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Isotope tracer

Erwann Le Gendre, Erwan Martin, Benoit Villemant, Pierre Cartigny, Nelly Assayag
RATIONALE: The O- and S- isotope compositions of sulfates can be used as key tracers of the fate and sink of sulfate in both terrestrial and extra-terrestrial environments. However, their application remains limited in those geological systems where sulfate occurs in low concentrations. Here we present a simple and reliable method to extract, purify and concentrate sulfate from natural samples. The method allows us to take into account the separation of nitrate, which is known to be an issue in O-isotope analysis...
October 21, 2016: Rapid Communications in Mass Spectrometry: RCM
Noelle Merchak, Virginie Silvestre, Denis Loquet, Toufic Rizk, Serge Akoka, Joseph Bejjani
Triacylglycerols, which are quasi-universal components of food matrices, consist of complex mixtures of molecules. Their site-specific (13)C content, their fatty acid profile, and their position on the glycerol moiety may significantly vary with the geographical, botanical, or animal origin of the sample. Such variables are valuable tracers for food authentication issues. The main objective of this work was to develop a new method based on a rapid and precise (13)C-NMR spectroscopy (using a polarization transfer technique) coupled with multivariate linear regression analyses in order to quantify the whole set of individual fatty acids within triacylglycerols...
October 19, 2016: Analytical and Bioanalytical Chemistry
M Brnić, R F Hurrell, L T Songré-Ouattara, B Diawara, A Kalmogho-Zan, C Tapsoba, C Zeder, R Wegmüller
BACKGROUND/OBJECTIVES: Fortifying cereal staples with zinc is a strategy for increasing zinc intake in young children in developing countries. However, phytic acid (PA) naturally present in cereals strongly decreases zinc absorption. A stable-isotope zinc absorption study was conducted in young children to investigate the ability of the PA-degrading enzyme phytase to improve zinc absorption, when added to a cereal porridge immediately before consumption. SUBJECTS/METHODS: Fractional absorption of zinc (FAZ) was estimated in 35 young healthy Burkinabe children using the double-isotopic tracer ratio method with (67)Zn as oral tracer and (70)Zn as intravenous tracer, in a crossover design...
October 19, 2016: European Journal of Clinical Nutrition
Victoria C Foletta, Michelle Palmieri, Joachim Kloehn, Shaun Mason, Stephen F Previs, Malcolm J McConville, Oliver M Sieber, Clinton R Bruce, Greg M Kowalski
Deuterated water (²H₂O), a stable isotopic tracer, provides a convenient and reliable way to label multiple cellular biomass components (macromolecules), thus permitting the calculation of their synthesis rates. Here, we have combined ²H₂O labelling, GC-MS analysis and a novel cell fractionation method to extract multiple biomass components (DNA, protein and lipids) from the one biological sample, thus permitting the simultaneous measurement of DNA (cell proliferation), protein and lipid synthesis rates...
October 13, 2016: Metabolites
Veronika Metlenko, WooChul Jung, Sean R Bishop, Harry L Tuller, Roger A De Souza
Oxygen transport in the mixed ionic-electronic conducting perovskite-oxides SrTi1-yFeyO3-δ (with y = 0.5 and y = 1.0) was studied by oxygen isotope exchange measurements. Experiments were performed on thin-film samples that were grown by Pulsed Laser Deposition (PLD) on MgO substrates. Isotope penetration profiles were introduced by (18)O2/(16)O2 exchanges into the plane of the films at various temperatures in the range 773 < T/K < 973 at an oxygen activity aO2 = 0.5. Isotope profiles were determined subsequently by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), and their analysis yielded tracer diffusion coefficients D* and oxygen surface exchange coefficients k*...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Cuiping Wang, Xinying Lin, Dongmei Guo, Lili Ding, Haifeng Guo, Guifa Xu, Xi Cui, Xia Wang
The objective of this study was to investigate the zinc fractional absorption of young Chinese men and women from the Shandong rural region under the routine dietary pattern by stable isotope technique. Ten men and 10 women, aged 20 to 35 years, and with a representative diet during the experiment were recruited from the Shandong rural region. Stable (67)Zn was used as a tracer to label ZnCl2, and Yb was used to monitor the excretion of (67)Zn in urine and feces. All volunteers were given rice containing 4...
