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Sample records for acute electrophysiological experiments

  1. Clinical and electrophysiological parameters distinguishing acute-onset chronic inflammatory demyelinating polyneuropathy from acute inflammatory demyelinating polyneuropathy.

    PubMed

    Dionne, Annie; Nicolle, Michael W; Hahn, Angelika F

    2010-02-01

    Up to 16% of chronic inflammatory demyelinating polyneuropathy (CIDP) patients may present acutely. We performed a retrospective chart review on 30 acute inflammatory demyelinating polyneuropathy (AIDP) and 15 acute-onset CIDP (A-CIDP) patients looking for any clinical or electrophysiological parameters that might differentiate AIDP from acutely presenting CIDP. A-CIDP patients were significantly more likely to have prominent sensory signs. They were significantly less likely to have autonomic nervous system involvement, facial weakness, a preceding infectious illness, or need for mechanical ventilation. With regard to electrophysiological features, neither sural-sparing pattern, sensory ratio >1, nor the presence of A-waves was different between the two groups. This study suggests that patients presenting acutely with a demyelinating polyneuropathy and the aforementioned clinical features should be closely monitored as they may be more likely to have CIDP at follow-up.

  2. The electrophysiological examination in acute optic neuritis and during their recovery.

    PubMed

    Salu, P; Daniel, Y

    1990-01-01

    A survey of the electrophysiological methods will be given. We use this method to diagnose an optic neuritis and to evaluate it during its acute stage as well as during its recuperation. The importance of the contrast as stimulation parameter of the pattern VEP will be described, and its clinical relevance will be illustrated by a few clinical cases.

  3. Ganzfeld-induced hallucinatory experience, its phenomenology and cerebral electrophysiology.

    PubMed

    Wackermann, Jirí; Pütz, Peter; Allefeld, Carsten

    2008-01-01

    Ganzfeld, i.e., exposure to an unstructured, uniform stimulation field, elicits in most observers pseudo-hallucinatory percepts, and may even induce global functional state changes ('altered states of consciousness'). The present paper gives a comprehensive overview of the phenomenology of subjective experience in the ganzfeld and its electrophysiological correlates. Laboratory techniques for visual or multi-modal ganzfeld induction are explained. The spectrum of ganzfeld-induced phenomena, ranging from elementary percepts to complex, vivid, dream-like imagery is described, and the latter illustrated by transcripts of subjects' reports. Similarities and differences to related sensory/perceptual phenomena are also discussed. Earlier findings on electrophysiological correlates of the ganzfeld are reviewed. Our own studies of electroencephalographic (EEG) activity in the ganzfeld are presented in some detail, and a re-analysis of data on EEG correlates of hallucinatory percepts in statu nascendi is reported. The results do not support the hypothesis of the hypnagogic origin of the percepts; the ganzfeld-induced steady-state is an activated state, and the spectral EEG dynamics in the alpha frequency range reveals processes of attention shifts and percept formation. The final section is devoted to the controversial topic of allegedly anomalous communication between human subjects ('ganzfeld telepathy'). It is shown that the use of ganzfeld in this research field relies partly on unsupported hypotheses concerning ganzfeld-induced states, partly on a weak conceptual background of the experimental procedure. The rôle of a particular belief system shared by the participants and experimenters is critically discussed.

  4. Electrophysiological and Cognitive Evaluation of Abstinent Acute Alcoholics

    DTIC Science & Technology

    1991-12-01

    Defense, nor the U. S. Government. Summary Event-related potential ( ERP ) component parameters were used as dependent measures in an evaluation of the...functional aspects of cognition in acute alcoholics. Previous ERP studies indicated that chronic alcoholic subjects differ in unique ways from...treatment. The initial results of this study support the idea that alcoholism has a deleterious effect upon the ERPs of human subjectg. The reduced P300

  5. Laser blood irradiation effect on electrophysiological characteristics of acute coronary syndrome patients

    NASA Astrophysics Data System (ADS)

    Khotiaintsev, Sergei N.; Doger-Guerrero, E.; Glebova, L.; Svirid, V.; Sirenko, Yuri

    1996-11-01

    This paper treats electro-physiological effects of the low- level laser irradiation of blood (LBI). The data presented here are based on the observation of almost 200 patients suffering from the acute disruption of coronary blood circulation, unstable angina pectoris and myocardial infarction. Statistically significant changes of the electro-physiological characteristics were observed in the group of 65 patients, treated by the LBI. In particular, the significant 6 percent extension of the effective refractory period was observed. The electrical situation threshold has increased by 20.6 percent. The significant changes of some other important electro-physiological characteristics were within the range of 5-15 percent. In this paper, the data obtained on the LBI effectiveness are compared also with the results obtained on 94 patients who in addition to the standard anti-angina therapy were treated by the autohaemo- transfusion performed simultaneously with the UV-light irradiation of the transfused blood. The results obtained demonstrate the significant positive effect of the low energy LBI. The electrophysiological data obtained have good correlation with observed anti-arrhythmic effect of the LBI. This is proved by the data obtained on the electro- physiological characteristics of the cardiovascular system and by other clinical data on the experimental and control group of patients. In the course of this research the exact effect of the low level LBI was established. LBI led to the pronounced positive changes in electro-physiological characteristics of the cardiovascular system of the patients, it also led to the pronounced anti-arrhythmic effect.

  6. Electrophysiologic and behavioral effects of perinatal and acute exposure of rats to lead and polychlorinated biphenyls.

    PubMed Central

    Carpenter, David O; Hussain, Rifat J; Berger, David F; Lombardo, John P; Park, Hye-Youn

    2002-01-01

    Lead and polychlorinated biphenyls (PCBs) both cause a reduction of intelligence quotient and behavioral abnormalities in exposed children that have features in common with attention deficit hyperactivity disorder. We have used rats as a model to study the effects of both perinatal and acute exposure to lead or PCBs in an effort to compare and understand the mechanisms of these nervous system decrements. Long-term potentiation (LTP) is an electrophysiologic measurement that correlates well with cognitive ability. We have determined the effects of chronic perinatal exposure to lead or PCB 153 as well as acute application of these substances to isolated brain slices, with recordings in two areas of the hippocampus, CA1 and CA3. Both substances, whether chronically or acutely applied, significantly reduced LTP in CA1 in animals at age 30 and 60 days. In CA3, they reduced LTP in 30-day animals but potentiated it in 60-day animals. Although neither lead nor PCB 153 alters baseline synaptic transmission at low stimulus strengths, at higher levels they induce changes in the same direction as those of LTP. These results show surprisingly similar actions of these quite different chemicals, and the similarity of effects on chronic and acute application indicates that effects are both pharmacologic and developmental. Behavioral studies of rats exposed to PCBs from contaminated fish show hyperactivity, impulsiveness, and increased frustration relative to unexposed controls. These results demonstrate that lead and PCBs have similar effects on synaptic plasticity and behavior and suggest that the compounds may act through a common mechanism. PMID:12060832

  7. Acute electrophysiological effect of pulsed gallium-arsenide low-energy laser irradiation on isolated frog sciatic nerve.

    PubMed

    Cömelekoğlu, U; Bagiş, S; Büyükakilli, B; Sahin, G; Erdoğan, C; Kanik, A

    2002-01-01

    We evaluated the acute electrophysiological effects of low-energy pulsed laser irradiation on isolated frog sciatic nerve measured by extracellular recording technique. A pulsed gallium-arsenide (GaAs) laser (wavelength: 904 nm, pulse duration 220 ns, peak power per pulse: 27W, spot size: 0.28 cm(2), total applied energy density: 0.005-2.5J/cm(2)) was used for the experiment. Sixty isolated nerves were divided into six groups (n=10), each of which received a different laser dose. In each group, action potentials were recorded before laser irradiation which served as the control data. The extracellular action potentials were recorded for each combination of 1, 3, 5, 7, 10, 13 and 15 minutes of irradiation time and 4, 8, 16, 32, 64 and 128 repetition frequency by using a BIOPAC MP 100 Acquisition System Version 3.5.7 (Santa Barbara, USA). Action potential amplitude, area, duration and conduction velocity were measured. Statistical evaluation was performed using repeated measures variance analysis by SPSS 9.0. There were no statistically significant differences for action potential amplitude, area and conduction velocity among the laser groups and control data (p>0.05). The study showed that low-energy GaAs irradiation at 4-128 Hz repetition frequencies administered for irradiation times of 1-15 min generates no effect on action potential amplitude, area, duration and conduction velocity in isolated frog sciatic nerve.

  8. Electrophysiological profile of the new atypical neuroleptic, sertindole, on midbrain dopamine neurones in rats: acute and repeated treatment.

    PubMed

    Skarsfeldt, T

    1992-01-01

    Sertindole (Lundbeck code No. Lu 23-174) (1-[2-[4-[5-chloro-1-(4-fluorophenyl)-1H-indol-3-yl]-1-piperidinyl] ethyl]-2-imidazolidinone) is a new potential neuroleptic compound. After 3 weeks of treatment sertindole shows an extreme selectivity to inhibit the number of spontaneously active dopaminergic (DA) neurones in ventral tegmental area (VTA) while leaving the number of active DA neurones in substantia nigra pars compacta (SNC) unaffected. Acute injection of apomorphine or baclofen reverse the inhibition of activity seen after repeated treatment with sertindole. This suggests that sertindole induces a depolarization inactivation of the DA neurones. The depolarization inactivation is reversible since normal activity of DA neurones is found in both SNC and VTA after two weeks withdrawal from repeated treatment with a low dose with sertindole. One or two weeks administration of a high dose of sertindole induced only minor effects on the DA neurones in VTA; i.e., in order to obtain the depolarization inactivation sertindole requires 3 weeks of treatment as has also been reported for other neuroleptics. Three weeks of treatment with clozapine induces a selective inhibition of the active DA neurones in VTA but at much higher doses than seen with sertindole, while haloperidol induces a non-selective decrease of spontaneously active DA neurones in both areas. In acute electrophysiological experiments intravenous (i.v.) administration of sertindole--in contrast to both clozapine and haloperidol--neither reverse d-amphetamine- nor apomorphine-induced inhibition of the firing frequencies of DA neurones in SNC or in VTA. In addition, sertindole does not--even in high doses--increase the firing frequency of DA neurones in SNC or VTA.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Minimum Information about a Cardiac Electrophysiology Experiment (MICEE): standardised reporting for model reproducibility, interoperability, and data sharing.

    PubMed

    Quinn, T A; Granite, S; Allessie, M A; Antzelevitch, C; Bollensdorff, C; Bub, G; Burton, R A B; Cerbai, E; Chen, P S; Delmar, M; Difrancesco, D; Earm, Y E; Efimov, I R; Egger, M; Entcheva, E; Fink, M; Fischmeister, R; Franz, M R; Garny, A; Giles, W R; Hannes, T; Harding, S E; Hunter, P J; Iribe, G; Jalife, J; Johnson, C R; Kass, R S; Kodama, I; Koren, G; Lord, P; Markhasin, V S; Matsuoka, S; McCulloch, A D; Mirams, G R; Morley, G E; Nattel, S; Noble, D; Olesen, S P; Panfilov, A V; Trayanova, N A; Ravens, U; Richard, S; Rosenbaum, D S; Rudy, Y; Sachs, F; Sachse, F B; Saint, D A; Schotten, U; Solovyova, O; Taggart, P; Tung, L; Varró, A; Volders, P G; Wang, K; Weiss, J N; Wettwer, E; White, E; Wilders, R; Winslow, R L; Kohl, P

    2011-10-01

    Cardiac experimental electrophysiology is in need of a well-defined Minimum Information Standard for recording, annotating, and reporting experimental data. As a step towards establishing this, we present a draft standard, called Minimum Information about a Cardiac Electrophysiology Experiment (MICEE). The ultimate goal is to develop a useful tool for cardiac electrophysiologists which facilitates and improves dissemination of the minimum information necessary for reproduction of cardiac electrophysiology research, allowing for easier comparison and utilisation of findings by others. It is hoped that this will enhance the integration of individual results into experimental, computational, and conceptual models. In its present form, this draft is intended for assessment and development by the research community. We invite the reader to join this effort, and, if deemed productive, implement the Minimum Information about a Cardiac Electrophysiology Experiment standard in their own work.

  10. Emotion self-regulation, psychophysiological coherence, and test anxiety: results from an experiment using electrophysiological measures.

    PubMed

    Bradley, Raymond Trevor; McCraty, Rollin; Atkinson, Mike; Tomasino, Dana; Daugherty, Alane; Arguelles, Lourdes

    2010-12-01

    This study investigated the effects of a novel, classroom-based emotion self-regulation program (TestEdge) on measures of test anxiety, socioemotional function, test performance, and heart rate variability (HRV) in high school students. The program teaches students how to self-generate a specific psychophysiological state--psychophysiological coherence--which has been shown to improve nervous system function, emotional stability, and cognitive performance. Implemented as part of a larger study investigating the population of tenth grade students in two California high schools (N = 980), the research reported here was conducted as a controlled pre- and post-intervention laboratory experiment, using electrophysiological measures, on a random stratified sample of students from the intervention and control schools (N = 136). The Stroop color-word conflict test was used as the experiment's stimulus to simulate the stress of taking a high-stakes test, while continuous HRV recordings were gathered. The post-intervention electrophysiological results showed a pattern of improvement across all HRV measures, indicating that students who received the intervention program had learned how to better manage their emotions and to self-activate the psychophysiological coherence state under stressful conditions. Moreover, students with high test anxiety exhibited increased HRV and heart rhythm coherence even during a resting baseline condition (without conscious use of the program's techniques), suggesting that they had internalized the benefits of the intervention. Consistent with these results, students exhibited reduced test anxiety and reduced negative affect after the intervention. Finally, there is suggestive evidence from a matched-pairs analysis that reduced test anxiety and increased psychophysiological coherence appear to be directly associated with improved test performance--a finding consistent with evidence from the larger study.

  11. Electrophysiological and Morphological Characterization of Neuronal Microcircuits in Acute Brain Slices Using Paired Patch-Clamp Recordings

    PubMed Central

    Qi, Guanxiao; Radnikow, Gabriele; Feldmeyer, Dirk

    2015-01-01

    The combination of patch clamp recordings from two (or more) synaptically coupled neurons (paired recordings) in acute brain slice preparations with simultaneous intracellular biocytin filling allows a correlated analysis of their structural and functional properties. With this method it is possible to identify and characterize both pre- and postsynaptic neurons by their morphology and electrophysiological response pattern. Paired recordings allow studying the connectivity patterns between these neurons as well as the properties of both chemical and electrical synaptic transmission. Here, we give a step-by-step description of the procedures required to obtain reliable paired recordings together with an optimal recovery of the neuron morphology. We will describe how pairs of neurons connected via chemical synapses or gap junctions are identified in brain slice preparations. We will outline how neurons are reconstructed to obtain their 3D morphology of the dendritic and axonal domain and how synaptic contacts are identified and localized. We will also discuss the caveats and limitations of the paired recording technique, in particular those associated with dendritic and axonal truncations during the preparation of brain slices because these strongly affect connectivity estimates. However, because of the versatility of the paired recording approach it will remain a valuable tool in characterizing different aspects of synaptic transmission at identified neuronal microcircuits in the brain. PMID:25650985

  12. Towards a smart experimental arena for long-term electrophysiology experiments.

    PubMed

    Jow, Uei-Ming; Kiani, Mehdi; Huo, Xueliang; Ghovanloo, Maysam

    2012-10-01

    Wireless power and data transmission have created promising prospects in biomedical research by enabling perpetual data acquisition and stimulation systems. We present a work in progress towards such a system, called the EnerCage, equipped with scalable arrays of overlapping planar spiral coils (PSC) and 3-axis magnetic sensors for focused wireless power transmission to randomly moving targets, such as small freely behaving animal subjects. The EnerCage system includes a stationary unit for 3D non-line-of-sight localization and inductive power transmission through a geometrically optimized PSC array. The localization algorithm compares the magnetic sensor outputs with a threshold to activate a PSC. All PSCs are optimized based on the worst-case misalignment, considering parasitics from the overlapping and adjacent PSCs. EnerCage also has a mobile unit attached to or implanted in the subject's body, which includes a permanent magnetic tracer for localization and back telemetry circuit for efficient closed-loop inductive power regulation. The EnerCage system is designed to enable long-term electrophysiology experiments on freely behaving small animal subjects in large experimental arenas without requiring them to carry bulky batteries. A prototype of the EnerCage system with five PSCs and five magnetic sensors achieved power transfer efficiency (PTE) of 19.6% at the worst-case horizontal misalignment of 49.1 mm (√1/3 of the PSC radius) and coupling distance of 78 mm with a mobile unit coil, 20 mm in radius. The closed-loop power management mechanism maintains the mobile unit received power at 20 mW despite misalignments, tilting, and distance variations up to a maximum operating height of 120 mm (PTE = 5%).

  13. [Effectiveness of semax in acute period of hemispheric ischemic stroke (a clinical and electrophysiological study)].

    PubMed

    Gusev, E I; Skvortsova, V I; Miasoedov, N F; Nezavibat'ko, V N; Zhuravleva, E Iu; Vanichkin, A V

    1997-01-01

    Efficiency of Semax (synthetic derivative of ACTH-4-10) was studied in 30 patients in acute period of hemispherical ischemic stroke. Control group consisted of 80 patients with the strokes analogous in severity and location of the damages and which were treated by conventional therapy. Different clinical rating scales were used for both objectivization of the severity of the patients' state and estimation of the degree of neurological defect. The control of Semax influence on the functional state of the brain included monitoring of EEG with mapping, repeated analysis of somatosensory evoked potentials and their mapping. It was established that including of Semax in combined intensive therapy of acute ischemic stroke had some influence on the rate of restoration of the damaged neurological functions in terms of increasing the regress of general cerebral and focal, especially motor disorders. The most effective daily doses were 12 mg for patients with strokes of moderate severity and 18 mg for patients with severe strokes (treatment course--5 and 10 days).

  14. Instrumentation for fast-scan cyclic voltammetry combined with electrophysiology for behavioral experiments in freely moving animals

    PubMed Central

    Takmakov, Pavel; McKinney, Collin J.; Carelli, Regina M.; Wightman, R. Mark

    2011-01-01

    Fast-scan cyclic voltammetry is a unique technique for sampling dopamine concentration in the brain of rodents in vivo in real time. The combination of in vivo voltammetry with single-unit electrophysiological recording from the same microelectrode has proved to be useful in studying the relationship between animal behavior, dopamine release and unit activity. The instrumentation for these experiments described here has two unique features. First, a 2-electrode arrangement implemented for voltammetric measurements with the grounded reference electrode allows compatibility with electrophysiological measurements, iontophoresis, and multielectrode measurements. Second, we use miniaturized electronic components in the design of a small headstage that can be fixed on the rat's head and used in freely moving animals. PMID:21806203

  15. Instrumentation for fast-scan cyclic voltammetry combined with electrophysiology for behavioral experiments in freely moving animals.

    PubMed

    Takmakov, Pavel; McKinney, Collin J; Carelli, Regina M; Wightman, R Mark

    2011-07-01

    Fast-scan cyclic voltammetry is a unique technique for sampling dopamine concentration in the brain of rodents in vivo in real time. The combination of in vivo voltammetry with single-unit electrophysiological recording from the same microelectrode has proved to be useful in studying the relationship between animal behavior, dopamine release and unit activity. The instrumentation for these experiments described here has two unique features. First, a 2-electrode arrangement implemented for voltammetric measurements with the grounded reference electrode allows compatibility with electrophysiological measurements, iontophoresis, and multielectrode measurements. Second, we use miniaturized electronic components in the design of a small headstage that can be fixed on the rat's head and used in freely moving animals.

  16. The influence of acute stress on attention mechanisms and its electrophysiological correlates.

    PubMed

    Sänger, Jessica; Bechtold, Laura; Schoofs, Daniela; Blaszkewicz, Meinolf; Wascher, Edmund

    2014-01-01

    FOR THE SELECTION OF RELEVANT INFORMATION OUT OF A CONTINUOUS STREAM OF INFORMATION, WHICH IS A COMMON DEFINITION OF ATTENTION, TWO CORE MECHANISMS ARE ASSUMED: a competition-based comparison of the neuronal activity in sensory areas and the top-down modulation of this competition by frontal executive control functions. Those control functions are thought to bias the processing of information toward the intended goals. Acute stress is thought to impair these frontal functions through the release of cortisol. In the present study, subjects had to detect a luminance change of a stimulus and ignore more salient but task irrelevant orientation changes. Before the execution of this task, subjects underwent a socially evaluated cold pressor test (SECPT) or a non-stressful control situation. The SECPT revealed reliable stress response with a significant increase of cortisol and alpha-amylase. Stressed subjects showed higher error rates than controls, particularly in conditions which require top-down control processing to bias the less salient target feature against the more salient and spatially separated distracter. By means of the EEG, subjects who got stressed showed a reduced allocation to the relevant luminance change apparent in a modulation of the N1pc. The following N2pc, which reflects a re-allocation of attentional resources, supports the error pattern. There was only an N2pc in conditions, which required to bias the less salient luminance change. Moreover, this N2pc was decreased as a consequence of the induced stress. These results allow the conclusion that acute stress impairs the intention-based attentional allocation and enhances the stimulus-driven selection, leading to a strong distractibility during attentional information selection.

  17. The influence of acute stress on attention mechanisms and its electrophysiological correlates

    PubMed Central

    Sänger, Jessica; Bechtold, Laura; Schoofs, Daniela; Blaszkewicz, Meinolf; Wascher, Edmund

    2014-01-01

    For the selection of relevant information out of a continuous stream of information, which is a common definition of attention, two core mechanisms are assumed: a competition-based comparison of the neuronal activity in sensory areas and the top-down modulation of this competition by frontal executive control functions. Those control functions are thought to bias the processing of information toward the intended goals. Acute stress is thought to impair these frontal functions through the release of cortisol. In the present study, subjects had to detect a luminance change of a stimulus and ignore more salient but task irrelevant orientation changes. Before the execution of this task, subjects underwent a socially evaluated cold pressor test (SECPT) or a non-stressful control situation. The SECPT revealed reliable stress response with a significant increase of cortisol and alpha-amylase. Stressed subjects showed higher error rates than controls, particularly in conditions which require top-down control processing to bias the less salient target feature against the more salient and spatially separated distracter. By means of the EEG, subjects who got stressed showed a reduced allocation to the relevant luminance change apparent in a modulation of the N1pc. The following N2pc, which reflects a re-allocation of attentional resources, supports the error pattern. There was only an N2pc in conditions, which required to bias the less salient luminance change. Moreover, this N2pc was decreased as a consequence of the induced stress. These results allow the conclusion that acute stress impairs the intention-based attentional allocation and enhances the stimulus-driven selection, leading to a strong distractibility during attentional information selection. PMID:25346669

  18. Clinical neurological examination vs electrophysiological studies: Reflections from experiences in occupational medicine.

    PubMed

    Jepsen, Jørgen Riis

    2015-06-26

    Seventy-five percent of upper limb disorders that are related to work are regarded as diagnostically unclassifiable and therefore challenging to the clinician. Therefore it has been generally less successfully to prevent and treat these common and frequently disabling disorders. To reach a diagnosis requires the identification of the responsible pathology and the involved tissues and structures. Consequently, improved diagnostic approaches are needed. This editorial discusses the potentials of using the clinical neurologic examination in patients with upper limb complaints related to work. It is argued that a simple but systematic physical approach permits the examiner to frequently identify patterns of neurological findings that suggest nerve afflictions and their locations, and that electrophysiological studies are less likely to identify pathology. A diagnostic algorithm for the physical assessment is provided to assist the clinician. Failure to include representative neurological items in the physical examination may result in patients being misinterpreted, misdiagnosed and mistreated.

  19. A Novel Device to Suppress Electrical Stimulus Artifacts in Electrophysiological Experiments

    PubMed Central

    Wichmann, Thomas; Devergnas, Annaelle

    2011-01-01

    Electrophysiological studies of the effects of electrical brain stimulation have to contend with stimulus artifacts, which complicate both the maintenance of recorded neuron waveforms at recording time, and the post-hoc analysis of the data. The artifacts can be removed by digitally averaging some or all of the (stereotypic) artifact waveforms across artifacts, and then subtracting the resulting template from the recorded waveform at the time of artifact production. Available software-based approaches to this problem are effective but time consuming, and do not help with the problem of maintaining the recording quality at recording time. Alternative hardware-based methods are effective as well, but relatively inflexible and very expensive. We here provide a detailed description of a simple high-performance artifact removal device based on a multi-processor microcontroller as well as analog-to-digital and digital-to-analog converters. This device provides the benefits of self-adapting online-removal of stimulus artifacts for a fraction of the price of the commercially available devices. The device is fully customizable, and can be easily adjusted to various stimulation conditions, as well as AC line noise removal. PMID:21745499

  20. Human cardiac systems electrophysiology and arrhythmogenesis: iteration of experiment and computation.

    PubMed

    Holzem, Katherine M; Madden, Eli J; Efimov, Igor R

    2014-11-01

    Human cardiac electrophysiology (EP) is a unique system for computational modelling at multiple scales. Due to the complexity of the cardiac excitation sequence, coordinated activity must occur from the single channel to the entire myocardial syncytium. Thus, sophisticated computational algorithms have been developed to investigate cardiac EP at the level of ion channels, cardiomyocytes, multicellular tissues, and the whole heart. Although understanding of each functional level will ultimately be important to thoroughly understand mechanisms of physiology and disease, cardiac arrhythmias are expressly the product of cardiac tissue-containing enough cardiomyocytes to sustain a reentrant loop of activation. In addition, several properties of cardiac cellular EP, that are critical for arrhythmogenesis, are significantly altered by cell-to-cell coupling. However, relevant human cardiac EP data, upon which to develop or validate models at all scales, has been lacking. Thus, over several years, we have developed a paradigm for multiscale human heart physiology investigation and have recovered and studied over 300 human hearts. We have generated a rich experimental dataset, from which we better understand mechanisms of arrhythmia in human and can improve models of human cardiac EP. In addition, in collaboration with computational physiologists, we are developing a database for the deposition of human heart experimental data, including thorough experimental documentation. We anticipate that accessibility to this human heart dataset will further human EP computational investigations, as well as encourage greater data transparency within the field of cardiac EP.

  1. Human cardiac systems electrophysiology and arrhythmogenesis: iteration of experiment and computation

    PubMed Central

    Holzem, Katherine M.; Madden, Eli J.; Efimov, Igor R.

    2014-01-01

    Human cardiac electrophysiology (EP) is a unique system for computational modelling at multiple scales. Due to the complexity of the cardiac excitation sequence, coordinated activity must occur from the single channel to the entire myocardial syncytium. Thus, sophisticated computational algorithms have been developed to investigate cardiac EP at the level of ion channels, cardiomyocytes, multicellular tissues, and the whole heart. Although understanding of each functional level will ultimately be important to thoroughly understand mechanisms of physiology and disease, cardiac arrhythmias are expressly the product of cardiac tissue—containing enough cardiomyocytes to sustain a reentrant loop of activation. In addition, several properties of cardiac cellular EP, that are critical for arrhythmogenesis, are significantly altered by cell-to-cell coupling. However, relevant human cardiac EP data, upon which to develop or validate models at all scales, has been lacking. Thus, over several years, we have developed a paradigm for multiscale human heart physiology investigation and have recovered and studied over 300 human hearts. We have generated a rich experimental dataset, from which we better understand mechanisms of arrhythmia in human and can improve models of human cardiac EP. In addition, in collaboration with computational physiologists, we are developing a database for the deposition of human heart experimental data, including thorough experimental documentation. We anticipate that accessibility to this human heart dataset will further human EP computational investigations, as well as encourage greater data transparency within the field of cardiac EP. PMID:25362174

  2. Evaluation of the acute electrophysiologic effects of intravenous dronedarone, an amiodarone-like agent, with special emphasis on ventricular repolarization and acquired torsade de pointes arrhythmias.

    PubMed

    Verduyn, S C; Vos, M A; Leunissen, H D; van Opstal, J M; Wellens, H J

    1999-02-01

    In the anesthetized dog with complete chronic AV block (CAVB), we evaluated and compared the acute electrophysiologic effects of dronedarone i.v. (Dron, 2 times 2.5 mg/kg/10 min) and amiodarone i.v. (Amio, 2 times 5 mg/kg/10 min). This canine model with a high sensitivity for acquired torsade de pointes (TdP) provides an ideal substrate to evaluate ventricular repolarization abnormalities. Six ECG leads and two endocardial monophasic action potential (MAP) recordings in the left and right ventricle (LV and RV) were simultaneously recorded to measure QT time, action-potential duration (APD), interventricular dispersion (deltaAPD = LV(APD) - RV(APD)), early afterdepolarizations (EADs), ectopic beats (EBs), and TdP. Measurements were made at the spontaneous idioventricular rhythm (IVR) and 1,000-ms steady-state pacing. To investigate its short-term, antiarrhythmic properties, Dron was given after almokalant (0.12 mg/kg)-induced TdP. Furthermore, in another set of experiments, oral Dron (20 mg/kg, b.i.d) was given for 3 weeks to conscious CAVB dogs. Dron, i.v., shortened ventricular repolarization (QT, 435 +/- 60 to 360 +/- 55; LV(APD) 395 +/- 75 to 335 +/- 60 ms; p < 0.05), whereas IVR and ventricular effective refractory period (VERP, 225 +/- 30 to 230 +/- 30 ms) remained similar. Therefore the VERP/QT ratio increased (0.55 +/- 0.04 to 0.61 +/- 0.03; p < 0.05). Similar results were obtained with Amio, i.v.. Almokalant-induced TdP was characterized by an increased repolarization duration, deltaAPD, and EADs. Dron, i.v., suppressed the EADs, EBs, and TdP by a reduction and homogenization of repolarization (LV(APD), 505 +/- 110 to 455 +/- 80 ms, and deltaAPD, 110 +/- 55 to 65 +/- 40 ms). Long-term oral Dron increased the PP interval, CL-IVR, and QT(c) time. In contrast to oral treatment, Dron i.v. shortens ventricular repolarization parameters, resulting in suppression of EAD-dependent acquired TdP. The increased VERP/QT ratio after Dron i.v. may indicate an important

  3. Evaluating Aesthetic Experience through Personal-Appearance Styles: A Behavioral and Electrophysiological Study

    PubMed Central

    Cheung, Mei-chun; Law, Derry; Yip, Joanne

    2014-01-01

    Consumers' aesthetic experience has often been linked with the concept of beauty, which is regarded as subjective and may vary between individuals, cultures and places, and across time. With the advent of brain-imaging techniques, there is more and more evidence to suggest that aesthetic experience lies not only in the eye of the beholder, but also in the brain of the beholder. However, there are gaps in the previous research in this area, as several significant issues have not yet been addressed. Specifically, it is unclear whether the human brain really pays more attention and generates more positive emotional responses to beautiful things. To explore the brain activity relating to consumers' aesthetic experiences, 15 participants were recruited voluntarily to view a series of personal-appearance styles. They were invited to make aesthetic judgments while their brain activity was recorded by electroencephalography. Two electroencephalographic (EEG) indicators, theta coherence and frontal alpha symmetry, were utilized. Theta coherence is a measure of linear synchronization between signals at two electrode sites. It reflects the degree of functional cooperation between the underlying neuronal substrates and was used to explore the attentional processing involved in aesthetic judgments. Frontal alpha asymmetry is derived by subtracting the log-transformed absolute alpha power of the left hemisphere from the analogous log-transformed alpha power of the right hemisphere. It was used as an indicator of emotional response. During aesthetic judgments, long-range theta coherence increased in both hemispheres and more positive frontal alpha asymmetry was found when the styles were judged to be beautiful. Therefore, participants demonstrated brain activity suggestive of central executive processing and more positive emotional responses when they considered styles to be beautiful. The study provides some insight into the brain activity associated with consumers' aesthetic

  4. When early experiences build a wall to others' emotions: an electrophysiological and autonomic study.

    PubMed

    Ardizzi, Martina; Martini, Francesca; Umiltà, Maria Alessandra; Sestito, Mariateresa; Ravera, Roberto; Gallese, Vittorio

    2013-01-01

    Facial expression of emotions is a powerful vehicle for communicating information about others' emotional states and it normally induces facial mimicry in the observers. The aim of this study was to investigate if early aversive experiences could interfere with emotion recognition, facial mimicry, and with the autonomic regulation of social behaviors. We conducted a facial emotion recognition task in a group of "street-boys" and in an age-matched control group. We recorded facial electromyography (EMG), a marker of facial mimicry, and respiratory sinus arrhythmia (RSA), an index of the recruitment of autonomic system promoting social behaviors and predisposition, in response to the observation of facial expressions of emotions. Results showed an over-attribution of anger, and reduced EMG responses during the observation of both positive and negative expressions only among street-boys. Street-boys also showed lower RSA after observation of facial expressions and ineffective RSA suppression during presentation of non-threatening expressions. Our findings suggest that early aversive experiences alter not only emotion recognition but also facial mimicry of emotions. These deficits affect the autonomic regulation of social behaviors inducing lower social predisposition after the visualization of facial expressions and an ineffective recruitment of defensive behavior in response to non-threatening expressions.

  5. LANGUAGE EXPERIENCE SHAPES PROCESSING OF PITCH RELEVANT INFORMATION IN THE HUMAN BRAINSTEM AND AUDITORY CORTEX: ELECTROPHYSIOLOGICAL EVIDENCE

    PubMed Central

    Krishnan, Ananthanarayan; Gandour, Jackson T.

    2015-01-01

    Pitch is a robust perceptual attribute that plays an important role in speech, language, and music. As such, it provides an analytic window to evaluate how neural activity relevant to pitch undergo transformation from early sensory to later cognitive stages of processing in a well coordinated hierarchical network that is subject to experience-dependent plasticity. We review recent evidence of language experience-dependent effects in pitch processing based on comparisons of native vs. nonnative speakers of a tonal language from electrophysiological recordings in the auditory brainstem and auditory cortex. We present evidence that shows enhanced representation of linguistically-relevant pitch dimensions or features at both the brainstem and cortical levels with a stimulus-dependent preferential activation of the right hemisphere in native speakers of a tone language. We argue that neural representation of pitch-relevant information in the brainstem and early sensory level processing in the auditory cortex is shaped by the perceptual salience of domain-specific features. While both stages of processing are shaped by language experience, neural representations are transformed and fundamentally different at each biological level of abstraction. The representation of pitch relevant information in the brainstem is more fine-grained spectrotemporally as it reflects sustained neural phase-locking to pitch relevant periodicities contained in the stimulus. In contrast, the cortical pitch relevant neural activity reflects primarily a series of transient temporal neural events synchronized to certain temporal attributes of the pitch contour. We argue that experience-dependent enhancement of pitch representation for Chinese listeners most likely reflects an interaction between higher-level cognitive processes and early sensory-level processing to improve representations of behaviorally-relevant features that contribute optimally to perception. It is our view that long

  6. The interactive effects of physical fitness and acute aerobic exercise on electrophysiological coherence and cognitive performance in adolescents.

    PubMed

    Hogan, Michael; Kiefer, Markus; Kubesch, Sabine; Collins, Peter; Kilmartin, Liam; Brosnan, Méadhbh

    2013-08-01

    The current study examined the effects of physical fitness and aerobic exercise on cognitive functioning and coherence of the electroencephalogram in 30 adolescents between the ages of 13 and 14 years. Participants were first classified as fit or unfit and then performed a modified Eriksen flanker task after a bout of acute exercise and after a period of relaxation. Analysis of behavioural differences between the fit and unfit groups revealed an interaction between fitness levels and acute physical exercise. Specifically, fit participants had significantly faster reaction times in the exercise condition in comparison with the rest condition; unfit, but not fit, participants had higher error rates for NoGo relative to Go trials in the rest condition. Furthermore, unfit participants had higher levels of lower alpha, upper alpha, and beta coherence in the resting condition for NoGo trials, possibly indicating a greater allocation of cognitive resources to the task demands. The higher levels of alpha coherence are of particular interest in light of its reported role in inhibition and effortful attention. The results suggest that physical fitness and acute exercise may enhance cognition by increasing the efficacy of the attentional system.

  7. [Clinical-electrophysiological characteristics of the cognitive sphere in patients in the acute period of the first cerebral ischemic stroke].

    PubMed

    Kispaeva, T T; Kichuk, I V; Shetova, I M; Memetova, D Sh; Gudkova, V V; Ivanova, G E; Skvortsova, V I

    2011-01-01

    A neuropsychological and neurophysiological study using computed EEG was carried out in 31 stroke patients who did not have a cognitive impairment according to MMSE. Thirty age-matched patients with the same risk factors without a history of stroke were included into the control group. The examination of the control group was performed only once. The examination of stroke patients was performed on days 1, 7 and 21. It was shown that cognitive neurodynamic disturbances (memory disorders and the visual memory decrease) and bioelectrical brain activity disturbances (the decrease in a- and beta band activities and the increase of theta-band power) occurred from the first day and lasted during the acute stroke period even after the improvement of neurological status.

  8. Effects of acute and long-term administration of escitalopram and citalopram on serotonin neurotransmission: an in vivo electrophysiological study in rat brain.

    PubMed

    El Mansari, Mostafa; Sánchez, Connie; Chouvet, Guy; Renaud, Bernard; Haddjeri, Nasser

    2005-07-01

    The present study was undertaken to compare the acute and long-term effects of escitalopram and citalopram on rat brain 5-HT neurotransmission, using electrophysiological techniques. In hippocampus, after 2 weeks of treatment with escitalopram (10 mg/kg/day, s.c.) or citalopram (20 mg/kg/day, s.c.), the administration of the selective 5-HT(1A) receptor antagonist WAY-100,635 (20-100 microg/kg, i.v.) dose-dependently induced a similar increase in the firing activity of dorsal hippocampus CA(3) pyramidal neurons, thus revealing direct functional evidence of an enhanced tonic activation of postsynaptic 5-HT(1A) receptors. In dorsal raphe nucleus, escitalopram was four times more potent than citalopram in suppressing the firing activity of presumed 5-HT neurons (ED(50)=58 and 254 mug/kg, i.v., respectively). Interestingly, the suppressant effect of escitalopram (100 microg/kg, i.v.) was significantly prevented, but not reversed by R-citalopram (250 microg/kg, i.v.). Sustained administration of escitalopram and citalopram significantly decreased the spontaneous firing activity of presumed 5-HT neurons. This firing activity returned to control rate after 2 weeks in rats treated with escitalopram, but only after 3 weeks using citalopram, and was associated with a desensitization of somatodendritic 5-HT(1A) autoreceptors. These results suggest that the time course of the gradual return of presumed 5-HT neuronal firing activity, which was reported to account for the delayed effect of SSRI on 5-HT transmission, is congruent with the earlier onset of action of escitalopram vs citalopram in validated animal models of depression and anxiety.

  9. The clinical experience of acute cyanide poisoning.

    PubMed

    Yen, D; Tsai, J; Wang, L M; Kao, W F; Hu, S C; Lee, C H; Deng, J F

    1995-09-01

    The authors reviewed the clinical manifestations, complications, and the prognosis affected by Lilly Cyanide Antidote in 21 victims of acute cyanide poisoning over a 10-year period. The clinical signs and symptoms in cyanide poisoning are variable. Among 21 cases, loss of consciousness (15), metabolic acidosis (14), and cardiopulmonary failure (9) were the three leading manifestations of cyanide intoxication. Anoxic encephalopathy (6) was not uncommon in the severely intoxicated victims. Diabetes insipidus (1) or clinical signs and symptoms mimicking diabetes insipidus (3) may be an ominous sign to encephalopathy victims. The major cause of fatal cyanide poisoning is the intentional ingestion of cyanide compounds as part of a suicide attempt. Decrease of arteriovenous difference of O2 partial pressure may be a clue for the suspicion of cyanide intoxication. Although the authors cannot show a statistically significant difference (P = .47) for the Lilly cyanide antidote kit in terms of improving the survival rate for victims of cyanide poisoning, the antidote kit was always mandatory in our study in the cases of severely intoxicated victims who survived. Early diagnosis, prompt, intensive therapy with antidote, and supportive care are still the golden rules for the treatment of acute cyanide poisoning, whether in the ED or on the scene.

  10. Acute renal failure in pregnancy: our experience.

    PubMed

    Aggarwal, Rohina S; Mishra, Vineet V; Jasani, Anil F; Gumber, Manoj

    2014-03-01

    Acute renal failure (ARF) is a serious medical complication during pregnancy, and, in the post-partum period, is associated with significant maternal morbidity and mortality as well as fetal loss. The objective of our study is to find the etiology and maternal outcome of ARF during pregnancy. The study was conducted at the Obstetrics and Gynecology Department of the Institute of Kidney Disease and Research Center, Ahmedabad, India from January 2009 to January 2011. Fifty previously healthy patients who developed ARF, diagnosed on oliguria and serum creatinine >2 mg%, were included in the study. Patients with a known history of renal disease, diabetes and hypertension were excluded from the study. All patients were followed-up for a period of six months. Patient re-cords, demographic data, urine output on admission and preceding history of antepartum hemorrhage (APH), post-partum hemorrhage (PPH), septicemia, operative interventions and retained product of conception were noted and need for dialysis was considered. Patients were thoroughly examined and baseline biochemical investigations and renal and obstetrical ultrasound were performed on each patient and bacterial culture sensitivity on blood, urine or vaginal swabs were performed in selected patients. The age range was 19-38 years (mean 26 ± 3.8). The first trimester, second trimester and puerperal groups comprised of four (8%), 25 (50%) and 21 patients (42%), respectively. Hemorrhage was the etiology for ARF in 15 (30%), APH in ten (20%) and PPH in five (10%) patients. Eleven (22%) patients had lower segment cesarian section (LSCS) while 36 (78%) patients had normal vaginal delivery. In 20 (40%) patients, puerperal sepsis was the etiological factor, while pre-eclampsia, eclampsia and HELLP syndrome accounted for 18 (36%) patients. Two (4%) patients had disseminated intravascular coagulation on presentation while one (2%) patient was diagnosed with hemolytic uremic syndrome. Maternal mortality was 12% (n = 6

  11. A microscopic setup for combined, and time-coordinated electrophysiological and confocal fluorescence microscopic experiments on neurons in living brain slices

    NASA Astrophysics Data System (ADS)

    Helm, P. J.

    1996-02-01

    In this paper, a microscopic system for cell physiological research is presented. The setup which is to a large extent based on commercially available products was designed to establish a platform for time-coordinated electrophysiological and fluorescence optical compound experiments on living neurons in brain slices. Instruments for infrared differential interference contrast video microscopy (IRDICM), confocal scanning laser microscopy (CSLM), and for patch clamp studies have been assembled into one unit. Using the IRDICM equipment, a neuron can be patched somatically and dendritically. Loading the neuron with a Ca2+ indicating dye substance can be examined epifluorescence optically using the Hg lamp or Xe lamp of the microscope. A stimulus initiating the propagation of an action potential through a dendrite can be synchronized to the electronic control unit of the CSLM, and changes in the concentration of Ca2+ in the dendrite can be recorded in a time-coordinated way. The setup has been used successfully in order to study in vitro the dynamics of intracellular Ca2+ in the dendritic system of living neurons in brain slices.

  12. “Reality” of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study

    PubMed Central

    Palmieri, Arianna; Calvo, Vincenzo; Kleinbub, Johann R.; Meconi, Federica; Marangoni, Matteo; Barilaro, Paolo; Broggio, Alice; Sambin, Marco; Sessa, Paola

    2014-01-01

    The nature of near-death-experiences (NDEs) is largely unknown but recent evidence suggests the intriguing possibility that NDEs may refer to actually “perceived,” and stored, experiences (although not necessarily in relation to the external physical world). We adopted an integrated approach involving a hypnosis-based clinical protocol to improve recall and decrease memory inaccuracy together with electroencephalography (EEG) recording in order to investigate the characteristics of NDE memories and their neural markers compared to memories of both real and imagined events. We included 10 participants with NDEs, defined by the Greyson NDE scale, and 10 control subjects without NDE. Memories were assessed using the Memory Characteristics Questionnaire. Our hypnosis-based protocol increased the amount of details in the recall of all kind of memories considered (NDE, real, and imagined events). Findings showed that NDE memories were similar to real memories in terms of detail richness, self-referential, and emotional information. Moreover, NDE memories were significantly different from memories of imagined events. The pattern of EEG results indicated that real memory recall was positively associated with two memory-related frequency bands, i.e., high alpha and gamma. NDE memories were linked with theta band, a well-known marker of episodic memory. The recall of NDE memories was also related to delta band, which indexes processes such as the recollection of the past, as well as trance states, hallucinations, and other related portals to transpersonal experience. It is notable that the EEG pattern of correlations for NDE memory recall differed from the pattern for memories of imagined events. In conclusion, our findings suggest that, at a phenomenological level, NDE memories cannot be considered equivalent to imagined memories, and at a neural level, NDE memories are stored as episodic memories of events experienced in a peculiar state of consciousness. PMID:24994974

  13. Advances in Electrophysiological Research

    PubMed Central

    Kamarajan, Chella; Porjesz, Bernice

    2015-01-01

    Electrophysiological measures of brain function are effective tools to understand neurocognitive phenomena and sensitive indicators of pathophysiological processes associated with various clinical conditions, including alcoholism. Individuals with alcohol use disorder (AUD) and their high-risk offspring have consistently shown dysfunction in several electrophysiological measures in resting state (i.e., electroencephalogram) and during cognitive tasks (i.e., event-related potentials and event-related oscillations). Researchers have recently developed sophisticated signal-processing techniques to characterize different aspects of brain dynamics, which can aid in identifying the neural mechanisms underlying alcoholism and other related complex disorders. These quantitative measures of brain function also have been successfully used as endophenotypes to identify and help understand genes associated with AUD and related disorders. Translational research also is examining how brain electrophysiological measures potentially can be applied to diagnosis, prevention, and treatment. PMID:26259089

  14. Electrophysiological Endophenotypes for Schizophrenia

    PubMed Central

    Owens, Emily; Bachman, Peter; Glahn, David C; Bearden, Carrie E

    2016-01-01

    Endophenotypes are quantitative, heritable traits that may help to elucidate the pathophysiologic mechanisms underlying complex disease syndromes, such as schizophrenia. They can be assessed at numerous levels of analysis; here, we review electrophysiological endophenotypes that have shown promise in helping us understand schizophrenia from a more mechanistic point of view. For each endophenotype, we describe typical experimental procedures, reliability, heritability, and reported gene and neurobiological associations. We discuss recent findings regarding the genetic architecture of specific electrophysiological endophenotypes, as well as converging evidence from EEG studies implicating disrupted balance of glutamatergic signaling and GABA-ergic inhibition in the pathophysiology of schizophrenia. We conclude that refining the measurement of electrophysiological endophenotypes, expanding genetic association studies, and integrating datasets are important next steps for understanding the mechanisms that connect identified genetic risk loci for schizophrenia to the disease phenotype. PMID:26954597

  15. Laparoscopic necrosectomy in acute necrotizing pancreatitis: Our experience

    PubMed Central

    Mathew, Mittu John; Parmar, Amit Kumar; Sahu, Diwakar; Reddy, Prasanna Kumar

    2014-01-01

    CONTEXT: Pancreatic necrosis is a local complication of acute pancreatitis. The development of secondary infection in pancreatic necrosis is associated with increased mortality. Pancreatic necrosectomy is the mainstay of invasive management. AIMS: Surgical approach has significantly changed in the last several years with the advent of enhanced imaging techniques and minimally invasive surgery. However, there have been only a few case series related to laparoscopic approach, reported in literature to date. Herein, we present our experience with laparoscopic management of pancreatic necrosis in 28 patients. MATERIALS AND METHODS: A retrospective study of 28 cases [20 men, 8 women] was carried out in our institution. The medical record of these patients including history, clinical examination, investigations, and operative notes were reviewed. The mean age was 47.8 years [range, 23-70 years]. Twenty-one patients were managed by transgastrocolic, four patients by transgastric, two patients by intra-cavitary, and one patient by transmesocolic approach. RESULTS: The mean operating time was 100.8 min [range, 60-120 min]. The duration of hospital stay after the procedure was 10-18 days. Two cases were converted to open (7.1%) because of extensive dense adhesions. Pancreatic fistula was the most common complication (n = 8; 28.6%) followed by recollection (n = 3; 10.7%) and wound infection (n = 3; 10.7%). One patient [3.6%] died in postoperative period. CONCLUSIONS: Laparoscopic pancreatic necrosectomy is a promising and safe approach with all the benefits of minimally invasive surgery and is found to have reduced incidence of major complications and mortality. PMID:25013328

  16. Acute movement disorders in children: experience from a developing country.

    PubMed

    Goraya, Jatinder Singh

    2015-03-01

    We describe acute movement disorders in 92 children, aged 5 days to 15 years, from an Indian tertiary hospital. Eighty-nine children had hyperkinetic movement disorders, with myoclonus in 25, dystonia in 21, choreoathetosis in 19, tremors in 15, and tics in 2. Tetany and tetanus were seen in 5 and 2 children, respectively. Hypokinetic movement disorders included acute parkinsonism in 3 children. Noninflammatory and inflammatory etiology were present in 60 and 32 children, respectively. Benign neonatal sleep myoclonus in 16 and opsoclonus myoclonus syndrome in 7 accounted for the majority of myoclonus cases. Vitamin B12 deficiency in 13 infants was the most common cause of tremors. Rheumatic fever and encephalitis were the most common causes of acute choreoathetosis. Acute dystonia had metabolic etiology in 6 and encephalitis and drugs in 3 each. Psychogenic movement disorders were seen in 4 cases only, although these patients may be underreported.

  17. ACUTE HEPATIC PORPHYRIA AND PSYCHOSES: (Experience of twelve years)1

    PubMed Central

    Golechha, G.R.

    1989-01-01

    SUMMARY A sample of 805 psychotic patients belonging to different groups was screened for acute hepatic porphyria during 1975 to 1987 by observing urinary colour change on standing to brown red colour and for positive Waston-Schwartz test, indicating increase in urinary porphobilinogen which is diagnostic of acute hepatic porphyria. 27.95% cases had shown positivity which was further confirmed by quantitative estimation using spectrophotometric method of Rimington. However, when these positive cases were subjected to more specific tests viz, additional butanol extraction modification to Watson-Schwartz test and quantitative estimation of porphobilinogen by ion-exchange resin coloumn chromatographic method of Mauzerall & Grannick, only 1.12% could confirm their positivity. These cases were only, diagnosed as acute hepatic porphyria. The positivity to the non specific, yet accepted diagnostic tests for acute porphyria observed in remaining 26.8% psychotics was an amazing unexplained phenomenon. It was suggestive of the presence of a non specific porphyric activity. PMID:21927409

  18. Abdominal Tuberculosis with an Acute Abdomen: Our Clinical Experience

    PubMed Central

    Dey, Ramprasad; Bhattacharya, Ujjwal

    2014-01-01

    Introduction: Tuberculosis is an important cause of morbidity in India. Abdominal Tuberculosis is a great mimicker and is difficult to diagnose. This prospective observational study is based on those patients who were diagnosed to be suffering from Abdominal Tuberculosis only after they presented with an acute abdomen. This study aims to document the nature of different types of acute presentation in Abdominal Tuberculosis according to involved sites and surgical pathology. The study also discusses the indications and extent of surgical intervention. Materials and Methods: Seventy new cases of Abdominal Tuberculosis (out of 718 cases of acute abdomen) were diagnosed and treated over a period of three years in the surgical ward of Calcutta National Medical College. Macroscopic appearance of abdominal tissues during surgery suggested the diagnosis of tuberculosis. The diagnosis was confirmed by histopathology and tissue culture. All patients were subsequently treated with a full course of antitubercular drugs (ATD). Results: The clinical presentations of acute abdomen included acute intestinal obstruction, perforative peritonitis and acute appendicitis etc. Terminal ileum and ileocaecal region were predominantly involved. The most common pathology was intestinal stricture with or without perforation. Most of the patients (approx 78.5%) required emergency surgery as a therapeutic intervention. A two-stage procedure was preferred in peritonitis and sepsis. Most of the remaining patients (12.8%) required surgery after initial conservative treatment for the first few days. Undiagnosed Abdominal Tuberculosis represents a notable percentage (10%) of patients who present with an acute abdomen as a surgical emergency. Conclusion: Abdominal Tuberculosis is very difficult to diagnose and diagnosis is often delayed till an acute abdomen is presented with. Almost all patients needed surgical intervention. Irrespective of surgery, all patients of abdominal tuberculosis require a

  19. [Our experiences in the treatment of acute leukemias].

    PubMed

    Jelić, S; Dragović, M; Vidaković, B; Plecas, V

    1976-01-01

    This paper deals with observations concerning treatment of acute leukemia in the Department of haematology of The Clinical hospital of Belgrade during the period from 1970 to 1975, and with results of the treatment itself. During the last five years, 27 patients with different types of acute leukemia were treated. The type of acute leukemia was determined using cytological criteria of Levy and Lortholary and cytochemical criteria as described by Hayhoe. One thrid of the patients died during the first days of hospitalisation, before any effect of cytostatic treatment could be evaluated. The cause of death in those patients was septic shock, intracranial haemorrhage or cardiovascular colapsus; initial signs of those complications of acute leukemia were allready present before diagnosis. Those data point to the fact that diagnosis of acute leukemia is often made too late, when irreversible ocmplications of the disease are allready established. Patients over sixty, often "fragile" to aggresive cytostatic therapy, may enter complete and relatively long lasting remission with induction therapy cosisting of 6-mercaptopurine and methotrexate only. Allthough the number of cases was rather limited, the authors had rather disappointing results with the 06-LA-66 protocole in adult lymphoblastic leukemia. The first with COAP treatment protocole seem encouraging. Adequate cytostatic therapy was in several cases impossible, duo to the lack of adequate substitution therapy; such inadequate cytostatic therapy resulted in partial remissions with a rather poor quality survival. A beeter cooperation is needed between hospital centers and institutions which provide matherial for the substitution theapy.

  20. Electrophysiological studies in alcoholism

    PubMed Central

    Blackstock, Eileen; Rushworth, Geoffrey; Gath, Dennis

    1972-01-01

    Using a range of electrophysiological techniques, it has been possible to demonstrate impaired function in smaller calibre motor fibres and in distal large cutaneous sensory nerve fibres in both alcoholic patients without neuropathy and in those alcoholics with clinical manifestations of peripheral nerve disease. Evidence of more proximal involvement of Ia sensory fibres was obtained, but in the majority of our patients, large motor fibres functioned normally. The nature of the underlying pathological process is discussed. Images PMID:4338445

  1. [Professor WU Xu's clinical experiences on acupuncture for acute upper abdominal pain].

    PubMed

    Wu, Xiao-Liang; Lu, Bin; Sun, Jian-Hua; Ai, Bing-Wei; Bao, Chao; Wu, Wen-Zhong; Li, Jian-Bing; Liu, Lan-Ying; Wu, Wen-Yun; Pei, Li-Xia; Zhou, Jun-Ling; Li, Yan-Cai; Qin, Shan

    2014-03-01

    The clinical experiences and proven cases of distinguished doctor of TCM, professor WU Xu, on acupuncture for acute upper abdominal pain is introduced. Professor WU's manipulation characteristics of acupuncture for acute upper abdominal pain, including acute cholecystitis, kidney stone, acute stomach pain, are one-hand shape but both hands in nature, moving like Tai Chi, force on the tip of needle, movement of qi mainly. The main technique posture is one-hand holding needle with middle finger for pressing, the needle is hold by thumb and index finger, and is assisted by middle finger. The special acupuncture experience of emergency is treatment according to syndrome differentiation, combination of acupuncture and moxibustion, selecting acupoint based on experience, blood-letting acupuncture therapy and so on.

  2. Rivaroxaban Rebound Acute Coronary Event: A Post Marketing Experience

    PubMed Central

    Agarwal, Ajay; Patel, Amish; Mufti, Omar; Jbara, Yaser; Jabbar, Ali Abdul

    2013-01-01

    We present a 65-year-old male who received rivaroxaban therapy prior to and after left knee replacement surgery. The patient developed generalized weakness soon after stopping rivaroxaban. An electrocardiogram showed acute infero-lateral ischemia and an echocardiogram reported an akinetic antero-apical wall segment, an apical clot and a reduced systolic function. A subsequent coronary angiogram revealed two-vessel coronary artery thrombosis. The case illustrates a temporal relationship of coronary thrombosis following rivaroxaban cessation.

  3. [Acute kidney injury and septic shock: experiences in treatment].

    PubMed

    Pozzato, Marco; Ferrari, Fiorenza; Livigni, Sergio; Quarello, Francesco

    2012-01-01

    Acute kidney injury (AKI) occurs in 5-45% of critically ill patients, and renal replacement therapy (RRT) is required in 4-10% of patients with AKI. AKI has long been considered to be hemodynamic damage from low blood flow resulting in shock, and efforts have been made to prevent and cure it by increasing the renal blood flow and improving the cardiac output and perfusion pressure. In recent years, new experimental studies on patients with septic AKI have shown that the renal blood flow remains unaltered or even increases in septic shock. An important mechanism in the pathophysiology of sepsis and septic shock appears to be apoptosis rather than ischemic necrosis. The type of treatment as well as the dose and timing of initiation of RRT seem to have strategic importance in the recovery of AKI in patients admitted to the ICU. In critically ill (often postsurgical and septic) patients with acute renal failure the use of new anticoagulation strategies has permitted to perform treatments for a sufficient number of hours to achieve the correct level of purification by minimizing the downtime and the bleeding risk. In our center the use of protocols for different methods and different types of anticoagulants has simplified the treatment of all patients with AKI and septic shock admitted to the ICU.

  4. Applying microfluidics to electrophysiology.

    PubMed

    Eddington, David T

    2007-01-01

    Microfluidics can be integrated with standard electrophysiology techniques to allow new experimental modalities. Specifically, the motivation for the microfluidic brain slice device is discussed including how the device docks to standard perfusion chambers and the technique of passive pumping which is used to deliver boluses of neuromodulators to the brain slice. By simplifying the device design, we are able to achieve a practical solution to the current unmet electrophysiology need of applying multiple neuromodulators across multiple regions of the brain slice. This is achieved by substituting the standard coverglass substrate of the perfusion chamber with a thin microfluidic device bonded to the coverglass substrate. This was then attached to the perfusion chamber and small holes connect the open-well of the perfusion chamber to the microfluidic channels buried within the microfluidic substrate. These microfluidic channels are interfaced with ports drilled into the edge of the perfusion chamber to access and deliver stimulants. This project represents how the field of microfluidics is transitioning away from proof-of concept device demonstrations and into practical solutions for unmet experimental and clinical needs.

  5. Electrophysiological Characteristics of Fetal Atrioventricular Block

    PubMed Central

    Zhao, Hui; Cuneo, Bettina F.; Strasburger, Janette F.; Huhta, James C.; Gotteiner, Nina L.; Wakai, Ronald T.

    2012-01-01

    Objectives The purpose of our work was to define the complex electrophysiological characteristics seen in second- (2°) and third-degree (3°) atrioventricular block (AVB) and to longitudinally follow the development of atrial and ventricular heart rate and rhythm patterns with a goal of identifying heart rate and rhythm patterns associated with urgent delivery or neonatal pacing. Background The electrophysiological characteristics of congenital AVB before birth have not been extensively studied, yet the mortality from this disease is substantial. Along with advances in fetal therapies and interventions, a comprehensive natural history specific to the etiology of AVB, as well as the electrophysiological factors influencing outcome, are needed to best select treatment options. Methods Twenty-eight fetuses with AVB were evaluated by fetal magnetocardiography; 21 fetuses were evaluated serially. Results Fetuses with 2° AVB and isolated 3° AVB showed: 1) diverse atrial rhythms and mechanisms of atrioventricular conduction during 2° AVB; 2) junctional ectopic tachycardia and ventricular tachycardia during 3° AVB; 3) reactive ventricular and atrial fetal heart rate (FHR) tracings at ventricular rates >56 beats/min; and 4) flat ventricular FHR tracings at ventricular rates <56 beats/min despite reactive atrial FHR tracings. In contrast, fetuses with 3° AVB associated with structural cardiac disease exhibited predominantly nonreactive heart rate tracings and simpler rhythms. Conclusions Second-degree AVB, isolated 3° AVB, and 3° AVB associated with structural cardiac disease manifest distinctly different electrophysiological characteristics and outcome. Fetuses with 2° AVB or isolated 3° AVB commonly exhibited complex, changing heart rate and rhythm patterns; all 19 delivered fetuses are alive and healthy. Fetuses with structural cardiac disease and 3° AVB exhibited largely monotonous heart rate and rhythm patterns and poor prognosis. Junctional ectopic

  6. Acute pancreatitis in the paediatric age group: a personal experience.

    PubMed

    Cosentini, A; Stranieri, G; Capillo, S; Notarangelo, L; Madonna, L; Iannini, S; Ferro, V; Defilippo, V; Defilippo, R G; Rubino, R

    2005-01-01

    Although relatively rare, acute pancreatitis is the most common disease complex involving the pancreas in the paediatric age group. The etiology of the disease is often unknown, and Italian epidemiological data on the paediatric population and, in particular, on the etiology of the disease are not available (except for studies of prevalence). Within the field of the most frequently encountered pancreatitis in the age range of our interest (i.e. 0-18 years), not only the commonly observed forms whose etiopathogenesis is ascribable to cholelithiasis must be mentioned but also those forms due to proteic-caloric malnutrition that are becoming increasingly common. The presenting clinical symptoms and signs may not be typical and the laboratory tests may not always be sensitive enough. In such age range chronic recurrent pancreatitis plays a very important epidemiologic role. Approximately 40% of children and teenagers admitted to the hospital with a diagnosis of pancreatitis report a previous episode of the disease. Irreversible changes in pancreatic parenchyma develop in those patients in whom the disease progresses, leading to pancreatic insufficiency. Such a morbid condition (chronic pancreatitis) is more often observed in adolescents, in whom the disease manifests itself with a vague repetitive dyspeptic symptomatology, after alternating remissions and recrudescences, not always clinically evident. In children, the clinical picture most commonly encountered is represented by recurrent abdominal pains, in view of the fact that the patients are frequently affected by thalassaemia. The pseudocystic evolution of the disease is the most common organic damage resulting from the chronic progression of the pancreatic impairment. A few differences have been found with respect to severity, etiology, and mortality of pancreatitis in the paediatric age group as compared with older age groups. Both the general practitioner with a paediatric practice and the paediatrician

  7. Advanced Electrophysiologic Mapping Systems

    PubMed Central

    2006-01-01

    was conducted to identify studies that compared ablation guided by any of the advanced systems to fluoroscopy-guided ablation of tachycardia. English-language studies with sample sizes greater than or equal to 20 that were published between 2000 and 2005 were included. Observational studies on safety of advanced mapping systems and fluoroscopy were also included. Outcomes of interest were acute success, defined as termination of arrhythmia immediately following ablation; long-term success, defined as being arrhythmia free at follow-up; total procedure time; fluoroscopy time; radiation dose; number of radiofrequency pulses; complications; cost; and the cost-effectiveness ratio. Quality of the individual studies was assessed using established criteria. Quality of the overall evidence was determined by applying the GRADE evaluation system. (3) Qualitative synthesis of the data was performed. Quantitative analysis using Revman 4.2 was performed when appropriate. Quality of the Studies Thirty-four studies met the inclusion criteria. These comprised 18 studies on CARTO (4 randomized controlled trials [RCTs] and 14 non-RCTs), 3 RCTs on EnSite NavX, 4 studies on LocaLisa Navigational System (1 RCT and 3 non-RCTs), 2 studies on EnSite and CARTO, 1 on Polar Constellation basket catheter, and 7 studies on radiation safety. The quality of the studies ranged from moderate to low. Most of the studies had small sample sizes with selection bias, and there was no blinding of patients or care providers in any of the studies. Duration of follow-up ranged from 6 weeks to 29 months, with most having at least 6 months of follow-up. There was heterogeneity with respect to the approach to ablation, definition of success, and drug management before and after the ablation procedure. Summary of Findings Evidence is based on a small number of small RCTS and non-RCTS with methodological flaws. Advanced nonfluoroscopy mapping/navigation systems provided real time 3-dimensional images with

  8. Acute respiratory disease in Spain: seven years of experience.

    PubMed

    Tellez, A; Perez-Breña, P; Fernandez-Patiño, M V; León, P; Anda, P; Nájera, R

    1990-01-01

    The clinical and epidemiologic features of viral and nonviral pathogens involved in acute respiratory diseases are described in the context of cases of infection (especially atypical pneumonia and bronchiolitis) studied at the Centro Nacional de Microbiología, Virología e Immunología Sanitarias in Madrid during a 7-year period (1979-1986). These etiologies were demonstrated in 1,637 (36.2%) of 4,521 cases. Among viruses, respiratory syncytial virus most frequently infected children; influenza virus showed the same pattern of circulation as in other European countries. Of nonviral agents, Mycoplasma pneumoniae and C. burnetii were most often involved in lower respiratory tract infections, with a variable predominance in patients of different ages. A high proportion of cases of M. pneumoniae infection occurred in infants and children aged less than 1 year, and most of these cases occurred during spring and summer. The majority of Q fever cases, including those observed in two outbreaks, occurred in the northern region.

  9. Management of Acute Osteomyelitis: A Ten-Year Experience

    PubMed Central

    Helm, Caitlin; Huschart, Emily; Kaul, Rajat; Bhumbra, Samina; Blackwood, R. Alexander; Mukundan, Deepa

    2016-01-01

    Osteomyelitis is an infection of the bone; proper management requires prolonged antibiotic treatment. Controversy exists as to when a patient should transition from intravenous to oral antibiotics. However, due to the high bioavailability of some oral antibiotics, optimal time to transition from high to low bioavailability antibiotics is a more valid consideration. Additionally, there are questions surrounding the efficacy of certain antibiotics, specifically trimethoprim-sulfamethoxazole (TMP-SMX), in treating osteomyelitis. After obtaining Institutional Review Board approval from both universities, a retrospective chart review was conducted, utilizing an author-created severity scale, on all patients seen by Pediatric Infectious Diseases at the Universities of Michigan and Toledo with an acute osteomyelitis diagnosis from 2002-2012. There were 133 patients, 106 treated successfully. Success was defined in this study specifically as treatment of <14 weeks without recurrence within 30 days of stopping antibiotics or permanent site disability. Seventeen patients were treated with TMP-SMX at comparable cure rates. Patients with pre-existing bone defects (noted in radiological reports), initial erythrocyte sedimentation rate (ESR)≥70, hematogenous osteomyelitis with soft tissue extension, and skull osteomyelitis were associated with increased failure rate. Switch to low bioavailability antibiotics occurred, on average, at 3.5 weeks; however, switching before then was not associated with decreased cure rate. As prevalence of methicillin-resistant Staphylococcus aureus (MRSA), especially clindamycin-resistant MRSA, increases, TMP-SMX appears to be an acceptable antibiotic. There does not appear to be a minimum length of high bioavailability treatment required for cure. Prior bone defect, extensive infection, ESR≥70, or skull osteomyelitis may be indications for more aggressive management.

  10. Re-visiting the electrophysiology of language.

    PubMed

    Obleser, Jonas

    2015-09-01

    This editorial accompanies a special issue of Brain and Language re-visiting old themes and new leads in the electrophysiology of language. The event-related potential (ERP) as a series of characteristic deflections ("components") over time and their distribution on the scalp has been exploited by speech and language researchers over decades to find support for diverse psycholinguistic models. Fortunately, methodological and statistical advances have allowed human neuroscience to move beyond some of the limitations imposed when looking at the ERP only. Most importantly, we currently witness a refined and refreshed look at "event-related" (in the literal sense) brain activity that relates itself more closely to the actual neurobiology of speech and language processes. It is this imminent change in handling and interpreting electrophysiological data of speech and language experiments that this special issue intends to capture.

  11. [Experiences with acute moderate controlled hemodilution (author's transl)].

    PubMed

    Orlowski, T; Lepert, L; Modrzewski, A

    1976-01-01

    The authors present an own method of hemodilution and experiences gained from 10 patients operated for chronic gastric or duodenal ulcer. The therapuetic results of the method show that it can be applied easely and safely in everyday surgical practice. In the patients treated with it no surgical and anaesthesiological complications could be observed during the operations as well as after them. The autors believe that the method of hemodilution for planned surgical operations will contribute to a more economical use of blood transfusions and to reduction in the occurrence of virus hepatitis.

  12. [Experiences with polychemotherapy of acute leukemias in adults with special reference to the COAP combination].

    PubMed

    Gürtler, R; Raderecht, C

    1975-01-01

    The authors give a report on their experiences with polychemotherapy in 77 acute leukaemias in adults. On this occasion the COAP combination was identified to be well effective and to be an enrichment of therapy because of its low side effects.

  13. Acute Morbidity of Proton Therapy for Prostate Cancer: The Hyogo Ion Beam Medical Center Experience

    SciTech Connect

    Mayahara, Hiroshi Murakami, Masao; Kagawa, Kazufumi; Kawaguchi, Atsuya; Oda, Yasue; Miyawaki, Daisuke; Sasaki, Ryohei; Sugimura, Kazuro; Hishikawa, Yoshio

    2007-10-01

    Purpose: To investigate the incidence and influencing factors of acute genitourinary (GU) and gastrointestinal morbidities in patients with prostate cancer treated with proton therapy. Methods and Materials: A total of 287 patients with histologically proven Stage cT1-T4N0M0 prostate cancer were treated with proton therapy between 2003 and 2004. Of these, 204 (71%) received neoadjuvant androgen suppression therapy. The patients were treated with 190-230-MeV protons using lateral-opposed techniques to a dose of 74 GyE. Dose-volume histogram analyses were performed. The incidence of acute morbidity was evaluated using the National Cancer Institute Common Toxicity Criteria, version 2.0. Clinical factors, including age, clinical target volume, initial prostate-specific antigen level, T stage, presence of diabetes mellitus, and the use of androgen suppression therapy, were investigated to determine whether those affected the incidence of acute GU morbidity. Results: None developed Grade 2 or higher acute gastrointestinal morbidity. In contrast, 111 (39%) and 4 (1%) patients experienced acute Grade 2 and Grade 3 GU morbidities, respectively. However, 87% of the patients were successfully relieved by the administration of a selective {alpha}-1 blocker. Multivariate analysis showed that a larger clinical target volume (p = 0.001) and the use of androgen suppression therapy (p = 0.017) were significant factors for the prediction of acute Grade 2-3 GU morbidity. Conclusion: In our experience with proton therapy, a low incidence of acute gastrointestinal morbidity was observed. In contrast, the incidence of acute GU morbidity was similar to that in other reports of photon radiotherapy. Additional follow-up is warranted to elucidate the long-term safety and efficacy of proton therapy for prostate cancer.

  14. Symptom Recognition and Healthcare Experiences of Young Women with Acute Myocardial Infarction

    PubMed Central

    Lichtman, Judith H.; Leifheit-Limson, Erica C.; Watanabe, Emi; Allen, Norrina B.; Garavalia, Brian; Garavalia, Linda S.; Spertus, John A.; Krumholz, Harlan M.; Curry, Leslie A.

    2016-01-01

    Background Prompt recognition of acute myocardial infarction (AMI) symptoms and timely care-seeking behavior are critical to optimize acute medical therapies. Relatively little is known about the symptom presentation and care-seeking experiences of women aged ≤55 years with AMI, a group shown to have increased mortality risk as compared with similarly aged men. Understanding symptom recognition and experiences engaging the healthcare system may provide opportunities to reduce delays and improve acute care for this population. Methods and Results We conducted a qualitative study using in-depth interviews with 30 women (aged 30-55 years) hospitalized with AMI to explore their experiences with prodromal symptoms and their decision-making process to seek medical care. Five themes characterized their experiences: 1) prodromal symptoms varied substantially in both nature and duration; 2) they inaccurately assessed personal risk of heart disease and commonly attributed symptoms to non-cardiac causes; 3) competing and conflicting priorities influenced decisions about seeking acute care; 4) the healthcare system was not consistently responsive to them, resulting in delays in workup and diagnosis; and 5) they did not routinely access primary care, including preventive care for heart disease. Conclusions Participants did not accurately assess their cardiovascular risk, reported poor preventive health behaviors, and delayed seeking care for symptoms, suggesting that differences in both prevention and acute care may be contributing to young women's elevated AMI mortality relative to men. Identifying factors that promote better cardiovascular knowledge, improved preventive health care, and prompt care-seeking behaviors represent important targets for this population. PMID:25714826

  15. Depth Attenuation Degree Based Visualization for Cardiac Ischemic Electrophysiological Feature Exploration

    PubMed Central

    Liu, Lei; Zuo, Wangmeng; Zhang, Henggui

    2016-01-01

    Although heart researches and acquirement of clinical and experimental data are progressively open to public use, cardiac biophysical functions are still not well understood. Due to the complex and fine structures of the heart, cardiac electrophysiological features of interest may be occluded when there is a necessity to demonstrate cardiac electrophysiological behaviors. To investigate cardiac abnormal electrophysiological features under the pathological condition, in this paper, we implement a human cardiac ischemic model and acquire the electrophysiological data of excitation propagation. A visualization framework is then proposed which integrates a novel depth weighted optic attenuation model into the pathological electrophysiological model. The hidden feature of interest in pathological tissue can be revealed from sophisticated overlapping biophysical information. Experiment results verify the effectiveness of the proposed method for intuitively exploring and inspecting cardiac electrophysiological activities, which is fundamental in analyzing and explaining biophysical mechanisms of cardiac functions for doctors and medical staff. PMID:28004002

  16. Comparison of Early and Delayed Laparoscopic Cholecystectomy for Acute Cholecystitis: Experience from A Single Center

    PubMed Central

    Gul, Rouf; Dar, Rayees Ahmad; Sheikh, Riyaz Ahmad; Salroo, Nazir Ahmad; Matoo, Adnan Rashid; Wani, Sabiya Hamid

    2013-01-01

    Background: Cholecystectomy for symptomatic gallstones is mainly performed after the acute cholecystitis episode settles because of the fear of higher morbidity and conversion from laparoscopic cholecystectomy to open cholecystectomy during acute cholecystitis. Aims: To evaluate the safety and feasibility of laparoscopic cholecystectomy for acute cholecystitis and to compare the results with delayed cholecystectomy. Materials and Methods: This was a prospective and randomized study. For patients assigned to early group, laparoscopic cholecystectomy was performed as soon as possible within 72 hours of admission. Patients in the delayed group were treated conservatively and discharged as soon as the acute attack subsided. They were subsequently readmitted for elective laparoscopic cholecystectomy 6-12 weeks later. Results: There was no significant difference in the conversion rates, postoperative analgesia requirements, or postoperative complications. However, the early group had significantly more blood loss, more operating time, and shorter hospital stay. Conclusion: Early laparoscopic cholecystectomy within 72 hours of onset of symptoms has both medical as well as socioeconomic benefits and should be the preferred approach for patients managed by surgeons with adequate experience in laparoscopic cholecystectomy. PMID:24020050

  17. [Romantic origins of electrophysiology].

    PubMed

    Isler, H

    1992-12-01

    Research on static electricity and its effects on the human body date back to the invention of the electrizing or Wimshurst machine and the Leyden jar of 1743 and 1746. Such experiments often served as social pastimes, but they yielded many publications on medical aspects of static electricity. Attempts to explain the 'life force' of the vitalists and the old concept of the active principle of the nervous system, the 'spiritus animales', as electrical phenomena were unsuccessful because of the skeptic comments of leading experimental scientists such as Albrecht von Haller. When Mesmer reinvented 'animal magnetism' in 1776 as a fashionable term for treatment by suggestion, he appropriated theoretical, technical and social methods from the established ways of the experiments on static electricity. Therefore, the scientific character of Luigi Galvani's investigations was already compromised by his term 'animal electricity' when he published his famous 'Commentarius' in 1781. Volta in Pavia turned against Galvani, proving that galvanic currents are produced by metals alone, and rejecting 'animal electricity'. Volta's doctrine prevailed over Galvani's school after Volta's breakthrough with his pile, or battery, until Galvani's ideas were rehabilitated by Nobili, who in 1828 measured the 'frog current' with his galvanometer. This led to a flurry of bizarre experiments on rows of half-dismembered animals and severed parts of human cadavers. Johannes Müller in Berlin, who, with his students, established new principles of biology and neurology, asked Du Bois-Reymond to study these experiments. Du Bois-Reymond found that measurements of muscle currents in intact animals were more useful, and he compared them with his own observations on electric fishes.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Acute Exercise in Vietnam Veterans is Associated with Positive Subjective Experiences.

    PubMed

    Sealey, Rebecca M

    A person's subjective experience to their first exercise session is likely to influence their long-term adherence to regular exercise. The aim of the current pilot study therefore is to quantify the subjective exercise experience of previously sedentary Vietnam War Veterans undertaking an initial bout of one of three different exercise interventions. Thirty-two Vietnam Veterans presenting with one or more chronic diseases/conditions participated in one of three acute exercise bouts: 1) lower-body vibration, upper-body resistance and stretching (WBVT); 2) lower-body vibration, upper-body resistance, aerobic exercise and stretching (WBVT+CV); and 3) full-body resistance, aerobic exercise and stretching (R+CV). Pre and post acute exercise measures of positive well being, psychological distress and fatigue were assessed with the Subjective Exercise Experiences Scale (SEES). A 3(conditions) × 2(time) repeated measures ANOVA with post-hoc Tukey HSD was used to identify any significant differences in SEES between exercise groups and pre and post-exercise. All interventions increased positive well being, with WBVT and R+CV reporting improvements across all areas of the SEES. The WBVT+CV group reported slightly increased psychological distress and the greatest increase in fatigue. An acute bout of exercise increases positive well-being in previously sedentary War Veterans however a longer-duration exercise bout containing multiple exercise modes may be too demanding for this population. Exercise professionals should consider commencing with a simple program to minimise psychological distress and fatigue as this may negatively impact on exercise adherence.

