The Kinetics of the Normal, the Megaloblastic and the Sideroachrestic Erythropoiesis Estimated by Colchicine Blocking In Vitro

By adding colchicine to bone marrow cultures we developed further parameters for kinetics in normal, megaloblastic and sideroachrestic bone marrow. The increased regeneration in megalopoiesis is demonstrated by an increased mitotic index, an increased stathmokinetic index, a shortened cell doubling time and the prolongation of the divisable pool to the oxyphile erythroblasts which only mature in the normal state. To get ineffective erythropoiesis, the maturation in vivo must have been delayed by an increased number of generations up to the formation of megalocytes. From the stathmokinetic test in vitro, the maturation in megalopoiesis is accelerated as a result of the inhibition of α-2 α-divisions. In normal erythropoiesis stopping mitoses by colchicine probably causes a delayed maturation because the next maturation stage cannot be reached without the regular n-2n-division. In sideroachrestic anemia, the maturation behaves normally but the stathmokinetic test is very high. We conclude that the maturation and mode of division in sideroachrestic anemia is nearly normal.