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)

Nutritional assessments are frequently based on amounts of nutrients consumed. In the present paper the usefulness of nutrient intake data for assessing nutrient adequacy is examined in an elderly British population. Subjects were "free-living' elderly aged 68-90 years (sixty men, eighty-five women) in Norwich. Forty-two of forty-nine surviving males and sixty-seven of seventy-nine surviving females were reassessed after 2 years. With few exceptions, estimated micronutrient intake was not statistically predictive of biochemical measures of nutrient adequacy. Initial biochemical measures of nutritional adequacy were compared with those found 2 years later in an attempt to assess whether initial biochemical assessment was predictive of the "longer term' situation. Biochemical measurements at the start of the study were correlated to the same measurements made 2 years later for: serum ferritin, haemoglobin and erythrocyte count, whole-blood Se-glutathione peroxidase (EC 1.11.1.9; males only), plasma Cu, alkaline phosphatase (EC 3.1.3.1), ascorbic acid, vitamin B6 (pyridoxal-5-phosphate), folate and vitamin B12, total erythrocyte thiamin (males only), riboflavin (erythrocyte glutathione reductase (EC 1.6.4.1) activation coefficient): but not for: erythrocyte Cu-superoxide dismutase (EC 1.15.1.1) or plasma Zn. Either only small changes, or no changes, in mean values were seen over the 2 years for most of the biochemical measures. One exception was a large increase in plasma folate. The only important "negative' features seen at 2-year follow up were a large fall in serum ferritin concentration and a large increase in the activity of two antioxidant defence enzymes, superoxide dismutase and glutathione peroxidase. As judged by currently accepted biochemical deficiency threshold values, a small proportion of subjects were possibly at risk of Fe (3% men; 1% women), folate (7%, 3%), thiamin (12%; 3%) and vitamin C (15%; 17%) deficiency. Many more appeared to be at risk of vitamin B6 (42%; 47%) and riboflavin (77%; 79%) deficiency. It was concluded that the requirements of the elderly for vitamins B1, B2 and C, and the biochemical deficiency threshold values used to indicate vitamin B6 deficiency, need review.
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PMID:Relationships between micronutrient intake and biochemical indicators of nutrient adequacy in a "free-living' elderly UK population. 913 69

The rates of initiation of free radicals were determined in systems containing horse spleen ferritin, H2O2, tert-butyl hydroperoxide (TBHP) or cumene hydroperoxide (CHP) in acetate buffer (pH 4.2) or phosphate buffer (pH 6.0) with 10-15% dimethylformamide (DMF). Benzidine (BD), benzidine sulfate (BDS), o-tolidine (TL), 3,3',5,5'-tetramethylbenzidine (TMB), and o-phenylenediamine (PDA) were used as acceptors. In the systems ferritin-H2O2 oxidation of amine acceptor follows Michaelis-Menten kinetics. For all aromatic amines kcat, Km, and their ratios were determined. Peroxidase efficiency of ferritin in the TMB oxidation by hydrogen peroxide (kcat/km) is characterized by a value 2.82.10(3) M-1.sec-1 comparable with ferroxidase efficiency of apoferritin in the oxidation of Fe2+ by oxygen. Reactivity of aromatic amines in the system ferritin-H2O2 is similar to the reactivity registered in their peroxides oxidation and is maximal for TMB and PDA. Bimolecular rate constants of TMB and PDA oxidation in the reaction with H2O2, TBHP, and CHP were compared in acetate buffer (pH 4.2 using 0.5 microM ferritin and 5 mM concentration of each substrate. On the oxidation of both amines activity of oxidants decreased in the following order: H2O2 > TBHP > CHP. A scheme of radical initiation in the systems ferritin-ROOH (H2O2)-amines and the influence of radical acceptors apoferritin and organic co-solvent on the rate of reactions are discussed.
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PMID:Initiation of radicals in biochemical systems: ferritin-hydroperoxides-aromatic amines. 927 78

