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)

Fluid shear force may deform point-attached erythrocytes to become droplike shaped and anchored by a single long or 2-4 short tethers. By addition of glutaraldehyde to the medium the cells were fixed such as to stabilize this deformation for ensuing SEM, freeze-fracture, fine structural, and ultrahistochemical studies. Freeze-fracture specimens revealed identical numbers and distribution patterns of membrane particles in both the membrane of tethers and of the droplike portions of red cells. Segregated vesicles most often were located adjacent to the attachment site of the tether. All of the vesicles were devoid of membrane particles. Irrespective of their length, the tethers were about 0.1 micrometer in diameter. Cross-sections of the tether membrane and the plasmalemma of the major part of the cell appeared identical. Ultrahistochemical studies revealed the same intensity of iron binding capacity and affinity to ferritin labelled anti AHP at either area of the deformed erythrocyte membrane. Segregating vesicles were also stained by colloidal iron and by fer-anti AHP. By means of the DAB-reaction no haemoglobin was demonstrated within the vesicles. All of these findings corroborate the notion, that lipid molecules were segregated from the membrane whose curvature increased considerably during the formation of the tether.
 ...
PMID:Lipid segregation from human erythrocyte tethers. 616 75

Thirty-six women with menorrhagia were treated with mefenamic acid during all menstrual periods for more than 1 year. These women had experienced objective and subjective benefit--menstrual blood loss was reduced and other menstrual symptoms improved during a preliminary 4-cycle double-blind placebo-controlled trial with mefenamic acid (placebo cycles: 65.6 +/- 5.3 ml; mefenamic acid cycles: 45.3 +/- 5.1 ml, mean +/- SEM). This reduction in menstrual blood loss was maintained at 6 to 9 months (49.2 +/- 9.9 ml) and at 12 to 15 months (42.8 +/- 4.8 ml) after the trial. These reductions were significant at the 6- to 9-month (paired t test = 2.18; P less than .05) and the 12- to 15-month interval (paired t test =- 4.40; P less than .001). Significant sustained reductions in blood loss were seen in the women with menorrhagia due to ovulatory dysfunctional bleeding and in those who had undergone tubal sterilization. Significant reductions were also seen in dysmenorrhea, headache, nausea, diarrhea, depression, number of sanitary towels used, and number of mefenamic acid capsules taken. A significant increase in serum ferritin was found between admission and completion of the follow-up trial in 11 women (P less than .01).
 ...
PMID:Long-term treatment of menorrhagia with mefenamic acid. 633 54

We used concanavalin A (con A)-peroxidase-iron dextran-diaminobenzidine (DAB) technique for the electron microscopic detection of con A binding sites on cell membranes. Normal bladder mucosa showed a sparse distribution of con A binding sites with both transmission (TEM) and scanning (SEM) electron microscopy, but bladder tumors showed a higher concentration in the distribution of con A binding sites in proportion to the histopathological grade of transitional cell carcinoma. Quantitative estimation of the con A binding sites was attempted using scanning X-ray pulse analysis of iron elements contained in the reaction complexes. Con A binding sites were quantitatively the smallest in normal mucosa, increasing proportionate to the grade of the bladder tumor. Some specimens were compared by the ferritin-labelled method and the pattern of ferritin conjugates distribution was similar to that seen with the con A-peroxidase-iron dextran method.
 ...
PMID:Distribution of concanavalin A binding sites on normal human urinary bladder mucosa and bladder tumors by transmission and scanning electron microscopy and X-ray microanalysis. 674 Aug 37

In long-term cultures of bone marrow, the adherent stromal cells provide support for the proliferation and maintenance of hemopoietic stem cells. These stromal cells and their interactions were characterized by means of scanning (SEM) and transmission (TEM) electron microscopy in correlation with functional studies. Cultures were initiated by establishing the adherent stromal layer as a "soil" which was then "seeded" after 3 weeks by the addition of another marrow-cell suspension. Clonal assay of the supernatant demonstrated the continuous proliferation of the hemopoietic stem cell. The stroma essentially consisted of two cell types, macrophages and epithelioid cells. Macrophages were smaller, 10-15 microns, phagocytosed latex and carbon particles, and contained lysosomes. Their surface did not stain with polycationic ferritin (PCF). Epithelioid cells were much larger, more than 100 microns; contained numerous thin, elongated mitochondria; did not phagocytose latex particles; but did display strong surface staining with PCF. The appearance of epithelioid cells in TEM depended on their state of development and whether the section was parallel or perpendicular to the substratum. Epithelioid cells displayed a maturational spectrum, at two ends of which were synthetic and storage phases. In the synthetic phase, the cell contained numerous profiles of rough endoplasmic reticulum, and in the storage phase, numerous storage granules. These two phases were best appreciated in sections perpendicular to the substratum, demonstrating synthetic cells on top settling over the substratum upon maturation into the storage cells. Both macrophages and epithelioid cells contained fat globules which increased in number and size with the addition of hydrocortisone to the culture medium. A distinct fat-cell type, as has been claimed, was not found in this study. Granulopoiesis was observed in the culture system in the absence of colony-stimulating activity in the supernatant, suggesting direct cellular interaction or short-range factors in the induction of granulopoiesis. Widespread cellular interactions were noted between macrophages and epithelioid cells, the latter often completely embracing the former and both extending cytoplasmic processes toward each other. This is reminiscent of the cooperative interaction of endoderm and mesoderm in chick embryo hemopoiesis and may be necessary for the maintenance of stem cells in these cultures.
 ...
PMID:Morphological studies on long-term culture of marrow cells: characterization of the adherent stromal cells and their interactions in maintaining the proliferation of hemopoietic stem cells. 710 79

