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isotopic tracer method

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
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
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
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
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
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
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
Maria Kogadeeva, Nicola Zamboni
Metabolic fluxes are a cornerstone of cellular physiology that emerge from a complex interplay of enzymes, carriers, and nutrients. The experimental assessment of in vivo intracellular fluxes using stable isotopic tracers is essential if we are to understand metabolic function and regulation. Flux estimation based on 13C or 2H labeling relies on complex simulation and iterative fitting; processes that necessitate a level of expertise that ordinarily preclude the non-expert user. To overcome this, we have developed SUMOFLUX, a methodology that is broadly applicable to the targeted analysis of 13C-metabolic fluxes...
September 2016: PLoS Computational Biology
Shengsheng Xu, Igor A Kaltashov
Haptoglobin (Hp) is a plasma glycoprotein that generates significant interest in the drug delivery community because of its potential for delivery of antiretroviral medicines with high selectivity to macrophages and monocytes, the latent reservoirs of human immunodeficiency virus. As is the case with other therapies that exploit transport networks for targeted drug delivery, the success of the design and optimization of Hp-based therapies will critically depend on the ability to accurately localize and quantitate Hp-drug conjugates on the varying and unpredictable background of endogenous proteins having identical structure...
September 12, 2016: Journal of the American Society for Mass Spectrometry
Daniel A Frick, Jan A Schuessler, Friedhelm von Blanckenburg
Stable metal (e.g. Li, Mg, Ca, Fe, Cu, Zn, and Mo) and metalloid (B, Si, Ge) isotope ratio systems have emerged as geochemical tracers to fingerprint distinct physicochemical reactions. These systems are relevant to many Earth Science questions. The benefit of in situ microscale analysis using laser ablation (LA) over bulk sample analysis is to use the spatial context of different phases in the solid sample to disclose the processes that govern their chemical and isotopic compositions. However, there is a lack of in situ analytical routines to obtain a samples' stable isotope ratio together with its chemical composition...
September 28, 2016: Analytica Chimica Acta
Florian C Maier, Julia Schmitt, Andreas Maurer, Walter Ehrlichmann, Gerald Reischl, Konstantin Nikolaou, Rupert Handgretinger, Bernd J Pichler, Wolfgang M Thaiss
Antibody-based therapies gain momentum in clinical therapy, thus the need for accurate imaging modalities with respect to target identification and therapy monitoring are of increasing relevance. Cerenkov luminescence imaging (CLI) are a novel method detecting charged particles emitted during radioactive decay with optical imaging. Here, we compare Position Emission Tomography (PET) with CLI in a multimodal imaging study aiming at the fast and efficient screening of monoclonal antibodies (mAb) designated for targeting of the neuroblastoma-characteristic epitope disialoganglioside GD2...
September 1, 2016: Oncotarget
Christine Hellmann, Katherine G Rascher, Jens Oldeland, Christiane Werner
Environmental heterogeneity and plant-plant interactions are key factors shaping plant communities. However, the spatial dimension of plant-plant interactions has seldom been addressed in field studies. This is at least partially rooted in a lack of methods that can accurately resolve functional processes in a spatially explicit manner. Isoscapes, that is, spatially explicit representations of stable isotope data, provide a versatile means to trace functional changes on spatial scales, for example, related to N-cycling (foliar δ(15)N) and water use efficiency (WUEi, foliar δ(13)C)...
September 1, 2016: Tree Physiology
Simon-Pierre Gravel, Daina Avizonis, Julie St-Pierre
The tumor microenvironment is a complex and heterogeneous milieu in which cancer cells undergo metabolic reprogramming to fuel their growth. Cancer cell lines grown in vitro using traditional culture methods represent key experimental models to gain a mechanistic understanding of tumor biology. This protocol describes the use of gas chromatography-mass spectrometry (GC-MS) to assess metabolic changes in cancer cells grown under varied levels of oxygen and nutrients that may better mimic the tumor microenvironment...
2016: Methods in Molecular Biology
Sjaam Jainandunsing, Joram N I van Miert, Trinet Rietveld, J L Darcos Wattimena, Eric J G Sijbrands, Felix W M de Rooij
AIMS: In vitro, beta cells immediately secrete stored but readily releasable insulin in response to a rise of glucose. During a prolonged insulin response, this is followed by newly synthesized insulin. Our aim was to develop an in vivo test to determine the ratio between readily available and newly synthesized insulin after a stimulus in humans by labelling newly synthesized insulin. METHODS: A stable isotope tracer of 1.0 g (13)C leucine with C-peptide as target peptide was administered 45 min prior to 75 g glucose load of a frequently blood sampled 210-min oral glucose tolerance test (OGTT)...
August 23, 2016: Acta Diabetologica
Inge van der Kroon, Lieke Joosten, Berthold A Nock, Theodosia Maina, Otto C Boerman, Maarten Brom, Martin Gotthardt
OBJECTIVE: Accurate assessment of the (111)In-exendin-3 uptake within the pancreas requires exact delineation of the pancreas, which is highly challenging by MRI and CT in rodents. In this study, the pancreatic tracer (99m)Tc-demobesin-4 was evaluated for accurate delineation of the pancreas to be able to accurately quantify (111)In-exendin-3 uptake within the pancreas. METHODS: Healthy and alloxan-induced diabetic Brown Norway rats were injected with the pancreatic tracer (99m)Tc-demobesin-4 ([(99m)Tc-N4-Pro(1),Tyr(4),Nle(14)]bombesin) and the beta cell tracer (111)In-exendin-3 ([(111)In-DTPA-Lys(40)]exendin-3)...
October 3, 2016: Molecular Pharmaceutics
Dmitry Y Litvinov, Eugeny V Savushkin, Evdokiya A Garaeva, Alexander D Dergunov
BACKGROUND: Cholesterol efflux as a key event in reverse cholesterol transport (RCT) is considered now as both diagnostic tool and a promising target for treatment of atherosclerosis. Radioactive in vitro cholesterol efflux assay (CEA) is the gold standard for determination of efflux at cellular level. Fluorescent tracers and stable isotope-labeled cholesterol gradually come into use as convenient tools for non-radioactive CEAs. RESULTS: We review the use of various tracer-based and tracer-free methods for CEAs and for measuring RCT with focus on macrophage-specific cholesterol efflux...
August 8, 2016: Current Medicinal Chemistry
Steven H Liang, Neil Vasdev
The logic of total synthesis transformed a stagnant state of medicinal and synthetic organic chemistry when there was a paucity of methods and reagents to synthesize drug molecules and/or natural products. Molecular imaging by positron emission tomography (PET) is now experiencing a renaissance in the way radiopharmaceuticals for molecular imaging are synthesized, however, a paradigm shift is desperately needed in the discovery pipeline to accelerate in vivo imaging studies. A significant challenge in radiochemistry is the limited choice of labeled reagents (or building blocks) available for the synthesis of novel radiopharmaceuticals with the most commonly used short-lived radionuclides carbon-11 ((11)C; half-life ~20 minutes) and fluorine-18 ((18)F; half-life ~2 hours)...
September 2015: Australian Journal of Chemistry
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