[Cellular structures formed during bone marrow cultivation in agar].

The growth-enhancing effect and the differentiation of colonies formed by native and frozen-thawed myelokaryocytes in semiliquid agar were observed over a period from the 2nd to the 28th day. The cultivation of bone marrow in agar was shown to form colonies consisting of haemopoietic cells as well as of stromal elements. Under the cultivation of frozen-thawed bone marrow, the retardation of proliferative activity of growing cells was observed within up to 4 days. Later on the proliferative character and the rate of the myelokaryocytes of both the types were seen identical. The question of a possible existence of haemopoietic tissue and stromal elements in the progenitor cells of normal bone marrow is being discussed.