In vitro genomic damage induced by urban fine particulate matter on human lymphocytes.

Urban air pollution represents a global problem, since everyday many mutagenic and carcinogens compounds are emitted into the atmosphere, with consequent adverse health effects on humans and biota. Specifically, particulate matter air pollution was associated with increased risks in human mortality and morbidity. In this paper, we analyse the genomic effects on human lymphocytes of different concentrations of annual Turin PM2.5 extract by an in vitro micronuclei assay. Samplings were collected from an urban meteorological-chemical station positioned in Turin (Italy), one of the most polluted cities in Europe. PM2.5 sampled on filters was used for organic extraction in monthly pools and successively aggregated to produce a mixture representative for a full year PM2.5 collection. Lymphocytes were exposed to four concentrations of PM2.5: 5, 10, 15 and 20 µg/mL and micronuclei, nucleoplasmic bridges and nuclear buds were scored. With respect to controls, PM2.5 significantly increased the frequencies of all analysed biomarkers at all tested concentrations, whereas the CBPI index was significantly reduced only at the concentration of 20 µg/mL. Such in vitro effects can both to stimulate local authorities to adopt efficient measures for air pollution mitigation and to improve human monitoring to detect early precancer lesions.

Morphology of planktonic zoeal stages of Palicus caronii (Decapoda, Brachyura), identified by DNA barcoding, provides novelties to Palicoidea larval systematics.

The zoeal development of the brachyuran crab, Palicus caronii, comprises two zoeal stages and the morphology is described and illustrated in detail. The zoeae were collected in plankton samples from the Southern Ligurian Sea (Western Mediterranean). Although the morphology of the larval stages of this species was unknown, a combination of characters allowed the zoeae to initially be assigned to the Palicidae, based on the previous unique known first zoeal description of one species of this family. Later, the identification of the larvae as Palicus caronii was confirmed through molecular analysis. The morphological features of the zoeae that characterize the Palicidae and separate them from the Crossotonotidae are confirmed. Also, the larval development comprising only two zoeal stages observed in Palicus caronii, the peculiar and uncommon carapace surface setation, and the presence of anterodorsal and posterodorsal sensory dorsal organs suggest that these characters could be common to the Palicoidea.

Induction of chromosomal aberrations and micronuclei by 2-hydroxy-4-methoxybenzophenone (oxybenzone) in human lymphocytes.

Oxybenzone or benzophenone-3 (2-hydroxy-4-methoxybenzophenone; BP-3) is a filter used in a variety of personal care products for protection of human skin and hair from damage by ultraviolet radiation. BP-3 is suspected to exhibit endocrine disruptive properties. Indeed, it was found to be able to interact with the endocrine system causing alteration of its homeostasis, with consequent adverse health effects. Moreover, it is ubiquitously present in the environment, mostly in aquatic ecosystems, with consequent risks to the health of aquatic organisms and humans. In the present study, we analyzed the cytogenetic effects of BP-3 on human lymphocytes using in vitro chromosomal aberrations and micronuclei assays. Blood samples were obtained from five healthy Italian subjects. Lymphocyte cultures were exposed to five concentrations of BP-3 (0.20, 0.10, 0.05, 0.025, and 0.0125 µg/mL) for 24 and 48 h (for chromosomal aberrations and micronuclei tests, respectively). The concentration of 0.10 µg/mL represents the acceptable/tolerable daily intake reference dose established by European Union, whereas 0.20, 0.05, 0.025, and 0.0125 µg/mL represent multiple and sub-multiple of this concentration value. Our results reported cytogenetic effects of BP-3 on cultured human lymphocytes in terms of increased micronuclei and chromosomal aberrations' frequencies at all tested concentrations, including concentrations lower than those established by European Union. Vice versa, after 48-h exposure, a significant reduction of the cytokinesis-block proliferation index value in cultures treated with BP-3 was not observed, indicating that BP-3 does not seem to produce effects on the proliferation/mitotic index when its concentration is equal to or less than 0.20 µg/mL.

