The capacity of hemopoietic cells for colony-formation and the pattern of their differentiation during hypokinesia were studied. The absolute count of colony-forming units (CFU) decreased exponentially during 3 to 30 days. Bone marrow showed a change in the total cell count and a wave-like change in the absolute and relative count of CFU with a maximum on the 1st-3rd and 15th-45th days. Differentiating potentialities of CFU from the spleen and bone marrow were not altered towards erythro-, myelo- and thrombopoiesis. The cell structure of the peripheral blood changed, displaying lymphopenia, transient neutrophil leukocytosis, increase in the percentage content of large lymphocytes and stress-lymphocytes.

Fibroblast colonies (clones) are formed in monolayer cultures of the bone marrow, spleen and thymus cells from adult mice, the colony-forming efficiency (per 105 cells) was 2.2, 0.2 and 0.16, respectively. About 50% of the bone marrow CFU-F were destroyed immediately after the total body irradiation with 150r; the following 6 days the number of CFU-F decreased to 10% of the normal value. The normal level of the CUF-F concentration was reached in the bone marrow on the 25th postirradiation day.

The antigen-binding cell clones and the Ig-positive cells were found and quantitatively assessed in the primary hemopoietic splenic colonies. The data ogtained were analyzed assuming that the ratio of clone of specialized B-cells should reflect the quantitative ration in the corresponding V-genes in the given lymphocyte populations at definite stages of its development. The colonies differed from one another markedly by the curves of inhibition by DNP-lysine of rosette-formation with DNP-erythrocytes, i.e. by the avidity of B-cells of the given specificity. The colonies differed significantly by the ratio of the volumes of the two clone groups (cell with anti-DNP and anti-BE Ig-receptors) between themselves and the combination of the Ig-positive cells. These quantitaive regularities were incompatible with the view that each B-cell had any conceivable set of V-genes, i.e. with the germ-line hypothesis of the antibody and receptor diversity.

The effect of the interval (4-96 hours) between the irradiation of hybrids (CBAXC57BL/6 F1 and the bone marrow transplantation from C57BL/6 mice on the manifestation of allogenic inhibition of the stem cells was studied; in the given donor-recipient model the degree of allogenic inhibition constituted 90%. The bone marrow transplantation 4 to 48 hours after the irradiation failed to influence the number of colonies in the spleen of hybrids F1, but when this transplantation was given 96 hours after the irradiation the colony-forming ability of parental hemopoietic cells regressed to 33%. Remote transplantation had no influence on the number of colonies in the spleen of syngenic recipients.

Radiosensitivity of spleen CFU localized in the bone marrow and in the spleen proved to be the same. Do is about 105--120r for the CFU-forming colonies in the spleen and 120--135r for the CFU-forming colonies in the bone marrow. As suggested, there are two CFU fractions in the bone marrow. One of them is radiosensitive and another--radio-resistant. Chiefly the radiosensitive CFU fraction is the one localized in the spleen.

The treatment in vitro of bone marrow cells in mice by phytohemagglutinin, concanavaline, or antilimphocytic globulin resulted in the suppression of exogenous hemopoietic colonies in the spleen of lethally irradiated (830r) syngenic recipients, whereas lipopolysaccharide, tuberculin, anti-theta serum or nati-gamma-globulin serum exerted no influence on the colony-forming function of hemopoietic stem cells. The morphological analysis of the ratio and cell composition of hemopoietic colonies has revealed no marked differences between the experimental and control groups. The suppression of hemopoietic stem cells by mitogens might be due both to their direct effect and indirect one, possibly, through a humoral factor.

The spleen (2/3) was removed in CBA male mice (the 1st group); in the 2nd group the bone marrow from the right posterior shin was removed. The hemopoietic splenic colonies were counted on the 8th day after the lethal irradiation and injection of 1 X 10(-6) nucleated cells of the intact spleen. A significant increase of the number of colonies in comparison with their number in control intact mice was observed. The authors suppose that this increase could also be caused by the local influence of the regenerating stroma of the spleen and by some stimulating factor discharge by the regenerating hemopoietic tissue.

The electrophoretic pattern of glucose-6-phosphate dehydrogenase (G-6-PD) was studied in 60 intergeneric fox hybrids (Alopex lagopus X Vulpes vulpes), 33 females and 27 males. It is shown that the structural gene for G-6-PD, designated as Gpd, is located on the X-chromosome in both Arctic and silver foxes. Analysis of G-6-PD in the erythrocytes of hybrid females demonstrated that the phenotypic expression of parental alleles at the locus Gpd varied considerably: from 1:1 to the hemizygous manisfestation of an allele of either the Arctic or silver fox. It is suggested that the variable quantitative expression of the alleles at the locus Gpd in hybrid females is related to the presence of two cell populations having in an active state either the X-chromosome of the Artic or silver fox. It is also assumed that the size of two cell populations is significantly influenced by the different relations in the group of initiator (stem) cells, which possess different X-chromosomes in an active state, which has been established in early embryogenesis. In the case of erythrocytes, it is found that the number of initiator (stem) cells for erythrocytes comprises 5-6.

Measurements of colonies diameter in monolayer cultures of bone marrow in 21 patients with lymphogranulomatosis (an active process and the state of clinical remission) and in 5 healthy donors with subsequent mathematical processing of the results indicated that in most patients with active lymphogranulomatosis and in some patients being in the state of clinical remission, in contrast to healthy donors, the distribution of colonies in diameter is not in accord with the normal law of the distribution. The reliability of the phenomenon observed and its significance for recognition of active lymphogranulomatous process are supported by an additional mathematical analysis.