Sister Chromatid Exchange Analysis Research Articles

Cytogenetic investigations in employees from waste disposal sites

In connection with extensive health studies of employees from two big central waste disposal sites, cytogenetic investigations were performed. The subject of these special analyses was to examine whether the complex mixture of pollutants from waste disposal sites comprises a genotoxic hazardous potential. Cytogenetic analyses were performed on peripheral blood lymphocytes of 82 exposed and 71 control persons as a coded study. For chromosome analysis, 1000 cells and for sister chromatid exchange (SCE) analysis, 50 cells had been scored per person. Compared with the matched control group, a highly significant increase of the frequencies of chromosomal aberrations was detected, especially in dicentric chromosomes (4.1±0.2 vs 1.5±0.1 per 1000 cells) and acentric fragments (6.9±0.3 vs 2.8±0.2 per 1000 cells), whereas no difference was found in SCE analysis. The occurrence of multiaberrant cells with more than two dicentric chromosomes was a striking feature in waste disposal site workers (23 vs 1 in control group). Frequencies of chromosomal aberrations were similar in exposed non-smokers and smokers. Only in the control group, a significant difference was observed in the incidence of dicentric chromosomes and SCE between non-smokers and smokers. The results of the first cytogenetic investigations on employees of two waste disposal sites indicate a genotoxic hazardous potential. Further research is urgently required.

P1A33 - Sister chromatid exchange analysis in humans and animals exposed to coke oven pollutants

P1A33 - Sister chromatid exchange analysis in humans and animals exposed to coke oven pollutants

P4F125 - Analysis of chromosomal aberrations and sister chromatid exchanges in lead exposed population

P4F125 - Analysis of chromosomal aberrations and sister chromatid exchanges in lead exposed population

Induction of sister chromatid exchange by 1,2-epoxy-3-butene in cultured human lymphocytes: influence of GSTT1 genotype.

The influence of glutathione S-transferase T1 (GSTT1) genotype on the genotoxicity of 1,2-epoxy-3-butene (MEB), a metabolite of 1,3-butadiene, was assessed by the analysis of sister chromatid exchanges (SCEs) in 72-h human whole-blood lymphocyte cultures. The cultures were from 18 donors, representing both GSTT1 'positive' genotype (with at least one undeleted GSTT1 allele; GSTT1 activity present) and GSTT1 'null' genotype (homozygous deletion of the GSTT1 gene; no GSTT1 activity). As we have previously observed that allelism of glutathione S-transferase M1 (GSTM1) affects SCE induction by MEB in cultured lymphocytes, only individuals with the GSTM1 null genotype were included in this study. At 125 and 250 microM MEB (treatment at 24 h for 48 h), the mean frequencies of MEB-induced SCEs per cell (control level subtracted) were 4.5 (SD 1.8) and 8.9 (SD 1.0) for GSTT1 positive cell cultures (n = 13) and 5.3 (SD 1.2) and 12.5 (SD 1.1) for GSTT1 null cell cultures (n = 5) respectively, and the difference between the genotypes was statistically significant (P < 0.001) at the higher dose. All individual mean frequencies of SCEs induced by 250 microM MEB were higher in the GSTT1 null group (range 11.2-13.9) than in the GSTT1 positive group (range 7.2-10.8). The findings suggest that GSTT1, in addition to GSTM1, is involved in the detoxification of MEB in human whole-blood lymphocyte cultures. The deletion of the GSTT1 gene results in reduced erythrocytic detoxification capacity, thereby increasing the genotoxic effects of MEB.

High frequency of sister chromatid exchanges in lymphocytes of the patients with Behcet's disease

Behcet's disease (BD) (OMIM 109650) is an immunogenetically based multisystem disease, characterized by iridocyclitis, arthritis, orogenital ulcerations and pustular skin lesions. Viral and autoimmune etiologies have been suggested and HLA-B5 has been found to predominate in BD. The disease is most seen in Turkey and Japan. Although familial cases have been reported, the mode of inheritance is not clear. To determine the genetic instability in BD, sister chromatid exchange (SCE) analysis has been performed on peripheral lymphocytes in 23 patients and 20 healthy controls. We found significantly higher SCE rates in the patient group ( p<0.0001). Our results may indicate that genetic impairment and genetic instability may play an important part in the etiology of BD.

In vivo cytogenetic studies of the genotoxic effects of polymethyl methacrylate employed in orthopaedics.

