Quantification of the nuclei of human bronchial epithelial cells from electron micrographs for radon risk analysis

Abstract

Lung cancer in either smokers or in uranium miners exposed to radon occurs preferentially in the epithelium of the bronchi (airway generations 2 to 6). Accurate carcinogenesis risk/dose modeling requires quantitative data on normal bronchial epithelial parameters including: (a) the average number and volume densities (VD) of the nuclei of the possible target cell types and (b) the distances to the free surface of the nuclei of each type. Current dose models use data from an inadequate 1972 light microscopic study. Since smoking and radon effects may be synergistic, these parameters of the bronchi of smokers and non-smokers should be compared.Human bronchial specimens (72) dissected by airway generation were obtained from non-involved areas of lungs/lobes removed for various pathologies (16 smokers, 8 non-smokers). Samples were fixed with 2% glutaraldehyde, 0.1 M cacodylate, 0.1M sucrose for routine TEM (graded ethanols, Epon embedding, lead and uranyl staining) and sections were examined on a JEOL 1200 EX at l,000x at 60 KV.