HEMATOPOIETIC PROGENITORS CELLS IN PERIPHERAL BLOOD OF BALB/C MICE UNDER IONIZING RADIATION ACTION IN SUBLETHAL DOSE.

Objective: determination of the content of hematopoietic progenitor cells circulating in peripheral blood of Balb/Cmice, under ionizing radiation action in sublethal dose, at different periods after the irradiation, using cell culturein diffusion chambers in vivo.

Methods: Peripheral blood smears of Balb/C mice were prepared and studied, its cellular composition was determined, as well as by cultivation of peripheral blood cells in diffusion chambers in vivo their colony-forming efficien-cy was determined on the 0th, 5th, and 30th day after external irradiation in sublethal dose 5.85 Gy.

ANALYSIS OF THE INFLUENCE OF PROLONGED IRRADIATION ON HEMATOPOIETIC PROGENITOR CELLS IN GEL DIFFUSION CHAMBERS USING MATHEMATICAL MODELLING.

Objective: determining of the functional activity of mice bone marrow hematopoietic progenitor cells, cultivated in gel diffusion chambers, on the stages of hematopoiesis recovery after their prolonged irradiation in the lethal dose in a comparative aspect with the method of colony forming in spleen using mathematical model.

Materials And Methods: The method of cell cultivation in gel diffusion chambers, cytological methods, mathematical modeling, and statistical methods of research were used. Bone marrow samples extracted from the femur of mice irradiated with a total dose of 8 Gy with a power 0.

HUMANIZED MODEL OF ISOLATED SUSPENSION CULTIVATION OF HEMATOPOIETIC PROGENITOR CELLS FOR THE INVESTIGATION OF IONIZING RADIATION INFLUENCE IN VIVO.

Objective: development of the humanized system for cells cultivation outside the human organism (human-mouse)and investigation of the influence of ionizing radiation in increasing doses on the colony-forming ability ofhematopoietic progenitor cells.

Materials And Methods: Bone marrow samples of individuals without blood system diseases were cultivated in geldiffusion chambers with semi-solid agar in the abdominal cavity of CBA mice exposed to ionizing radiation action.Cell aggregates, which were obtained in the culture of diffusion chambers in vivo, were counted and colony-formingefficiency of bone marrow cells was determined.

COMPARATIVE MATHEMATICAL ANALYSIS OF COLONY-FORMING ABILITYOF THE BONE MARROW OF MICE LETHALLY AND NON-LETHALLY IRRADIATED WITH EQUAL DOSE RATE INTENSITY.

Objective: To perform comparative analysis of the characteristics of population functioning process of mice bonemarrow colony-forming units after their prolonged irradiation in lethal and non-lethal doses with equal dose rateintensity with the aid of mathematical model.

Materials And Methods: Assigned task is solved by means of mathematical model of alterations in the number ofbone marrow colony-forming units after continuous irradiation, described in previous works, with the use of experimental results of K. S.

ASSESSMENT OF RADIOPROTECTIVE ACTION OF BASIDIOMYCOTIC MELANIN PIGMENTS ON THE HEMATOPOIETIC SYSTEM OF Balb/C MICE UNDER EXPOSURE TO IONIZING RADIATION IN SUBLETHAL DOSE.

Objective: Assessment of radioprotective action of basidiomycotic melanin pigments on hematopoietic stem and progenitor bone marrow cells of Balb/C mice in case of exposure to ionizing radiation in sublethal dose.

Materials And Methods: Using original method of cultivation in gel diffusion chambers in vivo of bone marrow cells of Balb/C mice we investigated the colony-forming efficiency of hematopoietic progenitor cells of the ani- mals, which were exposed to ionizing radiation action in sublethal dose, in case of treatment with melanin pig- ments solution of basidiomycotic fungi as radioprotector.

