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)

To evaluate the effects of erythropoietin (EPO) therapy on the lipid profile in end-stage renal failure, we undertook a prospective study in patients on both hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). One hundred and twelve patients (81 HD, 31 CAPD) were enrolled into the study. Lipid parameters [that is, total cholesterol and the LDL and HDL subfractions, triglycerides, lipoprotein (a), apoproteins A and B], full blood count, iron studies, B12, folate, blood urea, aluminium and serum parathyroid hormone were measured prior to commencement of EPO therapy. Ninety-five patients were reassessed 5.2 +/- 0.3 (mean +/- SEM) months later and 53 patients underwent a further assessment 13.1 +/- 0.6 months after the commencement of EPO, giving an overall follow-up of 10.0 +/- 0.6 months in 95 patients. As expected, EPO treatment was associated with an increase in hemoglobin (7.7 +/- 0.1 vs. 9.9 +/- 0.2 g/dl; P < 0.001) and a decrease in ferritin (687 +/- 99 vs. 399 +/- 69 micrograms/liter; P < 0.01). A significant fall in total cholesterol occurred (5.8 +/- 0.1 vs. 5.4 +/- 0.2 mmol/liter; P < 0.05) in association with a fall in apoprotein B (1.15 +/- 0.04 vs. 1.04 +/- 0.06; P < 0.05) and serum triglycerides (2.26 +/- 0.14 vs. 1.99 +/- 0.21; P < 0.05) during the course of the study. Other lipid parameters did not change, although there was a trend towards improvement.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of erythropoietin therapy on the lipid profile in end-stage renal failure. 819 94

Findings reported are for a subset of African American subjects, residing in the urban area of Washington, D. C., who participated in a Program Project designed to study nutrition, other factors, and the outcome of pregnancy. Fasting blood samples, drawn during each trimester of pregnancy and at delivery, were screened for concentrations of cocaine, phencyclidine (PCP) and marijuana. Since substance abusers are expected to consume inadequate diets, these samples were also analyzed for serum folate, vitamin B12, ferritin and ascorbic acid. Data for these biochemical variables were compared for subjects whose serum values for drugs were either above or below the drug screening threshold concentrations established by ADAMHA/NIDA. Pearson's correlations were used to determine relationships between pregnancy outcome variables and maternal serum drug concentrations. Blood samples drawn at delivery showed higher maternal: cord ratios (mean +/- SEM) for marijuana (3.3 +/- 2.2) and PCP (2.9 +/- 1.0) than for cocaine (1.0 +/- 0.2). The subjects whose serum values were above the ADAMHA/NIDA ranges for marijuana, PCP and cocaine had concentrations of folate and ferritin that were significantly less than those of subjects with lower serum drug levels (P < or = 0.05). High maternal serum concentrations of illicit drugs were accompanied by a significant increase in leukocyte count (P < or = 0.05). The level of maternal cocaine during the third trimester was inversely correlated with birthweight (r = -0.29; n = 52; P = 0.038) and head circumference (r = -0.28; n = 52; P = 0.047).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relationships of serum illicit drug concentrations during pregnancy to maternal nutritional status. 820 48

We studied 38 patients (9 haemodialysis, 18 peritoneal dialysis, 11 advanced renal failure) over the first 12 weeks of erythropoietin therapy. In 14 iron-overloaded patients (ferritin > 500 micrograms/l the haemoglobin (+/- SEM) increased from 6.74 +/- 0.27 to 9.85 +/- 0.36 g/dl (P < 0.0001) entirely by mobilizing iron reserves (reduced from 1,220 +/- 73 to 739 +/- 111 mg, P < 0.0001). In the 24 non-overloaded patients (ferritin < 500 micrograms/l) the haemoglobin rose similarly from 7.04 +/- 0.18 to 10.70 +/- 0.36 g/dl (P < 0.0001), partly from iron reserves (depleted from 200 +/- 74 to -44 +/- 77 mg, P = 0.016) and partly from oral iron supplements (305 +/- 110 mg). In the overloaded patients the ferritin declined from 1057 micrograms/l (geometric mean, range 504-3699) to 317 micrograms/l (42-1505, P < 0.0001). In the non-overloaded patients it declined from 82 micrograms/l (8-461) to 45 micrograms/l (5-379, P = 0.016). The transferrin saturation (TS) in the overloaded patients appeared to decline from 38.3 +/- 7.2% to 24.0 +/- 3.7% but this was not statistically significant. In the non-overloaded the TS was unchanged (23.3 +/- 2.4 before and 28.1 +/- 3.6% after treatment). Considering all 38 patients together, the haemoglobin correlated negatively with the ferritin (r = 0.3731, P < 0.001) but not with the TS. The TS correlated with the serum ferritin initially (r = 0.75, P < 0.001) but not after the first 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Monitoring of iron requirements in renal patients on erythropoietin. 797 Jan 8

