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

Peripheral blood mononuclear cells from a patient with polycythemia vera were cultured in a methylcellulose system employing human serum. Electron microscopy documented the appearance of mixed colonies containing lymphocytes, granulocytes, megakaryocytes, and erythrocytes. In vitro culture characteristics were similar to those seen for other patients with polycythemia ver, ie, colonies grew in the absence of added erythropoietin or other pathway-specific regulators. Plating efficiency was linearly related to the number of cells plated, which supports the concept that each colony arose from a single cell. The appearance of mixed myeloid-lymphoid colonies points to the existence of a primitive stem cell capable of giving rise to multiple hematopoietic cell lines.
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PMID:Mixed myeloid-Lymphoid colonies in a patient with polycythemia vera. 711 54

Recent data concerning in vitro studies of erythroid progenitors in polycythemia vera (PV) are reviewed. As shown by different laboratories, at least two populations of CFUE seem to coexist in the bone marrow of such patients: one exhibits normal in vitro behavior; the other, probably of clonal origin, is abnormally sensitive to erythropoietin. This abnormal population of CFUE is highly sensitive to trace amounts of erythropoietin and is probably responsible for the in vivo development of polycythemia despite a depressed level of erythropoietin. At the BFUE level, two populations also seem to coexist. However, the abnormal behavior of erythroid progenitors is probably not expressed at this early level of differentiation but only at the late CFUE level. This is in agreement with some of the data, which suggest that in the differentiation of erythroid progenitors into erythroblasts, erythropoietin is only needed at a level very close to CFUE.
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PMID:Erythroid progenitors in polycythemia vera. 718 45

Biopsies of the posterior iliac crest, greater trochanter, and proximal tibia were done for 27 polycythemic patients before myelosuppressive therapy was begun. Five had relative polycythemia, thirteen had secondary polycythemia, and nine had polycythemia vera. None of five biopsy specimens of the greater trochanter in cases of relative polycythemia contained myeloid tissue (erythroblasts, granulocytic precursors, and megakaryocytes). Four of six biopsy specimens of the greater trochanter and one of eight of the tibia in cases of secondary polycythemia contained myeloid tissue. All seven biopsy specimens of the greater trochanter and two of five biopsy specimens of the proximal tibia in cases of polycythemia vera contained myeloid tissue. A trochanter biopsy specimen devoid of myeloid tissue probably eliminates the diagnosis of polycythemia vera. Myeloid tissue extends from the axial skeleton to the greater trochanter, therafter to the tibia. Extension of myeloid tissue does not imply that marrow failure is imminent in polycythemia vera.
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PMID:Extension of myeloid tissue into the lower extremities in polycythemia. 742 24

We measured serum concentrations of erythropoietin in 59 patients with polycythemia using a sensitive and specific radioimmunoassay. The mean concentration was 17.5 +/- 8.4 mU/mL (+/- SD) in 26 patients with polycythemia vera and 14.9 +/- 4.2 mU/mL in 26 normal persons. In contrast, the average concentration was 94.3 +/- 101.2 mU/mL in 33 patients with secondary polycythemia, representing a highly significant elevation (p < 0.0001) compared to both normal and polycythemia vera groups. The average hematocrit value did not differ between the polycythemia vera and the secondary polycythemia patients, and both groups had higher values (median, 55%) than the normal donors (median, 41%). Erythropoietin concentrations ascertained by radioimmunoassay helped discriminate between polycythemia vera and secondary polycythemia. Ninety-two percent of polycythemia vera patients had concentrations less than 30 mU/mL (the concentration used as a cut off point), and 94% of secondary polycythemia patients had concentrations greater than 30 mU/mL. This represents an overall correct classification of 93% of the patients. Serum erythropoietin levels as ascertained by radioimmunoassay can distinguish between most polycythemia vera and secondary polycythemia patients and should prove useful in the differential diagnosis of polycythemia.
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PMID:Erythropoietin radioimmunoassay in evaluating patients with polycythemia. 744 23

In an autopsied female primary polycythemia was definitely diagnosed only after histological examination. A classical form of Vaquez-Osler disease was characterized by pronounced normo-, granulo- and megakaryocyte hyperplasia of the bone marrow, spleen and liver myelosis with an admixture of atypical megakaryocytes and splenomegaly. There was a complication in the form of two coronary arteries thrombosis. Lethal outcome resulted from myocardial infarction.
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PMID:[Polycythemia vera, complicated by myocardial infarction]. 767 90

The common origin of myeloproliferative disorders can explain the possible evolution of polycythemia vera to post-polycythemia myeloid metaplasia (PPMM). Such a possible event is usually considered linked to the use of myelosuppressive agents in particular 32P. Occasionally, myelofibrosis following essential thrombocythemia has also been described. We report here 19 cases of post-polycythemia myeloid metaplasia out of 214 polycythemia vera patients (8.8%). The majority of these patients received 32P therapy. However, busulfan also seems to have some role in the modification of polycythemia vera. In particular, the association of more than one myelosuppressive agent may favour the evolution of PPMM.
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PMID:Post-polycythemia myeloid metaplasia: experience with a large cohort of patients. 776 74

