Hematopoietic stem cells: effect of preirradiation, bleeding, and erythropoietin on thrombopoietic differentiation.

A method of measuring differentiation of stem cells towards platelets is described using syngeneic bone marrow injected into lethally irradiated mice. Fourteen days after such injection, the platelet counts are found to be proportional to the number of bone marrow cells injected and can be used as a measure of platelet progenitors. Perturbation of the milieu in which the transplanted marrow is placed by host preirradiation, bleeding, or erythropoietin administration leads to enhanced thrombopoiesis.

Enhanced erythropoiesis with concomitant diminished granulopoiesis in preirradiated recipient mice. Evidence for a common stem cell.

Three different methods of measuring the proliferative capacity of transplanted mouse bone marrow were used to study the effects of preirradiation of the recipient. Recipient mice were exposed to 700 R and given graded numbers of syngeneic bone marrow. 7 days were allowed for proliferation of these cells, and then the granulocytic or erythrocytic progeny was measured.