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https://www.readbyqxmd.com/read/28826376/nutrition-from-the-inside-out
#1
Dennis M Bier
Nearly 50 years ago, I set out to investigate the clinical problem of hypoglycemia in children with illnesses that limited their food intake. My goal was to gather accurate and precise measurable data. At the time, I wasn't interested in nutrition as a discipline defined in its more general or popular sense. To address the specific problem that interested me required development of entirely new methods based on stable, nonradioactive tracers that satisfied the conditions of accuracy and precision. At the time, I had no inclination of the various theoretical and practical problems that would have to be solved to achieve this goal...
August 21, 2017: Annual Review of Nutrition
https://www.readbyqxmd.com/read/28822315/applications-of-radon-and-radium-isotopes-to-determine-submarine-groundwater-discharge-and-flushing-times-in-todos-os-santos-bay-brazil
#2
Vanessa Hatje, Karina Kammer Attisano, Marcelo Friederichs Landim de Souza, Barbara Mazzilli, Joselene de Oliveira, Tamires de Araújo Mora, William C Burnett
Todos os Santos Bay (BTS) is the 2nd largest bay in Brazil and an important resource for the people of the State of Bahia. We made measurements of radon and radium in selected areas of the bay to evaluate if these tracers could provide estimates of submarine groundwater discharge (SGD) and flushing times of the Paraguaçu Estuary and BTS. We found that there were a few areas along the eastern and northeastern shorelines that displayed relatively high radon and low salinities, indicating possible sites of enhanced SGD...
August 16, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28814251/the-role-of-radiopharmaceuticals-in-amiodarone-induced-thyroid-pathology
#3
Doina Piciu, Alexandru Irimie
Amiodarone is a di-iodinated benzofuran derivative and is classified as a class III antiarrhythmic agent. It is one of the most powerful and effective antiarrhythmics, being a first-line agent due to its ability to treat ventricular and supraventricular dysrhythmias; since 1960 the drug has become one of the most frequently prescribed antiarrhythmics, despite its potentially serious, side effects. By far, one of the most challenging condition is the thyroid pathology induced by this drug. Each 200 mg tablet of amiodarone contains approximately 75 mg of iodine, 3-10% from each tablet being released as free iodine...
August 16, 2017: Current Radiopharmaceuticals
https://www.readbyqxmd.com/read/28811296/a-novel-d2o-tracer-method-to-quantify-rna-turnover-as-a-biomarker-of-de-novo-ribosomal-biogenesis-in-vitro-in-animal-models-and-in-human-skeletal-muscle
#4
Matthew S Brook, Daniel J Wilkinson, W Kyle Mitchell, Jonathan L Lund, Bethan E Phillips, Nathaniel J Sweczyk, Heikki Kainulainen, Sanna Lensu, Lauren G Koch, Steve L Britton, Paul L Greenhaff, Kenneth Smith, Philip J Atherton
Current methods to quantify RNA dynamics are beset with limitations. Here, we developed a novel stable isotope (D2O)-methodology to quantify RNA synthesis (i.e. ribosomal biogenesis) in cells, animal models, and humans. Firstly, proliferating C2C12 cells were incubated in D2O-enriched media and myotubes (±) 50ng.ml(-1) IGF-1. Secondly, rat quadriceps [untrained n=9; 7-wks interval-"like" training n=13] were collected after ~3-wks D2O (70-Atom%) administration, with body-water enrichment (BWE) monitored via blood sampling...
August 15, 2017: American Journal of Physiology. Endocrinology and Metabolism
https://www.readbyqxmd.com/read/28797142/temporal-trends-of-mercury-and-organohalogen-contaminants-in-great-blue-heron-eggs-from-the-st-lawrence-river-qu%C3%A3-bec-canada-1991-2011-and-relationships-with-tracers-of-feeding-ecology
#5
Louise Champoux, Monique Boily
Since 1991, great blue heron (Ardea herodias) eggs have been collected and analyzed for mercury (Hg), persistent organic contaminants (OCs), brominated and non-brominated flame retardants (FRs) as well as stable isotopes δ(13)C and δ(15)N. In the present study, temporal trends of contaminants were analyzed in eggs sampled in four regions along the St. Lawrence River (Quebec, Canada) and inland sites using new and previously published data. Most contaminants declined significantly over time in most regions...
