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Moraes LC, Lang PM, Arcanjo RA, Rampelotto PH, Fatturi-Parolo CC, Ferreira MBC, Montagner F. Microbial ecology and predicted metabolic pathways in various oral environments from patients with acute endodontic infections. Int Endod J 2020; 53:1603-1617. [PMID: 33448446 DOI: 10.1111/iej.13389] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 08/11/2020] [Indexed: 01/17/2023]
Abstract
AIM To assess in a cross-sectional clinical study the effect of antibiotics on the diversity, structure and metabolic pathways of bacterial communities in various oral environments in patients with acute primary infections. METHODOLOGY Samples of saliva (SA), supragingival biofilm (SB) and from the pulp cavity (PC) were collected from teeth with acute primary infections and then grouped according to previous use of antibiotics (NoAtb = no antibiotics [n = 6]; Atb = antibiotics [n = 6]). DNA sequencing was conducted using MiSeq (Illumina, San Diego, CA, USA). The V1-V3 hyper-variable region of the 16S rRNA gene was amplified. A custom Mothur pipeline was used for 16S rRNA processing. Subsequent analyses of the sequence dataset were performed in R (using vegan, phyloseq and ggplot2 packages) or QIIME. RESULTS Twelve patients aged from 22 to 56 years were recruited. Participants in the Atb group had taken the beta-lactamics amoxicillin (5/6) or cephalexin (1/6) for 2-3 days. A total of 332 bacterial taxa (OTUs) were identified, belonging to 120 genera, 60 families and nine phyla. Firmicutes (41%) and Bacteroidetes (38%) were the most abundant phyla in all samples. Taxa clustered significantly by oral site (PCoA analysis; P < 0.05, ANOSIM). Use of antibiotics had little effect on this clustering. However, SA, SB and PC had different degrees of richness, diversity and evenness. The greatest diversity was observed in SB samples and the least diversity was observed in PC samples. Metabolic prediction identified 163 pathways and previous use of antibiotics had a major effect on the estimated functional clustering in SA and PC samples. CONCLUSION The ecological niche had a strong influence on the bacterial content of samples from various oral sites. Previous exposure to antibiotics may exert an effect on the phylogenetic composition of SA. Metabolic pathways appear to be modulated by antimicrobial agents in SA and PC samples. The dynamics of host/microbial interactions in the apical region and the functional ecology of the infected pulp cavity should be revisited.
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Affiliation(s)
- L C Moraes
- Programa de Pós-graduação em Odontologia, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - P M Lang
- Programa de Pós-graduação em Odontologia, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Curso de Odontologia, Universidade Regional Integrada do Alto Uruguai e das Missões, Erechim, Brazil
| | - R A Arcanjo
- Programa de Pós-graduação em Ciências Biológicas: Farmacologia e Terapêutica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - P H Rampelotto
- Laboratório Experimental de Hepatologia e Gastroenterologia (LEHG), Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil.,Laboratório de Pesquisa em Resistência Bacteriana (LABRESIS), Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, Brazil
| | - C C Fatturi-Parolo
- Programa de Pós-graduação em Odontologia, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - M B C Ferreira
- Departamento de Odontologia Conservadora, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - F Montagner
- Programa de Pós-graduação em Odontologia, Faculdade de Odontologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Curso de Odontologia, Universidade Regional Integrada do Alto Uruguai e das Missões, Erechim, Brazil
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Stroemel-Scheder C, Karmann AJ, Ziegler E, Heesen M, Knippenberg-Bigge K, Lang PM, Lautenbacher S. Sleep, Experimental Pain and Clinical Pain in Patients with Chronic Musculoskeletal Pain and Healthy Controls. J Pain Res 2019; 12:3381-3393. [PMID: 31908522 PMCID: PMC6930837 DOI: 10.2147/jpr.s211574] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 12/03/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose Everyday variations in night sleep in healthy pain-free subjects are at most weakly associated with pain, whereas strong alterations (eg, sleep deprivation, insomnia) lead to hyperalgesic pain changes. Since it remains unclear how substantial sleep alterations need to be in order to affect the pain system and lead to a coupling of both functions, the present study aimed at providing sufficient variance for co-variance analyses by examining a sample consisting of both healthy subjects and chronic pain patients. Methods A sample of 20 chronic musculoskeletal pain patients and 20 healthy controls was examined. This sample was assumed to show high inter-individual variability in sleep and pain, as pain patients frequently report sleep disturbances, whereas healthy subjects were required to be pain-free and normal sleepers. Sleep of two non-consecutive nights was measured using portable polysomnography and questionnaires. Experimental pain parameters (pressure pain thresholds (PPT), temporal summation of pain (TSP), conditioned pain modulation (CPM)) and situational pain catastrophizing (SCQ) were assessed in laboratory sessions before and after sleep. Pain patients’ clinical pain was assessed via questionnaire. Results As expected, both groups differed in several sleep parameters (reduced total sleep time and sleep efficiency, more time awake after sleep onset, lower subjective sleep quality in the patients) and in a few pain parameters (lower PPTs in the patients). In contrast, no differences were found in TSP, CPM, and SCQ. Contrary to our expectations, regression analyses indicated no prediction of overnight pain changes by sleep parameters. Conclusion Since sleep parameters were hardly apt to predict overnight pain changes, this leaves the association of both systems mainly unproven when using between-subject variance for verification.
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Affiliation(s)
| | | | | | - Michael Heesen
- Department of Anesthesiology and Pain Therapy, Kantonsspital Baden, Baden, Switzerland
| | | | - Philip M Lang
- Department of Anesthesiology and Pain Therapy, Sozialstiftung Bamberg, Bamberg, Germany
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Schanz M, Endres M, Löwe K, Lienig T, Deppert O, Lang PM, Varentsov D, Hoffmann DHH, Gutfleisch O. High energy proton induced radiation damage of rare earth permanent magnet quadrupoles. Rev Sci Instrum 2017; 88:125103. [PMID: 29289214 DOI: 10.1063/1.4997116] [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: 06/07/2023]
Abstract
Permanent magnet quadrupoles (PMQs) are an alternative to common electromagnetic quadrupoles especially for fixed rigidity beam transport scenarios at particle accelerators. Using those magnets for experimental setups can result in certain scenarios, in which a PMQ itself may be exposed to a large amount of primary and secondary particles with a broad energy spectrum, interacting with the magnetic material and affecting its magnetic properties. One specific scenario is proton microscopy, where a proton beam traverses an object and a collimator in which a part of the beam is scattered and deflected into PMQs used as part of a diagnostic system. During the commissioning of the PRIOR (Proton Microscope for Facility for Antiproton and Ion Research) high energy proton microscope facility prototype at Gesellschaft für Schwerionenforschung in 2014, a significant reduction of the image quality was observed which was partially attributed to the demagnetization of the used PMQ lenses and the corresponding decrease of the field quality. In order to study this phenomenon, Monte Carlo simulations were carried out and spare units manufactured from the same magnetic material-single wedges and a fully assembled PMQ module-were deliberately irradiated by a 3.6 GeV intense proton beam. The performed investigations have shown that in proton radiography applications the above described scattering may result in a high irradiation dose in the PMQ magnets. This did not only decrease the overall magnetic strength of the PMQs but also caused a significant degradation of the field quality of an assembled PMQ module by increasing the parasitic multipole field harmonics which effectively makes PMQs impractical for proton radiography applications or similar scenarios.
