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Lewetag RD, Nimani S, Alerni N, Hornyik T, Jacobi SF, Moss R, Menza M, Pilia N, Walz TP, HajiRassouliha A, Perez-Feliz S, Zehender M, Seemann G, Zgierski-Johnston CM, Lopez R, Odening KE. Mechano-electrical interactions and heterogeneities in wild-type and drug-induced long QT syndrome rabbits. J Physiol 2023. [PMID: 37082830 DOI: 10.1113/jp284604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 02/27/2023] [Accepted: 04/18/2023] [Indexed: 04/22/2023] Open
Abstract
BACKGROUND Electromechanical reciprocity - comprising electro-mechanical (EMC) and mechano-electric coupling (MEC) - provides cardiac adaptation to changing physiological demands. Understanding electromechanical reciprocity and its impact on function and heterogeneity in pathological conditions - such as (drug-induced) acquired long QT syndrome (aLQTS) - might lead to novel insights in arrhythmogenesis. Our aim is to investigate how electrical changes impact on mechanical function (EMC) and vice versa (MEC) under physiological conditions and in aLQTS. METHODS To measure regional differences in EMC and MEC in vivo, we used tissue phase mapping cardiac MRI and 24-lead ECG vest in healthy (control) and IKr -blocker E-4031-induced aLQTS rabbit hearts. MEC was studied in vivo by acutely increasing cardiac preload, and ex vivo by using voltage optical mapping in beating hearts at different preloads. RESULTS In aLQTS, electrical repolarization (heart rate corrected RT-interval, RTn370) was prolonged compared to control (p<0.0001) with increased spatial and temporal RT heterogeneity (p<0.01). Changing electrical function (in aLQTS) resulted in significantly reduced diastolic mechanical function and prolonged contraction duration (EMC), causing increased apico-basal mechanical heterogeneity. Increased preload acutely prolonged RTn370 in both control and aLQTS hearts (MEC). This effect was more pronounced in aLQTS (p<0.0001). Additionally, regional RT-dispersion increased in aLQTS. Motion-correction allowed to determine APD-prolongation in beating aLQTS hearts, but limited motion correction accuracy upon preload-changes prevented a clear analysis of MEC ex vivo. CONCLUSION Mechano-induced RT-prolongation and increased heterogeneity were more pronounced in aLQTS than in healthy hearts. Acute MEC effects may play an additional role in LQT-related arrhythmogenesis, warranting further mechanistic investigations. KEY POINT SUMMARY Electromechanical reciprocity - comprising excitation-contraction coupling (EMC) and mechano-electric feedback loops (MEC) - is essential for physiological cardiac function. Alterations in electrical and/or mechanical heterogeneity are known to have potentially pro-arrhythmic effects. In this study, we aimed to investigate how electrical changes impact on the mechanical function (EMC) and vice versa (MEC) - both under physiological conditions (control) and in acquired long QT syndrome (aLQTS). We show that changing the electrical function (in aLQTS) results in significantly altered mechanical heterogeneity via EMC and - vice versa - that increasing the preload acutely prolongs repolarization duration and increases electrical heterogeneity, particularly in aLQTS as compared to control. Our results substantiate the hypothesis that LQTS is an 'electro-mechanical' - rather than a 'purely electrical' - disease and suggest that acute MEC effects may play an additional role in LQT-related arrhythmogenesis. Abstract figure legend Electromechanical reciprocity in healthy (control) and acquired long QT syndrome (aLQTS) rabbit hearts. A.-B. Electrical alteration in aLQTS. A. Exemplary ECG traces demonstrating IKr -blocker E-4031-induced RT prolongation in aLQTS. B. Visualization of heart rate corrected RTn370 (each color-coded scale includes 20ms) on rabbits' torso in aLQTS compared to control (n = 6 each). C. Electro-mechanical coupling (EMC). Exemplary myocardial longitudinal velocity curve in base (cm/s) during cardiac cycle in control (blue) and aLQTS (red). Indicated are peak amplitudes (AMPsys, AMPdia) and time-to-diastolic peak (TTPdia). D. Mechano-electrical coupling (MEC). Box plots of preload induced changes in repolarization. Comparison between the timepoints baseline (15 sec before increase in preload) and time of the maximal RTn370 increase peak-preload (around 20 sec after NaCl bolus injection). Heart rate corrected RTn370 demonstrates more pronounced RT-changes in aLQTS compared to control (n = 13 each). This article is protected by copyright. All rights reserved.
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Affiliation(s)
- R D Lewetag
- Department of Cardiology and Angiology I, University Heart Center Freiburg, University Medical Center Freiburg, Freiburg, Germany
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - S Nimani
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
| | - N Alerni
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
| | - T Hornyik
- Department of Cardiology and Angiology I, University Heart Center Freiburg, University Medical Center Freiburg, Freiburg, Germany
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
| | - S F Jacobi
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Congenital Heart Defects and Pediatric Cardiology, University Heart Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - R Moss
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institute EMI, Freiburg, Germany
| | - M Menza
- Department of Radiology, Medical Physics, University Hospital Freiburg, and Faculty of Medicine, University of Freiburg, Germany
| | - N Pilia
- Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - T Puig Walz
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institute EMI, Freiburg, Germany
| | | | - S Perez-Feliz
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - M Zehender
- Department of Cardiology and Angiology I, University Heart Center Freiburg, University Medical Center Freiburg, Freiburg, Germany
| | - G Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - C M Zgierski-Johnston
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg - Bad Krozingen and Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - R Lopez
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
| | - K E Odening
- Department of Cardiology and Angiology I, University Heart Center Freiburg, University Medical Center Freiburg, Freiburg, Germany
- Translational Cardiology, Department of Cardiology and Department of Physiology, University Hospital Bern, Bern, Switzerland
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Nimani S, Hornyik T, Alerni N, Lewetag R, Giammarino L, Perez-Feliz S, Matas L, Moss KR, Zehender M, Brunner M, Seemann G, Odening KE. Differences in extent of mechano-induced QT-changes in SQTS, WT and LQTS rabbit models. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.3213] [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] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Background
Electro-mechanical (EMC) and mechano-electrical coupling (MEC) are essential for normal cardiac function. Alterations in these can result in increased arrhythmia formation. In “electrical” cardiac diseases, long-QT and short-QT syndrome, regional mechanical function is altered via EMC.