In vitro evaluation of genomic damage induced by glyphosate on human lymphocytes.

Glyphosate is an important broad-spectrum herbicide used in agriculture and residential areas for weed and vegetation control, respectively. In our study, we analyzed the in vitro clastogenic and/or aneugenic effects of glyphosate by chromosomal aberrations and micronuclei assays. Human lymphocytes were exposed to five glyphosate concentrations: 0.500, 0.100, 0.050, 0.025, and 0.0125 µg/mL, where 0.500 µg/mL represents the established acceptable daily intake value, and the other concentrations were tested in order to establish the genotoxicity threshold for this compound. We observed that chromosomal aberration (CA) and micronuclei (MNi) frequencies significantly increased at all tested concentrations, with exception of 0.0125 µg/mL. Vice versa, no effect has been observed on the frequencies of nuclear buds and nucleoplasmic bridges, with the only exception of 0.500 µg/mL of glyphosate that was found to increase in a significant manner the frequency of nucleoplasmic bridges. Finally, the cytokinesis-block proliferation index and the mitotic index were not significantly reduced, indicating that glyphosate does not produce effects on the proliferation/mitotic index at the tested concentrations.

Genomic damage induced by the widely used fungicide chlorothalonil in peripheral human lymphocytes.

Chlorothalonil is an important broad spectrum fungicide widely used in agriculture, silviculture, and urban settings. As a result of its massive use, chlorothalonil was found in all environmental matrices, with consequent risks to the health of terrestrial and aquatic organisms, as well as for humans. We analyzed the effects of chlorothalonil on human lymphocytes using in vitro chromosomal aberrations (CAs) and micronuclei (MNi) assays. Lymphocytes were exposed to five concentrations of chlorothalonil: 0.600 µg/mL, 0.060 µg/mL, 0.030 µg/mL, 0.020 µg/mL, and 0.015 µg/mL, where 0.020 and 0.600 µg/mL represent the ADI and the ARfD concentration values, respectively, established by FAO/WHO for this compound; 0.030 and 0.060 µg/mL represent intermediate values of these concentrations and 0.015 µg/mL represents the ADI value established by the Canadian health and welfare agency. We observed cytogenetic effects of chlorothalonil on cultured human lymphocytes in terms of increased CAs and MNi frequencies at all tested concentrations, including the FAO/WHO ADI and ARfD values of 0.020 and 0.600 µg/mL, respectively, but with exception of the Canadian ADI value of 0.015 µg/mL. Finally, no sexes differences were found in the levels of CAs and MNi induced by different chlorothalonil concentrations. Similarly, the mitotic index and the cytokinesis-block proliferation index did not show any significant effect on the proliferative capacity of the cells, although at the chlorothalonil concentration of 0.600 µg/mL the P-values of both indices were borderline.

Evaluation of baseline frequency of sister chromatid exchanges in an Italian population according to age, sex, smoking habits, and gene polymorphisms.

OBJECTIVES: Increased SCEs frequencies in human lymphocytes are an indicator of spontaneous chromosome instability and could be influenced by different exogenous and endogenous factors. In this study, we evaluated the influence of age, sex, smoking habits, and genetic polymorphisms on the background levels of SCEs in peripheral blood lymphocytes. METHODS: Two hundred-thirty healthy Italian subjects were recruited. Data about age, sex and smoking habits were recorded. Subjects were also genotyped for GSTT1, GSTM1, GSTP1 A/G, CYP1A1 Ile/Val, CYP2C19 G/A, ERCC2/XPD Lys751Gln, XRCC1 Arg194ATrp, XRCC1 Arg399Gln, and XRCC1Arg208His gene polymorphisms. RESULTS: The frequency of SCEs/cell was 5.15 ± 1.87, with females showing a significantly higher SCEs value with respect to males (5.36 ± 2.10 and 4.82 ± 1.39, respectively). Smokers showed significantly increased levels of SCEs with respect to nonsmokers (5.93 ± 1.75 and 4.70 ± 1.79, respectively) whereas no differences were observed between heavy and light smokers. Age correlated with the RI value (P = .01) but not with the SCEs frequency (P = 07), although the 31-40 age group showed a significantly lower SCEs frequency with respect to the other age groups. A significant association was also found between GSTP2C19-AA, GSTT1-null, GSTM1-null, ERCC2/XPD Gln751Gln, and XRCC1 His208His genotypes, and higher frequencies of SCEs. CONCLUSION: We describe the association between some phase I, phase II, and DNA-repair gene polymorphisms with increased SCEs frequencies, reinforcing the importance of genetic analysis in biomonitoring studies. Sex and age were found to be important endogenous factors that affect the level of genomic damage and the replicative capacity of cells, respectively.

