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James Chun Yip Chan, Dorinda Yan Qin Kioh, Gaik Chin Yap, Bee Wah Lee, Eric Chun Yong Chan
A novel liquid chromatography tandem mass spectrometry (LCMSMS) method for the quantitative measurement of gut microbial-derived short-chain fatty acids (SCFAs) in human infant stool has been developed and validated. Baseline chromatographic resolution was achieved for 12 SCFAs (acetic, butyric, caproic, 2,2-dimethylbutyric, 2-ethylbutyric, isobutyric, isovaleric, 2-methylbutyric, 4-methylvaleric, propionic, pivalic and valeric acids) within an analysis time of 15min. A novel sequential derivatization of endogenous and spiked SCFAs in stool via (12)C- and (13)C-aniline respectively, facilitated the accurate quantitation of (12)C-aniline derivatized endogenous SCFAs based on calibration of exogenously (13)C-derivatized SCFAs...
January 28, 2017: Journal of Pharmaceutical and Biomedical Analysis
Alexandra Elisabeth Kulle, Thomas Reinehr, Gunter Simic-Schleicher, Nadine C Hornig, Paul-Martin Holterhus
BACKGROUND: Dehydroepiandrosterone-sulfate (DHEAS) and 17-hydroxypregnenolone (17OHPreg) are important for understanding the Δ5-pathway, e.g. in adrenarche and obesity. While mass spectrometry has become the state-of-the-art method for quantifying steroids, there are few comprehensive age-, sex- and pubertal stage-specific reference ranges for children. AIMS: To develop a sensitive and reliable UPLC-MS/MS method for simultaneous quantification of DHEAS and 17OHPreg, and establish the entire age-, sex- and pubertal stage-specific reference ranges in children...
November 3, 2016: Journal of Clinical Endocrinology and Metabolism
Rafidah Hod, Wided Kouidhi, Mustafa Ali Mohd, Ruby Husain
Epidemiological studies indicate lower prevalences of breast and prostate cancers and cardiovascular disease in Southeast Asia where vegetarianism is popular and diets are traditionally high in phytoestrogens. This study assessed plasma isoflavones in vegetarian and non-vegetarian Malaysian men according to age. Daidzein, genistein, equol (a daidzein metabolite), formononetin, biochanin A, estrone, estradiol and testosterone were measured by validated liquid chromatography tandem mass spectrometry (LCMSMS)...
2016: Asia Pacific Journal of Clinical Nutrition
Juthamath Komvongsa, Sukanya Luang, Joaquim V Marques, Kannika Phasai, Laurence B Davin, Norman G Lewis, James R Ketudat Cairns
BACKGROUND: Rice Os9BGlu31 is a transglucosidase that can transfer glucose to phenolic acids, flavonoids, and phytohormones. Os9BGlu31 displays a broad specificity with phenolic 1-O-β-D-glucose esters acting as better glucose donors than glucosides, whereas the free phenolic acids of these esters are also excellent acceptor substrates. METHODS: Based on homology modeling of this enzyme, we made single point mutations of residues surrounding the acceptor binding region of the Os9BGlu31 active site...
July 2015: Biochimica et Biophysica Acta
Nelly Mauras, Richard J Santen, Gerardo Colón-Otero, Jobayer Hossain, Qingqing Wang, Clementina Mesaros, Ian A Blair
CONTEXT: Estrogen levels and their metabolites are higher in obese vs lean postmenopausal women, and obesity increases breast cancer risk. Quinone derivatives of 4-hydroxylated estrogen metabolites, independently of the estrogen receptor, cause depurination and impaired DNA repair (genotoxic). 16α-Hydroxy (16α-OH)-estrone (E1), eg, promotes tumor proliferation and 2-methoxy-estradiol (E2) may be chemoprotective. Childhood obesity increases breast cancer death risk in women, but levels of estrogen derivatives had not been previously studied in young children...
June 2015: Journal of Clinical Endocrinology and Metabolism
M Griffin, J Eyre, S Dack, J Wright
AIMS: The majority of haematology laboratories use automated high-performance liquid chromatography (HPLC) as a primary method in the screening of samples for haemoglobin variants and thalassaemia. HPLC detects adducted fractions, such as HbA1C and other peaks of unknown significance. The National Health Service (NHS) Sickle and Thalassaemia Screening Programme does not mandate further assessment of these unknown peaks, but their presence may cause concern or precipitate detailed investigations...
May 2015: Journal of Clinical Pathology
Tom Preston
This paper discusses some of the recent improvements in instrumentation used for stable isotope tracer measurements in the context of measuring retinol stores, in vivo. Tracer costs, together with concerns that larger tracer doses may perturb the parameter under study, demand that ever more sensitive mass spectrometric techniques are developed. GCMS is the most widely used technique. It has high sensitivity in terms of sample amount and uses high resolution GC, yet its ability to detect low isotope ratios is limited by background noise...
