Elevated Iron Concentrations Research Articles

The occurrence of gold in hydrothermal sulfide at Southwest Indian Ridge 49.6°E

Massive sulfide precipitates found in the Southwest Indian Ridge (SWIR) 49.6A degrees E hydrothermal field are enriched in gold. Here, the mineralogy and mineral chemistry of these massive sulfides to constrain the process of gold precipitation were studied. Sulfide samples in this field include lower-temperature Zn-rich sulfides and relative higher-temperature Fe-rich sulfides. Zn-rich sulfides are dominated by sphalerite-pyrite-chalcopyrite assemblages, with concentrations of gold ranging from 9.08 to 17.0 A mu g/g. Fe-rich sulfides consist mainly of pyrite-marcasite-isocubanite assemblages, with gold concentrations from 2.17 to 3.79 A mu g/g. The significant enrichment in gold within the lower-temperature Zn-rich sulfides and the effective separation of Zn and Fe in hydrothermal precipitates at the surface of this field are here interpreted to reflect the strong temperature dependence of gold transportation and deposition within the sulfides. In Zn-rich samples, large amounts of isolated native gold grains were identified. They were found mainly as inclusions up to 8 A mu m in diameter, occupying porous cavities in sphalerite or in the elevated iron content rim of sphalerite. The fineness of the gold ranged from 810 to 830. Unlike previously published results on other hydrothermal fields, these data show a low gold fineness values in SWIR 49.6A degrees E. The FeS content of sphalerite associated with gold grains ranged from 3.2 mole % to 18.9 mole %. This was higher than in other fields, indicating that the sulfur activity is relatively low during the gold precipitation process and that sulfur activity may be one of the main factors affecting gold fineness in the SWIR 49.6A degrees E hydrothermal field. Evidence regarding gold fineness and sulfur activity suggests that gold was quite likely transported as AuHS0 rather than as a Au(HS) (2) (-) complex.

Simulation of soil water dynamics and rice crop growth as affected by bunding and fertilizer application in inland valley systems of West Africa

Rice production in rainfed inland systems is constrained by rainfall distribution and the heterogeneity of the topography that frequently lead to runoff causing erosion and loss of nutrients especially nitrogen. The use of water-saving and nutrient management technologies such as bunding and fertilizer application could help farmers maintain soil moisture and reduce nutrient losses thereby increase rice production. This study used the crop model EPIC (Environmental Policy Integrated Climate) to assess soil water dynamics and rice crop growth as affected by bunding and fertilizer application in inland valley systems of West Africa. The model was parameterized using observed soil water characteristics and crop parameters and run against observation data collected from 2007 to 2010 in a factorial trial combining bund and fertilizer rate. Simulation of soil water condition was satisfactory for unbunded conditions with coefficients of determination (R2) from comparison between simulated and observed soil water content between 0.64 and 0.68 depending on soil depth. Depth of ponded water during the growing period was adequately predicted in three out of four years. Simulated LAI development, total aboveground biomass and grain yield compared well with field observations in unbunded plots, the MRE (mean relative error) of simulated yield was 6–18%. In bund plots in 2009 and 2010, the grain yield was overestimated by the model when no fertilizer was applied (MRE=45%). Although negative effect of elevated iron concentration in the rice plant reduces the model performance, it was used to indicate effective effect of iron on the growth of crop the presence of bund in very wet year. The general use of the model for rainfed rice production at a large scale requires identification of areas with iron toxicity risk.

Abstract 293: Mammalian Target of Rapamycin and Tristetraprolin Regulate Iron Homeostasis in Cardiac Cells

