Radiosensitivity of colony-forming units of dog bone marrow in agar cultures

The radiosensitivity of colony-forming units in dog bone marrow was determined by a modified method of cloning hematopoietic cells in semisolid agar gel in diffusion chambers in vivo. The dose of radiation whose action was followed by preservation of 37% of the objects (D_o) was 144±14.8 rad (n=0.8) for committed precursor cells of granulocytopoiesis (CFUc) and 468±35.8 rad (n=0.9) for precursor cells forming stellate colonies of fibroblast-like cells (CFUf). It is concluded that the CFUf belong to the class of stromal precursors of hematopoietic organs. This system is suitable for the simultaneous study of hematopoietic and stromal precursor cells in dogs.Laboratory of Bone Marrow Culture and Transplantation, Central Institute of Hematology and Blood Transfusion, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Fedorov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 4, pp. 340–342, April, 1979.