Search Results - "Leung, Gary N.W."

Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography–mass spectrometry by Kwok, Wai Him, Ho, Emmie N. M., Lau, Ming Yip, Leung, Gary N. W., Wong, April S. Y., Wan, Terence S. M.

“…In recent years, there has been an ongoing focus for both human and equine doping control laboratories on developing detection methods to control the misuse of…”
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In vitro metabolism studies of desoxy-methyltestosterone (DMT) and its five analogues, and in vivo metabolism of desoxy-vinyltestosterone (DVT) in horses by Kwok, Wai Him, Kwok, Karen Y., Leung, David K. K., Leung, Gary N. W., Wong, Colton H. F., Wong, Jenny K. Y., Wan, Terence S. M.

“…The positive findings of norbolethone in 2002 and tetrahydrogestrinone in 2003 in human athlete samples confirmed that designer steroids were indeed being…”
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Screening of drugs in equine plasma using automated on-line solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry by Kwok, W.H., Leung, David K.K., Leung, Gary N.W., Wan, Terence S.M., Wong, Colton H.F., Wong, Jenny K.Y.

“…A rapid liquid chromatography–tandem mass spectrometry (LC–MS–MS) method was developed for the simultaneous screening of 19 drugs of different classes in…”
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High throughput screening of sub-ppb levels of basic drugs in equine plasma by liquid chromatography–tandem mass spectrometry by Leung, Gary N.W., Leung, David K.K., Wan, Terence S.M., Wong, Colton H.F.

“…This paper describes a high throughput LC–MS–MS method for the screening of 75 basic drugs in equine plasma at sub-ppb levels. The test scope covers…”
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Screening of over 100 drugs in horse urine using automated on-line solid-phase extraction coupled to liquid chromatography-high resolution mass spectrometry for doping control by Kwok, W.H., Choi, Timmy L.S., Tsoi, Yeuki Y.K., Leung, Gary N.W., Wan, Terence S.M.

“…•A on-line SPE-LC/HRMS method for doping control is developed.•Simultaneous detection of 118 drugs of diverse drug classes in equine urine.•The estimated LoDs…”
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Detection of bioactive peptides including gonadotrophin‐releasing factors (GnRHs) in horse urine using ultra‐high performance liquid chromatography–high resolution mass spectrometry (UHPLC/HRMS) by Kwok, Karen Y., Choi, Timmy L. S., Kwok, Wai Him, Lau, Ming Yip, Leung, Elvis M. K., Leung, Gary N. W., Wong, Jenny K. Y., Wan, Terence S. M., Adrian, Farrington F., Prabhu, Anil, Ho, Emmie N. M.

“…The use of bioactive peptides as a doping agent in both human and animal sports has become increasingly popular in recent years. As such, methods to control…”
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Metabolic study of androsta-1,4,6-triene-3,17-dione in horses using liquid chromatography/high resolution mass spectrometry by Kwok, Wai Him, Leung, Gary N.W., Wan, Terence S.M., Curl, Peter, Schiff, Peter J.

“…[Display omitted] •Direct detection and identification of phase I and II metabolites using LC–HRMS.•Metabolic pathway for ATD in horse is proposed.•Metabolites…”
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A high‐throughput and broad‐spectrum screening method for analysing over 120 drugs in horse urine using liquid chromatography–high‐resolution mass spectrometry by Wong, Jenny K.Y., Chan, George H.M., Choi, Timmy L.S., Kwok, Karen Y., Lau, Ming Y., Leung, Gary N.W., Wan, Terence S.M., Ho, Emmie N.M.

“…A high‐throughput method has been developed for the doping control analysis of 124 drug targets, processing up to 154 horse urine samples in as short as 4.5 h,…”
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Administration study of recombinant human relaxin‐2 in horse for doping control purpose by Kwok, Wai Him, Choi, Timmy L.S., Leung, Gary N.W., Wong, April S.Y., Yue, Samuel K., Wan, Terence S.M., Ho, Emmie N.M.

“…The insulin‐like peptide relaxin (RLX), an endogenous peptide hormone produced in human for pregnancy and reproduction, is also known to exert a range of…”
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Doping control analysis of anabolic steroids in equine urine by gas chromatography‐tandem mass spectrometry by Wong, April S. Y., Leung, Gary N. W., Leung, David K. K., Wan, Terence S. M.

