Pulmonary arteriolar muscularization in coal workers' pneumoconiosis and its correlation with right ventricular hypertrophy.

The relationship between the thickness of the walls of small pulmonary arteries (the medial wall thickness as a percentage of external diameter, percentage of medial thickness) in coal miners and control subjects were studied using morphometric techniques and correlated with the degree of right ventricular hypertrophy, severity of coal workers' pneumoconiosis, emphysema, and other chronic lung diseases. Pulmonary arteries less than 100 microns in external diameter were identified and the external diameter, medial thickness, and intimal thickness were quantitatively measured in the lung tissues of 57 coal miners and 15 control subjects with and without other chronic lung diseases. Coal workers' pneumoconiosis, emphysema, and right ventricular hypertrophy were assessed uniformly in all cases. The arterial wall thickness correlated with right ventricular hypertrophy, progressive massive fibrosis, and other chronic lung diseases. Severity of emphysema also showed a weak correlation. Although the functional significance of these findings is not known, we conclude that the muscularization of pulmonary arterioles provides a structural basis for the development of right ventricular hypertrophy in coal miners.

Frequency of black pigment in livers and spleens of coal workers: correlation with pulmonary pathology and occupational information.

Histologic sections of liver and spleen from 99 retired coal workers and nine non-coal workers were obtained at autopsy and scored for black pigment. Pigment was minimal in the non-coal workers, with the exception of one person with silicosis. Moderate or heavy pigment was seen in 10.4 per cent of liver sections and 19.5 per cent of spleen sections from coal workers. The extrapulmonary pigment was not associated with any pathologic tissue response. Information on pulmonary pathology and occupational exposure to dust was available for most workers. Highly significant positive correlation was found between the severity of pneumoconiosis and the black pigment score in both liver and spleen; the correlation between emphysema and pigment score was lower, but still significant for liver. Significant positive correlations were found between years spent underground, years of retirement, and age at death versus pigment scores. Significant negative correlation was found between smoking and pigment. The positive association of extrapulmonary pigment with age at death, years of underground mining, and severity of pneumoconiosis suggests that cumulative lifetime exposure to coal mine dust may be the most important factor in the release of dust into the general circulation.