The authors discuss the existence of polypotent hemopoietic stem cells in the peripheral blood as well as a possibility of restoring hemopoiesis by means of the given cells after the lethal myelotoxic exposure. In 5 patients with hemoblastoses, suspension of mononuclear leukocytes in an amount of 0.5 X 10(9) per kg bw was obtained using short-interval leukocytapheresis on blood cell separator. After carrying out different schemes of pretransplantation preparation the defrosted suspension of mononuclear cells was injected without wash out to the patients' central vein. The recovery of the peripheral blood indicators was attained on days 10-30 after the autotransplantation of stem blood cells.

Differentiation of the F9 cell line was induced by treating the cells with retinoic acid (10(-6) M) and dibutyryl cycloadenosinemonophosphate (10(-4) M). The population doubling time and the portion of cells in G1-phase increase and saturation density falls as the result of this treatment. Differentiated F9 cells demonstrate a decreased capacity of forming colonies in the soft agar, lose their capacity of proliferating at the clonal density, and acquire the limited life-span in culture after reseeding at a high density. Some cells in the differentiated population retain their capacity of forming colonies in the soft agar and (or) of binding antibodies against the stem cell marker SSEA-1. Cells with the stem cell morphology were found in the course of passaging of differentiated cells after reseeding at a high density. These cells were able to differentiate after the standard procedure of the induction of differentiation with retinoic acid and dibutyryl cAMP. Causes of the rising and supporting of heterogeneity of the differentiated F9 cells are discussed.

The authors evaluate a method of procuring and preserving fetal liver cells in a medium containing low-molecular polyvynilpyrrolidon, glucose, lactose, sodium phosphate and sodiumhydrocitrate not requiring washing off. The biomaterial is stored at a temperature of -196 degrees C. The efficiency of this method of cryopreservation of fetal liver cell suspensions was confirmed by high morphological intactness, functional activity and proliferative capacity. Patients with hypoplastic anemia subjected to transfusion of cryopreserved fetal liver cells showed a normalization of bone marrow hemopoiesis, remissions.

The structure of perinucleolar zone in nuclei of peripheral blood hemopoietic cells has been studied. The cells of human patient with chronic lympholeukemia, chronic myeloleukemia, various forms of acute leucosis have been investigated. The phenomenon of radial strings and border structures has been found in these cells. The features have been revealed by visualization of ribonucleoproteides and lipoproteins. The same process takes place in human lymphocytes after 6-24 h of 3-phosphoglyceric aldehyde stimulation in vitro. A comparative study of morphologic peculiarities of hemopoietic cell nucleolar apparatus depending on cell cycle phase has been performed. The action of cytostatics upon the structure of nucleus perinucleolar zone has been investigated.

Colony-forming fibroblast precursors were detected in circulating blood of adult guinea pigs by CFUf in vitro colony assay. SFU amount to 0.9 +/- 0.2 (M +/- m) per 10(5) explanted leucocytes ranging from 0.04 X 10(-5) to 3.0 X 10(-5) for individual donors. The presence of collagen type I and lack of factor VIII antigen and of FC-receptors proved that CFU-derived colonies in the blood cultures were composed of fibroblasts.

The role of thymus in the regulation of stromal elements, responsible for haemopoiesis inducing microsurrounding transfer of animals, subjected to 10-hours immobilization, was studied. The development of bone marrow hyperplasia and stimulation of functional activity of stromal cells, responsible for haemopoiesis inducing microsurrounding transfer, were shown to be thymus dependent processes during stress.

The techniques of cell electrophoresis and electro-orientation spectroscopy were used to study the effect of sodium dodecyl sulfate (SDS) and cetyl trimethyl ammonium bromide (CTAB) on Escherichia coli K-12 cells from the culture at the exponential and stationary growth phases. SDS (2 x 10(-4) M) considerably damaged cells at the exponential phase, particularly at pH less than 6.0, whereas cells at the stationary phase were damaged to a less degree and only at pH less than 5.3 or after their treatment with Trilon B. The damaging effect of SDS decreased in an isotonic medium (0.25 M sucrose) as compared to a hypotonic medium (distilled water). CTAB also damaged cells at the exponential phase more than those at the stationary phase, and its damaging action decreased with pH. Mg2+, Ca2+, and Sr2+ cations diminished the degree of cell damage with CTAB, but did not exert any noticeable protection in the case of SDS. The different sensitivity of cells at the exponential and stationary growth phases may be associated with changes in their surface electric charge and with the existence of hydrophobic regions on the cell surface. The higher electric charge of cells at the stationary growth phase is presumed to stem from a rise in the amount of surface lipopolysaccharides which bear a negative electric charge.

Models of endo- and exogenous clone formation were used to study colony formation in (CBA X C57B1)F1 mice in different periods after damage to the hypothalamic structures. The following dynamics of colony formation was revealed in the animals with hypothalamic damage in endogenous clone formation: intensified colony formation occurring 24 hours after injury to the brain structures was replaced by a tendency to decrease in 4 days, which was followed by marked inhibition of colony formation 8 days after injury to the hypothalamic structures. The effect of inhibition of colony formation was encountered in animals with damage to the posterior hypothalamic field. No essential changes were revealed in colony formation 4 and 8 hours after hypothalamic injury in exogenous clone formation. Comparison of the results of endo- and exogenous clone formation suggests that the inhibition of colony formation in late-term periods after injury to the posterior hypothalamic field may be due to inhibition of the migration of hematopoietic stem cells from the bone marrow.

