Chromosome aberrations and sister-chromatid exchange frequencies in pathology staff occupationally exposed to formaldehyde

Past studies have shown that formaldehyde is mutagenic in microbial tests and Drosophila and causes chromosomal aberrations in cultured mammalian cells. Chromosomal analysis of bone marrow cells and spermatocytes from exposed laboratory animals has failed to show any genotoxic effect. Information on individuals occupationally exposed is limited and there is no evidence to date that formaldehyde can induce chromosome damage at occupational levels of exposure. This study examines the chromosome aberration and sister-chromatid exchange frequencies in lymphocytes from a group of 6 pathology workers and 5 unexposed controls. No detectable differences could be found between the groups in either chromosomal aberration induction or sister-chromatid exchange frequencies.     

Chromosomal analysis in vinyl chloride exposed workers: Comparison of the standard technique with the sister-chromatid exchange technique

A group of 21 workers occupationally exposed to vinyl chloride and 6 controls were examined for the presence of chromosomal aberrations or sisterchromatid exchanges in their peripheral lymphocytes. These people comprised a second sampling from a group of exposed workers and controls first examined 18 months earlier. The vinyl chloride exposed workers showed levels of chromosomal aberrations elevated above those of the controls, but there was only a slight increase in sister-chromatid exchanges (per cell or per chromosome) and this increase was not statistically significant. Sister-chromatid exchanges (SCEs) were also examined from in vitro cultures of lymphocytes exposed in G₀/early G₁ and late G₁/early S phase to vinyl chloride, both with and without metabolic activation. There was no increase in SCEs in vitro without metabolic activation but there was a marked increase with metabolic activation and this increase was shown to be independent of cell-cylce phase. It thus was apparent that the small increases of SCEs in workers were not due to the inability of vinyl chloride to induce SCEs in human lymphocytes but were probably because of low exposures and SCE levels could have returned to normal relatively quickly after exposure. The present study suggested that the analysis of longer-living conventional chromosomal aberrations appeared to be a more sensitive monitor of exposure to vinyl chloride in exposed workers than the estimation of SCEs; however, it should be noted that in a 3rd sampling taken 24 months later the exposed workers had chromosomal aberration levels similar to the controls.     

Cytogenetic biomonitoring of workers from laboratories of clinical analyses occupationally exposed to chemicals

A cytogenetic monitoring study was carried out on a group of workers in clinical analysis laboratories to investigate the risk of occupational exposure to chronic low levels of chemicals.Thirty-four clinical laboratories have been involved in the study. In these laboratories, toxicants and analytical procedures utilized have been characterized. The individual occupational exposure of workers was assessed by use of a questionnaire concerning the chemical substances utilized. About 300 different chemicals have been identified.Cytogenetic analyses (chromosomal aberration and micronucleus tests) were carried out on a strictly selected group of 50 workers enrolled from these laboratories and compared to 53 controls (healthy blood donors) matched for gender and age.The exposed group shows a significantly higher frequency of genetic damage than the control group. Both chromatid and chromosome aberration frequencies in workers appear significantly higher than in controls. Similarly, comparison between micronucleated cells rates of exposed and unexposed groups show significantly higher frequencies of binucleated cells with micronucleus (BNMN) and of total micronuclei (MN tot) in workers than in controls.     

Cytogenetic biomonitoring of workers from laboratories of clinical analyses occupationally exposed to chemicals

A cytogenetic monitoring study was carried out on a group of workers in clinical analysis laboratories to investigate the risk of occupational exposure to chronic low levels of chemicals.Thirty-four clinical laboratories have been involved in the study. In these laboratories, toxicants and analytical procedures utilized have been characterized. The individual occupational exposure of workers was assessed by use of a questionnaire concerning the chemical substances utilized. About 300 different chemicals have been identified.Cytogenetic analyses (chromosomal aberration and micronucleus tests) were carried out on a strictly selected group of 50 workers enrolled from these laboratories and compared to 53 controls (healthy blood donors) matched for gender and age.The exposed group shows a significantly higher frequency of genetic damage than the control group. Both chromatid and chromosome aberration frequencies in workers appear significantly higher than in controls. Similarly, comparison between micronucleated cells rates of exposed and unexposed groups show significantly higher frequencies of binucleated cells with micronucleus (BNMN) and of total micronuclei (MN tot) in workers than in controls.     

