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)

A 57-year-old male who had suffered from polycythemia vera (PV) and had been treated with pipobroman, carbazilquinon and busulfan for ten years presented with fever. CBC revealed anemia and thrombocytopenia without an increase of leukemic blasts (WBC, 7,700/microliters, RBC 294 x 10(4)/microliters, Hb 9.1 g/dl, Plt 1.5 x 10(4)/microliters). Bone marrow aspiration resulted in dry tap. Bone marrow biopsy showed hyperplastic marrow with fibrosis and no increase in leukemic blasts. Eleven days later the patient became leukemic and he died of DIC. Blast cells showed a high nucleo-cytoplasmic ratio, basophilic cytoplasm and cytoplasmic blebs. Cytochemical and immunophenotype analysis of the blast cells showed the following results; myeloperoxidase (-), chloroacetate esterase (-), Sudan black (-), acid phosphatase (+), acetate esterase (+), PAS (+), HLA-DR (+) and GPIIb/IIIa (+). Platelet peroxidase reaction on electron microscopy was positive in perinuclear spaces and endoplasmic reticulum. A diagnosis of megakaryoblastic transformation of PV was made. Although acute myelogenous leukemia has been shown to develop occasionally in the course of PV, acute megakaryoblastic leukemia with DIC following PV is a very rare condition.
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PMID:[Megakaryoblastic transformation associated with disseminated intravascular coagulation in the course of polycythemia vera: a case report]. 160 15

Megakaryocytes (MKs) from 40 patients with quantitative platelet disorders and 19 normal volunteers were analyzed by flow cytometry for size, fine cell internal structure and granularity, membrane expression of the glycoprotein (GP) IIb/IIIa complex, and for ploidy distribution. Analysis was performed on unfractionated minimally manipulated marrows obtained from routine bone marrow aspirates. MKs were labeled with a fluorescent lineage-specific monoclonal antibody to the GPIIb/IIIa complex followed by DNA staining with propidium iodide. Eight hundred to 3,000 MKs were analyzed in each sample. The modal ploidy distribution in normals was 16N, comprising about half of the megakaryocytic population, with 22.6% of the cells less than or equal to 8N and 22.0% greater than or equal to 32N. Twelve thrombocytopenic patients with decreased marrow MKs on biopsy (mean platelet count [MPC] 44,600/microliters) showed an increase in low ploidy cells with 53.2% less than or equal to 8N (P less than .01); cell size was reduced in three patients when compared to normal cells of identical ploidy (P less than .05). Eight thrombocytopenic patients with enhanced platelet destruction (with normal or increased MKs on biopsy and shortened platelet survival; MPC 41,400/microliters) showed an increased proportion of high ploidy cells greater than or equal to 32N to 39.2% (P less than .01). Increased cell size and granularity were found in four of these patients (P less than .05). Six patients with thrombocytopenia secondary to multiple mechanisms affecting both platelet production and destruction (MPC 66,700/microliters) showed no shift in ploidy. Four patients with primary thrombocytosis (two with thrombocythemia and two with polycythemia vera; MPC 822,500/microliters) showed a marked shift toward high ploidy cells with 42.3% greater than or equal to 32N and 7.6% greater than or equal to 64N cells (P less than .01). The shift was accompanied by a marked increase in cell size and granularity in the patients with thrombocythemia. Ten patients with thrombocytosis secondary to chronic blood loss, malignant or inflammatory disorders (MPC 714,000/microliters), showed variable distributions with four patients exhibiting a shift in ploidy to the right similar to that found in the patients with increased platelet destruction. Based upon the present data, flow cytometric ploidy distribution may be diagnostically useful in thrombocytopenic patients by discriminating between disorders of platelet production and destruction. (ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Flow cytometric analysis of megakaryocytes from patients with abnormal platelet counts. 275 35

Megakaryocytes are platelet forming cells and are characterized by polyploidization, a phenomenon by which nuclear division occurs without corresponding cytoplasmic separation. Among the markers allowing to identify megakaryocytes, glycoprotein (GP) IIIa with GPIb and GPIIb are the most important. Using GPIIIa as a marker to recognize megakaryocytes in the bone marrow, we have estimated GPIIIa expression by flow cytometry in megakaryocyte populations from normal individuals and from patients with chronic myelogenous leukemia, immune thrombocytopenic purpura or polycythemia vera. We showed that the expression of GPIIIa is decreasing during megakaryocyte polyploidization in normal and pathological situations.
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PMID:Human megakaryocyte polyploidization is associated with a decrease in GPIIIA expression. 1069 32

