The radiotherapeutic effect of thymogen (Glu-Trp) and thymohexin (Arg-Lys-Asp-Val-Tyr-Arg) synthetic peptide immunomodulators was investigated. Both thymogen and thymohexin were demonstrated to be able to reduce the damaging effect of ionizing radiation (1 Gy) on CFU-S by half. The treatment by these preparations after irradiation at dose of 4 Gy leads to more intensive restoration of CFU-S population as compared with control.

The resistance of intercellular gaps between the blastomeres and the potential of the blastocoel cavity in the cleaving frog eggs were estimated by means of microelectrode technique. The maximal and minimal values of these parameters were evaluated in different phases of the mitotic cycle.

The status of canine hemopoietic and stromal progenitor cells in regeneration of bone tissue was studied in distraction osteosynthesis, by using the bone marrow culture technique in the diffusion chambers. Normal osteogenesis was demonstrated to be characterized by certain phase changes in the cloning of progenitor cells of myelopoiesis, whereas abnormal osteogenesis, the activity of hemopoietic cells remained virtually unchanged, but the cloning of CFU-F increased in intact bones.

Whether accessory T cells can be replaced by the synthetic immunomodulators thymogen (Glu-Trp) and thymohexin (Arg-Lys-Asp-Val-Tyr-Arg) was studied. The latter immunomodulator was found to show a 3-fold increase in splenic colony formation after incubation of bone marrow cells with rabbit antimouse brain serum (RAMBS). The former preparation failed to show the same action. Its effect was close to that of thymocytes. When the recipients exposed to lethal irradiation were administered the RAMBS-treated bone marrow cells and one of the peptides, it was shown that in concomitant administration, thymohexin and thymocytes lost their ability to restore colony formation by RAMBS-treated bone marrow. Thymogen did not suppress the stimulating activity of thymocytes. It is suggested that the differences observed between the tested peptides in their ability to recover colony formation were determined by their structure.

C57BL mice were adapted to moderate periodic hypoxia and repeated electric pain stresses of limited intensity. These animals adapted to each of the factors and control animals were given the potent mutagen, free radical oxidation activator dioxidine in a single dose of 300 mg/kg. Dioxidine administered to unadapted animals resulted in chromosomal aberrations in 11% of stem bone marrow cells mainly due to the appearance of single and multiple chromosomes. Preadaptation to stress decreased the number of these dioxidine-induced chromosomal aberrations nearly twice. Adaptation to periodic hypoxia had no defensive action. As previously shown, adaptation to repeated stresses leads to the accumulation of heat-shock proteins (HSP) in the cellular nuclei of animals and prevents the degradation of isolated nuclei when single-chain DNA is added. Adaptation to hypoxia does not cause nuclear accumulation of HSP or prevents their degradation when unicellular DNA is supplemented. This suggests that the antimutagenic effect of stress adaptation is likely to be accounted for by the stabilizing action of HSP.

A comparative study of the incidence of genetic damages induced in mouse male germ cells by a single injection of 137Cs and external gamma-irradiation shows that the incidence of dominant lethal mutations in the postmeiotic cells is similar with both radiation types. The frequency of reciprocal translocations in stem cell spermatogonia was considerably lower with 137Cs than with external gamma-irradiation which might be attributed to the prolonged effect of the radionuclide.

Mouse testes preheated up to 41.5 degrees C for 30 min exhibit an increased radiosensitivity of testis epithelium stem cells. High death rate is described by a shift (by approximately 4 Gy) in the "dose-response" curve to the Abscissa left. The DMF value for hyperthermia depends on the cell survival rate, at which calculations are made, and varies from 2.1 to 1.4 within the range under study.

Adaptive response of colony forming units in mice spleen (CFU-S) was investigated in exotest after preirradiation with doses of 0.3-5.0 sGy of 60Co. Adaptive radioresistance was manifested from 4 hours till 28 days after each challenge dose. Low dose rate preirradiation is less effective as adaptive response inducing action than high dose rate one.

Lethally irradiated mice were reconstituted with hematopoietic cells retrovirally marked by human ADA sequence. Before and during gene transfer adult bone marrow cells were pre-stimulated by a combination of exogenous growth factors, IL-6 and kit-ligand, or by culture on irradiated adherent cell layer of long-term bone marrow culture. Twelve-day-old embryonic liver cells were transduced without prestimulation with exogenous growth factors. In mice reconstituted with growth factors stimulated adult bone marrow cells during 4 months after transplantation 200-300 hematopoietic cell clones were functioning simultaneously. Five months and later after reconstitution oligo-monoclonal hematopoiesis was revealed. The findings suggest that growth factors induce long-lasting proliferation of quiescent pHSC as a result of which clone(s) with proliferative advantage replace all others and only this clone(s) persists during long time, up to 11 months. Vice versa, in mice reconstituted with adult or embryonic hematopoietic cells which were transduced without growth factors prestimulation, the phase of polyclonal hematopoiesis was never observed and hematopoietic cell clonal succession was revealed. The data obtained for the first time demonstrate artifactual influence of high-concentration IL-6 and kit-ligand on the developmental potential of hematopoietic stem cell. The model can be useful for the study of mechanism of hematopoiesis regulation, proliferative and developmental potential of primitive HSC and growth factors effect on them.

