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Iron Deposits (iron + deposit)

Distribution by Scientific Domains

Medical Sciences	61%

Selected Abstracts

40Ar- 39Ar Dating of Albite and Phlogopite from Porphyry Iron Deposits in the Ningwu Basin in East-Central China and Its Significance

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2004
YU Jinjie
Abstract,40Ar- 39Ar dating of albite from the Meishan and Taocun iron deposits yields plateau ages of 122.90±0.16 Ma and 124.89±0.30 Ma, and isochron ages of 122.60±0.16 Ma and 124.90±0.29 Ma, respectively. Phlogopite from the Zhongshan-Gushan ore field has a plateau age of 126.7±0.17 Ma and an isochron age of 127.21±1.63 Ma. Analysis of regional geodynamic evolution of the middle-lower Yangtze River region suggests that the porphyry iron deposits were formed as a result of large-scale lithosphere delamination and strong sinistral strike-slip movement of the Tancheng-Lujiang fault zone. The copper, molybdenum and gold deposit system in the middle-lower Yangtze River region was formed during the stress transition period of the eastern China continent. [source]

Phototrophs in high iron microbial mats: microstructure of mats in iron-depositing hot springs

FEMS MICROBIOLOGY ECOLOGY, Issue 3 2000
Beverly K Pierson
Abstract Chocolate Pots Hot Springs in Yellowstone National Park are high in ferrous iron, silica and bicarbonate. The springs are contributing to the active development of an iron formation. The microstructure of photosynthetic microbial mats in these springs was studied with conventional optical microscopy, confocal laser scanning microscopy and transmission electron microscopy. The dominant mats at the highest temperatures (48,54°C) were composed of Synechococcus and Chloroflexus or Pseudanabaena and Mastigocladus. At lower temperatures (36,45°C), a narrow Oscillatoria dominated olive green cyanobacterial mats covering most of the iron deposit. Vertically oriented cyanobacterial filaments were abundant in the top 0.5 mm of the mats. Mineral deposits accumulated beneath this surface layer. The filamentous microstructure and gliding motility may contribute to binding the iron minerals. These activities and heavy mineral encrustation of cyanobacteria may contribute to the growth of the iron deposit. Chocolate Pots Hot Springs provide a model for studying the potential role of photosynthetic prokaryotes in the origin of Precambrian iron formations. [source]

Influence of Helicobacter pylori infection on iron accumulation in hepatitis C

LIVER INTERNATIONAL, Issue 7 2006
Yoshio Sumida
Abstract: Goal: Iron may play a role in the pathogenesis of chronic hepatitis C. Helicobacter pylori (Hp) infection was recently associated with iron-deficiency anemia. We examined the influence of Hp infection on hepatic iron accumulation in hepatitis C. Methods: Ninety-five hepatitis C virus (HCV)-RNA-positive patients, including 60 chronic hepatitis, 17 cirrhosis and 18 hepatocellular carcinoma as well as 95 age- and sex-matched normal subjects without HCV infection as control, were studied. Liver biopsies were also obtained from 44 HCV-infected patients. Serum Hp antibodies were measured by an enzyme-linked immunosorbent assay and clinical data, including iron parameters and histological findings, were compared between Hp-positive and -negative HCV-infected patients. Results: The percentage of serum Hp antibodies was lower in HCV-infected patients than in controls (52/95 (54.7%) vs. 68/95 (71.6%); P<0.05). HCV-infected patients had higher serum ferritin levels than controls (120 [2.8,1700] vs. 58 [2.2,420] ng/ml; P<0.0001). In HCV-infected patients, the serum ferritin levels (medians and [ranges]) in Hp-positive patients were significantly lower than those of Hp-negative patients (99 [8.5,770] vs. 150 [2.8,1700] ng/ml; P<0.05). The grades of hepatic iron deposit in Hp-positive patients were significantly lower than those in Hp-negative patients (P<0.01). Conclusions: Hp infection may at least partly affect hepatic iron accumulation in HCV-related liver diseases. [source]

