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)

Laboratory evidence of suboptimal iron status is endemic in chronically training athletes, yet the importance of low serum ferritin values to athletic performance is unclear. The purpose of this study was to monitor iron status in nine male elite swimmers during and after a 3-week training camp at 2225 m altitude. Values for hemoglobin, hematocrit, serum iron, serum transferrin, and transferrin saturation were within the normal range and remained unchanged over the 54-day monitoring period. Serum ferritin level was significantly decreased by day 13 and continued to decline over the period at altitude. Significant recovery was observed by day 35, by which the workload and altitude were reduced. Reticulocyte counts were raised above normal values by the fifth day at altitude and remained elevated for the duration of the study, indicating increased erythropoiesis. In contrast, neither ferritin levels nor reticulocyte counts were changed in six of the nine subjects after 1 month's training at 1000 m. Food histories revealed dietary iron intakes two to three times as great as the recommended dietary allowance for iron. The draw on body iron reserves observed in this study over the heavy training period at moderate altitude indicates that adequate iron stores are necessary to provide a reservoir of iron during periods of increased iron utilization or loss. Further work is required to elucidate the sources and endpoints of the observed iron flux.
J Lab Clin Med 1992 Sep
PMID:Training at moderate altitude: iron status of elite male swimmers. 151 79

Red cells (RBCs) of individuals with the In(Lu) gene are characterized by suppression of the Lutheran, P1, i, and other blood group antigens, acanthocytosis, and abnormal electrolyte metabolism. To determine the clinical significance of these abnormalities, the survival of autologous RBCs was determined by 51Cr in two siblings with the dominant Lu(a-b-) [In(Lu)] phenotype. Both subjects studied had normal hemoglobin, hematocrit, reticulocyte count, haptoglobin, and ferritin values. RBC indices were mildly hypochromic. Examination of the peripheral smear showed mild acanthocytosis in one individual. Analysis of RBC distribution on discontinuous density gradients showed a shift to lighter fractions than normal control RBCs. Storage of these Lu (a-b-) RBCs at 4 degrees C showed significant hemolysis within a few days; this was confirmed by increased autohemolysis, which was reduced by glucose and ATP. RBC cation content (sodium and potassium) was higher than that in control cells, which indicated increased cell hydration, which explains the lighter density and mild hypochromia of the Lu(a-b-) RBCs. 51Cr survival of autologous Lu(a-b-) RBCs was normal in both subjects studied. The data indicate that the morphologic and cation abnormalities of RBCs of persons with the In(Lu) gene are clinically insignificant, as these cells have normal in vivo survival. Such RBCs, however, are susceptible to increased hemolysis in vitro under standard blood banking storage conditions. Individuals of the Lu(a-b-) phenotype, associated with In(Lu), may not be suitable candidates for routine blood donation.
Transfusion 1992 Sep
PMID:In vitro storage and in vivo survival studies of red cells from persons with the In(Lu) gene. 151 24

Erythrocyte ferritin may be a better estimator of iron bioavailability than the conventional markers of iron stores (serum ferritin and transferrin saturation). To investigate the accuracy of these conventional markers in uremic patients compared with erythrocyte ferritin, we studied 29 chronic hemodialysis patients on erythropoietin (EPO) therapy, 18 without EPO therapy, and 22 healthy control subjects. Apart from the red blood cell indices, serum ferritin, transferrin saturation, and erythrocyte ferritin, the analytical study included red blood cell protoporphyrin and plasma aluminum levels. The control group showed erythrocyte ferritin concentrations between 8.3 and 12.5 attograms/cell (95% confidence interval). In the EPO group, red blood cell protoporphyrin correlated negatively with erythrocyte ferritin, but not with serum ferritin or transferrin saturation. In the non-EPO group, serum ferritin, erythrocyte ferritin, and transferrin saturation did not correlate with red blood cell protoporphyrin. Even though erythrocyte ferritin correlated well with serum ferritin in the EPO group (r = 0.61, P = 0.0003), the sensitivity of normal serum ferritin levels (30 to 300 ng/mL) to discard a low erythrocyte ferritin concentration (erythrocyte ferritin less than 7 ag/cell) was 0.53, while the sensitivity of serum ferritin at levels less than 30 ng/mL to indicate an absolute iron deficiency expressed as a low erythrocyte ferritin concentration was 0.28. Only values of serum ferritin and transferrin saturation greater than 300 ng/mL and 35%, respectively, could rule out a relative iron deficiency expressed as a low erythrocyte ferritin and high red blood cell protoporphyrin concentration. Plasma aluminum levels did not correlate with red blood cell protoporphyrin or erythrocyte ferritin levels in either uremic group.(ABSTRACT TRUNCATED AT 250 WORDS)
Am J Kidney Dis 1992 Sep
PMID:Assessment of iron status by erythrocyte ferritin in uremic patients with or without recombinant human erythropoietin therapy. 151 5

