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Iron absorption

Amat Bah, Sant-Rayn Pasricha, Momodou W Jallow, Ebrima A Sise, Rita Wegmuller, Andrew E Armitage, Hal Drakesmith, Sophie E Moore, Andrew M Prentice
Background: Antenatal anemia is a risk factor for adverse maternal and fetal outcomes and is prevalent in sub-Saharan Africa. Less than half of antenatal anemia is considered responsive to iron; identifying women in need of iron may help target interventions. Iron absorption is governed by the iron-regulatory hormone hepcidin.Objective: We sought to characterize changes in hepcidin and its associations with indexes of iron stores, erythropoiesis, and inflammation at weeks 14, 20, and 30 of gestation and to assess hepcidin's diagnostic potential as an index of iron deficiency...
April 19, 2017: Journal of Nutrition
Bridget J Milorey, Dmitry Malyshka, Reinhard Schweitzer-Stenner
The conformational changes of ferricytochrome c upon binding to cardiolipin-containing small unilamellar vesicles were studied at slightly acidic pH using fluorescence, visible circular dichroism, UV/visible absorption, and resonance Raman spectroscopy. The obtained spectroscopic response data suggest a mode of interaction, which is clearly distinct from the binding process observed at neutral pH. Evidence for a reversible and electrostatic binding mechanism under these conditions is provided through binding inhibition in the presence of 150 mM NaCl...
April 18, 2017: Journal of Physical Chemistry Letters
Meredith A Atkinson, Bradley A Warady
Anemia is common and associated with adverse outcomes in children with chronic kidney disease (CKD). Many factors contribute to declining hemoglobin as CKD progresses, but impaired production of erythropoietin by failing kidneys is a central cause. Hepcidin-mediated iron restriction also contributes to anemia by downregulating both intestinal iron absorption and release of stored iron for erythropoiesis. The core components of anemia management remain erythropoiesis-stimulating agents (ESA) and iron supplementation, but despite these therapies, a substantial number of children remain anemic...
April 15, 2017: Pediatric Nephrology: Journal of the International Pediatric Nephrology Association
Hannes Steinkellner, Himanshu Narayan Singh, Martina U Muckenthaler, Hans Goldenberg, Rajeswari R Moganty, Barbara Scheiber-Mojdehkar, Brigitte Sturm
Friedreich's ataxia (FRDA) is a neurodegenerative disease caused by reduced expression of the protein frataxin. Frataxin is thought to play a role in iron-sulfur cluster biogenesis and heme synthesis. In this study, we used erythroid progenitor stem cells obtained from FRDA patients and healthy donors to investigate the putative role, if any, of frataxin deficiency in heme synthesis. We used electrochemiluminescence and qRT-PCR for frataxin protein and mRNA quantification. We used atomic absorption spectrophotometry for iron levels and a photometric assay for hemoglobin levels...
April 12, 2017: Gene
Cameron J Ollson, Euan Smith, Paul Herde, Albert L Juhasz
In this study, the influence of sample matrix on the relative bioavailability of arsenic (As), cadmium (Cd) and lead (Pb) was assessed following exposure of C57BL/6 mice to spiked aged (12years) soils. AIN93G mouse chow was amended with individual and tertiary As, Cd and Pb soil combinations which were administered to mice over a 9day exposure period. Contaminant relative bioavailability was calculated by comparing As urinary excretion and Cd-kidney/Pb-liver accumulation to corresponding values for compounds used to derive the respective toxicity reference value...
April 10, 2017: Science of the Total Environment
Martin E McBriarty, Jennifer A Soltis, Sebastien N Kerisit, Odeta Qafoku, Mark E Bowden, Eric J Bylaska, James J De Yoreo, Eugene S Ilton
The characterization of trace elements in minerals using extended X-ray absorption fine structure (EXAFS) spectroscopy constitutes a first step toward understanding how impurities and contaminants interact with the host phase and the environment. However, limitations to EXAFS interpretation complicate the analysis of trace concentrations of impurities that are distributed across multiple phases in a heterogeneous system. Ab initio molecular dynamics (AIMD)-informed EXAFS analysis was employed to investigate the immobilization of trace uranium associated with nanophase iron (oxyhydr)oxides, a model system for the geochemical sequestration of radiotoxic actinides...
April 13, 2017: Environmental Science & Technology
Yanni Hua, Chaomeng Wang, Huijuan Jiang, Yihao Wang, Chunyan Liu, Lijuan Li, Hui Liu, Zonghong Shao, Rong Fu
The objective of the study was to examine levels of intracellular iron, reactive oxygen species (ROS) and the expression of JNK and p38MAPK in NK cells and hematopoietic stem/progenitor cells (HSPCs) in MDS patients, and explore potential mechanisms by which iron overload (IOL) promotes MDS progression. Thirty-four cases of MDS and six cases of AML transformed from MDS (MDS/AML) were included. HSPCs and NK cells were isolated by magnetic absorption cell sorting. We used flow cytometry to detect the levels of ROS and intracellular JNK and P38 in NK cells and HSPCs...