August 6, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28792100/understanding-sources-of-methylmercury-to-songbirds-with-stable-mercury-isotopes-challenges-and-future-directions
#6
Martin Tsz-Ki Tsui, Evan M Adams, Allyson K Jackson, David C Evers, Joel D Blum, Steven J Balogh
Mercury (Hg) stable isotope analysis is an emerging technique that has contributed to a better understanding of many aspects of the biogeochemical cycling of Hg in the environment. However, no study has yet evaluated its usefulness in elucidating the sources of methylmercury (MeHg) to songbird species, a common organism for biomonitoring of Hg in forested ecosystems. In this pilot study, we examined stable mercury isotope ratios in blood of four species of songbirds and the invertebrates they are likely foraging upon in multiple habitats in a small watershed of mixed forest and wetlands in Acadia National Park in Maine, U...
August 9, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28776982/flux-analysis-of-free-amino-sugars-and-amino-acids-in-soils-by-isotope-tracing-with-a-novel-liquid-chromatography-high-resolution-mass-spectrometry-platform
#7
Yuntao Hu, Qing Zheng, Wolfgang Wanek
Soil fluxomics analysis can provide pivotal information for understanding soil biochemical pathways and their regulation, but direct measurement methods are rare. Here, we describe an approach to measure soil extracellular metabolite (amino sugar and amino acid) concentrations and fluxes based on a (15)N isotope pool dilution technique via liquid chromatography and high-resolution mass spectrometry. We produced commercially unavailable (15)N and (13)C labeled amino sugars and amino acids by hydrolyzing peptidoglycan isolated from isotopically labeled bacterial biomass and used them as tracers ((15)N) and internal standards ((13)C)...
August 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28768294/measurement-of-metabolic-fluxes-using-stable-isotope-tracers-in-whole-animals-and-human-patients
#8
Julie A Reisz, Angelo D'Alessandro
PURPOSE OF REVIEW: Metabolic flux analysis using stable isotope labeled substrates allows for the tracing of carbon, nitrogen, and hydrogen atoms through metabolic pathways and is an invaluable tool for investigating dynamic metabolic changes occurring in health and disease. Studies of flux analysis in vivo are more technically challenging than in vitro or ex vivo but provide a highly detailed view of organ and/or systemic metabolism. We review here recent efforts in studies of diet and nutrition, non-small cell lung cancer, ischemia/reperfusion injury, and hemorrhagic shock where in vivo flux analysis was utilized to analyze metabolic modulation...
September 2017: Current Opinion in Clinical Nutrition and Metabolic Care
https://www.readbyqxmd.com/read/28763667/characterization-of-a-managed-aquifer-recharge-system-using-multiple-tracers
#9
Christian Moeck, Dirk Radny, Andrea Popp, Matthias Brennwald, Sebastian Stoll, Adrian Auckenthaler, Michael Berg, Mario Schirmer
Knowledge about the residence times of artificially infiltrated water into an aquifer and the resulting flow paths is essential to developing groundwater-management schemes. To obtain this knowledge, a variety of tracers can be used to study residence times and gain information about subsurface processes. Although a variety of tracers exists, their interpretation can differ considerably due to subsurface heterogeneity, underlying assumptions, and sampling and analysis limitations. The current study systematically assesses information gained from seven different tracers during a pumping experiment at a site where drinking water is extracted from an aquifer close to contaminated areas and where groundwater is artificially recharged by infiltrating surface water...
July 28, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28763658/relationship-between-land-use-and-sources-and-fate-of-nitrate-in-groundwater-in-a-typical-recharge-area-of-the-north-china-plain
#10
Shiqin Wang, Wenbo Zheng, Matthew Currell, Yonghui Yang, Huan Zhao, Mengyu Lv
Identification of different nitrate sources in groundwater is challenging in areas with diverse land use and multiple potential inputs. An area with mixed land-uses, typical of the piedmont-plain recharge area of the North China Plain, was selected to investigate different nitrate sources and the impact of land use on nitrate distribution in groundwater. Multiple environmental tracers were examined, including major ions, stable isotopes of water (δ(2)H-H2O, δ(18)O-H2O) and nitrate (δ(15)N-NO3(-) and δ(18)O-NO3(-))...