Purpose
In this study, we aimed to investigate how acute changes in mechanics may impact on electrical function (MEC) in these diseases.
Methods
To determine how acute changes in preload impact on QT duration, adult rabbits of both sexes were given a 6ml/kg BW bolus of 0.9% NaCl IV and 12-lead-ECGs were assessed first in wildtype (WT) and acquired drug-induced (E4031 to block IKr) LQT2 (“aLQT2”) rabbits, and in a second step in transgenic short-QT type 1 (“SQT1”, KCNH2-N588K) and WT littermate control rabbits (“WT-LMC”).
Results
At baseline, aLQT2 rabbits demonstrated a markedly prolonged heart-rate corrected QTc duration compared to WT (p<0.0001; n=13), with increased QT-dispersion (QTMax-Min [ms], WT 21.4±5.7 vs. aLQT2 25.8±5.8; p=0.003; n=13) and increased short-term variability of QT (STVQT [ms], WT 3.5±1.0 vs. aLQT2 5.3±1.7; p=0.02; n=13), markers for regional and temporal heterogeneity of repolarization, respectively. SQT1 rabbits (n=8) demonstrated a shorter QTc duration compared to WT-LMC (n=10; p=0.04), with no differences in QT-dispersion and STVQT between the two groups.
Increased preload acutely prolonged QT and heart-rate corrected QTc in all groups (despite a slight increase in heart-rate by an average of 25 beats/min): in WT [ms] 171.6±11.6 to 213.3±20.3 (p<0.0001) vs. aLQT2 208.9±19.6 to 271.0±37.5 (p<0.0001; n=13 each), and in WT-LMC 171.3±4.8 to 199.2±5.4 (p<0.0001; n=10) vs. SQT1 156.0±4.7 to 177.3±3.5 (p=0.0004; n=8). Importantly, the extent of mechano-induced electrical changes differed among genotypes, with less pronounced QTc prolongation in SQT1 compared to WT-LMC (delta QTc [ms], SQT1 21.2±3.4 (n=8) vs. WT-LMC 27.9±2.8 (n=10; p=0.15)), and a more pronounced QTc prolongation in aLQT2 compared to WT (delta QTc [ms], WT 41.6±14.9 vs. aLQT2 62.1±32.1; p=0.006; n=13 each). Moreover, QT-dispersion was increased significantly upon global mechanical change only in aLQTS (QTMax-Min [ms], 25.8±5.5 to 32.7±12.3; p=0.03; n=13).
Conclusion
Acute changes in mechanical function result in electrical changes via MEC in SQT1, WT and aLQT2 rabbits. The extent of these changes, however, depends on the underlying QTc duration, with the least pronounced QTc prolongation in SQT1 rabbits, with the shortest QTc, and the most pronounced QTc prolongation in aLQT2 rabbits, with the longest QTc. The most pronounced MEC effects on global QT duration as well as on regional QT dispersion in aLQT2 indicate that acute MEC effects may play an additional role in LQTS-related arrhythmogenesis.
Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): German Research Foundation (DFG) andSwiss National Science Foundation (SNF)
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Affiliation(s)
- S Nimani
- University of Bern, Translational Cardiology, Dep. of Cardiology and Dep. of Physiology, Bern, Switzerland
| | - T Hornyik
- University of Bern, Translational Cardiology, Dep. of Cardiology and Dep. of Physiology, Bern, Switzerland
| | - N Alerni
- University of Bern, Translational Cardiology, Dep. of Cardiology and Dep. of Physiology, Bern, Switzerland
| | - R Lewetag
- University of Freiburg, Dep. of Cardiology and Angiology I, Freiburg, Germany
| | - L Giammarino
- University of Bern, Translational Cardiology, Dep. of Cardiology and Dep. of Physiology, Bern, Switzerland
| | - S Perez-Feliz
- University of Freiburg, Dep. of Cardiology and Angiology I, Freiburg, Germany
| | - L Matas
- University of Bern, Translational Cardiology, Dep. of Cardiology and Dep. of Physiology, Bern, Switzerland
| | - K R Moss
- University of Freiburg, Inst. for Experimental Cardiovascular Medicine, Freiburg, Germany
| | - M Zehender
- University of Freiburg, Dep. of Cardiology and Angiology I, Freiburg, Germany
| | - M Brunner
- University of Freiburg, Dep. of Cardiology and Angiology I, Freiburg, Germany
| | - G Seemann
- University of Freiburg, Inst. for Experimental Cardiovascular Medicine, Freiburg, Germany
| | - K E Odening
- University of Bern, Translational Cardiology, Dep. of Cardiology and Dep. of Physiology, Bern, Switzerland
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Lewetag R, Hornyik T, Jacobi S, Moss R, Pilia N, Menza M, Perez-Feliz S, Bode C, Seemann G, Odening KE. Electro-mechanical and mechano-electrical interactions in healthy and drug-induced LQTS rabbit hearts. Europace 2021. [DOI: 10.1093/europace/euab116.578] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Foundation. Main funding source(s): German Research Foundation
Background
Electrical and mechanical heterogeneities and their interactions (electro-mechanical and mechano-electrical coupling; EMC / MEC) are essential for normal cardiac function. Alterations in these can result in increased arrhythmia formation.
Purpose
With this study, we aim to investigate EMC and MEC under physiological and pathological conditions to better understand their roles in arrhythmia development.
