The aim of the present study was to investigate the correlation between tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-12p40-containing cytokines, in silicosis patients and healthy donors exposed to silica dust, in an attempt to clarify the reason for variety of clinical outcomes between humans with similar exposure history. Serum levels of TNF-alpha, IL-12p40, IL-12p70 and IL-23 in total group of 62 silicosis patients, 24 healthy donors with similar exposure history like patients and 19 healthy donors without exposure were determined by enzyme-linked-immunosorbent assay (ELISA) method. The serum level of TNF-alpha was significantly higher in healthy donors exposed to SiO(2) (22.4 +/- 11.1 pg/mL) in comparison with non-exposed healthy donors (14.8 +/- 8.8 pg/mL; p = 0.022) and similar to that in silicosis patients. In total, group of silicosis patients significantly elevated levels of TNF-alpha (20.9 +/- 12.9 vs. 14.8 +/- 8.8 pg/mL; p = 0.047) and IL-12p40 (94.5 +/- 51.6 pg/mL vs. 68.7 +/- 26.2 pg/mL; p = 0.029) compared to non-exposed healthy donors were observed. In addition, a strong positive correlation between TNF-alpha and IL-23 levels (r = 0.678; p = 0.022) and between TNF-alpha and IL-12p70 levels (r = 0.75; p = 0.0003) was detected in the group of exposed healthy donors, while in the group of silicosis patients, a significant positive correlation was observed only between TNF-alpha and IL-12p40 (r = 0.434; p = 0.00048), in contrast to other IL-12p40 containing cytokines. In conclusion, we could assume that the elevated serum levels of TNF-alpha are associated with exposition to silica particles, while the elevation of both TNF-alpha and IL-12p40 is associated with silicosis development and severity. Additionally, the balance between IL-12p40-containing cytokines may also contribute to the silicosis progression.

AbstractThe study was conducted among 92 male workers, divided into two groups depending on workplace and level of inorganic dust containing free crystalline SiO2 in the work environment, and 43 healthy workers without exposure to dust aerosols. The measured inhalable and respirable dust concentrations, as well as the concentration of free crystalline silica (FCS) in the respirable fraction were different for the two groups, but the percentage of free crystalline silica in the respirable fraction was almost identical. Significantly higher neopterin levels were found in workers exposed to dust, compared to the control group: 12.72 nmol/L and 6.32 nmol/L respectively (p<0.05). No significant difference was found between serum neopterin levels in both groups of the exposed workers. Among the groups with different length of service, a statistically higher neopterin level was evident only in the workers with length of service less than 10 years (p<0.05). The correlation analysis did not find a significant dependence of neopterin levels on the age of the studied workers or on the duration of smoking in packet years. The difference between neopterin levels in smokers and non-smokers was nonsignificant. The results obtained show that increased neopterin levels in the exposed workers are not influenced by individual features, duration and level of exposure to inorganic dust, but mostly by the presence of FCS in the respirable fraction.

AbstractPure tone audiometry screening and ear examinations were conducted among 138 males working as machine and equipment operators occupationally exposed to intermittent noise of 85 to 105 dBA. Hearing loss up to 30 dB (preserved socially adequate hearing) was found in 25 workers. The hearing impairment was confirmed by distortion products of otoacoustic emissions measurements. A sharp increase in the frequency of cases can be found among the workers with service length over 10 years. While the frequency of the cases among workers with service length below 10 years is 5.45%, it is 26.5% among the subjects with service length over 10 years, with a gradual increase as a result of the increase in exposure duration. A positive correlation (p < 0.05) was found between the frequency of hearing impairment among the workers and the years of exposure to excessive noise levels. Some measures for preventing occupational noise-induced hearing loss were suggested.

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