Preferential patterns of myocardial iron overload by multislice multiecho T*2 CMR in thalassemia major patients

MAGNETIC RESONANCE IN MEDICINE, Issue 1 2010
Antonella Meloni
Abstract T*2 multislice multiecho cardiac MR allows quantification of the segmental distribution of myocardial iron overload. This study aimed to determine if there were preferential patterns of myocardial iron overload in thalassemia major. Five hundred twenty-three thalassemia major patients underwent cardiac MR. Three short-axis views of the left ventricle were acquired and analyzed using a 16-segment standardized model. The T*2 value on each segment was calculated, as well as the global value. Four main circumferential regions (anterior, septal, inferior, and lateral) were defined. Significant segmental variability was found in the 229 patients with significant myocardial iron overload (global T*2 <26 ms), subsequently divided into two groups: severe (global T*2 <10 ms) and mild to moderate (global T*2 between 10 and 26 ms) myocardial iron overload. A preferential pattern of iron store in anterior and inferior regions was detected in both groups. This pattern was preserved among the slices. The pattern could not be explained by additive susceptibility artifacts, negligible in heavily iron-loaded patients. A significantly higher T*2 value in the basal slice was found in patients with severe iron overload. In conclusion, a segmental T*2 cardiac MR approach could identify early iron deposit, useful for tailoring chelation therapy and preventing myocardial dysfunction in the clinical setting. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc. [source]

Serum Iron and Matrix Metalloproteinase-9 Variations in Limbs Affected by Chronic Venous Disease and Venous Leg Ulcers

DERMATOLOGIC SURGERY, Issue 6 2005
Paolo Zamboni MD
Background. Severe chronic venous disease (CVD) is characterized by both dermal hemosiderin accumulation and matrix metalloproteinase (MMP) hyperactivation. The iron-driven pathway is one of the recognized mechanisms of MMP hyperactivation. Objective. To investigate the potential consequences of leg hemosiderin deposits on both iron metabolism and activation of MMPs. Methods. We contemporaneously assessed the following in the serum of the arm and ankle veins of 30 patients (C4,6) with CVD and 14 normal subjects: ferritin, transferrin, iron, percentage of transferrin iron binding capacity (%TIBC), and MMP-9. Optical microscopy examinations with Perls' staining of chronic wounds were also performed. Results. Histology consistently revealed iron deposits. Serum ferritin, iron, and %TIBC were significantly increased in the legs affected by severe CVD compared with the arm of the same subjects or the controls. In addition, iron and %TIBC were significantly elevated in the legs of ulcer patients. The rate of activation of MMP-9 was significantly elevated in CVD. Conclusions. The increased iron deposition in legs affected by CVD seems to be more instable in ulcer patients, leading to iron release in the serum of the affected leg. Our data suggest the iron-driven pathway as a further mechanism for MMP hyperexpression leading to tissue lesion. [source]

An experimental study on the transformer coil leakage current

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2006
Mohamed A. A. Wahab
This paper is concerned with the transformer coil dc leakage current under different conditions. These conditions include in-air, and in-oil leakage, currents with or without artificial coil deposits. In-oil leakage, currents are investigated when the coil is immersed in new or used transformer oil at different temperatures. The results showed that the leakage current increases with the increase in the applied voltage and oil temperatures. The rate of increase in leakage current with temperature depends on the transformer oil and coil conditions. The in-oil leakage currents are higher than those obtained in air. The leakage currents measured in used oil are higher than those resulted in new oil. Copper deposits cause higher values of leakage current than iron deposits for the same medium, applied voltage and temperature. Deposits increase the leakage current for different coil surrounding media. A linear model for the leakage current as a function of the applied voltage under different conditions has been found and its validity has been justified by statistical consideration. The parameters of this model account for various experimental conditions. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Haemopexin affects iron distribution and ferritin expression in mouse brain

JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 10 2009
Noemi Morello
Abstract Haemopexin (Hx) is an acute phase plasma glycoprotein, mainly produced by the liver and released into plasma where it binds heme with high affinity and delivers it to the liver. This system provides protection against free heme-mediated oxidative stress, limits access by pathogens to heme and contributes to iron homeostasis by recycling heme iron. Hx protein has been found in the sciatic nerve, skeletal muscle, retina, brain and cerebrospinal fluid (CSF). Recently, a comparative proteomic analysis has shown an increase of Hx in CSF from patients with Alzheimer's disease, thus suggesting its involvement in heme detoxification in brain. Here, we report that Hx is synthesised in brain by the ventricular ependymal cells. To verify whether Hx is involved in heme scavenging in brain, and consequently, in the control of iron level, iron deposits and ferritin expression were analysed in cerebral regions known for iron accumulation. We show a twofold increase in the number of iron-loaded oligodendrocytes in the basal ganglia and thalamus of Hx-null mice compared to wild-type controls. Interestingly, there was no increase in H- and L-ferritin expression in these regions. This condition is common to several human neurological disorders such as Alzheimer's disease and Parkinson's disease in which iron loading is not associated with an adequate increase in ferritin expression. However, a strong reduction in the number of ferritin-positive cells was observed in the cerebral cortex of Hx-null animals. Consistent with increased iron deposits and inadequate ferritin expression, malondialdehyde level and Cu,Zn superoxide dismutase-1 expression were higher in the brain of Hx-null mice than in that of wild-type controls. These data demonstrate that Hx plays an important role in controlling iron distribution within brain, thus suggesting its involvement in iron-related neurodegenerative diseases. [source]

Serum amino-terminal propeptide of type III procollagen and 7S domain of type IV collagen correlate with hepatic iron concentration in patients with chronic hepatitis C following ,-interferon therapy

JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2 2001
Ichiro Shimizu
Abstract Background: It has been reported that chronic infection with hepatitis C virus is associated with excess iron deposits in the liver of subjects who are neither alcoholics nor recipients of blood transfusions. However, little is known about the relationship between hepatic iron concentration (HIC) and the serum levels of hepatic fibrogenesis markers, which were caused by interferon therapy for chronic hepatitis C. Therefore, changes in the serum amino-terminal propeptide of type III procollagen (P-III-P) and the 7S domain of type IV collagen (7S-IV) in 16 patients treated with ,-interferon (IFN-,) were studied, and their HIC and histological assessment evaluated. Hepatic iron concentrations were measured by using liver biopsy specimens obtained before and 6 months after the cessation of treatment. Methods and Results: Eight subjects (50%) who had normal alanine transaminase levels at 6 months after therapy showed significantly lowered HIC, and attenuated hepatic iron staining with decreased serum levels of P-III-P and 7S-IV compared to the remaining subjects. The HIC was significantly correlated with the serum levels of P-III-P and 7S-IV in all subjects. Conclusions: These findings suggest that IFN-, treatment may decrease stimuli for fibrogenesis, at least in part, by reducing the hepatic iron deposition in patients with chronic hepatitis C. [source]

Successful correction of murine sickle cell disease with reduced stem cell requirements reinforced by fractionated marrow infusions

BRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2010
Hady Felfly
Summary Minimal criteria requirements of stem cell replacement, conditioning regimen and modalities of infusion essential for cure of sickle cell disease (SCD) by bone marrow(BM)/stem cell transplantation or gene therapy must be established prior to clinical trials. The threshold of normal BM/stem cells for therapeutic correction of this red blood cell disorder was evaluated in the SAD murine SCD model from peripheral donor white blood cells. From 11 groups of stable chimeric SAD mice (5,92%) analyzed over ,2 years, mice with ,16% normal donor stem cells showed improvement of haematological and erythroid responses. Mice in the 26% chimeric group and above demonstrated substantial amelioration of organ pathologies with generalized decreased iron deposits, fibrosis and reached normal lifespan. Subsequently, the minimal myelosuppression concurrently with number and timing of infusions and number of BM cells was determined to reach therapeutic threshold in SAD mice. Higher myelosuppression (2 Gy vs. 1 Gy) and cell number in single infusion led to increased chimerism. Importantly, administration of three-equivalent cell subdoses within 28 h of mild myelosuppression resulted in 100% recipient engraftment at therapeutic levels. These studies established the long-term therapeutic chimeric threshold of normal white blood cells at ,26% and determined the minimal fractionated BM/stem cell doses concomitant with mild myelosuppression for significant correction of SCD in SAD mice. [source]

