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3. Immediate increase of cardiac output after percutaneous mitral valve repair (PMVR) determined by echocardiographic and invasive parameters: Patzelt: Increase of cardiac output after PMVR

Author

Patzelt, Johannes, Zhang, Yingying, Magunia, Harry, Jorbenadze, Rezo, Droppa, Michal, Ulrich, Miriam, Cai, Shanglang, Lausberg, Henning, Walker, Tobias, Wengenmayer, Tobias, Rosenberger, Peter, Schreieck, Juergen, Seizer, Peter, Gawaz, Meinrad, and Langer, Harald F.

Published
2017
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4. Effects of Mechanical Ventilation on Heart Geometry and Mitral Valve Leaflet Coaptation During Percutaneous Edge-to-Edge Mitral Valve Repair

Author

Patzelt, Johannes, Zhang, Yingying, Seizer, Peter, Magunia, Harry, Henning, Andreas, Riemlova, Veronika, Patzelt, Tara A.E., Hansen, Marc, Haap, Michael, Riessen, Reimer, Lausberg, Henning, Walker, Tobias, Reutershan, Joerg, Schlensak, Christian, Grasshoff, Christian, Simon, Dan I., Rosenberger, Peter, Schreieck, Juergen, Gawaz, Meinrad, and Langer, Harald F.

Published
2016
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14. The sheep as a pre-clinical model for testing intra-aortic percutaneous mechanical circulatory support devices

Author

Weisskopf, Miriam; https://orcid.org/0000-0001-6012-3051, Kron, Mareike, Giering, Tobias, Walker, Tobias, Cesarovic, Nikola; https://orcid.org/0000-0001-6744-2928, Weisskopf, Miriam; https://orcid.org/0000-0001-6012-3051, Kron, Mareike, Giering, Tobias, Walker, Tobias, and Cesarovic, Nikola; https://orcid.org/0000-0001-6744-2928

Abstract

The save deployment of intra-aortic percutaneous mechanical circulatory support devices is highly dependent on the inner aortic diameter. Finding the anatomically and ethically most suitable animal model for performance testing of new pMCS devices remains challenging. For this study, an ovine model using adult ewes of a large framed breed (Swiss White Alpine Sheep) was developed to test safety, reliability, and biocompatibility of catheter-mounted mechanical support devices placed in the descending thoracic aorta. Following the drawback of fluctuating aortic diameter and device malfunction in the first four animals, the model was improved by stenting the following animals with an aortic stent. Stenting the animals with an intra-aortic over the balloon stent was found to standardize the experimental set-up and to avoid early termination of the experiment due to non-device related issues. Keywords: 3R; Mechanical circulatory support; animal model; preclinical study; sheep; thoracic aorta

Published
2021

32. The challenge to verify ceramide's role of apoptosis induction in human cardiomyocytes - a pilot study

Author

Voth Vladimir, Walker Tobias, Artunc Ferruh, Mustafi Migdat, Usta Engin, Aebert Hermann, and Ziemer Gerhard

Subjects
Surgery, RD1-811, Anesthesiology, RD78.3-87.3
Abstract

Abstract Background Cardioplegia and reperfusion of the myocardium may be associated with cardiomyocyte apoptosis and subsequent myocardial injury. In order to establish a pharmacological strategy for the prevention of these events, this study aimed to verify the reliability of our human cardiac model and to evaluate the pro-apoptotic properties of the sphingolipid second messenger ceramide and the anti-apoptotic properties of the acid sphingomyelinase inhibitor amitryptiline during simulated cardioplegia and reperfusion ex vivo. Methods Cardiac biopsies were retrieved from the right auricle of patients undergoing elective CABG before induction of cardiopulmonary bypass. Biopsies were exposed to ex vivo conditions of varying periods of cp/rep (30/10, 60/20, 120/40 min). Groups: I (untreated control, n = 10), II (treated control cp/rep, n = 10), III (cp/rep + ceramide, n = 10), IV (cp/rep + amitryptiline, n = 10) and V (cp/rep + ceramide + amitryptiline, n = 10). For detection of apoptosis anti-activated-caspase-3 and PARP-1 cleavage immunostaining were employed. Results In group I the percentage of apoptotic cardiomyocytes was significantly (p < 0.05) low if compared to group II revealing a time-dependent increase. In group III ceramid increased and in group IV amitryptiline inhibited apoptosis significantly (p < 0.05). In contrast in group V, under the influence of ceramide and amitryptiline the induction of apoptosis was partially suppressed. Conclusion Ceramid induces and amitryptiline suppresses apoptosis significantly in our ex vivo setting. This finding warrants further studies aiming to evaluate potential beneficial effects of selective inhibition of apoptosis inducing mediators on the suppression of ischemia/reperfusion injury in clinical settings.

