In a group of normal subjects going from sea level to approximately 16,000 feet we observed that very soon after arrival at high altitude there was hemoconcentration, as indicated by an increased red cell count and hematocrit, but a normal total red cell volume and a low plasma volume. This "apparent increase" in the number of red blood cells in the early days after arrival at high altitude is,...

introduction: chronic mountain sickness (cms) represents a syndrome of secondary polycythemia along with thrombocytopenia, altered hemorheology, pulmonary and systemic hypertension, and congestive heart failure, occurring due to hypobaric hypoxia-anoxia-induced erythropoiesis reported in both native mountain residents and new climbers after prolonged stays at high and extreme altitudes.case pre...

Thromboembolic events represent the main cause of morbidity and mortality in patients with polycythemia vera. Leukocytosis has been identified as an important risk factor for development of vascular thrombosis. A 47-year-old woman with polycythemia vera presented with pain and swelling in her right calf. She was scheduled to receive anagrelide which was effective on polycythemia and thrombocyto...

Decreased cardiac output, coronary blood flow, and systemic oxygen transport in polycythemia are attributed to increased blood viscosity and regarded as potentially harmful. We studied the effects of isovolemic polycythemia on these variables as well as on myocardial oxygen consumption and regional myocardial blood flow in 31 anesthetized dogs, seven with cannulated left main coronary arteries....

Polycythemia causes increased vascular production of nitric oxide (NO), most likely secondary to an effect of elevated vascular shear stress to enhance expression of endothelial nitric oxide synthase (eNOS). Because both polycythemia and increased eNOS expression are associated with chronic hypoxia-induced pulmonary hypertension, experiments were performed to test the hypothesis that increased ...

The hypoxic response is a stress response triggered by low oxygen tension. Hypoxia-inducible factors (HIFs) play a prominent role in the pathobiology of hypoxia-associated conditions, including pulmonary hypertension (PH) and polycythemia. The c-Jun N-terminal protein kinase (JNK), a stress-activated protein kinase that consists of two ubiquitously expressed isoforms, JNK1 and JNK2, and a tissu...

Comparison of results of red cell mass (RCM) measurement by 51Cr and 125I methods in 119 patients showed virtual equivalence. Both methods have an acceptable coefficient of variation (CV) that is < 5%. The 125I method is simpler and much less expensive. Unrealistically narrow "normal ranges" for RCM are likely to lead to misdiagnosis of polycythemia vera. Upper normal limits of 39 mL/kg (males)...

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...

Polycythemia vera (PV) is a chronic myeloproliferative disease that is often complicated with thromboembolism. However, aortic stenosis (AS) could be a manifestation of the cardiovascular complications of PV possibly through shear stress and atherosclerosis. We report a rare case of rapidly progressed AS in a patient with PV.

extramedullary hematopoiesis is characterized by the presence of hematopoietic tissue outside the bone marrow. extrathoracic extramedullary hematopoiesis is a rare and usually asymptomatic condition. we report a case of a 38-year-old female with paraspinal and presacral extramedullary hematopoiesis with polycythemia vera. clinical and laboratory evaluation, along with radiological and histopath...