Cobalt Deposits of China: Classification, Distribution and Major Advances

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 2 2004
FENG Chengyou
Abstract, The important strategic metal cobalt has diverse uses and the majority of world cobalt deposits have been found in China. The deposits can be classified into four types, i.e., magmatic Ni-Cu-Co sulfide deposits, hydrothermal and volcanogenic cobalt polymetallic deposits, strata-bound Cu-Co deposits hosted by sedimentary rocks and lateritic Ni-Co deposits, of which the former two types are the most important. There are six principal metallogenic epochs and seven important metallogenic belts according to their distribution and tectonic position. Although cobalt generally occurs in nickel-copper, copper and iron deposits as an associated metal, great developments in exploration for independent cobalt deposits have happened in China, and, in recent years, many independent deposits with different elementary assemblages and different genetic types have been discovered in the eastern part of the northern margin of the North China platform, the Central Orogenic Belt of China, western Jiangxi and northeastern Hunan. In addition, it is inferred that the Kunlun-Qinling Orogenic Belt has great potential for further exploration of new types of independent cobalt deposits. [source]

40Ar- 39Ar Dating of Albite and Phlogopite from Porphyry Iron Deposits in the Ningwu Basin in East-Central China and Its Significance

Hepatic and cardiac iron overload among patients with end-stage liver disease referred for liver transplantation

CLINICAL TRANSPLANTATION, Issue 5 2010
Avital Y. O'Glasser
O'Glasser AY, Scott DL, Corless CL, Zaman A, Sasaki A, Gopal DV, Rayhill SC, Orloff SL, Ham JM, Rabkin JM, Flora K, Davies CH, Broberg CS, Schwartz JM. Hepatic and cardiac iron overload among patients with end-stage liver disease referred for liver transplantation. Clin Transplant 2009 DOI: 10.1111/j.1399-0012.2009.01136.x. © 2009 John Wiley & Sons A/S. Abstract:,Background:, Iron overload is associated with fatal cardiovascular events following liver transplantation. Myocardial iron deposits were observed post-mortem in patients who died of cardiac events after transplantation at our institution. This observation prompted testing to exclude cardiac iron in subsequent transplant candidates. Aims:, To assess the results of testing for iron overload in liver transplant candidates at our institution. Methods:, Ferritin, TIBC, and serum iron were measured in cirrhotics referred for transplantation. Patients with transferrin saturation ,50% and ferritin ,250 ng/mL underwent liver biopsy graded for iron. Patients with 3,4+ hepatic iron deposits underwent HFE mutation analysis and endomyocardial biopsy with iron staining. Results:, Eight hundred and fifty-six patients were evaluated for liver transplantation between January 1997 and March 2005. Two hundred and eighty-seven patients (34%) had transferrin saturation ,50% and ferritin ,250 ng/mL. Patients with markers of iron overload had more advanced liver disease than those with normal iron indices. One hundred and fifty-three patients underwent liver biopsy. Twenty-six patients (17%) had 3,4+ hepatic iron staining. One patient was a C282Y heterozygote. Endomyocardial biopsy was performed in 14 patients of whom nine had cardiac iron deposition. Conclusions:, Non-HFE-related cardiac iron overload can occur in advanced liver disease We therefore recommend screening for cardiac iron prior to liver transplantation. [source]