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PubMed1993

Postmortem findings and prenatal diagnosis of Zellweger syndrome. Case report.

The postmortem findings of siderosis, renal cortical cysts, pachygyria, cortical heterotopia of the brain and cerebellar hypoplasia in a seven-week-old infant with craniofacial dysmorphism and hypotonia prompted the diagnosis of Zellweger syndrome. This was confirmed by analysis of very-long-chain fatty acids in blood spots from filter paper, collected in the neonatal period, and allowed first trimester diagnosis in the subsequent pregnancies.

Autopsy↗

PubMed1998

Pathophysiology of iron overload.

In thalassemia, iron overload is the joint outcome of excessive iron absorption and transfusional siderosis. While iron absorption is limited by a physiologic ceiling of about 3 mg/d, plasma iron turnover in thalassemia may be 10 to 15 times normal, caused by the wasteful, ineffective erythropoiesis of an enormously expanded erythroid marrow. This outpouring of catabolic iron exceeds the iron-binding capacity of transferrin and appears in plasma as non-transferrin-plasma iron (NTPI). The toxicity of NTPI is much higher than of transferrin-iron as judged by its ability to promote hydroxyl radical formation resulting in peroxidative damage to membrane lipids and proteins. In the heart, this results in impaired function of the mitochrondrial respiratory chain and abnormal energy metabolism manifested clinically in fatal hemosiderotic cardiomyopathy. Ascorbate increases the efficacy of iron chelators by expanding the intracellular chelatable iron pool, but, at suboptimal concentrations is a pro-oxidant, enhancing the catalytic effect of iron in free radical formation. NTPI is removed by i.v. DFO in a biphasic manner and reappears rapidly upon cessation of DFO, lending support to the continuous, rather than intermittent, use of chelators. Unlike DFO and other hexadentate chelators, bidentate chelators such as L1 may produce incomplete intermediate iron complexes at suboptimal drug concentrations.

Animals↗

PubMed1980

Serum ferritin, liver iron stores, and liver histology in children with thalassaemia.

Serum ferritin, liver iron stores, and liver histology were studied in 38 children with thalassaemia major who were being treated by regular blood transfusions. There was no correlation between serum ferritin levels and either the number of transfusions or the amount of iron deposited in the liver. However, for a given level of iron stores, ferritin levels were higher in patients with chronic hepatitis (including chronic aggressive and chronic persistent forms) than in those with hepatic siderosis only. We conclude that serum ferritin reflects tissue iron deposits in regularly transfused thalassaemic patients, only in the absence of hepatitis.

Blood Transfusion↗

PubMed1968

Effects of iron overload on ascorbic acid metabolism.

Studies of the ascorbic acid status in two subjects with idiopathic haemochromatosis and in 12 with transfusional siderosis showed that all had decreased levels of white cell ascorbic acid. The urinary excretion of ascorbic acid was also diminished in those subjects in whom such measurements were made. The administration of ascorbic acid was followed by only a small rise in the urinary ascorbic acid output, while the oxalic acid levels (measured in two subjects) showed a significant rise. These findings resemble those described in siderotic Bantu, and support the thesis that increased iron stores lead to irreversible oxidation of some of the available ascorbic acid.

Adolescent↗

PubMed1969

Differential ferrioxamine test in haemochromatosis and liver diseases.

The effect of desferrioxamine is examined in more than 100 patients with liver disease, including haemochromatosis, using the differential ferrioxamine test. The procedure gives a reasonably accurate estimate of the size of the iron stores, as determined by multiple venesection, in patients with idiopathic haemochromatosis. Since desferrioxamine is not specific for storage iron, unequivocally abnormal results are not obtained unless the iron load exceeds about 2.3 g. In other forms of liver disease the effect of desferrioxamine is generally increased compared with that in controls. The results show no correlation with the serum iron level or the degree of hepatic siderosis. High values are usual in the presence of jaundice and overlap the range found in untreated haemochromatosis, adding to other evidence that desferrioxamine can derive iron from a hyperchelatable source unrelated to the stores. It is concluded that in liver diseases other than haemochromatosis the results of the test do not reliably reflect body storage iron content.

Adult↗

PubMed1970

Measurement of iron stores in cirrhosis using diethylenetriamine penta-acetic acid.

