title: Degree of bronchial metaplasia in heavy smokers and its regression after treatment with a retinoid.
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001980:Bronchi / Q000473:pathology*; D020680:Bronchoscopes; D002986:Clinical Trials as Topic; D005050:Etretinate / Q000627:therapeutic use*; D005260:Female; D005336:Fiber Optic Technology; D006801:Humans; D008297:Male; D008679:Metaplasia / Q000188:drug therapy / Q000209:etiology; D008875:Middle Aged; D012907:Smoking; D014212:Tretinoin / Q000031:analogs & derivatives*; D014801:Vitamin A / Q000627:therapeutic use*
chemical_list: D014801:Vitamin A; D014212:Tretinoin; D005050:Etretinate