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https://www.readbyqxmd.com/read/28303165/modeling-framework-for-isotopic-labeling-of-heteronuclear-moieties
#1
Mark I Borkum, Patrick N Reardon, Ronald C Taylor, Nancy G Isern
BACKGROUND: Isotopic labeling is an analytic technique that is used to track the movement of isotopes through reaction networks. In general, the applicability of isotopic labeling techniques is limited to the investigation of reaction networks that consider homonuclear moieties, whose atoms are of one tracer element with two isotopes, distinguished by the presence of one additional neutron. RESULTS: This article presents a reformulation of the modeling framework for isotopic labeling, generalized to arbitrarily large, heteronuclear moieties, arbitrary numbers of isotopic tracer elements, and arbitrary numbers of isotopes per element, distinguished by arbitrary numbers of additional neutrons...
2017: Journal of Cheminformatics
https://www.readbyqxmd.com/read/28302981/studies-on-isotope-ratio-measurement-of-cl-by-inductively-coupled-plasma-triple-quad-mass-spectrometry
#2
Masaki Ohata, Yanbei Zhu, Naoko Nonose
Fundamental studies on isotope ratio measurement of Cl were carried out using inductively coupled plasma triple-quad mass spectrometry (ICP-MS/MS) and the analytical performance obtained was compared to that obtained by ICP sector field mass spectrometer (ICP-SFMS). Though the polyatomic ion interferences of (16)O(18)O(1)H and (36)Ar(1)H with respect to (35)Cl and (37)Cl, respectively, made a negative effect on the accuracy and the precision for isotope ratio measurements of Cl, the ICP-SFMS could eliminate these interferences by medium mass resolution mode (m/Δm = 4000) and achieved the isotope ratio measurements with 0...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
https://www.readbyqxmd.com/read/28294174/docosahexaenoic-acid-enrichment-in-nafld-is-associated-with-improvements-in-hepatic-metabolism-and-hepatic-insulin-sensitivity-a-pilot-study
#3
L Hodson, L Bhatia, E Scorletti, D E Smith, N C Jackson, F Shojaee-Moradie, M Umpleby, P C Calder, C D Byrne
BACKGROUND/OBJECTIVE: Treatment of subjects with non-alcoholic fatty liver disease (NAFLD) with omega-3 polyunsaturated fatty acids (FAs) suggests high levels of docosahexaenoic acid (DHA) tissue enrichment decrease liver fat content. We assessed whether changes in erythrocyte DHA enrichment (as a surrogate marker of changes in tissue enrichment) were associated with alterations in hepatic de novo lipogenesis (DNL), postprandial FA partitioning and hepatic and peripheral insulin sensitivity in a sub-study of the WELCOME trial (Wessex Evaluation of fatty Liver and Cardiovascular markers in NAFLD (non-alcoholic fatty liver disease) with OMacor thErapy)...
March 15, 2017: European Journal of Clinical Nutrition
https://www.readbyqxmd.com/read/28289709/imaging-mass-spectrometry-demonstrates-age-related-decline-in-human-adipose-plasticity
#4
Christelle Guillermier, Pouneh K Fazeli, Soomin Kim, Mingyue Lun, Jonah P Zuflacht, Jessica Milian, Hang Lee, Hugues Francois-Saint-Cyr, Francois Horreard, David Larson, Evan D Rosen, Richard T Lee, Claude P Lechene, Matthew L Steinhauser
Quantification of stable isotope tracers has revealed the dynamic state of living tissues. A new form of imaging mass spectrometry quantifies isotope ratios in domains much smaller than a cubic micron, enabling measurement of cell turnover and metabolism with stable isotope tracers at the single-cell level with a methodology we refer to as multi-isotope imaging mass spectrometry. In a first-in-human study, we utilize stable isotope tracers of DNA synthesis and de novo lipogenesis to prospectively measure cell birth and adipocyte lipid turnover...
March 9, 2017: JCI Insight
https://www.readbyqxmd.com/read/28285086/rapid-determination-of-radium-224-226-in-seawater-sample-by-alpha-spectrometry
#5
Lijuan Song, Yonggang Yang, Maoyi Luo, Yan Ma, Xiongxin Dai
A new radiochemical separation method has been developed for rapid determination of alpha-emitting radium isotopes in seawater samples. This method can be applied for the measurement of (226)Ra in seawater samples when (224)Ra is used as tracer for chemical recovery correction. Likewise, (226)Ra can also be added as tracer for the determination of (224)Ra in seawater sample. In the method, radium is first pre-concentrated with hydrous titanium oxide (HTiO) and is purified by combined anion/cation exchange column chromatographic separation...
