Histofluorescence technique using glyoxylic acid revealed a specific fluorescence suggesting the presence of biogenic monoamines in early developmental stages of CBA x C57 Black mice. A yellow fluorescence observed in the blastomere surface from the stage of zygote up to that of four blastomere points to the presence of indole derivates. As development proceeds, the fluorescence increases and its colour becomes more and more green, which is characteristic of catecholamines. From the stage of eight blastomeres up to stage of blastocyst specific fluorescence is revealed in the cytoplasm. The inhibitors of monoamine oxidase, introduced into pregnant mice, markedly increased the specific fluorescence. An assumption is made of functional activity of biogenic monoamines in early mouse embryos.

To isolate peripheral blood stem cells, a fraction of the mononuclear blood cell suspension, 51 leukapheresis procedures were conducted in 8 patients with hemoblastosis using the continuous-flow blood cell separator Fenwal CS-3000. The blood volume processed in a procedure was 10 l at a flow rate of 40-60 ml/min, the centrifuge speed was 1600 rpm. The standard computer program of the Separator was modified depending on the whole blood rate and the patient's hematocrit. The mean yield of mononuclear cells per run was 6.3 X 10(9). Leukapheresis has not significantly affected the patient's blood cell concentration. The mean content of granulocytes in the leucocyte suspension comprised 1.89%. No complications or side effects were observed in the patients during leukapheresis procedures.

The number of spleen colonies produced by fetal liver cells of different gestational ages were compared after injection of the thymus cells into the irradiated recipients. It has been shown that thymocytes that lack influence on spleen colony formation by normal born marrow can increase the number of spleen colonies formed by 12-16 day fetal liver CFU-S. It can be concluded that the population of accessory T cells which have a role in spleen colony formation have been formed to the end of pregnancy.

Cell composition of erythroblastic islands (EI), normal and at the phase of stimulation and inhibition of erythropoiesis at modelling of heat adaptation has been studied on hemopoietic tissue of 108 rats. In the hemopoietic tissue, together with EI of the 1st, 2nd and 3d classes of maturity, that have in their composition correspondingly up to 8, from 9 up to 16 and above 16 nuclei-containing erythroid cells, there are involutive and reconstructing EI. The involutive EI are presented as nuclei-containing erythroid cells, that are not able to divide and are at late stages of differentiation: polychromatophilic and oxyphilic normoblasts, as well as reticulocytes. The reconstructing EI have in their composition both erythroid cells, that are not able to divide, and erythroid cells (pro-, erythroblasts and basophilic normoblasts), that are at early stages of differentiation. Application of the EI classification suggested, takes into account the rate, with which the erythroid cell-predecessors are drawn into erythropoiesis and intensity of erythroid differentiation. Therefore, it is possible to obtain earlier and more exact data on the state of hemopoiesis in comparison with traditional hematological methods.

In studying the influence of cystamine and gammaphos on the recovery of mouse jejunum epithelium after irradiation with doses inducing intestinal form of acute radiation sickness, it was shown that the radioprotective agents did not influence D0 value for intestinal epithelium stem cells, but in crypts the number of DNA-synthesizing enterocytes that entered mitosis increased after the preventive administration of the radioprotectors. All this caused the number of cells per villus to increase and intestinal mucosa to recover more readily.

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. Statistically significant number of CFU-S was detected starting from day 10 of development, first in the embryo (30-33 somites), then in yolk sac and blood (37-38 somites) and liver (after the 40 somites stage). Rapid increase of CFU-S number during days 11-12 (two-fold increase in about 4.6 hours) suggest that not only active proliferation of CFU-S but also maturation of CFU-S precursors take place.

Diurnal fluctuations of endogenous RNA polymerases activity were studied in the cell nucleus of the cerebral stem and spinal nervous system populations (neurocytes of the hypothalamic suprachiasmatic nuclei, superior cervical ganglia, spinal ganglia L5, motoneurones of the spinal cord and Purkinje cells) were revealed. The acrophases of the visual cortex neurones were observed just before light reception.

The in vivo induced pCTL-2 with phenotype L3T4- Lyt2- specific to the H-2Kb molecule, turn into effector CTL during 4 days in the mixed lymphocyte culture (with heat-treated donor stimulators) much more efficiently when donor and recipient are different from one another not only in MHC class I (anti-BIO, MBR BIO.AKM) but in I + II (Kb + Ib) ahti-C57BL/6 BIAD2(RIOI). The initial pCTL-2 differentiation in enhanced as a result of synergistic effect between the Kb alloantigen and rIL2. The anti-Kb pCTL-2, being separated from helper T cells by means of absorption onto the macrophage donor monolayer and elution from it, give rise to pronounced differentiation in simplified conditions, irrespective of the stimulator presence and without external rIL2. It is supposed that these phenomena are raised to secretion of the CTL differentiation factor by the eluted pCTL-2 themselves, and besides, rIL2 may promote for secretion of this factor additionally.