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Affiliation(s)
- M Schanz
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - M Endres
- Technische Universität Darmstadt, Darmstadt, Germany
| | - K Löwe
- Technische Universität Darmstadt, Darmstadt, Germany
| | - T Lienig
- Technische Universität Darmstadt, Darmstadt, Germany
| | - O Deppert
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - P M Lang
- Technische Universität Darmstadt, Darmstadt, Germany
| | - D Varentsov
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | | | - O Gutfleisch
- Technische Universität Darmstadt, Darmstadt, Germany
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Horn-Hofmann C, Wolf D, Wolff S, Heesen M, Knippenberg-Bigge K, Lang PM, Lautenbacher S. Startle modulation by heat pain with varying threat levels in chronic pain patients and pain-free controls. J Pain Res 2017; 10:1787-1800. [PMID: 28814894 PMCID: PMC5546785 DOI: 10.2147/jpr.s136416] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Empirical evidence suggests that affective responses to pain are changed in chronic pain. The investigation of startle responses to pain might contribute to clarifying whether such alterations also expand to motivational defensive reactions. We aimed at comparing startle responses to tonic heat pain with high threat (HT) or low threat (LT) in patients with chronic musculoskeletal pain and controls. As pain-related anxiety and catastrophizing are typically elevated in chronic pain, we expected to find stronger startle responses in patients specifically under experimental HT. Methods Patients with chronic musculoskeletal, preferentially, back pain (N = 19) and matched pain-free controls (N = 19) underwent two pain-related threat conditions (high and low) in balanced order. Only, in the HT condition, 50% of the trials were announced to include a short further noxious temperature increase at the end. Startle responses to loud tones were always assessed prior to a potential temperature increase in the phase of anticipation and were recorded by surface electromyogram. Results Surprisingly, we observed no differences in startle responses and ratings of emotional and pain responses between patients and controls despite significantly higher pain-related anxiety and catastrophizing in the patients. Overall, startle was potentiated in the HT condition, but only in participants who started with this condition. Conclusion Our results suggest that, in general, patients with pain are not more responsive emotionally to experimental threat manipulations despite elevated pain anxiety and catastrophizing. Instead, exaggerated responses in patients might be triggered only by individual concerns relating to pain, which are not sufficiently mirrored by our threat paradigm.
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Affiliation(s)
- C Horn-Hofmann
- Department of Physiological Psychology, University of Bamberg, Germany
| | - D Wolf
- Department of Physiological Psychology, University of Bamberg, Germany
| | - S Wolff
- Department of Physiological Psychology, University of Bamberg, Germany
| | - M Heesen
- Department of Anesthesiology and Pain Therapy, Kantonsspital Baden, Switzerland
| | - K Knippenberg-Bigge
- Department of Anesthesiology and Pain Therapy, Sozialstiftung Bamberg, Bamberg, Germany
| | - P M Lang
- Department of Anesthesiology and Pain Therapy, Sozialstiftung Bamberg, Bamberg, Germany
| | - S Lautenbacher
- Department of Physiological Psychology, University of Bamberg, Germany
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Varentsov D, Antonov O, Bakhmutova A, Barnes CW, Bogdanov A, Danly CR, Efimov S, Endres M, Fertman A, Golubev AA, Hoffmann DHH, Ionita B, Kantsyrev A, Krasik YE, Lang PM, Lomonosov I, Mariam FG, Markov N, Merrill FE, Mintsev VB, Nikolaev D, Panyushkin V, Rodionova M, Schanz M, Schoenberg K, Semennikov A, Shestov L, Skachkov VS, Turtikov V, Udrea S, Vasylyev O, Weyrich K, Wilde C, Zubareva A. Commissioning of the PRIOR proton microscope. Rev Sci Instrum 2016; 87:023303. [PMID: 26931841 DOI: 10.1063/1.4941685] [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: 06/05/2023]
Abstract
Recently, a new high energy proton microscopy facility PRIOR (Proton Microscope for FAIR Facility for Anti-proton and Ion Research) has been designed, constructed, and successfully commissioned at GSI Helmholtzzentrum für Schwerionenforschung (Darmstadt, Germany). As a result of the experiments with 3.5-4.5 GeV proton beams delivered by the heavy ion synchrotron SIS-18 of GSI, 30 μm spatial and 10 ns temporal resolutions of the proton microscope have been demonstrated. A new pulsed power setup for studying properties of matter under extremes has been developed for the dynamic commissioning of the PRIOR facility. This paper describes the PRIOR setup as well as the results of the first static and dynamic proton radiography experiments performed at GSI.
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Affiliation(s)
- D Varentsov
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - O Antonov
- Physics Department, Technion, Haifa, Israel
| | - A Bakhmutova
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - C W Barnes
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - A Bogdanov
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - C R Danly
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - S Efimov
- Physics Department, Technion, Haifa, Israel
| | - M Endres
- Technische Universität Darmstadt, Darmstadt, Germany
| | - A Fertman
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - A A Golubev
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | | | - B Ionita
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - A Kantsyrev
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | | | - P M Lang
- Technische Universität Darmstadt, Darmstadt, Germany
| | - I Lomonosov
- Institute of Problems of Chemical Physics, Chernogolovka, Russia
| | - F G Mariam
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - N Markov
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - F E Merrill
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - V B Mintsev
- Institute of Problems of Chemical Physics, Chernogolovka, Russia
| | - D Nikolaev
- Institute of Problems of Chemical Physics, Chernogolovka, Russia
| | - V Panyushkin
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - M Rodionova
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - M Schanz
- Technische Universität Darmstadt, Darmstadt, Germany
| | - K Schoenberg
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - A Semennikov
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - L Shestov
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - V S Skachkov
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - V Turtikov
- Institute for Theoretical and Experimental Physics, Moscow, Russia
| | - S Udrea
- Technische Universität Darmstadt, Darmstadt, Germany
| | - O Vasylyev
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - K Weyrich
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - C Wilde
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - A Zubareva
- Institute of Problems of Chemical Physics, Chernogolovka, Russia
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Prall M, Lang PM, LaTessa C, Mariam F, Merrill F, Shestov L, Simoniello P, Varentsov D, Durante M. Towards Proton Therapy and Radiography at FAIR. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1742-6596/599/1/012041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lang PM. [Painful ischemic neuropathy]. Nervenarzt 2015; 86:151-155. [PMID: 25620734 DOI: 10.1007/s00115-014-4125-4] [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] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chronic ischemia in patients with peripheral arterial disease (PAD) represents a common medical problem. Neuropathic changes and pain caused by chronic ischemia are often found in the lower extremities of these patients. Pain in patients with chronic critical limb ischemia fulfill the criteria of neuropathic pain. Diagnostic tools besides medical history and examination are questionnaires, quantitative sensory testing (QST) and measuring intraepidermal nerve fiber density (IENFD) when indicated. A pharmacological approach with non-opioids and opioids as well as antidepressive and anticonvulsive drugs (according to the recommendations for the therapy of neuropathic pain) seems to be indicated for treating painful ischemic neuropathy. Spinal cord stimulation (SCS) provides the best evidence for invasive procedures in treating chronic ischemic pain.
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Affiliation(s)
- P M Lang
- Klinik für Anaesthesiologie, Klinikum der Universität München, LMU Campus Großhadern, Marchioninistr. 15, 81377, München, Deutschland,
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Arik M, Aune S, Barth K, Belov A, Borghi S, Bräuninger H, Cantatore G, Carmona JM, Cetin SA, Collar JI, Da Riva E, Dafni T, Davenport M, Eleftheriadis C, Elias N, Fanourakis G, Ferrer-Ribas E, Friedrich P, Galán J, García JA, Gardikiotis A, Garza JG, Gazis EN, Geralis T, Georgiopoulou E, Giomataris I, Gninenko S, Gómez H, Gómez Marzoa M, Gruber E, Guthörl T, Hartmann R, Hauf S, Haug F, Hasinoff MD, Hoffmann DHH, Iguaz FJ, Irastorza IG, Jacoby J, Jakovčić K, Karuza M, Königsmann K, Kotthaus R, Krčmar M, Kuster M, Lakić B, Lang PM, Laurent JM, Liolios A, Ljubičić A, Luzón G, Neff S, Niinikoski T, Nordt A, Papaevangelou T, Pivovaroff MJ, Raffelt G, Riege H, Rodríguez A, Rosu M, Ruz J, Savvidis I, Shilon I, Silva PS, Solanki SK, Stewart L, Tomás A, Tsagri M, van Bibber K, Vafeiadis T, Villar J, Vogel JK, Yildiz SC, Zioutas K. Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap. Phys Rev Lett 2014; 112:091302. [PMID: 24655238 DOI: 10.1103/physrevlett.112.091302] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Indexed: 06/03/2023]
Abstract
The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the search range 0.64 eV ≲ ma ≲ 1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ ≲ 3.3 × 10(-10) GeV(-1) at 95% C.L., with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of gaγ, for example by the currently discussed next generation helioscope International AXion Observatory.
