title: Differences in radiation response between cells in S-phase and non-S-phase cells of the granulocyte/macrophage progenitor (GM-CFC) compartment.
abstract: Studies were performed to investigate the radiation response of granulocyte/macrophage progenitor cells from canine bone marrow in different proliferative states, and in which way it will change if the S-phase cells are eliminated from the irradiated populations. To obtain progenitor cells of different proliferative states, bone marrow cell suspensions were kept in liquid cultures for 1 or 3 days in the presence of colony stimulating activity. Radiation dose response curves were determined (a) for the total population of progenitor cells under normal conditions (fraction of cells in S-phase 35%), (b) in a state of rapid cycling (fraction of S-phase cells 53% to 57%), and (c) after sterilization of S-phase cells by pretreatment with 3H-thymidine. The rapidly proliferating progenitor cells showed a strong decrease in their radiosensitivity (D0 = 0.84 Gy) within the first day in suspension culture when compared to the normal population (D0 = 0.50 Gy). The cell populations from which the S-phase cells had been eliminated were found more sensitive than the respective total populations (D0 values in the range from 0.44 Gy to 0.50 Gy). The D0 values for the S-phase cells were between 0.57 Gy and 1.13 Gy depending on the proliferative state of the cell populations. These data indicate that granulocyte/macrophage progenitor cells during progression through the S-phase become less radiosensitive than they are in other phases of the cell cycle.
authors.affiliation: Institute of Occupational and Social Medicine, University of Ulm, Donau, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Nothdurft
authors.forename: K
authors.initials: K
authors.lastname: Baltschukat
authors.forename: C
authors.initials: C
authors.lastname: Selig
mesh_terms: D000818:Animals; D004285:Dogs; D006098:Granulocytes / Q000166:cytology / Q000528:radiation effects*; D066298:In Vitro Techniques; D008264:Macrophages / Q000166:cytology / Q000528:radiation effects*; D016196:S Phase / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000528:radiation effects*