Evaluation of sister chromatid exchange and chromosomal aberration frequencies in peripheral blood lymphocytes of gasoline station attendants

Assessment of genotoxicity biomarkers in gasoline station attendants due to occupational exposure

Gasoline station attendants are exposed to numerous chemicals that might have genotoxic and carcinogenic potential, such as benzene in fuel vapor and particulate matter and polycyclic aromatic hydrocarbons in vehicle exhaust emission. According to IARC, benzene and diesel particulates are Group 1 human carcinogens, and gasoline has been classified as Group 2A "possibly carcinogenic to humans." At gas stations, self-service is not implemented in Turkey; fuel-filling service is provided entirely by employees, and therefore they are exposed to those chemicals in the workplace during all working hours. Genetic monitoring of workers with occupational exposure to possible genotoxic agents allows early detection of cancer. We aimed to investigate the genotoxic damage due to exposures in gasoline station attendants in Turkey. Genotoxicity was evaluated by the Comet, chromosomal aberration, and cytokinesis-block micronucleus assays in peripheral blood lymphocytes. Gasoline station attendants (n = 53) had higher tail length, tail intensity, and tail moment values than controls (n = 61). In gasoline station attendants (n = 46), the frequencies of chromatid gaps, chromosome gaps, and total aberrations were higher compared with controls (n = 59). Increased frequencies of micronuclei and nucleoplasmic bridges were determined in gasoline station attendants (n = 47) compared with controls (n = 40). Factors such as age, duration of working, and smoking did not have any significant impact on genotoxic endpoints. Only exposure increased genotoxic damage in gasoline station attendants independently from demographic and clinical characteristics. Occupational exposure-related genotoxicity risk may increase in gasoline station attendants who are chronically exposed to gasoline and various chemicals in vehicle exhaust emissions.

Sulfoxaflor insecticide exhibits cytotoxic or genotoxic and apoptotic potential via oxidative stress-associated DNA damage in human blood lymphocytes cell cultures

The need for foodstuff that emerged with the rapidly increasing world population made fertilizers and pesticides inevitable to obtain maximum efficiency from existing agricultural areas. Sulfoxaflor is currently the only member of the new sulfoximine insecticide subclass of nicotinic acetylcholine receptor agonists. In the study, it was aimed to determine the in vitro genetic, oxidative damage potential, genotoxic and apoptotic effects of three different concentrations (10 µg/mL, 20 µg/mL and 40 µg/mL) of sulfoxaflor insecticide in the cultures of blood lymphocytes. In this study, the single-cell gel electrophoresis (comet), Cytokinesis Block Micronuclues Test (MN test), flow cytometry and measurement of Catalase (CAT) enzyme activity were used to determine genotoxic, apoptotic effects and oxidative damage potential, respectively. It found that there is a decrease in CPBI values and Live cell numbers. It was observed an increase in late apoptotic and necrotic cell numbers, Micronucleus frequency, and Comet analysis parameters (GDI and DCP). There is a significant difference between negative control and all concentration of insecticide for Cytokinesis Block Proliferation Index (CBPI) values and late apoptotic, necrotic and viable cell counts. An increase in CAT enzyme levels was observed at 10 and 20 µg/mL concentrations compared to control., It is found that CAT enzyme activity was inhibited at concentrations of 40 µg/mL. This study is crucial as it is the first study to investigate the impact of Sulfoxaflor insecticide on peripheral blood lymphocyte cells. The genotoxic, oxidative damage, and apoptotic effects of Sulfoxafluor insecticide on the results obtained and its adverse effects on other organisms raise concerns about health and safety.

Derivation of an occupational exposure limit for benzene using epidemiological study quality assessment tools

This paper derives an occupational exposure limit for benzene using quality assessed data. Seventy-seven genotoxicity and 36 haematotoxicity studies in workers were scored for study quality with an adapted tool based on that of Vlaanderen et al., 2008 (Environ Health. Perspect. 116 1700-5). These endpoints were selected as they are the most sensitive and relevant to the proposed mode of action (MOA) and protecting against these will protect against benzene carcinogenicity. Lowest and No- Adverse Effect Concentrations (LOAECs and NOAECs) were derived from the highest quality studies (i.e. those ranked in the top tertile or top half) and further assessed as being "more certain" or "less certain". Several sensitivity analyses were conducted to assess whether alternative "high quality" constructs affected conclusions. The lowest haematotoxicity LOAECs showed effects near 2 ppm (8 h TWA), and no effects at 0.59 ppm. For genotoxicity, studies also showed effects near 2 ppm and showed no effects at about 0.69 ppm. Several sensitivity analyses supported these observations. These data define a benzene LOAEC of 2 ppm (8 h TWA) and a NOAEC of 0.5 ppm (8 h TWA). Allowing for possible subclinical effects in bone marrow not apparent in studies of peripheral blood endpoints, an OEL of 0.25 ppm (8 h TWA) is proposed.

Occupational benzene exposure and the risk of genetic damage: a systematic review and meta-analysis

Background

Benzene, an important component of organic solvents, is commonly used in industry. Meanwhile, benzene is a human carcinogen leading to leukemia. Although the links between benzene and various types of genetic damage indicators have been evaluated in several studies, but their results remain inconsistent. So we conducted a meta-analysis, and to explore the influence of low concentration benzene exposure on workers’ genetic damage indicators using 3.25 mg/m³ as the boundary value, in order to provide a basis for improved prevention and control of the harm from benzene exposure to the occupational population.

