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)

In a prospective open study 16 consecutive patients with a myeloproliferative syndrome and thrombocytosis were treated with interferon (IFN) alpha-2a. 4 patients had polycythemia vera, 4 essential thrombocythemia, 3 myeloid metaplasia and 5 chronic granulocytic leukemia. Platelet counts decreased in all treated patients within 2 to 12 weeks from a median value of 1010 x 10(9)/l to 350 x 10(9)/l. No primary or secondary resistance was observed. The initial dose of IFN was 9 m U per day. After correction of the thrombocytosis, it was progressively reduced to a minimum dose of 3 m U per week. Despite the good platelet response to IFN, leukocytosis persisted in 3 patients and polycythemia in a further 3. Side effects and poor compliance required discontinuation of therapy in 6 patients. Special attention is focused on the follow-up in 6 patients who have been treated for more than 15 months.
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PMID:[Therapy of thrombocytosis in myeloproliferative syndromes using recombinant interferon-alpha-2a]. 279 42

Between March 1970 and February 1987, radiophosphorus (32P) was used to treat bone marrow disorders in 6 dogs; 4 had polycythemia vera and 2 had essential thrombocythemia. Activities of 32P given initially ranged from 2.4 to 3.3 mCi/m2. Four dogs responded well to 32P treatment, with gradual resolution of high RBC or platelet counts. Two of these dogs died of intercurrent disease unrelated to their bone marrow disorder, before blood counts could be stabilized. Two dogs did not respond to the initial 32P treatment nor to additional treatments with 32P, and had clinical signs and blood counts stabilized by use of phlebotomy or chemotherapeutic agents. We reviewed and analyzed 5 other cases of bone marrow disorders in dogs treated with 32P and included the findings from their records with the records of our 6 dogs in this retrospective analysis. Of the 8 dogs with polycythemia vera treated with 32P, 5 were given a single treatment that controlled clinical signs and blood counts for the remainder of the follow-up period. Of the 3 dogs treated for thrombocytosis with 32P, 2 had blood counts that responded to a single treatment.
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PMID:Radiophosphorus (32P) treatment of bone marrow disorders in dogs: 11 cases (1970-1987). 291 6

We performed a retrospective study on 21 patients, aged 70 years or more, affected by polycythemia vera (PV) or essential thrombocythemia (ET). As controls, we evaluated 10 younger ET patients. The results indicate that in older ET subjects there was a lower incidence of hemorrhagic and thrombotic complications than in younger patients and PV patients. However, platelet number and platelet function tests were similar in all the patients studied. We suppose that an increase in hematocrit as seen in PV is much more dangerous as compared to an isolated increase in platelet count, and that thrombocytosis alone in old age can be an isolated expression of a natural involution of blood marrow similar to myelofibrosis.
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PMID:The significance of thrombocytosis in old age. 311 7

Megakaryocytopoiesis in polycythemia vera (PV) was characterized by in vitro growth of marrow megakaryocytic progenitors (CFU-Meg) and quantitation of megakaryocyte numbers in marrow biopsy specimens in 14 patients with PV. Megakaryocyte numbers and CFU-Meg numbers in the 14 patients were variable, with values from the control range to markedly increased numbers. Nine of the 14 patients showed spontaneous CFU-Meg growth, and the presence or absence of spontaneous CFU-Meg growth was found to be related to the degree of marrow megakaryocyte increase, i.e., those with spontaneous CFU-Meg had higher megakaryocyte numbers. None of the plasmas from the PV patients contained detectable levels of megakaryocyte colony-stimulating activity (Meg-CSA), assayed using the culture with nonadherent normal marrow cells and tested plasma without phytohemagglutinin-stimulated leukocyte-conditioned medium as an exogenous source of Meg-CSA. Increased megakaryocyte numbers and resultant thrombocytosis in PV are likely based on the abnormal population of CFU-Meg.
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PMID:Megakaryocytopoiesis in polycythemia vera: characterization by megakaryocytic progenitors (CFU-Meg) in vitro and quantitation of marrow megakaryocytes. 312 55

