Sister Chromatid Exchanges In Lymphocytes Research Articles

Increased lymphocyte sister chromatid exchange frequency in workers with exposure to low level of ethylene dichloride

The genotoxicity of low-level exposure to ethylene dichloride (EDC) and vinyl chloride monomer (VCM) in humans is not clear. We used lymphocyte sister chromatid exchange (SCE) frequency as a parameter to investigate the genotoxicity of low level EDC and VCM in VCM-manufacturing workers. The SCE frequency was determined for 51 male workers with exposure to VCM and/or EDC and for 20 male workers devoid of such exposure. Epidemiological data were obtained by questionnaire, and included history of smoking, drinking, and any medication taken, as well as a detailed occupational history. Personal- and area-sampling and analysis were conducted in order to calculate the time-weighted average (TWA) contaminant-exposure level corresponding to different job categories. Moderate EDC exposure around 1 ppm corresponded to a significantly greater SCE frequency than was the case for the low EDC exposure group ( p<0.01). However, VCM exposure of similar level was not associated with increased SCE. We conclude that EDC may cause genotoxicity at a relatively low level of exposure.

Room E, 10/17/2000 2: 00 PM - 4: 00 PM (PS) Sevoflurane Anesthesia Does Not Induce Sister Chromatid Exchanges in Lymphocytes of Children

<b>Room E, 10/17/2000 2: 00 PM - 4: 00 PM (PS) Sevoflurane Anesthesia Does Not Induce Sister Chromatid Exchanges in Lymphocytes of Children</b>

Immunotoxicity of N, N-diethylaniline in mice: effect on natural killer activity, cytotoxic T lymphocyte activity, lymphocyte proliferation response and cellular components of the spleen

We previously found that N, N-diethylaniline increased the frequency of sister chromatid exchange (SCE) of human lymphocytes to about five times that of the control value, and was as toxic as cyclophosphamide used as a positive control for SCE. To explore whether N, N-diethylaniline affects the function of lymphocytes, we evaluated its immunotoxicity using CBA/N mice. The mice were divided into four groups and received 0, 100, 200, or 400 mg/kg body weight of N, N-diethylaniline by subcutaneous injection. The following items were investigated on days 3 and 7 after injection: body weight, weight of spleen, number of splenocytes, natural killer (NK) and cytotoxic T lymphocyte (CTL) activities, and concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated lymphocyte proliferation using splenocytes. The following splenocyte phenotypes were also quantified by flow cytometry: (1) B cells; (2) total T cells; (3) CD4 + and CD8 + T cells; (4) NK; (5) macrophages and (6) nucleated erythrocytes. The splenic NK and CTL activities in exposed groups significantly decreased compared to the control in a dose-dependent manner and lymphocytes from the 200 and 400 mg/kg groups showed significantly higher spontaneous proliferation. The weight of the spleen and number of splenocytes were significantly higher in exposed groups than in the control. N, N-Diethylaniline also increased the percentages of macrophages, nucleated erythrocytes and B cells in the spleen. On the other hand, N, N-diethylaniline did not affect LPS-stimulated B cell and Con A-stimulated T cell proliferation, or the percentages of NK, total T, and CD4 + and CD8 + T cells in the spleen or the body weight of mice. The above findings indicated that N, N-diethylaniline selectively inhibited splenic NK and CTL activity and this inhibition was due to decreased NK and CTL functions, but not due to changes in the numbers of splenic NK and T cells.

Increased cytogenetic damage in outdoor painters

Painters are exposed to an extensive variety of hazardous substances such as organic solvents, lead-containing pigments and residual plastic monomers. In this particular case, workers used commercially available exterior paints and occasionally gasoline or thinner as solvents. The application or removal of paints was performed without protection (masks or gloves). To determine occupational exposure risk, a monitoring study was designed. Group selection was made after a questionnaire administration, which included questions about lifestyle and medical history to exclude exposure to other potential sources of genotoxics. Smoking and drinking habits were also considered. Blood and buccal cell samples were obtained from 25 public building male painters and from a similar number of age- and gender-matched controls. Lead levels were measured in paint samples and in individuals' blood. Organic solvents and/or its metabolites were also determined in blood. Chromosomal aberrations (CA) and sister chromatid exchanges (SCE) were determined in peripheral blood lymphocyte cultures. Also, the frequency of micronuclei (MN) in buccal cells was investigated. Painters had higher lead levels in blood ( p<0.05); CA and SCE in lymphocytes and MN in epithelial cells were also elevated ( p<0.05). Cytogenetic damage was significantly associated with occupational exposure time but not with the levels of lead found in blood.