  19. Patients with acute chest pain - experiences of emergency calls and pre-hospital care.

    PubMed

    Forslund, Kerstin; Kihlgren, Mona; Ostman, Ingela; Sørlie, Venke

    2005-01-01

    Acute chest pain is a common reason why people call an emergency medical dispatch (EMD) centre. We examined how patients with acute chest pain experience the emergency call and their pre-hospital care. A qualitative design was used with a phenomenological-hermeneutic approach. Thirteen patients were interviewed, three women and 10 men. The patients were grateful that their lives had been saved and in general were satisfied with their pre-hospital contact. Sometimes they felt that it took too long for the emergency operators to answer and to understand the urgency. They were in a life-threatening situation and their feeling of vulnerability and dependency was great. Time seemed to stand still while they were waiting for help during their traumatic experience. The situation was fraught with pain, fear and an experience of loneliness. A sense of individualized care is important to strengthen trust and confidence between the patient and the pre-hospital personnel. Patients were aware of what number to call to reach the EMD centre, but were uncertain about when to call. More lives can be saved if people do not hesitate to call for help.

  20. Talking therapy groups on acute psychiatric wards: patients' experience of two structured group formats.

    PubMed

    Radcliffe, Jonathan; Bird, Laura

    2016-08-01

    Aims and method We report the results of a clinical audit of patients' reactions to two types of talking therapy groups facilitated by assistant psychologists and psychology graduates on three acute wards. Patients' experiences of problem-solving and interpersonal group formats were explored via focus groups and structured interviews with 29 group participants. Results Both group formats generated high satisfaction ratings, with benefits related mostly to generic factors. Clinical implications Adequately trained and supported assistant psychologists and psychology graduates can provide supportive talking groups that patients find helpful.

  1. Investigation of the degree of organisational influence on patient experience scores in acute medical admission units in all acute hospitals in England using multilevel hierarchical regression modelling

    PubMed Central

    Sullivan, Paul

    2017-01-01

    Objectives Previous studies found that hospital and specialty have limited influence on patient experience scores, and patient level factors are more important. This could be due to heterogeneity of experience delivery across subunits within organisations. We aimed to determine whether organisation level factors have greater impact if scores for the same subspecialty microsystem are analysed in each hospital. Setting Acute medical admission units in all NHS Acute Trusts in England. Participants We analysed patient experience data from the English Adult Inpatient Survey which is administered to 850 patients annually in each acute NHS Trusts in England. We selected all 8753 patients who returned the survey and who were emergency medical admissions and stayed in their admission unit for 1–2 nights, so as to isolate the experience delivered during the acute admission process. Primary and secondary outcome measures We used multilevel logistic regression to determine the apportioned influence of host organisation and of organisation level factors (size and teaching status), and patient level factors (demographics, presence of long-term conditions and disabilities). We selected ‘being treated with respect and dignity’ and ‘pain control’ as primary outcome parameters. Other Picker Domain question scores were analysed as secondary parameters. Results The proportion of overall variance attributable at organisational level was small; 0.5% (NS) for respect and dignity, 0.4% (NS) for pain control. Long-standing conditions and consequent disabilities were associated with low scores. Other item scores also showed that most influence was from patient level factors. Conclusions When a single microsystem, the acute medical admission process, is isolated, variance in experience scores is mainly explainable by patient level factors with limited organisational level influence. This has implications for the use of generic patient experience surveys for comparison between

  2. Survey study of challenging experiences after ingesting psilocybin mushrooms: Acute and enduring positive and negative consequences.

    PubMed

    Carbonaro, Theresa M; Bradstreet, Matthew P; Barrett, Frederick S; MacLean, Katherine A; Jesse, Robert; Johnson, Matthew W; Griffiths, Roland R

    2016-12-01

    Acute and enduring adverse effects of psilocybin have been reported anecdotally, but have not been well characterized. For this study, 1993 individuals (mean age 30 yrs; 78% male) completed an online survey about their single most psychologically difficult or challenging experience (worst "bad trip") after consuming psilocybin mushrooms. Thirty-nine percent rated it among the top five most challenging experiences of his/her lifetime. Eleven percent put self or others at risk of physical harm; factors increasing the likelihood of risk included estimated dose, duration and difficulty of the experience, and absence of physical comfort and social support. Of the respondents, 2.6% behaved in a physically aggressive or violent manner and 2.7% received medical help. Of those whose experience occurred >1 year before, 7.6% sought treatment for enduring psychological symptoms. Three cases appeared associated with onset of enduring psychotic symptoms and three cases with attempted suicide. Multiple regression analysis showed degree of difficulty was positively associated, and duration was negatively associated, with enduring increases in well-being. Difficulty of experience was positively associated with dose. Despite difficulties, 84% endorsed benefiting from the experience. The incidence of risky behavior or enduring psychological distress is extremely low when psilocybin is given in laboratory studies to screened, prepared, and supported participants.

  3. Olfaction in dragonflies: electrophysiological evidence.

    PubMed

    Rebora, Manuela; Salerno, Gianandrea; Piersanti, Silvana; Dell'otto, Alessandro; Gaino, Elda

    2012-02-01

    The problem of olfaction in Paleoptera (Odonata, Ephemeroptera) cannot be considered fully elucidated until now. These insects have been traditionally considered anosmic, because their brain lacks glomerular antennal lobes, typically involved in Neoptera odor perception. In order to understand if the presumed coeloconic olfactory receptors described on the antennal flagellum of adult Odonata are really functioning, we performed an electrophysiological investigation with electroantennogram (EAG) and single cell recordings (SCR), using Libellula depressa L. (Odonata, Libellulidae) as a model species. Odors representing different chemical classes such as (Z)-3-hexenyl acetate (acetate ester), (E)-2-hexenal, octanal (aldehydes), (Z)-3-hexen-1-ol (alcohol), propionic acid, butyric acid (carboxylic acids), and 1,4-diaminobutane (amine) were tested. Most of the tested chemicals elicited depolarizing EAG responses in both male and female antennae; SCR show unambiguously for the first time the presence of olfactory neurons in the antennae of L. depressa and strongly support the olfactory function of the coeloconic sensilla located on the antennal flagellum of this species. Electrophysiological activity may not necessarily indicate behavioral activity, and the biological role of olfactory responses in Odonata must be determined in behavioral bioassays. This study represents a starting point for further behavioral, electrophysiological, neuroanatomical and molecular investigation on Odonata olfaction, a research field particularly interesting owing to the basal position of Paleoptera, also for tracing evolutionary trends in insect olfaction.

  4. Experiences of parenting a child with medical complexity in need of acute hospital care.

    PubMed

    Hagvall, Monica; Ehnfors, Margareta; Anderzén-Carlsson, Agneta

    2016-03-01

    Parents of children with medical complexity have described being responsible for providing advanced care for the child. When the child is acutely ill, they must rely on the health-care services during short or long periods of hospitalization. The purpose of this study was to describe parental experiences of caring for their child with medical complexity during hospitalization for acute deterioration, specifically focussing on parental needs and their experiences of the attitudes of staff. Data were gathered through individual interviews and analyzed using qualitative content analysis. The care period can be interpreted as a balancing act between acting as a caregiver and being in need of care. The parents needed skilled staff who could relieve them of medical responsibility, but they wanted to be involved in the care and in the decisions taken. They needed support, including relief, in order to meet their own needs and to be able to take care of their children. It was important that the child was treated with respect in order for the parent to trust the staff. An approach where staff view parents and children as a single unit, as recipients of care, would probably make the situation easier for these parents and children.

  5. Neurofeedback therapy in patients with acute and chronic pain syndromes--literature review and own experience.

    PubMed

    Kubik, Alicja; Biedroń, Agnieszka

    2013-01-01

    Pain management is based mainly on pharmacotherapy which has many limitations. Non-pharmacological techniques, like neurofeedback (EEG-biofeedback) are alternative methods of pain treatment. Data from literature confirm high efficacy of neurofeedback in pain syndromes treatment, chronic and acute as well. Neurofeedback plays an important role in management of post stroke, post traumatic headaches and in primary headaches like tension type headaches or migraine. Literature review and own experience indicate importance of number and frequency of performed neurofeedback trainings on treatment effectiveness. Satisfactory results have already been observed after 30 trainings however usually 40-60 training have to be performed. Effectiveness of such therapy in pain syndromes is usually good or less often acceptable (50% reduction of headaches). Children with tension type headaches (differently than adults) need reminder therapy every 6-12 months, otherwise recurrence of headaches is observed. Based on our own experience neurofeedback therapy seems to play role in neuropathic pain and cancer pain management.

  6. Neuromuscular Functions on Experimental Acute Methanol Intoxication

    PubMed Central

    Moral, Ali Reşat; Çankayalı, İlkin; Sergin, Demet; Boyacılar, Özden

    2015-01-01

    Objective The incidence of accidental or suicidal ingestion of methyl alcohol is high and methyl alcohol intoxication has high mortality. Methyl alcohol intoxication causes severe neurological sequelae and appears to be a significant problem. Methyl alcohol causes acute metabolic acidosis, optic neuropathy leading to permanent blindness, respiratory failure, circulatory failure and death. It is metabolised in the liver, and its metabolite formic acid has direct toxic effects, causing oxidative stress, mitochondrial damage and increased lipid peroxidation associated with the mechanism of neurotoxicity. Methanol is known to cause acute toxicity of the central nervous system; however, the effects on peripheral neuromuscular transmission are unknown. In our study, we aimed to investigate the electrophysiological effects of experimentally induced acute methanol intoxication on neuromuscular transmission in the early period (first 24 h). Methods After approval by the Animal Experiment Ethics Committee of Ege University, the study was carried out on 10 Wistar rats, each weighing about 200 g. During electrophysiological recordings and orogastric tube insertion, the rats were anaesthetised using intra-peritoneal (IP) injection of ketamine 100 mg kg−1 and IP injection of xylazine 10 mg kg−1. The rats were given 3 g kg−1 methyl alcohol by the orogastric tube. Electrophysiological measurements from the gastrocnemius muscle were compared with baseline. Results Latency measurements before and 24 h after methanol injection were 0.81±0.11 ms and 0.76±0.12 ms, respectively. CMAP amplitude measurements before and 24 h after methanol injection were 9.85±0.98 mV and 9.99±0.40 mV, respectively. CMAP duration measurements before and 24 h after methanol injection were 9.86±0.03 ms and 9.86±0.045 ms, respectively. Conclusion It was concluded that experimental methanol intoxication in the acute phase (first 24 h) did not affect neuromuscular function. PMID:27366524

  7. Reproductive Experience Alters Neural and Behavioural Responses to Acute Oestrogen Receptor α Activation

    PubMed Central

    Byrnes, E. M.; Casey, K.; Carini, L. M.; Bridges, R. S.

    2014-01-01

    Reproductive experience (i.e. parturition and lactation) leads to persistent alterations in anxietylike behaviour that are influenced by the oestrous cycle. We recently found that repeated administration of the selective oestrogen receptors (ER)α agonist propyl-pyrazole triol (PPT) results in anxiolytic-like behaviours on the elevated plus maze (EPM) in primiparous (but not nulliparous) female rats. The present study examined the effects of the acute administration of PPT on EPM behaviour in primiparous and aged-matched, nulliparous female rats. In addition, corticosterone secretion, corticotrophin-releasing hormone (CRH) gene expression and expression of the immediate early gene product Fos in the paraventricular nucleus (PVN) and amygdala were measured either after EPM testing or in home cage controls. Acute PPT administration significantly modified EPM behaviour as a function of reproductive experience, with nulliparous females tending toward increased anxiety-like behaviours and primiparous females tending toward decreased anxiety-like behaviours. In home cage controls, PPT increased corticosterone secretion in all females; however, both vehicle- and PPT-treated, primiparous females had reduced corticosterone levels compared to their nulliparous counterparts. Significant effects of PPT on CRH mRNA within the PVN were observed after the administration of PPT but only in primiparous females tested on the EPM. PPT also increased Fos expression within the PVN of EPM-exposed females; however, both vehicle- and PPT-treated primiparous females had reduced Fos expression compared to nulliparous females. In the amygdala, PPT increased Fos immunore-activity in the central but not the medial or basolateral amygdala, although these effects were only observed in home cage females. Additionally, both vehicle- and PPT-treated home cage, primiparous females had increased Fos in the central nucleus of the amygdala compared to nullip-arous controls. Overall, these data

  8. Automatic Parameterization Strategy for Cardiac Electrophysiology Simulations.

    PubMed

    Costa, Caroline Mendonca; Hoetzl, Elena; Rocha, Bernardo Martins; Prassl, Anton J; Plank, Gernot

    2013-10-01

    Driven by recent advances in medical imaging, image segmentation and numerical techniques, computer models of ventricular electrophysiology account for increasingly finer levels of anatomical and biophysical detail. However, considering the large number of model parameters involved parameterization poses a major challenge. A minimum requirement in combined experimental and modeling studies is to achieve good agreement in activation and repolarization sequences between model and experiment or patient data. In this study, we propose basic techniques which aid in determining bidomain parameters to match activation sequences. An iterative parameterization algorithm is implemented which determines appropriate bulk conductivities which yield prescribed velocities. In addition, a method is proposed for splitting the computed bulk conductivities into individual bidomain conductivities by prescribing anisotropy ratios.

  9. The electrophysiological signature of deliberate rule violations.

    PubMed

    Pfister, Roland; Wirth, Robert; Schwarz, Katharina A; Foerster, Anna; Steinhauser, Marco; Kunde, Wilfried

    2016-12-01

    Humans follow rules by default, and violating even simple rules induces cognitive conflict for the rule breaker. Previous studies revealed this conflict in various behavioral measures, including response times and movement trajectories. Based on these experiments, we investigated the electrophysiological signature of deliberately violating a simple stimulus-response mapping rule. Such rule violations were characterized by a delayed and attenuated P300 component when evaluating a rule-relevant stimulus, most likely reflecting increased response complexity. This parietal attenuation was followed by a frontal positivity for rule violations relative to correct response trials. Together, these results reinforce previous findings on the need to inhibit automatic S-R translation when committing a rule violation, and they point toward additional factors involved in rule violation. Candidate processes such as negative emotional responses and increased monitoring should be targeted by future investigations.

  10. Acute symptomatic Meckel diverticulum management. Our experience on seven consecutive cases.

    PubMed

    Robustelli, Umberto; Manguso, Francesco; Armellino, Mariano Fortunato; Mannelli, Maria Pia; Massa, Maria Rosaria; Forner, Anna Lucia; Bellotti, Roberto; Ambrosino, Francesco; Severino, Beatrice Ulloa

    2014-01-01

    Meckel's diverticulum (MD ) is the most common congenital anomaly of the gastrointestinal tract. We revalued clinical records of patients discharged from Unit of Urgent and General Surgery of Highly Specialized Hospital "A.O.R.N. Antonio Cardarelli" of Naples with diagnosis of acute pathology associated to complicated MD from 1(st) January 2011 to 30(th) November 2012. Seven consecutive cases have been chosen: five males (71,4%) and two females (28,6%). The age ranges over from 13 to 50 years with a 28 years average. Four of them were submitted to emergency surgical intervention for hemorrhage from gastro-enteric tract (57%), two for bowel obstruction (29%) and one for acute appendicitis (14%). In all cases sample was send to histological examination. Two samples showed normal epithelial mucosa. Four of them showed ectopic mucosa inside the diverticulum: three gastric and one pancreatic ectopic mucosa focal areas. The last case showed normal epithelial cells but with ulcerated and hemorrhagic areas. Four samples of patients with hemorrhage from gastroenteric tract showed at histological examination: a case of normal mucosa, a case of gastric mucosa areas, one of pancreatic ectopic tissue and the last with normal mucosa but ulcerated and with bleeding areas.In our experience we never speculated that acute symptomatology depended on complicated MD and diagnosis was always done during laparotomy. We think that MD removal is always the correct choice, so that future complications such as neoplasm can be avoided. MD simple resection by Stapler at the base of diverticulum is the correct choice.

  11. Psychiatric nurse practitioners' experiences of working with mental health care users presenting with acute symptoms.

    PubMed

    Ngako, Kgalabi J; Van Rensburg, Elsie S J; Mataboge, Sanah M L

    2012-05-30

    Psychiatric nurse practitioners (PNPs) working with mental health care users presenting with acute symptoms work in a complex environment. This environment is characterised by mental health care users who may present with a history of violence, sexual assault and substance misuse. The objectives of this study were twofold: firstly, to explore and describe the experiences of PNPs working with mental health care users (MHCUs) presenting with acute symptoms; and secondly, to make recommendations for the advanced PNPs to facilitate promotion of the mental health of PNPs with reference to nursing practice, research and education. A qualitative, explorative, descriptive and contextual design was used. The target population was PNPs working with MHCUs presenting with acute symptoms in a public mental health care institution in Gauteng. Data were collected by means of four focus group interviews involving 21 PNPs. The researcher made use of drawings, naïve sketches and field notes for the purpose of data triangulation. Data were analysed in accordance with Tesch's method of open coding. The three themes that emerged were: PNPs experienced working with these MHCUs as entering an unsafe world where care became a burden; they experienced negative emotional reactions and attitudes towards these MHCUs that compromised quality nursing care; and they made a plea for a nurturing environment that would enhance quality nursing care. The PNPs suggest skills and competency development, organisational support, and a need for external resources. Creation of a positive environment and mobilisation of resources as well as the identification and bridging of obstacles are essential in the promotion of the overall wellbeing and mental health of PNPs.

  12. Systemic thrombolysis with recombinant tissue plasminogen activator in acute ischemic stroke: first Croatian experiences.

    PubMed

    Matijević, Vesna; Alvir, Domagoj; Malojčić, Branko; Unušić, Lea; Supe, Svjetlana; Boban, Marina; Bujan-Kovač, Andrea; Habek, Mario; Poljaković, Zdravka

    2010-12-01

    In September 2003, recombinant tissue plasminogen activator (rt-PA) for acute treatment of ischemic stroke was finally approved by the Croatian Ministry of Health. For the next 5 years, only three stroke units in the country implemented this therapy in their routine practice until summer 2008, when neurological wards in most Croatian hospitals started to treat acute stroke patients with systemic thrombolysis. We present a 2-year experience of thrombolytic therapy (2006-2008) in the stroke unit of the University Hospital in Zagreb, Croatian largest hospital, serving nearly one-fifth of the citizens of Croatia. Obtained data (vitals at admission and before administration of rt-PA; NIHSS and MRS scores at admission, 2 h and 7th day after rt-PA treatment, "time to door" and "door to needle" intervals, duration of hospital treatment as well as outcomes and complications of our 66 thrombolysed patients) are presented and discussed. We also present our results regarding benefits of this therapy as well as possible reasons for complications noticed.

  13. Software and hardware infrastructure for research in electrophysiology

    PubMed Central

    Mouček, Roman; Ježek, Petr; Vařeka, Lukáš; Řondík, Tomáš; Brůha, Petr; Papež, Václav; Mautner, Pavel; Novotný, Jiří; Prokop, Tomáš; Štěbeták, Jan

    2014-01-01

    As in other areas of experimental science, operation of electrophysiological laboratory, design and performance of electrophysiological experiments, collection, storage and sharing of experimental data and metadata, analysis and interpretation of these data, and publication of results are time consuming activities. If these activities are well organized and supported by a suitable infrastructure, work efficiency of researchers increases significantly. This article deals with the main concepts, design, and development of software and hardware infrastructure for research in electrophysiology. The described infrastructure has been primarily developed for the needs of neuroinformatics laboratory at the University of West Bohemia, the Czech Republic. However, from the beginning it has been also designed and developed to be open and applicable in laboratories that do similar research. After introducing the laboratory and the whole architectural concept the individual parts of the infrastructure are described. The central element of the software infrastructure is a web-based portal that enables community researchers to store, share, download and search data and metadata from electrophysiological experiments. The data model, domain ontology and usage of semantic web languages and technologies are described. Current data publication policy used in the portal is briefly introduced. The registration of the portal within Neuroscience Information Framework is described. Then the methods used for processing of electrophysiological signals are presented. The specific modifications of these methods introduced by laboratory researches are summarized; the methods are organized into a laboratory workflow. Other parts of the software infrastructure include mobile and offline solutions for data/metadata storing and a hardware stimulator communicating with an EEG amplifier and recording software. PMID:24639646

  14. Personal miniature electrophysiological tape recorder

    NASA Technical Reports Server (NTRS)

    Green, H.

    1981-01-01

    The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.

  15. Personal miniature electrophysiological tape recorder

    NASA Astrophysics Data System (ADS)

    Green, H.

    1981-11-01

    The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.

  16. Diagnosis and treatment of acute urogenital and genitalia tract traumas: 10-year clinical experience

    PubMed Central

    Zou, Qingsong; Fu, Qiang

    2015-01-01

    Objective: To report our 10-year diagnosis and treatment experience of acute urogenital and genitalia tract traumas and outline the management of the traumatic injury. Methods: We reviewed the diagnoses and treatments of 208 cases of acute kidney, ureter, bladder, urethra, or male genitalia injuries in our department between March 2002 and March 2012. The patient data including general information, injury position and mechanism, diagnosis and treatment, the follow-up information was analyzed and summarized. Results: Of 62 patients with renal injury examined by ultrasound and computed tomography (CT) examination, 45 were treated conservatively, 9 with superselective arterial embolization, and 8 with nephrectomy. Intravenous pyelogram (IVP) was conducted in two patients with ureteral injury, one was treated with cystoscopic ureteral catheterization and the other with ureteric reimplantation. Bladder injury (6 patients) confirmed with a waterflood susceptibility test combined with CT scans underwent laparotomy and the bladder suturing was done. Of 92 patients with urethral injury, 6 were treated with a nonoperative approach (indwelling catheter), 18 with urethral realignment, 35 with cystoscopic urethral realignment, 29 with end-to-end anastomotic urethroplasty, and 4 with urethral repairmen. Of the 24 cases with penile injuries, 1 underwent conservative treatment, 8 were treated with debridement and suture ligation, and 15 were managed with suture repair of the penis white membrane. Of the 24 cases with penile injuries, 1 underwent conservative treatment, 8 were treated with debridement and suture ligation, and 15 were managed with suture repair of the penis white membrane. During the follow-up period, 62 patients with renal injury had normal renal function. Neither of the two patients with ureteral injury developed hydronephrosis. Twenty-nine patients with urethral injury suffered from urethral structure. All patients with vesical or genital injury recovered

  17. A highly versatile and easily configurable system for plant electrophysiology.

    PubMed

    Gunsé, Benet; Poschenrieder, Charlotte; Rankl, Simone; Schröeder, Peter; Rodrigo-Moreno, Ana; Barceló, Juan

    2016-01-01

    In this study we present a highly versatile and easily configurable system for measuring plant electrophysiological parameters and ionic flow rates, connected to a computer-controlled highly accurate positioning device. The modular software used allows easy customizable configurations for the measurement of electrophysiological parameters. Both the operational tests and the experiments already performed have been fully successful and rendered a low noise and highly stable signal. Assembly, programming and configuration examples are discussed. The system is a powerful technique that not only gives precise measuring of plant electrophysiological status, but also allows easy development of ad hoc configurations that are not constrained to plant studies. •We developed a highly modular system for electrophysiology measurements that can be used either in organs or cells and performs either steady or dynamic intra- and extracellular measurements that takes advantage of the easiness of visual object-oriented programming.•High precision accuracy in data acquisition under electrical noisy environments that allows it to run even in a laboratory close to electrical equipment that produce electrical noise.•The system makes an improvement of the currently used systems for monitoring and controlling high precision measurements and micromanipulation systems providing an open and customizable environment for multiple experimental needs.

  18. Communicating with culturally and linguistically diverse patients in an acute care setting: nurses' experiences.

    PubMed

    Cioffi, R N Jane

    2003-03-01

    Communication with culturally and linguistically diverse (CLD) patients has been shown to be difficult. This study describes nurses' experiences of communicating with CLD patients in an acute care setting. A purposive sample of registered nurses and certified midwives (n=23) were interviewed. Main findings were: interpreters, bilingual health workers and combinations of different strategies were used to communicate with CLD patients; some nurses showed empathy, respect and a willingness to make an effort in the communication process with others showing an ethnocentric orientation. Main recommendations were: prioritising access to appropriate linguistic services, providing nurses with support from health care workers, e.g., bilingual health care workers who are able to provide more in-depth information, increasing nurses' understanding of legal issues within patient encounters, supporting nurses to translate their awareness of cultural diversity into acceptance of, appreciation for and commitment to CLD patients and their families.

  19. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment

    PubMed Central

    Crisp, Kevin M.; Lin, Hunter; Prosper, Issa

    2016-01-01

    Electrophysiology is a valuable skill for the neuroscientist, but the learning curve for students can be steep. Here we describe a very simple electromyography (EMG) amplifier that can be built from scratch by students with no electronics experience in about 30 minutes, making it ideal for incorporating into a laboratory activity. With few parts and no adjustments except the gain, students can begin physiology experiments quickly while having the satisfaction of having built the equipment themselves. Because the output of the circuit goes to a computer sound card, students can listen to electrophysiological activity as they see it on the computer screen, a feature many of our students greatly appreciated. Various applications are discussed, including dual channel recording, using streaming media platforms with remote lab partners and acquiring data in the field on a smart phone. Our students reported that they enjoyed being able to build a working device and using it to record from their own muscles. PMID:27385921

  20. The subjective experience of acute, experimentally-induced Salvia divinorum inebriation.

    PubMed

    Addy, Peter H; Garcia-Romeu, Albert; Metzger, Matthew; Wade, Jenny

    2015-04-01

    This study examined the overall psychological effects of inebriation facilitated by the naturally-occurring plant hallucinogen Salvia divinorum using a double-blind, randomized, placebo-controlled trial. Thirty healthy individuals self-administered Salvia divinorum via combustion and inhalation in a quiet, comfortable research setting. Experimental sessions, post-session interviews, and 8-week follow-up meetings were audio recorded and transcribed to provide the primary qualitative material analyzed here. Additionally, post-session responses to the Hallucinogen Rating Scale provided a quantitative groundwork for mixed-methods discussion. Qualitative data underwent thematic content analysis, being coded independently by three researchers before being collaboratively integrated to provide the final results. Three main themes and 10 subthemes of acute intoxication emerged, encompassing the qualities of the experience, perceptual alterations, and cognitive-affective shifts. The experience was described as having rapid onset and being intense and unique. Participants reported marked changes in auditory, visual, and interoceptive sensory input; losing normal awareness of themselves and their surroundings; and an assortment of delusional phenomena. Additionally, the abuse potential of Salvia divinorum was examined post hoc. These findings are discussed in light of previous research, and provide an initial framework for greater understanding of the subjective effects of Salvia divinorum, an emerging drug of abuse.

  1. Ammonia Level and Mortality in Acute Liver Failure: A Single-Center Experience.

    PubMed

    Niranjan-Azadi, Ashwini M; Araz, Filiz; Patel, Yuval A; Alachkar, Nada; Alqahtani, Saleh; Cameron, Andrew M; Stevens, Robert D; Gurakar, Ahmet

    2016-08-02

    BACKGROUND Acute liver failure (ALF) is an emergent condition that requires intensive care and manifests in particular by significant elevation in serum ammonia level. Patients with ALF with concomitant renal failure experience a further rise in ammonia levels due to decreased kidney excretion. The aim of this study was to evaluate the relationship between elevated ammonia levels and mortality and to characterize the subgroup of ALF patients who develop acute kidney injury (AKI) and require renal replacement therapy. MATERIAL AND METHODS This was a retrospective study of 36 consecutive patients admitted to Johns Hopkins Hospital's intensive care units from December 2008 to May 2013 who presented with grade III and IV hepatic encephalopathy (HE). Patients who developed AKI and required hemodialysis (HD) were compared to those without AKI. Patients with chronic kidney disease were excluded. RESULTS Sixteen patients developed AKI and underwent HD (HD group). Median ammonia levels in the HD and non-HD groups were not significantly different (p=0.95). In the HD group, 4 patients underwent liver transplantation (LT) and 3 of them survived the hospitalization. Among the 12 HD patients who did not receive LT, 6 (50%) survived. Out of 20 non-HD patients, 3 were transplanted, all of whom survived the hospitalization. Among the 17 non-HD patients who did not receive LT, 14 (82%) survived. Admission ammonia level (>120 µmol/L) was associated with higher mortality rate (OR=7.188 [95% CI 1.3326-38.952], p=0.026) in all patients. CONCLUSIONS Admission ammonia level is predictive of mortality in ALF patients with grade 3-4 HE.

  2. Transfusion Related Acute Lung Injury (TRALI): A Single Institution Experience of 15 Years.

    PubMed

    Kumar, Ramesh; Sedky, Mohammed Jaber; Varghese, Sunny Joseph; Sharawy, Osama Ebrahim

    2016-09-01

    Transfusion related acute Lung injury (TRALI) though a serious blood transfusion reaction with a fatality rate of 5-25 % presents with acute respiratory distress with hypoxaemia and noncardiac pulmonary oedema within 6 h of transfusion. In non fatal cases, it may resolve within 72 h or earlier. Although reported with an incidence of 1:5000, its true occurrence is rather unknown. Pathogenesis is believed to be related to sequestration and adhesion of neutrophils to the pulmonary capillary endothelium and its activation leading to its destruction and leaks. The patient's underlying condition, anti-neutrophil antibody in the transfused donor plasma and certain lipids that accumulate in routinely stores blood and components are important in its aetiopathogenesis. Patient's predisposing conditions include haematological malignancy, major surgery (especially cardiac), trauma and infections. The more commonly incriminated products include fresh frozen plasma (FFP), platelets (whole blood derived and apheresis), whole blood and Packed RBC. Occasional cases involving cryoprecipitate and Intravenous immunoglobulin (IVig) have also been reported. We present a 15 year single institution experience of TRALI, during which we observed 9 cases among 170,871 transfusions, giving an incidence of 1:19,000. We did not encounter cases of haematological malignancy or cardiac surgery in our TRALI patients. Among the blood products, that could be related to TRALI in our patients included solitary cases receiving cryoprecipitate, IVIg, and recombinant Factor VII apart from platelets and FFP. All patients were treated with oxygen support. Six patients required mechanical ventilation. Off label hydrocortisone was given to all patients. There were no cases of fatality among our patients.

  3. Acute O 3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment.

    PubMed

    Darbah, Joseph N T; Jones, Wendy S; Burton, Andrew J; Nagy, John; Kubiske, Mark E

    2011-09-01

    We studied the effect of high ozone (O(3)) concentration (110-490 nmol mol(-1)) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O(3) pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O(3) exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O(3) and/or CO(2) for 12 years, were harvested. Acute O(3) damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O(3) damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O(3) damage as it directly controlled O(3) uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O(3) exposure. Moreover, elevated CO(2) did not ameliorate the adverse effects of acute O(3) dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O(3) levels.

  4. Acute O3 damage on first year coppice sprouts of aspen and maple sprouts in an open-air experiment

    SciTech Connect

    Darbah, J.N.; Nagy, J.; Jones, W. S.; Burton, A. J.; Kubiske, M. E.

    2011-10-01

    We studied the effect of high ozone (O{sub 3}) concentration (110-490 nmol mol{sup -1}) on regenerating aspen (Populus tremuloides) and maple (Acer saccharum) trees at an open-air O{sub 3} pollution experiment near Rhinelander WI USA. This study is the first of its kind to examine the effects of acute O{sub 3} exposure on aspen and maple sprouts after the parent trees, which were grown under elevated O{sub 3} and/or CO{sub 2} for 12 years, were harvested. Acute O{sub 3} damage was not uniform within the crowns of aspen suckers; it was most severe in the mature, fully expanded photosynthesizing leaves. Young expanding leaves showed no visible signs of acute O{sub 3} damage contrary to expectations. Stomatal conductance played a primary role in the severity of acute O{sub 3} damage as it directly controlled O{sub 3} uptake. Maple sprouts, which had lower stomatal conductance, smaller stomatal aperture, higher stomatal density and larger leaf surface area, were tolerant of acute O{sub 3} exposure. Moreover, elevated CO{sub 2} did not ameliorate the adverse effects of acute O{sub 3} dose on aspen and maple sprouts, in contrast to its ability to counteract the effects of long-term chronic exposure to lower O{sub 3} levels.

  5. Acute tubulointerstitial nephritis/drug induced acute kidney injury; an experience from a single center in Pakistan

    PubMed Central

    Naqvi, Rubina; Mubarak, Muhammad; Ahmed, Ejaz; Akhtar, Fazal; Naqvi, Anwar; Rizvi, Adib

    2016-01-01

    Introduction: There is no information in literature specifically on the prevalence and clinicopathological characteristics of acute tubulointerstitial nephritis/drug induced acute kidney injury (AKI) from Pakistan. Objectives: We aim to report a series of cases from patients developing AKI after exposure to some medications or finding of interstitial nephritis on histopathology. Patients and Methods: This is an observational study of patients identified as having AKI after exposure to medications. AKI was defined according to RIFLE criteria and all patients fell from risk to loss category on arrival. On ultrasonography, all patients had normal size non-obstructed kidneys. Renal biopsy findings were consistent with tubule interstitial nephritis. Results: Mean age of patients was 36.41 ± 17.40 years. Among total of 155, 80 were male and 75 female. Regarding drugs, most common was exposure to aminoglycoside in 34 (22%) followed by use of non-steroidal anti-inflammatory analgesics in 28, contrast induced agents in 11. Renal biopsy was performed in 58 patients. In half of these, insulting agent was not known and in rest either multiple medications were ingested or there was denial to substance use or recovery was delayed despite discontinuation of responsible medication. Renal replacement therapy was required on arrival in 119/155 (hemodialysis = 115, peritoneal dialysis = 4) cases. Complete renal recovery was observed in 71%, while 7.7% expired during acute phase, partial renal recovery was seen in 15% and 5% disappeared after first discharge from the hospital. Conclusion: Tubulointerstitial nephritis may occur with many drugs of common use. Early and intensive efforts must be made to consider and then timely correct the injury to the kidney. PMID:27069962

  6. Antivenom Evaluation by Electrophysiological Analysis.

    PubMed

    Restano-Cassulini, Rita; Garcia, Walter; Paniagua-Solís, Jorge F; Possani, Lourival D

    2017-02-23

    Scorpion stings on humans are medically relevant because they may contain toxins that specifically target ion channels. During antivenom production, pharmaceutical companies must use a large number of experimental animals to ensure the antivenom's efficacy according to pharmacopeia methods. Here we present an electrophysiological alternative for the evaluation of horse antivenoms produced against two species of Moroccan scorpions: Buthus mardochei and Androctonus mauretanicus. Human sodium and potassium channels and acetylcholine nicotinic receptors were analyzed by standard patch-clamp techniques. The results showed that the antivenom is capable of reversing ion current disruption caused by the venom application. We propose the use of this in vitro technique for antivenom evaluation as an alternative to using a large number of live animals.

  7. Electrophysiological study of diaphragmatic myoclonus.

    PubMed Central

    Chen, R; Remtulla, H; Bolton, C F

    1995-01-01

    This is the first reported detailed electrophysiological study of diaphragmatic myoclonus. An 86 year old woman had rapid, intermittent epigastric pulsations. Neurological examination and imaging studies of the brain and spinal cord were normal. Needle EMG showed rhythmic contractions of the diaphragm and external intercostal muscles at 4 to 5 Hz. These contractions were often associated with suppression of normal breathing and were capable of maintaining adequate ventilation. Both diaphragms were involved but showed considerable variability in their relative latencies. Automated interference pattern analysis suggested a change in recruitment order, with selective activation of large phrenic motoneurons. The supraspinal mechanisms mediating diaphragmatic myoclonus are different from that of voluntary and involuntary rhythmic breathing, and seem to be unrelated to palatal myoclonus. The generator source is likely related to respiratory centres in the rostral medulla. PMID:7738561

  8. Electrophysiological correlates of change detection.

    PubMed

    Eimer, Martin; Mazza, Veronica

    2005-05-01

    To identify electrophysiological correlates of change detection, event-related brain potentials (ERPs) were recorded while participants monitored displays containing four faces in order to detect a face identity change across successive displays. Successful change detection was mirrored by an N2pc component at posterior electrodes contralateral to the side of a change, suggesting close links between conscious change detection and attention. ERPs on undetected-change trials differed from detected-change and no-change trials. We suggest that short-latency ERP differences between these trial types reflect trial-by-trial fluctuations in advance task preparation, whereas differences in the P3 time range are due to variations in the duration of perceptual and decision-related processing. Overall, these findings demonstrate that ERPs are a useful tool for dissociating processes underlying change blindness and change detection.

  9. Antivenom Evaluation by Electrophysiological Analysis

    PubMed Central

    Restano-Cassulini, Rita; Garcia, Walter; Paniagua-Solís, Jorge F.; Possani, Lourival D.

    2017-01-01

    Scorpion stings on humans are medically relevant because they may contain toxins that specifically target ion channels. During antivenom production, pharmaceutical companies must use a large number of experimental animals to ensure the antivenom’s efficacy according to pharmacopeia methods. Here we present an electrophysiological alternative for the evaluation of horse antivenoms produced against two species of Moroccan scorpions: Buthus mardochei and Androctonus mauretanicus. Human sodium and potassium channels and acetylcholine nicotinic receptors were analyzed by standard patch-clamp techniques. The results showed that the antivenom is capable of reversing ion current disruption caused by the venom application. We propose the use of this in vitro technique for antivenom evaluation as an alternative to using a large number of live animals. PMID:28241514

  10. Evolution of ventricular myocyte electrophysiology.

    PubMed

    Rosati, Barbara; Dong, Min; Cheng, Lan; Liou, Shian-Ren; Yan, Qinghong; Park, Ji Young; Shiang, Elaine; Sanguinetti, Michael; Wang, Hong-Sheng; McKinnon, David

    2008-11-12

    The relative importance of regulatory versus structural evolution for the evolution of different biological systems is a subject of controversy. The primacy of regulatory evolution in the diversification of morphological traits has been promoted by many evolutionary developmental biologists. For physiological traits, however, the role of regulatory evolution has received less attention or has been considered to be relatively unimportant. To address this issue for electrophysiological systems, we examined the importance of regulatory and structural evolution in the evolution of the electrophysiological function of cardiac myocytes in mammals. In particular, two related phenomena were studied: the change in action potential morphology in small mammals and the scaling of action potential duration across mammalian phylogeny. In general, the functional properties of the ion channels involved in ventricular action potential repolarization were found to be relatively invariant. In contrast, there were large changes in the expression levels of multiple ion channel and transporter genes. For the Kv2.1 and Kv4.2 potassium channel genes, which are primary determinants of the action potential morphology in small mammals, the functional properties of the proximal promoter regions were found to vary in concordance with species-dependent differences in mRNA expression, suggesting that evolution of cis-regulatory elements is the primary determinant of this trait. Scaling of action potential duration was found to be a complex phenomenon, involving changes in the expression of a large number of channels and transporters. In this case, it is concluded that regulatory evolution is the predominant mechanism by which the scaling is achieved.

  11. The acute psychobiological impact of the intensive care experience on relatives

    PubMed Central

    Turner-Cobb, J.M.; Smith, P.C.; Ramchandani, P.; Begen, F.M.; Padkin, A.

    2016-01-01

    There is a growing awareness amongst critical care practitioners that the impact of intensive care medicine extends beyond the patient to include the psychological impact on close family members. Several studies have addressed the needs of relatives within the intensive care context but the psychobiological impact of the experience has largely been ignored. Such impact is important in respect to health and well-being of the relative, with potential to influence patient recovery. The current feasibility study aimed to examine the acute psychobiological impact of the intensive care experience on relatives. Using a mixed methods approach, quantitative and qualitative data were collected simultaneously. Six relatives of patients admitted to the intensive care unit (ICU) of a District General Hospital, were assessed within 48 h of admission. Qualitative data were provided from semi-structured interviews analysed using interpretative phenomenological analysis. Quantitative data were collected using a range of standardised self-report questionnaires measuring coping responses, emotion, trauma symptoms and social support, and through sampling of diurnal salivary cortisol as a biomarker of stress. Four themes were identified from interview: the ICU environment, emotional responses, family relationships and support. Questionnaires identified high levels of anxiety, depression and trauma symptoms; the most commonly utilised coping techniques were acceptance, seeking support through advice and information, and substance use. Social support emerged as a key factor with focused inner circle support relating to family and ICU staff. Depressed mood and avoidance were linked to greater mean cortisol levels across the day. Greater social network and coping via self-distraction were related to lower evening cortisol, indicating them as protective factors in the ICU context. The experience of ICU has a psychological and physiological impact on relatives, suggesting the importance of

  12. [Contribution of abdominal sonography in acute appendicitis diagnostics--our experience].

    PubMed

    Smíd, D; Skalický, T; Treska, V

    2009-08-01

    Acute apendicitis is the most frequent case of acute abdomen. During a two year period (2006-2007) it was performed in Department of Surgery of Faculty Hospital in Pilsen 678 appendectomies, 30 days post-operative mortality rate was 0%. Abdomen ultrasonography like helping method to clinic examination was performed in 313 patients, suspect of acute appendicitis was in 191 patients (61%), in remaining patients was normal ultrasound picture.

  13. A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability

    PubMed Central

    Gagnon-Turcotte, Gabriel; Avakh Kisomi, Alireza; Ameli, Reza; Dufresne Camaro, Charles-Olivier; LeChasseur, Yoan; Néron, Jean-Luc; Brule Bareil, Paul; Fortier, Paul; Bories, Cyril; de Koninck, Yves; Gosselin, Benoit

    2015-01-01

    We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm2 at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals. PMID:26371006

  14. A Wireless Optogenetic Headstage with Multichannel Electrophysiological Recording Capability.

    PubMed

    Gagnon-Turcotte, Gabriel; Kisomi, Alireza Avakh; Ameli, Reza; Camaro, Charles-Olivier Dufresne; LeChasseur, Yoan; Néron, Jean-Luc; Bareil, Paul Brule; Fortier, Paul; Bories, Cyril; de Koninck, Yves; Gosselin, Benoit

    2015-09-09

    We present a small and lightweight fully wireless optogenetic headstage capable of optical neural stimulation and electrophysiological recording. The headstage is suitable for conducting experiments with small transgenic rodents, and features two implantable fiber-coupled light-emitting diode (LED) and two electrophysiological recording channels. This system is powered by a small lithium-ion battery and is entirely built using low-cost commercial off-the-shelf components for better flexibility, reduced development time and lower cost. Light stimulation uses customizable stimulation patterns of varying frequency and duty cycle. The optical power that is sourced from the LED is delivered to target light-sensitive neurons using implantable optical fibers, which provide a measured optical power density of 70 mW/mm² at the tip. The headstage is using a novel foldable rigid-flex printed circuit board design, which results into a lightweight and compact device. Recording experiments performed in the cerebral cortex of transgenic ChR2 mice under anesthetized conditions show that the proposed headstage can trigger neuronal activity using optical stimulation, while recording microvolt amplitude electrophysiological signals.

  15. The tarsal taste of honey bees: behavioral and electrophysiological analyses.

    PubMed

    de Brito Sanchez, Maria Gabriela; Lorenzo, Esther; Su, Songkun; Liu, Fanglin; Zhan, Yi; Giurfa, Martin

    2014-01-01

    Taste plays a crucial role in the life of honey bees as their survival depends on the collection and intake of nectar and pollen, and other natural products. Here we studied the tarsal taste of honey bees through a series of behavioral and electrophysiological analyses. We characterized responsiveness to various sweet, salty and bitter tastants delivered to gustatory sensilla of the fore tarsi. Behavioral experiments showed that stimulation of opposite fore tarsi with sucrose and bitter substances or water yielded different outcomes depending on the stimulation sequence. When sucrose was applied first, thereby eliciting proboscis extension, no bitter substance could induce proboscis retraction, thus suggesting that the primacy of sucrose stimulation induced a central excitatory state. When bitter substances or water were applied first, sucrose stimulation could still elicit proboscis extension but to a lower level, thus suggesting central inhibition based on contradictory gustatory input on opposite tarsi. Electrophysiological experiments showed that receptor cells in the gustatory sensilla of the tarsomeres are highly sensitive to saline solutions at low concentrations. No evidence for receptors responding specifically to sucrose or to bitter substances was found in these sensilla. Receptor cells in the gustatory sensilla of the claws are highly sensitive to sucrose. Although bees do not possess dedicated bitter-taste receptors in the tarsi, indirect bitter detection is possible because bitter tastes inhibit sucrose receptor cells of the claws when mixed with sucrose solution. By combining behavioral and electrophysiological approaches, these results provide the first integrative study on tarsal taste detection in the honey bee.

  16. Pants on fire: the electrophysiological signature of telling a lie.

    PubMed

    Pfister, Roland; Foerster, Anna; Kunde, Wilfried

    2014-01-01

    Even though electroencephalography has played a prominent role for lie detection via personally relevant information, the electrophysiological signature of active lying is still elusive. We addressed this signature with two experiments in which participants helped a virtual police officer to locate a knife. Crucially, before this response, they announced whether they would lie or tell the truth about the knife's location. This design allowed us to study the signature of lie-telling in the absence of rare and personally significant oddball stimuli that are typically used for lie detection via electrophysiological markers, especially the P300 component. Our results indicate that active lying attenuated P300 amplitudes as well as N200 amplitudes for such non-oddball stimuli. These results support accounts that stress the high cognitive demand of lie-telling, including the need to suppress the truthful response and to generate a lie.

  17. A wearable chemical–electrophysiological hybrid biosensing system for real-time health and fitness monitoring

    PubMed Central

    Imani, Somayeh; Bandodkar, Amay J.; Mohan, A. M. Vinu; Kumar, Rajan; Yu, Shengfei; Wang, Joseph; Mercier, Patrick P.

    2016-01-01

    Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices. PMID:27212140

  18. A wearable chemical-electrophysiological hybrid biosensing system for real-time health and fitness monitoring.

    PubMed

    Imani, Somayeh; Bandodkar, Amay J; Mohan, A M Vinu; Kumar, Rajan; Yu, Shengfei; Wang, Joseph; Mercier, Patrick P

    2016-05-23

    Flexible, wearable sensing devices can yield important information about the underlying physiology of a human subject for applications in real-time health and fitness monitoring. Despite significant progress in the fabrication of flexible biosensors that naturally comply with the epidermis, most designs measure only a small number of physical or electrophysiological parameters, and neglect the rich chemical information available from biomarkers. Here, we introduce a skin-worn wearable hybrid sensing system that offers simultaneous real-time monitoring of a biochemical (lactate) and an electrophysiological signal (electrocardiogram), for more comprehensive fitness monitoring than from physical or electrophysiological sensors alone. The two sensing modalities, comprising a three-electrode amperometric lactate biosensor and a bipolar electrocardiogram sensor, are co-fabricated on a flexible substrate and mounted on the skin. Human experiments reveal that physiochemistry and electrophysiology can be measured simultaneously with negligible cross-talk, enabling a new class of hybrid sensing devices.

  19. Involvement of activated leukocytes in the regulation of plasma levels of acute phase proteins in microgravity simulation experiments

    NASA Astrophysics Data System (ADS)

    Larina, Olga; Bekker, Anna; Turin-Kuzmin, Alexey

    2016-07-01

    Earth-based studies of microgravity effects showed the induction of the mechanisms of acute phase reaction (APR). APR comprises the transition of stress-sensitive protein kinases of macrophages and other responsive cells into the active state and the phosphorylation of transcription factors which in turn stimulate the production of acute-phase reaction cytokines. Leukocyte activation is accompanied by the acceleration of the formation of oxygen radicals which can serve a functional indice of leukocyte cell state. The series of events at acute phase response result in selective changes in the synthesis of a number of secretory blood proteins (acute phase proteins, APPs) in liver cells thus contributing the recovery of homeostasis state in the organism. Earlier experiment with head-down tilt showed the increase in plasma concentrations of two cytokine mediators of acute phase response, tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) being the outcome of the activation of producer cells, foremost, leukocytes. In experiment with 4-day dry immersion chemiluminescent (ChL) reply of the whole blood samples to a test stimulus were studied along with the measurements of plasma levels of APPs, namely, alpha1-antitrypsin (alpha1-AT), alpha1-acid glycoprotein (alpha1-AGP), alpha2-macroglobulin (alpha2-M), ceruloplasmin (Cer), haptoglobin (Hp), C3-complement component (C3), C-reactive protein (CRP). Eight individuals aged 21.2 ± 3.2 years were the test subjects in the investigation. Protein studies showed a noticeable increase in the mean plasma levels of all APPs measured in experiment thus producing the evidence of the activation of acute phase response mechanisms while individual patterns revealed variability during the immersion period. The overall trends were similar to these in the previous immersion series. The augment in the strength of signal in stimulated light emission tests was higher after 1- and 2-day of immersion exposure than before the

  20. The Experience of Witnessing Patients' Trauma and Suffering among Acute Care Nurses

    ERIC Educational Resources Information Center

    Walsh, Mary E.; Buchanan, Marla J.

    2011-01-01

    A large body of research provides evidence of workplace injuries to those in the nursing profession. Research on workplace stress and burnout among medical professionals is also well known; however, the profession of acute care nursing has not been examined with regards to work-related stress. This qualitative study focused on acute care nurses'…

  1. The antiarrhythmic and cardiac electrophysiological effects of buprenorphine.

    PubMed Central

    Boachie-Ansah, G.; Sitsapesan, R.; Kane, K. A.; Parratt, J. R.

    1989-01-01

    1. The effects of buprenorphine, given intravenously, on the incidence and severity of early acute coronary artery occlusion-induced arrhythmias were examined in anaesthetised rats. The electrophysiological effects of buprenorphine were also examined in sheep Purkinje fibres and rat papillary muscles, superfused in vitro with either a normal or a hypoxic, hyperkalaemic and acidotic physiological salt solution (PSS). 2. In anaesthetised rats subjected to acute coronary artery occlusion, pretreatment with buprenorphine (1 mg kg-1 i.v.) markedly reduced the incidence of ventricular extra-systoles during the initial 30 min post-occlusion period. The incidence of ventricular fibrillation (VF) was also significantly reduced from 56% to 10%. 3. At the antiarrhythmic dose (1 mg kg -1), buprenorphine also attenuated the sudden fall in systemic arterial blood pressure induced by acute coronary artery ligation. 4. In normal sheep Purkinje fibres and rat papillary muscles, buprenorphine (10(-6)-10(-5) M) significantly reduced the action potential height and maximum rate of depolarisation of phase zero (MRD) and prolonged the duration of the action potential. 5. Superfusion of sheep Purkinje fibres and rat papillary muscles with a hypoxic, hyperkalaemic and acidotic PSS resulted in marked reductions in resting membrane potential, upstroke and duration of the action potential. 6. In the presence of the modified compared with normal PSS, buprenorphine reduced the action potential height and MRD of both sheep Purkinje fibres and rat papillary muscles to a greater extent, although its ability to prolong the action potential duration was attenuated. 7. The antiarrhythmic effects of buprenorphine observed in vivo may be explained by its direct cardiac electrophysiological effects.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2758241

  2. Integrated platform and API for electrophysiological data

    PubMed Central

    Sobolev, Andrey; Stoewer, Adrian; Leonhardt, Aljoscha; Rautenberg, Philipp L.; Kellner, Christian J.; Garbers, Christian; Wachtler, Thomas

    2014-01-01

    Recent advancements in technology and methodology have led to growing amounts of increasingly complex neuroscience data recorded from various species, modalities, and levels of study. The rapid data growth has made efficient data access and flexible, machine-readable data annotation a crucial requisite for neuroscientists. Clear and consistent annotation and organization of data is not only an important ingredient for reproducibility of results and re-use of data, but also essential for collaborative research and data sharing. In particular, efficient data management and interoperability requires a unified approach that integrates data and metadata and provides a common way of accessing this information. In this paper we describe GNData, a data management platform for neurophysiological data. GNData provides a storage system based on a data representation that is suitable to organize data and metadata from any electrophysiological experiment, with a functionality exposed via a common application programming interface (API). Data representation and API structure are compatible with existing approaches for data and metadata representation in neurophysiology. The API implementation is based on the Representational State Transfer (REST) pattern, which enables data access integration in software applications and facilitates the development of tools that communicate with the service. Client libraries that interact with the API provide direct data access from computing environments like Matlab or Python, enabling integration of data management into the scientist's experimental or analysis routines. PMID:24795616

  3. An Elective Course in Cardiovascular Electrophysiology for Pharmacy Learners

    PubMed Central

    2016-01-01

    Objective. To implement an integrated, comprehensive, and learner-centered elective course focused at exposing learners to the interpretation of electrocardiograms and highlighting the mechanisms underlining the abnormal electrophysiological events. Design. Learners were presented with foundational information on the mechanisms underlying electrophysiological changes associated with the development of arrhythmias. They then discussed the interpretation of electrocardiogram (ECG) recordings and diagnosis of cardiovascular events. Teaching formats included “chalk-talk” and didactic sessions, case-based exercises providing hands-on evaluation of ECG recordings, and high-fidelity simulation presenting cases of arrhythmias. The course design emphasized critical thinking, learner engagement, and development of problem-solving skills. Learners were assessed by formal assignments, examinations, and in-class quizzes. Assessment. Learner comprehension of the material was assessed using cumulative examinations, in-class quizzes, assignments, and in-class presentations. Learner evaluations showed that the case-based discussions, practice ECGs, review tables, and illustrations enhanced course performance and retention of complex material. Conclusion. The elective course provided in-depth exposure to the mechanisms underlying electrophysiological aberrations resulting in arrhythmias. It gave learners an opportunity to learn the art of ECG interpretation and to apply their knowledge in simulated scenarios. As clinical teams adopt a multidisciplinary team approach to patient care, acquiring these skills enriches learner experiences and allows them to expand their role and professional opportunities as pharmacists. PMID:27899826

  4. Experiences of hand hygiene among acute care nurses: An interpretative phenomenological analysis

    PubMed Central

    Chatfield, Sheryl L; Nolan, Rachael; Crawford, Hannah; Hallam, Jeffrey S

    2016-01-01

    Objective: Occurrences of healthcare-associated infections are associated with substantial direct and indirect costs. Improvement in hand hygiene among acute care nurses has potential to reduce incidence of healthcare-associated infections. Findings from reviews of intervention research have not conclusively identified components that are more or less efficient or effective. Much prior qualitative research has focused on descriptive analysis of policies and practices rather than providing interpretive explorations of how individuals’ perceptions of hygiene might drive practices. Methods: We conducted qualitative interview research with eight nurses in the United States who were employed in various patient-care roles. We analyzed the data using an interpretative phenomenological analysis methodology to explore how nurses described their perceptions of, and experiences with, hygiene. We developed themes that explored individual, workplace, and management influences on perception of hygiene. Results: Developed themes include practical hygiene, risky business, and hygiene on trial; the latter theme described the conflict between how nurses perceived their own hygiene practices and how they felt hospital management perceived these practices. Other findings included that participants distinguished between policy-mandated use of sanitizer and a personal sense of cleanliness; the latter was more likely to be associated with scrubbing or removal of contaminants than with use of protectants. Conclusion: While participants asserted support for facility hand hygiene policies, their behavior in certain instances might be mediated by broadly defined emergent situations and a belief that it is not currently possible to establish a causal link between an healthcare-associated infections and a specific individual or occurrence. Researchers and infection prevention practitioners might consider soliciting greater input from nurses in planning hand hygiene improvement interventions

  5. [Influence of iron nanoparticles on cardiac performance and hemodynamics in rabbits after intravenous administration in acute experiment].

    PubMed

    Doroshenko, A M

    2014-01-01

    Iron nanoparticles are possessed by high potential in the creation of effective and safe antianemic drugs due to the enhanced biological activity of metal nanoparticles. As a step of intravenous dosage form development the study of short-term effects of iron nanoparticles on the cardiovascular system is important. Dose-dependent changes of systemic hemodynamics' parameters were established in acute experiment on rabbits after several intravenous injections of zero-valent iron nanoparticles solution.

  6. Acute schistosomiasis in travelers: 14 years' experience at the Hospital for Tropical Diseases, London.

    PubMed

    Logan, Sarah; Armstrong, Margaret; Moore, Elinor; Nebbia, Gaia; Jarvis, Joseph; Suvari, Muhiddin; Bligh, John; Chiodini, Peter L; Brown, Michael; Doherty, Tom

    2013-06-01

    We report 79 cases of acute schistosomiasis. Most of these cases were young, male travelers who acquired their infection in Lake Malawi. Twelve had a normal eosinophil count at presentation and 11 had negative serology, although two had neither eosinophilia nor positive serology when first seen. Acute schistosomiasis should be considered in any febrile traveler with a history of fresh water exposure in an endemic area once malaria has been excluded.

  7. "It's the people that make the environment good or bad": the patient's experience of the acute care hospital environment.

    PubMed

    Shattell, Mona; Hogan, Beverly; Thomas, Sandra P

    2005-01-01

    A review of contemporary nursing research reveals a tendency to focus on select aspects of the hospital environment such as noise, light, and music. Although studies such as these shed light on discrete aspects of the hospital environment, this body of literature contributes little to an understanding of the entirety of that world as the patient in the sickbed experiences it. The purpose of the study detailed in this article was to describe the patient's experience of the acute care hospital environment. Nondirective, in-depth phenomenological interviews were conducted, then transcribed verbatim, and analyzed for themes. Against the backdrop of "I lived and that's all that matters," there were 3 predominant themes in patients' experience of the acute care environment: (1) disconnection/connection, (2) fear/less fear, and (3) confinement/freedom. In this environment, human-to-human contact increased security and power in an environment that was described as sterile, disorienting, and untrustworthy. Acute and critical care nurses and other caregivers can use the findings to create less noxious hospital environments.

  8. Historical perspectives on interventional electrophysiology.

    PubMed

    Lüderitz, Berndt

    2003-10-01

    The history of interventional electrophysiology is long and fascinating. In the beginning, there is not simply the anatomy and physiology of the heart, but also analysis of the pulse, which indicates the activity of the heart. The analysis of the (peripheral) pulse as a mechanical expression of heart activity goes back several millennia. In China, in 280 B.C., Wang Chu Ho wrote ten books about the pulse. The Greeks called the pulse "sphygmos", and the sphygmology thus deals with a theory of this natural occurrence. In Roman times, Galen interpreted the various types of pulse according to the widespread presumption of the time, that each organ in every disease has its own form of pulse. The basic tool for arrhythmia diagnosis became the electrocardiography introduced by Willem Einthoven who obtained the first human electrogram 1902 in Leiden, The Netherlands. The growing clinical importance of electrical cardiac stimulation has been recognized and renewed as Zoll (1911-1999) in 1952 reported a successful resuscitation in cardiac standstill by external stimulation. Meanwhile all over the world, millions of patients with cardiac arrhythmias have been treated with pacemakers in the last 45 years. The concept of a fully automatic implantable cardioverter-defibrillator system (ICD) for recognition and treatment of ventricular tachyarrhythmias was first suggested in 1970. The first implantation of the device in a human being was performed in February 1980. Further developments concern atrial and atrioventricular defibrillators, radiofrequency ablation, laser therapy and advanced antiarrhythmic surgery, new antiarrhythmic drugs and sophisticated devices for preventive pacing. The advances in the field of diagnostic and therapeutic application of pharmacologic and electrical tools as well as alternative methods will continue as rapidly as before in order to give us further significant aid in taking care of the patient.

  9. Electrophysiological fingerprints of OFF bipolar cells in rat retina

    PubMed Central

    Vielma, Alex H.; Schmachtenberg, Oliver

    2016-01-01

    Retinal bipolar cells (BCs) divide photoreceptor output into different channels for the parallel extraction of temporal and chromatic stimulus properties. In rodents, five types of OFF BCs have been differentiated, based on morphological and functional criteria, but their electrophysiological characterization remains incomplete. This study analyzed OFF BCs with the patch clamp technique in acute slices of rat retina. Their specific voltage-dependent currents and glutamate responses are shown to represent individual fingerprints which define the signal processing and filtering properties of each cell type and allow their unequivocal identification. Two additions to the rat BC repertoire are presented: OFF BC-2′, a variation of BC-2 with wider axonal arbours and prominent Na+ currents, is described for the first time in rodents, and OFF BC-3b, previously identified in mouse, is electrophysiologically characterized in rat. Moreover, the glutamate responses of rat OFF BCs are shown to be differentially sensitive to AMPA- and kainate-receptor blockers and to modulation by nitric oxide (NO) through a cGMP-dependent mechanism. These results contribute to our understanding of the diversity and function of bipolar cells in mammals. PMID:27457753

  10. Acute renal replacement therapy in children with diarrhea-associated hemolytic uremic syndrome: a single center 16 years of experience.

    PubMed

    Grisaru, Silviu; Morgunov, Melissa A; Samuel, Susan M; Midgley, Julian P; Wade, Andrew W; Tee, James B; Hamiwka, Lorraine A

    2011-01-01

    Acute kidney injury (AKI) is becoming more prevalent among hospitalized children, its etiologies are shifting, and new treatment modalities are evolving; however, diarrhea-associated hemolytic uremic syndrome (D+HUS) remains the most common primary disease causing AKI in young children. Little has been published about acute renal replacement therapy (ARRT) and its challenges in this population. We describe our single center's experience managing 134 pediatric patients with D+HUS out of whom 58 (43%) required ARRT over the past 16 years. In our cohort, all but one patient were started on peritoneal dialysis (PD). Most patients, 47 (81%), received acute PD on a pediatric inpatient ward. The most common recorded complications in our cohort were peritoneal fluid leaks 13 (22%), peritonitis 11 (20%), and catheter malfunction 5 (9%). Nine patients (16%) needed surgical revision of their PD catheters. There were no bleeding events related to PD despite a mean platelets count of 40.9 (±23.5) × 10(3)/mm(3) and rare use of platelets infusions. Despite its methodological limitations, this paper adds to the limited body of evidence supporting the use of acute PD as the primary ARRT modality in children with D+HUS.

  11. HEV infection as an aetiologic factor for acute hepatitis: experience from a tertiary hospital in Bangladesh.

    PubMed

    Mamun-Al-Mahtab; Rahman, Salimur; Khan, Mobin; Karim, Fazal

    2009-02-01

    Acute hepatitis is seen sporadically round the year in Bangladesh. The incidence of acute viral hepatitis E increases after floods as this allows sewerage contamination of piped and groundwater. The aim of this retrospective study was to assess the burden of hepatitis E virus (HEV infection) in Bangladesh. Patients attending the Hepatology Unit III of the Bangabandhu Sheikh Mujib Medical University, during June 2004-December 2006, were included in the study. All viral markers were tested by enzyme-linked immunosorbent assay. The study population was divided in four groups. Group 1 included 144 patients with acute viral hepatitis. The inclusion criteria were: nausea and/or vomiting, loss of appetite, serum bilirubin >200 micromol/L, raised serum transaminases, and prothrombin time >3 seconds prolonged beyond control value. In Group 2, there were 31 pregnant women with acute viral hepatitis. All the patients had prodrome, icterus, raised serum bilirubin and raised serum transaminase levels. Group 3 included 23 patients presenting with fulminant hepatic failure. In Group 4, 69 patients with cirrhosis of liver were included. They presented with features of decompensation for the first time. The inclusion criteria were: patients with established cirrhosis with jaundice and/or ascites and/or hepatic encephalopathy. In Group 1, 58.33% of the 144 patients had acute viral hepatitis E. In Group 2, 45.16% of the pregnant women also had acute viral hepatitis E. HEV was responsible for 56.52% cases of fulminant hepatic failure in Group 3. In 21.7% cases in Group 4, decompensation of cirrhosis was due to HEV. Acute viral hepatitis E in the third trimester of pregnancy and HEV-induced fulminant hepatic failure were associated with 80% of mortality despite the best possible care. In this clinical context, acute viral hepatitis E is the leading cause of wide spectrum of liver disease ranging from severe acute viral hepatitis, fulminant hepatic failure, to decompensation of liver in

  12. Pregnancy related acute kidney injury: A single center experience from the Kashmir Valley.

    PubMed

    Najar, M Saleem; Shah, A Rashid; Wani, I A; Reshi, A Rashid; Banday, K A; Bhat, M Ashraf; Saldanha, C L

    2008-10-01

    All patients admitted with pregnancy related acute renal failure (PRAKI) from June 2005 to May 2007 were studied with respect to etiology, clinical features, and outcome of PRAKI. Of 569 cases of acute kidney injury (AKI), 40 (7.02%) cases were related to gestational problems; the age of the patients ranged from 15 to 45 years. Septic abortion was the most common cause of PRAKI, accounting for 20 (50%) cases of which 15 (75%) cases occurred in the first and five (25%) in the second trimester. Other causes were antepartum hemorrhage: six cases (15%), toxemia of pregnancy: six cases (15%), acute gastroenteritis: three cases (7.5%), postpartum hemorrhage: two cases (5%), acute pyelonephritis: two cases (5%), and postpartum, acute kidney injury: one case (2.5%). Dialysis was needed in 60% of the cases and mortality was observed in 20% of the cases. PRAKI continues to be a major concern in our society, causing a high maternal mortality. Septic abortion which has virtually disappeared from developed countries, continues to be a major cause of PRAKI in our society. Hence, there is a need to halt the practice of illegal abortions and improve antenatal care.

  13. Low-energy x-ray irradiation for electrophysiological studies

    SciTech Connect

    Schauer, D.A.; Zeman, G.H.; Pellmar, T.C.

    1989-01-01

    High-dose-rate acute whole-body exposures have been the main focus of radiobiology research conducted at the Armed Forces Radiobiology Research Institute (AFRRI) for many years. Extensive quantitative studies have been conducted analyzing behavioral effects, radiation-induced syndromes, and combined injury phenomena. Tolliver and Pellmar initiated a study to evaluate radiation damage to brain neurophysiology. A 50-kVp molybdenum target/filter x-ray tube was installed inside a lead-shielded Faraday cage. High-dose rates of up to 1.54 Gy/min (17.4-keV weighted average photons) were used to conduct local in vitro irradiations of the hippocampal region of guinea pig brains. Electrophysiological recordings of subtle changes in neuronal activity indicate this system is suitable for this application.

  14. Electrophysiological assessment of brain function in severe malnutrition.

    PubMed

    Robinson, S; Young, R E; Golden, M H

    1995-11-01

    Brain function in 10 severely malnourished children and matched controls was assessed using spectral analysis of electroencephalographic responses to photic driving during slow-wave sleep. The percentage power in the classical EEG broad-band domains was derived from temporo-occipital records. The malnourished group (5-23 months old; z-score height-for-age -3.2 +/- 0.3, weight-for-height -2.5 +/- 0.3) were tested on admission and on discharge from hospital. No significant differences were found between admission and discharge. Significant differences were found between malnourished and control groups, in the alpha 1 band in the undriven EEG, and in the alpha/beta 1 power ratio while driving at 8 Hz. These electrophysiological abnormalities, persisting despite somatic rehabilitation, must be associated with the chronic rather than the acute aspects of malnutrition, and can index the deviation of brain function from normality.

  15. Electrophysiologic Evaluation of Psychogenic Movement Disorders

    PubMed Central

    Pal, Pramod Kumar

    2011-01-01

    Psychogenic movement disorders (PMD) are a group of disorders which are in the border zone between neurology and psychiatry. All necessary laboratory investigations should be done to rule out an underlying organic disorder. While clinical acumen of a trained movement disorder specialist may be sufficient to diagnose most PMD, there are clinical situations where electrophysiological tests are required either to rule out an organic movement disorder or even diagnose a PMD. Current electrophysiological test are most useful for tremor, followed by jerks and least for spasms or dystonia. Commonly used electrophysiologic tests include multichannel surface electromyography (EMG), accelerometry, electroencephalography time locked with EMG, premovement potential (Bereitschaftspotential), and somatosensory evoked potentials. Psychogenic tremor is a low frequency tremor with variable frequency and duration of EMG bursts, entrainable, has a high coherence with voluntary movements, and presence of coactivation sign. Patients with psychogenic jerks have well organized triphasic pattern of activation of agonist and antagonist muscles. The jerks are associated with EMG bursts of long duration (usually > 70 ms), long and variable latencies in stimulus induced jerks, absence of craniocaudal pattern of muscle recruitment in apparent startle response, and often a Breitschaftspotential (premovement potential) precedes the jerk. Electrophysiological characterization of psychogenic dystonia is difficult and the tests are usually performed to rule out organic dystonia with characteristic findings. Finally, caution should be exerted in interpreting the electrophysiological tests as both false positive and false negative diagnosis of PMD may still occur. PMID:24868388

  16. Electrophysiological indices of target and distractor processing in visual search.

    PubMed

    Hickey, Clayton; Di Lollo, Vincent; McDonald, John J

    2009-04-01

    Attentional selection of a target presented among distractors can be indexed with an event-related potential (ERP) component known as the N2pc. Theoretical interpretation of the N2pc has suggested that it reflects a fundamental mechanism of attention that shelters the cortical representation of targets by suppressing neural activity stemming from distractors. Results from fields other than human electrophysiology, however, suggest that attention does not act solely through distractor suppression; rather, it modulates the processing of both target and distractors. We conducted four ERP experiments designed to investigate whether the N2pc reflects multiple attentional mechanisms. Our goal was to reconcile ostensibly conflicting outcomes obtained in electrophysiological studies of attention with those obtained using other methodologies. Participants viewed visual search arrays containing one target and one distractor. In Experiments 1 through 3, the distractor was isoluminant with the background, and therefore, did not elicit early lateralized ERP activity. This work revealed a novel contralateral ERP component that appears to reflect direct suppression of the cortical representation of the distractor. We accordingly name this component the distractor positivity (P(D)). In Experiment 4, an ERP component associated with target processing was additionally isolated. We refer to this component as the target negativity (N(T)). We believe that the N2pc reflects the summation of the P(D) and N(T), and that these discrete components may have been confounded in earlier electrophysiological studies. Overall, this study demonstrates that attention acts on both target and distractor representations, and that this can be indexed in the visual ERP.

  17. Bridging therapies and liver transplantation in acute liver failure, 10 years of MARS experience from Finland.

    PubMed

    Kantola, T; Ilmakunnas, M; Koivusalo, A-M; Isoniemi, H

    2011-01-01

    Acute liver failure is a life-threatening condition in the absence of liver transplantation option. The aetiology of liver failure is the most important factor determining the probability of native liver recovery and prognosis of the patient. Extracorporeal liver assist devices like MARS (Molecular Adsorbent Recirculating System) may buy time for native liver recovery or serve as bridging therapy to liver transplantation, with reduced risk of cerebral complications. MARS treatment may alleviate hepatic encephalopathy even in patients with a completely necrotic liver. Taking this into account, better prognostic markers than hepatic encephalopathy should be used to assess the need for liver transplantation in acute liver failure.

  18. The experience of daily life of acutely admitted frail elderly patients one week after discharge from the hospital

    PubMed Central

    Andreasen, Jane; Lund, Hans; Aadahl, Mette; Sørensen, Erik E.

    2015-01-01

    Introduction Frail elderly are at higher risk of negative outcomes such as disability, low quality of life, and hospital admissions. Furthermore, a peak in readmission of acutely admitted elderly patients is seen shortly after discharge. An investigation into the daily life experiences of the frail elderly shortly after discharge seems important to address these issues. The aim of this study was to explore how frail elderly patients experience daily life 1 week after discharge from an acute admission. Methods The qualitative methodological approach was interpretive description. Data were gathered using individual interviews. The participants were frail elderly patients over 65 years of age, who were interviewed at their home 1 week after discharge from an acute admission to a medical ward. Results Four main categories were identified: “The system,” “Keeping a social life,” “Being in everyday life,” and “Handling everyday life.” These categories affected the way the frail elderly experienced daily life and these elements resulted in a general feeling of well-being or non-well-being. The transition to home was experienced as unsafe and troublesome especially for the more frail participants, whereas the less frail experienced this less. Conclusion and discussion Several elements and stressors were affecting the well-being of the participants in daily life 1 week after discharge. In particular, contact with the health care system created frustrations and worries, but also physical disability, loneliness, and inactivity were issues of concern. These elements should be addressed by health professionals in relation to the transition phase. Future interventions should incorporate a multidimensional and bio-psycho-social perspective when acutely admitted frail elderly are discharged. Stakeholders should evaluate present practice to seek to improve care across health care sectors. PMID:26037333

  19. Electrophysiological methods for Caenorhabditis elegans neurobiology.

    PubMed

    Goodman, Miriam B; Lindsay, Theodore H; Lockery, Shawn R; Richmond, Janet E

    2012-01-01

    Patch-clamp electrophysiology is a technique of choice for the biophysical analysis of the function of nerve, muscle, and synapse in Caenorhabditis elegans nematodes. Considerable technical progress has been made in C. elegans electrophysiology in the decade since the initial publication of this technique. Today, most, if not all, electrophysiological studies that can be done in larger animal preparations can also be done in C. elegans. This chapter has two main goals. The first is to present to a broad audience the many techniques available for patch-clamp analysis of neurons, muscles, and synapses in C. elegans. The second is to provide a methodological introduction to the techniques for patch clamping C. elegans neurons and body-wall muscles in vivo, including emerging methods for optogenetic stimulation coupled with postsynaptic recording. We also present samples of the cell-intrinsic and postsynaptic ionic currents that can be measured in C. elegans nerves and muscles.

  20. Electrophysiological characterization of membrane transport proteins.

    PubMed

    Grewer, Christof; Gameiro, Armanda; Mager, Thomas; Fendler, Klaus

    2013-01-01

    Active transport in biological membranes has been traditionally studied using a variety of biochemical and biophysical techniques, including electrophysiology. This review focuses on aspects of electrophysiological methods that make them particularly suited for the investigation of transporter function. Two major approaches to electrical recording of transporter activity are discussed: (a) artificial planar lipid membranes, such as the black lipid membrane and solid supported membrane, which are useful for studies on bacterial transporters and transporters of intracellular compartments, and (b) patch clamp and voltage clamp techniques, which investigate transporters in native cellular membranes. The analytical power of these methods is highlighted by several examples of mechanistic studies of specific membrane proteins, including cytochrome c oxidase, NhaA Na(+)/H(+) exchanger, ClC-7 H(+)/Cl(-) exchanger, glutamate transporters, and neutral amino acid transporters. These examples reveal the wealth of mechanistic information that can be obtained when electrophysiological methods are used in combination with rapid perturbation approaches.

  1. Electrophysiological Methods for C. elegans Neurobiology

    PubMed Central

    Goodman, Miriam B.; Lindsay, Theodore H.; Lockery, Shawn R.; Richmond, Janet E.

    2014-01-01

    Patch-clamp electrophysiology is the technique of choice for the biophysical analysis of the function of nerve, muscle, and synapse in C. elegans nematodes. Considerable technical progress has been made in C. elegans electrophysiology in the decade since the initial publication of this technique. Today, most, if not all electrophysiological studies that can be done in larger animal preparations can also be done in C. elegans. This chapter has two main goals. The first is to present to a broad audience the many techniques available for patch-clamp analysis of neurons, muscles, and synapses in C. elegans. The second is to provide a methodological introduction to the techniques for patch-clamping C. elegans neurons and body-wall muscles in vivo, including emerging methods for optogenetic stimulation coupled with post-synaptic recording. We also present samples of the cell-intrinsic and post-synaptic ionic currents that can be measured in C. elegans nerve and muscle. PMID:22226532

  2. A patient with acute aortic dissection presenting with bilateral stroke - A rare experience.

    PubMed

    Kowalska-Brozda, Olimpia; Brozda, Mateusz

    2015-01-01

    Acute aortic dissection is a rare, life-threatening condition requiring early recognition and proper treatment. Although chest pain remains the most frequent initial symptom, clinical manifestation of aortic dissection varies. Rarely aortic dissection starts with neurological symptoms such as ischemic stroke, which is usually right-sided. A danger of performing thrombolytic therapy in these patients exists if aortic dissection is overlooked. Herein, we present a case of a patient with acute aortic dissection without typical chest pain whose initial manifestation was bilateral stroke. The uncommon presentation which masked the underlying condition delayed implementation of appropriate management. Moreover, the late admission to hospital prevented the patient from administration of recombined tissue plasminogen activator that would certainly decrease chances of survival. Presented case highlights the need for thorough physical examination at admission to hospital in all patients with acute stroke and points out the necessity of proper clinical work-up including adequate aorta imaging modalities of patients with acute stroke and suggestive findings of aortic dissection.

  3. Acute confusion and unreal experiences in intensive care patients in relation to the ICU syndrome. Part II.

    PubMed

    Granberg, A; Engberg, I B; Lundberg, D

    1999-02-01

    The intensive care unit syndrome (ICU syndrome) is defined as an altered emotional state occurring in a highly stressful environment, which may manifest itself in various forms such as delirium, confusion, crazy dreams or unreal experiences. The purpose of this part of a study of patients' experiences is to describe and illuminate patients' experiences of acute confusion, disorientation, wakefulness, dreams and nightmares during and after their stay in the ICU. The data were obtained from 19 ventilated patients, who were interviewed twice and had stayed at least 36 hours in the ICU, the first interview being about one week after discharge from the ICU, and the second 4-8 weeks later. The hermeneutic approach used when interpreting and analysing the text from the interviews revealed that patients' experiences of unreal experiences were often associated with intense fear. Intense or continuous unbearable fear seems to result in frightening unreal experiences, which further increase the level of fear. Care actions or caring relationships with relatives or nurses can reduce this fear, which can help to prevent the occurrence and/or duration and intensity of the unreal experiences. Trust and confidence in nurses or significant others and feelings of self-control or trust in self-control seemed to reduce the risk of unreal experiences so that adverse stimuli might only trigger a mild confusion.

