Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Erythropoietin titers, measured by bioassay of plasma extracts in hypertransfused mice, were determined in 162 patients with absolute erythrocytosis, and the results were correlated with the clinical diagnosis. Fifty-two patients met the diagnostic criteria for polycythemia vera, and all had low or nonmeasurable erythropoietin titers. Of the remaining 110 patients, 62 were suspected clinically as having secondary polycythemia. However, 15 had low erythropoietin titers, casting doubt on the accuracy of the clinical diagnosis. The pathogenesis of the erythrocytosis in the last 48 patients was unknown, and they were designated clinically as having pure erythrocytosis. However, in 20, the erythropoietin titers were increased, and in 28, the titers were low, suggesting that they belonged to at least two different groups. Using erythropoietin titers in the classification of absolute erythrocytosis, the first group should be added to the category of patients with secondary polycythemia as a subgroup with disease due to idiopathic overproduction of erythropoietin (hypererythropoietinemia or essential erythrocytosis). The second group should be added as a subgroup of patients with primary polycythemia under the term erythremia.
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PMID:Pure erythrocytosis classified according to erythropoietin titers. 669 62

Erythropoietic progenitors from peripheral blood of normal individuals or patients with polycythemia vera (PV) were cultured in methylcellulose medium containing 2.5 U/ml of erythropoietin (Ep). After 7-9 days, colonies considered to be early stage large bursts were individually removed, resuspended in a small volume of fresh methylcellulose medium, and then divided between 2 dishes. To one of these secondary cultures, sufficient Ep was added to bring the concentration of Ep up to approximately 3 U/ml. To the other was added an equal volume of medium but no Ep. The final concentration of Ep in these cultures was determined to be less than 0.01 U/ml. Nine days later, both types of secondary cultures were scored for the presence of colonies containing 8 or more hemoglobinized erythroblasts. Of 90 primary colonies from 3 normal individuals assessed in this way, 59 gave secondary erythroid colonies in the high Ep cultures, while none gave secondary erythroid colonies in the low Ep cultures. Additional control experiments in which primary colonies from normal individuals were divided into duplicate high Ep cultures showed that on average, the procedure used divided primary colonies equally. Of 109 primary colonies from 5 PV patients that yielded secondary erythroid colonies in the high Ep cultures, 21 yielded no secondary erythroid colonies in the low Ep cultures. The other 88 yielded erythroid colonies in both, but the secondary colonies in the low Ep cultures were consistently smaller in size and significantly fewer in number. Similar results were obtained when primary colonies were generated in cultures to which no Ep was added. These findings indicate that primitive BFU-E in patients with PV can be subdivided into 2 populations: a minor population restricted to the production of erythroid colony-forming cells (Ep-dependent progenitors) that require Ep for their detection, and a major population that is not restricted in this way. In addition, these experiments show that most of the primitive BFU-E that generate Ep-independent progenitors also produce significant numbers of cells that are Ep-dependent.
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PMID:Individual BFU-E in polycythemia vera produce both erythropoietin dependent and independent progeny. 683 Oct 48

Peripheral blood mononuclear cells from five patients with polycythemia vera (P. vera) and three with other polycythemias were cultured in a methylcellulose system. Colony-forming unit-erythroid (CFU-E) colonies appeared after seven days in the absence of added erythropoietin (Ep) in all P. vera cultures. A pattern of growth similar to the one seen for P. vera patients occurred in the culture from a patient in whom that disease was suspected. In the cultures from two of the patients with other polycythemias, erythroid colonies did not appear even in the presence of Ep. These findings emphasize the potential value of culturing peripheral blood for CFU-E colonies in diagnosing polycythemia vera.
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PMID:Diagnostic use of CFU-E formation from peripheral blood in polycythemia vera. 683 14

