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)

Human granulocyte-macrophage colony-stimulating factor (GM-CSF) is a glycoprotein hormone that stimulates the growth of hematopoietic progenitor cells and enhances the functional activity of mature myeloid effector cells. Granulocyte-macrophage colony-stimulating factor was administered to eight patients with severe aplastic anemia in an attempt to restore adequate hematopoiesis. Profound decreases in serum cholesterol concentrations were observed during GM-CSF therapy that were not dependent on changes in the patients' peripheral blood cell counts. Serum cholesterol levels decreased by an average of 37% during treatment, reaching levels of less than 4.40 mmol/L in all patients. Serum cholesterol concentrations returned to baseline in all patients after discontinuation of GM-CSF therapy. Treatment with GM-CSF prominently alters cholesterol homeostasis in vivo, although the mechanism of this effect is unknown. Our results suggest that GM-CSF may be potentially useful in the treatment of hypercholesterolemia and, possibly, in the prevention and treatment of atherosclerosis.
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PMID:Serum cholesterol-lowering activity of granulocyte-macrophage colony-stimulating factor. 264 96

Suspensions of enriched human megakaryocytes (MK) devoid of MK progenitors (CFU-MK) undergo complete cytoplasmic maturation in vitro. MK were cultured in the presence of normal human AB serum (NABS) to mimic "normal" development. The rate of maturation was not statistically altered by higher concentrations (10%-20%-30%) of NABS, or by the addition of bovine serum albumin (1.5%-3.0%), but was accelerated in the presence of aplastic anemia serum (AAS). Sera from eight different patients with severe aplastic anemia were effective in accelerating terminal differentiation. MK-CSF, a glycoprotein isolated from AAS, specifically augments MK colony formation by two- to sixfold. Similar doses of MK-CSF were ineffective in altering terminal cytoplasmic maturation. Anti-MK-CSF, a polyclonal antibody prepared against purified MK-CSF, neutralizes the ability of both purified MK-CSF and AAS to promote MK colony formation. However, AAS adsorbed with anti-MK-CSF still retained its ability to accelerate terminal differentiation. Apparently, AAS contains at least two separate humoral factors, which can regulate in vitro human megakaryocytopoiesis: MK-CSF, which stimulates proliferation of the progenitors (CFU-MK), and a maturation factor, which accelerates cytoplasmic maturation of morphologically recognizable megakaryocytes.
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PMID:Effects of megakaryocyte colony-stimulating factor on terminal cytoplasmic maturation of human megakaryocytes. 359 64

In some patients with thrombocytopenia, it is difficult to determine whether the condition is caused by underproduction of platelets (reduced numbers of megakaryocytes) or an increase in the rate of their destruction (normal or increased numbers of megakaryocytes). A non-invasive test to help distinguish between these two categories of thrombocytopenia would be useful. We related the plasma concentration of glycocalicin, a fragment of the platelet-membrane glycoprotein Ib, to the mechanism of thrombocytopenia by evaluating bone marrow megakaryocyte content and measuring platelet life span. Plasma glycocalicin was measured with a monoclonal antibody to the glycocalicin component of platelet glycoprotein Ib. The mean (+/- SD) plasma concentration of glycocalicin in 34 healthy controls was 87 +/- 20 percent of the level in pooled normal plasma (range, 52 to 127 percent). All of eight patients with aplastic anemia or amegakaryocytic thrombocytopenia confirmed by examining bone marrow (in all patients) and by determining the life span of autologous platelets (in six patients) had glycocalicin levels significantly below the normal range (5 to 27 percent). In contrast, each of 25 patients with thrombocytopenia thought to be caused by a reduction in platelet life span, whose bone marrow contained normal or increased numbers of megakaryocytes, had glycocalicin levels that fell within or above the normal range (48 to 261 percent). There was no overlap of values between the two patient populations. These studies indicate that the measurement of plasma glycocalicin may be a useful adjunct in classifying thrombocytopenic disorders.
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PMID:Plasma glycocalicin. An aid in the classification of thrombocytopenic disorders. 365 67