  4. Electrophysiological correlates of remembering emotional pictures.

    PubMed

    Schaefer, Alexandre; Pottage, Claire L; Rickart, Adam J

    2011-01-01

    Extensive evidence shows that emotional events tend to be remembered in greater detail and with an enhanced sense of vividness compared to neutral events. The current study investigated the neural correlates of this phenomenon during retrieval using the event-related potentials technique (ERP). Participants were asked to perform a memory recognition test of previously studied ("Old") and unstudied ("New") emotional and neutral pictures encoded a week before the test session. Next, they were asked to perform a Remember-Know task (Gardiner and Java, 1993) for each "old" decision. ERPs were created for retrieval activity corresponding to six conditions: Remember-Emotional, Remember-Neutral, Know-Emotional, Know-Neutral, New-Emotional and New-Neutral. Results showed that negative emotion enhanced three distinct subtypes of the electrophysiological old-new effect specifically for old items associated with a "Remember" judgment. This effect was observed for ERP old-new effects conforming to an early frontal P2 old-new effect peaking at ~180 ms, a midfrontal old-new effect starting at ~300 ms (the "FN400") and a late positive complex (LPC) with parietal maxima observed at 500-700 ms. In addition, a breakdown of our data in different levels of emotional arousal revealed that the relationship between ERP correlates of retrieval and arousal conformed to a nonlinear, inverted U-shaped function for posterior late effects (500-700) and to a linear function for early effects (P2 and FN400). Taken together, these results suggest that multiple retrieval subprocesses contribute to the emotional enhancement of recollective experience.

  5. Systemic Lupus Erythematosus, Radiotherapy, and the Risk of Acute and Chronic Toxicity: The Mayo Clinic Experience

    SciTech Connect

    Pinn, Melva E.; Gold, Douglas G. M.; Petersen, Ivy A.; Osborn, Thomas G.; Brown, Paul D.; Miller, Robert C.

    2008-06-01

    Purpose: To determine the acute and chronic toxic effects of radiotherapy in patients with systemic lupus erythematosus (SLE). Methods and Materials: Medical records of 21 consecutive patients with SLE, who had received 34 courses of external beam radiotherapy and one low-dose-rate prostate implant, were retrospectively reviewed. Patients with discoid lupus erythematosus were excluded. Results: Median survival was 2.3 years and median follow-up 5.6 years. Eight (42%) of 19 patients evaluable for acute toxicity during radiotherapy experienced acute toxicity of Grade 1 or greater, and 4 (21%) had acute toxicity of Grade 3 or greater. The 5- and 10-year incidence of chronic toxicity of Grade 1 or greater was 45% (95% confidence interval [CI], 22-72%) and 56% (95% CI, 28-81%), respectively. The 5- and 10-year incidence of chronic toxicity of Grade 3 or greater was 28% (95% CI, 18-60%) and 40% (95% CI, 16-72%), respectively. Univariate analysis showed that chronic toxicity of Grade 1 or greater correlated with SLE renal involvement (p < 0.006) and possibly with the presence of five or more American Rheumatism Association criteria (p < 0.053). Chronic toxicity of Grade 3 or greater correlated with an absence of photosensitivity (p < 0.02), absence of arthritis (p < 0.03), and presence of a malar rash (p < 0.04). Conclusions: The risk of acute and chronic toxicity in patients with SLE who received radiotherapy was moderate but was not prohibitive of the use of radiotherapy. Patients with more advanced SLE may be at increased risk for chronic toxicity.

  6. A qualitative study of patient experiences of decentralized acute healthcare services

    PubMed Central

    Linqvist Leonardsen, Ann-Chatrin; Del Busso, Lilliana; Abrahamsen Grøndahl, Vigdis; Ghanima, Waleed; Barach, Paul; Jelsness-Jørgensen, Lars-Petter

    2016-01-01

    Objective Municipality acute wards (MAWs) have recently been launched in Norway as an alternative to hospitalizations, and are aimed at providing treatment for patients who otherwise would have been hospitalized. The objective of this study was to explore how patients normally admitted to hospitals perceived the quality and safety of treatment in MAWs. Design The study had a qualitative design. Thematic analysis was used to analyze the data. Setting The study was conducted in a county in south-eastern Norway and included five different MAWs. Patients Semi-structured interviews were conducted with 27 participants who had required acute health care and who had been discharged from the five MAWs. Results Three subthemes were identified that related to the overarching theme of hospital-like standards (“almost a hospital, but…”), namely (a) treatment and competence, (b) location and physical environment, and (c) adequate time for care. Participants reported the treatment to be comparable to hospital care, but they also experienced limitations. Participants spoke positively about MAW personnel and the advantages of having a single patient room, a calm environment, and proximity to home. Conclusions Participants felt safe when treated at MAWs, even though they realized that the diagnostic services were not similar to that in hospitals. Geographical proximity, treatment facilities and time for care positively distinguished MAWs from hospitals, while the lack of diagnostic resources was stressed as a limitation. Key Points Municipality acute wards (MAWs) have been implemented across Norway. Research on patient perspectives on the decentralization of acute healthcare in MAWs is lacking.  • Patients perceive decentralized acute healthcare and treatment as being comparable to the quality they would have expected in hospitals.  • Geographical proximity, a home-like atmosphere and time for care were aspects stressed as positive features of the decentralized

  7. Severe acute respiratory syndrome vaccine development: experiences of vaccination against avian infectious bronchitis coronavirus.

    PubMed

    Cavanagh, Dave

    2003-12-01

    Vaccines against infectious bronchitis of chickens (Gallus gallus domesticus) have arguably been the most successful, and certainly the most widely used, of vaccines for diseases caused by coronaviruses, the others being against bovine, canine, feline and porcine coronaviruses. Infectious bronchitis virus (IBV), together with the genetically related coronaviruses of turkey (Meleagris gallopovo) and ring-necked pheasant (Phasianus colchicus), is a group 3 coronavirus, severe acute respiratory syndrome (SARS) coronavirus being tentatively in group 4, the other known mammalian coronaviruses being in groups 1 and 2. IBV replicates not only in respiratory tissues (including the nose, trachea, lungs and airsacs, causing respiratory disease), but also in the kidney (associated with minor or major nephritis), oviduct, and in many parts of the alimentary tract--the oesophagus, proventriculus, duodenum, jejunum, bursa of Fabricius, caecal tonsils (near the distal end of the tract), rectum and cloaca (the common opening for release of eggs and faeces), usually without clinical effects. The virus can persist, being re-excreted at the onset of egg laying (4 to 5 months of age), believed to be a consequence of the stress of coming into lay. Genetic lines of chickens differ in the extent to which IBV causes mortality in chicks, and in respect of clearance of the virus after the acute phase. Live attenuated (by passage in chicken embryonated eggs) IBV strains were introduced as vaccines in the 1950s, followed a couple of decades later by inactivated vaccines for boosting protection in egg-laying birds. Live vaccines are usually applied to meat-type chickens at 1 day of age. In experimental situations this can result in sterile immunity when challenged by virulent homologous virus. Although 100% of chickens may be protected (against clinical signs and loss of ciliary activity in trachea), sometimes 10% of vaccinated chicks do not respond with a protective immune response

  8. Endovascular Management of Acute Embolic Occlusion of the Superior Mesenteric Artery: A 12-Year Single-Centre Experience

    SciTech Connect

    Raupach, J. Lojik, M. Chovanec, V. Renc, O.; Strýček, M.; Dvořák, P. Hoffmann, P.; Guňka, I. Ferko, A.; Ryška, P.; Omran, N.; Krajina, A. Čabelková, P.; Čermáková, E.; Malý, R.

    2016-02-15

    PurposeRetrospective evaluation of 12-year experience with endovascular management of acute mesenteric ischemia (AMI) due to embolic occlusion of the superior mesenteric artery (SMA).Materials and methodsFrom 2003 to 2014, we analysed the in-hospital mortality of 37 patients with acute mesenteric embolism who underwent primary endovascular therapy with subsequent on-demand laparotomy. Transcatheter embolus aspiration was used in all 37 patients (19 women, 18 men, median age 76 years) with embolic occlusion of the SMA. Adjunctive local thrombolysis (n = 2) and stenting (n = 2) were also utilised.ResultsWe achieved complete recanalization of the SMA stem in 91.9 %. One patient was successfully treated by surgical embolectomy due to a failed endovascular approach. Subsequent exploratory laparotomy was performed in 73.0 % (n = 27), and necrotic bowel resection in 40.5 %. The total in-hospital mortality was 27.0 %.ConclusionPrimary endovascular therapy for acute embolic SMA occlusion with on-demand laparotomy is a recommended algorithm used in our centre to treat SMA occlusion. This combined approach for the treatment of AMI is associated with in-hospital mortality rate of 27.0 %.

  9. The differentiation syndrome in patients with acute promyelocytic leukemia: experience of the pethema group and review of the literature.

    PubMed

    Montesinos, Pau; Sanz, Miguel A

    2011-01-01

    Differentiation syndrome (DS), formerly known as retinoic acid syndrome, is the main life-threatening complication of therapy with differentiating agents (all-trans retinoic acid [ATRA] or arsenic trioxide [ATO]) in patients with acute promyelocytic leukemia (APL). The differentiation of leukemic blasts and promyelocytes induced by ATRA and/or ATO may lead to cellular migration, endothelial activation, and release of interleukins and vascular factors responsible of tissue damage. Roughly one quarter of patients with APL undergoing induction therapy will develop the DS, characterized by unexplained fever, acute respiratory distress with interstitial pulmonary infiltrates, and/or a vascular capillary leak syndrome leading to acute renal failure. Although the development of the DS, particularly of the severe form, is still associated with a significant increase in morbidity and mortality during induction, the early administration of high-dose dexamethasone at the onset of the first symptoms seems likely to have dramatically reduced the mortality rate of this complication. In this article, we will review the clinical features, incidence, prognostic factors, management, and outcome of the DS reported in the scientific literature. We will make focus in the experience of the three consecutive Programa Español de Tratamientos en Hematología trials (PETHEMA LPA96, LPA99, and LPA2005), in which more than one thousand patients were treated with ATRA plus idarubicin for induction.

  10. Intra-arterial thrombolysis in acute ischaemic stroke: experience with a superselective catheter embedded in the clot.

    PubMed Central

    Casto, L; Caverni, L; Camerlingo, M; Censori, B; Moschini, L; Servalli, M C; Partziguian, T; Belloni, G; Mamoli, A

    1996-01-01

    OBJECTIVES--To report experience of intra-arterial thrombolysis for acute stroke, performed with a microcatheter navigated into the intracranial circulation to impale the clot. METHODS--Patients were selected on the following criteria: (1) clinical examination suggesting a large vessel occlusion in stroke patients between 18 and 75 years; (2) no radiographic signs of large actual ischaemia on CT at admission; (3) angiographically documented occlusion of the middle cerebral artery (MCA) stem or of the basilar artery (BA), without occlusion of the ipsilateral extracranial internal carotid artery or of both the vertebral arteries; (4) end of the entire procedure within six hours of stroke. 12 patients with acute stroke were recruited, eight of whom had occlusion of the MCA stem and four of the BA. Urokinase was used as the thrombolytic agent. RESULTS--Complete recanalisation in six MCA stem and in two BA occurred, and partial recanalisation in two MCA stem and one BA. There was no recanalisation in one BA. A clinically silent haemorrhage occurred in two patients, and a parenchymal haematoma in one patient, all in MCA occlusions. At four months five patients achieved self sufficiency (four with MCA and one with BA occlusion). Six patients were dependent (three totally), and one died. CONCLUSIONS--The strict criteria of eligibility allowing the enrollment of very few patients and the procedure itself, requiring particular neuroradiological expertise, make this procedure not routine. Nevertheless, the approach can be considered a possible option for patients with acute ischaemic stroke. Images PMID:8648335

  11. Management of acute respiratory infections by community health volunteers: experience of Bangladesh Rural Advancement Committee (BRAC).

    PubMed Central

    Hadi, Abdullahel

    2003-01-01

    OBJECTIVE: To assess the role of management practices for acute respiratory infections (ARIs) in improving the competency of community health volunteers in diagnosing and treating acute respiratory infections among children. METHODS: Data were collected by a group of research physicians who observed the performance of a sample of 120 health volunteers in 10 sub-districts in Bangladesh in which Bangladesh Rural Advancement Committee (BRAC) had run a community-based ARI control programme since mid-1992. Standardized tests were conducted until the 95% interphysician reliability on the observation of clinical examination was achieved. FINDINGS:The sensitivity, specificity, and overall agreement rates in diagnosing and treating ARIs were significantly higher among the health volunteers who had basic training and were supervised routinely than among those who had not. CONCLUSION: Diagnosis and treatment of ARIs at the household level in developing countries are possible if intensive basic training and the close supervision of service providers are ensured. PMID:12764514

  12. Characteristics of Children with Acute Carbon Monoxide Poisoning in Ankara: A Single Centre Experience.

    PubMed

    Unsal Sac, Rukiye; Taşar, Medine Ayşin; Bostancı, İlknur; Şimşek, Yurda; Bilge Dallar, Yıldız

    2015-12-01

    The purpose of the study was to define characteristics of children with acute carbon monoxide poisoning. Eighty children hospitalized with acute carbon monoxide poisoning were recruited prospectively over a period of 12 months. Sociodemographic features, complaints and laboratory data were recorded. When the patient was discharged, necessary preventive measures to be taken were explained to parents. One month later, the parents were questioned during a control examination regarding the precautions that they took. The ages of the cases were between one month and 16 yr. Education levels were low in 86.2% of mothers and 52.6% of fathers. All families had low income and 48.8% did not have formal housing. The source of the acute carbon monoxide poisoning was stoves in 71.2% of cases and hot-water heaters in 28.8% of cases. Three or more people were poisoned at home in 85.1% of the cases. The most frequent symptoms of poisoning were headache and vertigo (58.8%). Median carboxyhemoglobin levels at admission to the hospital and discharge were measured as 19.5% and 1.1% (P < 0.001). When families were called for re-evaluation, it was determined that most of them had taken the necessary precautions after the poisoning incident (86.3%). This study determined that children with acute childhood carbon monoxide poisoning are usually from families with low socioeconomic and education levels. Education about prevention should be provided to all people who are at risk of carbon monoxide poisoning before a poisoning incident occurs.

  13. Characteristics of Children with Acute Carbon Monoxide Poisoning in Ankara: A Single Centre Experience

    PubMed Central

    Unsal Sac, Rukiye; Bostancı, İlknur; Şimşek, Yurda; Bilge Dallar, Yıldız

    2015-01-01

    The purpose of the study was to define characteristics of children with acute carbon monoxide poisoning. Eighty children hospitalized with acute carbon monoxide poisoning were recruited prospectively over a period of 12 months. Sociodemographic features, complaints and laboratory data were recorded. When the patient was discharged, necessary preventive measures to be taken were explained to parents. One month later, the parents were questioned during a control examination regarding the precautions that they took. The ages of the cases were between one month and 16 yr. Education levels were low in 86.2% of mothers and 52.6% of fathers. All families had low income and 48.8% did not have formal housing. The source of the acute carbon monoxide poisoning was stoves in 71.2% of cases and hot-water heaters in 28.8% of cases. Three or more people were poisoned at home in 85.1% of the cases. The most frequent symptoms of poisoning were headache and vertigo (58.8%). Median carboxyhemoglobin levels at admission to the hospital and discharge were measured as 19.5% and 1.1% (P < 0.001). When families were called for re-evaluation, it was determined that most of them had taken the necessary precautions after the poisoning incident (86.3%). This study determined that children with acute childhood carbon monoxide poisoning are usually from families with low socioeconomic and education levels. Education about prevention should be provided to all people who are at risk of carbon monoxide poisoning before a poisoning incident occurs. PMID:26713060

  14. Patient Experiences following Acute HIV Infection Diagnosis and Counseling in South Africa

    PubMed Central

    Wolpaw, Benjamin J.; Mathews, Catherine; Mtshizana, Yolisa; Chopra, Mickey; Hardie, Diana; Lurie, Mark N.; De Azevedo, Virginia; Jennings, Karen

    2014-01-01

    Individuals in the acute stage of HIV infection (AHI) have an elevated potential to transmit HIV and play a critical role in the growth of the epidemic. Routine identification and counseling of individuals during AHI could decrease transmission behavior during this key period. However, diagnosis of AHI may present challenges distinct from those experienced through diagnosis of established HIV infection. A study was conducted in a public youth clinic outside of Cape Town, South Africa, to identify and counsel individuals with acute stage HIV infection. In-depth interviews were conducted with patients following diagnosis. After counseling, patients were accepting of the testing regimen used to diagnose AHI. They used the knowledge of having been recently infected to identify the source of their infection, but did not retain or place importance on information regarding the increased ability to transmit HIV during the acute stage. Future interventions directed at the reduction of HIV transmission following diagnosis with AHI will need to find ways of making this information more salient, possibly through more culturally meaningful educational approaches. PMID:25153674

  15. Electrophysiological evaluation of psychogenic movement disorders.

    PubMed

    Kamble, Nitish L; Pal, Pramod Kumar

    2016-01-01

    Psychogenic movement disorders (PMD) include a group of neurological symptoms which cannot be explained by any organic syndrome. The diagnosis of PMD is challenging for both neurologist and psychiatrist. Electrophysiological examination is a useful tool to evaluate and support a diagnosis PMD. It includes a set of tests which are chosen appropriate to the clinical setting that provides objective criteria for the diagnosis of PMD. The various tests available include accelerometry, surface electromyography, electroencephalography, jerk locked back averaging and pre-movement potentials, somatosensory evoked potentials, transcranial magnetic stimulation (TMS) etc. Electrophysiologically psychogenic tremors display features of variability, entrainability, coactivation, distractibility and increase in the amplitude and frequency on mass loading. Movement related cortical potentials such as Bereitschaftspotential is seen in psychogenic myoclonus. Presence of triphasic contraction of muscles and absence of co-contraction suggests psychogenic myoclonus. Latency of C-reflex is longer in psychogenic myoclonus as compared to organic myoclonus. The role of TMS to differentiate psychogenic from organic dystonia is still not clear. In conclusion, electrophysiological tests are most useful for tremor, followed by jerks and least for dystonia. In patients with long-standing PMD or those with mixed pathology, electrophysiological tests may not be very useful.

  16. [Do We Still Need Electrophysiology in Ophthalmology?

    PubMed

    Tegetmeyer, H

    2016-12-01

    Electrophysiological methods in clinical ophthalmology include the full-field electroretinogram (ERG) for assessment of outer and middle retinal layers, pattern ERG (PERG) for assessment of ganglion cell function, the electrooculogram (EOG) for assessment of retinal pigment epithelium function, as well as visual evoked potentials (VEP) for assessment of the visual pathway, including the optic nerve and visual cortex. Multifocal recording techniques for ERG and VEP are used for tests within selected areas of the visual field. Technical progress in ocular imaging, especially optical coherence tomography (OCT) and fundus autofluorescence (FAF), allows high-resolution imaging of subtle morphological changes of the retina and posterior fundus. Typical retinal diseases may then be diagnosed at an early stage, without conventional electrophysiological investigations (e.g. x-linked retinoschisis, Stargardt disease, vitelliform macular dystrophy). OCT outclasses electrophysiological methods in the quantification of optic atrophies. With newly developed optic techniques, peripheral retinal structures (wide angle optics) and subtle structures up to the photoreceptor level (adaptive optics) can be imaged with increasing quality. However, differentiation of central retinal disorders (e.g. macular dystrophy) from generalised retinal diseases requires electrophysiological diagnostic testing. The same applies to discrimination between different functional disorders in generalised retinal diseases (e.g. enhanced S-cone syndrome, congenital stationary night blindness, achromatopsia).

  17. Electrophysiological assessment of retinal ganglion cell function

    PubMed Central

    Porciatti, Vittorio

    2015-01-01

    The function of retinal ganglion cells (RGCs) can be non-invasively assessed in experimental and genetic models of glaucoma by means of variants of the ERG technique that emphasize the activity of inner retina neurons. The best understood technique is the Pattern Electroretinogram (PERG) in response to contrast-reversing gratings or checkerboards, which selectively depends on the presence of functional RGCs. In glaucoma models, the PERG can be altered before histological loss of RGCs; PERG alterations may be either reversed with moderate IOP lowering or exacerbated with moderate IOP elevation. Under particular luminance-stimulus conditions, the Flash-ERG displays components that may reflect electrical activity originating in the proximal retina and be altered in some experimental glaucoma models (positive Scotopic Threshold response, pSTR; negative Scotopic Threshold Response, nSTR; Photopic Negative Response, PhNR; Oscillatory Potentials, OPs; multifocal ERG, mfERG). It is not yet known which of these components is most sensitive to glaucomatous damage. Electrophysiological assessment of RGC function appears to be a necessary outcome measure in experimental glaucoma models, which complements structural assessment and may even predict it. Neuroprotective strategies could be tested based on enhancement of baseline electrophysiological function that results in improved RGC survival. The use of electrophysiology in glaucoma models may be facilitated by specifically designed instruments that allow high throughput, robust assessment of electrophysiological function. PMID:25998495

  18. Electrophysiological Correlates of Observational Learning in Children

    ERIC Educational Resources Information Center

    Rodriguez Buritica, Julia M.; Eppinger, Ben; Schuck, Nicolas W.; Heekeren, Hauke R.; Li, Shu-Chen

    2016-01-01

    Observational learning is an important mechanism for cognitive and social development. However, the neurophysiological mechanisms underlying observational learning in children are not well understood. In this study, we used a probabilistic reward-based observational learning paradigm to compare behavioral and electrophysiological markers of…

  19. Portuguese National Registry on Cardiac Electrophysiology, 2013 and 2014.

    PubMed

    Cavaco, Diogo; Morgado, Francisco; Bonhorst, Daniel

    2016-01-01

    The authors present the results of the national registry of electrophysiology of the Portuguese Association for Arrhythmology, Pacing and Electrophysiology (APAPE) for 2013 and 2014. The registry is annual and voluntary, and data are collected retrospectively. Data for electrophysiological studies, ablations and cardioverter-defibrillator implantations for 2013 and 2014 are presented. Developments over the years and their implications are analyzed and discussed.

  20. Shared electrophysiology mechanisms of body ownership and motor imagery.

    PubMed

    Evans, Nathan; Blanke, Olaf

    2013-01-01

    Although we feel, see, and experience our hands as our own (body or hand ownership), recent research has shown that illusory hand ownership can be induced for fake or virtual hands and may be useful for neuroprosthetics and brain-computer interfaces. Despite the vast amount of behavioral data on illusory hand ownership, neuroimaging studies are rare, in particular electrophysiological studies. Thus, while the neural systems underlying hand ownership are relatively well described, the spectral signatures of body ownership as measured by electroencephalography (EEG) remain elusive. Here we induced illusory hand ownership in an automated, computer-controlled manner using virtual reality while recording 64-channel EEG and found that illusory hand ownership is reflected by a body-specific modulation in the mu-band over fronto-parietal cortex. In a second experiment in the same subjects, we then show that mu as well as beta-band activity in highly similar fronto-parietal regions was also modulated during a motor imagery task often used in paradigms employing non-invasive brain-computer interface technology. These data provide insights into the electrophysiological brain mechanisms of illusory hand ownership and their strongly overlapping mechanisms with motor imagery in fronto-parietal cortex. They also highlight the potential of combining high-resolution EEG with virtual reality setups and automatized stimulation protocols for systematic, reproducible stimulus presentation in cognitive neuroscience, and may inform the design of non-invasive brain-computer interfaces.

  1. Public Health Response Systems In-Action: Learning from Local Health Departments’ Experiences with Acute and Emergency Incidents

    PubMed Central

    Hunter, Jennifer C.; Yang, Jane E.; Crawley, Adam W.; Biesiadecki, Laura; Aragón, Tomás J.

    2013-01-01

    As part of their core mission, public health agencies attend to a wide range of disease and health threats, including those that require routine, acute, and emergency responses. While each incident is unique, the number and type of response activities are finite; therefore, through comparative analysis, we can learn about commonalities in the response patterns that could improve predictions and expectations regarding the resources and capabilities required to respond to future acute events. In this study, we interviewed representatives from more than 120 local health departments regarding their recent experiences with real-world acute public health incidents, such as infectious disease outbreaks, severe weather events, chemical spills, and bioterrorism threats. We collected highly structured data on key aspects of the incident and the public health response, particularly focusing on the public health activities initiated and community partners engaged in the response efforts. As a result, we are able to make comparisons across event types, create response profiles, and identify functional and structural response patterns that have import for future public health preparedness and response. Our study contributes to clarifying the complexity of public health response systems and our analysis reveals the ways in which these systems are adaptive to the character of the threat, resulting in differential activation of functions and partners based on the type of incident. Continued and rigorous examination of the experiences of health departments throughout the nation will refine our very understanding of what the public health response system is, will enable the identification of organizational and event inputs to performance, and will allow for the construction of rich, relevant, and practical models of response operations that can be employed to strengthen public health systems. PMID:24236137

  2. Spectrum of glomerular diseases causing acute kidney injury; 25 years experience from a single center

    PubMed Central

    Naqvi, Rubina; Mubarak, Muhammed; Ahmed, Ejaz; Akhtar, Fazal; Bhatti, Sajid; Naqvi, Anwar; Rizvi, Adib

    2015-01-01

    Introduction: Acute kidney injury (AKI) is common in nephro-urological practice. Its incidence, prevalence and etiology vary widely, mainly due to variations in the definitions of AKI. Objectives: We aim to report the spectrum of glomerular diseases presenting as AKI at a kidney referral center in Pakistan. Patients and Methods: An observational cohort of patients identified as having AKI which was defined according to RIFLE criteria, with normal size, non-obstructed kidneys on ultrasonography, along with active urine sediment, edema and new onset hypertension. Results: From 1990 to 2014, 236 cases of AKI secondary to acute glomerulonephritis (AGN) registered at this institution. Mean age of patients was 27.94± 12.79 years and M:F ratio was 0.77:1. Thirty percent patients revealed crescents on renal biopsy. AGN without crescents was seen in 33.05% of cases. Postinfectious GN was found in 14.4%, lupus nephritis in 8.5% and mesangiocapillary GN in 3.4% cases. Renal replacement therapy (RRT) required in 75.84% patients. Pulse steroids were given in 45.33% cases followed by oral steroids. Pulse cyclophoshphamide was given in 23.7% cases and plasmapheresis was used in 3.38% cases. Complete recovery was seen in 44%, while 11.44% died during acute phase of illness. About 19.49 % developed chronic kidney disease (CKD) and 25.84% were lost to long- term follow-up. Conclusion: Although glomerular diseases contribute only 4.19 % of total AKI at this center, morbidity associated with illness and its treatment is more marked than other AKI groups. Another notable factor is late referral of these patients to specialized centers resulting in undesirable outcome. PMID:26693497

  3. Herpes labialis in patients with Russell's viper bite and acute kidney injury: a single center experience.

    PubMed

    Waikhom, Rajesh; Sapam, Ranjeeta; Patil, Krishna; Jadhav, Jaya Prada; Sircar, Dipankar; Roychowdhury, Arpita; Dasgupta, Sanjay; Pandey, Rajendra

    2011-06-01

    Snake bite is an important health hazard in tropical countries and is associated with significant morbidity and mortality. Herpes labialis is a common ailment caused by the Herpes simplex virus. There is no published data showing any association between the snake bite and development of Herpes labialis. Here, we present a series of patients who developed Herpes labialis after Russell's viper bite and had acute kidney injury. We attempted to find whether snake bite is an immunosuppressed state and whether it could have pre-disposed the patients to the development of these lesions.

  4. Neonatal experience interacts with adult social stress to alter acute and chronic Theiler's virus infection.

    PubMed

    Johnson, R R; Maldonado Bouchard, S; Prentice, T W; Bridegam, P; Rassu, F; Young, C R; Steelman, A J; Welsh, T H; Welsh, C J; Meagher, M W

    2014-08-01

    Previous research has shown that neonatal handling has prolonged protective effects associated with stress resilience and aging, yet little is known about its effect on stress-induced modulation of infectious disease. We have previously demonstrated that social disruption stress exacerbates the acute and chronic phases of the disease when applied prior to Theiler's virus infection (PRE-SDR) whereas it attenuates disease severity when applied concurrently with infection (CON-SDR). Here, we asked whether neonatal handling would protect adult mice from the detrimental effects of PRE-SDR and attenuate the protective effects of CON-SDR on Theiler's virus infection. As expected, handling alone decreased IL-6 and corticosterone levels, protected the non-stressed adult mice from motor impairment throughout infection and reduced antibodies to myelin components (PLP, MBP) during the autoimmune phase of disease. In contrast, neonatal handling X PRE/CON-SDR elevated IL-6 and reduced corticosterone as well as increased motor impairment during the acute phase of the infection. Neonatal handling X PRE/CON-SDR continued to exacerbate motor impairment during the chronic phase, whereas only neonatal handling X PRE-SDR increased in antibodies to PLP, MOG, MBP and TMEV. Together, these results imply that while handling reduced the severity of later Theiler's virus infection in non-stressed mice, brief handling may not be protective when paired with later social stress.

  5. Acute pancreatitis patient registry to examine novel therapies in clinical experience (APPRENTICE): an international, multicenter consortium for the study of acute pancreatitis

    PubMed Central

    Papachristou, Georgios I.; Machicado, Jorge D.; Stevens, Tyler; Goenka, Mahesh Kumar; Ferreira, Miguel; Gutierrez, Silvia C.; Singh, Vikesh K.; Kamal, Ayesha; Gonzalez-Gonzalez, Jose A.; Pelaez-Luna, Mario; Gulla, Aiste; Zarnescu, Narcis O.; Triantafyllou, Konstantinos; Barbu, Sorin T.; Easler, Jeffrey; Ocampo, Carlos; Capurso, Gabriele; Archibugi, Livia; Cote, Gregory A.; Lambiase, Louis; Kochhar, Rakesh; Chua, Tiffany; Tiwari, Subhash Ch.; Nawaz, Haq; Park, Walter G.; de-Madaria, Enrique; Lee, Peter J.; Wu, Bechien U.; Greer, Phil J.; Dugum, Mohannad; Koutroumpakis, Efstratios; Akshintala, Venkata; Gougol, Amir

    2017-01-01

    Background We have established a multicenter international consortium to better understand the natural history of acute pancreatitis (AP) worldwide and to develop a platform for future randomized clinical trials. Methods The AP patient registry to examine novel therapies in clinical experience (APPRENTICE) was formed in July 2014. Detailed web-based questionnaires were then developed to prospectively capture information on demographics, etiology, pancreatitis history, comorbidities, risk factors, severity biomarkers, severity indices, health-care utilization, management strategies, and outcomes of AP patients. Results Between November 2015 and September 2016, a total of 20 sites (8 in the United States, 5 in Europe, 3 in South America, 2 in Mexico and 2 in India) prospectively enrolled 509 AP patients. All data were entered into the REDCap (Research Electronic Data Capture) database by participating centers and systematically reviewed by the coordinating site (University of Pittsburgh). The approaches and methodology are described in detail, along with an interim report on the demographic results. Conclusion APPRENTICE, an international collaboration of tertiary AP centers throughout the world, has demonstrated the feasibility of building a large, prospective, multicenter patient registry to study AP. Analysis of the collected data may provide a greater understanding of AP and APPRENTICE will serve as a future platform for randomized clinical trials. PMID:28042246

  6. Analysis of multiple sclerosis patients with electrophysiological and structural tests.

    PubMed

    Hamurcu, Mualla; Orhan, Gürdal; Sarıcaoğlu, Murat Sinan; Mungan, Semra; Duru, Zeynep

    2016-08-18

    We aimed to analyze the effects of progressive myelin loss and neurodegeneration seen in patients with multiple sclerosis (MS) on visual tract with electrophysiological and structural tests. Fifty-one patients diagnosed with MS in the Neurology Department were followed up in neuro-ophthalmology outpatient clinic irrespective of their visual symptoms, and were included in our study. The patients were classified as the ones with the history of optic neuritis (group II) and ones without the history (group I) of optic neuritis. The data, including clinical presentation, retinal nerve fiber layer thickness (RNFLT) measurements, pattern visual evoked potential (pVEP) and flash electro retino grams (ERG) test results, were recorded. In our study, comparison of pVEP test latencies of groups I and II with each other, and with those of healthy subjects revealed statistically significant differences (p < 0.05). The analysis of rod functions on ERG did not show any significant changes (p > 0.05). However, both groups showed significantly decreased cone b-wave amplitudes, elongation of latencies, and decreased flicker amplitudes on cone and flicker potentials obtained after light adaptation (p < 0.05). There was significant thinning in RNFLT of the both groups when compared to the normal standards. The difference between two groups was statistically significant (p < 0.05). Axon loss is seen in the optic nerve with subclinical or acute optic neuritis in patients with MS. RNFLT analysis and electrophysiological tests are of great importance in diagnosis of MS, as well as to determine progression and to direct neuroprotective therapy in patients diagnosed with MS. Objective analysis methods gain more importance in the diagnosis and follow-up of MS patients, parallel to technological advancements.

  7. Electrophysiological Monitoring in Patients With Tumors of the Skull Base Treated by Carbon-12 Radiation Therapy

    SciTech Connect

    Carozzo, Simone; Schardt, Dieter; Narici, Livio; Combs, Stephanie E.; Debus, Jürgen; Sannita, Walter G.

    2013-03-15

    Purpose: To report the results of short-term electrophysiologic monitoring of patients undergoing {sup 12}C therapy for the treatment of skull chordomas and chondrosarcomas unsuitable for radical surgery. Methods and Materials: Conventional electroencephalogram (EEG) and retinal and cortical electrophysiologic responses to contrast stimuli were recorded from 30 patients undergoing carbon ion radiation therapy, within a few hours before the first treatment and after completion of therapy. Methodologies and procedures were compliant with the guidelines of the International Federation for Clinical Neurophysiology and International Society for Clinical Electrophysiology of Vision. Results: At baseline, clinical signs were reported in 56.6% of subjects. Electrophysiologic test results were abnormal in 76.7% (EEG), 78.6% (cortical evoked potentials), and 92.8% (electroretinogram) of cases, without correlation with neurologic signs, tumor location, or therapy plan. Results on EEG, but not electroretinograms and cortical responses, were more often abnormal in patients with reported clinical signs. Abnormal EEG results and retinal/cortical responses improved after therapy in 40% (EEG), 62.5% (cortical potentials), and 70% (electroretinogram) of cases. Results on EEG worsened after therapy in one-third of patients whose recordings were normal at baseline. Conclusions: The percentages of subjects whose EEG results improved or worsened after therapy and the improvement of retinal/cortical responses in the majority of patients are indicative of a limited or negligible (and possibly transient) acute central nervous system toxicity of carbon ion therapy, with a significant beneficial effect on the visual pathways. Research on large samples would validate electrophysiologic procedures as a possible independent test for central nervous system toxicity and allow investigation of the correlation with clinical signs; repeated testing over time after therapy would demonstrate, and may

  8. Capacity for care: meta-ethnography of acute care nurses' experiences of the nurse-patient relationship

    PubMed Central

    Bridges, Jackie; Nicholson, Caroline; Maben, Jill; Pope, Catherine; Flatley, Mary; Wilkinson, Charlotte; Meyer, Julienne; Tziggili, Maria

    2013-01-01

    Aims To synthesize evidence and knowledge from published research about nurses' experiences of nurse-patient relationships with adult patients in general, acute inpatient hospital settings. Background While primary research on nurses' experiences has been reported, it has not been previously synthesized. Design Meta-ethnography. Data sources Published literature from Australia, Europe, and North America, written in English between January 1999–October 2009 was identified from databases: CINAHL, Medline, British Nursing Index and PsycINFO. Review methods Qualitative studies describing nurses' experiences of the nurse-patient relationship in acute hospital settings were reviewed and synthesized using the meta-ethnographic method. Results Sixteen primary studies (18 papers) were appraised as high quality and met the inclusion criteria. The findings show that while nurses aspire to develop therapeutic relationships with patients, the organizational setting at a unit level is strongly associated with nurses' capacity to build and sustain these relationships. The organizational conditions of critical care settings appear best suited to forming therapeutic relationships, while nurses working on general wards are more likely to report moral distress resulting from delivering unsatisfactory care. General ward nurses can then withdraw from attempting to emotionally engage with patients. Conclusion The findings of this meta-ethnography draw together the evidence from several qualitative studies and articulate how the organizational setting at a unit level can strongly influence nurses' capacity to build and sustain therapeutic relationships with patients. Service improvements need to focus on how to optimize the organizational conditions that support nurses in their relational work with patients. PMID:23163719

  9. Electrophysiological Recording in the Brain of Intact Adult Zebrafish

    PubMed Central

    Johnston, Lindsey; Ball, Rebecca E.; Acuff, Seth; Gaudet, John; Sornborger, Andrew; Lauderdale, James D.

    2013-01-01

    Previously, electrophysiological studies in adult zebrafish have been limited to slice preparations or to eye cup preparations and electrorentinogram recordings. This paper describes how an adult zebrafish can be immobilized, intubated, and used for in vivo electrophysiological experiments, allowing recording of neural activity. Immobilization of the adult requires a mechanism to deliver dissolved oxygen to the gills in lieu of buccal and opercular movement. With our technique, animals are immobilized and perfused with habitat water to fulfill this requirement. A craniotomy is performed under tricaine methanesulfonate (MS-222; tricaine) anesthesia to provide access to the brain. The primary electrode is then positioned within the craniotomy window to record extracellular brain activity. Through the use of a multitube perfusion system, a variety of pharmacological compounds can be administered to the adult fish and any alterations in the neural activity can be observed. The methodology not only allows for observations to be made regarding changes in neurological activity, but it also allows for comparisons to be made between larval and adult zebrafish. This gives researchers the ability to identify the alterations in neurological activity due to the introduction of various compounds at different life stages. PMID:24300281

  10. Correlations of clinical, neuroimaging, and electrophysiological features in Hirayama disease

    PubMed Central

    Liao, Ming-Feng; Chang, Hong-Shiu; Chang, Kuo-Hsuan; Ro, Long-Sun; Chu, Chun-Che; Kuo, Hung-Chou; Lyu, Rong-Kuo

    2016-01-01

    Abstract Hirayama disease (HD) is characterized by development of asymmetric forearm muscle atrophy during adolescence with or without focal cervical spinal cord atrophy. The purpose of this study is to assess the correlation of clinical symptoms, disease progression, and electrophysiological findings with cervical spine magnetic resonance imaging (MRI) findings. The medical records, cervical spine MRIs, and electrophysiological findings of 44 HD patients were retrospectively reviewed and analyzed. Denervation changes in any single C5 to C7 root-innervated muscle (deltoid, biceps, triceps, or extensor digitorum communis) occurred more frequently in the 25 patients with cord atrophy than the 19 patients without cord atrophy (88% vs 53%, P = 0.02). Onset age, duration of disease progression, neurological examinations, nerve conduction study, and electromyographic findings from individual muscles were similar between patient groups. Compared with HD patients without cord atrophy, HD patients with cord atrophy experience a more severe denervation change in C5 to C7 root-innervated muscles. PMID:27428223

  11. Institutional experience with clofarabine and cytarabine in relapsed pediatric acute myeloid leukemia.

    PubMed

    Moreno, Lucas; Fernandez-Navarro, Jose Maria; Del Mar Andres, Maria; Bautista, Francisco; Tasso, Maria; Verdeguer, Amparo

    2012-01-01

    Cytarabine (1000 mg/m/d intravenous for 5 d) and clofarabine (40 mg/m/d intravenous for 5 d) were given every 28 days to 9 children with relapsed acute myeloid leukemia at our institution. Among 19 courses, there were 18 infectious episodes. Median hospitalization time was 13 days (7.7 to 30.5 d) per cycle. Hepatobiliary abnormalities included alanine aminotransferase/aspartate aminotransferase elevation and hyperbilirubinemia. Four patients achieved complete remission (one after an earlier allogeneic Haematopoietic Progenitor Cell Transplant). Four patients are alive disease free. In summary, a proportion of children responded and was able to receive allogeneic Haematopoietic Progenitor Cell Transplant. Side effects were tolerable, although hospitalization time was prolonged.

  12. Evidence of coupling to Global Alfv{acute e}ne Eigenmodes during Alfv{acute e}n wave current drive experiments on the Phaedrus-T tokamak

    SciTech Connect

    Vukovic, M.; Wukitch, S.; Harper, M.; Parker, R.

    1996-02-01

    A series of experiments designed to explore mechanisms of power deposition during Alfv{acute e}n wave current drive experiments on the Phaedrus-T tokamak has shown evidence of power deposition via mode conversion of Global Alfv{acute e}n Eigenmodes at the Alfv{acute e}n resonance. Observation of radially localized RF induced density fluctuations in the plasma and their location vs. {ital B}{sub {ital T}} is in agreement with the predictions of behaviour of GAE damping on the AR by the toroidal code LION. Furthermore, the change in the time evolution of the loop voltage, is consistent with the change of effective power deposition radius, {ital r}{sub PD}, and is in agreement with the density fluctuations radius. {copyright} {ital 1996 American Institute of Physics.}

  13. Blood soluble drag-reducing polymers prevent lethality from hemorrhagic shock in acute animal experiments.

    PubMed

    Kameneva, Marina V; Wu, Zhongjun J; Uraysh, Arkady; Repko, Brandon; Litwak, Kenneth N; Billiar, Timothy R; Fink, Mitchell P; Simmons, Richard L; Griffith, Bartley P; Borovetz, Harvey S

    2004-01-01

    Over the past several decades, blood-soluble drag reducing polymers (DRPs) have been shown to significantly enhance hemodynamics in various animal models when added to blood at nanomolar concentrations. In the present study, the effects of the DRPs on blood circulation were tested in anesthetized rats exposed to acute hemorrhagic shock. The animals were acutely resuscitated either with a 2.5% dextran solution (Control) or using the same solution containing 0.0005% or 5 parts per million (ppm) concentration of one of two blood soluble DRPs: high molecular weight (MW=3500 kDa) polyethylene glycol (PEG-3500) or a DRP extracted from Aloe vera (AVP). An additional group of animals was resuscitated with 0.0075% (75 ppm) polyethylene glycol of molecular weight of 200 kDa (PEG-200), which possesses no drag-reducing ability. All of the animals were observed for two hours following the initiation of fluid resuscitation or until they expired. We found that infusion of the DRP solutions significantly improved tissue perfusion, tissue oxygenation, and two-hour survival rate, the latter from 19% (Control) and 14% (PEG-200) to 100% (AVP) and 100% (PEG-3500). Furthermore, the Control and PEG-200 animals that survived required three times more fluid to maintain their blood pressure than the AVP and PEG-3500 animals. Several hypotheses regarding the mechanisms underlying these observed beneficial hemodynamic effects of DRPs are discussed. Our findings suggest that the drag-reducing polymers warrant further investigation as a potential clinical treatment for hemorrhagic shock and possibly other microcirculatory disorders.

  14. Impact of acute ischemic stroke treatment in patients over age 80: the SPOTRIAS consortium experience

    PubMed Central

    Willey, Joshua Z; Ortega-Gutierrez, Santiago; Petersen, Nils; Khatri, Pooja; Ford, Andria L; Rost, Natalia S; Ali, Latisha K; Gonzales, Nichole R; Merino, Jose G; Meyer, Brett C; Marshall, Randolph S

    2012-01-01

    Background and Purpose Few studies have addressed outcomes among patients ≥80 years treated with acute stroke therapy. In this study, we outline in-hospital outcomes in (1) patients ≥80 years compared to their younger counterparts, and (2) those over age 80 receiving intra-arterial therapy (IAT) compared to those treated with intravenous recombinant tissue plasminogen activator (IVrtPA). Methods Stroke centers within the Specialized Program of Translational Research in Acute Stroke (SPOTRIAS) prospectively collected data on all patients treated with IVrtPA or IAT from 1/1/2005 to 12/31/2010. IAT was defined as receiving any endovascular therapy; IAT was further divided into bridging therapy (BT) when the patient received both IAT and IVrtPA, and endovascular therapy alone (ETA). In-hospital mortality was compared in (1) all patients age ≥80 versus younger counter-parts, and (2) IAT, BT, and ETA versus IVrtPA only among those age ≥80 using multivariable logistic regression. An age-stratified analysis was also performed. Results A total of 3768 patients were included in the study; 3378 were treated with IVrtPA alone, 808 with IAT (383 with ETA and 425 with BT). Patients ≥80 (n=1182) had a higher risk of in-hospital mortality compared to younger counterparts regardless of treatment modality (OR 2.13, 95%CI 1.60–2.84). When limited to those age ≥80, IAT (OR 0.95, 95%CI 0.60–1.49), BT (OR 0.82, 95%CI 0.47–1.45), or ETA (OR 1.15, 95%CI 0.64–2.08) versus IVrtPA were not associated with increased in-hospital mortality Conclusions IAT does not appear to increase the risk of in-hospital mortality among those over age 80 compared to intravenous thrombolysis alone. PMID:22798327

  15. Paediatric Electrophysiologic Studies: How and What With?

    PubMed Central

    Sreeram, N; Emmel, M; Trieschmann, U; de Haan, E

    2008-01-01

    Catheter ablation of arrhythmias in children has become standard practice virtually worldwide. Successful and safe ablation has been made possible by a combination of factors. These include increased operator experience, a better understanding of the natural history of a wide variety of arrhythmias, advances in technology such as smaller catheters, the routine use of various three-dimensional mapping systems, and the development of alternative energy sources. It is also not uncommon to perform multiple catheter intervention procedures (ablation ± intravascular stent implantation ± device closure of residual shunts ± elective pacemaker or device implantation) during a single session. It is important to bear in mind that arrhythmia recurrence is commoner in children in general, and that this is particularly the case with postoperative (scar-related arrhythmias). Despite acute success, long-term follow-up is mandated for this subgroup of patients. PMID:18478065

  16. The Impact of Opioids on Cardiac Electrophysiology.

    PubMed

    Wedam, Erich F; Haigney, Mark C

    2016-01-01

    Synthetic opioid agents have been used in modern medicine for over a century and for opioid addiction treatment for over a half-century. Liberal use of opioids in the United States has been attended by an extraordinary increase in opioid-related mortality, with over 16,000 deaths in 2012. As there have been advances in opioid agents for pain and addiction, so have there been advances in our understanding of the cardiac effects of these agents. In the last 10 years, significant data regarding electrophysiologic effects of these agents have been collected. We aim in this review to discuss the effects on cardiac electrophysiology of the various opioid agents currently in use and the evidence that these effects are contributing to the rise in opioid-related mortality.

  17. Python for large-scale electrophysiology.

    PubMed

    Spacek, Martin; Blanche, Tim; Swindale, Nicholas

    2008-01-01

    Electrophysiology is increasingly moving towards highly parallel recording techniques which generate large data sets. We record extracellularly in vivo in cat and rat visual cortex with 54-channel silicon polytrodes, under time-locked visual stimulation, from localized neuronal populations within a cortical column. To help deal with the complexity of generating and analysing these data, we used the Python programming language to develop three software projects: one for temporally precise visual stimulus generation ("dimstim"); one for electrophysiological waveform visualization and spike sorting ("spyke"); and one for spike train and stimulus analysis ("neuropy"). All three are open source and available for download (http://swindale.ecc.ubc.ca/code). The requirements and solutions for these projects differed greatly, yet we found Python to be well suited for all three. Here we present our software as a showcase of the extensive capabilities of Python in neuroscience.

  18. The Impact of Opioids on Cardiac Electrophysiology

    PubMed Central

    Wedam, Erich F.; Haigney, Mark C.

    2016-01-01

    Synthetic opioid agents have been used in modern medicine for over a century and for opioid addiction treatment for over a half-century. Liberal use of opioids in the United States has been attended by an extraordinary increase in opioid-related mortality, with over 16,000 deaths in 2012. As there have been advances in opioid agents for pain and addiction, so have there been advances in our understanding of the cardiac effects of these agents. In the last 10 years, significant data regarding electrophysiologic effects of these agents have been collected. We aim in this review to discuss the effects on cardiac electrophysiology of the various opioid agents currently in use and the evidence that these effects are contributing to the rise in opioid-related mortality. PMID:26818485

  19. Acute Motor Conduction Block Neuropathy: Another Distinct Variant of Guillain-Barre Syndrome

    PubMed Central

    ERDOĞMUŞ İNCE, Nilüfer; ÖZTEKİN, M. Fevzi; ÖZTEKİN, Neşe

    2014-01-01

    We describe a patient who developed progressive weakness in all limbs without sensory symptoms 4 weeks after upper respiratory system infection. Electrophysiological findings suggested a new variant of Guillain-Barré syndrome named “acute motor conduction block neuropathy”. Electrophysiological studies were performed at admission, 12th and 28th weeks. At the 28th week, the clinical examination and electrophysiological findings showed complete recovery.

  20. Who experiences seclusion? An examination of demographics and duration in a public acute inpatient mental health service.

    PubMed

    Chavulak, Jacinta; Petrakis, Melissa

    2017-03-21

    Restrictive interventions such as seclusion may occur during an acute mental health crisis. Such interventions are experienced by people as traumatic and counter to recovery. The current study aimed to investigate the use of seclusion and who was secluded amongst patients presenting with psychotic symptomology. All acute inpatient admissions were examined across a 12-month period January-December 2013. Electronic and paper records were accessed and audited for all 655 admissions. There were 91 admissions that included a seclusion and 200 seclusion events. There were 79 unique patients who experienced seclusion. For those experiencing seclusion: two-thirds were male, 49% were either homeless or had no fixed abode, 32% received case management in the community prior to their inpatient stay, and 56% were unemployed or not in the workforce. The median and mode duration of seclusion was 4 h. By understanding seclusion interventions better, changes can be made to enhance practice. This descriptive research into seclusion has clarified the demographics of who is most likely to experience seclusion, for how long, and the implications for reducing restrictive interventions. How the social work role could contribute to reforms to protect and enhance the rights and well-being of marginalized members of our communities, at their most vulnerable, is considered.

  1. Electrophysiological methods for hearing assessment in pinnipeds

    NASA Astrophysics Data System (ADS)

    Reichmuth Kastak, Colleen; Kastak, David; Finneran, James J.; Houser, Dorian S.; Supin, Alexander

    2005-04-01

    Studies of auditory sensitivity in marine mammals generally rely on behavioral psychophysical methodologies. While these studies are the standard for hearing assessment in marine mammals, data are limited to only a few individuals representing a small proportion of species. Accumulating research on dolphin auditory physiology has resulted in the refinement of electrophysiological methods appropriate for odontocete cetaceans and an increase in available audiometric information. Electrophysiological methods have also been used with pinnipeds, but there are significant gaps in our understanding of pinniped auditory physiology that must be addressed before such appoaches can be broadly applied to investigations of pinniped hearing. We are taking a bottom-up approach to developing suitable methods for evoked potential audiometry in pinnipeds, including technology transfer from studies of cetaceans and other mammals, mapping of response amplitude with respect to recording positions on the skull, characterization of responses in relationship to various stimulus types and presentation parameters, and determination of whether useful frequency-specific data can be reliably obtained using electrophysiological methods. This approach is being taken with representative pinniped species including California sea lions (Zalophus californianus), harbor seals (Phoca vitulina), and northern elephant seals (Mirounga angustirostris) using both training and chemical immobilization techniques. [Work supported by NOPP.

  2. Benchmarking electrophysiological models of human atrial myocytes

    PubMed Central

    Wilhelms, Mathias; Hettmann, Hanne; Maleckar, Mary M.; Koivumäki, Jussi T.; Dössel, Olaf; Seemann, Gunnar

    2013-01-01

    Mathematical modeling of cardiac electrophysiology is an insightful method to investigate the underlying mechanisms responsible for arrhythmias such as atrial fibrillation (AF). In past years, five models of human atrial electrophysiology with different formulations of ionic currents, and consequently diverging properties, have been published. The aim of this work is to give an overview of strengths and weaknesses of these models depending on the purpose and the general requirements of simulations. Therefore, these models were systematically benchmarked with respect to general mathematical properties and their ability to reproduce certain electrophysiological phenomena, such as action potential (AP) alternans. To assess the models' ability to replicate modified properties of human myocytes and tissue in cardiac disease, electrical remodeling in chronic atrial fibrillation (cAF) was chosen as test case. The healthy and remodeled model variants were compared with experimental results in single-cell, 1D and 2D tissue simulations to investigate AP and restitution properties, as well as the initiation of reentrant circuits. PMID:23316167

  3. Epidemiological profile of acute respiratory distress syndrome patients: A tertiary care experience

    PubMed Central

    Magazine, Rahul; Rao, Shobitha; Chogtu, Bharti; Venkateswaran, Ramkumar; Shahul, Hameed Aboobackar; Goneppanavar, Umesh

    2017-01-01

    Background: Acute respiratory distress syndrome (ARDS) is seen in critically ill patients. Its etiological spectrum in India is expected to be different from that seen in western countries due to the high prevalence of tropical infections. Aim: To study the epidemiological profile of ARDS patients. Setting: A tertiary care hospital in Karnataka, India. Materials and Methods: Retrospective analysis of 150 out of the 169 ARDS patients diagnosed during 2010–2012. Data collected included the clinical features and severity scoring parameters. Results: The mean age of the study population was 42.92 ± 13.91 years. The causes of ARDS included pneumonia (n = 35, 23.3%), scrub typhus (n = 33, 22%), leptospirosis (n = 11, 7.3%), malaria (n = 6, 4%), influenza (H1N1) (n = 10, 6.7%), pulmonary tuberculosis (n = 2, 1.3%), dengue (n = 1, 0.7%), abdominal sepsis (n = 16, 10.7%), skin infection (n = 3, 2%), unknown cause of sepsis (n = 18, 12%), and nonseptic causes (n = 15, 10%). A total of 77 (51.3%) patients survived, 66 (44%) expired, and 7 (4.7%) were discharged against medical advice (AMA). Preexisting comorbidities (46) were present in 13 survivors, 19 nonsurvivors, and four discharged AMA. History of surgery prior to the onset of ARDS was present in one survivor, 13 nonsurvivors, and one discharge AMA. Mean Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE III, and Sequential Organ Failure Assessment scores in survivors were 9.06 ± 4.3, 49.22 ± 14, and 6.43 ± 2.5 and in nonsurvivors 21.11 ± 7, 86.45 ± 23.5, and 10.6 ± 10, respectively. Conclusion: The most common cause of ARDS in our study was pneumonia, but a large percentage of cases were due to the tropical infections. Preexisting comorbidity, surgery prior to the onset of ARDS, higher severity scores, and organ failure scores were more frequently observed among nonsurvivors than survivors. PMID:28144059

  4. Invasive Candidiasis in Severe Acute Pancreatitis: Experience from a Tertiary Care Teaching Hospital

    PubMed Central

    Baronia, Arvind Kumar; Azim, Afzal; Ahmed, Armin; Gurjar, Mohan; Marak, Rungmei S. K.; Yadav, Reema; Sharma, Preeti

    2017-01-01

    Background: Invasive candidiasis (IC) is associated with increased morbidity in severe acute pancreatitis (SAP). There is limited information regarding the predisposing factors, Candida species distribution and in vitro susceptibility. Methodology: Current data have been derived from a larger prospective nonintervention study conducted on 200 critically ill patients which was done to study the antifungal prescription practices, collect epidemiological data, and perform an external validation of risk prediction models for IC under senior research associateship program of Council of Scientific and Industrial Research New Delhi. Of these critically ill patients, thirty had SAP and were included for analysis. Results: There were 23 males and 7 females. Out of eight patients (27%) who developed IC, three had isolated candidemia, two had isolated deep-seated candidiasis while three had both candidemia and deep-seated candidiasis. SAP patients with IC had a longer duration of Intensive Care Unit stay, hospital stay, days on mechanical ventilation and duration of shock. Mortality was not different between SAP patients with or without IC. Conclusion: There is a high rate of Candida infection in SAP. More studies are needed to generate epidemiological data and develop antifungal stewardship in this subset of high-risk population. PMID:28197050

  5. [Replantation and revascularization in acute upper limb amputation--the Sheba Medical Center experience].

    PubMed

    Oron, Amir; Yaffe, Batia

    2008-01-01

    Replantation and revascularization in acute upper-limb amputations are well-accepted surgical techniques in hand surgery. All medical staff members treating patients in emergency settings should be familiar with the indications, timetable, setup and transportation of patients rendered suitable for such surgery. While replantation surgery is not considered a simple surgical procedure by any means, viability rates approach ninety percent. The amputated part should be wrapped with gauze soaked in saline, placed in a sterile plastic bag and then put in an ice-filled container. The patient should be transferred to a medical center with a team dedicated to performing replantation procedures, following notification in advance. Time from the initial insult to the initiation of treatment should be minimized. Combined efforts employed by the primary caregivers and the microsurgical team will lead to optimization of patient treatment and improve the final outcome. During the years 1991-2007 a total of 383 upper limb replantation or revascularization procedures were performed at the Sheba Medical Center and are presented in this article.

  6. Reengineering acute episodic and chronic care delivery: the Geisinger Health System experience.

    PubMed

    Slotkin, Jonathan R; Casale, Alfred S; Steele, Glenn D; Toms, Steven A

    2012-07-01

    Comparative effectiveness research (CER) represents an evolution in clinical decision-making research that allows for the study of heterogeneous groups of patients with complex diseases processes. It has foundations in decision science, reliability science, and health care policy research. Health care finance will increasingly rely on CER for guidance in the coming years. There is increasing awareness of the importance of decreasing unwarranted variation in health care delivery. In the past 7 years, Geisinger Health System has performed broad reengineering of its acute episodic and chronic care delivery models utilizing macrosystem-level application of CER principles. These provider-driven process initiatives have resulted in significant improvement across all segments of care delivery, improved patient outcomes, and notable cost containment. These programs have led to the creation of novel pricing models, and when "hardwired" throughout a care delivery system, they can lead to correct medical decision making by 100% of providers in all patient encounters. Neurosurgery as a specialty faces unique challenges and opportunities with respect to broad adoption and application of CER techniques.

  7. Intravenous Lipid Emulsion Therapy for Acute Synthetic Cannabinoid Intoxication: Clinical Experience in Four Cases

    PubMed Central

    Aksel, Gökhan; Güneysel, Özlem; Taşyürek, Tanju; Kozan, Ergül; Çevik, Şebnem Eren

    2015-01-01

    There is no specific antidote for intoxication with synthetic cannabinoids. In this case series, we considered the efficiency of intravenous lipid emulsion therapy in four cases, who presented to emergency department with synthetic cannabinoid (bonzai) intoxication. The first patient had a GCS of 3 and a left bundle branch block on electrocardiography. The electrocardiography revealed sinus rhythm with normal QRS width after the treatment. The second patient had bradycardia, hypotension, and a GCS of 14. After intravenous lipid emulsion therapy, the bradycardia resolved, and the patient's GCS improved to 15. The third patient presented with a GCS of 8, and had hypotension and bradycardia. After the treatment, not only did the bradycardia resolve, but also the GCS improved to 15. The fourth patient, whose electrocardiography revealed accelerated junctional rhythm, had a GCS of 13. The patient's rhythm was sinus after the treatment. Cardiovascular recovery was seen in all four cases, and neurological recovery was also seen in three of them. Based on the fact that intravenous lipid emulsion is beneficial in patients intoxicated with lipophilic drugs, unstable patients presenting to the emergency department with acute synthetic cannabinoid intoxication may be candidates for intravenous lipid emulsion treatment. PMID:26078891

  8. Acute clinical onset chronic inflammatory demyelinating polyneuropathy in a dog.

    PubMed

    Molín, Jéssica; Márquez, Mercedes; Raurell, Xavier; Matiasek, Kaspar; Ferrer, Isidre; Pumarola, Martí

    2011-09-01

    We report a case of acute-onset ambulatory paraparesis with electrophysiological abnormalities compatible with axonal and demyelinating lesions in a Rottweiler dog. Although the clinical findings were compatible with acute canine idiopathic polyneuropathy, postmortem investigations revealed a chronic demyelinating polyneuropathy affecting the nerve roots. Due to the combination of acute clinical presentation and chronic pathologic features, this case is consistent with the acute-onset form of chronic inflammatory demyelinating polyneuropathy (A-CIDP).

  9. [Antiphlogisitc-rheologic infusion therapy of acute idiopathic facial paralysis. Experiences and results of 344 cases].

    PubMed

    Sittel, C; Stennert, E

    2000-08-01

    Antiphlogistic-rheologic infusion therapy is a widespread and well-established treatment modality for acute idiopathic facial paralysis (AIFP) in many German centers of otorhinolaryngology. However, there is still a lack of convincing data concerning this regimen's functional results and side effects. The medical records of 344 patients who were treated for AIFP between 1987 and 1997 were analyzed retrospectively. In 239 cases there was reliable information on functional outcome. Therapy consisted uniformly of intravenous infusion with prednisolone (250 mg initially, then tapering over 18 days) and simultaneous administration of dextran and pentoxifylline. From 239 patients with non-recurrent palsy having received treatment within 12 days after onset, 92.1% recovered completely without sequelae. In case of incomplete palsy (House-Brackmann grade II-V), normal facial function was restored in 97.7% of cases. Results were significantly better in the group in which therapy had been started within 3 days after onset of palsy. Adverse effects occurred rarely and were transient and mild in most cases. High-dose prednisolone in combination with low-molecular dextran and pentoxifylline for AIFP is a safe treatment modality leading to recovery rates superior to the most optimistic observations of the natural course of Bell's palsy. In the absence of a definitive controlled trial, the present study, although retrospective, is considered valid to show the effectiveness of our protocol. In the light of our data and of other publications, early treatment with corticosteroids in sufficient dosage seems appropriate, while therapeutic nihilism in AIFP does not seem justified.

  10. Total Arch versus Hemiarch Replacement for Type A Acute Aortic Dissection: A Single-Center Experience

    PubMed Central

    Nicolò, Francesca; Bovio, Emanuele; Serrao, Andrea; Zeitani, Jacob; Scafuri, Antonio; Chiariello, Luigi; Ruvolo, Giovanni

    2016-01-01

    We retrospectively evaluated early and intermediate outcomes of aortic arch surgery in patients with type A acute aortic dissection (AAD), investigating the effect of arch surgery extension on postoperative results. From January 2006 through July 2013, 201 patients with type A AAD underwent urgent corrective surgery at our institution. Of the 92 patients chosen for this study, 59 underwent hemiarch replacement (hemiarch group), and 33 underwent total arch replacement (total arch group) in conjunction with ascending aorta replacement. The operative mortality rate was 22%. Total arch replacement was associated with a 33% risk of operative death, versus 15% for hemiarch (P=0.044). Multivariable analysis found these independent predictors of operative death: age (odds ratio [OR]=1.13/yr; 95% confidence interval [CI], 1.04–1.23; P=0.002), body mass index >30 kg/m2 (OR=9.9; 95% CI, 1.28–19; P=0.028), postoperative low cardiac output (OR=10.6; 95% CI, 1.18–25; P=0.035), and total arch replacement (OR=8.8; 95% CI, 1.39–15; P=0.021) The mean overall 5-year survival rate was 59.3% ± 5.5%, and mean 5-year freedom from distal reintervention was 95.4% ± 3.2% (P=NS). In type A AAD, aortic arch surgery is still associated with high operative mortality rates; hemiarch replacement can be performed more safely than total arch replacement. Rates of distal aortic reoperation were not different between the 2 surgical strategies. PMID:28100966

  11. Sarin experiences in Japan: acute toxicity and long-term effects.

    PubMed

    Yanagisawa, N; Morita, H; Nakajima, T

    2006-11-01

    Two terrorist attacks with the nerve agent Sarin affected citizens in Matsumoto and Tokyo, Japan in 1994 and 1995, killing 19 and injuring more the 6000. Sarin, a very potent organophosphate nerve agent, inhibits acetylcholinesterase (AchE) activity within the central, peripheral, and autonomic nervous systems. Acute and long-term Sarin effects upon humans were well documented in these two events. Sarin gas inhalation caused instantaneous death by respiratory arrest in 4 victims in Matsumoto. In Tokyo, two died in station yards and another ten victims died in hospitals within a few hours to 3 months after poisoning. Six victims with serum ChE below 20% of the lowest normal were resuscitated from cardiopulmonary arrest (CPA) or coma with generalized convulsion. Five recovered completely and one remained in vegetative state due to anoxic brain damage. EEG abnormalities persisted for up to 5 years. Miosis and copious secretions from the respiratory and GI tracts (muscarinic effects) were common in severely to slightly affected victims. Weakness and twitches of muscles (nicotinic effects) appeared in severely affected victims. Neuropathy and ataxia were observed in small number (less than 10%) of victims, which findings disappeared between 3 days and 3 months. Leukocytosis and high serum CK levels were common. Hyperglycemia, ketonuria, low serum triglyceride, hypopotassemia were observed in severely affected victims, which abnormalities were attributed to damage of the adrenal medulla. Oximes, atropine sulphate, diazepam and ample intravenous infusion were effective treatments. Pralidoxime iodide IV reversed cholinesterase and symptoms quickly even if administered 6 h after exposure. Post Traumatic Stress Disorder (PTSD) was less than 8% after 5 years. However, psychological symptoms continue in victims of both incidents. In summary, both potent toxicity and quick recovery from critical ill conditions were prominent features. Conventional therapies proved effective in

  12. Acute kidney injury and mortality in hematopoietic stem cell transplantation: A single-center experience

    PubMed Central

    Sehgal, B.; George, P.; John, M. J.; Samuel, C.

    2017-01-01

    Hematopoietic stem cell transplant (HSCT) is a life-saving procedure for patients with several malignant and nonmalignant hematological disorders. Acute kidney injury (AKI) is a common complication after HSCT. The aim of the study was to identify the incidence and outcomes of AKI associated with HSCT in our center. Sixty-six HSCT recipients from October 2008 to March 2014 at Christian Medical College, Ludhiana, were followed up till July 31, 2014. RIFLE criteria utilizing serum creatinine was used to diagnose and stage AKI. Mortality and AKI were the primary outcomes studied. The risk of AKI in relation to conditioning regimen, type of HSCT (allogeneic and autologous), co-morbidities, graft versus host disease, drug toxicity, and veno-occlusive disease were analyzed. Sixty-five patients were included in the study. Male: Female ratio was 3.6:1 with a median age of 17 years (1.5–62). Forty-nine (75.4%) patients had AKI over 3 months, R 17 (26.2%), I 19 (29.2%), and F 13 (20%). AKI occurred at a mean of 19.4 ± 29.2 days after the HSCT. AKI was more commonly observed in patients undergoing allogeneic versus autologous HSCT (85.2% in allogeneic vs. 27.8% in autologous, P = 0.005). Mortality was seen in 20 patients (30.8%) in 3 months. AKI in the first 2 weeks (P < 0.016) was a significant risk factor for mortality. Incidence of AKI in HSCT is high and accounts for significant mortality and morbidity. RIFLE classification of AKI has prognostic significance among HSCT patients with an incremental trend in mortality. PMID:28182036

  13. Availability of on-site acute vascular interventional radiology techniques performed by trained acute care specialists: A single–emergency center experience

    PubMed Central

    Tsurukiri, Junya; Ohta, Shoichi; Mishima, Shiro; Homma, Hiroshi; Okumura, Eitaro; Akamine, Itsuro; Ueno, Masahito; Oda, Jun; Yukioka, Tetsuo

    2017-01-01

    INTRODUCTION Comprehensive treatment of a patient in acute medicine and surgery requires the use of both surgical techniques and other treatment methods. Recently, acute vascular interventional radiology techniques (AVIRTs) have become increasingly popular, enabling adequately trained in-house experts to improve the quality of on-site care. METHODS After obtaining approval from our institutional ethics committee, we conducted a retrospective study of AVIRT procedures performed by acute care specialists trained in acute medicine and surgery over a 1-year period, including those conducted out of hours. Trained acute care specialists were required to be certified by the Japanese Association of Acute Medicine and to have completed at least 1 year of training as a member of the endovascular team in the radiology department of another university hospital. The study was designed to ensure that at least one of the physicians was available to perform AVIRT within 1 h of a request at any time. Femoral sheath insertion was usually performed by the resident physicians under the guidance of trained acute care specialists. RESULTS The study sample comprised 77 endovascular procedures for therapeutic AVIRT (trauma, n = 29, and nontrauma, n = 48) among 62 patients (mean age, 64 years; range, 9–88 years), of which 55% were male. Of the procedures, 47% were performed out of hours (trauma, 52%; and nontrauma, 44%). Three patients underwent resuscitative endovascular balloon occlusion of the aorta in the emergency room. No major device-related complications were encountered, and the overall mortality rate within 60 days was 8%. The recorded causes of death included exsanguination (n = 2), pneumonia (n = 2), sepsis (n = 1), and brain death (n = 1). CONCLUSION When performed by trained acute care specialists, AVIRT seems to be advantageous for acute on-site care and provides good technical success. Therefore, a standard training program should be established for acute care specialists

  14. Pulsed linear acceleration as a vestibular stimulus in electrophysiological investigations.

    PubMed

    Jones, T A; Schiltz, T

    1989-03-01

    A simple method of generating precisely defined pulsed linear acceleration stimuli was developed and used to study vestibular responses to cranial acceleration. Electromechanical shakers were coupled to a stimulus platform. The platform, in turn, was used to couple stimuli to the skull. Movements were controlled by a voltage waveform (V(t] applied to shakers. Software algorithms were used to synthesize voltage functions (V(t]. The resulting acceleration was monitored [a(t)] and used to generate velocity [v(t)] and position [x(t)] functions (first and second integrals of a(t), respectively). The characteristics of stimuli used in physiological experiments are described. The system provides precise control of the timing and amplitude of acceleration, velocity and position pulses to the cranium and has proved to be valuable in developing noninvasive electrophysiological measures of peripheral and central vestibular function.

  15. Electrophysiological endophenotypes in rodent models of schizophrenia and psychosis

    PubMed Central

    Rosen, Andrew M.; Spellman, Timothy; Gordon, Joshua A.

    2015-01-01

    Schizophrenia is caused by a diverse array of risk factors, and results in a similarly diverse set of symptoms. Electrophysiological endophenotypes lie between risks and symptoms, and have the potential to link the two. Electrophysiological studies in rodent models, described here, demonstrate that widely differing risk factors result in a similar set of core electrophysiological endophenotypes, suggesting the possibility of a shared neurobiological substrate. PMID:25910423

  16. High-throughput electrophysiology with Xenopus oocytes

    PubMed Central

    Papke, Roger L.; Smith-Maxwell, Cathy

    2010-01-01

    Voltage-clamp techniques are typically used to study the plasma membrane proteins, such as ion channels and transporters that control bioelectrical signals. Many of these proteins have been cloned and can now be studied as potential targets for drug development. The two approaches most commonly used for heterologous expression of cloned ion channels and transporters involve either transfection of the genes into small cells grown in tissue culture or the injection of the genetic material into larger cells. The standard large cells used for the expression of cloned cDNA or synthetic RNA are the egg progenitor cells (oocytes) of the African frog, Xenopus laevis. Until recently, cellular electrophysiology was performed manually, one cell at a time by a single operator. However, methods of high-throughput electrophysiology have been developed which are automated and permit data acquisition and analysis from multiple cells in parallel. These methods are breaking a bottleneck in drug discovery, useful in some cases for primary screening as well as for thorough characterization of new drugs. Increasing throughput of high-quality functional data greatly augments the efficiency of academic research and pharmaceutical drug development. Some examples of studies that benefit most from high-throughput electrophysiology include pharmaceutical screening of targeted compound libraries, secondary screening of identified compounds for subtype selectivity, screening mutants of ligand-gated channels for changes in receptor function, scanning mutagenesis of protein segments, and mutant-cycle analysis. We describe here the main features and potential applications of OpusXpress, an efficient commercially available system for automated recording from Xenopus oocytes. We show some types of data that have been gathered by this system and review realized and potential applications. PMID:19149490

  17. Cell-Specific Cardiac Electrophysiology Models

    PubMed Central

    Groenendaal, Willemijn; Ortega, Francis A.; Kherlopian, Armen R.; Zygmunt, Andrew C.; Krogh-Madsen, Trine; Christini, David J.

    2015-01-01

    The traditional cardiac model-building paradigm involves constructing a composite model using data collected from many cells. Equations are derived for each relevant cellular component (e.g., ion channel, exchanger) independently. After the equations for all components are combined to form the composite model, a subset of parameters is tuned, often arbitrarily and by hand, until the model output matches a target objective, such as an action potential. Unfortunately, such models often fail to accurately simulate behavior that is dynamically dissimilar (e.g., arrhythmia) to the simple target objective to which the model was fit. In this study, we develop a new approach in which data are collected via a series of complex electrophysiology protocols from single cardiac myocytes and then used to tune model parameters via a parallel fitting method known as a genetic algorithm (GA). The dynamical complexity of the electrophysiological data, which can only be fit by an automated method such as a GA, leads to more accurately parameterized models that can simulate rich cardiac dynamics. The feasibility of the method is first validated computationally, after which it is used to develop models of isolated guinea pig ventricular myocytes that simulate the electrophysiological dynamics significantly better than does a standard guinea pig model. In addition to improving model fidelity generally, this approach can be used to generate a cell-specific model. By so doing, the approach may be useful in applications ranging from studying the implications of cell-to-cell variability to the prediction of intersubject differences in response to pharmacological treatment. PMID:25928268

  18. Comparative Toxicity Assessment of Nanosilver on Three Daphnia Species in Acute, Chronic and Multi-Generation Experiments

    PubMed Central

    Völker, Carolin; Boedicker, Cathinka; Daubenthaler, Jan; Oetken, Matthias; Oehlmann, Jörg

    2013-01-01

    The antibacterial properties of nanosilver have led to a versatile application spectrum including medical purposes and personal care products. However, the increasing use of nanosilver has raised concerns about its environmental impacts. Long-term exposure studies with aquatic invertebrates are essential to assess possible adverse effects on aquatic ecosystems. In the present study, acute (48 h), chronic (21 d) and long-term effects of nanosilver (primary size 15 nm) on five successive generations of three Daphnia species (D. magna, D. pulex, and D. galeata) were investigated. Acute EC50 values of nanosilver were 121 µg Ag L−1 for D. magna being the least sensitive species and 8.95 and 13.9 µg Ag L−1 for D. pulex and D. galeata, respectively. Chronic exposure provided EC10 values of 0.92 µg Ag L−1 for D. magna showing the most sensitive chronic reaction and 2.25 and 3.45 µg Ag L−1 for D. pulex and D. galeata, respectively. Comparative exposure to AgNO3 revealed a generally higher toxicity of the soluble form of silver. The multi-generation experiments resulted in effects on the population level for all tested species. Exposure of D. magna indicated an increased toxicity of nanosilver in the fifth generation of animals exposed to 10 µg Ag L−1. Neonates from pre-exposed parental daphnids did not completely recover when transferred into clean water. Exposure of D. pulex and D. galeata revealed not only increasing toxicity in some generations, but also greater tolerance to nanosilver. This study contributes to the assessment of the risk potential of nanosilver on aquatic ecosystems. It shows that effects of nanosilver vary within one genus and change with exposure duration. Therefore, long-term studies considering different aquatic species are needed to better understand the possible effects of nanosilver on aquatic ecosystems. PMID:24116021

  19. Comparative toxicity assessment of nanosilver on three Daphnia species in acute, chronic and multi-generation experiments.

    PubMed

    Völker, Carolin; Boedicker, Cathinka; Daubenthaler, Jan; Oetken, Matthias; Oehlmann, Jörg

    2013-01-01

    The antibacterial properties of nanosilver have led to a versatile application spectrum including medical purposes and personal care products. However, the increasing use of nanosilver has raised concerns about its environmental impacts. Long-term exposure studies with aquatic invertebrates are essential to assess possible adverse effects on aquatic ecosystems. In the present study, acute (48 h), chronic (21 d) and long-term effects of nanosilver (primary size 15 nm) on five successive generations of three Daphnia species (D. magna, D. pulex, and D. galeata) were investigated. Acute EC50 values of nanosilver were 121 µg Ag L(-1) for D. magna being the least sensitive species and 8.95 and 13.9 µg Ag L(-1) for D. pulex and D. galeata, respectively. Chronic exposure provided EC10 values of 0.92 µg Ag L(-1) for D. magna showing the most sensitive chronic reaction and 2.25 and 3.45 µg Ag L(-1) for D. pulex and D. galeata, respectively. Comparative exposure to AgNO3 revealed a generally higher toxicity of the soluble form of silver. The multi-generation experiments resulted in effects on the population level for all tested species. Exposure of D. magna indicated an increased toxicity of nanosilver in the fifth generation of animals exposed to 10 µg Ag L(-1). Neonates from pre-exposed parental daphnids did not completely recover when transferred into clean water. Exposure of D. pulex and D. galeata revealed not only increasing toxicity in some generations, but also greater tolerance to nanosilver. This study contributes to the assessment of the risk potential of nanosilver on aquatic ecosystems. It shows that effects of nanosilver vary within one genus and change with exposure duration. Therefore, long-term studies considering different aquatic species are needed to better understand the possible effects of nanosilver on aquatic ecosystems.

  20. Opportunities and challenges of current electrophysiology research: a plea to establish 'translational electrophysiology' curricula.

    PubMed

    Lau, Dennis H; Volders, Paul G A; Kohl, Peter; Prinzen, Frits W; Zaza, Antonio; Kääb, Stefan; Oto, Ali; Schotten, Ulrich

    2015-05-01

    Cardiac electrophysiology has evolved into an important subspecialty in cardiovascular medicine. This is in part due to the significant advances made in our understanding and treatment of heart rhythm disorders following more than a century of scientific discoveries and research. More recently, the rapid development of technology in cellular electrophysiology, molecular biology, genetics, computer modelling, and imaging have led to the exponential growth of knowledge in basic cardiac electrophysiology. The paradigm of evidence-based medicine has led to a more comprehensive decision-making process and most likely to improved outcomes in many patients. However, implementing relevant basic research knowledge in a system of evidence-based medicine appears to be challenging. Furthermore, the current economic climate and the restricted nature of research funding call for improved efficiency of translation from basic discoveries to healthcare delivery. Here, we aim to (i) appraise the broad challenges of translational research in cardiac electrophysiology, (ii) highlight the need for improved strategies in the training of translational electrophysiologists, and (iii) discuss steps towards building a favourable translational research environment and culture.

