1
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Mekacher A, Falkenberg M, Baronchelli A. The systemic impact of deplatforming on social media. PNAS Nexus 2023; 2:pgad346. [PMID: 37954163 PMCID: PMC10638500 DOI: 10.1093/pnasnexus/pgad346] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/06/2023] [Indexed: 11/14/2023]
Abstract
Deplatforming, or banning malicious accounts from social media, is a key tool for moderating online harms. However, the consequences of deplatforming for the wider social media ecosystem have been largely overlooked so far, due to the difficulty of tracking banned users. Here, we address this gap by studying the ban-induced platform migration from Twitter to Gettr. With a matched dataset of 15M Gettr posts and 12M Twitter tweets, we show that users active on both platforms post similar content as users active on Gettr but banned from Twitter, but the latter have higher retention and are 5 times more active. Our results suggest that increased Gettr use is not associated with a substantial increase in user toxicity over time. In fact, we reveal that matched users are more toxic on Twitter, where they can engage in abusive cross-ideological interactions, than Gettr. Our analysis shows that the matched cohort are ideologically aligned with the far-right, and that the ability to interact with political opponents may be part of Twitter's appeal to these users. Finally, we identify structural changes in the Gettr network preceding the 2023 Brasília insurrections, highlighting the risks that poorly regulated social media platforms may pose to democratic life.
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Affiliation(s)
- Amin Mekacher
- Department of Mathematics, City University of London, London EC1V 0HB, UK
| | - Max Falkenberg
- Department of Mathematics, City University of London, London EC1V 0HB, UK
| | - Andrea Baronchelli
- Department of Mathematics, City University of London, London EC1V 0HB, UK
- The Alan Turing Institute, British Library, London NW1 2DB, UK
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2
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Falkenberg M, Coleman JA, Dobson S, Hickey DJ, Terrill L, Ciacci A, Thomas B, Sau A, Ng FS, Zhao J, Peters NS, Christensen K. Identifying locations susceptible to micro-anatomical reentry using a spatial network representation of atrial fibre maps. PLoS One 2022; 17:e0267166. [PMID: 35737662 PMCID: PMC9223322 DOI: 10.1371/journal.pone.0267166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/03/2022] [Indexed: 11/18/2022] Open
Abstract
Micro-anatomical reentry has been identified as a potential driver of atrial fibrillation (AF). In this paper, we introduce a novel computational method which aims to identify which atrial regions are most susceptible to micro-reentry. The approach, which considers the structural basis for micro-reentry only, is based on the premise that the accumulation of electrically insulating interstitial fibrosis can be modelled by simulating percolation-like phenomena on spatial networks. Our results suggest that at high coupling, where micro-reentry is rare, the micro-reentrant substrate is highly clustered in areas where the atrial walls are thin and have convex wall morphology, likely facilitating localised treatment via ablation. However, as transverse connections between fibres are removed, mimicking the accumulation of interstitial fibrosis, the substrate becomes less spatially clustered, and the bias to forming in thin, convex regions of the atria is reduced, possibly restricting the efficacy of localised ablation. Comparing our algorithm on image-based models with and without atrial fibre structure, we find that strong longitudinal fibre coupling can suppress the micro-reentrant substrate, whereas regions with disordered fibre orientations have an enhanced risk of micro-reentry. With further development, these methods may be useful for modelling the temporal development of the fibrotic substrate on an individualised basis.
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Affiliation(s)
- Max Falkenberg
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- Department of Physics, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | - James A. Coleman
- Department of Physics, Imperial College London, London, United Kingdom
| | - Sam Dobson
- Department of Physics, Imperial College London, London, United Kingdom
| | - David J. Hickey
- Department of Physics, Imperial College London, London, United Kingdom
| | - Louie Terrill
- Department of Physics, Imperial College London, London, United Kingdom
| | - Alberto Ciacci
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- Department of Physics, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | - Belvin Thomas
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Arunashis Sau
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | - Fu Siong Ng
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Nicholas S. Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | - Kim Christensen
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- Department of Physics, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, National Heart & Lung Institute, Imperial College London, London, United Kingdom
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3
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Djerf H, Svensson M, Nordanstig J, Gottsäter A, Falkenberg M, Lindgren H. Cost Effectiveness of Primary Stenting in the Superficial Femoral Artery for Intermittent Claudication: Two Year Results of a Randomised Multicentre Trial. J Vasc Surg 2021. [DOI: 10.1016/j.jvs.2021.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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4
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Lundh C, Ivarsson J, Falkenberg M, Båth M, Almén A. A MODEL FOR EVALUATING THE USE OF IMAGING IN IMAGE-GUIDED INTERVENTIONAL PROCEDURES-POSSIBLE IMPLICATIONS ON OPTIMISATION OF RADIATION PROTECTION. Radiat Prot Dosimetry 2021; 195:139-144. [PMID: 33876241 DOI: 10.1093/rpd/ncab040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 10/30/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
The present study focuses on introducing the concept of optimisation and proposing a model, including evaluation of image quality, to be used in the clinical routines where image-guided intervention is being performed. The overall aim of the study was to develop a model for evaluating the use of imaging in X-ray-guided interventional procedures and its possible implications on optimisation of radiation protection. In the search for an adequate evaluation model, data from endovascular interventions of the aorta (EVAR procedures) were used. The procedure was schematically described in steps. Every imaging event was connected to the steps in the medical procedure and was also described with the purpose of the imaging event. Available technical, as well as procedural parameters, were studied and analysed. Data were collected from the X-ray equipment for 70 EVAR procedures and, out of these, 12 procedures were randomly selected to be recorded on video to understand the procedure better. It was possible to describe the EVAR procedures in a general way with explanations of the clinical purpose connected to each imaging event. Possible quality parameters of the procedure were identified for the imaging events (radiation dose, image quality). The model method still needs to be refined and will then be applied to clinical data and to other clinical procedures to test the validity.
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Affiliation(s)
- C Lundh
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45, Göteborg, Sweden
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Göteborg, Sweden
| | - J Ivarsson
- Department of Applied IT, University of Göteborg, SE-412 96, Göteborg, Sweden
| | - M Falkenberg
- Department of Radiology, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Göteborg, Sweden
| | - M Båth
- Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, SE-413 45, Göteborg, Sweden
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Göteborg, Sweden
| | - A Almén
- Department of Radiation Protection, Swedish Radiation Safety Authority, SE-171 16, Stockholm, Sweden
- Medical Radiation Physics, Department of Translational Medicine (ITM), Lund University, SE-205 02, Malmö, Sweden
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Cervin A, Acosta S, Hultgren R, Grip O, Björck M, Falkenberg M. Results After Open and Endovascular Repair of Popliteal Aneurysm: A Matched Comparison Within a Population Based Cohort. J Vasc Surg 2021. [DOI: 10.1016/j.jvs.2021.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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6
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Oldfors A, Hedberg-Oldfors C, Basu S, Lindgren U, Lindberg C, Larsson E, Falkenberg M. AUTOIMMUNE MYOPATHIES. Neuromuscul Disord 2020. [DOI: 10.1016/j.nmd.2020.08.300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Rajpal H, Sas M, Lockwood C, Joakim R, Peters NS, Falkenberg M. Interpretable XGBoost Based Classification of 12-lead ECGs Applying Information Theory Measures From Neuroscience. Comput Cardiol (2010) 2020; 47:185. [PMID: 33763495 PMCID: PMC7610399 DOI: 10.22489/cinc.2020.185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Automated ECG classification is a standard feature in many commercial 12-Lead ECG machines. As part of the Physionet/CinC Challenge 2020, our team, "Mad-hardmax", developed an XGBoost based classification method for the analysis of 12-Lead ECGs acquired from four different countries. Our aim is to develop an interpretable classifier that outputs diagnoses which can be traced to specific ECG features, while also testing the potential of information theoretic features for ECG diagnosis. These measures capture high-level interdependencies across ECG leads which are effective for discriminating conditions with multiple complex morphologies. On unseen test data, our algorithm achieved a challenge score of 0.155 relative to a winning score of 0.533, putting our submission in 24th position from 41 successful entries.
