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The purpose of this study is the evaluation of possible toxicological effects on dental personnel, who are exposed to the production materials of prostheses during their entire working life. In this study, the level of methyl methacrylate (MMA) in ambient air was measured as an indicator of external exposure on the personnel. In order to evaluate the possible toxic effects of oxidative stress, which is thought to play an important role in the formation process of many diseases such as cancer, blood samples of volunteers were examined via the ultraviolet-spectroscopic determination of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase antioxidant enzyme activities, comparing occupationally MMA-exposed ( n = 69) and control ( n = 67) groups. In these groups, malondialdehyde (MDA) and glutathione levels were also determined by the same method. The results showed that SOD activity and MDA and glutathione levels were significantly higher in the exposed group when compared with the control group ( p < 0.001). A significant decrease was determined in the glutathione peroxidase activities of the exposed group ( p < 0.05). No significant difference in CAT activities between the groups has been found. When the results obtained in the study are considered, it is suggested that an adaptive response might be developed by dental technicians against low-level MMA exposure.

Purpose: Occupational exposure to low levels of ionizing radiation (IR) in radiology department staff may affect their antioxidant status. The aim of this study was to evaluate the oxidative stress parameters in radiology staff that are occupationally exposed to IR in a hospital setting., Materials and Methods: The study population included 40 exposed radiology staff and 30 control subjects. The radiation doses of exposed staff ranged between 0.10 and 3.8 milligray (mGy) per month. The subjects' antioxidant status was determined by measuring the activities of copper zinc-superoxide dismutase (CuZn-SOD), selenium dependent glutathione peroxidase (Se-GPx), catalase (CAT) enzymes, and the levels of malondialdehyde (MDA) in erythrocytes., Results: Our results showed that the activities of erythrocyte CuZn-SOD and Se-GPx enzymes observed for the radiation exposed group were significantly higher than in the controls. The activity of CAT enzyme and MDA levels were significantly lower in the exposed group than in the controls. Moreover, we investigated the influence of confounding factors on antioxidant enzymes or lipid peroxidation (LP), but we could not find any associations between them., Conclusions: Our study indicates the presence of stimulant effect of chronic low-dose radiation in exposed individuals, resulting in enhanced resistance to oxidative stress.

Purpose: Jet fuel is a common occupational exposure risk among military and civilian populations. The purpose of this study was to evaluate genotoxic and oxidative effects in workers occupational exposure to jet propulsion fuel (JP-8)., Methods: In this study, sister-chromatid exchange (SCE), high frequency of SCE cells (HFCs), and micronuclei (MN) were determined for 43 workers exposed to JP-8 and 38 control subjects. We measured the antioxidant enzyme activities including that of superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT). The levels of thiobarbituric acid-reactive substances (TBARS) were also studied. Urinary 1- and 2-naphthol excretion was used as a biomarker of occupational exposure to JP-8., Results: The results obtained from cytogenetic analysis show a statistically significant increase in frequency of SCE in the exposed workers when compared to controls (P < 0.05). Interestingly, the mean value of the frequency (%o) of MN and HFCs for workers and controls did not show any statistical differences (P > 0.05). Oxidative stress parameters were not statistically different between exposed and control groups except for TBARS levels., Conclusion: Urinary 1-and 2-naphthol levels of exposed workers were found to be significantly higher than those of control subjects. Occupational exposure to JP-8 resulted in no significant genotoxic and oxidative effects, while smoking is the principal confounding factor for the some parameters. To understand the genotoxic and oxidative effects of JP-8 exposure, further studies should be planned to find out whether human populations may be at increased risk for cancer because of the exposures related to occupation and lifestyle.