Leather tanning workers: chromosomal aberrations in peripheral lymphocytes and micronuclei in exfoliated cells in urine

A cytogenetic study was performed on workers of a leather tanning industry. Two different approaches for the biological monitoring of the individuals were used: chromosomal aberration analysis in peripheral lymphocytes and the frequency of micronucleated cells exfoliated in urine samples. 26 men working in the sections considered to present a greater risk were included in the study. Controls were 20 men that were not exposed to chemicals. The percentage of abnormal cells was higher in workers than in controls. Smokers showed higher values of chromosome breaks than non-smokers in both groups. These differences were not statistically significant. The percentage of cells with chromatid and chromosome gaps in workers and controls was different (p less than 0.01). A slight but not significant increase in the mean percentage of micronuclei was observed in the exposed group. We conclude that exposure to chemicals during leather tanning did not produce genotoxic effects measured by chromosomal aberrations in peripheral lymphocytes and micronuclei in urine in this group of workers.     

Genotoxic evaluation of workers employed in pesticide production

Pesticides are widely used throughout the world in agriculture to protect crops and in public health to control diseases. Nevertheless exposure to pesticides can represent a potential risk to humans. Pesticide manufacturing unit workers are prone to possible occupational pesticide exposure. Therefore, this study was performed to evaluate the genotoxic effect of pesticide exposure in these workers. In the present investigation 54 pesticide workers and an equal number of control subjects were assessed for genome damage in blood lymphocytes utilizing the chromosomal aberration analysis and the buccal epithelial cell by adopting the micronucleus test. The results suggested that pesticide workers had a significantly increased frequency of chromosomal aberrations when compared with controls (mean+/-S.D., 8.43+/-2.36 versus 3.32+/-1.26; P<0.05). Similarly, the pesticides exposed workers showed a significant increase in micronucleated cells compared with controls (1.24+/-0.72 versus 0.32+/-0.26; P<0.05). Analysis of variance revealed that occupational exposure to pesticides had a significant effect on frequency of micronuclei (P<0.05), whereas smoking, age, gender and alcohol consumption had no significant effect on genetic damage (P>0.05). However, no association was found between years of exposure, smoking, age, gender, alcohol consumption and higher levels of genetic damage as assessed by the chromosomal aberration assay (P>0.05). Our findings indicate that occupational exposure to pesticides could cause genome damage in somatic cells.     

Incidence of chromosome aberrations in hothouse workers and the in vitro sensitivity of their lymphocytes to the cytogenetic action of dimatif

The cytogenetical survey of eight persons working in greenhouse and occupationally contacting with a complex of pesticides has shown a significant increase of chromosomal aberration level in comparison with the control group. It is determined that the cytogenetic effect of the greenhouse's workers differed significantly from that of the control group when lymphocytes of the examined persons were treated by the potent mutagen dimatyph in vitro. The occupational group on the whole was more sensitive than control persons to the clastogenic action of dimatyph (43.0 +/- 2.2 and 28.7 +/- 2.4%, respectively). An assumption is advanced on the modifying influence of the pesticide complex on the frequency of induced chromosomal aberrations in vitro.     

Spectrum of chromosomal aberrations in peripheral lymphocytes of hospital workers occupationally exposed to low doses of ionizing radiation

Chromosome aberrations frequency was estimated in peripheral lymphocytes from hospital workers occupationally exposed to low levels of ionizing radiation and controls. Chromosome aberrations yield was analyzed by considering the effects of dose equivalent of ionizing radiation over time, and of confounding factors, such as age, gender and smoking status. Frequencies of aberrant cells and chromosome breaks were higher in exposed workers than in controls (P = 0.007, and P = 0.001, respectively). Seven dicentric aberrations were detected in the exposed group and only three in controls, but the mean frequencies were not significantly different. The dose equivalent to whole body of ionizing radiation (Hwb) did appear to influence the spectrum of chromosomal aberrations when the exposed workers were subdivided by a cut off at 50 mSv. The frequencies of chromosome breaks in both subgroups of workers were significantly higher than in controls (< or =50 mSv, P = 0.041; >50 mSv, P = 0.018). On the other hand, the frequency of chromatid breaks observed in workers with Hwb >50 mSv was significantly higher than in controls (P = 0.015) or workers with Hwb < or =50 mSv (P = 0.046). Regarding the influence of confounding factors on genetic damage, smoking status and female gender seem to influence the increase in chromosome aberration frequencies in the study population. Overall, these results suggested that chromosome breaks might provide a good marker for assessing genetic damage in populations exposed to low levels of ionizing radiation.     

