Iron overload

Iancu, Theodore C.

doi:10.1016/0098-2997(83)90004-3

Cited by 58 publications

(34 citation statements)

References 140 publications

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“…Three of the patients' livers (1, 2, and 3) showed evidence of iron overloading, with increased haemosiderin and ferritin deposits in hepatocytes in a pattern typical for parenchymal iron overload (Iancu, 1983). Two of the patients (2 and 3) had been extensively haemodialysed, a procedure known to produce iron overloading (Ali et al, 1980), and patients 1, 2 and 3 had received blood transfusions previously.…”

Section: Discussionmentioning

confidence: 98%

Primary hyperoxaluria type I: Ultrastructural observations in liver biopsies

Iancu

Danpure

1987

J of Inher Metab Disea

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The liver ultrastructure of four patients with the peroxisomal disease primary hyperoxaluria type I has been investigated. In all cases, peroxisomes of normal appearance were present in the parenchymal cells, except that they were somewhat reduced in number and size. In all patients, conspicuous lipofuscin was present, presumably resulting from the various metabolic disturbances to which the livers were subjected during the course of their disease. Considerable hepatocyte iron overloading was found in the three patients who had been hemodialyzed and/or had blood transfusions. Whether the relatively mild peroxisomal abnormalities (as compared to other peroxisomal diseases, such as Zellweger's syndrome) found in these hyperoxaluric patients are related directly to the peroxisomal deficiency of alanine:glyoxylate aminotransferase, or whether they are a secondary phenomenon, resulting from the consequent metabolic disturbance, remains to be elucidated.

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Section: Discussionmentioning

confidence: 98%

Primary hyperoxaluria type I: Ultrastructural observations in liver biopsies

Iancu

Danpure

1987

J of Inher Metab Disea

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“…not as tightly regulated as it is in mammals. However, although some authors favour the hypothesis that dietary overload is responsible for the development of haemosiderosis in many avian species (Kincaid & Stoskopf, 1987) the distribution of iron in the liver is not the same as that seen in human dietary overload (Iancu, 1982;Iancu et al, 1987) or in the early stages of primary haemochromatosis (Powell et al, 1980). There has not been any conclusive evidence that the presence of stainable iron in the liver of birds has any clinical significance although it has been linked to the presence of concurrent infectious (Lowenstine & Petrak, 1980) and neoplastic diseases (Hill et al, 1986).…”

Section: Introductionmentioning

confidence: 92%

A quantitative assessment of haemosiderosis in wild and captive birds using image analysis

1995

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An experimental model of haemosiderosis, using the chicken, was developed to examine the distribution of iron in the liver following an injection of iron dextran and to allow calibration of image analysis readings. Image analysis was used as a tool to quantify the stainable iron present in hepatic tissue obtained from wild and captive birds presented for necropsy. A retrospective study of 180 necropsy cases, representing 40 different species of bird, is described. Statistical evaluation of the amount and distribution of stainable iron in the liver tissue of birds from different taxonomic orders indicated that the concentration of iron measured in liver tissue was significantly different in different species of bird. The results of the study showed that hepatic haemosiderosis is a common histological finding in most avian species examined. Although not necessarily associated with overt liver disease, it is often associated with concurrent malignant and infectious diseases. The presence of excess stainable iron in the liver is probably a reflection of an altered iron metabolism associated with increased turnover of tissue iron. This alteration may occur following starvation or trauma.

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“…Haemosiderin is not, however, necessarily the end product as massive quantities of iron oxyhydroxide (haemosiderin) from these secondary lysosomes, can accumulate to form cytoplasmic organelles known as siderosomes (Richter, 1978). The haemosiderin-containing siderosomes can thus be regarded as the end-product of secondary lysosome action in which the wall of the original secondary lysosome now encapsulates the digested ferritin iron cores (Harrison & Arosio, 1996;Wixom et al, 1980)-although clusters of electrondense material without membranes or only partially enclosed membranes can also occur (Deiss, 1983;Harrison & Arosio, 1996;Iancu, 1982). Within siderosomes, ferritin can be identified as individual particles, in clusters, in paracrystalline hexagonal arrays, or forming circular arrangements (Iancu, 1992).…”

Section: The Formation Of Haemosiderin From Ferritinmentioning

confidence: 99%

“…However, as long as the ferritin cluster is not enclosed by a membrane, degradation of these ferritin clusters can result in the release of iron in times of iron shortage. Various studies indicated that the formation of large iron-rich ferritin particles, as a result of an increase in intracellular iron, results in the protection of ferritin molecules against degradation (Iancu, 1982;Truty et al, 2001;Worwood, 1982) and that iron-depleted ferritin is easily degraded Wixom et al, 1980). The 20S proteasome enzymatic system is responsible for the degradation of damaged intracellular proteins and can recognize specifically, and degrade, oxidized proteins (Mehlhase et al, 2005;Rudeck et al, 2000).…”

Section: The Degradation Of Ferritinmentioning

confidence: 99%

Ferritin and ferritin isoforms I: Structure–function relationships, synthesis, degradation and secretion

Koorts

Viljoen

2007

Archives of Physiology and Biochemistry

134

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Ferritin is the intracellular protein responsible for the sequestration, storage and release of iron. Ferritin can accumulate up to 4500 iron atoms as a ferrihydrite mineral in a protein shell and releases these iron atoms when there is an increase in the cell's need for bioavailable iron. The ferritin protein shell consists of 24 protein subunits of two types, the H-subunit and the L-subunit. These ferritin subunits perform different functions in the mineralization process of iron. The ferritin protein shell can exist as various combinations of these two subunit types, giving rise to heteropolymers or isoferritins. Isoferritins are functionally distinct and characteristic populations of isoferritins are found depending on the type of cell, the proliferation status of the cell and the presence of disease. The synthesis of ferritin is regulated both transcriptionally and translationally. Translation of ferritin subunit mRNA is increased or decreased, depending on the labile iron pool and is controlled by an ironresponsive element present in the 5'-untranslated region of the ferritin subunit mRNA. The transcription of the genes for the ferritin subunits is controlled by hormones and cytokines, which can result in a change in the pool of translatable mRNA. The levels of intracellular ferritin are determined by the balance between synthesis and degradation. Degradation of ferritin in the cytosol results in complete release of iron, while degradation in secondary lysosomes results in the formation of haemosiderin and protection against iron toxicity. The majority of ferritin is found in the cytosol. However, ferritin with slightly different properties can also be found in organelles such as nuclei and mitochondria. Most of the ferritin produced intracellularly is harnessed for the regulation of iron bioavailability; however, some of the ferritin is secreted and internalized by other cells. In addition to the regulation of iron bioavailability ferritin may contribute to the control of myelopoiesis and immunological responses.

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Iron overload

Cited by 58 publications

References 140 publications

Primary hyperoxaluria type I: Ultrastructural observations in liver biopsies

Primary hyperoxaluria type I: Ultrastructural observations in liver biopsies

A quantitative assessment of haemosiderosis in wild and captive birds using image analysis

Ferritin and ferritin isoforms I: Structure–function relationships, synthesis, degradation and secretion

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