March 8, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28272836/mapping-carbon-fate-during-bleaching-in-a-model-cnidarian-symbiosis-the-application-of-13-c-metabolomics
#6
Katie E Hillyer, Daniel A Dias, Adrian Lutz, Ute Roessner, Simon K Davy
Coral bleaching is a major threat to the persistence of coral reefs. Yet we lack detailed knowledge of the metabolic interactions that determine symbiosis function and bleaching-induced change. We mapped autotrophic carbon fate within the free metabolite pools of both partners of a model cnidarian-dinoflagellate symbiosis (Aiptasia-Symbiodinium) during exposure to thermal stress via the stable isotope tracer ((13) C bicarbonate), coupled to GC-MS. Symbiont photodamage and pronounced bleaching coincided with substantial increases in the turnover of non(13) C-labelled pools in the dinoflagellate (lipid and starch store catabolism)...
March 8, 2017: New Phytologist
https://www.readbyqxmd.com/read/28270442/a-four-compartments-compartmental-model-to-assess-net-whole-body-protein-breakdown-using-a-pulse-of-phenylalanine-and-tyrosine-stable-isotopes-in-humans
#7
Alvise Mason, Marielle Pkj Engelen, Ivan Ivanov, Gianna M Toffolo, Nicolaas E P Deutz
The stable isotopes of Phenylalanine (Phe) and Tyrosine (Tyr) are often used to study whole body protein metabolism in humans. Non-compartmental approaches give limited physiological insight in the compartmental characteristics. We therefore developed a mathematical model of Phe/Tyr metabolism to describe protein fluxes using stable tracer dynamic data in plasma following iv bolus of L-[ring-(13)C6]-Phe and L-[ring-(2)H4]-Tyr in healthy subjects. The model consists of four compartments describing Phe/Tyr kinetics...
March 7, 2017: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28266611/important-fossil-source-contribution-to-brown-carbon-in-beijing-during-winter
#8
Caiqing Yan, Mei Zheng, Carme Bosch, August Andersson, Yury Desyaterik, Amy P Sullivan, Jeffrey L Collett, Bin Zhao, Shuxiao Wang, Kebin He, Örjan Gustafsson
Organic aerosol (OA) constitutes a substantial fraction of fine particles and affects both human health and climate. It is becoming clear that OA absorbs light substantially (hence termed Brown Carbon, BrC), adding uncertainties to global aerosol radiative forcing estimations. The few current radiative-transfer and chemical-transport models that include BrC primarily consider sources from biogenic and biomass combustion. However, radiocarbon fingerprinting here clearly indicates that light-absorbing organic carbon in winter Beijing, the capital of China, is mainly due to fossil sources, which contribute the largest part to organic carbon (OC, 67 ± 3%) and its sub-constituents (water-soluble OC, WSOC: 54 ± 4%, and water-insoluble OC, WIOC: 73 ± 3%)...
March 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28263717/nmr-based-stable-isotope-resolved-metabolomics-in-systems-biochemistry
#9
Andrew N Lane, Teresa W-M Fan
Metabolism is the basic activity of live cells, and monitoring the metabolic state provides a dynamic picture of the cells or tissues, and how they respond to external changes, for in disease or treatment with drugs. NMR is an extremely versatile analytical tool that can be applied to a wide range of biochemical problems. Despite its modest sensitivity its versatility make it an ideal tool for analyzing biochemical dynamics both in vitro and in vivo, especially when coupled with its isotope editing capabilities, from which isotope distributions can be readily determined...
March 2, 2017: Archives of Biochemistry and Biophysics
https://www.readbyqxmd.com/read/28255355/hybrid-imaging-labels-providing-the-link-between-mass-spectrometry-based-molecular-pathology-and-theranostics
#10
Tessa Buckle, Steffen van der Wal, Stijn J M van Malderen, Larissa Müller, Joeri Kuil, Vincent van Unen, Ruud J B Peters, Margaretha E M van Bemmel, Liam A McDonnell, Aldrik H Velders, Frits Koning, Frank Vanhaeke, Fijs W B van Leeuwen
BACKGROUND: Development of theranostic concepts that include inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) imaging can be hindered by the lack of a direct comparison to more standardly used methods for in vitro and in vivo evaluation; e.g. fluorescence or nuclear medicine. In this study a bimodal (or rather, hybrid) tracer that contains both a fluorescent dye and a chelate was used to evaluate the existence of a direct link between mass spectrometry (MS) and in vitro and in vivo molecular imaging findings using fluorescence and radioisotopes...
