Endosteal marrow: a rich source of hematopoietic stem cells.

Hematopoietic cells isolated from the endosteal bone surface, that is,the endosteal marrow cells, were found to consist mainly (60 to 80 percent) of lymphoid and late-stage normoblast-like cells. Unlike the cells they resemble, the endosteal marrow cells showed an affinity for Sudan black, demonstrable nucleoli (Feulgen reaction), and an absence of hemoglobin. Assays showed that over one-half of the endosteal marrow cell population may be the colony-forming units, the CFU-S of Till and McCulloch. Thus, high concentrations of stem cells could be obtained from the endosteal bone surface by means of the present isolation technique.