We have investigated the regulation of key human iron binding proteins in mononuclear phagocytes by IFN gamma and iron transferrin. In a previous study, we demonstrated that IFN gamma downregulates the expression on human monocytes of transferrin receptors, the major source of iron for the cell. In the present study, we show that IFN gamma also downregulates the intracellular concentration of ferritin, the major iron storage protein in the cell. By radioimmunoassay, the mean ferritin content of nonactivated monocytes was 361 +/- 107 fg/monocyte (mean +/- SEM) whereas the mean ferritin content of IFN gamma-activated monocytes was 64 +/- 13 fg/monocyte, an 82% reduction with activation (P < 0.01, t test). Consistent with its downregulating effect on these iron proteins, IFN gamma treatment also results in decreased iron incorporation. IFN gamma-activated monocytes incorporated 33% less iron from 59Fe-transferrin than nonactivated monocytes (P < 0.05, t test). Gel filtration chromatography revealed that incorporated iron is located primarily in ferritin in both nonactivated and IFN gamma-activated monocytes. Ferritin in IFN gamma-activated monocytes is saturated with approximately three times as much 59Fe as ferritin in nonactivated monocytes. We have also explored the effect of iron transferrin on transferrin receptor expression and intracellular ferritin content in human monocytes. We have found that iron transferrin markedly upregulates both transferrin receptor expression and intracellular ferritin content in both nonactivated (2.3- and 1.3-fold, respectively) and IFN gamma-activated (3.4- and 2.9-fold, respectively) monocytes. This study demonstrates that transferrin receptor expression and intracellular ferritin content in human monocytes is unidirectionally and coordinately upregulated by iron transferrin and unidirectionally and coordinately downregulated by IFN gamma.
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PMID:Regulation of transferrin receptor expression and ferritin content in human mononuclear phagocytes. Coordinate upregulation by iron transferrin and downregulation by interferon gamma. 845 71

Haemodialysis patients with iron overload sometimes develop resistance to erythropoietin therapy due to 'functional iron deficiency'. It is known that this resistance may be overcome by iron supplementation; however, the latter could worsen haemosiderosis. Therefore, we treated four iron-overloaded haemodialysis patients who had developed relative resistance to erythropoietin (among whom three had features of 'functional iron deficiency') with ascorbic acid (500 mg intravenously after haemodialysis, 1-3 times a week). The erythropoietin doses were voluntarily kept unchanged during the study. After a latency of 2-4 weeks, haematocrit and haemoglobin had increased respectively from 26.5 +/- 0.7 to 32.7 +/- 0.4 vol% and from 8.8 +/- 0.3 to 10.8 +/- 0.2 g/dl (means +/- SEM, P < 0.001). While serum ferritin remained unchanged, transferrin saturation increased from 27 +/- 7 to 54 +/- 12% (P < 0.05), suggesting that ascorbic acid supplementation had allowed mobilization of iron from tissue burdens. In one patient, haematocrit declined after withdrawal of vitamin C and increased again after rechallenge. Also, ascorbate supplementation was continued after the study in two patients and allowed the erythropoietin doses to be decreased, 8 and 11 weeks, respectively, after the start of the trial. When a control group of seven patients with normal iron status and without resistance to erythropoietin were challenged in the same manner with ascorbate, no elevation of haematocrit or transferrin saturation was noted. We conclude that ascorbate supplementation may circumvent resistance to erythropoietin that sometimes occurs in iron-overloaded patients, in particular, in the setting of 'functional iron deficiency'.
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PMID:Resistance to erythropoietin in iron-overloaded haemodialysis patients can be overcome by ascorbic acid administration. 852 94

