CELLULARITY AND CELL PROLIFERATION RATES IN HUMAN BONE MARROW

Publisher Website
Google Scholar
Abstract
In a group of 12 patients without haemato‐logical diseases the total number of erythroblasts has been estimated with a 59Fe‐dilution technique including the blocking of 59Fe recirculation by carrier‐iron injections. The total number of proerythroblasts, basophilic, polychromatic and orthochromatic erythroblasts, was estimated on the basis of the total erythroblast number and a marrow differential count and was found to average altogether 3.4 × 109/kg b.wt. The total daily erythrocyte production was estimated by the alveolar carbon monoxide method. Based on the above data the generation times for the various erythroblasts were calculated to be about 11 hours for the most immature and 26 hours for the most mature. The transit time of the orthochromatic erythroblasts was estimated to be 20 hours and that of marrow reticulocytes 51 hours. The total marrow transit time from proerythroblast to circulating reticulocyte was calculated to be 124 hours or about 5 days. Simultaneously in vitro labelling of the erythroblasts with tritium labelled thymidine (H3TDR) was studied. Of the basophilic erythroblasts 70% were labelled, but only 30–40% of the proerythroblasts and the polychromatic erythroblasts. No simple parallelism is thus found with this technique between the labelling index and the generation time.