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

Prevention of iron deficiency in low-birth-weight infants requires iron supplementation before neonatal iron stores are exhausted. In order to accurately determine when this depletion occurs, we measured the hemoglobin, mean corpuscular volume, serum iron/iron-binding capacity, and serum ferritin in 117 low-birth-weight infants (1,000 to 2,000 gm) from 0.5 until 6 months of age. All infants received banked breast milk in the hospital and breast milk or cow milk formula later; those with odd birth dates received 2 mg iron as ferrous sulfate/kg/day starting at 0.5 months; those with even birth dates received no additional iron unless they developed anemia. The results indicate that low-birth-weight infants who receive no supplemental iron may develop iron deficiency by three months of age and that a dose of iron of 2 mg/kg/day started at two weeks of age prevents iron deficiency without providing excess.
 ...
PMID:At what age does iron supplementation become necessary in low-birth-weight infants? 92 14

Concanavalin A (Con A) is taken up by endocytosis in mature erythrocytes of newborn humans but not in adult red cells. Thin sections of neonatal cells incubated with ferritin-conjugated Con A at 37 degrees show ferritin clusters on invaginations at the surface and in intracellular vesicles, but such invaginations and vesicles are absent with adult cells. The endocytosis induced by ferritin-conjugated Con A is inhibited at 0 degrees, and by methyl-alpha-D-mannopyranoside at 37 degrees. Succinylation of Con A, which is known to convert it from the tetrameric to dimeric form, renders Con A inactive in cell agglutination and endocytotic vesicle formation, presumably by reducing the number of oligosaccharide chains simultaneously bound by a single Con A molecule. Ferritin-conjugated succinyl Con A binds to neonatal erythrocytes but does not induce endocytosis; if, however, antibodies to ferritin are now added, endocytosis occurs. These results are consistent with a greater lateral mobility of at least a fraction of Con A recptors in the membrane of the intact neonatal erythrocyte compared to the adult. The results also support the hypothesis that the clustering of receptors is obligatory for endocytosis to occur. No discernible difference was found in the sodium dodecyl sulfate/polyacrylamide gel patterns of the membrane proteins of the neonatal and adult cells.
 ...
PMID:Clustering and endocytosis of membrane receptors can be induced in mature erythrocytes of neonatal but not adult humans. 106 94

In the present state of our knowledge it must be concluded that the outstanding anatomic changes directly attributable to acute iron poisoning are in the gastrointestinal tract and the liver. Both seem to be due to the direct action of iron upon living cells. In the stomach and small bowel the changes appear to be due to the corrosive effect of the iron salt whether in solution or in tablet form. And the anion may indeed play the predominant role as demonstrated by the observation of the severe corrosive changes observed when accumulations of ferrous sulfate tablets occur in areas of the stomach or small bowel. That the mucosal barrier to iron is broken down seems incontrovertible. And it is no longer tenable to assume that the severe complications of iron poisoning are due to the local necroses in the gastrointestinal tract. The liver, being the first parenchymal organ encountered by absorbed iron, is involved to a varying degree. The anatomic changes can progress to frank necrosis in severe cases. And even in those where overt histologic damage is not demonstrable, alterations in biochemical function occur. Anatomic changes in other parenchymal organs are probably largely secondary to dehydration, shock, hemorrhage, and infection. But the possibility of disordered enzyme systems here as well must be borne in mind though so far not demonstrated. In severe cases where hemorrhages play so large a role, albeit infrequently, the specific action of iron in interference with coagulation mechanisms is of the utmost importance. The role of therapy with deferoxamine in production of shock is discussed below. In this connection breakdown of the mucosal barrier with release of apoferritin and ferritin as a hypotensive mechanism has also been suggested by Smith.
 ...
PMID:Iron poisoning in children. 122 66

