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https://www.readbyqxmd.com/read/28527806/endogenous-synthesis-of-milk-oleic-acid-in-dairy-ewes-in-vivo-measurement-using-13-c-labeled-stearic-acid
#1
P G Toral, P Frutos, D Carreño, G Hervás
The use of stable isotopes is a reliable and risk-free alternative to radioactive tracers for directly examining in vivo fatty acid (FA) metabolism. However, very limited information is available in ruminants, and none is available in sheep. Therefore, we conducted an experiment in dairy ewes to determine, for the first time in this species, the uptake, Δ(9)-desaturation, and secretion of (13)C-labeled stearic acid (SA) into milk with the aim of measuring in vivo endogenous synthesis of milk oleic acid (OA) and stearoyl-CoA desaturase activity...
May 17, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28527646/high-dose-amino-acid-administration-achieves-an-anabolic-response-in-type-2-diabetic-patients-that-is-independent-of-glycaemic-control-a-randomized-clinical-trial
#2
Chelsia Gillis, Patricia S Roque, Jürgen Bläss, Albert Urwyler, Harald Schepperle, Guido Kunz, Thomas Peters, Thomas Schricker, Linda Wykes, Andrea Kopp Lugli
BACKGROUND & AIMS: Surgical stress provokes protein catabolism and hyperglycaemia that is enhanced in patients with type 2 diabetes (T2DM), and increases perioperative morbidity. This study hypothesized that perioperative administration of high dose intravenous (IV) amino acids (AA) will augment protein balance in T2DM patients receiving tight plasma glucose control via continuous IV insulin compared to standard plasma glucose control via subcutaneous (SC) insulin sliding scale. METHODS: Eighteen patients with well-controlled T2DM (HbA1C% < 7...
May 3, 2017: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
https://www.readbyqxmd.com/read/28522731/effect-of-metformin-on-bioactive-lipid-metabolism-in-insulin-resistant-muscle
#3
Piotr Zabielski, Marta Chacinska, Karol Charkiewicz, Marcin Baranowski, Jan Gorski, Agnieszka U Blachnio-Zabielska
Intramuscular accumulation of bioactive lipids leads to insulin resistance and type 2 diabetes (T2D). There is lack of consensus concerning which of the lipid mediators has the greatest impact on muscle insulin action in vivo Our aim was to elucidate the effects of high-fat diet (HFD) and metformin (Met) on skeletal muscle bioactive lipid accumulation and insulin resistance (IR) in rats. We employed a [U-(13)C]palmitate isotope tracer and mass spectrometry to measure the content and fractional synthesis rate (FSR) of intramuscular long-chain acyl-CoA (LCACoA), diacylglycerols (DAG) and ceramide (Cer)...
June 2017: Journal of Endocrinology
https://www.readbyqxmd.com/read/28516958/the-origin-and-degassing-history-of-the-earth-s-atmosphere-revealed-by-archean-xenon
#4
Guillaume Avice, Bernard Marty, Ray Burgess
Xenon (Xe) is an exceptional tracer for investigating the origin and fate of volatile elements on Earth. The initial isotopic composition of atmospheric Xe remains unknown, as do the mechanisms involved in its depletion and isotopic fractionation compared with other reservoirs in the solar system. Here we present high precision analyses of noble gases trapped in fluid inclusions of Archean quartz (Barberton, South Africa) that reveal the isotopic composition of the paleo-atmosphere at ≈3.3 Ga. The Archean atmospheric Xe is mass-dependently fractionated by 12...
May 18, 2017: Nature Communications
https://www.readbyqxmd.com/read/28515163/assessment-of-nitric-oxide-production-in-mitochondrial-encephalomyopathy-lactic-acidosis-and-stroke-like-episodes-syndrome-with-the-use-of-a-stable-isotope-tracer-infusion-technique
#5
REVIEW
Ayman W El-Hattab, Farook Jahoor
Mitochondrial disorders result from dysfunctional mitochondria that are unable to generate sufficient energy to meet the needs of various organs. Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is one of the most frequent maternally inherited mitochondrial disorders. There is growing evidence that nitric oxide (NO) deficiency occurs in MELAS syndrome and results in impaired blood perfusion that contributes significantly to several complications in this disease. NO is synthesized from arginine by NO synthase, which catalyzes the conversion of arginine to NO and citrulline...
