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Voltage Mapping

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https://www.readbyqxmd.com/read/27902689/using-intrinsic-flavoprotein-and-nad-p-h-imaging-to-map-functional-circuitry-in-the-main-olfactory-bulb
#1
Cedric R Uytingco, Adam C Puche, Steven D Munger
Neurons exhibit strong coupling of electrochemical and metabolic activity. Increases in intrinsic fluorescence from either oxidized flavoproteins or reduced nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] in the mitochondria have been used as an indicator of neuronal activity for the functional mapping of neural circuits. However, this technique has not been used to investigate the flow of olfactory information within the circuitry of the main olfactory bulb (MOB). We found that intrinsic flavoprotein fluorescence signals induced by electrical stimulation of single glomeruli displayed biphasic responses within both the glomerular (GL) and external plexiform layers (EPL) of the MOB...
2016: PloS One
https://www.readbyqxmd.com/read/27875475/scar-based-catheter-ablation-for-persistent-atrial-fibrillation
#2
Pablo B Nery, Rebecca Thornhill, Girish M Nair, Elena Pena, Calum J Redpath
PURPOSE OF REVIEW: Percutaneous catheter ablation can be an effective treatment for paroxysmal atrial fibrillation. However, catheter ablation for the treatment of persistent atrial fibrillation or long-standing persistent atrial fibrillation is associated with success rates of 45-50% at 1 year. To address the challenge of ablating patients with persistent atrial fibrillation, several approaches have been proposed. Atrial scar-based catheter ablation is a promising strategy for ablation of persistent atrial fibrillation...
January 2017: Current Opinion in Cardiology
https://www.readbyqxmd.com/read/27862561/long-term-outcome-of-left-atrial-voltage-guided-substrate-ablation-during-atrial-fibrillation-a-novel-adjunctive-ablation-strategy
#3
Atsuhiko Yagishita, J Rod Gimbel, Samer DE Oliveira, Harish Manyam, Dina Sparano, Ivan Cakulev, Judith Mackall, Mauricio Arruda
INTRODUCTION: Left atrium (LA) low voltage area (LVA) on 3-D electroanatomic bipolar voltage mapping (EAVM), as a surrogate for scar, is associated with poor AF ablation outcome. We evaluated the long-term outcome of a LVA-guided atrial fibrillation (AF) substrate modification strategy as an adjunct to pulmonary vein isolation (PVI). METHODS AND RESULTS: Two hundred and one consecutive patients with AF (82% persistent / Non-PAF, age 65 years), who underwent EAVM during AF prior to PVI, were divided into two groups according to the presence or absence of LVA outside the PV antra, defined as bipolar voltage of < 0...
November 12, 2016: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/27861633/task-allocation-of-wasps-governed-by-common-stomach-a-model-based-on-electric-circuits
#4
Allison Hilbun, Istvan Karsai
Simple regulatory mechanisms based on the idea of the saturable 'common stomach' can control the regulation of construction behavior and colony-level responses to environmental perturbations in Metapolybia wasp societies. We mapped the different task groups to mutual inductance electrical circuits and used Kirchoff's basic voltage laws to build a model that uses master equations from physics, yet is able to provide strong predictions for this complex biological phenomenon. Similar to real colonies, independently of the initial conditions, the system shortly sets into an equilibrium, which provides optimal task allocation for a steady construction, depending on the influx of accessible water...
2016: PloS One
https://www.readbyqxmd.com/read/27853943/endocardial-voltage-mapping-of-pulmonary-veins-with-an-ultra-high-resolution-system-to-evaluate-atrial-myocardial-extensions
#5
Francesco Santoro, Christian Sohns, Ardan M Saguner, Natale Daniele Brunetti, Christine Lemes, Shibu Mathew, Christian-H Heeger, Bruno Reißmann, Tilman Maurer, Johannes Riedl, Thomas Fink, Kentaro Hayashi, Feifan Ouyang, Matteo Di Biase, Karl-Heinz Kuck, Andreas Metzner
INTRODUCTION: Atrial fibrillation (AF) is mainly triggered by arrhythmogenic foci originating from atrial myocardial extensions (MEs) into the pulmonary veins (PVs). Aim of the study was to evaluate endocardial voltage maps of PVs as a surrogate parameter for the extent of MEs in subjects with AF through a ultra-high-density mapping system. METHODS: Sixty-four bipolar electrograms were recorded simultaneously from the Orion mini-basket catheter placed in 72 PVs of 18 consecutive patients with paroxysmal/persistent AF undergoing PV isolation (PVI)...
