36 results on '"F Funke"'
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2. Experimental and modelling studies of iodine oxide formation and aerosol behaviour relevant to nuclear reactor accidents
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B. Clément, L. Bosland, Y. Ammar, Sabrina Tietze, Gunther H. Weber, Ari Auvinen, G. Glowa, Teemu Kärkelä, S. Dickinson, S. Zhang, F. Funke, D. A. Powers, Newcastle University [Newcastle], Institut de Radioprotection et de Sûreté Nucléaire (IRSN), AECL, Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH, and European Commission, EC 237147
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[PHYS]Physics [physics] ,iodine ,aerosol ,severe accidents ,chemistry.chemical_element ,Iodine oxide ,Nuclear reactor ,Iodine ,iodine oxide ,law.invention ,Aerosol ,Reaction rate ,Atmosphere ,radiation ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,13. Climate action ,law ,Environmental chemistry ,Radiolysis ,methyl iodine ,Environmental science ,Volatility (chemistry) - Abstract
International audience; Plant assessments have shown that iodine contributes significantly to the source term for a range of accident scenarios. Iodine has a complex chemistry that determines its chemical form and, consequently, its volatility in the containment. If volatile iodine species are formed by reactions in the containment, they will be subject to radiolytic reactions in the atmosphere, resulting in the conversion of the gaseous species into involatile iodine oxides, which may deposit on surfaces or re-dissolve in water pools. The concentration of airborne iodine in the containment will, therefore, be determined by the balance between the reactions contributing to the formation and destruction of volatile species, as well as by the physico-chemical properties of the iodine oxide aerosols which will influence their longevity in the atmosphere. This paper summarises the work that has been done in the framework of the EC SARNET (Severe Accident Research Network) to develop a greater understanding of the reactions of gaseous iodine species in irradiated air/steam atmospheres, and the nature and behaviour of the reaction products. This work has mainly been focussed on investigating the nature and behaviour of iodine oxide aerosols, but earlier work by members of the SARNET group on gaseous reaction rates is also discussed to place the more recent work into context. © 2014 Elsevier Ltd. All rights reserved.
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- 2014
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3. Thermal-hydraulic-iodine chemistry coupling: Insights gained from the SARNET benchmark on the THAI experiments Iod-11 and Iod-12
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Joan Fontanet, Bruno Gonfiotti, Luis E. Herranz, Sandro Paci, Gunter Weber, S. Krajewski, Tuomo Sevón, Ivan B. Ivanov, F. Funke, A. Manfredini, M. Bendiab, and M. Pelzer
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Coupling ,Nuclear and High Energy Physics ,Engineering ,business.industry ,Chemistry ,020209 energy ,Mechanical Engineering ,Nuclear engineering ,02 engineering and technology ,01 natural sciences ,010305 fluids & plasmas ,Thermal hydraulics ,Nuclear Energy and Engineering ,MELCOR ,Benchmark (surveying) ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Relative humidity ,Safety, Risk, Reliability and Quality ,business ,Waste Management and Disposal ,Simulation - Abstract
In the SARNET2 WP8.3 THAI Benchmark the capability of current accident codes to simulate the iodine transport and behavior in sub-divided containments has been assessed. In THAI test Iod-11 and Iod-12, made available for the benchmark, the distribution of molecular iodine (I2) in the five compartments of the 60 m3 vessel under stratified and well mixed conditions was measured. The main processes addressed are the I2 transport with the atmospheric flows and the interaction of I2 with the steel surface. During test Iod-11 the surfaces in contact with the containment atmosphere were dry. In Iod-12, steam was released, which condensed on the walls.Nine post-test calculations were conducted for Iod-11 and eight for Iod-12 by seven organizations using four different codes: ASTEC-IODE (CIEMAT, GRS and TUS), COCOSYS-AIM (AREVA, FZ-Jülich and GRS), ECART (Pisa University) and MELCOR (Pisa University and VTT). Different nodalizations of the THAI vessel with 20–65 zones were applied.Generally, for both tests the analytical thermal-hydraulic results are in a fairly good agreement with the measurements. Only the calculated local relative humidity deviates significantly from the measured values in all calculations. The results in Iod-11 for the local I2 concentration in the gaseous phase are quite diverse. Three calculations show only minor deviations from the measurement, whereas the others are substantially different from the measured I2 concentrations. For Iod-12, no calculation delivers a satisfactory evolution of the I2 concentration in all five compartments of the vessel. There are three mediocre results standing out in the Iod-11 exercise which are from the same user–code combinations. The discrepancies derive from various reasons which are discussed in the paper.In the benchmark a significant user effect was detected, i.e. results achieved with the same code differed considerably.This work highlights the need of a detailed iodine adsorption/desorption model and precise thermal-hydraulic modeling for an accurate simulation of I2 transport in a sub-divided containment, as well as experienced users or straight forward user guidelines.
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- 2013
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4. LWR severe accident simulation Iodine behaviour in FPT2 experiment and advances on containment iodine chemistry
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S. Güntay, Luis E. Herranz, L. Bosland, N. Girault, Dana Auburn Powers, S. Dickinson, F. Funke, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), SwissFEL, Paul Scherrer Institut, and Sandia National Laboratories - Corporation
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[PHYS]Physics [physics] ,Nuclear and High Energy Physics ,Fission products ,Nuclear fission product ,010504 meteorology & atmospheric sciences ,020209 energy ,Mechanical Engineering ,Radiochemistry ,Uranium dioxide ,chemistry.chemical_element ,Iodine oxide ,02 engineering and technology ,Iodine ,01 natural sciences ,Sump (aquarium) ,Coolant ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,General Materials Science ,Current (fluid) ,Safety, Risk, Reliability and Quality ,Waste Management and Disposal ,0105 earth and related environmental sciences - Abstract
International audience; The Phebus Fission Product (FP) Program studies key phenomena of severe accidents in water-cooled nuclear reactors. In the framework of the Phebus program, five in-pile experiments have been performed that cover fuel rod degradation and behaviour of fission products released via the coolant circuit into the containment vessel. The focus of this paper is on iodine behaviour during the Phebus FPT2 test. FPT2 used a 33 GWd/t uranium dioxide fuel enriched to 4.5%, re-irradiated in situ for 7 days to a burn-up of 130 MWd/t. This test was performed to study the impact of steam-poor conditions and boric acid on the fission product chemistry. For the containment vessel, more specifically, the objective was to study iodine chemistry in an alkaline sump under evaporating conditions. The iodine results of the Phebus FPT2 test confirmed many of the essential features of iodine behaviour in the containment vessel provided by the first two Phebus tests, FPT0 and FPT1. These are the existence of an early gaseous iodine fraction, the persistence of low gaseous iodine concentrations and the importance of the sump in suppressing the iodine partitioning from sump to atmosphere. The main new insights provided by the Phebus FPT2 test were the iodine desorption from stainless steel walls deposits and the role of the evaporating sump in further iodine depletion in the containment atmosphere. The current paper presents an interpretation of the iodine behaviour in the FPT2 containment vessel based on dedicated small-scale analytical experiments and computer codes calculations. Other investigations dealing with primary circuit and sump chemistry are also reported. These could help to scale the results of Phebus-FP tests to reactor accidents. Modelling studies were generally successful when a gaseous iodine injection from the primary circuit was assumed. Indeed, though each of the iodine codes has specific iodine chemistry features that should be further developed and each approach to the modelling is distinct, the overall iodine behaviour in the FPT2 containment is generally well reproduced by the models that predicta low final gaseous iodine concentration in the containment atmosphere,a predominant iodine concentration in the sump and to a lesser extent a significant iodine deposition on containment surfaces. The main code-to-code differences, in the results obtained in gaseous iodine speciation, come from the various treatments of gaseous radiolytic reactions. Calculations that include the radiolytic conversion of volatile iodine into iodine oxide particulate show there is a persistence of both gaseous iodine and iodine oxide particles in the atmosphere. There are also some variations between the predicted organic iodine concentrations that depend mainly on the initial assumptions. A key aspect of the Phebus FPT2 test interpretation is that the long term iodine behaviour in the containment can be explained by exchanges between organic iodide released from painted surfaces and inorganic iodine released from deposited aerosol on the containment walls. Further studies of regulatory significance on sump chemistry showed that the gaseous iodine control that was evident in the Phebus tests through silver release and/or alkaline buffered sump solutions may not be assured. As most of the past iodine aqueous chemistry studies were done with rather pure systems and because of the uncompleted understanding of the gaseous iodine speciation, the results may not be extrapolated easily to conditions of reactor accidents thus necessitating deeper investigations. © 2011 Elsevier B.V. All rights reserved.
