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Evrard YA, Newton D, Das B, Alcoser SY, Arthur K, Baldwin M, Bonomi C, Borgel S, Carter J, Chase T, Chen A, Chen L, Craig NE, Datta V, Delaney E, Divelbiss R, Dougherty K, Forbes T, Georgius K, Geraghty J, Gibson M, Gottholm-Ahalt MM, Grinnage-Pulley T, Hedger K, Hoffman S, Karlovich C, Lassoued W, Jiwani S, Mallow C, McGlynn C, Morris M, Moyer J, Mullendore M, Murphy M, Patidar R, Plater K, Radzyminski M, Scott N, Stockwin LH, Stotler H, Stottlemyer J, Styers S, Trail D, Vilimas T, Wade A, Walke A, Walsh T, Williams PM, Hollingshead MG, Doroshow JH. Abstract 4524: Comparison of PDX, PDC, and PDOrg models from the National Cancer Institute’s Patient-Derived Models Repository (PDMR). Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-4524] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The National Cancer Institute (NCI) has developed a Patient-Derived Models Repository (PDMR) comprised of quality-controlled, early-passage, clinically-annotated patient-derived tumor xenografts (PDXs), in vitro tumor cell cultures (PDCs), cancer associated fibroblasts (CAFs), and patient-derived organoids (PDOrg). NCI has focused on generating models to complement existing PDX collections and address unmet needs in the preclinical model space. These models are offered to the extramural community for research use (https://pdmr.cancer.gov), along with clinical annotation and molecular information (whole exome sequence, gene expression using RNASeq), via a publicly accessible database. Currently, over 200 PDX models, 50 PDC models, and 100 CAF models are available for distribution to the US research community. Approximately 50 PDOrg models will be released in early 2019. As part of its rare cancer initiative, the NCI is also targeting the collection of infrequently-observed tumor histologies to advance both biological investigations and drug development efforts for under-studied malignancies. Comparison of matched models, models where more than one model type are available (e.g., PDX and PDC), demonstrate a high degree of concordance across the model types. Genetic stability across the models is assessed using multiple criteria including genetic assessment of CNVs and presence of driver mutations. Optimal CNV assessment uses whole exome sequence data corrected for cellularity in the patient specimen using germline reads and corrected for cellularity in the PDX specimens by subtraction of the mouse reads. Histomorphologic comparison of PDXs and cell line xenografts (CLX) generated from in vitro PDCs and PDOrgs also overall show a high degree of concordance, though loss of features and dedifferentiation can be observed in some models. Overall these models demonstrate a high degree of conservation at the genetic and pathologic level when compared to the patient tumor. These models can provide researchers the ability to perform high- or mid-throughput screening in 2D or 3D culture followed by targeted selection of PDX models for in vivo studies. Funded by NCI Contract No. HHSN261200800001E
Citation Format: Yvonne A. Evrard, Dianne Newton, Biswajit Das, Sergio Y. Alcoser, Kaitlyn Arthur, Mariah Baldwin, Carrie Bonomi, Suzanne Borgel, John Carter, Tiffany Chase, Alice Chen, Lily Chen, Nikki E. Craig, Vivekananda Datta, Emily Delaney, Raymond Divelbiss, Kelly Dougherty, Thomas Forbes, Kyle Georgius, Joe Geraghty, Marion Gibson, Michelle M. Gottholm-Ahalt, Tara Grinnage-Pulley, Kelly Hedger, Sierra Hoffman, Chris Karlovich, Wiem Lassoued, Shahanawaz Jiwani, Candace Mallow, Chelsea McGlynn, Mallorie Morris, Jenna Moyer, Mike Mullendore, Matt Murphy, Rajesh Patidar, Kevin Plater, Marianne Radzyminski, Nicki Scott, Luke H. Stockwin, Howard Stotler, Jesse Stottlemyer, Savanna Styers, Debbie Trail, Tomas Vilimas, Anna Wade, Abigail Walke, Thomas Walsh, P. Mickey Williams, Melinda G. Hollingshead, James H. Doroshow. Comparison of PDX, PDC, and PDOrg models from the National Cancer Institute’s Patient-Derived Models Repository (PDMR) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4524.
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Affiliation(s)
- Yvonne A. Evrard
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Dianne Newton
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Biswajit Das
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | - Kaitlyn Arthur
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Mariah Baldwin
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Carrie Bonomi
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Suzanne Borgel
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - John Carter
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Tiffany Chase
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Alice Chen
- 2National Cancer Institute, Frederick, MD
| | - Lily Chen
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Nikki E. Craig
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | - Emily Delaney
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | - Kelly Dougherty
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Thomas Forbes
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Kyle Georgius
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Joe Geraghty
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Marion Gibson
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | | | - Kelly Hedger
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Sierra Hoffman
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Chris Karlovich
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Wiem Lassoued
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | - Candace Mallow
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Chelsea McGlynn
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Mallorie Morris
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Jenna Moyer
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Mike Mullendore
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Matt Murphy
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Rajesh Patidar
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Kevin Plater
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | - Nicki Scott
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Luke H. Stockwin
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Howard Stotler
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | - Savanna Styers
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Debbie Trail
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Tomas Vilimas
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Anna Wade
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Abigail Walke
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Thomas Walsh
- 1Frederick National Laboratory for Cancer Research, Frederick, MD
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2
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Iacocca E, Liu TM, Reid AH, Fu Z, Ruta S, Granitzka PW, Jal E, Bonetti S, Gray AX, Graves CE, Kukreja R, Chen Z, Higley DJ, Chase T, Le Guyader L, Hirsch K, Ohldag H, Schlotter WF, Dakovski GL, Coslovich G, Hoffmann MC, Carron S, Tsukamoto A, Kirilyuk A, Kimel AV, Rasing T, Stöhr J, Evans RFL, Ostler T, Chantrell RW, Hoefer MA, Silva TJ, Dürr HA. Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys. Nat Commun 2019; 10:1756. [PMID: 30988403 PMCID: PMC6465265 DOI: 10.1038/s41467-019-09577-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 03/13/2019] [Indexed: 11/09/2022] Open
Abstract
Sub-picosecond magnetisation manipulation via femtosecond optical pumping has attracted wide attention ever since its original discovery in 1996. However, the spatial evolution of the magnetisation is not yet well understood, in part due to the difficulty in experimentally probing such rapid dynamics. Here, we find evidence of a universal rapid magnetic order recovery in ferrimagnets with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify magnon localisation and coalescence processes, whereby localised magnetic textures nucleate and subsequently interact and grow in accordance with a power law formalism. A hydrodynamic representation of the numerical simulations indicates that the appearance of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 107 A cm-2. Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. The magnon processes discussed here provide new insights for the stabilization of desired meta-stable states.
