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Burst-forming Unit (burst-forming + unit)
Selected AbstractsHuman hematopoietic stem/progenitor-enriched CD34+ cells are mobilized into peripheral blood during stress related to ischemic stroke or acute myocardial infarctionEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2005E. Paczkowska Abstract:, The hematopoietic and non-hematopoietic stem/progenitor cells harvested directly from the bone marrow (BM) or G-CSF mobilized peripheral blood were demonstrated to play an important role in regeneration of damaged organs (1, 2). Here, we asked if the stroke- or acute heart infarct-related stress triggers mobilization of stem/progenitor-enriched CD34+cells from the BM into the peripheral blood, which subsequently could contribute to regeneration of damaged tissues. To address this question the peripheral blood samples were harvested from patients with ischemic stroke during the first 24 h of manifestation of symptoms and on the second and sixth day afterwards or during the first 24 h of acute cardiac pain as well as on the second and sixth day of infarct. We measured in these patients (i) percentage of circulating hematopoietic stem/progenitor-enriched CD34+ cells in peripheral blood by employing fluorescence activated cell sorter (FACS) and (ii) number of hematopoietic progenitor cells for the granulocyte-monocytic colony-forming unit (CFU-GM) and erythoid burst-forming unit (BFU-E) lineages circulating in peripheral blood. We concluded that stress related to ischemic stroke or acute myocardial infarction triggers the mobilization of hematopoietic stem/progenitor-enriched CD34+ cells from the BM into peripheral blood. These circulating stem/progenitor-enriched CD34+ cells may contribute to the regeneration of ischemic tissues, however, this possibility requires further studies. [source] Changes in murine bone marrow macrophages and erythroid burst-forming cells following the intravenous injection of liposome-encapsulated dichloromethylene diphosphonate (Cl2MDP)EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 4 2001A. L. Giuliani Abstract: In order to explore the effect on bone marrow macrophages of liposome-encapsulated dichloromethylene diphosphonate (Cl2MDP), mice were injected intravenously with a preparation of such liposomes at a dose known to deplete spleen and liver macrophages. Two days later, the macrophages in the marrow of the femoral bones were quantified by flow cytometry using a macrophage-specific monoclonal antibody (F4/80), and their ultrastructure and phagocytic activity towards zymosan particles was assessed. To determine the effect on erythropoiesis of liposome-encapsulated Cl2MDP-induced changes in bone marrow macrophages, red blood cell parameters and the formation of erythroid burst-forming unit (BFU-E)-derived colonies in vitro were evaluated. In mice injected with liposome-encapsulated Cl2MDP, there was a 54% and 67% decrease in the total number of bone marrow macrophages as compared to uninjected controls and mice treated with empty liposomes, respectively. Moreover, residual macrophages showed an abnormal ultrastructure, with reduced numbers of crystalloid inclusions and increased numbers of large myelin figures. However, the phagocytic activity of these cells was unimpaired or slightly enhanced. In mice injected with liposome-encapsulated Cl2MDP there was an approximately 60% decrease in the percentage and total number of circulating reticulocytes and a 54% reduction in the BFU-E number, demonstrating deregulation of erythropoiesis under conditions of macrophage loss and impairment. The results suggest that mice treated with liposome-encapsulated Cl2MDP are a model for studying the role of macrophages in erythropoiesis. [source] The influence of 3,3,,5-triiodo- l -thyronine on human haematopoiesisCELL PROLIFERATION, Issue 3 2007K. Grymu The role of the 3,3,,5-triiodo- l -thyronine (T3) in normal human haematopoiesis at the cellular and molecular levels has not been determined. In this study, it was revealed that the human haematopoietic system might be directly depended on T3 influence. Materials and methods: We detected the TR,1 and TR,1 gene expression at the mRNA level in human cord blood, peripheral blood and bone marrow CD34+ -enriched progenitor cells, using the RT-PCR method. Furthermore, we performed Western blotting to prove TR,1 and TR,1 expression occurs at the protein level in human cord blood, peripheral blood and bone marrow CD34+ cells. In addition, the examined populations of cells were exposed in serum-free conditions to increasing