Methods
Multi-channel ECG and TPM-MRI were used to measure regional differences in EMC in healthy ("control") and IKr-blocker E-4031 induced acute LQTS ("E-4031") rabbit hearts in vivo. MEC was studied in both groups by acutely changing mechanical function (increased preload by 6 ml/kg BW bolus of NaCl).
Results
In acute LQTS hearts (E-4031 10µg/kg bolus + 1µg/(kg*min) iv), cardiac repolarization was markedly prolonged compared to healthy controls, (p < 0.0001; n = 13), with increased QT-dispersion (Max-Min), a marker for regional heterogeneity of repolarization (p < 0.01; n = 13).
Changing electrical function by E-4031 resulted in changes of mechanical features (EMC): in acute LQTS hearts, diastolic longitudinal velocity (Vz) was reduced in all basal (p = 0.003; n = 19) and 4/6 mid segments (p = 0.006; n = 19). Longitudinal diastolic TTP was prolonged significantly in 5/6 basal and 4/6 mid segments by E-4031. These alterations led to an increased apicobasal heterogeneity of longitudinal contraction duration (basal-apical Vz_dia_TTP [ms] 2.9 ± 10.6 vs. 21.1 ± 21.3; p = 0.01; n = 9).
Increased preload acutely prolonged QTc in both "control" and "E-4031" hearts (‘control’ 156.6 ± 11.6 to 198.3 ± 20.3; p < 0.0001 vs. ‘E-4031’ 193.9 ± 19.6 to 256.0 ± 37.5; p < 0.0001; n = 13) (MEC). This effect was more pronounced in "E-4031" acute LQTS hearts than in healthy hearts (Figure 1; delta QTc [ms] ‘control’ 41.6 ± 14.9 vs. ‘E4031’ 62.1 ± 32.1; p < 0.006, n = 13). QT-dispersion (Max-Min) was increased significantly upon mechanical change only in "E-4031" (‘E-4031’ 25.8 ± 5.5 to 32.7 ± 12.3; p < 0.03, n = 13).
Conclusion
E-4031-induced changes in electrical function resulted in marked alterations in mechanical features via EMC. Similarly, acute changes in mechanical function (increased preload) resulted in electrical changes via MEC. Importantly, QT-prolonging effects of acutely increased preload, as well as its effects on regional heterogeneity of repolarization, were more pronounced in E-4031-induced acute LQTS hearts, indicating that cardiac repolarization in LQTS may be more susceptible to acute MEC effects than in healthy hearts. Acute MEC effects may thus play an additional role in LQT-related arrhythmogenesis. Abstract Figure.
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Affiliation(s)
- R Lewetag
- University Heart Center Freiburg, Department of Cardiology and Angiology I, Freiburg, Germany
| | - T Hornyik
- Bern University Hospital, Inselspital, Department of Cardiology and Department of Physiology, Bern, Switzerland
| | - S Jacobi
- University Heart Center Freiburg, Department of Pediatric Cardiology, Freiburg, Germany
| | - R Moss
- University Heart Center Freiburg, Institute for Experimental Cardiovascular Medicine, Freiburg, Germany
| | - N Pilia
- Karlsruhe Institute of Technology (KIT), Institute of Biomedical Engineering, Karlsruhe, Germany
| | - M Menza
- University Hospital of Freiburg, Department of Radiology, Freiburg, Germany
| | - S Perez-Feliz
- University Heart Center Freiburg, Institute for Experimental Cardiovascular Medicine, Freiburg, Germany
| | - C Bode
- University Heart Center Freiburg, Department of Cardiology and Angiology I, Freiburg, Germany
| | - G Seemann
- University Heart Center Freiburg, Institute for Experimental Cardiovascular Medicine, Freiburg, Germany
| | - KE Odening
- Bern University Hospital, Inselspital, Department of Cardiology and Department of Physiology, Bern, Switzerland
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Rog-Zielinska EA, Moss R, Kaltenbacher W, Greiner J, Verkade P, Seemann G, Kohl P, Cannell MB. Nano-scale morphology of cardiomyocyte t-tubule/sarcoplasmic reticulum junctions revealed by ultra-rapid high-pressure freezing and electron tomography. J Mol Cell Cardiol 2021; 153:86-92. [PMID: 33359037 PMCID: PMC8035077 DOI: 10.1016/j.yjmcc.2020.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 11/27/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022]
Abstract
Detailed knowledge of the ultrastructure of intracellular compartments is a prerequisite for our understanding of how cells function. In cardiac muscle cells, close apposition of transverse (t)-tubule (TT) and sarcoplasmic reticulum (SR) membranes supports stable high-gain excitation-contraction coupling. Here, the fine structure of this key intracellular element is examined in rabbit and mouse ventricular cardiomyocytes, using ultra-rapid high-pressure freezing (HPF, omitting aldehyde fixation) and electron microscopy. 3D electron tomograms were used to quantify the dimensions of TT, terminal cisternae of the SR, and the space between SR and TT membranes (dyadic cleft). In comparison to conventional aldehyde-based chemical sample fixation, HPF-preserved samples of both species show considerably more voluminous SR terminal cisternae, both in absolute dimensions and in terms of junctional SR to TT volume ratio. In rabbit cardiomyocytes, the average dyadic cleft surface area of HPF and chemically fixed myocytes did not differ, but cleft volume was significantly smaller in HPF samples than in conventionally fixed tissue; in murine cardiomyocytes, the dyadic cleft surface area was higher in HPF samples with no difference in cleft volume. In both species, the apposition of the TT and SR membranes in the dyad was more likely to be closer than 10 nm in HPF samples compared to CFD, presumably resulting from avoidance of sample shrinkage associated with conventional fixation techniques. Overall, we provide a note of caution regarding quantitative interpretation of chemically-fixed ultrastructures, and offer novel insight into cardiac TT and SR ultrastructure with relevance for our understanding of cardiac physiology.