Vascular calcification (VC), which is described in the elderly and in diabetics, is frequently seen in uraemia. It is usually regarded as having little significance. We studied the roentgenological appearance of VC in a homogeneous group of 38 long-hours haemodialysis patients whose longevity on dialysis allowed sustained (10-25 years) follow-up, including annual skeletal surveys and thrice-yearly clinical examinations and biochemical profiles. We compiled a dossier of clinical and laboratory parameters from the start of dialysis to the present day. We were able to analyze the natural history of VC and to determine which clinical parameters were linked with progression. We found that VC became steadily more prevalent-at dialysis onset present in 39% of the patients, but in 92% after an average dialysis duration of 16 years, with a mean onset 9.7 years after starting dialysis. As well as becoming more prevalent, the calcification became progressively more severe in most patients. There were two patterns of VC: axial (aorta and iliac and femoral arteries), seen alone in 32% of the patients, and peripheral (digital arteries), seen alone in 3% of patients. Most patients (65%) had evidence of both types. Calcification was scored for site and severity. Patient age (r = 0.57, p < 0.001), systolic blood pressure (r = 0.54, p < 0.001), hyperparathyroidism (reduced progression after parathyroidectomy), plasma phosphate (r = 0.34, p = 0.042), and vitamin D concentrations (r = 0.53, p < 0.001) were the principal determinants of severity and rate of progression of VC in this population. There was a weak negative association between progression and serum ferritin (r = -0.33, p = 0.046). The reduced vessel compliance that results from VC is likely to be cardiovascularly deleterious. In severe cases, tissue perfusion or vascular access for haemodialysis can be compromised. VC and accelerated cardiovascular mortality are common to uraemia, diabetes, and systolic hypertension in the elderly. Better understanding of these pathological processes may permit intervention and possibly lead to a reduction in cardiovascular mortality.
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PMID:Vascular calcification in long-term haemodialysis patients in a single unit: a retrospective analysis. 938 Feb 36

The L chain of the iron storage protein ferritin contains more putative nucleation sites in the core (Glu53, 56, 57, 60, and 63) than does the H chain (Glu61, 64, and 67). Recombinant DNA techniques were used to investigate the role of these putative nucleation sites on iron loading by ceruloplasmin and on the stability of the iron core. Recombinant rat liver ferritin H chain homopolymer and the two mutants (E61A and E61A-E64A), containing three, two and one nucleation sites, respectively, loaded up to 2010 +/- 50, 2010 +/- 40, and 1950 +/- 40 atoms of iron per ferritin, respectively. However, the mutations resulted in a 50% decrease in the rate of iron loading by ceruloplasmin. The ferritin variants incorporated the same amount of phosphate after iron loading (410 +/- 20, 400 +/- 30, and 420 +/- 20 atoms per ferritin, respectively). The stability of the iron cores prior to phosphate incorporation, assessed by the rate of iron release by 10 mM EDTA and the paraquat cation radical, corresponded to numbers of proposed nucleation sites. The subsequent incorporation of phosphate seemed to stabilize the iron core and minimized the effect of numbers of putative nucleation sites in ferritin on the rate of iron release by EDTA and the paraquat cation radical. After incorporation of phosphate the ferritins behaved similarly to the native rat liver ferritin with respect to the rate of iron release by the paraquat cation radical.
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PMID:The effect of putative nucleation sites on the loading and stability of iron in ferritin. 947

The thermal inactivation of horse spleen ferritin was studied over a range of temperatures (36-52 degrees C) in 0.1 M acetate buffer (pH 4.2) as a decrease of its peroxidase activity during tetramethylbenzidine (TMB) oxidation by hydrogen peroxide. The activation energy of this process was 163.3 kJ/mole. Thermodynamic activation parameters for the loss of peroxidase activity of ferritin were calculated. The influence of various detergents on ferritin-dependent oxidation of TMB, ortho-tolidine, and ortho-phenylenediamine (PDA) by hydrogen peroxide was studied in 0.1 M phosphate buffer (pH 6.0) at 20 degrees C. Relatively high concentrations of charged detergents (SDS and cetyltrimethylammonium bromide) decreased the peroxidase activity of ferritin with all three amines, whereas moderate concentrations of the nonionic detergent Triton X-100 did not influence oxidation of these substrates. Increase of dimethylformamide concentration in 0.02 M acetate buffer (pH 4.2) from 5 to 40% strongly decreased the rate of TMB and PDA oxidation by hydrogen peroxide or cumene hydroperoxide. Decrease in the activity of thermally inactivated ferritin with TMB as substrate, reduction of alpha-helical content of the protein at 40-50 degrees C, an inactivating effect of charged surfactants and organic co-solvent on the peroxidase activity of ferritin indicate a very important role of the apoprotein in peroxidase function. A possible mechanism of apoferritin participation in peroxidase catalysis is discussed.
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PMID:Role of the apoprotein in the catalytic peroxidase-like function of ferritin. 948 74