  1. Acute pain experience in individuals with autism spectrum disorders: a review.

    PubMed

    Moore, David J

    2015-05-01

    In addition to the diagnostic criteria for autism spectrum disorder, a number of clinically important comorbid complaints, including sensory abnormalities, are also discussed. One difference often noted in these accounts is hyposensitivity to pain; however, evidence for this is limited. The purpose of the current review therefore was to examine sensitivity to pain of individuals with autism spectrum disorder. This review is interested in reports which consider differences in subjective experience of pain (i.e. different pain thresholds) and differences in behavioural response to pain (i.e. signs of pain-related distress). Studies were included if they were conducted with human subjects, included a clearly diagnosed autism spectrum disorder population and reported data pertaining to pain experience relative to the neurotypical population. Studies were classified as being self/parent report, clinical observations, observations of response to medical procedures or experimental examination of pain. Both self/parent report and clinical observations appeared to report hyposensitivity to pain, whereas observations of medical procedures and experimental manipulation suggested normal or hypersensitive responses to pain. This review suggests that contrary to classical reports, individuals with autism spectrum disorder do not appear to have systematically altered pain responses or thresholds. More systematic experimental examination of this area is needed to understand responses to pain of individuals with autism spectrum disorder.

  2. Electrophysiological consequences of KATP Gain-of-function in the heart: Conduction abnormalities in Cantu Syndrome

    PubMed Central

    Levin, Mark D.; Zhang, Haixia; Uchida, Keita; Grange, Dorothy K.; Singh, Gautam K.; Nichols, Colin G.

    2015-01-01

    Background Gain-of-function (GOF) mutations in the KATP channel subunits Kir6.1 and SUR2 cause Cantu syndrome (CS), a disease characterized by multiple cardiovascular abnormalities. Objective To better understand the electrophysiological consequences of such GOF mutations in the heart. Methods We generated transgenic mice (Kir6.1-GOF) expressing ATP-insensitive Kir6.1[G343D] subunits under α-myosin heavy chain (α-MHC) promoter control, to target gene expression specifically in cardiomyocytes, and carried out patch-clamp experiments on isolated ventricular myocytes, invasive electrophysiology on anesthetized mice. Results In Kir6.1-GOF ventricular myocytes, KATP channels show decreased ATP sensitivity, but there is no significant change in current density. Ambulatory ECG recordings on Kir6.1-GOF mice reveal AV nodal conduction abnormalities and junctional rhythm. Invasive electrophysiological analyses reveal slowing of conduction and conduction failure through the AV node, but no increase in susceptibility to atrial or ventricular ectopic activity. Surface electrocardiograms recorded from CS patients also demonstrate first degree AV block, and fascicular block. Conclusions The primary electrophysiological consequence of cardiac KATP GOF is on the conduction system, particularly the AV node, resulting in conduction abnormalities in CS patients, who carry KATP GOF mutations. PMID:26142302

  3. Effects of bepridil on cardiac electrophysiologic properties.

    PubMed

    Prystowsky, E N

    1992-04-09

    The current classification system for antiarrhythmic drugs has several shortcomings; for example, electrophysiologic effects are defined in normal tissue, whereas antiarrhythmic drugs are often used clinically in diseased or injured tissue. Consideration of the electrophysiologic effects of bepridil in humans emphasizes the drawbacks of the classification system. Bepridil is primarily a calcium antagonist with class IV action. However, because the drug has class IA action as well, it should not be considered a typical class I or class IV agent. Bepridil has been observed to prolong the QT interval in the majority of patients in whom it is used for treatment of angina. However, in US clinical trials, including open extensions, only 7 cases of torsades de pointes have been recorded. In France, where the drug is approved for treatment of angina, the incidence of torsades de pointes was 0.01% in 1989. No consensus currently exists regarding what degree of QT prolongation constitutes increased risk for a ventricular proarrhythmic event. Based on current information, bepridil should be used cautiously in patients with a propensity toward hypokalemia, which can exacerbate or induce a proarrhythmic state. The drug should not be used in patients with a prolonged QT interval at baseline, a history of torsades de pointes, or long QT interval syndrome. Bepridil also should be avoided in patients with sinus node dysfunction or second- or third-degree atrioventricular block.

  4. Electrophysiology of autonomic neuromuscular transmission involving ATP.

    PubMed

    Sneddon, P

    2000-07-03

    Electrophysiological investigations of autonomic neuromuscular transmission have provided great insights into the role of ATP as a neurotransmitter. Burnstock and Holman made the first recordings of excitatory junction potentials (e.j.p.s) produced by sympathetic nerves innervating the smooth muscle of the guinea-pig vas deferens. This led to the identification of ATP as the mediator of e.j.p.s in this tissue, where ATP acts as a cotransmitter with noradrenaline. The e.j.p.s are mediated solely by ATP acting on P2X(1) receptors leading to action potentials and a rapid phasic contraction, whilst noradrenaline mediates a slower, tonic contraction which is not dependent on membrane depolarisation. Subsequent electrophysiological studies of the autonomic innervation of smooth muscles of the urogenital, gastrointestinal and cardiovascular systems have revealed a similar pattern of response, where ATP mediates a fast electrical and mechanical response, whilst another transmitter such as noradrenaline, acetylcholine, nitric oxide or a peptide mediates a slower response. The modulation of junction potentials by a variety of pre-junctional receptors and the mechanism of inactivation of ATP as a neurotransmitter will also be described.

  5. Relationships between cortical myeloarchitecture and electrophysiological networks

    PubMed Central

    Hunt, Benjamin A. E.; Tewarie, Prejaas K.; Mougin, Olivier E.; Geades, Nicolas; Singh, Krish D.; Morris, Peter G.; Gowland, Penny A.; Brookes, Matthew J.

    2016-01-01

    The human brain relies upon the dynamic formation and dissolution of a hierarchy of functional networks to support ongoing cognition. However, how functional connectivities underlying such networks are supported by cortical microstructure remains poorly understood. Recent animal work has demonstrated that electrical activity promotes myelination. Inspired by this, we test a hypothesis that gray-matter myelin is related to electrophysiological connectivity. Using ultra-high field MRI and the principle of structural covariance, we derive a structural network showing how myelin density differs across cortical regions and how separate regions can exhibit similar myeloarchitecture. Building upon recent evidence that neural oscillations mediate connectivity, we use magnetoencephalography to elucidate networks that represent the major electrophysiological pathways of communication in the brain. Finally, we show that a significant relationship exists between our functional and structural networks; this relationship differs as a function of neural oscillatory frequency and becomes stronger when integrating oscillations over frequency bands. Our study sheds light on the way in which cortical microstructure supports functional networks. Further, it paves the way for future investigations of the gray-matter structure/function relationship and its breakdown in pathology. PMID:27830650

  6. Effect of mental stress on dynamic electrophysiological properties of the endocardium and epicardium in humans

    PubMed Central

    Finlay, Malcolm C.; Lambiase, Pier D.; Ben-Simon, Ron; Taggart, Peter

    2016-01-01

    Background Striking temporal associations exist between ventricular arrhythmia and acute mental stress, for example, during natural disasters, or defibrillator shocks associated with stressful events. We hypothesized that electrophysiological changes in response to mental stress may be exaggerated at short coupling intervals and hence relevant to arrhythmia initiation. Objective The aim of this study was to determine the dynamic response in human electrophysiology during mental stress. Methods Patients with normal hearts and supraventricular tachycardia underwent electrophysiological studies avoiding sedation. Conditions of relaxation and stress were induced with standardized psychometric protocols (mental arithmetic and anger recall) during decremental S1S2 right ventricular (RV) pacing. Unipolar electrograms were acquired simultaneously from the RV endocardium, left ventricular (LV) endocardium (LV endo), and epicardium (LV epi), and activation-recovery intervals (ARIs) computed. Results Twelve patients ( 9 women; median age 34 years) were studied. During stress, effective refractory period (ERP) reduced from 228 ± 23 to 221 ± 21 ms (P < .001). ARIs reduced during mental stress (P < .001), with greater reductions in LV endocardium than in the epicardium or RV endocardium (LV endo −8 ms; LV epi −5 ms; RV endo −4 ms; P < .001). Mental stress depressed the entire electrical restitution curve, with minimal effect on slope. A substantial reduction in minimal ARIs on the restitution curve in LV endo occurred, commensurate with the reduction in ERP (LV endo ARI 195 ± 31 ms at rest to 182 ± 32 ms during mental stress; P < .001). Dispersion of repolarization increased sharply at coupling intervals approaching ERP during stress but not at rest. Conclusion Mental stress induces significant electrophysiological changes. The increase in dispersion of repolarization at short coupling intervals may be relevant to observed phenomena of arousal-associated arrhythmia

  7. Cellular cardiac electrophysiology modeling with Chaste and CellML.

    PubMed

    Cooper, Jonathan; Spiteri, Raymond J; Mirams, Gary R

    2014-01-01

    Chaste is an open-source C++ library for computational biology that has well-developed cardiac electrophysiology tissue simulation support. In this paper, we introduce the features available for performing cardiac electrophysiology action potential simulations using a wide range of models from the Physiome repository. The mathematics of the models are described in CellML, with units for all quantities. The primary idea is that the model is defined in one place (the CellML file), and all model code is auto-generated at compile or run time; it never has to be manually edited. We use ontological annotation to identify model variables describing certain biological quantities (membrane voltage, capacitance, etc.) to allow us to import any relevant CellML models into the Chaste framework in consistent units and to interact with them via consistent interfaces. This approach provides a great deal of flexibility for analysing different models of the same system. Chaste provides a wide choice of numerical methods for solving the ordinary differential equations that describe the models. Fixed-timestep explicit and implicit solvers are provided, as discussed in previous work. Here we introduce the Rush-Larsen and Generalized Rush-Larsen integration techniques, made available via symbolic manipulation of the model equations, which are automatically rearranged into the forms required by these approaches. We have also integrated the CVODE solvers, a 'gold standard' for stiff systems, and we have developed support for symbolic computation of the Jacobian matrix, yielding further increases in the performance and accuracy of CVODE. We discuss some of the technical details of this work and compare the performance of the available numerical methods. Finally, we discuss how this is generalized in our functional curation framework, which uses a domain-specific language for defining complex experiments as a basis for comparison of model behavior.

  8. Real-time in vivo optogenetic neuromodulation and multielectrode electrophysiologic recording with NeuroRighter

    PubMed Central

    Laxpati, Nealen G.; Mahmoudi, Babak; Gutekunst, Claire-Anne; Newman, Jonathan P.; Zeller-Townson, Riley; Gross, Robert E.

    2014-01-01

    Optogenetic channels have greatly expanded neuroscience’s experimental capabilities, enabling precise genetic targeting and manipulation of neuron subpopulations in awake and behaving animals. However, many barriers to entry remain for this technology – including low-cost and effective hardware for combined optical stimulation and electrophysiologic recording. To address this, we adapted the open-source NeuroRighter multichannel electrophysiology platform for use in awake and behaving rodents in both open and closed-loop stimulation experiments. Here, we present these cost-effective adaptations, including commercially available LED light sources; custom-made optical ferrules; 3D printed ferrule hardware and software to calibrate and standardize output intensity; and modifications to commercially available electrode arrays enabling stimulation proximally and distally to the recording target. We then demonstrate the capabilities and versatility of these adaptations in several open and closed-loop experiments, demonstrate spectrographic methods of analyzing the results, as well as discuss artifacts of stimulation. PMID:25404915

  9. t(8;21) (q22;q22) acute myelogenous leukemia in Mexico: a single institution experience.

    PubMed

    Ruiz-Argüelles, Guillermo J; Morales-Toquero, Amelia; Manzano, Carlos; Ruiz-Delgado, Guillermo J; Jaramillo, Patricia; Gonzalez-Carrillo, Martha L; Reyes-Núñez, Virginia

    2006-08-01

    We analyze the prevalence and clinical features of a group of patients with t(8;21) (q22;q22) acute myeloblastic leukemia, identified in a single institution in México over a 10-year period. Fifteen patients presented at the Centro de Hematología y Medicina Interna de Puebla from February 1995 to August 2005; only nine were treated and followed in the institution. Median age was 24 years, (range 7-49); there was only one male. According to the French-American-British (FAB) morphological classification of leukemia, the morphology was M2 in four cases, M4 in three cases, M3 in one case and M0 in one. In addition to the myeloid markers, lymphoid markers were identified in 6 patients. Patients were induced to remission with combined chemotherapy and three subsequently underwent bone marrow transplantation (BMT). The median overall and disease-free survival has not been reached, being above 3390 days, the probability of survival at this time was 73%. In this single-center experience in México, we found that the t(8;21) (q22;q22) variant of leukemia was more frequent than in Caucasian populations, that the co-expression of lymphoid markers in the blast cells is very frequent and that this malignancy is associated with a relatively good prognosis.

  10. Electrophysiological comparison between males and females in HNPP.

    PubMed

    Manganelli, Fiore; Pisciotta, Chiara; Dubbioso, Raffaele; Maruotti, Valerio; Iodice, Rosa; Notturno, Francesca; Ruggiero, Lucia; Vitale, Carmine; Nolano, Maria; Uncini, Antonino; Santoro, Lucio

    2013-08-01

    Some evidences highlighted a higher clinical expression of hereditary neuropathy with liability to pressure palsy (HNPP) in males, and a higher load of traumatic nerve injuries due to different occupational activity has been invoked to explain this observation. It is unknown whether this increased clinical impairment corresponds to a greater electrophysiological involvement. Thus, we compared clinical and electrophysiological features between men and women in a large cohort of HNPP patients. Nerve palsies and electrophysiological abnormalities were more frequent in men, and electrophysiological findings which differentiated males from females did not show any age-related worsening. In conclusion, our findings showed a higher clinical and electrophysiological involvement in males which does not seem related to different cumulative nerve damage over time. We believe that the higher disease expression may increase the chance to detect the disease in males and, thereby, to underestimate the HNPP diagnosis in females.

  11. Quantum dot-based multiphoton fluorescent pipettes for targeted neuronal electrophysiology

    PubMed Central

    Huber, Daniel; Barbic, Mladen; Macklin, John J.; Susumu, Kimihiro; Delehanty, James B.; Huston, Alan L.; Makara, Judit K.; Medintz, Igor L.

    2014-01-01

    Targeting visually-identified neurons for electrophysiological recording is a fundamental neuroscience technique; however, its potential is hampered by poor visualization of pipette tips in deep brain tissue. We describe a technique whereby quantum dots coat glass pipettes providing strong two-photon contrast at deeper penetration depths than current methods. We demonstrate utility in targeted patch-clamp recording experiments and single cell electroporation from identified rat and mouse neurons in vitro and in vivo. PMID:25326662

  12. Effect of chromium (VI) exposure on antioxidant defense status and trace element homeostasis in acute experiment in rat.

    PubMed

    Kotyzová, Dana; Hodková, Anna; Bludovská, Monika; Eybl, Vladislav

    2015-11-01

    Occupational exposure to hexavalent chromium (Cr(VI)) compounds is of concern in many Cr-related industries and their surrounding environment. Cr(VI) is a proven toxin and carcinogen. The Cr(VI) compounds are easily absorbed, can diffuse across cell membranes, and have strong oxidative potential. Despite intensive studies of Cr(VI) pro-oxidative effects, limited data exist on the influence of Cr(VI) on selenoenzymes thioredoxin reductase (TrxR) and glutathione peroxidase (GPx)-important components of antioxidant defense system. This study investigates the effect of Cr(VI) exposure on antioxidant defense status, with focus on these selenoenzymes, and on trace element homeostasis in an acute experiment in rat. Male Wistar rats (130-140g) were assigned to two groups of 8 animals: I. control; and II. Cr(VI) treated. The animals in Cr(VI) group were administered a single dose of K2Cr2O7 (20 mg /kg, intraperitoneally (ip)). The control group received saline solution. After 24 h, the animals were sacrificed and the liver and kidneys were examined for lipid peroxidation (LP; thiobarbituric acid reactive substances (TBARS) concentration), the level of reduced glutathione (GSH) and the activities of GPx-1, TrxR-1, and glutathione reductase (GR). Samples of tissues were also used to estimate Cr accumulation and alterations in zinc, copper, and iron levels. The acute Cr(VI) exposure caused an increase in both hepatic and renal LP (by 70%, p < 0.01 and by 15%, p < 0.05, respectively), increased hepatic GSH level and GPx-1 activity, and decreased renal GPx-1 activity. The activity of GR was not changed. A significant inhibitory effect of Cr(VI) was found on TrxR-1 activity in both the liver and the kidneys. The ability of Cr(VI) to cause TrxR inhibition could contribute to its cytotoxic effects. Further investigation of oxidative responses in different in vivo models may enable the development of strategies to protect against Cr(VI) oxidative damage.

  13. Stimfit: quantifying electrophysiological data with Python

    PubMed Central

    Guzman, Segundo J.; Schlögl, Alois; Schmidt-Hieber, Christoph

    2013-01-01

    Intracellular electrophysiological recordings provide crucial insights into elementary neuronal signals such as action potentials and synaptic currents. Analyzing and interpreting these signals is essential for a quantitative understanding of neuronal information processing, and requires both fast data visualization and ready access to complex analysis routines. To achieve this goal, we have developed Stimfit, a free software package for cellular neurophysiology with a Python scripting interface and a built-in Python shell. The program supports most standard file formats for cellular neurophysiology and other biomedical signals through the Biosig library. To quantify and interpret the activity of single neurons and communication between neurons, the program includes algorithms to characterize the kinetics of presynaptic action potentials and postsynaptic currents, estimate latencies between pre- and postsynaptic events, and detect spontaneously occurring events. We validate and benchmark these algorithms, give estimation errors, and provide sample use cases, showing that Stimfit represents an efficient, accessible and extensible way to accurately analyze and interpret neuronal signals. PMID:24600389

  14. Rheumatoid neuropathy: a histological and electrophysiological study

    PubMed Central

    Weller, R. O.; Bruckner, F. E.; Chamberlain, M. Anne

    1970-01-01

    Peripheral nerves in five patients with rheumatoid neuropathy were examined electrophysiologically and by sural nerve biopsy. There was close correlation between the clinical severity of the disease and the degree of nerve damage found histologically and by EMG. Group 1 patients with a mild distal sensory neuropathy showed varying degrees of axonal degeneration in the large myelinated fibres and some segmental demyelination. Group 2 patients with a severe, rapidly progressive sensori-motor neuropathy had extensive loss of myelinated fibres. In one case all the large fibres had degenerated. The second case had lost both large and small myelinated fibres together with many of the non-myelinated axons. The major nerve damage in both groups appeared to be axonal degeneration but some segmental demyelination was detected. Occlusive vascular disease in the vasa nervorum was considered to be the major cause of the nerve damage. Images PMID:4320255

  15. Lyme carditis. Electrophysiologic and histopathologic study

    SciTech Connect

    Reznick, J.W.; Braunstein, D.B.; Walsh, R.L.; Smith, C.R.; Wolfson, P.M.; Gierke, L.W.; Gorelkin, L.; Chandler, F.W.

    1986-11-01

    To further define the nature of Lyme carditis, electrophysiologic study and endomyocardial biopsy were performed in a patient with Lyme disease, whose principal cardiac manifestation was high-degree atrioventricular block. Intracardiac recording demonstrated supra-Hisian block and complete absence of an escape mechanism. Gallium 67 scanning demonstrated myocardial uptake, and right ventricular endomyocardial biopsy revealed active lymphocytic myocarditis. A structure compatible with a spirochetal organism was demonstrated in one biopsy specimen. It is concluded that Lyme disease can produce active myocarditis, as suggested by gallium 67 imaging and confirmed by endomyocardial biopsy. Furthermore, the presence of high-grade atrioventricular block in this disease requires aggressive management with temporary pacemaker and corticosteroid therapy.

  16. Electrophysiological characterization of human rectal afferents

    PubMed Central

    Ng, Kheng-Seong; Brookes, Simon J.; Montes-Adrian, Noemi A.; Mahns, David A.

    2016-01-01

    It is presumed that extrinsic afferent nerves link the rectum to the central nervous system. However, the anatomical/functional existence of such nerves has never previously been demonstrated in humans. Therefore, we aimed to identify and make electrophysiological recordings in vitro from extrinsic afferents, comparing human rectum to colon. Sections of normal rectum and colon were procured from anterior resection and right hemicolectomy specimens, respectively. Sections were pinned and extrinsic nerves dissected. Extracellular visceral afferent nerve activity was recorded. Neuronal responses to chemical [capsaicin and “inflammatory soup” (IS)] and mechanical (Von Frey probing) stimuli were recorded and quantified as peak firing rate (range) in 1-s intervals. Twenty-eight separate nerve trunks from eight rectums were studied. Of these, spontaneous multiunit afferent activity was recorded in 24 nerves. Peak firing rates increased significantly following capsaicin [median 6 (range 3–25) spikes/s vs. 2 (1–4), P < 0.001] and IS [median 5 (range 2–18) spikes/s vs. 2 (1–4), P < 0.001]. Mechanosensitive “hot spots” were identified in 16 nerves [median threshold 2.0 g (range 1.4–6.0 g)]. In eight of these, the threshold decreased after IS [1.0 g (0.4–1.4 g)]. By comparison, spontaneous activity was recorded in only 3/30 nerves studied from 10 colons, and only one hot spot (threshold 60 g) was identified. This study confirms the anatomical/functional existence of extrinsic rectal afferent nerves and characterizes their chemo- and mechanosensitivity for the first time in humans. They have different electrophysiological properties to colonic afferents and warrant further investigation in disease states. PMID:27789454

  17. Electrophysiological correlates of voice learning and recognition.

    PubMed

    Zäske, Romi; Volberg, Gregor; Kovács, Gyula; Schweinberger, Stefan Robert

    2014-08-13

    Listeners can recognize familiar human voices from variable utterances, suggesting the acquisition of speech-invariant voice representations during familiarization. However, the neurocognitive mechanisms mediating learning and recognition of voices from natural speech are currently unknown. Using electrophysiology, we investigated how representations are formed during intentional learning of initially unfamiliar voices that were later recognized among novel voices. To probe the acquisition of speech-invariant voice representations, we compared a "same sentence" condition, in which speakers repeated the study utterances at test, and a "different sentence" condition. Although recognition performance was higher for same compared with different sentences, substantial voice learning also occurred for different sentences, with recognition performance increasing across consecutive study-test-cycles. During study, event-related potentials elicited by voices subsequently remembered elicited a larger sustained parietal positivity (∼250-1400 ms) compared with subsequently forgotten voices. This difference due to memory was unaffected by test sentence condition and may thus reflect the acquisition of speech-invariant voice representations. At test, voices correctly classified as "old" elicited a larger late positive component (300-700 ms) at Pz than voices correctly classified as "new." This event-related potential OLD/NEW effect was limited to the same sentence condition and may thus reflect speech-dependent retrieval of voices from episodic memory. Importantly, a speech-independent effect for learned compared with novel voices was found in beta band oscillations (16-17 Hz) between 290 and 370 ms at central and right temporal sites. Our results are a first step toward elucidating the electrophysiological correlates of voice learning and recognition.

  18. Hemodynamic and Electrophysiological Relationship Involved in Human Face Processing: Evidence from a Combined fMRI-ERP Study

    ERIC Educational Resources Information Center

    Iidaka, Tetsuya; Matsumoto, Atsushi; Haneda, Kaoruko; Okada, Tomohisa; Sadato, Norihiro

    2006-01-01

    Functional magnetic resonance imaging (fMRI) and event-related potential (ERP) experiments were conducted in the same group of subjects and with an identical task paradigm to investigate a possible relationship between hemodynamic and electrophysiological responses within the brain. The subjects were instructed to judge whether visually presented…

  19. The Electrophysiological Phenomenon of Alzheimer's Disease: A Psychopathology Theory.

    PubMed

    Holston, Ezra C

    2015-08-01

    The current understanding of Alzheimer's disease (AD) is based on the Aβ and tau pathology and the resulting neuropathological changes, which are associated with manifested clinical symptoms. However, electrophysiological brain changes may provide a more expansive understanding of AD. Hence, the objective of this systematic review is to propose a theory about the electrophysiological phenomenon of Alzheimer's disease (EPAD). The review of literature resulted from an extensive search of PubMed and MEDLINE databases. One-hundred articles were purposively selected. They provided an understanding of the concepts establishing the theory of EPAD (neuropathological changes, neurochemical changes, metabolic changes, and electrophysiological brain changes). Changes in the electrophysiology of the brain are foundational to the association or interaction of the concepts. Building on Berger's Psychophysical Model, it is evident that electrophysiological brain changes occur and affect cortical areas to generate or manifest symptoms from onset and across the stages of AD, which may be prior to pathological changes. Therefore, the interaction of the concepts demonstrates how the psychopathology results from affected electrophysiology of the brain. The theory of the EPAD provides a theoretical foundation for appropriate measurements of AD without dependence on neuropathological changes. Future research is warranted to further test this theory. Ultimately, this theory contributes to existing knowledge because it shows how electrophysiological changes are useful in understanding the risk and progression of AD across the stages.

  20. A recording chamber for small volume slice electrophysiology

    PubMed Central

    Quinn, Kevin D.; Cruickshank-Quinn, Charmion I.; Reisdorph, Nichole; Lei, Tim C.; Klug, Achim

    2015-01-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products. PMID:26203105

  1. A recording chamber for small volume slice electrophysiology.

    PubMed

    Dondzillo, Anna; Quinn, Kevin D; Cruickshank-Quinn, Charmion I; Reisdorph, Nichole; Lei, Tim C; Klug, Achim

    2015-09-01

    Electrophysiological recordings from brain slices are typically performed in small recording chambers that allow for the superfusion of the tissue with artificial extracellular solution (ECS), while the chamber holding the tissue is mounted in the optical path of a microscope to image neurons in the tissue. ECS itself is inexpensive, and thus superfusion rates and volumes of ECS consumed during an experiment using standard ECS are not critical. However, some experiments require the addition of expensive pharmacological agents or other chemical compounds to the ECS, creating a need to build superfusion systems that operate on small volumes while still delivering appropriate amounts of oxygen and other nutrients to the tissue. We developed a closed circulation tissue chamber for slice recordings that operates with small volumes of bath solution in the range of 1.0 to 2.6 ml and a constant oxygen/carbon dioxide delivery to the solution in the bath. In our chamber, the ECS is oxygenated and recirculated directly in the recording chamber, eliminating the need for tubes and external bottles/containers to recirculate and bubble ECS and greatly reducing the total ECS volume required for superfusion. At the same time, the efficiency of tissue oxygenation and health of the section are comparable to standard superfusion methods. We also determined that the small volume of ECS contains a sufficient amount of nutrients to support the health of a standard brain slice for several hours without concern for either depletion of nutrients or accumulation of waste products.

  2. Empathic responses to others' gains and losses: an electrophysiological investigation.

    PubMed

    Ma, Qingguo; Shen, Qiang; Xu, Qing; Li, Diandian; Shu, Liangchao; Weber, Bernd

    2011-02-01

    A growing number of studies in exploring empathic modulation have revealed the neural substrates of how social stimuli are represented in the human brain, especially the pain of others. The empathic response of observing other's gains and losses, however, remains not clearly characterized. In the current study, we carried out two experiments with a gamble task to investigate how the effects of interpersonal familiarity and self-participation work on modulating the temporal neural response towards gain and loss of a friend or a stranger using scalp-recorded event-related potentials (ERPs). The electrophysiological data show an increased amplitude of the P300 when observing a friend's performance compared to strangers playing the game in both two experiments. But the distinction of differentiated feedback-related negativity (d-FRN) between friends and strangers was only observed when the player was not involved in the game. These results indicated that the participants exerted more motivational relevance toward their friends than strangers, but the participants' empathic response toward friends was only salient when they were not involved in the gamble directly. Therefore, both familiarity and self-engagement are factors that influence the empathy towards others, complementing the recent research on empathic modulation.

  3. Electrophysiological effects of L 9394 (benzoyl-indolizine) in man.

    PubMed Central

    Waleffe, A; Bordalo, A; Bruninx, P; Wellens, H J; Kulbertus, H E

    1979-01-01

    The electrophysiological effects of L 9394 (benzoyl-indolizine), a substance chemically related to amiodarone, but devoid of iodine atoms, were investigated by programmed electrical stimulation of the heart in 12 patients with various forms of tachycardia. Four subjects had electrocardiographic evidence of the WPW syndrome and episodes of circus movement tachycardia. Paroxysmal supraventricular tachycardia, confined to the atrioventricular (AV) node, was found in 3 patients. In 2 cases, where a short PR interval was present, the main complaint was the occurrence of paroxysmal atrial fibrillation. In the remaining 3 instances, the arrhythmia consisted of slow ventricular tachycardia (1 case), supraventricular tachycardia of the focal type (1 case), and episodes of primary ventricular fibrillation, not related to acute myocardial ischaemia (1 case). L 9394 injected intravenously was seen to lengthen the transnodal conduction time as well as the effective and functional refractory periods of the node. Similar effects were found on the retrograde VA pathway. The drug had no action on the infra-Hisian conduction system, on the refractory periods of ventricular muscle, or on the refractory periods of accessory bypasses. The drug was injected during an episode of tachycardia in 6 cases with reproducible supraventricular re-entrant tachycardia. Three had a tachycardia circuit confined to the node. In those instances, the drug had beneficial effects (slowing and interruption of tachycardia, decrease or abolition of echo zone; loss of ability to induce tachycardia). In the other 3 cases, an accessory pathway was incorporated in the circuit. L 9394 interrupted the tachycardia in 2 instances (by anterograde AV block), but failed to protect all 3 patients against reinitiation of tachycardia by premature stimuli. It is concluded that L9394 does not share all the pharmacological properties of amiodarone and will not replace it in all its indications. Images PMID:426960

  4. Large-scale, high-resolution electrophysiological imaging of field potentials in brain slices with microelectronic multielectrode arrays

    PubMed Central

    Ferrea, E.; Maccione, A.; Medrihan, L.; Nieus, T.; Ghezzi, D.; Baldelli, P.; Benfenati, F.; Berdondini, L.

    2012-01-01

    Multielectrode arrays (MEAs) are extensively used for electrophysiological studies on brain slices, but the spatial resolution and field of recording of conventional arrays are limited by the low number of electrodes available. Here, we present a large-scale array recording simultaneously from 4096 electrodes used to study propagating spontaneous and evoked network activity in acute murine cortico-hippocampal brain slices at unprecedented spatial and temporal resolution. We demonstrate that multiple chemically induced epileptiform episodes in the mouse cortex and hippocampus can be classified according to their spatio-temporal dynamics. Additionally, the large-scale and high-density features of our recording system enable the topological localization and quantification of the effects of antiepileptic drugs in local neuronal microcircuits, based on the distinct field potential propagation patterns. This novel high-resolution approach paves the way to detailed electrophysiological studies in brain circuits spanning spatial scales from single neurons up to the entire slice network. PMID:23162432

  5. Electrophysiological effects of semantic context in picture and word naming.

    PubMed

    Janssen, Niels; Carreiras, Manuel; Barber, Horacio A

    2011-08-01

    Recent language production studies have started to use electrophysiological measures to investigate the time course of word selection processes. An important contribution with respect to this issue comes from studies that have relied on an effect of semantic context in the semantic blocking task. Here we used this task to further establish the empirical pattern associated with the effect of semantic context, and whether the effect arises during output processing. Electrophysiological and reaction time measures were co-registered while participants overtly named picture and word stimuli in the semantic blocking task. The results revealed inhibitory reaction time effects of semantic context for both words and pictures, and a corresponding electrophysiological effect that could not be interpreted in terms of output processes. These data suggest that the electrophysiological effect of semantic context in the semantic blocking task does not reflect output processes, and therefore undermine an interpretation of this effect in terms of word selection.

  6. The Electrophysiology of Basic Phrase Building

    PubMed Central

    Lapinskaya, Natalia; Heffner, Christopher C.; Malko, Anton; Lau, Ellen F.

    2016-01-01

    A defining trait of linguistic competence is the ability to combine elements into increasingly complex structures to denote, and to comprehend, a potentially infinite number of meanings. Recent magnetoencephalography (MEG) work has investigated these processes by comparing the response to nouns in combinatorial (blue car) and non-combinatorial (rnsh car) contexts. In the current study we extended this paradigm using electroencephalography (EEG) to dissociate the role of semantic content from phonological well-formedness (yerl car). We used event-related potential (ERP) recordings in order to better relate the observed neurophysiological correlates of basic combinatorial operations to prior ERP work on comprehension. We found that nouns in combinatorial contexts (blue car) elicited a greater centro-parietal negativity between 180-400ms, independent of the phonological well-formedness of the context word. We discuss the potential relationship between this ‘combinatorial’ effect and classic N400 effects. We also report preliminary evidence for an early anterior negative deflection immediately preceding the critical noun in combinatorial contexts, which we tentatively interpret as an electrophysiological reflex of syntactic structure initialization. PMID:27711111

  7. Grafted dopamine neurons: Morphology, neurochemistry, and electrophysiology.

    PubMed

    Strömberg, Ingrid; Bickford, Paula; Gerhardt, Greg A

    2010-02-09

    Grafting of dopamine-rich tissue to counteract the symptoms in Parkinson's disease became a promising tool for future treatment. This article discusses how to improve the functional outcome with respect to graft outgrowth and functions of dopamine release and electrophysiological responses to graft implantation in the host brain striatal target. It has been documented that a subpopulation of the dopamine neurons innervates the host brain in a target-specific manner, while some of the grafted dopamine neurons never project to the host striatum. Neurochemical studies have demonstrated that the graft-induced outgrowth synthesize, store, metabolize and release dopamine and possibly other neurotransmitters such as 5-HT. Furthermore, the released dopamine affects the dopamine-depleted brain in areas that are larger than the graft-derived nerve fibers reach. While stem cells will most likely be the future source of cells to be used in grafting, it is important to find the guiding cues for how to reinnervate the dopamine-depleted striatum in a proper way with respect to the dopamine subpopulations of A9 and A10 to efficiently treat the motor abnormalities seen in Parkinson's disease.

  8. [On the first studies of electrophysiology].

    PubMed

    de Micheli, Alfredo

    2011-01-01

    A historical outline of the evolution of electrophysiology from the eighteenth century is shortly presented. Topics concerning the so called animal electricity starting from the observations on descharges of Torpedo fish until Bolognese Galvani's researches on the frogs are exposed. The points of view of their oppositionists also are examined. These ones, leaded by the physicist Alessandro Volta, professor in the University of Pavia, believed that electricity detected by galvanists was not inherent to animal but was due to the action of the metallic conductors present in the circuit: contact electricity. Only towards the middle of the nineteenth century the physicist Carlo Matteucci attained to demonstrate the existente of the real animal electricity in form of injury current. It was possible to determine that quantitatively thanks to the capillary electrometer built in 1872 by the French physicist Gabriel Lippmann. This instrument was used by the English physiologist Waller in order to obtain the primitive electrocardiographic tracings in humans (1887). At beginnings of the twentieth century, the Dutch professor Willem Einthoven, of the University of Leiden, introduced his string galvanometer which permitted to allow the modern electrocardiography. So it was possible to record the electrical potentials of myocardial cells, first in vitro, later in isolated and perfused heart, son after in dog's heart in situ and finally in human heart. Therefore now it is possible to effectuate endocardial and epicardial mappings, indispensable in order to diagnose and treat the cardiac arrhythmias.

  9. Electrophysiological study of Drosophila rhodopsin mutants

    PubMed Central

    1986-01-01

    Electrophysiological investigations were carried out on several independently isolated mutants of the ninaE gene, which encodes opsin in R1-6 photoreceptors, and a mutant of the ninaD gene, which is probably important in the formation of the rhodopsin chromophore. In these mutants, the rhodopsin content in R1-6 photoreceptors is reduced by 10(2)-10(6)-fold. Light-induced bumps recorded from even the most severely affected mutants are physiologically normal. Moreover, a detailed noise analysis shows that photoreceptor responses of both a ninaE mutant and a ninaD mutant follow the adapting bump model. Since any extensive rhodopsin-rhodopsin interactions are not likely in these mutants, the above results suggest that such interactions are not needed for the generation and adaptation of light-induced bumps. Mutant bumps are strikingly larger in amplitude than wild-type bumps. This difference is observed both in ninaD and ninaE mutants, which suggests that it is due to severe depletion of rhodopsin content, rather than to any specific alterations in the opsin protein. Lowering or buffering the intracellular calcium concentration by EGTA injection mimics the effects of the mutations on the bump amplitude, but, unlike the mutations, it also affects the latency and kinetics of light responses. PMID:3097245

  10. Electrophysiology of pumpkin seeds: Memristors in vivo

    PubMed Central

    Volkov, Alexander G.; Nyasani, Eunice K.; Tuckett, Clayton; Greeman, Esther A.; Markin, Vladislav S.

    2016-01-01

    ABSTRACT Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K+ channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds. PMID:26926652

  11. Organic transistors for electrophysiology (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Rivnay, Jonathan

    2015-10-01

    Efficient local transduction of biological signals is of critical importance for mapping brain activity and diagnosing pathological conditions. Traditional devices used to record electrophysiological signals are passive electrodes that require (pre)amplification with downstream electronics. Organic electrochemical transistors (OECTs) that utilize conducting polymer films as the channel have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance (>3 mS). The materials properties and physics of such transistors, however, remains largely unexplored thus limiting their potential. Here we show that the uptake of ionic charge from an electrolyte into a poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) OECT channel leads to a dependence of the effective capacitance on the entire volume of the film. Subsequently, device transconductance and time response vary with channel thickness, a defining characteristic that differentiates OECTs from field effect transistors, and provides a new degree of freedom for device engineering. Using this understanding we tailor OECTs for a variety of low (1-100 Hz) and high (1-10 kHz) frequency applications, including human electroencephalography, where high transconductance devices impart richer signal content without the need for additional amplification circuitry. We also show that the materials figure of merit OECTs is the product of hole mobility and volumetric capacitance of the channel, leading to design rules for novel high performance materials.

  12. Microsystems for cell-based electrophysiology

    NASA Astrophysics Data System (ADS)

    Yobas, Levent

    2013-08-01

    Among the electrophysiology techniques, the voltage clamp and its subsequent scaling to smaller mammalian cells, the so-called patch clamp, led to fundamental discoveries in the last century, revealing the ionic mechanisms and the role of single-ion channels in the generation and propagation of action potentials through excitable membranes (e.g. nerves and muscles). Since then, these techniques have gained a reputation as the gold standard of studying cellular ion channels owing to their high accuracy and rich information content via direct measurements under a controlled membrane potential. However, their delicate and skill-laden procedure has put a serious constrain on the throughput and their immediate utilization in the discovery of new cures targeting ion channels until researchers discovered ‘lab-on-a-chip’ as a viable platform for the automation of these techniques into a reliable high-throughput screening functional assay on ion channels. This review examines the innovative ‘lab-on-a-chip’ microtechnologies demonstrated towards this target over a period of slightly more than a decade. The technologies are categorically reviewed according to their considerations for design, fabrication, as well as microfluidic integration from a performance perspective with reference to their ability to secure G Ω seals (gigaseals) on cells, the norm broadly accepted among electrophysiologists for quality recordings that reflect ion-channel activity with high fidelity.

  13. Electrophysiology of pumpkin seeds: Memristors in vivo.

    PubMed

    Volkov, Alexander G; Nyasani, Eunice K; Tuckett, Clayton; Greeman, Esther A; Markin, Vladislav S

    2016-01-01

    Leon Chua, the discoverer of a memristor, theoretically predicted that voltage gated ion channels can be memristors. We recently found memristors in different plants such as the Venus flytrap, Mimosa pudica, Aloe vera, apple fruits, and in potato tubers. There are no publications in literature about the existence of memristors in seeds. The goal of this work was to discover if pumpkin seeds might have memristors. We selected Cucurbita pepo L., cv. Cinderella, Cucurbita maxima L. cv Warty Goblin, and Cucurbita maxima L., cv. Jarrahdale seeds for this analysis. In these seeds, we found the presence of resistors with memory. The analysis was based on cyclic voltammetry where a memristor should manifest itself as a nonlinear two-terminal electrical element, which exhibits a pinched hysteresis loop on a current-voltage plane for any bipolar cyclic voltage input signal. Dry dormant pumpkin seeds have very high electrical resistance without memristive properties. The electrostimulation by bipolar sinusoidal or triangular periodic waves induces electrical responses in imbibed pumpkin seeds with fingerprints of memristors. Tetraethylammonium chloride, an inhibitor of voltage gated K(+) channels, transforms a memristor to a resistor in pumpkin seeds. NPPB (5-Nitro-2-(3-phenylpropylamino)benzoic acid) inhibits the memristive properties of imbibed pumpkin seeds. The discovery of memristors in pumpkin seeds creates a new direction in the understanding of electrophysiological phenomena in seeds.

  14. Introduction to solid supported membrane based electrophysiology.

    PubMed

    Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

    2013-05-11

    The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

  15. Electrophysiological effects of ATP on brain neurones.

    PubMed

    Illes, P; Nieber, K; Nörenberg, W

    1996-12-01

    1. The electrophysiological effects of ATP on brain neurones are either due to the direct activation of P2 purinoceptors by the unmetabolized nucleotide or to the indirect activation of P1. purinoceptors by the degradation product adenosine. 2. Two subtypes of P2 purinoceptors are involved, a ligand-activated ion channel (P2X) and a G protein-coupled receptor (P2Y). Hence, the stimulation of P2X purinoceptors leads to a cationic conductance increase, while the stimulation of P2Y purinoceptors leads to a G protein-mediated opening or closure of potassium channels. 3. ATP may induce a calcium-dependent potassium current by increasing the intracellular Ca2+ concentration. This is due either to the entry of Ca2+ via P2X purinoceptors or to the activation of metabotropic P2Y purinoceptors followed by signaling via the G protein/phospholipase C/inositol 1,4,5-trisphosphate (IP3) cascade. Eventually, IP3 releases Ca2+ from its intracellular pools. 4. There is no convincing evidence for the presence of P2U purinoceptors sensitive to both ATP and UTP, or pyrimidinoceptors sensitive to UTP only, in the central nervous system (CNS). 5. ATP-sensitive P2X and P2Y purinoceptors show a wide distribution in the CNS and appear to regulate important neuronal functions.

  16. Essentials of photometry for clinical electrophysiology of vision.

    PubMed

    McCulloch, Daphne L; Hamilton, Ruth

    2010-08-01

    Electrophysiological testing of the visual system requires familiarity with photometry. This technical note outlines the concepts of photometry with a focus on information relevant to clinical ERG and VEP testing. Topics include photometric quantities, consideration of pupil size, specification of brief extended flash stimuli, and the influence of the spectral composition of visual stimuli. Standard units and terms are explained in the context of the ISCEV standards and guidelines for clinical electrophysiology of vision.

  17. Ion channels at the nucleus: electrophysiology meets the genome.

    PubMed

    Matzke, Antonius J M; Weiger, Thomas M; Matzke, Marjori

    2010-07-01

    The nuclear envelope is increasingly viewed from an electrophysiological perspective by researchers interested in signal transduction pathways that influence gene transcription and other processes in the nucleus. Here, we describe evidence for ion channels and transporters in the nuclear membranes and for possible ion gating by the nuclear pores. We argue that a systems-level understanding of cellular regulation is likely to require the assimilation of nuclear electrophysiology into molecular and biochemical signaling pathways.

  18. Chronic homocysteine exposure causes changes in the intrinsic electrophysiological properties of cultured hippocampal neurons.

    PubMed

    Schaub, Christina; Uebachs, Mischa; Beck, Heinz; Linnebank, Michael

    2013-04-01

    Homocystinuria is an inborn error of metabolism characterized by plasma homocysteine levels up to 500 μM, premature vascular events and mental retardation. Mild elevations of homocysteine plasma levels up to 25 μM, which are common in the general population, are associated with vascular disease, cognitive impairment and neurodegeneration. Several mechanisms of homocysteine neurotoxicity have been investigated. However, information on putative effects of hyperhomocysteinemia on the electrophysiology of neurons is limited. To screen for such effects, we examined primary cultures of mouse hippocampal neurons with the whole-cell patch-clamp technique. Homocysteine was applied intracellularly (100 μM), or cell cultures were incubated with 100 μM homocysteine for 24 h. Membrane voltage was measured in current-clamp mode, and action potential firing was induced with short and prolonged current injections. Single action potentials induced by short current injections (5 ms) were not altered by acute application or incubation of homocysteine. When we elicited trains of action potentials with prolonged current injections (200 ms), a broadening of action potentials during repetitive firing was observed in control neurons. This spike broadening was unaltered by acute application of homocysteine. However, it was significantly diminished when incubation with homocysteine was extended to 24 h prior to recording. Furthermore, the number of action potentials elicited by low current injections was reduced after long-term incubation with homocysteine, but not by the acute application. After 24 h of homocysteine incubation, the input resistance was reduced which might have contributed to the observed alterations in membrane excitability. We conclude that homocysteine exposure causes changes in the intrinsic electrophysiological properties of cultured hippocampal neurons as a mechanism of neurological symptoms of hyperhomocysteinemia.

  19. Core binding factor acute myeloid leukemia (CBF-AML) in México: a single institution experience.

    PubMed

    Ruiz-Delgado, Guillermo J; Macías-Gallardo, Julio; Lutz-Presno, Julia; Garcés-Eisele, Javier; Hernández-Arizpe, Ana; Montes-Montiel, Maryel; Ruiz-Argüelles, Guillermo J

    2011-01-01

    Twenty one patients with CBF-AML presented prospectively in the Centro de Hematología y Medicina Interna de Puebla (Puebla, México) between February 1995 and March 2010, 14 with the t(8;21)(q22;q22) and 7 with the inv(16)(p13;q22)/t(16;16)(p13;q22); they represent 13% of all cases of AML. The median age of the patients was 24 years (range 1 to 61). Seven of 14 patients with t(8;21)(q22;q22) had an M2 morphology whereas 3/7 with the inv(16) had an M4 morphology; in addition to the myeloid markers identified by flow-cytometry (surface CD13, surface CD33, and cytoplasmic myeloperoxidase) lymphoid markers were identified in the blast cells of 8/14 cases of the t(8;21) patients, but in no patient with the inv(16). Nineteen patients were treated with combined chemotherapy and 16 (84%) achieved a complete molecular remission. Seven patients were auto or allografted. Relapses presented in 10/16 patients. The median probability of overall survival (OS) has not been reached being above 165 months, whereas the 165-month probability of OS and leukemia-free survival was 52%; despite a tendency for a better outcome of patients with the t(8;21), there were no significant differences in survival of patients with either the t(8;21) or the inv(16). In this single institution experience in México, we found that the CBF variants of AML have a similar prevalence as compared with Caucasian populations, that the co-expression of lymphoid markers in the blast cells was frequent in the t(8;21) and that these two AML subtypes were associated with a relatively good long-term prognosis. Further studies are needed to describe with more detail the precise biological features of these molecular subtypes of acute leukemia.

  20. Patients admitted with an acute exacerbation of chronic obstructive pulmonary disease had positive experiences exercising from the beginning of their hospital stay: a qualitative analysis.

    PubMed

    Tang, Clarice Y; Taylor, Nicholas F; Blackstock, Felicity C

    2013-01-01

    The aim of the study is to explore the experiences of inpatients with an acute exacerbation of chronic obstructive pulmonary disease, who participated in a very early exercise programme while acutely unwell. This qualitative study analysed responses from participant interviews as part of a mixed method trial whereby participants were randomly allocated into three groups: low intensity, moderate to high intensity aerobic and resistance exercises or a control group who received routine physiotherapy. Everyone allocated to the exercise groups were invited to participate in the qualitative study. Interviews were within a week post discharge and the results were analysed thematically. A total of 19 participants were interviewed and described their experience as positive and beneficial and reported an increased motivation towards exercising. These findings converged with the high levels of exercise adherence (83%) and within-group improvements in walking capacity observed in both exercise groups. Participants also reported commencement of a home exercise programme after discharge but intention to participate in community pulmonary rehabilitation remained low. Participation in a very early exercise programme while acutely unwell can lead to positive attitude towards exercise. The results converge with the quantitative results that provided preliminary evidence of programme feasibility and within-group improvement in exercise tolerance.

  1. Bayesian Quantitative Electrophysiology and Its Multiple Applications in Bioengineering

    PubMed Central

    Barr, Roger C.; Nolte, Loren W.; Pollard, Andrew E.

    2014-01-01

    Bayesian interpretation of observations began in the early 1700s, and scientific electrophysiology began in the late 1700s. For two centuries these two fields developed mostly separately. In part that was because quantitative Bayesian interpretation, in principle a powerful method of relating measurements to their underlying sources, often required too many steps to be feasible with hand calculation in real applications. As computer power became widespread in the later 1900s, Bayesian models and interpretation moved rapidly but unevenly from the domain of mathematical statistics into applications. Use of Bayesian models now is growing rapidly in electrophysiology. Bayesian models are well suited to the electrophysiological environment, allowing a direct and natural way to express what is known (and unknown) and to evaluate which one of many alternatives is most likely the source of the observations, and the closely related receiver operating characteristic (ROC) curve is a powerful tool in making decisions. Yet, in general, many people would ask what such models are for, in electrophysiology, and what particular advantages such models provide. So to examine this question in particular, this review identifies a number of electrophysiological papers in bio-engineering arising from questions in several organ systems to see where Bayesian electrophysiological models or ROC curves were important to the results that were achieved. PMID:22275206

  2. Electrophysiological Determination of Submembrane Na(+) Concentration in Cardiac Myocytes.

    PubMed

    Hegyi, Bence; Bányász, Tamás; Shannon, Thomas R; Chen-Izu, Ye; Izu, Leighton T

    2016-09-20

    In the heart, Na(+) is a key modulator of the action potential, Ca(2+) homeostasis, energetics, and contractility. Because Na(+) currents and cotransport fluxes depend on the Na(+) concentration in the submembrane region, it is necessary to accurately estimate the submembrane Na(+) concentration ([Na(+)]sm). Current methods using Na(+)-sensitive fluorescent indicators or Na(+) -sensitive electrodes cannot measure [Na(+)]sm. However, electrophysiology methods are ideal for measuring [Na(+)]sm. In this article, we develop patch-clamp protocols and experimental conditions to determine the upper bound of [Na(+)]sm at the peak of action potential and its lower bound at the resting state. During the cardiac cycle, the value of [Na(+)]sm is constrained within these bounds. We conducted experiments in rabbit ventricular myocytes at body temperature and found that 1) at a low pacing frequency of 0.5 Hz, the upper and lower bounds converge at 9 mM, constraining the [Na(+)]sm value to ∼9 mM; 2) at 2 Hz pacing frequency, [Na(+)]sm is bounded between 9 mM at resting state and 11.5 mM; and 3) the cells can maintain [Na(+)]sm to the above values, despite changes in the pipette Na(+) concentration, showing autoregulation of Na(+) in beating cardiomyocytes.

  3. A Multicenter Experience from Lebanon in Childhood and Adolescent Acute Myeloid Leukemia: High rate of Early Death in Childhood Acute Promyelocytic Leukemia

    PubMed Central

    Farah, Roula A.; Horkos, Jessy G.; Bustros, Youssef D.; Farhat, Hussein Z.; Abla, Oussama

    2015-01-01

    Background Acute myeloid leukemia (AML) is a disease with marked heterogeneity. Despite major improvement in outcome, it remains a life-threatening malignancy. Demographic and clinical data on pediatric AML is lacking among the Lebanese population. Purpose We aimed to identify clinical, molecular and outcome data in children with AML in Lebanon. Methods A retrospective chart review of children with AML diagnosed in three Lebanese hospitals during the past 8 years was conducted. Results From May 2002 through March 2010, we identified 24 children with AML in Saint George Hospital University Medical Center, University Medical Center Rizk Hospital, and Abou-Jaoude Hospital. Males and females were equally represented; median age at diagnosis was 9 years (range 1–24) and median WBC at diagnosis was 31 × 109/L (range: 2.1–376 × 109/L). Twenty five percent of patients (6 out of 24) had acute promyelocytic leukemia (APL). Karyotype was normal in 33% of patients; t(8;21), inv (16), t(8;9), t(7;11), t(9;11), complex chromosomal abnormality, monosomy 7 and trisomy 8 were the most common cytogenetic abnormalities encountered. Patients were treated on different European and North American protocols. Twelve patients (50%) achieved morphologic CR after cycle 1, 6 of them (50%) had bone marrow relapse within 11 months from diagnosis. Nine patients underwent allogeneic stem cell transplant, and 3 of them are alive at 5 years post-transplant. Early death rate was 16.6% of patients, mainly those with APL and a presenting WBC > 10 × 109/L. Fifty per cent of APL patients had an early death due to DIC despite starting ATRA therapy. Overall, median survival for AML patients who died from disease progression was 25.8 months (range: 1–60 months). Overall disease-free survival was 30.4%. Patients < 10 years of age had a 50% survival rate compared to 0% in patients > 10 years. Conclusions Our report highlights the needs in Lebanon for better supportive care of children with APL

  4. Hemodialysis among pregnancy related acute kidney injury patients: A single center experience in North-Western Nigeria.

    PubMed

    Makusidi, A M; Liman, H M; Yakubu, A; Hassan, M; Isah, M D; Chijioke, A

    2016-09-01

    Pregnancy related acute kidney injury (PRAKI) patients that underwent hemodialysis (HD) between May 2007 and April 2015 were studied with specific reference to clinical features, laboratory values, duration of pregnancy at the diagnosis of acute kidney injury and outcome. It involved 38 patients aged between 15 and 30 years. The main clinical features were fever, edema and oliguria. The leading etiological factors included ante/postpartum hemorrhage, septic abortion, and toxemia of pregnancy. The majority of cases occurred during the third trimester. PRAKI is a dreaded complication of pregnancy with high morbidity and mortality. HD improved patient survival in our study.

  5. Effects of heavy ions on visual function and electrophysiology of rodents: the ALTEA-MICE project

    NASA Technical Reports Server (NTRS)

    Sannita, W. G.; Acquaviva, M.; Ball, S. L.; Belli, F.; Bisti, S.; Bidoli, V.; Carozzo, S.; Casolino, M.; Cucinotta, F.; De Pascale, M. P.; Di Fino, L.; Di Marco, S.; Maccarone, R.; Martello, C.; Miller, J.; Narici, L.; Peachey, N. S.; Picozza, P.; Rinaldi, A.; Ruggieri, D.; Saturno, M.; Schardt, D.; Vazquez, M.; Lowenstein, D. (Principal Investigator)

    2004-01-01

    ALTEA-MICE will supplement the ALTEA project on astronauts and provide information on the functional visual impairment possibly induced by heavy ions during prolonged operations in microgravity. Goals of ALTEA-MICE are: (1) to investigate the effects of heavy ions on the visual system of normal and mutant mice with retinal defects; (2) to define reliable experimental conditions for space research; and (3) to develop animal models to study the physiological consequences of space travels on humans. Remotely controlled mouse setup, applied electrophysiological recording methods, remote particle monitoring, and experimental procedures were developed and tested. The project has proved feasible under laboratory-controlled conditions comparable in important aspects to those of astronauts' exposure to particle in space. Experiments are performed at the Brookhaven National Laboratories [BNL] (Upton, NY, USA) and the Gesellschaft fur Schwerionenforschung mbH [GSI]/Biophysik (Darmstadt, FRG) to identify possible electrophysiological changes and/or activation of protective mechanisms in response to pulsed radiation. Offline data analyses are in progress and observations are still anecdotal. Electrophysiological changes after pulsed radiation are within the limits of spontaneous variability under anesthesia, with only indirect evidence of possible retinal/cortical responses. Immunostaining showed changes (e.g. increased expression of FGF2 protein in the outer nuclear layer) suggesting a retinal stress reaction to high-energy particles of potential relevance in space. c2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  6. Initial outcome following invasive cardiac electrophysiologic studies and radiofrequency ablation of atrial fibrillation

    PubMed Central

    Uwanuruochi, Kelechukwu; Saravanan, Sabari; Ganasekar, Anita; Solomon, Benjamin S; Murugesan, Ravikumar; Shah, Ruchit A; Krishnamoorthy, Jaishankar; Pandurangi, Ulhas M

    2016-01-01

    Background: Cardiac electrophysiologic study and radiofrequency ablation (RFA) have become an established mode of treatment for patients with refractory arrhythmias. These procedures are carried out regularly at the cardiac catheterization laboratory of Madras Medical Mission India. Objective: The purpose of this study was to evaluate our experience with cardiac electrophysiologic studies (EPS) and RFA catheter of atrial fibrillation (AF). Materials and Methods: This was a retrospective study carried out in the Cardiac Electrophysiology Department of the Institute of Cardiovascular Diseases, Madras Medical Mission, India. All cases diagnosed to have AF following cardiac EPS between January 2010 and April 2014 was selected for the study. The records, which were obtained from the Cardiac Electrophysiology Clinical Research Office of Madras Medical Mission, were reviewed. Forty-nine cases were chosen for analysis, using SPSS statistical software version 15. Results: There were 49 patients, 23 males and 26 females. The mean age was 57.53 years. Commonly associated diseases were diabetes mellitus 8 (16.3%), hypertension 18 (36.7%), and coronary heart disease 14 (28.5%). The ventricular rate was rapid most cases (91.2%). AF was diagnosed as being paroxysmal in 40 (81.6%), persistent in 5 (10.2%), chronic in 3 (6.1%), and lone in 1 (2.0%). Ablation was carried out in 28 (57.1%), the success rate being 90% for pulmonary vein isolation, and 90.9% for atrioventricular node ablation. Complication rate was 2.04%. Conclusions: Treatment of AF by RFA is highly effective and safe. PMID:27127736

  7. [Surgical treatment in severe acute pancreatitis. Last 15 years of experience in Emergency County Hospital of Baia Mare].

    PubMed

    Leşe, Mihaela; Tămăşan, Anca; Stoicescu, B; Brânduşe, M; Puia, Ioana; Mare, C; Lazăr, C

    2005-01-01

    The aim of this study is to investigate the particular course of the patients operated for severe acute pancreatitis in a period of 15 years in surgical department of Emergency County Hospital of Baia Mare. Medical records of 202 patients admitted and operated for severe acute pancreatitis, were studied. Follow-up parameters were: age, gender, etiology, moment of operation, the type of operations and postoperative evolution of this patients. In the group of deceased patients alcoholic etiology of pancreatitis was prevailing. Almost a half of patients were operated in the first day of admission. A high number of patients were operated for diagnosis of acute abdomen with intention of exploratory laparotomy. In the last years, besides the usual closed drainage, open drainage and planning drainage were performed. Postoperative mortality is still high. The diagnose of severe acute pancreatitis is difficult in emergency. Global mortality in pancreatitis remains high, especially in the period of enzymatic shock, and is correlated with masculine gender, alcoholic etiology and somewhat with precocity of operation.

  8. Experiences of the Implementation of a Learning Disability Nursing Liaison Service within an Acute Hospital Setting: A Service Evaluation

    ERIC Educational Resources Information Center

    Castles, Amy; Bailey, Carol; Gates, Bob; Sooben, Roja

    2014-01-01

    It has been well documented that people with learning disabilities receive poor care in acute settings. Over the last few years, a number of learning disability liaison nurse services have developed in the United Kingdom as a response to this, but there has been a failure to systematically gather evidence as to their effectiveness. This article…

  9. Traumatic Brain Injury Detection Using Electrophysiological Methods

    PubMed Central

    Rapp, Paul E.; Keyser, David O.; Albano, Alfonso; Hernandez, Rene; Gibson, Douglas B.; Zambon, Robert A.; Hairston, W. David; Hughes, John D.; Krystal, Andrew; Nichols, Andrew S.

    2015-01-01

    Measuring neuronal activity with electrophysiological methods may be useful in detecting neurological dysfunctions, such as mild traumatic brain injury (mTBI). This approach may be particularly valuable for rapid detection in at-risk populations including military service members and athletes. Electrophysiological methods, such as quantitative electroencephalography (qEEG) and recording event-related potentials (ERPs) may be promising; however, the field is nascent and significant controversy exists on the efficacy and accuracy of the approaches as diagnostic tools. For example, the specific measures derived from an electroencephalogram (EEG) that are most suitable as markers of dysfunction have not been clearly established. A study was conducted to summarize and evaluate the statistical rigor of evidence on the overall utility of qEEG as an mTBI detection tool. The analysis evaluated qEEG measures/parameters that may be most suitable as fieldable diagnostic tools, identified other types of EEG measures and analysis methods of promise, recommended specific measures and analysis methods for further development as mTBI detection tools, identified research gaps in the field, and recommended future research and development thrust areas. The qEEG study group formed the following conclusions: (1) Individual qEEG measures provide limited diagnostic utility for mTBI. However, many measures can be important features of qEEG discriminant functions, which do show significant promise as mTBI detection tools. (2) ERPs offer utility in mTBI detection. In fact, evidence indicates that ERPs can identify abnormalities in cases where EEGs alone are non-disclosing. (3) The standard mathematical procedures used in the characterization of mTBI EEGs should be expanded to incorporate newer methods of analysis including non-linear dynamical analysis, complexity measures, analysis of causal interactions, graph theory, and information dynamics. (4) Reports of high specificity in q

  10. [Electrophysiological testing in spinal cord tumors].

    PubMed

    André-Obadia, N; Mauguière, F

    2017-02-01

    Evoked potentials (EPs) are useful to evaluate the functional impairment of motor and somatosensory pathways in spinal cord tumors. Conduction through pyramidal tracts is evaluated by motor EPs (MEPs) elicited by transcranial stimulation, magnetic for awake patients or electric in the operating room. Somatosensory EPs (SEPs) and laser EPs (LEPs) are complementary procedures to explore conduction in dorsal columns and spinothalamic tracts, respectively. MEPs as well as SEPs show conduction abnormalities in about 60% of cases with a sensitivity that increases up to 70% when both procedures are carried out. Abnormalities are observed in the absence of any clinical sign in respectively 7% and 15% of cases for MEPs and SEPs. Multilevel stimulations for SEPs recordings permit to detect segmental dysfunction in 70% in case of cervical TIM, even in the absence of clinical signs. LEPs are useful in specific clinical situations: they allow a dermatomal stimulation and are correlated to segmental thermoalgic anaesthesia. Electrophysiological testing plays an important role in the diagnostic and therapeutic strategy: before surgery, MEPs and SEPs objectively evaluate the functional impairment directly related to the lesion. They also help by permitting a follow-up, either before surgery when the surgical decision is delayed because of a good clinical tolerance of the lesion, or after operation to evaluate the functional evolution. Intraoperative monitoring of MEPs and SEPs allows informing the surgeon about the impact on each surgical manipulation. No prospective randomized study has been performed to date to compare clinical evolution after surgery with or without monitoring. Nevertheless, a wide consensus became established in favor of monitoring to limit the risk of postoperative definite deficit and to permit an optimal surgical resection without risk when responses are preserved.

  11. Comparison of Electrophysiological Auditory Measures in Fishes.

    PubMed

    Maruska, Karen P; Sisneros, Joseph A

    2016-01-01

    Sounds provide fishes with important information used to mediate behaviors such as predator avoidance, prey detection, and social communication. How we measure auditory capabilities in fishes, therefore, has crucial implications for interpreting how individual species use acoustic information in their natural habitat. Recent analyses have highlighted differences between behavioral and electrophysiologically determined hearing thresholds, but less is known about how physiological measures at different auditory processing levels compare within a single species. Here we provide one of the first comparisons of auditory threshold curves determined by different recording methods in a single fish species, the soniferous Hawaiian sergeant fish Abudefduf abdominalis, and review past studies on representative fish species with tuning curves determined by different methods. The Hawaiian sergeant is a colonial benthic-spawning damselfish (Pomacentridae) that produces low-frequency, low-intensity sounds associated with reproductive and agonistic behaviors. We compared saccular potentials, auditory evoked potentials (AEP), and single neuron recordings from acoustic nuclei of the hindbrain and midbrain torus semicircularis. We found that hearing thresholds were lowest at low frequencies (~75-300 Hz) for all methods, which matches the spectral components of sounds produced by this species. However, thresholds at best frequency determined via single cell recordings were ~15-25 dB lower than those measured by AEP and saccular potential techniques. While none of these physiological techniques gives us a true measure of the auditory "perceptual" abilities of a naturally behaving fish, this study highlights that different methodologies can reveal similar detectable range of frequencies for a given species, but absolute hearing sensitivity may vary considerably.

  12. A Comparison between Mechanical Thrombectomy and Intra-arterial Fibrinolysis in Acute Basilar Artery Occlusion: Single Center Experiences

    PubMed Central

    Jung, Seunguk; Jung, Cheolkyu; Bae, Yun Jung; Choi, Byung Se; Kim, Jae Hyoung; Lee, Sang-Hwa; Chang, Jun Young; Kim, Beom Joon; Han, Moon-Ku; Bae, Hee-Joon; Kwon, Bae Ju; Cha, Sang-Hoon

    2016-01-01

    Background and Purpose Recent advances in intra-arterial techniques and thrombectomy devices lead to high rate of recanalization. However, little is known regarding the effect of the evolvement of endovascular revascularization therapy (ERT) in acute basilar artery occlusion (BAO). We compared the outcome of endovascular mechanical thrombectomy (EMT) versus intra-arterial fibrinolysis (IAF)-based ERT in patients with acute BAO. Methods After retrospectively reviewed a registry of consecutive patients with acute ischemic stroke who underwent ERT from September 2003 to February 2015, 57 patients with acute BAO within 12 hours from stroke onset were enrolled. They were categorized as an IAF group (n=24) and EMT group (n=33) according to the primary technical option. We compared the procedural and clinical outcomes between the groups. Results The time from groin puncture to recanalization was significantly shorter in the EMT group than in the IAF group (48.5 [25.3 to 87.8] vs. 92 [44 to 179] minutes; P=0.02) The rate of complete recanalization was significantly higher in the EMT group than in the IAF group (87.9% vs 41.7%; P<0.01). The good outcome of the modified Rankin Scale score≤2 at 3 months was more frequent in the EMT group than in the IAF group, but it was not statistically significant (39.4% vs 16.7%; P=0.06). Conclusions EMT-based ERT in patients with acute BAO is superior to IAF-based ERT in terms of the reduction of time from groin puncture to recanalization and the improvement of the rate of complete recanalization. PMID:27283281

  13. Is Satisfaction with the Acute-Care Experience Higher amongst Consumers Treated in the Private Sector? A Survey of Public and Private Sector Arthroplasty Recipients

    PubMed Central

    Naylor, Justine M.; Descallar, Joseph; Grootemaat, Mechteld; Badge, Helen; Harris, Ian A.; Simpson, Grahame; Jenkin, Deanne

    2016-01-01

    Background Consumer satisfaction with the acute-care experience could reasonably be expected to be higher amongst those treated in the private sector compared to those treated in the public sector given the former relies on high-level satisfaction of its consumers and their subsequent recommendations to thrive. The primary aims of this study were to determine, in a knee or hip arthroplasty cohort, if surgery in the private sector predicts greater overall satisfaction with the acute-care experience and greater likelihood to recommend the same hospital. A secondary aim was to determine whether satisfaction across a range of service domains is also higher in the private sector. Methods A telephone survey was conducted 35 days post-surgery. The hospital cohort comprised eight public and seven private high-volume arthroplasty providers. Consumers rated overall satisfaction with care out of 100 and likeliness to recommend their hospital on a 5-point Likert scale. Additional Likert-style questions were asked covering specific service domains. Generalized estimating equation models were used to analyse overall satisfaction (dichotomised as ≥ 90 or < 90) and future recommendations for care (dichotomised as ‘definitely recommend’ or ‘other’), whilst controlling for covariates. The proportions of consumers in each sector reporting the best Likert response for each individual domain were compared using non-parametric tests. Results 457 survey respondents (n = 210 private) were included. Less patient-reported joint impairment pre-surgery [OR 1.03 (95% CI 1.01–1.05)] and absence of an acute complication (OR 2.13 95% CI 1.41–3.23) significantly predicted higher overall satisfaction. Hip arthroplasty [OR 1.84 (1.1–2.96)] and an absence of an acute complication [OR 2.31 (1.28–4.17] significantly predicted greater likelihood for recommending the hospital. The only care domains where the private out-performed the public sector were hospitality (46.7 vs 35.6%, p <0

  14. Electrophysiological response of chicken's jejunal epithelium to increasing levels of T-2 toxin.

    PubMed

    Yunus, Agha Waqar; Kröger, Susan; Tichy, Alexander; Zentek, Jürgen; Böhm, Josef

    2013-02-01

    The present investigations were conducted to test the effects of T-2 toxin on electrophysiological variables of jejunal epithelium of chicken. Jejunal segments of broilers were monitored in Ussing chambers in the presence of T-2 toxin at the levels of 0 (negative control), 0 (methanol/vehicle control), 0.1, 1, 5, and 10 μg/ml of buffer. T-2 toxin did not affect basal values of short circuit current (I(sc)), transmural potential difference, or tissue conductivity in the jejunal epithelium. T-2 toxin also did not statistically affect glucose-induced electrophysiological variables during the first 3 min of glucose induction. Compared to the vehicle control, the ouabain-sensitive I(sc) was negatively affected (P = 0.008) only under 5 μg of T-2 toxin/ml. Increasing levels of T-2 toxin negatively affected the ouabain-sensitive I(sc) in a cubic (P = 0.007) fashion. These data indicate that acute exposure to moderate levels of T-2 toxin may progressively impair the cation gradient across the jejunal epithelium.

  15. A novel total variation based noninvasive transmural electrophysiological imaging.

    PubMed

    Xu, Jingjia; Dehaghani, Azar Rahimi; Gao, Fei; Wang, Linwei

    2013-01-01

    While tomographic imaging of cardiac structure and kinetics has improved substantially, electrophysiological mapping of the heart is still restricted to the body or heart surface with little or no depth information beneath. The progress in reconstructing transmural action potentials from surface voltage data has been hindered by the challenges of intrinsic ill-posedness and the lack of a unique solution in the absence of prior assumptions. In this work, we propose to exploit the unique spatial property of transmural action potentials that it is often piece-wise smooth with a steep boundary (gradient) separating the depolarized and repolarized regions. This steep gradient could reveal normal or disrupted electrical propagation wavefronts, or pinpoint the border between viable and necrotic tissue. In this light, we propose a novel adaption of the total-variation (TV) prior into the reconstruction of transmural action potentials, where a variational TV operator is defined instead of a common discrete operator, and the TV-minimization is solved by a sequence of weighted, first-order L2-norm minimizations. In a large set of phantom experiments performed on image-derived human heart-torso models, the proposed method is shown to outperform existing quadratic methods in preserving the steep gradient of action potentials along the border of infarcts, as well as in capturing the disruption to the normal path of electrical wavefronts. The former is further attested by real-data experiments on two post-infarction human subjects, demonstrating the potential of the proposed method in revealing the location and shape of the underlying infarcts when existing quadratic methods fail to do so.

  16. Noninvasive computational imaging of cardiac electrophysiology for 3-D infarct.

    PubMed

    Wang, Linwei; Wong, Ken C L; Zhang, Heye; Liu, Huafeng; Shi, Pengcheng

    2011-04-01

    Myocardial infarction (MI) creates electrophysiologically altered substrates that are responsible for ventricular arrhythmias, such as tachycardia and fibrillation. The presence, size, location, and composition of infarct scar bear significant prognostic and therapeutic implications for individual subjects. We have developed a statistical physiological model-constrained framework that uses noninvasive body-surface-potential data and tomographic images to estimate subject-specific transmembrane-potential (TMP) dynamics inside the 3-D myocardium. In this paper, we adapt this framework for the purpose of noninvasive imaging, detection, and quantification of 3-D scar mass for postMI patients: the framework requires no prior knowledge of MI and converges to final subject-specific TMP estimates after several passes of estimation with intermediate feedback; based on the primary features of the estimated spatiotemporal TMP dynamics, we provide 3-D imaging of scar tissue and quantitative evaluation of scar location and extent. Phantom experiments were performed on a computational model of realistic heart-torso geometry, considering 87 transmural infarct scars of different sizes and locations inside the myocardium, and 12 compact infarct scars (extent between 10% and 30%) at different transmural depths. Real-data experiments were carried out on BSP and magnetic resonance imaging (MRI) data from four postMI patients, validated by gold standards and existing results. This framework shows unique advantage of noninvasive, quantitative, computational imaging of subject-specific TMP dynamics and infarct mass of the 3-D myocardium, with the potential to reflect details in the spatial structure and tissue composition/heterogeneity of 3-D infarct scar.

  17. Augmentation of serotonin enhances pleasant and suppresses unpleasant cortical electrophysiological responses to visual emotional stimuli in humans.

    PubMed

    Kemp, Andrew H; Gray, Marcus A; Silberstein, Richard B; Armstrong, Stuart M; Nathan, Pradeep J

    2004-07-01

    The serotonergic system is one of the major systems targeted in the pharmacological treatment of a wide range of mood disorders including depression; however, little is known about the neurophysiological mechanisms underlying the effects of serotonin (5-HT) on affective phenomena including emotional behaviours, mood and emotional processing. The aim of the current study was to investigate how 5-HT acutely modulates steady-state visually evoked potentials (SSVEP), heart rate (HR) and verbal ratings associated with the viewing of differently valent emotional images. In a randomised double-blind, placebo-controlled design, 17 healthy subjects were tested under two acute treatment conditions: placebo and citalopram (20 mg) (a selective serotonin re-uptake inhibitor, or SSRI). Participants were tested 2 h post treatment whilst viewing 75 images (categorised as pleasant, neutral or unpleasant). Results indicate that under placebo treatment, processing of unpleasant valence [unpleasant (-) neutral images] was associated with decreases in SSVEP amplitude and latency in frontal and occipital cortices, whereas processing of pleasant valence [pleasant (-) neutral images] was associated with amplitude decreases and latency increases within frontal and left temporoparietal cortices. Decreases in both amplitude and latency are both interpreted as surrogate measures of cortical activation or excitation. Citalopram relative to placebo attenuated the electrophysiological activation to unpleasant valence within frontal and occipital cortices, but potentiated electrophysiological activation (amplitude only) to pleasant valence within parietooccipital cortices. Citalopram relative to placebo also suppressed differences in heart rate associated with the viewing of pleasant and unpleasant images, but did not alter subject's subjective responses to emotional images. Results suggest that responsiveness to pleasant and unpleasant stimuli following neurochemical modulation may vary across

  18. A review of three years experience using email and videoconferencing for the delivery of post-acute burns care to children in Queensland.

    PubMed

    Smith, Anthony C; Youngberry, Karen; Mill, Julie; Kimble, Roy; Wootton, Richard

    2004-05-01

    A virtual outpatient service has been established in Queensland for the delivery of post-acute burns care to children living in rural and remote areas of the state. The integration of telepaediatrics as a routine service has reduced the need for patient travel to the specialist burns unit situated in Brisbane. We have conducted 293 patient consultations over a period of 3 years. A retrospective review of our experience has shown that post-acute burns care can be delivered using videoconferencing, email and the telephone. Telepaediatric burns services have been valuable in two key areas. The first area involves a programme of routine specialist clinics via videoconference. The second area relates to ad-hoc patient consultations for collaborative management during acute presentations and at times of urgent clinical need. The families of patients have expressed a high degree of satisfaction with the service. Telepaediatric services have helped improve access to specialist services for people living in rural and remote communities throughout Queensland.

  19. Experience with a Simplified Computer Based Intensive Care Monitoring System in the Management of Acutely Ill Surgical Patients

    PubMed Central

    Hadley, H. Roger; Rutherford, Harold G.; Smith, Louis L.; Briggs, Burton A.; Neilsen, Ivan R.; Rau, Richard

    1979-01-01

    The need exists for a simplified and ecomonical computer based monitoring system for critically ill surgical patients. Such a system would enjoy widespread use in surgical intensive care units in regional, as well as larger community hospitals. We have assembled such a system which provides digital readout of the usual physiologic parameters, and also provide computer storage of accumulated data for review and evaluation of patient care. The computer provides graphic and digital display and digital printout for subsequent inclusion in the patient records. Most frequent indications for this system include the development of acute respiratory insufficiency or acute circulatory failure due to invasive sepsis and/or severe arteriosclerotic cardiovascular disease. Information most beneficial in patient care included measurement of cardiac output;alveolar arterial oxygen gradient. ImagesFigure 1Figure 5Figure 9Figure 11

  20. Plasma-exchange as a "rescue therapy" for dermato/polymyositis in acute phase. Experience in three young patients.

    PubMed

    Cozzi, Franco; Marson, Piero; Pigatto, Erika; Tison, Tiziana; Polito, Pamela; Galozzi, Paola; De Silvestro, Giustina; Punzi, Leonardo

    2015-12-01

    There are few data in the literature supporting the efficacy of plasma-exchange in dermato/polymyositis. The authors report three cases of patients with acute disease phase showing severe pharyngo-esophageal muscle weakness unresponsive to conventional therapy (corticosteroids and immunosuppressant agents) who were treated with plasma-exchange. As the patients were at high risk of "aspiration pneumonia", tracheostomy and PEG tubes were placed. The patients underwent a series of plasma-exchange for a mean of 15 weeks, during which time they progressively recovered muscle strength, their serum muscle enzyme values returned to normal levels, and MRI showed resolution of muscle edema. The tracheostomy and PEG tubes could be removed. Our findings suggest that plasma-exchange in association with immunosuppressant agents could play a relevant role in the management of dermato/polymyositis in acute phase.

  1. Method of bioindication for evaluation of the effects of plant extracts on cell monolayer in acute and chronic experiments.

    PubMed

    Seregina, M V; Mikhailova, L P

    2002-04-01

    Acute and chronic toxicities of plant extracts for external use were studied on a model of cell monolayer. This method detects the toxic dose of the agent during the first stage of the study; the activity of this dose and severity of damaging effect can be further studied on experimental animals. An advantage of the method is high informative value of preliminary investigation in the development of new low-toxic agents.

