1
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Bishop J, Rogachev GV, Ahn S, Barbui M, Cha SM, Harris E, Hunt C, Kim CH, Kim D, Kim SH, Koshchiy E, Luo Z, Park C, Parker CE, Pollacco EC, Roeder BT, Roosa M, Saastamoinen A, Scriven DP. First Observation of the β3αp Decay of ^{13}O via β-Delayed Charged-Particle Spectroscopy. Phys Rev Lett 2023; 130:222501. [PMID: 37327448 DOI: 10.1103/physrevlett.130.222501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/25/2023] [Accepted: 05/11/2023] [Indexed: 06/18/2023]
Abstract
The β-delayed proton decay of ^{13}O has previously been studied, but the direct observation of β-delayed 3αp decay has not been reported. Rare 3αp events from the decay of excited states in ^{13}N^{⋆} provide a sensitive probe of cluster configurations in ^{13}N. To measure the low-energy products following β-delayed 3αp decay, the Texas Active Target (TexAT) time projection chamber was employed using the one-at-a-time β-delayed charged-particle spectroscopy technique at the Cyclotron Institute, Texas A&M University. A total of 1.9×10^{5} ^{13}O implantations were made inside the TexAT time projection chamber. A total of 149 3αp events were observed, yielding a β-delayed 3αp branching ratio of 0.078(6)%. Four previously unknown α-decaying excited states were observed in ^{13}N at 11.3, 12.4, 13.1, and 13.7 MeV decaying via the 3α+p channel.
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Affiliation(s)
- J Bishop
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - G V Rogachev
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
- Nuclear Solutions Institute, Texas A&M University, College Station, Texas 77843, USA
| | - S Ahn
- Center for Exotic Nuclear Studies, Institute for Basic Science, 34126 Daejeon, Republic of Korea
| | - M Barbui
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - S M Cha
- Center for Exotic Nuclear Studies, Institute for Basic Science, 34126 Daejeon, Republic of Korea
| | - E Harris
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - C Hunt
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - C H Kim
- Department of Physics, Sungkyunkwan University (SKKU), Seoul 16419, Republic of Korea
| | - D Kim
- Center for Exotic Nuclear Studies, Institute for Basic Science, 34126 Daejeon, Republic of Korea
| | - S H Kim
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - E Koshchiy
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - Z Luo
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - C Park
- Center for Exotic Nuclear Studies, Institute for Basic Science, 34126 Daejeon, Republic of Korea
| | - C E Parker
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - E C Pollacco
- IRFU, CEA, Université Paris-Saclay, Gif-Sur-Yvette 91190, France
| | - B T Roeder
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - M Roosa
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
| | - A Saastamoinen
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
| | - D P Scriven
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA
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2
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Bishop J, Parker CE, Rogachev GV, Ahn S, Koshchiy E, Brandenburg K, Brune CR, Charity RJ, Derkin J, Dronchi N, Hamad G, Jones-Alberty Y, Kokalova T, Massey TN, Meisel Z, Ohstrom EV, Paneru SN, Pollacco EC, Saxena M, Singh N, Smith R, Sobotka LG, Soltesz D, Subedi SK, Voinov AV, Warren J, Wheldon C. Neutron-upscattering enhancement of the triple-alpha process. Nat Commun 2022; 13:2151. [PMID: 35444209 PMCID: PMC9021293 DOI: 10.1038/s41467-022-29848-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/31/2022] [Indexed: 11/30/2022] Open
Abstract
The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of 12C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO2 gas, we measure the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers). The triple-alpha process plays a role in nucleosynthesis, in the formation of 12C. Here, the authors discuss the rate and role of the neutron upscattering phenomenon on the triple-alpha process in a multi-step process.
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Affiliation(s)
- J Bishop
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA.
| | - C E Parker
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA
| | - G V Rogachev
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA.,Department of Physics & Astronomy, Texas A&M University, College Station, TX, 77843, USA.,Nuclear Solutions Institute, Texas A&M University, College Station, TX, 77843, USA
| | - S Ahn
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA.,Center for Exotic Nuclear Studies, Institute for Basic Science (IBS), Daejeon, 34126, Republic of Korea
| | - E Koshchiy
- Cyclotron Institute, Texas A&M University, College Station, TX, 77843, USA
| | - K Brandenburg
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - C R Brune
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - R J Charity
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA
| | - J Derkin
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - N Dronchi
- Department of Physics, Washington University, St. Louis, MO, 63130, USA
| | - G Hamad
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - Y Jones-Alberty
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - Tz Kokalova
- School of Physics and Astronomy, University of Birmingham, Birmingham, UK
| | - T N Massey
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - Z Meisel
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - E V Ohstrom
- Department of Physics, Washington University, St. Louis, MO, 63130, USA
| | - S N Paneru
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - E C Pollacco
- IRFU, CEA, Université Paris-Saclay, Gif-Sur-Yvette, France
| | - M Saxena
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - N Singh
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - R Smith
- Department of Engineering and Mathematics, Sheffield Hallam University, Sheffield, S1 1WB, UK
| | - L G Sobotka
- Department of Chemistry, Washington University, St. Louis, MO, 63130, USA.,Department of Physics, Washington University, St. Louis, MO, 63130, USA.,McDonnell Center for the Space Sciences, Washington University, St. Louis, MO, 63130, USA
| | - D Soltesz
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - S K Subedi
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - A V Voinov
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - J Warren
- Edwards Accelerator Laboratory, Department of Physics & Astronomy, Ohio University, Athens, OH, 45701, USA
| | - C Wheldon
- School of Physics and Astronomy, University of Birmingham, Birmingham, UK
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3
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Kabadi NV, Simpson R, Adrian PJ, Bose A, Frenje JA, Gatu Johnson M, Lahmann B, Li CK, Parker CE, Séguin FH, Sutcliffe GD, Petrasso RD, Atzeni S, Eriksson J, Forrest C, Fess S, Glebov VY, Janezic R, Mannion OM, Rinderknecht HG, Rosenberg MJ, Stoeckl C, Kagan G, Hoppe M, Luo R, Schoff M, Shuldberg C, Sio HW, Sanchez J, Hopkins LB, Schlossberg D, Hahn K, Yeamans C. Thermal decoupling of deuterium and tritium during the inertial confinement fusion shock-convergence phase. Phys Rev E 2021; 104:L013201. [PMID: 34412205 DOI: 10.1103/physreve.104.l013201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 06/23/2021] [Indexed: 11/07/2022]
Abstract
A series of thin glass-shell shock-driven DT gas-filled capsule implosions was conducted at the OMEGA laser facility. These experiments generate conditions relevant to the central plasma during the shock-convergence phase of ablatively driven inertial confinement fusion (ICF) implosions. The spectral temperatures inferred from the DTn and DDn spectra are most consistent with a two-ion-temperature plasma, where the initial apparent temperature ratio, T_{T}/T_{D}, is 1.5. This is an experimental confirmation of the long-standing conjecture that plasma shocks couple energy directly proportional to the species mass in multi-ion plasmas. The apparent temperature ratio trend with equilibration time matches expected thermal equilibration described by hydrodynamic theory. This indicates that deuterium and tritium ions have different energy distributions for the time period surrounding shock convergence in ignition-relevant ICF implosions.
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Affiliation(s)
- N V Kabadi
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - R Simpson
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - P J Adrian
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Bose
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J A Frenje
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - M Gatu Johnson
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - B Lahmann
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C K Li
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C E Parker
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - F H Séguin
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - G D Sutcliffe
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - R D Petrasso
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S Atzeni
- Dipartimento SBAI, Universit'a degli Studi di Roma "La Sapienza," Via Antonio Scarpa 14, 00161, Roma, Italy
| | - J Eriksson
- Department of Physics and Astronomy, Uppsala University, SE-752 37 Uppsala, Sweden
| | - C Forrest
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - S Fess
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - V Yu Glebov
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - R Janezic
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - O M Mannion
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - H G Rinderknecht
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - M J Rosenberg
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - C Stoeckl
- University of Rochester Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - G Kagan
- Centre for Inertial Fusion Studies, The Blackett Laboratory, Imperial College, London SW7 2AZ, United Kingdom
| | - M Hoppe
- General Atomics, San Diego, California 92121, USA
| | - R Luo
- General Atomics, San Diego, California 92121, USA
| | - M Schoff
- General Atomics, San Diego, California 92121, USA
| | - C Shuldberg
- General Atomics, San Diego, California 92121, USA
| | - H W Sio
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J Sanchez
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - L Berzak Hopkins
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D Schlossberg
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - K Hahn
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - C Yeamans
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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4
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Gatu Johnson M, Aguirre B, Armstrong J, Fooks JA, Forrest C, Frenje JA, Glebov VY, Hoppe M, Katz J, Knauer JP, Martin W, Parker CE, Reynolds HG, Schoff ME, Séguin FH, Sorce C, Sperry B, Stoeckl C, Petrasso RD. Using millimeter-sized carbon-deuterium foils for high-precision deuterium-tritium neutron spectrum measurements in direct-drive inertial confinement fusion at the OMEGA laser facility. Rev Sci Instrum 2021; 92:023503. [PMID: 33648107 DOI: 10.1063/5.0040549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
Millimeter-sized CD foils fielded close (order mm) to inertial confinement fusion (ICF) implosions have been proposed as a game-changer for improving energy resolution and allowing time-resolution in neutron spectrum measurements using the magnetic recoil technique. This paper presents results from initial experiments testing this concept for direct drive ICF at the OMEGA Laser Facility. While the foils are shown to produce reasonable signals, inferred spectral broadening is seen to be high (∼5 keV) and signal levels are low (by ∼20%) compared to expectation. Before this type of foil is used for precision experiments, the foil mount must be improved, oxygen uptake in the foils must be better characterized, and impact of uncontrolled foil motion prior to detection must be investigated.
