6 results on '"Max Wacker"'
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2. Integrated biophysical matching of bacterial nanocellulose coronary artery bypass grafts towards bioinspired artery typical functions
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Jörn Hülsmann, Theresa Fraune, Baratha Dodawatta, Fabian Reuter, Martin Beutner, Viktoria Beck, Matthias Hackert-Oschätzchen, Claus Dieter Ohl, Katja Bettenbrock, Gabor Janiga, Jens Wippermann, and Max Wacker
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Medicine ,Science - Abstract
Abstract Revascularization via coronary artery bypass grafting (CABG) to treat cardiovascular disease is established as one of the most important lifesaving surgical techniques worldwide. But the shortage in functionally self-adaptive autologous arteries leads to circumstances where the clinical reality must deal with fighting pathologies coming from the mismatching biophysical functionality of more available venous grafts. Synthetic biomaterial-based CABG grafts did not make it to the market yet, what is mostly due to technical hurdles in matching biophysical properties to the complex demands of the CABG niche. But bacterial Nanocellulose (BNC) Hydrogels derived by growing biofilms hold a naturally integrative character in function-giving properties by its freedom in designing form and intrinsic fiber architecture. In this study we use this integral to combine impacts on the luminal fiber matrix, biomechanical properties and the reciprocal stimulation of microtopography and induced flow patterns, to investigate biomimetic and artificial designs on their bio-functional effects. Therefore, we produced tubular BNC-hydrogels at distinctive designs, characterized the structural and biomechanical properties and subjected them to in vitro endothelial colonization in bioreactor assisted perfusion cultivation. Results showed clearly improved functional properties and gave an indication of successfully realized stimulation by artery-typical helical flow patterns.
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- 2023
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3. Activation of the stress response among the cardiac surgical residents: comparison of teaching procedures and other (daily) medical activities
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George Awad, Robert Pohl, Sabine Darius, Beatrice Thielmann, Sam Varghese, Max Wacker, Hendrik Schmidt, Jens Wippermann, Maximilian Scherner, and Irina Böckelmann
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Cardiac surgery ,Education ,Workload ,Stress ,Heart rate variability ,Surgery ,RD1-811 ,Anesthesiology ,RD78.3-87.3 - Abstract
Abstract Background The aim of this Pilot study was to investigate the cardiac surgical residents’ workload during different surgical teaching interventions and to compare their stress levels with other working time spent in the intensive care unit or normal ward. Methods The objective stress was assessed using two cardiac surgical residents’ heart rate variability (HRV) both during surgical activities (32 selected teaching operations (coronary artery bypass graft n = 26 and transcatheter aortic valve implantation n = 6), and during non-surgical periods. Heart rate, time and frequency domains as well as non-linear parameters were analyzed using the Wilcoxon test. Results The parasympathetic activity was significantly reduced during the surgical phase, compared to the non-surgical phase: Mean RR (675.7 ms vs. 777.3 ms), RMSSD (23.1 ms vs. 34.0 ms) and pNN50 (4.7% vs. 10.6%). This indicates that the residents had a higher stress level during surgical activities in comparison to the non-surgical times. The evaluation of the Stress Index during the operations and outside the operating room (8.07 vs. 10.6) and the parasympathetic nervous system index (− 1.75 to − 0.91) as well as the sympathetic nervous system index (1.84 vs. 0.65) confirm the higher stress level during surgery. This can be seen too used the FFT Analysis with higher intraoperative LF/HF ratio (6.7 vs. 3.8). Conclusion HRV proved to be a good, objective method of identifying stress among physicians both in and outside the operating room. Our results show that residents are exposed to high psychological workloads during surgical activities, especially as the operating surgeon.