April 12, 2017: International Journal of Hematology
Matthew A Conger, Deepika Pokhrel, Matthew D Liptak
The micromolar equilibrium constants for heme dissociation from IsdG and IsdI reported in the literature call into question whether these enzymes are actually members of the iron-regulated surface determinant system of Staphylococcus aureus, which harvests heme iron from a host during infection. In order to address this question, the heme dissociation constants for IsdG and IsdI were reevaluated using three approaches. The heme dissociation equilibrium constants were measured using a UV/Vis absorption-detected assay analyzed with an assumption-free model, and using a newly developed fluorescence-detected assay...
April 12, 2017: Metallomics: Integrated Biometal Science
Andrzej Zadlo, Anna Pilat, Michal Sarna, Anna Pawlak, Tadeusz Sarna
With aging, retinal pigment epithelium melanosomes, by fusion with the age pigment lipofuscin, form complex granules called melanolipofuscin. Lipofuscin granules may contain oxidized proteins and lipid hydroperoxides, which in melanolipofuscin could chemically modify melanin polymer, while transition metal ions present in melanin can accelerate such oxidative modifications. The aim of this research was to examine the effect of selected transition metal ions on melanin susceptibility to chemical modification induced by the water-soluble tert-butyl hydroperoxide used as an oxidizing agent...
April 11, 2017: Cell Biochemistry and Biophysics
Mobinul Islam, Ghulam Ali, Min-Gi Jeong, Wonchang Choi, Kyung Yoon Chung, Hun-Gi Jung
Nickel ferrite (NiFe2O4) previously shown to have promising electrochemical performance as anode materials for lithium ion batteries (LIBs). However, associated electrochemical processes and structural changes during conversion-reaction remain unrevealed. Nano-crystalline NiFe2O4 was synthesized with the aid of a simple and easily scalable sol-gel method and tested as an anode for LIBs. The synthesized NiFe2O4 electrode provided a stable reversible capacity of 786 mAh g-1 at a constant current density of 0...
April 11, 2017: ACS Applied Materials & Interfaces
Ali Muhammad Yousafzai, Farhad Ullah, Fathul Bari, Sumayya Raziq, Mehreen Riaz, Khalid Khan, Umar Nishan, Iram Alam Sthanadar, Baseerat Shaheen, Mussarrat Shaheen, Habib Ahmad
We examined and compared heavy metals bioaccumulation in Cyprinus carpio and Labeo rohita netted from Sardaryab, a tributary of River Kabul. By using atomic absorption spectrometry we assessed different organs including livers, gills, and muscles. Metals studied were chromium, iron, zinc, lead, and copper. Livers of both species showed higher concentrations of metals while muscles showed the least amount. Chromium and iron were the highly concentrated metals in the gills and livers of both species. A quantity of 0...
2017: BioMed Research International
Yasumi Horimoto, Loong-Tak Lim
One of the causes of iron deficiency in human is poor absorption of non-heme iron from the diet. While proteins from meats have been reported in the literature to enhance the absorption of non-heme iron, other proteins, such as those from egg, are known to inhibit iron absorption. The objective of this study is to investigate non-heme iron binding property of egg white proteins hydrolyzed using pepsin and a combination of bacterial/fungal proteases. The iron bioavailability of non-heme iron, in the presence of egg white (EW) hydrolysates, was evaluated in vitro using a tissues culture model system - rat intestinal epithelial cells (IEC-6)...
May 2017: Food Research International
Masato Onzuka, Yukari Sekine, Takeshi Uchida, Koichiro Ishimori, Shin-Ichi Ozaki
Some Gram-negative pathogens import host heme into the cytoplasm and utilize it as an iron source for their survival. We report here that HmuS, encoded by the heme utilizing system (hmu) locus, cleaves the protoporphyrin ring to release iron from heme. A liquid chromatography/mass spectrometry analysis revealed that the degradation products of this reaction are two biliverdin isomers that result from transformation of a verdoheme intermediate. This oxidative heme degradation by HmuS required molecular oxygen and electrons supplied by either ascorbate or NADPH...
April 3, 2017: Biochimica et Biophysica Acta
Andreas K C Mengel, Christian Bissinger, Matthias Dorn, Oliver Back, Christoph Förster, Katja Heinze
Reversing the 3MLCT / 3MC excited state order in iron(II) complexes is a challenging objective, yet would finally result in longsought luminescent transition metal complexes with an earthabundant central ion. One approach to achieve this goal is based on low-energy charge transfer absorptions in combination with a strong ligand field. Coordinating electron rich and electron poor tridentate oligopyridine ligands with large bite angles at iron(II) enables both low-energy MLCT absorption bands around 590 nm and a strong ligand field...
