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Chromatographic and Electrophoretic Strategies for the Chiral Separation and Quantification of D- and L-Threo Methylphenidate in Biological MatricesAllen, Serena A., Pond, Brooks B. 01 January 2014 (has links)
Commercially available methylphenidate (MPH) exists as a racemic mixture composed of the d- and l-threo enantiomers. Various pharmacokinetic studies of MPH have shown a greater pharmacological potency of the d-threo enantiomer. Furthermore, it was deduced that the stereoselective cleavage of MPH to produce ritalinic acid (RA) by human carboxylesterase results in a higher oral bioavailability of the d-threo enantiomer. As a requirement for pharmaceutical regulation authorities, efforts have been made to determine the differential biological distribution of d- and l-threo MPH and RA enantiomers. In support of these efforts, numerous analytical procedures have been developed for the chiral separation and quantification of MPH enantiomers in a variety of biological matrices. The available methodologies accomplish the enantioseparation and quantification of MPH using gas chromatography, liquid chromatography or capillary electrophoretic techniques coupled with a variety of detectors. The current review discusses the technical procedures involved, and the sensitivity and selectivity of these assays.
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Quantitative Determination of Total Methamphetamine and Active Metabolites in Rat Tissue by Liquid Chromatography With Tandem Mass Spectrometric DetectionHendrickson, Howard, Laurenzana, Elizabeth, Owens, S. Michael 22 November 2006 (has links)
High-throughput liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) methodology for the determination of methamphetamine (METH), amphetamine (AMP), 4-hydroxymethamphetamine (4-OH-METH), and 4-hydroxyamphetamine (4-OH-AMP) was developed and validated using simple trichloroacetic acid sample treatment. The method was validated in rat serum, brain, and testis. Lower limits-of-quantitation (LOQ) for METH and AMP were 1 ng·mL-1 using positive ion electrospray tandem mass spectrometry (MS/MS). The accuracy of the method was within 25% of the actual values over a wide range of analyte concentrations. The within-assay precision was better than 12% (coefficient of variation). The method was linear over a wide dynamic range (0.3-1000 ng·mL-1). Quantitation was possible in all 3 matrices using only serum standards because of minimal matrix-associated ion effects or the use of an internal standard. Finally, the LC-MS/MS method was used to determine serum, brain, and testis METH and AMP concentrations during a subcutaneous infusion (5.6 mg kg-1 day-1) of METH in rats. Concentrations of 4-OH-AMP and 4-OH-METH were below the LOQ in experimental samples. The bias introduced by using serum calibrators for the determination of METH and AMP concentrations in testis and brain was less than 8% and insignificant relative to the interanimal variability.
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Analysis of ketamine and xylazine in fur and bones using multidimensional liquid chromatography tandem mass spectrometryKaranth, Neesha Claire 21 February 2019 (has links)
While ketamine is traditionally administered for anesthesia or pain management, illicit usage is often seen in forensic cases either as a recreational drug or as a tool in drug-facilitated sexual assault. Xylazine is an anesthetic agent used in veterinary medicine and does not have FDA approval for use in humans. However, it has recently been observed as a cutting agent in heroin. Post-mortem specimens present many challenges when it comes to toxicological analysis. Due to compound degradation and decomposition factors, analytes present at trace levels may be missed in blood and urine. Hair, bone, and insects have recently been investigated as alternative matrices for postmortem analysis due to their increased durability compared to more traditional matrices. However, this durability increases the difficulties in extracting and isolating compounds of interest from these matrices via traditional extraction and chromatography methods. These methods require lengthy extraction times and extensive cleanup steps in order to obtain samples suitable for analysis. Utilizing multiple instrumentation combinations, analysts are able to detect compounds at trace levels. Through the use of multidimensional chromatography, several time-consuming extraction steps can be eliminated while still retaining the ability of trace level detection and quantitation. Using Waters Oasis® HLB PRiME solid phase extraction cartridges using a methanol pH10 loading and an acetonitrile pH3 elution, a solvent extraction yielded linear dynamic ranges of 2pg/mL-1ng/mL and 5pg/mL-1ng/mL for xylazine and ketamine respectively.
Rat specimens utilized in this project were treated as per an Institutional Animal Care and Use Committee (IACUC) protocol. The test rodents received an acute dosage of 2mg/mL of xylazine and 24mg/mL of ketamine approximately half an hour prior to death. The 14 test samples were placed outside directly on the ground at the Boston University Forensic Anthropology Outdoor Research Facility (Holliston, MA, U.S.A.) for a period of 6 months. A 15th rat was kept in -20°C until analysis to serve as a Time=0 sample. The outdoor samples were recovered and de-fleshed along with the Time=0 sample manually.