Introduction: Iron is essential for normal heart function, and disruption of iron homeostasis can lead to cardiomyopathy. However, our understanding of iron regulation on a cellular level is incomplete, with a single model involving iron regulatory proteins (IRP) described to date. Here, we report the existence of a parallel iron regulatory pathway by energy sensor mTOR and inflammatory mediator trsitetraprolin (TTP). Results: To examine the role of energy metabolism in the regulation of cellular iron, we used rapamycin to inhibit mTOR pathway in H9c2 cardiac myoblasts and mouse embryonic fibroblasts (MEFs). Rapamycin treatment significantly elevated cellular iron content through a coordinated reduction in iron import (transferrin receptor, TfR1) and iron export (ferroportin, Fpn1), leading to deceleration of iron flux and net iron accumulation. We found that the primary action of rapamycin was to reduce TfR1 through destabilization of its mRNA. Surprisingly, this effect was not mediated by IRP1/2, the “classical” sensors of cellular iron levels, as TfR1 mRNA levels were significantly reduced by rapamycin even in cells with the genetic knockout of IRP1 and IRP2. In yeast, a tandem zinc finger (TZF) protein Cth2 was found to conserve cellular iron in states of deficiency by preferentially degrading mRNA of non-essential iron-containing proteins thus reducing iron requirements and liberating iron for vital functions. We found that the mammalian TZF protein TTP, an established mediator of inflammation, was greatly induced by iron deficiency, enhanced degradation of iron-containing proteins, and complemented Cth2 deletion in yeast, thus establishing TTP as the functional homolog of Cth2 in mammalian iron regulation. Finally, TTP levels were increased by rapamycin in IRP1/2-independent manner, and genetic knockout of TTP in MEFs significantly reversed the effects of rapamycin on TfR1 mRNA levels and stability. These findings establish TTP as the mediator of iron-regulatory effects of mTOR and provide a novel link between energy metabolism, inflammation and iron regulatory pathways. Conclusions: We identified a novel pathway of cellular iron regulation by mTOR and TTP, which complements the “classical” IRP1/2 model.

Oxidation state of subarc mantle

Research Article| September 01, 2012 Oxidation state of subarc mantle K.A. Evans; K.A. Evans 1School of Applied Geology, Curtin University, GPO Box 1987, WA 6845, Australia Search for other works by this author on: GSW Google Scholar M.A. Elburg; M.A. Elburg 2Department of Geology and Soil Science, Ghent University, Krijgslaan 281 S8, 9000 Ghent, Belgium3School of Geological Sciences, University of KwaZulu-Natal, Private Bag x54001, 4000 Durban, South Africa Search for other works by this author on: GSW Google Scholar V.S. Kamenetsky V.S. Kamenetsky 4School of Earth Sciences, and CODES Centre of Excellence in Ore Deposits, University of Tasmania, Hobart, Tasmania 7001, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information K.A. Evans 1School of Applied Geology, Curtin University, GPO Box 1987, WA 6845, Australia M.A. Elburg 2Department of Geology and Soil Science, Ghent University, Krijgslaan 281 S8, 9000 Ghent, Belgium3School of Geological Sciences, University of KwaZulu-Natal, Private Bag x54001, 4000 Durban, South Africa V.S. Kamenetsky 4School of Earth Sciences, and CODES Centre of Excellence in Ore Deposits, University of Tasmania, Hobart, Tasmania 7001, Australia *E-mail: k.evans@curtin.edu.au; elburg@ukzn.ac.za; dima.kamenetsky@utas.edu.au. Publisher: Geological Society of America Received: 18 Nov 2011 Revision Received: 12 Feb 2012 Accepted: 24 Mar 2012 First Online: 09 Mar 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2012 Geological Society of America Geology (2012) 40 (9): 783–786. https://doi.org/10.1130/G33037.1 Article history Received: 18 Nov 2011 Revision Received: 12 Feb 2012 Accepted: 24 Mar 2012 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation K.A. Evans, M.A. Elburg, V.S. Kamenetsky; Oxidation state of subarc mantle. Geology 2012;; 40 (9): 783–786. doi: https://doi.org/10.1130/G33037.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The subarc mantle is a primary control on the composition of arc magmas and the formation of arc-related ore deposits. Elevated ferric iron contents in arc lavas have been interpreted as a record of subarc mantle that is oxidized relative to mid-oceanic ridge basalt (MORB), but this conclusion is controversial. Measurements of spinel compositions in primitive arc lavas imply an arc magma source 1–4 log units more oxidized than MORB and ocean island basalts analyzed using the same technique. Samples from seven arcs show a significant correlation (P < 0.0005) between redox budget, subduction zone convergence rate, and subduction zone age. These results support the notion of oxidized arc lavas in the mantle source zone, but resolution of contradictory evidence regarding subarc mantle redox state requires further work. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Differential participation of phospholipase A2 isoforms during iron-induced retinal toxicity. Implications for age-related macular degeneration

