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

The relationship between iron status and food iron absorption was evaluated in 75 normal volunteers, 15 patients with idiopathic hemochromatosis, and 22 heterozygotes by using double extrinsic radioiron tags to label independently the nonheme and heme iron components of a hamburger meal. In normal subjects, absorption from each of these pools was inversely correlated with storage iron, as measured by the serum ferritin concentration. In patients with hemochromatosis, absorption of both forms of iron was far greater than would be predicted from the relationship between absorption and serum ferritin observed in normal volunteers. Nevertheless, there was still a modest but statistically significant reduction in absorption of nonheme iron with increasing serum ferritin. This relationship could not be demonstrated in the case of heme iron absorption. In heterozygotes, nonheme iron absorption from a hamburger meal containing no supplementary iron did not differ significantly from that observed in normal volunteers. However, when this meal was both modified to promote bioavailability and supplemented with iron, absorption of nonheme iron was significantly elevated. These studies confirm the presence of excessive nonheme iron absorption even from unfortified meals in patients with idiopathic hemochromatosis and suggest in addition that they are particularly susceptible to iron loading from diets containing a high proportion of heme iron. Impaired regulation of nonheme iron absorption was also observed in heterozygous individuals, but a statistically significant abnormality was demonstrable only when the test meal contained a large highly bioavailable iron supplement.
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PMID:Food iron absorption in idiopathic hemochromatosis. 280 57

Rats fed a carbonyl iron-supplemented diet for 4-15 months were studied for iron content and morphologic changes in the liver, spleen, intestinal mucosa, pancreas and heart. All organs had an increased iron content measured by atomic absorption, with the highest concentrations in the liver and spleen. The periportal distribution of stored iron in the liver was similar to that in human hemochromatosis. In animals treated beyond 6 months Kupffer cells and sinusoidal lining cells also showed cytosiderosis. Electron microscopy provided information on ferritin and hemosiderin content and distribution within parenchymal and sinusoidal cells of the liver but no excessive fibrosis was found. Except for the spleen, the other organs showed less iron deposition. Iron-filled lysosomes (siderosomes) were found in macrophages in the intestinal lamina propria and pancreas, as well as in enterocytes, pancreatic acinar cells and heart muscle cells. Heavily iron-laden siderosomes had increased membrane instability which was demonstrated both morphologically and by measurements of latent lysosomal enzyme activities. Even though cirrhosis was not found, the distribution pattern of accumulated storage iron and lysosomal lability indicated that the carbonyl iron-fed rat is a suitable experimental model for human hemochromatosis.
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PMID:Ultrastructural observations in the carbonyl iron-fed rat, an animal model for hemochromatosis. 289 Feb 33

This study was undertaken to assess the relationship between iron absorption and the concentration of duodenal iron proteins in normal subjects and patients with idiopathic hemochromatosis (IH). Biopsies were obtained endoscopically from the duodenum in 17 normal subjects, 3 of whom were mildly iron deficient, and 7 patients with untreated IH. The absorption of both heme and nonheme iron was increased in IH despite a 20-fold elevation in serum ferritin. Immunoassays using MAb were used to measure transferrin, H-rich ferritin, and L-rich ferritin in mucosal samples. Mucosal transferrin concentrations in normal subjects did not correlate with either iron status or iron absorption, indicating that mucosal transferrin plays no physiological role in iron absorption. Mucosal transferrin was significantly lower in IH, presumably because of a decrease in mucosal transferrin receptors. Mucosal H and L ferritin concentrations were directly related to body iron stores and inversely related to iron absorption in normal subjects. In IH, mucosal H and L ferritin failed to increase in parallel with the serum ferritin, but were appropriate for the level of iron absorption. The relationship of mucosal H/L ferritin in IH did not differ from that observed in normal subjects. Our findings indicate that the major abnormality in duodenal iron proteins in IH is a parallel decrease in the concentration of H- and L-rich ferritin. It is not evident whether this is the result or the cause of the absorptive abnormality.
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PMID:Duodenal iron proteins in idiopathic hemochromatosis. 291 Sep 11

The authors have investigated the hypothesis that neonatal hemochromatosis (NH), a generally fatal disease of infancy, is due to abnormalities in cellular response to ambient levels of iron. The clinical and necropsy findings in two infants with NH, the results of evaluations for iron-storage disease in their first-degree relatives, and the results of the authors' studies of ferritin and transferrin-receptor (TfR) synthesis in NH and normal fibroblasts are presented. No differences between cultured skin fibroblasts from a normal infant and similar cells from the two infants with NH were seen with respect to TfR and ferritin synthesis rates or their modulation by iron. NH and adult idiopathic hemochromatosis (AH) share a pattern of siderosis in which epithelial and mesenchymal elements contain large quantities of stainable iron, while reticuloendothelial elements contain almost none. Although no familial correlation between NH and AH has been established, and none appeared to exist in these two families, the authors' results parallel those of previous studies of various cell types from persons with AH. The abnormalities in cellular iron handling, undefined at present, that are associated with the phenotype common to NH and AH do not appear primarily to involve the regulation by iron of rates of TfR and ferritin synthesis.
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PMID:Neonatal hemochromatosis. The regulation of transferrin-receptor and ferritin synthesis by iron in cultured fibroblastic-line cells. 291 54

Idiopathic hemochromatosis is a hereditary disease that is associated with human leucocytic antigens A3, B7, and B14. A genetic association between human leucocytic antigen-linked hemochromatosis and idiopathic refractory sideroblastic anemia has been suggested that may predispose some patients with idiopathic refractory sideroblastic anemia to develop gross iron overload. Study of the family of a patient with idiopathic refractory sideroblastic anemia and hemochromatosis revealed that 2 of 5 first-degree relatives had significant elevations of serum ferritin, and a shared human leucocytic antigen haplotype, supporting the concept that patients with idiopathic refractory sideroblastic anemia and significant iron overload have at least one allele for hemochromatosis.
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PMID:Iron overload complicating sideroblastic anemia--is the gene for hemochromatosis responsible? 292 65

