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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spurious polycythemia is not a primary disease process. It sometimes may be nothing more than an unusual, but normal, physiologic state. In other instances, however, it is associated with a true abnormality of plasma volume. Although there is probably overlap between these extremes, differentiation of these subclasses may be of prognostic significance. The elevation in hematocrit bears no relation to morbidity, and, because there is no evidence of abnormal erythroid proliferation, reduction of red cell volume via phlebotomy or myelosuppression is inappropriate. Nonhematologic parameters, particularly hypertension, are the major factors of significance in the substantial cardiovascular morbidity in spurious polycythemia, and they demand attentive and aggressive management.
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PMID:Spurious polycythemia. 119 27

Erythropoietin (EPO) is the main regulatory hormone for the control of erythropoiesis. EPO leads to enhanced mitosis and differentiation of erythroid precursors in the bone marrow. The major stimulus for EPO-formation is anaemia of various origin, resulting in an exponential relation between EPO levels and a decrease in haematocrit. Another important stimulus for increased EPO production is a fall of the arterial oxygen tension caused by either cardiopulmonary disorders or by a decrease of the oxygen tension in the inspiratory gas. Human erythropoietin was first isolated and purified from a large amount of urine of patients with aplastic anaemia. After the EPO gene had been cloned and expressed, biotechnically produced recombinant human erythropoietin (rHu-EPO) became available for clinical trials. EPO deficiency appears to be the major cause of renal anaemia, and hence the treatment of these patients is the most important indication for clinical use. Encouraging results in patients whose anaemia is not of renal origin have also been reported, using treatment with rHu-EPO. In preoperative autologous blood donation programmes prior to elective surgery, rHu-EPO therapy improved the amount of donated blood and ameliorated the decrease of haematocrit values. Side effects such as hypertension, thrombosis, hypercalcaemia, elevated liver enzymes were rare and were mostly related to the underlying disease.
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PMID:[Erythropoietin--physiology and therapeutic potentialities]. 148 69

Chronic renal failure is almost invariably accompanied by symptomatic anemia. It has been demonstrated that the primary cause of this anemia is inadequate production of erythropoietin by the diseased kidneys. The isolation of erythropoietin, followed by the cloning and expression of the human erythropoietin gene, made possible clinical trials of rHuEPO in uremic patients. rHuEPO produced dramatic increases in the hematocrit in almost all patients treated and also ameliorated many symptoms, such as lethargy, dizziness, and poor appetite, that had long been attributed to the effect of uremic toxins. Adverse effects of treatment with rHuEPO noted in the early clinical trials included hypertension, seizures, arteriovenous fistula or shunt thrombosis, and hyperkalemia. Further study of rHuEPO has shown that many of these side effects may be no more frequent in patients receiving rHuEPO than in other uremic patients not receiving rHuEPO. Reduction of the rHuEPO dosage and subcutaneous administration produce less rapid increases in the hematocrit and may lessen the incidence and severity of these side effects. rHuEPO therapy places great demands on both the body's iron stores and the capacity to rapidly transfer iron from storage sites to the erythroid progenitor cells. Thus, almost all patients treated with rHuEPO become iron deficient and require oral or parenteral iron replacement. Response to rHuEPO in uremic patients is diminished if the anemia is complicated by iron deficiency, inflammatory disorders, aluminum overload, or deficiency of folate or vitamin B12. rHuEPO therapy is safe and effective in the treatment of the anemia of chronic renal failure. The use of rHuEPO leads to enhanced quality of life and eliminates the need for red cell transfusions. In addition to hemodialysis patients, predialysis patients and those on CAPD benefit from and are candidates for rHuEPO therapy.
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PMID:Anemia of renal failure. Use of erythropoietin. 157 66

