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

This paper addresses the question of whether abnormalities in ferritin expression in the iron storage disease hemochromatosis (HC) involve major deletions or alterations in regions containing the two ferritin H genes that lie near the disease locus on chromosome 6p. We present evidence from analyses of Southern blots that neither gene is deleted in hemochromatosis. We also describe a polymorphism in one of the genes that we have previously shown to be a processed pseudogene. This polymorphism does not correlate with the presence of HC. The PIC value for this polymorphism was calculated as 0.49.
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PMID:Polymorphism in a ferritin H gene from chromosome 6p. 167 57

To assess the clinical value of human leukocyte antigen typing in the diagnosis and management of hereditary hemochromatosis, 105 siblings of 35 proband cases of hemochromatosis were retrospectively analyzed to study whether the exclusion of human leukocyte antigen typing would have adversely affected management. All siblings and probands had already been tested for human leukocyte antigen-A and human leukocyte antigen-B typing, serum ferritin and transferrin saturation. The median age of siblings was 55 yr (range = 11 to 82). Siblings were categorized according to putative genotype (homozygote, heterozygote and normal) using human leukocyte antigen typing. Phenotypic expression of hemochromatosis was considered to be iron overload as indicated by an elevated ferritin (male = greater than 350 micrograms/L, female = greater than 200 micrograms/L) and/or transferrin saturation (greater than 55%). Six of 37 homozygotes had a normal ferritin and transferrin saturation, with five of these patients under 32 yr old. No putative heterozygotes with both an abnormal ferritin and transferrin saturation were seen, although 12 of 48 (25%) heterozygotes had either an elevated ferritin or transferrin saturation. Twenty of 20 normal siblings had a normal ferritin and transferrin saturation. To assess the cost of screening with and without human leukocyte antigen typing, a cost model simulation was used that compared the costs of both methods in a hypothetical family (proband, homozygote, heterozygote and normal sibling).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Human leukocyte antigen typing of siblings in hereditary hemochromatosis: a cost approach. 173 29

To further evaluate a possible abnormality in the reticuloendothelial cells in hemochromatosis, the binding of a monoclonal anti-human liver ferritin antibody to monocytes was studied in 19 patients with hemochromatosis, 8 patients with secondary iron overload, 1 patient with hyperferritinemia without iron overload, and 15 normal volunteers. Binding of the antibody to the monocytes was analyzed using a fluorescence-activated cell sorter (FACS). Binding of the anti-ferritin antibody to monocytes was demonstrated in 34.7 +/- 4.5% (mean +/- standard error) of the monocytes in untreated hemochromatosis patients (mean serum ferritin = 2294 +/- 415 micrograms/L), 6.75 +/- 2.03% in treated hemochromatosis patients (mean serum ferritin = 263 +/- 85 micrograms/L), 12.3 +/- 2.7% of the monocytes in the secondary iron overload patients (mean serum ferritin = 2476 +/- 867 micrograms/L), 4.1% in the patient with hyperferritinemia (serum ferritin = 1192) and 4.1 +/- 0.5% of the monocytes in the normal volunteers (mean serum ferritin = 55.2 +/- 11.9 micrograms/L). % binding of anti-ferritin antibody was significantly greater in hemochromatosis patients compared to patients with secondary iron overload (p less than 0.05) despite a comparable degree of iron overload in the secondary iron overload group. The addition of exogenous human ferritin to samples from treated hemochromatosis patients and normal volunteers did not significantly increase the % of monocytes binding anti-ferritin antibody. These results suggest that monocytes from iron-loaded hemochromatosis patients express increased surface ferritin which may represent release of ferritin and a metabolic defect characteristic of hemochromatosis.
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PMID:Monocyte membrane ferritin in hemochromatosis. 174 18

