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Voltage Mapping

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https://www.readbyqxmd.com/read/29341322/isthmus-sites-identified-by-ripple-mapping-are-usually-anatomically-stable-a-novel-method-to-guide-atrial-substrate-ablation
#1
Vishal Luther, Norman Qureshi, Phang Boon Lim, Michael Koa-Wing, Shahnaz Jamil-Copley, Fu Siong Ng, Zachary Whinnett, D Wyn Davies, Nicholas S Peters, Prapa Kanagaratnam, Nick Linton
BACKGROUND: Post ablation reentrant ATs depend upon conducting isthmuses bordered by scar. Bipolar voltage maps highlight scar as sites of low voltage, but the voltage amplitude of an electrogram depends upon the myocardial activation sequence. Furthermore, a voltage threshold that defines atrial scar is unknown. We used Ripple Mapping (RM) to test whether these isthmuses were anatomically fixed between different activation vectors and atrial rates. METHODS: We studied post-AF ablation ATs where > 1 rhythm was mapped...
January 17, 2018: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/29338024/quantitative-in-vivo-mapping-of-myocardial-mitochondrial-membrane-potential
#2
Nathaniel M Alpert, Nicolas Guehl, Leon Ptaszek, Matthieu Pelletier-Galarneau, Jeremy Ruskin, Moussa C Mansour, Dustin Wooten, Chao Ma, Kazue Takahashi, Yun Zhou, Timothy M Shoup, Marc D Normandin, Georges El Fakhri
BACKGROUND: Mitochondrial membrane potential (ΔΨm) arises from normal function of the electron transport chain. Maintenance of ΔΨm within a narrow range is essential for mitochondrial function. Methods for in vivo measurement of ΔΨm do not exist. We use 18F-labeled tetraphenylphosphonium (18F-TPP+) to measure and map the total membrane potential, ΔΨT, as the sum of ΔΨm and cellular (ΔΨc) electrical potentials. METHODS: Eight pigs, five controls and three with a scar-like injury, were studied...
2018: PloS One
https://www.readbyqxmd.com/read/29335865/beneficial-effect-of-berberis-amurensis-rupr-on-penile-erection
#3
Rui Tan, Yun Jung Lee, Kyung Woo Cho, Dae Gill Kang, Ho Sub Lee
OBJECTIVE: To investigate whether the methanol extract of Berberis amurensis Rupr. (BAR) augments penile erection using in vitro and in vivo experiments. METHODS: The ex vivo study used corpus cavernosum strips prepared from adult male New Zealand White rabbits. In in vivo studies for intracavernous pressure (ICP), blood pressure, mean arterial pressure (MAP), and increase of peak ICP were continuously monitored during electrical stimulation of Sprague-Dawley rats...
January 15, 2018: Chinese Journal of Integrative Medicine
https://www.readbyqxmd.com/read/29335280/mapping-protein-interactions-of-sodium-channel-nav1-7-using-epitope-tagged-gene-targeted-mice
#4
Alexandros H Kanellopoulos, Jennifer Koenig, Honglei Huang, Martina Pyrski, Queensta Millet, Stéphane Lolignier, Toru Morohashi, Samuel J Gossage, Maude Jay, John E Linley, Georgios Baskozos, Benedikt M Kessler, James J Cox, Annette C Dolphin, Frank Zufall, John N Wood, Jing Zhao
The voltage-gated sodium channel NaV1.7 plays a critical role in pain pathways. We generated an epitope-tagged NaV1.7 mouse that showed normal pain behaviours to identify channel-interacting proteins. Analysis of NaV1.7 complexes affinity-purified under native conditions by mass spectrometry revealed 267 proteins associated with Nav1.7 in vivo The sodium channel β3 (Scn3b), rather than the β1 subunit, complexes with Nav1.7, and we demonstrate an interaction between collapsing-response mediator protein (Crmp2) and Nav1...
January 15, 2018: EMBO Journal
https://www.readbyqxmd.com/read/29328673/fluorescent-proteins-detect-host-structural-rearrangements-via-electrostatic-mechanism
#5
Lena Simine, Heiko Lammert, Li Sun, Jose Nelson Onuchic, Peter J Rossky
The rational design of genetically encoded fluorescent bio-sensors, which can detect rearrangements of target proteins via interdomain allostery, is hindered by the absence of mechanistic understanding of the underlying photo-physics. Here, we focus on the modulation of fluorescence by mechanical perturbation in a popular biological probe: enhanced Green Fluorescent Protein (eGFP). Using a combination of molecular dynamics (MD) simulations and quantum chemistry, and a set of physically motivated assumptions, we construct a map of fluorescence quantum yield as a function of a 2D electric field imposed by the protein environment on the fluorophore...