November 16, 2016: Clinical Research in Cardiology: Official Journal of the German Cardiac Society
https://www.readbyqxmd.com/read/27853286/disulfide-mapping-the-voltage-sensing-mechanism-of-a-voltage-dependent-potassium-channel
#6
Tomohiro Nozaki, Shin-Ichiro Ozawa, Hitomi Harada, Tomomi Kimura, Masanori Osawa, Ichio Shimada
Voltage-dependent potassium (Kv) channels allow for the selective permeability of potassium ions in a membrane potential dependent manner, playing crucial roles in neurotransmission and muscle contraction. Kv channel is a tetramer, in which each subunit possesses a voltage-sensing domain (VSD) and a pore domain (PD). Although several lines of evidence indicated that membrane depolarization is sensed as the movement of helix S4 of the VSD, the detailed voltage-sensing mechanism remained elusive, due to the difficulty of structural analyses at resting potential...
November 17, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27837050/application-and-evaluation-of-independent-component-analysis-methods-to-generalized-seizure-disorder-activities-exhibited-in-the-brain
#7
S Thomas George, R Balakrishnan, J Stanly Johnson, J Jayakumar
EEG records the spontaneous electrical activity of the brain using multiple electrodes placed on the scalp, and it provides a wealth of information related to the functions of brain. Nevertheless, the signals from the electrodes cannot be directly applied to a diagnostic tool like brain mapping as they undergo a "mixing" process because of the volume conduction effect in the scalp. A pervasive problem in neuroscience is determining which regions of the brain are active, given voltage measurements at the scalp...
November 11, 2016: Clinical EEG and Neuroscience: Official Journal of the EEG and Clinical Neuroscience Society (ENCS)
https://www.readbyqxmd.com/read/27798186/genetically-targeted-all-optical-electrophysiology-with-a-transgenic-cre-dependent-optopatch-mouse
#8
Shan Lou, Yoav Adam, Eli N Weinstein, Erika Williams, Katherine Williams, Vicente Parot, Nikita Kavokine, Stephen Liberles, Linda Madisen, Hongkui Zeng, Adam E Cohen
: Recent advances in optogenetics have enabled simultaneous optical perturbation and optical readout of membrane potential in diverse cell types. Here, we develop and characterize a Cre-dependent transgenic Optopatch2 mouse line that we call Floxopatch. The animals expressed a blue-shifted channelrhodopsin, CheRiff, and a near infrared Archaerhodopsin-derived voltage indicator, QuasAr2, via targeted knock-in at the rosa26 locus. In Optopatch-expressing animals, we tested for overall health, genetically targeted expression, and function of the optogenetic components...
October 26, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27796454/strategy-for-non-target-ionic-analysis-by-capillary-electrophoresis-with-ultraviolet-detection
#9
Viktoria V Sursyakova, Galina V Burmakina, Anatoly I Rubaylo
A strategy for non-target analysis of samples with unknown composition by capillary electrophoresis (CE) with ultraviolet (UV) detection is suggested. The strategy is based on the preliminary identification of analytes and further optimization of the conditions for their separation using the developed computational tool set ElphoSeparation. It is shown that, in order to record electrophoretic peaks with the mobilities from the maximum to minimum possible values, the positive and negative voltage polarity and hydrodynamic pressure should be used...
October 28, 2016: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/27789203/radiation-optimized-dual-source-dual-energy-computed-tomography-pulmonary-angiography-intra-individual-and-inter-individual-comparison
#10
Xie Li, Guo Zhong Chen, Yan E Zhao, U Joseph Schoepf, Moritz H Albrecht, Matthew W Bickford, Hai Feng Gu, Long Jiang Zhang, Guang Ming Lu
OBJECTIVES: This study aimed to intra-individually and inter-individually compare image quality, radiation dose, and diagnostic accuracy of dual-source dual-energy computed tomography pulmonary angiography (CTPA) protocols in patients with suspected pulmonary embolism (PE). METHODS: Thirty-three patients with suspected PE underwent initial and follow-up dual-energy CTPA at 80/Sn140 kVp (group A) or 100/Sn140 kVp (group B), which were assigned based on tube voltages...
