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)

This study reviewed the clinical and hematologic characteristics of 161 patients with polycythemia vera treated with myelosuppressive agents, with or without antiaggregating platelet therapy, in order to determine the features associated with a risk of hemorrhagic or thrombotic complications. At presentation, 7 patients (4.3%) showed hemorrhages and 36 (22%) complained of thrombotic events. None of the evaluated clinical and hematologic parameters was significantly related to hemorrhagic or thrombotic presentation. During the clinical course, four of 107 patients (3.7%) experienced hemorrhagic complications and 34/107 patients (28%) complained of occlusive events, which accounted for 30% of total deaths. Among the clinical and hematologic presenting features, only age over 60 yrs could be identified as an unfavorable prognostic factor for the occurrence of thromboembolic episodes. Marked thrombocytosis, a high packed cell volume (PCV) and the thrombotic onset were not significantly related to the thrombotic risk. Platelet count and PCV at the time of the occlusive episode did not correlate with the clinical event; however, inadequate control of the proliferative disease seemed to increase the thrombotic tendency. Antiaggregating drugs, although unable to avoid thrombosis in our experience, might be safely associated with the myelosuppressive therapy, particularly in selected patients.
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PMID:Hemorrhagic and thrombotic complications in polycythemia vera. A clinical study. 249 82

Essential thrombocythaemia (ET) is a rare clonal myeloproliferative disorder characterized by a persistent increase in platelet count. The commonly used criteria for the diagnosis, except for the level of the increase in platelet count, are usually those fixed by the Polycythemia Vera Study Group. The average age of onset is around 60 years, both sexes being affected. The symptoms frequently present at diagnosis are related to microcirculatory disturbances (palms, soles, fingers). Neurological symptoms are often observed. Thrombotic complications of the large vessels are less frequent. Haemorrhagic problems are present in about 30% of patients. Bleeding time is normal in most cases, whereas platelet aggregation abnormalities are frequently found. Nil adrenaline aggregation is the most discriminative test. The clinical course is characterized by long intervals without any symptoms; thromboembolic or haemorrhagic episodes can, however, occur, mainly in uncontrolled ET. Development of terminal acute leukaemia has been reported in 34 cases. The expression of the influence of the treatments, 32P or alkylating agents, is very strong. The treatment of ET has to take in consideration the difficult compromise between balancing the necessity of preventing complications and the effects of drug toxicity. The use of recombinant alpha-interferon has recently been proposed and is under investigation. The pathogenesis of thrombocytosis in ET seems to involve an expansion in the megakaryocyte progenitor cell pool. Platelet membrane glycoprotein abnormalities and defective glycosylation of thrombospondin have been shown. Numerous other platelet abnormalities, including decreased alpha-adrenergic receptors, loss of PGD2 receptors and increased Fc receptors, have been reported. Arachidonic metabolism seems to be abnormal and lipoxygenase is defective. Most of the platelet abnormalities seem to be the result of intrinsic defects at the level of an abnormal clone of megakaryocytes. However, causal relationships between the platelet abnormalities and bleeding or thrombosis are not yet clearly demonstrated.
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PMID:Essential thrombocythaemia. 250 75

In an open prospective pilot trial, we tested the effect of recombinant interferon alpha-2 a (rIFN alpha-2 a) on thrombocytosis in myeloproliferative disorders (MPD). Since October 1986, 13 patients with MPD (4 with chronic granulocytic leukemia, 4 with polycythemia vera, 3 with essential thrombocythemia and 2 with myeloid metaplasia) were treated with rIFN alpha-2 a. Platelet counts decreased in all treated patients within 2 to 10 weeks from a median value of 1,050 x 10(9)/l (range 610-1,940 x 10(9)/l) to 340 x 10(9)/l (range 230-495 x 10(9)/l). The response was dose-dependent. In 11 patients we observed a simultaneous reduction of the white blood cell count. Six patients still continue the IFN alpha-2 a therapy. In 7 treatment was discontinued, because of chronic side effects in 3, and because of noncompliance in one. In these patients, thrombocytosis recurred after discontinuation of the therapy. These results show that rIFN alpha-2 a is effective in controlling thrombocytosis in MPD. However, the long-term benefit of interferon in these disorders remains to be established.
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PMID:Treatment of thrombocytosis in myeloproliferative disorders with interferon alpha-2a. 264 94

Megakaryocyte colony formation, as identified by conventional techniques, was observed in precursor cell cultures from peripheral blood in 8 of 20 consecutive patients with diagnosis of myeloproliferative disease (4/11 patients with polycythemia vera, 3/5 with essential thrombocythemia, 1/2 with primary osteomyelofibrosis and 2 with a myeloproliferative syndrome not further assessable), but not in 50 healthy controls (p less than 0.0001). 7 cultures showed spontaneous erythroid colonies, but were negative for megakaryocyte colonies. Megakaryocyte colony formation was independent of added erythropoietin, plasma or human leukocyte-conditioned medium, but was dependent on the presence of accessory cells. The cells in megakaryocyte colonies had the characteristic morphology of megakaryocytes and stained positively with the IIIa/IIb monoclonal anti-platelet antibody. Thus, megakaryocyte colony formation by precursor cells from peripheral blood in the absence of exogenous stimulating factors seems to be a phenomenon specific for myeloproliferative disease. Differential diagnosis of thrombocythemia may be facilitated by demonstration of endogenous megakaryocyte colony formation, which does not occur in secondary disease.
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PMID:Endogenous megakaryocyte colonies from peripheral blood in precursor cell cultures of patients with myeloproliferative disorders. 265 91