Primary polycythaemia (PP), idiopathic myelofibrosis (MF), essential thrombocythaemia (ET) and chronic granulocytic or myeloid leukaemia (CGL) are clonal disorders of the pluripotent haemopoietic stem cells. We have studied granulocyte, megakaryocyte and erythroid progenitors from the peripheral blood of 7 patients with PP, 9 with ET, 19 with MF and 6 with CGL in order to characterise similarities and differences at the committed progenitor cell level. Spontaneous megakaryocytic and erythrocytic growth was characteristic of MF, PP and ET but was not seen in CGL. Circulating erythroid (BFU-E) and granulocyte/macrophage (CFU-GM) progenitors were markedly increased in MF and CGL, less raised in ET and closest to normal in PP. Erythropoietin-independent erythroid bursts (EIBFU-E) grew from the blood of patients with MF, PP and ET but spontaneous growth of megakaryocytes occurred in only MF and ET. These results suggest a progression of increasing abnormality from PP, where EIBFU-E occurred with relatively normal numbers of circulating progenitors, to ET where both EIBFU-E and megakaryocyte precursors regularly occur with elevated numbers of progenitors, to MF where spontaneous BFU-E, CFU-Mk and CFU-GM occur at high levels.
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PMID:Primary polycythaemia, essential thrombocythaemia and myelofibrosis--three facets of a single disease process? 312 58

60 patients with essential thrombocythemia (ET) have been retrospectively and prospectively followed from 1974 through 1987. The presenting signs and symptoms and the course of the disease were analyzed and compared to 10 patients with persisting reactive thrombocytosis selected from 6,000 patients with reactive thrombocytosis and to 50 patients with other myeloproliferative diseases. 54 ET-patients presented with complications, 46 with thrombembolic, 3 with hemorrhagic problems and 5 with thrombembolic and hemorrhagic problems. In 6 patients ET was detected accidentally. Disturbances of the microcirculation, mainly of the fingers and the toes, were the most frequent symptom. The average maximal platelet count was 1,207,000/microliter. The average platelet count at diagnosis was 880,000/microliter. 16 patients had an elevation of the serum creatinine at diagnosis, which deteriorated during the course of the disease. Bone marrow examinations were performed in 56 patients, histology in 48 patients, cytology in 29 patients. In contrast to the clinical diagnosis the histological diagnosis was in 4 cases each polycythemia vera and myeloproliferative syndrome without further specification. 12 patients died thus far. The causes of death were thrombembolic complications in 9, acute leukemia in 2 patients, in 1 patient the cause of death is not known. 10 years after diagnosis 61% of the patients are still alive. It appears that ET is a more important risk factor for the disturbances of the micro- and macrocirculation than has been recognized until now. ET is, if thrombembolic complications are avoided, a disease with a relatively benign course.
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PMID:[Clinical characterization of essential thrombocythemia in comparison with other myeloproliferative diseases and reactive thrombocytoses]. 316 63

A morphometric analysis of bone marrow biopsies was performed in 25 patients each with clinical diagnoses of primary (essential) thrombocythemia (PTH) and polycythemia vera rubra (P. vera) according to the rigid diagnostic criteria of the Polycythemia Vera Study Group to reveal significant differences in the histomorphologic features between these disorders. In comparison with control specimens of patients without any hematologic disease, megakaryocyte proliferation was most prominent in PTH, even exceeding that of P. vera with concomitant thrombocythemia (11 of 25 cases with a platelet count greater than 600 X 10(9)/L). Moreover, in P. vera there were wide ranges of megakaryocyte sizes, consisting of micro-megakaryocytes as well as giant forms with highly segmented nuclei (four nuclear lobes), which gave the cells a pleomorphic appearance. As compared with the normal bone marrow, the amount of neutrophilic granulopoiesis and erythropoiesis was not significantly increased in PTH, in contrast to P. vera. Similar results were obtainable regarding the density of reticulin (argyrophilic) fibers: a normal content was encountered in the control specimens and PTH, whereas P. vera displayed a minimal-to-slight increase. Finally, the bone marrow of P. vera was totally devoid of stainable iron while hemosiderin deposits were detected in about two-thirds of the patients without hematologic disorders and in PTH. The characteristic differences revealed by this morphometric study may lead to an improvement of the controversial histologic diagnosis in these disorders.
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PMID:Primary (essential) thrombocythemia versus polycythemia vera rubra. A histomorphometric analysis of bone marrow features in trephine biopsies. 320 62

