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)

Ferritin was isolated from the seeds of pea (Pisum sativum) and lentil (Lens esculenta). The homogeneity of the phytoferritins was established by polyacrylamide-gel electrophoresis. The subunit molecular weights were respectively 20 300 and 21 400 for hte pea and lentil proteins. A neutron low-angle scattering study established the molecular weight of the oligomer as 480 000 for pea apoferritin and 510 000 for lentil apoferritin. Although the quaternary structure of 24 polypeptide chains is preserved, the phytoferritins have a larger cavity in the interior than mammalian ferritins and can thus potentially store 1.2-1.4 times as much iron. The amino acid composition of the phytoferritins show some similarities to those of mammalian apoferritins; tryptic 'fingerprinting' reveals that there are many differences in the amino acid sequence of plant and mammalian apoferritins.
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PMID:Isolation and characterization of phytoferritin from pea (Pisum sativum) and Lentil (Lens esculenta). 65 49

Hyperbaric oxygen therapy (HBO) has been used in the treatment of cerebral edema with variable results. Two different actions of HBO, one decreasing and the other increasing cerebral edema, have been postulated. We examined the permeability of the blood-brain barrier (BBB) in rats and cats. Animals of each species were treated for 90 min/d with 100% oxygen at a pressure of 2.5 atm for 5 consecutive days. Following treatment, cadmium-free ferritin was injected intravenously. Sections of the brain were prepared for electron microscopic evaluation of the capillaries and their neighboring structures. Perivascular edematous zones were observed. Ferritin particles penetrated through the capillary endothelium and into the pericapillary structures. Hyperbaric oxygenation appears to increase the permeability of cerebral vessel walls in normal animals. Further work on this phenomenon may provide a more rational basis for the treatment of cerebral edema with HBO.
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PMID:Changes in the permeability of the blood-brain barrier under hyperbaric conditions. 66 82

The transfer of iron between horse spleen [55Fe]ferritin and human apotransferrin or [59Fe]transferrin in homogeneous solution was investigated. Transfer between the two proteins in the presence of citrate, ATP, or ascorbate occurs in both direction, but the net flow is always from ferritin to transferrin. Ferritin which is ca. 1/3 to 1/2 saturated with iron appears to be most reactive. Chemically prepared apoferritin does not accept iron from diferric transferrin. Citrate-mediated transfer of iron from ferritin to apotransferrin is first order with respect to ferritin, zero order with respect to transferrin, and has a complex dependence upon citrate concentration. Direct transfer of iron from native or reconstituted ferritin to apotransferrin in the absence of any identifiable mediating agent was observed to occur at about half the rate attained in the presence of 1 mM citrate. No transfer of iron between the two proteins occurs across a dialysis membrane in the absence of a mediating agent. No binding of transferrin and ferritin to each other was demonstrable. One possible explanation for these observations is that iron from the core of ferritin is in equilibrium with iron near the outer surface of the protein, where the metal would be available to transferrin.
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PMID:Iron exchange between ferritin and transferrin in vitro. 69 86

1. Human liver ferritin was separated by preparative isoelectric focusing into six fractions. 2. Except for the least acidic fraction the reactivity with antibody against spleen ferritin increased with rising pI, but with antibody against heart ferritin the reactivity decreased. 3. The highest iron content was found in the most acidic isoferritins and progressively decreased with rising pI. 4. Iron uptake was studied in apoferritin prepared from heart and liver ferritin fractions separated by ion-exchange chromatography. There was good correlation between the rate of iron uptake and pI. The most acidic fractions took up iron more rapidly than did the more basic ones. 5. Ferritin was prepared from heart, liver, spleen and kidney. There was little difference on isoelectric focusing between ferritin obtained from normal tissues and the corresponding iron-loaded tissues from patients who had received multiple blood transfusions. The iron-loaked heart ferritin invariably contained relatively more of the basic isoferritins. Normal and iron-overloaded heart ferritins were separated into isoferritin fractions by ion-exchange chromatography, and in each case there was a fall in iron content as the pI increased. The iron content of ferritin from the iron-overloaded heart was higher throughout than that from normal heart. 6. There is a relationship between the rate of iron uptake by apoferritin and pI, and this probably accounts for the variation in iron content of the isoferritins found in human liver and heart.
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PMID:Properties of human tissue isoferritins. 70 84