Both elevated iron concentrations and the resulting oxidative stress condition are common signs in retinas of patients with age-related macular degeneration (AMD). The role of phospholipase A2 (PLA2) during iron-induced retinal toxicity was investigated. To this end, isolated retinas were exposed to increasing Fe2+ concentrations (25, 200 or 800μM) or to the vehicle, and lipid peroxidation levels, mitochondrial function, and the activities of cytosolic PLA2 (cPLA2) and calcium-independent PLA2 (iPLA2) were studied. Incubation with Fe2+ led to a time- and concentration-dependent increase in retinal lipid peroxidation levels whereas retinal cell viability was only affected after 60min of oxidative injury.A differential release of arachidonic acid (AA) and palmitic acid (PAL) catalyzed by cPLA2 and iPLA2 activities, respectively, was also observed in microsomal and cytosolic fractions obtained from retinas incubated with iron. AA release diminished as the association of cyclooxigenase-2 increased in microsomes from retinas exposed to iron. Retinal lipid peroxidation and cell viability were also analyzed in the presence of cPLA2 inhibitor, arachidonoyl trifluoromethyl ketone (ATK), and in the presence of iPLA2 inhibitor, bromoenol lactone (BEL). ATK decreased lipid peroxidation levels and also ERK1/2 activation without affecting cell viability. BEL showed the opposite effect on lipid peroxidation. Our results demonstrate that iPLA2 and cPLA2 are differentially regulated and that they selectively participate in retinal signaling in an experimental model resembling AMD.

Response to Comment on: Ellervik et al. Elevated Transferrin Saturation and Risk of Diabetes: Three Population-Based Studies. Diabetes Care 2011;34:2256–2258

We thank Conway for her comment (1) on our article in Diabetes Care (2) on the risk of diabetes associated with elevated transferrin saturation levels in two follow-up studies (risk as hazard ratios and exposure preceding disease) and a case-control study (risk as odds ratio) with neither study being cross-sectional. We agree with Conway that the pathophysiology of diabetes is complex. We acknowledge that elevated cellular iron concentrations in insulin-sensitive tissue and the pancreatic …

Arthrobacter agilis UMCV2 induces iron acquisition in Medicago truncatula (strategy I plant) in vitro via dimethylhexadecylamine emission

Background and aims Iron is an essential nutrient for plant growth. Although abundant in soil, iron is poorly available. Therefore, plants have evolved mechanisms for iron mobilization and uptake from the rhizospheric environment. In this study, we examined the physiological responses to iron deficiency in Medicago truncatula plants exposed to volatile organic compounds (VOCs) produced by Arthrobacter agilis UMCV2. Methods The VOC profiles of the plant and bacterium were determined separately and during interaction assays using gas chromatography. M. truncatula plants exposed to A. agilis VOCs and pure dimethylhexadecylamine were transferred to conditions of iron deficiency, and parameters associated with iron nutritional status were measured. Results The relative abundance of the bacterial VOC dimethylhexadecylamine increased 12-fold when in co-cultures of A. agilis and M. truncatula, compared to axenic cultures. Plants exposed to bacterial VOCs or dimethylhexadecylamine exhibited a higher rhizosphere acidification capacity, enhanced ferric reductase activity, higher biomass generation, and elevated chlorophyll and iron content relative to controls. Conclusions The VOCs emitted by A. agilis UMCV2 induce iron acquisition mechanisms in vitro in the Strategy I plant M. truncatula. Dimethylhexadecylamine is the signal molecule responsible for producing the beneficial effects.

