ENERGY-DISPERSIVE X-RAY-ANALYSIS AND SCANNING ELECTRON-MICROSCOPY OF PLEURA - STUDY OF REFERENCE, EXPOSED NON-PNEUMOCONIOTIC, AND SILICOTICPOPULATIONS

Inorganic element content in pleura and lung was studied by energy-dis persive X-ray analysis (EDXA) and scanning electron microscopy (SEM) i n reference, exposed non-pneumoconiotic, and silicotic populations. Sa mples of parietal pleura, visceral pleura, and lung in 11 subjects wit h no measurable exposure to inorganic dust and of visceral pleura and lung samples of 10 exposed non-pneumoconiotic individuals and eight si licotic patients were examined. Constant depositions of silicon and ca lcium were detected in visceral pleura, parietal pleura, and lung of t he 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 sil icotic patients and, less frequently, in the reference group. There wa s no difference in silicon content between parietal and visceral pleur a in the reference group. Silicon content in silicotic patients was hi gher 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, respecti vely) than in the reference group. Comparison of the silicon content i n pleura between silicotic and exposed non-pneumoconiotic subjects sho wed a nonsignificant probability of difference (p = 0.052), whereas th ere were no differences with respect to the silicon content in lung. T here were no differences in the pleural and lung silicon content betwe en the exposed non-pneumoconiotic and reference groups. Considering di fferent pleural and lung silicon content cut-off levels, EDXA and SEM appear to be able to differentiate pleura and lung of silicotic patien ts from that of persons with no significant occupational exposure and of persons with significant occupational exposure.