Thirteen men and one woman (mean age 48.8 yr +/- 6.9, range 36-63) with idiopathic hemochromatosis were treated by erythrocytapheresis. Iron depletion followed 9.60 months treatment (median 24), with 21-203 erythrocytaphereses (mean 93 +/- 61) and total iron removal of 4.2-40.6 g (mean 19 +/- 11.9). Trasferrin saturation decreased from 90 +/- 8.7% to 17 +/- 10.6% and serum ferritin from 3164 micrograms/L +/- 1488 to 60.5 micrograms/L +/- 77.5, and liver iron content normalized in all cases. Initial serum ferritin in the patients who were iron-depleted at 18 months (50%, cumulative percentage) was significantly lower than in those still iron loaded at that time (2280 micrograms/L +/- 940 vs 4049 micrograms/L +/- 1444, p less than 0.02). Clinical improvement was noted in all cases with about a 30% decrease in insulin requirement in most diabetics. Thus erythrocytapheresis appears to be effective and safe in obtaining iron depletion in idiopathic hemochromatosis.
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PMID:Effectiveness of erythrocytapheresis in idiopathic hemochromatosis. Report of 14 cases. 292 63

In humans, the H (heavy) and L (light) chains of the iron-storage protein ferritin, are derived from multigene families. We have examined the chromosomal distribution of these H and L sequences by Southern analysis of hybrid cell DNA and by chromosomal in situ hybridization. Our results show that human ferritin H genes and related sequences are found on at least seven different chromosomes while L genes and related sequences are on at least three different chromosomes. Further, we have mapped the chromosomal location of expressed genes for human H and L ferritin chains and have found an H sequence which may be a useful marker for idiopathic hemochromatosis.
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PMID:Human ferritin H and L sequences lie on ten different chromosomes. 303 71

To test the hypothesis that deficiencies in hypothalamic-pituitary function in genetic hemochromatosis result from cellular injury by iron deposits, we conducted provocative tests in 11 men with genetic hemochromatosis before and after iron depletion by serial phlebotomy and in 10 control subjects. We gave combination intravenous injections of insulin (0.15 U/kg), luteinizing hormone releasing hormone (LHRH, 100 micrograms), and thyrotropin releasing hormone (400 micrograms) and then measured plasma glucose, growth hormone, corticosteroids, follicle-stimulating hormone, luteinizing hormone, prolactin, and thyroid-stimulating hormone at 30-minute intervals for 90 minutes. Phlebotomy caused a substantial decrease in median values for serum ferritin, deferoxamine-chelatable iron, and hepatic iron concentration. Before phlebotomy, stimulation by hypoglycemia and thyrotropin releasing hormone caused significantly less secretion of growth hormone (P = 0.004) and prolactin (P = 0.03) in patients than in control subjects. No significant improvement was noted, however, in growth hormone or prolactin secretion after phlebotomy. Of the 11 patients, 7 had secondary hypogonadism, and phlebotomy did not improve the serum testosterone, follicle-stimulating hormone, luteinizing hormone, or responses to LHRH in any case. Chlorpromazine injections failed to elevate serum prolactin in all patients, and administration of levodopa caused a partial reduction in serum prolactin; thus, the hypothalamus may be an important locus of endocrine malfunction in these patients. We conclude that abnormal hypothalamic-pituitary function in genetic hemochromatosis is not substantially improved by iron-depletion therapy.
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PMID:Influence of phlebotomy treatment on abnormal hypothalamic-pituitary function in genetic hemochromatosis. 310 26

The gene coding for idiopathic hemochromatosis is prevalent in Sweden, the country with the highest iron fortification of food (42%) in the world. We wanted to study if this highly iron-fortified diet had negative effects on the iron situation in carriers of the iron-loading genes. Iron stores averaged 6.7 grams in male homozygotes who were mainly identified through laboratory screening. It was 3.4 grams in female homozygotes. By HLA typing of family members of these homozygous probands, 39 additional homozygotes and 172 heterozygotes were detected. Serum ferritin averaged 620 micrograms/l in 20 male and 168 micrograms/l in 19 female homozygotes in the family screening. Storage iron as measured by serum ferritin concentration was slightly but significantly higher in male heterozygotes than controls (117 micrograms/l versus 87 micrograms/l, p less than 0.02). There was no further increase in serum ferritin concentration with age after 40 years. Heterozygotes showed no clinical signs of iron damage. These findings do not indicate that carriers of the iron-loading genes in Sweden have been adversely affected by the highly iron-fortified diet of the country.
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PMID:The effect of iron fortification of the diet on clinical iron overload in the general population. 316 2

Transferrin saturation was determined in 11,431 men and 10,639 women aged 15 or more drawn from different areas in southern and central Finland and attending a multiphasic health screening examination in 1967-1972. All the 163 men and 66 women with transferrin saturation greater than or equal to 70% at the initial examination and still alive at the end of 1983 were invited to a re-examination. Of the invited persons, 76% attended the re-examination. Transferrin saturation and serum ferritin were the initial screening methods in the re-examination. All persons with suspected hemochromatosis were clinically examined and a laparoscopy was performed. Four men and four women were found with unequivocal hemochromatosis. Only one of these cases was diagnosed beforehand. According to these data the prevalence of hemochromatosis in Finland is about 50/100,000.
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PMID:Prevalence of hemochromatosis in Finland. 318 89


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