Anagrelide is a member of the imidazo (2,1-b) quinazolin-2-one series of compounds, with a powerful antiaggregating effect on platelets. During studies in humans, anagrelide in small doses has produced thrombocytopenia. We therefore evaluated it in the treatment of thrombocytosis, and to date, platelet levels in 15 of 17 patients with primary thrombocythemia, 2 patients with polycythemia vera and thrombocytosis, and 1 patient with chronic granulocytic leukemia and thrombocytosis have been well controlled with the use of this agent. Induction doses of 1.0 to 1.5 mg given orally every six hours have produced a decrease in the platelet count, starting on day 5 and reaching a normal level by day 12. Side effects of anagrelide have been minimal. Maintenance therapy with 1.5 to 4.0 mg a day has continued to control the platelet count in patients for up to 28 months. This new agent appears promising in the treatment of thrombocytosis in patients with chronic myeloproliferative disease.
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PMID:Anagrelide: a new drug for treating thrombocytosis. 336 87

Transformation to acute leukemia (AL) is known to occur in polycythemia vera (PV) and essential thrombocythemia (ET). Myelosuppressive therapy with agents such as 32P and alkylating agents increase this risk in both disorders. The alkylating agent, uracil mustard (UM), which is an effective agent for controlling thrombocytosis, has not been reported to be leukemogenic. We have treated 29 patients with UM (9 treated continuously and 20 treated intermittently): II with PV, 16 with ET, and 2 with myelofibrosis (MF). Three patients developed AL, two after continuous therapy. These two patients with PV had received the fourth highest and highest total dose of UM, and their duration of treatment was the third and fourth longest among the nine patients treated continuously, respectively. One out of 20 patients treated intermittently with UM developed AL. This patient (3) with ET had received the highest total dose of UM, and her duration of treatment was the longest among the 20 patients treated intermittently.
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PMID:Acute leukemia following treatment of polycythemia vera and essential thrombocythemia with uracil mustard. 230 74

Alkylating agents and 32P have been widely employed in the treatment of patients with essential thrombocythemia (ET). During a four-month period, we observed 3 cases of ET that had transformed into leukemia. Two patients had been treated with uracil mustard: One developed acute myelogenous leukemia 79 months after institution of therapy, and the other patient developed chronic myelomonocytic leukemia 24 months after the start of therapy. The third patient had been treated with busulfan, and ET evolved into myelofibrosis and eventually into acute undifferentiated leukemia with myelofibrosis. The patient who developed acute myelogenous leukemia was asymptomatic at the time of diagnosis of ET but was treated because his platelet count was greater than 1,000,000/mm3. He died 1 month after leukemic transformation, during induction chemotherapy. The other 2 patients presented with symptoms referable to their thrombocythemia. Review of the English literature revealed 12 other definite or probable cases of ET with leukemic transformation, all but 1 having been treated with alkylating agents and/or 32P. We propose that the natural history of ET may be similar to that of polycythemia vera, with evolution into leukemia being an unusual occurrence except in the setting of previous chemotherapy. Therefore, the current practice of treating asymptomatic patients with ET may not be justified, since administration of alkylating agents or 32P may increase the risk of subsequent development of leukemia.
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PMID:Essential thrombocythemia and leukemic transformation. 346 86


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