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Affiliation(s)
- Hardik Rajpal
- Centre for Complexity Science, Imperial College London, London, United Kingdom
| | - Madalina Sas
- Centre for Complexity Science, Imperial College London, London, United Kingdom
| | | | - Rebecca Joakim
- Wexham Park Hospital, Frimley Park NHS Foundation Trust, Slough, United Kingdom
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial College London, London, United Kingdom
| | - Max Falkenberg
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial College London, London, United Kingdom
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8
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Djerf H, Millinger J, Falkenberg M, Jivegard L, Svensson M, Nordanstig J. Absence of Long-term Benefit of Revascularization in Patients With Intermittent Claudication: Five-Year Results From the IRONIC Randomized Controlled Trial. J Vasc Surg 2020. [PMCID: PMC7374115 DOI: 10.1016/j.jvs.2020.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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9
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Ciacci A, Falkenberg M, Manani KA, Evans TS, Peters NS, Christensen K. Understanding the transition from paroxysmal to persistent atrial fibrillation. Phys Rev Res 2020; 2:023311. [PMID: 32607500 PMCID: PMC7326608 DOI: 10.1103/physrevresearch.2.023311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhytmia, characterized by the chaotic motion of electrical wavefronts in the atria. In clinical practice, AF is classified under two primary categories: paroxysmal AF, short intermittent episodes separated by periods of normal electrical activity; and persistent AF, longer uninterrupted episodes of chaotic electrical activity. However, the precise reasons why AF in a given patient is paroxysmal or persistent is poorly understood. Recently, we have introduced the percolation-based Christensen-Manani-Peters (CMP) model of AF which naturally exhibits both paroxysmal and persistent AF, but precisely how these differences emerge in the model is unclear. In this paper, we dissect the CMP model to identify the cause of these different AF classifications. Starting from a mean-field model where we describe AF as a simple birth-death process, we add layers of complexity to the model and show that persistent AF arises from reentrant circuits which exhibit an asymmetry in their probability of activation relative to deactivation. As a result, different simulations generated at identical model parameters can exhibit fibrillatory episodes spanning several orders of magnitude from a few seconds to months. These findings demonstrate that diverse, complex fibrillatory dynamics can emerge from very simple dynamics in models of AF.
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Affiliation(s)
- Alberto Ciacci
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
- Center for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
| | - Max Falkenberg
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
- Center for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
| | - Kishan A. Manani
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
- Center for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- National Heart and Lung Institute, Imperial College London, London W12 0NN, United Kingdom
| | - Tim S. Evans
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
- Center for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
| | - Nicholas S. Peters
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
| | - Kim Christensen
- Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
- Center for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- ElectroCardioMaths Programme, Imperial Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
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10
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Abstract
Most animal traps are constructed from self-secreted silk, so antlions are rare among trap builders because they use only materials found in the environment. We show how antlions exploit the properties of the substrate to produce very effective structures in the minimum amount of time. Our modelling demonstrates how antlions: (i) exploit self-stratification in granular media differentially to expose deleterious large grains at the bottom of the construction trench where they can be ejected preferentially, and (ii) minimize completion time by spiral rather than central digging. Both phenomena are confirmed by our experiments. Spiral digging saves time because it enables the antlion to eject material initially from the periphery of the pit where it is less likely to topple back into the centre. As a result, antlions can produce their pits—lined almost exclusively with small slippery grains to maximize powerful avalanches and hence prey capture—much more quickly than if they simply dig at the pit's centre. Our demonstration, for the first time to our knowledge, of an animal using self-stratification in granular media exemplifies the sophistication of extended phenotypes even if they are only formed from material found in the animal's environment.
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Affiliation(s)
- Nigel R Franks
- 1 School of Biological Sciences, University of Bristol , 24 Tyndall Avenue, Bristol BS8 1TQ , UK
| | - Alan Worley
- 1 School of Biological Sciences, University of Bristol , 24 Tyndall Avenue, Bristol BS8 1TQ , UK
| | - Max Falkenberg
- 2 Blackett Laboratory, Imperial College London , South Kensington Campus, London SW7 2AZ , UK.,3 Centre for Complexity Science, Imperial College London , South Kensington Campus, London SW7 2AZ , UK
| | - Ana B Sendova-Franks
- 4 Department of Engineering Design and Mathematics, UWE Bristol , Frenchay Campus, Coldharbour Lane, Bristol BS16 1QY , UK
| | - Kim Christensen
- 2 Blackett Laboratory, Imperial College London , South Kensington Campus, London SW7 2AZ , UK.,3 Centre for Complexity Science, Imperial College London , South Kensington Campus, London SW7 2AZ , UK
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McGreevy D, Abu-Zidan F, Sadeghi M, Pirouzram A, Toivola A, Skoog P, Idoguchi K, Kon Y, Ishida T, Matsumura Y, Matsumoto J, Reva V, Maszkowski M, Bersztel A, Caragounis E, Falkenberg M, Handolin L, Oosthuizen G, Szarka E, Manchev V, Wannatoop T, Chang S, Kessel B, Hebron D, Shaked G, Bala M, Coccolini F, Ansaloni L, Dogan E, Manning J, Hibert-Carius P, Larzon T, Nilsson K, Hörer T. Feasibility and Clinical Outcome Of REBOA in Patients With Impending Traumatic Cardiac Arrest. Eur J Vasc Endovasc Surg 2019. [DOI: 10.1016/j.ejvs.2019.09.443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Falkenberg M, Ford AJ, Li AC, Lawrence R, Ciacci A, Peters NS, Christensen K. Unified mechanism of local drivers in a percolation model of atrial fibrillation. Phys Rev E 2019; 100:062406. [PMID: 31962501 PMCID: PMC7314598 DOI: 10.1103/physreve.100.062406] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Indexed: 11/07/2022]
Abstract
The mechanisms of atrial fibrillation (AF) are poorly understood, resulting in disappointing success rates of ablative treatment. Different mechanisms defined largely by different atrial activation patterns have been proposed and, arguably, this dispute has slowed the progress of AF research. Recent clinical evidence suggests a unifying mechanism of local drivers based on sustained reentrant circuits in the complex atrial architecture. Here, we present a percolation inspired computational model showing spontaneous emergence of AF that strongly supports, and gives a theoretical explanation for, the clinically observed diversity of activation. We show that the difference in surface activation patterns is a direct consequence of the thickness of the discrete network of heart muscle cells through which electrical signals percolate to reach the imaged surface. The model naturally follows the clinical spectrum of AF spanning sinus rhythm, paroxysmal AF, and persistent AF as the decoupling of myocardial cells results in the lattice approaching the percolation threshold. This allows the model to make the prediction that, for paroxysmal AF, reentrant circuits emerge near the endocardium, but in persistent AF they emerge deeper in the bulk of the atrial wall. If experimentally verified, this may go towards explaining the lowering ablation success rate as AF becomes more persistent.