A patient with Ph1-positive chronic myelogenous leukemia (CML) who entered an erythroblastic transformation prior to the development of a typical myeloblastic crisis is described. In vitro methylcellulose cultures obtained at the time of erythroblastic transformation revealed that the erythroid progenitors were responsive to erythropoietin. Thus, similar to the findings in polycythemia vera, the erythroid progenitors in this case of erythroblastic transformation of CML retained responsiveness to erythropoietin in vitro.
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PMID:In vitro response to erythropoietin in erythroblastic transformation of chronic myelogenous leukemia. 693 16

Human pluripotent hemopoietic progenitors (CFU-GEMM) from mixed colonies when cultured in methylcellulose or agar in the presence of erythropoietin and PHA-LCM. The observed frequency is low and varies for different individuals between 0 and 4 mixed colonies/O5 mononuclear cells. CFU-GEMM do not adhere to glass or plastic surfaces; their density is less than 1.077 g/ml, and their sedimentation velocity profile peaks at 4.5 mm/h. They do not form rosettes with sheep red blood cells. These physical parameters can be used preparatively to enrich for CFU-GEMM to facilitate assessment of their biological properties such as cycle state analysis and measurement of self-renewal capacity. Preliminary information suggests that some CFU-GEMM are capable of self-replication. Cycle state data are available for a larger number of patients with various clinical conditions. CFU-GEMM were found to be quiescent under steady-state conditions. They proliferate actively during bone marrow regeneration and in stem cell disorders like Polycythemia rubra vera or CML. These changes in cycle state activity were not reflected in numerical alterations of CFU-GEMM. It was thus concluded that the assay may be used more meaningfully to assess biological properties of human pluripotent progenitors rather than their frequency.
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PMID:Properties of human pluripotent hemopoietic progenitors. 693 20

The principal function of erythrocytes is the transport of oxygen. Erythropoiesis proceeds at a rate consistent with the demand for oxygen-carrying capacity, and the major regulator of erythrocyte production is erythropoietin. Erythropoietin is produced primarily by the kidney under control of a tissue oxygenation sensor. The recently developed erythropoietin radioimmunoassay should provide a clinically useful tool. Erythrocytosis is a pathologic state characterized by an elevated erythrocyte mass, which may result from increased proliferation of erythroid progenitors due to an intrinsic cellular defect or in response to extrinsic signals. Secondary erythrocytosis results from either physiologically appropriate compensation for inadequate tissue oxygenation or from inappropriate stimulation of erythropoiesis. Erythrocytosis increases oxygen-carrying capacity of the blood, but at high hematocrit levels increased blood viscosity may result in decreased tissue oxygen delivery. Polycythemia vera is a hematopoietic stem cell disease of clonal origin. Initial results from the Polycythemia Rubra Study Group suggest that therapy with chlorambucil is associated with an unacceptably high risk for development of acute leukemia, and 32P is preferred for situations in which phlebotomy alone is insufficient.
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PMID:Polycythemia: mechanisms and management. 701 37

Previous in vitro studies on committed hematopoietic progenitors have suggested that polycythemia vera (PV) is a clonal disorder arising in a pluripotential hematopoietic stem cell. In this study, recently developed technics for clonal assay of a human multipotential progenitor cell (CFU-GEMM) were used to assess the functional characteristics of CFU-GEMM in 19 PV patients. These studies showed: (a) increased numbers of detectable CFU-GEMM in blood and bone marrow samples of PV patients as compared with normals (P less than 0.002 and P less than 0.02, respectively); (b) erythropoietic differentiation of PV CFU-GEMM without exogenous erythropoietin (Ep) in culture (in marked contrast to CFU-GEMM of both normals and subjects with secondary erythrocytosis which require exogenous Ep for terminal hemoglobinization of their erythroid component), a property shown by experiments with an anti-Ep antiserum to be related to increased sensitivity of PV CFU-GEMM to Ep; (c) increased megakaryocyte formation by PV CFU-GEMM as compared with normals (P less than 0.025); and (d) a linear relationship, extrapolating to the origin, between CFU-GEMM detected and cells cultured. These studies demonstrate that at least two clinical features of PV, increased erythropoiesis and megakaryocytopoiesis, are reflected in corresponding functional characteristics of PV CFU-GEMM, and provide direct evidence of distinctive pluripotential stem cell activity in this disorder.
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PMID:In vitro studies of human pluripotential hematopoietic progenitors in polycythemia vera. Direct evidence of stem cell involvement. 706 49