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Affiliation(s)
- E Iacocca
- Department of Applied Mathematics, University of Colorado, Boulder, CO, 80309, USA
- National Institute of Standards and Technology, Boulder, CO, 80305, USA
- Department of Physics, Division for Theoretical Physics, Chalmers University of Technology, Gothenburg, 412 96, Sweden
| | - T-M Liu
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - A H Reid
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Z Fu
- School of Physics, Science, and Engineering, Tongji University, Shanghai, 200092, China
| | - S Ruta
- Department of Physics, University of York, York, YO10 5DD, UK
| | - P W Granitzka
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - E Jal
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - S Bonetti
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
- Department of Physics, Stockholm University, Stockholm, 106 91, Sweden
- Department of Molecular Science and Nanosystems, Ca' Foscari University of Venice, Venezia-Mestre, 30172, Italy
| | - A X Gray
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
- Department of Physics, Temple University, 1925 N. 12th St., Philadelphia, PA, 19122, USA
| | - C E Graves
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - R Kukreja
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Z Chen
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - D J Higley
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - T Chase
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - L Le Guyader
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
- Spectroscopy & Coherent Scattering, European X-Ray Free-Electron Laser Facility GmbH, Holzkoppel 4, 22869, Schenefeld, Germany
| | - K Hirsch
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - H Ohldag
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - W F Schlotter
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - G L Dakovski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - G Coslovich
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - M C Hoffmann
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - S Carron
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - A Tsukamoto
- Department of Electronics and Computer Science, Nihon University, 7-24-1 Narashino-dai Funabashi, Chiba, 274-8501, Japan
| | - A Kirilyuk
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - A V Kimel
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Th Rasing
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - J Stöhr
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - R F L Evans
- Department of Physics, University of York, York, YO10 5DD, UK
| | - T Ostler
- Physique des Matériaux et Nanostructures, Université de Liège, Liège, B-4000, Sart Tilman, Belgium
- Faculty of Arts, Computing, Engineering and Sciences, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | - R W Chantrell
- Department of Physics, University of York, York, YO10 5DD, UK
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - M A Hoefer
- Department of Applied Mathematics, University of Colorado, Boulder, CO, 80309, USA
| | - T J Silva
- National Institute of Standards and Technology, Boulder, CO, 80305, USA
| | - H A Dürr
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
- Department of Physics and Astronomy, Uppsala University, Box 516, 751 20, Uppsala, Sweden.
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3
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Chen Z, Higley DJ, Beye M, Hantschmann M, Mehta V, Hellwig O, Mitra A, Bonetti S, Bucher M, Carron S, Chase T, Jal E, Kukreja R, Liu T, Reid AH, Dakovski GL, Föhlisch A, Schlotter WF, Dürr HA, Stöhr J. Ultrafast Self-Induced X-Ray Transparency and Loss of Magnetic Diffraction. Phys Rev Lett 2018; 121:137403. [PMID: 30312105 DOI: 10.1103/physrevlett.121.137403] [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: 05/17/2018] [Indexed: 06/08/2023]
Abstract
Using ultrafast ≃2.5 fs and ≃25 fs self-amplified spontaneous emission pulses of increasing intensity and a novel experimental scheme, we report the concurrent increase of stimulated emission in the forward direction and loss of out-of-beam diffraction contrast for a Co/Pd multilayer sample. The experimental results are quantitatively accounted for by a statistical description of the pulses in conjunction with the optical Bloch equations. The dependence of the stimulated sample response on the incident intensity, coherence time, and energy jitter of the employed pulses reveals the importance of increased control of x-ray free electron laser radiation.
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Affiliation(s)
- Z Chen
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - D J Higley
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - M Beye
- Department of Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany
| | - M Hantschmann
- Department of Materials and Energy Science, Helmholtz Zentrum Berlin, D-14109 Berlin, Germany
| | - V Mehta
- San Jose Research Center, HGST a Western Digital company, San Jose, California 95135, USA
| | - O Hellwig
- Institute of Physics, Technische Universität Chemnitz, D-09107 Chemnitz, Germany
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - A Mitra
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, University of Warwick, CV4 7AL Coventry, United Kingdom
| | - S Bonetti
- Department of Physics, Stockholm University, S-10691 Stockholm, Sweden
| | - M Bucher
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - S Carron
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - T Chase
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - E Jal
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R Kukreja
- Department of Materials Science and Engineering, University of California Davis, Davis, California 95616, USA
| | - T Liu
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - A H Reid
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - G L Dakovski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - A Föhlisch
- Department of Materials and Energy Science, Helmholtz Zentrum Berlin, D-14109 Berlin, Germany
| | - W F Schlotter
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - H A Dürr
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
| | - J Stöhr
- SLAC National Accelerator Laboratory and Department of Photon Science, Stanford, California 94035, USA
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4
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Reid AH, Shen X, Maldonado P, Chase T, Jal E, Granitzka PW, Carva K, Li RK, Li J, Wu L, Vecchione T, Liu T, Chen Z, Higley DJ, Hartmann N, Coffee R, Wu J, Dakovski GL, Schlotter WF, Ohldag H, Takahashi YK, Mehta V, Hellwig O, Fry A, Zhu Y, Cao J, Fullerton EE, Stöhr J, Oppeneer PM, Wang XJ, Dürr HA. Beyond a phenomenological description of magnetostriction. Nat Commun 2018; 9:388. [PMID: 29374151 PMCID: PMC5786062 DOI: 10.1038/s41467-017-02730-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [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: 12/02/2016] [Accepted: 12/19/2017] [Indexed: 11/10/2022] Open
Abstract
Magnetostriction, the strain induced by a change in magnetization, is a universal effect in magnetic materials. Owing to the difficulty in unraveling its microscopic origin, it has been largely treated phenomenologically. Here, we show how the source of magnetostriction-the underlying magnetoelastic stress-can be separated in the time domain, opening the door for an atomistic understanding. X-ray and electron diffraction are used to separate the sub-picosecond spin and lattice responses of FePt nanoparticles. Following excitation with a 50-fs laser pulse, time-resolved X-ray diffraction demonstrates that magnetic order is lost within the nanoparticles with a time constant of 146 fs. Ultrafast electron diffraction reveals that this demagnetization is followed by an anisotropic, three-dimensional lattice motion. Analysis of the size, speed, and symmetry of the lattice motion, together with ab initio calculations accounting for the stresses due to electrons and phonons, allow us to reveal the magnetoelastic stress generated by demagnetization.
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Affiliation(s)
- A H Reid
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA. .,Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
| | - X Shen
- Accelerator Division, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - P Maldonado
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-75120, Uppsala, Sweden
| | - T Chase
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - E Jal
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,CNRS, Laboratoire de Chimie Physique - Matière et Rayonnement, Sorbonne Universités, UPMC Univ. Paris 06, 75005, Paris, France
| | - P W Granitzka
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Van der Waals-Zeeman Institute, University of Amsterdam, 1018XE, Amsterdam, The Netherlands
| | - K Carva
- Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, CZ-12116, Prague 2, Czech Republic
| | - R K Li
- Accelerator Division, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - J Li
- Brookhaven National Laboratory, Upton, NY, 1193, USA
| | - L Wu
- Brookhaven National Laboratory, Upton, NY, 1193, USA
| | - T Vecchione
- Accelerator Division, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - T Liu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Department of Physics, Stanford University, Stanford, CA, 94305, USA
| | - Z Chen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Department of Physics, Stanford University, Stanford, CA, 94305, USA
| | - D J Higley
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.,Department of Applied Physics, Stanford University, Stanford, CA, 94305, USA
| | - N Hartmann
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - R Coffee
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - J Wu
- Accelerator Division, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - G L Dakovski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - W F Schlotter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - H Ohldag
- Stanford Synchrotron Radiation Laboratory, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Y K Takahashi
- Magnetic Materials Unit, National Institute for Materials Science, Tsukuba, 305-0047, Japan
| | - V Mehta
- San Jose Research Center, HGST a Western Digital Company, 3403 Yerba Buena Road, San Jose, CA, 95135, USA.,Thomas J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, NY, 10598, USA
| | - O Hellwig
- San Jose Research Center, HGST a Western Digital Company, 3403 Yerba Buena Road, San Jose, CA, 95135, USA.,Institute of Physics, Technische Universität Chemnitz, Reichenhainer Straße 70, D-09107, Chemnitz, Germany.,Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01328, Dresden, Germany
| | - A Fry
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - Y Zhu
- Brookhaven National Laboratory, Upton, NY, 1193, USA
| | - J Cao
- Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA
| | - E E Fullerton
- Center for Memory and Recording Research, UC San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0401, USA
| | - J Stöhr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - P M Oppeneer
- Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-75120, Uppsala, Sweden
| | - X J Wang
- Accelerator Division, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - H A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA. .,Department of Physics and Astronomy, Uppsala University, P. O. Box 516, S-75120, Uppsala, Sweden.
