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)

Heme proteins such as myoglobin or hemoglobin, when released into the extracellular space, can instigate tissue toxicity. Myoglobin is directly implicated in the pathogenesis of renal failure in rhabdomyolysis. In the glycerol model of this syndrome, we demonstrate that the kidney responds to such inordinate amounts of heme proteins by inducing the heme-degradative enzyme, heme oxygenase, as well as increasing the synthesis of ferritin, the major cellular repository for iron. Prior recruitment of this response with a single preinfusion of hemoglobin prevents kidney failure and drastically reduces mortality (from 100% to 14%). Conversely, ablating this response with a competitive inhibitor of heme oxygenase exacerbates kidney dysfunction. We provide the first in vivo evidence that induction of heme oxygenase coupled to ferritin synthesis is a rapid, protective antioxidant response. Our findings suggest a therapeutic strategy for populations at a high risk for rhabdomyolysis.
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PMID:Induction of heme oxygenase is a rapid, protective response in rhabdomyolysis in the rat. 163 13

Fifteen guinea pigs were divided into three groups: the control, the ferritin and the glycerol-ferritin groups. In the first group, no any medication had been given; in the second group, ferritin 1 gm/kg was injected via the jugular vein; in the third group, 50% glycerol 3 ml/kg was injected 30, 60 and 120 minutes prior to the injection of ferritin. Striae were removed, fixed and embedded in Epon. Ultra-thin sections were cut and observed under electron microscope. No ferritin molecule was seen in the control group. In the ferritin group, the ferritin particles were seen in stria capillary only. In the glycerol-ferritin group, the ferritin molecules had entered the endothelial cells of stria capillary at 30 minutes. Ferritin molecules had got into stria vascularis and accumulated around the mitochondria at 60 minutes. The electron-opaque tracers had migrated to the apex of the marginal cells along microtubular system and permeated to the endolymphatic space through cell membranes and junctions. The ferritin particles appeared at the surface of marginal cells in the endolymphatic space at 120 minutes. The results indicate that glycerol can serve as an opener of blood-labyrinth barrier.
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PMID:[Glycerol opening of blood-labyrinth barrier using electron-opaque tracer ferritin]. 270 94

An optimized procedure for the preparation of fabric reinforced polyacrylamide gels for native protein blotting is described. The gels, typically 5% T, 3% C, were internally stabilized with the aid of an AcrylAide-pretreated, hydrophilized polyester fabric, preferably with a 60 microns mesh opening. Ultrathin (120-180 microns) gels were prepared with the flap technique and 500 microns gels with the cassette technique; 500 microns gels with immobilized pH gradients were cast using precision molds and a computer controlled mixing device of four burettes. The fabric reinforced gels could be used either wet or after drying and rehydration. Isoelectric focusing was performed in carrier ampholyte pH gradients or hybrid immobilized pH gradients, supplemented with 1-3% w/v carrier ampholytes. Incorporation of 40-60% w/v glycerol into the gels decisively improved their operational properties. The high glycerol gels, which tolerated field strengths of 900-1700 V/cm for extended periods under steady state focusing conditions, were not afflicted by liquid exudation on the gel surface and showed retarded diffusion of the separated proteins on termination of focusing. By unidirectional capillary blotting, with an intermediate dialysis membrane eliminating bidirectional protein transfer, proteins were blotted to 0.1-0.2 micron pore size nitrocellulose membranes in 10-20 min from ultrathin gels and in 30-60 min from 500 microns gels. Based on quantification of residual protein in the gels after blotting, a transfer efficiency of 60-87% was found for the ultrathin and 53-69% for the 500 microns gels. Semidry electrophoretic blotting was carried out in a modified setup with cooled graphite electrodes. In a continuous Tris-glycine buffer system electrophoretic blotting required only 2-5 min with ultrathin gels and 20 min with 500 microns gels. Marker proteins, including horse spleen ferritin (Mr465,000), could be transferred with 91-96% efficiency.
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PMID:Native protein blotting after isoelectric focusing in fabric reinforced polyacrylamide gels in carrier ampholyte generated or immobilized pH gradients. 324 47