October 24, 2016: Academic Radiology
https://www.readbyqxmd.com/read/27788854/scar-homogenization-versus-limited-substrate-ablation-in-patients-with%C3%A2-nonischemic-cardiomyopathy-and%C3%A2-ventricular-tachycardia
#11
Yalçın Gökoğlan, Sanghamitra Mohanty, Carola Gianni, Pasquale Santangeli, Chintan Trivedi, Mahmut F Güneş, Rong Bai, Amin Al-Ahmad, G Joseph Gallinghouse, Rodney Horton, Patrick M Hranitzky, Javier E Sanchez, Salwa Beheiry, Richard Hongo, Dhanunjaya Lakkireddy, Madhu Reddy, Robert A Schweikert, Antonio Dello Russo, Michela Casella, Claudio Tondo, J David Burkhardt, Sakis Themistoclakis, Luigi Di Biase, Andrea Natale
BACKGROUND: Scar homogenization improves long-term ventricular arrhythmia-free survival compared with standard limited-substrate ablation in patients with post-infarction ventricular tachycardia (VT). Whether such benefit extends to patients with nonischemic cardiomyopathy and scar-related VT is unclear. OBJECTIVES: The aim of this study was to assess the long-term efficacy of an endoepicardial scar homogenization approach compared with standard ablation in this population...
November 1, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27786461/painting-with-rainbows-patterning-light-in-space-time-and-wavelength-for-multiphoton-optogenetic-sensing-and-control
#12
Daan Brinks, Yoav Adam, Simon Kheifets, Adam E Cohen
Photons are a fascinating reagent, flowing and reacting quite differently compared to more massive and less ephemeral particles of matter. The optogenetic palette comprises an ever growing set of light-responsive proteins, which open the possibility of using light to perturb and to measure biological processes with great precision in space and time. Yet there are limits on what light can achieve. Diffraction limits the smallest features, and scattering in tissue limits the largest. Photobleaching, diffusion of photogenerated products, and optical crosstalk between overlapping absorption spectra further muddy the optogenetic picture, particularly when one wants to use multiple optogenetic tools simultaneously...
October 27, 2016: Accounts of Chemical Research
https://www.readbyqxmd.com/read/27778005/a-scanning-tunneling-microscopy-study-of-the-electronic-and-spin-states-of-bis-phthalocyaninato-terbium-iii-tbpc2-molecules-on-ag-111
#13
Ferdous Ara, Zhi Kun Qi, Jie Hou, Tadahiro Komeda, Keiichi Katoh, Masahiro Yamashita
In this article, we investigate a single molecule magnet bis(phthalocyaninato)terbium(iii) (TbPc2) molecule film by using low temperature STM. In order to investigate the effect of molecule-substrate interaction on the electronic and spin properties of the adsorbed molecule, we tune the molecule-substrate coupling by switching the substrate between Au(111) and Ag(111), the latter of which provides stronger interaction with the molecule than the former. Despite the enhanced chemical reactivity of the Ag(111) surface compared with Au(111), a well-organized pseudo-square film is formed...
October 25, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27768696/fine-mapping-of-a-dravet-syndrome-modifier-locus-on-mouse-chromosome-5-and-candidate-gene-analysis-by-rna-seq
#14
Nicole A Hawkins, Nicole J Zachwieja, Alison R Miller, Lyndsey L Anderson, Jennifer A Kearney
A substantial number of mutations have been identified in voltage-gated sodium channel genes that result in various forms of human epilepsy. SCN1A mutations result in a spectrum of severity ranging from mild febrile seizures to Dravet syndrome, an infant-onset epileptic encephalopathy. Dravet syndrome patients experience multiple seizures types that are often refractory to treatment, developmental delays, and elevated risk for SUDEP. The same sodium channel mutation can produce epilepsy phenotypes of varying clinical severity...
October 2016: PLoS Genetics
https://www.readbyqxmd.com/read/27766868/photoadduct-formation-from-the-fmn-singlet-excited-state-in-the-lov2-domain-of-chlamydomonas-reinhardtii-phototropin
#15
Jingyi Zhu, Tilo Mathes, Yusaku Hontani, Maxime T A Alexandre, Kee Chua Toh, Peter Hegemann, John T M Kennis
The two Light, Oxygen, and Voltage domains of phototropin are blue-light photoreceptor domains which control various functions in plants and green algae. The key step of the light-driven reaction is the formation of a photoadduct between its FMN chromophore and a conserved cysteine, where the canonical reaction proceeds through the FMN triplet state. Here, complete photoreaction mapping of CrLOV2 from Chlamydomonas reinhardtii phototropin and AsLOV2 from Avena sativa phototropin-1 was realized by ultrafast broadband spectroscopy from femtoseconds to microseconds...