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5
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Sokolowski-Tinten K, Shen X, Zheng Q, Chase T, Coffee R, Jerman M, Li RK, Ligges M, Makasyuk I, Mo M, Reid AH, Rethfeld B, Vecchione T, Weathersby SP, Dürr HA, Wang XJ. Electron-lattice energy relaxation in laser-excited thin-film Au-insulator heterostructures studied by ultrafast MeV electron diffraction. Struct Dyn 2017; 4:054501. [PMID: 28795080 PMCID: PMC5522339 DOI: 10.1063/1.4995258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 07/10/2017] [Indexed: 05/19/2023]
Abstract
We apply time-resolved MeV electron diffraction to study the electron-lattice energy relaxation in thin film Au-insulator heterostructures. Through precise measurements of the transient Debye-Waller-factor, the mean-square atomic displacement is directly determined, which allows to quantitatively follow the temporal evolution of the lattice temperature after short pulse laser excitation. Data obtained over an extended range of laser fluences reveal an increased relaxation rate when the film thickness is reduced or the Au-film is capped with an additional insulator top-layer. This behavior is attributed to a cross-interfacial coupling of excited electrons in the Au film to phonons in the adjacent insulator layer(s). Analysis of the data using the two-temperature-model taking explicitly into account the additional energy loss at the interface(s) allows to deduce the relative strength of the two relaxation channels.
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Affiliation(s)
- K Sokolowski-Tinten
- Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - X Shen
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - Q Zheng
- School of Materials and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, China
| | - T Chase
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - R Coffee
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - M Jerman
- Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - R K Li
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - M Ligges
- Faculty of Physics and Centre for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - I Makasyuk
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - M Mo
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - A H Reid
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - B Rethfeld
- Department of Physics and OPTIMAS Research Center, Technical University Kaiserslautern, Erwin-Schrödinger-Strae 46, 67663 Kaiserslautern, Germany
| | - T Vecchione
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - S P Weathersby
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - H A Dürr
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
| | - X J Wang
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, California 94025, USA
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6
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Le Guyader L, Chase T, Reid AH, Li RK, Svetin D, Shen X, Vecchione T, Wang XJ, Mihailovic D, Dürr HA. Stacking order dynamics in the quasi-two-dimensional dichalcogenide 1 T-TaS 2 probed with MeV ultrafast electron diffraction. Struct Dyn 2017; 4:044020. [PMID: 28503631 PMCID: PMC5415401 DOI: 10.1063/1.4982918] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/21/2017] [Indexed: 05/29/2023]
Abstract
Transitions between different charge density wave (CDW) states in quasi-two-dimensional materials may be accompanied also by changes in the inter-layer stacking of the CDW. Using MeV ultrafast electron diffraction, the out-of-plane stacking order dynamics in the quasi-two-dimensional dichalcogenide 1T-TaS2 is investigated for the first time. From the intensity of the CDW satellites aligned around the commensurate l = 1/6 characteristic stacking order, it is found out that this phase disappears with a 0.3 ps time constant. Simultaneously, in the same experiment, the emergence of the incommensurate phase, with a slightly slower 2.0 ps time constant, is determined from the intensity of the CDW satellites aligned around the incommensurate l = 1/3 characteristic stacking order. These results might be of relevance in understanding the metallic character of the laser-induced metastable "hidden" state recently discovered in this compound.
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Affiliation(s)
| | | | - A H Reid
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R K Li
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - D Svetin
- Jozef Stefan Institute and CENN Nanocenter, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - X Shen
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - T Vecchione
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - X J Wang
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - D Mihailovic
- Jozef Stefan Institute and CENN Nanocenter, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - H A Dürr
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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7
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Chase T, Robillard R, Courtney D, Armitage R, Ward M, De Koninck J, Lee EK. 0859 ADOLESCENTS WITH TREATMENT RESISTANT DEPRESSION: COULD SLEEP DISORDERED BREATHING BE INVOLVED? Sleep 2017. [DOI: 10.1093/sleepj/zsx050.858] [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: 11/13/2022] Open
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8
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Gray AX, Jeong J, Aetukuri NP, Granitzka P, Chen Z, Kukreja R, Higley D, Chase T, Reid AH, Ohldag H, Marcus MA, Scholl A, Young AT, Doran A, Jenkins CA, Shafer P, Arenholz E, Samant MG, Parkin SSP, Dürr HA. Correlation-Driven Insulator-Metal Transition in Near-Ideal Vanadium Dioxide Films. Phys Rev Lett 2016; 116:116403. [PMID: 27035314 DOI: 10.1103/physrevlett.116.116403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Indexed: 06/05/2023]
Abstract
We use polarization- and temperature-dependent x-ray absorption spectroscopy, in combination with photoelectron microscopy, x-ray diffraction, and electronic transport measurements, to study the driving force behind the insulator-metal transition in VO_{2}. We show that both the collapse of the insulating gap and the concomitant change in crystal symmetry in homogeneously strained single-crystalline VO_{2} films are preceded by the purely electronic softening of Coulomb correlations within V-V singlet dimers. This process starts 7 K (±0.3 K) below the transition temperature, as conventionally defined by electronic transport and x-ray diffraction measurements, and sets the energy scale for driving the near-room-temperature insulator-metal transition in this technologically promising material.
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Affiliation(s)
- A X Gray
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Temple University, 1925 North 12th Street, Philadelphia, Pennsylvania 19130, USA
| | - J Jeong
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - N P Aetukuri
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - P Granitzka
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Van der Waals-Zeeman Institute, University of Amsterdam, 1018XE Amsterdam, The Netherlands
| | - Z Chen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Physics, Stanford University, Stanford, California 94305, USA
| | - R Kukreja
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - D Higley
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - T Chase
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - A H Reid
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - H Ohldag
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M A Marcus
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - A Scholl
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - A T Young
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - A Doran
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - C A Jenkins
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - P Shafer
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - E Arenholz
- Advanced Light Source, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, California 94720, USA
| | - M G Samant
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - S S P Parkin
- IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120, USA
| | - H A Dürr
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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Abstract
Radiocarbon incorporation from pyruvate and serine into monomethylmercury by Desulfovibrio desulfuricans was consistent with the proposal that the methyl group originates from C-3 of serine. Immunodiagnostic assays measured 4 to 35 mug of tetrahydrofolate and 58 to 161 ng of cobalamin or a closely related cobalt porphyrin per g of cell protein in D. desulfuricans. The light-reversible inhibition of mercury methylation by propyl iodide in D. desulfuricans indicates methyl transfer by a cobalt porphyrin.
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Affiliation(s)
- M Berman
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08903
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Abstract
A number of species of nematode-trapping fungi, which capture and digest nematodes having keratin and collagen in their cuticles, were tested for the ability to produce extracellular collagenase and keratinase. Collagenase, which is active on ichthyocol, earthworm collagen, and procollagen from chicken embryo fibroblasts, was found in the growth medium of all tested species; keratinase was not found. The enzyme from Arthrobotrys amerospora was concentrated by precipitation with (NH(4))(2)SO(4) and further purified by adsorption on collagen at 0 degrees C. The collagenase was active over a pH range of 2.5 to 10.0. It was not inactivated by dialysis against ethylenediaminetetraacetic acid for 48 h or by the sulfhydryl group inhibitors N-ethylmaleimide and p-chloromercuribenzoate. The production of collagenase may aid the fungus to penetrate the cuticle of its prey.
