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)

We have investigated the importance of several clinical and laboratory parameters on the development of acquired cystic kidney disease (ACKD) as detected by ultrasonography in 19 patients who had received dialysis therapy for at least three years. We were particularly interested on the possible effect of the serum levels of oxalate and silicon, which can produce tubular obstruction, and that of vanadium, which can affect cell proliferation. The severity of ACKD increased with the duration of dialysis and was greater in men than in women. Positive correlations were observed between the grades of ACKD and the levels of hemoglobin, hematocrit, and parathyroid hormone, while there was a negative correlation between ACKD and serum ferritin levels. The serum levels of oxalate, silicon, and vanadium, pre- and postdialysis, were markedly and significantly higher than those in normal controls, but there was no significant correlation between these levels and the duration of dialysis therapy or severity of ACKD. The pre- and postdialysis levels of vanadium were not significantly different, while the levels of oxalate and silicon were significantly lower in the postdialysis samples. No significant correlations were detected between ACKD and age of the patients, blood pressure, protein catabolic rate, efficiency of dialysis index, or the serum levels of iron, sodium, potassium, calcium, phosphorus, aluminum, and beta 2-microglobulin.
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PMID:Oxalate, silicon and vanadium in acquired cystic kidney disease. 201 15

The reductive release of ferritin iron by several naturally occurring o-diphenols was studied. The initial rate of iron release was quantified by spectrophotometric measurement of the Fe(ferrozine)3(2+) complex, which absorbs maximally at 562 nm. The initial rate of iron release was dependent upon o-diphenol concentration, but not on the concentration of the chromophoric chelating agent, ferrozine, Stoichiometric measurements resulted in a ratio of 2Fe(II) released per molecule of o-diphenol. The series of o-diphenols studied included, caffeic acid, chlorogenic acid, dihydrocaffeic acid, 3,4-dihydroxybenzoic acid, and several analogs. These reductants represent an oxidation reduction potential range of 0.38 volts. A direct correlation between reducing power of the o-diphenols and rate of ferritin iron release was observed. Superoxide dismutase, catalase, mannitol, or general radical traps had no effect on the rate of iron removal; however, EDTA and oxalate inhibited iron release. A mechanism for ferritin iron reduction and release by o-diphenols consistent with the experimental observations is discussed.
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PMID:Reduction and release of ferritin iron by plant phenolics. 313 80

Cell-specific variations in apoferritin structure correlate with variations in iron metabolism that suggest functional specificity of the protein shell. Using EPR spectroscopy, we previously showed that vanadyl binds to specific sites on apoferritin, and that VO2+ binding is reduced by Fe(II) and Fe(III) (the natural substrates) and by metals known to influence iron storage (Chasteen, N. D., and Theil, E. C. (1982) J. Biol. Chem. 257, 7672-7677). Such observations suggest that the metal-binding site is important to apoferritin function and may define a location where the influence of cell-specific structural features are exerted. To investigate the iron-protein complex further, we have used x-ray absorption spectroscopy and have characterized, for the first time to our knowledge, Fe(III) apparently attached to the protein, after analyzing the x-ray absorption spectrum of an Fe(III)-apoferritin complex (10 Fe/molecule) compared to that of ferritin (polynuclear Fe(III)OOH, about 2000/molecule). The environment of iron in the Fe(III)-protein complex was similar to that in an Fe(III)-oxalate (2:3) hexahydrate complex, both in near edge structure and extended x-ray absorption structure, confirming earlier predictions of carboxylates as protein ligands. The extended x-ray absorption fine structure data for both compounds was fit best by a model in which a second shell of low Z atoms (carbon) was close (0.53-0.55 A) to the first shell of coordinated oxygen. However, small differences between Fe(III)-apoferritin and Fe(III)-oxalate in the Fe-O environment suggest a distorted geometry in the Fe(III)-protein complex and/or the presence of a mixture of atoms, such as nitrogen and oxygen, coordinated to iron. Extension of this approach to other apoferritins and metals will be likely to clarify the role of cell-specific features of the apoprotein in the formation of the iron core.
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PMID:A distinct environment for iron (III) in the complex with horse spleen apoferritin observed by x-ray absorption spectroscopy. 664 67

The release of iron from horse spleen ferritin by the chelating agents desferrioxamine B, rhodotorulic acid, 2,3-dihydroxybenzoate, 2,2'-bipyridyl and pyridine-2-aldehyde-2-pyridyl hydrazone (Paphy) has been studied in vitro. Ferritin prepared by classical procedures involving thermal denaturation releases its iron less effectively than ferritin isolated by a modified procedure that avoids this step. Desferrioxamine B and rhodotorulic acid are the most effective in releasing iron from both preparations of ferritin. When FMN is added, iron release by desferrioxamine B, rhodotorulic acid, and 2,3-dihydroxybenzoate was effectively blocked, whereas both bipyridyl and Paphy showed a marked simulation. A substantial increase in iron release was also observed for bipyridyl and Paphy with ascorbate; a less important increase was noted for rhodotorulic acid. EDTA exerted a marked inhibition of iron release from ferritin with rhodotorulic acid, 2,3-dihydroxybenzoate, bipyridyl, and Paphy. The effects of citrate and oxalate on iron release by the chelators was small. The effect of the concentration of flavin on iron release from ferritin by bipyridyl and desferrioxamine B have been studied. Desferrioxamine is unable to mobilize FeII from ferritin following reduction by reduced FMN, whereas bipyridyl can rapidly complex the ferrous iron. The results are discussed in the context of our current concepts of storage iron mobilization in the treatment of iron overload.
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PMID:Iron mobilization from ferritin by chelating agents. 719 39