Several studies suggest that serum factors (thrombopoietins) regulate thrombopoiesis by altering the number, size, ploidy, and maturation rate of megakaryocytes (MK). Various in vivo systems have been used to quantitate these events. In this study, an in vitro system was developed to monitor terminal cytoplasmic maturation of isolated human MK. MK enriched by elutriation, which eliminated the MK progenitors, were suspended in culture with serum from either normal donors (NABS) or patients with aplastic anemia (AAS). In cultures composed of small platelet glycoprotein-positive mononuclear cells and morphologically immature MK, development was characterized by sequential shifts in MK through morphologically recognizable maturation stages I, II, III, and IV over eight days of incubation (I and II only; then I, II, III; II, III, IV; III and IV; then IV only). Platelet formation coincided with the appearances of stage IV cells. Cultures composed of a mixture of all stages followed a similar maturation sequence, only at an accelerated rate. AAS resulted in the more rapid appearances of the mature cells in either system. This study indicates that human MK can undergo terminal cytoplasmic maturation in vitro, and that altering culture conditions (AAS for NABS) can accelerate the rate of maturation. Three major events occur during megakaryocytopoiesis: proliferation of the progenitor cells, polyploidization, and cytoplasmic maturation. Now it is possible to study the terminal steps of differentiation independent of proliferative events.
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PMID:Terminal cytoplasmic maturation of human megakaryocytes in vitro. 377 Jan

Plasma fibronectin (FN) is one of the major blood opsonins. The content of the glycoprotein reduces in sepsis which in turn may aggravate the course of the infection. FN is detectable in the content of cryoglobulins and cryofibrinogen. The formation of the heparin precipitate following plasma incubation in the cold in the presence of heparin is determined by FN involvement. Fibrinogen (FG) is another main component of the heparin precipitate. To determine the functional activity of plasma FN in sepsis and other pathological conditions, a study was made of the ability of FN and FG to go into the precipitate formed in blood plasma in the cold after its incubation with heparin. Unlike normal subjects in whom over 80% of FN on the average and about 20% of FG went into the heparin precipitate, in patients with hemoblastoses and aplastic anemia complicated by sepsis, less than 40% of FN on the average and about 7% of FG went into the precipitate. In some patients with sepsis, the heparin precipitate did not form. The reduction of FN ability to go into the heparin precipitate correlated with the gravity of the patients' condition. In uncomplicated hemoblastoses, cryoglobulinemia and cryofibrinogenemia and in immunocomplex pathology, the consumption of FN and FG during heparin precipitate formation did not significantly differ from the control. The data indicate that sepsis patients with blood system pathology may develop not only quantitative FN deficiency in the blood but also disorder of the functional activity of the opsonin.
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PMID:[Decreased effectiveness of cold-induced heparin precipitation of plasma fibronectin in infection]. 379 36

Plasma fibronectin is regarded to play an important part in a decrease of the resistance to infections. To specify the role of fibronectin in the pathogenesis of infectious complications in patients with depressions of hemopoiesis, the content of this opsonin was measured by ELISA in 113 patients with different patterns of hemoblastoses, lymphoproliferative diseases and with an aplastic syndrome. In 42 patients, the concentration of opsonin was measured in the presence of the superimposed infection of varying gravity. The fibronectin content was examined in 39 patients before, during and after completion of the cytostatic polychemotherapy. It turned out that in patients with paraproteinemic hemoblastoses, lymphogranulomatosis, aplastic anemia, chronic lympholeukemia, acute lympho- and myelo(mono)blastic leukemias, cyclic neutropenia, chronic myelosis and hematosarcomas, the concentration of fibronectin remained normal in the absence of infections. The computation of the linear correlation ratio did not reveal any association between the opsonin level and the concentration of neoplastic elements in the peripheral blood. Repeated measurements of the fibronectin level in patients whose underlying disease ran its course in association with marked neoplastic fever failed to detect any deficiency of the glycoprotein. The lowering of the fibronectin level was recorded in patients with a grave concomitant infection of the type of sepsis, necrotic enteropathy and lobar pneumonia. The degree of opsonin deficiency correlated with the patients' disease gravity. Prolonged reduction in the blood fibronectin level was of unfavourable prognostic importance. Cytostatic polychemotherapy, myelotoxic agranulocytosis as well as infectious complications of low gravity did not influence the concentration of fibronectin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Plasma fibronectin level in patients with depression of hematopoiesis]. 404 64

We have recently described an assay system for human peripheral blood megakaryocyte colony-forming unit cells (CFU-M) using an anti-platelet glycoprotein antiserum probe to define megakaryocyte colonies grown in vitro. This system was applied to study the nature and regulation of human bone marrow CFU-M. In the absence of a specific megakaryocyte growth-promoting factor, 12.4 +/- 3.0 (means +/- SEM) megakaryocyte colonies were cloned per 5 X 10(5) cells cultured. Colonies were present after 6 d of incubation reaching peak numbers between days 10 and 14 and slowly decreasing thereafter. Erythropoietin in concentrations of up to 4 U/ml failed to augment colony numbers. Also failing to enhance megakaryocyte colony plating efficiency were media containing burst-promoting activity and colony-stimulating activity. A medium conditioned by human embryonic kidney cells, which has been previously demonstrated to contain thrombopoietin, also had no effect on megakaryocyte colony numbers. In contrast, sera from three patients with severe aplastic anemia produced significant enhancement of CFU-M-derived colony formation in vitro. Both the number of megakaryocyte colonies present and the number of megakaryocytes per colony were increased in proportion to the final concentration of aplastic anemia serum. In the presence of 10% aplastic anemia serum, cultured megakaryocyte colony numbers were linear with respect to the number of bone marrow mononuclear cells plated suggesting a clonal origin of each of the colonies. This in vitro assay for bone marrow CFU-M is a reliable means by which to study the regulation of human megakaryocytopoiesis. Initial data suggest that megakaryocyte production is stimulated by a factor detectable in aplastic anemia serum that may be distinct from other known hematopoietic stem cell regulators.
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PMID:Regulation of human megakaryocytopoiesis. An in vito analysis. 727 69

