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https://www.readbyqxmd.com/read/29778719/effect-of-heptanol-and-ethanol-on-excitation-wave-propagation-in-a-neonatal-rat-ventricular-myocyte-monolayer
#1
A D Podgurskaya, V A Tsvelaya, S R Frolova, I Y Kalita, N N Kudryashova, K I Agladze
In this work, the action of heptanol and ethanol was investigated in a two-dimensional (2D) model of cardiac tissue: the neonatal rat ventricular myocyte monolayer. Heptanol is known in electrophysiology as a gap junction uncoupler but may also inhibit voltage-gated ionic channels. Ethanol is often associated with the occurrence of arrhythmias. These substances influence sodium, calcium, and potassium channels, but the complete mechanism of action of heptanol and ethanol remains unknown. The optical mapping method was used to measure conduction velocities (CVs) in concentrations of 0...
May 17, 2018: Toxicology in Vitro: An International Journal Published in Association with BIBRA
https://www.readbyqxmd.com/read/29769525/asynchronous-suppression-of-visual-cortex-during-absence-seizures-in-stargazer-mice
#2
Jochen Meyer, Atul Maheshwari, Jeffrey Noebels, Stelios Smirnakis
Absence epilepsy is a common childhood disorder featuring frequent cortical spike-wave seizures with a loss of awareness and behavior. Using the calcium indicator GCaMP6 with in vivo 2-photon cellular microscopy and simultaneous electrocorticography, we examined the collective activity profiles of individual neurons and surrounding neuropil across all layers in V1 during spike-wave seizure activity over prolonged periods in stargazer mice. We show that most (~80%) neurons in all cortical layers reduce their activity during seizures, whereas a smaller pool activates or remains neutral...
May 16, 2018: Nature Communications
https://www.readbyqxmd.com/read/29745425/arrhythmic-hazard-map-for-a-3d-whole-ventricles-model-under-multiple-ion-channel-block
#3
Jun-Ichi Okada, Takashi Yoshinaga, Junko Kurokawa, Takumi Washio, Tetsushi Furukawa, Kohei Sawada, Seiryo Sugiura, Toshiaki Hisada
BACKGROUND AND PURPOSE: To date, proposed in silico models for preclinical cardiac safety testing are limited in their predictability and usability. We previously reported a multi-scale heart simulation that accurately predicts arrhythmogenic risk for benchmark drugs. EXPERIMENTAL APPROACH: We extend this approach and report the first comprehensive hazard map of drug-induced arrhythmia based on the exhaustive in silico electrocardiogram (ECG) database of drug effects, developed using a petaflop computer...
May 10, 2018: British Journal of Pharmacology
https://www.readbyqxmd.com/read/29739509/ultrasonic-assisted-conversion-of-limestone-into-needle-like-hydroxyapatite-nanoparticles
#4
Jutharatana Klinkaewnarong, Songkot Utara
Needle-like hydroxyapatite nanoparticles were successfully synthesized via a reaction between calcium oxide (CaO) that was obtained from calcined limestone and orthophosphoric acid (H3 PO4 ) under ultrasonic irradiation at 25 °C. The reaction systems were exposed to ultrasonic waves of 20 kHz for various times ranging from 0 to 4 h. The initial and final pH values of the mixtures of CaO and H3 PO4 solution were continuously observed (pH < 4.0) after ultrasonic irradiation. The powder was then dried at 60 °C and calcined at 300 °C for 3 h (3 °C/min)...
September 2018: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/29686143/elevation-of-cytosolic-ca-2-in-response-to-energy-deficiency-in-plants-the-general-mechanism-of-adaptation-to-low-oxygen-stress
#5
REVIEW
Abir U Igamberdiev, Robert D Hill
Ca2+ can be released from cell compartments to the cytosol during stress conditions. We discuss here the causes of Ca2+ release under conditions of ATP concentration decline that result in the suppression of ATPases and activation of calcium ion channels. The main signaling and metabolic consequences of Ca2+ release are considered for stressed plant cells. The signaling function includes generation and spreading of calcium waves, while the metabolic function results in the activation of particular enzymes and genes...