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Affiliation(s)
- S Schenck
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08903
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Pearson T, Shultz LD, Lief J, Burzenski L, Gott B, Chase T, Foreman O, Rossini AA, Bottino R, Trucco M, Greiner DL. A new immunodeficient hyperglycaemic mouse model based on the Ins2Akita mutation for analyses of human islet and beta stem and progenitor cell function. Diabetologia 2008; 51:1449-56. [PMID: 18563383 PMCID: PMC2719841 DOI: 10.1007/s00125-008-1057-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 04/24/2008] [Indexed: 11/25/2022]
Abstract
AIMS/HYPOTHESIS To develop and validate a new immunodeficient mouse strain that spontaneously develops a non-autoimmune hyperglycaemia to serve as a diabetic host for human islets and human beta stem and progenitor cells without the need for induction of hyperglycaemia by toxic chemicals with their associated side effects. METHODS We generated and characterised a new strain of immunodeficient spontaneously hyperglycaemic mice, the NOD-Rag1null Prf1null Ins2Akita strain and compared this strain with the NOD-scid Il2rgammanull (also known as Il2rg) immunodeficient strain rendered hyperglycaemic by administration of a single dose of streptozotocin. Hyperglycaemic mice were transplanted with human islets ranging from 1,000 to 4,000 islet equivalents (IEQ) and were monitored for normalisation of blood glucose levels. RESULTS NOD-Rag1null Prf1null Ins2Akita mice developed spontaneous hyperglycaemia, similar to Ins2Akita-harbouring strains of immunocompetent mice. Histological examination of islets in the host pancreas validated the spontaneous loss of beta cell mass in the absence of mononuclear cell infiltration. Human islets transplanted into spontaneously diabetic NOD-Rag1null Prf1null Ins2Akita and chemically diabetic NOD-scid Il2rgammanull mice resulted in a return to euglycaemia that occurred with transplantation of similar beta cell masses. CONCLUSIONS/INTERPRETATION The NOD-Rag1null Prf1null Ins2Akita mouse is the first immunodeficient, spontaneously hyperglycaemic mouse strain described that is based on the Ins2Akita mutation. This strain is suitable as hosts for human islet and human beta stem and progenitor cell transplantation in the absence of the need for pharmacological induction of diabetes. This strain of mice also has low levels of innate immunity and can be engrafted with a human immune system for the study of human islet allograft rejection.
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Affiliation(s)
- T. Pearson
- Diabetes Division, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | | | - J. Lief
- Diabetes Division, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | | | - B. Gott
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - T. Chase
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - O. Foreman
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - A. A. Rossini
- Diabetes Division, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - R. Bottino
- Division of Immunogenetics, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, USA
| | - M. Trucco
- Division of Immunogenetics, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, USA
| | - D. L. Greiner
- Diabetes Division, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Chase T, Carrey N, Soo E, Wilkinson M. Methylphenidate regulates activity regulated cytoskeletal associated but not brain-derived neurotrophic factor gene expression in the developing rat striatum. Neuroscience 2006; 144:969-84. [PMID: 17156936 DOI: 10.1016/j.neuroscience.2006.10.035] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2006] [Revised: 09/28/2006] [Accepted: 10/26/2006] [Indexed: 12/20/2022]
Abstract
Methylphenidate (MPH) is a psychostimulant drug used to treat attention deficit hyperactivity disorder in children. To explore the central effects of chronic MPH, we investigated the expression of an effector immediate early gene, activity regulated cytoskeletal associated (arc), and the neurotrophin, brain-derived neurotrophic factor (bdnf) in the brain of immature and adult rats following repeated MPH. Prepubertal (postnatal day (PD) 25-38) and adult (PD 53-66) male rats were injected once daily for: a) 14 days with saline or MPH (2 or 10 mg/kg; s.c.) or b) 13 days with saline followed by a single dose of MPH (2 or 10 mg/kg; s.c.). To determine possible long-term effects of MPH, prepubertal rats were allowed a drug-free period of 4 weeks following the 14 days of treatment, and then were given a challenge dose of MPH. We demonstrated, for the first time, that an acute injection of MPH increased levels of activity-regulated cytoskeletal protein (ARC) and arc mRNA in the prepubertal rat striatum and cingulate/frontal cortex. This response was significantly attenuated by chronic MPH. The desensitization in arc expression observed in prepubertal rats persisted in the adult striatum following a later MPH challenge. In contrast to these data we observed little effect of MPH on bdnf expression. We also developed an effective, non-stressful technique to treat freely moving immature rats with oral MPH. Consistent with the results described above, we observed that oral MPH (7.5 and 10 mg/kg) also increased arc expression in the prepubertal rat striatum. However, unlike the effects of injected MPH, repeated oral MPH (7.5 mg/kg) did not alter the normal arc response. This result raises the important possibility that oral doses of MPH that reproduce clinically relevant blood levels of MPH may not down-regulate gene expression, at least in the short term (14 days). We confirmed, using mass spectrometry, that the oral doses of MPH used in our experiments yielded blood levels within the clinical range observed in children. The novel oral administration paradigm that we describe thus provides a clinically relevant animal model to further explore the effects of chronic drug exposure on central gene expression in the developing rat brain.
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Affiliation(s)
- T Chase
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, College Street, Halifax, Nova Scotia, Canada B3H 1X5
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13
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Affiliation(s)
- T Chase
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA
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14
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Esser MJ, Chase T, Allen GV, Sawynok J. Chronic administration of amitriptyline and caffeine in a rat model of neuropathic pain: multiple interactions. Eur J Pharmacol 2001; 430:211-8. [PMID: 11711033 DOI: 10.1016/s0014-2999(01)01276-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [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: 11/15/2022]
Abstract
This study was designed to determine (1) whether chronic amitriptyline administration was effective in alleviating symptoms of neuropathic pain in a rat model of spinal nerve injury, and (2) whether the effect of amitriptyline involved manipulation of endogenous adenosine, by determining the effect of caffeine, a non-selective adenosine A(1) and A(2) receptor antagonist, on its actions. Nerve injury was produced by unilateral spinal nerve ligation of the fifth and sixth lumbar nerves distal to the dorsal root ganglion, and this resulted in stimulus-evoked thermal hyperalgesia and static tactile mechanical allodynia. Animals received pre- and post-surgical intraperitoneal doses of amitriptyline (10 mg/kg) and caffeine (7.5 mg/kg), alone or in combination, and following surgery, were administered amitriptyline (15-18 mg/kg/day) and caffeine (6-8 mg/kg/day), alone or in combination, in the drinking water. Rats were tested for thermal reaction latencies and static tactile thresholds at 7, 14 and 21 days following surgery. In the paw ipsilateral to the nerve ligation, chronic amitriptyline administration consistently decreased the thermal hyperalgesia produced by spinal nerve ligation over a 3-week period, and this effect was blocked by concomitant caffeine administration at all time intervals. In the contralateral paw, thermal withdrawal latencies were more variable, with the most reproducible finding being a reduction in thermal thresholds in the amitriptyline-caffeine combination group. There was no effect by either drug or the drug combination on the static tactile allodynia produced by spinal nerve ligation in the ipsilateral paw. However, chronic amitriptyline administration induced a tactile hyperaesthesia in the contralateral paw at all time intervals, and this effect was exacerbated by concomitant chronic caffeine administration. The results of this study indicate that chronic administration of amitriptyline is effective in alleviating thermal hyperalgesia, but not static tactile allodynia, in the hindpaw ipsilateral to nerve injury, and the block of this effect by caffeine suggests that this effect is partially achieved through manipulation of endogenous adenosine systems. Additionally, chronic amitriptyline administration induces contralateral hyperaesthetic responses that are augmented by caffeine. Both the symptom-specific effect, and adenosine involvement in amitriptyline action may be important considerations governing its use in neuropathic pain.
