Anabol is a biopolymer from the complex of components extracted from the surface layer of the Lactobacillus bulgaricus cell wall. Its effect on certain indices of the functional activity of mononuclear phagocytes was studied. Administration of the preparation in a dose of 20 mg/kg 24 hours before the investigation resulted in lowering of the stain half-life in the general blood flow and increasing of the fibronectin levels in blood plasma of rats. Activation of the metabolic activity estimated by nitroblue tetrazolium test as well as resident cells and induced macrophages was observed. 24 hours after the anabol administration there was noted a marked increase in the pool of the precursors of granulocytes and macrophages, the stimulating effect being preserved for up to 3 days. The results showed that anabol had an effect on various elements of the system of mononuclear phagocytes. It may be useful in complex therapy aimed at increasing the host resistance to diverse toxic substances and bacterial infection.

Using heterotrophic transplantation of syngenic bone marrow under the renal capsule, the effect of hypokinesia on osteogenic and hemopoietic cells-precursors as well as on de novo formed bone marrow was investigated. Altogether 16 experiments were performed, employing 260 recipients and 200 donors in two modifications: 1) bone marrow from animals exposed to hypokinesia for 3 days or 3 weeks (stage I or II of the general adaptation syndrome) was implanted to intact mice; 2) recipients who 5 to 7 day before exposure were implanted with bone marrow from intact donors were hypokinetic for 3 weeks. It was found that determined bone marrow precursors of osteogenic tissue as well as cells transferring hemopoietic microenvironment remained insensitive to hypokinesia. Three-week hypokinesia produced noticeable inhibition of osteogenesis and hemopoiesis. It is concluded that the stress-reaction plays the leading role in the changes that develop in hypokinetic mice.

The effect of pathogenic and noninfectious influenza viruses with different surface antigens on colony-forming stem cells of (CBA X C57BL/6)F1 mice was studied. Bone marrow cells were infected with A/PR8/34 (H1N1)/A/Krasnodar/101/59 (H2N2) viruses, a recombinant A/PK-6-3 (H2N1) strain thereof, A/Khabarovsk/933/77 (H1N1) strain; then they were inoculated intravenously to irradiated (820 rad) syngeneic recipients, and colony-forming units (CFU) were determined in the spleens 9 days after injection. Inoculation of bone marrow cells (2 X 10(5) per mouse) to the irradiated recipients immediately after mixing with a live A/Krasnodar virus heated at 56 degrees C, live A/PK-6-3, and A/Khabarovsk viruses resulted in suppression of formation of CFU and marked atrophy of the recipients' spleens. There was no suppression after the use in these experiments of the pathogenic A/PR/8/34 strain. Inhibition of CFU production in the spleen was observed after inoculation of the recipients with bone marrow cells incubated for 1 hour at 37 degrees C with A/PR/8/34, A/Krasnodar/101/59 viruses and the recombinant strain. Possible mechanisms of the suppressive effect of influenza A virus on CFU production in mice are discussed.

Histological analysis was carried out on the hemopoietic spleen colonies within 7 and 11 days after transplantation of the embryonic liver cells. Large superficial colonies were always present and were, predominantly, erythroid and mixed. Small superficial colonies consisted of undifferentiated cells and, unlike large colonies, appeared on the 11th day only. In the spleen thickness erythroid colonies predominated. The possibility of formation of small superficial 11 day colonies at the expense of pre-CFU-S is discussed.

Mice of the strain (CBA X C57Bl) F1 injected with a single dose (40 mg.kg-1) of dextran sulphate (m.w. 5 X 10(5] were used to determine the survival rate after a lethal dose (13.0 Gy) of gamma irradiation, the number of haemopoietic stem cells in bone marrow (CFUs) and that of spleen endogenous colonies. Irradiation was performed in a hypobaric chamber at levels of 20%, 15%, 12% and 10% of the oxygen content. While in the control groups the levels of hypoxia showed a weak radioprotective effect in animals treated with DS, radioprotection was observed both in 10% O2 and in 15% O2. The animals treated exhibited a higher survival rate up to day 30 after irradiation, an elevated number of survived haemopoietic stem cells (CFUs) in the bone marrow, and increased number of endogenous spleen colonies, as compared with the control group. The potentiation of the radioprotective effect of hypoxia (10% O2) was observed till the end of observation (6th day after DS injection). The results obtained support an earlier observation that increased activity of haemopoiesis forms a convenient pool for the potentiation of the radioprotective efficiency of hypoxic hypoxia.

Restoration ability of early and late CFUs has been studied using bone marrow sublethal fractional irradiation. It has been shown that CFUs capacity for early postirradiation repair on the 11th day is sharply reduced, as compared to that of CFUs on the 8th day.

A description of the consecutive stages of ripening of ovary cells of early fission and gastrulation of T. pisiformis and T. hydatigena, peculiar to the common type of fission of Cyclophyllidea is given. The fission has signs of double spiral fission which takes place in primitive Turbellaria. The primitiveness of early embryogenesis is reflected in early determination of macromeres, in the absence of strict regulation in the location of blastomeres, in the formation of blastula and unipolar gastrulation with the absence of morphological differentiation of ectoderm and mesenchyme.

Expression of the erythroblast antigen (AG-EB) on the membrane of the mouse hemopoietic cells was studied using a FACS II flow cytofluorimeter with monoclonal antibodies MAE15. It was shown that AG-EB was present on the surface of 14% of the late committed erythroid precursors (CFU-3) and of practically all more mature erythroid cells. The role of AG-EB in maturation of the erythroid cells is discussed.

