keyword
MENU ▼
Read by QxMD icon Read
search

isotopic tracer method

keyword
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
#1
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/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
#2
Yuntao Hu, Qing Zheng, Wolfgang Wanek
Soil fluxomics analysis can provide pivotal information for understanding diverse soil biochemical pathways and their regulation, but direct measurement methods are very rare. In this work, we describe an approach to measure soil extracellular metabolite (amino sugar and amino acid) fluxes based on the (15)N isotope pool dilution technique via liquid chromatography and high resolution mass spectrometry (LC/HRMS). 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 4, 2017: Analytical Chemistry
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
#3
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/28742073/biological-nitrogen-fixation-in-the-oxygen-minimum-region-of-the-eastern-tropical-north-pacific-ocean
#4
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
#5
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/28734989/hydroxyvitamin-d-assays-an-historical-perspective-from-deqas
#6
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
#7
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
#8
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
https://www.readbyqxmd.com/read/28714921/accumulation-of-microcystin-lr-rr-and-yr-in-three-freshwater-bivalves-in-microcystis-aeruginosa-bloom-using-dual-isotope-tracer
#9
Min-Seob Kim, Yeon-Jung Lee, Sun-Yong Ha, Baik-Ho Kim, Soon-Jin Hwang, Jung-Taek Kwon, Jong-Woo Choi, Kyung-Hoon Shin
Abstract: Stable isotope tracers were first applied to evaluate the Microcystis cell assimilation efficiency of Sinanodonta bivalves, since the past identification method has been limited to tracking the changes of each chl-a, clearity, and nutrient. The toxicity profile and accumulation of MC-LR, -RR and -YR in different organs (foot and digestive organs) from the three filter-feeders (Sinanodonta woodina, Sinanodonta arcaeformis, and Unio douglasiae) were assessed under the condition of toxigenic cyanobacteria (Microcystis aeruginosa) blooms through an in situ pond experiment using (13)C and (15)N dual isotope tracers...
July 17, 2017: Marine Drugs
https://www.readbyqxmd.com/read/28713554/growth-hormone-receptor-antagonism-with-pegvisomant-in-insulin-resistant-non-diabetic-men-a-phase-ii-pilot-study
#10
Ada P Lee, Kathleen Mulligan, Morris Schambelan, Elizabeth J Murphy, Ethan J Weiss
Background: Growth hormone (GH) is known to affect insulin and glucose metabolism.  Blocking its effects in acromegalic patients improves diabetes and glucose metabolism. We aimed to determine the effect of pegvisomant, a GH receptor antagonist, on insulin resistance, endogenous glucose production (EGP) and lipolysis in insulin resistant non-diabetic men.  Methods: Four men between the ages of 18-62 with a BMI of 18-35kg/m (2), with insulin resistance as defined by a HOMA-IR > 2.77, were treated for four weeks with pegvisomant 20 mg daily...
2017: F1000Research
https://www.readbyqxmd.com/read/28694298/compound-specific-isotope-analysis-resolves-the-dietary-origin-of-docosahexaenoic-acid-dha-in-the-mouse-brain
#11
R J Scott Lacombe, Vanessa Giuliano, Stefanie M Colombo, Michael T Arts, Richard P Bazinet
Docosahexaenoic acid (DHA, 22:6n-3) may be derived from two dietary sources, preformed dietary DHA or through synthesis from α-linolenic acid (ALA, 18:3n-3). However, conventional methods cannot distinguish between DHA derived from either source without the use of costly labelled tracers. In the present study, we demonstrate the proof-of-concept that compound specific isotope analysis (CSIA) by gas chromatography-isotope ratio mass spectrometry (GC-IRMS) can differentiate between sources of brain DHA based on differences in natural (13)C enrichment...
July 10, 2017: Journal of Lipid Research
https://www.readbyqxmd.com/read/28674558/analysis-of-stable-isotope-assisted-metabolomics-data-acquired-by-high-resolution-mass-spectrometry
#12
X Wei, P K Lorkiewicz, B Shi, J K Salabei, B G Hill, S Kim, C J McClain, X Zhang
Stable isotope assisted metabolomics (SIAM) uses stable isotope tracers to support studies of biochemical mechanisms. We report a suite of data analysis algorithms for automatic analysis of SIAM data acquired on a high resolution mass spectrometer. To increase the accuracy of isotopologue assignment, metabolites detected in the unlabeled samples were used as reference metabolites to generate possible isotopologue candidates for analysis of peaks detected in the labeled samples. An iterative linear regression model was developed to deconvolute the overlapping isotopic peaks of isotopologues present in a full MS spectrum, where the threshold for the weight factor was determined by a simulation study assuming different levels of Gaussian white noise contamination...
April 21, 2017: Analytical Methods: Advancing Methods and Applications
https://www.readbyqxmd.com/read/28660919/solid-matrix-transformation-and-tracer-addition-using-molten-ammonium-bifluoride-salt-as-a-sample-preparation-method-for-laser-ablation-inductively-coupled-plasma-mass-spectrometry
#13
Jay W Grate, Jhanis J Gonzalez, Matthew J O'Hara, Cynthia M Kellogg, Samuel S Morrison, David W Koppenaal, George C-Y Chan, Xianglei Mao, Vassilia Zorba, Richard E Russo
Solid sampling and analysis methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), are challenged by matrix effects and calibration difficulties. Matrix-matched standards for external calibration are seldom available and it is difficult to distribute spikes evenly into a solid matrix as internal standards. While isotopic ratios of the same element can be measured to high precision, matrix-dependent effects in the sampling and analysis process frustrate accurate quantification and elemental ratio determinations...
