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Sample records for fibrillation integration einer

  1. Integration einer Volltextsuchmaschine in Meta-Akad

    OpenAIRE

    Tuchbreiter, Jochen

    2003-01-01

    Das Projekt Meta-Akad hat das Ziel, Lernenden und Lehrenden den möglichst einfachen, umfassenden und schnellen Zugriff auf Lehrmaterial zu ermöglichen. Dabei werden verschiedene, über die Aspekte einer reinen Internet- Suchmaschine hinausgehende Aspekte berücksichtigt: Neben dem Aufbau einer umfangreichen und repräsentativen Sammlung von Lerndokumenten sollen diese mittels bibliothekarischer Methoden erschlossen und mit umfangreichen Metadaten, wie beispielsweise einer inhaltlichen Einordnung...

  2. Integration of cardiac computed tomography into pulmonary vein isolation in patients with paroxysmal atrial fibrillation; Integration einer praeinterventionellen Computertomografie des Herzens in die therapeutische Pulmonalvenenisolation bei Patienten mit paroxysmalem Vorhofflimmern

    Energy Technology Data Exchange (ETDEWEB)

    Weber, T.F. [Abt. Radiologie, Deutsches Krebsforschungszentrum, Heidelberg (Germany); Klemm, H.; Willems, S. [Klinik und Poliklinik fuer Kardiologie und Angiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany); Koops, A.; Adam, G.; Begemann, P.G. [Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie, Universitaetsklinikum Hamburg-Eppendorf (Germany); Nagel, H.D. [Philips Medizin Systeme GmbH, Hamburg (Germany)

    2007-12-15

    Purpose: Detailed anatomic information of the left atrium is necessary for securely performing radiofrequency ablation of atrial fibrillation-triggering ectopies in the pulmonary vein ostia. In this study the impact of a preinterventionally acquired cardiac computed tomography (CT) on pulmonary vein isolation (PVI) was assessed. Materials and methods: Examinations of 54 patients with paroxysmal atrial fibrillation undergoing PVI were analyzed. In 27 patients a supplementary cardiac CT was obtained prior to PVI (CT group, 12 women, 15 men, 59.7 {+-} 9.9 years of age): 16 x 1.5 mm collimation, 0.2 pitch, 120 kV tube voltage, 400 effective mAs. The fluoroscopy time, effective dose and quantity of radiofrequency (RF) pulses of the following catheter ablation were compared to 27 patients undergoing stand-alone PVI (11 women, 16 men, 62.0 {+-} 9.9 years of age). Mann-Whitney tests served for statistical comparison. Results: CT datasets were successfully integrated into the ablation procedure of each patient in the CT group. The mean quantity of RF pulses was significantly lower in the CT group (22.1 {+-} 8.0 vs. 29.1 {+-} 11.9, p = 0.030), and a significant reduction of fluoroscopy time was found (41.8 {+-} 12.0 min vs. 51.2 {+-} 16.0 min, p = 0.005). Effective doses of the catheter ablation differed in an equivalent dimension but altogether not significantly (14.9 {+-} 10.0 mSv vs. 20.0 {+-} 16.0 mSv, p = 0.203). The mean additive effective dose of the cardiac CT was 85 {+-} 0.3 mSv. (orig.)

  3. Integrating new approaches to atrial fibrillation management

    DEFF Research Database (Denmark)

    Kotecha, Dipak; Breithardt, Günter; Camm, A John

    2018-01-01

    There are major challenges ahead for clinicians treating patients with atrial fibrillation (AF). The population with AF is expected to expand considerably and yet, apart from anticoagulation, therapies used in AF have not been shown to consistently impact on mortality or reduce adverse...... of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new...

  4. [Manfred Schneider. Lübeck im 12. und 13. Jahrhundert. Archäologische Befunde zur entstehung einer mittelalterlichen Grossstadt. In : Expansion - integration? Danish-Baltic Contacts 1147-1410] / Dennis Hortmuth

    Index Scriptorium Estoniae

    Hortmuth, Dennis

    2011-01-01

    Arvustus:Manfred Schneider. Lübeck im 12. und 13. Jahrhundert. Archäologische Befunde zur entstehung einer mittelalterlichen Grossstadt. In : Expansion - integration? Danish-Baltic Contacts 1147-1410 AD. (Vordingborg, 2009).

  5. Integrated production of nano-fibrillated cellulose and cellulosic biofuel (ethanol) by enzymatic fractionation of wood fibers

    Science.gov (United States)

    Junyong Zhu; Ronald Sabo; Xiaolin Luo

    2011-01-01

    This study demonstrates the feasibility of integrating the production of nano-fibrillated cellulose (NFC), a potentially highly valuable biomaterial, with sugar/biofuel (ethanol) from wood fibers. Commercial cellulase enzymes were used to fractionate the less recalcitrant amorphous cellulose from a bleached Kraft eucalyptus pulp, resulting in a highly crystalline and...

  6. Epicardial, Biatrial Ablation With Integrated Uni-bipolar Radiofrequency Technology in Stand-alone Persistent Atrial Fibrillation.

    Science.gov (United States)

    Rosati, Fabrizio; Muneretto, Claudio; Merati, Elisa; Polvani, Gianluca; Moltrasio, Massimo; Tondo, Claudio; Curnis, Antonio; Cerini, Manuel; Metras, Alexandre; Bisleri, Gianluigi

    Although minimally invasive approaches for surgical treatment of stand-alone atrial fibrillation have gained popularity for the past decade, ablation technology and extensive lesion sets play a major role in the achievement of a successful procedure, especially in presence of persistent and long-standing persistent atrial fibrillation. We evaluated clinical outcomes after totally endoscopic biatrial epicardial ablation of persistent atrial fibrillation with a novel integrated uni-bipolar radiofrequency device. Forty-nine (49) consecutive patients with stand-alone atrial fibrillation underwent right-sided monolateral thoracoscopic surgical ablation with a novel integrated uni-bipolar radiofrequency energy delivery and temperature-controlled technology. Atrial fibrillation was persistent in 13 (26.5%) of 49 and long-standing persistent in 36 (73.5%) of 49 patients. Mean ± SD age was 60.6 ± 10.3 years. Median duration of atrial fibrillation was 74 months. Mean ± SD left atrial diameter was 44.7 ± 4.0 mm. Epicardial en bloc isolation of all pulmonary veins (box lesion) and additional ablation of the right atrial free wall was successfully performed via minimally invasive approach without any intraoperative and postoperative major complications. Intraoperative entrance and exit block was achieved in 77.5% (38/49) and 91.8% (45/49) of patients, respectively. Mean ± SD ablation time was 16.3 ± 4.8 minutes. No intensive care unit stay was required. Postoperative sinus rhythm was achieved in 93.8% (30/32) patients, and no pacemaker implantation was required. At 13 months, 87.7% (43/49) of patients were in sinus rhythm; 71.4% (35/49) were free from antiarrhythmic drugs and 75.5% (37/49) from oral anticoagulation. Integrated uni-bipolar radiofrequency ablation technology showed to be effective for the surgical treatment of atrial fibrillation with a total endoscopic approach. A versapolar suction device with extensive right-left atrial lesion set may further improve

  7. Integration of cardiac computed tomography into pulmonary vein isolation in patients with paroxysmal atrial fibrillation

    International Nuclear Information System (INIS)

    Weber, T.F.; Klemm, H.; Willems, S.; Koops, A.; Adam, G.; Begemann, P.G.; Nagel, H.D.

    2007-01-01

    Purpose: Detailed anatomic information of the left atrium is necessary for securely performing radiofrequency ablation of atrial fibrillation-triggering ectopies in the pulmonary vein ostia. In this study the impact of a preinterventionally acquired cardiac computed tomography (CT) on pulmonary vein isolation (PVI) was assessed. Materials and methods: Examinations of 54 patients with paroxysmal atrial fibrillation undergoing PVI were analyzed. In 27 patients a supplementary cardiac CT was obtained prior to PVI (CT group, 12 women, 15 men, 59.7 ± 9.9 years of age): 16 x 1.5 mm collimation, 0.2 pitch, 120 kV tube voltage, 400 effective mAs. The fluoroscopy time, effective dose and quantity of radiofrequency (RF) pulses of the following catheter ablation were compared to 27 patients undergoing stand-alone PVI (11 women, 16 men, 62.0 ± 9.9 years of age). Mann-Whitney tests served for statistical comparison. Results: CT datasets were successfully integrated into the ablation procedure of each patient in the CT group. The mean quantity of RF pulses was significantly lower in the CT group (22.1 ± 8.0 vs. 29.1 ± 11.9, p = 0.030), and a significant reduction of fluoroscopy time was found (41.8 ± 12.0 min vs. 51.2 ± 16.0 min, p = 0.005). Effective doses of the catheter ablation differed in an equivalent dimension but altogether not significantly (14.9 ± 10.0 mSv vs. 20.0 ± 16.0 mSv, p = 0.203). The mean additive effective dose of the cardiac CT was 85 ± 0.3 mSv. (orig.)

  8. Architecture of a fully integrated communication infrastructure for the smart home; Architektur einer vollintegrierten Kommunikationsinfrastruktur fuer das Smart Home

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Falk-Moritz; Kays, Ruediger [TU Dortmund (Germany). Lehrstuhl fuer Kommunikationstechnik

    2012-07-01

    For some time, applications in the areas of home automation, ambient assisted living and e-health are discussed. These require reliable and energy-efficient communication solutions in the home environment. In addition, new concepts that go hand in hand with the concept of the smart grids need an access to devices within the home environment. In the realization of smart homes the diversity of market participants involved, the parallel existing business models, the application requirements and the available communication systems make special demands on the underlying network infrastructure. Different solutions should be able to communicate with each other and compatible. In addition, the user expects a simple operation and configuration as well as a long-term support of the products. In the best case, the user is confronted with a single, integrated network infrastructure. Instead of separate systems for reading out of smart meters for monitoring the solar system, for health monitoring and the settings of multimedia devices, the telephone system, or computer network, a fully integrated smart home communications infrastructure should come into operation. This smart home infrastructure should be free of unnecessary duplication of structures; all equipment should be taken into account with a communication interface. The authors of the contribution under consideration report on a possible architecture of such a network infrastructure. Different grades are identified. A protocol stack for different technologies and the linking of different network hierarchies are described.

  9. Mobile Health Technology for Atrial Fibrillation Management Integrating Decision Support, Education, and Patient Involvement: mAF App Trial.

    Science.gov (United States)

    Guo, Yutao; Chen, Yundai; Lane, Deirdre A; Liu, Lihong; Wang, Yutang; Lip, Gregory Y H

    2017-12-01

    Mobile Health technology for the management of patients with atrial fibrillation is unknown. The simple mobile AF (mAF) App was designed to incorporate clinical decision-support tools (CHA 2 DS 2 -VASc [Congestive heart failure, Hypertension, Age ≥75 years, Diabetes Mellitus, Prior Stroke or TIA, Vascular disease, Age 65-74 years, Sex category], HAS-BLED [Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile INR, Elderly, Drugs/alcohol concomitantly], SAMe-TT 2 R 2 [Sex, Age Mobile Health technology in patients with atrial fibrillation, demonstrating that the mAF App, integrating clinical decision support, education, and patient-involvement strategies, significantly improved knowledge, drug adherence, quality of life, and anticoagulation satisfaction. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Vorhersagbarkeit einer koronaren Herzkrankheit im Rahmen einer arbeitsmedizinischen Vorsorgeuntersuchung

    OpenAIRE

    Berghoff, Bent Elger

    2004-01-01

    Angesichts der hohen Prävalenz der koronaren Herzkrankheit in der Bundesrepublik Deutschland sollte deren frühe Erkennung wesentlicher Bestandteil einer arbeitsmedizinischen Vorsorgeuntersuchung sein. Dies sollte nicht nur zum Schutz des betroffenen Arbeitnehmers geschehen, sondern auch zum Schutz Dritter, die als Folge einer unerwarteten Manifestation gefährdet werden könnten. Mehrere Gesetze und Verordnungen schreiben daher verschiedene Anlässe vor, die eine spezielle arbeitsmedizinisch...

  11. Advantages of horizontal and vertical integration in process- and switch gear control; Vorteile einer horizontalen und vertikalen Integration in Prozess- und Schaltanlagenautomatisierung

    Energy Technology Data Exchange (ETDEWEB)

    Erning, Peter; Langlotz, Kati [ABB AG, Mannheim (Germany). Div. Energietechnik

    2010-07-01

    Higher operating efficiency in power generation is more and more in the focus. Traditional control systems are frequently confined to the vertical integration of process control. It is quite common to use separate SCADA systems for controlling electrical auxiliary systems. However, there exists an overlap between these domains: major loads though belonging to the process are operated by medium-voltage switch gear. Until now the necessary control interconnections required the installation of costly and inflexible marshalling racks. Integrated operation and diagnostics was difficult to implement. These disadvantages apply accordingly in case of implementation of the entire sub-station via direct wiring. State-of-the-art control systems connect these two worlds in one system by integration of sub-station automation using the open standard IEC 61850 which allows freedom of choice in equipment and full access to all sub-station data. (orig.)

  12. Integration of a browser based operator manual in the system environment of a process computer system; Integration eines browserbasierten Betriebshandbuchs in die Systemumgebung einer Prozessrechneranlage

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Andreas [Westinghouse Electric Germany GmbH (Germany); Erfle, Robert [DOSCO GmbH, Heidelberg (Germany); Feinkohl, Dirk [E.ON Kernkraft GmbH (Germany). Kernkraftwerk Unterweser

    2012-11-01

    The integration of a browser based operator manual in the system environment of a process computer system is an optimization of the operating procedure in the control room and a safety enhancement due to faster and error-free access to the manual contents. Several requirements by the authorities have to be fulfilled: the operating manual has to be available as hard copy, the format has to be true to original, protection against manipulation has to be provided, the manual content of the browser-based version and the hard copy have to identical, and the display presentation has to be consistent with ergonomic principals. The integration of the on-line manual in the surveillance process computer system provides the operator with the relevant comments to the surveillance signal. The described integration of the on-line manual is an optimization of the operator's everyday job with respect to ergonomics and safety (human performance).

  13. Integrating genetic, transcriptional, and functional analyses to identify 5 novel genes for atrial fibrillation

    DEFF Research Database (Denmark)

    Sinner, Moritz F; Tucker, Nathan R; Lunetta, Kathryn L

    2014-01-01

    BACKGROUND: Atrial fibrillation (AF) affects >30 million individuals worldwide and is associated with an increased risk of stroke, heart failure, and death. AF is highly heritable, yet the genetic basis for the arrhythmia remains incompletely understood. METHODS AND RESULTS: To identify new AF-re...

  14. Warfarin Management and Outcomes in Patients with Nonvalvular Atrial Fibrillation Within an Integrated Health Care System.

    Science.gov (United States)

    An, JaeJin; Niu, Fang; Zheng, Chengyi; Rashid, Nazia; Mendes, Robert A; Dills, Diana; Vo, Lien; Singh, Prianka; Bruno, Amanda; Lang, Daniel T; Le, Paul T; Jazdzewski, Kristin P; Aranda, Gustavus

    2017-06-01

    Warfarin is a common treatment option to manage patients with nonvalvular atrial fibrillation (NVAF) in clinical practice. Understanding current pharmacist-led anticoagulation clinic management patterns and associated outcomes is important for quality improvement; however, currently little evidence associating outcomes with management patterns exists. To (a) describe warfarin management patterns and (b) evaluate associations between warfarin treatment and clinical outcomes for patients with NVAF in an integrated health care system. A retrospective cohort study was conducted among NVAF patients with warfarin therapy between January 1, 2006, and December 31, 2011, using Kaiser Permanente Southern California data, and followed until December 31, 2013. Management patterns related to international normalized ratio (INR) monitoring, anticoagulation clinic pharmacist intervention (consultation), and warfarin dose adjustments were investigated along with yearly attrition rates, time-in-therapeutic ranges (TTRs), and clinical outcomes (stroke or systemic embolism and major bleeding). Descriptive statistics and multivariable Cox proportional hazard models were used to determine associations between TTR and clinical outcomes. A total of 32,074 NVAF patients on warfarin treatment were identified and followed for a median of 3.8 years. About half (49%) of the patients were newly initiating warfarin therapy. INR monitoring and pharmacist interventions were conducted roughly every 3 weeks after 6 months of warfarin treatment. Sixty-three percent of the study population had ≥ 1 warfarin dose adjustments with a mean (SD) of 6.7 (6.3) annual dose adjustments. Warfarin dose adjustments occurred at a median of 1 day (interquartile ranges [IQR] 1-3) after the INR measurement. Yearly attrition rate was from 3.3% to 6.3% during the follow-up, and median (IQR) TTR was 61% (46%-73%). Patients who received frequent INR monitoring (≥ 27 times per year), pharmacist interventions (≥ 24

  15. Rechtsgrundlagen einer Pflicht zur Einrichtung einer Compliance-Organisation

    OpenAIRE

    Meyer, Susanne; Fredrich, Jan

    2012-01-01

    Im deutschen Recht ist weiterhin nicht vollständig geklärt, ob und in welchem Umfang Unternehmen verpflichtet sind, eine Compliance Organisation einzurichten. Eine solche zeichnet sich dadurch aus, dass einer organisatorisch verselbständigten Einheit die zukunftsorientierte Sorge für das gesetzmäßige Verhalten aller Unternehmensangehörigen ebenso anvertraut ist wie die Umsetzung und Erstellung interner Richtlinien. In bestimmten Branchen, insbesondere der Finanzbranche, aber auch dort, wo nac...

  16. Waveform Integrity in Atrial Fibrillation: The Forgotten Issue of Cardiac Electrophysiology.

    Science.gov (United States)

    Martínez-Iniesta, Miguel; Ródenas, Juan; Alcaraz, Raúl; Rieta, José J

    2017-08-01

    Atrial fibrillation (AF) is the most common arrhythmia in clinical practice with an increasing prevalence of about 15% in the elderly. Despite other alternatives, catheter ablation is currently considered as the first-line therapy for the treatment of AF. This strategy relies on cardiac electrophysiology systems, which use intracardiac electrograms (EGM) as the basis to determine the cardiac structures contributing to sustain the arrhythmia. However, the noise-free acquisition of these recordings is impossible and they are often contaminated by different perturbations. Although suppression of nuisance signals without affecting the original EGM pattern is essential for any other later analysis, not much attention has been paid to this issue, being frequently considered as trivial. The present work introduces the first thorough study on the significant fallout that regular filtering, aimed at reducing acquisition noise, provokes on EGM pattern morphology. This approach has been compared with more refined denoising strategies. Performance has been assessed both in time and frequency by well established parameters for EGM characterization. The study comprised synthesized and real EGMs with unipolar and bipolar recordings. Results reported that regular filtering altered substantially atrial waveform morphology and was unable to remove moderate amounts of noise, thus turning time and spectral characterization of the EGM notably inaccurate. Methods based on Wavelet transform provided the highest ability to preserve EGM morphology with improvements between 20 and beyond 40%, to minimize dominant atrial frequency estimation error with up to 25% reduction, as well as to reduce huge levels of noise with up to 10 dB better reduction. Consequently, these algorithms are recommended as a replacement of regular filtering to avoid significant alterations in the EGMs. This could lead to more accurate and truthful analyses of atrial activity dynamics aimed at understanding and

  17. Welthafte Wirklichkeit in ihrer Begrundung in Gott: Versuch einer ...

    African Journals Online (AJOL)

    Welthafte Wirklichkeit in ihrer Begrundung in Gott: Versuch einer offenbarungstheologischen Neuinterpretation der Transzendentalienmetaphysik. Gottes Offenbarung in Jesus Christus als Ermoglichung des Vertrauens zu einer menschlichen Welt.

  18. Atrial fibrillation

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    Mean blood pressures were 126.03± ... optimal. Keywords: Atrial fibrillation, thrombosis, CHADS2 Score, stroke risk, hypertensive heart disease, ... general population and the average age group ... Appendix 1) to stratify the stroke risk and we.

  19. Atrial Fibrillation: Diagnosis

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Diagnosis Past Issues / Winter 2015 Table of Contents ... of your body's cells and organs. Read More "Atrial Fibrillation" Articles Atrial Fibrillation / Who Is at Risk for ...

  20. The effect of integrated cardiac rehabilitation versus treatment as usual for atrial fibrillation patients treated with ablation

    DEFF Research Database (Denmark)

    Risom, Signe Stelling; Zwisler, Ann-Dorth Olsen; Rasmussen, Trine Bernholdt

    2013-01-01

    fibrillation treated with ablation. METHODS AND ANALYSIS DESIGN: The trial is a multicentre parallel arm design with 1:1 randomisation to the intervention and control group with blinded outcome assessment. 210 patients treated for atrial fibrillation with radiofrequency ablation will be included...... measure is exercise capacity measured by the VO(2) peak. The secondary outcome measure is self-rated mental health measured by the Short Form 36 questionnaire. Postintervention, qualitative interviews will be conducted in 10% of the intervention group. ETHICS AND DISSEMINATION: The protocol is approved...

  1. Atrial fibrillation

    DEFF Research Database (Denmark)

    Olesen, Morten S; Nielsen, Morten W; Haunsø, Stig

    2014-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1-2% of the general population. A number of studies have demonstrated that AF, and in particular lone AF, has a substantial genetic component. Monogenic mutations in lone and familial AF, although rare, have been recognized...

  2. [Atrial fibrillation].

    Science.gov (United States)

    Spinar, J; Vítovec, J

    2003-09-01

    Atrial fibrilation is the most frequent arrhythmia, the occurrence increasing with age and associated diseases. The incidence at the age below 60 years is markedly lower than one per cent, whereas in persons above 80 years of age it exceeds six per cent. The occurrence in patients with heart failure is from 10% (NYHA II) up to 50% (NYHA IV). Atrial fibrillation is classified into that observed for the first time and permanent, respectively, while transient forms include paroxyzmal and persistent atrial fibrillation. The diagnosis is based on ECG recording, while echocardiography is most significant. The therapy includes two basic questions--anticoagulant or anti-aggregation treatment and the control of rhythm or frequency. The anticoagulant therapy should be introduced in all patients, where contraindications are not present, being necessary before every cardioversion, provided atrial fibrillation lasts more than two days. In patients without any heart disease and with a physiological echocardiogram it is possible to administer only anti-aggregation treatment. Cardioversion (the control of rhythm) is recommended to all symptomatic patients, in other cases and especially in older persons the control of frequency is safer and of more advantage. Electrical cardioversion is more effective that a pharmacological treatment, the sinus rhythm is preferably controlled by dofetilid, ibutilid, propafenon and amiodaron. For the control of heart rate beta-blockers, diltiazem, verapamil and digitalis are recommended.

  3. Atrial Fibrillation: Treatment

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Treatment Past Issues / Winter 2015 Table of Contents Treatment for atrial fibrillation depends on how often you have symptoms, how ...

  4. Atrial Fibrillation

    DEFF Research Database (Denmark)

    Staerk, Laila; Sherer, Jason A; Ko, Darae

    2017-01-01

    The past 3 decades have been characterized by an exponential growth in knowledge and advances in the clinical treatment of atrial fibrillation (AF). It is now known that AF genesis requires a vulnerable atrial substrate and that the formation and composition of this substrate may vary depending...... on comorbid conditions, genetics, sex, and other factors. Population-based studies have identified numerous factors that modify the atrial substrate and increase AF susceptibility. To date, genetic studies have reported 17 independent signals for AF at 14 genomic regions. Studies have established...

  5. Personalized management of atrial fibrillation

    DEFF Research Database (Denmark)

    Kirchhof, Paulus; Breithardt, Günter; Aliot, Etienne

    2013-01-01

    The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability......, and hospitalizations. During the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association (AFNET/EHRA) consensus conference, we identified the following opportunities to personalize management of AF in a better manner with a view to improve outcomes by integrating atrial morphology and damage...

  6. Atrial fibrillation or flutter

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000184.htm Atrial fibrillation or flutter To use the sharing features on this page, please enable JavaScript. Atrial fibrillation or flutter is a common type of abnormal ...

  7. Atrial fibrillation - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000237.htm Atrial fibrillation - discharge To use the sharing features on this ... have been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  8. Atrial Fibrillation - Multiple Languages

    Science.gov (United States)

    ... Are Here: Home → Multiple Languages → All Health Topics → Atrial Fibrillation URL of this page: https://medlineplus.gov/languages/ ... V W XYZ List of All Topics All Atrial Fibrillation - Multiple Languages To use the sharing features on ...

  9. Atrial Fibrillation: Complications

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Complications Past Issues / Winter 2015 Table of Contents ... has two major complications—stroke and heart failure. Atrial Fibrillation and Stroke Click to enlarge image This illustration ...

  10. Optimierung der Hupkraftverteilung eines airbagintegrierten Automobillenkrades mit Hilfe einer Parameterstudie

    OpenAIRE

    Pietsch, Karsten

    2011-01-01

    Die Hupkraftverteilung eines airbagintegrierten Automobillenkrades wird mit Hilfe einer Parameterstudie in MathCAD so optimiert, das an jeder Krafteinleitungsposition die Hupe mit einer geforderten Mindestkraft betätigt werden kann. Nach der Modellierung in MathCAD der zugehörigen Geometrie und der Dimensionierung der Federlagerung ist das zugehörige mechanische Ersatzmodell mit Hilfe einer Parameterstudie verändert worden, so dass die Hupkraftforderung erfüllt wird.

  11. Atrial fibrillation.

    Science.gov (United States)

    Bang, Casper N

    2013-10-01

    Atrial fibrillation (AF) is a common complication after myocardial infarction (MI) and new-onset AF has been demonstrated to be associated with adverse outcome and a large excess risk of death in both MI and aortic stenosis (AS) patients. Prevention of new-onset AF is therefore a potential therapeutic target in AS and MI patients. Lipid-lowering drugs, particularly statins, have anti-inflammatory and antioxidant properties that may prevent AF. Accordingly, statins are recommended as a class IIa recommendation for prevention of new-onset AF after coronary artery bypass grafting (CABG). However, this preventive effect has not been investigated on new-onset AF in asymptomatic patients with AS or a large scale first-time MI patient sample and data in patients not undergoing invasive cardiac interventions are limited. This PhD thesis was conducted at the Heart Centre, Rigshospitalet, Denmark, with the aim to investigate the three aforementioned questions and to add to the existing evidence of AF prevention with statins. This was done using three different settings: 1) a randomized patients sample of 1,873 from the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, 2) a register patient sample of 97,499 with first-time MI, and 3) all published studies until beginning of June 2011 examining statin treatment on new-onset and recurrent AF in patients not undergoing cardiac surgery. This thesis revealed that statins did not lower the incidence or the time to new-onset AF in patients with asymptomatic AS. However, statin treatment showed an independently preventive effect on new-onset AF, including type-dependent effect and a trend to dosage-dependent effect. In addition, this thesis showed that good compliance to statin treatment was important to prevent new-onset AF. Finally, the meta-analysis in this PhD thesis showed a preventive effect in the observational studies although this effect was absent in the randomized controlled trials. Based on this PhD thesis

  12. The impact of the CartoSound® image directly acquired from the left atrium for integration in atrial fibrillation ablation.

    Science.gov (United States)

    Kaseno, Kenichi; Hisazaki, Kaori; Nakamura, Kohki; Ikeda, Etsuko; Hasegawa, Kanae; Aoyama, Daisetsu; Shiomi, Yuichiro; Ikeda, Hiroyuki; Morishita, Tetsuji; Ishida, Kentaro; Amaya, Naoki; Uzui, Hiroyasu; Tada, Hiroshi

    2018-04-14

    Intracardiac echocardiographic (ICE) imaging might be useful for integrating three-dimensional computed tomographic (CT) images for left atrial (LA) catheter navigation during atrial fibrillation (AF) ablation. However, the optimal CT image integration method using ICE has not been established. This study included 52 AF patients who underwent successful circumferential pulmonary vein isolation (CPVI). In all patients, CT image integration was performed after the CPVI with the following two methods: (1) using ICE images of the LA derived from the right atrium and right ventricular outflow tract (RA-merge) and (2) using ICE images of the LA directly derived from the LA added to the image for the RA-merge (LA-merge). The accuracy of these two methods was assessed by the distances between the integrated CT image and ICE image (ICE-to-CT distance), and between the CT image and actual ablated sites for the CPVI (CT-to-ABL distance). The mean ICE-to-CT distance was comparable between the two methods (RA-merge = 1.6 ± 0.5 mm, LA-merge = 1.7 ± 0.4 mm; p = 0.33). However, the mean CT-to-ABL distance was shorter for the LA-merge (2.1 ± 0.6 mm) than RA-merge (2.5 ± 0.8 mm; p imaging, and whereas the greatest CT-to-ABL distance was observed at the roof portion of the left superior PV (3.7 ± 2.8 mm) after the RA-merge, it improved to 2.6 ± 1.9 mm after the LA-merge (p images of the LA directly acquired from the LA might lead to a greater accuracy of the CT image integration for the CVPI.

  13. Tratamento operatório da fibrilação atrial: revisão integrativa da literatura Surgical treatment of atrial fibrillation: integrative review

    Directory of Open Access Journals (Sweden)

    João Roberto Breda

    2011-09-01

    Full Text Available A fibrilação atrial (FA no pré-operatório de operações cardíacas abertas, incluindo revascularização cirúrgica do miocárdio (RCM e operações valvares, representa fator de risco independente para eventos cardíacos maiores e redução de sobrevida. Devido à complexidade do assunto, principalmente na avaliação das taxas de sucesso, foi proposta recentemente uma declaração de consenso pela International Society of Minimally Invasive Cardiothoracic Surgery (ISMICS, com o intuito de determinar se a ablação operatória da FA promove resultados clínicos favoráveis em pacientes submetidos a outras operações cardíacas na comparação com operações isoladas sem ablação. O objetivo deste trabalho é apresentar dados da literatura que possam contribuir para o consenso sobre o tratamento operatório da FA e ser utilizado como fonte de atualização. A metodologia envolveu revisão integrativa da literatura, com análise e síntese dos dados obtidos de forma descritiva, apresentando o conhecimento atual sobre o tema apresentadoWhen atrial fibrillation (AF is present in pre-operative open heart surgeries, including coronary artery bypass grafting and valve operations, it represents an independent risk factor for cardiac events and reduced survival. Due to the complexity of the subject, especially when evaluating success rates (reversion and maintenance of normal sinus rhythm, a consensus statement was recently proposed by the International Society of Minimally Invasive Cardiothoracic Surgery (ISMICS, in order to determine whether the intraoperative ablation of AF promotes favorable clinical outcomes in patients undergoing other cardiac operations in comparison with individual operations without ablation. The aim of this paper is to present published data which has contributed to consensus statement and can be useful as update source. The integrative review was the methodology that provides synthesis of knowledge and applicability

  14. To arrange the window - the creation of an integrated local view on information diversity / Das Fenster zur Information gestalten - die Schaffung einer integrierten lokalen Sicht auf die Vielfalt von Informationsressourcen

    Directory of Open Access Journals (Sweden)

    Nunnenmacher, Lothar

    2006-01-01

    Full Text Available The way our patrons search and use information resources has already changed substantially, but the shift to new technologies is not yet completed. Currently new information is mostly coming via "the screen", at least in the STM disciplines (science, technology, medicine. The challenge for libraries nowadays is, to arrange the window towards the bulk of available information according to the needs of different users. Several measures of integration are needed to achieve this aim: * Instead of supplying the information physically, we now have to provide quick access to different information systems, as far as possible integrated, and to enhance these systems with local enrichments (e.g. availability, local views or filters. * Beyond journal articles and books we have to integrate other media like photos, videos, or even scientific data. Moreover, the scientific and scholarly information is going to change the media format from paper to electronics, which we should take into consideration in our efforts. * We have to appreciate that library services are just a small contribution to the whole environment of learning, teaching or research at university. People should be served according to their needs with all resources in an integrated way instead of splitting them up into small partitions based on organisational units. To arrange the window means to integrate the necessary resources in a way that as much information as possible is included, but guidance and filtering tools avoid information overload. Based on a model to group information hierarchically a draft for an integrated “Search Centre” is presented.

  15. Cryoballoon Catheter Ablation in Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cevher Ozcan

    2011-01-01

    Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

  16. What Is Atrial Fibrillation?

    Science.gov (United States)

    ANSWERS by heart Cardiovascular Conditions What Is Atrial Fibrillation? Your heart has a natural pacemaker, called the “sinus node,” that makes electrical signals. These signals cause the heart to contract and pump ...

  17. Toward understanding insulin fibrillation.

    Science.gov (United States)

    Brange, J; Andersen, L; Laursen, E D; Meyn, G; Rasmussen, E

    1997-05-01

    Formation of insulin fibrils is a physical process by which partially unfolded insulin molecules interact with each other to form linear aggregates. Shielding of hydrophobic domains is the main driving force for this process, but formation of intermolecular beta-sheet may further stabilize the fibrillar structure. Conformational displacement of the B-chain C-terminal with exposure of nonpolar, aliphatic core residues, including A2, A3, B11, and B15, plays a crucial role in the fibrillation process. Recent crystal analyses and molecular modeling studies have suggested that when insulin fibrillates this exposed domain interacts with a hydrophobic surface domain formed by the aliphatic residues A13, B6, B14, B17, and B18, normally buried when three insulin dimers form a hexamer. In rabbit immunization experiments, insulin fibrils did not elicit an increased immune response with respect to formation of IgG insulin antibodies when compared with native insulin. In contrast, the IgE response increased with increasing content of insulin in fibrillar form. Strategies and practical approaches to prevent insulin from forming fibrils are reviewed. Stabilization of the insulin hexameric structure and blockage of hydrophobic interfaces by addition of surfactants are the most effective means of counteracting insulin fibrillation.

  18. Surgery for atrial fibrillation.

    Science.gov (United States)

    Viganò, M; Graffigna, A; Ressia, L; Minzioni, G; Pagani, F; Aiello, M; Gazzoli, F

    1996-01-01

    The mechanisms of atrial fibrillation arc multiple reentry circuits spinning around the atrial surface, and these baffle any attempt to direct surgical interruption. The purpose of this article is to report the surgical experience in the treatment of isolated and concomitant atrial fibrillation at the Cardiac Surgical Institute of the University of Pavia. In cases of atrial fibrillation secondary to mitral/valve disease, surgical isolation of the left atrium at the time of mitral valve surgery can prevent atrial fibrillation from involving the right atrium, which can exert its diastolic pump function on the right ventricle. Left atrial isolation was performed on 205 patients at the time of mitral valve surgery. Atrial partitioning ("maze operation") creates straight and blind atrial alleys so that non-recentry circuits can take place. Five patients underwent this procedure. In eight-cases of atrial fibrillation secondary to atrial septal defect, the adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation underwent surgical isolation of the right atrium associated which surgical correction of the defect, in order to let sinus rhythm govern the left atrium and the ventricles. "Lone" atrial fibrillation occurs in hearts with no detectable organic disease. Bi-atrial isolation with creation of an atrial septal internodal "corridor" was performed on 14 patients. In cases of atrial fibrillation secondary to mitral valve disease, left atrial isolation was performed on 205 patients at the time of mitral valve surgery with an overall sinus rhythm recovery of 44%. In the same period, sinus rhythm was recovered and persisted in only 19% of 252 patients who underwent mitral valve replacement along (P < 0.001). Sinus rhythm was less likely to recover in patients with right atriomegaly requiring tricuspid valve annuloplasty: 59% vs 84% (P < 0.001). Restoration of the right atrial function raised the cardiac index from 2.25 +/- 0.55 1/min per m2

  19. Ideen zu einer Literatursoziologie des Internets. Mit einer Blogotop-Analyse

    Directory of Open Access Journals (Sweden)

    Peer Trilcke

    2013-11-01

    Full Text Available Der Essay skizziert und exemplifiziert die Möglichkeiten einer Literatursoziologie des Internets und plädiert in diesem Zusammenhang für eine Empirisierung der Forschung zu diesem rasant wachsenden, jedoch bisher in seiner Differenziertheit allenfalls oberflächlich beschriebenen Feld der Kommunikation über Literatur. Hierzu werden die literaturwissenschaftlichen Internet Studies und ihr literatursoziologischer Teilbereich innerhalb der allgemeinen Digital Humanities verortet. Als Beispiel für eine in diesem Sinne relational-empirische Literatursoziologie des Internets werden erste Ergebnisse der Analyse eines sog. Bücherblogotops präsentiert, anhand derer sich einige Mechanismen der sekundären literarischen Kommunikation zwar nicht repräsentativ, aber doch exemplarisch diskutieren lassen.

  20. Atrial Fibrillation and Hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Jayaprasad N

    2005-10-01

    Full Text Available Atrial fibrillation occurs in 10 – 15% of patients with hyperthyroidism. Low serum thyrotropin concentration is an independent risk factor for atrial fibrillation. Thyroid hormone contributes to arrythmogenic activity by altering the electrophysiological characteristics of atrial myocytes by shortening the action potential duration, enhancing automaticity and triggered activity in the pulmonary vein cardio myocytes. Hyperthyroidism results in excess mortality from increased incidence of circulatory diseases and dysrhythmias. Incidence of cerebral embolism is more in hyperthyroid patients with atrial fibrillation, especially in the elderly and anti-coagulation is indicated in them. Treatment of hyperthyroidism results in conversion to sinus rhythm in up to two-third of patients. Beta-blockers reduce left ventricular hypertrophy and atrial and ventricular arrhythmias in patients with hyperthyroidism. Treatment of sub clinical hyperthyroidism is controversial. Optimizing dose of thyroxine treatment in those with replacement therapy and beta-blockers is useful in exogenous subclinical hyperthyroidism.

  1. Thyrotoxic atrial fibrillation.

    Science.gov (United States)

    Parmar, Malvinder S

    2005-01-04

    Atrial fibrillation is the most common cardiac complication of hyperthyroidism and occurs in 15% of patients with hyperthyroidism. It is associated with a higher risk of thromboembolism that often involves the central nervous system. Oral anticoagulation is important in the majority of these patients to prevent thromboembolic complications. These patients require adjustment in the dose of various rate-controlling agents because of increased clearance associated with hyperthyroidism and a decrease in warfarin dosage because of increased clearance of vitamin K-dependent clotting factors. The management of thyrotoxic atrial fibrillation is summarized in this clinical review.

  2. Beiträge zu einer kognitiv ausgerichteten Lexikographie

    African Journals Online (AJOL)

    rbr

    Jahrhunderten immer wieder abgelegte Bekenntnis zu dem Satz Sprache dient dem Ausdruck von Gedanken oder einer seiner Varianten zeigt, kognitive Orien- tierung ein altes Programm mit Sprache befaßter Disziplinen ist, hat sich eine. Linguistik, die dieses Programm wirklich auf ihre Fahnen geschrieben hat, erst.

  3. Beiträge zu einer kognitiv ausgerichteten lexikographie | Figge ...

    African Journals Online (AJOL)

    Nach einer "kognitiven Wende" in der Psychologie in der zweiten Hälfte der sechziger Jahre haben auch Teile der Linguistik und der Psycholinguistik begonnen, sich kognitiv zu orientieren. Hier wird ein Modell zugrunde gelegt, nach dem sprachliche Einheiten auf Einheiten des Gedächtnisses referieren. Einheiten des ...

  4. Anmerkungen zur Methode einer theologischen Wirtschafts- und Sozialethik

    OpenAIRE

    Mack, Elke

    2002-01-01

    "Moderne theologische Wirtschafts- und Sozialethik sollte im Rahmen der wissenschaftstheoretischen Schritte 'Analyse, Synthese, Operationalisierung' erfolgen. Die christliche Wirtschafts- und Sozialethik erfüllt bei diesem Zuschnitt den Anspruch einer modernen theologischen Gerechtigkeitstheorie, die erstens ihr hermeneutisches Vorverständnis hinreichend klärt und analytisch an Problemstellungen herangeht, die zweitens auf der Basis eines hypothetischen Konsenses aller Betroffener zu normativ...

  5. Modulation of atrial fibrillation

    NARCIS (Netherlands)

    Geuzebroek, G.S.C.

    2013-01-01

    In this thesis we investigate the results of various surgical procedures for atrial fibrillation which have been performed in the last 2 decades in the Sint Antonius Hospital, Nieuwegein, The Netherlands. In the 1990s the classical Maze III procedure was the main surgical technique for

  6. Screening for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Freedman, Ben; Camm, John; Calkins, Hugh

    2017-01-01

    Approximately 10% of ischemic strokes are associated with atrial fibrillation (AF) first diagnosed at the time of stroke. Detecting asymptomatic AF would provide an opportunity to prevent these strokes by instituting appropriate anticoagulation. The AF-SCREEN international collaboration was formed...

  7. HYPERTHYROIDISM AND ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    I. M. Marusenko

    2017-01-01

    Full Text Available Review on a problem of the development of atrial fibrillation in patients with thyrotoxicosis is presented. Thyrotoxicosis is one of the most frequent endocrine diseases, conceding only to a diabetes mellitus. The most frequent reasons of hyperthyroidism are Graves’ disease and functional thyroid autonomy. The authors give an analysis of data on the cardiac effects of thyrotoxicosis, features of heart remodeling under the influence of thyroid hyperfunction, prevalence of atrial fibrillation in thyrotoxicosis, depending on age, as well as the possibility of restoring sinus rhythm in the combination of these diseases. Particular attention is paid to the effect on the heart of subclinical thyrotoxicosis, which is defined as a dysfunction of the thyroid gland, characterized by low serum concentration of thyrotropin, normal values of free thyroxine and free triiodothyronine. Subclinical hyperthyroidism is also capable of causing heart remodeling and diastolic dysfunction.Prevalence of thyrotoxicosis in elderly people is higher in areas of iodine deficiency; it is relevant for our country due to the large territory of iodine deficiency. In elderly patients, the cardiac effects of thyrotoxicosis prevail in the clinical picture, that makes it difficult to diagnose endocrine disorders, and correction of thyrotoxicosis is critically important for the successful control of the heart rhythm. The article also discusses the problem of thyrotoxic cardiomyopathy, caused by the toxic effect of excess thyroid hormones: features of this heart disorder, factors affecting its formation, clinical significance and contribution to the development of rhythm disturbances. The greatest significance is the development of atrial fibrillation as a result of thyrotox-icosis in older patients who already have various cardiovascular diseases.Atrial fibrillation is the most frequent heart rhythm disorder in thyrotoxicosis. The main cause of arrhythmia in hyperthyroidism is the

  8. Informatische Modellbildung als Dimension einer künstlerisch-technisch konzipierten Medienbildung

    Directory of Open Access Journals (Sweden)

    Daniela Reimann

    2017-04-01

    Full Text Available Heute sind nicht nur diverse gestaltungsbezogene Disziplinen gefragt, sich aktiv mit der Digitalisierung von Information und ihren Potentialen und Nebenwirkungen für Bildungsprozesse auseinander zu setzen. In Deutschland haben sich Technikdidaktik und informatische Bildung getrennt von Medienpädagogik und Mediendidaktik entwickelt und wurden entsprechend unabhängig voneinander betrieben. Dies gilt auch für die Ästhetische Bildung, die informatisch-technische Inhalte kaum je curricular in die Auseinandersetzung mit digitaler Medienkultur integriert hat, schon gar nicht systematisch. Im diesem Artikel wird, ausgehend vom Stand der Forschung (zur Integration informatischer Inhalte in die Medienbildung und den identifizierten Grundproblemen der Medienbildung zwecks Kompensation der Defizite, ein auf Gestaltung basierter Ansatz präsentiert, kontextualisiert und diskutiert, der Technikverständnis in ein Konzept integrierter Medienbildung einbezieht, dies als Bildungsziel im Sinne eines ganzheitlichen Verständnisses von Welt begreift und daher disziplinüberschreitend angelegt ist. Der Ansatz geht über technokratische Vorstellungen einer Technikdidaktik hinaus, die Medientechnologien isoliert von lebensbedeutsamen, ästhetisch-künstlerisch gestalteten Kontexten betrachtet und vermittelt. Im didaktischen Konzept werden die Grundlagen informatischer Modellbildung als relevante Teilbereiche einer zeitgemässen, am Subjekt orientierten, gleichermassen ästhetisch-künstlerisch und technisch-informatisch geprägten Medienbildung aufgewiesen, ihre pädagogischen Vorläufer, Forschungsprojekte und Nachbardisziplinen benannt sowie Ausblicke für eine zeitgemässe Medienbildung gegeben.

  9. Genetics Home Reference: familial atrial fibrillation

    Science.gov (United States)

    ... Twitter Home Health Conditions Familial atrial fibrillation Familial atrial fibrillation Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Familial atrial fibrillation is an inherited abnormality of the heart's normal ...

  10. Die Zukunft des Sozialstaates Deutschland: Elemente einer Reformstrategie

    OpenAIRE

    Lampert, Heinz

    1998-01-01

    Die Notwendigkeit einer Reform des Sozialstaates Deutschland ist nach Auffassung des Autors evident, weil eine zu hohe Staats- und Sozialabgabenquote zu Steuervermeidung, Verringerung der Leistungsbereitschaft, Schwarzarbeit, Steuerhinterziehung, Korruption und Betrug führen und die Wettbewerbsfähigkeit der Wirtschaft gefährden. Der Sozialstaat, den der Verfasser als eine der großen Errungenschaften der Neuzeit interpretiert, kann nach seiner Überzeugung aber so reformiert werden, daß soziale...

  11. Kultur- und Nationalbewusstsein:zur Gestaltung einer nationalen Identität Madagaskars

    OpenAIRE

    Wallner, I. (Ingo)

    2013-01-01

    Die Zusammenführung der einzelnen madagassischen Gesellschaften zu einer „Prä-Nation“ fand 1896 durch die franz. Annexion Madagaskars ein Ende. Die Gesellschaften, in denen die Familie, ihre Ahnen, das Land der Ahnen sowie die kosmologischen Beziehungen den räumlich begrenzten identitären Horizont bildeten, instrumentalisierte die Kolonialmacht durch ihre politique des races. Ethnisierung wurde zum Instrument einer divide et impera-Politik. Das Ergebnis war der Abbruch einer Entwicklung zu na...

  12. [Atrial fibrillation in elderly].

    Science.gov (United States)

    Arquizan, Caroline

    2012-11-01

    Atrial fibrilation (AF) is frequent and a strong risk factor for ischemic stroke in elderly. Ischemic stroke in patients with AF are more severe. Vitamine K antagonist therapy is highly effective for stroke prevention but is associated with hemorrhagic risk. The new oral anticoagulants (direct thrombin inhibitor [dabigatran], and direct factor Xa inhibitors [rivaroxaban and apixaban]) have all shown non inferiority or superiority, with better safety, considering the risk of intracranial haemorrhage. On this basis, it is justified to give them in priority in the vast majority of patients with AF, the choice of the drug and the dose is individual.

  13. The effect of point mutations on structure and mechanical properties of collagen-like fibril: A molecular dynamics study

    International Nuclear Information System (INIS)

    Marlowe, Ashley E.; Singh, Abhishek; Yingling, Yaroslava G.

    2012-01-01

    Understanding sequence dependent mechanical and structural properties of collagen fibrils is important for the development of artificial biomaterials for medical and nanotechnological applications. Moreover, point mutations are behind many collagen associated diseases, including Osteogenesis Imperfecta (OI). We conducted a combination of classical and steered atomistic molecular dynamics simulations to examine the effect of point mutations on structure and mechanical properties of short collagen fibrils which include mutations of glycine to alanine, aspartic acid, cysteine, and serine or mutations of hydroxyproline to arginine, asparagine, glutamine, and lysine. We found that all mutations disrupt structure and reduce strength of the collagen fibrils, which may affect the hierarchical packing of the fibrils. The glycine mutations were more detrimental to mechanical strength of the fibrils (WT > Ala > Ser > Cys > Asp) than that of hydroxyproline (WT > Arg > Gln > Asn > Lys). The clinical outcome for glycine mutations agrees well with the trend in reduction of fibril's tensile strength predicted by our simulations. Overall, our results suggest that the reduction in mechanical properties of collagen fibrils may be used to predict the clinical outcome of mutations. Highlights: ► All mutations disrupt structure and bonding pattern and reduce strength of the collagen fibrils. ► Gly based mutations are worst to mechanical integrity of fibrils than that of Hyp. ► Lys and Arg mutations most dramatically destabilize collagen fibril properties. ► Clinical outcome of mutations may be related to the reduced mechanical properties of fibrils.

  14. The effect of point mutations on structure and mechanical properties of collagen-like fibril: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Marlowe, Ashley E.; Singh, Abhishek; Yingling, Yaroslava G., E-mail: yara_yingling@ncsu.edu

    2012-12-01

    Understanding sequence dependent mechanical and structural properties of collagen fibrils is important for the development of artificial biomaterials for medical and nanotechnological applications. Moreover, point mutations are behind many collagen associated diseases, including Osteogenesis Imperfecta (OI). We conducted a combination of classical and steered atomistic molecular dynamics simulations to examine the effect of point mutations on structure and mechanical properties of short collagen fibrils which include mutations of glycine to alanine, aspartic acid, cysteine, and serine or mutations of hydroxyproline to arginine, asparagine, glutamine, and lysine. We found that all mutations disrupt structure and reduce strength of the collagen fibrils, which may affect the hierarchical packing of the fibrils. The glycine mutations were more detrimental to mechanical strength of the fibrils (WT > Ala > Ser > Cys > Asp) than that of hydroxyproline (WT > Arg > Gln > Asn > Lys). The clinical outcome for glycine mutations agrees well with the trend in reduction of fibril's tensile strength predicted by our simulations. Overall, our results suggest that the reduction in mechanical properties of collagen fibrils may be used to predict the clinical outcome of mutations. Highlights: Black-Right-Pointing-Pointer All mutations disrupt structure and bonding pattern and reduce strength of the collagen fibrils. Black-Right-Pointing-Pointer Gly based mutations are worst to mechanical integrity of fibrils than that of Hyp. Black-Right-Pointing-Pointer Lys and Arg mutations most dramatically destabilize collagen fibril properties. Black-Right-Pointing-Pointer Clinical outcome of mutations may be related to the reduced mechanical properties of fibrils.

  15. Plattenepithelkarzinom in Verbindung mit einer roten Tätowierung.

    Science.gov (United States)

    Schmitz, Inge; Prymak, Oleg; Epple, Matthias; Ernert, Carsten; Tannapfel, Andrea

    2016-06-01

    Obwohl Tätowierungen in den letzten Jahren außerordentlich beliebt geworden sind, wurde in der Literatur bisher nur über wenige Fälle schwerer Reaktionen berichtet, die zu einer malignen Transformation führten. Dies steht im Kontrast zu der praktisch unüberschaubaren Zahl an Tätowierungen weltweit. Die Zusammensetzung der für Tätowierungen verwendeten Farbstoffe variiert stark, und selbst gleiche Farbtöne können unterschiedliche Komponenten enthalten. Das Ziel unserer Studie war es zu untersuchen, auf welche Weise Tätowierungen möglicherweise Hautkrebs auslösen können. Wir berichten über den seltenen Fall einer 24-jährigen Frau, bei der sich sieben Monate nachdem sie eine Tätowierung auf dem Fußrücken erhalten hatte in unmittelbarer Nähe des verwendeten roten Farbstoffs ein Plattenepithelkarzinom entwickelte. Die Komplikationen begannen mit einer unspezifischen Schwellung. Die Läsion wurde histologisch untersucht. Die Zusammensetzung des inkorporierten Farbstoffs wurde mittels Rasterelektronenmikroskopie in Kombination mit energiedispersiver Elementanalyse analysiert. Zur weiteren Charakterisierung wurden Thermogravimetrie und Pulverdiffraktometrie eingesetzt. Der Tätowierungsfarbstoff enthielt hauptsächlich Bariumsulfat; Spuren von Al, S, Ti, P, Mg und Cl ließen sich ebenfalls nachweisen. Bei der Analyse zeigten sich Pigmentgranula unterschiedlicher Größe. In seltenen Fällen kann Tätowierungstinte karzinogene Effekte haben, die multifaktoriell zu sein scheinen. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  16. Game-based Learning im Bildungskontext einer Hochschule. Ein Praxisbericht

    Directory of Open Access Journals (Sweden)

    Jochen Pfannstiel

    2009-04-01

    Full Text Available Das Fach Software-Engineering stellt Lernende und Lehrende gleichermassen vor eine grosse Herausforderung, da eine Vielzahl von abstrakten Methoden und Modellen zu erlernen sind. An der Hochschule Offenburg wurde das Lernspiel «Software Engineering in the Future» als Ergänzung zur Präsenzveranstaltung entwickelt. Die Studierenden sollen über das Lernspiel motiviert werden, sich mit der Thematik zu befassen, um dann in ansprechend gestalteten authentischen Szenarien einzelne Methoden zu erlernen und zu vertiefen. Der Artikel stellt die zentralen Aspekte der Spielentwicklung und Ergebnisse einer ersten Befragung der Studierenden vor.

  17. Hinderniserkennung und -verfolgung mit einer PMD-kamera im automobil

    Science.gov (United States)

    Schamm, Thomas; Vacek, Stefan; Natroshvilli, Koba; Marius Zöllner, J.; Dillmann, Rüdiger

    Die Detektion von Hindernissen vor dem Automobil ist eine Hauptanforderung an moderne Fahrerassistenzsysteme (FAS). In dieser Arbeit wird ein System vorgestellt, das mit Hilfe einer PMDKamera (Photomischdetektor) Hindernisse auf der Fahrspur erkennt und deren relevante Parameter bestimmt. Durch die PMD-Kamera werden zunächst 3D-Tiefenbilder der Fahrzeugumwelt generiert. Nach einem initialen Filterprozess werden im Tiefenbild mit Hilfe eines Bereichswachstumsverfahrens Hindernisse gesucht. Zur Stabilisierung des Verfahrens und zur Parameterberechnung wird ein Kaiman Filter eingesetzt. Das Ergebnis ist eine Liste aller Hindernisse im Fahrbereich des Automobils.

  18. Atrial fibrillation in the elderly

    Science.gov (United States)

    Franken, Roberto A.; Rosa, Ronaldo F.; Santos, Silvio CM

    2012-01-01

    This review discusses atrial fibrillation according to the guidelines of Brazilian Society of Cardiac Arrhythmias and the Brazilian Cardiogeriatrics Guidelines. We stress the thromboembolic burden of atrial fibrillation and discuss how to prevent it as well as the best way to conduct cases of atrial fibrillatios in the elderly, reverting the arrhythmia to sinus rhythm, or the option of heart rate control. The new methods to treat atrial fibrillation, such as radiofrequency ablation, new oral direct thrombin inhibitors and Xa factor inhibitors, as well as new antiarrhythmic drugs, are depicted. PMID:22916053

  19. Die Energiesicherheit Europas in Bezug auf Erdgas und die Auswirkungen einer Kartellbildung im Gassektor

    OpenAIRE

    Krämer, Luis-Martín

    2011-01-01

    Die Dissertation untersucht die aktuelle Sicherheit der europaeischen Erdgasversorgung. Sie beruecksichtigt zudem die moeglichen Auswirkungen einer Kartellbildung auf die europaeische Gasversorgungssicherheit. Die Arbeit besteht aus einer detaillierten empirischen Studie und darauf aufbauender Szenarioanalyse. Hierzu wird auf den Interdependenzansatz von Robert O. Keohane und Joseph Nye zurueckgegriffen. Zur Darstellung des komplexen Themenbereichs wird auf die Darstellungspraxis der Dichten ...

  20. Pharmacological Treatment for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Kaoru Sugi, MD PhD

    2005-01-01

    Full Text Available Pharmacological treatment for atrial fibrillation has a variety of purposes, such as pharmacological defibrillation, maintenance of sinus rhythm, heart rate control to prevent congestive heart failure and prevention of both cerebral infarction and atrial remodeling. Sodium channel blockers are superior to potassium channel blockers for atrial defibrillation, while both sodium and potassium channel blockers are effective in the maintenance of sinus rhythm. In general, digitalis or Ca antagonists are used to control heart rate during atrial fibrillation to prevent congestive heart failure, while amiodarone or bepridil also reduce heart rates during atrial fibrillation. Anticoagulant therapy with warfarin is recommended to prevent cerebral infarction and angiotensin converting enzyme antagonists or angiotensin II receptor blockers are also used to prevent atrial remodeling. One should select appropriate drugs for treatment of atrial fibrillation according to the patient's condition.

  1. Fracture mechanics of collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, Rene B; Mulder, Hindrik; Kovanen, Vuokko

    2013-01-01

    Tendons are important load-bearing structures, which are frequently injured in both sports and work. Type I collagen fibrils are the primary components of tendons and carry most of the mechanical loads experienced by the tissue, however, knowledge of how load is transmitted between and within...... fibrils is limited. The presence of covalent enzymatic cross-links between collagen molecules is an important factor that has been shown to influence mechanical behavior of the tendons. To improve our understanding of how molecular bonds translate into tendon mechanics, we used an atomic force microscopy...... technique to measure the mechanical behavior of individual collagen fibrils loaded to failure. Fibrils from human patellar tendons, rat-tail tendons (RTTs), NaBH₄ reduced RTTs, and tail tendons of Zucker diabetic fat rats were tested. We found a characteristic three-phase stress-strain behavior in the human...

  2. Cost-effectiveness of a specialized atrial fibrillation clinic vs. usual care in patients with atrial fibrillation

    NARCIS (Netherlands)

    Hendriks, Jeroen; Tomini, Florian; van Asselt, Thea; Crijns, Harry; Vrijhoef, Hubertus

    AIMS: A recent randomized controlled trial demonstrated significant reductions in cardiovascular hospitalizations and deaths with a nurse-led integrated chronic care approach in patients with atrial fibrillation (AF) compared with usual care. The aim of the present study is to assess

  3. Cost-effectiveness of a specialized atrial fibrillation clinic vs. usual care in patients with atrial fibrillation

    NARCIS (Netherlands)

    Hendriks, J.M.L.; Tomini, F.; van Asselt, A.D.I.; Crijns, H.J.G.M.; Vrijhoef, H.J.M.

    2013-01-01

    Aims A recent randomized controlled trial demonstrated significant reductions in cardiovascular hospitalizations and deaths with a nurse-led integrated chronic care approach in patients with atrial fibrillation (AF) compared with usual care. The aim of the present study is to assess

  4. Atrial fibrillation and hyperthyroidism: A literature review.

    Science.gov (United States)

    Reddy, Vivek; Taha, Wael; Kundumadam, Shanker; Khan, Mazhar

    Atrial fibrillation is the most common arrhythmia worldwide with increasing frequency noted with age. Hyperthyroidism is a well-known cause of atrial fibrillation with a 16%-60% prevalence of atrial fibrillation in patients with known hyperthyroidism Ross et al. (2016). While hyperthyroidism as a causative factor of atrial fibrillation is well established, this literature review aims to answer several questions on this topic including: 1. The relationship of atrial fibrillation to hyperthyroidism 2. Atrial fibrillation as a predictor of hyperthyroidism 3. The pathophysiology of thyrotoxic atrial fibrillation 4. Subclinical hyperthyroidism and the relationship with atrial fibrillation 5. Cardioversion and Catheter ablation of hyperthyroid patients with atrial fibrillation 6. Thrombotic risk of hyperthyroid patients with atrial fibrillation 7. Management of Thyrotoxic Atrial fibrillation 8. Pharmacological rhythm control in patients with hyperthyroidism and atrial fibrillation 9. Treatment of Hyperthyroidism to prevent atrial fibrillation 10. Clinical Implications of Hyperthyroidism and Atrial Fibrillation. Copyright © 2017 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  5. Transmission electron microscopy of amyloid fibrils.

    Science.gov (United States)

    Gras, Sally L; Waddington, Lynne J; Goldie, Kenneth N

    2011-01-01

    Transmission Electron Microscopy of negatively stained and cryo-prepared specimens allows amyloid fibrils to be visualised at high resolution in a dried or a hydrated state, and is an essential method for characterising the morphology of fibrils and pre-fibrillar species. We outline the key steps involved in the preparation and observation of samples using negative staining and cryo-electron preservation. We also discuss methods to measure fibril characteristics, such as fibril width, from electron micrographs.

  6. ASS-induzierte Asthmaanfälle nach ASS-Desaktivierung - Fallbericht einer seltenen Komplikation

    OpenAIRE

    Doktorowski, S; Creutz, P; Förster-Ruhrmann, U; Olze, H

    2015-01-01

    Einleitung: Patienten mit einer nasalen Polyposis (NP), einem Asthma und einer ASS-Intoleranz sind häufig durch schwere Krankheitsverläufe gekennzeichnet. Die ASS-Desaktivierung ist eine Therapieoption mit günstigen Effekten auf rhinitische und pulmonale Beschwerden.Methoden: Vorstellung eines ungewöhnlichen Verlaufs eines Patienten nach ASS-Desaktivierung. Ergebnisse: Ein männlicher 34-jähriger Patient mit einer ASS-Trias (NP-Grad 2., FEV-1 94,7%, Ø Peakflow 470 l/Min) erhielt stationär p...

  7. Cryoballoon Ablation for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Jason G. Andrade, MD

    2012-03-01

    Full Text Available Focal point-by-point radiofrequency catheter ablation has shown considerable success in the treatment of paroxysmal atrial fibrillation. However, it is not without limitations. Recent clinical and preclinical studies have demonstrated that cryothermal ablation using a balloon catheter (Artic Front©, Medtronic CryoCath LP provides an effective alternative strategy to treating atrial fibrillation. The objective of this article is to review efficacy and safety data surrounding cryoballoon ablation for paroxysmal and persistent atrial fibrillation. In addition, a practical step-by-step approach to cryoballoon ablation is presented, while highlighting relevant literature regarding: 1 the rationale for adjunctive imaging, 2 selection of an appropriate cryoballoon size, 3 predictors of efficacy, 4 advanced trouble-shooting techniques, and 5 strategies to reduce procedural complications, such as phrenic nerve palsy.

  8. Design of a modular cogeneration plant to supply residential buildings; Dimensionierung eines Blockheizkraftwerkes zur Versorgung einer Wohnsiedlung

    Energy Technology Data Exchange (ETDEWEB)

    Marquardt, R.

    2000-03-01

    Excel tables are presented for fast integral calculation of all energetic and monetary parameters required for calculating the economic efficiency of a cogeneration plant. The Excel programming is more detailed than the method of calculation specified in VDI 2067 in that it also provides potential energy savings,carbon dioxide reduction and exergetic calculations. Influencing parameters like technical data, energy consumption data, fuel properties, and the cost structure of electricity and heat supply can be freely chosen so as to enable maximum parameter variation and an analysis of their influence on the result. [German] Mit der vorliegenden Arbeit wurde ein Instrument in Form von Excel-Tabellen erstellt, das eine schnelle integrale Berechnung aller energetischen und monetaeren Ergebnisgroessen ermoeglicht, die beim Einsatz eines BHKW zur Versorgung einer Bedarfsstruktur im Vergleich zu einer konventionellen getrennten Energiebereitstellung von Interesse sind. Die Excel-Programmierung geht dabei ueber die Abbildung des in der VDI 2067 beschriebenen Berechnungsverfahrens hinaus und liefert neben der Berechnung der Waermebereitstellungskosten auch die Ermittlung von Energieeinspar-, CO{sub 2}-Minderungspotentialen sowie eine exergetische Betrachtung der Ergebnisse. Alle auf das Ergebnis einwirkende Parameter wie technische Anlagendaten, Energiebedarfswerte, Brennstoffeigenschaften, Kostenstruktur der Elektrizitaets- und Waermeversorgung u.a. sind prinzipiell frei waehlbar. So wurde sichergestellt, dass eine Variation verschiedener Parameter moeglich ist und deren Einfluss auf das Ergebnis analysiert werden kann. (orig.)

  9. Pack also the sauna. Integration of electricity storage; Auch die Sauna mit rein. Einbindung von Stromspeichern

    Energy Technology Data Exchange (ETDEWEB)

    Ullrich, Sven

    2013-10-01

    The installers have to handle with a variety of variables and options to plan and integrate the correct personal use system of solar power systems for their customers. [German] Die Installateure muessen mit einer Vielzahl von Variablen und Varianten zurechtkommen, um das richtige Eigenverbrauchssystem einer Solarstromanlage fuer ihre Kunden zu planen und einzubauen.

  10. Die Entstehung einer Nachbarsegmentdekompensation nach lumbaler Spondylodese. Einfluß des sagitalen Profils

    OpenAIRE

    Noe, Stephan

    2003-01-01

    Die vorliegende Arbeit beschäftigt sich mit der Frage, ob ein Zusammenhang zwischen der frühen Dekompensation einer Nachbaretage neben einem fusioniertem Bandscheibensegment im Lendenwirbelsäulenbereich und dem sagittalen Profil der Lendenwirbelsäule besteht. Im Rahmen der Untersuchungen wurden in einer retrospektiven Untersuchung die Krankenakten und Röntgenbilder von 51 Patienten der Zentralkliniken Bad Berka (Wirbelsäulenchirurgie) und Patienten der Orthopädischen Klinik des Universitä...

  11. Der Ritter mit dem Hemd : drei Fassungen einer mittelalterlichen Erzählung

    OpenAIRE

    Dunphy, Graeme

    2011-01-01

    Unter den zahlreichen Motiven, die in der mittelalterlichen Literatur mit Frauendienst verbunden sind, gehört das vom Ritter mit dem Hemd zu den besonders interessanten. Es erscheint zunächst in dem ersten von fünf Fabliaux aus einer verlorenen Turiner Handschrift, die dem sonst unbekannten altfranzösischen Dichter Jacques de Baisieux zugeschrieben werden, einer heiteren Kurzgeschichte mit dem Titel "Des trois chevaliers et del chainse". In der vorliegenden Untersuchung gilt es, der Frage der...

  12. Atrial fibrillation and delayed gastric emptying.

    Directory of Open Access Journals (Sweden)

    Isadora C Botwinick

    Full Text Available BACKGROUND: Atrial fibrillation and delayed gastric emptying (DGE are common after pancreaticoduodenectomy. Our aim was to investigate a potential relationship between atrial fibrillation and DGE, which we defined as failure to tolerate a regular diet by the 7(th postoperative day. METHODS: We performed a retrospective chart review of 249 patients who underwent pancreaticoduodenectomy at our institution between 2000 and 2009. Data was analyzed with Fisher exact test for categorical variables and Mann-Whitney U or unpaired T-test for continuous variables. RESULTS: Approximately 5% of the 249 patients included in the analysis experienced at least one episode of postoperative atrial fibrillation. Median age of patients with atrial fibrillation was 74 years, compared with 66 years in patients without atrial fibrillation (p = 0.0005. Patients with atrial fibrillation were more likely to have a history of atrial fibrillation (p = 0.03. 92% of the patients with atrial fibrillation suffered from DGE, compared to 46% of patients without atrial fibrillation (p = 0.0007. This association held true when controlling for age. CONCLUSION: Patients with postoperative atrial fibrillation are more likely to experience delayed gastric emptying. Interventions to manage delayed gastric function might be prudent in patients at high risk for postoperative atrial fibrillation.