We evaluated three methods for isolating ferritin for use as a standard, with respect to purity of the products, ease of preparation, and yield. Examination of the respective products by gel filitration on Sephadex G-200 and Sepharose 6B suggested that the preparations isolated by ammonium sulfate and cadmium sulfate precipitation (Method 1) and by ultracentrifugation (Method 2) were homogeneous, while the product of a procedure including precipitation with ammonium sulfate (Method 3) contained significant amounts of nonferritin protein. The ratios of ferritin as measured by immunoradiometric assay to the amount of protein in the product indicated the ferritin prepared by Method 1 to be the most highly purified. Methods 1 and 2 were both comparatively simple. Although the yield from Method 1 was lowest, it is probably the method of choice, on the basis of the ease of obtaining a highly purified product. The most appropriate method for estimating protein in the isolated preparations appears to be that of Lowry et al.
 ...
PMID:Comparison of three procedures for isolating human ferritin, for use as a standard in an immunoradiometric assay. 125 34

Cell surface hydrophobicity of Mycoplasma hyopneumoniae was evaluated by phase partitioning in a hydrocarbon-aqueous mixture, by hydrophobic interaction chromatography, and by salting out with ammonium sulfate. Results obtained by use of these techniques gave evidence that the cell surface of M hyopneumoniae is weakly hydrophobic, compared with strongly hydrophobic Staphylococcus aureus Cowan I and hydrophilic Klebsiella pneumoniae. After treatment of the organisms with trypsin, M hyopneumoniae became less hydrophobic as measured by hydrophobic interaction chromatography. Significant changes in hydrophobicity were not seen after periodate treatment. Electron microscopy of M hyopneumoniae treated with polycationic ferritin revealed an intermediate, compact, unlabeled layer between the cytoplasmic membrane and an external, heavily labeled layer. Electron microscopy of ferritin-labeled M hyopneumoniae after treatment with trypsin or periodate revealed the intermediate layer to be composed of a trypsin-sensitive protein(s). The outer layer was made of periodate-sensitive carbohydrate(s). Therefore, it appears that proteins in the intermediate layer confer at least part of the total hydrophobicity of the mycoplasmal cell and may contribute to adherence of M hyopneumoniae to target respiratory cells by hydrophobic interactions.
 ...
PMID:Morphologic features and hydrophobicity of the cell surface of Mycoplasma hyopneumoniae. 132 25

Iron supplementation is usually required in patients receiving epoetin alfa. Ferrous sulfate is commonly prescribed, however many patients experience adverse gastrointestinal effects. Adverse effects may limit the amount of iron that can be prescribed, and may lead to noncompliance. Polysaccharide-iron complex (PIC) is an iron supplement containing greater amounts of elemental iron, and may produce fewer adverse effects. This study compared the efficacy and adverse effects of PIC to a historical period of treatment with ferrous iron salts to 38 dialysis patients receiving epoetin alfa. All patients were switched to PIC, and were followed for six months. The following laboratory information was recorded: hematocrit, serum iron concentration, percent transferrin saturation, total iron-binding capacity, serum ferritin concentration. Patients were given an adverse experience questionnaire at four and six months of PIC treatment. No differences in laboratory values were noted between treatments. The amount of prescribed elemental iron increased, while iron dextran use decreased during PIC therapy. Epoetin alfa doses were unchanged. Patients reported fewer gastrointestinal adverse effects at four months, however differences at six months were less striking. PIC is as effective as ferrous sulfate in sustaining erythropoiesis in patients receiving epoetin alfa. It may produce fewer adverse effects.
 ...
PMID:A prospective open-label study evaluating the efficacy and adverse reactions of the use of Niferex-150 in ESRD patients receiving EPOGEN. 136 44