Polycythemia vera is a myeloproliferative disorder predisposing to thromboembolic and bleeding complications. We report the case of a patient with polyglobuly, leukocytosis, and thrombocytosis, who suffered from acute ST-segment elevation myocardial infarction due to thrombotic high-grade pre-stent stenosis two months after percutaneous coronary intervention for complex coronary one vessel disease. Following re-PTCA and stent implantation in conjunction with periinterventional GP IIb/IIIa antagonist treatment, the patient was initially symptom free for about two hours before rapidly developing signs of a hemorrhagic shock. An abdominal CT scan showed splenic rupture with massive intraabdominal hemorrhage as a consequence of secondary bleeding into multiple pre-existing splenic infarctions. The patient's condition stabilized after emergency splenectomy. Subsequent bone marrow biopsy revealed the presence of polycythemia vera. Post-operatively, the patient was treated with the anti-platelet agents aspirin and clopidogrel to prevent subacute stent thrombosis. Additionally, cyto-reductive therapy with hydroxyurea was initiated because of a further increase in the platelet count. In patients with polycythemia vera, the indication for treatment with GP IIb/IIIa antagonists should be carefully weighed against the potentially serious bleeding complications. Should treatment be established, a risk stratification using abdominal sonography and bleeding time testing is recommended, while during treatment red blood count, platelet count, coagulation tests, and hemodynamic parameters should be closely monitored.
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PMID:Splenic rupture complicating periinterventional glycoprotein IIb/IIIa antagonist therapy for myocardial infarction in polycythemia vera. 1574 43

Inherited and acquired tendency to the formation of clots represents an important cause of morbidity and mortality for ischemic events in young people (aged between 40 and 50 years) that is more and more frequently identified. The haemostasis' disorders may happen on the venous or arterial side. Arterial thrombus is a 'white' thrombus, also called temporary thrombus. It consists of aggregate platelets only. On the contrary, venous thrombus is 'red' or permanent thrombus composed of platelets, red cells and fibrin. The first is the result of platelets' adhesion or aggregation. Instead, the permanent thrombus derives from the coagulant factors successively acting on 'white' thrombus. The different pathogenesis justifies both the distinction between 'hypercoagulability' and 'thrombophilia' and the different treatments employed. Antiphospholipid antibody syndrome, polycythemia vera, atrial fibrillation-acquired hyperhomocysteinemia, diabetes mellitus and myeloproliferative disease are the most frequent causes of acquired hypercoagulable state, prevalently responsible for deep venous thrombosis. Among the inherited forms, congenital hyperhomocysteinemia, factor V Leiden mutation, proteins C and S deficiency and antithrombin mutation are included. These may induce both venous and arterial acute events. Hyperhomocysteinemia can be congenital and acquired and is more correctly named as 'thrombophilia' rather than 'hypercoagulability'. That happens because it involves the platelets' aggregation rather than the coagulant cascade. The optimal treatment of thrombophilias consists of oral (warfarin) or injectable (heparins) anticoagulants. Direct thrombin inhibitors, platelet glycoprotein IIb/IIIa antagonists, and tissue factor inhibitors also appear to be some attractive approaches. For acquired forms, treatments of their aetiologies must also be carried out. For acquired hyperhomocysteinemia, both antiplatelets' therapy (aspirin + clopidogrel) and new direct thrombin inhibitors (as dabigatran) could be considered. Finally, as secondary prevention of an arterial acute event (stroke, IMA or peripheral ischemia) due to hyperhomocysteinemia, lifetime dual antiplatelets' therapy should be used.
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PMID:Some considerations about the hypercoagulable states and their treatments. 2134 57

Using patients with polycythemia vera (PV) as an experimental model, we evaluated the impact of clot retraction (CR) and architecture of the clot on fibrinolysis. We studied the kinetics of clot retraction and the fibrinolysis rate in whole blood from 48 PV patients and 48 healthy controls. Measurements were performed before and after isovolemic eryhrocytapheresis (ECP). CR was measured by optical method. Clot lysis time (CLT) and maximum clot firmness (MCF) were measured by thromboelastometry in recalcified blood supplemented with t-PA and tissue factor. Compared with healthy controls, CR rate in PV patients was higher (0.0219 vs. 0.0138; p<0.001), the clot volume smaller and MCF elevated (64 vs. 58 mm). CR rate correlated with platelet count (r=0.546; p=0.001) but not with erythrocyte concentration (r=0.192; p>0.3). Compared with healthy controls, CLT in PV patients was significantly prolonged (158 min vs. 71 min). Fibrinolysis rate inversely correlated with CR rate (r=-0.566; p<0.001); MCF (r=-0.704; p<0.001) and platelet count (r=-0.461; p<0.001). As judged by confocal microscope, in comparison to healthy controls, clots formed in blood from PV patients demonstrated booth a distinctly higher degree of crosslinking and possessed thinner fibers. Altered CR, MCF and fibrinolysis speeds were not normalized following the ECP procedure. Tirofiban (a blocker of platelet GPIIb/IIIa receptors), unlike aspirin, normalized abnormal CR and fibrinolysis in blood from PV patients. Collectively, our data indicate that in PV patients, abnormal CR may result in formation of thrombi that are more resistant to fibrinolysis. ECP and aspirin failed to normalize platelet-related fibrinolysis resistance.
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PMID:Platelet-related fibrinolysis resistance in patients suffering from PV. Impact of clot retraction and isovolemic erythrocytapheresis. 2482 95