Methods

We conducted a search of five databases, including Pub Med, Web of Science, China National Knowledge Infrastructure (CNKI), Wan Fang Data and Chongqing VIP, to identify relevant articles up to December 25, 2018. Two researchers independently extracted and evaluated the data according to the inclusion and exclusion criteria of the literature. The imported articles were managed by Endnote X7, and the data were extracted and sorted by Excel 2013. We utilized Stata 12.0 software to perform the meta-analysis in the present study.

Results

A total of 68 eligible articles were finally included for the synthetic analyses. The meta-analysis results showed that occupational benzene exposure led to significantly increased Micronucleus (MN) frequency, Sister chromatid exchange (SCE) frequency, Chromosome aberration (CA) frequency, Olive Tail moment (OTM), Tail moment (TM), Tail length (TL), and Tail DNA% (T DNA%) compared to the control group (P < 0.05), and the pooled effect value estimates were 1.36, 0.98, 0.76, 1.06, 0.96, 1.78, and 1.42, respectively. Subsequent analysis of the effect of low concentration benzene exposure on genetic damage found significantly increased MN frequency increased compared with the control group (P < 0.05).

Conclusions

Occupational benzene exposure can affect multiple genetic damage indicators. Even at an exposure concentration lower than 3.25 mg/m³, benzene exposure has genotoxicity. These data provide an important scientific basis for the further revision of occupational disease prevention strategies. At the same time, increased attention should be focused on the health monitoring of the occupational population exposed to benzene, and health management should be strengthened to improve the health of the occupational population.

Spatiotemporal variations and characterization of the chronic cancer risk associated with benzene exposure

A spatiotemporal analysis of benzene was performed in east of the USA and in a representative station in Baltimore County, in order to assess its trend over a 25-year time span between 1993 and 2018. A novel time series analysis technique known as TBATS (an ensemble of Trigonometric seasonal models, Box-Cox transformation, ARMA error plus Trend and Seasonal components) was applied for the first time on an air contaminant. The results demonstrated an annual seasonality and a continuously declining trend in this respect. The success of Reformulated Gasoline Program (RFG), initiated in 1995, was obviously detected in time series data since the daily benzene concentrations reduced to one-sixth of its original level in 1995. In this regard, the respective values of mean absolute scaled error (MASE) were 0.35 and 0.45 for training and test series. Given the observed concentrations of benzene, the hot spot areas in east of the US were identified by spatial analysis, as well. A chronic cancer risk was followed along the study area, by both a deterministic and probabilistic risk assessment (PRA) techniques. It was indicated that children are at higher risk than that of adults. The range of estimated risk values for PRA was higher and varied between 6.45 × 10^-6 and 1.68 × 10^-4 for adults and between 8.13 × 10^-6 and 8.29 × 10^-4 for children. According to the findings of PRA, and referring to the threshold level of 1 × 10^-4, only 1.2% of the adults and 28.77% of the children were categorized in an immediate risk group.

Environmental Assessment and Evaluation of Oxidative Stress and Genotoxicity Biomarkers Related to Chronic Occupational Exposure to Benzene

Environmental and occupational exposure to benzene from fuels is a major cause for concern for national and international authorities, as benzene is a known carcinogen in humans and there is no safe limit for exposure to carcinogens. The objective of this study was to evaluate the genotoxic effects of chronic occupational exposure to benzene among two groups of workers: filling station workers (Group I) and security guards working at vehicles entrances (Group II), both on the same busy highway in Rio de Janeiro, Brazil. Sociodemographic data on the workers were evaluated; the concentration of benzene/toluene (B/T) in atmospheric air and individual trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (S-PMA) were measured; oxidative stress was analyzed by catalase (CAT), glutathione S-transferase (GST), superoxide dismutase (SOD), thiol groups (THIOL) and malondialdehyde (MDA); genotoxicity was measured by metaphases with chromosomal abnormalities (MCA) and nuclear abnormalities, comet assay using the enzyme formamidopyrimidine DNA glycosylase (C-FPG), and methylation of repetitive element LINE-1, CDKN2B and KLF6 genes. Eighty-six workers participated: 51 from Group I and 35 from Group II. The B/T ratio was similar for both groups, but Group I had greater oscillation of benzene concentrations because of their work activities. No differences in ttMA and S-PMA, and no clinical changes were found between both groups, but linearity was observed between leukocyte count and ttMA; and 15% of workers had leukocyte counts less than 4.5 × 10⁹ cells L^-1, demanding close worker's attention. No differences were observed between the two groups for THIOL, MDA, MCA, or nuclear abnormalities. A multiple linear relationship was obtained for the biomarkers MCA and C-FPG. A significant correlation was found between length of time in current job and the biomarkers C-FPG, MCA, GST, and MDA. Although both populations had chronic exposure to benzene, the filling station workers were exposed to higher concentrations of benzene during their work activities, indicating an increased risk of DNA damage.