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- 2022
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4. Immunophenotyping of Monocyte Migration Markers and Therapeutic Effects of Selenium on IL-6 and IL-1β Cytokine Axes of Blood Mononuclear Cells in Preoperative and Postoperative Coronary Artery Disease Patients
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Max Wacker, Anna Ball, Hans-Dietmar Beer, Ingo Schmitz, Katrin Borucki, Faranak Azizzadeh, Maximilian Scherner, George Awad, Jens Wippermann, and Priya Veluswamy
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selenium ,post-cardiotomy syndrome ,coronary artery disease ,pro-inflammatory cytokines and monocytes ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Multivessel coronary artery disease (CAD) is characterized by underlying chronic vascular inflammation and occlusion in the coronary arteries, where these patients undergo coronary artery bypass grafting (CABG). Since post-cardiotomy inflammation is a well known phenomenon after CABG, attenuation of this inflammation is required to reduce perioperative morbidity and mortality. In this study, we aimed to phenotype circulating frequencies and intensities of monocyte subsets and monocyte migration markers, respectively, and to investigate the plasma level of inflammatory cytokines and chemokines between preoperative and postoperative CAD patients and later, to intervene the inflammation with sodium selenite. We found a higher amplitude of inflammation, postoperatively, in terms of CCR1high monocytes and significantly increased pro-inflammatory cytokines, IL-6, IL-8, and IL-1RA. Further, in vitro intervention with selenium displayed mitigating effects on the IL-6/STAT-3 axis of mononuclear cells derived from postoperative CAD patients. In addition, in vitro selenium intervention significantly reduced IL-1β production as well as decreased cleaved caspase-1 (p20) activity by preoperative (when stimulated) as well as postoperative CAD mononuclear cells. Though TNF-α exhibited a positive correlation with blood troponin levels in postoperative CAD patients, there was no obvious effect of selenium on the TNF-α/NF-κB axis. In conclusion, anti-inflammatory selenium might be utilized to impede systemic inflammatory cytokine axes to circumvent aggravating atherosclerosis and further damage to the autologous bypass grafts during the post-surgical period.
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- 2023
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5. Monitoring excimer laser-guided cardiac lead extractions by uniportal video-assisted thoracoscopy: A single center experience
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Sam Varghese, George Awad, Jens Wippermann, Ingo Slottosch, Henning Busk, Max Wacker, Patrick Zardo, Anke Lux, Lena Thewes, Maximilian Scherner, and Priya Veluswamy
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Pulmonary and Respiratory Medicine ,medicine.medical_specialty ,Pacemaker, Artificial ,Video-Assisted Surgery ,Single Center ,law.invention ,law ,medicine ,Thoracoscopy ,Operating time ,Humans ,Video assisted thoracoscopy ,Lead (electronics) ,Device Removal ,Retrospective Studies ,medicine.diagnostic_test ,business.industry ,General Medicine ,Intensive care unit ,Surgery ,Defibrillators, Implantable ,Electrodes, Implanted ,Treatment Outcome ,Concomitant ,Lasers, Excimer ,Cardiology and Cardiovascular Medicine ,business ,Lead extraction - Abstract
Background Though laser guided extractions of cardiac implantable electronic devices leads have become a routine procedure, the severe complications are associated with a high mortality. Here, we report our single center experience using uniportal video-assisted thoracoscopy for laser lead extraction and compare it to stand-alone laser lead extraction. Methods The intraoperative data and postoperative clinical outcomes of patients undergoing laser lead extraction with concomitant thoracoscopy ( N = 28) or without ( N = 43) in our institution were analyzed retrospectively. Results Neither the median x-ray time (612.0 s for the thoracoscopy group vs. 495.5 s for the non-thoracoscopy group, p = 0.962), length of the operation (112.5 vs. 100.0 min, p = 0.676) or the median length of hospital stay (9.0 vs. 10.0 days, p = 0.990) differed significantly. The mean intensive care unit stay was longer for patients in the non-thoracoscopy group (0.8 vs. 2.5 days, p = 0.005). The 30-day-mortality in the thoracoscopy group was zero, whereas five patients died in the non-thoracoscopy group. Furthermore, four patients in the non-thoracoscopy group had encountered haemothorax, while none were observed in the thoracoscopy group ( p = 0.148). Conclusions The adoption of uniportal video-assisted thoracoscopy during laser-guided lead extraction of cardiac implantable electronic devices can be considered safe and does not lengthen the operating time or hospital stay. It might be useful in the detection of severe complications and, in experienced hands, possibly allow direct bleeding control.
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- 2021
6. Bacterial Nanocellulose-Based Grafts for Cell Colonization Studies: An In Vitro Bioreactor Perfusion Model
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Max, Wacker, Jan, Riedel, Priya, Veluswamy, Maximilian, Scherner, Jens, Wippermann, Heike, Walles, and Jörn, Hülsmann
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Perfusion ,Bioreactors ,Tissue Engineering ,Endothelial Cells ,Blood Vessel Prosthesis - Abstract
With the aging population, the demand for artificial small diameter vascular grafts is constantly increasing, as the availability of autologous grafts is limited due to vascular diseases. A confluent lining with endothelial cells is considered to be a cornerstone for long-term patency of artificial small diameter grafts. We use bacterial nanocellulose off-the-shelf grafts and describe a detailed methodology to study the ability of these grafts to re-colonize with endothelial cells in an in vitro bioreactor model. The viability of the constructs generated in this process was investigated using established cell culture and tissue engineering methods, which includes WST-1 proliferation assay, AcLDL uptake assay, lactate balancing and histological characterization. The data generated this straight forward methodology allow an initial assessment of the principal prospects of success in forming a stable endothelium in artificial vascular prostheses.
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- 2021
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