Ionizing radiation is known to induce mutations and cell transformations, predominantly by causing single-strand and double-strand DNA breakage, thereby leading to chromosome instability and carcinogenesis. The aim of this study was to evaluate genotoxic effects in hospital staff exposed to low-dose ionizing radiation in comparison with a selected control group, by using the cytokinesis-blocked micronucleus (CBMN) and sister chromatid exchange (SCE) tests in peripheral blood lymphocytes. The study included 40 exposed radiology staff and 30 control subjects. The frequency of micronuclei (MN) was significantly increased in radiation-exposed groups compared with control persons (p < 0.05). The frequency of SCE did not show any significant difference in the exposed individuals in comparison to the controls. Our results showed that low-level chronic occupational exposure to ionizing radiation causes an increase of MN frequency in chromosomes, even though the absorbed doses were below the permissible limits. Our studies indicate that the CBMN assay is considered to be sensitive test in contrast to SCE analysis to evaluate chromosomal damage induced by ionizing radiation.

This study was designed to evaluate the possible in vivo induction of DNA damage by exposure to radiation in cardiologists. The alkaline comet assay (single cell gel electrophoresis, SCGE), which appears to be a promising tool with which to estimate DNA damage at the single cell level, has been used. The assay was carried out on 30 cardiologists currently employed in a busy cardiac service and 30 healthy unexposed controls. Venous blood samples were obtained from the exposed and control subjects and SCGE was examined in 100 cells graded as undamaged, intermediate, and tailed nuclei. The number of undamaged nuclei was almost the same in control and exposed subjects. The extent of DNA migration (SCGE assay) did not distinguish between the samples in either the nonsmoker exposed or nonsmoker control subjects, which leads one to wonder whether a difference in DNA damage really exists. Previous studies reported increased DNA damage in blood lymphocytes of smokers. In our study, the percentage of damaged cells increased either with the frequency of smoking or exposure to radiation. A statistically significant difference was observed both in smokers and exposed subjects. In conclusion, the elevated grade of DNA damage in cardiologists exposed to radiation indicates a possible genotoxic hazard, therefore, careful measures and full cooperation between cardiologists and radiologists should be undertaken to reduce the exposure to radiation.

People employed in the shoe manufacture and repair industry are at an increased risk for cancer, the strongest evidence being for nasal cancer and leukaemia. A possible causal role for formaldehyde is likely for cancer of the buccal cavity and nasopharynx. Exfoliated buccal cells are good source of tissue for monitoring human exposure to inhaled and ingested occupational and environmental genotoxicants. To assess the cytogenetic damage related to occupational exposure to airborne chemicals during shoe-making and the processes in pathology and anatomy laboratories, the micronuclei (MN) count per 3000 cells was measured in buccal smears from shoe-workers (group I, n = 22) exposed to mainly n-hexane, toluene and methyl ethyl ketone (MEK) and from anatomy and pathology staff (group II, n = 28) exposed to formaldehyde (FA). Eighteen male university staff were used as controls. The mean time-weighted average (TWA) concentrations of n-hexane, toluene and MEK in 10 small shoe workshops were 58.07 p.p.m., 26.62 p.p.m. and 11.39 p.p.m., respectively. The measured air concentrations of FA in the breathing zone of the anatomy and pathology laboratory workers were between 2 and 4 p.p.m. Levels of 2,5-hexadione (2,5-HD) and hippuric acid (HA), metabolic markers of n-hexane and toluene exposure, respectively, were significantly higher in the urine of workers in group I than in control subjects (p < 0.001 and p < 0.01, respectively). The mean (+/- SD) MN (0/00) [corrected] frequencies in buccal mucosa cells from workers in group I, group II and controls were 0.62 +/- 0.45%, 0.71 +/- 0.56% and 0.33 +/- 0.30%, respectively (p < 0.05 and p < 0.05 compared with controls for group I and group II, respectively). The effects of smoking, age and duration of exposure on the frequency of micronucleated buccal cells from workers in all three groups studied were also evaluated. Overall, the results suggest that occupational exposure to organic solvents, mainly n-hexane, toluene, MEK and FA, may cause cytogenetic damage in buccal cells and that use of exfoliated buccal cells seems to be appropriate to measure exposure to organic solvents.