The clinical features and therapy of chronic iron overload are reviewed. Chronic iron overload is classified as primary or secondary hemochromatosis. In primary hemochromatosis a genetic defect in iron metabolism results in increased absorption of iron from the gastrointestinal tract. The excess iron in secondary hemochromatosis may be derived from increased gastrointestinal absorption due to ineffective erythropoiesis or from medicinal, dietary, or transfusional sources. Phlebotomy is the treatment of choice in patients with primary hemochromatosis. Iron chelation therapy is indicated in patients who are not candidates for phlebotomy. Deferoxamine mesylate, the only commercially available iron chelator, is usually administered subcutaneously or intravenously over 10-12 hours/day. Serum ferritin concentrations are measured every three to six months to monitor the effectiveness of therapy. The adverse effects of deferoxamine include local skin reactions, ototoxicity, cataracts, growth impairment, and increased susceptibility to infectious organisms. Patient compliance may be compromised by the routes of administration and cost of deferoxamine. Early detection and prompt treatment are necessary to prevent organ damage. Phlebotomy and iron chelation therapy are effective in the treatment of chronic iron overload.
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PMID:Treatment of chronic iron overload. 174 62

What then are the lessons to be learned about prevention and treatment of hemochromatosis? Early diagnosis is essential. The best indicator would be testing of serum iron and total saturation followed by a serum ferritin if elevated. Once these indices are abnormally high, MRI and or a liver biopsy should confirm the stage of the iron over-loaded state. If indeed the patient is not iron-overloaded (normal liver biopsy in the face of high saturation and ferritin level) phlebotomies should be performed until these indices are normal and then maintained at a normal level. This should entail four to six phlebotomies a year. Family members should also be screened and managed in a like manner. HLA typing may be a partially helpful screening device. The abnormal gene is closely linked on chromosome 6 with HLA histocompatibility loci. Now, by means of HLA typing, we can identify heterozygote carriers and homozygous (abnormal) among first degree relatives of patients with hemochromatosis. Unfortunately, HLA typing can only be used within a given family and cannot be used to screen the general population. It is estimated that 70% of hemochromatoics have the antigen HLA-A3; however, so does 28% of the (well) general population. Patients with unexplained cirrhosis, arthritis, liver disease, diabetes, impotency, cardiomyopathy and neurological symptoms should be screened in a like manner. Routine health practice profile chemistries must include a serum iron and iron saturation, and if high followed by a serum ferritin. Once diagnosed, therapy must be maintained with phlebotomy for the life time of the patient.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hemochromatosis: diagnosis and treatment. 179 61

Iron is essential for life, but iron overload is toxic and potentially fatal. The liver is a major site of iron storage and is particularly susceptible to injury from iron overload, especially when (as in primary hemochromatosis) the iron accumulates in hepatocytes. Iron can be taken up by the liver in several forms and by several pathways including: (1) receptor-mediated endocytosis of diferric or monoferric transferrin or ferritin, (2) reduction and carrier-facilitated internalization of iron from transferrin without internalization of the protein moiety of transferrin, (3) electrogenic uptake of low molecular weight, non-protein bound forms of iron, and (4) uptake of heme from heme-albumin, heme-hemopexin, or hemoglobin-haptoglobin complexes. Normally, pathway 2 is probably the major one for uptake of iron by hepatocytes. Iron is stored in the liver in the cores of ferritin shells and as hemosiderin, an insoluble product derived from iron-rich ferritin. Iron in hepatocytes stimulates translation of ferritin mRNA and represses transcription of DNA for transferrin and transferrin receptors. The major pathologic effects of chronic hepatic iron overload are: (1) fibrosis and cirrhosis, (2) porphyria cutanea tarda, and (3) hepatocellular carcinoma. Although precise pathogenetic mechanisms remain unknown, iron probably produces these and other toxic effects by increasing oxidative stress and lysosomal lability. Vigorous efforts at diagnosis and treatment of iron overload are essential since the pathologic effects of iron are totally preventable by early vigorous iron removal and prevention of iron re-accumulation.
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PMID:Iron and the liver. 184 76