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Affiliation(s)
- Max Falkenberg
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Centre for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
| | - Andrew J. Ford
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Anthony C. Li
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Robert Lawrence
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - Alberto Ciacci
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Centre for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
| | - Nicholas S. Peters
- Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
- National Heart & Lung Institute, Imperial College London, London, W12 0NN, United Kingdom
| | - Kim Christensen
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Centre for Complexity Science, Imperial College London, London SW7 2AZ, United Kingdom
- Centre for Cardiac Engineering, Imperial College London, London W12 0NN, United Kingdom
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13
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Falkenberg M, Hickey D, Terrill L, Ciacci A, Peters NS, Christensen K. Identifying Potential Re-Entrant Circuit Locations From Atrial Fibre Maps. Comput Cardiol (2010) 2019; 2019:1-4. [PMID: 32514409 PMCID: PMC7279949 DOI: 10.22489/cinc.2019.102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Re-entrant circuits have been identified as potential drivers of atrial fibrillation (AF). In this paper, we develop a novel computational framework for finding the locations of re-entrant circuits from high resolution fibre orientation data. The technique follows a statistical approach whereby we generate continuous fibre tracts across the tissue and couple adjacent fibres stochastically if they are within a given distance of each other. By varying the connection distance, we identify which regions are most susceptible to forming re-entrant circuits if muscle fibres are uncoupled, through the action of fibrosis or otherwise. Our results highlight the sleeves of the pulmonary veins, the posterior left atrium and the left atrial appendage as the regions most susceptible to re-entrant circuit formation. This is consistent with known risk locations in clinical AF. If the model can be personalised for individual patients undergoing ablation, future versions may be able to suggest suitable ablation targets.
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Affiliation(s)
- Max Falkenberg
- Blackett Laboratory, Imperial College London, London, United Kingdom
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial College London, London, United Kingdom
| | - David Hickey
- Blackett Laboratory, Imperial College London, London, United Kingdom
| | - Louie Terrill
- Blackett Laboratory, Imperial College London, London, United Kingdom
| | - Alberto Ciacci
- Blackett Laboratory, Imperial College London, London, United Kingdom
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial College London, London, United Kingdom
| | - Nicholas S Peters
- ElectroCardioMaths Programme, Imperial College London, London, United Kingdom
| | - Kim Christensen
- Blackett Laboratory, Imperial College London, London, United Kingdom
- Centre for Complexity Science, Imperial College London, London, United Kingdom
- ElectroCardioMaths Programme, Imperial College London, London, United Kingdom
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14
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Baubeta Fridh E, Andersson M, Thuresson M, Sigvant B, Kragsterman B, Johansson S, Hasvold P, Nordanstig J, Falkenberg M. Impact of Comorbidity, Medication, and Gender on Amputation Rate Following Revascularisation for Chronic Limb Threatening Ischaemia. J Vasc Surg 2018. [DOI: 10.1016/j.jvs.2018.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Djerf H, Falkenberg M, Jivegård L, Lindgren H, Svensson M, Nordanstig J. Cost-effectiveness of revascularization in patients with intermittent claudication. Br J Surg 2018; 105:1742-1748. [PMID: 30357819 DOI: 10.1002/bjs.10992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/06/2018] [Accepted: 08/06/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND Revascularization is a treatment option for patients with intermittent claudication. However, there is a lack of evidence to support its long-term benefits and cost-effectiveness. The aim of this study was to compare the cost-effectiveness of revascularization and best medical therapy (BMT) with that of BMT alone. METHODS Data were used from the IRONIC (Invasive Revascularization Or Not in Intermittent Claudication) RCT where consecutive patients with mild-to-severe intermittent claudication owing to aortoiliac or femoropopliteal disease were allocated to either BMT alone (including a structured, non-supervised exercise programme) or to revascularization together with BMT. Inpatient and outpatient costs were obtained prospectively over 24 months of follow-up. Mean improvement in quality-adjusted life-years (QALYs) was calculated based on responses to the EuroQol Five Dimensions EQ-5D-3 L™ questionnaire. Cost-effectiveness was assessed as the cost per QALY gained. RESULTS A total of 158 patients were randomized, 79 to each group. The mean cost per patient in the BMT group was €1901, whereas it was €8280 in the group treated with revascularization in addition to BMT, with a cost difference of €6379 (95 per cent c.i. €4229 to 8728) per patient. Revascularization in addition to BMT resulted in a mean gain in QALYs of 0·16 (95 per cent c.i. 0·06 to 0·24) per patient, giving an incremental cost-effectiveness ratio of €42 881 per QALY. CONCLUSION The costs associated with revascularization together with BMT in patients with intermittent claudication were about four times higher than those of BMT alone. The incremental cost-effectiveness ratio of revascularization was within the accepted threshold for public willingness to pay according to the Swedish National Guidelines, but exceeded that of the UK National Institute for Health and Care Excellence guidelines.
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Affiliation(s)
- H Djerf
- Department of Vascular Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department of Radiology, Institute of Clinical Science, Gothenburg, Sweden
| | - M Falkenberg
- Department of Radiology, Institute of Clinical Science, Gothenburg, Sweden
| | - L Jivegård
- Health Technology Assessment Centre, Västra Götaland, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department for Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
| | - H Lindgren
- Department of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden.,Department of Surgery, Helsingborg Hospital, Helsingborg, Sweden
| | - M Svensson
- Health Metrics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - J Nordanstig
- Department of Vascular Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden.,Department for Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden
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16
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Sadeghi M, Nilsson KF, Larzon T, Pirouzram A, Toivola A, Skoog P, Idoguchi K, Kon Y, Ishida T, Matsumara Y, Matsumoto J, Reva V, Maszkowski M, Bersztel A, Caragounis E, Falkenberg M, Handolin L, Kessel B, Hebron D, Coccolini F, Ansaloni L, Madurska MJ, Morrison JJ, Hörer TM. The use of aortic balloon occlusion in traumatic shock: first report from the ABO trauma registry. Eur J Trauma Emerg Surg 2018; 44:491-501. [PMID: 28801841 PMCID: PMC6096626 DOI: 10.1007/s00068-017-0813-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/04/2017] [Indexed: 11/09/2022]
Abstract
PURPOSE Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a technique for temporary stabilization of patients with non-compressible torso hemorrhage. This technique has been increasingly used worldwide during the past decade. Despite the good outcomes of translational studies, clinical studies are divided. The aim of this multicenter-international study was to capture REBOA-specific data and outcomes. METHODS REBOA practicing centers were invited to join this online register, which was established in September 2014. REBOA cases were reported, both retrospective and prospective. Demographics, injury patterns, hemodynamic variables, REBOA-specific data, complications and 30-days mortality were reported. RESULTS Ninety-six cases from 6 different countries were reported between 2011 and 2016. Mean age was 52 ± 22 years and 88% of the cases were blunt trauma with a median injury severity score (ISS) of 41 (IQR 29-50). In the majority of the cases, Zone I REBOA was used. Median systolic blood pressure before balloon inflation was 60 mmHg (IQR 40-80), which increased to 100 mmHg (IQR 80-128) after inflation. Continuous occlusion was applied in 52% of the patients, and 48% received non-continuous occlusion. Occlusion time longer than 60 min was reported as 38 and 14% in the non-continuous and continuous groups, respectively. Complications, such as extremity compartment syndrome (n = 3), were only noted in the continuous occlusion group. The 30-day mortality for non-continuous REBOA was 48%, and 64% for continuous occlusion. CONCLUSIONS This observational multicenter study presents results regarding continuous and non-continuous REBOA with favorable outcomes. However, further prospective studies are needed to be able to draw conclusions on morbidity and mortality.
