[An analysis of the cell composition of the reserve population in the colony-forming unit system of bone marrow fibroblasts under the action of ionizing radiation].

The system of stromal cell precursors--colony-forming units of fibroblasts (CFUf) of the bone marrow possesses a significant reserve population which is mobilized in exposure to extreme effects, after irradiation in the given case. This compensatory-adaptational reaction is evidently one of the factors of optimization of postradiation hematopoiesis restoration. Analysis of the cell composition of the CFUf reserve population showed that it does not differ basically from the population tested under normal conditions. Differences are also noted, however: two CFUf pools are distinguished in the reserve population distinctly which possess the largest cell reserve--in the region of the small and large clones.