2017: Theranostics
https://www.readbyqxmd.com/read/28249106/rapid-quantification-and-isotopic-analysis-of-dissolved-sulfur-species
#11
Derek A Smith, Alex L Sessions, Nathan Dalleska, Victoria J Orphan
RATIONALE: Dissolved sulfur species are of significant interest, both as important substrates for microbial activities and as key intermediaries in biogeochemical cycles. Species of intermediate oxidation state such as sulfite, thiosulfate, and thiols are of particular interest but are notoriously difficult to analyze, because of low concentrations and rapid oxidation during storage and analysis. METHODS: Dissolved sulfur species are reacted with monobromobimane which yields a fluorescent bimane derivative that is stable to oxidation...
March 1, 2017: Rapid Communications in Mass Spectrometry: RCM
https://www.readbyqxmd.com/read/28245099/hiv-infection-does-not-prevent-the-metabolic-benefits-of-diet-induced-weight-loss-in-women-with-obesity
#12
Dominic N Reeds, Terri A Pietka, Kevin E Yarasheski, W Todd Cade, Bruce W Patterson, Adewole Okunade, Nada A Abumrad, Samuel Klein
OBJECTIVE: To test the hypothesis that HIV infection impairs the beneficial effects of weight loss on insulin sensitivity, adipose tissue inflammation, and endoplasmic reticulum (ER) stress. METHODS: A prospective clinical trial evaluated the effects of moderate diet-induced weight loss on body composition, metabolic function, and adipose tissue biology in women with obesity who were HIV-seronegative (HIV-) or HIV-positive (HIV+). Body composition, multiorgan insulin sensitivity (assessed by using a two-stage hyperinsulinemic-euglycemic clamp procedure with stable isotopically labeled tracer infusions), and adipose tissue expression of markers of inflammation, autophagy, and ER stress were evaluated in 8 HIV- and 20 HIV+ women with obesity before and after diet-induced weight loss of 6% to 8%...
February 28, 2017: Obesity
https://www.readbyqxmd.com/read/28241817/berberine-improves-glucogenesis-and-lipid-metabolism-in-nonalcoholic-fatty-liver-disease
#13
Li Zhao, Zhen Cang, Honglin Sun, Xiaomin Nie, Ningjian Wang, Yingli Lu
BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is considered a critical hepatic manifestation of metabolic syndrome. Berberine (BBR) exerts anti-hyperglycemic and anti-dyslipidemic effects and can also ameliorate NAFLD. Thus, BBR might exert its therapeutic effect on NAFLD by improving glucolipid metabolism. Here, we investigated the aspects and extent to which glucolipid metabolism were affected by BBR in rats with NAFLD. METHODS: Three groups of Sprague-Dawley rats were studied: a control group (n = 6) fed a normal chow diet and a NAFLD group (n = 6) and a NAFLD + BBR group (n = 6) fed a high-fat diet...
February 28, 2017: BMC Endocrine Disorders
https://www.readbyqxmd.com/read/28220994/positional-enrichment-by-proton-analysis-pepa-a-one-dimensional-1-h-nmr-approach-for-13-c-stable-isotope-tracer-studies-in-metabolomics
#14
Maria Vinaixa, Miguel A Rodríguez, Suvi Aivio, Jordi Capellades, Josep Gómez, Nicolau Canyellas, Travis H Stracker, Oscar Yanes
A novel metabolomics approach for NMR-based stable isotope tracer studies called PEPA is presented, and its performance validated using human cancer cells. PEPA detects the position of carbon label in isotopically enriched metabolites and quantifies fractional enrichment by indirect determination of (13) C-satellite peaks using 1D-(1) H-NMR spectra. In comparison with (13) C-NMR, TOCSY and HSQC, PEPA improves sensitivity, accelerates the elucidation of (13) C positions in labeled metabolites and the quantification of the percentage of stable isotope enrichment...
