IMMUNOGLOBULIN LEVELS IN WORKERS EXPOSED TO INORGANIC MERCURY

The serum immunoglobulin (IgG, IgM and IgA) concentrations of 44 mercury-exposed workers were examined and compared with those of non-exposed, age- and sex-matched individuals. At the time of testing, the exposed population had a mean (+/- S.D.) mercury urinary concentration of 24.7 +/- 19.1 and in 40 of them urinary mercury levels were below the currently accepted limit of 50 mu g/g creatinine. Increased IgG, IgA and IgM levels were found in the mercury-exposed individuals and in 16, a second evaluation was performed six months later. During the intervening six months, the level of hygiene was improved throughout the plant, and urinary mercury concentrations were determined monthly in each worker. Despite a significant reduction in mercury urinary concentrations, serum immunoglobulin levels did not return to the normal range. There was no correlation between the length or level of exposure and the immunoglobulin levels. Liver protein synthesis, as studied by factor V, prothrombin time, prealbumin and transaminase activity, was normal and liver injury, as evaluated by serum aspartate and alanine aminotransferase activities (AST and ALT, respectively), was not observed. No haemotological abnormalities were noted. These results indicate that ''safe'' levels of mercury exposure may lead to humoral immunological stimulation.742727

Non-malignant asbestos-related diseases in Brazilian asbestos-cement workers

Background Production of asbestos-cement products in Brazil started in the 1940s, peaked in the 60-70s and is still an active industry. This study was designed to assess the non-malignant effects of asbestos exposure in the asbestos-cement industry in Brazil. Methods A group of 828 former asbestos-cement workers enrolled in a cross-sectional and cohort study of respiratory morbidity, submitted to a detailed occupational history, respiratory symptoms questionnaire, spirometry, PA chest x-ray, and high resolution computed chest tomography (HRCT). Asbestos exposure was assessed by years of exposure, cumulative exposure (a semi-quantitative method), and latency time from first exposure. Asbestosis and pleural thickening were assessed according to HRCT criteria. Results Asbestosis was present in 74 (8.9%) and pleural thickening in 246 (29.7%). Using the HRCT as the "best available evidence", it was shown that were more false negatives than false positives in the x-ray readings for parenchymal (21.6% false negatives, 4.2% false positives) and pleural (26.0% false negatives, 14.4% false positives) diseases due to asbestos. Latency time from first exposure was the best predictor for both asbestosis and pleural thickening. Subjects in the higher exposure groups presented lower levels of lung function. Obstructive defects were significantly related to smoking, shortness of breath, body mass index, and age, whereas restrictive defects were related to asbestosis, shortness of breath, and latency time. Chronic bronchitis increased with latency time in the three smoking groups and was significantly related to pleural thickening (OR 1.56 (1.00-2.42)). Shortness of breath was significantly associated with body mass index and pleural thickening (OR 1.30 (1.24-2.09)). Conclusions Pleural thickening and asbestosis showed a significant association with latency time and exposure. FVC and FEV1 decreased across increasing profusion with an added effect of pleural thickening. There was a significant and independent effect of exposure on lower levels of FVC and FEVl. Obstructive defects were mainly related to smoking and restriction to asbestosis. Dust exposure and smoking were synergistic in increasing chronic bronchitis and shortness of breath report. Shortness of breath report was also related to pleural thickening and higher body mass index. (C) 2001 Wiley-Liss, Inc.40324025