Enhanced H3K4me3 modifications are involved in the transactivation of DNA damage responsive genes in workers exposed to low-level benzene

In this study, we explore whether altered global histone modifications respond to low-level benzene exposure as well as their association with the hematotoxicity. We recruited 147 low-level benzene-exposed workers and 122 control workers from a petrochemical factory in Maoming City, Guangdong Province, China. The internal exposure marker level, urinary S-phenylmercapturic acid (SPMA), in benzene-exposed workers was 1.81-fold higher than that of the controls (P < 0.001). ELISA method was established to examine the specific histone modifications in human peripheral blood lymphocytes (PBLCs) of workers. A decrease in the counts of white blood cells (WBC), neutrophils, lymphocytes, and monocytes appeared in the benzene-exposed group (all P < 0.05) compared to the control group. Global trimethylated histone 3 lysine 4 (H3K4me3) modification was enhanced in the benzene-exposed group (P < 0.05) and was positively associated with the concentration of urinary SPMA (β = 0.103, P = 0.045) and the extent of DNA damage (% Tail DNA: β = 0.181, P = 0.022), but was negatively associated with the leukocyte count (WBC: β = -0.038, P = 0.023). The in vitro study revealed that H3K4me3 mark was enriched in the promoters of several DNA damage responsive (DDR) genes including CRY1, ERCC2, and TP53 in primary human lymphocytes treated with hydroquinone. Particularly, H3K4me3 modification was positively correlated with the expression of CRY1 in the PBLCs of benzene-exposed workers. These observations indicate that H3K4me3 modification might mediate the transcriptional regulation of DDR genes in response to low-dose benzene exposure.

Correlations between Risk Factors for Breast Cancer and Genetic Instability in Cancer Patients-A Clinical Perspective Study

Molecular epidemiological studies have identified several risk factors linking to the genes and external factors in the pathogenesis of breast cancer. In this sense, genetic instability caused by DNA damage and DNA repair inefficiencies are important molecular events for the diagnosis and prognosis of therapies. Therefore, the objective of this study was to analyze correlation between sociocultural, occupational, and lifestyle risk factors with levels of genetic instability in non-neoplastic cells of breast cancer patients. Total 150 individuals were included in the study that included 50 breast cancer patients submitted to chemotherapy (QT), 50 breast cancer patients submitted to radiotherapy (RT), and 50 healthy women without any cancer. Cytogenetic biomarkers for apoptosis and DNA damage were evaluated in samples of buccal epithelial and peripheral blood cells through micronuclei and comet assay tests. Elder age patients (61-80 years) had higher levels of apoptosis (catriolysis by karyolysis) and DNA damage at the diagnosis (baseline damage) with increased cell damage during QT and especially during RT. We also reported the increased frequencies of cytogenetic biomarkers in patients who were exposed to ionizing radiation as well as for alcoholism and smoking. QT and RT induced high levels of fragmentation (karyorrhexis) and nuclear dissolution (karyolysis) and DNA damage. Correlations were observed between age and karyorrhexis at diagnosis; smoking and karyolysis during RT; and radiation and karyolysis during QT. These correlations indicate that risk factors may also influence the genetic instability in non-neoplastic cells caused to the patients during cancer therapies.

Utilização de biomarcadores de genotoxicidade e expressão gênica na avaliação de trabalhadores de postos de combustíveis expostos a vapores de gasolina

Resumo Introdução: a avaliação de uma exposição mensura sua intensidade, frequência e duração, podendo detectar danos precoces que, se ignorados, podem evoluir para um quadro nocivo. Nos campos da saúde ambiental e ocupacional, os biomarcadores de genotoxicidade tem sido largamente utilizados para essa avaliação. Objetivo: identificar, descrever e discutir os principais bioindicadores de genotoxicidade e seu uso conjunto com técnicas de avaliação de expressão gênica em estudos de exposição ocupacional ao benzeno em postos de revenda de combustíveis (PRC). Métodos: revisão bibliográfica de trabalhos publicados entre 1995 e 2015. Resultados: as técnicas identificadas foram: ensaio cometa, estresse oxidativo, micronúcleos, aberrações cromossômicas, polimorfismos, adutos de DNA e proteínas, fatores epigenéticos e expressão gênica. Foi observado que testes de danos genéticos e epigenéticos são utilizados em frentistas de PRC que participam de programas de saúde do trabalhador ou de pesquisas, embora um baixo número de publicações sobre o tema tenha sido identificado. Esse fato talvez possa ser explicado pelos poucos países onde a profissão persiste e pelas limitações para o desenvolvimento de pesquisas nesses países. Conclusão: os bioindicadores de genotoxicidade e as técnicas de expressão gênica são úteis na detecção de dano precoce desta exposição ocupacional e devem ser avaliados em conjunto.

Induced cytotoxic damage by exposure to gasoline vapors: a study in Sinaloa, Mexico

Gasoline is a blend of organic compounds used in internal combustion engines. Gasoline-station attendants are exposed to gasoline vapors, which pose a potentially mutagenic risk. According to the International Agency for Research on Cancer, exposure to gasoline and engine exhaust is possibly carcinogenic to humans. We determined the frequency of micronucleus and other nuclear abnormalities, such as pyknotic nuclei, chromatin condensation, cells with nuclear buds, karyolytic cells, karyorrhexis, and binucleated cells in buccal mucosal smears of 60 gasoline-station attendants and 60 unexposed controls. In addition, we explored if factors such as smoking habits, alcohol consumption, and worked years exert an additional synergistic cytotoxic effect. There were statistically significant higher frequencies (p < 0.05) of nuclear abnormalities among exposed attendants compared to the controls. No statistical significant (p > 0.05) additional effect of lifestyle habits such as smoking and alcohol consumption or worked years on the cytotoxicity was observed. The results showed that from the beginning exposure to gasoline vapors increased the frequency of nuclear abnormalities in buccal epithelial cells. Our results provide valuable information on cytotoxic damage for an early pre-symptomatic diagnosis.

