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Biomedical subjects

D Rotkovská

Publications and source records attributed to D Rotkovská.

At least 37 records · Page 2Linked to original sources
PubMed1981

Radioprotective effects of dextran sulphate in mice.

Influence of a single i.p. injection of dextran sulphate on radiosensitivity of mice was investigated. The administration of dextran sulphate 24, 48 and 72 hours prior to irradiation increased formation of endogenous colonies of the hemopoietic tissue on the surface of the spleen. DRF calculated from an equieffective exposure for 5 colonies was 1.96 when dextran sulphate was administered 24 hours before irradiation, and 2.25 when dextran sulphate was administered 72 hours before irradiation. The radioprotective effects of dextran sulphate were manifested also in the survival of animals exposed to lethal doses of short-termed as well as long-termed gamma radiation.

Animals↗
PubMed1979

Decrease in the ability of bone marrow CFUs to produce macroscopic colonies of haematopoietic tissue in the spleens of partially irradiated young rats.

Experiments were carried out on Wistar rats aged from 3--5 weeks, in order to determine the repopulation capacity of bone marrow CFUs after total body and partial body irradiation. CFUs were derived either from the own marrow, or from bone marrow of isologous donors. In totally irradiated hosts, macroscopic spleen colonies were formed after transplantation of both autologous and isologous marrow cells, whereas no visible colonies were detectable in partially irradiated rats, in spite of an increased haematopoietic activity of the spleen and higher concentration of circulating CFUs. Intravenous application of trypsin resulted in an increase in the number of CFUs in peripheral blood in both intact and partially irradiated rats. CFUs derived from bone marrow of PBR rats form MSC only when transplanted into isologous TBR recipients, but not at autorepopulation. The possibility is discussed that a repressor is released from unirradiated bone marrow of young rats which inhibits the colony-forming capacity of migrating CFUs.

Animals↗
PubMed1978

Effect of hyperthyroidism on haemopoietic stem cell kinetics in mice.

Changes in the pool of haemopoietic colony-forming units (CFUs) of bone marrow and spleen were studied in experiments with mice fed dried thyroid gland (TH) for 21 days, and during the 13 days that followed feeding. After HU treatment, the number of CFUs in DNA synthesis was estimated. As early as the second day of TH treatment, the pool of CFUs is gradually increased, leading to an increase in the total number of splenic and bone marrow CFUs persisting after TH treatment for the period examined. Simultaneously, the numbers of nucleated cells in the bone marrow and spleen are increased. During TH feeding and following its termination, the total number of erythrocytes and the haematocrit values did not change significantly, whereas an increased number of leucocytes was observed in the peripheral blood after TH treatment. Elevation of the proliferative activity of CFUs occurred early in the period of TH treatment, with the maximum attained by end of the first week of TH feeding. This suggests a rapid response of the haemopoietic stem cell compartment to the administration of TH hormones. The participation of humoral factors controlling CFUs compartments in the mechanism of the stimulatory effect of TH hormones on haemopoietic stem cells is discussed.

Animals↗
PubMed1978

Protective effect of a mixture of radioprotective substances (AET and mexamine) on the haemopoietic stem cells of mice.

A protective effect of a combined application of radioprotectors (AET -i.p., mexamine -s.c.) was studied in experiments on mice. Duration of the protective effect on the haemopoietic stem cells and on the survival of mice after a lethal exposure to X-ray radiation lasted for 5 hours after the injection. DRF calculated from a change of LD 50/30 reached the maximum (1.53) within 30 min after the injection, and was equal to 1.17 within an interval of 5 hrs. The protection of haemopoiesis, as expressed by DRF calculated from an equieffective exposure for 2 ESC, reached the maximum within a 60 min interval after the injection (DRF=3.4). D0 calculated from the CFU survival curves of endogenous haemopoietic tissue colonies (ESC) was, within a 120 min interval, almost three times higher (310 R) than in the control group (110 R). After the injection of radioprotectors a greater number of haemopoietic CFU survives at an exposure of 100-400 R than after mere irradiation. The postirradiation decrease in the weight of small intestine was smaller in protected animals than in the controls. The role of a decrease of the radiation damage to the haemopoietic stem cells in the total protective effect of the radioprotectors used is discussed.

Animals↗
PubMed1975

The effect of electromagnetic radiation on the hematopoietic stem cells of mice.

An increase in the leukocyte number in blood and a decrease in the total cell volume of the bone marrow and spleen were observed in mice after wholebody microwave irradiation (2450 MHz, lambda equals 12.5 cm, 100 mW/cm-2). The number of hematopoietic stem cells increased early after microwave irradiation (1626 plus or minus 53 CFU in bone marrow, 689 plus or minus 86 CFU in the spleen), as compared with that or control (598 plus or minus 92 and 349 plus or minus 79 CFU, respectively). Incorporation of 59Fe in the spleen decreased to 78% of the control value 24 hr after irradiation, which was followed by an increase to 250% on Day 14 after irradiation. After heat exposure, CFUs showed an early decrease in number, whereas the percentage of 59Fe incorporation increased. The different effects of microwaves and externally applied heat on the hematopoietic stem cells suggested that alterations in tissues caused by high-intensity microwave radiation need not be related only to increased internal temperature.

Animals↗
PubMed1975

On the role of haemopoietic tissue in interstrain differences in radiosensitivity of mice.

Mice of three different strains were classified according to the percentage of survival after a whole-body exposure of 600R as radioresistant (strain C57BL/10), radiosensitive (strain BALB/c) and intermediate (strain BFU). Haemopoietic recovery after a whole-body exposure of 200R was followed in the three groups. It was found that the radiosensitivity of bone marrow and spleen haemopoietic stem cells was equal in all the mouse strains tested. The extent of radiation damage to haemopoiesis, assessed by the changes in nucleated cell counts in bone marrow and spleen, as well as by bone marrow and spleen 59Fe uptake, was smaller and the rate of recovery higher in strain C57BL/10 than in strains BALB/c or BFU. An analogical difference among the strains was also observed during realimentation in the recovery of bone marrow and spleen haemopoiesis inhibited by fasting. The role of the capacity of haemopoietic cell population to repair the induqed haemopoietic damage is discussed and its decrease in BALB/c mice is held responsible for their higher radiosensitivity.

Animals↗
PubMedDate not supplied

Increased protective effect of hypoxia against radiation following activation of haemopoiesis with dextran sulphate.

The effect of pretreatment of mice with a single injection of dextran sulphate (DS) on the protective capacity of moderate hypoxia was analysed. Dextran sulphate activated haemopoietic stem cell populations, and irradiation under hypoxia one day after DS injection increased the number of haemopoietic stem cells surviving in the bone marrow of the femur, their recovery after irradiation, and the number of endogenous spleen colonies. A moderate hypoxia (15% O2 and 12% O2) significantly reduced the lethal effect of gamma rays in mice after DS injection and increased the value of LD 50/30.

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