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Sample records for acute electrophysiological experiments

  1. Electrophysiologic monitoring in acute brain injury.

    PubMed

    Claassen, Jan; Vespa, Paul

    2014-12-01

    To determine the optimal use and indications of electroencephalography (EEG) in critical care management of acute brain injury (ABI). An electronic literature search was conducted for articles in English describing electrophysiological monitoring in ABI from January 1990 to August 2013. A total of 165 studies were included. EEG is a useful monitor for seizure and ischemia detection. There is a well-described role for EEG in convulsive status epilepticus and cardiac arrest (CA). Data suggest EEG should be considered in all patients with ABI and unexplained and persistent altered consciousness and in comatose intensive care unit (ICU) patients without an acute primary brain condition who have an unexplained impairment of mental status. There remain uncertainties about certain technical details, e.g., the minimum duration of EEG studies, the montage, and electrodes. Data obtained from both EEG and EP studies may help estimate prognosis in ABI patients, particularly following CA and traumatic brain injury. Data supporting these recommendations is sparse, and high quality studies are needed. EEG is used to monitor and detect seizures and ischemia in ICU patients and indications for EEG are clear for certain disease states, however, uncertainty remains on other applications. PMID:25208668

  2. Electrophysiological measures of acute cerebral ischaemia

    NASA Astrophysics Data System (ADS)

    Ferree, T. C.; Hwa, R. C.

    2005-09-01

    A method of EEG analysis is described which provides new insights into EEG pathology in cerebral ischaemia. The method is based on a variant of detrended fluctuation analysis (DFA), which reduces short (10 s) segments of spontaneous EEG time series to two dimensionless scaling exponents. The spatial variability of each exponent is expressed in terms of its statistical moments across EEG channels. Linear discriminant analysis combines the moments into concise indices, which distinguish normal and stroke groups remarkably well. On average over the scalp, stroke patients have larger fluctuations on the longest time scales. This is consistent with the notion of EEG slowing, but extends that notion to a wider range of time scales. The higher moments show that stroke patients have markedly reduced variability over the scalp. This contradicts the notion of a purely focal EEG scalp topography and argues instead for a highly distributed effect. In these indices, subacute patients appear further from normal than acute patients.

  3. Electrophysiology of Hypothalamic Magnocellular Neurons In vitro: A Rhythmic Drive in Organotypic Cultures and Acute Slices

    PubMed Central

    Israel, Jean-Marc; Oliet, Stéphane H.; Ciofi, Philippe

    2016-01-01

    Hypothalamic neurohormones are released in a pulsatile manner. The mechanisms of this pulsatility remain poorly understood and several hypotheses are available, depending upon the neuroendocrine system considered. Among these systems, hypothalamo-neurohypophyseal magnocellular neurons have been early-considered models, as they typically display an electrical activity consisting of bursts of action potentials that is optimal for the release of boluses of the neurohormones oxytocin and vasopressin. The cellular mechanisms underlying this bursting behavior have been studied in vitro, using either acute slices of the adult hypothalamus, or organotypic cultures of neonatal hypothalamic tissue. We have recently proposed, from experiments in organotypic cultures, that specific central pattern generator networks, upstream of magnocellular neurons, determine their bursting activity. Here, we have tested whether a similar hypothesis can be derived from in vitro experiments in acute slices of the adult hypothalamus. To this aim we have screened our electrophysiological recordings of the magnocellular neurons, previously obtained from acute slices, with an analysis of autocorrelation of action potentials to detect a rhythmic drive as we recently did for organotypic cultures. This confirmed that the bursting behavior of magnocellular neurons is governed by central pattern generator networks whose rhythmic drive, and thus probably integrity, is however less satisfactorily preserved in the acute slices from adult brains. PMID:27065780

  4. Acute electrophysiological responses of bradykinin-stimulated human fibroblasts.

    PubMed

    Estacion, M

    1991-05-01

    1. Acute responses to bradykinin in human dermal fibroblasts were studied at 20-24 degrees C using both the patch-clamp technique to monitor ion currents and Fura-2 fluorescence to monitor [Ca2+]i. 2. During subconfluent culture, human dermal fibroblasts can express a diversity of ion channels as described in the preceding paper. 3. When GTP (1 mM) was included in the pipette solution, two additional ion channel populations were transiently augmented in response to bradykinin stimulation. 4. The first is a component of outwardly rectifying current which reached maximal induction within 10-15 s after bradykinin addition (1 microM) and then decayed back to near baseline over 60 s. 5. Ion substitution experiments combined with tail current analysis indicate that the outward current is carried predominantly by K+. 6. Video imaging of single-cell Fura-2 fluorescence from both intact cells and patch-clamped cells showed temporal correlation of the K+ current modulation and the Ca2+ transients in response to bradykinin stimulation. 7. The calcium ionophore, ionomycin, caused both an increase in intracellular calcium and the augmentation of the outward K+ current. The amount of additional K+ current was correlated with [Ca2+]i levels and could be elicited even without the presence of GTP in the pipette. 8. Apamin, a blocker of Ca(2+)-activated K+ channels, inhibited (at 1 microM) the ionomycin-induced modulation of K+ current. 9. In addition, an inward current was transiently induced in response to bradykinin. This current was strictly dependent on the presence of GTP in the pipette solution. This current showed little voltage dependence, as evidenced by a linear current vs. voltage relation, and a reversal potential near but measurably more positive than 0 mV. 10. This current could be decoupled from the Ca2+ transient and be irreversibly induced by including GTP gamma S (100 microM) in the pipette solution. 11. Ion substitution experiments show that this is a non

  5. The Automation of Electrophysiological Experiments and Data Analysis

    NASA Astrophysics Data System (ADS)

    Morton, David L.

    The role of computation in science is continually growing and neuroscience is no exception. Despite this, a severe lack of scientific software infrastructure persists, slowing progress in many domains. In this thesis, we will see how the combination of neuroscience and software engineering can build infrastructure that enables discovery. The first chapter discusses the Turtle Electrophysiology Project, or TEP, an experiment-automation and data-management system. This system has allowed us to automate away some of the most tedious tasks involved in conducting experiments. As a result, we can collect more data in less time, and with fewer errors related to the loss of metadata (information about how the data were collected). Also, since all of the metadata is automatically digitized during the experiment we can now completely automate our analyses. Chapters two and three are examples of research conducted using the ever-evolving TEP system. In the first instance, we used TEP to deliver visual stimuli and handle data-management. In chapter three, the experiments involved delivering electrical stimuli instead of visual stimuli, and much more rigorous analysis. And even though TEP was not specifically designed to handle collecting data this way, the flexible tags system enabled us to do so. Finally, chapter four details the construction of a robust analysis tool called Spikepy. Whereas TEP is specially designed for the turtle preparation we have, Spikepy is a general-purpose spike-sorting application and framework. Spikepy takes flexibility to the extreme by being a plugin-based framework, yet maintaining a very easy to use interface.

  6. The contribution of electrophysiology to knowledge of the acute and chronic effects of ethanol.

    PubMed

    Little, H J

    1999-12-01

    This review describes the effects of ethanol on the components of neuronal transmission and the relationship of such effects to the behavioural actions of ethanol. The concentrations of ethanol with acute actions on voltage-sensitive ion channels are first described, then the actions of ethanol on ligand-gated ion channels, including those controlled by cholinergic receptors, 5-hydroxytryptamine receptors, the various excitatory amino acid receptors, and gamma-aminobutyric acid receptors. Acute effects of ethanol are then described on brain areas thought to be involved in arousal and attention, the reinforcing effects of ethanol, the production of euphoria, the actions of ethanol on motor control, and the amnesic effects of ethanol; the acute effects of ethanol demonstrated by EEG studies are also discussed. Chronic effects of alcohol on neuronal transmission are described in the context of the various components of the ethanol withdrawal syndrome, withdrawal hyperexcitability, dysphoria and anhedonia, withdrawal anxiety, craving, and relapse drinking. Electrophysiological studies on the genetic influences on the effects of ethanol are discussed, particularly the acute actions of ethanol and electrophysiological differences reported in individuals predisposed to alcoholism. The conclusion notes the concentration of studies on the classical transmitters, with relative neglect of the effects of ethanol on peptides and on neuronal interactions between brain areas and integrated patterns of neuronal activity. PMID:10665833

  7. 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.

  8. 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

  9. Interventional Electrophysiology in Children: A Single-Center Experience

    PubMed Central

    Mosaed, Pasha; Dalili, Mohammad; Emkanjoo, Zahra

    2012-01-01

    Objective Ablation techniques of cardiac arrhythmia in children have significantly progressed in the past decade; however, the number of pediatric ablations is still significantly lower than that in adults. Accordingly, there is less information regarding the success rate and complications in this age group. Methods All pediatric ablations conducted between March 2005 and February 2011 at Rajaie Heart Center were studied. Abolishing the arrhythmia source by the end of procedure was considered as success. Recurrences before hospital discharge and those thereafter were named early recurrence and late recurrence, respectively. Findings A total of 125 catheter ablations were performed for 112 patients. Of them 118 (94.4%) procedures were successful. The success rate was significantly higher in the patients with atrioventricular nodal reentry tachycardia (AVNRT). Of 105 patients who continued follow-up program, 7 (6.7%) cases experienced recurrence; the recurrence rate was inversely dependent on the patients’ body size (P-value <0.05). There was no mortality. Five cases were complicated during or early after the procedure, all the complications were cured completely. Conclusion Therapeutic electrophysiology in children is an effective and relatively low-risk method. The recurrence and complication rates are similar to those reported in adults. Considering our results and the previous reports, pediatric patients with serious arrhythmia should not be deprived from ablation and should not be exposed to long-term toxic drugs. PMID:23399953

  10. Effects of acute ozone exposure on the electrophysiological properties of guinea pig trachea

    SciTech Connect

    Croxton, T.L.; Takahashi, Masahiko; Kokia, Ira

    1994-12-31

    Acute ozone (O{sub 3}) exposures produce an increase in the apparent permeability of the tracheal epithelium, but the mechanism of this response is poorly understood. Comparison of previous studies suggests that qualitative differences may exist between measurements made in vivo or in vitro. To test this possibility we used both in vitro and in vivo electrophysiological techniques to investigate the effects of O{sub 3} exposure on guinea pig tracheal epithelium. Male Hartley guinea pigs were exposed to either 1 or 2 ppm O{sub 3} or to filtered air for 3 h and were studied 0, 6, or 24 h after exposure. Air-exposed animals had in vitro mean tracheal potential (V{sub T}) -32.0 {+-} 1.5 mV, conductance (G{sub T}{sup L}) 2.18 {+-} 0.22 mS/cm, short-circuit current (I{sub SC}{sup L}) 62.6 {+-} 3.7 {mu}A/cm, and diameter (D) 2.44 {+-} 0.10 mm. In vitro properties after 1 ppm O{sub 3} exposure did not differ at any time point from control. Two parts per million O{sub 3} increased I{sub SC}{sup L}, but only at 6 h postexposure. The effect of O{sub 3} on I{sub SC}{sup L} was abolished by amiloride. There were no significant changes in V{sub T}, G{sub T}{sup L}, or D. In vivo tracheal potential under pentobarbital anesthesia was -19.7 {+-} 1.7 mV. At 6 h postexposure to 2 ppm O{sub 3}, but not at 0 or 24 h, in vivo V{sub I} was increased. Thus, acute exposure of guinea pigs to a high concentration of O{sub 3} caused a delayed increase in Na{sup +} absorption by the trachea with no change in conductance. This indicates that paracellular permeability of guinea pig tracheal epithelium was not substantially increased by acute O{sub 3} and suggests that enhanced macromolecular uptake in this species probably occurs transcellularly. 24 refs., 1 fig., 2 tabs.

  11. Sampling methods for exploring between-subject variability in cardiac electrophysiology experiments.

    PubMed

    Drovandi, C C; Cusimano, N; Psaltis, S; Lawson, B A J; Pettitt, A N; Burrage, P; Burrage, K

    2016-08-01

    Between-subject and within-subject variability is ubiquitous in biology and physiology, and understanding and dealing with this is one of the biggest challenges in medicine. At the same time, it is difficult to investigate this variability by experiments alone. A recent modelling and simulation approach, known as population of models (POM), allows this exploration to take place by building a mathematical model consisting of multiple parameter sets calibrated against experimental data. However, finding such sets within a high-dimensional parameter space of complex electrophysiological models is computationally challenging. By placing the POM approach within a statistical framework, we develop a novel and efficient algorithm based on sequential Monte Carlo (SMC). We compare the SMC approach with Latin hypercube sampling (LHS), a method commonly adopted in the literature for obtaining the POM, in terms of efficiency and output variability in the presence of a drug block through an in-depth investigation via the Beeler-Reuter cardiac electrophysiological model. We show improved efficiency for SMC that produces similar responses to LHS when making out-of-sample predictions in the presence of a simulated drug block. Finally, we show the performance of our approach on a complex atrial electrophysiological model, namely the Courtemanche-Ramirez-Nattel model. PMID:27512137

  12. 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. PMID:20559707

  13. Reverse Translation of Clinical Electrophysiological Biomarkers in Behaving Rodents under Acute and Chronic NMDA Receptor Antagonism

    PubMed Central

    Sullivan, Elyse M; Timi, Patricia; Hong, L Elliot; O'Donnell, Patricio

    2015-01-01

    Electroencephalogram (EEG) stands out as a highly translational tool for psychiatric research, yet rodent and human EEG are not typically obtained in the same way. In this study we developed a tool to record skull EEG in awake-behaving rats in a similar manner to how human EEG are obtained and then used this technique to test whether acute NMDA receptor antagonism alters rodent EEG signals in a similar manner as in humans. Acute MK-801 treatment elevated gamma power and reduced beta band power, which closely mirrored EEG data from healthy volunteers receiving acute ketamine. To explore the mechanisms behind these oscillatory changes, we examined the effects of GABA-A receptor blockade, finding that picrotoxin (PTX) recapitulated the decrease in sound-evoked beta oscillations observed with acute MK-801, but did not produce changes in gamma band power. Chronic treatment with either PTX or MK-801 did not affect frequency-specific oscillatory activity when tested 24 h after the last drug injection, but decreased total broadband oscillatory power. Overall, this study validated a novel platform for recording rodent EEG and demonstrated similar oscillatory changes after acute NMDA receptor antagonism in both humans and rodents, suggesting that skull EEG may be a powerful tool for further translational studies. PMID:25176166

  14. Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

    PubMed Central

    Rouach, Nathalie

    2012-01-01

    Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents. PMID:23222635

  15. Mapping multidimensional pain experience onto electrophysiological responses to noxious laser heat stimuli.

    PubMed

    Stancak, Andrej; Cook, Stephanie; Wright, Hazel; Fallon, Nicholas

    2016-01-15

    The origin of the conscious experience of pain in the brain is a continuing enigma in neuroscience. To shed light on the brain representation of a multifaceted pain experience in humans, we combined multivariate analysis of subjective aspects of pain sensations with detailed, single-trial analysis of electrophysiological brain responses. Participants were asked to fully focus on any painful or non-painful sensations occurring in their left hand during an interval surrounding the onset of noxious laser heat stimuli, and to rate their sensations using a set of visual analogue scales. Statistical parametric mapping was used to compute a multivariate regression analysis of subjective responses and single-trial laser evoked potentials (LEPs) at subject and group levels. Standardized Low Resolution Electromagnetic Tomography method was used to reconstruct sources of LEPs. Factor analysis of subjective responses yielded five factors. Factor 1, representing pain, mapped firstly as a negative potential at the vertex and a positive potential at the fronto-temporal region during the 208-260ms interval, and secondly as a strong negative potential in the right lateral frontal and prefrontal scalp regions during the 1292-1340ms interval. Three other factors, labelled "anticipated pain", "stimulus onset time", and "body sensations", represented non-specific aspects of the pain experience, and explained portions of LEPs in the latency range from 200ms to 700ms. The subjective space of pain during noxious laser stimulation is represented by one large factor featuring pain intensity, and by other factors accounting for non-specific parts of the sensory experience. Pain is encoded in two separate latency components with different scalp and brain representations. PMID:26477652

  16. Effect of acute doses of controlled-release carbamazepine on clinical, psychomotor, electrophysiological, and cognitive parameters of brain function.

    PubMed

    van der Meyden, C H; Bartel, P R; Sommers, D K; Blom, M; Becker, P; Erasmus, S; Griesel, D

    1992-01-01

    The neurotoxic effect of acute doses of carbamazepine controlled-release (CBZ-CR) divitabs (800, 1,200, and 1,600 mg) was assessed on clinical, psychomotor, electrophysiological, and cognitive parameters of brain function in 10 healthy volunteers in a double-blind, randomised, placebo-controlled, phase I study. Significant changes compared to placebo were demonstrated for the clinical scales, ataxia (AT), convergence of the near-point (CNP), peak saccadic velocity (PSV), critical flicker fusion (CFF), spectral analysis of the EEG, and brainstem auditory evoked potential (BAEP) tests. Digit repetition, digit symbol substitution, Sternberg memory scanning time, Sternberg choice reaction time, saccadic latency, and saccadic accuracy showed important negative findings. Significant clinical tolerance to side effects developed within 20 to 33 h after CBZ-CR dosage during a period in which the mean CBZ blood levels remained virtually unchanged. CBZ-CR, 800, 1,200, and 1,600 mg yielded low, medium, and high therapeutic blood levels, respectively, for +10 to +33 h after dosage without the development of severe clinical side effects. PMID:1547763

  17. Towards A Smart Experimental Arena for Long-Term Electrophysiology Experiments

    PubMed Central

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

    2011-01-01

    Advancements in wireless power and data transmission have raised the prospects of using a variety of low power microelectronic devices such as biosensors, stimulators, and actuators in long-term uninterrupted electrophysiology experiments on small freely behaving animal subjects in large experimental arenas. This paper presents our progress towards developing such a system, called the EnerCage. This system includes a stationary unit for inductive power transmission through a scalable array of overlapping hexagonal coils, which are optimized using an accurate inductive link model and an iterative optimization process. Furthermore, the EnerCage system is equipped with an array of 3-D magnetic sensors and a smart tracking algorithm for non-line-of-sight positioning of the animal subject. EnerCage also has a small mobile unit, which is either attached to or implanted in the subject’s body. This unit includes a magnetic tracer and an efficient power management block, which is capable of closed-loop regulated inductive power delivery to the experimental device(s) of interest. An early prototype of the EnerCage system with six coils has been presented here. The coil array achieves a power efficiency of 17.8% at the worst-case horizontal misalignment of 42 mm (half of the coil radius) at a coupling distance of 70 mm with the mobile unit coil of 20 mm in radius. PMID:23853228

  18. Electrophysiological properties and chemosensitivity of acutely dissociated trigeminal somata innervating the cornea.

    PubMed

    Veiga Moreira, T H; Gover, T D; Weinreich, D

    2007-09-01

    Adult rat sensory trigeminal ganglion neurons innervating the cornea (cTGNs) were isolated and identified following retrograde dye labeling with FM1-43. Using standard whole-cell patch clamp recording techniques, cTGNs could be subdivided by their action potential (AP) duration. Fast cTGNs had AP durations <1 ms (40%) while slow cTGNs had AP durations >1 ms and an inflection on the repolarization phase of the AP. With the exception of membrane input resistance, the passive membrane properties of fast cTGNs were different from those of slow cTGNs (capacitance: 61+/-4.5 pF vs. 42+/-2.6 pF, resting membrane potential: -59+/-0.7 mV vs. -53+/-0.9 mV, for fast and slow cTGNs respectively). Active membrane properties also differed between fast and slow cTGNs. Slow cTGNs had a higher AP threshold (-25+/-1.6 mV vs. -38+/-0.8 mV), a larger rheobase (14+/-1.9 pA/pF vs. 6.8+/-1.0 pA/pF), and a smaller AP undershoot (-56+/-1.7 mV vs. -67+/-2.5 mV). The AP overshoot, however was similar between the two types of neurons (46+/-3.1 mV vs. 48+/-4 mV). Slow cTGNs were depolarized by capsaicin (1 microM, 80%) and 60% of their APs were blocked by tetrodotoxin (TTX) (100 nM). Fast cTGNs were unaffected by capsaicin and 100% of their APs were blocked by TTX. Similarly, cTGNs were also heterogeneous with respect to their responses to exogenous ATP and 5-HT. The current work shows that cTGNs have distinctive electrophysiological properties and chemosensitivity profiles. These characteristics may mirror the distinct properties of corneal sensory nerve terminals. The availability of isolated identified cTGNs constitutes a tractable model system to investigate the biophysical and pharmacological properties of corneal sensory nerve terminals. PMID:17706884

  19. Electrophysiological study of infant and adult rats under acute intoxication with fluoroacetamide.

    PubMed

    Kuznetsov, Sergey V; Jenkins, Richard O; Goncharov, Nikolay V

    2007-01-01

    A study was conducted of acute intoxication of infant and adult Wistar rats with fluoroacetamide (FAA), an inhibitor of oxidative metabolism. FAA was administered orally to adult rats at 1/2 LD(50) and subcutaneously to infant rats at LD(100) or 1/10 LD(50). Electrocardiogram (ECG), respiration and motor activity were registered for 7 days. Clinical analysis of ECG and the heart rate variability (HRV) was carried out to assess the state of the vegetative nervous system. In adult rats, FAA caused marked disturbances in the activity of cardiovascular and respiratory systems, including the development of a potentially lethal acute cor pulmonale. Conversely, there were no significant changes of cardiac function and respiration in infant rats; they died because of extreme emaciation accompanied by retardation of development. In adult rats, bursts of associated cardiac and respiratory tachyarrhythmia, as well as regular high amplitude spasmodic sighs having a deca-second rhythm were observed. In both infant and adult rats, FAA caused short-term enhancement of humoral (metabolic) and sympathetic activities, followed by a gradual and stable predominance of parasympathetic influence on HRV. Under conditions of FAA inhibition of the tricarboxylic acid cycle, the observed physiological reactions may be explained by activation of alternative metabolic pathways. This is also supported by a lack of ontogenetically caused inhibition of spontaneous motor activity in infant rats poisoned with FAA, which highlights the significance of the alternative metabolic pathways for implementation of deca-second and minute rhythms and a lack of a rigid dependence of these rhythms upon activity of neuronal networks. PMID:17351914

  20. 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%). PMID:23853228

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

    NASA Astrophysics Data System (ADS)

    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.

  2. [Family experiences post-acute myocardial infarction].

    PubMed

    Garcia, Raquel Pötter; Budó, Maria de Lourdes Denardin; Simon, Bruna Sodré; Wünsch, Simone; Oliveira, Stefanie Griebeler; Barbosa, Mariane da Silva

    2013-09-01

    This study aimed to describe the family experiences post-infarction. Qualitative, descriptive and exploratory research, carried out with six families of post-infarction patients. Data collection was conducted in families' homes, in the period of February to May of 2012, through observation and interviews with the family. The software Atlas Ti 6.2 was used to code the interviews and the data were explored with thematic analysis. Two categories emerged "Difficult times": immediate consequence of acute myocardial infarction for the families; and "We reeducate ourselves--we can adapt ourselves": current experience of families. The immediate post-infarction experience is permeated by several feelings, with the need for families to adapt to fit into the needs. The current experience shows changes in families due to the disease. The family is the main responsible for the care giving, although Nursing should exchange and share knowledge. PMID:24344600

  3. [An oneiroid experience during severe acute polyradiculoneuritis].

    PubMed

    Wegener, K; Tassan, P; Josse, M O; Bolgert, F

    1995-02-01

    This study is to present a psychopathological analysis of complex hallucinatory symptoms--without consciousness breaking up in confusional state--occurring in patients with acute Guillain-Barré's syndrome diagnosis requiring neurological intensive care. Finally the patients experience an unitary and closed situation "close to dream without being dream". This experience is corresponding to the semeiology of the "oneiroid experience" (Mayer-Gross, 1924). The "oneiroid experience" appears to be of syndromic nature independent of any etiological and/or nosological classification. But its conceptualization does probably need widening: the oneiroid world appears to be a creation of a primitive function which inserts us in the world before any science or verification. PMID:7741405

  4. 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

  5. Acute and chronic exposure to ethanol and the electrophysiology of the brush border membrane of rat small intestine.

    PubMed Central

    al-Balool, F; Debnam, E S; Mazzanti, R

    1989-01-01

    In this study we have investigated the effects of (a) chronic ethanol intake on glucose and galactose absorption across the rat jejunum in vivo and on the potential difference across the isolated brush border membrane (Vm) and (b) acute exposure to ethanol (4% or 8%) and acetaldehyde (0.25%) on changes in Vm associated with Na(+)-dependent galactose absorption across the jejunum and ileum. Chronic ethanol intake was associated with hyperpolarization of Vm and an enhanced galactose but not glucose transport. Acute ethanol and acetaldehyde were without effect on Vm whether or not galactose was present. We conclude that while a greater electrochemical gradient across the brush border membrane is a likely explanation for the stimulation of galactose absorption induced by ethanol feeding, factors other than changes in Vm are responsible for the inhibitory effects of acute ethanol. PMID:2612984

  6. Language experience shapes early electrophysiological responses to visual stimuli: the effects of writing system, stimulus length, and presentation duration.

    PubMed

    Xue, Gui; Jiang, Ting; Chen, Chuansheng; Dong, Qi

    2008-02-15

    How language experience affects visual word recognition has been a topic of intense interest. Using event-related potentials (ERPs), the present study compared the early electrophysiological responses (i.e., N1) to familiar and unfamiliar writings under different conditions. Thirteen native Chinese speakers (with English as their second language) were recruited to passively view four types of scripts: Chinese (familiar logographic writings), English (familiar alphabetic writings), Korean Hangul (unfamiliar logographic writings), and Tibetan (unfamiliar alphabetic writings). Stimuli also differed in lexicality (words vs. non-words, for familiar writings only), length (characters/letters vs. words), and presentation duration (100 ms vs. 750 ms). We found no significant differences between words and non-words, and the effect of language experience (familiar vs. unfamiliar) was significantly modulated by stimulus length and writing system, and to a less degree, by presentation duration. That is, the language experience effect (i.e., a stronger N1 response to familiar writings than to unfamiliar writings) was significant only for alphabetic letters, but not for alphabetic and logographic words. The difference between Chinese characters and unfamiliar logographic characters was significant under the condition of short presentation duration, but not under the condition of long presentation duration. Long stimuli elicited a stronger N1 response than did short stimuli, but this effect was significantly attenuated for familiar writings. These results suggest that N1 response might not reliably differentiate familiar and unfamiliar writings. More importantly, our results suggest that N1 is modulated by visual, linguistic, and task factors, which has important implications for the visual expertise hypothesis. PMID:18053744

  7. Electrophysiological evidence of personal experiences in the great Sichuan earthquake impacting on selective attention.

    PubMed

    Qiu, Jiang; Li, Hong; Zhang, QingLin; Huang, LiHui; Guo, YaQiao; Tu, Shen; Wang, Ting; Wei, DongTao

    2009-07-01

    Event-related brain potentials (ERPs) were measured when 24 Chinese subjects performed the earthquake color-matching Stroop task. All of them have experienced the great Sichuan earthquake (5.12), with 12 subjects in each of Chengdu city and Chongqing city (different earthquake experiences) groups. The behavioral data showed that the earthquake Stroop task yielded robust the earthquake interference effect as indexed by longer RT for earthquake-related (Related) words than earthquake-unrelated (Unrelated) words only in the Chengdu group. Scalp ERP analysis also revealed the neurophysiological substrate of the interference effect: a greater positivity (P350-450) in Related words as compared to Unrelated words was found between 350 and 450 ms post-stimulus over fronto-central scalp regions in the Chengdu group, while the interference effect was not found in the Chongqing group. The P350-450 might reflect an earthquake experience interference, but also attention enhancing, effect of earthquake-related words. Dipole source analysis of the difference wave (Related-Unrelated) showed that a generator was localized in the parahippocampal gyrus, which was possibly associated with flashbulb memory (personal earthquake experience). The results indicated that different personal earthquake experiences might be critical in engaging the neural mechanisms that underlie the modulation of selective attention. PMID:19641874

  8. 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

  9. "Reality" of near-death-experience memories: evidence from a psychodynamic and electrophysiological integrated study.

    PubMed

    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

  10. 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

  11. When Early Experiences Build a Wall to Others’ Emotions: An Electrophysiological and Autonomic Study

    PubMed Central

    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. PMID:23593374

  12. Acute chest pain emergencies - spouses' prehospital experiences.

    PubMed

    Forslund, Kerstin; Quell, Robin; Sørlie, Venke

    2008-10-01

    The call to the Emergency Medical Dispatch Centre is often a person's first contact with the health-care system in cases of acute illness or injury and acute chest pain is a common reason for calling. The aim was to illuminate how spouses to persons with acute chest pain experienced the alarm situation, the emergency call and the prehospital emergency care. Interviews were conducted with nineteen spouses. A phenomenological-hermeneutic approach was used for the analyses. The themes responsibility and uneasiness emerged as well as an overall theme of aloneness. Being a spouse to a person in need of acute medical and nursing assistance was interpreted as "Being responsible and trying to preserve life" and "Being able to manage the uneasiness and having trust in an uncertain situation." When their partners' life was at risk the spouses were in an escalating spiral of worry, uncertainty, stress, fear of loss, feeling of loneliness and desperation. They had to manage emotional distress and felt compelled to act to preserve life, a challenging situation. PMID:18929341

  13. 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

  14. Improving patients' and staff's experiences of acute care.

    PubMed

    Chaplin, Rob; Crawshaw, Jacob; Hood, Chloe

    2015-03-01

    The aim of this audit was to assess the effect of the Quality Mark programme on the quality of acute care received by older patients by comparing the experiences of staff and older adults before and after the programme. Data from 31 wards in 12 acute hospitals were collected over two stages. Patients and staff completed questionnaires on the perceived quality of care on the ward. Patients rated improved experiences of nutrition, staff availability and dignity. Staff received an increase in training and reported better access to support, increased time and skill to deliver care and improved morale, leadership and teamwork. Problems remained with ward comfort and mealtimes. Overall, results indicated an improvement in ratings of care quality in most domains during Quality Mark data collection. Further audits need to explore ways of improving ward comfort and mealtime experience. PMID:25727634

  15. Imaging modalities in cardiac electrophysiology.

    PubMed

    Hasan, Reema; Clifford, Sarah M; Ghanbari, Hamid; Schmidt, Martin; Segerson, Nathan M; Daccarett, Marcos

    2010-01-01

    Cardiac imaging, both noninvasive and invasive, has become a crucial part of evaluating patients during the electrophysiology procedure experience. These anatomical data allow electrophysiologists to not only assess who is an appropriate candidate for each procedure, but also to determine the rate of success from these procedures. This article incorporates a review of the various cardiac imaging techniques available today, with a focus on atrial arrhythmias, ventricular arrhythmias and device therapy. PMID:20014991

  16. Experiences of the advanced nurse practitioner role in acute care.

    PubMed

    Cowley, Alison; Cooper, Joanne; Goldberg, Sarah

    2016-05-01

    The aim of the service evaluation presented in this article was to explore the multidisciplinary team's (MDT) experiences and perception of the advanced nurse practitioner (ANP) role on an acute health care of the older person ward. A qualitative case study was carried out comprising semi-structured interviews with members of the MDT, exploring their experiences of the ANP role. An overarching theme of 'Is it a nurse? Is it a doctor? No, it's an ANP' emerged from the data, with three subthemes: the missing link; facilitating and leading holistic care; and safe, high quality care. The ANP role is valued by the MDT working with them and provides a unique skill set that has the potential to enhance care of older patients living with frailty. While there are challenges to its introduction, it is a role worth introducing to older people's wards. PMID:27125941

  17. 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.