Association of GSTT1 null, XPD 751 CC and XPC 939 CC genotypes with increased levels of genomic damage among hospital pathologists.

CONTEXT: Hospital workers are at risk for genotoxic damage following occupationally exposure to xenobiotics. Pathologists are exposed to chemicals during their use in health care environments, particularly throughout inhalation of airborne agents, absorption through skin or contact with the patient's body fluids. OBJECTIVE: We evaluated the level of genomic damage in a sample of 61 hospital pathologists (occupationally exposed to antineoplastic drugs and sterilizing agents) and 60 control subjects. MATERIALS AND METHODS: Lymphocytes were analyzed by SCEs and CAs assays and genotyped for GSTT1, GSTM1, CYP1A1 Ile/Val, XPD (A751C) and XPC (A939C) gene polymorphisms. RESULTS: Pathologists showed significantly higher frequencies of SCEs and CAs with respect to control subjects. GSTT1 null genotype was found to be associated with higher SCEs and CAs frequencies, whereas XPD 751 CC and XPC 939 CC genotypes only with a higher level of SCEs. DISCUSSION AND CONCLUSIONS: The SCEs and CAs results are consistent with other published data, placing hospital workers as a category at risk for genotoxic damage caused by chronic exposure to xenobiotics. The higher levels of cytogenetic damage observed among GSTT1 null, XPD 751 and XPC 939 CC homozygote subjects confirm the importance of the genetic polymorphisms analysis associated to genotoxicological studies.

Relationships between cytokine (IL-6 and TGF-ß1) gene polymorphisms and chromosomal damage in hospital workers.

Cytokine gene polymorphisms have been found to be associated with a pre-disposition to a variety of diseases, including inflammatory and cancer diseases. The present study evaluated the influence of six cytokine gene polymorphisms on the level of genomic damage observed in peripheral blood lymphocytes from hospital pathologists chronically exposed to low doses of different xenobiotics. Lymphocytes from 50 pathologists and 50 control subjects were recruited and analyzed in Sister Chromatid Exchange (SCE) and Chromosomal Aberrations (CA) assays. The frequencies of six cytokine gene polymorphisms and their relationships with the cytogenetic damage levels were also evaluated. The results indicated that significant differences were found between pathologists and controls in terms of SCE frequency (p < 0.001) and RI values (p < 0.001), as well as in terms of CA and cells with aberrations (p < 0.001). No associations were found between all analyzed cytokine gene polymorphisms and CA frequency in both pathologists and control groups. Vice versa, among pathologists, homozygote individuals for the IL-6 G allele showed a significantly (p = 0.017) lower frequency of SCE with respect to heterozygote subjects. Similarly, for TGFß1 codon 10 locus, homozygote for T allele and heterozygote TC subjects showed a significantly (p = 0.021) lower frequency of SCE with respect to homozygote CC individuals. Among controls, no significant differences were found in the frequency of SCE between genotypes at all loci. Based on these results, we speculate that high circulating levels of a pro-inflammatory cytokine like IL-6 and lower levels of the immunosuppressant cytokine TGFß1 could be associated directly with a longer duration and/or greater intensity of inflammatory processes, and indirectly with significantly higher levels of genomic damage.

