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In JoVE (2)
- Optical Mapping of Langendorff-perfused Rat Hearts
- Implantation of Engineered Tissue in the Rat Heart
Other Publications (7)
- Clinical Science (London, England : 1979)
- Journal of Investigative Medicine : the Official Publication of the American Federation for Clinical Research
- Journal of Cardiac Surgery
- The Journal of Surgical Research
- The Journal of Heart Valve Disease
- The Annals of Thoracic Surgery
- The Annals of Thoracic Surgery
Articles by Bjoern Sill in JoVE
Optical Mapping of Langendorff-perfused Rat Hearts
Bjoern Sill1, Peter E. Hammer1,2, Douglas B. Cowan1
1Department of Anesthesiology, Perioperative and Pain Medicine, Children's Hospital Boston and Harvard Medical School, 2Departments of Cardiac Surgery, Children's Hospital Boston and Harvard Medical School
This article describes a high temporal and spatial resolution technique to optically image action potential movement on the surface of Langendorff-perfused rat hearts using a potentiometric dye (di-8-ANEPPS).
Implantation of Engineered Tissue in the Rat Heart
Bjoern Sill1, Ivan V. Alpatov2, Christina A. Pacak2, Douglas B. Cowan2
1Department of Anesthesiology, Perioperative and Pain Medicine, Children's Hospital Boston and Harvard Medical School, 2Department of Anesthesiology, Perioperative and Pain Medicine, Children’s Hospital Boston
Here, we describe a cardiac surgical procedure to implant engineered tissue in the atrioventricular (AV)-groove of an adult Lewis rat.
Other articles by Bjoern Sill on PubMed
Clinical Science (London, England : 1979). Aug, 2002 | Pubmed ID: 12193080
A dysregulated metabolism of oxygen-derived free radicals, nitric oxide and endothelin-1(ET-1) in conditions such as hypercholesterolaemia or hypertension may promote the development of atherosclerosis. We therefore subjected cultured human umbilical vein endothelial cells and coronary artery smooth muscle cells to oxidative stress induced by xanthine oxidase or hydrogen peroxide and observed alterations in ET-1 metabolism. Incubation with oxygen-derived free radicals increased preproET-1 promoter activity, ET-1 mRNA synthesis and big ET-1 concentrations in both cell types. This interaction of oxidative stress and ET-1 expression may be relevant in atherogenic conditions such as hypercholesterolaemia and hypertension since our data indicate that oxidative stress further aggravates the injurious effects attributed to ET-1.
Journal of Investigative Medicine : the Official Publication of the American Federation for Clinical Research. Sep, 2007 | Pubmed ID: 17963680
Endothelin-1, angiotensin II, and oxygen-derived radicals are pivotal factors in the development and progression of atherosclerosis. In vitro studies suggest that generation of oxygen-derived radicals by angiotensin II is an important mechanism increasing endothelin-1 synthesis, which consecutively may trigger effects such as cell proliferation and hypertrophy. The aim of this study was to confirm our previous data in an ex vivo and an in vivo setting. Explanted segments of internal mammary arteries were analyzed for big endothelin-1 expression following incubation with xanthine oxidase, angiotensin II, superoxide dismutase, and catalase to stimulate or to specifically inactivate oxygen-derived radicals. Endothelin-1 concentrations were determined by immunostaining and enzyme-linked immunosorbent assay. Further, oxypurinol was given to patients undergoing coronary angioplasty, a procedure known to increase plasma endothelin-1 concentrations. Angiotensin II and xanthine oxidase dose-dependently increased big endothelin-1 concentrations (p < .01 and p < .0001); the effects could be inhibited by coincubation with superoxide dismutase and catalase as determined by both semiquantitative immunofluorescence and enzyme-linked immunosorbent assay (p < .01). Patients undergoing coronary angioplasty exhibited significantly elevated big endothelin-1 concentrations 60 minutes after angioplasty (p = .03); in patients also receiving oxypurinol immediately after angioplasty, big endothelin-1 concentrations decreased (p = .001). Our results may explain the association between elevated angiotensin II levels, increased oxidative stress, and increased endothelin-1 concentrations in atherosclerosis. The data therefore support the concept that oxygen-derived free radicals stimulate the release of endothelin-1, which subsequently induces effects such as proliferation and enhanced agonist-induced vasoconstriction, previously attributed directly to angiotensin II.