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Affiliation(s)
- M J Esser
- Departments of Pharmacology and Anatomy and Neurobiology, Dalhousie University, Nova Scotia, B3H 4H7, Halifax, Canada
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15
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Tessitore A, Mattay V, Hariri A, Fera F, Callicott J, Hyde T, Chase T, Weinberger D. Dopaminergic modulation of the neocortical network that subserves facial affect recognition: A study in patients with Parkinson's disease. Neuroimage 2001. [DOI: 10.1016/s1053-8119(01)92189-5] [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: 11/26/2022] Open
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Abstract
A weight drop model of focal cerebellar injury was used to identify heat shock protein induction and motor function deficits in the anesthetized, adult male, Sprague-Dawley rat. All animals were trained on a beam walking test prior to surgery. Groups of animals received severe, mild or sham weight drop injury to the lateral/paravermal region of the cerebellum. The mild and sham-injured animals showed no motor deficits in the beam walking test, whereas animals with severe cerebellar injury showed significant motor deficits in the beam walking test that approached recovery of motor function 20 days after injury. Following severe injury, induction of heat shock protein of 27kDa was observed in Purkinje cells and in neurons of the deep cerebellar nuclei, as well as Bergmann glial cells, glial cells located in the granule cell layer and the underlying white matter. Following mild injury, heat shock protein of 27kDa induction was observed in Purkinje cells and glial cells, but not in neurons of the deep cerebellar nuclei. The labeled Purkinje cells were widely distributed in the ipsilateral cerebellar cortex. Many of the glial cells that were immunostained with heat shock protein of 27kDa co-localized with cells immunoreactive for glial fibrillary acidic protein. After severe injury, heat shock protein of 72kDa was localized mainly in granule cells at the site of the trauma and in the ipsilateral deep cerebellar nuclei whereas, after mild injury, light labeling was observed only in the granule cell layer. The results demonstrate that focal cerebellar injury has profound effects on motor behavior and induces different families of heat shock proteins in specific groups of neurons and glial cells in the cerebellum.
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Affiliation(s)
- G V Allen
- Department of Anatomy & Neurobiology, Faculty of Medicine, Dalhousie University, Nova Scotia, B3H 4H7, Halifax, Canada.
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17
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Shoulson I, Penney J, McDermott M, Schwid S, Kayson E, Chase T, Fahn S, Greenamyre JT, Lang A, Siderowf A, Pearson N, Harrison M, Rost E, Colcher A, Lloyd M, Matthews M, Pahwa R, McGuire D, Lew MF, Schuman S, Marek K, Broshjeit S, Factor S, Brown D, Feigin A, Mazurkiewicz J, Ford B, Jennings D, Dilllon S, Comella C, Blasucci L, Janko K, Shulman L, Wiener W, Bateman-Rodriguez D, Carrion A, Suchowersky O, Lafontaine AL, Pantella C, Siemers E, Belden J, Davies R, Lannon M, Grimes D, Gray P, Martin W, Kennedy L, Adler C, Newman S, Hammerstad J, Stone C, Lewitt P, Bardram K, Mistura K, Miyasaki J, Johnston L, Cha JH, Tennis M, Panniset M, Hall J, Tetrud J, Friedlander J, Hauser R, Gauger L, Rodnitzky R, Deleo A, Dobson J, Seeberger L, Dingmann C, Tarsy D, Ryan P, Elmer L, Ruzicka D, Stacy M, Brewer M, Locke B, Baker D, Casaceli C, Day D, Florack M, Hodgeman K, Laroia N, Nobel R, Orme C, Rexo L, Rothenburgh K, Sulimowicz K, Watts A, Wratni E, Tariot P, Cox C, Leventhal C, Alderfer V, Craun AM, Frey J, McCree L, McDermott J, Cooper J, Holdich T, Read B. A randomized, controlled trial of remacemide for motor fluctuations in Parkinson's disease. Neurology 2001; 56:455-62. [PMID: 11222787 DOI: 10.1212/wnl.56.4.455] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Preclinical studies suggest that glutamate antagonists help ameliorate motor fluctuations in patients with PD treated with levodopa. METHODS In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study, the authors assessed the safety, tolerability, and efficacy of the glutamate receptor blocker remacemide hydrochloride in 279 patients with motor fluctuations treated with levodopa. The primary objective was to assess the short-term tolerability and safety of four dosage levels of remacemide during 7 weeks of treatment. Patients were also monitored with home diaries and the Unified PD Rating Scale (UPDRS) to collect preliminary data on treatment efficacy. RESULTS Remacemide was well tolerated up to a dosage of 300 mg/d on a twice daily schedule and 600 mg/d on a four times daily schedule. The most common dosage-related adverse events were dizziness and nausea, as observed in previous studies of remacemide. The percent "on" time and motor UPDRS scores showed trends toward improvement in the patients treated with 150 and 300 mg/d remacemide compared with placebo-treated patients, although these improvements were not significant. CONCLUSION Remacemide is a safe and tolerable adjunct to dopaminergic therapy for patients with PD and motor fluctuations. Although this study had limited power to detect therapeutic effects, the observed improvement is consistent with studies of non-human primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian signs and symptoms. Additional studies are warranted to confirm these results over an extended period of observation, and to explore the potential neuroprotective effects of remacemide in slowing the progression of PD.
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18
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Beck LA, Chase T, Le L, Evans D, Tolbert G. The personal side of technology. SCI Nurs 2000; 17:130-2. [PMID: 12037827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Affiliation(s)
- L A Beck
- Mayo Clinic, Rochester, Minnesota, USA.
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Agid Y, Ahlskog E, Albanese A, Calne D, Chase T, De Yebenes J, Factor S, Fahn S, Gershanik O, Goetz C, Koller W, Kurth M, Lang A, Lees A, Lewitt P, Marsden D, Melamed E, Michel PP, Mizuno Y, Obeso J, Oertel W, Olanow W, Poewe W, Pollak P, Tolosa E. Levodopa in the treatment of Parkinson's disease: a consensus meeting. Mov Disord 1999; 14:911-3. [PMID: 10584663 DOI: 10.1002/1531-8257(199911)14:6<911::aid-mds1001>3.0.co;2-h] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Y Agid
- INSERM U 289 & Fédération de Neurologie, Hôpital de la Salpêtrière-47, Paris, France
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Fredriksson A, Palomo T, Chase T, Archer T. Tolerance to a suprathreshold dose of L-Dopa in MPTP mice: effects of glutamate antagonists. J Neural Transm (Vienna) 1999; 106:283-300. [PMID: 10392537 DOI: 10.1007/s007020050158] [Citation(s) in RCA: 22] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Three experiments were performed to study the development and manipulation of tolerance to a suprathreshold dose of L-Dopa (20 mg/kg, s.c.) in MPTP-treated and control (saline-injected) C57 Bl/6 mice. The motor activity reinstatement effect of this dose of L-Dopa upon MPTP-treated mouse behaviour deteriorated from the 13th injection (Test Day 8) of L-Dopa onwards and reached basal level (i.e. no stimulatory effects of the drug) by the 16th administration (Test Day 10). Administration of L-Dopa to control mice reduced locomotor and rearing activity throughout the tolerance development period (Test Days 1-12) during the first hour after injection, and then increased locomotor activity during the second hour. The effects of combining either a noncompetitive, MK-801, or a competitive, CGP 40116, glutamate antagonist with L-Dopa, following tolerance development, were assessed in MPTP mice on the 23rd day of L-Dopa administration (Test Day 13). MK-801 (0.1 mg/kg, s.c.) reinstated the locomotory and rearing behaviour induced by L-Dopa; CGP 40116 did so also to a greater extent in the dose range 0.01 to 0.03 mg/kg. These results indicate that MPTP-treated mice continue to offer a useful parkinsonian model also for the examination of different aspects of the "wearing-off" phenomenon of L-Dopa tolerance and in particular the putative glutamatergic involvement. The clinical consequences may be far-reaching for the utility of L-Dopa in Parkinson's disease, whether the effects demonstrated be of a reinstatement or synergistic nature, once therapeutically adequate glutamate antagonists are more readily available.