High chromosomal instability in workers occupationally exposed to solvents and paint removers

BACKGROUND

Painters are exposed to an extensive variety of harmful substances like aromatic hydrocarbons used as solvents and paint removers, some of which have shown clastogenic activity. These substances constitute a complex mixture of chemicals which contain well-known genotoxicants, such as Benzene, Toluene and Xylene. Thus, chronic occupational exposure to such substances may be considered to possess genotoxic risk. In Colombia the information available around the genotoxic damage (Chromosomal and DNA damage) in car paint shop workers is limited and the knowledge of this damage could contribute not only to a better understanding of the carcinogenic effect of this kind of substances but also could be used as biomarkers of occupational exposure to genotoxic agents.

RESULTS

In this study, the genotoxic effect of aromatic hydrocarbons was assessed in peripheral blood lymphocytes of 24 workers occupationally exposed and 24 unexposed donors, by using Cytogenetic analysis and comet assay. A high frequency of Chromosomal alterations was found in the exposed group in comparison with those observed in the unexposed group. Among the total of CAs observed in the exposed group, fragilities were most frequently found (100 %), followed by chromosomal breaks (58 %), structural (41.2 %) and numerical chromosomal alterations (21 %). Numerical chromosomal alterations, fragilities and chromosomal breaks showed significant differences between exposed and unexposed groups. Among the fragilities, fra(9)(q12) was the most frequently observed. DNA damage index was also significantly higher in the exposed group compared to the unexposed group (p < 0.000).

CONCLUSIONS

Our results revealed that occupational exposure to aromatic hydrocarbons is significantly associated with Chromosomal and DNA damage in car paint shops workers and are also indicative of high chromosomal instability. The high frequency of both Chromosomal Alterations and DNA Damage Index observed in this study indicates an urgent need of intervention not only to prevent the increased risk of developing cancer but also to the application of strict health control and motivation to the use of appropriate protecting devices during work.

Association between occupational exposure to benzene and chromosomal alterations in lymphocytes of Brazilian petrochemical workers removed from exposure

We aimed to investigate the association between chronic exposure to benzene and genotoxicity in the lymphocytes of workers removed from exposure. The study included 20 workers with hematological disorders who had previously worked in the petrochemical industry of Salvador, Bahia, Brazil; 16 workers without occupational exposure to benzene served as the control group. Chromosomal analysis was performed on lymphocytes from peripheral blood, to assess chromosomal breaks and gaps and to identify aneuploidy. The Kruskal-Wallis test was used to compare the mean values between two groups, and Student's t test for comparison of two independent means. The frequency of gaps was statistically higher in and the exposed group than in the controls (2.13 ± 2.86 vs. 0.97 ± 1.27, p = 0.001). The frequency of chromosomal breaks was significantly higher among cases (0.21 ± 0.58) than among controls (0.12 ± 0.4) (p = 0.0002). An association was observed between chromosomal gaps and breaks and occupational exposure to benzene. Our study showed that even when removed from exposure for several years, workers still demonstrated genotoxic damage. Studies are still needed to clarify the long-term genotoxic potential of benzene after removal from exposure.

Comet assay based DNA evaluation of fuel filling stations and automobile workshops workers from Khyber Pakhtunkhwa province, Pakistan

BACKGROUND

Fuel filling stations workers and automobile workshops mechanics are consistently exposed to gasoline hydrocarbons during their occupation, this may cause DNA damage. Objective of this study was to evaluate the level of DNA damage in subjects occupationally exposed to these hydrocarbons.

METHODS

Comet assay was performed on blood lymphocytes of exposed subjects to assess the probable DNA damage. 100 cells per individual were scored and graded by comet tail length. Exposed group consisted of 98 subjects (age 25.4 ± 7.2 years), of which 68 were CNG/Petrol filling men and 30 were automobile workshop workers, selected randomly from different service stations and automobile workshops of populated and adjacent cities of Peshawar, Mardan and Nowshera of Khyber Pakhtunkhwa province, while control group included 92 subjects (age 26.7 ± 11.8 years) were also from the same areas.

RESULTS

Significantly high level of DNA damage was found in the subjects exposed to gasoline hydrocarbons as compared to control subjects (173.2 ± 50.1 and 61.0 ± 25.0, P = 0.001, respectively). Period of exposure and use of tobacco also showed considerable effects (P < 0.05) on DNA damage, while effect of age and daily working hours on total comet score (TCS) were non-significant (P > 0.05).

CONCLUSIONS

The results of our study concluded that petroleum hydrocarbons have the potential to cause DNA damage in the exposed subjects. The study also suggested that protective strategies should be implemented by the concerned authorities to minimize exposure to fuel hydrocarbons.