Peripheral blood mononuclear cells from a patient with polycythemia vera were cultured in a methylcellulose system employing human serum. Electron microscopy documented the appearance of mixed colonies containing lymphocytes, granulocytes, megakaryocytes, and erythrocytes. In vitro culture characteristics were similar to those seen for other patients with polycythemia ver, ie, colonies grew in the absence of added erythropoietin or other pathway-specific regulators. Plating efficiency was linearly related to the number of cells plated, which supports the concept that each colony arose from a single cell. The appearance of mixed myeloid-lymphoid colonies points to the existence of a primitive stem cell capable of giving rise to multiple hematopoietic cell lines.
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PMID:Mixed myeloid-Lymphoid colonies in a patient with polycythemia vera. 711 54

Erythrocytosis was seen in two men during maintenance hemodialysis therapy for end-stage renal disease secondary to apparent chronic glomerulonephritis. Nonrenal causes of erythrocytosis such as polycythemia vera, chronic hypoxemia, high-oxygen affinity hemoglobin, and hepatoma were excluded by appropriate clinical studies. A computed tomographic scan of the abdomen showed numerous renal cysts in each patient consistent with acquired cystic disease of end-stage kidneys. Peripheral serum erythropoietin levels were elevated as measured by sensitive radioimmunoassay. The findings suggest that the erythrocytosis is caused by an erythropoietic mechanism related to the diseased kidneys. A review of the literature failed to show previous reports of this clinical association.
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PMID:Erythrocytosis in patients on long-term hemodialysis. 713 32

An RIA for Ep has been developed that is highly sensitive and specific. A homogeneous Ep preparation was labeled with 125 I by the chloramine-T method to a specific activity of 90 to 136 micro Ci/microgram and immunoreactivity of 80%. Ep antiserum, which was produced to a human urinary Ep preparation (80 U/mg of protein), was adsorbed with normal human urinary and serum proteins without any loss in sensitivity of the RIA to increase the specificity of the assay. A good correlation was seen between the RIA and the exhypoxic polycythemic mouse assay (corr. coef. 0.967; slope 1.05 and "y" intercept 0.75). Ep titers in sera from 175 hematologically normal human subjects exhibited a normal frequency distribution and ranged between 5.8 and 36.6 mU/ml with a mean of 14.9 +/- 4.7 (S.D.) and median of 14.3 Serum Ep titers were markedly elevated in seven patients with aplastic anemia and one patient with pure red cell aplasia (1350 to 20,640 mU/ml) and were lower than normal in two patients with polycythemia vera (8.1 and 9.4 mU/ml). The serum Ep titers in a prenephrectomy patient with chronic glomerulonephritis (32.1 mU/ml) decreased to below normal levels (9.04 mU/ml) after nephrectomy. The cord serum erythropoietin titers in 10 IDM [90.82 +/- 134.1 (S.D.) mu/ml] returned to values within the normal range (13.86 +/- 5.55) on day 3 after birth, suggesting the utility of the RIA in elucidating the role of hypoxia and/or insulin in increased erythropoiesis in IDM. The serum Ep titers in patients with anemias and polycythemias were compared to those of normal human subjects and agreed well with pathophysiologic mechanisms of these hemopoietic disorders, confirming the validity of the RIA.
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PMID:A radioimmunoassay for erythropoietin: serum levels in normal human subjects and patients with hemopoietic disorders. 714 88


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