title: Differential effect of L-histidine in human lymphocytes damaged by different oxygen radical producing systems.
abstract: The effect of histidine on damage induced by oxygen radicals was studied in peripheral blood lymphocytes treated with free oxygen radical-inducing agents: hydrogen peroxide, xanthine oxidase plus hypoxanthine, bleomycin and gamma-rays. L-Histidine, at a concentration of 1 mM, was found to potentiate both cell killing and inhibition of PHA-stimulated cell division brought about by hydrogen peroxide or xanthine oxidase plus hypoxanthine. In contrast, L-histidine did not affect gamma-ray- or bleomycin-induced cell killing and inhibition of PHA-stimulated cell division. We suggest that L-histidine potentiation of cell damage is mainly mediated by interaction of the amino acid with hydrogen peroxide and/or iron rather than with other reactive oxygen species. In addition, these results also indicate that hydrogen peroxide produced by gamma-radiation- or bleomycin-treated cells plays no role in the toxic effects elicited by these agents.
authors.affiliation: Istituto di Istologia ed Embriologia Generale, Università di Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Marini
authors.forename: F
authors.initials: F
authors.lastname: Frabetti
authors.forename: G
authors.initials: G
authors.lastname: Zunica
authors.forename: G
authors.initials: G
authors.lastname: Brandi
authors.forename: O
authors.initials: O
authors.lastname: Cantoni
mesh_terms: D000328:Adult; D001761:Bleomycin / Q000633:toxicity; D002455:Cell Division / Q000187:drug effects* / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D004247:DNA / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage; D004357:Drug Synergism; D005609:Free Radicals / Q000378:metabolism / Q000633:toxicity; D005720:Gamma Rays; D006639:Histidine / Q000378:metabolism / Q000633:toxicity*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000633:toxicity*; D007501:Iron / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects* / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D017382:Reactive Oxygen Species / Q000378:metabolism / Q000633:toxicity*
chemical_list: D005609:Free Radicals; D017382:Reactive Oxygen Species; D001761:Bleomycin; D006639:Histidine; D004247:DNA; D006861:Hydrogen Peroxide; D007501:Iron