Baseline frequency of chromosomal aberrations and sister chromatid exchanges in peripheral blood lymphocytes of healthy individuals living in Turin (North-Western Italy): assessment of the effects of age, sex and GSTs gene polymorphisms on the levels of genomic damage.

BACKGROUND: The increased exposure to environmental pollutants has led to the awareness of the necessity for constant monitoring of human populations, especially those living in urban areas. AIM: This study evaluated the background levels of genomic damage in a sample of healthy subjects living in the urban area of Turin (Italy). The association between DNA damage with age, sex and GSTs polymorphisms was assessed. SUBJECTS AND METHODS: One hundred and one individuals were randomly sampled. Sister Chromatid Exchanges (SCEs) and Chromosomal Aberrations (CAs) assays, as well as genotyping of GSTT1 and GSTM1 genes, were performed. RESULTS: Mean values of SCEs and CAs were 5.137 ± 0.166 and 0.018 ± 0.002, respectively. Results showed age and gender associated with higher frequencies of these two cytogenetic markers. The eldest subjects (51-65 years) showed significantly higher levels of genomic damage than younger individuals. GSTs polymorphisms did not appear to significantly influence the frequencies of either markers. CONCLUSION: The CAs background frequency observed in this study is one of the highest reported among European populations. Turin is one of the most polluted cities in Europe in terms of air fine PM10 and ozone and the clastogenic potential of these pollutants may explain the high frequencies of chromosomal rearrangements reported here.

Evaluation of Genomic Damage in Peripheral Lymphocytes from Occupationally Exposed Anesthetists: Assessment of the Effects of Age, Sex, and GSTT1 Gene Polymorphism.

Occupational exposure to anaesthetic gases is one of the major hazards to healthcare personnel. We evaluated the cytogenetic effects of chronic exposure to low concentrations of anaesthetic gases in operating theatres. The study included 21 anesthetists and 21 control subjects who matched in age and gender. Chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) assays were performed. All subjects were also genotyped for glutathione S-transferase T1 (GSTT1) gene polymorphisms. Significant differences were found between exposed and controls in terms of SCEs frequency (P = 0.001) and replication index value (P = 0.005), but not in terms of CAs (P = 0.201) and aberrant cells (P = 0.227) frequencies. Regression analyses indicated that age and the years of employment did not influence the level of chromosomal damage in both groups. Finally, among anesthetists, GSTT1 null individuals showed a significant higher frequency of SCE with respect to GSTT1-positive subjects.

Evidence of genotoxicity in lymphocytes of non-smoking alcoholics.

Alcohol abuse is a significant public health issue. Epidemiological studies conducted on different populations consistently showed that consumption of alcoholic beverages is associated with cytogenetic damages and higher risk for several types of cancer. However, the interpretation of many cytogenetic studies resulted complicated because some confounding factors, such as smoking habit, are not always taken into account. In the present study, the frequency of sister chromatid exchanges (SCEs), chromosome aberrations (CAs) and micronuclei (MNs) in cultured human lymphocytes was assessed on 15 alcoholic and 15 non-alcoholic control male subjects. Moreover, considering the implication of the Glutathione S-transferases gene polymorphisms in the genetic susceptibility to alcoholic liver diseases, we considered an important issue to evaluate the relationship between these gene polymorphisms and the cytogenetic damage. In our sample we exclusively considered individuals that did not smoke nor consume drugs for a period of at least 2 years prior to the analysis. Statistically significant differences were found between alcoholics and controls in the frequency of SCEs/cell (P = 0.001), RI value (P = 0.001), CAs (P = 0.002) and CAB (P = 0.002). Vice versa, no significant differences were found between alcoholics and controls in terms of MNs frequency and CBPI value. In both samples, no statistically significant association was found between the analysed GSTs gene polymorphisms and the frequencies of MNs, SCEs and CAs. Finally, among alcoholics we found a positive correlation between SCEs and CAs frequencies and the duration of alcohol abuse.

