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Bates JW, Myatt JF, Shaw JG, Follett RK, Weaver JL, Lehmberg RH, Obenschain SP. Mitigation of cross-beam energy transfer in inertial-confinement-fusion plasmas with enhanced laser bandwidth. Phys Rev E 2018; 97:061202. [PMID: 30011586 DOI: 10.1103/physreve.97.061202] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Indexed: 11/07/2022]
Abstract
Cross-beam energy transfer (CBET) is a significant energy-loss mechanism in directly driven inertial-confinement-fusion (ICF) targets. One strategy for mitigating CBET is to increase the bandwidth of the laser light, thereby disrupting the resonant three-wave interactions that underlie this nonlinear scattering process. Here, we report on numerical simulations performed with the wave-based code lpse that show a significant reduction in CBET for bandwidths of 2-5 THz (corresponding to a normalized bandwidth of 0.2%-0.6% at a laser wavelength of 351nm) under realistic plasma conditions. Such bandwidths are beyond those available with current high-energy lasers used for ICF, but could be achieved using stimulated rotation Raman scattering in diatomic gases like nitrogen.
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Affiliation(s)
- J W Bates
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - J F Myatt
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada T6G1H9
| | - J G Shaw
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R K Follett
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J L Weaver
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - R H Lehmberg
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - S P Obenschain
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
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2
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Opachich YP, Heeter RF, Barrios MA, Garcia EM, Craxton RS, King JA, Liedahl DA, McKenty PW, Schneider MB, May MJ, Zhang R, Ross PW, Kline JL, Moore AS, Weaver JL, Flippo KA, Perry TS. Capsule implosions for continuum x-ray backlighting of opacity samples at the National Ignition Facility. Phys Plasmas 2017; 24:063301. [PMID: 29104422 PMCID: PMC5648568 DOI: 10.1063/1.4985076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/09/2017] [Indexed: 06/07/2023]
Abstract
Direct drive implosions of plastic capsules have been performed at the National Ignition Facility to provide a broad-spectrum (500-2000 eV) X-ray continuum source for X-ray transmission spectroscopy. The source was developed for the high-temperature plasma opacity experimental platform. Initial experiments using 2.0 mm diameter polyalpha-methyl styrene capsules with ∼20 μm thickness have been performed. X-ray yields of up to ∼1 kJ/sr have been measured using the Dante multichannel diode array. The backlighter source size was measured to be ∼100 μm FWHM, with ∼350 ps pulse duration during the peak emission stage. Results are used to simulate transmission spectra for a hypothetical iron opacity sample at 150 eV, enabling the derivation of photometrics requirements for future opacity experiments.
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Affiliation(s)
- Y P Opachich
- National Security Technologies, LLC, Livermore, California 94550, USA
| | - R F Heeter
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M A Barrios
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - E M Garcia
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R S Craxton
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J A King
- National Security Technologies, LLC, Livermore, California 94550, USA
| | - D A Liedahl
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P W McKenty
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - M B Schneider
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M J May
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Zhang
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - P W Ross
- National Security Technologies, LLC, Livermore, California 94550, USA
| | - J L Kline
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - A S Moore
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J L Weaver
- Naval Research Laboratory, Washington, D.C. 20375, USA
| | - K A Flippo
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - T S Perry
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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3
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Weaver JL, Arandjelovic S, Brown G, K Mendu S, S Schappe M, Buckley MW, Chiu YH, Shu S, Kim JK, Chung J, Krupa J, Jevtovic-Todorovic V, Desai BN, Ravichandran KS, Bayliss DA. Hematopoietic pannexin 1 function is critical for neuropathic pain. Sci Rep 2017; 7:42550. [PMID: 28195232 PMCID: PMC5307344 DOI: 10.1038/srep42550] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [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: 11/02/2016] [Accepted: 01/12/2017] [Indexed: 12/13/2022] Open
Abstract
Neuropathic pain symptoms respond poorly to available therapeutics, with most treated patients reporting unrelieved pain and significant impairment in daily life. Here, we show that Pannexin 1 (Panx1) in hematopoietic cells is required for pain-like responses following nerve injury in mice, and a potential therapeutic target. Panx1 knockout mice (Panx1-/-) were protected from hypersensitivity in two sciatic nerve injury models. Bone marrow transplantation studies show that expression of functional Panx1 in hematopoietic cells is necessary for mechanical hypersensitivity following nerve injury. Reconstitution of irradiated Panx1 knockout mice with hematopoietic Panx1-/- cells engineered to re-express Panx1 was sufficient to recover hypersensitivity after nerve injury; this rescue required expression of a Panx1 variant that can be activated by G protein-coupled receptors (GPCRs). Finally, chemically distinct Panx1 inhibitors blocked development of nerve injury-induced hypersensitivity and partially relieved this hypersensitivity after it was established. These studies indicate that Panx1 expressed in immune cells is critical for pain-like effects following nerve injury in mice, perhaps via a GPCR-mediated activation mechanism, and suggest that inhibition of Panx1 may be useful in treating neuropathic pain.
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Affiliation(s)
- Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Sanja Arandjelovic
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Gregory Brown
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Suresh K Mendu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Monica W Buckley
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Shaofang Shu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Jin K Kim
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Joyce Chung
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Julia Krupa
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | | | - Bimal N Desai
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
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4
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Obradović ALJ, Scarpa J, Osuru HP, Weaver JL, Park JY, Pathirathna S, Peterkin A, Lim Y, Jagodic MM, Todorovic SM, Jevtovic-Todorovic V. Silencing the α2 subunit of γ-aminobutyric acid type A receptors in rat dorsal root ganglia reveals its major role in antinociception posttraumatic nerve injury. Anesthesiology 2015; 123:654-67. [PMID: 26164299 PMCID: PMC4568754 DOI: 10.1097/aln.0000000000000767] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Neuropathic pain (NPP) is likely the result of repetitive high-frequency bursts of peripheral afferent activity leading to long-lasting changes in synaptic plasticity in the spinal dorsal horn. Drugs that promote γ-aminobutyric acid (GABA) activity in the dorsal horn provide partial relief of neuropathic symptoms. The authors examined how in vivo silencing of the GABA receptor type A (GABAA) α2 gene in dorsal root ganglia (DRG) controls NPP. METHODS After crush injury to the right sciatic nerve of female rats, the α2 GABAA antisense and mismatch oligodeoxynucleotides or NO-711 (a GABA uptake inhibitor) were applied to the L5 DRG. In vivo behavioral assessment of nociception was conducted before the injury and ensuing 10 days (n = 4 to 10). In vitro quantification of α2 GABAA protein and electrophysiological studies of GABAA currents were performed on acutely dissociated L5 DRG neurons at relevant time points (n = 6 to 14). RESULTS NPP postcrush injury of a sciatic nerve in adult female rats coincides with significant down-regulation of the α2 subunit expression in the ipsilateral DRG (approximately 30%). Selective down-regulation of α2 expression in DRGs significantly worsens mechanical (2.55 ± 0.75 to 5.16 ± 1.16) and thermal (7.97 ± 0.96 to 5.51 ± 0.75) hypersensitivity in crush-injured animals and causes development of significant mechanical (2.33 ± 0.40 to 5.00 ± 0.33) and thermal (10.80 ± 0.29 to 7.34 ± 0.81) hypersensitivity in sham animals (data shown as mean ± SD). Conversely, up-regulation of endogenous GABA via blockade of its uptake in DRG alleviates NPP. CONCLUSION The GABAA receptor in the DRG plays an important role in pathophysiology of NPP caused by sciatic nerve injury and represents promising target for novel pain therapies.
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Affiliation(s)
- Aleksandar LJ Obradović
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Physiology, University of Belgrade School of Pharmacy, Belgrade, Serbia
| | - Joseph Scarpa
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Icahn Institute for Genomics and Multiscale Biology, Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Hari P Osuru
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Janelle L Weaver
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Ji-Yong Park
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Anesthesiology and Pain Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Sriyani Pathirathna
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Alexander Peterkin
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Yunhee Lim
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Anesthesiology and Pain Medicine, Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Republic of Korea
| | - Miljenko M Jagodic
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Department of Neuroscience, University of Virginia Health System, Charlottesville, VA, USA
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5
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Oh J, Weaver JL, Karasik M, Chan LY. Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research. Rev Sci Instrum 2015; 86:083501. [PMID: 26329186 DOI: 10.1063/1.4927452] [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: 06/05/2023]
Abstract
A grid image refractometer (GIR) has been implemented at the Nike krypton fluoride laser facility of the Naval Research Laboratory. This instrument simultaneously measures propagation angles and transmissions of UV probe rays (λ = 263 nm, Δt = 10 ps) refracted through plasma. We report results of the first Nike-GIR measurement on a CH plasma produced by the Nike laser pulse (∼1 ns FWHM) with the intensity of 1.1 × 10(15) W/cm(2). The measured angles and transmissions were processed to construct spatial profiles of electron density (ne) and temperature (Te) in the underdense coronal region of the plasma. Using an inversion algorithm developed for the strongly refracted rays, the deployed GIR system probed electron densities up to 4 × 10(21) cm(-3) with the density scale length of 120 μm along the plasma symmetry axis. The resulting n(e) and T(e) profiles are verified to be self-consistent with the measured quantities of the refracted probe light.