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Affiliation(s)
- M Gatu Johnson
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - B Aguirre
- Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | - J Armstrong
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J A Fooks
- General Atomics, San Diego, California 92186, USA
| | - C Forrest
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J A Frenje
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - V Yu Glebov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - M Hoppe
- General Atomics, San Diego, California 92186, USA
| | - J Katz
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J P Knauer
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - W Martin
- Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | - C E Parker
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - H G Reynolds
- General Atomics, San Diego, California 92186, USA
| | - M E Schoff
- General Atomics, San Diego, California 92186, USA
| | - F H Séguin
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C Sorce
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - B Sperry
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R D Petrasso
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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5
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Istl AC, Yang M, Parker CE, Fleshner K, Guizzetti L, Jairath V. A125 PERIOPERATIVE ANTI-TNFα AGENTS AND POST-OPERATIVE INFECTIOUS COMPLICATIONS IN ELECTIVE SURGICAL IBD PATIENTS. J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A C Istl
- Western University, London, ON, Canada
| | - M Yang
- Western University, London, ON, Canada
| | - C E Parker
- Robarts Research Institute, London, ON, Canada
| | | | - L Guizzetti
- Robarts Research Institute, London, ON, Canada
| | - V Jairath
- Robarts Research Institute, London, ON, Canada
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6
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Murray A, Nguyen T, Parker CE, MacDonald JK, Feagan BG. A145 ORAL 5-ASA FOR INDUCTION AND MAINTENANCE OF REMISSION IN ULCERATIVE COLITIS. J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- A Murray
- Western University, London, ON, Canada
| | - T Nguyen
- Robarts Clinical Trials Inc, London, ON, Canada
| | - C E Parker
- Robarts Clinical Trials Inc, London, ON, Canada
| | - J K MacDonald
- Medicine, University of Western Ontario , London, ON, Canada
| | - B G Feagan
- Robarts Clinical Trials Inc, London, ON, Canada
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7
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Townsend CM, Cepek J, Abbass M, Nguyen T, Parker CE, MacDonald JK, Feagan BG, Jairath V, Khanna R. A96 ADALIMUMAB FOR MAINTENANCE OF REMISSION IN CROHN’S DISEASE. J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- C M Townsend
- Medicine, University of Western Ontario , London, ON, Canada
| | - J Cepek
- Robarts Clinical Trials Inc, London, ON, Canada
| | - M Abbass
- Robarts Clinical Trials Inc, London, ON, Canada
| | - T Nguyen
- Robarts Clinical Trials Inc, London, ON, Canada
| | - C E Parker
- Robarts Clinical Trials Inc, London, ON, Canada
| | | | - B G Feagan
- Robarts Clinical Trials Inc, London, ON, Canada
| | - V Jairath
- Robarts Clinical Trials Inc, London, ON, Canada
| | - R Khanna
- Robarts Clinical Trials Inc, London, ON, Canada
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8
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Sio H, Frenje JA, Le A, Atzeni S, Kwan TJT, Gatu Johnson M, Kagan G, Stoeckl C, Li CK, Parker CE, Forrest CJ, Glebov V, Kabadi NV, Bose A, Rinderknecht HG, Amendt P, Casey DT, Mancini R, Taitano WT, Keenan B, Simakov AN, Chacón L, Regan SP, Sangster TC, Campbell EM, Seguin FH, Petrasso RD. Observations of Multiple Nuclear Reaction Histories and Fuel-Ion Species Dynamics in Shock-Driven Inertial Confinement Fusion Implosions. Phys Rev Lett 2019; 122:035001. [PMID: 30735406 DOI: 10.1103/physrevlett.122.035001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/27/2018] [Indexed: 06/09/2023]
Abstract
Fuel-ion species dynamics in hydrodynamiclike shock-driven DT^{3}He-filled inertial confinement fusion implosion is quantitatively assessed for the first time using simultaneously measured D^{3}He and DT reaction histories. These reaction histories are measured with the particle x-ray temporal diagnostic, which captures the relative timing between different nuclear burns with unprecedented precision (∼10 ps). The observed 50±10 ps earlier D^{3}He reaction history timing (relative to DT) cannot be explained by average-ion hydrodynamic simulations and is attributed to fuel-ion species separation between the D, T, and ^{3}He ions during shock convergence and rebound. At the onset of the shock burn, inferred ^{3}He/T fuel ratio in the burn region using the measured reaction histories is much higher as compared to the initial gas-filled ratio. As T and ^{3}He have the same mass but different charge, these results indicate that the charge-to-mass ratio plays an important role in driving fuel-ion species separation during strong shock propagation even for these hydrodynamiclike plasmas.
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Affiliation(s)
- H Sio
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J A Frenje
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Atzeni
- Dipartimento SBAI, Università degli Studi di Roma "La Sapienza," Via Antonio Scarpa 14, 00161, Roma, Italy
| | - T J T Kwan
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M Gatu Johnson
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - G Kagan
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - C K Li
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C E Parker
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C J Forrest
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - V Glebov
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - N V Kabadi
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A Bose
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | - P Amendt
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - D T Casey
- Lawrence Livermore National Laboratory, Livermore, California 94551, USA
| | - R Mancini
- Physics Department, University of Nevada, Reno, Nevada, 89557, USA
| | - W T Taitano
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Keenan
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A N Simakov
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Chacón
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S P Regan
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - T C Sangster
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - E M Campbell
- Laboratory for Laser Energetics, Rochester, New York 14623, USA
| | - F H Seguin
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - R D Petrasso
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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9
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Parker CE, Frenje JA, Johnson MG, Schlossberg DJ, Reynolds HG, Hopkins LB, Bionta R, Casey DT, Felker SJ, Hilsabeck TJ, Kilkenny JD, Li CK, Mackinnon AJ, Robey H, Schoff ME, Séguin FH, Wink CW, Petrasso RD. Implementation of the foil-on-hohlraum technique for the magnetic recoil spectrometer for time-resolved neutron measurements at the National Ignition Facility. Rev Sci Instrum 2018; 89:113508. [PMID: 30501287 DOI: 10.1063/1.5052184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/02/2018] [Indexed: 06/09/2023]
Abstract
The next-generation Magnetic Recoil Spectrometer, called MRSt, will provide time-resolved measurements of the deuterium-tritium-neutron spectrum from inertial confinement fusion implosions at the National Ignition Facility. These measurements will provide critical information about the time evolution of the fuel assembly, hot-spot formation, and nuclear burn. The absolute neutron spectrum in the energy range of 12-16 MeV will be measured with high accuracy (∼5%), unprecedented energy resolution (∼100 keV) and, for the first time ever, time resolution (∼20 ps). Crucial to the design of the system is a CD conversion foil for the production of recoil deuterons positioned as close to the implosion as possible. The foil-on-hohlraum technique has been demonstrated by placing a 1-mm-diameter, 40-μm-thick CD foil on the hohlraum diagnostic band along the line-of-sight of the current time-integrated MRS system, which measured the recoil deuterons. In addition to providing validation of the foil-on-hohlraum technique for the MRSt design, substantial improvement of the MRS energy resolution has been demonstrated.
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Affiliation(s)
- C E Parker
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J A Frenje
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M Gatu Johnson
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - D J Schlossberg
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - H G Reynolds
- General Atomics, San Diego, California 92186, USA
| | - L Berzak Hopkins
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Bionta
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D T Casey
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S J Felker
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | | | - J D Kilkenny
- General Atomics, San Diego, California 92186, USA
| | - C K Li
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A J Mackinnon
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - H Robey
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M E Schoff
- General Atomics, San Diego, California 92186, USA
| | - F H Séguin
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C W Wink
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - R D Petrasso
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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10
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Gatu Johnson M, Katz J, Forrest C, Frenje JA, Glebov VY, Li CK, Paguio R, Parker CE, Robillard C, Sangster TC, Schoff M, Séguin FH, Stoeckl C, Petrasso RD. Measurement of apparent ion temperature using the magnetic recoil spectrometer at the OMEGA laser facility. Rev Sci Instrum 2018; 89:10I129. [PMID: 30399924 DOI: 10.1063/1.5035287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/05/2018] [Indexed: 06/08/2023]
Abstract
The Magnetic Recoil neutron Spectrometer (MRS) at the OMEGA laser facility has been routinely used to measure deuterium-tritium (DT) yield and areal density in cryogenically layered implosions since 2008. Recently, operation of the OMEGA MRS in higher-resolution mode with a new smaller, thinner (4 cm2, 57 μm thick) CD2 conversion foil has also enabled inference of the apparent DT ion temperature (T ion) from MRS data. MRS-inferred T ion compares well with T ion as measured using neutron time-of-flight spectrometers, which is important as it demonstrates good understanding of the very different systematics associated with the two independent measurements. The MRS resolution in this configuration, ΔE MRS = 0.91 MeV FWHM, is still higher than that required for a high-precision T ion measurement. We show how fielding a smaller foil closer to the target chamber center and redesigning the MRS detector array could bring the resolution to ΔE MRS = 0.45 MeV, reducing the systematic T ion uncertainty by more than a factor of 4.
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Affiliation(s)
- M Gatu Johnson
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J Katz
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C Forrest
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J A Frenje
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - V Yu Glebov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C K Li
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - R Paguio
- General Atomics, San Diego, California 92186, USA
| | - C E Parker
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C Robillard
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - T C Sangster
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - M Schoff
- General Atomics, San Diego, California 92186, USA
| | - F H Séguin
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R D Petrasso
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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11
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Ma C, Dutton SJ, Cipriano LE, Singh S, Parker CE, Nguyen TM, Guizzetti L, Gregor JC, Chande N, Hindryckx P, Feagan BG, Jairath V. Systematic review with meta-analysis: prevalence, risk factors and costs of aminosalicylate use in Crohn's disease. Aliment Pharmacol Ther 2018; 48:114-126. [PMID: 29851091 DOI: 10.1111/apt.14821] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 04/13/2018] [Accepted: 05/02/2018] [Indexed: 12/22/2022]
Abstract
BACKGROUND Aminosalicylates are the most frequently prescribed drugs for patients with Crohn's disease (CD), yet evidence to support their efficacy as induction or maintenance therapy is controversial. AIMS To quantify aminosalicylate use in CD clinical trials, identify factors associated with use and estimate direct annual treatment costs of therapy. METHODS MEDLINE, Embase and CENTRAL were searched to April 2017 for placebo-controlled trials in adults with CD treated with corticosteroids, immunosuppressants or biologics. The proportion of patients co-prescribed aminosalicylates in placebo arms was pooled using a random-effects model. Meta-regression was used to identify factors associated with aminosalicylate use. Annual treatment costs were estimated using the 2016 Ontario Drug Benefit Program. RESULTS Forty-two induction and 10 maintenance trials were included. The pooled proportion of patients co-prescribed aminosalicylates was 44% [95% CI: 39%-49%] in induction trials and 49% [95% CI: 35%-64%] in maintenance trials. There was substantial to considerable heterogeneity (I2 = 86.0%, 91.8% for induction and maintenance trials, respectively). In multivariable meta-regression, aminosalicylate use has decreased over time in induction trials (OR 0.50 [95% CI: 0.34-0.74] per 10-year increment). While a decline has been seen over time, 35% of CD patients were still using aminosalicylates in contemporary trials from the last 5 years. The estimated annual cost for the lowest price mesalazine (mesalamine) formulation is approximately $32 million for the Canadian CD population. CONCLUSIONS Over one-third of CD patients entering clinical trials are still co-prescribed aminosalicylates. A definitive trial is needed to inform the conventional practice of using aminosalicylates as CD maintenance therapy.