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Affiliation(s)
- M Arik
- Dogus University, Istanbul, Turkey
| | - S Aune
- IRFU, Centre d'Études Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France
| | - K Barth
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - A Belov
- Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow, Russia
| | - S Borghi
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - H Bräuninger
- Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany
| | - G Cantatore
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste and Università di Trieste, Trieste, Italy
| | - J M Carmona
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | | | - J I Collar
- Enrico Fermi Institute and KICP, University of Chicago, Chicago, Illinois 60637, Illinois, USA
| | - E Da Riva
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - T Dafni
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - M Davenport
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | | | - N Elias
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - G Fanourakis
- National Center for Scientific Research "Demokritos", Athens, Greece
| | - E Ferrer-Ribas
- IRFU, Centre d'Études Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France
| | - P Friedrich
- Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany
| | - J Galán
- IRFU, Centre d'Études Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France and Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - J A García
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - A Gardikiotis
- Physics Department, University of Patras, Patras, Greece
| | - J G Garza
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - E N Gazis
- National Technical University of Athens, Athens, Greece
| | - T Geralis
- National Center for Scientific Research "Demokritos", Athens, Greece
| | | | - I Giomataris
- IRFU, Centre d'Études Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France
| | - S Gninenko
- Institute for Nuclear Research (INR), Russian Academy of Sciences, Moscow, Russia
| | - H Gómez
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - M Gómez Marzoa
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - E Gruber
- Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - T Guthörl
- Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | | | - S Hauf
- Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - F Haug
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - M D Hasinoff
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - D H H Hoffmann
- Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - F J Iguaz
- IRFU, Centre d'Études Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France and Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - I G Irastorza
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - J Jacoby
- Johann Wolfgang Goethe-Universität, Institut für Angewandte Physik, Frankfurt am Main, Germany
| | - K Jakovčić
- Rudjer Bošković Institute, Zagreb, Croatia
| | - M Karuza
- Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste and Università di Trieste, Trieste, Italy
| | - K Königsmann
- Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - R Kotthaus
- Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany
| | - M Krčmar
- Rudjer Bošković Institute, Zagreb, Croatia
| | - M Kuster
- Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany and Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - B Lakić
- Rudjer Bošković Institute, Zagreb, Croatia
| | - P M Lang
- Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - J M Laurent
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - A Liolios
- Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - A Ljubičić
- Rudjer Bošković Institute, Zagreb, Croatia
| | - G Luzón
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - S Neff
- Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - T Niinikoski
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - A Nordt
- Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany and Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - T Papaevangelou
- IRFU, Centre d'Études Nucléaires de Saclay (CEA-Saclay), Gif-sur-Yvette, France
| | - M J Pivovaroff
- Lawrence Livermore National Laboratory, Livermore, California 94550, California, USA
| | - G Raffelt
- Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), München, Germany
| | - H Riege
- Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - A Rodríguez
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - M Rosu
- Technische Universität Darmstadt, IKP, Darmstadt, Germany
| | - J Ruz
- European Organization for Nuclear Research (CERN), Genève, Switzerland and Lawrence Livermore National Laboratory, Livermore, California 94550, California, USA
| | - I Savvidis
- Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - I Shilon
- European Organization for Nuclear Research (CERN), Genève, Switzerland and Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - P S Silva
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - S K Solanki
- Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany
| | - L Stewart
- European Organization for Nuclear Research (CERN), Genève, Switzerland
| | - A Tomás
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - M Tsagri
- European Organization for Nuclear Research (CERN), Genève, Switzerland and Physics Department, University of Patras, Patras, Greece
| | - K van Bibber
- Lawrence Livermore National Laboratory, Livermore, California 94550, California, USA
| | - T Vafeiadis
- European Organization for Nuclear Research (CERN), Genève, Switzerland and Aristotle University of Thessaloniki, Thessaloniki, Greece and Physics Department, University of Patras, Patras, Greece
| | - J Villar
- Grupo de Investigación de Física Nuclear y Astropartículas, Universidad de Zaragoza, Zaragoza, Spain
| | - J K Vogel
- Albert-Ludwigs-Universität Freiburg, Freiburg, Germany and Lawrence Livermore National Laboratory, Livermore, California 94550, California, USA
| | | | - K Zioutas
- European Organization for Nuclear Research (CERN), Genève, Switzerland and Physics Department, University of Patras, Patras, Greece
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Fleckenstein J, Sittl R, Averbeck B, Lang PM, Irnich D, Carr RW. Activation of axonal Kv7 channels in human peripheral nerve by flupirtine but not placebo - therapeutic potential for peripheral neuropathies: results of a randomised controlled trial. J Transl Med 2013; 11:34. [PMID: 23394517 PMCID: PMC3648471 DOI: 10.1186/1479-5876-11-34] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [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: 07/11/2012] [Accepted: 11/07/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Flupirtine is an analgesic with muscle-relaxing properties that activates Kv7 potassium channels. Kv7 channels are expressed along myelinated and unmyelinated peripheral axons where their activation is expected to reduce axonal excitability and potentially contribute to flupirtine's clinical profile. TRIAL DESIGN To investigate the electrical excitability of peripheral myelinated axons following orally administered flupirtine, in-vitro experiments on isolated peripheral nerve segments were combined with a randomised, double-blind, placebo-controlled, phase I clinical trial (RCT). METHODS Threshold tracking was used to assess the electrical excitability of myelinated axons in isolated segments of human sural nerve in vitro and motoneurones to abductor pollicis brevis (APB) in situ in healthy subjects. In addition, the effect of flupirtine on ectopic action potential generation in myelinated axons was examined using ischemia of the lower arm. RESULTS Flupirtine (3-30 μM) shortened the relative refractory period and increased post-conditioned superexcitability in human myelinated axons in vitro. Similarly, in healthy subjects the relative refractory period of motoneurones to APB was reduced 2 hours after oral flupirtine but not following placebo. Whether this effect was due to a direct action of flupirtine on peripheral axons or temperature could not be resolved. Flupirtine (200 mg p.o.) also reduced ectopic axonal activity induced by 10 minutes of lower arm ischemia. In particular, high frequency (ca. 200 Hz) components of EMG were reduced in the post-ischemic period. Finally, visual analogue scale ratings of sensations perceived during the post-ischemic period were reduced following flupirtine (200 mg p.o.). CONCLUSIONS Clinical doses of flupirtine reduce the excitability of peripheral myelinated axons. TRIAL REGISTRATION ClinicalTrials registration is NCT01450865.