Studies were designed to examine fluid-phase pinocytosis in proximal tubular cells. Canine proximal tubules were obtained from the band IV of Percoll gradient centrifugation of the dispersed renal cortex, and were seeded on collagen-coated polycarbonate membranes. Integrity of monolayers was confirmed by electrophysiologic measurements, and by scanning electron microscopy. At confluence cell monolayers were studied in Ussing chambers. The rate of transfer of a marker of fluid-phase pinocytosis, Lucifer Yellow CH, from the luminal to the basolateral bath was three times higher than that occurring in the opposite direction. Fluorescence microscopy demonstrated that Lucifer Yellow was trapped exclusively in the vesicular compartment. Electron microscopy of the monolayers incubated with cationized ferritin added to the luminal or to the basolateral both revealed that endocytic vesicles were formed only at the luminal surface. Luminal-to-basolateral transfer of Lucifer Yellow was almost completely blocked at 0 degrees C, and was significantly diminished by K+ depletion. Transcytosis of Lucifer Yellow was stimulated twofold by 1-oleoyl-2-acetyl-glycerol. Transfer of quin-2 acetoxymethylester across the monolayer was used as a marker of the paracellular pathway, demonstrating the lack of directional selectivity of this transport route. In summary, vectorial fluid-phase pinocytosis in proximal tubular cells represents an additional mechanism contributing to fluid transport in this segment of the nephron.
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PMID:Transcytosis in cultured proximal tubular cells. 382 Feb 80

1. Single muscle fibres from frog semitendinosus were subjected to sudden changes in [K](o), while recording membrane potential.2. In agreement with Hodgkin & Horowicz (1960), a sudden increase in [K](o) in normal fibres produced a rapid depolarization (half-time 0.3 sec), whereas a sudden decrease in [K](o) produced a slower repolarization (half-time 2-3 sec).3. Fibres were subjected to ;glycerol-treatment', a procedure which was supposed to produce a functional disconnexion of the T-system from the surface. In these glycerol-treated fibres both depolarization and repolarization induced by changes of [K](o) took place rapidly.4. The results suggest that the slowness of the repolarization in normal fibres is due to a retention of K ions inside the T-tubules.5. Electron microscopical observation of single fibres or bundles of fibres, which have been soaked in a Ringer containing ferritin, revealed that normal fibres contained ferritin particles in the T-system, while glycerol-treated fibres showed no ferritin. Except for the presence of some large vacuoles and some swelling of the T-system, glycerol-treated fibres appeared morphologically normal.6. Prolonged soaking in a high potassium solution produced electrical effects suggesting that K ions can enter the tubules of treated fibres very slowly, in spite of their inaccessibility to ferritin.7. The main effect of glycerol-treatment does not seem to be a total disconnexion of the T-system from the fibre surface, but rather constriction of the T-tubules near their openings to the exterior.
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PMID:Speed of repolarization and morphology of glygerol-treated frog muscle fibres. 454 76

Freeze etching of solute model systems (e.g., glycerol or ferritin solutions) demonstrates that cryofixation can introduce serious artifacts due to the segregation of the dissolved or dispersed material from the solvent. Since, in principle, this problem can be reduced by increasing the cooling rate, a new technique has been developed which combines spray freezing with freeze etching. This spray-freeze-etching is applied by first spraying the specimen into a liquid cryomedium. The frozen droplets are then "glued" together with butylbenzene to form a regular freeze-etch specimen, while the temperature of the sample is kept at -85 degrees C. The results obtained by spray-freeze-etching are far superior to those obtained by standard freezing. Our results, using 5% glycerol as a test specimen, are equivalent to those obtained by the high-pressure method (1). The reduction of segregation during freezing makes freeze etching a method applicable for the investigation of solute systems. Furthermore, the study of unicellular organisms or cellular fractions by freeze etching without the use of antifreeze is made possible.
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PMID:Improved cryofixation applicable to freeze etching. 494 87

Iron, copper, and zinc utilization were examined in nine adult males fed a moderate calcium-moderate phosphorus diet (MCaMP), a moderate calcium-high phosphorus diet (MCaHP), and a high calcium-high phosphorus diet (HCaHP) during a 39-day balance study. The moderate and high calcium diets contained 780 mg and 2382 mg calcium daily, respectively. The moderate and high phosphorus diets contained 843 and 2442 mg phosphorus daily, respectively. The calcium supplements were fed as calcium gluconate, while the phosphorus supplements were fed as glycerol phosphate. Subjects lost more iron and copper in their feces and apparently retained less iron and copper when fed the HCaHP diet than when fed the other two diets, but these effects were not statistically significant. Urinary iron and copper excretion were significantly affected by the dietary treatments. Dietary treatments had no effect on subjects' fecal and urinary losses of zinc nor on their apparent retention of zinc. Plasma iron, zinc, copper, and transferrin levels and serum ferritin levels were not affected by the dietary treatments.
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PMID:Effect of dietary calcium and phosphorus levels on the utilization of iron, copper, and zinc by adult males. 705 62