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Affiliation(s)
- M Sadeghi
- Västmanlands Hospital Västerås, Department of Vascular Surgery, Örebro University, Örebro, Sweden
| | - K F Nilsson
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University Hospital, 701 85, Örebro, Sweden
| | - T Larzon
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University Hospital, 701 85, Örebro, Sweden
| | - A Pirouzram
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University Hospital, 701 85, Örebro, Sweden
| | - A Toivola
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University Hospital, 701 85, Örebro, Sweden
| | - P Skoog
- Department of Vascular Surgery, Örebro University, Örebro, Sweden
| | - K Idoguchi
- Senshu Trauma and Critical Care Center, Rinku General Medical Center, Izumisano, Japan
| | - Y Kon
- Emergency and Critical Care Center, Hachinohe City Hospital, Hachinohe, Japan
| | - T Ishida
- Emergency and Critical Care Center, Ohta Nishinouchi Hospital, Koriyama, Japan
| | - Y Matsumara
- Department of Emergency and Critical Care Medicine, Chiba University Graduate School of Medicine, Chiba, Japan
- R Adams Cowley Shock Trauma Center, University of Maryland, College Park, MD, USA
| | - J Matsumoto
- Department of Emergency and Critical Care Medicine, St Marianna University School of Medicine, Kawasaki, Japan
| | - V Reva
- Department of War Surgery, Kirov Military Medical Academy, Saint Petersburg, Russia
- Dzhanelidze Research Institute of Emergency Medicine, Saint Petersburg, Russia
| | - M Maszkowski
- Västmanlands Hospital Västerås, Department of Vascular Surgery, Örebro University, Örebro, Sweden
| | - A Bersztel
- Västmanlands Hospital Västerås, Department of Vascular Surgery, Örebro University, Örebro, Sweden
| | - E Caragounis
- Sahlgrenska University Hospital, Department of Surgery, University of Gothenburg, Gothenburg, Sweden
| | - M Falkenberg
- Department of Radiology, Örebro University, Örebro, Sweden
| | - L Handolin
- Helsinki University Hospital, Department of Orthopedics and Traumatology, University of Helsinki, Helsinki, Finland
| | - B Kessel
- Department of Surgery, Hillel Yaffe Medical Centre, Hadera, Israel
| | - D Hebron
- Department of Surgery, Hillel Yaffe Medical Centre, Hadera, Israel
| | - F Coccolini
- Department of Surgery, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - L Ansaloni
- Department of Surgery, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - M J Madurska
- Department of Vascular Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - J J Morrison
- Department of Vascular Surgery, Queen Elizabeth University Hospital, Glasgow, UK
| | - T M Hörer
- Department of Cardiothoracic and Vascular Surgery, Faculty of Medicine and Health, Örebro University Hospital, 701 85, Örebro, Sweden.
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Baubeta Fridh E, Andersson M, Thuresson M, Sigvant B, Kragsterman B, Johansson S, Hasvold P, Falkenberg M, Nordanstig J. Amputation Rates, Mortality, and Pre-operative Comorbidities in Patients Revascularised for Intermittent Claudication or Critical Limb Ischaemia: A Population Based Study. J Vasc Surg 2017. [DOI: 10.1016/j.jvs.2017.08.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Baubeta Fridh E, Andersson M, Thuresson M, Sigvant B, Kragsterman B, Johansson S, Hasvold P, Falkenberg M, Nordanstig J. Amputation Rates, Mortality, and Pre-operative Comorbidities in Patients Revascularised for Intermittent Claudication or Critical Limb Ischaemia: A Population Based Study. Eur J Vasc Endovasc Surg 2017; 54:480-486. [DOI: 10.1016/j.ejvs.2017.07.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 07/09/2017] [Indexed: 10/19/2022]
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Nordanstig J, Pettersson M, Morgan M, Falkenberg M, Kumlien C. Assessment of Minimum Important Difference and Substantial Clinical Benefit with the Vascular Quality of Life Questionnaire-6 when Evaluating Revascularisation Procedures in Peripheral Arterial Disease. Eur J Vasc Endovasc Surg 2017; 54:340-347. [PMID: 28754429 DOI: 10.1016/j.ejvs.2017.06.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/27/2017] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Patient reported outcomes are increasingly used to assess outcomes after peripheral arterial disease (PAD) interventions. VascuQoL-6 (VQ-6) is a PAD specific health-related quality of life (HRQoL) instrument for routine clinical practice and clinical research. This study assessed the minimum important difference for the VQ-6 and determined thresholds for the minimum important difference and substantial clinical benefit following PAD revascularisation. MATERIALS AND METHODS This was a population-based observational cohort study. VQ-6 data from the Swedvasc Registry (January 2014 to September 2016) was analysed for revascularised PAD patients. The minimum important difference was determined using a combination of a distribution based and an anchor-based method, while receiver operating characteristic curve analysis (ROC) was used to determine optimal thresholds for a substantial clinical benefit following revascularisation. RESULTS A total of 3194 revascularised PAD patients with complete VQ-6 baseline recordings (intermittent claudication (IC) n = 1622 and critical limb ischaemia (CLI) n = 1572) were studied, of which 2996 had complete VQ-6 recordings 30 days and 1092 a year after the vascular intervention. The minimum important difference 1 year after revascularisation for IC patients ranged from 1.7 to 2.2 scale steps, depending on the method of analysis. Among CLI patients, the minimum important difference after 1 year was 1.9 scale steps. ROC analyses demonstrated that the VQ-6 discriminative properties for a substantial clinical benefit was excellent for IC patients (area under curve (AUC) 0.87, sensitivity 0.81, specificity 0.76) and acceptable in CLI (AUC 0.736, sensitivity 0.63, specificity 0.72). An optimal VQ-6 threshold for a substantial clinical benefit was determined at 3.5 scale steps among IC patients and 4.5 in CLI patients. CONCLUSIONS The suggested thresholds for minimum important difference and substantial clinical benefit could be used when evaluating VQ-6 outcomes following different interventions in PAD and in the design of clinical trials.
