibitory concentrations, 4CMB and BC both induced small, but dose-related increases in SCE. The dose-response curves gave a highly significant correlation for 4CMB (r=0.996, P<0.001) and a significant correlation for BC (r=0.757, P<0.05) which reflects the relative activities of these substances in bacterial mutation tests.     

Sister-chromatid exchanges (SCE) induced by p-dichlorobenzene in cultured human lymphocytes

We have investigated the ability of p-dichlorobenzene (p-DCB) to induce sister-chromatid exchanges (SCE) in cultured human lymphocytes. From our results we can conclude that p-DCB was able to induce a cytotoxic effect, measured as a decrease in third and second metaphases, together with an increase of SCEs.     

Sister-chromatid exchanges in lymphocytes and mutagenicity in urine of nurses handling cytostatic drugs

Sister-chromatid exchanges (SCE) in peripheral blood lymphocytes and mutagenicity of urine (Ames test) were measured in a group of 21 nurses professionally handling antineoplastic drugs and in a group of 21 unexposed controls. No differences in SCE frequencies and in urinary mutagenic activity between exposed and unexposed groups were detected. A clear positive increase in urinary mutagenicity in the TA98 Salmonella strain was observed with increasing number of cigarettes smoked, whereas no evident influence of smoking on SCE was seen. Age, coffee and alcohol consumption did not show any detectable effect in the two tests.     

Sister-chromatid exchanges in cannabis smokers.

The genotoxicity of cannabis smoking was evaluated by means of the sister-chromatid exchange (SCE) test. The SCE test is considered to be a sensitive tool for the discovery of genotoxic agents in the environment. Twenty-two tobacco smokers and 22 persons smoking both tobacco and cannabis were compared. Our findings showed that smoking in itself enhanced the SCE level significantly (18.5%) compared to a group of non-smokers, but adding smoking of cannabis to tobacco smoking did not affect the SCE level further. Based on our observations cannabis smoking could not be considered genotoxic.     

Sister-chromatid exchanges in operating room personnel.

Sister-chromatid exchange (SCE) analysis was carried out in 67 operating room personnel (anaesthetists M.D.; anaesthesia nurses and anaesthesia unit technicians) exposed to waste anaesthetic gases such as halothane, nitrous oxide and isoflurane and in 50 healthy unexposed controls. The SCE frequencies were increased significantly in operating room personnel as compared to controls. A significant increase in SCEs was found in non-smoking operating room personnel as compared to non-smoking controls. This study supports the existence of an association between occupational exposure to mutagens and an increase in SCEs in lymphocytes.