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Meyer-Bender A, Kern A, Pollwein B, Crispin A, Lang PM. Incidence and predictors of immediate complications following perioperative non-obstetric epidural punctures. BMC Anesthesiol 2012; 12:31. [PMID: 23227938 PMCID: PMC3566923 DOI: 10.1186/1471-2253-12-31] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [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: 07/25/2012] [Accepted: 11/29/2012] [Indexed: 12/04/2022] Open
Abstract
Background Epidural Anesthesia (EA) is a well-established procedure. The aim of the present study was to evaluate the incidence of immediate complications following epidural puncture, such as sanguineous puncture, accidental dural perforation, unsuccessful catheter placement or insufficient analgesia and to identify patient and maneuver related risk factors. Methods A total of 7958 non-obstetrical EA were analyzed. The risk of each complication was calculated according to the preconditions and the level of puncture. For probabilistic evaluation we used a logistic regression model with forward selection. Results The risk of sanguineous puncture (n = 247, 3.1%) increases with both the patient’s age (P = 0.013) and the more caudal the approach (P < 0.01). Dural perforation (n = 123, 1.6%) was found to be influenced only by advanced age (P = 0.019). Unsuccessful catheter placement (n = 68, 0.94%) occurred more often in smaller individuals (P < 0.001) and at lower lumbar sites (P < 0.01). Amongst all cases with successful catheter placement a (partial) insufficient analgesia was found in 692 cases (8.8%). This risk of insufficient analgesia decreased with patient’s age (P <0 .01), being least likely for punctures of the lower thoracic spine (P < 0.001). Conclusions Compared to more cranial levels, EA of the lower spine is associated with an increased risk of sanguineous and unsuccessful puncture. Insufficient analgesia more often accompanies high thoracic and low lumbar approaches. The risk of a sanguineous puncture increases in elderly patients. Gender, weight and body mass index seem to have no influence on the investigated complications.
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Affiliation(s)
- Andreas Meyer-Bender
- Department of Anaesthesiology, University Hospital of Munich, Marchioninistr, 15, 81377, Munich, Germany.
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Kramer S, Zaps D, Kutz DF, Wiegele B, Kolb FP, Zimmer K, Lehmeyer L, Fleckenstein J, Becker U, Lang PM, Irnich D. Impact of Surgical Intervention and Postoperative Pain on Electrical Skin Resistance at Acupuncture Points: An Exploratory Study. Acupunct Med 2012; 30:120-6. [DOI: 10.1136/acupmed-2011-010118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Objectives One theory about acupuncture suggests that pathological processes can cause measurable changes in electrical skin resistance (ESR) at acupuncture points (APs). Although the theory has yet to be proven, ESR measurements (ESRMs) form a frequently used part of contemporary acupuncture. The aim of this study was to test the so-called ‘electrical responsiveness’ of APs in the setting of a defined operative trauma. Methods ESRMs (n=424) were performed at the APs and surrounding skin of GB34 and ST38 in 163 participants using an impedance meter array developed for the purpose of ESRMs. For each group the percentage of measurements with a significantly different ESR between the APs and the surrounding skin was calculated and compared with each other. Measurements of four groups were compared: healthy control subjects (n=30) and patients after ophthalmic (n=29), hip (n=42) and shoulder (n=30) surgery. The influence of postoperative pain intensity was also assessed. Results Group comparison showed no significant differences for ST38. The ESRMs at GB34 had a significantly higher percentage of measurements with an increased ESR after ophthalmic (23.2%) and hip (22.2%) surgery, but not after shoulder surgery (7.5%). Subgroup analysis showed that an increase in pain intensity tended to lead to a decrease in the number of APs with ESR changes. Conclusion These results suggest that reactive changes in ESR at APs might exist. Pain and alertness seem to have an impact on ESR at APs. However, the current data do not allow for conclusions to be drawn concerning the clinical use of ESRMs.
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Affiliation(s)
- Sybille Kramer
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
| | - Daniela Zaps
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
| | - Dieter F Kutz
- Department of Physiological Genomics, University of Munich, Institute of Physiology, Munich, Germany
| | - Bernhard Wiegele
- Department of Electrical Engineering, University of Applied Science, Augsburg, Germany
| | - Florian P Kolb
- Department of Physiological Genomics, University of Munich, Institute of Physiology, Munich, Germany
| | - Katrin Zimmer
- Department of Anaesthesiology, District General Hospital, St Johann i Tirol, Austria
| | - Lukas Lehmeyer
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
| | - Johannes Fleckenstein
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
| | - Ursula Becker
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
| | - Philip M Lang
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
| | - Dominik Irnich
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
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Fleckenstein J, Kramer S, Offenbächer M, Schober G, Plischke H, Siebeck M, Mussack T, Hatz R, Lehmeyer L, Lang PM, Heindl B, Conzen P, Irnich D. Etoricoxib--preemptive and postoperative analgesia (EPPA) in patients with laparotomy or thoracotomy--design and protocols. Trials 2010; 11:66. [PMID: 20504378 PMCID: PMC2890651 DOI: 10.1186/1745-6215-11-66] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 05/27/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND AND OBJECTIVE Our objective was to report on the design and essentials of the Etoricoxib protocol- Preemptive and Postoperative Analgesia (EPPA) Trial, investigating whether preemptive analgesia with cox-2 inhibitors is more efficacious than placebo in patients who receive either laparotomy or thoracotomy. DESIGN AND METHODS The study is a 2 x 2 factorial armed, double blinded, bicentric, randomised placebo-controlled trial comparing (a) etoricoxib and (b) placebo in a pre- and postoperative setting. The total observation period is 6 months. According to a power analysis, 120 patients scheduled for abdominal or thoracic surgery will randomly be allocated to either the preemptive or the postoperative treatment group. These two groups are each divided into two arms. Preemptive group patients receive etoricoxib prior to surgery and either etoricoxib again or placebo postoperatively. Postoperative group patients receive placebo prior to surgery and either placebo again or etoricoxib after surgery (2 x 2 factorial study design). The Main Outcome Measure is the cumulative use of morphine within the first 48 hours after surgery (measured by patient controlled analgesia PCA). Secondary outcome parameters include a broad range of tests including sensoric perception and genetic polymorphisms. DISCUSSION The results of this study will provide information on the analgesic effectiveness of etoricoxib in preemptive analgesia and will give hints on possible preventive effects of persistent pain. TRIAL REGISTRATION NCT00716833.
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Lang PM, Stoer J, Schober GM, Audette JF, Irnich D. Bilateral acupuncture analgesia observed by quantitative sensory testing in healthy volunteers. Anesth Analg 2010; 110:1448-56. [PMID: 20237044 DOI: 10.1213/ane.0b013e3181d3e7ef] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND There is evidence that acupuncture activates different spinal and supraspinal antinociceptive systems, but the specific modulatory effects on the sensory system have not been systematically investigated. In this study, we evaluated the immediate effects of different types of acupuncture on thermal, mechanical, and vibratory sensory thresholds. METHODS Twenty-four healthy volunteers (12 men and 12 women, mean age 33.1 years) received 3 different forms of acupuncture in a single-blinded crossover design; these included manual acupuncture, acupuncture with low-frequency electrical stimulation, and acupuncture with high-frequency electrical stimulation. The time between the interventions was 1 week. All forms of acupuncture were applied unilaterally in the leg at standard acupuncture points: spleen 6, spleen 9, stomach 36, and gallbladder 39. The effects of acupuncture were evaluated by systematic quantitative sensory testing (QST) immediately after each intervention. QST was performed on bilateral lower extremities, including thermal and mechanical perception and pain and vibratory thresholds. RESULTS The heat pain threshold was increased after manual acupuncture on the treated and untreated side compared with baseline. Low- and high-frequency electrostimulation led to a higher mechanical pain threshold on the treated side compared with baseline and manual acupuncture. The pressure pain threshold was increased by all forms of acupuncture on both sides, with individual changes from baseline ranging from 25% to 52%. CONCLUSIONS There were congruent changes on QST after 3 common acupuncture stimulation methods, with possible unilateral as well as bilateral effects.