The by-products generated during sarin synthesis in the Tokyo sarin disaster induced inhibition of natural killer and cytotoxic T lymphocyte activity

More than 5000 passengers on Tokyo subway trains were injured by the nerve gas, sarin and its by-products. Analysis of phosphor-carrying metabolites of sarin and its by-products in urine samples from the victims suggested that they were exposed not only to sarin, but also by-products generated during sarin synthesis, i.e. diisopropyl methylphosphonate (DIMP) and diethyl methylphosphonate (DEMP). We suspected genetic after-effects due to sarin by-products, thus, we checked the frequency of sister chromatid exchange (SCE) and found that SCE was significantly higher in the victims than in a control group, and that DIMP and DEMP significantly induced human lymphocyte SCE in vitro. In the present study, to explore whether DIMP and DEMP, which induced a high frequency of SCE of lymphocytes, also affected the lymphocyte functions, we examined the effect of DIMP and DEMP on splenic natural killer (NK) and splenic cytotoxic T lymphocyte (CTL) activity in mice, and NK activity of human lymphocytes in vitro. We found that DIMP and DEMP significantly inhibited NK and CTL activity in a dose-dependent manner. The inhibition induced by DIMP was stronger than that by DEMP. The effect of DIMP and DEMP on the splenic NK activity of mice was stronger than on the splenic CTL activity, and the human lymphocytes is more sensitive to DIMP and DEMP than the splenocytes of mice.

Acute toxicity and genotoxicity of aquatic hydrophobic pollutants sampled with semipermeable membrane devices

Triolein-filled semipermeable membrane devices (SPMDs) were deployed for 4 weeks in polluted water sources in Lithuania. The mixtures of pollutants sampled by the SPMDs were fractionated by size-exclusion chromatography (SEC). The fraction containing average molecular weight compounds such as polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides was screened by gas chromatography and mass spectrometry. The whole (non-fractionated) samples and their SEC fractions were tested in bioassays including Microtox™, Mutatox™, Daphnia pulex immobilization assay and the sister chromatid exchange (SCE) in human lymphocytes in vitro test. The Microtox™ test was most sensitive with the estimated EC 50 values in the range of milligrams or even micrograms per milliliter based on the amount of the SPMD triolein. Part of the observed toxicity was caused by elemental sulfur co-sampled by the SPMDs from sediments. The sum of toxicity equivalents of the SEC fractions was smaller than the relative toxicity of the whole samples indicating the presence of synergistic interactions in the complex mixtures of chemical pollutants. The toxic or genotoxic response induced by the chemical mixtures and their fractions was smaller in the D. pulex, Mutatox™ and SCE tests. In Mutatox™, a positive response was only detected without the S9 metabolic activation which indicates the presence of mainly direct-acting mutagens in the samples. Interpretation of the Mutatox™ data was difficult due to the complexity of dose–response and time–response relationships. The study has demonstrated the potential as well as some limitations of SPMDs in the monitoring of biological effects of bioavailable organic pollutants in the aquatic environment.

Cytogenetic biomonitoring in a Mexican floriculture worker group exposed to pesticides

The cytogenetic damage in floriculturists of Morelos State, Mexico, exposed to pesticides, was evaluated by mean of biological tests based on sister chromatid exchanges (SCE) in lymphocytes of peripheral blood and micronuclei (MN) in exfoliated cells of the buccal mucosa. Besides the cytogenetic analysis, the effects of pesticides exposure on the cell proliferation kinetics (CPK) by the replication index (RI) were also studied. The mitotic index (MI) to detect cytotoxic effects was also determined. Greenhouses of the towns of Santa Catarina, Jiutepec and Yecapixtla were selected for the study, because the application of chemicals to the flowers is uncontrolled. As non-exposed group, people of the town of Temisco were chosen; their activity was not related to pesticides. The SCE were analyzed in the peripheral blood of 30 persons, 22 women and 8 men, with 10 and 1.5 years of exposure to pesticides, respectively, and of 30 persons, 28 women and 2 men, that were considered as the non-exposed group. Samples of buccal mucosa were also taken from each person. Significant differences between exposed and non-exposed groups were found in SCE, CKP and MI. Besides, the MN frequencies in the exposed group were three times higher than in the non-exposed group.

