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Results for “Polycythemia Vera”

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At least 19 recordsLinked to original sources

PubMed1978

Chromosome studies in polycythemia vera.

Polycythemia vera (PV) represents an apparent monoclonal stem cell proliferation with a frequent transition to full neoplastic behavior. Up to 26% of untreated PV patients can be expected to have some chromosome abnormalities in the marrow at the time of diagnosis, and 10--15% have an abnormal cell line or clone. Both structural and numerical aberrations occur. Aneuploidy is the most common type of chromosome abnormality, however, with hyperdiploid clones occurring more frequently than hypodiploid clones. Chromosomes 1, 8, 9 and 20 are involved in a non-random pattern, and aberrations of all the F group, or at least the No. 20 chromosome seem to be associated to some extent with diseases involving erythroid hyperplasia. Leukemia develops in a certain percentage of patients regardless of the type of treatment they have received, but the relationship, if any, between the chromosome abnormalities and the development of leukemia is still uncertain. The abnormal clones that occur in PV appear to be quite stable and there is no indication at this time that they correlate with a prognosis of leukemic transformation.

Aneuploidy↗

PubMedDate not supplied

Hyperlipidemia and myocardial infarction among 118 patients with polycythemia vera.

Hyperlipidemia was reported among 46 of 118 polycythemia vera patients as compared to a control group of 115 healthy subjects in whom hyperlipidemia was reported in 20. Among the 46 hyperlipidemic patients with polycythemia vera 14 had a myocardial infarction, while among the other 72 nonhyperlipidemic polycythemia vera patients myocardial infarction occurred amont 17. Since repeated phlebotomies may induce hyperlipidemia, this form of treatment of polycythemia vera may be potentially dangerous in already hyperlipidemic polycythemia vera patients.

Female↗

PubMed1975

Pentose shunt, phosphoribosylpyrophosphate generation and purine-phosphoribosyltransferases in erythrocytes of patients with polycythemia vera.

Erythrocytes of patients with polycythemia vera exhibited increased activity of oxidative pentose shunt, accelerated generation of phosphoribosylpyrophosphate, increased incorporation of 14C-adenine into nucleotides, and increased activity and thermostability of adenine-phosphoribosyltransferase. These abnormalities are attributed to age dependency of the pathways concerned and presence in polycythemia vera of an erythrocyte population younger than normal.

Adenine↗

PubMed1977

Prolonged remission of leukemia associated with polycythemia vera.

A patient with polycythemia vera (PV) received successive treatment by phlebotomies, radioactive phosphorus, myleran and cyclophosphamide. Sixteen years after the diagnosis, he developed acute myeloblastic leukemia. A complete remission was achieved following two courses of COAP (cyclophosphamide, vincristine, Cytosine Arabinoside, and prednisone) therapy. Four months later, while still in leukemic remission, he became mildly polycythemic again and the treatment with phlebotomies and cyclophosphamide was resume. The patient has subsequently been in complete remission of leukemia for over three years and his polycythemia is controlled by small doses of cyclophosphamide. This appears to be a unique case of such a prolonged remission of leukemia in the course of PV, with a return to a mild polycythemia state.

Aged↗

PubMed1978

Hyperlipemia and myocardial infarction in polycythemia vera.

Hyperlipemia was found in 46 of 118 polycythemia vera patients and in 20 of a control group of 115 healthy subjects. Myocardial infarction in the polycythemia vera group occurred in 14 of the 46 hyperlipemic and in 17 of the remaining 72 nonhyperlipemic patients. Repeated phlebotomies may induce hyperlipemia; therefore, this form of treatment may be potentially dangerous in polycythemia vera patients who are already hyperlipemic.

Female↗

PubMed1979

Endogenous erythroid colony formation by peripheral blood mononuclear cells from patients with myelofibrosis and polycythemia vera.

Peripheral blood mononuclear cells from patients with polycythemia vera or myelofibrosis with myeloid metaplasia were studied for their erythroid colony growth characteristics in plasma clot cultures. In both diseases, erythroid colonies formed early in culture in the absence of added erythropoietin (endogenous colonies). In no instance did early, endogenous colony formation occur with peripheral blood cells from normals or patients with secondary polycythemia. A normal response to erythropoietin was observed with both control and patients' peripheral blood cells. Spleen mononuclear cells obtained from one patient with myelofibrosis also produced endogenous colonies and showed a response to erythropoietin. This study suggests that culture of peripheral blood mononuclear cells might serve as a useful tool in discriminating polycythemia vera from secondary polycythemia.

Cells, Cultured↗

PubMed1978

Cell separation, cell differential and granulocyte colony frequency in polycythemia vera.

In seven patients with polycythemia vera, the agar colony growth of bone marrow total nucleated cell suspensions and of the cell fractions obtained with an albumin discontinuous density gradient were studied. In one patient, the density distribution of colony-forming units in culture (CFUc) before and after alkylating treatment was evaluated and cell differentials on smears obtained from each density fraction were determined. A high percentage of low density CFUc compared with the total CFUc population and with that in the normal control subjects in the same density fractions was observed.

