Nature of stromal elements of the human bone marrow capable of releasing humoral stimulators of precursor cells of granulomonocytopoiesis

: Whole bone marrow fragments of trepanobiopsies of the upper flaring portion of the ilium were cultivated over 1 to 8 weeks in a liquid phase of the agar drop-liquid medium system. Fifty-two hematological patients and controls were examined in order to study the character of regeneration of different stromal cells and their role in the production of stimulants of precursor cells of granulomonocytopoiesis. It was shown that during cultivation of bone marrow fragments precursors of the stromal cells form a monolayer at the dish bottom, forming a capsule around the fragments and proliferating inside the medullary lacunae. Endosteum is the main source of the regeneration of the stromal elements. The studies did not reveal any relationship between the colony-stimulating activity of the trepanobiopsies and the area occupied in them by sinuses, fibrous and osseous tissue. A positive correlation was established between the CSA and the number of fatty cells. The magnitude of the area of the stromal cell monolayer did not influence colony formation. Based on the data obtained the authors suggest that fatty acids are the main producers of the CSA within the system under consideration.