Our survey on the histology of the bone marrow in chronic myeloproliferative disorders (CMPD) basically gives a description of the relevant lesions of the different subtypes (i.e. chronic myeloid leukemia, primary osteomyelofibrosis, polycythemia vera rubra, and primary thrombocythemia) in correlation with important clinical findings, such as the myelofibrosis/sclerosis syndrome, blast crisis, and prognosis. In a schematic presentation, we assigned the main features of hematopoiesis, interstitial space, and bone tissue to the various subtypes of CMPD, taking into consideration, as well, the evolution of histomorphological lesions in the course of the disease process, which could be determined by means of sequential biopsies. Particularly in the early hyperplastic stages of primary osteomyelofibrosis and in primary (essential) thrombocythemia, we observed a considerable elevation of the platelet count, possibly leading to thrombosis and hemorrhage.
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PMID:[Histomorphologic findings of the bone marrow in chronic myeloproliferative diseases]. 268 47

The occurrence of polycythemia vera in a father, mother, and two sons is reported. Thirteen kindreds with familial polycythemia vera in 31 members are reviewed. Comprehensive records were available for all four patients as well as other family members, since all were diagnosed and treated at the author's institution over a period of nearly 50 years. The mean age at diagnosis, sex predominance, symptoms, and incidence of chromosomal abnormalities, leukocytosis, thrombocytosis, and elevated leukocyte alkaline phosphatase levels were similar to those of nonfamilial cases. The mean RBC volume at diagnosis and the incidence of splenomegaly appear to be higher in familial than nonfamilial cases. The mode of inheritance is unclear, but genetic factors may be involved in the pathogenesis of this myeloproliferative disorder.
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PMID:Familial polycythemia vera. 269 Nov 18

A 60-years-old woman with polycythemia vera with marked thrombocytosis and intolerable erythromelalgia was presented. A single dose of 400 mg aspirin was effective to improve the pain and cyanosis. And we studied the relationship between platelet aggregation rate and symptoms after administration of several antiplatelet drugs. A single dose of 100, 200, 400 and 800 mg aspirin, 25 mg indomethacin (Id), 200 mg OKY-046, and daily dose of 300 and 600 mg dipyridamole (Dp) and 300 mg ticlopidine (Tc) were given. Aspirin, Id and OKY-046 were effective for the improvement of finger pain. The complete inhibition of spontaneous aggregation (SPA) and aggregation by 2.0 micrograms/ml of collagen were well parallel with the improvement of symptoms. But duration of effect of LKY-046 were only 6 hours. Dp and Tc were not effective for the improvement of pain, had no relation with platelet aggregation rate. The concentration level of aspirin in vivo which suppresses the platelet aggregation induced by SPA and 2.0 micrograms/ml of collagen coincided well with the concentration level of this drug which suppresses the same platelet aggregation in vitro. It seems to be useful to suppress the platelet aggregation induced by SPA and 2.0 micrograms/ml of collagen with aspirin and Id for controlling the platelet aggregation induced circulatory disturbance in patient with thrombocytosis.
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PMID:[Clinical evaluation of the control of antiplatelet therapy through platelet aggregation rate on polycythemia vera associated with thrombocytosis and erythromelalgia]. 271 5

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

Essential thrombocythemia (ET) belongs to the group of clonal myeloproliferative disorders such as polycythemia vera (PV), chronic myelogenous leukemia (CML), and idiopathic myelofibrosis (MF). This rare disorder, characterized by an important thrombocytosis, includes a mucocutaneous hemorrhagic diathesis and thromboembolic events. Neurologic manifestations are frequent in ET and are due to obstruction of the cerebral microvasculature. Both thrombocytosis and platelet dysfunction can be responsible for the thrombo-hemorrhagic phenomena in ET. First symptoms of ET in our patient was thrombosis of the vertebral artery with a secondary embolic event in the thalamus region although the platelet count was below 600.10(9)/l, the classic diagnostic limit for ET. These data strongly suggest that qualitative platelet abnormalities rather than thrombocytosis are the main cause for thrombo-embolic events in ET.
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PMID:[Essential thrombocytosis]. 276 82

In 165 patients with chronic myeloproliferative disorders (CMPD) a morphometric and histochemical study was performed on trephine biopsies of the bone marrow to elucidate osseous remodeling by assessment of trabecular bone area (planimetry) and number of osteoclasts. Osteoclastic elements were identified by the tartrate-resistant acid phosphatase method. In addition to control specimens (n = 20) subtypes of CMPD included chronic myeloid leukemia (CML, n = 65), primary (essential) thrombocythemia (PTH, n = 25), polycythemia vera rubra (P. vera, n = 25) and agnogenic myeloid metaplasia (AMM, n = 50). AMM was discriminated into a so-called early hyperplastic stage without gross myelofibrosis (n = 19) and an overt or advanced stage showing fibro-osteosclerotic changes (n = 31). Total area of trabecular bone and counts for osteoclasts (uni- and multi-nucleated cells as well as a-nuclear cytoplasmic fragments) were not significantly increased in CML, PTH, P. vera and in the initial hypercellular stages of AMM. In contrast to these results, in advanced stages of AMM there was a significant increase in total bone area associated with a high count for all osteoclastic elements and apparently also an increased number of osteoblasts. It is speculated that the marked increase in osteoclastic-osteoblastic elements in late stages of AMM possibly reflects an imbalance of calcitriol (1.25-dihydroxyvitamin D 3) on skeletal homeostasis. This abnormal osseous remodeling may be mediated by the atypical megakaryocytic proliferation in this disorder, which is always a conspicuous feature of bone marrow biopsies.
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PMID:Osteoclasts and bone remodeling in chronic myeloproliferative disorders. A histochemical and morphometric study on trephine biopsies in 165 patients. 278 Apr 31


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