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Affiliation(s)
- Jaechul Oh
- Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, USA
| | - J L Weaver
- Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, USA
| | - M Karasik
- Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, USA
| | - L Y Chan
- Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, USA
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6
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Kumar NN, Velic A, Soliz J, Shi Y, Li K, Wang S, Weaver JL, Sen J, Abbott SBG, Lazarenko RM, Ludwig MG, Perez-Reyes E, Mohebbi N, Bettoni C, Gassmann M, Suply T, Seuwen K, Guyenet PG, Wagner CA, Bayliss DA. PHYSIOLOGY. Regulation of breathing by CO₂ requires the proton-activated receptor GPR4 in retrotrapezoid nucleus neurons. Science 2015; 348:1255-60. [PMID: 26068853 DOI: 10.1126/science.aaa0922] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 05/06/2015] [Indexed: 12/12/2022]
Abstract
Blood gas and tissue pH regulation depend on the ability of the brain to sense CO2 and/or H(+) and alter breathing appropriately, a homeostatic process called central respiratory chemosensitivity. We show that selective expression of the proton-activated receptor GPR4 in chemosensory neurons of the mouse retrotrapezoid nucleus (RTN) is required for CO2-stimulated breathing. Genetic deletion of GPR4 disrupted acidosis-dependent activation of RTN neurons, increased apnea frequency, and blunted ventilatory responses to CO2. Reintroduction of GPR4 into RTN neurons restored CO2-dependent RTN neuronal activation and rescued the ventilatory phenotype. Additional elimination of TASK-2 (K(2P)5), a pH-sensitive K(+) channel expressed in RTN neurons, essentially abolished the ventilatory response to CO2. The data identify GPR4 and TASK-2 as distinct, parallel, and essential central mediators of respiratory chemosensitivity.
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Affiliation(s)
- Natasha N Kumar
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ana Velic
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Jorge Soliz
- Institute of Veterinary Physiology, University of Zurich, Zurich, CH-8057, Switzerland. Centre de Recherche du CHU de Québec, Département de Pédiatrie, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Sheng Wang
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA. Department of Physiology, Hebei Medical University, Shijiazhuang, Hebei, 050017, China
| | - Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Josh Sen
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA. School of Medical Sciences, University of New South Wales, New South Wales 2052, Australia. Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Roman M Lazarenko
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Nilufar Mohebbi
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Thomas Suply
- Novartis Institutes for Biomedical Research, Basel, CH-4002, Switzerland
| | - Klaus Seuwen
- Novartis Institutes for Biomedical Research, Basel, CH-4002, Switzerland
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland.
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA.
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7
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Karasik M, Weaver JL, Aglitskiy Y, Oh J, Obenschain SP. Suppression of laser nonuniformity imprinting using a thin high-z coating. Phys Rev Lett 2015; 114:085001. [PMID: 25768766 DOI: 10.1103/physrevlett.114.085001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Indexed: 06/04/2023]
Abstract
Imprinting of laser nonuniformity is a limiting factor in direct-drive inertial confinement fusion experiments, particularly when available laser smoothing is limited. A thin (∼400 Å) high-Z metal coating is found to substantially suppress laser imprint for planar targets driven by pulse shapes and intensities relevant to implosions on the National Ignition Facility while retaining low adiabat target acceleration. A hybrid of indirect and direct drive, this configuration results in initial ablation by x rays from the heated high-Z layer, creating a large standoff for perturbation smoothing.
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Affiliation(s)
- Max Karasik
- Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA
| | - J L Weaver
- Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA
| | - Y Aglitskiy
- Leidos, Inc., 11951 Freedom Drive Reston, VA 20190, USA
| | - J Oh
- RSI, 4325-B Forbes Boulevard, Lanham, Maryland 20706, USA
| | - S P Obenschain
- Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA
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8
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Morenilla-Palao C, Luis E, Fernández-Peña C, Quintero E, Weaver JL, Bayliss DA, Viana F. Ion channel profile of TRPM8 cold receptors reveals a role of TASK-3 potassium channels in thermosensation. Cell Rep 2014; 8:1571-82. [PMID: 25199828 DOI: 10.1016/j.celrep.2014.08.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/09/2014] [Accepted: 08/01/2014] [Indexed: 10/24/2022] Open
Abstract
Animals sense cold ambient temperatures through the activation of peripheral thermoreceptors that express TRPM8, a cold- and menthol-activated ion channel. These receptors can discriminate a very wide range of temperatures from innocuous to noxious. The molecular mechanism responsible for the variable sensitivity of individual cold receptors to temperature is unclear. To address this question, we performed a detailed ion channel expression analysis of cold-sensitive neurons, combining bacterial artificial chromosome (BAC) transgenesis with a molecular-profiling approach in fluorescence-activated cell sorting (FACS)-purified TRPM8 neurons. We found that TASK-3 leak potassium channels are highly enriched in a subpopulation of these sensory neurons. The thermal threshold of TRPM8 cold neurons is decreased during TASK-3 blockade and in mice lacking TASK-3, and, most importantly, these mice display hypersensitivity to cold. Our results demonstrate a role of TASK-3 channels in thermosensation, showing that a channel-based combinatorial strategy in TRPM8 cold thermoreceptors leads to molecular specialization and functional diversity.
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Affiliation(s)
- Cruz Morenilla-Palao
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain.
| | - Enoch Luis
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Carlos Fernández-Peña
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Eva Quintero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Félix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain.
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9
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Kenwood BM, Weaver JL, Bajwa A, Poon IK, Byrne FL, Murrow BA, Calderone JA, Huang L, Divakaruni AS, Tomsig JL, Okabe K, Lo RH, Cameron Coleman G, Columbus L, Yan Z, Saucerman JJ, Smith JS, Holmes JW, Lynch KR, Ravichandran KS, Uchiyama S, Santos WL, Rogers GW, Okusa MD, Bayliss DA, Hoehn KL. Identification of a novel mitochondrial uncoupler that does not depolarize the plasma membrane. Mol Metab 2013; 3:114-23. [PMID: 24634817 DOI: 10.1016/j.molmet.2013.11.005] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 11/29/2022] Open
Abstract
Dysregulation of oxidative phosphorylation is associated with increased mitochondrial reactive oxygen species production and some of the most prevalent human diseases including obesity, cancer, diabetes, neurodegeneration, and heart disease. Chemical 'mitochondrial uncouplers' are lipophilic weak acids that transport protons into the mitochondrial matrix via a pathway that is independent of ATP synthase, thereby uncoupling nutrient oxidation from ATP production. Mitochondrial uncouplers also lessen the proton motive force across the mitochondrial inner membrane and thereby increase the rate of mitochondrial respiration while decreasing production of reactive oxygen species. Thus, mitochondrial uncouplers are valuable chemical tools that enable the measurement of maximal mitochondrial respiration and they have been used therapeutically to decrease mitochondrial reactive oxygen species production. However, the most widely used protonophore uncouplers such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and 2,4-dinitrophenol have off-target activity at other membranes that lead to a range of undesired effects including plasma membrane depolarization, mitochondrial inhibition, and cytotoxicity. These unwanted properties interfere with the measurement of mitochondrial function and result in a narrow therapeutic index that limits their usefulness in the clinic. To identify new mitochondrial uncouplers that lack off-target activity at the plasma membrane we screened a small molecule chemical library. Herein we report the identification and validation of a novel mitochondrial protonophore uncoupler (2-fluorophenyl){6-[(2-fluorophenyl)amino](1,2,5-oxadiazolo[3,4-e]pyrazin-5-yl)}amine, named BAM15, that does not depolarize the plasma membrane. Compared to FCCP, an uncoupler of equal potency, BAM15 treatment of cultured cells stimulates a higher maximum rate of mitochondrial respiration and is less cytotoxic. Furthermore, BAM15 is bioactive in vivo and dose-dependently protects mice from acute renal ischemic-reperfusion injury. From a technical standpoint, BAM15 represents an effective new tool that allows the study of mitochondrial function in the absence of off-target effects that can confound data interpretation. From a therapeutic perspective, BAM15-mediated protection from ischemia-reperfusion injury and its reduced toxicity will hopefully reignite interest in pharmacological uncoupling for the treatment of the myriad of diseases that are associated with altered mitochondrial function.
