Effect of cytokine treatment (granulocyte colony-stimulating factor and stem cell factor) on hematopoiesis and the circulating pool of hematopoietic stem cells in mice.

The mobilization of hematopoietic stem cells (HSCs) into the peripheral blood of mice was induced by recombinant human granulocyte colony-stimulating factor (rhG-CSF) (250 microgram/kg/d) alone or combined with recombinant rat stem cell factor (rrSCF) (34 microgram/kg/d), injected subcutaneously (s.c.) once a day for 10 and 17 days.

[Study of hematopoietic stem cell pool maintenance in successive transplantations using a quantitative method of assessment].

The ability of transplantable hemopoietic stem cells (HSC) to maintain their pool was studied using successive bone marrow transplantations with quantitative evaluation of hemopoiesis restoring units (HRU) in each transfer. The number of injected HRU increased (3.6-48.

[Hematopoietic stem cells in mice during embryonic development preceding the establishment of liver hematopoiesis].

We studied the time course of appearance of CFUs (7-8 days old) in embryos of (C57B1/6 x CBA)F1 mice from the 8th day of embryonic development. Significant amounts of CFUs could be detected from the 10th day of development, initially in the body of the embryo from the stage of 30-33 pairs of somites, then in the yolk sac and still later, from the stage of about 40 pairs of somites, in liver anlage. CFUs could not be reliably detected until the 9th day of development either in the embryo itself or in the yolk sac.

[Quantitative determination of transplantable hemopoietic stem cells by limiting dilution method].

The concentration of hemopoiesis restoring units (HRU) in bone marrow of mice was assayed by using the limiting dilution method in transplantation to lethally irradiated mice. 7 to 12.7 HRU were found in 10(6) bone marrow cells of CBF1 mice and 19.

[The development of the hemopoietic system: colony-forming splenic units in mouse embryogenesis].

Localization and time of appearance as well as dynamics of quantitative changes of splenic colony-forming units (CFU-S) in mouse (C57BL/6 X CBA)F1 embryos were studied. Cells taken from the whole embryo (day 8), yolk sac and embryo per se (day 9), and also liver (day 10) were injected into the lethally irradiated syngenic mice. 7-8 days after the injection the spleens were fixed and the number of macrocolonies was counted.

[Induced hematopoietic foci in mice. I. Induction of extraskeletal hematopoietic areas using demineralized tooth matrix].

Conditions of formation of induced osteo-hemopoietic foci in mice, in response to ectopic implantation to them of homologous demineralized tooth matrix, have been studied. It is shown that the hemopoietic tissue of the induced foci is similar to the bone marrow of the skeletal bones by the morphological parameters and cellular composition; differentiation of precursor cells takes place in all three directions of myelopoiesis. Induced foci formation under the capsule of the kidney occurs much later (after 5-8 months) than under the skin of muscular fascia (1-1.

[Semisyngeneic transplantation of hematopoietic cells of native and cultured embryonic liver].

The protective ability and graft-versus-host (GVH) activity in parental strain hematopoietic fetal liver cells (FLC) transplanted to irradiated F1 hybrids were evaluated quantitatively. A 21-day survival of more than 80% of semi-syngeneic mouse recipients required the injection of 2-5 X 10(6) nucleated fetal liver cells (FLC). The same effect could be obtained with FLC cultivated for 4-15 days.

[Quantitative analysis of survival during syngeneic and semisyngeneic bone marrow transplantation: relation of the protective effect and the ability to induce secondary disease as affected by differences in the major histocompatibility locus].

The protective effect of bone marrow (BM) with both syngeneic and semisyngeneic transplantation is an exponential function of the number of transplanted cells. The regression coefficient in the logarithmic equation represents a fraction of hemopoiesis repair units (HRU). The quantitative analysis of the remote death of recipients of the parents' BM shows that the secondary disease (SD) is caused by other than HRU cells which is in agreement with the data obtained by other methods.

[Effect of colony-stimulating activity on hematopoiesis in the organ culture of mouse embryonal liver].

The effect of the colony-stimulating activity (CSA) on hemopoiesis in a long-term culture (4.5 week) of mouse embryonal liver was studied. After addition of the spleen cell-conditioned medium containing CSA to the organ culture, there was a decrease in the number of CFUs and in the granulocyte and macrophage precursors.

[Differentiation of erythroid progenitors in organ cultures of mouse embryonal liver].

To study the reasons for the failure of erythroid differentiation in a long-term organ culture of mouse embryonal liver, the development of erythroid colony-forming progenitors was examined. The "early" (BFUei) and "late" (CFUei) erythropoietin-independent erythroid progenitors were present in washes from organ cultures for at least 56 days and in the "rests" of the cultures for 46 days. The mean concentration and the correlation of the "early" and "late" progenitors were similar to those in the bone marrow and initial embryonal liver.

[Proliferative activity of hematopoietic stem cells in long-term organotypic cultures of embryonic mouse liver].

The proliferation of CFUs as measured by the 3H-thymidine inactivation test in organ cultures of mouse embryonic liver is maintained for 3-4 weeks. As regards the proliferation rate, CFUs located in the upper washed layers differ from those located in the deep culture layers. CFUs from washings manifested significant proliferation only in individual experiments and in the early times (3-9 days), while in the rest cases it remained at the zero level or was insignificant.

[In vitro production of hemopoietic stem cells: washings from organ cultures of embryonic liver].

Hemopoietic cells including CFUs could be washed off from the organ culture of fetal liver periodically for 4 weeks. Under the cultivation conditions employed this treatment did not reduce the CFUs content of the culture essentially; thus, the washings off could be used to elevate the CFUs yield per culture.

[Blast transformation of the lymphocytes of the blood of Macaca rhesus in culture by means of stimulation with phytohemagglutinin and allogenic leukocytes (methods of cultivation and quantitative evaluation of blast transformation)].

The authors consider a number of methodical questions of great significance for the brief-term cultures of both human and animal lymphocytes. A method of assessment of blast transformation of lymphocytes by radiometric measurement of H-3-thymidine incorporated into the cells was elaborated. A heterogenic system trichloracetic acid-insoluble cell fraction on a millipore filter--was used for measuring the tritium irradiation.