A cell line similar to embryonic stem cells has been isolated from 5-day rabbit embryos. After the disruption of zona pellucida, embryos were mechanically separated into cel aggregates, which were then cultivated on a feeder layer of primary mouse embryonic fibroblasts. Cells similar to embryonic stem cells had high nuclear-to-cytoplasm ratio. It has been demonstrated for the first time that the inner cell mass and embryonic stem cells of rabbits expressed the activity of alkaline phosphatase. Between 10 and 30% of cells retained this expression and pluripotent characteristics up to the 23rd transfer. After 14-17 transfers the obtained embryonic cells could be induced to differentiation in vitro, which resulted in the formation of embryoid bodies. After the 23rd transfer, the line of rabbit embryonic cells was lost as a result of its differentiation.

In review of literature on experimental material the advantage of recombinant cytokine use is shown in acute radiation illness treatment. In review a number of tactical questions of cytokine therapy are interpreted: period and timing of medicines application, synergism and others.

Mouse embryos were analyzed vitally, on fixed total and chromosome preparation at the two-cell stage and during transition to the four-cell stage, upon polyethylene glycol-induced fusion of sister blastomeres and early cleavage of thus obtained somatic hybrids. Vital staining by Rhodamine 123 showed a diffuse distribution of functionally active mitochondria with a decreasing gradient towards the periphery of blastomeres, concentration in the zone of contact between the blastomeres, and as a ring in the center. A weakly fluorescent zone inside the mitochondrial "ring" corresponded to the interphase nucleus position, as followed from vital staining by Hoechst 33258 and analysis of fixed embryos stained by lacmoid. In the course of cleavage, the mitochondria aggregated in the zone of condensed chromosomes. The topography of mitochondria reflected the barrel shape of the spindle division similar in the intact blastomeres and products of fusion and allowed us to follow segregation of the cytoplasmic and nuclear materials among the daughter cells until the mitosis completion. During formation of the fusion products, the preserved cytoplasmic boundary was visualized by the location of mitochondria, thus suggesting the absence of intense changes in the cytoplasm during fusion of the blastomeres. The movement of mitochondrial "rings" marked the centripetal translocation of the nuclei. We did not observe formation of a common "ring" or fusion of the interphase nuclei. Association of the nuclear materials took place only at the metaphase stage. Sister blastomeres of the two-cell somatic hybrids, just as those of intact embryos, entered the subsequent cleavage division asynchronously. Cytogenetic analysis confirms formation of the tetraploid embryos as a result of induced fusion of sister blastomeres.

Hemopoiesis and functional activity of monocytes were assessed in 30 patients with chronic myelomonocytic leukemia (CMML). Changes in haemogram in CMML are characterized by anemia, thrombocytopenia, normal or increased count of leukocytes with absolute monocytosis and increased count of young granulocytes. Bone marrow hemopoiesis is characterized by enhanced proliferation of cellular elements of granulocytopoiesis and monocytes, suppressed erythropoiesis and megakaryocytopoiesis. Dysplastic changes are most expressed in the erythrocytic stem cells. Studies of lysosomal enzymes showed their increased activity in monocytes of CMML patients.

Bone marrow hemopoiesis, a state of the committed precursor cell pool and the nature of their interaction with hemopoiesis-inducing microenvironment (HIM) elements, the level of humoral stimulants of secretion, was studied following a single injection of 5-fluorouracil (5-FU), cyclophosphamide (CF) or adriamycin (A) to mice in maximum tolerance doses. Cytostatic-related changes in hemopoietic recovery were shown to depend primarily on the proliferation-differentiation relationships in the hemopoietic cells, which is in its turn determined by the status of HIM cells after cytostatic exposure. The enhanced functional activity of HIM elements in response to hemopoietic tissue damage induced by A or CF promotes rapid hemopoietic recovery which becomes much more accelerated while using recombinant colony-stimulating factor (CSF) and, to a lesser degree, glycyrrham, a plant drug. At the same time 5-FU that caused prolonged bone marrow hypoplasia impaired the function of microenvironment cells. The use of this model demonstrated a lower efficiency of CSF than glycyrrham that normalized the structure of HIM.

