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Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the in vitro culture growth of bone marrow and blood erythroid progenitors and serum erythropoietin (EPO) levels by radioimmunoassay in 24 patients with idiopathic erythrocytosis (IE). All patients had an increased red blood cell (RBC) mass and lacked a cause of secondary polycythemia, but did not fulfill the diagnostic criteria of polycythemia vera (PV). Marrow and blood cultures were obtained simultaneously; the results of endogenous (EPO-independent) erythroid colony (EEC) growth were parallel in both cultures. EECs were present in five patients, all of them developed PV 3 to 48 months later. The EEC number did not correlate with the time to the progression of PV. In contrast, none of the 19 EEC-negative patients had PV evolution during a median follow-up period of 38 months. Three of the five IE patients in whom EECs formed displayed vascular complications during their clinical course compared with three of 19 patients who did not have EEC. The serum EPO levels were variable: low in five, normal in 14, and high in five patients. Serial measurements of serum EPO levels in three of five patients who had high initial levels showed persistently elevated values; the underlying cause of the increased EPO production could not be defined during a follow-up period of more than 36 months. Of the five patients who subsequently developed PV, two had low serum EPO levels and three had normal values at initial evaluation. Serum EPO levels did not correlate with the occurrence of thrombotic complications. Our results show that serum EPO levels have limited value in determining the underlying cause of IE and cannot predict the clinical course of patients with IE, whereas the assessment of EEC in bone marrow or blood can identify IE patients who will have PV evolution.
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PMID:Prediction of clinical course in patients with idiopathic erythrocytosis by endogenous erythroid colony assay but not by serum erythropoietin levels. 913 Oct 2

The present study revises the criteria of the Polycythemia Vera Group (PVSG) for the diagnoses of essential thrombocythemia (ET) and polycythemia vera (PV) in view of accumulating data on in vitro cultures of hematopoietic progenitors and by adding histopathology from bone marrow biopsies. The majority of ET patients show spontaneous megakaryocyte or erythroid growth or both, but in about 35% the growth pattern is normal. So far none of the patients with reactive thrombocytosis have shown either spontaneous megakaryocyte or erythroid colony growth. Virtually all PV patients show spontaneous or endogenous erythroid colony (EEC) formation, whereas patients with secondary erythrocytosis and healthy controls do not show any erythroid colony growth in the absence of erythropoietin (EPO). Some rare patients with a disorder other than a myeloproliferative disease (MPD) may show spontaneous growth of erythroid colonies caused by a mutation in the EPO receptor. Megakaryocytes in bone marrow smears and biopsy material from ET and PV patients are typically increased in number and size. Enlarged megakaryocytes with mature cytoplasm and multilobulated nuclei and the tendency of these megakaryocytes to cluster in a normal or slightly increased cellular bone marrow represent the diagnostic hallmark of ET. Increase and clustering of enlarged, mature, and pleiomorphic megakaryocytes in a moderate to marked hypercellular bone marrow with hyperplasia of dilated sinuses is the diagnostic feature of untreated PV. In reactive thrombocytosis and secondary erythrocytosis the size and morphology of megakaryocytes remain normal and there is no tendency of the megakaryocytes to cluster. Both spontaneous EEC and histopathology of bone marrow biopsies appear to offer specific clues to the diagnosis of overt and latent ET or PV and have the potential to differentiate ET from reactive thrombocytosis and PV from secondary erythrocytosis. Moreover, bone marrow histopathology has the diagnostic power to distinguish and to stage the various MPDs without regard to clinical and laboratory data.
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PMID:Proposal for revised diagnostic criteria of essential thrombocythemia and polycythemia vera by the Thrombocythemia Vera Study Group. 926 50

Primary polycythemias are caused by an acquired or inborn mutation affecting hematopoietic/erythroid progenitors that results in an abnormal response to hematopoietic cytokines. Primary familial and congenital polycythemia (PFCP; also known as familial erythrocytosis) is characterized by elevated red blood cell mass, low serum erythropoietin (EPO) level, normal oxygen affinity of hemoglobin, and typically autosomal dominant inheritance. In this study we screened for mutations in the cytoplasmic domain of the EPO receptor (EPOR; exons 7 and 8 of the EPOR gene) in 27 unrelated subjects with primary or unidentified polycythemia. Two new EPOR mutations were found, which lead to truncation of the EPOR similarly to previously described mutations in PFCP subjects. The first is a 7-bp deletion (del5985-5991) found in a Caucasian family from Ohio. The second mutation (5967insT) was found in a Caucasian family from the Czech Republic. In both cases the EPO dose responses of the erythroid progenitors of the affected subjects were examined to confirm the diagnosis of PFCP. In one of these families, the in vitro behavior of erythroid progenitors in serum-containing cultures without the addition of EPO mimicked the behavior of polycythemia vera progenitors; however, we show that antibodies against either EPO or the EPOR distinguish the in vitro growth abnormality of polycythemia vera erythroid progenitors from that seen in this particular PFCP family. We conclude that PFCP is a disorder that appears to be associated in some families with EPOR mutations. So far, most of the described EPOR mutations (6 out of 8) associated with PFCP result in an absence of the C-terminal negative regulatory domain of the receptor.
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PMID:Two new EPO receptor mutations: truncated EPO receptors are most frequently associated with primary familial and congenital polycythemias. 929 43

