Objective-To investigate if blood Cu++/Zn++ superoxide dismutase, glutathione peroxidase, catalase, and total plasma antioxidant activities could be markers of biological activity resulting from exposure to respirable coal mine dust in active miners, and of pneumoconiosis in retired miners. Methods-Blood samples were randomly obtained from active surface workers (n = 30) and underground miners (n = 34), and from retired miners without (n = 21), and with (n = 33) pneumoconiosis. Antioxidant enzyme activities and total plasma antioxidants were measured in erythrocytes and plasma. Non-parametric tests were completed by analyses of covariance to compare antioxidants between groups, taking into account potential confounding factors (age, smoking history (pack-years)).Results-Erythrocyte Cu++IZn++ superoxide dismutase activity was significantly higher in the group of underground miners than the group of surface workers. The differences in total plasma antioxidants and plasma glutathione peroxidase activity between both groups were related to age. Glutathione peroxidase activity increased in the plasma of retired miners with pneumoconiosis, compared with retired miners without pneumoconiosis. No differences were found either in erythrocyte antioxidant enzyme activities or in total plasma antioxidants between the groups of retired miners without and with pneumoconiosis. Conclusions-In this study, erythrocyte Cu++/Zn++ superoxide dismutase activity may be considered as a marker of effect of respirable coal mine dust in exposed workers. This result is in agreement with the hypothesis that reactive oxygen species are involved in cell injury induced by coal mine dust, and may be predictive of the degree ofinflammation and pneumoconiosis induced by coal mine dust. The increase in glutathione peroxidase activity in the plasma of retired miners with pneumoconiosis may be the result of a response to the increasing hydrogen peroxide (HO,) production due to the disease process.(Occup Environ Med 1996;53:41-45)

Objectives-To better understand the relations between occupational exposure, blood antioxidant enzyme activities, total plasma antioxidant concentration, and the severity of coal workers' pneumoconiosis (CWP). Methods-Blood samples were obtained from miners without CWP exposed to low dust concentrations for >4 years at the time of the study (n = 105), or exposed to high dust concentrations for >14 years at the time of the study (n=58), and from retired miners with CWP (n=19). Miners without CWP were classified into three subgroups according to their estimated cumulative exposure to dust. Chest x ray films were obtained for each miner. Miners were classified in five subgroups according to their International Labour Organisation (ILO) profusion grades. Univariate tests were completed by multiple linear regression analyses. Results-The estimated cumulative exposure to dust was strongly positively related to erythrocyte catalase activity and strongly negatively related to Cu ++ /Zn ++ SOD activity only in miners exposed to high dust concentrations for >14 years at the time of the study (F tests p=0.006 and p=0.004 respectively). Moreover, catalase activity was strongly related to the severity of CWP expressed as five subgroups of ILO profusion grades (F test p=0.003); the greatest diVerence in the mean values was found between the group of 1/1 to 1/2 ILO profusion grades and the group of 2/1 to 3/3 ILO profusion grades. Conclusion-These results are in good agreement with the hypothesis that production of reactive oxygen species may be an important event in the exposure to coal mine dusts and the severity of CWP. Erythrocyte catalase and Cu ++ /Zn ++ SOD activities are more closely related to recent exposure to high dust concentrations than to cumulative exposure, and could be considered as biological markers of exposure rather than as markers of early adverse biological eVect. (Occup Environ Med 1998;55:533-540)

