[The characteristics of the hematopoietic cells forming colonies on cellulose acetate membranes and their distinctions from other clonogenic cells].

In order to characterize hemopoietic cells forming colonies on membranes of cellulose acetate (CFU-acm) implanted into the peritoneal cavity of mice, we studied the effect of factors stimulating and inhibiting granulocytopoiesis on these cells. Proliferation of CFU-acm can be controlled by humoral factors and this allows us to conclude that they are not identical to CFUs and probably belong to the compartment of early hemopoietic cells of the granulocyte series. We also present evidence for fractional composition, ultrastructure and bone marrow origin of cells belonging to the layer providing for hemopoietic microenvironment for the resulting foci of hemopoiesis; we also present evidence for the role of fibroblasts (fibroblast-like cells) in the maintenance of hemopoiesis.

[Precursor cells of newly formed connective tissue in inflammatory foci in various organs in mice].

The origin of fibroblast-like cells of the capsule around a foreign body in the spleen, liver, peritoneal cavity, subcutaneous connective tissue of mice, the localization of cells-precursors, their proliferative potencies and the ability to migrate through blood were studied using 3H-thymidine autoradiography. Precursors of the inflammation focus cells (irrespective of localization) reproduce intensively outside the limits of intraorganic connective tissue, supposedly, in hemopoietic organs of the bone marrow type and migrate, through the blood channel, into tissues (inflammation foci), where they terminate their differentiation.