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Key Words
- ANT, adenine nucleotide translocase
- Bioenergetics
- CCCP
- DNP
- ECAR, extracellular acidification rate
- FCCP
- FCCP, carbonyl cyanide p-trifluoromethoxyphenylhydrazone
- Ischemia
- Mitochondria
- OCR, oxygen consumption rate
- ROS, reactive oxygen species
- TCA cycle, tricarboxylic acid cycle
- TMPD, N,N,N′,N′-tetramethyl-p-phenylenediamine dihydrochloride
- TMRM, tetramethylrhodamine
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Affiliation(s)
- Brandon M Kenwood
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Amandeep Bajwa
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Ivan K Poon
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Frances L Byrne
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Beverley A Murrow
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Joseph A Calderone
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, USA
| | - Liping Huang
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Ajit S Divakaruni
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jose L Tomsig
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Ryan H Lo
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - G Cameron Coleman
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - Zhen Yan
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA ; Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey J Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey S Smith
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Kevin R Lynch
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Webster L Santos
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Mark D Okusa
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kyle L Hoehn
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA ; Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA ; Emily Couric Clinical Cancer Center, University of Virginia, Charlottesville, VA 22908, USA
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Kehne DM, Karasik M, Aglitsky Y, Smyth Z, Terrell S, Weaver JL, Chan Y, Lehmberg RH, Obenschain SP. Implementation of focal zooming on the Nike KrF laser. Rev Sci Instrum 2013; 84:013509. [PMID: 23387652 DOI: 10.1063/1.4789313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser (λ = 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 μm thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.
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Affiliation(s)
- D M Kehne
- Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, USA
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11
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Lohman AW, Weaver JL, Billaud M, Sandilos JK, Griffiths R, Straub AC, Penuela S, Leitinger N, Laird DW, Bayliss DA, Isakson BE. S-nitrosylation inhibits pannexin 1 channel function. J Biol Chem 2012; 287:39602-12. [PMID: 23033481 DOI: 10.1074/jbc.m112.397976] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S-nitrosylation is a post-translational modification on cysteine(s) that can regulate protein function, and pannexin 1 (Panx1) channels are present in the vasculature, a tissue rich in nitric oxide (NO) species. Therefore, we investigated whether Panx1 can be S-nitrosylated and whether this modification can affect channel activity. Using the biotin switch assay, we found that application of the NO donor S-nitrosoglutathione (GSNO) or diethylammonium (Z)-1-1(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA NONOate) to human embryonic kidney (HEK) 293T cells expressing wild type (WT) Panx1 and mouse aortic endothelial cells induced Panx1 S-nitrosylation. Functionally, GSNO and DEA NONOate attenuated Panx1 currents; consistent with a role for S-nitrosylation, current inhibition was reversed by the reducing agent dithiothreitol and unaffected by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a blocker of guanylate cyclase activity. In addition, ATP release was significantly inhibited by treatment with both NO donors. To identify which cysteine residue(s) was S-nitrosylated, we made single cysteine-to-alanine substitutions in Panx1 (Panx1(C40A), Panx1(C346A), and Panx1(C426A)). Mutation of these single cysteines did not prevent Panx1 S-nitrosylation; however, mutation of either Cys-40 or Cys-346 prevented Panx1 current inhibition and ATP release by GSNO. This observation suggested that multiple cysteines may be S-nitrosylated to regulate Panx1 channel function. Indeed, we found that mutation of both Cys-40 and Cys-346 (Panx1(C40A/C346A)) prevented Panx1 S-nitrosylation by GSNO as well as the GSNO-mediated inhibition of Panx1 current and ATP release. Taken together, these results indicate that S-nitrosylation of Panx1 at Cys-40 and Cys-346 inhibits Panx1 channel currents and ATP release.
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Affiliation(s)
- Alexander W Lohman
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia 22908, USA
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12
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Lohman AW, Weaver JL, Billaud M, Bayliss DA, Isakson BE. Complex interplay between Pannexin 1 cysteine residues and channel regulation. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1131.7] [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] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Alexander W Lohman
- Molecular Physiology and Biological PhysicsUniversity of VirginiaCharlottesvilleVA
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVA
| | | | - Marie Billaud
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVA
| | | | - Brant E Isakson
- Molecular Physiology and Biological PhysicsUniversity of VirginiaCharlottesvilleVA
- Robert M. Berne Cardiovascular Research CenterUniversity of VirginiaCharlottesvilleVA
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13
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Umbreit TH, Francke-Carroll S, Weaver JL, Miller TJ, Goering PL, Sadrieh N, Stratmeyer ME. Tissue distribution and histopathological effects of titanium dioxide nanoparticles after intravenous or subcutaneous injection in mice. J Appl Toxicol 2011; 32:350-7. [PMID: 22447616 DOI: 10.1002/jat.1700] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 04/07/2011] [Accepted: 04/20/2011] [Indexed: 11/09/2022]
Abstract
Nanoparticles can be formed following degradation of medical devices such as orthopedic implants. To evaluate the safety of titanium alloy orthopedic materials, data are needed on the long-term distribution and tissue effects of injected titanium nanoparticles in experimental animals. In this study, we evaluated the tissue distribution and histopathological effects of titanium dioxide (TiO(2)) nanoparticles (approximately 120 nm diameter) in mice after intravenous (i.v.; 56 or 560 mg kg(-1) per mouse) or subcutaneous (s.c.; 560 or 5600 mg kg(-1) per mouse) injection on two consecutive days. Animals were examined 1 and 3 days, and 2, 4, 12 and 26 weeks after the final injection. When examined by light microscopy, particle agglomerates identified as TiO(2) were observed mainly in the major filtration organs - liver, lung and spleen - following i.v. injection. Particles were still observed 26 weeks after injection, indicating that tissue clearance is limited. In addition, redistribution within the histological micro-compartments of organs, especially in the spleen, was noted. Following s.c. injection, the largest particle agglomerates were found mainly in the draining inguinal lymph node, and to a lesser extent, the liver, spleen and lung. With the exception of a foreign body response at the site of s.c. injection and the appearance of an increased number of macrophages in the lung and liver, there was no histopathological evidence of tissue damage observed in any tissue at any time point.
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Affiliation(s)
- T H Umbreit
- Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, US Food and Drug Administration, Silver Spring, MD 20903, USA.
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14
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Aglitskiy Y, Velikovich AL, Karasik M, Metzler N, Zalesak ST, Schmitt AJ, Phillips L, Gardner JH, Serlin V, Weaver JL, Obenschain SP. Basic hydrodynamics of Richtmyer-Meshkov-type growth and oscillations in the inertial confinement fusion-relevant conditions. Philos Trans A Math Phys Eng Sci 2010; 368:1739-1768. [PMID: 20211882 DOI: 10.1098/rsta.2009.0131] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In inertial confinement fusion (ICF), the possibility of ignition or high energy gain is largely determined by our ability to control the Rayleigh-Taylor (RT) instability growth in the target. The exponentially amplified RT perturbation eigenmodes are formed from all sources of the target and radiation non-uniformity in a process called seeding. This process involves a variety of physical mechanisms that are somewhat similar to the classical Richtmyer-Meshkov (RM) instability (in particular, most of them are active in the absence of acceleration), but differ from it in many ways. In the last decade, radiographic diagnostic techniques have been developed that made direct observations of the RM-type effects in the ICF-relevant conditions possible. New experiments stimulated the advancement of the theory of the RM-type processes. The progress in the experimental and theoretical studies of such phenomena as ablative RM instability, re-shock of the RM-unstable interface, feedout and perturbation development associated with impulsive loading is reviewed.
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Affiliation(s)
- Y Aglitskiy
- Science Applications International Corporation, McLean, VA 22150, USA
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15
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Aglitskiy Y, Karasik M, Velikovich AL, Serlin V, Weaver JL, Schmitt AJ, Obenschain SP, Metzler N, Zalesak ST, Gardner JH, Oh J, Harding EC. Stability of a shock-decelerated ablation front. Phys Rev Lett 2009; 103:085002. [PMID: 19792732 DOI: 10.1103/physrevlett.103.085002] [Citation(s) in RCA: 3] [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: 03/23/2009] [Indexed: 05/28/2023]
Abstract
Experimental study of a shock-decelerated ablation front is reported. A planar solid plastic target is accelerated by a laser across a vacuum gap and collides with a lower-density plastic foam layer. While the target is accelerated, a fast Rayleigh-Taylor (RT) growth of the seeded single-mode perturbation at the ablation front is observed. After the collision, the velocity of the ablation front is seen to remain constant. The reshock quenches the RT growth but does not trigger any Richtmyer-Meshkov growth at the ablation front, which is shown to be consistent with both theory and simulations.
