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Biomedical subjects

V N Shvets

Publications and source records attributed to V N Shvets.

At least 37 records · Page 2Linked to original sources
PubMed1979

[Hematopoietic organs in mice following a single administration of hydrocortisone].

Kinetics of the number and direction of CFU differentiating in mice after a single infusion of hydrocortisone in a dose of 5 mg per mouse was studied using the method of an exogenous cloning of the stem cells in the spleen and the bone marrow of the irradiated recipients. Against the background of the long-term involution of the thymicolymphoid apparatus a change of the number and direction of the CFU differentiating occurred. Along with this, CFU concentration in the spleen and bone marrow of mice remained constant. Under the hormone action CFU differentiating capacity in the spleen and bone marrow in the direction of erythro- and myelopoiesis sharply changes; CFU of the bone marrow behaves as CFU of the spleen, and CFU of the spleen behaves as CFU of the bone marrow of normal mice. It is suggested that the described effects of the CFU of the spleen and bone marrow of mice given hydrocortisone were due to the redistribution of T-lymphocytes and not to direct cytotoxic effect of hydrocortisone on the CFU population.

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PubMed1978

[Determination of "settling factor" (f) by the hematopoietic stem cell cloning test in mouse spleen and bone marrow].

The effect of distribution of injected colony-forming units (CFU) in the recipient's organism was studied. The distribution was assessed by the "sedimentation factor" (f) criterion. This factor was found by the number of colonies revealed on histological sections of the spleen and femoral bone marrow in comparison with the number of colonies visible on the surface of the spleen. Macroscopic count of the colonies on the spleen permits, to assess the f value both in the whole spleen volume and in the femoral bone marrow. In this case f value was independent of the character of CFU differentiation. f value could change depending on the physiological condition of CFU population. In irradiation of the bone marrow CFU in a dose of 200, 400 and 600 R f value in the spleen decreased in comparison with control, but remained unchanged in the bone marrow.

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PubMed1977

Discussion of the combined effect of weightlessness and ionizing radiation on the mammalian body: morphological data.

The combined effect of weightlessness and ionizing radiation, from the Cs137 source at 800 rads for 24 h, on the animal body was studied. The morphological examination of organs and tissues of rats flown aboard the biosatellite Cosmos-690, kept in the ground-based simulation experiment, and kept in the vivarium, indicated prevalence of radiation-induced changes in both experimental groups of rats. An exposure of animals to space flight factors did not produce a substantial aggravation of radiation-induced effects. This is indicated by the lack of significant differences in the weight of testes, thymus, and spleen of flight and simulation rats. However, this exposure affected adversely the development of reparative processes in the hemopoietic tissue of bone marrow. Inflight irradiation aggravated weightlessness-induced changes. A combined effect of weightlessness and irradiation did not result in the summation of the effects exerted on skeletal muscles by either factor alone.

Animals↗
PubMed1976

[The radiosensitivity and direction of differentiation of splenic colony forming cells].

Radiosensitivity of spleen CFU localized in the bone marrow and in the spleen proved to be the same. Do is about 105--120r for the CFU-forming colonies in the spleen and 120--135r for the CFU-forming colonies in the bone marrow. As suggested, there are two CFU fractions in the bone marrow. One of them is radiosensitive and another--radio-resistant. Chiefly the radiosensitive CFU fraction is the one localized in the spleen.

Animals↗
PubMed1976

[Effect of thymus cells on the radiosensitivity and differentiation trends of hematopoietic stem cells].

A stimulating influence of thymus cells on the capability of irradiated (from 100 to 500 r) bone marrow of mice of producing colonies in spleen of syngenous recipient has been proven. The intensification of colony formation involves an increased radioresistance of stem cells. It is supposed that radioresistant thymus cells have a stimulating effect. Thymus cells exert their influence not only to the rate of survival of stem cells proliferating in the bone marrow of femur, but also increase their erythropoetic potention.

Animals↗
PubMed1976

[Proliferation and differentiation of hematopoietic stem cells in hypokinesia].

