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PubMed1988

Rapid excretion of gallium-67 isotope in an iron-overloaded patient receiving high-dose intravenous deferoxamine.

A 23 year-old black male with homozygous sickle cell disease (Hb SS disease) and transfusional iron overload was admitted for evaluation of response to intravenous deferoxamine (DFO) therapy. Soon after admission, the patient suffered an intraventricular hemorrhage and during his subsequent hospitalization developed a persistent fever of undetermined origin (f.u.o.). Included in the diagnostic evaluation of fever was a gallium 67 scan (Ga-67), which was initially nondiagnostic because of Ga-67 citrate's preferential chelation by DFO. After DFO was discontinued, a repeat scan demonstrated a lesion above the left kidney. To our knowledge the unusual interaction in vivo of DFO with Ga-67 citrate has not been reported in the clinical literature. With the anticipated increased use of chelation therapy for patients with transfusional iron overload, this interaction may be encountered more frequently. DFO should be discontinued before the use of Ga-67 scanning in this clinical situation, or an alternative isotopic scan, such as indium-labelled white cells, should be considered.

Adult↗
PubMed1990

Congenital sideroblastic anemia without clinical iron overload. A case report.

An 18 year old boy presented with microcytic hypochromic anemia. Erythrocytic abnormalities and family studies suggested congenital sideroblastic anemia (CSA), but atypical features included absence of clinical iron overload, scanty iron deposits in mitochondria of late erythroblasts and reticulocytes, and a high platelet count. An unusual adhesion between bone marrow macrophages and reticulocytes was observed by electron microscopy. Haematological response was seen following pyridoxine administration, thus fending support to the diagnosis of CSA.

Adolescent↗
PubMed2003

Screening for iron overload in the Turkish population.

BACKGROUND/AIMS: Hereditary hemochromatosis (HH), the most common autosomal recessive disease in the white population, is characterized by excessive gastrointestinal absorption of iron and loading of parenchymal organs. HFE mutations of C282Y and H63D are largely responsible for HH in populations of Celtic ancestry. Although many screening studies related to HH have been done in Northern Europe, the USA and Australia, as yet, no such study has been published on Turkey. In this study we aimed to screen the Turkish population for iron overload. METHODS: Random samples were obtained from 4,633 healthy adults (3,827 male, 806 female, mean age +/- SD 35 +/- 8 years, range 14-76) for the measurement of transferrin saturation (TS). Measurements were repeated after an overnight fast in the subjects whose initial TS was > or =50%. Serum ferritin levels and C282Y and H63D gene mutations were studied in cases when fasting TS was > or =50%. In cases where the serum ferritin level was >200 ng/ml with or without HFE mutations, liver biopsy was performed for histological evaluation and determination of iron content. RESULTS: In 158 subjects, TS was > or =50% in the non-fasting state. A second determination of TS after an overnight fast was performed in 135 subjects. In 26 subjects, the TS was > or =50% in the fasting state. HFE mutation and serum ferritin levels were measured in these 26 subjects. Eleven subject (10 male, 1 female) were heterozygote and 1 male subject was homozygote in reference to H63D. C282Y mutation was not found. Four of these 26 subjects (all males, aged 23, 24, 40, 49) had increased serum ferritin levels and liver biopsy was performed. In 1 male (aged 49) who was heterozygote for H63D genotype with a serum ferritin level of 645 ng/ml, iron overload in liver tissue was shown by histology as well as atomic absorption spectrophotometry. CONCLUSION: The prevalence of hemochromatosis in the Turkish population is much lower in comparison to populations of Celtic ancestry and C282Y mutation is non-existent.

Adolescent↗
PubMed1985

Nuclear magnetic resonance study of iron overload in liver tissue.

Whole-tissue and homogenized samples of human liver were studied in a NMR spectrometer, T1 and T2 relaxation times were measured as a function of added inorganic or organic iron. When inorganic iron (Fe+3) was added, pronounced T1 and T2 shortening was noted. However, when organic iron, in the form of ferritin, was added, the amount of T1 and T2 relaxation enhancement was much reduced for the same amount of added iron. The in vitro ferritin results model the situation found in clinical studies of hemochromatosis. Only in cases of severe iron overload were significant decreases in relaxation times observed. The T2 relaxation time was the more reliable indicator of excessive levels of iron in the liver. The large range of T1 and T2 values encountered in normal volunteers precludes the use of MR to quantitatively measure iron levels in the liver. The T1 and T2 relaxation times measured at intervals for one individual tend to fluctuate as well, making the use of MR to follow the course of treatment of iron overload disorders unreliable.

Hemochromatosis↗
PubMed1988

Reduction in liver iron in hemodialysis patients with transfusional iron overload by deferoxamine mesylate.