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Affiliation(s)
- Y Aglitskiy
- Science Applications International Corporation, McLean, Virginia 22150, USA
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16
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Weaver JL, Busquet M, Colombant DG, Mostovych AN, Feldman U, Klapisch M, Seely JF, Brown C, Holland G. Experimental benchmark for an improved simulation of absolute soft-x-ray emission from polystyrene targets irradiated with the Nike laser. Phys Rev Lett 2005; 94:045002. [PMID: 15783564 DOI: 10.1103/physrevlett.94.045002] [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: 10/22/2004] [Indexed: 05/24/2023]
Abstract
Absolutely calibrated, time-resolved spectral intensity measurements of soft-x-ray emission (hnu approximately 0.1-1.0 keV) from laser-irradiated polystyrene targets are compared to radiation-hydrodynamic simulations that include our new postprocessor, Virtual Spectro. This new capability allows a unified, detailed treatment of atomic physics and radiative transfer in nonlocal thermodynamic equilibrium conditions for simple spectra from low-Z materials as well as complex spectra from high-Z materials. The excellent agreement (within a factor of approximately 1.5) demonstrates the powerful predictive capability of the codes for the complex conditions in the ablating plasma. A comparison to data with high spectral resolution (E/deltaE approximately 1000) emphasizes the importance of including radiation coupling in the quantitative simulation of emission spectra.
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Affiliation(s)
- J L Weaver
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, D.C. 20375, USA
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Affiliation(s)
- P A Hancock
- Department of Psychology, University of Central Florida, Orlando 32816, USA.
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18
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Seely JF, Brown CM, Holland GE, Hanser F, Wise J, Weaver JL, Korde R, Viereck RA, Grubb R, Judge DL. Calibration of an extreme-ultraviolet transmission grating spectrometer with synchrotron radiation. Appl Opt 2001; 40:1623-1630. [PMID: 18357156 DOI: 10.1364/ao.40.001623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The responsivity of an extreme-ultraviolet transmission grating spectrometer with silicon photodiode detectors was measured with synchrotron radiation. The spectrometer was designed to record the absolute radiation flux in a wavelength bandpass centered at 30 nm. The transmission grating had a period of 200 nm and relatively high efficiencies in the +1 and the -1 diffraction orders that were dispersed on either side of the zero-order beam. Three photodiodes were positioned to measure the signals in the zero order and in the +1 and -1 orders. The photodiodes had aluminum overcoatings that passed the desired wavelength bandpass centered at 30 nm and attenuated higher-order radiation and wavelengths longer than approximately 80 nm. The spectrometer's responsivity, the ratio of the photodiode current to the incident radiation power, was determined as a function of the incident wavelength and the angle of the spectrometer with respect to the incident radiation beam. The spectrometer's responsivity was consistent with the product of the photodiode responsivity and the grating efficiency, both of which were separately measured while removed from the spectrometer.
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Torous DK, Hall NE, Dertinger SD, Diehl MS, Illi-Love AH, Cederbrant K, Sandelin K, Bolcsfoldi G, Ferguson LR, Pearson A, Majeska JB, Tarca JP, Hewish DR, Doughty L, Fenech M, Weaver JL, Broud DD, Gatehouse DG, Hynes GM, Kwanyuen P, McLean J, McNamee JP, Parenteau M, Van Hoof V, Vanparys P, Lenarczyk M, Siennicka J, Litwinska B, Slowikowska MG, Harbach PR, Johnson CW, Zhao S, Aaron CS, Lynch AM, Marshall IC, Rodgers B, Tometsko CR. Flow cytometric enumeration of micronucleated reticulocytes: high transferability among 14 laboratories. Environ Mol Mutagen 2001; 38:59-68. [PMID: 11473389 DOI: 10.1002/em.1051] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This laboratory previously described a single-laser flow cytometric method, which effectively resolves micronucleated erythrocyte populations in rodent peripheral blood samples. Even so, the rarity and variable size of micronuclei make it difficult to configure instrument settings consistently and define analysis regions rationally to enumerate the cell populations of interest. Murine erythrocytes from animals infected with the malaria parasite Plasmodium berghei contain a high prevalence of erythrocytes with a uniform DNA content. This biological model for micronucleated erythrocytes offers a means by which the micronucleus analysis regions can be rationally defined, and a means for controlling interexperimental variation. The experiments described herein were performed to extend these studies by testing whether malaria-infected erythrocytes could also be used to enhance the transferability of the method, as well as control intra- and interlaboratory variation. For these studies, blood samples from mice infected with malaria, or treated with vehicle or the clastogen methyl methanesulfonate, were fixed and shipped to collaborating laboratories for analysis. After configuring instrumentation parameters and guiding the position of analysis regions with the malaria-infected blood samples, micronucleated reticulocyte frequencies were measured (20,000 reticulocytes per sample). To evaluate both intra- and interlaboratory variation, five replicates were analyzed per day, and these analyses were repeated on up to five separate days. The data of 14 laboratories presented herein indicate that transferability of this flow cytometric technique is high when instrumentation is guided by the biological standard Plasmodium berghei.
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Affiliation(s)
- D K Torous
- Litron Laboratories, Rochester, New York 14620, USA.
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20
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Weaver JL, McAlister WH. Vision readiness of the reserve forces of the U.S. Army. Mil Med 2001; 166:64-6. [PMID: 11197101] [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: 02/19/2023] Open
Abstract
In 1996 and 1997, the Army conducted an exercise to assess the ability to rapidly mobilize the reserve forces. In accordance with Army requirements, each soldier was evaluated to determine if he or she met vision and optical readiness standards. Of the 1,947 individuals processed through the optometry section, 40% met vision requirements without correction and 32% met vision requirements with their current spectacles. The remaining 28% required examination. A major impediment to processing reserve units for deployment is the lack of vision and optical readiness. In the mobilization for the Persian Gulf War, significant delays were incurred because of the time required to perform eye examinations and fabricate eyewear. However, as a result of this exercise, current prescriptions will be available in the event of mobilization. To ensure readiness, all units should perform such exercises periodically.
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Affiliation(s)
- J L Weaver
- 7228th USA Medical Support Unit, Clinical Care Group, American Optometric Association, St. Louis, MO, USA
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21
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Hamada S, Sutou S, Morita T, Wakata A, Asanami S, Hosoya S, Ozawa S, Kondo K, Nakajima M, Shimada H, Osawa K, Kondo Y, Asano N, Sato S, Tamura H, Yajima N, Marshall R, Moore C, Blakey DH, Schechtman LM, Weaver JL, Torous DK, Proudlock R, Ito S, Namiki C, Hayashi M. Evaluation of the rodent micronucleus assay by a 28-day treatment protocol: Summary of the 13th Collaborative Study by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Environmental Mutagen Society of Japan (JEMS)-Mammalian Mutagenicity Study Group (MMS). Environ Mol Mutagen 2001; 37:93-110. [PMID: 11246216 DOI: 10.1002/em.1017] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To examine whether micronucleus tests can be incorporated into general toxicology assays, we performed micronucleus tests applying the treatment protocols typically used in such assays. In this 13th Collaborative Study of the CSGMT, both rats and mice were tested, although rats were used in the majority of the studies. Fifteen mutagens were tested in rats, mainly by oral (p.o.) administration. Micronucleus induction was evaluated 2, 3, and 4 days, and 1, 2, 3, and 28 days after the beginning of the treatment in the peripheral blood, and at 28 days in the bone marrow. Of the 15 chemicals that induced micronuclei in rats in short-term assays, two chemicals (1,2-dimethylhydrazine.2HCl and mitomycin C) were negative in all our experiments, possibly because of insufficient dose levels. The remaining 13 were positive within the estimated dose range of a general toxicology assay, suggesting the possibility of integrating the micronucleus assay into general toxicology assays. Three patterns were observed in micronucleus induction during the period of repeated treatment: (1) gradual increases in micronucleus frequency with sequential doses, (2) a peak at 3-5 days followed by gradual decreases in micronucleus frequency with sequential doses, and (3) a rapid increase in micronucleus frequency followed by a plateau. We evaluated factors that might have been involved in those patterns, such as the spleen function, target organ exposure, extramedullary hematopoiesis, hypothermia, and hypoxia. Another factor we considered was dosage. Because the dosages employed in a general toxicity assay are usually lower than those used in short-term micronucleus assays, this discrepancy was considered the greatest potential problem for integrating the micronucleus assay into general toxicology assays. Our results indicate that the integration of the micronucleus assay into a 28-day toxicological assay is feasible. To serve this purpose, blood samples collected 4 days after the beginning of treatment and blood and bone marrow samples collected at autopsy should be examined. Furthermore, although it is recognized that mice may be suitable for performing independent micronucleus assays, we propose that rats can provide biologically important and relevant information regarding potential chemical mutagens that can be evaluated under conditions used in the conduct of general toxicology studies.
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Affiliation(s)
- S Hamada
- Central Research Laboratory, SSP Company, Ltd., Chiba, Japan.
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22
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Abstract
Development of any new assay proceeds in several phases. When an assay is intended for regular use to support regulatory decision-making, there are significant additional stages in the development process beyond the initial description of the method. In this paper we discuss some of the studies related to the development of a flow cytometric method for counting micronuclei in rodent erythrocytes. Studies related to fixation methods and conditions, standardization of DNA staining, and antibody staining are discussed. These studies, while not part of the formal description of the method, are needed as part of the preparation for the formal validation of the method. In addition, the lessons learned in transferring the method to other laboratories are briefly discussed in relation to defining the final protocol.