Liver iron concentrations were determined in 60 alcoholics with liver disease of varying severity, 15 patients with untreated idiopathic hemochromatosis, and 16 control subjects with biliary tract disease. Mean liver iron concentrations (microgram/100 mg dry weight) were significantly greater in the alcoholics (156.4 +/- 7.8 (SEM); P less than 0.05) and in patients with idiopathic hemochromatosis (2094.5 +/- 230.7; P less than 0.01) than in control subjects (53.0 +/- 7.0). Liver iron concentrations of greater than 140 micrograms/100 were found in 17 alcoholics (29%) and in all 15 patients with idiopathic hemochromatosis. Liver iron concentrations greater than 1000 micrograms/100 mg were found in all patients with idiopathic hemochromatosis but in none of the alcoholics. In the alcoholics no relationship existed between liver iron concentrations and the amount of alcohol consumed daily, the length of the drinking history, the amount of beverage iron consumed daily, or the severity of the liver disease. Serum ferritin concentrations reflected iron stores in patients with hemochromatosis and in alcoholics with minimal liver disease. However, in alcoholics with significant liver disease serum ferritin concentrations did not reflect iron stores accurately, although with normal values iron overload is unlikely. Serum iron concentration and percentage saturation of total iron-binding capacity were of little value in assessing iron status in either alcoholics or patients with hemochromatosis. Measurement of the liver iron concentration clearly differentiates between alcoholics with significant siderosis and patients with idiopathic hemochromatosis.
 ...
PMID:Hepatic iron stores and markers of iron overload in alcoholics and patients with idiopathic hemochromatosis. 711 74

A technique has been developed for the localization of isotopes in the scanning electron microscope. Autoradiographic studies have been performed using a model system and a unicellular biflagellate alga. One requirement of this technique is that all manipulations be carried out on samples that are maintained in a liquid state. Observations of a source of radiation (125I-ferritin) show that the nuclear emulsion used to detect radiation is active under these conditions. Efficiency measurement performed using 125I-ferritin indicate that 125-I-SEM autoradiography is an efficient process that exhibits a 'dose dependent' response. Two types of labeling methods were used with cells, surface labeling with 125I and internal labeling with 3H. Silver grains appeared on labeled cells after autoradiography, removal of residual gelatin and critical point drying. The location of grains was examined on a flagellated green alga (Chlamydomonas reinhardi) capable of undergoing cell fusion. Fusion experiments using labeled and unlabeled cells indicate that 1. Labeling is specific for incorporated radioactivity; 2. Cell surface structure is preserved in SEM autoradiographs and 3. The technique appears to produce reliable autoradiographs. Thus scanning electron microscope autoradiography should provide a new and useful experimental approach.
 ...
PMID:Scanning electron microscope autoradiography of critical point dried biological samples. 725 1

The rat liver after extrahepatic biliary obstruction was studied by SEM and TEM in correlation with basic histochemical techniques. Cholestasis was verified by serological methods. The biochemical data (increase in serum bilirubin values, a gradual lowering of the albumin fraction), in agreement with the ultrastructural results of a sparse RER, suggested a gradual decrease of the protein synthetic activity of the hepatocyte. SEM and TEM revealed numerous fat-storing cells, closely associated with patches of connective fibrils in the subendothelial spaces. Further ultrastructural observations demonstrated: a) a proliferation of the intrahepatic biliary tree (ductular proliferation, including newly formed ducts with sacculation and diverticuli); b) an increased number of canaliculo-ductular junctions and, c) an increase in the length of the bile canalicular network due to its tortuous course, pocketing and side branching. The occurrence of an intact cytoplasmic barrier separating the bile canalicular lumen from the Disse's space together with the results obtained by retrograde infusion of ferritin into the biliary tree suggested that the regurgitation pathway by ductular reabsorption and by transhepatocytic transport is the best documented and most acceptable, at least in the rat.
 ...
PMID:A scanning and transmission electron microscopic study of experimental extrahepatic cholestasis in the rat. 733 53