Journal of Cardiac Surgery. Nov, 2010 | Pubmed ID: 21044157
We evaluated the long-term outcome of aortic valve after arterial switch operation (ASO).
The Journal of Surgical Research. Apr, 2011 | Pubmed ID: 21227467
Complete heart block is a significant clinical problem that can limit the quality of life in affected children. To understand the pathophysiology of this condition and provide for development of novel therapies, we sought to establish a large animal model of permanent, pacemaker-dependent atrioventricular block (AVB) that mimics the size and growth characteristics of pediatric patients.
Creation of a Tricuspid Valve Regurgitation Model from Tricuspid Annular Dilatation Using the Cardioport Video-assisted Imaging System
The Journal of Heart Valve Disease. Mar, 2011 | Pubmed ID: 21560820
Experimental models of tricuspid valve regurgitation (TR) are used to study novel annuloplasty techniques (including prosthetic rings), and they can also serve as physiologic models to investigate TR pathophysiology. The study aim was to develop an appropriate simple and reproducible experimental model of TR from annular dilatation.
The Annals of Thoracic Surgery. Aug, 2011 | Pubmed ID: 21801900
Among patients with end-stage lung disease awaiting lung transplantation, pediatric and small adult patients have a significantly lower chance of getting size-matched pulmonary grafts in time because of the severe scarcity of small donors. It is our strategy to perform lobar lung transplantations in small recipients with restrictive pulmonary disease once their clinical status demands urgent transplantation. Here we describe our surgical technique and discuss the benefits and risks of this procedure.
Transcatheter Valve-in-Valve Implantation for Deteriorated Aortic Bioprosthesis: Initial Clinical Results and Follow-Up in a Series of High-Risk Patients
The Annals of Thoracic Surgery. Feb, 2012 | Pubmed ID: 22304904
BACKGROUND: Transcatheter aortic valve implantation (TAVI) has become a viable alternative in maximum risk patients. For those patients requiring aortic valve re-replacement, the "valve-in-valve" concept has been described. We report our experience with transapical valve-in-valve implantation in 7 patients with deteriorated aortic bioprosthesis at 1-year follow up. METHODS: Since November 2008, 210 patients received transapical TAVI due to severe aortic stenosis. Seven patients presented with deteriorated aortic valve bioprosthesis and received transapical valve-in-valve implantation. Mean age was 78.7 ± 0.8 years. Preoperatively, all patients were at New York Heart Association (NYHA) functional class III. For risk estimation, the Society of Thoracic Surgeons (STS) and European System for Cardiac Operative Risk Evaluation (ES) risk scores were used and predicted high mortality (means ± standard error of the mean: STS(Mortality)21.6 ± 2.8%, ES(add)14.9 ± 1.1, ES(log) 52.6 ± 9.0%). Mean follow-up time was 517 ± 65 days (range, 280 to 799 days). RESULTS: Six patients showed a severely deteriorated bioprosthesis in terms of a stenotic valve (aortic valve area: 0.64 ± 0.04 cm(2), maximum/mean developed transvalvular pressure gradient: dPmax 63.3 ± 10.9mmHg, dPmean 40.4 ± 5.6 mm Hg). One patient's deteriorated prosthesis was highly insufficient. Procedural success rate was 100%, mean procedure time was 46.7 ± 12.3 minutes. Echocardiography revealed excellent hemodynamics of implanted prosthesis (dPmax 31.1 ± 5.5 mm Hg; dPmean 19.4 ± 4.3 mm Hg). Overall, postoperative course was uneventful. No patient died during follow-up, which ranged up to 26 months. All patients, except 1, remained in NYHA class I or II. CONCLUSIONS: Our results demonstrate feasibility and safety of the transapical valve-in-valve approach with excellent hemodynamic and clinical results. Decision making in a multidisciplinary setting is mandatory. Further studies with more patients and longer follow-up are needed to identify candidates benefiting from transapical transcatheter valve-in-valve implantation.