The origin of fibroblast-like cells of the capsule around a foreign body in the spleen, liver, peritoneal cavity, subcutaneous connective tissue of mice, the localization of cells-precursors, their proliferative potencies and the ability to migrate through blood were studied using 3H-thymidine autoradiography. Precursors of the inflammation focus cells (irrespective of localization) reproduce intensively outside the limits of intraorganic connective tissue, supposedly, in hemopoietic organs of the bone marrow type and migrate, through the blood channel, into tissues (inflammation foci), where they terminate their differentiation.

10 healthy men underwent a 48 hour acute hypobaric hypoxia in the "Tabaĭ" climate chamber imitating conditions of an altitude of 4.00 m. above s.l. The "ascent" and "descent" took 30 minutes each. Blood and bone marrow samples were taken before entering the chamber and immediately after leaving it. A decrease in colony-forming capacity of granulo- and monocyte and fibroblast precursors was shown, along with an increase in functional activity of circulating monocytes and monocyte precursors in bone marrow. A possible role of changes in granulo- and monocytopoiesis and in stromal cells is discussed in relation to the increased morbidity and decreased cicatricial and bone tissue reparation in the mountains.

The data of the study of alpha/beta interferon (IFN) effect in mice of different genotype were presented. CBA mice of H-2k genotype, C57B1/6 mice of H-2b genotype and their hybrid (CBA X C57B1/6) F1 have been used in the experiments. IFN has been injected intraperitoneally in a dose of 100-5000 U/mouse in combination with antigenic stimulation. It was shown that IFN enhanced stem cells migration from bone marrow in CBA, but not in (CBA X C57B1/6)F1 mice. At the same time the splenocytes from CBA mice were more sensitive to inhibition by IFN than splenocytes from C57B1/6 mice. This was found in antibody and immune rosette-formation tests. The effect of IFN on the immune system cells is probably predetermined by the individual genetic characteristics of a mouse strain.

The influence of the peritoneal cells unstimulated by an inflammatory agent (PCs) on the bone marrow erythropoiesis in the CBA mice was studied in the normal conditions and after the massive haemorrhage. The PCs obtained from the intact or anemic donors (2, 4 and 18 h after the haemorrhage) were introduced intraperitoneally into the intact syngeneic recipients. The massive haemorrhage induces a special type of differentiation of erythroid cells in bone marrow, "reserve erythropoiesis", which is characterized by a decrease, within four days, in the proliferation of basophilic proerythrocytes, stimulation of proliferation of polychromatophilic proerythrocytes and entry of oxyphilic proerythrocytes into mitosis. The transplantation of the PCs from the anemic donors induced the "reserve erythropoiesis" in the bone marrow of the recipients. The transplantation of the PCs from the intact donors did not induce the "reserve erythropoiesis" and appeared to inhibit erythropoiesis via lengthening the time of mitoses in polychromatophilic and basophilic proerythrocytes.

The administration of allogenic (CBA----C57B1/6) and semi-allogenic (CBA----F1) lymphocytes to sublethally exposed recipient mice either stimulates or inactivates endogenous colony-formation depending on the dose of lymphocytes administered. The stimulation of endogenous colony-formation correlates with the increased survival rate after radiation doses that decrease the survival rate of the control recipients.

The possibility of TPA-induced differentiation of K-562 cell line was studied. Monoclonal antibodies against differentiating antigens of HAE erythroid lineage and against myelomonocytic ICO lineage raised in the USSR Cancer Research Centre were used. Changes in immunological and cytochemical indexes suggest that K-562 cell differentiation goes in the erythroid direction. The cells lost early differentiation and acquired late differentiation markers.

The results of the cloning of fibroblastic colony-forming units (CFU-F) from the bone marrow of normal sites of the spongy bones were analysed in 250 orthopaedic patients. It has been shown that the activity of CFU-F was changing during a year. The number of negative results of CFU-F's cloning were 33%, 60% and 50% in March, April and October respectively. The absolute values of CFU-F cloning were lower in March and April than in other months. The seasonal changes in the activity of CFU-F in human bone marrow should be taken into consideration when studying the physiology and pathology of the bone and hemopoietic system, and in clinical practice.

Incubation, in various conditions, of bone-marrow samples taken from irradiated (7 Gy) (CBA X C57Bl)F1 mice and the subsequent testing thereof for stem potency in the exposed (8.5 Gy) recipients have demonstrated, with certain admissions, that stem cells can recover from radiation injury in certain experimental conditions.

A factor was discovered in the human serum, placental serum from the umbilical cord of pregnant women and sera of peripheral blood from some healthy donors, which induces one of the late stages of differentiation: switching of IgM to IgG synthesis in the RPMI-6410t line of human lymphoblastoid B-cells. Earlier we observed the induction of another stage of differentiation in the same cell line: switching of IgM to IgA synthesis under the influence of a factor from the serum of cattle foetuses. We have shown that both the stages of differentiation are induced by the above factors not only in the initial cell line but also in a number of IgM+-sublines obtained by cloning with limiting dilutions. It was, thus, established that there are factors of class-specific switching and the B-cells of a human lymphoblastoid line are capable to proceed in vitro through different stages of differentiation inherent in the B-lymphocytes in vivo.

A substance inhibiting DNA synthesis in mouse leukemic cells was isolated from the regenerating calf spleen. When added to a suspension of leukaemic cells, this substance is adsorbed on their surface. The following changes in cell features being noticed: 1) a minute decrease in electrophoretic cell motility, 2) a decrease in esterase activity of the cells, 3) an increase in microviscosity of membrane lipids, 4) an increase in the intracellular pH values. With a longer contact with this substance, changes in nuclear chromatin structure were noticed, with special reference to weakened bonds between DNA and proteins. The data obtained are of significance for revealing molecular mechanisms of hematopoietic mediator action on target cells.