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- 2012
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5. Recent advances on containment iodine chemistry
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G. Ducros, L. Cantrel, Teemu Kärkelä, Joachim Holm, Christos Housiadas, F. Funke, Luis E. Herranz, N. Girault, C. Mun, Jean-Christophe Sabroux, S. Dickinson, S. Guilbert, J. Ball, F. Andreo, L. Bosland, G. Weber, EDF (EDF), VTT Technical Research Centre of Finland (VTT), Atomic Energy of Canada Limited (AECL), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Groupe AREVA, Chalmers University of Technology [Göteborg], Centro de Investigaciones Energéticas Medioambientales y Tecnológicas [Madrid] (CIEMAT), National Centre for Scientific Research 'Demokritos', Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH
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020209 energy ,Energy Engineering and Power Technology ,chemistry.chemical_element ,Radiation effects ,Reviews ,Iodine Chemistry ,02 engineering and technology ,Iodine ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Cesium iodide ,Humid atmospheres ,law ,0103 physical sciences ,Particulate species ,0202 electrical engineering, electronic engineering, information engineering ,Integral experiments ,Light-water reactor ,Mass transfer ,Radiation-induced ,Safety, Risk, Reliability and Quality ,Process engineering ,Waste Management and Disposal ,Severe accident ,LWR Severe Accident ,Complex chemical phenomena ,[PHYS]Physics [physics] ,business.industry ,Scale (chemistry) ,Cadmium compounds ,Light water reactors ,Experimental data ,Containment ,Nuclear reactor ,Iodine depletion ,Nuclear Energy and Engineering ,chemistry ,Accidents ,Small-scale experiment ,business ,Test data - Abstract
The 5th FWP EURSAFE Project highlighted iodine chemistry in the containment as one of the issues requiring further research in order to reduce source term uncertainties. Consequently, a series of studies was launched in the 6th FWP SARNET Project aimed at improving the predictability of iodine behaviour during severe accidents via a better understanding of the complex chemical phenomena in the containment. In particular, SARNET has striven to foster common interpretation of integral and separate effect test data, production of new or improved models where necessary, and compilation of the existing knowledge of the subject. The work has been based on a substantial amount of experimental information made available from bench-scale projects (PARIS and EPICUR), via intermediate-scale tests (CAIMAN) to large-scale facilities (SISYPHE, THAI and PHEBUS-FP). In the experimental field, particular attention has been paid to two specific issues: the effects of radiation on both aqueous and gaseous iodine chemistry, and the mass transfer of iodine between aqueous and gaseous phases. Comparisons between calculations and results of the EPICUR and CAIMAN experiments suggest that the aqueous phase chemistry is reasonably well understood, although there are still some areas of uncertainty. Interpretation of integral experiments, like PHEBUS-FPT2, indicated that radiation-induced conversion of molecular iodine into particulate species (IxOy) could be responsible for the gaseous iodine depletion observed in the long-term. However, the results of much simpler, small-scale experiments have shown that further improvements in understanding and modelling are still needed. Mass transfer modelling has been extended to cover evaporating sump conditions based on SISYPHE data; however, application of this model to the larger scale THAI experiments seems not to be straightforward. In addition to these two major issues, some specific studies have been carried out concerning the potential effect of passive autocatalytic hydrogen recombiners on iodine volatility. The RECI analytical experiments have shown that metal iodides (namely CsI and CdI2) are not stable and yield gaseous iodine when heated, in a humid atmosphere, at temperatures representative of recombiner operation. Another important undertaking successfully carried out has been the compilation of an Iodine Data Book, which provides a critical review of the experimental data and modelling approaches that have been used in the development of iodine source term methodologies. This should assist in a proper use of such models, and inform their future development.
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- 2010
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6. Iodine behaviour under LWR accident conditions: Lessons learnt from analyses of the first two Phebus FP tests
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S. Dickinson, Luis E. Herranz, Ari Auvinen, Elisabeth Krausmann, F. Funke, N. Girault, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), FRAMATOME-ANP, VTT Technical Research Centre of Finland (VTT), Centro de Investigaciones Energéticas Medioambientales y Tecnológicas [Madrid] (CIEMAT), JRC Institute for Energy and Transport (IET), and European Commission - Joint Research Centre [Petten]
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Nuclear and High Energy Physics ,Nuclear fission product ,020209 energy ,Nuclear engineering ,Containment building ,accidents ,02 engineering and technology ,Fission products ,01 natural sciences ,Fuel degradation ,light water reactors ,010305 fluids & plasmas ,law.invention ,law ,0103 physical sciences ,Oxidation ,0202 electrical engineering, electronic engineering, information engineering ,Forensic engineering ,nuclear power plants ,General Materials Science ,Light-water reactor ,LWR ,Volatile organic compounds ,Safety, Risk, Reliability and Quality ,Waste Management and Disposal ,[PHYS]Physics [physics] ,Coolants ,Vaporization ,iodine ,nuclear reactor accidents ,Mechanical Engineering ,Light water reactors ,Pressurized water reactor ,Pressurized water reactors ,Nuclear reactor ,Computer code analyses ,Coolant ,Nuclear Energy and Engineering ,Containment ,13. Climate action ,LWR accidents ,Iodine radiochemistry ,Iodine - Abstract
The International Phebus Fission Product programme, initiated in 1988 and performed by the French "Institut de Radioprotection et de Sûreté Nucléaire" (IRSN), investigates through a series of in-pile integral experiments, key phenomena involved in light water reactor (LWR) severe accidents. The tests cover fuel rod degradation and the behaviour of fission products released via the primary coolant circuit into the containment building. The results of the first two tests, called FPT0 and FPT1, carried out under low pressure, in a steam rich atmosphere and using fresh fuel for FPT0 and fuel burned in a reactor at 23 GWdt-1 for FPT1, were immensely challenging, especially with regard to the iodine radiochemistry. Some of the most important observed phenomena with regard to the chemistry of iodine were indeed neither predicted nor pre-calculated, which clearly shows the interest and the need for carrying out integral experiments to study the complex phenomena governing fission product behaviour in a PWR in accident conditions. The three most unexpected results in the iodine behaviour related to early detection during fuel degradation of a weak but significant fraction of volatile iodine in the containment, the key role played by silver rapidly binding iodine to form insoluble AgI in the containment sump and the importance of painted surfaces in the containment atmosphere for the formation of a large quantity of volatile organic iodides. To support the Phebus test interpretation small-scale analytical experiments and computer code analyses were carried out. The former, helping towards a better understanding of overall iodine behaviour, were used to develop or improve models while the latter mainly aimed at identifying relevant key phenomena and at modelling weaknesses. Specific efforts were devoted to exploring the potential origins of the early-detected volatile iodine in the containment building. If a clear explanation has not yet been found, the non-equilibrium chemical processes favoured in the primary coolant circuit and the early radiolytic oxidation of iodides in the condensed water films are at present the most likely explanations. Models that were modified or developed and embodied in the computer codes for organic iodide formation/destruction in the gas phase and Ag-I reactions in the sump lead, in agreement with the Phebus findings respectively to greatly enhanced organic iodide formation kinetics and long term concentration in the containment atmosphere on one hand and, in the conditions of Phebus experiments, to significantly limited molecular iodine volatilisation from the sump in so far as silver was in excess compared to iodine, on the other hand. Organic iodides then quickly gain in importance and become the predominant volatile iodine species at long term. © 2006 Elsevier B.V. All rights reserved.
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- 2006
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7. Organic iodine chemistry
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S. Hellmann, E Belval-Haltier, F. Funke, C Poletiko, Riitta Zilliacus, D Jacquemain, H.E. Sims, T Karjunen, and S. Dickinson
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Nuclear and High Energy Physics ,Code development ,Waste management ,Mechanical Engineering ,Radioactive waste ,chemistry.chemical_element ,Iodine ,law.invention ,Nuclear Energy and Engineering ,chemistry ,law ,Nuclear power plant ,General Materials Science ,Safety, Risk, Reliability and Quality ,Waste Management and Disposal - Abstract
A shared-cost action on Organic Iodine Chemistry has been completed as part of the CEC 4th Framework programme on Nuclear Fission Safety. Organisations from four EC countries are involved in an integrated programme of experiments and analysis to help clarify the phenomenology, and to increase confidence in the modelling of iodine behaviour in containment. The project is focused on identifying the main routes for organic iodine formation, and providing new experimental kinetic data which will be used to improve existing models and to stimulate code development.
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- 2001
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8. Impact of Bronchoscopic Lung Volume Reduction with Valves on the Pulmonary Gas Exchange.