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Affiliation(s)
- Philip M Lang
- Department of Anaesthesiology, Multidisciplinary Pain Center, University of Munich (LMU), Munich, Germany
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Fleckenstein J, Zaps D, Rüger LJ, Lehmeyer L, Freiberg F, Lang PM, Irnich D. Discrepancy between prevalence and perceived effectiveness of treatment methods in myofascial pain syndrome: results of a cross-sectional, nationwide survey. BMC Musculoskelet Disord 2010; 11:32. [PMID: 20149248 PMCID: PMC2836281 DOI: 10.1186/1471-2474-11-32] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 02/11/2010] [Indexed: 12/15/2022] Open
Abstract
Background Myofascial pain is a common dysfunction with a lifetime prevalence affecting up to 85% of the general population. Current guidelines for the management of myofascial pain are not available. In this study we investigated how physicians on the basis of prescription behaviour evaluate the effectiveness of treatment options in their management of myofascial pain. Methods We conducted a cross-sectional, nationwide survey with a standardized questionnaire among 332 physicians (79.8% male, 25.6% female, 47.5 ± 9.6 years) experienced in treating patients with myofascial pain. Recruitment of physicians took place at three German meetings of pain therapists, rheumatologists and orthopaedists, respectively. Physicians estimated the prevalence of myofascial pain amongst patients in their practices, stated what treatments they used routinely and then rated the perceived treatment effectiveness on a six-point scale (with 1 being excellent). Data are expressed as mean ± standard deviation. Results The estimated overall prevalence of active myofascial trigger points is 46.1 ± 27.4%. Frequently prescribed treatments are analgesics, mainly metamizol/paracetamol (91.6%), non-steroidal anti-inflammatory drugs/coxibs (87.0%) or weak opioids (81.8%), and physical therapies, mainly manual therapy (81.1%), TENS (72.9%) or acupuncture (60.2%). Overall effectiveness ratings for analgesics (2.9 ± 0.7) and physical therapies were moderate (2.5 ± 0.8). Effectiveness ratings of the various treatment options between specialities were widely variant. 54.3% of all physicians characterized the available treatment options as insufficient. Conclusions Myofascial pain was estimated a prevalent condition. Despite a variety of commonly prescribed treatments, the moderate effectiveness ratings and the frequent characterizations of the available treatments as insufficient suggest an urgent need for clinical research to establish evidence-based guidelines for the treatment of myofascial pain syndrome.
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Affiliation(s)
- Johannes Fleckenstein
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
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Freysoldt A, Fleckenstein J, Lang PM, Irnich D, Grafe P, Carr RW. Low concentrations of amitriptyline inhibit nicotinic receptors in unmyelinated axons of human peripheral nerve. Br J Pharmacol 2009; 158:797-805. [PMID: 19694730 DOI: 10.1111/j.1476-5381.2009.00347.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Amitriptyline is often prescribed as a first-line treatment for neuropathic pain but its precise mode of analgesic action remains uncertain. Amitriptyline is known to inhibit voltage-dependent ion channels and also to act as an antagonist at ligand-gated ion channels, such as nicotinic acetylcholine receptors (nAChRs). In the present study, we tested the effect of amitriptyline on nicotinic responses of unmyelinated axons in isolated segments of human peripheral nerve. In particular, a comparison was made between the concentrations of amitriptyline necessary for inhibition of nAChRs and those required for inhibition of the compound C-fibre action potential. EXPERIMENTAL APPROACH Isolated axon fascicles were prepared from short segments of human sural nerve, and multiple measures of axonal excitability were recorded using computer-controlled threshold tracking software. KEY RESULTS Amitriptyline (EC(50) 2.6 microM) reduced the nicotine-induced increase in C-fibre excitability but only slightly altered the amplitude and latency to onset of the compound action potential. In contrast, tetrodotoxin produced a clear reduction in the amplitude and a prolongation of action potential onset latency but was without effect on the nicotine-induced increase in axonal excitability. CONCLUSIONS AND IMPLICATIONS These data demonstrate that low concentrations of amitriptyline suppress the response of human peripheral C-type axons to nicotine by directly inhibiting nAChRs. Blockade of tetrodotoxin-sensitive, voltage-dependent sodium channels does not contribute to this effect. An inhibitory action of amitriptyline on nAChRs in unmyelinated nociceptive axons may be an important component of amitriptyline's therapeutic effect in the treatment of neuropathic pain.
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Affiliation(s)
- A Freysoldt
- Institute of Physiology, University of Munich, Munich, Germany
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Fleckenstein J, Kramer S, Hoffrogge P, Thoma S, Lang PM, Lehmeyer L, Schober GM, Pfab F, Ring J, Weisenseel P, Schotten KJ, Mansmann U, Irnich D. Acupuncture in acute herpes zoster pain therapy (ACUZoster) - design and protocol of a randomised controlled trial. BMC Complement Altern Med 2009; 9:31. [PMID: 19674449 PMCID: PMC2739152 DOI: 10.1186/1472-6882-9-31] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 08/12/2009] [Indexed: 11/29/2022]
Abstract
Background Acute herpes zoster is a prevalent condition. One of its major symptoms is pain, which can highly influence patient's quality of life. Pain therapy is limited. Acupuncture is supposed to soften neuropathic pain conditions and might therefore act as a therapeutic alternative. Objective of the present study is to investigate whether a 4 week semi-standardised acupuncture is non-inferior to sham laser acupuncture and the anticonvulsive drug gabapentine in the treatment of pain associated with herpes zoster. Methods/Design Three-armed, randomised, placebo-controlled trial with a total follow-up time of 6 months. Up to estimated 336 patients (interim analyses) with acute herpes zoster pain (VAS > 30 mm) will be randomised to one of three groups (a) semi-standardised acupuncture (168 patients); (b) gabapentine with individualised dosage between 900–3600 mg/d (84 patients); (c) sham laser acupuncture. Intervention takes place over 4 weeks, all patients will receive analgesic therapy (non-opioid analgesics: metamizol or paracetamol and opioids: tramadol or morphine). Therapy phase includes 4 weeks in which group (a) and (c) consist of 12 sessions per patient, (b) visits depend on patients needs. Main outcome measure is to assess the alteration of pain intensity before and 1 week after treatment sessions (visual analogue scale VAS 0–100 mm). Secondary outcome measure are: alteration of pain intensity and frequency of pain attacks; alteration of different aspects of pain evaluated by standardised pain questionnaires (NPI, PDI, SES); effects on quality of life (SF 36); analgesic demand; alteration of sensoric perception by systematic quantitative sensory testing (QST); incidence of postherpetic neuralgia; side effects and cost effectiveness. Credibility of treatments will be assessed. Discussion This study is the first large-scale randomised placebo controlled trial to evaluate the efficacy of acupuncture compared to gabapentine and sham treatment and will provide valuable new information about the clinical and physiological effects of acupuncture and gabapentine in the treatment of acute herpes zoster pain. The study has been pragmatically designed to ensure that the study findings can be implemented into clinical practice if acupuncture can be shown to be an effective treatment strategy in acute herpes zoster pain. Trial registration NCT00885586
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Kramer S, Winterhalter K, Schober G, Becker U, Wiegele B, Kutz DF, Kolb FP, Zaps D, Lang PM, Irnich D. Characteristics of electrical skin resistance at acupuncture points in healthy humans. J Altern Complement Med 2009; 15:495-500. [PMID: 19422323 DOI: 10.1089/acm.2008.0331] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES The aim of this study was to evaluate the phenomenon of electrical skin resistance (ESR) changes at different acupuncture points (APs). SETTING This single-blinded study was performed at the hospital of the University of Munich. DESIGN Six common APs were measured (TE5, PC6, LU6, ST36, SP6, GB39) in 53 subjects. Subgroups were formed with varying time intervals for follow-ups (1 minute, 1 hour, 1 week) and a varying grade of reduction of the stratum corneum. METHODS Electrical skin resistance measurements (ESRMs) were taken from a skin area of 6 x 6 cm using an array consisting of 64 (8 x 8) electrodes. The electrodes corresponding to the AP were located and the ESRM results were compared to those of the surrounding electrodes. The methodological setting made it possible to minimize major influence factors on electrical skin impedance measurements. RESULTS A total of 631 ESRMs was evaluated: In 62.8% of the measured APs, no significant ESR difference was found. In 234 (37.2%) of the ESRMs, the ESR at the AP was significantly different from the surrounding skin area, with 163 (25.9%) points showing a lower and 71 (11.3%) points showing a higher ESR. Reproducibility was extremely high after 1 minute but was low after 1 hour and 1 week. CONCLUSIONS This study shows that electrical skin resistance at APs can either be lower or higher compared to the surrounding area. The phenomenon is characterized by high short-term and low long-term reproducibility. Therefore, we conclude that APs might possess specific transient electrical properties. However, as the majority of the measured APs did not show a changed ESR, it cannot be concluded from our data that electrical skin resistance measurements can be used for acupuncture point localization or diagnostic/therapeutic purposes.