January 12, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29275886/the-extent-of-left-atrial-low-voltage-areas-included-in-pulmonary-vein-isolation-is-associated-with-freedom-from-recurrent-atrial-arrhythmia
#6
Dong Huang, Jing-Bo Li, Tarek Zghaib, Esra Gucuk Ipek, Muhammad Balouch, David D Spragg, Hiroshi Ashikaga, Harikrishna Tandri, Sunil K Sinha, Joseph E Marine, Ronald D Berger, Hugh Calkins, Saman Nazarian
BACKGROUND: The extent of left atrial (LA) baseline low-voltage areas (LVA-B), which may be a surrogate for fibrosis, is associated with recurrent atrial fibrillation (AF) after ablation. This study aimed to assess the relationship between the extent of LVA-B isolated by ablation (LVA-I) and AF recurrence. METHODS: The study cohort included 159 consecutive patients with drug-refractory AF who underwent an initial AF ablation with LA voltage mapping during sinus rhythm...
January 2018: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/29250289/mechanistic-insights-into-durable-pulmonary-vein-isolation-achieved-by-second-generation-cryoballoon-ablation
#7
Yasuo Okumura, Ichiro Watanabe, Kazuki Iso, Keiko Takahashi, Koichi Nagashima, Kazumasa Sonoda, Hiroaki Mano, Naoko Yamaguchi, Rikitake Kogawa, Ryuta Watanabe, Masaru Arai, Kimie Ohkubo, Sayaka Kurokawa, Toshiko Nakai, Atsushi Hirayama
Background: The mechanism explaining the efficacy of cryoballoon ablation (CBA) for atrial fibrillation has not been clarified. Methods and Results: We compared lesion characteristics between patients in whom pulmonary vein isolation (PVI) was performed by CBA (n=56) and those by contact force (CF)-based RF ablation (n=56). We evaluated the 3-dimensional PV morphology before and after cryoballoon inflation. After PVI, a 3D left atrial voltage map was created. Pacing (10 mA and 2 ms) was performed within the low voltage area from the ablation line, and electrically unexcitable ablated tissue was identified...
April 2017: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/29250270/high-voltage-guided-pulmonary-vein-isolation-in-paroxysmal-atrial-fibrillation
#8
Usama Boles, Enes E Gul, Andres Enriquez, Howard Lee, Dave Riegert, Adrian Andres, Adrian Baranchuk, Damian Redfearn, Benedict Glover, Chris Simpson, Hoshiar Abdollah, Kevin Michael
Background: Ablation of the pulmonary vein (PV) antrum using an electroanatomic mapping system is standard of care for point-by-point pulmonary vein isolation (PVI). Focused ablation at critical areas is more likely to achieve intra-procedural PV isolation and decrease the likelihood for reconnection and recurrence of atrial fibrillation (AF). Therefore this prospective pilot study is to investigate the short-term outcome of a voltage-guided circumferential PV ablation (CPVA) strategy...
February 2017: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/29250226/scar-homogenization-in-af-ablation-evolution-and-practice
#9
REVIEW
Minglong Chen
Laboratory studies, histology studies, image studies and the clinical studies all prove the positive correlation between atrial fibrillation and atrial fibrosis from different perspectives. Atrial fibrosis, by separating myocardial cell coupling, diminishing conduction velocity and promoting anisotropic conduction, produce the substrate to sustain atrial fibrillation (AF). These fibrotic areas can be translated into signal abnormalities (low voltage and complex electrgram), and be depicted by electroanatomic high density map...
June 2017: Journal of Atrial Fibrillation
https://www.readbyqxmd.com/read/29249605/high-resolution-cryoelectron-microscopy-structure-of-the-cyclic-nucleotide-modulated-potassium-channel-mlok1-in-a-lipid-bilayer
#10
Julia Kowal, Nikhil Biyani, Mohamed Chami, Sebastian Scherer, Andrzej J Rzepiela, Paul Baumgartner, Vikrant Upadhyay, Crina M Nimigean, Henning Stahlberg
Eukaryotic cyclic nucleotide-modulated channels perform their diverse physiological roles by opening and closing their pores to ions in response to cyclic nucleotide binding. We here present a structural model for the cyclic nucleotide-modulated potassium channel homolog from Mesorhizobium loti, MloK1, determined from 2D crystals in the presence of lipids. Even though crystals diffract electrons to only ∼10 Å, using cryoelectron microscopy (cryo-EM) and recently developed computational methods, we have determined a 3D map of full-length MloK1 in the presence of cyclic AMP (cAMP) at ∼4...