2014: International Journal for Vitamin and Nutrition Research. Journal International de Vitaminologie et de Nutrition
Anne Barden, Emilie Mas, Kevin D Croft, Michael Phillips, Trevor A Mori
Resolution of inflammation is an active process involving specialized proresolving mediators (SPM) formed from the n-3 fatty acids. This study examined the effect of n-3 fatty acid supplementation and aspirin on plasma SPMs in healthy humans. Healthy volunteers (n = 21) were supplemented with n-3 fatty acids (2.4g/day) for 7 days with random assignment to take aspirin (300 mg/day) or placebo from day 5 to day 7. Blood was collected at baseline (day 0), day 5, and day 7. Plasma 18R/S-HEPE, E-series resolvins, 17R/S-HDHA, D-series resolvins, 14R/S-HDHA, and MaR-1 were measured by LC/MS/MS...
November 2014: Journal of Lipid Research
Simon J Salter, Paul Cook, Justin H Davies, Annie E Armston
BACKGROUND: Monitoring of treatment for patients diagnosed with congenital adrenal hyperplasia (CAH) can be performed by measuring the concentration of 17α-hydroxyprogesterone (17OHP) in bloodspots collected on filter papers. A method is described here for measuring 17OHP by liquid chromatography tandem mass spectrometry (LCMSMS). METHODS: 17OHP was extracted by liquid-liquid extraction and analysed by LCMSMS. The method was validated for sensitivity, specificity, linearity, recovery, ion suppression, precision and bias...
January 2015: Annals of Clinical Biochemistry
Andreas Austgulen Westin, George Mjønes, Ola Burchardt, Ole Martin Fuskevåg, Lars Slørdal
The aim of this study was to evaluate whether physical exercise or food deprivation may increase cannabinoid levels in serum or urine in abstinent chronic cannabis users. The study took place in a drug detoxification ward parallel to study participants receiving treatment. Six chronic, daily cannabis users (one female, five males, average age 30.0 years; BMI 20.8) were exposed to a 45-min. moderate-intensity workout and a 24-hr period of food deprivation. Serum samples were drawn prior to and after interventions and analysed for ∆9-tetrahydrocannabinol (THC) and 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THCCOOH) by liquid chromatography-tandem mass spectrometry (LCMSMS), and all voided urine was tested for THCCOOH by LCMSMS and normalized to the creatinine levels, yielding ng/mg ratios...
November 2014: Basic & Clinical Pharmacology & Toxicology
W J Hunter
Biobarriers remove, via precipitation, the metalloid selenite (SeO₃⁻²) from groundwater; a process that involves the biological reduction of soluble SeO₃⁻² to insoluble elemental red selenium (Se⁰). The enzymes associated with this reduction process are poorly understood. In Rhizobium selenitireducens at least two enzymes are potentially involved; one, a nitrite reductase reduces SeO₃⁻² to Se⁰ but another protein may also be involved which is investigated in this study. Proteins from R. selenitireducens cells were precipitated with ammonium sulfate and run on native electrophoresis gels...
March 2014: Current Microbiology
M Joyce Dinglasan-Panlilio, Shristi S Prakash, Joel E Baker
Perfluorinated compounds (PFCs) are persistent organic contaminants detected in various environmental matrices including sediment, air, biota, and water. The objectives of this study was to evaluate the occurrence of these contaminants within the surface waters of the Pacific Northwest region and through relative concentrations and ratios, to assess their possible sources. Surface waters were extracted and analyzed by liquid chromatography tandem mass spectrometry (LCMSMS). Perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the most commonly detected PFCs...
January 15, 2014: Marine Pollution Bulletin
Frederic D L Leusch, Stuart J Khan, M Monique Gagnon, Pam Quayle, Trang Trinh, Heather Coleman, Christopher Rawson, Heather F Chapman, Palenque Blair, Helen Nice, Tarren Reitsema
We investigated water quality at an advanced water reclamation plant and three conventional wastewater treatment plants using an "ecotoxicity toolbox" consisting of three complementary analyses (chemical analysis, in vitro bioanalysis and in situ biological monitoring), with a focus on endocrine disruption. The in vitro bioassays were chosen to provide an appropriately wide coverage of biological effects relevant to managed aquifer recharge and environmental discharge of treated wastewater, and included bioassays for bacterial toxicity (Microtox), genotoxicity (umuC), photosynthesis inhibition (Max-I-PAM) and endocrine effects (E-SCREEN and AR-CALUX)...