October 15, 2016: Biological Trace Element Research
Kostja Renko, Carolin S Hoefig, Corinne Dupuy, Lisbeth Harder, Christian Schwiebert, Josef Köhrle, Lutz Schomburg
Iodotyrosine deiodinase (DEHAL1) is a crucial enzyme in iodine homeostasis. Unbound mono- and diiodotyrosines are indispensable byproducts of thyroid hormone biosynthesis. Their iodine needs to be recovered to avoid iodine deficiency, as observed in genetic defects in DEHAL1. Despite its importance, the enzyme is rarely studied. The deiodination process can be monitored by radioactive tracers or via techniques involving mass spectrometry (MS). However, isotope-labeled molecules are expensive, not always commercially available, and their use is legally restricted, while MS requires sophisticated, costly and sensitive instrumentation...
October 12, 2016: Endocrinology
Robert Kent, Matthew K Landon
From 2004 to 2011, the U.S. Geological Survey collected samples from 1686 wells across the State of California as part of the California State Water Resources Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) Priority Basin Project (PBP). From 2007 to 2013, 224 of these wells were resampled to assess temporal trends in water quality. The samples were analyzed for 216 water-quality constituents, including inorganic and organic compounds as well as isotopic tracers. The resampled wells were grouped into five hydrogeologic zones...
November 2016: Environmental Monitoring and Assessment
Cong-Hui Yao, Gao-Yuan Liu, Kui Yang, Richard W Gross, Gary J Patti
INTRODUCTION: Palmitate, the typical end product released from fatty acid synthase, is of interest to many researchers performing metabolomics. Although palmitate can be readily detected by using mass spectrometry, many metabolomic platforms involve the use of plastic consumables that introduce a competing background signal of palmitate. OBJECTIVES: The goal of this study was to quantify palmitate contamination in metabolomics and isotope tracer studies and to examine the reliability of approaches for reducing error...
September 2016: Metabolomics: Official Journal of the Metabolomic Society
Anubhav Srivastava, Greg M Kowalski, Damien L Callahan, Peter J Meikle, Darren J Creek
This is a perspective from the peer session on stable isotope labelling and fluxomics at the Australian & New Zealand Metabolomics Conference (ANZMET) held from 30 March to 1 April 2016 at La Trobe University, Melbourne, Australia. This report summarizes the key points raised in the peer session which focused on the advantages of using stable isotopes in modern metabolomics and the challenges in conducting flux analyses. The session highlighted the utility of stable isotope labelling in generating reference standards for metabolite identification, absolute quantification, and in the measurement of the dynamic activity of metabolic pathways...
October 1, 2016: Metabolites
Daniel A Wolf, Jacob Y Hesterman, Jenna M Sullivan, Kelly D Orcutt, Matthew D Silva, Merryl Lobo, Tyler Wellman, Jack Hoppin, Ajay Verma
The intrathecal (IT) dosing route offers a seemingly obvious solution for delivering drugs directly to the central nervous system. However, gaps in understanding drug molecule behavior within the anatomically and kinetically unique environment of the mammalian IT space have impeded the establishment of pharmacokinetic principles for optimizing regional drug exposure along the neuraxis. Here, we have utilized high-resolution single-photon emission tomography with X-ray computed tomography to study the behavior of multiple molecular imaging tracers following an IT bolus injection, with supporting histology, autoradiography, block-face tomography, and MRI...
February 25, 2016: JCI Insight
Amzad Hussain Laskar, Sasadhar Mahata, Mao-Chang Liang
Quantification of contribution from various sources of CO2 is important for understanding the atmospheric CO2 budget. Considering the number and diversity of sources and sinks, the widely used proxies such as concentration and conventional isotopic compositions (δ13C and δ18O) are not always sufficient to fully constrain the CO2 budget. Additional constraints may help in understanding the mechanisms of CO2 production and consumption. Anomaly in triple oxygen isotopes or 17O excess (denoted by Δ17O) and molecules containing two rare isotopes, called clumped isotopes, are two recently developed tracers with potentials to independently constrain some important processes that regulate CO2 in the atmosphere...
September 30, 2016: Environmental Science & Technology
Michael H Green, Jennifer Lynn Ford, Joanne Balmer Green
BACKGROUND: Retinol isotope dilution (RID) equations are used to determine vitamin A status and the efficacy of vitamin A intervention programs. Recent work related to RID methods has focused on modifying the "Olson equation" to improve the accuracy of predictions of vitamin A total body stores (TBS) in individual subjects. OBJECTIVE: We investigated the hypothesis that short-term restriction of vitamin A intake would result in accurate RID prediction of vitamin A TBS in individuals...
September 28, 2016: Journal of Nutrition
Anna Francová, Vladislav Chrastný, Hana Šillerová, Martina Vítková, Jana Kocourková, Michael Komárek
Samples of lichens, snow and particulate matter (PM10, 24 h) are used for the source identification of air pollution in the heavily industrialized region of Ostrava, Upper Silesia, Czech Republic. An integrated approach that uses different environmental samples for metal concentration and Pb isotope analyses was applied. The broad range of isotope ratios in the samples indicates a combination of different pollution sources, the strongest among them being the metallurgical industry, bituminous coal combustion and traffic...