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Affiliation(s)
- A Fredriksson
- Department of Psychiatry, University of Uppsala, Sweden
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Affiliation(s)
- Y Agid
- INSERM U 289 and Féderation de Neurologie-Hôpital de la Salpêtrière, Paris, France
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O'Mullan PJ, Buchholz SE, Chase T, Eveleigh DE. Roles of alcohol dehydrogenases of Zymomonas mobilis (ZADH): characterization of a ZADH-2-negative mutant. Appl Microbiol Biotechnol 1995. [DOI: 10.1007/bf00164772] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Abstract
The synthesis of methylmercury by
Desulfovibrio desulfuricans
LS was investigated on the basis of
14
C incorporation from precursors and the measurement of relevant enzyme activities in cell extracts. The previously observed incorporation of C-3 from serine into methylmercury was confirmed by measurement of relatively high activities of serine hydroxymethyltransferase and other enzymes of this pathway. High rates of label incorporation into methylmercury from H
14
COO
-
and H
14
CO
3
-
prompted the assay of enzymes of the acetyl coenzyme A (CoA) synthase pathway. These enzymes were found to be present but at activity levels much lower than those reported for acetogens. Propyl iodide inhibited methylmercury and acetyl-CoA syntheses to similar extents, and methylmercury synthesis was found to compete with acetyl-CoA synthesis for methyl groups. On the basis of these findings, we propose that in methylmercury synthesis by
D. desulfuricans
LS the methyl group is transferred from CH
3
-tetrahydrofolate via methylcobalamin. The methyl group may originate from C-3 of serine or from formate via the acetyl-CoA synthase pathway. These pathways are not unique to
D. desulfuricans
LS, and thus the ability of this bacterium to methylate mercury is most likely associated with the substrate specificity of its enzymes.
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Affiliation(s)
- S C Choi
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08903-0231
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25
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Abstract
The recently defined role of methylcobalamin in Hg2+ methylation by Desulfovibrio desulfuricans LS enabled us to reexamine the question of whether the principal source of methylmercury is spontaneous transmethylation or an enzymatically catalyzed process. In cell extracts of D. desulfuricans LS, over 95% of the 57Co label was associated with macromolecules rather than with free cobalamin. Both gel filtration and electrophoresis of cell extracts identified a single corrinoid protein of 40 kDa in size. This finding, in combination with the previously reported light-reversible propyl iodide inhibition of the Hg2+ methylation process, led us to propose that this 40-kDa corrinoid protein is the in vivo methyl donor in D. desulfuricans LS. Under reducing conditions, cell extracts containing the corrinoid protein produced 14CH3Hg+ from Hg2+ and 5-14CH3-tetrahydrofolate with a maximum specific activity of 0.73 nmol min-1 mg of cell protein-1. The sequence of methyl transfer was from methyltetrahydrofolate to the corrinoid protein to Hg2+. The rate of methylation versus the Hg2+ concentration followed Michaelis-Menten kinetics, with an apparent Km of 0.87 mM HgCl2. The activity was oxygen sensitive, and Hg2+ methylation was optimal at 35 degrees C and pH 6.5. The observation of saturation kinetics and the 600-fold-higher rate of Hg2+ methylation (at pH 7.0) by cell extracts, compared with transmethylation by free methylcobalamin, proved that in vivo Hg2+ methylation is an enzymatically catalyzed process.
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Affiliation(s)
- S C Choi
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08903-0231
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Frosco MB, Chase T, Macmillan JD. The effect of elastase-specific monoclonal and polyclonal antibodies on the virulence of Aspergillus fumigatus in immunocompromised mice. Mycopathologia 1994; 125:65-76. [PMID: 8028645 DOI: 10.1007/bf01371095] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [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: 01/28/2023]
Abstract
Elastase has been implicated as a potential virulence factor involved in the invasion process of the opportunistic pathogen, Aspergillus fumigatus. Monoclonal and polyclonal antibodies, known to inhibit elastase in vitro, were employed in an immunocompromised mouse model of invasive aspergillosis to determine if the antibodies could protect mice from fatal infection. Individual monoclonal antibodies, known to inhibit elastase partially (13 to 23%), or combinations of monoclonal antibodies, known to inhibit elastase 70 to 100%, were tested in the mouse model. No individual nor combination of monoclonal antibodies protected immunosuppressed, infected mice in the doses tested. Similarly, elastase-specific polyclonal antibodies, raised in mice or rabbits, did not exhibit a protective effect, nor did immunization of mice with elastase prior to immunosuppression and infection. Histological examination of the lungs of immunosuppressed, infected mice showed no amelioration of fungal invasiveness by treatment with elastase-specific monoclonal or polyclonal antibodies. However, immunocompetent mice, instilled with a spore inoculum much higher than used in the preceding studies and treated with antibodies, survived, while control mice not treated with antibodies were overwhelmed by the massive spore dose and died. Nevertheless, overall evidence suggests that elastase may not be the primary virulence factor involved in invasive pulmonary aspergillosis.
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Affiliation(s)
- M B Frosco
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, NJ 08903
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Genez AL, Staraci LC, Alexander DC, Rejda JM, Williamson VM, Chase T, Williams BG. Isolation of a tomato alcohol dehydrogenase 2-encoding cDNA using phage-promoted antibody screening of a plasmid cDNA library. Gene X 1993; 123:157-64. [PMID: 8428654 DOI: 10.1016/0378-1119(93)90119-n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [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: 01/30/2023] Open
Abstract
We describe the cloning of a cDNA encoding tomato alcohol dehydrogenase 2 (Adh2) by screening plasmid cDNA clones in phage plaques. A cDNA library constructed in a plasmid vector containing a unique SstI site at the 5' end of the cDNA insert was transferred into the SstI site of the lacZ gene of phage lambda Charon16, and screened by anti-Adh2 antibody to identify reactive plaques. Plasmid cDNA clones were recovered by SstI digestion, ligation, and transformation from phage minipreps for subsequent characterization. This system preserves the original plasmid library for subsequent screening with nucleic acid probes to identify full-length, multiple independent, or related cDNA clones not subject to the selection pressure of phage growth or lysogeny, or negative antibody reactivity. Thirty-two cDNA clones were identified with polyclonal antiserum to Adh2. Three of these reacted with monoclonal anti-Adh2 and only those three hybridized to maize adh1 sequence. One of these cDNAs, Adh31, was further characterized as encoding Adh2 by hybrid-selected translation and high sequence homology with the maize adh1 gene.
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Affiliation(s)
- A L Genez
- Plant Cell Research Institute, Inc., Dublin, CA 94568
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28
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Abstract
Elastase, a potential virulence factor from the opportunistic pathogen Aspergillus fumigatus, was purified 220-fold from culture broth by fast-performance liquid chromatography employing anion exchange (Q Sepharose fast flow), cation exchange (S Sepharose fast flow), and gel filtration (Superose 12). Purified to near homogeneity, the elastase had an apparent molecular mass of 32 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (silver stain) but a mass of about 19.1 kDa as determined by gel filtration on Superdex 75. The elastase is not glycosylated and is positively charged at neutral pH, having a pI of 8.75. Inhibition by 0.2 mM phenylmethylsulfonyl fluoride (100%) and 0.21 mM leupeptin (60%) implies that the elastase is a serine protease. However, the enzyme is also inhibited by 5 mM EDTA (100%) and 10 mM 1,10-orthophenanthroline (30%), suggesting a requirement for divalent cations. The enzyme acts optimally at pH 7.4 and 45 degrees C in 50 mM sodium borate buffer, but in Tris HCl, the pH optimum shifts to 8.8.