The uptake of 59Fe ascorbate by suspensions of human enterocytes prepared from endoscopically derived duodenal biopsies was studied, with each subject's serum ferritin concentration determined at the time of endoscopy. Iron uptake was greatest at 37 degrees C. Uptake increased from pH 5.5 to 7.3, before being totally inhibited at pH 9.0. However, ferrous ion concentration, determined by 3-(2-Pyridyl)-5,6-bis(4-phenyl sulfonic acid)-1,2,4-triazine, was greatest at pH 5.5 and fell over this pH range. The rate of uptake was significantly greater by enterocytes isolated from individuals with a low serum ferritin (< 22 ng/L) compared with those with normal serum ferritin (> 22 ng/L). Vmax +/- (SEM) was 78.7 +/- 8.5 pmol Fe/(micrograms DNA.min) in the normal group (n = 12) and 141 +/- 17.2 pmol Fe/(micrograms DNA.min) in the low ferritin group (n = 4, P < 0.008). Corresponding Km values were 52.5 +/- 11.7 and 66.7 +/- 5.1 mumol/L, respectively (P < 0.91). Zinc, lead, cobalt and manganese added to the incubation buffer significantly lowered iron uptake into cells (unselected patients). The concentrations of each metal required to halve the uptake rate from 50 mumol/L iron (IC50) were 85 +/- 5 mumol/L (Zn), 570 +/- 170 mumol/L (Pb), 1.1 +/- 0.1 mmol/L (Co), and 3.8 +/- 0.7 mmol/L (Mn). The results demonstrate that enterocytes isolated by this method show the characteristics of iron uptake seen in animal studies. We suggest that these cells will be useful in the study of iron uptake in humans.
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PMID:Iron uptake by isolated human enterocyte suspensions in vitro is dependent on body iron stores and inhibited by other metal cations. 904 May 63

Erythropoietin (Epo) is a glycoprotein hormone produced in the kidney in response to hypoxia or anaemia. In acute renal failure (ARF) anaemia also occurs and current opinion is that Epo production is depressed with inappropriately low plasma levels throughout the uraemic phase. Our study was designed to determine the excretion of Epo in patients with ARF. Fifty-nine ventilated patients were studied, 39 with ARF and continuous veno-venous haemofiltration therapy (group 1) and 13 patients with normal renal function who served as a control group (group 2). All patients with ARF were anaemic and needed a mean transfusion of 0.6 units/day. Values for vitamin B12, folic acid, serum iron and ferritin were normal. While patients with normal renal function had Epo values within the normal range, patients with ARF had significantly higher values at the onset of haemofiltration therapy. Mean Epo (mean +/- SEM) values on days 0-2 were 92.6 +/- 11.7 mU/ml in group 1 and 16.5 +/- 6.4 mU/ml in group 2 (p < 0.0002). Epo levels declined in group 1 to 49 +/- 10.5 mU/ml on days 9 and 10 compared to 23 +/- 9.1 mU/ml in group 2 (ns). These values were maintained until the end of the observation period. No differences were seen between oliguric and non-oliguric patients. Our data show that patients with ARF have increased Epo levels at the beginning of the disease with a strong tendency to decrease, suggesting that there might be inadequate Epo levels during the course of acute renal failure.
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PMID:Erythropoietin in patients with acute renal failure and continuous veno-venous haemofiltration. 924 56