Drug-free hair samples were donated anonymously as per Internal Review Board (IRB) protocols.
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γ線照射によって生じるクリスタリン中の酸化、脱アミド化部位の迅速分析金, 仁求 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第19517号 / 理博第4177号 / 新制||理||1600(附属図書館) / 32553 / 京都大学大学院理学研究科化学専攻 / (主査)教授 藤井 紀子, 教授 三木 邦夫, 教授 杉山 弘 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
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A method for chemical proteomics based on the selective localization of labeling molecules in living systems / 生体における小分子局在に基づいたケミカルプロテオミクス手法Yasueda, Yuuki 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19752号 / 工博第4207号 / 新制||工||1649(附属図書館) / 32788 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 濵地 格, 教授 梅田 眞郷, 教授 跡見 晴幸 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
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THRAP3 interacts with and inhibits the transcriptional activity of SOX9 during chondrogenesis / THRAP3は軟骨発生の際にSOX9と結合し、その転写活性を抑制するSono, Takashi 23 January 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20793号 / 医博第4293号 / 新制||医||1025(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 妻木 範行, 教授 鈴木 茂彦, 教授 瀬原 淳子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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Investigation of Ribonucleic Acid Post-transcriptional Modifications by Optimized LC-MS/MS MethodsZhao, Ruoxia 05 October 2021 (has links)
No description available.
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Structure and biological activities of hydrophobic short chain pyroglutamyl peptides in fermented foods and food protein hydrolysates / 発酵食品及び食品タンパク質加水分解物中に存在する疎水性短鎖ピログルタミルペプチドの構造とその生理機能Shirako, Saki 23 March 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22499号 / 農博第2403号 / 新制||農||1077(附属図書館) / 学位論文||R2||N5279(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 佐藤 健司, 教授 菅原 達也, 准教授 豊原 治彦 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
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Séquençage des peptides par spectrométrie de masse en tandem à ionisation par électronébulisationBergeron, Annik January 2001 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
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Metabolic Profiling Analysis of Four Date Palm (Phoenix dactylifera L.) Cultivars from Saudi Arabia and Tunisia Using LC-MS and GC–MS AnalysisAlsuhaymi, Shuruq 07 1900 (has links)
Date palm (Phoenix dactylifera L.) is a fruit-bearing tree with numerous potential sustainable applications. Since ancient times, it has been considered a stable, secure, and sustainable food. This work provides comprehensive metabolic profiling of both parts, flesh and seed, of four P. dactylifera cultivars; Ajwa, Anbara, Sukkari, and Degelt Nour, which originated from two countries, Saudi Arabia, Tunisia.
The analysis performed using mass spectrometry-untargeted metabolomics approaches, included a combination of LC-MS and GC-MS coupled to multivariate statistical analysis to reveal the differences in metabolite compositions among date varieties. The LC-MS seed results showed several classes of metabolites that belong to the flavonoids, phenolic acids, and amino acids derivatives, including citric acid, malic acid, lactic acid, hydroxyadipic acid, caffeic acid, which were at high concentrations in AJS followed by DNS and ARS. The LC-MS flesh analysis displayed that DNF had a high level of Isoquercitrin (flavonoid compound) and sinapic acid, and AJF was high concentrations level in hydroxyadipic acid and ascorbic acid. GC-MS concluded that seed samples of four date varieties are richer in metabolites classes than the flesh samples. The metabolites contributed to the seed metabolite compositions included several classes of amino acids, hydrocinnamic acids (caffeic, ferulic and sinapic acids), antioxidant phenolics, and long-chain fatty acids. The PCA and its loading analysis demonstrated the discriminating metabolites that were responsible for date varieties segregation, as HCA displayed the metabolic patterns and groups of metabolites that drive the clustering of the date samples, two groups of dates clustered together (AR and AJ) and (SR and DN). These clusterings are based on the similarities and differences observed in the metabolite compositions of the studied date samples that could be explained by differences in various metabolic responses and the environmental conditions, genotypes and geographical regions. This extensive date palm information would increase the potential of date fruits and seeds as low-cost sources of natural diet that may provide nutritious and bioactive components in the food and pharmaceutical fields to produce value-added products.
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