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Winantea J, Stiehl K, Karpf-Wissel R, Funke F, Hautzel H, Schwarz B, Steveling H, Taube C, Oezkan F, and Darwiche K
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Introduction: Bronchoscopic lung volume reduction (BLVR) with endobronchial valves has been shown to be a safe and effective treatment for patients with severe lung emphysema. Previous studies have reported a benefit in pulmonary function, exercise capacity, and quality of life after BLVR-treatment. The effect of BLVR with valves on the pulmonary gas exchange and its association with clinical outcomes has not been analyzed to date. The primary goal of this study was to investigate the impact of BLVR on the pulmonary gas exchange and the impact of the target lobe selection in patients with discordant target lobes in high-resolution computed tomography (HRCT) scan and perfusion scan on the pulmonary gas exchange and clinical outcomes. Methods: In this single-center study, we retrospectively analyzed pulmonary function tests, 6-min-walk-tests, HRCT scans, perfusion scans, and blood gas analyses in 77 patients over the course of 6 months following BLVR treatment. Results: We observed that complete lobar occlusion with bronchoscopic valves leads to a transient impairment of pulmonary gas exchange. Despite this, an overall positive clinical outcome could be shown in patients treated with endobronchial valves. If the target lobe selection based on HRCT and perfusion scans is discrepant, a selection based on the HRCT scan tends to be associated with a better outcome than a selection based on the perfusion scan. Conclusions: Complete lobar occlusion with bronchoscopic valves leads to a transient impairment of pulmonary gas exchange but nevertheless results in an overall positive clinical outcome.
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- 2024
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9. Meat taxes in Europe can be designed to avoid overburdening low-income consumers.
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Klenert D, Funke F, and Cai M
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- Europe, Commerce, Smoking Prevention, Taxes, Poverty
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Consumption taxes on meat have recently been under consideration in several European countries as part of their effort to achieve more sustainable food systems. Yet a major concern is that these taxes might burden low-income households disproportionately. Here we compare different meat tax designs and revenue recycling schemes in terms of their distributional impacts in a large sample of European countries. We find that across all selected tax designs, uncompensated meat taxes are slightly regressive. However, the effect on inequality is mild and can be reversed through revenue recycling via uniform lump-sum transfers in most cases. Using meat tax revenues towards lowering value-added taxes on fruit and vegetable products dampens but does not fully offset the regressive effect. Variation in the distributional impact can be explained by cross-country heterogeneity in consumption patterns, design choices between unit-based and ad valorem taxation and differentiation according to greenhouse gas intensities., (© 2023. The Author(s).)
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- 2023
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10. Investigating the Prevalence of RNA-Binding Metabolic Enzymes in E. coli .
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Klein T, Funke F, Rossbach O, Lehmann G, Vockenhuber M, Medenbach J, Suess B, Meister G, and Babinger P
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- Prevalence, Escherichia coli genetics
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An open research field in cellular regulation is the assumed crosstalk between RNAs, metabolic enzymes, and metabolites, also known as the REM hypothesis. High-throughput assays have produced extensive interactome data with metabolic enzymes frequently found as hits, but only a few examples have been biochemically validated, with deficits especially in prokaryotes. Therefore, we rationally selected nineteen Escherichia coli enzymes from such datasets and examined their ability to bind RNAs using two complementary methods, iCLIP and SELEX. Found interactions were validated by EMSA and other methods. For most of the candidates, we observed no RNA binding (12/19) or a rather unspecific binding (5/19). Two of the candidates, namely glutamate-5-kinase (ProB) and quinone oxidoreductase (QorA), displayed specific and previously unknown binding to distinct RNAs. We concentrated on the interaction of QorA to the mRNA of yffO , a grounded prophage gene, which could be validated by EMSA and MST. Because the physiological function of both partners is not known, the biological relevance of this interaction remains elusive. Furthermore, we found novel RNA targets for the MS2 phage coat protein that served us as control. Our results indicate that RNA binding of metabolic enzymes in procaryotes is less frequent than suggested by the results of high-throughput studies, but does occur.
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- 2023
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11. Reprogramming the Specificity of a Protein Interface by Computational and Data-Driven Design.
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Hertle R, Nazet J, Semmelmann F, Schlee S, Funke F, Merkl R, and Sterner R
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- Amino Acid Substitution, Anthranilate Synthase genetics, Anthranilate Synthase metabolism, Binding Sites, Carbon-Carbon Lyases genetics, Carbon-Carbon Lyases metabolism, Escherichia coli Proteins genetics, Escherichia coli Proteins metabolism, Molecular Docking Simulation methods, Protein Binding, Protein Interaction Mapping methods, Transaminases genetics, Transaminases metabolism, Anthranilate Synthase chemistry, Carbon-Carbon Lyases chemistry, Escherichia coli Proteins chemistry, Transaminases chemistry
- Abstract
The formation of specific protein complexes in a cell is a non-trivial problem given the co-existence of thousands of different polypeptide chains. A particularly difficult case are two glutamine amidotransferase complexes (anthranilate synthase [AS] and aminodeoxychorismate synthase [ADCS]), which are composed of homologous pairs of synthase and glutaminase subunits. We have attempted to identify discriminating interface residues of the glutaminase subunit TrpG from AS, which are responsible for its specific interaction with the synthase subunit TrpEx and prevent binding to the closely related synthase subunit PabB from ADCS. For this purpose, TrpG-specific interface residues were grafted into the glutaminase subunit PabA from ADCS by two different approaches, namely a computational and a data-driven one. Both approaches resulted in PabA variants that bound TrpEx with higher affinity than PabB. Hence, we have accomplished a reprogramming of protein-protein interaction specificity that provides insights into the evolutionary adaptation of protein interfaces., Competing Interests: Declaration of Interests The authors declare no competing interests., (Copyright © 2020 Elsevier Ltd. All rights reserved.)
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- 2021
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12. Thoracic Ultrasound for Immediate Exclusion of Pneumothorax after Interventional Bronchoscopy.
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Eisenmann S, Winantea J, Karpf-Wissel R, Funke F, Stenzel E, Taube C, and Darwiche K
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Background: Pneumothorax is a common side effect in interventional pulmonology. The ideal moment for detection with chest X-ray or ultrasound has not yet been defined. Earlier studies demonstrated the utility of performing these tests with a certain delay, which always results in a potentially dangerous gap., Methods: We prospectively enrolled patients with pulmonary interventions at increased risk of pneumothorax. Thoracic ultrasound was performed immediately after the intervention and at the moment of chest X-ray with a delay up to two hours., Results: Overall, we detected four pneumothoraxes in 115 procedures. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 75%, 100%, 100%, 99%, 99% for ultrasound and 75%, 90%, 21%, 99% und 89% for chest X-ray respectively. All pneumothoraces requiring chest tube were sufficiently detected by both methods., Conclusion: Thoracic ultrasound when performed immediately can more accurately exclude pneumothorax after interventional bronchoscopy when compared to chest X-ray. Further ultrasound examinations are unnecessary.
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- 2020
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13. Correlating physical properties of aqueous-organic solvent systems and stationary phase retention in a centrifugal partition chromatograph in descending mode.
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Fromme A, Funke F, Merz J, and Schembecker G
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- Centrifugation, Viscosity, Chromatography, Liquid, Solvents chemistry, Water chemistry
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The performance of the Centrifugal Partition Chromatography (CPC) as a liquid-liquid chromatographic technique depends strongly on the two-phase solvent system used. Thereby the individual influence of the retention of the stationary phase, the coalescence, and the dispersion of the mobile phase in the chambers must be understood to select appropriate solvent systems and reach high separation efficiencies. In this study, an optical measurement system was used to investigate the influence of the physical properties of the Arizona solvent systems on the stationary phase retention in descending mode. Therefore, physical properties like density, viscosity, and interfacial tension were measured as well as the stationary phase retention. Using dimensionless numbers, a correlation between the stationary phase retention and the influencing parameters could be determined. The correlation was validated using data from the literature. Additionally, the solvent systems were modified by additives to identify the validity of the correlation. It was proven that the dimensionless numbers Capillary number (Ca) and Morton number (Mo) can be used to predict the stationary phase retention of other liquid-liquid solvent systems as well as for different operating conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Published
- 2020
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14. Integration of Bronchoscopic Transesophageal Ultrasound Examination of the Left Adrenal Gland into Routine Lung Cancer Staging Workup: A Prospective Trial.