Four hemodialysis patients with transfusional iron overload were treated with three times weekly intravenous (IV) deferoxamine mesylate during the dialysis treatment. Using a gamma ray scattering technique, significant reductions in liver iron content were documented, with a mean follow-up of 20 months. Three of the four patients showed significant improvements in liver enzymes. This decrease in liver iron content could not be predicted by clinical parameters or serum ferritin. Therapy proved to be safe and effective, but follow-up requires monitoring of tissue iron by means other than standard laboratory tests.

Adult↗
PubMed2002

GRACILE syndrome, a lethal metabolic disorder with iron overload, is caused by a point mutation in BCS1L.

GRACILE (growth retardation, aminoaciduria, cholestasis, iron overload, lactacidosis, and early death) syndrome is a recessively inherited lethal disease characterized by fetal growth retardation, lactic acidosis, aminoaciduria, cholestasis, and abnormalities in iron metabolism. We previously localized the causative gene to a 1.5-cM region on chromosome 2q33-37. In the present study, we report the molecular defect causing this metabolic disorder, by identifying a homozygous missense mutation that results in an S78G amino acid change in the BCS1L gene in Finnish patients with GRACILE syndrome, as well as five different mutations in three British infants. BCS1L, a mitochondrial inner-membrane protein, is a chaperone necessary for the assembly of mitochondrial respiratory chain complex III. Pulse-chase experiments performed in COS-1 cells indicated that the S78G amino acid change results in instability of the polypeptide, and yeast complementation studies revealed a functional defect in the mutated BCS1L protein. Four different mutations in the BCS1L gene have been reported elsewhere, in Turkish patients with a distinctly different phenotype. Interestingly, the British and Turkish patients had complex III deficiency, whereas in the Finnish patients with GRACILE syndrome complex III activity was within the normal range, implying that BCS1L has another cellular function that is uncharacterized but essential and is putatively involved in iron metabolism.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2004

Long-term alpha interferon treatment is effective on anaemia and significantly reduces iron overload in congenital dyserythropoiesis type I.

Interferon has been shown to be an effective treatment of congenital dyserythropoiesis type I (CDA-I), but the optimal dose and the feasibility of this treatment remains to be determined. Here, in a 9-yr follow-up of a single patient, we show that interferon remains active during such a long period. The optimal dose of conventional alpha interferon could be evaluated at 2 million units twice a week. Pegylated interferon could be used as well at a dose of 30 microg/wk. During interferon treatment, serum and erythrocyte ferritin levels decreased progressively, and remained inversely correlated with haemoglobin levels. On repeated liver biopsies, iron overload could be normalized. Low dose interferon is a long-term treatment of CDA-I, and allows a significant decrease in iron overload, that could be interesting even in patients who are only moderately anaemic.

Adult↗
PubMed2003

MRI detection of ferritin iron overload and associated neuronal pathology in iron regulatory protein-2 knockout mice.

Genetic ablation of iron regulatory protein 2 (IRP-2), a protein responsible for post-transcriptional regulation of expression of several iron metabolism proteins, predisposes IRP-2 -/- mice to develop adult onset neurodegenerative disease. Ferric iron reproducibly accumulates within axonal tracts and neuronal cell bodies in discrete regions of the brain, and areas of iron accumulation colocalize with areas of high ferritin expression. To better evaluate the onset and progression of neurodegeneration in IRP-2 -/- mice, we performed a high-resolution magnetic resonance imaging study comparing live, age-matched wild-type and IRP-2 -/- mice, using an 11.7-Tesla magnet and a custom-designed head coil. The mice were perfused after imaging, and iron stains and immunohistochemical studies were performed. We detected increases in the number of pixels with low T(2) values expected from accumulations of iron in IRP-2 -/- mice. Moreover, in several areas of the brain, including the substantia nigra and the superior colliculus, we detected areas with unusually high T(2) values that likely represented accumulation of water. On histopathological examination we discovered relatively small vacuoles in these brain regions of IRP-2 -/- mice. Our ability to gather T(2) data within regions of interest enabled us to define a bimodal T(2) intensity pattern that likely represents both ferritin iron accumulation and its associated pathological consequences within the brain. Our discoveries may have significant applications for the diagnosis and treatment of human diseases if such high-resolution techniques can be adapted for use in human subjects.

Animals↗
PubMed2003

Autografting as a risk factor for persisting iron overload in long-term survivors of acute myeloid leukaemia.

