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)

The stem cell origination of the clonal process in chronic myeloproliferative disorders (CMPDs) is well established. In chronic myelogenous leukemia (CML), the primary genetic process has been characterized. However, current information regarding the mechanisms of phenotypic diversity among the CMPD and the downstream effects of the chromosomal translocation in CML remains inconclusive. In this report, the current understanding regarding erythrocytosis in polycythemia vera (PV), thrombocytosis in essential thrombocythemia (ET), bone marrow fibrosis (BMF) in agnogenic myeloid metaplasia (AMM), and the connection between the genetic alteration and cellular transformation in CML will be discussed.
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PMID:Pathogenetic mechanisms in chronic myeloproliferative disorders: polycythemia vera, essential thrombocythemia, agnogenic myeloid metaplasia, and chronic myelogenous leukemia. 993 May 50

The primary objective during the evaluation of erythrocytosis is to ascertain the presence or absence of polycythemia vera (PV). Because of prognostic and treatment differences, PV must be distinguished from relative polycythemia and secondary erythrocytosis. This distinction is currently accomplished through the laboratory measurement of red blood cell mass, plasma volume, and arterial oxygen saturation and determination of oxygen pressure at 50% hemoglobin saturation (P50). Furthermore, according to the Polycythemia Vera Study Group guidelines, the demonstration of an increased red blood cell mass is an absolute criterion for the diagnosis of PV. This article discusses the use of the serum erythropoietin level and endogenous erythroid colony assay as a potential alternative in the diagnosis of PV.
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PMID:Diagnosing polycythemia vera: a paradigm shift. 1006 55

Polycythemia vera (PV) is a myeloproliferative disorder characterized by thrombotic and, less often, bleeding complications. Many mechanisms have been advanced to explain the occurrence of these complications, none of them satisfactory. We examined a cohort of 27 patients with PV, secondary erythrocytosis, and essential thrombocythemia for coagulation and fibrinolytic parameters, including euglobulin lysis test, D-dimer, and alpha2 antiplasmin. Ten of the 27 patients developed one or more thrombotic complications during the study. We found no clinical correlation between the studied parameters and the complications. Three patients, one of each group, with elevated serum alpha2 antiplasmin levels, developed severe arterial or venous thromboses.
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PMID:Study of fibrinolytic parameters in different types of polycythemia. 1007 10

Erythrocytosis is not a feature of essential thrombocythemia (ET); this is the most important difference between ET and polycythemia vera (PV). Transformation of ET to PV has only rarely been described. We have reviewed the blood cell counts of 170 ET patients with a median follow-up of 63 months (range 11-313). Eleven of 170 patients (6.5%) developed erythrocytosis at a median of 29 months (range 12-138) after the diagnosis of ET. According to the present results, the development of erythrocytosis in patients with ET is not a rare phenomenon.
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PMID:Development of erythrocytosis in the course of essential thrombocythemia. 1039 Nov 2

Polycythaemia vera is a clonal myeloproliferative disorder mainly involving proliferation of the erythropoiesis. The symptoms are varied and usually unspecific. The most serious complications of the disease are a thrombotic tendency and myeloid metaplasia. Thromboses mainly (2/3) occur in the arterial and less often (1/3) in the venous system and are the most common cause of death. Criteria have been established for the diagnosis of polycythaemia vera which should be strictly observed in order to distinguish between this disease, spurious polycythaemia, essential thrombocythaemia and secondary erythrocytosis. The goal of treatment is the prevention of thromboembolic complications and of myeloid metaplasia. The initial treatment always consists of phlebotomies until a hematocrit < 45% is achieved. The decision regarding maintenance therapy is difficult. While hydroxyurea or radiophosphorus is the treatment of choice in older patients (> 70 years of age), it is more difficult to select the appropriate therapy for younger patients (< 60 years), since recent studies have indicated that hydroxyurea treatment might increase the risk of leukemia. Interferon is effective but its role in the treatment of polycythaemia vera has not been established.
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PMID:[Polycythaemia vera--diagnosis and therapy]. 1048 72