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Affiliation(s)
- M Frosco
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08903
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Frosco M, Fahed C, Chase T, Macmillan JD. Inhibition of Aspergillus fumigatus elastase with monoclonal antibodies produced by using denatured elastase as an immunogen. Infect Immun 1992; 60:735-41. [PMID: 1541546 PMCID: PMC257547 DOI: 10.1128/iai.60.3.735-741.1992] [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: 12/27/2022] Open
Abstract
In preparing monoclonal antibodies to the elastase from Aspergillus fumigatus, we found that the enzyme was weakly immunogenic in BALB/c mice. Antiserum titers were only 1:1,000 to 1:5,000, and hybridomas secreted nonspecific immunoglobulin M (IgM). Denaturing the elastase in 0.5% sodium dodecyl sulfate at 80 degrees C for 10 min prior to injection increased titers of antiserum against the nondenatured (native) enzyme 10-fold. Of eight hybridomas selected following immunization with the denatured enzyme, seven produced IgG reactive with the native enzyme and one produced nonspecific IgM. The nondenatured immunogen tested again yielded mainly IgM producers. Immunoblots and enzyme-linked immunosorbent assay showed that the IgG monoclonal antibodies were reactive with both the denatured and nondenatured fungal elastases; none cross-reacted with human neutrophil elastase, porcine pancreatic elastase, or Pseudomonas elastase. Elastase-specific polyclonal antibody produced in mice inhibited elastase activity beginning at a molar ratio (antibody to elastase) of 4:1, and activity was completely inhibited at 14.5:1. Some individual monoclonal antibodies partially inhibited elastase, but certain pairs, at a molar ratio of each antibody to elastase of 5.4:1, acted synergistically to inhibit the activity completely.
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Affiliation(s)
- M Frosco
- Department of Biochemistry and Microbiology, Cook College, Rutgers University, New Brunswick, New Jersey 08903
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30
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Wisman E, Koornneef M, Chase T, Lifshytz E, Ramanna MS, Zabel P. Genetic and molecular characterization of an Adh-1 null mutant in tomato. Mol Gen Genet 1991; 226:120-8. [PMID: 2034210 DOI: 10.1007/bf00273595] [Citation(s) in RCA: 13] [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] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Treatment of tomato seeds with ethyl methanesulphonate (EMS) followed by allyl alcohol selection of M2 seeds has led to the identification of one plant (B15-1) heterozygous for an alcohol dehydrogenase (Adh) null mutation. Genetic analysis and expression studies indicated that the mutation corresponded to the structural gene of the Adh-1 locus on chromosome 4. Homozygous Adh-1 null mutants lacked ADH-1 activity in both pollen and seeds. Using an antiserum directed against ADH from Arabidopsis thaliana, which cross-reacts with ADH-1 and ADH-2 proteins from tomato, no ADH-1 protein was detected in seeds of the null mutant. Northern blot analysis showed that Adh-1 mRNA was synthesized at wild-type levels in immature seeds of the null mutant, but dropped to 25% in mature seeds. Expression of the Adh-2 gene on chromosome 6 was unaffected. The potential use of the Adh-1 null mutant in selecting rare transposon insertion mutations in a cross with "mutable" Adh-1+ tomato lines is discussed.
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Affiliation(s)
- E Wisman
- Department of Molecular Biology, Agricultural University, Wageningen, The Netherlands
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31
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Jacobowitz DM, Chase T. In memoriam--Thomas L. O'Donohue. Synapse 1988; 2:185. [PMID: 3062830 DOI: 10.1002/syn.890020302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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32
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Abstract
Mannitol-1-phosphate dehydrogenase was purified to homogeneity, and some chemical and physical properties were examined. The isoelectric point is 4.19. Amino acid analysis and polyacrylamide-gel electrophoresis in presence of SDS indicate a subunit Mr of about 22,000, whereas gel filtration and electrophoresis of the native enzyme indicate an Mr of 45,000. Thus the enzyme is a dimer. Amino acid analysis showed cysteine, tyrosine, histidine and tryptophan to be present in low quantities, one, three, four and four residues per subunit respectively. The zinc content is not significant to activity. The enzyme is inactivated (greater than 99%) by reaction of 5,5'-dithiobis-(2-nitrobenzoate) with the single thiol group; the inactivation rate depends hyperbolically on reagent concentration, indicating non-covalent binding of the reagent before covalent modification. The pH-dependence indicated a pKa greater than 10.5 for the thiol group. Coenzymes (NAD+ and NADH) at saturating concentrations protect completely against reaction with 5,5'-dithiobis-(2-nitrobenzoate), and substrates (mannitol 1-phosphate, fructose 6-phosphate) protect strongly but not completely. These results suggest that the thiol group is near the catalytic site, and indicate that substrates as well as coenzymes bind to free enzyme. Dissociation constants were determined from these protective effects: 0.6 +/- 0.1 microM for NADH, 0.2 +/- 0.03 mM for NAD+, 9 +/- 3 microM for mannitol 1-phosphate, 0.06 +/- 0.03 mM for fructose 6-phosphate. The binding order for reaction thus may be random for mannitol 1-phosphate oxidation, though ordered for fructose 6-phosphate reduction. Coenzyme and substrate binding in the E X NADH-mannitol 1-phosphate complex is weaker than in the binary complexes, though in the E X NADH+-fructose 6-phosphate complex binding is stronger.
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33
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Abstract
Cleavage of choline to trimethylamine and acetaldehyde by extracts of Proteus mirabilis requires both particulate and soluble protein fractions, K+, and a bound divalent metal cation. The reaction shows a long lag period, abolished only by preincubation of the particulate fraction in the complete reaction system. The two-carbon fragment produced is acetaldehyde; choline cleavage appears to be tightly coupled to dismutation of the acetaldehyde to ethanol and acetate, as indicated by stimulation by NAD+, ADP, and Fe2+ and inhibition by reagents reacting with acetaldehyde. The system is thus similar to that previously described in anaerobes (Desulfovibrio, Clostridium). Attempts to demonstrate a cobamide coenzyme requirement (as in the similar ethanolamine ammonia-lyase reaction) were unsuccessful; the reaction was carried out by fractions devoid of vitamin B12 activity (not supporting growth of Lactobacillus leichmannii) and insensitive to light.
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Abstract
Because the severity of memory disorders exhibited by neuropsychiatric patients overshadows other cognitive deficiencies, we explored the visuoperceptual and constructive abilities of patients with Alzheimer's (AD) or Huntington's (HD) disease. The tasks assessed directional sense with reference to egocentric space, as well as visuodiscriminative and constructive skills of patients and matched controls. A double dissociation was found: the performance of patients with AD was found to be significantly impaired on tasks involving extrapersonal perception and construction but not on the test of egocentric space. In contrast, visuoconstructive performance by patients with HD was not significantly impaired, while salient deficits were apparent when manipulation of personal space was required. These differential patterns of defects may have been aligned with neuropathologic changes in different cortical and subcortical structures, respectively, in patients with AD and HD.