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Affiliation(s)
- J L Weaver
- Division of Applied Pharmacology Research, Food and Drug Administration, Laurel, Maryland, USA
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Shipp MD, Daum KM, Weaver JL, Nakagawara VB, Bailey IL, Good GW, Maizel MB, Park WL. Motorist vision policy. Optometry 2000; 71:449-53. [PMID: 15326898] [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: 04/30/2023]
Abstract
BACKGROUND The primary purpose of public policy requiring vision testing for driver license renewal is to identify individuals with functional vision impairments and, when necessary, to restrict their driving. This is based on the presumption that poor vision is causally related to poor driving and traffic crashes. METHODS The AOA Environmental and Occupational Vision Committee performed a synthesis of relevant empirical literature on policy-based research and developed potential options for enhancing traffic safety. RESULTS Presently, some states require vision testing for driver's license renewal and some do not. Regional and nationwide studies report that vision-related license renewal policies are associated with enhanced traffic safety. However, contemporary vision screening tests may be of limited value in identifying individuals with functional vision impairments. CONCLUSION The most cost-effective and valid method for identifying, treating and counseling visually impaired drivers is to require a comprehensive eye examination as a condition for driver license renewal for those with a high prevalence or high probability of vision impairment.
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Affiliation(s)
- M D Shipp
- University of Alabama at Birmingham, Birmingham, Alabama, 35294-0010, USA
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Kirby BS, Weaver JL, Amos JF, Hendrix WG, Lewis TL, Locke JC, McCall JA, Walls LL. Board certification in optometry. Optometry 2000; 71:226-32. [PMID: 10974921] [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: 04/15/2023]
Abstract
BACKGROUND In keeping with current expectations in the health care community, the purpose of the American Board of Optometric Practice (ABOP) is to enhance the quality of optometric care available to the public by fostering continued competence for practitioners through administering education and examinations for certification and re-certification. The formation of ABOP makes possible for the first time a board certification process for optometrists. METHODS The optometry model for board certification and recertification emphasizes the breadth of the profession. ABOP certification will be accomplished through a combination of examinations and high-quality, tested Board Certified Continuing Education (BCCE). Specific requirements for practitioners at various stages of their careers are presented. RESULTS Board certification provides one important mechanism for an optometrist to demonstrate commitment to quality, professionalism, and ongoing clinical competence. The optometrist benefits from high-quality continuing education designed for timeliness, importance, and breadth. The public benefits by the enhancement of continued competence within the optometric profession. Health care agencies benefit by being able to recognize providers who have elected to demonstrate their qualifications through certification. CONCLUSIONS Through board certification, optometrists will be able to demonstrate their commitment to maintaining clinical competence through a nationally uniform program, and they will be able to comply with standards that are generally recognized and required throughout the health care community.
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Affiliation(s)
- B S Kirby
- American Board of Optometric Practice, St. Louis, Missouri, USA
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26
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Abstract
The data most commonly available for the determination of macromolecular structures in solution are NOE based distance estimates and spin-spin coupling constant based dihedral angle estimates. This information is, unfortunately, inherently short-range in nature. Thus, for many multidomain proteins, little information is available to accurately position weakly interacting domains with respect to each other. Recent studies of proteins aligned in dilute liquid crystalline solvents have shown the utility of measuring anisotropic spin interactions, such as residual dipolar couplings, to obtain unique long-range structural information. In this work, the latter approach is taken to explore the relative domain orientation in a two-domain fragment from the protein barley lectin. An approach based on singular value decomposition as opposed to simulated annealing is used to directly determine order tensors for each domain from residual (15)N-(1)H dipolar couplings, and the limitations of the two approaches are discussed. Comparison of the order tensor principal axis frames as separately determined for each domain indicates that the two domains are not oriented as in the crystal structure of wheat germ agglutinin, a highly homologous protein ( approximately 95% sequence identical). Furthermore, differences in the order tensor values suggest that the two domains are not statically positioned but are experiencing different reorientational dynamics and, to a large degree, may be considered to reorient independently. Data are also presented that suggest that a specific association occurs between one domain and the lipid bicelles comprising the liquid crystal solvent.
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Affiliation(s)
- M W Fischer
- Complex Carbohydrate Research Center, University of Georgia, Athens 30602, USA
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27
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Bachman WG, Weaver JL. Comparison between anti-reflection-coated and uncoated spectacle lenses for presbyopic highway patrol troopers. J Am Optom Assoc 1999; 70:103-9. [PMID: 10457687] [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: 02/13/2023]
Abstract
BACKGROUND The use of anti-reflection coatings (AR) for spectacle lenses is steadily increasing. These ultra-thin coatings reduce reflections in lenses, increasing light transmittance about 8% (from 91% to 99%). Patient reports of crisper detail and brighter environment indicate that this perceived increase in visual function would probably be of benefit to many, including highway patrolmen who must make daily judgments on the basis of fine visual detail. METHODS Nineteen presbyopic Missouri State Highway Patrolmen (MSHP) participated in this crossover study. Subjects randomly wore Varilux Comfort progressive addition lenses in CR-39 that were uncoated or AR-coated. The AR coating was Crizal. Subjects wore each lens for 1 month, then compared the lenses directly for 1 week. Data were collected for lens scoring (both general and job specific) and lens preferences. RESULTS The AR-coated lens was found to be significantly better in most categories. Reduction in glare and reflections during the day, night, indoors, and in the patrol vehicle--as well as improvement in overall night vision--were highly significant. Eighty-nine percent of the subjects chose the Crizal-coated lenses as their overall preferred lens. CONCLUSIONS The results of this study appear to demonstrate a noticeable subjective preference for AR-coated lenses when used by a group engaged in a visually demanding occupation.
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Affiliation(s)
- W G Bachman
- University of Missouri-St. Louis School of Optometry, USA
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Sayers EW, Weaver JL, Prestegard JH. Hydrogen bonding geometry of a protein-bound carbohydrate from water exchange-mediated cross-relaxation. J Biomol NMR 1998; 12:209-222. [PMID: 9751995 DOI: 10.1023/a:1008220522409] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We present heteronuclear two-dimensional methods for the analysis of the geometry of exchangeable protons on a protein-bound carbohydrate. By using a water-selective NOESY-HSQC, we observed cross-relaxation between carbohydrate hydroxyl protons and non-exchangeable ring protons in the complex of [13C6]-alpha-methyl-D-mannopyranoside with recombinant rat mannose binding protein. Using a simple kinetic model, we were able to explain the differences in the initial slopes of the resulting cross-relaxation buildup curves in terms of the geometry of the hydroxyl protons in the bound state. The hydroxyl rotamers consistent with our cross-relaxation data fit very well with predictions based on the crystal structure of MBP bound to a mannose-rich oligosaccharide. These methods should be applicable to other systems where both ligand exchange and water exchange are fast relative to the rate of cross-relaxation.
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Affiliation(s)
- E W Sayers
- Department of Pharmacology, Yale University, New Haven, CT 06510, USA
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29
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Affiliation(s)
- J L Weaver
- Division of Applied Pharmacology Research, Office of Testing and Research, CDER, Laurel, MD, USA
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30
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Weaver JL, Contrera JF, Rosenzweig BA, Thompson KL, Faustino PJ, Strong JM, Ellison CD, Anderson LW, Prasanna HR, Long-Bradley PE, Lin KK, Zhang J, Sistare FD. An evaluation of the hemizygous transgenic Tg.AC mouse for carcinogenicity testing of pharmaceuticals. I. Evidence for a confounding nonresponder phenotype. Toxicol Pathol 1998; 26:532-40. [PMID: 9715512 DOI: 10.1177/019262339802600409] [Citation(s) in RCA: 24] [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: 11/16/2022]
Abstract
We have completed 2 26-wk studies to evaluate the hemizygous transgenic Tg.AC mouse, which has been proposed as an alternative short term model for testing carcinogenicity. We attempted to evaluate the response to the known rodent carcinogens cyclophosphamide, phenolphthalein, and tamoxifen and to the noncarcinogen chlorpheniramine following topical application. In the first study, a weak response (2/17 animals) was observed to the positive control 12-O-tetradecanoylphorbol 13-acetate (TPA in ethanol, 1.25 micrograms), and no response was observed to cyclophosphamide, phenolphthalein, or chlorpheniramine, despite evidence for skin penetration. The second study compared 1.25 micrograms and 6.25 micrograms of TPA in ethanol and acetone solutions. Tamoxifen was also evaluated in both solvents and orally. No significant response was observed to tamoxifen by skin paint or oral routes. Over 60% of the high dose TPA-treated animals showed no (0 or 1) papilloma response, and 30% of the animals each developed more than 32 papillomas. The heterogenous response to high dose TPA may be related to variability in the responsiveness of hemizygous animals. In light of these findings, further Tg.AC studies should employ homozygous animals, and the underlying cause for heterogeneity in the tumorigenic response of Tg.AC mice should be identified and eliminated.