Polymethyl methacrylate (PMMA) is a material employed as a cement in prosthesis that has been found to induce cytogenetic damage in human lymphocytes in vitro. This effect is particularly achieved before the 5th day of the exposition, while after this period no significant variations appeared. In the present study, results of cytogenetic tests in humans are reported. Sister chromatid exchange analysis and micronucleus tests have been performed on lymphocytes of patients who had undergone prosthesization with cemented prosthesis (group A) or with biological anchorage prosthesis, as control (group B). DNA damage was investigated before implantation and 5 d after surgery in both groups. Cytogenetic tests did not show any significant increase in the number of micronuclei and sister chromatid exchanges with respect to control values in patients with PMMA cemented prosthesis.

Sister chromatid exchange analysis of human cells carrying retroviral DNA

Chromosomal abnormalities have been seen in human cells following infection with human T lymphotropic virus type I (HTLV-I). Effects on sister chromatid exchange (SCE) in cells carrying HTLV-I related DNA were examined by treatment with N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). Peripheral blood specimens were obtained from 16 donors. Cells were processed for SCE analysis and sera were tested for HTLV-I antibodies by Western blot analysis. DNA from fresh lymphoid cells was analyzed by PCR-SSCP for HTLV-I genes. Of 16 donors, eight were HTLV-I seropositive and eight seronegative. Five HTLV-I infected lymphocyte cultures were also analyzed for SCE. Cells were stained immunocytochemically with anti-p19 for the viral expression. By MNNG treatment, SCE was significantly enhanced in cells derived from two seropositive donors with HTLV-I genes. In cells of six seropositive and eight seronegative donors with or without HTLV-I related DNA, SCE frequency was influenced insignificantly. Cells from all persons were negative for the p19 expression. SCE was greatly enhanced by MNNG treatment in cells from three productively infected cultures when compared with SCE in two nonproductively infected cultures.

In vivo induction of sister chromatid exchange in mouse bone marrow following oral exposure to commercial formulations of alpha-cyano pyrethroids

In vivo genetic toxicity potential of cypermethrin and deltamethrin, two alpha-cyano pyrethroid insecticides was evaluated through induction of sister chromatid exchange in mouse bone marrow cells. Groups of four healthy, adult, male albino mice were each administered with a single oral dose of 10.6, 21.1 and 32 mg cypermethrin a.i./kg b.w. or 6.6, 13.2 and 20 mg deltamethrin a.i./kg b.w. in peanut oil. For reference, a peanut-oil vehicle control and cyclophosphamide (20 mg/kg, i.p.) positive control group of animals were run in parallel. Sister chromatid exchange (SCE) analysis in bone marrow metaphase chromosomes, 24 h post-treatment, revealed modest induction with statistical significance at the highest test dose of both insecticides as compared to the vehicle control group. Further, the SCE induction by cypermethrin was more prominent than by deltamethrin. Marked induction of SCE frequency by exposure to cyclophosphamide, an alkylating mutagen, lent authenticity to these observations which, together with earlier evidence of mitotic and chromosomal abnormalities by these pyrethroids, substantiated their genetic toxicity potential and susceptibility of mammals to consequent risks.

Sister chromatid exchanges and high-frequency cells in men environmentally and occupationally exposed to ambient air pollutants: an intergroup comparison with respect to seasonal changes and smoking habit

Sister chromatid exchanges (SCE) and high-frequency cells (HFC) were measured in peripheral blood lymphocytes from men environmentally and occupationally exposed to a mixture of ambient air pollutants. The environmentally exposed individuals were inhabitants of the industrial region of Upper Silesia; those occupationally exposed were Silesian cokery or steel plant workers, while the control group consisted of rural region residents. A total of 147 males were enrolled in the study. Blood samples were collected in winter (February) and summer (September) seasons. Three major areas were investigated during the study: exposure-based dose dependency, seasonal changes, and influence of smoking habits on the SCE frequencies. The latter is frequently reported as a confounding factor in SCE analyses. In both winter and summer samples, statistically significant increases of SCE were observed in the environmentally and occupationally exposed groups compared to the controls ( p<0.001). The difference between both exposed groups was also significant ( p<0.001). An intergroup comparison was based on ANOVA after adjustment for smoking status. In all three groups of interest, a seasonal variation was found with higher levels in winter. However, in a part of the study in which each donor served as his own control, statistical differences were only found within the exposed groups. Control region inhabitants did not have significantly higher frequencies of SCE in winter, compared to summer samples. The impact of two major confounders, age of the donor and smoking habit, was investigated by multiple regression analysis. Smoking was a major factor influencing the level of SCE. Nevertheless, the effect was seen in winter samples only, which suggests an additive response and adds new information to this known effect.