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Affiliation(s)
- J Nordanstig
- Department of Vascular Surgery and Institute of Medicine, Department of Molecular and Clinical Medicine, Sahlgrenska University Hospital and Academy, Gothenburg University, Gothenburg, Sweden.
| | - M Pettersson
- Health and Care Sciences, Gothenburg University, Gothenburg, Sweden
| | - M Morgan
- Bay of Plenty Clinical School, Tauranga Hospital, Tauranga, New Zealand
| | - M Falkenberg
- Department of Radiology, Institute of Clinical Science, Sahlgrenska Academy, Gothenburg, Sweden
| | - C Kumlien
- Department of Cardio-Thoracic and Vascular Surgery and Faculty of Health and Society, Department of Care Science, Malmö University, Malmö, Sweden
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Koutouzi G, Sandström C, Roos H, Henrikson O, Leonhardt H, Falkenberg M. Orthogonal Rings, Fiducial Markers, and Overlay Accuracy When Image Fusion is Used for EVAR Guidance. Eur J Vasc Endovasc Surg 2016; 52:604-611. [DOI: 10.1016/j.ejvs.2016.07.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 07/19/2016] [Indexed: 10/21/2022]
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Roos H, Tokarev M, Chernoray V, Ghaffari M, Falkenberg M, Jeppsson A, Nilsson H. Displacement Forces in Stent Grafts: Influence of Diameter Variation and Curvature Asymmetry. Eur J Vasc Endovasc Surg 2016; 52:150-6. [DOI: 10.1016/j.ejvs.2016.04.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 04/16/2016] [Indexed: 10/21/2022]
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Hammarsten J, Bernland P, Campanello M, Falkenberg M, Henrikson O, Jensen J. A Study of the Mechanisms by Which Haemodynamic Function Improves following Long Saphenous Vein-Saving Surgery. Phlebology 2016. [DOI: 10.1177/026835559601100307] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective: To study the mechanisms by which haemodynamic function improves following long saphenous vein-saving surgery. Design: Cohort study. Patients: Twenty patients, 14 women and six men, with primary varicose veins. Interventions: Varicose vein surgery by the long saphenous vein-saving technique. Main outcome measures: Preoperative investigation by physical examination, strain-gauge plethysmography, phlebography and measurements of the long saphenous vein diameter at four different locations using high-resolution, real-time ultrasound. Three months following vein-saving surgery, the patients were reassessed with physical examination, strain-gauge plethysmography and measurements of the long saphenous vein diameter. Results: All patients but one showed excellent or good results following surgery. The preoperative diameter of the long saphenous vein was reduced by 40% at four different levels in the operated legs ( p<0.01). The venous return time of the same legs increased 2.4 times ( p<0.001). The decrease of the long saphenous vein diameter correlated positively with the increase in venous return time (t-50), ( r=0.50, p=0.04). Conclusion: The results suggest that the development of incompetent perforators is an early major event in the formation of primary varicose veins. The results also suggest that the long saphenous vein valvular incompetence in varicose veins is attributable to venous wall dilatation rather than degeneration of the valves. The results support the hypothesis that the improvement in haemodynamic function following long saphenous vein-saving surgery is due, at least partly, to a reduction of the long saphenous vein diameter, which in turn tends to restore valvular competence.
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Affiliation(s)
- J. Hammarsten
- Department of Surgery, Varberg Hospital, Varberg, Sweden
| | - P. Bernland
- Department of Radiology, Varberg Hospital, Varberg, Sweden
| | - M. Campanello
- Department of Surgery, Varberg Hospital, Varberg, Sweden
| | - M. Falkenberg
- Department of Surgery, Varberg Hospital, Varberg, Sweden
| | - O. Henrikson
- Department of Radiology, Varberg Hospital, Varberg, Sweden
| | - J. Jensen
- Department of Radiology, Varberg Hospital, Varberg, Sweden
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Larzon T, Roos H, Gruber G, Henrikson O, Magnuson A, Falkenberg M, Lönn L, Norgren L. A Randomized Controlled Trial of the Fascia Suture Technique Compared with a Suture-mediated Closure Device for Femoral Arterial Closure after Endovascular Aortic Repair. J Vasc Surg 2015. [DOI: 10.1016/j.jvs.2014.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Larzon T, Roos H, Gruber G, Henrikson O, Magnuson A, Falkenberg M, Lönn L, Norgren L. Editor's Choice - A Randomized Controlled Trial of the Fascia Suture Technique Compared with a Suture-mediated Closure Device for Femoral Arterial Closure after Endovascular Aortic Repair. Eur J Vasc Endovasc Surg 2015; 49:166-73. [DOI: 10.1016/j.ejvs.2014.10.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 10/03/2014] [Indexed: 12/17/2022]
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Österberg K, Falkenberg M, Resch T. Endovascular Technique for Arterial Shunting to Prevent Intraoperative Ischemia. J Vasc Surg 2014. [DOI: 10.1016/j.jvs.2014.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Österberg K, Falkenberg M, Resch T. Endovascular Technique for Arterial Shunting to Prevent Intraoperative Ischemia. Eur J Vasc Endovasc Surg 2014; 48:126-30. [DOI: 10.1016/j.ejvs.2014.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/14/2014] [Indexed: 11/25/2022]
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Larzon T, Falkenberg M, Lonn L. The management of ruptured abdominal aortic aneurysms. J Cardiovasc Surg (Torino) 2014; 55:133-135. [PMID: 24670821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- T Larzon
- Department of Cardiothoracic and Vascular Surgery Örebro University Hospital, Örebro, Sweden -
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Roos H, Ghaffari M, Falkenberg M, Chernoray V, Jeppsson A, Nilsson H. Displacement Forces in Iliac Landing Zones and Stent Graft Interconnections in Endovascular Aortic Repair: An Experimental Study. Eur J Vasc Endovasc Surg 2014; 47:262-7. [DOI: 10.1016/j.ejvs.2013.11.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/29/2013] [Indexed: 10/25/2022]
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Roos S, Macao B, Fuste JM, Lindberg C, Jemt E, Holme E, Moslemi AR, Oldfors A, Falkenberg M. Subnormal levels of POL A cause inefficient initiation of light-strand DNA synthesis and lead to mitochondrial DNA deletions and progressive external ophthalmoplegia. Hum Mol Genet 2013. [DOI: 10.1093/hmg/ddt491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Falkenberg M, Kiesel L. Hormone und Karzinogenese beim Mammakarzinom. Gynäkologische Endokrinologie 2013. [DOI: 10.1007/s10304-013-0567-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bech B, Lönn L, Falkenberg M, Bartholdy N, Räder S, Schroeder T, Ringsted C. Construct Validity and Reliability of Structured Assessment of endoVascular Expertise in a Simulated Setting. Eur J Vasc Endovasc Surg 2011; 42:539-48. [DOI: 10.1016/j.ejvs.2011.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 05/05/2011] [Indexed: 11/30/2022]
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Abstract
BACKGROUND AND AIMS This retrospective study was undertaken to examine the risks associated with obstruction of the coeliac trunk in the process of treating aneurysms with endografting. MATERIAL AND METHODS 120 patients were treated by endografting for aneurysmal disease. Of these, a subgroup of 9 patients had their celiac trunk covered. If possible, a preoperative angiography was performed to evaluate collateral flow from the superior mesenteric artery. This was considered to predict the risk for ischemia. RESULTS None of the patients had any severe clinical event of the celiac trunk occlusion or clinical signs of intestinal ischemia. Three patients had transient increase of liver enzymes. CONCLUSIONS In cases where the distal landing zone of the descending thoracic aorta is to short for endografting, covering of the celiac trunk may be an option if no other surgical alter-native is apparent. Preoperative angiography to visualise the presence of collateral vessels from the superior mesenteric artery is recommended.
