Bronchoscopy in the European hamster (Cricetus cricetus).

A pediatric bronchoscope was modified for use in the European hamster (Cricetus cricetus) and has been used successfully to obtain biopsy specimens from these animals. Biopsy specimens were obtained by means of small forceps with visual control given by the modified bronchoscope.

Inhalation studies with polyurethane foam dust in relation to respiratory tract carcinogenesis.

Male and female Sprague-Dawley rats were exposed to freshly generated polyurethane foam dusts, in concentrations averaging 8.65 mg/m3 air, for 6 hours daily 5 days a week over a period of 12 weeks. For comparison the same numbers of rats were exposed to titanium dioxide (TiO2) (15.95 mg/m3 air), which is a known inert dust, and to air alone, as controls for the same exposure period. This exposure caused no noticeable changes in appearance, behavior, or body weight. The average lifespan values were within the normal range. A high tumor rate was seen in all groups, with no significant differences among the groups. No indications of a carcinogenic effect of the inhaled dusts on the respiratory tract could be established. The numerous tumors found in the different organs and groups were of a spontaneous nature. The observed lung-reactions are discussed.

The carcinogenic effect of beta-oxidized dipropylnitrosamine in mice. I. Dipropylnitrosamine and methyl-propylnitrosamine.

Di-n-propylnitrosamine (DPN) and methyl-n-propylnitrosamine (MPN) induced mainly respiratory tract neoplasms in female NMRI mice after subcutaneous administration. The majority of tumors occurred in the nasal cavities, although significant incidences were also found in the larynx, trachea and stem bronchi. Treatment with both substances additionally resulted in vascular neoplasms of the liver, while DPN only caused tumors in the pharynx, esophagus and forestomach.