Sister chromatid exchange analysis in patients exposed to low dose of iodine-131 for thyroid scintigraphy

To determine the genotoxic risk associated with diagnostic exposure to low doses of iodine 131 ( 131I), sister chromatid exchange (SCE) analysis was performed in lymphocytes of 18 non-smoking women who received 370 kBq (10 μCi) intravenous 131I sodium iodide as an adjuvant for scintigraphy for diagnosing thyroid nodularity. SCE frequencies were measured before and after 131I administration. SCE results in the pre-treated phase were regarded as control. Although SCE values 24 h after 131I administration did not show a significant increment ( p>0.05), there was a significant increase 72 h after treatment ( p<0.05). These results indicate that genetic damage might be induced by low dose of 131I.

Computerized image analysis of sister chromatid exchanges in Chinese hamster ovary cells

In this paper we show that sister chromatid exchanges (SCE) can be analysed by computer-supported determination of areas and shapes of darkly stained chromatid sections. In combination with appropriate statistical analyses, our method leads to measurements of SCE frequencies in neocarzinostatin-treated Chinese hamster ovary cells which are nearly as precise as the ones obtained by classical microscopical analyses. We discuss our data as an approach to the development of a fully automated SCE scoring system.

The primary rat hepatocyte micronucleus assay: general features

Recent advances in cell culture have allowed proliferation of primary rat hepatocytes enabling the analysis of different cytogenetic endpoints such as sister chromatid exchanges (SCE), chromosomal aberrations and micronuclei. The latter are of particular interest as preparation, staining and analysis is less time-consuming than the analysis of chromosomal aberrations and SCE what makes micronuclei an attractive short-term assay. This paper gives (1) a summary of the specific features of primary hepatocytes including ploidy, nuclearity and multipolar mitoses, (2) a summary of the culture conditions for proliferation and the proliferation kinetics, (3) an experimentally based interpretation of the comparatively high background levels of cells with micronuclei, and (4) an experiment-based discussion of approaches to circumvent the major disadvantage: the cytochalasin B method cannot be applied due to the high percentage of binucleated cells.

Lower frequency of sister chromatid exchanges and altered frequency of HLA B-region alleles among individuals with sporadic dysplastic nevi.

Sister chromatid exchanges (SCE) were analyzed in peripheral blood lymphocytes of 24 individuals, following diagnosis, and prior to surgical removal, of a sporadic dysplastic nevus (DN). Lower SCE values and variability were found in 23 sporadic DN individuals compared with controls (2.52 +/- 0.12 and 3.76 +/- 0.22 SCE/cell, respectively). These DN individuals, contrarily to healthy controls and some types of tumor patients whose cells are hypersensitive to mutagenic agents, did not show increased SCE rates as a consequence of cigarette smoking, alcohol consumption and diagnostic radiation treatments. These observations are in contrast with clinical evidence that similar lesions are both markers or risk and precursors of malignancy in individuals with multiple nevi, affected by the dysplastic nevus syndrome (DNS) or belonging to FMM (familial malignant melanoma) families. Three HLA class I alleles out of 72 tested were found more frequently in sporadic DN individuals compared with controls: B37 (p < 0.05), B52 (p < 0.01) and B70 (p < 0.01). Whether the greater chromosomal stability (as shown by the SCE analysis), and/or the altered frequency of some HLA alleles could influence the chance of developing cutaneous malignancy in DN individuals is yet to be evaluated.

SCE analysis in peripheral blood lymphocytes of a group of filling station attendants

Petroleum derivatives constitute a complex mixture of chemicals which contain known genotoxicants. Thus, chronic occupational exposure to such derivatives may be considered to possess genotoxic risk. Service station attendants are workers exposed to petroleum derivatives and, as consequence, biomonitoring studies designed to evaluate the genetic risk are required. Here we present the data on sister chromatid exchange (SCE) frequencies, proliferation rate index (PRI) and cells with high frequency of SCE (HFC) from a group of 42 attendant workers. In addition, data from a group of 45 unexposed (controls) are presented. The results obtained indicate that there are no significant differences in SCE values between the exposed workers when compared to the non-exposed individuals. The only difference is found when smoking habit is considered, the smokers having significant increases in the SCE frequency. There is a slight increase in the HFC frequency of the occupationally exposed group but the difference did not attain statistical significance.