Essential thrombocythemia (ET) and polycythemia vera (PV) are chronic clonal myeloid disorders that originate from the multipotential hematopoietic stem cell. They are characterized, respectively, by excessive thrombocytosis and erythrocytosis, a high incidence of thrombohemorrhagic events, vasomotor symptoms, and an inherent tendency to undergo leukemic transformation. Current standard therapies to control the excess accumulation of myeloid cells and to provide symptomatic relief carry either a persistent risk of thrombosis, as in the case of phlebotomy, or, in the case of hydroxyurea, the potential for inducing leukemia. None alter the natural history of these diseases. Interferon-alpha has been shown to have potent antiproliferative effects on the hematopoietic stem cells and bone marrow fibroblasts and, as a result, has received much attention as a therapeutic agent for chronic myeloproliferative disorders. The ability of interferon-alpha to induce hematologic and cytogenetic remission in chronic phase chronic granulocytic leukemia has further increased interest in this agent. Interferon-alpha has shown therapeutic activity in PV and ET, as demonstrated in multiple small studies and single-arm trials reviewed in this article. Reported beneficial effects include the ability to control excessive erythrocytosis and thrombocytosis and such disease-related features as vasomotor symptoms, pruritus, and splenomegaly. Recent reports of cytogenetic remission and reversal of bone marrow fibrosis after interferon therapy are of interest. Advantages over current therapeutic standards include lack of known leukemogenic and teratogenic effects and the potential to alter the underlying course of disease. Nevertheless, none of the information available allows definite therapeutic recommendations for the use of interferon-alpha in PV or ET. The available data support the need for randomized controlled trials comparing interferon-alpha with standard therapy.
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PMID:Interferon-alpha therapy in polycythemia vera and essential thrombocythemia. 938 5

Chronic obstructive pulmonary disease (COPD) can be accompanied by compensatory secondary erythrocytosis. However, the exact prevalence of secondary erythrocytosis in COPD is unknown. Although diagnostic criteria for polycythemia vera versus secondary erythrocytosis are mutually exclusive, we describe here the coexistence of polycythemia vera and COPD in the same patient.
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PMID:Erythrocytosis in a patient with chronic obstructive pulmonary disease. 954 29

We present an 86-years-old woman's case with paralysis in her left hand of abrupt apparition, accompanied by arterial hypertension and dizziness. The investigation revealed erythrocytosis, leukocytosis, thrombocytosis, with normal arterial O2 saturation (O2 SAT), increased of his red cell volume and blood viscosity. The polycythaemia vera (PV) was diagnose and the paralysis disappeared, when 24 hours before a phlebotomy was practiced, and the function was recovered by the hand. We analysed the presents diagnostics criteria of the disease defined by Polycythaemia Vera Study Group (PVSG). The different treatments for PV are discussed; in addition to venesection, conventional treatment include chemotherapy with hydroxyurea and pipobroman, as well as the erythropheresis, -interferon and aspirin. All of the treatments are associated with complications; thrombotic in the case of phlebotomy; malignancies and gastrointestinal bleeding in the case of myelosuppressive treatments and aspirin. We think the optimal treatment for PV is a judicious combination of the available alternatives, depending on the phase of the disease, and the age of the patient.
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PMID:[Primary polycythaemia vera in the elderly]. 958 Jan 77

