title: Xanthine:acceptor oxidoreductase activities in ischemic rat skin flaps.
abstract: Xanthine:acceptor oxidoreductase activities were assayed in free skin flaps following prolonged preservation. In normal rat skin, xanthine dehydrogenase transfers electrons to NAD+ and accounts for 73% of total oxidoreductase activity, and xanthine oxidase transfers electrons to molecular oxygen and accounts for the remaining 27%. Xanthine oxidase activity increased significantly in skin flaps during ischemia: approximately 30 and 100% increases after 6 and 24 hr of ischemia, respectively. Allopurinol inhibited xanthine oxidoreductase activity: free skin flaps obtained from allopurinol-treated animals exhibited a low level of xanthine oxidoreductase activity throughout the period of preservation. Systemic allopurinol significantly improved the survival rate from 32 to 75% of free flaps transferred after 24 hr of preservation at room temperature. These observations suggest that the xanthine oxidase system is a major source of oxygen free radicals following ischemia/reperfusion in skin. The increase in xanthine oxidase is attributable to the conversion of xanthine dehydrogenase to oxidase, a conversion which involves sulfhydryl oxidation in skin flaps.
authors.affiliation: Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: M J
authors.initials: MJ
authors.lastname: Im
authors.forename: J E
authors.initials: JE
authors.lastname: Hoopes
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: P N
authors.initials: PN
authors.lastname: Manson
authors.forename: G B
authors.initials: GB
authors.lastname: Bulkley
mesh_terms: D000493:Allopurinol / Q000494:pharmacology; D000818:Animals; D004229:Dithiothreitol / Q000494:pharmacology; D005260:Female; D006085:Graft Survival / Q000187:drug effects; D007511:Ischemia / Q000201:enzymology*; D007658:Ketone Oxidoreductases / Q000378:metabolism*; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012867:Skin / Q000098:blood supply*; D016038:Skin Transplantation; D013524:Surgical Flaps; D014968:Xanthine Dehydrogenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D010664:Phenylmethylsulfonyl Fluoride; D000493:Allopurinol; D014968:Xanthine Dehydrogenase; D014969:Xanthine Oxidase; D007658:Ketone Oxidoreductases; D004229:Dithiothreitol