Cellularity and cell proliferation rates in human bone marrow. I. An in vivo method to estimate the total marrow cellularity in man.

Abstract

Abstract. The total marrow cellularity, using 59Fe as a marrow label, has been measured by an in vivo technique including suppression of radioiron reutilization by inactive iron. The blocking efficacy was studied from the red cell incorporation of 55Fe given after marrow sampling. The error of the method was approximately 16%. The total number of nucleated bone marrow cells averaged 21 × 109/ kg b.wt. There were 13 × 109 granulocyte precursors, 3.4 × 109 nucleated red cells and 0.016 × 109 megakaryocytes. The marrow reticulocytes averaged 4.6 × 109/kg b.wt., or about 20% of the total marrow cells, which was more than in the circulation (3.1 × 109). The transit time of marrow reticulocytes was calculated to be about 50 hours. About 2 red cells and 400 platelets were produced for every granulocyte and each megakaryocyte produces approximately 300 platelets/day. The total volume for erythro‐, granulo‐ and megakaryopoietic marrow cells was approximately 500 ml. The erythroid marrow was calculated to be able to expand maximally by a factor of 10.