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Find video protocols related to scientific articles indexed in Pubmed.
Mitochondrial depolarization and electrophysiological changes during ischemia in the rabbit and human heart.
Am. J. Physiol. Heart Circ. Physiol.
PUBLISHED: 08-15-2014
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Instability of the inner mitochondrial membrane potential (??m) has been implicated in electrical dysfunction, including arrhythmogenesis during ischemia-reperfusion. Monitoring ??m has led to conflicting results, where depolarization has been reported as sporadic and as a propagating wave. The present study was designed to resolve the aforementioned difference and determine the unknown relationship between ??m and electrophysiology. We developed a novel imaging modality for simultaneous optical mapping of ??m and transmembrane potential (Vm). Optical mapping was performed using potentiometric dyes on preparations from 4 mouse hearts, 14 rabbit hearts, and 7 human hearts. Our data showed that during ischemia, ??m depolarization is sporadic and changes asynchronously with electrophysiological changes. Spatially, ??m depolarization was associated with action potential duration shortening but not conduction slowing. Analysis of focal activity indicated that ??m is not different within the myocardium where the focus originates compared with normal ventricular tissue. Overall, our data suggest that during ischemia, mitochondria maintain their function at the expense of sarcolemmal electrophysiology, but ??m depolarization does not have a direct association to ischemia-induced arrhythmias.
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Patient-specific flexible and stretchable devices for cardiac diagnostics and therapy.
Prog. Biophys. Mol. Biol.
PUBLISHED: 08-05-2014
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Advances in material science techniques and pioneering circuit designs have led to the development of electronic membranes that can form intimate contacts with biological tissues. In this review, we present the range of geometries, sensors, and actuators available for custom configurations of electronic membranes in cardiac applications. Additionally, we highlight the desirable mechanics achieved by such devices that allow the circuits and substrates to deform with the beating heart. These devices unlock opportunities to collect continuous data on the electrical, metabolic, and mechanical state of the heart as well as a platform on which to develop high definition therapeutics.
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A shocking past: a walk through generations of defibrillation development.
IEEE Trans Biomed Eng
PUBLISHED: 04-25-2014
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Defibrillation is one of the most successful and widely recognized applications of electrotherapy. Yet the historical road to its first successful application in a patient and the innovative adaptation to an implantable device is marred with unexpected turns, political and personal setbacks, and public and scientific condemnation at each new idea. Driven by dedicated scientists and ever-advancing creative applications of new technologies, from electrocardiography to high density mapping and computational simulations, the field of defibrillation persevered and continued to evolve to the life-saving tool it is today. In addition to critical technological advances, the history of defibrillation is also marked by the plasticity of the theory of defibrillation. The advancing theories of success have propelled the campaign for reducing the defibrillation energy requirement, instilling hope in the development of a painless and harmless electrical defibrillation strategy.
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3D multifunctional integumentary membranes for spatiotemporal cardiac measurements and stimulation across the entire epicardium.
Nat Commun
PUBLISHED: 01-27-2014
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Means for high-density multiparametric physiological mapping and stimulation are critically important in both basic and clinical cardiology. Current conformal electronic systems are essentially 2D sheets, which cannot cover the full epicardial surface or maintain reliable contact for chronic use without sutures or adhesives. Here we create 3D elastic membranes shaped precisely to match the epicardium of the heart via the use of 3D printing, as a platform for deformable arrays of multifunctional sensors, electronic and optoelectronic components. Such integumentary devices completely envelop the heart, in a form-fitting manner, and possess inherent elasticity, providing a mechanically stable biotic/abiotic interface during normal cardiac cycles. Component examples range from actuators for electrical, thermal and optical stimulation, to sensors for pH, temperature and mechanical strain. The semiconductor materials include silicon, gallium arsenide and gallium nitride, co-integrated with metals, metal oxides and polymers, to provide these and other operational capabilities. Ex vivo physiological experiments demonstrate various functions and methodological possibilities for cardiac research and therapy.
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Three-dimensional printing physiology laboratory technology.
Am. J. Physiol. Heart Circ. Physiol.
PUBLISHED: 09-16-2013
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Since its inception in 19th-century Germany, the physiology laboratory has been a complex and expensive research enterprise involving experts in various fields of science and engineering. Physiology research has been critically dependent on cutting-edge technological support of mechanical, electrical, optical, and more recently computer engineers. Evolution of modern experimental equipment is constrained by lack of direct communication between the physiological community and industry producing this equipment. Fortunately, recent advances in open source technologies, including three-dimensional printing, open source hardware and software, present an exciting opportunity to bring the design and development of research instrumentation to the end user, i.e., life scientists. Here we provide an overview on how to develop customized, cost-effective experimental equipment for physiology laboratories.
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Multi-Stage Electrotherapy Delivered Through Chronically Implanted Leads Terminates Atrial Fibrillation with Lower Energy than a Single Biphasic Shock.
J. Am. Coll. Cardiol.
PUBLISHED: 03-22-2013
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The authors sought to develop a low-energy, implantable device-based multi-stage electrotherapy (MSE) to terminate atrial fibrillation (AF).
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S-nitrosation of arginase 1 requires direct interaction with inducible nitric oxide synthase.
Mol. Cell. Biochem.
PUBLISHED: 04-19-2011
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Arginase constrains endothelial nitric oxide synthase activity by competing for the common substrate, L -Arginine. We have recently shown that inducible nitric oxide synthase (NOS2) S-nitrosates and activates arginase 1 (Arg1) leading to age-associated vascular dysfunction. Here, we demonstrate that a direct interaction of Arg1 with NOS2 is necessary for its S-nitrosation. The specific domain of NOS2 that mediates this interaction is identified. Disruption of this interaction in human aortic endothelial cells prevents Arg1 S-nitrosation and activation. Thus, disruption of NOS2-Arg1 interaction may represent a therapeutic strategy to attenuate age related vascular endothelial dysfunction.
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Impact of platelet transfusion on hematoma expansion in patients receiving antiplatelet agents before intracerebral hemorrhage.
Neurol. Res.
PUBLISHED: 09-08-2010
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Patients receiving antiplatelet medications are reported to be at increased risk for hematoma enlargement and worse clinical outcomes following intracerebral hemorrhage (ICH). While platelet transfusions are frequently administered to counteract qualitative platelet defects in the setting of ICH, conclusive evidence in support of this therapeutic strategy is lacking. In fact, platelet transfusions may be associated with adverse effects, and represent a finite resource. We sought to determine the clinical efficacy of platelet transfusion and its impact on systemic complications following ICH in a cohort of patients receiving antiplatelet medications.
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Decreased S-nitrosylation of tissue transglutaminase contributes to age-related increases in vascular stiffness.
Circ. Res.
PUBLISHED: 05-20-2010
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Although an age-related decrease in NO bioavailability contributes to vascular stiffness, the underlying molecular mechanisms remain incompletely understood. We hypothesize that NO constrains the activity of the matrix crosslinking enzyme tissue transglutaminase (TG2) via S-nitrosylation in young vessels, a process that is reversed in aging.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.