title: Effect of varying the concentration of damage restituting species in the radical repair model.
abstract: From analytical expressions derived for the radical-repair (competition) model describing the relationship between cellular radiosensitivity and oxygen concentration, "K-curve" behavior has been quantified as a function of the concentration of the species S which restitutes the radiation-induced radicals to their original molecular configuration. If these species are identified with thiols, K-curves modified by fractionally depleting [S] through calculation can be compared with experimental data where cells have their thiols depleted using various means, for example, by chemical agents or by the use of cells with decreased thiols because of genetic deficiency. Families of curves have been calculated related both to the S-depleted and the non-S-depleted hypoxic control, the latter of which is used to calculate enhancement ratios. Comparison of the model with experimental data is made.
authors.affiliation: Department of Radiation Medicine, Massachusetts General Hospital, Boston 02114.
authors.forename: E R
authors.initials: ER
authors.lastname: Epp
authors.forename: K D
authors.initials: KD
authors.lastname: Held
authors.forename: E P
authors.initials: EP
authors.lastname: Clark
authors.forename: J E
authors.initials: JE
authors.lastname: Biaglow
mesh_terms: D000818:Animals; D002477:Cells / Q000528:radiation effects; D004260:DNA Repair; D008954:Models, Biological; D010100:Oxygen / Q000502:physiology; D011836:Radiation Tolerance; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D013438:Sulfhydryl Compounds; D010100:Oxygen