July 27, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28756690/continuous-measurements-of-stable-isotopes-of-carbon-dioxide-and-water-vapour-in-an-urban-atmosphere-isotopic-variations-associated-with-meteorological-conditions
#11
Ryuichi Wada, Yutaka Matsumi, Tomoki Nakayama, Tetsuya Hiyama, Yasushi Fujiyoshi, Naoyuki Kurita, Kenichiro Muramoto, Satoru Takanashi, Naomi Kodama, Yoshiyuki Takahashi
Isotope ratios of carbon dioxide and water vapour in the near-surface air were continuously measured for one month in an urban area of the city of Nagoya in central Japan in September 2010 using laser spectroscopic techniques. During the passages of a typhoon and a stationary front in the observation period, remarkable changes in the isotope ratios of CO2 and water vapour were observed. The isotope ratios of both CO2 and water vapour decreased during the typhoon passage. The decreases can be attributed to the air coming from an industrial area and the rainout effects of the typhoon, respectively...
July 30, 2017: Isotopes in Environmental and Health Studies
https://www.readbyqxmd.com/read/28747484/a-simple-plasma-retinol-isotope-ratio-method-for-estimating-%C3%AE-carotene-relative-bioefficacy-in-humans-validation-with-the-use-of-model-based-compartmental-analysis
#12
Jennifer Lynn Ford, Joanne Balmer Green, Georg Lietz, Anthony Oxley, Michael H Green
Background: Provitamin A carotenoids are an important source of dietary vitamin A for many populations. Thus, accurate and simple methods for estimating carotenoid bioefficacy are needed to evaluate the vitamin A value of test solutions and plant sources. β-Carotene bioefficacy is often estimated from the ratio of the areas under plasma isotope response curves after subjects ingest labeled β-carotene and a labeled retinyl acetate reference dose [isotope reference method (IRM)], but to our knowledge, the method has not yet been evaluated for accuracy...
July 26, 2017: Journal of Nutrition
https://www.readbyqxmd.com/read/28745515/hydrology-of-the-north-klondike-river-carbon-export-water-balance-and-inter-annual-climate-influences-within-a-sub-alpine-permafrost-catchment
#13
Anthony Lapp, Ian Clark, Andrew Macumber, Tim Patterson
Arctic and sub-arctic watersheds are undergoing significant changes due to recent climate warming and degrading permafrost, engendering enhanced monitoring of arctic rivers. Smaller catchments provide understanding of discharge, solute flux and groundwater recharge at the process level that contributes to an understanding of how larger arctic watersheds are responding to climate change. The North Klondike River, located in west central Yukon, is a sub-alpine permafrost catchment, which maintains an active hydrological monitoring station with a record of >40 years...
July 26, 2017: Isotopes in Environmental and Health Studies
https://www.readbyqxmd.com/read/28742073/biological-nitrogen-fixation-in-the-oxygen-minimum-region-of-the-eastern-tropical-north-pacific-ocean
#14
Amal Jayakumar, Bonnie X Chang, Brittany Widner, Peter Bernhardt, Margaret R Mulholland, Bess B Ward
Biological nitrogen fixation (BNF) was investigated above and within the oxygen-depleted waters of the oxygen-minimum zone of the Eastern Tropical North Pacific Ocean. BNF rates were estimated using an isotope tracer method that overcame the uncertainty of the conventional bubble method by directly measuring the tracer enrichment during the incubations. Highest rates of BNF (~4 nM day(-1)) occurred in coastal surface waters and lowest detectable rates (~0.2 nM day(-1)) were found in the anoxic region of offshore stations...
July 25, 2017: ISME Journal
https://www.readbyqxmd.com/read/28737889/application-of-resonance-ionization-mass-spectrometry-for-ultratrace-analysis-of-technetium
#15
Pascal Schönberg, Christoph Mokry, Jörg Runke, Daniela Schönenbach, Nils Stöbener, Petra Thörle-Pospiech, Norbert Trautmann, Tobias Reich
This work shows the ability of resonance ionization mass spectrometry (RIMS) to determine (99g)Tc at the ultratrace level. The characterization of the prepared samples by X-ray photoelectron spectroscopy (XPS) and optimization of the RIMS setup for this purpose, as well as the application of the RIMS method to a soil sample, are presented in this article. (97)Tc was used as a tracer isotope to determine the amount of (99g)Tc in a soil sample with RIMS. With 8.8 × 10(10) atoms of (97)Tc as the tracer, the concentration of (99g)Tc was found to be 1...