December 1, 2017: Structure
https://www.readbyqxmd.com/read/29225069/stimulation-of-b-raf-increases-c-jun-and-c-fos-expression-and-upregulates-ap-1-regulated-gene-transcription-in-insulinoma-cells
#11
Daniel S Langfermann, Oliver G Rössler, Gerald Thiel
Stimulation of pancreatic β-cells with glucose activates the protein kinases B-Raf and extracellular signal-regulated protein kinase that participate in glucose sensing. Inhibition of both kinases results in impairment of glucose-regulated gene transcription. To analyze the signaling pathway controlled by B-Raf, we expressed a conditionally active form of B-Raf in INS-1 insulinoma cells. Here, we show that stimulation of B-Raf strongly activated the transcription factor AP-1 which is accompanied by increased c-Jun and c-Fos promoter activities, an upregulation of c-Jun and c-Fos biosynthesis, and elevated transcriptional activation potentials of c-Jun and c-Fos...
December 7, 2017: Molecular and Cellular Endocrinology
https://www.readbyqxmd.com/read/29223305/usefulness-of-ultra-high-resolution-mapping-for-detecting-epicardial-atrial-activation-during-mitral-isthmus-ablation
#12
Hiroki Kitajima, Yuji Nishikawa, Keitaro Senoo, Masahiro Esato
We describe a patient with perimitral atrial flutter (PMF) following the atrial fibrillation ablation and the linear ablation at the mitral isthmus (MI). From both the activation and the voltage maps using ultra-high resolution mapping, we detected the epicardial connection through the coronary sinus (CS) within the entire reentrant circuit. Point ablation within the CS, not additional linear MI ablation from the endocardium terminates PMF, with a bidirectional block across the low voltage area at the MI.
November 21, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29218991/multimodal-kelvin-probe-force-microscopy-investigations-of-a-photovoltaic-wse2-mos2-type-ii-interface
#13
Yann Almadori, Nedjma Bendiab, Benjamin Grevin
Atomically thin transition metal dichalcogenides (TMDC) have become a new platform for the development of next-generation opto-electronic and light harvesting devices. Here, we report a Kelvin probe force microscopy (KPFM) investigation carried out on a type-II photovoltaic heterojunction based on WSe2 monolayer flakes and a bilayer MoS2 film stacked in vertical configuration on a Si/SiO2 substrate. Band offset characterized by a significant interfacial dipole is pointed out at the WSe2/MoS2 vertical junction...
December 8, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29215058/hybrid-black-silicon-solar-cells-textured-with-the-interplay-of-copper-induced-galvanic-displacement
#14
Jheng-Yi Li, Chia-Hsiang Hung, Chia-Yun Chen
Metal-assisted chemical etching (MaCE) has been widely employed for the fabrication of regular silicon (Si) nanowire arrays. These features were originated from the directional etching of Si preferentially along <100> orientations through the catalytic assistance of metals, which could be gold, silver, platinum or palladium. In this study, the dramatic modulation of etching profiles toward pyramidal architectures was undertaken by utilizing copper as catalysts through a facile one-step etching process, which paved the exceptional way on the texturization of Si for advanced photovoltaic applications...
December 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29203667/electrostatic-confinement-and-manipulation-of-dna-molecules-for-genome-analysis
#15
Kristy L Kounovsky-Shafer, Juan P Hernandez-Ortiz, Konstantinos Potamousis, Gene Tsvid, Michael Place, Prabu Ravindran, Kyubong Jo, Shiguo Zhou, Theo Odijk, Juan J de Pablo, David C Schwartz
Very large DNA molecules enable comprehensive analysis of complex genomes, such as human, cancer, and plants because they span across sequence repeats and complex somatic events. When physically manipulated, or analyzed as single molecules, long polyelectrolytes are problematic because of mechanical considerations that include shear-mediated breakage, dealing with the massive size of these coils, or the length of stretched DNAs using common experimental techniques and fluidic devices. Accordingly, we harness analyte "issues" as exploitable advantages by our invention and characterization of the "molecular gate," which controls and synchronizes formation of stretched DNA molecules as DNA dumbbells within nanoslit geometries...
