Faculty Bibliography

Trona (sodium sesquicarbonate) is mined from an underground deposit in Wyoming and processed for use in the manufacture of glass, paper, and detergents, and in chemical applications. Trona dust is alkaline (pH 10.5) and may have an irritant effect on the respiratory airways, mucous membranes, and the skin. One hundred forty-two underground miners and 88 surface workers from one trona facility participated voluntarily in an epidemiologic and clinical study. Their mean age was 37.6 and their mean working period, 10.0 years. One half of the study participants complained of skin symptoms; dermatologic symptoms increased from twofold to fifteenfold after the subjects began trona mining. Trona dermatitis consists of pruritic, erythematous, raised, dry, and fissured lesions commonly affecting the hands, arms, and legs. A dose-response relationship was observed among underground workers. Patch testing with 10% aqueous trona and sodium carbonate was negative, suggesting that the dermatitis was primarily irritant in nature

Antinuclear antibodies (ANA) were detected using a mouse kidney substrate in 69 of 238 (29 percent) underground Utah coal miners at a titer of 1:16. At titers of 1:4 and higher, 52 percent were positive. The majority had a speckled pattern and were not directed against any previously characterized antigens. Fifteen of 28 with high titer ANA had reduced complement. The ANA was more apt to be present in those with coal workers' pneumoconiosis (CWP), and as ANA titer increased, the percentage with CWP increased. The ANA increased with both age and coal mine dust exposure. It is hypothesized that ANA and CWP both result from long-term dust exposure, but that there is insufficient evidence to implicate ANA in the pathogenesis of CWP

A synthetic zeolite and four natural zeolites from the western United States were examined for fibers using a scanning electron microscope. The distributions of fiber sizes were compared to distributions of fiber sizes of erionite and fibrous glass to determine if the fiber sizes were similar to those associated with mesothelioma in humans and animals. Fibers were abundant in two samples of natural erionite, rare in two samples of natural mordenite, and not present in the sample of synthetic mordenite. Although the majority of the erionite fibers were short (less than 8 mu long) and thicker than the tumorigenic erionite (greater than 0.25 mu wide), 6% and 11% of the fibers corresponded to fiber size categories of fibrous glass that have correlated with pleural mesothelioma production in rats. Even a single species of zeolite (erionite) is not uniform in its distribution of fiber sizes. On the basis of fiber size, these natural zeolites should be evaluated because of their potential carcinogenic risk

Trona (sodium sesquicarbonate) is mined from an underground deposit in Wyoming and processed for use in glass, paper, detergent, and chemical applications. Trona dust is alkaline (pH 10.5) and can have an irritant effect on respiratory airways, mucous membranes, and the skin. A study population of 142 underground miners and 88 surface workers from one facility volunteered for an epidemiologic study. Their mean age was 37.6 yr and mean duration of employment was 10.0 yr. The percentage with chronic cough and phlegm was 23%; both symptoms were more common among smokers than nonsmokers. Thirty-three percent of the workers complained of dyspnea when hurrying on level ground or walking up a slight hill. Half of the workers complained of upper respiratory tract symptoms and eye irritation. Both smokers and exsmokers had significant declines of forced expiratory volume in 1 sec (FEV1.0) with age; exsmokers also had declines with work-years when compared to a nonsmoking comparison population. Nonsmokers with personal dust measurements had a significant decline of FEV1.0 related to respirable dust exposure. A shift study of 104 workers revealed a significant fall in FEV1.0 among nonsmokers and surface workers. Significance was approached in the high dust exposure group. An increase in the mean percent predicted forced vital capacity and FEV1.0 was shown for the 125 workers who had a 5-yr follow-up of pulmonary function. There was no correlation between the shift study decrements and the longitudinal 5-yr follow-up. Industrial hygiene dust sampling found elevated levels of total dust but lower respirable dust, with no detectable free silica

Lymphocyte sister chromatid exchange (SCE) frequencies were determined for 12 long-term coke oven workers and 12 other age-matched steelworkers with no coke oven work exposure. All study participants were nonsmokers. The exposed group had a mean of 28.9 years' exposure to the coke oven emissions. SCE frequencies for the exposed individuals ranged from 7.97 to 11.20 SCEs per cell while the control individuals ranged from 6.73 to 10.60 SCEs per cell. The mean SCE frequency for the exposed group was 9.54 +/- SD 1.15 SCEs per cell, and was 14% higher than the 8.35 +/- SD 1.09 SCEs per cell of the control group (p = .016). The long-term exposure to coke oven emissions experienced by the coke oven workers may be the explanation for this small difference

In vitro cytogenetic studies of amosite, chrysotile, and crocidolite asbestos have shown that these fibers may induce chromosome abnormalities and an elevated sister chromatid exchange (SCE) rate in mammalian cells. Twenty-five asbestos insulators (6 with radiographic asbestosis) were compared to 14 controls frequency matched for age and were found to have a marginally increased SCE rate in circulating lymphocytes with increasing years of exposure (P= 0.057). There was a significant association between SCE rate and smoking (P=0.002) after controlling for years of asbestos exposure and age. Smoking asbestos insulators had the highest SCE rate. Sister chromatid exchanges in chromosomes of group A, i.e., the group with the longest chromosomes, were significantly associated with asbestos exposure and cigarette smoking, with an interaction between the two