Abstract
1 Cell proliferative activity of atypical bronchioloalveolar epithelia in lung fibrosis cases treated with bleomycin (BLM) or radiation was investigated by studying the his tochemistry of the argyrophil nucleolar organiser regions (AgNORs) and proliferating cell nuclear antigen (PCNA).
2 Five and 14 autopsy cases of individuals who died of pulmonary fibrosis, caused by BLM treatment and irra diation respectively, were compared with (i) six control subjects who proved to have no apparent fibrosis of the lung at autopsy and (ii) four lung squamous cell carci noma cases.
3 Histopathologically, both the BLM-treated and irradiat ed cases showed extensive collapse of the lung caused by severe fibrosis, although proliferative epithelial lesions such as atypical bronchioloalveolar hyperplasia and squamous metaplasia were more prominent in the former.
4 The mean AgNOR numbers in both atypical hyper plasias and metaplasias, of either BLM or irradiation cases, were significantly higher than in control bronchi oloalveolar epithelial areas, whereas they were lower than in the lung cancers. Data for PCNA-labelling indices were in line with those for AgNORs.
5 The results indicate that atypical hyperplastic lesions in the bronchioloalveoli arising during the fibrosing process as induced by BLM, and by irradiation, are highly proliferative.
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