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Darwiche K, Becker J, Winantea J, Karpf-Wissel R, Funke F, Stenzel E, Hautzel H, Hager T, and Eisenmann S
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- Adenocarcinoma of Lung diagnostic imaging, Adenocarcinoma of Lung secondary, Adrenal Gland Neoplasms diagnostic imaging, Adrenal Glands diagnostic imaging, Adult, Aged, Aged, 80 and over, Bronchoscopes, Carcinoma, Non-Small-Cell Lung diagnostic imaging, Carcinoma, Squamous Cell diagnostic imaging, Carcinoma, Squamous Cell secondary, Endosonography, Female, Humans, Learning Curve, Male, Middle Aged, Neoplasm Staging, Small Cell Lung Carcinoma diagnostic imaging, Small Cell Lung Carcinoma secondary, Adrenal Gland Neoplasms secondary, Adrenal Glands pathology, Bronchoscopy methods, Carcinoma, Non-Small-Cell Lung secondary, Endoscopic Ultrasound-Guided Fine Needle Aspiration methods, Esophagoscopy methods, Lung Neoplasms pathology
- Abstract
Background: Endobronchial ultrasound (EBUS) with transbronchial needle aspiration increases the diagnostic yield of lung cancer staging. The left adrenal gland (LAG) is a common site for lung cancer metastasis. The modality of transesophageal examination with an EBUS bronchoscope (EUS-B) routinely for LAG has not been assessed., Objective: The aim of this study was to prospectively assess if evaluation and tissue sampling of the LAG could routinely be implemented in an EBUS procedure., Methods: Patients referred for EBUS between March and August 2017 had assessment of the LAG via EUS-B. Fine-needle aspiration (FNA) was performed in cases with a suspicious LAG. The detection rate, procedure time, and learning curve of four experienced EBUS-bronchoscopists was assessed, plus the diagnostic accuracy and complication rate of FNA., Results: In total, 313 consecutive patients were included. The overall LAG detection rate was 87.5%. After the initial learning curve, the detection rate for all four bronchoscopists was >93%. The detection rate did not correlate with any patient characteristics. EUS-B-FNA revealed nine LAG metastases, with a sensitivity, specificity, and accuracy of 75%, 100%, and 99%, respectively. The mean EUS-B operation time was 194.4 s, with 594.8 s for FNA. There were no FNA-associated complications., Conclusions: Evaluation of the LAG with EUS-B could routinely be included in an EBUS procedure if necessary. A high detection rate can be achieved after an initial learning period. FNA of the LAG was feasible and safe. EUS-B of the LAG could be integrated into the usual EBUS/EUS-B procedure in lung cancer staging workup., (© 2019 S. Karger AG, Basel.)
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- 2020
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15. Predictive value of Chartis measurement for lung function improvements in bronchoscopic lung volume reduction.
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Wienker J, Karpf-Wissel R, Funke F, Taube C, Wälscher J, Winantea J, Maier S, Mardanzai K, and Darwiche K
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- Aged, Female, Forced Expiratory Volume, Humans, Lung diagnostic imaging, Lung physiopathology, Lung Volume Measurements, Male, Middle Aged, Pulmonary Disease, Chronic Obstructive diagnosis, Pulmonary Disease, Chronic Obstructive physiopathology, Pulmonary Emphysema diagnosis, Pulmonary Emphysema physiopathology, Recovery of Function, Retrospective Studies, Treatment Outcome, Vital Capacity, Bronchoscopy adverse effects, Bronchoscopy instrumentation, Lung surgery, Pulmonary Disease, Chronic Obstructive surgery, Pulmonary Emphysema surgery
- Abstract
Background: Bronchoscopic lung volume reduction (BLVR) via valve implantation can be achieved by targeting severely hyperinflated and emphysematously destructed lung areas in patients with chronic obstructive lung disease. Lack of collateral ventilation (CV) is important for good outcomes with BLVR. CV can be measured using the catheter-based Chartis system. The aim of this study was to evaluate the correlation between total exhaled volume drained from the target lobe measured by Chartis and clinical outcomes after BLVR in CV-negative patients., Methods: From January 2016 to March 2019, 60 patients were included in this retrospective single-center analysis. Drained volume (TVol) measured by Chartis was recorded and compared with lung function and physical performance parameters. Outcome variables included the percentage change in lung function [forced expiratory volume in 1 s (FEV
1 ), residual volume (RV), and inspiratory vital capacity (IVC)]. Secondary outcomes were the degree of target lobe volume reduction (TLVR), change in 6-min walk distance (6MWD), and change in chronic obstructive pulmonary disease (COPD) assessment test (CAT) score., Results: Drained volume correlated significantly with post-BLVR change in FEV1 ( r = 0.663), IVC ( r = 0.611), RV ( r = -0.368), and TLVR ( r = 0.635) (all p < 0.05). In a priori -defined patient subgroups based on drained volume [<100 ml ( n = 19), 100-400 ml ( n = 33), and >400 ml ( n = 8)]; mean changes in FEV1 were 2.6%, 17.4%, and 51.3%; in RV were -3.9%, -10.6%, and -23.8%; in IVC were -4.0%, 10.6%, and 62.4%; and in TLVR were 525 ml (39%), 1375 ml (73%) and 1760 ml (100%), respectively. There were no significant correlations between absolute and percentage changes in 6MWD and the CAT score. Lung volume reduction was diagnosed in 32 (53%) cases., Conclusion: Drained volume measured by the Chartis system correlated with functional improvement in CV-negative patients undergoing BLVR. The reviews of this paper are available via the supplemental material section.- Published
- 2020
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16. Five Lessons from COVID-19 for Advancing Climate Change Mitigation.
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Klenert D, Funke F, Mattauch L, and O'Callaghan B
- Abstract
The nexus of COVID-19 and climate change has so far brought attention to short-term greenhouse gas (GHG) emissions reductions, public health responses, and clean recovery stimulus packages. We take a more holistic approach, making five broad comparisons between the crises with five associated lessons for climate change mitigation policy. First, delay is costly. Second, policy design must overcome biases to human judgment. Third, inequality can be exacerbated without timely action. Fourth, global problems require multiple forms of international cooperation. Fifth, transparency of normative positions is needed to navigate value judgments at the science-policy interface. Learning from policy challenges during the COVID-19 crisis could enhance efforts to reduce GHG emissions and prepare humanity for future crises., (© Springer Nature B.V. 2020.)
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- 2020
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17. Bronchial Thermoplasty Including the Middle Lobe Bronchus Significantly Improves Lung Function and Quality of Life in Patients Suffering from Severe Asthma.
- Author
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Eisenmann S, Schütte W, Funke F, Oezkan F, Islam S, and Darwiche K
- Subjects
- Adrenal Cortex Hormones administration & dosage, Adult, Asthma diagnosis, Asthma drug therapy, Asthma physiopathology, Bronchi drug effects, Bronchi physiopathology, Bronchoscopy, Female, Forced Expiratory Volume, Germany, Humans, Male, Middle Aged, Recovery of Function, Retrospective Studies, Severity of Illness Index, Time Factors, Treatment Outcome, Asthma surgery, Bronchi surgery, Bronchial Thermoplasty adverse effects, Bronchoconstriction drug effects, Quality of Life
- Abstract
Purpose: Bronchial Thermoplasty (BT) is indicated in patients suffering from severe and symptomatic bronchial asthma despite maximal medical therapy. However, treatment of the right middle lobe (RML) bronchus is currently not recommended. The aim of this study was to investigate the safety and efficacy of BT if the RML bronchus is included., Methods: BT was performed in 17 consecutive patients, quality of life and pulmonary function were characterized before and 90 days after BT completion. Furthermore, we performed a clean-up bronchoscopy following every BT. This study was approved by the IRB of the University of Essen (No. 17-7356 BO) and registered as a retrospective observational study at the German Clinical Trials Registry (No. DRKS 00011550)., Results: The median baseline values of FEV1 and Asthma Questionnaire of Life Quality (AQLQ) were 1.33 l (0.91; 1.73) and 3.01 (2.76; 3.61), respectively, and significantly improved 90 days after treatment with FEV 1 at 1.75 l (p-value 0.002) and AQLQ 3.8 (p-value < 0.05). Also the amount of oral corticosteroid necessity decreased significantly. No severe adverse events occurred due to the procedure. Clean-up bronchoscopies-when performed-revealed significant fibrinous exudation after every BT procedure., Conclusion: BT including the RML bronchus is feasible. Functionally limited patients with severe asthma could potentially profit. Due to the relevant fibrinous exudation, BT should be followed by clean-up bronchoscopy, not only after RML treatment.
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- 2019
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18. Towards Individualized Tracheobronchial Stents: Technical, Practical and Legal Considerations.