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Affiliation(s)
- C Ma
- Division of Gastroenterology and Hepatology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Robarts Clinical Trials, Western University, London, ON, Canada
| | - S J Dutton
- Oxford Clinical Trials Research Unit and Centre for Statistics in Medicine, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - L E Cipriano
- Department of Epidemiology and Biostatistics, Western University, London, ON, Canada.,Ivey Business School, Western University, London, ON, Canada
| | - S Singh
- Division of Biomedical Informatics, University of California San Diego, La Jolla, CA, USA.,Division of Gastroenterology, University of California San Diego, La Jolla, CA, USA
| | - C E Parker
- Robarts Clinical Trials, Western University, London, ON, Canada
| | - T M Nguyen
- Robarts Clinical Trials, Western University, London, ON, Canada
| | - L Guizzetti
- Robarts Clinical Trials, Western University, London, ON, Canada
| | - J C Gregor
- Division of Gastroenterology, Department of Medicine, Western University, London, ON, Canada
| | - N Chande
- Division of Gastroenterology, Department of Medicine, Western University, London, ON, Canada
| | - P Hindryckx
- Department of Gastroenterology, University Hospital of Ghent, Ghent, Belgium
| | - B G Feagan
- Robarts Clinical Trials, Western University, London, ON, Canada.,Department of Epidemiology and Biostatistics, Western University, London, ON, Canada.,Division of Gastroenterology, Department of Medicine, Western University, London, ON, Canada
| | - V Jairath
- Robarts Clinical Trials, Western University, London, ON, Canada.,Department of Epidemiology and Biostatistics, Western University, London, ON, Canada.,Division of Gastroenterology, Department of Medicine, Western University, London, ON, Canada
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12
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Ma C, Guizzetti L, Panaccione R, Fedorak RN, Pai RK, Parker CE, Nguyen TM, Khanna R, Vande Casteele N, D'Haens G, Sandborn WJ, Feagan BG, Jairath V. Systematic review with meta-analysis: endoscopic and histologic placebo rates in induction and maintenance trials of ulcerative colitis. Aliment Pharmacol Ther 2018; 47:1578-1596. [PMID: 29696670 DOI: 10.1111/apt.14672] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/17/2018] [Accepted: 03/27/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Regulatory requirements for claims of mucosal healing in ulcerative colitis (UC) will require demonstration of both endoscopic and histologic healing. Quantifying these rates is essential for future drug development. AIMS To meta-analyse endoscopic and histologic placebo response and remission rates in UC randomised controlled trials (RCTs) and identify factors influencing these rates. METHODS MEDLINE, EMBASE and the Cochrane Library were searched from inception to March 2017 for placebo-controlled trials of pharmacological interventions for UC. Endoscopic and histologic placebo rates were pooled by random effects. Mixed effects univariable and multivariable meta-regression was used to evaluate the influence of patient, intervention and trial-related study-level covariates on these rates. RESULTS Fifty-six induction (placebo n = 4171) and 8 maintenance trials (placebo n = 1011) were included. Pooled placebo endoscopic remission and response rates for induction trials were 23% [95 confidence interval (CI) 19-28%] and 35% [95% CI 27-42%] respectively, and 20% [95% CI 16-24%] for maintenance of remission. The pooled histologic placebo remission rate was 14% [95% CI 8-22%] for induction trials. High heterogeneity was observed for all outcomes (I2 56.2%-88.3%). On multivariable meta-regression, central endoscopy reading was associated with significantly lower endoscopic placebo remission rates (16% vs 25%; OR = 0.52, [95% CI 0.29-0.92], P = 0.03). On univariable meta-regression, higher histologic placebo remission was associated with concomitant corticosteroids (OR = 1.17 [95% CI 1.08-1.26], P < 0.0001, per 10% increase in corticosteroid use). CONCLUSIONS Placebo endoscopic and histologic rates range from 14% to 35% in UC RCTs but are highly heterogeneous. Outcome standardisation may reduce heterogeneity and is needed in this field.
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Affiliation(s)
- C Ma
- Division of Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada.,Robarts Clinical Trials, Western University, London, ON, Canada
| | - L Guizzetti
- Robarts Clinical Trials, Western University, London, ON, Canada
| | - R Panaccione
- Division of Gastroenterology and Hepatology, University of Calgary, Calgary, AB, Canada
| | - R N Fedorak
- Division of Gastroenterology, University of Alberta, Edmonton, AB, Canada
| | - R K Pai
- Robarts Clinical Trials, Western University, London, ON, Canada.,Department of Pathology and Laboratory Medicine, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - C E Parker
- Robarts Clinical Trials, Western University, London, ON, Canada
| | - T M Nguyen
- Robarts Clinical Trials, Western University, London, ON, Canada
| | - R Khanna
- Robarts Clinical Trials, Western University, London, ON, Canada.,Department of Medicine, Western University, London, ON, Canada
| | - N Vande Casteele
- Robarts Clinical Trials, Western University, London, ON, Canada.,Division of Gastroenterology, University of California San Diego, La Jolla, CA, USA
| | - G D'Haens
- Robarts Clinical Trials, Western University, London, ON, Canada.,Inflammatory Bowel Disease Centre, Academic Medical Centre, Amsterdam, The Netherlands
| | - W J Sandborn
- Robarts Clinical Trials, Western University, London, ON, Canada.,Division of Gastroenterology, University of California San Diego, La Jolla, CA, USA
| | - B G Feagan
- Robarts Clinical Trials, Western University, London, ON, Canada.,Department of Medicine, Western University, London, ON, Canada.,Department of Epidemiology and Biostatistics, Western University, London, ON, Canada
| | - V Jairath
- Robarts Clinical Trials, Western University, London, ON, Canada.,Department of Medicine, Western University, London, ON, Canada.,Department of Epidemiology and Biostatistics, Western University, London, ON, Canada
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13
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Warners MJ, Ambarus CA, Bredenoord AJ, Verheij J, Lauwers GY, Walsh JC, Katzka DA, Nelson S, van Viegen T, Furuta GT, Gupta SK, Stitt L, Zou G, Parker CE, Shackelton LM, D Haens GR, Sandborn WJ, Dellon ES, Feagan BG, Collins MH, Jairath V, Pai RK. Reliability of histologic assessment in patients with eosinophilic oesophagitis. Aliment Pharmacol Ther 2018; 47:940-950. [PMID: 29460418 DOI: 10.1111/apt.14559] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 01/21/2018] [Accepted: 01/21/2018] [Indexed: 01/13/2023]
Abstract
BACKGROUND The validity of the eosinophilic oesophagitis (EoE) histologic scoring system (EoEHSS) has been demonstrated, but only preliminary reliability data exist. AIM Formally assess the reliability of the EoEHSS and additional histologic features. METHODS Four expert gastrointestinal pathologists independently reviewed slides from adult patients with EoE (N = 45) twice, in random order, using standardised training materials and scoring conventions for the EoEHSS and additional histologic features agreed upon during a modified Delphi process. Intra- and inter-rater reliability for scoring the EoEHSS, a visual analogue scale (VAS) of overall histopathologic disease severity, and additional histologic features were assessed using intra-class correlation coefficients (ICCs). RESULTS Almost perfect intra-rater reliability was observed for the composite EoEHSS scores and the VAS. Inter-rater reliability was also almost perfect for the composite EoEHSS scores and substantial for the VAS. Of the EoEHSS items, eosinophilic inflammation was associated with the highest ICC estimates and consistent with almost perfect intra- and inter-rater reliability. With the exception of dyskeratotic epithelial cells and surface epithelial alteration, ICC estimates for the remaining EoEHSS items were above the benchmarks for substantial intra-rater, and moderate inter-rater reliability. Estimation of peak eosinophil count and number of lamina propria eosinophils were associated with the highest ICC estimates among the exploratory items. CONCLUSION The composite EoEHSS and most component items are associated with substantial reliability when assessed by central pathologists. Future studies should assess responsiveness of the score to change after a therapeutic intervention to facilitate its use in clinical trials.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - G R D Haens
- Amsterdam, The Netherlands.,London, ON, Canada
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14
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Deol N, Nguyen T, Parker CE, Khanna R, MacDonald J, Feagan BG, Jairath V. A111 INFLIXIMAB FOR INDUCTION OF REMISSION IN CROHN’S DISEASE. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy008.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- N Deol
- Gastroenterology, Western University, London, ON, Canada
| | - T Nguyen
- Robarts Clinical Trials, London, ON, Canada
| | | | - R Khanna
- Department of Medicine, London, ON, Canada
| | | | - B G Feagan
- Department of Medicine, London, ON, Canada
| | - V Jairath
- Department of Medicine, London, ON, Canada
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15
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Ma C, Guizzetti L, Panaccione R, Fedorak R, Parker CE, Nguyen T, Khanna R, Feagan BG, Jairath V. A114 SYSTEMATIC REVIEW AND META-ANALYSIS: ENDOSCOPIC AND HISTOLOGIC PLACEBO RATES IN INDUCTION AND MAINTENANCE TRIALS OF ULCERATIVE COLITIS. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy009.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- C Ma
- University of Calgary, Calgary, AB, Canada
| | | | | | - R Fedorak
- University of Alberta, Edmonton, AB, Canada
| | - C E Parker
- Robarts Clinical Trials, London, ON, Canada
| | - T Nguyen
- Robarts Clinical Trials, London, ON, Canada
| | - R Khanna
- Western University, London, AB, Canada
| | | | - V Jairath
- Western University, London, AB, Canada
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16
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Yuly M, Eckert T, Hartshaw G, Padalino SJ, Polsin DN, Russ M, Simone AT, Brune CR, Massey TN, Parker CE, Fitzgerald R, Sangster TC, Regan SP. The 12C(n, 2n) 11C cross section from threshold to 26.5 MeV. Phys Rev C 2018; 97:024613. [PMID: 29732443 PMCID: PMC5930386 DOI: 10.1103/physrevc.97.024613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The 12C(n, 2n)11C cross section was measured from just below threshold to 26.5 MeV using the Pelletron accelerator at Ohio University. Monoenergetic neutrons, produced via the 3H(d,n)4He reaction, were allowed to strike targets of polyethylene and graphite. Activation of both targets was measured by counting positron annihilations resulting from the β+ decay of 11C. Annihilation gamma rays were detected, both in coincidence and singly, using back-to-back NaI detectors. The incident neutron flux was determined indirectly via 1H(n,p) protons elastically scattered from the polyethylene target. Previous measurements fall into upper and lower bands; the results of the present measurement are consistent with the upper band.