  18. “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

  19. Historical perspectives of cardiac electrophysiology.

    PubMed

    Lüderitz, Berndt

    2009-01-01

    The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From earliest times, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favored these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequently arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts: it may also provide the observer with a chronological vantage point from which to view the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories. PMID:19196616

  20. An electrophysiological study of the intermediate syndrome of organophosphate poisoning.

    PubMed

    Lorenzoni, Paulo José; Gasparetto, Juliano; Kay, Cláudia Suemi Kamoi; Scola, Rosana Herminia; Werneck, Lineu César

    2010-09-01

    Acute organophosphate (OP) poisoning is commonly seen in emergency medicine. Neurologists must be alert to detect neuromuscular transmission failure and other neurological complications that follow OP poisoning. We report a 37-year-old male with acute OP poisoning to emphasize the electrophysiological abnormalities during the intermediate syndrome (IMS). Motor nerve conduction studies revealed that a single nerve stimulation evoked a repetitive compound muscle action potential, whereas repetitive nerve stimulation resulted in a combination of a decrement-increment pattern and a repetitive fade response. Thus, electrophysiological studies can be used to monitor patients with IMS, and these test results correlate well with clinical findings in acute OP poisoning. PMID:20483619

  1. The Benefit of a General, Systematic Use of Mapping Systems During Electrophysiological Procedures in Children and Teenagers: The Experience of an Adult EP Laboratory.

    PubMed

    Marini, Massimiliano; Del Greco, Maurizio; Ravanelli, Daniele; Cima, Anna; Coser, Alessio; Porcedda, Giulio; Guarracini, Fabrizio; Valentini, Aldo; Bonmassari, Roberto

    2016-04-01

    Standard imaging during electrophysiological procedures (EPs) uses fluoroscopy. The aim of this study was to evaluate the feasibility, efficacy, safety and effect of an extended use of non-fluoroscopic mapping systems (NMSs) for imaging during paediatric EPs in an adult EP laboratory focusing on the amount of X-ray exposure. This study is a retrospective analysis that includes consecutive young patients (83 pts, aged between 8 and 18) who underwent EPs from March 2005 to February 2015. We compare the fluoroscopy data of two groups of pts: Group I, pts who underwent EPs from 2005 to 2008 using only fluoroscopy and Group II, pts who underwent EPs from 2008 to 2015 performed also using NMSs. The use of an NMS resulted in reduced fluoroscopy time in Group II {median value 0.1 min (95 % CI [0.00-1.07])} compared to Group I {median value 3.55 min (95 % CI [1.93-7.83]) (MW test, P < 0.05)}. There was a complementary reduction in the total X-ray exposure from 2.53 Gy cm(2) (95 % CI [1.51-4.66]) in Group I to 0.05 Gy cm(2) in Group II (95 % CI [0.00-1.22]) (MW test, P < 0.05). Regarding ablation procedures, the median effective dose decreased from 3.04 mSv (95 % CI [1.22-6.89]) to 0.25 mSv (95 % CI [0.00-0.60]) (MW test, P < 0.05). The use of an NMS dramatically reduces fluoroscopy time and total X-ray exposure during EPs in children and teenagers in an adult EP laboratory. In our experience, this reduction is mainly related to the systematic day-to-day use of NMSs. PMID:26932365

  2. Electrophysiological Endophenotypes for Schizophrenia.

    PubMed

    Owens, Emily M; 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 GABAergic inhibition in the pathophysiology of schizophrenia. We conclude that refining the measurement of electrophysiological endophenotypes, expanding genetic association studies, and integrating data sets are important next steps for understanding the mechanisms that connect identified genetic risk loci for schizophrenia to the disease phenotype. PMID:26954597

  3. Advances in Electrophysiological Research.

    PubMed

    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

  4. 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

  5. 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

  6. [Research of the visual electrophysiology record system based on DSP].

    PubMed

    Xiong, Kai; Hou, Min-Xian; Ye, Guan-Rong

    2005-03-01

    An application of digital signal processor (DSP) in the visual electrophysiology record system is presented in this paper. The system's design and implementation are described in detail. Results of its simulation and the clinical experiments are acceptable. PMID:16011113

  7. Acute Mediastinitis in Children: A Nine-Year Experience

    PubMed Central

    Mirshemirani, Alireza; Rouzrokh, Mohsen; Mohajerzadeh, Laili; Tabari, Nasibeh Khaleghnejad; Ghaffari, Parand

    2013-01-01

    Background Acute mediastinitis is a serious medical condition with a mortality rate of 30 to 40% or even higher. Early diagnosis with prompt and aggressive treatment is essential to prevent its rapid progression. We evaluated acute mediastinitis cases and analyzed the outcomes. Materials and Methods A retrospective chart review was conducted on patients diagnosed with acute mediastinitis who were admitted to Mofid Children's Hospital from January 2001 to January 2010. Results Seventeen patients aged 1 to 10 yrs. (mean =3.8 yrs) were evaluated including 12 (70%) boys and 5 (30%) girls. The most common symptoms were fever, dyspnea, cyanosis, tachycardia and tachypnea. The etiology of mediastinitis was iatrogenic esophageal perforation (EP), and related to manipulation in 13(77%), and leakage of esophageal anastomosis in 4 cases (33%). The underlying diseases were esophageal atresia in 2(12%), corrosive injury of the esophagus in 13(76%), congenital esophageal stenosis in one (6%), and gastroesophageal reflux esophagitis also in one (6%) patient. Patients with clinical symptoms were evaluated by immediate chest radiography, and gastrografin swallow. After early diagnosis, the patients received wide spectrum antibiotics and immediate mediastinal or thoracic drainage, followed by esophagostomy and gastrostomy. Only one case of endoscopic perforation was managed by NG tube. Fifteen patients (88%) survived successfully. We had 2(12%) cases of mortality in our study (one patient after esophageal substitution, mediastinal abscess and septicemia, and the other one developed esophageal perforation 6 months after early management and died of cardiac arrest during endoscopic dilation). Conclusion Prevention of acute mediastinitis is still a difficult challenge. As the prognosis is not good and patients have high mortality, rapid management is mandatory. PMID:25191462

  8. The Cardiac Electrophysiology Web Lab.

    PubMed

    Cooper, Jonathan; Scharm, Martin; Mirams, Gary R

    2016-01-19

    Computational modeling of cardiac cellular electrophysiology has a long history, and many models are now available for different species, cell types, and experimental preparations. This success brings with it a challenge: how do we assess and compare the underlying hypotheses and emergent behaviors so that we can choose a model as a suitable basis for a new study or to characterize how a particular model behaves in different scenarios? We have created an online resource for the characterization and comparison of electrophysiological cell models in a wide range of experimental scenarios. The details of the mathematical model (quantitative assumptions and hypotheses formulated as ordinary differential equations) are separated from the experimental protocol being simulated. Each model and protocol is then encoded in computer-readable formats. A simulation tool runs virtual experiments on models encoded in CellML, and a website (https://chaste.cs.ox.ac.uk/WebLab) provides a friendly interface, allowing users to store and compare results. The system currently contains a sample of 36 models and 23 protocols, including current-voltage curve generation, action potential properties under steady pacing at different rates, restitution properties, block of particular channels, and hypo-/hyperkalemia. This resource is publicly available, open source, and free, and we invite the community to use it and become involved in future developments. Investigators interested in comparing competing hypotheses using models can make a more informed decision, and those developing new models can upload them for easy evaluation under the existing protocols, and even add their own protocols. PMID:26789753

  9. 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

  10. Electrophysiology of Axonal Constrictions

    NASA Astrophysics Data System (ADS)

    Johnson, Christopher; Jung, Peter; Brown, Anthony

    2013-03-01

    Axons of myelinated neurons are constricted at the nodes of Ranvier, where they are directly exposed to the extracellular space and where the vast majority of the ion channels are located. These constrictions are generated by local regulation of the kinetics of neurofilaments the most important cytoskeletal elements of the axon. In this paper we discuss how this shape affects the electrophysiological function of the neuron. Specifically, although the nodes are short (about 1 μm) in comparison to the distance between nodes (hundreds of μm) they have a substantial influence on the conduction velocity of neurons. We show through computational modeling that nodal constrictions (all other features such as numbers of ion channels left constant) reduce the required fiber diameter for a given target conduction velocity by up to 50% in comparison to an unconstricted axon. We further show that the predicted optimal fiber morphologies closely match reported fiber morphologies. Supported by The National Science Foundation (IOS 1146789)

  11. Electrophysiological recording from a 'model' cell.

    PubMed

    Zhang, Bing; Stewart, Bryan

    2010-09-01

    The Drosophila larval neuromuscular junction (NMJ) shares many structural and functional similarities to synapses in other animals, including humans. These include the basic feature of synaptic transmission, as well as the molecular mechanisms regulating the synaptic vesicle cycle. Because of its large size, easy accessibility, and the well-characterized genetics, the fly NMJ remains an excellent model system for dissecting the cellular and molecular mechanisms of synaptic transmission. This protocol describes the basics of setting up and conducting electrophysiological experiments using a model cell. For the novice, a model cell provides a way to learn the operation of electrophysiology equipment and software without the anxiety of damaging living cells. This protocol also illustrates passive membrane properties such as the input resistance, capacitance, and time constant. PMID:20810633

  12. Experience based co-design reduces formal complaints on an acute mental health ward

    PubMed Central

    Springham, Neil; Robert, Glenn

    2015-01-01

    An acute mental health triage ward at Oxleas NHS Foundation Trust was attracting high levels of formal service user and family complaints. The Trust used experience based co-design to examine the issues and redesign procedures. This resulted in an immediate eradication of formal complaints for a period of 23 months. This paper describes two outcomes: firstly, the successful adaptations made to the experience based co-design methodology from its origins in physical care, in order to ensure it was safe and effective in an acute mental health setting; and, secondly, the changes made to the ward as a result of this quality improvement intervention. PMID:26734433

  13. Past and future aspects of clinical electrophysiology.

    PubMed

    Lüderitz, Berndt

    2008-01-01

    The diagnosis and treatment of clinical electrophysiology has a long and fascinating history. From the earliest time, no clinical symptom impressed the patient (and the physician) more than an irregular heart beat. Although ancient Chinese pulse theory laid the foundation for the study of arrhythmias and clinical electrophysiology in the 5th century BC, the most significant breakthrough in the identification and treatment of cardiac arrhythmias first occurred in this century. In the last decades, our knowledge of electrophysiology and pharmacology has increased exponentially. The enormous clinical significance of cardiac rhythm disturbances has favoured these advances. On the one hand, patients live longer and thus are more likely to experience arrhythmias. On the other hand, circulatory problems of the cardiac vessels have increased enormously, and this has been identified as the primary cause of cardiac rhythm disorders. Coronary heart disease has become not just the most significant disease of all, based on the statistics for cause of death. Arrhythmias are the main complication of ischemic heart disease, and they have been directly linked to the frequent arrhythmogenic sudden death syndrome, which is now presumed to be an avoidable "electrical accident" of the heart. A retrospective look--often charming in its own right--may not only make it easier to sort through the copious details of this field and so become oriented in this universe of important and less important facts; it may also assist the observer in a chronological vantage point of the subject. The study of clinical electrophysiology is no dry compendium of facts and figures, but rather a dynamic field of study evolving out of the competition between various ideas, intentions and theories. PMID:18651426

  14. Children's Electrophysiological Responses to Music.

    ERIC Educational Resources Information Center

    Flohr, John W.; And Others

    This study examined the electrophysiological differences between baseline EEG frequencies and EEG frequencies obtained while listening to music stimuli. The experimental group comprised 22 children, ages 4 to 6 years old, who received special music instruction twice a week for 25 minutes for 7 weeks. The control group received no music…

  15. [Sudden death. Role of the electrophysiologic study].

    PubMed

    Colín Lizalde, Luis

    2002-01-01

    At present, sudden death is considered a major health problem, DeBoer in 1935, recognized the clinical importance of ventricular fibrillation as the cause of sudden cardiac death. Sudden death due to cardiovascular problems has been established as one of the main causes of death in the developed countries and in developing countries as ours, where the deaths caused by cardiovascular diseases represent 15% of the total, exceeding other causes of death. The frequency of sudden death in our country is unknown, but more frequently we hear about cases of patients that have been reanimated for cardiac arrest; in the United States of America the frequency has been estimated between 400,000 at 500,000 per year although, recently, 250,000 at 300,000 events are being mentioned. It is convenient to comment that the causal arrhythmias are diverse and may vary depending on the underlying disease, although, generally, it can be pointed out that 80% of them are due to tachyarrhythmias. It's important to point out that there is a strong relationship between left ventricular dysfunction, the frequency of ventricular arrhythmias, and fatal cardiac events due to cardiac rhythm disturbances. The recommendations for electrophysiological studies are: 1) patients surviving cardiac arrest, occurring without evidence of an acute Q-wave myocardial infarction and 2) patients surviving cardiac arrest occurring more than 48 hours after the acute phase of myocardial infarction in the absence of a recurrent ischemic event. PMID:12001869

  16. Electrophysiology of raccoon cuneocerebellar neurons.

    PubMed

    Haring, J H; Rowinski, M J; Pubols, B H

    1984-01-01

    Electrophysiological experiments were undertaken in order to locate and functionally characterize cells of the raccoon main cuneate nucleus (MCN) that can be activated by electrical stimulation of the cerebellum. A total of 98 such units were studied in pentobarbital sodium-anesthetized, methoxyflurane-anesthetized, or decerebrate preparations. Aside from a greater likelihood of resting discharge in the decerebrate preparations, no appreciable variability in physiological properties of the neurons could be attributed to differences in the type of preparation. Using constant latency of response and ability to be blocked by collision as principal criteria, both antidromically (n = 31) and synaptically (n = 67) activated neurons of the main cuneate nucleus could be identified. A small number of MCN neurons could be activated by both cerebellar and thalamic stimulation, but no unit was antidromically activated from both locations. MCN neurons projecting to the cerebellum are located primarily in the ventral polymorphic cell region of the nucleus at and rostral to the obex, corresponding to the "medial tongue" region of Johnson et al. (1968). In contrast, neurons synaptically activated from the cerebellum are found throughout the dorsoventral extent of the rostral MCN, including the "clusters" region. The majority of antidromically activated units responded to mechanical stimulation of deeper tissues, and most of these were activated by muscle stretch. Only a small portion (13-15%) of either antidromically or synaptically activated units were classed as light touch units with peripheral receptive fields (RFs) restricted to glabrous surfaces of the forepaw. Glabrous skin RFs located on the digital surfaces are smaller than those located on the palm pads. In both cases, RFs are larger than those associated with primary afferent fibers, but toward the low end of the distribution for MCN neurons not activated by cerebellar stimulation. All MCN units activated by cerebellar

  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) PMID:1462070

  18. 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

  19. [Characteristics of general anesthesia in the investigation of heart electrophysiology].

    PubMed

    Narbutas, Kestutis; Lekas, Raimundas; Rimkiene, Aldona; Civinskiene, Genuvaite

    2002-01-01

    Investigating electrophysiological properties of the heart under acute experimental conditions, dogs are affected by operative stress because of traumatic surgical manipulations, so investigations are performed under general anaesthesia. Many anaesthetics together with their main function have desintegrating influence on autonomic regulation mechanisms. That is why anaesthetics used during experiments must fullfil such requirement--have minimal influence on autonomic nervous system (ANS) and heart conductivity system (HCS) interaction parameters or to make this influence insignificant. We did not found common anaesthesia methodics that can fullfil that requirements, so we decided to prepare new common anaesthesia methodics, which could fullfil requirements mentioned above. We choose medicaments according to their pharmacokinetics and pharmacodynamics action. For methodics optimization we've used 2 groups of dogs (mongrel dogs males weight 7-15 kg) (n = 10). We've applied different anaesthesia schemas on each group. Premedication in the I-st group was performed with intramuscle (i.m.) combination of diazepam, ketamine and phentanyl and for anaesthesia continuous intravenous (i.v.) infusion of thiopental and ketamine. In II-nd group premedication was performed with i.m. injection of ketamine/phentanyl combination and for anaesthesia--continuous i.v. infusion of thiopental. Induction in both groups was performed with i.v. thiopental injection. Suitability of premedication and anaesthesia was valued by adequativity of haemodynamics (heart rate 1/min) and surgical manipulations during experiments. Our conclusion is: investigating interaction of ANS and HCS methodics used in the I-st group of dogs is more suitable. PMID:12474758

  20. The lived experience of new graduate nurses working in an acute care setting.

    PubMed

    McCalla-Graham, James A; De Gagne, Jennie C

    2015-03-01

    The high attrition rate of graduate nurses will exacerbate the current nursing shortage as Baby Boomer nurses (born between 1946 and 1964) retire, negatively affecting the quality of patient care and increasing employer costs. The purpose of this phenomenological study was to explore the lived experiences of new graduate nurses employed in an acute care setting in southwest Florida. This information provides further guidance to nurse educators as they develop curricula, support graduate nurses to transition into professional practice, and create strategies to increase retention. Ten participants who were traditional students in generic baccalaureate nursing programs, selected through purposeful and snowball sampling, were interviewed via open-ended questions. Using Colaizzi's classic phenomenological method of data analysis and NVivo 10 software, three over-arching themes emerged-knowledge, skills, and environment-which were interpreted in relation to graduates' lived experience. Recommendations include implementation of innovative initiatives that address new graduates' experience and increase retention. PMID:25723333

  1. Baccalaureate nursing students' experience of dyadic learning in an acute care setting.

    PubMed

    Trueman, Gregg; Osuji, Joseph; El-Hussein, Mohamed Toufic

    2014-09-01

    This article describes a unique learning project designed to address the praxis gap between baccalaureate nursing students' clinical learning and theoretic principles of collaborative practice on an acute medical-surgical unit in Canada. The study was framed by the active engagement model to provide second-year nursing students a nontraditional approach to develop their nursing practice. Clinical faculty partnered with medical-surgical nursing staff and eight baccalaureate nursing students to explore the experience of collaborative learning and stakeholders' anticipated learning outcomes while working in dyads. A modified phenomenological approach was used in understanding the experience of dyadic learning through reflective journals, course evaluation data, and a semistructured exit interview for analysis. Four themes were revealed based on students' reflection of their experience: work engagement, relational practice, autonomy, and empowerment. These themes underscore the strengths and opportunities associated with this nontraditional approach to clinical learning. PMID:25199158

  2. Experiences with Capnography in Acute Care Settings: A Mixed-Methods Analysis of Clinical Staff

    PubMed Central

    Langhan, Melissa L.; Kurtz, Jordan C.; Schaeffer, Paula; Asnes, Andrea G.; Riera, Antonio

    2014-01-01

    Purpose While capnography is being incorporated into clinical guidelines, it is not used to it's full potential. We investigated reasons for limited implementation of capnography in acute care areas and explored facilitators and barriers to its implementation. Methods A purposeful sample of physicians and nurses in emergency departments (ED) and intensive care units (ICU) participated in semistructured interviews. Grounded theory, iterative data analysis and the constant comparative method were used to analyze the data to inductively generate ideas and build theories. Results Nineteen providers were interviewed from five hospitals. Six themes were identified: variability in use of capnography among acute care units, availability and accessibility of capnography equipment, the evidence behind capnography use, the impact of capnography on patient care, personal experiences impacting use of capnography, and variable knowledge about capnography. Barriers and facilitators to use were found within each theme. Conclusions We observed varied responsiveness to capnography and identified factors that work to foster or discourage its use. This data can guide future implementation strategies. A deliberate strategy to foster utilization, mitigate barriers and broadly accelerate implementation has the potential to profoundly impact use of capnography in acute care areas with the goal of improving patient care. PMID:25129575

  3. Evaluation of Fibrogenic Potential of Industrial Multi-Walled Carbon Nanotubes in Acute Aspiration Experiment

    PubMed Central

    Khaliullin, T. O.; Shvedova, A. A.; Kisin, E. R.; Zalyalov, R. R.; Fatkhutdinova, L. M.

    2015-01-01

    Local inflammatory response in the lungs and fibrogenic potential of multi-walled carbon nanotubes were studied in an acute aspiration experiment in mice. The doses were chosen based on the concentration of nanotubes in the air at a workplace of the company-producer. ELISA, flow cytometry, enhanced darkfield microscopy, and histological examination showed that multi-walled carbon nanotubes induced local inflammation, oxidative stress, and connective tissue growth (fibrosis). Serum levels of TGF-β1 and osteopontin proteins can serve as potential exposure biomarkers. PMID:25778660

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

    PubMed Central

    Radcliffe, Jonathan; Bird, Laura

    2016-01-01

    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. PMID:27512586

  5. 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. PMID:27512586

  6. Redox artifacts in electrophysiological recordings

    PubMed Central

    Berman, Jonathan M.

    2013-01-01

    Electrophysiological techniques make use of Ag/AgCl electrodes that are in direct contact with cells or bath. In the bath, electrodes are exposed to numerous experimental conditions and chemical reagents that can modify electrode voltage. We examined voltage offsets created in Ag/AgCl electrodes by exposure to redox reagents used in electrophysiological studies. Voltage offsets were measured in reference to an electrode separated from the solution by an agar bridge. The reducing reagents Tris-2-carboxyethly-phosphine, dithiothreitol (DTT), and glutathione, as well as the oxidizing agent H2O2 used at experimentally relevant concentrations reacted with Ag in the electrodes to produce voltage offsets. Chloride ions and strong acids and bases produced offsets at millimolar concentrations. Electrolytic depletion of the AgCl layer, to replicate voltage clamp and sustained use, resulted in increased sensitivity to flow and DTT. Offsets were sensitive to electrode silver purity and to the amount and method of chloride deposition. For example, exposure to 10 μM DTT produced a voltage offset between 10 and 284 mV depending on the chloride deposition method. Currents generated by these offsets are significant and dependent on membrane conductance and by extension the expression of ion channels and may therefore appear to be biological in origin. These data demonstrate a new source of artifacts in electrophysiological recordings that can affect measurements obtained from a variety of experimental techniques from patch clamp to two-electrode voltage clamp. PMID:23344161

  7. Electrophysiological study of auditory development.

    PubMed

    Lippé, S; Martinez-Montes, E; Arcand, C; Lassonde, M

    2009-12-15

    Cortical auditory evoked potential (CAEP) testing, a non-invasive technique, is widely employed to study auditory brain development. The aim of this study was to investigate the development of the auditory electrophysiological signal without addressing specific abilities such as speech or music discrimination. We were interested in the temporal and spectral domains of conventional auditory evoked potentials. We analyzed cerebral responses to auditory stimulation (broadband noises) in 40 infants and children (1 month to 5 years 6 months) and 10 adults using high-density electrophysiological recording. We hypothesized that the adult auditory response has precursors that can be identified in infant and child responses. Results confirm that complex adult CAEP responses and spectral activity patterns appear after 5 years, showing decreased involvement of lower frequencies and increased involvement of higher frequencies. In addition, time-locked response to stimulus and event-related spectral pertubation across frequencies revealed alpha and beta band contributions to the CAEP of infants and toddlers before mutation to the beta and gamma band activity of the adult response. A detailed analysis of electrophysiological responses to a perceptual stimulation revealed general development patterns and developmental precursors of the adult response. PMID:19665050

  8. 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. PMID:22154954

  9. 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. PMID:25352538

  10. Biofeedback in psychomotor training. Electrophysiological basis.

    PubMed

    Bazanova, O M; Mernaya, E M; Shtark, M B

    2009-06-01

    The influences of individual musical practice and the same practice supplemented with biofeedback using electrophysiological markers for optimum music-performing activity were studied in 39 music students. Traditional technical practice produced increases in integral EMG power and decreases in alpha activity in most of the students with initially low maximum alpha activity peak frequencies. Similar practice but combined with individual sessions of alpha-EEG/EMG biofeedback were accompanied by increases in the frequency, bandwidth, and activation responses of EEG alpha rhythms in all subjects, along with decreases in EEG integral power. The efficacy of training with biofeedback and the ability to experience psychomotor learning depended on the initial individual characteristics of EEG alpha activity. PMID:19430974

  11. 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

  12. 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. PMID:27298766

  13. Pediatric & Congenital Electrophysiology Society: building an international paediatric electrophysiology organisation.

    PubMed

    Cohen, Mitchell; Sanatani, Shubhayan; Stephenson, Elizabeth; Skinner, Jon; Drago, Fabrizio; Davis, Andrew; Janousek, Jan; Rosenthal, Eric; Collins, Kathryn K; Triedman, John

    2016-05-01

    The Pediatric and Congenital Electrophysiology Society (PACES) is a non-profit organisation comprised of individuals dedicated to improving the care of children and young adults with cardiac rhythm disturbances. Although PACES is a predominantly North American-centric organisation, international members have been a part of PACES for the last two decades. This year, PACES expanded its North American framework into a broadly expansive international role. On May 12, 2015, paediatric electrophysiology leaders from within the United States of America and Canada met with over 30 international paediatric electrophysiologists from 17 countries and five continents discussing measures to (1) expand PACES' global vision, (2) address ongoing challenges such as limited resource allocation that may be present in developing countries, (3) expand PACES' governance to include international representation, (4) promote joint international sessions at future paediatric EP meetings, and (5) facilitate a global multi-centre research consortium. This meeting marked the inception of a formal international collaborative spirit in PACES. This editorial addresses some solutions to breakdown the continental silos paediatric electrophysiologists have practiced within; however, there remain ongoing limitations, and future discussions will be needed to continue to move the PACES global international vision forward. PMID:27090729

  14. Pediatric & Congenital Electrophysiology Society: building an international paediatric electrophysiology organisation.

    PubMed

    Cohen, Mitchell; Sanatani, Shubhayan; Stephenson, Elizabeth; Skinner, Jon; Drago, Fabrizio; Davis, Andrew; Janousek, Jan; Rosenthal, Eric; Collins, Kathryn K; Triedman, John

    2016-08-01

    The Pediatric and Congenital Electrophysiology Society (PACES) is a non-profit organisation comprised of individuals dedicated to improving the care of children and young adults with cardiac rhythm disturbances. Although PACES is a predominantly North American-centric organisation, international members have been a part of PACES for the last two decades. This year, PACES expanded its North American framework into a broadly expansive international role. On 12 May, 2015, paediatric electrophysiology leaders from within the United States of America and Canada met with over 30 international paediatric electrophysiologists from 17 countries and five continents discussing measures to (1) expand PACES' global vision, (2) address ongoing challenges such as limited resource allocation that may be present in developing countries, (3) expand PACES' governance to include international representation, (4) promote joint international sessions at future paediatric EP meetings, and (5) facilitate a global multi-centre research consortium. This meeting marked the inception of a formal international collaborative spirit in PACES. This editorial addresses some solutions to breakdown the continental silos paediatric electrophysiologists have practiced within; however, there remain ongoing limitations, and future discussions will be needed to continue to move the PACES global international vision forward. PMID:27075202

  15. Electrophysiological evidence for phenomenal consciousness.

    PubMed

    Revonsuo, Antti; Koivisto, Mika

    2010-09-01

    Abstract Recent evidence from event-related brain potentials (ERPs) lends support to two central theses in Lamme's theory. The earliest ERP correlate of visual consciousness appears over posterior visual cortex around 100-200 ms after stimulus onset. Its scalp topography and time window are consistent with recurrent processing in the visual cortex. This electrophysiological correlate of visual consciousness is mostly independent of later ERPs reflecting selective attention and working memory functions. Overall, the ERP evidence supports the view that phenomenal consciousness of a visual stimulus emerges earlier than access consciousness, and that attention and awareness are served by distinct neural processes. PMID:24168341

  16. 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.

  17. 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.

  18. Initial Management of Childhood Acute Immune Thrombocytopenia: Single-Center Experience of 32 Years.

    PubMed

    Yildiz, Inci; Ozdemir, Nihal; Celkan, Tiraje; Soylu, Selen; Karaman, Serap; Canbolat, Aylin; Dogru, Omer; Erginoz, Ethem; Apak, Hilmi

    2015-01-01

    Immune thrombocytopenia (ITP) is an acute self-limited disease of childhood, mostly resolving within 6 months irrespective of whether therapy is given or not. Treatment options when indicated include corticosteroids, intravenous immune globulin (IVIG), and anti-RhD immunoglobulin. We reviewed our 32 years' experience for first-line therapy of acute ITP. Five hundred forty-one children (mean age: 5.3 years) diagnosed and treated for ITP were evaluated retrospectively. Among 491 acute ITP patients, IVIG was used in 27%, high-dose steroids in 27%, low-dose steroids in 20%, anti-D immunoglobulin G (IgG) in 2%, and no therapy in 22%. When the initial response (platelets >50 × 10(9)/L) to first-line treatment modalities were compared, 89%, 84%, and 78% patients treated by low-dose steroids, high-dose steroids, and IVIG responded to treatment, respectively (P > .05). Mean time to recovery of platelets was 16.8, 3.8, and 3.0 days in patients treated with low-dose steroids, high-dose steroids, and IVIG, respectively (P < .0001). Thrombocytopenia recurred in 23% of low-dose steroid, 39% of high-dose steroid, and in 36% of IVIG (P < .0001) treatment groups. Of 108 patients who were observed alone, 4 (3%) had a recurrence on follow-up and only 2 of these required treatment subsequently. Recurrence was significantly less in no therapy group compared with children treated with 1 of the 3 options of pharmacotherapy (P < .0001). Response rates were similar between patients treated by IVIG and low- and high-dose steroids; however, time to response was slower in patients treated with low-dose steroids compared with IVIG and high-dose steroids. PMID:26154620

  19. A silicon based implantable microelectrode array for electrophysiological and dopamine recording from cortex to striatum in the non-human primate brain.