December 4, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29197656/endocardial-infarct-scar-recognition-by-myocardial-electrical-impedance-is-not-influenced-by-changes-in-cardiac-activation-sequence
#16
Gerard Amorós-Figueras, Esther Jorge, Concepción Alonso-Martin, Daniel Traver, Maria Ballesta, Ramon Bragós, Javier Rosell-Ferrer, Juan Cinca
BACKGROUND: Measurement of myocardial electrical impedance can allow recognition of infarct scar and theoretically is not influenced by changes in cardiac activation sequence, but this is not known. OBJECTIVES: To evaluate the ability of endocardial electrical impedance measurements to recognize areas of infarct scar and to assess the stability of the impedance data under changes of cardiac activation sequence. METHODS: One month-old myocardial infarction confirmed by cardiac magnetic resonance (CMR) was induced in five pigs submitted to coronary artery catheter-balloon occlusion...
November 29, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29187667/strategy-and-outcome-of-catheter-ablation-for-persistent-atrial-fibrillation%C3%A3-impact-of-progress-in-the-mapping-and-ablation-technologies
#17
Hideharu Okamatsu, Ken Okumura
Pulmonary vein (PV) antrum isolation (PVAI) is effective in treating paroxysmal atrial fibrillation (AF) but is less so for persistent AF. A recent randomized study on the ablation strategies for persistent AF demonstrated that 2 common atrial substrate modifications, creation of linear lesions in the left atrium and ablation of complex fractionated electrogram sites, in addition to PVAI did not improve the outcome compared with stand-alone PVAI, suggesting the necessity of a more individualized, selective approach to persistent AF...
November 30, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/29177475/individually-tailored-vs-standardized-substrate-modification-during-radiofrequency-catheter-ablation-for-atrial-fibrillation-a-randomized-study
#18
Simon Kircher, Arash Arya, David Altmann, Sascha Rolf, Andreas Bollmann, Philipp Sommer, Nikolaos Dagres, Sergio Richter, Ole-A Breithardt, Borislav Dinov, Daniela Husser, Charlotte Eitel, Thomas Gaspar, Christopher Piorkowski, Gerhard Hindricks
Aims: This randomized single-centre study sought to compare the efficacy and safety of pulmonary vein isolation (PVI) plus voltage-guided ablation vs. PVI with or without linear ablation depending on the type of atrial fibrillation (AF). Methods and results: Overall, 124 ablation-naive patients with paroxysmal or persistent AF were randomized to PVI with (persistent AF) or without (paroxysmal AF) additional linear ablation (control group) vs. PVI plus ablation of low-voltage areas (LVAs) irrespective of AF type...
November 21, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29165835/the-function-of-contactin-2-tag-1-in-oligodendrocytes-in-health-and-demyelinating-pathology
#19
Lida Zoupi, Maria Savvaki, Katerina Kalemaki, Ilias Kalafatakis, Kyriaki Sidiropoulou, Domna Karagogeos
The oligodendrocyte maturation process and the transition from the pre-myelinating to the myelinating state are extremely important during development and in pathology. In the present study, we have investigated the role of the cell adhesion molecule CNTN2/TAG-1 on oligodendrocyte proliferation, differentiation, myelination, and function during development and under pathological conditions. With the combination of in vivo, in vitro, ultrastructural, and electrophysiological methods, we have mapped the expression of CNTN2 protein in the oligodendrocyte lineage during the different stages of myelination and its involvement on oligodendrocyte maturation, branching, myelin-gene expression, myelination, and axonal function...
November 22, 2017: Glia
https://www.readbyqxmd.com/read/29164019/quantitative-analysis-of-electro-anatomical-maps-application-to-an-experimental-model-of-left-bundle-branch-block-cardiac-resynchronization-therapy
#20
David Soto Iglesias, Nicolas Duchateau, Constantine Butakoff Kostantyn Butakov, David Andreu, Juan Fernandez-Armenta, Bart Bijnens, Antonio Berruezo, Marta Sitges, Oscar Camara
Electro-anatomical maps (EAMs) are commonly acquired in clinical routine for guiding ablation therapies. They provide voltage and activation time information on a 3-D anatomical mesh representation, making them useful for analyzing the electrical activation patterns in specific pathologies. However, the variability between the different acquisitions and anatomies hampers the comparison between different maps. This paper presents two contributions for the analysis of electrical patterns in EAM data from biventricular surfaces of cardiac chambers...
2017: IEEE Journal of Translational Engineering in Health and Medicine
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