A Comparison of the Three <i>in vivo</i> Assays for Haemopoietic Stem Cells

Abstract

The effect of a proliferation-independent (nitrogen mustard) and 4 proliferation-dependent (methotrexate, vinblastine, cyclophosphamide and 5-fluorouracil) cytotoxic agents has been investigated, concurrently, on the 3 in vivo assays (colony-forming units, erythroid repopulating ability and granulocytic repopulating ability) for haemopoietic tem cells. These preliminary results show that the proliferation-dependent agents produce different responses in the 3 assays consistent with the presence of 3 different cell populations proliferating at different rates. The findings tend to support published hypotheses on the existence of 3 different stem cell populations (possibly ‘committed’ stem cells)

Effect of Daily Administration of Cytotoxic Drugs on the Erythroid and Granulocytic Repopulating Ability of Rat Bone Marrow

“…Differ ences in the sensitivity of erythroid and granulocytic repopulating cells and pluripotential stem cells (CFUs) after single doses of cytotoxic agents indicate that these are distinct populations of precursor cells and it has been suggested that the repopulating cell compartments are composed of commit ted stem cells [Dunn and Constable, 1973]. Further evidence for the separate identity of erythroid and granulocytic repopulating cells has been provided by the present study.…”