Sixteen patients with relapsed non-Hodgkin's lymphoma underwent autologous bone marrow transplantation and infusion of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF). Treatment consisted of involved-field radiotherapy, cyclophosphamide 60 mg/kg/d intravenously (IV) for 2 days, and fractionated total body irradiation (1,200 cGy). Autologous bone marrow was thawed and infused IV, followed 3 hours later by the first infusion of IV rhGM-CSF 11 micrograms/kg/d over 4 hours. Infusions of rhGM-CSF were continued daily until either both neutrophil count exceeded 1,500/microL and platelet count exceeded 50,000/microL, or until 30 days after marrow re-infusion. Toxicities encountered were mild and included fever, chills, hypertension, alopecia, rash, diarrhea, stomatitis, myalgias, and synovial (knee) effusions. Neutrophil recovery greater than 500/microL occurred a median of 14 days (range, 9 to 30 days) after marrow infusion, significantly earlier than in a comparable group of historic controls who recovered counts at a median time of 20 days (range, 12 to 51 days) (P = .00002). Median time to self-sustaining platelet counts greater than 20,000/microL was 23.5 days (range, 12 to 100 days), comparable with the historic group (P = .38). One bacteremia (central venous catheter exit site infection with Staphylococcus epidermidis) and one local infection (Giardia lamblia in stool) occurred. Patients received a median of 11.4 (range, 4.4 to 20.2) x 10(4) colony-forming unit granulocyte-macrophage (CFU-GM) progenitors per kg. Stem cell progenitors CFU-GM, CFU-granulocyte, erythroid, monocyte, megakaryocyte (CFU-GEMM), and burst-forming unit-erythroid (BFU-E) were detected in the bone marrow as early as 7 days after marrow re-infusion, and increased in proportion to peripheral blood counts, but by 30 to 60 days still remained much lower than before transplant. Neutrophils transiently decreased in 13 of 16 patients (median decrease, 42%) within 24 to 72 hours of discontinuing rhGM-CSF infusions. These data suggest that rhGM-CSF therapy enhances neutrophil recovery by forcing stem cells to produce mature elements at an enhanced rate but may not affect marrow stem cell and early progenitor population sizes.
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PMID:Recombinant granulocyte-macrophage colony-stimulating factor after autologous bone marrow transplantation for relapsed non-Hodgkin's lymphoma: blood and bone marrow progenitor growth studies. A phase II Eastern Cooperative Oncology Group Trial. 185 94

Erythrocytosis and microcytosis have been described in strains of genetically hypertensive rats and in essentially hypertensive humans. Published discussion of these phenomena has centered around their relationship to observed alterations in ionic transport and the pathogenesis of hypertension. In presenting data for another strain of spontaneously hypertensive rats in which these findings are exhibited, we note that erythroid cell size decreases concurrently with the increase in cell numbers so that the hematocrit and the mean corpuscular hemoglobin concentration remain constant. Data from the literature support the hypothesis that erythroid cell size is inversely proportional to cell count in a large number of species. Erythrocytosis, as it develops in the neonatal rat, is a consequence of the marked immaturity of this species at birth. Erythrocytosis in the spontaneously hypertensive rat is not due to a difference in the affinity of its hemoglobin for oxygen or to significant tissue anorexia. Microcytosis in the spontaneously hypertensive rat is the consequence of a continuation of the linear volume decrease with age of its erythroid cells seen in the normotensive animals and may be accounted for by the production of smaller cells with concomitant regulation of individual cell volume.
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PMID:Inverse changes in erythroid cell volume and number regulate the hematocrit in newborn genetically hypertensive rats. 194 11

Anemia is a common complication of multiple myeloma. It resolves early in the disease if chemotherapy induces a complete remission, but persists if the disease progresses, causing disabling symptoms and often requiring blood transfusions. We treated 13 patients with myeloma-associated anemia by administering recombinant human erythropoietin three times a week for six months. Eleven patients (85 percent) had steady increases in hemoglobin levels and eventual correction of the anemia. Their symptoms of anemia subsided, and they reported a heightened sense of well-being. No patient had any adverse side effects, particularly episodes of hypertension. Monitoring of the serum M component showed a predominantly stable tumor load without apparent interaction between the underlying disease and the response to erythropoietin therapy. The number of erythroid burst-forming units in the bone marrow and peripheral blood and the level of erythropoiesis in bone marrow smears increased significantly during therapy. Pretreatment serum levels of erythropoietin were higher in the patients who did not respond and in those who required more than two months of treatment before they responded. Serum iron, ferritin, and transferrin concentrations reflected responses to treatment. We conclude that recombinant human erythropoietin is a promising therapeutic tool for treating myeloma-associated anemia.
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PMID:Erythropoietin treatment of anemia associated with multiple myeloma. 198 68

During the study of an inbred strain of Wistar rats which spontaneously develop hypertension when they reach a weight of approximately 150 g, it was found that these animals also develop an erythrocytosis. A significant increase in red cell count was observed in spontaneously hypertensive (SH) rats (8-11 x 10(6) RBC/mm(3)) when compared with normotensive rats (6-7 x 10(6) RBC/mm(3)) of the same strain. This increase in red cell count paralleled the increase in body weight and the rise in blood pressure. Since the plasma volume, as measured with labeled albumin was normal, there was an absolute increase in red cells. The hematocrit and hemoglobin content of the blood measured in SH rats were only slightly greater than those found in normotensive rats. However, the mean cell volume (MCV) of the red cells in the SH rats was 45-47 mu(3) as compared with 51-53 mu(3) in normotensive rats.A fourfold increase in 24 hr (59)Fe incorporation into the red cells was found in the SH rats when compared with normotensive controls. The bone marrow of the SH rats showed erythroid hyperplasia. When the SH rats were treated with alpha-methyldopa (Aldomet 200 mg/kg daily, i.p.) the red cell count fell in parallel with the drop in blood pressure. No change in red cell count or blood pressure was observed in normotensive rats treated in the same manner. The erythropoietin titer was high in SH rats, and was undetectable in normotensive rats. These observations suggest a direct relationship between the hypertension and the erythrocytosis mediated by erythropoietin; both are genetically controlled.
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PMID:Erythrocytosis in spontaneously hypertensive rats. 501 Nov 7