  13. Nanomechanical properties of single amyloid fibrils

    International Nuclear Information System (INIS)

    Sweers, K K M; Bennink, M L; Subramaniam, V

    2012-01-01

    Amyloid fibrils are traditionally associated with neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease or Creutzfeldt-Jakob disease. However, the ability to form amyloid fibrils appears to be a more generic property of proteins. While disease-related, or pathological, amyloid fibrils are relevant for understanding the pathology and course of the disease, functional amyloids are involved, for example, in the exceptionally strong adhesive properties of natural adhesives. Amyloid fibrils are thus becoming increasingly interesting as versatile nanobiomaterials for applications in biotechnology. In the last decade a number of studies have reported on the intriguing mechanical characteristics of amyloid fibrils. In most of these studies atomic force microscopy (AFM) and atomic force spectroscopy play a central role. AFM techniques make it possible to probe, at nanometer length scales, and with exquisite control over the applied forces, biological samples in different environmental conditions. In this review we describe the different AFM techniques used for probing mechanical properties of single amyloid fibrils on the nanoscale. An overview is given of the existing mechanical studies on amyloid. We discuss the difficulties encountered with respect to the small fibril sizes and polymorphic behavior of amyloid fibrils. In particular, the different conformational packing of monomers within the fibrils leads to a heterogeneity in mechanical properties. We conclude with a brief outlook on how our knowledge of these mechanical properties of the amyloid fibrils can be exploited in the construction of nanomaterials from amyloid fibrils. (topical review)

  14. Stroke prevention in atrial fibrillation

    DEFF Research Database (Denmark)

    Fanaroff, Alexander C; Steffel, Jan; Alexander, John H

    2018-01-01

    of anticoagulation for atrial fibrillation (AF). Observational studies employing RWD are useful for describing how oral anticoagulants are used in clinical practice, but generally cannot be used to make claims regarding comparative treatment effects. Questions regarding treatment effect generally are best answered...

  15. Risk Factors for Atrial Fibrillation

    NARCIS (Netherlands)

    B.P. Krijthe (Bouwe)

    2013-01-01

    textabstractAtrial fibrillation is a common cardiac arrhythmia that is characterized by rapid disorganized atrial electrical activity resulting in absence of atrial contractions. It is diagnosed on the basis of typical findings on an electrocardiogram (ECG). The characteristic ECG findings are

  16. Genetic basis of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Oscar Campuzano

    2016-12-01

    Full Text Available Atrial fibrillation is the most common sustained arrhythmia and remains as one of main challenges in current clinical practice. The disease may be induced secondary to other diseases such as hypertension, valvular heart disease, and heart failure, conferring an increased risk of stroke and sudden death. Epidemiological studies have provided evidence that genetic factors play an important role and up to 30% of clinically diagnosed patients may have a family history of atrial fibrillation. To date, several rare variants have been identified in a wide range of genes associated with ionic channels, calcium handling protein, fibrosis, conduction and inflammation. Important advances in clinical, genetic and molecular basis have been performed over the last decade, improving diagnosis and treatment. However, the genetics of atrial fibrillation is complex and pathophysiological data remains still unraveling. A better understanding of the genetic basis will induce accurate risk stratification and personalized clinical treatment. In this review, we have focused on current genetics basis of atrial fibrillation.

  17. Signal analysis of ventricular fibrillation

    NARCIS (Netherlands)

    Herbschleb, J.N.; Heethaar, R.M.; Tweel, L.H. van der; Zimmerman, A.N.E.; Meijler, F.L.

    Signal analysis of electro(cardio)grams during ventricular fibrillation (VF) in dogs and human patients indicates more organization and regularity than the official WHO definition suggests. The majority of the signal is characterized by a power spectrum with narrow, equidistant peaks. In a further

  18. Ecobalances - essentials of a general regulation; Oekobilanzen - Grundzuege einer allgemeinen Regelung

    Energy Technology Data Exchange (ETDEWEB)

    Corino, C. [Landgericht Frankfurt am Main (Germany)

    1996-12-31

    An ecobalance (for products unfortunately also: Life cycle assessment-LCA) is to be understood as a comprehensive compilation of all environmental influences within a particular system and, if possible, also its environmental impacts. This article presents a method to perform ecobalances for enterprises, branches, products and services and their classes in a `tetra-system`. In the inventory input and output of material, energy and space of the system have to be determined. This is the basis for a quantitative method of evaluating the impacts. Notes to these balances provide methodological transparence, whereas a report on the position represents an improvement analysis. A verification of the prior steps guarantees comparability. The final publication of enterprise ecobalances and the labelling of products and services creates strong incentives for environmental improvement. A general regulation of this method could make the participation of enterprises voluntary or mandatory. Voluntary participation could be regulated by legislation or by private standards. On the other hand, a mandatory participation could be established only by binding law. A combination of law and private standards is not promising at present. Each of the different regulations seems to be quite effective, efficient and economically digestible, and most of the regulations do not pose legal problems. For some of them, however, conformity with the new world trading law, the EC Treaty and the German constitution may be doubted. Some other existing or planned regulatory structures such as Environmental Impact Assessment (EIA), Integrated Pollution Prevention and Control (IPPC), and the EC Eco-Audit, would need adjustment. The medium-term political acceptance of a general regulation on ecobalances seem to be rather good. (orig./SR) [Deutsch] Unter einer Oekobilanz ist die weitgehend vollstaendige Erfassung der Umweltbeeinflussungen und moeglichst auch der Umweltauswirkungen bestimmter Systeme zu

  19. Numerical optimisation of an axial turbine; Numerische Optimierung einer Axialturbine

    Energy Technology Data Exchange (ETDEWEB)

    Welzel, B.

    1998-12-31

    The author presents a method for automatic shape optimisation of components with internal or external flow. The method combines a program for numerical calculation of frictional turbulent flow with an optimisation algorithm. Algorithms are a simplex search strategy and an evolution strategy. The shape of the component to be optimized is variable due to shape parameters modified by the algorithm. For each shape, a flow calculation is carried out on whose basis a functional value like performance, loss, lift or resistivity is calculated. For validation, the optimisation method is used in simple examples with known solutions. It is applied. It is applied to the components of a slow-running axial turbine. Components with accelerated and delayed rotationally symmetric flow and 2D blade profiles are optimized. [Deutsch] Es wird eine Methode zur automatischen Formoptimierung durchstroemter oder umstroemter Bauteile vorgestellt. Diese koppelt ein Programm zur numerischen Berechnung reibungsbehafteter turbulenter Stroemungen mit einem Optimierungsalgorithmus. Dabei kommen als Algorithmen eine Simplex-Suchstrategie und eine Evolutionsstrategie zum Einsatz. Die Form des zu optimierenden Koerpers ist durch Formparameter, die vom Algorithmus veraendert werden, variabel. Fuer jede Form wird eine Stroemungsberechnung durchgefuehrt und mit dieser ein Funktionswert wie Wirkungsgrad, Verlust, Auftrieb oder Widerstandskraft berechnet. Die Optimierungsmethode wird zur Validierung in einfachen Beispielen mit bekannter Loesung eingesetzt. Zur Anwendung kommt sie in den einzelnen Komponenten einer langsamlaeufigen Axialturbine. Es werden Bauteile mit beschleunigter und verzoegerter rotationssymmetrischer Stroemung und 2D-Schaufelprofile optimiert. (orig.)

  20. Risk of atrial fibrillation in diabetes mellitus

    DEFF Research Database (Denmark)

    Pallisgaard, Jannik L; Schjerning, Anne-Marie; Lindhardt, Tommi B

    2016-01-01

    AIM: Diabetes has been associated with atrial fibrillation but the current evidence is conflicting. In particular knowledge regarding young diabetes patients and the risk of developing atrial fibrillation is sparse. The aim of our study was to investigate the risk of atrial fibrillation in patients...... with diabetes compared to the background population in Denmark. METHODS AND RESULTS: Through Danish nationwide registries we included persons above 18 years of age and without prior atrial fibrillation and/or diabetes from 1996 to 2012. The study cohort was divided into a background population without diabetes...... and a diabetes group. The absolute risk of developing atrial fibrillation was calculated and Poisson regression models adjusted for sex, age and comorbidities were used to calculate incidence rate ratios of atrial fibrillation. The total study cohort included 5,081,087 persons, 4,827,713 (95%) in the background...

  1. Chondroitin Sulfate Perlecan Enhances Collagen Fibril Formation

    DEFF Research Database (Denmark)

    Kvist, A. J.; Johnson, A. E.; Mörgelin, M.

    2006-01-01

    in collagen type II fibril assembly by perlecan-null chondrocytes. Cartilage perlecan is a heparin sulfate or a mixed heparan sulfate/chondroitin sulfate proteoglycan. The latter form binds collagen and accelerates fibril formation in vitro, with more defined fibril morphology and increased fibril diameters...... produced in the presence of perlecan. Interestingly, the enhancement of collagen fibril formation is independent on the core protein and is mimicked by chondroitin sulfate E but neither by chondroitin sulfate D nor dextran sulfate. Furthermore, perlecan chondroitin sulfate contains the 4,6-disulfated...... disaccharides typical for chondroitin sulfate E. Indeed, purified glycosaminoglycans from perlecan-enriched fractions of cartilage extracts contain elevated levels of 4,6-disulfated chondroitin sulfate disaccharides and enhance collagen fibril formation. The effect on collagen assembly is proportional...

  2. [Panic disorder and atrial fibrillation].

    Science.gov (United States)

    Olazabal Eizaguirre, N; Chavez, R; González-Torres, M A; Gaviria, M

    2013-10-01

    This paper studies the relationship between atrial fibrillation and panic disorder. There are often doubts on the differential diagnosis in emergency services and general medical settings. Panic disorder prevalence rates have been found to be high in patients suffering from atrial fibrillation. Various studies have observed that patients diagnosed with anxiety disorders frequently have higher cardiovascular disease rates compared to the general population. Usually, patients suffering from panic disorder exhibit somatic complaints suggesting coronary disease, such as chest pain or palpitations. The aim is to make the correct diagnosis and treatment for these different illnesses, and to decrease the costs due to misdiagnosis. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  3. Beiträge zu einer kognitiv ausgerichteten Lexikographie

    Directory of Open Access Journals (Sweden)

    Udo L. Figge

    2011-10-01

    Full Text Available

    Zusammenfassung: Nach einer "kognitiven Wende" in der Psychologie in der zweitenHälfte der sechziger Jahre haben auch Teile der Linguistik und der Psycholinguistik begonnen, sichkognitiv zu orientieren. Hier wird ein Modell zugrunde gelegt, nach dem sprachliche Einheiten aufEinheiten des Gedächtnisses referieren. Einheiten des Gedächtnisses sind zunächst Merkmale,sodann Konzepte, die sich aus Merkmalen konstituieren, und schließlich Gebilde von Merkmalen,Konzepten und Beziehungen zwischen Merkmalen. Eine solche Konzeption entspricht in denGrundzügen zeitgenössischen neuropsychologischen Erkenntnissen. Konzepte manifestieren sichin substantivischen Satzgliedern. Die Bedeutung eines Substantivs ist lexikographisch als Mengevon Merkmalen zu beschreiben, und zwar ohne Beachtung der ohnehin schwer zu rechtfertigendenUnterscheidung zwischen semantischem und enzyklopädischem Wissen. Die Bedeutungeines attributiven Adjektivs ist lexikographisch als Merkmal der Konzepte zu beschreiben, diedurch die zugehörigen Substantive ausgedrückt werden. Einem Verb liegt ein konverses Netz vonMerkmalen zugrunde; es muß lexikographisch dieser Bedeutung entsprechend beschrieben werden.Bei der Beschreibung von Substantiven ist systematisch zwischen echten Substantiven undsolchen Substantiven zu unterscheiden, die, meist als Ableitungen, eine verbale oder adjektivischeBedeutung haben. Insbesondere ist zu beachten, daß solche Substantive in Nebensatzäquivalentendie Funktion substantivischer Verbformen haben, daß sie weiterhin auch substantivische Bedeutungannehmen können und daß sie schließlich häufig Konstituenten von Stützverbgefügen sind.Die Bedeutung von Konjunktionen und von Präpositionen in Nebensatzäquivalenten kann nurnach einer exakten grammatischen Analyse verläßlich beschrieben werden. Texte werden unteranderem durch Textgliederungssignale gegliedert, die meist die Gestalt von Adverbien oder Adverbialenhaben. Diese

  4. Alginate-Collagen Fibril Composite Hydrogel

    Directory of Open Access Journals (Sweden)

    Mahmoud Baniasadi

    2015-02-01

    Full Text Available We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.

  5. The role of protonation in protein fibrillation

    DEFF Research Database (Denmark)

    Jeppesen, Martin D; Westh, Peter; Otzen, Daniel E

    2010-01-01

    Many proteins fibrillate at low pH despite a high population of charged side chains. Therefore exchange of protons between the fibrillating peptide and its surroundings may play an important role in fibrillation. Here, we use isothermal titration calorimetry to measure exchange of protons between...... buffer and the peptide hormone glucagon during fibrillation. Glucagon absorbs or releases protons to an extent which allows it to attain a net charge of zero in the fibrillar state, both at acidic and basic pH. Similar results are obtained for lysozyme. This suggests that side chain pKa values change...

  6. Stop-and-go kinetics in amyloid fibrillation

    DEFF Research Database (Denmark)

    Ferkinghoff-Borg, Jesper; Fonslet, Jesper; Andersen, Christian Beyschau

    2010-01-01

    Many human diseases are associated with protein aggregation and fibrillation. We present experiments on in vitro glucagon fibrillation using total internal reflection fluorescence microscopy, providing real-time measurements of single-fibril growth. We find that amyloid fibrils grow in an intermi......Many human diseases are associated with protein aggregation and fibrillation. We present experiments on in vitro glucagon fibrillation using total internal reflection fluorescence microscopy, providing real-time measurements of single-fibril growth. We find that amyloid fibrils grow...

  7. Untersuchung zur Konzeption einer elektrohydraulischen Energieversorgung für zukünftige Pkw-Bremssysteme

    OpenAIRE

    Mutschler, Robert

    1999-01-01

    Eine elektrohydraulische Energieversorgung für PKW-Bremssysteme wird vorgestellt. Diese Systeme können mit brake by wire klassifiziert werden. Die Energieversorgung besteht aus einem hydropneumatischen Speicher, einer Hochdruckpumpe und einem elektrischen Antrieb. Die Komponenten werden hinsichtlich Automobilanforderungen ausgelegt. Eine neue Methode der Minimierung hydraulischer Pulsationen, die von einer Hochdruck Kolbenpumpe verursacht werden, wird gezeigt.

  8. Therapie einer postoperativ entstandenen zystischen Raumforderung mit Picibanil (OK-432): Ein Fallbericht

    OpenAIRE

    Schlüter, A; Weller, P; Mattheis, S; Lang, S

    2014-01-01

    Einleitung: Picibanil (=OK432) ist ein Lysat bestehend aus Penicillin G und mit H2O2 attenuiertem Streptococcus pyogenes. In den letzten Jahrzehnten wurde Picibanil zur Therapie von Pleuraergüssen, Lymphangiomen, Chylusfisteln, medianen Halszysten und Ranulae eingesetzt. Es verursacht eine Immunreaktion mit aseptischer Entzündung. Dies führt zu einer Zerstörung des Endothels und konsekutiv zu einer Verklebung und Schrumpfung des Zystensacks.Falldarstellung: Wir berichten über einen 40-jähri...

  9. Haftung des "Director" einer englischen "Limited" gemäß § 64 GmbHG

    DEFF Research Database (Denmark)

    Ringe, Georg

    2016-01-01

    Für die Frage, ob und inwiefern auf EU-Auslandsgesellschaften inländisches Insolvenz- bzw. Gläubigerschutzrecht angewandt werden kann, differenziert der EuGH in seiner Entscheidung zwischen Vorschriften, die die Gründung der Gesellschaft und solchen, welche die spätere Tätigkeit betreffen. Wolf-G......-Georg Ringe (JZ 2016, 573) untersucht die Konsequenzen einer solchen Differenzierung und widerspricht dem Ergebnis des EuGH, der zur Anwendung des (insolvenzrechtlich qualifizierten) § 64 GmbHG im Fall einer englischen Limited kommt....

  10. Einfluss des Alltagskontextes auf den Prozess einer Ernährungsverhaltensmodifikation : eine qualitative Untersuchung von Personen mit erhöhten Cholesterinwerten

    OpenAIRE

    Hildebrandt, Karen

    2012-01-01

    Das erkenntnisleitende Forschungsinteresse gilt einer umfassenden Betrachtung ernährungsbezogenen Handelns in den drei Alltagsbereichen „Haushalt/Familie“, „Arbeitsplatz/Kollegen“ und „Freizeit/Freunde“ mit dem Ziel, individuell erlebte Bedingungen und Faktoren einer Ernährungsverhaltensmodifikation herauszuarbeiten. In die Untersuchung sind Personen mit einer Fettstoffwechselstörung eingeschlossen worden, die sich in verschiedenen Stadien einer Gesundheitsverhaltensmodifikation befinden. ...

  11. Aspects epidemiologiques et etiologiques de la fibrillation ...

    African Journals Online (AJOL)

    Conclusion : La fibrillation auriculaire est fréquente chez l'adulte noir togolais. Ses étiologies sont dominées par l'hypertension artérielle et les cardiomyopathies dilatées. complications and stoke. Aim: Our aim was to study epidemiologic and etiologic aspects of atrial fibrillation in black togolese in hospital circle. Material ...

  12. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, Rene; Hassenkam, Tue; P, Hansen

    2010-01-01

    Whole tendon and fibril bundles display viscoelastic behavior, but to the best of our knowledge this property has not been directly measured in single human tendon fibrils. In the present work an atomic force microscopy (AFM) approach was used for tensile testing of two human patellar tendon fibr...

  13. Fibril assembly in whey protein mixtures

    NARCIS (Netherlands)

    Bolder, S.G.

    2007-01-01

    The objective of this thesis was to study fibril assembly in mixtures of whey proteins. The effect of the composition of the protein mixture on the structures and the resulting phase behaviour was investigated. The current work has shown that beta-lactoglobulin is responsible for the fibril assembly

  14. Cetirizine-Induced atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Altuğ Osken

    2016-01-01

    Full Text Available Atrial fibrillation (AF is the most common observed arrhythmia in clinical practice. In the literature, AF events associated with drug induction are available. Cetirizine is a second-generation histamine antagonist used in the treatment of allergies, angioedema, and urticaria. We wish to present an atypical case who took cetirizine medication for relieving symptoms of upper tract respiratory system infection, experienced rapid ventricular response AF and treated successfully. To best of our knowledge, this is the first case of cetirizine-induced AF.

  15. Investigations regarding the mass budget in the propagation of a passive admixture from a line source; Untersuchungen zur Stoffbilanz bei der Ausbreitung einer passiven Beimengung aus einer Linienquelle

    Energy Technology Data Exchange (ETDEWEB)

    Wenzel, A. [Brandenburgische Technische Univ. Cottbus (Germany). Inst. fuer Boden-, Luft- und Gewaesserschutz

    1998-01-01

    Under stationary conditions, passive admixtures are transported by advection and by vertical as well as horizontal turbulent diffusion. The importance of individual contributions for the exchange of passive admixtures emanating from a straight line source with a constant source strength under neutral stratification conditions is discussed. For this purpose, all terms of the mass budget for a control volume around a straight line source are calculated using a stochastic Lagrange model (LS), whose properties are discussed. As a test for the LS model, the vertical and horizontal mass flows in the soil layer are simulated and compared with SANA data. The mass flows calculated for the propagation of a passive admixture from a line source are evaluated regarding their share of the mass budget. (orig.) [Deutsch] Unter stationaeren Bedingungen erfolgt der Transport von passiven Beimengungen durch Advektion sowie vertikale und horizontale turbulente Diffusion. Die Bedeutung der einzelnen Beitraege fuer den Austausch von passiven Beimengungen, die von einer geraden Linienquelle mit konstanter Quellstaerke unter neutralen Schichtungsbedingungen ausgehen, wird diskutiert. Dazu werden mit einem Lagrangeschen stochastischen (LS) Modell, dessen Eigenschaften besprochen werden, alle Terme der Stoffbilanz fuer ein Kontrollvolumen um eine gerade Linienquelle berechnet. Als Test fuer das LS-Modell werden die vertikalen und die horizontalen Stofffluesse in der Bodenschicht simuliert und mit SANA-Daten verglichen. Die fuer die Ausbreitung einer passiven Beimengung von einer Linienquelle berechneten Massenfluesse, werden hinsichtlich ihres Anteils an der Stoffbilanz ausgewertet. (orig.)

  16. Atrial fibrillation after cardiac surgery

    Directory of Open Access Journals (Sweden)

    Nair Suresh

    2010-01-01

    Full Text Available Once considered as nothing more than a nuisance after cardiac surgery, the importance of postoperative atrial fibrillation (POAF has been realized in the last decade, primarily because of the morbidity associated with the condition. Numerous causative factors have been described without any single factor being singled out as the cause of this complication. POAF has been associated with stroke, renal failure and congestive heart failure, although it is difficult to state whether POAF is directly responsible for these complications. Guidelines have been formulated for prevention of POAF. However, very few cardiothoracic centers follow any form of protocol to prevent POAF. Routine use of prophylaxis would subject all patients to the side effects of anti-arrhythmic drugs, while only a minority of the patients do actually develop this problem postoperatively. Withdrawal of beta blockers in the postoperative period has been implicated as one of the major causes of POAF. Amiodarone, calcium channel blockers and a variety of other pharmacological agents have been used for the prevention of POAF. Atrial pacing is a non-pharmacological measure which has gained popularity in the prevention of POAF. There is considerable controversy regarding whether rate control is superior to rhythm control in the treatment of established atrial fibrillation (AF. Amiodarone plays a central role in both rate control and rhythm control in postoperative AF. Newer drugs like dronedarone and ranazoline are likely to come into the market in the coming years.

  17. Atrial fibrillation and survival in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Justin Timothy A

    2004-11-01

    Full Text Available Abstract Background Survival in colorectal cancer may correlate with the degree of systemic inflammatory response to the tumour. Atrial fibrillation may be regarded as an inflammatory complication. We aimed to determine if atrial fibrillation is a prognostic factor in colorectal cancer. Patients and methods A prospective colorectal cancer patient database was cross-referenced with the hospital clinical-coding database to identify patients who had underwent colorectal cancer surgery and were in atrial fibrillation pre- or postoperatively. Results A total of 175 patients underwent surgery for colorectal cancer over a two-year period. Of these, 13 patients had atrial fibrillation pre- or postoperatively. Atrial fibrillation correlated with worse two-year survival (p = 0.04; log-rank test. However, in a Cox regression analysis, atrial fibrillation was not significantly associated with survival. Conclusion The presence or development of atrial fibrillation in patients undergoing surgery for colorectal cancer is associated with worse overall survival, however it was not found to be an independent factor in multivariate analysis.

  18. Method of an integrated and advanced evaluation of vulnerability. Conceptional-methodical fundamentals and examplary implementation for the water household, power generation and energetic utilisation of wood under climatic change; Methode einer integrierten und erweiterten Vulnerabilitaetsbewertung. Konzeptionell-methodische Grundlagen und exemplarische Umsetzung fuer Wasserhaushalt, Stromerzeugung und energetische Nutzung von Holz unter Klimawandel

    Energy Technology Data Exchange (ETDEWEB)

    Weisz, Helga; Koch, Hagen; Lasch, Petra [Potsdam-Institut fuer Klimafolgenforschung e.V. (Germany)] [and others

    2013-07-15

    Actually, in Germany there are more than hundred investigations on the consequences of the climatic change. It is difficult to evaluate the vulnerability of Germany against the climatic change. Under this aspect, the authors of the contributions report on a method of an integrated and advanced evaluation of vulnerability: Conceptional-methodical fundamentals and exemplary implementation for water household, power generation and energetic utilization of wood under climatic change.

  19. Sucrose modulates insulin amyloid-like fibril formation: effect on the aggregation mechanism and fibril morphology

    DEFF Research Database (Denmark)

    Marasini, Carlotta; Foderà, Vito; Vestergaard, Bente

    2017-01-01

    the protein self-assembly pathways. Using a combination of fluorescence spectroscopy, synchrotron radiation circular dichroism and transmission electron microscopy, we study the kinetics of formation and structural properties of human insulin fibrils in the presence of sucrose. The presence of sucrose results...... in a delay of the onset of fibrillation. Moreover, it leads to a dramatic change in both the morphology and overall amount of fibrils. Our results emphasize that the detailed composition of protein surroundings likely influences not only the fibrillation kinetics but also the balance between different...

  20. Ownership unbundling in the electric power industry. Reconcilability with German constitutional law and with EU law relating to German vertically integrated utilities; Ownership unbundling in der Energiewirtschaft. Vereinbarkeit einer eigentumsrechtlichen Entflechtung in der Energiewirtschaft mit den Grundrechten des Grundgesetzes und des Gemeinschaftsrechts deutscher vertikal integrierter Energieversorgungsunternehmen

    Energy Technology Data Exchange (ETDEWEB)

    Wachovius, Martin

    2008-07-01

    The publication investigates legal problems relating to ownership unbundling of vertically integrated utilities according to new EU law, especially the draft directive of the EU Commission of 19 September 2007. After a definition of the term and its historical development, the problem of law giving competence of the EU is discussed. Another issue is the problem if a new structure of European and German energy law is compatible with the basic laws defined in EU law and German constitutional law, namely with the principle of guarantee of ownership, professional freedom, and general freedom of action.

  1. Psychosomatic correlations in atrial fibrillations

    Directory of Open Access Journals (Sweden)

    Vladimir Ernstovich Medvedev

    2011-01-01

    Full Text Available Patients with atrial fibrillations (AF and comorbid mental disorders were examined. Two patient groups differing in the structure of psychosomatic ratios were identified. Group 1 comprised patients with AF and signs of reactivity lability that manifested itself as psychopathological reactions to the primary manifestations of AF; Group 2 included those who had developed mental disorders mainly in end-stage cardiovascular disease (predominantly a permanent form of AF in the presence of such events as chronic heart failure (CHF. The results of the study suggest that the patients with AF have frequently anxiety and hypochondriacal disorders, which agrees with the data available in the literature. In addition, end-stage AF is marked by depressive syndromes caused by the severe course of cardiovascular diseases resulting in CHF.

  2. Idiopathic ventricular tachycardia and fibrillation.

    Science.gov (United States)

    Belhassen, B; Viskin, S

    1993-06-01

    Important data have recently been added to our understanding of sustained ventricular tachyarrhythmias occurring in the absence of demonstrable heart disease. Idiopathic ventricular tachycardia (VT) is usually of monomorphic configuration and can be classified according to its site of origin as either right monomorphic (70% of all idiopathic VTs) or left monomorphic VT. Several physiopathological types of monomorphic VT can be presently individualized, according to their mode of presentation, their relationship to adrenergic stress, or their response to various drugs. The long-term prognosis is usually good. Idiopathic polymorphic VT is a much rarer type of arrhythmia with a less favorable prognosis. Idiopathic ventricular fibrillation may represent an underestimated cause of sudden cardiac death in ostensibly healty patients. A high incidence of inducibility of sustained polymorphic VT with programmed ventricular stimulation has been found by our group, but not by others. Long-term prognosis on Class IA antiarrhythmic medications that are highly effective at electrophysiologic study appears excellent.

  3. SINTAP: draft of a unified European failure assessment procedure. An introduction; SINTAP: Entwurf einer vereinheitlichten europaeischen Fehlerbewertungsprozedur. Eine Einfuehrung

    Energy Technology Data Exchange (ETDEWEB)

    Zerbst, U.; Kocak, M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung; Wiesner, C. [The Welding Institute (TWI), Cambridge (United Kingdom). Structural Integrity Dept.; Hodulak, L. [Fraunhofer-Institut fuer Werkstoffmechanik (IWM), Freiburg im Breisgau (Germany)

    1999-07-01

    Fracture mechanics based flaw assessment concepts are increasingly used in industrial regulations and standards. A considerable number of different guidelines and procedures are available which are partly based on each other but also exhibit significant differences. At this background, the EU sponsored SINTAP, an interdisciplinary Brite Euram project. SINTAP stands for 'Structural Integrity Assessment Procedures for European Industry'. From 1996 to 1999 seventeen organisations from nine European countries participated in the project the aim of which was to unify the available procedures. The present report is an introduction into the content, the structure and the scientific background of the procedure which was generated within SINTAP. (orig.) [German] Bruchmechanische Bewertungskonzepte werden international in zunehmendem Masse Bestandteil industrieller Regelwerke und Fachbereichsstandards. Bereits heute existiert eine Vielzahl derartiger Vorschriften und Rechnerprogramme, die teilweise aufeinander aufbauen, teilweise aber auch signifikante Unterschiede aufweisen. Vor diesem Hintergrund wurde durch die EU von 1996 bis 1999 SINTAP, ein interdisziplinaeres Brite-Euram-Projekt gefoerdert, dessen Ziel in einer Vereinheitlichung der vorhandenen Ansaetze bestand, und an dem siebzehn Institutionen aus neun europaeischen Laendern beteiligt waren. SINTAP steht fuer 'Structural Integrity Assessment Procedures for European Industry'. Der vorliegende Bericht ist eine Einfuehrung in Inhalt, Struktur und wissenschaftlichen Hintergrund der im Ergebnis des Projektes entstandenen SINTAP-Prozedur. (orig.)

  4. Atrial Fibrillation During an Exploration Class Mission

    Science.gov (United States)

    Lipsett, Mark; Hamilton, Douglas; Lemery, Jay; Polk, James

    2011-01-01

    This slide presentation reviews a possible scenario of an astronaut having Atrial Fibrillation during a Mars Mission. In the case review the presentation asks several questions about the alternatives for treatment, medications and the ramifications of the decisions.

  5. [Relations between FANS, PPI and atrial fibrillation].

    Science.gov (United States)

    Ricci, Fabrizio; De Caterina, Raffaele

    2013-05-01

    Recent evidence supports the existence of an association between the use of non-steroidal anti-inflammatory drugs and the risk of atrial fibrillation. Anti-inflammatory drugs are widely used for the treatment of systemic inflammatory disorders, and chronic inflammation is a well-known risk factor for the development of myocardial fibrosis. The latter accounts for atrial inhomogeneities of conduction, thus triggering and perpetuating atrial fibrillation. Atrial inflammatory remodeling may therefore be responsible for the higher incidence of atrial fibrillation among patients assuming steroidal and non-steroidal anti-inflammatory drugs because of an underlying inflammatory disorders. Alternative theories contemplate gastroesophageal reflux, which is extremely common during the use of non-steroidal anti-inflammatory drugs and may trigger atrial fibrillation, as mediating the above-mentioned association.

  6. Salbutamol Abuse is Associated with Ventricular Fibrillation

    Directory of Open Access Journals (Sweden)

    Emin UYSAL

    2015-06-01

    Full Text Available SUMMARY: Salbutamol-induced cardiac complications are well-established. Herein, we describe a case of a 24-year female who was admitted to the emergency department because of a suicide attempt with salbutamol (76 mg. Salbutamol abuse induced the development of supraventricular tachycardia and ventricular fibrillation. Regular sinus rhythm was restored with defibrillation. The hypokalemic patient who stayed in the intensive care unit was discharged after 48 hours of hospitalization. Key words: Salbutamol, suicide, ventricular fibrillation

  7. Chirality and chiroptical properties of amyloid fibrils.

    Science.gov (United States)

    Dzwolak, Wojciech

    2014-09-01

    Chirality of amyloid fibrils-linear beta-sheet-rich aggregates of misfolded protein chains-often manifests in morphological traits such as helical twist visible in atomic force microscopy and in chiroptical properties accessible to vibrational circular dichroism (VCD). According to recent studies the relationship between molecular chirality of polypeptide building blocks and superstructural chirality of amyloid fibrils may be more intricate and less deterministic than previously assumed. Several puzzling experimental findings have put into question earlier intuitive ideas on: 1) the bottom-up chirality transfer upon amyloidogenic self-assembly, and 2) the structural origins of chiroptical properties of protein aggregates. For example, removal of a single amino acid residue from an amyloidogenic all-L peptide was shown to reverse handedness of fibrils. On the other hand, certain types of amyloid aggregates revealed surprisingly strong VCD spectra with the sign and shape dependent on the conditions of fibrillation. Hence, microscopic and chiroptical studies have highlighted chirality as one more aspect of polymorphism of amyloid fibrils. This brief review is intended to outline the current state of research on amyloid-like fibrils from the perspective of their structural and superstructural chirality and chiroptical properties. © 2014 Wiley Periodicals, Inc.

  8. How Glycosaminoglycans Promote Fibrillation of Salmon Calcitonin*

    Science.gov (United States)

    Malmos, Kirsten Gade; Bjerring, Morten; Jessen, Christian Moestrup; Nielsen, Erik Holm Toustrup; Poulsen, Ebbe T.; Christiansen, Gunna; Vosegaard, Thomas; Skrydstrup, Troels; Enghild, Jan J.; Pedersen, Jan Skov; Otzen, Daniel E.

    2016-01-01

    Glycosaminoglycans (GAGs) bind all known amyloid plaques and help store protein hormones in (acidic) granular vesicles, but the molecular mechanisms underlying these important effects are unclear. Here we investigate GAG interactions with the peptide hormone salmon calcitonin (sCT). GAGs induce fast sCT fibrillation at acidic pH and only bind monomeric sCT at acidic pH, inducing sCT helicity. Increasing GAG sulfation expands the pH range for binding. Heparin, the most highly sulfated GAG, binds sCT in the pH interval 3–7. Small angle x-ray scattering indicates that sCT monomers densely decorate and pack single heparin chains, possibly via hydrophobic patches on helical sCT. sCT fibrillates without GAGs, but heparin binding accelerates the process by decreasing the otherwise long fibrillation lag times at low pH and accelerates fibril growth rates at neutral pH. sCT·heparin complexes form β-sheet-rich heparin-covered fibrils. Solid-state NMR reveals that heparin does not alter the sCT fibrillary core around Lys11 but makes changes to Val8 on the exterior side of the β-strand, possibly through contacts to Lys18. Thus GAGs significantly modulate sCT fibrillation in a pH-dependent manner by interacting with both monomeric and aggregated sCT. PMID:27281819

  9. Collagen Fibrils: Nature's Highly Tunable Nonlinear Springs.

    Science.gov (United States)

    Andriotis, Orestis G; Desissaire, Sylvia; Thurner, Philipp J

    2018-03-21

    Tissue hydration is well known to influence tissue mechanics and can be tuned via osmotic pressure. Collagen fibrils are nature's nanoscale building blocks to achieve biomechanical function in a broad range of biological tissues and across many species. Intrafibrillar covalent cross-links have long been thought to play a pivotal role in collagen fibril elasticity, but predominantly at large, far from physiological, strains. Performing nanotensile experiments of collagen fibrils at varying hydration levels by adjusting osmotic pressure in situ during atomic force microscopy experiments, we show the power the intrafibrillar noncovalent interactions have for defining collagen fibril tensile elasticity at low fibril strains. Nanomechanical tensile tests reveal that osmotic pressure increases collagen fibril stiffness up to 24-fold in transverse (nanoindentation) and up to 6-fold in the longitudinal direction (tension), compared to physiological saline in a reversible fashion. We attribute the stiffening to the density and strength of weak intermolecular forces tuned by hydration and hence collagen packing density. This reversible mechanism may be employed by cells to alter their mechanical microenvironment in a reversible manner. The mechanism could also be translated to tissue engineering approaches for customizing scaffold mechanics in spatially resolved fashion, and it may help explain local mechanical changes during development of diseases and inflammation.

  10. Modeling generic aspects of ideal fibril formation

    Energy Technology Data Exchange (ETDEWEB)

    Michel, D., E-mail: denis.michel@live.fr [Universite de Rennes1-IRSET, Campus de Beaulieu Bat. 13, 35042 Rennes (France)

    2016-01-21

    Many different proteins self-aggregate into insoluble fibrils growing apically by reversible addition of elementary building blocks. But beyond this common principle, the modalities of fibril formation are very disparate, with various intermediate forms which can be reshuffled by minor modifications of physico-chemical conditions or amino-acid sequences. To bypass this complexity, the multifaceted phenomenon of fibril formation is reduced here to its most elementary principles defined for a linear prototype of fibril. Selected generic features, including nucleation, elongation, and conformational recruitment, are modeled using minimalist hypotheses and tools, by separating equilibrium from kinetic aspects and in vitro from in vivo conditions. These reductionist approaches allow to bring out known and new rudiments, including the kinetic and equilibrium effects of nucleation, the dual influence of elongation on nucleation, the kinetic limitations on nucleation and fibril numbers, and the accumulation of complexes in vivo by rescue from degradation. Overlooked aspects of these processes are also pointed: the exponential distribution of fibril lengths can be recovered using various models because it is attributable to randomness only. It is also suggested that the same term “critical concentration” is used for different things, involved in either nucleation or elongation.

  11. RR-Interval variance of electrocardiogram for atrial fibrillation detection

    Science.gov (United States)

    Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

    2016-11-01

    Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

  12. On the role of fibril mechanics in the work of separation of fibrillating interfaces

    NARCIS (Netherlands)

    Vossen, B.G.; Sluis, van der O.; Schreurs, P.J.G.; Geers, M.G.D.; Neggers, J.; Hoefnagels, J.P.M.

    2015-01-01

    High values for the work of separation have been reported in peel tests on fibrillating interfacial systems. The exact origin of these high values is not properly understood, since it remains unclear which dissipative mechanisms related to fibrillation cause a significant increase in the work of

  13. Curcumin Protects β-Lactoglobulin Fibril Formation and Fibril-Induced Neurotoxicity in PC12 Cells.

    Directory of Open Access Journals (Sweden)

    Mansooreh Mazaheri

    Full Text Available In this study the β-lactoglobulin fibrillation, in the presence or absence of lead ions, aflatoxin M1 and curcumin, was evaluated using ThT fluorescence, Circular dichroism spectroscopy and atomic force microscopy. To investigate the toxicity of the different form of β-Lg fibrils, in the presence or absence of above toxins and curcumin, we monitored changes in the level of reactive oxygen species and morphology of the differentiated neuron-like PC12 cells. The cell viability, cell body area, average neurite length, neurite width, number of primary neurites, percent of bipolar cells and node/primary neurite ratios were used to assess the growth and complexity of PC12 cells exposed to different form of β-Lg fibrils. Incubation of β-Lg with curcumin resulted in a significant decrease in ROS levels even in the presence of lead ions and aflatoxin M1. The β-Lg fibrils formed in the presence of lead ions and aflatoxin M1 attenuated the growth and complexity of PC12 cells compared with other form of β-Lg fibrils. However, the adverse effects of these toxins and protein fibrils were negated in the presence of curcumin. Furthermore, the antioxidant and inhibitory effects of curcumin protected PC12 cells against fibril neurotoxicity and enhanced their survival. Thus, curcumin may provide a protective effect toward β-Lg, and perhaps other protein, fibrils mediated neurotoxicity.

  14. Persistent atrial fibrillation vs paroxysmal atrial fibrillation: differences in management.

    Science.gov (United States)

    Margulescu, Andrei D; Mont, Lluis

    2017-08-01

    Atrial fibrillation (AF) is the most common human arrhythmia. AF is a progressive disease, initially being nonsustained and induced by trigger activity, and progressing towards persistent AF through alteration of the atrial myocardial substrate. Treatment of AF aims to decrease the risk of stroke and improve the quality of life, by preventing recurrences (rhythm control) or controlling the heart rate during AF (rate control). In the last 20 years, catheter-based and, less frequently, surgical and hybrid ablation techniques have proven more successful compared with drug therapy in achieving rhythm control in patients with AF. However, the efficiency of ablation techniques varies greatly, being highest in paroxysmal and lowest in long-term persistent AF. Areas covered: In this review, we discuss the fundamental differences between paroxysmal and persistent AF and the potential impact of those differences on patient management, emphasizing the available therapeutic strategies to achieve rhythm control. Expert commentary: Treatment to prevent AF recurrences is suboptimal, particularly in patients with persistent AF. Emerging technologies, such as documentation of atrial fibrosis using magnetic resonance imaging and documentation of electrical substrate using advanced electrocardiographic imaging techniques are likely to provide valuable insights about patient-specific tailoring of treatments.

  15. Zur Rekonstruktion einer Typologie jugendlichen Medienhandelns gemäß dem Leitbild der Triangulation

    Directory of Open Access Journals (Sweden)

    Klaus Peter Treumann

    2017-09-01

    Full Text Available Die im Folgenden dargestellten Ergebnisse sind im Rahmen des von der DFG geförderten Forschungsprojekts „Eine Untersuchung zum Mediennutzungsverhalten 12- bis 20-Jähriger und zur Entwicklung von Medienkompetenz im Jugendalter“ entstanden, das gemeinsam von Klaus Peter Treumann, Uwe Sander und Dorothee Meister geleitet wird. Das Forschungsprojekt untersucht das Medienhandeln Jugendlicher sowohl hinsichtlich Neuer als auch alter Medien. Zum einen fragen wir dabei nach den Ausprägungen von Medienkompetenz in verschiedenen Dimensionen und zum anderen konzentrieren wir uns auf die Entwicklung einer empirisch fundierten Typologie jugendlichen Medienhandelns. Methodologisch ist die Untersuchung an dem Leitbild der Triangulation orientiert und kombiniert qualitative und quantitative Zugänge zum Forschungsfeld in Form von Gruppendiskussionen, leitfadengestützten Einzelinterviews und einer Repräsentativerhebung.

  16. Effect of age on stroke prevention therapy in patients with atrial fibrillation: the atrial fibrillation investigators

    DEFF Research Database (Denmark)

    van Walraven, Carl; Hart, Robert G; Connolly, Stuart

    2009-01-01

    contains patient level-data from randomized trials of stroke prevention in atrial fibrillation. We used Cox regression models with age as a continuous variable that controlled for sex, year of randomization, and history of cerebrovascular disease, diabetes, hypertension, and congestive heart failure......BACKGROUND AND PURPOSE: Stroke risk increases with age in patients who have nonvalvular atrial fibrillation. It is uncertain whether the efficacy of stroke prevention therapies in atrial fibrillation changes as patients age. The objective of this study was to determine the effect of age...... on the relative efficacy of oral anticoagulants (OAC) and antiplatelet (AP) therapy (including acetylsalicylic acid and triflusal) on ischemic stroke, serious bleeding, and vascular events in patients with atrial fibrillation. METHODS: This is an analysis of the Atrial Fibrillation Investigators database, which...

  17. Präoperative Vorhersge der Rezidivrate des klinisch lokalisierten Prostatakarzinoms nach einer radikalen Prostatektomie

    Directory of Open Access Journals (Sweden)

    Graefen M

    1999-01-01

    Full Text Available Die radikale Prostatektomie scheint die zur Zeit effektivste Therapie des klinisch lokalisierten Prostatakarzinoms zu sein. Dennoch liegt die Rezidivrate bei bis zu 40 % der operierten Patienten. Mit dieser Arbeit wurde anhand präoperativer Befunde ein Algorithmus entwickelt, mit welchem die Prognose des klinisch lokalisierten Prostatakarzinoms bereits vor einer operativen Therapie abgeschätzt werden kann. Hierzu wurden multiple präoperative Befunde, welche bei der Diagnose des Prostatakarzinoms erhoben werden, bezüglich ihres Einflusses auf einen PSA-Progress nach radikaler Prostatektomie geprüft. Dies erfolgte mittels einer univariaten Kaplan-Meier Analyse sowie einer multivariaten Statistik (Cox-Regression und CART-Analyse. Schwerpunkt bildete hierbei die Einbeziehung der Ergebnisse der systematischen Sextanten-Biopsie der Prostata. Alle präoperativen Befunde haben in der univariaten Kaplan-Meier Analyse einen signifikanten Einfluß auf ein PSA-Rezidiv. In der Cox-Regression hatte der Anteil an niedrigdifferenziertem Prostatakarzinom den größten Einfluß auf das Auftreten eines Tumorprogresses, gefolgt von der Anzahl der positiven Stanzen in der Biopsie und dem präoperativen PSA-Wert; alle anderen Parameter hatten keinen unabhängig signifikanten Einfluß auf den Tumorprogress. Mittels der zusätzlich durchgeführten CART Analyse konnten verschiedene Risikogruppen definiert werden, deren Rezidivrisiko bei 3 % für Patienten mit geringem Rezidivrisiko sowie 80 % für solche mit einem hohen Rezidivrisiko 2 Jahre nach der Operation betrug. Der niedrigdifferenzierte Tumoranteil hat somit den größten Einfluß auf die Prognose eines klinisch lokalisierten Prostatakarzinoms. Anhand der präsentierten CART-Analysen wurden einfach anwendbare Entscheidungsbäume entwickelt, mit denen eine Abschätzung des Therapieerfolges des klinisch lokalisierten Prostatakarzinoms bereits vor einer Operation möglich ist.

  18. Zur Konzeption kritischer Stadtforschung. Ansätze jenseits einer Eigenlogik der Städte

    Directory of Open Access Journals (Sweden)

    Jan Kemper

    2013-06-01

    Full Text Available Kritische Stadtforschung dient in Gestalt der „kritischen Stadtsoziologie“ gegenwärtig als Negativfolie für jene Stadtforschungsperspektive, die mit dem Postulat einer „Eigenlogik der Städte“ (EdS antritt. Eine (Selbst-Verständigung über konzeptionelle Grundlagen und forschungsstrategische Absichten einer kritischen Stadtforschung dagegen gibt es kaum. Ausgehend von dieser Beobachtung ist es das Ziel dieses Beitrags, zu einer Konturierung kritischer Stadtforschung beizutragen. Dafür skizzieren wir zunächst Eckpunkte der EdS-Perspektive. Anschließend wird ein Blick zurück auf den Klassiker Die Lage der arbeitenden Klasse in England (1845 von Friedrich Engels geworfen. Daran verdeutlichen wir drei Schritte in der Etablierung einer kritischen Haltung in der Stadtforschung: die Berücksichtigung der historisch-sozialen Voraussetzungen für gegenwärtige Stadtentwicklungsprozesse, die Analyse der städtischen Raum- und Sozialverhältnisse als krisen- und konfliktvermittelte und deshalb als dynamische Verhältnisse sowie die Konzeptionierung dieser Verhältnisse als veränderbar. An drei wiederkehrenden Diskussionsfeldern sozialwissenschaftlicher Stadtforschung schließlich verfolgen wir, wie einerseits die EdS-Perspektive sich dieser Themen annimmt und wie andererseits eine kritische Haltung im Umgang mit diesen Themen eingenommen werden kann. Für eine kritische Stadtforschung schlagen wir vor, (a „Stadt“ nicht als dauerhaft definiert und nicht als erklärend für sozialräumliche Verhältnisse zu begreifen, (b auch Städte als Räume zu konzipieren, die sich im gegenseitigen Wechselverhältnis mit Gesellschaft konstituieren, (c mit einem Konzept von Differenz, das Unterschiede sozial erklärt, zu arbeiten, wenn Städte als einzigartig erlebte Orte analysiert werden sollen.

  19. Konzept Gender Thesaurus. Zur Bedeutung einer gemeinsamen Dokumentationssprache für Forschung und Informationseinrichtungen

    Directory of Open Access Journals (Sweden)

    Jasmin Schenk

    2016-09-01

    Full Text Available Angesichts aktueller und voraussichtlich in naher Zukunft startender Infrastrukturprojekte der Frauen/Gender-Informationseinrichtungen einerseits und der Gender Studies andererseits, soll im Folgenden auf den Sinn und die Notwendigkeit einer gemeinsamen gendersensiblen Dokumentationssprache hingewiesen werden. Dieser Beitrag entstand im Rahmen des Masterstudiums der Bibliotheks- und Informationswissenschaften (MALIS an der Technischen Hochschule Köln und verfolgt das Ziel, Vorschläge für die Erarbeitung eines Gender Thesaurus zu entwickeln.

  20. Projekt Multimedia Storytelling. Konzeption und Umsetzung einer Content-Marketing-Plattform an der ETH-Bibliothek

    OpenAIRE

    Kyburz, Deborah

    2017-01-01

    Storytelling begeistert und macht als Methode von sich Reden. Die ETH-Bibliothek bediente sich des Storytelling für die Entwicklung und Umsetzung einer neuen Content-Marketing-Plattform namens Explora. Erzählt werden dort Geschichten zu digitalisierten Beständen der Sammlungen und Archive und zu Dienstleistungen der ETH-Bibliothek. Im Zentrum steht hierbei die Frage der attraktiven Präsentation des (Multimedia-)Contents. Der Beitrag skizziert, warum Storytelling und Wissenschaft eine geeignet...

  1. Panama: 100 Jahre Unabhängigkeit, Handlungsspielräume und Transformationsprozesse einer Kanalrepublik

    OpenAIRE

    Zoller, Rüdiger

    2015-01-01

    Während der 1990er Jahre standen die interamerikanischen Beziehungen auf Initiative des Amerikanisten Prof. Dr. Helmbrecht Breinig im Brennpunkt einer Reihe interdisziplinärer, von der DFG geförderter Forschungsvorhaben an der Universität Erlangen-Nürnberg. Den gemeinsamen konzeptionellen Rahmen für diese Teilprojekte entwickelte Prof. Dr. Friedrich von Krosigk mit seinen Überlegungen zu "Macht und Gegenmacht im Wandel interamerikanischer Beziehungen". Er selbst beteiligte sich mit einem Teil...

  2. Erstellung einer Checkliste zur Beurteilung des Arbeitsplatzes eines Physiotherapeuten nach ergonomischen Gesichtspunkten

    OpenAIRE

    Gauermann, Christoph

    2013-01-01

    Einleitung: Arbeitsbedingte Erkrankungen des Muskel-Skelett-Systems sind unter Physiotherapeuten sehr häufig. Die präventive Forschung hat diese Berufsgruppe bisher kaum untersucht. In diesem Zusammenhang stellt die Veränderung des Arbeitsumfeldes einen vielversprechenden Ansatz für die Verhinderung arbeitsbedingter Erkrankungen dar. Das Ziel dieser Arbeit ist die Erstellung einer Checkliste zur Bewertung des Arbeitsplatzes eines Physiotherapeuten zu erstellen. Material und Methoden: ...

  3. Implementierung einer Visualisierungsanwendung für Apples iOS

    OpenAIRE

    Felder, Christian

    2011-01-01

    Am Peter Grünberg Institut sowie am Jülich Centre for Neutron Science (JCNS) des Forschungszentrums Jülich ist schon seit Jahren eine standardisierte Grafikbibliothek im Einsatz, die auf einer Implementierung des grafischen Kernsystems (GKS) basiert. Zahlreiche Anwendungen und Programmschnittstellen aus dem Bereich der Instrumentierungs-, Simulations- und Auswertesoftware wurden auf der Basis dieser Bibliothek entwickelt, die sowohl von höhereren Programmiersprachen als auch gängigen Interpre...

  4. Von der Europäischen Rechtsgeschichte zu einer Rechtsgeschichte Europas in globalhistorischer Perspektive

    Directory of Open Access Journals (Sweden)

    Thomas Duve

    2012-01-01

    In den letzten Jahren sind im Zuge der Diskussion um postkoloniale Perspektiven auf die Geschichte, um Transnationale und Globalgeschichte, viele Grundlagen der traditionellen Europahistoriographie kritisiert und massiv erschüttert worden. Das wirft Fragen auch an die Europäische Rechtsgeschichte auf: Welches Europabild liegt ihr zu Grunde? Auf welchen intellektuellen und konzeptionellen Grundlagen beruht sie? Wie antwortet sie auf die Vorwürfe des Eurozentrismus, des epistemischen Kolonialismus, wie auf die Forderung, Europa zu ›provinzialisieren‹? Wie definiert sie das Verhältnis der Europäischen zur Transnationalen und Globalen Rechtsgeschichte? – Diesen und ähnlichen Fragen wenden sich die folgenden Überlegungen zu. Der Schwerpunkt liegt auf einer Auseinandersetzung mit der Tradition, ihren konzeptionellen Grundlagen und deren wissenschaftshistorischem Kontext (1. Teil, 1.–6.. Aus dieser kritischen Bestandsaufnahme und den Ergebnissen der Debatte um Globalgeschichte ergeben sich Ausgangspunkte und Aufgaben einer in Vielem auf den Leistungen der Disziplin aufbauenden, doch notwendigerweise auf einer anderen Konzeption beruhenden Rechtsgeschichte Europas in globalhistorischer Perspektive (2. Teil, 7.–11..

  5. "Neu lernen ist leichter als umlernen". Über die Schwierigkeiten einer bildungsgewohnten Gruppe, neue (mediale Partizipationsformen aufzubauen

    Directory of Open Access Journals (Sweden)

    Anna-Maria Kamin

    2011-10-01

    Full Text Available Das Internet bietet Lernenden vielfältige Möglichkeiten zur Wissensorganisation und -kommunikation in formalen und informellen Bildungskontexten. Bislang nutzen selbst bildungsaffine erwachsene Lerner diese unterstützenden Potenziale des Internets vielfach nur zurückhaltend. Dieser zögerliche Gebrauch zeigt sich auch dann, wenn die Implementierung virtuell vernetzter Applikationen in der Planung von den Lernenden von den Akteuren prinzipiell gefordert und begrüsst wird. Im Zentrum unseres Beitrags stehen mögliche Gründe und Bedingungen für diese vermeintlichen Widerstände und Problematiken bei der Integration des Partizipationsraums Internet für berufliche Lernprozesse. Grundlage für die Diskussion sind die Praxiserfahrungen und empirischen Ergebnisse einer explorativen Fall­studie mit einem ethisch beratenden Gremium. Die bisherige Bilanz des Projektvor­habens unterstreicht die Notwendigkeit, in diesem Kontext theoretische Konzepte zu Lernwiderständen, generationsspezifischen Aspekten, zur Mediendidaktik und zu Lerngewohnheiten und Transfer zu diskutieren. Die Ergebnisse belegen, dass digitale Lern- und Arbeitsformen unmittelbar an eingeschliffene Lernroutinen gebunden sind. Lernende benötigen Zeit, Raum, Anlässe und Struktur, um Handlungs- und Lernroutinen aufzubrechen und neue zu entwickeln. Nur so können digitale Partizipationsmöglichkeiten erfolgreich in den Arbeitsalltag integriert werden.

  6. Interaction of magnetic nanoparticles with lysozyme amyloid fibrils

    Energy Technology Data Exchange (ETDEWEB)

    Gdovinová, Veronika [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia); Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Tomašovičová, Natália, E-mail: nhudak@saske.sk [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia); Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Batko, Ivan; Batková, Marianna; Balejčíková, Lucia [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia); Garamus, Vasyl M. [Helmholtz-Zentrum Geesthacht: Zentrum fr Material, und Kstenforschung GmbH, Max-Plank-Strae 1, Geesthacht 216502 (Germany); Petrenko, Viktor I. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Physics Department, Taras Shevchenko Kyiv National University, Volodymyrska Street 64, 01601 Kyiv (Ukraine); Avdeev, Mikhail V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Kopčanský, Peter [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia)

    2017-06-01

    This work is devoted to the structural study of complex solutions of magnetic nanoparticles with lysozyme amyloid fibrils due to possible ordering of such system by applying the external magnetic field. The interaction of magnetic nanoparticles with amyloid fibrils has been followed by atomic force microscopy and small-angle X-ray scattering. It has been observed that magnetic nanoparticles (MNPs) adsorb to lysozyme amyloid fibrils. It was found that MNPs alter amyloids structures, namely the diameter of lysozyme amyloid fibrils is increased whereas the length of fibrils is decreased. In the same time MNPs do not change the helical pitch significantly. - Highlights: • Solution of MNPs with lysozyme amyloid fibrils was characterized by AFM and SAXS. • MNPs adsorb to lysozyme amyloid fibrils. • Diameter and size of lysozyme amyloid fibrils change due to doping with MNPs.

  7. Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

    Science.gov (United States)

    Nuryani, Nuryani; Satrio Nugroho, Anto

    2017-11-01

    Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

  8. Risk of atrial fibrillation and stroke in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Lindhardsen, Jesper; Ahlehoff, Ole; Gislason, Gunnar Hilmar

    2012-01-01

    To determine if patients with rheumatoid arthritis have increased risk of atrial fibrillation and stroke.......To determine if patients with rheumatoid arthritis have increased risk of atrial fibrillation and stroke....

  9. Treatment Guidelines of Atrial Fibrillation (AFib or AF)

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Treatment Guidelines of Atrial Fibrillation (AFib or AF) Updated:Jun 28,2017 What are the treatment guidelines for atrial fibrillation? Medical guidelines are written by ...

  10. Management of atrial fibrillation in the setting of heart failure

    NARCIS (Netherlands)

    Crijns, HJGM; VandenBerg, MP; VanGelder, IC; VanVeldhuisen, DJ

    Heart failure is often complicated by atrial fibrillation. Once atrial fibrillation has started it further enhances heart failure due to uncontrolled rate with shortened filling time and provocation of tachycardiomyopathy. Absent atrial kick and irregularity of the ventricular rhythm also

  11. Atrial and ventricular function after cardioversion of atrial fibrillation.

    Science.gov (United States)

    Xiong, C.; Sonnhag, C.; Nylander, E.; Wranne, B.

    1995-01-01

    OBJECTIVE--Previous studies on atrial recovery after cardioversion of atrial fibrillation have not taken into account new knowledge about the pathophysiology of transmitral and transtricuspid flow velocity patterns. It is possible to shed further light on this problem if atrioventricular inflow velocity, venous filling pattern, and atrioventricular annulus motion are recorded and interpreted together. DESIGN--Prospective examinations of mitral and tricuspid transvalvar flow velocities, superior caval and pulmonary venous filling, and mitral and tricuspid annulus motion were recorded using Doppler echocardiography. Examinations were performed before and 24 hours, 1 month, and 20 months after cardioversion. SETTING--Tertiary referral centre for cardiac disease with facilities for invasive and non-invasive investigation. PATIENTS--16 patients undergoing cardioversion of atrial fibrillation in whom sinus rhythm had persisted for 24 hours or more. RESULTS--Before conversion there was no identifiable A wave in transvalvar flow recordings. The total motion of the tricuspid and mitral annulus was subnormal and there was no identifiable atrial component. Venous flow patterns in general showed a low systolic velocity. After conversion, A waves and atrial components were seen in all patients and increased significantly (P atrial components, an increased systolic component of venous inflow, an increased A wave velocity, and a decreased E/A ratio of the transvalvar velocity curves. The ventricular component of annulus motion was unchanged. Changes in general occurred earlier on the right side than the left. CONCLUSIONS--This study indicates that, in addition to the previously known electromechanical dissociation of atrial recovery that exists after cardioversion of atrial fibrillation, there may also be a transient deterioration of ventricular function modulating the transvalvar inflow velocity recordings. Function on the right side generally becomes normal earlier than on the

  12. Rising rates of hospital admissions for atrial fibrillation

    DEFF Research Database (Denmark)

    Friberg, Jens; Buch, Nina Pernille Gardshodn; Scharling, Henrik

    2003-01-01

    Atrial fibrillation is a common arrhythmia associated with excess morbidity and mortality. We studied temporal changes in hospital admission rates for atrial fibrillation using data from a prospective population-based cohort study spanning 2 decades (the Copenhagen City Heart Study).......Atrial fibrillation is a common arrhythmia associated with excess morbidity and mortality. We studied temporal changes in hospital admission rates for atrial fibrillation using data from a prospective population-based cohort study spanning 2 decades (the Copenhagen City Heart Study)....

  13. Artificial atrial fibrillation in the dog. An artifact?

    NARCIS (Netherlands)

    Strackee, J.; Hoelen, A.J.; Zimmerman, A.N.E.; Meijler, F.L.

    R-R interval sequences during artificial atrial fibrillation in dogs were studied in the same way as in patients in a previous study and compared with results obtained in dogs with spontaneous atrial fibrillation. Artificial atrial fibrillation was effected by right atrial stimulation in three

  14. Alcohol consumption and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Tolstrup, Janne Schurmann; Wium-Andersen, Marie Kim; Ørsted, David Dynnes

    2016-01-01

    BACKGROUND: The aim of this study was to test the hypothesis that alcohol consumption, both observational (self-reported) and estimated by genetic instruments, is associated with a risk of atrial fibrillation and to determine whether people with high cardiovascular risk are more sensitive towards...... alcohol than people with low risk. METHODS: We used data for a total of 88,782 men and women from the Copenhagen City Heart Study 1991-1994 and 2001-2003 and the Copenhagen General Population Study 2003-2010. Information on incident cases of atrial fibrillation was obtained from a validated nationwide...... register. As a measure of alcohol exposure, both self-reported consumption and genetic variations in alcohol metabolizing genes (ADH1B/ADH1C) were used as instrumental variables. The endpoint was admission to hospital for atrial fibrillation as recorded in a validated hospital register. RESULTS: A total...

  15. The atrial fibrillation ablation pilot study

    DEFF Research Database (Denmark)

    Arbelo, Elena; Brugada, Josep; Hindricks, Gerhard

    2014-01-01

    AIMS: The Atrial Fibrillation Ablation Pilot Study is a prospective registry designed to describe the clinical epidemiology of patients undergoing an atrial fibrillation (AFib) ablation, and the diagnostic/therapeutic processes applied across Europe. The aims of the 1-year follow-up were to analyse...... was achieved in 40.7% of patients (43.7% in paroxysmal AF; 30.2% in persistent AF; 36.7% in long-lasting persistent AF). A second ablation was required in 18% of the cases and 43.4% were under antiarrhythmic treatment. Thirty-three patients (2.5%) suffered an adverse event, 272 (21%) experienced a left atrial...... tachycardia, and 4 patients died (1 haemorrhagic stroke, 1 ventricular fibrillation in a patient with ischaemic heart disease, 1 cancer, and 1 of unknown cause). CONCLUSION: The AFib Ablation Pilot Study provided crucial information on the epidemiology, management, and outcomes of catheter ablation of AFib...

  16. Antihypertensive treatment and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Marott, Sarah C W; Nielsen, Sune F; Benn, Marianne

    2014-01-01

    AIMS: To examine the associations between antihypertensive treatment with angiotensin-converting enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs), β-blockers, diuretics, or calcium-antagonists, and risk of atrial fibrillation. We examined these associations using the entire Danish...... population from 1995 through 2010. METHODS AND RESULTS: Excluding medication used in atrial fibrillation, we matched individuals on ACEi monotherapy 1:1 with individuals on β-blocker (n = 48 658), diuretic (n = 69 630), calcium-antagonist (n = 57 646), and ARB monotherapy (n = 20 158). Likewise, individuals...... on ARB monotherapy were matched 1:1 with individuals on β-blocker (n = 20 566), diuretic (n = 20 832), calcium-antagonist (n = 20 232), and ACEi monotherapy (n = 20 158). All were free of atrial fibrillation and of predisposing diseases like heart failure, ischaemic heart disease, diabetes mellitus...

  17. Digoxin for atrial fibrillation and atrial flutter

    DEFF Research Database (Denmark)

    Sethi, Naqash J; Nielsen, Emil E; Safi, Sanam

    2018-01-01

    BACKGROUND: During recent years, systematic reviews of observational studies have compared digoxin to no digoxin in patients with atrial fibrillation or atrial flutter, and the results of these reviews suggested that digoxin seems to increase the risk of all-cause mortality regardless...... of concomitant heart failure. Our objective was to assess the benefits and harms of digoxin for atrial fibrillation and atrial flutter based on randomized clinical trials. METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS, SCI-Expanded, BIOSIS for eligible trials comparing digoxin versus placebo......, no intervention, or other medical interventions in patients with atrial fibrillation or atrial flutter in October 2016. Our primary outcomes were all-cause mortality, serious adverse events, and quality of life. Our secondary outcomes were heart failure, stroke, heart rate control, and conversion to sinus rhythm...

  18. Atrial natriuretic peptide in patients with heart failure and chronic atrial fibrillation : Role of duration of at atrial fibrillation

    NARCIS (Netherlands)

    Van Den Berg, MP; Crijns, HJGM; Van Veldhuisen, DJ; Van Gelder, IC; De Kam, PJ; Lie, KI

    The purpose of this study was to analyze the determinants of atrial natriuretic peptide level in patients with congestive heart failure and atrial fibrillation. In particular, the duration of atrial fibrillation was analyzed because atrial fibrillation per se might have a specific effect on atrial

  19. Uniform spatial distribution of collagen fibril radii within tendon implies local activation of pC-collagen at individual fibrils

    Science.gov (United States)

    Rutenberg, Andrew D.; Brown, Aidan I.; Kreplak, Laurent

    2016-08-01

    Collagen fibril cross-sectional radii show no systematic variation between the interior and the periphery of fibril bundles, indicating an effectively constant rate of collagen incorporation into fibrils throughout the bundle. Such spatially homogeneous incorporation constrains the extracellular diffusion of collagen precursors from sources at the bundle boundary to sinks at the growing fibrils. With a coarse-grained diffusion equation we determine stringent bounds, using parameters extracted from published experimental measurements of tendon development. From the lack of new fibril formation after birth, we further require that the concentration of diffusing precursors stays below the critical concentration for fibril nucleation. We find that the combination of the diffusive bound, which requires larger concentrations to ensure homogeneous fibril radii, and lack of nucleation, which requires lower concentrations, is only marginally consistent with fully processed collagen using conservative bounds. More realistic bounds may leave no consistent concentrations. Therefore, we propose that unprocessed pC-collagen diffuses from the bundle periphery followed by local C-proteinase activity and subsequent collagen incorporation at each fibril. We suggest that C-proteinase is localized within bundles, at fibril surfaces, during radial fibrillar growth. The much greater critical concentration of pC-collagen, as compared to fully processed collagen, then provides broad consistency between homogeneous fibril radii and the lack of fibril nucleation during fibril growth.

  20. Patients with atrial fibrillation and permanent pacemaker

    DEFF Research Database (Denmark)

    Dalgaard, Frederik; Ruwald, Martin H; Lindhardt, Tommi Bo

    2018-01-01

    BACKGROUND: The management of patients with non-valvular atrial fibrillation (NVAF) with rate-lowering or anti-arrhythmic drugs has markedly changed over the last decade, but it is unknown how these changes have affected patients with NVAF with a permanent pacemaker (PPM). METHODS: Through Danish......,261. Thus, the proportional amount of NVAF patients with a PPM decreased from 1.3% to 1.1% (p = 0.015). Overall 45.9% had atrial fibrillation (AF) duration less than one year and the proportion declined from 55.5% to 42.4% (p

  1. Atrial fibrillation and risk of stroke

    DEFF Research Database (Denmark)

    Christiansen, Christine Benn; Gerds, Thomas A.; Olesen, Jonas Bjerring

    2016-01-01

    AIM: Although the relation between stroke risk factors and stroke in patients with atrial fibrillation (AF) has been extensively examined, only few studies have explored the association of AF and the risk of ischaemic stroke/systemic thromboembolism/transient ischaemic attack (stroke.......5-10.6), and 15.4% (14.5-16.4), respectively. CONCLUSIONS: Stroke/TE/TIA risk was particularly increased when prior stroke/TE/TIA was present. Atrial fibrillation is associated with an increase in risk of stroke/TE/TIA in the absence of other risk factors but only a moderate increase in risk when other risk...

  2. Initiation of anticoagulation in atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, A.; Staerk, L.; Fosbøl, E. L.

    2017-01-01

    Background: The use of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prophylaxis in atrial fibrillation (AF) is increasing rapidly. We compared characteristics of AF patients initiated on NOACs versus vitamin K antagonists (VKAs). Methods: Using Danish nationwide registry data, we...... compared with a VKA [odds ratio (OR) 1.35, 95% confidence interval (CI) 1.28–1.43]. By contrast, patients with a history of myocardial infarction were less likely to be initiated on a NOAC compared with a VKA (OR 0.72, 95% CI 0.67–0.77). Conclusions: Atrial fibrillation patients who were initiated...