April 23, 2018: Biochemical Journal
https://www.readbyqxmd.com/read/29686107/descending-pathway-facilitates-undulatory-wave-propagation-in-caenorhabditis-elegans-through-gap-junctions
#6
Tianqi Xu, Jing Huo, Shuai Shao, Michelle Po, Taizo Kawano, Yangning Lu, Min Wu, Mei Zhen, Quan Wen
Descending signals from the brain play critical roles in controlling and modulating locomotion kinematics. In the Caenorhabditis elegans nervous system, descending AVB premotor interneurons exclusively form gap junctions with the B-type motor neurons that execute forward locomotion. We combined genetic analysis, optogenetic manipulation, calcium imaging, and computational modeling to elucidate the function of AVB-B gap junctions during forward locomotion. First, we found that some B-type motor neurons generate rhythmic activity, constituting distributed oscillators...
April 23, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29682539/effect-of-kisspeptin-on-the-developmental-competence-and-early-transcript-expression-in-porcine-oocytes-parthenogenetically-activated-with-different-methods
#7
Islam M Saadeldin, Ayman Abdel-Aziz Swelum, Aaser M Abdelazim, Essam A Almadaly
Recent studies showed the modulatory effect of kisspeptin (KP) on calcium waves through the cell membrane and inside the cell. Spermatozoon can induce similar ooplasmic calcium oscillations at fertilization to trigger meiosis II. Here, we evaluated the effect of KP supplementation with 6-dimethylaminopurine (6-DMAP) for 4 h on embryonic development after oocyte activation with single electric pulse, 5 µ M ionomycin, or 8% ethanol. Compared to control nonsupplemented groups, KP significantly improved embryo developmental competence electric- and ethanol-activated oocytes in terms of cleavage (75...
2018: BioMed Research International
https://www.readbyqxmd.com/read/29674971/a-numerical-study-of-scalable-cardiac-electro-mechanical-solvers-on-hpc-architectures
#8
Piero Colli Franzone, Luca F Pavarino, Simone Scacchi
We introduce and study some scalable domain decomposition preconditioners for cardiac electro-mechanical 3D simulations on parallel HPC (High Performance Computing) architectures. The electro-mechanical model of the cardiac tissue is composed of four coupled sub-models: (1) the static finite elasticity equations for the transversely isotropic deformation of the cardiac tissue; (2) the active tension model describing the dynamics of the intracellular calcium, cross-bridge binding and myofilament tension; (3) the anisotropic Bidomain model describing the evolution of the intra- and extra-cellular potentials in the deforming cardiac tissue; and (4) the ionic membrane model describing the dynamics of ionic currents, gating variables, ionic concentrations and stretch-activated channels...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29668881/hyperactive-ryanodine-receptors-in-human-heart-failure-and-ischemic-cardiomyopathy-reside-outside-of-couplons
#9
Eef Dries, Demetrio J Santiago, Guillaume Gilbert, Ilse Lenaerts, Bert Vandenberk, Chandan K Nagaraju, Daniel M Johnson, Patricia Holemans, H Llewelyn Roderick, Niall Macquaide, Piet Claus, Karin R Sipido
Aims: In ventricular myocytes from humans and large mammals, the transverse and axial tubular system (TATS) network is less extensive than in rodents with consequently a greater proportion of ryanodine receptors (RyRs) not coupled to this membrane system. TATS remodeling in heart failure (HF) and after myocardial infarction (MI) increases the fraction of non-coupled RyR. Here we investigate whether this remodeling alters the activity of coupled and non-coupled RyR sub-populations through changes in local signaling...
April 14, 2018: Cardiovascular Research
https://www.readbyqxmd.com/read/29663283/eeg-artifact-versus-subclinical-status-epilepticus-in-a-patient-following-cardiac-arrest
#10
Jean E Cibula, Daniel S Demos, Brenda G Fahy
BACKGROUND: A challenge in ICU EEG interpretation is identifying subclinical status epilepticus versus patterns on the ictal-interictal continuum versus other repetitive patterns. In the electrically noisy intensive care unit, identifying and eliminating interference and artifact allow accurate diagnoses from the EEG, avoiding unnecessary treatment or sedation. METHODS: We present a case during Impella (Abiomed Inc, Danvers, MA) continuous flow left ventricular assist device use where the EEG artifact was initially misinterpreted as seizure by the resident and treated as status epilepticus because of the "focal" sharply contoured repetitive pattern...