Using the method of exogenous cloning in vivo of the hemopoietic stem cells of the bone marrow and spleen in the femur and the spleen of mice it was shown that during hypokinesia the kinetics of the stem cells differed in both organs (the spleen and the bone marrow). Differentiation of transplanted stem cells from different sources was unchanged in the spleen, but stem cells of the bone marrow seeding in the femur changed the character of their differentiation in the direction of increase of the erythopoietic function, whereas stem cells of the spleen failed to alter the direction of differentiation.

Animals↗
PubMed1976

[Distribution of colony-forming cells in the bone marrow and spleen of irradiated mice].

Two hours after the transplantation of 2-10(5) bone marrow cells 1.7--2.8% of the colony-forming units (CFU) persisted in the bone marrow and 14--16% -- in the spleen of the recipients. In 24 hours there was 1--2% of the CFU in the bone marrow and 21--26% in the spleen. The "F-factor" for these organs was constant in the recipients (under conditions of saturation) for 24 hours after the transplantation of 2.5.10(6)--1.7--10(7) bone marrow cells. The "F-factor" for the CFU seeding the spleen was 20--22% and for the CFU seeding in the femus--2,4--2,7%. It is supposed that the count of the CFU seeded in the total bone marrow volume was equal to that in the spleen. The average sum of the CFU seeding in the spleen and in the total bone marrow volume was about 40--50%. The fate of other CFU is unknown.

Animals↗
PubMed1976

Space flight effects on the hemopoietic function of bone marrow of the rat.

The 22-d orbital flight of rats onboard the Cosmos-605 biosatellite was followed by inhibition of erythroblastosis, alteration in the morphology of megakaryocytes, and stimulation of myelopoiesis. These changes returned to normal 27 d postflight. The colony-forming capacity and pattern of differentiation of hemopoietic stem cells of bone marrow of flight rats remained undisturbed.

Animals↗
PubMed1976

[Hematopoietic functions in hypokinesia].

Materials on the state of hemopoietic organs and peripheral blood of mice and rats kept under hypokinetic conditions for from 1 to 60 days are presented. The changes occurring in the lymphoid tissue (involution of thymo-lymphatic apparatus, lymphopenia and neutrophilosis) have been shown to result from the state of stress. In the bone marrow of animals there occurs activation of erythropoiesis (erythroblasts-polychromatophilic normoblasts) at early (up to 15 days) term of hypokinesia, followed by its inhibition on the 60th day of the experiment. The study of kinetics of the amount of hemopoietic stem cells in the spleen and bone marrow of the femur of mice kept under hypokinesia for 1-45 days suggests the amount of stem cells in the spleen to decrease exponentially while in the bone marrow it changes undulatorily with the maximum on the 1st-3d and 30th-45th days of hypokinesia. Shifts in the number of the stem cell population are accompanied by changes in the direction of their differentiation. The stem cells of the bone marrow manifest higher potencies to form colonies of the erythroid type as compared with the stem cells of intact animals. Possible mechanisms underlying the inhibition of lymph-and erythropoiesis and changes of the stem cell differentiation from the myeloid way to the erythroid way under conditions of hypokinesia are discussed.

Animals↗
PubMed1975

[Cloning stem cells in the bone marrow of irradiated mice].

Different amount of intact or irradiated bone marrow from syngenous donors was administered to mice irradiated with a lethal dose. There was revealed a linear dependence of the number of the 8-9-day colonies grown in the bone marrow of the femur on the amount of the administered cells, and an exponential dependence on the irradiation dose. Regularity of the stem cell cloning in the bone marrow was analogous to such in the spleen. Radiosensitivity of the colony-forming units (CFU) differed depending on the site (the spleen, the bone marrow) of their colony formation. The CFU settling in the marrow proved to be more radioresistant (D(0) equalled 160-200 P) in comparison with the CFU settling in the spleen (D(0) constituted 80-100 P). It is supposed that a different radiosensitivity of the CFU was caused by the presence of heterogenic population of the stem cells and also by specific peculiarities of the organ (the spleen, the bone marrow) in which the colonies formed.

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