  3. Atrial fibrillation and the 4P medicine.

    Science.gov (United States)

    Censi, Federica; Cianfrocca, Cinzia; Purificato, Ivana

    2013-01-01

    Although the paradigm of the 4P medicine - Predictive, Personalized, Preemptive, and Participatory - has been suggested several years ago, its application to atrial fibrillation is still far away. Given the increasing prevalence and incidence of this pathology it is the time to promote preventive strategies, by identifying the risk factors associated to life style and by incentivizing innovative diagnostic technologies. The promotion of the correct life style and of the use of diagnostic devices based on innovative and reliable technologies, represent a first step towards the full realization of the revolution of 4P medicine in atrial fibrillation.

  4. Atrial fibrillation and the 4P medicine

    Directory of Open Access Journals (Sweden)

    Federica Censi

    2013-09-01

    Full Text Available Although the paradigm of the 4P medicine - Predictive, Personalized, Preemptive, and Participatory - has been suggested several years ago, its application to atrial fibrillation is still far away. Given the increasing prevalence and incidence of this pathology it is the time to promote preventive strategies, by identifying the risk factors associated to life style and by incentivizing innovative diagnostic technologies. The promotion of the correct life style and of the use of diagnostic devices based on innovative and reliable technologies, represent a first step towards the full realization of the revolution of 4P medicine in atrial fibrillation.

  5. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, René; Hassenkam, Tue; Hansen, Philip

    2010-01-01

    Whole tendon and fibril bundles display viscoelastic behavior, but to the best of our knowledge this property has not been directly measured in single human tendon fibrils. In the present work an atomic force microscopy (AFM) approach was used for tensile testing of two human patellar tendon...... saline, cyclic testing was performed in the pre-yield region at different strain rates, and the elastic response was determined by a stepwise stress relaxation test. The elastic stress-strain response corresponded to a second-order polynomial fit, while the viscous response showed a linear dependence...

  6. Integration

    DEFF Research Database (Denmark)

    Emerek, Ruth

    2004-01-01

    Bidraget diskuterer de forskellige intergrationsopfattelse i Danmark - og hvad der kan forstås ved vellykket integration......Bidraget diskuterer de forskellige intergrationsopfattelse i Danmark - og hvad der kan forstås ved vellykket integration...

  7. New risk factors for atrial fibrillation : causes of 'not-so-lone atrial fibrillation'

    NARCIS (Netherlands)

    Schoonderwoerd, Bas A.; Smit, Marcelle D.; Pen, Lucas; Van Gelder, Isabelle C.

    Atrial fibrillation (AF) is a prevalent arrhythmia in patients with cardiovascular disease. The classical risk factors for developing AF include hypertension, valvular disease, (ischaemic) cardiomyopathy, diabetes mellitus, and thyroid disease. In some patients with AF, no underlying

  8. Protein Polymerization into Fibrils from the Viewpoint of Nucleation Theory.

    Science.gov (United States)

    Kashchiev, Dimo

    2015-11-17

    The assembly of various proteins into fibrillar aggregates is an important phenomenon with wide implications ranging from human disease to nanoscience. Using general kinetic results of nucleation theory, we analyze the polymerization of protein into linear or helical fibrils in the framework of the Oosawa-Kasai (OK) model. We show that while within the original OK model of linear polymerization the process does not involve nucleation, within a modified OK model it is nucleation-mediated. Expressions are derived for the size of the fibril nucleus, the work for fibril formation, the nucleation barrier, the equilibrium and stationary fibril size distributions, and the stationary fibril nucleation rate. Under otherwise equal conditions, this rate decreases considerably when the short (subnucleus) fibrils lose monomers much more frequently than the long (supernucleus) fibrils, a feature that should be born in mind when designing a strategy for stymying or stimulating fibril nucleation. The obtained dependence of the nucleation rate on the concentration of monomeric protein is convenient for experimental verification and for use in rate equations accounting for nucleation-mediated fibril formation. The analysis and the results obtained for linear fibrils are fully applicable to helical fibrils whose formation is describable by a simplified OK model. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Metastable Amyloid Phases and their Conversion to Mature Fibrils

    Science.gov (United States)

    Muschol, Martin; Miti, Tatiana; Mulaj, Mentor; Schmit, Jeremy

    Self-assembly of proteins into amyloid fibrils plays a key role in both functional biological responses and pathogenic disorders which include Alzheimer's disease and type II diabetes. Amyloid fibril assembly frequently generates compact oligomeric and curvilinear polymeric intermediates which are implicated to be toxic to cells. Yet, the relation between these early-stage oligomeric aggregates and late-stage rigid fibrils, which are the hallmark structure of amyloid plaques, has remained unclear. Our measurements indicate that lysozyme amyloid oligomers and their curvilinear fibrils only form after crossing a salt and protein concentration dependent threshold. These oligomeric aggregates are structurally distinct from rigid fibrils and are metastable against nucleation and growth of rigid fibrils. Our experimental transition boundaries match well with colloidal model predictions accounting for salt-modulated charge repulsion. We also report our preliminary findings on the mechanism by which these metastable oligomeric phases are converted into stable amyloid fibrils.

  10. Embolic Risk in Atrial Fibrillation that Arises from Hyperthyroidism

    Science.gov (United States)

    Traube, Elie; Coplan, Neil L.

    2011-01-01

    Atrial fibrillation, the most common cardiac complication of hyperthyroidism, occurs in an estimated 10% to 25% of overtly hyperthyroid patients. The prevalence of atrial fibrillation increases with age in the general population and in thyrotoxic patients. Other risk factors for atrial fibrillation in thyrotoxic patients include male sex, ischemic or valvular heart disease, and congestive heart failure. The incidence of arterial embolism or stroke in thyrotoxic atrial fibrillation is less clear. There are many reports of arterial thromboembolism associated with hyperthyroidism, including cases of young adults without coexisting risk factors other than thyrotoxic atrial fibrillation. The use of anticoagulative agents to prevent thromboembolic sequelae of thyrotoxic atrial fibrillation is controversial: national organizations provide conflicting recommendations in their practice guidelines. Herein, we review the medical literature and examine the evidence behind the recommendations in order to determine the best approach to thromboembolic prophylaxis in patients who have atrial fibrillation that is associated with hyperthyroidism. PMID:21720457

  11. Decreasing emissions of a secondary lead smelter by installation of a battery breaker. Emissionsminderung einer Sekundaerbleihuette durch Integration einer Akkuschrott-Aufbereitung

    Energy Technology Data Exchange (ETDEWEB)

    Lamm, K F

    1986-11-01

    Dust and lead emissions of a secondary lead smelter mainly from the area of stockyards, handling, transport, charge preparing as well as the further treatment in rotary furnaces. A 60% decrease is obtained by compact assembling of covered battery stockyard, battery breaker and charge preparation and direct connection to the existing smelter area. The breaker itself contains a wet screen trommel and a filter press for separation of paste. The heavy-media sink-float-system has been replaced by dynamic water separation, which results in cleaner qualities of all fractions. In spite of a 100% wet separation plant, a bagfilter can be used with expected clean gas dust contents below 5 mg/m{sup 3} and below 2.5 mg Pb/m{sup 3}. Over a 2 years-period, dust and lead contents have been below 1 mg/m{sup 3}. (orig.) With 5 refs., 2 flowsheets, 10 figs.

  12. Spontaneous conversion of first onset atrial fibrillation

    DEFF Research Database (Denmark)

    Lindberg, Søren Østergaard; Hansen, Sidsel; Nielsen, Tonny

    2011-01-01

    Background  We studied all patients admitted to hospital with first onset atrial fibrillation (AF) to determine the probability of spontaneous conversion to sinus rhythm and to identify factors predictive of such a conversion. Methods and Results  We retrospectively reviewed charts of 438...

  13. Genetic aspects of lone atrial fibrillation

    DEFF Research Database (Denmark)

    Andreasen, Laura; Nielsen, Jonas B; Olesen, Morten S

    2015-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia. A subgroup of patients presents with AF without traditional risk factors and is diagnosed before the age of 60 years. Such patients are commonly referred as having "lone AF" and comprise 10-20% of all cases. A number of studies have...

  14. Atrial fibrillation in the Middle East

    DEFF Research Database (Denmark)

    Al-Shamkhani, Warkaa; Ayetey, Harold; Lip, Gregory Y H

    2018-01-01

    INTRODUCTION: Atrial fibrillation (AF) is the commonest persistent cardiac arrhythmia with an estimated incidence rate of between 1.5-2% and an important cause of strokes. Few epidemiological studies and clinical trials on the management of AF have been conducted outside Europe and North America...

  15. An "account" of digitalis and atrial fibrillation

    NARCIS (Netherlands)

    Meijler, F.L.

    This review deals with the mechanisms by which digitalis exerts its "opium-Iike" action on the ventricular rate in patients with atrial fibrillation. To understand the effect of digitalis on ventricular rate and rhythm, it is essential to learn more about the basic electrophysiologic

  16. SAS-Based Studies of Protein Fibrillation

    DEFF Research Database (Denmark)

    Marasini, Carlotta; Vestergaard, Bente

    2017-01-01

    Protein fibrillation is associated with a number of fatal amyloid diseases (e.g. Alzheimer's and Parkinson's diseases). From a structural point of view, the aggregation process starts from an ensemble of native states that convert into transiently formed oligomers, higher order assemblies and pro...... and highlight existing reports, exemplifying the wealth of information that can be derived from the method....

  17. Aggregation and fibrillation of bovine serum albumin

    DEFF Research Database (Denmark)

    Holm, NK; Jespersen, SK; Thomassen, LV

    2007-01-01

    The all-alpha helix multi-domain protein bovine serum albumin (BSA) aggregates at elevated temperatures. Here we show that these thermal aggregates have amyloid properties. They bind the fibril-specific dyes Thioflavin T and Congo Red, show elongated although somewhat worm-like morphology...

  18. Über den Nachrichtenwert von Friedensjournalismus - Ergebnisse einer experimentellen Studie

    Directory of Open Access Journals (Sweden)

    Monika Spohrs

    2006-04-01

    Full Text Available Laut Nachrichtenwertforschung hängt die Publikations- und Lesenswürdigkeit von Nachrichtentexten von den Nachrichtenfaktoren der zu publizierenden Ereignisse ab. Als anerkannte Nachrichtenfaktoren gelten beispielsweise Negativität, Vereinfachung und Personifizierung. Friedensjournalistische Arbeiten weichen von diesen Kriterien oft ab, indem sie versuchen, die berichteten Ereignisse in ihrer Komplexität darzustellen, den Fokus nicht auf negative Ereignisse zu legen und auch strukturellen Themen Raum zu geben. Aber sind sie deshalb weniger publikationswürdig? Der folgende Artikel zeigt anhand einer experimentellen Studie, welche Akzeptanz Friedensjournalismus beim Leser finden kann, auch wenn dies teilweise den Theorien der Nachrichtenwertforschung widerspricht. Des weiteren wird gezeigt, wie sich konstruktive Berichterstattung auf die mentalen Modelle der Rezipienten auswirkt und in welchem Zusammenhang diese beiden Ergebnisse miteinander stehen. In der vorliegenden Studie wurden einer für die Leserschaft der deutschen Qualitätspresse hinsichtlich Alter und Bildungsgrad repräsentativen Stichprobe von n = 128 Versuchspersonen Zeitungsartikel zu drei verschiedenen Ereignissen im Konfliktfeld des ehemaligen Jugoslawien dargeboten. Zu jedem Ereignis wurden vier verschiedene Textvarianten verwendet: eine gemäßigt eskalationsorientierte Originalfassung aus einer deutschen Qualitätszeitung (Die Welt, Frankfurter Allgemeine Zeitung, Süddeutsche Zeitung und drei modifizierte Versionen dieser Artikel, (a mit gemäßigt deeskalations-orientiertem Framing, (b mit stark deeskalationsorientiertem Framing und (c mit einer Verschärfung der Eskalationsorientierung der dargestellten Konflikte. Die Aufgabe der Vpn bestand darin, zu jedem der drei Ereignisse eine Textvariante zu lesen und danach in eigenen Worten schriftlich wiederzugeben und anschließend einen Fragebogen zu Akzeptanz, Glaubwürdigkeit, Ausgewogenheit, Neuigkeitsgehalt, Bewertung und

  19. [Cardiodoron® bei Patienten mit Schlafstörungen - Ergebnisse einer prospektiven Beobachtungsstudie].

    Science.gov (United States)

    Rother, Claudia; Schnelle, Martin

    Hintergrund: Schlafstörungen gehören zu den häufigsten gesundheitlichen Problemen der heutigen Zeit. Stress und die dadurch bedingte innere Anspannung sowie eine unrhythmische Lebensführung z.B. durch Schichtarbeit sind bekannte auslösende Faktoren. Weniger bekannt ist, dass auch funktionelle Herz-Kreislauf-Beschwerden zu Störungen des Schlafs führen können und dass deren Behandlung zu einer Verbesserung der Schlafqualität beiträgt. Ganzheitlich betrachtet geht es daher um die Wiederherstellung einer gesunden Rhythmik, insbesondere des Herz-/Atem- sowie des Schlaf-Wach-Rhythmus, die Cardiodoron®, eine Heilpflanzenkomposition aus Primula veris, Hyoscyamus niger und Onopordum acanthium, unterstützt. Patienten und Methoden: Mittels einer prospektiven, multizentrischen Beobachtungsstudie sollte ermittelt werden, wie sich funktionelle Herz-Kreislauf-Beschwerden und/oder Schlafstörungen unter der Behandlung mit Cardiodoron® (Dilution) über 3-6 Monate entwickeln. Im Zeitraum von September 2009 bis März 2012 dokumentierten 92 Ärzte 501 Patienten, von denen 380 über Schlafstörungen klagten und deren Daten in dieser Publikation näher betrachtet werden. Nach einer Aufnahmeuntersuchung erfolgte nach 90 Tagen eine Abschlussuntersuchung und bei Fortführung der Therapie nach nochmals 90 Tagen eine Follow-up-Untersuchung. Neben 30 ärztlicherseits bewerteten Symptomen beurteilten die Patienten ihr Befinden mittels Pittsburgh Sleep Quality Index (PSQI) nach Buysse und der Beschwerden-Liste nach von Zerssen (B-L und B-L'). Ergebnisse: Unter der Cardiodoron®-Therapie gingen bei guter Verträglichkeit sowohl die Ausprägung der Schlafstörungen (um 65% von 2,0 auf 0,7 Punkte) als auch die erfassten 30 Symptome (um 59% von 24,3 auf 9,9 Punkte) deutlich zurück (p mit Schlafstörungen (mit oder ohne funktionelle Herz-Kreislauf-Beschwerden) kann die Ausprägung der Beschwerden mit Cardiodoron® deutlich gesenkt werden. Cardiodoron® ist gut verträglich. © 2016 S

  20. Untersuchungen zum Einfluss einer Air-Liquid-Interphase auf die Differenzierung von Alveolarepithelzellen Typ II

    OpenAIRE

    Sinis, Nektarios

    2003-01-01

    Die Dedifferenzierung der Alveolarepithelzellen Typ II stellt in vitro ein großes Problem dar. Zellen, die länger als 48 Stunden in vitro kultiviert werden tendieren zu einer Dedifferenzierung. Die vorliegende Arbeit stellt ein Air-Liquid-Interphasesystem zur Kultivierung von TypII-Zellen vor. Hierdurch ist es uns gelungen TypII-Zellen über einen Zeitraum von bis zu 14 Tagen in vitro auf einem hohen Grad der Differenzierung zu konservieren. Zellen die nicht so kultiviert wurden zeigten fr...

  1. Kinetics and mechanical stability of the fibril state control fibril formation time of polypeptide chains: A computational study

    Science.gov (United States)

    Kouza, Maksim; Co, Nguyen Truong; Li, Mai Suan; Kmiecik, Sebastian; Kolinski, Andrzej; Kloczkowski, Andrzej; Buhimschi, Irina Alexandra

    2018-06-01

    Fibril formation resulting from protein misfolding and aggregation is a hallmark of several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. Despite much progress in the understanding of the protein aggregation process, the factors governing fibril formation rates and fibril stability have not been fully understood. Using lattice models, we have shown that the fibril formation time is controlled by the kinetic stability of the fibril state but not by its energy. Having performed all-atom explicit solvent molecular dynamics simulations with the GROMOS43a1 force field for full-length amyloid beta peptides Aβ40 and Aβ42 and truncated peptides, we demonstrated that kinetic stability can be accessed via mechanical stability in such a way that the higher the mechanical stability or the kinetic stability, the faster the fibril formation. This result opens up a new way for predicting fibril formation rates based on mechanical stability that may be easily estimated by steered molecular dynamics.

  2. [Integrity].

    Science.gov (United States)

    Gómez Rodríguez, Rafael Ángel

    2014-01-01

    To say that someone possesses integrity is to claim that that person is almost predictable about responses to specific situations, that he or she can prudentially judge and to act correctly. There is a closed interrelationship between integrity and autonomy, and the autonomy rests on the deeper moral claim of all humans to integrity of the person. Integrity has two senses of significance for medical ethic: one sense refers to the integrity of the person in the bodily, psychosocial and intellectual elements; and in the second sense, the integrity is the virtue. Another facet of integrity of the person is la integrity of values we cherish and espouse. The physician must be a person of integrity if the integrity of the patient is to be safeguarded. The autonomy has reduced the violations in the past, but the character and virtues of the physician are the ultimate safeguard of autonomy of patient. A field very important in medicine is the scientific research. It is the character of the investigator that determines the moral quality of research. The problem arises when legitimate self-interests are replaced by selfish, particularly when human subjects are involved. The final safeguard of moral quality of research is the character and conscience of the investigator. Teaching must be relevant in the scientific field, but the most effective way to teach virtue ethics is through the example of the a respected scientist.

  3. Kinetically controlled thermal response of beta2-microglobulin amyloid fibrils.

    Science.gov (United States)

    Sasahara, Kenji; Naiki, Hironobu; Goto, Yuji

    2005-09-23

    Calorimetric measurements were carried out using a differential scanning calorimeter in the temperature range from 10 to 120 degrees C for characterizing the thermal response of beta2-microglobulin amyloid fibrils. The thermograms of amyloid fibril solution showed a remarkably large decrease in heat capacity that was essentially released upon the thermal unfolding of the fibrils, in which the magnitude of negative heat capacity change was not explicable in terms of the current accessible surface area model of protein structural thermodynamics. The heat capacity-temperature curve of amyloid fibrils prior to the fibril unfolding exhibited an unusual dependence on the fibril concentration and the heating rate. Particularly, the heat needed to induce the thermal response was found to be linearly dependent on the heating rate, indicating that its thermal response is under a kinetic control and precluding the interpretation in terms of equilibrium thermodynamics. Furthermore, amyloid fibrils of amyloid beta peptides also exhibited a heating rate-dependent exothermic process before the fibril unfolding, indicating that the kinetically controlled thermal response may be a common phenomenon to amyloid fibrils. We suggest that the heating rate-dependent negative change in heat capacity is coupled to the association of amyloid fibrils with characteristic hydration pattern.

  4. [COPD und Klangtherapie: Pilotstudie zur Wirksamkeit einer Behandlung mit Körpertambura bei COPD-Patienten].

    Science.gov (United States)

    Hartwig, Bernhard; Schmidt, Stefan; Hartwig, Isabella

    2016-01-01

    Hintergrund: Erkrankungen der Atemorgane treten mit steigendem Alter öfter auf, nehmen weltweit zu und sind häufige Ursachen für Morbidität und Mortalität. In dieser Pilotstudie wurde der Frage nachgegangen, ob eine einmalige 10-minütige Behandlung mit einer Körpertambura eine signifikante und effektive Verbesserung der Lungenfunktion von Patienten mit chronisch-obstruktiver Lungenerkrankung (COPD; GOLD-Stadium A oder B) erbringen kann. Patienten und Methoden: 54 Probanden konnten je zur Hälfte in eine Behandlungsgruppe (Körpertambura) und eine aktive Kontrollgruppe (Atemtherapie) randomisiert werden. Eine Bestimmung der Lungenfunktionsmessparameter «Einsekundenkapazität» (FEV1) und «inspiratorische Vitalkapazität» (IVC) zu den Zeitpunkten T1 (Baseline), T2 (direkt nach Behandlung) und als Follow-up etwa 3 Wochen nach T1 (T3). Ergebnisse: Die Behandlungsgruppe zeigte sich der Kontrollgruppe in beiden Werten signifikant überlegen. Die Zeit-×-Gruppe-Interaktion (Varianzanalyse) ergab p = 0,001 (FEV1) bzw. p = 0,04 (IVC). Die Behandlungsgruppe zeigte bei beiden Werten eine Verbesserung von klinischer Relevanz. Schlussfolgerung: Diese Ergebnisse zeigen, dass die Klangbehandlung mittels einer Körpertambura - neben den schulmedizinischen, leitliniengerechten Therapien - eine zusätzliche, nebenwirkungsarme, aber durchaus klinisch wirksame Option für die Behandlung von COPD-Patienten darstellen kann, um deren Lebensqualität zu stabilisieren und zu verbessern. © 2016 S. Karger GmbH, Freiburg.

  5. "Doing pupil" nach Schulschluss – Videografie an einer Kinderuniversität

    Directory of Open Access Journals (Sweden)

    Alexandra König

    2015-03-01

    Full Text Available Auf der Basis einer Videografie an einer Kinderuniversität wird in dem vorliegenden Beitrag die Frage verfolgt, wie an einem außerschulischen Lernort generationale Ordnung hergestellt wird und welche Gestalt diese annimmt. Als heuristischer Rahmen dient das Modell der "Sozialisation als generationales Ordnen" (BÜHLER-NIEDERBERGER 2011; BÜHLER-NIEDERBERGER & TÜRKYILMAZ 2014. Die Analyse der ersten Sitzungen von zwei kontrastiven Kursen an der Kinder- und Jugenduniversität zeigt erstens, wie Kinder struktursensitiv Regeln in dem unbekannten Kontext erspüren, erarbeiten und modifizieren, wie sie KomplizInnen in der Herstellung generationaler Ordnung sind. Zweitens wird die Dominanz der schulischen Ordnung und des SchülerInnenstatus für Kindheit deutlich. Die Kinder stellen "Schule" her – paradoxerweise auch in einem außerschulischen Kontext. Drittens wird im kontrastiven Vergleich der untersuchten Kurse eine Varianz dieser Ordnungen – in Bezug auf die Form des Wissens und Adressierung der Kinder – herausgearbeitet, die allerdings die Dominanz der schulischen Ordnung nicht bricht. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs150263

  6. Synthese von analogen Filtern auf einer rekonfigurierbaren Hardware-Architektur mittels eines Genetischen Algorithmus

    Directory of Open Access Journals (Sweden)

    S. Trendelenburg

    2008-05-01

    Full Text Available Rekonfigurierbare Analog-Arrays (FPAAs sind der Versuch, die Vorteile der aus der digitalen Welt bekannten FPGAs (Flexibilität, Entwurfsgeschwindigkeit auch für analoge Anwendungen verfügbar zu machen. Aufgrund der Vielfalt der analogen Schaltungstechnik ist die Abbildung von vorgegebenen Schaltungskonzepten auf eine FPAA-Architektur nicht immer einfach lösbar.

    Diese Arbeit stellt einen neuen Ansatz für die Synthese von Filtern auf einer FPAA-Architektur für zeitkontinuierliche Analogfilter mittels eines Genetischen Algorithmus (GA vor. Anhand eines Matlab-Modells des FPAA, das eine gute übereinstimmung mit Simulationen des FPAA auf Transistorebene aufweist, wurde gezeigt, dass eine große Vielzahl verschiedener Filterstrukturen auf dieser Architektur dargestellt werden kann. Daraufhin wurde ein Genetischer Algorithmus entwickelt, der es erlaubt, aus einer gegebenen Filterspezifikation Konfigurationsdatensätze zu synthetisieren, die den gewünschten Filter auf die FPAA-Architektur abbilden.

  7. Opposed Effects of Dityrosine Formation in Soluble and Aggregated α-Synuclein on Fibril Growth.

    Science.gov (United States)

    Wördehoff, Michael M; Shaykhalishahi, Hamed; Groß, Luca; Gremer, Lothar; Stoldt, Matthias; Buell, Alexander K; Willbold, Dieter; Hoyer, Wolfgang

    2017-10-13

    Parkinson's disease is the second most common neurodegenerative disease. It is characterized by aggregation of the protein α-synuclein (α-syn) in Lewy bodies, mitochondrial dysfunction, and increased oxidative stress in the substantia nigra. Oxidative stress leads to several modifications of biomolecules including dityrosine (DiY) crosslinking in proteins, which has recently been detected in α-syn in Lewy bodies from Parkinson's disease patients. Here we report that α-syn is highly susceptible to ultraviolet-induced DiY formation. We investigated DiY formation of α-syn and nine tyrosine-to-alanine mutants and monitored its effect on α-syn fibril formation in vitro. Ultraviolet irradiation of intrinsically disordered α-syn generates DiY-modified monomers and dimers, which inhibit fibril formation of unmodified α-syn by interfering with fibril elongation. The inhibition depends on both the DiY group and its integration into α-syn. When preformed α-syn fibrils are crosslinked by DiY formation, they gain increased resistance to denaturation. DiY-stabilized α-syn fibrils retain their high seeding efficiency even after being exposed to denaturant concentrations that completely depolymerize non-crosslinked seeds. Oxidative stress-associated DiY crosslinking of α-syn therefore entails two opposing effects: (i) inhibition of aggregation by DiY-modified monomers and dimers, and (ii) stabilization of fibrillar aggregates against potential degradation mechanisms, which can lead to promotion of aggregation, especially in the presence of secondary nucleation. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  8. A setup for simultaneous measurement of infrared spectra and light scattering signals: Watching amyloid fibrils grow from intact proteins

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yang; Maurer, Jürgen; Roth, Andreas; Vogel, Vitali; Winter, Ernst; Mäntele, Werner, E-mail: maentele@biophysik.uni-frankfurt.de [Institut für Biophysik, Goethe-Universität Frankfurt am Main, Max-von Laue-Straße 1, D-60438 Frankfurt am Main (Germany)

    2014-08-15

    A setup for the simultaneous measurement of mid-infrared spectra and static light scattering is described that can be used for the analysis of the formation of nanoscale and microscopic aggregates from smaller molecules to biopolymers. It can be easily integrated into sample chambers of infrared spectrometers or combined with laser beams from tunable infrared lasers. Here, its use for the analysis of the formation of amyloid fibrils from intact proteins is demonstrated. The formation of amyloid fibrils or plaques from proteins is a widespread and pathogenetic relevant process, and a number of diseases are caused and correlated with the deposition of amyloid fibrils in cells and tissues. The molecular mechanisms of these transformations, however, are still unclear. We report here the simultaneous measurement of infrared spectra and static light scattering for the analysis of fibril formation from egg-white lysozyme. The transformation of the native form into non-native forms rich in β-sheet structure is measured by analysis of the amide I spectral region in the infrared spectra, which is sensitive for local structures. At the same time, light scattering signals at forward direction as well as the forward/backward ratio, which are sensitive for the number of scattering centers and their approximate sizes, respectively, are collected for the analysis of fibril growth. Thermodynamic and kinetic parameters as well as mechanistic information are deduced from the combination of the two complementary techniques.

  9. A setup for simultaneous measurement of infrared spectra and light scattering signals: Watching amyloid fibrils grow from intact proteins

    Science.gov (United States)

    Li, Yang; Maurer, Jürgen; Roth, Andreas; Vogel, Vitali; Winter, Ernst; Mäntele, Werner

    2014-08-01

    A setup for the simultaneous measurement of mid-infrared spectra and static light scattering is described that can be used for the analysis of the formation of nanoscale and microscopic aggregates from smaller molecules to biopolymers. It can be easily integrated into sample chambers of infrared spectrometers or combined with laser beams from tunable infrared lasers. Here, its use for the analysis of the formation of amyloid fibrils from intact proteins is demonstrated. The formation of amyloid fibrils or plaques from proteins is a widespread and pathogenetic relevant process, and a number of diseases are caused and correlated with the deposition of amyloid fibrils in cells and tissues. The molecular mechanisms of these transformations, however, are still unclear. We report here the simultaneous measurement of infrared spectra and static light scattering for the analysis of fibril formation from egg-white lysozyme. The transformation of the native form into non-native forms rich in β-sheet structure is measured by analysis of the amide I spectral region in the infrared spectra, which is sensitive for local structures. At the same time, light scattering signals at forward direction as well as the forward/backward ratio, which are sensitive for the number of scattering centers and their approximate sizes, respectively, are collected for the analysis of fibril growth. Thermodynamic and kinetic parameters as well as mechanistic information are deduced from the combination of the two complementary techniques.

  10. Atrial fibrillation and vascular disease-a bad combination

    DEFF Research Database (Denmark)

    Bjerring Olesen, Jonas; Gislason, Gunnar Hilmar; Torp-Pedersen, Christian

    2012-01-01

    This article provides an overview of (i) the risk of stroke associated with vascular disease (acute coronary syndromes and peripheral artery disease) in patients with atrial fibrillation, (ii) the frequent coexistence of vascular disease in patients with atrial fibrillation and, (iii...... fibrillation. Indeed, patients with atrial fibrillation often had coexisting vascular disease (around 18%), and the combination of the two diseases substantially increases the risk of future cardiovascular events. The increased risk associated with peripheral artery disease in atrial fibrillation is even more...... pronounced. Patients with atrial fibrillation and stable vascular disease should be treated with oral anticoagulation only, although when these patients present with acute coronary syndrome and/or undergo coronary stenting, concomitant treatment with antiplatelet drugs is indicated. To guide antithrombotic...

  11. Evidence of structurally continuous collagen fibrils in tendon

    DEFF Research Database (Denmark)

    Svensson, Rene B; Herchenhan, Andreas; Starborg, Tobias

    2017-01-01

    favor continuity. This study initially set out to trace the full length of individual fibrils in adult human tendons, using serial block face-scanning electron microscopy. But even with this advanced technique the required length could not be covered. Instead a statistical approach was used on a large...... volume of fibrils in shorter image stacks. Only a single end was observed after tracking 67.5 mm of combined fibril lengths, in support of fibril continuity. To shed more light on this observation, the full length of a short tendon (mouse stapedius, 125 μm) was investigated and continuity of individual...... fibrils was confirmed. In light of these results, possible mechanisms that could reconcile the opposing findings on fibril continuity are discussed. STATEMENT OF SIGNIFICANCE: Connective tissues hold all parts of the body together and are mostly constructed from thin threads of the protein collagen...

  12. Preparation of Amyloid Fibrils Seeded from Brain and Meninges.

    Science.gov (United States)

    Scherpelz, Kathryn P; Lu, Jun-Xia; Tycko, Robert; Meredith, Stephen C

    2016-01-01

    Seeding of amyloid fibrils into fresh solutions of the same peptide or protein in disaggregated form leads to the formation of replicate fibrils, with close structural similarity or identity to the original fibrillar seeds. Here we describe procedures for isolating fibrils composed mainly of β-amyloid (Aβ) from human brain and from leptomeninges, a source of cerebral blood vessels, for investigating Alzheimer's disease and cerebral amyloid angiopathy. We also describe methods for seeding isotopically labeled, disaggregated Aβ peptide solutions for study using solid-state NMR and other techniques. These methods should be applicable to other types of amyloid fibrils, to Aβ fibrils from mice or other species, tissues other than brain, and to some non-fibrillar aggregates. These procedures allow for the examination of authentic amyloid fibrils and other protein aggregates from biological tissues without the need for labeling the tissue.

  13. Endurance Sport Practice and Atrial Fibrillation

    OpenAIRE

    Calvo, Naiara; Mont, Lluis

    2010-01-01

    Atrial fibrillation (AF) is the most common cardiac rhythm disorder in clinical practice, with an estimated prevalence of 0.4% to 1% in the general population, increasing with age to 8% in those older than 80 years. The recognized risk factors for developing AF include age, hypertension, structural heart disease, diabetes mellitus, and hyperthyroidism. However, the etiology remains unclear in a significant number of patients younger than age 60 in whom no cardiovascular disease or any other k...

  14. Red Wine, Resveratrol and Atrial Fibrillation

    OpenAIRE

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as a...

  15. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Henrique Horta Veloso

    Full Text Available Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

  16. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Veloso Henrique Horta

    2003-01-01

    Full Text Available Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

  17. Atrial Fibrillation in Eight New World Camelids.

    Science.gov (United States)

    Bozorgmanesh, R; Magdesian, K G; Estell, K E; Stern, J A; Swain, E A; Griffiths, L G

    2016-01-01

    There is limited information on the incidence of clinical signs, concurrent illness and treatment options for atrial fibrillation (AF) in New World Camelids (NWC). Describe clinical signs and outcome of AF in NWC. Eight New World Camelids admitted with AF. A retrospective observational study of camelids diagnosed with AF based on characteristic findings on electrocardiogram (ECG). All animals had an irregularly irregular heart rhythm detected on physical examination and 4 cases had obtunded mentation on admission. Three camelids were diagnosed with AF secondary to oleander intoxication, 3 animals had underlying cardiovascular disease, 1 was diagnosed with lone AF and 1 had AF diagnosed on examination for a urethral obstruction. Five of eight animals survived to discharge and nonsurvivors consisted of animals which died or were euthanized as a result of cardiovascular disease (2/8) or extra-cardiac disease unrelated to the AF (1/8). Atrial fibrillation occurs in NWC in association with cardiovascular disease, extra-cardiac disease or as lone AF. Amiodarone and transthoracic cardioversion were attempted in one llama with lone AF, but were unsuccessful. Atrial fibrillation was recorded in 0.1% of admissions. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  18. Atrial fibrillation pearls and perils of management.

    Science.gov (United States)

    Kudenchuk, P J

    1996-01-01

    Atrial fibrillation, a common arrhythmia, is responsible for considerable cardiovascular morbidity. Its management demands more than antiarrhythmic therapy alone, but must address the causes and consequences of the arrhythmia. Although remediable causes are infrequently found, a thorough search for associated heart disease or its risk factors results in better-informed patient management. Controlling the ventricular response and protecting from thromboembolic complications are important initial goals of therapy and may include the administration of aspirin in younger, low-risk patients. Older patients and those with risk factors for systemic embolism are not adequately protected from stroke complications by aspirin therapy alone. It remains controversial whether all high-risk patients should receive warfarin and at what intensity. Whether and how sinus rhythm should be restored and maintained poses the greatest therapeutic controversy for atrial fibrillation. The mortal risk of antiarrhythmic therapy is substantially greater in patients with evidence of heart failure. In such persons, the risks and benefits of maintaining normal sinus rhythm with antiarrhythmic medications should be weighted carefully. A definitive cure for atrial fibrillation remains elusive, but promising surgical and catheter ablation therapies are being developed. PMID:8686300

  19. Electromechanical vortex filaments during cardiac fibrillation

    Science.gov (United States)

    Christoph, J.; Chebbok, M.; Richter, C.; Schröder-Schetelig, J.; Bittihn, P.; Stein, S.; Uzelac, I.; Fenton, F. H.; Hasenfuß, G.; Gilmour, R. F., Jr.; Luther, S.

    2018-03-01

    The self-organized dynamics of vortex-like rotating waves, which are also known as scroll waves, are the basis of the formation of complex spatiotemporal patterns in many excitable chemical and biological systems. In the heart, filament-like phase singularities that are associated with three-dimensional scroll waves are considered to be the organizing centres of life-threatening cardiac arrhythmias. The mechanisms that underlie the onset, maintenance and control of electromechanical turbulence in the heart are inherently three-dimensional phenomena. However, it has not previously been possible to visualize the three-dimensional spatiotemporal dynamics of scroll waves inside cardiac tissues. Here we show that three-dimensional mechanical scroll waves and filament-like phase singularities can be observed deep inside the contracting heart wall using high-resolution four-dimensional ultrasound-based strain imaging. We found that mechanical phase singularities co-exist with electrical phase singularities during cardiac fibrillation. We investigated the dynamics of electrical and mechanical phase singularities by simultaneously measuring the membrane potential, intracellular calcium concentration and mechanical contractions of the heart. We show that cardiac fibrillation can be characterized using the three-dimensional spatiotemporal dynamics of mechanical phase singularities, which arise inside the fibrillating contracting ventricular wall. We demonstrate that electrical and mechanical phase singularities show complex interactions and we characterize their dynamics in terms of trajectories, topological charge and lifetime. We anticipate that our findings will provide novel perspectives for non-invasive diagnostic imaging and therapeutic applications.

  20. Exercise-based cardiac rehabilitation for adults with atrial fibrillation

    DEFF Research Database (Denmark)

    Risom, Signe Stelling; Zwisler, Ann-Dorthe; Johansen, Pernille Palm

    2017-01-01

    BACKGROUND: Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria....... OBJECTIVES: To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, or have been treated for AF. SEARCH METHODS: We searched the following electronic databases; CENTRAL...... the benefits and harms of exercise-based cardiac rehabilitation for adults with atrial fibrillation on patient-relevant outcomes....

  1. Body weight gain after radioiodine therapy of hyperthyroidism; Koerpergewichtsentwicklung nach Radioiodtherapie einer Hyperthyreose

    Energy Technology Data Exchange (ETDEWEB)

    Scheidhauer, K.; Odatzidu, L.; Schicha, H. [Koeln Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Kiencke, P. [Koeln Univ. (DE). Inst. fuer Medizinische Statistik, Informatik und Epidemiologie (IMSIE)

    2002-02-01

    Aim: Analysis and follow up of body weight after radioiodine therapy (RITh) of hyperthyroidism, since excessive weight gain is a common complaint among these patients. Methods: Therapy and body weight related data of 100 consecutive RITh-patients were retrospectively analysed from the time before up to three years after RITh. All patients suffered from hyperthyroidism (Graves' disease or autonomy), but were adjusted to euthyroid levels after RITh. Patients' data were compared to a control group of 48 euthyroid patients out of the same ambulance and during the same time scale. Results: All patients (RITh and controls) gained weight over the time. There was no statistically significant difference in BMI development over three years between RITh-patients and controls (5.5% resp. 4.9% increase). In the first year after RITh, weight gain of the RITh patients was higher indeed, but lower in the follow up, resulting in the same range of weight gain after three years as the controls. Besides that women showed a slightly higher increase of BMI than men, and so did younger patients compared to elder as well as patients with overweight already before RITh. Conclusions: An initially distinct increase of body weight after RITh of hyperthyroidism is mainly a compensation of pretherapeutic weight loss due to hyperthyroidism. Presupposing adequate euthyroid adjustment of thyroid metabolism after therapy, RITh is not responsible for later weight gain and adipositas. (orig.) [German] Ziel: Untersuchung der Entwicklung des Koerpergewichtes nach {sup 131}I-Therapie einer Hyperthyreose, da der Radioiodtherapie (RITh) haeufig eine exzessive posttherapeutische Gewichtszunahme angelastet wird. Methoden: Retrospektiv wurden therapie- und koerpergewichtsbezogene Daten von 100 konsekutiven Patienten vor und bis drei Jahre nach RITh einer Hyperthyreose (Morbus Basedow oder funktionelle Autonomie) erfasst und mit denen einer euthyreoten Kontrollgruppe (n = 48) verglichen. Die

  2. Electrostatics promotes molecular crowding and selects the aggregation pathway in fibril-forming protein solutions

    International Nuclear Information System (INIS)

    Raccosta, S.; Martorana, V.; Manno, M.; Blanco, M.; Roberts, C.J.

    2016-01-01

    The role of intermolecular interaction in fibril-forming protein solutions and its relation with molecular conformation are crucial aspects for the control and inhibition of amyloid structures. Here, we study the fibril formation and the protein-protein interactions for two proteins at acidic ph, lysozyme and α-chymotrypsinogen. By using light scattering experiments and the Kirkwood-Buff integral approach, we show how concentration fluctuations are damped even at moderate protein concentrations by the dominant long-ranged electrostatic repulsion, which determines an effective crowded environment. In denaturing conditions, electrostatic repulsion keeps the monomeric solution in a thermodynamically metastable state, which is escaped through kinetically populated conformational sub-states. This explains how electrostatics acts as a gatekeeper in selecting a specific aggregation pathway.

  3. Anzeichen einer linearen dosis-effekt beziehung bei sehr kleinen bestrahlungsdosen

    CERN Document Server

    Diehl, I.

    1980-01-01

    Zur Aufstellung einer Strahlungsdosis - Effekt - Kurve bei kleinen Dosen wurde der Mikrokerntest verwendet, da er relativ einfach und gleich- zeitig sehr empfindlich ist. Die Bohne Vicia Faba (Fillbasket) wurde mit 60Co Gammastrahlen und mit hochenergetischen Neutronen bestrahlt. Die Neutronen wurden von 600 MeV Protonen, die auf ein Be—Target auftrafen produziert und unter einem Winkel von 0 Grad extrahiert. Informationen fiber Dosimetrie und Eigenschaften der verwandeten Strahlung wurder bereits an anderer Stelle beschriebenl) des gleichen auch Einzelheiten fiber die Aufzucht der BORE Vicia Fabaz). Nach der Bestrahlung wurden jeweils 5 Bohnen zu bestimmten Zeitpunkten fixiert und danach die Prfiparate herge— stellt. Pro Préparat wurden 1000 Zellen ausgewertet.

  4. [The birth of metapsychology. On the current interpretation of "Entwurf einer Psychologie" (1895)].

    Science.gov (United States)

    Schmidt-Hellerau, C

    1995-12-01

    The general attitude towards Entwurf einer Psychologie (1895) is to reckon it among Freud's pre-analytic writings, i.e. that part of his work later more or less disowned by the author. Schmidt-Hellerau challenges this assessment by Freud and many of his successors, demonstrating that the Entwurf can legitimately be regarded as a meta-theory resolving - or skirting- the old classification problem of whether psychoanalysis is a science or an art by connecting the hitherto dissociated spheres of soma and psyche and conceptualizing of physiological and psychological processes. See thus, the Entwurf reveals itself as a theoretical document of astonishing modernity and undiminished relevance in that it records Freud's ambitious attempt to overcome the mind-body schism and the divide between neurophysiology and psychology. And it is precisely this problem, the author contends, which Freud's later metapsychology--and the controversies it has aroused--revolves around.

  5. Objektverfolgung bei einer vollständigen Fahrzeugumfeldüberwachung mittels Radar

    Science.gov (United States)

    Schuster, M.; Pech, T.; Reuter, J.; Wanielik, G.

    2014-11-01

    Für modernste Fahrerassistenzsysteme ist zunehmend eine vollständige Rundumüberwachung des fließenden Verkehrs erforderlich. In diesem Artikel wird ein Ansatz zur Überwachung des gesamten umliegenden Verkehrs mittels Radarsystemen präsentiert. Hierfür wurde ein Versuchsfahrzeug mit insgesamt sechs Radarsensoren ausgerüstet, um eine möglichst hohe Umfeld-Überwachung zu ermöglichen. Für diese Konfiguration wird ein auf GPDA basierendes Trackingsystem vorgestellt. Es wird auf das Problem ausgedehnter Ziele eingegangen, welches auftritt wenn sich ein Fremdfahrzeug neben dem Versuchsfahrzeug befindet, da hier Reflektionen von verschiedenen Reflektionszentren des Ziels aufgefangen werden. Dieser Effekt wird ausgenutzt, um mittels einer Track-zu-Track Fusion eine Längenschätzung des vorbeifahrenden Fahrzeugs zu ermöglichen.

  6. Zu einer inhaltsorientierten Theorie des Lernens und Lehrens der biologischen Evolution

    Science.gov (United States)

    Wallin, Anita

    Der Zweck dieser Studie (zwecks Überblick siehe dazu Abb. 9.1) war zu untersuchen, wie die Schüler der Sekundarstufe II ein Verständnis von der Theorie der biologischen Evolution entwickeln. Vom Ausgangspunkt "Vorurteile der Schüler“ ausgehend wurden Unterrichtssequenzen entwickelt und drei verschiedene Lernexperimente in einem zyklischen Prozess durchgeführt. Das Wissen der Schüler wurde vor, während und nach den Unterrichtssequenzen mit Hilfe von schriftlichen Tests, Interviews und Diskussionsrunden in kleinen Gruppen abgefragt. Etwa 80 % der Schüler hatten vor dem Unterricht alternative Vorstellungen von Evolution, und in dem Nachfolgetest erreichten circa 75 % ein wissenschaftliches Niveau. Die Argumentation der Schüler in den verschiedenen Tests wurde sorgfältig unter Rücksichtnahme auf Vorurteile, der konzeptionellen Struktur der Theorie der Evolution und den Zielen des Unterrichts analysiert. Daraus konnten Einsichten in solche Anforderungen an Lehren und Lernen gewonnen werden, die Herausforderungen an Schüler und Lehrer darstellen, wenn sie anfangen, evolutionäre Biologie zu lernen oder zu lehren. Ein wichtiges Ergebnis war, dass das Verständnis existierender Variation in einer Population der Schlüssel zum Verständnis von natürlicher Selektion ist. Die Ergebnisse sind in einer inhaltsorientierten Theorie zusammengefasst, welche aus drei verschiedenen Aspekten besteht: 1) den inhaltsspezifischen Aspekten, die einzigartig für jedes wissenschaftliche Feld sind; 2) den Aspekten, die die Natur der Wissenschaft betreffen; und 3) den allgemeinen Aspekten. Diese Theorie kann in neuen Experimenten getestet und weiter entwickelt werden.

  7. Influence of hormone substitution therapy on postmenopausal uterus; Einfluss einer Hormonsubstitution auf den postmenopausalen Uterus

    Energy Technology Data Exchange (ETDEWEB)

    Otte, A.; Ruedisueli, A.; Goetze, M.; Leibundgut, U.; Mueller-Brand, J. [Inst. fuer Nuklearmedizin, Kantonsspital, Universitaetskliniken, Basel (Switzerland); Nitzsche, E.U. [Abt. Nuklearmedizin, Radiologische Universitaetsklinik, Freiburg (Germany)

    1997-12-01

    In a 58-year-old postmenopausal woman blood flow and blood pool images of bone scintigraphy showed a focus of increased activity in the right pelvic region. Computed tomography and ultrasound exhibited no abnormalities in the abdomen; especially the uterus and ovaries were normal. Careful anamnestic evaluation revealed that the patient received a long-term peroral estrogen/gestagen replacement therapy for the prevention of osteoporosis, but did not have menstruation-like bleedings for the last twelve months of therapy. At time of admission, the patient was on day 25 of hormone replacement therapy, and the uterus wash, therefore, in a premenstrual stage. Hence, despite cessation of bleedings in postmenopausal women, one should think of hormone replacement therapy as an explanation for vascular pelvic tumors seen by the first two phases of bone scintigraphy, before further diagnostic steps are undertaken. (orig.) [Deutsch] Bei der Skelettszintigraphie einer 58jaehrigen postmenopausalen Frau erkannte man in der Perfusions- und Blood-pool-Phase einen unklaren Fokus erhoehter Aktivitaet im rechten Becken. Computertomographie und Sonographie des Abdomens, insbesondere des Uterus und der Ovarien, waren unauffaellig. Nach eingehender anamnestischer Befragung stellte sich heraus, dass die Patientin unter einer mehrjaehrigen peroralen Oestrogen-/Gestagen-Hormonsubstitutionstherapie zur Osteoporose-Prophylaxe stand, jedoch seit den letzten zwoelf Monaten der Therapie ueber keine menstruationsaehnlichen Abbruchblutungen mehr berichten konnte. Bei ihrer Zuweisung befand sich die Patientin am 25. Tag der Hormonsubstitutionstherapie und ihr Uterus somit in einem praemenstruellen Stadium. Trotz Ausbleibens der Blutung bei postmenopausalen Frauen sollte somit an die Moeglichkeit der Hormonsubstitution gedacht und danach gefragt werden, wenn in den ersten beiden Phasen der Skelettszintigraphie eine unklare, gut vaskularisierte Struktur im kleinen Becken gefunden wird, bevor weitere

  8. Does Myocardial Infarction Beget Atrial Fibrillation and Atrial Fibrillation Beget Myocardial Infarction?

    NARCIS (Netherlands)

    Vermond, Rob A.; Van Gelder, Isabelle C.; Crijns, Harry J.; Rienstra, Michiel

    2015-01-01

    Atrial fibrillation (AF) affects millions of people worldwide.(1) It is already known several decades that AF is not a benign condition, and it's associated with a 5-fold increased risk of stroke, 3-fold increased risk of heart failure, and doubling of risk of dementia and death.(2-4) Myocardial

  9. Family history of atrial fibrillation is associated with earlier-onset and more symptomatic atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Fosbøl, Emil Loldrup; Kim, Sunghee

    2016-01-01

    BACKGROUND: We addressed whether patients with a family history of atrial fibrillation (AF) were diagnosed as having AF earlier in life, were more symptomatic, and had worse outcomes compared with those without a family history of AF. METHODS: Using the ORBIT-AF, we compared symptoms and disease...

  10. From Fibril Formation to Fibril Properties and Rheology of Food Materials

    NARCIS (Netherlands)

    Linden, van der E.; Venema, P.

    2013-01-01

    For control and design of food properties it is important to understand how molecules and their interactions give rise to formation of microstructures and resulting rheological properties. This will be illustrated by discussing the formation and properties of fibrils in aqueous and non-aqueous

  11. La fibrillation auriculaire chez le noir Africain: Aspects ...

    African Journals Online (AJOL)

    In this retrospective work realized during two years (1st january 2002 to 31 december 2003), relative to 300 cases hospitalized at the Cardiology Institute of Abidjan, the authors have studied the epidemiologic, etiologic and prognosis factors of black african atrial fibrillation in hospital cercle. The atrial fibrillation was the most ...

  12. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events...... in high-risk permanent atrial fibrillation....

  13. Relevance of Electrical Remodeling in Human Atrial Fibrillation Results of the Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial Mechanisms of Atrial Fibrillation Study

    NARCIS (Netherlands)

    Healey, Jeff S.; Israel, Carsten W.; Connolly, Stuart J.; Hohnloser, Stefan H.; Nair, Girish M.; Divakaramenon, Syamkumar; Capucci, Alessandro; Van Gelder, Isabelle C.; Lau, Chu-Pak; Gold, Michael R.; Carlson, Mark; Themeles, Ellison; Morillo, Carlos A.

    Background-In animal models of atrial fibrillation (AF), changes in atrial electrophysiological properties are associated with the development of AF. Their relevance to human AF is unclear. Methods and Results-The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the

  14. The safety of flecainide treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Almroth, H; Andersson, Torben Bech; Fengsrud, E

    2011-01-01

    To assess the safety of long-term treatment with flecainide in patients with atrial fibrillation (AF), particularly with regard to sudden cardiac death (SCD) and proarrhythmic events.......To assess the safety of long-term treatment with flecainide in patients with atrial fibrillation (AF), particularly with regard to sudden cardiac death (SCD) and proarrhythmic events....

  15. Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Helen P McWilliams-Koeppen

    Full Text Available Light chain (AL amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(PH-dependent oxidoreductase, without causing significant cell death. The presence of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. These data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.

  16. Atrial fibrillation and bleeding complication - risk factors and risk marker

    NARCIS (Netherlands)

    Breithardt, G.; Ravens, U.; Kirchhof, P.; van Gelder, I. C.

    2012-01-01

    The development of atrial fibrillation (AF) is closely linked to risk factors like hypertension and heart failure, diabetes mellitus, myocardial infarction and valvular heart disease. These factors partly overlap with those which determine the progression of atrial fibrillation and the incidence of

  17. Effect of Stirring and Seeding on Whey Protein Fibril Formation

    NARCIS (Netherlands)

    Bolder, S.G.; Sagis, L.M.C.; Venema, P.; Linden, van der E.

    2007-01-01

    The effect of stirring and seeding on the formation of fibrils in whey protein isolate (WPI) solutions was studied. More fibrils of a similar length are formed when WPI is stirred during heating at pH 2 and 80 C compared to samples that were heated at rest. Addition of seeds did not show an

  18. Aggregation properties of a short peptide that mediates amyloid fibril ...

    Indian Academy of Sciences (India)

    Short peptides have been identified from amyloidogenic proteins that form amyloid fibrils in isolation. The ... proteins. These peptide fibrils have the conformational features of β-structure that .... water and immediately deposited on freshly cleaved surface of mica .... with the peptide via electrostatic interactions. NaCl would.

  19. Polymorphism complexity and handedness inversion in serum albumin amyloid fibrils.

    Science.gov (United States)

    Usov, Ivan; Adamcik, Jozef; Mezzenga, Raffaele

    2013-12-23

    Protein-based amyloid fibrils can show a great variety of polymorphic structures within the same protein precursor, although the origins of these structural homologues remain poorly understood. In this work we investigate the fibrillation of bovine serum albumin--a model globular protein--and we follow the polymorphic evolution by a statistical analysis of high-resolution atomic force microscopy images, complemented, at larger length scales, by concepts based on polymer physics formalism. We identify six distinct classes of coexisting amyloid fibrils, including flexible left-handed twisted ribbons, rigid right-handed helical ribbons and nanotubes. We show that the rigid fibrils originate from flexible fibrils through two diverse polymorphic transitions, first, via a single-fibril transformation when the flexible left-handed twisted ribbons turn into the helical left-handed ribbons, to finally evolve into nanotube-like structures, and second, via a double-fibril transformation when two flexible left-handed twisted ribbons wind together resulting in a right-handed twisted ribbon, followed by a rigid right-handed helical ribbon polymorphic conformation. Hence, the change in handedness occurs with an increase in the level of the fibril's structural organization.

  20. Genetics of Atrial Fibrillation and Possible Implications for Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Robin Lemmens

    2011-01-01

    Full Text Available Atrial fibrillation is the most common cardiac arrhythmia mainly caused by valvular, ischemic, hypertensive, and myopathic heart disease. Atrial fibrillation can occur in families suggesting a genetic background especially in younger subjects. Additionally recent studies have identified common genetic variants to be associated with atrial fibrillation in the general population. This cardiac arrhythmia has important public health implications because of its main complications: congestive heart failure and ischemic stroke. Since atrial fibrillation can result in ischemic stroke, one might assume that genetic determinants of this cardiac arrhythmia are also implicated in cerebrovascular disease. Ischemic stroke is a multifactorial, complex disease where multiple environmental and genetic factors interact. Whether genetic variants associated with a risk factor for ischemic stroke also increase the risk of a particular vascular endpoint still needs to be confirmed in many cases. Here we review the current knowledge on the genetic background of atrial fibrillation and the consequences for cerebrovascular disease.

  1. 'Integration'

    DEFF Research Database (Denmark)

    Olwig, Karen Fog

    2011-01-01

    , while the countries have adopted disparate policies and ideologies, differences in the actual treatment and attitudes towards immigrants and refugees in everyday life are less clear, due to parallel integration programmes based on strong similarities in the welfare systems and in cultural notions...... of equality in the three societies. Finally, it shows that family relations play a central role in immigrants’ and refugees’ establishment of a new life in the receiving societies, even though the welfare society takes on many of the social and economic functions of the family....

  2. NASA's First Atrial Fibrillation Case - Deke Slayton

    Science.gov (United States)

    Tarver, William J.

    2010-01-01

    Concerns about heart dysrhythmia have been present since the earliest days of the US manned space program. While information about an astronaut's health is general kept private, one of the original seven American astronaut's health status was played out in a very public forum. Donald "Deke" Slayton was removed from the second manned space flight when it was discovered he had idiopathic atrial fibrillation. Referencing the original medical documents, details of how this was discovered and managed from the medical perspective will be reviewed. This is NASA's first heart dysrhythmia case in an astronaut and it proves quite interesting when placed in historic perspective.

  3. Current approaches in atrial fibrillation treatment

    Directory of Open Access Journals (Sweden)

    Cenk Sarı

    2014-09-01

    Full Text Available Atrial fibrillation (AF is the most common sustained arrhythmia encountered in clinical practice. Its incidence increases with age. AF is classified into subtypes according to the duration and/or able to provide sinus rhytym. İnitially, patients should be evaluated for rhythm or rate control for appropriate treatment. Second stage of strategy aimed to investigate the feasibility of anticoagulation therapy. Recently, due to the progress made in treatment with rhythm control and anticoagulation therapy, either American or European guidelines have been renovated. These developments have taken place in the newly published guide. In this article, the current change in the management of AF is discussed.

  4. The contrasting effect of macromolecular crowding on amyloid fibril formation.

    Directory of Open Access Journals (Sweden)

    Qian Ma

    Full Text Available Amyloid fibrils associated with neurodegenerative diseases can be considered biologically relevant failures of cellular quality control mechanisms. It is known that in vivo human Tau protein, human prion protein, and human copper, zinc superoxide dismutase (SOD1 have the tendency to form fibril deposits in a variety of tissues and they are associated with different neurodegenerative diseases, while rabbit prion protein and hen egg white lysozyme do not readily form fibrils and are unlikely to cause neurodegenerative diseases. In this study, we have investigated the contrasting effect of macromolecular crowding on fibril formation of different proteins.As revealed by assays based on thioflavin T binding and turbidity, human Tau fragments, when phosphorylated by glycogen synthase kinase-3β, do not form filaments in the absence of a crowding agent but do form fibrils in the presence of a crowding agent, and the presence of a strong crowding agent dramatically promotes amyloid fibril formation of human prion protein and its two pathogenic mutants E196K and D178N. Such an enhancing effect of macromolecular crowding on fibril formation is also observed for a pathological human SOD1 mutant A4V. On the other hand, rabbit prion protein and hen lysozyme do not form amyloid fibrils when a crowding agent at 300 g/l is used but do form fibrils in the absence of a crowding agent. Furthermore, aggregation of these two proteins is remarkably inhibited by Ficoll 70 and dextran 70 at 200 g/l.We suggest that proteins associated with neurodegenerative diseases are more likely to form amyloid fibrils under crowded conditions than in dilute solutions. By contrast, some of the proteins that are not neurodegenerative disease-associated are unlikely to misfold in crowded physiological environments. A possible explanation for the contrasting effect of macromolecular crowding on these two sets of proteins (amyloidogenic proteins and non-amyloidogenic proteins has been

  5. Increased amount of atrial fibrosis in patients with atrial fibrillation secondary to mitral valve disease

    NARCIS (Netherlands)

    Geuzebroek, Guillaume S. C.; van Amersfoorth, Shirley C. M.; Hoogendijk, Mark G.; Kelder, Johannes C.; van Hemel, Norbert M.; de Bakker, Jacques M. T.; Coronel, Ruben

    2012-01-01

    Objective: Atrial fibrosis is related to atrial fibrillation but may differ in patients with mitral valve disease or lone atrial fibrillation. Therefore, we studied atrial fibrosis in patients with atrial fibrillation + mitral valve disease or with lone atrial fibrillation and compared it with

  6. Atrial Fibrillation: When the heart is not in rhythm | NIH MedlinePlus the Magazine

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: When the heart is not in rhythm Past ... show, Deal With It . Photo: TBS/Deal Understanding Atrial Fibrillation Atrial fibrillation (AFib) is the most common type ...

  7. Das Portfolio als Beitrag zur Reflexion persönlicher Kompetenzentwicklung in der Religions-/PädagogInnenbildung. Chancen einer neuen Lern- und Bewertungskultur - am Beispiel einer Fallstudie

    Directory of Open Access Journals (Sweden)

    Alexander van Dellen

    2013-10-01

    Full Text Available ”Competence orientation” in pedagogy education constitutes a central point within the draft laws formulated on the 12th of June 2013. These see the use of portfolios as playing a crucial part of religious instruction education. This is based on the expectation that portfolios act as continuous and helpful companions throughout the various educational phases and therefore benefit students’ reflections on individual competence development. Portfolios allow effective measures towards personal development as a professional educator to be taken. The format at hand, which was conceived as a case study at the Institute for Practical Theology (department catechetics, religious education studies and religious didactics at the Faculty of Catholic Theology at the University of Innsbruck, is intended to be used as a basis for a discussion on the benefits of a continuous portfolio as a reflection tool for students’ personal competence development. The first step illustrates the genesis and structure of the portfolio concept (2, so that the second step can then outline the potentials held by this new culture of using portfolios as learning and assessment tools in religious instruction education (3. In den vom österreichischen Parlament am 12. Juni 2013 beschlossenen Gesetzesentwürfen zur zukünftigen PädagogInnenbildung stellt die Kompetenzorientierung einen Kernpunkt dar. In diesem Zusammenhang wird in der Ausbildung von Religions-/PädagogInnen der Einsatz von Portfolios verstärkt eine zentrale Rolle spielen. Damit ist die Hoffnung verbunden, dass das Portfolio als Kontinuum in den unterschiedlichen Phasen der Religions-/PädagogInnenbildung für Studierende ein hilfreiches Instrument für die Reflexion ihrer individuellen Kompetenzentwicklung bildet. Somit kann eine wirksame Maßnahme der persönlichen Entwicklung in der Professionalisierung für den Lehrberuf gesetzt werden. In den vorliegenden Ausführungen soll auf der Grundlage einer

  8. Patientenakzeptanz und Verträglichkeit von Risedronat zur Osteoporosetherapie - Ergebnisse einer Phase IV-Studie

    Directory of Open Access Journals (Sweden)

    Pusch HH

    2001-01-01

    Full Text Available Anwendungsbeobachtungen (Phase IV-Studien haben nach den erfolgreich absolvierten klinischen Prüfungen (Phase III den Zweck, die Verträglichkeit, Sicherheit, Compliance und Akzeptanz eines Präparates in der täglichen praktischen Medizin zu erfassen und auszuwerten. Eine AWB ist prospektiv aufgebaut. Die 1121 in dieser Studie erfaßten Patienten stellen ein solides Fundament für die statistische Aufarbeitung der erhobenen Daten dar. Die Ergebnisse zu den Themen Patientendaten, Diagnosestellung, Risikofaktoren, Frakturen und Mobilität zeigen deutlich, daß hier ein spezielles Patientengut vorliegt: Der Patient mit Osteoporose mit den typischen alterskorrelierten Begleiterkrankungen. Die Osteoporose verläuft, so lange keine Frakturen eintreten, praktisch schmerzfrei - ein Grund, warum diese Erkrankung so oft und so lange ignoriert wird. Begleitende Beschwerden gehen nach der derzeitigen Lehrmeinung stets auf degenerative oder entzündlich-rheumatische Prozesse am Bewegungsapparat zurück. Aus diesem Blickwinkel bieten die Ergebnisse dieser Studie eine Überraschung: Die im Bereich der Wirbelsäule beobachtete und statistisch hochsignifikante Schmerzlinderung. Sie läßt sich jedoch mit der Hemmung des Knochenabbaues durch Risedronat alleine nicht befriedigend erklären. Möglicherweise liegen hier andere, bisher unbekannte pharmakologische Effekte dieser Substanz vor. Zusätzliche Hinweise ergeben sich daraus, daß beim Mb. Paget ähnliche Wirkungen auf die Begleitschmerzen bei Bisphosphonatbehandlung berichtet wurden. Die analgetische Wirkung von Calcitonin ist bekannt, sie beruht auf einer zentralnervösen Wirkung, ebenso wie auf der Hemmung der Freisetzung von freien Kalzium-Ionen, die als Schmerzmediator angesehen werden, aus dem Knochen. Vielleicht liegen hier vergleichbare Effekte vor, die in den Phase II und III Studien nicht zutage treten konnten. Diese überraschenden Ergebnisse sollten Anlaß für weitere Forschungen sein. Die

  9. Die Veränderung der Grenzen in einer transnationalen Gebietskörperschaft

    Directory of Open Access Journals (Sweden)

    Karen Denni

    2009-12-01

    Full Text Available L’objet de notre article est de mettre en lumière la multiplicité des frontières qui structurent la zone frontalière de Strasbourg-Ortenau. Au cours de son histoire, la frontière francoallemande a considérablement évolué. Zone conflictuelle de rupture comme lors de la guerre franco-allemande de 1870-1871, elle représente désormais un espace pacifié et intégré dans un ensemble politique européen plus large. La convention pour la création d’un eurodistrict franco-allemand conclue en 2005 prévoit même le dépassement des frontières politiques et administratives en visant la fusion de ces deux collectivités contiguës séparées par le Rhin et concourt, grâce à la proximité géographique et organisationnelle que permet la petite structure ainsi créée, à faciliter l’articulation entre l’échelle locale et l’échelle globale. Mais, malgré cette convention qui a intensifié la coopération transfrontalière, ce projet suscite encore de nombreuses interrogations aux plans juridique, politique et social. En outre, les citoyens français et allemands de la zone du Rhin supérieur restent finalement assez peu informés de l’importante progression que connaît la coopération transfrontalière dans ce secteur et n’y voient que peu d’avantages. Une plus large implication des citoyens à ce projet semble indispensable afin que ceux-ci apportent créativité et dynamisme à la construction d’une nouvelle entité politique dans laquelle il leur sera alors possible de s’identifier. Un long chemin reste donc à parcourir avant que le Rhin cesse de représenter une frontière entre la France et l’Allemagne et se transforme en un véritable trait d’union entre ces deux pays.Ziel dieses Artikels ist es, die vielfältigen Aspekte der Grenzen darzulegen, die den Grenzraum Straßburg-Kehl strukturieren. Im Laufe ihrer Geschichte hat die deutsch-französische Grenze einen großen Wandel vollzogen, von einer

  10. Organized Atrial Tachycardias after Atrial Fibrillation Ablation

    Science.gov (United States)

    Castrejón-Castrejón, Sergio; Ortega, Marta; Pérez-Silva, Armando; Doiny, David; Estrada, Alejandro; Filgueiras, David; López-Sendón, José L.; Merino, José L.

    2011-01-01

    The efficacy of catheter-based ablation techniques to treat atrial fibrillation is limited not only by recurrences of this arrhythmia but also, and not less importantly, by new-onset organized atrial tachycardias. The incidence of such tachycardias depends on the type and duration of the baseline atrial fibrillation and specially on the ablation technique which was used during the index procedure. It has been repeatedly reported that the more extensive the left atrial surface ablated, the higher the incidence of organized atrial tachycardias. The exact origin of the pathologic substrate of these trachycardias is not fully understood and may result from the interaction between preexistent regions with abnormal electrical properties and the new ones resultant from radiofrequency delivery. From a clinical point of view these atrial tachycardias tend to remit after a variable time but in some cases are responsible for significant symptoms. A precise knowledge of the most frequent types of these arrhythmias, of their mechanisms and components is necessary for a thorough electrophysiologic characterization if a new ablation procedure is required. PMID:21941669

  11. Analysis of an accident involving a battery of hydrogen flasks; Analyse eines Unfalls mit einer Flaschenbatterieanlage fuer Wasserstoff

    Energy Technology Data Exchange (ETDEWEB)

    Lietze, D. [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany)

    2000-09-01

    When a hydrogen storage flask battery was used again after an outage period, a small section of the high-pressure collecting main burst. Luckily, the leaking hydrogen did not ignite and there were no fires or explosions causing secondary damage. The cause of failure was identified on the basis of extensive knowledge on pipeline loads shortly after detonative reactions. [German] Nach einer laengeren Pause kam es bei der Inbetriebnahme einer Wasserstoff-Flaschenbatterieanlage zum Bersten eines kleinen Teilstuecks der Hochdrucksammelleitung. Gluecklicherweise gab es keine Zuendung des an dieser Bruchstelle ausstroemenden Wasserstoffs und damit auch keine weiteren Sekundaerschaeden durch einen Brand bzw. durch eine Raumexplosion. Aufgrund der bei umfangreichen Untersuchungen ueber die Beanspruchung von Rohrleitungen bei detonativ verlaufenden Reaktionen gemachten Erfahrungen konnte die Ursache fuer diesen Schadensfall ermittelt werden. (orig.)

