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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urinary and proximal tubular iron are increased after subtotal nephrectomy, and iron depletion has been shown to be beneficial in proteinuric models of chronic renal disease in rats. In this study, iron depletion by low iron pair-fed diet and periodic phlebotomy was induced for 6 months in rats with partial (5/6) nephrectomy, resulting in a reduction in hematocrit and serum iron in all iron-deficiency subgroups. Tubular iron, assessed by energy dispersive analysis and electron microscopy, was reduced in quantity but not number of iron-containing lysosomes only within 1 subgroup of severe iron deficiency (p < 0.05). There was no improvement in serial isotopic glomerular filtration rate measurements, urinary protein and transferrin excretion, tubular damage scores, serum creatinine, or measures of reactive oxygen species (ROS) generation. In a subgroup of rats with no supplementation of sulfhydryl amino acids (cysteine and methionine) which can act as ROS scavengers, iron deficiency increased urinary protein excretion (213.3 +/- 23.0 mg/24 h, mean +/- SEM, vs. 87.4 +/- 16.1, p < 0.001), urinary transferrin excretion (p < 0.05), kidney weight (p < 0.05) and tissue malondialdehyde, a lipid peroxidation product (0.78 +/- 0.16 nmol/mg protein vs. 0.57 +/- 0.19, p < 0.05), consistent with increased ROS generation. Hence, no beneficial effect of iron-deficiency was demonstrated by any measure of structure of function in the remnant kidney, and it may enhance damage if sulfhydryl repletion is not provided.
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PMID:Iron depletion in the remnant kidney. 747 24

Serum ferritin concentration correlates with tissue iron stores in humans, horses, calves, dogs, and pigs but not in rats. Because serum iron and total iron-binding capacity can be affected by disorders unrelated to iron adequacy (such as hypoproteinemia, chronic infection, hemolytic anemia, hypothyroidism, and renal disease), serum ferritin is probably the most reliable indicator of total body iron stores in larger species. To test the hypothesis that serum ferritin might be correlated with tissue iron levels in cats, we developed a quantitative enzyme-linked immunosorbent assay that uses two monoclonal antibodies in a sandwich arrangement to measure feline serum ferritin. The recovery of purified ferritin added to feline sera ranged from 94% to 104%; the within-assay coefficient of variability was 8.4%, and the assay-to-assay variability was 13.2%. Mean serum ferritin from 40 apparently healthy cats was 76 ng/ml (SD = 24 ng/ml). Serum ferritin concentration was significantly correlated (P < 0.001, n = 101, r = 0.365) with the nonheme iron in the liver and spleen (expressed as milligrams of iron per kilogram of body weight), as determined by Pearson product-moment correlation analysis. Because serum iron can decrease in diseases other than iron deficiency, the combination of serum iron and serum ferritin should provide sufficient evidence to differentiate anemia of chronic inflammation from anemia of iron deficiency in the cat.
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PMID:Enzyme-linked immunosorbent assay to measure serum ferritin and the relationship between serum ferritin and nonheme iron stores in cats. 786 83

The optimal method for diagnosing iron deficiency in end-stage renal disease is an area of controversy. This study compared the use of zinc protoporphyrin (ZPP) with the use of conventional tests for determination of iron deficiency when evaluating the need for intravenous iron therapy in hemodialysis patients maintained on erythropoietin (EPO). A baseline survey was performed in all hemodialysis patients at the Baumritter Kidney Center (Bronx, NY), measuring ZPP, ferritin, transferrin saturation (TSAT), mean corpuscular volume, and hematocrit. Patients with ZPP > or = 90 mumol/mol heme or ferritin less than 100 ng/mL were considered likely to be iron deficient and were treated with 1,000 mg of intravenous iron dextran over 10 hemodialysis treatments. The positive predictive values of ferritin and ZPP for predicting a response to intravenous iron dextran were similar (73% v 83%, respectively; two-tailed, P = 0.48). To determine the sensitivity and specificity of the tests, patients were divided into two groups at the end of the study period: those in whom iron therapy was required (n = 23) (patients treated with intravenous iron dextran who had a 5% increase in hematocrit or a decrease in erythropoietin dose of > or = 2,000 U/treatment) and those in whom iron therapy was not required (n = 24) (patients either treated with intravenous iron dextran without a response [n = 9] or patients whose initial ZPP and ferritin levels were not suggestive of iron deficiency and who maintained a stable hematocrit and erythropoietin dose during the study period [n = 15]).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The utility of zinc protoporphyrin for predicting the need for intravenous iron therapy in hemodialysis patients. 787 20