Chromosomal aberrations and sister-chromatid exchanges in lymphocytes from coke oven workers

To test whether coke oven workers, an occupational group known to be at increased cancer risk, manifest increased peripheral blood chromosomal aberration frequencies, we obtained samples from a group of 30 steelworker volunteers, who had worked several years at coke oven jobs. Exposure estimates were made using measurements of work place atmospheric coal tar pitch volatiles and work histories. No statistically significant positive regression of chromosomal aberrations on exposure estimates was found. The data from the coke oven workers were also compared with the obtained concurrently and employing precisely the same laboratory protocol from a group of male Brookhaven National Laboratory employees. The coke oven workers as a group were found to have statistically significantly elevated frequencies of chromatid aberrations and of sister-chromatid exchanges.     

Cytogenetic monitoring of petrochemical workers

The frequencies of chromosomal aberrations and sister-chromatid exchanges (SCEs) in the peripheral blood lymphocytes of 360 persons, 180 workers in a petrochemical corporation and 180 appropriate controls, were studied. A significant increase in chromosomal aberrations and SCEs, compared to the control group, was observed in two sewage-treatment workshop workers; however, there were no significant differences between petrochemical workers from four workshops and a control group.     

Results of cytogenetic testing of workers exposed to ethylene oxide

The present work was undertaken to test cytogenetically workers exposed to Ethylene oxide (EO) aiming at detecting possible adverse effects of this agent to man. In the period 1983-1984, female workers of the Laboratory of Toxicology and the Production laboratory of ethylene oxide production in a chemical plant, and female workers in a sterilization centers in a medical facilities, were repeatedly examined. In 1984, also workers in ethylene oxide production in a chemical plant were tested. For each exposed group a control group was simultaneously examined, using cytogenetic analysis of peripheral blood lymphocytes. General examination of the health condition of exposed workers were organized in the framework of preventive examinations. The exposure level to ethylene oxide in the working environment was simultaneously monitored. The results have revealed an increase in chromosomal aberrations in lymphocytes of persons exposed professionally to EO at the given exposure levels. Smoking was associated with increased frequency of chromosomal aberrations in exposed workers; the difference as compared to non-smokers was however insignificant. By contrast, difference in chromosomal aberration frequency between smokers and non-smokers was significant in the control group.     

Chromosomal aberration analysis in peripheral lymphocytes of radiation workers.

Chromosomal aberration analyses were performed in two groups of radiation workers and in a group of healthy controls. Although the level of exposure was below the accepted annual limit of 50 mSv, the yields of chromosome fragments and of total aberrations were significantly higher in the radiation workers than in the controls. However, the frequencies of dicentric and ring chromosomes in the radiation workers were not significantly different from those in the controls.     

染色体辐射效应的微机检测 Ⅱ断片率 微核率与细胞畸变率间的相关性检测

本文继前文后,按照设计的线性回归程序在“IBM—PC/XT”微型计算机上,进一步检测了断片率、微核率与细胞畸变率之间的相关性,肯定了微核测定法,断片测定法可以替代染色体畸变分析法。     

Chromosomal aberration analysis in peripheral lymphocytes of radiation workers

Chromosomal aberration analyses were performed in two groups of radiation workers and in a group of healthy controls. Although the level of exposure was below the accepted annual limit of 50 mSv, the yields of chromosome fragments and of total aberrations were significantly higher in the radiation workers than in the controls. However, the frequencies of dicentric and ring chromosomes in the radiation workers were not significantly different from those in the control     

The effect of the spontaneous level of the chromosome aberration rate on its alterations after a single local irradiation

With X-ray examinations of the stomach and duodenum, changes in chromosomal aberration frequencies in peripheral blood lymphocytes were shown to depend on the spontaneous level of these aberrations in patients exposed to a single local irradiation by 25 R. The cytogenetic efficiency of radiation exposure was found to be local in patients with the lower frequency of spontaneous chromosomal aberrations. A genetic genesis of the revealed dependence is supposed. The effect of irradiation on the correlation between radiosensitivity and radioresistance of the cytogenetic process is regarded as a possible mechanism of the appearance of the observed dependence.     

Biological monitoring of workers in the rubber industry. I. Chromosomal aberrations and sister-chromatid exchanges in lymphocytes of vulcanizers

To evaluate the possible genetic consequences of the industrial exposure among the vulcanizers of a rubber plant we measured the in vivo levels of chromosomal aberrations and sister-chromatid exchanges in peripheral lymphocytes of 34 vulcanizers and in an adequate control population. The observed chromosomal aberration frequencies were 1.9 +/- 1.4 aberrations/100 cells in the exposed group and 2.1 +/- 1.5 aberrations/100 cells in the controls. No difference was found between the two groups for the mean value of sister-chromatid exchanges (5.2 +/- 1.3 in the exposed, 5.2 +/- 0.7 in the control group). Cigarette-smoking was clearly associated with increased sister-chromatid exchange frequencies both in the exposed and in the control groups, while chromosomal aberration frequencies were not correlated with smoking habits.     