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Affiliation(s)
- M Yuly
- Department of Physics, Houghton College, Houghton, New York 14744, USA
| | - T Eckert
- Department of Physics, Houghton College, Houghton, New York 14744, USA
| | - G Hartshaw
- Department of Physics, Houghton College, Houghton, New York 14744, USA
| | - S J Padalino
- Department of Physics, State University of New York, Geneseo, New York 14454, USA
| | - D N Polsin
- Department of Physics, State University of New York, Geneseo, New York 14454, USA
| | - M Russ
- Department of Physics, State University of New York, Geneseo, New York 14454, USA
| | - A T Simone
- Department of Physics, State University of New York, Geneseo, New York 14454, USA
| | - C R Brune
- Edwards Accelerator Laboratory, Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - T N Massey
- Edwards Accelerator Laboratory, Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - C E Parker
- Edwards Accelerator Laboratory, Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - R Fitzgerald
- National Institute of Standards and Technology, 100 Bureau Drive, Stop 8462, Gaithersburg, Maryland 20899-8462, USA
| | - T C Sangster
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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17
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D'Haens GR, Sandborn WJ, Zou G, Stitt LW, Rutgeerts PJ, Gilgen D, Jairath V, Hindryckx P, Shackelton LM, Vandervoort MK, Parker CE, Muller C, Pai RK, Levchenko O, Marakhouski Y, Horynski M, Mikhailova E, Kharchenko N, Pimanov S, Feagan BG. Randomised non-inferiority trial: 1600 mg versus 400 mg tablets of mesalazine for the treatment of mild-to-moderate ulcerative colitis. Aliment Pharmacol Ther 2017; 46:292-302. [PMID: 28568974 DOI: 10.1111/apt.14164] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/16/2017] [Accepted: 05/04/2017] [Indexed: 12/11/2022]
Abstract
BACKGROUND High concentration mesalazine formulations are more convenient than conventional low concentration formulations for the treatment of ulcerative colitis (UC). AIM To compare the efficacy and safety of 1600 mg and 400 mg tablet mesalazine formulations. METHODS Patients with mild-to-moderate active UC (Mayo Clinic Score >5; N=817) were randomised to 3.2 g of oral mesalazine, administered as two 1600 mg tablets once, or four 400 mg tablets twice daily. We hypothesised that treatment with the 1600 mg tablet was non-inferior (within a 10% margin) to the 400 mg tablet for induction of clinical and endoscopic remission at week 8. Open-label treatment with the 1600 mg tablet continued for 26-30 weeks based on induction response. Predictors of treatment response were also explored. RESULTS At week 8, remission occurred in 22.4% and 24.6% of patients receiving the 1600 mg and 400 mg tablets, respectively (absolute difference -2.2%, 95% CI: -8.1% to 3.8%, non-inferiority P=.005). Endoscopic and histopathologic disease activity, leucocyte concentration and age were significantly associated with clinical remission (P=.022, .042, .014 and .023, respectively). At week 38, 43.9% (296/675) of patients who continued treatment with the 1600 mg formulation were in remission, including 70.3% (142/202) of patients who received a reduced dose of mesalazine (1.6 g/d). The overall incidence of serious adverse events was low. CONCLUSIONS Induction therapy with 3.2 mg mesalazine using two 1600 mg tablets once-daily was statistically and clinically non-inferior to a twice-daily regimen using four 400 mg tablets (NCT01903252).
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Affiliation(s)
- G R D'Haens
- Amsterdam, The Netherlands.,London, ON, Canada
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18
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Li H, Han J, Pan J, Liu T, Parker CE, Borchers CH. Current trends in quantitative proteomics - an update. J Mass Spectrom 2017; 52:319-341. [PMID: 28418607 DOI: 10.1002/jms.3932] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/28/2017] [Accepted: 04/06/2017] [Indexed: 05/11/2023]
Abstract
Proteins can provide insights into biological processes at the functional level, so they are very promising biomarker candidates. The quantification of proteins in biological samples has been routinely used for the diagnosis of diseases and monitoring the treatment. Although large-scale protein quantification in complex samples is still a challenging task, a great amount of effort has been made to advance the technologies that enable quantitative proteomics. Seven years ago, in 2009, we wrote an article about the current trends in quantitative proteomics. In writing this current paper, we realized that, today, we have an even wider selection of potential tools for quantitative proteomics. These tools include new derivatization reagents, novel sampling formats, new types of analyzers and scanning techniques, and recently developed software to assist in assay development and data analysis. In this review article, we will discuss these innovative methods, and their current and potential applications in proteomics. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- H Li
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, Victoria, BC, V8Z 7X8, Canada
| | - J Han
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, Victoria, BC, V8Z 7X8, Canada
| | - J Pan
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, Victoria, BC, V8Z 7X8, Canada
| | - T Liu
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, Victoria, BC, V8Z 7X8, Canada
| | - C E Parker
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, Victoria, BC, V8Z 7X8, Canada
| | - C H Borchers
- University of Victoria - Genome British Columbia Proteomics Centre, University of Victoria, Victoria, BC, V8Z 7X8, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8P 5C2, Canada
- Proteomics Centre, Segal Cancer Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, H3T 1E2, Canada
- Gerald Bronfman Department of Oncology, Jewish General Hospital, Montreal, Quebec, H3T 1E2, Canada
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19
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Jairath V, Zou G, Parker CE, MacDonald JK, Mosli MH, AlAmeel T, Al Beshir M, AlMadi M, Al-Taweel T, Atkinson NSS, Biswas S, Chapman TP, Dulai PS, Glaire MA, Hoekman D, Kherad O, Koutsoumpas A, Minas E, Restellini S, Samaan MA, Khanna R, Levesque BG, D'Haens G, Sandborn WJ, Feagan BG. Systematic review with meta-analysis: placebo rates in induction and maintenance trials of Crohn's disease. Aliment Pharmacol Ther 2017; 45:1021-1042. [PMID: 28164348 DOI: 10.1111/apt.13973] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 07/08/2016] [Accepted: 01/16/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Minimising placebo response is essential for drug development. AIM To conduct a meta-analysis to determine placebo response and remission rates in trials and identify the factors affecting these rates. METHODS MEDLINE, EMBASE and CENTRAL were searched from inception to April 2014 for placebo-controlled trials of pharmacological interventions for Crohn's disease. Placebo response and remission rates for induction and maintenance trials were pooled by random-effects and mixed-effects meta-regression models to evaluate effects of study-level characteristics on these rates. RESULTS In 100 studies containing 67 induction and 40 maintenance phases and 7638 participants, pooled placebo remission and response rates for induction trials were 18% [95% confidence interval (CI) 16-21%] and 28% (95% CI 24-32%), respectively. Corresponding values for maintenance trials were 32% (95% CI 25-39%) and 26% (95% CI 19-35%), respectively. For remission, trials enrolling patients with more severe disease activity, longer disease duration and more study centres were associated with lower placebo rates, whereas more study visits and longer study duration was associated with higher placebo rates. For response, findings were opposite such that trials enrolling patients with less severe disease activity and longer study duration were associated with lower placebo rates. Placebo rates varied by drug class and route of administration, with the highest placebo response rates observed for biologics. CONCLUSIONS Placebo rates vary according to whether trials are designed for induction or maintenance and the factors influencing them differ for the endpoints of remission and response. These findings have important implications for clinical trial design in Crohn's disease.
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Affiliation(s)
| | | | | | | | - M H Mosli
- London, ON, Canada.,Jeddah, Saudi Arabia
| | | | | | | | | | | | | | | | - P S Dulai
- London, ON, Canada.,La Jolla, CA, USA
| | | | | | | | | | | | | | | | | | | | - G D'Haens
- London, ON, Canada.,Amsterdam, The Netherlands
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20
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Gill MD, Bramble MG, Hull MA, Mills SJ, Morris E, Bradburn DM, Bury Y, Parker CE, Lee TJW, Rees CJ. Screen-detected colorectal cancers are associated with an improved outcome compared with stage-matched interval cancers. Br J Cancer 2014; 111:2076-81. [PMID: 25247322 PMCID: PMC4260027 DOI: 10.1038/bjc.2014.498] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Revised: 07/19/2014] [Accepted: 08/16/2014] [Indexed: 12/28/2022] Open
Abstract
Background: Colorectal cancers (CRCs) detected through the NHS Bowel Cancer Screening Programme (BCSP) have been shown to have a more favourable outcome compared to non-screen-detected cancers. The aim was to identify whether this was solely due to the earlier stage shift of these cancers, or whether other factors were involved. Methods: A combination of a regional CRC registry (Northern Colorectal Cancer Audit Group) and the BCSP database were used to identify screen-detected and interval cancers (diagnosed after a negative faecal occult blood test, before the next screening round), diagnosed between April 2007 and March 2010, within the North East of England. For each Dukes' stage, patient demographics, tumour characteristics, and survival rates were compared between these two groups. Results: Overall, 322 screen-detected cancers were compared against 192 interval cancers. Screen-detected Dukes' C and D CRCs had a superior survival rate compared with interval cancers (P=0.014 and P=0.04, respectively). Cox proportional hazards regression showed that Dukes' stage, tumour location, and diagnostic group (HR 0.45, 95% CI 0.29–0.69, P<0.001 for screen-detected CRCs) were all found to have a significant impact on the survival of patients. Conclusions: The improved survival of screen-detected over interval cancers for stages C and D suggest that there may be a biological difference in the cancers in each group. Although lead-time bias may have a role, this may be related to a tumour's propensity to bleed and therefore may reflect detection through current screening tests.