October 21, 2016: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/27764157/long-term-outcome-of-combined-percutaneous-intramyocardial-and-intracoronary-application-of-autologous-bone-marrow-mononuclear-cells-post-myocardial-infarction-the-5-year-mystar-study
#16
Mariann Gyöngyösi, Georgiana-Aura Giurgea, Bonni Syeda, Silvia Charwat, Beatrice Marzluf, Julia Mascherbauer, Andras Jakab, Abelina Zimba, Márta Sárközy, Noemi Pavo, Heinz Sochor, Senta Graf, Irene Lang, Gerald Maurer, Jutta Bergler-Klein
OBJECTIVE: The long-term (5-year) outcome of early (3-6 weeks after acute myocardial infarction [AMI], BM-MNC Early group) and late (3-4 months after AMI, BM-MNC Late group) combined (percutaneous intramyocardial and intracoronary) delivery of autologous bone marrow mononuclear cells (BM-MNCs) was evaluated in patients with ejection fractions (EF) between 30-45% post-AMI. METHODS: Major adverse cardiac and cerebrovascular events (MACCE) and hospitalization were recorded...
2016: PloS One
https://www.readbyqxmd.com/read/27762474/accuracy-of-voltage-signal-measurement-during-radiofrequency-delivery-through-the-smarttouch-catheter
#17
Payam Safavi-Naeini, Dreema Zafar-Awan, Hongjian Zhu, Gerardo Zablah, Anand V Ganapathy, Abdi Rasekh, Mohammad Saeed, Joanna Esther Molina Razavi, Mehdi Razavi
INTRODUCTION: Current methods for measuring voltage during radiofrequency (RF) ablation (RFA) necessitate turning off the ablation catheter. If voltage could be accurately read without signal attenuation during RFA, turning off the catheter would be unnecessary, allowing continuous ablation. We evaluated the accuracy of the Thermocool SMARTTOUCH catheter for measuring voltage while RF traverses the catheter. METHODS AND RESULTS: We studied 26 patients undergoing RFA for arrhythmias...
October 20, 2016: Journal of Cardiovascular Electrophysiology
https://www.readbyqxmd.com/read/27753494/direct-imaging-of-the-onset-of-electrical-conduction-in-silver-nanowire-networks-by-infra-red-thermography-evidence-of-geometrical-quantized-percolation
#18
Thomas Sannicolo, David Muñoz-Rojas, Ngoc Duy Nguyen, Stéphane Moreau, Caroline Celle, Jean-Pierre Simonato, Yves Bréchet, Daniel Bellet
Advancement in the science and technology of random metallic nanowire (MNW) networks is crucial for their appropriate integration in many applications, including transparent electrodes for optoelectronics and transparent film heaters. We have recently highlighted the discontinuous activation of efficient percolating pathways (EPPs) for networks having densities slightly above the percolation threshold. Such networks exhibit abrupt drops of electrical resistance when thermal or electrical annealing is performed, giving rise to a "geometrically quantized percolation"...
October 18, 2016: Nano Letters
https://www.readbyqxmd.com/read/27748433/optogenetics-design-of-mechanistically-based-stimulation-patterns-for-cardiac-defibrillation
#19
Claudia Crocini, Cecilia Ferrantini, Raffaele Coppini, Marina Scardigli, Ping Yan, Leslie M Loew, Godfrey Smith, Elisabetta Cerbai, Corrado Poggesi, Francesco S Pavone, Leonardo Sacconi
Current rescue therapies for life-threatening arrhythmias ignore the pathological electro-anatomical substrate and base their efficacy on a generalized electrical discharge. Here, we developed an all-optical platform to examine less invasive defibrillation strategies. An ultrafast wide-field macroscope was developed to optically map action potential propagation with a red-shifted voltage sensitive dye in whole mouse hearts. The macroscope was implemented with a random-access scanning head capable of drawing arbitrarily-chosen stimulation patterns with sub-millisecond temporal resolution allowing precise epicardial activation of Channelrhodopsin2 (ChR2)...
October 17, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27740904/electrocardiographic-impact-of-myocardial-diffuse-fibrosis-and-scar-mesa-multi-ethnic-study-of-atherosclerosis
#20
Yuko Y Inoue, Bharath Ambale-Venkatesh, Nathan Mewton, Gustavo J Volpe, Yoshiaki Ohyama, Ravi K Sharma, Colin O Wu, Chia-Ying Liu, David A Bluemke, Elsayed Z Soliman, João A C Lima, Hiroshi Ashikaga
Purpose To examine the associations of myocardial diffuse fibrosis and scar with surface electrocardiographic (ECG) parameters in individuals free of prior coronary heart disease in four different ethnicities. Materials and Methods This prospective cross-sectional study was approved by the institutional review boards, and all participants gave informed consent. A total of 1669 participants in the Multi-Ethnic Study of Atherosclerosis, or MESA, who were free of prior myocardial infarction underwent both ECG and cardiac magnetic resonance imaging...
October 13, 2016: Radiology
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