The chelating agent diethylenetriamine penta-acetic acid was used to measure iron stores in 83 patients with chronic liver disease. Iron chelation was normal in patients with chronic cholestasis. Chelation was increased above the control range in 14 out of 26 patients with alcoholic cirrhosis, in nine out of 28 patients with non-alcoholic cirrhosis, and in 11 out of 15 cirrhotics with a portacaval anastomosis. Iron stores in excess of 1.5 g were predicted from the results in 24 subjects; however, in only three were the values in the range found in propositi with untreated idiopathic haemochromatosis. Increased chelation did not correlate with hepatocellular impairment per se but was associated in 18 cases with surgical or large spontaneous portal systemic shunts. Exogenous factors for excess iron were present in three cases with alcoholic cirrhosis and portal systemic collaterals in one, but no special factor apart from alcoholism was apparent in the remainder. The correlation between chelatable iron and stainable liver iron content was not close and was better in haemochromatosis than in other forms of cirrhosis; in some cases considerable siderosis was present with normal or only slightly increased chelation values.

Adult↗

PubMed1971

Experimental hepatic cirrhosis in dogs caused by chronic massive iron overload.

Starting in October 1966, 19 dogs have been subjected to massive parenteral iron loading using intravenous iron-dextran and intramuscular iron-sorbitol. Although 13 animals died, in many cases the deaths were attributable to fighting. The large doses of iron employed (up to 5.8 g/kg) were well tolerated by the surviving animals, and after 35 to 47 months five of the six survivors have developed hepatic cirrhosis with massive siderosis; the dog which has not yet developed cirrhosis received the smallest iron load. The liver pathology in many ways resembles that of human haemochromatosis, and may provide an experimental model for the study of chronic iron-induced liver injury.

Animals↗

PubMed1999

Spur cell anaemia and hepatic iron stores in patients with alcoholic liver disease undergoing orthotopic liver transplantation.

BACKGROUND: Following orthotopic liver transplantation (OLT) histological examination of explant livers from patients with alcoholic liver disease (ALD) sometimes shows extensive iron deposits in a distribution suggestive of homozygous haemochromatosis. AIMS: To use haemochromatosis gene (HFE) assays to distinguish between ALD with notable siderosis and hereditary haemochromatosis. To evaluate the possible influence of spur cell haemolytic anaemia on hepatic iron loading. PATIENTS: Thirty seven patients with ALD were abstinent for at least six months prior to OLT. Twenty three patients had transferrin saturations greater than 55%, 16 also had increased serum ferritin (>350 micrograms/l). Eight of 37 (22%) explant livers had grade 3 or 4 hepatic iron deposition, predominantly in hepatocytes. Of these, four had a hepatic iron index greater than 1. 9 and most seemed to have spur cell haemolytic anaemia. METHODS: Mutation analysis for C282Y and H63D mutations was performed on DNA extracts from peripheral blood or explant liver. Spur cell haemolytic anaemia was diagnosed when the haemoglobin was 105 g/l in the presence of notable acanthocytosis. RESULTS: None of the eight patients with grade 3 or 4 hepatic iron had evidence of the C282Y mutation. Two of the eight were heterozygous for H63D. None of the remaining 28 patients tested showed homozygous HFE mutations. Spur cell anaemia was present in six of the eight patients with heavy iron deposition and only one of the remaining patients. CONCLUSIONS: The HFE mutation was not present in these patients with advanced ALD and heavy iron loading. Spur cell haemolytic anaemia provides an alternative potential mechanism for the heavy iron loading.

Adult↗

PubMed1968

Ultrastructural study of the liver in hepatic prophyria.

In intermittent acute porphyria there are no specific alterations in the ultrastructure of the liver. In contrast, the constant characteristic of porphyria cutanea tarda is siderosis of the hepatocytes and Kupffer cells. Therefore, between the two types of hepatic porphyria there are no similar ultrastructural lesions. It is still doubtful whether the presence of hepatosiderosis in porphyria cutanea tarda is connected with the hepatopathy or is secondary to an alteration in the porphyrinic metabolism. The role played by lysosomes is discussed.

Liver↗

PubMed1974

Serum ferritin in children with thalassaemia regularly transfused.

A controlled trial of continuous chelation therapy in regularly transfused children with homozygous beta-thalassaemia has been in progress at the Hospital for Sick Children since April 1966. In the sixth and seventh years of the trial the effect of this treatment on iron overload has been assessed by estimating serum ferritin levels and liver iron concentrations in both chelator-treated and control groups. When compared with non-chelated controls, results of both these estimations were invariably lower in the chelated group. However, all the results in both groups were very high, and fell within the ranges observed in untreated idiopathic haemochromatosis. A close correlation was found between serum ferritin levels and liver iron concentrations in these children, indicating that serum ferritin is a valuable alternative to liver iron concentration in the assessment of visceral iron overload, even when massive tissue siderosis is present.