Induction of sister chromatid exchanges in human peripheral blood lymphocytes by bromoform: investigation of the role of GSTT1-1 polymorphism

Brominated trihalomethanes (THMs) are disinfection by-products present frequently in chlorinated drinking water. Brominated THMs are mutagenic in a variety of systems and are carcinogenic in rodents. The metabolism of brominated THMs is thought to involve a GSH conjugation reaction leading either to formaldehyde or DNA-reactive intermediates via glutathione S-transferase-theta ( GSTT1-1), which is polymorphic in humans. In the present study, we have determined the genotoxicity of one of the brominated THMs, bromoform (BF), by measuring its ability to induce sister chromatid exchanges (SCEs) in whole-blood (WB) cultures of human peripheral blood lymphocytes from GSTT1-1+ and GSTT1-1− donors. The results showed no differences in SCEs per cell by BF between GSTT1-1+ and GSTT1-1− individuals when the cells were exposed to 5×10 −3 M BF at the beginning of cell culturing (10.8±0.85 vs. 10.57±0.47, respectively), at the 16th (9.66±0.91 vs. 9.57±0.07), or the 24th h (8.21±0.61 vs. 8.29±0.24) of cell growth. Although GSTT1-1 is expressed in the erythrocytes, the lack of expression of the GSTT1-1 gene in the target cells (lymphocytes) may account for this observation.

Genotoxicity assessment of new synthesized acridine derivative — 3,6-diamino-10-methyl-9,10-dihydroacridine

A new synthesized acridine derivative, 3,6-diamino-10-methyl-9,10-dihydroacridine (AcrH), was tested for in vitro reverse mutations with Salmonella TA strains, chromosome aberrations and sister chromatid exchanges (SCE) in human lymphocytes, and for in vivo chromosome aberrations in bone marrow of mice. Using the classic plate incorporation method, mutagenicity of AcrH in bacterial cells (TA97a, TA98, TA100 and TA102) was observed in the experiments performed with, and without, rat liver S9 metabolic activation. The reverse mutation assay showed no difference in mutagenic activity between AcrH and acriflavine (Acr +) in the test with TA97. The results of in vitro chromosome aberrations assay revealed potential clastogenicity. The test using macroculture of human lymphocytes induced mainly chromatid gaps. The experiments with human lymphocytes revealed SCE-inducing effect of AcrH and Acr +. In an in vivo study, AcrH given intraperitoneally to Balb/c mice did not cause any significant increase in the percentage of cells with aberrations compared to the negative control.

Exposure to epichlorohydrin and dimethylformamide, glutathione S-transferases and sister chromatid exchange frequencies in peripheral lymphocytes.

Workers in epoxy resin, synthetic leather, and printed circuit board manufacturing plants are exposed to epichlorohydrin (ECH), or dimethylformamide (DMF), or both. ECH, an alkylating agent, has been shown to cause malignancy in animals, but its genotoxicity in humans is unclear. DMF is a well-known hepatotoxic chemical, although evidence of its genotoxicity in humans is also limited. In this study, we examined the effects of exposure to ECH and DMF on sister chromatid exchange (SCE) in plant workers, in order to examine the genotoxicity of these two agents. Because the genotoxicity of certain agents can be modulated by metabolic traits, we also investigated influence of the glutathione S-transferase (GST) micro (GST M1) and GST theta (GST T1) genes on the genotoxicity of ECH and DMF. A total of 85 male plant workers were included in this study. The subjects were divided into five exposure groups, based on their job titles and the airborne ECH and DMF concentrations in their areas of work. A questionnaire was administered to obtain detailed occupational, smoking, alcohol consumption, and medication histories. Standardized cytogenetic methods were used to determine the frequency of sister chromatid exchange (SCE) in peripheral blood lymphocytes. GST M and GST T1 genotypes were identified using polymerase chain reaction (PCR). In analysis, smoking was significantly associated with increased SCE frequency (P<0.01). Workers with high ECH exposure also had significantly higher SCE frequencies than those with low or no ECH exposure (P<0.05). However, DMF exposure was not associated with SCE frequency. The GST M1 null genotype was also found to be associated with an increased SCE frequency (P = 0.06). We conclude that ECH exposure may be associated with genetic toxicity and that DMF does not appear to be genotoxic.