Ultrastructural changes in the arterioles of the intestinal submucosa were observed in rats 20 to 24 hr after bilateral nephrectomy. Sham-operated rats served as controls. The changes of arterial pressure after the nephrectomy or sham operation was measured directly through carotid artery cannulation, and analysed by the paired t-test. Ferritin was injected intravenously into two rats in each group 60 min. before fixation in order to trace plasma insudation into the arteriolar wall. Mean blood pressure was 102 +/- 9 and 112 +/- 6 mm Hg (mean +/- S.E.), before and after the nephrectomy, respectively. The latter was significantly higher than the former, though it remained in the normotensive range. It was also higher than that in control rats after sham operation. In sham-operated rats, there were neither vascular lesions nor evidence of increased leakage of ferritin into arteriolar walls. Arterioles from the nephrectomised rats, on the other hand, exhibited foci of smooth muscle cell necrosis characterised by cellular fragmentation and the deposition of fibrinoid and electron-dense granules. The fibrinoid was of two types of axial periodicity, i.e., 20--23 nm and 16--17 nm, respectively. Dense granules, 13--90 nm in diameter, were encountered mainly between the basement membrane and plasma membrane of smooth muscle cells. Though scanty fibroblasts were seen, there was no infiltration of mononuclear cells in the adventitia accompanying medial necrosis. Ferritin particles accumulated in the necrotic foci of the media in high concentration, and were seen in endothelial gaps, within the cytoplasm and in palsmalemmal vesicles of the endothelial cells. The main pathway of ferritin insudation into the media was considered to be by way of endothelial gaps.
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PMID:Early vascular changes in the intestine of bilaterally nephrectomised rats. 72 77

The ultrastructure of capillaries and their permeability to horseradish peroxidase and ferritin in rat posterior pituitary has been studied. The capillary wall is formed mainly by flat endothelium penetrated by regularly situated fenestras. The majority of organelles is concentrated in the perikaryon. Caveoles and pinocytotic vesicles are not numerous except for some perikaryons where they are concentrated along the basal surface. Intracellular clefts are interrupted in the regions of fusion of the outer osmiophilic layers of membranes of neighbouring endothelial cells. Horseradish peroxidase and ferritin penetrate partly from the capillary lumen into the pericapillary space: the majority of markers penetrate across the fenestras and the minority--within pinocytosis vesicles. The former way is more rapid than the latter. Ferritin penetrated into the cytoplasm is captured by lysosomes.
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PMID:[Capillary ultrastructure and permeability in the posterior lobe of the rat pituitary]. 72 59

Carcinoembryonic antigen (CEA) levels were determined in 114 patients with confirmed lung cancer at the time of diagnosis using the CEA Ire-Sorin radioimmunoassay. Elevated CEA values were found in 47%. Most of the patients with high CEA levels had clinically detectable metastases. Ferritin was detectable by the Laurell-electrophoresis in the serum of 58 out of 81 (72%) of the patients with confirmed lung cancer at the time of diagnosis. Ferritin levels were significantly higher in patients with metastases. Serial measurements of CEA and ferritin during radio- and chemotherapy showed that the assay may be useful to evaluate the effects of therapy. Because of some false negative results both CEA and ferritin determinations should be used only in context with other clinical and laboratory findings.
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PMID:Carcinoembryonic antigen and ferritin in patients with lung cancer before and during therapy. 72 75

The penetration of horseradish peroxidase and ferritin into the neurosecretory axones in the rat's posterior pituitary has been studied with the electron microscope. Markers were revealed in neurosecretory granules, in empty vesicles of the same size, in neurotubules, in lamellar bodies and in the axoplasm. Markers were taken up from the extracellular space by micropinocytotic "synaptic" vesicles and probably by larger empty vesicles. It is supposed that the contents of these vesicles penetrate into the granules to take part in their maturation. Besides, the contents of synaptic vesicles probably penetrate into neurotubules and are retrogradally transported to perikaryons of neusecretory cells. Ferritin is taken up from axoplasm by lamellar bodies that possess lysosomal activity.
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PMID:[Pathways of substance penetration into the neurosecretory axons in the posterior lobe of the rat hypophysis]. 73 67

Ferritin conjugates of a lectin from mistletoe (Viscum album L.) were used for the electron-microscopic demonstration of carbohydrate receptors on the cell surface of human erythrocytes and murine tumor cells. Human A1 erythrocytes showed only a slight focal binding of ferritin. Cells of the mouse ascites tumor strain L 1210 were labelled very tightly on their surface and incorporate the ferritin by pinocytosis. Furthermore they showed cytotoxic changes in their ultrastructure. In the presence of galactose the labelling on the surface, the incorporation of the conjugate within the cell as well as the cytotoxicity were inhibited.
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PMID:[Use of ferritin conjugates of a lectin from mistletoe (Viscum album L.) for the electron microscopic localization of cell surface receptors]. 75 6

A procedure for the separation of ferritin-antibody conjugates from free antibody has been developed using isokinetic sucrose density gradient sedimentation. The gradient (5% w/w sucrose at the top to about 35% at the tube bottom) provides optimal separation of 7S free immunoglobulin from the ferritin (65S) and ferritin-antibody conjugate. Recovery of the conjugate band is simple and avoids problems of aggregation found by centrifugal pelleting and resuspension procedures. The method was tested by labeling human globulin and fractionating the gradient. Free antibody was detected at the top one-fifth of the gradient by immunodiffusion. Ferritin and the labeled antibody were found one-third to one-half of the way down the gradient. Immunoelectrophoresis was also used to demonstrate the separation of unconjugated ferritinand ferritin labeled antibody from free antibody.
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PMID:Separation of ferritin labeled antibody from free antibody. 82 84


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