Iron deficiency is common in hemodialysis patients, particularly if they are on recombinant human erythropoietin (rHuEPO) therapy. Ten anemic patients (hemoglobin concentration 89 +/- 2.2 g/l, mean +/- SEM) on hemodialysis with either storage (serum-ferritin < 60 mg/l) and/or functional (S-transferrin saturation < or = 17%) iron deficiency were followed for 5 weeks. During the first 3 weeks they were given 100 mg of iron dextran on 10 consecutive dialysis sessions. Half of the patients were concomitantly treated with rHuEPO. Iron therapy resulted in a rapid elevation in serum transferrin iron saturation from 11 +/- 1.5% to 80 +/- 7.2% (p < 0.0001), but it decreased to pre-treatment levels within 2 weeks after discontinuation of iron therapy. Serum ferritin concentration increased from 157 +/- 73 mg/l to 434 +/- 105 mg/l during iron therapy (p < 0.0001). In spite of this only 4 patients (2 rHuEPO treated) responded and had a hemoglobin increment > 10 g/l. In the whole group serum transferrin receptor (TfR) levels remained stable, but increased after the cessation of iron dextran only in the rHuEPO treated patients (p < 0.01). In the responders the TfR levels were higher during iron therapy than in the nonresponders (p < 0.02). In an attempt to explain the resistance to iron therapy, serum concentrations of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1b (IL-1b) were also analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Iron availability is transiently improved by intravenous iron medication in patients on chronic hemodialysis. 861 62

The cardiotoxicity of doxorubicin (DOX) and other quinone-containing antitumor anthracyclines has been tentatively attributed to the formation of drug semiquinones which generate superoxide anion and reduce ferritin-bound Fe(III), favoring the release of Fe(II) and its subsequent involvement in free radical reactions. In the present study NADPH- and DOX-supplemented cytosolic fractions from human myocardial biopsies are shown to support a two-step reaction favoring an alternative mechanism of Fe(II) mobilization. The first step is an enzymatic two-electron reduction of the C-13 carbonyl group in the side chain of DOX, yielding a secondary alcohol metabolite which is called doxorubicinol (3.9 +/- 0.4 nmoles/mg protein per 4 h, mean +/- SEM). The second step is a nonenzymatic and superoxide anion-independent redox coupling of a large fraction of doxorubicinol (3.2 +/- 0.4 nmol/mg protein per 4 h) with Fe(III)-binding proteins distinct from ferritin, regenerating stoichiometric amounts of DOX, and mobilizing a twofold excess of Fe(II) ions (6.1 +/- 0.7 nmol/mg protein per 4 h). The formation of secondary alcohol metabolites decreases significantly (Pi < 0.01) when DOX is replaced by less cardiotoxic anthracyclines such as daunorubicin, 4'-epi DOX, and 4-demethoxy daunorubicin (2.1 +/- 0.1, 1.2 +/- 0.2, and 0.6 +/- 0.2 nmol/mg protein per 4 h, respectively). Therefore, daunorubicin, 4'-epi DOX, and 4-demethoxy daunorubicin are significantly (P < 0.01) less effective than DOX in mobilizing Fe(II) (3.5 +/- 0.1, 1.8 +/- 0.2, and 0.9 +/- 0.3 nmol/mg protein per 4 h, respectively). These results highlight the formation of secondary alcohol metabolites and the availability of nonferritin sources of Fe(III) as novel and critical determinants of Fe(II) delocalization and cardiac damage by structurally distinct anthracyclines, thus providing alternative routes to the design of cardioprotectants for anthracycline-treated patients.
 ...
PMID:Secondary alcohol metabolites mediate iron delocalization in cytosolic fractions of myocardial biopsies exposed to anticancer anthracyclines. Novel linkage between anthracycline metabolism and iron-induced cardiotoxicity. 770 66

A recently introduced test measures the concentration of transferrin receptor (TfR) in serum, which increases shortly after the onset of iron deficiency. In adults this increase reflects the degree to which tissue iron availability is impaired. We developed a fluoroimmunoassay to quantify TfR. The purpose of this study was to evaluate the role of TfR as an index of iron sufficiency in 62 healthy prepubertal or early pubertal boys. The mean concentration of serum TfR was 3.8 (-1 SEM = 3.6, +1 SEM = 3.9) mg/L. No associations were observed between the serum TfR and the concentration of Hb, the values of packed cell volume, reticulocyte production index, mean corpuscular Hb, mean corpuscular volume, or the concentrations of serum iron, transferrin, or ferritin. Because none of the subjects had signs of iron deficiency, we determined the 95% reference intervals for Hb, red blood cell indices, and the above-mentioned serum concentrations. The reticulocyte count and reticulocyte production index were higher than expected. Our results indicated that the individual concentration of TfR in serum does not depend on any of the several other parameters of iron status in a group of healthy individuals.
 ...
PMID:Serum transferrin receptor for assessment of iron status in healthy prepubertal and early pubertal boys. 813 70


<< Previous 1 2 3 4 5 6 7 Next >>