The in vitro radiation sensitivity of CPU-Meg isolated from human placental and umbilical cord blood was evaluated in plasma clot cultures stimulated by recombinant human cytokines, including thrombopoietin, the FLT3 ...
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The in vitro radiation sensitivity of CPU-Meg isolated from human placental and umbilical cord blood was evaluated in plasma clot cultures stimulated by recombinant human cytokines, including thrombopoietin, the FLT3 ligand (FLT3LG), interleukin-3, interleukin-11 and stem cell factor. The CD34(+) cells were irradiated with X rays at a dose rate of 73 cGy/min, The megakaryocyte colonies were identified by using an FITC-conjugated antibody to glycoprotein IIbIIIa and were classified into two groups based on colony size: large colonies (immature CPU-Meg) and small colonies (mature CPU-Meg), Treatment with thrombopoietin alone or in combination with FLT3LG and/or interleukin-11 gave exponential radiation survival curves (D-0 for immature CFU-Meg = 56-77 cGy, D-0 for mature CPU-Meg = 86 cGy-1.12 Gy), while marked shoulders were observed on the survival curves for colonies supported by the combination of thrombopoietin, interleukin-3 and stem cell factor (D-0 for immature CFU-Meg = 89-98 cGy;D-0 for mature CFU-Meg = 1.25-1.31 Gy). Our results showed that the immature CPU-Meg were more radiosensitive than the mature CPU-Meg and that the combination of cytokines, including thrombopoietin, interleukin-3 and stem cell factor, affected the radiation sensitivity of CFU-Meg to the same extent as with thrombopoietin alone or in combination with FLT3LG and/or interleukin-11. (C) 2000 by Radiation Research Society.
After a survey of the literature dealing with the demonstration of platelet autoantibodies by immunofluorescence techniques, the results are given of a study in which immunofluorescence microphotometry was used for th...
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After a survey of the literature dealing with the demonstration of platelet autoantibodies by immunofluorescence techniques, the results are given of a study in which immunofluorescence microphotometry was used for this purpose. The serum of 58, the platelets of 34, and the megakaryocytes of 2 patients with thrombocytopenia were investigated. In 21 of 52 sera (40%) in which the presence of platelet autoantibodies could be expected, positive results were obtained that could not be due to isoantibodies, either because the patients had not been pregnant and had not received blood transfusions or because the reactivity of the serum with the patient's own platelets was demonstrated. The platelets of 28 patients with thrombocytopenia not due to a platelet defect or decreased thrombopoiesis were investigated. In the platelets of 15 (54%) of these, significant differences in fluorescence were found with anti-immunoglobulin conjugate as well as with anti-IgG, -IgA, -IgM, or -complement reagents. It was concluded that in these patients in vivo sensitization of the platelets with autoantibody was demonstrated. In two patients an indication of the in vivo sensitization of the megakaryocytes was also obtained.
The clinical course of a patient with acute monocytic leukemia and prominent infiltration of the skin and testes is described. In vitro studies demonstrated that the circulating monocyte precursors were capable of adh...
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The clinical course of a patient with acute monocytic leukemia and prominent infiltration of the skin and testes is described. In vitro studies demonstrated that the circulating monocyte precursors were capable of adherence to nylon fibers, and phagocytosis of bacteria and latex particles. In vivo, migration of leukemic cells to skin windows was observed. Extreme nuclear folding, marked surface activity, and morphologic features suggesting nuclear and cytoplasmic maturation were seen by light and electron microscopy. The presence of morphologically and functionally more differentiated monocytic cells may account for the marked tissue invasion in this patient and, possibly, in other patients with monocytic leukemia.
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