Evaluating the genotoxicity of urban PM2.5 using PCR-based methods in human lung cells and the Salmonella TA98 reverse test.

A number of compounds found in particulate matter with an aerodynamic diameter <2.5 (PM2.5) can interact with DNA either directly or after enzymatic transformation to induce DNA modifications. These particulate matter (PM)-induced alterations in DNA may be associated with increased frequencies of pollution-associated diseases, such as lung cancer. In the present study, we applied different methods to assess the mutagenicity and genotoxicity of monthly PM2.5 organic extracts collected over a full year. We used the Salmonella assay, exposed cultured human embryonic lung fibroblasts and applied extracellular lactate dehydrogenase (LDH) and 2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxyanilide inner salt (XTT) assays to assess the cytotoxicity of PM2.5 on the cells. We assessed both the expression levels of a number of DNA repair genes (using qRT-qPCR) and the genetic profile of the treated cells compared to the control. The expression levels of XRCC1 and APE1, which are involved in the first steps of base excision repair, as well as ERCC1, XPA and XPF, which encode nucleotide excision repair subunits, were analysed. The monthly mean of the PM2.5 collected was 35.16 ± 22.06 µg/m(3). The mutagenicity of PM2.5 to TA98 was 46 ± 50 net revertants/m(3), while the mutagenicity to TA98 + S9 was 17 ± 19 net revertants/m(3). The mean IC50 values were 2.741 ± 1.414 and 3.219 ± 2.764 m(3) of equivalent air in the XTT and LDH assays, respectively. A marked and significant increase in APE1 expression levels was observed in the exposed cells. This effect was also significantly correlated with mutagenicity (p < 0.01). No induced AFLP fragment profile alterations were detected. The proposed approach seems to be useful for integrated evaluation and for highlighting the mechanisms inducing DNA damage.

Increased frequency of chromosomal aberrations and sister chromatid exchanges in peripheral lymphocytes of radiology technicians chronically exposed to low levels of ionizing radiations.

Chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) frequencies were estimated in peripheral lymphocytes from 21 radiology technicians, and from 21 non-exposed control subjects. We exclusively considered individuals who neither smoke nor consume drugs or alcohol for a period of at least two years prior to the analysis. Significant differences were found between exposed and controls in terms of SCEs and CAs frequencies. Technicians showed a significant higher number of high-frequency individuals (HFIs) with respect to the control group. Nevertheless, the mean frequency of SCEs observed among technician HFIs did not significantly differ with respect to that observed among control HFIs. Vice versa, the non-HFIs belonging to technicians group showed a statistically higher difference in the SCEs/NSM value with respect to the non-HFIs belonging to control group. Since the differences in the SCEs frequencies between the two groups are due to non-HFIs, our results seem to indicate a general genotoxic effect of the IR, not affected by HFIs. Among technicians, the level of chromosome damage correlated neither with years of radiation exposure nor with the age of the subjects. Vice versa, in the control group, a positive correlation was found between the number of SCEs and age. In both samples the gender status did not influence the frequencies of CAs and SCEs. Our results suggest that chronic long-term exposure to low doses of ionizing radiation could increase the CAs and SCEs frequencies. This study reinforces the relevance of the biomonitoring of hospital workers chronically exposed to ionizing radiation.

Micronucleus frequency in human lymphocytes after exposure to diphenylamine in vitro.