September 22, 2016: Environmental Pollution
Rupali A Lagad, Sunil K Singh, Vinai K Rai
The increasing demand for premium priced Indian Basmati rice (Oryza sativa) in world commodity market causing fraudulent activities like adulteration, mislabelling. In order to develop authentication method for Indian Basmati rice, (87)Sr/(86)Sr ratios and REEs composition of Basmati rice, soil and water samples were determined and evaluated their ability as geographical tracer in the present study. In addition, the possible source of Sr in rice plant has also been examined. Basmati rice samples (n=82) showed (87)Sr/(86)Sr ratios in the range 0...
February 15, 2017: Food Chemistry
Jennifer K Yee, Guang Han, Juan Vega, Wai-Nang P Lee, Michael G Ross, Mina Desai
Intrauterine growth restriction (IUGR) with rapid catch-up growth leads to adult obesity and insulin resistance. We have previously shown that IUGR male rats demonstrated increased de novo fatty acid synthesis in the subcutaneous (SC) fat, but not the visceral fat, during the nursing period prior to the onset of obesity. Young IUGR females do not exhibit the same increase. We further hypothesized that in male IUGR offspring, de novo synthesis is a programmed intrinsic effect that persists to adulthood and does not suppress in response to a high fat diet...
September 22, 2016: Lipids
Sheng-Ping Wang, Dan Zhou, Zuliang Yao, Santhosh Satapati, Ying Chen, Natalie A Daurio, Aleksandr Petrov, Xiaolan Shen, Daniel Metzger, Wu Yin, Andrea R Nawrocki, George J Eiermann, Joyce Hwa, Craig Fancourt, Corey Miller, Kithsiri Herath, Thomas P Roddy, Deborah Slipetz, Mark D Erion, Stephen F Previs, David E Kelley
Aberrant regulation of glucose production makes a critical contribution to the impaired glycemic control that is observed in Type 2 diabetes. Although isotopic tracer methods have proven to be informative in quantifying the magnitude of such alterations, it is presumed that one must rely on venous access to administer glucose tracers which therein presents obstacles for the routine application of tracer methods in rodent models. Since intraperitoneal injections are readily used to deliver glucose challenges and/or dose potential therapeutics, we hypothesized that this route could also be used to administer a glucose tracer...
September 20, 2016: American Journal of Physiology. Endocrinology and Metabolism
Meredith G Clayden, Gretchen L Lescord, Karen A Kidd, Xiaowa Wang, Derek C G Muir, Nelson J O'Driscoll
Nitrogen and carbon stable isotopes (δ(15) N, δ (13) C) are commonly used to understand mercury (Hg) bioaccumulation and biomagnification in freshwater food webs. Though sulfur isotopes (δ (34) S) can distinguish between energy sources from the water column (aqueous sulfate) versus sediments to freshwater organisms, little is known about whether δ (34) S can help interpret variable Hg concentrations in aquatic species or food webs. In this study, 7 acidic lakes in Kejimkujik National Park, NS, Canada, were sampled for biota, water, and sediments in 2009 and 2010...
September 20, 2016: Environmental Toxicology and Chemistry
Amalie Thit, Tina Ramskov, Marie-Noële Croteau, Henriette Selck
The use and likely incidental release of metal nanoparticles (NPs) is steadily increasing. Despite the increasing amount of published literature on metal NP toxicity in the aquatic environment, very little is known about the biological fate of NPs after sediment exposures. Here, we compare the bioavailability and subcellular distribution of copper oxide (CuO) NPs and aqueous Cu (Cu-Aq) in the sediment-dwelling worm Lumbriculus variegatus. Ten days (d) sediment exposure resulted in marginal Cu bioaccumulation in L...
August 31, 2016: Aquatic Toxicology
Sabina Paglialunga, Clayton A Dehn
Non-alcoholic fatty liver disease (NAFLD) is heralded as the next big global epidemic. Hepatic de novo lipogenesis (DNL), the synthesis of new fatty acids from non-lipid sources, is thought to play a pivotal role in the development of NAFLD. While there is currently no NAFLD-specific therapeutic agent available, pharmaceutical drugs aimed at reducing hepatic fat accretion may prove to be a powerful ally in the treatment and management of this disease. With a focus on NAFLD, the present review summarizes current techniques examining DNL from a clinical perspective, and describes the merits and limitations of three commonly used assays; stable-label isotope tracer studies, fatty acid indexes and indirect calorimetry as non-invasive measures of hepatic DNL...
2016: Lipids in Health and Disease
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