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Peripheral Blood CD34+ Cells (peripheral + blood_cd34+_cell)
Selected AbstractsThe expression of cytosolic phospholipase A2 and biosynthesis of leukotriene B4 in acute myeloid leukemia cellsEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2007Gudmundur Runarsson Abstract Leukotrienes (LT) exert stimulatory effects on myelopoiesis, beside their inflammatory and immunomodulating effects. Here, we have studied the expression and activity of the enzymes involved in the synthesis of leukotriene B4 (LTB4) in acute myeloid leukemia (AML) cells (16 clones) and G-CSF mobilized peripheral blood CD34+ cells. CD34+ cells from patients with non-myeloid malignancies expressed cytosolic phospholipase A2 (cPLA2), 5-lipoxygenase activating protein (FLAP), and leukotriene A4 (LTA4) hydrolase but not 5-lipoxygenase (5-LO). The enzyme cPLA2 was abundantly expressed in AML cells and the activity of the enzyme was high in certain AML clones. The expression of 5-LO, FLAP, and LTA4 hydrolase in AML clones was in general lower than in healthy donor polymorphonuclear leukocytes (PMNL). The calcium ionophore A23187-induced release of [14C] arachidonic acid (AA) in AML cells was low, compared with PMNL, and did not correlate with the expression of cPLA2 protein. Biosynthesis of LTB4, upon calcium ionophore A23187 activation, was only observed in five of the investigated AML clones and only three of the most differentiated clones produced similar amounts of LTB4 as PMNL. The capacity of various cell clones to produce LTs could neither be explained by the difference in [1 , 14C] AA release nor 5-LO expression. Taken together, these results indicate that LT synthesis is under development during early myelopoiesis and the capacity to produce LTs is gained upon maturation. High expression of cPLA2 in AML suggests a putative role of this enzyme in the pathophysiology of this disease. [source] Estimation of haemopoietic progenitor cells in peripheral blood by the Advia 120 and BD vantage flow cytometer: a direct comparison for the prediction of adequate collectionsINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 5 2005H. M. GREENFIELD Summary Peripheral blood stem cells are increasingly used to ensure rapid haematological engraftment after myeloablative chemotherapy. After mobilization, progenitor cells in the blood can be enumerated to predict an adequate collection by leukapheresis. The Advia 120 automated counter has an immature cell channel measuring a parameter known as large undifferentiated cells (LUC's), which were quantified to assess their value in refining the timing of apheresis. Data were available from 102 apheresis sessions. Positive correlation was found for peripheral blood CD34+ cells and apheresis counts (r = 0.82, P < 0.0005) but not for total WCC (r = ,0.15, P = 0.13) or LUC count (r = 0.12, P = 0.23). Our results indicate that the LUC population in peripheral blood has no relevance to the subsequent CD34 content of the apheresis product and CD34 cell enumeration by flow cytometry is advocated. [source] In vivo gene marking of rhesus macaque long-term repopulating hematopoietic cells using a VSV-G pseudotyped versus amphotropic oncoretroviral vectorTHE JOURNAL OF GENE MEDICINE, Issue 4 2004Patricia A. Shi Abstract Background Gene transfer efficiency into primitive hematopoietic cells may be limited by their expression of surface receptors allowing vector entry. Vectors pseudotyped with the vesicular stomatitis virus (VSV-G) envelope do not need receptors to enter cells, and therefore may provide superior transduction efficiency. Methods Using a competitive repopulation model in the rhesus macaque, we examined in vivo gene marking levels of blood cells transduced with two vectors: (i) a VSV-G pseudotyped retrovirus and (ii) a conventional amphotropic retrovirus. The VSV-G vector, containing the human glucose-6-phosphate dehydrogenase (G6PD) gene, was constructed for treatment of severe hemolytic anemia caused by G6PD deficiency. Three myeloablated animals were transplanted with peripheral blood CD34+ cells, half of which were transduced with the VSV-G vector and the other half with the amphotropic vector. Results In all animals post-transplantation, levels of in vivo marking in circulating granulocytes and mononuclear cells were similar: 1% or less with both vectors. In one animal, the human G6PD enzyme transferred by the VSV-G vector was expressed in erythrocytes, early after transplantation, at a level of 45% of the endogenous rhesus G6PD protein. Conclusions In a clinically relevant animal model, we found similar in vivo marking with a VSV-G pseudotyped and a standard amphotropic oncoretroviral vector. Amphotropic receptor expression may not be a limiting factor in transduction efficiency, but VSV-G pseudotypes possess other practical advantages that may make them advantageous for clinical use. Copyright © 2004 John Wiley & Sons, Ltd. [source] A mathematical model of haemopoiesis as exemplified by CD34+ cell mobilization into the peripheral bloodCELL PROLIFERATION, Issue 4 2004M. N. Obeyesekere This minimal model reflects the known kinetics of haemopoietic progenitor cells, including peripheral blood CD34+ cells, white blood cells and platelets, in the presence of granulocyte colony-stimulating factor. Reproducing known perturbations within this system, subjected to granulocyte colony-stimulating factor treatment and apheresis of peripheral blood progenitor cells (CD34+ cells) in healthy individuals allows validation of the model. Predictions are made with this model for reducing the length of time with neutropenia after high-dose chemotherapy. Results based on this model indicate that myelosuppressive treatment together with infusion of CD34+ peripheral blood progenitor cells favours a faster recovery of the haemopoietic system than with granulocyte colony-stimulating factor alone. Additionally, it predicts that infusion of white blood cells and platelets can relieve the symptoms of neutropenia and thrombocytopenia, respectively, without drastically hindering the haemopoietic recovery period after high dose chemotherapy. [source] | |||||||||||||