Bone Marrow↗

PubMed1977

Inappropriate erythropoietin secretion in polycythemia vera.

A patient with classical polycythemia vera (PV) was found to have an inappropriately elevated serum erythropoietin (Ep) level. Investigations did not reveal any lesion or blood abnormality known to be associated with excessive Ep production and erythrocytosis. Sudden withdrawal of blood to reduce the Hb and Hct from 18.5 gm% and 56% to 13.6 gm% and 41.5%, respectively, resulted in an increment of serum Ep to abnormal level. With iron treatment there was a brisk return of Hb and Hct to prebleeding levels which was associated with reduction in the serum Ep. The inverse relationship between the Ep and Hb or Hct is inconsistent with the presence of excessive Ep-producing lesion. These results suggested that the threshold for Ep secretion from normal Ep-secreting tissue to Hb and Hct levels is set at an abnormal level. This patient's marrow cells when cultured in vitro in the absence of Ep, unlike other PV patients' (except one) marrow cells, did not grow erythroid colonies. In the presence of Ep, however, the colonies comparable to those formed from normal marrow cultures were obtained. These results suggested that his marrow erythropoietic cells were neither Ep independent nor Ep-hyperresponsive, as has been suggested by some investigators for erythropoiesis in PV. This patient presents phenomena that hitherto have not been reported.

Animals↗

PubMed1976

Pathogenesis of polycythemia vera--new concepts.

Data presently available suggest that polycythemia vera is an acquired clonal disorder of the pluripotent stem cell resulting in expansion of committed stem cell pools, most prominently in the erythroid line. In vitro and in vivo studies suggest that erythropoiesis in polycythemia vera is at least partially modulated by erythropoietin.

Erythropoiesis↗

PubMed1977

Neutrophil marrow egress in polycythemia vera.

Neutrophil marrow egress was examined in 6 polycythemia vera patients using 3H-thymidine (3H-TDR) pulse labeling. The granulocytopoietic proliferation activity ranged between moderate depression (1420 neutrophils per mul blood) and marked enhancement (22470 neutrophils per mul blood). Egress characteristics did not significantly deviate from the ones found in subjects with normal granulocytopoietic proliferation activity. Shortest cell sojourn in the medullar nonproliferating granulocytopoietic pool before cell transit into the blood, i.e. "neutrophil emergence time", ranged between 67-102 h (median 76 h). After this time interval labeled band and segmented neutrophils simultaneously appeared in the peripheral blood. However, during the early influx phase of labeled neutrophils labeling indices of band forms increased more rapidly than that of segmented forms. In segmented forms the initial curve increment followed approximately an exponential function. Labeling indices doubled in 10-13.5 h with remarkably small variance in the different disease states examined. The results indicate that the main factors influencing neutrophil marrow egress, i.e. maturation of granulocytopoietic cells, structure of marrow sinusoids and control mechanisms, function normally in polycythemia vera.

Aged↗

PubMed1978

Polycythemia vera. The in vitro response of normal and abnormal stem cell lines to erythropoietin.

Bone marrow cells from two glucose-6-phosphate dehydrogenase (G-6-PD) heterozygotes with polycythemia vera were cultured to determine whether progenitors which wre not of the polycythemia vera clone were present, and, if present, which cell lines contributed to the increase in erythroid colonies observed in response to added erythropoietin (ESF). To accomplish this, the G-6-PD isoenzyme activity of individual erythroid colonies was determined. All of the erythroid colonies analyzed in cultures without added ESF, contained the G-6-PD isoenzyme type characteristic of the abnormal clone. With higher ESF concentrations in the culture, however, there was an increase in the colonies that were not of the polycythemia vera clone. Analysis of the ratio of the various types of colonies indicated that normal and polycythemia vera cells are capable of responding to ESF in vitro. In selected patients, this technique permits analysis of the ratios of normal to abnormal cells during the course of the disease, in response to therapy and during late complications, such as myelofibrosis or leukemic transformation.

Clone Cells↗

PubMed1979

Two cases of choreatic syndrome caused by polycythemia vera.

Two patients with choreatic syndromes caused by polycythemia vera recovered after treatment of the polycythemia by only two venesections: this proves that the syndrome is due to reversible alterations. Investigations of the cerebral circulation in one of the patients showed that blood flow was lowest in the grey matter at the basal region of the brain: this suggests that the alterations might mainly occur there. However, investigation of erythrocyte rheology, glucose-6-phosphate dehydrogenase, serum concentrations of caeruloplasmin and serotonin, and urinary excretion of epinephrine, norepinephrine and vanillylmandelic acid gave normal results in both patients. There are therefore no indications as to the possible pathophysiology of these alterations. There are now 24 cases reported, including our 2 patients, which suggests that the association of these two diseases may not be so rare as supposed.