April 16, 2018: Neurocritical Care
https://www.readbyqxmd.com/read/29626474/canstatin-modulates-l-type-calcium-channel-activity-in-rat-ventricular-cardiomyocytes
#11
Keisuke Imoto, Masaki Hirakawa, Muneyoshi Okada, Hideyuki Yamawaki
Excessive increase of cytosolic Ca2+ through the activation of L-type Ca2+ channels (LTCCs) via β adrenergic receptor induces apoptosis of cardiomyocytes. Canstatin, a cleaved fragment of collagen type IV α2 chain, is abundantly expressed in normal heart tissue. We previously reported that canstatin inhibits β adrenergic receptor-stimulated apoptosis in cardiomyoblasts. Here, we tested the hyposeis that canstatin regulates LTCCs activity in ventricular cardiomyocytes. Collagen type IV α2 chain (COL4A2) small interfering (si) RNA (for canstatin suppression) or control siRNA was injected via jugular vein in Wistar rats...
April 4, 2018: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/29619867/usefulness-of-pretransplant-aortic-arch-calcification-evaluation-for-kidney-transplant-outcome-prediction-in-one-year-follow-up
#12
Agne Laucyte-Cibulskiene, Evelina Boreikaite, Gediminas Aucina, Migle Gudynaite, Ilona Rudminiene, Sigita Anisko, Loreta Vareikiene, Liutauras Gumbys, Dileta Valanciene, Ligita Ryliskyte, Kestutis Strupas, Laurynas Rimsevicius, Marius Miglinas
Vascular calcification (VC) is linked to post-transplant cardiovascular events and hypercalcemia which may influence kidney graft function in the long term. We aimed to evaluate whether pretransplant aortic arch calcification (AoAC) can predict post-transplant cardiovascular or cerebrovascular events (CVEs), and to assess its association with post-transplant plasma calcium levels and renal function in one-year follow-up. Our single-center observational prospective study enrolled 37 kidney transplant recipients (KTR) without previous history of vascular events...
November 2018: Renal Failure
https://www.readbyqxmd.com/read/29589836/laser-induced-calcium-oscillations-in-fluorescent-calcium-imaging
#13
János Vincze, Nikolett Geyer, Gyula Diszházi, László Csernoch, Tamás Bíró, István Jóna, Beatrix Dienes, János Almássy
Phototoxicity is the most common problem investigators may encounter when performing live cell imaging. It develops due to excess laser exposure of cells loaded with fluorophores and can lead to often overlooked but significant artifacts, such as massive increase of intracellular Ca2+ concentration, which would make data interpretation problematic. Because information about laser- and dye-related changes in cytoplasmic calcium concentration is very limited, we aimed to describe this phenomenon to help investigators using laser scanning confocal microscopy in a non-invasive way...
March 28, 2018: General Physiology and Biophysics
https://www.readbyqxmd.com/read/29589390/high-brachial-ankle-pulse-wave-velocity-as-a-marker-for-predicting-coronary-artery-stenosis-in-patients-with-type-2-diabetes
#14
Bo Hyun Kim, Jae Sik Jang, Yong Seop Kwon, June Hyung Kim, In Joo Kim, Chang Won Lee
BACKGROUND: We evaluated the ability of brachial ankle pulse wave velocity (baPWV) to predict coronary artery stenosis (CAS) in patients with type 2 diabetes, and compared the predictive power of baPWV to that of well-known cardiovascular disease (CVD) risk calculators. METHODS: The study group included 83 consecutive patients over 30 years old with type 2 diabetes who complained of vague chest discomfort. An automatic pulse waveform analyzer was used to measure baPWV...
March 2018: Endocrinology and Metabolism
https://www.readbyqxmd.com/read/29574598/synchronized-roles-of-pannexin-and-connexin-in-nasal-mucosal-epithelia
#15
Toyoaki Ohbuchi, Hideaki Suzuki
BACKGROUND: Nasal mucosal epithelial cells express connexins, the prototypical gap junction proteins, and pannexins, a new family of channel proteins homologous to the invertebrate gap junction proteins. The physiological and pathophysiological roles of these transmembrane proteins in nasal mucosa are largely still unknown. PURPOSE: Pannexins participate in ATP release into the extracellular space in various tissues, and ATP plays important roles in mucociliary clearance, especially by regulating ciliary beat activity...
