title: Induction of DNA double-strand breaks in CHO-K1 cells by carbon ions.
abstract: Radiation-induced DNA double-strand breaks (dsbs) were measured in CHO-K1 cells by means of an experimental approach involving constant-field gel electrophoresis and densitometric scanning of ethidium bromide stained gels. For X-irradiation, an induction efficiency of 36 +/- 5 dsbs (Gy x cell)-1 was determined. With this set-up, the induction of dsbs was investigated in CHO-K1 cells after irradiation with accelerated carbon ions with specific energies ranging from 2.7 to 261 MeV/u. This set of particle beams covers the important linear energy transfer (LET) range between 17 and 400 keV/microns, where maximum efficiencies have been reported for other cellular endpoints like inactivation or mutation induction. For LETs up to 100 keV/microns, RBEs of approximately 1 have been determined, while efficiencies per unit dose decline for higher LETs. No RBE maximum > 1 was found. Data are compared with published results on dsb induction in mammalian cells by radiations of comparable LET.
authors.affiliation: Gesellschaft für Schwerionenforschung, Darmstadt, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Heilmann
authors.forename: G
authors.initials: G
authors.lastname: Taucher-Scholz
authors.forename: G
authors.initials: G
authors.lastname: Kraft
mesh_terms: D000818:Animals; D010582:Bacteriophage lambda; D016466:CHO Cells; D002244:Carbon / Q000737:chemistry*; D006224:Cricetinae; D004249:DNA Damage; D004279:DNA, Viral / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D066298:In Vitro Techniques; D007477:Ions; D018499:Linear Energy Transfer; D014965:X-Rays
chemical_list: D004279:DNA, Viral; D007477:Ions; D002244:Carbon