To obtain more information on the effects of long-lasting endurance and strength training on the constituents of the blood, several haematological and iron-related parameters were measured at rest in 39 male athletes from the Polish team who participated in the Olympics in Seoul in 1988. The athletes were divided into two groups: endurance-trained subjects (group E, cyclists, canoeists and rowers; n = 22) and strength-trained subjects (group S, wrestlers and judo; n = 17). The control group was composed of untrained male subjects (n = 48). Blood samples were taken from an antecubital vein with the subject at rest for determinations of haemoglobin concentration ([Hb]), packed cell volume (PCV), erythrocyte (RBC) and reticulocyte count, plasma free haemoglobin concentration, haptoglobin concentration, serum iron, transferrin concentration and ferritin concentrations ([Ferr]); red blood cells were used for estimation of glutamato-oxalate transaminase (GOT) activity and free erythrocyte protoporphyrin concentration ([FEP]). The mean [Hb], PVC, RBC measured in the E athletes were significantly lower than in the control group but were comparable to those obtained in the S atheletes. There were no significantly differences in the haematological indices [mean corpuscular volume (MCV), mean copuscular haemoglobin and mean corpuscular haemoglobin concentration] between the groups of atheletes and the control group. A significant increase in reticulocytosis and GOT activity was observed in the endurance-trained athletes. No impairment of erythropoiesis was observed as indicated by several sensitive markers of haemoglobin formation (FEP, MCV and inspection of blood smears) in the athletes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Haematological and iron-related parameters of male endurance and strength trained athletes. 837 68

Adhesion of microcrystals to the apical surface of renal tubular cells could be a critical step in the formation of kidney stones. The role of membrane surface charge as a determinant of the interaction between renal epithelial cells (BSC-1 line) and the most common crystal in kidney stones, calcium oxalate monohydrate (COM), was studied in a tissue culture model system. Adhesion of COM crystals to cells was blocked by cationized ferritin. Other cations that bind to cells including cetylpyridinium chloride and polylysine, as well as cationic dyes such as Alcian blue, also inhibited adhesion of COM crystals, but not all polycations shared this effect. Specific lectins including Triticum vulgaris (wheat germ agglutinin) blocked crystal binding to the cells. Furthermore, treatment of cells with neuraminidase inhibited binding of crystals. Therefore, anionic cell surface sialic acid residues appear to function as COM crystal receptors that can be blocked by specific cations or lectins. In vivo, alterations in the structure, function, quantity, or availability of these anionic cell surface molecules could lead to crystal retention and formation of renal calculi.
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PMID:Adhesion of calcium oxalate monohydrate crystals to anionic sites on the surface of renal epithelial cells. 876 39

I.v. ascorbic acid has been used in an effort to mobilize ferritin stores in hyporesponsive HD patients receiving Epoetin alfa. However, not all patients who respond to i.v. ascorbic acid therapy will have subsequent decline in feritin stores (Gastaldello et al., 1995; Tarng & Huang, 1998). Additionally, predicting those patients who will overcome their Epoetin alfa hyporesponsiveness remains unclear. Ascorbic acid's effect on hemosiderin deposits may be another possible mechanism to the increased Epoetin alfa response observed in some HD patients (Hemosiderin is a pathologic deposition of iron in tissues including the spleen, small intestine, and bone marrow). Although there are no well-controlled studies evaluating hemosiderin and i.v. ascorbic acid, it should be noted that subjects with scurvy often present with excessive iron deposits in the tissues, indicating the possible effects of ascorbic acid on hemosiderin metabolism (Bothwell et al., 1964). Ascorbic acid deficiency is often present in many HD patients due to its removal during dialysis and lack of dietary intake (Ponka & Kuhlback, 1983). It remains controversial whether oral ascorbic acid supplementation is indicated in patients receiving HD. Therefore, the Recommended Daily Allowance (RDA) of 60 mg/day should be advised (Makoff, 1999). I.v. ascorbic acid should be considered as a possible adjuvant to therapy in patients who are "iron-overloaded" and hyporesponsive to Epoetin alfa. Although the long-term effects of i.v. ascorbic acid on HD patients is unknown, the potential risk of secondary oxalosis should be considered (Costello, 1991; Pru, Eaton, & Kjellstrand, 1985). It may be necessary to monitor plasma oxalate levels if long-term therapy with i.v. ascorbic acid is used. Clinical studies have examined i.v. ascorbic acid doses from 300 mg-500 mg given up to TIW for a maximum duration of 12 weeks without any significant deleterious effects (Gastaldello et al., 1995; Tarng & Huang, 1998; Tarng et al., 1999). However, large-scale, prospective, and controlled trails are needed to determine the long-term safety and efficacy of i.v. ascorbic acid therapy in iron overloaded HD patients receiving Epoetin alfa.
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PMID:Ascorbic acid use in hyporesponders to Epoetin alfa. 1127 34