Published
2011
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35. Comparison of Deep Sedation With General Anesthesia in Patients Undergoing Percutaneous Mitral Valve Repair

Author

Patzelt, Johannes, primary, Ulrich, Miriam, additional, Magunia, Harry, additional, Sauter, Reinhard, additional, Droppa, Michal, additional, Jorbenadze, Rezo, additional, Becker, Annika S., additional, Walker, Tobias, additional, von Bardeleben, Ralph Stephan, additional, Grasshoff, Christian, additional, Rosenberger, Peter, additional, Gawaz, Meinrad, additional, Seizer, Peter, additional, and Langer, Harald F., additional

Published
2017
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37. Improved mitral valve coaptation and reduced mitral valve annular size after percutaneous mitral valve repair (PMVR) using the MitraClip system

Author

Patzelt, Johannes, primary, Zhang, Yingying, additional, Magunia, Harry, additional, Ulrich, Miriam, additional, Jorbenadze, Rezo, additional, Droppa, Michal, additional, Zhang, Wenzhong, additional, Lausberg, Henning, additional, Walker, Tobias, additional, Rosenberger, Peter, additional, Seizer, Peter, additional, Gawaz, Meinrad, additional, and Langer, Harald F, additional

Published
2017
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39. Percutaneous Transfemoral Tricuspid Valve Edge-to-Edge Repair

Author

Müller, Karin, primary, Jorbenadze, Rezo, additional, Walker, Tobias, additional, Schüler, Robert, additional, Hammerstingl, Christoph, additional, Schlensak, Christian, additional, Gawaz, Meinrad, additional, Langer, Harald F., additional, and Seizer, Peter, additional

Published
2017
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40. Extracorporeal life support prior to left ventricular assist device implantation leads to improvement of the patients INTERMACS levels and outcome

Author

Schibilsky, David, primary, Haller, Christoph, additional, Lange, Bruno, additional, Schibilsky, Barbara, additional, Haeberle, Helene, additional, Seizer, Peter, additional, Gawaz, Meinrad, additional, Rosenberger, Peter, additional, Walker, Tobias, additional, and Schlensak, Christian, additional

Published
2017
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43. Hemocompatibility testing according to ISO 10993-4: Discrimination between pyrogen- and device-induced hemostatic activation

Author

Stang, Katharina, Krajewski, Stefanie, Neumann, Bernd, Kurz, Julia, Post, Marcell, Stoppelkamp, Sandra, Fennrich, Stefan, Avci-Adali, Meltem, Armbruster, Doris, Schlensak, Christian, Burgener, Iwan Anton, Wendel, Hans Peter, Walker, Tobias, LS Interne geneeskunde, and LS Interne geneeskunde

Subjects
Lipopolysaccharides, Materials science, LPS, Lipopolysaccharide, Hemocompatibility Testing, COAGULATION, Biocompatible Materials, Bioengineering, chemical and pharmacologic phenomena, LIPOPOLYSACCHARIDE, Pharmacology, Hemolysis, Hemocompatibility, COMPLEMENT, Biomaterials, chemistry.chemical_compound, FEVER, Materials Testing, Surface contamination, WHOLE-BLOOD, Platelet, Platelet activation, ENDOTOXIN CONTAMINATION, EXTRACORPOREAL-CIRCULATION, Whole blood, Hemostasis, Bacteria, Equipment Safety, Pyrogens, Zymosan, Extracorporeal circulation, hemic and immune systems, Blood Physiological Phenomena, PLATELETS, ISO 10993-4, INTRAVASCULAR STENTS, chemistry, Mechanics of Materials, Immunology, Medical devices, Lipoteichoic acid
Abstract

Next to good hemocompatibility performance of new medical devices, which has to be tested according to the ISO 10993-4, the detection of pyrogen-contaminated devices plays a pivotal role for safe device application. During blood contact with pyrogen-contaminated devices, intense inflammatory and hemostatic reactions are feared. The aim of our study was to investigate the influence of pyrogenic contaminations on stents according to the ISO 10993-4. The pyrogens of different origins like lipopolysaccharides (LPS), purified lipoteichoic acid (LTA) or zymosan were used. These pyrogens were dried on stents or dissolved and circulated in a Chandler-loop model for 90 min at 37 degrees C with human blood. Before and after circulation, parameters of the hemostatic system including coagulation, platelets, complement and leukocyte activation were investigated. The complement system was activated by LPS isolated from Klebsiella pneumoniae and Pseudomonas aeruginosa and by LTA. Leukocyte activation was triggered by LPS isolated from K. pneumoniae, LTA and zymosan, whereas coagulation and platelet activation were only slightly influenced. Our data indicate that pyrogen-contaminated devices lead to an alteration in the hemostatic response when compared to depyrogenized devices. Therefore, pyrogenicity testing should be performed prior to hemocompatibility tests according to ISO 10993-4 in order to exclude hemostatic activation induced by pyrogen contaminations. (C) 2014 Elsevier B.V. All rights reserved.