  2. Electrophysiology of globus pallidus neurons in vitro.

    PubMed

    Nambu, A; Llinaś, R

    1994-09-01

    1. We investigated the electrical properties of globus pallidus neurons intracellularly using brain slices from adult guinea pigs. Three types of neurons were identified according to their intrinsic electrophysiological properties. 2. Type I neurons (59%) were silent at the resting membrane level (-65 +/- 10 mV, mean +/- SD) and generated a burst of spikes, with strong accommodation, to depolarizing current injection. Calcium-dependent low-frequency (1-8 Hz) membrane oscillations were often elicited by membrane depolarization (-53 +/- 8 mV). A low-threshold calcium conductance and an A-current were also identified. The mean input resistance of this neuronal type was 70 +/- 22 M omega. 3. Type II neurons (37%) fired spontaneously at the resting membrane level (-59 +/- 9 mV). Their repetitive firing (< or = 200 Hz) was very sensitive to the amplitude of injected current and showed weak accommodation. Sodium-dependent high-frequency (20-100 Hz) subthreshold membrane oscillations were often elicited by membrane depolarization. This neuronal type demonstrated a low-threshold calcium spike and had the highest input resistance (134 +/- 62 M omega) of the three neuron types. 4. Type III neurons (4%) did not fire spontaneously at the resting membrane level (-73 +/- 5 mV). Their action potentials were characterized by a long duration (2.3 +/- 0.6 ms). Repetitive firing elicited by depolarizing current injection showed weak or no accommodation. This neuronal type had an A-current and showed the lowest input resistance (52 +/- 35 M omega) of the three neuron types. 5. Stimulation of the caudoputamen evoked inhibitory postsynaptic potentials (IPSPs) in Type I and II neurons. In Type II neurons the IPSPs were usually followed by rebound firing. Excitatory postsynaptic potentials and antidromic responses were also elicited in some Type I and II neurons. The estimated conduction velocity of the striopallidal projection was < 1 m/s (Type I neurons, 0.49 +/- 0.37 m/s; Type II

  3. Optimal control approach to termination of re-entry waves in cardiac electrophysiology

    PubMed Central

    Nagaiah, Chamakuri; Kunisch, Karl; Plank, Gernot

    2014-01-01

    This work proposes an optimal control approach for the termination of re-entry waves in cardiac electrophysiology. The control enters as an extracellular current density into the bidomain equations which are well established model equations in the literature to describe the electrical behavior of the cardiac tissue. The optimal control formulation is inspired, in part, by the dynamical systems behavior of the underlying system of differential equations. Existence of optimal controls is established and the optimality system is derived formally. The numerical realization is described in detail and numerical experiments, which demonstrate the capability of influencing and terminating reentry phenomena, are presented. PMID:22684847

  4. Electrical storm: A clinical and electrophysiological overview

    PubMed Central

    Conti, Sergio; Pala, Salvatore; Biagioli, Viviana; Del Giorno, Giuseppe; Zucchetti, Martina; Russo, Eleonora; Marino, Vittoria; Dello Russo, Antonio; Casella, Michela; Pizzamiglio, Francesca; Catto, Valentina; Tondo, Claudio; Carbucicchio, Corrado

    2015-01-01

    Electrical storm (ES) is a clinical condition characterized by three or more ventricular arrhythmia episodes leading to appropriate implantable cardioverter-defibrillator (ICD) therapies in a 24 h period. Mostly, arrhythmias responsible of ES are multiple morphologies of monomorphic ventricular tachycardia (VT), but polymorphic VT and ventricular fibrillation can also result in ES. Clinical presentation is very dramatic in most cases, strictly related to the cardiac disease that may worsen electrical and hemodynamic decompensation. Therefore ES management is challenging in the majority of cases and a high mortality is the rule both in the acute and in the long-term phases. Different underlying cardiomyopathies provide significant clues into the mechanism of ES, which can arise in the setting of structural arrhythmogenic cardiomyopathies or rarely in patients with inherited arrhythmic syndrome, impacting on pharmacological treatment, on ICD programming, and on the opportunity to apply strategies of catheter ablation. This latter has become a pivotal form of treatment due to its high efficacy in modifying the arrhythmogenic substrate and in achieving rhythm stability, aiming at reducing recurrences of ventricular arrhythmia and at improving overall survival. In this review, the most relevant epidemiological and clinical aspects of ES, with regard to the acute and long-term follow-up implications, were evaluated, focusing on these novel therapeutic strategies of treatment. PMID:26413232

  5. Visualization of elusive structures using intracardiac echocardiography: Insights from electrophysiology

    PubMed Central

    Szili-Torok, T; McFadden, EP; Jordaens, LJ; Roelandt, JRTC

    2004-01-01

    Electrophysiological mapping and ablation techniques are increasingly used to diagnose and treat many types of supraventricular and ventricular tachycardias. These procedures require an intimate knowledge of intracardiac anatomy and their use has led to a renewed interest in visualization of specific structures. This has required collaborative efforts from imaging as well as electrophysiology experts. Classical imaging techniques may be unable to visualize structures involved in arrhythmia mechanisms and therapy. Novel methods, such as intracardiac echocardiography and three-dimensional echocardiography, have been refined and these technological improvements have opened new perspectives for more effective and accurate imaging during electrophysiology procedures. Concurrently, visualization of these structures noticeably improved our ability to identify intracardiac structures. The aim of this review is to provide electrophysiologists with an overview of recent insights into the structure of the heart obtained with intracardiac echocardiography and to indicate to the echo-specialist which structures are potentially important for the electrophysiologist. PMID:15253772

  6. Electrophysiological recordings from behaving animals--going beyond spikes.

    PubMed

    Chorev, Edith; Epsztein, Jérôme; Houweling, Arthur R; Lee, Albert K; Brecht, Michael

    2009-10-01

    Most of our current knowledge about the neural control of behavior is based on electrophysiology. Here we review advances and limitations of current electrophysiological recording techniques applied in behaving animals. Extracellular recording methods have improved with respect to sampling density and miniaturization, and our understanding of the nature of the recorded signals has advanced. Juxtacellular recordings have become increasingly popular as they allow identification of the recorded neurons. Juxtacellular recordings are relatively easy to apply in behaving animals and can be used to stimulate individual neurons. Methods for intracellular recordings in awake behaving animals also advanced, and it has become clear that long-duration intracellular recordings are possible even in freely moving animals. We conclude that the electrophysiological methods repertoire has greatly diversified in recent years and that the field has moved beyond what used to be a mere spike counting business.

  7. Electrophysiological properties of inferior olive neurons: A compartmental model.

    PubMed

    Schweighofer, N; Doya, K; Kawato, M

    1999-08-01

    As a step in exploring the functions of the inferior olive, we constructed a biophysical model of the olivary neurons to examine their unique electrophysiological properties. The model consists of two compartments to represent the known distribution of ionic currents across the cell membrane, as well as the dendritic location of the gap junctions and synaptic inputs. The somatic compartment includes a low-threshold calcium current (I(Ca_l)), an anomalous inward rectifier current (I(h)), a sodium current (I(Na)), and a delayed rectifier potassium current (I(K_dr)). The dendritic compartment contains a high-threshold calcium current (I(Ca_h)), a calcium-dependent potassium current (I(K_Ca)), and a current flowing into other cells through electrical coupling (I(c)). First, kinetic parameters for these currents were set according to previously reported experimental data. Next, the remaining free parameters were determined to account for both static and spiking properties of single olivary neurons in vitro. We then performed a series of simulated pharmacological experiments using bifurcation analysis and extensive two-parameter searches. Consistent with previous studies, we quantitatively demonstrated the major role of I(Ca_l) in spiking excitability. In addition, I(h) had an important modulatory role in the spike generation and period of oscillations, as previously suggested by Bal and McCormick. Finally, we investigated the role of electrical coupling in two coupled spiking cells. Depending on the coupling strength, the hyperpolarization level, and the I(Ca_l) and I(h) modulation, the coupled cells had four different synchronization modes: the cells could be in-phase, phase-shifted, or anti-phase or could exhibit a complex desynchronized spiking mode. Hence these simulation results support the counterintuitive hypothesis that electrical coupling can desynchronize coupled inferior olive cells.

  8. Serial Magnetization Transfer Imaging in Acute Optic Neuritis

    ERIC Educational Resources Information Center

    Hickman, S. J.; Toosy, A. T.; Jones, S. J.; Altmann, D. R.; Miszkiel, K. A.; MacManus, D. G.; Barker, G. J.; Plant, G. T.; Thompson, A. J.; Miller, D.H.

    2004-01-01

    In serial studies of multiple sclerosis lesions, reductions in magnetization transfer ratio (MTR) are thought to be due to demyelination and axonal loss, with later rises due to remyelination. This study followed serial changes in MTR in acute optic neuritis in combination with clinical and electrophysiological measurements to determine if the MTR…

  9. Electrophysiologic features of inherited demyelinating neuropathies: a reappraisal.

    PubMed

    Lewis, R A; Sumner, A J

    1999-09-14

    The observation that inherited demyelinating neuropathies tend to have uniform conduction slowing and acquired disorders (CIDP and variants) have nonuniform or multifocal slowing was made before the identification of genetic defects of specific myelin constituents that cause the different forms of Charcot-Marie-Tooth and other inherited disorders involving peripheral nerve myelin. It is becoming clear that the electrophysiologic aspects of these disorders are more complex than previously realized. We review the current information available on the electrophysiologic features of the inherited demyelinating neuropathies in hopes of clarifying the clinical electrodiagnostic features of these disorders as well as to shed light on the physiologic consequences of the different genetic mutations.

  10. Optrodes for combined optogenetics and electrophysiology in live animals

    PubMed Central

    Dufour, Suzie; De Koninck, Yves

    2015-01-01

    Abstract. Optical tissue properties limit visible light depth penetration in tissue. Because of this, the recent development of optogenetic tools was quickly followed by the development of light delivery devices for in vivo optogenetics applications. We summarize the efforts made in the last decade to design neural probes that combine conventional electrophysiological recordings and optical channel(s) for optogenetic activation, often referred to as optodes or optrodes. Several aspects including challenges for light delivery in living brain tissue, the combination of light delivery with electrophysiological recordings, probe designs, multimodality, wireless implantable system, and practical considerations guiding the choice of configuration depending on the questions one seeks to address are presented. PMID:26158014

  11. Quantitative comparison of cardiac ventricular myocyte electrophysiology and response to drugs in human and nonhuman species.

    PubMed

    O'Hara, Thomas; Rudy, Yoram

    2012-03-01

    Explanations for arrhythmia mechanisms at the cellular level are usually based on experiments in nonhuman myocytes. However, subtle electrophysiological differences between species may lead to different rhythmic or arrhythmic cellular behaviors and drug response given the nonlinear and highly interactive cellular system. Using detailed and quantitatively accurate mathematical models for human, dog, and guinea pig ventricular action potentials (APs), we simulated and compared cell electrophysiology mechanisms and response to drugs. Under basal conditions (absence of β-adrenergic stimulation), Na(+)/K(+)-ATPase changes secondary to Na(+) accumulation determined AP rate dependence for human and dog but not for guinea pig where slow delayed rectifier current (I(Ks)) was the major rate-dependent current. AP prolongation with reduction of rapid delayed rectifier current (I(Kr)) and I(Ks) (due to mutations or drugs) showed strong species dependence in simulations, as in experiments. For humans, AP prolongation was 80% following I(Kr) block. It was 30% for dog and 20% for guinea pig. Under basal conditions, I(Ks) block was of no consequence for human and dog, but for guinea pig, AP prolongation after I(Ks) block was severe. However, with β-adrenergic stimulation, I(Ks) played an important role in all species, particularly in AP shortening at fast rate. Quantitative comparison of AP repolarization, rate-dependence mechanisms, and drug response in human, dog, and guinea pig revealed major species differences (e.g., susceptibility to arrhythmogenic early afterdepolarizations). Extrapolation from animal to human electrophysiology and drug response requires great caution.

  12. Cardiac function in an endothermic fish: cellular mechanisms for overcoming acute thermal challenges during diving

    PubMed Central

    Shiels, H. A.; Galli, G. L. J.; Block, B. A.

    2015-01-01

    Understanding the physiology of vertebrate thermal tolerance is critical for predicting how animals respond to climate change. Pacific bluefin tuna experience a wide range of ambient sea temperatures and occupy the largest geographical niche of all tunas. Their capacity to endure thermal challenge is due in part to enhanced expression and activity of key proteins involved in cardiac excitation–contraction coupling, which improve cardiomyocyte function and whole animal performance during temperature change. To define the cellular mechanisms that enable bluefin tuna hearts to function during acute temperature change, we investigated the performance of freshly isolated ventricular myocytes using confocal microscopy and electrophysiology. We demonstrate that acute cooling and warming (between 8 and 28°C) modulates the excitability of the cardiomyocyte by altering the action potential (AP) duration and the amplitude and kinetics of the cellular Ca2+ transient. We then explored the interactions between temperature, adrenergic stimulation and contraction frequency, and show that when these stressors are combined in a physiologically relevant way, they alter AP characteristics to stabilize excitation–contraction coupling across an acute 20°C temperature range. This allows the tuna heart to maintain consistent contraction and relaxation cycles during acute thermal challenges. We hypothesize that this cardiac capacity plays a key role in the bluefin tunas' niche expansion across a broad thermal and geographical range. PMID:25540278

  13. Reversal of visual discrimination and visual acute extinction in cats with poor or limited early visual experience.

    PubMed

    Zernicki, B

    1997-01-01

    Transformation of visual instrumental conditioned reflexes rewarded with food was compared in cats binocularly deprived of pattern vision in the early period of life (BD cats), control cats reared also in the laboratory but with open eyes (C cats) and cats reared in normal environment (N cats). In Expt. I the cats were given 4 sequential reversal trainings of cross vs. disc discrimination and in Expt. II a response to a gate marked with a cross or a disc was submitted to 4 sequential acute extinctions and restorations. The results show that both visual deprivation and rearing in monotonous laboratory environment moderately affect transformation of associations between visual stimuli and hunger drive and instrumental responses. However, in BD cats transformation learning is less impaired than previously studied visual discrimination learning.

  14. Incidence and management of proven and probable fungal infections in patients with acute leukemia: a single center experience.

    PubMed

    Fanci, R; Casini, C; Leoni, F; Ciolli, S; Bosi, A

    2004-12-01

    The incidence of fungal infections and the role of liposomal amphotericin B (Ambisome) in proven and probable infections were evaluated in acute leukemic patients, intolerant to conventional amphotericin B. During 1999-2002, 307 febrile episodes occurred in 231 patients. Fungi were responsible for 3% of bloodstream infections. Ambisome was employed in 5 fungal sepsis (1 Candida albicans, 1 C. famata, 1 C. tropicalis, 1 C. krusei, 1 Geotrichum capitatum) 2 Aspergillosis, 2 probable fungal pneumonia cases. A favorable response was achieved in 78% of patients (4 fungemia, 2 aspergillosis, 1 probable), an unfavorable response in 1 C. krusei fungemia and in 1 probable pneumonia. Our antimicrobial pattern documented a high resistance rate to azoles. We concluded that Ambisome is an effective and well tolerated agent and its introduction has changed the outcome for many patients, although in some refractory diseases other strategies must be considered.

  15. Low-dose Ara-C in myelodysplastic syndromes and acute nonlymphoid leukemia. Experience with seven patients.

    PubMed

    Bruzzese, L; Abbadessa, A; Ottaiano, L; Arcidiacone, G

    1987-01-01

    Seven patients were treated with low dose Ara-C (LDAC). Five patients had acute nonlymphoid leukemia (ANLL), two patients had myelodisplastic syndrome (MDS): refractory anemia (RA) and refractory anemia with excess of blasts in transformation (RAEB-t). Ara-C treatment was given by s.c. injections at a dose of 10-11 mg/m2 every 12 h and only on two occasions by continuous infusion. No improvement, or limited improvement, was observed in five patients and they died of leukemia or of disease-related complications. Two patients with ANLL achieved remission: the first patient after bone marrow aplasia, the second without aplasia but with morphologic evidence of granulocytic differentiation of leukemic cells.

  16. The Use of Electrophysiology in the Study of Early Development

    ERIC Educational Resources Information Center

    Szucs, Denes

    2005-01-01

    Electrophysiology is a timely and important tool in the study of early cognitive development. This commentary polishes the definition of event-related potential (ERP) components; often interpreted as expressions of mental processes. Further, attention is drawn to time-frequency analysis of the electroencephalogram (EEG) which conveys much more…

  17. Should we perform systematic electrophysiological study in Steinert's disease?

    PubMed

    Fayssoil, Abdallah

    2008-10-18

    Myotonic dystrophy type 1 (Steinert's disease) is a multisystem disorder with autosomal dominant inheritance. This disease is associated with the presence of an abnormal expansion of a cytosine thymine-guanine (CTG) trinucleotide repeat on chromosome 19q13.3. Because of rhythmic complications, the place for systematic electrophysiological study (EPS) has to be discussed.

  18. Should we perform systematic electrophysiological study in Steinert's disease?

    PubMed Central

    Fayssoil, Abdallah

    2008-01-01

    Myotonic dystrophy type 1 (Steinert's disease) is a multisystem disorder with autosomal dominant inheritance. This disease is associated with the presence of an abnormal expansion of a cytosine thymine-guanine (CTG) trinucleotide repeat on chromosome 19q13.3. Because of rhythmic complications, the place for systematic electrophysiological study (EPS) has to be discussed. PMID:18928563

  19. Electrophysiological features of POEMS syndrome and chronic inflammatory demyelinating polyneuropathy.

    PubMed

    Guo, Xiuming; Qin, Xinyue; Zhang, Yuping; Huang, Cheng; Yu, Gang

    2014-04-01

    Polyneuropathy is often an initial manifestation of polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes (POEMS) syndrome and therefore this disorder is frequently misdiagnosed as chronic inflammatory demyelinating polyneuropathy (CIDP). We reviewed electrophysiological data in 20 patients with POEMS syndrome and 36 matched patients with CIDP to compare the electrophysiological features of POEMS syndrome and CIDP. Compared with CIDP controls, POEMS patients demonstrated (1) less prolonged distal motor latency and less reduced motor nerve and sensory nerve conduction velocities, (2) greater reduction of amplitudes of compound motor action potentials (CMAP) in distal stimulation, and similar reduction of amplitudes of CMAP in proximal stimulation, (3) similar reduction of amplitudes of sensory nerve action potentials (SNAP) in median and ulnar nerves, and a greater reduction of amplitudes of SNAP in tibial and peroneal nerves, (4) less temporal dispersion, (5) less frequent conduction block, (6) more frequent neurogenic injury in the muscles of the upper and lower limbs, and more frequent neurogenic injury in the muscles of the lower than upper limbs, (7) similar F wave and H reflex abnormalities, and (8) less frequent skin sympathetic response abnormalities. We concluded that before development of typical clinical manifestations, POEMS neuropathy can be distinguished from CIDP by neural electrophysiological examination. These electrophysiological features can be used for early diagnosis and initiating correct treatment of POEMS syndrome.

  20. Electrophysiological Signals of Familiarity and Recency in the Infant Brain

    ERIC Educational Resources Information Center

    Snyder, Kelly A.; Garza, John; Zolot, Liza; Kresse, Anna

    2010-01-01

    Electrophysiological work in nonhuman primates has established the existence of multiple types of signals in the temporal lobe that contribute to recognition memory, including information regarding a stimulus's relative novelty, familiarity, and recency of occurrence. We used high-density event-related potentials (ERPs) to examine whether young…

  1. The Electrophysiological Correlates of Scientific Innovation Induced by Heuristic Information

    ERIC Educational Resources Information Center

    Luo, Junlong; Du, Xiumin; Tang, Xiaochen; Zhang, Entao; Li, Haijiang; Zhang, Qinglin

    2013-01-01

    In this study, novel and old scientific innovations (NSI and OSI) were selected as materials to explore the electrophysiological correlates of scientific innovation induced by heuristic information. Using event-related brain potentials (ERPs) to do so, college students solved NSI problems (for which they did not know the answers) and OSI problems…

  2. Cardiac Electrophysiology: Normal and Ischemic Ionic Currents and the ECG

    ERIC Educational Resources Information Center

    Klabunde, Richard E.

    2017-01-01

    Basic cardiac electrophysiology is foundational to understanding normal cardiac function in terms of rate and rhythm and initiation of cardiac muscle contraction. The primary clinical tool for assessing cardiac electrical events is the electrocardiogram (ECG), which provides global and regional information on rate, rhythm, and electrical…

  3. Standardization of Electrophysiological Measures of Hearing in Marine Mammals

    DTIC Science & Technology

    2004-01-01

    modified for in-air testing of pinniped hearing. Two of three subjects involved in the study have been trained using operant conditioning and positive ... reinforcement techniques to voluntarily participate in electrophysiological testing procedures (i.e., enter the controlled acoustic environment of the

  4. Recanalization of Acute and Subacute Femoropopliteal Artery Occlusions with the Rotarex Catheter: One Year Follow-up, Single Center Experience

    SciTech Connect

    Duc, Sylvain R. Schoch, Eric; Pfyffer, Markus; Jenelten, Regula; Zollikofer, Christoph L.

    2005-06-15

    Purpose:To assess the efficacy and safety of a new rotational catheter for percutaneous removal of fresh and organized thrombi in the femoropopliteal artery.Methods:Forty-one limbs in 38 patients (age 56-90 years, mean 75.6 years) with acute, subacute or chronic femoropopliteal occlusions of 1-180 days' duration (mean 31.6 days) were treated with the Rotarex device. The Fontaine stage was mainly IIB (Rutherford 2-3, 22 patients) or III (Rutherford 4, 14 patients). The length of occlusion varied from 2 to 35 cm (mean 13.1 cm). After recanalization percutaneous transluminal angioplasty (PTA) was performed if there was a residual stenosis of >25%. Patients were followed up with color Doppler ultrasound at 48 hr and clinically with Doppler pressures and oscillometry at 3, 6, and 12 months.Results:After an average of two passages with the Rotarex catheter all but two limbs required PTA for residual stenosis >25%. Five patients needed additional stenting. Major complications were one groin hematoma requiring blood transfusion and one arteriovenous fistula spontaneously thrombosing after unsuccessful primary prolonged balloon dilation. Distal embolizations occurred in 10 patients; 6 clinically relevant emboli were aspirated. All occlusions were technically successfully recanalised there were 2 early reocclusions after 1 day and two at 2 weeks. Brachial-ankle indices improved from an average of 0.41 before to 0.93 after recanalization. Primary and secondary patency rates were 62% / 84% after 6 months and 39% / 68% after 1 year. The amputation-free survival at 12 months was 100%.Conclusion:The Rotarex mechanical thrombectomy device is an efficient, quick, easy to handle, and safe tool for the treatment of acute, subacute or even chronic peripheral arterial thromboembolic occlusions. It can be used for short or long occlusions with equal success, provided the obstruction is not heavily calcified and has been safely passed with a guidewire first.

  5. Laparoscopic ileocecal resection in acute and chronic presentations of Crohn’s disease. A single center experience

    PubMed Central

    COCORULLO, G.; TUTINO, R.; FALCO, N.; SALAMONE, G.; FONTANA, T.; LICARI, L.; GULOTTA, G.

    2016-01-01

    Introduction The terminal ileum is the most involved tract in Crohn’s disease. The obstruction in this location is the most frequent complication. Acute or chronic presentations can occur. Surgery finds a role in the management of chronic strictures and in acute clinical presentations with complications not improving with conservative therapy. Patients and methods We investigate the outcome of patients with obstruction of the ileo-cecal bowel tract laparoscopically managed. It was analyzed the average operative time (OT), the conversion rate and the occurrence of re-operation due to surgical complications. Results 21 patients underwent an ileocecal resection for complicated Crohn’s disease between January 2013 and December 2014. The admissions were performed in emergency in 42% of patients. The pre-intervention hospital stay was 5.8 (Sd 6.23). The mean operative time was 154 min (Sd 41). 28% of the procedures were converted to open surgery. The average hospital stay was 10 days (Sd 5) in uncomplicated patients. The morbidity rate was 28%. In 19% of cases a re-intervention was needed due to anastomotic leakage (3pts) and one hemoperitoneum for bleeding from the suture line. Discussion Laparoscopy seems an affordable technique in the management of obstructive pattern of Crohn’s disease. It should be the preferable approach in young patients that probably will be submitted to subsequent surgery for the same disease; in fact, the reduced adhesions formation provided by the less bowel manipulation make easy the subsequent access. Older patients had usually more post-operative morbidity and mortality mostly due to pre-existing conditions; if possible in these patients the treatment should be medical. PMID:28098059

  6. Pregnenolone sulphate enhances spatial orientation and object discrimination in adult male rats: evidence from a behavioural and electrophysiological study.

    PubMed

    Plescia, Fulvio; Sardo, Pierangelo; Rizzo, Valerio; Cacace, Silvana; Marino, Rosa Anna Maria; Brancato, Anna; Ferraro, Giuseppe; Carletti, Fabio; Cannizzaro, Carla

    2014-01-01

    Neurosteroids can alter neuronal excitability interacting with specific neurotransmitter receptors, thus affecting several functions such as cognition and emotionality. In this study we investigated, in adult male rats, the effects of the acute administration of pregnenolone-sulfate (PREGS) (10mg/kg, s.c.) on cognitive processes using the Can test, a non aversive spatial/visual task which allows the assessment of both spatial orientation-acquisition and object discrimination in a simple and in a complex version of the visual task. Electrophysiological recordings were also performed in vivo, after acute PREGS systemic administration in order to investigate on the neuronal activation in the hippocampus and the perirhinal cortex. Our results indicate that, PREGS induces an improvement in spatial orientation-acquisition and in object discrimination in the simple and in the complex visual task; the behavioural responses were also confirmed by electrophysiological recordings showing a potentiation in the neuronal activity of the hippocampus and the perirhinal cortex. In conclusion, this study demonstrates that PREGS systemic administration in rats exerts cognitive enhancing properties which involve both the acquisition and utilization of spatial information, and object discrimination memory, and also correlates the behavioural potentiation observed to an increase in the neuronal firing of discrete cerebral areas critical for spatial learning and object recognition. This provides further evidence in support of the role of PREGS in exerting a protective and enhancing role on human memory.

  7. Electrophysiological and clinical evaluation of the effects of transcutaneous electrical nerve stimulation on the spasticity in the hemiplegic stroke patients.

    PubMed

    Karakoyun, Ahmet; Boyraz, İsmail; Gunduz, Ramazan; Karamercan, Ayşe; Ozgirgin, Nese

    2015-11-01

    To investigate whether transcutaneous electrical nerve stimulation (TENS) mitigates the spasticity of hemiplegic stroke patients, as assessed by electrophysiological variables, and the effects, if any, on the clinical appearance of spasticity. [Subjects and Methods] Twenty-seven subjects who had acute hemiplegia and 24 healthy people as the control group, were enrolled in this study. Some of the acute cerebrovascular disease patients could walk. Subjects who did not have spasticity, who were taking antispasticity medicine, or had a previous episode of cerebrovascular disease were excluded. The walking speed of the patients was recorded before and after TENS. EMG examinations were performed on the healthy controls and in the affected side of the patients. A 30-minute single session of TENS was applied to lower extremity. At 10 minutes after TENS, the EMG examinations were repeated. [Results] A statistically significant decrease in the spasticity variables, and increased walking speed were found post-TENS. The lower M amplitude and higher H reflex amplitude, H/M maximum amplitude ratio, H slope, and H slope/M slope ratio on the spastic side were found to be statistically significant. [Conclusion] TENS application for hemiplegic patients with spastic lower extremities due to cerebrovascular disease resulted in marked improvement in clinical scales of spasticity and significant changes in the electrophysiological variables.

  8. Electrophysiology for biomedical engineering students: a practical and theoretical course in animal electrocorticography.

    PubMed

    Albarracín, Ana L; Farfán, Fernando D; Coletti, Marcos A; Teruya, Pablo Y; Felice, Carmelo J

    2016-09-01

    The major challenge in laboratory teaching is the application of abstract concepts in simple and direct practical lessons. However, students rarely have the opportunity to participate in a laboratory that combines practical learning with a realistic research experience. In the Biomedical Engineering career, we offer short and optional courses to complement studies for students as they initiate their Graduation Project. The objective of these theoretical and practical courses is to introduce students to the topics of their projects. The present work describes an experience in electrophysiology to teach undergraduate students how to extract cortical information using electrocorticographic techniques. Students actively participate in some parts of the experience and then process and analyze the data obtained with different signal processing tools. In postlaboratory evaluations, students described the course as an exceptional opportunity for students interested in following a postgraduate science program and fully appreciated their contents.

  9. An Association between Auditory-Visual Synchrony Processing and Reading Comprehension: Behavioral and Electrophysiological Evidence.

    PubMed

    Mossbridge, Julia; Zweig, Jacob; Grabowecky, Marcia; Suzuki, Satoru

    2017-03-01

    The perceptual system integrates synchronized auditory-visual signals in part to promote individuation of objects in cluttered environments. The processing of auditory-visual synchrony may more generally contribute to cognition by synchronizing internally generated multimodal signals. Reading is a prime example because the ability to synchronize internal phonological and/or lexical processing with visual orthographic processing may facilitate encoding of words and meanings. Consistent with this possibility, developmental and clinical research has suggested a link between reading performance and the ability to compare visual spatial/temporal patterns with auditory temporal patterns. Here, we provide converging behavioral and electrophysiological evidence suggesting that greater behavioral ability to judge auditory-visual synchrony (Experiment 1) and greater sensitivity of an electrophysiological marker of auditory-visual synchrony processing (Experiment 2) both predict superior reading comprehension performance, accounting for 16% and 25% of the variance, respectively. These results support the idea that the mechanisms that detect auditory-visual synchrony contribute to reading comprehension.

  10. Object-oriented approach to fast display of electrophysiological data under MS-windows.

    PubMed

    Marion-Poll, F

    1995-12-01

    Microcomputers provide neuroscientists an alternative to a host of laboratory equipment to record and analyze electrophysiological data. Object-oriented programming tools bring an essential link between custom needs for data acquisition and analysis with general software packages. In this paper, we outline the layout of basic objects that display and manipulate electrophysiological data files. Visual inspection of the recordings is a basic requirement of any data analysis software. We present an approach that allows flexible and fast display of large data sets. This approach involves constructing an intermediate representation of the data in order to lower the number of actual points displayed while preserving the aspect of the data. The second group of objects is related to the management of lists of data files. Typical experiments designed to test the biological activity of pharmacological products include scores of files. Data manipulation and analysis are facilitated by creating multi-document objects that include the names of all experiment files. Implementation steps of both objects are described for an MS-Windows hosted application.

  11. Assessment of the cellular and electrophysiological response of cardiomyocytes to radiation

    NASA Astrophysics Data System (ADS)

    Helm, Alexander; Ritter, Sylvia; Durante, Marco; Friess, Johannes; Thielemann, Christiane; Mr; Frank, Simon

    Cardiac disease is considered as a late effect resulting from an exposure during long-term space missions. Yet, the underlying mechanisms and the impact of radiation quality and dose are not well understood. To address this topic, we used cardiomyocytes derived from mouse embryonic stem cells (mESC) as a model system. This model has already been successfully used for cardiotoxicity screening of new drugs. Both, the cellular and electrophysiological response to X-ray irradiation were examined. Cellular endpoints such as the induction of micronuclei, apoptosis, number of binucleated cells and expression of connexin43 (Cx 43) were analyzed by standard techniques. For electrophysiological studies a microelectrode array (MEA) was used allowing non-invasive recordings of electrical signals such as signal amplitude and shape, beat rate and conduction velocity. Data analysis was performed using the MATLAB based software DrCell. As a first approach, cardiomyocytes were generated by differentiation of mESC via the formation of embryoid bodies. However, the system proved to be unsuitable due to large intra- and inter-sample variations. In consecutive experiments we used commercially available Cor.At cells, i.e. a pure culture of mESC derived cardiomyocytes. For the analysis of cellular and electrophysiological endpoints Cor.At cells were seeded onto chamber slides or MEA chips, respectively. Irradiation with 0.5 and 2 Gy X-rays (250 kV, 16 mA) was performed two days after seeding. At that time cardiomyocytes are electrically coupled through gap junctions and form a spontaneously beating network. Samples were examined up to four days after exposure. Analysis of the electrophysiological data revealed only minor differences between controls and X-irradiated samples indicating the functionality of cardiomyocytes is not within the dose range examined. Currently, further experiments are performed to statistically verify this finding. Additionally, the expression of Cx 43, a major

  12. Coronary Reconnection in Emergency “Conduit Operation” for Acute Type-A Aortic Dissection with Aortic Insufficiency: Experience with 24 Cases

    PubMed Central

    Massimo, Carlo G.; Presenti, Luigi F.; Favi, Piero P.; Duranti, Alberto; Poma, Alberto G.; Marranci, Pierluigi; Modiano, Claudio

    1987-01-01

    Twenty-four cases of acute type-A aortic dissection with aortic valvular insufficiency were treated in our institution by means of an emergency operation in which the aortic valve, ascending aorta, and aortic arch were resected and replaced with a valved conduit that had been lengthened with a tubular Dacron graft. The procedure included the use of deep hypothermia for cerebral protection, as well as extracorporeal circulation. Aortic resection was performed from the aortic valve to the origin of the descending thoracic aorta; the aortic graft was anastomosed proximally to the valve annulus and distally to the descending aorta. The carotid orifices were connected to the side of the graft in a single tissue button. The coronary arteries were then reconnected by means of double venous bypass grafts to the innominate artery, to allow for inclusion of the graft. Within 1 month after operation, four patients died of the consequences of dissection. Six months postoperatively, one patient succumbed to an infarction. Six months to 5 years after operation, the remaining 19 patients are still alive. On the basis of this experience, we believe that acute type-A aortic dissection with aortic valvular insufficiency should be treated during the first hours after the onset of symptoms. The above-described procedure proved effective in the control of bleeding, which is the major risk in emergency operations of this type. (Texas Heart Institute Journal 1987; 14:418-421) Images PMID:15227299

  13. Age-Related Changes in 1/f Neural Electrophysiological Noise.

    PubMed

    Voytek, Bradley; Kramer, Mark A; Case, John; Lepage, Kyle Q; Tempesta, Zechari R; Knight, Robert T; Gazzaley, Adam

    2015-09-23

    Aging is associated with performance decrements across multiple cognitive domains. The neural noise hypothesis, a dominant view of the basis of this decline, posits that aging is accompanied by an increase in spontaneous, noisy baseline neural activity. Here we analyze data from two different groups of human subjects: intracranial electrocorticography from 15 participants over a 38 year age range (15-53 years) and scalp EEG data from healthy younger (20-30 years) and older (60-70 years) adults to test the neural noise hypothesis from a 1/f noise perspective. Many natural phenomena, including electrophysiology, are characterized by 1/f noise. The defining characteristic of 1/f is that the power of the signal frequency content decreases rapidly as a function of the frequency (f) itself. The slope of this decay, the noise exponent (χ), is often <-1 for electrophysiological data and has been shown to approach white noise (defined as χ = 0) with increasing task difficulty. We observed, in both electrophysiological datasets, that aging is associated with a flatter (more noisy) 1/f power spectral density, even at rest, and that visual cortical 1/f noise statistically mediates age-related impairments in visual working memory. These results provide electrophysiological support for the neural noise hypothesis of aging. Significance statement: Understanding the neurobiological origins of age-related cognitive decline is of critical scientific, medical, and public health importance, especially considering the rapid aging of the world's population. We find, in two separate human studies, that 1/f electrophysiological noise increases with aging. In addition, we observe that this age-related 1/f noise statistically mediates age-related working memory decline. These results significantly add to this understanding and contextualize a long-standing problem in cognition by encapsulating age-related cognitive decline within a neurocomputational model of 1/f noise-induced deficits in

  14. Changes in the action potential and transient outward potassium current in cardiomyocytes during acute cardiac rejection in rats

    PubMed Central

    Luo, Wenqi; Jia, Yixin; Zheng, Shuai; Li, Yan; Han, Jie

    2017-01-01

    Background Acute cardiac rejection contributes to the changes in the electrophysiological properties of grafted hearts. However, the electrophysiological changes of cardiomyocytes during acute cardiac rejection are still unknown. An understanding of the electrophysiological mechanisms of cardiomyocytes could improve the diagnosis and treatment of acute cardiac rejection. So it is important to characterize the changes in the action potential (AP) and the transient outward potassium current (Ito) in cardiomyocytes during acute cardiac rejection. Methods Heterotopic heart transplantation was performed in allogeneic [Brown Norway (BN)-to-Lewis] and isogeneic (BN-to-BN) rats. Twenty models were established in each group. Ten recipients were sacrificed at the 2nd day and the other ten recipients were sacrificed at the 4th day after the operation in each group. Histopathological examinations of the grafted hearts were performed in half of the recipients in each group randomly. The other half of the grafted hearts were excised rapidly and enzymatically dissociated to obtain single cardiomyocytes. The AP and Ito current were recorded using the whole cell patch-clamp technique. Results Forty grafted hearts were successfully harvested and used in experiments. Histologic examination showed mild rejection at the 2nd day and moderate rejection at the 4th day in the allogeneic group after cardiac transplantation, while no evidence of histologic lesions of rejection were observed in the isogeneic group. Compared with the isogeneic group, the action potential duration (APD) of cardiomyocytes in the allogeneic group was significantly prolonged (APD90 was 49.28±5.621 mV in the isogeneic group and 88.08±6.445 mV in the allogeneic group at the 2nd day, P=0.0016; APD90 was 59.34±5.183 mV in the isogeneic group and 104.0±9.523 mV in the allogeneic group at the 4th day, P=0.0064). The current density of Ito was significantly decreased at the 4th day after cardiac transplantation

  15. Acute Appendicitis in Patients with Acute Leukemia

    PubMed Central

    Kim, Ki Up; Kim, Jin Kyeung; Won, Jong Ho; Hong, Dae Sik; Park, Hee Sook; Park, Kyeung Kyu

    1993-01-01

    The decision to operate for abdominal pain in patients with leukopenia can be exceedingly difficult. Surgical exploration may be the only effective way to differentiate acute appendicitis from other causes, but it involves considerable risk of infectious complications due to immunesuppression. Leukemic patients, who presented significant RLQ pain, had been indicated for operation, despite having advanced disease or having had received chemotherapy or steroids. Four adult leukemia patients, complicated by acute appendictis, were reviewed. Two patients were in induction chemotherapy, one receiving salvage chemotheapy due to relapse and the other was in conservative treatment. Two patients were acute myelocytic leukemia (AML), one had acute lymphocytic leukemia (ALL), and the other had aleukemic leukemia. All patients underwent appendectomy and recovered without complication. Our experience supports the theory that the surgical management of appendicitis in acute leukemia is the most effective way, in spite of leukopenia. PMID:8268146

  16. Electrophysiological assessment of water stress in fruit-bearing woody plants.

    PubMed

    Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

    2014-06-15

    Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a

  17. Post-conditioning experience with acute or chronic inflammatory pain reduces contextual fear conditioning in the rat.

    PubMed

    Johnston, Ian N; Maier, Steven F; Rudy, Jerry W; Watkins, Linda R

    2012-01-15

    There is evidence that pain can impact cognitive function in people. The present study evaluated whether Pavlovian fear conditioning in rats would be reduced if conditioning were followed by persistent inflammatory pain induced by a subcutaneous injection of dilute formalin or complete Freund's adjuvant (CFA) on the dorsal lumbar surface of the back. Formalin-induced pain specifically impaired contextual fear conditioning but not auditory cue conditioning (Experiment 1A). Moreover, formalin pain only impaired contextual fear conditioning if it was initiated within 1h of conditioning and did not have a significant effect if initiated 2, 8 or 32 h after (Experiments 1A and 1B). Experiment 2 showed that formalin pain initiated after a session of context pre-exposure reduced the ability of that pre-exposure to facilitate contextual fear when the rat was limited to a brief exposure to the context during conditioning. Similar impairments in context- but not CS-fear conditioning were also observed if the rats received an immediate post-conditioning injection with CFA (Experiment 3). Finally, we confirmed that formalin and CFA injected s.c. on the back induced pain-indicative behaviours, hyperalgesia and allodynia with a similar timecourse to intraplantar injections (Experiment 4). These results suggest that persistent pain impairs learning in a hippocampus-dependent task, and may disrupt processes that encode experiences into long-term memory.

  18. Electrophysiological Correlates of Stimulus Equivalence Processes

    ERIC Educational Resources Information Center

    Haimson, Barry; Wilkinson, Krista M.; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J.

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g.,…

  19. The Earliest Electrophysiological Correlate of Visual Awareness?

    ERIC Educational Resources Information Center

    Koivisto, Mika; Lahteenmaki, Mikko; Sorensen, Thomas Alrik; Vangkilde, Signe; Overgaard, Morten; Revonsuo, Antti

    2008-01-01

    To examine the neural correlates and timing of human visual awareness, we recorded event-related potentials (ERPs) in two experiments while the observers were detecting a grey dot that was presented near subjective threshold. ERPs were averaged for conscious detections of the stimulus (hits) and nondetections (misses) separately. Our results…

  20. Acute fulminant neuropathy in a patient with Churg-Strauss syndrome.

    PubMed Central

    Ng, K. K.; Yeung, H. M.; Loo, K. T.; Chan, H. M.; Wong, C. K.; Li, P. C.

    1997-01-01

    We report a patient with an acute neuropathy initially mimicking Guillain-Barré syndrome, both clinically and electrophysiologically. Persistent eosinophilia, positive antineutrophil cytoplasmic antibody and eosinophilic vasculitis in sural nerve biopsy later confirmed Churg-Strauss syndrome. Since vasculitic neuropathy can present in an acute and fulminant form, the role of early antibody testing and sural nerve biopsy in atypical cases of acute neuropathy is emphasized. Images Figure PMID:9156128

  1. Pattern and Outcome of Acute Disseminated Encephalomyelitis (ADEM) in Children: Experience in a Tertiary Center, Upper Egypt

    PubMed Central

    Sadek, Abdelrahim Abdrabou; Mohamed, Mostafa Ashry; Abou-Taleb, Ashraf; Mohammed, Marwa Ibrahim

    2016-01-01

    Introduction Acute disseminated encephalomyelitis (ADEM) is an immune mediated disease of the brain. Although it occurs in all ages, most reported cases are in children and adolescents. The aims of this study were to study the clinical pattern and outcome of ADEM in children in a tertiary center in Upper Egypt and to determine the effect of combined use of steroids and IVIg on outcome. Methods This observational study was carried out from January 2014 through December 2014 in the Pediatric Department of Sohag University Hospital (Egypt). All children diagnosed as ADEM during a one year period were included in this study. The treatments used were IV methylprednisolone followed by oral prednisone taper and intravenous immunoglobulin for severe cases. All studied cases were followed up and reevaluated at three months and six months. We used SPSS version 10 and Chi Square, Spearman’s test and t-test for data analysis. Results Eighteen children were included in this study (10 males and 8 females), the average age was 5.5 ± 0.9 years. Prodroma was found in 72.22% of the cases while the main complaint was encephalopathy (83.33%) followed by seizures (11.11%). The neurological findings were convulsions in 83.33%, quadriparesis (33.33%), hemiparesis (33.33), bladder involvement (both retention and incontinence) in 61.11%, and cranial nerve affection (11.11%). Demyelination patches were multifocal in 50%, mainly subcortical in 27.78%. Intelligence quotient (IQ) assessment after 6 months follow up showed that 50% were below average, 25% had mild MR while neurological evaluation showed that 75% of our patients were completely cured. The predictors of better outcome were; children related to the age group (1–4 years) (p = 0.01), children with higher GCS (6–14) (p = 0.01), and children who received steroids on the first day of symptoms and intravenous immunoglobulin in the first week (p = 0.03). Conclusion The clinical pattern of acute disseminated encephalomyelitis is

  2. The experiences of female spouses of survivors of acute myocardial infarction: a pilot study of Lebanese-born women in south-western Sydney, Australia.

    PubMed

    Daly, J; Jackson, D; Davidson, P M; Wade, V; Chin, C; Brimelow, V

    1998-12-01

    Lebanese migrants form a significant proportion of the population in southwestern Sydney (SWS), and in New South Wales, Australia. This pilot study was undertaken in south-western Sydney, a rapidly expanding and socioeconomically disadvantaged region, to explore the experiences of English speaking women of Lebanese origin whose spouses had recently experienced an acute myocardial infarction (AMI). Semi-structured interviews were conducted with seven Lebanese-born women at 2- and 4-week intervals, following the discharge of their husbands from hospital. Qualitative analysis of narrative text revealed four distinct themes. These were: struggle to resolve distress; intensive monitoring of the AMI survivor; searching for avenues of support; and reflecting on the future. Study findings are discussed in relation to the literature. Implications for nursing practice and research are drawn from study findings.

  3. Clinical and electrophysiological features of Guillain-Barré syndrome in Iran.

    PubMed

    Yadegari, Samira; Kazemi, Neda; Nafissi, Shahriar

    2014-09-01

    We evaluated the clinical and electrophysiological characteristics of 121 consecutive patients admitted with Guillain-Barré syndrome (GBS) to a tertiary referral hospital in Tehran, Iran, from 1997 to 2007. The mean age of patients was 38.9 (standard deviation 19.7) years. The predominant subtype of GBS was the demyelinating form. Miller Fisher syndrome was present in 3.3% of patients. There was no significant seasonal clustering among the three subtypes, but axonal variants tend to occur in summer. In contrast with other subtypes, the majority of patients with acute motor-sensory axonal neuropathy (AMSAN) were female (72.3%). AMSAN patients also had significantly longer hospitalization time (p=0.002) and intensive care unit (ICU) admission (p=0.017), while none of the acute motor axonal neuropathy patients needed ICU admission. Involvement of cranial nerves and symmetry of signs were significantly detected in the demyelinating variant (p=0.021 and p=0.040, respectively). The overall mortality was 3.3%.

  4. Evolution from electrophysiologic to hemodynamic monitoring: the story of left atrial and pulmonary artery pressure monitors

    PubMed Central

    Mooney, Deirdre M.; Fung, Erik; Doshi, Rahul N.; Shavelle, David M.

    2015-01-01

    Heart failure (HF) is a costly, challenging and highly prevalent medical condition. Hospitalization for acute decompensation is associated with high morbidity and mortality. Despite application of evidence-based medical therapies and technologies, HF remains a formidable challenge for virtually all healthcare systems. Repeat hospitalizations for acute decompensated HF (ADHF) can have major financial impact on institutions and resources. Early and accurate identification of impending ADHF is of paramount importance yet there is limited high quality evidence or infrastructure to guide management in the outpatient setting. Historically, ADHF was identified by physical exam findings or invasive hemodynamic monitoring during a hospital admission; however, advances in medical microelectronics and the advent of device-based diagnostics have enabled long-term ambulatory monitoring of HF patients in the outpatient setting. These monitors have evolved from piggybacking on cardiac implantable electrophysiologic devices to standalone implantable hemodynamic monitors that transduce left atrial or pulmonary artery pressures as surrogate measures of left ventricular filling pressure. As technology evolves, devices will likely continue to miniaturize while their capabilities grow. An important, persistent challenge that remains is developing systems to translate the large volumes of real-time data, particularly data trends, into actionable information that leads to appropriate, safe and timely interventions without overwhelming outpatient cardiology and general medical practices. Future directions for implantable hemodynamic monitors beyond their utility in heart failure may include management of other major chronic diseases such as pulmonary hypertension, end stage renal disease and portal hypertension. PMID:26500556

  5. Physiotherapists' Perceptions of and Experiences with the Discharge Planning Process in Acute-Care General Internal Medicine Units in Ontario

    PubMed Central

    Uyeno, Jennifer; Heck, Carol S.

    2014-01-01

    ABSTRACT Purpose: To examine discharge planning of patients in general internal medicine units in Ontario acute-care hospitals from the perspective of physiotherapists. Methods: A cross-sectional study using an online questionnaire was sent to participants in November 2011. Respondents' demographic characteristics and ranking of factors were analyzed using descriptive statistics; t-tests were performed to determine between-group differences (based on demographic characteristics). Responses to open-ended questions were coded to identify themes. Results: Mobility status was identified as the key factor in determining discharge readiness; other factors included the availability of social support and community resources. While inter-professional communication was identified as important, processes were often informal. Discharge policies, timely availability of other discharge options, and pressure for early discharge were identified as affecting discharge planning. Respondents also noted a lack of training in discharge planning; accounts of ethical dilemmas experienced by respondents supported these themes. Conclusions: Physiotherapists consider many factors beyond the patient's physical function during the discharge planning process. The improvement of team communication and resource allocation should be considered to deal with the realities of discharge planning. PMID:25125778

  6. Acute vasoreactivity test results in severe pulmonary hypertension patients with chronic obstructive pulmonary disease: our experience with 29 cases

    PubMed Central

    Asker, Selvi; Asker, Muntecep

    2015-01-01

    Aim The aim of the current study is to evaluate acute vasoreactivity test (AVT) results in severe pulmonary hypertension patients with chronic obstructive pulmonary disease and to compare the demographical, clinical, and laboratory variables in positive and negative cases. Methods This retrospective, clinical study was performed on 29 cases in the departments of cardiology and chest diseases of our tertiary care center. AVT was positive in 12 (41.4%) cases and negative in 17 (58.6%) cases. Demographical variables, cardiopulmonary indicators, and laboratory findings were compared in these two subgroups. Results The mean age was 62.3±7.8 years for AVT negative group, while it was 64.8±7.3 years in AVT positive group (P=0.38). Except for the changes in systolic, diastolic, and mean pulmonary arterial pressures before and after iloprost administration, there were no statistically significant differences regarding any of the parameters under investigation in both groups. Conclusion Despite the high rate of positivity for AVT in severe pulmonary hypertension patients with chronic obstructive pulmonary disease, none of the variables under investigation displayed a noteworthy difference between AVT negative and positive groups. Identification of factors likely to influence AVT results is important for establishment of appropriate treatment protocols especially for AVT negative cases. PMID:26064044

  7. Nurses experiences of delivering care in acute inpatient mental health settings: A narrative synthesis of the literature.

    PubMed

    Wyder, Marianne; Ehrlich, Carolyn; Crompton, David; McArthur, Leianne; Delaforce, Caroline; Dziopa, Fiona; Ramon, Shulamit; Powell, Elizabeth

    2017-03-14

    Inpatient psychiatric care requires a balance between working with consumers' priorities and goals, managing expectations of the community, legal, professional and service responsibilities. In order to improve service delivery within acute mental health units, it is important to understand the constraints and facilitating factors for good care. We conducted a systematic narrative synthesis, where findings of qualitative studies are synthesised to generate new insights. 21 articles were identified. Our results show that personal qualities, professional skills as well as environmental factors all influence the ability to provide recovery focused care. Three overarching themes which either facilitated or hindered were identified. These included: (i) Complexity of the nursing role (clinical care; practical and emotional support: advocacy and education; enforcing aspects of the Mental Health Act. and, maintaining ward safety); (ii) Constraining factors (operational barriers; change in patient characteristic; and competing understandings of care); and (iii) Facilitating factors (ward factors; nursing tools; nurse characteristics; approach to people; approach to work and ability to self-care). We suggest that the therapeutic use of self is central to the provision of recovery oriented care. However person-centred practice can be fragile and fluid and a compassionate system of support is needed to enable an understanding of context and self. It is critical to have a work environment which fosters hope and optimism and is supportive of autonomy, ensures workload balance, and is safe.

  8. Pregnancy-related acute kidney injury: experience of the nephrology unit at the university hospital of fez, morocco.

    PubMed

    Arrayhani, Mohamed; El Youbi, Randa; Sqalli, Tarik

    2013-01-01

    Introduction. Acute kidney injury (PRAKI) continues to be common in developing countries. The aim of this paper is to study AKI characteristics in pregnancy and identify the factors related to the unfavorable evolution. Methods. This prospective study was conducted in the University Hospital Hassan II of Fez, Morocco, from February 01, 2011 to January 31, 2012. All patients presenting PRAKI were included. Results. 37 cases of PRAKI were listed. Their ages varied from 20 to 41 years old, with an average of 29.03 ± 6.3 years and an average parity of 1.83. High blood pressure was the most common symptom (55.6%). Thirty-nine percent were oliguric. PRAKI occurred during the 3rd trimester in 66.6% of the cases and 25% of the cases in the postpartum. Hemodialysis was necessary in 16.2% of cases. The main causes were preeclampsia, hemorrhagic shocks, and functional, respectively, in 66.6%, 25%, and 8.3% of the cases. The outcome was favorable, with a complete renal function recovery for 28 patients. Poor prognosis was related to two factors: age over 38 years and advanced stage of AKI according to RIFLE classification. Conclusion. Prevention of PRAKI requires an improvement of the sanitary infrastructures with the implementation of an obligatory prenatal consultation.

  9. Misdiagnosis of Acute Appendicitis in Children Attending the Emergency Department: The Experience of a Large, Tertiary Care Pediatric Hospital.

    PubMed

    Galai, Tut; Beloosesky, Osnat Zmora; Scolnik, Dennis; Rimon, Ayelet; Glatstein, Miguel

    2017-04-01

    Background Missed appendicitis is a frequent cause of professional liability for emergency department (ED) physicians. Our objective was to assess and compare the presentations of patients in whom the diagnosis of appendicitis was missed with those in whom it was correctly diagnosed on their first ED visit and to identify the clinical features that characterized the two groups. Methods This study is a retrospective review of all ED children with proven appendicitis between January 2010 and December 2013. Historical, clinical, and laboratory features of patients missed and correctly diagnosed during their first ED visit were compared. The literature on this subject was also reviewed. Results A total of 400 patients were included in this study. Fifteen (3.75%) patients were considered to be misdiagnoses, the most common misdiagnosis being acute gastroenteritis (26.6%). Thirty-three percent of misdiagnosed patients had undergone an ultrasound compared with 87% of correctly diagnosed patients (p < 0.05). Conclusion Our incidence of missed appendicitis compares favorably with the 6.9 to 27.6% incidence reported in the literature. Our relatively low incidence may be a result of medical practice, especially during night shifts, and the availability of ultrasound 24 hours a day.

  10. Importance of root HTO uptake in controlling land-surface tritium dynamics after an-acute HT deposition: a numerical experiment.

    PubMed

    Ota, Masakazu; Nagai, Haruyasu; Koarashi, Jun

    2012-07-01

    To investigate the role of belowground root uptake of tritiated water (HTO) in controlling land-surface tritium (T) dynamics, a sophisticated numerical model predicting tritium behavior in an atmosphere-vegetation-soil system was developed, and numerical experiments were conducted using the model. The developed model covered physical tritiated hydrogen (HT) transport in a multilayered atmosphere and soil, as well as microbial oxidation of HT to HTO in the soil, and it was incorporated into a well-established HTO-transfer organically bound tritium (OBT)-formation model. The model performance was tested through the simulation of an existing HT-release experiment. Numerical experiments involving a hypothetical acute HT exposure to a grassland field with a range of rooting depths showed that the HTO release from the leaves to the atmosphere, driven by the root uptake of the deposited HTO, can exceed the HTO evaporation from the ground surface to the atmosphere when root water absorption preferentially occurs beneath the ground surface. Such enhanced soil-leaf-atmosphere HTO transport, caused by the enhanced root HTO uptake, increased HTO concentrations in both the surface atmosphere and in the cellular water of the leaf. Consequently, leaf OBT assimilation calculated for shallow rooting depths increased by nearly an order of magnitude compared to that for large rooting depths.

  11. Factors that influence clinicians' decisions to offer intravenous alteplase in acute ischemic stroke patients with uncertain treatment indication: Results of a discrete choice experiment.

    PubMed

    De Brún, Aoife; Flynn, Darren; Ternent, Laura; Price, Christopher I; Rodgers, Helen; Ford, Gary A; Rudd, Matthew; Lancsar, Emily; Simpson, Stephen; Teah, John; Thomson, Richard G

    2017-01-01

    Background Treatment with intravenous alteplase for eligible patients with acute ischemic stroke is underused, with variation in treatment rates across the UK. This study sought to elucidate factors influencing variation in clinicians' decision-making about this thrombolytic treatment. Methods A discrete choice experiment using hypothetical patient vignettes framed around areas of clinical uncertainty was conducted with UK-based clinicians. Mixed logit regression analyses were conducted on the data. Results A total of 138 clinicians completed the discrete choice experiment. Seven patient factors were individually predictive of increased likelihood of immediately offering IV alteplase (compared to reference levels in brackets): stroke onset time 2 h 30 min [50 min]; pre-stroke dependency mRS 3 [mRS 4]; systolic blood pressure 185 mm/Hg [140 mm/Hg]; stroke severity scores of NIHSS 5 without aphasia, NIHSS 14 and NIHSS 23 [NIHSS 2 without aphasia]; age 85 [68]; Afro-Caribbean [white]. Factors predictive of withholding treatment with IV alteplase were: age 95 [68]; stroke onset time of 4 h 15 min [50 min]; severe dementia [no memory problems]; SBP 200 mm/Hg [140 mm/Hg]. Three clinician-related factors were predictive of an increased likelihood of offering IV alteplase (perceived robustness of the evidence for IV alteplase; thrombolyzing more patients in the past 12 months; and high discomfort with uncertainty) and one with a decreased likelihood (high clinician comfort with treating patients outside the licensing criteria). Conclusions Both patient- and clinician-related factors have a major influence on the use of alteplase to treat patients with acute ischemic stroke. Clinicians' views of the evidence, comfort with uncertainty and treating patients outside the license criteria are important factors to address in programs that seek to reduce variation in care quality regarding treatment with IV alteplase. Further research is needed to further understand

  12. Cystitis - acute

    MedlinePlus

    Uncomplicated urinary tract infection; UTI - acute cystitis; Acute bladder infection; Acute bacterial cystitis ... cause. Menopause also increases the risk for a urinary tract infection. The following also increase your chances of having ...

  13. Electrophysiological Correlates of Stimulus Equivalence Processes

    PubMed Central

    Haimson, Barry; Wilkinson, Krista M; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g., wrist, corn). For pairs of both types, event-related cortical potentials were recorded during and immediately after the presentation of the second word. The obtained waveforms differentiated these two types of pairs. For the unrelated pairs, the waveforms were significantly more negative about 400 ms after the second word was presented, thus replicating the “N400” phenomenon of the cognitive neuroscience literature. In addition, there was a strong positive-tending wave form difference post-stimulus presentation (peaked at about 500 ms) that also differentiated the unrelated from related stimulus pairs. In Experiment 2, the procedures were extended to study arbitrary stimulus–stimulus relations established via matching-to-sample training. Participants were experimentally naïve adults. Sample stimuli (Set A) were trigrams, and comparison stimuli (Sets B, C, D, E, and F) were nonrepresentative forms. Behavioral tests evaluated potentially emergent equivalence relations (i.e., BD, DF, CE, etc.). All participants exhibited classes consistent with the arbitrary matching training. They were also exposed also to an event-related potential procedure like that used in Experiment 1. Some received the ERP procedure before equivalence tests and some after. Only those participants who received ERP procedures after equivalence tests exhibited robust N400 differentiation initially. The positivity observed in Experiment 1 was absent for all participants. These results support speculations that equivalence tests may provide contextual support for the formation of equivalence classes including those that emerge gradually during testing

  14. Electrophysiology-Based Assays to Detect Subtype-Selective Modulation of Human Nicotinic Acetylcholine Receptors

    PubMed Central

    Kirsch, Glenn E.; Fedorov, Nikolai B.; Kuryshev, Yuri A.; Liu, Zhiqi; Orr, Michael S.

    2016-01-01

    Abstract The Family Smoking Prevention and Tobacco Control Act of 2009 (Public Law 111-31) gave the US Food and Drug Administration (FDA) the responsibility for regulating tobacco products. Nicotine is the primary addictive component of tobacco and its effects can be modulated by additional ingredients in manufactured products. Nicotine acts by mimicking the neurotransmitter acetylcholine on neuronal nicotinic acetylcholine receptors (nAChRs), which function as ion channels in cholinergic modulation of neurotransmission. Subtypes within the family of neuronal nAChRs are defined by their α- and β-subunit composition. The subtype-selective profiles of tobacco constituents are largely unknown, but could be essential for understanding the physiological effects of tobacco products. In this report, we report the development and validation of electrophysiology-based high-throughput screens (e-HTS) for human nicotinic subtypes, α3β4, α3β4α5, α4β2, and α7 stably expressed in Chinese Hamster Ovary cells. Assessment of agonist sensitivity and acute desensitization gave results comparable to those obtained by conventional manual patch clamp electrophysiology assays. The potency of reference antagonists for inhibition of the receptor channels and selectivity of positive allosteric modulators also were very similar between e-HTS and conventional manual patch voltage clamp data. Further validation was obtained in pilot screening of a library of FDA-approved drugs that identified α7 subtype-selective positive allosteric modulation by novel compounds. These assays provide new tools for profiling of nicotinic receptor selectivity. PMID:27505073

  15. Safety and Effectiveness of Drip, Ship, and Retrieve Paradigm for Acute Ischemic Stroke: a Single Center Experience

    PubMed Central

    HIYAMA, Nagayasu; YOSHIMURA, Shinichi; SHIRAKAWA, Manabu; UCHIDA, Kazutaka; OKI, Yoshiharu; SHINDO, Seigo; TOKUDA, Kou

    2016-01-01

    This study analyzed the efficacy and safety of the “drip, ship, and retrieve (DSR)” approach used to improve patient access to thrombectomy for acute stroke. Methods: The study participants were 45 patients who underwent thrombectomy following intravenous tissue plasminogen activator between September 2013 and August 2015. Patients were divided into two groups according to whether they were transferred from another hospital (DSR group; n = 33) or were brought in directly (Direct group; n = 12). The two groups were compared based on their baseline characteristics, time from stroke onset to reperfusion, outcome, and adverse events. Results: There were no significant differences in baseline characteristics. Time from onset until admission to our facility was significantly shorter in the Direct group (56.9 min) than in the DSR group (163.5 min) (P <0.0001). Conversely, time from arrival at the hospital to arterial puncture was significantly shorter in the DSR group (25.0 min) than in the Direct group (109.5 min) (P <0.0001). Time from onset to reperfusion did not differ significantly between the groups. There was no significant difference in patient outcomes, with a modified Rankin scale score of 0–2 (44.8% in DSR group versus 48.7% in Direct group). Moreover, there was no difference in the incidence of adverse events. Discussion: Despite the time required to transfer patients in the DSR group between hospitals, reducing the time from arrival until commencement of endovascular therapy meant that the time from onset to reperfusion was approximately equivalent to that of the Direct group. Conclusion: Time-saving measures need to be taken by both the transferring and receiving hospitals in DSR paradigm. PMID:27432512

  16. Corticosteroid and cyclophosphamide in acute exacerbation of idiopathic pulmonary fibrosis: a single center experience and literature review.

    PubMed

    Novelli, Luca; Ruggiero, Roberto; De Giacomi, Federica; Biffi, Alice; Faverio, Paola; Bilucaglia, Luca; Gamberini, Silvia; Messinesi, Grazia; Pesci, Alberto

    2016-12-23

    Acute Exacerbation (AEx) is a frequent and severe complication of Idiopathic Pulmonary Fibrosis (IPF). In the absence of consensus regarding treatment, studies evaluating the efficacy of specific therapies, such as corticosteroids and immunosuppresant agents, are needed. In this case series we evaluated the outcome in terms of survival of intravenous pulse doses of high-dose corticosteroid (methylprednisolone 1000 mg per day for 3 consecutive days) followed by montlhy cyclophosphamide administration (maximum 6 doses) in a cohort of patients with AEx-IPF referred to the Respiratory Unit, San Gerardo University Hospital, Monza, Italy, from 2009 to 2013. A total of 11 patients (7 males, median age 65 years) were enrolled. A median of five monthly pulse doses of cyclophosphamide were administered, with four patients receiving all 6 doses. Four patients died before completion. Three patients developed adverse events. Overall survival at 3 months was 73%, at 6 months 63%, at 12 months 55%, at 18 months 45% and at 2 years 27%. In-hospital mortality was 9%. Causes of death were: six respiratory failures from disease progression, one lung cancer and one breast cancer. Two patients received lung transplantation and were excluded from the Kaplan-Meier analysis. In conclusion, combined intravenous pulse doses of high-dose corticosteroid and cyclophosphamide could be a reasonable add-on therapy for AEx-IPF, considering the few side effects and safe profile. A complete and rapid diagnostic work-up associated to the proper management (e.g. support of respiratory failure with non-invasive ventilation) in the right setting, may also have a positive effect on patients' outcome.

  17. Acidemia in severe acute cardiogenic pulmonary edema treated with noninvasive pressure support ventilation: a single-center experience.

    PubMed

    Lazzeri, Chiara; Gensini, Gian F; Picariello, Claudio; Attanà, Paola; Mattesini, Alessio; Chiostri, Marco; Valente, Serafina

    2015-09-01

    In clinical practice, acidotic patients with acute cardiogenic pulmonary edema (ACPE) are commonly considered more severe in comparison with nonacidotic patients, and data on the outcome of these patients treated with noninvasive pressure support ventilation (NIV) are lacking.The present investigation was aimed at assessing whether acidosis on admission (pH < 7.35) was associated with adverse outcome in 65 consecutive patients with ACPE treated with NIV and admitted to our Intensive Cardiac Care Unit (ICCU).In our population, 28 patients were acidotic (28 of 65, 43.1%), whereas 41 patients were not (37 of 65, 56.9%). According to the Repeated Measures General Linear Model, pCO2 values significantly changed throughout the 2-h NIV treatment (P = 0.019) in both groups (P = 0001). In acidotic patients, pCO2 significantly decreased (51.9 ± 15.3 → 47.0 ± 12.8 → 44.8 ± 12.7), whereas they increased in the nonacidotic subgroup (36.8 ± 6.5 → 36.9 ± 7.2 → 37.6 ± 6.4). No difference was observed in intubation rate between acidotic (eight patients, 28.6%) and nonacidotic patients (12 patients, 32.4%) (P = 0.738). In-ICCU mortality rate did not differ between (13 patients, 35.1%) and nonacidotic patients (nine patients, 32.1%) (P = 0.801).Our data strongly suggest that in patients with severe ACPE treated with NIV, the presence of acidosis is not associated with adverse outcomes (early mortality and intubation rates) in these patients.

  18. Influence of obestatin on the gastric longitudinal smooth muscle from mice: mechanical and electrophysiological studies.

    PubMed

    Squecco, Roberta; Garella, Rachele; Francini, Fabio; Baccari, Maria Caterina

    2013-11-01

    Obestatin is a hormone released from the stomach deriving from the same peptide precursor as ghrelin. It is known to act as an anorectic hormone decreasing food intake, but contrasting results have been reported about the effects of obestatin on gastrointestinal motility. The aim of the present study was to investigate whether this peptide may act on the gastric longitudinal smooth muscle by using a combined mechanical and electrophysiological approach. When fundal strips from mice were mounted in organ baths for isometric recording of the mechanical activity, obestatin caused a tetrodotoxin-insensitive decrease of the basal tension and a reduction in amplitude of the neurally induced cholinergic contractile responses, even in the presence of the nitric oxide synthesis inhibitor N(G)-nitro-l-arginine. Obestatin reduced the amplitude of the response to the ganglionic stimulating agent dimethylphenyl piperazinium iodide but did not influence that to methacholine. In nonadrenergic, noncholinergic conditions, obestatin still decreased the basal tension of the preparations without influencing the neurally induced relaxant responses. For comparison, in circular fundal strips, obestatin had no effects. Notably, in the longitudinal antral ones, obestatin only caused a decrease of the basal tension. Electrophysiological experiments, performed by a single microelectrode inserted in a gastric longitudinal smooth muscle cell, showed that obestatin had similar effects in fundal and antral preparations: it decreased the resting specific membrane conductance, inhibited Ca(2+) currents, and positively shifted their voltage threshold of activation. In conclusion, the present results indicate that obestatin influences gastric smooth muscle exerting site-specific effects.

  19. A reconfigurable visual-programming library for real-time closed-loop cellular electrophysiology.

    PubMed

    Biró, István; Giugliano, Michele

    2015-01-01

    Most of the software platforms for cellular electrophysiology are limited in terms of flexibility, hardware support, ease of use, or re-configuration and adaptation for non-expert users. Moreover, advanced experimental protocols requiring real-time closed-loop operation to investigate excitability, plasticity, dynamics, are largely inaccessible to users without moderate to substantial computer proficiency. Here we present an approach based on MATLAB/Simulink, exploiting the benefits of LEGO-like visual programming and configuration, combined to a small, but easily extendible library of functional software components. We provide and validate several examples, implementing conventional and more sophisticated experimental protocols such as dynamic-clamp or the combined use of intracellular and extracellular methods, involving closed-loop real-time control. The functionality of each of these examples is demonstrated with relevant experiments. These can be used as a starting point to create and support a larger variety of electrophysiological tools and methods, hopefully extending the range of default techniques and protocols currently employed in experimental labs across the world.

  20. Simulations of Complex and Microscopic Models of Cardiac Electrophysiology Powered by Multi-GPU Platforms

    PubMed Central

    Gouvêa de Barros, Bruno; Sachetto Oliveira, Rafael; Meira, Wagner; Lobosco, Marcelo; Weber dos Santos, Rodrigo

    2012-01-01

    Key aspects of cardiac electrophysiology, such as slow conduction, conduction block, and saltatory effects have been the research topic of many studies since they are strongly related to cardiac arrhythmia, reentry, fibrillation, or defibrillation. However, to reproduce these phenomena the numerical models need to use subcellular discretization for the solution of the PDEs and nonuniform, heterogeneous tissue electric conductivity. Due to the high computational costs of simulations that reproduce the fine microstructure of cardiac tissue, previous studies have considered tissue experiments of small or moderate sizes and used simple cardiac cell models. In this paper, we develop a cardiac electrophysiology model that captures the microstructure of cardiac tissue by using a very fine spatial discretization (8 μm) and uses a very modern and complex cell model based on Markov chains for the characterization of ion channel's structure and dynamics. To cope with the computational challenges, the model was parallelized using a hybrid approach: cluster computing and GPGPUs (general-purpose computing on graphics processing units). Our parallel implementation of this model using a multi-GPU platform was able to reduce the execution times of the simulations from more than 6 days (on a single processor) to 21 minutes (on a small 8-node cluster equipped with 16 GPUs, i.e., 2 GPUs per node). PMID:23227109

  1. A reconfigurable visual-programming library for real-time closed-loop cellular electrophysiology

    PubMed Central

    Biró, István; Giugliano, Michele

    2015-01-01

    Most of the software platforms for cellular electrophysiology are limited in terms of flexibility, hardware support, ease of use, or re-configuration and adaptation for non-expert users. Moreover, advanced experimental protocols requiring real-time closed-loop operation to investigate excitability, plasticity, dynamics, are largely inaccessible to users without moderate to substantial computer proficiency. Here we present an approach based on MATLAB/Simulink, exploiting the benefits of LEGO-like visual programming and configuration, combined to a small, but easily extendible library of functional software components. We provide and validate several examples, implementing conventional and more sophisticated experimental protocols such as dynamic-clamp or the combined use of intracellular and extracellular methods, involving closed-loop real-time control. The functionality of each of these examples is demonstrated with relevant experiments. These can be used as a starting point to create and support a larger variety of electrophysiological tools and methods, hopefully extending the range of default techniques and protocols currently employed in experimental labs across the world. PMID:26157385

  2. A computational model of Purkinje fibre single cell electrophysiology: implications for the long QT syndrome

    PubMed Central

    Sampson, K J; Iyer, V; Marks, A R; Kass, R S

    2010-01-01

    Computer modelling has emerged as a particularly useful tool in understanding the physiology and pathophysiology of cardiac tissues. Models of ventricular, atrial and nodal tissue have evolved and include detailed ion channel kinetics and intercellular Ca2+ handling. Purkinje fibre cells play a central role in the electrophysiology of the heart and in the genesis of cardiac arrhythmias. In this study, a new computational model has been constructed that incorporates the major membrane currents that have been isolated in recent experiments using Purkinje fibre cells. The model, which integrates mathematical models of human ion channels based on detailed biophysical studies of their kinetic and voltage-dependent properties, recapitulates distinct electrophysiological characteristics unique to Purkinje fibre cells compared to neighbouring ventricular myocytes. These characteristics include automaticity, hyperpolarized voltage range of the action potential plateau potential, and prolonged action potential duration. Simulations of selective ion channel blockade reproduce responses to pharmacological challenges characteristic of isolated Purkinje fibres in vitro, and importantly, the model predicts that Purkinje fibre cells are prone to severe arrhythmogenic activity in patients harbouring long QT syndrome 3 but much less so for other common forms of long QT. This new Purkinje cellular model can be a useful tool to study tissue-specific drug interactions and the effects of disease-related ion channel dysfunction on the cardiac conduction system. PMID:20498233

  3. Electrophysiological Responses in the Ventral Temporal Cortex During Reading of Numerals and Calculation.

    PubMed

    Hermes, Dora; Rangarajan, Vinitha; Foster, Brett L; King, Jean-Remi; Kasikci, Itir; Miller, Kai J; Parvizi, Josef

    2017-01-01

    Recent evidence suggests that specific neuronal populations in the ventral temporal cortex show larger electrophysiological responses to visual numerals compared with morphologically similar stimuli. This study investigates how these responses change from simple reading of numerals to the active use of numerals in an arithmetic context. We recorded high-frequency broadband (HFB) signals, a reliable measure for local neuronal population activity, while 10 epilepsy patients implanted with subdural electrodes performed separate numeral reading and calculation tasks. We found that calculation increased activity in the posterior inferior temporal gyrus (ITG) with a factor of approximately 1.5 over the first 500 ms of calculation, whereas no such increase was noted for reading numerals without calculation or reading and judging memory statements. In a second experiment conducted in 2 of the same subjects, we show that HFB responses increase in a systematic manner when the single numerals were presented successively in a calculation context: The HFB response in the ITG, to the second and third numerals (i.e., b and c in a + b = c), was approximately 1.5 times larger than the responses to the first numeral (a). These results provide electrophysiological evidence for modulation of local neuronal population responses to visual stimuli based on increasing task demands.

  4. Electrophysiologic characteristics of diverse accessory pathway locations of antidromic reciprocating tachycardia.

    PubMed

    Luria, D M; Chugh, S S; Munger, T M; Friedman, P A; Rea, R F; Packer, D L; Jahangir, A; Hammill, S C; Shen, W K

    2000-12-15

    This study assessed antidromic reciprocating tachycardia (ART) in patients with paraseptal accessory pathways (APs). Previous clinical experience suggests that paraseptal APs are unable to serve as the anterograde limb during ART. Based on the reentry wavelength concept, we hypothesized that anatomic location of a paraseptal AP may not preclude occurrence of ART. If wavelength criteria were met due to prolonged conduction time retrogradely in the atrioventricular node or anterogradely in the AP, ART may be sustained. All patients who had ART in the electrophysiologic laboratory at our institution (1991 to 1998) were studied. Based on fluoroscopically guided electrophysiologic mapping and radiofrequency ablation, AP location was classified as paraseptal, posterior, or lateral. Conduction time and refractoriness measurements were made for all components of the ART circuit. Of 24 patients with ART, 5 (21%) had ART utilizing a paraseptal AP. Anterograde conduction time through the AP and retrograde atrioventricular nodal conduction time were significantly longer in patients with paraseptal versus lateral pathways. Isoproterenol was required for ART induction in 38% of patients with a posterior AP, 36% with lateral AP location, but not in patients with a paraseptal AP. There were no significant differences in tachycardia cycle length or refractoriness of anterograde and/or retrograde components of the macroreentry circuit between the 3 pathway locations. Thus, ART can occur in patients with a paraseptal AP. Slower anterograde pathway conduction, or retrograde atrioventricular nodal conduction renders the wavelength critical for completion of the antidromic re-entrant circuit.

  5. Electrophysiological and amperometric evidence that modafinil blocks the dopamine uptake transporter to induce behavioral activation.

    PubMed

    Federici, M; Latagliata, E C; Rizzo, F R; Ledonne, A; Gu, H H; Romigi, A; Nisticò, R; Puglisi-Allegra, S; Mercuri, N B

    2013-11-12

    Although the wake-promoting drug modafinil has been shown to bind quite exclusively to the dopamine transporter (DAT), its action in the brain has been thought to be partially independent from the facilitation of the dopaminergic signals. Here we used electrophysiological and amperometric techniques to investigate the effects of modafinil on the dopaminergic neurons of the substantia nigra pars compacta (SNpc) and on the synaptic overflow of dopamine in the dorsal striatum from the sliced tissue of wild-type and cocaine-insensitive genetically modified mice (DAT-CI). Moreover, we examined the consequences of modafinil administration on the locomotor behavior of wild-type and DAT-CI mice. In in vitro experiments, modafinil inhibited the spontaneous firing discharge of the dopaminergic neurons. More consistently, it potentiated firing inhibition and the membrane responses caused by exogenously applied dopamine on these cells. Furthermore, it augmented the stimulus-evoked outflow of DA in the striatum. Noteworthy, modafinil caused locomotor activation in wild-type mice. On the other hand, neither the electrophysiological nor the behavioral effects of modafinil were detected in DAT-CI animals. These results demonstrate that modafinil potentiates brain dopaminergic signals via DAT inhibition by acting at the same binding site of cocaine. Therefore, this mechanism of action explains most of the pharmacological properties of this compound in the clinical setting.

