title: Inert gas enhancement of superoxide radical production.
abstract: Two free radical generating systems, xanthine oxidase/hypoxanthine or phenazine methosulfate/NADH, were exposed to air plus He, N2, or Ar at partial pressures ranging from 0.2 to 6.0 MPa, and the rates of production of superoxide, hydroxyl, singlet O2, and H2O2 were measured. All three inert gases acted similarly to enhance the production of superoxide radicals by facilitating interactions between iron and H2O2, or O2 and organic radicals. These reactions occurred at quite low gas partial pressures, only 0.28 MPa, and hydrostatic pressures of up to 6.0 MPa had no effect on radical reactions. Enhanced radical production may be the basis for the inhibition of cellular growth mediated by inert gases, and inert gas enhancement of O2 toxicity.
authors.affiliation: Institute for Environmental Medicine, University of Pennsylvania, Philadelphia 19104-6068.
authors.forename: S R
authors.initials: SR
authors.lastname: Thom
mesh_terms: D004837:Epinephrine / Q000737:chemistry; D005609:Free Radicals; D006861:Hydrogen Peroxide / Q000737:chemistry; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000737:chemistry; D008773:Methylphenazonium Methosulfate / Q000737:chemistry; D009243:NAD / Q000737:chemistry; D005741:Noble Gases / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013481:Superoxides / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000737:chemistry
chemical_list: D005609:Free Radicals; D007042:Hypoxanthines; D005741:Noble Gases; D009243:NAD; D013481:Superoxides; D008773:Methylphenazonium Methosulfate; D019271:Hypoxanthine; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase; D010100:Oxygen; D004837:Epinephrine