Diphenylamine (DPA) is an antioxidant compound that occurs naturally in several vegetables. It is widely applied in agriculture for preservation of the quality of apples and pears, and used for controlling superficial scald, a disorder that renders fruits of a number of apple cultivars unfit for the market. Because of its anti-oxidative properties, DPA also has several industrial applications. The potential genotoxic effect of DPA on human lymphocytes has previously been investigated in only two studies, which focused on detection of chromosome aberrations and sister chromatid exchange, respectively. In the present analysis, we evaluated micronucleus (MN) formation in freshly isolated human peripheral lymphocytes exposed to different concentrations (0.625, 1.25, 2.50, 5.0 and 10.0µg/ml) of DPA. Peripheral venous blood was collected from ten healthy subjects, and a total of 10,000 bi-nucleated cells were analyzed. Results indicated that DPA significantly increased the micronucleus frequency at concentrations of 1.25µg/ml and higher. Significant differences in the MN frequency were also found between the lower dose (0.625µg/ml) and all other doses tested, with the exception of 1.25µg/ml. Our results indicate a potential cytogenetic effect of DPA on human cells in vitro and require further in vivo studies to clarify the actual genotoxicity of this compound and the consequent risks for human health.

Endothelial nitric oxide synthase intron 4 VNTR gene polymorphisms in European and African populations.

Endogenous nitric oxide (NO) is a molecule synthesized by endothelium nitric oxide synthase encoded by the ecNOS gene that plays an important role in regulating the systemic, cardiac and pulmonary circulation. Impairment in NO synthesis has been associated to many cardiovascular disorders, including coronary artery disease and hypertension. We investigated the frequency of the intron 4 VNTR ecNOS gene polymorphism in an Ivorian and an Italian population. The frequencies of the ecNOSb/b, ecNOSa/b and ecNOSa/a genotypes were 0.422, 0.476, and 0.102, respectively, for the Ivorian sample, and 0.712, 0.269, and 0.019, respectively, for the Italian population. The frequencies of ecNOS4b and ecNOS4a alleles were 0.660 and 0.340, respectively, for the Ivorian group, and 0.847 and 0.153, respectively, for the studied Italian population. Genotype frequencies were in Hardy-Weinberg equilibrium in both populations. The Ivorian population showed a significantly higher frequency of the ecNOS4a allele compared to other African and non-African populations, while the Italian sample confirmed the high genetic homogeneity of this polymorphism among Europeans. The maldistribution of endothelial ecNOS polymorphisms between populations could be the results of differential exposure to selection pressures in Africa and during the out-of-Africa expansion.

Chromosomal aberrations in cultured human lymphocytes treated with the fungicide, Thiram.

In vitro effects of different concentrations of Thiram were tested on human lymphocytes to determine, by means of the chromosome aberrations (CAs) assay, whether this fungicide could induce clastogenic damage. Evidences of the effect of Thiram on human lymphocytes were limited to sister chromatid exchange, micronuclei formation, and comet assays. We evaluated 0.01, 0.1, 1.2, and 12.0 µg/mL of Thiram, where 0.01 µg/mL represent the acceptable daily intake dose set by the World Health Organization and the Food and Agriculture Organization for fruit and vegetables, whereas 0.1, 1.2, and 12.0 µg/mL are its multiple values. Results indicated that human lymphocytes treated in vitro with Thiram at concentrations of 1.20 and 12.0 µg/mL significantly increased CAs frequency, compared with the negative control, whereas at lower concentrations (0.01 and 0.1 µg/mL), this effect was not observed. However, Thiram showed a clastogenic effect also at the concentration value of 1.2 µg/mL that represents a lower value with respect to the residue limits found in Italy for grapes, strawberries, potatoes, tobacco, and other fruits and vegetables. Finally, according to some evidence obtained from the study of other fungicides, Thiram produced a significant reduction in the mitotic index with increasing concentration.

Insertional variability of four transposable elements and population structure of the midge Chironomus riparius (Diptera).

