| Abstract: | Spleen colonies in the irradiated mice are produced by both stem cells and by their more differentiated progeny. In the latter case the colonies are transitory, ceasing 10-11 days after cell injection. The transitory colonies may be the cause of systematic artifact during the determination of stem cell proliferation. It was shown in particular that the proliferation of stem cells after sublethal irradiation remains the same, while higher rates of suicide are determined by the death of the precursors of the transitory colonies. At the same time higher proliferation of stem cells is not artifact in lethally irradiated animals and is also detectable after exclusion of the effects of the precursors of the transient colonies. |