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Affiliation(s)
- E A Rog-Zielinska
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - R Moss
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - W Kaltenbacher
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - J Greiner
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - P Verkade
- School of Biochemistry, Faculty of Biomedical Sciences, University of Bristol, Bristol, UK
| | - G Seemann
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - P Kohl
- Institute for Experimental Cardiovascular Medicine, University Heart Center Freiburg·Bad Krozingen, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - M B Cannell
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK.
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Schwalm AK, Metzger-Boddien C, Seemann G, Mandl J, Obiegala A, Pfeffer M, Sting R. Field study on bovine paratuberculosis using real-time PCR and liquid culture for testing environmental and individual fecal samples implemented in dairy cow management. J Dairy Sci 2019; 102:11260-11267. [PMID: 31563316 DOI: 10.3168/jds.2018-15649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 08/21/2019] [Indexed: 12/17/2022]
Abstract
Bovine paratuberculosis (Johne's disease) is a bacterial, chronic, and wasting intestinal disease caused by Mycobacterium avium ssp. paratuberculosis (MAP). Johne's disease causes severe losses in dairy farm productivity and is also suspected to be a potential trigger for Crohn's disease in humans. The fecal-oral infection of MAP to neonates is recognized as an important within-herd transmission route. Our objective was to recommend diagnostic methods for herds with suspected paratuberculosis requiring fast results, as well as for herds with breeding programs or others that aim at being nonsuspected of paratuberculosis infection. We determined a period of 8 wk from sampling to diagnostic findings suitable for testing of cows during the dry period. We therefore tested environmental and individual fecal samples with one rapid and one highly sensitive diagnostic method. Environmental samples (boot swabs) were taken as a first step in 3 herds and tested using a DNA extraction protocol for feces and subsequent real-time PCR (referred to as fecal PCR). Additionally, cultivation in liquid medium for 6 wk was performed and verified with real-time PCR (referred to as liquid culture). Automation of DNA extraction based on magnetic beads and the PCR setup was performed with pipetting robots. As a result, we successfully detected MAP in boot swabs of all herds by both methods. In a second step, 245 individual fecal samples from the 3 herds were examined using also fecal PCR and liquid culture. The results obtained by fecal PCR were compared with detection of MAP using cultivation in liquid medium for 6 wk. Testing individual cows, we identified MAP-specific DNA in 53 fecal samples using the liquid culture. Using fecal PCR, we revealed 43 positive samples of which 39 also tested positive in the liquid culture, revealing MAP-positive cows in all 3 herds. The fecal PCR procedure allows rapid detection of MAP-specific DNA with 74% of the sensitivity of liquid culture. For the purpose of testing with maximal sensitivity, cultivation in liquid medium is recommended. Cultivation of MAP in liquid medium M7H9C means a significant time gain in comparison to cultivation on solid media, which requires twice as much time. Thus, this testing fits within the 6- to 8-wk dry period of gravid cows and provides test results before calving, a prerequisite to prevent fecal-oral transmission to newborn calves.
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Affiliation(s)
- A K Schwalm
- Chemical and Veterinary Investigations Office, Stuttgart, Fellbach D 70736, Germany.
| | | | - G Seemann
- Animal Health Service, Baden-Wuerttemberg Animal Diseases Fund, Fellbach D 70736, Germany
| | - J Mandl
- Animal Health Service, Baden-Wuerttemberg Animal Diseases Fund, Fellbach D 70736, Germany
| | - A Obiegala
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig D 04103, Germany
| | - M Pfeffer
- Institute of Animal Hygiene and Veterinary Public Health, University of Leipzig, Leipzig D 04103, Germany
| | - R Sting
- Chemical and Veterinary Investigations Office, Stuttgart, Fellbach D 70736, Germany
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Maxwell S, Wallis D, Zhou N, Baker D, Mousavi-Fard S, Loesch K, Galaviz S, Sun Q, Threadgill D, Rojas C, O'Brien M, Clubb F, Ioerger T, DeJesus M, Dong W, Seemann G, Fossum T, Sacchettini J. DEVELOPMENT OF NOVEL, NON-TOXIC RIFAMYCINS THAT REVERSE DRUG RESISTANCE IN DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL). Hematol Oncol 2017. [DOI: 10.1002/hon.2438_118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- S.A. Maxwell
- Molecular & Cellular Medicine; Texas A&M Health Science Center; College Station USA
| | - D. Wallis
- Genetics Research Division; University of Alabama; Birmingham AL USA
| | - N. Zhou
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - D. Baker
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - S. Mousavi-Fard
- Molecular & Cellular Medicine; Texas A&M Health Science Center; College Station USA
| | - K. Loesch
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - S. Galaviz
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - Q. Sun
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - D.M. Threadgill
- Molecular & Cellular Medicine; Texas A&M Health Science Center; College Station USA
| | - C.M. Rojas
- Molecular & Cellular Medicine; Texas A&M Health Science Center; College Station USA
| | - M. O'Brien
- Veterinary Medical Pathobiology; Texas A&M University, College Station; USA
| | - F.J. Clubb
- Veterinary Medical Pathobiology; Texas A&M University, College Station; USA
| | - T. Ioerger
- Computer Science; Texas A&M University, College Station; USA
| | - M. DeJesus
- Computer Science; Texas A&M University, College Station; USA
| | - W. Dong
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - G. Seemann
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
| | - T. Fossum
- Research and Strategic Initiatives; Midwestern University; Downers Grove USA
| | - J.C. Sacchettini
- Biochemistry & Biophysics; Texas A&M University, College Station; USA
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Sting R, Hrubenja M, Mandl J, Seemann G, Salditt A, Waibel S. Detection of Mycobacterium avium subsp. paratuberculosis in faeces using different procedures of pre-treatment for real-time PCR in comparison to culture. Vet J 2014; 199:138-42. [DOI: 10.1016/j.tvjl.2013.08.033] [Citation(s) in RCA: 14] [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: 06/19/2013] [Revised: 08/27/2013] [Accepted: 08/28/2013] [Indexed: 12/17/2022]