The dipteran Chironomus riparius is found across the entire Palearctic region; its larvae are among the most abundant macroinvertebrates inhabiting inland waterbodies. Chironomid larvae have been extensively used in ecotoxicological and cytogenetic research, but relatively little is known on the population structure of this species. Transposable elements (TEs) are DNA sequences that are capable of autonomous replication; the number and genomic location of TE insertions varies across individuals; this variability is increasingly being used in population studies. Several TEs had been characterized in Chironomids; this enabled the analysis of insertional variability of four different TEs in six natural populations of C. riparius from Italy, Bulgaria and Russia using a PCR-based method, transposon insertion display (TID). The method allows to obtain dominant markers, similar to AFLP. In all populations, TE insertions showed high individual polymorphism, while median copy numbers of the same TEs did not vary between populations. Analysis of molecular variance (AMOVA) detected significant differentiation between populations for three of the TEs; although no correlation between genetic and geographic distances was found, the corresponding population structures were found to be significantly correlated and indicate a degree of isolation by distance. TEs belonging to different classes have different mechanisms of replication, resulting in different transposition rates of mobilization; the finding of mostly concordant population structuring for three of the TEs indicates that population dynamics contributed significantly in shaping the detected insertional polymorphism.

Combined analysis of chromosomal aberrations and glutathione S-transferase M1 and T1 polymorphisms in pathologists occupationally exposed to formaldehyde.

The formaldehyde (FA) genotoxic potential in occupationally exposed individuals is conflicting. A relevant indoor-air FA pollution was found in hospitals and scientific institutions where FA is used as a bactericide and tissue preservative. In the present study, we evaluated the frequency of chromosomal aberrations (CAs) in peripheral blood lymphocytes from workers in pathology wards who have been exposed to FA, compared with a group of unexposed subjects. The subjects were also analyzed for the GSTM1 and GSTT1 metabolic gene polymorphisms. The exposed subjects showed a significant increase in the frequency of CA per cell and in the percentage of cells with aberrations compared to control subjects. The different GST genotypes did not affect the level of cytogenetic damage since CA frequencies were not statistically different between the GST "null" genotypes and the GST "positives". The generalized linear models showed that the number of CAs and cells with CAs increased with age, but, independent of age, it was significantly higher in the experimental rather than in the control group. Cubic-spline regression confirmed the linear relationship between CAs and age, but it provided evidence for a non-linear relationship between CAs and the number of years of FA exposure. Similar results were observed when the model included the number of cells with CAs as dependent variables. Our results demonstrate that air FA induces CAs even consequently to low levels of daily exposure, indicating an increased risk of genetic damage for workers exposed to this air pollutant.

In vitro aneugenic effects of the fungicide thiabendazole evaluated in human lymphocytes by the micronucleus assay.

Thiabendazole is a benzimidazole-derived compound widely employed in agriculture as anthelmintic and fungicide. It is also used as a post-harvest fungicide for imported citrus fruits during transport and storage, and thus, it was found at high concentration in fruits and vegetables. Several studies have analyzed the potential genotoxic effect of thiabendazole on different prokaryotic and eukaryotic systems, but in many cases, results were contradictory. In the present study, the genotoxic potential of thiabendazole have been evaluated, by micronucleus assay in freshly isolated human peripheral lymphocytes. The cells were incubated with 0.5, 5 and 50 µg/ml concentrations of the tested substance for 48 h at 37°C. Mitomycin C at final concentration of 0.01 µg/ml culture was used as a positive control. The results indicated that the thiabendazole significantly (P < 0.05) increased the micronucleus frequency compared with the negative control in all treatment concentrations, indicating a potential aneugenic hazard of thiabendazole in cultured human peripheral lymphocytes. The cytokinesis-block proliferation index value, however, was not decreased significantly compared with the negative control. Significant (P < 0.05) differences in the micronuclei frequency were also found between the lower dose (0.5 µg/ml) and the other two analyzed doses of thiabendazole. In contrast, no differences were found between 5 and 50 µg/ml of thiabendazole and between DMSO and negative control. Finally, control cultures treated with the known mutagen MMC showed a very consistent increase in MN with respect to the negative controls.