To examine the influence of erythropoiesis on iron absorption, radioiron absorption tests were performed in normal subjects before and after a course of recombinant erythropoietin. The absorption of heme and nonheme iron from a standard meal was measured in nine subjects, and the absorption of a therapeutic dose of ferrous sulfate given with or without food was determined in an additional 11 subjects. The subcutaneous administration of 100 U recombinant human erythropoietin/kg body weight given on 10 successive days over a 2-week period induced a brisk increase in erythropoiesis and a sharp decrease in iron stores. With the standard meal, there was a modest increase in heme iron absorption from 47.0% to 58.6% (p < 0.05) and a dramatic five-fold rise in nonheme iron absorption from 5.9% to 31.8% (p < 0.001). The absorption of 50 mg iron as ferrous sulfate increased from 2.0% to 17.9% when given with food (p < 0.001) and from 7.0% to 24.6% when given with water (p < 0.001). To assess the effect of erythropoiesis independently of the induced changes in iron status, the absorption data were adjusted to a common serum ferritin level. The relative increase in iron absorption was still significant for both dietary nonheme iron (ratio 2.51, p < 0.02) and ferrous sulfate given with food (ratio 2.99, p < 0.01). It is concluded that the striking enhancement of iron absorption following regular erythropoietin administration in normal subjects is related to the combined effect of diminished iron stores and augmented erythropoiesis.
 ...
PMID:Effect of enhanced erythropoiesis on iron absorption. 143 4

This study compared the effect of loading apoferritin either with ferrous ammonium sulfate in various buffers or with ceruloplasmin and chelated ferrous iron. It was shown that loading of apoferritin with ferrous ammonium sulfate was dependent on buffer and pH, and was directly related to the rate of iron autoxidation. The ceruloplasmin-dependent loading of apoferritin, however, was unaffected by these factors. Isoelectric focusing and amino acid analysis of the differently loaded ferritins showed that ferrous ammonium sulfate loading of apoferritin resulted in the depletion of the basic amino acids, lysine and histidine, probably as a result of protein oxidation. No significant differences in amino acid composition was noted for ceruloplasmin-loaded ferritin. Furthermore, ferritin loaded with ferrous ammonium sulfate released more iron than either native or ceruloplasmin-loaded ferritin when either paraquat or EDTA was used as an iron mobilizing agent. We suggest that the loading of apoferritin with ferrous ammonium sulfate occurred as a result of iron autoxidation and may result in oxidation of amino acids and loss of integrity of the protein, and that ceruloplasmin may act as a catalyst for the incorporation of iron into apoferritin in a manner more closely related to that occurring in vivo.
 ...
PMID:In vitro loading of apoferritin. 153 76

Sodium chloride stimulated catalysis of oxidation of phosphatidylcholine liposomes by the soluble fraction of mackerel muscle. Chloride was determined to be the active component of the salt in this system. Sulfate also stimulated lipid oxidation. No difference was observed with either anion among sodium, potassium, or lithium cations. Redox iron was involved in the chloride stimulation of lipid oxidation by the press juice. Part of the chloride stimulation of the press juice was mediated through the high molecular weight (greater than 5 kdalton) fraction. Chloride improved the pro-oxidative effect of ascorbate on rat liver ferritin in vitro. It did not appear that production of chlorine radical by peroxidase was involved in the stimulatory effect of chloride.
 ...
PMID:Effect of NaCl on catalysis of lipid oxidation by the soluble fraction of fish muscle. 153 69

Transfer factor activities have been studied in both clinical and basic science settings for several decades. Until now, highly purified transfer factors that are suitable for molecular analysis have not been available. This has impeded progress towards understanding the molecular and cellular basis of the activities of these important inducers of cell-mediated immune responses. Murine transfer factors with specificities for chicken egg albumin or horse spleen ferritin were purified to virtual homogeneity using a combination of affinity chromatography and reversed-phase and polytypic high performance liquid chromatography (hplc). Transfer factors prepared by this methodology were recovered in high yield and in biologically-active, antigen-specific forms. The purified materials were further analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis, chromatographic methods and an in vivo assay for immunological activity. For the first time definitions for unit transfer factor activity and specific activity are introduced. The results of these experiments indicate that transfer factors are a family of highly polar, hydrophilic molecules of low molecular weight (approximately 5,000) which are produced in small quantities by lymphoid cells and which have potent biological activity. The availability of purified transfer factors should facilitate definitive studies into the nature and mechanisms of production and action of these molecules.
 ...
PMID:Purification of transfer factors. 154 96


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>