March 1, 2014: Water Research
Christelle Margoum, Céline Guillemain, Xi Yang, Marina Coquery
Stir bar sorptive extraction followed by liquid desorption and high performance liquid chromatography with tandem mass spectrometry (SBSE-LD-LC-MSMS) has been developed for the determination of 15 pesticides or selected metabolites from different families (herbicides, insecticides, fungicides) in surface water samples. The optimization of parameters that could influence SBSE-LD efficiency was carried out by means of experimental design. Optimized conditions were established as follows concerning extraction time, stirring speed, aqueous medium characteristics (ionic strength and polarity) and back desorption solvent and time, respectively: 3 h (800 rpm), addition of 10% of sodium chloride, no addition of methanol as organic modifier, and 15 min ultrasonic desorption in equivolume mixtures of acetonitrile-methanol...
November 15, 2013: Talanta
Karl B Scheidweiler, Sarah K Himes, Xiaohong Chen, Hua-Fen Liu, Marilyn A Huestis
Currently, ∆9-tetrahydrocannabinol (THC) is the analyte quantified for oral fluid cannabinoid monitoring. The potential for false-positive oral fluid cannabinoid results from passive exposure to THC-laden cannabis smoke raises concerns for this promising new monitoring technology. Oral fluid 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THCCOOH) is proposed as a marker of cannabis intake since it is not present in cannabis smoke and was not measureable in oral fluid collected from subjects passively exposed to cannabis...
July 2013: Analytical and Bioanalytical Chemistry
Sheila Okoth, Beatrice Nyongesa, Vincent Ayugi, Erastus Kang'ethe, Hannu Korhonen, Vesa Joutsjoki
Two agro-ecological zones in Kenya were selected to compare the distribution in maize of Aspergillus spp. and their toxigenicity. These were Nandi County, which is the main maize growing region in the country but where no human aflatoxicoses have been reported, and Makueni County where most of the aflatoxicosis cases have occurred. Two hundred and fifty-five households were sampled in Nandi and 258 in Makueni, and Aspergillus was isolated from maize. Aspergillus flavus and A. parasiticus isolates were tested for the presence of aflD and aflQ genes...
November 2012: Toxins
Sarah Miesner, Holly Frosch, Kelly Kindscher, Shane Tichy, Kirk P Manfredi
Two new benzyl benzoate glycosides were isolated from the leaves and stems of the native North American prairie plant Oligoneuron rigidum (stiff goldenrod). The glycosides were isolated as a mixture of benzoate and acetate esters, which were subjected to mild base hydrolysis to facilitate full structural characterization using LCMSMS and 1D and 2D NMR data.
November 26, 2012: Journal of Natural Products
Karl B Scheidweiler, Diaa M Shakleya, Marilyn A Huestis
BACKGROUND: Mecamylamine is a nicotine antagonist under investigation in combination with nicotine replacement for smoking treatment. METHODS: A simple, rapid and reliable liquid chromatography tandem mass spectrometry (LCMSMS) method was developed and validated for quantifying nicotine, cotinine, trans-3'-hydroxycotinine, norcotinine and mecamylamine in human urine. Chromatography was performed on a Synergi PolarRP column with a gradient of 0.1% formic acid and 0...
June 14, 2012: Clinica Chimica Acta; International Journal of Clinical Chemistry
Karthikeyan Kandasamy, Vasantharaju Surenahalli Gowdra, Hariprabhu Nammalvar, Arul Kumaran Kottur S Govindarajan
A simple, highly sensitive, precise and accurate high-performance liquid chromatographic (LCMSMS) method with mass detection was developed and validated for the rapid quantification of flupirtine (CAS 75507-68-5) in rat plasma samples. The chromatographic separation was achieved with a reverse phase column (4.6 x 50 mm, 5 microm) and the mobile phase consisted of cyanomethane and 5 mM ammonium formate buffer pH 4.5 (70:30 v/v) as eluent, at a flow rate of 0.6 mL/min. Labetalol (CAS 36894-69-6) was used as an internal standard...
2011: Arzneimittel-Forschung
Richard J Honeywell, Elisa Giovannetti, G J Peters
Gemcitabine is an established chemotherapy agent in several solid tumors. Its mechanism of action has been theoretically established and this is supported with strong experimental evidence. However, certain aspects of the resistance mechanism for this agent remain elusive. We present a method of analysis using tandem liquid chromatography and mass spectrometry that provides a broader, yet more focused view of the action of gemcitabine and its primary metabolite, difluorodeoxyuridine in relation to the (deoxy) nucleoside and (deoxy) nucleotide pools in tumor cell lines...
December 2011: Nucleosides, Nucleotides & Nucleic Acids
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