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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatic iron uptake and metabolism were studied by subcellular fractionation of rat liver homogenates after injection of rats with a purified preparation of either native or denatured rat transferrin labelled with 125I and 59Fe. (1) With native transferrin, hepatic 125I content was maximal 5 min after injection and then fell. Hepatic 59Fe content reached maximum by 16 h after injection and remained constant for 14 days. Neither label appeared in the mitochondrial or lysosomal fractions. 59Fe appeared first in the supernatant and, with time, was detectable as ferritin in fractions sedimented with increasingly lower g forces. (2) With denatured transferrin, hepatic content of both 125I and 59Fe reached maximum by 30 min. Both appeared initially in the lysosomal fraction. With time, they passed into the supernatant and 59Fe became incorporated into ferritin. The study suggests that hepatic iron uptake from native transferrin does not involve endocytosis. However, endocytosis of denatured transferrin does occur. After the uptake process, iron is gradually incorporated into ferritin molecules, which subsequently polymerize; there is no incorporation into other structures over 14 days.
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PMID:The mechanism of hepatic iron uptake from native and denatured transferrin and its subcellular metabolism in the liver cell. 49 1

A micro method has been developed for the separation of the principal classes of iron proteins in needle biopsy specimens of human liver. The iron content of the fractions was determined by automated flameless atomic absorption spectrophotometry in a one step procedure. The levels of total iron, transferrin-, ferritin-, haemprotein- and haemosiderin-iron are reported for control tissue.
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PMID:Separation and assay of iron proteins in needle biopsy specimens of human liver. 49 29

Serum iron, total iron-binding capacity, and percentage saturation of transferrin have classically been used to demonstrate a hypoferremic state; however, these tests may not discriminate between depleted iron stores and conditions associated with defective reticuloendothelial release of iron. Estimation of stainable iron in the bone marrow biopsy specimen is then the most practical way to assess body iron stores. With the availability of a radioimmunoassay procedure for serum ferritin, we undertook a prospective study to determine whether serum ferritin concentrations might replace assessment of the marrow biopsy iron stores as an indicator of hypoferremia. Iron stores were absent from bone marrow biopsy specimens from 104 patients. A good correlation between low serum ferritin levels and absence of iron stores in biopsy specimens was found for 91 patients (87.5%). Thirteen (12.5%) had normal serum ferritin concentrations with absence of biopsy iron. These individuals had hematopoietic malignancies or active hepatic disease, or were receiving iron therapy. In this group, a bone marrow biopsy would still be necessary for evaluation of a hypoferremic state, even though the serum ferritin concentration might be normal.
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PMID:Serum ferritin and bone marrow iron stores. I. Correlation with absence of iron in biopsy specimens. 50 95

Three prototype tridentate ligands (i.e., pyrazinecarboxaldehyde thiosemicarbazone, sodium pyrazinecarboxaldehyde dithiocarbazonate, and pyrazinecarboxaldehyde 2'-pyrazinylhydrazone) were prepared and evaluated for their relative abilities to remove iron from model systems designed to mimic particular aspects of chronic transfusional iron overload. These compounds were synthesized by condensation of pyrazinecarboxaldehyde with the appropriate substituted hydrazide. Iron-binding properties were determined, and the ability to remove iron from the proteins transferrin and ferritin was ascertained. An in vivo model system employing iron-loaded mice was used to demonstrate that all three compounds were effective at reducing tissue iron levels.
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PMID:Synthesis and evaluation of the thiosemicarbazone, dithiocarbazonate, and 2'-pyrazinylhydrazone of pyrazinecarboxaldehyde as agents for the treatment of iron overload. 53 78

Syncytiotrophoblast microvillous plasma membrane (StMPM) preparations were obtained from human full-term placentae by previously published methods of cold saline extraction and phase centrifugation. Purity of these preparations was assessed by electron microscopy, enzyme analysis and hydroxyproline content. IgG, albumin, alkaline phosphatase, transferrin, ferritin and alpha 2-macroglobulin were consistently detected in the aqueous soluble fraction from sodium deoxycholate-solubilised StMPM preparations by antigenic or electrophoretic analysis, beta 2-Microglobulin was not detected in these preparations. Up to 21 discrete protein bands could be demonstrated by SDS--PAGE, and their molecular weights determined. Many of these components need to be further identified, including a glycoprotein of molecular weight 36 500 which was particularly prominent. The soluble fraction from StMPM preparations gave a single strong precipitin reaction in immunodiffusion against wheat germ agglutinin, but not against other lectins studied.
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PMID:Characterisation of the soluble fraction of human syncytiotrophoblast microvillous plasma membrane-associated proteins. 55 Nov 70

