METHODS

Materials and equifiment. DL-Epinephrine and cytochrome G type III were obtained from Sigma Chemical Company and xanthine oxidase was obtained from Worthington Biochemical Corporation. SOD, purified from bovine liver, was obtained from Diagnostic Data Incorporated. Liquid oxygen came from North Carolina Welding Supply. Equipment used included a Beckman Acta CIII recording spectrophotometer, a Shimadzu model MPS-50L dualbeam recording spectrophotometer, a Gilford 300-N spectrophotometer, Dwyer Visi Float air flowmeters, a Corning model 165 pH blood gas analyzer, and a Branson model 140-D sonifier.

Animals. We used specific pathogen-free male rats (Charles River) which weighed 250-350 g. TO establish that the procedures did not lead to lung infection, 20 rats were removed from the barrier and 1.0 were kept in air for 37 days while 10 were exposed to 85% oxygen for 7 days and then kept in air for 30 days. At the end of this 37-day period, fluid obtained by bronchial lavage of all 20 animals was cultured, and the lungs were examined by light microscopy. Cultures were done for viral, bacterial, and mycoplasma pathogens and none was found. The lungs had no histological evidence of infection. Hartley guinea pigs were obtained from Camm Research, Syrian hamsters were obtained from the Lakeview Hamster