GSTT1-dependent induction of centromere-negative and -positive micronuclei by 1,2:3,4-diepoxybutane in cultured human lymphocytes.

The role of the glutathione S-transferase T1 gene (GSTT1) in determining genotoxic response to 1,2:3,4-diepoxybutane (DEB), an epoxide metabolite of 1,3-butadiene, was studied by analysis of micronuclei (MN) in cultured human lymphocytes using the cytokinesis block method. Fluorescence in situ hybridization (FISH) with an alphoid satellite DNA probe specific for the centromeres of all human chromosomes was applied to identify MN harboring whole chromosomes. Whole-blood lymphocyte cultures of 11 GSTM1 (glutathione S-transferase M1)-positive individuals (i.e. having at least one GSTM1 allele), of whom six were GSTT1-positive (with at least one GSTT1 allele) and five GSTT1-null (GSTT1 homozygously deleted), were treated for 48 h (starting 24 h after culture initiation) with two different concentrations (2 and 5 muM) [corrected] of DEB. The GSTT1-null individuals were excessively sensitive to DEB, showing, on average, approximately 2.5 times higher induced MN frequency (control frequency subtracted) than the GSTT1-positive donors, both at 2 muM [corrected] (mean/1000 binucleate cells 29.8 versus 11.8, P < 0.05) and 5 muM [corrected] (87.6 versus 34.0, P < 0.001) DEB. In accordance with the known strong clastogenicity of DEB, MN without centromeric FISH signals were particularly increased, the difference between the two GSTT1 genotypes being statistically significant at both concentrations of DEB (mean induced MN/1000 binucleate cells 23.1 versus 9.9, P < 0.05, at 2 muM [corrected]; 69.7 versus 24.2, P < 0.001, at 5 muM) [corrected]. In addition, centromere-positive (C+) MN were induced, suggesting that DEB also has some aneuploidogenic activity. The GSTT1-null genotype showed a significantly (P < 0.05) higher mean frequency of induced C+ MN than the GSTT1-positive genotype, at both 2 (6.7 versus 1.9) and 5 muM [corrected] (17.9 versus 9.8) DEB. At the higher dose mean nuclear division index was lower in the GSTT1-null group (1.80) than in the GSTT1-positive group (2.05, P < 0.01). These findings support earlier results from the analysis of sister chromatid exchange showing that individual sensitivity to the genotoxic and cytotoxic effects of DEB is largely explained by lack of the GSTT1 gene.

Modulating factors of individual sensitivity to diepoxybutane: chromosome aberrations induced in vitro in human lymphocytes.

Peripheral blood lymphocytes from a sample of 62 randomly selected donors were analysed for spontaneous and diepoxybutane (DEB)-induced chromosomal aberrations (CA). These individuals were part of a larger sample of 122 subjects whose DEB responsiveness was evaluated by means of sister chromatid exchange (SCE) analysis. Confounding factors (such as smoking, wine and coffee consumption, occupation and haematological factors) were analysed for their effect on individual DEB-responsiveness, but no statistically significant associations were observed. Interestingly, a bimodal distribution of aberrant cell frequencies was clearly detectable, showing the existence of DEB-sensitive subjects belonging to the second mode (CA frequencies > 19%). When responsiveness evaluated by means of CA induction was compared with SCE responsiveness, it was noted that all SCE-inducible subjects (> 110.9 SCEs/cell) belonged to the second mode of CA frequency distribution. On the other hand, highly CA inducible individuals did not necessarily show a higher SCE-response, although their DEB-induced SCE frequencies were above average (92 SCEs/cell). DEB-induced CA frequency correlated with baseline levels, indicating that DEB-sensitive individuals also showed higher spontaneous chromosome damage (3.6 versus DEB-resistant 2%, P < 0.05). Finally, when simple and multiple regression analyses were carried out, DEB-sensitivity appeared negatively related to haematic concentrations of proteins and uric acid (intercept 0.131 +/- 0.011, slope -0.029 +/- 0.0116, r = -0.39; P < 0.01), probably due to its antioxidant activity. This finding confirmed previous observations on the scavenger activity of plasma factors on DEB mutagenicity.