Results And Conclusions: Investigation of functional activity of bone marrow progenitor cells of Balb/C mice allowed assessing their hematopoiesis state in case of ionizing radiation action, as well as in case of previous treat- ment of the animals with the solution of melanin pigments as radioprotector.

MATHEMATICAL ANALYSIS OF FUNCTIONAL PROPERTIES OF MICE BONE MARROW IN THE INITIAL PHASE OF ACUTE FRACTIONATED IRRADIATION.

Objective: to determine the quantitative characteristics of population functioning of mice bone marrow colony-forming units during seven days of acute fractionated irradiation.

Materials And Methods: Assigned task is solved by means of described in works R. V.

Mesenchymal stem and progenitor cells of rats' bone marrow under chronic action of ionizing radiation.

Unlabelled: Under the influence of ionizing radiation on hematopoietic system, the level of its injury is determined not only by the radiosensitivity of hematopoietic stem cells, but also by radiation induced changes in microenvironment func tioning, in particular, mesenchymal stem cells as its components.

Objective: to define functioning characteristics of mesenchymal stem and progenitor cells of rats' bone marrow under prolonged action of ionizing radiation as a result of 90Sr incorporation.

Materials And Methods: We applied the model of Wistar rats' internal irradiation with 90Sr radionuclide and per formed the in vitro cultivation of their bone marrow mesenchymal cells.

Circulating hematopoietic progenitor cells in patients affected by Chornobyl accident.

Unlabelled: High radiation sensitivity of stem cells and their ability to accumulate sublethal radiation damage provides the basis for investigation of hematopoietic progenitors using in vivo culture methodology. Unique samples of peripheral blood and bone marrow were derived from the patients affected by Chornobyl accident during liquidation campaign.

Aim: To investigate functional activity of circulating hematopoietic progenitor cells from peripheral blood and bone marrow of cleanup workers in early and remote periods after the accident at Chornobyl nuclear power plant (CNPP).

Pattern changes in quantitative and qualitative markers of hematopoietic stem cells during acute and chronic exposure to 90Sr isotope in cell culture.

Objective: The objective of our research was investigation of the hematopoietic system of laboratory rats under the influence of acute and chronic internal exposure to 90Sr isotope.

Materials And Methods: To study the condition of stem cells and their immediate progenitors we implemented cell culture methodology in vivo in gel diffusion capsules with subsequent analysis of the colonies and clusters.

Results: On the basis of experiments it was established that long-term effects of incorporated 90Sr isotope leads to significant disturbances in the hematopoietic system and in particular, revealing changes in hematological parameters of irradiated animals such as the appearance of circulating progenitor cells in peripheral blood, reducing the colony-forming efficiency of the bone marrow derived progenitor cells, as well as quantitative and qualitative changes in the clones.

Mechanisms of resistance in patients with chronic myeloid leukemia treated with tyrosine kinase inhibitors.

Up to date, two major mechanisms have been proposed as an explanation for myeloid cells expansion in chronic myeloid leukemia (CML). One is a reduced susceptibility of hematopoietic stem or progenitor cells to apoptosis, while the other one is an increased activity within the hematopoietic progenitor cell population. The aim of the study was to identify specific features of functional activity, proliferation rates and differentiation potential of CML hematopoietic progenitor cells of patients treated with tyrosine kinase inhibitors (TKI) by identifying number of Ki-67, Bcl-2 and CD34 positive cells in bone marrow, as well as in vitro colony-forming unit assay in patients with different response to the TKI therapy.

Functional activity of CD34-positive cells in chronic myeloid leukemia patients with different response to imatinib therapy.

Introduction: It is believed that the reason of the leukemic clone cell resistance to treatment with tyrosine kinase inhibitors during chronic myeloid leukemia (CML) is mutations in the genome of an early bone marrow progenitor cells that are CD34-positive. Such cells, regardless of treatment, acquire ability to proliferation and differentiation. This leads to the re-expansion of the CD34(+) cells.