Cytogenetic studies on spray painters in south India

Studies on the frequencies of chromosomal aberrations were carried out on 104 spray painters working in automobile body reconditioning, steel furniture making and refrigerator repainting workshops in the metro city, Chennai, of south India. Randomly selected 50 male subjects not connected with this occupation were included as controls in the study. Chromosomal analysis was carried out in 48h lymphocyte (short duration) cultures representing the first mitotic division, on a subset of samples consisting of 50 spray painters, 20 controls and 72h (longer duration) cultures representing the second cell division, on all subjects. Baseline frequency of chromosomal aberrations was significantly higher among painters as compared to matched controls. Smoking and alcoholism as modulating factors had no added effect on the frequency of aberrant metaphases. Stepwise multiple linear regression analysis indicated that duration of service and age were significant factors that influence the frequency of chromosomal aberrations observed.     

Chromosomal aberrations in humans as genetic endpoints to assess the impact of pollution

The chromosomal aberration assay with peripheral blood lymphocytes has been used routinely during the last three decades to survey exposure of humans to various genotoxic agents. A large number of biomonitoring studies are based on this genetic endpoint. A great deal of data exists on occupational, life-style or medical exposure situations but less evidence of the validity of the assay is available with regards to environmental exposure. In the present paper we report our investigations on the impact of pollution in two different populations using chromosomal aberrations in human peripheral blood lymphocytes as a biomarker of chronic exposure to heavy metals and dioxins/furans for a long period and as a biomarker of acute exposure to accidentally released vinyl chloride in the air. In order to study genotoxic effects (chromosomal aberrations) of heavy metals and dioxins/furans, 52 exposed individuals from a polluted area were compared to 51 matched controls from a distant non-industrialized area. A statistically significant increase was observed in the frequency of chromosomal aberrations in peripheral blood lymphocytes from the exposed population (1.90% aberrant cells vs. 1.11% for the controls). In the case of the vinyl chloride accident, chromosomal aberrations were analyzed in peripheral blood lymphocytes from 29 potentially exposed and 29 non-exposed individuals (matched controls). The exposed group showed a statistically significant increase in the frequency of aberrant cells (1.47% vs. 1.07% for the controls).     

TNFalpha induces chromosomal abnormalities independent of ROS through IKK, JNK, p38 and caspase pathways

A role for pro-inflammatory cytokines in inflammation-related cancers has been suggested, but mechanisms are not defined. Here, we demonstrate that treatment of HeLa cells with TNFalpha increases chromosomal aberration. In contrast, IL-1beta did not increase, but rather decreased chromosomal aberration. TNFalpha and IL-1beta increased the production of H2O2 to similar levels in cells, suggesting that increased production of reactive oxygen species might not be the premier factor involved. Reducing H2O2 through overexpression of catalase or treatment of cells with NAC or BHA did not have an effect on TNF-induced chromosomal aberration. TNFalpha-induced NO production has been implicated in DNA damage. Inhibiting NO did not reduce TNF-induced chromosomal aberration. Inhibiting IKK, JNK, and p38 kinase as well as caspases decreased TNF-induced chromosomal aberration, and a correlation between TNF-induced apoptosis and CA generation was not found. Single-strand DNA breaks give rise to double-strand breaks, which then results in chromosomal breaks, when replication forks reach the single-strand breaks during S-phase. In cells progressing through S-phase, TNFalpha activation of IKK, JNK, and p38 is significantly reduced. However, these kinases were activated by IL-1beta in S-phase. The possibility that these pathways, in a TNF-specific manner, may regulate either the generation of single- and double-strand breaks or their repair, thereby resulting in increased chromosomal aberration, is discussed.     

The cytogenetic action of antilymphocyte globulin on the lymphocytes of bronchial asthma patients

Chromosomal aberration levels and frequencies of sister chromatid exchanges (SCE) in peripheral blood lymphocytes were investigated for patients with bronchial asthma treated with antilymphocyte globulin (ALG). The significant elevation of chromosomal aberration levels and SCE frequencies were revealed as compared to the healthy controls. The significant differences in chromosomal aberration levels were not observed before and after the courses of ALG therapy. At the same time the SCE frequencies appeared to be significantly decreased after the course of ALG therapy. The similar effects were observed in studies in vitro. The data obtained may suggest that ALG at the used doses does not cause any significant cytogenetic damages in the examined patients.