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Affiliation(s)
- Sybille Kramer
- Multidisciplinary Pain Centre, Department of Anaesthesiology, University of Munich, Munich, Germany
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18
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Lang PM, Vock G, Schober GM, Kramer S, Abahji T, Crispin A, Irnich D, Hoffmann U. Impact of endovascular intervention on pain and sensory thresholds in nondiabetic patients with intermittent claudication: a pilot study. J Pain 2008; 10:264-73. [PMID: 19010739 DOI: 10.1016/j.jpain.2008.09.001] [Citation(s) in RCA: 4] [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] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 08/11/2008] [Accepted: 09/08/2008] [Indexed: 12/14/2022]
Abstract
UNLABELLED Pain and sensory neuropathy are common in patients with peripheral arterial disease. So far it is unknown to what extent pain and sensory parameters can be ameliorated by endovascular intervention used to resolve the arterial obstruction. Seventeen nondiabetic patients with intermittent claudication were investigated in the present study. The patients had to undergo percutaneous transluminal angioplasty (PTA) to improve blood flow in the affected leg. To acquire detailed information of their sensory state quantitative sensory testing (QST) was performed before and 24 hours and 3 months after PTA. QST is a standardized clinical testing procedure for the detection of sensory changes that consists of multiple tests for thermal and mechanical detection and pain thresholds as well as vibratory thresholds and stimulus response functions. An age-matched control group was investigated with an interval of 3 months. Pain during exercise decreased by 60% (examined by numerical rating scale) after endovascular intervention, whereas the ankle/brachial-index-representing the peripheral hemodynamic situation-increased by 29%. Sensory function determined by QST did not change significantly following PTA over a 3-month period. Successfully performed PTA is highly effective in reducing exercise induced pain in patients with intermittent claudication. PERSPECTIVE The study demonstrates that successfully performed PTA is a highly effective tool in reducing exercise induced pain in patients with intermittent claudication. However, the pain reduction observed cannot be verified by evaluating sensory functions using standardized quantitative sensory testing.
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Affiliation(s)
- Philip M Lang
- Department of Anesthesiology, Interdisciplinary Pain Center, University of Munich, Germany.
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Abstract
BACKGROUND The intention of this study was to determine the status quo of commonly used pain therapies amongst treating physicians of different specialties and to examine their view on the problem of chronic ischemic pain. METHODS A total of 281 physicians treating patients with chronic ischemic pain were surveyed. The surveyed physicians were mainly specialists in the fields of surgery, pain therapy, and internal medicine. RESULTS Mainly a pharmacological therapy (metamizol/paracetamol, weak and strong opioids) was used in the treatment of chronic ischemic pain. We found differences between the specialties, for instance pain specialists used antidepressants and anticonvulsants more often than others. Therapeutic options were also evaluated differently by surgeons, pain therapists, and internal specialists: 57% of the surgeons considered the available symptomatic treatment options as sufficient whereas only 21% of the pain specialists agreed with that opinion. CONCLUSION The differences among the specialties and the fact that the majority of physicians characterized the available symptomatic treatment options as insufficient point towards a need to review the treatment of ischemic pain in an interdisciplinary approach.
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Affiliation(s)
- L J Rüger
- Interdisziplinäre Schmerzambulanz, Klinik für Anästhesiologie, Klinikum der Universität München, Ludwig-Maximilians-Universität München, Pettenkoferstrasse 8a, 80336, München, Germany
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Lang PM, Fleckenstein J, Passmore GM, Brown DA, Grafe P. Retigabine reduces the excitability of unmyelinated peripheral human axons. Neuropharmacology 2008; 54:1271-8. [PMID: 18474382 DOI: 10.1016/j.neuropharm.2008.04.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Revised: 04/10/2008] [Accepted: 04/11/2008] [Indexed: 01/03/2023]
Abstract
Enhancement of membrane K(+) conductance may reduce the abnormal excitability of primary afferent nociceptive neurons in neuropathic pain. It has been shown that retigabine, a novel anticonvulsant, activates Kv7 (KCNQ/M) channels in the axonal/nodal membrane of peripheral myelinated axons. In this study, we have tested the effects of retigabine on excitability parameters of C-type nerve fibers in isolated fascicles of human sural nerve. Application of retigabine (3-10 microM) produced an increase in membrane threshold. This effect was pronounced in depolarized axons and small in hyperpolarized axons. This finding indicates that retigabine produces a membrane hyperpolarization which is limited by the K(+) equilibrium potential. The retigabine-induced reduction in excitability was accompanied by modifications of the post-spike recovery cycle. Most notable is the development of a late subexcitability at 250-400 ms following a short burst of action potentials. All effects of retigabine were blocked in the presence of XE991 (10 microM). The data show that Kv7 channels are present on axons of unmyelinated, including nociceptive, peripheral human nerve fibers. It is likely that activation of these channels by retigabine may reduce the ectopic generation of action potentials in neuropathic pain.
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Affiliation(s)
- P M Lang
- Department of Physiology, University of Munich, Pettenkoferstrasse 12, D-80336 Munich, Germany
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Abstract
Treating ischemic pain is often unsatisfactory. Current findings demonstrate that patients with chronic ischemia may develop sensory neuropathy and signs of central sensitization. This issue makes is reasonable treating with conventional analgesics and drugs against neuropathic pain. Adenosine has also a pain reducing effect in neuropathic pain which makes it a possible therapeutic option in ischemic pain.We report of a patient with thromboangiitis obliterans. We treated his pain with a broad analgesic therapy and administered adenosine intravenously, which resulted in a reduction of pain for several hours. Afterwards the patient received buflomedil to increase adenosine plasma levels. A long term pain reduction could be achieved. Modulation of adenosine demonstrates an experimental approach in the therapy of ischemic pain in thromboangiitis obliterans.
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Affiliation(s)
- Philip M Lang
- Interdisziplinäre Schmerzambulanz, Klinik für Anästhesiologieder Ludwig-Maximilians-Universität München, Klinikum Innenstadt, München.