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Affiliation(s)
- J L Weaver
- Office of Testing and Research, Food and Drug Administration, Laurel, Maryland 20708, USA
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31
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Pine PS, Weaver JL, Oravecz T, Pall M, Ussery M, Aszalos A. A semiautomated fluorescence-based cell-to-cell fusion assay for gp120-gp41 and CD4 expressing cells. Exp Cell Res 1998; 240:49-57. [PMID: 9570920 DOI: 10.1006/excr.1998.3939] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [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: 11/22/2022]
Abstract
A novel fluorescence-based method was developed to measure HIV envelope glycoprotein (env)-CD4-mediated cell fusion. This method measures the spread of a fluorescent dye as the cytosolic compartments of adjacent cells become contiguous upon cell-to-cell fusion. Calcein-labeled CD4+ Sup-T1 cells were seeded onto a monolayer of unlabeled TF228.1.16 cells, which stably express env, the gp120-gp41 complex. Changes in the following parameters were measured using a stage-scanning laser microscope: total fluorescent area, average fluorescent area, and average shape factor. Anti-CD4 monoclonal antibodies, anti-Leu3a, and OKT4E were shown to block fusion in a dose-dependent manner, while OKT4 had no effect. Aurin tricarboxylic acid, a compound that interferes with the binding of anti-Leu3a mAb and gp120 to CD4+ human peripheral blood lymphocytes, T20, a peptide that interferes with gp41, and cytochalasin D, a microfilament disrupter, all blocked fusion in a dose-dependent manner. This semiautomated assay can be used to quickly assess the effectiveness of compounds acting at different sites to block CD4 and env initiated cell-to-cell fusion.
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Affiliation(s)
- P S Pine
- Division of Applied Pharmacology Research, CDER, Food and Drug Administration, Laurel, Maryland 20708, USA.
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32
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Abstract
Plant lectins are useful targets for biophysical studies of protein-carbohydrate recognition, a process of general interest because of its many roles in human physiology. Here, nuclear magnetic resonance (NMR) based structural and carbohydrate binding data on a two-domain fragment of the normally four-domain barley lectin protein are presented. The structural data, while preliminary, clearly shows that the recombinantly produced simplified model system, called BLBC, retains a nativelike fold. However, unlike the full-length parent protein, which is dimeric, BLBC is shown by pulsed-field gradient NMR diffusion studies to be largely monomeric. Still, the fragment retains nativelike carbohydrate binding properties. These properties are examined in some detail using heteronuclear single quantum coherence (HSQC) NMR spectroscopy on a uniformly 15N-labeled sample. Ligand-induced chemical shift changes in the 1H-15N HSQC spectrum are monitored as 15N-labeled BLBC is titrated with increasing concentrations of the unlabeled carbohydrate, N,N',N"-triacetylchitotriose. Well-resolved resonances from the individual domains show that BLBC binds ligand at two distinct and independent ligand binding sites, one in each domain. Binding constants of (1.1 +/- 0.2) x 10(3) M-1 and (0.6 +/- 0.2) x 10(3) M-1 are determined for the B and C domain sites, respectively. These results are discussed in relation to ligand binding studies that have previously been carried out on a highly homologous protein, wheat germ agglutinin.
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Affiliation(s)
- J L Weaver
- Department of Chemistry, Yale University, New Haven, Connecticut 06511, USA
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33
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Aszalos A, Weaver JL. Estimation of drug resistance by flow cytometry. Methods Mol Biol 1998; 91:117-122. [PMID: 9664487 DOI: 10.1385/0-89603-354-6:117] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- A Aszalos
- Division of Applied Pharmacology Research, Office of Testing and Research, CDER, Laurel, MD, USA
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34
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Hewlett I, Lee S, Molnar J, Foldeak S, Pine PS, Weaver JL, Aszalos A. Inhibition of HIV infection of H9 cells by chlorpromazine derivatives. J Acquir Immune Defic Syndr Hum Retrovirol 1997; 15:16-20. [PMID: 9215649 DOI: 10.1097/00042560-199705010-00003] [Citation(s) in RCA: 11] [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: 02/04/2023]
Abstract
The binding between the HIV surface protein, gp120, and the CD4 coreceptor is known to be initiated by electrostatic interactions. Because of the ability of chlorpromazine to interact with proteins by charge transfer, we tested several derivatives for their ability to block binding of HIV to CD4+ cells. We have shown that 7,8-dioxo-chlorpromazine blocks binding of fluorescein isothiocyanate-labeled anti-Leu3a and rgp120 to peripheral human blood T4 cells and blocks syncytia formation between gp120- and CD4-expressing cells. We also found that 7,8-dioxo-chlorpromazine blocks HIV infectivity of H9 cells and acts synergistically with zidovudine.
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Affiliation(s)
- I Hewlett
- FDA, Center for Biological Evaluation and Research, Bethesda, Maryland, USA
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35
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Abstract
Job-related vision standards benefit both employee and employer. By comparing employees' vision to specific job requirements, workers can be better placed into positions commensurate with their visual abilities. For a company without a vision care program, a project was undertaken to determine visual standards, and the need for vision care services for employees to better meet these standards. The critical factors for performing specific visual tasks for 40 job classifications were identified through direct observation and measurement, and through worker interviews. Additionally, a sample of employees was screened to determine plant population characteristics, and to determine what percentage of employees met the newly formed standards. This study can serve as a model for the application of visual standards to the workplace and is pertinent, as "reduced vision" is increasingly defined by government as a disability.
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Affiliation(s)
- G W Good
- Ohio State University College of Optometry, Columbus 43210, USA
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36
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Weaver JL, McKinney L, Schoenlein PV, Goldenberg S, Gottesman MM, Aszalos A. MDR1/P-glycoprotein function. I. Effect of hypotonicity and inhibitors on rhodamine 123 exclusion. Am J Physiol 1996; 270:C1447-52. [PMID: 8967446 DOI: 10.1152/ajpcell.1996.270.5.c1447] [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] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The MDR1 protein (P-glycoprotein) is a membrane ATPase whose expression results in resistance to several anti-tumor drugs. It has been proposed that the MDR1 protein, in addition to its pumplike properties, can function as (Gill et al. Cell 71: 23-32, 1992; Altenberg et al. Cancer Res. 54:618-622, 1994) or mediate the activity of (Hardy et al. EMBO J. 14: 68-75, 1995) a hypotonic stress-induced Cl- current. In addition, one study found that drug transport and Cl- channel-associated functions of MRD1 were separable and mutually exclusive and that, when cells were swelled, the MDR1 protein could not transport substrate. This hypothesis was tested in four pairs of isogenic cell lines with MDR1 transfectants expression 8,000-55,000 MDR1 antibody binding sites per cell. Cytoplasmic exclusion of rhodamine 123 was used as an indicator of MDR1 function to measure the effect of hypotonic stress, MDR1 inhibitors, and Cl- channel blockers on MRD1 transport function. It was found that MDR1 activity and its inhibition by cyclosporine A or flufenamic acid were unaffected by hypotonicity alone or in combination with Cl- channel blockers.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, Food and Drug Administration, Laurel, Maryland 20708, USA
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37
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Weaver JL, Aszalos A, McKinney L. MDR1/P-glycoprotein function. II. Effect of hypotonicity and inhibitors on Cl- efflux and volume regulation. Am J Physiol 1996; 270:C1453-60. [PMID: 8967447 DOI: 10.1152/ajpcell.1996.270.5.c1453] [Citation(s) in RCA: 11] [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: 02/03/2023]
Abstract
Resistance to anti-tumor drugs can be mediated by overexpression of the multidrug resistance 1 (MDR1) protein (P-glycoprotein). In three MDR1-transfected cell lines (Gill et al. Cell 71: 23-32, 1992; Altenberg et al. Cancer Res. 54: 618-622, 1994), a hypotonic stress-induced Cl- current has been demonstrated that can be inhibited by MDR1 substrates and Cl- channel blockers. We tested the hypothesis that MDR1 expression confers additional Cl- conductance by measuring regulatory volume decrease (RVD) in four pairs of isogenic cell lines and 36Cl efflux in two cell lines with and without hypotonic stress. The kinetics of RVD and response to Cl- channel blockers were indistinguishable in MDR and parental cells. Additionally, no significant difference was seen between 36Cl efflux rate constants under hypotonic conditions between NIH/3T3 and L1210 parental and MDR cells. We conclude that, in intact cells, the expression of MDR1 does not alter the rate of volume regulation or the rate 36Cl efflux under hypotonic conditions between parental and MDR cells.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, Food and Drug Administration, Laurel, Maryland 20708, USA
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38
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Abstract
We present baseline values for 12 hematologic and 17 serum chemistry parameters collected from 22 captive lynx (Felis lynx canadensis) in December 1992, at Ronan, Montana (USA). There were no significant differences in hematologic parameters between yearlings and adults or between sexes. Lynx originally captured in the wild had significantly higher mean (+/- SE) counts of neutrophils (7.7 +/- 0.37 x 10(3) versus 7.2 +/- 0.35 x 10(3)) and lower counts of lymphocytes (1.1 +/- 0.05 x 10(3) versus 1.6 +/- 0.08 x 10(3)) compared to lynx born and raised in captivity. Yearling lynx had significantly higher values for alkaline phosphatase than adults (51.0 +/- 6.0 IU/l versus 17.5 +/- 0.8 IU/l.