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Bauer S, Edelmann JC, Seemann G, Sachse FB, Dössel O. Estimating Intracellular Conductivity Tensors from Confocal Microscopy of Rabbit Ventricular Tissue. ACTA ACUST UNITED AC 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-N/bmt-2013-4333/bmt-2013-4333.xml. [PMID: 24043045 DOI: 10.1515/bmt-2013-4333] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Schuler S, Keller MW, Oesterlein T, Seemann G, Dössel O. Influence of Catheter Orientation, Tissue Thickness and Conduction Velocity on the Intracardiac Electrogram. ACTA ACUST UNITED AC 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-N/bmt-2013-4334/bmt-2013-4334.xml. [PMID: 24043070 DOI: 10.1515/bmt-2013-4334] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Oesterlein T, Keller M, Schuler S, Luik A, Krüger M, Seemann G, Seemann G, Schmitt C, Dössel O. Determination of local activation time in bipolar endocardial electrograms: a comparison of clinical criteria and a new method based on the non-linear energy operator. J Electrocardiol 2013. [DOI: 10.1016/j.jelectrocard.2013.05.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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11
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Moss R, Seemann G, Dössel O, Sachse FB, Tristani-Firouzi M. Adaptation of the Voltage Dependent Muscarinic M2 Receptor on Cardiac Ik,Ach to Different Ligands. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-N/bmt-2013-4332/bmt-2013-4332.xml. [DOI: 10.1515/bmt-2013-4332] [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: 11/15/2022]
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12
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Seemann G, Álvarez de Eulate M, Dössel O, Keller DUJ. Variation of Human Ventricular Iks Heterogeneities to Reconstruct Measured Multi-Channel ECG Data. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-N/bmt-2013-4319/bmt-2013-4319.xml. [DOI: 10.1515/bmt-2013-4319] [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: 11/15/2022]
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13
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Busch LM, Fritz T, Krueger MW, Seemann G, Dössel O. Impact of Different Ablation Patterns on the Biomechanics of the Human Left Atriijm. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-N/bmt-2013-4336/bmt-2013-4336.xml. [DOI: 10.1515/bmt-2013-4336] [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: 11/15/2022]
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14
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Wilhelms M, Rombach C, Scholz EP, Dossel O, Seemann G. Impact of amiodarone and cisapride on simulated human ventricular electrophysiology and electrocardiograms. Europace 2012; 14 Suppl 5:v90-v96. [DOI: 10.1093/europace/eus281] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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15
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Dorn A, Krueger MW, Seemann G, Doessel O. Modelling of heterogeneous human atrial electrophysiology. ACTA ACUST UNITED AC 2012; 57 Suppl 1:/j/bmte.2012.57.issue-s1-O/bmt-2012-4215/bmt-2012-4215.xml. [PMID: 23096331 DOI: 10.1515/bmt-2012-4215] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Wülfers EM, Torres NS, Lenis G, Li H, Seemann G, Dössel O, Bridge JHB, Sachse FB. An automated approach to analyze microstructural remodeling from confocal microscopies of ventricular myocytes from diseased hearts. BIOMED ENG-BIOMED TE 2012; 57:46-49. [DOI: 10.1515/bmt-2012-4438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- E. M. Wülfers
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA
| | - N. S. Torres
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA
| | - G. Lenis
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA
| | - H. Li
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA
| | - G. Seemann
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - O. Dössel
- Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - J. H. B. Bridge
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA
| | - F. B. Sachse
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, USA
- Department of Bioengineering, University of Utah, Salt Lake City, USA
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17
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Keller DUJ, Weiss DL, Dossel O, Seemann G. Influence of ${I_{Ks}}$ Heterogeneities on the Genesis of the T-wave: A Computational Evaluation. IEEE Trans Biomed Eng 2012; 59:311-22. [DOI: 10.1109/tbme.2011.2168397] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Krueger MW, Seemann G, Dössel O. Towards Personalized Biophysical Models of Atrial Anatomy and Electrophysiology in Clinical Environments. BIOMED ENG-BIOMED TE 2012. [DOI: 10.1515/bmt-2012-4184] [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: 11/15/2022]
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19
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Keller MW, Seemann G, Dössel O. Simulating extracellular microelectrode recordings on cardiac tissue preparations in a bidomain model. BIOMED ENG-BIOMED TE 2012; 57 Suppl 1:/j/bmte.2012.57.issue-s1-O/bmt-2012-4341/bmt-2012-4341.xml. [DOI: 10.1515/bmt-2012-4341] [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: 11/15/2022]
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20
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Wilhelms M, Holl LP, Dössel O, Seemann G. Impact of Antiarrhythmic Drugs on a Virtual Model of Atrial Fibrillation. BIOMED ENG-BIOMED TE 2012; 57 Suppl 1:/j/bmte.2012.57.issue-s1-O/bmt-2012-4196/bmt-2012-4196.xml. [DOI: 10.1515/bmt-2012-4196] [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: 11/15/2022]
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21
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Keller DUJ, Jarrousse O, Fritz T, Ley S, Dossel O, Seemann G. Impact of Physiological Ventricular Deformation on the Morphology of the T-Wave: A Hybrid, Static-Dynamic Approach. IEEE Trans Biomed Eng 2011; 58:2109-19. [DOI: 10.1109/tbme.2011.2147785] [Citation(s) in RCA: 15] [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] [Indexed: 11/10/2022]
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22
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Weber FM, Keller DUJ, Bauer S, Seemann G, Lorenz C, Dössel O. Predicting Tissue Conductivity Influences on Body Surface Potentials—An Efficient Approach Based on Principal Component Analysis. IEEE Trans Biomed Eng 2011; 58:265-73. [DOI: 10.1109/tbme.2010.2090151] [Citation(s) in RCA: 15] [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] [Indexed: 11/10/2022]
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23
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Mohr MB, G. Blümcke L, Seemann G, Sachse FB, Dössel O. MODELING OF MIYOCARDIAL DEFORMATION WITH AN EXTENDED SPRING MASS SYSTEM. BIOMED ENG-BIOMED TE 2009. [DOI: 10.1515/bmte.2003.48.s1.6] [Citation(s) in RCA: 5] [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: 11/15/2022]
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24