  12. Die Kraft einer phänomenologischen Haltung. Reflexionen aus der Praxis des Religionsunterrichtes.

    Directory of Open Access Journals (Sweden)

    Joachim Hawel

    2014-07-01

    Full Text Available ENGLISH: Initially the terms ‚phenomenological‘ and ‚phenomenological attitude‘ respectively will be explicated. The phenomenological attitude is an attitude of mental and spiritual looking, which distinguishes between ‚feeling first‘ and ‚thinking later‘, it seeks to avoid, that, when problems in religious education class present themselves, by a rash assessment ‚That’s how it is‘ the personhood of the student and the personhood of the teacher are neglected. This attitude has several prerequisites, above all has to be the conscious decision for this attitude, which must be practiced and reflected a whole professional life. In the main part of the article six elements of a phenomenological attitude will be explained, the last of which relates to the ‚phenomenology of life‘ by Michel Henry, which points out, that the most essential part, namely life itself, is beyond visibility, which has drastic consequences for religious education – or any education for that matter. The ‚lifelong practicing‘ of this attitude also requires an extra occupational continuous development of the personality, which can also serve as burnout prophylaxis. DEUTSCH: Zunächst werden die Begriffe ‚phänomenologisch‘ bzw. ‚phänomenologische Haltung‘ expliziert. Die phänomenologische Haltung ist eine Haltung geistigen Schauens, die zwischen ‚Vor-Fühlen‘ und ‚Nach-Denken‘ unterscheidet, sie versucht zu vermeiden, dass man bei Problemen im Religionsunterricht durch die vorschnelle Feststellung ‚So ist es‘ das Person-Sein der SchülerInnen und das Person-Sein der Lehrenden außer Acht lässt. Diese Haltung hat mehrere Voraussetzungen, zuallererst bedarf es der bewussten Entscheidung für diese Haltung, die ein Berufsleben lang eingeübt bzw. reflektiert werden muss. Sechs Elemente einer phänomenologischen Haltung werden im Hauptteil des Artikels ausgeführt, das letzte Element bezieht sich auf die

  13. Fibril formation from pea protein and subsequent gel formation.

    Science.gov (United States)

    Munialo, Claire Darizu; Martin, Anneke H; van der Linden, Erik; de Jongh, Harmen H J

    2014-03-19

    The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20 h at pH 2.0. Following heating of pea proteins, it was observed that all of the proteins were hydrolyzed into peptides and that 50% of these peptides were assembled into fibrils. Changes on a structural level in pea proteins were studied using circular dichroism, transmission electron microscopy, and particle size analysis. During the fibril assembly process, an increase in aggregate size was observed, which coincided with an increase in thioflavin T binding, indicating the presence of β-sheet aggregates. Fibrils made using pea proteins were more branched and curly. Gel formation of preformed fibrils was induced by slow acidification from pH 7.0 to a final pH of around pH 5.0. The ability of pea protein-based fibrillar gels to fracture during an amplitude sweep was comparable to those of soy protein and whey protein-based fibrillar gels, although gels prepared from fibrils made using pea protein and soy protein were weaker than those of whey protein. The findings show that fibrils can be prepared from pea protein, which can be incorporated into protein-based fibrillar gels.

  14. Sequence dependent aggregation of peptides and fibril formation

    Science.gov (United States)

    Hung, Nguyen Ba; Le, Duy-Manh; Hoang, Trinh X.

    2017-09-01

    Deciphering the links between amino acid sequence and amyloid fibril formation is key for understanding protein misfolding diseases. Here we use Monte Carlo simulations to study the aggregation of short peptides in a coarse-grained model with hydrophobic-polar (HP) amino acid sequences and correlated side chain orientations for hydrophobic contacts. A significant heterogeneity is observed in the aggregate structures and in the thermodynamics of aggregation for systems of different HP sequences and different numbers of peptides. Fibril-like ordered aggregates are found for several sequences that contain the common HPH pattern, while other sequences may form helix bundles or disordered aggregates. A wide variation of the aggregation transition temperatures among sequences, even among those of the same hydrophobic fraction, indicates that not all sequences undergo aggregation at a presumable physiological temperature. The transition is found to be the most cooperative for sequences forming fibril-like structures. For a fibril-prone sequence, it is shown that fibril formation follows the nucleation and growth mechanism. Interestingly, a binary mixture of peptides of an aggregation-prone and a non-aggregation-prone sequence shows the association and conversion of the latter to the fibrillar structure. Our study highlights the role of a sequence in selecting fibril-like aggregates and also the impact of a structural template on fibril formation by peptides of unrelated sequences.

  15. Replica Exchange Simulations of the Thermodynamics of Aβ Fibril Growth

    Science.gov (United States)

    Takeda, Takako; Klimov, Dmitri K.

    2009-01-01

    Abstract Replica exchange molecular dynamics and an all-atom implicit solvent model are used to probe the thermodynamics of deposition of Alzheimer's Aβ monomers on preformed amyloid fibrils. Consistent with the experiments, two deposition stages have been identified. The docking stage occurs over a wide temperature range, starting with the formation of the first peptide-fibril interactions at 500 K. Docking is completed when a peptide fully adsorbs on the fibril edge at the temperature of 380 K. The docking transition appears to be continuous, and occurs without free energy barriers or intermediates. During docking, incoming Aβ monomer adopts a disordered structure on the fibril edge. The locking stage occurs at the temperature of ≈360 K and is characterized by the rugged free energy landscape. Locking takes place when incoming Aβ peptide forms a parallel β-sheet structure on the fibril edge. Because the β-sheets formed by locked Aβ peptides are typically off-registry, the structure of the locked phase differs from the structure of the fibril interior. The study also reports that binding affinities of two distinct fibril edges with respect to incoming Aβ peptides are different. The peptides bound to the concave edge have significantly lower free energy compared to those bound on the convex edge. Comparison with the available experimental data is discussed. PMID:19167295

  16. Die Erforschung kollektiver und individueller Dynamik – Zu einer historisch und prozess-soziologisch orientierten interpretativen Sozialforschung

    Directory of Open Access Journals (Sweden)

    Gabriele Rosenthal

    2016-04-01

    Full Text Available In diesem Beitrag konzentriere ich mich auf die Vorteile einer konsequent durchgeführten interpretativen oder rekonstruktiven Sozialforschung gegenüber anderen qualitativen Verfahren und verdeutliche, inwiefern wir diese Vorteile noch konsequenter verfolgen können als bisher. Dabei stellen sich die folgenden Fragen: Was können wir mit wenigen, aber aufwendigen Fallrekonstruktionen mit dem Ziel einer "theoretischen Verallgemeinerung" am Einzelfall im Unterschied zu qualitativen Verfahren mit umfangreichen Stichproben leisten, die eher eine numerische oder quantitative Verallgemeinerung zum Ziel haben? Inwiefern kommen wir damit überhaupt zu "allgemeinen" Aussagen über die soziale (kollektive und individuelle Wirklichkeit, über eine bestimmte Gruppierung, Organisation oder Ortsgemeinde, einen kollektiver Konflikt, ein bestimmtes Milieu oder soziales Netzwerk? Bei der Behandlung dieser Fragen geht es mir vor allem um ein Plädoyer für eine methodisch stärker historisch und prozess-soziologisch orientierte interpretative Sozialforschung. M.E. liegen in einer konsequenten Rekonstruktion der Verläufe und Wandlungsprozesse von einzelnen "Fällen" und ihrer Verflechtungen mit anderen "Fällen" die Chancen für eine wirklich empirisch geerdete Theorieentwicklung. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1602139

  17. Proinsulin C-peptide interferes with insulin fibril formation

    International Nuclear Information System (INIS)

    Landreh, Michael; Stukenborg, Jan-Bernd; Willander, Hanna; Söder, Olle; Johansson, Jan; Jörnvall, Hans

    2012-01-01

    Highlights: ► Insulin and C-peptide can interact under insulin fibril forming conditions. ► C-peptide is incorporated into insulin aggregates and alters aggregation lag time. ► C-peptide changes insulin fibril morphology and affects backbone accessibility. ► C-peptide may be a regulator of fibril formation by β-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic β-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

  18. Proinsulin C-peptide interferes with insulin fibril formation

    Energy Technology Data Exchange (ETDEWEB)

    Landreh, Michael [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden); Stukenborg, Jan-Bernd [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Willander, Hanna [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Soeder, Olle [Department of Women' s and Children' s Health, Astrid Lindgren Children' s Hospital, Pediatric Endocrinology Unit, Karolinska Institutet and University Hospital, S-17176 Stockholm (Sweden); Johansson, Jan [KI-Alzheimer' s Disease Research Center, NVS Department, Karolinska Institutet, S-141 86 Stockholm (Sweden); Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, S-751 23 Uppsala (Sweden); Joernvall, Hans, E-mail: Hans.Jornvall@ki.se [Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm (Sweden)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Insulin and C-peptide can interact under insulin fibril forming conditions. Black-Right-Pointing-Pointer C-peptide is incorporated into insulin aggregates and alters aggregation lag time. Black-Right-Pointing-Pointer C-peptide changes insulin fibril morphology and affects backbone accessibility. Black-Right-Pointing-Pointer C-peptide may be a regulator of fibril formation by {beta}-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic {beta}-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

  19. Probing the mechanism of insulin fibril formation with insulin mutants.

    Science.gov (United States)

    Nielsen, L; Frokjaer, S; Brange, J; Uversky, V N; Fink, A L

    2001-07-27

    The molecular basis of insulin fibril formation was investigated by studying the structural properties and kinetics of fibril formation of 20 different human insulin mutants at both low pH (conditions favoring monomer/dimer) and at pH 7.4 (conditions favoring tetramer/hexamer). Small-angle X-ray scattering showed insulin to be monomeric in 20% acetic acid, 0.1 M NaCl, pH 2. The secondary structure of the mutants was assessed using far-UV circular dichroism, and the tertiary structure was determined using near-UV circular dichroism, quenching of intrinsic fluorescence by acrylamide and interactions with the hydrophobic probe 1-anilino-8-naphthalene-sulfonic acid (ANS). The kinetics of fibril formation were monitored with the fluorescent dye, Thioflavin T. The results indicate that the monomer is the state from which fibrils arise, thus under some conditions dissociation of hexamers may be rate limiting or partially rate limiting. The insulin mutants were found to retain substantial nativelike secondary and tertiary structure under all conditions studied. The results suggest that fibril formation of the insulin mutants is controlled by specific molecular interactions that are sensitive to variations in the primary structure. The observed effects of several mutations on the rate of fibril formation are inconsistent with a previously suggested model for fibrillation [Brange, J., Whittingham, J., Edwards, D., Youshang, Z., Wollmer, A., Brandenburg, D., Dodson, G., and Finch, J. (1997) Curr. Sci. 72, 470-476]. Two surfaces on the insulin monomer are identified as potential interacting sites in insulin fibrils, one consisting of the residues B10, B16, and B17 and the other consisting of at least the residues A8 and B25. The marked increase in the lag time for fibril formation with mutations to more polar residues, as well as mutations to charged residues, demonstrates the importance of both hydrophobic and electrostatic interactions in the initial stages of fibrillation

  20. Normal and reversed supramolecular chirality of insulin fibrils probed by vibrational circular dichroism at the protofilament level of fibril structure.

    Science.gov (United States)

    Kurouski, Dmitry; Dukor, Rina K; Lu, Xuefang; Nafie, Laurence A; Lednev, Igor K

    2012-08-08

    Fibrils are β-sheet-rich aggregates that are generally composed of several protofibrils and may adopt variable morphologies, such as twisted ribbons or flat-like sheets. This polymorphism is observed for many different amyloid associated proteins and polypeptides. In a previous study we proposed the existence of another level of amyloid polymorphism, namely, that associated with fibril supramolecular chirality. Two chiral polymorphs of insulin, which can be controllably grown by means of small pH variations, exhibit opposite signs of vibrational circular dichroism (VCD) spectra. Herein, using atomic force microscopy (AFM) and scanning electron microscopy (SEM), we demonstrate that indeed VCD supramolecular chirality is correlated not only by the apparent fibril handedness but also by the sense of supramolecular chirality from a deeper level of chiral organization at the protofilament level of fibril structure. Our microscopic examination indicates that normal VCD fibrils have a left-handed twist, whereas reversed VCD fibrils are flat-like aggregates with no obvious helical twist as imaged by atomic force microscopy or scanning electron microscopy. A scheme is proposed consistent with observed data that features a dynamic equilibrium controlled by pH at the protofilament level between left- and right-twist fibril structures with distinctly different aggregation pathways for left- and right-twisted protofilaments. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Arbeit 4.0 in der Benutzungsabteilung einer großen Universitätsbibliothek

    Directory of Open Access Journals (Sweden)

    Silke Glitsch

    2016-06-01

    Full Text Available Die Digitalisierung der Arbeitswelt erreicht seit den 2010er-Jahren eine neue Dimension. Wie ihre Folgen die Arbeit der Benutzungsabteilung der Niedersächsischen Staats- und Universitätsbibliothek Göttingen prägen, erläutert der Bericht beispielhaft anhand der Einführung elektronischer Kassen an den Servicetheken und von Druck- und Kopierkonten für Privatnutzerinnen und -nutzer, der Einführung einer Dienstplansoftware, der Lernraumentwicklung der Bereichsbibliothek Medizin und der Entwicklung neuer Services für Promovierende. Since the 2010s, the digitisation of labour has been gaining a new dimension. This report describes how its consequences manifest themselves in the Readers’ Services Department at Göttingen State and University Library. The examples used for illustration are the introduction of electronic cash registers at the library’s service desks, of print and copy accounts for private users and of an employee scheduling software as well as the development of the Medical Library as a learning space and of new services for doctoral candidates.

  2. Organisation of municipal gas supply; Organisation einer kommunalen Gasversorgung. Theoretische und praktische Betrachtungen

    Energy Technology Data Exchange (ETDEWEB)

    Wolters, T.

    2000-07-01

    A safe supply of gas requires more than technically secure facilities and components. A structured and suitable organisation of the company's set-up and proceeding is necessary as well. In a diploma thesis, which was honored by the DVGW, theses aspects were treated as well in theory as well as in examples. Finally, a proposel for a gas supply company was developed which offered to translate into practice the results of the thesis. The thesis discusses issues of maintaining gas supply facilities and issues of the faultclearing service as well as aspects of the worker's protection laws. (orig.) [German] Eine sichere Gasversorgung verlangt mehr als technisch sichere Anlagen und Komponenten. Hierzu ist auch besonders eine planvolle und angemessene Aufbauorganisation und Ablauforganisation des Unternehmens notwendig. In einer vom DVGW ausgezeichneten Diplomarbeit wurden diese Aspekte theoretisch und an Beispielen erarbeitet, um letztlich einem Gasversorgungsunternehmen einen konkreten Vorschlag fuer die Umsetzung des Erarbeiteten zu unterbreiten. Fragen der Instandhaltung von Gasversorgungsanlagen und des Entstoerdienstes finden ebenso Beachtung wie die Umsetzung von Forderungen aus der Arbeitsschutzgesetzgebung. (orig.)

  3. Scenarios of a deregulated electricity industry. Analysis; Szenarien einer liberalisierten Stromversorgung. Analyse

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, G.

    2002-07-01

    Four scenarios have been established which represent the spectrum of probable developments in the Internal Market until 2010. The content-related postulations are described in two parts. In the first part, various fundamental settings are defined which apply to all four scenarios alike, whereas in the second part a set of influencing variables (descriptors) are defined which develop along dissimilar, distinctive lines and thus can be used for modelling within the four different scenarios. Applying a special scenario analysing method, the cross-impact method, those combinations of descriptors can be derived which lead to conclusive scenarios and consistent postulations. (orig./CB) [German] Es wurden vier Szenarien erarbeitet, die das Spektrum der wahrscheinlichen Entwicklungen im EU-Binnenmarkt bis zum Jahr 2010 repraesentieren. Die inhaltlichen Aussagen werden in zwei Teilen beschrieben. Der erste Teil beinhaltet eine Reihe von Rahmengroessen, die fuer alle vier Szenarien gleich sind. Der zweite Teil besteht aus einem Satz von Einflussgroessen (Deskriptoren) mit verschiedenen Auspraegungen, in denen sich die vier Szenarien unterscheiden. Mit Hilfe einer speziellen Szenariotechnik, der Cross-Impact-Methode, bestimmt man diejenigen Kombinationen der Deskriptorauspraegungen, die zu in sich schluessigen Szenarien ohne widerspruechliche Assagen fuehren. (orig./CB)

  4. Religion und Religionsunterricht in einer pluralen Gesellschaft. Empirische Perspektiven, entwickelt und kommentiert aus protestantischer Perspektive.

    Directory of Open Access Journals (Sweden)

    Hans-Günter Heimbrock

    2014-07-01

    Full Text Available ENGLISH: Sociology of religion assumes that the gap between personal believing and people`s belonging to religious groups in contemporary European societies is still growing. At the same time theologians often summon the idea of an overall decline of personal truth convictions anyhow. The article evaluates the empirical data from selected German schools looking for teacher`s personal adoption of religious orientation in subject-related ways. It evaluates the interplay between personal position-taking of teachers, their classroom practice and its constitutive factors (pupils, contexts of school and schooling etc.. DEUTSCH: Wie gehen Religionslehrkräfte an öffentlichen Schulen unter Bedingungen gesellschaftlicher Pluralisierung mit der eigenen religiösen Position um? Passt die Bezugnahme auf die eigene Glaubensüberzeugung noch in die Gegenwart? Der Beitrag skizziert Problemhorizonte dieser Frage, umreißt zentrale religionspädagogische Herausforderungen und entwickelt Antworten auf der Basis einer regionalen empirischen Untersuchung. Daraus ergibt sich eine neue Perspektive für den Konfessionsbezug des Religionsunterrichts.

  5. Design of a propeller turbine with a variable revolution number; Entwicklung einer Propellerturbine mit variabler Drehzahl

    Energy Technology Data Exchange (ETDEWEB)

    Fella, G.; Wierer, C. [Fella GmbH Maschinen- und Apparatebau, Amorbach (Germany); Goede, E.; Batrekhy, S.; Ruprecht, A. [Stuttgart Univ. (Germany). Inst. fuer Stroemungsmechanik und Hydraulische Stroemungsmaschinen

    1997-12-31

    The small hydroelectric power station of Rupboden in the Oberfranken district was reactivated after having been decommissioned for 30 years. This new low pressure plant consists of an open-flume turbine with an adjustable diffusor and a firm rotor disk (propeller) with a vertical rod. A large range of operation at a constant height of fall is ensured by a variable revolution number. The profiles of the adjustable diffusor and rotor disk and the design of the draft tube were optimized using numerical flow calculation. First operating experience is very positive. The turbine runs extremely smoothly over the entire range. (orig.) [Deutsch] Das Kleinwasserkraftwerk Rupboden in Oberfanken wurde nach 30 Jahren Stillstand reaktiviert. Die neue Niederdruckanlage besteht aus einer Schachtturbine mit verstellbarem Leitapparat, feststehendem Laufrad (Propeller) mit senkrechter Welle. Zum Erzielen eines grossen Betriebsbereiches bei gleichbleibender Fallhoehe wurde eine variable Drehzahl vorgesehen. Die Profilierung von Leitapparat und Laufrad sowie die Formgebung fuer das Saugrohr wurden mit numerischer Stroemungsberechnung optimiert. Erste Betriebserfahrungen sind sehr positiv. Die Turbine laeuft im gesamten Leistungsbereich ausserordentlich ruhig. (orig.)

  6. Medienbildung als konstruktive Aneignung von Medienensembles. Vorbemerkungen zu einer Theorie der Medienpädagogik

    Directory of Open Access Journals (Sweden)

    Tilman Bechthold-Hengelhaupt

    2016-12-01

    Full Text Available Die These dieses Aufsatzes lautet, dass im medienpädagogischen Handeln und Kommunizieren Erfahrungen mit dinglich gegebenen Medien verarbeitet und dass dadurch Medienensembles konstruiert werden, also praktisch verfügbare Konfigurationen von Geräten und Gegenständen, unter denen die beteiligten Akteure eine Auswahl treffen können. Der Begriff der Wahl lässt insbesondere einen Anschluss an die Idee einer demokratischen Medienbildung zu. Als erkenntnistheoretische Grundlage wird eine Orientierung an der sinnlichen Erfahrung vorgeschlagen, die gerade in Immanuel Kants "Kritik der reinen Vernunft" als Erkenntnisquelle begründet wird. Dass der Begriff der Medienensembles auch die historische Dimension aufschließen kann, wird am Beispiel des so genannten Neumagener Schulreliefs gezeigt, einem archäologischen Dokument aus der Zeit um 180 n.Chr. This essay proposes the thesis that media education should be understood as consisting in negotiations about experiences with media ensembles. In a constructivist approach, the acting with media ensembles is seen as a form of coming to terms with devices and other media objects that are accessible via sensory experience. In this context, a pivotal idea is that choices are made between different media that are at hand for educational purposes. This concept is further elaborated in the concepts of Immanuel Kant's theory of perception. As an example, an archaeological monument from ca. 180 AD ("Neumagener Schulrelief" is described and interpreted.

  7. Clinical characteristics, management, and control of permanent vs. nonpermanent atrial fibrillation: insights from the RealiseAF survey.

    LENUS (Irish Health Repository)

    Murin, Jan

    2014-01-01

    Atrial fibrillation can be categorized into nonpermanent and permanent atrial fibrillation. There is less information on permanent than on nonpermanent atrial fibrillation patients. This analysis aimed to describe the characteristics and current management, including the proportion of patients with successful atrial fibrillation control, of these atrial fibrillation subsets in a large, geographically diverse contemporary sample.

  8. Simple Model for Identifying Critical Regions in Atrial Fibrillation

    Science.gov (United States)

    Christensen, Kim; Manani, Kishan A.; Peters, Nicholas S.

    2015-01-01

    Atrial fibrillation (AF) is the most common abnormal heart rhythm and the single biggest cause of stroke. Ablation, destroying regions of the atria, is applied largely empirically and can be curative but with a disappointing clinical success rate. We design a simple model of activation wave front propagation on an anisotropic structure mimicking the branching network of heart muscle cells. This integration of phenomenological dynamics and pertinent structure shows how AF emerges spontaneously when the transverse cell-to-cell coupling decreases, as occurs with age, beyond a threshold value. We identify critical regions responsible for the initiation and maintenance of AF, the ablation of which terminates AF. The simplicity of the model allows us to calculate analytically the risk of arrhythmia and express the threshold value of transversal cell-to-cell coupling as a function of the model parameters. This threshold value decreases with increasing refractory period by reducing the number of critical regions which can initiate and sustain microreentrant circuits. These biologically testable predictions might inform ablation therapies and arrhythmic risk assessment.

  9. Attitudes Towards Catheter Ablation for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Vadmann, Henrik; Pedersen, Susanne S; Nielsen, Jens Cosedis

    2015-01-01

    BACKGROUND: Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians´ attitudes towards catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish...... cardiologists towards catheter ablation for AF, using a nationwide survey. METHODS AND RESULTS: We developed a purpose-designed questionnaire to evaluate attitudes towards catheter ablation for AF that was sent to all Danish cardiologists (n = 401; response n = 272 (67.8%)). There was no association between...... attitudes towards ablation and the experience or age of the cardiologist with respect to patients with recurrent AF episodes with a duration of 7 days and/or need for cardioversion. The majority (69%) expected a recurrence of AF after catheter ablation in more than 30% of the cases...

  10. Pathogenic Mechanisms of Atrial Fibrillation in Obesity

    Directory of Open Access Journals (Sweden)

    O. M. Drapkina

    2016-01-01

    Full Text Available Atrial fibrillation (AF is one of the most common arrhythmias. It reduces quality of life and its duration due to thromboembolic complications. Obesity contributes to the structural and electrical remodeling of atrial myocardium. This leads to occurrence of ectopic foci in the mouths of the pulmonary veins and the disruption of normal electrical conduction in the atria. Systemic inflammation, myocardial fibrosis, cardiomyocyte overload by Na+ and Ca2+ ions, accumulation in the cells of unoxidized metabolic products, imbalance of the autonomic regulation are considered as the main mechanisms of arrhythmogenic substrate formation. Hypertension, insulin resistance, and obstructive sleep apnea, associated with obesity, increase the risk of development and progression of the arrhythmia. Study of pathogenetic mechanisms of AF in obesity is necessary to develop new strategies for its prevention and the creation of more effective methods of treatment of these patients.

  11. Advances in Imaging for Atrial Fibrillation Ablation

    International Nuclear Information System (INIS)

    D'Silva, A.; Wright, M.; Wright, M.

    2011-01-01

    Over the last fifteen years, our understanding of the pathophysiology of atrial fibrillation (AF) has paved the way for ablation to be utilized as an effective treatment option. With the aim of gaining more detailed anatomical representation, advances have been made using various imaging modalities, both before and during the ablation procedure, in planning and execution. Options have flourished from procedural fluoroscopy, electro anatomic mapping systems, pre procedural computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and combinations of these technologies. Exciting work is underway in an effort to allow the electro physiologist to assess scar formation in real time. One advantage would be to lessen the learning curve for what are very complex procedures. The hope of these developments is to improve the likelihood of a successful ablation procedure and to allow more patients access to this treatment

  12. Alcohol and Atrial Fibrillation: A Sobering Review.

    Science.gov (United States)

    Voskoboinik, Aleksandr; Prabhu, Sandeep; Ling, Liang-Han; Kalman, Jonathan M; Kistler, Peter M

    2016-12-13

    Alcohol is popular in Western culture, supported by a perception that modest intake is cardioprotective. However, excessive drinking has detrimental implications for cardiovascular disease. Atrial fibrillation (AF) following an alcohol binge or the "holiday heart syndrome" is well characterized. However, more modest levels of alcohol intake on a regular basis may also increase the risk of AF. The pathophysiological mechanisms responsible for the relationship between alcohol and AF may include direct toxicity and alcohol's contribution to obesity, sleep-disordered breathing, and hypertension. We aim to provide a comprehensive review of the epidemiology and pathophysiology by which alcohol may be responsible for AF and determine whether alcohol abstinence is required for patients with AF. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. [Atrial fibrillation concomitant with valvular heart disease].

    Science.gov (United States)

    Ishii, Yosuke

    2013-01-01

    Patients with valvular heart disease frequently have atrial fibrillation(AF) due to elevated pressure and dilatation of the left and right atria and pulmonary veins. Guidelines for valvular heart disease and AF recommend that surgical treatment for the valvular heart disease should be performed concomitantly with AF surgery. The Full-Maze procedure has evolved into the gold standard of treatment for medically refractory AF. In addition to the pulmonary vein isolation, the right and left atrial incisions of the Full-Maze procedure are designed to block potential macroreentrant pathways. According to the mechanisms of AF with valvular heart disease, the Full-Maze procedure is more effective for the patients than the pulmonary vein isolation alone.

  14. Prognosis of ventricular fibrillation in hospital

    DEFF Research Database (Denmark)

    Jensen, G V; Torp-Pedersen, C; Køber, L

    1992-01-01

    In a retrospective study of 520 patients with in-hospital ventricular fibrillation 421 (81%) had acute myocardial infarction (MI), 66 (13%) had ischaemic heart disease (IHD) without MI, 33 (6%) had no signs of IHD. The in-hospital mortality of these three groups was 51%, 52%, and 27%, respectively...... (P = 0.01). Logistic regression analysis demonstrated that heart failure and cardiogenic shock were significant risk factors for in-hospital death among patients with IHD. Among discharged patients 1 and 5 years survival was 78% and 51% for patients with MI, 63% and 25% for patients with IHD, 67...... with known IHD suffering in-hospital VF without AMI have a very poor short- and long-term prognosis. These patients need extensive cardiac examination....

  15. Visualisation of collagen fibrils in joint cartilage using STIM

    International Nuclear Information System (INIS)

    Reinert, T.; Reibetanz, U.; Vogt, J.; Butz, T.; Werner, A.; Gruender, W.

    2001-01-01

    The scanning transmission ion microscopy (STIM) method was used to investigate the collagen network structure of the articular cartilage from a pig's knee in comparison with high resolution nuclear magnetic resonance imaging (microscopic NMR-tomography) and polarised light microscopy (PLM). Single collagen fibrils down to 200 nm in diameter were visualised. It was proved that the cartilage collagen network consists partly of zones of oriented fibrils as suggested by NMR measurements. Radially oriented fibrils were found in the zone near the calcified zone (hypertrophic zone) of both tibia and femur, and in the tibial radial zone. Tangentially oriented fibrils were found in the femoral and tibial superficial zone and in a second zone of the femoral cartilage. Polarisation light microscopy reveals broader zones of orientation than it was found with STIM

  16. Dabigatran use in Danish atrial fibrillation patients in 2011

    DEFF Research Database (Denmark)

    Sørensen, Rikke; Gislason, Gunnar; Torp-Pedersen, Christian Tobias

    2013-01-01

    Objective: Dabigatran was recently approved for anticoagulation in patients with atrial fibrillation (AF); data regarding real-world use, comparative effectiveness and safety are sparse. Design: Pharmacoepidemiological cohort study. Methods/settings: From nationwide registers, we identified...

  17. Analysis of XFEL serial diffraction data from individual crystalline fibrils

    Directory of Open Access Journals (Sweden)

    David H. Wojtas

    2017-11-01

    Full Text Available Serial diffraction data collected at the Linac Coherent Light Source from crystalline amyloid fibrils delivered in a liquid jet show that the fibrils are well oriented in the jet. At low fibril concentrations, diffraction patterns are recorded from single fibrils; these patterns are weak and contain only a few reflections. Methods are developed for determining the orientation of patterns in reciprocal space and merging them in three dimensions. This allows the individual structure amplitudes to be calculated, thus overcoming the limitations of orientation and cylindrical averaging in conventional fibre diffraction analysis. The advantages of this technique should allow structural studies of fibrous systems in biology that are inaccessible using existing techniques.

  18. Women Sex Importance in Stroke Patients with Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cemile Handan Mısırlı

    2014-08-01

    Full Text Available OBJECTIVE: It was shown the differences in age, risk factors and treatment between women and men in stroke patients with atrial fibrillation METHODS: The stroke patients with atrial fibrillation who were hospitalized in our department at the last 2 years were seperated into 2 groups of aged above 75 and below 75, investigated with CHADS2 and CHA2DS2VASc scores and looked at the sex differences of women and men. RESULTS: Stroke ratio according to sex was statistically meaningful especially in women above the age of 75. Risc factors also were founded in elderly women and CHA2DS2VASc scores were higher in women than men so more anticoagulan treatment were begun. No differences were shown between sexes at lone atrial fibrillation and no treatment were begun. CONCLUSION: Women with atrial fibrillation had more risk factors, higher stroke rate and higher anticoagulation treatment.

  19. Atrial fibrillation in the dog: a review of eight cases

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. E. [Vet. Hospital, 34 New Dover Rd, Canterbury, Kent (United Kingdom)

    1984-07-01

    Eight cases of canine atrial fibrillation encountered in small animal practice are reported. Details are included of age, sex and breed, history and clinical signs, thoracic radiography, electrocardiography, clinical pathology, treatment and survival periods.

  20. Atrial fibrillation in the dog: a review of eight cases

    International Nuclear Information System (INIS)

    Thomas, R.E.

    1984-01-01

    Eight cases of canine atrial fibrillation encountered in small animal practice are reported. Details are included of age, sex and breed, history and clinical signs, thoracic radiography, electrocardiography, clinical pathology, treatment and survival periods

  1. Inflammation in the genesis and perpetuation of atrial fibrillation

    DEFF Research Database (Denmark)

    Engelmann, Mads D M; Svendsen, Jesper Hastrup

    2005-01-01

    The prevalence and persistence of atrial fibrillation (AF) and the relative inefficacy of the currently available pharmacotherapy requires development of new treatment strategies. Recent findings have suggested a mechanistic link between inflammatory processes and the development of AF...

  2. How curcumin affords effective protection against amyloid fibrillation in insulin?

    DEFF Research Database (Denmark)

    Rabiee, Atefeh; Ebrahim Habibi, Azadeh; Ghasemi, Atiyeh Ghasemi

    2013-01-01

    Since the formation of amyloid structures from proteins was recognized in numerous diseases, many efforts have been devoted to the task of finding effective anti-amyloidogenic compounds. In a number of these investigations, the existence of “generic” compounds is implicitly acknowledged. Curcumin...... been shown effectively influenced by micro molar concentrations of curcumin. Under amyloidogenic conditions (pH 2.5 and 37°C), the compound was observed to inhibit fibril formation of insulin in a dose-dependent manner. Moreover, addition of curcumin to the protein incubated in such conditions...... at different time points resulted in reduced amounts of final fibrils. Disaggregation of pre-formed fibrils was also observed upon addition of curcumin, as well as reduction in final fibril amounts after seeding. Overall, this compound appears to be able to interact with native, intermediate and fibrillar...

  3. Ventricular fibrillation after accidental injection of bupivacaine into the pericardium

    NARCIS (Netherlands)

    Even, B. J.; de Jongh, R. F.; de Hert, S. G.

    1992-01-01

    A postoperative cardiac surgical patient developed ventricular fibrillation immediately after accidental pericardial injection of bupivacaine at room temperature. The possible causes, which include systemic toxicity, local vasoconstriction with myocardial ischaemia, local toxic effect of bupivacaine

  4. Long working hours as a risk factor for atrial fibrillation

    DEFF Research Database (Denmark)

    Kivimäki, Mika; Nyberg, Solja T.; Batty, G. David

    2017-01-01

    long hours (≤55 per week) and those working standard 35-40 h/week. Methods and results In this prospective multi-cohort study from the Individual-Participant-Data Meta-Analysis in Working Populations (IPD-Work) Consortium, the study population was 85 494 working men and women (mean age 43.4 years...... of atrial fibrillation (10-year cumulative incidence 12.4 per 1000). After adjustment for age, sex and socioeconomic status, individuals working long hours had a 1.4-fold increased risk of atrial fibrillation compared with those working standard hours (hazard ratio = 1.42, 95% CI= 1.13-1.80, P= 0......Aims Studies suggest that people who work long hours are at increased risk of stroke, but the association of long working hours with atrial fibrillation, the most common cardiac arrhythmia and a risk factor for stroke, is unknown. We examined the risk of atrial fibrillation in individuals working...

  5. Analysis of amyloid fibrils in the cheetah (Acinonyx jubatus).

    Science.gov (United States)

    Bergström, Joakim; Ueda, Mitsuharu; Une, Yumi; Sun, Xuguo; Misumi, Shogo; Shoji, Shozo; Ando, Yukio

    2006-06-01

    Recently, a high prevalence of amyloid A (AA) amyloidosis has been documented among captive cheetahs worldwide. Biochemical analysis of amyloid fibrils extracted from the liver of a Japanese captive cheetah unequivocally showed that protein AA was the main fibril constituent. Further characterization of the AA fibril components by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis revealed three main protein AA bands with approximate molecular weights of 8, 10 and 12 kDa. Mass spectrometry analysis of the 12-kDa component observed in SDS-PAGE and Western blotting confirmed the molecular weight of a 12,381-Da peak. Our finding of a 12-kDa protein AA component provides evidence that the cheetah SAA sequence is longer than the previously reported 90 amino acid residues (approximately 10 kDa), and hence SAA is part of the amyloid fibril.

  6. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in ...

  7. Insulin fibrillation: The influence and coordination of Zn2+

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Sønderby, Pernille; Bang, Maria Blanner

    2017-01-01

    fibrils has been debated for some years. We have therefore investigated the influence and binding geometry of zinc in fibrillated insulin using extended X-ray absorption fine-structure and X-ray absorption near-edge structure spectroscopy. The results were validated with fibre diffraction, Transmission...... Electron Microscopy and Thioflavin T fluorescence measurements. It is well-known that Zn2+ ions coordinate and stabilize the hexameric forms of insulin. However, this study is the first to show that zinc indeed binds to the insulin fibrils. Furthermore, zinc influences the kinetics and the morphology...... of the fibrils. It also shows that zinc coordinates to histidine residues in an environment, which is similar to the coordination seen in the insulin R6 hexamers, where three histidine residues and a chloride ion is coordinating the zinc....

  8. Ultrafast Hydrogen-Bonding Dynamics in Amyloid Fibrils.

    Science.gov (United States)

    Pazos, Ileana M; Ma, Jianqiang; Mukherjee, Debopreeti; Gai, Feng

    2018-06-08

    While there are many studies on the subject of hydrogen bonding dynamics in biological systems, few, if any, have investigated this fundamental process in amyloid fibrils. Herein, we seek to add insight into this topic by assessing the dynamics of a hydrogen bond buried in the dry interface of amyloid fibrils. To prepare a suitable model peptide system for this purpose, we introduce two mutations into the amyloid-forming Aβ(16-22) peptide. The first one is a lysine analog at position 19, which is used to help form structurally homogeneous fibrils, and the second one is an aspartic acid derivative (DM) at position 17, which is intended (1) to be used as a site-specific infrared probe and (2) to serve as a hydrogen-bond acceptor to lysine so that an inter-β-sheet hydrogen bond can be formed in the fibrils. Using both infrared spectroscopy and atomic force microscopy, we show that (1) this mutant peptide indeed forms well defined fibrils, (2) when bulk solvent is removed, there is no detectable water present in the fibrils, (3) infrared results obtained with the DM probe are consistent with a protofibril structure that is composed of two antiparallel β-sheets stacked in a parallel fashion, leading to formation of the expected hydrogen bond. Using two-dimensional infrared spectroscopy, we further show that the dynamics of this hydrogen bond occur on a timescale of ~2.3 ps, which is attributed to the rapid rotation of the -NH3+ group of lysine around its Cε-Nζ bond. Taken together, these results suggest that (1) DM is a useful infrared marker in facilitating structure determination of amyloid fibrils and (2) even in the tightly packed core of amyloid fibrils certain amino acid sidechains can undergo ultrafast motions, hence contributing to the thermodynamic stability of the system.

  9. Stroke and bleeding in atrial fibrillation with chronic kidney disease

    DEFF Research Database (Denmark)

    Olesen, Jonas Bjerring; Lip, Gregory Y.H.; Kamper, Anne-Lise

    2012-01-01

    Both atrial fibrillation and chronic kidney disease increase the risk of stroke and systemic thromboembolism. However, these risks, and the effects of antithrombotic treatment, have not been thoroughly investigated in patients with both conditions.......Both atrial fibrillation and chronic kidney disease increase the risk of stroke and systemic thromboembolism. However, these risks, and the effects of antithrombotic treatment, have not been thoroughly investigated in patients with both conditions....

  10. Nanomechanical mapping of hydrated rat tail tendon collagen I fibrils.

    Science.gov (United States)

    Baldwin, Samuel J; Quigley, Andrew S; Clegg, Charlotte; Kreplak, Laurent

    2014-10-21

    Collagen fibrils play an important role in the human body, providing tensile strength to connective tissues. These fibrils are characterized by a banding pattern with a D-period of 67 nm. The proposed origin of the D-period is the internal staggering of tropocollagen molecules within the fibril, leading to gap and overlap regions and a corresponding periodic density fluctuation. Using an atomic force microscope high-resolution modulus maps of collagen fibril segments, up to 80 μm in length, were acquired at indentation speeds around 10(5) nm/s. The maps revealed a periodic modulation corresponding to the D-period as well as previously undocumented micrometer scale fluctuations. Further analysis revealed a 4/5, gap/overlap, ratio in the measured modulus providing further support for the quarter-staggered model of collagen fibril axial structure. The modulus values obtained at indentation speeds around 10(5) nm/s are significantly larger than those previously reported. Probing the effect of indentation speed over four decades reveals two distinct logarithmic regimes of the measured modulus and point to the existence of a characteristic molecular relaxation time around 0.1 ms. Furthermore, collagen fibrils exposed to temperatures between 50 and 62°C and cooled back to room temperature show a sharp decrease in modulus and a sharp increase in fibril diameter. This is also associated with a disappearance of the D-period and the appearance of twisted subfibrils with a pitch in the micrometer range. Based on all these data and a similar behavior observed for cross-linked polymer networks below the glass transition temperature, we propose that collagen I fibrils may be in a glassy state while hydrated.

  11. Fibrillization kinetics of insulin solution in an interfacial shearing flow

    Science.gov (United States)

    Balaraj, Vignesh; McBride, Samantha; Hirsa, Amir; Lopez, Juan

    2015-11-01

    Although the association of fibril plaques with neurodegenerative diseases like Alzheimer's and Parkinson's is well established, in-depth understanding of the roles played by various physical factors in seeding and growth of fibrils is far from well known. Of the numerous factors affecting this complex phenomenon, the effect of fluid flow and shear at interfaces is paramount as it is ubiquitous and the most varying factor in vivo. Many amyloidogenic proteins have been found to denature upon contact at hydrophobic interfaces due to the self-assembling nature of protein in its monomeric state. Here, fibrillization kinetics of insulin solution is studied in an interfacial shearing flow. The transient surface rheological response of the insulin solution to the flow and its effect on the bulk fibrillization process has been quantified. Minute differences in hydrophobic characteristics between two variants of insulin- Human recombinant and Bovine insulin are found to result in very different responses. Results presented will be in the form of fibrillization assays, images of fibril plaques formed, and changes in surface rheological properties of the insulin solution. The interfacial velocity field, measured from images (via Brewster Angle Microscopy), is compared with computations. Supported by NNX13AQ22G, National Aeronautics and Space Administration.

  12. Viologen-Phosphorus Dendrimers Inhibit α-Synuclein Fibrillation.

    Science.gov (United States)

    Milowska, Katarzyna; Grochowina, Justyna; Katir, Nadia; El Kadib, Abdelkrim; Majoral, Jean-Pierre; Bryszewska, Maria; Gabryelak, Teresa

    2013-03-04

    Inhibition of α-synuclein (ASN) fibril formation is a potential therapeutic strategy in Parkinson's disease and other synucleinopathies. The aim of this study was to examine the role of viologen-phosphorus dendrimers in the α-synuclein fibrillation process and to assess the structural changes in α-synuclein under the influence of dendrimers. ASN interactions with phosphonate and pegylated surface-reactive viologen-phosphorus dendrimers were examined by measuring the zeta potential, which allowed determining the number of dendrimer molecules that bind to the ASN molecule. The fibrillation kinetics and the structural changes were examined using ThT fluorescence and CD spectroscopy. Depending on the concentration of the used dendrimer and the nature of the reactive groups located on the surface, ASN fibrillation kinetics can be significantly reduced, and even, in the specific case of phosphonate dendrimers, the fibrillation can be totally inhibited at low concentrations. The presented results indicate that viologen-phosphorus dendrimers are able to inhibit ASN fibril formation and may be used as fibrillar regulating agents in neurodegenerative disorders.

  13. Stabilization and anomalous hydration of collagen fibril under heating.

    Directory of Open Access Journals (Sweden)

    Sasun G Gevorkian

    Full Text Available BACKGROUND: Type I collagen is the most common protein among higher vertebrates. It forms the basis of fibrous connective tissues (tendon, chord, skin, bones and ensures mechanical stability and strength of these tissues. It is known, however, that separate triple-helical collagen macromolecules are unstable at physiological temperatures. We want to understand the mechanism of collagen stability at the intermolecular level. To this end, we study the collagen fibril, an intermediate level in the collagen hierarchy between triple-helical macromolecule and tendon. METHODOLOGY/PRINCIPAL FINDING: When heating a native fibril sample, its Young's modulus decreases in temperature range 20-58°C due to partial denaturation of triple-helices, but it is approximately constant at 58-75°C, because of stabilization by inter-molecular interactions. The stabilization temperature range 58-75°C has two further important features: here the fibril absorbs water under heating and the internal friction displays a peak. We relate these experimental findings to restructuring of collagen triple-helices in fibril. A theoretical description of the experimental results is provided via a generalization of the standard Zimm-Bragg model for the helix-coil transition. It takes into account intermolecular interactions of collagen triple-helices in fibril and describes water adsorption via the Langmuir mechanism. CONCLUSION/SIGNIFICANCE: We uncovered an inter-molecular mechanism that stabilizes the fibril made of unstable collagen macromolecules. This mechanism can be relevant for explaining stability of collagen.

  14. Sich selbst und den anderen aus einer asymmetrischen Position verstehen – Die Kunst der Unterscheidung

    Directory of Open Access Journals (Sweden)

    Marek Čikel

    2016-12-01

    Full Text Available Sich selbst und den Anderen zu kennen setzt immer eine asymmetrische Position voraus. Die Person ist darauf gestellt, diese Leistung aus einer Position durchzuführen, die keine klare Orientierung ermöglicht und unsere derzeitigen Dispositionen beträchtlich übersteigt. Dem Menschen wird schließlich immer so viel gezeigt, damit er weiß und sieht, aber nicht so klar, damit er auch versteht. Die Art und Weise, in welcher eine Person mit sich selbst, mit dem Zorn, der Frustration, den Leidenschaften, der Sprache umgeht, vermittelt Informationen über individuelle Regungen der Seele, über Bewältigungsmechanismen. Man kann sie für eine gewisse Hilfestellung der Sprache selbst halten. Aber das Verständnis dieser Hilfestellung und des Ratschlags nur im Verhältnis zu sich selbst wäre zu eng. Wir wollen oder bekommen oft Ratschläge, die andere betreffen, aber wir müssen sie „aus sich selbst“ lösen. Und gerade aus sich selbst sollen wir fragen und sprechen. Im Augenblick, wenn diese Tiefe des Sprechens und Hörens erreicht wird, eröffnet sich die Möglichkeit, mit sich selbst und mit dem Anderen zu sein. Es ist jedoch zugleich ein Augenblick des Kampfes, der sich am Hintergrund des Gehörten konstituiert, das am Anfang oft als etwas Unverständliches erscheint oder das durch Vorstellungen und Schmerzen gestört wird. Die Antwort auf diesen Kampf ist die Kunst der Unterscheidung.

  15. Testing and modification of a simple flow turbine; Messtechnische Untersuchung und Modifikation einer einfachen Durchstroemturbine

    Energy Technology Data Exchange (ETDEWEB)

    Gentner, C. [Stuttgart Univ. (Germany). Inst. fuer Stroemungsmechanik und Hydraulische Stroemungsmaschinen; Fischer, G. [SKAT, St. Gallen (Switzerland)

    1997-12-31

    A study conducted at the IHS had the aim to obtain basic information on whether it is possible to build flow turbines following the free jet principle that are on a par with, or superior to, the conventional design, especially in terms of performance and the efficiency curve. Several inflow contours with a ventilated free jet and a conventional flow turbine were studied. The direct comparison of these variants revealed a slightly enhanced peak load efficiency and a very distinct superiority of the free jet contour during partial load. But the efficiency of all variants failed to attain the values claimed by commercial manufacturers. As compared to the initial contour, peak load efficiency was enhanced by 5 per cent. During partial load, the variants studied showed a distinct superiority of the free jet concept over the contour of conventional flow turbines. (orig.) [Deutsch] Am IHS wurde eine Untersuchung mit dem Ziel durchgefuehrt, grundlegende Aussagen zu gewinnen, ob Durchstroemturbinen mit dem Freistrahlprinzip gebaut werden koennen, die dem konventionellen Design, vor allem in bezug auf Leistungsausbeute und Wirkungsgradverlauf, gleichwertig oder ueberlegen sind. Es wurden mehrere Anstroemkonturen mit belueftetem Freistrahl und einer konventionellen Durchstroemturbine untersucht. Der direkte Vergleich der am Institut untersuchten Varianten ergab bei etwas hoeherem Spitzenwirkungsgrad sehr deutliche Vorteile der Freistrahlkontur im Teillastbereich. Das Wirkungsgradniveau aller Varianten lag jedoch unter den Werten, die von kommerziellen Herstellern veroeffentlicht werden. Gegenueber der Ausgangskontur wurde im Spitzenwirkungsgrad eine Verbesserung von 5% erreicht. Im Teillastbereich ergibt sich fuer die hier untersuchten Varianten eine deutliche Ueberlegenheit der Freistrahlkonzeption ueber die Kontur konventioneller Durchstroemturbinen. (orig.)

  16. The architecture of amyloid-like peptide fibrils revealed by X-ray scattering, diffraction and electron microscopy

    DEFF Research Database (Denmark)

    Langkilde, Annette Eva; Morris, Kyle L; Serpell, Louise C

    2015-01-01

    Structural analysis of protein fibrillation is inherently challenging. Given the crucial role of fibrils in amyloid diseases, method advancement is urgently needed. A hybrid modelling approach is presented enabling detailed analysis of a highly ordered and hierarchically organized fibril of the G......Structural analysis of protein fibrillation is inherently challenging. Given the crucial role of fibrils in amyloid diseases, method advancement is urgently needed. A hybrid modelling approach is presented enabling detailed analysis of a highly ordered and hierarchically organized fibril...

  17. Diagnose und Therapie einer Depression im höheren Lebensalter – Einflüsse von Patienten- und Arztmerkmalen

    Science.gov (United States)

    von dem Knesebeck, Olaf; Bönte, Markus; Siegrist, Johannes; Marceau, Lisa; Link, Carol; McKinlay, John

    2013-01-01

    Zusammenfassung Studienergebnissee aus dem englischsprachigen Raum zeigen, dass diagnostische und therapeutische Entscheidungen von Hausärzten bei der Versorgung von depressiven Patienten systematischen Einflüssen unterliegen, und dass sowohl Merkmale des Arztes als auch des Patienten unabhängig vom Krankheitsbild Einfluss auf diese Entscheidungen haben. In der vorliegenden Arbeit werden Ergebnisse einer deutschen Studie präsentiert, in der die Einflüsse von Patienten- und Arztmerkmalen auf diagnostische und therapeutische ärztliche Entscheidungen bei einer Depression untersucht wurden. Unter Anwendung eines faktoriellen Experimentaldesigns spielten professionelle Schauspieler in Videofilmen die Rolle von Patienten, die Symptome für eine depressive Erkrankung äußern. In den Videofilmen, die alle auf einem identischen Skript basieren, wurden systematisch die Patientenmerkmale Alter (55 vs. 75 Jahre), Geschlecht und sozialer Status (Hausmeister vs. Lehrer) variiert. Die randomisierte Ärztestichprobe wurde nach dem Arztgeschlecht und professioneller Erfahrung ( 15 Jahre) geschichtet. Der Videofilm wurde insgesamt 128 niedergelassenen Ärzten für Allgemeinmedizin und hausärztlich tätigen Internisten in ihrer Praxis vorgespielt. Danach wurden die Ärzte zu unterschiedlichen Aspekten von Diagnose und Therapie befragt. Es wurde erhoben, ob der Arzt dem Patienten über das gezeigte Gespräch hinausgehende Fragen stellen würde, welche Diagnosen er für wahrscheinlich hält, wie sicher er sich mit seiner Diagnose ist, welche diagnostischen Tests er anordnen würde, ob er den Patienten überweisen würde oder ob er Medikamente verordnen oder ihm Empfehlungen zur Änderung seines Lebensstils geben würde. Die Ergebnisse weisen darauf hin, dass sowohl die Diagnose als auch die Therapie einer Depression durch niedergelassene Hausärzte in Deutschland nur geringfügig durch die untersuchten Merkmale der Patienten und der behandelnden Ärzte beeinflusst wird. PMID

  18. Practical implementation of a quality management system in a radiological department; Praktische Umsetzung von Qualitaetsmanagement in einer radiologischen Abteilung

    Energy Technology Data Exchange (ETDEWEB)

    Huber, S.; Zech, C.J. [Klinikum der Ludwig-Maximilians-Universitaet, Campus Innenstadt, Institut fuer Klinische Radiologie, Muenchen (Germany)

    2011-10-15

    This article describes the architecture of a project aiming to implement a DIN EN ISO 9001 quality management system in a radiological department. It is intended to be a practical guide to demonstrate each step of the project leading to certification of the system. In a planning phase resources for the implementation of the project have to be identified and a quality management (QM) group as core team has to be formed. In the first project phase all available documents have to be checked and compiled in the QM manual. Moreover all relevant processes of the department have to be described in so-called process descriptions. In a second step responsibilities for the project are identified. Customer and employee surveys have to be carried out and a nonconformity management system has to be implemented. In this phase internal audits are also needed to check the new QM system, which is finally tested in the external certification audit with reference to its conformity with the standards. (orig.) [German] Dieser Beitrag beschreibt die Grundarchitektur einer Projektplanung fuer die Etablierung eines Qualitaetsmanagement(QM)-Systems mit Zertifizierung nach DIN EN ISO 9001 fuer eine radiologische Abteilung basierend auf eigenen Erfahrungen und der einschlaegigen Praxis. Er soll ein praktischer Leitfaden fuer die einzelnen Arbeitsschritte waehrend eines solchen Zertifizierungsprojekts sein. In einer Planungsphase muessen die erforderlichen Ressourcen fuer ein Zertifizierungsprojekt erfasst und eine QM-Gruppe als Kernteam gebildet werden. In der ersten Projektphase werden die Dokumente und Vorlagen der Abteilung gesichtet und in einem Handbuch gelenkt. Zudem muessen fuer alle wesentlichen Prozesse Beschreibungen erstellt werden. In einer zweiten Projektphase werden weitere Verantwortlichkeiten im Rahmen eines Beauftragtenwesens festgelegt, Befragungen relevanter ''Kunden'' (Patienten, Zuweiser) und Mitarbeiter durchgefuehrt und ein Fehler- und

  19. Erictho und die Figuren der Entzweiung – Vorüberlegungen zu einer Poetik der Emergenz in Lucans Bellum civile

    Directory of Open Access Journals (Sweden)

    Alexander Arweiler

    2010-10-01

    Full Text Available Im Ausgang von der Möglichkeit, mit dem Wort figura Gestalten der Handlungsebene, dynamisch gefaßte Gedanken- / Wortgebilde und Erscheinungsweisen von Phänomenen geistiger und materieller Natur zu bezeichnen, läßt sich das Bellum civile als Werk beschreiben, an dessen Grund die Figur der Entzweiung steht, die durch eine Poetik der Emergenz in den Stoff entfaltet wird. Die vorgeschlagene Lektüre des Bellum civile wendet sich damit gegen das verbreitete Verständnis des Textes als eines (politischen, moralischen Kommentars zum Bürgerkrieg und kehrt die Hierarchie um: Der (sekundäre Bürgerkriegsstoff soll die zugrunde liegende Figur der Entzweiung explizieren, wird von dieser aber nicht gedeutet, sondern benutzt. Emergenz tritt als poetische Verhältnisbestimmung an die Stelle chronologischer und kausaler Erklärungsmodelle und behauptet eine bleibende Verbindung von Untergrund und hervortretendem Relief (Ereignis, Wesen, Gestalt. Dementsprechend lassen sich die Gestalten der Handlungsebene (figurae als Ekstasen des Textes fassen, die in einer Verdichtung des Textes aus dessen Oberfläche hervortreten, zugleich gemeinsam mit anderen Textelementen Erscheinungsweisen (figurae der abstrakten Figur der Entzweiung sind. Im sechsten Buch des Bellum civile wird die Ekstase insbesondere im Hervorgehen der Erictho aus der Konstruktion eines raum-zeitlich unmöglichen Thessalien kompositionell konkretisiert und imitationstechnischumgesetzt: Die ovidisch geprägte Begegnungsszenezwischen Sextus Pompeius und der textuell übercodierten Erictho bereitet den Boden für die Auffassung der Hexesowohl als einer Fortschreibung der nach Ovid vergehenden Sibylle als auch als figura (Gestalt und Erscheinungsweise Roms, das sich in einer Trennung von sich selbst gegenübertritt und im (poetischen Kannibalismus die Entzweiung zumVollzug bringt.

  20. Recurrence of pulmonary vein conduction and atrial fibrillation after pulmonary vein isolation for atrial fibrillation

    DEFF Research Database (Denmark)

    Nilsson, Brian; Chen, Xu; Pehrson, Steen

    2006-01-01

    BACKGROUND: Both segmental ostial and circumferential extraostial pulmonary vein (PV) isolation have been proven effective in the treatment of atrial fibrillation (AF). However, the recurrence of AF and PV conduction after the 2 ablation strategies has never been compared in a randomized study...... isolation. Extraostial PV isolation was performed by encircling the paired left and right PVs, respectively, guided by an electroanatomic mapping system. RESULTS: A total of 84% of the patients had recurrent AF after the first PV isolation procedure, showing 72% with AF and 12% with organized left atrial...

  1. Neue Elektrolyte zur Steigerung der Energiedichte einer nicht-wässrigen Vanadium-Acetylacetonat-Redox-Flow-Batterie

    OpenAIRE

    Herr, Tatjana

    2015-01-01

    Die Redox-Flow-Batterie ist eine vielversprechende Speicherungsmöglichkeit für stationäre Anwendungen. Bei dieser Batterie wird die Energie in einem flüssigen Elektrolyt gespeichert, wobei die Energiedichte von der Konzentration und dem Potentialfenster der gelösten redoxaktiven Substanz abhängt. Zur Steigerung der Energiedichte einer nicht-wässrigen Vanadium-Acetylacetonat-Redox-Flow-Batterie wurden organische Lösungsmittel, welche ein Potentialfenster bis zu 5 V aufweisen, und Lösungsmittel...

  2. Scintigraphic diagnosis of silent aspiration following double-sided lung transplantation; Szintigraphischer Nachweis einer stillen Aspiration nach beidseitiger Lungentransplantation

    Energy Technology Data Exchange (ETDEWEB)

    Toenshoff, G. [Kiel Univ. (Germany). Klinik fuer Nuklearmedizin; Stock, U. [Kiel Univ. (Germany). Klinik fuer Herz- und Gefaesschirurgie; Bohuslavizki, K.H. [Kiel Univ. (Germany). Klinik fuer Nuklearmedizin; Brenner, W. [Kiel Univ. (Germany). Klinik fuer Nuklearmedizin; Costard-Jaeckle, A. [Kiel Univ. (Germany). Klinik fuer Herz- und Gefaesschirurgie; Cremer, J. [Kiel Univ. (Germany). Klinik fuer Herz- und Gefaesschirurgie; Clausen, M. [Kiel Univ. (Germany). Klinik fuer Nuklearmedizin

    1996-08-01

    We present a case of a 25 year old patient who underwent double-sided lung transplantation and suffered from recurrent pneumonia. Silent aspiration was suspected clinically. Aspiration was proved by scintigraphy enabling to discriminate between direct oro-pulmonal aspiration and aspiration after gastro-esophageal reflux. (orig.) [Deutsch] Vorgestellt wird der Fall einer 25jaehrigen Patientin nach beidseitiger Lungentransplantation und rezidivierenden Pneumonien. Klinisch bestand der Verdacht auf eine stille Aspiration. Szintigraphisch gelang sowohl der Aspirationsnachweis als auch eine Differenzierung hinsichtlich der Genese: Direkte oro-pulmonale Aspiration versus Aspiration nach gastrooesophagealem Reflux. (orig.)

  3. The inhalation toxicology of p-aramid fibrils.

    Science.gov (United States)

    Donaldson, Ken

    2009-01-01

    The pandemic of lung disease caused by asbestos has cast suspicion on any industrial fibrous material that can become airborne in respirable form in workplaces, such that the respirable fibres might be inhaled. Fibre toxicology arose as a sub-specialty of particle toxicology to address the specialised nature of fibre effects and has evolved substantially in the last 25 years. It has yielded valuable information on the dosimetry, structure-activity relationships, and mechanism involved in toxicological effects of a range of fibrous materials, including asbestos, other naturally occurring fibrous materials, and synthetic vitreous fibres. A robust structure/activity paradigm has emerged from this research that highlights fibre length, thinness, and biopersistence as major factors in determining the pathogenicity of a fibre. p-Aramid is a manufactured fibre composed of synthetic polyamide (poly paraphenylene terephthalamide) manufactured on a commercial scale since 1970 by polymerisation and spinning steps. It is used as an advanced composite and in fabrics, body armour, friction materials, etc. Respirable fibrils of p-aramid can be released from the fibres during working and can become airborne. A considerable body of research has been carried out into the hazard posed by inhaled p-aramid fibrils, and this review considers this body of literature and summarises the state-of-the-science in the toxicology of p-aramid fibrils in the light of the existing overarching fibre toxicology paradigm. The peer-reviewed studies demonstrate that p-aramid fibrils can be long and thin but that the fibrils are not biopersistent. Residence in the milieu of the lungs leads to fibre shortening, allowing efficient and complete phagocytosis and effective clearance. Subsequently the p-aramid hazard is low, and this is confirmed in animal studies. The mechanism of shortening of p-aramid fibrils is not well-understood, but may involve the action of macrophages on the fibrils following

  4. Wool fibril sponges with perspective biomedical applications

    International Nuclear Information System (INIS)

    Patrucco, A.; Cristofaro, F.; Simionati, M.; Zoccola, M.; Bruni, G.; Fassina, L.; Visai, L.; Magenes, G.

    2016-01-01

    Sheep's wool was used as a natural source to prepare keratin microfibril sponges for scaffolding, by disruption of the histological structure of the fibres through mild alkali treatment, followed by ultrasonication, casting and salt-leaching. The wool sponges showed highly interconnected porosity (93%) and contain intrinsic sites of cellular recognition that mimic the extracellular matrix (ECM). They displayed good thermal and water stability due to the conversion of disulphide cystine bonds into shorter monosulphide lanthionine intermolecular bonds, but significantly swelled in water, because of the high hydrophilicity and porosity, with a volume increasing up to 38%. Nevertheless, sponges were stable in water without structural changes, with a neutral pH in aqueous media, and showed excellent resilience to repeated compression stresses. According to in vitro biocompatibility assays, wool fibril sponges showed a good cell adhesion and proliferation as proved by MTT, FDA assays and SEM observations. The unique structure of the cortical cell network made by wool keratin proteins with controlled-size macro-porosity suitable for cell guesting, and nutrient feeding, provides an excellent scaffold for future tissue engineering applications. - Highlights: • Scaffolds were prepared from wool exploiting the fibres' histology structure. • The scaffold showed high interconnected micro- and macro-porosity. • The microscopic structure is very similar to the extracellular bone matrix. • Scaffolds reversibly swell in water with high resilience to repeated compression. • Composites were cytocompatible and supported the growth of SAOS-2 cell line.

  5. Red Wine, Resveratrol and Atrial Fibrillation

    Science.gov (United States)

    Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF. PMID:29084143

  6. Red Wine, Resveratrol and Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Laura Siga Stephan

    2017-10-01

    Full Text Available Atrial fibrillation (AF is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  7. Red Wine, Resveratrol and Atrial Fibrillation.

    Science.gov (United States)

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-10-30

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  8. Imaging in percutaneous ablation for atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Maksimovic, Ruzica [Erasmus Medical Center, Department of Radiology, GD Rotterdam (Netherlands); Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia); Dill, Thorsten [Kerckhoff-Heart Center, Department of Cardiology, Bad Nauheim (Germany); Ristic, Arsen D.; Seferovic, Petar M. [Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia)

    2006-11-15

    Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients. (orig.)

  9. Atrial fibrillation: effects beyond the atrium?

    Science.gov (United States)

    Wijesurendra, Rohan S; Casadei, Barbara

    2015-03-01

    Atrial fibrillation (AF) is the most common sustained clinical arrhythmia and is associated with significant morbidity, mostly secondary to heart failure and stroke, and an estimated two-fold increase in premature death. Efforts to increase our understanding of AF and its complications have focused on unravelling the mechanisms of electrical and structural remodelling of the atrial myocardium. Yet, it is increasingly recognized that AF is more than an atrial disease, being associated with systemic inflammation, endothelial dysfunction, and adverse effects on the structure and function of the left ventricular myocardium that may be prognostically important. Here, we review the molecular and in vivo evidence that underpins current knowledge regarding the effects of human or experimental AF on the ventricular myocardium. Potential mechanisms are explored including diffuse ventricular fibrosis, focal myocardial scarring, and impaired myocardial perfusion and perfusion reserve. The complex relationship between AF, systemic inflammation, as well as endothelial/microvascular dysfunction and the effects of AF on ventricular calcium handling and oxidative stress are also addressed. Finally, consideration is given to the clinical implications of these observations and concepts, with particular reference to rate vs. rhythm control. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

  10. Imaging in percutaneous ablation for atrial fibrillation

    International Nuclear Information System (INIS)

    Maksimovic, Ruzica; Dill, Thorsten; Ristic, Arsen D.; Seferovic, Petar M.

    2006-01-01

    Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients. (orig.)

  11. Wool fibril sponges with perspective biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Patrucco, A., E-mail: a.patrucco@bi.ismac.cnr.it [CNR-ISMAC, Italian National Research Council, Institute for Macromolecular Studies, Corso G. Pella 16, 13900, Biella (Italy); Cristofaro, F., E-mail: francesco.cristofaro01@universitadipavia.it [Department of Molecular Medicine, INSTM UdR of Pavia, University of Pavia, Viale Taramelli 3/B, 27100, Pavia (Italy); Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Simionati, M., E-mail: m.simionati@bi.ismac.cnr.it [CNR-ISMAC, Italian National Research Council, Institute for Macromolecular Studies, Corso G. Pella 16, 13900, Biella (Italy); Zoccola, M., E-mail: m.zoccola@bi.ismac.cnr.it [CNR-ISMAC, Italian National Research Council, Institute for Macromolecular Studies, Corso G. Pella 16, 13900, Biella (Italy); Bruni, G., E-mail: giovanna.bruni@unipv.it [Department of Chemistry, — Physical-Chemistry Section, University of Pavia, Viale Taramelli 16, 27100, Pavia (Italy); Fassina, L., E-mail: lorenzo.fassina@unipv.it [Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Visai, L., E-mail: livia.visai@unipv.it [Department of Molecular Medicine, INSTM UdR of Pavia, University of Pavia, Viale Taramelli 3/B, 27100, Pavia (Italy); Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Department of Occupational Medicine, Toxicology and Environmental Risks, S. Maugeri Foundation, IRCCS, Via S. Boezio, 28, 27100, Pavia (Italy); Magenes, G., E-mail: giovanni.magenes@unipv.it [Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); and others

    2016-04-01

    Sheep's wool was used as a natural source to prepare keratin microfibril sponges for scaffolding, by disruption of the histological structure of the fibres through mild alkali treatment, followed by ultrasonication, casting and salt-leaching. The wool sponges showed highly interconnected porosity (93%) and contain intrinsic sites of cellular recognition that mimic the extracellular matrix (ECM). They displayed good thermal and water stability due to the conversion of disulphide cystine bonds into shorter monosulphide lanthionine intermolecular bonds, but significantly swelled in water, because of the high hydrophilicity and porosity, with a volume increasing up to 38%. Nevertheless, sponges were stable in water without structural changes, with a neutral pH in aqueous media, and showed excellent resilience to repeated compression stresses. According to in vitro biocompatibility assays, wool fibril sponges showed a good cell adhesion and proliferation as proved by MTT, FDA assays and SEM observations. The unique structure of the cortical cell network made by wool keratin proteins with controlled-size macro-porosity suitable for cell guesting, and nutrient feeding, provides an excellent scaffold for future tissue engineering applications. - Highlights: • Scaffolds were prepared from wool exploiting the fibres' histology structure. • The scaffold showed high interconnected micro- and macro-porosity. • The microscopic structure is very similar to the extracellular bone matrix. • Scaffolds reversibly swell in water with high resilience to repeated compression. • Composites were cytocompatible and supported the growth of SAOS-2 cell line.