For this article we investigated the role of three blood antioxidant enzyme activities and total antioxidant status (TAS) as biological markers of oxidative stress in workers exposed to mercury (Hg(o)) vapors. Twenty-two female workers took part in the study. The examination included a questionnaire on age, educational level, occupational history, actual health status, previous accidents and diseases, smoking and dietary habits, and alcohol consumption. Blood and urine sampling for biological analyses completed this examination. The workers were classified into three subgroups according to their creatinine-corrected Hg concentration in urine. Blood antioxidant enzyme activities and TAS were compared between groups with nonparametric distribution-free methods. A significant difference existed in catalase activity and a slight, but not significant, difference existed in Cu2+/Zn2+ superoxide dismutase (Cu2+/Zn2+ SOD) activity between the three groups. No differences were observed in either the glutathione peroxidase activity or the TAS between these groups. Catalase and Cu2+/Zn2+ SOD activities were increased in the groups of workers with higher creatinine-corrected urinary Hg concentrations when compared with the group of lower creatinine-corrected urinary Hg concentrations. Catalase activity was positively correlated with the creatinine-corrected concentration of Hg in urine, and Cu2+/Zn2+ SOD activity was slightly correlated with the creatinine-corrected concentration of Hg in urine. The role of erythrocyte catalase and Cu2+/Zn2+ SOD activities we have measured is in agreement with the hypothesis of the involvement of reactive oxygen species production as an important event in chronic exposure to Hg(o) vapors in humans. In spite of the small size of the sample, these results indicate that erythrocyte catalase and Cu2+/Zn2+ SOD activities could be considered as markers of biological effect in workers exposed to Hg(o) vapors.

This study investigated whether differences in the prevalence and severity of coal workers' pneumoconiosis (CWP) between three coal mines could be related to differences in oxidative stress exposure as evaluated in vivo through red-blood-cell antioxidant enzyme activities. Blood samples were obtained from 229 miners selected according to their occupation and their pneumoconiotic status. The following biomarkers were evaluated: erythrocyte catalase, Cu2+/Zn2+ superoxide dismutase (Cu2+/Zn2+ SOD), and glutathione peroxidase activities. Antioxidant enzyme activities did not differ significantly between the group of surface workers in Lorraine and the group of underground miners without CWP in Lorraine and in the other coal mines. Erythrocyte Cu2+/Zn2+ SOD activity was slightly decreased in the group of active underground miners with simple pneumoconiosis as compared with the group of miners without CWP in Nord/Pas-de-Calais. No effect was seen between retired miners at different stages of CWP. Our findings indicate that differences in the prevalence and severity of CWP do not seem to be related to various oxidative activities of coal dust particles, at least as reflected by measurements of antioxidant enzyme activities in circulating erythrocytes in this study.

Background We investigated if blood Cu++/Zn++ superoxide dismutase, glutathione peroxidase, and catalase activities are increased and total plasma antioxidant concentration is decreased in coke oven workers exposed to polycyclic aromatic hydrocarbons. Methods Ninety‐six coke oven workers participated in the study. Nonexposed workers (n = 105) were randomly sampled among power plant workers in the same age range. The examination included a questionnaire on health status, occupational history, smoking, and dietary habits. Blood samples completed the examination. Coke oven workers were classified into low‐, middle‐, and high‐exposure groups based on the benzo[a]pyrene (B[a]P) air concentrations and were further classified into the categories “topside” and “non‐topside,” according to their proximity to the ovens. Results Erythrocyte glutathione peroxidase activity increased with age (r = 0.18, P = 0.061) in power plant workers, whereas plasma glutathione peroxidase activity decreased with age (r = −0.18, P = 0.068) and erythrocyte glutathione peroxidase activity was inversely correlated with the number of cigarettes per day (r = −0.28, P = 0.08) in coke oven workers. Comparison of blood antioxidant enzyme activities and total plasma antioxidant concentration between coke oven and power plant workers showed that erythrocyte glutathione peroxidase activity was significantly lower in coke oven workers, even after adjustment for potential confounding factors. No differences were found either in other blood antioxidant enzyme activities or in total plasma antioxidant concentration between coke oven and power plant workers. Moreover, no trends toward decreased glutathione peroxidase activity among the three subgroups of B[a]P exposure were observed, and no differences either in blood antioxidant enzyme activities or in total plasma antioxidant concentration between the two groups of job categories were found. Conclusions Production of reactive oxygen species seems not to be increased in coke oven workers. Am. J. Ind. Med. 34:272–279, 1998. © 1998 Wiley‐Liss, Inc.