June 29, 2017: Analyst
https://www.readbyqxmd.com/read/28650854/recent-developments-in-deuterium-oxide-tracer-approaches-to-measure-rates-of-substrate-turnover-implications-for-protein-lipid-and-nucleic-acid-research
#14
Matthew S Brook, Daniel J Wilkinson, Philip J Atherton, Ken Smith
PURPOSE OF REVIEW: Methods that inform on dynamic metabolism that can be applied to clinical populations to understand disease progression and responses to therapeutic interventions are of great importance. This review perspective will highlight recent advances, development, and applications of the multivalent stable isotope tracer deuterium oxide (D2O) to the study of substrate metabolism with particular reference to protein, lipids, and nucleic acids, and how these methods can be readily applied within clinical and pharmaceutical research...
September 2017: Current Opinion in Clinical Nutrition and Metabolic Care
https://www.readbyqxmd.com/read/28622800/analysis-of-stable-isotope-assisted-metabolomics-data-acquired-by-gc-ms
#15
Xiaoli Wei, Biyun Shi, Imhoi Koo, Xinmin Yin, Pawel Lorkiewicz, Hamid Suhail, Ramandeep Rattan, Shailendra Giri, Craig J McClain, Xiang Zhang
Stable isotope assisted metabolomics (SIAM) measures the abundance levels of metabolites in a particular pathway using stable isotope tracers (e.g., (13)C, (18)O and/or (15)N). We report a method termed signature ion approach for analysis of SIAM data acquired on a GC-MS system equipped with an electron ionization (EI) ion source. The signature ion is a fragment ion in EI mass spectrum of a derivatized metabolite that contains all atoms of the underivatized metabolite, except the hydrogen atoms lost during derivatization...
August 8, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28596540/preparation-and-in-vivo-characterization-of-51-mncl2-as-pet-tracer-of-ca-2-channel-mediated-transport
#16
Stephen A Graves, Reinier Hernandez, Hector F Valdovinos, Paul A Ellison, Jonathan W Engle, Todd E Barnhart, Weibo Cai, Robert J Nickles
Manganese has long been employed as a T1-shortening agent in magnetic resonance imaging (MRI) applications, but these techniques are limited by the biotoxicity of bulk-manganese. Positron emission tomography (PET) offers superior contrast sensitivity compared with MRI, and recent preclinical PET studies employing (52g)Mn (t1/2: 5.6 d, β(+): 29%) show promise for a variety of applications including cell tracking, neural tract tracing, immunoPET, and functional β-cell mass quantification. The half-life and confounding gamma emissions of (52g)Mn are prohibitive to clinical translation, but the short-lived (51)Mn (t1/2: 46 min, β(+): 97%) represents a viable alternative...
June 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28584941/-trophic-and-source-amino-acids-in-trophic-estimation-a-likely-metabolic-explanation
#17
REVIEW
T C O'Connell
Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual's 'trophic' and 'source' amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in 'trophic' and 'source' amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited...
June 2017: Oecologia
https://www.readbyqxmd.com/read/28576319/chloroformate-derivatization-for-tracing-the-fate-of-amino-acids-in-cells-and-tissues-by-multiple-stable-isotope-resolved-metabolomics-msirm
#18
Ye Yang, Teresa W-M Fan, Andrew N Lane, Richard M Higashi
Amino acids have crucial roles in central metabolism, both anabolic and catabolic. To elucidate these roles, steady-state concentrations of amino acids alone are insufficient, as each amino acid participates in multiple pathways and functions in a complex network, which can also be compartmentalized. Stable Isotope-Resolved Metabolomics (SIRM) is an approach that uses atom-resolved tracking of metabolites through biochemical transformations in cells, tissues, or whole organisms. Using different elemental stable isotopes to label multiple metabolite precursors makes it possible to resolve simultaneously the utilization of these precursors in a single experiment...
July 11, 2017: Analytica Chimica Acta
https://www.readbyqxmd.com/read/28544885/overcoming-interference-with-the-detection-of-a-stable-isotopically-labeled-microtracer-in-the-evaluation-of-beclabuvir-absolute-bioavailability-using-a-concomitant-microtracer-approach
#19
Hao Jiang, Craig Titsch, Jianing Zeng, Barry Jones, Philip Joyce, Yash Gandhi, Wesley Turley, Richard Burrell, Anne F Aubry, Mark E Arnold
The oral absolute bioavailability of beclabuvir in healthy subjects was determined using a microdose (100μg) of the stable isotopically labeled tracer via intravenous (IV) infusion started after oral dosing of beclabuvir (150mg). To simultaneously analyze the concentrations of the IV microtracer ([(13)C6]beclabuvir) and beclabuvir in plasma samples, a liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) method was initially developed. Surprisingly beclabuvir significantly interfered with the IV microtracer detection when using the selected reaction monitoring (SRM) in the assay...
September 5, 2017: Journal of Pharmaceutical and Biomedical Analysis
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
#20
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...
July 2017: Journal of Nutrition
keyword
keyword
39684
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"