  12. Ventricular fibrillation time constant for swine

    International Nuclear Information System (INIS)

    Wu, Jiun-Yan; Sun, Hongyu; Nimunkar, Amit J; Webster, John G; O'Rourke, Ann; Huebner, Shane; Will, James A

    2008-01-01

    The strength–duration curve for cardiac excitation can be modeled by a parallel resistor–capacitor circuit that has a time constant. Experiments on six pigs were performed by delivering current from the X26 Taser dart at a distance from the heart to cause ventricular fibrillation (VF). The X26 Taser is an electromuscular incapacitation device (EMD), which generates about 50 kV and delivers a pulse train of about 15–19 pulses s −1 with a pulse duration of about 150 µs and peak current about 2 A. Similarly a continuous 60 Hz alternating current of the amplitude required to cause VF was delivered from the same distance. The average current and duration of the current pulse were estimated in both sets of experiments. The strength–duration equation was solved to yield an average time constant of 2.87 ms ± 1.90 (SD). Results obtained may help in the development of safety standards for future electromuscular incapacitation devices (EMDs) without requiring additional animal tests

  13. The mechanisms of atrial fibrillation in hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Bielecka-Dabrowa Agata

    2009-04-01

    Full Text Available Abstract Atrial fibrillation (AF is a complex condition with several possible contributing factors. The rapid and irregular heartbeat produced by AF increases the risk of blood clot formation inside the heart. These clots may eventually become dislodged, causing embolism, stroke and other disorders. AF occurs in up to 15% of patients with hyperthyroidism compared to 4% of people in the general population and is more common in men and in patients with triiodothyronine (T3 toxicosis. The incidence of AF increases with advancing age. Also, subclinical hyperthyroidism is a risk factor associated with a 3-fold increase in development of AF. Thyrotoxicosis exerts marked influences on electrical impulse generation (chronotropic effect and conduction (dromotropic effect. Several potential mechanisms could be invoked for the effect of thyroid hormones on AF risk, including elevation of left atrial pressure secondary to increased left ventricular mass and impaired ventricular relaxation, ischemia resulting from increased resting heart rate, and increased atrial eopic activity. Reentry has been postulated as one of the main mechanisms leading to AF. AF is more likely if effective refractory periods are short and conduction is slow. Hyperthyroidism is associated with shortening of action potential duration which may also contribute to AF.

  14. Atrial Fibrillation Predictors: Importance of the Electrocardiogram.

    Science.gov (United States)

    German, David M; Kabir, Muammar M; Dewland, Thomas A; Henrikson, Charles A; Tereshchenko, Larisa G

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in adults and is associated with significant morbidity and mortality. Substantial interest has developed in the primary prevention of AF, and thus the identification of individuals at risk for developing AF. The electrocardiogram (ECG) provides a wealth of information, which is of value in predicting incident AF. The PR interval and P wave indices (including P wave duration, P wave terminal force, P wave axis, and other measures of P wave morphology) are discussed with regard to their ability to predict and characterize AF risk in the general population. The predictive value of the QT interval, ECG criteria for left ventricular hypertrophy, and findings of atrial and ventricular ectopy are also discussed. Efforts are underway to develop models that predict AF incidence in the general population; however, at present, little information from the ECG is included in these models. The ECG provides a great deal of information on AF risk and has the potential to contribute substantially to AF risk estimation, but more research is needed. © 2015 Wiley Periodicals, Inc.

  15. Michler’s Hydrol Blue: A Sensitive Probe for Amyloid Fibril Detection

    KAUST Repository

    Kitts, Catherine C.; Beke-Somfai, Tamás; Nordén, Bengt

    2011-01-01

    amyloid probe, can differentiate between insulin and lysozyme fibrils by a more red-shifted excitation spectrum for insulin fibrils. To support the experimental observations, time-dependent density functional theory (TDDFT) calculations were performed

  16. Risk of atrial fibrillation as a function of the electrocardiographic PR interval

    DEFF Research Database (Denmark)

    Nielsen, Jonas Bille; Pietersen, Adrian; Graff, Claus

    2013-01-01

    Prolongation of the PR interval has been associated with an increased risk of incident atrial fibrillation (AF).......Prolongation of the PR interval has been associated with an increased risk of incident atrial fibrillation (AF)....

  17. A randomized study of the effects of exercise training on patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Osbak, Philip Samuel; Mourier, Malene; Kjaer, Andreas

    2011-01-01

    Exercise training is beneficial in ischemic and congestive heart disease. However, the effect on atrial fibrillation (AF) is unknown.......Exercise training is beneficial in ischemic and congestive heart disease. However, the effect on atrial fibrillation (AF) is unknown....

  18. Determination of collagen fibril structure and orientation in connective tissues by X-ray diffraction

    Science.gov (United States)

    Wilkinson, S. J.; Hukins, D. W. L.

    1999-08-01

    Elastic scattering of X-rays can provide the following information on the fibrous protein collagen: its molecular structure, the axial arrangement of rod-like collagen molecules in a fibril, the lateral arrangement of molecules within a fibril, and the orientation of fibrils within a biological tissue. The first part of the paper reviews the principles involved in deducing this information. The second part describes a new computer program for measuring the equatorial intensity distribution, that provides information on the lateral arrangement of molecules within a fibril, and the angular distribution of the equatorial peaks that provides information on the orientation of fibrils. Orientation of fibrils within a tissue is quantified by the orientation distribution function, g( φ), which represents the probability of finding a fibril oriented between φ and φ+ δφ. The application of the program is illustrated by measurement of g( φ) for the collagen fibrils in demineralised cortical bone from cow tibia.

  19. Long-Term Exposure to Traffic-Related Air Pollution and Risk of Incident Atrial Fibrillation

    DEFF Research Database (Denmark)

    Monrad, Maria; Sajadieh, Ahmad; Christensen, Jeppe Schultz

    2017-01-01

    BACKGROUND: Atrial fibrillation is the most common sustained arrhythmia and associated with cardiovascular morbidity and mortality. The few studies conducted on short-term effects of air pollution on episodes of atrial fibrillation indicates a positive association, though not consistently...

  20. Newer Anticoagulants for Non-Valvular Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Joseph M. Harburger

    2012-05-01

    Full Text Available Non-valvular atrial fibrillation is a recognized risk factor for stroke and systemic embolism. It has been clearly established that warfarin reduces the risk of stroke and systemic embolism in persons with atrial fibrillation and additional risk factors for stroke. The use of warfarin, however, requires frequent monitoring, and there is great variability in patient response to warfarin. Warfarin interacts with several medications and foods. In addition, warfarin use portends a significant risk of bleeding. For these reasons, warfarin is frequently not prescribed to persons for whom the drug would provide a clear benefit. Over the past decade, attempts have been made to develop drugs that are at least as safe and effective as warfarin for the treatment of atrial fibrillation that do not require monitoring nor have as many interactions. Initial studies of compounds in this regard ultimately failed due to safety concerns, but over the past two years two novel agents have been approved by the United States Food and Drug Association for anticoagulation in non-valvular atrial fibrillation, another drug is under review, and additional compounds are being studied. This article will review the use of warfarin and these new agents in the treatment of non-valvular atrial fibrillation.

  1. Heart failure and atrial fibrillation: current concepts and controversies.

    Science.gov (United States)

    Van den Berg, M. P.; Tuinenburg, A. E.; Crijns, H. J.; Van Gelder, I. C.; Gosselink, A. T.; Lie, K. I.

    1997-01-01

    Heart failure and atrial fibrillation are very common, particularly in the elderly. Owing to common risk factors both disorders are often present in the same patient. In addition, there is increasing evidence of a complex, reciprocal relation between heart failure and atrial fibrillation. Thus heart failure may cause atrial fibrillation, with electromechanical feedback and neurohumoral activation playing an important mediating role. In addition, atrial fibrillation may promote heart failure; in particular, when there is an uncontrolled ventricular rate, tachycardiomyopathy may develop and thereby heart failure. Eventually, a vicious circle between heart failure and atrial fibrillation may form, in which neurohumoral activation and subtle derangement of rate control are involved. Treatment should aim at unloading of the heart, adequate control of ventricular rate, and correction of neurohumoral activation. Angiotensin converting enzyme inhibitors may help to achieve these goals. Treatment should also include an attempt to restore sinus rhythm through electrical cardioversion, though appropriate timing of cardioversion is difficult. His bundle ablation may be used to achieve adequate rate control in drug refractory cases. PMID:9155607

  2. Elasticity in Physically Cross-Linked Amyloid Fibril Networks

    Science.gov (United States)

    Cao, Yiping; Bolisetty, Sreenath; Adamcik, Jozef; Mezzenga, Raffaele

    2018-04-01

    We provide a constitutive model of semiflexible and rigid amyloid fibril networks by combining the affine thermal model of network elasticity with the Derjaguin-Landau-Vervey-Overbeek (DLVO) theory of electrostatically charged colloids. When compared to rheological experiments on β -lactoglobulin and lysozyme amyloid networks, this approach provides the correct scaling of elasticity versus both concentration (G ˜c2.2 and G ˜c2.5 for semiflexible and rigid fibrils, respectively) and ionic strength (G ˜I4.4 and G ˜I3.8 for β -lactoglobulin and lysozyme, independent from fibril flexibility). The pivotal role played by the screening salt is to reduce the electrostatic barrier among amyloid fibrils, converting labile physical entanglements into long-lived cross-links. This gives a power-law behavior of G with I having exponents significantly larger than in other semiflexible polymer networks (e.g., actin) and carrying DLVO traits specific to the individual amyloid fibrils.

  3. Personalized and automated remote monitoring of atrial fibrillation.

    Science.gov (United States)

    Rosier, Arnaud; Mabo, Philippe; Temal, Lynda; Van Hille, Pascal; Dameron, Olivier; Deléger, Louise; Grouin, Cyril; Zweigenbaum, Pierre; Jacques, Julie; Chazard, Emmanuel; Laporte, Laure; Henry, Christine; Burgun, Anita

    2016-03-01

    Remote monitoring of cardiac implantable electronic devices is a growing standard; yet, remote follow-up and management of alerts represents a time-consuming task for physicians or trained staff. This study evaluates an automatic mechanism based on artificial intelligence tools to filter atrial fibrillation (AF) alerts based on their medical significance. We evaluated this method on alerts for AF episodes that occurred in 60 pacemaker recipients. AKENATON prototype workflow includes two steps: natural language-processing algorithms abstract the patient health record to a digital version, then a knowledge-based algorithm based on an applied formal ontology allows to calculate the CHA2DS2-VASc score and evaluate the anticoagulation status of the patient. Each alert is then automatically classified by importance from low to critical, by mimicking medical reasoning. Final classification was compared with human expert analysis by two physicians. A total of 1783 alerts about AF episode >5 min in 60 patients were processed. A 1749 of 1783 alerts (98%) were adequately classified and there were no underestimation of alert importance in the remaining 34 misclassified alerts. This work demonstrates the ability of a pilot system to classify alerts and improves personalized remote monitoring of patients. In particular, our method allows integration of patient medical history with device alert notifications, which is useful both from medical and resource-management perspectives. The system was able to automatically classify the importance of 1783 AF alerts in 60 patients, which resulted in an 84% reduction in notification workload, while preserving patient safety. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  4. Investigation of a concept for electrohydraulic power supply for future passenger car brake systems considering; Untersuchung zur Konzeption einer elektrohydraulischen Energieversorgung fuer zukuenftige Pkw-Bremssysteme

    Energy Technology Data Exchange (ETDEWEB)

    Mutschler, R.

    1999-07-01

    An electrohydraulic power supply for passenger car brake systems is presented. These systems can be classified as brake by wire. The power supply consists of a hydropneumatic accumulator, a high pressure pump and an electric drive. The components are designed considering automotive requests. A new approach to minimize hydraulic pulsations caused by a high pressure piston pump is shown. [German] Eine elektrohydraulische Energieversorgung fuer PKW-Bremssysteme wird vorgestellt. Diese Systeme koennen mit brake by wire klassifiziert werden. Die Energieversorgung besteht aus einem hydropneumatischen Speicher, einer Hochdruckpumpe und einem elektrischen Antrieb. Die Komponenten werden hinsichtlich Automobilanforderungen ausgelegt. Eine neue Methode der Minimierung hydraulischer Pulsationen, die von einer Hochdruck Kolbenpumpe verursacht werden, wird gezeigt.

  5. Observation of the efficacy of radiofrequency catheter ablation on patients with different forms of atrial fibrillation.

    Science.gov (United States)

    Zhao, R-C; Han, W; Han, J; Yu, J; Guo, J; Fu, J-L; Li, Z; Zhao, R-Z

    2016-10-01

    To study the efficacy and safety of radiofrequency catheter ablation (RFCA) in patients with different forms of atrial fibrillation. By retrospective analysis, we summarize 720 cases, where patients diagnosed with atrial fibrillation in our hospital were treated with RFCA from February 2010 to October 2014. Among the cases, 425 were diagnosed with paroxysmal atrial fibrillation and 295 with non-paroxysmal atrial fibrillation (including persistent atrial fibrillation and permanent atrial fibrillation). All patients were followed up until June 2015 to compare and analyze the differences in operation success rates, complications and recurrence rates. 395 cases (92.9%) of paroxysmal atrial fibrillation and 253 cases (85.8%) with non-paroxysmal atrial fibrillation were subject to surgery and followed up. The age of onset, disease course, underlying diseases, left atrial diameter and combined anti-arrhythmics of patients with paroxysmal atrial fibrillation were lower than those of patients with non-paroxysmal atrial fibrillation, and the differences were statistically significant (p success rate of the first ablation was higher than that of non-paroxysmal atrial fibrillation. Procedure time, procedure method, complications and recurrence rate of patients with paroxysmal atrial fibrillation were lower than those of non-paroxysmal atrial fibrillation group, and the differences were statistically significant (p failure caused by atrial fibrillation in the two groups, the difference was not statistically significant (Apoplexy: p = 0.186; Heart failure: p = 0.170). The individual ablation success rate was higher for paroxysmal atrial fibrillation, and long-term follow-up showed that the occurrence of apoplexy and heart failure was not different from the non-paroxysmal atrial fibrillation group.

  6. Modelling and simulation of an absorption cycle with a blow pump; Modellierung und Simulation eines Absorptionskreislaufes mit einer Blasenpumpe

    Energy Technology Data Exchange (ETDEWEB)

    Buecherl, Markus

    2011-07-01

    Diffusion-absorption refrigerators are commonly operated with ammonia and water. If a ionic liquid with negligible vapour pressure is substituted for water, the rectifier will be unnecessary. In the context of a diploma thesis, a diffusion-absorption refrigerator with a blower pump and ammonia and a ionic liquid as working fluid was modelled and simulated. For this, three models were selected from the relevant literature and compared. Changes in COP as a result of varied operating parameters were investigated as well. It was shown that it is possible, in principle, to operate a diffusion-absorption refrigerator with a ionic liquid. [German] Diffusions-Absorptions-Kaeltemaschinen werden in der Regel mit dem Arbeitsstoffpaar Ammoniak-Wasser betrieben. Ersetzt man das Absorptionsmittel Wasser gegen eine ionische Fluessigkeit, die nur einen vernachlaessigbaren Dampfdruck besitzt, kann man den Rektifikator einsparen. Im Rahmen einer Diplomarbeit wurde eine Diffusions-Absorptions-Kaeltemaschine mit einer Blasenpumpe und dem Arbeitsstoffpaar Ammoniak-Ionische Fluessigkeit modelliert und simuliert. Hierfuer wurden drei Modelle aus der Literatur ausgewaehlt. Diese Modelle wurden untereinander verglichen. Ausserdem wurde die Veraenderung des COP bei der Variation der Betriebsparameter fuer diese Berechnungsmodelle untersucht. Es konnte gezeigt werden, dass es prinzipiell moeglich ist, eine Diffusions-Absorptions-Kaeltemaschine mit ionischer Fluessigkeit zu betreiben.

  7. 77 FR 11121 - Scientific Information Request on Treatment of Atrial Fibrillation

    Science.gov (United States)

    2012-02-24

    ... Information Request on Treatment of Atrial Fibrillation AGENCY: Agency for Healthcare Research and Quality... Review of the Treatment of Atrial Fibrillation, which is currently being conducted by the Evidence-based... the treatment of atrial fibrillation. The EHC Program is dedicated to identifying as many studies as...

  8. 78 FR 11207 - Clinical Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation...

    Science.gov (United States)

    2013-02-15

    ...] Clinical Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation; Guidance for... devices intended for the treatment of atrial fibrillation. DATES: Submit either electronic or written... Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation'' to the Division of...

  9. SAFETY OF AMIODARONE USAGE IN PATIENTS WITH WOLFF-PARKINSON-WHITE SYNDROME AND ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    D. A. Kuzhel

    2010-01-01

    Full Text Available Amiodarone is one of the basic antiarrhytmic drugs for atrial fibrillation treatment. However application of amiodarone in patients with atrial fibrillation and Wolff-Parkinson-White syndrome can induce ventricular fibrillation. Amiodarone usage in these patients should be accompanied by readiness for performance of resuscitation. This is confirmed by clinical case presentation.

  10. Meta-analysis identifies six new susceptibility loci for atrial fibrillation

    NARCIS (Netherlands)

    Ellinor, Patrick T; Lunetta, Kathryn L; Albert, Christine M; Glazer, Nicole L; Ritchie, Marylyn D; Smith, Albert V; Arking, Dan E; Müller-Nurasyid, Martina; Krijthe, Bouwe P; Lubitz, Steven A; Bis, Joshua C; Chung, Mina K; Dörr, Marcus; Ozaki, Kouichi; Roberts, Jason D; Smith, J Gustav; Pfeufer, Arne; Sinner, Moritz F; Lohman, Kurt; Ding, Jingzhong; Smith, Nicholas L; Smith, Jonathan D; Rienstra, Michiel; Rice, Kenneth M; Van Wagoner, David R; Magnani, Jared W; Wakili, Reza; Clauss, Sebastian; Rotter, Jerome I; Steinbeck, Gerhard; Launer, Lenore J; Davies, Robert W; Borkovich, Matthew; Harris, Tamara B; Lin, Honghuang; Völker, Uwe; Völzke, Henry; Milan, David J; Hofman, Albert; Boerwinkle, Eric; Chen, Lin Y; Soliman, Elsayed Z; Voight, Benjamin F; Li, Guo; Chakravarti, Aravinda; Kubo, Michiaki; Tedrow, Usha B; Rose, Lynda M; Ridker, Paul M; Conen, David; Tsunoda, Tatsuhiko; Furukawa, Tetsushi; Sotoodehnia, Nona; Xu, Siyan; Kamatani, Naoyuki; Levy, Daniel; Nakamura, Yusuke; Parvez, Babar; Mahida, Saagar; Furie, Karen L; Rosand, Jonathan; Muhammad, Raafia; Psaty, Bruce M; Meitinger, Thomas; Perz, Siegfried; Wichmann, H-Erich; Witteman, Jacqueline C M; Kao, W H Linda; Kathiresan, Sekar; Roden, Dan M; Uitterlinden, Andre G; Rivadeneira, Fernando; McKnight, Barbara; Sjögren, Marketa; Newman, Anne B; Liu, Yongmei; Gollob, Michael H; Melander, Olle; Tanaka, Toshihiro; Stricker, Bruno H Ch; Felix, Stephan B; Alonso, Alvaro; Darbar, Dawood; Barnard, John; Chasman, Daniel I; Heckbert, Susan R; Benjamin, Emelia J; Gudnason, Vilmundur; Kääb, Stefan

    Atrial fibrillation is a highly prevalent arrhythmia and a major risk factor for stroke, heart failure and death. We conducted a genome-wide association study (GWAS) in individuals of European ancestry, including 6,707 with and 52,426 without atrial fibrillation. Six new atrial fibrillation

  11. Optimizing cellulose fibrillation for the production of cellulose nanofibrils by a disk grinder

    Science.gov (United States)

    Chuanshuang Hu; Yu Zhao; Kecheng Li; J.Y. Zhu; Roland Gleisner

    2015-01-01

    The fibrillation of a bleached kraft eucalyptus pulp was investigated by means of a laboratory-scale disk grinder for the production of cellulose nanofibrils (CNF), while the parameters disk rotating speed, solid loading, and fibrillation duration were varied. The cumulative energy consumption was monitored during fibrillation. The degree of polymerization (DP) and...

  12. Perspektiven einer Rezeption neurowissenschaftlicher Erkenntnisse in der Erziehungswissenschaft (Perspectives of an Integration of Neuro-Scientific Findings into Educational Science).

    Science.gov (United States)

    Becker, Nicole

    2002-01-01

    Sketches the status quo and possible starting points for the adoption of neuro-scientific findings by educational science. Describes the latest developments in U.S. research. Discusses the adoption of these points by German educational science. Outlines the possibilities and limits of an interdisciplinary discourse. (CAJ)

  13. Praktikum Medizinische Recherche: Erfahrungen mit einer curricular integrierten Schulungsveranstaltung / Medical Information Retrieval Training: a practical training integrated into the curriculum

    Directory of Open Access Journals (Sweden)

    Wagner, Christiane

    2006-12-01

    Full Text Available n June 2004 a course problem oriented learning (POL has been introduced at the medical faculty of the University Leipzig. The course on the topic „Infectology and Immunology“ takes place once a year and lasts for four weeks. It consists of a series of lectures and tutorials, in which small groups of students work on clinical case examples. Also part of the course are some practical training sessions. One of them is a 90 minutes practical training on searching for medical literature, which is organized by the medical library. In 2006 the practical training took place for the third time. The article tells about the development within the three years and the experiences that have been made.

  14. Disease management: atrial fibrillation and home monitoring.

    Science.gov (United States)

    Ricci, Renato Pietro

    2013-06-01

    Device-detected atrial fibrillation (AF) episodes predict poor clinical outcome regardless of symptoms. Potential benefits of remote monitoring are early arrhythmia detection and patient continuous monitoring. Several studies of device remote monitoring consistently demonstrated that AF represents the most common clinical alert and that detailed information on arrhythmia onset, duration, and burden as well as on the ventricular rate may be early available for clinical evaluation. Reaction time to AF alerts was very short in all series involving either pacemakers or defibrillators and action ability of AF alerts was very high. In the Home Guide Registry, in which 1650 patients were enrolled, AF was detected in 16.3% of patients and represented 36% of all cardiovascular events during the follow-up. Timely anticoagulation introduction in asymptomatic patients may impact on the stroke rate. According to the results of repeated Monte Carlo simulations based on a real population of 166 patients, daily monitoring may reduce the 2-year stroke risk by 9-18% with an absolute reduction of 0.2-0.6%, compared with conventional inter-visit intervals of 6-12 months. In the COMPAS trial, the incidence of hospitalizations for atrial arrhythmias and related stroke was significantly higher in the control group than in the remote monitoring group. Major questions will be addressed by the ongoing IMPACT trial in which a remote monitoring guided anticoagulation strategy based on AF detection will be compared with a physician-directed standard strategy. In patients with heart failure, AF early detection combined with other indexes may help prevent hospitalizations.

  15. Calcium signalling silencing in atrial fibrillation.

    Science.gov (United States)

    Greiser, Maura

    2017-06-15

    Subcellular calcium signalling silencing is a novel and distinct cellular and molecular adaptive response to rapid cardiac activation. Calcium signalling silencing develops during short-term sustained rapid atrial activation as seen clinically during paroxysmal atrial fibrillation (AF). It is the first 'anti-arrhythmic' adaptive response in the setting of AF and appears to counteract the maladaptive changes that lead to intracellular Ca 2+ signalling instability and Ca 2+ -based arrhythmogenicity. Calcium signalling silencing results in a failed propagation of the [Ca 2+ ] i signal to the myocyte centre both in patients with AF and in a rabbit model. This adaptive mechanism leads to a substantial reduction in the expression levels of calcium release channels (ryanodine receptors, RyR2) in the sarcoplasmic reticulum, and the frequency of Ca 2+ sparks and arrhythmogenic Ca 2+ waves remains low. Less Ca 2+ release per [Ca 2+ ] i transient, increased fast Ca 2+ buffering strength, shortened action potentials and reduced L-type Ca 2+ current contribute to a substantial reduction of intracellular [Na + ]. These features of Ca 2+ signalling silencing are distinct and in contrast to the changes attributed to Ca 2+ -based arrhythmogenicity. Some features of Ca 2+ signalling silencing prevail in human AF suggesting that the Ca 2+ signalling 'phenotype' in AF is a sum of Ca 2+ stabilizing (Ca 2+ signalling silencing) and Ca 2+ destabilizing (arrhythmogenic unstable Ca 2+ signalling) factors. Calcium signalling silencing is a part of the mechanisms that contribute to the natural progression of AF and may limit the role of Ca 2+ -based arrhythmogenicity after the onset of AF. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

  16. Clinical application of low energy intracardiac cardioversion of atrial fibrillation

    International Nuclear Information System (INIS)

    Wu Liqun; Gu Gang; Su Kan; Su Renying; Shen Yongchu; Shen Weifeng

    2002-01-01

    Objective: To evaluate the efficacy and safety of low energy intracardiac cardioversion in persistent atria fibrillation. Methods: Low energy intracardiac cardioversion was performed by delivering R wave-synchronized biphasic shocks in 7 patients (4 men, 3 women) with persistent atrial fibrillation. Prior to the procedure, all patients underwent transesophageal echocardiographic examinations to rule out the presence of intracardiac thrombus and received subcutaneous injection of low molecular weight heparin for 3-5 days. Two custom-made 6 Fr catheters (Rhythm Technologies of Getz, USA) were used for de-fibrillation shock delivery. One catheter was positioned in the lower right atrium so that the majority of the catheter electrodes had firm contact with the right atrial free wall. The second catheter was placed randomly either in coronary sinus through right internal jugular vein or in the left pulmonary artery through femoral vein. In addition, a standard diagnostic 6-F quadrupolar catheter was placed at the right ventricular apex for ventricular synchronization and postshock ventricular pacing. Shocks were delivered by Implant Support Device (Model 4510, Teleceronics). After conversion, all patients were treated with intravenous amiodarone in the first 24 hours followed by oral administration. Results: In all 7 patients cardioversion of atrial fibrillation to sinus rhythm was successfully obtained. A mean of 2 ± 1 shocks per patient has been delivered with a total amount of 13 shocks. The average delivered energy was 7.8 ± 2.2 Joules. No complication occurred. At a mean follow-up of 18 ± 9 months, 4 of the 7 patients treated successfully showed sinus rhythm there after. Atrial fibrillation recurred in 3 patients at the second, fifth day and eighth month after cardioversion. Conclusions: Low energy intracardiac cardioversion is effective and safe, and can be easily performed in patients without general anesthesia. It offers a new option for restoring sinus

  17. Failure of antiarrhythmic drugs to prevent experimental reperfusion ventricular fibrillation.

    Science.gov (United States)

    Naito, M; Michelson, E L; Kmetzo, J J; Kaplinsky, E; Dreifus, L S

    1981-01-01

    Ninety-nine adult mongrel dogs underwent acute ligation of the proximal left anterior descending coronary artery. Thirty minutes later, the occlusion was released to evaluate the effectiveness of five antiarrhythmic protocols in eliminating reperfusion ventricular fibrillation. The five protocols included: protocol 1 --i.v. lidocaine, preligation and prerelease (n = 19); protocol 2 -- i.v. lidocaine, prereperfusion only (n = 22); protocol 3 -- chronic, oral, daily amiodarone for 2 weeks preligation (n = 19); protocol 4 -- i.v. procainamide, preligation and prereperfusion (n = 21); and protocol 5 -- i.v. verapamil, prereperfusion (n = 18). Each regimen was evaluated with respect to the incidence of reperfusion ventricular fibrillation in dogs that survived to reperfusion, and the results were compared to 77 control dogs that underwent identical coronary artery occlusion and release procedures without drug therapy. The incidence of reperfusion ventricular fibrillation was as follows: protocol 1 -- seven of 15 dogs (47%); protocol 2 -- six of 18 (33%); protocol 3 -- 11 of 16 dogs (69%); protocol 4 -- eight of 17 dogs (47%); and protocol 5 -- 10 of 17 dogs (59%), compared with 36 of 60 (60%) in control dogs. Using chi-square analysis, protocol 2 was beneficial (p antecedent coronary artery ligation periods, and predictive risk indexes for the occurrence of reperfusion ventricular fibrillation were developed. the Mantel-Haenszel method of statistical analysis revealed that none of these protocols resulted in a statistically significant reduction in the incidence of reperfusion ventricular fibrillation. Thus, use of these predictive indexes plus appropriate statistical methods has revealed, unexpectedly, limitations in the efficacy of a spectrum of antiarrhythmic agents in preventing reperfusion ventricular fibrillation.

  18. Exposure-Based Therapy for Symptom Preoccupation in Atrial Fibrillation

    DEFF Research Database (Denmark)

    Särnholm, Josefin; Skúladóttir, Helga; Rück, Christian

    2017-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia. Patients often experience a range of symptoms resulting in a markedly reduced quality of life, and commonly show symptom preoccupation in terms of avoidance and control behaviors. Cognitive behavior therapy (CBT) has been shown...... with symptomatic paroxysmal (intermittent) atrial fibrillation who were assessed pre- and posttreatment and at 6-month follow-up. The CBT lasted 10 weeks and included exposure to physical sensations similar to AF symptoms, exposure to avoided situations or activities, and behavioral activation. We observed large...

  19. SDS-Induced Fibrillation of α-Synuclein

    DEFF Research Database (Denmark)

    Giehm, L.; Oliveira, Cristiano Luis Pinto De; Pedersen, J.S.

    2010-01-01

    . In this fibrillogenic complex, 4 αSN molecules initially associate with 40-50 SDS molecules to form a shared micelle that gradually grows in size. The complex initially exhibits a mixture of random coil and α-helix, but incubation results in a structural conversion into β-sheet structure and concomitant formation......-stabilized micelles. Thus, fibrillation in this case occurs by a process of continuous accretion rather than by the rate-limiting accumulation of a distinct nucleus. The morphology of the SDS-induced fibrils does not exhibit the classical rod-like structures formed by αSN when aggregated by agitation in the absence...

  20. Gender Differences in Antithrombotic Treatment for Newly Diagnosed Atrial Fibrillation

    DEFF Research Database (Denmark)

    Mazurek, Michał; Huisman, Menno V; Rothman, Kenneth J

    2018-01-01

    was -0.5% (95% CI, -1.8%, 0.8%). VKAs were prescribed to 32.8% and 31.9% (NOACs 46.8% and 48.3%) of women and men, respectively. No confounder for the association between gender and anticoagulant prescription was identified. Between-gender differences in anticoagulant use (lower use in women compared......AIMS: Data on gender differences in oral anticoagulation for stroke prevention in patients with atrial fibrillation are conflicting, largely limited to regional reports and Vitamin K antagonist (VKA) use. We aimed to analyze gender-specific anticoagulant prescription patterns early following...... atrial fibrillation (difference in prevalence of anticoagulant use...

  1. New fluorescent probes for detection and characterization of amyloid fibrils

    Science.gov (United States)

    Gorbenko, Galyna; Trusova, Valeriya; Kirilova, Elena; Kirilov, Georgiy; Kalnina, Inta; Vasilev, Aleksey; Kaloyanova, Stefka; Deligeorgiev, Todor

    2010-08-01

    The applicability of the novel fluorescent probes, aminoderivative of benzanthrone ABM, squaraine dye SQ-1 and polymethine dye V2 to identification and structural analysis of amyloid fibrils has been evaluated using the lysozyme model system in which fibrillar aggregates have been formed in concentrated ethanol solution. The association constant, binding stoichiometry and molar fluorescence of the bound dye have been determined. ABM was found to surpass classical amyloid marker ThT in the sensitivity to the presence of fibrillar aggregates. Resonance energy transfer measurements involving ABM-SQ-1 and SQ-1-V2 donor-acceptor pairs yielded the limits for fractal-like dimension of lysozyme fibrils.

  2. Nearly reversible conformational change of amyloid fibrils as revealed by pH-jump experiments.

    Science.gov (United States)

    Yamaguchi, Kei-ichi; Kamatari, Yuji O; Fukuoka, Mayuko; Miyaji, Reiji; Kuwata, Kazuo

    2013-10-01

    pH-jump induced conformational transitions between substates of preformed amyloid fibrils made by a fragmented peptide of helix 2 (H2 peptide) of MoPrP were detected, and their kinetics were analyzed using a novel pH-jump apparatus specially designed for observing amyloids. Previously, we reported that H2 peptide formed ordered fibrils with a minimum at 207 nm on CD spectra at pH 2.9 (named pH 2.9 fibrils), but formed aggregate-like fibrils with a minimum at 220 nm at pH 7.5 (named pH 7.5 fibrils). When pH-jump from 2.9 to 7.5 was performed, the CD spectrum changed instantly, but the finally observed ellipticities were clearly distinct from those of pH 7.5 fibrils. Thus, the finally observed state is termed 'pH 7.5-like fibrils'. However, pH 7.5-like fibrils reverted to the conformation very similar to that of the pH 2.9 fibrils when the pH of the solution was restored to 2.9. Then, we examined the kinetics of the nearly reversible conformational changes between pH 2.9 fibrils and pH 7.5-like fibrils using ANS fluorescence stopped-flow, and we observed relatively fast phases (0.7-18 s(-1)). In contrast, the conversion between pH 7.5-like fibrils and pH 7.5 fibrils never occurred (<0.2 day(-1)). Thus, H2 fibrils can be switched readily between distinct conformations separated by a low energy barrier, while a large energy barrier clearly separated the different conformations. These conformational varieties of amyloid fibrils may explain the physical basis of the diversity in prion.

  3. Nanoscale Structure of Type I Collagen Fibrils: Quantitative Measurement of D-spacing

    Science.gov (United States)

    Erickson, Blake; Fang, Ming; Wallace, Joseph M.; Orr, Bradford G.; Les, Clifford M.; Holl, Mark M. Banaszak

    2012-01-01

    This paper details a quantitative method to measure the D-periodic spacing of Type I collagen fibrils using Atomic Force Microscopy coupled with analysis using a 2D Fast Fourier Transform approach. Instrument calibration, data sampling and data analysis are all discussed and comparisons of the data to the complementary methods of electron microscopy and X-ray scattering are made. Examples of the application of this new approach to the analysis of Type I collagen morphology in disease models of estrogen depletion and Osteogenesis Imperfecta are provided. We demonstrate that it is the D-spacing distribution, not the D-spacing mean, that showed statistically significant differences in estrogen depletion associated with early stage Osteoporosis and Osteogenesis Imperfecta. The ability to quantitatively characterize nanoscale morphological features of Type I collagen fibrils will provide important structural information regarding Type I collagen in many research areas, including tissue aging and disease, tissue engineering, and gene knock out studies. Furthermore, we also envision potential clinical applications including evaluation of tissue collagen integrity under the impact of diseases or drug treatments. PMID:23027700

  4. Circadian variation in dominant atrial fibrillation frequency in persistent atrial fibrillation

    International Nuclear Information System (INIS)

    Sandberg, Frida; Stridh, Martin; Sörnmo, Leif; Bollmann, Andreas; Husser, Daniela

    2010-01-01

    Circadian variation in atrial fibrillation (AF) frequency is explored in this paper by employing recent advances in signal processing. Once the AF frequency has been estimated and tracked by a hidden Markov model approach, the resulting trend is analyzed for the purpose of detecting and characterizing the presence of circadian variation. With cosinor analysis, the results show that the short-term variations in the AF frequency exceed the variation that may be attributed to circadian. Using the autocorrelation method, circadian variation was found in 13 of 18 ambulatory ECG recordings (Holter) acquired from patients with long-standing persistent AF. Using the ensemble correlation method, the highest AF frequency usually occurred during the afternoon, whereas the lowest usually occurred during late night. It is concluded that circadian variation is present in most patients with long-standing persistent AF though the short-term variation in the AF frequency is considerable and should be taken into account

  5. Three-dimensional mathematical modelling of a proton-exchange membrane fuel cell (PEMFC); Dreidimensionale mathematische Modellierung einer Brennstoffzelle mit Protonen-Austausch-Membran (PEMFC)

    Energy Technology Data Exchange (ETDEWEB)

    Mosig, J

    1997-12-01

    The use of proton-exchange membrane fuel cells (PEMFC) in motor vehicles is being explored worldwide and demonstrated in prototypes. The structural improvement of the cells requires an in-depth understanding of the physiochemical processes taking place in the interior. Mathematical simulations can considerably contribute to providing this understanding. In the present study, a mathematical model is presented which enables the calculation of mass and charge flows in the different material layers of a rectangular, planar PEM fuel cell and provides the corresponding three-dimensional concentration and potential distributions. The simulation software permits the steady-state and isothermal calculation of hydrogen/air single cells to which fuel and oxidant can be fed in a co-flow, counter-flow or cross-flow configuration. The mathematical solution method is based on the finite integration technique. The large, sparse systems of equations resulting from the discretization of the conservation equations are very efficiently solved using a multigrid method. A comparison of calculated current-density/voltage characteristics for a base-case cell with measured current-density/voltage characteristics confirms the good quality of the simulation results. Parameter variations show the dependence of the electrode kinetics on the cell temperature and on the gas pressures of the fuel and air side. Furthermore, the influence of the pressure difference between fuel and oxidant on the water regime of the electrolyte membrane is examined. Finally, simulation calculations for different fuel cell materials and ratios of gas-channel to ridge width show the influence of structural fuel cell parameters on the performance of a PEM fuel cell. (orig.) [Deutsch] Der Einsatz von Brennstoffzellen mit Protonen-Austausch-Membran (PEMFC) in Kraftfahrzeugen wird weltweit erforscht und in Prototypen demonstriert. Ihre konstruktive Verbesserung erfordert ein tiefes Verstaendnis der im Inneren ablaufenden

  6. Analysis of brain natriuretic peptide in 30 patients with atrial fibrillation

    International Nuclear Information System (INIS)

    Jin Qiang; Lu Jianghui; Li Weipeng; Yuan Yuan; Sun Weili

    2009-01-01

    To investigate the relationship between atrial fibrillation and brain natriuretic peptide (BNP), plasma levels of BNP in 30 patients with atrial fibrillation and 30 health controls were assayed and compared. The results showed that plasma levels of BNP in patients with atrial fibrillation were significantly higher than those of health controls (P<0.05). When the patients with atrial fibrillation were restored sinus rhythm, the concentration of BNP decreased significantly (P<0.05). BNP was a sensitive marker of cardiac dysfunction, and BNP was positively correlated with atrial fibrillation. (authors)

  7. Ukrainische Musik. Idee und Geschichte einer musikalischen Nationalbewegung in ihrem europäischen Kontext, Lipsko, 7.-9. května 2006

    Czech Academy of Sciences Publication Activity Database

    Bajgarová, Jitka

    2006-01-01

    Roč. 43, č. 2 (2006), s. 215-216 ISSN 0018-7003. [Ukrainische Musik . Idee und Geschichte einer musik alischen Nationalbewegung in ihrem europäischen Kontext. Lipsko, 07052006-09052006] Institutional research plan: CEZ:AV0Z90580513 Keywords : Ukrainian music culture * European context Subject RIV: AL - Art, Architecture, Cultural Heritage

  8. [Anja Wilhelmi, Menschenbilder aus Reval und St. Peterburg. Reiseeindrücke einer Engländerin um 1840] / Paul Kaegbein

    Index Scriptorium Estoniae

    Kaegbein, Paul

    2006-01-01

    Arvustus: Anja Wilhelmi, Menschenbilder aus Reval und St. Peterburg. Reiseeindrücke einer Engländerin um 1840. In: Kollektivität und Individualität. Hamburg: Kovaè, 2001. S. 224-242. Elizabeth Rigby 1840. aastal Londonis anonüümselt ilmunud raamatust "Letters from the shores of the Baltic"

  9. Anatomy of the fingers in MR imaging using a high resolution surface coil; Die Anatomie der Finger in der MRT unter Anwendung einer Hochaufloesungsspule

    Energy Technology Data Exchange (ETDEWEB)

    Maeurer, J. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Mueller, H.F. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Lemke, A.J. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Requardt, R. [Siemens AG, Erlangen (Germany); Stein, I. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Schedel, H. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Langer, R. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany); Felix, R. [Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Standort Wedding, Freie Univ. Berlin (Germany)

    1994-12-31

    MR-images of the fingers of twenty healthy volunteers were obtained at a 1,5-T whole-body system with a high resolution coil. Additionally, the fingers of two formalin-fixed anatomical specismen were imaged, fronzen and then subsequently sectioned for anatomic correlation. Measurements were recorded with a slice thickness of 2 mm. A 256x256 matrix and a 2,5 cam fiel of view (FOV) were used resulting in a pixel size of 0,01 mm{sup 2}. Based on the excellent depiction of anatomic detail and contrast resolution high resolution MRI of the fingers enabled identification of osseous and cartilaginous structures, as well as delineation of tendons, ligaments blood-vessels and dermal layers. (orig.) [Deutsch] An einem 1,5-T-Ganzkoerpertomographen wurden die Finger von 20 gesunden Probanden mit einer Hochaufloesungsspule zur Darstellung der Anatomie untersucht. Zum Vergleich erfolgte die Abbildung der anatomischen Strukturen an zwei formol- und alkoholfixierten Leichepraeparaten der Hand mittels MRT. Im Anschluss wurden die untersuchten Regionen am tiefgefrorenen Praeparat mit einer Bandsaege nachgeschnitten. Die MR-Messungen wurden mit einer Schichtdicke von 3 mm, einem Field of View (FOV) von 25 mm und einer Matrix von 256x256 Pixel durchgefuehrt. Die daraus resultierende Pixelgroesse betrug 0,01 mm{sup 2}. Der Weichteilkontrast und die hohe Ortsaufloesung ermoeglichten die Identifikation von Knochen- und Knorpelstrukturen sowie die Abgrenzung von Sehnen, Baendern, Blutgefaessen und Hautschichten. (orig.)

  10. [Antjekathrin Grassmann. Zu den wirtschaftlichen und persönlichen Beziehungen Lübecks ins Baltikum im Lichte einer unbeachteten mittelalterlichen Quellegruppe]/ Dennis Hortmuth

    Index Scriptorium Estoniae

    Hormuth, Dennis

    2012-01-01

    Arvustus: Antjekathrin Grassmann. Zu den wirtschaftlichen und persönlichen Beziehungen Lübecks ins Baltikum im Lichte einer unbeachteten mittelalterlichen Quellegruppe. In: Leder ist Brot. Beiträge zur norddeutschen Landes- und Archivgeseten. Schwerin 2011. S. 125-135

  11. Ventricular fibrillation development following atrial fibrillation after the ingestion of sildenaphil in a patient with Wolff-Parkinson-White syndrome.

    Science.gov (United States)

    Inci, Sinan; Izgu, Ibrahim; Aktas, Halil; Dogan, Pinar; Dogan, Ali

    2015-08-01

    Complications in the accessory pathway in Wolff-Parkinson-White (WPW) syndrome could cause different clinical conditions by inducing different arrhythmias. Atrial fibrillation (AF) is one of these arrhythmias and is important as it causes life-threatening arrhythmias. It is known that some drugs, underlying cardiac diseases, and the number of accessory pathways, cause a predisposition to this condition. In the current report, we presented a patient with WPW who was admitted to the emergency department with AF, wide QRS and a rapid ventricular response that progressed to ventricular fibrillation.

  12. Planung einer Mobile Learning Application für medizinische Lerninhalte [Planning of a mobile learning application for medical contents

    Directory of Open Access Journals (Sweden)

    Walther, Patrick

    2013-11-01

    Full Text Available [english] Due to the high popularity of mobile devices barriers for mobile learning are becoming less. Place-and time-independent access to information is part of everyday life. The number of mobile applications is steadily growing. Currently there are more than 500,000 mobile applications, so-called apps, available for the Apple iPhone/iPad which can be downloaded in the Apple iTunes Store. More than ten percent of these apps are mobile learning applications.Before starting development of a mobile app we need to analyze all requirements accurately. This is due to the fact that there is a multiplicity of different operating systems with different functionalities. This paper shows general properties of so-called native, hybrid, and web applications and advantages and disadvantages in development and use of the finished application. In addition, current software, which supports the development of a mobile application is explained.Finally the differences of the various development options are shown based on concrete mobile applications.[german] Aufgrund der hohen Verbreitung mobiler Endgeräte werden die Barrieren für das mobile Lernen immer geringer und orts- und zeitunabhängiger Zugriff auf Informationen ist längst im Alltag angekommen. Die Zahl mobiler Applikation wächst stetig an. So stehen beispielsweise aktuell mehr als 500.000 mobile Applikationen, sogenannte Apps, für das Apple iPhone/iPad, dem Nutzer über den Apple iTunes Store bereit. Hiervon sind mehr als zehn Prozent mobile Lernapplikationen.Vor der eigentlichen Entwicklung einer App muss, u.a. aufgrund der Vielzahl mobiler Betriebssysteme und Funktionen der verschiedenen mobilen Endgeräte, zuvor eine genaue Bedarfsanalyse durchgeführt werden um die passende Entwicklungsvariante zu wählen.In diesem Beitrag werden die verschiedenen Möglichkeiten (nativ, hybrid, web zur Entwicklung einer mobilen Applikation, als auch deren Vor- und Nachteile bei der Entwicklung und Nutzung der

  13. Fibril morphology and tendon mechanical properties in patellar tendinopathy: effects of heavy slow resistance training

    DEFF Research Database (Denmark)

    Kongsgaard, Mads; Qvortrup, Klaus; Larsen, Jytte Overgaard

    2010-01-01

    BACKGROUND: Patellar tendinopathy is characterized by pathologic abnormalities. Heavy slow resistance training (HSR) is effective in the management of patellar tendinopathy, but the underlying functional mechanisms remain elusive. PURPOSE: To investigate fibril morphology and mechanical properties...... assessed symptoms/function and maximal tendon pain during activity. Tendon biopsy samples were analyzed for fibril density, volume fraction, and mean fibril area. Tendon mechanical properties were assessed using force and ultrasonography samplings. RESULTS: Patients improved in symptoms/function (P = .02...... area decreased (-26% +/- 21%, P = .04) in tendinopathic tendons after HSR. CONCLUSION: Fibril morphology is abnormal in tendinopathy, but tendon mechanical properties are not. Clinical improvements after HSR were associated with changes in fibril morphology toward normal fibril density and mean fibril...

  14. Embolic risk in atrial fibrillation that arises from hyperthyroidism: review of the medical literature.

    Science.gov (United States)

    Traube, Elie; Coplan, Neil L

    2011-01-01

    Atrial fibrillation, the most common cardiac complication of hyperthyroidism, occurs in an estimated 10% to 25% of overtly hyperthyroid patients. The prevalence of atrial fibrillation increases with age in the general population and in thyrotoxic patients. Other risk factors for atrial fibrillation in thyrotoxic patients include male sex, ischemic or valvular heart disease, and congestive heart failure. The incidence of arterial embolism or stroke in thyrotoxic atrial fibrillation is less clear. There are many reports of arterial thromboembolism associated with hyperthyroidism, including cases of young adults without coexisting risk factors other than thyrotoxic atrial fibrillation. The use of anticoagulative agents to prevent thromboembolic sequelae of thyrotoxic atrial fibrillation is controversial: National organizations provide conflicting recommendations in their practice guidelines. Herein, we review the medical literature and examine the evidence behind the recommendations in order to determine the best approach to thromboembolic prophylaxis in patients who have atrial fibrillation that is associated with hyperthyroidism.

  15. Evaluation einer elektronisch unterstützten pflegerischen Überleitung zwischen Krankenhaus und Pflegeheim unter Nutzung einer Test-Telematikinfrastruktur: eine Fallanalyse

    Directory of Open Access Journals (Sweden)

    Schulte, Georg

    2017-10-01

    Full Text Available Background: Improper information transmission can lead to compromised patient safety and quality of life when patients are transferred from one setting to another. Electronic instruments may improve this situation, however, they are rarely used. Objective: The aim of this study therefore was to investigate the technical and organizational feasibility, usability, usefulness and completeness of an electronic instrument that is based on the German HL7 CDA standard for eNursing Summaries.Materials and methods: To this end, a test health telematics infrastructure, which included the German electronic health card, was established and nursing summary application was developed that allowed summary documents to be communicated between a hospital and a nursing home. The users were asked to evaluate the usability of the nursing summary application as well as to compare the usefulness and completeness of electronically and paper transmitted information.Results: This study demonstrated the feasibility of implementing an electronic nursing summary application that was based on the German HL7 CDA standard eNursing Summary and that was integrated in a test health telematics infrastructure. It could also be shown that the users rated this application as usable and that electronically supported patient transfers were superior to paper based ones. The use of the German electronic health card was regarded as a barrier by the users.Discussion: This study emphasizes the feasibility, relevance and barriers of electronically supported transfers of patients with nursing needs. Nurses working in hospitals and long-term care can integrate an application based on the HL7 CDA Standard ePfgebericht into their working processes and get better and more complete information. To ensure continuity of care in a sustainable manner in the future, the German HL7 CDA based eNursing Summary standard should become part of the German telematics infrastructure.

  16. Postoperative atrial fibrillation in patients on statins undergoing ...

    African Journals Online (AJOL)

    Introduction: The efficacy of perioperative statin therapy in decreasing postoperative morbidity in patients undergoing valve replacements and repairs is unknown. The aim of our study was to determine whether or not the literature supports the hypothesis that statins decrease postoperative atrial fibrillation (AF), and hence ...

  17. Atrial Fibrillation in Embolic Stroke: Anticoagulant Therapy at UNTH ...

    African Journals Online (AJOL)

    Objective: The decision to commence anticoagulation in a patient with embolic stroke and atrial fibrillation (AF) is often a difficult one for many clinicians. The result can have significant impact on the patient. This study was therefore undertaken to review the use of anticoagulation in embolic stroke in the setting of atrial ...

  18. Frequency analysis of the ECG before and during ventricular fibrillation

    NARCIS (Netherlands)

    Herbschleb, J.N.; Heethaar, R.M.; Tweel, I. van der; Meijler, F.L.

    1980-01-01

    Frequency analysis of cardiac electrograms of dogs with ventricular fibrillation (VF) during complete cardiopulmonary bypass and coronary perfusion showed a power spectrum with a peak around 12 Hz and its higher harmonics, suggesting more organization than generally assumed. As a next step to see

  19. Occlusion of left atrial appendage in patients with atrial fibrillation

    Directory of Open Access Journals (Sweden)

    О. Н. Ганеева

    2015-10-01

    Full Text Available The article reviews a new method of prophylaxis of thromboembolitic complications, specifically occlusion of left atrial appendage, in patients with atrial fibrillation. Indications and contraindications for the procedure, as well as a step-by-step process of the intervention itself are described. Special emphasis is placed on the up-to-date evidence and the review of clinical trials.

  20. Abnormal atrial activation in young patients with lone atrial fibrillation

    DEFF Research Database (Denmark)

    Holmqvist, Fredrik; Olesen, Morten S; Tveit, Arnljot

    2011-01-01

    Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal hearts....

  1. Cancer antigen-125 and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Cheung, Angel; Gong, Mengqi; Bellanti, Roberto

    2018-01-01

    Background: Cancer antigen-125 (Ca-125) is traditionally recognised as a tumour marker and its role in cardiovascular diseases has been studied only in recent years. Whether Ca-125 is elevated in patients with atrial fibrillation (AF) and its levels predict the risk of AF remains controversial. T...

  2. Fibril Formation from Pea Protein and Sesequent Gel Formation

    NARCIS (Netherlands)

    Munialo, C.D.; Martin, A.H.; Linden, van der E.; Jongh, de H.H.J.

    2014-01-01

    The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20

  3. Fibril Formation from Pea Protein and Subsequent Gel Formation

    NARCIS (Netherlands)

    Munialo, XC.D.; Martin, A.H.; Linden, E. van der; Jongh, H.H.J de

    2014-01-01

    The objective of this study was to characterize fibrillar aggregates made using pea proteins, to assemble formed fibrils into protein-based gels, and to study the rheological behavior of these gels. Micrometer-long fibrillar aggregates were observed after pea protein solutions had been heated for 20

  4. P-wave duration and the risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Nielsen, Jonas B; Kühl, Jørgen T; Pietersen, Adrian

    2015-01-01

    BACKGROUND: Results on the association between P-wave duration and the risk of atrial fibrillation (AF) are conflicting. OBJECTIVE: The purpose of this study was to obtain a detailed description of the relationship between P-wave duration and the risk of AF. METHODS: Using computerized analysis o...

  5. Paroxysmal Atrial Fibrillation in a Mission-Assigned Astronaut

    Science.gov (United States)

    Bauer, Peter A.; Polk, J. D.

    2010-01-01

    This presentation will explore the clinical and administrative conundrums faced by the flight surgeon upon discovering asymptomatic paroxysmal atrial fibrillation seven months prior to scheduled long duration spaceflight. The presenter will discuss the decision-making process as well as the clinical and operational outcomes.

  6. Molecular Mechanisms and New Treatment Paradigm for Atrial Fibrillation.

    Science.gov (United States)

    Sirish, Padmini; Li, Ning; Timofeyev, Valeriy; Zhang, Xiao-Dong; Wang, Lianguo; Yang, Jun; Lee, Kin Sing Stephen; Bettaieb, Ahmed; Ma, Sin Mei; Lee, Jeong Han; Su, Demetria; Lau, Victor C; Myers, Richard E; Lieu, Deborah K; López, Javier E; Young, J Nilas; Yamoah, Ebenezer N; Haj, Fawaz; Ripplinger, Crystal M; Hammock, Bruce D; Chiamvimonvat, Nipavan

    2016-05-01

    Atrial fibrillation represents the most common arrhythmia leading to increased morbidity and mortality, yet, current treatment strategies have proven inadequate. Conventional treatment with antiarrhythmic drugs carries a high risk for proarrhythmias. The soluble epoxide hydrolase enzyme catalyzes the hydrolysis of anti-inflammatory epoxy fatty acids, including epoxyeicosatrienoic acids from arachidonic acid to the corresponding proinflammatory diols. Therefore, the goal of the study is to directly test the hypotheses that inhibition of the soluble epoxide hydrolase enzyme can result in an increase in the levels of epoxyeicosatrienoic acids, leading to the attenuation of atrial structural and electric remodeling and the prevention of atrial fibrillation. For the first time, we report findings that inhibition of soluble epoxide hydrolase reduces inflammation, oxidative stress, atrial structural, and electric remodeling. Treatment with soluble epoxide hydrolase inhibitor significantly reduces the activation of key inflammatory signaling molecules, including the transcription factor nuclear factor κ-light-chain-enhancer, mitogen-activated protein kinase, and transforming growth factor-β. This study provides insights into the underlying molecular mechanisms leading to atrial fibrillation by inflammation and represents a paradigm shift from conventional antiarrhythmic drugs, which block downstream events to a novel upstream therapeutic target by counteracting the inflammatory processes in atrial fibrillation. © 2016 American Heart Association, Inc.

  7. Atrial fibrillation: Therapeutic potential of atrial K+ channel blockers.

    Science.gov (United States)

    Ravens, Ursula; Odening, Katja E

    2017-08-01

    Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K + ) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I Kur , the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I K,ACh , the Ca 2+ -activated K + channels of small conductance (SK) conducting I SK , and the two pore domain K + (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents I TWIK-1 , I TASK-1 , and I TASK-3 . Here, we briefly review the characteristics of these K + channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Posibilities of cardiac pacemaker use in paroxsysmal atrial fibrilation

    Directory of Open Access Journals (Sweden)

    Borut Kamenik

    2005-12-01

    Full Text Available Background: Prevention of atrial fibrillation is a big therapeutic challenge because of all known negative consequences of this the most frequent cardiac arrhythmia. Numerous of clinical studies showed bad control or ineffectiveness of antiarhythmic drugs. Nonfarmakological therapies like surgical treatment, radiofrequency ablation and atrial pacing are being tested. Effectiveness of atrial pacing in prevention of paroxysmal artial fibrillation has been documented in numerous prospective studies and is effective for a long time interval, but only for patients with bradicardic underlying cardiac rhythm. In Normocardic rhythm or normal AV conduction the effective Atrial fibrillation prevention was not proven. The mechanism of action is based on premature atrial complex suppression, reduction of dispersion of refractoriness after short-long cycles and reduction of interatrial conduction delay. The atrial stimulation site or multi-site atrial pacing could be effective in AF prevention when interatrial conduction delay is present; otherwise the difference is not significant.Conclusions: In bradicardic patient who has frequent paroxysms of atrial fibrillation, regardless if bradycardia is due to ineffective antiarrhythmic drug treathement, implantation of DDDR pacemaker with atrial prevention algorhythm is indicated. If the P-wave duration is >120 milliseconds multi-site atrial pacing or septal atrial pacing should be considered. Pacemaker diagnostic tools could be used for adequate start of anticoagulant therapy and control of effectiveness of anthyarhythmic drug therapy.

  9. Pattern of atrial fibrillation and risk of outcomes

    DEFF Research Database (Denmark)

    Banerjee, Amitava; Taillandier, Sophie; Olesen, Jonas Bjerring

    2012-01-01

    BACKGROUND: Risk of stroke and thromboembolism (TE) in patients with non-valvular atrial fibrillation (NVAF) is categorised in stroke risk stratification scores. The role of pattern of NVAF in risk prediction is unclear in contemporary 'real world' cohorts. METHODS AND RESULTS: Patients with NVAF...

  10. Effect of Mechanical Stretching of the Skin on Collagen Fibril ...

    African Journals Online (AJOL)

    Dell

    MATERIALS AND METHODS. In vitro Skin Incubation. Samples of tissue were .... experimentally obtained melting curves. Calculation of the entropy of denaturation was ... Temperature (TD), enthalpy (ΔH) and entropy (ΔS) of denaturation of fibrils formed from type I collagen synthesized in the skin in the absence of tensile ...

  11. Outcomes Associated With Familial Versus Nonfamilial Atrial Fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Olesen, Jonas Bjerring; Staerk, Laila

    2016-01-01

    BACKGROUND: We examined all-cause mortality and long-term thromboembolic risk (ischemic stroke, transient ischemic attack, systemic thromboembolism) in patients with and without familial atrial fibrillation (AF). METHODS AND RESULTS: Using Danish nationwide registry data, we identified all patients...

  12. Ebstein's anomaly as a cause of paroxysmal atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Damjanović Miodrag R.

    2008-01-01

    Full Text Available Background. Ebstein's anomaly is characterized by a displacement of the tricuspid valve toward apex, because of anomalous attachment of the tricuspid leaflets. There are type B of Wolff-Parkinson-White (WPW syndrome and paroxysmal arrhythmias in more than a half of all patients. Case report. We presented a female, 32-year old, with frequent paroxysms of atrial fibrillation. After conversion of rhythm an ECG showed WPW syndrome. Echocardiographic examination discovered normal size of the left cardiac chambers with paradoxical ventricular septal motion. The right ventricle was very small because of its atrialization. The origin of the tricuspid valve was 20 mm closer to apex of the right ventricle than the origin of the mitral valve. Electrophysiological examination showed a posterolateral right accesorial pathway. Atrial fibrillation was induced very easily in electrophysiological laboratory and a successful ablation of accessorial pathway was made. There were no WPW syndrome and paroxysms of atrial fibrillation after that. Conclusion. Ebstein's anomaly is one of the reasons of paroxysmal atrial fibrillation, especially in young persons with WPW syndrome.

  13. Apixaban versus warfarin in patients with atrial fibrillation

    NARCIS (Netherlands)

    Granger, C.B.; Alexander, J.H.; McMurray, J.J.; Lopes, R.D.; Hylek, E.M.; Hanna, M.; Al-Khalidi, H.R.; Ansell, J.; Atar, D.; Avezum, A.; Bahit, M.C.; Diaz, R.; Easton, J.D.; Ezekowitz, J.A.; Flaker, G.; Garcia, D.; Geraldes, M.; Gersh, B.J.; Golitsyn, S.; Goto, S.; Hermosillo, A.G.; Hohnloser, S.H.; Horowitz, J.; Mohan, P.; Jansky, P.; Lewis, B.S.; Lopez-Sendon, J.L.; Pais, P.; Parkhomenko, A.; Verheugt, F.W.A.; Zhu, J.; Wallentin, L.

    2011-01-01

    BACKGROUND: Vitamin K antagonists are highly effective in preventing stroke in patients with atrial fibrillation but have several limitations. Apixaban is a novel oral direct factor Xa inhibitor that has been shown to reduce the risk of stroke in a similar population in comparison with aspirin.

  14. Hospitalisation patterns change over time in patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Fristrup Qvist, Janne; Høgh Sørensen, Pernille; Dixen, Ulrik

    2014-01-01

    INTRODUCTION: Atrial fibrillation (AF) is a cardiac epidemic. In this study, we aimed to describe the causes of hospital-isation in an AF population over time and to study how different AF treatment strategies affected hospitalization. MATERIAL AND METHODS: This was an observational study in which...

  15. Ganglion Plexus Ablation in Advanced Atrial Fibrillation: The AFACT Study

    NARCIS (Netherlands)

    Driessen, Antoine H. G.; Berger, Wouter R.; Krul, Sébastien P. J.; van den Berg, Nicoline W. E.; Neefs, Jolien; Piersma, Femke R.; Chan Pin Yin, Dean R. P. P.; de Jong, Jonas S. S. G.; van Boven, WimJan P.; de Groot, Joris R.

    2016-01-01

    Patients with long duration of atrial fibrillation (AF), enlarged atria, or failed catheter ablation have advanced AF and may require more extensive treatment than pulmonary vein isolation. The aim of this study was to investigate the efficacy and safety of additional ganglion plexus (GP) ablation

  16. Evalutating Inward Rectifier Current Inhibiton for Treatment of Atrial Fibrillation

    NARCIS (Netherlands)

    Ji, Yuan

    2017-01-01

    Atrial Fibrillation (AF) is one of the most common forms of cardiac arrhythmia and affects a large percentage of the human population, especially in the elderly. Currently, more than 6 million Europeans suffer from AF, and due to ageing this number will at least double in the next 50 years.