    PubMed

    Zhang, Song; Song, Yilin; Wang, Mixia; Zhang, Zhiming; Fan, Xinyi; Song, Xianteng; Zhuang, Ping; Yue, Feng; Chan, Piu; Cai, Xinxia

    2016-11-15

    Dual-mode, multielectrode recordings have become routine in rodent neuroscience research and have recently been adapted to the non-human primate. However, robust and reliable application of acute, multielectrode recording methods in monkeys especially for deep brain nucleus research remains a challenge. In this paper, We described a low cost silicon based 16-site implantable microelectrode array (MEA) chip fabricated by standard lithography technology for in vivo test. The array was 25mm long and designed to use in non-human primate models, for electrophysiological and electrochemical recording. We presented a detailed protocol for array fabrication, then showed that the device can record Spikes, LFPs and dopamine (DA) variation continuously from cortex to striatum in an esthetized monkey. Though our experiment, high-quality electrophysiological signals were obtained from the animal. Across any given microelectrode, spike amplitudes ranged from 70 to 300μV peak to peak, with a mean signal-to-noise ratio of better than 5:1. Calibration results showed the MEA probe had high sensitivity and good selectivity for DA. The DA concentration changed from 42.8 to 481.6μM when the MEA probe inserted from cortex into deep brain nucleus of striatum, which reflected the inhomogeneous distribution of DA in brains. Compared with existing methods allowing single mode (electrophysiology or electrochemistry) recording. This system is designed explicitly for dual-mode recording to meet the challenges of recording in non-human primates. PMID:27155116

  20. [Electrophysiologic study in arrhythmia surgery].

    PubMed

    Nitta, Takashi

    2007-07-01

    The traditional paradigm in surgery for cardiac arrhythmias has been the electrophysiological assessment of the arrhythmia followed by the determination of a specific lesion set for the ablation or a definitive procedure based on the results of the analysis in each patient. The maze procedure was developed as a definitive procedure for atrial fibrillation (AF) and was not guided by electrophysiologic findings in individual patients. The rationale behind the maze procedure is to create a line of conduction block to prevent the propagation of repetitive activations from the pulmonary veins toward the left atrium and to block the reentrant activations occurring on the atrial wall. The cut-and-sew technique is the most reliable method to accomplish conduction block. However, it extends the cardiac arrest and cardiopulmonary times and increases the risk of bleeding. During the past decade, a number of ablation devices have been developed and tested in animals and humans for their ability to create complete conduction block. The use of ablation devices enables less invasive AF surgery. However, the non-transmural or non-contiguous necrosis caused by an incomplete ablation can permit conduction across the ablation line and impair the efficacy of the surgery. Intraoperative verification of conduction block is mandatory to assure the transmurality and contiguity of the lesions created by the ablation devices. PMID:17763669

  1. Acute epiglottitis in a rural area: experiences with an anesthesiologist-staffed ambulance helicopter.

    PubMed

    Søreide, E; Smedvig, J P; Harboe, S; Mikkelsen, H; Eielsen, O V

    1994-01-01

    The majority of fatalities due to acute epiglottitis (AE) result from prehospital airway problems. We reviewed the courses of 14 patients with AE treated by an aeromedical team consisting of an anesthesiologist and a paramedic. Eight patients were transported from a physician's office or from the patient's own home. One patient was intubated at the scene, and two received ventilatory support with mask and bag en route to the hospital. Two patients suffered cardiopulmonary arrest before arrival of the aeromedical team, both resulting in severe hypoxic encephalopathy. All six patients transported from hospitals were intubated prior to the helicopter transport. Based on our own experience and a review of the literature, we discuss prehospital airway management in this group of patients. PMID:8207158

  2. 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. PMID:12605952

  3. 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

  4. Breadboard Amplifier: Building and Using Simple Electrophysiology Equipment.

    PubMed

    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

  5. [Towards optical in vivo electrophysiology].

    PubMed

    Lambot, Laurie; Gall, David

    Optical imaging of voltage indicators is a promising approach for detecting the activity of neuronal circuits with high spatial and temporal resolution. In this context, genetically encoded voltage indicators, combining genetic targeting and optical readout of transmembrane voltage, represent a technological breaktrough that will without doubt have a major impact in neuroscience. However, so far the existing genetically encoded voltage indicators lacked the capabilities to detect individual action potentials and fast spike trains in live animals. Here, we present a novel indicator allowing high-fidelity imaging of individual spikes and dentritic voltage dynamics in vivo. Used in combination with optogenetics, which allows to manipulate neuronal activity, this opens the possibility of an all-optical electrophysiology. PMID:27615186

  6. Electrophysiological investigation of toxic neuropathies.

    PubMed

    Le Quesne, P M

    1982-01-01

    Electrophysiological changes are correlated with pathological processes. Marked slowing of conduction is found in segmental demyelination due to delayed nodal excitation or short lengths of continuous conduction. Secondary demyelination causes slow conduction in hexacarbon neuropathy. Slight reduction in maximal conduction velocity is attributable to selective damage to large fibres in acrylamide neuropathy. Sensory nerve action potential amplitude is a sensitive measure of peripheral nerve function and comparison of abnormalities in different nerve segments may indicate the nature of the underlying pathological change. Other abnormalities may be elucidated by double stimuli; eg repetitive activity due to cholinesterase inhibition only occurs after the first of two closely spaced stimuli. Activity-related excitability changes may be detected by measuring the amplitude of the response to a submaximal stimulus at varying times after a maximal shock and is increased and prolonged by the pyrethroid deltamethrin. PMID:6962658

  7. 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.

  8. 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

    2016-01-01

    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. PMID:27480786

  9. 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. PMID:27429525

  10. Estrogen Receptor Beta and 2-arachidonoylglycerol Mediate the Suppressive Effects of Estradiol on Frequency of Postsynaptic Currents in Gonadotropin-Releasing Hormone Neurons of Metestrous Mice: An Acute Slice Electrophysiological Study

    PubMed Central

    Bálint, Flóra; Liposits, Zsolt; Farkas, Imre

    2016-01-01

    Gonadotropin-releasing hormone (GnRH) neurons are controlled by 17β-estradiol (E2) contributing to the steroid feedback regulation of the reproductive axis. In rodents, E2 exerts a negative feedback effect upon GnRH neurons throughout the estrus-diestrus phase of the ovarian cycle. The present study was undertaken to reveal the role of estrogen receptor subtypes in the mediation of the E2 signal and elucidate the downstream molecular machinery of suppression. The effect of E2 administration at low physiological concentration (10 pM) on GnRH neurons in acute brain slices obtained from metestrous GnRH-green fluorescent protein (GFP) mice was studied under paradigms of blocking or activating estrogen receptor subtypes and interfering with retrograde 2-arachidonoylglycerol (2-AG) signaling. Whole-cell patch clamp recordings revealed that E2 significantly diminished the frequency of spontaneous postsynaptic currents (sPSCs) in GnRH neurons (49.62 ± 7.6%) which effect was abolished by application of the estrogen receptor (ER) α/β blocker Faslodex (1 μM). Pretreatment of the brain slices with cannabinoid receptor type 1 (CB1) inverse agonist AM251 (1 μM) and intracellularly applied endocannabinoid synthesis blocker THL (10 μM) significantly attenuated the effect of E2 on the sPSCs. E2 remained effective in the presence of tetrodotoxin (TTX) indicating a direct action of E2 on GnRH cells. The ERβ specific agonist DPN (10 pM) also significantly decreased the frequency of miniature postsynaptic currents (mPSCs) in GnRH neurons. In addition, the suppressive effect of E2 was completely blocked by the selective ERβ antagonist PHTPP (1 μM) indicating that ERβ is required for the observed rapid effect of the E2. In contrast, the ERα agonist PPT (10 pM) or the membrane-associated G protein-coupled estrogen receptor (GPR30) agonist G1 (10 pM) had no significant effect on the frequency of mPSCs in these neurons. AM251 and tetrahydrolipstatin (THL) significantly abolished

  11. 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

    2016-01-01

    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

  12. 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

  13. 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. PMID:24972014

  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

    2015-01-01

    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

  15. 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

  16. 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

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

    PubMed

    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

  18. 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

  19. Working memory of emotional stimuli: Electrophysiological characterization.

    PubMed

    Kessel, Dominique; García-Rubio, María J; González, E Kirstin; Tapia, Manuel; López-Martín, Sara; Román, Francisco J; Capilla, Almudena; Martínez, Kenia; Colom, Roberto; Carretié, Luis

    2016-09-01

    Memorizing emotional stimuli in a preferential way seems to be one of the adaptive strategies brought on by evolution for supporting survival. However, there is a lack of electrophysiological evidence on this bias in working memory. The present study analyzed the influence of emotion on the updating component of working memory. Behavioral and electrophysiological indices were measured from a 3-back task using negative, neutral, and positive faces. Electrophysiological data evidenced an emotional influence on the working memory sensitive P3 component, which presented larger amplitudes for negative matching faces compared to neutral ones. This effect originated in the superior parietal cortex, previously reported to be involved in N-back tasks. Additionally, P3 results showed a correlation with reaction times, where higher amplitudes were associated with faster responses for negative matching faces. These findings indicate that electrophysiological measures seem to be very suitable indices of the emotional influence on working memory. PMID:27402441

  20. Evaluation of negative pressure vacuum-assisted system in acute and chronic wounds closure: our experience.

    PubMed

    Chiummariello, S; Guarro, G; Pica, A; Alfano, C

    2012-10-01

    Negative-pressure therapy or vacuum-assisted closure (VAC) has been used in clinical applications since the 1940's and has increased in popularity over the past decade. This dressing technique consists of an open cell foam dressing put into the wound cavity, a vacuum pump produces a negative pressure and an adhesive drape. A controlled sub atmospheric pressure from 75 to 150 mmHg is applied. The vacuum-assisted closure has been applied by many clinicians to chronic wounds in humans; however it cannot be used as a replacement for surgical debridement. The initial treatment for every contaminated wound should be the necrosectomy. The VAC therapy has a complementary function and the range of its indications includes pressure sores, stasis ulcers, chronic wounds such as diabetic foot ulcers, post traumatic and post operative wounds, infected wounds such as necrotizing fasciitis or sternal wounds, soft-tissue injuries, bone exposed injuries, abdominal open wounds and for securing a skin graft. We describe our experience with the VAC dressing used to manage acute and chronic wounds in a series of 135 patients, with excellent results together with satisfaction of the patients. PMID:23095568

  1. 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'…

  2. The electrophysiological development of cardiomyocytes.

    PubMed

    Liu, Jie; Laksman, Zachary; Backx, Peter H

    2016-01-15

    The generation of human cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) has become an important resource for modeling human cardiac disease and for drug screening, and also holds significant potential for cardiac regeneration. Many challenges remain to be overcome however, before innovation in this field can translate into a change in the morbidity and mortality associated with heart disease. Of particular importance for the future application of this technology is an improved understanding of the electrophysiologic characteristics of CMs, so that better protocols can be developed and optimized for generating hPSC-CMs. Many different cell culture protocols are currently utilized to generate CMs from hPSCs and all appear to yield relatively “developmentally” immature CMs with highly heterogeneous electrical properties. These hPSC-CMs are characterized by spontaneous beating at highly variable rates with a broad range of depolarization-repolarization patterns, suggestive of mixed populations containing atrial, ventricular and nodal cells. Many recent studies have attempted to introduce approaches to promote maturation and to create cells with specific functional properties. In this review, we summarize the studies in which the electrical properties of CMs derived from stem cells have been examined. In order to place this information in a useful context, we also review the electrical properties of CMs as they transition from the developing embryo to the adult human heart. The signal pathways involved in the regulation of ion channel expression during development are also briefly considered. PMID:26788696

  3. The digital hearing aid, wearable computing, and electrophysiological response.

    PubMed

    Doyle, T E; Kucerovsky, Z; Greason, W D

    2002-01-01

    Presbycusis is the most common form of hearing loss caused by aging and long-term exposure to sound energy. This type of ailment decreases the ear's ability to perceive high frequencies and localize sound, thus making comprehension more difficult. To compensate for this loss, the choice of a digital hearing aid has become more common. However, most digital hearing aids do little more that their analogue predecessor's by providing a single, fixed hearing response. Such a fixed response is not suitable for all of a user's auditory environments and typically causes a more rapid loss of hearing. Significant advancement in processing power and reduction in size of computing hardware has produced increasingly more powerful, more portable, and more personal computing devices. These advances have spurred research and development of wearable computing devices towards integrating both man and machine. By definition, the digital hearing aid is a wearable computing device. The development of a digital hearing aid with increased onboard processing that is aware of its owner's electrophysiological and auditory environments is an obvious progression. This awareness will give the hearing aid the ability to autonomously modify its own parameters to improve audibility and comprehension. Electrophysiological signals can be classified as naturally occurring or voluntarily controlled. Employing these signals will allow the hearing aid to adapt to its owner's external and internal stimuli. Research and initial experiments into the monitoring and use of electrophysiological response for the control of the digital hearing aid shall be presented. PMID:12085589

  4. Fibroblast KATP currents modulate myocyte electrophysiology in infarcted hearts.

    PubMed

    Benamer, Najate; Vasquez, Carolina; Mahoney, Vanessa M; Steinhardt, Maximilian J; Coetzee, William A; Morley, Gregory E

    2013-05-01

    Cardiac metabolism remains altered for an extended period of time after myocardial infarction. Studies have shown fibroblasts from normal hearts express KATP channels in culture. It is unknown whether fibroblasts from infarcted hearts express KATP channels and whether these channels contribute to scar and border zone electrophysiology. KATP channel subunit expression levels were determined in fibroblasts isolated from normal hearts (Fb), and scar (sMI-Fb) and remote (rMI-Fb) regions of left anterior descending coronary artery (LAD) ligated rat hearts. Whole cell KATP current density was determined with patch clamp. Action potential duration (APD) was measured with optical mapping in myocyte-only cultures and heterocellular cultures with fibroblasts with and without 100 μmol/l pinacidil. Whole heart optical mapping was used to assess KATP channel activity following LAD ligation. Pinacidil activated a potassium current (35.4 ± 7.5 pA/pF at 50 mV) in sMI-Fb that was inhibited with 10 μmol/l glibenclamide. Kir6.2 and SUR2 transcript levels were elevated in sMI-Fb. Treatment with Kir6.2 short interfering RNA decreased KATP currents (87%) in sMI-Fb. Treatment with pinacidil decreased APD (26%) in co-cultures with sMI-Fb. APD values were prolonged in LAD ligated hearts after perfusion with glibenclamide. KATP channels are present in fibroblasts from the scar and border zones of infarcted hearts. Activation of fibroblast KATP channels could modulate the electrophysiological substrate beyond the acute ischemic event. Targeting fibroblast KATP channels could represent a novel therapeutic approach to modify border zone electrophysiology after cardiac injury. PMID:23436329

  5. Electrophysiological Correlates of Emotional Responding in Schizophrenia

    PubMed Central

    Horan, William P.; Wynn, Jonathan K.; Kring, Ann M.; Simons, Robert F.; Green, Michael F.

    2010-01-01

    People with schizophrenia consistently report normal levels of pleasant emotion when exposed to evocative stimuli, suggesting intact consummatory pleasure. However, little is known about the neural correlates and time course of emotion in schizophrenia. This study used a well-validated affective picture viewing task that elicits a characteristic pattern of Event Related Potentials (ERP) from early to later processing stages (i.e., P1, P2, P3, and Late Positive Potentials (LPP)). Thirty eight stabilized schizophrenia outpatients and 36 healthy controls viewed standardized pleasant, unpleasant, and neural pictures while ERPs were recorded, and subsequently rated their emotional responses to the stimuli. Patients and controls responded to the pictures similarly in terms of their valence ratings, as well as the initial ERP components (P1, P2, and P3). However, at the later LPP component (500 – 1000 ms), patients displayed diminished electrophysiological discrimination between pleasant versus neutral stimuli. This pattern suggests that patients demonstrate normal self-reported emotional experience and intact initial sensory processing of and resource allocation to emotional stimuli. However, they show a disruption in a later component associated with sustained attentional processing of emotional stimuli. PMID:20141239

  6. Integrated platform and API for electrophysiological data.

    PubMed

    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

  7. 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

  8. IRAD experience on surgical type A acute dissection patients: results and predictors of mortality

    PubMed Central

    Berretta, Paolo; Patel, Himanshu J.; Gleason, Thomas G.; Sundt, Thoralf M.; Myrmel, Truls; Desai, Nimesh; Korach, Amit; Panza, Antonello; Bavaria, Joe; Khoynezhad, Ali; Woznicki, Elise; Montgomery, Dan; Isselbacher, Eric M.; Di Bartolomeo, Roberto; Fattori, Rossella; Nienaber, Christoph A.; Eagle, Kim A.; Trimarchi, Santi

    2016-01-01

    Type A acute aortic dissection (TAAD) is a disease that has a catastrophic impact on a patient’s life and emergent surgery represents a key goal of early treatment. Despite continuous improvements in imaging techniques, medical therapy and surgical management, early mortality in patients undergoing TAAD repair still remains high, ranging from 17% to 26%. In this setting, the International Registry of Acute Aortic Dissection (IRAD), the largest worldwide registry for acute aortic dissection, was established to assess clinical characteristics, management and outcomes of TAAD patients. The present review aimed to evaluate and comment on outcomes of TAAD surgery as reported from IRAD series. PMID:27563547

  9. Electrophysiological fingerprints of OFF bipolar cells in rat retina.

    PubMed

    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. 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

  11. Clinical electrophysiology in myasthenia gravis.

    PubMed Central

    Stalberg, E

    1980-01-01

    Effective diagnostic methods are of great importance in order to recognise myasthenic patients among those with muscle fatigability. Intracellular recordings are useful for research work within the field and for detailed description of the motor end-plate's physiology in the individual case. The method is not used for the routine diagnosis of myasthenia gravis. The decrement of the electrical muscle response with nerve stimulation is the most commonly used method. The diagnostic yield is higher in proximal muscles, in warmed muscles, after exercise, and after ischaemia. A significant number of patients may be undiagnosed with this technique. The mechanical response with nerve stimulation shows the same type of decrement but also an abnormal response to long stimulation. The diagnostic value of this is under dispute. Single fibre ENG needs more patient cooperation than do these tests. The diagnostic yield is significantly higher. Some patients considered to have myasthenia gravis do not show any abnormalities with this technique, particularly those with the pure ocular form. Conventional EMG is not useful for the diagnosis of myasthenia, but may be indicated in these patients when concurrent nerve or muscle disease is in question. Tests for eye movement fatique have not proved useful. Stapedius reflex fatigability is demonstrated in about the same proportion of patients as have positive SFEMG findings. The technique is not uncomfortable for the patient and requires minimal cooperation. The general usefulness must be assessed by further routine use. Even with the advent of immunological tests, neurophysiological investigations are indispensable in helping establish the diagnosis of myasthenia gravis. Discrepancies between the results comparing electrophysiological and immunological tests may indicate that myasthenia gravis is a heterogenous entity within which subgroups may be identified. PMID:6249895

  12. Early experiences with a porcine hepatocyte-based bioartificial liver in acute hepatic failure patients.

    PubMed

    Morsiani, E; Pazzi, P; Puviani, A C; Brogli, M; Valieri, L; Gorini, P; Scoletta, P; Marangoni, E; Ragazzi, R; Azzena, G; Frazzoli, E; Di Luca, D; Cassai, E; Lombardi, G; Cavallari, A; Faenza, S; Pasetto, A; Girardis, M; Jovine, E; Pinna, A D

    2002-03-01

    Orthotopic liver transplantation (OLT) is the only effective therapeutic modality in severe acute hepatic failure (AHF). The scarcity of organs for transplantation leads to an urgent necessity for temporary liver support treatments in AHF patients. A hepatocyte-based bioartificial liver (BAL) is under investigation with the main purpose to serve as bridging treatment until a liver becomes available for OLT, or to promote spontaneous liver regeneration. We developed a novel radial-flow bioreactor (RFB) for three-dimensional, high-density hepatocyte culture and an integrated pumping apparatus in which, after plasmapheresis, the patient's plasma is recirculated through the hepatocyte-filled RFB. Two hundred thirty grams of freshly isolated porcine hepatocytes were loaded into the RFB for clinical liver support treatment. The BAL system was used 8 times in supporting 7 AHF patients in grade III-IV coma, all waiting for an urgent OLT Three patients with no history of previous liver diseases were affected by fulminant hepatic failure (FHF) due to hepatitis B virus, 3 by primary non-function (PNF) of the transplanted liver, and one by AHF due to previous abdominal trauma and liver surgery. Six out of 7 patients underwent OLT following BAL treatment(s), which lasted 6-24 hours. All patients tolerated the procedures well, as shown by an improvement in the level of encephalopathy, a decrease in serum ammonia, transaminases and an amelioration of the prothrombin time, with full neurological recovery after OLT Our initial clinical experience confirms the safety of this BAL configuration and suggests its clinical efficacy as a temporary liver support system in AHF patients. PMID:11999191

  13. Timely embolectomy in acute massive pulmonary embolism prevents catastrophe: An experience from two cases

    PubMed Central

    Ramesh, Dwarakaprasad; Setty, Huliyurdurga Srinivasasetty Natraj; Kumarswamy; Kumar, Sunil; Jayanth; Manjunath, Cholenahalli Nanjappa

    2016-01-01

    Acute massive pulmonary embolism is a life-threatening emergency that must be promptly diagnosed and managed. Over the last several years, the use of computed tomography scanning has improved the clinician's ability to diagnose acute pulmonary embolism. We report two cases of acute massive pulmonary embolism who presented with sudden onset of dyspnea and underwent successful open pulmonary embolectomy. The first case presented with acute onset of dyspnea of 2 days duration, in view of hemodynamic deterioration and two-dimensional echocardiography, it revealed clot in right ventricular (RV) apex and right pulmonary artery; the patient underwent cardiopulmonary bypass and open pulmonary embolectomy with RV clot extraction. The second case presented with a sudden onset of dyspnea on the 15th postoperative day for traumatic rupture of urinary bladder, in view of recent surgery, the patient was subjected to surgical embolectomy. Following surgical intervention, both the patients made a prompt recovery. PMID:27433070

  14. Acute Ataxia in Childhood: 11-Year Experience at a Major Pediatric Neurology Referral Center.

    PubMed

    Thakkar, Kavita; Maricich, Stephen M; Alper, Gulay

    2016-08-01

    We categorized the causes of acute ataxia in the pediatric population-referred to the Division of Neurology-at a large, urban pediatric medical center. Of the 120 cases identified over the past 11 years, post-infectious cerebellar ataxia was the most commonly diagnosed (59%), followed by drug intoxication, opsoclonus-myoclonus ataxia syndrome, episodic ataxia, acute cerebellitis, cerebellar stroke, ADEM, meningitis, cerebral vein thrombosis, Leigh's disease, Miller-Fisher syndrome, and concussion. Among the patients with post-infectious cerebellar ataxia, 85% were 1-6 years old and all had a history of antecedent viral illness. CSF pleocytosis was present in 40% of patients; all had normal brain MRIs. The majority (91%) recovered within 30 days. We conclude that post-infectious cerebellar ataxia remains the most common cause of acute ataxia in childhood and that it carries a good prognosis. We also differentiate acute post-infectious cerebellar ataxia from other causes with similar presentations. PMID:27071467

  15. 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.

  16. Haploidentical hematopoietic stem cell transplantation without total body irradiation for pediatric acute leukemia: a single-center experience

    PubMed Central

    Mu, Yanshun; Qin, Maoquan; Wang, Bin; Li, Sidan; Zhu, Guanghua; Zhou, Xuan; Yang, Jun; Wang, Kai; Lin, Wei; Zheng, Huyong

    2016-01-01

    Hematopoietic stem cell transplantation (HSCT) is a promising method for therapy of pediatric patients with acute leukemia. However, less availability of matched donors limited its wide application. Recently, haploidentical HSCT has become a great resource. Here, we have retrospectively reported our experience of 20 pediatric patients with acute leukemia who underwent haploidentical HSCT without total body irradiation (TBI) myeloablative regimen in our center from November 2007 to June 2014. All the patients attained successful HSCT engraftment in terms of myeloid and platelet recovery. Thirteen patients developed grade I–IV acute graft-versus-host disease (a-GVHD). The incidence of grade I–II a-GVHD, grade III–IV a-GVHD, and chronic GVHD (c-GVHD) was 45%, 20%, and 25%, respectively. The mean myeloid and platelet recovery time was 13.20±2.41 and 19.10±8.37 days. The median follow-up time was 43.95±29.26 months. During the follow-up, three patients died. The overall survival (OS) rate was 85%. The present study indicated that haploidentical HSCT without TBI myeloablative regimen significantly improved the OS rate of pediatric patients with acute leukemia. PMID:27217774

  17. Serial electrophysiological findings in Guillain-Barré syndrome not fulfilling AIDP or AMAN criteria.

    PubMed

    Hosokawa, Takafumi; Nakajima, Hideto; Unoda, Kiichi; Yamane, Kazushi; Doi, Yoshimitsu; Ishida, Shimon; Kimura, Fumiharu; Hanafusa, Toshiaki

    2016-09-01

    Guillain-Barré syndrome (GBS) is categorized into two major subtypes: acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). However, a proportion of patients are electrophysiologically unclassified because of electrophysiological findings that do not fulfil AIDP or AMAN criteria, and underlying pathophysiological mechanisms and lesion distributions of unclassified patients are not well defined. The aims of this study are to elucidate disease pathophysiology and lesion distribution in unclassified patients. We retrospectively studied 48 consecutive GBS patients. Patients were classified on the basis of initial electrophysiological findings according to Ho's criteria. Clinical and serial electrophysiological examinations of unclassified patients were conducted. Twelve (25 %) GBS patients were unclassified. All unclassified patients were able to walk independently at 21 days after onset. No unclassified patients, except one patient with diabetes mellitus, had sensory nerve involvement. Eight patients underwent a follow-up study within 15 days of the initial study. Distal motor latencies (DMLs) of the left median motor nerve were found to be significantly and uniformly decreased compared with initial studies (p = 0.008). DMLs (p < 0.0001) and distal compound action potential (CMAP) durations (p = 0.002) of all nerves were significantly decreased, and distal CMAP amplitudes (p = 0.026) significantly increased compared with initial studies. In unclassified GBS patients, DML values during initial electrophysiological studies would be prolonged compared with expected values in the same patient unaffected by GBS and later improve rapidly with increased distal CMAP amplitudes without the development of excessive temporal dispersions. Lesions are also present in distal nerve segments caused by reversible conduction failure. PMID:27278064

  18. Real-time Electrophysiology: Using Closed-loop Protocols to Probe Neuronal Dynamics and Beyond.

    PubMed

    Linaro, Daniele; Couto, João; Giugliano, Michele

    2015-01-01

    Experimental neuroscience is witnessing an increased interest in the development and application of novel and often complex, closed-loop protocols, where the stimulus applied depends in real-time on the response of the system. Recent applications range from the implementation of virtual reality systems for studying motor responses both in mice and in zebrafish, to control of seizures following cortical stroke using optogenetics. A key advantage of closed-loop techniques resides in the capability of probing higher dimensional properties that are not directly accessible or that depend on multiple variables, such as neuronal excitability and reliability, while at the same time maximizing the experimental throughput. In this contribution and in the context of cellular electrophysiology, we describe how to apply a variety of closed-loop protocols to the study of the response properties of pyramidal cortical neurons, recorded intracellularly with the patch clamp technique in acute brain slices from the somatosensory cortex of juvenile rats. As no commercially available or open source software provides all the features required for efficiently performing the experiments described here, a new software toolbox called LCG was developed, whose modular structure maximizes reuse of computer code and facilitates the implementation of novel experimental paradigms. Stimulation waveforms are specified using a compact meta-description and full experimental protocols are described in text-based configuration files. Additionally, LCG has a command-line interface that is suited for repetition of trials and automation of experimental protocols. PMID:26132434

  19. 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

  20. Acute intraperitoneal rupture of hydatid cysts: a surgical experience with 14 cases

    PubMed Central

    2013-01-01

    differential diagnosis of acute abdomen in endemic areas. The operative procedures, either radical or conservative, should be based on the patient’s condition, the regional characteristics, and the surgeon’s experience. The morbidity and mortality rates of surgical interventions for ruptured hydatid cysts are higher than the rates for elective uncomplicated cases. PMID:23885766

  1. Stepping Back and Listening: Staff Experiences of Using a Coaching Approach in an Acute Rehabilitation Ward for Older Adults.

    PubMed

    Gray, Debra; Ross, Kirsty; Prat-Sala, Merce; Kibble, Sharon; Harden, Beverley

    2016-08-01

    Previous research has highlighted that acute care provision can lead to a loss of confidence, control, and independent functioning in older adult patients. In addition, it is recognized that interactions between patients and health care staff are central to the prevention of functional decline in patients. In this study, we aimed to affect the staff-patient relationship by implementing a coaching intervention in an older adult acute care setting. Here, we report on staff experiences of this coaching approach. Data were collected from 16 members of staff via semi-structured interviews, which were analyzed using thematic analysis. Four themes were identified: Putting a Label on It, Stepping Back and Listening, Identifying the Opportunities, and Working as Team. Our findings show that a coaching approach can be successful in getting staff to reconsider their interactions with patients and to focus on strategies that foster the independence and autonomy of older adult patients. PMID:26481943

  2. [Nurse's experience of using music therapy to relieve acute pain in a post-orthopedic surgery patient].