Previous studies have proved that a certain acidic isoform of ferritin is specifically synthesized by the placenta and breast-cancer tissue. In this context it has been further reported that the determination of this so-called placental isoferritin (PLF) on the surface of a subset of peripheral lymphocytes is highly specific and sensitive for early stage breast cancer. By use of the monoclonal antibody CM-H-9 and flow cytometry, the levels of placental ferritin (PLF)-positive cells were determined in 133 female patients undergoing surgical excision of a controversial or highly suspicious lesion of the breast detected by mammography. In addition, 61 healthy blood donors served as controls. Values of PLF-positive cells in breast cancer patients differed significantly from those found in women with benign diseases and healthy controls (3.87% vs. 1.55% and 2.02, respectively; p less than 0.00001). Analysis of prognostic factors in breast cancer patients (tumor size, lymph-node status, menopausal status, estrogen receptor status, histologic grading and grading subfactors) revealed significantly higher levels of PLF-positive cells in lymph-node-negative patients compared with node-positive patients (p less than 0.00001). Furthermore, levels of PLF-positive cells showed a significantly negative correlation with tumor size and nuclear polymorphism. In 15 patients who underwent a guide-wire-directed surgical biopsy for a non-palpable, mammographically suspect lesion, 4 cases of cancer correlated with high values of PLF-positive lymphocytes while only 1 patient with a benign histologic result exhibited more than 4% positive cells.
Int J Cancer 1992 Sep 09
PMID:Determination of placental ferritin (PLF)-positive lymphocytes in women in early stages of breast cancer. 152 10

The relationship between iron status and degree of infection by Schistosoma haematobium was examined in 174 schoolchildren from Niger in an area endemic for urinary schistosomiasis. Iron deficiency was defined by a combination of 3 reliable indicators: a low serum ferritin level combined with a low transferrin saturation, a high erythrocyte protoporphyrin level, or both. Hematuria and proteinuria were seen in 76.4% and 79.9% of the children, respectively, while 95.4% excreted eggs (geometric mean egg count of 31.5 eggs/10 ml of urine). Anemia was seen in 59.7% of the subjects. The prevalence of iron deficiency was 47.1%. Anemia was associated with iron deficiency in 57.7% of the cases. Hemoglobin level and transferrin saturation decreased significantly when the degree of hematuria increased, while prevalence of anemia and iron deficiency increased significantly. The hemoglobin level and hematocrit were negatively correlated with egg count, while anemia prevalence increased with increasing egg count. This inverse relationship between degree of infection by s. haematobium and iron status shows a deleterious consequence of urinary schistosomiasis on nutrition and hematopoietic status, which should be considered in the design of nutrition intervention programs.
Am J Trop Med Hyg 1992 Sep
PMID:Consequences of Schistosoma haematobium infection on the iron status of schoolchildren in Niger. 152 42

A 24-year-old woman had been in full remission of an acute myeloid leukaemia since 1988, but she required regular erythrocyte and platelet transfusions for pancytopenia. To counteract a progressive siderophilia due to the transfusions (ferritin levels of about 10,000 ng/ml) deferoxamine was intermittently given intravenously (5 g after each transfusion). Seven months after the start of this treatment the patient was hospitalized because of severe left-sided facial pain as well as reddening and swelling in the periorbital region. As maxillary and frontal sinusitis was suspected, antibiotics were administered (at first three times daily 2.2 g amoxicillin and clavulanic acid, then two times daily 300 mg rifampicin and 200 mg ciprofloxacin). Nonetheless, orbital phlegmon developed within a few days with protrusion and blindness of the left eye necessitating a decompression operation. Material obtained at operation revealed rhinocerebral mucormycosis. After 3 weeks of antimycotic treatment with both amphotericin B (1 mg/kg.d) and flucytosine (150 mg/kg.d) the mucormycosis healed without the necessity of extensive and disfiguring removal of necrotic tissue. But the blindness in the left eye, caused by occlusion of the central artery, was irreversible.
Dtsch Med Wochenschr 1992 Sep 18
PMID:[Rhinocerebral mucormycosis during deferoxamine therapy]. 152 5