  6. Nanomaterial-Enabled Dry Electrodes for Electrophysiological Sensing: A Review

    NASA Astrophysics Data System (ADS)

    Yao, Shanshan; Zhu, Yong

    2016-04-01

    Long-term, continuous, and unsupervised tracking of physiological data is becoming increasingly attractive for health/wellness monitoring and ailment treatment. Nanomaterials have recently attracted extensive attention as building blocks for flexible/stretchable conductors and are thus promising candidates for electrophysiological electrodes. Here we provide a review on nanomaterial-enabled dry electrodes for electrophysiological sensing, focusing on electrocardiography (ECG). The dry electrodes can be classified into contact surface electrodes, contact-penetrating electrodes, and noncontact capacitive electrodes. Different types of electrodes including their corresponding equivalent electrode-skin interface models and the sources of the noise are first introduced, followed by a review on recent developments of dry ECG electrodes based on various nanomaterials, including metallic nanowires, metallic nanoparticles, carbon nanotubes, and graphene. Their fabrication processes and performances in terms of electrode-skin impedance, signal-to-noise ratio, resistance to motion artifacts, skin compatibility, and long-term stability are discussed.

  7. Resuscitation great. Luigi Galvani and the foundations of electrophysiology.

    PubMed

    Cajavilca, Christian; Varon, Joseph; Sternbach, George L

    2009-02-01

    Luigi Galvani became one of the greatest scientists of the 18th century with his research and the development of his theory on animal electricity. His work was appreciated by many scientists. Nevertheless, it gave rise to one of the most passionate scientific debates in history when Alessandro Volta postulated that Galvani had confused intrinsic animal electricity with small currents produced by metals. This debate would result in the creation of electrophysiology, electromagnetism, electrochemistry and the electrical battery. Galvani responded to each of the postulated theories of Volta giving irrefutable proof of the involvement of electricity in the contraction of muscles. However, his work was subsequently abandoned and silenced for many years but his ideas and theories were finally confirmed by the creation of new instruments and the interest of new scientists who helped position Galvani as the father of electrophysiology.

  8. Data integration: Combined Imaging and Electrophysiology data in the cloud

    PubMed Central

    Kini, Lohith G.; Davis, Kathryn A.; Wagenaar, Joost B.

    2015-01-01

    There has been an increasing effort to correlate electrophysiology data with imaging in patients with refractory epilepsy over recent years. IEEG.org provides a free-access, rapidly growing archive of imaging data combined with electrophysiology data and patient metadata. It currently contains over 1200 human and animal datasets, with multiple data modalities associated with each dataset (neuroimaging, EEG, EKG, de-identified clinical and experimental data, etc.). The platform is developed around the concept that scientific data sharing requires a flexible platform that allows sharing of data from multiple file-formats. IEEG.org provides high and low-level access to the data in addition to providing an environment in which domain experts can find, visualize, and analyze data in an intuitive manner. Here, we present a summary of the current infrastructure of the platform, available datasets and goals for the near future. PMID:26044858

  9. Zebrafish heart as a model for human cardiac electrophysiology.

    PubMed

    Vornanen, Matti; Hassinen, Minna

    2016-01-01

    The zebrafish (Danio rerio) has become a popular model for human cardiac diseases and pharmacology including cardiac arrhythmias and its electrophysiological basis. Notably, the phenotype of zebrafish cardiac action potential is similar to the human cardiac action potential in that both have a long plateau phase. Also the major inward and outward current systems are qualitatively similar in zebrafish and human hearts. However, there are also significant differences in ionic current composition between human and zebrafish hearts, and the molecular basis and pharmacological properties of human and zebrafish cardiac ionic currents differ in several ways. Cardiac ionic currents may be produced by non-orthologous genes in zebrafish and humans, and paralogous gene products of some ion channels are expressed in the zebrafish heart. More research on molecular basis of cardiac ion channels, and regulation and drug sensitivity of the cardiac ionic currents are needed to enable rational use of the zebrafish heart as an electrophysiological model for the human heart.

  10. The need for plant electro-physiology

    NASA Astrophysics Data System (ADS)

    Gorgolewski, S.

    The already experimentaly evidenced existance of electrotropism for some plant species permits me to propose to extend these studies. Electrotropism is not well defined in plant physiology handbooks. There is a confusion of current and electric field which leads to communication problems between biologists and physicists. The electric field E, is measured in units of volts/metre=newtons/coulomb. We do not attach any wires to the plant leaves but subject them to the electric field. The plant distords the electrical field lines which in turn modify the shape of the plant. It has been verified in fitotron experiments that the direction and strength of the E vector relative to the gravitational force has different effects on plant growth. The natural fair weather global value of E is close to 130 V/m with positive charges in the air and negative on the ground. The most important results are: fields of (1.6 kV/m) enhance plant growth. Reversed fields overwhelm the gravitational field and plants grow towards the grownd. Horizontal E also enhances the plant growth in the horizontal direction ignoring the gravity. It shows that we can restore the directional orientation for plants in the absence of gravity by means of electrotropism. This is an important result for the plant growth in micro-gravity, basic advantage for long duration space fligths for raising edible crops for the vegetarian crew. It has the advantage of selecting in laboratory environment the plants which are suitable for space applications. The use of electic fields in ground based and space plant cultivation opens up important applications based on these novel trends also in modern greenhouses including the Biosphere 2. In addition to the fitotron experiments we have also studied plant growth in natural and modified natural electrical field environment. Two pioneering papers describing the above mentioned results and their possible ground based and space applications are cited as well as several

  11. Temporal and comparative outcomes of cardiac electrophysiology abstracts.

    PubMed

    Wong, Christopher X; Sun, Michelle T; Cheng, Yi Han; Dang, Jerry; Barlow, David S; Chia, Nicholas H; Wong, Nicole X; Wong, Michelle X; Lau, Dennis H; Brooks, Anthony G; Roberts-Thomson, Kurt C; Sanders, Prashanthan

    2013-07-15

    Although conferences are important vehicles for discussing scientific findings, the translation of presented research into peer-reviewed manuscripts is a crucial subsequent step in the research process. Given the evolving subspecialization of cardiology, we sought to characterize the temporal and comparative outcomes of abstracts presented at a subspecialty cardiac electrophysiology conference. Abstracts presented at the Heart Rhythm Society conference (1994 through 2006; HRS abstracts) and abstracts presented at the American Heart Association conference (2003; AHA abstracts) were studied. Subsequent publications, impact factors, and citation rates were determined. A total of 3,850 HRS and 1,000 AHA abstracts were studied. More human abstracts were presented at HRS than AHA (p <0.05). Compared with HRS abstracts, more AHA abstracts were published (p <0.001) and had higher impact factors and citation rates (p <0.001 for both). These differences were attributable in part to the greater proportion of human HRS abstracts. Compared with HRS abstracts, electrophysiology-related AHA abstracts were published less (p <0.001), and these publications had similar impact factors (p = 0.38) although greater citation rates (p = 0.001). The number and publication rate of HRS abstracts increased over the 15-year period, as did their publication impact factors and citation rates (p <0.001 for all). In conclusion, there are significant differences between AHA and HRS abstracts. Although AHA abstracts were more likely to be published overall, the publication rate and impact of electrophysiology abstracts presented at both a subspecialty (HRS) and a major cardiovascular conference (AHA) were comparable. There has also been a growth in the number and impact of cardiac electrophysiology abstracts presented at HRS in recent years.

  12. Space Motion Sickness and Stress Training Simulator using Electrophysiological Biofeedback

    NASA Astrophysics Data System (ADS)

    Gaudeau, C.; Golding, J. F.; Thevot, F.; Lucas, Y.; Bobola, P.; Thouvenot, J.

    2005-06-01

    An important problem in manned spaceflight is the nausea that typically appears during the first 3 days and then disappears after 5 days. Methods of detecting changes in electrophysiological signals are being studied in order to reduce susceptibility to space motion sickness through biofeedback training, and for the early detection of nausea during EVA. A simulator would allow subjects to control their body functions and to use biofeedback to control space motion sickness and stress.

  13. EARLY REARING EXPERIENCE IS ASSOCIATED WITH VASOPRESSIN IMMUNOREACTIVITY BUT NOT REACTIVITY TO AN ACUTE NON-SOCIAL STRESSOR IN THE PRAIRIE VOLE

    PubMed Central

    Perkeybile, Allison M.; Bales, Karen L.

    2015-01-01

    The early life experiences of an organism have the potential to alter their developmental trajectories. Perhaps one of the most powerful influences during this period is the parent-offspring relationship. Previous work in several mammalian species has demonstrated that parental care in early life and specifically maternal behavior can influence several adult outcomes in offspring, including affiliative and aggressive behavior, parental behavior, hypothalamic-pituitary-adrenal (HPA) functioning and risk of psychopathology. We have previously demonstrated that naturally occurring variation in the type and amount of care given to offspring in a biparental species, the prairie vole (Microtus ochrogaster), is related to social, anxiety-like, aggressive behaviors as well as HPA response to chronic and acute social stressors. Here we aim to determine the effects of early biparental care on HPA functioning and the interaction between early care and later reactivity to a forced swim test, an acute non-social stressor. Behavior during the swim test as well as several indicators of HPA activity, including plasma corticosterone (CORT), corticotropin releasing hormone immunoreactivity (CRH-ir), and vasopressin immunoreactivity (AVP-ir) were measured. Results here indicate an effect of early experience on AVP-ir but not CRH-ir or plasma CORT. There were no differences in CORT levels between high-contact (HC) and low-contact (LC) males or females for either control animals or after a swim stressor. CRH-ir was higher in the central amygdala following a swim test but was not influenced by early care. However, AVP-ir was not influenced by exposure to a swim stressor but was affected by early parental care in a sex-dependent manner. Female HC offspring had increased AVP-ir in the SON while HC male offspring had decreased AVP-ir in the PVN compared to their LC counterparts. The differential response of CRH and AVP to early experience and later stress, and the lack of an interaction

  14. Computerized clinical decision support for the early recognition and management of acute kidney injury: a qualitative evaluation of end-user experience

    PubMed Central

    Kanagasundaram, Nigel S.; Bevan, Mark T.; Sims, Andrew J.; Heed, Andrew; Price, David A.; Sheerin, Neil S.

    2016-01-01

    Background Although the efficacy of computerized clinical decision support (CCDS) for acute kidney injury (AKI) remains unclear, the wider literature includes examples of limited acceptability and equivocal benefit. Our single-centre study aimed to identify factors promoting or inhibiting use of in-patient AKI CCDS. Methods Targeting medical users, CCDS triggered with a serum creatinine rise of ≥25 μmol/L/day and linked to guidance and test ordering. User experience was evaluated through retrospective interviews, conducted and analysed according to Normalization Process Theory. Initial pilot ward experience allowed tool refinement. Assessments continued following CCDS activation across all adult, non-critical care wards. Results Thematic saturation was achieved with 24 interviews. The alert was accepted as a potentially useful prompt to early clinical re-assessment by many trainees. Senior staff were more sceptical, tending to view it as a hindrance. ‘Pop-ups’ and mandated engagement before alert dismissal were universally unpopular due to workflow disruption. Users were driven to close out of the alert as soon as possible to review historical creatinines and to continue with the intended workflow. Conclusions Our study revealed themes similar to those previously described in non-AKI settings. Systems intruding on workflow, particularly involving complex interactions, may be unsustainable even if there has been a positive impact on care. The optimal balance between intrusion and clinical benefit of AKI CCDS requires further evaluation. PMID:26798462

  15. Retrospective checking of compliance with practice guidelines for acute stroke care: a novel experiment using openEHR’s Guideline Definition Language

    PubMed Central

    2014-01-01

    Background Providing scalable clinical decision support (CDS) across institutions that use different electronic health record (EHR) systems has been a challenge for medical informatics researchers. The lack of commonly shared EHR models and terminology bindings has been recognised as a major barrier to sharing CDS content among different organisations. The openEHR Guideline Definition Language (GDL) expresses CDS content based on openEHR archetypes and can support any clinical terminologies or natural languages. Our aim was to explore in an experimental setting the practicability of GDL and its underlying archetype formalism. A further aim was to report on the artefacts produced by this new technological approach in this particular experiment. We modelled and automatically executed compliance checking rules from clinical practice guidelines for acute stroke care. Methods We extracted rules from the European clinical practice guidelines as well as from treatment contraindications for acute stroke care and represented them using GDL. Then we executed the rules retrospectively on 49 mock patient cases to check the cases’ compliance with the guidelines, and manually validated the execution results. We used openEHR archetypes, GDL rules, the openEHR reference information model, reference terminologies and the Data Archetype Definition Language. We utilised the open-sourced GDL Editor for authoring GDL rules, the international archetype repository for reusing archetypes, the open-sourced Ocean Archetype Editor for authoring or modifying archetypes and the CDS Workbench for executing GDL rules on patient data. Results We successfully represented clinical rules about 14 out of 19 contraindications for thrombolysis and other aspects of acute stroke care with 80 GDL rules. These rules are based on 14 reused international archetypes (one of which was modified), 2 newly created archetypes and 51 terminology bindings (to three terminologies). Our manual compliance checks for

  16. Moderate injury in motor-sensory cortex causes behavioral deficits accompanied by electrophysiological changes in mice adulthood.

    PubMed

    Ouyang, Wei; Yan, Qichao; Zhang, Yu; Fan, Zhiheng

    2017-01-01

    Moderate traumatic brain injury (TBI) in children often happen when there's a sudden blow to the frontal bone, end with long unconscious which can last for hours and progressive cognitive deficits. However, with regard to the influences of moderate TBI during children adulthood, injury-induced alterations of locomotive ability, long-term memory performance, and hippocampal electrophysiological firing changes have not yet been fully identified. In this study, lateral fluid percussion (LFP) method was used to fabricate moderate TBI in motor and somatosensory cortex of the 6-weeks-old mice. The motor function, learning and memory function, extracellular CA1 neural spikes were assessed during acute and subacute phase. Moreover, histopathology was performed on day post injury (DPI) 16 to evaluate the effect of TBI on tissue and cell morphological changes in cortical and hippocampal CA1 subregions. After moderate LFP injury, the 6-weeks-old mice showed severe motor deficits at the early stage in acute phase but gradually recovered later during adulthood. At the time points in acute and subacute phase after TBI, novel object recognition (NOR) ability and spatial memory functions were consistently impaired in TBI mice; hippocampal firing frequency and burst probability were hampered. Analysis of the altered burst firing shows a clear hippocampal theta rhythm drop. These electrophysiological impacts were associated with substantially lowered NOR preference as compared to the sham group during adulthood. These results suggest that moderate TBI introduced at motorsenory cortex in 6-weeks-old mice causes obvious motor and cognitive deficits during their adulthood. While the locomotive ability progressively recovers, the cognitive deficits persisted while the mice mature as adult mice. The cognitive deficits may be attributed to the general suppressing of whole neural network, which could be labeled by marked reduction of excitability in hippocampal CA1 subregion.

  17. Moderate injury in motor-sensory cortex causes behavioral deficits accompanied by electrophysiological changes in mice adulthood

    PubMed Central

    Yan, Qichao; Zhang, Yu; Fan, Zhiheng

    2017-01-01

    Moderate traumatic brain injury (TBI) in children often happen when there’s a sudden blow to the frontal bone, end with long unconscious which can last for hours and progressive cognitive deficits. However, with regard to the influences of moderate TBI during children adulthood, injury-induced alterations of locomotive ability, long-term memory performance, and hippocampal electrophysiological firing changes have not yet been fully identified. In this study, lateral fluid percussion (LFP) method was used to fabricate moderate TBI in motor and somatosensory cortex of the 6-weeks-old mice. The motor function, learning and memory function, extracellular CA1 neural spikes were assessed during acute and subacute phase. Moreover, histopathology was performed on day post injury (DPI) 16 to evaluate the effect of TBI on tissue and cell morphological changes in cortical and hippocampal CA1 subregions. After moderate LFP injury, the 6-weeks-old mice showed severe motor deficits at the early stage in acute phase but gradually recovered later during adulthood. At the time points in acute and subacute phase after TBI, novel object recognition (NOR) ability and spatial memory functions were consistently impaired in TBI mice; hippocampal firing frequency and burst probability were hampered. Analysis of the altered burst firing shows a clear hippocampal theta rhythm drop. These electrophysiological impacts were associated with substantially lowered NOR preference as compared to the sham group during adulthood. These results suggest that moderate TBI introduced at motorsenory cortex in 6-weeks-old mice causes obvious motor and cognitive deficits during their adulthood. While the locomotive ability progressively recovers, the cognitive deficits persisted while the mice mature as adult mice. The cognitive deficits may be attributed to the general suppressing of whole neural network, which could be labeled by marked reduction of excitability in hippocampal CA1 subregion. PMID

  18. Functional identification of islet cell types by electrophysiological fingerprinting

    PubMed Central

    Zhang, Quan; Vergari, Elisa; Kellard, Joely A.; Rodriguez, Blanca; Ashcroft, Frances M.; Rorsman, Patrik

    2017-01-01

    The α-, β- and δ-cells of the pancreatic islet exhibit different electrophysiological features. We used a large dataset of whole-cell patch-clamp recordings from cells in intact mouse islets (N = 288 recordings) to investigate whether it is possible to reliably identify cell type (α, β or δ) based on their electrophysiological characteristics. We quantified 15 electrophysiological variables in each recorded cell. Individually, none of the variables could reliably distinguish the cell types. We therefore constructed a logistic regression model that included all quantified variables, to determine whether they could together identify cell type. The model identified cell type with 94% accuracy. This model was applied to a dataset of cells recorded from hyperglycaemic βV59M mice; it correctly identified cell type in all cells and was able to distinguish cells that co-expressed insulin and glucagon. Based on this revised functional identification, we were able to improve conductance-based models of the electrical activity in α-cells and generate a model of δ-cell electrical activity. These new models could faithfully emulate α- and δ-cell electrical activity recorded experimentally. PMID:28275121

  19. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons

    NASA Astrophysics Data System (ADS)

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-04-01

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven’t been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries.

  20. Atrial Electrophysiological Remodeling and Fibrillation in Heart Failure

    PubMed Central

    Pandit, Sandeep V.; Workman, Antony J.

    2016-01-01

    Heart failure (HF) causes complex, chronic changes in atrial structure and function, which can cause substantial electrophysiological remodeling and predispose the individual to atrial fibrillation (AF). Pharmacological treatments for preventing AF in patients with HF are limited. Improved understanding of the atrial electrical and ionic/molecular mechanisms that promote AF in these patients could lead to the identification of novel therapeutic targets. Animal models of HF have identified numerous changes in atrial ion currents, intracellular calcium handling, action potential waveform and conduction, as well as expression and signaling of associated proteins. These studies have shown that the pattern of electrophysiological remodeling likely depends on the duration of HF, the underlying cardiac pathology, and the species studied. In atrial myocytes and tissues obtained from patients with HF or left ventricular systolic dysfunction, the data on changes in ion currents and action potentials are largely equivocal, probably owing mainly to difficulties in controlling for the confounding influences of multiple variables, such as patient’s age, sex, disease history, and drug treatments, as well as the technical challenges in obtaining such data. In this review, we provide a summary and comparison of the main animal and human electrophysiological studies to date, with the aim of highlighting the consistencies in some of the remodeling patterns, as well as identifying areas of contention and gaps in the knowledge, which warrant further investigation. PMID:27812293

  1. A model of electrophysiological heterogeneity in periglomerular cells

    PubMed Central

    Sethupathy, Praveen; Rubin, Daniel B.; Li, Guoshi; Cleland, Thomas A.

    2013-01-01

    Olfactory bulb (OB) periglomerular (PG) cells are heterogeneous with respect to several features, including morphology, connectivity, patterns of protein expression, and electrophysiological properties. However, these features rarely correlate with one another, suggesting that the differentiating properties of PG cells may arise from multiple independent adaptive variables rather than representing discrete cell classes. We use computational modeling to assess this hypothesis with respect to electrophysiological properties. Specifically, we show that the heterogeneous electrophysiological properties demonstrated in PG cell recordings can be explained solely by differences in the relative expression levels of ion channel species in the cell, without recourse to modifying channel kinetic properties themselves. This PG cell model can therefore be used as the basis for diverse cellular and network-level analyses of OB computations. Moreover, this simple basis for heterogeneity contributes to an emerging hypothesis that glomerular-layer interneurons may be better described as a single population expressing distributions of partially independent, potentially plastic properties, rather than as a set of discrete cell classes. PMID:23637658

  2. Electrophysiological characterization of Nsc-34 cell line using Microelectrode Array.

    PubMed

    Sabitha, K R; Sanjay, D; Savita, B; Raju, T R; Laxmi, T R

    2016-11-15

    Neurons communicate with each other through intricate network to evolve higher brain functions. The electrical activity of the neurons plays a crucial role in shaping the connectivity. With motor neurons being vulnerable to neurodegenerative diseases, understanding the electrophysiological properties of motor neurons is the need of the hour, in order to comprehend the impairment of connectivity in these diseases. NSC-34 cell line serves as an excellent model to study the properties of motor neurons as they express Choline acetyltransferase (ChAT). Although NSC-34 cell lines have been used to study the effect of various toxicological, neurotrophic and neuroprotective agents, the electrical activity of these cells has not been elucidated. In the current study, we have characterized the electrophysiological properties of NSC-34 cell lines using Micro-Electrode Array (MEA) as a tool. Based on the spike waveform, firing frequency, auto- and cross-correlogram analysis, we demonstrate that NSC-34 cell culture has >2 distinct types of neuronal population: principal excitatory neurons, putative interneurons and unclassified neurons. The presence of interneurons in the NSC-34 culture was characterized by increased expression of GAD-67 markers. Thus, finding an understanding of the electrophysiological properties of different population of neurons in NSC-34 cell line, will have multiple applications in the treatment of neurological disorders.

  3. Effects of Morphology Constraint on Electrophysiological Properties of Cortical Neurons.

    PubMed

    Zhu, Geng; Du, Liping; Jin, Lei; Offenhäusser, Andreas

    2016-04-07

    There is growing interest in engineering nerve cells in vitro to control architecture and connectivity of cultured neuronal networks or to build neuronal networks with predictable computational function. Pattern technologies, such as micro-contact printing, have been developed to design ordered neuronal networks. However, electrophysiological characteristics of the single patterned neuron haven't been reported. Here, micro-contact printing, using polyolefine polymer (POP) stamps with high resolution, was employed to grow cortical neurons in a designed structure. The results demonstrated that the morphology of patterned neurons was well constrained, and the number of dendrites was decreased to be about 2. Our electrophysiological results showed that alterations of dendritic morphology affected firing patterns of neurons and neural excitability. When stimulated by current, though both patterned and un-patterned neurons presented regular spiking, the dynamics and strength of the response were different. The un-patterned neurons exhibited a monotonically increasing firing frequency in response to injected current, while the patterned neurons first exhibited frequency increase and then a slow decrease. Our findings indicate that the decrease in dendritic complexity of cortical neurons will influence their electrophysiological characteristics and alter their information processing activity, which could be considered when designing neuronal circuitries.

  4. Clinical and electrophysiological characteristics of neuropathy associated with Tangier disease.

    PubMed

    Zyss, Julie; Béhin, Anthony; Couvert, Philippe; Bouhour, Françoise; Sassolas, Agnès; Kolev, Ivan; Denys, Violaine; Vial, Christophe; Lacour, A; Carrié, Alain; Stojkovic, Tanya

    2012-06-01

    Tangier disease (TD) (OMIM#205400) is a rare autosomal recessive disorder resulting from mutations in the ABCA1 gene, leading to decreased levels of plasma high-density lipoproteins (HDL). Peripheral neuropathy is a common finding in this disease, and may present as relapsing/remitting mono/polyneuropathies or as syringomyelia-like neuropathy. We retrospectively analyzed four patients, and report here their clinical, biological, electrophysiological, imaging, and genetic findings. Three patients had a typical pseudosyringomyelic neuropathy including facial diplegia, but asymmetrical onset was observed in one patient who had first been misdiagnosed with Lewis-Sumner syndrome. Electrophysiological pattern was heterogeneous, showing both signs of demyelination and axonal degeneration. Truncating mutations of the ABCA1 gene, including two previously undescribed mutations, were constantly found. Atypical symptom onset and demyelinating features on electrophysiological examination can be misleading in case of pseudosyringomyelic neuropathy. These reports illustrate two different neurological phenotypes in TD, namely the pseudosyringomyelic type and the Lewis-Sumner-like type, and advocate for a systematic assessment of lipid profile including HDL cholesterol in demyelinating neuropathies.

  5. Exploring the unknown: electrophysiological and behavioural measures of visuospatial learning.

    PubMed

    Quinlivan, Brendan; Butler, John S; Ridwan, Abdur Raquib; Beiser, Ines; Williams, Laura; McGovern, Eavan; O'Riordan, Sean; Hutchinson, Michael; Reilly, Richard B

    2016-05-01

    Visuospatial memory describes our ability to temporarily store and manipulate visual and spatial information and is employed for a wide variety of complex cognitive tasks. Here, a visuospatial learning task requiring fine motor control is employed to investigate visuospatial learning in a group of typically developing adults. Electrophysiological and behavioural data are collected during a target location task under two experimental conditions: Target Learning and Target Cued. Movement times (MTs) are employed as a behavioural metric of performance, while dynamic P3b amplitudes and power in the alpha band (approximately 10 Hz) are explored as electrophysiological metrics during visuospatial learning. Results demonstrate that task performance, as measured by MT, is highly correlated with P3b amplitude and alpha power at a consecutive trial level (trials 1-30). The current set of results, in conjunction with the existing literature, suggests that changes in P3b amplitude and alpha power could correspond to different aspects of the learning process. Here it is hypothesized that changes in P3b correspond to a diminishing inter-stimulus interval and reduced stimulus relevance, while the corresponding changes in alpha power represent an automation of response as habituation occurs in participants. The novel analysis presented in the current study demonstrates how gradual electrophysiological changes can be tracked during the visuospatial learning process under the current paradigm.

  6. Awareness during drowsiness: dynamics and electrophysiological correlates

    NASA Technical Reports Server (NTRS)

    Makeig, S.; Jung, T. P.; Sejnowski, T. J.

    2000-01-01

    During drowsy periods, performance on tasks requiring continuous attention becomes intermittent. Previously, we have reported that during drowsy periods of intermittent performance, 7 of 10 participants performing an auditory detection task exhibited episodes of non-responding lasting about 18 s (Makeig & Jung, 1996). Further, the time patterns of these episodes were repeated precisely in subsequent sessions. The 18-s cycles were accompanied by counterbalanced power changes within two frequency bands in the vertex EEG (near 4 Hz and circa 40 Hz). In the present experiment, performance patterns and concurrent EEG spectra were examined in four participants performing a continuous visuomotor compensatory tracking task in 15-20 minute bouts during a 42-hour sleep deprivation study. During periods of good performance, participants made compensatory trackball movements about twice per second, attempting to keep a target disk near a central ring. Autocorrelations of time series representing the distance of the target disk from the ring centre showed that during periods of poor performance marked near-18-s cycles in performance again appeared. There were phases of poor or absent performance accompanied by an increase in EEG power that was largest at 3-4 Hz. These studies show that in drowsy humans, opening and closing of the gates of behavioural awareness is marked not by the appearance of (12-14 Hz) sleep spindles, but by prominent EEG amplitude changes in the low theta band. Further, both EEG and behavioural changes during drowsiness often exhibit stereotyped 18-s cycles.

  7. A 3-year experience with necrotizing fasciitis: favorable outcomes despite operative delays in a busy acute care hospital.

    PubMed

    Pakula, Andrea M; Kapadia, Ravi; Freeman, Brandon; Skinner, Ruby A

    2012-10-01

    Necrotizing fasciitis is a rare severe soft tissue infection that has historically been associated with high mortality. We sought to evaluate our experience with necrotizing fasciitis focusing on outcomes based on timing of operative intervention. Our study hypothesis was that delays in surgical management would negatively impact outcomes. Fifty-four patients were identified for a retrospective chart review from January 2008 to January 2011. Data analysis included demographics, admission laboratory values, imaging results, examination findings, timing and nature of operations, length of stay (LOS), and outcomes. Surgical intervention in 12 hours or more was considered a delay in care. Our study cohort was high risk based on a high prevalence of intravenous drug abuse, diabetes mellitus, hypertension, and end-stage liver disease. The average time to surgical intervention was 18±25 hours and the overall mortality rate was 16 per cent. A delay to surgery did not impact mortality or the number of débridements and LOS. Mortality was high, 45 per cent, in patients requiring amputation. We observed a high-risk population managed with aggressive surgical care for necrotizing fasciitis. Our mortality was low compared with historical data and surgical delays did not impact outcomes. Those patients requiring amputation had worse outcomes.

  8. Prescriber preferences for behavioural economics interventions to improve treatment of acute respiratory infections: a discrete choice experiment

    PubMed Central

    Gong, Cynthia L; Hay, Joel W; Meeker, Daniella; Doctor, Jason N

    2016-01-01

    Objective To elicit prescribers' preferences for behavioural economics interventions designed to reduce inappropriate antibiotic prescribing, and compare these to actual behaviour. Design Discrete choice experiment (DCE). Setting 47 primary care centres in Boston and Los Angeles. Participants 234 primary care providers, with an average 20 years of practice. Main outcomes and measures Results of a behavioural economic intervention trial were compared to prescribers' stated preferences for the same interventions relative to monetary and time rewards for improved prescribing outcomes. In the randomised controlled trial (RCT) component, the 3 computerised prescription order entry-triggered interventions studied included: Suggested Alternatives (SA), an alert that populated non-antibiotic treatment options if an inappropriate antibiotic was prescribed; Accountable Justifications (JA), which prompted the prescriber to enter a justification for an inappropriately prescribed antibiotic that would then be documented in the patient's chart; and Peer Comparison (PC), an email periodically sent to each prescriber comparing his/her antibiotic prescribing rate with those who had the lowest rates of inappropriate antibiotic prescribing. A DCE study component was administered to determine whether prescribers felt SA, JA, PC, pay-for-performance or additional clinic time would most effectively reduce their inappropriate antibiotic prescribing. Willingness-to-pay (WTP) was calculated for each intervention. Results In the RCT, PC and JA were found to be the most effective interventions to reduce inappropriate antibiotic prescribing, whereas SA was not significantly different from controls. In the DCE however, regardless of treatment intervention received during the RCT, prescribers overwhelmingly preferred SA, followed by PC, then JA. WTP estimates indicated that each intervention would be significantly cheaper to implement than pay-for-performance incentives of $200/month

  9. Antibiotics for acute respiratory tract infections: a mixed-methods study of patient experiences of non-medical prescriber management

    PubMed Central

    Courtenay, Molly; Rowbotham, Samantha; Lim, Rosemary; Deslandes, Rhian; Hodson, Karen; MacLure, Katie; Peters, Sarah; Stewart, Derek

    2017-01-01

    Objective To (1) explore patients' expectations and experiences of nurse and pharmacist non-medical prescriber-led management of respiratory tract infections (RTIs), (2) examine whether patient expectations for antibiotics affect the likelihood of receiving them and (3) understand factors influencing patient satisfaction with RTI consultations. Design Mixed methods. Setting Primary care. Participants Questionnaires from 120 patients and follow-up interviews with 22 patients and 16 nurse and pharmacist non-medical prescribers (NMPs). Results Patients had multiple expectations of their consultation with 43% expecting to be prescribed an antibiotic. There was alignment between self-reported patient expectations and those perceived by NMPs. Patient expectations for non-antibiotic strategies, such as education to promote self-management, were associated with receipt of those strategies, whereas patient expectations for an antibiotic were not associated with receipt of these medications. ‘Patient-centred’ management strategies (including reassurance and providing information) were received by 86.7% of patients. Regardless of patients' expectations or the management strategy employed, high levels of satisfaction were reported for all aspects of the consultation. Taking concerns seriously, conducting a physical examination, communicating the treatment plan, explaining treatment decisions and lack of time restrictions were each reported to contribute to patient satisfaction. Conclusions NMPs demonstrate an understanding of patient expectations of RTI consultations and use a range of non-antibiotic management strategies, particularly those resembling a patient-centred approach. Overall, patients' expectations were met and prescribers were not unduly influenced by patient expectations for an antibiotic. Patients were satisfied with the consultation, indicating that strategies used by NMPs were acceptable. However, the lower levels of satisfaction among patients who

  10. Behavioral and Electrophysiological Responses Evoked by Chronic Infrared Neural Stimulation of the Cochlea

    PubMed Central

    Matic, Agnella Izzo; Robinson, Alan M.; Young, Hunter K.; Badofsky, Ben; Rajguru, Suhrud M.; Stock, Stuart; Richter, Claus-Peter

    2013-01-01

    Infrared neural stimulation (INS) has been proposed as a novel method for neural stimulation. In order for INS to translate to clinical use, which would involve the use of implanted devices over years or decades, the efficacy and safety of chronic INS needs to be determined. We examined a population of cats that were chronically implanted with an optical fiber to stimulate the cochlea with infrared radiation, the first known chronic application of INS. Through behavioral responses, the cats demonstrate that stimulation occurs and a perceptual event results. Long-term stimulation did not result in a change in the electrophysiological responses, either optically-evoked or acoustically-evoked. Spiral ganglion neuron counts and post implantation tissue growth, which was localized at the optical fiber, were similar in chronically stimulated and sham implanted cochleae. Results from chronic INS experiments in the cat cochlea support future work toward INS-based neuroprostheses for humans. PMID:23505466

  11. OpenElectrophy: An Electrophysiological Data- and Analysis-Sharing Framework

    PubMed Central

    Garcia, Samuel; Fourcaud-Trocmé, Nicolas

    2008-01-01

    Progress in experimental tools and design is allowing the acquisition of increasingly large datasets. Storage, manipulation and efficient analyses of such large amounts of data is now a primary issue. We present OpenElectrophy, an electrophysiological data- and analysis-sharing framework developed to fill this niche. It stores all experiment data and meta-data in a single central MySQL database, and provides a graphic user interface to visualize and explore the data, and a library of functions for user analysis scripting in Python. It implements multiple spike-sorting methods, and oscillation detection based on the ridge extraction methods due to Roux et al. (2007). OpenElectrophy is open source and is freely available for download at http://neuralensemble.org/trac/OpenElectrophy. PMID:19521545

  12. Electrophysiological observations in hippocampal slices from rats treated with the ketogenic diet.

    PubMed

    Stafstrom, C E; Wang, C; Jensen, F E

    1999-11-01

    The electrophysiological effects of the high-fat, low-carbohydrate ketogenic diet (KD) were assessed in normal and epileptic [kainic-acid(KA)-treated] adult rats using hippocampal slices. In the first set of experiments, normal rats were fed the KD or a standard control diet for 6-8 weeks (beginning on postnatal day 56, P56), after which they were sacrificed for hippocampal slices. All rats on the KD became ketotic. The baseline effects of the KD were determined by comparing extracellular measures of synaptic transmission and responses to evoked stimulation, and hippocampal excitability was tested in Mg(2+)-free medium. There were no differences in EPSP slope, input/output relationship, responses to evoked stimulation or Mg(2+)-free burst frequency between slices from control and KD-fed rats. In another set of experiments, rats were made epileptic by intraperitoneal injection of kainic acid (KA) on P54, which caused status epilepticus followed by the development of spontaneous recurrent seizures (SRS) over the next few weeks. Two days after KA-induced status, rats were divided into a control-fed group and a KD-fed group. Animals on the KD had significantly fewer SRS over the ensuing 8 weeks. In hippocampal slices from KA-treated, KD-fed rats, there were fewer evoked CA1 population spikes than from slices of control-fed rats. These results suggest that the KD does not alter baseline electrophysiological parameters in normal rats. In rats made chronically epileptic by administration of KA, KD treatment was associated with fewer spontaneous seizures and reduced CA1 excitability in vitro. Therefore, at least part of the KD mechanism of action may involve long-term changes in network excitability.

  13. What is involved in medicines management across care boundaries? A qualitative study of healthcare practitioners' experiences in the case of acute kidney injury

    PubMed Central

    Morris, Rebecca L; Blakeman, Tom; Ashcroft, Darren M

    2017-01-01

    Objectives To examine the role of individual and collective cognitive work in managing medicines for acute kidney injury (AKI), this being an example of a clinical scenario that crosses the boundaries of care organisations and specialties. Design Qualitative design, informed by a realist perspective and using semistructured interviews as the data source. The data were analysed using template analysis. Setting Primary, secondary and intermediate care in England. Participants 12 General practitioners, 10 community pharmacists, 7 hospital doctors and 7 hospital pharmacists, all with experience of involvement in preventing or treating AKI. Results We identified three main themes concerning participants' experiences of managing medicines in AKI. In the first theme, challenges arising from the clinical context, AKI is identified as a technically complex condition to identify and treat, often requiring judgements to be made about renal functioning against the context of the patient's general well-being. In the second theme, challenges arising from the organisational context, the crossing of professional and organisational boundaries is seen to introduce problems for the coordination of clinical activities, for example by disrupting information flows. In the third theme, meeting the challenges, participants identify ways in which they overcome the challenges they face in order to ensure effective medicines management, for example by adapting their work practices and tools. Conclusions These themes indicate the critical role of cognitive work on the part of healthcare practitioners, as individuals and as teams, in ensuring effective medicines management during AKI. Our findings suggest that the capabilities underlying this work, for example decision-making, communication and team coordination, should be the focus of training and work design interventions to improve medicines management for AKI or for other conditions. PMID:28100559

  14. Effects of Hydrazine on Electrophysiology, Behavior and Runway Performance in the Cat.

    DTIC Science & Technology

    HYDRAZINES, *ROCKET PROPELLANTS, ELECTROENCEPHALOGRAPHY, TOXICITY, BEHAVIOR, PERFORMANCE(HUMAN), CENTRAL NERVOUS SYSTEM, TOXIC TOLERANCES, PERMISSIBLE DOSAGE, BODY WEIGHT, ELECTROPHYSIOLOGY, BRAIN , CATS, EXPERIMENTAL DATA.

  15. Electrophysiological Properties of Subventricular Zone Cells in Adult Mouse Brain

    PubMed Central

    Lai, Bin; Mao, Xiao Ou; Xie, Lin; Chang, Su-Youne; Xiong, Zhi-Gang; Jin, Kunlin; Greenberg, David A.

    2010-01-01

    The subventricular zone (SVZ) is a principal site of adult neurogenesis and appears to participate in the brain’s response to injury. Thus, measures that enhance SVZ neurogenesis may have a role in treatment of neurological disease. To better characterize SVZ cells and identify potential targets for therapeutic intervention, we studied electrophysiological properties of SVZ cells in adult mouse brain slices using patch-clamp techniques. Electrophysiology was correlated with immunohistochemical phenotype by injecting cells with lucifer yellow and by studying transgenic mice carrying green fluorescent protein under control of the doublecortin (DCX) or glial fibrillary acidic protein (GFAP) promoter. We identified five types of cells in the adult mouse SVZ: type 1 cells, with 4-aminopyridine (4-AP)/tetraethylammonium (TEA)-sensitive and CdCl2-sensitive inward currents; type 2 cells, with Ca2+-sensitive K+ and both 4-AP/TEA-sensitive and -insensitive currents; type 3 cells, with 4-AP/TEA-sensitive and -insensitive and small Na+ currents; type 4 cells, with slowly activating, large linear outward current and sustained outward current without fast-inactivating component; and type 5 cells, with a large outward rectifying current with a fast inactivating component. Type 2 and 3 cells expressed DCX, types 4 and 5 cells expressed GFAP, and type 1 cells expressed neither. We propose that SVZ neurogenesis involves a progression of electrophysiological cell phenotypes from types 4 and 5 cells (astrocytes) to type 1 cells (neuronal progenitors) to types 2 and 3 cells (nascent neurons), and that drugs acting on. ion channels expressed during neurogenesis might promote therapeutic neurogenesis in the injured brain. PMID:20434436

  16. [Electrophysiological characteristics of asymptomatic Wolff-Parkinson-White syndromes].

    PubMed

    Brembilla-Perrot, B; Ghawi, R; Dechaux, J P

    1991-11-01

    The management of the Wolff-Parkinson-White syndrome (WPW) is controversial especially when the patient is asymptomatic. The aim of this study was to evaluate the electrophysiological characteristics of such patients. Thirty two asymptomatic subjects with overt WPW on the surface ECG aged 14 to 68 years (average 36 +/- 15 years) underwent endocavitary or oesophageal electrophysiological study with the following protocol: programmed atrial stimulation using 1 or 2 extrastimuli over 3 cycles to evaluate the induction of paroxysmal junctional tachycardia and atrial fibrillation; atrial pacing at increasing frequencies to assess the shortest cycle conducted by the bundle of Kent. This protocol was repeated during intravenous infusion of 20 to 30 mg of Isoproterenol. Four electrophysiological characteristics were identified: the incidence of induction of junctional tachycardia was very low (2 cases, 6%); the incidence of induction of atrial fibrillation or tachycardia was similar to that of symptomatic WPW (9 cases 30%); the incidence of rapid conduction via the bundle of Kent (cycle conducted by the Kent less than 250 ms under basal conditions less than 200 ms with Isoproterenol) was 19% (6 cases); the incidence of potentially serious forms of WPW with rapid conduction in the bundle of Kent and atrial vulnerability (induction of atrial fibrillation at a frequency less than the Wenckebach point by programmed atrial stimulation) was similar to that in symptomatic WPW, 3 cases (10%). In conclusion, the asymptomatic character of the WPW is very probably due to the absence of junctional tachycardias. Nevertheless, these patients are at risk of atrial fibrillation with an incidence of potentially serious forms of 10%.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Optic Nerve Dysfunction in Obstructive Sleep Apnea: An Electrophysiological Study

    PubMed Central

    Liguori, Claudio; Palmieri, Maria Giuseppina; Pierantozzi, Mariangela; Cesareo, Massimo; Romigi, Andrea; Izzi, Francesca; Marciani, Maria Grazia; Oliva, Corrado; Mercuri, Nicola Biagio; Placidi, Fabio

    2016-01-01

    Study Objectives: The aim of this study was to evaluate the integrity of the visual system in patients affected by obstructive sleep apnea (OSA) by means of electroretinogram (ERG) and visual evoked potential (VEP). Methods: We performed electrophysiological study of the visual system in a population of severe OSA (apnea-hypopnea events/time in bed ≥ 30/h) patients without medical comorbidities compared to a group of healthy controls similar for age, sex, and body mass index. Patients and controls did not have visual impairment or systemic disorders with known influence on the visual system. ERG and VEP were elicited by a reversal pattern generated on a television monitor at low (55') and high (15') spatial frequencies stimulation. Daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS) in both patients and controls. Results: In comparison with healthy controls (n = 27), patients with OSA (n = 27) showed a significant latency delay coupled with a significant amplitude reduction of P100 wave of VEP at all spatial frequencies in both eyes. No significant differences between groups were detected as concerning ERG components. No correlations were found between polygraphic parameters, ESS scores, or VEP and ERG components in OSA patients. Conclusions: This study documented that patients with OSA, without medical comorbidities, present VEP alteration as documented by lower amplitude and longer latency of the P100 component than healthy controls. These altered electrophysiological findings may be the expression of optic nerve dysfunction provoked by hypoxia, acidosis, hypercarbia and airway obstruction, frequently observed in patients with OSA. Hence, we hypothesize that OSA per se may impair optic nerve function. Citation: Liguori C, Palmieri MG, Pierantozzi M, Cesareo M, Romigi A, Izzi F, Marciani MG, Oliva C, Mercuri NB, Placidi F. Optic nerve dysfunction in obstructive sleep apnea: an electrophysiological study. SLEEP 2016;39(1):19–23. PMID

  18. Electrophysiology in the Developing World: Challenges and Opportunities.

    PubMed

    Bestawros, Michael

    2017-02-01

    As a subset of the growing epidemic of cardiovascular morbidity and mortality in low-income and middle-income countries (LMICs), the significant burdens of heart rhythm disorders also increase. Effective diagnostic and treatment modalities exist, but financial resources and expertise are limited. Cost-effective strategies exist to address most of these limitations, but many surmountable barriers need to be overcome to introduce and improve electrophysiologic care in LMICs. In this article, current and potential solutions are offered for the diagnostic and therapeutic challenges of managing bradyarrhythmias and tachyarrhythmias.

  19. Electrophysiological studies of malaria parasite-infected erythrocytes: Current status

    PubMed Central

    Staines, Henry M.; Alkhalil, Abdulnaser; Allen, Richard J.; De Jonge, Hugo R.; Derbyshire, Elvira; Egée, Stéphane; Ginsburg, Hagai; Hill, David A.; Huber, Stephan M.; Kirk, Kiaran; Lang, Florian; Lisk, Godfrey; Oteng, Eugene; Pillai, Ajay D.; Rayavara, Kempaiah; Rouhani, Sherin; Saliba, Kevin J.; Shen, Crystal; Solomon, Tsione; Thomas, Serge L. Y.; Verloo, Patrick; Desai, Sanjay A.

    2009-01-01

    The altered permeability characteristics of erythrocytes infected with malaria parasites have been a source of interest for over 30 years. Recent electrophysiological studies have provided strong evidence that these changes reflect transmembrane transport through ion channels in the host erythrocyte plasma membrane. However, conflicting results and differing interpretations of the data have led to confusion in this field. In an effort to unravel these issues, the groups involved recently came together for a week of discussion and experimentation. In this article, the various models for altered transport are reviewed, together with the areas of consensus in the field and those that require a better understanding. PMID:17292372

  20. Hourglass-shaped aperture for cellular electrophysiological study

    NASA Astrophysics Data System (ADS)

    Chen, Chang-Yu; Liu, Kuan-Ting; Jong, De-Shien; Wo, Andrew M.

    2007-09-01

    This work presents a simple process of reflow of melted glass by CO2 laser to form an hourglass-shaped aperture for cellular electrophysiological study. The fabricated aperture proves to be smooth, circular, debris-free, and freshly activated. Two-phase flow simulation illuminates details of the reflow process. The resulting seal resistance quality is well suited to measure ion-channel activities; a seal resistance of 1.9GΩ for PC-12 cell and a typical resistance of 200MΩ for Chinese hamster ovary cells were achieved. This approach can be integrated with microfluidics in a single cell patch or array configuration.

  1. National Registry on Cardiac Electrophysiology 2007 and 2008.

    PubMed

    da Silva, Manuel Nogueira; Bonhorst, Daniel; de Sousa, João

    2009-11-01

    Clinical electrophysiology remains one of the most dynamic areas of cardiology, with continuing developments in equipping centers with more modern mapping and navigation systems. This has enabled an increase in the number and variety of interventions, resulting in significant improvements in results of therapeutic ablation of arrhythmias and prevention of sudden cardiac death. In this phase of transition towards implementation of a computerized national registry with nationwide data transmitted via the internet, publication of the registry in its previous form, although requiring more work, still seems justified, in order to appraise and disseminate qualitative and quantitative developments in this activity and enable comparisons with what is being done internationally, assess the centers' training capacity and inform national and European health authorities of the activities and real needs in this sector. The authors analyze the number and type of procedures performed during 2007 and 2008 based on a survey sent to centers performing diagnostic and interventional electrophysiology (16 centers in 2007 and 2008) and/or implanting cardioverter-defibrillators (ICDs) (19 centers in 2007 and 21 in 2008). Compared to 2006, one more center began interventional electrophysiology in 2007 and two centers began implanting ICDs in 2008. In the years under review, 2060 electrophysiological studies were performed in 2007 and 2007 were performed in 2008, of which 74 and 79.5% respectively were followed by therapeutic ablation, making totals of 1523 and 1596 ablations (increases of 10.7 and 4.6% from previous years). Atrioventricular nodal reentrant tachycardia was the main indication for ablation (28.4 and 28.7%), followed by accessory pathways (26.8 and 25.4%), atrial flutter (20.8 and 19.7%), atrial fibrillation (13.9 and 14.6%), ventricular tachycardia (4.7 and 5.1%), atrial tachycardia (2.8 and 2.6%) and atrioventricular junction ablation (2.7 and 3.9%). Regarding ICDs, a

  2. [Electrophysiological research on pain and itching in the clinic].

    PubMed

    Dallakian, I G; Zhukova, I K; Filina, T F; Samsonov, V A

    1988-01-01

    To study the central mechanisms of pain and itching, the authors performed electroencephalographic (EEG) examination in acupuncture-treated patients with diffuse neurodermatitis (n = 43) and trigeminal neuralgia (n = 25). The most characteristic EEG finding was increased synchronization of the cortical rhythm. The revealed EEG features point to the functional involvement of the thalamocortical system in the development of pain and itching. Changes of clinical and electrophysiological parameters in the course of acupuncture treatment is an additional evidence of the morphofunctional unity of the development of pain and itching.

  3. Clinical and electrophysiological observations in patients with low pressure retinopathy.

    PubMed Central

    Russell, R W; Ikeda, H

    1986-01-01

    The clinical, angiographic, and electrophysiological features of seven patients with transient visual loss and low-pressure retinopathy are presented. Six of the patients also had symptoms of cerebral ischaemia. The commonest provoking feature was bright light. Angiography showed multiple extracranial occlusions involving both internal and external carotid arteries in addition to occlusion or stenosis on the contralateral side. Electroretinography showed delay in the recovery of the b wave in the affected eye after exposure to bright light. This appears to be a valuable test for the detection of minor degrees of ischaemic damage to the retina caused by insufficiency of the retinal and choroidal circulation. Images PMID:3756120

  4. [A new method in fetal heart electrophysiology - fetal magnetocardiography].

    PubMed

    Wacker-Gussmann, A; Lim, M; Henes, J; Preissl, H; Abele, H; Kiefer, I

    2011-06-01

    Fetal magnetocardiography (fMCG) is used as a non-invasive method for registering the electrophysiological fetal heart activity. Superconducting quantum interference device-based magnetometers are currently used to make fMCG recordings. In contrast to fetal ECG, this method is independent of signal loss due to isolating factors such as, especially, the vernix caesaroa between the 27th and 34th weeks of gestation. We report about a term newborn with a third degree AV block, examined by this method.

  5. Molecular and Electrophysiological Mechanisms Underlying Cardiac Arrhythmogenesis in Diabetes Mellitus

    PubMed Central

    Tse, Vivian; Yeo, Jie Ming

    2016-01-01

    Diabetes is a common endocrine disorder with an ever increasing prevalence globally, placing significant burdens on our healthcare systems. It is associated with significant cardiovascular morbidities. One of the mechanisms by which it causes death is increasing the risk of cardiac arrhythmias. The aim of this article is to review the cardiac (ion channel abnormalities, electrophysiological and structural remodelling) and extracardiac factors (neural pathway remodelling) responsible for cardiac arrhythmogenesis in diabetes. It is concluded by an outline of molecular targets for future antiarrhythmic therapy for the diabetic population. PMID:27642609

  6. [Photophobic response in Stentor coeruleus--electrophysiologic investigations].

    PubMed

    Walerczyk, M; Fabczak, H; Fabczak, S

    2000-01-01

    It is widely known that the phototransduction process in vertebrate photoreceptor cells are mediated by cGMP-gated ionic channels. The recent electrophysiological study showed that the cGMP-gated channels are also present in light sensitive protozoan ciliate Stentor coeruleus. These channels might play a key role in phototransduction process which leads to the photophobic behavior in the ciliate. The basic biophysical and pharmaceutical properties of cGMP-gated channels in Stentor indicate high similarity to those in vertebrate photoreceptor cells.

  7. Computer simulation of fibrillation threshold measurements and electrophysiologic testing procedures

    NASA Technical Reports Server (NTRS)

    Grumbach, M. P.; Saxberg, B. E.; Cohen, R. J.

    1987-01-01

    A finite element model of cardiac conduction was used to simulate two experimental protocols: 1) fibrillation threshold measurements and 2) clinical electrophysiologic (EP) testing procedures. The model consisted of a cylindrical lattice whose properties were determined by four parameters: element length, conduction velocity, mean refractory period, and standard deviation of refractory periods. Different stimulation patterns were applied to the lattice under a given set of lattice parameter values and the response of the model was observed through a simulated electrocardiogram. The studies confirm that the model can account for observations made in experimental fibrillation threshold measurements and in clinical EP testing protocols.

  8. High-frequency ultrasound as an adjunct to neural electrophysiology: Evaluation and prognosis of Bell's palsy.

    PubMed

    Li, Shuo; Guo, Rui-Jun; Liang, Xiao-Ning; Wu, Yue; Cao, Wen; Zhang, Zhen-Ping; Zhao, Wei; Liang, Hai-Dong

    2016-01-01

    Bell's palsy is a form of temporary facial nerve paralysis that occurs primarily in young adults. Previously, various methods were used to assess outcomes in facial nerve disease. The aim of the present study was to characterize the main branches of the normal and abnormal facial nerve using high-frequency ultrasonography (HFUS). A total of 104 healthy volunteers, 40 patients with acute onset of Bell's palsy and 30 patients who underwent 3-month routine therapy for Bell's palsy disease were included in the study. The healthy volunteers and patients were selected for HFUS examination and VII nerve conduction. The results showed significant differences in nerve diameter, echogenicity, delitescence and amplitude in different groups. Statistically significant correlations were identified for severity grading in one of the experimental groups during HFUS examinations. In conclusion, HFUS as a complementary technique paired with neural electrophysiology may establish the normal values of facial nerve. Additionally, HFUS was beneficial in the process of evaluation and prognosis of Bell's palsy disease.

  9. High-frequency ultrasound as an adjunct to neural electrophysiology: Evaluation and prognosis of Bell's palsy

    PubMed Central

    LI, SHUO; GUO, RUI-JUN; LIANG, XIAO-NING; WU, YUE; CAO, WEN; ZHANG, ZHEN-PING; ZHAO, WEI; LIANG, HAI-DONG

    2016-01-01

    Bell's palsy is a form of temporary facial nerve paralysis that occurs primarily in young adults. Previously, various methods were used to assess outcomes in facial nerve disease. The aim of the present study was to characterize the main branches of the normal and abnormal facial nerve using high-frequency ultrasonography (HFUS). A total of 104 healthy volunteers, 40 patients with acute onset of Bell's palsy and 30 patients who underwent 3-month routine therapy for Bell's palsy disease were included in the study. The healthy volunteers and patients were selected for HFUS examination and VII nerve conduction. The results showed significant differences in nerve diameter, echogenicity, delitescence and amplitude in different groups. Statistically significant correlations were identified for severity grading in one of the experimental groups during HFUS examinations. In conclusion, HFUS as a complementary technique paired with neural electrophysiology may establish the normal values of facial nerve. Additionally, HFUS was beneficial in the process of evaluation and prognosis of Bell's palsy disease. PMID:26889221

  10. Integration of electrophysiological recordings with single-cell RNA-seq data identifies neuronal subtypes.

    PubMed

    Fuzik, János; Zeisel, Amit; Máté, Zoltán; Calvigioni, Daniela; Yanagawa, Yuchio; Szabó, Gábor; Linnarsson, Sten; Harkany, Tibor

    2016-02-01

    Traditionally, neuroscientists have defined the identity of neurons by the cells' location, morphology, connectivity and excitability. However, the direct relationship between these parameters and the molecular phenotypes has remained largely unexplored. Here, we present a method for obtaining full transcriptome data from single neocortical pyramidal cells and interneurons after whole-cell patch-clamp recordings in mouse brain slices. In our approach, termed Patch-seq, a patch-clamp stimulus protocol is followed by the aspiration of the entire somatic compartment into the recording pipette, reverse transcription of RNA including addition of unique molecular identifiers, cDNA amplification, Illumina library preparation and sequencing. We show that Patch-seq reveals a close link between electrophysiological characteristics, responses to acute chemical challenges and RNA expression of neurotransmitter receptors and channels. Moreover, it distinguishes neuronal subpopulations that correspond to both well-established and, to our knowledge, hitherto undescribed neuronal subtypes. Our findings demonstrate the ability of Patch-seq to precisely map neuronal subtypes and predict their network contributions in the brain.

  11. Electrophysiological characterization of Grueneberg ganglion olfactory neurons: spontaneous firing, sodium conductance, and hyperpolarization-activated currents.

    PubMed

    Liu, Cambrian Y; Xiao, Cheng; Fraser, Scott E; Lester, Henry A; Koos, David S

    2012-09-01

    Mammals rely on their acute olfactory sense for their survival. The most anterior olfactory subsystem in the nose, the Grueneberg ganglion (GG), plays a role in detecting alarm pheromone, cold, and urinary compounds. GG neurons respond homogeneously to these stimuli with increases in intracellular [Ca(2+)] or transcription of immediate-early genes. In this electrophysiological study, we used patch-clamp techniques to characterize the membrane properties of GG neurons. Our results offer evidence of functional heterogeneity in the GG. GG neurons fire spontaneously and independently in several stable patterns, including phasic and repetitive single-spike modes of discharge. Whole cell recordings demonstrated two distinct voltage-gated fast-inactivating Na(+) currents with different steady-state voltage dependencies and different sensitivities to tetrodotoxin. Hodgkin-Huxley simulations showed that these Na(+) currents confer dual mechanisms of action potential generation and contribute to different firing patterns. Additionally, GG neurons exhibited hyperpolarization-activated inward currents that modulated spontaneous firing in vitro. Thus, in GG neurons, the heterogeneity of firing patterns is linked to the unusual repertoire of ionic currents. The membrane properties described here will aid the interpretation of chemosensory function in the GG.

  12. Incubator-independent cell-culture perfusion platform for continuous long-term microelectrode array electrophysiology and time-lapse imaging

    PubMed Central

    Saalfrank, Dirk; Konduri, Anil Krishna; Latifi, Shahrzad; Habibey, Rouhollah; Golabchi, Asiyeh; Martiniuc, Aurel Vasile; Knoll, Alois; Ingebrandt, Sven; Blau, Axel

    2015-01-01

    Most in vitro electrophysiology studies extract information and draw conclusions from representative, temporally limited snapshot experiments. This approach bears the risk of missing decisive moments that may make a difference in our understanding of physiological events. This feasibility study presents a simple benchtop cell-culture perfusion system adapted to commercial microelectrode arrays (MEAs), multichannel electrophysiology equipment and common inverted microscopy stages for simultaneous and uninterrupted extracellular electrophysiology and time-lapse imaging at ambient CO2 levels. The concept relies on a transparent, replica-casted polydimethylsiloxane perfusion cap, gravity- or syringe-pump-driven perfusion and preconditioning of pH-buffered serum-free cell-culture medium to ambient CO2 levels at physiological temperatures. The low-cost microfluidic in vitro enabling platform, which allows us to image cultures immediately after cell plating, is easy to reproduce and is adaptable to the geometries of different cell-culture containers. It permits the continuous and simultaneous multimodal long-term acquisition or manipulation of optical and electrophysiological parameter sets, thereby considerably widening the range of experimental possibilities. Two exemplary proof-of-concept long-term MEA studies on hippocampal networks illustrate system performance. Continuous extracellular recordings over a period of up to 70 days revealed details on both sudden and gradual neural activity changes in maturing cell ensembles with large intra-day fluctuations. Correlated time-lapse imaging unveiled rather static macroscopic network architectures with previously unreported local morphological oscillations on the timescale of minutes. PMID:26543581

  13. Acute Bronchitis

    MedlinePlus

    ... can also cause acute bronchitis. To diagnose acute bronchitis, your health care provider will ask about your symptoms and listen to your breathing. You may also have other tests. Treatments include rest, fluids, and aspirin (for adults) or ...

  14. No Evidence for Sex Differences in the Electrophysiological Properties and Excitatory Synaptic Input onto Nucleus Accumbens Shell Medium Spiny Neurons123

    PubMed Central

    Will, Tyler; Hauser, Caitlin A.; Cao, Jinyan

    2016-01-01

    Sex differences exist in how the brain regulates motivated behavior and reward, both in normal and pathological contexts. Investigations into the underlying neural mechanisms have targeted the striatal brain regions, including the dorsal striatum and nucleus accumbens core and shell. These investigations yield accumulating evidence of sexually different electrophysiological properties, excitatory synaptic input, and sensitivity to neuromodulator/hormone action in select striatal regions both before and after puberty. It is unknown whether the electrical properties of neurons in the nucleus accumbens shell differ by sex, and whether sex differences in excitatory synaptic input are present before puberty. To test the hypothesis that these properties differ by sex, we performed whole-cell patch-clamp recordings on male and female medium spiny neurons (MSNs) in acute brain slices obtained from prepubertal rat nucleus accumbens shell. We analyzed passive and active electrophysiological properties, and miniature EPSCs (mEPSCs). No sex differences were detected; this includes those properties, such as intrinsic excitability, action potential afterhyperpolarization, threshold, and mEPSC frequency, that have been found to differ by sex in other striatal regions and/or developmental periods. These findings indicate that, unlike other striatal brain regions, the electrophysiological properties of nucleus accumbens shell MSNs do not differ by sex. Overall, it appears that sex differences in striatal function, including motivated behavior and reward, are likely mediated by other factors and striatal regions. PMID:27022621

  15. Cardiotoxic Electrophysiological Effects of the Herbicide Roundup(®) in Rat and Rabbit Ventricular Myocardium In Vitro.

    PubMed

    Gress, Steeve; Lemoine, Sandrine; Puddu, Paolo-Emilio; Séralini, Gilles-Eric; Rouet, René

    2015-10-01

    Roundup (R), a glyphosate (G)-based herbicide (GBH), containing unknown adjuvants is widely dispersed around the world. Used principally by farmers, intoxications have increasingly been reported. We have studied R effects (containing 36 % of G) on right ventricular tissues (male Sprague-Dawley rats, up to 20,000 ppm and female New Zealand rabbits, at 25 and 50 ppm), to investigate R cardiac electrophysiological actions in vitro. We tested the reduced Ca(++) intracellular uptake mechanism as one potential cause of the electrical abnormalities after GBH superfusion, using the Na(+)/K(+)-ATPase inhibitor ouabain or the 1,4-dihydropyridine L-type calcium channel agonist BAY K 8644 which increases I Ca. R concentrations were selected based on human blood ranges found after acute intoxication. The study showed dose-dependent V max, APD50 and APD90 variations during 45 min of R superfusion. At the highest concentrations tested, there was a high incidence of conduction blocks, and 30-min washout with normal Tyrode solution did not restore excitability. We also observed an increased incidence of arrhythmias at different doses of R. Ouabain and BAY K 8644 prevented V max decrease, APD90 increase and the cardiac inexcitability induced by R 50 ppm. Glyphosate alone (18 and 180 ppm) had no significant electrophysiological effects. Thus, the action potential prolonging effect of R pointing to I Ca interference might explain both conduction blocks and proarrhythmia in vitro. These mechanisms may well be causative of QT prolongation, atrioventricular conduction blocks and arrhythmias in man after GBH acute intoxications as reported in retrospective hospital records.

  16. How do astrocytes shape synaptic transmission? Insights from electrophysiology

    PubMed Central

    Dallérac, Glenn; Chever, Oana; Rouach, Nathalie

    2013-01-01

    A major breakthrough in neuroscience has been the realization in the last decades that the dogmatic view of astroglial cells as being merely fostering and buffering elements of the nervous system is simplistic. A wealth of investigations now shows that astrocytes actually participate in the control of synaptic transmission in an active manner. This was first hinted by the intimate contacts glial processes make with neurons, particularly at the synaptic level, and evidenced using electrophysiological and calcium imaging techniques. Calcium imaging has provided critical evidence demonstrating that astrocytic regulation of synaptic efficacy is not a passive phenomenon. However, given that cellular activation is not only represented by calcium signaling, it is also crucial to assess concomitant mechanisms. We and others have used electrophysiological techniques to simultaneously record neuronal and astrocytic activity, thus enabling the study of multiple ionic currents and in depth investigation of neuro-glial dialogues. In the current review, we focus on the input such approach has provided in the understanding of astrocyte-neuron interactions underlying control of synaptic efficacy. PMID:24101894

  17. Individual differences in reinforcement learning: behavioral, electrophysiological, and neuroimaging correlates.

    PubMed

    Santesso, Diane L; Dillon, Daniel G; Birk, Jeffrey L; Holmes, Avram J; Goetz, Elena; Bogdan, Ryan; Pizzagalli, Diego A

    2008-08-15

    During reinforcement learning, phasic modulations of activity in midbrain dopamine neurons are conveyed to the dorsal anterior cingulate cortex (dACC) and basal ganglia (BG) and serve to guide adaptive responding. While the animal literature supports a role for the dACC in integrating reward history over time, most human electrophysiological studies of dACC function have focused on responses to single positive and negative outcomes. The present electrophysiological study investigated the role of the dACC in probabilistic reward learning in healthy subjects using a task that required integration of reinforcement history over time. We recorded the feedback-related negativity (FRN) to reward feedback in subjects who developed a response bias toward a more frequently rewarded ("rich") stimulus ("learners") versus subjects who did not ("non-learners"). Compared to non-learners, learners showed more positive (i.e., smaller) FRNs and greater dACC activation upon receiving reward for correct identification of the rich stimulus. In addition, dACC activation and a bias to select the rich stimulus were positively correlated. The same participants also completed a monetary incentive delay (MID) task administered during functional magnetic resonance imaging. Compared to non-learners, learners displayed stronger BG responses to reward in the MID task. These findings raise the possibility that learners in the probabilistic reinforcement task were characterized by stronger dACC and BG responses to rewarding outcomes. Furthermore, these results highlight the importance of the dACC to probabilistic reward learning in humans.

  18. [Electrophysiology and calcium signalling in human bronchial smooth muscle].

    PubMed

    Marthan, R; Hyvelin, J M; Roux, E; Savineau, J P

    1999-01-01

    Recently, cells isolated from airways have been used to characterize precisely the electrophysiological properties of this smooth muscle and to describe the changes in cytosolic calcium concentration ([Ca2+]i) occurring upon agonist stimulation. Although most studies have produced consistent results in terms of types of ion channel and pathways of calcium signalling implicated in the mechanical activity of airways, there are differences according to (i) the site along the bronchial tree (trachea vs. bronchi); (ii) the proliferating status of the cells (freshly isolated vs. cultured) and (iii) the species (human vs. animals). With regard to the electrophysiological properties of airway smooth muscle, the contribution to [Ca2+]i rise of Ca2+ influx through L-type voltage-dependent calcium channels depends on the balance between depolarization related to non-specific cation channel and/or chloride channel activation and hyperpolarization related to activation of a variety of potassium channels. Most of the above-mentioned channels appear to be controlled, directly or indirectly, by agonists in human bronchial smooth muscle. With regard to calcium signalling, the pattern of agonist-induced [Ca2+]i responses, the so-called [Ca2+]i oscillations, has been observed recently in freshly isolated airway smooth muscle cells. The role and the calcium sources involved in these oscillations in human bronchial smooth muscle are currently being investigated.

  19. Electrophysiological heterogeneity and stability of reentry in simulated cardiac tissue.

    PubMed

    Xie, F; Qu, Z; Garfinkel, A; Weiss, J N

    2001-02-01

    Generation of wave break is a characteristic feature of cardiac fibrillation. In this study, we investigated how dynamic factors and fixed electrophysiological heterogeneity interact to promote wave break in simulated two-dimensional cardiac tissue, by using the Luo-Rudy (LR1) ventricular action potential model. The degree of dynamic instability of the action potential model was controlled by varying the maximal amplitude of the slow inward Ca(2+) current to produce spiral waves in homogeneous tissue that were either nearly stable, meandering, hypermeandering, or in breakup regimes. Fixed electrophysiological heterogeneity was modeled by randomly varying action potential duration over different spatial scales to create dispersion of refractoriness. We found that the degree of dispersion of refractoriness required to induce wave break decreased markedly as dynamic instability of the cardiac model increased. These findings suggest that reducing the dynamic instability of cardiac cells by interventions, such as decreasing the steepness of action potential duration restitution, may still have merit as an antifibrillatory strategy.

  20. Distribution of electrophysiological abnormality in Lambert-Eaton myasthenic syndrome

    PubMed Central

    Maddison, P.; Newsom-Davis, J.; Mills, K.

    1998-01-01

    OBJECTIVE—To assess the distribution of electrophysiological abnormality in Lambert-Eaton myasthenic syndrome (LEMS) to identify the most sensitive muscle to use in routine examination.
METHODS—Surface recorded compound muscle action potential (CMAP) amplitudes were made from abductor digiti minimi, abductor pollicis brevis, anconeus, biceps brachii, and trapezius in 10 patients with LEMS. The effect of 3,4-diaminopyridine (3,4-DAP) was recorded in each muscle in nine patients. CMAP amplitudes were measured at rest and immediately after 10 seconds maximal voluntary contraction in each muscle. Values were compared with results obtained from 12 healthy controls.
RESULTS—Resting CMAP amplitudes were reduced in at least one muscle in all patients compared with controls, most markedly in abductor digiti minimi and anconeus. The administration of 3,4-DAP resulted in significantly improved resting CMAP amplitudes in trapezius only. After maximal voluntary muscle contraction, characteristic increments in CMAP amplitude of over 100% above resting values were seen in abductor digiti minimi and abductor pollicis brevis in seven patients, anconeus and biceps brachii in five patients. No patient had this level of increment in trapezius.
CONCLUSION—Despite predominantly proximal limb weakness seen clinically in patients with LEMS, the most sensitive muscles for detecting characteristic electrophysiological abnormalities of low resting CMAP amplitude and increment of over 100% after 10 seconds maximal voluntary contraction are abductor digiti minimi, abductor pollicis brevis, and anconeus.

 PMID:9703174

  1. Simultaneous electrophysiological recording and calcium imaging of suprachiasmatic nucleus neurons.

    PubMed

    Irwin, Robert P; Allen, Charles N

    2013-12-08

    Simultaneous electrophysiological and fluorescent imaging recording methods were used to study the role of changes of membrane potential or current in regulating the intracellular calcium concentration. Changing environmental conditions, such as the light-dark cycle, can modify neuronal and neural network activity and the expression of a family of circadian clock genes within the suprachiasmatic nucleus (SCN), the location of the master circadian clock in the mammalian brain. Excitatory synaptic transmission leads to an increase in the postsynaptic Ca(2+) concentration that is believed to activate the signaling pathways that shifts the rhythmic expression of circadian clock genes. Hypothalamic slices containing the SCN were patch clamped using microelectrodes filled with an internal solution containing the calcium indicator bis-fura-2. After a seal was formed between the microelectrode and the SCN neuronal membrane, the membrane was ruptured using gentle suction and the calcium probe diffused into the neuron filling both the soma and dendrites. Quantitative ratiometric measurements of the intracellular calcium concentration were recorded simultaneously with membrane potential or current. Using these methods it is possible to study the role of changes of the intracellular calcium concentration produced by synaptic activity and action potential firing of individual neurons. In this presentation we demonstrate the methods to simultaneously record electrophysiological activity along with intracellular calcium from individual SCN neurons maintained in brain slices.

  2. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study.

    PubMed

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18-25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function.

  3. Analysis of electrophysiological properties and responses of neutrophils

    PubMed Central

    Morgan, Deri; DeCoursey, Thomas E.

    2014-01-01

    Summary The past decade has seen increasing use of the patch clamp technique on neutrophils and eosinophils. The main goal of these electrophysiological studies has been to elucidate the mechanisms underlying the phagocyte respiratory burst. NADPH oxidase activity, which defines the respiratory burst in granulocytes, is electrogenic because electrons from NADPH are transported across the cell membrane, where they reduce oxygen to form superoxide anion (O2−). This passage of electrons comprises an electrical current that would rapidly depolarize the membrane if the charge movement were not balanced by proton efflux. The patch clamp technique enables simultaneous recording of NADPH oxidase-generated electron current and H+ flux through the closely related H+ channel. Increasing evidence suggests that other ion channels may play crucial roles in degranulation, phagocytosis, and chemotaxis, highlighting the importance of electrophysiological studies to advance knowledge of granulocyte function. Several configurations of the patch clamp technique exist. Each has advantages and limitations that are discussed here. Meaningful measurements of ion channels cannot be achieved without an understanding of their fundamental properties. We describe the types of measurements that are necessary to characterize a particular ion channel. PMID:24504950

  4. Zebrafish heart as a model for human cardiac electrophysiology

    PubMed Central

    Vornanen, Matti; Hassinen, Minna

    2016-01-01

    ABSTRACT The zebrafish (Danio rerio) has become a popular model for human cardiac diseases and pharmacology including cardiac arrhythmias and its electrophysiological basis. Notably, the phenotype of zebrafish cardiac action potential is similar to the human cardiac action potential in that both have a long plateau phase. Also the major inward and outward current systems are qualitatively similar in zebrafish and human hearts. However, there are also significant differences in ionic current composition between human and zebrafish hearts, and the molecular basis and pharmacological properties of human and zebrafish cardiac ionic currents differ in several ways. Cardiac ionic currents may be produced by non-orthologous genes in zebrafish and humans, and paralogous gene products of some ion channels are expressed in the zebrafish heart. More research on molecular basis of cardiac ion channels, and regulation and drug sensitivity of the cardiac ionic currents are needed to enable rational use of the zebrafish heart as an electrophysiological model for the human heart. PMID:26671745

  5. Obesity, Cardiovascular Fitness, and Inhibition Function: An Electrophysiological Study

    PubMed Central

    Song, Tai-Fen; Chi, Lin; Chu, Chien-Heng; Chen, Feng-Tzu; Zhou, Chenglin; Chang, Yu-Kai

    2016-01-01

    The purpose of the present study was to examine how obesity and cardiovascular fitness are associated with the inhibition aspect of executive function from behavioral and electrophysiological perspectives. One hundred college students, aged 18–25 years, were categorized into four groups of equal size on the basis of body mass index and cardiovascular fitness: a normal-weight and high-fitness (NH) group, an obese-weight and high-fitness (OH) group, a normal-weight and low-fitness (NL) group, and an obese-weight and low-fitness (OL) group. Behavioral measures of response time and number of errors, as well as event-related potential measures of P3 and N1, were assessed during the Stroop Task. The results revealed that, in general, the NH group exhibited shorter response times and larger P3 amplitudes relative to the NL and OL groups, wherein the OL group exhibited the longest response time in the incongruent condition. No group differences in N1 indices were also revealed. These findings suggest that the status of being both normal weight and having high cardiovascular fitness is associated with better behavioral and later stages of electrophysiological indices of cognitive function. PMID:27512383

  6. Verification of computational models of cardiac electro-physiology.

    PubMed

    Pathmanathan, Pras; Gray, Richard A

    2014-05-01

    For computational models of cardiac activity to be used in safety-critical clinical decision-making, thorough and rigorous testing of the accuracy of predictions is required. The field of 'verification, validation and uncertainty quantification' has been developed to evaluate the credibility of computational predictions. The first stage, verification, is the evaluation of how well computational software correctly solves the underlying mathematical equations. The aim of this paper is to introduce novel methods for verifying multi-cellular electro-physiological solvers, a crucial first stage for solvers to be used with confidence in clinical applications. We define 1D-3D model problems with exact solutions for each of the monodomain, bidomain, and bidomain-with-perfusing-bath formulations of cardiac electro-physiology, which allow for the first time the testing of cardiac solvers against exact errors on fully coupled problems in all dimensions. These problems are carefully constructed so that they can be easily run using a general solver and can be used to greatly increase confidence that an implementation is correct, which we illustrate by testing one major solver, 'Chaste', on the problems. We then perform case studies on calculation verification (also known as solution verification) for two specific applications. We conclude by making several recommendations regarding verification in cardiac modelling.

  7. Sensitivity of Noninvasive Cardiac Electrophysiological Imaging to Variations in Personalized Anatomical Modeling

    PubMed Central

    Wang, Linwei

    2015-01-01

    Objective Noninvasive cardiac electrophysiological (EP) imaging techniques rely on anatomically-detailed heart-torso models derived from high-quality tomographic images of individual subjects. However, anatomical modeling involves variations that lead to unresolved uncertainties in the outcome of EP imaging, bringing questions to the robustness of these methods in clinical practice. In this study, we design a systematic statistical approach to assess the sensitivity of EP imaging methods to the variations in personalized anatomical modeling. Methods We first quantify the variations in personalized anatomical models by a novel application of statistical shape modeling. Given the statistical distribution of the variation in personalized anatomical models, we then employ unscented transform to determine the sensitivity of EP imaging outputs to the variation in input personalized anatomical modeling. Results We test the feasibility of our proposed approach using two of the existing EP imaging methods: epicardial-based electrocardiographic imaging and transmural electrophysiological imaging. Both phantom and real-data experiments show that variations in personalized anatomical models have negligible impact on the outcome of EP imaging. Conclusion This study verifies the robustness of EP imaging methods to the errors in personalized anatomical modeling and suggests the possibility to simplify the process of anatomical modeling in future clinical practice. Significance This study proposes a systematic statistical approach to quantify anatomical modeling variations and assess their impact on EP imaging, which can be extended to find a balance between the quality of personalized anatomical models and the accuracy of EP imaging that may improve the clinical feasibility of EP imaging. PMID:25615906

  8. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris)

    PubMed Central

    Hunt, James; Murrell, Jo; Knazovicky, David; Harris, John; Kelly, Sara; Knowles, Toby G.; Lascelles, B. Duncan X.