    PubMed

    Hsiao, Tsai-Yun; Hsieh, Hsiu-Fang

    2009-08-01

    This article describes the experience of a nurse who used music therapy as the intervention to reduce a patient's pain during wound care after orthopedic surgery. The intervention was applied between April 8th and April 29th 2008. The nurse applied Roy's adaptation model as the assessment tool. The major and primary health problem identified was acute pain accelerated by wound care. The pain of this client not only triggered negative feelings, but also affected negatively on his daily life and feelings of self-belongingness. Through an individual-tailored music therapy, the client's pain during wound care was greatly reduced and even completely disappeared. The ultimate outcome of decrease in pain included reductions in negative feelings and increased positive spiritual strength. It is recommended that nurses who are responsible for wound care use this simple and economical music intervention to reduce acute postoperative pain. PMID:19634107

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

    PubMed Central

    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. PMID:24550801

  4. 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

  5. Changing Trends in Treatment of Acute Mania: Experience of a Tertiary Centre Over a Decade.

    PubMed

    Arıkan, Mehmet Kemal; Poyraz, Cana Aksoy; Baş, Alper; Sağlam, N Gamze Usta; Batun, Gizem Cetiner; Gültekin, Gözde; Poyraz, Burç Çağrı

    2016-06-01

    We investigated trends over a decade in the prescription of lithium, antiepileptics, and antipsychotic agents at discharge for patients hospitalised for acute mania. We conducted a retrospective review of medical records for 165 inpatients with acute mania who had been hospitalised in Cerrahpaşa Faculty of Medicine, Department of Psychiatry during 2001-2002 and 2011-2012. Among 165 patients, prescription of olanzapine at discharge increased from 3 to 46 % (p < 0.001), while prescription of haloperidol decreased from 55 to 21 % (p < 0.001). Use of other atypical antipsychotics did not change significantly (risperidone decreased from 14 to 11 %, p = 0.5; quetiapine increased from 10 to 16 %, p = 0.2). Use of valproate, carbamazepine, and lithium did not change significantly. Use of electroconvulsive therapy in acute mania decreased by half from 27 to 13 % (p = 0.02). Typical antipsychotics alone or in combination with antiepileptics were the most common treatment regimen at discharge at 2001-2002; while 10 years later, they had been largely replaced by lithium or antiepileptics combined with second generation antipsychotics. Antipsychotic agents remained to be an important component of acute treatment of mania in our practice. PMID:26220636

  6. Technetium pyrophosphate scanning in the detection of acute myocardial infarction: clinical experience.

    PubMed Central

    Ko, P.; Kostuk, W. J.; Deatrich, D.

    1977-01-01

    Technetium-99m-stannous pyrophosphate (99mTc-PYP) accumulates in acutely infarcted myocardium and can be detected by scintiscanning. The clinical value of 99mTc-PYP scintiscanning was studied in 83 patients 6 hours to 21 days after the onset of acute chest pain. In 12 patients with normal electrocardiograms and serum enzyme values no uptake of 99mTc-PYP was detected on the scintigrams. Of 44 patients with electrocardiographic or enzyme evidence, or both, of acute myocardial infarction the scintigrams were positive in 31, "questionable" in 2 and negative in 11; no positive scan was obtained within 12 hours of the onset of pain, and the scans generally remained positive for up to 5 days. In 24 patients with evidence of prolonged myocardial ischemia the scans were positive in 2, questionable in 4 and negative in 18. The scans were negative in each of three patients with acute or constrictive pericarditis. Localization by electrocardiography and scintiscanning correlated nearly perfectly for transmural infarcts but subendocardial infarcts could not always be localized precisely by scintiscanning. The infarct area (total area of 99mTc-PYP uptake) correlated well with the peak serum value of creatine phosphokinase. Images FIG. 1 FIG. 2 FIG. 3 FIG. 5 PMID:189887

  7. 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.

  8. In vitro closed loop optical network electrophysiology: An introduction

    NASA Astrophysics Data System (ADS)

    Hady, A. El; Stühmer, W.

    2013-01-01

    We present a novel experimental paradigm "In vitro closed loop optical network electrophysiology (ivCLONE)". This seminar note gives an overviewof the basics of optical neurostimulation, network electrophysiology and closed loop electrophysiology. Moreover, the notes discuss how combination of aforementioned techniqueswould help us to address network-level phenomenon and how single neuron properties are related to collective network dynamics.

  9. Peripheral Neuropathy – Clinical and Electrophysiological Considerations

    PubMed Central

    Chung, Tae; Prasad, Kalpana; Lloyd, Thomas E.

    2013-01-01

    This article is a primer on the pathophysiology and clinical evaluation of peripheral neuropathy for the radiologist. Magnetic resonance neurography (MRN) has utility in the diagnosis of many focal peripheral nerve lesions. When combined with history, examination, electrophysiology, and laboratory data, future advancements in high-field MRN may play an increasingly important role in the evaluation of patients with peripheral neuropathy. PMID:24210312

  10. 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. PMID:26403429

  11. Early UK experience in the use of clofarabine in the treatment of relapsed and refractory paediatric acute lymphoblastic leukaemia.

    PubMed

    O'Connor, David; Sibson, Keith; Caswell, Mark; Connor, Philip; Cummins, Michelle; Mitchell, Chris; Motwani, Jayashree; Taj, Mary; Vora, Ajay; Wynn, Robert; Kearns, Pamela R

    2011-08-01

    Clofarabine is a second-generation purine nucleoside analogue, which has shown promising activity in relapsed and refractory paediatric acute lymphoblastic leukaemia (ALL). This report summarizes the early United Kingdom experience of clofarabine for the treatment of paediatric ALL in 23 patients, outside of the context of a clinical trial. Our results demonstrated that clofarabine-based chemotherapy regimes were effective and well-tolerated in this heavily pre-treated group, with an overall response rate of 67% when used in combination regimes. Responses were seen in both B and T cell disease and in patients with adverse cytogenetics. PMID:21689087

  12. 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

  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. Acute renal failure in pregnancy: Tertiary centre experience from north Indian population

    PubMed Central

    Patel, Munna Lal; Sachan, Rekha; Radheshyam; Sachan, Pushpalata

    2013-01-01

    Background: Obstetrical acute renal failure ARF is now a rare entity in the developed countries but still a common occurrence in developing countries. Delay in the diagnosis and late referral is associated with increased mortality. This study aimed to evaluate the contributing factors responsible for pregnancy-related acute kidney failure, its relation with mortality and morbidity and outcome measures in these patients. Materials and Methods: Total 520 patients of ARF of various aetiology were admitted, out of these 60 (11.5%) patients were pregnancy-related acute renal failure. Results: ARF Acute renal failure occurred in 32 (53.3%) cases in early part of their pregnancy, whereas in 28 (46.7%) cases in later of the pregnancy. Thirty-two (53.3%) patients had not received any antenatal visit, and had home delivery, 20 (33.4%) patients had delivered in hospitals but without antenatal care and eight (13.3%) patients received antenatal care and delivered in the hospitals. Anuria was observed in 23 (38.3%) cases, remaining 37 (61.7%) cases presented with oliguria. Septicemia was present in 25 (41.7%), hypertensive disorder of pregnancy in 20 (33.3%), haemorrhage in eight (13.3%), abortion in 5 (8.3%), haemolysis elevated liver enzymes low platelets counts (HELLP) syndrome in one (1.67%) and disseminated intravascular coagulation in one (1.67%). (61.7%) patients were not dialyzed, 33 (55%) recovered normal renal function with conservative treatment. Complete recovery was observed in 45 (75%) patients, five (8.4%) patients developed irreversible renal failure. Maternal mortality was nine (15%) and foetal loss was 25 (41.7%). Conclusion: Pregnancy-related ARF is usually a consequence of obstetric complications; it carries very high morbidity and mortality. PMID:23900700

  15. 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. PMID:26713060

  16. 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

  17. 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

  18. Application of arm support training in sub-acute stroke rehabilitation: first results on effectiveness and user experiences.

    PubMed

    Prange, G B Gerdienke; Kottink, Air Anke; Buurke, J H Jaap; Rietman, J S Hans

    2013-06-01

    A multi-center randomized clinical trial was performed in 7 Dutch rehabilitation centers, in the context of an implementation project (ROBAR), to compare the effect of an arm support (AS) training device to equally intensive conventional reach training (CON) on recovery of arm-hand function in sub-acute stroke. The Fugl-Meyer assessment (FM) and user experiences of therapists and patients were examined in both groups. An improvement of 10 and 8 points on the FM was found for respectively the CON and AS group. Both therapists and patients reported positive experiences on several aspects of user acceptance. These findings indicate that a low-tech system for arm support results in similar gains in arm function as conventional reach training in equal intensity, and is suitable for application in clinical practice. PMID:24187287

  19. Low risk of transmission of severe acute respiratory syndrome on airplanes: the Singapore experience.

    PubMed

    Wilder-Smith, Annelies; Paton, Nicholas I; Goh, Kee Tai

    2003-11-01

    The risk of transmission of severe acute respiratory syndrome (SARS) on airplanes is of major concern to the public and airline industry. We examined data from flights to Singapore with SARS patients on board in order to assess this risk. In-flight transmission occurred only in one of the three flights with symptomatic SARS patients on board. The incidence was estimated to be 1 out of 156 passengers. The risk of in-flight transmission of SARS appears to be far lower than that reported for influenza, but may be increased with superspreaders on board. PMID:14629772

  20. Electrophysiology of Single and Aggregate Cx43 Hemichannels

    PubMed Central

    Brokamp, Cole; Todd, Jacob; Montemagno, Carlo; Wendell, David

    2012-01-01

    Connexin43 (Cx43) is the most ubiquitous gap junction protein in the human body and is essential for cell-to-cell communication in a variety of organs and organ systems. As a result, Cx43 is responsible for mediating both electrical and chemical signals, passing dissolved solutes and small signaling molecules between cells in a coordinated fashion. Here, we explore the electrophysiological properties of hemichannels formed from Cx43 and Cx43 fused to eGFP (Cx43eGFP) and their interactions in a planar lipid membrane (BLM). Unlike in vivo patch clamp experiments, Cx43 was purified and isolated from other membrane constituents allowing elucidation of individual protein responses to various electrical and chemical stimuli. Using this system, we examined hemichannel electrophysiology and the roles of several well-known gap junction blockers, namely: lanthanum, heptanol, carbenoxalone and lindane. We also observed a critical number of hemichannels required for an accelerated conductance increase, an emergent electrical signature indicative of plaque formation. PMID:23112846

  1. Electrophysiological recording in the brain of intact adult zebrafish.

    PubMed

    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

  2. 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

  3. Life in acute mental health settings: experiences and perceptions of service users and nurses.

    PubMed

    Rose, D; Evans, J; Laker, C; Wykes, T

    2015-02-01

    Background. Acute psychiatric provision in the UK today as well as globally has many critics including service users and nurses. Method. Four focus groups, each meeting twice, were held separately for service users and nurses. The analysis was not purely inductive but driven by concerns with the social position of marginalised groups - both patients and staff. Results. The main themes were nurse/patient interaction and coercion. Service users and nurses conceptualised these differently. Service users found nurses inaccessible and uncaring, whereas nurses also felt powerless because their working life was dominated by administration. Nurses saw coercive situations as a reasonable response to factors 'internal' to the patient whereas for service users they were driven to extreme behaviour by the environment of the ward and coercive interventions were unnecessary and heavy handed. Conclusion. This study sheds new light on living and working in acute mental health settings today by comparing the perceptions of service users and nurses and deploying service user and nurse researchers. The intention is to promote better practice by providing a window on the perceptions of both groups. PMID:24330951

  4. On the electrophysiology of aesthetic processing.

    PubMed

    Jacobsen, Thomas

    2013-01-01

    One important method that can be applied for gaining an understanding of the underpinning of aesthetics in the brain is that of electrophysiology. Cognitive electrophysiology, in particular, allows the identification of components in a mental processing architecture. The present chapter reviews findings in the neurocognitive psychology of aesthetics, or neuroaesthetics, that have been obtained with the method of event-related brain potentials, as derived from the human electroencephalogram. The cognitive-perceptual bases as well as affective substages of aesthetic processing have been investigated and those are described here. The event-related potential method allows for the identification of mental processing modes in cognitive and aesthetic processing. It also provides an assessment of the mental chronometry of cognitive and affective stages in aesthetic appreciation. As the work described here shows, distinct processes in the brain are engaged in aesthetic judgments. PMID:24041323

  5. Python for Large-Scale Electrophysiology

    PubMed Central

    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. PMID:19198646

  6. Patch-Clamp Fluorometry: Electrophysiology meets Fluorescence

    PubMed Central

    Kusch, Jana; Zifarelli, Giovanni

    2014-01-01

    Ion channels and transporters are membrane proteins whose functions are driven by conformational changes. Classical biophysical techniques provide insight into either the structure or the function of these proteins, but a full understanding of their behavior requires a correlation of both these aspects in time. Patch-clamp and voltage-clamp fluorometry combine spectroscopic and electrophysiological techniques to simultaneously detect conformational changes and ionic currents across the membrane. Since its introduction, patch-clamp fluorometry has been responsible for invaluable advances in our knowledge of ion channel biophysics. Over the years, the technique has been applied to many different ion channel families to address several biophysical questions with a variety of spectroscopic approaches and electrophysiological configurations. This review illustrates the strength and the flexibility of patch-clamp fluorometry, demonstrating its potential as a tool for future research. PMID:24655500

  7. [Fundamental ophthalmology: the role of electrophysiological studies].

    PubMed

    Zueva, M V

    2014-01-01

    Studying of functional aspects of eye disease pathogenesis by electrophysiological methods is widely demanded in fundamental ophthalmology. Introduction of modern methods of functional assessment into experimental and clinical projects significantly broadens knowledge of normal and pathological functioning of the visual system and is the basis for further development of new strategies of pathogenetic treatment, diagnostics and expert evaluation. Some problems of ophthalmology, including those that concern age-related macular degeneration, glaucoma, diabetic retinopathy, and other diseases, are considered in the context of how much electrophysiology contributes to their solution. The role of functional examinations of the retina in studying pathophysiology of neurodegenerative brain diseases, such as Alzheimer's and Parkinson's, is also discussed. PMID:25715550

  8. 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.}

  9. 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

  10. ICEPO: the ion channel electrophysiology ontology

    PubMed Central

    Hinard, V.; Britan, A.; Rougier, J.S.; Bairoch, A.; Abriel, H.; Gaudet, P.

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site: ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  11. 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.

  12. ICEPO: the ion channel electrophysiology ontology.

    PubMed

    Hinard, V; Britan, A; Rougier, J S; Bairoch, A; Abriel, H; Gaudet, P

    2016-01-01

    Ion channels are transmembrane proteins that selectively allow ions to flow across the plasma membrane and play key roles in diverse biological processes. A multitude of diseases, called channelopathies, such as epilepsies, muscle paralysis, pain syndromes, cardiac arrhythmias or hypoglycemia are due to ion channel mutations. A wide corpus of literature is available on ion channels, covering both their functions and their roles in disease. The research community needs to access this data in a user-friendly, yet systematic manner. However, extraction and integration of this increasing amount of data have been proven to be difficult because of the lack of a standardized vocabulary that describes the properties of ion channels at the molecular level. To address this, we have developed Ion Channel ElectroPhysiology Ontology (ICEPO), an ontology that allows one to annotate the electrophysiological parameters of the voltage-gated class of ion channels. This ontology is based on a three-state model of ion channel gating describing the three conformations/states that an ion channel can adopt: closed, open and inactivated. This ontology supports the capture of voltage-gated ion channel electrophysiological data from the literature in a structured manner and thus enables other applications such as querying and reasoning tools. Here, we present ICEPO (ICEPO ftp site:ftp://ftp.nextprot.org/pub/current_release/controlled_vocabularies/), as well as examples of its use. PMID:27055825

  13. Utility of urgent colonoscopy in acute lower gastro-intestinal bleeding: a single-center experience

    PubMed Central

    Albeldawi, Mazen; Ha, Duc; Mehta, Paresh; Lopez, Rocio; Jang, Sunguk; Sanaka, Madhusudhan R.; Vargo, John J.

    2014-01-01

    Background. The role of urgent colonoscopy in lower gastro-intestinal bleeding (LGIB) remains controversial. Over the last two decades, a number of studies have indicated that urgent colonoscopy may facilitate the identification and treatment of bleeding lesions; however, studies comparing this approach to elective colonoscopy for LGIB are limited. Aims. To determine the utility and assess the outcome of urgent colonoscopy as the initial test for patients admitted to the intensive care unit (ICU) with acute LGIB. Methods. Consecutive patients who underwent colonoscopy at our institution for the initial evaluation of acute LGIB between January 2011 and January 2012 were analysed retrospectively. Patients were grouped into urgent vs. elective colonoscopy, depending on the timing of colonoscopy after admission to the ICU. Urgent colonoscopy was defined as being performed within 24 hours of admission and those performed later than 24 hours were considered elective. Outcomes included length of hospital stay, early re-bleeding rates, and the need for additional diagnostic or therapeutic interventions. Multivariable logistic regression analysis was performed to identify factors associated with increased transfusion requirements. Results. Fifty-seven patients underwent colonoscopy for the evaluation of suspected LGIB, 24 of which were urgent. There was no significant difference in patient demographics, co-morbidities, or medications between the two groups. Patients who underwent urgent colonoscopy were more likely to present with hemodynamic instability (P = 0.019) and require blood transfusions (P = 0.003). No significant differences in length of hospital stay, re-bleeding rates, or the need for additional diagnostic or therapeutic interventions were found. Patients requiring blood transfusions (n = 27) were more likely to be female (P = 0.016) and diabetics (P = 0.015). Fourteen patients re-bled at a median of 2 days after index colonoscopy. Those with hemodynamic

  14. 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

  15. Household bleaches based on sodium hypochlorite: review of acute toxicology and poison control center experience.

    PubMed

    Racioppi, F; Daskaleros, P A; Besbelli, N; Borges, A; Deraemaeker, C; Magalini, S I; Martinez Arrieta, R; Pulce, C; Ruggerone, M L; Vlachos, P

    1994-09-01

    Bleaches based on solutions of sodium hypochlorite (NaOCl) are widely used in the household to disinfect and clean hard surfaces and to bleach the laundry. A review of both published and unpublished toxicological data is presented. In addition, the results of a survey of human accidents with hypochlorite bleaches by the Poison Control Centers of France, Italy, Belgium, Greece, Turkey, Spain and Portugal for the period 1989-1992 are presented. The data show that acute accidental exposure to household bleach in use or in foreseeable misuse situations results, in the great majority of the cases, in minor, transient adverse effects on health, with no permanent sequelae. Ingestion is the most frequent route of exposure, followed by inhalation of gases evolved by mixing sodium hypochlorite bleach with acid or alkaline products. All evidence presented confirms the normal safety profile of hypochlorite-based bleaches to be similar to that of other 'generally recognized as safe' household products. PMID:7927083

  16. Acute Myeloid Leukemia in Children: Experience from Tertiary Cancer Centre in India.

    PubMed

    Radhakrishnan, Venkatraman; Thampy, Cherian; Ganesan, Prasanth; Rajendranath, Rejiv; Ganesan, Trivadi S; Rajalekshmy, K R; Sagar, Tenali Gnana

    2016-09-01

    There is paucity of data in pediatric Acute Myeloid Leukemia (AML) from developing countries. We analyzed the outcomes of 65 consecutive patients with pediatric AML treated at our centre from January-2008 to May-2013. The median event free survival (EFS) and overall survival (OS) were 12.6 and 14.6 months respectively. Patients with good-risk cytogenetics had a better EFS (p = 0.004) and OS (p = 0.01). Overall, these results are not comparable to that observed in other centres globally and leaves scope for further improvement. This includes implementing allogeneic bone marrow transplantation as a treatment for all children with high-risk AML. PMID:27429516

  17. Precipitant profile of acute heart failure: experience of a tertiary level cardiac centre in Sri Lanka

    PubMed Central

    Matthias, Anne Thushara; Ekanayaka, Ruvan

    2013-01-01

    Introduction and objectives Heart failure (HF) is a common cause of hospitalisation in most countries. Data on acute precipitants of HF and hospitalisation is not available in Sri Lanka. Background and methods A prospective study of 100 sequential admissions with HF to the cardiology unit (National Hospital of Sri Lanka) to describe the precipitants and clinical outcome of HF. Results Fifty-eight male and 42 female admissions were studied. Mean age was 60.66 years. Mean hospital stay was 5.5(SD 4.6) days. Sixty had de novo HF and 40 had pre-existing HF. The most common identifiable precipitants were acute ischaemia 37 (37%), anaemia 41 (41%), respiratory tract infection 10 (10%), arrhythmia 11 (11%), worsening renal function 11 (11%) and alcohol 5 (5.7%). Non-adherence to medication 4 (4.6%), smoking 3 (3.9%), exposure to environmental stress 3 (3.4%) and uncontrolled hypertension 1 (1%) were also observed as precipitants. The most common arrhythmia was atrial fibrillation. Out of 34 patients in whom angiotensin-converting enzyme inhibitors or angiotensin-converting enzyme receptor blockers were indicated, 11% were not on the drug. Among 29 patients in whom spironolactone was indicated, seven patients were not on the drug. Conclusions Most precipitating factors of HF are preventable. Early identification and prevention of anaemia, preventing respiratory tract infection by vaccination, aggressive revascularisation for patients with ischaemia, monitoring of renal functions, and patient education regarding drug and diet compliance, would reduce the number of admissions. PMID:27326091

  18. Febrile neutropenia in children with acute lymphoblastic leukemia: single center experience

    PubMed Central

    Özdemir, Nihal; Tüysüz, Gülen; Çelik, Nigar; Yantri, Leman; Erginöz, Ethem; Apak, Hilmi; Özkan, Alp; Yıldız, İnci; Celkan, Tiraje

    2016-01-01

    Aim: An important life-threatening complication of intensive chemotherapy administered in children with leukemia is febrile neutropenia. The objective of this study was to evaluate the clinical features and consequences of febrile neutropenia attacks in children who were treated for acute lymphoblastic leukemia. Material and Methods: Nighty-six children who received chemotherapy for acute lymphoblastic leukemia in our center between January 1995 and December 2010 were included in the study. The data related to demographic characteristics, treatment features, relapse and febrile neutropenia incidences, risk factors, culture results and prognosis were retrospectively evaluated from the patients’ files. Results: A total of two hundred-ninety nine febrile neutropenia attacks observed in the patients during initial treatment and relapse treatment were evaluated. When the incidence of febrile neutropenia was evaluated by years, it was observed that the patients treated after year 2000 had statistically significantly more febrile neutopenia attacks compared to the patients treated before year 2000. When the incidences of febrile neutropenia during initial treatment and during relapse treatment were compared, it was observed that more febrile neutropenia attacks occured during relapse treatment. Fifty-nine percent of all febrile neutropenia attacks were fever of unknown origin. Eighty microorganisms grew in cultures during febrile neutropenia throughout treatment in 75 patients; 86% were bacterial infections (50% gram positive and 50% gram negative), 8% were viral infections and 6% were fungal infections. Coagulase negative staphylococcus (n=17) was the most frequent gram positive pathogen; E. Coli (n=17) was the most commonly grown gram negative pathogen. Conclusions: In this study, it was found that an increase in the incidence of febrile neutropenia occured in years. Increments in treatment intensities increase the incidence of febrile neutropenia while improving

  19. Peritoneal Dialysis in Childhood Acute Kidney Injury: Experience in Southwest Nigeria

    PubMed Central

    Ademola, Adebowale Dele; Asinobi, Adanze Onyenonachi; Ogunkunle, Oluwatoyin Olufunmilayo; Yusuf, Bamidele Nurudeen; Ojo, Olalekan Ezekiel

    2012-01-01

    ♦ Background: The choices for renal replacement therapy (RRT) in childhood acute kidney injury (AKI) are limited in low-resource settings. Peritoneal dialysis (PD) appears to be the most practical modality for RRT in young children with AKI in such settings. Data from sub-Saharan Africa on the use of PD in childhood AKI are few. ♦ Methods: We performed a retrospective study of children who underwent PD for AKI at a tertiary-care hospital in southwest Nigeria from February 2004 to March 2011 (85 months). ♦ Results: The study included 27 children (55.6% female). Mean age was 3.1 ± 2.6 years, with the youngest being 7 days, and the oldest, 9 years. The causes of AKI were intravascular hemolysis (n = 11), septicemia (n = 8), acute glomerulonephritis (n = 3), gastroenteritis (n = 3), and hemolytic uremic syndrome (n = 2). Peritoneal dialysis was performed manually using percutaneous or adapted catheters. Duration of PD ranged from 6 hours to 12 days (mean: 5.0 ± 3.3 days). The main complications were peritonitis (n = 10), pericatheter leakage (n = 9), and catheter outflow obstruction (n = 5). Of the 27 patients, 19 (70%) survived till discharge. ♦ Conclusions: In low-resource settings, PD can be successfully performed for the management of childhood AKI. In our hospital, the use of adapted catheters may have contributed to the high complication rates. Peritoneal dialysis should be promoted for the management of childhood AKI in low-resource settings, and access to percutaneous or Tenckhoff catheters, dialysis fluid, and automated PD should be increased. PMID:22550119

  20. Event-level associations between affect, alcohol intoxication, and acute dependence symptoms: Effects of urgency, self-control, and drinking experience

    PubMed Central

    Simons, Jeffrey S.; Dvorak, Robert D.; Batien, Bryan D.; Wray, Tyler B.