Embryonic dysmorphogenesis has been blocked by antioxidant treatment in vivo and in vitro, suggesting that embryonic excess of reactive oxygen species (ROS) has a role in the teratogenic process of diabetic pregnancy. We report that the basal levels of ROS in dispersed rat embryonic cells in vitro, as determined by fluorescence of dichlorofluorescein (DCF), were not different in cells from control and diabetic pregnancy at day 10 or 12. Beta-hydroxybutyrate (beta-HB) and succinic acid monomethyl ester both augmented DCF fluorescence in cells from day 12 embryos of normal and diabetic rats but not from day 10 embryos. Cells of day 10 and day 12 embryos from normal and diabetic rats responded to increasing glucose concentrations with a dosage-dependent alleviation of DCF fluorescence. Day 10 embryonic cells exhibited high glucose utilization rates and high pentose phosphate shunt rates, but low mitochondrial oxidation rates. Moreover, in vitro culture of embryos between gestational days 9 and 10 in the presence of 20% oxygen induced an increased and glucose-sensitive oxidation of glucose compared with embryos not cultured in vitro. At gestation day 12, however, pentose phosphate shunt rates showed a decrease, whereas the mitochondrial beta-HB oxidation rates were increased compared with those at gestation day 10. This was paralleled by a lower expression of glucose 6-phosphate dehydrogenase- and phosphofructokinase-mRNA levels at day 12 than at day 10. On the other hand, H-ferritin mRNA expression at day 12 was high compared with day 10. None of the mRNA species investigated were affected by the diabetic state of the mother. It was concluded that beta-HB-induced stimulation of mitochondrial oxidative events may lead to the generation of ROS at gestational day 12, but probably not at day 10, when only a minute amount of mitochondrial activity occurs. Thus our results do not support the notion of diabetes-induced mitochondrial oxidative stress before the development of a placental supply of oxygen.
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PMID:Beta-hydroxybutyrate increases reactive oxygen species in late but not in early postimplantation embryonic cells in vitro. 951 22

Determining the possible association of viral hepatitis infection and degree of pruritus is the primary concern of this study. Ninety-six adequately dialyzed CAPD patients (47 male and 49 female) and 526 normal controls (266 male and 260 female) were enrolled. Blood hemoglobin, ferritin, electrolytes, calcium, phosphate, albumin, urea, creatinine, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase, and bilirubin were analyzed by routine methods. Serum HBsAg was examined, using a radioimmunoassay method and the anti-HCV, an enzyme immunoassay method. All cases were interviewed with a standardized questionnaire. The highest possible pruritus score (PS) was 22. The prevalences of HBsAg(+) and anti-HCV(+) were 14.6% and 17.7%, respectively. The mean PS in all 96 CAPD patients was 11.6 (range 7-22). The mean PS were 11.8 +/- 0.6 and 12.5 +/- 1.0 for patients infected with HBV and HCV, respectively. Both were significantly higher than that (10 +/- 0.9) of patients without hepatitis infection. AST and ALT were significantly higher in patients infected with viral hepatitis than those without. The other biochemical parameters were not significant. Thirty-seven (38.5%) of our 96 patients had mild pruritus (PS < or = 7) and 11 (15.9%) had severe pruritus (PS > or = 15). Of the 83.9% (26/31) patients with viral hepatitis, the grades of skin itching were moderate to severe; whereas those of the patients without viral hepatitis, 53.6% (37/69) belonged to the group of moderate to severe pruritus (p = 0.003, chi 2 test with Yates' correction). The authors recommended screening of viral hepatitis infection to be undertaken for uremic patients with unexplained skin itching.
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PMID:Viral hepatitis infection should be considered for evaluating uremic pruritus in continuous ambulatory peritoneal dialysis patients. 968 Nov 57

