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

The author provides data pertinent to the modern classification of erythrocytosis, which rests on the pathogenetic principle. The difference in the pathogenesis of erythremia and secondary erythrocytoses was proved with the help of an erythroid culture and by examination of erythropoietins, which can be thus used for diagnostic purposes. Analysis of so-called "pure" erythrocytosis has shown that this term implies different patterns of erythrocytosis from the standpoint of the pathogenesis: erythremia, secondary erythrocytoses that are difficult to diagnose, and hereditary erythrocytosis associated with erythropoietin hyperproduction. There is no evidence for the existence of the "pure" erythroid leukemia and thus the author doubts this disease entity. Analysing the different patterns of secondary absolute erythrocytosis the author discusses specific problems of their pathogenesis. Attention is paid to erythrocytosis of a tobacco smoker, to the role of obesity and concomitant action of some factors on the development of hypoxic erythrocytosis. The data are presented on the new types of erythrocytosis, on the post-transplantation one, in particular, which occurs after kidney transplantation, and finally on erythrocytosis that develops occasionally in patients on hemodialysis. Attention is paid as well to relative erythrocytoses, risk factor in the development of thrombotic complications. The problems of etiologically and pathogenetically valid therapy of secondary erythrocytoses are reviewed.
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PMID:[Secondary erythrocytoses]. 404 68

Severe erythrocytosis is associated with increased whole blood viscosity and impaired blood flow. Since a reduced blood flow will cause tissue hypoxia and since tissue hypoxia is associated with increased synthesis of erythropoietin, erythrocytosis per se should cause an increase in the rate of red cell production. This, however, does not occur and severe erythrocytosis in patients with polycythemia vera does not lead to increased synthesis of erythropoietin. We propose here that the reason for this discrepancy is that decreased blood flow to the kidneys, the site of erythropoietin synthesis, does not cause renal tissue hypoxia. The oxygen tension in the kidneys is to a great extent determined by the consumption of oxygen used for sodium reabsorption and since sodium reabsorption is roughly proportional to glomerular filtration, a decreased flow of blood should be matched by a decreased oxygen consumption leaving the tissue tension of oxygen unchanged. Consequently, the location of an oxygen sensor in the kidneys controlling erythropoietin production appears to be most fortuitous since it prevents the development of a vicious circle, with erythrocytosis causing more erythrocytosis.
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PMID:Why the kidney? 405 20

The quantitative relationship between red cell volume, erythropoietin level, and erythropoiesis was evaluated in 43 human beings. Results in normal man were compared with studies in patients with anemia from bone marrow failure and with polycythemia vera. The maximum erythropoietin excretion after bleeding normal men was similar to the basal levels found in patients with chronic anemia of similar magnitude. Although erythropoietin values were low in patients with polycythemia vera, bleeding evoked a normal response. In patients anemic from bone marrow failure, basal levels were elevated, and phlebotomy resulted in an increase consistent with the new level of anemia. These observations indicate that erythropoietin level is affected primarily by the degree of anemia and is not influenced by the duration of anemia. In normal subjects, a fivefold increase in urinary erythropoietin was associated with a doubling of erythropoiesis. Despite similar degrees of erythropoietin production, anemic patients with evidence of bone marrow in the lower extremities had greater red cell production. In patients with polycythemia vera, red cell production was inappropriately elevated with regard to the urinary erythropoietin excretion. Bone marrow maturation time was not shortened in patients anemic from bone marrow failure to the same degree as in bled, normal volunteers. In addition to an adequate level of erythropoietin production, normal bone marrow function is necessary for maximal shortening of maturation time.
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PMID:Erythropoiesis in the anemia of bone marrow failure. 547 82

The myeloproliferative disorders, including polycythaemia rubra vera, arise as a result of a single-cell mutation. A characteristic of the abnormal haemopoietic clone is that it can form erythroid colonies in vitro in the absence of added erythropoietin. Such endogenous erythroid clones were consistently found in two of seven patients with peripheral vascular disease. These two patients had mean platelet counts of 600 X 10(9)/l and 630 X 10(9)/l. Culture of blood and bone-marrow cells from patients with raised platelet counts secondary to a variety of other disorders failed to yield such colonies. The presence of endogenous erythroid clones provides early evidence of a myeloproliferative disorder.
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PMID:Formes frustes in myeloproliferative disorders. Identification by the growth of an endogenous erythroid clone in vitro in patients with arterial vascular disease. 611 13