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Abstract
Recording of action potentials from single unmyelinated nerve fibers by microneurography is an important tool to investigate peripheral neural functions in human neuropathies. However, the interpretation of microneurography recordings can be difficult because axonal membrane potential is not revealed by this method. We tested the hypothesis that the recovery cycle of excitability after a single action potential is correlated with changes in the axonal membrane potential. To this end, we used the threshold tracking technique to study how different chemical mediators, with known effects on the membrane potential, influence the post-spike superexcitability of C-fiber compound action potentials in isolated rat sural and vagus nerves. We found that: (1) some chemical mediators (e.g., adenosine 5'-triphosphate) produce a reduction or loss of superexcitability together with increased axonal excitability, indicating membrane depolarization; (2) blockade of axonal hyperpolarization-activated (Ih) currents produces an enhancement of superexcitability together with a decreased excitability, indicating membrane hyperpolarization; and (3) application of calcium produces an increase in membrane threshold without an alteration in superexcitability, indicating a non-specific increase in surface charge and a change in the voltage-dependent activation of sodium channels. In addition, we demonstrated that membrane depolarization and hyperpolarization induce opposite post-spike latency shifts (changes in supernormality) in rat and human nerve segments. Thus, recordings of post-spike excitability and shifts in latency are sensitive techniques for detection of various types of neuromodulation, which are correlated with changes in membrane potential of unmyelinated peripheral axons and may help to understand observations obtained by microneurography in peripheral human neuropathies.
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Affiliation(s)
- Gila Moalem-Taylor
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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23
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Lang PM, Hilmer VB, Grafe P. Differential Contribution of Sodium Channel Subtypes to Action Potential Generation in Unmyelinated Human C-type Nerve Fibers. Anesthesiology 2007; 107:495-501. [PMID: 17721253 DOI: 10.1097/01.anes.0000278862.77981.c8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Background
Multiple voltage-dependent sodium channels (Na(v)) contribute to action potentials and excitability of primary nociceptive neurons. The aim of the current study was to characterize subtypes of Na(v) that contribute to action potential generation in peripheral unmyelinated human C-type nerve fibers.
Methods
Registration of C-fiber compound action potentials and determination of membrane threshold was performed by a computerized threshold tracking program. Nerve fibers were stimulated with a 1-ms current pulse either alone or after a small ramp current lasting 300 ms.
Results
Compound C-fiber action potentials elicited by supramaximal 1-ms current pulses were rather resistant to application of tetrodotoxin (30-90 nM). However, the same concentrations of tetrodotoxin strongly reduced the peak height and elevated membrane threshold of action potentials evoked at the end of a 300-ms current ramp. A similar effect was observed during application of lidocaine and mexiletine (50 microM each).
Conclusions
These data indicate that more than one type of Na(v) contributes to the generation of action potentials in unmyelinated human C-type nerve fibers. The peak height of an action potential produced by a short electrical impulse is dependent on the activation of tetrodotoxin-resistant ion channels. In contrast, membrane threshold and action potential peak height at the end of a slow membrane depolarization are regulated by a subtype of Na(v) with high sensitivity to low concentrations of tetrodotoxin, lidocaine, and mexiletine. The electrophysiologic and pharmacologic characteristics may indicate the functional activity of the Na(v) 1.7 subtype of voltage-dependent sodium channels.
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Affiliation(s)
- Philip M Lang
- Department of Anesthesiology, University of Munich, Munich, Germany.
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24
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Abstract
Vagal afferent neurons from the stomach may be activated not only by chemical stimuli in the mucosa but also by circulating factors. In the present study, we have used electrophysiological techniques to characterize functional activity of several receptors for chemical mediators on unmyelinated axons in isolated fascicles of human gastric vagus nerve. Application of agonists at the nicotinic acetylcholine receptor (nAChR), 5-HT(3) subtype of serotonin receptor, and the transient receptor potential vanilloid receptor-1 (TRPV1) resulted in a change in the height and/or threshold of the C-fiber compound action potential. These effects were blocked by specific antagonists of nAChR (mecamylamine), 5-HT(3) (Y-25130), and TRPV1 (capsazepine). We conclude that the chemosensitivity of unmyelinated vagal axons can be studied using isolated segments of human gastric vagus nerve. The presence of receptors indicates that circulating factors may modify vagal afferent neurons also by effects on the axonal membrane.
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MESH Headings
- Action Potentials/drug effects
- Action Potentials/physiology
- Aged
- Axons/drug effects
- Axons/physiology
- Capsaicin/pharmacology
- Cell Membrane/drug effects
- Cell Membrane/physiology
- Chemoreceptor Cells/drug effects
- Chemoreceptor Cells/physiology
- Female
- Gastric Mucosa/innervation
- Gastric Mucosa/physiology
- Humans
- Male
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Middle Aged
- Nerve Fibers, Unmyelinated/drug effects
- Nerve Fibers, Unmyelinated/physiology
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Nicotinic Agonists/pharmacology
- Nodose Ganglion/drug effects
- Nodose Ganglion/physiology
- Organ Culture Techniques
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/physiology
- Receptors, Serotonin, 5-HT3/drug effects
- Receptors, Serotonin, 5-HT3/physiology
- Serotonin Receptor Agonists/pharmacology
- TRPV Cation Channels/drug effects
- TRPV Cation Channels/physiology
- Vagus Nerve/drug effects
- Vagus Nerve/physiology
- Visceral Afferents/drug effects
- Visceral Afferents/physiology
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Affiliation(s)
- Philip M Lang
- Department of Anesthesiology, University of Munich, Germany.
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25
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Lang PM, Moalem-Taylor G, Tracey DJ, Bostock H, Grafe P. Activity-Dependent Modulation of Axonal Excitability in Unmyelinated Peripheral Rat Nerve Fibers by the 5-HT(3) Serotonin Receptor. J Neurophysiol 2006; 96:2963-71. [PMID: 16956988 DOI: 10.1152/jn.00716.2006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activity-dependent fluctuations in axonal excitability and changes in interspike intervals modify the conduction of trains of action potentials in unmyelinated peripheral nerve fibers. During inflammation of a nerve trunk, long stretches of axons are exposed to inflammatory mediators such as 5-hydroxytryptamine [5-HT]. In the present study, we have tested the effects of m-chlorophenylbiguanide (mCPBG), an agonist at the 5-HT(3) serotonin receptor, on activity- and potential-dependent variations in membrane threshold and conduction velocity of unmyelinated C-fiber axons of isolated rat sural nerve segments. The increase in axonal excitability during application of mCPBG was much stronger at higher frequencies of action potentials and/or during axonal membrane hyperpolarization. The effects on the postspike recovery cycle also depended on the rate of stimulation. At an action potential frequency of 1 Hz or in hyperpolarized axons, mCPBG produced a loss of superexcitability. In contrast, at 0.33 Hz, a small increase in the postspike subexcitability was observed. Similar effects on excitability changes were found when latency instead of threshold was recorded, but only at higher action potential frequencies: at 1.8 Hz, mCPBG increased conduction velocity and reduced postspike supernormality. The latter effect would increase the interspike interval if pairs of action potentials were conducted along several cm in an inflamed nerve trunk. These data indicate that activation of axonal 5-HT(3) receptors not only enhances membrane excitability but also modulates action potential trains in unmyelinated, including nociceptive, nerve fibers at high impulse rates.
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Affiliation(s)
- Philip M Lang
- Department of Physiology, University of Munich, Pettenkoferstrasse 12, D-80336 Munich, Germany
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26
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Lang PM, Schober GM, Rolke R, Wagner S, Hilge R, Offenbächer M, Treede RD, Hoffmann U, Irnich D. Sensory neuropathy and signs of central sensitization in patients with peripheral arterial disease. Pain 2006; 124:190-200. [PMID: 16716518 DOI: 10.1016/j.pain.2006.04.011] [Citation(s) in RCA: 53] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 03/22/2006] [Accepted: 04/10/2006] [Indexed: 12/14/2022]
Abstract
Patients with peripheral arterial disease (PAD) may develop a broad range of peripheral nerve dysfunctions including pain and sensory deficiencies due to chronic ischemia mostly involving the lower limbs. To investigate the degree of sensory abnormalities in such patients quantitative sensory testing (QST) might be a useful tool. Forty-five patients and 20 controls were enrolled in the present study and underwent QST according to the protocol of the German Research Network on Neuropathic Pain. PAD was graded according to the Rutherford classification. PAD patients were divided into two groups: 16 patients with critical limb ischemia (severe PAD) and 29 patients with intermittent claudication (moderate PAD). QST revealed impaired cold and warm detection, increased mechanical and vibration detection thresholds, and increased perceptual wind-up on the affected leg (all p<0.001). Paradoxical heat sensation (p<0.05) and dynamic mechanical allodynia (p<0.01) were also observed. Subgroup analysis of patients without diabetes (control n=20, moderate PAD n=21, severe PAD n=8) confirmed most of these findings. In patients with severe PAD, sensory deficits were more pronounced than in patients with moderate PAD and were detected even in the face. These data indicate that QST can detect sensory abnormalities in PAD patients. While the pattern of decreased perception suggests deafferentation for Abeta-, Adelta-, and C-fiber inputs, the presence of allodynia suggests that central sensitization also plays a role in the pain state of PAD patients. Subgroup analysis points towards a PAD-associated peripheral neuropathy independent of diabetes.