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Affiliation(s)
- J L Weaver
- Northern Rockies Conservation Cooperative, Missoula, Montana 59807, USA
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39
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Abstract
Instances when T cell activation via the T cell receptor/CD3 complex is suppressed by anti-CD4 Abs are generally attributed either to the topological separation of CD4-p56lck from CD3, or their improper apposition. Photobleaching fluorescence resonance energy transfer measurements permitted direct analysis of these alternatives on human peripheral blood lymphocytes. Distinction between changes of relative antigen densities or positioning was made possible by simultaneously recording donor and acceptor fluorescence in the energy transfer experiment performed on homogeneous populations of flow-sorted cells. We show here that CD4 stays in the molecular vicinity of CD3, while anti-CD3 stimulation is suppressed by anti-CD4 or cross-linked HIV gp120. Our data suggest that cross-linking of CD4 through particular epitopes is capable of inhibiting activation driven by Abs binding to specific sites on CD3 without major topological sequestration of the Ags, in such a way that additional positive signals will also be affected. Thus, these and other related cases of negative signaling via CD4 may be interpreted in terms of functional uncoupling rather than a wide physical separation of CD4 from the T cell receptor-CD3 complex.
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Affiliation(s)
- G Szabó
- Department of Biophysics, University Medical School of Debrecen, Hungary
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40
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Szabo G, Pine PS, Weaver JL, Rao PE, Aszalos A. The L-selectin (Leu8) molecule is associated with the TcR/CD3 receptor; fluorescence energy transfer measurements on live cells. Immunol Cell Biol 1994; 72:319-25. [PMID: 7528722 DOI: 10.1038/icb.1994.48] [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: 01/25/2023]
Abstract
Several accessory molecules were shown to play important roles in T cell functions and be in close proximity to the T cell receptor (TcR/CD3). The L-selectin molecule (Leu8, LAM1-1, LECAM1) also plays an important role in lymphocyte homing and proliferation. We were interested in determining the proximity of this molecule to the TcR/CD3 complex on live peripheral human T cells. Using a fluorescence energy transfer method, designed to study individual cells, we could show that L-selectin is within 170 A of the TcR/CD3 complex. Monoclonal antibody directed against the LAM1-1 (Leu8) epitope of the L-selectin molecule suppressed the mitogenic activity of antibodies specific for various CD3 epitopes in vitro. Intracellular Ca2+ mobilization obtained with wt31 followed by cross-linking antibody or with anti-CD3 was not influenced by anti-Leu8 antibody. Also antibody directed against the LAM1-1 epitope did not influence the binding of the mitogenic antibodies, as shown by fluorescence-based flow cytometry. Therefore, we suggest that binding of TcR/CD3 bound mitogenic antibodies to accessory cell Fc receptors may be hindered by antibodies bound to the close proximity L-selectin molecules.
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Affiliation(s)
- G Szabo
- Department of Biophysics, University Medical School of Debrecen, Hungary
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41
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Abstract
It has previously been shown that crosslinking of the CD4 molecule, either with anti-Leu3a mAb or with gp120 (the HIV coat protein) plus anti-gp120 mAb, suppresses activation induced by wt31, a TcR/CD3-specific mAb. This suppression was associated with hindrance of the necessary association of the p56lck kinase bearing CD4 molecule with the TcR/CD3 complex. In this paper we demonstrate that this crosslinking-induced suppression can be bypassed by perturbing the microfilament system of CD4+ cells by pretreatment with 1 microM cytochalasin D. Using the fluorescence resonance energy transfer method, we have shown that the cytochalasin D-affected increase of mitogenesis is not due to changes in the TcR/CD3 to CD4 distance. Likewise, other membrane biophysical parameters, membrane potential and lateral diffusion of surface receptors, cannot be associated with these cytochalasin D-affected mitogenic changes. Cytochalasin D treatment elevates intracellular Ca2+ levels induced by wt31 mAb plus crosslinking and generates a TcR/CD3-dependent signal which is cyclosporin sensitive.
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Affiliation(s)
- A Aszalos
- Center for Drug Evaluations and Research, FDA, Washington, DC 20204
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42
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Abstract
We have developed an in vitro system to model the interactions of drugs used to treat transplant rejection. This system consists of stimulation of human lymphocytes with a primary mitogen (anti-T-cell receptor complex antibodies (OKT3 or wt31)) and treatment with a primary immunosuppressive drug (ISD) (Cyclosporine A (CsA) or FK-506)). This is later followed by stimulation with a secondary mitogen (Interleukin-2 or anti-CD28), and treatment with a second ISD. This system allows a variety of concentrations and compounds to be rapidly tested. We have used this system to study the effect of various compounds when used as either primary or secondary ISDs. Our results show that when CsA is used as the primary ISD, further proliferation can be inhibited by rapamycin, mycophenolic acid, or suramin. When FK-506 is the primary ISD, inhibition of proliferation by rapamycin is variable depending on the primary and secondary mitogens. If rapamycin is the primary ISD, both CsA and FK-506 show antagonistic interactions. These results suggest that the order in which combinations of ISDs are administered in transplantation may have significant effects on the clinical outcome.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, Food and Drug Administration, Washington, DC 20204
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43
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Abstract
Brief treatment of human peripheral blood lymphocytes with the potential anti-HIV compound aurintricarboxylic acid (ATA) prompts the selective release of already bound L-selectin-specific anti-Leu8 and anti-LAM1-1 antibodies from the cells. Two other anti-LAM1 antibodies, anti-LAM1-3 and anti-LAM1-5 stay antigen-bound at the same time. Interestingly, the ATA-sensitive anti-Leu8 strongly competes with the ATA-resistant anti-LAM1-3 for binding. Photobleaching fluorescence resonance energy transfer (pFRET) measurements on flow-sorted cells suggests that these two antibodies compete for the same epitope, while anti-LAM1-5-FITC and anti-Leu8-PE bind to distinct sites, although they also compete for binding. Combining the data on competition, pFRET and ATA effect, we suggest that the ATA sensitive anti-Leu8 and resistant anti-LAM1-3 bind to overlapping but non-identical epitopes. This remarkably specific effect may be exploited for designing anti-inflammatory drugs that modulate leukocyte adhesion.
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Affiliation(s)
- G Szabó
- Division of Research and Testing, F.D.A., Washington, DC 20204
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44
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Weaver JL, Szabo G, Pine PS, Gottesman MM, Goldenberg S, Aszalos A. The effect of ion channel blockers, immunosuppressive agents, and other drugs on the activity of the multi-drug transporter. Int J Cancer 1993; 54:456-61. [PMID: 7685326 DOI: 10.1002/ijc.2910540317] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [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: 01/26/2023]
Abstract
The MDRI protein is an energy-dependent transport protein responsible for the multi-drug resistance seen in many tumors. A variety of drugs have been shown to inhibit the function of this pump, including compounds known to block various ion channels. The mouse lymphoma cell line L5178Y has been transduced with the human mdrI gene. Using this cell line, we have tested a number of compounds to determine whether there is a correlation between the ability to block a specific type of ion channel, or shift membrane potential, and the ability to act as an MDR-reversing agent using the fluorescent substrates Rhodamine 123 and daunorubicin as test compounds. Our results show no apparent correlation between the ability to block a specific ion channel and reversal of MDR transport ability. We have found active MDR inhibitors in compounds that affect K+, Na+, Ca++, H+, but not Cl- channels. Our data suggest that Cl- channel activity may be distinct from MDR activity. Several immunosuppressive compounds and analogs were also tested and found to be active reversing agents. Measurements suggest a significant difference in resting membrane potential between the L5178YvMDR line and the L5178Y parental cell line used in these experiments. No correlation was found between the ability of drugs to alter membrane potential and to inhibit MDR transport activity. Our results suggest that MDR transport function may be independent of the physiological movement of ions and show that a wide variety of compounds can inhibit MDR transport.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, Food and Drug Administration, Washington, DC 20204
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45
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Szabò G, Pine PS, Weaver JL, Rao PE, Aszalos A. CD4 changes conformation upon ligand binding. The Journal of Immunology 1992. [DOI: 10.4049/jimmunol.149.11.3596] [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
Aurintricarboxylic acid (ATA) has been shown to block the binding site for both HIV gp120 and mAb anti-Leu 3a on CD4. We have unexpectedly found that brief treatment with > or = 1 micrograms/ml ATA rapidly disengages another mAb, OKT4E, after it has been bound to CD4 on human PBL. OKT4E is specific for a discontinuous epitope overlapping the MHC class II-binding region in the N-terminal CD4 domain. Interestingly, among 10 other mAb tested, only anti-Leu 8, specific for a leukocyte homing receptor is also quickly released from the cells by ATA treatment. Disengagement of the OKT4E mAb is also seen on a CD4-positive cell line (HPB-ALL) and with recombinant soluble CD4 (sCD4) bound to immobilized OKT4E. In all of these cases, disengagement is prevented if OKT4E is cross-linked, or the Leu 3a site is blocked by the mAb, but not by gp120. Photobleaching fluorescence resonance energy transfer (pFRET) measurements suggest that OKT4E is released as an indirect consequence of ATA-evoked conformational changes of CD4. Similar changes were detected as a result of gp120 binding to PBL. These data raise the possibility of a novel type of immunomodulation: induced disengagement of a bound ligand from its Ag.