We studied the iron status of 32 evaluable adult acute myeloid leukaemia (AML) survivors who were entered into the UK Medical Research Council acute myeloid leukaemia (AML) 10 and 12 trials at our institution between 1988 and 1998. Patients were required to have been independent of all blood products for at least 3 years. As a group, the median first serum ferritin level was 1323 mug/l (NR 19-300 mug/l) at a median of 1321 days from the last transfusion confirming the presence of significant iron overload persisting for some years after completion of all therapy and blood products. There was a general trend for the serum ferritin level to fall with time, but the fall was less pronounced in men and carriers of the C282Y mutation. Recipients of autologous stem cell transplantation (SCT) had a higher median first serum ferritin level (3245 mug/l) than patients who received chemotherapy alone (1148 mug/l) or allogeneic SCT (1334 mug/l) because of increased use of transfused blood. Nine of the 10 recipients of autologous SCT underwent venesection. No evidence of end organ damage was seen in any patient. Serial monitoring of serum ferritin and assessment of the C282Y status may be useful in all long-term AML survivors, especially autograft recipients.

Acute Disease↗
PubMed2005

Cardiac transplantation in patients with iron overload cardiomyopathy.

A review of the published world experience with heart transplantation for iron overload cardiomyopathy (IOC) between 1967 and 2003 as well as review of unpublished cases from the database of the United Network for Organ Sharing since 1992, identified a total of 16 patients (14 men and 2 women). Mean age was 31 years (range, 14-63 years). IOC etiology was hemochromatosis in 11 patients (69%), thalassemia major in 4 (25%), and Diamond-Blackfan anemia in 1 (6%). The 30-day mortality was 12%. Three patients (19%) died within 1 year of the transplant, all of infectious complications. An additional patient died at 7.14 years (unknown cause). The actuarial Kaplan-Meier 1-, 3-, and 5-year survival rates were 81% for all 3 time intervals. The actuarial 10-year survival was 41%.

Adolescent↗
PubMed1982

Early iron overload in beta-thalassaemia major: when to start chelation therapy?

Twenty-eight children with beta-thalassaemia major aged between 11 and 48 months were given intensive transfusions. Serum iron, transferrin saturation, serum ferritin, non-transferrin iron, and subcutaneous desferrioxamine-induced urinary iron excretion were measured. The results showed that even children with a limited number of transfusions had severe iron overload as indicated, in particular, by the raised serum ferritin levels and the high excretion rates after subcutaneous infusion of desferrioxamine. The desferrioxamine test was useful, even in very young children, in assessing response to chelation therapy thus enabling such treatment to be started early to prevent harm from iron overload.

Child, Preschool↗
PubMed1992

Iron overload of the liver by trimethylhexanoylferrocene in rats.

Iron-deficient female Wistar rats were fed a diet, which contained 0.5% trimethylhexanoylferrocene, over a 56-week period. This dietary iron loading resulted in a progressive siderosis and enlargement of the liver with a maximum iron content of 947.0 +/- 148.0 mg (vs. 0.07 +/- 0.04 mg in iron deficiency) and a maximum organ weight of 39.4 +/- 6.6 g (vs. 6.9 +/- 1.4 g in iron-deficient control rats). Up to 43 weeks, whole liver iron rose by increase in iron concentration (max. 28.0 +/- 6.1 mg/g wet weight, w.w.) as well as by enlargement of the organ. Afterwards whole liver iron increased solely by ongoing hepatomegaly. At the commencement of iron loading, stainable iron was almost exclusively stored by hepatocytes equally throughout all areas of the liver lobule. Later, the distribution of iron-loaded hepatocytes became strikingly periportal, and, in addition, Kupffer cells as well as sinus-lining endothelia began to store iron. Animals with a liver iron concentration of more than 10.4 +/- 0.75 mg/g w.w. showed no further increase in ferritin and haemosiderin within hepatocytes. Iron-burdened Kupffer cells/macrophages, however, accumulated permanently, hereby forming intrasinusoidal and portal siderotic nodules and areas. First signs of liver damage such as necrosis of single hepatocytes and mild fibrosis began at a liver iron concentration of 14.7 +/- 1.4 mg/g w.w. With advancement of iron loading, focal necrosis of hepatocytes and iron-burdened macrophages took place, and significant perisinusoidal as well as portal fibrosis developed. Cirrhosis, however, the final stage of impairment in iron overload of the liver in humans, could not be induced in this animal model up to now.

Animals↗
PubMed1987

1,2-Dimethyl-3-hydroxypyrid-4-one, an orally active chelator for treatment of iron overload.

Subcutaneous desferrioxamine, though effective in preventing or reducing iron overload in transfusion-dependent refractory anaemia, is expensive and inconvenient. One potentially cheaper and orally active alternative is 1,2-dimethyl-3-hydroxypyrid-4-one (L1). This drug has been tested in three multiply transfused patients with myelodysplasia. Gelatin capsules were taken at doses ranging from 0.5 g to 3.0 g. Urinary iron excretion increased substantially in all three patients and in the one tested was equal to that achieved with comparable doses of subcutaneous desferrioxamine. The amounts of iron excreted were related to the dose of L1 administered and the iron load of the patients. The urinary excretion of zinc, magnesium, and calcium did not increase, and the drug was well tolerated.