To elucidate the mechanism by which red blood cells (RBC) participate in thrombus formation, we investigated the mechanism of adhesion between human RBC. Our study showed that the morphology of RBC was changed by various cationic reagents, inducing adhesion between RBC. When RBC suspended in PBS buffer containing sodium phosphate (PBS(Na)) or potassium phosphate (PBS(K)) were treated with cationic reagents, stronger adhesion occurred between RBC treated with the latter. When concentrations of the reagents were low, adhesion was released and the RBC resumed its original morphology after washing. However, when the concentrations of reagents were high, the morphology did not normalize, although the adhesion was released. When fresh RBC were treated with cationized ferritin (CF), CF bound to the periphery of RBC membranes and induced adhesion. However, when RBC were induced to adhere strongly by a cationic reagent, no binding of CF to the membrane was not observed. When RBC were treated with CF, bindings between substances outside the membranes and bindings between the membranes and substances outside the membranes were observed. When RBC treated with neuraminidase to remove 85-90% of sialic acid were treated with the cationic reagents, both adhesion between RBC and morphological change were reduced. When RBC were pretreated with polyclonal antibody against human RBC membrane band 3 protein, treatment with the cationic reagents did not induce adhesion and morphological change of RBC. Further, when RBC induced to adhere by the cationic reagents were treated with the polyclonal antibody against band 3, in the case of weak adhesion, the adhesion was released and the RBC resumed its original morphology. However, in the case of strong adhesion, the morphology did not return to normal although the adhesion was released. These results suggest that the adhesion between RBC induced by cationic reagents was due to changes in the charge on the membrane surface, involving polysaccharide chains and membrane surface proteins.
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PMID:Adhesion of human red blood cells and surface charge of the membrane. 970 3

Abnormal oxidative processes including a reduction in thiamine-dependent enzymes accompany many neurodegenerative diseases. Thiamine deficiency (TD) models the cellular and molecular mechanisms by which chronic oxidative aberrations associated with thiamine-dependent enzyme deficits cause selective neurodegeneration. The mechanisms underlying selective cell death in TD are unknown. In rodent TD, the earliest region-specific pathological change is breakdown of the blood-brain barrier (BBB). The current studies tested whether nitric oxide and microglia are important in the initial events that couple BBB breakdown to selective neuronal loss. Enhanced expression of endothelial nitric oxide synthase and nicotinamide adenine dinucleotide phosphate diaphorase reactivity in microvessels, as well as the presence of numerous inducible nitric oxide synthase-immunoreactive microglia, accompanied the increases in BBB permeability. Nitric oxide synthase induction appears critical to TD pathology, because immunoreactivity for nitrotyrosine, a specific nitration product of peroxynitrite, also increased in axons of susceptible regions. In addition, TD elevated iron and the antioxidant protein ferritin in microvessels and in activated microglia, suggesting that these cells are responding to an oxidative challenge. All of these changes occurred in selectively vulnerable regions, preceding neuronal death. These findings are consistent with the hypothesis that the free radical-mediated BBB alterations permit entry of iron and extraneuronal proteins that set in motion a cascade of inflammatory responses culminating in selective neuronal loss. Thus, the TD model should help elucidate the relationship between oxidative deficits, BBB abnormalities, the inflammatory response, ferritin and iron elevation, and selective neurodegeneration.
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PMID:Induction of nitric oxide synthase and microglial responses precede selective cell death induced by chronic impairment of oxidative metabolism. 970 19

The aim of this study was to find out the relationship between body iron stores and serum aluminum levels among 82 stable CAPD patients. The influence of other factors such as time on CAPD and residual renal function was also considered. Thirty-three patients received aluminum hydroxide as a phosphate binder, and they had significantly higher aluminum levels (36.45 microg/l) than the patients who were not taking aluminum preparations (17.2 microg/l, p = 0.001). A statistically-significant correlation between serum aluminum levels and residual renal function and time on CAPD was also observed (p <0.05). However, there was no relationship between serum aluminum levels and serum iron, ferritin and transferrin saturation, neither between body iron stores and total excretion of aluminum (p >0.05). In previous reports, low serum iron levels were associated with high serum aluminum concentration among hemodialysis patients. However, this effect was not observed in the CAPD population under study. The highest risk of hyperaluminemia was found in the patients who were taking aluminum hydroxide, had worse residual renal function and had been longer on CAPD.
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PMID:Factors influencing serum aluminum in CAPD patients. 972 77


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