The term 'erythrocytosis' has advantages over 'polycythaemia' to describe patients with a raised haematocrit (PCV) and deserves to be more widely used. Measurement of red cell mass (RCM) and its relation to that expected for an individual's height and weight permits initial subdivision of erythrocytosis into absolute (increased RCM) or apparent normal RCM. Absolute erythrocytosis may be primary (intrinsically abnormal marrow erythropoiesis) or secondary (increased erythropoietin drive in response to pathological events outside the bone marrow). Both primary and secondary erythrocytosis may be either congenital or acquired. Idiopathic erythrocytosis is a third, probably heterogenous, group within the absolute erythrocytoses. Familial abnormalities of the erythropoietin receptor underlie the primary congenital subgroup. Polycythaemia vera (PV), the clonal myeloproliferative disorder, is so far, the only primary acquired disorder. Newer diagnostic investigations such as serum erythropoietin estimation, improved karyotypic analysis, in vitro culture of erythroid colonies and estimation of spleen size before splenomegaly is palpable, have permitted some modification of the traditional diagnostic criteria of polycythaemia vera. This may allow more confident diagnosis and, together with improved testing for causes of secondary erythrocytosis, may reduce the number of patients so far unsatisfactorily consigned to the idiopathic erythrocytosis group.
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PMID:The classification and diagnostic criteria of the erythrocytoses (polycythaemias) 1079 8

Differentiation of an elevated hemoglobin/hematocrit level warrants not only the determination of relevant laboratory values, including erythropoietin, but also an elaborate evaluation of bone marrow histopathology. Particularly in the initial stages of polycythemia vera (PV), when not all stringent clinical criteria are completely fulfilled, a more refined analysis of morphological features helps to distinguish autonomous (PV) from spurious or secondary erythrocytosis - polyglobuly (PG). PV is characterized by a panmyelosis, i.e., a trilinear proliferation of all cell lineages, whereas in PG erythropoiesis predominates. Megakaryopoiesis exerts a significant impact on differentiation, because in PV there is a conspicuous grouping associated with a strikingly expressed pleomorphous appearance. This peculiar feature implicates assemblies of small- to medium-sized megakaryocytes lying adjacent to giant cells with extensively lobulated, staghorn-like nuclei. A further discriminating parameter is presented by the interstitial lesions frequently occurring in PG. These, according to the usually underlying inflammatory cause (chronic bronchitis-recurrent bronchopneumonias), include iron-laden macrophages, a prominent perivascular plasmacytosis, phagocytosis of cell debris by histiocytic reticular cells and often an in- crease in the number of eosinophils. Comparable findings are not, or only to a minor ex-tent, detectable in PV. In conclusion, by regarding hematopoiesis and the myeloid stroma initial stages of PV may be definitively distinguished from PG.
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PMID:[ Polyglobuly versus polycythemia vera]. 1066 66

Polycythemia vera (PV) is a clonal stem cell disorder characterized by hyperproliferation of the erythroid, myeloid, and megakaryocytic lineages. Although it has been shown that progenitor cells of patients with PV are hypersensitive to several growth factors, the molecular pathogenesis of this disease remains unknown. To investigate the molecular defects underlying PV, we used subtractive hybridization to isolate complementary DNAs (cDNAs) differentially expressed in patients with PV versus normal controls. We isolated a novel gene, subsequently named PRV-1, which is highly expressed in granulocytes from patients with PV (n = 19), but not detectable in normal control granulocytes (n = 21). Moreover, PRV-1 is not expressed in mononuclear cells from patients with chronic myelogenous leukemia (n = 4) or acute myelogenous leukemia (n = 5) or in granulocytes from patients with essential thrombocythemia (n = 4) or secondary erythrocytosis (n = 4). Northern blot analysis showed that PRV-1 is highly expressed in normal human bone marrow and to a much lesser degree in fetal liver. It is not expressed in a variety of other tissues tested. Although PRV-1 is not expressed in resting granulocytes from normal controls, stimulation of these cells with granulocyte colony-stimulating factor induces PRV-1 expression. The PRV-1 cDNA encodes an open reading frame of 437 amino acids, which contains a signal peptide at the N-terminus and a hydrophobic segment at the C-terminus. In addition, PRV-1 contains 2 cysteine-rich domains homologous to those found in the uPAR/Ly6/CD59/snake toxin-receptor superfamily. We therefore propose that PRV-1 represents a novel hematopoietic receptor. (Blood. 2000;95:2569-2576)
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PMID:Cloning of PRV-1, a novel member of the uPAR receptor superfamily, which is overexpressed in polycythemia rubra vera. 1549 66