Epoetin alfa is a recombinant form of erythropoietin, a glycoprotein hormone which stimulates red blood cell production by stimulating the activity of erythroid progenitor cells. This review discusses the use of the drug in the management of anaemia in diseases often associated with advancing age [renal failure, cancer, rheumatoid arthritis (RA) and other chronic diseases, and the myelodysplastic syndromes (MDS)] and in surgical patients. Intravenous and subcutaneous therapy with epoetin alfa raises haematocrit and haemoglobin levels, and reduces transfusion requirements, in anaemic patients with end-stage renal failure undergoing haemodialysis or peritoneal dialysis. The drug is also effective in the correction of anaemia in patients with chronic renal failure not yet requiring dialysis and does not appear to affect renal haemodynamics adversely or to precipitate the onset of end-stage renal failure. Response rates of 32 to 82% with epoetin alfa therapy have been reported in patients with anaemia associated with cancer or cytotoxic chemotherapy. Limited data in patients with anaemia associated with RA show correction of anaemia after epoetin alfa treatment. Response rates to the drug of 0 to 56% have been noted in patients with MDS. Epoetin alfa also reduces anaemia, increases the capacity for autologous blood donation and reduces the need for allogeneic blood transfusion in patients scheduled to undergo surgery. Hypertension occurs in 30 to 35% of patients with end-stage renal failure who receive epoetin alfa, but this can be managed successfully with correction of fluid status and antihypertensive medication where necessary, and is minimised by avoiding rapid increases in haematocrit. Although vascular access thrombosis has not been conclusively linked to therapy with the drug, increased heparinisation may be required when it is administered to patients on haemodialysis. Epoetin alfa does not appear to exert any direct cerebrovascular adverse effects. Thus, epoetin alfa is a well established and effective therapy for the management of anaemia associated with renal failure. It also improves haematocrit and quality of life in patients with anaemia associated with cancer or chemotherapy. Epoetin alfa increases the capacity for blood donation and reduces the decrease in haematocrit seen in patients donating autologous blood prior to surgery. It also reduces, but may not eliminate, the need for allogeneic blood transfusion.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Epoetin alfa. A review of its clinical efficacy in the management of anaemia associated with renal failure and chronic disease and its use in surgical patients. 757 84

The success of maintenance haemodialysis in the 1960s was blighted by the problem of anaemia. Treatment with iron, folic acid, androgens and transfusions did no more than minimize its effects. The need for a renewable source of erythropoietin was appreciated very early but the hope took 25 years to realize. Cloning and expression of the human gene was achieved in 1984 and clinical trials planned even before the descriptions of the recombinant hormone were published. The Amgen material was tested in parallel studies in Seattle and England and by the end of 1986 the efficacy of recombinant human erythropoietin (r-HuEPO) given in large intravenous bolus doses in reversing the anaemia of uraemia was established. The benefits were immediately obvious: relief from transfusion dependence was the unequivocal evidence but the effect on 'wellbeing' though subjective was remarkable. Large clinical trials were completed in Europe and the USA so that r-HuEPO was licensed as a therapeutic drug less than two years later. The pilot studies flagged a number of key issues: hypertension, sometimes with encephalopathy, occurred in patients whose blood pressure was labile before treatment; vascular access failure seemed more frequent and hyperkalaemia was thought to reflect less efficient dialysis. Failure to respond focused attention on iron balance as well as on factors such as infection, aluminium, and hyperparathyroidism. A more clear understanding of the pathogenesis of the anaemia of uraemia was made possible by dissection of the specific effects of the exogenous erythropoietin on erythroid function.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Historical review on the use of recombinant human erythropoietin in chronic renal failure. 764 3

Erythropoietin (Epo) is a glycoprotein hormone responsible for the control of the proliferation and differentiation of cells of erythroid lineage. Recombinant erythropoietin (rHuEpo) is widely used as a pharmacological agent for the treatment of the anaemia of renal failure. Efficacy of rHuEpo and its superiority over blood transfusions have been proven in large multicentre trials. The most important side-effect of the therapy is the increase of BP which is observed in approximately 30-35% of dialysis patients receiving rHuEpo. It appears that the haemodynamic resetting that occurs with partial correction of anaemia may be inappropriate resulting in an altered vascular resistance in relation to the cardiac output. This is in turn due to the combination of increased blood viscosity and loss of hypoxic vasodilatation. Both these factors, however, cannot account completely for the rise in vascular resistance, and therefore the possibility of a direct and/or hormonally-mediated vasopressor effect of rHuEpo has recently been raised. Moreover, scarce information exists on the possible involvement of endogenous erythropoietin in the pathogenesis of arterial hypertension and haematological disturbances observed in primary and some secondary forms of hypertension.
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PMID:Erythropoietin and hypertension. 775 79


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