Model and field observations of effects of circulation on the timing and magnitude of nitrate utilization and production on the northern Gulf of Alaska shelf

The GLOBEC program was tasked with understanding the mechanistic links between climate forcing and the ocean-ecosystem response on the northern Gulf of Alaska (GOA) shelf. To address this task, samples were collected five to six times times annually along the Seward Line between 1998 and 2004. However, interpreting Seward-Line field observations in space and time is complicated by the complex circulation on the GOA shelf. The Alaska Current/Alaskan Stream and Alaska Coastal Current produce eddies and meanders which mix the iron-limited small-cell oceanic community with the iron-rich large-cell coastal community. Thus observations at any point in space and time are the result of the degree of mixing of the oceanic and coastal water masses. The ROMS circulation model with an embedded ecosystem model was used to extend GLOBEC observations in space and time on the GOA shelf. The timing of the spring bloom in simulations was related to shallowing of the pycnocline. The spring bloom began in late March–April on the inner shelf and in May on the mid and outer shelf. The simulations suggest that the magnitude of shelf production is a balance between the amount of iron from freshwater runoff and nitrate, with iron limitation on the outer shelf and adjacent ocean and nitrate limitation on the inner shelf. Simulated shelf-break eddies form near Yakutat, have elevated iron concentrations relative to surrounding waters, and propagate westward, influencing production and nitrate concentrations on the outer shelf and in the adjacent ocean during spring and summer. Simulated primary production in the Seward Line region was about 100–130gcm−2y−1, but production of up to 300gcm−2y−1 is predicted for regions in Lower Cook Inlet and around Kodiak.

Effect of elevated concentrations of strontium and iron on the structural and dielectric characteristics of Ba(1−x−y)Sr(x)Ti Fe(y)O3 prepared through sol–gel technique

Nano-composite Ba1−xSr(x)TiO3 (BST), where x=0.01–0.50 and doped with different concentrations of iron Ba(1−x−y)Sr(x)TiFe (y)O3 (BSTF), where x=0.01 and y=0.01–0.05 powders were prepared by sol–gel method.The effect of increasing the iron and strontium concentrations substituted in Barium strontium titanate system will be studied. The prepared samples have a tetragonal crystalline phase after sintering for 1h at 750°C in air. The structural and the morphological features of the systems have been studied using X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). The dielectric properties of the BST and BSTF systems have been investigated as a function of temperature and frequency. The dielectric measurements are carried out in the frequency range 42Hz–1MHz, at a temperature ranging between 25 and 250°C.The results showed a decrease in Tc temperature giving the following values 90 and 85°C for B10ST and B10ST5F prepared powder samples, respectively, implying tetragonal, feroelectric phase at lower temperature into cubic, para-electric phase at temperature higher than Tc.

Secondary sulfate mineralization and basaltic chemistry of craters of the Moon National Monument, Idaho: Potential martian analog

Craters of the Moon National Monument (COM) basalts offer a reasonable analog to martian basalts, as they have elevated iron concentrations compared to traditional terrestrial analogs. Although secondary sulfate minerals on the evaporitic regions of Mars consist primarily of Mg-, Ca-, and Fe-bearing sulfate minerals, recent orbiter spectroscopic data have suggested Na-sulfate minerals may be present. Secondary minerals in the basaltic caves of COM in southern Idaho are white, efflorescent deposits in small cavities along the cave walls and ceilings and localized mounds on the cave floors. These deposits were examined using X-ray powder diffraction (XRD), X-ray fluorescence spectrometry (XRF), Fourier transform infrared spectrometry (FTIR), and laser desorption Fourier transform ion cyclotron mass spectrometry (LD-FTICRMS). The secondary mineral assemblages were dominated by Na-sulfate minerals (thenardite, mirabilite) with a small fraction of the deposits containing minor concentrations of Na-carbonate minerals. Based on thermodynamic modeling results, formation of the deposits was attributed to leaching of basalt minerals by meteoritic water followed by evaporation of solutions. Such deposits could form under similar conditions in basaltic caves on Mars, making caves an excellent target for astrobiological investigations.

Haemochromatosis in a Brazilian tapir (Tapirus terrestris) in an Australian zoo

A 23-year-old Brazilian, or lowland, tapir with a 6-month history of loss of body condition developed clinical signs and laboratory findings consistent with liver failure. The animal was euthanased and a diagnosis of hepatic haemochromatosis was made based on histopathology. Two other healthy tapirs in the same collection had chronically elevated serum and tissue iron concentrations. The excessive accumulation of iron in tissues with resultant tissue damage (i.e. haemochromatosis) has been reported in a range of captive species. This and other reported cases of haemochromatosis in the Brazilian tapir would suggest that this condition is an important consideration in the management of this species in zoos. Further research into the endogenous regulation of iron metabolism, especially the role of hepcidin, in tapirs and other species at risk of iron storage disorders may be helpful in the prevention of this condition.