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35
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Kothary MH, Chase T, Macmillan JD. Correlation of elastase production by some strains of Aspergillus fumigatus with ability to cause pulmonary invasive aspergillosis in mice. Infect Immun 1984; 43:320-5. [PMID: 6360904 PMCID: PMC263429 DOI: 10.1128/iai.43.1.320-325.1984] [Citation(s) in RCA: 165] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Seventy-five strains of Aspergillus fumigatus were screened for production of elastase in liquid and agar media containing elastin in yeast carbon base buffered with 0.05 M borate, pH 7.6. Of 71 strains which cleared elastin in agar plates, 33 produced elastase in liquid medium, as measured spectrophotometrically with elastin-Congo red. Six strains producing elastase and four nonproducers were tested for ability to cause invasive aspergillosis in immunocompromised mice (six mice per strain). All 36 mice exposed to elastase-producing strains died within 48 to 96 h. Lung tissue from dead mice showed hyphae and necrosis of the alveoli. Lungs of mice exposed to spores of strains not producing elastase showed few germinated spores and no destruction of alveoli. These results indicate that elastase may be significant in the invasion process.
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36
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37
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Cannistraro VJ, Borack LI, Chase T. Subunit structure and kinetic properties of L-beta-hydroxy acid dehydrogenase of Drosophila. Biochim Biophys Acta 1979; 569:1-5. [PMID: 37912 DOI: 10.1016/0005-2744(79)90074-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
L-beta-hydroxyacid dehydrogeanse (L-gulonate:NAD+ 3-oxidoreductase, EC 1.1.1.45) of Drosophila is made up of two non-identical subunits with molecular weights of 40 000 and 23 500. Michaelis constants calculated at saturating concentrations of the other substrate were 0.13 mM for NAD+, 0.85 mM for L-gulonate, 14.8 mM for L-beta-hydroxybutyrate; dissociation constants (Kia) were 2.8 mM for L-gulonate, 22 mM for L-beta-hydroxybutyrate. The maximum velocity with L-gulonate as substrate was ten-fold greater than with beta-hydroxybutyrate. As product inhibitors, both NADH and acetoacetate are competitive vs. both substrates, suggesting a rapid equilibrium random mechanism.
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38
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Sheiman MI, Macmillan JD, Miller L, Chase T. Coordinated action of pectinesterase and polygalacturonate lyase complex of Clostridium multifermentans. Eur J Biochem 1976; 64:565-72. [PMID: 1278173 DOI: 10.1111/j.1432-1033.1976.tb10336.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The polygalacturonate lyase and pectinesterase activities of Clostridium multifermentans, both produced extracellularly when the organism grows on pectin or polygalacturonate, have been suggested to be associated in a single complex. Both enzymic sites act on their respective substrates by single-chain action patterns, as shown by equivalent release of terminal tritium label and total product throughout the reaction. From these results, the Km and V of the lyase, and the amount of lyase activity present, we calculate the steady-state concentration of lyase substrate expected during action of the two sites on pectin if the sites are independent. No such steady-state concentration of lyase substrate was observed. Therefore, we conclude that the two types of active site act in a coordinated manner; the polysaccharide chain passes from the esterase site to the lyase site without intermediate dissociation and rebinding. This 'molecular disassembly line' constituted by the two sites may represent a system of general significance in synthesis and degradation of biological polymers.
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Abstract
The ability of orally administered caffeine to modify the antiparkinsonian efficacy of levodopa of piribedil, a putative dopamine receptor against, was studied in six patients. At doses that induced unequivocal central nervous system stimulation, caffeine produced no change in the therapeutic response to either antiparkinsonian agent. On the other hand, patients with levodopa dyskinesias reported an increase in the duration of their involuntary movements with caffeine coadministration. Since caffeine is known to stimulate both dopaminergic mechanisms and motor activity in the experimental animal, the results of this study cast doubt on the value of these factors as predictors of therapeutic efficacy in parkinsonian patients.
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Padhi SB, Eikenberry EF, Chase T. Electrophoresis of the proteins of the nuclear polyhedrosis virus of Porthetria dispar. Intervirology 1974; 4:333-45. [PMID: 4619113 DOI: 10.1159/000149868] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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43
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Savage J, Chase T, Macmillan JD. Population changes in enteric bacteria and other microorganisms during aerobic thermophilic windrow composting. Appl Microbiol 1973; 26:969-74. [PMID: 4203338 PMCID: PMC379941 DOI: 10.1128/am.26.6.969-974.1973] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Composting of wastes from swine feeding operations was studied. The effects of the frequency of turning the wastes and addition of straw to improve the physical structure were studied to determine the most effective technique to rapidly increase the temperature and, consequently, destroy coliforms and Salmonella. Four different treatments were studied; the results showed that, with addition of 5% (wt/wt) straw and mechanical turning of the compost 20 times per week, the temperature reached 60 C within 3 days and enteric bacteria were destroyed within 14 days.
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Abstract
Fatty acids in the lipids of 19 marine and terrestrial nitrifying bacteria have been analyzed. Ammonia-oxidizing bacteria have a very simple acid composition; palmitic and palmitoleic acid account for 96 to 100% of the total acids. The fatty acids of nitrite-oxidizing bacteria cover a wider range, from C(14) to C(19), but from two to four acids still account for more than 80% of the total acids. Branched iso- and anteiso-acids are present in traces only in 2 of the 19 bacteria. The chemical and morphological similarity between blue-green algae and these bacteria is discussed.
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45
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Chase T, Shaw E. Comparison of the esterase activities of trypsin, plasmin, and thrombin on guanidinobenzoate esters. Titration of the enzymes. Biochemistry 1969; 8:2212-24. [PMID: 4239491 DOI: 10.1021/bi00833a063] [Citation(s) in RCA: 373] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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46
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Abstract
The pyruvate formate-lyase activity of extracts of Escherichia coli is stimulated and the dilution effect is abolished by the addition of pyruvate to the extract. The activity can be purified fourfold from pyruvate-supplemented extracts by isoelectric precipitation under anaerobic conditions. The activity of extracts not supplemented with pyruvate has been separated into two fractions by treatment with protamine sulfate-fraction PS, the soluble portion, and fraction N, an extract of the precipitate formed upon the addition of protamine sulfate. After treatment of these fractions with charcoal, pyruvate formate-lyase activity is stimulated by the addition of S-adenosylmethionine. When sodium pyruvate is added to the crude extract before the fractionation, fraction PS has full enzymatic activity and is not stimulated by fraction N or by S-adenosylmethionine. Incubation of the inactive fractions with pyruvate and S-adenosylmethionine in the absence of other substrates similarly results in a highly active preparation, not subject to the "dilution effect" obtained when the fractions are added separately to the assay. These observations suggest that the component in the protamine supernatant fraction is activated by the other fraction and that S-adenosylmethionine and pyruvate are required for the activation reaction. The activating factor present in the protamine precipitate fraction may be further purified by heating for 10 min at 100 C under H(2) atmosphere. The yield of this factor from crude extract is not affected by activation of the pyruvate formate-lyase of the extract, indicating that the factor acts catalytically. The requirement for pyruvate is only partially satisfied by alpha-ketobutyrate and not at all by other alpha-keto acids, acetyl phosphate, or adenosine triphosphate. The rate of activation is maximal at 0.01 m sodium pyruvate and 3 x 10(-4)mS-adenosylmethionine; it is linearly dependent on the amount of activating factor added. The rate of activation is the same when the activation reaction is initiated by addition of any of the four required components, indicating that no slow step of activation can be carried out by any three of the components. A similar pyruvate formate-lyase system was found in extracts of the methionine/B(12) autotroph 113-3, grown with methionine supplement, indicating that vitamin B(12) derivatives do not participate in the system.
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47
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Mayer GG, Chase T, Farvar B, Waidh MA, Longo F, Karp F, Zinsser HH. Metabolic studies on the formation of calcium oxalate stones, with special emphasis on vitamin B6 and uric acid metabolism. Bull N Y Acad Med 1968; 44:28-44. [PMID: 5239150 PMCID: PMC1749976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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