SiO2 Nanoparticule-induced size-dependent genotoxicity - an in vitro study using sister chromatid exchange, micronucleus and comet assay

Fine particles with a characteristic size smaller than 100 nm (i.e. nanoparticlesspread out in nowadays life. Silicon or Si, is one of the most abundant chemical elements found on the Earth. Its oxide forms, such as silicate (SiO4) and silicon dioxide, also known as silica (SiO2), are the main constituents of sand and quartz contributing to 90% of the Earth's crust. In this work, three genotoxicity systems "sister chromatid exchange, cytokinesis block micronucleus test and single cell gel electrophoresis (comet) assay" were employed to provide further insight into the cytotoxic and mutagenic/genotoxic potential of SiO2 nanoparticules (particle size 6 nm, 20 nm, 50 nm) in cultured peripheral blood lymphocytes as in vitro. It was observed that there is a significant decrease in Mitotic index (MI), Cytokinesis block proliferation index (CBPI), proliferation index (PRI) values expressed as Cell Kinetic parameters compared with negative control (p < 0.05). There is a statistically significant difference between negative control culture and culture exposed to SiO2 (6 nm, 20 nm, 50 nm) (p < 0.01, p < 0.01, p < 0.05, respectively). It is found that SiO2 nanoparticles at different size (6, 20, 50 nm) progressively increased the SCE frequency and DNA damage on the basis the AU values compared with negative control (p < 0.05). Results showed that the genotoxic/mutagenic and cytotoxic effects of SiO2 nanoparticules is dependent to particule size.

Evaluation of genotoxic effects of benzene and its derivatives in workers of gas stations

The search for reliable biomarkers of human exposure to benzene and its derivatives is still subject of research. Many of the proposed biomarkers have limitations ranging from the low sensitivity to the wide variability of results. Thus, the aim of our study was to assess the frequencies of chromosomal abnormalities (CA) and sister chromatid exchanges (SCE) in workers of gas stations, with (cases, n = 19) and without (local controls, n = 6) risk of exposure to benzene and its derivatives, comparing them with the results from the general population (external controls, n = 38). The blood dosages of benzene, toluene, and xylenes were measured in all participants. Blood solvent levels were compared with the findings obtained in cytogenetic evaluation and a research protocol which included data of the workplace, lifestyle, and health of the individuals. We did not detect the presence of benzene and its derivatives and did not find chromosomal damage that may be associated with the gas station activity in cases. Moreover, although we found an association of increased SCE and the working time in the local controls, the values found for SCE are within normal limits. Thus, our evaluation of SCE and CA reflected the levels of benzene and its derivatives observed in the blood. We believe, therefore, that SCE and CA may actually constitute possible tests for the evaluation of these exposures. However, we believe that further studies, including individuals at risk, are important to confirm this assertion.

Determination of genetic damage and urinary metabolites in fuel filling station attendants

Fuel (diesel and petrol) constitutes a complex mixture of volatile flammable liquid hydrocarbons among them benzene (BZ), toluene (TOL), and xylene (XYL) are considered to be the most hazardous, predominantly BZ because of its carcinogenic potency. Exposure to these compounds may have an impact on the health of the exposed subjects. Hence, genotoxicity and quantitative analysis of these compounds was performed in blood and urine samples of 200 workers exposed to fuel in filling stations and compared to controls. The level of genetic damage was determined by micronucleus test (MNT) in buccal epithelial cells (BEC) and chromosomal aberrations (CA) assay in peripheral blood lymphocytes (PBL) of fuel filling station attendants (FFSA) and compared to a matched control group. Urine analysis for BZ and its metabolites, phenol (Ph), trans, trans-Muconic Acid (t, t-MA), and S-Phenyl Mercapturic Acid (S-PMA) was done in all the study subjects. The results of our study revealed that exposure to BTX in petrol vapors induced a statistically significant increase in the frequency of micronuclei (MN) and CA in the exposed subjects than in controls (P < 0.05). There was a significant rise in the levels of urinary BZ, Ph, t, t-MA, and S-PMA in the exposed subjects. Our study highlights the significance of MNT, CA, and urinary metabolites as potential biological exposure indices of genetic damage in FFSA. This study suggests the need for regular monitoring of FFSA for possible exposure to BTX as a precautionary and preventive step to minimize exposure and reduce the associated health risks.

Protective role of grape seed extract against doxorubicin-induced cardiotoxicity and genotoxicity in albino mice

In this study, the protective role of grape seed extract (GSE) against doxorubicin (DOX)-induced cardiotoxicity and genotoxicity has been evaluated in male Mus musculus var. albino mice. The micronucleus (MN) test in erythrocytes and the chromosome aberration (CA) test in bone marrow cells were used. Also, levels of reduced glutathione (GSH) and lipid peroxidation as malondialdehyde (MDA) in heart homogenates were measured, and in addition the changes in heart histology were investigated. The mice were randomly divided into six groups. Group I (negative control) received intraperitoneal injections of isotonic saline (0.02 mL/g) for 6 consecutive days, Group II received intraperitoneal injections of DOX (2.5 mg/kg of body weight, six doses every other day; cumulative dosage, 15 mg/kg of body weight) for 6 consecutive days, Group III received GSE (50 mg/kg of body weight, 21 doses every other day; cumulative dosage, 1,050 mg/kg of body weight) for 21 consecutive days, Group IV received GSE (150 mg/kg of body weight, 21 doses every other day; cumulative dosage, 3,150 mg/kg of body weight) for 21 consecutive days, Group V received GSE (50 mg/kg of body weight, 28 doses every other day; cumulative dosage, 1,400 mg/kg of body weight) for 28 consecutive days plus DOX (2.5 mg/kg of body weight, six doses every other day; cumulative dosage, 15 mg/kg of body weight) for 6 consecutive days, and Group VI received GSE (150 mg/kg of body weight, 28 doses every other day; cumulative dosage, 4,200 mg/kg of body weight) for 28 consecutive days plus DOX (2.5 mg/kg of body weight, six doses every other day; cumulative dosage, 15 mg/kg of body weight) for 6 consecutive days. DOX induced heart damage as indicated from a pronounced change in heart histology. In the DOX-treated group, there was a significant increase in MDA content in the heart homogenate, and the level of GSH was significantly decreased. DOX induced genotoxicity by increasing the number of aberrant metaphases (AMNs), MNs, and structural chromosomal aberrations (CAs) such as chromatid breaks, dicentrics, acentric fragments, and gaps and showed a detractive effect on the mitotic index (MI) of cells. Pretreatment with GSE before treatment with DOX significantly protected the heart tissue by ameliorating its antioxidant activity. In Groups V and VI, the MDA level of heart tissue was significantly decreased, and the GSH level was increased compared to the DOX-treated group. Moreover, GSE significantly protected bone marrow chromosomes from DOX-induced genotoxicity by reducing the total AMNs and the frequency of structural CAs. GSE treatment also decreased the frequency of MNs and increased the MI values. It could be concluded that GSE acts as a potent antioxidant to prevent heart damage and genotoxicity of bone marrow cells.