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Affiliation(s)
- M Delle
- Department of Radiology, Södersjukhuset, Stockholm, Sweden
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Mora-Cristancho JA, Arévalo-Ferro C, Ramos FA, Tello E, Duque C, Lhullier C, Falkenberg M, Schenkel EP. Antifouling Activities against Colonizer Marine Bacteria of Extracts from Marine Invertebrates Collected in the Colombian Caribbean Sea and on the Brazilian Coast (Santa Catarina). Z NATURFORSCH C 2011. [DOI: 10.5560/znc.2011.66c0515] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Falkenberg M, Gabel H, Gothman B, Holm J, Norback B, Schersten T. Abdominal Aortic Aneurysm: An Interhospital Study of 171 Surgically Treated Patients. Acta Radiol 2010. [DOI: 10.3109/00016924809133046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Falkenberg M, Lönn L, Schroeder T, Delle M. TEVAR and covering the celiac artery. Is it safe or not? J Cardiovasc Surg (Torino) 2010; 51:177-182. [PMID: 20354487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Thoracic endovascular aortic repair (TEVAR) is the treatment of choice for descending thoracic aortic aneurysms (TAA). However, not all patients with TAA can be treated with the endovascular technique. Insufficient proximal and/or distal sealing zone is the most common reason for open surgery in these patients. If the distal sealing zone above the celiac axis is too short, several endovascular alternatives are possible; hybrid procedures with TEVAR and open by-pass to the celiac artery, custom made stent-grafts with scallop or fenestration for the celiac artery, or intentional coverage of the celiac artery. In the latter case, adequate collateral supply to the upper gastrointestinal tract is crucial. Collateral arteries joining the celiac and the superior mesenteric arteries are well characterized in patients with chronic celiac stenosis or occlusion. Are these collateral pathways sufficient also for sudden iatrogenic closure of the celiac artery? By performing a preoperative angiography of the superior mesenteric artery with temporary balloon occlusion of the celiac artery, collateral capacity between the two vessels can be tested in advance. Exact positioning of the distal end of a large thoracic stent-graft can be challenging and require special considerations and techniques. Most case series in the literature support the efficacy and the safety of intentional celiac covering. However, there are also reports of ischemic foregut complications that could be associated to the procedure. Taken together, in the large majority of patients, it appears that intentional celiac coverage can be done safely provided that sufficient collateral function have been demonstrated in advance.
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Affiliation(s)
- M Falkenberg
- Department of Radiology, Sahlgrenska University Hospital, Gothenburg, Sweden.
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Falkenberg M, Kågedal B, Norr A. Screening of an elderly female population for hypo- and hyperthyroidism by use of a thyroid hormone panel. Acta Med Scand 2009; 214:361-5. [PMID: 6660045 DOI: 10.1111/j.0954-6820.1983.tb08609.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The elderly female population living in a rural primary health care district in the south of Sweden was screened for hypo- and hyperthyroidism. A total of 1 442 (97.3%) of the 1 482 women 60 years of age or older attended the study. By use of a computer-evaluated thyroid hormone panel, 178 women (12.3%) were identified as probably abnormal. Among them, 8 women (0.55% of total) with previously unknown thyroid disease were detected as overtly hypothyroid. If also 13 women with spontaneous subclinical hypothyroidism were included, the prevalence of earlier unknown hypothyroidism was 21/1 442 (1.5%). The number of subjects with hyperthyroidism discovered by screening was 28/1 442 (1.9%). Although much remains to be elucidated regarding medical, social and economic factors, the high figures obtained for newly discovered abnormal thyroid function suggest that screening for hyper- and hypothyroidism may be worthwhile in such an elderly female population.
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Hinchliffe RJ, Krasznai A, Schultzekool L, Blankensteijn JD, Falkenberg M, Lönn L, Hausegger K, de Blas M, Egana JM, Sonesson B, Ivancev K. Observations on the Failure of Stent-grafts in the Aortic Arch. Eur J Vasc Endovasc Surg 2007; 34:451-6. [PMID: 17669668 DOI: 10.1016/j.ejvs.2007.06.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Accepted: 06/04/2007] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The results of endovascular stent-grafts in the abdominal aorta and descending thoracic aorta have been encouraging. Expanding the use of thoracic stent-grafts in to the aortic arch has been associated with increasing numbers of complications. Recently isolated cases of stent-graft collapse have been reported. METHODS This was a multi-centre European case series. Data was collected retrospectively on seven patients from five experienced endovascular centres with thoracic stent-graft collapse. RESULTS Of the seven patients four were treated for traumatic aortic rupture. Six were male, median age 33 (range 17-54) years. During the ensuing 2 months all patients suffered stent-graft collapse. This was symptomatic in 3 patients and the rest were identified on CT. Endovascular management was possible in 6/7 patients using either a balloon expandable stent (n=6) or further stent-graft (n=1). Two patients had persistent type I endoleak despite treatment. Two of the 7 patients died, both of which presented with symptomatic thoracic stent-graft occlusion. Both deaths were a direct result of stent-graft collapse. CONCLUSIONS Thoracic stent-graft collapse may be asymptomatic underscoring the importance of stent-graft surveillance. Endovascular management of collapse is possible in most cases using a large balloon expandable stent. Symptomatic collapse is associated with high morbidity and mortality.
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Affiliation(s)
- R J Hinchliffe
- Endovascular Department, Malmö University Hospital, Malmö, Sweden.
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Resch TA, Delle M, Falkenberg M, Ivancev K, Konrad P, Larzon T, Lönn L, Malina M, Nyman R, Sonesson B, Thelin S. Remodeling of the thoracic aorta after stent grafting of type B dissection: a Swedish multicenter study. J Cardiovasc Surg (Torino) 2006; 47:503-8. [PMID: 17033599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
AIM Endovascular repair of complicated type B dissections has evolved as a promising alternative to open repair. Previous studies have indicated that continued false lumen flow is a predictor of continued aortic dilatation and risk of rupture during follow-up. This multicenter study was conducted to analyze the postoperative changes of the false lumen after endografting of complicated type B dissections. METHODS All patients treated with endovascular stent grafts for thoracic type B dissections at 5 major Vascular Centers in Sweden were identified through local databases. Review of charts and all available pre- and postoperative CT scans were performed to identify demographics, indications for repair as well as postoperative changes of the aorta and false lumen. RESULTS A total of 129 patients treated for type B dissections between 1994 and December 2005 were identified. Median radiological follow-up was 14 months. Fourteen patients died perioperatively leaving 115 patients available for analysis. Seventy-four of these had CT imaging of sufficient quality for morphological analysis. The vast majority of acute patients were treated for rupture or end-organ ischemia whereas most chronic patients were treated for asymptomatic aneurysms. In 80% of patients, the false lumen thrombosed along the stent graft but it remained perfused distal to the stent graft fixation in 50% of patients. Only 5% of patients presented with aortic enlargement of the stent grafted area when adequate proximal sealing was achieved. The distal, uncovered aorta displayed expansion in 16% of patients. CONCLUSIONS The stent grafted thoracic aorta after type B dissection appears to be stabilized by covering the primary entry site with a stent graft in the majority of both acute and chronic dissections. The uncovered portion of the aorta distal to the stent graft, however, remains at risk of continuous dilatation. Stent grafting for complicated type B thoracic dissections seems to be a treatment option with reasonable morbidity and mortality even though the incidence of severe complications is still significant.
