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Haematopoietic System (haematopoietic + system)
Selected AbstractsThe essential haematopoietic transcription factor Scl is also critical for neuronal developmentEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2006Cara K. Bradley Abstract The basic helix-loop-helix (bHLH) transcription factor Scl displays tissue-restricted expression and is critical for the establishment of the haematopoietic system; loss of Scl results in embryonic death due to absolute anaemia. Scl is also expressed in neurons of the mouse diencephalon, mesencephalon and metencephalon; however, its requirement in those sites remains to be determined. Here we report conditional deletion of Scl in neuronal precursor cells using the Cre/LoxP system. Neuronal-Scl deleted mice died prematurely, were growth retarded and exhibited an altered motor phenotype characterized by hyperactivity and circling. Moreover, ablation of Scl in the nervous system affected brain morphology with abnormal neuronal development in brain regions known to express Scl under normal circumstances; there was an almost complete absence of Scl-null neurons in the hindbrain and partial loss of Scl-null neurons in the thalamus and midbrain from early neurogenesis onwards. Our results demonstrate a crucial role for Scl in the development of Scl-expressing neurons, including ,-aminobutyric acid (GABA)ergic interneurons. Our study represents one of the first demonstrations of functional overlap of a single bHLH protein that regulates neural and haematopoietic cell development. This finding underlines Scl's critical function in cell fate determination of mesodermal as well as neuroectodermal tissues. [source] The development of integrated haematopathology laboratories: a new approach to the diagnosis of leukaemia and lymphomaINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 6 2003S. J. Richards Summary The diagnosis and monitoring of leukaemia and lymphoma requires the effective integration of a wide range of diagnostic techniques and expertise. The need to develop this type of service that crosses traditional boundaries of laboratory specialities is being recommended in national guidance. The Haematological Malignancy Diagnostic Service based within the Leeds Teaching Hospitals NHS Trust was established in 1993 to provide specialist laboratory services for the diagnosis of haematological malignancy for Yorkshire and Humberside in the UK. The department uses a wide range of methodologies including morphology, immunocytochemistry, flow cytometry and molecular genetics [fluorescent in situ hybridization (FISH) and polymerase chain reaction (PCR)] in a systematic and co-ordinated way. We describe how the department was established, its current working practices and highlight the advantages of an integrated laboratory for diagnosis of tumours of the haematopoietic system. [source] Haematopoietic stem cell niche in DrosophilaBIOESSAYS, Issue 8 2007Ute Koch Development and homeostasis of the haematopoietic system is dependent upon stem cells that have the unique ability to both self-renew and to differentiate in all cell lineages of the blood. The crucial decision between haematopoietic stem cell (HSC) self-renewal and differentiation must be tightly controlled. Ultimately, this choice is regulated by the integration of intrinsic signals together with extrinsic cues provided by an exclusive microenvironment, the so-called haematopoietic niche. Although the haematopoietic system of vertebrates has been studied extensively for many decades, the specification of the HSC niche and its signals involved are poorly understood. Much of our current knowledge of how niches regulate long-term maintenance of stem cells is derived from studies on Drosophila germ cells. Now, two recently published studies by Mandal et al.1 and Krezmien et al.2 describe the Drosophila haematopoietic niche and signal transduction pathways that are involved in the maintenance of haematopoietic precursors. Both reports emphasize several features that are important for controlling stem cell behavior and show parallels to both the vertebrate haematopoietic niche as well as the Drosophila germline stem cell niches in ovary and testis. The findings of both papers shed new light on the specific interactions between haematopoietic progenitors and their microenvironment. BioEssays 29:713,716, 2007. © 2007 Wiley Periodicals, Inc. [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] | ||||||||||