Assessment of occupational cytogenetic risk, among petrol station workers

The focal aim of this study was to assess the frequency of chromosomal aberrations (CA) including chromatid type aberrations (CTA) and chromosomal type aberrations (CSA), micronucleus (MN) and XRCC1 399 Arg/Gln polymorphism in the peripheral blood lymphocytes of 27 petrol pump workers and same number of controls to explore the possible cytogenetic risk on occupational exposure to petrol vapors. The exposed subjects and controls were classified into two groups based on their age (group I < 40 years; group II > 40 years) apart from the classification of the exposed subjects based on their exposure duration (> 8 and < 8 years). CTA and MN frequency were significantly higher in petrol pump workers (p < 0.05) with longer work duration. CTA was found to increase with age in the exposed subjects as well as controls, with exposed subjects showing a statistically higher degree. This effect was not observed in MN. A significantly higher frequency of MN was observed in the smoking petrol pump workers than in control smokers (p < 0.05). No association was found between smoking and CA in both subjects. The study on XRCC1 399 Arg/gln polymorphism in petrol pump workers demonstrated very less difference in allele frequency compared to controls. In conclusion, these datas indicate that petrol pump workers under risk group should be monitored for any long-term adverse effects of the exposure.

Assessment of genetic damage in buccal epithelium cells of painters: micronucleus, nuclear changes, and repair index

The micronucleus (MN) assay in exfoliated buccal cells is a useful and minimally invasive method for monitoring genetic damage in humans exposed to occupational and environmental agents. The MN test is used as an indicator of genotoxic exposition, since it is associated with chromosome aberrations. An increased mutation rate in oral squamous cells, which is indicated by an increased MN frequency, is also related to the development of oral mucosa diseases, such as carcinomas. We evaluated MN frequencies and other nuclear changes (NCs), karyorrhexis (KR), karyolysis (KL), broken egg (BE), and binucleus in buccal mucosa cells of 60 painters (30 smokers and 30 nonsmokers) and 60 healthy control subjects (30 smoker and 30 nonsmoker). Microscopic observation of 3000 cells per individual was performed in both painters and control subjects. In the control group and the exposed group, for each person repair index (RI) was calculated via the following formula: (KR + KL)/(BE + MN). The results showed a statistically significant increase in the frequency of MN in buccal epithelial cells of the exposed group compared with the control group (p < 0.05). Smokers and nonsmokers differed with respect to the incidence of MN and NCs in all groups. In painters, RI was less than that in the control group. There was a significant difference between painters and the control group (p < 0.01) for RI. We believe that determination of RI in addition to NCs and the MN will present a new approach to genotoxicity studies of a population.

Royal jelly (honey bee) is a potential antioxidant against cadmium-induced genotoxicity and oxidative stress in albino mice

Cadmium (Cd) is a highly toxic heavy metal that induces genotoxic damage in the body. Besides, Cd induces oxidative damage in various tissues by altering antioxidant defence enzymes system. In this study, we investigated the protective role of royal jelly (RJ) on Cd-induced genotoxicity and oxidative stress in mice. For this aim, the micronucleus (MN) test in erythrocytes and exfoliated cells of buccal mucosa and the chromosome aberration (CA) test in bone marrow cells were applied. In addition, the levels of reduced glutathione (GSH) and malondialdehyde (MDA) were evaluated in the liver and kidneys. Thirty-six animals were divided into six groups: the control group received distilled water alone, whereas mice in the treatment groups received RJ alone (100 and 250 mg/kg of body weight), Cd alone (2 mg/kg of body weight), and RJ+Cd. Cd toxicity resulted in a significant (P < .05) increase in CAs, abnormal metaphase number, and MN formation. Cd also caused a decrease in mitotic index. Oral administration of RJ at two doses (100 and 250 mg/kg of body weight) showed significant (P < .05) suppression of mutagenic effects of Cd. Moreover, Cd-induced oxidative damage caused a significant decrease in GSH level and a significant increase in MDA level in the liver and kidneys. Treatment with two doses of RJ caused a significant recovery in antioxidant status of GSH and a significant inhibition of MDA production. It could be concluded that RJ has a protective role against Cd-induced genotoxicity and oxidative stress in mice, due to its antioxidant effects.