  17. Dabigatran versus warfarin in patients with atrial fibrillation

    NARCIS (Netherlands)

    Connolly, Stuart J.; Ezekowitz, Michael D.; Yusuf, Salim; Eikelboom, John; Oldgren, Jonas; Parekh, Amit; Pogue, Janice; Reilly, Paul A.; Themeles, Ellison; Varrone, Jeanne; Wang, Susan; Alings, Marco; Xavier, Denis; Zhu, Jun; Diaz, Rafael; Lewis, Basil S.; Darius, Harald; Diener, Hans-Christoph; Joyner, Campbell D.; Wallentin, Lars; Connolly, S. J.; Ezekowitz, M. D.; Yusuf, S.; Eikelboom, J.; Oldgren, J.; Parekh, A.; Reilly, P. A.; Themeles, E.; Varrone, J.; Wang, S.; Palmcrantz-Graf, E.; Haehl, M.; Wallentin, L.; Alings, A. M. W.; Amerena, J. V.; Avezum, A.; Baumgartner, I.; Brugada, J.; Budaj, A.; Caicedo, V.; Ceremuzynski, L.; Chen, J. H.; Commerford, P. J.; Dans, A. L.; Darius, H.; Di Pasquale, G.; Diaz, R.; Erol, C.; Ferreira, J.; Flaker, G. C.; Flather, M. D.; Franzosi, M. G.; Gamboa, R.; Golitsyn, S. P.; Gonzalez Hermosillo, J. A.; Halon, D.; Heidbuchel, H.; Hohnloser, S. H.; Hori, M.; Huber, K.; Jansky, P.; Kamensky, G.; Keltai, M.; Kim, S.; Lau, C. P.; Le Heuzey, J. Y. F.; Lewis, B. S.; Liu, L. S.; Nanas, J.; Razali, O.; Pais, P. S.; Parkhomenko, A. N.; Pedersen, K. E.; Piegas, L. S.; Raev, D.; Simmers, T. A.; Smith, P. J.; Talajic, M.; Tan, R. S.; Tanomsup, S.; Toivonen, L.; Vinereanu, D.; Xavier, D.; Zhu, J.; Diener, H. C.; Joyner, C. D.; Diehl, A.; Ford, G.; Robinson, M.; Silva, J.; Sleight, P.; Wyse, D. G.; Collier, J.; de Mets, D.; Hirsh, J.; Lesaffre, E.; Ryden, L.; Sandercock, P.; Anastasiou-Nana, M. I.; Andersen, G.; Annex, B. H.; Atra, M.; Bornstein, N. M.; Boysen, G.; Brouwers, P. J. A. M.; Buerke, M.; Burrell, L. M.; Chan, Y. K.; Chen, W. H.; Cheung, R. T. F.; Divakaramenon, S.; Donnan, G. A.; Duray, G. Z.; Dvorakova, H.; Fiedler, J.; Gardinale, E.; Gates, P. C.; Goshev, E. G.; Goto, S.; Gross, B.; Guimaraes, H. P.; Gulkevych, O.; Haberl, R. L.; Hankey, G.; Hartikainen, J.; Healey, J.; Iliesiu, A. M.; Irkin, O.; Jaxa-Chamiec, T.; Jolly, S.; Kaste, K. A. M.; Kies, B.; Kostov, K. D.; Kristensen, K. S.; Labovitz, A. J.; Lassila, R. P. T.; Lee, K. L. F.; Lutay, Y. M.; Magloire, P.; Mak, K. H.; Meijer, A.; Mihov, L.; Morillo, C. A.; Morillo, L. E.; Nair, G. M.; Norrving, B.; Ntalianis, A.; Ntsekhe, M.; Olah, L.; Pasco, P. M. D.; Peeters, A.; Perovic, V.; Petrov, I.; Pizzolato, G.; Rafti, F.; Rey, N. R.; Ribas, S.; Rokoss, M.; Sarembock, I. J.; Sheth, T.; Shuaib, A.; Sitkei, E.; Sorokin, E.; Srámek, M.; Strozynska, E.; Tanne, D.; Thijs, V. N. S.; Tomek, A.; Turazza, F.; Vanhooren, G.; Vizel, S. A.; Vos, J.; Wahlgren, N.; Weachter, R.; Zaborska, B.; Zaborski, J.; Zimlichman, R.; Cong, J.; Fendt, K.; Muldoon, S.; Bajkor, S.; Grinvalds, A.; Malvaso, M.; Pogue, J.; Simek, K.; Yang, S.; Alzogaray, M. F.; Bono, J. O.; Caccavo, A.; Cartasegna, L.; Casali, W. P.; Cuello, J. L.; Cuneo, C. A.; Elizari, M. V.; Fernandez, A. A.; Ferrari, A. E.; Gabito, A. J.; Goicoechea, R. F.; Gorosito, V. M.; Hirschson, A.; Hominal, M. A.; Hrabar, A. D.; Liberman, A.; Mackinnon, I. J.; Manzano, R. D.; Muratore, C. A.; Nemi, S. A.; Rodriguez, M. A.; Sanchez, A. S.; Secchi, J.; Vogel, D. R.; Colquhoun, D. M.; Crimmins, D. S.; Dart, A. M.; Davis, S. M.; Hand, P. J.; Kubler, P. A.; Lehman, R. G.; McBain, G.; Morrison, H. C.; New, G.; Singh, B. B.; Spence, C. Z.; Waites, J. H.; Auer, J.; Doweik, L.; Freihoff, F.; Gaul, G.; Gazo, F.; Geiger, H.; Giacomini, G.; Huber, G. W.; Jukic, I.; Lamm, G.; Niessner, H.; Podczeck, A.; Schuh, J.; Siostrzonek, P.; Steger, C.; Vogel, B.; Watzak, R.; Weber, H. S.; Weihs, W.; Blankoff, I.; Boland, J. L.; Brike, C.; Carlier, M.; Cools, F.; de Meester, A.; de Raedt, H. J.; de Wolf, L.; Dhooghe, G. M.; Dilling-Boer, D.; Elshot, S. R.; Fasseaux, S.; Goethals, M.; Goethals, P.; Gurne, O.; Hellemans, S.; Ivan, B.; Jottrand, M.; Kersschot, I.; Lecoq, E.; Marcovitch, O.; Melon, D.; Miljoen, H.; Missault, L.; Pierard, L. A.; Provenier, F.; Rousseau, M. F.; Stockman, D.; Tran-Ngoc, E.; van Mieghem, W.; Vandekerckhove, Y.; Vandervoort, P.; Verrostte, J.; Vijgen, J.; Armaganijan, D.; Braga, C.; Braga, J. C. F.; Cipullo, R.; Cunha, C. L. P.; de Paola, A.; Delmonaco, M. I.; Guimaraes, F. V.; Herek, L.; Kerr Saraiva, J. F.; Maia, L. N.; Lorga, A. M.; Lorga-Filho, A. M.; Marino, R. L.; Melo, C. S.; Mouco, O. M.; Pereira, V. C.; Precoma, D. B.; Rabelo, W.; Rassi, S.; Rossi, P. R.; Rossi Neto, J. M.; Silva, F. M.; Vidotti, M. H.; Zimmermann, S. L.; Anev, E. D.; Balabanov, T. A.; Baldjiev, E. S.; Bogusheva, E. S.; Chaneva, M. A.; Filibev, I. G.; Gotcheva, N. N.; Goudev, A. R.; Gruev, I. T.; Guenova, D. T.; Kamenova, Z. A.; Manov, E. I.; Panov, I. A.; Parvanova, Z. I.; Pehlivanova, M. B.; Penchev, P. T.; Penkov, N. Y.; Radoslavov, A. L.; Ramshev, K. N.; Runev, N. M.; Sindzhielieva, M. N.; Spirova, D. A.; Tsanova, V. M.; Tzekova, M. L.; Yaramov, G. K.; Aggarwal, R.; Bakbak, A. I.; Bayly, K.; Berlingieri, J. C.; Blackburn, K.; Bobbie, C.; Booth, A. W.; Borts, D.; Bose, S.; Boucher, P.; Brown, K.; Burstein, J. M.; Butt, J. C.; Carlson, B. D.; Chetty, R.; Chiasson, J. 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L.; Guarnieri, T.; Gupta, A.; Gupta, J.; Hack, T. C.; Hall, B.; Hallak, O.; Halpern, S. W.; Hamburg, C.; Hamroff, G. S.; Han, J.; Handel, F.; Hankins, S. R.; Hanovich, G. D.; Hanrahan, J. A.; Haque, I. U.; Hargrove, J. L.; Harnick, P. E.; Harris, J. L.; Hartley, P. A.; Haskel, E. J.; Hatch, D.; Haught, W. H.; Hearne, S.; Hearne, S. E.; Hemphill, J. A.; Henderson, D. A.; Henes, C. H.; Hengerer-Yates, T.; Hermany, P. R.; Herzog, W. R.; Hickey, K.; Hilton, T. C.; Hockstad, E. S.; Hodnett, P.; Hoffmeister, R.; Holland, J.; Hollenweger, L.; Honan, M. B.; Hoopes, D. A.; Hordes, A. R.; Hotchkiss, D. A.; Howard, M. A.; Howard, V. N.; Hulyalkar, A. R.; Hurst, P.; Hutchison, L. C.; Ingram, J.; Isakov, T.; Ison, R. K.; Israel, C. N.; Jackson, B. K.; Jackson, K. N.; Jacobson, A. K.; Jain, S.; Jarmukli, N. F.; Joffe, I.; Johnson, L. E.; Johnson, S. A.; Johnson, S. L.; Jones, A. A.; Joyce, D. B.; Judson, P. L.; Juk, S. S.; Kaatz, S.; Kaddaha, R. M.; Kaplan, K. J.; Karunaratne, H. B.; Kennett, J. D.; Kenton, D. M.; Kettunen, J. A.; Khan, M. A.; Khant, R. N.; Kirkwood, M. D.; Knight, B. P.; Knight, P. O.; Knutson, T. J.; Kobayashi, J. F.; Kogan, A.; Kogan, A. D.; Koren, M. J.; Kosinski, E. J.; Kosolcharoen, P.; Kostis, J. B.; Kramer, J. H.; Kramer, S. D.; Kron, J.; Kuchenrither, C. R.; Kulback, S. J.; Kumar, A.; Kushner, D.; Kutscher, A.; Lai, C. K.; Lam, J. B.; Landau, C.; Landzberg, J. S.; Lang, D. T.; Lang, J. M.; Lanzarotti, C. J.; Lascewski, D. L.; Lau, T. K.; Lee, J. K.; Lee, S.; Leimbach, W. N.; LePine, A. M.; Lesser, M. F.; Leuchak, S. H.; Levy, R. M.; Lewis, W. R.; Lincoln, T. L.; Lingerfelt, W. M.; Liston, M.; Liu, Z. G.; Lloret, R. L.; Lohrbauer, L.; Longoria, D. C.; Lott, B. M.; Louder, D. R.; Loukinen, K. L.; Lovell, J.; Lue, S.; Mackall, J. A.; Maletz, L.; Marlow, L.; Martin, R. C.; Matsumura, M.; McCartney, M. J.; McDuffie, D.; McGough, M. F.; McGrew, F. A.; McGuinn, Wm P.; McMillen, M. D.; McNeff, J.; McPherson, C. A.; Meengs, M. E.; Meengs, W. L.; Meholick, A. W.; Meisner, J. S.; Melucci, M. B.; Mercando, A.; Merlino, J. D.; Meymandi, S. K.; Miele, M. B.; Miller, R. H.; Miller, S. H.; Minor, S. T.; Mitchell, M. R.; Modi, M.; Mody, F. V.; Moeller, C. L.; Moloney, J. F.; Moran, J. E.; Morcos, N. C.; Morgan, A.; Mukherjee, S. K.; Mullinax, K.; Murphy, A. L.; Mustin, A. J.; Myers, G. I.; Naccarelli, G. V.; Nadar, V. K.; Nallasivan, M.; Navas, J. P.; Niazi, I. K.; Nsah, E. N.; Nunamaker, J. L.; Ochalek, T. B.; O'dea, D. J.; Ogilvie, P. D.; Olliff, B.; Omalley, A. K.; O'Neill, P. G.; Onufer, J. R.; Orchard, R. C.; Orihuela, L. A.; Ortiz, E. C.; O'Sullivan, M. T.; Padanilam, B. J.; Pandey, P.; Patel, D. V.; Patel, R. J.; Patel, V. B.; Patlola, R. R.; Pennock, G. D.; Perlman, R.; Peters, P. H.; Petrillo, A. V.; Pezzella, S.; Phillips, D.; Pierre-Louis, J. R.; Pilcher, G.; Pillai, C.; Pollock, S. G.; Pond, M. S.; Porterfield, J. K.; Presant, L.; Pressler, J.; Pribble, A. H.; Promisloff, S. D.; Pudi, K. K.; Putnam, D. L.; Quartner, J.; Quinn, J. C.; Quinnell, C. M.; Raad, G. L.; Rasmussen, L. A.; Ray, C.; Reiffel, J. A.; Reynertson, S.; Richardson, J. W.; Riley, C. P.; Rippy, J. S.; Rittelmeyer, J. T.; Roberts, D. M.; Robertson, R.; Robinson, V. J. B.; Rocco, T. A.; Rosenbaum, D.; Roth, E. M.; Rottman, J. N.; Rough, R. R.; Rubenstein, J. J.; Sakkal, A. M.; Saleem, T.; Salerno, D. M.; Samendinger, M. L.; Sandeno, S.; Santilli, T. M.; Santucci, P.; Sattar, P.; Saxman, K. A.; Schaefer, S.; Schmidt, J.; Schneider, R. M.; Schocken, D. D.; Schrader, M. K.; Schramm, B. A.; Schultz, R. W.; Schussheim, A. E.; Schwarz, E. F.; Seamon, M. C.; Sestero, J. D.; Shah, M. P.; Shah, R.; Shalaby, A.; Shanes, J. G.; Sheftel, G. L.; Sheikh, K. H.; Shein, A. B.; Shemonsky, N. K.; Shepler, A.; Sheridan, E.; Shipwash, T. M.; Shopnick, R. I.; Short, W. G.; Shoukfeh, M. F.; Sibia, R. S.; Siler, T. M.; Silva, J. A.; Simons, G. R.; Simpson, A. G.; Simpson, H. R.; Simpson, V. J.; Singh, B. N.; Singh, N.; Singh, V. N.; Sitz, C. J.; Skatrud, L.; Sklar, J.; Slotwiner, D. J.; Smith, P. F.; Smith, P. N.; Smith, R. H.; Smith, J. E.; Sodowick, B. C.; Solomon, A. J.; Soltero, E. A.; Sonel, A. F.; Sperling, R.; Spiller, C.; Spink, B. Z.; Sprinkle, L. W.; Spyropoulos, A. C.; Stamos, T. D.; Steljes, A. D.; Stillabower, M. E.; Stover, T.; Strain, J. E.; Strickland, T. L.; Suresh, D. P.; Takata, T. S.; Taylor, J. S.; Taylor, M.; Teague, S. M.; Teixeia, J. M.; Telfer, E. A.; Terry, P. S.; Terry, R. W.; Thai, H. M.; Thalin, M.; Thomas, V. N.; Thompson, C. A.; Thompson, M. A.; Thornton, J. W.; Tidman, R. E.; Toler, B. S.; Traina, M. I.; Trippi, J. A.; Ujiiye, D. L.; Usedom, J. E.; van de Graaff, E.; van de Wall, L. R.; Vaughn, J. W.; Ver Steeg, D.; Vicari, R. M.; Vijay, N.; Vitale, C. B.; Vlastaris, A. G.; Voda, J.; Vora, K. N.; Voyles, W. F.; Vranian, R. B.; Vrooman, P. S.; Waack, P.; Waldo, A. L.; Walker, J. L.; Wallace, M. A.; Walsh, E. A.; Walsh, R. L.; Walton, A.; Washam, M.; Wehner, P. S.; Wei, J. Y.; Weiner, S.; Weiss, R. J.; Wells, D. M.; Wera-Archakul, W.; Wertheimer, J. H.; West, S. A.; Whitaker, J. H.; White, M. L.; White, R. H.; Whitehill, J. N.; Wiegman, P. J.; Wiesel, J.; Williams, J.; Williams, L. E.; Williams, M. L.; Williamson, V. K.; Wilson, V. E.; Wilson, W. W.; Woodfield, S. L.; Wulff, C. W.; Yates, S. W.; Yousuf, K. A.; Zakhary, B. G.; Zambrano, R.; Zimetbaum, P.; Zoble, R.; Zopo, A. R.; Zwerner, P. L.

    2009-01-01

    BACKGROUND: Warfarin reduces the risk of stroke in patients with atrial fibrillation but increases the risk of hemorrhage and is difficult to use. Dabigatran is a new oral direct thrombin inhibitor. METHODS: In this noninferiority trial, we randomly assigned 18,113 patients who had atrial

  18. Comparative study of atrial fibrillation and AV conduction in mammals

    NARCIS (Netherlands)

    Meijler, F.L.; Tweel, I. van der

    1987-01-01

    Atrial fibrillation is one ofthe most common cardiac arrhythmias in humans. It a1so occurs quite frequent1y in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiologica1 mechanisms involved. In this study, we present a quantitative

  19. Quinidine-induced ventricular flutter and fibrillation without digitalis therapy

    NARCIS (Netherlands)

    Koster, R. W.; Wellens, H. J.

    1976-01-01

    Three cases are described with documented ventricular flutter and fibrillation during quinidine medication without concomitant digitalis therapy. In all three patients the arrhythmia developed while they were receiving moderate doses of quinidine. Although no changes in QRS width were observed after

  20. Managing atrial fibrillation in the elderly: critical appraisal of dronedarone

    Directory of Open Access Journals (Sweden)

    Trigo P

    2011-12-01

    Full Text Available Paula Trigo, Gregory W FischerDepartment of Anesthesiology, Mount Sinai School of Medicine, New York, NY, USAAbstract: Atrial fibrillation is the most commonly seen arrhythmia in the geriatric population and is associated with increased cardiovascular morbidity and mortality. Treatment of the elderly with atrial fibrillation remains challenging for physicians, because this unique subpopulation is characterized by multiple comorbidities requiring chronic use of numerous medications, which can potentially lead to severe drug interactions. Furthermore, age-related changes in the cardiovascular system as well as other physiological changes result in altered drug pharmacokinetics. Dronedarone is a new drug recently approved for the treatment of arrhythmias, such as atrial fibrillation and/or atrial flutter. Dronedarone is a benzofuran amiodarone analog which lacks the iodine moiety and contains a methane sulfonyl group that decreases its lipophilicity. These differences in chemical structure are responsible for making dronedarone less toxic than amiodarone which, in turn, results in fewer side effects. Adverse events for dronedarone include gastrointestinal side effects and rash. No dosage adjustments are required for patients with renal impairment. However, the use of dronedarone is contraindicated in the presence of severe hepatic dysfunction.Keywords: atrial fibrillation, elderly, antiarrhythmic agents, amiodarone, dronedarone

  1. Amyloid fibril systems reduce, stabilize and deliver bioavailable nanosized iron

    Science.gov (United States)

    Shen, Yi; Posavec, Lidija; Bolisetty, Sreenath; Hilty, Florentine M.; Nyström, Gustav; Kohlbrecher, Joachim; Hilbe, Monika; Rossi, Antonella; Baumgartner, Jeannine; Zimmermann, Michael B.; Mezzenga, Raffaele

    2017-07-01

    Iron-deficiency anaemia (IDA) is a major global public health problem. A sustainable and cost-effective strategy to reduce IDA is iron fortification of foods, but the most bioavailable fortificants cause adverse organoleptic changes in foods. Iron nanoparticles are a promising solution in food matrices, although their tendency to oxidize and rapidly aggregate in solution severely limits their use in fortification. Amyloid fibrils are protein aggregates initially known for their association with neurodegenerative disorders, but recently described in the context of biological functions in living organisms and emerging as unique biomaterial building blocks. Here, we show an original application for these protein fibrils as efficient carriers for iron fortification. We use biodegradable amyloid fibrils from β-lactoglobulin, an inexpensive milk protein with natural reducing effects, as anti-oxidizing nanocarriers and colloidal stabilizers for iron nanoparticles. The resulting hybrid material forms a stable protein-iron colloidal dispersion that undergoes rapid dissolution and releases iron ions during acidic and enzymatic in vitro digestion. Importantly, this hybrid shows high in vivo iron bioavailability, equivalent to ferrous sulfate in haemoglobin-repletion and stable-isotope studies in rats, but with reduced organoleptic changes in foods. Feeding the rats with these hybrid materials did not result in abnormal iron accumulation in any organs, or changes in whole blood glutathione concentrations, inferring their primary safety. Therefore, these iron-amyloid fibril hybrids emerge as novel, highly effective delivery systems for iron in both solid and liquid matrices.

  2. Antithrombotic therapy in atrial fibrillation associated with valvular heart disease

    DEFF Research Database (Denmark)

    Lip, Gregory Y H; Collet, Jean Philippe; Caterina, Raffaele de

    2017-01-01

    Atrial fibrillation (AF) is a major worldwide public health problem, and AF in association with valvular heart disease (VHD) is also common. However, management strategies for this group of patients have been less informed by randomized trials, which have largely focused on 'non-valvular AF' pati...

  3. Edoxaban versus warfarin in patients with atrial fibrillation

    NARCIS (Netherlands)

    Giugliano, R.P.; Ruff, C.T.; Braunwald, E.; Murphy, S.A.; Wiviott, S.D.; Halperin, J.L.; Waldo, A.L.; Ezekowitz, M.D.; Weitz, J.I.; Spinar, J.; Ruzyllo, W.; Ruda, M.; Koretsune, Y.; Betcher, J.; Shi, M.; Grip, L.T.; Patel, S.P.; Patel, I.; Hanyok, J.J.; Mercuri, M.; Antman, E.M.; Verheugt, F.W.A.; et al.,

    2013-01-01

    BACKGROUND: Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS: We conducted a randomized, double-blind, double-dummy trial comparing two

  4. Edoxaban versus Warfarin in Patients with Atrial Fibrillation

    NARCIS (Netherlands)

    Giugliano, Robert P.; Ruff, Christian T.; Braunwald, Eugene; Murphy, Sabina A.; Wiviott, Stephen D.; Halperin, Jonathan L.; Waldo, Albert L.; Ezekowitz, Michael D.; Weitz, Jeffrey I.; Špinar, Jindřich; Ruzyllo, Witold; Ruda, Mikhail; Koretsune, Yukihiro; Betcher, Joshua; Shi, Minggao; Grip, Laura T.; Patel, Shirali P.; Patel, Indravadan; Hanyok, James J.; Mercuri, Michele; Antman, Elliott M.; Braunwald, E.; Antman, E. M.; Giugliano, R. P.; Ruff, C. T.; Morin, S. E.; Hoffman, E. B.; Murphy, S. A.; Deenadayalu, N.; Grip, L.; Mercuri, M.; Lanz, H.; Patel, I.; Curt, V.; Duggal, A.; Hanyok, J.; Davé, J.; Morgan, D.; Choi, Y.; Shi, M.; Jin, J.; Xie, J.; Crerand, W.; Kappelhof, J.; Maxwell, W.; Zhang, X.; Zhang, Z.; de Groot, J. [=Joris R.; de Vos, R.; Hoekstra, J.

    2013-01-01

    BackgroundEdoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. MethodsWe conducted a randomized, double-blind, double-dummy trial comparing two

  5. Atrial fibrillation in patients with sick sinus syndrome

    DEFF Research Database (Denmark)

    Nielsen, Jens Cosedis; Thomsen, Poul Erik B; Højberg, Søren

    2012-01-01

    between minimal-paced programmed AVI = 100 and >100 ms (median value), respectively (P= 0.60).ConclusionsThe present study indicates that a longer baseline PQ-interval is associated with an increased risk of AF in patients with sick sinus syndrome. Atrial fibrillation burden is not associated...

  6. Management and prognosis of atrial fibrillation in diabetic patients

    DEFF Research Database (Denmark)

    Fumagalli, Stefano; Said, Salah A; Laroche, Cecile

    2017-01-01

    Aims: Diabetes mellitus (DM) is one of the most important cardiovascular (CV) risk factors. The aim of this study was to evaluate clinical correlates of DM, including management and outcomes, in the EURObservational Research Programme (EORP) - Atrial Fibrillation (AF) General Pilot (EORP-AF) Regi...

  7. Surgical Ablation of Atrial Fibrillation Using Energy Sources.

    Science.gov (United States)

    Brick, Alexandre Visconti; Braile, Domingo Marcolino

    2015-01-01

    Surgical ablation, concomitant with other operations, is an option for treatment in patients with chronic atrial fibrillation. The aim of this study is to present a literature review on surgical ablation of atrial fibrillation in patients undergoing cardiac surgery, considering energy sources and return to sinus rhythm. A comprehensive survey was performed in the literature on surgical ablation of atrial fibrillation considering energy sources, sample size, study type, outcome (early and late), and return to sinus rhythm. Analyzing studies with immediate results (n=5), the percentage of return to sinus rhythm ranged from 73% to 96%, while those with long-term results (n=20) (from 12 months on) ranged from 62% to 97.7%. In both of them, there was subsequent clinical improvement of patients who underwent ablation, regardless of the energy source used. Surgical ablation of atrial fibrillation is essential for the treatment of this arrhythmia. With current technology, it may be minimally invasive, making it mandatory to perform a procedure in an attempt to revert to sinus rhythm in patients requiring heart surgery.

  8. Atrial fibrillation: To map or not to map?

    NARCIS (Netherlands)

    A. Yaksh (Ameeta); C. Kik (Charles); S.P. Knops (Simon); J.W. Roos-Hesselink (Jolien); A.J.J.C. Bogers (Ad); F. Zijlstra (Felix); M.A. Allessie (Maurits); N.M.S. de Groot (Natasja)

    2014-01-01

    textabstractIsolation of the pulmonary veins may be an effective treatment modality for eliminating atrial fibrillation (AF) episodes but unfortunately not for all patients. When ablative therapy fails, it is assumed that AF has progressed from a trigger-driven to a substrate-mediated arrhythmia.

  9. Role of the Atrioventricular Node in Atrial Fibrillation

    NARCIS (Netherlands)

    Meijler, F.L.; Wittkampf, F.H.M.

    1997-01-01

    Atrial fibrillation (AF) is probably the most cornmon cardiac arrhythmia in humans, particularly in the elderly (1-3). The irregularity and inequality of the he art beat first described by Hering in 1903 were, and continue to be, the landmark of the clinical diagnosis of AF (4,5). Sir Thomas

  10. A roadmap to improve the quality of atrial fibrillation management

    DEFF Research Database (Denmark)

    Kirchhof, Paulus; Breithardt, Günter; Bax, Jeroen

    2016-01-01

    . Hence, there are important unmet clinical and research needs in the evaluation and management of AF patients. The ensuing needs and opportunities for improving the quality of AF care were discussed during the fifth Atrial Fibrillation Network/European Heart Rhythm Association consensus conference...

  11. Radioiodine therapy in veterinary medicine: treatment of hyperthyroidism in a cat; Die Radioiodtherapie in der Veterinaermedizin: Behandlung der Schilddruesenueberfunktion bei einer Katze

    Energy Technology Data Exchange (ETDEWEB)

    Reinartz, P.; Sabri, O.; Zimny, M.; Buell, U. [Technische Hochschule Aachen (Germany). Klinik fuer Nuklearmedizin; Kinzel, S.; Kuepper, W. [Technische Hochschule Aachen (Germany). Inst. fuer Versuchstierkunde; Bachmann, T. [Tierarztpraxis Dr. med. vet. Thomas Bachmann, Glashhuetten (Germany)

    1999-06-01

    A nine-year-old cat with symptoms of a distinct hyperthyroidism was presented at the University Hospital of the RWTH Aachen. The clinical symptoms as well as the diagnostic procedures performed at the hospital confirmed the diagnosis. After five weeks of thyreostatic medication a regular metabolism of the thyroid gland was established, followed by a radioiodine therapy with 70.3 MBq 131-iodine. Subsequently, the cat was hospitalized for two days before it could be released in good condition. Six weeks after treatment the former drastically reduced weight of the cat recovered to near normal. Even though the chemical analysis detected a discrete hyperthyroidism, clinical symptoms were no longer prominent. Three months after treatment, the final examination showed a regular metabolism of the thyroid gland without a specific thyroidal medication. The presented case illustrates that radioiodine therapy is a safe and efficient treatment of thyroidal dysfunctions in veterinary medicine. (orig.) [Deutsch] Eine neun Jahre alte, europaeische Langhaarkatze wurde mit Symptomen einer ausgepraegten Schilddruesenueberfunktion im Universitaetsklinikum der RWTH Aachen vorgestellt. Sowohl die klinische Symptomatik als auch die Labordiagnostik und die apparativ erhobenen Befunde belegten das Vorliegen einer Hyperthyreose. Im Anschluss an eine fuenfwoechige thyreostatische Therapie, mit der eine euthyreote Stoffwechsellage erreicht werden konnte, wurde eine Radioiodtherapie mit 70,3 MBq 131-Iod durchgefuehrt. Nach einer nur zweitaegigen komplikationslosen Hospitalisierung konnte die Katze in gutem Allgemeinzustand entlassen werden. Sechs Wochen nach der Therapie hatte sich das zuvor deutlich reduzierte Koerpergewicht auf nahezu normgerechte Werte erhoeht; klinische Symptome der Schilddruesenueberfunktion liessen sich trotz einer laborchemisch diagnostizierten diskreten Gesamtthyroxiderhoehung nicht mehr nachweisen. Bei einer abschliessenden Kontrolle drei Monate nach Entlassung wies

  12. Effect of environmental factors on the kinetics of insulin fibril formation: elucidation of the molecular mechanism.

    Science.gov (United States)

    Nielsen, L; Khurana, R; Coats, A; Frokjaer, S; Brange, J; Vyas, S; Uversky, V N; Fink, A L

    2001-05-22

    In the search for the molecular mechanism of insulin fibrillation, the kinetics of insulin fibril formation were studied under different conditions using the fluorescent dye thioflavin T (ThT). The effect of insulin concentration, agitation, pH, ionic strength, anions, seeding, and addition of 1-anilinonaphthalene-8-sulfonic acid (ANS), urea, TMAO, sucrose, and ThT on the kinetics of fibrillation was investigated. The kinetics of the fibrillation process could be described by the lag time for formation of stable nuclei (nucleation) and the apparent rate constant for the growth of fibrils (elongation). The addition of seeds eliminated the lag phase. An increase in insulin concentration resulted in shorter lag times and faster growth of fibrils. Shorter lag times and faster growth of fibrils were seen at acidic pH versus neutral pH, whereas an increase in ionic strength resulted in shorter lag times and slower growth of fibrils. There was no clear correlation between the rate of fibril elongation and ionic strength. Agitation during fibril formation attenuated the effects of insulin concentration and ionic strength on both lag times and fibril growth. The addition of ANS increased the lag time and decreased the apparent growth rate for insulin fibril formation. The ANS-induced inhibition appears to reflect the formation of amorphous aggregates. The denaturant, urea, decreased the lag time, whereas the stabilizers, trimethylamine N-oxide dihydrate (TMAO) and sucrose, increased the lag times. The results indicated that both nucleation and fibril growth were controlled by hydrophobic and electrostatic interactions. A kinetic model, involving the association of monomeric partially folded intermediates, whose concentration is stimulated by the air-water interface, leading to formation of the critical nucleus and thence fibrils, is proposed.

  13. Industrial clusters and economic integration : theoretic concepts and an application to the European Metropolitan Region Nuremberg

    OpenAIRE

    Litzel, Nicole; Möller, Joachim

    2009-01-01

    "Wirtschaftliche Integration geht typischerweise einher mit einer Desintegration des Produktionsprozesses durch Outsourcing und Offshoring (Feenstra 1998). Horizontale und vertikale Verbindungen zwischen Unternehmen werden stärker, so dass die regionalen Wertschöpfungsketten zunehmend als Produktions- oder Innovationscluster organisiert sind. Basierend auf einem Literaturüberblick legen wir dar, dass Cluster im Zuge der wirtschaftlichen Integration eine wichtige Rolle spielen können. Aus dies...

  14. Simulation of pendulum shock experiments on a passenger car front axle; Simulation von Pendelschlagversuchen an einer PKW-Vorderachse

    Energy Technology Data Exchange (ETDEWEB)

    Sporer, L.; Witt, R.; Muehlbauer, R. [BMW Group, Muenchen (Germany)

    2001-07-01

    The contribution describes the development and application of a method for simulating loads resulting from misuse on car body components. The development of the method and its validation by experiments are described, and its application in the development of the BMW-5 series is gone into. [German] Der Beitrag beschreibt die Entwicklung und Anwendung einer Methode zur Simulation von Missbrauchsbelastungen an Fahrwerkskomponenten. Im ersten Abschnitt ist die systematische Entstehung der Methode und die Absicherung der Simulationsergebnisse durch Ersatzversuche dargestellt. In den folgenden Abschnitten steht die Anwendung der Methode in der Fahrwerksentwicklung bei BMW am Beispiel der Vorderachse der aktuellen 5-er Baureihe im Vordergrund. Das Deformationsverhalten einzelner Lenker bzw. die Schadenskette an der gesamten Achse werden sowohl fuer den seitlichen, als auch fuer den frontalen Pendelschlag aufgezeigt. (orig.)

  15. Herausforderungen beim Aufbau und bei der Pflege einer Bilddatenbank – ein Anwendungsbeispiel aus dem Digitalen Forschungsarchiv Byzanz (DiFAB

    Directory of Open Access Journals (Sweden)

    Nina Rannharter

    2017-09-01

    Full Text Available Mit Metadaten versehene, digital archivierte Bilder sind aufgrund ihrer hohen Komplexität eine ständige Herausforderung für den Aufbau von Metadatenstrukturen und für das Beibehalten von adäquaten Metadatenstandards in Bilddatenbanken. Besonders bei Bildern über eine materielle Kultur zeichnet sich diese Komplexität in den diversen Ebenen ab. Zur Verdeutlichung dieser Problematik dient ein einzelnes Monument mit seiner fotographischen Dokumentation als geisteswissenschaftliches Anwendungsbeispiel aus dem Digitalen Forschungsarchiv Byzanz (DiFAB der Universität Wien. Unter der grundsätzlichen Berücksichtigung der künftigen Anforderungen und der einfachen Navigation von Metadaten beinhaltet dieser Beitrag u. a. die Herausforderungen mit den diversen analogen und digitalen Formen der Dokumentation, der historischen Geographie, der kulturspezifischen Terminologie sowie mit der kunsthistorischen Bedeutung einer exakten und unscharfen Datierung für Forschungsarchive.

  16. Gebrauch von Komplementärmedizin bei Patienten mit metastasierendem Melanom unter Therapie mit Ipilimumab innerhalb einer klinischen Studie.

    Science.gov (United States)

    Huebner, Jutta; Mohr, Peter; Simon, Jan-Christoph; Fluck, Michael; Berking, Carola; Zimmer, Lisa; Loquai, Carmen

    2016-05-01

    In Deutschland wenden 40-90 % aller Krebspatienten Methoden der komplementären and alternativen Medizin (KAM) an. Bis dato gibt es kein Datenmaterial zum Einsatz der KAM bei Melanompatienten. Das Ziel unserer Studie war es, Daten über den Gebrauch, die Informationsquellen und Ziele von Patienten mit metastasierendem Melanom zu erfassen. Einhundertsechsundfünfzig Patienten aus 25 Studienzentren nahmen an der DecOG-MM-PAL Multibasket Studie teil. Die beteiligten Personen wurden auch gebeten, an einer Nebenstudie teilzunehmen, die ihren Gebrauch von KAM erfassen sollte. Dazu wurde während der Behandlung ein standardisierter Fragebogen zu genau festgelegten Zeitpunkten ausgeteilt. Insgesamt gingen 55 Fragebögen von 32 (21 %) Melanompatienten ein. Von diesen gaben 17 (53 %) ein Interesse an KAM an, und sieben (22 %) machten von KAM Gebrauch. Die Hauptinformationsquellen (31 %) waren Familienmitglieder und Freunde, gefolgt von Ärzten (19 %). Die Hauptgründe für die Anwendung von KAM waren die Stärkung des Immunsystems (41 %) und des Körpers (34 %). Nahrungsergänzungsmittel (Vitamine und Spurenelemente) wurden am häufigsten angewendet (28 %). Eine relativ hohe Anzahl an Patienten mit metastasierendem Melanom machte trotz Teilnahme an einer klinischen Studie von KAM Gebrauch. Wechselwirkungen könnten durch biologisch basierte KAM auftreten, und hier besonders bei immunmodulierenden KAM- Strategien. Um Risiken zu vermeiden, sollte die Kommunikation zwischen den Ärzten und den Patienten verbessert werden. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  17. Development and application of a new tool in driver task analysis; Entwicklung und Anwendung einer neuen Methodik zur Fahreraufgabenanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Fastenmeier, W.; Gstalter, H. [mensch-verkehr-umwelt Institut fuer Angewandte Psychologie, Muenchen (Germany)

    2003-07-01

    A framework for driver task analysis is derived from a model of the drivers information processing. The first step of the procedure (SAFE) is to divide a given driving task (e.g. left turning in a signalised intersection of a certain type) into subtasks. These subtasks are appointed to defined stretches of the road and the time structure of the subtasks is determined. For each subtask an analysis format is used, that organizes different requirements into perception, expectation, judgement, memory, decision and driver action. In a next step, typical driver errors are appointed to the subtasks. Afterwards the information gathered in the analysis procedure is compressed to ratings of the complexity and risk included in each subtask. After the crucial subtasks of a driving task have been determined, a list of those requirements that led to that rating can be compiled. These lists give the potential for aiding the driver e.g. by use of driver assistance systems. (orig.) [German] In den Verkehrswissenschaften existieren bislang keine verkehrsspezifischen Standardverfahren, die eine Anforderungsanalyse auf der Ebene der Fahraufgaben erlauben. Dieser Beitrag stellt die Grundzuege eines Verfahrens zur Fahraufgabenanalyse dar (SAFE: Situative Anforderungsanalyse von Fahraufgaben). Es basiert auf einer Modellvorstellung zu den Informationsverarbeitungsprozessen, die waehrend der Bewaeltigung der Fahraufgabe eine Rolle spielen. Der erste Schritt der Aufgabenanalyse besteht darin, eine ausgewaehlte Fahraufgabe (z.B. Linksabbiegen in einer ampelgeregelten Kreuzung bestimmten Typs) in Teilaufgaben zu zerlegen und eine zeitliche Strukturierung dieser Teilaufgaben vorzunehmen. Diese werden raeumlichen Segmenten zugeordnet, die nacheinander durchfahren werden muessen. Fuer jede Teilaufgabe erfolgt dann die eigentliche Anforderungsanalyse, die nach den Kapiteln Wahrnehmung, Erwartungsbildung, Beurteilung, Gedaechtnisprozesse, Entscheidung/Planung sowie Fahrzeugbedienung mit jeweils

  18. Albumin fibrillization induces apoptosis via integrin/FAK/Akt pathway

    Directory of Open Access Journals (Sweden)

    Liang Chi-Ming

    2009-01-01

    Full Text Available Abstract Background Numerous proteins can be converted to amyloid-like fibrils to increase cytotoxicity and induce apoptosis, but the methods generally require a high concentration of protein, vigorous shaking, or fibril seed. As well, the detailed mechanism of the cytotoxic effects is not well characterized. In this study, we have developed a novel process to convert native proteins into the fibrillar form. We used globular bovine serum albumin (BSA as a model protein to verify the properties of the fibrillar protein, investigated its cellular effects and studied the signaling cascade induced by the fibrillar protein. Results We induced BSA, a non-cytotoxic globular protein, to become fibril by a novel process involving Superdex-200 column chromatography in the presence of anionic or zwittergenic detergent(s. The column pore size was more important than column matrix composite in fibril formation. The fibrillar BSA induced apoptosis in BHK-21 cell as well as breast cancer cell line T47D. Pre-treating cells with anti-integrin antibodies blocked the apoptotic effect. Fibrillar BSA, but not globular BSA, bound to integrin, dephosphorylated focal adhesion kinase (FAK, Akt and glycogen synthase kinase-3β (GSK-3β. Conclusion We report on a novel process for converting globular proteins into fibrillar form to cause apoptosis by modulating the integrin/FAK/Akt/GSK-3β/caspase-3 signaling pathway. Our findings may be useful for understanding the pathogenesis of amyloid-like fibrils and applicable for the development of better therapeutic agents that target the underlying mechanism(s of the etiologic agents.

  19. Fibril specific, conformation dependent antibodies recognize a generic epitope common to amyloid fibrils and fibrillar oligomers that is absent in prefibrillar oligomers

    Directory of Open Access Journals (Sweden)

    Rasool Suhail

    2007-09-01

    Full Text Available Abstract Background Amyloid-related degenerative diseases are associated with the accumulation of misfolded proteins as amyloid fibrils in tissue. In Alzheimer disease (AD, amyloid accumulates in several distinct types of insoluble plaque deposits, intracellular Aβ and as soluble oligomers and the relationships between these deposits and their pathological significance remains unclear. Conformation dependent antibodies have been reported that specifically recognize distinct assembly states of amyloids, including prefibrillar oligomers and fibrils. Results We immunized rabbits with a morphologically homogeneous population of Aβ42 fibrils. The resulting immune serum (OC specifically recognizes fibrils, but not random coil monomer or prefibrillar oligomers, indicating fibrils display a distinct conformation dependent epitope that is absent in prefibrillar oligomers. The fibril epitope is also displayed by fibrils of other types of amyloids, indicating that the epitope is a generic feature of the polypeptide backbone. The fibril specific antibody also recognizes 100,000 × G soluble fibrillar oligomers ranging in size from dimer to greater than 250 kDa on western blots. The fibrillar oligomers recognized by OC are immunologically distinct from prefibrillar oligomers recognized by A11, even though their sizes overlap broadly, indicating that size is not a reliable indicator of oligomer conformation. The immune response to prefibrillar oligomers and fibrils is not sequence specific and antisera of the same specificity are produced in response to immunization with islet amyloid polypeptide prefibrillar oligomer mimics and fibrils. The fibril specific antibodies stain all types of amyloid deposits in human AD brain. Diffuse amyloid deposits stain intensely with anti-fibril antibody although they are thioflavin S negative, suggesting that they are indeed fibrillar in conformation. OC also stains islet amyloid deposits in transgenic mouse models of type

  20. Familial clustering of atrial fibrillation and comparative longitudinal outcomes of familial and non-familial atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Olesen, Jonas B.; Peterson, Eric D.

    2017-01-01

    Several studies have suggested that family history of atrial fibrillation (AF) is an important risk factor for AF, with several specific genetic regions now implicated through Genome Wide Association Studies. In addition, familial AF is associated with earlier age of onset and affects patients...

  1. Early recurrences of atrial fibrillation after electrical cardioversion : A result of fibrillation-induced electrical remodeling of the atria?

    NARCIS (Netherlands)

    Tieleman, RG; Van Gelder, IC; Crijns, HJGM; De Kam, PJ; Van den Berg, MP; Haaksma, J; Van der Woude, HJ; Allessie, MA

    Objectives, We sought to investigate whether, in humans, the timing and incidence of a relapse of atrial fibrillation (AF) during the first month after cardioversion indicates the presence of electrical remodeling and whether this could be influenced by prevention of intracellular calcium overload

  2. Combined role of type IX collagen and cartilage oligomeric matrix protein in cartilage matrix assembly: Cartilage oligomeric matrix protein counteracts type IX collagen-induced limitation of cartilage collagen fibril growth in mouse chondrocyte cultures

    NARCIS (Netherlands)

    Blumbach, K.; Bastiaansen-Jenniskens, Y.M.; Groot, J. de; Paulsson, M.; Osch, G.J.V.M. van; Zaucke, F.

    2009-01-01

    Objective. Defects in the assembly and composition of cartilage extracellular matrix are likely to result in impaired matrix integrity and increased susceptibility to cartilage degeneration. The aim of this study was to determine the functional interaction of the collagen fibril-associated proteins

  3. Collateral findings during computed tomography scan for atrial fibrillation ablation: Let's take a look around.

    Science.gov (United States)

    Perna, Francesco; Casella, Michela; Narducci, Maria Lucia; Dello Russo, Antonio; Bencardino, Gianluigi; Pontone, Gianluca; Pelargonio, Gemma; Andreini, Daniele; Vitulano, Nicola; Pizzamiglio, Francesca; Conte, Edoardo; Crea, Filippo; Tondo, Claudio

    2016-04-26

    The growing number of atrial fibrillation catheter ablation procedures warranted the development of advanced cardiac mapping techniques, such as image integration between electroanatomical map and cardiac computed tomography. While scanning the chest before catheter ablation, it is frequent to detect cardiac and extracardiac collateral findings. Most collateral findings are promptly recognized as benign and do not require further attention. However, sometimes clinically relevant collateral findings are detected, which often warrant extra diagnostic examinations or even invasive procedure, and sometimes need to be followed-up over time. Even though reporting and further investigating collateral findings has not shown a clear survival benefit, almost all the working groups providing data on collateral findings reported some collateral findings eventually coming out to be malignancies, sometimes at an early stage. Therefore, there is currently no clear agreement about the right strategy to be followed.

  4. Spiral CT in aplasia of the pre-renal inferior vena cava as a cause of phlebothrombosis from the femoral veins to the inferior vena cava; Spiral-CT einer Aplasie der praerenalen Vena cava inferior als Ursache einer Phlebothrombose von den Oberschenkelvenen bis in die Vena cava inferior

    Energy Technology Data Exchange (ETDEWEB)

    Schweiger, U. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany); Schedel, H. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany); Thiede, U. [Deutsches Herzzentrum Berlin (Germany). Arbeitsgruppe Digitale Bildbearbeitung; Felix, R. [Strahlenklinik und Poliklinik, Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin (Germany)

    1994-12-31

    The case report focuses on the computed tomography of the thrombotic okklusion of the inferior vena cava, venae iliacae and femorales communes due to congenital interruption of the prerenal inferior vena cava. The embryology of the abnormality was discussed. (orig.) [Deutsch] Anhand einer Fallstudie wurden die Moeglichkeiten der computertomographischen Diagnostik bei einer durch Teilplasie der `praerenalen` Vena cava inferior hervorgerufenen Thrombose der Vv. femorales superficiales et profundae, der grossen Beckenvenen und der Vena cava inferior erlaeutert. In der Diskussion wurde auf die Embryologie der Missbildung eingegangen. (orig.)

  5. Structural and functional characteristics of myocard in patients with different forms of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    L. I. Vasilyeva

    2015-02-01

    Full Text Available Aim. To study structural and functional characteristics of myocard in patients with different forms of atrial fibrillation. Atrial fibrillation is the most prevalent arrhythmia in clinical practice. Atrial fibrillation is a progressive disease: the duration of paroxysms increases over time and paroxysmal atrial fibrillation transforms to persistent, the last one becomes refractory to pharmacological and electrical cardioversion in time and transforms to permanent. So assessment of myocardial remodeling in patients with persistent and permanent atrial fibrillation is very actual. Methods and results. According to the aim of the study 133 patients with persistent atrial fibrillation and 100 patients with permanent atrial fibrillation were included into the study. Echocardiographic parameters of left and right atria function were studied. Conclusion. It was found that patients with persistent and permanent atrial fibrillation are characterized with both left and right atrias remodeling. Remodeling of the atrias is less pronounced in patients with permanent atrial fibrillation in comparison with persistent atrial fibrillation patients and arrhythmia recurrence.

  6. Structural evaluation of an amyloid fibril model using small-angle x-ray scattering

    Science.gov (United States)

    Dahal, Eshan; Choi, Mina; Alam, Nadia; Bhirde, Ashwinkumar A.; Beaucage, Serge L.; Badano, Aldo

    2017-08-01

    Amyloid fibrils are highly structured protein aggregates associated with a wide range of diseases including Alzheimer’s and Parkinson’s. We report a structural investigation of an amyloid fibril model prepared from a commonly used plasma protein (bovine serum albumin (BSA)) using small-angle x-ray scattering (SAXS) technique. As a reference, the size estimates from SAXS are compared to dynamic light scattering (DLS) data and the presence of amyloid-like fibrils is confirmed using Congo red absorbance assay. Our SAXS results consistently show the structural transformation of BSA from spheroid to rod-like elongated structures during the fibril formation process. We observe the elongation of fibrils over two months with fibril length growing from 35.9  ±  3.0 nm to 51.5  ±  2.1 nm. Structurally metastable fibrils with distinct SAXS profiles have been identified. As proof of concept, we demonstrate the use of such distinct SAXS profiles to detect fibrils in the mixture solutions of two species by estimating their volume fractions. This easily detectable and well-characterized amyloid fibril model from BSA can be readily used as a control or standard reference to further investigate SAXS applications in the detection of structurally diverse amyloid fibrils associated with protein aggregation diseases.

  7. Phosphate and HEPES buffers potently affect the fibrillation and oligomerization mechanism of Alzheimer's Aβ peptide

    International Nuclear Information System (INIS)

    Garvey, Megan; Tepper, Katharina; Haupt, Caroline; Knuepfer, Uwe; Klement, Karolin; Meinhardt, Jessica; Horn, Uwe; Balbach, Jochen; Faendrich, Marcus

    2011-01-01

    Highlights: → Sodium phosphate buffer accelerated Aβ(1-40) nucleation relative to HEPES. → Aβ(1-40) fibrils formed in the two buffers show only minor structural differences. → NMR revealed that Aβ(1-40) histidine residues mediate buffer dependent changes. -- Abstract: The oligomerization of Aβ peptide into amyloid fibrils is a hallmark of Alzheimer's disease. Due to its biological relevance, phosphate is the most commonly used buffer system for studying the formation of Aβ and other amyloid fibrils. Investigation into the characteristics and formation of amyloid fibrils frequently relies upon material formed in vitro, predominantly in phosphate buffers. Herein, we examine the effects on the fibrillation and oligomerization mechanism of Aβ peptide that occur due solely to the influence of phosphate buffer. We reveal that significant differences in amyloid fibrillation are observed due to fibrillation being initiated in phosphate or HEPES buffer (at physiological pH and temperature). Except for the differing buffer ions, all experimental parameters were kept constant. Fibril formation was assessed using fluorescently monitored kinetic studies, microscopy, X-ray fiber diffraction and infrared and nuclear magnetic resonance spectroscopies. Based on this set up, we herein reveal profound effects on the mechanism and speed of Aβ fibrillation. The three histidine residues at positions 6, 13 and 14 of Aβ(1-40) are instrumental in these mechanistic changes. We conclude that buffer plays a more significant role in fibril formation than has been generally acknowledged.

  8. Contact force sensing for ablation of persistent atrial fibrillation: A randomized, multicenter trial.

    Science.gov (United States)

    Conti, Sergio; Weerasooriya, Rukshen; Novak, Paul; Champagne, Jean; Lim, Hong Euy; Macle, Laurent; Khaykin, Yaariv; Pantano, Alfredo; Verma, Atul

    2018-02-01

    Impact of contact force sensing (CFS) on ablation of persistent atrial fibrillation (PeAF) is unknown. The purpose of the TOUCH AF (Therapeutic Outcomes Using Contact force Handling during Ablation of Persistent Atrial Fibrillation) randomized trial was to compare CFS-guided ablation to a CFS-blinded strategy. Patients (n = 128) undergoing first-time ablation for persistent AF were randomized to a CFS-guided vs CFS-blinded strategy. In the CFS-guided procedure, operators visualized real-time force data. In the blinded procedure, force data were hidden. Wide antral pulmonary vein isolation plus a roof line were performed. Patients were followed at 3, 6, 9, and 12 months with clinical visit, ECG, and 48-hour Holter monitoring. The primary endpoint was cumulative radiofrequency (RF) time for all procedures. Atrial arrhythmia >30 seconds after 3 months was a recurrence. PeAF was continuous for 26 weeks (interquartile range [IQR] 13-52), and left atrial size was 45 ± 5 mm. Force in the CFS-blinded and CFS-guided arms was 12 g [IQR 6-20] and 14 g [IQR 9-20] (P = .10), respectively. Total RF time did not differ between CFS-guided and CFS-blinded groups (49 ± 14 min vs 50 ± 20 min, respectively; P = .70). Single procedure freedom from atrial arrhythmia was 60% in the CFS-guided arm and 63% in the CFS-blinded arm off drugs. Lesions with gaps were associated with significantly less force (11.4 g [IQR 6-19] vs 13.2 g [IQR 8-20], respectively; P = .0007) and less force-time integral (174 gs [IQR 91-330] vs 210 gs [IQR 113-388], respectively; P force/force-time integral was associated with significantly more gaps. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  9. Changes in plasma atrial natriuretic factor in patients with idiopathic atrial fibrillation

    International Nuclear Information System (INIS)

    Du Tongxin; Xia Xiaojie; Qu Wei; Wang Shukui; Sun Junjiang

    2002-01-01

    To observe the changes in plasma atrial natriuretic factor (AFN) in patients with idiopathic atrial fibrillation and investigate its mechanism, plasma ANF, platelet count and hematocrit were detected in 21 cases with transient idiopathic atrial fibrillation (group A, A1 representing attack, while A2 termination), 28 with persistent idiopathic atrial fibrillation (group B), 27 suffered from rheumatic heart disease with mitral stenosis and persistent atrial fibrillation (group C), 32 with transient supraventricular tachycardia (group D) and 20 normal controls (group E). It was found that the level of ANF was significantly higher in patients with attacking transient idiopathic atrial fibrillation than that in group A2, D and E (P 0.05), while there was significant difference in hematocrit in group A1 compared with group A2, D, E (P < 0.01). It suggested that ANF and hematocrit play an important role in the attack of idiopathic atrial fibrillation

  10. Synergistic Inhibition of Protein Fibrillation by Proline and Sorbitol: Biophysical Investigations.

    Directory of Open Access Journals (Sweden)

    Sinjan Choudhary

    Full Text Available We report here interesting synergistic effects of proline and sorbitol, two well-known chemical chaperones, in the inhibition of fibrillation of two proteins, insulin and lysozyme. A combination of many biophysical techniques has been used to understand the structural morphology and modes of interaction of the chaperones with the proteins during fibrillation. Both the chaperones establish stronger polar interactions in the elongation and saturation stages of fibrillation compared to that in the native stage. However, when presented as a mixture, we also see contribution of hydrophobic interactions. Thus, a co-operative adjustment of polar and hydrophobic interactions between the chaperones and the protein surface seems to drive the synergistic effects in the fibrillation process. In insulin, this synergy is quantitatively similar in all the stages of the fibrillation process. These observations would have significant implications for understanding protein folding concepts, in general, and for designing combination therapies against protein fibrillation, in particular.

  11. Synergistic Inhibition of Protein Fibrillation by Proline and Sorbitol: Biophysical Investigations.

    Science.gov (United States)

    Choudhary, Sinjan; Save, Shreyada N; Kishore, Nand; Hosur, Ramakrishna V

    2016-01-01

    We report here interesting synergistic effects of proline and sorbitol, two well-known chemical chaperones, in the inhibition of fibrillation of two proteins, insulin and lysozyme. A combination of many biophysical techniques has been used to understand the structural morphology and modes of interaction of the chaperones with the proteins during fibrillation. Both the chaperones establish stronger polar interactions in the elongation and saturation stages of fibrillation compared to that in the native stage. However, when presented as a mixture, we also see contribution of hydrophobic interactions. Thus, a co-operative adjustment of polar and hydrophobic interactions between the chaperones and the protein surface seems to drive the synergistic effects in the fibrillation process. In insulin, this synergy is quantitatively similar in all the stages of the fibrillation process. These observations would have significant implications for understanding protein folding concepts, in general, and for designing combination therapies against protein fibrillation, in particular.

  12. Does in-hospital ventricular fibrillation affect prognosis after myocardial infarction?

    DEFF Research Database (Denmark)

    Jensen, G V; Torp-Pedersen, C; Hildebrandt, P

    1997-01-01

    with ventricular fibrillation in time intervals, indicated that the importance of ventricular fibrillation for risk of death was exhausted during the initial 60 days after infarction. CONCLUSION: Ventricular fibrillation is associated with an independent increased risk of death within 0-60 days after infarction......AIM: The aim of this study was to estimate the prognostic information to be gained from ventricular fibrillation in patients with myocardial infarction. METHODS AND RESULTS: We studied 4259 consecutive patients with myocardial infarction admitted to one centre in 1977-1988. Five hundred and twenty......-eight (12.4%) of the patients had ventricular fibrillation in hospital. The following risk factors were included in multivariate models to estimate their importance for 30-day and long-term (median 7 year) prognosis: age, gender, ventricular fibrillation, congestive heart failure, pulmonary oedema...

  13. Decision-making interventions to stop the global atrial fibrillation-related stroke tsunami.

    Science.gov (United States)

    Cerasuolo, Joshua O; Montero-Odasso, Manuel; Ibañez, Agustin; Doocy, Shannon; Lip, Gregory Yh; Sposato, Luciano A

    2017-04-01

    Atrial fibrillation affects 33.5 million people worldwide and its prevalence is expected to double by 2050 because of the aging population. Atrial fibrillation confers a 5-fold higher risk of ischemic stroke compared to sinus rhythm. We present our view of the role of shared medical decision-making to combat global underutilization of oral anticoagulation for stroke prevention in atrial fibrillation patients. Oral anticoagulation underuse is widespread as it is present within atrial fibrillation patients of all risk strata and in countries across all income levels. Reasons for oral anticoagulation underuse include but are probably not limited to poor risk stratification, over-interpretation of contraindications, and discordance between physician prescription preferences and actual administration. By comparing a catastrophic event to the consequences of atrial fibrillation related strokes, it may help physicians and patients understand the negative outcomes associated with oral anticoagulation under-utilization and the magnitude to which oral anticoagulations neutralize atrial fibrillation burden.

  14. Novel squarylium dyes for detection of amyloid fibrils in vitro

    Directory of Open Access Journals (Sweden)

    K. O. Vus

    2015-04-01

    Full Text Available A series of novel symmetrical and asymmetrical squarylium dyes with the different substituents in the donor moieties have been tested for their ability to detect and characterize insulin and lysozyme amyloid fibrils prepared in acidic buffer at elevated temperature. The dye-protein binding parameters were estimated in terms of the one-site Langmuir adsorption model using the data of direct and reverse fluorimetric titrations. By comparing the dye quantum yields, binding affinities, and extents of the fluorescence enhancement in the protein-bound state, G6 and G7 were selected as the most prospective amyloid tracers. Furthermore, these probes provided evidence for the lower polarity of the lysozyme fibrillar grooves compared to insulin aggregates. The novel dyes G6 and G7 were recommended for amyloid fibril detection and characterization in the near-infrared region.

  15. Dynamical mechanism of atrial fibrillation: A topological approach

    Science.gov (United States)

    Marcotte, Christopher D.; Grigoriev, Roman O.

    2017-09-01

    While spiral wave breakup has been implicated in the emergence of atrial fibrillation, its role in maintaining this complex type of cardiac arrhythmia is less clear. We used the Karma model of cardiac excitation to investigate the dynamical mechanisms that sustain atrial fibrillation once it has been established. The results of our numerical study show that spatiotemporally chaotic dynamics in this regime can be described as a dynamical equilibrium between topologically distinct types of transitions that increase or decrease the number of wavelets, in general agreement with the multiple wavelets' hypothesis. Surprisingly, we found that the process of continuous excitation waves breaking up into discontinuous pieces plays no role whatsoever in maintaining spatiotemporal complexity. Instead, this complexity is maintained as a dynamical balance between wave coalescence—a unique, previously unidentified, topological process that increases the number of wavelets—and wave collapse—a different topological process that decreases their number.

  16. Unexpected guest: Atrial fibrillation due to electrical shock

    Directory of Open Access Journals (Sweden)

    Mehmet Zihni Bilik

    2016-03-01

    Full Text Available Cardiac arrhythmias due to electrical injuries are rare among emergency service admittances. A 35 year-old female patient was admitted to emergency service with palpitation after electrical injury as a result of contact with a domestic low-voltage source. Electrocardiography (ECG showed atrial fibrillation with rapid ventricular response. Transthoracic echocardiography findings were normal. Atrial fibrillation spontaneously converted to normal sinus rhythm after rate limiting treatment with beta-blocker. The patient was discharged without any complication on the third day of hospitalization. Although cardiac arrhythmias rarely occur after electrical injury, cardiac monitoring is recommended for all patients with documented rhythm disorder, loss of consciousness, or abnormal ECG at admission.

  17. Atrial fibrillation in fracture patients treated with oral bisphosphonates

    DEFF Research Database (Denmark)

    Abrahamsen, B; Eiken, P; Brixen, K

    2009-01-01

    OBJECTIVES: To determine if patients receiving oral bisphosphonates are at excess risk of atrial fibrillation (AF), stroke and myocardial infarction. DESIGN: Register-based restricted cohort study. SETTING: National Hospital Discharge Register and National Prescriptions Database (1995-2005). SUBJ......OBJECTIVES: To determine if patients receiving oral bisphosphonates are at excess risk of atrial fibrillation (AF), stroke and myocardial infarction. DESIGN: Register-based restricted cohort study. SETTING: National Hospital Discharge Register and National Prescriptions Database (1995...... to adherence. There was no increased risk of ischaemic stroke and an increased risk of myocardial infarction was not significant after adjustment for comorbidity. CONCLUSIONS: The increased occurrence of AF in fracture patients who are users of oral bisphosphonates should be attributed to targeting...

  18. Paroxysmal atrial fibrillation occurs often in cryptogenic ischaemic stroke

    DEFF Research Database (Denmark)

    Christensen, L M; Krieger, D W; Højberg, S

    2014-01-01

    BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial fibrilla......BACKGROUND AND PURPOSE: Atrial fibrillation (AF) increases the risk of stroke fourfold and is associated with a poor clinical outcome. Despite work-up in compliance with guidelines, up to one-third of patients have cryptogenic stroke (CS). The prevalence of asymptomatic paroxysmal atrial...... lasting predominantly between 1 and 4 h. Four recurrent strokes were observed, three in patients with PAF; all three patients were on oral anticoagulation (OAC). CONCLUSIONS: One in five patients with CS had PAF, which occurred at low burden and long after stroke. Future studies should determine the role...

  19. [Atrial fibrillation as consequence and cause of structural changes of atria].

    Science.gov (United States)

    Aparina, O P; Chikhireva, L N; Stukalova, O V; Mironova, N A; Kashtanova, S Iu; Ternovoĭ, S K; Golitsyn, S P

    2014-01-01

    Changes of atrial structure and function are the contributors of atrial fibrillation clinical course, complications and treatment effectiveness. Effects of inflammation and mechanical stretch on atrial structural remodeling leading to atrial fibrillation are reviewed in the article. Contemporary invasive and non-invasive methods of evaluation (including late gadolinium enhancement magnetic resonance imaging) of patients with atrial structural remodeling in atrial fibrillation are also described.

  20. Is Supramolecular Filament Chirality the Underlying Cause of Major Morphology Differences in Amyloid Fibrils?

    Science.gov (United States)

    2015-01-01

    The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for “normal” left-hand-helical filaments and below pH 2 for “reversed” right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218–289) prion, and a short polypeptide fragment of transthyretin, TTR (105–115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases. PMID:24484302

  1. Is supramolecular filament chirality the underlying cause of major morphology differences in amyloid fibrils?

    Science.gov (United States)

    Kurouski, Dmitry; Lu, Xuefang; Popova, Ludmila; Wan, William; Shanmugasundaram, Maruda; Stubbs, Gerald; Dukor, Rina K; Lednev, Igor K; Nafie, Laurence A

    2014-02-12

    The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for "normal" left-hand-helical filaments and below pH 2 for "reversed" right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218-289) prion, and a short polypeptide fragment of transthyretin, TTR (105-115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases.

  2. Cardiac ion channels and mechanisms for protection against atrial fibrillation

    DEFF Research Database (Denmark)

    Grunnet, Morten; Bentzen, Bo Hjorth; Sørensen, Ulrik S

    2011-01-01

    Atrial fibrillation (AF) is recognised as the most common sustained cardiac arrhythmia in clinical practice. Ongoing drug development is aiming at obtaining atrial specific effects in order to prevent pro-arrhythmic, devastating ventricular effects. In principle, this is possible due to a differe...... to the recent discovery that Ca(2+)-activated small conductance K(+) channels (SK channels) are important for the repolarisation of atrial action potentials. Finally, an overview of current pharmacological treatment of AF is included....

  3. Slow ventricular response atrial fibrillation related to mad honey poisoning

    Science.gov (United States)

    Osken, A.; Yaylacı, S.; Aydın, E.; Kocayigit, İ; Cakar, M.A.; Tamer, A.; Gündüz, H.

    2012-01-01

    Mad honey poisoning which is induced by Grayanotoxin (Andromedotoxin), is also known to have adverse effects in the cardiovascular system leading to different clinical entities. This toxin is produced by a member of the Rhododendron genus of plants of two R. Luteum and R. Panticum. In this article, we presented a case of slow ventricular response atrial fibrillation complaints with nausea, vomiting, dizziness and chest pain about an hour after eating honey produced in the Black Sea Region. PMID:22923947

  4. Slow ventricular response atrial fibrillation related to mad honey poisoning

    OpenAIRE

    Osken, A.; Yaylacı, S.; Aydın, E.; Kocayigit, İ; Cakar, M.A.; Tamer, A.; Gündüz, H.

    2012-01-01

    Mad honey poisoning which is induced by Grayanotoxin (Andromedotoxin), is also known to have adverse effects in the cardiovascular system leading to different clinical entities. This toxin is produced by a member of the Rhododendron genus of plants of two R. Luteum and R. Panticum. In this article, we presented a case of slow ventricular response atrial fibrillation complaints with nausea, vomiting, dizziness and chest pain about an hour after eating honey produced in the Black Sea Region.

  5. Precision of MR-guided needle placement. Experimental results; Praezision der Lokalisierbarkeit einer Punktionsnadel in der MRT. Experimentelle Ergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Langen, H.J. [Roentgenabteilung der Missionsaerztlichen Klinik Wuerzburg (Germany); Stuetzer, H. [Inst. fuer Medizinische Statistik, Informatik und Epidemiologie der Univ. zu Koeln (Germany); Kugel, H.; Krug, B.; Hesselmann, V.; Schulte, O.; Walter, C.; Landwehr, P. [Inst. und Poliklinik fuer Radiologische Diagnostik der Univ. zu Koeln (Germany)

    2000-11-01

    To estimate the accuracy of the determination of tip position of MR compatible biopsy needles based on signal voids and artifacts in MR guided biopsies. Method: In a nylon grid phantom an MR compatible 18G needle (E-Z-EM) was measured in a 1.0 T imager using TSE- and FFE-sequences of 20 s and 40 s duration in 34 different orientations of needle versus B{sub 0}, frequency and slice selection gradient. 4 radiologists with no experience in the evaluation of signal void artifacts estimated the needle tip positions from needle tip artifacts. The readers determined the needle tip before and after a 15 minute training session based on high resolution images with explanation of size and shape of specific artifacts of biopsy needles in 12 different orthogonal or parallel orientations to B{sub 0} and frequency encoding gradient that are possible if the needle lies parallel to the slice, i.e. orthogonal to the slice selection gradient. The values obtained before and after the training session were compared to the real position of the needle tip. Results: Mean distance of actual needle tip and tip position as determined from images was 1.8{+-}2.3 mm in TSE- versus 2.5{+-}1.2 mm in FFE-images, with the needle length overestimated. After a 15 minute training session the positioning error decreased significantly to 0.2{+-}1.8 mm for TSE-sequences and to 1.0{+-}1.8 mm for FFE-sequences. A higher accuracy of tip localization was obtained with TSE sequences. Conclusion: In MR guided biopsies using FFE- and TSE-sequences the needle position can be more accurately determined if the reader is familiar with the 12 orthogonal or parallel positions of the needle with respect to B{sub 0} and frequency encoding gradient and the corresponding artifacts. (orig.) [German] Abschaetzung der Praezision, mit der die Spitze einer MR-kompatiblen Biopsienadel anhand ihrer Artefakte bestimmt werden kann. Methode: Experimentell wurde eine MR-kompatible 18 G Biopsienadel (E-Z-EM) in einem 1,0 Tesla MR

  6. Basic methodology of tomographic imaging by filtered inverse projection at a turbo-pump. Project report; Methodische Grundlagen fuer die Tomographie durch gefilterte Rueckprojektion an einer Axialpumpe. Projektbericht

    Energy Technology Data Exchange (ETDEWEB)

    Hoppe, D.

    2000-11-01

    A two-phase medium consisting of a fluid containing gas is transported in a turbo-pump via an impeller. The interaction between the gaseous phase and the impeller is to be examined by tomography with gamma rays. Reconstruction of the image of the object is to be made by way of filtered inverse projection. The methodology of using this principle in the given system (geometry and measuring conditions) is explained. (orig./CB) [German] Ein zweiphasiges, aus einer gashaltigen Fluessigkeit bestehendes Medium wird in einer Axialpumpe von einem propellerartigen Laufrad senkrecht zur Drehachse dieses Laufrades transportiert. Die Wechselwirkung zwischen der Gasphase und dem Laufrad soll unter Verwendung von Gamma-Strahlung mittels Tomographie untersucht werden. Dabei ist fuer die Rekonstruktion des Objektbildes das Prinzip der sogenannten gefilterten Rueckprojektion vorgesehen. Die methodischen Grundlagen fuer die Nutzung dieses Prinzips unter von vorgesehenen geometrischen und messtechnischen Bedingungen sind Gegenstand dieser Arbeit. (orig.)

  7. Auf dem Weg zu einer ‹vernetzenden› Profession. Theoretisch-konzeptionelle Überlegungen zum Selbstverständnis der Medienpädagogik

    Directory of Open Access Journals (Sweden)

    Kai-Uwe Hugger

    2017-06-01

    Full Text Available In die Professionalisierungsdebatte der erziehungswissenschaftlichen Disziplin gehört auch die Auseinandersetzung mit dem Selbstverständnis der Medienpädagogik bzw. des Medienpädagogen. Die Medienpädagogische Professionalisierungsdiskussion stellt daher für den Autor gleichzeitig die Basis für einen Klärungsversuch einer medienpädagogischen Identität dar. Er beschreibt und analysiert Professionalisierungsstrategien aufgrund von vier Konzepten medienpädagogischer Professionalität: der beschützend-wertevermittelnde, der gesellschaftskritisch-wissenschaftszentrierte, der bildungstechnologisch-opitimierende und der vernetzte Medienpädagoge. Über den Begriff der Medienkompetenz nach Baacke stellt er zentrale Eckpunkte einer Struktur medienpädagogischen Handelns auf. (DIPF/Orig..

  8. The Nucleation of Protein Aggregates - From Crystals to Amyloid Fibrils.

    Science.gov (United States)

    Buell, Alexander K

    2017-01-01

    The condensation and aggregation of individual protein molecules into dense insoluble phases is of relevance in such diverse fields as materials science, medicine, structural biology and pharmacology. A common feature of these condensation phenomena is that they usually are nucleated processes, i.e. the first piece of the condensed phase is energetically costly to create and hence forms slowly compared to its subsequent growth. Here we give a compact overview of the differences and similarities of various protein nucleation phenomena, their theoretical description in the framework of colloid and polymer science and their experimental study. Particular emphasis is put on the nucleation of a specific type of filamentous protein aggregates, amyloid fibrils. The current experimentally derived knowledge on amyloid fibril nucleation is critically assessed, and we argue that it is less advanced than is generally believed. This is due to (I) the lack of emphasis that has been put on the distinction between homogeneous and heterogeneous nucleation in experimental studies (II) the use of oversimplifying and/or inappropriate theoretical frameworks for the analysis of kinetic data of amyloid fibril nucleation. A strategy is outlined and advocated of how our understanding of this important class of processes can be improved in the future. © 2017 Elsevier Inc. All rights reserved.