    2016-01-01

    assessment of spinal nociceptive processing in dogs, without subjecting them to potentially aversive experiences. This methodology may be appropriate for obtaining electrophysiological nociceptive withdrawal reflex data in client-owned dogs with naturally occurring osteoarthritis. PMID:27433936

  9. Program Code Generator for Cardiac Electrophysiology Simulation with Automatic PDE Boundary Condition Handling

    PubMed Central

    Punzalan, Florencio Rusty; Kunieda, Yoshitoshi; Amano, Akira

    2015-01-01

    Clinical and experimental studies involving human hearts can have certain limitations. Methods such as computer simulations can be an important alternative or supplemental tool. Physiological simulation at the tissue or organ level typically involves the handling of partial differential equations (PDEs). Boundary conditions and distributed parameters, such as those used in pharmacokinetics simulation, add to the complexity of the PDE solution. These factors can tailor PDE solutions and their corresponding program code to specific problems. Boundary condition and parameter changes in the customized code are usually prone to errors and time-consuming. We propose a general approach for handling PDEs and boundary conditions in computational models using a replacement scheme for discretization. This study is an extension of a program generator that we introduced in a previous publication. The program generator can generate code for multi-cell simulations of cardiac electrophysiology. Improvements to the system allow it to handle simultaneous equations in the biological function model as well as implicit PDE numerical schemes. The replacement scheme involves substituting all partial differential terms with numerical solution equations. Once the model and boundary equations are discretized with the numerical solution scheme, instances of the equations are generated to undergo dependency analysis. The result of the dependency analysis is then used to generate the program code. The resulting program code are in Java or C programming language. To validate the automatic handling of boundary conditions in the program code generator, we generated simulation code using the FHN, Luo-Rudy 1, and Hund-Rudy cell models and run cell-to-cell coupling and action potential propagation simulations. One of the simulations is based on a published experiment and simulation results are compared with the experimental data. We conclude that the proposed program code generator can be used to

  10. Program Code Generator for Cardiac Electrophysiology Simulation with Automatic PDE Boundary Condition Handling.

    PubMed

    Punzalan, Florencio Rusty; Kunieda, Yoshitoshi; Amano, Akira

    2015-01-01

    Clinical and experimental studies involving human hearts can have certain limitations. Methods such as computer simulations can be an important alternative or supplemental tool. Physiological simulation at the tissue or organ level typically involves the handling of partial differential equations (PDEs). Boundary conditions and distributed parameters, such as those used in pharmacokinetics simulation, add to the complexity of the PDE solution. These factors can tailor PDE solutions and their corresponding program code to specific problems. Boundary condition and parameter changes in the customized code are usually prone to errors and time-consuming. We propose a general approach for handling PDEs and boundary conditions in computational models using a replacement scheme for discretization. This study is an extension of a program generator that we introduced in a previous publication. The program generator can generate code for multi-cell simulations of cardiac electrophysiology. Improvements to the system allow it to handle simultaneous equations in the biological function model as well as implicit PDE numerical schemes. The replacement scheme involves substituting all partial differential terms with numerical solution equations. Once the model and boundary equations are discretized with the numerical solution scheme, instances of the equations are generated to undergo dependency analysis. The result of the dependency analysis is then used to generate the program code. The resulting program code are in Java or C programming language. To validate the automatic handling of boundary conditions in the program code generator, we generated simulation code using the FHN, Luo-Rudy 1, and Hund-Rudy cell models and run cell-to-cell coupling and action potential propagation simulations. One of the simulations is based on a published experiment and simulation results are compared with the experimental data. We conclude that the proposed program code generator can be used to

  11. A LORETA study of mental time travel: similar and distinct electrophysiological correlates of re-experiencing past events and pre-experiencing future events.

    PubMed

    Lavallee, Christina F; Persinger, Michael A

    2010-12-01

    Previous studies exploring mental time travel paradigms with functional neuroimaging techniques have uncovered both common and distinct neural correlates of re-experiencing past events or pre-experiencing future events. A gap in the mental time travel literature exists, as paradigms have not explored the affective component of re-experiencing past episodic events; this study explored this sparsely researched area. The present study employed standardized low resolution electromagnetic tomography (sLORETA) to identify electrophysiological correlates of re-experience affect-laden and non-affective past events, as well as pre-experiencing a future anticipated event. Our results confirm previous research and are also novel in that we illustrate common and distinct electrophysiological correlates of re-experiencing affective episodic events. Furthermore, research from this experiment yields results outlining a pattern of activation in the frontal and temporal regions is correlated with the time frame of past or future events subjects imagined.

  12. Preliminary experience with use of recombinant activated factor VII to control postpartum hemorrhage in acute fatty liver of pregnancy and other pregnancy-related liver disorders.

    PubMed

    Goel, Ashish; Nair, Sukesh Chandran; Viswabandya, Auro; Masilamani, Vinodh P; Rao, Shoma V; George, Alice; Regi, Annie; Jose, Ruby; Zachariah, Uday; Subramani, Kandasamy; Eapen, C E; Chandy, George

    2013-07-01

    Control of postpartum hemorrhage is difficult in patients with coagulopathy due to acute liver failure. Recombinant activated factor VII (rFVIIa) can help in control of bleed; however, it has short duration of action (2-4 h). The study aimed to report the use of rFVIIa in this setting. We retrospectively analyzed all patients with acute liver failure secondary to pregnancy-related liver disorders who received rFVIIa for control of postpartum hemorrhage (six patients, all six met diagnostic criteria for acute fatty liver of pregnancy). One dose of rFVIIa achieved adequate control of bleeding in five patients, while one patient needed a second dose. rFVIIa administration corrected coagulopathy and significantly reduced requirement of packed red cells and other blood products. No patient had thrombotic complications. In conclusion, rFVIIa was a useful adjunct to standard management in postpartum hemorrhage secondary to acute liver failure of pregnancy-related liver disorders.

  13. [Effect of mexidol, emoxypine, and dimephosphon on electrophysiological effects of nibentan].

    PubMed

    Kotliarov, A A; Kurkina, N V; Smirnova, L E; Balykova, L A

    2002-01-01

    Mexidol, emoxypine, and dimephosphon decrease the acute toxicity of nibentan in mice. In the experiments on cats, these drugs reduced the negative dromotropic action of nibentan and prevented an increase in the effective refractory period of the atrioventricular node and ventricles, in the QT interval length, and in the ventricular excitation threshold.

  14. Electrophysiological Auditory Responses and Language Development in Infants with Periventricular Leukomalacia

    ERIC Educational Resources Information Center

    Avecilla-Ramirez, G. N.; Ruiz-Correa, S.; Marroquin, J. L.; Harmony, T.; Alba, A.; Mendoza-Montoya, O.

    2011-01-01

    This study presents evidence suggesting that electrophysiological responses to language-related auditory stimuli recorded at 46 weeks postconceptional age (PCA) are associated with language development, particularly in infants with periventricular leukomalacia (PVL). In order to investigate this hypothesis, electrophysiological responses to a set…

  15. Pontine lesions mimicking acute peripheral vestibulopathy

    PubMed Central

    Thomke, F.; Hopf, H. C.

    1999-01-01

    OBJECTIVES—Clinical signs of acute peripheral vestibulopathy (APV) were repeatedly reported with pontine lesions. The clinical relevance of such a mechanism is not known, as most studies were biased by patients with additional clinical signs of brainstem dysfunction.
METHODS—Masseter reflex (MassR), blink reflex (BlinkR), brainstem auditory evoked potentials (BAEPs), and DC electro-oculography (EOG) were tested in 232 consecutive patients with clinical signs of unilateral APV.
RESULTS—Forty five of the 232 patients (19.4%) had at least one electrophysiological abnormality suggesting pontine dysfunction mainly due to possible vertebrobasilar ischaemia (22 patients) and multiple sclerosis (eight patients). MassR abnormalities were seen in 24patients, and EOG abnormalities of saccades and following eye movements occurred in 22 patients. Three patients had BlinkR-R1 abnormalities, and one had delayed BAEP waves IV and V. Clinical improvement was almost always (32 of 34 re-examined patients) associated with improvement or normalisation of at least one electrophysiological abnormality. Brain MRI was done in 25 of the 44 patients and confirmed pontine lesions in six (two infarcts, three inflammations, one tumour).
CONCLUSIONS—Pontine dysfunction was suggested in 45 of 232 consecutive patients with clinical signs of APV on the basis of abnormal electrophysiological findings, and was mainly attributed to brainstem ischaemia and multiple sclerosis. The frequency of pontine lesions mimicking APV is underestimated if based on MRI established lesions only.

 PMID:10084533

  16. Recovery Potential After Acute Stroke

    PubMed Central

    Seitz, Rüdiger J.; Donnan, Geoffrey A.

    2015-01-01

    In acute stroke, the major factor for recovery is the early use of thrombolysis aimed at arterial recanalization and reperfusion of ischemic brain tissue. Subsequently, neurorehabilitative training critically improves clinical recovery due to augmention of postlesional plasticity. Neuroimaging and electrophysiology studies have revealed that the location and volume of the stroke lesion, the affection of nerve fiber tracts, as well as functional and structural changes in the perilesional tissue and in large-scale bihemispheric networks are relevant biomarkers of post-stroke recovery. However, associated disorders, such as mood disorders, epilepsy, and neurodegenerative diseases, may induce secondary cerebral changes or aggravate the functional deficits and, thereby, compromise the potential for recovery. PMID:26617568

  17. Electrophysiological Explorations of the Bilingual Advantage: Evidence from a Stroop Task

    PubMed Central

    Coderre, Emily L.; van Heuven, Walter J. B.

    2014-01-01

    Bilinguals have been shown to exhibit a performance advantage on executive control tasks, outperforming their monolingual counterparts. Although a wealth of research has investigated this ‘bilingual advantage’ behaviourally, electrophysiological correlates are lacking. Using EEG with a Stroop task that manipulated the stimulus onset asynchrony (SOA) of word and colour presentation, the current study addressed two facets of the bilingual advantage. The possibility that bilinguals experience superior conflict processing relative to monolinguals (a ‘conflict-specific advantage’) was investigated by comparing behavioural interference effects as well as the amplitude of the Ninc, a conflict-related ERP component occurring from approximately 300–500 ms after the onset of conflict. In contrast, the hypothesis that bilinguals experience domain-general, conflict-independent enhancements in executive processing (a ‘non-conflict-specific advantage’) was evaluated by comparing the control condition (symbol strings) between groups. There was some significant, but inconsistent, evidence for a conflict-specific bilingual advantage. In contrast, strong evidence emerged for a non-conflict-specific advantage, with bilinguals demonstrating faster RTs and reduced ERP amplitudes on control trials compared to monolinguals. Importantly, when the control stimulus was presented before the colour, ERPs to control trials revealed group differences before the onset of conflict, suggesting differences in the ability to ignore or suppress distracting irrelevant information. This indicates that bilinguals experience superior executive processing even in the absence of conflict and semantic salience, and suggests that the advantage extends to more efficient proactive management of the environment. PMID:25068723

  18. Feeding barley grain-rich diets altered electrophysiological properties and permeability of the ruminal wall in a goat model.

    PubMed

    Klevenhusen, F; Hollmann, M; Podstatzky-Lichtenstein, L; Krametter-Frötscher, R; Aschenbach, J R; Zebeli, Q

    2013-04-01

    High-producing ruminants are commonly fed large amounts of concentrate to meet their high energy demands for rapid growth or high milk production. However, this feeding strategy can severely impair rumen functioning, leading to subacute ruminal acidosis. Subacute ruminal acidosis might have consequences for electrophysiological properties by changing the net ion transfer and permeability of ruminal epithelia, which may increase the uptake of toxic compounds generated in the rumen into the systemic circulation. The objective of the present study was to investigate the effects of excessive barley feeding on the electrophysiological and barrier functions of the ruminal epithelium and serum inflammation and ketogenesis markers after a long-term feeding challenge, using growing goats as a ruminant model. A feeding trial was carried out with growing goats allocated to 1 of the 3 groups (n=5-6 animals/group), with diets consisting exclusively of hay (control diet) or hay with 30 or 60% barley grain. Samples of the ventral ruminal epithelium were taken after euthanasia and instantly subjected to Ussing chamber experiments, where electrophysiological properties of the epithelium were measured in parallel with the permeability of marker molecules of different sizes [fluorescein 5(6)-isothiocyanate and horseradish peroxidase] from luminal to apical side. Additionally, ruminal fluid and blood samples were taken at the beginning of the experiment as well as shortly before euthanasia. Ruminal fluid samples were analyzed for volatile fatty acids and pH, whereas blood samples were analyzed for lipopolysaccharide, serum amyloid A, and β-hydroxybutyrate. Electrophysiological data indicated that barley feeding increased the epithelial short-circuit current compared with the control. Tissue conductance also increased with dietary barley inclusion. As shown with both marker molecules, permeability of ruminal epithelia increased with barley inclusion in the diet. Despite a lowered

  19. Computational modeling of the human atrial anatomy and electrophysiology.

    PubMed

    Dössel, Olaf; Krueger, Martin W; Weber, Frank M; Wilhelms, Mathias; Seemann, Gunnar

    2012-08-01

    This review article gives a comprehensive survey of the progress made in computational modeling of the human atria during the last 10 years. Modeling the anatomy has emerged from simple "peanut"-like structures to very detailed models including atrial wall and fiber direction. Electrophysiological models started with just two cellular models in 1998. Today, five models exist considering e.g. details of intracellular compartments and atrial heterogeneity. On the pathological side, modeling atrial remodeling and fibrotic tissue are the other important aspects. The bridge to data that are measured in the catheter laboratory and on the body surface (ECG) is under construction. Every measurement can be used either for model personalization or for validation. Potential clinical applications are briefly outlined and future research perspectives are suggested.

  20. Electrophysiological correlates of language switching in second language learners.

    PubMed

    Van Der Meij, Maartje; Cuetos, Fernando; Carreiras, Manuel; Barber, Horacio A

    2011-01-01

    This study analyzed the electrophysiological correlates of language switching in second language learners. Participants were native Spanish speakers classified in two groups according to English proficiency (high and low). Event-related potentials (ERPs) were recorded while they read English sentences, half of which contained an adjective in Spanish in the middle of the sentence. The ERP results show the time-course of language switch processing for both groups: an initial detection of the switch driven by language-specific orthography (left-occipital N250) followed by costs at the level of the lexico-semantic system (N400), and finally a late updating or reanalysis process (LPC). In the high proficiency group, effects in the N400 time window extended to left anterior electrodes and were followed by larger LPC amplitudes at posterior sites. These differences suggest that proficiency modulates the different processes triggered by language switches.

  1. Electrophysiological assessment of amiodarone in treatment of resistant supraventricular arrhythmias.

    PubMed Central

    Rowland, E; Krikler, D M

    1980-01-01

    Oral amiodarone has been used to treat 21 patients with various supraventricular arrhythmias; 13 had Wolff-Parkinson-White syndrome, which was complicated by atrial fibrillation and re-entry atrioventricular tachycardia in four, and re-entry tachycardia alone in the other nine. The remaining eight patients had paroxysmal atrial fibrillation or flutter without pre-excitation. All were refractory to conventional treatment and had undergone intracardiac electrophysiological study. Fifteen have been controlled with amiodarone, this treatment proving most effective in atrial fibrillation or flutter with or without pre-excitation. Amiodarone was successful in only four of the nine patients with re-entry atrioventricular tachycardia. In two patients who responded well the drug had to be discontinued because of side effects. Images PMID:7426165

  2. The sense of smell in Odonata: an electrophysiological screening.

    PubMed

    Piersanti, Silvana; Frati, Francesca; Conti, Eric; Rebora, Manuela; Salerno, Gianandrea

    2014-11-01

    Volatile chemicals mediate a great range of intra- and interspecific signalling and information in insects. Olfaction has been widely investigated mostly in Neoptera while the knowledge of this sense in most basal insects such as Paleoptera (Odonata and Ephemeroptera) is still poor. In the present study we show the results of an electrophysiological screening on two model species, Libellula depressa (Libellulidae) and Ischnura elegans (Coenagrionidae), representatives of the two Odonata suborders Anisoptera and Zygoptera, with the aim to deep the knowledge on the sense of smell of this insect order. The antennal olfactory sensory neurons (OSNs) of these two species responded to the same 22 compounds (out of 48 chemicals belonging to different functional groups) encompassing mostly amines, carboxylic acids or aldehydes and belonging to green leaf volatiles, vertebrate related volatiles and volatiles emitted by standing waters bacteria. The properties of Odonata OSNs are very similar to those of ionotropic receptors (IRs) expressing OSNs in other insects.

  3. Affective Priming by Eye Gaze Stimuli: Behavioral and Electrophysiological Evidence

    PubMed Central

    Chen, Tingji; Peltola, Mikko J.; Ranta, Lotta J.; Hietanen, Jari K.

    2016-01-01

    The present study employed the affective priming paradigm and measurements of event-related potentials (ERPs) to investigate implicit affective reactions elicited by gaze stimuli. Participants categorized positive and negative words primed by direct gaze, averted gaze and closed eyes. The behavioral response time (RT) results indicated that direct gaze implicitly elicited more positive affective reactions than did closed eyes. Analyses of the ERP responses to the target words revealed a priming effect on the N170 and an interaction on late positive potential (LPP) responses, and congruently with the behavioral results, suggested that, compared to closed eyes, direct gaze was affectively more congruent with positive words and more incongruent with negative words. The priming effect on the N170 response indicated that gaze stimuli influenced the subsequent affective word processing at an early stage of information processing. In conclusion, the present behavioral and electrophysiological evidence suggests that direct gaze automatically activates more positive affective reactions than closed eyes. PMID:28003803

  4. Electrophysiological ratio markers for the balance between reward and punishment.

    PubMed

    Schutter, Dennis J L G; Van Honk, Jack

    2005-08-01

    It has been argued that prototypical forms of psychopathology result from an imbalance in reward and punishment systems. Recent studies suggest that the ratios between slower and faster waves of the electroencephalogram (EEG) index this motivational balance and might therefore have diagnostic value for psychopathology. To scrutinize this notion, the present study investigated whether resting state EEG ratios would predict decision making on the Iowa gambling task (Iowa-GT), a well-known marker for motivational imbalance. A resting state EEG recording was acquired followed by the Iowa-GT in twenty-eight healthy right-handed volunteers. Results showed that higher versus lower EEG ratios were associated with disadvantageous versus advantageous decision making strategies indicating motivational imbalances in reward- and punishment-driven behavior, respectively. This finding provides the first direct evidence that the electrophysiologically derived EEG ratios can serve as biological markers for balance and imbalance in motivation.

  5. Finding the locus of semantic satiation: an electrophysiological attempt.

    PubMed

    Frenck-Mestre, C; Besson, M; Pynte, J

    1997-05-01

    The present study examined the effect of massed repetition of an initial category name upon the subsequent semantic categorization of a target word by means of an electrophysiological measure of semantic processing: the N400. Results showed the classic N400 effect, whereby evoked potentials were more negative for targets that were not members of the repeated category than for member targets. Moreover, repetition of the category name led to an increased and sustained positivity. The N400 effect was not modified, however, by repetition. Hence, insomuch as the N400 reflects meaning integration processes, these results do not support the hypothesis that massed repetition exerts its influence at the level of meaning integration.

  6. Reentry confined to the atrioventricular node: electrophysiologic and anatomic findings.

    PubMed

    Sheinman, M M; Gonzalez, R; Thomas, A; Ullyot, D; Bharati, S; Lev, M

    1982-05-01

    A patient with recurrent disabling, paroxysmal supraventricular tachycardia refractory to drug treatment underwent electrophysiologic studies. The paroxysmal supraventricular tachycardia was found to be due to atrioventricular (A-V) nodal reentry. The patient died shortly after surgical His bundle section and detailed anatomic studies were performed. These showed fatty infiltration of the approaches to the sinoatrial node, atrial preferential pathways, and A-V node and common bundle. The A-V node was mechanically damaged and the common His bundle was completely severed. These abnormalities were clearly delineated and there was no evidence of an atrio-His bundle bypass tract to an accessory A-V node. Specifically, the central fibrous body and pars membranacea were defined and no atrial muscular fibers pierced these structures to joint the A-V bundle. It is concluded that paroxysmal supraventricular tachycardia due to A-V nodal reentry can be confined to the A-V node.

  7. The P300 as an Electrophysiological Probe of Alcohol Expectancy

    PubMed Central

    Fishman, Inna; Goldman, Mark S.; Donchin, Emanuel

    2008-01-01

    Language-based measures indicate that alcohol expectancies influence alcohol consumption. To relate these measures to brain actions that precede verbal output, the P300 component of the Event-related potentials (ERPs) was used to detect violations of individually held alcohol expectancies. As predicted, P300 amplitude elicited by negative alcohol expectancy stimuli was positively correlated with endorsement of positive/arousing alcohol expectancies on the language-based measure, such that the higher an individual's positive/arousing expectancies, the larger was the P300 elicited by negative alcohol expectancy stimuli. These results demonstrated concordance between language-based measures of alcohol expectancies and electrophysiological probes of expectancy. Although whether these expectancy processes are integral to decision pathways that influence consumption is unknown, these findings suggest that such processing can occur very quickly outside of conscious deliberation. PMID:18729689

  8. Reentrant Information Flow in Electrophysiological Rat Default Mode Network

    PubMed Central

    Jing, Wei; Guo, Daqing; Zhang, Yunxiang; Guo, Fengru; Valdés-Sosa, Pedro A.; Xia, Yang; Yao, Dezhong

    2017-01-01

    Functional MRI (fMRI) studies have demonstrated that the rodent brain shows a default mode network (DMN) activity similar to that in humans, offering a potential preclinical model both for physiological and pathophysiological studies. However, the neuronal mechanism underlying rodent DMN remains poorly understood. Here, we used electrophysiological data to analyze the power spectrum and estimate the directed phase transfer entropy (dPTE) within rat DMN across three vigilance states: wakeful rest (WR), slow-wave sleep (SWS), and rapid-eye-movement sleep (REMS). We observed decreased gamma powers during SWS compared with WR in most of the DMN regions. Increased gamma powers were found in prelimbic cortex, cingulate cortex, and hippocampus during REMS compared with WR, whereas retrosplenial cortex showed a reverse trend. These changed gamma powers are in line with the local metabolic variation of homologous brain regions in humans. In the analysis of directional interactions, we observed well-organized anterior-to-posterior patterns of information flow in the delta band, while opposite patterns of posterior-to-anterior flow were found in the theta band. These frequency-specific opposite patterns were only observed in WR and REMS. Additionally, most of the information senders in the delta band were also the receivers in the theta band, and vice versa. Our results provide electrophysiological evidence that rat DMN is similar to its human counterpart, and there is a frequency-dependent reentry loop of anterior-posterior information flow within rat DMN, which may offer a mechanism for functional integration, supporting conscious awareness. PMID:28289373

  9. Electrophysiological evaluation of oropharyngeal swallowing in myotonic dystrophy

    PubMed Central

    Ertekin, C; Yuceyar, N; Aydogdu, I; Karasoy, H

    2001-01-01

    OBJECTIVE—Oropharyngeal dysphagia is a common feature of patients with myotonic dystrophy and is not usually perceived due to their emotional deficits and lack of interest. The aim was to show the existence and frequency of subclinical electrophysiological abnormalities in oropharyngeal swallowing and to clarify the mechanisms of dysphagia in myotonic dystrophy.
METHODS—Eighteen patients with myotonic dystrophy were examined for oropharyngeal phase of swallowing by clinical and electrophysiological methods. Ten patients had dysphagia whereas 11 patients had signs and symptoms reflecting CNS involvement. Four patients with myotonia congenita and 30 healthy volunteers served as controls. Laryngeal movements were detected by means of a piezoelectric sensor. EMG activities of the submental muscle (SM-EMG) and needle EMG of the cricopharyngeal muscle of the upper eosophageal sphincter (CP-EMG) were also recorded during swallowing.
RESULTS—In about 70% of the patients with myotonic dystrophy, the existence of oropharyngeal dysphagia was indicated objectively by means of the technique of "dysphagia limit" and by clinical evaluation. Duration of the swallowing reflex as defined by the laryngeal relocation time (0-2 time interval) and submental muscle excitation as a part of the swallowing reflex (A-C interval) were significantly prolonged in patients with myotonic dystrophy, especially in dysphagic patients. Triggering time of the swallowing reflex (A-0 interval) also showed significant prolongation, especially in the patients having both dysphagia and CNS involvement. During swallowing, CP muscle activity was abnormal in 40% of the patients with myotonic dystrophy.
CONCLUSION—Both myopathic weakness and myotonia encountered in oropharyngeal muscles play an important part in the oral and the pharyngeal phases of swallowing dysfunction in myotonic dystrophy. It was also suggested that CNS involvement might contribute to the delay of the triggering of the

  10. Impact of ionic current variability on human ventricular cellular electrophysiology.

    PubMed

    Romero, Lucía; Pueyo, Esther; Fink, Martin; Rodríguez, Blanca

    2009-10-01

    Abnormalities in repolarization and its rate dependence are known to be related to increased proarrhythmic risk. A number of repolarization-related electrophysiological properties are commonly used as preclinical biomarkers of arrhythmic risk. However, the variability and complexity of repolarization mechanisms make the use of cellular biomarkers to predict arrhythmic risk preclinically challenging. Our goal is to investigate the role of ionic current properties and their variability in modulating cellular biomarkers of arrhythmic risk to improve risk stratification and identification in humans. A systematic investigation into the sensitivity of the main preclinical biomarkers of arrhythmic risk to changes in ionic current conductances and kinetics was performed using computer simulations. Four stimulation protocols were applied to the ten Tusscher and Panfilov human ventricular model to quantify the impact of +/-15 and +/-30% variations in key model parameters on action potential (AP) properties, Ca(2+) and Na(+) dynamics, and their rate dependence. Simulations show that, in humans, AP duration is moderately sensitive to changes in all repolarization current conductances and in L-type Ca(2+) current (I(CaL)) and slow component of the delayed rectifier current (I(Ks)) inactivation kinetics. AP triangulation, however, is strongly dependent only on inward rectifier K(+) current (I(K1)) and delayed rectifier current (I(Kr)) conductances. Furthermore, AP rate dependence (i.e., AP duration rate adaptation and restitution properties) and intracellular Ca(2+) and Na(+) levels are highly sensitive to both I(CaL) and Na(+)/K(+) pump current (I(NaK)) properties. This study provides quantitative insights into the sensitivity of preclinical biomarkers of arrhythmic risk to variations in ionic current properties in humans. The results show the importance of sensitivity analysis as a powerful method for the in-depth validation of mathematical models in cardiac electrophysiology.

  11. [Oral propranolol in Wolff-Parkinson-White syndrome. Electrophysiological data].

    PubMed

    Dolla, E; Levy, S; Cointe, R; Moyal, C; Bru, P; Rossi, P; Gérard, R

    1991-07-01

    The effects of oral propranolol were studied in 24 patients with the WPW syndrome. The average daily dose of propranolol was 130 +/- 24 mg administered in 3 doses over a period of 48 to 72 hours. Endocavitary electrophysiological study was performed 2 to 4 hours after the last dose. The effective anterograde refractory periods (EARP) of the accessory and normal pathways were measured before and after propranolol (and, in both studies, before and after isoproterenol). The EARP of the accessory pathway was not affected by the propranolol. However, in the 9 patients in whom its value was less than 270 ms, it increased significantly (p = 0.01). The EARP of the accessory pathway measured after administration of isoproterenol increased significantly in all patients with oral propranolol (p = 0.001). Sustained reciprocating tachycardia could be induced in 19 patients and non-sustained reciprocating tachycardia in 5 other patients during base line electrophysiological study. Oral propranolol prevented the induction of the tachycardias in 18 patients (75%), even after isoproterenol. The shortest R-R interval between two pre-excited complexes in atrial fibrillation increased after propranolol (283 +/- 45 to 343 +/- 95 ms). These results show that oral propranolol increases the EARP of the accessory pathway and the shortest R-R interval between two pre-excited complexes in atrial fibrillation in patients with short anterograde refractory periods of their accessory pathways, and is effective in preventing reciprocating tachycardia. Oral propranolol may be useful and can be used safely in patients with the Wolff-Parkinson-White syndrome.

  12. A Wireless Headstage for Combined Optogenetics and Multichannel Electrophysiological Recording.

    PubMed

    Gagnon-Turcotte, Gabriel; LeChasseur, Yoan; Bories, Cyril; Messaddeq, Younes; De Koninck, Yves; Gosselin, Benoit

    2017-02-01

    This paper presents a wireless headstage with real-time spike detection and data compression for combined optogenetics and multichannel electrophysiological recording. The proposed headstage, which is intended to perform both optical stimulation and electrophysiological recordings simultaneously in freely moving transgenic rodents, is entirely built with commercial off-the-shelf components, and includes 32 recording channels and 32 optical stimulation channels. It can detect, compress and transmit full action potential waveforms over 32 channels in parallel and in real time using an embedded digital signal processor based on a low-power field programmable gate array and a Microblaze microprocessor softcore. Such a processor implements a complete digital spike detector featuring a novel adaptive threshold based on a Sigma-delta control loop, and a wavelet data compression module using a new dynamic coefficient re-quantization technique achieving large compression ratios with higher signal quality. Simultaneous optical stimulation and recording have been performed in-vivo using an optrode featuring 8 microelectrodes and 1 implantable fiber coupled to a 465-nm LED, in the somatosensory cortex and the Hippocampus of a transgenic mouse expressing ChannelRhodospin (Thy1::ChR2-YFP line 4) under anesthetized conditions. Experimental results show that the proposed headstage can trigger neuron activity while collecting, detecting and compressing single cell microvolt amplitude activity from multiple channels in parallel while achieving overall compression ratios above 500. This is the first reported high-channel count wireless optogenetic device providing simultaneous optical stimulation and recording. Measured characteristics show that the proposed headstage can achieve up to 100% of true positive detection rate for signal-to-noise ratio (SNR) down to 15 dB, while achieving up to 97.28% at SNR as low as 5 dB. The implemented prototype features a lifespan of up to 105

  13. Simultaneous FMRI and electrophysiology in the rodent brain.

    PubMed

    Pan, Wen-ju; Thompson, Garth; Magnuson, Matthew; Majeed, Waqas; Jaeger, Dieter; Keilholz, Shella

    2010-08-19

    To examine the neural basis of the blood oxygenation level dependent (BOLD) magnetic resonance imaging (MRI) signal, we have developed a rodent model in which functional MRI data and in vivo intracortical recording can be performed simultaneously. The combination of MRI and electrical recording is technically challenging because the electrodes used for recording distort the MRI images and the MRI acquisition induces noise in the electrical recording. To minimize the mutual interference of the two modalities, glass microelectrodes were used rather than metal and a noise removal algorithm was implemented for the electrophysiology data. In our studies, two microelectrodes were separately implanted in bilateral primary somatosensory cortices (SI) of the rat and fixed in place. One coronal slice covering the electrode tips was selected for functional MRI. Electrode shafts and fixation positions were not included in the image slice to avoid imaging artifacts. The removed scalp was replaced with toothpaste to reduce susceptibility mismatch and prevent Gibbs ringing artifacts in the images. The artifact structure induced in the electrical recordings by the rapidly-switching magnetic fields during image acquisition was characterized by averaging all cycles of scans for each run. The noise structure during imaging was then subtracted from original recordings. The denoised time courses were then used for further analysis in combination with the fMRI data. As an example, the simultaneous acquisition was used to determine the relationship between spontaneous fMRI BOLD signals and band-limited intracortical electrical activity. Simultaneous fMRI and electrophysiological recording in the rodent will provide a platform for many exciting applications in neuroscience in addition to elucidating the relationship between the fMRI BOLD signal and neuronal activity.

  14. Impact of service redesign on the socioeconomic inequity in revascularisation rates for patients with acute myocardial infarction: a natural experiment and electronic record-linked cohort study

    PubMed Central

    Evans, Lloyd W; van Woerden, Hugo; Fone, David

    2016-01-01

    Aim To investigate the impact of service redesign in the provision of revascularisation procedures on the historical socioeconomic inequity in revascularisation rates for patients with acute myocardial infarction (AMI). Design Natural experiment and retrospective cohort study using linked data sets in the Secure Anonymised Information Linkage databank. Non-randomised intervention An increase in the capacity of revascularisation procedures and service redesign in the provision of revascularisation in late 2011 to early 2012. Setting South Wales cardiac network, Census 2011 population 1 359 051 aged 35 years and over. Participants 9128 participants admitted to an NHS hospital with a first AMI between 1 January 2010 and 30 June 2013, with 6-months follow-up. Main outcome measure Hazard ratios (HRs) for the time to revascularisation for deprivation quintiles, age, gender, comorbidities, rural–urban classification and revascularisation facilities of admitting hospital. Results In the preintervention period, there was a statistically significant decreased adjusted risk of revascularisation for participants in the most deprived quintile compared to the least deprived quintile (HR 0.80; 95% CI 0.69 to 0.92, p=0.002). In the postintervention period, the increase in revascularisation rates was statistically significant in all quintiles, and there was no longer any statistically significant difference in the adjusted revascularisation risk between the most and the least deprived quintile (HR 1.04; 95% CI 0.89 to 1.20, p<0.649). However, inequity persisted for those aged 75 years and over (HR 0.40; 95% CI 0.35 to 0.46, p<0.001) and women (HR 0.77; 95% CI 0.70 to 0.86, p<0.001). Conclusions Socioeconomic inequity of access to revascularisation was no longer apparent following redesign of revascularisation services in the south Wales cardiac network, although inequity persisted for women and those aged 75+ years. Increasing the capacity of revascularisation did not

  15. Pathophysiology of acute pancreatitis.

    PubMed

    Bhatia, Madhav; Wong, Fei Ling; Cao, Yang; Lau, Hon Yen; Huang, Jiali; Puneet, Padmam; Chevali, Lakshmi

    2005-01-01

    Acute pancreatitis is a common clinical condition. It is a disease of variable severity in which some patients experience mild, self-limited attacks while others manifest a severe, highly morbid, and frequently lethal attack. The exact mechanisms by which diverse etiological factors induce an attack are still unclear. It is generally believed that the earliest events in acute pancreatitis occur within acinar cells. Acinar cell injury early in acute pancreatitis leads to a local inflammatory reaction. If this inflammatory reaction is marked, it leads to a systemic inflammatory response syndrome (SIRS). An excessive SIRS leads to distant organ damage and multiple organ dysfunction syndrome (MODS). MODS associated with acute pancreatitis is the primary cause of morbidity and mortality in this condition. Recent studies have established the role played by inflammatory mediators in the pathogenesis of acute pancreatitis and the resultant MODS. At the same time, recent research has demonstrated the importance of acinar cell death in the form of apoptosis and necrosis as a determinant of pancreatitis severity. In this review, we will discuss about our current understanding of the pathophysiology of acute pancreatitis.

  16. Electrophysiological responses to symmetry presented in the left or in the right visual hemifield.

    PubMed

    Wright, Damien; Makin, Alexis D J; Bertamini, Marco

    2017-01-01

    Symmetry is a highly salient feature in the visual world, abundant in both man-made and natural objects. In particular, humans find reflectional symmetry most salient. Electrophysiological work on symmetry perception has identified a difference wave known as the Sustained Posterior Negativity (SPN) originating from extrastriate areas. Amplitude is more negative for symmetrical than random patterns, from around 200 msec after stimulus onset. For the first time, we report responses to patterns presented exclusively in one hemifield. Participants were presented with reflection or random dot patterns to the left and right of fixation (3.2°). They judged whether the patterns were light red or dark red in colour. In Experiment 1, the pair always included one symmetrical and one random pattern. In Experiments 2 and 3 we varied the information presented contralaterally. The SPN was generated separately in each hemisphere in response to what was presented in the contralateral visual hemifield (a lateralised SPN). We conclude that a symmetry-sensitive network of extrastriate areas can be activated independently in each cerebral hemisphere.

  17. Exploring emotions using invasive methods: review of 60 years of human intracranial electrophysiology

    PubMed Central

    Guillory, Sean A.

    2014-01-01

    Over the past 60 years, human intracranial electrophysiology (HIE) has been used to characterize seizures in patients with epilepsy. Secondary to the clinical objectives, electrodes implanted intracranially have been used to investigate mechanisms of human cognition. In addition to studies of memory and language, HIE methods have been used to investigate emotions. The aim of this review is to outline the contribution of HIE (electrocorticography, single-unit recording and electrical brain stimulation) to our understanding of the neural representations of emotions. We identified 64 papers dating back to the mid-1950s which used HIE techniques to study emotional states. Evidence from HIE studies supports the existence of widely distributed networks in the neocortex, limbic/paralimbic regions and subcortical nuclei which contribute to the representation of emotional states. In addition, evidence from HIE supports hemispheric dominance for emotional valence. Furthermore, evidence from HIE supports the existence of overlapping neural areas for emotion perception, experience and expression. Lastly, HIE provides unique insights into the temporal dynamics of neural activation during perception, experience and expression of emotional states. In conclusion, we propose that HIE techniques offer important evidence which must be incorporated into our current models of emotion representation in the human brain. PMID:24509492

  18. Closed-Loop, Multichannel Experimentation Using the Open-Source NeuroRighter Electrophysiology Platform

    PubMed Central

    Newman, Jonathan P.; Zeller-Townson, Riley; Fong, Ming-Fai; Arcot Desai, Sharanya; Gross, Robert E.; Potter, Steve M.

    2013-01-01

    Single neuron feedback control techniques, such as voltage clamp and dynamic clamp, have enabled numerous advances in our understanding of ion channels, electrochemical signaling, and neural dynamics. Although commercially available multichannel recording and stimulation systems are commonly used for studying neural processing at the network level, they provide little native support for real-time feedback. We developed the open-source NeuroRighter multichannel electrophysiology hardware and software platform for closed-loop multichannel control with a focus on accessibility and low cost. NeuroRighter allows 64 channels of stimulation and recording for around US $10,000, along with the ability to integrate with other software and hardware. Here, we present substantial enhancements to the NeuroRighter platform, including a redesigned desktop application, a new stimulation subsystem allowing arbitrary stimulation patterns, low-latency data servers for accessing data streams, and a new application programming interface (API) for creating closed-loop protocols that can be inserted into NeuroRighter as plugin programs. This greatly simplifies the design of sophisticated real-time experiments without sacrificing the power and speed of a compiled programming language. Here we present a detailed description of NeuroRighter as a stand-alone application, its plugin API, and an extensive set of case studies that highlight the system’s abilities for conducting closed-loop, multichannel interfacing experiments. PMID:23346047

  19. Electrophysiological analysis of the role of novelty in the von Restorff effect

    PubMed Central

    Rangel-Gomez, Mauricio; Meeter, Martijn

    2013-01-01

    Items that are distinctive with respect to their context tend to be recalled better than nondistinctive items, a finding known as the von Restorff effect. The goal of this study was to elucidate the role of novelty in this effect. In two experiments, participants performed a dual task in which they had to study words presented visually while to-be ignored sounds were played over earphones. Sounds could be either standard or novel, and words could be presented in standard or novel font. Sounds were presented either simultaneously with the words (Experiment 1) or preceding them (Experiment 2). Electrophysiological correlates of novelty processing, the N2b and P3a ERP components, were recorded while the words were studied. It was seen that cued recall was better for words presented in novel fonts than for words in a standard font (the von Restorff effect). Words presented while novel sounds were played were remembered worse (Experiment 1) or equally well (Experiment 2) than those combined with standard sounds. Words presented in novel fonts elicited enhanced N2b, P3a, P3b, and N400 components; however, none of these components were specifically larger for subsequently recalled novel-font words. A larger N2b was found for recalled than for nonrecalled words, but this effect was not specific for words presented in novel font. We hypothesized that if novelty was beneficial for memory processing, the N2–P3 complex would be more enhanced for novel words that were later recalled than for those not recalled. The data showed otherwise. This suggests that novelty processing, as indexed by the N2–P3 novelty components, is not the main cause of the von Restorff effect. PMID:23531713

  20. Electrophysiological impact of trazodone on the dopamine and norepinephrine systems in the rat brain.

    PubMed

    Ghanbari, Ramez; El Mansari, Mostafa; Blier, Pierre

    2012-07-01

    Previous study has documented the long-term effects of the antidepressant trazodone on the serotonin (5-HT) system. The present work examined the impact of sustained trazodone on ventral tegmental area (VTA) dopamine (DA) and locus ceruleus (LC) norepinephrine (NE) neurons firing activity, and characterized its effects at 5-HT(2C), 5-HT(2A) receptors and α₁- and α₂-adrenoceptors. Electrophysiological recordings were carried out in anesthetized rats. Subcutaneously implanted minipumps delivered vehicle or trazodone (10 mg/kg/day) for 2 or 14 days. Administration of trazodone for 2 and 14 days did not alter the firing activity of DA neurons. Systemic injection of trazodone, however, reversed the inhibitory effect of the 5-HT(2C) receptor agonist Ro 60,0175 on the DA neuronal firing, suggesting an antagonistic action of trazodone at this receptor. Administration of trazodone for 2 days significantly enhanced the NE neurons firing. Despite a return of the NE neurons firing rate to the baseline following 14-day trazodone, the percentage of neurons discharging in burst was increased by this regimen. Administration of trazodone for 14 days enhanced the tonic activation of postsynaptic α₂-adrenoceptors, as indicated by the disinhibitory effect of the α₂-adrenoceptor antagonist idazoxan on hippocampus pyramidal neurons firing. The inhibitory effect of acute trazodone on dorsal raphe (DR) 5-HT neurons firing was shown to be through the 5-HT(1A) receptor. Systemic injection of trazodone reversed the inhibitory action of 5-HT(2A) agonist DOI on the NE neurons firing rate, indicating its antagonistic action at 5-HT(2A) receptors. The enhancement in α₂-adrenergic transmission by trazodone, and its 5-HT(2A) and 5-HT(2C) receptor antagonism may contribute to its therapeutic action in major depression.

  1. Altered Calcium Handling and Ventricular Arrhythmias in Acute Ischemia

    PubMed Central

    Baumeister, Peter; Quinn, T. Alexander

    2016-01-01

    Acute ischemia results in deadly cardiac arrhythmias that are a major contributor to sudden cardiac death (SCD). The electrophysiological changes involved have been extensively studied, yet the mechanisms of ventricular arrhythmias during acute ischemia remain unclear. What is known is that during acute ischemia both focal (ectopic excitation) and nonfocal (reentry) arrhythmias occur, due to an interaction of altered electrical, mechanical, and biochemical properties of the myocardium. There is particular interest in the role that alterations in intracellular calcium handling, which cause changes in intracellular calcium concentration and to the calcium transient, play in ischemia-induced arrhythmias. In this review, we briefly summarize the known contributors to ventricular arrhythmias during acute ischemia, followed by an in-depth examination of the potential contribution of altered intracellular calcium handling, which may include novel targets for antiarrhythmic therapy. PMID:28008297

  2. Comparison of two electrophysiological methods for the assessment of progress in a rat model of nerve repair

    PubMed Central

    Han, Dong; Lu, Jiuzhou; Xu, Lei; Xu, Jianguang

    2015-01-01

    There are 2 critical steps in neural regeneration: nerve fibres successfully crossing the suture and restoration of neuromuscular transmission. For the second step, the compound muscle action potential (CMAP) is the standard electrophysiological technique used to assess regeneration, but it is difficult to detect changes in the CMAP during early regeneration after nerve repair. There is a need for better, noninvasive quantitative electrophysiological techniques to assess regeneration in an earlier stage after nerve repair. In this study, we utilized 2 measures, CMAP and single-fibre electromyography (SFEMG), in a rat model of nerve repair. The model was generated by separating the sciatic nerve of the rat hindlimb from the tibial nerve in Sprague-Dawley rats. CMAP and SFEMG were measured in each rat at 1, 2, 3, 4, and 6 weeks after the operation. The muscle weight was measured and both the general structure of the muscle and the changes in muscle atrophy were examined using haematoxylin and eosin staining protocols. The nerve electrophysiological data could be detected at 2 weeks after surgery initially and more data could be collected with passing time. During the period ranging from 2 to 4 weeks after surgery, parameters of SFEMG recordings changed significantly while the CMAP amplitude did not increase until 6 weeks after surgery. While the fibre density (FD) at 2 weeks after surgery was 0.27 ± 0.31, there was a significant increase at 3 weeks relative to 2 weeks (P < 0.01), and the FD increased further at 4 weeks (P < 0.01). The action potential mean consecutive difference (MCD) was significantly higher (60.50 ± 3.53 μs) in the second week relative to the third week (41.12 ± 5.08 μs) after the operation. The results indicated that SFEMG was more sensitive than CMAP amplitudes in detecting neuromuscular transmission after nerve repair. The findings of nerve electrophysiological experiments were consistent with the observed degree of muscle recovery. The

  3. An objective electrophysiological marker of face individualisation impairment in acquired prosopagnosia with fast periodic visual stimulation.

    PubMed

    Liu-Shuang, Joan; Torfs, Katrien; Rossion, Bruno

    2016-03-01

    One of the most striking pieces of evidence for a specialised face processing system in humans is acquired prosopagnosia, i.e. the inability to individualise faces following brain damage. However, a sensitive and objective non-behavioural marker for this deficit is difficult to provide with standard event-related potentials (ERPs), such as the well-known face-related N170 component reported and investigated in-depth by our late distinguished colleague Shlomo Bentin. Here we demonstrate that fast periodic visual stimulation (FPVS) in electrophysiology can quantify face individualisation impairment in acquired prosopagnosia. In Experiment 1 (Liu-Shuang et al., 2014), identical faces were presented at a rate of 5.88 Hz (i.e., ≈ 6 images/s, SOA=170 ms, 1 fixation per image), with different faces appearing every 5th face (5.88 Hz/5=1.18 Hz). Responses of interest were identified at these predetermined frequencies (i.e., objectively) in the EEG frequency-domain data. A well-studied case of acquired prosopagnosia (PS) and a group of age- and gender-matched controls completed only 4 × 1-min stimulation sequences, with an orthogonal fixation cross task. Contrarily to controls, PS did not show face individualisation responses at 1.18 Hz, in line with her prosopagnosia. However, her response at 5.88 Hz, reflecting general visual processing, was within the normal range. In Experiment 2 (Rossion et al., 2015), we presented natural (i.e., unsegmented) images of objects at 5.88 Hz, with face images shown every 5th image (1.18 Hz). In accordance with her preserved ability to categorise a face as a face, and despite extensive brain lesions potentially affecting the overall EEG signal-to-noise ratio, PS showed 1.18 Hz face-selective responses within the normal range. Collectively, these findings show that fast periodic visual stimulation provides objective and sensitive electrophysiological markers of preserved and impaired face processing abilities in the neuropsychological

  4. Effect of phenylephrine infusion on atrial electrophysiological properties.

    PubMed Central

    Leitch, J. W.; Basta, M.; Fletcher, P. J.

    1997-01-01

    OBJECTIVE: To determine the effect of changes in autonomic tone induced by phenylephrine infusion on atrial refractoriness and conduction. DESIGN: Left and right atrial electrophysiological properties were measured before and after a constant phenylephrine infusion designed to increase sinus cycle length by 25%. SUBJECTS: 20 patients, aged 53 (SD 6) years, undergoing electrophysiological study for investigation of idiopathic paroxysmal atrial fibrillation (seven patients) or for routine follow up after successful catheter ablation of supraventricular tachycardia (13 patients). MAIN OUTCOME MEASURES: Changes in left and right atrial effective refractory periods, atrial activation times, and frequency of induction of atrial fibrillation. RESULTS: Phenylephrine (mean dose 69 (SD 18) mg/min) increased mean blood pressure by 22 (12) mm Hg (range 7 to 44) and lengthened sinus cycle length by 223 (94) ms (20 to 430). Left atrial effective refractory period lengthened following phenylephrine infusion from 250 (25) to 264 (21) ms (P < 0.001) but there was no significant change in right atrial effective refractory period: 200 (20) v 206 (29), P = 0.11. There was a significant relation between the effect of phenylephrine on sinus cycle length and on right atrial refractoriness (r = 0.6, P = 0.005) with shortening of right atrial refractoriness in patients with the greatest prolongation in sinus cycle length. During phenylephrine infusion, the right atrial stimulus to left atrial activation time at the basic pacing cycle length of 600 ms was unchanged, at 130 (18) v 131 (17) ms, but activation delay with a premature extrastimulus increased: 212 (28) v 227 (38) ms, P = 0.002. Atrial fibrillation was induced by two of 58 refractory period measurements at baseline and by 12 of 61 measurements during phenylephrine infusion (P < 0.01). Phenylephrine increased the difference between left and right atrial refractory periods by 22.8 (19.4) ms in the five patients with induced atrial

  5. Electrophysiology of regular firing cells in the rat perirhinal cortex.

    PubMed

    D'Antuono, M; Biagini, G; Tancredi, V; Avoli, M

    2001-01-01

    The electrophysiological properties of neurons in the rat perirhinal cortex were analyzed with intracellular recordings in an in vitro slice preparation. Cells included in this study (n = 59) had resting membrane potential (RMP) = -73.9 +/- 8.5 mV (mean +/- SD), action potential amplitude = 95.5 +/- 10.4 mV, input resistance = 36.1 +/- v 15.7 M omega, and time constant = 13.9 +/- 3.4 ms. When filled with neurobiotin (n = 27) they displayed a pyramidal shape with an apical dendrite and extensive basal dendritic tree. Injection of intracellular current pulses revealed: 1) a tetrodotoxin (TTX, 1 microM)-sensitive, inward rectification in the depolarizing direction (n = 6), and 2) a time- and voltage-dependent hyperpolarizing sag that was blocked by extracellular Cs+ (3 mM, n = 5) application. Prolonged (up to 3 s) depolarizing pulses made perirhinal cells discharge regular firing of fast action potentials that diminished over time in frequency and reached a steady level (i.e., adapted). Repetitive firing was followed by an afterhyperpolarization that was decreased, along with firing adaptation, by the Ca(2+)-channel blocker Co2+ (2 mM, n = 6). Action potential broadening became evident during repetitive firing. This behavior, which was more pronounced when larger pulses of depolarizing current were injected (and thus when repetitive firing attained higher rates), was markedly decreased by Co2+ application. Subthreshold membrane oscillations at 5-12 Hz became apparent when cells were depolarized by 10-20 mV from RMP, and action potential clusters appeared with further depolarization. Application of glutamatergic and GABAA receptor antagonists (n = 4), CO2+ (n = 6), or Cs+ (n = 5) did not prevent the occurrence of these oscillations that were abolished by TTX (n = 6). Our results show that pyramidal-like neurons in the perirhinal cortex are regular firing cells with electrophysiological features resembling those of other cortical pyramidal elements. The ability to

  6. Active sodium transport and the electrophysiology of rabbit colon.

    PubMed

    Schultz, S G; Frizzell, R A; Nellans, H N

    1977-05-12

    The electrophysiologic properties of rabbit colonic epithelial cells were investigated employing microelectrode techniques. Under open-circuit conditions, the transepithelial electrical potential difference (PD) averaged 20 mV, serosa positive, and the intracellular electrical potential (psimc) averaged -32 mV, cell interior negative with respect to the mucosal solution; under short-circuit conditions, psimc averaged -46 mV. The addition of amiloride to the mucosal solution abolishes the transepithelial PD and active Na transport, and psimc is hyperpolarized to an average value of -53 mV. These results indicate that Na entry into the mucosal cell is a conductive process which, normally, depolarized psimc. The data obtained were interpreted using a double-membrane equivalent electrical circuit model of the "active Na transport pathway" involving two voltage-independent electromotive forces (emf's) and two voltage-independent resistances arrayed in series. Our observations are consistent with the notions that: (a) The emf's and resistances across the mucosal and baso-lateral membranes are determined predominantly by the emf (64 mV) and resistance of the Na entry process and the emf (53 mV) and resistance of the process responsible for active Na extrusion across the baso-lateral membranes: that is, the electrophysiological properties of the cell appear to be determined solely by the properties and processes responsible for transcellular active Na transport. The emf of the Na entry process is consistent with the notion that the Na activity in the intracellular transport pool is approximately one-tenth that in the mucosal solution or about 14 mM. (b) In the presence of amiloride, the transcellular conductance is essentially abolished and the total tissue conductance is the result of ionic diffusion through paracellular pathways. (c) The negative intracellular potential (with respect to the mucosal solution) is due primarily to the presence of a low resistance

  7. Electrophysiological characteristics of enteric neurons isolated from the Immortomouse

    PubMed Central

    Hawkins, Edward G.; Dewey, William L.; Anitha, Mallappa; Srinivasan, Shanthi; Grider, John R.; Akbarali, Hamid I.

    2013-01-01

    Background Recently two enteric neuronal cell lines, one fetal (IM-FEN) and the other post-natal (IM-PEN), have been developed from the H-2Kb-tsA58 transgenic mouse (immortomouse). However, their electrophysiological properties are not known. The goal of this study was to determine the electrical excitability and ionic conductance of the immortalized postnatal enteric neuronal (IM-PEN) cell line. Methods Whole cell patch clamp studies, immunohistochemistry and RT-PCR were performed on differentiated IM-PEN cells following propagation at 33°C and differentiation at 37°C. Results Differentiated IM-PEN cells stained positively for the neuron specific markers βIII-tubulin and PGP9.5. The mRNA for several ion channels expressed in enteric neurons were detected by RT-PCR. In current clamp, the resting membrane potential was −24.6 ± 2.1mV (n=6) for IM-FEN and −29.8 ± 0.9mV (n=30) for IM-PEN. Current injections from Vh −80 mV, resulted in passive responses but not action potentials. Depolarizing pulses in the whole cell voltage clamp configuration from Vh −80 mV elicited small nifedipine-sensitive inward currents. Additionally, outward currents with slow deactivating tail currents were blocked by niflumic acid and low chloride solution. A volume-regulated anion current was elicited by hypo-osmotic solution and inhibited by 10μM DCPIB. Growth with rabbit gastrointestinal smooth muscle did not yield significant differences in the active properties of the IM-PEN cell line. Transient expression of L-type Ca2+ channels produced large inward currents demonstrating a working mechanism for protein folding and transport. Conclusion The electrophysiological characteristics of IM-PEN cells suggest that chloride channels in IM-PEN cells play an important role in their resting state and membrane trafficking of some of the ion channels may preclude their electrical excitability. PMID:23371009

  8. Acute Pancreatitis and Pregnancy

    MedlinePlus

    ... Pancreatitis Acute Pancreatitis and Pregnancy Acute Pancreatitis and Pregnancy Timothy Gardner, MD Acute pancreatitis is defined as ... pancreatitis in pregnancy. Reasons for Acute Pancreatitis and Pregnancy While acute pancreatitis is responsible for almost 1 ...

  9. Design, Fabrication and Characterization of a Low-Impedance 3D Electrode Array System for Neuro-Electrophysiology

    PubMed Central

    Kusko, Mihaela; Craciunoiu, Florea; Amuzescu, Bogdan; Halitzchi, Ferdinand; Selescu, Tudor; Radoi, Antonio; Popescu, Marian; Simion, Monica; Bragaru, Adina; Ignat, Teodora

    2012-01-01

    Recent progress in patterned microelectrode manufacturing technology and microfluidics has opened the way to a large variety of cellular and molecular biosensor-based applications. In this extremely diverse and rapidly expanding landscape, silicon-based technologies occupy a special position, given their statute of mature, consolidated, and highly accessible areas of development. Within the present work we report microfabrication procedures and workflows for 3D patterned gold-plated microelectrode arrays (MEA) of different shapes (pyramidal, conical and high aspect ratio), and we provide a detailed characterization of their physical features during all the fabrication steps to have in the end a reliable technology. Moreover, the electrical performances of MEA silicon chips mounted on standardized connector boards via ultrasound wire-bonding have been tested using non-destructive electrochemical methods: linear sweep and cyclic voltammetry, impedance spectroscopy. Further, an experimental recording chamber package suitable for in vitro electrophysiology experiments has been realized using custom-design electronics for electrical stimulus delivery and local field potential recording, included in a complete electrophysiology setup, and the experimental structures have been tested on newborn rat hippocampal slices, yielding similar performance compared to commercially available MEA equipments. PMID:23208555

  10. Effectiveness of a Forward Collision Warning System in simple and in dual task from an electrophysiological perspective.

    PubMed

    Bueno, Mercedes; Fort, Alexandra; Francois, Mathilde; Ndiaye, Daniel; Deleurence, Philippe; Fabrigoule, Colette

    2013-04-29

    Forward Collision Warning Systems (FCWS) are expected to assist drivers; however, it is not completely clear whether these systems are of benefit to distracted drivers as much as they are to undistracted drivers. This study aims at investigating further the analysis of the effectiveness of a surrogate FCWS according to the attentional state of participants. In this experiment electrophysiological and behavioural data were recording while participants were required to drive in a simple car simulator and to react to the braking of the lead vehicle which could be announced by a warning system. The effectiveness of this warning system was evaluated when drivers were distracted or not by a secondary cognitive task. In a previous study, the warning signal was not completely effective likely due to the presence of another predictor of the forthcoming braking which competes with the warning. By eliminating this secondary predictor in the present study, the results confirmed the negative effect of the secondary task and revealed the expected effectiveness of the warning system at behavioural and electrophysiological levels.

  11. Retinal Electrophysiology Is a Viable Preclinical Biomarker for Drug Penetrance into the Central Nervous System

    PubMed Central

    Charng, Jason; He, Zheng; Vingrys, Algis J.; Fish, Rebecca L.; Gurrell, Rachel; Bui, Bang V.; Nguyen, Christine T.

    2016-01-01

    Objective. To examine whether retinal electrophysiology is a useful surrogate marker of drug penetrance into the central nervous system (CNS). Materials and Methods. Brain and retinal electrophysiology were assessed with full-field visually evoked potentials and electroretinograms in conscious and anaesthetised rats following systemic or local administrations of centrally penetrant (muscimol) or nonpenetrant (isoguvacine) compounds. Results. Local injections into the eye/brain bypassed the blood neural barriers and produced changes in retinal/brain responses for both drugs. In conscious animals, systemic administration of muscimol resulted in retinal and brain biopotential changes, whereas systemic delivery of isoguvacine did not. General anaesthesia confounded these outcomes. Conclusions. Retinal electrophysiology, when recorded in conscious animals, shows promise as a viable biomarker of drug penetration into the CNS. In contrast, when conducted under anaesthetised conditions confounds can be induced in both cortical and retinal electrophysiological recordings. PMID:27239335

  12. Treatment-related myelodysplastic syndrome (t-MDS)/acute myeloid leukemia (AML) in children with cancer: A single-center experience.

    PubMed

    Tragiannidis, Athanasios; Gombakis, Nikolaos; Papageorgiou, Maria; Hatzipantelis, Emmanuel; Papageorgiou, Theodotis; Hatzistilianou, Maria

    2016-12-01

    Treatment-related myelodysplastic syndrome (t-MDS)/acute myeloid leukemia (AML) is a devastating early or late complication of treatment for childhood cancer related with a significant morbidity and mortality. We retrospectively studied survivors of childhood cancer. Overall, 287 patients were recorded in the databases and we identified three (1.04%) with t-MDS. The primary cancer diagnoses were Langerhans cell histiocytosis (one patient) and acute lymphoblastic leukemia (ALL; two patients). The mean age of patients was 12.1 years. All patients had received systemic antifungal treatment for invasive pulmonary aspergillosis successfully treated with voriconazole and liposomal amphotericin B before diagnosis of t-MDS. Two patients (66%) remain alive after a median follow-up period of 3.5 years.

  13. Differential Electrophysiological Responses to Odorant Isotopologues in Drosophilid Antennae123

    PubMed Central

    Drimyli, Efstathia; Gaitanidis, Alexandros; Maniati, Klio; Turin, Luca

    2016-01-01

    Abstract Olfaction presents the ultimate challenge to molecular recognition as thousands of molecules have to be recognized by far fewer olfactory receptors. We have presented evidence that Drosophila readily distinguish odorants based on their molecular vibrations using a battery of behavioral assays suggesting engagement of a molecular vibration-sensing component. Here we interrogate electrophysiologically the antennae of four Drosophilids and demonstrate conserved differential response amplitudes to aldehydes, alcohols, ketones, nitriles, and their deuterated isotopologues. Certain deuterated odorants evoked larger electroantennogram (EAG) amplitudes, while the response to the normal odorant was elevated in others. Significantly, benzonitrile isotopologues were not distinguishable as predicted. This suggests that isotopologue-specific EAG amplitudes result from differential activation of specific olfactory receptors. In support of this, odorants with as few as two deuteria evoke distinct EAG amplitudes from their normal isotopologues, and this is independent of the size of the deuterated molecule. Importantly, we find no evidence that these isotopologue-specific amplitudes depend on perireceptor mechanisms or other pertinent physical property of the deuterated odorants. Rather, our results strongly suggest that Drosophilid olfactory receptors are activated by molecular vibrations differentiating similarly sized and shaped odorants in vivo, yielding sufficient differential information to drive behavioral choices. PMID:27351023

  14. Effects of context on electrophysiological response to musical accents.

    PubMed

    Palmer, Caroline; Jewett, Lisa R; Steinhauer, Karsten

    2009-07-01

    Listeners' aesthetic and emotional responses to music typically occur in the context of long musical passages that contain structures defined in terms of the events that precede them. We describe an electrophysiological study of listeners' brain responses to musical accents that coincided in longer musical sequences. Musically trained listeners performed a timbre-change detection task in which a single-tone timbre change was positioned within 4-bar melodies composed of 350-ms tones to coincide or not with melodic contour accents and temporal accents (induced with temporal gaps). Event-related potential responses to (task-relevant) attended timbre changes elicited an early negativity (MMN/N2b) around 200 ms and a late positive component around 350 ms (P300), reflecting updating of the timbre change in working memory. The amplitudes of both components changed systematically across the sequence, consistent with expectancy-based context effects. Furthermore, melodic contour changes modulated the MMN/N2b response (but not the P300) to timbre changes in later sequence positions. In contrast, task-irrelevant temporal gaps elicited an MMN that was not modulated by position within the context; absence of a P300 indicated that temporal-gap accents were not updated in working memory. Listeners' neural responses to musical structure changed systematically as sequential predictability and listeners' expectations changed across the melodic context.

  15. The Electrophysiological Underpinnings of Processing Gender Stereotypes in Language

    PubMed Central

    Siyanova-Chanturia, Anna; Pesciarelli, Francesca; Cacciari, Cristina

    2012-01-01

    Despite the widely documented influence of gender stereotypes on social behaviour, little is known about the electrophysiological substrates engaged in the processing of such information when conveyed by language. Using event-related brain potentials (ERPs), we examined the brain response to third-person pronouns (lei “she” and lui “he”) that were implicitly primed by definitional (passeggeraFEM “passenger”, pensionatoMASC “pensioner”), or stereotypical antecedents (insegnante “teacher”, conducente “driver”). An N400-like effect on the pronoun emerged when it was preceded by a definitionally incongruent prime (passeggeraFEM – lui; pensionatoMASC – lei), and a stereotypically incongruent prime for masculine pronouns only (insegnante – lui). In addition, a P300-like effect was found when the pronoun was preceded by definitionally incongruent primes. However, this effect was observed for female, but not male participants. Overall, these results provide further evidence for on-line effects of stereotypical gender in language comprehension. Importantly, our results also suggest a gender stereotype asymmetry in that male and female stereotypes affected the processing of pronouns differently. PMID:23226494

  16. Filial versus romantic love: contributions from peripheral and central electrophysiology.

    PubMed

    Guerra, Pedro; Campagnoli, Rafaela R; Vico, Cynthia; Volchan, Eliane; Anllo-Vento, Lourdes; Vila, Jaime

    2011-12-01

    A major problem in recent neuroscience research on the processing of loved familiar faces is the absence of evidence concerning the elicitation of a genuine positive emotional response (love). These studies have two confounds: familiarity and arousal. The present investigation controlled for both factors in female university students. Two categories of loved faces were chosen: one with higher familiarity but lower emotionality (fathers) and the other with higher emotionality but lower familiarity (romantic partners). Unfamiliar and baby faces were used as control faces. Central and peripheral electrophysiological measures as well as subjective indices of valence, arousal, and dominance were recorded. Results support the conclusion that viewing loved familiar faces elicits an intense positive emotional reaction that cannot be explained either by familiarity or arousal. The differences between romantic and filial love appeared in the magnitude of some peripheral and subjective indices of emotionality (zygomatic activity, valence, arousal, and dominance), that were higher for images of the romantic partners, and one central index of familiarity (the P3 amplitude), that was higher for images of the fathers.

  17. Multifunctional Catheters Combining Intracardiac Ultrasound Imaging and Electrophysiology Sensing

    PubMed Central

    Stephens, Douglas N.; Cannata, Jonathan; Liu, Ruibin; Zhao, Jian Zhong; Shung, K. Kirk; Nguyen, Hien; Chia, Raymond; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai E.; Mahajan, Aman; Shivkumar, Kalyanam; Kim, Kang; O’Donnell, Matthew; Nikoozadeh, Amin; Oralkan, Omer; Khuri-Yakub, Pierre T.; Sahn, David J.

    2015-01-01

    A family of 3 multifunctional intracardiac imaging and electrophysiology (EP) mapping catheters has been in development to help guide diagnostic and therapeutic intracardiac EP procedures. The catheter tip on the first device includes a 7.5 MHz, 64-element, side-looking phased array for high resolution sector scanning. The second device is a forward-looking catheter with a 24-element 14 MHz phased array. Both of these catheters operate on a commercial imaging system with standard software. Multiple EP mapping sensors were mounted as ring electrodes near the arrays for electrocardiographic synchronization of ultrasound images and used for unique integration with EP mapping technologies. To help establish the catheters’ ability for integration with EP interventional procedures, tests were performed in vivo in a porcine animal model to demonstrate both useful intracardiac echocardiographic (ICE) visualization and simultaneous 3-D positional information using integrated electroanatomical mapping techniques. The catheters also performed well in high frame rate imaging, color flow imaging, and strain rate imaging of atrial and ventricular structures. The companion paper of this work discusses the catheter design of the side-looking catheter with special attention to acoustic lens design. The third device in development is a 10 MHz forward-looking ring array that is to be mounted at the distal tip of a 9F catheter to permit use of the available catheter lumen for adjunctive therapy tools. PMID:18986948

  18. Audiological and electrophysiological assessment of professional pop/rock musicians.

    PubMed

    Samelli, Alessandra G; Matas, Carla G; Carvallo, Renata M M; Gomes, Raquel F; de Beija, Carolina S; Magliaro, Fernanda C L; Rabelo, Camila M

    2012-01-01

    In the present study, we evaluated peripheral and central auditory pathways in professional musicians (with and without hearing loss) compared to non-musicians. The goal was to verify if music exposure could affect auditory pathways as a whole. This is a prospective study that compared the results obtained between three groups (musicians with and without hearing loss and non-musicians). Thirty-two male individuals participated and they were assessed by: Immittance measurements, pure-tone air conduction thresholds at all frequencies from 0.25 to 20 kHz, Transient Evoked Otoacoustic Emissions, Auditory Brainstem Response (ABR), and Cognitive Potential. The musicians showed worse hearing thresholds in both conventional and high frequency audiometry when compared to the non-musicians; the mean amplitude of Transient Evoked Otoacoustic Emissions was smaller in the musicians group, but the mean latencies of Auditory Brainstem Response and Cognitive Potential were diminished in the musicians when compared to the non-musicians. Our findings suggest that the population of musicians is at risk for developing music-induced hearing loss. However, the electrophysiological evaluation showed that latency waves of ABR and P300 were diminished in musicians, which may suggest that the auditory training to which these musicians are exposed acts as a facilitator of the acoustic signal transmission to the cortex.

  19. Electrophysiological measurement of interest during walking in a simulated environment.

    PubMed

    Takeda, Yuji; Okuma, Takashi; Kimura, Motohiro; Kurata, Takeshi; Takenaka, Takeshi; Iwaki, Sunao

    2014-09-01

    A reliable neuroscientific technique for objectively estimating the degree of interest in a real environment is currently required in the research fields of neuroergonomics and neuroeconomics. Toward the development of such a technique, the present study explored electrophysiological measures that reflect an observer's interest in a nearly-real visual environment. Participants were asked to walk through a simulated shopping mall and the attractiveness of the shopping mall was manipulated by opening and closing the shutters of stores. During the walking task, participants were exposed to task-irrelevant auditory probes (two-stimulus oddball sequence). The results showed a smaller P2/early P3a component of task-irrelevant auditory event-related potentials and a larger lambda response of eye-fixation-related potentials in an interesting environment (i.e., open-shutter condition) than in a boring environment (i.e., closed-shutter condition); these findings can be reasonably explained by supposing that participants allocated more attentional resources to visual information in an interesting environment than in a boring environment, and thus residual attentional resources that could be allocated to task-irrelevant auditory probes were reduced. The P2/early P3a component and the lambda response may be useful measures of interest in a real visual environment.

  20. An unpleasant emotional state reduces working memory capacity: electrophysiological evidence.

    PubMed

    Figueira, Jessica S B; Oliveira, Leticia; Pereira, Mirtes G; Pacheco, Luiza B; Lobo, Isabela; Motta-Ribeiro, Gabriel C; David, Isabel A

    2017-04-11

    Emotional states can guide the actions and decisions we make in our everyday life through their influence on cognitive processes such as working memory (WM). We investigated the long-lasting interference that an unpleasant emotional state had on goal-relevant WM representations from an electrophysiological perspective. Participants performed a change detection task that was preceded by the presentation of unpleasant or neutral task-irrelevant pictures in a blocked fashion. We focused on the contralateral delay activity (CDA), an event-related potential that is sensitive to the number of task-relevant items stored in WM. We found that the asymptotic limit for the CDA amplitude was lower during the unpleasant emotional state than during the neutral one; that is, an emotional state was capable of reducing how many task-relevant items the participants could hold in WM. Furthermore, both the individuals who experienced more intrusive thoughts and those who were dispositionally anxious were more susceptible to the influence of the emotional state. We provide evidence that an unpleasant emotional state diminished visual WM for task-relevant items, particularly in susceptible individuals. These results open new avenues to uncover the emotional-cognitive processing that underlies maladaptive WM representations and the role of such processing in the development of mental illness.

  1. [Electrophysiological properties of inhibitory neurones in cultured dissociated hippocampal cells].

    PubMed

    Moskaliuk, A O; Kolodin, Iu O; Kravchenko, M O; Fedulova, S A; Veselovs'kyĭ, M S

    2004-01-01

    Electrophysiological properties of inhibitory (GABAergic) neurones were studied in dissociated hippocampal culture using simultaneous whole cell recordings from pairs of monosynaptically coupled neurons. Reliable identification of GABAergic neuron was performed by presence of monosynaptic inhibitory currents at postsynaptic cell in response to action potentials at stimulated cell. It was shown that GABAergic neurons in hippocampal culture are divided in two groups by their firing characteristics: first type generates action potentials at high frequency in response to injection of current (duration 0.5 s)--fast-spiking neurons (FS), cells from second type has no ability for high-frequency action potential generation--regular spiking neurons (RS). These two groups were distinguished by kinetic characteristics of action potentials, adaptation characteristics during continuous generation of action potentials and inhibitory effect making on postsynaptic cell. Application of potassium channel blocker 4-AP to somas of FS neurons in concentration, which selectively inhibits Kv3 potassium channels evoked reversible changes in kinetic of action potentials, frequency and adaptation characteristics during continuous generation of action potentials. It was concluded that there is hight level of expression of Kv3 potassium channels in the first group of neurons.

  2. Canonical Wnt Signaling Regulates Atrioventricular Junction Programming and Electrophysiological Properties

    PubMed Central

    Gillers, Benjamin S; Chiplunkar, Aditi; Aly, Haytham; Valenta, Tomas; Basler, Konrad; Christoffels, Vincent M.; Efimov, Igor R; Boukens, Bastiaan J; Rentschler, Stacey

    2014-01-01

    Rationale Proper patterning of the atrioventricular canal (AVC) is essential for delay of electrical impulses between atria and ventricles, and defects in AVC maturation can result in congenital heart disease. Objective To determine the role of canonical Wnt signaling in the myocardium during AVC development. Methods and Results We utilized a novel allele of β-catenin that preserves β-catenin’s cell adhesive functions but disrupts canonical Wnt signaling, allowing us to probe the effects of Wnt loss of function independently. We show that loss of canonical Wnt signaling in the myocardium results in tricuspid atresia with hypoplastic right ventricle associated with loss of AVC myocardium. In contrast, ectopic activation of Wnt signaling was sufficient to induce formation of ectopic AV junction-like tissue as assessed by morphology, gene expression, and electrophysiologic criteria. Aberrant AVC development can lead to ventricular preexcitation, a characteristic feature of Wolff-Parkinson-White syndrome. We demonstrate that postnatal activation of Notch signaling downregulates canonical Wnt targets within the AV junction. Stabilization of β-catenin protein levels can rescue Notch-mediated ventricular preexcitation and dysregulated ion channel gene expression. Conclusions Our data demonstrate that myocardial canonical Wnt signaling is an important regulator of AVC maturation and electrical programming upstream of Tbx3. Our data further suggests that ventricular preexcitation may require both morphologic patterning defects, as well as myocardial lineage reprogramming, to allow robust conduction across accessory pathway tissue. PMID:25599332

  3. [Electrophysiological characteristics of the isolated muscle spindle in rats].

    PubMed

    Zhao, Xue-Hong; Fan, Xiao-Li; Song, Xin-Ai; Shi, Lei

    2011-06-25

    The aim of this study was to observe the electrophysiological characteristics of the isolated rat muscle spindle. The muscle spindle was isolated from rat soleus and the afferent discharge of the isolated muscle spindle was recorded by air-gap technique. In the basic physiological salt solution, the spontaneous impulses of muscle spindle were at a lower level with irregular intervals. The mean frequency of afferents was (51.78 ± 25.63) impulses/1 000 s (n = 13). The muscle spindle afferents were significantly increased and maintained over time by the addition of certain amino acids during the observation. The number of the action potential recorded per 1 000 s was 200-1 000 [mean: (687.62 ± 312.56) impulses/1 000 s, n = 17]. In addition to the typical propagated action potential, a large number of abortive spikes were observed. The results indicate that the activities of isolated muscle spindles in rats can be well maintained by the addition of certain amino acids. The results initially establish and provide the possibility for further research conducted in isolated rat muscle spindles.

  4. Structural defects lead to dynamic entrapment in cardiac electrophysiology.

    PubMed

    Bates, Oliver R J; Suki, Bela; Spector, Peter S; Bates, Jason H T

    2015-01-01

    Biological networks are typically comprised of many parts whose interactions are governed by nonlinear dynamics. This potentially imbues them with the ability to support multiple attractors, and therefore to exhibit correspondingly distinct patterns of behavior. In particular, multiple attractors have been demonstrated for the electrical activity of the diseased heart in situations where cardioversion is able to convert a reentrant arrhythmia to a stable normal rhythm. Healthy hearts, however, are typically resilient to abnormal rhythms. This raises the question as to how a healthy cardiac cell network must be altered so that it can support multiple distinct behaviors. Here we demonstrate how anatomic defects can give rise to multi-stability in the heart as a function of the electrophysiological properties of the cardiac tissue and the timing of activation of ectopic foci. This leads to a form of hysteretic behavior, which we call dynamic entrapment, whereby the heart can become trapped in aberrant attractor as a result of a transient change in tissue properties. We show that this can lead to a highly inconsistent relationship between clinical symptoms and underlying pathophysiology, which raises the possibility that dynamic entrapment may underlie other forms of chronic idiopathic illness.

  5. A neural mass model of spectral responses in electrophysiology

    PubMed Central

    Moran, R.J.; Kiebel, S.J.; Stephan, K.E.; Reilly, R.B.; Daunizeau, J.; Friston, K.J.

    2007-01-01

    We present a neural mass model of steady-state membrane potentials measured with local field potentials or electroencephalography in the frequency domain. This model is an extended version of previous dynamic causal models for investigating event-related potentials in the time-domain. In this paper, we augment the previous formulation with parameters that mediate spike-rate adaptation and recurrent intrinsic inhibitory connections. We then use linear systems analysis to show how the model's spectral response changes with its neurophysiological parameters. We demonstrate that much of the interesting behaviour depends on the non-linearity which couples mean membrane potential to mean spiking rate. This non-linearity is analogous, at the population level, to the firing rate–input curves often used to characterize single-cell responses. This function depends on the model's gain and adaptation currents which, neurobiologically, are influenced by the activity of modulatory neurotransmitters. The key contribution of this paper is to show how neuromodulatory effects can be modelled by adding adaptation currents to a simple phenomenological model of EEG. Critically, we show that these effects are expressed in a systematic way in the spectral density of EEG recordings. Inversion of the model, given such non-invasive recordings, should allow one to quantify pharmacologically induced changes in adaptation currents. In short, this work establishes a forward or generative model of electrophysiological recordings for psychopharmacological studies. PMID:17632015

  6. First steps towards initial registration for electrophysiology procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Bourier, Felix; Yatziv, Liron; Koch, Martin; Hornegger, Joachim; Strobel, Norbert; Kurzidim, Klaus

    2011-03-01

    Atrial fibrillation is the most common heart arrhythmia and a leading cause of stroke. The treatment option of choice is radio-frequency catheter ablation, which is performed in electrophysiology labs using C-Arm X-ray systems for navigation and guidance. The goal is to electrically isolate the pulmonary vein-left atrial junction thereby rendering myocardial fibers responsible for induction and maintenance of AF inactive. The use of overlay images for fluoroscopic guidance may improve the quality of the ablation procedure, and can reduce procedure time. Overlay images, acquired using CT, MRI, or C-arm CT, can add soft-tissue information, otherwise not visible under X-ray. MRI can be used to image a wide variety of anatomical details without ionizing radiation. In this paper, we present a method to register a 3-D MRI volume to 2-D biplane X-ray images using the coronary sinus. Current approaches require registration of the overlay images to the fluoroscopic images to be performed after the trans-septal puncture, when contast agent can be administered. We present a new approach for registration to align overlay images before the trans-septal puncture. To this end, we manually extract the coronary sinus from pre-operative MRI and register it to a multi-electorde catheter placed in the coronary sinus.