    2012-01-01

    This study used experience sampling to examine within-person associations between positive affect, anxiety, sadness, and hostility and two outcomes: alcohol intoxication and acute dependence symptoms. We examined the role of urgency, premeditation, and perseverance in predicting the alcohol outcomes and tested whether the affective associations varied as a function of urgency. Participants completed baseline assessments and 21 days of experience sampling on PDAs. Hypotheses were partially confirmed. Positive affect was positively, and sadness inversely, associated with intoxication. Hostility was associated with intoxication for men but not women. Negative urgency moderated the association between anxiety and intoxication, making it stronger. However, positive urgency did not moderate the effect of positive affect. Heavier drinkers exhibited the greatest number of symptoms, yet the association between intoxication and acute signs of alcohol disorder were attenuated among these individuals. Results support the use of experience sampling to study acute signs and symptoms of high risk drinking and dependence. PMID:20685044

  1. Is a good death possible in Australian critical and acute settings?: physician experiences with end-of-life care

    PubMed Central

    2014-01-01

    Background In Australia approximately 70% of all deaths are institutionalised but over 15% of deaths occur in intensive care settings where the ability to provide a “good death” is particularly inhibited. Yet, there is a growing trend for death and dying to be managed in the ICU and physicians are increasingly challenged to meet the new expectations of their specialty. This study examined the unexplored interface between specialised Australian palliative and intensive care and the factors influencing a physician’s ability to manage deaths well. Method A qualitative investigation was focused on palliative and critical/acute settings. A thematic analysis was conducted on semi-structured in-depth interviews with 13 specialist physicians. Attention was given to eliciting meanings and experiences in Australian end-of-life care. Results Physicians negotiated multiple influences when managing dying patients and their families in the ICU. The way they understood and experienced end-of-life care practices was affected by cultural, institutional and professional considerations, and personal values and beliefs. Interpersonal and intrapsychic aspects highlighted the emotional and psychological relationship physicians have with patients and others. Many physicians were also unaware of what their cross-disciplinary colleagues could or could not do; poor professional recognition and collaboration, and ineffective care goal transition impaired their ability to assist good deaths. Experience was subject to the efficacy of physicians in negotiating complex bedside dynamics. Conclusions Regardless of specialty, all physicians identified the problematic nature of providing expert palliation in critical and acute settings. Strategies for integrating specialised palliative and intensive care were offered with corresponding directions for future research and clinical development. PMID:25147481

  2. 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

  3. Screening of multiparous women to avoid transfusion-related acute lung injury: a single centre experience.

    PubMed

    Sachs, U J H; Link, E; Hofmann, C; Wasel, W; Bein, G

    2008-12-01

    The aim of this study was to investigate which approach for serological testing of multiparous donors might be feasible and effective to reduce the risk of transfusion-related acute lung injury (TRALI). TRALI is a serious adverse event of blood transfusion. Antibodies to granulocytes and human leucocyte antigens (HLAs) are frequently detected in sera of implicated donors. These donors are often multiparous women. A general deferral of female plasma or screening strategies for leucocyte antibodies has been proposed to increase blood safety. A prospective study was initiated in 2003. Until 2006, serum samples from all female donors reporting three or more pregnancies (n = 229) were screened for the presence of antibodies against granulocytes and HLAs by immunofluorescence and agglutination tests as well as by a commercial HLA enzyme immunoassay. In total, 40% of all multiparous women were reactive in one of the assays. Twenty-nine percent of the reactive sera contained antibodies to granulocytes but not to HLAs. During the observation period, three TRALI reactions occurred in our hospital, two of which would have been prevented if the screening program had been extended to all previously pregnant donors. We conclude from these data that, not unexpectedly, the number of previous pregnancies is not a reliable indicator for the likelihood of inducing TRALI. More importantly, screening strategies for antibodies that might induce TRALI should probably not be reduced to HLA antibody screening. This finding awaits further research. PMID:19140817

  4. Upper Limb Ischemia: Clinical Experiences of Acute and Chronic Upper Limb Ischemia in a Single Center

    PubMed Central

    Bae, Miju; Chung, Sung Woon; Lee, Chung Won; Choi, Jinseok; Song, Seunghwan; Kim, Sang-pil

    2015-01-01

    Background Upper limb ischemia is less common than lower limb ischemia, and relatively few cases have been reported. This paper reviews the epidemiology, etiology, and clinical characteristics of upper limb ischemia and analyzes the factors affecting functional sequelae after treatment. Methods The records of 35 patients with acute and chronic upper limb ischemia who underwent treatment from January 2007 to December 2012 were retrospectively reviewed. Results The median age was 55.03 years, and the number of male patients was 24 (68.6%). The most common etiology was embolism of cardiac origin, followed by thrombosis with secondary trauma, and the brachial artery was the most common location for a lesion causing obstruction. Computed tomography angiography was the first-line diagnostic tool in our center. Twenty-eight operations were performed, and conservative therapy was implemented in seven cases. Five deaths (14.3%) occurred during follow-up. Twenty patients (57.1%) complained of functional sequelae after treatment. Functional sequelae were found to be more likely in patients with a longer duration of symptoms (odds ratio, 1.251; p=0.046) and higher lactate dehydrogenase (LDH) levels (odds ratio, 1.001; p=0.031). Conclusion An increased duration of symptoms and higher initial serum LDH levels were associated with the more frequent occurrence of functional sequelae. The prognosis of upper limb ischemia is associated with prompt and proper treatment and can also be predicted by initial serum LDH levels. PMID:26290835

  5. Acute lymphoblastic leukemia: A single center experience with Berlin, Frankfurt, and Munster-95 protocol

    PubMed Central

    Radhakrishnan, Venkatraman; Gupta, Sumant; Ganesan, Prasanth; Rajendranath, Rejiv; Ganesan, Trivadi S.; Rajalekshmy, Kamalalayan Raghavan; Sagar, Tenali Gnana

    2015-01-01

    Background: There is a paucity of data on the outcome following the treatment for acute lymphoblastic leukemia (ALL) from developing countries. Materials and Methods: Two hundred and thirty-eight consecutive patients with ALL <30 years of age diagnosed between January 2005 and December 2011 were analyzed retrospectively. Patients were treated modified Berlin, Frankfurt, and Munster 95 protocol. Event-free survival (EFS) was calculated using Kaplan–Meier survival analysis and variables were compared using log-rank test. Results: The EFS was 63.4% at a median follow-up was 32.7 months. On univariate analysis National Cancer Institute (NCI) risk stratification, sex, white blood cell count, day 8 blast clearance, and income were significantly associated with EFS. However, on multivariate analysis only female sex (P = 0.01) and day 8 blast clearance (P = 0.006) were significantly associated with EFS. Seventy-four of 238 (31%) patients had recurrent leukemia. The common sites of relapse were bone marrow in 55/74 (75%) patients and central nervous system in 11/74 (20%) patients. Conclusion: Compared to western data, there was an increased proportion of NCI high-risk patients and T-cell immunophenotype in our study. There has been an improvement in outcome of patients with ALL at our center over the last 2 decades. Female sex and clearance of blast in peripheral blood by day 8 of induction was associated with better EFS. PMID:26811597

  6. 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. PMID:27396627

  7. Attentional guidance by relative features: Behavioral and electrophysiological evidence.

    PubMed

    Schönhammer, Josef G; Grubert, Anna; Kerzel, Dirk; Becker, Stefanie I

    2016-07-01

    Our ability to select task-relevant information from cluttered visual environments is widely believed to be due to our ability to tune attention to the particular elementary feature values of a sought-after target (e.g., red, orange, yellow). By contrast, recent findings showed that attention is often tuned to feature relationships, that is, features that the target has relative to irrelevant features in the context (e.g., redder, yellower). However, the evidence for such a relational account is so far exclusively based on behavioral measures that do not allow a safe inference about early perceptual processes. The present study provides a critical test of the relational account, by measuring an electrophysiological marker in the EEG of participants (N2pc) in response to briefly presented distractors (cues) that could either match the physical features of the target or its relative features. In a first experiment, the target color and nontarget color were kept constant across trials. In line with a relational account, we found that only cues with the same relative color as the target were attended, regardless of whether the cues had the same physical color as the target. In a second experiment, we demonstrate that attention is biased to the exact target feature value when the target is embedded in a randomly varying context. Taken together, these results provide the first electrophysiological evidence that attention can modulate early perceptual processes differently; in a context-dependent manner versus a context-independent manner, resulting in marked differences in the range of colors that can attract attention. PMID:26990008

  8. Late Complications in acute Leukemia patients following HSCT: A single center experience

    PubMed Central

    Vaezi, Mohammad; Gharib, Cyrous; Souri, Maryam; Ghavamzadeh, Ardeshir

    2016-01-01

    Background: Hematopoietic stem cell transplantation (HSCT) is currently the only curative treatment for acute leukemia. As HSCT improves the long-term survival, it is necessary to assess the late-onset complications affecting the quality of life following HSCT. Subjects and Methods: The study included 122 patients (65 male, 57 female) with leukemia (72 AML and 50 ALL) who received transplants from fully- matched siblings, unrelated donors and unrelated cord blood donors between February 2013 and August 2014 in Shariati Hospital. All study participants were over 18 years of age and had the minimum and maximum survival of 2 and 5 years, respectively. Patients who received HLA-haploidentical SCT were excluded from the study. All allogeneic recipients received busulfan and cyclophosphamide as conditioning regimen. Nobody received TBI-based conditioning regimen in this study. Patients were evaluated for cardiovascular, vision, psychological, endocrine, fertility problems and secondary malignancies one year after transplantation. Results : Data were analyzed using SPSS 15.0. Mitral and tricuspid regurgitation (TR/MR) were the most common cardiac complications (n=12, 10.5%).Thirty-nine percent of patients had psychological problems, especially depression (34%). Cataract was observed in 13% of patients and 34% complained of dry eye. Symptomatic pulmonary changes were found in 13 patients (10.6%). None of the HSCT survivors had experienced fertility before study entry. According to LH and FSH levels, 15% and 9% of females had ovarian failure, respectively. Testosterone level was less than normal in 49(84%) men and, according to their FSH and LH level, 20 (41%) had secondary hypogonadism and 29 (59%) had primary gonadal dysfunction. Conclusion: The results showed that patients who received Bu/Cy conditioning regimen experienced fewer late side effects such as cataract formation and hypothyroidism, compared to previous studies using TBI-based conditioning regimen. PMID

  9. 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

  10. The impact of a new acute oncology service in acute hospitals: experience from the Clatterbridge Cancer Centre and Merseyside and Cheshire Cancer Network.

    PubMed

    Neville-Webbe, H L; Carser, J E; Wong, H; Andrews, J; Poulter, T; Smith, R; Marshall, E

    2013-12-01

    The 2008 National Confidential Enquiry into Patient Outcomes and Death highlighted an urgent need to improve the quality, safety and efficiency of care for cancer patients following emergency presentation to acute general hospitals. A network-wide acute oncology service (AOS) was therefore commissioned and implemented on the basis of recommendations from the National Chemotherapy Advisory Group (NCAG). Through a continuous programme of raising awareness regarding both the role of the AOS and the necessity of early patient referral to acute oncology teams, we have been able to establish an AOS across all acute trusts in our cancer network. The network-wide AOS has improved communication across clinical teams, enabled rapid review of over 3,000 patients by oncology staff, reduced hospital stay, increased understanding of oncology emergencies and their treatment, and enhanced pathways for rapid diagnosis and appropriate referrals for patients presenting with malignancy of undefined origin (MUO). These achievements have been made by developing a network protocol book for managing common oncology emergencies, by introducing local pathways for managing MUO and by collaborating with palliative care teams to introduce local acute oncology (AO) multi-disciplinary team (MDT) meetings. PMID:24298102

  11. Electrophysiologic characterization in spinocerebellar ataxia 17.

    PubMed

    Manganelli, F; Perretti, A; Nolano, M; Lanzillo, B; Bruni, A C; De Michele, G; Filla, A; Santoro, L

    2006-03-28

    The authors performed a multimodal electrophysiologic evaluation in nine patients belonging to four SCA17 (spinocerebellar ataxia type 17) families. Peripheral nerve and visual system were not involved. Brainstem auditory evoked potentials were constantly abnormal with central type lesions. Magnetic motor evoked potentials were abnormal only in the lower limbs, suggesting a length-dependent involvement of the pyramidal tract. Somatosensory evoked potentials were abnormal in almost all our patients, and abnormalities were consistent with a somatosensory pathway involvement along the brainstem. PMID:16567717

  12. To explore and understand the leadership experiences of modern matrons, within an acute NHS Trust.

    PubMed

    Lawrence, Nigel; Richardson, Janet

    2014-01-01

    Aim  The aim of this study was to explore and understand the leadership experiences of modern matrons. Background  Modern matrons were re-introduced to the National Health Service in 2002, and effective leadership has been identified as being essential for the role to be successful. However, there is minimal evidence of how modern matrons experience effective leadership. Methods  The study used a descriptive generic qualitative methodology; one-to-one semi-structured interviews were conducted with nine matrons. This was subjected to an inductive thematic analysis. Results  Three themes were found to influence modern matron's leadership experiences: leadership behaviours, negative influences and leadership investment. They did not follow one leadership style but adapted this to their situation. Various factors appeared to restrict their leadership effectiveness. Conclusions  The findings suggest that exposure to a range of leadership styles should be included in preparation and CPD for the modern matron role and a more consistent job description and job purpose should be developed. Implications for nursing management  Leadership styles such as transformational leadership alone do not meet the complex demands of nursing leaders, and therefore there is a requirement for greater flexibility in leadership development for all health care professionals. PMID:23410106

  13. Electrophysiological Properties of Dural Afferents in the Absence and Presence of Inflammatory Mediators

    PubMed Central

    Harriott, Andrea M.; Gold, Michael S.

    2009-01-01

    Migraine is a debilitating condition characterized by recurrent severe head pain. Although mechanisms underlying a migraine attack remain controversial, one proposal is that inflammatory mediator (IM)–induced activation and sensitization of dural afferents contribute to the initiation of migraine pain. We and others have shown that the electrophysiological properties of afferents, both in the absence and the presence of IM, vary as a function of target of innervation. These differences may account for unique aspects of pain syndromes associated with specific body regions. Therefore the purpose of the present study was to test the hypothesis that the electrophysiological properties of dural afferents differ from those innervating the temporalis muscle (TM), a structure in close proximity to the dura but that is not associated with pain syndromes at all similar to migraine. Acutely dissociated retrograde labeled primary afferents innervating the dura and TM were examined with whole cell current-clamp recordings. Passive and active electrophysiological properties were determined before and after the application of IM: (in μM) prostaglandin E2 (1), bradykinin (10), and histamine (1). In the absence of IM, there were significant differences between the two populations, particularly with respect to the response to suprathreshold stimulation where dural afferents were more excitable than TM afferents. Importantly, although both populations of afferents were sensitized by IM, the pattern of passive and active electrophysiological changes associated with IM-induced sensitization of these two populations of afferents suggested that there were both similarities and marked differences between the two with respect to underlying mechanisms of sensitization. If the differences between dural and TM afferents are due to a differential pattern of ion channel expression rather than differences in the relative density/biophysical properties of the same ion channels, it may be

  14. Protocol for electrophysiological monitoring of carotid endarterectomies

    PubMed Central

    Liu, Hong; Di Giorgio, Anthony M; Williams, Eric S; Evans, William; Russell, Michael J

    2010-01-01

    Near zero stroke rates can be achieved in carotid endarterectomy (CEA) surgery with selective shunting and electrophysiological neuromonitoring. though false negative rates as high as 40% have been reported. We sought to determine if improved training for interpretation of the monitoring signals can advance the efficacy of selective shunting with electrophysiological monitoring across multiple centers, and determine if other factors could contribute to the differences in reports. Processed and raw beta band (12.5-30 Hz) electroencephalogram (EEG) and median and tibial nerve somatosensory evoked potentials (SSEP) were monitored in 668 CEA cases at six surgical centers. A decrease in amplitude of 50% or more in any EEG or SSEP channel was the criteria for shunting or initiating a neuroprotective protocol. A reduction of 50% or greater in the beta band of the EEG or amplitude of the SSEP was observed in 150 cases. No patient showed signs of a cerebral infarct after surgery. Selective shunting based on EEG and SSEP monitoring can reduce CEA intraoperative stroke rate to a near zero level if trained personnel adopted standardized protocols. We also found that the rapid administration of a protective stroke protocol by attending anesthesiologists was an important aspect of this success rate. PMID:23554663

  15. Cellular cardiac electrophysiology modeling with Chaste and CellML

    PubMed Central

    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. PMID:25610400

  16. 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. PMID:25610400

  17. 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

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

    PubMed

    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

  19. 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. PMID:23207550

  20. 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

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

    PubMed

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

    2014-12-01

    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 quantum dot-coated glass pipettes that provide strong two-photon contrast at deeper penetration depths than those achievable with current methods. We demonstrated the pipettes' utility in targeted patch-clamp recording experiments and single-cell electroporation of identified rat and mouse neurons in vitro and in vivo. PMID:25326662

  2. Fast Left Prefrontal rTMS Acutely Suppresses Analgesic Effects of Perceived Controllability on the Emotional Component of Pain Experience

    PubMed Central

    Borckardt, Jeffrey J.; Reeves, Scott T.; Frohman, Heather; Madan, Alok; Jensen, Mark P.; Patterson, David; Barth, Kelly; Smith, A. Richard; Gracely, Richard; George, Mark S.

    2010-01-01

    The prefrontal cortex may be a promising target for transcranial magnetic stimulation (TMS) in the management of pain. It is not clear how prefrontal TMS affects pain perception, but previous findings suggest that ventral lateral and medial prefrontal circuits may comprise an important part of a circuit of ‘perceived controllability’ regarding pain, stress and learned helplessness. While the left dorsolateral prefrontal cortex is a common TMS target for treating clinical depression as well as modulating pain, little is known about whether TMS over this area may affect perceived controllability. The present study explored the immediate effects of fast TMS over the left dorsolateral prefrontal cortex on the analgesic effects of perceived pain controllability. Twenty-four healthy volunteers underwent a laboratory pain task designed to manipulate perception of pain controllability. Real TMS, compared to sham, suppressed the analgesic benefits of perceived-control on the emotional dimension of pain, but not the sensory/discriminatory dimension. Findings suggest that, at least acutely, fast TMS over the left dorsolateral prefrontal cortex may interrupt the perceived-controllability effect on the emotional dimension of pain experience. While it is not clear whether this cortical area is directly involved with modulating perceived controllability or whether downstream effects are responsible for the present findings, it appears possible that left dorsolateral prefrontal TMS may produce analgesic effects by acting through a cortical ‘perceived control’ circuit regulating limbic and brainstem areas of the pain circuit. PMID:21122992

  3. 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

  4. M-sequences in ophthalmic electrophysiology.

    PubMed

    Müller, Philipp L; Meigen, Thomas

    2016-01-01

    The aim of this review is to use the multimedia aspects of a purely digital online publication to explain and illustrate the highly capable technique of m-sequences in multifocal ophthalmic electrophysiology. M-sequences have been successfully applied in clinical routines during the past 20 years. However, the underlying mathematical rationale is often daunting. These mathematical properties of m-sequences allow one not only to separate the responses from different fields but also to analyze adaptational effects and impacts of former events. By explaining the history, the formation, and the different aspects of application, a better comprehension of the technique is intended. With this review we aim to clarify the opportunities of m-sequences in order to motivate scientists to use m-sequences in their future research. PMID:26818968

  5. Electrophysiology of the chemically sympathectomised dog.

    PubMed

    Godin, D; Guimond, C; Nadeau, R A; Leblanc, A R

    1982-09-01

    The contribution of the sympathetic nervous system in the definition of various electrophysiological variables was studied in chemically sympathectomised dogs. Chemical sympathectomy was obtained following intravenous injection of 50 mg X kg-1 of 6-hydroxydopamine. Sympathectomised dogs presented significant increases in: basic sinus period, sino-atrial conduction time (SACT), AH and HV intervals of the His bundle electrogram, atrial functional (AFRP) and effective (AERP) refractory periods, atrio-ventricular node functional (AVNFRP) and effective (AVNERP) refractory periods, ventricular functional (VFRP) and effective (EVRP) refractory periods and atrial (AMAP) and ventricular (VMAP) monophasic action potential durations. Corrected sinus recovery time (CSRT) was not affected by chemical sympathectomy. Neither was the atrial ERP/MAP duration ratio. This new form of sympathectomy affects all the levels of the cardiac conduction system. Such results are in accordance with those obtained with surgical sympathectomy or the use of beta-blocking agents. PMID:6816469

  6. 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

  7. [Biofeedback in psychomotor training. Electrophysiological bases].

    PubMed

    Bazanova, O M; Mernaia, E M; Shtark, M B

    2008-05-01

    Comparison of influence of usual musical practice and the same trainings but using biofeedback on electrophysiological and psychological markers of optimal psychomotor functioning in 39 students-musicians revealed that the obvious musical practice caused psychomotor pressure in most students (with initially low individual alpha peak frequency), whereas similar practice combined with an individualized session of alpha-EEG/EMG biofeedback was accompanied by increase of alpha-activity in all examinees and a decrease (reduction) of integrated EMG that indicated reaching of optimal psychomotor functioning. It appears that the psychomotor learning ability depends on the baseline individual alpha-activity. Individual alpha peak frequency was associated with fluency and efficiency of psychomotor performance, individual alpha band width--with plasticity and creativity, individual amount of alpha suppression in response to opening eyes--with the level of selfactualization. These alpha activity EEG indices correlated with efficiency of the biofeedback training. PMID:18669359

  8. 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.

  9. Cardiovascular Imaging in the Electrophysiology Laboratory.

    PubMed

    Sanchis, Laura; Prat, Susanna; Sitges, Marta

    2016-06-01

    In recent years, rapid technological advances have allowed the development of new electrophysiological procedures that would not have been possible without the parallel development of imaging techniques used to plan and guide these procedures and monitor their outcomes. Ablation of atrial fibrillation is among the interventions with the greatest need for imaging support. Echocardiography allows the appropriate selection of patients and the detection of thrombi that would contraindicate the intervention; cardiac magnetic resonance imaging and computed tomography are also essential in planning this procedure, by allowing a detailed anatomical study of the pulmonary veins. In addition, in cardiac resynchronization therapy, echocardiography plays a central role in both patient selection and, later, in device adjustment and in assessing the effectiveness of the technique. More recently, ablation of ventricular tachycardias has been established as a treatment option; this would not be possible without planning using an imaging study such as cardiac magnetic resonance imaging of myocardial scarring. PMID:27107802

  10. Differential aspects of the disease and treatment of Thoracic Acute Aortic Dissection (TAAD)-the European experience.

    PubMed

    Pepper, John

    2016-07-01

    The management of patients with acute aortic dissection continues to be a challenge. It is an uncommon but lethal condition which continues to be under-diagnosed and under-treated. In this review, the term acute aortic syndrome is preferred in order to embrace the closely related pathologies of intramural hematoma (IMH) and penetrating aortic ulcer (PAU). PMID:27563549

  11. Differential aspects of the disease and treatment of Thoracic Acute Aortic Dissection (TAAD)—the European experience

    PubMed Central

    2016-01-01

    The management of patients with acute aortic dissection continues to be a challenge. It is an uncommon but lethal condition which continues to be under-diagnosed and under-treated. In this review, the term acute aortic syndrome is preferred in order to embrace the closely related pathologies of intramural hematoma (IMH) and penetrating aortic ulcer (PAU). PMID:27563549

  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. PMID:23625905

  13. Electrophysiological and behavioral phenotype of insulin receptor defective mice

    PubMed Central

    Das, P.; Parsons, A.D.; Scarborough, J.; Hoffman, J.; Wilson, J.; Thompson, R.N.; Overton, J.M.; Fadool, D.A.

    2009-01-01

    The olfactory bulb expresses one of the highest levels of insulin found in the brain. A high level of expression of the concomitant insulin receptor (IR) kinase is also retained in this brain region, even in the adult. We have previously demonstrated in a heterologous system that insulin modulates the voltage-dependent potassium channel, Kv1.3, through tyrosine phosphorylation of three key residues in the amino and carboxyl terminus of the channel protein. Phosphorylation also induces current suppression of the Kv1.3-contributed current in cultured olfactory bulb neurons (OBNs) of rodents. In order to explore the behavioral importance of this kinase-induced modulation of the channel for the olfactory ability of the animal, mice with a targeted-gene deletion of the insulin receptor were electrophysiologically and behaviorally characterized. Mice heterozygous for the insulin receptor kinase (IR+/−) gene performed the same as wild-type (+/+) mice when challenged with a traditional, non-learning-based task to test gross anosmia. There was also no significant difference across the two genotypes in tests designed to measure exploratory behavior or in a battery of systems physiology experiments designed to assess metabolic energy usage (locomotion, ingestive behaviors, weight, oxygen consumption, and respiratory quotient). Object memory recognition tests suggest that IR+/− mice have an impairment in recognition of familiarized objects; IR+/− mice demonstrate poor performance for both short-term (1 h) and long-term (24 h) memory tests in comparison to that of wild-type mice. Electrophysiological experiments indicate that mitral cell neurons cultured from both heterozygous and homozygous-null mice (IR+/− and IR−/−) have an decreased peak current amplitude compared with that recorded for wild-type (+/+) animals matched for days in vitro (DIV). These data indicate that the loss of one allele of the IR kinase gene modifies the electrical phenotype of the mitral

  14. The electrophysiology of the beta-cell based on single transmembrane protein characteristics.

    PubMed

    Meyer-Hermann, Michael E

    2007-10-15

    The electrophysiology of beta-cells is at the origin of insulin secretion. beta-Cells exhibit a complex behavior upon stimulation with glucose including repeated bursts and continuous spiking. Mathematical modeling is most suitable to improve knowledge about the function of various transmembrane currents provided the model is based on reliable data. This is the first attempt to build a mathematical model for the beta-cell electrophysiology in a bottom-up approach that relies on single protein conductance data. The results of previous whole-cell-based models are reconsidered. The full simulation including all prominent transmembrane proteins in beta-cells is used to provide a functional interpretation of their role in beta-cell bursting and an updated vantage point of beta-cell electrophysiology. As a result of a number of in silico knock-out and block experiments the novel model makes some unexpected predictions: single-channel conductance data imply that large-conductance calcium-gated potassium currents acquire the potential of driving oscillations at supralarge glucose levels. A more complex burst interruption model is presented. It also turns out that, depending on the species, sodium currents may be more relevant than considered so far. Experiments are proposed to verify these predictions. PMID:17573431

  15. Optical stimulation enables paced electrophysiological studies in embryonic hearts

    PubMed Central

    Wang, Yves T.; Gu, Shi; Ma, Pei; Watanabe, Michiko; Rollins, Andrew M.; Jenkins, Michael W.

    2014-01-01

    Cardiac electrophysiology plays a critical role in the development and function of the heart. Studies of early embryonic electrical activity have lacked a viable point stimulation technique to pace in vitro samples. Here, optical pacing by high-precision infrared stimulation is used to pace excised embryonic hearts, allowing electrophysiological parameters to be quantified during pacing at varying rates with optical mapping. Combined optical pacing and optical mapping enables electrophysiological studies in embryos under more physiological conditions and at varying heart rates, allowing detection of abnormal conduction and comparisons between normal and pathological electrical activity during development in various models. PMID:24761284

  16. Obstetric Acute Kidney Injury; A Three Year Experience at a Medical College Hospital in North Karnataka, India

    PubMed Central

    Lakshmi, K.S.; Gorikhan, Gousia; M.M., Umadi; S.T., Kalsad; M.P., Madhavaranga; Dambal, Amrut; Padaki, Samata

    2015-01-01

    Introduction: Acute kidney injury is a rare and sometimes fatal complication of pregnancy, the incidence of which has been declining worldwide, though still high in developing countries. There are recent observations of increasing incidence in some developed countries attributed to hypertensive disorders of pregnancy. Materials and Methods: In this study, we have analysed the records of all patients referred to the dialysis unit of a medical college hospital in Karnataka for acute kidney injury related to pregnancy. AKIN (Acute Kidney Injury Network) criteria for the diagnosis of acute kidney injury were adapted. Age, parity, gestational age, causative factors for acute kidney injury, mode of delivery, access to antenatal care, operative procedures, blood component transfusions, number of haemodialysis, time for initiation of haemodialysis, duration of hospital stay and mortality were analysed by finding mean, standard deviation and standard error. Results: Fifteen patients out of 21563 who delivered in our hospital developed acute kidney injury. These (n=15) were out of 149 patients of acute kidney injury of various aetiologies who underwent haemodialysis between 2012 and 2014. Of these two were unregistered for antenatal care. Ten were multiparous, Eleven were from rural background, one had home delivery, six had vaginal delivery, seven had caesarean section and two had second trimester abortion. Placental abruption with intrauterine death was the commonest Cause in 9 out of 15 cases. All had severe anaemia. Patients received a mean of 3.9 (SD+/- 2.4) sessions of haemodialysis. Eleven patients recovered completely, two died and two left against medical advice. Conclusion: Obstetric acute kidney injury is associated with poor access to antenatal care, multiparity and rural background. Placental abruption is the commonest cause of obstetric acute kidney injury. Blood component transfusions, avoidance of nephrotoxic drugs and early initiation of haemodialysis are

  17. 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. PMID:26203105

  18. The First Egyptian Experience Using New Self-Expandable Metal Stents in Acute Esophageal Variceal Bleeding: Pilot Study

    PubMed Central

    Zakaria, Mohamed S.; Hamza, Iman M.; Mohey, Mohamed A.; Hubamnn, Rainer G.

    2013-01-01

    Background/Aim: Balloon tamponade has been widely available in emergency situations of acute variceal bleeding. To lessen the complications of Balloon tamponade, a new special type of stent for exclusive use in acute variceal bleeding has been developed. This study aims to investigate the effectiveness and safety of the new self-expandable metal stents (SEMS) in the initial control of acute variceal bleeding. We also hypothesized that using SEMS can bridge the acute bleeding episode converting endoscopic management by sclerotherapy or band ligation to an elective procedure. Patients and Methods: Twenty patients with acute variceal bleeding were included in the study and 16 of them were allocated to receive stent treatment. Results: Stent deployment was successful in 15 of 16 patients (93.75%). Technical errors were reported in 3 (18.75%) patients. Initial control of variceal bleeding was reported in 14 (out of 16) (87.5%) patients. The mean duration of the procedure was 10 (±6) min. Mortality was reported in 4 (25.0%) patients. Conclusion: SEMS is a safe and effective mean to control acute variceal bleeding. PMID:23828748

  19. ELECTROPHYSIOLOGICAL SYSTEMS FOR NEUROTOXICITY FIELD TESTING: PEARL II AND ALTERNATIVES

    EPA Science Inventory

    Pearl II, a computerized battery of electrophysiological tests designed for neurotoxicity field testing, was developed a decade ago. he battery includes sensory evoked potentials (auditory, somatosensory and visual), event related slow brain potentials (CNV,P30O), and associated ...

  20. 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. PMID:21600993

  1. Impact of subanesthetic doses of ketamine on AMPA-mediated responses in rats: An in vivo electrophysiological study on monoaminergic and glutamatergic neurons

    PubMed Central

    El Iskandrani, Kareem S; Oosterhof, Chris A; Blier, Pierre

    2015-01-01

    The rapid antidepressant action of a subanesthetic dose of ketamine in treatment-resistant patients represents the most striking recent breakthrough in the understanding of the antidepressant response. Evidence demonstrates tight interactions between the glutamatergic and monoaminergic systems. It is thus hypothesized that monoamine systems may play a role in the immediate/rapid effects of ketamine. In vivo electrophysiological recordings were carried in male rats following ketamine administration (10 and 25 mg/kg, i.p.) to first assess its effects on monoaminergic neuron firing. In a second series of experiments, the effects of ketamine administration on α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)- and N-methyl-D-aspartate receptor (NMDA)-evoked responses in hippocampus CA3 pyramidal neurons were also investigated using micro-iontophoretic applications. Although acute (~2 hours) ketamine administration did not affect the mean firing activity of dorsal raphe serotonin and ventral tegmental area dopamine neurons, it did increase that of locus coeruleus norepinephrine neurons. In the latter brain region, while ketamine also enhanced bursting activity, it did increase population activity of dopamine neurons in the ventral tegmental area. These effects of ketamine were prevented by the prior administration of the AMPA receptor antagonist 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[f]quinoxaline-7-sulfonamide. An increase in AMPA-evoked response of CA3 pyramidal neurons was also observed 30 minutes following acute ketamine administration. The present findings suggest that acute ketamine administration produces a rapid enhancement of catecholaminergic neurons firing activity through an amplification of AMPA transmission. These effects may play a crucial role in the antidepressant effects of ketamine observed shortly following its infusion in depressed patients. PMID:25759403

  2. 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

  3. 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. PMID:26926652

  4. 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.

  5. Electrophysiological correlates of observational learning in children.

    PubMed

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

    2016-09-01

    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 individual and observational reinforcement learning in 8- to 10-year-old children. Specifically, we manipulated the amount of observable information as well as children's similarity in age to the observed person (same-aged child vs. adult) to examine the effects of similarity in age on the integration of observed information in children. We show that the feedback-related negativity (FRN) during individual reinforcement learning reflects the valence of outcomes of own actions. Furthermore, we found that the feedback-related negativity during observational reinforcement learning (oFRN) showed a similar distinction between outcome valences of observed actions. This suggests that the oFRN can serve as a measure of observational learning in middle childhood. Moreover, during observational learning children profited from the additional social information and imitated the choices of their own peers more than those of adults, indicating that children have a tendency to conform more with similar others (e.g. their own peers) compared to dissimilar others (adults). Taken together, our results show that children can benefit from integrating observable information and that oFRN may serve as a measure of observational learning in children. PMID:26074422

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

    PubMed

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

    2010-02-01

    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. PMID:19853009

  7. Electrophysiological study in neuromuscular junction disorders.

    PubMed

    Cherian, Ajith; Baheti, Neeraj N; Iype, Thomas

    2013-01-01

    This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation. PMID:23661960

  8. Closed-Loop, Open-Source Electrophysiology

    PubMed Central

    Rolston, John D.; Gross, Robert E.; Potter, Steve M.