The pool of hematopoietic cells-precursors from the peripheral blood of patients with lung cancer stage III-IV was characterized by reduced number of circulating cells-precursors of granulomonocyto-(CFU-GM) and erythropoiesis (CFU-E). In the course of antitumor chemotherapy the counts of CFU-GM and CFU-E diminished 2 and 4-fold, respectively. The prednisolone functional test determined that depletion of CFU-GM and CFU-E pools in the peripheral blood was preceded with lowered pool reserve for hematopoietic precursors.

Effects of helium-neon and cadmium-neon lasers with wavelength 632.8 and 470 nm correspondingly with power 20 mw and also argon laser with wavelength 480 nm, power 1 w on "early" and "late" colony-forming units (CFU) of mice bone marrow were appreciated. The helium-neon laser as compared to the cadmium-neon one stimulated the "late" CFU and incorporation of 3H-thymidine in DNA of the bone marrow cells after 30 or 45 min exposition. The more powerful argon laser after 30 min exposition suppressed "early" and "late" CFU completely by 50% dead cells of the bone marrow. A decrease of the argon laser exposition to 5 min was accompanied, by the preservation of the bone marrow cells viability at the control level and ability to stimulate "early" CFU.

In experiments with mice exposed to gamma quanta (6.0 Gy) it was shown that a single injection of disodium salt of 2,4-di(alpha-methoxyethyl)deuteroporphyrin IX (50 and 12 mg/kg) both 15 min before and 15 min after irradiation promoted postirradiation regeneration of all bone marrow haemopoiesis compartments. The agent produced a more pronounced stimulatory effect when administered after irradiation.

There was a 30% increase in spermatozoids with microheads and a 3-fold increase in "young" spermatozoids at later times after irradiation of BALB/c mice a dose of 1.0 Gy. With radiation doses of 0.1-1.0 Gy, BALB/c and CBA mice (which differ in viability of spermatogenous cells, the number of Sertoli cells and total embryonal death rate) exhibited a significant increase in the preimplantation death at the stage of spermatogonia and stem cells. The results obtained indicate reduction of the fertilizing capacity of sperm which is probably realized as dominant lethal mutations.

It was shown that in vivo trecrezan possessed strong immunoactive properties: it decreased the spot-forming activity of polypotent stem blood cells, stimulated lympho- and hemopoesis, antibody formation, possessed steady antiinflammatory activity. It stimulated in vitro mononuclear cell proliferation in man due to its direct action on B lymphocytes and increase in lymphokine and monokine production.

The study was aimed at the evaluation of functional condition of pancreatic islet apparatus in patients with Cushing's disease who underwent adrenal microsurgical transplantation after bilateral adrenalectomy. The examination of 19 patients included immunological tests as well as calculation of insulin level increase, insulin ejection rate and insulin level excess over the baseline after glucose loading. The results suggest that patients with Cushing's disease in active stage reveal increased sensitivity to glucose and functional capacity of pancreatic beta-cells. After unilateral adrenalectomy insulin base level was observed to fall while increased beta-cells responsiveness to glucose remained unchanged. At the same time adrenal autotransplantation on the vascular stem in patients with the Cushing's disease resulted not only in normalization of insulin base level but also in the improvement of the functional indices of the islet cells.

The method of heterotopic transplantation of the bone marrow was used to study the influence of splenectomy and autotransplantation of the spleen onto the hemopoietic and osteogenic tissues of the bone marrow in mice. After splenectomy at early stages of the formation of the heterotopic hemopoiesis focus the amount of myelokaryocytes increased while in the stationary bone marrow population (the femur bone) their amount dropped by the same time. Autotransplantation of the spleen made the amount of myelokaryocytes equal to the level of control, but did not eliminate the effect of decrease of the mass of osteogenic tissue in the heterotopic hemopoiesis focus arising after splenectomy, which might be related with the influence of splenectomy on the stem osteogenic cells-precursors of the bone marrow.

The experiments on dogs have shown that at the moment of maximal thrombocytopenia, induced by using of 0.7 mg/kg rubomycin intravenous daily during 5 days, there was a sharp increase in cAMP concentration, while the content of prostaglandin E group and F2 alpha in blood decreased. Concentration of cGMP began to increase by the 10th day. We can arrive at the opinion that the rubomycin acts on the receptors of hemopoietic precursor cells' membrane. This causes the activation of adenylate-cyclase, which stimulates the formation of cAMP, causing cells' proliferation depression. This mechanism may be regarded as the restoration reaction of megakaryocyte-thrombocyte system.

The mechanisms of regulating influence of D-glucuronic acid on granulomonocytopoiesis++ have been studied by using the model of cyclophosphamide-induced myelodepression. Increase of colony-stimulating and interleukin-1 activities production by hemopoiesis inducing microenvironment cells, the stimulation of hemopoietic islets and the different granulomonocytopoiesis precursor cells forming have been shown to be the base of activating action of D-glucuronic acid on bone marrow granulomonocytopoiesis recovery.