title: Construction of artificial methemoglobin reduction systems in Hb vesicles.
abstract: The hemoglobin vesicle (HbV) is a red cell substitute encapsulating purified concentrated Hb in a phospholipid vesicle. In order to suppress metHb formation for the long term maintenance of oxygen transporting capability in vivo, thiols (cysteine, Cys; homocysteine, Hcy) were studied as reductants of metHb. Hcy showed a suppressive effect on metHb formation, while Cys adversely accelerates metHb formation at the rate of twice the Hb solution without any reductants. The suppression of Cys-induced metHb formation by the addition of superoxide dismutase (SOD) and catalase indicated that Cys was easily oxidized by oxygen and simultaneously generated a large amount of active oxygens. The rate of metHb formation was influenced by PO2 and pH. Furthermore, the reducing systems (methylene blue (MB), NADH or ascorbic acid) were added to the outer aqueous phase of HbV, and the artificial reduction systems constructed through the bilayer membrane were evaluated.
authors.affiliation: Department of Polymer Chemistry, Waseda University, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takeoka
authors.forename: T
authors.initials: T
authors.lastname: Ohgushi
authors.forename: H
authors.initials: H
authors.lastname: Sakai
authors.forename: T
authors.initials: T
authors.lastname: Kose
authors.forename: H
authors.initials: H
authors.lastname: Nishide
authors.forename: E
authors.initials: E
authors.lastname: Tsuchida
mesh_terms: D001802:Blood Substitutes / Q000138:chemical synthesis* / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism / Q000494:pharmacology; D004396:Coloring Agents / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D004339:Drug Compounding; D005978:Glutathione / Q000378:metabolism / Q000494:pharmacology; D006454:Hemoglobins / Q000187:drug effects / Q000378:metabolism; D006710:Homocysteine / Q000494:pharmacology; D006801:Humans; D008567:Membranes, Artificial; D008706:Methemoglobin / Q000378:metabolism*; D008751:Methylene Blue / Q000494:pharmacology; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000378:metabolism / Q000494:pharmacology
chemical_list: D001802:Blood Substitutes; D004396:Coloring Agents; D006454:Hemoglobins; D008567:Membranes, Artificial; D006710:Homocysteine; D008706:Methemoglobin; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione; D003545:Cysteine; D008751:Methylene Blue