Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Renal erythropoietin production is dependent on local oxygen content of blood which activates so called "oxygen sensors". Taking into consideration altered local renal blood supply in patients with arterial hypertension in the course of arteritis (HA) and from the other side contribution of the renin-angiotensin system in both pathogenesis of hypertension and regulation of erythropoietin production it seemed plausible to undertake this study. The aim of the study was to determine whether and in what extent patients with HA and healthy subjects differ in EPO secretion and whether EPO serum level is related in this patients to renin response to dietary sodium restriction and upright position of the body. 18 patients with HA and 12 healthy subjects were investigated. In all subjects haematocrit value, haemoglobin concentration, erythrocyte count, sodium, potassium, creatinine, iron, ferritin serum levels, total iron binding capacity, plasma renin activity (PRA), erythropoietin serum level and mean arterial blood pressure (MAP) were measured in basic conditions (normal sodium diet). Additionally PRA, EPO and MAP were measured after dietary sodium restriction to 10-20 mmol Na/24 hrs for three days and upright position of the body for three hours. Patients with HA had insignificantly lower serum EPO concentrations than healthy subjects and both studied groups did not differ in haematocrit value and determinants of iron metabolism except of significantly higher ferritin concentration in HA. After dietary sodium restriction and upright position of the body significant rise in PRA and no significant changes in EPO level were found in studied groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The role of erythropoietin in blood pressure regulation in patients with arteritis]. 130 May 62

The efficacy of once weekly subcutaneous erythropoietin (SC EPO) was evaluated by reviewing records of twelve continuous ambulatory peritoneal dialysis (CAPD) patients age 27-66 years after achieving a goal hematocrit (hct) greater than 30%. Patients had a mean hct of 22.8% (range: 19.1-29.5) and were placed on a thrice weekly SC EPO dose of 4000 international units (IU) (37-74 IU/KG, [mean of 57 IU/kg]) until a goal hct greater than 30% was achieved. This hct ranged from 30.8-37% (mean 33.2%) and was achieved in a mean of 11.5 weeks (range: 4.1-29 weeks). Patients were then maintained on the same SC EPO dose given only once weekly. 11/12 (92%) patients have maintained a mean hct of 34% (range: 29-38.4%) on once weekly SC EPO over a mean period of 14 weeks (range: 1.4-36 weeks). The mean serum ferritin was 484; only two patients required parenteral iron dextran therapy. One patient did not reach the goal hct due to poor compliance. There was no significant increase in blood pressure or in serum potassium level. We conclude that SC EPO is effective in treating anemia in these patients and can be given once weekly to maintain a hct greater than 30%.
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PMID:Once weekly subcutaneous erythropoietin is an effective maintenance therapy in the treatment of anemia of end stage renal disease in patients on CAPD. 168 Apr 48

Lymphocyte subpopulations were studied by immunofluorescence staining with monoclonal antibodies and laser flow cytometry in the blood of 23 hemodialysis patients before and after 3 months of treatment with recombinant human erythropoietin (rhEPO). Correction of anemia was accompanied by an increase in natural killer cells and a decrease in B lymphocytes. In the 11 patients (Group 1) with a baseline helper/suppressor (T4/T8) ratio greater than or equal to 2, the latter significantly decreased from 3.0 +/- 0.3 to 2.1 +/- 0.3 through both an increase in T8 cells and a decrease in T4 cells (p less than 0.005). Among the 12 patients with a pre-EPO T4/T8 ratio less than 2 (Group 2), no difference in T cell subsets was observed. The decrease in ferritin levels observed over the study period was not significant. In addition, the mean increase in hemoglobin levels during the first month of rhEPO therapy was greater in Group 2 than in Group 1 (1.1 +/- 0.3 vs. 0.6 +/- 0.3 g/dl, p less than 0.025). No change in any parameter was observed in eight control patients not receiving rhEPO. These results suggest that rhEPO can induce changes in lymphocyte subpopulations of hemodialysis patients through mechanism(s) yet to be clarified; conversely, the T4/T8 ratio might be a predictive factor for the erythropoietic response to rhEPO.
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PMID:Effects of recombinant human erythropoietin on T lymphocyte subsets in hemodialysis patients. 214 56