Diagnosis of Iron Overload and Heart Disease by Magnetic Resonance Imaging

The use of Magnetic resonance imaging (MRI) to estimate tissue iron was initiated nearly three decades ago but has only become a practical reality in the last ten years. MRI is most often used to estimate hepatic and cardiac iron in patients with thalassemia or sickle cell disease and has largely replaced liver biopsy for liver iron quantification. The ability of MRI to image extra hepatic organs has really transformed our understanding of iron mediated toxicity in transfusional siderosis. For decades, iron cardiomyopathy was the leading cause of death in thalassemia major, but it is now relatively rare in centers with regular MRI screening. Early recognition of cardiac iron loading allows more gentle modifications of iron chelation therapy prior to life threatening organ dysfunction. Serial MRI evaluations have demonstrated differential kinetics of uptake and clearance among the difference organs of the body. Although elevated serum ferritin and liver iron concentration increase the risk of cardiac and endocrine toxicities, extra hepatic iron deposition and toxicity occurs in many patients despite having low total body iron stores; there is no safe liver iron level in chronically transfused patients. Instead, the type, dose, and pattern of iron chelation therapy all contribute to whether cardiac iron accumulation will occur. These observations, coupled with the advent of increasing options for iron chelation therapy, are allowing clinicians to more appropriately tailor chelation therapy to individual patient needs, producing greater efficacy with fewer toxicities. With the decline in cardiac mortality, future frontiers in MRI monitoring including better prevention of endocrine toxicities, particularly hypogonadotropic hypogonadism and diabetes. These organs also serve as early warning signals for inadequate control of non-transferrin bound iron, a risk factor for cardiac iron loading. Thus MRI assessment of extra hepatic iron stores is a critical monitoring tool for chronically transfused patients. Further prospective work is necessary to determine whether markers of endocrine and exocrine pancreatic function can be used as surrogates of cardiac risk in regions where MRI is not available.

Mobilization of iron and arsenic from soil by construction and demolition debris landfill leachate

Column experiments were performed to examine (a) the potential for leachate from construction and demolition (C&D) debris landfills to mobilize naturally-occurring iron and arsenic from soils underlying such facilities and (b) the ability of crushed limestone to remove these aqueous phase pollutants. In duplicate columns, water was added to a 30-cm layer of synthetic C&D debris, with the resulting leachate serially passed through a 30-cm soil layer containing iron and arsenic and a 30-cm crushed limestone layer. This experiment was conducted for two different soil types (one high in iron (10,400mg/kg) and the second high in iron (5400mg/kg) and arsenic (70mg/kg)); also monitored were control columns for both soil types with water infiltration alone. Despite low iron concentrations in the simulated C&D debris leachate, elevated iron concentrations were observed when leachate passed through the soils; reductive dissolution was concluded to be the cause of iron mobilization. In the soil containing elevated arsenic, increased iron mobilization from the soil was accompanied by a similar but delayed arsenic mobilization. Since arsenic sorbs to oxidized iron soil minerals, reductive dissolution of these minerals results in arsenic mobilization. Crushed limestone significantly reduced iron (to values below the detection limit of 0.01mg/L in most cases); however, arsenic was not removed to any significant extent.

Impact of Iron Assessment by MRI

The use of magnetic resonance imaging (MRI) to estimate tissue iron was conceived in the 1980s, but has only become a practical reality in the last decade. The technique is most often used to estimate hepatic and cardiac iron in patients with transfusional siderosis and has largely replaced liver biopsy for liver iron quantification. However, the ability of MRI to quantify extrahepatic iron has had a greater impact on patient care and on our understanding of iron overload pathophysiology. Iron cardiomyopathy used to be the leading cause of death in thalassemia major, but is now relatively rare in centers with regular MRI screening of cardiac iron, through earlier recognition of cardiac iron loading. Longitudinal MRI studies have demonstrated differential kinetics of uptake and clearance among the difference organs of the body. Although elevated serum ferritin and liver iron concentration (LIC) increase the risk of cardiac and endocrine toxicities, some patients unequivocally develop extrahepatic iron deposition and toxicity despite having low total body iron stores. These observations, coupled with the advent of increasing options for iron chelation therapy, are allowing clinicians to more appropriately tailor chelation therapy to individual patient needs, producing greater efficacy with fewer toxicities. Future frontiers in MRI monitoring include improved prevention of endocrine toxicities, particularly hypogonadotropic hypogonadism and diabetes.