Cytogenetic effects in mice of divinylbenzene-55 inhalation

Male B6C3F1 mice (8 weeks of age) were exposed by inhalation to divinylbenzene-55 (DVB-55), at target concentrations of 0, 25, 50 and 75 ppm for 6 h per day for 3 days. Following exposure the animals were killed, blood smears were prepared for micronucleus (MN) analysis, and the spleens were removed and cultured for sister chromatid exchange (SCE) and chromosome aberration (CA) analyses. DVB-55 induced a dose-dependent increase in SCE with the two highest doses reaching statistical significance. Similarly, there was a statistically significant although less pronounced increase in the frequency of CAs in splenocytes and MN in polychromatic erythrocytes. There was no indication of toxicity as measured by cell cycle kinetics in the splenocytes or the percentage of polychromatic erythrocytes in the peripheral blood smears. Thus, DVB-55 appears to be a weak genotoxicant in vivo.

Significance of lymphocytic sister chromatid exchange frequencies in ovarian cancer patients

Very few studies report the analysis of sister chromatid exchanges in ovarian cancer patients. We tested the null hypothesis that SCE frequency increases with the advancing stages of ovarian cancer and follows a Poisson distribution. As controls we examined age- and sex-matched healthy volunteers who had no such past history. An increased average SCE frequency was observed in ovarian cancer patients (6.34 ± 0.09) vis-à-vis controls (4.47 ± 0.12). Further, the data also suggested a stage-wise increase in the SCE frequency.

Sister chromatid exchange analysis in workers exposed to noise and vibration

Workers chronically exposed to whole-body vibration and noise are known to develop pathophysiological and psychological disturbances. The frequencies of sister chromatid exchanges (SCEs) and of cells with high frequencies of SCEs (HFCs) were analyzed in lymphocytes of 50 workers occupationally exposed to vibration and noise and of 34 controls. The exposed group included: individuals operating hand-vibrating tools (group 1), ‘test-cell operators’ (group 2) and ‘run-up’ operators (group 3) from an air base and helicopter pilots (group 4). The statistical analysis of the mean SCE count per cell was carried out by multiple regression analysis, comparing various predictor variables: exposure group, duration of exposure, age and cigarette consumption. Only cigarette consumption and exposure group were found to be significantly correlated with the mean SCE frequency. After allowing for the effects of smoking, the analysis indicates that: (1) there was no significant difference between group 1 and controls ( p > 0.05); (2) the differences between group 2 and group 0, group 3 and group 0 and group 4 and group 0 were all highly significant ( p < 0.001); (3) there was no significant difference between groups 2 and 3 ( p > 0.05), nor between groups 2 and 3 combined and group 4 ( p > 0.05); (4) exposure groups 2, 3 and 4 combined, had a significantly elevated mean SCE frequency compared to the control group ( p < 0.0001). Statistical analysis of the proportion of HFCs was consistent with these results. Our data suggest that chronic exposure to whole-body vibration and noise may lead to an increase in the level of SCEs in man. The observed effects may not reflect a direct action of these physical agents on DNA. Alternative explanations may include some of the whole-body vibration and noise-induced or stress-induced pathophysiological alterations which may indirectly induce SCE formation.

Assessment of a possible genotoxic environmental risk in sheep bred on grounds with strongly elevated contents of mercury, arsenic and antimony

A part of Northern Palatinate country (Germany) was formerly influenced by mercury mining. Today, in many cases agricultural and housing areas are placed onto or near to former dump grounds of rubble. In the soil of these areas the concentration of mercury, arsenic and antimony was found ranging from basic natural contents up to strongly elevated levels. In a biomonitoring project, sheep bred on grounds contaminated with mercury (range 1–435 mg Hg/kg dry matter), arsenic (range17–147 mg As/kg dry matter) and antimony (range 2–15 mg Sb/kg dry matter) were taken as example on the uptake of these elements from the environment and for possible effects of this exposure. Significantly elevated mercury levels were found in wool of one collective of exposed sheep (0.107 mg/kg mean vs. 0.048 mg/kg mean, p < 0.001 U-test). Surprisingly, the arsenic content of wool taken from sheep bred in the urban referential area was approx. 10 times higher than that of the sheep bred on the grounjds contaminated with arsenic (0.57 mg/kg mean vs. 0.051 mg/kg mean, p < 0.001, U-test). In general, element concentrations in the examined blood samples were low and the differences between the collectives were small: mercury was found in concentrations ranging from 0.9 μg/1 up to 2.0 μg/1 (means), arsenic and antimony were generally found in concentrations below 1 μg/1. Neither in the alkaline elution technique nor in the sister chromatid exchange (SCE) analysis significant increases in the rate of DNA-damaging effects between the different sheep collectives were detected. This indicates that the transfer rate of genotoxic compounds of mercury, arsenic or antimony from the environment is too low to register effects with AFE and SCE although the soil was highly contaminated.