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Papers by Lester Taylor

Research paper thumbnail of Initial characterization of multiple endopeptidases in bovine adrenal chromaffin vesicles

Journal of the Autonomic Nervous System, 1991

Research paper thumbnail of The identification ofin vitro metabolites of bupropion using ion trap mass spectrometry

Rapid Communications in Mass Spectrometry, 1995

We have identified in uih metabolites of bupropion (Wellbutrin@) from incubations with human live... more We have identified in uih metabolites of bupropion (Wellbutrin@) from incubations with human liver S9 fraction and human liver microsomes based on molecular weight information from full scan experiments using a liquid chromatograph coupled to a quadruple ion trap mass ...

Research paper thumbnail of The use of low-energy collisionally activated dissociation negative-ion tandem mass spectrometry for the characterization of dog and human urinary metabolites of the drug BW 1370U87

Rapid Communications in Mass Spectrometry, 1994

Liquid chromatography (LC) combined with atmospheric pressure chemical ionization mass spectromet... more Liquid chromatography (LC) combined with atmospheric pressure chemical ionization mass spectrometry was used to identify phase I and II metabolites of the drug BW 1370U87 in dog and human urine. Additional analysis of individual high-performance liquid chromatograph fractions collected from dog urine by combined gas chromatography/mass spectrometry identified one metabolite which was not detected by LC/MS methods. Using negative-ion LC/MS, the majority of BW 1370U87 metabolites in human urine were identified as glucuronic acid conjugates of phase I oxidative metabolites. The negative-ion fragmentation produced by low-energy collisionally activated decomposition (CAD), studied by tandem mass spectrometry experiments, confirmed that these compounds were drug-related and allowed metabolite structures to be assigned. Product-ion spectra of the metabolites were dominated by the loss of neutral molecules from even-electron deprotonated [M-H]- ions.

Research paper thumbnail of Quantitative-qualitative data acquisition using a benchtop orbitrap mass spectrometer

Journal of the American Society for Mass Spectrometry, 2009

Current approaches to discovery-stage drug metabolism studies (pharmacokinetics, microsomal stabi... more Current approaches to discovery-stage drug metabolism studies (pharmacokinetics, microsomal stability, etc.) typically use triple-quadrupole-based approaches for quantitative analysis. This necessitates the optimization of parameters such as Q1 and Q3 m/z values, collision energy, and interface voltages. These studies detect only the specified compound and information about other components, such as metabolites, is lost. The ability to perform full-scan acquisition for quantitative analysis would eliminate the need for compound optimization while enabling the detection of metabolites and other non-drug-related endogenous components. Such an instrument would have to provide sensitivity, selectivity, dynamic range, and scan speed suitable for discovery-stage quantitative studies. In this study, a prototype benchtop Orbitrap-based mass analyzer was used to collect both quantitative and qualitative data from human microsomal incubation samples as well as rat plasma from pharmacokinetic studies. Instrumental parameters such as scan speed, resolution, and mass accuracy are discussed in relation to the requirements for a quantitativequalitative workflow. The ability to perform highly selective quantitative analysis while simultaneously characterizing metabolites from both in vitro and in vivo studies is discussed. (J Am Soc

Research paper thumbnail of Tetranuclear carbidotungsten and nitridomolybdenum clusters supported by alkoxide ligands: W4(C)(OCHMe2)12(NMe) and Mo4(N)2(OCHMe2)12

Journal of the American Chemical Society, 1985

DHHS. We are grateful for their continued support of our re-search. Partial support from the Alfr... more DHHS. We are grateful for their continued support of our re-search. Partial support from the Alfred P. Sloan Foundation in the form of a fellowship to RDL is also gratefully acknowledged. ... Supplementary Material Available: Full X-ray data and per-spective views of the molecular structure for ...

Research paper thumbnail of Characterization of Monoclonal Antibody Glycosylation: Comparison of Expression Systems and Identification of Terminal α-Linked Galactose

Analytical Biochemistry, 1997

CAMPATH-1H is a recombinant humanized murine monoclonal immunoglobulin (IgG 1 ) which recognizes ... more CAMPATH-1H is a recombinant humanized murine monoclonal immunoglobulin (IgG 1 ) which recognizes the CDw52 antigen of human lymphocytes, and has been the subject of clinical trials for the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis. Peptide mapping ...

Research paper thumbnail of Plenary Lecture: Speaker invited by the 2008 Gold Sponsor (Thermo Scientific) "Full scan data acquisition for rapid quantitative and qualitative analysis using a bench-top non-hybrid ESI-Orbitrap mass spectrometer

Markus Kellmann3; Philip Tiller4; Robert Papp1; Lester C. Taylor3 1Merck Frosst, Montreal, QC; 2T... more Markus Kellmann3; Philip Tiller4; Robert Papp1; Lester C. Taylor3 1Merck Frosst, Montreal, QC; 2Thermo Fisher Scientific (bremen) Gmbh, Bremen, GERMANY; 3Thermo Fisher

Research paper thumbnail of Initial characterization of multiple endopeptidases in bovine adrenal chromaffin vesicles

Journal of the Autonomic Nervous System, 1991

Research paper thumbnail of The identification ofin vitro metabolites of bupropion using ion trap mass spectrometry

Rapid Communications in Mass Spectrometry, 1995

We have identified in uih metabolites of bupropion (Wellbutrin@) from incubations with human live... more We have identified in uih metabolites of bupropion (Wellbutrin@) from incubations with human liver S9 fraction and human liver microsomes based on molecular weight information from full scan experiments using a liquid chromatograph coupled to a quadruple ion trap mass ...