The dose of recombinant human erythropoietin (r-HuEPO) required to correct the anemia of end-stage renal disease (ESRD) varies among patients. The response to r-HuEPO is impaired if absolute or relative iron deficiency exists. Aluminum may cause a microcytic anemia in patients with ESRD, but the mechanism remains incompletely defined. Twenty-two patients in the Canadian Multicentre EPO trial were studied for 6 months. In this randomized double-blind placebo-controlled trial, free erythrocyte protoporphyrin (FEP) was used as an indicator of iron-deficient deficient erythropoiesis. The relationship of FEP to the estimates of iron availability (serum iron, transferrin saturation, ferritin) and iron utilization (corrected reticulocyte count, hemoglobin) was evaluated by multiple linear regression analysis. The effect of aluminum on FEP was evaluated by adjusting the statistical model for this variable. All patients were iron replete as assessed by serum ferritin. FEP was not related to serum aluminum before administration of r-HuEPO, but it was significantly correlated with aluminum in the treated group. In hemodialysis patients treated with r-HuEPO, the proportion of the variability explained by the parameters of iron utilization and iron availability was 0.27. The effect of aluminum increased this to 0.59. In hemodialysis patients not receiving r-HuEPO, the proportion of variability in FEP explained by the model increased from 0.16 to 0.28 by adjusting for aluminum. The data support the hypothesis that aluminum interferes with the bioavailability of stored iron for erythropoiesis and thus may result in a microcytic anemia in patients with ESRD or may blunt their response to r-HuEPO therapy.
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PMID:Bioavailability of iron in hemodialysis patients treated with erythropoietin: evidence for the inhibitory role of aluminum. 223 35

In order to clarify possible factors responsible for varying responses in uremic patients treated with recombinant human erythropoietin (rHuEPO), we determined the inhibitory effects of ten uremic sera on the erythroid progenitors (CFU-E) and erythroid bursts (BFU-E). We also measured plasma EPO titers, Fe, UIBC, ferritin, PTH-C, beta 2-microglobulin, and aluminum in all ten patients. The inhibitor of CFU-E but not BFU-E, was present in the serum of the single anemic patient whose recovery took longer after the administration of rHuEPO. He did not have such conditions as iron deficiency, excess of aluminum, or chronic inflammation. The remaining patients, who had no CFU-E or BFU-E inhibitors, were good responders to rHuEPO. In none of ten patients were there inhibitors of granulocyte-macrophage progenitors (CFU-GM) or any differences in the other parameters. Although the inhibitory factor of CFU-E can be overcome with a larger dose, its prior determination may be useful to set out minimal effective dose of EPO treatment.
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PMID:The inhibitory factors of hematopoiesis in chronic hemodialysis patients treated with recombinant human erythropoietin. 224 92

Recombinant human erythropoietin (R-Hu-EPO) was given to stable, long-term haemodialysis patients with haematocrit less than or equal to 25% who required no blood transfusions. Thirteen patients were initially given R-Hu-EPO at 24 U/kg i.v. at the end of each dialysis session, with a doubling of the dose every second week until a dose of 96 U/kg (n = 6) or 192 U/kg (n = 7) was reached after 8 weeks. In addition, three patients were given 24 U/kg for 2 weeks and subsequently 48 U/kg for 14 weeks. Median haematocrit increased from 19.4% (14.8-24.3) to 30.0% and 32.5% with 96 or 192 U/kg respectively. Starting 7 days after R-Hu-EPO a log dose-dependent increase in reticulocyte counts was noted. A consistent decrease in ferritin concentrations was observed despite oral supplementation of iron. A continuous rise in platelet counts was noted. Irrespective of blood-pressure status, predialysis blood pressure increased in six of nine patients who were not on antihypertensive medication; increased antihypertensive therapy was required in the others. A rise in bilirubin within the normal range was seen at the end of the study. No severe clinical side-effects occurred; specifically, there were no thrombotic episodes with the exception of clotting of two fistulae with known stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Recombinant human erythropoietin therapy in haemodialysis patients--dose determination and clinical experience. 311 64

Serum erythropoietic activity was determined in 32 patients with beta thalassemia major and intermedia. Quantitation was performed by an in vitro bioassay using rabbit erythroid precursor cells (CFU-E) either by colony assay or by 3H-thymidine uptake. 20 polytransfused beta-thalassemic major patients had erythropoietic activity (mean 89.3 +/- 36 milliunits/ml) which was not significantly different (p greater than 0.2) from normal individuals (51.3 +/- 32 milliunits/ml). 12 untransfused patients with beta thalassemia intermedia were found to have comparable serum erythropoietic activity (p greater than 0.01). These levels were much lower than those found in patients with aplastic anemia who had a comparable degree of anemia. We have shown that the low EPO activity in thalassemic patients was not due to experimental conditions (excess of ferritin, low transferrin) nor to specific inhibitors appearing in this disease. No correlation was found between the erythropoietic activity and sex or other clinical parameters of the patients such as severity of the anemia, splenectomy, iron chelation or transfusion therapy. 4 young thalassemic children (1-2 yr of age) studied had high erythropoietic activity ranging from 661 to 5793 milliunits/ml--significantly different from normal children of the same age. It is suggested, therefore, that a decrease in serum erythropoietin levels develops during the course of the disease.
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PMID:Erythropoietin activity in the serum of beta thalassemic patients. 378 74