RNAi-Mediated Inhibition of Tmprss6 Elevates Hamp1 Expression and Reduces Serum Iron Levels in Mice

Abstract 1045The liver hormone Hepcidin (encoded by Hamp1) regulates serum iron levels by controlling the efflux of iron from intestinal enterocytes and macrophages. Maintaining sufficient iron levels to support erythropoiesis while preventing iron overload requires tight control of Hepcidin expression. Transcription of Hamp1 in hepatocytes is stimulated by high serum iron levels, via Transferrin Receptor signaling, as well as by activation of the BMP/SMAD pathway. The membrane serine protease Matriptase-2 (encoded by Tmprss6) inhibits BMP induced Hamp1 induction through the regulation of the BMP co-receptor, Hemojuvelin. In humans, loss of function mutations in TMPRSS6 lead to elevated Hepcidin levels resulting in iron-resistant iron-deficiency anemia (IRIDA). In diseases associated with iron overload, such as Thalassemia intermedia (TI) and Familial Hemochromatosis (FH), Hepcidin levels are low despite elevated serum iron concentrations. Studies in murine models of TI and FH have shown that elevating Hepcidin levels by genetic inactivation of Tmprss6 can prevent iron overload and correct aspects of the disease phenotype. Therefore, therapeutic strategies aimed at specifically inhibiting Tmprss6 expression could prove efficacious in these, and other, iron overloading diseases. Here we show that systemic administration of a potent lipid nanoparticle (LNP) formulated siRNA directed against Tmprss6 leads to durable inhibition of Tmprss6 mRNA in the mouse liver, with concomitant elevation of Hamp1 expression. This leads to significant decreases in serum iron concentration and Transferrin saturation, along with changes in hematologic parameters consistent with iron restriction. Further testing in mouse genetic models of TI and FH will support the rationale for developing LNP formulated Tmprss6 siRNA as a novel therapeutic modality. Disclosures:Toudjarska:Alnylam Pharmaceuticals, Inc.: Employment. Cai:Alnylam Pharmaceuticals, Inc.: Employment. Racie:Alnylam Pharmaceuticals, Inc.: Employment. Milstein:Alnylam Pharmaceuticals, Inc.: Employment. Bettencourt:Alnylam Pharmaceuticals, Inc.: Employment. Hettinger:Alnylam Pharmaceuticals, Inc.: Employment. Sah:Alnylam Pharmaceuticals, Inc.: Employment. Vaishnaw:Alnylam Pharmaceuticals, Inc.: Employment. Bumcrot:Alnylam Pharmaceuticals, Inc.: Employment.

Analysis of bacterial diversity and metals in produced water, seawater and sediments from an offshore oil and gas production platform

Produced water is one of the largest waste products routinely discharged into the ocean from offshore oil and gas platforms. This study analyzed bacterial communities and metals in the produced water, surrounding seawater, and sediment around the Thebaud platform. The bacterial community within the produced water was different from the seawater (SAB=13.3), but the discharge had no detectable effect on the bacterial communities in the seawater (SAB>97). In contrast, genomic analysis of sediments revealed that the bacterial community from 250m was different (SAB=70) from other locations further from the discharge, suggesting that the produced water had a detectable effect on the bacterial community in the sediment closest to the discharge. These near-field sediments contained elevated concentrations of manganese and iron that are associated with the produced water effluent. The results suggested that the discharge of produced water has influenced the bacterial community structure of sediments adjacent to the platform.

What Toxicity May Result from the Xenobiotic Responsible for the Finding on This Plain Film? Answer: Reduced Iron, Found in Heating Pads and Instant Hand Warmers, May Result in Elevated Serum Iron Concentrations and Subsequent Iron Toxicity

Disposable heating pads are commonly used products, with reduced iron as their active ingredient. Reduced iron is not expected to cause significant toxicity when ingested orally. We report a case of accidental heating pad ingestion seen on abdominal plain films that resulted in significantly elevated serum iron concentrations.