May 17, 2017: Journal of Nutrition
https://www.readbyqxmd.com/read/28514443/cancer-progression-by-reprogrammed-bcaa-metabolism-in-myeloid-leukaemia
#6
Ayuna Hattori, Makoto Tsunoda, Takaaki Konuma, Masayuki Kobayashi, Tamas Nagy, John Glushka, Fariba Tayyari, Daniel McSkimming, Natarajan Kannan, Arinobu Tojo, Arthur S Edison, Takahiro Ito
Reprogrammed cellular metabolism is a common characteristic observed in various cancers. However, whether metabolic changes directly regulate cancer development and progression remains poorly understood. Here we show that BCAT1, a cytosolic aminotransferase for branched-chain amino acids (BCAAs), is aberrantly activated and functionally required for chronic myeloid leukaemia (CML) in humans and in mouse models of CML. BCAT1 is upregulated during progression of CML and promotes BCAA production in leukaemia cells by aminating the branched-chain keto acids...
May 17, 2017: Nature
https://www.readbyqxmd.com/read/28500352/whole-mantle-convection-with-tectonic-plates-preserves-long-term-global-patterns-of-upper-mantle-geochemistry
#7
T L Barry, J H Davies, M Wolstencroft, I L Millar, Z Zhao, P Jian, I Safonova, M Price
The evolution of the planetary interior during plate tectonics is controlled by slow convection within the mantle. Global-scale geochemical differences across the upper mantle are known, but how they are preserved during convection has not been adequately explained. We demonstrate that the geographic patterns of chemical variations around the Earth's mantle endure as a direct result of whole-mantle convection within largely isolated cells defined by subducting plates. New 3D spherical numerical models embedded with the latest geological paleo-tectonic reconstructions and ground-truthed with new Hf-Nd isotope data, suggest that uppermost mantle at one location (e...
May 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28495844/molecular-imaging-of-postprandial-metabolism
#8
Vera B Schrauwen-Hinderling, Andre C Carpentier
Disordered postprandial metabolism of energy substrates is one of the main defining features of prediabetes and contributes to the development of several chronic diseases associated with obesity such as type 2 diabetes and cardiovascular diseases. Postprandial energy metabolism has been studied using classical isotopic tracer approaches that are limited by the poor access to splanchnic metabolism and the highly dynamic and complex exchanges of energy substrates involving multiple organs and systems. Advances in non-invasive molecular imaging modalities such as positron emission tomography (PET) and magnetic resonance imaging and spectroscopy (MRI/MRS) have recently allowed important advances in our understanding of postprandial energy metabolism in humans...
May 11, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28484010/erythritol-is-a-pentose-phosphate-pathway-metabolite-and-associated-with-adiposity-gain-in-young-adults
#9
Katie C Hootman, Jean-Pierre Trezzi, Lisa Kraemer, Lindsay S Burwell, Xiangyi Dong, Kristin A Guertin, Christian Jaeger, Patrick J Stover, Karsten Hiller, Patricia A Cassano
Metabolomic markers associated with incident central adiposity gain were investigated in young adults. In a 9-mo prospective study of university freshmen (n = 264). Blood samples and anthropometry measurements were collected in the first 3 d on campus and at the end of the year. Plasma from individuals was pooled by phenotype [incident central adiposity, stable adiposity, baseline hemoglobin A1c (HbA1c) > 5.05%, HbA1c < 4.92%] and assayed using GC-MS, chromatograms were analyzed using MetaboliteDetector software, and normalized metabolite levels were compared using Welch's t test...
May 8, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28471639/metabolically-generated-stable-isotope-labeled-deoxynucleoside-code-for-tracing-dna-n-6-methyladenine-in-human-cells
#10
Baodong Liu, Xiaoling Liu, Weiyi Lai, Hailin Wang
DNA N(6)-methyl-2'-deoxyadenosine (6mdA) is an epigenetic modification in both eukaryotes and bacteria. Here we exploited stable isotope-labeled deoxynucleoside [(15)N5]-2'-deoxyadenosine ([(15)N5]-dA) as an initiation tracer and for the first time developed a metabolically differential tracing code for monitoring DNA 6mdA in human cells. We demonstrate that the initiation tracer [(15)N5]-dA undergoes a specific and efficient adenine deamination reaction leading to the loss the exocyclic amine (15)N, and further utilizes the purine salvage pathway to generate mainly both [(15)N4]-dA and [(15)N4]-2'-deoxyguanosine ([(15)N4]-dG) in mammalian genomes...