Serotonergic mechanisms are partially responsible for changes in haemostasis and blood pressure rise in haemodialyzed patients treated with recombinant human erythropoietin (rHuEPO). Ketanserin--an antagonist of platelet and blood vessel serotonin receptors, given concomitantly to patients on rHuEPO therapy, prevents certain changes in haemostasis. Preliminary observations suggest that ketanserin also inhibits an increase in haemoglobin and haematocrit. So far there have been no reports on ketanserin affecting erythropoiesis. We studied an influence of the 2-week oral ketanserin administration on some haematologic parameters, serum erythropoietin concentration, blood pressure and relevant biochemical blood indexes in 15 haemodialyzed patients treated with rHuEPO for 32 weeks. We found a significant fall in serum EPO concentration (p < 0.005) measured with the ELISA technique that correlated positively (r = 0.629) with a decrease in erythrocyte count (p < 0.005). Haemoglobin concentration followed the same pattern (p < 0.005). The previously normal bleeding time prolonged significantly (p < 0.02) after ketanserin therapy. There were no changes in plasma iron and ferritin concentration, total iron binding capacity, transferrin saturation index, calcium, phosphorus and bilirubin concentration nor reticulocytosis. The decrement in EPO concentration did not affect peripheral blood platelet or leukocyte counts. The 14-day treatment with ketanserin did not influence arterial blood pressure in the patients. The study shows that ketanserin administered to haemodialyzed patients on long-term rHuEPO therapy induces a decrease in erythropoietin concentration and inhibits erythropoiesis. This phenomenon seems to result from diminished endogenous hormone synthesis caused by ketanserin.
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PMID:[Ketanserin decreases erythropoietin concentration in hemodialyzed patients on rHuEPO therapy]. 773 94

Chronic anemia of cancer can be corrected in approximately 50% of the cases by treatment with recombinant human erythropoietin (rHuEPO). Early prediction of responsiveness would avoid the emotional and financial burden of ineffective medical intervention. Eighty patients with chronic anemia of cancer undergoing treatment with rHuEPO (150 U/kg, 3 times per week by subcutaneous injection; after 6 weeks without response, 300 U/kg) participated in this study. Response was defined as a gain of at least 2 g/dL hemoglobin (Hb) within 12 weeks. Multivariate discriminant analysis and logistic regression analysis of response were performed on routine blood tests; serum levels of EPO, iron, ferritin, transferrin, and its receptor; World Health Organization (WHO) performance status; various cytokines; neopterin; stem cell factor; C-reactive protein; and alpha 1-antitrypsin. At baseline, none of these factors showed sufficient prognostic power. The following predictive algorithm was developed: (1) If after 2 weeks of therapy both the serum EPO level is > or = 100 mU/mL and Hb concentration has not increased by at least 0.5 g/dL, unresponsiveness of the patient is very likely (predictive power, 93%); otherwise, response may be predicted with an accuracy of 80%. (2) If both the serum level of EPO is less than 100 mU/mL and Hb concentration has increased by > or = 0.5 g/dL, response is highly probable (predictive power, 95%). (3) Alternatively, a serum ferritin level of > or = 400 ng/mL after 2 weeks of rHuEPO therapy strongly indicates unresponsiveness (predictive power, 88%), whereas a level less than 400 ng/mL suggests response in 3 of 4 patients.
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PMID:Prediction of response to erythropoietin treatment in chronic anemia of cancer. 788 86

Chemotherapy-induced anemia in children with cancer is usually of acute onset. To investigate an alternate treatment to transfusion (Tx), we undertook a phase I-II clinical trial of daily administrations of recombinant erythropoietin (rHuEPO). Patients with a hemoglobin (Hgb) value < 75 g/l were treated for 14 days in cohorts of 3 at escalating daily doses of 25, 50, 70, 80, 90, and 100 U/kg respectively. The maximum-tolerated dose was not encountered. Of 18 courses given to 15 children aged 0.5-18 years, 7 (39%) were associated with increased or stable Hgb levels (courses without Tx), while 11 (61%) were terminated by a Tx, without evidence of a dose-response relationship. Changes in mean Hgb levels and absolute reticulocyte counts were paralleled by those of mean white blood cell, platelet, and absolute neutrophil counts during the first 7 days and when the end-points of the study were reached. Numbers of circulating burst-forming units-erythroid remained low throughout courses without Tx. No cumulative increase of serially determined serum EPO levels was observed and serum ferritin levels were elevated in both groups of courses. We conclude that daily administration of rHuEPO were safe but ineffective in our trial. Recovery of chemotherapy-induced myelosuppression appeared to be the rate-limiting factor for the outcome, without evidence of an enhanced stimulation of erythropoiesis. The lack of a proliferative response of specific progenitor cells suggested a mechanism of transient primary resistance to rHuEPO.
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PMID:Recombinant erythropoietin in acute chemotherapy-induced anemia of children with cancer. 775 97


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