doses of T3 and were subsequently investigated for clonogenic growth of granulocyte-macrophage colony-forming unit and erythrocyte burst-forming unit in methylcellulose cultures, and for the level of apoptosis, by employing annexin V staining and the terminal deoxynucleotidyltransferase-mediated dUTP nick-end labelling method. We investigated expression levels of apoptosis-related Bax and antiapoptotic Bcl-2 and Bcl-xL genes in the examined cells. Results: We found that exposure to higher and lower than normal concentration of thyroid hormone significantly influenced clonogenecity and induced apoptosis in human haematopoietic progenitor cells. Conclusions: This study expands the understanding of the role of thyroid disorders in normal human haematopoiesis and indicates a direct influence of T3 on this process. [source] The influence of antisense oligonucleotides against STAT5 on the regulation of normal haematopoiesis in a bone marrow modelCELL PROLIFERATION, Issue 3 2004M. Ba, kiewicz-Masiuk The STAT5 (signal transducers and activators of transcription) proteins are members of a family of signal transducers and activators of transcription that can be activated after cytokine stimulation. Their binding to promoters of different genes influences cell proliferation, differentiation and survival. It is suggested that they play an important role in haematopoiesis, however, the question of the real function of STAT5 proteins requires further examination. The aim of our study was to investigate the role of STAT5 in the proliferation and apoptosis of normal haematopoietic bone marrow cells derived from heparinized cadaveric organ donors (HCOD). We applied antisense oligodeoxynucleotides (ODNs) to block STAT5A and STAT5B at the mRNA level and the reverse transcription polymerase chain reaction method to study STAT5 mRNA expression in the cells after incubation with ODNs. Moreover, we performed Western blot analysis of the STAT5A protein after exposure to antisense STAT5A. We analysed the clonogenicity of the colony-forming unit of granulocytes,macrophages and the burst-forming unit of erythrocytes in methylcellulose cultures according to the type and the dose of ODNs. We also examined apoptosis induced in bone marrow mononuclear and CD34+ cells by employing annexin V staining and the TUNEL method using flow cytometry (FACScan). We found that the perturbation of STAT5 expression decreased the clonogenicity of bone marrow haematopoietic cells. However, we did not observe any significant increase in the percentage of apoptotic cells after incubation with antisense ODNs. It was concluded that the STAT5 proteins play a significant role in the proliferation of human bone marrow cells harvested from HCOD. These proteins might be critical in the regulation of haematopoiesis, especially under stress conditions. [source] Human thymic epithelial cells maintain long-term survival of clonogenic myeloid and erythroid progenitor cells in vitroBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2000Katsuto Takenaka Precursor cells that migrate into the thymus are still multipotent. Therefore, thymic epithelial cells (TECs) may provide microenvironments not only for T-cell development, but also for maintenance of multipotent precursor cells until they undergo T-cell commitment. In the present study, we performed long-term cultures of CD34+ bone-marrow (BM) cells on TEC lines that were derived from cortical epithelial cells of post-natal thymus, to investigate whether human TECs could maintain long-term non-lymphoid haematopoiesis. Haematopoietic cells maintained in direct contact with established TEC lines were able to generate clonogenic progeny to both myeloid and erythroid cells for periods in excess of 5 weeks. Their abilities to support colony-forming units of granulocytes,macrophages (CFU-GM) and burst-forming units of erythroids (BFU-E) were almost equal to those of BM stromal cells. We observed similar results by using cloned TEC lines derived by limiting dilution, as well as those by using parental TEC lines. Colony-forming activities were maintained even when haematopoietic progenitor cells were physically separated from TEC lines and cultured on microporous membrane. These observations indicate that haematopoiesis maintained in TEC-contact long-term cultures may depend on soluble factors produced by TEC lines. Our results suggest that thymic cortical epithelial cells have the ability to support not only the differentiation of haematopoietic cells, but also long-term survival of clonogenic myeloid/erythroid progenitor cells. [source] | ||||||||||