High-dose chemotherapy using transplantation of hemopoietic precursor cells offers much advantage for treatment of prognostically unfavorable cancers of the breast. Both experimental and clinical evidence points to a potential of raising antitumor effect by increased dosage of chemical drugs. Clinical studies using high-dose chemotherapy for treating patients with stage II-III tumors or with greater than or equal to 10 positive axillary lymph nodes, and locally-advanced and disseminated tumor established a relative rise in overall and recurrence-free survival, as compared with standard treatment. Hazardous cytopenia and related complications can be significantly reduced when hemopoietic precursor cells are transplanted from peripheral blood.

It was found out, that immunomodulative action of low frequency acoustic oscillations (LFAO) is mediated in mice by enhancement or decreasing of distinct stages of immunogenesis. Exposure to this factor at intensity of 80 dB varied number of cells in lymphoid organs, enhanced cell proliferation, improved cooperative interaction of thymocytes and bone marrow cells in immune response, caused increase of allogenic stem cells inactivation. On the contrary, exposure to LFAO at the acoustic pressure of 130 dB caused alternative effects, as inhibition of immunocompetent cells in interaction.

Analysis of transplantations of allogenic bone marrow (BM) for determination of transfusiological problems arising in various types of donor's and recipient's blood ABO incompatibility.

Evaluation of efficiency of bone marrow and peripheral stem cells transplantation in patients with solid tumors.

To elucidate prognostic value of MDR-1 gene expression in patients with chronic myeloid leukemia (CML).

Internittent hypoxic training (IHT) increased the quantity and secretory activity of peptidergic neurons of the paraventricular hypothalamic nucleus (PHN) and activated neurons of the dorsal motor nucleus of n.vagus. These structures seem to take part in realisation of the IHT activating effect on condition of the pancreatic delta-cells. The effect involves insulin-stimulating and insuloprotective effects realised via hypothalamic and neuro-conducting ways of regulation of the endocrine pancreas with a direct participation of hypothalamic neuropeptides.

The investigation was concerned with the effect of magnetic field on the colony- and cluster-forming potential of myelo- and monocytopoietic precursor-cells in different blood diseases. Bone marrow from 72 patients was exposed in vitro to low continuous magnetic field and to intermittent continuous and pulsed one--from another 22 patients. The ADMT-Magnipulse source was used. Magnetic field proved a biologically-active factor capable of changing the clone-forming properties, proliferative and, possibly, differentiating potential of hemopoietic precursor-cells.

In the present paper we have shown that JB6 and PDV murine skin carcinoma cells, as well as previously described sarcoma B6-4 cells, can revert to a nontumor phenotype. Revertant carcinoma clones could not grow in soft agar conditions and like sarcoma revertants acquired dependence on peptide growth factors, and exhibited a reduced expression of c-jun. Spontaneous revertants were shown to be instable. They could revert back to a transformed phenotype in 1-5 months of in vitro passaging. Being inoculated in syngeneic animals, these transformed cells show a recurrence in 2-5 months, similar to that of a dormant metastasis. Thus, dormant revertant cells are believed to be included in many tumors of different origin. So, spontaneous reversions of tumor cells may play an important role in the dormant metastatic process. The cause of these frequent spontaneous transient reversions and revertant instability appears to be of epigenetic nature. Causes and mechanisms of cell transformations and reversions remain to be clarified.

On the model of experimental acute anaemia of rats, induced by injection of phenilhydrazine, the influence of calcium precipitate of double-stranded RNA (Ca-ds-RNA), introduced during the crise of anaemia, on the process of erythron restoration, was studied. In the presence of Ca-ds-RNA the number of pro- and erythroblasts in fission increases by 1.5 times, compared with "pure" anaemia situation, and accordingly there is a marked decrease in the share of microcytes, which play an important role in the restoration of cell number, and in the erythron recovery after the crise of anaemia. Less pronounced is the influence of Ca-ds-RNA on the macrocytosis, which keeps its value in spite of the increase in the speed of development and of the number of normocytes after Ca-ds-RNA introduction. The mechanism of Ca-ds-RNA inclusion in the system, which controls the process of erythropoiesis during anaemia, is discussed. A conclusion is drawn that Ca-ds-RNA may directly affect the inductive stage of erythropoiesis, stimulating the formation of competent erythroid cells in population of stem haemopoiethic cells and their proliferation. Further development of bone marrow cells takes place according to the known programme of erythropoiesis whose variations are stimulated by the current conditions of its realization, but not by the presence of Ca-ds-RNA.