To assess whether an abnormality in transferrin receptor expression or regulation could represent an underlying metabolic defect in the reticuloendothelial (RE) system in hemochromatosis, monocytes were analyzed for the expression of the transferrin receptor using a monoclonal antibody (Act II) to the transferrin receptor (CD71) and flow cytometric analysis. Hemochromatosis patients (n = 14), and normal volunteers with no clinical evidence of iron overload (n = 14) were studied. A significant inverse relationship was observed for the relationship between the expression of transferrin receptor on monocytes and log(hepatic iron concentration) in hemochromatosis patients (r = -0.59, P less than .02) and also for the relationship between the expression of transferrin receptor and log(serum ferritin) in normal volunteers (r = -0.90, P less than .001). There was no significant difference in the mean expression of monocyte transferrin receptor between hemochromatosis patients and normal volunteers. However, the expression of the transferrin receptor in hemochromatosis patients was disproportionately higher than would be predicted from the relationship between serum ferritin and transferrin receptor expression in normal volunteers. The inverse relationship of the monocyte transferrin receptor relative to body iron stores in hemochromatosis is consistent with observations in other tissues, and suggests that non-transferrin iron metabolism, including ferritin, requires further investigation in the RE cell in hemochromatosis.
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PMID:Expression of transferrin receptors on monocytes in hemochromatosis. 185 81

The therapeutic management of patients with idiopathic hemochromatosis (IH) requires an accurate estimate of hepatic iron overload in order to prevent tissue fibrosis and organ failure. Magnetic resonance imaging (MRI) was used to estimate liver iron overload in 5 patients with IH and in 8 normal controls. Signal intensity ratio between liver and subcutaneous fat in T1-, proton- and T2-weighted images was significantly lower in IH when compared with normal controls, and increased gradually during treatment by phlebotomy. Mean serum ferritin at diagnosis was 755 micrograms/l (range: 648-900) in IH and 85 micrograms/l (range: 19-232) in normal controls. A high correlation (r = -0.93) was present between liver signal intensity ratio and serum ferritin; both changed in parallel during removal of iron by phlebotomy. MRI may provide a safe and accurate method of detecting iron overload in the precirrhotic phase of IH, obviating the need for liver biopsy. It may also be used to monitor treatment.
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PMID:Magnetic resonance imaging in idiopathic hemochromatosis. 191

Although many studies have examined the regulation of transferrin, transferrin receptor and ferritin subunit gene expression in experimental systems, no molecular biological data in humans have been documented to date. In this study we simultaneously analyzed the hepatic content of transferrin, transferrin receptor and heavy and light ferritin subunit messenger RNAs in tissue samples obtained from subjects with normal iron balance and patients with primary or secondary iron overload. Steady-state levels of transferrin messenger RNA were not depressed by iron overload. On the contrary, they were increased (p less than 0.001) in patients with severe hepatic siderosis (liver iron content greater than 200 mumol/gm dry wt) as compared with the control group. This indicates that, as already suggested by our previous data in experimental siderosis, iron maintains the ability to induce transferrin gene activity even when cellular iron content is significantly increased. Transferrin receptor gene expression was found to respond in the same manner to any cause of iron-tissue load, regardless of the cause. In fact, a lower signal for transferrin receptor messenger RNA was consistently detected in iron-overloaded patients vs. control subjects, particularly in patients with thalassemia major and idiopathic hemochromatosis (p less than 0.001). Ferritin light-subunit messenger RNA accumulation was significantly increased in those patients with severe siderosis (idiopathic hemochromatosis and thalassemia major = liver iron between 200 and 600 mumol/gm dry wt). The fact that no significant change in hepatic ferritin heavy-subunit gene expression was detected in iron-loaded patients confirms preferential production of light-subunit--enriched ferritins in long-term iron overload.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Regulation of hepatic transferrin, transferrin receptor and ferritin genes in human siderosis. 195 58

The findings in the cord blood sample of an infant from a treated hemochromatotic mother of a raised transferrin saturation (88%) and a raised ferritin concentration (250.2 micrograms/L) together with elevated maternal values (66% and 91.6 micrograms/L, respectively) yet a normal total placental iron content (26.9 mg) suggested that in common with gastrointestinal mucosal cells and reticuloendothelial cells in hemochromatosis, the placental cell may exhibit an abnormality of iron storage and transport.
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PMID:Maternal and fetal iron measurements in a hemochromatotic pregnancy. 195 10


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