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Freitag L, Gördes M, Zarogoulidis P, Darwiche K, Franzen D, Funke F, Hohenforst-Schmidt W, and Dutau H
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- Humans, Liability, Legal, Pulmonary Medicine legislation & jurisprudence, Silicones, Lung Diseases, Obstructive therapy, Precision Medicine trends, Printing, Three-Dimensional, Pulmonary Medicine trends, Stents
- Abstract
Stent placement has been established as a standard procedure for treating airway obstructions. Other indications are localized malacias and fistulas. Though many different stents with various diameters and lengths are available, the shapes are hardly ever ideal because of the distorted anatomy in patients with diseased airways. There are technical and legal limitations for customizing purchased airway stents. Individually tailored stents would be preferable. New techniques of additive manufacturing such as 3D printing make it possible to produce optimized stents for a particular patient. Using CT data and bronchoscopic images, stents can be constructed that match a particular anatomical situation and apply the optimized expansion force. We give an overview of the currently available manufacturing techniques for polymeric stents and report about our own experience. Direct on-site printing of polyurethane stents in a hospital and printing individual extrusion molds for silicone stents in a certified cleanroom are both feasible. Furthermore, there are promising attempts of combining mechanically customized stents with surface modifications, drug-eluting features, biodegradability, and time-dependent adaptation (4D printing). Truly optimized airway stents with the potential of solving the well-known stent problems such as granulation tissue formation, remodeling, mucostasis, and infections are in reach. The technical hurdles are probably easier to overcome than the legal constraints. The legal situations are discussed from a physician's and a manufacturer's perspective., (© 2017 S. Karger AG, Basel.)
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- 2017
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19. The Effect of Chronic Kidney Disease on Mortality with Cardiac Resynchronization Therapy.
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Daly DD Jr, Maran A, Hyer JM, Funke F, Waring A, Cuoco FA, Sturdivant JL, Leman RB, and Gold MR
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- Aged, Causality, Cohort Studies, Comorbidity, Female, Humans, Incidence, Male, Middle Aged, Retrospective Studies, Risk Factors, Survival Rate, Treatment Outcome, United States epidemiology, Cardiac Resynchronization Therapy mortality, Defibrillators, Implantable statistics & numerical data, Heart Failure mortality, Heart Failure prevention & control, Renal Insufficiency, Chronic mortality
- Abstract
Background: Cardiac resynchronization therapy (CRT) improves functional status, reduces heart failure hospitalizations, and decreases mortality. Several comorbidities including renal function affect outcomes with CRT. However, moderate to severe chronic kidney disease (CKD) was an exclusion criterion in the large randomized control trials., Objective: To evaluate the association of renal function on survival following CRT implantation., Methods: This was a retrospective analysis of 432 consecutive patients implanted with an implantable cardioverter defibrillator with CRT (CRT-D). The primary end point was defined as death by any cause, and it was determined using hospital records and the U.S. Social Security Death Index. A Kaplan-Meier analysis was performed separating renal dysfunction into renal stage based on glomerular filtration rate. Multivariate analysis was performed to assess the clinical predictors of mortality., Results: Patients were followed for up to 12 years with a mean follow-up time of 4.3 ± 3.2 years. A total of 164 patients (39.3%) died over the course of the study. Patients with normal and mild renal diseases (Stages 1 and 2) had improved survival compared with those with moderate-, severe-, or end-stage (Stages 3-5) renal disease. This effect remained statistically significant after multivariate analysis. The estimated 5-year mortality was 36.3% for stage 1, 33.4% for stage 2, 40.6% for stage 3, and 62.1% for stage 4/5 kidney disease (P = 0.004 by log-rank test)., Conclusion: CKD is a strong and an independent predictor of long-term mortality among patients undergoing CRT-D implantation., (© 2016 Wiley Periodicals, Inc.)
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- 2016
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20. Using endobronchial valves to reduce irradiation portals in lung cancer: a case report.
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Funke F, Gauler T, Freitag L, and Pöttgen C
- Subjects
- Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung surgery, Chemoradiotherapy, Humans, Lung Neoplasms drug therapy, Lung Neoplasms surgery, Lymphatic Metastasis, Male, Middle Aged, Prostheses and Implants, Bronchi surgery, Carcinoma, Non-Small-Cell Lung radiotherapy, Lung Neoplasms radiotherapy
- Published
- 2014
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21. Facing the dreaded: does mindfulness facilitate coping with distressing experiences? A moderator analysis.
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Bergomi C, Ströhle G, Michalak J, Funke F, and Berking M
- Subjects
- Adolescent, Adult, Affect, Aged, Aged, 80 and over, Female, Humans, Male, Mental Health, Middle Aged, Models, Psychological, Adaptation, Psychological, Life Change Events, Mindfulness, Stress, Psychological psychology
- Abstract
Increasing evidence shows that mindfulness is positively related to mental health; however, the nature of this relationship is not fully understood. The current study used structural equation modeling to investigate the hypothesis that mindfulness moderates the association between the occurrence of unavoidable distressing experiences (UDE) and mental health. Participants from a community sample (N = 376) completed the Freiburg Mindfulness Inventory, the Positive and Negative Affect Scale, the Brief Symptom Inventory, the Inventory of Approach and Avoidance Motivation, and the Incongruence Scale. Results indicated that mindfulness moderated the association between unavoidable distressing events and psychopathological symptoms/negative affect. Thus, mindfulness may contribute to enhance the ability to cope with UDE and thus mitigate the detrimental effects of these experiences on mental health.
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- 2013
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22. Ratiometric high-resolution imaging of JC-1 fluorescence reveals the subcellular heterogeneity of astrocytic mitochondria.
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Keil VC, Funke F, Zeug A, Schild D, and Müller M
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- Aniline Compounds, Animals, Astrocytes metabolism, Astrocytes ultrastructure, Calcium metabolism, Cells, Cultured, Hippocampus ultrastructure, Microscopy, Fluorescence, Multiphoton, Mitochondria ultrastructure, Rats, Rats, Sprague-Dawley, Xanthenes, Benzimidazoles, Carbocyanines, Membrane Potential, Mitochondrial physiology, Mitochondria metabolism
- Abstract
Using the mitochondrial potential (ΔΨ(m)) marker JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide) and high-resolution imaging, we functionally analyzed mitochondria in cultured rat hippocampal astrocytes. Ratiometric detection of JC-1 fluorescence identified mitochondria with high and low ΔΨ(m). Mitochondrial density was highest in the perinuclear region, whereas ΔΨ(m) tended to be higher in peripheral mitochondria. Spontaneous ΔΨ(m) fluctuations, representing episodes of increased energization, appeared in individual mitochondria or synchronized in mitochondrial clusters. They continued upon withdrawal of extracellular Ca(2+), but were antagonized by dantrolene or 2-aminoethoxydiphenylborate (2-APB). Fluo-3 imaging revealed local cytosolic Ca(2+) transients with similar kinetics that also were depressed by dantrolene and 2-APB. Massive cellular Ca(2+) load or metabolic impairment abolished ΔΨ(m) fluctuations, occasionally evoking heterogeneous mitochondrial depolarizations. The detected diversity and ΔΨ(m) heterogeneity of mitochondria confirms that even in less structurally polarized cells, such as astrocytes, specialized mitochondrial subpopulations coexist. We conclude that ΔΨ(m) fluctuations are an indication of mitochondrial viability and are triggered by local Ca(2+) release from the endoplasmic reticulum. This spatially confined organelle crosstalk contributes to the functional heterogeneity of mitochondria and may serve to adapt the metabolism of glial cells to the activity and metabolic demand of complex neuronal networks. The established ratiometric JC-1 imaging-especially combined with two-photon microscopy-enables quantitative functional analyses of individual mitochondria as well as the comparison of mitochondrial heterogeneity in different preparations and/or treatment conditions.
- Published
- 2011
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23. Altered responses of MeCP2-deficient mouse brain stem to severe hypoxia.