  9. Imaging and quantification of amyloid fibrillation in the cell nucleus.

    Science.gov (United States)

    Arnhold, Florian; Scharf, Andrea; von Mikecz, Anna

    2015-01-01

    Xenobiotics, as well as intrinsic processes such as cellular aging, contribute to an environment that constantly challenges nuclear organization and function. While it becomes increasingly clear that proteasome-dependent proteolysis is a major player, the topology and molecular mechanisms of nuclear protein homeostasis remain largely unknown. We have shown previously that (1) proteasome-dependent protein degradation is organized in focal microenvironments throughout the nucleoplasm and (2) heavy metals as well as nanoparticles induce nuclear protein fibrillation with amyloid characteristics. Here, we describe methods to characterize the landscape of intranuclear amyloid on the global and local level in different systems such as cultures of mammalian cells and the soil nematode Caenorhabditis elegans. Application of discrete mathematics to imaging data is introduced as a tool to develop pattern recognition of intracellular protein fibrillation. Since stepwise fibrillation of otherwise soluble proteins to insoluble amyloid-like protein aggregates is a hallmark of neurodegenerative protein-misfolding disorders including Alzheimer's disease, CAG repeat diseases, and the prion encephalopathies, investigation of intracellular amyloid may likewise aid to a better understanding of the pathomechanisms involved. We consider aggregate profiling as an important experimental approach to determine if nuclear amyloid has toxic or protective roles in various disease processes.

  10. Artificial Intelligence Methods Applied to Parameter Detection of Atrial Fibrillation

    Science.gov (United States)

    Arotaritei, D.; Rotariu, C.

    2015-09-01

    In this paper we present a novel method to develop an atrial fibrillation (AF) based on statistical descriptors and hybrid neuro-fuzzy and crisp system. The inference of system produce rules of type if-then-else that care extracted to construct a binary decision system: normal of atrial fibrillation. We use TPR (Turning Point Ratio), SE (Shannon Entropy) and RMSSD (Root Mean Square of Successive Differences) along with a new descriptor, Teager- Kaiser energy, in order to improve the accuracy of detection. The descriptors are calculated over a sliding window that produce very large number of vectors (massive dataset) used by classifier. The length of window is a crisp descriptor meanwhile the rest of descriptors are interval-valued type. The parameters of hybrid system are adapted using Genetic Algorithm (GA) algorithm with fitness single objective target: highest values for sensibility and sensitivity. The rules are extracted and they are part of the decision system. The proposed method was tested using the Physionet MIT-BIH Atrial Fibrillation Database and the experimental results revealed a good accuracy of AF detection in terms of sensitivity and specificity (above 90%).

  11. Artificially modified collagen fibril orientation affects leather tear strength.

    Science.gov (United States)

    Kelly, Susyn J; Wells, Hannah C; Sizeland, Katie H; Kirby, Nigel; Edmonds, Richard L; Ryan, Tim; Hawley, Adrian; Mudie, Stephen; Haverkamp, Richard G

    2018-07-01

    Ovine leather has around half the tear strength of bovine leather and is therefore not suitable for high-value applications such as shoes. Tear strength has been correlated with the natural collagen fibril alignment (orientation index, OI). It is hypothesized that it could be possible to artificially increase the OI of the collagen fibrils and that an artificial increase in OI could increase tear strength. Ovine skins, after pickling and bating, were strained biaxially during chrome tanning. The strain ranged from 2 to 15% of the initial sample length, either uniformly in both directions by 10% or with 3% in one direction and 15% in the other. Once tanned, the leather tear strengths were measured and the collagen fibril orientation was measured using synchrotron-based small-angle X-ray scattering. The OI increased as a result of strain during tanning from 0.48 to 0.79 (P = 0.001) measured edge-on and the thickness-normalized tear strength increased from 27 to 43 N mm -1 (P leather was strained 10% in two orthogonal directions. This is evidence to support a causal relationship between high OI (measured edge-on), highly influenced by thickness, and tear strength. It also provides a method to produce stronger leather. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. Potent inhibition of tau fibrillization with a multivalent ligand

    International Nuclear Information System (INIS)

    Honson, Nicolette S.; Jensen, Jordan R.; Darby, Michael V.; Kuret, Jeff

    2007-01-01

    Small-molecule inhibitors of tau fibrillization are under investigation as tools for interrogating the tau aggregation pathway and as potential therapeutic agents for Alzheimer's disease. Established inhibitors include thiacarbocyanine dyes, which can inhibit recombinant tau fibrillization in the presence of anionic surfactant aggregation inducers. In an effort to increase inhibitory potency, a cyclic bis-thiacarbocyanine molecule containing two thiacarbocyanine moieties was synthesized and characterized with respect to tau fibrillization inhibitory activity by electron microscopy and ligand aggregation state by absorbance spectroscopy. Results showed that the inhibitory activity of the bis-thiacarbocyanine was qualitatively similar to a monomeric cyanine dye, but was more potent with 50% inhibition achieved at ∼80 nM concentration. At all concentrations tested in aqueous solution, the bis-thiacarbocyanine collapsed to form a closed clamshell structure. However, the presence of tau protein selectively stabilized the open conformation. These results suggest that the inhibitory activity of bis-thiacarbocyanine results from multivalency, and reveal a route to more potent tau aggregation inhibitors

  13. Maze Procedures for Atrial Fibrillation, From History to Practice.

    Science.gov (United States)

    Kik, Charles; Bogers, Ad J J C

    2011-10-01

    Atrial fibrillation may result in significant symptoms, (systemic) thrombo-embolism, as well as tachycardia-induced cardiomyopathy with cardiac failure, and consequently be associated with significant morbidity and mortality. Nowadays symptomatic atrial fibrillation can be treated with catheter-based ablation, surgical ablation or hybrid approaches. In this setting a fairly large number of surgical approaches and procedures are described and being practised. It should be clear that the Cox-maze procedure resulted from building up evidence and experience in different steps, while some of the present surgical approaches and techniques are being based only on technical feasibility with limited experience, rather than on a process of consequent methodology. Some of the issues still under debate are whether or not the maze procedure can be limited to the left atrium or even to isolation of the pulmonary veins or that bi-atrial procedures are indicated, whether or not cardiopulmonary bypass is to be applied and which route of exposure facilitates an optimal result. In addition, maze procedures are not procedures guide by electrophysiological mapping. At least in theory not in all patients all lesions of the maze procedures are necessary. A history and aspects of current practise in surgical treatment of atrial fibrillation is presented.

  14. Managing atrial fibrillation in the elderly: critical appraisal of dronedarone.

    Science.gov (United States)

    Trigo, Paula; Fischer, Gregory W

    2012-01-01

    Atrial fibrillation is the most commonly seen arrhythmia in the geriatric population and is associated with increased cardiovascular morbidity and mortality. Treatment of the elderly with atrial fibrillation remains challenging for physicians, because this unique subpopulation is characterized by multiple comorbidities requiring chronic use of numerous medications, which can potentially lead to severe drug interactions. Furthermore, age-related changes in the cardiovascular system as well as other physiological changes result in altered drug pharmacokinetics. Dronedarone is a new drug recently approved for the treatment of arrhythmias, such as atrial fibrillation and/or atrial flutter. Dronedarone is a benzofuran amiodarone analog which lacks the iodine moiety and contains a methane sulfonyl group that decreases its lipophilicity. These differences in chemical structure are responsible for making dronedarone less toxic than amiodarone which, in turn, results in fewer side effects. Adverse events for dronedarone include gastrointestinal side effects and rash. No dosage adjustments are required for patients with renal impairment. However, the use of dronedarone is contraindicated in the presence of severe hepatic dysfunction.

  15. Cost of illness of atrial fibrillation: a nationwide study of societal impact.

    Science.gov (United States)

    Johnsen, Søren Paaske; Dalby, Lene Worsaae; Täckström, Tomas; Olsen, Jens; Fraschke, Anina

    2017-11-10

    The prevalence of atrial fibrillation is increasing rapidly; however, to date, population-based data are lacking on the attributable cost of illness of atrial fibrillation from a societal perspective, including both direct and indirect costs. The study was an incidence-based cost-of-illness study based on national registries covering the entire population of Denmark. We identified all patients with a first-time hospital diagnosis of atrial fibrillation between 2001 and 2012. For every atrial fibrillation patient, we identified three age- and sex-matched controls from the general population. Both the total and the attributable costs of atrial fibrillation were estimated based on individual level information on hospital care (in- and out-patient contacts), primary sector care, use of prescription drugs and productivity loss. Average 3-year societal costs per patient attributable to atrial fibrillation were estimated to be €20,403-26,544 during the study period. The costs were highest during the first year after diagnosis of atrial fibrillation. Admission costs constituted the largest cost component, whereas primary sector costs and medicine costs only constituted minor components. The attributable costs were more than two-fold higher among patients experiencing a stroke. The total 3-year cost attributable to atrial fibrillation in Denmark was estimated to be €219-295 million. The societal costs attributable to atrial fibrillation are significant. Reducing the need for hospitalizations, in particular from stroke, is a key factor in controlling the costs.

  16. Iowa Mutant Apolipoprotein A-I (ApoA-IIowa) Fibrils Target Lysosomes.

    Science.gov (United States)

    Kameyama, Hirokazu; Nakajima, Hiroyuki; Nishitsuji, Kazuchika; Mikawa, Shiho; Uchimura, Kenji; Kobayashi, Norihiro; Okuhira, Keiichiro; Saito, Hiroyuki; Sakashita, Naomi

    2016-07-28

    The single amino acid mutation G26R in human apolipoprotein A-I (apoA-IIowa) is the first mutation that was associated with familial AApoA1 amyloidosis. The N-terminal fragments (amino acid residues 1-83) of apoA-I containing this mutation deposit as amyloid fibrils in patients' tissues and organs, but the mechanisms of cellular degradation and cytotoxicity have not yet been clarified. In this study, we demonstrated degradation of apoA-IIowa fibrils via the autophagy-lysosomal pathway in human embryonic kidney 293 cells. ApoA-IIowa fibrils induced an increase in lysosomal pH and the cytosolic release of the toxic lysosomal protease cathepsin B. The mitochondrial dysfunction caused by apoA-IIowa fibrils depended on cathepsin B and was ameliorated by increasing the degradation of apoA-IIowa fibrils. Thus, although apoA-IIowa fibril transport to lysosomes and fibril degradation in lysosomes may have occurred, the presence of an excess number of apoA-IIowa fibrils, more than the lysosomes could degrade, may be detrimental to cells. Our results thus provide evidence that the target of apoA-IIowa fibrils is lysosomes, and we thereby gained a novel insight into the mechanism of AApoA1 amyloidosis.

  17. Investigations of co-combustion of plastics in a coal dust furnace; Untersuchungen zur Mitverbrennung von Kunststoffen in einer Kohlestaubfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, T.; Spliethoff, H.; Hein, K.R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen (IVD); Christill, M.; Kicherer, A.; Seifert, H. [BASF AG, Verfahrenstechnik-ZET/EH-L544, Ludwigshafen am Rhein (Germany)

    1996-12-31

    In a cooperation project of the Institute of Process Engineering and Power Plant TEchnology (IVD) at the University of Stuttgart and the BASF AG, investigations of co-combustion of plastic material in a coal dust furnace were carried out. The central question of the research work was the ignition and burnout of the particles in dependence of the residence time in the hot part of the furnace. Particle sizes were varied with the aim to define the largest possible particle size in order to minimize the cost of fuel preparation by grinding. On the other hand, tests were made with pure materials and synthetic mixtures of these in order to characterize the influence of different types of plastic. The investigations showed that plastics are suited as fuels for coal dust furnaces, and that the cost of fuel preparation can be reduced to an acceptable level. With polyethylene, which is difficult to ignite, an upper particle size limit of 1.25 to 1.5 mm was reached in the IVD test stand. In industrial applications with a different burner arrangement, even better results may be expected. (orig/AKB) [Deutsch] In einer Zusammenarbeit zwischen dem Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart und der BASF AG wurden Versuche zur Coverbrennung von Kunststoffen in einer Kohlenstaubfeuerung durchgefuehrt. Im Mittelpunkt der Untersuchungen standen Zuendung und Abbrand der Kunststoffpartikel in Abhaengigkeit von der Verweilzeit im heissen Bereich der Brennkanner. Variiert wurden hierzu zum einen die Partikelgroessen mit dem Ziel, den Aufbereitungsaufwand durch Zerkleinerung zu minimieren. Zur Charakterisierung der Einfluesse verschiedener Kunststoffarten wurden die Versuche mit unterschiedlichen Reinkunststoffen und synthetischen Mischungen durchgefuehrt. Die Versuche zeigen, dass sich Kunststoffe mit vertretbarem Mahlaufwand in der Staubfeuerung einsetzen lassen. Am Beispiel des Polyethylen, eines der thermogravimetrischen Analyse nach relativ

  18. Simulation and experimental validation of the performance of a absorption refrigerator; Simulation und experimentelle Validierung des Betriebsverhaltens einer Absorptionskaeltemaschine

    Energy Technology Data Exchange (ETDEWEB)

    Olbricht, Michael; Luke, Andrea [Kassel Univ. (Germany). Fachgebiet Technische Thermodynamik

    2015-07-01

    The two biggest obstacles to a stronger market penetration of absorption refrigerators are their high cost and the size of the apparatus, which are due to the inaccurate methods for plant design. In order to contribute to an improved design a thermodynamic model is presented to describe the performance of a absorption refrigerator with the working fluid water/lithium. In this model, the processes are displayed in the single apparatus and coupled to each other in the systemic context. Thereby the interactions between the apparatus can specifically investigated and thus the process limiting component can be identified under the respective conditions. A validation of the simulation model and the boundary conditions used is done based on experimental data operating a self-developed absorption refrigerator. In the simulation, the heat transfer surfaces in accordance with the real system can be specified. The heat transport is taken into account based on typical values for the heat transfer in the individual apparatuses. Simulation results show good agreement with the experimental data. The physical relationships and influences externally defined operating parameters are correctly reproduced. Due to the chosen low heat transfer coefficient, the calculated cooling capacities by the model are below the experimentally measured. Finally, the possibilities and limitations are discussed by using the model and further improvement possibilities are suggested. [German] Die beiden groessten Hemmnisse fuer eine staerkere Marktdurchdringung von Absorptionskaeltemaschinen (AKM) sind deren hohe Anschaffungskosten sowie die Baugroesse der Apparate, die durch die ungenauen Methoden zur Anlagenauslegung begruendet sind. Als Beitrag fuer eine verbesserte Auslegung wird ein thermodynamisches Modell zur Beschreibung des Betriebsverhaltens einer AKM mit dem Arbeitsstoffpaar Wasser/Lithiumbromid vorgestellt. In diesem werden die Prozesse in den Einzelapparaten abgebildet und im systemischen

  19. Investigations of co-combustion of plastics in a coal dust furnace; Untersuchungen zur Mitverbrennung von Kunststoffen in einer Kohlestaubfeuerung

    Energy Technology Data Exchange (ETDEWEB)

    Gerhardt, T; Spliethoff, H; Hein, K R.G. [Stuttgart Univ. (Germany). Inst. fuer Verfahrenstechnik und Dampfkesselwesen (IVD); Christill, M; Kicherer, A; Seifert, H [BASF AG, Verfahrenstechnik-ZET/EH-L544, Ludwigshafen am Rhein (Germany)

    1997-12-31

    In a cooperation project of the Institute of Process Engineering and Power Plant TEchnology (IVD) at the University of Stuttgart and the BASF AG, investigations of co-combustion of plastic material in a coal dust furnace were carried out. The central question of the research work was the ignition and burnout of the particles in dependence of the residence time in the hot part of the furnace. Particle sizes were varied with the aim to define the largest possible particle size in order to minimize the cost of fuel preparation by grinding. On the other hand, tests were made with pure materials and synthetic mixtures of these in order to characterize the influence of different types of plastic. The investigations showed that plastics are suited as fuels for coal dust furnaces, and that the cost of fuel preparation can be reduced to an acceptable level. With polyethylene, which is difficult to ignite, an upper particle size limit of 1.25 to 1.5 mm was reached in the IVD test stand. In industrial applications with a different burner arrangement, even better results may be expected. (orig/AKB) [Deutsch] In einer Zusammenarbeit zwischen dem Institut fuer Verfahrenstechnik und Dampfkesselwesen (IVD) der Universitaet Stuttgart und der BASF AG wurden Versuche zur Coverbrennung von Kunststoffen in einer Kohlenstaubfeuerung durchgefuehrt. Im Mittelpunkt der Untersuchungen standen Zuendung und Abbrand der Kunststoffpartikel in Abhaengigkeit von der Verweilzeit im heissen Bereich der Brennkanner. Variiert wurden hierzu zum einen die Partikelgroessen mit dem Ziel, den Aufbereitungsaufwand durch Zerkleinerung zu minimieren. Zur Charakterisierung der Einfluesse verschiedener Kunststoffarten wurden die Versuche mit unterschiedlichen Reinkunststoffen und synthetischen Mischungen durchgefuehrt. Die Versuche zeigen, dass sich Kunststoffe mit vertretbarem Mahlaufwand in der Staubfeuerung einsetzen lassen. Am Beispiel des Polyethylen, eines der thermogravimetrischen Analyse nach relativ

  20. Über das Sicherstellen von Güte/Validität im Rahmen einer multi-lokalen und multidisziplinären Studie

    OpenAIRE

    Crawford, H. Ken; Leybourne, Marnie L.; Arnott, Allan

    2000-01-01

    Qualitative Forschung wird häufig wegen ihres Mangels an Güte kritisiert. Um diese Situation zu verbessern, werden in der Literatur Kriterien wie "trustworthiness", "dependability" und "reliability" diskutiert. Im vorliegenden Beitrag werden Vorschläge zu dieser Debatte ausgehend von einer empirischen Untersuchung zu den Lernprozessen von australischen Farmern gemacht. An dieser Interviewstudie, die in drei Bundesstaaten durchgeführt wurde, waren Forschende unterschiedlicher Disziplinen betei...

  1. Stellenwert einer kombinierten Therapie von 5-HT3-Antagonisten und Alizaprid in der Behandlung von verzögertem Chemotherapie-induziertem Erbrechen

    OpenAIRE

    Haar, Ivonne Elisabeth

    2003-01-01

    Hintergrund der Studie: Obwohl 5-HT3-Rezeptorantagonisten gute Wirksamkeit zeigen in der Kontrolle von Übelkeit und Erbrechen in der akuten Phase nach cisplatinhaltiger Chemotherapie, konnte diese Kontrolle in der verzögerten Phase bisher nicht erreicht werden. Die vorliegende Studie sollte aufzeigen, ob es bei dem Zusatz eines 5-HT3-Antagonisten, in diesem Fall Ondansetron, zu dem Dopaminantagonisten Alizaprid zu einer Effektivitätssteigerung der antiemetischen Therapie in der verzögerten...

  2. Entwicklung und Evaluierung eines auf dem Stellungsfeldermodell basierenden syntaktischen Annotationsverfahrens für Lernerkorpora innerhalb einer Mehrebenen-Architektur mit Schwerpunkt auf schriftlichen Texten fortgeschrittener Deutschlerner

    OpenAIRE

    Doolittle, Seanna

    2008-01-01

    Die Arbeit zeigt exemplarisch die Möglichkeiten, die die Mehrebenen-Korpusarchitektur bei der Annotation von „standard-“ und „nicht standardsprachlichen“ Äußerungen in einem gemeinsamen Korpus bieten. // Konkret beschäftigt sie sich mit der Entwicklung und Evaluierung eines auf dem Stellungsfeldermodell basierenden syntaktischen Annotationsverfahrens für Lernerkorpora, bestehend aus schriftlichen Texten fortgeschrittener Deutschlerner, innerhalb einer Mehrebenen-Architektur. Die Felderannotat...

  3. Profitability aspects of combined power/heat plants based on the example of a gas turbine; Wirtschaftlichkeitsbetrachtungen ueber KWK-Anlagen am Beispiel einer Gasturbine

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, W. [Thyssengas GmbH, Duisburg (Germany)

    1998-04-01

    The efficiency of a combined power/heat plant is treated in an example relating to a gas turbine. An important prior condition for optimum planning of a combined power/heat plant is assessment of the current position in addition to a demand analysis. Constituting a vital planning instrument for the process are systematic annual continuous curves in respect of electricity and heat. Aided by a PC software program it is possible, on the basis of a few key figures, to establish whether a detailed study is able to bring about any economical solution. In addition, a primary-energy and emission balance-sheet is compiled illustrating the advantages to be gained from combined power/heat systems of relevance to the environment. A sensitivity analysis shows main influential factors exercised on the efficiency of the gas turbine project. As might be expected, the greatest influenc eon profitability comes from the electricity proceeds, the price of fuel and capital costs. Finally, different financing models for combined power/heat plants are discussed along with a price safeguarding method. (orig.) [Deutsch] Die Wirtschaftlichkeit einer KWK-Anlage wird am Beispiel einer Gasturbine erlaeutert. Wichtige Voraussetzung fuer die optimale Planung einer KWK-Anlage ist die Bestandsaufnahme mit Bedarfsanalyse. Ein entscheidendes Planungsinstrument stellen hierbei geordnete Jahresdauerlinien fuer Strom und Waerme dar. Mit Hilfe eines PC-Programms kann anhand weniger Eckdaten festgestellt werden, ob eine Detailbetrachtung zu einer wirtschaftlichen Loesung fuehren koennte. Zusaetzlich wird eine Primaerenergie- und Emissionsbilanz erstellt, die die umweltrelevanten Vorteile der Kraft-Waerme-Kopplung verdeutlicht. Eine Sensitivitaetsanalyse zeigt Haupteinflussfaktoren auf die Wirtschaftlichkeit des Gasturbinenprojektes. Die Stromgutschrift, der Brennstoffpreis und die Investitionskosten ueben erwartungsgemaess den groessten Einfluss auf die Wirtschaftlichkeit aus. Abschliessend werden

  4. QTL-Kartierung und funktionelle Kandidatengenanalyse für das Merkmal Totgeburt in einer fortgeschrittenen Fleckvieh- x Red-Holstein-Rückkreuzungspopulation

    OpenAIRE

    Gomeringer, Verena

    2007-01-01

    Das Ziel dieser Arbeit war die Kartierung eines QTL mit Effekt auf paternalen Kalbeverlauf und paternale Totgeburt auf Bos Taurus Autosom 9 (BTA09) in einer fortgeschrittenen Fleckvieh x Red-Holstein Rückkreuzungspopulation mit positioneller und funktioneller Kandidatengenanalyse. Dazu wurden Untersuchungen mit verschiedenen Kartierungsdesigns in Granddaughter und Daughter Designs durchgeführt. Intervallkartierung und Linkage / Linkage-Disequilibrium-Kartierung wurden verwendet um den QTL ...

  5. Soziale Interaktion, Lebensqualität und Krankheitsverarbeitung bei Akne-Patienten : Fall-Kontroll-Studie mit 32 Akne-Patienten und einer parallelisierten Gruppe Gesunder

    OpenAIRE

    Dittmer, Julia Gesine Erdmute

    2015-01-01

    Hintergrund Acne vulgaris ist mehr als ein vorübergehendes Pubertätsproblem: Sie kann schwere psychische Folgeerscheinungen verursachen. Fragestellung In der vorliegenden zweiarmigen Studie sollten Erkenntnisse zu sozialer Interaktion, Lebensqualität und Krankheitsverarbeitung von Akne-Patienten im Vergleich zu einer gesunden Kontrollgruppe gewonnen werden. Besonderes Interesse galt dabei der sozialen Interaktionsangst und dem Affekt Ekel. Ferner wurde die Entwicklung der genannten P...

  6. Intraoperative Inducibility of Atrial Fibrillation Does Not Predict Early Postoperative Atrial Fibrillation.

    Science.gov (United States)

    Lanters, Eva A H; Teuwen, Christophe P; Yaksh, Ameeta; Kik, Charles; van der Does, Lisette J M E; Mouws, Elisabeth M J P; Knops, Paul; van Groningen, Nicole J; Hokken, Thijmen; Bogers, Ad J J C; de Groot, Natasja M S

    2018-03-10

    Early postoperative atrial fibrillation (EPoAF) is associated with thromboembolic events, prolonged hospitalization, and development of late PoAF (LPoAF). It is, however, unknown if EPoAF can be predicted by intraoperative AF inducibility. The aims of this study are therefore to explore (1) the value of intraoperative inducibility of AF for development of both EPoAF and LPoAF and (2) the predictive value of de novo EPoAF for recurrence of LPoAF. Patients (N=496, 75% male) undergoing cardiothoracic surgery for coronary and/or valvular heart disease were included. AF induction was attempted by atrial pacing, before extracorporeal circulation. All patients were on continuous rhythm monitoring until discharge to detect EPoAF. During a follow-up period of 2 years, LPoAF was detected by ECGs and Holter recordings. Sustained AF was inducible in 56% of patients. There was no difference in patients with or without AF before surgery ( P =0.159), or between different types of surgery ( P =0.687). In patients without a history of AF, incidence of EPoAF and LPoAF was 37% and 2%, respectively. EPoAF recurred in 58% patients with preoperative AF, 53% developed LPoAF. There were no correlations between intraoperative inducibility and EPoAF or LPoAF ( P >0.05). EPoAF was not correlated with LPoAF in patients without a history of AF ( P =0.116), in contrast to patients with AF before surgery ( P <0.001). Intraoperative AF inducibility does not predict development of either EPoAF or LPoAF. In patients with AF before surgery, EPoAF is correlated with LPoAF recurrences. This correlation is absent in patients without AF before surgery. © 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  7. Amyloid-like fibril formation by polyQ proteins: a critical balance between the polyQ length and the constraints imposed by the host protein.

    Directory of Open Access Journals (Sweden)

    Natacha Scarafone

    Full Text Available Nine neurodegenerative disorders, called polyglutamine (polyQ diseases, are characterized by the formation of intranuclear amyloid-like aggregates by nine proteins containing a polyQ tract above a threshold length. These insoluble aggregates and/or some of their soluble precursors are thought to play a role in the pathogenesis. The mechanism by which polyQ expansions trigger the aggregation of the relevant proteins remains, however, unclear. In this work, polyQ tracts of different lengths were inserted into a solvent-exposed loop of the β-lactamase BlaP and the effects of these insertions on the properties of BlaP were investigated by a range of biophysical techniques. The insertion of up to 79 glutamines does not modify the structure of BlaP; it does, however, significantly destabilize the enzyme. The extent of destabilization is largely independent of the polyQ length, allowing us to study independently the effects intrinsic to the polyQ length and those related to the structural integrity of BlaP on the aggregating properties of the chimeras. Only chimeras with 55Q and 79Q readily form amyloid-like fibrils; therefore, similarly to the proteins associated with diseases, there is a threshold number of glutamines above which the chimeras aggregate into amyloid-like fibrils. Most importantly, the chimera containing 79Q forms amyloid-like fibrils at the same rate whether BlaP is folded or not, whereas the 55Q chimera aggregates into amyloid-like fibrils only if BlaP is unfolded. The threshold value for amyloid-like fibril formation depends, therefore, on the structural integrity of the β-lactamase moiety and thus on the steric and/or conformational constraints applied to the polyQ tract. These constraints have, however, no significant effect on the propensity of the 79Q tract to trigger fibril formation. These results suggest that the influence of the protein context on the aggregating properties of polyQ disease-associated proteins could be

  8. Looking into the causes of deformation processes: The example of an industrial-scale turbine; Ursachenerforschung bei Deformationsprozessen am Beispiel einer Grossturbine

    Energy Technology Data Exchange (ETDEWEB)

    Pfeufer, A [Hannover Univ. (Germany). Geodaetisches Inst.

    1997-12-31

    While quasistatic and kinematic methods for analysis and interpretation of deformation processes reached technical maturity long ago, dynamic models are still in the early development phase. Starting from an outline of the current state of knowledge and a proposal on the definition `Dynamic models`, two fundamentally different dynamic model approaches are described and discussed, i.e. input-output models and state models. Input-output models are discussed in some detail, and the results of such a model when applied to investigations of the deformation characteristics of an industria-scale turbine are presented. (orig.) [Deutsch] Waehrend im Bereich der s.g. quasi-statischen und kinematischen Verfahrensentwicklung zur Analyse und Interpretation von Deformationsprozessen nur noch wenige Verfeinerungen zu erwarten sind, steht man bei der Bereitstellung praxisreifer dynamischer Modelle noch weitestgehend am Anfang einer vielversprechenden Entwicklungsphase. Ausgehend von einem kurzen Ueberblick zum aktuellen Entwicklungsstand und einem Vorschlag zur Definition `Dynamischer Modelle` werden zwei grundsaetzlich verschiedene dynamische Modellansaetze - die Ein-Ausgangs-Modelle und Zustandsmodelle - beschrieben und bezueglich ihrer Vor- und Nachteile diskutiert. Nach einer tiefgruendigeren Behandlung von Ein-Ausgangs-Modellen folgen Ergebnisse der Anwendung eines solchen Modellansatzes zur Untersuchung des Deformationsverhaltens einer Grossturbine. (orig.)

  9. Looking into the causes of deformation processes: The example of an industrial-scale turbine; Ursachenerforschung bei Deformationsprozessen am Beispiel einer Grossturbine

    Energy Technology Data Exchange (ETDEWEB)

    Pfeufer, A. [Hannover Univ. (Germany). Geodaetisches Inst.

    1996-12-31

    While quasistatic and kinematic methods for analysis and interpretation of deformation processes reached technical maturity long ago, dynamic models are still in the early development phase. Starting from an outline of the current state of knowledge and a proposal on the definition `Dynamic models`, two fundamentally different dynamic model approaches are described and discussed, i.e. input-output models and state models. Input-output models are discussed in some detail, and the results of such a model when applied to investigations of the deformation characteristics of an industria-scale turbine are presented. (orig.) [Deutsch] Waehrend im Bereich der s.g. quasi-statischen und kinematischen Verfahrensentwicklung zur Analyse und Interpretation von Deformationsprozessen nur noch wenige Verfeinerungen zu erwarten sind, steht man bei der Bereitstellung praxisreifer dynamischer Modelle noch weitestgehend am Anfang einer vielversprechenden Entwicklungsphase. Ausgehend von einem kurzen Ueberblick zum aktuellen Entwicklungsstand und einem Vorschlag zur Definition `Dynamischer Modelle` werden zwei grundsaetzlich verschiedene dynamische Modellansaetze - die Ein-Ausgangs-Modelle und Zustandsmodelle - beschrieben und bezueglich ihrer Vor- und Nachteile diskutiert. Nach einer tiefgruendigeren Behandlung von Ein-Ausgangs-Modellen folgen Ergebnisse der Anwendung eines solchen Modellansatzes zur Untersuchung des Deformationsverhaltens einer Grossturbine. (orig.)

  10. Imaging β-amyloid fibrils in Alzheimer's disease: a critical analysis through simulation of amyloid fibril polymerization

    International Nuclear Information System (INIS)

    Shoghi-Jadid, Kooresh; Barrio, Jorge R.; Kepe, Vladimir; Wu, H.-M.; Small, Gary W.; Phelps, Michael E.; Huang, S.-C.

    2005-01-01

    The polymerization of β-amyloid (Aβ) peptides into fibrillary plaques is implicated, in part, in the pathogenesis of Alzheimer's disease. Aβ molecular imaging probes (Aβ-MIPs) have been introduced in an effort to quantify amyloid burden or load, in subjects afflicted with AD by invoking the classic PET receptor model for the quantitation of neuronal receptor density. In this communication, we explore conceptual differences between imaging the density of amyloid fibril polymers and neuronal receptors. We formulate a mathematical model for the polymerization of Aβ with parameters that are mapped to biological modulators of fibrillogenesis and introduce a universal measure for amyloid load to accommodate various interactions of Aβ-MIPs with fibrils. Subsequently, we hypothesize four Aβ-MIPs and utilize the fibrillogenesis model to simulate PET tissue time activity curves (TACs). Given the unique nature of polymer growth and resulting PET TAC, the four probes report differing amyloid burdens for a given brain pathology, thus complicating the interpretation of PET images. In addition, we introduce the notion of an MIP's resolution, apparent maximal binding site concentration, optimal kinetic topology and its resolving power in characterizing the pathological progression of AD and the effectiveness of drug therapy. The concepts introduced in this work call for a new paradigm that goes beyond the classic parameters B max and K D to include binding characteristics to polymeric peptide aggregates such as amyloid fibrils, neurofibrillary tangles and prions

  11. Core sequence of PAPf39 amyloid fibrils and mechanism of pH-dependent fibril formation: the role of monomer conformation.

    Science.gov (United States)

    French, Kinsley C; Makhatadze, George I

    2012-12-21

    PAPf39, a 39-residue peptide fragment from human prostatic acidic phosphatase, has been shown to form amyloid fibrils in semen (SEVI), which increase HIV infectivity by up to 5 orders of magnitude. The sequence of the PAPf39 fibrillar core was identified using hydrogen-deuterium exchange (HDX) mass spectrometry and protease protection assays. The central and C-terminal regions are highly protected from HDX and proteolytic cleavage and, thus, are part of the fibrillar core. Conversely, the N-terminal region is unprotected from HDX and proteolytic cleavage, suggesting that it is exposed and not part of the fibrillar core. This finding was tested using two N-terminal truncated variants, PAPf39Δ1-8 and PAPf39Δ1-13. Both variants formed amyloid fibrils at neutral pH. However, these variants showed a markedly different pH dependence of fibril formation versus that of PAPf39. PAPf39 fibrils can form at pH 7.7, but not at pH 5.5 or 2.5, while both N-terminally truncated variants can form fibrils at these pH values. Thus, the N-terminal region is not necessary for fibril formation but modulates the pH dependence of PAPf39 fibril formation. PAPf39Δ1-8 and PAPf39Δ1-13 are capable of seeding PAPf39 fibril formation at neutral pH, suggesting that these variants are structurally compatible with PAPf39, yet no mixed fibril formation occurs between the truncated variants and PAPf39 at low pH. This suggests that pH affects the PAPf39 monomer conformational ensemble, which is supported by far-UV circular dichroism spectroscopy. A conceptual model describing the pH dependence of PAPf39 aggregation is proposed and provides potential biological implications.

  12. Contrast media in renal insufficiency - risk and prevention; Auswirkungen einer intravasalen Roentgenkontrastmittelgabe auf die Nierenfunktion - Risiken und Praevention

    Energy Technology Data Exchange (ETDEWEB)

    Erley, C.M.; Bader, B.D. [Tuebingen Univ. (Germany). Abt. fuer Innere Medizin III

    2000-10-01

    The use of iodinated contrast media (CM) continues to be a common cause of hospital-acquired acute renal failure (ARF) and its development increases the in-hospital mortality significantly. Alterations in renal hemodynamics and direct tubular toxicity by contrast media are the primary factors believed to be responsible for contrast media-associated nephrotoxicity. We review recent insights into the pathogenesis of this complication and summarize prophylacttic strategies focussing on hydration, vasoactive pharmacological agents, alternative contrast media and 'prophylactic hemodialysis'. (orig.) [German] Das durch Roentgenkontrastmittelgabe initiierte Nierenversagen, die sogenannte Kontrastmittelnephropathie (KMN), stellt - insbesondere bei Patienten mit eingeschraekuter Nierenfunktion - nach wie vor ein erhebliches medizinisches Problem dar, dessen Auftreten mit einer deutlich erhoehten Krankenhausmortalitaet verbunden ist. Die Genese der KMN ist nach wie vor nicht eindeutig geklaert. Neben haemodynamischen Veraenderungen durch die Kontrastmittel spielen tubulotoxische Schaeden eine Rolle. Die vorliegende Uebersicht beschreibt die zur Zeit bekannten pathophysiologischen Vorgaenge bei der KMN und die moeglichen Praeventivmassnahmen mit besonderem Augenmerk auf die klinisch relevanten Themen der Hydratation, der prophylaktischen Gabe vasoaktiver Substanzen, den Einsatz alternativer Kontrastmittel und die Entfernung von Roentgenkontrastmitteln (KM) mittels Haemodialyse. (orig.)

  13. Forschende und ihre Daten: Ergebnisse einer österreichweiten Befragung. Report 2015 – Executive Summary und Empfehlungen

    Directory of Open Access Journals (Sweden)

    Bruno Bauer

    2015-01-01

    Full Text Available Der vorliegende Beitrag bringt Executive Summary und Empfehlungen aus „Forschende und ihre Daten: Ergebnisse einer österreichweiten Befragung. Report 2015“. Dieser Report gibt einen Überblick über die österreichweite Befragung zu Forschungsdaten, die im Rahmen des Projekts e-Infrastructures Austria 2015 durchgeführt wurde. Diese richtete sich an das wissenschaftliche und künstlerisch-wissenschaftliche Personal aller 21 öffentlichen Universitäten sowie an drei außeruniversitäre Forschungseinrichtungen in Österreich. Die Teilnehmenden wurden zu folgenden Themenbereichen befragt: Datentypen und Formate; Datenarchivierung, -sicherung und -verlust; ethische und rechtliche Aspekte; Zugänglichkeit und Nachnutzung; Infrastruktur und Services. Die in diesem Kontext erstmals auf nationaler Ebene durchgeführte Befragung diente der Erhebung des praktischen Umgangs mit Forschungsdaten in Österreich und ist somit die Basis für eine konsekutive Optimierung der zweckdienlichen Infrastruktur, für eine Anpassung der Serviceangebote sowie für eine Neuorientierung bei der Ermittlung von Ressourcen in diesem strategischen Bereich entsprechend der geäußerten Bedürfnisse der im Forschungsprozess Tätigen.

  14. Role of sequence and structural polymorphism on the mechanical properties of amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Gwonchan Yoon

    Full Text Available Amyloid fibrils playing a critical role in disease expression, have recently been found to exhibit the excellent mechanical properties such as elastic modulus in the order of 10 GPa, which is comparable to that of other mechanical proteins such as microtubule, actin filament, and spider silk. These remarkable mechanical properties of amyloid fibrils are correlated with their functional role in disease expression. This suggests the importance in understanding how these excellent mechanical properties are originated through self-assembly process that may depend on the amino acid sequence. However, the sequence-structure-property relationship of amyloid fibrils has not been fully understood yet. In this work, we characterize the mechanical properties of human islet amyloid polypeptide (hIAPP fibrils with respect to their molecular structures as well as their amino acid sequence by using all-atom explicit water molecular dynamics (MD simulation. The simulation result suggests that the remarkable bending rigidity of amyloid fibrils can be achieved through a specific self-aggregation pattern such as antiparallel stacking of β strands (peptide chain. Moreover, we have shown that a single point mutation of hIAPP chain constituting a hIAPP fibril significantly affects the thermodynamic stability of hIAPP fibril formed by parallel stacking of peptide chain, and that a single point mutation results in a significant change in the bending rigidity of hIAPP fibrils formed by antiparallel stacking of β strands. This clearly elucidates the role of amino acid sequence on not only the equilibrium conformations of amyloid fibrils but also their mechanical properties. Our study sheds light on sequence-structure-property relationships of amyloid fibrils, which suggests that the mechanical properties of amyloid fibrils are encoded in their sequence-dependent molecular architecture.

  15. Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients

    Directory of Open Access Journals (Sweden)

    Eduardo Dytz Almeida

    2015-01-01

    Full Text Available Introduction: Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce. Objective: To investigate the arrhythmia subtype of atrial fibrillation and flutter patients in the emergency setting and compare the clinical profile, thromboembolic risk and anticoagulants use. Methods: Cross-sectional retrospective study, with data collection from medical records of every patient treated for atrial fibrillation and flutter in the emergency department of Instituto de Cardiologia do Rio Grande do Sul during the first trimester of 2012. Results: We included 407 patients (356 had atrial fibrillation and 51 had flutter. Patients with paroxysmal atrial fibrillation were in average 5 years younger than those with persistent atrial fibrillation. Compared to paroxysmal atrial fibrillation patients, those with persistent atrial fibrillation and flutter had larger atrial diameter (48.6 ± 7.2 vs. 47.2 ± 6.2 vs. 42.3 ± 6.4; p < 0.01 and lower left ventricular ejection fraction (66.8 ± 11 vs. 53.9 ± 17 vs. 57.4 ± 16; p < 0.01. The prevalence of stroke and heart failure was higher in persistent atrial fibrillation and flutter patients. Those with paroxysmal atrial fibrillation and flutter had higher prevalence of CHADS2 score of zero when compared to those with persistent atrial fibrillation (27.8% vs. 18% vs. 4.9%; p < 0.01. The prevalence of anticoagulation in patients with CHA2DS2-Vasc ≤ 2 was 40%. Conclusions: The population in our registry was similar in its comorbidities and demographic profile to those of North American and European registries. Despite the high thromboembolic risk, the use of anticoagulants was low, revealing difficulties for incorporating guideline recommendations. Public health strategies should be adopted in order to improve these rates.

  16. Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

    Directory of Open Access Journals (Sweden)

    Nathaniel G. N. Milton

    2010-01-01

    Full Text Available The diabetes-associated human islet amyloid polypeptide (IAPP is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ and prion protein (PrP fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  17. Studies of the structure of insulin fibrils by Fourier transform infrared (FTIR) spectroscopy and electron microscopy.

    Science.gov (United States)

    Nielsen, L; Frokjaer, S; Carpenter, J F; Brange, J

    2001-01-01

    Fibril formation (aggregation) of insulin was investigated in acid media by visual inspection, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. Insulin fibrillated faster in hydrochloric acid than in acetic acid at elevated temperatures, whereas the fibrillation tendencies were reversed at ambient temperatures. Electron micrographs showed that bovine insulin fibrils consisted of long fibers with a diameter of 5 to 10 nm and lengths of several microns. The fibrils appeared either as helical filaments (in hydrochloric acid) or arranged laterally in bundles (in acetic acid, NaCl). Freeze-thawing cycles broke the fibrils into shorter segments. FTIR spectroscopy showed that the native secondary structure of insulin was identical in hydrochloric acid and acetic acid, whereas the secondary structure of fibrils formed in hydrochloric acid was different from that formed in acetic acid. Fibrils of bovine insulin prepared by heating or agitating an acid solution of insulin showed an increased content of beta-sheet (mostly intermolecular) and a decrease in the intensity of the alpha-helix band. In hydrochloric acid, the frequencies of the beta-sheet bands depended on whether the fibrillation was induced by heating or agitation. This difference was not seen in acetic acid. Freeze-thawing cycles of the fibrils in hydrochloric acid caused an increase in the intensity of the band at 1635 cm(-1) concomitant with reduction of the band at 1622 cm(-1). The results showed that the structure of insulin fibrils is highly dependent on the composition of the acid media and on the treatment. Copyright 2001 Wiley-Liss Inc. and the American Pharmaceutical Association J Pharm Sci 90: 29-37, 2001

  18. Chances of environmental education. Chancen der Umwelterziehung. Grundlagen einer Umweltpaedagogik und Umweltdidaktik

    Energy Technology Data Exchange (ETDEWEB)

    Schmack, E.

    1982-01-01

    This book constitutes a first basic study on environmental education which integrates itself in the programme and the task of 'chance-opening environmental pedagogics.' The grounds for necessary environmental pedagogics and corresponding pedagogic and didactic reactions are given in a very structural form: - 14 studies present the results of the 'environmental research' of the last decade in a coherent way. - Principles of the present environmental policy are presented and differentiated. - With regard to the evaluation of an 'environmental consciousness' a random sample is taken as example. - The international and regional claim of environmental pedagogics is structured by UNESCO-documents.

  19. Syntegra - the next generation of powered bogies; Syntegra - Innovativer Prototyp einer naechsten Triebfahrwerk-Generation

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, T.; Teichmann, M. [Siemens AG, Graz (Austria); Joeckel, A. [Siemens AG, Graz (Austria); Loewenstein, L.; Wangelin, F. von [Siemens AG, Erlangen (Germany)

    2007-07-01

    The innovative Syntegra {sup registered} concept fundamentally revolutionizes the characteristics of today's powered bogies and represents a new and highly integrative approach in bogie design. Syntegra combines the traction, bogie and braking technology to form a unified mechatronic system. This approach and, above all, the change of technology generate a large number of synergetic benefits. This new generation of powered bogies unites high efficiency and low weight with reduced lifecycle costs (LCC) and offers considerably better performance than conventional bogie solutions. A first prototype is in service. (orig.)

  20. Background information on a multimedia nitrogen emission reduction strategy; Hintergrundpapier zu einer multimedialen Stickstoffemissionsminderungsstrategie

    Energy Technology Data Exchange (ETDEWEB)

    Geupel; Jering; Frey (and others)

    2009-04-15

    The background information report on a multimedia nitrogen reduction strategy covers the following chapters: 1. Introduction: the nitrogen cascade and the anthropogenic influence, environmental impact of increased nitrogen emissions and effects on human health. 2. Sources and balancing of anthropogenic nitrogen emissions in Germany. 3. Environmental quality targets, activity goals of environmental measures and instruments of an integrated nitrogen reduction strategy. 4. Conclusions and perspectives. The attachments include emission sources, nitrogen release and nitrogen transport in Germany; catalogue of measures and instruments according the criteria efficiency and cost-efficacy.

  1. Mid-Term Results of Surgical Treatment of Atrial Fibrillation in Valvular Heart Disease Assesed by Speckle Tracking Echocardiography.

    Science.gov (United States)

    Lorenzo, Natalia; Mendez, Irene; Taibo, Mikel; Martinis, Gianfranco; Badia, Sara; Reyes, Guillermo; Aguilar, Rio

    2018-03-19

    Atrial fibrillation frequently affects patients with valvular heart disease. Ablation of atrial fibrillation during valvular surgery is an alternative for restoring sinus rhythm. This study aimed to evaluate mid-term results of successful atrial fibrillation surgical ablation during valvular heart disease surgery, to explore left atrium post-ablation mechanics and to identify predictors of recurrence. Fifty-three consecutive candidates were included. Eligibility criteria for ablation included persistent atrial fibrillation valvular heart disease surgery.

  2. Effects of iodine and thyroid hormones in inducing and treating Hashimoto's thyroiditis; Effekte von Iodid und Schilddruesenhormonen bei der Induktion und Therapie einer Thyreoiditis Hashimoto

    Energy Technology Data Exchange (ETDEWEB)

    Rink, T.; Schroth, H.J.; Holle, L.H.; Garth, H. [Stadtkrankenhaus Hanau (Germany). Abt. fuer Nuklearmedizin

    1999-07-01

    Aim: The effect of an iodine prophylaxis on the induction of Hashimoto's thyroiditis as well as the influence of various therapeutic approaches on the course of antithyroglobulin (TgAb) and antiperoxidase (TPOAb) antibodies in manifest diseases are evaluated. Method: A collective of 375 euthyroid subjects without relevant goiter received daily doses of 200 micrograms iodide, weekly doses of 1.53 milligrams iodide, or no medication. A second group of 377 patients suffering from Hashimoto's thyroiditis was treated with a non-suppressive hormone medication, a suppressive hormone administration, a combination of a non-suppressive hormone therapy with low dose iodide (50-150 micrograms/day), mere iodide in doses of 200 micrograms/day, or received no therapy. The mean observation period in these two groups was 860 and 848 days, respectively. Results: There was no significant increase of the antibody levels in the subgroup with 200 micrograms iodide/day and in the non-treated subjects of the first collective. However, the group that received 1.53 milligrams iodide/week presented a distinct increase of the TgAb as well as the TPOAb, and the incidence of Hashimoto's thyroiditis was 4-fold higher than in the two other subgroups. The patients of the second collective revealed a sinificant decrease of the TgAb in the subgroups treated with up to 200 micrograms iodide/day, while the reduction of the TPOAb depended on the thyrotropin level and was most significant in the suppressed group (p<0.0001). Conclusion: To lower the incidence of autoimmune thyroid diseases in predisposed subjects, a daily iodine supplementation seems to be superior to high-dose weekly administrations. A hormone therapy combined with a daily, low-dose iodine medication is able to reduce the TgAb and the TPOAb levels even in patients with Hashimoto's thyroidits. (orig.) [German] Ziel: Untersucht wurden der Einfluss einer Iodprophylaxe auf die Inzidenz einer Autoimmunthyreoiditis bzw

  3. Role of radiotherapy in age-related macular degeneration. A prospective study; Photonentherapie der subfovealen choroidalen Neovaskularisation bei altersabhaengiger Makuladegeneration. Ergebnisse einer prospektiven Studie an 40 Patienten

    Energy Technology Data Exchange (ETDEWEB)

    Prettenhofer, U.; Mayer, R.; Oechs, A.; Pakisch, B.; Stranzl, H.; Willfurth, P.; Hackl, A. [Univ. Graz (Austria). Abt. fuer Strahlentherapie; Haas, A. [Univ. Graz (Austria). Universitaets-Augenklinik

    1998-12-01

    Methoden: Zwischen September 1995 und Juli 1996 wurden 40 Patienten (neun Maenner, 31 Frauen; mittleres Alter 74 Jahre; 61 bis 83 Jahre) im Rahmen einer prospektiven Studie an unserer Abteilung bestrahlt. Acht Patienten hatten die klassische Form, 32 die okkulte Form der Makuladegeneration. Vor der Behandlung sowie ein, drei, sechs und zwoelf Monate nach der Bestrahlung wurden ein kompletter ophthalmologischer Status mit Visus- und Gesichtsfeldbestimmung sowie eine Fluoreszein- und Indozyaningruen-Angiographie durchgefuehrt. Die Bestrahlung erfolgte generell von einem 5,5x4,5 cm grossen lateralen, nicht gekippten Feld in Half-beam-Block-Technik mit 8-MV-Photonen mit einer Einzeldosis von 1,8 Gy bis zu einer Gesamtdosis von 14,4 Gy. Ergebnisse: Bestrahlungsspezifische Nebenwirkungen wurden weder waehrend der Bestrahlung noch in der Nachsorgephase beobachtet. Sechs Monate nach Bestrahlung kam es bei zwei Patienten (5%) zu einer Visusverbesserung, bei 17 (42,5%) Patienten zu einer Stabilisierung und bei 21 (52,5%) Patienten zu einer Verschlechterung. Nach einem Jahr hatte sich bei sechs (15%) Patienten der Visus stabilisiert, bei 34 (85%) Patienten verschlechterte sich die Sehkraft vergleichbar dem Spontanverlauf. Die mittlere Empfindlichkeit des zentralen Gesichtsfeldes verringerte sich von 16,5 auf 12,4 Dezibel (dB). Das Ausmass der Neovaskularisationen, Exsudationen und Membranbildungen nahm bei beiden Formen um ein Fuenf-, bis Siebenfaches zu. Subjektiv hatte sich nach zwoelf Monaten das Sehvermoegen bei drei (7,5%) Patienten verbessert, bei zwoelf (30%) Patienten stabilisiert und bei 25 (62,5%) Patienten verschlechtert. Schlussfolgerung: Mit einer Gesamtdosis von 14,4 Gy konnte nach zwoelf Monaten kein befriedigender Einfluss auf den Spontanverlauf der Erkankung beobachtet werden. Ehe definitive Rueckschluesse gezogen werden koennen, sollten die Ergebnisse bereits laufender bzw. abgeschlossener Multicenterstudien abgewartet werden. (orig.)

  4. Assembly of α-synuclein fibrils in nanoscale studied by peptide truncation and AFM

    International Nuclear Information System (INIS)

    Zhang Feng; Lin Xiaojing; Ji Lina; Du Haining; Tang Lin; He Jianhua; Hu Jun; Hu Hongyu

    2008-01-01

    α-Synuclein (α-Syn) fibrils are the major component of Lewy bodies that are closely associated with the pathogenesis of Parkinson's disease, but the mechanism for the fibril assembly remains poorly understood. Here we report using a combination of peptide truncation and atomic force microscopy (AFM) to elucidate the self-assembly and morphology of the α-Syn fibrils. The results show that protease K significantly slims the fibrils from the mean height of ∼6.6 to ∼4.7 nm, whereas chaotropic denaturant urea completely breaks down the fibrils into small particles. The in situ enzymatic digestion also results in thinning of the fibrils, giving rise to some nicks on the fibrils. Moreover, N- or C-terminally truncated α-Syn fragments assemble into thinner filaments with the heights depending on the peptide lengths. A nine-residue peptide corresponding to the homologous GAV-motif sequence can form very thin (∼2.2 nm) but long (>1 μm) filaments. Thus, the central sequence of α-Syn forms a fibrillar core by cross-β-structure that is flanked by two flexible termini, and the orientation of the fibril growth is perpendicular to the β-sheet structures

  5. Use of Vitamins K antagonists in non-valvular atrial fibrillation ...

    African Journals Online (AJOL)

    Introduction: atrial fibrillation is the commonest cardiac rythm disorder. Thromboembolic accidents are common complications that should be prevented by anticoagulant treatment. The aim of our study is to assess the use of vitamins K antagonists in the prevention of thromboembolic risk in atrial fibrillation. Methods: it was a ...

  6. Mechanistic study of the inhibitory activity of Geum urbanum extract against α-Synuclein fibrillation

    DEFF Research Database (Denmark)

    Lobbens, Eva Stephanie; Breydo, Leonid; Pedersen, Thomas Skamris

    2016-01-01

    microscopy. Since the extract is a complex mixture, structure-function relationships could not be determined. Under the experimental conditions investigated, Geum urbanum was found to inhibit α-Synuclein fibrillation in a concentration dependent way, and to partly disintegrate preformed α-Synuclein fibrils...

  7. The changing face of glucagon fibrillation: Structural polymorphism and conformational imprinting

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Dikov, D.; Flink, J.L.

    2006-01-01

    concentration) appear less thermostable than those formed under more challenging conditions (high temperatures, low glucagon or low salt concentrations). Properties of preformed fibrils used for seeding are inherited in a prion-like manner. Thus, we conclude that the structure of fibrils formed by glucagon...

  8. Mouse senile amyloid fibrils deposited in skeletal muscle exhibit amyloidosis-enhancing activity.

    Directory of Open Access Journals (Sweden)

    Jinze Qian

    2010-05-01

    Full Text Available Amyloidosis describes a group of protein folding diseases in which amyloid proteins are abnormally deposited in organs and/or tissues as fine fibrils. Mouse senile amyloidosis is a disorder in which apolipoprotein A-II (apoA-II deposits as amyloid fibrils (AApoAII and can be transmitted from one animal to another both by the feces and milk excreted by mice with amyloidosis. Thus, mouse AApoAII amyloidosis has been demonstrated to be a "transmissible disease". In this study, to further characterize the transmissibility of amyloidosis, AApoAII amyloid fibrils were injected into transgenic Apoa2(cTg(+/- and normal R1.P1-Apoa2(c mice to induce AApoAII systemic amyloidosis. Two months later, AApoAII amyloid deposits were found in the skeletal muscles of amyloid-affected mice, primarily in the blood vessels and in the interstitial tissues surrounding muscle fibers. When amyloid fibrils extracted from the skeletal muscles were subjected to Western blot analysis, apoA-II was detected. Amyloid fibril fractions isolated from the muscles not only demonstrated the structure of amyloid fibrils but could also induce amyloidosis in young mice depending on its fibril conformation. These findings present a possible pathogenesis of amyloidosis: transmission of amyloid fibril conformation through muscle, and shed new light on the etiology involved in amyloid disorders.

  9. Alcohol consumption and risk of atrial fibrillation in men and women: the Copenhagen City Heart Study

    DEFF Research Database (Denmark)

    Mukamal, Kenneth J; Tolstrup, Janne S; Friberg, Jens

    2005-01-01

    and incident atrial fibrillation among 16,415 women and men enrolled in the Copenhagen City Heart Study. We ascertained use of beer, wine, and spirits individually at up to 3 study visits with a structured questionnaire. We identified cases of atrial fibrillation by routine study ECGs and a validated...

  10. Identification of a Common Binding Mode for Imaging Agents to Amyloid Fibrils from Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Skeby, Katrine Kirkeby; Sørensen, Jesper; Schiøtt, Birgit

    2013-01-01

    experimentally due to the insoluble nature of amyloid fibrils. This study uses molecular dynamics simulations to investigate the interactions between 13 aromatic amyloid imaging agents, entailing 4 different organic scaffolds, and a model of an amyloid fibril. Clustering analysis combined with free energy...

  11. Prednisone prevents atrial fibrillation promotion by atrial tachycardia remodeling in dogs

    NARCIS (Netherlands)

    Shiroshita-Takeshita, A; Brundel, BJJM; Lavoie, J; Nattel, S

    2006-01-01

    Background: There is evidence suggesting involvement of oxidative stress, inflammation, and calcineurin/nuclear factor of activated T cell pathways in atrial fibrillation. This study evaluated the efficacy of anti-inflammatory and calcineurin-inhibitory drugs on promotion of atrial fibrillation by

  12. Amyloid Fibril-Induced Structural and Spectral Modifications in the Thioflavin-T Optical Probe

    DEFF Research Database (Denmark)

    Murugan, N. Arul; Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob

    2013-01-01

    Motivated by future possibilities to design target molecules for fibrils with diagnostic or therapeutic capability related to amyloidosis diseases, we investigate in this work the dielectric nature of amyloid fibril microenvironments in different binding sites using an optical probe, thioflavin-T...

  13. Influence of Aluminium and EGCG on Fibrillation and Aggregation of Human Islet Amyloid Polypeptide

    Directory of Open Access Journals (Sweden)

    Zhi-Xue Xu

    2016-01-01

    Full Text Available The abnormal fibrillation of human islet amyloid polypeptide (hIAPP has been implicated in the development of type II diabetes. Aluminum is known to trigger the structural transformation of many amyloid proteins and induce the formation of toxic aggregate species. The (−-epigallocatechin gallate (EGCG is considered capable of binding both metal ions and amyloid proteins with inhibitory effect on the fibrillation of amyloid proteins. However, the effect of Al(III/EGCG complex on hIAPP fibrillation is unclear. In the present work, we sought to view insight into the structures and properties of Al(III and EGCG complex by using spectroscopic experiments and quantum chemical calculations and also investigated the influence of Al(III and EGCG on hIAPP fibrillation and aggregation as well as their combined interference on this process. Our studies demonstrated that Al(III could promote fibrillation and aggregation of hIAPP, while EGCG could inhibit the fibrillation of hIAPP and lead to the formation of hIAPP amorphous aggregates instead of the ordered fibrils. Furthermore, we proved that the Al(III/EGCG complex in molar ratio of 1 : 1 as Al(EGCG(H2O2 could inhibit the hIAPP fibrillation more effectively than EGCG alone. The results provide the invaluable reference for the new drug development to treat type II diabetes.

  14. Risk of atrial fibrillation among bisphosphonate users: a multicenter, population-based, Italian study

    NARCIS (Netherlands)

    L. Herrera (Lizbeth); I. Leal (Ingrid); F. Lapi (Francesco); M.J. Schuemie (Martijn); V. Arcoraci (Vincenzo); F. Cipriani (Francesco); E. Sessa (E.); A. Vaccheri (Alberto); C. Piccinni (C.); T. Staniscia (Tommaso); A. Vestri (Annarita); M. Di Bari (M.); G. Corrao (Giovanni); A. Zambon (A.); D Gregori (Dario); F. Carle (F.); M.C.J.M. Sturkenboom (Miriam); G. Mazzaglia (Giampiero); G. Trifirò (Gianluca)

    2015-01-01

    textabstractSummary: Bisphosphonate treatment is used to prevent bone fractures. A controversial association of bisphosphonate use and risk of atrial fibrillation has been reported. In our study, current alendronate users were associated with a higher risk of atrial fibrillation as compared with

  15. Apixaban in patients at risk of stroke undergoing atrial fibrillation ablation

    DEFF Research Database (Denmark)

    Kirchhof, Paulus; Haeusler, Karl Georg; Blank, Benjamin

    2018-01-01

    Aims: It is recommended to perform atrial fibrillation ablation with continuous anticoagulation. Continuous apixaban has not been tested. Methods and results: We compared continuous apixaban (5 mg b.i.d.) to vitamin K antagonists (VKA, international normalized ratio 2-3) in atrial fibrillation pa...

  16. Time to implement fitness and reduction of fatness in atrial fibrillation therapy

    NARCIS (Netherlands)

    Van Gelder, Isabelle C.; Hobbelt, Anne H.; Brugemann, Johan; Rienstra, Michiel

    This editorial refers to ‘Self-reported physical activity and major adverse events in patients with atrial fibrillation: a report from the EURObservational Research Programme Pilot Survey on Atrial Fibrillation (EORP-AF) General Registry’ by M. Proietti et al. , doi:10.1093/europace/euw150. Atrial

  17. Warfarin for the prevention of systemic embolism in patients with non-valvular atrial fibrillation

    DEFF Research Database (Denmark)

    Andersen, L V; Vestergaard, P; Deichgraeber, P

    2008-01-01

    Warfarin for stroke prevention in patients with atrial fibrillation (AF) is well documented. However, it has not been examined in the prevention of systemic embolism.......Warfarin for stroke prevention in patients with atrial fibrillation (AF) is well documented. However, it has not been examined in the prevention of systemic embolism....

  18. Heat-induced whey protein isolate fibrils: Conversion, hydrolysis, and disulphide bond formation

    NARCIS (Netherlands)

    Bolder, S.G.; Vasbinder, A.; Sagis, L.M.C.; Linden, van der E.

    2007-01-01

    Fibril formation of individual pure whey proteins and whey protein isolate (WPI) was studied. The heat-induced conversion of WPI monomers into fibrils at pH 2 and low ionic strength increased with heating time and protein concentration. Previous studies, using a precipitation method, size-exclusion

  19. J-shaped association between QTc interval duration and the risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Nielsen, Jonas Bille; Graff, Claus; Pietersen, Adrian

    2013-01-01

    The aim of this study was to investigate whether the heart rate-corrected QT (QTc) interval on the electrocardiogram (ECG) is associated with the onset of atrial fibrillation (AF).......The aim of this study was to investigate whether the heart rate-corrected QT (QTc) interval on the electrocardiogram (ECG) is associated with the onset of atrial fibrillation (AF)....

  20. Lessons from comparative studies of atrial fibrillation in dog, man and horse

    NARCIS (Netherlands)

    Meijler, F.L.; Tweel, I. van der; Herbschleb, J.N.; Heethaar, R.M.; Borst, C.

    1985-01-01

    Since its first description in 1903 by Hering, the irregularity of the heart beat has been the most striking characteristic of atrial fibrillation and has been subject of many studies. To quote Selzer, "Atrial fibrillation is the grandfather of cardiac arrhythmias." It is an arrhythmia that 1)

  1. Systolic and Diastolic Function by Tissue Doppler Imaging Predicts Mortality in Patients with Atrial Fibrillation

    DEFF Research Database (Denmark)

    Dons, Maria; BieringSørensen, Tor; Jensen, Jan Skov

    2015-01-01

    AIM: Tissue Doppler Imaging (TDI) detects early signs of left ventricular dysfunction. The prognostic potential of TDI in patients with atrial fibrillation (AF) has, however, not yet been clarified. This study evaluates the prognostic value of TDI in patients with atrial fibrillation. METHODS...

  2. Cardiovascular exercise and burden of arrhythmia in patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Skielboe, Ane Katrine; Bandholm, Thomas Quaade; Hakmann, Stine

    2017-01-01

    BACKGROUND: Physical activity at moderate-high intensity is recommended to prevent lifestyle diseases. Patients with atrial fibrillation are at risk of a sedentary lifestyle due to fear of exercise-induced episodes of atrial fibrillation. The burden of arrhythmia can be reduced by physical exercise...

  3. The spectrum of thyroid disease and risk of new onset atrial fibrillation

    DEFF Research Database (Denmark)

    Selmer, Christian; Olesen, Jonas Bjerring; Hansen, Morten Lock

    2012-01-01

    To examine the risk of atrial fibrillation in relation to the whole spectrum of thyroid function in a large cohort of patients.......To examine the risk of atrial fibrillation in relation to the whole spectrum of thyroid function in a large cohort of patients....

  4. Essential Oils May Lead α-Synuclein towards Toxic Fibrils Formation

    Directory of Open Access Journals (Sweden)

    Dina Morshedi

    2016-01-01

    Full Text Available α-Synuclein (α-Syn fibrillation links with Parkinson’s disease (PD and several related syndromes. It is believed that exposure to the factors which promote fibrillation may induce and progress such neurodegenerative diseases (NDs. Herein, the effects of some wildly used essential oils including Myrtus communis (M. communis on α-Syn fibrillation were examined. M. communis particularly increased α-Syn fibrillation in a concentration dependent manner. Given that applications of M. communis are very extensive in Asian societies, especially Zoroastrians, this study was extended towards its role on α-Syn fibrillation/cytotoxicity. By using a unilamellar vesicle, it was shown that the aggregated species with tendency to perturb membrane were increased in the presence of M. communis. In this regard, the cytotoxicity of α-Syn on SH-SH5Y cells was also increased significantly. Inappropriately, the effects of fibrillation inhibitors, baicalein and cuminaldehyde, were modulated in the presence of M. communis. However, major components of M. communis did not induce fibrillation and also the effect of M. communis was limited on other fibrinogenic proteins. Assuming that essential oils have the ability to pass through the blood brain barrier (BBB along with the popular attention on aromatherapy for the incurable ND, these findings suggest an implementation of fibrillation tests for essential oils.

  5. Insulin fibrillation: The influence and coordination of Zn2+

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Sønderby, Pernille; Bang, Maria Blanner

    2017-01-01

    fibrils has been debated for some years. We have therefore investigated the influence and binding geometry of zinc in fibrillated insulin using extended X-ray absorption fine-structure and X-ray absorption near-edge structure spectroscopy. The results were validated with fibre diffraction, Transmission...

  6. Double-stranded DNA Stimulates the Fibrillation of alpha-Synuclein in vitro and is Associated with the Mature Fibrils: An Electron Microscopy Study

    NARCIS (Netherlands)

    Cherny, Dmitry; Hoyer, Wolfgang; Subramaniam, Vinod; Jovin, Thomas M.

    2004-01-01

    Filamentous aggregates formed by α-synuclein are a prominent and presumably key etiological factor in Parkinson's and other neurodegenerative diseases characterized by motor disorders. Numerous studies have demonstrated that various environmental and intracellular factors affect the fibrillation

  7. Psoriasis is associated with subsequent atrial fibrillation in hypertensive patients with left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Bang, Casper N; Okin, Peter M; Køber, Lars

    2014-01-01

    BACKGROUND: Inflammation contributes to the pathogenesis of psoriasis as well as atrial fibrillation. The impact of psoriasis and its association with new-onset atrial fibrillation was assessed in hypertensive patients with left ventricular hypertrophy (LVH). METHODS: The predictive value...... or developed psoriasis and new-onset atrial fibrillation occurred in 506 patients (7.1%) during a mean follow-up of 4.7 ± 1.1 years. At baseline, the psoriasis patients were younger (65 ± 7 vs. 67 ± 7 years) and had less left ventricle hypertrophy by ECG Sokolow-Lyon voltage (27.6 ± 9.7 vs. 30.1 ± 10.4 mm...... of baseline or incident psoriasis for new-onset atrial fibrillation was evaluated in 7099 hypertensive patients with electrocardiographic LVH with no history of atrial fibrillation or other cardiovascular disease, in sinus rhythm on their baseline electrocardiogram. RESULTS: A total of 154 patients (2.2%) had...