Published
2014

44. New basic approach to treat non-small cell lung cancer based on RNA-interference

Author

Makowiecki, Christina, Nolte, Andrea, Sutaj, Besmire, Keller, Timea, Avci-Adali, Meltem, Stoll, Heidi, Schlensak, Christian, Wendel, Hans Peter, and Walker, Tobias

Subjects
Original Articles
Abstract

To date the therapy for non-small cell lung cancer (NSCLC) is associated with severe side effects, frustrating outcomes, and does not consider different tumor characteristics. The RNA-interference (RNAi) pathway represents a potential new approach to treat NSCLC. With small interfering ribonucleic acids (siRNAs), it is possible to reduce the expression of proliferation-dependent proteins in tumor cells, leading to their apoptosis. We propose that siRNAs could be adapted to the tumor type and may cause fewer side effects than current therapy.Four NSCLC cell lines were cultured under standard conditions and transfected with three different concentrations of siRNAs targeted against the hypoxia-inducible factors 1α and 2α (HIF1α and HIF2α) and signal transducer and activator of transcription 3 (STAT3). The expression was observed by quantitative real-time polymerase chain reaction and western blots. For the analysis of cell growth three days after transfection, the cell number was detected using a CASY cell counter system.The results of the silencing of the analyzed factors differ in each cell line. Cell growth was significantly reduced in all cell lines after transfection with HIF1α- and STAT3-siRNA. The silencing of HIF2α resulted in a significant effect on cell growth in squamous, and large-cell lung cancer.This study shows that the knockdown and viability to siRNA transfection differ in each tumor type according to the used siRNA. This implies that the tumor types differ among themselves and should be treated differently. Therefore, the authors suggest a possible approach to a more personalized treatment of NSCLC.

Published
2014

45. Impella 5.0 as a Second‐Line Mechanical Circulatory Support Strategy After Extracorporeal Life Support

Author

Schibilsky, David, primary, Kruger, Tobias, additional, Lausberg, Henning F., additional, Eisenlohr, Christoph, additional, Haller, Christoph, additional, Nemeth, Attila, additional, Schibilsky, Barbara, additional, Haeberle, Helene, additional, Rosenberger, Peter, additional, Walker, Tobias, additional, and Schlensak, Christian, additional

Published
2016
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49. Improved mitral valve coaptation and reduced mitral valve annular size after percutaneous mitral valve repair (PMVR) using the MitraClip system.

Author

Patzelt, Johannes, Yingying Zhang, Magunia, Harry, Ulrich, Miriam, Jorbenadze, Rezo, Droppa, Michal, Zhang, Wenzhong, Lausberg, Henning, Walker, Tobias, Rosenberger, Peter, Seizer, Peter, Gawaz, Meinrad, and Langer, Harald F.

Subjects
ECHOCARDIOGRAPHY, PROSTHETIC heart valves, MITRAL valve, MITRAL valve insufficiency, POSTOPERATIVE period, TREATMENT effectiveness, PREOPERATIVE period, PHYSIOLOGY
Abstract

Aims Improved mitral valve leaflet coaptation with consecutive reduction of mitral regurgitation (MR) is a central goal of percutaneous mitral valve repair (PMVR) with the MitraClip® system. As influences of PMVR on mitral valve geometry have been suggested before, we examined the effect of the procedure on mitral annular size in relation to procedural outcome. Methods and Results Geometry of the mitral valve annulus was evaluated in 183 patients undergoing PMVR using echocardiography before and after the procedure and at follow-up. Mitral valve annular anterior-posterior (ap) diameter decreased from 34.0 ± 4.3 to 31.3 ± 4.9 mm (P < 0.001), and medio-lateral (ml) diameter from 33.2 ± 4.8 to 32.4 ± 4.9 mm (P < 0.001). Accordingly, we observed an increase in MV leaflet coaptation after PMVR. The reduction of mitral valve ap diameter showed a significant inverse correlation with residual MR. Importantly, the reduction of mitral valve ap diameter persisted at follow-up (31.3 ± 4.9 mm post PMVR, 28.4 ± 5.3 mm at follow-up). Conclusion This study demonstrates mechanical approximation of both mitral valve annulus edges with improved mitral valve annular coaptation by PMVR using the MitraClip® system, which correlates with residual MR in patients with MR. [ABSTRACT FROM AUTHOR]

Published
2018
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50. Die siRNA-modulierte Suppression spezifischer Proteine führt zu einer reduzierten Viabilität von Malignen Pleuramesotheliom-Zelllinien

Author

Walker, Tobias, Nolte, Andrea, Usenbenz, Jana, Kobba, Joseph, Steger, Volker, Schlensak, Christian, and Wendel, Hans-Peter

Subjects
ddc: 610, 610 Medical sciences, Medicine
Abstract

Zielsetzung: Die Inzidenz des malignen Pleuramesothelioms steigt trotz der bekannten Risikofaktoren und entsprechender Prophylaxe bis heute an; dies aufgrund der langen Latenzzeit. Verschiedenartige Therapiekonzepte auch mit radikaler Chirurgie wurden vorangetrieben, dennoch bleibt die Prognose ernüchternd[for full text, please go to the a.m. URL], 21. Jahrestagung der Deutschen Gesellschaft für Thoraxchirurgie

Published
2012

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