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Kron M, Zimmermann JL, Dutschmann M, Funke F, and Müller M
- Subjects
- 8-Hydroxy-2-(di-n-propylamino)tetralin pharmacology, Analysis of Variance, Animals, Animals, Newborn, Brain Stem pathology, Cortical Spreading Depression drug effects, Electric Stimulation, Extracellular Fluid metabolism, Hypoxia genetics, In Vitro Techniques, Male, Mice, Mice, Knockout, Neural Pathways physiology, Potassium metabolism, Reaction Time drug effects, Reaction Time genetics, Respiratory Center drug effects, Respiratory Center physiology, Serotonin Receptor Agonists pharmacology, Solitary Nucleus physiopathology, Time Factors, Trigeminal Nucleus, Spinal physiopathology, Brain Stem physiopathology, Cortical Spreading Depression genetics, Hypoxia pathology, Methyl-CpG-Binding Protein 2 deficiency
- Abstract
Rett syndrome (RTT) patients suffer from respiratory arrhythmias with frequent apneas causing intermittent hypoxia. In a RTT mouse model (methyl-CpG-binding protein 2-deficient mice; Mecp2(-/y)) we recently discovered an enhanced hippocampal susceptibility to hypoxia and hypoxia-induced spreading depression (HSD). In the present study we investigated whether this also applies to infant Mecp2(-/y) brain stem, which could become life-threatening due to failure of cardiorespiratory control. HSD most reliably occurred in the nucleus of the solitary tract (NTS) and the spinal trigeminal nucleus (Sp5). HSD susceptibility of the Mecp2(-/y) NTS and Sp5 was increased on 8 mM K(+)-mediated conditioning. 5-HT(1A) receptor stimulation with 8-hydroxy-2-(di-propylamino)tetralin (8-OH-DPAT) postponed HSD by up to 40%, mediating genotype-independent protection. The deleterious impact of HSD on in vitro respiration became obvious in rhythmically active slices, where HSD propagation into the pre-Bötzinger complex (pre-BötC) immediately arrested the respiratory rhythm. Compared with wild-type, the Mecp2(-/y) pre-BötC was invaded less frequently by HSD, but if so, HSD occurred earlier. On reoxygenation, in vitro rhythms reappeared with increased frequency, which was less pronounced in Mecp2(-/y) slices. 8-OH-DPAT increased respiratory frequency but failed to postpone HSD in the pre-BötC. Repetitive hypoxia facilitated posthypoxic recovery only if HSD occurred. In 57% of Mecp2(-/y) slices, however, HSD spared the pre-BötC. Although this occasionally promoted residual hypoxic respiratory activity ("gasping"), it also prolonged the posthypoxic recovery, and thus the absence of central inspiratory drive, which in vivo would lengthen respiratory arrest. In view of the breathing disorders in RTTs, the increased hypoxia susceptibility of MeCP2-deficient brain stem potentially contributes to life-threatening disturbances of cardiorespiratory control.
- Published
- 2011
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24. Dynamic, semi-quantitative imaging of intracellular ROS levels and redox status in rat hippocampal neurons.
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Funke F, Gerich FJ, and Müller M
- Subjects
- Animals, Cells, Cultured, Coloring Agents, Female, Male, Organ Culture Techniques, Oxidation-Reduction, Rats, Reactive Oxygen Species metabolism, Green Fluorescent Proteins, Hippocampus metabolism, Microscopy, Fluorescence methods, Neurons metabolism, Reactive Oxygen Species analysis
- Abstract
The cellular redox status is determined by various extra- and intracellular factors, and contributes to cytosolic signaling and oxidative stress. Especially mitochondria modulate the cytosolic redox status by oxidizing NADH and FADH(2) and generating reactive oxygen species (ROS). Whereas cellular NADH and FAD levels are reliably detectable as autofluorescence, quantifying cellular ROS production is more demanding, because the various redox-sensitive dyes share major disadvantages including irreversible oxidation, autooxidation and photosensitivity. As an alternative, we took advantage of a genetically engineered redox-sensitive green fluorescent protein (roGFP1), carefully evaluated its response properties, and succeeded to monitor ROS dynamics in cultured rat hippocampal neurons and organotypic slices. The ratiometric properties and reversible oxidation/reduction of roGFP1 enable reliable, semi-quantitative analyses of cytosolic ROS levels and redox status. Cytosolically expressed roGFP1 readily responded to hydrogen peroxide, superoxide and hydroxyl radicals, and was only negligibly affected by intracellular pH or Cl(-) content. Furthermore, roGFP1 was well suited for two-photon excitation, reliably detected changes in endogenous ROS production during impaired mitochondrial respiration or neuronal stimulation, and was even capable of visualizing perimitochondrial ROS microdomains. Modulation of cellular scavenging systems confirmed the functional integration of roGFP1 into the cellular ROS and redox balance. We conclude that roGFP1 is well suited for dynamic, compartment specific, subcellular analyses even in complex neuronal networks. The ability to correlate dynamic changes in cellular ROS levels with mitochondrial metabolism and neuronal network activity is a promising step towards a detailed mechanistic understanding of redox- and ROS-mediated signaling in normal and diseased brain function., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2011
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25. Majority members' acculturation goals as predictors and effects of attitudes and behaviours towards migrants.
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Geschke D, Mummendey A, Kessler T, and Funke F
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Cultural Characteristics, Female, Germany, Humans, Longitudinal Studies, Male, Middle Aged, Prejudice, Social Change, Social Conformity, Social Identification, Young Adult, Acculturation, Attitude, Emigrants and Immigrants psychology, Goals, Refugees psychology, Social Behavior
- Abstract
Migration causes permanent processes of acculturation involving migrants but also members of mainstream society. A longitudinal field study with 70 German majority members investigated how their acculturation goals causally related to their attitudes and behaviours towards migrants. We distinguished acculturation goals concerning the migrants' culture(s) (what migrants should do) and acculturation goals concerning the usually neglected own changing mainstream culture. Both were conceived along the two dimensions of 'culture maintenance' and 'culture adoption'. Cross-sectionally we found many strong links between acculturation goals and attitudes and behaviours towards migrants, only some of which held longitudinally. As hypothesized there was no clear one-sided causal direction. As many causal links lead from acculturation goals to attitudes and behaviours, as in the opposite direction. Majority members' German culture acculturation goals proved especially valuable, because they determined attitudes and behaviour towards migrants most strongly.
- Published
- 2010
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26. H(2)O(2)-mediated modulation of cytosolic signaling and organelle function in rat hippocampus.
- Author
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Gerich FJ, Funke F, Hildebrandt B, Fasshauer M, and Müller M
- Subjects
- Adenosine Triphosphate metabolism, Animals, Axonal Transport drug effects, Calcium Channel Blockers pharmacology, Calcium Signaling drug effects, Cells, Cultured, Cytosol drug effects, Endoplasmic Reticulum drug effects, Endoplasmic Reticulum metabolism, Flavin-Adenine Dinucleotide metabolism, Hippocampus drug effects, Hydrogen Peroxide pharmacology, Inositol 1,4,5-Trisphosphate Receptors antagonists & inhibitors, Kinetics, Male, Membrane Potential, Mitochondrial drug effects, Mitochondria drug effects, Mitochondria metabolism, Movement drug effects, NAD metabolism, Neurons drug effects, Organelles drug effects, Oxidation-Reduction drug effects, Purinergic P2 Receptor Agonists, Rats, Rats, Sprague-Dawley, Reactive Oxygen Species metabolism, Receptors, Purinergic P2, Receptors, Purinergic P2Y12, Calcium Signaling physiology, Cytosol metabolism, Hippocampus cytology, Hippocampus metabolism, Hydrogen Peroxide metabolism, Neurons physiology, Organelles physiology
- Abstract
Reactive oxygen species (ROS) released from (dys-)functioning mitochondria contribute to normal and pathophysiological cellular signaling by modulating cytosolic redox state and redox-sensitive proteins. To identify putative redox targets involved in such signaling, we exposed hippocampal neurons to hydrogen peroxide (H(2)O(2)). Redox-sensitive dyes indicated that externally applied H(2)O(2) may oxidize intracellular targets in cell cultures and acute tissue slices. In cultured neurons, H(2)O(2) (EC(50) 118 microM) induced an intracellular Ca(2+) rise which could still be evoked upon Ca(2+) withdrawal and mitochondrial uncoupling. It was, however, antagonized by thapsigargin, dantrolene, 2-aminoethoxydiphenyl borate, and high levels of ryanodine, which identifies the endoplasmic reticulum (ER) as the intracellular Ca(2+) store involved. Intracellular accumulation of endogenously generated H(2)O(2)-provoked by inhibiting glutathione peroxidase-also released Ca(2+) from the ER, as did extracellular generation of superoxide. Phospholipase C (PLC)-mediated metabotropic signaling was depressed in the presence of H(2)O(2), but cytosolic cyclic adenosine-5'-monophosphate (cAMP) levels were not affected. H(2)O(2) (0.2-5 mM) moderately depolarized mitochondria, halted their intracellular trafficking in a Ca(2+)- and cAMP-independent manner, and directly oxidized cellular nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH(2)). In part, the mitochondrial depolarization reflects uptake of Ca(2+) previously released from the ER. We conclude that H(2)O(2) releases Ca(2+) from the ER via both ryanodine and inositol trisphosphate receptors. Mitochondrial function is not markedly impaired even by millimolar concentrations of H(2)O(2). Such modulation of Ca(2+) signaling and organelle interaction by ROS affects the efficacy of PLC-mediated metabotropic signaling and may contribute to the adjustment of neuronal function to redox conditions and metabolic supply.