Blood Transfusion↗

PubMed2000

Diminished injury in hypotransferrinemic mice after exposure to a metal-rich particle.

Using the hypotransferrinemic (Hp) mouse model, we studied the effect of altered iron homeostasis on the defense of the lung against a catalytically active metal. The homozygotic (hpx/hpx) Hp mice had greatly diminished concentrations of both serum and lavage fluid transferrin relative to wild-type mice and heterozygotes. Fifty micrograms of a particle containing abundant concentrations of metals (a residual oil fly ash) was instilled into wild-type mice and heterozygotic and homozygotic Hp animals. There was an oxidative stress associated with particle exposure as manifested by decreased lavage fluid concentrations of ascorbate. However, rather than an increase in lung injury, diminished transferrin concentrations in homozygotic Hp mice were associated with decreased indexes of damage, including concentrations of relevant cytokines, inflammatory cell influx, lavage fluid protein, and lavage fluid lactate dehydrogenase. Comparable to other organs in the homozygotic Hp mouse, siderosis of the lung was evident, with elevated concentrations of lavage fluid and tissue iron. Consequent to these increased concentrations of iron, proteins to store and transport iron, ferritin, and lactoferrin, respectively, were increased when assayed by immunoprecipitation and immunohistochemistry. We conclude that the lack of transferrin in Hp mice did not predispose the animals to lung injury after exposure to a particle abundant in metals. Rather, these mice demonstrated a diminished injury that was associated with an increase in the metal storage and transport proteins.

Air Pollution↗

PubMed1999

Storage of iron in bone marrow plasma cells. Ultrastructural characterization, mobilization, and diagnostic significance.

The physiological site of iron storage in the human bone marrow is the macrophage (orthotopic iron store). Iron-storing plasma cells, as bone marrow indicators of iron overload, and/or chronic alcoholism represent a pathological (heterotopic) iron store. They were demonstrated by light and electron microscopy in 23 iron-overloaded patients: transfusional siderosis (n = 8), genetic haemochromatosis (GH; n = 11), iron-loading anaemias (n = 4) and in patients with bone marrow impairment due to chronic alcoholism (n = 6). The pattern of iron storage in bone marrow plasma cells was monitored during iron loading in patients receiving continuous transfusional therapy (n = 7) and also upon reversal of iron overload by repeated phlebotomies in GH (n = 9) and in iron-loading anaemias (n = 4). The first ultrastructural evidence of iron storage in plasma cells was the appearance of free ferritin molecules in the cytosol, thus indicating endogenous ferritin synthesis. Accumulation of iron proceeded with the additional formation of ferritin- and haemosiderin-containing lysosomes (siderosomes) in these cells. Lysosomal ferritin partially showed a paracrystalline array. The siderosomes originated from autophagocytosis of cytoplasmic areas containing free ferritin molecules. In addition, the formation of ferritin-containing vesicles in the proximity of the Golgi apparatus was observed. The heterotopic iron store of bone marrow plasma cells was less readily mobilizable by blood-letting than the orthotopic store of macrophages.

Adult↗

PubMed1984

Experimental investigations on the penetration into the eyeball of iron administered intraorbitally.

In order to elucidate the still controversial question whether iron foreign bodies located in the orbit can produce siderosis bulbi, the authors studied the concentration of iron in the aqueous of rabbits in which the metal was placed outside the eyeball, close to the exposed sclera. It was found that iron penetrates into the eye, its concentration in the aqueous increasing with the lapse of time. It was also found that this concentration was distinctly higher in animals which had received higher amounts of iron.

Animals↗

PubMed1988

Electroretinographic and visual-evoked potential abnormalities in patients with beta-thalassemia major.

Various ocular abnormalities have been reported in patients with thalassemia, and have been, for the most part, attributed to the toxic effects of high-dose desferrioxamine (DFO). We have performed an electroretinographic and visual-evoked potential (VEP) study in 31 thalassemic patients who had never received high doses of DFO. The abnormalities found were very similar to those reported in early siderosis bulbi and included a b1-wave of significantly higher amplitude at 1 min and at the alpha point. VEPs showed a N1-P1 amplitude significantly greater than in controls. These findings, which were more marked in older patients, point to an important causative role of iron in their genesis.