February 21, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28213127/quantitation-of-lead-210-210-pb-using-lead-203-203-pb-as-a-massless-yield-tracer
#15
D May, A N Nelson, M K Schultz
Determination of Pb-210 ((210)Pb) in aqueous solution is a common radioanalytical challenge in environmental science. Widely used methods for undertaking these analyses (e.g., ASTM D7535) rely on the use of stable lead (Pb) as a yield tracer that takes into account losses of (210)Pb that inevitably occur during elemental/radiochemical separations of the procedures. Although effective, these methods introduce technical challenges that can be difficult to track and potentially introduce uncertainty that can be difficult to quantify...
February 14, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28212026/isotope-tracers-to-study-the-environmental-fate-and-bioaccumulation-of-metal-containing-engineered-nanoparticles-techniques-and-applications
#16
Yongguang Yin, Zhiqiang Tan, Ligang Hu, Sujuan Yu, Jingfu Liu, Guibin Jiang
The rapidly growing applicability of metal-containing engineered nanoparticles (MENPs) has made their environmental fate, biouptake, and transformation important research topics. However, considering the relatively low concentration of MENPs and the high concentration of background metals in the environment and in organisms, tracking the fate of MENPs in environment-related scenarios remains a challenge. Intrinsic labeling of MENPs with radioactive or stable isotopes is a useful tool for the highly sensitive and selective detection of MENPs in the environment and organisms, thus enabling tracing of their transformation, uptake, distribution, and clearance...
February 17, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/28205600/non-reliance-of-metazoans-on-stromatolite-forming-microbial-mats-as-a-food-resource
#17
Gavin M Rishworth, Renzo Perissinotto, Matthew S Bird, Nadine A Strydom, Nasreen Peer, Nelson A F Miranda, Jacqueline L Raw
Grazing and burrowing organisms usually homogenise microalgal mats that form on benthic sediments of many aquatic ecosystems. In the absence of this disruption, microalgal mats can accrete laminated deposits (stromatolites). Stromatolites are rare in modern coastal ecosystems, but persist at locations where metazoans are largely excluded. This study aimed to assess the trophic structure at stromatolite locations where metazoans co-occur, to determine the grazing influence exerted by the metazoans on the stromatolite-forming microalgae (cyanobacteria and diatoms)...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28205581/pathways-of-n-removal-and-n2o-emission-from-a-one-stage-autotrophic-n-removal-process-under-anaerobic-conditions
#18
Kai Li, Fang Fang, Han Wang, Chao Wang, Youpeng Chen, Jinsong Guo, Xixi Wang, Fuyang Jiang
To investigate the pathways of nitrogen (N) removal and N2O emission in a one-stage autotrophic N removal process during the non-aeration phase, biofilm from an intermittent aeration sequencing batch biofilm reactor (SBBR) and organic carbon-free synthetic wastewater were applied to two groups of lab-scale batch experiments in anaerobic conditions using a (15)N isotopic tracer and specific inhibitors, respectively. Then, the microbial composition of the biofilm was analysed using high-throughput sequencing...
February 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28196754/determination-of-groundwater-recharge-mechanism-in-the-deep-loessial-unsaturated-zone-by-environmental-tracers
#19
Zhi Li, Xi Chen, Wenzhao Liu, Bingcheng Si
Studying the groundwater recharge mechanism in regions with thick unsaturated zone can greatly improve our understanding of hydrological processes since these regions have complex groundwater processes. This study attempted to discuss the groundwater recharge in a region covered by loess over 130m deep in China's Loess Plateau. The water stable isotope, tritium and chloride in precipitation, groundwater and soil water were determined and used as inputs of mass balance methods. The tracer technique is found to be applicable and effective this region with thick unsaturated zone...
May 15, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28195703/mass-spectrometric-determination-of-uranium-and-thorium-in-high-radiopurity-polymers-using-ultra-low-background-electroformed-copper-crucibles-for-dry-ashing
#20
Isaac J Arnquist, Eric J Hoppe, Mary Bliss, Jay W Grate
A rapid new method for determining the U and Th mass concentrations in high radiopurity plastics is described, consisting of (1) dry ashing the plastic sample and tracers in low mass crucibles made of ultra low background electroformed copper (ULB EF-Cu) foil cut and folded into boats, (2) dissolving both the ash and the boat in acid, (3) performing a column separation to remove copper, and (4) determining the elements of interest by isotope dilution mass spectrometry. This method was demonstrated on both unfluorinated and fluorinated plastics, demonstrating high tracer recoveries and detection limits to pg/g (i...
February 24, 2017: Analytical Chemistry
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