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Biomedical subjects

D Rotkovská

Publications and source records attributed to D Rotkovská.

At least 19 recordsLinked to original sources
PubMed1993

Effects of microwaves on membranes of hematopoietic cells in their structural and functional organization.

The role of cell membranes in stimulating and inhibiting the effects of microwaves was investigated in experiments carried out with a suspension of murine bone marrow cells irradiated with microwaves in vitro [f = 2.45 GHz, CW, specific absorption rate (SAR) = 12 W/kg]. Results obtained by means of a structural probe, 2.4-TNS, indicate that no structural changes occur in the region of the protein-lipid interphase under conditions of short-term irradiation with microwaves that induced temperatures in the range 36-45 degrees C (exposure time 315 and 525 s, respectively). Investigation of one functional parameter--the ability to produce hematopoietic colonies in the spleen after transplantation of the bone marrow irradiated in vitro by microwaves--indicated the possibility of affecting stimulatory and inhibitory effects of microwaves by using a blocker of cell receptors, Trimepranol. The role of microwaves as a physical factor interfering in the process of cell proliferation at the level of receptor regulation is discussed.

Animals↗
PubMed1993

Evaluation of the biological effects of police radar RAMER 7F.

This paper presents results of experiments on the effects of electromagnetic radiation in the millimeter range (frequency 34.0 +/- 0.1 GHz, power density 20 muW/cm2) emitted by a police radar device. Considering the physical properties of the radiation in millimeter range (skin effects), the experiments were carried out on hairless mice. The main physiological parameters tested were body mass, body temperature, peripheral blood, and mass and cellularity of several important organs. Critical organs, the skin, and cornea were examined by electron microscopy. Differentiation ability of hematopoietic cells, progenitors of granulocytes and macrophages, and DNA synthesis in the cornea were compared in irradiated and nonirradiated animals. None of the parameters tested was affected to an extent that would indicate the start of a pathological process or the risk of damage to genetic material.

Animals↗
PubMed1992

Amelioration of radiation damage to haemopoiesis by Ivastimul, given after irradiation to mice protected by peroral cystamine.

The combined radioprotection by preirradiation peroral cystamine and postirradiation Ivastimul treatment was examined in sublethally and lethally whole-body gamma-irradiated mice. The enhancement of haemopoietic recovery and increased survival of irradiated mice was demonstrated when a single dose of Ivastimul was administered after irradiation. Ameliorative influence of combined radioprotection may be explained by the haemopoietic stem cell protection by cystamine and haemopoietic stimulation mediated by Ivastimul.

Animals↗
PubMed1991

Radioprotective effect of dextran sulphate and aerogenic hypoxia on intestinal crypt stem cells in mice.

A single intraperitoneal injection of dextran sulphate given 6 h before irradiation produced higher numbers of microcolonies of intestinal crypt stem cells in whole-body irradiated mice than injection of saline in control mice. If dextran sulphate and hypoxia are combined, the radioprotective effect of hypoxia on intestinal crypt stem cells depends on the time interval between irradiation and administration of dextran sulphate.

Animals↗
PubMed1991

Decrease in the number of progenitors of erythrocytes (BFUe, CFUe), granulocytes and macrophages (GM-CFC) in bone marrow of rats after a 14-day flight onboard the Cosmos-2044 Biosatellite.

A decrease in the number of progenitors of erythrocytes (BFUe, CFUe) and of granulocytes and macrophages (GM-CFC) in bone marrow was found in rats exposed to microgravitation during a 14-day flight onboard the Cosmos-2044 biosatellite when compared to control rats maintained under conditions of gravitation on the ground. The number of progenitors of both lineages of haemopoiesis was also decreased in synchronous control rats, thus suggesting that the pool of progenitors is influenced also by the action of the nonspecific space flight factors.

Animals↗
PubMed1990

Hydroxyurea as a suppressor of the radioprotective effect of dextran sulfate on bone marrow hemopoietic stem cells in mice.

The changes in hemopoiesis of mice following intraperitoneal administration of dextran sulfate (DS) 24 h before irradiation, as well as the effect of injecting them with hydroxyurea (HU), were analyzed. DS increased the proliferation activity and number of hemopoietic stem cells (CFUs) in the bone marrow. The content of CFUs in the bone marrow and the number of endogenous spleen colonies (ESC) of hemopoietic tissue were higher after irradiation in mice treated with DS than in control groups. The survival rate following a lethal radiation dose was also higher. Injection with HU decreased the number of CFUs in animals injected with DS to the level of controls and suppressed its radioprotective effect.