Adolescent↗

PubMed1987

Determination of iron in cardiac and liver tissues by plasma emission spectroscopy.

A simple plasma emission spectroscopic method for the determination of iron in liver and cardiac tissue is described. Using this technique, iron was extracted quantitatively from liver tissue of mass 14.2 to 65.4 mg wet weight, and heart tissue of mass 5.9 to 27.4 mg wet weight. Iron added to liver as aqueous ferric nitrate was recovered in the range 93 to 108%. Reference ranges for liver and myocardial iron on post mortem tissue gave respectively mean values of 0.841 mg/g dry weight (Range 0.310 to 1.600, n = 37) and 0.340 mg/g dry weight (Range 0.290 to 0.470, n = 8). Data on patients with haemochromatosis and transfusion siderosis are also presented.

Aged↗

PubMed2000

T2 relaxation rate as an index of pituitary iron overload in patients with beta-thalassemia major.

OBJECTIVE: In transfusion-dependent ss-thalassemia major, increased iron deposition in the pituitary gland has a cytotoxic effect, leading mainly to hypogonadotropic hypogonadism. Early detection and quantification of iron in the pituitary gland are of particular importance for successful treatment. The purpose of this study was to evaluate the T2 relaxation rate (1/T2) as a marker of pituitary siderosis. SUBJECTS AND METHODS: In 29 patients with ss-thalassemia major and 40 controls, we assessed the 1/T2 of the pituitary gland in a 1.5-T MR unit, using a multiecho spin-echo sequence. In all patients, an extensive endocrine evaluation was performed, including measurements of spontaneous and stimulated levels of gonadotropins, thyroid hormones, growth hormone, insulinlike growth factor, and adrenal hormones. RESULTS: A positive correlation was found between the 1/T2 and the serum ferritin level (r = 0.73, p < 0.001). The 1/T2 was higher in patients (mean, 0.020 msec(-1); SD, 0.006) compared with that of controls (mean, 0.011 msec(-1); SD, 0.001; p < 0.001). The 1/T2 was higher in patients with hypogonadotropic hypogonadism (mean, 0.024 msec(-1); SD, 0.006) in comparison with that of patients without any pituitary dysfunction (mean, 0.017 msec(-1); SD, 0.004; p < 0.05). CONCLUSION: The T2 relaxation rate could be used as an index of pituitary iron overload, and it might be of value to monitor treatment with deferoxamine in patients with ss-thalassemia major.

Adult↗

PubMed1975

Rheumatic disorders in the South African Negro. Part III. Idiopathic necrosis of the femoral head.

Idiopathic necrosis of the femoral head, with progressive articular destruction, is a well-recognised disorder in the South African Negro. Twenty-nine cases were studied in detail. In 17 there was evidence of associated iron overload, but it is unlikely that this contributed directly to the occurence of osteonecrosis. The syndrome of siderosis, scurvy and osteoporosis in Johannesburg Blacks is attributed to the ingestion of large quantities of iron in home-brewed beer. Often the beer is mixed with much more potent liquor and it is postulated that this, rather than the iron overload, is the cause of 'idiopathic' femoral head necrosis.

Adult↗

PubMedDate not supplied

Tired blood and rusty livers.

Iron deficiency is one of the most serious nutritional problems confronting the United States and the world today. An understanding of the mechanisms operative in the control of uptake and utilization of iron is essential to develop suitable prophylactic and therapeutic strategies. Iron excess can also be a serious health hazard. Studies on Bantu siderosis, hemochromatosis and other overload pathologies also provide insight into the intake and storage of this metal. Several models for iron transport across the mucosal membrane are developed. The most satisfactory seems to involve chelation of the iron to provide solubility diffusion passively across the gut membrane, and equilibrium binding to various storage sites within the tissue. Both ferric and ferrous forms are available. The solution chemistry of iron governs its biological behavior. Low-molecular-weight compounds present in normal dietary foodstuffs, as well as those prepared synthetically, can enhance the uptake of oral iron. Suitable application of complexes of iron with fructose, nitrilotriacetate, citrate and other molecules should be efficacious in the treatment of iron deficiency anemia. Potential dangers of food fortification with iron are acknowledged, and application of immunoassay techniques for measuring circulating ferritin suggest it as a rapid and inexpensive monitor for overload.

Alcoholism↗