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  9. Cardiovascular magnetic resonance guided electrophysiology studies

    PubMed Central

    Kolandaivelu, Aravindan; Lardo, Albert C; Halperin, Henry R

    2009-01-01

    Catheter ablation is a first line treatment for many cardiac arrhythmias and is generally performed under x-ray fluoroscopy guidance. However, current techniques for ablating complex arrhythmias such as atrial fibrillation and ventricular tachycardia are associated with suboptimal success rates and prolonged radiation exposure. Pre-procedure 3D CMR has improved understanding of the anatomic basis of complex arrhythmias and is being used for planning and guidance of ablation procedures. A particular strength of CMR compared to other imaging modalities is the ability to visualize ablation lesions. Post-procedure CMR is now being applied to assess ablation lesion location and permanence with the goal of indentifying factors leading to procedure success and failure. In the future, intra-procedure real-time CMR, together with the ability to image complex 3-D arrhythmogenic anatomy and target additional ablation to regions of incomplete lesion formation, may allow for more successful treatment of even complex arrhythmias without exposure to ionizing radiation. Development of clinical grade CMR compatible electrophysiology devices is required to transition intra-procedure CMR from pre-clinical studies to more routine use in patients. PMID:19580654

  10. Closed-loop, open-source electrophysiology.

    PubMed

    Rolston, John D; Gross, Robert E; Potter, Steve M

    2010-01-01

    Multiple extracellular microelectrodes (multi-electrode arrays, or MEAs) effectively record rapidly varying neural signals, and can also be used for electrical stimulation. Multi-electrode recording can serve as artificial output (efferents) from a neural system, while complex spatially and temporally targeted stimulation can serve as artificial input (afferents) to the neuronal network. Multi-unit or local field potential (LFP) recordings can not only be used to control real world artifacts, such as prostheses, computers or robots, but can also trigger or alter subsequent stimulation. Real-time feedback stimulation may serve to modulate or normalize aberrant neural activity, to induce plasticity, or to serve as artificial sensory input. Despite promising closed-loop applications, commercial electrophysiology systems do not yet take advantage of the bidirectional capabilities of multi-electrodes, especially for use in freely moving animals. We addressed this lack of tools for closing the loop with NeuroRighter, an open-source system including recording hardware, stimulation hardware, and control software with a graphical user interface. The integrated system is capable of multi-electrode recording and simultaneous patterned microstimulation (triggered by recordings) with minimal stimulation artifact. The potential applications of closed-loop systems as research tools and clinical treatments are broad; we provide one example where epileptic activity recorded by a multi-electrode probe is used to trigger targeted stimulation, via that probe, to freely moving rodents. PMID:20859448

  11. 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

  12. [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. PMID:22188891

  13. Electrophysiological study of myoclonus in pediatric practice.

    PubMed

    Oguro, K; Kobayashi, J; Aiba, H; Kobayashi, S; Hojo, H

    1998-06-01

    Myoclonus can be caused from a variety of central nervous system disorders. With regard to its pathophysiology, much work has been done in adult patients, but reports from pediatric clinics are scarce. We describe the clinical and electrophysiological features of four different types of myoclonus in children using back averaging technique. In a patient with cortical reflex myoclonus, myoclonic jerks were induced in the distal right arm by taps on the ipsilateral fingers. Myoclonus was preceded by the cortical spike which was localized posterior to the central sulcus contralateral to the myoclonus, and the cortical spike was time-locked to the myoclonus. In a patient with subcortico-cortical myoclonus, myoclonus occurred as a focal motor seizure. Myoclonic jerks were preceded by generalized cortical waves which were of maximal amplitude over the cortex contralateral to the myoclonus, and cortical waves time-locked to the myoclonus. A patient with spinal myoclonus had rhythmical and segmental myoclonus. Myoclonus was induced in both arms after electrical stimulation at the wrist with a latency which was slightly longer than that of the F wave. In a patient with brainstem myoclonus, muscle activity was bilaterally synchronous and was predominant in the proximal flexors. The pattern of muscle recruitment suggested that the myoclonus signal travelled downward along the spinal cord and upward through the brainstem. The back averaging technique is essential in the differential diagnosis of myoclonus. PMID:9651693

  14. 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.

  15. Electrophysiological responses of the Naupactus bipes beetle to essential oils from Piperaceae species.

    PubMed

    Ramos, Clécio S; Soares, Marisi G; da Silva, Adalberto M; Batista-Pereira, Luciane G; Corrêa, Arlene G; Kato, Massuo J

    2012-08-01

    Electrophysiological responses based on electroantennographic detection (GC-EAD) and electroantennography (EAG) analysis of Naupactus bipes beetles (Germar, 1824) (Coleoptera: Curculionidae: Brachycerinae) were used to test volatile oils of Piper gaudichaudianum, P. regnellii and P. hispidum. In the EAG experiments, female and male beetles showed significant EAG response to the three volatile oils of Piper species, with the females' responses slightly higher than the males'. The experiments with GC-EAD revealed that some terpenoids (namely, alpha-pinene, beta-pinene, myrcene, alpha-copaene and germacrene) present in the leaf essential oils of the Piper species are perceptible to female and male beetles. PMID:22978240

  16. 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.

  17. LBM-EP: Lattice-Boltzmann method for fast cardiac electrophysiology simulation from 3D images.

    PubMed

    Rapaka, S; Mansi, T; Georgescu, B; Pop, M; Wright, G A; Kamen, A; Comaniciu, Dorin

    2012-01-01

    Current treatments of heart rhythm troubles require careful planning and guidance for optimal outcomes. Computational models of cardiac electrophysiology are being proposed for therapy planning but current approaches are either too simplified or too computationally intensive for patient-specific simulations in clinical practice. This paper presents a novel approach, LBM-EP, to solve any type of mono-domain cardiac electrophysiology models at near real-time that is especially tailored for patient-specific simulations. The domain is discretized on a Cartesian grid with a level-set representation of patient's heart geometry, previously estimated from images automatically. The cell model is calculated node-wise, while the transmembrane potential is diffused using Lattice-Boltzmann method within the domain defined by the level-set. Experiments on synthetic cases, on a data set from CESC'10 and on one patient with myocardium scar showed that LBM-EP provides results comparable to an FEM implementation, while being 10 - 45 times faster. Fast, accurate, scalable and requiring no specific meshing, LBM-EP paves the way to efficient and detailed models of cardiac electrophysiology for therapy planning. PMID:23286029

  18. The Sound of Feelings: Electrophysiological Responses to Emotional Speech in Alexithymia

    PubMed Central

    Goerlich, Katharina Sophia; Aleman, André; Martens, Sander

    2012-01-01

    Background Alexithymia is a personality trait characterized by difficulties in the cognitive processing of emotions (cognitive dimension) and in the experience of emotions (affective dimension). Previous research focused mainly on visual emotional processing in the cognitive alexithymia dimension. We investigated the impact of both alexithymia dimensions on electrophysiological responses to emotional speech in 60 female subjects. Methodology During unattended processing, subjects watched a movie while an emotional prosody oddball paradigm was presented in the background. During attended processing, subjects detected deviants in emotional prosody. The cognitive alexithymia dimension was associated with a left-hemisphere bias during early stages of unattended emotional speech processing, and with generally reduced amplitudes of the late P3 component during attended processing. In contrast, the affective dimension did not modulate unattended emotional prosody perception, but was associated with reduced P3 amplitudes during attended processing particularly to emotional prosody spoken in high intensity. Conclusions Our results provide evidence for a dissociable impact of the two alexithymia dimensions on electrophysiological responses during the attended and unattended processing of emotional prosody. The observed electrophysiological modulations are indicative of a reduced sensitivity to the emotional qualities of speech, which may be a contributing factor to problems in interpersonal communication associated with alexithymia. PMID:22615853

  19. Mapping of cardiac electrophysiology onto a dynamic patient-specific heart model.

    PubMed

    Wilson, Kevin; Guiraudon, Gerard; Jones, Douglas L; Peters, Terry M

    2009-12-01

    Electrophysiological cardiac data mapping is an essential tool for the study of cardiac rhythm disorders, such as atrial fibrillation. Over the past decade, various advanced cardiac mapping systems have been developed to create detailed cardiac maps and assist physicians in diagnosis and therapy guidance. While these systems have increased the ability to study and treat cardiac arrhythmias, inherent limitations exist. The objective of this paper is to describe and evaluate a system that extends current approaches to cardiac mapping, to create a dynamic cardiac map, using patient-specific cardiac models. This paper details novel approaches to collecting a stream of electrophysiological cardiac data, registering the data with patient-specific dynamic cardiac models, and displaying the data directly on the dynamic model surface, giving a more accurate and comprehensive visualization environment when compared to current systems. To validate the system, a series of laboratory and in vivo experiments were conducted. In the laboratory studies, the system was used to test the user's ability to accurately locate a landmark in physical space, as well as their ability to accurately navigate to a virtual location. In the in vivo studies the overall system performance was compared to an existing electrophysiological recording system, where right atrial cardiac maps were created during sinus and paced cardiac rhythms. The results showed that the new dynamic cardiac mapping system was able to maintain high accuracy in locating physical and virtual landmarks, while being able to create a dynamic cardiac map displayed on a dynamic cardiac surface model. PMID:19423433

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

    NASA Astrophysics Data System (ADS)

    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.

    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 für 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.

  1. Rabbit-Specific Ventricular Model of Cardiac Electrophysiological Function including Specialized Conduction System

    PubMed Central

    Bordas, R.; Gillow, K.; Lou, Q.; Efimov, I. R.; Gavaghan, D.; Kohl, P.; Grau, V.; Rodriguez, B.

    2011-01-01

    The function of the ventricular specialized conduction system in the heart is to ensure the coordinated electrical activation of the ventricles. It is therefore critical to the overall function of the heart, and has also been implicated as an important player in various diseases, including lethal ventricular arrhythmias such as ventricular fibrillation and drug-induced torsades de pointes. However, current ventricular models of electrophysiology usually ignore, or include highly simplified representations of the specialized conduction system. Here, we describe the development of a image-based, species-consistent, anatomically-detailed model of rabbit ventricular electrophysiology that incorporates a detailed description of the free-running part of the specialized conduction system. Techniques used for the construction of the geometrical model of the specialized conduction system from a magnetic resonance dataset and integration of the system model into a ventricular anatomical model, developed from the same dataset, are described. Computer simulations of rabbit ventricular electrophysiology are conducted using the novel anatomical model and rabbit-specific membrane kinetics to investigate the importance of the components and properties of the conduction system in determining ventricular function under physiological conditions. Simulation results are compared to panoramic optical mapping experiments for model validation and results interpretation. Full access is provided to the anatomical models developed in this study. PMID:21672547

  2. 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

  3. Electrophysiological CNS-processes related to associative learning in humans.

    PubMed

    Christoffersen, Gert R J; Schachtman, Todd R

    2016-01-01

    The neurophysiology of human associative memory has been studied with electroencephalographic techniques since the 1930s. This research has revealed that different types of electrophysiological processes in the human brain can be modified by conditioning: sensory evoked potentials, sensory induced gamma-band activity, periods of frequency-specific waves (alpha and beta waves, the sensorimotor rhythm and the mu-rhythm) and slow cortical potentials. Conditioning of these processes has been studied in experiments that either use operant conditioning or repeated contingent pairings of conditioned and unconditioned stimuli (classical conditioning). In operant conditioning, the appearance of a specific brain process is paired with an external stimulus (neurofeedback) and the feedback enables subjects to obtain varying degrees of control of the CNS-process. Such acquired self-regulation of brain activity has found practical uses for instance in the amelioration of epileptic seizures, Autism Spectrum Disorders (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). It has also provided communicative means of assistance for tetraplegic patients through the use of brain computer interfaces. Both extra and intracortically recorded signals have been coupled with contingent external feedback. It is the aim for this review to summarize essential results on all types of electromagnetic brain processes that have been modified by classical or operant conditioning. The results are organized according to type of conditioned EEG-process, type of conditioning, and sensory modalities of the conditioning stimuli. PMID:26367470

  4. A low-cost, open-source, wireless electrophysiology system.

    PubMed

    Ghomashchi, A; Zheng, Z; Majaj, N; Trumpis, M; Kiorpes, L; Viventi, J

    2014-01-01

    Many experiments in neuroscience require or would benefit tremendously from a wireless neural recording system. However, commercially available wireless systems are expensive, have moderate to high noise and are often not customizable. Academic wireless systems present impressive capabilities, but are not available for other labs to use. To overcome these limitations, we have developed an ultra-low noise 8 channel wireless electrophysiological data acquisition system using standard, commercially available components. The system is capable of recording many types of neurological signals, including EEG, ECoG, LFP and unit activity. With a diameter of just 25 mm and height of 9 mm, including a CR2032 Lithium coin cell battery, it is designed to fit into a small recording chamber while minimizing the overall implant height (Fig. 1 and 3). Using widely available parts we were able to keep the material cost of our system under $100 dollars. The complete design, including schematic, PCB layout, bill of materials and source code, will be released through an open source license, allowing other labs to modify the design to fit their needs. We have also developed a driver to acquire data using the BCI2000 software system. Feedback from the community will allow us to improve the design and create a more useful neuroscience research tool. PMID:25570656

  5. Electrophysiological Signature of Homomeric and Heteromeric Glycine Receptor Channels.

    PubMed

    Raltschev, Constanze; Hetsch, Florian; Winkelmann, Aline; Meier, Jochen C; Semtner, Marcus

    2016-08-19

    Glycine receptors are chloride-permeable, ligand-gated ion channels and contribute to the inhibition of neuronal firing in the central nervous system or to facilitation of neurotransmitter release if expressed at presynaptic sites. Recent structure-function studies have provided detailed insights into the mechanisms of channel gating, desensitization, and ion permeation. However, most of the work has focused only on comparing a few isoforms, and among studies, different cellular expression systems were used. Here, we performed a series of experiments using recombinantly expressed homomeric and heteromeric glycine receptor channels, including their splice variants, in the same cellular expression system to investigate and compare their electrophysiological properties. Our data show that the current-voltage relationships of homomeric channels formed by the α2 or α3 subunits change upon receptor desensitization from a linear to an inwardly rectifying shape, in contrast to their heteromeric counterparts. The results demonstrate that inward rectification depends on a single amino acid (Ala(254)) at the inner pore mouth of the channels and is closely linked to chloride permeation. We also show that the current-voltage relationships of glycine-evoked currents in primary hippocampal neurons are inwardly rectifying upon desensitization. Thus, the alanine residue Ala(254) determines voltage-dependent rectification upon receptor desensitization and reveals a physio-molecular signature of homomeric glycine receptor channels, which provides unprecedented opportunities for the identification of these channels at the single cell level. PMID:27382060

  6. Acute stress and hippocampal output: exploring dorsal CA1 and subicular synaptic plasticity simultaneously in anesthetized rats

    PubMed Central

    MacDougall, Matthew J; Howland, John G

    2013-01-01

    The Cornu Ammonis-1 (CA1) subfield and subiculum (SUB) serve as major output structures of the hippocampal formation. Exploring forms of synaptic plasticity simultaneously within these two output regions may improve understanding of the dynamics of hippocampal circuitry and information transfer between hippocampal and cortical brain regions. Using a novel dual-channel electrophysiological preparation in urethane-anesthetized adult male Sprague-Dawley rats in vivo, we examined the effects of acute restraint stress (30 min) on short- and long-term forms of synaptic plasticity in both CA1 and SUB by stimulating the CA3 region. Paired-pulse facilitation was disrupted in SUB but not CA1 in the dual-channel experiments following exposure to acute stress. Disruptions in CA1 PPF were evident in subsequent single-channel experiments with a more anterior recording site. Acute stress disrupted long-term potentiation induced by high-frequency stimulation (10 bursts of 20 pulses at 200 Hz) in both CA1 and SUB. Low-frequency stimulation (900 pulses at 1 Hz) did not alter CA1 plasticity while a late-developing potentiation was evident in SUB that was disrupted following exposure to acute stress. These findings highlight differences in the sensitivity to acute stress for distinct forms of synaptic plasticity within synapses in hippocampal output regions. The findings are discussed in relation to normal and aberrant forms of hippocampal-cortical information processing. PMID:24303119

  7. Fate of Central Venous Catheters Used for Acute Extracorporeal Treatment in Critically Ill Pediatric Patients: A Single Center Experience.

    PubMed

    Rus, Rina R; Premru, Vladimir; Novljan, Gregor; Grošelj-Grenc, Mojca; Ponikvar, Rafael

    2016-06-01

    Renal replacement treatment (RRT) is required in severe acute kidney injury, and a functioning central venous catheter (CVC) is crucial. Twenty-eight children younger than 16 years have been treated at the University Medical Centre Ljubljana between 2003 and 2012 with either acute hemodialysis (HD) and/or plasma exchange (PE), and were included in our study. The age of the patients ranged from 2 days to 14.1 years. Sixty-six CVCs were inserted (52% de novo, 48% guide wire). The sites of insertion were the jugular vein in 20% and the femoral vein in 80%. Catheters were in function from 1 day to 27 days. The most common cause for CVC removal or exchange was catheter dysfunction (50%). CVCs were mostly inserted in the femoral vein, which is the preferred site of insertion in acute HD/PE because of the smaller number of complications. PMID:27312920

  8. Outcomes associated with nesiritide administration for acute decompensated heart failure in the emergency department observation unit: a single center experience.

    PubMed

    Styron, Joseph F; Jois-Bilowich, Preeti; Tallman, Thomas; Emerman, Charles; Starling, Randall C; Frank Peacock, W

    2009-01-01

    The authors' purpose was to determine 30- and 180-day readmission and mortality rates for acutely decompensated heart failure patients receiving nesiritide in the emergency department observation unit. The authors conducted a retrospective evaluation of all patients admitted to the emergency department observation unit, stratified by nesiritide administration, from January 2002 to January 2004. Eligible patients had a primary diagnosis of acutely decompensated heart failure. Observation unit treatment was by previously published protocols, except for nesiritide administration, which was per attending physician choice. Of 595 patients, 196 (33%) received nesiritide. The crude and adjusted odds ratios comparing readmission rates and mortality rates of the nesiritide group with the control group failed to demonstrate significant differences at either the 30- or the 180-day endpoints. The use of nesiritide for acute decompensated heart failure in the emergency department observation unit is not associated with mortality or readmission differences compared with standard therapy alone. PMID:19522957

  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 aspects of human sphincter function

    PubMed Central

    Ustach, Thomas J.; Tobon, Fabio; Hambrecht, Terry; Bass, D. David; Schuster, Marvin M.

    1970-01-01

    In order to investigate the electrophysiology of the human internal anal sphincter and two current concepts of sphincter function, simultaneous manometric and electrical recordings were made from circular smooth muscle of the internal anal sphincter in the resting state and during reflexly induced sphincter relaxation. Three groups were studied: seven normal subjects, 25 patients with functional bowel disease, and seven patients with external sphincter paralysis due to spinal cord lesions. In the resting state slow waves of alternating potential (basic electrical rhythm or BER) were recorded in all subjects. Two types of waves were present, a constant sinusoidal pattern or a spindleshaped pattern. Either pattern was consistent for a given individual. Frequency of BER in the internal sphincter was higher than that recorded in any other gastrointestinal muscle. Our findings indicate that the BER recorded from the internal anal sphincter originates in this muscle. This activity may represent a specialized feature of sphincteric muscle since BER cannot be recorded from isolated nonsphincteric circular muscle. Reproduction of the two patterns of BER by an electronic model suggests that BER, as recorded by this technique, results from a summation of a number of electrically active cells in contact with the recording electrodes. Inhibition of BER occurred when sphincter relaxation was reflexly induced by rectal distension. Both inhibition of BER and degree of sphincter relaxation were proportional to the strength of rectal stimulation, suggesting that strength of stimulus determines the number of active cells which are inhibited. The associations of high frequency of BER with high resting pressure, and of inhibition of BER with sphincter relaxation suggests that maintenance of sphincter tone is an active process that is governed by BER. Images PMID:5409807

  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. PMID:26515317

  12. Electrophysiological studies of texture recognition mechanisms.

    PubMed

    Kharauzov, A K; Shelepin, Yu E; Pronin, S V; Sel'chenkova, T V; Noskov, Ya A

    2008-03-01

    We report here our electrophysiological and psychophysiological studies of the mechanisms by which the visual system recognizes structured images with different levels of ordering. Visual stimuli consisted of textures, i.e., a set of matrixes consisting of Gabor grids. Matrixes differed in terms of the degree of ordering resulting from changes in the probability that grids with the same orientation would appear. The subject's task was to identify the dominant orientation in the stimulus. The relationship between response accuracy, reaction time, and the main characteristics of evoked potentials on the one hand, and the number of identical grids in the matrix on the other was identified. The proportion of correct responses increased and the reaction time decreased as the degree of ordering of stimuli increased. Visual evoked potentials recorded in the occipital areas showed a relationship between the amplitudes of the N2, P2, and P3 waves, with latent periods of 180, 260, and 400 msec, respectively, and matrix parameters. The amplitudes of the P3 component and the positive component recorded in the frontal leads, with a latent period of 250 msec, increased gradually as the task became simpler. The amplitude of the N2 wave also increased with increases in the number of identically oriented elements in the matrix, though this relationship was S-shaped. The magnitude of the P2 component, conversely, was maximal in response to presentation of those matrixes which were most complex to recognize and gradually decreased as the content of identically oriented grids in the matrix increased. These relationships were compared with the statistical characteristics of the stimuli and assessed in terms of the view that the visual system contains two mechanisms, i.e., local and integral image descriptions. PMID:18264768

  13. 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…

  14. 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

  15. 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

  16. 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…

  17. No Evidence for Sex Differences in the Electrophysiological Properties and Excitatory Synaptic Input onto Nucleus Accumbens Shell Medium Spiny Neurons.

    PubMed

    Willett, Jaime A; Will, Tyler; Hauser, Caitlin A; Dorris, David M; Cao, Jinyan; Meitzen, John

    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

  18. Spikes, BOLD, Attention and Awareness: A comparison of electrophysiology and fMRI signals in V1

    PubMed Central

    Boynton, Geoffrey M.

    2014-01-01

    Early fMRI studies comparing results from fMRI and electrophysiology experiments supports the notion that the blood oxygen level dependent (BOLD) signal reliably follows the spiking activity of an underlying neuronal population averaged across a small region in space and a brief period in time. However, more recent studies focusing on higher-level cognitive factors such as attention and visual awareness report striking discrepancies between the fMRI response in humans and electrophysiological signals in macaque early visual areas. Four hypotheses are discussed that can explain the discrepancies between the two methods: (1) the BOLD signal follows local field potential (LFP) signals closer than spikes, and the only the LFP is modulated by top-down factors, (2) the BOLD signal is reflecting electrophysiological signals that are occurring later in time due to feedback delay, (3) the BOLD signal is more sensitive than traditional electrophysiological methods due to massive pooling by the hemodynamic coupling process, and finally (4) there is no real discrepancy, and instead weak but reliable effects on firing rates may be obscured by to differences in experimental design and interpretation of results across methods. PMID:22199162

  19. Dynamic clamp: a powerful tool in cardiac electrophysiology.

    PubMed

    Wilders, Ronald

    2006-10-15

    Dynamic clamp is a collection of closely related techniques that have been employed in cardiac electrophysiology to provide direct answers to numerous research questions regarding basic cellular mechanisms of action potential formation, action potential transfer and action potential synchronization in health and disease. Building on traditional current clamp, dynamic clamp was initially used to create virtual gap junctions between isolated myocytes. More recent applications include the embedding of a real pacemaking myocyte in a simulated network of atrial or ventricular cells and the insertion of virtual ion channels, either simulated in real time or simultaneously recorded from an expression system, into the membrane of an isolated myocyte. These applications have proven that dynamic clamp, which is characterized by the real-time evaluation and injection of simulated membrane current, is a powerful tool in cardiac electrophysiology. Here, each of the three different experimental configurations used in cardiac electrophysiology is reviewed. Also, directions are given for the implementation of dynamic clamp in the cardiac electrophysiology laboratory. With the growing interest in the application of dynamic clamp in cardiac electrophysiology, it is anticipated that dynamic clamp will also prove to be a powerful tool in basic research on biological pacemakers and in identification of specific ion channels as targets for drug development. PMID:16873403

  20. Analysis of alpha particle-driven toroidal Alfv{acute e}n eigenmodes in Tokamak Fusion Test Reactor deuterium{endash}tritium experiments

    SciTech Connect

    Fu, G.Y.; Cheng, C.Z.; Budny, R.; Chang, Z.; Darrow, D.S.; Fredrickson, E.; Mazzucato, E.; Nazikian, R.; Wong, K.L.; Zweben, S.

    1996-11-01

    The toroidal Alfv{acute e}n eigenmodes (TAE) are calculated to be stable in the presently obtained deuterium{endash}tritium plasmas in the Tokamak Fusion Test Reactor (TFTR) [Plasma Phys. Controlled Nucl. Fusion Res. {bold 26}, 11 (1984)]. However, the core localized TAE mode can exist and is less stable than the global TAE modes. The beam ion Landau damping and the radiative damping are the two main stabilizing mechanisms in the present calculation. In future deuterium{endash}tritium experiments, the alpha-driven TAE modes are predicted to occur with a weakly reversed shear profile. {copyright} {ital 1996 American Institute of Physics.}

  1. Acute severe cardiac failure complicating myocardial infarction. Experience with 100 patients referred for consideration of mechanical left ventricular assistance.

    PubMed Central

    O'Rourke, M F; Chang, V P; Windsor, H M; Shanahan, M X; Hickie, J B; Morgan, J J; Gunning, J F; Seldon, A W; Hall, G V; Michell, G; Goldfarb, D; Harrision, D G

    1975-01-01

    One hundred patients were referred with suspected acute cardiac failure following acute myocardial infarction. The diagnosis was confirmed in 72: 31 of these patients underwent elective medical treatment, with 2 survivors (6%); 41 were accepted for counter pulsation, but 9 died before this could be initiated and another 2 died shortly after vain attempts to pass the balloon catheter were abandoned; 30 patients underwent counterpulsation with 14 hospital survivors (47%). Survivor status was usually good. Results of counter pulsation were better in patients who were not shocked (with 5/5 survivors) than in those who were in shock (with 9 of 25 survivors). Results support the view that counterpulsation (alone or combined with corrective surgery) may play an important role in the complications of myocardial infarction provided intervention is early. PMID:1078977

  2. 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

  3. Posaconazole prophylaxis during front-line chemotherapy of acute myeloid leukemia: a single-center, real-life experience

    PubMed Central

    Girmenia, Corrado; Frustaci, Anna Maria; Gentile, Giuseppe; Minotti, Clara; Cartoni, Claudio; Capria, Saveria; Trisolini, Silvia Maria; Matturro, Angela; Loglisci, Giuseppina; Latagliata, Roberto; Breccia, Massimo; Meloni, Giovanna; Alimena, Giuliana; Foà, Robin; Micozzi, Alessandra

    2012-01-01

    Background Posaconazole is effective as primary antifungal prophylaxis of invasive fungal diseases in patients with acute myeloid leukemia. Design and Methods The impact of primary antifungal prophylaxis administered during front-line chemotherapy for acute myeloid leukemia was evaluated by comparing 58 patients who received oral amphotericin B (control group) to 99 patients who received oral posaconazole (posaconazole group). The primary endpoint was the incidence of proven/probable invasive fungal diseases. Secondary endpoints included incidence of invasive aspergillosis, survival at 4 and 12 months after the diagnosis of acute myeloid leukemia and costs. Results Proven/probable invasive fungal diseases were documented in 51.7% of patients in the control group and in 23.2% in the posaconazole group (P=0.0002). Invasive aspergillosis was documented in 43% of patients in the control group and in 15% in the posaconazole group (P=0.002). No survival difference was observed in patients aged over 60 years. In patients aged 60 years or less, a statistically significant survival advantage was observed at 4 months, but no longer at 12 months, in the posaconazole group (P=0.03). It was calculated that in the posaconazole group there was a mean 50% cost reduction for the antifungal drugs. Conclusions Primary antifungal prophylaxis with posaconazole during front-line chemotherapy was effective in preventing invasive fungal diseases in a “real-life” scenario of patients with acute myeloid leukemia, resulted in an early but transitory survival advantage in younger patients and was economically advantageous. PMID:22102706

  4. Spur cell anaemia and acute haemolysis in patients with hyperreactive malarious splenomegaly. Experience in an isolated Yanomamo population of Venezuela.

    PubMed

    Torres R, J R; Magris, M; Villegas, L; Torres V, M A; Dominguez, G

    2000-12-01

    A prospective study, aimed to investigate the aetiology of an unusual clustering of cases of severe acute haemolytic anaemia affecting a high percentage of the adult population, was carried out in two isolated Yanomamo communities of the Upper Orinoco basin in Venezuela. Twenty-six patients with active or recent episodes of severe haemolysis were evaluated. All of them exhibited massive liver and spleen enlargement and fulfilled the diagnostic criteria of the hyperreactive malarious splenomegaly (HMS) syndrome. In four cases with advanced non-alcohol-related chronic liver disease, hypersplenism, severe haemolytic anaemia and acanthocytosis, the characteristic clinical and laboratory findings of spur cell anaemia were documented. Chronic infection by the HBV and HCV was present in three of them. However, in most of the 22 additional HMS cases, the acute haemolytic condition appeared associated with the occurrence of a cold agglutinin-mediated autoimmune response. The clustering of a significant number of cases of severe acute haemolysis in HMS patients from this small isolated aboriginal community is most unusual, and represents a serious complicating factor for a population already beleaguered by a high prevalence of malaria due to multiresistant strains of Plasmodium falciparum. Moreover, the coexistence of HMS and severe chronic HBV or HCV infection may further aggravate the course of the haemolytic disorder, because of the occurrence of spur cell anaemia. PMID:11114387

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

    PubMed

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

    2015-02-01

    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 Ca(2+) 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

  6. 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

  7. 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

  8. 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

  9. Outcome and prognostic factors of malaria-associated acute kidney injury requiring hemodialysis: A single center experience

    PubMed Central

    Kute, V. B.; Shah, P. R.; Munjappa, B. C.; Gumber, M. R.; Patel, H. V.; Jain, S. H.; Engineer, D. P.; Naresh, V. V. Sai; Vanikar, A. V.; Trivedi, H. L.

