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

Reliable methods for assessing the iron status of a population are essential for developing effective public health measures to combat iron deficiency. The hemoglobin concentration, transferrin saturation, free erythrocyte protoporphyrin, and serum ferritin are all useful but they vary widely in their specificity and sensitivity for detecting iron deficiency. In applying these laboratory parameters, the usual approach in nutritional surveys is to determine the percentage of values outside the normal range. As an alternative, a model is presented here that uses these measurements to estimate the distribution of iron stores in a population. This approach may be particularly useful for evaluating the effectiveness of iron supplementation and fortification programs.
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PMID:Assessing iron status of a population. 48 29

Rats were chronically iron-overloaded by intraperitonel injections of iron-dextran. Electron microscopy revealed that the excess iron was deposited in ferritin-like particles packed in lysosomes and scattered in hepatic cytoplasm. No mitochondrial iron deposition or damage was seen. Furthermore, mitochondrial preparations from chronically iron-overloaded animals were found to be contaminated with lysosomes, which could explain previously reported increases in mitochondrial iron by chemical analysis. Mitochondrial function, as measured by cytochromes a-a3, b and c concentrations as well as activity of the rate-limiting enzyme of haem synthesis, delta-aminolaevulinate synthetase, was not diminished by chronic iron-overloading. Microsomal haem was decreased by 30% at the time that haem oxygenase, the rate-limiting enzyme of haem degradation, was increased approx. 3-fold. Animals were given a single intraperitoneal injection of iron-dextran and the activities of delta-aminolaevulinate synthetase and haem oxygenase were measured over 24 h. delta-Aminolaevulinate synthetase activity increased approx. 2-fold in these acutely iron-overloaded rat livers, but at a time after the increase in haem oxygenase. These results suggest that an early consequence of excess iron in liver is acceleration of the rate of haem degradation, possible by haem oxygenase.
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PMID:Induction of liver cell haem oxygenase in iron-overloaded rats. 48 9

Utilizing the techniques of stereo-electron microscopy (stereo-EM) and energy-dispersive x-ray analysis (EDX), we have studied aspects of the ultrastructure of avian reticulocytes. Stereo-EM of thin sections (0.10 to 0.25 mum thick) stained with uranyl and lead revealed the three-dimensional arrangement of 25 nm chromatin fibers on the tangential surfaces of nuclei. Use of the Bernhard staining procedure in combination with stereo-EM permitted a three-dimensional view of the interchromatin spaces and channels leading to the nuclear pores, and of cytoplasmic polyribosomes. With either staining technique we frequently encountered in the cytoplasm clusters and paracrystalline arrays of electron-dense granules with granule diameters approximately 1/2 that of monomer ribosomes. These granules were highly electron-dense in unstained specimens and have been identified as intracellular ferritin on the basis of the similarity of their ultrastructural morphology to that of horse spleen ferritin and their high content of iron as determined by EDX. The possibility that these granules represent toxic products of phenylhydrazine treatment (Heinz bodies) is considered unlikely, since we have demonstrated in this study that Heinz bodies cannot be visualized in unstained preparations, do not reveal the same granular structure, and do not contain significant amounts of iron above background. The occurrence of intracellular ferritin is discussed in light of current concepts of iron transport and storage during erythropoiesis.
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PMID:Stereo-electron microscopy and energy-dispersive x-ray analysis of avian reticulocytes. 48 23

In order to study the effects of the protein moiety independent of the protein-iron complex in the development of ferritin-induced glomerulonephritis, we compared the effects of ferritin, equimolar amounts of apoferritin, and equimolar amounts of iron dextran in Swiss albino mice. The results were compared to both saline-injected and non-injected controls. Ferritin resulted in a glomerulonephritis associated with predominantly mesangial deposition of immune complexes. Tubulo-interstitial changes occurred as well. Iron dextran resulted in similar but less severe tubulo-interstitial changes and evoked no glomerular alterations. Apoferritin resulted in an immune complex glomerulonephritis usually associated with membranous deposits. No tubular or interstitial changes occurred. Proteinuria developed in animals receiving apoferritin. Since the protein-iron complex caused tubular and interstitial damage, apoferritin may provide a more suitable model of immune-complex-mediated glomerulonephritis.
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PMID:Ferritin- and apoferritin-induced immune complex glomerulonephritis in mice. 49 22

Ten groups of healthy infants and children from 2 months to 15 years of age were studied, each consisting of 98 to 238 subjects. In young infants whose serum ferritin values indicated ample storage iron, the concentration of hemoglobin was found to bear a significant relationship to the degree of iron saturation of transferrin. This phenomenon was evident throughout the range of transferrin saturation until 1 year of age but became undetectable or less significant from 2 to 15 years of age. We postulate that the production of hemoglobin could be influenced through a broader range of transferrin saturation in rapidly growing infants than in the older child or adult.
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PMID:Relationship between hemoglobin concentration and transferrin saturation in iron-sufficient infants. 49 47

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

Recently developed techniques for the investigation of iron kinetics were used to study the disturbance of iron metabolism in 19 untreated patients with Hodgkin's diseases (HD). The erythroid abnormality in newly diagnosed HD appears to be confined to those patients with systemic symptoms of weight loss, night sweats and fever, and consists of depression of marrow erythroid activity. These patients had a significnatly lower haemoglobin and serum iron concentration and a higher serum ferritin concentration, both when compared to normal subjects and to those patients with HD who lacked systemic symptoms. Ineffective erythropoiesis and red-cell destruction were not significantly increased. The present findings, confirm that HD patients with systemic symptoms have a depression of erythropoiesis, and that in these patients the marrow fails to respond to the stimulus of mild anaemia.
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PMID:Erythropoiesis and iron metabolism in Hodgkin's disease. 50 65

Serum ferritin, serum iron, total iron binding capacity, and haemoglobin levels were measured in a group of 36 pregnant women before, one week after, and four weeks after a total dose infusion of iron dextran (T.D.I.). The serum ferritin level is considered to provide a reliable index of maternal iron stores one month, but not one week, after TDI.
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PMID:Reliability of serum ferritin determinations after total dose infusion of iron dextran in pregnancy. 51 78


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