Character of interaction between irradiated and non-irradiated cells in culture in diffusion chambers in vivo.

Objective: Current investigation is devoted to determination of interaction type between the non-irradiated murine bone-marrow cells and irradiated microenvironment in cell culture in diffusion chambers in vivo.

Materials And Methods: To study the characteristics of interaction between the cells we implemented an original cultivation model with bone-marrow cells of intact Balb/c mice inserted in the diffusion chambers in peritoneum of irradiated animals (it provided the access of nutrients and signaling molecules from outside).

Results: As a result of investigations performed, we have determined the direct influence of microenvironment factors of irradiated mice organism on the non-irradiated bone-marrow cells.

Determination of the optimal chemotherapy drugs pretreatment time through cultivation of hemopoietic cells in CML-patients treated with tyrosine kinase inhibitors.

Background: Targeted therapy drugs, including imatinib, are used for inhibiting the marker oncoprotein of chronic myeloid leukemia - BCR-ABL tyrosine kinase. However, in some patients the drug resistance can emerge too rapidly and a previous treatment with chemotherapy drugs can lead to formation of resistance.

Aim: To evaluate the influence of drugs that were used prior to the imatinib on the performance of the functional activity of bone marrow cells from chronic myeloid leukemia patients and their individual responses to therapy.

Characterization of the interactions between stromal and haematopoietic progenitor cells in expansion cell culture models.

Development of the long-term culture models of haematopoietic stem cells (HSCs) is one of the important tasks in modern biotechnology. It has been suggested that stromal presence is important for haematopoiesis in vitro and in vivo, but the question remains: whether diffusible factors produced by stromal cells are sufficient for the regeneration of primitive and definitive haematopoietic cells, or direct cell-to-cell contacts of the cultured material with underlying stromal base would be required. During present studies, influence of various feeder layers and feeder layer conditioned media on proliferative, differentiative and clonogenic activity of human AC133+ derived from human umbilical cord blood was investigated.

The role of poly (adenosine 5'-diphosphate-ribose) polymerase in the response of pituitary tumor cells to reactive oxygen species.

As an enzyme implicated in the stress response, we investigated poly(ADP-ribose) polymerase (PARP) in the response of GH3 rat pituitary tumor cells to oxidants. These cells are unusual in that they undergo rapid cell death (90 min) with low doses of the prooxidant, H2O2 (50-200 microm), whereas at higher doses (1 mm), death occurs some hours later (4-5 h). Measurement of PARP activity shows that low doses of H2O2 (50-200 microm) fail to increase the activity of PARP, whereas at 0.

The sesame seed oil constituent, sesamol, induces growth arrest and apoptosis of cancer and cardiovascular cells.

Sesamol is a potent inhibitor of fungal fatty acid biosynthesis. This effect is apparently due to inhibition of malic enzyme and the supply of NADPH that is required for this biosynthetic pathway. It is the ability of sesamol to reduce the synthesis of the coenzyme, NADPH, that makes it attractive for use in studying the effect of oxidants on tumor and vascular endothelial cells.

Statin-induced apoptosis of vascular endothelial cells is blocked by dexamethasone.

Statins block de novo synthesis of cholesterol by inhibiting the enzyme, HMG CoA reductase. The product of this reaction, mevalonic acid, is also a precursor of isoprenoids, molecules required for the activation of signalling G-proteins, such as Ras. Signal transduction pathways involving Ras are important for cell survival and this may be why statins induce apoptotic death of several cell types.

Dexamethasone blocks antioestrogen- and oxidant-induced death of pituitary tumour cells.

The oestrogen receptor is fundamental to the growth and survival of the rat pituitary tumour cell line, GH(3). Our previous studies have shown that antioestrogens such as RU 58668 and ZM 182780 will reduce the rate of cell division and also induce cell death. Death of these cells in response to antioestrogen treatment appears to be due to a heightened sensitivity to reactive oxygen species (ROS).