Total body water (TBW) is reduced in adult GH deficiency (GHD) largely due to a reduction of extracellular water. It is unknown whether total blood volume (TBV) contributes to the reduced extracellular water in GHD. GH and insulin-like growth factor I (IGF-I) have been demonstrated to stimulate erythropoiesis in vitro, in animal models, and in growing children. Whether GH has a regulatory effect on red cell mass (RCM) in adults is not known. We analyzed body composition by bioelectrical impedance and used standard radionuclide dilution methods to measure RCM and plasma volume (PV) along with measuring full blood count, ferritin, vitamin B12, red cell folate, IGF-I, IGF-binding protein-3, and erythropoietin in 13 adult patients with GHD as part of a 3-month, double blind, placebo-controlled trial of GH (0.036 U/kg.day). TBW and lean body mass significantly increased by 2.5 +/- 0.53 kg (mean +/- SEM; P < 0.004) and 3.4 +/- 0.73 kg (P < 0.004), respectively, and fat mass significantly decreased by 2.4 +/- 0.32 kg (P < 0.001) in the GH-treated group. The baseline RCM of all patients with GHD was lower than the predicted normal values (1635 +/- 108 vs. 1850 +/- 104 mL; P < 0.002). GH significantly increased RCM, PV, and TBV by 183 +/- 43 (P < 0.006), 350 +/- 117 (P < 0.03), and 515 +/- 109 (P < 0.004) mL, respectively. The red cell count increased by 0.36 +/- 0.116 x 10(12)/L (P < 0.03) with a decrease in ferritin levels by 39.1 +/- 4.84 micrograms/L (P < 0.001) after GH treatment. Serum IGF-I and IGF-binding protein-3 concentrations increased by 3.0 +/- 0.43 (P < 0.001) and 1.3 +/- 0.15 (P < 0.001) SD, respectively, but the erythropoietin concentration was unchanged after GH treatment. No significant changes in body composition or blood volume were recorded in the placebo group. Significant positive correlations could be established between changes in TBW and TBV, lean body mass and TBV (r = 0.78; P < 0.04 and r = 0.77; P < 0.04, respectively), and a significant negative correlation existed between changes in fat mass and changes in TBV in the GH-treated group (r = -0.95; P < 0.02). We conclude that 1) erythropoiesis is impaired in GHD; 2) GH stimulates erythropoiesis in adult GHD; and 3) GH increases PV and TBV, which may contribute to the increased exercise performance seen in these patients.
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PMID:The importance of growth hormone in the regulation of erythropoiesis, red cell mass, and plasma volume in adults with growth hormone deficiency. 928 31

The aim of the present prospective longitudinal study was to investigate the hormonal response in overtrained athletes at rest and during exercise consisting of a short-term exhaustive endurance test on a cycle ergometer at an intensity 10% above the individual anaerobic threshold. Over a period of 19+/-1 months, 17 male endurance athletes (cyclists and triathletes; age 23.4+/-1.6 yr; VO2max. 61.2+/-1.8 mL x min(-1) x kg(-1); means+/-SEM) were examined five times on two separate days under standardized conditions. Short-term overtraining states (OT, N=15) were primarily induced by an increase of frequency of high-intensive bouts of exercise or competitions without increase of the total amount of training. OT was compared with normal training states intraindividually (NS, N=62). During OT, the time to exhaustion of the exercise test was significantly decreased by 27% on average. At rest and during exercise, the concentrations in plasma and the nocturnal excretion in urine of free epinephrine and norepinephrine were not significantly changed during OT. At physical rest, the concentrations of (free) testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, and insulin during OT were comparable with those during NS. A significantly (P < 0.025) lower maximal exercise-induced increase of the adrenocorticotropic hormone and growth hormone, as well as a trend for a decrease of cortisol (P=0.060) and insulin (P=0.036), was measured. The response of free catecholamines as well as the ergometric performance of an all-out 30-s test was unchanged. Serum urea, uric acid, ferritin, and activity of creatine kinase showed no differences between conditions. In conclusion, the results confirm the hypothesis of a hypothalamo-pituitary dysregulation during OT expressed by an impaired response of pituitary hormones to exhaustive short-endurance exercise.
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PMID:Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes. 952 87

The short-term effect of calcium supplements (1200 mg Ca/d) on daily nonheme-iron absorption was measured in 14 healthy adult volunteers by using stable isotope extrinsic labeling and fecal monitoring techniques. Mean (+/- SEM) nonheme-iron absorption from a low-calcium (< 320 mg/d), moderately high-iron (15 mg/d) diet was 15.8 +/- 2.1%, but in the presence of calcium (400 mg/meal) as calcium carbonate, absorption fell significantly to 4.7 +/- 1.4% (P < 0.001). The long-term effect of consuming calcium supplements with meals (1200 mg Ca/d) on body iron (functional and storage iron) was investigated in 11 iron-replete adults over a 6-mo period. An unsupplemented control group (n = 13) was also monitored to correct for any seasonal changes in the biochemical measurements. There were no changes in any of the hematologic indexes, including hemoglobin, hematocrit, zinc protoporphyrin, and plasma ferritin resulting from the calcium supplementation. The results clearly show that long-term supplementation with calcium did not reduce plasma ferritin concentrations in iron-replete adults consuming a Western-style diet containing moderate to high amounts of calcium in most meals.
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PMID:Effect of calcium supplementation on daily nonheme-iron absorption and long-term iron status. 966 89


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