Hematological values were measured in 28 newborn infants of mothers smoking 10-20 cigarettes daily during pregnancy, and in 25 infants of non-smokers. Higher hematocrit levels were found on the 1st day of life in infants of smoking mothers (60.8 +/- 5.0%, mean +/- S.D.) compared to controls (57.5 +/- 4.8%) (p less than 0.05). The hematocrit levels correlated positively with the maternal smoking level (r = 0.318, p less than 0.05) and the maternal serum thiocyanate concentrations at delivery (r = 0.389, p less than 0.01). Cord serum values for erythropoietin, serum-iron, transferrin and ferritin showed no statistically significant difference between the two groups. A significant inverse correlation was found between the hematocrit value on the 1st day of life and the cord serum ferritin concentration (r = -0.495, p less than 0.005). The present results suggest that maternal smoking stimulates fetal erythropoiesis, probably through a hypoxic effect on the fetus, dose related to the maternal smoking level. Increased erythropoiesis may cause increased iron incorporation into erythrocytes at expense of iron storage in the bone marrow and reticuloendothelial system.
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PMID:Smoking during pregnancy--hematological observations in the newborn. 57 17

Breast feeding is thought to result in a lower incidence of iron deficiency than does the use of unfortified cow milk forumalas, but there is scant documentation for this belief. The relationship of breast and cow milk feeding to absorption of iron and to iron status was investigated in a total of 45 term infants at about six months of age. Iron absorption was measured by total body counting. Laboratory assessment of iron status was based on the serum ferritin, hemoglobin, mean corpuscular volume, and transferrin saturation. The results indicated that infants fed breast milk during the entire first six to seven months of life attained greater iron stores than did those fed a cow milk formula. Breast-fed infants absorbed an average of 49% of a trace dose of extrinsic iron administered during a breast feeding in contrast to about 10% reported to be absorbed from cow milk under similar conditions. The data indicate that term infants who are breast fed may not require routine administration of supplemental iron.
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PMID:Iron absorption in infants: high bioavailability of breast milk iron as indicated by the extrinsic tag method of iron absorption and by the concentration of serum ferritin. 57 4

Thirty healthy infants, aged 11-13 months, were studied with regard to the iron absorption from proprietary milk formula. The infants were divided into three groups (I-III) depending on the concentration of iron in the formula: 0.8 (I), 6.8 (II), and 12.8 (III) mg/l, respectively. The calculated amount of iron absorbed per test dose of 50 ml of milk averaged 5 microgram (I), 32 microgram (II), and 43 microgram (III). Group I differed significantly from groups II and III. No correlation was found between iron absorption and hemoglobin, MCV, serum transferrin saturation or serum ferritin within the range of normal values. Our findings suggest that at least 7 mg of iron as ferrous sulphate per litre of formula is required to prevent iron deficiency.
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PMID:Iron absorption from infant milk formula and the optimal level of iron supplementation. 57 48

1. A standardized decompensation and recompensation of iron homeostasis has been produced by a change-over from normal to iron deficiency and back. 2. Under these conditions the 59Fe uptake into transferrin and ferritin of the mucosal "cytosol" and SDS treated "membrane" fraction has been measured together with the 59Fe amount transferred into the body. 3. The increase of the intestinal 59Fe absorption due to a progressive iron deficiency is associated with an increase of the 59Fe uptake into the mucosal transferrin of the "cytosol" and the "membrane" fraction; the reverse is observed with regard to mucosal ferritin. 4. Three days after the re-establishment of normal conditions the 59Fe absorption was lowered to normal values, while the 59Fe uptake into mucosal ferritin achieved again normally high values. 5. The high apparent rate of absorption in iron deficient animals decreased during the last 50 min after injection of the 59Fe labelled test dose. The 59Fe content in the ferritin fraction increased simultaneously, whereas the 59Fe content in the transferrin fraction remained the same. 6. The conclusion is drawn that the intestinal iron absorption is regulated by both mucosal iron binding proteins. Mucosal transferrin is responsible for the increase of absorption in iron deficiency while mucosal ferritin is responsible for the inhibition of iron absorption when the iron homeostasis recompensats.
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PMID:Mucosal transferrin and ferritin factors in the regulation of iron absorption. 59 98

The iron status of two groups of pregnant women was investigated. One group did not receive iron (group B), the other erceived 100 mg iron/day (group A). 1. In all individuals concentrations of hemoglobin, serum iron, transferrin and serum ferritin were determined at regular intervals from the third month until delivery and at 3 months after delivery. The same determinations were performed in cord blood. 2. Changes in iron status appeared to be less in individuals with iron supplement than in those without iron supplement. A fall in Hb, serum iron and serum ferritin is observed in all individuals. 3. Three months after delivery the Hb concentration has generally returned to the normal female value, but the serum ferritin concentration is still very low. 4. The fetus does not discriminate as to the iron status of the mother. In both groups (A and B) cord blood values appeard to be not significantly different.
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PMID:Serum ferritin and iron stores during pregnancy. 62 Apr 71


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