Granulocyte--colony stimulating factor (G-CSF, filgrastim) is a glycoprotein hormone of the hematopoietin family that primarily influences the proliferation and differentiation of neutrophilic granulocytic precursors. As with all glyco-protein hormones, G-CSF interacts with target cells by binding to specific cell-surface receptors. It stimulates proliferation, differentiation and activation of cells of the neutrophil--granulocyte lineage and has been investigated as therapy for patients with various neutropenic conditions. A major use for recombinant G-CSF therapy will be in ameliorating the neutropenia which follows cytoreductive chemotherapy. The increase in neutrophils produced by this factor render it a useful treatment for conditions such as congenital, acquired and cyclic neutropenias. It may be an effective therapy in myelodysplasia and aplastic anaemia. G-CSF is also useful in accelerating the recovery of transplanted bone marrow in patients with leukaemia, lymphoma and solid tumors. G-CSF is well tolerated. The most frequently reported adverse effect is mild to moderate bone pain.
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PMID:[Biological properties and clinical application of filgrastim (G-CSF)]. 750 84

CD52 is a phosphatidylinositolglycan (PIG)-anchored glycoprotein (PIG-AP) expressed on normal T and B lymphocytes, monocytes, and the majority of B-cell non-Hodgkin lymphomas. We observed the emergence of CD52- T cells in 3 patients after intravenous treatment with the humanized anti-CD52 monoclonal antibody Campath-1H for refractory B-cell lymphoma and could identify the underlaying mechanism. In addition to the absence of CD52, the PIG-AP CD48 and CD59 were not detectable on the CD52- T cells in 2 patients. PIG-AP-deficient T-cell clones from both patients were established. Analysis of the mRNA of the PIG-A gene showed an abnormal size in the T-cell clones from 1 of these patients, suggesting that a mutation in the PIG-A gene was the cause of the expression defect of PIG-AP. An escape from an immune attack directed against PIG-AP+ hematopoiesis has been hypothesized as the cause of the occurrence of PIG-AP-deficient cells in paroxysmal nocturnal hemoglobinuria (PNH) and aplastic anemia. Our results support the hypothesis that an attack against the PIG-AP CD52 might lead to the expansion of a PIG-anchor-deficient cell population with the phenotypic and molecular characteristics of PNH cells.
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PMID:Emergence of CD52-, phosphatidylinositolglycan-anchor-deficient T lymphocytes after in vivo application of Campath-1H for refractory B-cell non-Hodgkin lymphoma. 763 56

A new culture and quantitation system has been established for growth of megakaryocyte-lineage cells from human progenitor cells. CD34+ progenitor cells were enriched from umbilical cord blood using an avidin-biotin immunoadsorption process. These cells were preincubated in bulk liquid culture for 3 to 4 days in the presence of the growth factors interleukin-3 (IL-3) and IL-6. The cells were then washed and seeded at 5000 cells/well in 96-well plates that contained a variety of test samples. The plates were incubated for 7 days, and the cells were then washed, transferred to ELISA plates, and fixed. Megakaryocyte growth was determined by an ELISA for the platelet glycoprotein (GP) IIb/IIIa, an abundant membrane protein found on cells committed to the megakaryocyte lineage. The growth factor IL-3 was found to produce a very strong signal in this assay. The addition of granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, stem cell factor (SCF), or leukemia inhibitory factor (LIF) to low levels of IL-3 also stimulated megakaryocyte growth, as measured by IIb/IIIa expression. Plasma from patients with aplastic anemia was also stimulatory in this assay, and showed marked synergy with IL-3. This progenitor cell culture system, due to its judicious use of progenitor cells and an automated, 96-well quantitation method, allows for screening large numbers of test samples and multiple combinations and concentrations of growth factors.
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PMID:A new culture and quantitation system for megakaryocyte growth using cord blood CD34+ cells and the GPIIb/IIIa marker. 769 35


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