The effects of vegetarian fasting were evaluated in 14 grossly obese patients who participated in a program comprising 5 weeks' fasting in a lactovegetarian health center. Before and after the fasting period the patients were hospitalized and put on a standardized weight-maintaining diet; at the health center they consumed vegetable juices containing less than 1 MJ and 3 g of protein per day. The weight reduction (mean +/- S.D.) was 13.4 +/- 5.0 kg (from 132.0 +/- 27.2 to 118.6 +/- 16.1 kg). Except for the first few days the patients had no severe hunger sensations. No severe adverse clinical effects were noted. The laboratory status--comprising serum or plasma levels of minerals, protein, and lipids; hematological data; and variables reflecting liver and thyroid function--revealed abnormal group mean values only for ferritin and the acute-phase reactants haptoglobin, C-reactive protein, and anti-chymotrypsin in the obese. The levels of potassium, retinol-binding protein, and haptoglobin decreased, and aminotransferase and lactate dehydrogenase activities and free fatty acid and glycerol concentrations increased as a result of the fasting. The most striking effect of the weight reduction was an increase in the HDL cholesterol levels. Fasting according to the described regimen thus seems to provide a safe method for treatment of obese patients.
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PMID:Vegetarian fasting of obese patients: a clinical and biochemical evaluation. 713 69

Studies on plasmalemmal expansion in isolated nerve growth cones identified large, clear vesicles characteristically found in growth cones as the plasmalemmal precursor. The present article examines these plasmalemmal precursor vesicles (PPVs) in greater detail in the intact cell. (a) Pulse-chase experiments with the phospholipid precursor, [3H]glycerol, followed by radioautographic analysis show that PPVs in distal neurites and growth cones are labeled prior to equilibration of the label with the plasmalemma. (b) Pulse-chase experiments with lectin-ferritin conjugates demonstrate that PPVs are not endocytotic, that they contain lectin receptors, and that, during growth, patches of lectin receptors appear on the plasmalemma covering PPV clusters. (c) Freeze-fracture studies show that this plasmalemma shares with PPVs a paucity of intramembrane particles. (d) Lectin labeling experiments and freeze-fracture analysis demonstrate, furthermore, that the plasmalemma forms a network of invaginations at the base of PPV clusters. (e) Correlative studies indicate that the refractive 'vacuoles' seen in growth cones by phase-contrast light microscopy correspond to the PPV clusters seen at the ultrastructural level. These results confirm the identity of the plasmalemmal precursor in the intact cell and demonstrate that PPV clusters form distinct, dynamic organelles specialized for plasmalemmal expansion in the growth cone.
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PMID:Sites of plasmalemmal expansion in growth cones. 849 Oct 40

Cellular content of heme is regulated by heme oxygenase, the rate limiting enzyme in the degradation of heme. Induction of heme oxygenase is a protective response in an in vivo model of heme protein mediated renal injury, the glycerol model of acute renal failure. In addition to heme, heme oxygenase is induced by diverse forms of oxidative stress, the functional significance of which is currently unknown. We examined whether heme oxygenase is induced, and the functional significance of such induction, in two in vivo models of oxidant-induced toxic nephropathy, namely, cisplatin and gentamicin nephropathies; nephrotoxicity in these models is not dependent on the delivery of a burden of heme proteins to the kidney as occurs in the glycerol model. We demonstrate induction of heme oxygenase mRNA and protein in the kidney as early as 6 and 12 hours after a single dose of cisplatin (6 mg/kg i.v.). Pretreatment with tin protoporphyrin, a competitive inhibitor of heme oxygenase, led to higher serum creatinine values on days 3 through 5 and lower inulin clearances on day 5; tin protoporphyrin also exacerbated renal injury in this model. Renal hemodynamics studied at day 2 after cisplatin demonstrate reduced renal blood flow rates, increased renal vascular resistance and increased fractional excretion of sodium in rats treated with tin protoporphyrin. Tin protoporphyrin alone had no significant effect on serum creatinine and renal hemodynamics in rats with intact, disease-free kidneys. We confirmed that tin protoporphyrin prevented the increase in heme oxygenase activity induced by cisplatin. Induction of heme oxygenase by cisplatin was associated with increased kidney heme content and ferritin content.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Induction of heme oxygenase in toxic renal injury: a protective role in cisplatin nephrotoxicity in the rat. 856 92


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