title: Ascorbate, added after irradiation, reduces the mutant yield and alters the spectrum of CD59- mutations in A(L) cells irradiated with high LET carbon ions.
abstract: It has been reported that X-ray induced HPRT- mutation in cultured human cells is prevented by ascorbate added after irradiation. Mutation extinction is attributed to neutralization by ascorbate, of radiation-induced long-lived radicals (LLR) with half-lives of several hours. We here show that post-irradiation treatment with ascorbate (5 mM added 30 min after radiation) reduces, but does not eliminate, the induction of CD59- mutants in human-hamster hybrid A(L) cells exposed to high-LET carbon ions (LET of 100 KeV/microm). RibCys, [2(R,S)-D-ribo-1',2',3',4'-Tetrahydroxybutyl]-thiazolidene-4(R)-ca riboxylic acid] (4 mM) gave a similar but lesser effect. The lethality of the carbon ions was not altered by these chemicals. Preliminary data are presented that ascorbate also alters the spectrum of CD59- mutations induced by the carbon beam, mainly by reducing the incidence of small mutations and mutants displaying transmissible genomic instability (TGI), while large mutations are unaffected. Our results suggest that LLR are important in initiating TGI.
authors.affiliation: Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Akiko
authors.initials: A
authors.lastname: Ueno
authors.forename: Diane
authors.initials: D
authors.lastname: Vannais
authors.forename: Marek
authors.initials: M
authors.lastname: Lenarczyk
authors.forename: Charles A
authors.initials: CA
authors.lastname: Waldren
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D018957:CD59 Antigens / Q000235:genetics*; D002244:Carbon; D006224:Cricetinae; D003545:Cysteine / Q000031:analogs & derivatives; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D006822:Hybrid Cells / Q000528:radiation effects*; D007477:Ions; D018499:Linear Energy Transfer; D009154:Mutation / Q000187:drug effects*; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D018957:CD59 Antigens; D016166:Free Radical Scavengers; D007477:Ions; D013844:Thiazoles; D053778:Thiazolidines; C070066:2-(1',2',3',4'-tetrahydroxybutyl)thiazolidine-4-carboxylic acid; D002244:Carbon; D003545:Cysteine; D001205:Ascorbic Acid