March 24, 2018: European Archives of Oto-rhino-laryngology
https://www.readbyqxmd.com/read/29563504/aux1-mediated-root-hair-auxin-influx-governs-scf-tir1-afb-type-ca-2-signaling
#16
Julian Dindas, Sönke Scherzer, M Rob G Roelfsema, Katharina von Meyer, Heike M Müller, K A S Al-Rasheid, Klaus Palme, Petra Dietrich, Dirk Becker, Malcolm J Bennett, Rainer Hedrich
Auxin is a key regulator of plant growth and development, but the causal relationship between hormone transport and root responses remains unresolved. Here we describe auxin uptake, together with early steps in signaling, in Arabidopsis root hairs. Using intracellular microelectrodes we show membrane depolarization, in response to IAA in a concentration- and pH-dependent manner. This depolarization is strongly impaired in aux1 mutants, indicating that AUX1 is the major transporter for auxin uptake in root hairs...
March 21, 2018: Nature Communications
https://www.readbyqxmd.com/read/29539417/excitatory-neuronal-hubs-configure-multisensory-integration-of-slow-waves-in-association-cortex
#17
Satoshi Kuroki, Takamasa Yoshida, Hidekazu Tsutsui, Mizuho Iwama, Reiko Ando, Takayuki Michikawa, Atsushi Miyawaki, Toshio Ohshima, Shigeyoshi Itohara
Multisensory integration (MSI) is a fundamental emergent property of the mammalian brain. During MSI, perceptual information encoded in patterned activity is processed in multimodal association cortex. The systems-level neuronal dynamics that coordinate MSI, however, are unknown. Here, we demonstrate intrinsic hub-like network activity in the association cortex that regulates MSI. We engineered calcium reporter mouse lines based on the fluorescence resonance energy transfer sensor yellow cameleon (YC2.60) expressed in excitatory or inhibitory neurons...
March 13, 2018: Cell Reports
https://www.readbyqxmd.com/read/29535566/functional-analysis-and-immunochemical-analyses-of-ca-2-homeostasis-related-proteins-expression-of-glaucoma-induced-retinal-degeneration-in-rats
#18
Ji-Yeon Lee, Su-Ja Oh
The retinal degeneration resulting from elevated intraocular pressure was evaluated through functional and morphological analyses, for better understanding of the pathophysiology of glaucoma. Ocular hypertension was induced via unilateral episcleral venous cauterization in rats. Experimental time was set at 1 and 3 days, and 1, 2, 4, and 8 weeks post-operation. Retinal function was analyzed using electroretinography. For morphological analysis, retinal tissues were processed for immunochemistry by using antibodies against the calcium-sensing receptor and calcium-binding proteins...
February 2018: Experimental Neurobiology
https://www.readbyqxmd.com/read/29531576/quantitative-assessment-of-the-physiological-parameters-influencing-qt-interval-response-to-medication-application-of-computational-intelligence-tools
#19
Sebastian Polak, Barbara Wiśniowska, Aleksander Mendyk, Adam Pacławski, Jakub Szlęk
Human heart electrophysiology is complex biological phenomenon, which is indirectly assessed by the measured ECG signal. ECG trace is further analyzed to derive interpretable surrogates including QT interval, QRS complex, PR interval, and T wave morphology. QT interval and its modification are the most commonly used surrogates of the drug triggered arrhythmia, but it is known that the QT interval itself is determined by other nondrug related parameters, physiological and pathological. In the current study, we used the computational intelligence algorithms to analyze correlations between various simulated physiological parameters and QT interval...
2018: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/29514100/coupling-of-rigor-mortis-and-intestinal-necrosis-during-c-elegans-organismal-death
#20
Evgeniy R Galimov, Rosina E Pryor, Sarah E Poole, Alexandre Benedetto, Zachary Pincus, David Gems
Organismal death is a process of systemic collapse whose mechanisms are less well understood than those of cell death. We previously reported that death in C. elegans is accompanied by a calcium-propagated wave of intestinal necrosis, marked by a wave of blue autofluorescence (death fluorescence). Here, we describe another feature of organismal death, a wave of body wall muscle contraction, or death contraction (DC). This phenomenon is accompanied by a wave of intramuscular Ca2+ release and, subsequently, of intestinal necrosis...
March 6, 2018: Cell Reports
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