A cytogenetic study of individuals consuming drinking water with high vanadium content

Subjects which had been consuming drinking water with a high vanadium content, namely, 0.34 mg/l (0.34 ppm), for at least 10 years were investigated. Research was aimed at correlating the frequency of sister chromatid exchange (SCE) and chromosomal aberrations (CA) in human lymphocytes with vanadium values in water and urine. A questionnaire was administered to each subject to find any other vanadium‐related symptom. Data collected on both SCE and CA suggest that vanadium at concentrations affecting population under study (i.e. 0.34 mg/l) does not induce a significantly higher response.

Genetic damage in operating room personnel exposed to isoflurane and nitrous oxide.

OBJECTIVES: To evaluate genetic damage as the frequency of sister chromatid exchanges and micronuclei in lymphocytes of peripheral blood of operating room personnel exposed to waste anaesthetic gases. METHODS: Occupational...

Waste anaesthetic gases induce sister chromatid exchanges in lymphocytes of operating room personnel

Genotoxicity related to waste anaesthetic gas exposure is controversial. We have investigated the frequency of sister chromatid exchanges in peripheral lymphocytes of operating room personnel exposed to trace concentrations of isoflurane and nitrous oxide. Occupational exposure was recorded using a direct reading instrument. Frequencies of sister chromatid exchanges were measured in lymphocyte cultures of 27 non-smokers working in the operating room and 27 non-smoking controls. Personnel were exposed to an 8-h time-weighted average of nitrous oxide 11.8 ppm and isoflurane 0.5 ppm. After exposure, sister chromatid exchange frequency was increased significantly (mean 9.0 (SD 1.3) vs 8.0 (1.4) in exposed and control personnel, respectively) (P < 0.05). We conclude that exposure to even trace concentrations of waste anaesthetic gases may cause genetic damage comparable with smoking 11-20 cigarettes per day.

Sister chromatid exchange in human lymphocytes exposed to isoflurane and nitrous oxide in vitro

The question of whether or not inhalation anaesthetics are genotoxic remains controversial. Therefore, we have studied the in vitro genotoxic potential of isoflurane and nitrous oxide in human lymphocytes. Blood samples were obtained from eight healthy male, non-smoking volunteers, which were incubated and exposed to increasing concentrations of isoflurane (0.0, 0.3, 0.6 and 1.2 mmol litre-1) or 50% nitrous oxide in oxygen. Baseline sister chromatid exchange (SCE) rate per cell was mean 7.65 (SD 1.5) which increased to 9.15 (1.0), 9.55 (1.4) and 9.95 (1.8) SCE/cell during exposure to isoflurane 0.3, 0.6 and 1.2 mmol litre-1, respectively. During 50% nitrous oxide exposure, SCE rate was 9.26 (1.4). The difference between the control and exposed cells was statistically significant (P < or = 0.05). We conclude that exposure to nitrous oxide and subanaesthetic concentrations of isoflurane can produce genetic damage in peripheral lymphocytes in vitro.

Monocytes affect cell‐cycle progression but not baseline frequency of sister chromatid exchanges of pig lymphocytes

The effect of pig monocytes (MNs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression of pig lymphocytes was studied in plasma leukocyte (PLCs) and whole blood leukocyte cultures (WBCs). No variation in SCE frequency was observed between control WBC and PLC, nor did the addition of pig MNs to PLCs modify the baseline frequency of SCEs. Cell proliferation was slower in PLCs than in WBCs. Variations in cell-cycle progression of pig lymphocytes from PLC were observed both in the absence and presence of adherent cells in the culture. In MN-free cultures, lymphocytes proliferated faster than in parallel PLC cultures. However, when MNs were seeded into the cultures, cell-cycle progression gradually slowed as a function of the concentration of adherent cells present in the cultures. This finding shows that pig MNs modulate the in vitro cell-cycle progression of pig lymphocytes in a dose-dependent manner and that the low baseline SCE frequency of pig lymphocytes is independent of the presence or absence of MNs in the culture. Environ. Mol. Mutagen. 33:86–90, 1999 © 1999 Wiley-Liss, Inc.

