Iron accumulation

Another condition involving ceruloplasmin is aceru-loplasminemia. in this genetic disorder, levels of ceruloplasmin are very low and consequently its ferroxidase activity is markedly deficient. This leads to failure of release of iron from cells, and iron accumulates in certain brain cells, hepatocytes, and pancreatic islet cells. Affected individuals show severe neurologic signs and have diabetes mellitus. Use of a chelating agent or administration of plasma or ceruloplasmin concentrate may be beneficial. 

N. von Wiren, V. Romheld, T. Shioiri, and H. Marschner, Competition between micro-organisms and roots of barley and. sorghum for iron accumulated in the root apoplasm. TVeu P7(yw7. /T0 511 (1995). 

Although iron-sulfur proteins are found in various cellular localizations in eukaryotic cells, mitochondria are the major site of Fe-S cluster biosynthesis (Lill et ah, 1999). Deletions in nuclear genes involved in mitochondrial iron-sulfur cluster formation lead to massive accumulation of iron in mitochondria (Chapter 7). For example, deletion of ATM1, a mitochondrial ATPase, which seems to be responsible for the export of Fe-S clusters, leads to respiratory incompetence, excessive iron accumulation and leucine auxotrophy (Kispal et ah, 1999). In Ayfhl cells there is only partial loss of mitochondrial Fe-S enzymes and the cells are not leucine auxotrophs. 

Hemox2 Iron recycling hemox2-/- mice (Dennery et al., 1998) Lung iron accumulation idiopathic pulmonary siderosis (Dearborn, 1997)... 

The progression of human immunodeficiency virus (HIV) towards its more advanced stages is accompanied by increasing body stores of iron. Iron accumulates in macrophages as well as microglia, endothelial cells and myocytes. The iron burden is especially intense in the bone marrow, brain white matter, muscle and liver. Such excesses of iron will enhance oxidative stress, impair several already compromised immune defence mechanisms and directly promote the growth of microbes (Boelaert et ah, 1996). 

The first data about nonbarrier iron accumulation by external layers of tree trunk bark were received by us on Ermakovskii fluorite-beryllium deposit in Zabaikalye. Detailed research of chemical element (CE) distribution in cross-sections of trees trunks and in their other parts and species of plants were conducted here for... 

Frataxin is the protein involved in Friedreich s ataxia, the most common ataxia found in man, associated with massive iron accumulation in mitochondria. 

Alterations in brain iron metabolism have been reported, resulting in increased iron accumulation in Huntington s disease. This was particularly the case in basal ganglia from patients with HD compared to normal controls. In studies in embryonic stem cells, huntingtin was found to be iron-regulated, essential for the function of normal nuclear and perinuclear organelles and to be involved in the regulation of iron homeostasis. 

The second problem is the possible presence of deoxyhemoglobin in the tissues. Indeed, deoxyhemoglobin could contribute to the transverse relaxation but through a non-linear transverse rate enhancement since for this protein l/T 2 increases quadratically with the magnetic field. Such an effect has only been noticed for blood (51). As a conclusion, the present state-of-the-art allows to claim that MRI provides a qualitative indication and a quantitative estimation of iron accumulation, but is unable to approach the accuracy of the chemical determination of iron content. 

Avunduk, and L. Kurnaz. Cadmium and iron accumulation in rat lens after cigarette smoke exposure and the effect of vitamin E (alpha-tocopherol) treatment. Curr Eye Res 1999 18(6) 403-407. 

The iron sulfide (or pyrophorric iron) accumulates as a blackish-gray deposit inside the tubes. 

There is increasing evidence that iron is involved in several neurodegenera-tive diseases. Conditions such as neuroferritinopathy and Friedreich ataxia are associated with mutations in genes that encode proteins that are involved in iron metabolism. As the brain ages, iron accumulates in regions that are affected in AD and PD. High concentrations of reactive iron can increase... 

Iron-containing compounds in biological and clinical samples have been studied by separating them on chromatographic columns that were coupled to inductively coupled plasma mass spectrometers. Four iron-containing proteins, namely ferritin, haemoglobin, myoglobin and cytochrome-c were separated on a gel permeation column (Takatera and Watanabe, 1991). The absolute detection limits were 0.01-1 mg for the four proteins when 10 ml injections of samples were analysed. In other research, excess iron accumulations in human and animal... 

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