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Affiliation(s)
- M D Gill
- 1] Northern Colorectal Cancer Audit Group, North East England, UK [2] School of Medicine, Pharmacy and Health, University of Durham, Durham, UK [3] Northern Region Endoscopy Group, North East England, UK
| | - M G Bramble
- 1] School of Medicine, Pharmacy and Health, University of Durham, Durham, UK [2] Northern Region Endoscopy Group, North East England, UK
| | - M A Hull
- Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - S J Mills
- 1] Northern Colorectal Cancer Audit Group, North East England, UK [2] Northern Region Endoscopy Group, North East England, UK
| | - E Morris
- Leeds Institute of Cancer and Pathology, University of Leeds, Leeds, UK
| | - D M Bradburn
- 1] Northern Colorectal Cancer Audit Group, North East England, UK [2] Northern Region Endoscopy Group, North East England, UK
| | - Y Bury
- Royal Victoria Infirmary, Newcastle, UK
| | - C E Parker
- 1] Northern Region Endoscopy Group, North East England, UK [2] South Tyneside Foundation Trust, South Tyneside, UK
| | - T J W Lee
- 1] Northern Region Endoscopy Group, North East England, UK [2] North Tyneside General Hospital, Northumbria Healthcare NHS Foundation Trust, Northumberland, UK
| | - C J Rees
- 1] School of Medicine, Pharmacy and Health, University of Durham, Durham, UK [2] Northern Region Endoscopy Group, North East England, UK [3] South Tyneside Foundation Trust, South Tyneside, UK
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Parker CE, Degen GH, Abusteit EO, Corbin FT. The Determination of Metribuzin and Its Metabolites by High Pressure Liquid Chromatography. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/01483918308076080] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kadiiska MB, Gladen BC, Baird DD, Graham LB, Parker CE, Ames BN, Basu S, Fitzgerald GA, Lawson JA, Marnett LJ, Morrow JD, Murray DM, Plastaras J, Roberts LJ, Rokach J, Shigenaga MK, Sun J, Walter PB, Tomer KB, Barrett JC, Mason RP. Biomarkers of oxidative stress study III. Effects of the nonsteroidal anti-inflammatory agents indomethacin and meclofenamic acid on measurements of oxidative products of lipids in CCl4 poisoning. Free Radic Biol Med 2005; 38:711-8. [PMID: 15721981 DOI: 10.1016/j.freeradbiomed.2004.10.024] [Citation(s) in RCA: 310] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Accepted: 10/20/2004] [Indexed: 11/18/2022]
Abstract
Plasma and urinary levels of malondialdehyde-like products (MDA) and isoprostanes were identified as markers of in vivo lipid peroxidation in an animal model of CCl4 poisoning. We sought to determine the extent to which the formation of these oxidation products is influenced by inhibition of the cyclooxygenase enzymes which catalytically generate proinflammatory lipid peroxidation products known as prostaglandins and thromboxane. In the present studies, after induction of oxidant stress in rats with CCl4, lipid peroxidation products measured in plasma and urine demonstrate that isoprostanes and MDA can be partially inhibited by cyclooxygenase inhibitors, albeit to different extents. The lowering of isoprostane and MDA formation, however, may not to due primarily to the diminution of catalytic generation of isoprostanes or MDA by the cyclooxygenases but, rather, may be the result of the suppression of nonenzymatic lipid peroxidation. This is suggested since 8,12-iso-iPF2alpha-VI is also reduced by indomethacin, yet, unlike other isoprostanes and MDA, it is not generated catalytically by the cyclooxygenase. Thus, although the two cyclooxygenase inhibitors we tested have statistically significant effects on the measurements of both isoprostanes and MDA in this study, the results provide evidence that these lipid-degradation products primarily constitute markers of oxidative stress.
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Affiliation(s)
- M B Kadiiska
- National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA.
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Kadiiska MB, Gladen BC, Baird DD, Germolec D, Graham LB, Parker CE, Nyska A, Wachsman JT, Ames BN, Basu S, Brot N, Fitzgerald GA, Floyd RA, George M, Heinecke JW, Hatch GE, Hensley K, Lawson JA, Marnett LJ, Morrow JD, Murray DM, Plastaras J, Roberts LJ, Rokach J, Shigenaga MK, Sohal RS, Sun J, Tice RR, Van Thiel DH, Wellner D, Walter PB, Tomer KB, Mason RP, Barrett JC. Biomarkers of oxidative stress study II: are oxidation products of lipids, proteins, and DNA markers of CCl4 poisoning? Free Radic Biol Med 2005; 38:698-710. [PMID: 15721980 DOI: 10.1016/j.freeradbiomed.2004.09.017] [Citation(s) in RCA: 501] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Accepted: 09/20/2004] [Indexed: 12/20/2022]
Abstract
Oxidation products of lipids, proteins, and DNA in the blood, plasma, and urine of rats were measured as part of a comprehensive, multilaboratory validation study searching for noninvasive biomarkers of oxidative stress. This article is the second report of the nationwide Biomarkers of Oxidative Stress Study using acute CCl4 poisoning as a rodent model for oxidative stress. The time-dependent (2, 7, and 16 h) and dose-dependent (120 and 1200 mg/kg i.p.) effects of CCl4 on concentrations of lipid hydroperoxides, TBARS, malondialdehyde (MDA), isoprostanes, protein carbonyls, methionine sulfoxidation, tyrosine products, 8-hydroxy-2'-deoxyguanosine (8-OHdG), leukocyte DNA-MDA adducts, and DNA-strand breaks were investigated to determine whether the oxidative effects of CCl4 would result in increased generation of these oxidation products. Plasma concentrations of MDA and isoprostanes (both measured by GC-MS) and urinary concentrations of isoprostanes (measured with an immunoassay or LC/MS/MS) were increased in both low-dose and high-dose CCl4-treated rats at more than one time point. The other urinary markers (MDA and 8-OHdG) showed significant elevations with treatment under three of the four conditions tested. It is concluded that measurements of MDA and isoprostanes in plasma and urine as well as 8-OHdG in urine are potential candidates for general biomarkers of oxidative stress. All other products were not changed by CCl4 or showed fewer significant effects.
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Affiliation(s)
- M B Kadiiska
- Department of Health and Human Services, National Institute of Environmental Health Sciences, National Institutes of Health, P.O. Box 12233, MD F0-02, Research Triangle Park, NC 27709, USA.
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Hartman TJ, Baer DJ, Graham LB, Stone WL, Gunter EW, Parker CE, Albert PS, Dorgan JF, Clevidence BA, Campbell WS, Tomer KB, Judd JT, Taylor PR. Moderate alcohol consumption and levels of antioxidant vitamins and isoprostanes in postmenopausal women. Eur J Clin Nutr 2004; 59:161-8. [PMID: 15367922 DOI: 10.1038/sj.ejcn.1602051] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Although alcohol intake has been positively associated with breast cancer risk in epidemiologic studies, the mechanisms mediating this association are speculative. OBJECTIVE The Postmenopausal Women's Alcohol Study was designed to explore the effects of moderate alcohol consumption on potential risk factors for breast cancer. In the present analysis, we evaluated the relationship of alcohol consumption with antioxidant nutrients and a biomarker of oxidative stress. DESIGN Participants (n=53) consumed a controlled diet plus each of three treatments (15 or 30 g alcohol/day or a no-alcohol placebo beverage), during three 8-week periods in random order. We measured the antioxidants, vitamin E (alpha (alpha)- and gamma (gamma)-tocopherols), selenium, and vitamin C in fasting blood samples which were collected at the end of diet periods, treated and frozen for assay at the end of the study. We also measured 15-F(2t)-IsoP isoprostane, produced by lipid peroxidation, which serves as an indicator of oxidative stress and may serve as a biomarker for conditions favorable to carcinogenesis. RESULTS After adjusting for BMI (all models) and total serum cholesterol (tocopherol and isoprostane models) we observed a significant 4.6% decrease (P=0.02) in alpha-tocopherol and a marginally significant 4.9% increase (P=0.07) in isoprostane levels when women consumed 30 g alcohol/day (P=0.06 and 0.05 for overall effect of alcohol on alpha-tocopherol and isoprostanes, respectively). The other antioxidants were not significantly modified by the alcohol treatment. CONCLUSIONS These results suggest that moderate alcohol consumption increases some biomarkers of oxidative stress in postmenopausal women.
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Affiliation(s)
- T J Hartman
- Pennsylvania State University, University Park, PA 16802, USA.
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25
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Parker CE, Deterding LJ, Hager-Braun C, Binley JM, Schülke N, Katinger H, Moore JP, Tomer KB. Fine definition of the epitope on the gp41 glycoprotein of human immunodeficiency virus type 1 for the neutralizing monoclonal antibody 2F5. J Virol 2001; 75:10906-11. [PMID: 11602730 PMCID: PMC114670 DOI: 10.1128/jvi.75.22.10906-10911.2001] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2001] [Accepted: 08/13/2001] [Indexed: 11/20/2022] Open
Abstract
Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), in combination with proteolytic protection assays, has been used to identify the functional epitope on human immunodeficiency virus envelope glycoprotein gp41 for the broadly neutralizing anti-gp41 human monoclonal antibody 2F5. In this protection assay-based procedure, a soluble gp140 protein with a stabilizing intermolecular disulfide bond between the gp120 and gp41 subunits (SOS gp140) was affinity bound to immobilized 2F5 under physiological conditions. A combination of proteolytic enzymatic cleavages was then performed to remove unprotected residues. Residues of SOS gp140 protected by their binding to 2F5 were then identified based on their molecular weights as determined by direct MALDI-MS of the immobilized antibody beads. The epitope, NEQELLELDKWASLWN, determined by this MALDI-MS protection assay approach consists of 16 amino acid residues near the C terminus of gp41. It is significantly longer than the ELDKWA core epitope previously determined for 2F5 by peptide enzyme-linked immunosorbent assay. This new knowledge of the structure of the 2F5 epitope may facilitate the design of vaccine antigens intended to induce antibodies with the breadth and potency of action of the 2F5 monoclonal antibody.