    2012-01-01

    Acute kidney injury (AKI) is one of the most dreaded complications of severe malaria. We carried out prospective study in 2010, to describe clinical characteristics, laboratory parameters, prognostic factors, and outcome in 59 (44 males, 15 females) smear-positive malaria patients with AKI. The severity of illness was assessed using Acute Physiology and Chronic Health Evaluation (APACHE) II, Sequential Organ Failure Assessment (SOFA) score, Multiple Organ Dysfunction Score (MODS), and Glasgow Coma Scale (GCS) scores. All patients received artesunate and hemodialysis (HD). Mean age of patients was 33.63 ± 14 years. Plasmodium falciparum malaria was seen in 76.3% (n = 45), Plasmodium vivax in 16.9% (n = 10), and mixed infection in 6.8% (n = 4) patients. Presenting clinical features were fever (100%), nausea-vomiting (85%), oliguria (61%), abdominal pain/tenderness (50.8%), and jaundice (74.5%). Mean APACHE II, SOFA, MODS, and GCS scores were 18.1 ± 3, 10.16 ± 3.09, 9.71 ± 2.69, and 14.15 ± 1.67, respectively, all were higher among patients who died than among those who survived. APACHE II ≥20, SOFA and MODS scores ≥12 were associated with higher mortality (P < 0.05). 34% patients received blood component transfusion and exchange transfusion was done in 15%. Mean number of HD sessions required was 4.59 ± 3.03. Renal biopsies were performed in five patients (three with patchy cortical necrosis and two with acute tubular necrosis). 81.3% of patients had complete renal recovery and 11.8% succumbed to malaria. Prompt diagnosis, timely HD, and supportive therapy were associated with improved survival and recovery of kidney functions in malarial with AKI. Mortality was associated with higher APACHE II, SOFA, MODS, GCS scores, requirement of inotrope, and ventilator support. PMID:22279340

  10. Outcome of Acute Kidney Injury in Sudanese Children — An Experience from a Sub-Saharan African Unit

    PubMed Central

    Abdelraheem, Mohamed; Ali, El-Tigani; Osman, Rania; Ellidir, Rashid; Bushara, Amna; Hussein, Rasha; Elgailany, Shiraz; Bakhit, Yassir; Karrar, Mohamed; Watson, Alan; Abu-Aisha, Hasan

    2014-01-01

    ♦ Background: Acute Kidney Injury (AKI) is an important cause of morbidity and mortality in developing countries. Although continuous renal replacement therapy is gaining more popularity worldwide, peritoneal dialysis (PD) in children remains an appropriate therapy for AKI in children for all age groups including neonates. ♦ Methodology: We retrospectively reviewed all children who have been admitted with AKI at the pediatric nephrology unit, Soba University Hospital, Khartoum, during the period from January 2005 to December 2011. ♦ Results: Over 7 years we recorded 659 children of whom 362 (54.9%) were male. The spectrum of age was variable with the majority being neonates, 178 (27.1%). The average patient admission rate was 94 patients per year, with an estimated incidence of 9.8 patients/million population/year. Common causes of AKI were sepsis 202 (30.8%), acute glomerulonephritis 75 (11.5%) and obstructive uropathy due to stones 56 (8.5%). The most common dialysis modality used was PD, 343 (52.4%), and peritonitis was reported in 53 (15.4%) patients. Recovery from AKI was achieved in 450 (68.9%) children, 37 (5.7%) went into chronic kidney disease (CKD), 33 (5.1%) referred to the pediatric surgery and 194 (29.7%) died. ♦ Conclusion: In the setting of developing countries where AKI is a common cause of morbidity and mortality, reasonably equipped renal units with adequately trained medical staff may save many lives. International funding programs for communicable diseases and charity organizations should include AKI management in their programs. Acute PD remains the treatment modality of choice for AKI in developing countries. PMID:24584611

  11. Clinical characteristics and management of patients with early acute severe pancreatitis: Experience from a medical center in China

    PubMed Central

    Tao, Hou-Quan; Zhang, Jing-Xia; Zou, Shou-Chun

    2004-01-01

    AIM: To study clinical characteristics and management of patients with early severe acute pancreatitis (ESAP). METHODS: Data of 297 patients with severe acute pancreatitis (SAP) admitted to our hospital within 72 h after onset of symptoms from January 1991 to June 2003 were reviewed for the occurrence and development of early severe acute pancreatitis (ESAP). ESAP was defined as presence of organ dysfunction within 72 h after onset of symptoms. Sixty-nine patients had ESAP, 228 patients without organ dysfunction within 72 h after onset of symptoms had SAP. The clinical characteristics, incidence of organ dysfunction during hospitalization and prognosis between ESAP and SAP were compared. RESULTS: Impairment degree of pancreas (Balthazar CT class) in ESAP was more serious than that in SAP (5.31 ± 0.68 vs 3.68 ± 0.29, P < 0.01). ESAP had a higher mortality than SAP (43.4% vs 2.6%, P < 0.01), and a higher incidence of hypoxemia (85.5% vs 25%, P < 0.01), pancreas infection (15.9% vs 7.5%, P < 0.05), abdominal compartment syndrome (ACS) (78.3% vs 23.2%, P < 0.01) and multiple organ dysfunction syndrome (MODS)(78.3% vs 10.1%, P < 0.01). In multiple logistic regression analysis, the main predisposing factors to ESAP were higher APACHE II score, Balthazar CT class, MODS and hypoxemia. CONCLUSION: ESAP is characterised by MODS, severe pathological changes of pancreas, early hypoxemia and abdominal compartment syndrome. Given the poor prognosis of ESAP, these patients should be treated in specialized intensive care units with special measures such as close supervision, fluid resuscitation, improvement of hypoxemia, reduction of pancreatic secretion, elimination of inflammatory mediators, prevention and treatment of pancreatic infections. PMID:15040047

  12. An Analysis of Hematological Parameters as a Diagnostic test for Malaria in Patients with Acute Febrile Illness: An Institutional Experience

    PubMed Central

    Jairajpuri, Zeeba Shamim; Rana, Safia; Hassan, Mohd Jaseem; Nabi, Farhat; Jetley, Sujata

    2014-01-01

    Objectives Hematological changes are among the most common complications encountered in malaria. This study analyzes and statistically evaluates the hematological changes as a diagnostic test for malaria in patients with acute febrile illness and whether these could guide the physician to institute specific antimalarial treatment. Methods The present study was an observational study, conducted from January to December 2012. A total of 723 patients presenting with acute febrile illness at our hospital were evaluated. A complete blood count and malarial parasite microscopy were performed for each patient. Results The findings showed that 172 out of 723 patients (24%) were diagnosed to have malaria by positive smear report. There were 121 males and 51 females with a male to female ratio of 2.3:1. Maximum number of cases were seen in the 20-30 years age group. There was a statistically significant reduction in hemoglobin (p<0.005), platelet count (p<0.001) and total leukocyte count (p<0.001) levels in patients with malaria compared to those without the disease. Likelihood ratios for a positive result of platelets (6.2) and total leukocyte count (3.4) was relevant as compared to hemoglobin (1.61) and Red cell distribution width (1.79). The negative predictive values for hemoglobin (79%), total leukocyte count (86%), platelets (94%) and Red cell distribution width (93%) were significant. Red cell distribution width values were found to be higher in patients with malaria than in patients without malaria (p<0.001). Conclusion This study revealed that routinely used laboratory findings such as hemoglobin, leukocytes, platelet counts and even red cell distribution width values can provide a diagnostic clue in a patient with acute febrile illness in endemic areas, thus increasing the probability of malaria and enhancing prompt initiation of treatment. PMID:24498476

  13. Electrophysiology in the eukaryotic model cell Saccharomyces cerevisiae.

    PubMed

    Bertl, A; Bihler, H; Kettner, C; Slayman, C L

    1998-11-01

    Since the mid-1980s, use of the budding yeast, Saccharomyces cerevisiae, for expression of heterologous (foreign) genes and proteins has burgeoned for several major purposes, including facile genetic manipulation, large-scale production of specific proteins, and preliminary functional analysis. Expression of heterologous membrane proteins in yeast has not kept pace with expression of cytoplasmic proteins for two principal reasons: (1) although plant and fungal proteins express and function easily in yeast membranes, animal proteins do not, at least yet; and (2) the yeast plasma membrane is generally regarded as a difficult system to which to apply the standard electrophysiological techniques for detailed functional analysis of membrane proteins. Especially now, since completion of the genome-sequencing project for Saccharomyces, yeast membranes themselves can be seen as an ample source of diverse membrane proteins - including ion channels, pumps, and cotransporters - which lend themselves to electrophysiological analysis, and specifically to patch-clamping. Using some of these native proteins for assay, we report systematic methods to prepare both the yeast plasma membrane and the yeast vacuolar membrane (tonoplast) for patch-clamp experiments. We also describe optimized ambient conditions - such as electrode preparation, buffer solutions, and time regimens - which facilitate efficient patch recording from Saccharomyces membranes. There are two main keys to successful patch-clamping with Saccharomyces. The first is patience; the second is scrupulous cleanliness. Large cells, such as provided by polyploid strains, are also useful in yeast patch recording, especially while the skill required for gigaseal formation is being learned. Cleanliness is aided by (1) osmotic extrusion of protoplasts, after minimal digestion of yeast walls; (2) use of a rather spare suspension of protoplasts in the recording chamber; (3) maintenance of continuous chamber perfusion prior to

  14. 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. PMID:26696708

  15. Alterations of the electrophysiological properties from cortical layer 5 pyramidal neurons in temporary rapamycin-treated rodent brain slices.

    PubMed

    Ren, Keming; Chen, Lijuan; Sheng, Guoxia; Wang, Jiangping; Jin, Xiaoming; Jiang, Kewen

    2016-01-26

    The mammalian target of rapamycin (mTOR) signaling pathway is involved in neuro-developmental/degenerative and neuropsychiatric abnormalities. Rapamycin, a specific and potent inhibitor of mTOR signaling, could regulate synaptic plasticity and synaptic transmission of glutamatergic neurons following prolonged treatment. Its immediate effects on electrophysiological properties of cortical layer 5 (L5) pyramidal neurons where the information undergoes a sophisticated processing remain unknown. Here, we found that acute (within 2min) bath-application of rapamycin (0.5μgml(-1)) was able to depolarize the current-clamp baseline potentials significantly at postnatal day (P) 4, P10 in rats and P90 in mice (P<0.05), and altered the membrane current/voltage (I/V) curves in an age-dependent manner. Rapamycin not only increased the standard deviation or the peak amplitude of baseline membrane potential, but also increased the frequencies of spontaneous action potentials in more mature neurons (P10 and P90). In addition, rapamycin decreased the burst-firing frequencies of cortical L5 burst-spiking neurons from mature brains, and further switched their firing modes to regular-spiking ones. These findings suggest that acute inhibition of mTOR signaling by rapamycin induces an immediate impact on L5 pyramidal neurons' electrophysiological properties, indicating that its effects might involve mechanisms of ion channel's regulation. PMID:26639426

  16. Experience in the use of Actovegin in the treatment of patients with cognitive disorders in the acute period of stroke.

    PubMed

    Derev'yannykh, E A; Bel'skaya, G N; Knoll, E A; Krylova, L G; Popov, D V

    2008-10-01

    Forty-three patients with mild-moderate ischemic stroke were studied in the acute period and were divided into two groups. The experimental group consisted of 32 patients who were given Actovegin; the reference group consisted of 11 patients who were given piracetam. Patients were investigated before treatment and at 10 and 30 days; investigations included examination, points assessments of neurological disorders using the original Gusev-Skvortsova scale, neuropsychological tests using the MMSE scale, rheoencephalography, and electroencephalography. Analysis of changes in clinical features in patients treated with Actovegin during the acute period showed that Actovegin had clear positive effects both on general cerebral and on focal neurological symptoms. By the end of treatment, the extent of recovery of impaired functions, assessed in terms of total ischemic points and cognitive functions, was significantly greater in patients treated with Actovegin than in patients given piracetam. These data lead to the conclusion that Actovegin is effective in the treatment of patients with ischemic stroke. PMID:18802768

  17. Inflammation of the external ear in acute chikungunya infection: Experience from the outbreak in Johor Bahru, Malaysia, 2008.

    PubMed

    Javelle, Emilie; Tiong, Tee Hua; Leparc-Goffart, Isabelle; Savini, Hélène; Simon, Fabrice

    2014-04-01

    The re-emerging invalidating chikungunya disease has recently extended to temperate areas. Other alphaviruses can also present with febrile arthalgias. Dengue virus transmitted by the same species of mosquitoes may cocirculate, leading to dual infections and concurrent epidemics. Although these diseases share similar clinical features, their prognoses considerably differ. Prominent and prolonged articular disorders are more consistent with chikungunya virus, whereas haemorrhages make the gravity of dengue infection. Specific symptoms are required, especially when diagnostic tests are not available or performable at a large scale. Indeed, early clinical suspicion of a vector-borne disease is crucial to isolate the first cases in the course of an outbreak, and discrimination between arboviruses help to optimal management of patients. No specific chikungunya clinical sign has been yet reported. We highlight here the high prevalence (about 25%) of acute ear redness in infected people during the 2008 chikungunya outbreak in Jahor Bahru in Malaysia. Nine consenting patients are more precisely described. Ear chondritis could be sensitive diagnostic criterion of the acute stage of chikungunya, every physician - even in occidental non endemic areas - should be aware of. PMID:24556566

  18. Is it possible to limit the use of CT scanning in acute diverticular disease without compromising outcomes? A preliminary experience.

    PubMed

    Caputo, Pierpaolo; Rovagnati, Marco; Carzaniga, Pier Luigi

    2015-01-01

    The aim of our study was to determine whether the use of CT scanning in the assessment of acute diverticulitis can be reduced without a negative effect on outcome. Our series consisted of 93 out of 100 patients with acute diverticulitis admitted to the Emergency Room of our institution in the period from February 2012 to March 2013.The Hinchey classification system was used to stage disease based on findings on ultrasound (US) examination and/or computed tomography (CT) scanning. We compared the patients' Hinchey stage (HS) on admission and 72 hours later. Types of treatment were defined as emergency or delayed intervention (operative approaches (OA); ultrasound-guided percutaneous drainage (UPD), and surgery. The borderline between conservative and surgical management was identified. In patients with a HS

  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. PMID:24268501

  20. 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…

  1. Function and modulation of bacterial porins: insights from electrophysiology.

    PubMed

    Delcour, A H

    1997-06-15

    Electrophysiological techniques provide a wealth of information regarding the molecular mechanisms that underlie the function and modulation of ion channels. They have revealed that bacterial porins do not behave as static, permanently open pores but display a much more complex and dynamic behavior than anticipated from non-electrophysiological studies. The channels switch between short-lived open and closed conformations (gating activity), and can also remain in an inactivated, non-ion conducting state for prolonged periods of time. Thus the role of porins is not limited to that of a molecular filter, but is extended to the control of outer membrane permeability through the regulation of their activity. Electrophysiological studies have indeed demonstrated that both gating and inactivation are modulated by a variety of physical and chemical parameters and are highly cooperative phenomena, often involving numerous channels working in concert. Cooperativity acts as an amplification mechanism that grants a large population of porins, such as found in the outer membrane, with sensitivity to modulation by external or internal factors. By conferring permeability properties to the outer membrane, porins play a crucial role in the bacterium's antibiotic susceptibility and survival in various environmental conditions. The detailed information that electrophysiology only can provide on porin function and modulation promises to yield a more accurate description of how porin properties can be used by cells to adapt to a changing environment, and to offer mechanisms that might optimize the drug sensitivity of the microorganism. PMID:9228742

  2. 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…

  3. Electrophysiological Monitoring of Brain Injury and Recovery after Cardiac Arrest

    PubMed Central

    Deng, Ruoxian; Xiong, Wei; Jia, Xiaofeng

    2015-01-01

    Reliable prognostic methods for cerebral functional outcome of post cardiac-arrest (CA) patients are necessary, especially since therapeutic hypothermia (TH) as a standard treatment. Traditional neurophysiological prognostic indicators, such as clinical examination and chemical biomarkers, may result in indecisive outcome predictions and do not directly reflect neuronal activity, though they have remained the mainstay of clinical prognosis. The most recent advances in electrophysiological methods—electroencephalography (EEG) pattern, evoked potential (EP) and cellular electrophysiological measurement—were developed to complement these deficiencies, and will be examined in this review article. EEG pattern (reactivity and continuity) provides real-time and accurate information for early-stage (particularly in the first 24 h) hypoxic-ischemic (HI) brain injury patients with high sensitivity. However, the signal is easily affected by external stimuli, thus the measurements of EP should be combined with EEG background to validate the predicted neurologic functional result. Cellular electrophysiology, such as multi-unit activity (MUA) and local field potentials (LFP), has strong potential for improving prognostication and therapy by offering additional neurophysiologic information to understand the underlying mechanisms of therapeutic methods. Electrophysiology provides reliable and precise prognostication on both global and cellular levels secondary to cerebral injury in cardiac arrest patients treated with TH. PMID:26528970

  4. Arrhythmogenesis Research: A Perspective from Computational Electrophysiology Viewpoint

    PubMed Central

    Trayanova, Natalia; Plank, Gernot

    2012-01-01

    The mechanisms by which arrhythmias are generated in the heart remains a field of intensive research. Recent advances in computational biology and electrophysiology have enabled researchers to use an alternative tool in the study of arrhythmia mechanisms, the multi-scale modeling and simulation of cardiac arrhythmogenesis at the organ level. This article reviews the recent advances and achievements using this approach. PMID:18001976

  5. A heated stage and tissue culture chamber for electrophysiology.

    PubMed

    Bonkowski, L; Runion, H I

    1976-12-15

    A simple, inexpensive heating circuit is described for use with a warmed microscope stage, small tissue bath, and heated tissue culture chamber. A major consideration in the design of the apparatus is a compatability with electrophysiological studies. Thus, proper shielding and low profile for microelectrode positioning are featured. PMID:1021472

  6. Combining single-molecule imaging and single-channel electrophysiology.

    PubMed

    Weatherill, Eve E; Wallace, Mark I

    2015-01-16

    Combining simultaneous single-molecule fluorescence measurements of ion channel conformational change with single-channel electrophysiology would enable a direct link between structure and function. Such methods would help us to create a truly molecular "movie" of how these important biomolecules work. Here we review past and recent progress toward this goal. PMID:25026065

  7. Acute Bronchitis

    MedlinePlus

    ... or though physical contact (for example, on unwashed hands). Being exposed to tobacco smoke, air pollution, dusts, vapors, and fumes can also cause acute bronchitis. Less often, bacteria can also cause acute bronchitis. To diagnose acute ...

  8. Cystitis - acute

    MedlinePlus

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

  9. 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

  10. The application of elastomeric connector for multi-channel electrophysiological recordings.

    PubMed

    Szabó, Imre; Máthé, Kálmán; Tóth, Attila; Hernádi, István; Czurkó, András

    2002-02-15

    Interest in recording multi-channel electrophysiological data from behaving animals is rapidly growing, and many laboratories tend to record a large number of EEG and/or multi-unit channels, despite the limitation of the size of the headpiece that a small behaving animal can carry. A common drawback of these experiments, therefore, is the relatively large size of even the smallest, commercially available, high-density micro-connectors for the headset. To overcome this problem, we suggest the application of elastomeric or silicone inter-rubber connectors, that are widely used in electronics. The elastomeric or "zebra" connector consists of alternating thin strips of layered electrically conductive and non-conductive materials. The conductive strips provide electrical connections between uninsulated contact surfaces of printed circuit boards such as the connector plate of the micro-drive, that holds the brain electrode wires, and the preamplifier board of the recording system. In the present paper, we provide technical details of the design of this type of connector-sets and discuss common issues arising from their use. By comparing the applicability of two designs, we aim to demonstrate the simplicity, reliability and durability of the elastomeric inter-rubber connectors in electrophysiological experiments on freely moving laboratory animals. PMID:11850041

  11. 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. PMID:8788064

  12. 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. PMID:27503901

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

    PubMed Central

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

    2015-01-01

    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

  14. Virtual Electrophysiological Study of Atrial Fibrillation in Fibrotic Remodeling

    PubMed Central

    McDowell, Kathleen S.; Zahid, Sohail; Vadakkumpadan, Fijoy; Blauer, Joshua; MacLeod, Rob S.; Trayanova, Natalia A.

    2015-01-01

    Research has indicated that atrial fibrillation (AF) ablation failure is related to the presence of atrial fibrosis. However it remains unclear whether this information can be successfully used in predicting the optimal ablation targets for AF termination. We aimed to provide a proof-of-concept that patient-specific virtual electrophysiological study that combines i) atrial structure and fibrosis distribution from clinical MRI and ii) modeling of atrial electrophysiology, could be used to predict: (1) how fibrosis distribution determines the locations from which paced beats degrade into AF; (2) the dynamic behavior of persistent AF rotors; and (3) the optimal ablation targets in each patient. Four MRI-based patient-specific models of fibrotic left atria were generated, ranging in fibrosis amount. Virtual electrophysiological studies were performed in these models, and where AF was inducible, the dynamics of AF were used to determine the ablation locations that render AF non-inducible. In 2 of the 4 models patient-specific models AF was induced; in these models the distance between a given pacing location and the closest fibrotic region determined whether AF was inducible from that particular location, with only the mid-range distances resulting in arrhythmia. Phase singularities of persistent rotors were found to move within restricted regions of tissue, which were independent of the pacing location from which AF was induced. Electrophysiological sensitivity analysis demonstrated that these regions changed little with variations in electrophysiological parameters. Patient-specific distribution of fibrosis was thus found to be a critical component of AF initiation and maintenance. When the restricted regions encompassing the meander of the persistent phase singularities were modeled as ablation lesions, AF could no longer be induced. The study demonstrates that a patient-specific modeling approach to identify non-invasively AF ablation targets prior to the clinical

  15. Electrophysiological and behavioural characterization of gustatory responses to antennal 'bitter' taste in honeybees.

    PubMed

    de Brito Sanchez, Maria Gabriela; Giurfa, Martin; de Paula Mota, Theo Rolla; Gauthier, Monique

    2005-12-01

    We combined behavioural and electrophysiological experiments to study whether bitter taste is perceived at the antennal level in honeybees, Apis mellifera. Our behavioural studies showed that neither quinine nor salicin delivered at one antenna at different concentrations induced a retraction of the proboscis once it was extended in response to 1 M sucrose solution delivered to the opposite antenna. Bees that extended massively their proboscis to 1 M sucrose responded only partially when stimulated with a mixture of 1 M sucrose and 100 mM quinine. The mixture of 1 m sucrose and 100 mM salicin had no such suppressive effect. No behavioural suppression was found for mixtures of salt solution and either bitter substance. Electrophysiological recordings of taste sensillae at the antennal tip revealed sensillae that responded specifically either to sucrose or salt solutions, but none responded to the bitter substances quinine and salicin at the different concentrations tested. The electrophysiological responses of sensillae to 15 mM sucrose solution were inhibited by a mixture of 15 mM sucrose and 0.1 mM quinine, but not by a mixture of 15 mM sucrose and 0.1 mM salicin. The responses of sensillae to 50 mM NaCl were reduced by a mixture of 50 mm NaCl and 1 mM quinine but not by a mixture of 50 mM NaCl and 1 mM salicin. We concluded that no receptor cells for the bitter substances tested, exist at the level of the antennal tip of the honeybee and that antennal bitter taste is not represented as a separate perceptual quality. PMID:16367782

  16. Electrophysiological properties of mouse dopamine neurons: in vivo and in vitro studies.

    PubMed

    Sanghera, M K; Trulson, M E; German, D C

    1984-07-01

    The present experiments were conducted to determine the electrophysiological and pharmacological properties of substantia nigra neurons in the mouse. These cells were studied using extracellular single unit recording and microiontophoretic techniques in both chloral hydrate anesthetized mice and in vitro mouse slices. In the in vivo preparation the substantia nigra zona compacta neurons had long duration action potentials (greater than 4 ms), fired from 1 to 7 impulses/s, and the cells discharged with either a decremental burst pattern or with a regular pattern. The dopamine agonists apomorphine and d-amphetamine, given systemically, decreased the firing rate of these neurons and the dopamine receptor blocker, haloperidol, reversed these effects. The zona compacta neurons were inhibited by the micro-iontophoretic application of dopamine and gamma-aminobutyric acid, and systemic haloperidol selectively attenuated the effects of dopamine. In vitro recordings from substantia nigra zona compacta and zona reticulata neurons were generally similar to those found in vivo, both in terms of the electrophysiological and pharmacological properties. However, the zona compacta cells fired faster in vitro than in vivo, and the firing pattern in vitro tended to be pacemaker-like, especially when recordings were made in an incubation medium which blocks synaptic transmission (e.g. low Ca2+/high Mg2+). Our data indicate that: (a) in vivo mouse zona compacta neurons exhibit the same electrophysiological and pharmacological properties as rat dopamine-containing neurons; (b) in vitro mouse dopaminergic neurons fire with pacemaker regularity when in a low Ca2+/high Mg2+ environment; and (c) in vitro studies offer an approach to examine the basic properties of dopaminergic neurons exclusive of feedback pathways and other afferent inputs. PMID:6472621

  17. 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

  18. Subtype Identification in Acutely Dissociated Rat Nodose Ganglion Neurons Based on Morphologic Parameters

    PubMed Central

    Lu, Xiao-Long; Xu, Wen-Xiao; Yan, Zhen-Yu; Qian, Zhao; Xu, Bing; Liu, Yang; Han, Li-Min; Gao, Rui-Chen; Li, Jun-Nan; Yuan, Mei; Zhao, Chong-Bao; Qiao, Guo-fen; Li, Bai-Yan

    2013-01-01

    Nodose ganglia are composed of A-, Ah- and C-type neurons. Despite their important roles in regulating visceral afferent function, including cardiovascular, pulmonary, and gastrointestinal homeostasis, information about subtype-specific expression, molecular identity, and function of individual ion transporting proteins is scarce. Although experiments utilizing the sliced ganglion preparation have provided valuable insights into the electrophysiological properties of nodose ganglion neuron subtypes, detailed characterization of their electrical phenotypes will require measurements in isolated cells. One major unresolved problem, however, is the difficulty to unambiguously identify the subtype of isolated nodose ganglion neurons without current-clamp recording, because the magnitude of conduction velocity in the corresponding afferent fiber, a reliable marker to discriminate subtypes in situ, can no longer be determined. Here, we present data supporting the notion that application of an algorithm regarding to microscopic structural characteristics, such as neuron shape evaluated by the ratio between shortest and longest axis, neuron surface characteristics, like membrane roughness, and axon attachment, enables specific and sensitive subtype identification of acutely dissociated rat nodose ganglion neurons, by which the accuracy of identification is further validated by electrophysiological markers and overall positive predictive rates is 89.26% (90.04%, 76.47%, and 98.21% for A-, Ah, and C-type, respectively). This approach should aid in gaining insight into the molecular correlates underlying phenotypic heterogeneity of nodose ganglia. Additionally, several critical points that help for neuron identification and afferent conduction calibration are also discussed. PMID:23904796

  19. An analysis of clinical process measures for acute healthcare delivery in Appalachia: The Roane Medical Center experience

    PubMed Central

    Pope, Karla Rae; Hancock, John S; Sills, Eric Scott

    2006-01-01

    Objective To survey management of selected emergency healthcare needs in a Tennessee community hospital. Materials and methods In this descriptive report, discharges and associated standard process measures were retrospectively studied for Roane Medical Center (RMC) in Harriman, Tennessee (pop. 6,757). Hospital data were extracted from a nationwide database of short-term acute care hospitals to measure 16 quality performance measures in myocardial infarction (MI), heart failure, and pneumonia during the 14 month interval ending March 2005. The data also permitted comparisons with state and national reference groups. Results Of RMC patients with myocardial infarction (MI), 94% received aspirin on arrival, a figure higher than both state (85%) and national (91%) averages. Assessment of left ventricular dysfunction among heart failure patients was also higher at RMC (98%) than the state (74%) or national (79%) average. For RMC pneumonia patients, 79% received antibiotics within 4 h of admission, which compared favorably with State (76%) and national (75%) average. RMC scored higher on 13 of 16 clinical process measures (p<0.01, sign test analysis, >95% CI) compared to state and national averages. Discussion Although acute health care needs are often met with limited resources in medically underserved regions, RMC performed above state and national average for most process measures assessed in this review. Our data were derived from one facility and the associated findings may not be applicable in other healthcare settings. Further studies are planned to track other parameters and specific clinical outcomes at RMC, as well as to identify specific institutional policies that facilitate attainment of target quality measures. PMID:16571127

  20. The mixed blessing of treating symptoms in acute vestibular failure--evidence from a 4-aminopyridine experiment.

    PubMed

    Beck, Roswitha; Günther, Lisa; Xiong, Guoming; Potschka, Heidrun; Böning, Guido; Bartenstein, Peter; Brandt, Thomas; Jahn, Klaus; Dieterich, Marianne; Strupp, Michael; la Fougère, Christian; Zwergal, Andreas

    2014-11-01

    Early symptomatic treatment of acute unilateral vestibulopathy is thought to impede the course of ensuing central vestibular compensation (VC). Despite the great clinical importance of this hypothesis there is no experimental evidence of its validity. The present study addressed this question by investigating the direct effect of 4-aminopyridine (4-AP) on ocular motor and postural symptoms in acute unilateral vestibulopathy as well as its long-term consequences for VC in a rat model of chemical unilateral labyrinthectomy (UL). After UL, one group of Sprague-Dawley rats was treated with 4-AP p.o. (1mg/kg/day), another with 0.9% NaCl solution p.o. for 3days. Behavioural testing for symptoms of vestibular tone imbalance was done 1day before and 1, 2, 3, 5, 7, 9, 15, 21, and 30days after UL. In addition, sequential whole-brain [(18)F]-FDG-μPET was performed before and 1, 3, 7, 15, and 30days after UL to examine and visualize 4-AP-induced modulation of VC. Administration of 4-AP on days 1-3 significantly improved postural imbalance 2h after administration compared to that in controls. This effect was only transient. Remarkably, the 4-AP group had a prolonged and impaired course of postural compensation compared to that of controls. The μPET revealed a significant increase of regional cerebral glucose metabolism (rCGM) in the vestibulocerebellum 2h after administration of 4-AP. However, the 4-AP group exhibited a persistent asymmetry of rCGM after day 3 in the vestibular nuclei and posterolateral thalami. In conclusion, this study confirms the hypothesis that early pharmacological abatement of vestibular symptoms impedes VC. PMID:25157903

  1. [Treatment of acute promyelocytic leukemia with trans-retinoic acid. Experience of the Santa Maria Hospital, Medical School of Lisbon].