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Affiliation(s)
- T A Resch
- Department of Vascular Diseases, Malmö University Hospital, Malmö, Sweden.
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Tjärnström J, Holmdahl L, Falk P, Falkenberg M, Arnell P, Risberg B. Effects of hyperbaric oxygen on expression of fibrinolytic factors of human endothelium in a simulated ischaemia/reperfusion situation. Scand J Clin Lab Invest 2002; 61:539-45. [PMID: 11763412 DOI: 10.1080/003655101753218300] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
BACKGROUND Treatment with hyperbaric oxygen (HBO2) is controversial when treating disorders other than decompression sickness. Still, HBO2 is a treatment modality that has gained recognition in certain situations of ischaemia reperfusion. However, not much is known about its effect on the endothelial cells. Based on earlier studies, the hypothesis was that HBO2 treatment stimulates the release of fibrinolytic factors. The aim of the study was to investigate the effect of HBO2 treatment on cultured endothelial cells in a simulated ischaemia-reperfusion model. METHODS To mimic the clinical situation during ischaemia reperfusion, endothelial cells were subjected to anoxia for 8 h, followed by reperfusion with either HBO2 or normobaric air for 1.5 h, and compared with an untreated control that was not exposed to anoxia. Components investigated were the fibrinolytic stimulator tissue plasminogen activator (t-PA), urokinase plasminogen activator (uPA) and the antagonist. plasminogen activator inhibitor type one (PAI-1). RESULTS Immediately after 8 h of total anoxia and reoxygenation with HBO2 (for 1.5 h), the mean (SEM) concentrations of t-PA, PAI-1 and uPA were significantly increased compared to the other groups. The difference between the normobaric and control groups, measured at 1.5 h, 6 h and 24 h post-anoxia, persisted throughout the experiment. CONCLUSION In this ischaemia-reperfusion model. HBO2 stimulates the release of fibrinolytic factors. These observations might be relevant in trauma care in preventing thromboses and/or microembolization following ischaemia-reperfusion.
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Affiliation(s)
- J Tjärnström
- Departments of Surgery, Sahlgrenska University Hospital Göteborg, Sweden.
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Ward P, Falkenberg M, Elias P, Weitzman M, Linden RM. Rep-dependent initiation of adeno-associated virus type 2 DNA replication by a herpes simplex virus type 1 replication complex in a reconstituted system. J Virol 2001; 75:10250-8. [PMID: 11581393 PMCID: PMC114599 DOI: 10.1128/jvi.75.21.10250-10258.2001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Accepted: 07/20/2001] [Indexed: 01/26/2023] Open
Abstract
Productive infection by adeno-associated virus type 2 (AAV) requires coinfection with a helper virus, e.g., adenovirus or herpesviruses. In the case of adenovirus coinfection, the replication machinery of the host cell performs AAV DNA replication. In contrast, it has been proposed that the herpesvirus replication machinery might replicate AAV DNA. To investigate this question, we have attempted to reconstitute AAV DNA replication in vitro using purified herpes simplex virus type 1 (HSV-1) replication proteins. We show that the HSV-1 UL5, UL8, UL29, UL30, UL42, and UL52 gene products along with the AAV Rep68 protein are sufficient to initiate replication on duplex DNA containing the AAV origins of replication, resulting in products several hundred nucleotides in length. Initiation can occur also on templates containing only a Rep binding site and a terminal resolution site. We further demonstrate that initiation of DNA synthesis can take place with a subset of these factors: Rep68 and the UL29, UL30, and UL42 gene products. Since the HSV polymerase and its accessory factor (the products of the UL30 and UL42 genes) are unable to efficiently perform synthesis by strand displacement, it is likely that in addition to creating a hairpin primer, the AAV Rep protein also acts as a helicase for DNA synthesis. The single-strand DNA binding protein (the UL29 gene product) presumably prevents reannealing of complementary strands. These results suggest that AAV can use the HSV replication apparatus to replicate its DNA. In addition, they may provide a first step for the development of a fully reconstituted AAV replication assay.
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Affiliation(s)
- P Ward
- Institute for Gene Therapy and Molecular Medicine, Mount Sinai School of Medicine, New York, New York 10029, USA.
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Falkenberg M. [Check your waist circumference! Overweight, obesity and abdominal obesity risk factors of type 2 diabetes]. Lakartidningen 2001; 98:3520-2. [PMID: 11571793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The object with the present study was to present prevalence data in a rural area in Sweden regarding overweight, obesity and abdominal obesity presented by waist circumference. The study was population-based in primary health care. The target group was aged 20 years or more. A total of 91% (n = 6,686) participated. 45% of men and 32% of women were overweight (BMI 25-29.9 kg/m2), 12% of men and 17% of women were obese (BMI > or = 30 kg/m2). The programme found among men 25.8% with a waist circumference 94-101.9 cm and 18.0% > or = 102 cm and among women 22.7% with 80.0-87.9 cm and 27.2% > or = 88 cm. The relative risk for type 2 diabetes increased with waist circumference. Making health care personnel and patients aware of overweight, obesity and abdominal obesity and the risk of associated diseases and encourage a healthy life style is urgent in time of an obesity epidemic.
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Affiliation(s)
- M Falkenberg
- Faculty of Health Sciences, Hälsouniversitetet, SE-581 85 Linkoping.
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Falkenberg M, Holmdahl L, Tjärnström J, Risberg B. Abnormal levels of urokinase plasminogen activator protein and tissue plasminogen activator activity in human aortic aneurysms. Eur J Surg 2001; 167:10-4. [PMID: 11213813 DOI: 10.1080/110241501750069747] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
OBJECTIVE To measure the concentrations and activities of plasminogen activators and plasminogen activator inhibitors in human abdominal aneurysms. DESIGN Laboratory study. SETTING University hospital, Sweden. MATERIAL Biopsy specimens from 12 abdominal aortic aneurysms and 8 normal aortas (controls). INTRERVENTIONS: Tissues were homogenised and eluted. The supernatants were assayed for antigens of tissue and urokinase plasminogen activator and plasminogen activator inhibitor 1 and 2. The activities of tissue plasminogen activator and plasminogen activator inhibitor-1 were assayed by ELISA. Frozen sections were immunostained for tissue and urokinase plasminogen activators and for plasminogen activator inhibitor-1. MAIN OUTCOME MEASURES Concentrations and activities of these activators and inhibitors. RESULTS The concentration of urokinase plasminogen activator antigen was higher in aneurysmal walls than in normal aortas; it was detected immunohistochemically in aneurysmal but not in normal aortas. The concentration (and the detection immunohistochemically) of tissue plasminogen activator was equal in aneurysmal and normal aortas, but its activity was reduced in the aneurysmal wall. Plasminogen activator inhibitor-1 did not differ significantly between the groups. CONCLUSIONS Urokinase plasminogen activator may be responsible for the digestion of the media of the aorta and the development of an aneurysm. Reduced activity of tissue plasminogen activator may be responsible for thrombosis in the aneurysm.