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Affiliation(s)
- C E Parker
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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26
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Qu W, Bradbury JA, Tsao CC, Maronpot R, Harry GJ, Parker CE, Davis LS, Breyer MD, Waalkes MP, Falck JR, Chen J, Rosenberg RL, Zeldin DC. Cytochrome P450 CYP2J9, a new mouse arachidonic acid omega-1 hydroxylase predominantly expressed in brain. J Biol Chem 2001; 276:25467-79. [PMID: 11328810 DOI: 10.1074/jbc.m100545200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A cDNA encoding a new cytochrome P450 was isolated from a mouse brain library. Sequence analysis reveals that this 1,958-base pair cDNA encodes a 57-58-kDa 502-amino acid polypeptide that is 70-91% identical to CYP2J subfamily P450s and is designated CYP2J9. Recombinant CYP2J9 was co-expressed with NADPH-cytochrome P450 oxidoreductase (CYPOR) in Sf9 cells using a baculovirus system. Microsomes of CYP2J9/CYPOR-transfected cells metabolize arachidonic acid to 19-hydroxyeicosatetraenoic acid (HETE) thus CYP2J9 is enzymologically distinct from other P450s. Northern analysis reveals that CYP2J9 transcripts are present at high levels in mouse brain. Mouse brain microsomes biosynthesize 19-HETE. RNA polymerase chain reaction analysis demonstrates that CYP2J9 mRNAs are widely distributed in brain and most abundant in the cerebellum. Immunoblotting using an antibody raised against human CYP2J2 that cross-reacts with CYP2J9 detects a 56-kDa protein band that is expressed in cerebellum and other brain segments and is regulated during postnatal development. In situ hybridization of mouse brain sections with a CYP2J9-specific riboprobe and immunohistochemical staining with the anti-human CYP2J2 IgG reveals abundant CYP2J9 mRNA and protein in cerebellar Purkinje cells. Importantly, 19-HETE inhibits the activity of recombinant P/Q-type Ca(2+) channels that are known to be expressed preferentially in cerebellar Purkinje cells and are involved in triggering neurotransmitter release. Based on these data, we conclude that CYP2J9 is a developmentally regulated P450 that is abundant in brain, localized to cerebellar Purkinje cells, and active in the biosynthesis of 19-HETE, an eicosanoid that inhibits activity of P/Q-type Ca(2+) channels. We postulate that CYP2J9 arachidonic acid products play important functional roles in the brain.
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Affiliation(s)
- W Qu
- Division of Intramural Research, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
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Parker CE, Graham LB, Nguyen MN, Gladen BC, Kadiiska MB, Barrett JC, Tomer KB. An improved GC/MS-based procedure for the quantitation of the isoprostane 15-F2t-IsoP in rat plasma. Mol Biotechnol 2001; 18:105-18. [PMID: 11471453 DOI: 10.1385/mb:18:2:105] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This article describes a procedure for the quantitation of the isoprostane 15-F2t-IsoP (9a,11a,15S-trihydroxy-(8b)-prosta-5Z,13E-dien-1-oic acid [CAS#27415-26-5] formerly known as 8-epi-PGF2a or 8-iso-PGF2a, and also as iPF2a-III). We have combined features from several earlier methods for 15-F2t-IsoP and prostaglandins, and identified and modified those steps that may lead to poor recoveries. The resulting protocol is precise and reliable, and was validated by a blind time-course study of plasma levels in rats treated with 120 and 1200 mg CCl4/kg body weight. Plasma levels of 15-F2t-IsoP, as measured according to the procedure described above, are good indicators of acute oxidative stress as induced by CCl4. The precision of the measurements allows detection of elevated plasma 15-F2t-IsoP levels as long as 16 h after an acute exposure of 120 mg CCl4/kg body weight, and 2 h after an exposure of 1 mg CCl4/kg body weight. The results of this low-dose, pilot study suggest that this method has sufficient analytical precision to allow the detection of the small changes in plasma isoprostane levels, which result from chronic and/or lower-level exposures to agents causing oxidative stress.
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Affiliation(s)
- C E Parker
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
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Merrick BA, Zhou W, Martin KJ, Jeyarajah S, Parker CE, Selkirk JK, Tomer KB, Borchers CH. Site-specific phosphorylation of human p53 protein determined by mass spectrometry. Biochemistry 2001; 40:4053-66. [PMID: 11300786 DOI: 10.1021/bi002045i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human recombinant p53 (r-p53) protein was studied by mass spectrometry (MS) to determine site-specific posttranslational differences between basal and hyperphosphorylated r-p53. Wild-type p53 was basally expressed after baculovirus infection while a parallel preparation was treated with the phosphatase inhibitor okadaic acid during the terminal stages of expression to create a hyperphosphorylated form of p53 known for its higher DNA binding and transcriptional activation. After immunoaffinity and HPLC purification, MALDI/MS measured a higher molecular mass for r-p53 from okadaic acid treatment relative to control, suggesting a higher phosphorylation state. This was supported by an acidic shift of r-p53 isoforms separated by gel isoelectric focusing. Employing a variety of mass spectrometric analyses combined with separation and affinity techniques, six specific phosphorylation sites of p53 were identified. The MS data indicated that hyperphosphorylated p53 showed a higher degree of phosphorylation than basal p53 at specific amino- and carboxy-terminal sites. In particular, ESI-MS demonstrated that Ser(315) was entirely phosphorylated after okadaic acid treatment, as confirmed biochemically by CDK2 kinase assay and by isoelectric focusing. In summary, MS analysis uniquely revealed increased, site-specific phosphorylations on p53 after phosphatase inhibition, particularly at Ser(315), which may be critical molecular events in defining p53 activity.
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Affiliation(s)
- B A Merrick
- Laboratory of Molecular Carcinogenesis and Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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29
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Affiliation(s)
- C E Parker
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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Borchers C, Parker CE, Deterding LJ, Tomer KB. Preliminary comparison of precursor scans and liquid chromatography-tandem mass spectrometry on a hybrid quadrupole time-of-flight mass spectrometer. J Chromatogr A 1999; 854:119-30. [PMID: 10497933 DOI: 10.1016/s0021-9673(99)00479-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recent mass spectrometry instrumentation developments include the appearance of novel hybrid tandem instrumentation, Q-TOF, consisting of a quadrupole mass analyzer (MS1) and a time-of-flight (TOF) analyzer. The TOF analyzer is not scanned, but collects all fragment ions entering the analyzer at a given time. Thus, the typical precursor scan experiment cannot be performed. Instead, a full MS-MS spectrum can be acquired for each mass passed by MS1. Appropriate data manipulation, i.e. extracted ion current chromatograms, can correlate specific fragment ion formation to the parent ion. Precursor scanning and LC-MS-MS are compared on a Q-TOF instrument for the determination of protein modifications, including acetylation and phosphorylation. Model peptides used for phosphopeptide detection were generated from a mixture of beta-casein. Model acetylated peptides were generated from a mixture of acetylated substance P1-9 and substance P1-11. The results were then applied to a more complex mixture, a digest of HIV-p24. Results indicate that precursor scanning is useful for screening, but that LC-MS-MS has a sensitivity advantage and is less susceptible to suppression effects. LC-MS-MS, therefore, appears to be better for the detection of trace components in complex mixtures.
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Affiliation(s)
- C Borchers
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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31
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Jeyarajah S, Parker CE, Summer MT, Tomer KB. Matrix-assisted laser desorption ionization/mass spectrometry mapping of human immunodeficiency virus-gp120 epitopes recognized by a limited polyclonal antibody. J Am Soc Mass Spectrom 1998; 9:157-165. [PMID: 9679595 DOI: 10.1016/s1044-0305(97)00247-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In this study we have applied epitope excision and epitope extraction strategies, combined with matrix assisted laser desorption/ionization mass spectrometry, to determine the fine structure of epitopes recognized by a polyclonal antibody to human immunodeficiency virus envelope glycoprotein gp120. This is the first application of this approach to epitope mapping on a large, heavily glycosylated protein. In the epitope excision method, gp120 in the native form is first bound to the antibody immobilized on sepharose beads and cleaved with endoproteinase enzymes. In the epitope extraction method, the gp120 was first proteolytically cleaved and then allowed to react with the immobilized antibody. The fragments that remain bound to the antibody, after repeated washing to remove the unbound peptides, contain the antigenic region that is recognized by the antibody, and the bound peptides in both methods can be characterized by direct analysis of the immobilized antibody by matrix assisted laser desorption ionization/mass spectrometry. In this study we have carried out epitope excision and extraction experiments with three different enzymes and have identified residues 472-478 as a major epitope. In addition, antigenic regions containing minor epitopes have also been identified.
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Affiliation(s)
- S Jeyarajah
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, USA
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Affiliation(s)
- D J Stekel
- Dept of Zoology, University of Oxford, UK.
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Kurata JH, Nogawa AN, Chen YK, Parker CE. Dyspepsia in primary care: perceived causes, reasons for improvement, and satisfaction with care. J Fam Pract 1997; 44:281-288. [PMID: 9071248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
BACKGROUND While dyspepsia is a common problem in primary care populations, very little is known about patient perceptions of medical care for this disease. The present study of patients with dyspepsia treated by primary care physicians looks at causes, procedures, and reasons for improvement from the patient's viewpoint and relates these factors to patient satisfaction with family physicians' medical care. METHODS Medical chart and billing data were collected for 545 adult patients who visited five family health centers for digestive complaints during a 6-month period in 1993. A questionnaire was completed by 288 patients 6 to 8 weeks after patient's index visit. Baseline findings are reported. RESULTS The two most common causes of gastrointestinal problems were attributed to stress or anxiety (58%) and diet (46%). Between the time of the index visit and the baseline survey, 48% reported that they had recovered or improved. Of those who recovered or improved, most (75%) credited "taking GI medicine" followed by change in diet (44%). Patients who reported recovery or improvement of their gastrointestinal complaints (P < .001) and older patients (P = .032) were the most satisfied with overall medical care. Satisfaction with medical care was not associated with insurance coverage, procedures done, race, antiulcer medication treatment, diagnosis, general health status, or sex. CONCLUSIONS Specific health status, ie, improvement of gastrointestinal (GI) problems, predicted patient satisfaction for 70% of cases in this study. Most patients who improved credited GI medicines for their improvement, and those who improved were more satisfied with their medical care.