Recombinant human erythropoietin (EPO) is an effective and safe therapy for correction of anemia in end-stage renal disease (ESRD). Clinical trials reported to date suggest that EPO improves anemia in over 90% of hemodialysis patients with anemia (Eschbach 1989). Factors which have been identified that appear to inhibit the effectiveness of EPO are infection [Muirhead N et al. 1990], iron deficiency, hyperparathyroidism, aluminium excess [Casati 1991] and persistent GIT bleeding. The development of reticulocytosis in response to EPO in the absence of a rise in hematocrit should alert the clinician to the possibility of either hemolysis or occult blood loss. We present a case in which, despite the development of a reticulocytosis of 5% in response to EPO and the absence of hemolysis, we had difficulty in identifying the presumed source of blood loss.
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PMID:Chronic occult intra-alveolar hemorrhage: a rare cause of failure to respond to erythropoietin. 800 33

In order to study the relationship between erythropoiesis and serum ferritin (SF) during erythropoietin (rHuEPO) therapy in the anaemia of end-stage renal disease (ESRD), 19 patients were followed without iron supplementation and at a fixed dose of the drug (40 U/kg). Twelve patients failed to attain the target haemoglobin (Hb) value, 7 of whom due to the appearance of iron deficiency. Erythropoiesis, as measured by the serum transferrin receptor concentration, increased from 12 to 120% of the basal value. This increment was not constantly associated with a proportional rise of Hb or reticulocyte count. SF decreased exponentially from a median value of 221 micrograms/dl (range 42-470) to a median value of 54 micrograms/dl (range 20-172). Halving of the basal SF value (SF-T50) was reached at the 18th-95th day of therapy (median = 43), representing a iron shift of 3.4-11.6 mg/day (median = 5.4). SF-T50 was not correlated with the Hb increase, but with that of erythropoiesis (r = 0.78; p = 0.003). The minimum SF (MSF) value attained was not correlated with the appearance of iron deficiency. The conclusion is that the rate of SF decrease during rHuEPO in ESRD is a reliable measure of iron mobilisation for erythropoiesis, but not for haematologic response. The MSF value reached during therapy is not representative of available iron for erythropoiesis.
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PMID:Variations in erythropoiesis and serum ferritin during erythropoietin therapy for anaemia of end-stage renal disease. 823 68

Outcomes goals in managing anemia in end-stage renal disease (ESRD) with epoetin alfa and other therapies are illustrated with a case study. Anemia is common in patients with ESRD undergoing hemodialysis; the cause is primarily a reduction in the secretion of erythropoietin. Multiple coexisting factors, such as iron deficiency and blood loss, also contribute. Outcomes goals include decreasing blood transfusions, increasing physical performance, improving cardiovascular and cognitive function, enhancing overall well-being, and achieving self-sufficiency. The potential to achieve these goals has been linked to the attainment of an optima, hematocrit and hemoglobin concentration with epoetin alfa therapy. Once epoetin alfa is begun, safety and effectiveness should be monitored and attainment of outcomes goals assessed. Supplemental iron, folate, and cyanocobalamin may be necessary, as may management of the underlying inflammatory process. The pharmacist can help optimize outcomes by conducting drug-use evaluations, monitoring laboratory test values and drug dosages, assessing drug effectiveness, and counseling patients. A case study of a 67-year-old woman with diabetes mellitus and ESRD who was placed on hemodialysis is presented as an example of how the pharmacist can help optimize outcomes. Opportunities for pharmacists in outcomes management in patients with ESRD-associated anemia include monitoring epoetin alfa therapy, counseling patients, and working with the renal team.
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PMID:Health care outcomes case study: anemia in end-stage renal disease. 884 42

One of the important components of successful anemia therapy in patients with end-stage renal disease (ESRD) treated with recombinant human erythropoietin is the maintenance of adequate available iron. To accomplish this task, iron status must be serially monitored and supplemental iron administered as required. Among nonuremic subjects, the body's iron supply is tightly conserved, and iron deficiency usually develops only when chronic blood loss occurs. In patients with ESRD, iron deficiency occurs more frequently, because of increased external losses of iron, decreased availability of the body's storage of iron, and perhaps a deficit in intestinal iron absorption. Detecting iron deficiency in these patients can be difficult because of the inaccuracy of available diagnostic tests. The goals of iron therapy in ESRD include the prevention of iron deficiency by chronically supplementing iron, and the prompt treatment of overt iron deficiency. Oral iron supplements are inexpensive and safe, but poor patient compliance and reduced intestinal absorption may limit their effectiveness. Intravenous iron supplements have a greater efficacy then oral iron, which must be weighed against the small risk of allergic reactions. We present strategies for using the various diagnostic tests and treatment modalities to effectively manage iron supply for predialysis, hemodialysis, and peritoneal dialysis patients.
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PMID:Iron management in end-stage renal disease. 929 80