Frequency of chromosomal aberrations in peripheral lymphocytes of tannery workers in Brazil

To evaluate the incidence of chromosomal aberrations (CA) in peripheral lymphocytes of workers chronically exposed to chemical hazards in a tannery in Franca, São Paulo, Brazil. The exposed group consisted of 10 male workers employed in the same tannery. The duration of work in the tannery ranged from 5 months to 14 years. The control group consisted of 10 males without a history of exposure to chemicals or other potentially genotoxic substances. A total of 100 well-spread metaphases were analyzed per subject. The frequency of CA was higher in the exposed group than in the control group. Smoking had a significant effect on the frequency of CA in both the control and the exposed groups. Chronic occupational exposure of tannery workers represents a relevant risk factor for the development of diseases associated with genetic damage.

Toxicity and genotoxicity of wastewater from gasoline stations

The toxicity and genotoxicity of wastewater from eight gasoline stations in Brasília, Brazil's capital city, was studied by assessing chromosomal aberrations, chromosomal malsegregation and the mitotic index in Alliumcepa root cells, and the occurrence of micronucleus and nuclear abnormalities in peripheral erythrocytes of tilapia fish (Oreochromis niloticus). The content of gasoline station effluents was also analyzed based on several physico-chemical parameters. None of the wastewater samples was genotoxic to A. cepa root cells, although cell proliferation was significantly inhibited, especially at the highest concentrations. Likewise, no micronuclei were observed in O. niloticus peripheral erythrocytes, even after exposure to high concentrations, but there was an increase in the number of nuclear abnormalities and fish mortality. These results show that although the effluent from gasoline stations is processed by an oil/water separation system before being discharged into the main sewage system, the wastewater still contains toxic compounds.

The Frequency of Sister Chromatid Exchanges in Cultured Human Peripheral Blood Lymphocyte Treated with Metronidazolein Vitro

5-Nitroimidazoles are a group of antiprotozoal and antibacterial agents. Thanks to their antimicrobial activity, these chemotherapeutic agents inhibit the growth of both anaerobic bacteria and certain anaerobic protozoa. One of the useful drugs used in the treatment of infections caused by Trichomonas vaginalis, Entamoeba histolytica, and Giardia lamblia is metronidazole (MTZ). The mutagenicity of metronidazole [1-(hydroxyethyl)-2-methyl-5-nitroimidazole] has been previously shown in different prokaryotic systems but not in eukaryotic systems. The objective of this study is to determine the mutagenic and cytotoxic effects of MTZ at plasma concentration and higher in vitro. In this study, we evaluated the mutagenicity and cytotoxicity of MTZ in cultured human peripheral blood lymphocytes. Doses were selected according to plasma concentration of drug. End points analyzed included mitotic index (MI), replication index (RI), and sister chromatid exchange (SCE). An analysis of variance test (ANOVA) was performed to evaluate the results. A significant decrease (p < 0.001) in MI and RI as well as an increase in SCE frequency (p < 0.001) was observed compared with control cultures. Our results indicate the genotoxic and cytotoxic effect of MTZ in cultured human peripheral blood lymphocytes at plasma concentrations slightly higher than encountered therapeutically.

Genotoxic biomonitoring study of population residing in pesticide contaminated regions in Göksu Delta: micronucleus, chromosomal aberrations and sister chromatid exchanges

Pesticides are widely used throughout the world in agriculture to protect crops and in public health to control diseases. Nevertheless, exposure to pesticides represents a potential risk to humans. This paper describes a study of possible genetic damage in the people living in regions contaminated with complex mixture of pesticides in Göksu Delta. In this study, used methods were chromosomal aberration (CA), sister chromatid exchange analysis (SCE) in the peripheral blood lymphocytes, and micronucleus (MN) assay in the buccal epithelial cells. In the present investigation, 32 affected subjects consist of 16 smoking and 16 non-smokings and an equal number of control subjects were assessed for genome damage. Micronucleus (MN), Broken egg (BE), Karyorrhexis (KR), Karyolysis (KL) and Binucleus (BN) frequencies were higher in affected subjects than in controls. Smoking had a statistically significant effect on the Micronucleus, Karyorrhexis and Binucleus frequencies for both the control and the exposed group. Also smoking and exposure affected the frequency of sister chromatid exchange and chromosomal aberrations compared with control groups.

Benzene's toxicity: a consolidated short review of human and animal studies

A large population of humans is exposed to benzene from various occupational and environmental sources. Benzene is an established human and animal carcinogen. Exposure to benzene has been associated with leukaemia in humans and several types of malignancies in animals. The exact mechanism of benzene-induced toxicity is poorly understood. It is believed that benzene exerts its adverse effects by metabolic activation to toxic metabolites. Certain benzene metabolites are genotoxic and mutagenic. This consolidated short-review is composed of human and animal studies to summarize the adverse effects of benzene with special reference to molecular mechanisms involved in benzene-induced toxicity.