In eight patients with polycythaemia vera and 20 normals, mononuclear cells of the peripheral blood were cultured in methylcellulose with and without exogenously added erythropoietin. The cultures were set up with fetal calf serum and with a serum-free medium of unsaturated fatty acids, lecithin and cholesterol. In patients with polycythemia vera, we found a proliferation of haematopoietic colonies without erythropoietin in both culture systems which could not be seen in normals. The proliferation of endogenous colonies in serum-free media suggests that polycythaemia vera is a clonal disorder which can be modulated by serum factors and by erythropoietin.
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PMID:Proliferation of haematopoietic colonies in serum-free cultures. 619 51

Four adolescents with polycythaemia are described where symptoms typical of the disease had already existed in childhood. Three patients fulfilled the criteria of a polycythaemia vera. In one female patient the possibility of familial erythrocytosis is discussed. Polycythaemia vera mononuclear cells formed erythroid colonies in cultures in the absence of erythropoietin. The patients were phlebotomized to maintain haematocrit readings of 40 to 45%. No case has yet progressed to myeloid metaplasia or acute leukaemia.
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PMID:Primary polycythaemia in childhood and adolescence. 620 Apr 7

Mononuclear cells from peripheral blood of six patients with polycythemia after kidney transplantation were studied in methyl cellulose cultures using fetal calf serum with and without adding erythropoietin. Parallel tests were run with "synthetic medium". The data obtained were compared to those of patients with polycythemia vera and normal subjects. The erythropoietin independent proliferation in synthetic medium typical for polycythemia vera could not be found in patients with renal grafts. However, in the preparations with fetal calf serum without erythropoietin, a formation of erythroid colonies could be detected suggesting an increased sensitivity or proliferation of erythropoietically determined stem cells in patients with transplanted kidneys.
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PMID:Studies in polycythemia after kidney transplantation. 635 9

A commercially available hemagglutination inhibition assay kit for the measurement of erythropoietin (EPO) was evaluated for its usefulness in the differential diagnosis of the polycythemic states. Serum samples were obtained from patients with polycythemia rubra vera (active and controlled), secondary and relative polycythemia and from normal controls. Firstly, we found that the mean EPO level (+/- SD) of our normal controls (81 +/- 69 miu/ml) was higher than the manufacturer's quoted normal range (15-59 miu/ml) and that there was a significant spread of values (7-233 miu/ml). Secondly, within each patient subgroup studied, the spread of data points was so wide that interpretation of individual data points would be impossible. We conclude that this assay kit is of little value for serum EPO estimation and in the differential diagnosis of polycythemia.
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PMID:An evaluation of serum erythropoietin estimation by a hemagglutination inhibition assay in the differential diagnosis of polycythemia. 646 79

We have studied the behavior in culture of circulating restricted hemopoietic progenitor cells from patients with idiopathic myelofibrosis (IMF), polycythemia vera (PV), and essential thrombocytopenia (ET). We have found differences in circulating granulocyte-macrophage, erythroid, and megakaryocytic progenitors that appear to be specific for these chronic myeloproliferative disorders. In IMF, most affected were granulocyte-macrophage progenitor cells (CFU-C), which circulated in increased numbers and were heterogeneous in their sensitivity to the regulatory factor(s) present in phytohemagglutinin (PHA) stimulated T-lymphocyte conditioned medium (CM). Most CFU-C were either highly sensitive to, or independent from, stimulatory factors, while others showed normal sensitivity. In some IMF patients, circulating megakaryocytic progenitors (CFU-M) were present that were capable of giving rise to colonies in the absence of added CM or erythropoietin (EPO). In PV, we confirmed the presence of circulating erythroid progenitor cells that give rise to colonies in culture without the addition of EPO. The number of circulating CFU-C was normal and they responded normally to CM. In ET, failure to detect 7-day circulating restricted progenitor cells was a common observation; the level of other circulating restricted progenitors was in the low normal range. Thus, despite certain common features, including a primary lesion at the level of the pluripotential hemopoietic stem cell, the myeloproliferative disorders differ with respect to the behavior in culture of their circulating restricted progenitor cells. These results have led us to postulate a second regulatory lesion in the pluripotential stem cell that differs in these disorders and is expressed at the level of the respective restricted progenitor cells.
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PMID:Differences among myeloproliferative disorders in the behavior of their restricted progenitor cells in culture. 660 77

Symptomatic erythrocytosis developed in a 59-year-old man with polycystic kidney disease (PKD) while he was receiving maintenance hemodialysis. Major clinical and laboratory data suggested a diagnosis of polycythemia vera (PV), despite a normal serum alkaline phosphatase level and leukocyte count. Secondary erythrocytosis, related to chronic hypoxemia and increased erythropoietin production, was excluded by appropriate laboratory studies. Despite previous documentation of secondary erythrocytosis in patients receiving hemodialysis, to my knowledge, PV has not been described in this population.
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PMID:Polycystic kidney disease and polycythemia vera. Occurrence in a patient receiving hemodialysis. 661 11


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