Formaldehyde (FA) is a widely used industrial chemical. Sufficient evidence exists to consider FA as an animal carcinogen. A possible causal role for FA may be considered likely for cancer of the nasopharynx and the nasal cavities in humans. The frequency of micronuclei (MN) in cells of the nasal mucosa was evaluated for 23 individuals in pathology and anatomy laboratories exposed to FA. Twenty-five healthy subjects were selected from the university and hospital staff as a control group. The measured air concentrations of FA in the breathing zone of the laboratory workers were between 2 and 4 ppm. The mean +/- SD values of nasal mucosa MN (per 1000) frequency from exposed and controls were 1.01 +/- 0.62 and 0.61 +/- 0.27, respectively (p < 0.01). Effect of smoking, age, sex and duration of exposure on the genotoxicity parameters analyzed were also evaluated. Our data suggest that low level exposure to FA is associated with cytogenetic changes in epithelial cells of the nasal region and that nasal mucosa cells exposed through respiration is an important target of FA-induced genotoxic effects.

1. To evaluate the effects of occupational long-term co-exposure to n-hexane, toluen, and methyl ethyl ketone (MEK) on NK cell activity and serum IL-2, gamma-IFN levels, we studied a group of workers employed in a shoe factory where the jobs include use of glues and adhesives containing mainly n-hexane, and at low concentrations, toluen and MEK. 2. No differences were found in these parameters even in those workers with 3.3-fold higher mean levels of urine, 2,5-Hxdn and approximately twofold higher mean levels of urine hippuric acid as compared to controls. 3. We conclude that chronic co-exposure to n-hexane, toluen, and MEK at these levels is not associated with an impairment on either NK cell activity or serum IL-2 and gamma-IFN levels.

To investigate the effects of polycyclic aromatic hydrocarbons (PAHs) on the human immune system, analyses were performed on T-cell subsets (CD4+, CD8+), B-cells (CD19+), serum immunoglobulin levels (IgG, IgM, IgA) and white blood cell percentages of 16 male workers who were employed in road paving operations and compared to 12 unexposed male controls. PAH exposure was assessed using urinary 1-hydroxy-pyrene (1-OHP) levels and was found to be significantly higher in workers than in the controls. While the CD4+ cell percentage and the CD4+/CD8+ ratio were significantly higher in the PAH-exposed group, the percentages of CD8+ and CD19+ cells were unchanged. There was also a significant enhancement in serum IgG levels and the percentage of monocytes in the workers compared to the control group. These data suggest that chronic exposure to PAHs may affect some immune functions in humans.

Bitumen samples and fumes consist essentially of polycyclic hydrocarbons (PAH) and their derivatives, some of which are known to be carcinogenic or co-carcinogenic in animals. The level of total PAH is low when compared with coal-tar products. There is very limited data on possible health risk from exposure to bitumen fumes in workers. In this study, sister-chromatid exchange (SCE), micronuclei (MN) and high frequency of SCE cells (HFCs) were determined for 28 workers exposed to bitumen fumes and 28 control subjects. Urinary 1-hydroxypyrene (1-OHP) excretion was used as a biomarker of occupational exposure to PAH. The mean value of 1-OHP excretion of workers was 0.78+/-0.46 micromol/mol creatinine and for controls 0.52+/-0.44 micromol/mol creatinine (p<0.05). The mean values of SCE per cell and the frequency ( per thousand) of MN in peripheral lymphocytes from the workers and controls were 5.13+/-0. 64, 4.71+/-0.67, and 2.25+/-0.42, 1.79+/-0.32 respectively (p<0.05, p<0.0001). The mean value of HFCs for workers and controls were 7. 85+/-2.3 and 7.05+/-3.16, respectively (p>0.05). Our data reveal that bitumen fumes during road paving operations are absorbed by workers and that bitumen fume exposure is able to significantly induce cytogenetic damage in peripheral lymphocytes of workers after controlling some possible confounding factors, such as age, sex and smoking habits., (Copyright 1998 Elsevier Science B.V.)