Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0002874 (aplastic anemia)
 5,905 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A human megakaryoblastic cell line (MEG-01) was investigated for the presence of protein S in culture medium and cell lysates using a specific enzyme-linked immunoassay (ELISA) and a functional assay. When 5 X 10(5) MEG-01 cells/mL was subcultured in RPMI 1640 medium with 10% fetal calf serum (FCS), the concentration of protein S antigen in the culture medium increased progressively with time from less than 8 ng/mL on day 0 to 105.6 +/- 6.0 ng/mL on day 13. Vitamin K2(1 microgram/mL) increased the production of functional protein S, whereas warfarin (1 microgram/mL) profoundly decreased the quantity and the specific activity of secreted protein S. By an indirect immunofluorescent technique, protein S antigen was detected in both MEG-01 cells and human bone marrow megakaryocytes. Immunoblot analysis of culture medium revealed two distinct bands (mol wt 84,000 and 78,000) that are identical to the doublets of purified plasma protein S. De novo synthesis of protein S was demonstrated by the presence of specific immunoprecipitable radioactivity in the medium after 5 hours of labeling of the cells with [35S]-methionine as a 84,000 mol wt protein. Plasma protein S levels of nine patients with severe aplastic anemia were not significantly different from those of normal controls. These results suggest that megakaryocytes produce functional protein S and contain the enzymes required for the carboxylation of selected glutamic acid residues, and that protein S synthesized by megakaryocytes does not represent a main source of plasma protein S.
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PMID:Biosynthesis and secretion of functional protein S by a human megakaryoblastic cell line (MEG-01). 243 51

Using procedures that were effective in the purification of human urinary erythropoietin (Epo), we attempted initial purification of megakaryocyte colony-stimulating factors (CSF) in urinary extracts from patients with aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP). Comparison of colony stimulation by purified human Epo and crude urinary extracts revealed: (1) that the pure Epo augments megakaryocyte colony formation in culture and (2) MEG-CSF activity is also present in materials other than Epo in the crude urinary extracts from the two types of patients. Similar to purification of Epo, ethanol precipitation and sulfopropyl-Sephadex chromatography provided twofold and threefold increases in the specific activity of MEG-CSF, respectively. In contrast to Epo, however, significant inactivation of MEG-CSF activity was seen with phenol treatment. The elution profile of MEG-CSF seen on hydroxylapatite chromatography of urinary extracts was different from that of Epo. These data provided a basis for initial steps for purification of MEG-CSF and support the notion that MEG-CSF is distinct from Epo.
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PMID:Characterization of human megakaryocyte colony-stimulating factor in the urinary extracts from patients with aplastic anemia and idiopathic thrombocytopenic purpura. 660 Jun 33

The urinary extracts from patients with aplastic anaemia and from healthy donors were investigated in vivo and in vitro for their ability to stimulate megakaryopoiesis and platelet production. There was a significantly higher concentration of thrombopoiesis stimulating factor (TSF) and megakaryocyte colony stimulating factor (MEG-CSF) in the urine from patients with aplastic anaemia than in that from healthy donors. Neuraminidase treatment did not affect the thrombopoietic activity of TSF, whereas coexisting erythropoietin (EPO) in the extract lost in its activity in vivo. These findings suggest that TSF and/or MEG-CSF seems to be different from EPO and that the urine from aplastic anaemia patients would be a good source of TSF and MEG-CSF for purification and characterization.
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PMID:Thrombopoiesis and megakaryocyte colony stimulating factor in the urine of patients with aplastic anaemia. 696 85

The urinary extract from patients with severe, chronic idiopathic thrombocytopenic purpura (ITP) was capable of inducing significant thrombocytosis in rats in vivo and enhancing megakaryocyte colony formation in culture of mouse bone marrow cells. The apparent specific activity of megakaryocyte colony stimulating factor (MEG--CSF) in the ITP extract was approximately one-half of that of the urinary extract from patients with aplastic anaemia (AA). Daily injections of ITP extract did not cause an increase in Hb concentration, while rats receiving AA urinary extract revealed profound erythropoiesis 3 weeks later. In vitro assay of erythropoietin (EPO) failed to show significant EPO activity in the extract from patients with ITP. These findings excluded the possibility that the observed activities of thrombopoiesis-stimulating factor (TSF) and MEG--CSF in the ITP urinary extract are due to contaminating EPO. Urine of patients with severe ITP appears to be a good source of TSF and MEG--CSF.
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PMID:Thrombopoiesis- and megakaryocyte colony-stimulating factors in the urine of patients with idiopathic thrombocytopenic purpura. 697 2

Megakaryocyte colon-stimulating factor (MEG-CSF) in the urinary extracts from patients wit aplastic anaemia (AA) revealed two distinct peaks of activity on Sephadex G-200 gel filtration with apparent molecular weights of 155,000 and 76,000. Both fractions induced significant thrombocytosis in peripheral blood and megakaryocytosis in the spleen of rats. Heterogeneity of MEG-CSF was also found in the extracts from the urine of patients with idiopathic thrombocytopenic purpura. The higher molecular weight MEG-CSF was significantly reduced when the gel filtration was performed under the dissociating conditions. Ion-exchange chromatography indicated that the higher molecular weight MEG-CSF had a different charge from the lower molecular weight MEG-CSF. These results suggest that the apparent heterogeneity of MEG-CSF is due to interaction of MEG-CSF with other proteins in the urinary extracts.
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PMID:Apparent heterogeneity of human megakaryocyte colony- and thrombopoiesis-stimulating factors: studies on urinary extracts from patients with aplastic anaemia and idiopathic thrombocytopenic purpura. 698 64