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https://www.readbyqxmd.com/read/27906461/measurement-of-intestinal-and-peripheral-cholesterol-fluxes-by-a-dual-tracer-balance-method
#1
Onne A H O Ronda, Theo H van Dijk, H J Verkade, Albert K Groen
Long-term elevated plasma cholesterol levels put individuals at risk for developing atherosclerosis. Plasma cholesterol levels are determined by the balance between cholesterol input and output fluxes. Here we describe in detail the methodology to determine the different cholesterol fluxes in mice. The percentage of absorbed cholesterol is calculated from a stable isotope-based double-label method. Cholesterol synthesis is calculated from MIDA after (13) C-acetate enrichment. Cholesterol is removed from the body via the feces...
December 1, 2016: Current Protocols in Mouse Biology
https://www.readbyqxmd.com/read/27896775/uplc-ms-ms-determination-of-deuterated-25-hydroxyvitamin-d-d3-25ohd3-and-other-vitamin-d-metabolites-for-the-measurement-of-25ohd-half-life
#2
Shima Assar, Inez Schoenmakers, Albert Koulman, Ann Prentice, Kerry S Jones
Plasma 25-hydroxyvitamin D (25OHD) half-life (25OHDt 1/2) is a dynamic marker of vitamin D metabolism that can be used to assess vitamin D expenditure and help inform vitamin D requirements. Our group recently established an approach to determine the 25OHDt 1/2 as an alternative biomarker of 25OHD expenditure in humans. The approach uses a small oral dose of stable isotope labeled 25OHD3 [3-(2)H-25OHD(3) (6,19,19-d3)] (d3-25OHD3) (tracer), which is distinguishable from endogenous 25OHD by liquid chromatography tandem-mass spectrometry (LC-MS/MS)...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/27884075/srm-based-measurements-of-proprotein-convertase-subtilisin-kexin-type-9-and-lipoprotein-a-kinetics-in-nonhuman-primate-serum
#3
Fang Xie, Maurice G Emery, John P Gibbs, Dan A Rock, Brooke M Rock
AIM: PCSK9 and Lp(a) have been identified as potential biomarkers for cardiovascular disease. The ability to measure protein turnover rates will provide insights into the dynamic properties of these proteins and lead to better understanding of their biological roles. We aimed to implement the stable isotope-labeled tracers ([(2)H3]-leucine) and develop a novel LC-selected reaction monitoring (SRM) mass spectrometry (MS) method to study the kinetics of PCSK9 and Lp(a). RESULTS: A sensitive method using immunoaffinity enrichment coupled with LC-SRM MS was developed to measure the production and degradation rates of PCSK9 and Lp(a) in naive nonhuman primate serum...
December 2016: Bioanalysis
https://www.readbyqxmd.com/read/27843065/measuring-radon-222-in-soil-gas-with-high-spatial-and-temporal-resolution
#4
Darren Huxtable, David Read, George Shaw
In order to exploit (222)Rn as a naturally-occurring tracer in soils we need to sample and measure radon isotopes in soil gas with high spatial and temporal resolution, without disturbing in situ activity concentrations and fluxes. Minimisation of sample volume is key to improving the resolution with which soil gas can be sampled; an analytical method is then needed which can measure radon with appropriate detection limits and precision for soil gas tracer studies. We have designed a soil gas probe with minimal internal dead volume to allow us to sample soil gas volumes of 45 cm(3)...
November 11, 2016: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/27832302/rapid-ion-exchange-matrix-removal-for-a-decrease-of-detection-limits-in-the-analysis-of-salt-rich-reservoir-waters-for-fluorobenzoic-acids-by-liquid-chromatography-coupled-with-tandem-mass-spectrometry
#5
Paweł Kubica, Véronique Vacchina, Tomasz Wasilewski, Stéphanie Reynaud, Joanna Szpunar, Ryszard Lobinski
A matrix removal procedure with ion-exchange resin prior to analysis for 18 fluorinated benzoic acids (FBAs) tracers in saline (>25% salt) reservoir water was optimized. The elimination of >98% of salt and the simultaneous matrix sample cleanup allowed the direct analysis using the supernatant by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). This resulted in a gain in detection limits for most of the tracers in comparison with the reference method (direct analysis after minimum required dilution)...
November 10, 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27766703/a-simple-and-reliable-anion-exchange-resin-method-for-sulfate-extraction-and-purification-suitable-for-multiple-o-and-s-isotope-measurements
#6
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
https://www.readbyqxmd.com/read/27761615/a-strategy-for-simultaneous-determination-of-fatty-acid-composition-fatty-acid-position-and-position-specific-isotope-contents-in-triacylglycerol-matrices-by-13-c-nmr
#7
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
https://www.readbyqxmd.com/read/27759065/effect-of-phytase-on-zinc-absorption-from-a-millet-based-porridge-fed-to-young-burkinabe-children
#8
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
https://www.readbyqxmd.com/read/27754354/analysis-of-mammalian-cell-proliferation-and-macromolecule-synthesis-using-deuterated-water-and-gas-chromatography-mass-spectrometry
#9
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
https://www.readbyqxmd.com/read/27744602/zinc-fractional-absorption-from-a-representative-diet-in-young-chinese-men-and-women-of-the-shandong-rural-region
#10
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
https://www.readbyqxmd.com/read/27722818/triennial-changes-in-groundwater-quality-in-aquifers-used-for-public-supply-in-california-utility-as-indicators-of-temporal-trends
#11
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...
December 0: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/27706078/strategies-for-extending-metabolomics-studies-with-stable-isotope-labelling-and-fluxomics
#12
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
https://www.readbyqxmd.com/read/27683870/retinol-isotope-dilution-is-applied-during-restriction-of-vitamin-a-intake-to-predict-individual-subject-total-body-vitamin-a-stores-at-isotopic-equilibrium
#13
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
https://www.readbyqxmd.com/read/27664633/rare-earth-elements-and-87-sr-86-sr-isotopic-characterization-of-indian-basmati-rice-as-potential-tool-for-its-geographical-authenticity
#14
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
https://www.readbyqxmd.com/read/27651111/quantifying-rates-of-glucose-production-in-vivo-following-an-intraperitoneal-tracer-bolus
#15
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, Corin 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...
December 1, 2016: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/27626798/sumoflux-a-generalized-method-for-targeted-13c-metabolic-flux-ratio-analysis
#16
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
https://www.readbyqxmd.com/read/27619921/evaluation-of-gallium-as-a-tracer-of-exogenous-hemoglobin-haptoglobin-complexes-for-targeted-drug-delivery-applications
#17
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
https://www.readbyqxmd.com/read/27619084/development-of-routines-for-simultaneous-in-situ-chemical-composition-and-stable-si-isotope-ratio-analysis-by-femtosecond-laser-ablation-inductively-coupled-plasma-mass-spectrometry
#18
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
https://www.readbyqxmd.com/read/27602580/correlation-between-positron-emission-tomography-and-cerenkov-luminescence-imaging-in-vivo-and-ex-vivo-using-64cu-labeled-antibodies-in-a-neuroblastoma-mouse-model
#19
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
https://www.readbyqxmd.com/read/27587484/isoscapes-resolve-species-specific-spatial-patterns-in-plant-plant-interactions-in-an-invaded-mediterranean-dune-ecosystem
#20
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
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