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Graf IM, Seemann G, Weiss DL, Dössel O. Influence of electrophysiological heterogeneity on electrical stimulation in healthy and failing human hearts. Med Biol Eng Comput 2006; 43:783-92. [PMID: 16594307 DOI: 10.1007/bf02430958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The application of strong electrical stimuli is a common method used for terminating irregular cardiac behaviour. The study presents the influence of electrophysiological heterogeneity on the response of human hearts to electrical stimulation. The human electrophysiology was simulated using the ten Tusscher-Noble-Noble-Panfilov cell model. The anisotropic propagation of depolarisation in three-dimensional virtual myocardial preparations was calculated using bidomain equations. The research was carried out on different types of virtual cardiac wedge. The selection of the modelling parameters emphasises the influence of cellular electrophysiology on the response of the human myocardium to electrical stimulation. The simulations were initially performed on a virtual cardiac control model characterised by electrophysiological homogeneity. The second preparation incorporated the transmural electrophysiological heterogeneity characteristic of the healthy human heart. In the third model type, the normal electrophysiological heterogeneity was modified by the conditions of heart failure. The main currents responsible for repolarisation (Ito, IKs and IKI) were reduced by 25%. Successively, [Na+]i was increased by the regulation of the Na+-Ca2+ exchange function, and fibrosis was represented by decreasing electrical conductivity. Various electrical stimulation configurations were used to investigate the differences in the responses of the three different models. Monophasic and biphasic electrical stimuli were applied through rectangular paddles and needle electrodes. A whole systolic period was simulated. The distribution of the transmembrane voltage indicated that the modification of electrophysiological heterogeneity induced drastic changes during the repolarisation phase. The results illustrated that each of the heart failure conditions amplifies the modification of the response of the myocardium to electrical stimulation. Therefore a theoretical model of the failing human heart must incorporate all the characteristic features.
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Affiliation(s)
- I M Graf
- Institute of Biomedical Engineering, Universität Karlsruhe (TH), Germany.
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25
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Reinerth G, Schmidt TM, Seemann G, Albers J, Doessel O, Hagl S, Vahl CF. Planning of surgical antiarrhythmic interventions based on simulations of cardiac electrophysiology. Thorac Cardiovasc Surg 2004. [DOI: 10.1055/s-2004-816762] [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: 10/19/2022]
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26
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Reinerth G, Schmidt TM, Seemann G, Albers J, Doessel O, Hagl S, Vahl CF. Simulation of biventricular activity in ventricular pacing on 3D-echocardiographic images using the cellular automaton in a porcine model. Thorac Cardiovasc Surg 2004. [DOI: 10.1055/s-2004-816581] [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: 10/19/2022]
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27
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Mrugalla HR, Samberger M, Schuhmann W, Seemann G, Vogel H. �bergabemanagement f�r Beatmungspatienten im Luftrettungsdienst. Notf Rett Med 2003. [DOI: 10.1007/s10049-003-0584-z] [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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28
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Häfner J, Sachse FB, Sansour C, Seemann G, Dössel O. Hyperelastic description of elastomechanic properties of the heart: a new material law and its application. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:770-3. [PMID: 12465299 DOI: 10.1515/bmte.2002.47.s1b.770] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Knowledge concerning passive mechanic cardiac properties is necessary to model behavior of whole hearts. Commonly, a continuum mechanics based description is chosen in conjunction with the finite element method. The aim of this work is to summarize, derive and evaluate hyperelastic material laws for inhomogeneous, anisotropic myocardium. Hence, different material laws were set up and their parameters were determined taking measurement data in literature into account. The material laws were compared from a theoretical and numerical point of view. Furthermore, the application of continuum mechanics based methods is evaluated concerning aspects of numerical solution and spatial discretisation. In further work the laws will be implemented and integrated in an existing software environment, which allows the calculation of deformations in complex geometries.
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Affiliation(s)
- J Häfner
- Institut für Biomedizinische Technik, Universität Karlsruhe (TH), Germany.
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29
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Seemann G, Reinerth G, Dössel O, Vahl CF. [Electrophysiological modeling of the heart as a basis in therapeutic interventions]. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:927-9. [PMID: 12465346 DOI: 10.1515/bmte.2002.47.s1b.927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- G Seemann
- Institut für Biomedizinische Technik, Universität Karlsruhe (TH), Deutschland.
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30
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Glänzel K, Sachse FB, Seemann G, Riedel C, Dössel O. Modeling force development in the sarcomere in consideration of electromechanical coupling. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 2:774-7. [PMID: 12465300 DOI: 10.1515/bmte.2002.47.s1b.774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Models of the cellular force development simulate the contractive behavior of the sarcomere. In conjunction with electrophysiological models they can contribute to a better comprehension of physiology and pathologies. Aim of this study is to examine the coupling of cellular electrophysiological processes and force development. For that a graphical user interface was developed to simplify the parameterization and calculation of the models as well as to present the results graphically. A feedback mechanism is introduced to pay attention to close connections between force development and intracellular processes. On basis of various tests with different boundary conditions, new force models are developed, parameterized, validated and compared with models in literature. In future studies the results will be tested in multiple cell organization.
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Affiliation(s)
- K Glänzel
- Institut für Biomedizinische Technik, Universität Karlsruhe (TH), Germany.