A few simple, low-priced, outpatient investigations, including an upper abdominal ultrasonography, a measurement of the arterial oxygen saturation and, in some cases, a leukocyte alkaline phosphatase score (LAP) suffice to find out the etiology of an increased red cell mass in most patients. The diagnosis of polycythemia vera (PV) could be accepted in patients with an increased red cell mass if the spleen is enlarged and if the arterial oxygen saturation is normal, although the latter measurement may not be required in typical cases. If the spleen is not enlarged, the diagnosis of PV could be accepted if, in addition, the leukocyte or thrombocyte count is increased. An elevated LAP score also points to the diagnosis of PV, provided fever or inflammation are not present. If, at that stage, an etiologic diagnosis has not been made, smoker's polycythemia should be considered and excluded. The next step should include a serum erythropoietin assay and culture of erythroid stem cells before performing investigations aimed at ruling out the many conditions associated with secondary polycythemia.
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PMID:Biological and radiological investigations in patients with an increased red blood cell mass: Which are needed? Which are useful? which are unnecessary? 803 33

In vivo and in vitro bioassays, radio immunoassays (RIA), enzyme linked immunoassays (ELISA) and immunoradiometric assays (IRMA) have been applied to measure serum erythropoietin (Epo) levels. Results are expressed in international units (IU). In vivo bioassays are time consuming, expensive and not sensitive enough to measure the amount of Epo in normal sera. Nevertheless, this test remains the standard of comparison for the other new assays. Immunologic technics are specific, sensitive, reproducible, easy to perform, rapid and are now preferred for the measurement of Epo. Published values for non anemic human range from 6 to 32 IU/l. In the search of etiology of a polycythemia, the results of usual investigations to class the polycythemia either as primitive (P. vera) or secondary are often inconclusive. In these situations, measurement of serum Epo could be of value for accurate a differential diagnosis. However the results of the literature and our personal experience, show that the serum Epo level does not discriminate with an absolute fiability between Polycythemia Vera and secondary polycythemia because of a great overlap between the two groups.
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PMID:Determination of serum erythropoietin. Its value in the differential diagnosis of polycythemias. 803 36

We present a patient diagnosed of polycythemia vera who developed a multiple myeloma 13 years after the initial diagnosis of polycythemia vera. Although an unusual finding, another 17 patients with polycythemia and myeloma have been described. In some patients the diagnosis of both diseases was simultaneous but in most cases myeloma developed years after polycythemia vera. Some patients received only venipuncture for treatment of polycythemia vera so the appearance of multiple myeloma could not be explained on the grounds of chemotherapy induced second neoplasm. An explanation for this association is suggested.
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PMID:[Association of polycythemia vera and multiple myeloma. Presentation ofa new case and review of the literature]. 817 87

A 42-year-old Caucasian male with sporadic primary polycythemia has been followed by us for 13 years. During the time of observation, his hemoglobin had been stable, and he has never had an elevated white count or platelet count or any other stigmata of polycythemia vera (PV). Both of his parents, his three children, and all siblings have been hematologically normal. The in vitro culture of erythroid progenitors revealed an absence of autonomous erythropoietin (Epo)-independent erythroid colonies but demonstrated a marked increase in the sensitivity of erythroid progenitors to Epo. We have undertaken a study designed to determine whether a mutation in the Epo receptor (Epo-R) gene could cause the polycythemia phenotype seen in either dominant or recessive primary polycythemia described by us and others, or in polycythemia vera. We have sequenced the cytoplasmic positive and negative regulatory domains of the Epo-R genomic DNA, and a transversion of C to T in nucleotide 6148 was found in one of the patient's chromosomes. This mutation is located in the negative regulatory domain and results in a change from proline to serine (P488S). We have subsequently analyzed more than 40 chromosomes from unrelated normal subjects, as well as autosomal dominant, recessive, and sporadic primary polycythemia and polycythemia vera subjects. In no instance was the same or any other mutation in the Epo-R found. To determine if this Epo-R mutation is a cause of increased sensitivity of erythroid progenitors to erythropoietin, Ba/F3 cells (interleukin-3-dependent murine lymphoid line) were transfected with normal and mutated Epo-R cDNA, rendering the transfected cells viable and able to proliferate in Epo. Transfectants with wild-type and mutant Epo-R cDNA exhibited no difference in the presence of Epo. More recently, we were able to obtain DNA from the seven family members of the propositus and found that the nonpolycythemic mother and one of the siblings have the same Epo-R mutation. We conclude that this first described mutation of Epo-R encountered in humans does not appear on its own to explain the polycythemia phenotype; however, the possibility that it may interact with some other acquired or congenital abnormality in generating the polycythemia phenotype cannot be excluded.
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PMID:Mutation in the negative regulatory element of the erythropoietin receptor gene in a case of sporadic primary polycythemia. 817 75


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