Dynamics concerning certain intercellular junctions have been followed during the preimplantation period of development in mouse embryos. The morphological analysis of the preimplantational embryos has demonstrated, that at the initial stages of cleavage (2-4 blastomeres) the cells make contacts by means of nonspecific junctions. Specialized intercellular junctions appear at the stage of 8 blastomeres and are presented as dotted tight and gap junctions. When the embryo is developing from the stage of 8 up to the stage of 16 blastomeres, certain connective complexes appear, consisting of dotted or cord-like tight and gap junctions. At the late morula stage, the external blastomeres in the apical part have contacts with each other by means of cingular tight junctions. In this place a connective complex might emerge; it is displayed as a tight junction and one or two gap junctions. At the blastocyst stage desmosomes and adhision zones appear. Between trophectodermal cells a connective complex arises; it is presented in the slice as a tight cingular junction, desmosomes (as a rule two) and an adhision zone. Between cells of the internal cellular mass the intercellular junctions are presented as dotted tight and gap junctions. Cells of the polar trophoectoderm and cells of the internal cellular mass could have contacts by means of gap and dotted tight junctions.

The data obtained show that clonogenic RA-2T cells are 2-3 times more thermoresistant than clonogenic cells of the original thermosensitive RA-2T strain as estimated by D0 value upon heating up to 43-45 degrees C. After X-irradiation of rat rhabdomyosarcoma, a decrease in the capacity of forming pulmonary colonies is more pronounced in cells of the thermosensitive RA-2 strain cells than in those of the thermoresistant strain RA-2T (D0 = 1.6 Gy and D0 = 2.4 Gy, respectively). In all appearance, within one and the same tumor cell population, the hereditarily thermoresistant cells are more radioresistant than the thermosensitive ones.

In experiments with F1 (CBA X C57Bl) mice irradiated with doses of 6.5 to 8.5 Gy the evidence was obtained for the important role of the reimplanted cells in a complete realization of the reparative effect of exfusion, incubation and reimplantation of bone marrow. The increase in radiation dose was accompanied by a tendency towards the decrease in the efficacy of the procedure, and, perhaps, by changes in the ratio of roots of haemopoietic stem cell differentiation.

Some thiazole, triazole, thiadiazine, and heterylalkane derivatives increased the lifespan of gamma-irradiated (9-14 Gy) mice up to 6-22 days (as opposed to 4.1 days in the irradiated control). The efficacy of chemical agents within the dose range mentioned above was mainly associated with protecting intestinal epithelium stem cells the number of which was 4-9 times as large as that of nontreated animals. There was a moderate (40-50%) decrease in oxygen consumption under the effect of the most active radioprotectors.

The effectiveness of the enzymatic and mechanical methods for isolation of hemopoietic islets (HI) from rat bone marrow was comparatively studied. It has been shown that the use of collagenase brings higher yields of HI than the mechanical treatment of bone marrow, mainly at the expense of associations containing no central phagocytizing macrophages. When the mechanical method of HI isolation was used, erythroid islets associated with mononuclear phagocytes prevailed, while with the enzymatic method mainly erythro-granulocytic islets associated with macrophages or reticular cells were isolated. It has been suggested that granulocytic and erythro-granulocytic associations are less resistant to the mechanical treatment.

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 (1-1.5 months). The induced hemopoietic foci functioning continues at least for one year.

A new category of primitive hemopoietic stem cells determined in murine bone marrow long-term culture (CFU-BMLTC) is described. The novel precursors give rise to hemopoietic colonies corresponding to "cobble stone" areas observed on the adherent cellular layer. The linear relationship between the colony number and the dose of bone marrow cells explanted in the culture has been discovered. Radiosensitivity of the new type of hemopoietic precursors in the bone marrow of adult mice is characterized by D0-1.28 Gy. CFU-BMLTC were also identified in 13-day mouse fetal liver. In contrast to CFUs the precursors described are less sensitive to extensive in vivo treatment with hydroxyurea. The data obtained have permitted the authors to make a conclusion on a higher status of CFU-BMLTC as compared to CFUs in the hemopoietic stem cell hierarchy.

The study of precursor cells of granulocytes and macrophages has shown that in children with immune neutropenia the higher division of granulopoiesis-committed precursor cells is not affected, while the defect is localized in the periphery of hemopoiesis, and it is induced by increased destruction of neutrophils.