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Affiliation(s)
- Philip M Lang
- Department of Anesthesiology, University of Munich, Germany.
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27
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Abstract
The novel alpha-conotoxin Vc1.1 is a potential analgesic for the treatment of painful neuropathic conditions. In the present study, the effects of Vc1.1 were tested on the nicotine-induced increase in excitability of unmyelinated C-fiber axons in isolated segments of peripheral human nerves. Vc1.1 in concentrations above 0.1 microM antagonized the increase in axonal excitability produced by nicotine; the maximal inhibition was observed with 10 microM. We also demonstrate immunoreactivity for alpha 3 and alpha 5 subunits of neuronal nicotinic receptors on unmyelinated peripheral human axons. Blockade of nicotinic receptors on unmyelinated peripheral nerve fibers may be helpful in painful neuropathies affecting unmyelinated sympathetic and/or sensory axons.
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Affiliation(s)
- Philip M Lang
- Department of Anesthesiology, Ludwig-Maximilians University, 80336 Munich, Germany
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28
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Lang PM, Huge V, Mast G, Habler O. Survival of acute hemorrhage and extreme dilutional anemia in the presence of high-graded aortic valve stenosis. Acta Anaesthesiol Scand 2004; 48:521. [PMID: 15025619 DOI: 10.1111/j.1399-6576.2004.00358a.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lang PM, Burgstahler R, Sippel W, Irnich D, Schlotter-Weigel B, Grafe P. Characterization of neuronal nicotinic acetylcholine receptors in the membrane of unmyelinated human C-fiber axons by in vitro studies. J Neurophysiol 2003; 90:3295-303. [PMID: 12878715 DOI: 10.1152/jn.00512.2003] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Application of acetylcholine to peripheral nerve terminals in the skin is a widely used test in studies of human small-fiber functions. However, a detailed pharmacological profile and the subunit composition of nicotinic acetylcholine receptors in human C-fiber axons are not known. In the present study, we recorded acetylcholine-induced changes of the excitability and of the intracellular Ca2+ concentration in C-fiber axons of isolated human nerve segments. In addition, using immunohistochemistry, an antibody of a subtype of nicotinic acetylcholine receptor was tested. Acetylcholine and agonists reduced the current necessary for the generation of action potentials in C fibers by <or=30%. This increase in axonal excitability was accompanied by a rise in the free intracellular Ca2+ concentration. The following rank order of potency for agonists was found: epibatidine >> 5-Iodo-A-85380 > 1,1-dimethyl-4-phenylpiperazinium iodide > nicotine > cytisine > acetylcholine; choline had no effect. The epibatidine-induced increase in axonal excitability was blocked by mecamylamine and, less efficiently, by methyllycacontine and dihydro-beta-erythroidine. Many C-fiber axons were labeled by an antibody that recognizes the alpha5 subunit of nicotinic acetylcholine receptors. In summary, electrophysiological and immunohistochemical data indicate the functional expression of nicotinic acetylcholine receptors composed of alpha3, alpha5, and beta4 but not of alpha4/beta2 or of alpha7 subunits in the axonal membrane of unmyelinated human C fibers. In addition, the observations suggest that the axonal membrane of C fibers in isolated segments of human sural nerve can be used as a model for presumed cholinergic chemosensitivity of axonal terminals.
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Affiliation(s)
- P M Lang
- Departments of Physiology and Anesthesiology and Friedrich-Baur-Institute, Ludwig-Maximilians University, 80336 Munich, Germany
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30
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Affiliation(s)
- Philip M Lang
- Department of Anesthesiology, University of Munich, Germany.
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31
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Lang PM, Tracey DJ, Irnich D, Sippel W, Grafe P. Activation of adenosine and P2Y receptors by ATP in human peripheral nerve. Naunyn Schmiedebergs Arch Pharmacol 2002; 366:449-57. [PMID: 12382074 DOI: 10.1007/s00210-002-0624-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2002] [Accepted: 07/11/2002] [Indexed: 11/28/2022]
Abstract
Receptors for ATP in the peripheral nervous system may contribute to the transduction of sensory, including nociceptive, stimuli and are candidates in the pathogenesis of neuropathic pain. In a complex neural tissue, such as the human peripheral nerve trunk, ATP may activate P2X, P2Y, and adenosine receptors present on various cell types. Experiments were performed on segments of isolated human sural nerves. The experimental set-up enabled simultaneous recording of C fiber excitability, intracellular Ca(2+) ([Ca(2+)](i)) and extracellular K(+) activity (aK(e)). The increase in excitability of unmyelinated fibers seen during bath application of both ATP and adenosine was reversed to a reduction in axonal excitability in the presence of 4-(2-[7-amino-2-(2-furyl)[1,2,4]triazolol[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385), an antagonist of adenosine A2 receptors. The pharmacological profile of the axonal subexcitability indicates the presence and activation of adenosine A1 receptors. Intracellular Ca(2+) transients were observed during bath application of ATP but not of adenosine and were blocked by 2'-deoxy- N(6)-methyladenosine 3',5'-bisphosphate (MRS 2179), an antagonist at P2Y(1) receptors. K(+)-sensitive microelectrodes were used to search for a possible activation of P2X receptors by ATP. In isolated rat vagus nerve, activation of P2X receptors by alpha,beta-methylene-adenosine 5'-triphosphate (alpha,beta-meATP) and by diadenosine pentaphosphate (Ap5A) resulted in a rapid, transient rise in the extracellular K(+) activity. In contrast, in human nerve, application of P2X receptor agonists did not result in a detectable elevation of aK(e). The data suggest that ATP-induced changes in axonal excitability and of [Ca(2+)](i) result from activation of adenosine A2, A1 and P2Y nucleotide receptors in human nerve; a contribution of P2X receptors was not found with the methods used. It is suggested that antagonists of A2 receptors might suppress enhanced activity in human nociceptive afferent nerve fibers under conditions in which ATP and/or adenosine is released into the trunk of a human peripheral nerve.
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Affiliation(s)
- Philip M Lang
- Department of Anaesthesiology, University of Munich, Germany
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32
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Abstract
Measurements of carbon monoxide (CO) in air samples collected from 27 locations between 71 degrees N and 41 degrees S show that atmospheric levels of this gas have decreased worldwide over the past 2 to 5 years. During this period, CO decreased at nearly a constant rate in the high northern latitudes. In contrast, in the tropics an abrupt decrease occurred beginning at the end of 1991. In the Northern Hemisphere, CO decreased at a spatially and temporally averaged rate of 7.3 (+/-0.9) parts per billion per year (6.1 percent per year) from June 1990 to June 1993, whereas in the Southern Hemisphere, CO decreased 4.2 (+/-0.5) parts per billion per year (7.0 percent per year). This recent change is opposite a long-term trend of a 1 to 2 percent per year increase inferred from measurements made in the Northern Hemisphere during the past 30 years.
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