- Published
- 2009
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27. Infant brain stem is prone to the generation of spreading depression during severe hypoxia.
- Author
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Funke F, Kron M, Dutschmann M, and Müller M
- Subjects
- Age Factors, Animals, Animals, Newborn, Brain Stem growth & development, Cortical Spreading Depression drug effects, Dose-Response Relationship, Drug, Electric Stimulation methods, Extracellular Fluid drug effects, Extracellular Fluid physiology, Female, Hypoglossal Nerve drug effects, Hypoglossal Nerve physiopathology, Hypoxia physiopathology, In Vitro Techniques, Male, Potassium pharmacology, Rats, Rats, Sprague-Dawley, Reaction Time drug effects, Reaction Time physiology, Sensory Thresholds physiology, Solitary Nucleus drug effects, Solitary Nucleus physiopathology, Trigeminal Nucleus, Spinal drug effects, Trigeminal Nucleus, Spinal physiopathology, Brain Stem physiopathology, Cortical Spreading Depression physiology, Hypoxia pathology
- Abstract
Spreading depression (SD) resembles a concerted, massive neuronal/glial depolarization propagating within the gray matter. Being associated with cerebropathology, such as cerebral ischemia or hemorrhage, epileptic seizures, and migraine, it is well studied in cortex and hippocampus. We have now analyzed the susceptibility of rat brain stem to hypoxia-induced spreading depression-like depolarization (HSD), which could critically interfere with cardiorespiratory control. In rat brain stem slices, severe hypoxia (oxygen withdrawal) triggered HSD within minutes. The sudden extracellular DC potential shift of approximately -20 mV showed the typical profile known from other brain regions and was accompanied by an intrinsic optical signal (IOS). Spatiotemporal IOS analysis revealed that in infant brain stem, HSD was preferably ignited within the spinal trigeminal nucleus and then mostly spread out medially, invading the hypoglossal nucleus, the nucleus of the solitary tract (NTS), and the ventral respiratory group (VRG). The neuronal hypoxic depolarizations underlying the generation of HSD were massive, but incomplete. The propagation velocity of HSD and the associated extracellular K(+) rise were also less marked than in other brain regions. In adult brain stem, HSD was mostly confined to the NTS and its occurrence was facilitated by hypotonic solutions, but not by glial poisoning or block of GABAergic and glycinergic synapses. In conclusion, brain stem tissue reliably generates propagating HSD episodes, which may be of interest for basilar-type migraine and brain stem infarcts. The preferred occurrence of HSD in the infant brain stem and its propagation into the VRG may be of importance for neonatal brain stem pathology such as sudden infant death syndrome.
- Published
- 2009
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28. Does contact reduce prejudice or does prejudice reduce contact? A longitudinal test of the contact hypothesis among majority and minority groups in three European countries.
- Author
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Binder J, Zagefka H, Brown R, Funke F, Kessler T, Mummendey A, Maquil A, Demoulin S, and Leyens JP
- Subjects
- Analysis of Variance, Anxiety, Belgium, Emotions physiology, England, Female, Germany, Humans, Longitudinal Studies, Male, Social Behavior, Group Processes, Interpersonal Relations, Minority Groups statistics & numerical data, Prejudice, Psychological Distance, Social Perception
- Abstract
A widely researched panacea for reducing intergroup prejudice is the contact hypothesis. However, few longitudinal studies can shed light on the direction of causal processes: from contact to prejudice reduction (contact effects) or from prejudice to contact reduction (prejudice effects). The authors conducted a longitudinal field survey in Germany, Belgium, and England with school students. The sample comprised members of both ethnic minorities (n = 512) and ethnic majorities (n = 1,143). Path analyses yielded both lagged contact effects and prejudice effects: Contact reduced prejudice, but prejudice also reduced contact. Furthermore, contact effects were negligible for minority members. These effects were obtained for 2 indicators of prejudice: negative intergroup emotions and desire for social distance. For both majority and minority members, contact effects on negative emotions were stronger when outgroup contacts were perceived as being typical of their group. Contact effects were also mediated by intergroup anxiety. This mediating mechanism was impaired for minority members because of a weakened effect of anxiety on desire for social distance. Theoretical and practical implications of these findings are discussed., ((c) 2009 APA, all rights reserved.)
- Published
- 2009
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29. Reconfiguration of respiratory-related population activity in a rostrally tilted transversal slice preparation following blockade of inhibitory neurotransmission in neonatal rats.
- Author
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Funke F, Müller M, and Dutschmann M
- Subjects
- Animals, Animals, Newborn, Bicuculline pharmacology, Electric Stimulation, Electrophysiology, Female, GABA Antagonists pharmacology, Image Processing, Computer-Assisted, In Vitro Techniques, Male, Neural Pathways cytology, Neurons physiology, Poisons pharmacology, Rats, Strychnine pharmacology, Neural Pathways drug effects, Neural Pathways physiology, Respiratory Mechanics physiology, Synaptic Transmission drug effects, Synaptic Transmission physiology
- Abstract
Recent studies showed that respiratory rhythm generation depends on oscillators located in the pre-Bötzinger complex (pre-BötC) and the parafacial respiratory group (pFRG). To study inhibitory synaptic interactions between these two oscillators, we developed a rostrally tilted transversal slice preparation, which preserves these regions. The onset of rhythmic mass activity in the retrotrapezoid nucleus (RTN)/pFRG preceded that of the pre-BötC. Blockade of glycinergic and gamma-aminobutyric acidic inhibition synchronized pre-BötC and RTN/pFRG activity and significantly increased pre-BötC burst frequency, amplitude, and duration. Population imaging revealed recruitment of inspiratory-like neurones, while expiratory-like neurones lost their phasic activity. The reconfiguration after disinhibition reveals: (1) synaptic inhibition of the pre-BötC arising from the RTN/pFRG, (2) excitatory drive from the RTN/pFRG that triggers the pre-BötC burst. Our findings support the view that these synaptic interactions in vitro relate to the initiation of the inspiratory phase or to the steering of the expiratory-inspiratory phase transition in vivo.
- Published
- 2008
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30. Oxidation of cofilin mediates T cell hyporesponsiveness under oxidative stress conditions.
- Author
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Klemke M, Wabnitz GH, Funke F, Funk B, Kirchgessner H, and Samstag Y
- Subjects
- Actin Depolymerizing Factors chemistry, CD28 Antigens immunology, CD3 Complex immunology, Chemotaxis, Leukocyte, Humans, Hydrogen Peroxide metabolism, Lim Kinases metabolism, Neutrophil Activation, Neutrophils metabolism, Oxidation-Reduction, Phosphorylation, T-Lymphocytes metabolism, Actin Depolymerizing Factors metabolism, Actins metabolism, Lymphocyte Activation, Neutrophils immunology, Oxidative Stress, T-Lymphocytes immunology
- Abstract
Oxidative stress leads to impaired T cell activation. A central integrator of T cell activation is the actin-remodelling protein cofilin. Cofilin is activated through dephosphorylation at Ser3. Activated cofilin enables actin dynamics through severing and depolymerization of F-actin. Binding of cofilin to actin is required for formation of the immune synapse and T cell activation. Here, we showed that oxidatively stressed human T cells were impaired in chemotaxis- and costimulation-induced F-actin modulation. Although cofilin was dephosphorylated, steady-state F-actin levels increased under oxidative stress conditions. Mass spectrometry revealed that cofilin itself was a target for oxidation. Cofilin oxidation induced formation of an intramolecular disulfide bridge and loss of its Ser3 phosphorylation. Importantly, dephosphorylated oxidized cofilin, although still able to bind to F-actin, did not mediate F-actin depolymerization. Impairing actin dynamics through oxidation of cofilin provides a molecular explanation for the T cell hyporesponsiveness caused by oxidative stress.
- Published
- 2008
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31. Interval-level measurement with visual analogue scales in Internet-based research: VAS Generator.
- Author
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Reips UD and Funke F
- Subjects
- Humans, Internet instrumentation, Photic Stimulation instrumentation, Research instrumentation, Surveys and Questionnaires
- Abstract
The present article describes VAS Generator (www.vasgenerator.net), a free Web service for creating a wide range of visual analogue scales that can be used as measurement devices in Web surveys and Web experimentation, as well as for local computerized assessment. A step-by-step example for creating and implementing a visual analogue scale with visual feedback is given. VAS Generator and the scales it generates work independently of platforms and use the underlying languages HTML and JavaScript. Results from a validation study with 355 participants are reported and show that the scales generated with VAS Generator approximate an interval-scale level. In light of previous research on visual analogue versus categorical (e.g., radio button) scales in Internet-based research, we conclude that categorical scales only reach ordinal-scale level, and thus visual analogue scales are to be preferred whenever possible.