Administration, Oral↗
PubMed2002

ABCB6 (MTABC3) excluded as the causative gene for the growth retardation syndrome with aminoaciduria, cholestasis, iron overload, and lactacidosis.

GRACILE syndrome (growth retardation, aminoaciduria, cholestasis, iron overload, lactacidosis, and early death; OMIM 603358) is a rare metabolic disorder with autosomal recessive mode of inheritance. So far it has been diagnosed only in patients with Finnish ancestors. The GRACILE locus has been positioned to a restricted region of chromosome 2q33-37, but the causative gene remains to be identified. The ABCB6 gene, involved in iron homeostasis, mitochondrial respiratory function, and maintenance of the stability of mitochondrial DNA, has been positioned to this same chromosomal region, and advocated in literature as a highly probable candidate gene for the syndrome on both functional and positional grounds. We carried out sequence and quantitative expression analyses to detect potential disease-associated mutations in the ABCB6 gene. No mutations in the coding region of ABCB6 were found, and the expression level of ABCB6 in patient fibroblasts was found to be comparable to controls. Haplotype analysis of the critical DNA region provided evidence for positional exclusion also. Based on these data, ABCB6 is not the causative gene for GRACILE syndrome.

ATP-Binding Cassette Transporters↗
PubMedDate not supplied

Hemochromatosis gene (HFE) mutations in South East Asia: a potential for iron overload.

Hereditary hemochromatosis (HH) is an autosomal recessive disease caused by mutations in the HFE gene that mainly affects populations of European descent. Recently a novel mutation (IVS5+1 G-->A) has been described in a Vietnamese patient with HH that was not detected in a European control population. We have developed a novel method to screen for this mutation based on restriction enzyme digestion of a PCR product using a modified forward primer. We have screened 314 Vietnamese people from several ethnic groups and 154 people from Thailand for this mutation and have detected two heterozygotes in the Vietnamese subjects (allele frequency 0.003). Analysis of these heterozygotes indicates that the mutation is on the same haplotype as that found in the original proband. Screening for the widely distributed HFE mutation, H63D, gave an allele frequency of 0.049 in the Vietnamese subjects and 0.032 in the subjects from Thailand. This is the first report of H63D allele frequencies in these populations. We suggest that the presence of the IVS5+1 G-->A and H63D mutations should be considered when investigating iron overload in Vietnamese patients and those of mixed origin as co-inheritance of both mutations is likely to be a risk factor for iron overload.

Gene Frequency↗
PubMed1977

Idiopathic hemochromatosis and iron overload in alcoholic liver disease: differentiation by HLA phenotype.

HLA A and B antigens were determined in two groups of patients: 38 patients with idiopathic hemochromatosis (IH) and 22 patients with iron overload accompanying alcoholic liver disease (AH). As previously described, HLA A3 and HLA B14 antigens appeared more frequently in the IH group (76.3 and 28.9%, respectively) than in a control group of 204 subjects (27 and 3.4%). In the AH group the frequency of A3 (22.7%) and B14 (13.6%) was not significantly different from that observed in controls. The frequency of A3 was significantly lower in the AH group than in the IH group (P less than 0.001). On this basis a clear difference appears between the two conditions with iron overload, and genetic analysis of the results rules out the hypothesis that AH would be a heterozygous form of IH exposed by alcohol.

Adult↗
PubMed2003

Constitutive hepcidin expression prevents iron overload in a mouse model of hemochromatosis.

Hereditary hemochromatosis is a prevalent genetic disorder of iron hyperabsorption leading to hyperferremia, tissue iron deposition and complications including cirrhosis, hepatocarcinoma, cardiomyopathy and diabetes. Most individuals affected with hereditary hemochromatosis are homozygous with respect to a missense mutation that disrupts the conformation of HFE, an atypical HLA class I molecule (ref. 1; OMIM 235200). Mice lacking Hfe or producing a C282Y mutant Hfe protein develop hyperferremia and have high hepatic iron levels. In both humans and mice, hereditary hemochromatosis is associated with a paucity of iron in reticuloendothelial cells. It has been suggested that HFE modulates uptake of transferrin-bound iron by undifferentiated intestinal crypt cells, thereby programming the absorptive capacity of enterocytes derived from these cells; however, this model is unproven and controversial. Hepcidin, a peptide hormone (HAMP; OMIM 606464), seems to act in the same regulatory pathway as HFE. Although expression of mouse Hamp is normally greater during iron overload, Hfe-/- mice have inappropriately low expression of Hamp. We crossed Hfe-/- mice with transgenic mice overexpressing Hamp and found that Hamp inhibited the iron accumulation normally observed in the Hfe-/- mice. This argues against the crypt programming model and suggests that failure of Hamp induction contributes to the pathogenesis of hemochromatosis, providing a rationale for the use of HAMP in the treatment of this disease.

Animals↗