  7. Electrophysiologic features of fetal ventricular aneurysms and diverticula

    PubMed Central

    PETERS, CARLI; WACKER-GUSSMANN, ANNETTE; STRASBURGER, JANETTE F; CUNEO, BETTINA F; GOTTEINER, NINA; GULECYUZ, MEHEMET; WAKAI, RONALD T

    2014-01-01

    Objective Congenital ventricular wall defects are very rare and include congenital ventricular aneurysms (CVAs) and diverticula (CVDs). Method We report a series of five fetuses: three with CVAs and two with CVDs referred due to fetal arrhythmia. In addition to routine fetal echocardiography, fetal magnetocardiography (fMCG) was used. The literature in CVA and CVD is reviewed. Results Incessant premature ventricular contractions (PVC), mainly bigeminy and trigeminy were found in three fetuses with CVAs and in one with CVD, who also had ventricular couplets. The other fetus with CVD, referred because of PVCs, had only sinus tachycardia. ST elevation was noted in two. Fetal movement had a variable impact on PVC’s. Postnatal evaluation demonstrated two persistent left ventricular aneurysms and one persistent right CVD; one CVD resolved at 35 weeks gestation. Two neonates had incessant PVCs. Both arrhythmias resolved spontaneously while being treated with propranolol. Conclusion FMCG is complementary to echocardiographic imaging. In fetuses with left ventricular wall defects, additional electrophysiological diagnosis can be made by fMCG, including the complexity of ventricular ectopy, arrhythmic response to fetal movement, presence of ST-T wave abnormalities, and atrial amplitude increases. Prenatal risk factor assessment using fMCG can additionally support post-natal treatment and follow-up. PMID:25284224

  8. Uniform qualitative electrophysiological changes in postoperative rest tremor.

    PubMed

    Kovacs, Norbert; Balas, Istvan; Illes, Zsolt; Kellenyi, Lorant; Doczi, Tamas P; Czopf, Jozsef; Poto, Laszlo; Nagy, Ferenc

    2006-03-01

    Ablation and deep brain stimulation (DBS) can treat pharmacologically uncontrollable tremor. Here, we compared the postoperative electrophysiological changes in resting hand tremor after 32 ablations and 12 DBS implantations in patients with severe tremor-dominant idiopathic Parkinson's disease (PD) and essential tremor (ET). Short- and long-term accelerometric data were acquired after surgery and were compared to the preoperative tremor. After effective surgical treatments, significant rest tremor reduction and increase in both frequency and approximate entropy (ApEn) were detected in all PD cases, irrespective of the type and target of intervention. However, the long-term effect of DBS implantation on tremor reduction was significantly better compared to that after ablative treatments. In cases of thalamotomy, the postoperative increase in frequency and ApEn was significantly larger in essential tremor compared to PD, suggesting that the etiology of tremor may influence the size of the similar changes. However, cases where clinical tremor re-emerged 6 to 12 months after the surgery, no change in frequency and ApEn was detected on the second postoperative day, despite an initial tremor reduction and clinical improvement similar to the effective operations. Our results suggest that uniform postoperative changes in rest tremor and the increase in frequency and ApEn could be due to attenuation of pathological oscillators and might be immediate indicators of the effectiveness of neurosurgical treatments relieving tremor.

  9. [Clinical, immunological, and electrophysiological matching in Raynaud's syndrome].

    PubMed

    Gerasimova, M M; Cherdyntsev, M G

    2005-01-01

    Detailed description of Raynaud's syndrome (RS) dates back to the 19th century; nevertheless, this problem is still topical because of high prevalence of the syndrome (4 to 5% of population), and the fact that different specialists have to deal with it. The authors of the article studied clinical, immunological, and electrophysiological peculiarities of 103 patients with RS, both primary and secondary one. The examination included measurement of the level of antibodies to nerve growth factor (NGF) and myeline basic protein (MBP) and electroneuromyography. All the subjects displayed significant elevation of serum titer of MBP and NGF antibodies, and lowered peripheral nerve impulse conduction velocity (ICV). There was a direct correlation between antibody titer and the severity of the disease, and inverse correlation between ICV of sensory nervous fibers and the severity of the disease. Thus, RS is almost always associated with peripheral sensory fiber pathology, whose clinical manifestation consists in demyelinating polyneuropathy of autoimmune origin; the more prominent demyelinization, the higher the degree of disease severity.

  10. Electrophysiological and functional connectivity of the human supplementary motor area.

    PubMed

    Narayana, Shalini; Laird, Angela R; Tandon, Nitin; Franklin, Crystal; Lancaster, Jack L; Fox, Peter T

    2012-08-01

    Neuro-imaging methods for detecting functional and structural inter-regional connectivity are in a rapid phase of development. While reports of regional connectivity patterns based on individual methods are becoming common, studies comparing the results of two or more connectivity-mapping methods remain rare. In this study, we applied transcranial magnetic stimulation during PET imaging (TMS/PET), a stimulation-based method, and meta-analytic connectivity modeling (MACM), a task-based method to map the connectivity patterns of the supplementary motor area (SMA). Further, we drew upon the behavioral domain meta-data of the BrainMap® database to characterize the behavioral domain specificity of two maps. Both MACM and TMS/PET detected multi-synaptic connectivity patterns, with the MACM-detected connections being more extensive. Both MACM and TMS/PET detected connections belonging to multiple behavioral domains, including action, cognition and perception. Finally, we show that the two connectivity-mapping methods are complementary in that, the MACM informed on the functional nature of SMA connections, while TMS/PET identified brain areas electrophysiologically connected with the SMA. Thus, we demonstrate that integrating multimodal database and imaging techniques can derive comprehensive connectivity maps of brain areas.

  11. The contribution of electrophysiology to functional connectivity mapping

    PubMed Central

    Schölvinck, Marieke L; Leopold, David A; Brookes, Matthew J; Khader, Patrick H

    2014-01-01

    A powerful way to probe brain function is to assess the relationship between simultaneous changes in activity across different parts of the brain. In recent years, the temporal activity correlation between brain areas has frequently been taken as a measure of their functional connections. Evaluating ‘functional connectivity’ in this way is particularly popular in the fMRI community, but has also drawn interest among electrophysiologists. Like hemodynamic fluctuations observed with fMRI, electrophysiological signals display significant temporal fluctuations, even in the absence of a stimulus. These neural fluctuations exhibit correlational structure over a wide range of spatial and temporal scales. Initial evidence suggests that certain aspects of this correlational structure bear a high correspondence to so-called functional networks defined using fMRI. The growing family of methods to study activity covariation, combined with the diverse neural mechanisms that contribute to the spontaneous fluctuations, have somewhat blurred the operational concept of functional connectivity. What is clear is that spontaneous activity is a conspicuous, energy-consuming feature of the brain. Given its prominence and its practical applications for the functional connectivity mapping of brain networks, it is of increasing importance that we understand its neural origins as well as its contribution to normal brain function. PMID:23587686

  12. Logo Effects on Brand Extension Evaluations from the Electrophysiological Perspective.

    PubMed

    Shang, Qian; Pei, Guanxiong; Dai, Shenyi; Wang, Xiaoyi

    2017-01-01

    Brand extension typically has two strategies: brand name extension (BN) and brand logo extension (BL). The current study explored which strategy (BN or BL) better enhanced the success of dissimilar brand extension and product promotion in enterprises. Event-related potentials (ERPs) were used to investigate electrophysiological processes when subjects evaluated their acceptance of the brand extension using a combined picture of S1 and S2. S1 was a famous brand presented by two identity signs (brand name and brand logo). S2 was a picture of an extension product that belonged to a dissimilar product category than S1. The behavior data showed that BL was more acceptable than BN in the dissimilar brand extension. The neurophysiology process was reflected by a less negative N2 component and a larger P300 component in the BL than in the BN. We suggested that N2 reflected a whole conflict between the brand-product combination and the long-term memory and that P300 could be regarded as the reflection of the categorization process in the working memory.

  13. Electrophysiological Correlates of Long-Term Soto Zen Meditation

    PubMed Central

    Pasquini, Henrique Adam; Tanaka, Guaraci Ken; Basile, Luis Fernando Hindi; Velasques, Bruna; Lozano, Mirna Delposo

    2015-01-01

    This study aimed to verify the electrophysiological correlates of the changes in long-term regular meditators. We use modern techniques of high-resolution electroencephalography applied to slow potentials, power spectra, and potencies related to the events. To obtain encephalographic records, we use an assembly of 128 channels in 31 subjects (17 Soto Zen Buddhist meditators). The motivation of this study was to determine whether the induced beta power would present an increase in meditators as well as a decrease in induced theta/beta ratio in absolute and relative values. However, opposite to what we expected, no significant change was found in the beta frequency. In contrast, the main findings of the study were correlations between the frequency of weekly meditation practice and the increased theta induced relative power, increase of induced power ratio (ratio theta/beta), and increase of the ratio of induced relative powers (theta/beta ratio) during our task that featured an “adapted meditation,” suggesting that the meditative state of “mindfulness” is much more related to the permittivity of “distractions” by the meditators, with a deliberate reduction of attention. PMID:25632397

  14. Electrophysiological Properties of Embryonic Stem Cell-Derived Neurons

    PubMed Central

    Risner-Janiczek, Jessica R.; Ungless, Mark A.; Li, Meng

    2011-01-01

    In vitro generation of functional neurons from embryonic stem (ES) cells and induced pluripotent stem cells offers exciting opportunities for dissecting gene function, disease modelling, and therapeutic drug screening. To realize the potential of stem cells in these biomedical applications, a complete understanding of the cell models of interest is required. While rapid advances have been made in developing the technologies for directed induction of defined neuronal subtypes, most published works focus on the molecular characterization of the derived neural cultures. To characterize the functional properties of these neural cultures, we utilized an ES cell model that gave rise to neurons expressing the green fluorescent protein (GFP) and conducted targeted whole-cell electrophysiological recordings from ES cell-derived neurons. Current-clamp recordings revealed that most neurons could fire single overshooting action potentials; in some cases multiple action potentials could be evoked by depolarization, or occurred spontaneously. Voltage-clamp recordings revealed that neurons exhibited neuronal-like currents, including an outward current typical of a delayed rectifier potassium conductance and a fast-activating, fast-inactivating inward current, typical of a sodium conductance. Taken together, these results indicate that ES cell-derived GFP+ neurons in culture display functional neuronal properties even at early stages of differentiation. PMID:21887381

  15. Multiplexed, High Density Electrophysiology with Nanofabricated Neural Probes

    PubMed Central

    Du, Jiangang; Blanche, Timothy J.; Harrison, Reid R.; Lester, Henry A.; Masmanidis, Sotiris C.

    2011-01-01

    Extracellular electrode arrays can reveal the neuronal network correlates of behavior with single-cell, single-spike, and sub-millisecond resolution. However, implantable electrodes are inherently invasive, and efforts to scale up the number and density of recording sites must compromise on device size in order to connect the electrodes. Here, we report on silicon-based neural probes employing nanofabricated, high-density electrical leads. Furthermore, we address the challenge of reading out multichannel data with an application-specific integrated circuit (ASIC) performing signal amplification, band-pass filtering, and multiplexing functions. We demonstrate high spatial resolution extracellular measurements with a fully integrated, low noise 64-channel system weighing just 330 mg. The on-chip multiplexers make possible recordings with substantially fewer external wires than the number of input channels. By combining nanofabricated probes with ASICs we have implemented a system for performing large-scale, high-density electrophysiology in small, freely behaving animals that is both minimally invasive and highly scalable. PMID:22022568

  16. Electrophysiological properties of cultured hippocampal neurons from Wistar Audiogenic Rats.

    PubMed

    Mesquita, Fernando; Aguiar, José F; Oliveira, José A; Garcia-Cairasco, Norberto; Varanda, Wamberto A

    2005-03-15

    The main goal of this work was to analyze the electrophysiological properties of cultured hippocampal neurons from a particular epileptic rat strain, called Wistar Audiogenic Rats (WAR). The whole-cell patch-clamp technique was used to record both active and passive membrane responses in an attempt to detect alterations in their characteristics in relation to controls from Wistar rats. Neurons from WARs show a significant reduction in the magnitude of the inhibitory GABAergic currents ( approximately 45%), in spite of maintaining a normal level of the excitatory glutamatergic currents. In addition, the magnitude of potassium currents, measured at +80 mV, is reduced by about 30% in comparison to controls. Surprisingly, we also found important changes in the passive cellular properties in WAR neurons such as membrane potential (-50.0 mV in WARs and -63.1 mV in controls) and input resistance (647 MOmega in WARs and 408 MOmega in controls). The changes described here, could be the basis of the neurophysiological and behavioral alterations present in these hyperexcitable animals, contributing to a better understanding of epileptogenesis in this particular animal model.

  17. Simulating Cardiac Electrophysiology Using Unstructured All-Hexahedra Spectral Elements

    PubMed Central

    Cuccuru, Gianmauro; Fotia, Giorgio; Maggio, Fabio; Southern, James

    2015-01-01

    We discuss the application of the spectral element method to the monodomain and bidomain equations describing propagation of cardiac action potential. Models of cardiac electrophysiology consist of a system of partial differential equations coupled with a system of ordinary differential equations representing cell membrane dynamics. The solution of these equations requires solving multiple length scales due to the ratio of advection to diffusion that varies among the different equations. High order approximation of spectral elements provides greater flexibility in resolving multiple length scales. Furthermore, spectral elements are extremely efficient to model propagation phenomena on complex shapes using fewer degrees of freedom than its finite element equivalent (for the same level of accuracy). We illustrate a fully unstructured all-hexahedra approach implementation of the method and we apply it to the solution of full 3D monodomain and bidomain test cases. We discuss some key elements of the proposed approach on some selected benchmarks and on an anatomically based whole heart human computational model. PMID:26583112

  18. Logo Effects on Brand Extension Evaluations from the Electrophysiological Perspective

    PubMed Central

    Shang, Qian; Pei, Guanxiong; Dai, Shenyi; Wang, Xiaoyi

    2017-01-01

    Brand extension typically has two strategies: brand name extension (BN) and brand logo extension (BL). The current study explored which strategy (BN or BL) better enhanced the success of dissimilar brand extension and product promotion in enterprises. Event-related potentials (ERPs) were used to investigate electrophysiological processes when subjects evaluated their acceptance of the brand extension using a combined picture of S1 and S2. S1 was a famous brand presented by two identity signs (brand name and brand logo). S2 was a picture of an extension product that belonged to a dissimilar product category than S1. The behavior data showed that BL was more acceptable than BN in the dissimilar brand extension. The neurophysiology process was reflected by a less negative N2 component and a larger P300 component in the BL than in the BN. We suggested that N2 reflected a whole conflict between the brand-product combination and the long-term memory and that P300 could be regarded as the reflection of the categorization process in the working memory. PMID:28337121

  19. The electrophysiological underpinnings of processing gender stereotypes in language.

    PubMed

    Siyanova-Chanturia, Anna; Pesciarelli, Francesca; Cacciari, Cristina

    2012-01-01

    Despite the widely documented influence of gender stereotypes on social behaviour, little is known about the electrophysiological substrates engaged in the processing of such information when conveyed by language. Using event-related brain potentials (ERPs), we examined the brain response to third-person pronouns (lei "she" and lui "he") that were implicitly primed by definitional (passeggera(FEM) "passenger", pensionato(MASC) "pensioner"), or stereotypical antecedents (insegnante "teacher", conducente "driver"). An N400-like effect on the pronoun emerged when it was preceded by a definitionally incongruent prime (passeggera(FEM)--lui; pensionato(MASC)--lei), and a stereotypically incongruent prime for masculine pronouns only (insegnante--lui). In addition, a P300-like effect was found when the pronoun was preceded by definitionally incongruent primes. However, this effect was observed for female, but not male participants. Overall, these results provide further evidence for on-line effects of stereotypical gender in language comprehension. Importantly, our results also suggest a gender stereotype asymmetry in that male and female stereotypes affected the processing of pronouns differently.

  20. Structural Defects Lead to Dynamic Entrapment in Cardiac Electrophysiology

    PubMed Central

    Bates, Oliver R. J.; Suki, Bela; Spector, Peter S.; Bates, Jason H. T.

    2015-01-01

    Biological networks are typically comprised of many parts whose interactions are governed by nonlinear dynamics. This potentially imbues them with the ability to support multiple attractors, and therefore to exhibit correspondingly distinct patterns of behavior. In particular, multiple attractors have been demonstrated for the electrical activity of the diseased heart in situations where cardioversion is able to convert a reentrant arrhythmia to a stable normal rhythm. Healthy hearts, however, are typically resilient to abnormal rhythms. This raises the question as to how a healthy cardiac cell network must be altered so that it can support multiple distinct behaviors. Here we demonstrate how anatomic defects can give rise to multi-stability in the heart as a function of the electrophysiological properties of the cardiac tissue and the timing of activation of ectopic foci. This leads to a form of hysteretic behavior, which we call dynamic entrapment, whereby the heart can become trapped in aberrant attractor as a result of a transient change in tissue properties. We show that this can lead to a highly inconsistent relationship between clinical symptoms and underlying pathophysiology, which raises the possibility that dynamic entrapment may underlie other forms of chronic idiopathic illness. PMID:25756656

  1. Spectrally resolved fast transient brain states in electrophysiological data

    PubMed Central

    Vidaurre, Diego; Quinn, Andrew J.; Baker, Adam P.; Dupret, David; Tejero-Cantero, Alvaro; Woolrich, Mark W.

    2016-01-01

    The brain is capable of producing coordinated fast changing neural dynamics across multiple brain regions in order to adapt to rapidly changing environments. However, it is non-trivial to identify multiregion dynamics at fast sub-second time-scales in electrophysiological data. We propose a method that, with no knowledge of any task timings, can simultaneously identify and describe fast transient multiregion dynamics in terms of their temporal, spectral and spatial properties. The approach models brain activity using a discrete set of sequential states, with each state distinguished by its own multiregion spectral properties. This can identify potentially very short-lived visits to a brain state, at the same time as inferring the state's properties, by pooling over many repeated visits to that state. We show how this can be used to compute state-specific measures such as power spectra and coherence. We demonstrate that this can be used to identify short-lived transient brain states with distinct power and functional connectivity (e.g., coherence) properties in an MEG data set collected during a volitional motor task. PMID:26631815

  2. Electrophysiological correlates of long-term Soto Zen meditation.

    PubMed

    Pasquini, Henrique Adam; Tanaka, Guaraci Ken; Basile, Luis Fernando Hindi; Velasques, Bruna; Lozano, Mirna Delposo; Ribeiro, Pedro

    2015-01-01

    This study aimed to verify the electrophysiological correlates of the changes in long-term regular meditators. We use modern techniques of high-resolution electroencephalography applied to slow potentials, power spectra, and potencies related to the events. To obtain encephalographic records, we use an assembly of 128 channels in 31 subjects (17 Soto Zen Buddhist meditators). The motivation of this study was to determine whether the induced beta power would present an increase in meditators as well as a decrease in induced theta/beta ratio in absolute and relative values. However, opposite to what we expected, no significant change was found in the beta frequency. In contrast, the main findings of the study were correlations between the frequency of weekly meditation practice and the increased theta induced relative power, increase of induced power ratio (ratio theta/beta), and increase of the ratio of induced relative powers (theta/beta ratio) during our task that featured an "adapted meditation," suggesting that the meditative state of "mindfulness" is much more related to the permittivity of "distractions" by the meditators, with a deliberate reduction of attention.

  3. Drug-induced proarrhythmia: risk factors and electrophysiological mechanisms.

    PubMed

    Frommeyer, Gerrit; Eckardt, Lars

    2016-01-01

    Drug-induced ventricular tachyarrhythmias can be caused by cardiovascular drugs, noncardiovascular drugs, and even nonprescription agents. They can result in arrhythmic emergencies and sudden cardiac death. If a new arrhythmia or aggravation of an existing arrhythmia develops during therapy with a drug at a concentration usually considered not to be toxic, the situation can be defined as proarrhythmia. Various cardiovascular and noncardiovascular drugs can increase the occurrence of polymorphic ventricular tachycardia of the 'torsade de pointes' type. Antiarrhythmic drugs, antimicrobial agents, and antipsychotic and antidepressant drugs are the most important groups. Age, female sex, and structural heart disease are important risk factors for the occurrence of torsade de pointes. Genetic predisposition and individual pharmacodynamic and pharmacokinetic sensitivity also have important roles in the generation of arrhythmias. An increase in spatial or temporal dispersion of repolarization and a triangular action-potential configuration have been identified as crucial predictors of proarrhythmia in experimental models. These studies emphasized that sole consideration of the QT interval is not sufficient to assess the proarrhythmic risk. In this Review, we focus on important triggers of proarrhythmia and the underlying electrophysiological mechanisms that can enhance or prevent the development of torsade de pointes.

  4. Intraoperative monitoring by imaging and electrophysiological techniques during giant intracranial aneurysm surgery.

    PubMed

    Durand, A; Penchet, G; Thines, L

    2016-02-01

    Difficulties in giant intracranial aneurysm surgery are the consequence of aneurysmal wall histology and the complex angioarchitecture of the vascular tree. In order to reduce complications and risks of those procedures, various imaging and electrophysiological techniques can be implemented perioperatively. The authors review the principles, goals and main results in this context of micro-Doppler and flowmeter techniques, near-infrared spectroscopy, operative microscope-integrated indocyanine green video-angiography, neuro-endoscopy, selective intraoperative angiography and electrophysiological monitoring.

  5. Estimation of the acute inhalation hazards of chemicals based on route-to-route and local endpoint extrapolation: experience from bulk maritime transport.

    PubMed

    Höfer, Thomas; James, Derek; Syversen, Tore; Bowmer, Tim

    2011-12-01

    Data on acute lethal inhalation toxicity from animal studies are commonly required for assessing the hazards to human health of volatile, gaseous and dusty chemicals or their mixtures. The International Maritime Organisation (IMO) made the provision of acute inhalation toxicity data a mandatory requirement for the carriage of bulk liquid chemicals transported by sea in tank ships, thereby creating the need for inhalation data on many hundreds of chemicals in bulk maritime transport. Taking note of previously published proposals for estimating acute inhalation toxicity hazards for chemicals, and the paucity of measured experimental data, an extrapolation method has been developed by the Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) to partly fulfil this need. This method should be seen as a pragmatic approach to the challenge of missing measured experimental test data, with the added benefit of reducing tests in experimental animals. The method is based on a route-to-route (i.e. between-route) extrapolation of information on acute oral and/or dermal toxicity, in combination with data on the potential for irritation and/or corrosion to skin and eyes. The validation of this method was based on the individual evaluation of inhalation toxicity studies for 330 chemicals, including mixtures and many important chemical groups, for which the IMO holds public and industry-confidential data. The authors contend that this extrapolation method offers a reliable basis for hazard evaluation in the context of bulk maritime transport, and the 'GESAMP inhalation toxicity extrapolation method' has become part of the IMO regulatory system for the carriage of bulk liquids (i.e. noxious liquid substances) on board tank ships.

  6. Utility of CT perfusion scanning in patient selection for acute stroke intervention: experience at University at Buffalo Neurosurgery-Millard Fillmore Gates Circle Hospital.

    PubMed

    Kan, Peter T; Snyder, Kenneth V; Yashar, Parham; Siddiqui, Adnan H; Hopkins, L Nelson; Levy, Elad I

    2011-06-01

    Computed tomography perfusion scanning generates physiological flow parameters of the brain parenchyma, allowing differentiation of ischemic penumbra and core infarct. Perfusion maps, along with the National Institutes of Health Stroke Scale score, are used as the bases for endovascular stroke intervention at the authors' institute, regardless of the time interval from stroke onset. With case examples, the authors illustrate their perfusion-based imaging guidelines in patient selection for endovascular treatment in the setting of acute stroke.

  7. [Acute quadriplegia after diabetic ketoacidosis].

    PubMed

    Mihalik, Zoltán; Arányi, Zsuzsanna; Siska, Eva; Nyulasi, Tibor; Pénzes, István

    2003-11-02

    A 36-year-old female was admitted to the intensive care unit after resuscitation diagnosed with diabetic ketoacidotic coma, which was the first manifestation of her diabetes mellitus. It may have been provoked by pulmonary or gastrointestinal coinfection. Five days following admission the patient regained consciousness and homeostasis returned to normal. One week after the stabilization of her cardiopulmonary state, weaning from the respirator turned out to be unsuccessful: flaccid tetraparesis developed with rapid muscle atrophy and absence of deep tendon reflexes. The sensory system and cranial nerves remained intact. Electrophysiological studies and muscle biopsy showed serious acute illness myopathy with mild demyelination owing probably to the latent diabetes. The course of acute quadriplegia was fluctuating and correlated mainly with the activity of the systemic inflammatory response syndrome mechanisms. Myopathy might have been aggravated by using high-dose glucocorticoid therapy. The patient's general condition improved quickly as a result of full recovery from sepsis, discontinuation of glucocorticoids and normoglicaemia maintained by subcutan insulin substitution. Eight months after admission almost full neuromuscular restitution was achieved showing the reversibility of this grave illness.

  8. [Acute pancreatitis].

    PubMed

    Hecker, M; Mayer, K; Askevold, I; Collet, P; Weigand, M A; Krombach, G A; Padberg, W; Hecker, A

    2014-03-01

    Acute pancreatitis is a potentially fatal disease with individually differing expression of systemic involvement. For this reason early diagnosis with subsequent risk stratification is essential in the clinical management of this frequent gastroenterological disorder. Severe forms of acute pancreatitis occur in approximately 20 % of cases often requiring intensive care monitoring and interdisciplinary therapeutic approaches. In the acute phase adequate fluid replacement and sufficient analgesic therapy is of major therapeutic importance. Concerning the administration of antibiotics and the nutritional support of patients with acute pancreatitis a change in paradigms could be observed in recent years. Furthermore, endoscopic, radiological or surgical interventions can be necessary depending on the severity of the disease and potential complications.

  9. Bronchitis - acute

    MedlinePlus

    ... to breathe. Other symptoms of bronchitis are a cough and coughing up mucus. Acute means the symptoms ... diagnosed with chronic bronchitis, you must have a cough with mucus on most days for at least ...

  10. Acute Bronchitis

    MedlinePlus

    ... bronchitis? Acute bronchitis is inflammation of your bronchial tree. The bronchial tree consists of tubes that carry air into your ... weeks or months. This happens because the bronchial tree takes a while to heal. A lasting cough ...

  11. Electrophysiological studies on ciguatera poisoning in man (Part II).

    PubMed

    Cameron, J; Flowers, A E; Capra, M F

    1991-01-01

    Fifteen cases of acute ciguatera poisoning were subjected to electrical studies on the sural and common peroneal nerves. Significant slowing of sensory conduction velocity and prolongation of the absolute refractory, relative refractory and supernormal periods were recorded. These findings indirectly suggest that ciguatoxin causes an abnormally prolonged sodium channel opening in nerve membranes.

  12. Monoterpenoid terpinen-4-ol exhibits anticonvulsant activity in behavioural and electrophysiological studies.

    PubMed

    Nóbrega, Franklin F F; Salvadori, Mirian G S S; Masson, Cintia J; Mello, Carlos F; Nascimento, Tiago S; Leal-Cardoso, José H; de Sousa, Damião P; Almeida, Reinaldo N

    2014-01-01

    Terpinen-4-ol (4TRP) is a monoterpenoid alcoholic component of essential oils obtained from several aromatic plants. We investigated the psychopharmacological and electrophysiological activities of 4TRP in male Swiss mice and Wistar rats. 4TRP was administered intraperitoneally (i.p.) at doses of 25 to 200 mg/kg and intracerebroventricularly (i.c.v.) at concentrations of 10, 20, and 40 ng/2 μL. For in vitro experiments, 4TRP concentrations were 0.1 mM and 1.0 mM. 4TRP (i.p.) inhibited pentylenetetrazol- (PTZ-) induced seizures, indicating anticonvulsant effects. Electroencephalographic recordings showed that 4TRP (i.c.v.) protected against PTZ-induced seizures, corroborating the behavioural results. To determine whether 4TRP exerts anticonvulsant effects via regulation of GABAergic neurotransmission, we measured convulsions induced by 3-mercapto-propionic acid (3-MP). The obtained results showed involvement of the GABAergic system in the anticonvulsant action exerted by 4TRP, but flumazenil, a selective antagonist of the benzodiazepine site of the GABAA receptor, did not reverse the anticonvulsant effect, demonstrating that 4TRP does not bind to the benzodiazepine-binding site. Furthermore, 4TRP decreased the sodium current through voltage-dependent sodium channels, and thus its anticonvulsant effect may be related to changes in neuronal excitability because of modulation of these channels.

  13. Semi-automatic microdrive system for positioning electrodes during electrophysiological recordings from rat brain

    NASA Astrophysics Data System (ADS)

    Dabrowski, Piotr; Kublik, Ewa; Mozaryn, Jakub

    2015-09-01

    Electrophysiological recording of neuronal action potentials from behaving animals requires portable, precise and reliable devices for positioning of multiple microelectrodes in the brain. We propose a semi-automatic microdrive system for independent positioning of up to 8 electrodes (or tetrodes) in a rat (or larger animals). Device is intended to be used in chronic, long term recording applications in freely moving animals. Our design is based on independent stepper motors with lead screws which will offer single steps of ~ μm semi-automatically controlled from the computer. Microdrive system prototype for one electrode was developed and tested. Because of the lack of the systematic test procedures dedicated to such applications, we propose the evaluation of the prototype similar to ISO norm for industrial robots. To this end we designed and implemented magnetic linear and rotary encoders that provided information about electrode displacement and motor shaft movement. On the basis of these measurements we estimated repeatability, accuracy and backlash of the drive. According to the given assumptions and preliminary tests, the device should provide greater accuracy than hand-controlled manipulators available on the market. Automatic positioning will also shorten the course of the experiment and improve the acquisition of signals from multiple neuronal populations.

  14. Creating a movement heuristic for voluntary action: electrophysiological correlates of movement-outcome learning.

    PubMed

    Bednark, Jeffery G; Reynolds, John N J; Stafford, Tom; Redgrave, Peter; Franz, Elizabeth A

    2013-03-01

    Performance of voluntary behavior requires the selection of appropriate movements to attain a desired goal. We propose that the selection of voluntary movements is often contingent on the formation of a movement heuristic or set of internal rules governing movement selection. We used event-related potentials (ERPs) to identify the electrophysiological correlates of the formation of movement heuristics during movement-outcome learning. In two experiments, ERPs from non-learning control tasks were compared to a movement-learning task in which a movement heuristic was formed. We found that novelty P3 amplitude was negatively correlated with improved performance in the movement-learning task. Additionally, enhancement of novelty P3 amplitude was observed during learning even after controlling for memory, attentional and inter-stimulus interval parameters. The feedback correct-related positivity (fCRP) was only elicited by sensory effects following intentional movements. These findings extend previous studies demonstrating the role of the fCRP in performance monitoring and the role of the P3 in learning. In particular, the present study highlights an integrative role of the fCRP and the novelty P3 for the acquisition of movement heuristics. While the fCRP indicates that the goal of intentional movements has been attained, the novelty P3 engages stimulus-driven attentional mechanisms to determine the primary aspects of movement and context required to elicit the sensory effect.

  15. Luigi Galvani and animal electricity: two centuries after the foundation of electrophysiology.

    PubMed

    Piccolino, M

    1997-10-01

    Luigi Galvani and his famous experiments on frogs carried out in the second half of the 18th century belong more to legend than to the history of science. Galvani not only laid the foundations of a new science, electrophysiology, but also opened the way for the invention of the electric battery, and thus for the development of the physical investigations of electricity. However, in spite of the widespread celebration of his work, Galvani's scientific endeavours have been largely misrepresented in the history of science. The scholar of Bologna has a stereotyped image as an 'occasional' scientist, who started his studies by chance, largely ignored the scientific theories of his time and wandered aimlessly in mental elaborations until the physicist of Pavia, Alessandro Volta, entered the field, correctly interpreted Galvani's results and eventually developed the electric battery. With the present understanding of electrical phenomena in excitable membranes, it is now time to reconsider the real matter raised by Galvani's discoveries and by his hypothesis of an intrinsic 'animal electricity', and to make a clearer evaluation of a revolutionary phase of scientific progress.

  16. Monoterpenoid Terpinen-4-ol Exhibits Anticonvulsant Activity in Behavioural and Electrophysiological Studies

    PubMed Central

    Nóbrega, Franklin F. F.; Salvadori, Mirian G. S. S.; Masson, Cintia J.; Mello, Carlos F.; Nascimento, Tiago S.; Leal-Cardoso, José H.; de Sousa, Damião P.; Almeida, Reinaldo N.

    2014-01-01

    Terpinen-4-ol (4TRP) is a monoterpenoid alcoholic component of essential oils obtained from several aromatic plants. We investigated the psychopharmacological and electrophysiological activities of 4TRP in male Swiss mice and Wistar rats. 4TRP was administered intraperitoneally (i.p.) at doses of 25 to 200 mg/kg and intracerebroventricularly (i.c.v.) at concentrations of 10, 20, and 40 ng/2 μL. For in vitro experiments, 4TRP concentrations were 0.1 mM and 1.0 mM. 4TRP (i.p.) inhibited pentylenetetrazol- (PTZ-) induced seizures, indicating anticonvulsant effects. Electroencephalographic recordings showed that 4TRP (i.c.v.) protected against PTZ-induced seizures, corroborating the behavioural results. To determine whether 4TRP exerts anticonvulsant effects via regulation of GABAergic neurotransmission, we measured convulsions induced by 3-mercapto-propionic acid (3-MP). The obtained results showed involvement of the GABAergic system in the anticonvulsant action exerted by 4TRP, but flumazenil, a selective antagonist of the benzodiazepine site of the GABAA receptor, did not reverse the anticonvulsant effect, demonstrating that 4TRP does not bind to the benzodiazepine-binding site. Furthermore, 4TRP decreased the sodium current through voltage-dependent sodium channels, and thus its anticonvulsant effect may be related to changes in neuronal excitability because of modulation of these channels. PMID:25180069

  17. Calcein labelling and electrophysiology: insights on coral tissue permeability and calcification

    PubMed Central

    Tambutté, Eric; Tambutté, Sylvie; Segonds, Natacha; Zoccola, Didier; Venn, Alexander; Erez, Jonathan; Allemand, Denis

    2012-01-01

    The mechanisms behind the transfer of molecules from the surrounding sea water to the site of coral calcification are not well understood, but are critical for understanding how coral reefs are formed. We conducted experiments with the fluorescent dye calcein, which binds to calcium and is incorporated into growing calcium carbonate crystals, to determine the permeability properties of coral cells and tissues to this molecule, and to determine how it is incorporated into the coral skeleton. We also compared rates of calcein incorporation with rates of calcification measured by the alkalinity anomaly technique. Finally, by an electrophysiological approach, we investigated the electrical resistance of coral tissues in order to better understand the role of tissues in ionic permeability. Our results show that (i) calcein passes through coral tissues by a paracellular pathway, (ii) intercellular junctions control and restrict the diffusion of molecules, (iii) intercellular junctions should have pores of a size higher than 13 Å and lower than 20 nm, and (iv) the resistance of the tissues owing to paracellular junctions has a value of 477 ± 21 Ohm cm2. We discuss the implication of our results for the transport of calcium involved in the calcification process. PMID:21613296

  18. Electrophysiological effects of 12C on patients undergoing heavy ions therapy at GSI: a pilot study

    NASA Astrophysics Data System (ADS)

    Sannita, W. G.; Narici, L.; Debus, J.; Carozzo, S.; Saturno, M.; Schardt, D.; Schulz-Ertner, D.

    Phosphenes light flashes observed in space have been attributed to heavy ions interfering with the retina photoreceptors However their generating mechanisms are still undefined and neurons of the retina and non-ocular visual structures are as sensitive to ionizing agents as retinal photoreceptors Multiple sources are therefore possible that could question safety in manned space travel Patients undergoing 12C ion therapy of skull tumors also involving the anterior optic pathway often report phosphenes similar to those described by astronauts and volunteers in accelerator experiments In a pilot study their occurrence either within each beam pulse or shortly after it in case of very short pulses correlated with the beam position and local dose deposited near the optic nerve or eye during irradiation Further research is in progress at the GSI Biophysics facilities in Darmstadt FRG Purposes of the study are 1- to identify electrophysiological cortical concomitants of phosphenes 2- to correlate phosphenes with irradiated portions of the anterior visual pathways and with known basic mechanisms of vision and 3- to obtain information to be used in the understanding of phosphenes observed in space We will present preliminary results from the first measurements

  19. Electrophysiological effects of the aqueous extract of Averrhoa carambola L. leaves on the guinea pig heart.

    PubMed

    Vasconcelos, C M L; Araújo, M S; Conde-Garcia, E A

    2006-07-01

    This work aims to describe some electrophysiological changes promoted by the aqueous extract (AEx) from Averrhoa carambola leaves in guinea pig heart. The experiments were carried out on isolated heart or on right atrium-ventricle preparations. In 6 hearts, the extract induced many kinds of atrioventricular blocks (1st, 2nd, and 3rd degrees); increased the QT interval from 229+/-23 to 264+/-19 ms; increased the QRS complex duration from 27+/-3.1 to 59+/-11 ms, and depressed the cardiac rate from 136+/-17 to 89+/-14b pm. Furthermore, it decreased the conduction velocity of atrial impulse (17+/-3%); reduced the intraventricular pressure (86+/-6%), and increased the conduction time between the right atrium and the His bundle (27+/-6.5%). The conduction time from the His bundle to the right ventricle was not altered. Atropine sulfate did not change either the electrocardiographic parameters or the intraventricular pressure effects promoted by the A. carambola AEx. Based on these results, the popular use of such extracts should be avoided because it can promote electrical and mechanical changes in the normal heart.

  20. Heat stress responses modulate calcium regulations and electrophysiological characteristics in atrial myocytes.

    PubMed

    Chen, Yao-Chang; Kao, Yu-Hsun; Huang, Chun-Feng; Cheng, Chen-Chuan; Chen, Yi-Jen; Chen, Shih-Ann

    2010-04-01

    Heat stress-induced responses change the ionic currents and calcium homeostasis. However, the molecular insights into the heat stress responses on calcium homeostasis remain unclear. The purposes of this study were to examine the mechanisms of heat stress responses on calcium handling and electrophysiological characteristics in atrial myocytes. We used indo-1 fluorimetric ratio technique and whole-cell patch clamp to investigate the intracellular calcium, action potentials, and ionic currents in isolated rabbit single atrial cardiomyocytes with or without (control) exposure to heat stress (43 degrees C, 15 min) 5+/-1 h before experiments. The expressions of sarcoplasmic reticulum ATPase (SERCA2a), and Na(+)-Ca(2+) exchanger (NCX) in the control and heat stress-treated atrial myocytes were evaluated by Western blot and real-time PCR. As compared with control myocytes, the heat stress-treated myocytes had larger sarcoplasmic reticulum calcium content and larger intracellular calcium transient with a shorter decay portion. Heat stress-treated myocytes also had larger L-type calcium currents, transient outward potassium currents, but smaller NCX currents. Heat stress responses increased the protein expressions, SERCA2a, NCX, and heat shock protein. However, heat stress responses did not change the RNA expression of SERCA2a and NCX. In conclusion, heat stress responses change calcium handling through protein but not RNA regulation.

  1. A Computational Model Integrating Electrophysiology, Contraction, and Mitochondrial Bioenergetics in the Ventricular Myocyte

    PubMed Central

    Cortassa, Sonia; Aon, Miguel A.; O'Rourke, Brian; Jacques, Robert; Tseng, Hsiang-Jer; Marbán, Eduardo; Winslow, Raimond L.

    2006-01-01

    An intricate network of reactions is involved in matching energy supply with demand in the heart. This complexity arises because energy production both modulates and is modulated by the electrophysiological and contractile activity of the cardiac myocyte. Here, we present an integrated mathematical model of the cardiac cell that links excitation-contraction coupling with mitochondrial energy generation. The dynamics of the model are described by a system of 50 ordinary differential equations. The formulation explicitly incorporates cytoplasmic ATP-consuming processes associated with force generation and ion transport, as well as the creatine kinase reaction. Changes in the electrical and contractile activity of the myocyte are coupled to mitochondrial energetics through the ATP, Ca2+, and Na+ concentrations in the myoplasmic and mitochondrial matrix compartments. The pseudo steady-state relationship between force and oxygen consumption at various stimulus frequencies and external Ca2+ concentrations is reproduced in both model simulations and direct experiments in cardiac trabeculae under normoxic conditions, recapitulating the linearity between cardiac work and respiration in the heart. Importantly, the model can also reproduce the rapid time-dependent changes in mitochondrial NADH and Ca2+ in response to abrupt changes in workload. The steady-state and dynamic responses of the model were conferred by ADP-dependent stimulation of mitochondrial oxidative phosphorylation and Ca2+-dependent regulation of Krebs cycle dehydrogenases, illustrating how the model can be used as a tool for investigating mechanisms underlying metabolic control in the heart. PMID:16679365

  2. Retinal electrophysiology for toxicology studies: applications and limits of ERG in animals and ex vivo recordings.

    PubMed

    Rosolen, Serge Georges; Kolomiets, Bogdan; Varela, Oscar; Picaud, Serge

    2008-06-01

    Assessing retinal drug toxicity is becoming increasingly important as different molecules are now developed for the treatment of neurodegenerative diseases and vascular disorders. In pharmacology and toxicology, the electroretinogram (ERG) and the multielectrode array (MEA) recording techniques can be used to quantify the possible side effects of retino-active xenobiotics. Toxicity testing requires the use of rodent as well as non-rodent models for extrapolation to the human model when determining risk and safety. Animal species differ in their retinal anatomo-physiology: most rodents used in toxicology studies are essentially nocturnal species, whereas the non-rodent laboratory species normally used (e.g. dogs, pigs and monkeys) are diurnal. The ratio between the photoreceptor populations which varies from species to species, should be considered when designing the experiment protocol and the interpretation. The described ERG procedures are designed to comply with all applicable good laboratory practice standards. Use of these procedures should yield an acceptable level of intra- and inter-subject variability for compiling a historical database, and for detecting possible retinal toxicity in animal studies. They could therefore be used as specific and standardized tools for screening of potential retinotoxic molecules in drug discovery and development in order to compare methods and results with those obtained in human electrophysiological assessments. Recording of ganglion cell light responses on ex vivo retina with the MEA technique can further demonstrate how retino-active xenobiotics affect retinal visual information processing by eliminating potential obstacles related to bioavailability and blood barrier permeability.

  3. Spatial attention facilitates assembly of the briefest percepts: Electrophysiological evidence from color fusion.

    PubMed

    Akyürek, Elkan G; van Asselt, E Manon

    2015-12-01

    When two different color stimuli are presented in rapid succession, the resulting percept is sometimes that of a mixture of both colors, due to a perceptual process called color fusion. Although color fusion might seem to occur very early in the visual pathway, and only happens across the briefest of stimulus presentation intervals (< 50 ms), the present study showed that spatial attention can alter the fusion process. In a series of experiments, spatial cues were presented that either validly indicated the location of a pair of (different) color stimuli in successive stimulus arrays, or did not, pointing toward isoluminant gray distractors in the other visual hemifield. Increased color fusion was observed for valid cues across a range of stimulus durations, at the expense of individual color reports. By contrast, perception of repeated, same-color stimulus pairs did not change, suggesting that the enhancement was specific to fusion, not color discrimination per se. Electrophysiological measures furthermore showed that the amplitude of the N1, N2pc, and P3 components of the ERP were differentially modulated during the perception of individual and fused colors, as a function of cueing and stimulus duration. Fusion itself, collapsed across cueing conditions, was reflected uniquely in N1 amplitude. Overall, the results suggest that spatial attention enhances color fusion and decreases competition between stimuli, constituting an adaptive slowdown in service of temporal integration.

  4. A simple, low-cost and fast Peltier thermoregulation set-up for electrophysiology.

    PubMed

    Corrèges, P; Bugnard, E; Millerin, C; Masiero, A; Andrivet, J P; Bloc, A; Dunant, Y

    1998-09-01

    Most of the parameters recorded in electrophysiology are strongly temperature dependent. In order to control temperature fluctuations we have built a system that ensures an accurate thermoregulation of the recording chamber. Temperature of physiological preparations can be changed relatively quickly (about 8 degrees C/min) and with a good accuracy (+/- 0.5 degrees C) without inducing thermal oscillations. Contrary to other thermoregulating devices, the temperature regulation is not carried out through the perfused medium but directly at the bottom of the chamber where a 3-cm2 Peltier element has been placed. The element is driven by a dedicated electronic device which controls the amount and the direction of the current flowing across the Peltier thermocouple. All construction details and the appropriate electrical circuits are provided. Using this home-made device, the steady-state chamber temperature could be precisely monitored with a resolution of +/- 0.1 degrees C in a range of 0-40 degrees C. This set-up was tested in experiments designed to evaluate the temperature dependence of synaptic transmission in the Torpedo nerve electroplate synapses and of calcium currents recorded from isolated nerve cells. This low-cost method is suitable for a wide range of applications.

  5. Management of acute coronary occlusion during percutaneous transluminal coronary angioplasty: experience of complications in a hospital without on site facilities for cardiac surgery.

    PubMed Central

    Richardson, S G; Morton, P; Murtagh, J G; O'Keeffe, D B; Murphy, P; Scott, M E

    1990-01-01

    OBJECTIVE--To determine whether percutaneous transluminal coronary angioplasty may be safely performed in cardiology centres in the United Kingdom without immediate on site cardiac surgical cover for complications arising at angioplasty. DESIGN--Retrospective review of coronary angioplasties and complications in a hospital without on site cardiac surgical cover. SETTING--All angioplasties were performed in the catheterisation laboratory of the Belfast City Hospital. Revascularisation surgery for complicated coronary angioplasty was performed in the cardiac surgical unit of the Royal Victoria Hospital, 2.4 km away from the catheterisation laboratory. PATIENTS--540 Coronary angioplasties were performed on 512 patients between late 1982 and November 1988. Indications included stable angina, unstable rest angina, and suitable coronary disease at coronary arteriography after myocardial infarction. MAIN OUTCOME MEASURES--In hospital mortality after complicated coronary angioplasty and delay to surgical revascularisation after acute coronary occlusion at angioplasty. RESULTS--Coronary angioplasty was successful in 444 cases (82%). Acute coronary occlusion occurred in 35 cases (6.5%). Twelve patients required urgent revascularisation surgery and were transferred safely to the surgical unit; none of these patients died. A mean delay of 268 minutes (range 180-390 minutes) occurred before revascularisation compared with 273 minutes (range 108-420 minutes) in the Royal Victoria Hospital, where on site surgical cover was available. The principal cause of delay was the wait for a cardiac operating theatre to become available and not the transfer time between hospitals. Five deaths occurred after coronary angioplasty, a mortality of 0.9%. Three deaths were related to acute coronary occlusion. The absence of immediate surgical help did not influence the outcome in any patient. CONCLUSION--With careful selection of patients coronary angioplasty may be safely performed in a hospital

  6. Impaired Fasting Glucose and Recurrent Cardiovascular Disease among Survivors of a First Acute Myocardial Infarction: Evidence of a Sex Difference ? The Western New York Experience

    PubMed Central

    Donahue, Richard P; Dorn, Joan M; Stranges, Saverio; Swanson, Mya; Hovey, Kathleen; Trevisan, Maurizio

    2009-01-01

    Background and aims There is little epidemiological evidence regarding the association of impaired glucose metabolism with recurrent cardiovascular events. We therefore examined potential sex differences in the effect of impaired fasting glucose (IFG) on recurrent cardiovascular disease (CVD) in a community-based study of survivors of a first acute myocardial infarction (MI). Methods and results This report focuses on 1,226 incident MI cases (28.4% women) discharged alive from area hospitals in the Western New York Acute MI Study (1996–2004). Deaths and underlying cause of death were determined via query of the National Death Index (Plus) Retrieval Program with follow-up through December 31, 2004. Outcomes reported included fatal or nonfatal coronary heart disease (CHD) or coronary revascularization surgery and total stroke. Traditional CHD risk factors and other explanatory variables were determined by clinical examination after the first acute event. Impaired fasting glucose was defined as fasting blood glucose between 100 and 125 mg/dl. During a mean follow-up of 4.5 years, there were 91 recurrent events (26.1%) in women and 173 recurrent events (19.7%) in men. After multivariable adjustment, the hazard ratios for recurrent cardiovascular events were 1.96 (95% CI: 1.15–3.16) and 2.59 (1.56–4.30) in women with IFG and with diabetes, respectively, compared to normoglycemic women. Among men, neither IFG nor diabetes was independently related to risk of recurrence. Conclusions In this study, IFG was a strong risk factor for recurrent cardiovascular events only among women. These results suggest that increased cardiovascular risk in MI survivors begins at lower glucose levels in women than men. PMID:20227262

  7. Electrophysiological biomarkers in spinal muscular atrophy: proof of concept

    PubMed Central

    David Arnold, W; Porensky, Paul N; McGovern, Vicki L; Iyer, Chitra C; Duque, Sandra; Li, Xiaobai; Meyer, Kathrin; Schmelzer, Leah; Kaspar, Brian K; Kolb, Stephen J; Kissel, John T; Burghes, Arthur H M

    2014-01-01

    Objective Preclinical therapies that restore survival motor neuron (SMN) protein levels can dramatically extend survival in spinal muscular atrophy (SMA) mouse models. Biomarkers are needed to effectively translate these promising therapies to clinical trials. Our objective was to investigate electrophysiological biomarkers of compound muscle action potential (CMAP), motor unit number estimation (MUNE) and electromyography (EMG) using an SMA mouse model. Methods Sciatic CMAP, MUNE, and EMG were obtained in SMNΔ7 mice at ages 3–13 days and at 21 days in mice with SMN selectively reduced in motor neurons (ChATCre). To investigate these measures as biomarkers of treatment response, measurements were obtained in SMNΔ7 mice treated with antisense oligonucleotide (ASO) or gene therapy. Results CMAP was significantly reduced in SMNΔ7 mice at days 6–13 (P < 0.01), and MUNE was reduced at days 7–13 (P < 0.01). Fibrillations were present on EMG in SMNΔ7 mice but not controls (P = 0.02). Similar findings were seen at 21 days in ChATCre mice. MUNE in ASO-treated SMNΔ7 mice were similar to controls at day 12 and 30. CMAP reduction persisted in ASO-treated SMNΔ7 mice at day 12 but was corrected at day 30. Similarly, CMAP and MUNE responses were corrected with gene therapy to restore SMN. Interpretation These studies confirm features of preserved neuromuscular function in the early postnatal period and subsequent motor unit loss in SMNΔ7 mice. SMN restoring therapies result in preserved MUNE and gradual repair of CMAP responses. This provides preclinical evidence for the utilization of CMAP and MUNE as biomarkers in future SMA clinical trials. PMID:24511555

  8. Intraoperative electrophysiological evaluations of macular function during peripheral scleral indentation

    PubMed Central

    Akiyama, Goichi; Matsumoto, Celso Soiti; Shinoda, Kei; Terauchi, Gaku; Matsumoto, Harue; Watanabe, Emiko; Iwata, Takeshi; Mizota, Atsushi; Miyake, Yozo

    2016-01-01

    Scleral indentation is widely used to examine the peripheral fundus, however it can increase the intraocular pressure (IOP) to high levels which can then affect retinal function. We evaluated the effects of scleral indentation on the macular function electrophysiologically. Intraoperative focal macular electroretinograms (iFMERGs) were recorded with and without controlling the IOP in 7 eyes. Without IOP control, the IOP increased from 21.7 ± 4.9 to 92.7 ± 20.2 mmHg significantly (P = 0.020) and the amplitudes of the b-wave (from 6.29 ± 1.160 to 3.71 ± 1.98 uV, P = 0.007), on-photopic negative response (from 2.29 ± 0.99 to 0.72 ± 0.47 uV, on-PhNR, P = 0.005), and d-wave (from 2.57 ± 0.41 to 1.64 ± 0.69 uV, P = 0.007) decreased significantly soon after beginning the indentation. All values returned to the baseline levels after releasing the indentation. In the eyes with IOP controlled, the IOP and the amplitude of all components did not change significantly during and after the indentation except the on-PhNR amplitude which was significantly reduced during the indentation. The changes in the iFMERGs and macular function caused by scleral indentation were transient and reversible. The changes can be minimized by controlling the IOP. PMID:27762313

  9. [Electrophysiologic effects of amiodarone in Wolf-Parkinson-White syndrome].

    PubMed

    Touboul, P; Porte, J; Huerta, F; Delahaye, J P

    1976-08-01

    Eight patients with WPW syndrome were catheterised and, during the course of this investigation, the electrophysiological effects of amiodarone were assessed. By registering the potentials of the bundle of His and by using the stimulus-test technique, we were able to measure the refractory periods of the atrium and of the normal and accessory conducting pathways both before and during the first 40 minutes after an intra-atrial injection of 5 mg/kg of amiodarone chlorhydrate. The action of the conduction time was also studied. In the five cases in which we were able to measure it, the effective refractory period of the abnormal pathway increased, which led in two instances to the temporary suppression of all pre-excitation. At the same time, it was repeatedly found that the refractory periods of the A-V node were increased: the effective refractory period in 3/3 cases, and the functional refractory period in 2/2 cases. The effective refractory period of the right atrium was increased in 5 cases, and did not change in the others. The intranodal conduction time (A-H- interval) was always increased after amiodarone. Finally, in three patients runs of reciprocal tachycardia could be initiated by premature atrial stimulation. In one case, this was no longer possible after amiodarone. In the other two cases, although the attacks could still be brought on, they were slower because of the lengthening of the A-H interval. These findings explain why amiodarone is effective in controlling the tachycardia of WPW syndrome.

  10. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography

    PubMed Central

    Valente, Maurizio; Krstajic, Nikola; Biella, Gabriele E. M.

    2016-01-01

    Despite the continuous improvement in medical imaging technology, visualizing the spinal cord poses severe problems due to structural or incidental causes, such as small access space and motion artifacts. In addition, positional guidance on the spinal cord is not commonly available during surgery, with the exception of neuronavigation techniques based on static pre-surgical data and of radiation-based methods, such as fluoroscopy. A fast, bedside, intraoperative real-time imaging, particularly necessary during the positioning of endoscopic probes or tools, is an unsolved issue. The objective of our work, performed on experimental rats, is to demonstrate potential intraoperative spinal cord imaging and probe guidance by optical coherence tomography (OCT). Concurrently, we aimed to demonstrate that the electromagnetic OCT irradiation exerted no particular effect at the neuronal and synaptic levels. OCT is a user-friendly, low-cost and endoscopy-compatible photonics-based imaging technique. In particular, by using a Fourier-domain OCT imager, operating at 850 nm wavelength and scanning transversally with respect to the spinal cord, we have been able to: 1) accurately image tissue structures in an animal model (muscle, spine bone, cerebro-spinal fluid, dura mater and spinal cord), and 2) identify the position of a recording microelectrode approaching and inserting into the cord tissue 3) check that the infrared radiation has no actual effect on the electrophysiological activity of spinal neurons. The technique, potentially extendable to full three-dimensional image reconstruction, shows prospective further application not only in endoscopic intraoperative analyses and for probe insertion guidance, but also in emergency and adverse situations (e.g. after trauma) for damage recognition, diagnosis and fast image-guided intervention. PMID:27050096

  11. Plant volatiles influence electrophysiological and behavioral responses of Lygus hesperus.

    PubMed

    Williams, Livy; Blackmer, Jacquelyn L; Rodriguez-Saona, Cesar; Zhu, Su

    2010-05-01

    Previous laboratory studies have shown that the mirid Lygus hesperus is attracted to volatiles emitted from alfalfa; feeding damage increases the amounts of several of these volatiles, and visual cues can enhance attraction further. The present study tested single plant volatiles in electrophysiological and behavioral trials with L. hesperus. Electroantennogram (EAG) analyses indicated that antennae responded to most plant volatiles included in the test, and that when gender differences were observed, males usually were more responsive than females. Antennal responses to the alcohols ((E)-3-hexenol, (Z)-3-hexenol, 1-hexanol), the acetate (E)-2-hexenyl acetate, and the aldehyde (E)-2-hexenal were among the strongest. Moderate responses were observed for (E)-beta-ocimene, (E,E)-alpha-farnesene, (+/-)-linalool, and methyl salicylate. A dose dependent response was not observed for several terpenes (beta-myrcene, beta-caryophyllene, (+)-limonene, or both (R)-(+)- and (S)-(-)-alpha-pinenes). EAG responses, however, were not always consistent with behavioral assays. In Y-tube bioassays, males did not exhibit a positive behavioral response to any of the compounds tested. Instead, males were repelled by (E)-2-hexenyl acetate, (+/-)-linalool, (E,E)-alpha-farnesene, and methyl salicylate. In contrast, female L. hesperus moved upwind towards (R)-(+)-alpha-pinene, (E)-beta-ocimene, and (E,E)-alpha-farnesene, and showed a negative response towards (Z)-3-hexen-1-ol, (S)-(-)-alpha-pinene, and methyl salicylate. This study emphasizes the use of multiple approaches to better understand host plant finding in the generalist herbivore L. hesperus.

  12. Visual adaptation provides objective electrophysiological evidence of facial identity discrimination.

    PubMed

    Retter, Talia L; Rossion, Bruno

    2016-07-01

    Discrimination of facial identities is a fundamental function of the human brain that is challenging to examine with macroscopic measurements of neural activity, such as those obtained with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Although visual adaptation or repetition suppression (RS) stimulation paradigms have been successfully implemented to this end with such recording techniques, objective evidence of an identity-specific discrimination response due to adaptation at the level of the visual representation is lacking. Here, we addressed this issue with fast periodic visual stimulation (FPVS) and EEG recording combined with a symmetry/asymmetry adaptation paradigm. Adaptation to one facial identity is induced through repeated presentation of that identity at a rate of 6 images per second (6 Hz) over 10 sec. Subsequently, this identity is presented in alternation with another facial identity (i.e., its anti-face, both faces being equidistant from an average face), producing an identity repetition rate of 3 Hz over a 20 sec testing sequence. A clear EEG response at 3 Hz is observed over the right occipito-temporal (ROT) cortex, indexing discrimination between the two facial identities in the absence of an explicit behavioral discrimination measure. This face identity discrimination occurs immediately after adaptation and disappears rapidly within 20 sec. Importantly, this 3 Hz response is not observed in a control condition without the single-identity 10 sec adaptation period. These results indicate that visual adaptation to a given facial identity produces an objective (i.e., at a pre-defined stimulation frequency) electrophysiological index of visual discrimination between that identity and another, and provides a unique behavior-free quantification of the effect of visual adaptation.

  13. Acute Motor Axonal Neuropathy (Aman) With Motor Conduction Blocks In Childhood; Case Report

    PubMed Central

    Yildirim, Serhan; Adviye, Rahşan; Gül, Hakan Levent; Türk Börü, Ülkü

    2016-01-01

    Objective Acute motor axonal neuropathy (AMAN), characterized with decreased compound muscle action potentials (CMAP) and absence of demyelinating findings in electrophysiological studies, is a subtype of Guillain-Barre Syndrome (GBS). A 4 yr-old male patient presented with ascending weakness, dysarthria and dysphagia to İstanbul Dr. Lütfi Kırdar Kartal Training and Research Hospital Neurology outpatient for three days to in 2012. Dysphonia, restricted eye movements, flaccid tetraplegia and areflexia were found in neurological examination. There were motor conduction blocks in all peripheral nerves in electrophysiological studies.According to these findings the patient was diagnosed as Acute Inflammatory Demyelinating Polyradiculoneuropathy (AIDP). Reduction of CMAP amplitudes in posterior tibial nerve, absence of CMAPs in median, ulnar and peroneal nerves and loss of motor conduction blocks were found in following electrophysiological studies. According to these findings, patient was diagnosed as AMAN. Motor conduction blocks may appear in early stage of AMAN and they disappear in later examinations. That’s why electrophysiological studies must be repeated in patients with GBS. PMID:27057191

  14. Electrophysiological and Structural Remodeling in Heart Failure Modulate Arrhythmogenesis. 1D Simulation Study

    PubMed Central

    Gomez, Juan F.; Cardona, Karen; Romero, Lucia; Ferrero, Jose M.; Trenor, Beatriz

    2014-01-01

    Background Heart failure is a final common pathway or descriptor for various cardiac pathologies. It is associated with sudden cardiac death, which is frequently caused by ventricular arrhythmias. Electrophysiological remodeling, intercellular uncoupling, fibrosis and autonomic imbalance have been identified as major arrhythmogenic factors in heart failure etiology and progression. Objective In this study we investigate in silico the role of electrophysiological and structural heart failure remodeling on the modulation of key elements of the arrhythmogenic substrate, i.e., electrophysiological gradients and abnormal impulse propagation. Methods Two different mathematical models of the human ventricular action potential were used to formulate models of the failing ventricular myocyte. This provided the basis for simulations of the electrical activity within a transmural ventricular strand. Our main goal was to elucidate the roles of electrophysiological and structural remodeling in setting the stage for malignant life-threatening arrhythmias. Results Simulation results illustrate how the presence of M cells and heterogeneous electrophysiological remodeling in the human failing ventricle modulate the dispersion of action potential duration and repolarization time. Specifically, selective heterogeneous remodeling of expression levels for the Na+/Ca2+ exchanger and SERCA pump decrease these heterogeneities. In contrast, fibroblast proliferation and cellular uncoupling both strongly increase repolarization heterogeneities. Conduction velocity and the safety factor for conduction are also reduced by the progressive structural remodeling during heart failure. Conclusion An extensive literature now establishes that in human ventricle, as heart failure progresses, gradients for repolarization are changed significantly by protein specific electrophysiological remodeling (either homogeneous or heterogeneous). Our simulations illustrate and provide new insights into this

  15. [Epidemiological, clinical, cytologic and immunophenotypic aspects of acute leukemia in children: the experience at the hematology laboratory of IBN SINA University Hospital Center].

    PubMed

    Doumbia, Mariam; Uwingabiye, Jean; Bissan, Aboubacar; Rachid, Razine; Benkirane, Souad; Masrar, Azlarab

    2016-01-01

    The aim of this study was to describe epidemiological, cytologic and immunophenotypic aspects of acute leukemias (AL) in children diagnosed at IBN SINA University Hospital Center and to determine the concordance between cytology and immunophenotyping results. This is a cross-sectional study conducted in the hematology laboratory of IBN SINA University Hospital Center between June 2012 and May 2014. Among the 104 cases with diagnosed AL, 52% were boys with a sex-ratio H/F= 1.32, the average age was 5.7 years. The distribution of different types of AL was: lymphoid AL (LAL) (74%), myeloid (AML) (20.2%), biphenotypic AL (BAL) (65.8%). Among the LALs, 78% were classified as B LAL and 22% as T LAL. Clinical signs were mainly presented with tumor syndrome (73.1%), fever (61%) and hemorrhagic syndrome (50%). The most common blood count abnormalities were: thrombopenia (89.4%), anemia (86.5%), hyperleukocytosis (79.8%). The rate of peripheral and bone marrow blasts was statistically higher for LAL than for AML and BAL (p <0.001). The rate of relapse and mortality was 21.2% and 16. 3% respectively. Concordance rate between the results of cytology and of immunophenotyping was 92.7% for LAL and 82.6% for AML. Diagnosis of AL is always based primarily on cytology. Immunophenotyping allowed us to make a better distinction between acute leukemias. The management of paediatric AL is a major health problem which requires specialized care centers.

  16. Central review of cytogenetics is necessary for cooperative group correlative and clinical studies of adult acute leukemia: The Cancer and Leukemia Group B experience

    PubMed Central

    Mrózek, Krzysztof; Carroll, Andrew J.; Maharry, Kati; Rao, Kathleen W.; Patil, Shivanand R.; Pettenati, Mark J.; Watson, Michael S.; Arthur, Diane C.; Tantravahi, Ramana; Heerema, Nyla A.; Koduru, Prasad R. K.; Block, AnneMarie W.; Qumsiyeh, Mazin B.; Edwards, Colin G.; Sterling, Lisa J.; Holland, Kelsi B.; Bloomfield, Clara D.

    2009-01-01

    The Cancer and Leukemia Group B has performed central review of karyotypes submitted by institutional cytogenetics laboratories from patients with acute myeloid (AML) and acute lymphoblastic (ALL) leukemia since 1986. We assessed the role of central karyotype review in maintaining accurate, high quality cytogenetic data for clinical and translational studies using two criteria: the proportion of karyotypes rejected (i.e. inadequate), and, among accepted (i.e. adequate) cases, the proportion of karyotypes whose interpretation was changed on central karyotype review. We compared the first four years during which central karyotype review was performed with a recent four-year period and found that the proportion of rejected samples decreased significantly for both AML and ALL. However, during the latter period, central karyotype reviews still found 8% of AML and 16% of ALL karyotypes inadequate. Among adequate cases, the karyotype was revised in 26% of both AML and ALL samples. Some revisions resulted in changing the patients’ assignment to particular World Health Organization diagnostic categories and/or moving patients from one prognostic group to another. Overall, when both data on rejection rates and data on karyotype revisions made in accepted cases were considered together, 32% of AML and 38% of ALL samples submitted were either rejected or revised on central karyotype review during the recent 4-year period. These data underscore the necessity of continued central karyotype review in multi-institutional cooperative group studies. PMID:18636143

  17. Acute appendicitis: should the laparoscopic approach be proposed as the gold standard? Six-year experience in an Emergency Surgery Unit

    PubMed Central

    GUERCIO, G.; AUGELLO, G.; LICARI, L.; DAFNOMILI, A.; RASPANTI, C.; BAGARELLA, N.; FALCO, N.; ROTOLO, G.; FONTANA, T.; PORRELLO, C.; GULOTTA, G.

    2016-01-01

    Acute appendicitis is common in an Emergency Surgery Unit. Although the laparoscopic approach is a method accepted for its treatment, no strong data are available for determining how many procedures must an experienced surgeon carry out for obtaining all the advantages of this technique and if this approach can become the gold standard in the activity of a general emergency unit with senior surgeons variously skilled on the basic laparoscopy. 142 patients that underwent appendectomy (90 laparoscopic, 52 conventional) for acute appendicitis were enrolled in this institutional retrospective cohort study. The surgeons were classified with a descriptor-based grading and divided in two groups regarding the skill. The only relevant result of our study was the significant reduction of conversion rate in case of laparoscopic approach. No strong differences were found concerning the duration of the procedure and the hospital stay between the two groups. The rate of complications were very low in both groups. In conclusion, the experienced surgeons can easily perform a laparoscopic approach independently from the specific skill in this approach. PMID:27938536

  18. Atrial Fibrillation and Ventricular Arrhythmias: Sex Differences in Electrophysiology, Epidemiology, Clinical Presentation, and Clinical Outcomes.

    PubMed

    Gillis, Anne M

    2017-02-07

    Sex-specific differences in the epidemiology, pathophysiology, clinical presentation, clinical treatment, and clinical outcomes of atrial fibrillation (AF), sustained ventricular arrhythmias, and sudden cardiac death are recognized. Sex hormones cause differences in cardiac electrophysiological parameters between men and women that may affect the risk for arrhythmias. The incidence and prevalence of AF is lower in women than in men. However, because women live longer and AF prevalence increases with age, the absolute number of women with AF exceeds that of men. Women with AF are more symptomatic, present with more atypical symptoms, and report worse quality of life in comparison with men. Female sex is an independent risk factor for death or stroke attributable to AF. Oral anticoagulation therapy for stroke prevention has similar efficacy for men and women, but older women treated with warfarin have a higher residual risk of stroke in comparison with men. Women with AF are less likely to receive rhythm control antiarrhythmic drug therapy, electric cardioversion, or catheter ablation in comparison with men. The incidence and prevalence of sustained ventricular arrhythmias and sudden cardiac death are lower in women than in men. Women receiving implantable cardioverter defibrillators for primary prevention of sudden cardiac death are less likely to experience sustained ventricular arrhythmias in comparison with men. In contrast, women receiving a cardiac resynchronization therapy implantable cardioverter defibrillator for the treatment of heart failure are more likely to benefit than men. Women are less likely to be referred for implantable cardioverter defibrillator therapy despite current guideline recommendations. Women are more likely to experience a significant complication related to implantable cardioverter defibrillator implantation in comparison with men. Whether sex differences in treatment decisions reflect patient preferences or treatment biases requires

  19. 3D Image-Guided Automatic Pipette Positioning for Single Cell Experiments in vivo

    PubMed Central

    Long, Brian; Li, Lu; Knoblich, Ulf; Zeng, Hongkui; Peng, Hanchuan

    2015-01-01

    We report a method to facilitate single cell, image-guided experiments including in vivo electrophysiology and electroporation. Our method combines 3D image data acquisition, visualization and on-line image analysis with precise control of physical probes such as electrophysiology microelectrodes in brain tissue in vivo. Adaptive pipette positioning provides a platform for future advances in automated, single cell in vivo experiments. PMID:26689553

  20. A proposal for a test method for assessment of hazard property HP 12 ("Release of an acute toxic gas") in hazardous waste classification - Experience from 49 waste.

    PubMed

    Hennebert, Pierre; Samaali, Ismahen; Molina, Pauline

    2016-12-01

    A stepwise method for assessment of the HP 12 is proposed and tested with 49 waste samples. The hazard property HP 12 is defined as "Release of an acute toxic gas": waste which releases acute toxic gases (Acute Tox. 1, 2 or 3) in contact with water or an acid. When a waste contains a substance assigned to one of the following supplemental hazards EUH029, EUH031 and EUH032, it shall be classified as hazardous by HP 12 according to test methods or guidelines (EC, 2014a, 2014b). When the substances with the cited hazard statement codes react with water or an acid, they can release HCl, Cl2, HF, HCN, PH3, H2S, SO2 (and two other gases very unlikely to be emitted, hydrazoic acid HN3 and selenium oxide SeO2 - a solid with low vapor pressure). Hence, a method is proposed:For a set of 49 waste, water addition did not produce gas. Nearly all the solid waste produced a gas in contact with hydrochloric acid in 5 min in an automated calcimeter with a volume >0.1L of gas per kg of waste. Since a plateau of pressure is reached only for half of the samples in 5 min, 6 h trial with calorimetric bombs or glass flasks were done and confirmed the results. Identification of the gases by portable probes showed that most of the tested samples emit mainly CO2. Toxic gases are emitted by four waste: metallic dust from the aluminum industry (CO), two air pollution control residue of industrial waste incinerator (H2S) and a halogenated solvent (organic volatile(s) compound(s)). HF has not been measured in these trials started before the present definition of HP 12. According to the definition of HP 12, only the H2S emission of substances with hazard statement EUH031 is accounted for. In view of the calcium content of the two air pollution control residue, the presence of calcium sulphide (EUH031) can be assumed. These two waste are therefore classified potentially hazardous for HP 12, from a total of 49 waste. They are also classified as hazardous for other properties (HP 7, 10and14 for one

  1. Electrophysiological Motor Unit Number Estimation (MUNE) Measuring Compound Muscle Action Potential (CMAP) in Mouse Hindlimb Muscles.

    PubMed

    Arnold, W David; Sheth, Kajri A; Wier, Christopher G; Kissel, John T; Burghes, Arthur H; Kolb, Stephen J

    2015-09-25

    Compound muscle action potential (CMAP) and motor unit number estimation (MUNE) are electrophysiological techniques that can be used to monitor the functional status of a motor unit pool in vivo. These measures can provide insight into the normal development and degeneration of the neuromuscular system. These measures have clear translational potential because they are routinely applied in diagnostic and clinical human studies. We present electrophysiological techniques similar to those employed in humans to allow recordings of mouse sciatic nerve function. The CMAP response represents the electrophysiological output from a muscle or group of muscles following supramaximal stimulation of a peripheral nerve. MUNE is an electrophysiological technique that is based on modifications of the CMAP response. MUNE is a calculated value that represents the estimated number of motor neurons or axons (motor control input) supplying the muscle or group of muscles being tested. We present methods for recording CMAP responses from the proximal leg muscles using surface recording electrodes following the stimulation of the sciatic nerve in mice. An incremental MUNE technique is described using submaximal stimuli to determine the average single motor unit potential (SMUP) size. MUNE is calculated by dividing the CMAP amplitude (peak-to-peak) by the SMUP amplitude (peak-to-peak). These electrophysiological techniques allow repeated measures in both neonatal and adult mice in such a manner that facilitates rapid analysis and data collection while reducing the number of animals required for experimental testing. Furthermore, these measures are similar to those recorded in human studies allowing more direct comparisons.

  2. A 5-HT3 receptor antagonist potentiates the behavioral, neurochemical and electrophysiological actions of an SSRI antidepressant.

    PubMed

    Bétry, C; Overstreet, D; Haddjeri, N; Pehrson, A L; Bundgaard, C; Sanchez, C; Mørk, A

    2015-04-01

    More effective treatments for major depression are needed. We studied if the selective 5-HT3 receptor antagonist ondansetron can potentiate the antidepressant potential of the selective serotonin (5-HT) reuptake inhibitor (SSRI) paroxetine using behavioral, neurochemical and electrophysiological methods. Flinders Sensitive Line (FSL) rats, treated with ondansetron, and/or a sub-effective dose of paroxetine, were assessed in the forced swim test. The effects of an acute intravenous administration of each compound alone and in combination were evaluated with respect to 5-HT neuronal firing rate in the dorsal raphe nucleus (DRN). Effects of s.c. administration of the compounds alone and in combination on extracellular levels of 5-HT were assessed in the ventral hippocampus of freely moving rats by microdialysis. The results showed that ondansetron enhanced the antidepressant activity of paroxetine in the forced swim test. It partially prevented the suppressant effect of paroxetine on DRN 5-HT neuronal firing and enhanced the paroxetine-induced increase of hippocampal extracellular 5-HT release. These findings indicate that 5-HT3 receptor blockade potentiates the antidepressant effects of SSRIs. Since both paroxetine and ondansetron are used clinically, it might be possible to validate this augmentation strategy in depressed patients.

  3. The novel KMO inhibitor CHDI-340246 leads to a restoration of electrophysiological alterations in mouse models of Huntington's disease.

    PubMed

    Beaumont, Vahri; Mrzljak, Ladislav; Dijkman, Ulrike; Freije, Robert; Heins, Mariette; Rassoulpour, Arash; Tombaugh, Geoffrey; Gelman, Simon; Bradaia, Amyaouch; Steidl, Esther; Gleyzes, Melanie; Heikkinen, Taneli; Lehtimäki, Kimmo; Puoliväli, Jukka; Kontkanen, Outi; Javier, Robyn M; Neagoe, Ioana; Deisemann, Heike; Winkler, Dirk; Ebneth, Andreas; Khetarpal, Vinod; Toledo-Sherman, Leticia; Dominguez, Celia; Park, Larry C; Munoz-Sanjuan, Ignacio

    2016-08-01

    Dysregulation of the kynurenine (Kyn) pathway has been associated with the progression of Huntington's disease (HD). In particular, elevated levels of the kynurenine metabolites 3-hydroxy kynurenine (3-OH-Kyn) and quinolinic acid (Quin), have been reported in the brains of HD patients as well as in rodent models of HD. The production of these metabolites is controlled by the activity of kynurenine mono-oxygenase (KMO), an enzyme which catalyzes the synthesis of 3-OH-Kyn from Kyn. In order to determine the role of KMO in the phenotype of mouse models of HD, we have developed a potent and selective KMO inhibitor termed CHDI-340246. We show that this compound, when administered orally to transgenic mouse models of HD, potently and dose-dependently modulates the Kyn pathway in peripheral tissues and in the central nervous system. The administration of CHDI-340246 leads to an inhibition of the formation of 3-OH-Kyn and Quin, and to an elevation of Kyn and Kynurenic acid (KynA) levels in brain tissues. We show that administration of CHDI-340246 or of Kyn and of KynA can restore several electrophysiological alterations in mouse models of HD, both acutely and after chronic administration. However, using a comprehensive panel of behavioral tests, we demonstrate that the chronic dosing of a selective KMO inhibitor does not significantly modify behavioral phenotypes or natural progression in mouse models of HD.

  4. Increased BDNF protein expression after ischemic or PKC epsilon preconditioning promotes electrophysiologic changes that lead to neuroprotection.

    PubMed

    Neumann, Jake T; Thompson, John W; Raval, Ami P; Cohan, Charles H; Koronowski, Kevin B; Perez-Pinzon, Miguel A

    2015-01-01

    Ischemic preconditioning (IPC) via protein kinase C epsilon (PKCɛ) activation induces neuroprotection against lethal ischemia. Brain-derived neurotrophic factor (BDNF) is a pro-survival signaling molecule that modulates synaptic plasticity and neurogenesis. Interestingly, BDNF mRNA expression increases after IPC. In this study, we investigated whether IPC or pharmacological preconditioning (PKCɛ activation) promoted BDNF-induced neuroprotection, if neuroprotection by IPC or PKCɛ activation altered neuronal excitability, and whether these changes were BDNF-mediated. We used both in vitro (hippocampal organotypic cultures and cortical neuronal-glial cocultures) and in vivo (acute hippocampal slices 48 hours after preconditioning) models of IPC or PKCɛ activation. BDNF protein expression increased 24 to 48 hours after preconditioning, where inhibition of the BDNF Trk receptors abolished neuroprotection against oxygen and glucose deprivation (OGD) in vitro. In addition, there was a significant decrease in neuronal firing frequency and increase in threshold potential 48 hours after preconditioning in vivo, where this threshold modulation was dependent on BDNF activation of Trk receptors in excitatory cortical neurons. In addition, 48 hours after PKCɛ activation in vivo, the onset of anoxic depolarization during OGD was significantly delayed in hippocampal slices. Overall, these results suggest that after IPC or PKCɛ activation, there are BDNF-dependent electrophysiologic modifications that lead to neuroprotection.

  5. Utilization of a New Intracranial Support Catheter as an Intermediate Aspiration Catheter in the Treatment of Acute Ischemic Stroke: Technical Report on Initial Experience

    PubMed Central

    Lozano, J. Diego; Massari, Francesco; Howk, Mary C; de Macedo Rodrigues, Katyucia; Brooks, Christopher; Perras, Mary; Rex, David E; Wakhloo, Ajay K; Kühn, Anna Luisa

    2016-01-01

    The endovascular management of acute ischemic stroke (AIS) due to emergency large vessel occlusion (ELVO) has become the standard of care after the recent publication of landmark randomized, controlled trials. Mechanical thrombectomy, in addition to intravenous thrombolysis (within 4.5 hours when eligible), is now part of the algorithm of the standard of care when treating AIS in patients with ELVO in the anterior circulation up to six hours after symptom onset. A newly introduced device, the Arc™ intracranial support catheter (Medtronic, Irvine, USA), is specifically designed for the introduction of neurointerventional devices into the cerebral vasculature and facilitates the delivery of microcatheters into smaller, more distal intracranial vessels. This technical report describes the use of the Arc™ intracranial support catheter in the setting of AIS. PMID:27382525