May 11, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28470676/acetyl-coa-carboxylase-inhibition-reduces-de-novo-lipogenesis-in-overweight-male-subjects-a-randomized-double-blind-crossover-study
#11
Kathryn Stiede, Wenyan Miao, Heather S Blanchette, Carine Beysen, Geraldine Harriman, H James Harwood, Heather Kelley, Rosana Kapeller, Tess Schmalbach, William F Westlin
NDI-010976, an allosteric inhibitor of acetyl-CoA carboxylases (ACC) ACC1 and ACC2, reduces hepatic de novo lipogenesis (DNL) and favorably affects steatosis, inflammation, and fibrosis in animal models of fatty liver disease. This study was a randomized, double-blind, placebo-controlled, crossover trial evaluating the pharmacodynamic effects of a single oral dose of NDI-010976 on hepatic DNL in overweight and/or obese, but otherwise healthy, adult male subjects. Subjects were randomized to receive either NDI-010976 (20, 50, or 200 mg) or matching placebo in Period 1, followed by the alternate treatment in Period 2, and hepatic lipogenesis was stimulated with oral fructose administration...
May 3, 2017: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
https://www.readbyqxmd.com/read/28467082/novel-method-for-nitrogen-isotopic-analysis-of-soil-emitted-nitric-oxide
#12
Zhongjie Yu, Emily M Elliott
The global inventory of NOx (NOx = NO + NO2) emissions is poorly constrained, with a large portion of the uncertainty attributed to soil NO emissions that result from soil abiotic and microbial processes. While natural abundance stable N isotopes (δ(15)N) in various soil N-containing compounds have proven to be a robust tracer of soil N cycling, soil δ(15)N-NO is rarely quantified due to the measurement difficulties. Here, we present a new method that collects soil-emitted NO through NO conversion to NO2 in excess ozone (O3) and subsequent NO2 collection in a 20% triethanolamine (TEA) solution as nitrite and nitrate for δ(15)N analysis using the denitrifier method...
May 12, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28458223/chemical-contaminants-trace-metals-persistent-organic-pollutants-in-albacore-tuna-from-western-indian-and-south-eastern-atlantic-oceans-trophic-influence-and-potential-as-tracers-of-populations
#13
Tiphaine Chouvelon, Christophe Brach-Papa, Dominique Auger, Nathalie Bodin, Sandrine Bruzac, Sylvette Crochet, Maxime Degroote, Stephanie J Hollanda, Clarisse Hubert, Joël Knoery, Catherine Munschy, Alexis Puech, Emmanuelle Rozuel, Bastien Thomas, Wendy West, Jérôme Bourjea, Natacha Nikolic
Albacore tuna (Thunnus alalunga) is a highly commercial fish species harvested in the world's Oceans. Identifying the potential links between populations is one of the key tools that can improve the current management across fisheries areas. In addition to characterising populations' contamination state, chemical compounds can help refine foraging areas, individual flows and populations' structure, especially when combined with other intrinsic biogeochemical (trophic) markers such as carbon and nitrogen stable isotopes...
April 27, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28458168/a-rapid-method-for-estimation-of-pu-isotopes-in-urine-samples-using-high-volume-centrifuge
#14
Ranjeet Kumar, D D Rao, Rupali Dubla, J R Yadav
The conventional radio-analytical technique used for estimation of Pu-isotopes in urine samples involves anion exchange/TEVA column separation followed by alpha spectrometry. This sequence of analysis consumes nearly 3-4 days for completion. Many a times excreta analysis results are required urgently, particularly under repeat and incidental/emergency situations. Therefore, there is need to reduce the analysis time for the estimation of Pu-isotopes in bioassay samples. This paper gives the details of standardization of a rapid method for estimation of Pu-isotopes in urine samples using multi-purpose centrifuge, TEVA resin followed by alpha spectrometry...
April 20, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28455820/a-review-of-source-tracking-techniques-for-fine-sediment-within-a-catchment
#15
REVIEW
Zhuo Guan, Xiang-Yu Tang, Jae E Yang, Yong Sik Ok, Zhihong Xu, Taku Nishimura, Brian J Reid
Excessive transport of fine sediment, and its associated pollutants, can cause detrimental impacts in aquatic environments. It is therefore important to perform accurate sediment source apportionment to identify hot spots of soil erosion. Various tracers have been adopted, often in combination, to identify sediment source type and its spatial origin; these include fallout radionuclides, geochemical tracers, mineral magnetic properties and bulk and compound-specific stable isotopes. In this review, the applicability of these techniques to particular settings and their advantages and limitations are reviewed...
