Although polycythemia commonly occurs in hypoxic patients, most hemodynamic studies of polycythemia have been done in the normoxemic state. We studied the combined effects of polycythemia and hypoxia. In 11 splenectomized, anesthetized dogs, hematocrit was increased from 42.6 ± 1.2 to 65.5 ± 0.6% (SEM) by isovolumic exchange transfusions with fresh canine packed RBC's. Studies were conducted du...

With an increasing incidence of obesity, sleep apnea and other chronic pulmonary diseases, the prevalence of secondary polycythemia is expected to rise in adults. Phlebotomy is commonly utilized in the management of secondary polycythemia. Although supported by a number of studies demonstrating a transient improvement in cardiovascular and cerebrovascular physiology, the benefit of phlebotomy i...

Acute reduction in red cell volume (RCV) without significant alterations of blood volume in 22 patients with severe polycythemia secondary to cyanotic congenital heart disease resulted in a decrease in peripheral vascular resistance and an increase in stroke volume, systemic blood flow (SBF), and systemic oxygen transport. These changes are probably related to the decreased blood viscosity and ...

1. Najean Y, Rain JD, Billotey C. Epidemiological data in polycythaemia vera: a study of 842 cases. Hematol Cell Ther 1998; 40:159-65. 2. Fernandez-Luna JL, Silva M, Richard C, Sanz C, Benito A. Pathogenesis of polycythemia vera. Haematologica 1998; 83:150-8. 3. Barosi G. Pathogenesis of polycythemia vera: do we have the right pieces to the puzzle? Haematologica 1998; 83:97-8. 4. Barbui T, Fina...

BACKGROUND Polycythemia vera is a clonal hematopoietic stem cell disorder in which the JAK2 V617F mutation is observed in >95% of patients, but an as yet unidentified process appears to initiate the clonal expansion of hematopoiesis. Because microRNA regulate hematopoietic differentiation, we hypothesized that dysregulated expression of microRNA may contribute to the pathophysiology of polycyth...

The occurrence of arterial hypoxia with polycythemia usually results from some known type of pulmonary disease or from an abnormal communication between the right and left sides of the circulation. Although arterial oxygen unsaturation has been observed in patients with polycythemia vera (1-4), it is usually of only mild degree. Recently, Newman, Feltman, and Devlin (5) found polycythemia and a...

We analyzed the effect of hydroxyurea on the JAK2V617F allelic ratio (%JAK2V617F), measured in purified blood granulocytes, of patients with polycythemia vera and essential thrombocythemia. Thirty-six patients were examined sequentially prior to and after start of hydroxy-urea therapy (8 polycythemia vera, 17 essential thrombocythemia), or while remaining untreated (2 polycythemia vera, 9 essen...

Polycythemia literally means too many cells in the blood and is initially classified into relative and absolute. In absolute polycythemia the red cell mass is increased where as in relative it is not. Since automated blood counts are done commonly many asymptomatic patients with polycythemia are detected. Hematocrit value above 51% for males and 48% for females requires further evaluation. Valu...

Rats with polycythemia induced by exposures to simulated high altitudes developed a significantly higher incidence of endocarditis following intravenous bacterial injections than rats with cobalt polycythemia or ground level controls. No increase occurred in altitude rats when polycythemia was prevented by repeated bleedings. These findings suggest that both polycythemia and hypoxia are necessa...