  8. Direct visualization of HIV-enhancing endogenous amyloid fibrils in human semen

    Science.gov (United States)

    Usmani, Shariq M.; Zirafi, Onofrio; Müller, Janis; Sandi-Monroy, Nathallie; Yadav, Jay K.; Meier, Christoph; Weil, Tanja; Roan, Nadia R.; Greene, Warner C.; Walther, Paul; Nilsson, K. Peter R.; Hammarström, Per; Wetzel, Ronald; Pilcher, Christopher D.; Gagsteiger, Friedrich; Fändrich, Marcus; Kirchhoff, Frank; Münch, Jan

    2014-01-01

    Naturally occurring fragments of the abundant semen proteins prostatic acid phosphatase (PAP) and semenogelins form amyloid fibrils in vitro. These fibrils boost HIV infection and may play a key role in the spread of the AIDS pandemic. However, the presence of amyloid fibrils in semen remained to be demonstrated. Here, we use state of the art confocal and electron microscopy techniques for direct imaging of amyloid fibrils in human ejaculates. We detect amyloid aggregates in all semen samples and find that they partially consist of PAP fragments, interact with HIV particles and increase viral infectivity. Our results establish semen as a body fluid that naturally contains amyloid fibrils that are exploited by HIV to promote its sexual transmission. PMID:24691351

  9. NONPOTENTIALITY OF CHROMOSPHERIC FIBRILS IN NOAA ACTIVE REGIONS 11092 AND 9661

    International Nuclear Information System (INIS)

    Jing Ju; Yuan Yuan; Xu Yan; Wang Haimin; Reardon, Kevin; Wiegelmann, Thomas

    2011-01-01

    In this paper, we present a method to automatically segment chromospheric fibrils from Hα observations and further identify their orientation. We assume that chromospheric fibrils are aligned with the magnetic field. By comparing the orientation of the fibrils with the azimuth of the embedding chromospheric magnetic field extrapolated from a potential field model, the shear angle, a measure of nonpotentiality, along the fibrils is readily deduced. Following this approach, we make a quantitative assessment of the nonpotentiality of fibrils in two NOAA active regions (ARs): (1) the relatively simple AR 11092, observed with very high resolution by Interferometric Bidimensional Spectrometer, and (2) a β-γ-δ AR 9661, observed with median resolution by Big Bear Solar Observatory before and after an X1.6 flare.

  10. Polymorphism, metastable species and interconversion: the many states of glucagon fibrils

    DEFF Research Database (Denmark)

    Ghodke, Shirin D; Jensen, Grethe Vestergaard; Svane, Anna Sigrid P.

    2014-01-01

    physicochemical conditions such as high temperature, pressure, mechanical and chemical stress. Factors such as peptide concentration, accessible surface area, surface hydration of the glucagon molecular state, contact surface, temperature and ionic strength all contribute to fibrillar structure and stability...... fibril upon incubation at elevated temperatures (but not vice versa), indicating that fibrils are fundamentally malleable if they have not attained the most stable fibrillar state. While the effect of pressure on glucagon is complex (accelerating fibrillation at intermediate pressures and decelerating...... it at higher pressures), the thermal expansion coefficients obtained from these studies agree well with our previous calorimetric studies to reveal reduced or increased hydration of fibrils (leading to reduced or increased stability) depending on fibrillation conditions. Finally, we report...

  11. Conjugated Quantum Dots Inhibit the Amyloid β (1–42 Fibrillation Process

    Directory of Open Access Journals (Sweden)

    Garima Thakur

    2011-01-01

    Full Text Available Nanoparticles have enormous potential in diagnostic and therapeutic studies. We have demonstrated that the amyloid beta mixed with and conjugated to dihydrolipoic acid- (DHLA capped CdSe/ZnS quantum dots (QDs of size approximately 2.5 nm can be used to reduce the fibrillation process. Transmission electron microscopy (TEM and atomic force microscopy (AFM were used as tools for analysis of fibrillation. There is a significant change in morphology of fibrils when amyloid β (1–42 (Aβ (1–42 is mixed or conjugated to the QDs. The length and the width of the fibrils vary under modified conditions. Thioflavin T (ThT fluorescence supports the decrease in fibril formation in presence of DHLA-capped QDs.

  12. Angiotensinogen and ACE gene polymorphisms and risk of atrial fibrillation in the general population

    DEFF Research Database (Denmark)

    Ravn, Lasse S; Benn, Marianne; Nordestgaard, Børge G

    2008-01-01

    OBJECTIVES: The renin-angiotensin system may play a role in the pathogenesis of atrial fibrillation, and renin-angiotensin system blockers reduce the risk of atrial fibrillation. We hypothesized that polymorphisms in the angiotensinogen and angiotensin-converting enzyme (ACE) genes encoding...... in the ACE gene; rare allele frequencies were 0.16, 0.40, 0.12, 0.41, and 0.49, respectively. Participants had sinus rhythm at inclusion. During 26 years of follow-up, 968 individuals developed atrial fibrillation. Multifactorially adjusted hazard ratios for atrial fibrillation for a-20c ac and cc versus aa...... proteins in this system predict risk of atrial fibrillation. METHODS AND RESULTS: We genotyped 9235 individuals from the Danish general population, The Copenhagen City Heart Study, for the a-20c, g-6a, T174M, and M235T polymorphisms in the angiotensinogen gene and the insertion/deletion (I/D) polymorphism...

  13. Simultaneous measurement of amyloid fibril formation by dynamic light scattering and fluorescence reveals complex aggregation kinetics.

    Directory of Open Access Journals (Sweden)

    Aaron M Streets

    Full Text Available An apparatus that combines dynamic light scattering and Thioflavin T fluorescence detection is used to simultaneously probe fibril formation in polyglutamine peptides, the aggregating subunit associated with Huntington's disease, in vitro. Huntington's disease is a neurodegenerative disorder in a class of human pathologies that includes Alzheimer's and Parkinson's disease. These pathologies are all related by the propensity of their associated protein or polypeptide to form insoluble, β-sheet rich, amyloid fibrils. Despite the wide range of amino acid sequence in the aggregation prone polypeptides associated with these diseases, the resulting amyloids display strikingly similar physical structure, an observation which suggests a physical basis for amyloid fibril formation. Thioflavin T fluorescence reports β-sheet fibril content while dynamic light scattering measures particle size distributions. The combined techniques allow elucidation of complex aggregation kinetics and are used to reveal multiple stages of amyloid fibril formation.

  14. Probability of atrial fibrillation after ablation: Using a parametric nonlinear temporal decomposition mixed effects model.

    Science.gov (United States)

    Rajeswaran, Jeevanantham; Blackstone, Eugene H; Ehrlinger, John; Li, Liang; Ishwaran, Hemant; Parides, Michael K

    2018-01-01

    Atrial fibrillation is an arrhythmic disorder where the electrical signals of the heart become irregular. The probability of atrial fibrillation (binary response) is often time varying in a structured fashion, as is the influence of associated risk factors. A generalized nonlinear mixed effects model is presented to estimate the time-related probability of atrial fibrillation using a temporal decomposition approach to reveal the pattern of the probability of atrial fibrillation and their determinants. This methodology generalizes to patient-specific analysis of longitudinal binary data with possibly time-varying effects of covariates and with different patient-specific random effects influencing different temporal phases. The motivation and application of this model is illustrated using longitudinally measured atrial fibrillation data obtained through weekly trans-telephonic monitoring from an NIH sponsored clinical trial being conducted by the Cardiothoracic Surgery Clinical Trials Network.

  15. Picosecond dissociation of amyloid fibrils with infrared laser: A nonequilibrium simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Hoang Viet, Man; Roland, Christopher, E-mail: cmroland@ncsu.edu; Sagui, Celeste, E-mail: sagui@ncsu.edu [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202 (United States); Derreumaux, Philippe; Nguyen, Phuong H., E-mail: phuong.nguyen@ibpc.fr [Laboratoire de Biochimie Théorique, UPR 9080, CNRS Université Denis Diderot, Sorbonne Paris Cité IBPC, 13 rue Pierre et Marie Curie, 75005 Paris (France); Li, Mai Suan [Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City (Viet Nam)

    2015-10-21

    Recently, mid-infrared free-electron laser technology has been developed to dissociate amyloid fibrils. Here, we present a theoretical framework for this type of experiment based on laser-induced nonequilibrium all-atom molecular dynamics simulations. We show that the fibril is destroyed due to the strong resonance between its amide I vibrational modes and the laser field. The effects of laser irradiation are determined by a balance between fibril formation and dissociation. While the overall rearrangements of the fibril finish over short time scales, the interaction between the peptides and the solvent continues over much longer times indicating that the waters play an important role in the dissociation process. Our results thus provide new insights into amyloid fibril dissociation by laser techniques and open up new venues to investigate the complex phenomena associated with amyloidogenesis.

  16. Intracellular Calcium Dynamics and Autonomic Stimulation in Atrial Fibrillation: Mechanisms and Implications

    Directory of Open Access Journals (Sweden)

    Chung-Chuan Chou, MD

    2008-01-01

    Full Text Available While atrial fibrillation is characterized by the co-existence of multiple activation waves within the atria, rapid activations in the pulmonary veins play an important role for the initiation and maintenance of atrial fibrillation. In addition to reentry, non-reentrant mechanisms resulting from abnormal intracellular calcium handling and intracellular calcium overload can also be responsible for these rapid activations in the pulmonary veins. Meanwhile, alterations of autonomic tone, involving both the sympathetic and parasympathetic nervous system, have been implicated in initiating paroxysmal atrial fibrillation. But the effectiveness of autonomic modulation as an adjunctive therapeutic strategy to catheter ablation of atrial fibrillation has been inconsistent. The interactions between the autonomic nervous system and atrial fibrillation are more complex than currently understood and further mechanistic and clinical studies are warranted.

  17. Atrial Fibrillation and Coronary Bypass Surgery – What Can Be Risk Factors for its' Appearance?

    Directory of Open Access Journals (Sweden)

    Slavenka Štraus

    2010-02-01

    Full Text Available The main goal of our study was to evalúate possible perioperative risk factors for occurrence of atrial fibrillation in the postoperative period in patients after CABG operations. The study included 140 patients after CABG, divided into two groups - Group I - 64 patients with new onset of POAF and Group II - 76 patients without postoperative atrial fibrillation occurrence. In both groups possible risk factors for atrial fibrillation onset (preoperative and postoperative were analyzed.Results showed that we can predict new onset of atrial fibrillation after CABG if the following preoperative factors are present - low ejection fraction (less than 40%, LAd > 40mm, higher body mass index (BMI over 30, presence of COPD and older age. Important perioperative factors for onset of atrial fibrillation in our study were longer extracorporeal circulation, increased dose/number of inotropic drugs, blood transfusion and elevated WBC count postoperatively.

  18. Therapeutical considerations in associated atrial fibrillation and heart failure.

    Science.gov (United States)

    Mitu, O; Mitu, F; Constantin, S; Cojocaru, Elena; Leon, Maria-Magdalena

    2014-01-01

    Atrial fibrillation is a supraventricular tachyarrhythmia very common in medical practice, often associated with heart failure. Pathophysiological relationship between atrial fibrillation and heart failure is in the attention of numerous case studies, being incomplete elucidated. We made a retrospective study on patients with both diseases, hospitalized in Cardiovascular Rehabilitation Hospital, Iasi, during 01.01.2013 - 31.12.2013. The obtained data allowed the classification of patients according to gender distribution, age groups, area of origin, clinical aspects, and association with other diseases, instituted treatment and appreciation of CHADS2 score. Data interpretation was performed with appropriate statistical methods. We found a higher frequency of the disease among male patients, male: female ratio being 2:1; the most of the patients lived in urban area. The pick of diseases incidence was in patients over 65 years with a total percentage of 70.84% of cases. We noted that the most common symptoms were exertional dyspnea (in all patients), palpitations, dizziness, headache, fatigue, asthenia, dyspnea at rest and pain/chest pressure. In our study, the majority of patients received the beta-blocker--digoxin combination (46 patients, 40 patients respectively). The coexistence of the two disorders could be explained by identifying common risk factors. Beta blockers should be the first therapeutic option in patients with chronic heart failure and atrial fibrillation because they have the effect of controlling heart rate and improve survival in patients with these disorders. Meanwhile, digoxin is a drug, only certain conditions of high accuracy monitoring; whose major clinical indications are heart failure and atrial rhythm disturbances.

  19. A new therapeutic strategy for electrical cardioversion of atrial fibrillation.

    Science.gov (United States)

    de Luca, I; Sorino, M; Del Salvatore, B; de Luca, L

    2001-11-01

    The conventional approach to cardioversion of atrial fibrillation includes a period of anticoagulation with oral anticoagulant therapy (OAT) extending from 3 weeks precardioversion to 4 weeks postcardioversion. The protocol of rapid anticoagulation (such as that of the ACUTE study) consists of a precardioversion transesophageal echocardiography (TEE) followed by OAT for 4 weeks. In the last few years low-molecular-weight heparins have established themselves as a safe and efficacious alternative to traditional antithrombotic therapies. The aim of this study was to demonstrate that the exclusion of thrombi by precardioversion TEE together with the exclusion of atrial stunning by a second TEE performed after 1 week, to date not suggested in the literature, could reduce to 7 days the period of pericardioversion anticoagulation. This therapy would be carried out using low-molecular-weight heparins with no need for biological monitoring and with the possibility of self-administration. We have studied 57 consecutive patients who had atrial fibrillation or flutter with a history of atrial fibrillation lasting > 48 hours. All patients received enoxaparin at a dosage of 100 IU antiXa/kg twice daily before undergoing multiplane TEE. Previous informed consent and ethical committee authorization had been obtained. Twenty-four hours following TEE, in the absence of thrombi and/or spontaneous moderate/severe echocontrast in the atrial chambers, the patients underwent electrical cardioversion and were discharged within 24 hours of sinus rhythm restoration. These patients were prescribed enoxaparin at the indicated dosage twice daily until TEE, performed in an outpatients setting 7 days following cardioversion. In the absence of thrombi and/or atrial and/or left atrial appendage stunning, OAT was terminated. Enoxaparin was associated with OAT for the following 3 weeks if any of the following signs of stunning were present: A wave inferior to the normal value for age at transmitral

  20. The immediate future for the medical treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Pedersen, Ole Dyg; Brendorp, Bente; Køber, Lars

    2002-01-01

    ) the rhythm causes loss of atrioventricular synchrony, which reduces diastolic filling and may lead to heart failure; and iii) atrial contraction is lost leading to stagnant blood that again may lead to atrial thrombi and peripheral embolism. Thus, the treatment of atrial fibrillation is focused...... on the maintenance of sinus rhythm, rate control and prevention of embolism. For the maintenance of sinus rhythm, all drugs under current development are potassium channel blockers; the so-called class III anti-arrhythmic drugs. Those which have been further investigated appear to be valuable for maintenance...

  1. Entropy measurements in paroxysmal and persistent atrial fibrillation

    International Nuclear Information System (INIS)

    Cervigón, R; Moreno, J; Pérez-Villacastín, J; Reilly, R B; Millet, J; Castells, F

    2010-01-01

    Recent studies on atrial fibrillation (AF) have identified different activation patterns in paroxysmal and persistent AF. In this study, bipolar intra-atrial registers from 28 patients (14 paroxysmal AF and 14 persistent AF) were analyzed in order to find out regional differences in the organization in both types of arrhythmias. The organization of atrial electrical activity was assessed in terms of nonlinear parameters, such as entropy measurements. Results showed differences between the atrial chambers with a higher disorganization in the left atrium in paroxysmal AF patients and a more homogenous behavior along the atria in persistent AF patients

  2. Cardioversion for atrial fibrillation in current European practice

    DEFF Research Database (Denmark)

    Hernández-Madrid, Antonio; Svendsen, Jesper Hastrup; Lip, Gregory Y.H.

    2013-01-01

    This survey was conducted to provide an insight into the current clinical practice regarding the use of cardioversion for atrial fibrillation (AF) in Europe. Responses were received from 57 centres across Europe, 71.9% of which were university hospitals. For electrical cardioversion, general...... anaesthesia was managed by an anaesthesiologist in 73.9% of centres and by a cardiologist in 37%. In the majority of centres, electrical cardioversion was performed using a biphasic defibrillator (85.1%). Antiarrhythmic drugs were routinely prescribed prior to electrical cardioversion by 54.3% of hospitals...

  3. Plasma YKL-40, a new biomarker for atrial fibrillation?

    DEFF Research Database (Denmark)

    Henningsen, Kristoffer Mads; Therkelsen, Susette Krohn; Johansen, Julia Sidenius

    2009-01-01

    AIMS: The aim of this study was to determine changes in a new potential biomarker plasma YKL-40 in patients with atrial fibrillation (AF) before and after electrical cardioversion (CV). METHODS AND RESULTS: Plasma concentrations of YKL-40 were measured in 56 patients (mean age 65 years, range 34......-84) with persistent AF (lasting mean 128 days, range 14-960), in 19 age-matched patients with permanent AF, and in 19 healthy subjects. The patients with persistent AF underwent CV. Plasma YKL-40 was measured prior to CV, and at follow-up after 24 h, 30 and 180 days. Patients with persistent AF had lower plasma YKL...

  4. Mass Determination of Entire Amyloid Fibrils by Using Mass Spectrometry.

    Science.gov (United States)

    Doussineau, Tristan; Mathevon, Carole; Altamura, Lucie; Vendrely, Charlotte; Dugourd, Philippe; Forge, Vincent; Antoine, Rodolphe

    2016-02-12

    Amyloid fibrils are self-assembled protein structures with important roles in biology (either pathogenic or physiological), and are attracting increasing interest in nanotechnology. However, because of their high aspect ratio and the presence of some polymorphism, that is, the possibility to adopt various structures, their characterization is challenging and basic information such as their mass is unknown. Here we show that charge-detection mass spectrometry, recently developed for large self-assembled systems such as viruses, provides such information in a straightforward manner. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Exercise-Induced Ventricular Fibrillation: Seven Years Follow-Up

    Directory of Open Access Journals (Sweden)

    Gökmen Gemici

    2011-11-01

    Full Text Available We present a 7-year follow-up of a 55-year-old male who experienced ventricular fibrillation during the recovery period of exercise testing and refused implantation of an ICD. Normal left ventricular systolic function was found on echocardiographic examination, and coronary angiography revealed only a side branch disease with a vessel diameter of less than 2 millimeters. The patient was discharged on metoprolol and ASA in addition to his previous treatment with lisinopril and simvastatin. Outpatient cardiac evaluation by repeated 24-hour ECG monitorizations (Holter revealed normal findings. On follow up visits every six months for the past seven years, the patient was found to be asymptomatic.

  6. Atrial Fibrillation - A Common Ground for Neurology and Cardiology.

    Science.gov (United States)

    Abukhalil, Fawzi; Bodhit, Aakash; Cai, Peter Y; Ansari, Saeed; Thenkabail, Spandana; Ganji, Sarah; Saravanapavan, Pradeepan; Chandra Shekhar, Chandana; Waters, Michael F; Beaver, Thomas M; Shushrutha Hedna, Vishnumurthy

    2013-01-01

    Atrial fibrillation (AF) has a huge impact on clinical stroke because it is the primary cause of cardio-embolism, which constitutes ~20% of all strokes. As a result, there is a great need to explore safer and more effective primary and secondary prophylactic agents. In this article, we discuss the overlapping issues pertaining to AF from both a neurology and cardiology standpoint. We focus on the dynamic interplay of neurovascular and cardiovascular diseases in relation to AF, traditional and novel risk factors for AF leading to stroke, impact of AF on cognitive decline, and current upstream medical and surgical options for embolism prophylaxis.

  7. CT imaging of complications of catheter ablation for atrial fibrillation

    International Nuclear Information System (INIS)

    Shroff, G.S.; Guirguis, M.S.; Ferguson, E.C.; Oldham, S.A.A.; Kantharia, B.K.

    2014-01-01

    The complication rate following radiofrequency catheter ablation for atrial fibrillation is low (<5%). Complications include pericardial effusion, cardiac tamponade, pulmonary vein stenosis, oesophageal ulceration or perforation, atrio-oesophageal fistula formation, stroke/transient ischaemic attack, phrenic nerve injury, haematoma at the puncture site, and femoral arteriovenous fistula. Among available imaging tools, computed tomography (CT) can be very useful in diagnosing complications of the procedure, particularly in the subacute and delayed stages after ablation. This review illustrates CT imaging of several of the common and uncommon complications of radiofrequency catheter ablation

  8. Strain-induced internal fibrillation in looped aramid filaments

    DEFF Research Database (Denmark)

    Pauw, Brian Richard; Vigild, Martin Etchells; Mortensen, Kell

    2010-01-01

    in the scattering pattern is observed. One model capable of describing the intensity is a model of stacked cylinders. These cylinders could be part of the fibrillar structure present in the PPTA fibres, which consist of cylinder- to tape-like objects, the presence of which is supported by SEM images. One...... hypothetical physical interpretation presented here for the appearance of a regular internal structure is the occurrence of fibrillar separation in regions undergoing axially compressive strain, and the appearance of strain relief/slip planes between packs of fibrils in regions undergoing tensile strain...

  9. Fibril deformation under load of the rabbit Achilles tendon and medial collateral ligament femoral entheses.

    Science.gov (United States)

    Sevick, Johnathan L; Abusara, Ziad; Andrews, Stephen H; Xu, Minjia; Khurshid, Saad; Chatha, Jansher; Hart, David A; Shrive, Nigel G

    2018-04-10

    Microscopic visualization under load of the region connecting ligaments/tendons to bone, the enthesis, has been performed previously; however, specific investigation of individual fibril deformation may add insight to such studies. Detailed visualization of fibril deformation would inform on the mechanical strategies employed by this tissue in connecting two mechanically disparate materials. Clinically, an improved understanding of enthesis mechanics may help guide future restorative efforts for torn or injured ligaments/tendons, where the enthesis is often a point of weakness. In this study, a custom ligament/tendon enthesis loading device was designed and built, a unique method of sample preparation was devised, and second harmonic and two-photon fluorescence microscopy were used to capture the fibril-level load response of the rabbit Achilles tendon and medial collateral ligament femoral entheses. A focus was given to investigation of the mechanical problem of fibril embedment. Resultant images indicate a rapid (occurring over approximately 60 μm) change in fibril orientation at the interface of ligament/tendon and calcified fibrocartilage early in the loading regime, before becoming relatively constant. Such a change in fibril angle helps confirm the materially graded region demonstrated by others, while, in this case, providing additional insight into fibril bending. We speculate that the scale of the mechanical problem (i.e., fibril diameters being on the order of 250 nm) allows fibrils to bend over the small (relative to the imaging field of view, but large relative to fibril diameter) distances observed; thus, potentially lessening required embedment lengths. Nevertheless, this behavior merits further investigation to be confirmed. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  10. Surface characterization of insulin protofilaments and fibril polymorphs using tip-enhanced Raman spectroscopy (TERS).

    Science.gov (United States)

    Kurouski, Dmitry; Deckert-Gaudig, Tanja; Deckert, Volker; Lednev, Igor K

    2014-01-07

    Amyloid fibrils are β-sheet-rich protein aggregates that are strongly associated with a variety of neurodegenerative maladies, such as Alzheimer's and Parkinson's diseases. Even if the secondary structure of such fibrils is well characterized, a thorough understanding of their surface organization still remains elusive. Tip-enhanced Raman spectroscopy (TERS) is one of a few techniques that allow the direct characterization of the amino acid composition and the protein secondary structure of the amyloid fibril surface. Herein, we investigated the surfaces of two insulin fibril polymorphs with flat (flat) and left-twisted (twisted) morphology. It was found that the two differ substantially in both amino acid composition and protein secondary structure. For example, the amounts of Tyr, Pro, and His differ, as does the number of carboxyl groups on the respective surfaces, whereas the amounts of Phe and of positively charged amino and imino groups remain similar. In addition, the surface of protofilaments, the precursors of the mature flat and twisted fibrils, was investigated using TERS. The results show substantial differences with respect to the mature fibrils. A correlation of amino acid frequencies and protein secondary structures on the surface of protofilaments and on flat and twisted fibrils allowed us to propose a hypothetical mechanism for the propagation to specific fibril polymorphs. This knowledge can shed a light on the toxicity of amyloids and define the key factors responsible for fibril polymorphism. Finally, this work demonstrates the potential of TERS for the surface characterization of amyloid fibril polymorphs. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  11. Distribution state estimation based voltage control for distribution networks; Koordinierte Spannungsregelung anhand einer Zustandsschaetzung im Verteilnetz

    Energy Technology Data Exchange (ETDEWEB)

    Diwold, Konrad; Yan, Wei [Fraunhofer IWES, Kassel (Germany); Braun, Martin [Fraunhofer IWES, Kassel (Germany); Stuttgart Univ. (Germany). Inst. fuer Energieuebertragung und Hochspannungstechnik (IEH)

    2012-07-01

    The increased integration of distributed energy units creates challenges for the operators of distribution systems. This is due to the fact that distribution systems that were initially designed for distributed consumption and central generation now face decentralized feed-in. One imminent problem associated with decentralised fee-in are local voltage violations in the distribution system, which are hard to handle via conventional voltage control strategies. This article proposes a new voltage control framework for distribution system operation. The framework utilizes reactive power of distributed energy units as well on-load tap changers to mitigate voltage problems in the network. Using an optimization-band the control strategy can be used in situations where network information is derived from distribution state estimators and thus holds some error. The control capabilities in combination with a distribution state estimator are tested using data from a real rural distribution network. The results are very promising, as voltage control is achieved fast and accurate, preventing a majority of the voltage violations during system operation under realistic system conditions. (orig.)

  12. Dynamic behavior of small heat shock protein inhibition on amyloid fibrillization of a small peptide (SSTSAA) from RNase A

    International Nuclear Information System (INIS)

    Xi, Dong; Dong, Xiao; Deng, Wei; Lai, Luhua

    2011-01-01

    Highlights: ► Mechanism of small heat shock protein inhibition on fibril formation was studied. ► Peptide SSTSAA with modified ends was used for amyloid fibril formation. ► FRET signal was followed during the fibril formation. ► Mj HSP16.5 inhibits fibril formation when introduced in the lag phase. ► Mj HSP16.5 slows down fibril formation when introduced after the lag phase. -- Abstract: Small heat shock proteins, a class of molecular chaperones, are reported to inhibit amyloid fibril formation in vitro, while the mechanism of inhibition remains unknown. In the present study, we investigated the mechanism by which Mj HSP16.5 inhibits amyloid fibril formation of a small peptide (SSTSAA) from RNase A. A model peptide (dansyl-SSTSAA-W) was designed by introducing a pair of fluorescence resonance energy transfer (FRET) probes into the peptide, allowing for the monitoring of fibril formation by this experimental model. Mj HSP16.5 completely inhibited fibril formation of the model peptide at a molar ratio of 1:120. The dynamic process of fibril formation, revealed by FRET, circular dichroism, and electron microscopy, showed a lag phase of about 2 h followed by a fast growth period. The effect of Mj HSP16.5 on amyloid fibril formation was investigated by adding it into the incubation solution during different growth phases. Adding Mj HSP16.5 to the incubating peptide before or during the lag phase completely inhibited fibril formation. However, introducing Mj HSP16.5 after the lag phase only slowed down the fibril formation process by adhering to the already formed fibrils. These findings provide insight into the inhibitory roles of small heat shock proteins on amyloid fibril formation at the molecular level.

  13. Dynamic behavior of small heat shock protein inhibition on amyloid fibrillization of a small peptide (SSTSAA) from RNase A

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Dong [BNLMS, State Key Laboratory of Structural Chemistry for Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Center for Theoretical Biology, Peking University, Beijing 100871 (China); Dong, Xiao; Deng, Wei [BNLMS, State Key Laboratory of Structural Chemistry for Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Lai, Luhua, E-mail: lhlai@pku.edu.cn [BNLMS, State Key Laboratory of Structural Chemistry for Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Center for Theoretical Biology, Peking University, Beijing 100871 (China)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer Mechanism of small heat shock protein inhibition on fibril formation was studied. Black-Right-Pointing-Pointer Peptide SSTSAA with modified ends was used for amyloid fibril formation. Black-Right-Pointing-Pointer FRET signal was followed during the fibril formation. Black-Right-Pointing-Pointer Mj HSP16.5 inhibits fibril formation when introduced in the lag phase. Black-Right-Pointing-Pointer Mj HSP16.5 slows down fibril formation when introduced after the lag phase. -- Abstract: Small heat shock proteins, a class of molecular chaperones, are reported to inhibit amyloid fibril formation in vitro, while the mechanism of inhibition remains unknown. In the present study, we investigated the mechanism by which Mj HSP16.5 inhibits amyloid fibril formation of a small peptide (SSTSAA) from RNase A. A model peptide (dansyl-SSTSAA-W) was designed by introducing a pair of fluorescence resonance energy transfer (FRET) probes into the peptide, allowing for the monitoring of fibril formation by this experimental model. Mj HSP16.5 completely inhibited fibril formation of the model peptide at a molar ratio of 1:120. The dynamic process of fibril formation, revealed by FRET, circular dichroism, and electron microscopy, showed a lag phase of about 2 h followed by a fast growth period. The effect of Mj HSP16.5 on amyloid fibril formation was investigated by adding it into the incubation solution during different growth phases. Adding Mj HSP16.5 to the incubating peptide before or during the lag phase completely inhibited fibril formation. However, introducing Mj HSP16.5 after the lag phase only slowed down the fibril formation process by adhering to the already formed fibrils. These findings provide insight into the inhibitory roles of small heat shock proteins on amyloid fibril formation at the molecular level.

  14. European Society of Cardiology smartphone and tablet applications for patients with atrial fibrillation and their health care providers.

    Science.gov (United States)

    Kotecha, Dipak; Chua, Winnie W L; Fabritz, Larissa; Hendriks, Jeroen; Casadei, Barbara; Schotten, Ulrich; Vardas, Panos; Heidbuchel, Hein; Dean, Veronica; Kirchhof, Paulus

    2018-02-01

    We are in the midst of a digital revolution in health care, although the application of new and useful technology in routine clinical practice is variable. The Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly (CATCH ME) Consortium, in collaboration with the European Society of Cardiology (ESC), has funded the creation of two applications (apps) in atrial fibrillation (AF) for use in smartphones and tablets. The patient app aims to enhance patient education, improve communication between patients and health care professionals, and encourage active patient involvement in the management of their condition. The health care professional app is designed as an interactive management tool incorporating the new ESC Practice Guidelines on AF and supported by the European Heart Rhythm Association (EHRA), with the aim of improving best practice approaches for the care of patients with AF. Both stand-alone apps are now freely available for Android and iOS devices though the Google Play, Amazon, and Apple stores. In this article, we outline the rationale for the design and implementation of these apps. Our objective is to demonstrate the value of integrating novel digital technology into clinical practice, with the potential for patient engagement, optimization of pharmacological and interventional therapy in AF, and ultimately to improve patient outcomes. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Cardiology.

  15. European Society of Cardiology smartphone and tablet applications for patients with atrial fibrillation and their health care providers

    Science.gov (United States)

    Kotecha, Dipak; Chua, Winnie W L; Fabritz, Larissa; Hendriks, Jeroen; Casadei, Barbara; Schotten, Ulrich; Vardas, Panos; Heidbuchel, Hein; Dean, Veronica; Kirchhof, Paulus

    2018-01-01

    Abstract We are in the midst of a digital revolution in health care, although the application of new and useful technology in routine clinical practice is variable. The Characterizing Atrial fibrillation by Translating its Causes into Health Modifiers in the Elderly (CATCH ME) Consortium, in collaboration with the European Society of Cardiology (ESC), has funded the creation of two applications (apps) in atrial fibrillation (AF) for use in smartphones and tablets. The patient app aims to enhance patient education, improve communication between patients and health care professionals, and encourage active patient involvement in the management of their condition. The health care professional app is designed as an interactive management tool incorporating the new ESC Practice Guidelines on AF and supported by the European Heart Rhythm Association (EHRA), with the aim of improving best practice approaches for the care of patients with AF. Both stand-alone apps are now freely available for Android and iOS devices though the Google Play, Amazon, and Apple stores. In this article, we outline the rationale for the design and implementation of these apps. Our objective is to demonstrate the value of integrating novel digital technology into clinical practice, with the potential for patient engagement, optimization of pharmacological and interventional therapy in AF, and ultimately to improve patient outcomes. PMID:29040548

  16. Design and simulation of a control system for a run-off-river power plant; Entwurf und Simulation einer Staustufenregelung

    Energy Technology Data Exchange (ETDEWEB)

    Ott, C.

    2000-07-01

    In run-off-river plants with low discharge and under head-control, changes of inflow lead to amplified changes of outflow. In this thesis a frequency-domain-based design-procedure is introduced, which allows to add an inflow-dependent signal to the head-controller of conventional combined head- and flow-controllers. This efficiently minimizes the discharge amplification. The non-linearity of the channel-reach is taken into consideration by adapting the settings of the controller to the actual discharge. The development of a time-domain-based program system, taking into account all nonlinearities of a run-off-river-plant, is described. Using different test-functions, the capability of the improved combined head- and flow-control can be demonstrated. In both the time- and the frequency-domain it is shown, that the quality of control is not influenced to a significant extent by the inevitable inaccuracies in the description of the channel-reach and in the measurement of the actual inflow and outflow. (orig.) [German] Die Arbeit bietet eine Loesung fuer das Problem, dass im Niedrigwasserbereich wasserstandsgeregelter Staustufen Zuflussaenderungen durch die Staustufe verstaerkt an den Unterlieger weitergegeben werden. Als Problemloesung wird ein frequenzbereichsgestuetztes Entwurfsverfahren vorgestellt, mit dem die gebraeuchliche OW-Q-Regelung um eine zuflussabhaengige Aufschaltung auf den Pegelregler erweitert werden kann. Zusammen mit der Aufschaltung des Zuflusses auf den Abflussregler wird damit die Durchflussverstaerkung deutlich reduziert. Die Nichtlinearitaet der Regelstrecke 'Stauraum' wird durch eine Parameteradaption an den Staustufendurchfluss beruecksichtigt. Weiterhin wird die Entwicklung eines Programmsystems zur nichtlinearen Simulation einer Staustufenkette im Zeitbereich beschrieben. Damit kann anhand verschiedener Lastfaelle die Leistungsfaehigkeit der verbesserten OW-Q-Regelung nachgewiesen werden. Es wird im Zeit- und Frequenzbereich

  17. Zum Transfer kulturspezifischer Textbedeutungen. Theoretische und methodische Überlegungen aus einer semiotischen Perspektive

    Directory of Open Access Journals (Sweden)

    Hennecke, Angelika

    2009-01-01

    Full Text Available This paper discusses the role of cultural specific text elements in the constitution of the meaning of the text and focuses the problems which these elements can cause in the translation process. It is based on a description of the translation process as symbiosis of the three categories language, text and culture in a specific situation. The described comprehension of translation turns the question of the methodology of the cultural transfer into a key question that consequently has an impact on the praxis and didactics of translation. The meaning of a text is the result of a complex interaction of different systems in which different types of knowledge are activated. The central question is how culture manifests itself within texts and how these manifestations can be reconstructed, i.e. how the translator's decisions can be made transparent in the context of the transfer. Firstly there is a theoretical reflection on the interdependence of the three categories language, culture and text in which the underlying semiotic conception of text and culture is outlined. On this basis a pragma-semiotic model of the constitution of the text as a complex sign is presented, and a methodology for an integrative text analysis is deduced from this theoretical conception of text constitution. The different forms of cultural specific elements are analyzed and categorized, whereas in addition to the traditional manifestations the concept of intertextuality is introduced and discussed as an important fact for the pragmatic and cultural coherence of the text. The defined forms of cultural specific text elements are illustrated by a number of examples taken from translation praxis and classroom. All the examples are translations from Spanish into German. Finally, the practical and didactical implications, which are of great importance for the training of further translators, are discussed.

  18. A model of insulin fibrils derived from the x-ray crystal structure of a monomeric insulin (despentapeptide insulin).

    Science.gov (United States)

    Brange, J; Dodson, G G; Edwards, D J; Holden, P H; Whittingham, J L

    1997-04-01

    The crystal structure of despentapeptide insulin, a monomeric insulin, has been refined at 1.3 A spacing and subsequently used to predict and model the organization in the insulin fibril. The model makes use of the contacts in the densely packed despentapeptide insulin crystal, and takes into account other experimental evidence, including binding studies with Congo red. The dimensions of this model fibril correspond well with those measured experimentally, and the monomer-monomer contacts within the fibril are in accordance with the known physical chemistry of insulin fibrils. Using this model, it may be possible to predict mutations in insulin that might alleviate problems associated with fibril formation during insulin therapy.

  19. Modulation of human IAPP fibrillation: cosolutes, crowders and chaperones.

    Science.gov (United States)

    Gao, Mimi; Estel, Kathrin; Seeliger, Janine; Friedrich, Ralf P; Dogan, Susanne; Wanker, Erich E; Winter, Roland; Ebbinghaus, Simon

    2015-04-07

    The cellular environment determines the structure and function of proteins. Marginal changes of the environment can severely affect the energy landscape of protein folding. However, despite the important role of chaperones on protein folding, less is known about chaperonal modulation of protein aggregation and fibrillation considering different classes of chaperones. We find that the pharmacological chaperone O4, the chemical chaperone proline as well as the protein chaperone serum amyloid P component (SAP) are inhibitors of the type 2 diabetes mellitus-related aggregation process of islet amyloid polypeptide (IAPP). By applying biophysical methods such as thioflavin T fluorescence spectroscopy, fluorescence anisotropy, total reflection Fourier-transform infrared spectroscopy, circular dichroism spectroscopy and atomic force microscopy we analyse and compare their inhibition mechanism. We demonstrate that the fibrillation reaction of human IAPP is strongly inhibited by formation of globular, amorphous assemblies by both, the pharmacological and the protein chaperones. We studied the inhibition mechanism under cell-like conditions by using the artificial crowding agents Ficoll 70 and sucrose. Under such conditions the suppressive effect of proline was decreased, whereas the pharmacological chaperone remains active.

  20. Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

    International Nuclear Information System (INIS)

    Josefsson, Gabriella; Gamstedt, E. Kristofer; Ahvenainen, Patrik; Mushi, Ngesa Ezekiel

    2015-01-01

    The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils

  1. Automatic detection of atrial fibrillation in cardiac vibration signals.

    Science.gov (United States)

    Brueser, C; Diesel, J; Zink, M D H; Winter, S; Schauerte, P; Leonhardt, S

    2013-01-01

    We present a study on the feasibility of the automatic detection of atrial fibrillation (AF) from cardiac vibration signals (ballistocardiograms/BCGs) recorded by unobtrusive bedmounted sensors. The proposed system is intended as a screening and monitoring tool in home-healthcare applications and not as a replacement for ECG-based methods used in clinical environments. Based on BCG data recorded in a study with 10 AF patients, we evaluate and rank seven popular machine learning algorithms (naive Bayes, linear and quadratic discriminant analysis, support vector machines, random forests as well as bagged and boosted trees) for their performance in separating 30 s long BCG epochs into one of three classes: sinus rhythm, atrial fibrillation, and artifact. For each algorithm, feature subsets of a set of statistical time-frequency-domain and time-domain features were selected based on the mutual information between features and class labels as well as first- and second-order interactions among features. The classifiers were evaluated on a set of 856 epochs by means of 10-fold cross-validation. The best algorithm (random forests) achieved a Matthews correlation coefficient, mean sensitivity, and mean specificity of 0.921, 0.938, and 0.982, respectively.

  2. Biophysical aspects and novel treatments of atrial fibrillation.

    Science.gov (United States)

    Gigli, Lorenzo; Rosa, Gian M; Tagliasacchi, Maria I; Bonaventura, Aldo; Liberale, Luca; Montecucco, Fabrizio; Carbone, Federico; Bertero, Giovanni; Brunelli, Claudio

    2017-04-01

    Atrial fibrillation (AF) is a cardiac arrhythmia caused by various mechanisms, such as multiple re-entering wavelets, high frequency activity, and rotor sources. This narrative review was based on papers found on PubMed and MEDLINE up to May 2016. The search terms were "atrial fibrillation" in combination with "catheter ablation, pathophysiology, antiarrhythmic drugs". Antiarrhythmic drugs are the cornerstone of therapy in AF, but their efficacy and safety might have to be improved. In case of failure of pharmacologic therapies, other treatments can be considered. A better understanding of the important role of the pulmonary veins has led to new approaches, such as ablation procedures, which were initially only surgical, while percutaneous options were later added. However, these strategies may present various technical complications also when performed by skilled operators. A promising field of investigation is the genetics of AF, as highlighted by studies on the role of micro-RNA. Relevant improvement on the knowledge of the electrophysiological basis of genesis and maintenance of AF has been done in order to treat a very common arrhythmia, but further studies, as those in the genetics field, can open new challenging therapeutic horizons.

  3. Iodine replition, thyrotoxicosis and fibrillation in Isfahan, Iran

    International Nuclear Information System (INIS)

    Aminorroaya, Ashraf; Rohani, Sina; Sattari, Goshtasb; Haghighi, Sasan; Amini, Masoud

    2004-01-01

    Iodized salt was reintroduced in Iran in 1989. Just before distribution of iodized salt, thyrotoxicosis was observed in 3.7% of the patients with atrial fibrillation (AF) in university teaching hospitals in Isfahan, a centrally located city in Iran. As repletion of iodine may increase the rate of autoimmune thyroid diseases and toxic multinodular goiter, this study was designed to evaluate the rate of thyrotoxicosis in patients with AF in the same hospitals after about a decade of iodide salt consumption. In a case- control study with convenience sampling, 100 patients with AF and an equal number of age and sex matched subjects taking the same medications were selected as case and control groups, respectively in university hospitals in 1997. 8% of patients with atrial fibrillation had overt thyrotoxicosis versus one percent in the control group (odds ratio =8.6, 95% CI =6.5 to 10.7, p<0.02). Thyrotoxicosis in patients with AF was 8 times higher than in control group without AF. In comparison with the period before use of iodized salt, AF more than doubled (8%vs. 3.7%). Thyroid function should be evaluated in all patients older than 40 years of age with AF. The benefits of iodine supplementation are great, but more attention should be paid to the complications of iodine repletion, including thyrotoxicosis and its frequent accompaniment, AF. (author)

  4. What patients want and need to know about atrial fibrillation

    Directory of Open Access Journals (Sweden)

    McCabe PJ

    2011-11-01

    Full Text Available Pamela J McCabe Saint Mary's Hospital, Mayo Clinic, Rochester, MN, USA Abstract: Clinicians in a variety of settings are called upon to care for patients diagnosed with atrial fibrillation (AF, a common chronic condition that affects up to 3 million people in the USA. Evidence-based guidelines provide clinicians with direction for treatment of AF, but recommended content for educating patients and counseling about self-management of AF is not included in published guidelines. When patients believe they have a good understanding of AF they report fewer symptoms, perceive greater control over AF, and attribute less emotional distress to AF. Thus, providing patients with information about AF and how to manage it is important for promoting positive outcomes. The purpose of this article is to offer evidence-based recommendations for content to include in self-management education and counseling for patients with AF. Approaches for educating and counseling patients related to AF pathophysiology, the nature of AF (its cause, consequences, and trajectory, treatments, action plans, and symptom management, and managing the psychosocial challenges of living with AF, are discussed. Keywords: atrial fibrillation, patient education, self-management education, counseling

  5. Morphology and mechanical properties of multi-stranded amyloid fibrils probed by atomistic and coarse-grained simulations

    International Nuclear Information System (INIS)

    Yoon, Gwonchan; Lee, Myeongsang; Kim, Kyungwoo; In Kim, Jae; Joon Chang, Hyun; Baek, Inchul; Na, Sungsoo; Eom, Kilho

    2015-01-01

    Amyloid fibrils are responsible for pathogenesis of various diseases and exhibit the structural feature of an ordered, hierarchical structure such as multi-stranded helical structure. As the multi-strandedness of amyloid fibrils has recently been found to be highly correlated with their toxicity and infectivity, it is necessary to study how the hierarchical (i.e. multi-stranded) structure of amyloid fibril is formed. Moreover, although it has recently been reported that the nanomechanics of amyloid proteins plays a key role on the amyloid-induced pathogenesis, a critical role that the multi-stranded helical structure of the fibrils plays in their nanomechanical properties has not fully characterized. In this work, we characterize the morphology and mechanical properties of multi-stranded amyloid fibrils by using equilibrium molecular dynamics simulation and elastic network model. It is shown that the helical pitch of multi-stranded amyloid fibril is linearly proportional to the number of filaments comprising the amyloid fibril, and that multi-strandedness gives rise to improving the bending rigidity of the fibril. Moreover, we have also studied the morphology and mechanical properties of a single protofilament (filament) in order to understand the effect of cross-β structure and mutation on the structures and mechanical properties of amyloid fibrils. Our study sheds light on the underlying design principles showing how the multi-stranded amyloid fibril is formed and how the structure of amyloid fibrils governs their nanomechanical properties. (paper)

  6. Uncommon presentation of cryptogenic organizing pneumonia with miliary pattern in the thorax; Ungewoehnliche Manifestation einer kryptogen organisierenden Pneumonie mit miliarem Verschattungsmuster im Thorax

    Energy Technology Data Exchange (ETDEWEB)

    Langen, H.J.; Biewener, C. [Missionsaerztliche Klinik, Radiologische Abteilung, Wuerzburg (Germany); Ruediger, T. [Universitaet Wuerzburg, Pathologisches Institut, Wuerzburg (Germany); Jany, B. [Missionsaerztliche Klinik, Abteilung fuer Innere Medizin, Wuerzburg (Germany)

    2008-03-15

    A 28-year-old female with worsening dyspnea showed miliary nodules of 2 mm in diameter on chest X-ray and high-resolution CT (HRCT). Histological evaluation and clinical outcome revealed an uncommon presentation of cryptogenic organizing pneumonia. (orig.) [German] Bei einer 28-jaehrigen Patientin mit zunehmender Dyspnoe wurden auf der Thoraxroentgenaufnahme und in der hochaufloesenden CT (HRCT) homogen verteilte monomorphe miliare Fleckschatten von ca. 2 mm Durchmesser nachgewiesen. Die histologische Sicherung und der klinische Verlauf ergaben eine kryptogen organisierende Pneumonie, die sich bildmorphologisch ungewoehnlicherweise nur mit miliaren Knoetchen manifestierte. (orig.)

  7. Entwicklung einer Methode zur monetären Bewertung des Wassers für ein Unternehmen unter Einbeziehung des Wasser-Fußabdrucks

    OpenAIRE

    Hentschel, Nora

    2011-01-01

    Wassernutzung und Abbau der Frischwasser-Ressourcen sind heutzutage ein Thema, das als so wichtig wahrgenommen wird wie der Klimawandel. Wasser wird somit zunehmend Auswirkungen auf den ökonomischen Wert von Unternehmen haben. Ziel der vorliegenden Arbeit ist es, den monetären Wert des Wassers mithilfe des Wasser-Fußabdrucks zu bestimmen. Hierfür werden nach einer kurzen Einführung in Kapitel 2 der ökologische Fußabdruck, der CO2-Fußabdruck und der Wasser-Fußabdruck kurz vorgestellt und in...

  8. Advanced age and incidence of atrial fibrillation in the postoperative period of aortic valve replacement

    Science.gov (United States)

    Pivatto Júnior, Fernando; Teixeira Filho, Guaracy Fernandes; Sant'anna, João Ricardo Michelin; Py, Pablo Mondim; Prates, Paulo Roberto; Nesralla, Ivo Abrahão; Kalil, Renato Abdala Karam

    2014-01-01

    Objective This study aims to describe the correlation between age and occurrence of atrial fibrillation after aortic stenosis surgery in the elderly as well as evaluate the influence of atrial fibrillation on the incidence of strokes, hospital length of stay, and hospital mortality. Methods Cross-sectional retrospective study of > 70 year-old patients who underwent isolated aortic valve replacement. Results 348 patients were included in the study (mean age 76.8±4.6 years). Overall, post-operative atrial fibrillation was 32.8% (n=114), but it was higher in patients aged 80 years and older (42.9% versus 28.8% in patients aged 70-79 years, P=0.017). There was borderline significance for linear correlation between age and atrial fibrillation (P=0.055). Intensive Care Unit and hospital lengths of stay were significantly increased in atrial fibrillation (Patrial fibrillation. Conclusion Post-operative atrial fibrillation incidence in aortic valve replacement is high and correlates with age in patients aged 70 years and older and significantly more pronounced in patients aged 80 years. There was increased length of stay at Intensive Care Unit and hospital, but there was no increase in mortality or stroke. These data are important for planning prophylaxis and early treatment for this subgroup. PMID:24896162

  9. Longitudinal and concurrent dimensional changes of cellulose aggregate fibrils during sorption stages

    International Nuclear Information System (INIS)

    Lee, Jung Myoung; Pawlak, Joel J.; Heitmann, John A.

    2010-01-01

    Atomic force microscopy (AFM) studies of the dimensional changes of cellulose microfibril materials, called cellulose aggregate fibrils (approx. 100 μm x 3 μm x 300 nm), exposed to two distinct relative humidities of 80% and 23% for 24 h and then suddenly subjected to 50% RH and 23 deg. C show that the fibrils are responsive to the surrounding environments in a nonspecific fashion. AFM images (10 μm x 10 μm) of the individual straight cellulose aggregate fibrils were taken as a function of elapsed time during both desorption and adsorption of moisture. The longitudinal distance between discrete natural defects observed on the cellulose aggregate fibrils as well as the width, cross-sectional area, and height of the cellulose aggregate fibril were measured from the AFM images. The length of the cellulose aggregate fibrils was found to have reduced after exposure to either high or low relative humidity, and then placement in ambient conditions. Over time in ambient conditions, the cellulose aggregate fibrils progressively relaxed to their original length during both desorption and adsorption of moisture. However, the relaxation rate during adsorption was faster than that during desorption. The possible explanations for this phenomenon are discussed including the sample preparation method, volume conservation, entropy elasticity, and free volume theory. The changes in the width, height, and cross-sectional area are also discussed.

  10. Ionic Strength Modulation of the Free Energy Landscape of Aβ40 Peptide Fibril Formation.

    Science.gov (United States)

    Abelein, Axel; Jarvet, Jüri; Barth, Andreas; Gräslund, Astrid; Danielsson, Jens

    2016-06-01

    Protein misfolding and formation of cross-β structured amyloid fibrils are linked to many neurodegenerative disorders. Although recently developed quantitative approaches have started to reveal the molecular nature of self-assembly and fibril formation of proteins and peptides, it is yet unclear how these self-organization events are precisely modulated by microenvironmental factors, which are known to strongly affect the macroscopic aggregation properties. Here, we characterize the explicit effect of ionic strength on the microscopic aggregation rates of amyloid β peptide (Aβ40) self-association, implicated in Alzheimer's disease. We found that physiological ionic strength accelerates Aβ40 aggregation kinetics by promoting surface-catalyzed secondary nucleation reactions. This promoted catalytic effect can be assigned to shielding of electrostatic repulsion between monomers on the fibril surface or between the fibril surface itself and monomeric peptides. Furthermore, we observe the formation of two different β-structured states with similar but distinct spectroscopic features, which can be assigned to an off-pathway immature state (Fβ*) and a mature stable state (Fβ), where salt favors formation of the Fβ fibril morphology. Addition of salt to preformed Fβ* accelerates transition to Fβ, underlining the dynamic nature of Aβ40 fibrils in solution. On the basis of these results we suggest a model where salt decreases the free-energy barrier for Aβ40 folding to the Fβ state, favoring the buildup of the mature fibril morphology while omitting competing, energetically less favorable structural states.

  11. In vitro fibrillization of Alzheimer’s amyloid-β peptide (1-42)

    Energy Technology Data Exchange (ETDEWEB)

    Tiiman, Ann [Department of Gene Technology, Tallinn University of Technology, Tallinn 12618 (Estonia); Department of Biochemistry and Biophysics, Arrhenius Laboratories, Stockholm University, Stockholm, 106 91 (Sweden); Krishtal, Jekaterina; Palumaa, Peep; Tõugu, Vello, E-mail: vello.tougu@ttu.ee [Department of Gene Technology, Tallinn University of Technology, Tallinn 12618 (Estonia)

    2015-09-15

    The amyloid deposition in the form of extracellular fibrillar aggregates of amyloid-β (Aβ) peptide is a critical pathological event in Alzheimer’s disease. Here, we report a systematic investigation of the effects of environmental factors on the kinetics of Aβ fibrillization in vitro. The effects of Aβ42 peptide concentration, temperature, pH, added solvents and the ratio of Aβ40 and Aβ42 on the peptide fibrillization under agitated conditions was studied. The analysis show that the rate of fibril growth by monomer addition is not limited by diffusion but by rearrangement in the monomer structure, which is enhanced by low concentrations of fluorinated alcohols and characterized by the activation energy of 12 kcal/mol. Fibrillization rate decreases at pH values below 7.0 where simultaneous protonation of His 13 and 14 inhibits fibril formation. The lag period for Aβ42 was only twofold shorter and the fibril growth rate twofold faster than those of Aβ40. Lag period was shortened and the fibrillization rate was increased only at 90% content of Aβ42.

  12. MAK33 antibody light chain amyloid fibrils are similar to oligomeric precursors.

    Directory of Open Access Journals (Sweden)

    Manuel Hora

    Full Text Available Little structural information is available so far on amyloid fibrils consisting of immunoglobulin light chains. It is not understood which features of the primary sequence of the protein result in fibril formation. We report here MAS solid-state NMR studies to identify the structured core of κ-type variable domain light chain fibrils. The core contains residues of the CDR2 and the β-strands D, E, F and G of the native immunoglobulin fold. The assigned core region of the fibril is distinct in comparison to the core identified in a previous solid-state NMR study on AL-09 by Piehl at. al, suggesting that VL fibrils can adopt different topologies. In addition, we investigated a soluble oligomeric intermediate state, previously termed the alternatively folded state (AFS, using NMR and FTIR spectroscopy. The NMR oligomer spectra display a high degree of similarity when compared to the fibril spectra, indicating a high structural similarity of the two aggregation states. Based on comparison to the native state NMR chemical shifts, we suggest that fibril formation via domain-swapping seems unlikely. Moreover, we used our results to test the quality of different amyloid prediction algorithms.

  13. Structure–mechanics relationships of collagen fibrils in the osteogenesis imperfecta mouse model

    Science.gov (United States)

    Andriotis, O. G.; Chang, S. W.; Vanleene, M.; Howarth, P. H.; Davies, D. E.; Shefelbine, S. J.; Buehler, M. J.; Thurner, P. J.

    2015-01-01

    The collagen molecule, which is the building block of collagen fibrils, is a triple helix of two α1(I) chains and one α2(I) chain. However, in the severe mouse model of osteogenesis imperfecta (OIM), deletion of the COL1A2 gene results in the substitution of the α2(I) chain by one α1(I) chain. As this substitution severely impairs the structure and mechanics of collagen-rich tissues at the tissue and organ level, the main aim of this study was to investigate how the structure and mechanics are altered in OIM collagen fibrils. Comparing results from atomic force microscopy imaging and cantilever-based nanoindentation on collagen fibrils from OIM and wild-type (WT) animals, we found a 33% lower indentation modulus in OIM when air-dried (bound water present) and an almost fivefold higher indentation modulus in OIM collagen fibrils when fully hydrated (bound and unbound water present) in phosphate-buffered saline solution (PBS) compared with WT collagen fibrils. These mechanical changes were accompanied by an impaired swelling upon hydration within PBS. Our experimental and atomistic simulation results show how the structure and mechanics are altered at the individual collagen fibril level as a result of collagen gene mutation in OIM. We envisage that the combination of experimental and modelling approaches could allow mechanical phenotyping at the collagen fibril level of virtually any alteration of collagen structure or chemistry. PMID:26468064

  14. A biomechanical model for fibril recruitment: Evaluation in tendons and arteries.

    Science.gov (United States)

    Bevan, Tim; Merabet, Nadege; Hornsby, Jack; Watton, Paul N; Thompson, Mark S

    2018-06-06

    Simulations of soft tissue mechanobiological behaviour are increasingly important for clinical prediction of aneurysm, tendinopathy and other disorders. Mechanical behaviour at low stretches is governed by fibril straightening, transitioning into load-bearing at recruitment stretch, resulting in a tissue stiffening effect. Previous investigations have suggested theoretical relationships between stress-stretch measurements and recruitment probability density function (PDF) but not derived these rigorously nor evaluated these experimentally. Other work has proposed image-based methods for measurement of recruitment but made use of arbitrary fibril critical straightness parameters. The aim of this work was to provide a sound theoretical basis for estimating recruitment PDF from stress-stretch measurements and to evaluate this relationship using image-based methods, clearly motivating the choice of fibril critical straightness parameter in rat tail tendon and porcine artery. Rigorous derivation showed that the recruitment PDF may be estimated from the second stretch derivative of the first Piola-Kirchoff tissue stress. Image-based fibril recruitment identified the fibril straightness parameter that maximised Pearson correlation coefficients (PCC) with estimated PDFs. Using these critical straightness parameters the new method for estimating recruitment PDF showed a PCC with image-based measures of 0.915 and 0.933 for tendons and arteries respectively. This method may be used for accurate estimation of fibril recruitment PDF in mechanobiological simulation where fibril-level mechanical parameters are important for predicting cell behaviour. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Lysosomal enzyme cathepsin B enhances the aggregate forming activity of exogenous α-synuclein fibrils.

    Science.gov (United States)

    Tsujimura, Atsushi; Taguchi, Katsutoshi; Watanabe, Yoshihisa; Tatebe, Harutsugu; Tokuda, Takahiko; Mizuno, Toshiki; Tanaka, Masaki

    2015-01-01

    The formation of intracellular aggregates containing α-synuclein (α-Syn) is one of the key steps in the progression of Parkinson's disease and dementia with Lewy bodies. Recently, it was reported that pathological α-Syn fibrils can undergo cell-to-cell transmission and form Lewy body-like aggregates. However, little is known about how they form α-Syn aggregates from fibril seeds. Here, we developed an assay to study the process of aggregate formation using fluorescent protein-tagged α-Syn-expressing cells and examined the aggregate forming activity of exogenous α-Syn fibrils. α-Syn fibril-induced formation of intracellular aggregates was suppressed by a cathepsin B specific inhibitor, but not by a cathepsin D inhibitor. α-Syn fibrils pretreated with cathepsin B in vitro enhanced seeding activity in cells. Knockdown of cathepsin B also reduced fibril-induced aggregate formation. Moreover, using LAMP-1 immunocytochemistry and live-cell imaging, we observed that these aggregates initially occurred in the lysosome. They then rapidly grew larger and moved outside the boundary of the lysosome within one day. These results suggest that the lysosomal protease cathepsin B is involved in triggering intracellular aggregate formation by α-Syn fibrils. Copyright © 2015. Published by Elsevier Inc.

  16. Stroke prevention in hospitalized patients with atrial fibrillation: a population-based study.

    Science.gov (United States)

    Nagpal, Seema; Anderson, David; Putnam, Wayne; Flowerdew, Gordon; Gardner, Martin; Cox, Jafna

    2003-01-01

    Oral anticoagulants reduce the incidence of stroke by 68%, yet suboptimal use has been documented in surveys of patients with atrial fibrillation. The present study examined current patterns of anticoagulant use for patients hospitalized with atrial fibrillation across an entire health care system. Improving Cardiovascular Outcomes in Nova Scotia (ICONS) is a prospective cohort study involving all patients hospitalized in Nova Scotia with atrial fibrillation, among other conditions. Consecutive inpatients with atrial fibrillation from October 15, 1997 to October 14, 1998 were studied. Detailed demographic and clinical data were collected and the proportion of patients using antithrombotic therapy was tabulated by risk category. Multivariate logistic regression was used to assess the relationship of various demographic and clinical factors with the use of antithrombotic agents. There were 2202 patients hospitalized with atrial fibrillation; 644 admitted specifically for this condition. Only 21% of patients admitted with atrial fibrillation were on warfarin sodium at admission and this increased by time of discharge. Diabetes was negatively correlated with warfarin sodium use. Histories of prosthetic valve replacement, stroke/transient ischemic attack, and heart failure were positively associated with anticoagulant use on admission. Patients with prosthetic valve replacement, heart failure, or hyperlipidemia were most likely to receive anticoagulants at discharge. Antithrombotic agents remain underused by patients with atrial fibrillation. While higher risk patients are generally targeted, this is not invariably the case; thus, diabetics remain under treated. Further work is needed to explain such anomalous practice and promote optimal antithrombotic therapy use.

  17. Cardiac monitoring for detection of atrial fibrillation after TIA: A systematic review and meta-analysis.

    Science.gov (United States)

    Korompoki, Eleni; Del Giudice, Angela; Hillmann, Steffi; Malzahn, Uwe; Gladstone, David J; Heuschmann, Peter; Veltkamp, Roland

    2017-01-01

    Background and purpose The detection rate of atrial fibrillation has not been studied specifically in transient ischemic attack (TIA) patients although extrapolation from ischemic stroke may be inadequate. We conducted a systematic review and meta-analysis to determine the rate of newly diagnosed atrial fibrillation using different methods of ECG monitoring in TIA. Methods A comprehensive literature search was performed following a pre-specified protocol the PRISMA statement. Prospective observational studies and randomized controlled trials were considered that included TIA patients who underwent cardiac monitoring for >12 h. Primary outcome was frequency of detection of atrial fibrillation ≥30 s. Analyses of subgroups and of duration and type of monitoring were performed. Results Seventeen studies enrolling 1163 patients were included. The pooled atrial fibrillation detection rate for all methods was 4% (95% CI: 2-7%). Yield of monitoring was higher in selected (higher age, more extensive testing for arrhythmias before enrolment, or presumed cardioembolic/cryptogenic cause) than in unselected cohorts (7% vs 3%). Pooled mean atrial fibrillation detection rates rose with duration of monitoring: 4% (24 h), 5% (24 h to 7 days) and 6% (>7 days), respectively. Yield of non-invasive was significantly lower than that of invasive monitoring (4% vs. 11%). Significant heterogeneity was observed among studies (I 2 =60.61%). Conclusion This first meta-analysis of atrial fibrillation detection in TIA patients finds a lower atrial fibrillation detection rate in TIA than reported for IS and TIA cohorts in previous meta-analyses. Prospective studies are needed to determine actual prevalence of atrial fibrillation and optimal diagnostic procedure for atrial fibrillation detection in TIA.

  18. Atrial fibrillation screening in pharmacies using an iPhone ECG: a qualitative review of implementation.

    Science.gov (United States)

    Lowres, Nicole; Krass, Ines; Neubeck, Lis; Redfern, Julie; McLachlan, Andrew J; Bennett, Alexandra A; Freedman, S Ben

    2015-12-01

    Atrial fibrillation guidelines advocate screening to identify undiagnosed atrial fibrillation. Community pharmacies may provide an opportunistic venue for such screening. To explore the experience of implementing an atrial fibrillation screening service from the pharmacist's perspective including: the process of study implementation; the perceived benefits; the barriers and enablers; and the challenges for future sustainability of atrial fibrillation screening within pharmacies. Setting Interviews were conducted face-to-face in the pharmacy or via telephone, according to pharmacist preference. The 'SEARCH-AF study' screened 1000 pharmacy customers aged ≥65 years using an iPhone electrocardiogram, identifying 1.5 % with undiagnosed atrial fibrillation. Nine pharmacists took part in semi-structured interviews. Interviews were transcribed in full and thematically analysed. Qualitative analysis of the experience of implementing an AF screening service from the pharmacist's perspective. Four broad themes relating to service provision were identified: (1) interest and engagement in atrial fibrillation screening by pharmacists, customers, and doctors with the novel, easy-to-use electrocardiogram technology serving as an incentive to undergo screening and an education tool for pharmacists to use with customers; (2) perceived benefits to the pharmacist including increased job satisfaction, improvement in customer relations and pharmacy profile by fostering enhanced customer care and the educational role of pharmacists; (3) implementation barriers including managing workflow, and enablers such as personal approaches for recruitment, and allocating time to discuss screening process and fears; and, (4) potential for sustainable future implementation including remuneration linked to government or pharmacy incentives, combined cardiovascular screening, and automating sections of risk-assessments using touch-screen technology. Atrial fibrillation screening in pharmacies is well

  19. The Effect of Milk Constituents and Crowding Agents on Amyloid Fibril Formation by κ-Casein.

    Science.gov (United States)

    Liu, Jihua; Dehle, Francis C; Liu, Yanqin; Bahraminejad, Elmira; Ecroyd, Heath; Thorn, David C; Carver, John A

    2016-02-17

    When not incorporated into the casein micelle, κ-casein, a major milk protein, rapidly forms amyloid fibrils at physiological pH and temperature. In this study, the effects of milk components (calcium, lactose, lipids, and heparan sulfate) and crowding agents on reduced and carboxymethylated (RCM) κ-casein fibril formation was investigated using far-UV circular dichroism spectroscopy, thioflavin T binding assays, and transmission electron microscopy. Longer-chain phosphatidylcholine lipids, which form the lining of milk ducts and milk fat globules, enhanced RCM κ-casein fibril formation irrespective of whether the lipids were in a monomeric or micellar state, whereas shorter-chain phospholipids and triglycerides had little effect. Heparan sulfate, a component of the milk fat globule membrane and catalyst of amyloid deposition in extracellular tissue, had little effect on the kinetics of RCM κ-casein fibril formation. Major nutritional components such as calcium and lactose also had no significant effect. Macromolecular crowding enhances protein-protein interactions, but in contrast to other fibril-forming species, the extent of RCM κ-casein fibril formation was reduced by the presence of a variety of crowding agents. These data are consistent with a mechanism of κ-casein fibril formation in which the rate-determining step is dissociation from the oligomer to give the highly amyloidogenic monomer. We conclude that the interaction of κ-casein with membrane-associated phospholipids along its secretory pathway may contribute to the development of amyloid deposits in mammary tissue. However, the formation of spherical oligomers such as casein micelles is favored over amyloid fibrils in the crowded environment of milk, within which the occurrence of amyloid fibrils is low.

  20. Evidence for novel beta-sheet structures in Iowa mutant beta-amyloid fibrils.

    Science.gov (United States)

    Tycko, Robert; Sciarretta, Kimberly L; Orgel, Joseph P R O; Meredith, Stephen C

    2009-07-07

    Asp23-to-Asn mutation within the coding sequence of beta-amyloid, called the Iowa mutation, is associated with early onset, familial Alzheimer's disease and cerebral amyloid angiopathy, in which patients develop neuritic plaques and massive vascular deposition predominantly of the mutant peptide. We examined the mutant peptide, D23N-Abeta40, by electron microscopy, X-ray diffraction, and solid-state NMR spectroscopy. D23N-Abeta40 forms fibrils considerably faster than the wild-type peptide (k = 3.77 x 10(-3) min(-1) and 1.07 x 10(-4) min(-1) for D23N-Abeta40 and the wild-type peptide WT-Abeta40, respectively) and without a lag phase. Electron microscopy shows that D23N-Abeta40 forms fibrils with multiple morphologies. X-ray fiber diffraction shows a cross-beta pattern, with a sharp reflection at 4.7 A and a broad reflection at 9.4 A, which is notably smaller than the value for WT-Abeta40 fibrils (10.4 A). Solid-state NMR measurements indicate molecular level polymorphism of the fibrils, with only a minority of D23N-Abeta40 fibrils containing the in-register, parallel beta-sheet structure commonly found in WT-Abeta40 fibrils and most other amyloid fibrils. Antiparallel beta-sheet structures in the majority of fibrils are indicated by measurements of intermolecular distances through (13)C-(13)C and (15)N-(13)C dipole-dipole couplings. An intriguing possibility exists that there is a relationship between the aberrant structure of D23N-Abeta40 fibrils and the unusual vasculotropic clinical picture in these patients.