White blood cell sister chromatid exchange among a sample of Thai subjects exposed to toluene, an observation

There is a particular concern with toluene because some research has indicated that toluene exposure could result in chronic toxicity including mutagenesis and carcinogenesis. This study aimed to determine the rate of sister chromatid exchanges (SCE), a marker for genotoxicity, and its correlation to the classical urine biomarker for toluene exposure, urine hippuric acid, among a sample of Thai exposed subjects. A total of 26 police (all males) were included in this study. The average (mean +/- SD) urine hippuric acid level in these police was 0.8 +/- 0.4 mg/g creatinine. The average (mean +/- SD) SCE level in these police was 4.5 +/- 1.0/cell. The average SCE among the police with high urine hippuric acid levels was non-significantly higher than the average SCE level of those without (P = 0.41). This implies that the cytogenetic response to toluene was not different between the subjects with and without high toluene exposure. High exposure to toluene seems not to be related to high SCE.

Genotoxicity of occupational exposure to wood dust: Micronucleus frequency and nuclear changes in exfoliated buccal mucosa cells

Occupational exposure to wood dust is associated with the occurrence of nasal cancer. In this study, we investigated micronuclei and nuclear changes (NCs: binucleates, karyorrhexis, karyolysis, and the "broken egg" effect) in exfoliated buccal cells of 20 workers exposed to wood dust and 20 age- and sex-matched controls. Micronucleus frequency and the frequency of each of the NCs were significantly higher for wood workers than controls (P < 0.01). Cigarette smoking was associated with increased frequencies of micronuclei and NCs in the buccal mucosa epithelium cells of both the control and exposed groups. Our findings indicate that buccal cells of wood workers display increased levels of genotoxicity and toxicity, and that these biomarker responses may be related to the increased cancer risk among wood workers.

Evaluation of cytotoxic and mutagenic effects of Coriolus versicolor and Funalia trogii extracts on mammalian cells

This study examined the in vitro cytotoxic activities of standardized aqueous bioactive extracts prepared from Coriolus versicolor and Funalia trogiiATCC 200800 on HeLa and fibroblast cell lines using a MTT (3-[4,5-dimetiltiazol-2-]-2-5-difeniltetrazolium bromide) cytotoxicity assay. F. trogii and C. versicolor extracts were cytotoxic to both cell lines. At 10 microL treatment level, F. trogii and C. versicolor extracts inhibited proliferation of HeLa cancer cells by 71.5% and 45%, respectively, compared with controls. Toxicity was lower toward normal fibroblasts. In the latter case, treatment at 10 microL level with F. trogii and C. versicolor extracts reduced cell proliferation by 51.3% and 38.7%, respectively. In separate experiments, the mitotic index (MI) obtained with 3 microL treatment level of unheated extracts of the two fungi was comparable to the MI value obtained by treatment with 4 microg/mL MMC (anticancer agent mitomycin-C). A significant induction of sister chromatid exchange (SCE) was observed in normal cultured lymphocytes treated with MMC (4 microg/mL). MMC treatment reduced replication index compared with treatment with unheated F. trogii extract and negative controls (p < 0.001). In contrast to MMC, F. trogii extracts did not affect the proliferation of human lymphocytes compared with controls (p > 0.05). Laccase and peroxidase enzyme activities in F. trogii extract were implicated in their inhibitory effect on cancer cells. F. trogii extract was concluded to have antitumor activity.

Occupational exposure in airport personnel: characterization and evaluation of genotoxic and oxidative effects

Airport personnel can be exposed to several polycyclic aromatic hydrocarbons (PAHs) from jet fuel vapours, jet fuel combustion products and diesel exhaust. The aim of this study was to characterize the exposure and to evaluate genotoxic and oxidative effects in airport personnel (n=41) in comparison with a selected control group (n=31). Environmental monitoring of exposure was carried out analysing 23 PAHs on air samples collected from airport apron, airport building and terminal/office area during 5 working days. The urinary 1-hydroxy-pyrene (1-OHP) following 5 working days, was used as biomarker of exposure. Genotoxic effects and early direct-oxidative DNA damage were evaluated by micronucleus (MN) and Fpg-modified comet assay on lymphocytes and exfoliated buccal cells, and by chromosomal aberrations (CA) and sister chromatid exchange (SCE) analyses. For comet assay, tail moment (the product of comet relative tail intensity and length) values from Fpg-enzyme treated cells (TMenz) and from untreated cells (TM) were used as parameters of oxidative and direct DNA damage, respectively. We found 27,703 microg/m(3) total PAHs in airport apron, 17,275 microg/m(3) in airport building and 9,494 microg/m(3) in terminal/office area. Urinary OH-pyrene did not show differences between exposed and controls. The exposed group showed a higher mean value of SCE frequency in respect to controls (4.6 versus 3.8) and an increase (1.3-fold) of total structural CA in particular breaks (up to 2.0-fold) and fragments (0.32% versus 0.00%), whereas there were no differences of MN frequency in both cellular types. Comet assay evidenced in the exposed group a higher value in respect to controls of mean TM and TMenz in both exfoliated buccal cells (TM 118.87 versus 68.20, p=0.001; TMenz 146.11 versus 78.32, p<0.001) and lymphocytes (TM 43.01 versus 36.01, p=0.136; TMenz 55.86 versus 43.98, p=0.003). An oxidative DNA damage was found, for exfoliated buccal cells in the 9.7% and for lymphocytes in the 14.6% of exposed in respect to the absence in controls. Our findings furnish a useful contribution to the characterization of civil airport exposure and suggest the use of comet assay on exfoliated buccal cells to assess the occupational exposure to mixtures of inhalable pollutants at low doses since these cells represent the target tissue for this exposure and are obtained by non-invasive procedure.