[en] Conditions for large scale production of monoclonal antibodies (monoAB) on mice hybrids were determined: irradiation dose, amount of introduced hybridoma cells, possible substitution of imported pristane for Soviet-produced vaseline oil or a mixture thereof. DMSO did not exert toxic action neither on the cell itself, nor on the development of ascytic tumor in mice after thawing of cryopreserved cells. This enabled to abstain from washing of DMSO off the introduced cells. A simple method for enhancing the monoAB yield - acquisition of the washing-out solution for increased efficiency of large scale production - was developed and tested

[en] The ability of yolk sac and primary bone marrow cells of the quail to form hemopoietic colonies at 6 hours of incubation (i.e. before establishment of circulation) was studied in the bone marrow of 3-week sublethally irradiated chickens. The experiments were besed on the possibility of differentiating between quail and chicken cells from the natural cell marker (Pheulgen-positive nucleus). The number of hemopoietic colonies produced by cells transplanted from the primary bone marrow was three times greater than that consequent on transplantation of yolk sac cells. With the given dose of irradiation the bone marrow shows about 75% exogenous (quail) and 25% endogenous (chicken) hemopoietic colonies

[en] During serial passages of hemopoietic tissue as a whole ectopic hemopoietic site under renal capsule of irradiated mice gradual decrease of proliferative potential of CFU_s has been observed. The results suggest that the most probabla cause of such decline is random loss of precursor cells with high but limited proliferathve potential during serial passages of hemopoietic tissue

[en] Forty-seven individual hemopoietic cell clones bearing unique radiation markers were studied in long-term bone marrow cultures. Throughout cultivation clones appeared at different times, from 1 to 12 weeks after explantation, survived during 1-10 more weeks, and were characterized by marked variability in size. Usually, the number of metaphases peculiar to an individual clone rapidly increased, achieved maximum, and then underwent a decline. Cells of reliably disappearing clones were never seen again. The experimental results provide further evidence for the model of hemopoiesis by clonal succession

[en] It has been revealed by competitive repopulation assay that hemopoietic stem cells capable of supporting long-term hemopoiesis in the culture failed to regenerate after irradiation. 19 weeks after irradiation with 4 Gy the content of hemopoietic stem cells was 0.5% normal, while regeneration of CFUs was achieved up to subnormal level