“…Anabolic steroids are banned substances in equine sports. Gas chromatography‐mass spectrometry (GC‐MS) has been the traditional technique for doping control…”
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Doping control analysis of lithium in horse urine and plasma by inductively coupled plasma mass spectrometry by Choi, Timmy L. S., Wong, Jenny K. Y., Ho, Emmie N. M., Kwok, Wai Him, Leung, Gary N. W., Curl, Peter, Wan, Terence S. M.

“…Lithium salts are commonly prescribed to treat bipolar disorder in humans. They are effective for the treatment of acute mania and the prophylaxis of manic…”
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Identification of porcine relaxin in plasma by liquid chromatography‐high resolution mass spectrometry by Wong, April S. Y., Ho, Emmie N. M., Kwok, W. H., Leung, Gary N. W., Shen, Yuehong, Qi, Robert Z., Yue, Samuel K., Wan, Terence S. M.

“…Relaxin (RLX) has demonstrated diverse pharmacological effects in various scientific and clinical studies. The emergence of porcine relaxin (pRLX) has raised…”
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Metabolic studies of formestane in horses by Leung, Gary N. W., Kwok, W. H., Wan, Terence S. M., Lam, Kenneth K. H., Schiff, Peter J.

“…Formestane (4‐hydroxyandrost‐4‐ene‐3,17‐dione) is an irreversible steroidal aromatase inhibitor with reported abuse in human sports. In 2011, our laboratory…”
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Unusual observations during steroid analysis by Kwok, Wai Him, Leung, David K. K., Leung, Gary N. W., Tang, Francis P. W., Wan, Terence S. M., Wong, Colton H. F., Wong, Jenny K. Y.

“…In September 2005, our laboratory detected the presence of 4‐androstene‐3,17‐dione and androsterone in a standard steroid screen of a post‐race gelding urine…”
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Metabolic studies of 1-testosterone in horses by Kwok, W. H., Ho, Emmie N. M., Leung, Gary N. W., Tang, Francis P. W., Wan, Terence S. M., Wong, Henry N. C., Yeung, John H. K.

“…1‐Testosterone (17β‐hydroxy‐5α‐androst‐1‐en‐3‐one), a synthetic anabolic steroid, has been described as one of the most effective muscle‐building supplements…”
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Metabolic studies of mesterolone in horses by Ho, Emmie N.M., Leung, David K.K., Leung, Gary N.W., Wan, Terence S.M., Wong, Henry N.C., Xu, Xiaohua, Yeung, John H.K.

“…Mesterolone (1α-methyl-5α-androstan-17β-ol-3-one) is a synthetic anabolic androgenic steroid (AAS) with reported abuses in human sports. As for other AAS,…”
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In vitro and in vivo studies of androst-4-ene-3,6,17-trione in horses by gas chromatography-mass spectrometry by Leung, Gary N. W., Tang, Francis P. W., Wan, Terence S. M., Wong, Colton H. F., Lam, Kenneth K. H., Stewart, Brian D.

“…This paper describes the application of gas chromatography–mass spectrometry (GC‐MS) for in vitro and in vivo studies of 6‐OXO in horses, with a special aim to…”
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Identification of recombinant human relaxin-2 in equine plasma by liquid chromatography-high resolution mass spectrometry by Kwok, Wai Him, Ho, Emmie N. M., Leung, Gary N. W., Wong, April S. Y., Yue, Samuel K., Wan, Terence S. M.

“…Relaxin (RLX) is a peptide hormone belonging to the relaxin‐like peptide family. Relaxin‐2 (RLX‐2), a heteromeric polypeptide consisting of an A‐chain (24…”
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High-throughput screening of corticosteroids and basic drugs in horse urine by liquid chromatography-tandem mass spectrometry by Leung, Gary N.W., Chung, Evonne W., Ho, Emmie N.M., Kwok, W.H., Leung, David K.K., Tang, Francis P.W., Wan, Terence S.M., Yu, Nola H.

“…This paper describes two high-throughput liquid chromatography-tandem mass spectrometry (LC-MS-MS) methods for the screening of two important classes of drugs…”
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A bottom-up approach in estimating the measurement uncertainty and other important considerations for quantitative analyses in drug testing for horses by Leung, Gary N.W., Ho, Emmie N.M., Kwok, W. Him, Leung, David K.K., Tang, Francis P.W., Wan, Terence S.M., Wong, April S.Y., Wong, Colton H.F., Wong, Jenny K.Y., Yu, Nola H.

“…Quantitative determination, particularly for threshold substances in biological samples, is much more demanding than qualitative identification. A proper…”
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