Careful evaluation of iron status is of pivotal importance in end-stage renal disease patients before and during r-HuEPO therapy. Absolute (ferritin < 100 micrograms/l) and functional (ferritin normal or supranormal, transferrin saturation < 20%, hypochromic red blood cell [RBC] > 5%) iron deficiency are the main reasons for r-HuEPO hyporesponsiveness. Adequate iron supplementation allows significant reduction of r-HuEPO dosage and costs. Oral iron supplementation is recommended for predialysis and peritoneal dialysis patients with serum ferritin > 100 micrograms/l, whereas i.v. iron supplementation is the therapy of choice in hemodialysis patients. However, neutrophil impairment and other possible side-effects (e.g. cardiovascular complications, malignancy) as a result of i.v. iron therapy suggest that overtreatment with i.v. iron should be avoided.
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PMID:Erythropoietin and iron. 934 97

The treatment efficacy of erythropoietin (EPO) in end-stage renal disease (ESRD) can be limited by deficiencies of iron, folate, or vitamin B12, by hyperparathyroidism, or by aluminum intoxication. Since EPO costs are significant, this study attempted to determine the cost-effectiveness of performing a panel of screening tests for anemia before starting EPO. Anemia screening was performed prospectively in 48 new-onset ESRD patients at the Ralph H. Johnson Veterans Affairs Medical Center before EPO treatment was started. Serum iron, transferrin, folate, vitamin B12, parathyroid hormone, and aluminum levels were determined, and transferrin saturation (Tfsat) was calculated at the first dialysis session. At presentation for dialysis, the mean hematocrit was 0.264 +/- 0.036 and the mean blood urea nitrogen was 32 +/- 2 mmol/L. Eighteen patients (37.5%) had a serum iron level lower than 7 micromol/L, suggesting iron deficiency. Twenty-five patients (52%) had Tfsat less than 0.20, consistent with overt iron deficiency. No patient was found to be vitamin B12 deficient, to be aluminum intoxicated, or to have significant hyperparathyroidism. One patient had folate deficiency. A cost-effectiveness analysis was performed assuming that (1) EPO would be given at an average starting dose of 6,000 U/wk at a cost of $14/2,000 U of EPO; (2) that without screening 1 month would elapse before a poor response was identified; and (3) that the failure to treat aluminum intoxication and hyperparathyroidism or to replete iron, vitamin B12, or folate deficiency would significantly impair the response to EPO. The Tfsat screen had a cost-effectiveness ratio of 0.2019, saving approximately $5.00 in EPO use for each dollar of test administration. All other screens had cost-effectiveness ratios greater than 1.0, indicating that their testing costs exceeded dollar savings in EPO use. In conclusion, iron deficiency is common in anemic patients starting dialysis, but other causes of anemia are not. It is imperative that current clinical practices be influenced by cost-effectiveness considerations. Given the cost of laboratory screens, and the relative ineffectiveness of the other screens examined here to identify factors known to impair the response to EPO, anemia screening before initiating EPO therapy should be limited to tests to identify iron deficiency.
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PMID:A cost-effectiveness analysis of anemia screening before erythropoietin in patients with end-stage renal disease. 915 97

Recombinant erythropoietin (rHuEPO) is well established in the management of anemia of chronic renal disease. However, a number of clinical issues, including the best laboratory indicators of an imminent marrow response to rHuEPO replacement, the ideal measurements to detect masked iron deficiency, and optimal methods of iron replacement, remain unanswered. To investigate these issues, studies were performed in anemic chronic hemodialysis patients. A number of standard hematologic measurements in addition to automated reticulocyte counts (Sysmex R-1000) and serum transferrin receptors (TfR) were obtained in these patients. A response to initiation of rHuEPO administration could be predicted if the serum TfR concentration was less than 6 mg/L (normal, 3.8 to 8.5 mg/L). In patients on rHuEPO, an imminent hemoglobin response to an increased rHuEPO dose could be predicted after 1 week based on a greater than 20% increase from baseline in the serum TfR or absolute reticulocyte count, with a sensitivity of 92%. In patients on rHuEPO replacement with serum ferritin levels greater than 30 microg/L, none of the panel of tests, including serum TfR, reliably detected masked iron deficiency. In a long-term study over 5 months in patients on a stable maintenance dose of EPO, a gradual decline in total body iron occurred, even in subjects with initial adequate iron stores, and despite taking 50 mg elemental iron daily as oral ferrous sulphate. The serum TfR is useful for predicting a hemoglobin response when initiating rHuEPO therapy, and combined with automated reticulocyte counting it is valuable for predicting a hemoglobin response when increasing the dose of rHuEPO. The serum TfR loses its specificity for detecting tissue iron deficiency in patients on maintenance rHuEPO therapy because of increased erythropoiesis, which itself raises serum TfR levels.
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PMID:Markers of masked iron deficiency and effectiveness of EPO therapy in chronic renal failure. 932 69


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