Polycythemia vera (PV) is a clonal stem cell disorder characterized by excessive erythrocyte production, resulting in absolute erythrocytosis. No specific structural chromosomal abnormalities have been reported in PV to date. We have observed two cases of PV with an extra i(9)(p10) as the sole anomaly, and FISH analysis using a 9p-specific chromosome microdissection probe showed that two other PV patients previously identified as having an add(18p) and an add(1p) as the primary changes actually carried a der(18)t(9;18)(p12;p11.2) and a der(1)t(1;9)(p12;p12), respectively. The same FISH assay was employed to evaluate domain signals on interphase cells of 15 more cases of PV with normal karyotypes and five normal controls. Two patients were observed with a significant increase in the percentage of cells with three domain signals. Our results strongly indicate that an additional i(9)(p10) is a new and recurrent primary chromosome anomaly in PV, and, in consideration of trisomy 9 being one of the most common anomalies in PV, amplification of a gene or genes on 9p, but not on 9q, may play a crucial role in the pathogenesis of PV.
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PMID:Gain of 9p in the pathogenesis of polycythemia vera. 966 70

Previously we described activating mutations of hbetac, the common signaling subunit of the receptors for the hematopoietic and inflammatory cytokines, GM-CSF, IL-3, and IL-5. The activated mutant, hbetacFIDelta, is able to confer growth factor-independent proliferation on the murine myeloid cell line FDC-P1, and on primary committed myeloid progenitors. We have used this activating mutation to study the effects of chronic cytokine receptor stimulation. Transgenic mice were produced carrying the hbetacFIDelta cDNA linked to the constitutive promoter derived from the phosphoglycerate kinase gene, PGK-1. Transgene expression was demonstrated in several tissues and functional activity of the mutant receptor was confirmed in hematopoietic tissues by the presence of granulocyte macrophage and macrophage colony-forming cells (CFU-GM and CFU-M) in the absence of added cytokines. All transgenic mice display a myeloproliferative disorder characterized by splenomegaly, erythrocytosis, and granulocytic and megakaryocytic hyperplasia. This disorder resembles the human disease polycythemia vera, suggesting that activating mutations in hbetac may play a role in the pathogenesis of this myeloproliferative disorder. In addition, these transgenic mice develop a sporadic, progressive neurological disease and display bilateral, symmetrical foci of necrosis in the white matter of brain stem associated with an accumulation of macrophages. Thus, chronic hbetac activation has the potential to contribute to pathological events in the central nervous system.
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PMID:Dysregulated hematopoiesis and a progressive neurological disorder induced by expression of an activated form of the human common beta chain in transgenic mice. 983 20

The chronic myeloid disorders are collectively characterized by a stem cell origin of the clonal process and a variable tendency to undergo indigenous disease transformation and leukemic conversion. Classification of the chronic myeloid processes is based primarily on the presence or absence of the Philadelphia chromosome (bcr-abl translocation) and secondarily on the morphologic picture of the bone marrow in conjunction with the clinical manifestation. Essential thrombocythemia (ET), polycythemia vera (PV), and agnogenic myeloid metaplasia (AMM) constitute the classical group of bcr-abl negative chronic myeloproliferative disorders. PV is characterized by a clonal increase in red blood cell mass, AMM by bone marrow fibrosis, and ET by thrombocytosis. Most of these features, however, are not diagnostically specific, and secondary causes of erythrocytosis, thrombocytosis, and bone marrow fibrosis must be excluded. Treatment may be deferred or limited to phlebotomy alone in some patients with ET or PV, respectively. In contrast, thrombosisprone patients with PV or ET require drug therapy, and new platelet-lowering agents are increasingly being used. In this article, current diagnostic and therapeutic issues of ET, PV, and AMM are discussed.
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PMID:The Philadelphia chromosome negative chronic myeloproliferative disorders: a practical overview. 1040 9

This review will discuss evidence for the role of the erythropoietin (Epo) receptor in the development of erythrocytosis and other hematological disorders. The possible causative role of mutations of other genes in the pathogenesis of idiopathic erythrocytosis will be considered. Polycythemia vera (PV) is a myeloproliferative disorder that is caused by an undefined stem cell abnormality, characterized by a significant erythrocytosis, leukocytosis, and thrombocytosis. However, erythrocytosis may arise from apparent (or relative) polycythemia in which the hematocrit is raised due to a low plasma volume. In such cases the red cell mass is normal. A group of disorders with increased red cell mass caused by stimulation of erythrocyte production is known as secondary polycythemia. Investigation of such patients may reveal a congenital abnormality such as high affinity hemoglobin or an acquired abnormality caused, for example, by smoking, renal vascular impairment, or an Epo-producing tumor. Even after thorough examination there remains a cohort of patients for whom no definite cause for the erythrocytosis can be established. A careful clinical history may reveal whether this idiopathic erythrocytosis is likely to be congenital and/or familial, in which case the term "primary familial and congenital polycythemia" is sometimes applied. Access to a range of laboratory investigations may define the molecular pathophysiology. We will now discuss how this process can be investigated.
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PMID:Erythropoietin receptor and hematological disease. 988 6


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