Research paper thumbnail of The use of low-energy collisionally activated dissociation negative-ion tandem mass spectrometry for the characterization of dog and human urinary metabolites of the drug BW 1370U87

Rapid Communications in Mass Spectrometry, 1994

Liquid chromatography (LC) combined with atmospheric pressure chemical ionization mass spectromet... more Liquid chromatography (LC) combined with atmospheric pressure chemical ionization mass spectrometry was used to identify phase I and II metabolites of the drug BW 1370U87 in dog and human urine. Additional analysis of individual high-performance liquid chromatograph fractions collected from dog urine by combined gas chromatography/mass spectrometry identified one metabolite which was not detected by LC/MS methods. Using negative-ion LC/MS, the majority of BW 1370U87 metabolites in human urine were identified as glucuronic acid conjugates of phase I oxidative metabolites. The negative-ion fragmentation produced by low-energy collisionally activated decomposition (CAD), studied by tandem mass spectrometry experiments, confirmed that these compounds were drug-related and allowed metabolite structures to be assigned. Product-ion spectra of the metabolites were dominated by the loss of neutral molecules from even-electron deprotonated [M-H]- ions.

Research paper thumbnail of Quantitative-qualitative data acquisition using a benchtop orbitrap mass spectrometer

Journal of the American Society for Mass Spectrometry, 2009

Current approaches to discovery-stage drug metabolism studies (pharmacokinetics, microsomal stabi... more Current approaches to discovery-stage drug metabolism studies (pharmacokinetics, microsomal stability, etc.) typically use triple-quadrupole-based approaches for quantitative analysis. This necessitates the optimization of parameters such as Q1 and Q3 m/z values, collision energy, and interface voltages. These studies detect only the specified compound and information about other components, such as metabolites, is lost. The ability to perform full-scan acquisition for quantitative analysis would eliminate the need for compound optimization while enabling the detection of metabolites and other non-drug-related endogenous components. Such an instrument would have to provide sensitivity, selectivity, dynamic range, and scan speed suitable for discovery-stage quantitative studies. In this study, a prototype benchtop Orbitrap-based mass analyzer was used to collect both quantitative and qualitative data from human microsomal incubation samples as well as rat plasma from pharmacokinetic studies. Instrumental parameters such as scan speed, resolution, and mass accuracy are discussed in relation to the requirements for a quantitativequalitative workflow. The ability to perform highly selective quantitative analysis while simultaneously characterizing metabolites from both in vitro and in vivo studies is discussed. (J Am Soc

Research paper thumbnail of Tetranuclear carbidotungsten and nitridomolybdenum clusters supported by alkoxide ligands: W4(C)(OCHMe2)12(NMe) and Mo4(N)2(OCHMe2)12

Journal of the American Chemical Society, 1985

DHHS. We are grateful for their continued support of our re-search. Partial support from the Alfr... more DHHS. We are grateful for their continued support of our re-search. Partial support from the Alfred P. Sloan Foundation in the form of a fellowship to RDL is also gratefully acknowledged. ... Supplementary Material Available: Full X-ray data and per-spective views of the molecular structure for ...

Research paper thumbnail of Characterization of Monoclonal Antibody Glycosylation: Comparison of Expression Systems and Identification of Terminal α-Linked Galactose

Analytical Biochemistry, 1997

CAMPATH-1H is a recombinant humanized murine monoclonal immunoglobulin (IgG 1 ) which recognizes ... more CAMPATH-1H is a recombinant humanized murine monoclonal immunoglobulin (IgG 1 ) which recognizes the CDw52 antigen of human lymphocytes, and has been the subject of clinical trials for the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis. Peptide mapping ...

Research paper thumbnail of Plenary Lecture: Speaker invited by the 2008 Gold Sponsor (Thermo Scientific) "Full scan data acquisition for rapid quantitative and qualitative analysis using a bench-top non-hybrid ESI-Orbitrap mass spectrometer

Markus Kellmann3; Philip Tiller4; Robert Papp1; Lester C. Taylor3 1Merck Frosst, Montreal, QC; 2T... more Markus Kellmann3; Philip Tiller4; Robert Papp1; Lester C. Taylor3 1Merck Frosst, Montreal, QC; 2Thermo Fisher Scientific (bremen) Gmbh, Bremen, GERMANY; 3Thermo Fisher

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