April 6, 2017: Chemistry: a European Journal
P Scardi, L Rebuffi, M Abdellatief, A Flor, A Leonardi
Synchrotron radiation X-ray diffraction (XRD) patterns from an extensively ball-milled iron alloy powder were collected at 100, 200 and 300 K. The results were analysed together with those using extended X-ray absorption fine structure, measured on the same sample at liquid nitrogen temperature (77 K) and at room temperature (300 K), to assess the contribution of static disorder to the Debye-Waller coefficient (Biso). Both techniques give an increase of ∼20% with respect to bulk reference iron, a noticeably smaller difference than reported by most of the literature for similar systems...
April 1, 2017: Journal of Applied Crystallography
Wojciech Szczerba, Rocio Costo, Sabino Veintemillas-Verdaguer, Maria Del Puerto Morales, Andreas F Thünemann
This article reports on the characterization of four superparamagnetic iron oxide nanoparticles stabilized with dimercaptosuccinic acid, which are suitable candidates for reference materials for magnetic properties. Particles p1 and p2 are single-core particles, while p3 and p4 are multi-core particles. Small-angle X-ray scattering analysis reveals a lognormal type of size distribution for the iron oxide cores of the particles. Their mean radii are 6.9 nm (p1), 10.6 nm (p2), 5.5 nm (p3) and 4.1 nm (p4), with narrow relative distribution widths of 0...
April 1, 2017: Journal of Applied Crystallography
Susan J Fairweather-Tait, Amy Jennings, Linda J Harvey, Rachel Berry, Janette Walton, Jack R Dainty
Background: Values for dietary iron bioavailability are required for setting dietary reference values. These are estimated from predictive algorithms, nonheme iron absorption from meals, and models of iron intake, serum ferritin concentration, and iron requirements.Objective: We developed a new interactive tool to predict dietary iron bioavailability.Design: Iron intake and serum ferritin, a quantitative marker of body iron stores, from 2 nationally representative studies of adults in the United Kingdom and Ireland and a trial in elderly people in Norfolk, United Kingdom, were used to develop a model to predict dietary iron absorption at different serum ferritin concentrations...
April 5, 2017: American Journal of Clinical Nutrition
O Linnik, N Chorna, N Smirnova
The synthesized undoped and nitrogen doped iron titanate films treated at 450 and 500 °C were crystallized forming pseudobrookite and landauite phase as shown by XRD patterns. The presence of urea in the synthesis procedure promoted the crystallization rate. XPS data indicated that iron ions existed in divalent and trivalent forms, and their ratio was changed for nitrogen-doped sample. The formation of the complexes between iron and urea during sol aging with the following reduction of Fe(3+) to Fe(2+) within calcination can be a reason not only for accumulation of iron onto the surface as shown by EDS but also for twice increase of divalent iron as registered by XPS...
December 2017: Nanoscale Research Letters
Vincenzo Iannotti, Alessio Adamiano, Giovanni Ausanio, Luciano Lanotte, Giuliana Aquilanti, John Michael David Coey, Marco Lantieri, Gabriele Spina, Maria Fittipaldi, George Margaris, Kalliopi Trohidou, Simone Sprio, Monica Montesi, Silvia Panseri, Monica Sandri, Michele Iafisco, Anna Tampieri
Doping of biocompatible nanomaterials with magnetic phases is currently one of the most promising strategies for the development of advanced magnetic biomaterials. However, especially in the case of iron-doped magnetic hydroxyapatites, it is not clear if the magnetic features come merely from the magnetic phases/ions used as dopants or from complex mechanisms involving interactions at the nanoscale. Here, we report an extensive chemical-physical and magnetic investigation of three hydroxyapatite nanocrystals doped with different iron species and containing small or no amounts of maghemite as a secondary phase...
April 5, 2017: Inorganic Chemistry
Lukas Bucinsky, Martin Breza, Wei-Tsung Lee, Anne K Hickey, Diane A Dickie, Ismael Nieto, Jordan A DeGayner, T David Harris, Karsten Meyer, J Krzystek, Andrew Ozarowski, Joscha Nehrkorn, Alexander Schnegg, Karsten Holldack, Rolfe H Herber, Joshua Telser, Jeremy M Smith
High-oxidation-state metal complexes with multiply bonded ligands are of great interest for both their reactivity as well as their fundamental bonding properties. This paper reports a combined spectroscopic and theoretical investigation into the effect of the apical multiply bonded ligand on the spin-state preferences of threefold symmetric iron(IV) complexes with tris(carbene) donor ligands. Specifically, singlet (S = 0) nitrido [{PhB(Im(R))3}FeN], R = (t)Bu (1), Mes (mesityl, 2) and the related triplet (S = 1) imido complexes, [{PhB(Im(R))3}Fe(NR')](+), R = Mes, R' = 1-adamantyl (3), (t)Bu (4), were investigated by electronic absorption and Mössbauer effect spectroscopies...
April 5, 2017: Inorganic Chemistry
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