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Affiliation(s)
- J H Kurata
- San Bernardino County Medical Center, CA, USA
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Abstract
PURPOSE To determine the characteristics of patients developing retinal detachment secondary to retinal dialysis in Western Australia and to confirm the clinical impression that these patients had a low rate of proliferative vitreoretinopathy (PVR). METHODS A retrospective analysis of the records of 1601 consecutive patients with rhegmatogenous retinal detachment identified 71 patients in whom the retinal detachment was caused by a retinal dialysis. RESULTS The majority of these patients were young adults (mean age of 30 years) and the male to female ratio was 1.3:1. Seventy per cent of patients provided a history of significant trauma to the affected eye. Sporting injuries, assault, and motor vehicle injuries together accounted for 72% of identifiable trauma. Examination revealed a dialysis of the inferotemporal quadrant in 75% of cases and despite obvious signs of chronicity of the associated retinal detachment (such as intraretinal macrocysts and demarcation lines) in approximately one-third of the eyes, only 5.6% developed grade CI PVR either pre- or postoperatively. CONCLUSION The present study supports the view that it is the low rate of PVR that explains the good prognosis and high surgical success rate for retinal detachments caused by retinal dialysis. It is postulated that a major reason for the low rate of PVR is that the vitreous base attachment to the posterior margin of a retinal dialysis acts as a significant barrier to the migration of potentially proliferative retinal pigment epithelial cells. This may lead to containment of the responsible proliferative cells within the loculated subretinal space.
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Affiliation(s)
- C J Kennedy
- Lions Eye Institute, Nedlands, Western Australia, Australia
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35
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Odio A, Deamer RL, Cheadle M, Parker CE, Herbst M, Liu I, Amico M. A diagnostic cluster system for skilled nursing facilities. Fam Med 1996; 28:732-8. [PMID: 8937876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND OBJECTIVES Diagnostic cluster systems have been developed to assist in analyzing diagnoses in outpatient and inpatient settings but not in convalescent hospital settings. We developed a diagnostic cluster system for skilled nursing facilities (SNFs) designed to include or capture a greater proportion of such diagnoses than a previously established inpatient diagnostic cluster system. METHODS We tested the ability of the new SNF diagnostic cluster system to code diagnoses on records from SNFs in different geographic areas. Then we compared the proportion of admitting diagnoses captured by the new SNF diagnostic cluster system and by a previously established inpatient system. RESULTS The new diagnostic cluster system captured between 92% and 96% of admitting diagnoses at the study SNFs. There was no statistically significant difference among the facilities in the proportion of diagnoses captured by the new system. By comparison, the previously established inpatient system captured only 59%-65% of these admitting diagnoses. The new system captured significantly more diagnoses than the previously established inpatient system. CONCLUSIONS The new SNF diagnostic cluster system can be used to capture and code diagnostic data from SNFs.
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Affiliation(s)
- A Odio
- University of California, Los Angeles, USA
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36
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Iwahashi H, Deterding LJ, Parker CE, Mason RP, Tomer KB. Identification of radical adducts formed in the reactions of unsaturated fatty acids with soybean lipoxygenase using continuous flow fast atom bombardment with tandem mass spectrometry. Free Radic Res 1996; 25:255-74. [PMID: 8889492 DOI: 10.3109/10715769609149051] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Structures of alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) radical adducts formed in the reactions of soybean lipoxygenase with linoleic acid, linolenic acid, and arachidonic acid were determined using continuous flow fast atom bombardment (CF-FAB) combined with tandem mass spectrometry. The radical adducts of these lipoxygenase-dependent reactions were: n-octanoic acid radical, 12,13-dihydroxylinoleic acid radical, 12,13-epoxylinoleic acid radical, and n-pentyl radical from linoleic acid; n-octanoic acid radical, ethyl radical, and cis/trans and/or positional isomers (1- and 3-pentenyl) of pentenyl radical from linolenic acid; and 14,15-epoxyarachidonic acid radical and n-pentyl radical from arachidonic acid. Of these radical adducts, the n-octanoic acid radical from linoleic and linolenic acid, the ethyl radical from linolenic acid, and the 12,13-dihydroxylinoleic acid radical are identified for the first time in the reactions of soybean lipoxygenase. Thus the CF-FAB combined with tandem mass spectrometry employed here, by which both radical adducts and their fragment ions can be detected, is shown to be a powerful tool in the structural identification of free radicals.
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Affiliation(s)
- H Iwahashi
- Department of Chemistry, Wakayama Medical College, Japan
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37
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Kitareewan S, Burka LT, Tomer KB, Parker CE, Deterding LJ, Stevens RD, Forman BM, Mais DE, Heyman RA, McMorris T, Weinberger C. Phytol metabolites are circulating dietary factors that activate the nuclear receptor RXR. Mol Biol Cell 1996; 7:1153-66. [PMID: 8856661 PMCID: PMC275969 DOI: 10.1091/mbc.7.8.1153] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
RXR is a nuclear receptor that plays a central role in cell signaling by pairing with a host of other receptors. Previously, 9-cis-retinoic acid (9cRA) was defined as a potent RXR activator. Here we describe a unique RXR effector identified from organic extracts of bovine serum by following RXR-dependent transcriptional activity. Structural analyses of material in active fractions pointed to the saturated diterpenoid phytanic acid, which induced RXR-dependent transcription at concentrations between 4 and 64 microM. Although 200 times more potent than phytanic acid, 9cRA was undetectable in equivalent amounts of extract and cannot be present at a concentration that could account for the activity. Phytanic acid, another phytol metabolite, was synthesized and stimulated RXR with a potency and efficacy similar to phytanic acid. These metabolites specifically displaced [3H]-9cRA from RXR with Ki values of 4 microM, indicating that their transcriptional effects are mediated by direct receptor interactions. Phytol metabolites are compelling candidates for physiological effectors, because their RXR binding affinities and activation potencies match their micromolar circulating concentrations. Given their exclusive dietary origin, these chlorophyll metabolites may represent essential nutrients that coordinate cellular metabolism through RXR-dependent signaling pathways.
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Affiliation(s)
- S Kitareewan
- Orphan Receptor Group, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina 27709, USA
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38
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Parker CE, Papac DI, Tomer KB. Monitoring cleavage of fusion proteins by matrix-assisted laser desorption ionization/mass spectrometry: recombinant HIV-1IIIB p26. Anal Biochem 1996; 239:25-34. [PMID: 8660621 DOI: 10.1006/abio.1996.0286] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Matrix-associated laser desorption ionization/mass spectrometry (MALDI/MS) has been used to examine whole bacteria for the presence of a recombinant HIV p26 fusion protein. MALDI/MS, combined with affinity-purification techniques, is also shown to be very useful in monitoring the enzymatic cleavage of both affinity-bound fusion protein and fusion protein in solution. The combination of mass resolution, sensitivity, and speed of analysis makes MALDI/MS an attractive alternative to SDS-PAGE.
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Affiliation(s)
- C E Parker
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, 27709, USA
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39
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Parker CE, Papac DI, Trojak SK, Tomer KB. Epitope mapping by mass spectrometry: determination of an epitope on HIV-1 IIIB p26 recognized by a monoclonal antibody. The Journal of Immunology 1996. [DOI: 10.4049/jimmunol.157.1.198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Matrix-assisted laser desorption mass spectrometry in combination with proteolytic protection assays has been used to identify the functional epitope on HIV-1 IIIB p26 recognized by a mAb. In this procedure, the intact protein is affinity bound to an immobilized mAb under physiologic conditions. A combination of proteolytic enzymatic cleavages was then performed to remove unprotected residues. Protected residues were identified by matrix-assisted laser desorption mass spectrometry based on their m.w. With this approach, an 11-residue sequence was identified as the most tightly affinity-bound fragment. in addition, two less tightly bound segments were observed. These latter two residues may contain elements of a discontinuous epitope or may be residues involved in a wider contact area. The combination of matrix-assisted laser desorption and proteolytic epitope footprinting has been applied to the determination of the epitope on a recombinant protein recognized by a mAb but should be equally applicable to the definition of an epitope on a native protein in its natural folded conformation.
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Affiliation(s)
- C E Parker
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Science, Research Triangle Park, NC 27709, USA
| | - D I Papac
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Science, Research Triangle Park, NC 27709, USA
| | - S K Trojak
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Science, Research Triangle Park, NC 27709, USA
| | - K B Tomer
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Science, Research Triangle Park, NC 27709, USA
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40
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Parker CE, Papac DI, Trojak SK, Tomer KB. Epitope mapping by mass spectrometry: determination of an epitope on HIV-1 IIIB p26 recognized by a monoclonal antibody. J Immunol 1996; 157:198-206. [PMID: 8683115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Matrix-assisted laser desorption mass spectrometry in combination with proteolytic protection assays has been used to identify the functional epitope on HIV-1 IIIB p26 recognized by a mAb. In this procedure, the intact protein is affinity bound to an immobilized mAb under physiologic conditions. A combination of proteolytic enzymatic cleavages was then performed to remove unprotected residues. Protected residues were identified by matrix-assisted laser desorption mass spectrometry based on their m.w. With this approach, an 11-residue sequence was identified as the most tightly affinity-bound fragment. in addition, two less tightly bound segments were observed. These latter two residues may contain elements of a discontinuous epitope or may be residues involved in a wider contact area. The combination of matrix-assisted laser desorption and proteolytic epitope footprinting has been applied to the determination of the epitope on a recombinant protein recognized by a mAb but should be equally applicable to the definition of an epitope on a native protein in its natural folded conformation.
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Affiliation(s)
- C E Parker
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Science, Research Triangle Park, NC 27709, USA
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41
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Chamulitrat W, Parker CE, Tomer KB, Mason RP. Phenyl N-tert-butyl nitrone forms nitric oxide as a result of its FE(III)-catalyzed hydrolysis or hydroxyl radical adduct formation. Free Radic Res 1995; 23:1-14. [PMID: 7647915 DOI: 10.3109/10715769509064014] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Phenyl N-tert-butyl nitrone (PBN) is commonly employed in spin-trapping studies. We report here evidence that PBN in aqueous solutions is decomposed by two pathways leading to the generation of nitric oxide (.NO). The first pathway is by hydrolysis of PBN, which is strongly catalyzed by ferric iron. The second pathway is via PBN-hydroxyl radical adduct formation. .NO was trapped in the presence of cysteine and ferrous iron to form a [(cys)2Fe(NO)2]-3 complex, which was measured by use of electron paramagnetic resonance (EPR) spectroscopy. A concomitant metabolite, benzaldehyde, was detected from both reaction mixtures. We propose that PBN is hydrolyzed by Fe3+ or attacked by hydroxyl radical, leading eventually to a common transient species, tert-butyl hydronitroxide [t-BuN(O.)H], which is further oxidized to a .NO source, t-BuNO. Our data imply that PBN may decompose to .NO when used in biological models with oxidative stress conditions.