The iron-responsive element binding protein (IRE-BP) is a cytosolic protein that binds a highly conserved sequence in the untranslated regions of mRNAs involved in iron metabolism including ferritin, transferrin receptor, and erythroid 5-aminolevulinate acid synthase. This conserved sequence is termed the iron-responsive element and is necessary for the post-transcriptional regulation of these mRNAs by iron. The rat liver IRE-BP was purified to homogeneity by chromatographic methods and partial amino acid sequence was obtained. A cDNA was isolated from a rat liver cDNA library and sequenced. The amino acid sequence deduced from the cDNA sequence corresponds to a protein of 889 amino acids with a predicted molecular weight of 97.946. The NH2-terminal sequence obtained by Edman degradation matched the deduced amino acid sequence obtained from the cDNA, confirming the translational start site. Rat liver IRE-BP shares 95% identity with human IRE-BP and 98% identity with mouse IRE-BP indicating that the IRE-BPs have remained highly conserved during evolution. The 5'-untranslated region is at least 236 nucleotides and contains interesting structural features including two direct repeats, an inverted repeat, and three small open reading frames. The rat IRE-BP mRNA is approximately 3600 nucleotides and is expressed in a variety of rat tissues including liver, spleen, and gut. Over the course of 16 h following an intraperitoneal injection of iron in rats. IRE-BP RNA binding activity decreases to 50% of control levels. The decrease in IRE-BP RNA binding activity in extracts from iron-treated rats is reversible by pretreatment of the extracts with reducing agents. The steady-state levels of IRE-BP mRNA remain constant during iron treatment. These data suggest that the decrease in IRE-BP RNA binding activity by iron in rat liver is due to post-translational changes in the RNA binding affinity of the IRE-BP and not due a decrease in the transcription of the IRE-BP gene or to the destabilization of the IRE-BP mRNA.
J Biol Chem 1992 Sep 15
PMID:The iron-responsive element binding protein. Purification, cloning, and regulation in rat liver. 152 27

Ferritin synthesis is controlled at the translational level in response to cellular iron status. A component of this regulatory system is the ferritin repressor protein (FRP) which binds to the iron-responsive element (IRE) located at the 5' end of all known ferritin mRNAs, thus inhibiting its translation. Antibodies against purified FRP were raised in mouse and used to isolate an FRP cDNA from a rabbit liver cDNA library cloned in the expression vector lambda gt11. The FRP cDNA encodes a 98.5-kilodalton protein which shares greater than 90% identity with IRE-binding proteins from other species. The FRP cDNA was placed under the transcriptional direction of the yeast GAL1 promoter. Yeast transformed with this gene express IRE-specific binding activity, illustrating the potential utility of yeast for the study of FRP structure/function. Analysis of FRP distribution in rabbit tissues shows that it is present in a variety of tissues. The levels of FRP differ dramatically from tissue to tissue, however. An examination of FRP mRNA levels and comparison to FRP protein suggest that synthesis of FRP is regulated transcriptionally and post-transcriptionally.
J Biol Chem 1992 Sep 15
PMID:Cloning of a functional cDNA for the rabbit ferritin mRNA repressor protein. Demonstration of a tissue-specific pattern of expression. 152 28

The role of the protein shell in the formation of the hydrous ferric oxide core of ferritin is poorly understood. A VO2+ spin probe study was undertaken to characterize the initial complex of Fe2+ with horse spleen apoferritin (96% L-subunits). A competitive binding study of VO2+ and Fe2+ showed that the two metals compete 1:1 for binding at the same site or region of the protein. Curve fitting of the binding data showed that the affinity of VO2+ for the protein was 15 times that of Fe2+. Electron nuclear double resonance (ENDOR) measurements on the VO(2+)-apoferritin complex showed couplings from two nitrogen nuclei, tentatively ascribed to the N1 and N3 nitrogens of the imidazole ligand of histidine. The possibility that the observed nitrogen couplings are from two different ligands is not precluded by the data, however. A pair of exchangeable proton lines with a coupling of approximately 1 MHz is tentatively assigned to the NH proton of the coordinated nitrogen. A 30-40% reduction in the intensity of the 1H matrix ENDOR line upon D2O-H2O exchange indicates that the metal-binding site is accessible to solvent and, therefore, to molecular oxygen as well. The ENDOR data provide the first evidence for a principle iron(II)-binding site with nitrogen coordination in an L-subunit ferritin. The site may be important in Fe2+ oxidation during the beginning stages of core formation.
Biochemistry 1991 Sep 24
PMID:Iron binding to horse spleen apoferritin: a vanadyl ENDOR spin probe study. 165 90

Reactions of reduced horse spleen ferritin with horse and Saccharomyces cerevisiae ferricytochromes c, cow ferricytochrome b5, sperm-whale metmyoglobin and Pseudomonas aeruginosa ferricytochrome c-551 were investigated by u.v.-visible spectrophotometry. In all cases the reduced ferritin reduced the ferrihaemoproteins. The rate of reduction varied from less than 0.2 M-1.s-1 for metmyoglobin to 1.1 x 10(3) M-1.s-1 for horse ferricytochrome c (0.1 M-phosphate buffer, pH 7.4, at 25 degrees C). We conclude that the mechanism of ferrihaemoprotein reduction involves long-range electron transfer through the coat of ferritin and that such electron transfer is rapid enough to account for the rates of iron release observed by other workers in reductive release assays.
Biochem J 1991 Sep 15
PMID:Electron transfer between horse ferritin and ferrihaemoproteins. 165 93


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