Evaluating waste concrete for the treatment of acid sulphate soil groundwater from coastal floodplains

The treatment of acidic groundwater generated from acid sulphate soil (ASS) terrain is a challenging environmental issue in coastal floodplains of Australia. In this study, a laboratory column experiment was conducted to assess the performance of waste concrete for treating the acidic groundwater leachate from ASS terrain of the Shoalhaven region of NSW. The groundwater was highly acidic (pH of 2.5–3.5) and contained elevated concentrations of iron (10–90 mg/L) and aluminium (30–45 mg/L). Passage of the acidic groundwater through the column filled with waste concrete resulted in a significant improvement in water quality. Reduction in the concentration of iron and aluminium to below detection limits and improvement of the pH from acidic to near-neutral (pH 6–8) were observed, along with a significant release of alkalinity over a six month period under controlled laboratory conditions. The results show that the working lifetime of waste concrete as the reactive media was governed primarily by the precipitation of secondary minerals despite the high acid neutralisation capacity of the waste concrete material.

Elevated liver iron concentration is a marker of increased morbidity in patients with thalassemia intermedia

Patients with β thalassemia intermedia can have substantial iron overload, irrespectively of their transfusion status, secondary to increased intestinal iron absorption. This study evaluates whether iron overload in patients with β thalassemia intermedia is associated with morbidity. This was a cross-sectional study of 168 patients with β thalassemia intermedia treated at two centers in Lebanon and Italy. Data on demographics, splenectomy status, transfusion status, and presence of co-morbidities were retrieved. Laboratory values of serum ferritin, fetal and total hemoglobin levels, as well as platelet and nucleated red blood cell counts were also obtained. Iron burden was determined directly by measuring liver iron concentration using magnetic resonance imaging. Patients were subdivided according to transfusion and splenectomy status into groups with phenotypes of different severity. The mean age of the patients was 35.2 ± 12.6 years and 42.9% of them were male. The mean liver iron concentration was 8.4 ± 6.7 mg Fe/g dry weight. On multivariate logistic regression analysis, after adjusting for age, gender, splenectomy status, transfusion status, and laboratory indices, an increase in 1 mg Fe/g dry weight liver iron concentration was independently and significantly associated with higher odds of thrombosis, pulmonary hypertension, hypothyroidism, osteoporosis, and hypogonadism. A liver iron concentration of at least 7 and at least 6 mg Fe/g dry weight were the best thresholds for discriminating the presence and absence of vascular and endocrine/bone morbidities, respectively (area under the receiver-operating characteristic curve: 0.72, P<0.001). Elevated liver iron concentration was associated with an increased rate of morbidity in patients with phenotypes of all severity, with a steeper increase in the rate of vascular morbidity being attributed to aging, and an earlier appearance of endocrine and bone disease. Elevated liver iron concentration in patients with β thalassemia intermedia is a marker of increased vascular, endocrine, and bone disease.

Mechanisms controlling dissolved iron distribution in the North Pacific: A model study

[1] Mechanisms controlling the dissolved iron distribution in the North Pacific are investigated using the Biogeochemical Elemental Cycling (BEC) model with a resolution of approximately 1° in latitude and longitude and 60 vertical levels. The model is able to reproduce the general distribution of iron as revealed in available field data: surface concentrations are generally below 0.2 nM; concentrations increase with depth; and values in the lower pycnocline are especially high in the northwestern Pacific and off the coast of California. Sensitivity experiments changing scavenging regimes and external iron sources indicate that lateral transport of sedimentary iron from continental margins into the open ocean causes the high concentrations in these regions. This offshore penetration only appears under a scavenging regime where iron has a relatively long residence time at high concentrations, namely, the order of years. Sedimentary iron is intensively supplied around continental margins, resulting in locally high concentrations; the residence time with respect to scavenging determines the horizontal scale of elevated iron concentrations. Budget analysis for iron reveals the processes by which sedimentary iron is transported to the open ocean. Horizontal mixing transports sedimentary iron from the boundary into alongshore currents, which then carry high iron concentrations into the open ocean in regions where the alongshore currents separate from the coast, most prominently in the northwestern Pacific and off of California.