August 16, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28736501/design-of-radioiodinated-pharmaceuticals-structural-features-affecting-metabolic-stability-towards-in-vivo-deiodination
#16
REVIEW
Lorenzo Cavina, Dion van der Born, Peter H M Klaren, Martin C Feiters, Otto C Boerman, Floris P J T Rutjes
Radioiodinated pharmaceuticals are convenient tracers for clinical and research investigations because of the relatively long half-lives of radioactive iodine isotopes (i.e., (123)I, (124)I, and (131)I) and the ease of their chemical insertion. Their application in radionuclide imaging and therapy may, however, be hampered by poor in vivo stability of the C-I bond. After an overview of the use of iodine in biology and nuclear medicine, we present here a survey of the catabolic pathways for iodinated xenobiotics, including their biodistribution, accumulation, and biostability...
June 30, 2017: European Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28736244/the-use-of-stable-isotopes-in-the-study-of-human-pathophysiology
#17
Evelina Charidemou, Tom Ashmore, Julian L Griffin
The growing prevalence of metabolic diseases including fatty liver disease and Type 2 diabetes has increased the emphasis on understanding metabolism at the mechanistic level and how it is perturbed in disease. Metabolomics is a continually expanding field that seeks to measure metabolites in biological systems during a physiological stimulus or a genetic alteration. Typically, metabolomics studies provide total pool sizes of metabolites rather than dynamic flux measurements. More recently there has been a resurgence in approaches that use stable isotopes (e...
July 20, 2017: International Journal of Biochemistry & Cell Biology
https://www.readbyqxmd.com/read/28734989/hydroxyvitamin-d-assays-an-historical-perspective-from-deqas
#18
G D Carter, J Berry, R Durazo-Arvizu, E Gunter, G Jones, J Jones, H L J Makin, P Pattni, C T Sempos, P Twomey, E L Williams, S A Wise
Recent years have seen a substantial increase in demand for 25-hydroxyvitamin D (25-OHD) assays. DEQAS (the Vitamin D External Quality Assessment Scheme) has been monitoring the performance of these assays since 1989. The first DEQAS distribution was in June 1989 and results were submitted by 13 laboratories in the UK, two of which used HPLC/UV; the rest used ligand binding assays with a tritium tracer. Inter-laboratory CVs (ALTM) ranged from 29.3% (42.7 nmol/L) to 53.7% (20.0 nmol/L). Currently the scheme has participants in 56 countries using 30 methods or variants of methods...
July 19, 2017: Journal of Steroid Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28727110/calibration-and-validation-of-a-carbon-oxidation-system-and-determination-of-the-bicarbonate-retention-factor-and-the-dietary-phenylalanine-requirement-in-the-presence-of-excess-tyrosine-of-adult-female-mixed-breed-dogs
#19
A K Shoveller, J J Danelon, J L Atkinson, G M Davenport, R O Ball, P B Pencharz
Carbon oxidation methods have been used as rapid and sensitive methods to determine whole-body AA requirements in multiple species. The objectives of the current studies were to validate complete CO recovery, determine the bicarbonate retention factor, and estimate the Phe requirement, in the presence of excess Tyr, in adult dogs using the direct oxidation technique. In this series of studies, 2 oxidation chambers were constructed and calibrated to ensure accurate collection of breath CO. First, 104.6 ± 7...
July 2017: Journal of Animal Science
https://www.readbyqxmd.com/read/28724692/enhancing-studies-of-pharmacodynamic-mechanisms-via-measurements-of-metabolic-flux
#20
Natalie A Daurio, Sheng-Ping Wang, Ying Chen, Haihong Zhou, David G McLaren, Thomas P Roddy, Douglas G Johns, Denise Milot, Takhar Kasumov, Mark D Erion, David E Kelley, Stephen F Previs
Drug discovery and development efforts are largely based around a common expectation, namely, direct or indirect action on a cellular process (e.g. statin-mediated enzyme inhibition or insulin-stimulated receptor activation) will have a beneficial impact on physiological homeostasis. To expand on this, one could argue that virtually all pharmacological interventions attempt to influence the flow of traffic in a biochemical network, irrespective of disease or modality. Since stable isotope tracer kinetic methods provide a measure of traffic flow (i...
July 19, 2017: Journal of Pharmacology and Experimental Therapeutics
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