Energy-dispersive X-ray analysis and scanning electron microscopy of pleura. Study of reference, exposed non-pneumoconiotic, and silicotic populations.

Inorganic element content in pleura and lung was studied by energy-dispersive X-ray analysis (EDXA) and scanning electron microscopy (SEM) in reference, exposed non-pneumoconiotic, and silicotic populations. Samples of parietal pleura, visceral pleura, and lung in 11 subjects with no measurable exposure to inorganic dust and of visceral pleura and lung samples of 10 exposed non-pneumoconiotic individuals and eight silicotic patients were examined. Constant depositions of silicon and calcium were detected in visceral pleura, parietal pleura, and lung of the reference group and in visceral pleura and lung of the exposed non-pneumoconiotic and silicotic groups. Other elements, such as aluminum and iron, were also detected in the exposed non-pneumoconiotic and silicotic patients and, less frequently, in the reference group. There was no difference in silicon content between parietal and visceral pleura in the reference group. Silicon content in silicotic patients was higher and more irregularly distributed in the pleura (p = 0.005 and p < 0.01, respectively) and in the lung (p = 0.005 and p < 0.01, respectively) than in the reference group. Comparison of the silicon content in pleura between silicotic and exposed non-pneumoconiotic subjects showed a nonsignificant probability of difference (p = 0.052), whereas there were no differences with respect to the silicon content in lung. There were no differences in the pleural and lung silicon content between the exposed non-pneumoconiotic and reference groups.(ABSTRACT TRUNCATED AT 250 WORDS)