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Affiliation(s)
- G Szabò
- Center for Drug Evaluation and Research, FDA, Washington, DC 20204
| | - P S Pine
- Center for Drug Evaluation and Research, FDA, Washington, DC 20204
| | - J L Weaver
- Center for Drug Evaluation and Research, FDA, Washington, DC 20204
| | - P E Rao
- Center for Drug Evaluation and Research, FDA, Washington, DC 20204
| | - A Aszalos
- Center for Drug Evaluation and Research, FDA, Washington, DC 20204
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46
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Szabò G, Pine PS, Weaver JL, Rao PE, Aszalos A. CD4 changes conformation upon ligand binding. J Immunol 1992; 149:3596-604. [PMID: 1431129] [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: 12/27/2022]
Abstract
Aurintricarboxylic acid (ATA) has been shown to block the binding site for both HIV gp120 and mAb anti-Leu 3a on CD4. We have unexpectedly found that brief treatment with > or = 1 micrograms/ml ATA rapidly disengages another mAb, OKT4E, after it has been bound to CD4 on human PBL. OKT4E is specific for a discontinuous epitope overlapping the MHC class II-binding region in the N-terminal CD4 domain. Interestingly, among 10 other mAb tested, only anti-Leu 8, specific for a leukocyte homing receptor is also quickly released from the cells by ATA treatment. Disengagement of the OKT4E mAb is also seen on a CD4-positive cell line (HPB-ALL) and with recombinant soluble CD4 (sCD4) bound to immobilized OKT4E. In all of these cases, disengagement is prevented if OKT4E is cross-linked, or the Leu 3a site is blocked by the mAb, but not by gp120. Photobleaching fluorescence resonance energy transfer (pFRET) measurements suggest that OKT4E is released as an indirect consequence of ATA-evoked conformational changes of CD4. Similar changes were detected as a result of gp120 binding to PBL. These data raise the possibility of a novel type of immunomodulation: induced disengagement of a bound ligand from its Ag.
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Affiliation(s)
- G Szabò
- Center for Drug Evaluation and Research, FDA, Washington, DC 20204
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47
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Abstract
Several tannins with anti-HIV activity have been described previously (Nonaka et al., J Nat Prod 53: 587-595, 1990). We have shown that the tannins chebulinic acid and punicalin were able to block the binding of HIV rgp120 to CD4. These compounds were not toxic to stimulated human peripheral blood lymphocytes at concentrations ten times above their maximal effective concentration.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, Food and Drug Administration, Washington, DC 20204
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48
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Szabà G, Pine PS, Weaver JL, Kasari M, Aszalos A. Epitope mapping by photobleaching fluorescence resonance energy transfer measurements using a laser scanning microscope system. Biophys J 1992; 61:661-70. [PMID: 1380319 PMCID: PMC1260284 DOI: 10.1016/s0006-3495(92)81871-4] [Citation(s) in RCA: 51] [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: 12/26/2022] Open
Abstract
The donor photobleaching method (T. M. Jovin and D. J. Arndt-Jovin. 1989. Annu. Rev. Biophys. Biophys. Chem. 18:271-308.) has been adapted to an ACAS 570 (laser scanning microscope) system to measure fluorescence resonance energy transfer (FRET) on individual human peripheral blood T cells. Photobleaching was completed in approximately 100 ms in our case and it followed double-exponential kinetics. The energy transfer efficiency (E) was approximately 20% between the CD4 epitopes OKT4-FITC and Leu-3a-PE as well as between OKT4E-FITC and OKT4-PE. E was approximately 8% between OKT4-FITC and Leu-4-PE (alpha CD3) and barely detectable (approximately 4%) from OKT4-FITC to Leu-5b-PE (alpha CD2). The E values obtained by the photobleaching method were highly reproducible both in repeated measurement of identical samples and in experiments with different batches of cells and were in agreement with the flow cytometric donor quenching measurements. As expected, E measured between primary and secondary layers of antibodies increased (from approximately 14% to approximately 28%) when F(ab')2 fragments were substituted for whole antibody molecules as the donor. On a T cell line we mapped the distance between the idiotypic determinant of the T cell receptor (TcR) and the Leu-4 epitope of CD3 as proximal as E = 28%, as compared to E = 4% between a framework TcR epitope and Leu-4. In the latter case, however, approximately 40% less Leu-4 was bound suggesting that the antigen binding site of TcR is in close proximity with one of the two CD3 epsilon chains, which hence are not equivalent.
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MESH Headings
- Antibodies, Monoclonal
- Cell Line
- Epitopes/analysis
- Fluorescein-5-isothiocyanate
- Humans
- Immunoglobulin Fab Fragments
- Lasers
- Leukemia, T-Cell
- Lymphocytes/immunology
- Microscopy, Electron, Scanning/methods
- Microscopy, Fluorescence/methods
- Receptors, Antigen, T-Cell/analysis
- Receptors, Antigen, T-Cell/immunology
- Spectrometry, Fluorescence
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Affiliation(s)
- G Szabà
- Center for Drug Evaluation and Research, Food and Drug Administration, Washington, DC 20204
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49
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Weaver JL, Pine PS, Aszalos A, Schoenlein PV, Currier SJ, Padmanabhan R, Gottesman MM. Laser scanning and confocal microscopy of daunorubicin, doxorubicin, and rhodamine 123 in multidrug-resistant cells. Exp Cell Res 1991; 196:323-9. [PMID: 1680064 DOI: 10.1016/0014-4827(91)90267-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [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: 12/28/2022]
Abstract
The multidrug-resistant gene (MDR1) encodes an energy-dependent drug efflux pump (P-glycoprotein) for many anti-cancer drugs. We have studied the intracellular distribution of rhodamine 123 (R123), daunorubicin (DN), and doxorubicin (DOX) in cells expressing a human MDR1 gene. The distribution of these fluorescent drugs was measured by laser scanning microscopy and confocal microscopy. We devised a new method for analysis of fluorescence line scan data to determine the intracellular distribution of fluorescent probes. This method and confocal microscopy showed that R123, DN, and DOX are localized to both plasma membrane and intracellular compartments in multidrug-resistant cells. When the cells are treated with verapamil, an inhibitor of the multidrug transporter, the amount of DOX, DN, and R123 associated with the cell rises. After inhibition, the relative distribution of DOX and DN between the cell surface and intracellular structures does not change dramatically. However, R123 tends to relocalize to intracellular sites from predominantly plasma membrane sites, indicating that this dye behaves differently than the anti-cancer drugs. These results show the subcellular distributions of R123, DN, and DOX in plasma membrane, cytoplasm, and intracellular membrane systems, but do not allow definitive distinctions among existing models of how P-glycoprotein affects the distribution of drugs.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, CDER, HFD-471, Food and Drug Administration, Washington, D.C. 20204
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50
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Weaver JL, Pine PS, Aszalos A. Comparison of the in vitro and biophysical effects of cyclosporine A, FK-506, and mycophenolic acid on human peripheral blood lymphocytes. Immunopharmacol Immunotoxicol 1991; 13:563-76. [PMID: 1723084 DOI: 10.3109/08923979109019723] [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: 12/28/2022]
Abstract
The immunosuppressive drugs FK-506 and mycophenolic acid (MPA) have recently been described, but their mode(s) of action are not well understood. We have compared them to cyclosporine A (CsA) in several assays. We have shown that CsA (1 microgram/ml), MPA (0.1 microgram/ml), and FK-506 (0.5 microgram/ml) all induce a state of unresponsiveness to anti-CD3 stimulation as measured by [3H]-thymidine uptake. This suggests that the target of these drugs may be present only after mitogenic stimulation. These drugs also cause a hyperpolarization of the plasma membrane of lymphocytes. This effect is blocked by quinine or verapamil. All three immunosuppressors only slightly modulate the increase in intracellular Ca++ caused by Con-A or by anti-CD3 stimulation but do not affect Ca++ levels alone. They also decrease expression of IL-2 receptors on alpha CD3-stimulated lymphocytes. Similarities in their modes of action, as measured by these biophysical and cell biological tests, indicate the possibility that these three drugs will show similarities in their clinical performance.
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Affiliation(s)
- J L Weaver
- Division of Research and Testing, Food and Drug Administration, Washington, DC 20205
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