April 28, 2017: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/28447675/back-exchange-a-novel-approach-to-quantifying-oxygen-diffusion-and-surface-exchange-in-ambient-atmospheres
#16
Samuel J Cooper, Mathew Niania, Franca Hoffmann, John A Kilner
A novel two-step Isotopic Exchange (IE) technique has been developed to investigate the influence of oxygen containing components of ambient air (such as H2O and CO2) on the effective surface exchange coefficient (k*) of a common mixed ionic electronic conductor material. The two step 'back-exchange' technique was used to introduce a tracer diffusion profile, which was subsequently measured using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The isotopic fraction of oxygen in a dense sample as a function of distance from the surface, before and after the second exchange step, could then be used to determine the surface exchange coefficient in each atmosphere...
May 17, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28444793/dietary-mannoheptulose-does-not-alter-glucose-or-lipid-metabolism-in-adult-labrador-retrievers
#17
L L McKnight, J France, D Wright, G Davenport, A K Shoveller
Mannoheptulose (MH), a glycolytic inhibitor, has been preliminarily investigated as a novel functional food ingredient for dogs. This study aimed to determine the effects of dietary MH, delivered as an extract of un-ripened avocados, on fatty acid and glucose kinetics in healthy adult Labrador Retriever dogs (n = 12 dogs). The study was a double-blindcrossover with each dog receiving both dietary treatments, control (CON) and MH (400 mg/kg of diet), in random order. Glucose and glycerol plasma turnover (Ra) and oxidation (Ox) were measured in fasting and in response to repeated meal feeding ("fed") with stable isotope tracers (U-(13) C-glucose, 1,1,2,3,3-D5 -glycerol) and indirect calorimetry...
April 26, 2017: Journal of Animal Physiology and Animal Nutrition
https://www.readbyqxmd.com/read/28440654/holocene-atmospheric-mercury-levels-reconstructed-from-peat-bog-mercury-stable-isotopes
#18
Maxime Enrico, Gaël Le Roux, Lars-Eric Heimbürger, Pieter Van Beek, Marc Souhaut, Jérome Chmeleff, Jeroen E Sonke
Environmental regulations on mercury (Hg) emissions and associated ecosystem restoration are closely linked to what Hg levels we consider natural. It is widely accepted that atmospheric Hg deposition has increased by a factor 3 ± 1 since preindustrial times. However, no long-term historical records of actual atmospheric gaseous elemental Hg (GEM) concentrations exist. In this study we report Hg stable isotope signatures in Pyrenean peat records (southwestern Europe) that are used as tracers of Hg deposition pathway (Δ(200)Hg, wet vs dry Hg deposition) and atmospheric Hg sources and cycling (δ(202)Hg, Δ(199)Hg)...
May 9, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28434712/evidence-for-an-imidazoline-by-product-from-glycans-using-tandem-mass-spectrometry
#19
Robert J Duff, Elaine Smith, Wenzhou Li, Szilan Fodor
Herein is reported the separation and identification of a previously unknown imidazoline by-product originating from the fluorescent labeling procedure when applied to enzymatically released N-linked glycans of a human IgG1. The imidazoline by-product was generated via the reductive amination procedure with either sodium cyanoborohydride or 2-picoline borane. Using ultra performance liquid chromatography (UPLC) in conjunction with hydrophilic interaction-based chromatography (HILIC), the 2-aminobenzoic acid (2-AA)-labeled glycans were well-resolved from imidazoline by-products to facilitate direct identification utilizing electrospray ionization mass spectrometry (ESI-MS) with fragmentation...
April 18, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28428694/a-microarray-immunoassay-for-serum-thyrotropin-and-thyroglobulin-using-antibodies-immobilized-on-track-etched-membranes
#20
Bharti Jain, J Kumarasamy, Chandrakala Gholve, Savita Kulkarni, M G R Rajan
Serum thyroglobulin (Tg) and thyroid stimulating hormone (TSH) measurements have evolved as important analytes for monitoring the prognosis of patients with differentiated thyroid cancer, post-thyroidectomy. Individual analyte immunoassay is the current practice in clinical pathology, but the simultaneous assay for all relevant analytes for a given disease, can reduce assay costs, improve patient compliance and give the clinician more information for an unequivocal diagnosis. Microarray immunoassay (MI) can achieve this goal and, hence, we have developed and validated a immuno-radiometric MI for quantitation of serum TSH and Tg by using highly micro-porous polycarbonate (PC) track-etched membranes (TEM) to immobilize the monoclonal anti-TSH and polyclonal anti-Tg antibodies in ~1 mm diameter spots...
June 2017: Indian Journal of Clinical Biochemistry: IJCB
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