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.

Reduction in urinary arsenic with bottled-water intervention.

The study was conducted to measure the effectiveness of providing bottled water in reducing arsenic exposure. Urine, tap-water and toenail samples were collected from non-smoking adults residing in Ajo (n=40) and Tucson (n=33), Arizona, USA. The Ajo subjects were provided bottled water for 12 months prior to re-sampling. The mean total arsenic (microg/L) in tap-water was 20.3+/-3.7 in Ajo and 4.0+/-2.3 in Tucson. Baseline urinary total inorganic arsenic (microg/L) was significantly higher among the Ajo subjects (n=40, 29.1+/-20.4) than among the Tucson subjects (n=32, 11.0+/-12.0, p<0.001), as was creatinine-adjusted urinary total inorganic arsenic (microg/g) (35.5+/-25.2 vs 13.2+/-9.3, p<0.001). Baseline concentrations of arsenic (microg/g) in toenails were also higher among the Ajo subjects (0.51+/-0.72) than among the Tucson subjects (0.17+/-0.21) (p<0.001). After the intervention, the mean urinary total inorganic arsenic in Ajo (n=36) dropped by 21%, from 29.4+/-21.1 to 23.2+/-23.2 (p=0.026). The creatinine-adjusted urinary total inorganic arsenic and toenail arsenic levels did not differ significantly with the intervention. Provision of arsenic-free bottled water resulted in a modest reduction in urinary total inorganic arsenic.

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.

House dust and inorganic urinary arsenic in two Arizona mining towns.

Residents of copper mining and smelting towns may have increased risk of arsenic exposure from elevated arsenic contained in environmental media. To determine the relation of arsenic in house dust to inorganic urinary arsenic concentrations, a door-to-door survey was conducted in Hayden and Winkelman, Arizona. A total of 122 households (404 individuals) participated; 85 provided dust samples. Urine was collected at first morning void and analyzed for total and speciated arsenic. Speciation of arsenic was performed in samples with total arsenic above 10 micro g/l (N=106). The generalized estimating equation was used to determine the relation between urinary and house dust arsenic concentrations, allowing adjustment for the correlation of measurements obtained from the same home. Seafood consumption during the past 3 days and smoking contributed significantly to inorganic urinary arsenic, after adjusting for age and gender. Arsenic in house dust was not significantly associated with inorganic urinary arsenic measurements in this population.

Medical surveillance of clandestine drug laboratory investigators.

Law enforcement officers investigating clandestine drug laboratories may be exposed to a wide range of hazardous chemicals. This study was conducted to determine the extent of persistent health effects seen in California drug laboratory investigators after occupational exposure. Study participants with a minimum of 1 year of laboratory investigations completed a questionnaire evaluating occupational and personal health history and consented to review of their medical surveillance examinations and administrative records. The 40 participating investigators averaged 6.1 +/- 2.5 annual medical evaluations for the period 1991 to 1998. Average annual decline in forced expiratory volume in 1 second (FEV1) was 64.0 +/- 138.0 mL/year (median, 40.0 mL/year). For 34 subjects with valid exposure data, longer duration use of respiratory protection was associated with a less rapid decline in FEV1, whereas lack of respiratory protection during the processing phase of laboratory investigation was associated with a more rapid annual decline. There were no significant longitudinal changes in serum alanine aminotransferase, serum aspartate aminotransferase, hemoglobin, and white blood cell count, although platelets declined slightly. Law enforcement personnel investigating clandestine drug laboratories may have long-term respiratory effects from chemical exposure, for which more assiduous use of respiratory protection is recommended.

Longitudinal decline in lung function: evaluation of interleukin-10 genetic polymorphisms in firefighters.

During annual medical monitoring, some firefighters are found to have rates of decline in forced expiratory volume in one second (FEV1) far exceeding their peers. Interleukin-10 (IL-10) suppresses inflammation, and single nucleotide polymorphisms (SNPs) in the IL-10 gene may confer variable susceptibility to more rapid decline in lung function. In 1204 firefighters with at least six annual FEV1 measurements, increased age and greater initial FEV1 were associated with more rapid decline in lung function. DNA collected from 379 of these firefighters was screened for IL-10 SNPs at -1117, -854, 919, 1668, and 1812. A statistically significant difference in decline in lung function was found based on genotyping at the 1668 SNP. Evaluation of gene polymorphisms regulating lung inflammation may help to explain some of the variation in rate of decline in lung function in firefighters.

Rapid decline in sputum IL-10 concentration following occupational smoke exposure.

The acute effects of smoke exposure on inflammatory mediators such as interleukin-10 (IL-10), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha) are not well understood. Our study was designed to measure sputum concentrations of these cytokines in firefighters following low-level smoke exposure. At baseline, participating firefighters underwent blood collection, pulmonary function testing, and sputum induction through inhalation of nebulized hypertonic saline. Study participants later performed overhaul of a structural fire, during which time they wore cartridge respirators and were monitored for smoke exposure. Overhaul involves searching for and extinguishing hidden sources of combustion. One hour following overhaul, blood, pulmonary function data, and induced sputum were again collected. IL-10, IL-8, and TNF-alpha concentrations were measured by enzyme-linked immunosorbent assay (ELISA) in sputum supernatant. In 17 firefighters, baseline sputum IL-10 concentrations were 57.0 +/- 56.8 pg/L, and declined to 16.9 +/- 27.2 pg/L following overhaul (p =.02). No significant changes were observed in sputum IL-8 and TNF-alpha concentrations. Forced vital capacity (FVC) declined significantly in study participants following overhaul. Serum concentrations of Clara-cell protein and surfactant-associated protein A increased significantly following overhaul, indicating increased lung permeability. IL-10 concentrations appear to be exquisitely sensitive to smoke, and studies of IL-10 in sputum should control for recent exposure. Reduced suppression of inflammation by IL-10 may be a mechanism by which low-level smoke exposure causes lung injury.

Serum pneumoproteins: a cross-sectional comparison of firefighters and police.

BACKGROUND: Serum pneumoproteins provide a measure of the permeability of the lower respiratory tract, and have shown promise as a biomarker of acute and chronic exposure to respiratory toxicants. METHODS: To evaluate the effects of chronic occupational smoke exposure, 105 firefighters were compared with 44 police controls in a cross-sectional study using spirometry, diffusing capacity of the lung, serum Clara cell protein (CC16), and serum surfactant-associated protein A (SP-A) measurements. RESULTS: There were no significant differences in age, gender, height, spirometry (FVC and FEV(1)), and diffusing capacity between the two groups. Serum SP-A was lower in firefighters (260.1 +/- 121.2 microg/L) than police (316.0 +/- 151.4 microg/L, P = 0.019). Serum CC16 was also lower in firefighters (8.39 +/- 3.11 microg/L) than police (10.56 +/- 4.20 microg/L, P < 0.001), although this difference lost statistical significance when adjusted for confounders. CONCLUSIONS: Firefighters have lower serum concentrations of SP-A than do police. Although the clinical significance of this finding is presently unknown, SP-A deserves further study as a biomarker of toxic exposure to the lower respiratory tract.