- Published
- 2008
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32. Imaging of respiratory-related population activity with single-cell resolution.
- Author
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Funke F, Dutschmann M, and Müller M
- Subjects
- Aniline Compounds pharmacokinetics, Animals, Animals, Newborn, Calcium metabolism, Electrophysiology, Exhalation physiology, Fluorescence, Fluorescent Dyes pharmacokinetics, In Vitro Techniques, Inhalation physiology, Medulla Oblongata metabolism, Nerve Net cytology, Nerve Net physiology, Neurons metabolism, Rats, Rats, Sprague-Dawley, Xanthenes pharmacokinetics, Medulla Oblongata cytology, Medulla Oblongata physiology, Microscopy, Fluorescence, Neurons cytology, Respiratory Mechanics physiology
- Abstract
The pre-Bötzinger complex (PBC) in the rostral ventrolateral medulla contains a kernel involved in respiratory rhythm generation. So far, its respiratory activity has been analyzed predominantly by electrophysiological approaches. Recent advances in fluorescence imaging now allow for the visualization of neuronal population activity in rhythmogenic networks. In the respiratory network, voltage-sensitive dyes have been used mainly, so far, but their low sensitivity prevents an analysis of activity patterns of single neurons during rhythmogenesis. We now have succeeded in using more sensitive Ca(2+) imaging to study respiratory neurons in rhythmically active brain stem slices of neonatal rats. For the visualization of neuronal activity, fluo-3 was suited best in terms of neuronal specificity, minimized background fluorescence, and response magnitude. The tissue penetration of fluo-3 was improved by hyperosmolar treatment (100 mM mannitol) during dye loading. Rhythmic population activity was imaged with single-cell resolution using a sensitive charge-coupled device camera and a x20 objective, and it was correlated with extracellularly recorded mass activity of the contralateral PBC. Correlated optical neuronal activity was obvious online in 29% of slices. Rhythmic neurons located deeper became detectable during offline image processing. Based on their activity patterns, 74% of rhythmic neurons were classified as inspiratory and 26% as expiratory neurons. Our approach is well suited to visualize and correlate the activity of several single cells with respiratory network activity. We demonstrate that neuronal synchronization and possibly even network configurations can be analyzed in a noninvasive approach with single-cell resolution and at frame rates currently not reached by most scanning-based imaging techniques.
- Published
- 2007
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33. An efficient three-step synthesis of cyclopenta[b]pyrans via 2-donor-substituted fischer ethenylcarbenechromium complexes.
- Author
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de Meijere A, Schirmer H, Stein F, Funke F, Duetsch M, Wu YT, Noltemeyer M, Belgardt T, and Knieriem B
- Abstract
A wide range of cyclopenta[b]pyrans 4 has been synthesized in a one-pot reaction by treatment of different 2-donorsubstituted ethenylcarbenechromium complexes 2 with alkynes in THF in moderate to excellent yields (41-90 % for 14 out of 25 examples). The starting materials 2 are readily available in good to excellent yields (76-99 % for 25 out of 36 examples) by Michael addition of amines, alcohols and thiols, respectively, to the corresponding alkynylcarbenechromium complexes 1. Due to their 10 pi-electrons in a cross-conjugated bicyclic system, cyclopenta[b]pyrans have been termed pseudoazulenes, as they indeed have similar UV/Vis-spectroscopic properties.
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- 2005
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34. Intra-atrial ECG is not a reliable method for positioning left internal jugular vein catheters.
- Author
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Schummer W, Herrmann S, Schummer C, Funke F, Steenbeck J, Fuchs J, Uhlig T, and Reinhart K
- Subjects
- Aged, Echocardiography, Transesophageal methods, Female, Humans, Intraoperative Care methods, Jugular Veins diagnostic imaging, Male, Middle Aged, Postoperative Care methods, Prospective Studies, Radiography, Catheterization, Central Venous methods, Echocardiography methods, Ultrasonography, Interventional methods
- Abstract
Background: ECG guidance is widely used for positioning central venous catheters (CVCs) in the superior vena cava. We noticed a higher incidence of a more perpendicular angle between the catheter tip and the vessel wall after left-sided ECG-guided catheter positioning. To investigate the value of left-sided ECG guidance, we performed this prospective study., Methods: Of 114 patients, 53 were randomized to right and 61 to left internal jugular vein catheterization using a triple lumen catheter. Three methods to ascertain catheter tip position were sequentially applied in each patient, and the insertion depths (ID) obtained using each of the three methods were recorded: (i). ECG guidance with a Seldinger guide wire (ID-A); (ii). ECG guidance with saline 10% used as an exploring electrode (ID-B); (iii). from position ID-B, the catheter was rotated and advanced until all three lumina could be aspirated easily. The catheter was fixed in that position (ID-C). To determine final catheter tip position, intraoperative transoesophageal echocardiography (TOE) and a postoperative chest X-ray (CXR) were performed., Results: The depth of insertion of a catheter using the three methods varied significantly in left-sided (P<0.001), but not in right-sided catheters. Forty-eight of 57 (84%) left-sided CVCs, correctly positioned according to ECG guidance, had to be advanced further to achieve free aspiration through all three lumina. By this stage, five of the catheter tips had been positioned in the upper right atrium as demonstrated by TOE. There were 13 malpositions (23%) after left-sided insertion. In nine catheter malpositions, undetected by ECG guidance, the angle between the catheter tip and the lateral wall of the superior vena cava exceeded 40 degrees on CXR., Conclusions: Intra-atrial ECG does not detect the junction between the superior vena cava and right atrium. It is not a reliable method for confirming position of left-sided CVCs. Post-procedural CXRs are recommended for left-sided, but not right-sided CVCs.
- Published
- 2003
- Full Text
- View/download PDF
35. In vivo measurements of the internal pH of Hediste (Nereis) diversicolor (Annelida, Polychaeta) exposed to ambient sulphidic conditions using pH microelectrodes.
- Author
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Sommer S, Jahn A, Funke F, and Brenke N
- Subjects
- Animals, Electrochemistry instrumentation, Electrochemistry methods, Homeostasis, Microelectrodes, Hydrogen-Ion Concentration, Polychaeta physiology, Sulfides pharmacology
- Abstract
The effect of different ambient sulphide concentrations on the internal pH regime of Hediste (Nereis) diversicolor was studied under in vivo conditions using liquid membrane pH microelectrodes, a method which is new to marine sciences. As a case study, the hypothesis was tested whether organisms exposed to ambient sulphidic conditions are able to lower their internal pH which, in effect, would reduce sulphide influx into the animals and thus could represent an effective detoxification mechanism. It was shown that a significant lowering of the internal pH occurred within only 20 min after adding sulphide. This pH lowering appeared to be dependent on the external sulphide concentration of the ambient medium and showed a saturation beyond a threshold level of about 130 microM. It is discussed whether this sulphide-induced pH drop is an active regulatory mechanism and acts as an effective protection mechanism against sulphide during short-term exposures.
- Published
- 2000
- Full Text
- View/download PDF
36. Biomechanical behavior of human intervertebral discs subjected to long lasting axial loading.
- Author
-
Koeller W, Funke F, and Hartmann F
- Subjects
- Adolescent, Adult, Biomechanical Phenomena, Body Water physiology, Elasticity, Female, Humans, In Vitro Techniques, Lumbar Vertebrae physiology, Middle Aged, Movement, Stress, Mechanical, Viscosity, Intervertebral Disc physiology
- Abstract
48 lumbar discs were tested; the creep tests lasted between 2 and 6 hours. All discs showed the known creep behavior, i.e. a decrease of height, rate of creep and axial deformability with time. In the first minutes of a test the viscoelastic behavior quickly alters so that the disc behaves more like an elastic body. Loss of mass normally observed after creep tests is due to loss of water. Creep behavior is reproducible if a disc has sufficiently recovered, i.e. if it has regained its initial height. Creep tests on "desiccated" discs revealed that creeping is possible without loss of water and recovery is possible without absorption of water. The type of loading (static or dynamic) has hardly any influence on the biomechanical behavior. Our results indicate, that creep and recovery are chiefly due to extension and contraction of the anular fibers and not to fluid flow.
- Published
- 1984
- Full Text
- View/download PDF
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