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31
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Abstract
Simulations of the electro-mechanical behavior of the heart improve the comprehension of the mechanisms of the cardiovascular system. In this study a left ventricular model including electrical excitation and force development is presented. The electrical model consists of a complex electrophysiological cell model and a monodomain excitation diffusion model. The force development bases on the intracellular calcium concentration and is calculated with a force model. It consists--like the electrophysiological model--of non-linear coupled differential equations. Simulations are obtained in a realistic and anisotropic model of the left ventricle of the Visible Female data set provided by the National Library of Medicine, USA. Effects to the mechanical behavior will be examined in future.
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Affiliation(s)
- G Seemann
- Institut für Biomedizinische Technik, Universität Karlsruhe (TH), Germany.
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32
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Mohr MB, Blümcke LG, Sachse FB, Seemann G, Werner CD, Dössel O. [Volume-based modeling of deformation in myocardium based on models of force development]. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 1:225-8. [PMID: 12451823] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- M B Mohr
- Institut für Biomedizinische Technik, Universität Karlsruhe (TH), Deutschland.
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Sachse FB, Blümcke LG, Mohr M, Glänzel K, Häfner J, Riedel C, Seemann G, Skipa O, Werner CD, Dössel O. Comparison of macroscopic models of excitation and force propagation in the heart. BIOMED ENG-BIOMED TE 2003; 47 Suppl 1 Pt 1:217-20. [PMID: 12451821 DOI: 10.1515/bmte.2002.47.s1a.217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Computer aided simulations of the heart provide knowledge of phenomena, which are commonly neither visible nor measurable with current techniques. This knowledge can be applied e.g. in cardiologic diagnosis and therapy. A variety of models was created to reconstruct cardiac processes, e.g. electrical propagation and force development. In this work different macroscopic models were compared, i.e. models based on excitation-diffusion equations and cellular automata. The comparison was carried out concerning reconstruct-ability of cardiac phenomena, mathematical and biophysical foundation as well as computational expense. Particularly, the reconstruct-ability of electromechanic feedback mechanisms was examined. Perspectives for further developments and improvements of models were given.
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Affiliation(s)
- F B Sachse
- Institut für Biomedizinische Technik, Universität Karlsruhe (TH), Germany.
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34
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Höper C, Seemann G, Sachse FB, Zhang H, Dössel O. 3D COMPUTER MODEL OF HUMAN ATRIAL ANATOMY AND ELECTROPHYSIOLOGY. BIOMED ENG-BIOMED TE 2003. [DOI: 10.1515/bmte.2003.48.s1.2] [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: 11/15/2022]
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35
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Seemann G, Sachse FB, Weiß DL, Dössel O. INVESTIGATION OF FIBRILLATION IN HUMAN LEFT VENTRICLE WITH A REACTION-DIFFUSION MODEL. BIOMED ENG-BIOMED TE 2003. [DOI: 10.1515/bmte.2003.48.s1.226] [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: 11/15/2022]
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36
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Chaisaowong K, Sachse F, Seemann G, Mohr M, Dössel O. MODELING OF HUMAN CARDIAC FORCE DEVELOPMENT: QUANTITATIVE DESCRIPTION FROM MYOFILAMENT TO MYOCARDIUM. BIOMED ENG-BIOMED TE 2003. [DOI: 10.1515/bmte.2003.48.s1.466] [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: 11/15/2022]
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37
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Weiß DL, Seemann G, Sachse FB, Dössel O. INVESTIGATION OF ELECTROPHYSIOLOGICAL HETEROGENEITY AND ANISOTROPY ACROSS THE HUMAN VENTRICULAR WALL. BIOMED ENG-BIOMED TE 2003. [DOI: 10.1515/bmte.2003.48.s1.228] [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: 11/15/2022]
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38
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Dössel O, Sachse FB, Seemann G, Werner CD. [Computer models of the electrophysiological properties of the heart]. BIOMED ENG-BIOMED TE 2002; 47:250-7. [PMID: 12369213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Computer models of the heart can improve the understanding of the electrophysiological processes in healthy and diseased heart. They become more and more important for detailed diagnosis of arrhythmias and for optimization of therapy. Models of myocardium cells known today are described--they are based on the properties of all relevant ion channels in the cell membrane. Then it is demonstrated, how many cells can be joined to form a cell patch and how finally the complete heart can be modelled. A simpler approach is using a so called cellular automation that allows for a significant reduction of calculation time while sacrificing some accordance to reality. Adaptive cellular automations allow for a fast simulation with acceptable accuracy. Using them some results were gained for the simulation of typical arrhythmias, in the field of validation using an animal model and for therapy planning with RF-ablation.