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Affiliation(s)
- W Chamulitrat
- Laboratory of Molecular Biophysics, National Institute of Environmental Health, Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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Niewiesk S, Daenke S, Parker CE, Taylor G, Weber J, Nightingale S, Bangham CR. Naturally occurring variants of human T-cell leukemia virus type I Tax protein impair its recognition by cytotoxic T lymphocytes and the transactivation function of Tax. J Virol 1995; 69:2649-53. [PMID: 7533860 PMCID: PMC188948 DOI: 10.1128/jvi.69.4.2649-2653.1995] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
There is a high degree of intraisolate sequence heterogeneity in the tax gene of human T-cell leukemia virus type I (HTLV-I), although the sequence variation between patients is small compared with that of human immunodeficiency virus type 1. In the present study, we investigated whether naturally occurring amino acid substitutions changed the properties of the Tax protein in two respects: first, recognition of the protein by cytotoxic T lymphocytes (CTL), and second, the ability of the Tax protein to transactivate various promoters. We found that (i) all of the observed amino acid substitutions that occur in known CTL epitopes abolished the recognition of the synthetic peptide representing the respective epitope; (ii) these substitutions occurred significantly more frequently in subjects carrying HLA-A2; and (iii) most of the amino acid substitutions severely reduced the ability of Tax protein to transactivate three promoters: the HTLV-I long terminal repeat, the c-fos promoter, and the interleukin-2 receptor alpha chain promoter.
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Affiliation(s)
- S Niewiesk
- Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
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Bangham CRM, Daenke S, Niewiesk S, Parker CE, Taylor G, Weber J, Nightingale S. T-cells select defective variants of HTLV-I. J Cancer Res Clin Oncol 1995. [DOI: 10.1007/bf02559870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Niewiesk S, Daenke S, Parker CE, Taylor G, Weber J, Nightingale S, Bangham CR. The transactivator gene of human T-cell leukemia virus type I is more variable within and between healthy carriers than patients with tropical spastic paraparesis. J Virol 1994; 68:6778-81. [PMID: 8084014 PMCID: PMC237103 DOI: 10.1128/jvi.68.10.6778-6781.1994] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Human T-cell leukemia virus type I (HTLV-1) causes T-cell leukemia and tropical spastic paraparesis (TSP) in a minority of infected people, whereas the majority remain healthy. No association between a particular HTLV-I sequence and disease manifestation has been found in previous studies. We studied here the sequence variability of the gene for the HTLV-I Tax protein, which is the dominant target antigen of the very strong cytotoxic T-lymphocyte response to the virus. In HTLV-I infection, the intraisolate nucleotide variability is much greater than the variability between isolates. The predicted protein sequence of Tax was significantly more variable in the healthy seropositive individuals' provirus than in those of the patients with TSP. Thus, tax sequence heterogeneity, rather than the presence of particular sequences, distinguishes healthy HTLV-I-seropositive individuals from patients with TSP.
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Affiliation(s)
- S Niewiesk
- Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
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Parker CE, Nightingale S, Taylor GP, Weber J, Bangham CR. Circulating anti-Tax cytotoxic T lymphocytes from human T-cell leukemia virus type I-infected people, with and without tropical spastic paraparesis, recognize multiple epitopes simultaneously. J Virol 1994; 68:2860-8. [PMID: 7512153 PMCID: PMC236774 DOI: 10.1128/jvi.68.5.2860-2868.1994] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
CD8+ T cells were freshly isolated from a human T-cell leukemia virus type I (HTLV-I)-infected patient with tropical spastic paraparesis. These cells, which were specific for HTLV-I Tax, simultaneously recognized a minimum of five, and possibly as many as seven, distinct peptide epitopes within the protein. A further Tax epitope was recognized after a short period of culture without exogenous peptide stimulation. All but one of these epitopes were clustered in the N-terminal third of Tax, and one of the epitopes was clearly immunodominant on two separate occasions of testing. Recognition of the immunodominant epitope was restricted by human leukocyte antigen (HLA) B15, and recognition of all the others was by HLA A2. Similar patterns of cytotoxic T lymphocyte recognition of the HLA A2-restricted Tax peptides in two healthy HTLV-I-seropositive individuals, each of whom carried the HLA A2 allele, were observed.
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Affiliation(s)
- C E Parker
- Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, United Kingdom
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46
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Daenke S, Parker CE, Niewiesk S, Newsom-Davis J, Nightingale S, Bangham CR. Spastic paraparesis in a patient carrying defective human T cell leukemia virus type I (HTLV-I) provirus sequences but lacking a humoral or cytotoxic T cell response to HTLV-I. J Infect Dis 1994; 169:941-3. [PMID: 8133118 DOI: 10.1093/infdis/169.4.941] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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47
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Weinmann W, Maier C, Baumeister K, Przybylski M, Parker CE, Tomer KB. Isolation of hydrophobic lipoproteins in organic solvents by pressure-assisted capillary electrophoresis for subsequent mass spectrometric characterization. J Chromatogr A 1994; 664:271-5. [PMID: 8199708 DOI: 10.1016/0021-9673(94)87015-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Two capillary electrophoretic (CE) separation techniques with either simultaneous solvent flow induced by hydrostatic pressure or CE followed by low pressurization with helium were developed for the analysis of extremely hydrophobic proteins, such as the lung surfactant protein SP-C. For both related procedures, buffer solutions containing up to 70% of 2-propanol were used for the capillary electrophoretic separation. This high concentration of organic co-solvent, needed to solubilize the protein, dramatically reduces the electroosmotic flow (EOF) in aminopropyltrimethoxysilane-treated fused-silica capillaries. Because the EOF was insufficient to elute the separated analytes from the capillary, two "pressure-assisted" CE techniques were developed. An additional flow to elute the separated analytes was produced either by raising the inlet of the capillary or by helium pressure. Using the pressurization procedure a baseline separation of the SP-C protein and its dimeric complex was obtained in a 55-minute electrophoretic run, followed by pressure elution of the analyte to the detector. The present combination of pressurization and capillary electrophoresis does not require any detergents or involatile buffer additives, which are usually needed to solubilize extremely hydrophobic lipoproteins. It is therefore applicable to on-line coupling with electrospray mass spectrometry for the direct structural characterization of hydrophobic proteins.
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Affiliation(s)
- W Weinmann
- Fakultät für Chemie, Universität Konstanz, Germany
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48
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Iwasaki M, Darden TA, Parker CE, Tomer KB, Pedersen LG, Negishi M. Inherent versatility of P-450 oxygenase. Conferring dehydroepiandrosterone hydroxylase activity to P-450 2a-4 by a single amino acid mutation at position 117. J Biol Chem 1994; 269:9079-83. [PMID: 8132645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Mouse steroid 15 alpha-hydroxylase P-450 2a-4 is restricted in its substrate specificity to the delta 4, 3-ketone steroids such as androstenedione. As a result, the P-450 exhibits little hydroxylase activity toward delta 5, 3-hydroxysteroids including dehydroepiandrosterone (DHEA). A single amino acid mutation of Ala at position 117 to Val, however, is enough to confer a high DHEA hydroxylase activity to P-450 2a-4 with 7 alpha-OH DHEA as one of the two major hydroxylated metabolites. Mouse coumarin 7-hydroxylase P-450 2a-5 contains Val at position 117, but it exhibits very low DHEA hydroxylase activity. P-450 2a-5 acquires high DHEA hydroxylase activity, however, by a mutation of Phe-209 to Asn. Moreover, the mutant P-450 2a-5 loses its activity when Val is replaced by Ala at position 117. The residue at position 117, therefore, plays the principal role in the determination of the DHEA hydroxylase activity of the P-450s. Conversely, mutations at residue 117 have little effect on the androstenedione hydroxylase activities of the P-450s. Further modeling of the DHEA binding orientation in the substrate-heme pocket of bacterial P-450cam (Iwasaki, M., Darden, T., Pedersen, L., Davis, D. G., Juvonen, R. O., Sueyoshi, T., and Negishi, M. (1993) J. Biol. Chem. 268, 759-762) provides support for the hypothesis that the type of residue at position 117 determines the steroid-substrate specificity of the P-450 depending on the substituent at the C3 position of steroid molecule.
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Affiliation(s)
- M Iwasaki
- National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709
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Weinmann W, Parker CE, Baumeister K, Maier C, Tomer KB, Przybylski M. Capillary electrophoresis combined with 252Cf plasma desorption and electrospray mass spectrometry for the structural characterization of hydrophobic polypeptides using organic solvents. Electrophoresis 1994; 15:228-33. [PMID: 8026439 DOI: 10.1002/elps.1150150139] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Capillary electrophoresis (CE) conditions have been developed for the separation of hydrophobic polypeptides, such as fatty acid-acylated peptides, and their subsequent structural identification by 252Cf plasma desorption (PDMS) and electrospray mass spectrometry (ESMS). Salt- and detergent-free aqueous acetic acid buffers containing up to 20% 2-propanol or 25% acetonitrile were employed for CE separations of hydrophobic peptides with (i) untreated, and (ii) 3-aminopropyltrimethoxysilane-derived fused silica capillaries. For both capillary types, electroosmotic flow rates suitable for sample isolation and transfer were determined, and CE separations of polypeptide mixtures were compared for aqueous buffers containing 2-propanol or acetonitrile. For the mass spectrometric identification of CE-separated peptides, a sheath flow sample isolation method was developed for subsequent transfer to PDMS. This procedure enabled the efficient isolation of peptide fractions for PDMS analysis, or alternative microanalytical techniques.
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Affiliation(s)
- W Weinmann
- Fakultät für Chemie, Universität Konstanz, Germany
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Parker CE, Perkins JR, Tomer KB, Shida Y, O'Hara K. Nanoscale packed capillary liquid chromatography-electrospray ionization mass spectrometry: analysis of penicillins and cephems. J Chromatogr 1993; 616:45-57. [PMID: 8376492 DOI: 10.1016/0378-4347(93)80470-o] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A series of seventeen penicillins and cephems (cephalosporins and cephamycins) was examined by electrospray ionization. Separations by nanoscale packed-capillary liquid chromatography, with sub-microliter flow-rates, were performed using methanol-water and acetonitrile-water both containing trifluoroacetic acid gradients. In the on-column analyses, the protonated species usually predominate, and the fragment ions are often present which can be used for confirmation of compound identity. With combined nanoscale packed-capillary liquid chromatography-electrospray ionization mass spectrometry, separations and full-scan mass spectra can be obtained on *q12-15 ng of analyte, allowing the analysis of therapeutic levels of these antibiotics from only a few microliters of serum.
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Affiliation(s)
- C E Parker
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
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