Acute changes in sputum collected from exposed human subjects in mining conditions.

Neprilysin (NEP) is a key cell surface peptidase in the maintenance of airway homeostasis and the development of pulmonary disorders. However, little information is available about the effect of particulate matter (PM) on airway NEP. In this controlled human exposure study, changes in induced sputum were measured in 11 subjects at baseline, overshot (OS) mucking, and diesel exhaust (DE) exposure days. Neither OS condition nor DE exposure was found to induce significant changes in total protein, but DE induced significant increases in cell numbers of macrophages and epithelium. Moreover, significant increases in soluble NEP were observed following OS mining dust particulates (0.43 +/- 0.06 nmol/microg protein/min; p = .023) and DE exposure (0.40 +/- 0.03 nmol/microg protein/min; p = .035) when compared with the baseline control (0.30 +/- 0.04 nmol/microg protein/min), with 42% and 31% average net increase, respectively. Pearson's correlation analyses indicated that sputum NEP activity was significantly associated with personal exposure product (elemental carbon concentration [mg/m(3)] x time [min]; C x T). The data suggest that changes in NEP activity may be an early, accurate endpoint for airway epithelial injury and provide a new insight into the mechanism of airway effects following particulate exposure.

Acute changes in sputum IL-10 following underground exposure to diesel exhaust.

INTRODUCTION: Although exposure to diesel exhaust has been linked with adverse health effects, little is known about the acute effects of exposure in the underground workplace. METHODS: Cross-shift spirometry and sputum induction were completed on twelve subjects associated with comminuted rock removal (mucking) operations in an underground copper mine using diesel powered and pneumatic equipment on separate days, and sputum collected on a baseline non-exposure day as well. RESULTS: For diesel operations, elemental carbon exposure averaged 538 +/- 512 microg/m(3) during the 1-2 hour operations. Sputum interleukin-10 decreased with diesel exhaust using one ELISA assay (3.69 v. 2.32 pg/ml, p = 0.015), but increased when measured with a different ELISA kit (0.18 v. 0.59 pg/ml, p = 0.019), consistent with an overall decline in IL-10 protein concentration but an increase in the biologically active form. Sputum interleukin-6 decreased with exposure to diesel exhaust, although this change lost statistical significance when restricted to non-smokers. There were no significant changes in spirometry, interleukins 1beta, 4, and 8, tumor necrosis factor alpha or 8-hydroxy-2'-deoxyguanosine. CONCLUSION: High levels of diesel exhaust can result in rapid changes in sputum IL-10, suggesting possible protein modification.

Identifying antecedent conditions responsible for the high rate of mining injuries in Zambia.

The incident rates of mining-related accidents and injuries in developing countries exceed those of developed nations. Interventions by international organizations routinely fail to produce appreciable long-term improvement. One major reason is the inability to identify and analyze the underlying factors responsible for creating unsafe working conditions. Understanding these antecedent conditions is necessary to formulate effective intervention strategies and prioritize the use of limited resources. This study utilized a logic model approach to determine the root causes and broad categories of potential interventions for mining accidents and injuries in Zambia. Results showed that policy interventions have the greatest potential for substantive change. A process of educating officials from government and mining companies about the economic and social merits of health and safety programs and extensive changes in regulatory structure and enforcement are needed.

Silicosis and tuberculosis in Zambian miners.

Silicosis and tuberculosis (TB) are significant mining-related illnesses in developing countries. The purpose of this study was to examine annual cases of these diseases in Zambian miners, including comparison of periods before (1960-1970) and after (1992-2002) the arrival of the HIV/AIDS pandemic. The Occupational Health and Safety Research Bureau of Zambia reported 2114 cases from 1945 to 2002. Of these, 22.7% were silicosis, 65.4% TB, and the remaining 11.9% silicotuberculosis. While silicosis cases decreased from 28.6% to 12.4% with the arrival of HIV/AIDS, there was a large increase in tuberculosis cases (37.1% to 86.1%), with a corresponding decrease in silicotuberculosis cases (34.3% to 1.6%). Although silicosis remains an occupational health issue in Zambian miners, the most significant problem appears to be the marked increase in cases of TB.