title: Chemical radioprotection of hemopoietic colony-forming cells: comparative effect of AET, anoxia, and urethan.
abstract: The bone marrow colony-forming unit (CFU) technique of Till and McCulloch was employed to test the radioprotective effect of AET, anoxia, urethan on marrow cells irradiated in vivo. For AET and anoxia, a dose-reduction factor of 1.9 to 2.1 was found. Since the marrow cells were assayed for CFU content immediately after irradiation of the donor, the observed effect can be interpreted as a "true" radiation dose reduction. By contrast, urethan injection did not increase the survival of marrow CFU assayed immediately after whole-body x-irradiation. However, both urethan and AET afforded radioprotection of endogenous CFU content of spleen and bone marrow, but not of endogenous spleen colony count. It is concluded that the mechanism of radioprotection by urethan is fundamentally different from that of AET or anoxia.
authors: Biological and Medical Sciences Division, U.S. Naval Radiological Defense Laboratory, San Francisco, California, USA.
authors: L J
authors: LJ
authors: Cole
authors: W E
authors: WE
authors: Davis
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000502:physiology / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011837:Radiation-Protective Agents / Q000008:administration & dosage*; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome; D014520:Urethane / Q000008:administration & dosage*; D000338:beta-Aminoethyl Isothiourea / Q000008:administration & dosage*
chemical_list: D011837:Radiation-Protective Agents; D000338:beta-Aminoethyl Isothiourea; D014520:Urethane