Therapeutic erythrocytapheresis (TEA) has been used in different diseases such as polycythemia vera (PV), secondary erythrocytosis or hemochromatosis as a process of the less cumbersome but more expensive phlebotomy. TEA is preferred in emergency conditions such as thrombocytosis or in conditions such as porphyria cutanea tarda (PCT) or erythropoietic porphyria when plasma exchange (PEX) is often combined with TEA to reduce extracellular levels of uroporphyrin which contribute to plasma hyperviscosity. TEA is often combined with drug therapy that varies from etoposide in PV to EPO and desferoxamine which are used to mobilize and reduce iron stores in hemochromatosis. Benefits from this combination may be more long lasting than expected. Nonetheless for TEA, there is no standard protocol and, clinical experience with this therapy remains highly anecdotal. Therapeutic red cell-exchange (TREX) has been used with much interest over the years, starting with the management of hemolytic disease of the newborn and later used to correct severe anemia in thalassemia patients thereby preventing iron overload. It has also been used for the management of complications of sickle cell disease such as priapism, chest syndrome, stroke, retinal, bone, splenic and hepatic infarction or in preparation for surgery by reducing HbS to less than 30%. Automated apheresis has also favored the use of TREX in conditions such as paroxysmal nocturnal hemoglobinuria and aniline poisoning, arsenic poisoning, Na chlorate intoxications and CO intoxications, hemoglobinopathies, autoimmune hemolytic anemia, reactions due to ABO incompatibility, in preparation for ABO incompatible bone marrow transplantation or for preventing anti-D immunization after the transfusion of D(+) cells to D(-) recipients. Another field of application has been in the emergency management of intraerythrocytic parasite infections such as malaria and babesiosis. Application of TREX may be wide but its real use remains limited. In our personal experience, in 16 years, only 167 TREX procedures have been carried out in a total of 13,747 therapeutic procedures. This represents only 1.21% of the total.
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PMID:Clinical application of therapeutic erythrocytapheresis (TEA). 1083 21

Recent studies have shown decreased megakaryocyte expression of the thrombopoietin receptor (c-mpl) in patients with polycythemia vera (PV) but not in those with reactive erythrocytosis. We examined the diagnostic utility of this observation in 22 patients with PV, 7 patients with secondary erythrocytosis (SE), and 10 normal controls. Commercial antibodies against c-mpl were used with standard immunoperoxidase methods. Megakaryocyte c-mpl staining intensity was uniformly moderate-to-strong in the healthy controls and in all the patients with SE. In contrast, staining intensity in 9 patients with PV (41%) was uniformly weak. Furthermore, in 12 of the remaining 13 patients with PV, the c-mpl staining pattern in each case was heterogeneous and was associated with weak staining intensity in more than 20% of the megakaryocyte population. These preliminary data suggest that c-mpl immunostains may complement bone marrow histopathology in distinguishing PV from nonclonal causes of erythrocytosis. (Blood. 2000;96:771-772)
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PMID:Immunohistochemical staining for megakaryocyte c-mpl may complement morphologic distinction between polycythemia vera and secondary erythrocytosis. 1136 62


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