Cells and chromosomes of the embryo can be labeled by integrating foreign DNA into its genome. Genes coding for some cytotoxic products can selectively destroy embryonic rudiments in which these genes are expressed. Insertional mutations arise in transgenic animals and this facilitates identification and cloning of the genes that affect the development. Embryos carrying mutations in certain genes were produced using transformed stem cells. Some kinds of mutations can be corrected by introducing the cloned genes into mutant oocytes. Use of transgenic animals substantially increases the properties of methods employed in developmental genetics and experimental embryology of mammals.

By means of estrogenic myelofibrosis, using the method of heterotopic transplantation of the bone marrow, interrelations of osteogenic and hemopoietic tissues have been studied. Under estrone effect disorders in stromal microenvironment take place at the level of stem osteogenic cells of the bone marrow. Deficiency in cells of monocytic-macrophagal line, inhibiting proliferation of the bone marrow connective tissue cells, contributes to development of myelofibrosis. The hormone acts mainly in committed hemopoietic cells, singly launching them from G0- into S-period of the cycle, and then--into differentiation, accompanied with an enhanced discharge of cells from the bone marrow. There is neither direct, nor indirect dependence between the osteogenic mass and the cellularity of the hemopoietic tissue of the bone marrow. The changes, that take place in the bone marrow under estrone effect, are reversible.

The system of stromal cell precursors--colony-forming units of fibroblasts (CFUf) of the bone marrow possesses a significant reserve population which is mobilized in exposure to extreme effects, after irradiation in the given case. This compensatory-adaptational reaction is evidently one of the factors of optimization of postradiation hematopoiesis restoration. Analysis of the cell composition of the CFUf reserve population showed that it does not differ basically from the population tested under normal conditions. Differences are also noted, however: two CFUf pools are distinguished in the reserve population distinctly which possess the largest cell reserve--in the region of the small and large clones.

On the basis of the analysis of postirradiation changes in the specific number human peripheral blood neutrophils the authors have estimated the level of the "arrest of differentiation" (AD) of their precursors (haemopoietic stem cells (HSC) which amounted to 0.2-0.9% of their normal number at a local functional site of haemopoiesis. The time of the onset of AD, with subcritical doses (to 6.4-8.8 Gy) leading to HSC pool depletion, which does not reach a critical level, decreases linearly with dose, and its duration is practically independent of the dose and makes up 10 (6 to 16) days on an average.

Mathematical modelling used in analysing the postirradiation changes in megakaryocytopoiesis permitted to determine the level of radiation-induced injury in each experiment conducted and to show that megakaryocytopoiesis regulation followed the same mechanism after irradiation as it does normally and after the effect of hydroxyurea and anti-thrombocyte serum. The analysis has demonstrated that after the stem cell death induced by ionizing radiation, the regeneration can be provided by the committed cells, and the level of regeneration is determined by the maturity of precursors.

Preirradiation of mouse recipients with a dose of 1-2 Gy 24 and 48 h before lethal irradiation (8 Gy) made CFUs content of femur increase upon transplantation of bone marrow from exposed and intact donors. The same was with the long-term bone marrow culture: preirradiation of a stromal sublayer increased the number of CFUs in the transplanted bone marrow preirradiated with 6 Gy radiation. Retransplantation of bone marrow to irradiated donors after 5 day cultivation, a sublayer being activated, increased the number of CFUs in the femur in comparison with donors which were injected with the bone marrow from the culture without activation of the sublayer by low-level radiation.

It is shown that immobilization stress intensifies functional activity of hematopoietic precursor cells, which leads to the development of medullary hyperplasia. Injection of dalargin into immobilized animals as well as its addition to the culture medium in producing clones of myelokaryocytes derived from donors subjected to stress in vitro reduces the colony- and cluster-forming activity of bone marrow cells and causes suppression of erythro- and granulocytopoiesis. Naloxone abolishes the suppressive effect of dalargin in vivo and in vitro but at the same time attenuates bone marrow hyperplasia in stress. It is suggested that naloxone may block both the stimulating and the inhibiting effect of enkephalins on hematopoiesis in stress.

Using the alkaline dissociation technique in the ciliary-iris complex of chick embryos 5-19 days of development by mean of 3H-thymidine and 3H-leucine radiography, qualitative cytochemistry and morphometry methods morpho-functional parameters of cell and simplast development in the myoneural tissue have been studied. As a result of divergent differentiation of the stem cells two differons are formed in the myoneural tissue: cellular and simplastic. They both interact in composition of the muscle fiber. The proliferation is specific for the cellular differon, and synthesis of specific proteins takes place in the simplasts. The proliferation and differentiation in the avian myoneural tissue occur on the base of competitive+ type of metabolism, while in the iris pigmentocytes--on the base of non-competitive++ interaction of DNA and specific protein synthesis. A conclusion is made concerning common mechanisms of development for the skeletal muscle and myoneural tissues. They are based on the single type of interaction of proliferation and differentiation processes in histogenesis of the two tissues.

An absolute number of the primitive stem cells (PSC) providing for prolonged maintenance of hemopoiesis in culture was measured with the aid of the limiting dilution method. The number of the PSC was determined according to the magnitude of the "zero" class cultures, i. e. of the cultures in which CFUs could not be demonstrated after 5-8 weeks. The fitness of the method can be proved by the presence of the linear relations between the number of the explanted stem cells and the number of the PSC as well as by the passage of the regression curve through the origin of coordinates. The data on the content of the PSC functioning in vivo and in vitro turned out similar, amounting to about 100 cells per mouse femur.