Adult↗

PubMed1975

Decreased (Ca2+ + Mg2+)-stimulated ATPase activity in erythrocyte membranes from polycythemia vera patients.

Erythrocytes were hemolyzed in hypotonic phospate buffer containing 0.5 mmol/l Ca2+ and the membranes subsequently washed twice in hypotonic tris buffer. The centrifugation was performed in a continuous flow system, which was necessary to obtain maximal ATPase activity. The Mg2+-dependent Ca2+-stimulated ATPase activity of 14 patients with polycythemia vera was only 67 per cent (P less than 0.001) of the activity of a control material consisting of 10 donors and 11 bank blood specimens. Five patients with secondary polycythemia and four patients with an increased erythrocyte fraction did not differ significantly from the controls. The polycythemia vera patients with the highest leukocyte count showed the lowest ATPase activity. The apparent calcium dissociation constant of the ATPase in polycythemia vera was about 10(-6) mol/l, as in controls. The relation between the reduced ATPase activity and the abnormal hemopoiesis of polycythemia vera patients is discussed.

Adenosine Triphosphatases↗

PubMed1978

Dental management of mild hemophilia with polycythemia vera.

Classic hemophilia (hemophilia A. Factor VIII deficiency, antihemophilic factor deficiency) and polycythemia vera were diagnosed in a patient who presented for management of his dental disease. This case report summarizes the history, laboratory findings, and clinical course and discusses the various diagnostic considerations in the management of two rare disorders. A review of current concepts of hemophilia and polycythemia vera is presented.

Adult↗

PubMed1977

Polycythemia vera: hormonal modulation of erythropoiesis in vitro.

We performed in vitro culture studies examining the interaction of erythropoietin with red cell progenitors in polycythemia vera. Bone marrow was obtained from five patients with typical disease and from five healthy volunteers, and assayed for erythroid colony formation (CFU-E) by the methylcellulose technique. In cultures without added erythropoietin, a mean eightfold greater cloning efficiency was noted with the polycythemia vera marrows, as compared to normal. There was prominent stimulation of colony formation by erythropoietin, and the shape of the erythropoietin dose-response cruves appeared to be similar in both patients and controls. Anti-erythropoietin antibody reduced the number of CFU-E in cultures not containing added erythropoietin, but did not eliminate them. Dexamethasone (10(-9) M) caused a consistent increase in CFU-E in the patients' cultures. These studies provide evidence for functional erythropoietin and glucocorticosteroid receptor mechanisms on erythroid precursors in polycythemia vera. The observations are consistent with a concept of this disease as a disorder of hematopoietic stem cells in which peripheral erythrocytosis is caused by an expanded erythroid progenitor compartment which maintains responsiveness to hormonal modulation.

Antibodies↗

PubMed1977

Cytogenetic findings in polycythemia vera: a review and reevaluation.

Chromosomal aberrations reported in the disease course of patients with polycythemia vera are reviewed. Methodological pitfalls related to data collection, presentation and interpretation are pointed out. On the basis of the available information, it seems reasonable to conclude that chromosomal derangements are not specific to polycythemia vera and that clone formation is infrequent. The effect of therapy is manifested by an increase in the quantity of aberrations rather than in any specific type of aberration.

Bone Marrow↗

PubMed1975

32P-therapy in polycythemia vera.

A group of 52 consecutive patients with polycythemia vera was submitted to long-term therapy with radioactive phosphorus (32P). Initial phase of therapy induced complete remissions (normalization of hematogram; spleen not palpable) in 45% of the patients, and partial remissions in the remaining 55%. During maintenance therapy of the complete remission group, mean remission time was about 3.5 years. Individual remission times ranged between 1 and 6 years. In the group of patients with incomplete remission, mean remission time increased with the progression of the disease due to gradual development of "spent" -polycythemia. In patients with splenomegaly, remission time was negatively correlated to spleen size. In both groups the increment of annual accumulated dose averaged 2.4 mCi 32P. When considering polycythemia related causes of death only, mean survival time attained 12 years after initial treatment with 32P. Acute leukemia occurred in 2 patients (4%).

Adult↗

PubMed1978

Conversion of polycythemia vera to refractory anemia with hyperplastic bone marrow.

Clinical and morphologic findings in the conversion of treated polycythemia vera to pancytopenia with hyperplastic bone marrow (refractory anemia or pancytopenia with hyperplastic bone marrow) are described in light of our own observation. The nomenclature associated with this condition (pancytopenia, chronic erythroleukemia, preleukemia) is not uniform, whereas the morphologic findings are virtually identical. Some patients subsequently develop acute leukemia. The prognosis in cases of refractory anemia with hyperplastic bone marrow following polycythemia vera is, independent of the subsequent acute leukemia, invariably terminal.

Anemia, Aplastic↗