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Affiliation(s)
- M Falkenberg
- Department of Vascular Surgery, Sahlgrenska University Hospital, Göteborg University, Sweden
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Falkenberg M. [Time for home-based screening of type 2 diabetes]. Lakartidningen 2000; 97:4352. [PMID: 11076483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Falkenberg M. [HbA1C control also in patients with diabetes type 2!]. Lakartidningen 2000; 97:4046. [PMID: 11036370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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Falkenberg M, Lehman IR, Elias P. Leading and lagging strand DNA synthesis in vitro by a reconstituted herpes simplex virus type 1 replisome. Proc Natl Acad Sci U S A 2000; 97:3896-900. [PMID: 10760262 PMCID: PMC18113 DOI: 10.1073/pnas.97.8.3896] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The synthesis of double-stranded DNA by a rolling circle mechanism was reconstituted in vitro with a replisome consisting of the DNA polymerase-UL42 complex and the heterotrimeric helicase-primase encoded by herpes simplex virus type 1. Okazaki fragments 3 kilobases in length and leading strands that may exceed 10 kilobases are produced. Lagging strand synthesis is stimulated by ribonucleoside triphosphates. DNA replication appears to be processive because it resists competition with an excess of (dT)(150)/(dA)(20). The single-strand DNA binding protein ICP8 is not required, and high concentrations of ICP8 can, in fact, inhibit lagging strand synthesis. The inhibition can, however, be overcome by the addition of an excess of the UL8 component of the helicase-primase. Rolling circle replication by the herpesvirus and bacteriophage T7 replisomes appears to proceed by a similar mechanism.
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Affiliation(s)
- M Falkenberg
- Department of Medical Biochemistry, Göteborg University, Box 440, S-405 30 Göteborg, Sweden
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Abstract
In skin lesions of chronic venous incompetence (CVI) transcutaneous oxygen pressure (tcpO(2)) at the ankle is often reduced. However, in some CVI patients the tcpO(2) during suprasystolic occlusion remains significantly higher than in healthy subjects. The aim of the present study was to investigate which kind of CVI patients develop this phenomenon and whether the higher tcpO(2) during occlusion is caused by a smaller oxygen consumption of the skin or by an increased local oxygen content. The oxygen consumption of the skin was measured by the pO(2) decrease (DeltatcpO(2)/Deltat) after stopping the arterial oxygen supply when the hemoglobin was saturated by oxygen inhalation, i.e., at tcpO(2) values above 120-130 mmHg. By multiplying the tcpO(2) with the mean oxygen solubility coefficient of the skin the content of physically dissolved oxygen is obtained. The decrease of tcpO(2) in the 55- to 45-mmHg range indicates the consumption of oxygen physically dissolved and chemically bound to hemoglobin. It gave a parameter for estimating the local hemoglobin content of the skin. These values and the minimal tcpO(2) after a 5-min arterial occlusion were measured in 14 healthy subjects, in 13 patients with varicose veins, but no skin lesions, in 10 patients with CVI lesions like white atrophy and lipodermatosclerosis and in 16 CVI patients with open venous ulcers. During suprasystolic occlusion tcpO(2) at the ankle remained significantly higher in CVI patients with skin lesions than in the healthy control subjects (25.6 +/- 18.9 versus 8.0 +/- 7.0 mmHg). The steepness of the tcpO(2) decrease caused by cutaneous oxygen consumption in healthy subjects was not significantly different from the CVI patients. In contrast, the decrease of tcpO(2) at the ankle between 55 and 45 mmHg was 1.9 +/- 2.0 mmHg/s in the control group and 0.7 +/- 0.5 mmHg/s in the group with open venous ulcers. These results indicate a higher hemoglobin content in the skin of the CVI patients than in healthy subjects. Obviously, the hemoglobin bound oxygen content in the skin of CVI patients is increased. Thus, a lack of oxygen is unlikely to be the primary reason for the development of skin lesions in CVI.
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Affiliation(s)
- M Stücker
- Department of Dermatology, Ruhr-University, Bochum, Germany
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Abstract
OBJECTIVE To investigate the effect of hyperbaric oxygen treatment (HBO) on the thrombolytic properties of endothelial cells. SETTING University hospital, Sweden. INTERVENTIONS Human endothelial cells were derived from saphenous veins, and exposed to oxygen in a compression chamber at 2.5 atmospheres absolute (ATA, =250kPa). Cells exposed to 2.5 ATA with a gas mixture similar to air (HB Air), and unpressurised air-exposed cells served as controls. MAIN OUTCOME MEASURES Tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type-1 (PAI-1). RESULTS Immediately after treatment there was a significant increase in t-PA protein in the medium in cultures treated with HBO compared with HB Air (p = 0.015, n = 6), and untreated controls (p = 0.015, n = 6). The PAI-1 concentration in media was also higher in the HBO-treated group compared with HB Air (p = 0.004, n = 6) and untreated controls (p = 0.004, n = 6). Six hours after treatment there was still a significant increase in PAI-1 in the HBO-treated group compared with untreated controls (p = 0.007, n = 6), but not with the pressure control. t-PA concentrations were similar. Specific mRNA for t-PA and PAI-1 was detectable immediately after treatment and six hours later in all experimental groups as assessed by reverse transcriptase polymerase chain reaction (RT-PCR). HBO increased the gene expression for both t-PA and PAI-1. CONCLUSIONS HBO affects endothelial cell function and its fibrinolytic response. These findings may have clinical relevance in hyperbaric medicine and trauma care.
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Affiliation(s)
- J Tjärnström
- Department of Surgery, Sahlgrenska University Hospital, Göteborg University, Sweden
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Abstract
Brazilian plants are potential sources of useful edible and medicinal plants. Hydromethanolic extracts prepared from 54 medicinal plants used in folk medicine to treat infections were screened for antiviral properties against five different viruses (HSV-1, HSV-2, poliovirus type 2, adenovirus type 2 and VSV). Fifty-two percent of the plant extracts exhibited antiviral against one or more tested viruses. More specifically, 42.6% showed activity against HSV-1 (herpes simplex virus type 1), 42.6% against HSV-2 (herpes simplex virus type 2), 26% against poliovirus and 24% against VSV (vesicular stomatitis virus). None of the extracts was active against adenovirus. Trixis praestans (Vell.) Cabr. and Cunila spicata Benth. extracts were further characterized for antiviral activity.
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Affiliation(s)
- C M Simões
- Department of Pharmaceutical Sciences, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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Falkenberg M. [It's time physicians start to weigh and measure! Large waist-measurements are independent risk factors]. Lakartidningen 1999; 96:3047. [PMID: 10418244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Falkenberg M. [Drug therapy of obesity will come later]. Lakartidningen 1999; 96:2582-3. [PMID: 10388276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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