Animals↗
PubMed1990

Decrease in the number of progenitors of fibroblasts (CFUf) in bone marrow of rats after a 14-day flight onboard the Cosmos-2044 biosatellite.

A decrease in the number of progenitors of fibroblasts (CFUf) was found in bone marrow of rats that underwent a 14-day flight in the state of weightlessness onboard the Cosmos-2044 biosatellite, immediately after flight, when compared with rats maintained in control conditions of terrestrial gravitation. These changes may be explained by the action of specific factors of microgravitation.

Animals↗
PubMed1990

Radioprotection of hemopoiesis conferred by aqueous extract from chlorococcal algae (Ivastimul) administered to mice before irradiation.

In experiments on mice, single i.p. injections of aqueous extract from chlorococcal freshwater algae (Ivastimul) were found to increase their radioresistance. During the same period the number of spleen colony-forming units (CFUs) in the bone marrow and spleen and their proliferation activity increased. The amount of granulocyte-macrophage colony-forming cells (GM-CFC) in the bone marrow grows and the colony-stimulating activity (CSA) of the blood serum of mice is elevated at an early period after injection of the substance. The recovery of the CFUs and GM-CFC pools in femoral bone marrow after irradiation proceeds at a faster rate in Ivastimul-treated animals than in control groups. The activation of the pool of hemopoietic stem cells and stimulatory effects of Ivastimul on granulocytopoiesis act favorably on the repair of radiation damage and on increased percentage of animals surviving lethal doses of gamma radiation.

Animals↗
PubMed1989

The radioprotective effects of aqueous extract from chlorococcal freshwater algae (Chlorella kessleri) in mice and rats.

In experiments on mice and rats the effect was studied of a single administration of aqueous extract from chlorococcal freshwater algae - Ivastimul - on their radiosensitivity. After injection of this substance the number of haemopoietic stem cells in the bone marrow and spleen of mice (CFUs) increased, as did their survival after irradiation. Irradiation with a lethal dose of gamma rays 24 hours after the injection of Ivastimul is survived by a larger number of treated mice and rats than untreated ones. On the first day after the administration Ivastimul protects mice against brief and prolonged action of irradiation. The protective effect of Ivastimul was observed after intraperitoneal, intramuscular and subcutaneous administration.

Animals↗
PubMed1988

[Enhancement of the radioprotective action of gas-induced hypoxia by using dextran sulfate].

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.

Animals↗
PubMed1987

Effects of microwaves on the colony-forming capacity of haemopoietic stem cells in mice.

A suspension of bone marrow cells from femurs of female (CBA X C57Bl)F1 mice was exposed to 2450 MHz CW microwaves in a specially designed waveguide exposure system. The temperature of the suspension rose, during exposure to microwaves, from 20 degrees C to 45 degrees C, and at an interval within 20 degrees C to 45 degrees C the number of haemopoietic stem cells (CFUs) was determined by the spleen exocolony method. The time of exposure of bone marrow cells to each temperature studied was 20 s. Control suspensions of bone marrow cells were exposed to a water bath temperature. There were no significant effects of the CFUs with the water bath temperature, while after exposure to microwaves the number of spleen colonies was elevated with a nadir at the temperature of 37 degrees C. With a microwave-induced increase of the temperature above 41 degrees C the number of CFUs in the bone marrow suspension decreased. The increase in the number of colonies was related to the rise in the seeding rate of the CFUs as well as to a rise in their proliferative activity, while the drop in the number of colonies was influenced also by heat-killing of the CFUs by microwave exposure.

Animals↗
PubMed1985

Changes in the number of haemopoietic stem cells (CFUs) in bone marrow and spleens of pregnant rats after a short space flight onboard the Cosmos-1514 biosatellite.

After a 5-day stay in a state of weightlessness onboard a biosatellite Cosmos-1514 the pregnant rats exhibited a decrease in the number of haemopoietic stem cells (CFUs) in bone marrow and spleens on the recovery day after the space flight as compared to rats kept in the vivarium under usual conditions. The different changes in the concentration of CFUs in the bone marrow and spleens of flight and synchronous control rats indicate that the extent of the decrease in CFUs pool in the spleens of flight rats was significantly influenced by the action of non-specific flight factors.

Animals↗