Monocytes affect cell-cycle progression but not baseline frequency of sister chromatid exchanges of pig lymphocytes

Monocytes affect cell-cycle progression but not baseline frequency of sister chromatid exchanges of pig lymphocytes

Monocytes affect cell‐cycle progression but not baseline frequency of sister chromatid exchanges of pig lymphocytes

The effect of pig monocytes (MNs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression of pig lymphocytes was studied in plasma leukocyte (PLCs) and whole blood leukocyte cultures (WBCs). No variation in SCE frequency was observed between control WBC and PLC, nor did the addition of pig MNs to PLCs modify the baseline frequency of SCEs. Cell proliferation was slower in PLCs than in WBCs. Variations in cell-cycle progression of pig lymphocytes from PLC were observed both in the absence and presence of adherent cells in the culture. In MN-free cultures, lymphocytes proliferated foster than in parallel PLC cultures. However, when MNs were seeded into the cultures, cell-cycle progression gradually slowed as a function of the concentration of adherent cells present in the cultures. This finding shows that pig MNs modulate the in vitro cell-cycle progression of pig lymphocytes in a dose-dependent manner and that the low baseline SCE frequency of pig lymphocytes is independent of the presence or absence of MNs in the culture.

Elevated frequency of sister chromatid exchanges in lymphocytes of victims of the Tokyo sarin disaster and in experiments exposing lymphocytes to by-products of sarin synthesis

More than 5000 passengers of Tokyo subway trains were injured with toxic chemicals including the nerve gas sarin. Most of the victims examined had marked miosis and decreased serum cholinesterase activity. To monitor the genetic aftereffects of sarin exposure, we measured sister chromatid exchanges (SCEs) of the victims using peripheral blood lymphocytes. The frequency of SCEs was significantly higher in the victims than in the control group. Analyzing results using samples of urine from the victims suggested that the victims were exposed to not only sarin per se, but by-products of sarin synthesis, i.e. diisopropyl methylphosphonate (DIMP), diethyl methylphosphonate (DEMP) and ethyl isopropyl methylphosphonate (EIMP). Thus, the in vitro SCE-inducing effect of DIMP, DEMP and EIMP was examined using human lymphocytes and we obtained positive results.

Use of semipermeable membrane devices for studying effects of organic pollutants: Comparison of pesticide uptake by semipermeable membrane devices and mussels

Uptake of four pesticides—the organochlorines chlordane and endosulfan and the synthetic pyrethroids fenvalerate and allethrin—by triolein-containing semipermeable membrane devices (SPMD) and by the lake mussel Anodonta piscinalis was studied in a laboratory continuous-flow system. Uptake of the analytes by the SPMDs and mussels was linear during the exposure period of 20 d. These kinetic data were used to calculate the first-order uptake rate constants. On a SPMD-whole body basis, the uptake rates were 3.5 to 5.5 times higher in the membrane devices than in the organisms. The synthetic pyrethroids were sampled at lower rates than the organochlorines, and this difference may be attributed to the larger molecular dimensions of the pyrethroids rather than analyte molecular weight and lipophilicity, which were similar for all test compounds. Because of the disparate sampling rates, concentration factors of analytes differed between SPMDs and mussels. However, the percent composition (ratios) of analytes in SPMDs and in mussels was similar, which indicates that SPMDs may serve as good surrogates for aquatic organisms with respect to the discriminatory uptake of hydrophobic chemicals. Semipermeable membrane device dialysate, mussel extract, as well as two artificial mixtures of the four pesticides were tested with standard toxicity and genotoxicity tests, including Microtox® (inhibition of bacterial luminescence), Daphtoxkit™, and Rotoxkit™ (toxicity tests with freshwater invertebrates Daphnia pulex and Brachionus calyciflorus, respectively), and sister chromatid exchange in human lymphocytes in in vitro assay. Results of these tests suggest that integration of the SPMD technique and bioassays may be a valuable approach for the assessment of levels and effects of bioavailable hydrophobic pollutants.

Sister chromatid exchange (SCE) and micronucleus (MN) frequencies in lymphocytes of gasoline station attendants

Peripheral blood lymphocytes from 22 men with low average exposure (229 μg/m3=0.72 ppm) to benzene and 19 control men were investigated for Sister Chromatid Exchange (SCE) frequency. The majority of the men (21 exposed, 19 controls) were also investigated using the micronucleus assay (MN). The exposed subjects were employed at 10 different gas stations in or near the city (Bari/South Italy). SCE frequencies were significantly related with age and smoking habits, on the contrary no relation was observed between SCE and length of employment (SCE=7.41+0.03·age (*)+0.0001·length of employment (n.s.)+0.03·cigarette consumption (*); F=4.87; p<0.01; (*) significant; (n.s.) non-significant). MN frequencies were significantly increased in relation with length of employment; but no relation was observed when age and smoking habits were taken into consideration (regression model: MN=18.03+0.006·age (n.s.)+0.32·length of employment (*)−0.1·cigarette consumption (n.s.); F=4.138; p<0.05).