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Affiliation(s)
- O Dössel
- Institut für Biomedizinische Technik, Universität Karlsruhe
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39
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Mohr M, Blümcke L, Sachse F, Seemann G, Werner C, Dössel O. VOLUMENBASIERTE MODELLIERUNG DER DEFORMATION IM MYOKARD AUSGEHEND VON MODELLEN DER KRAFTENTWICKLUNG. BIOMED ENG-BIOMED TE 2002. [DOI: 10.1515/bmte.2002.47.s1a.225] [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: 11/15/2022]
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40
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Thüringer M, Sachse FB, Seemann G, Werner CD, Dössel O. SIMULATION DER DEFORMATION IM MYOKARD AUSGEHEND VON MIKROSKOPISCHEN MODELLEN DER KRAFTENTWICKLUNG UND HYPERELASTISCHEN MATERIALBESCHREIBUNGEN. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.526] [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: 11/15/2022]
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41
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Seemann G, Sachse F, Werner C, Dössel O. SIMULATION DER KRAFTENTWICKLUNG IM MYOKARD BEI PHYSIOLOGISCHER UND PATHOLOGISCHER ERREGUNGSAUSBREITUNG. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.192] [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: 11/15/2022]
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42
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Barros S, Sá Couto N, Sachse FB, Werner CD, Seemann G. SEGMENTATION AND TISSUE-CLASSIFICATION OF THE VISIBLE FEMALE DATASET - THORACIC MUSCLES, BONES AND BLOOD VESSELS. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.510] [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: 11/15/2022]
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43
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Mohr MB, Sachse FB, Seemann G, Werner CD, Dössel O. VERGLEICH VON MIKROSKOPISCHEN UND MAKROSKOPISCHEN MODELLEN DER KRAFTENTWICKLUNG UND DEFORMATION IM MYOKARD. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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44
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Jösel M, Sachse FB, Seemann G, Werner CD, Dössel O. SIMULATION DER KATHETERISIERUNG UND RADIO-FREQUENZ-ABLATION IN DER KARDIOLOGIE MIT EINEM HAPTISCHEN INTERFACE. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.528] [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: 11/15/2022]
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45
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Weiß D, Sachse F, Werner C, Seemann G, Dössel O. VERGLEICH ELEKTROPHYSIOLOGISCHER MODELLE BEI SIMULIERTEN ATRIALEN FIBRILLATIONEN. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.514] [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: 11/15/2022]
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46
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Blümcke L, Sachse F, Seemann G, Werner C, Dössel O. ENTWICKLUNG EINES SCHNELLEN VERFAHRENS ZUR DEFORMATION IM HERZEN AUSGEHEND VON MAKROSKOPISCHEN MODELLEN DER KRAFTENTWICKLUNG. BIOMED ENG-BIOMED TE 2001. [DOI: 10.1515/bmte.2001.46.s1.516] [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: 11/15/2022]
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47
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Sting R, Simmert J, Mandl J, Seemann G, Bay F, Müller KF, Schmitt K, Mentrup T. [Coxiella burnetii infections and infections with bacteria of the genus Chlamydia in dairy cattle]. Berl Munch Tierarztl Wochenschr 2000; 113:423-30. [PMID: 11153221] [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: 02/18/2023]
Abstract
Comparative studies on the prevalence of infections caused by Coxiella burnetii (C. burnetii) and Chlamydia were carried out with 592 cattle older than 2 years and 234 cattle younger than 2 years. Of these 477 originated from 24 dairy herds with considerable fertility problems (positive herds) and 349 from 14 dairy herds without major fertility problems (control herds). For the direct detection of these pathogens in the genitals capture ELISAs were employed, for the demonstration of antibodies the complement fixation test (CFT). Direct detection of C. burnetii and Chlamydia single as well as mixed infection revealed significant higher values for cattle from positive herds compared with those from the control herds. Animals revealing insemination ratios of > or = 2 showed significantly more frequent excretion of Chlamydia via the genitals and antibodies against C. burnetii than cattle with an insemination ratio of < 2. Investigations of cows which had had an abortion showed no indications of significantly more frequent C. burnetii or chlamydial infections. Inseminated but non-pregnant cows excreted significantly more C. burnetii and Chlamydia than pregnant cows. Clinical signs of endometritis were associated with an enhanced excretion of Chlamydia. Animals younger than 2 years excreted significantly more frequently C. burnetii but not Chlamydia via the genitals than animals older than 2 years. Indirect test showed results vice versa.
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Affiliation(s)
- R Sting
- Chemisches und Veterinäruntersuchungsamt Stuttgart, Sitz Fellbach, Aussenstelle Stuttgart
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48
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Hinderer A, Seemann G, Klee W. [Effect of ad lib and restricted milk feeding on the course of illness and body weight in young calves with diarrhea]. Dtsch Tierarztl Wochenschr 1999; 106:14-7. [PMID: 10028753] [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: 02/10/2023]
Abstract
Two different feeding regimens for calves (age up to 21 days) suffering from acute diarrhea were evaluated with respect to course of illness and change in body weight. The patients of the experimental group were given whole milk ad libitum three times a day. The patients of the control group were offered whole milk at a rate of 13% their body mass per day divided into three meals. In addition, both groups were offered an oral rehydration solution at a rate 9.5% of body mass per day, also divided into three portions. Data from 60 calves (30 in both groups) were available for statistical analysis. The duration of illness in the experimental group was 10.9 +/- 6.0 days vs. 10.0 +/- 5.2 days in the control group. The daily increase of body mass in the experimental group averaged 0.607 +/- 0.452 kg, the one in the control group 0.230 +/- 0.231 kg (p = 0.0002). The calves of the experimental group required 13.16 +/- 11.18 I milk per kg weight gain, the calves of the control group 21.39 +/- 12.80 I. Six calves of the experimental group and two calves of the control group subsequently had a relapse. On the basis of the results obtained, a feeding regimen for calves suffering from acute diarrhea is suggested.
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Affiliation(s)
- A Hinderer
- II. Medizinischen Tierklinik, Universität München
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Gentile A, Rademacher G, Seemann G, Klee W. [Systemic effects of ruminal acidosis following ruminal drinking in dairy calves. A retrospective analysis of 293 cases]. Tierarztl Prax Ausg G Grosstiere Nutztiere 1998; 26:205-9. [PMID: 9710922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In a retrospective study the data of 293 young calves (age upon admission less than four weeks) with evidence of ruminal drinking (rumen pH < 6.0) were analyzed for possible associations between ruminal acidosis and various parameters of systemic acid-base metabolism (blood pH, blood levels of HCO3- and L-lactate, as well as anion gap). On the basis of the degree of ruminal acidosis (pH < 5.0/ > or = 5.0) and evidence of diarrhea, the animals were assigned to one of four groups. The results indicate that severe ruminal acidosis leads to disturbances of systemic acid-base metabolism in young calves, too. With additional diarrhea, those disturbances can be complex.
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Affiliation(s)
- A Gentile
- Dipartimento Clinico Veterinario-Sezione di Medicina Interna, Universität Bologna
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Seemann G, Seiler FR, Schulz G. Laudation presented on the occasion of the bestowal of the Behring Prize to Professor Don C. Wiley. Behring Inst Mitt 1994:4 p preceding table of contents. [PMID: 7998913] [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: 05/22/2023]
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