    PubMed

    De Lacerda, J F; Do Carmo, J A; De Moura, M C; Guerra, M L; Lopes, C; Raposo, J; Melo, A; De Oliveira, J J; De Lacerda, J M

    1994-12-01

    Acute promyelocytic leukemia (APL) is a rare subtype of acute myelogenous leukemia that is usually associated with a fatal hemorrhagic diathesis. All trans-retinoic acid (ATRA) is an active metabolite of vitamin A that differentiates the malignant cell clone, corrects the coagulopathy, and induces complete remission in the vast majority of patients with APL. Between June 1992 and September 1993, 8 patients with APL (4 previously untreated, 3 in first relapse and 1 in second relapse) received ATRA. Complete remission was achieved in 7 patients; in 5 with ATRA alone and in 2 with ATRA followed by cytotoxic chemotherapy due to the development of asymptomatic hyperleukocytosis. The earliest signs of response were the correction of the coagulopathy and an increase in the white blood cell count. Sequential morphological and immunophenotypical analyses of the bone marrow revealed differentiation of the malignant cell clone, in the absence of bone marrow hypoplasia. 4 of 5 patients treated only with ATRA until complete remission had late leukopenia. The most frequent adverse effects were dryness of skin and mucosae, hypertrigliceridemia and hypercholesterolemia, and a moderate increase in liver transaminases. An increase in the white blood cell count was common, and in two cases exceeded 35.0 x 10(9)/l. One of these patients developed multiple thrombosis of the extremities after cytotoxic chemotherapy. We frequently observed an increase in lactic dehydrogenase levels that was concomitant with the peak in the white blood cell count. The only patient on whom complete remission was not achieved was 60 years old, had chronic obstructive pulmonary disease, and died in the third week of therapy with a pulmonary distress syndrome.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7717119

  2. Acute kidney injury due to anti-tuberculosis drugs: a five-year experience in an aging population

    PubMed Central

    2014-01-01

    Background Patients on anti-tuberculosis treatment may develop acute kidney injury (AKI), but little is known about the renal outcome and prognostic factors, especially in an aging population. This study aimed to calculate the incidence of AKI due to anti-TB drugs and analyze the outcomes and predictors of renal recovery. Methods From 2006 to 2010, patients on anti-TB treatment were identified and their medical records reviewed. Acute kidney injury was defined according to the criteria established by the AKI Network, while renal recovery was defined as a return of serum creatinine to baseline. Predictors of renal recovery were identified by Cox regression analysis. Results Ninety-nine out of 1394 (7.1%) patients on anti-TB treatment had AKI. Their median age was 68 years and there was male predominance. Sixty (61%) developed AKI within two months of anti-TB treatment, including 11 (11%) with a prior history of rifampin exposure. Thirty (30%) had co-morbid chronic kidney disease or end-stage renal disease. The median time of renal recovery was 39.6 days (range, 1–180 days). Factors predicting renal recovery were the presence of fever, rash, and gastro-intestinal disturbance at the onset of AKI. Sixty-two of the 71 (87%) patients who recovered from AKI had successful re-introduction or continuation of rifampin. Conclusions Renal function impairment is not a rare complication during anti-TB treatment in an elderly population. The presence of fever and rash may be associated with renal recovery. Rifampin can still be used in most patients who recover from AKI. PMID:24410958

  3. 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.

  4. Adjudication of etiology of acute kidney injury: experience from the TRIBE-AKI multi-center study

    PubMed Central

    2014-01-01

    Background Adjudication of patient outcomes is a common practice in medical research and clinical trials. However minimal data exists on the adjudication process in the setting of Acute Kidney Injury (AKI) as well as the ability to judge different etiologies (e.g. Acute Tubular Necrosis (ATN), Pre-renal Azotemia (PRA)). Methods We enrolled 475 consecutive patients undergoing cardiac surgery at four sites of the Translational Research Investigating Biomarker Endpoints in AKI (TRIBE-AKI) study. Three expert nephrologists performed independent chart review, utilizing clinical variables and retrospective case report forms with pre intra and post-operative data, and then adjudicated all cases of AKI (n = 67). AKI was defined as a > 50% increase in serum creatinine for baseline (RIFLE Risk). We examined the patterns of AKI diagnoses made by the adjudication panel as well as association of these diagnoses with pre and postoperative kidney injury biomarkers. Results There was poor agreement across the panel of reviewers with their adjudicated diagnoses being independent of each other (Fleiss’ Kappa = 0.046). Based on the agreement of the two out of three reviewers, ATN was the adjudicated diagnosis in 41 cases (61%) while PRA occurred in 13 (19%). Neither serum creatinine or any other biomarker of AKI (urine or serum), was associated with an adjudicated diagnosis of ATN within the first 24 post-operative hours. Conclusion The etiology of AKI after cardiac surgery is probably multi-factorial and pure forms of AKI etiologies, such as ATN and PRA may not exist. Biomarkers did not appear to correlate with the adjudicated etiology of AKI; however the lack of agreement among the adjudicators impacted these results. Trial registration Clinicaltrials.gov: NCT00774137 PMID:24996668

  5. Aetiology and Outcome of Acute Liver Failure in Children: Experience at a Tertiary Care Hospital of Bangladesh.

    PubMed

    Mazumder, M W; Karim, A B; Rukunuzzaman, M; Rahman, M A

    2016-07-01

    Acute liver failure (ALF) is a rapidly progressive, potentially fatal syndrome resulting from rapid death or injury to a large proportion of hepatocytes, caused by a variety of insult, leaving insufficient hepatic paranchymal mass to sustain liver function. The aetiology of ALF varies according to the age of patient and development of the country. The outcome of ALF also varies according to aetiology: survival is better in paracetamol poisoning whereas it is poor in metabolic diseases. The present study was undertaken to observe the underlying aetiology and outcome of ALF in children under 18 years of age admitted at the department of Paediatric Gastroenterology & Nutrition, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. It was a retrospective review of medical records from November 2011 through October 2014. During this period a total of 35 patients were diagnosed to have ALF. Aetiology was established in 25(71.4%) cases, whereas in 10(28.6%) cases, no identifiable cause was found. Viral hepatitis was the underlying cause in 12(34.3%) cases. After treatment 15(43%) ALF patients survived, 8(23%) left hospital with risk bond (DORB), and 12(34%) patients died. The study showed that among the 12 death patients, 5(41.7%) had viral hepatitis, 3(25%) Wilson's disease, and in 4(33.3%) no cause could be identified. Viral hepatitis and Wilson disease were found to be two common causes of ALF in this study. Future studies with larger sample size are required to know the actual causes of acute liver failure in Bangladeshi children. PMID:27612896

  6. 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

  7. 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

  8. Latrunculin B modulates electrophysiological characteristics and arrhythmogenesis in pulmonary vein cardiomyocytes.

    PubMed

    Lu, Yen-Yu; Lin, Yung-Kuo; Wen, Zhi-Hong; Chen, Yao-Chang; Chen, Shih-Ann; Chen, Yi-Jen

    2016-05-01

    AF (atrial fibrillation) is the most common sustained arrhythmia, and the PVs (pulmonary veins) play a critical role in triggering AF. Stretch causes structural remodelling, including cytoskeleton rearrangement, which may play a role in the genesis of AF. Lat-B (latrunculin B), an inhibitor of actin polymerization, is involved in Ca(2+) regulation. However, it is unclear whether Lat-B directly modulates the electrophysiological characteristics and Ca(2+) homoeostasis of the PVs. Conventional microelectrodes, whole-cell patch-clamp, and the fluo-3 fluorimetric ratio technique were used to record ionic currents and intracellular Ca(2+) within isolated rabbit PV preparations, or within isolated single PV cardiomyocytes, before and after administration of Lat-B (100 nM). Langendorff-perfused rabbit hearts were exposed to acute and continuous atrial stretch, and we studied PV electrical activity. Lat-B (100 nM) decreased the spontaneous electrical activity by 16±4% in PV preparations. Lat-B (100 nM) decreased the late Na(+) current, L-type Ca(2+) current, Na(+)/Ca(2+) exchanger current, and stretch-activated BKCa current, but did not affect the Na(+) current in PV cardiomyocytes. Lat-B reduced the transient outward K(+) current and ultra-rapid delayed rectifier K(+) current, but increased the delayed rectifier K(+) current in isolated PV cardiomyocytes. In addition, Lat-B (100 nM) decreased intracellular Ca(2+) transient and sarcoplasmic reticulum Ca(2+) content in PV cardiomyocytes. Moreover, Lat-B attenuated stretch-induced increased spontaneous electrical activity and trigger activity. The effects of Lat-B on the PV spontaneous electrical activity were attenuated in the presence of Y-27632 [10 μM, a ROCK (Rho-associated kinase) inhibitor] and cytochalasin D (10 μM, an actin polymerization inhibitor). In conclusion, Lat-B regulates PV electrophysiological characteristics and attenuates stretch-induced arrhythmogenesis. PMID:26839418

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

    PubMed

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

    2016-08-01

    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

  10. Outcomes in Stable Patients With Previous Atherothrombotic Events Receiving Vorapaxar Who Experience a New Acute Coronary Event (from TRA2°P-TIMI 50).

    PubMed

    Berg, David D; Bonaca, Marc P; Braunwald, Eugene; Corbalan, Ramon; Goto, Shinya; Kiss, Robert G; Murphy, Sabina A; Scirica, Benjamin M; Spinar, Jindrich; Morrow, David A

    2016-04-01

    Vorapaxar is a first-in-class protease-activated receptor-1 antagonist indicated for secondary prevention in stable patients with previous myocardial infarction (MI) or peripheral artery disease and no cerebrovascular disease. Vorapaxar is not recommended for initiation in the acute phase of acute coronary syndromes (ACS) because of an unfavorable balance between bleeding and efficacy when started in that setting. The aim of this analysis was to investigate outcomes in patients who experienced a new ACS while receiving vorapaxar for long-term secondary prevention. Thrombin Receptor Antagonist in Secondary Prevention of Atherothrombotic ischemic Events-Thrombolysis In Myocardial Infarction 50 was a randomized, double-blind, placebo-controlled trial of vorapaxar (n = 26,449). We evaluated bleeding and ischemic events during the acute care of patients with a new ACS during the trial. During a median follow-up of 30 months, 799 patients (8.9%) randomized to vorapaxar and 913 (10.0%) to placebo had a new ACS event (p = 0.003); 87% and 86%, respectively, were on study therapy at the time of the event. In a landmark analysis through 7 days after ACS, the rates of Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) severe bleeding were 0.8% versus 0.8% (hazard ratio [HR] 0.99, 95% CI 0.33 to 2.94) and GUSTO moderate/severe bleeding were 2.5% versus 1.6% (HR 1.59, 95% CI 0.78 to 3.24) with vorapaxar versus placebo. The effect of vorapaxar on cardiovascular death, MI, or stroke (2.4% vs 4.4%; HR 0.54, 95% CI 0.31 to 0.93; p = 0.027) was consistent with the overall trial result. In conclusion, in patients who experience a new ACS event while receiving vorapaxar for secondary prevention, continuing therapy was associated with favorable efficacy without excess severe bleeding during the period of acute ACS management. PMID:26876014

  11. 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.,…

  12. 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…

  13. Informed consent for clinical trials in acute coronary syndromes and stroke following the European Clinical Trials Directive: investigators' experiences and attitudes

    PubMed Central

    Iwanowski, Piotr; Budaj, Andrzej; Członkowska, Anna; Wąsek, Wojciech; Kozłowska-Boszko, Beata; Olędzka, Urszula; Masełbas, Wojciech

    2008-01-01

    Background During clinical trials in emergency medicine, providing appropriate oral and written information to a patient is usually a challenge. There is little published information regarding patients' opinions and competence to provide informed consent, nor on physicians' attitudes towards the process. We have investigated the problem of obtaining consent from patients in emergency-setting clinical trials (such as acute coronary syndromes (ACS) and stroke) from a physicians' perspective. Methods A standardised anonymous 14-item questionnaire was distributed to Polish cardiac and stroke centres. Results Two hundred and fourteen informative investigator responses were received. Of these investigators, 73.8% had experience with ACS and 25.2% had experience with acute stroke trials (and 1% with both fields). The complete model of informed consent (embracing all aspects required by Good Clinical Practice (GCP) and law) was used in 53.3% of cases in emergency settings, whereas the legal option of proxy consent was not used at all. While less than 15% of respondents considered written information to have been fully read by patients, 80.4% thought that the amount of information being given to emergency patients is too lengthy. Although there is no legal obligation, more than half of the investigators sought parallel consent (assent) from patients' relatives. Most investigators confirmed that they would adopt the model proposed by the GCP guidelines: abbreviated verbal and written consent in emergency conditions with obligatory "all-embracing" deferred consent to continue the trial once the patient is able to provide it. However, this model would not follow current Polish and European legislation. Conclusion An update of national and European regulations is required to enable implementation of the emergency trial consent model referred to in GCP guidelines. PMID:18644120

  14. 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

  15. A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

    PubMed Central

    Cheng, Cheng; Kuang, Lian-qin; Zhang, Yu-long; Cheng, Hai-yun; Min, Jia-yan; Wang, Yi

    2015-01-01

    Purpose. Manganese-enhanced MRI (MEMRI) has been applied to a wide range of biological and disease research. The purpose of the study was to use MEMRI to diagnose the acute mesenteric ischemia (AMI). Methods. The institutional experimental animal ethics committee approved this study. To optimize the dose of Mn2+ infusion, a dose-dependent curve was obtained using Mn2+-enhanced T1 map MRI by an intravenous infusion 2.5–20 nmol/g body weight (BW) of 50 nmol/L MnCl2. The eighteen animals were divided into control, sham-operated, and AMI groups. AMI models were performed by ligating the superior mesenteric artery (SMA). T1 values were measured on T1 maps in regions of the small intestinal wall and relaxation rate (ΔR1) was calculated. Results. A nonlinear relationship between infused MnCl2 solution dose and increase in small intestinal wall ΔR1 was observed. Control animal exhibited significant Mn2+ clearance over time at the dose of 15 nmol/g BW. In the AMI model, ΔR1 values (0.95 ± 0.13) in the small intestinal wall were significantly lower than in control group (2.05 ± 0.19) after Mn2+ infusion (P < 0.01). Conclusion. The data suggest that MEMRI shows potential as a diagnostic technique that is directly sensitive to the poor or absent perfusion in AMI. PMID:26693487

  16. Surveillance and expected outcome of acute lymphoblastic leukemia in children and adolescents: An experience from Eastern India

    PubMed Central

    Mukhopadhyay, Ashis; Gangopadhyay, Sudeshna; Dasgupta, Swati; Paul, Samrat; Mukhopadhyay, Soma; Ray, Ujjal Kanti

    2013-01-01

    Objective: Research in Eastern India especially among children and adolescents for acute lymphoblastic leukemia (ALL) have not been well documented until recently when it was conducted at a cancer institute of tertiary care with primary objectives of examining and correlating different cell surface markers involved with respect to disease surveillance thereby highlighting it as a strong prognostic marker for future diagnosis and treatment. Materials and Methods: A total of 500 consecutively selected ALL patients were diagnosed and treated according to National Cancer Institute protocol (MCP 841) for a period of 24-88 months during this hospital-based study. Results: Of the total, 50.4% had a higher incidence of T-ALL and 47.6% had pro-B, B-cell precursor ALL. Disease free survival and event free survival were remarkably higher in B-ALL adolescent patients as compared to T-ALL, who had significantly lower overall survival ratio. Prevalence of T-ALL was also observed in relapse cases for adolescent patients. Conclusions: We conclude that there is an increased prevalence of T-ALL among adolescents in Eastern India. Immunophenotypic analysis might help in proper evaluation and prediction of treatment outcomes with an increased thrust on studying age-specific incident rates enabling well planned future treatments for improved and better outcome. PMID:24604958

  17. Aetiologies of Acute Undifferentiated Febrile illness in Adult Patients – an Experience from a Tertiary Care Hospital in Northern India

    PubMed Central

    Ahmad, Sohaib; Agarwal, R K; Dhar, Minakshi; Mittal, Manish; Sharma, Shiwani

    2015-01-01

    Introduction Acute undifferentiated febrile illness (AUFI) is a common clinical entity in most of the hospitals. The fever can be potentially fatal if the aetiology is not recognized and appropriately treated early. Aim To describe the aetiology of fever among patients in a tertiary care hospital in Northern India. Materials and Methods A one-year retro-prospective, observational study was conducted in adults (age>18years) presenting with undifferentiated febrile illness (of duration 5-14 days). Diagnosis was confirmed by suitable laboratory tests after exhaustive clinical examination. Results A total of 2547 patients with AUFI were evaluated. Of these, 1663 (65.3%) were males and 884 (34.7%) were females. Dengue (37.54%); enteric fever (16.5%); scrub typhus (14.42%); bacterial sepsis (10.3%); malaria (6.8%); hepatitis A (1.9%); hepatitis E (1.4%); leptospirosis (0.14%); were the main infections while no specific diagnosis could be delineated in 11%. Mixed infections were noted in 48 (1.9%) patients. Conclusion A good clinical acumen supported by the basic investigations can help diagnose the cause of fever with reasonable certainty. PMID:26816892

  18. The Incidence of Hypersensitivity Reactions to Pegylated Asparaginase in Children With Acute Lymphoblastic Leukemia: A City-wide Experience.

    PubMed

    Alrazzak, Muaz; Beaupin, Lynda K; Kinyoun, Peter; Barth, Matthew

    2016-01-01

    Asparaginase (ASNase) is an imperative component of pediatric acute lymphoblastic leukemia (ALL) therapy. Pegylating the ASNase extends its biological half-life in vivo and has become the only ASNase available in the United States for frontline therapy of ALL and lymphoblastic lymphoma. It is either infused intravenously (IV) or injected intramuscularly (IM), administrations of which are associated with hypersensitivity reaction ranging from localized skin reaction to severe anaphylaxis. A retrospective review of 96 medical records of pediatric ALL patients was performed. We compared the incidence of hypersensitivity reaction associated with IV versus IM administration of pegylated ASNase. Ninety-one patients were included in the final analysis; 31 having received pegylated ASNase IV and 60 receiving it IM. The incidence of any grade ≥ 2 hypersensitivity reaction in patients who received IV ASNase was 32.2% compared with 13.3% in the IM group (P=0.032). There was no difference in higher grade hypersensitivity reactions (19.4% vs. 11.7%). Most reactions tended to occur during periods of leukemia therapy that did not include concomitant steroid therapy. Our retrospective analysis indicates that IV administration of pegylated ASNase increases the incidence of low-grade, but not grade 3-4, hypersensitivity reactions compared with IM administration. PMID:26558809

  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. PMID:26157385

  20. 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

  1. Simulations of complex and microscopic models of cardiac electrophysiology powered by multi-GPU platforms.

    PubMed

    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

  2. Chronic cranial window with access port for repeated cellular manipulations, drug application, and electrophysiology.

    PubMed

    Roome, Christopher J; Kuhn, Bernd

    2014-01-01

    Chronic cranial windows have been instrumental in advancing optical studies in vivo, permitting long-term, high-resolution imaging in various brain regions. However, once a window is attached it is difficult to regain access to the brain under the window for cellular manipulations. Here we describe a simple device that combines long term in vivo optical imaging with direct brain access via glass or quartz pipettes and metal, glass, or quartz electrodes for cellular manipulations like dye or drug injections and electrophysiological stimulations or recordings while keeping the craniotomy sterile. Our device comprises a regular cranial window glass coverslip with a drilled access hole later sealed with biocompatible silicone. This chronic cranial window with access port is cheap, easy to manufacture, can be mounted just as the regular chronic cranial window, and is self-sealing after retraction of the pipette or electrode. We demonstrate that multiple injections can be performed through the silicone port by repetitively bolus loading calcium sensitive dye into mouse barrel cortex and recording spontaneous cellular activity over a period of weeks. As an example to the extent of its utility for electrophysiological recording, we describe how simple removal of the silicone seal can permit patch pipette access for whole-cell patch clamp recordings in vivo. During these chronic experiments we do not observe any infections under the window or impairment of animal health. PMID:25426027

  3. Chronic cranial window with access port for repeated cellular manipulations, drug application, and electrophysiology

    PubMed Central

    Roome, Christopher J.; Kuhn, Bernd

    2014-01-01

    Chronic cranial windows have been instrumental in advancing optical studies in vivo, permitting long-term, high-resolution imaging in various brain regions. However, once a window is attached it is difficult to regain access to the brain under the window for cellular manipulations. Here we describe a simple device that combines long term in vivo optical imaging with direct brain access via glass or quartz pipettes and metal, glass, or quartz electrodes for cellular manipulations like dye or drug injections and electrophysiological stimulations or recordings while keeping the craniotomy sterile. Our device comprises a regular cranial window glass coverslip with a drilled access hole later sealed with biocompatible silicone. This chronic cranial window with access port is cheap, easy to manufacture, can be mounted just as the regular chronic cranial window, and is self-sealing after retraction of the pipette or electrode. We demonstrate that multiple injections can be performed through the silicone port by repetitively bolus loading calcium sensitive dye into mouse barrel cortex and recording spontaneous cellular activity over a period of weeks. As an example to the extent of its utility for electrophysiological recording, we describe how simple removal of the silicone seal can permit patch pipette access for whole-cell patch clamp recordings in vivo. During these chronic experiments we do not observe any infections under the window or impairment of animal health. PMID:25426027

  4. 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.

  5. [Value of functional and electrophysiological studies in amblyopia].

    PubMed

    Korol, S; Fiore, C

    1976-04-01

    In a group of patients suffering from amblyopia, the authors confront the results after orthoptic treatment with data provided by functional and electrophysiological examination. In 37 patients the clinical diagnosis of functional amblyopia had been made, but in 8 of these cases complimentary functional and electrophysiological examinations showed organic perturbations. This explains the failure, in these cases, of the orthoptic treatment. In the remaining 29 patients, clinical forms of functional amblyopia were found. In this group, the authors studied 20 cases showing no improvement with treatment: in 15 out of the 20 the VERs were pathological. In the 9 remaining cases which have showed improvement the VER'S were never abnormal. VER study can be undertaken, without general anaesthesia, as from 3 to 4 years of age. The authors conclude that all clinical forms of amblyopia should undergo VER investigation: patients showing pathological changes should be excluded from orthoptic treatment, from which they have no possibility of deriving benefit. PMID:135545

  6. Windows software for cardiac electrophysiology studies and ablation monitoring.

    PubMed

    Vänttinen, H; Nousiainen, J; Mäkynen, P; Malmivuo, J

    2000-03-01

    A system for cardiac electrophysiology (EP) studies consisting of a Windows software package, a standard 120 MHz Pentium PC with a high-performance video card and a data acquisition card has been developed during this study. The system is capable of real time data acquisition and storage of 24 channels with simultaneous display of 1-16 arbitrarily chosen channels at a sampling rate of 500 Hz. It can be used clinically in electrophysiology studies and during catheter radio-frequency ablation treatment for monitoring the ablation and its effects. The built-in ablation monitoring capability enables combined EP study and ablation treatment, thus helping to reduce exposure times and the total time needed per patient. For clinical use the software includes versatile tools for data analysis and reduction. Our system has been developed in association with Department of Cardiology of Tampere University Hospital and has been in regular clinical use there. PMID:10710184

  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. PMID:19059693

  8. A comparison of solver performance for complex gastric electrophysiology models.

    PubMed

    Sathar, Shameer; Cheng, Leo K; Trew, Mark L

    2015-08-01

    Computational techniques for solving systems of equations arising in gastric electrophysiology have not been studied for efficient solution process. We present a computationally challenging problem of simulating gastric electrophysiology in anatomically realistic stomach geometries with multiple intracellular and extracellular domains. The multiscale nature of the problem and mesh resolution required to capture geometric and functional features necessitates efficient solution methods if the problem is to be tractable. In this study, we investigated and compared several parallel preconditioners for the linear systems arising from tetrahedral discretisation of electrically isotropic and anisotropic problems, with and without stimuli. The results showed that the isotropic problem was computationally less challenging than the anisotropic problem and that the application of extracellular stimuli increased workload considerably. Preconditioning based on block Jacobi and algebraic multigrid solvers were found to have the best overall solution times and least iteration counts, respectively. The algebraic multigrid preconditioner would be expected to perform better on large problems. PMID:26736543

  9. Haemodialysis for paediatric acute kidney injury in a low resource setting: experience from a tertiary hospital in South West Nigeria

    PubMed Central

    Asinobi, Adanze O.; Ademola, Adebowale D.; Alao, Michael A.

    2016-01-01

    Background Acute kidney injury (AKI) is an important cause of preventable mortality among children. Management of AKI may require renal replacement therapy (RRT) but access to RRT for children in low resource settings is limited. Our study explored the role of haemodialysis in the management of children with AKI in a low resource setting in terms of aetiology and outcomes. Methods A review of patients managed in the Paediatric Nephrology Unit, University College Hospital Ibadan, South-West Nigeria, who underwent haemodialysis for AKI from January 2006 to December 2014. Results Sixty-eight patients (55.9% males), aged 3–16 (mean ± standard deviation, 9.0 ± 3.4) years were studied. The causes of AKI were sepsis (22.1%), malaria (17.6%) and glomerulonephritis (17.6%), intravascular haemolysis—cause unknown (16.2%), G6PDH deficiency (7.4%), malignancy (8.8%) and haemoglobinopathy (5.9%). The number of sessions of haemodialysis ranged from 1 to 10 (mode = 2 sessions) over a period of 1–55 days. Mortality was 27.9% (n = 19) and was related to the aetiology of AKI (P = 0.000): no deaths among patients with intravascular haemolysis or malaria, six deaths among patients with sepsis (40%), six (50%) among the patients with glomerulonephritis, while all the patients with malignancies died. Conclusions The outcome of haemodialysis for AKI in Nigeria is relatively good and is related to the underlying aetiology of AKI. In addition to peritoneal dialysis, intermittent haemodialysis may have a role in the management of paediatric AKI in low resource settings and should be supported. PMID:26798463

  10. Is there an increased risk of metabolic syndrome among childhood acute lymphoblastic leukemia survivors? A developing country experience.

    PubMed

    Mohapatra, Sonali; Bansal, Deepak; Bhalla, A K; Verma Attri, Savita; Sachdeva, Naresh; Trehan, Amita; Marwaha, R K

    2016-03-01

    Data on metabolic syndrome (MS) in survivors of childhood acute lymphoblastic leukemia (ALL) from developing countries are lacking. The purpose of this single-center, uncontrolled, observational study was to assess the frequency of MS in our survivors. The survivors of ALL ≤15 years at diagnosis, who had completed therapy ≥2 years earlier, were enrolled. Anthropometric measurements (weight, height, waist circumference), biochemistry (glucose, insulin, triglycerides, high-density lipoprotein [HDL], thyroid function tests, C-reactive protein [CRP], magnesium), measurement of blood pressure, and Tanner staging were performed. MS was defined by International Diabetes Federation (IDF) and the National Cholesterol Education Program Third Adult Treatment Panel guidelines (NCEP ATP III) criteria, modified by Cook et al. (Arch Pediatr Adolesc Med. 2003;157:821-827) and Ford et al. (Diabetes Care. 2005;28:878-881). The median age of 76 survivors was 11.9 years (interquartile range [IQR]: 9.6-13.5). Twenty-four (32%) survivors were obese or overweight. The prevalence of insulin resistance (17%), hypertension (7%), hypertriglyceridemia (20%), and low HDL (37%) was comparable to the prevalence in children/adolescents in historical population-based studies from India. The prevalence of MS ranged from 1.3% to 5.2%, as per different defining criteria. Cranial radiotherapy, age at diagnosis, sex, or socioeconomic status were not risk factors for MS. The prevalence of MS in survivors of childhood ALL, at a median duration of 3 years from completion of chemotherapy, was comparable to the reference population. The prevalence of being obese or overweight was, however, greater than historical controls. PMID:26984439

  11. Clinical pathway for acute exacerbations of chronic obstructive pulmonary disease: method development and five years of experience

    PubMed Central

    Nishimura, Koichi; Yasui, Maya; Nishimura, Takashi; Oga, Toru

    2011-01-01

    Background Randomized controlled trials, evidence-based medicine, clinical guidelines, and total quality management are some of the approaches used to render science-based health care services. The clinical pathway for hospitalized patients suffering from acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is poorly established, although a clinical pathway is an integral part of total quality management. Aim To evaluate the outcomes of patients hospitalized with AECOPD in Japan, treated with a clinical pathway following published guidelines. Methods Prospective data were collected for patients with AECOPD admitted to a general hospital over a 5-year period since 2003. The clinical pathway was designed to establish general rules for the entire treatment protocol. The clinical pathway indicates which treatments and interventions should be performed, and when. In this study, health care providers were required to check the clinical pathway sheets to determine the next step of treatment. Results This study analyzed 276 hospitalizations in 165 patients. The clinical pathway was interrupted and defined as a dropout in 45 cases (16.3%). Nine patients died during hospitalization (3.3%). Oxygen was administered in 232 hospitalizations (84.1%). Noninvasive positive pressure ventilation (NPPV) treatment was administered in 110 hospitalizations (39.9%). The rate of intubation in those cases where NPPV treatment had been administered was 8.2% (9 cases out of 110). The average length of stay (LOS) was 20.3 days, and the median value was 15 days. The LOS was longer than 30 days in 34 admissions (12.3%), mainly due to complications. Conclusion AECOPD can be managed using a clinical pathway. This clinical pathway could fill the gap between guidelines and clinical practice. PMID:21760723

  12. Gastrointestinal Fistulas in Acute Pancreatitis With Infected Pancreatic or Peripancreatic Necrosis: A 4-Year Single-Center Experience.

    PubMed

    Jiang, Wei; Tong, Zhihui; Yang, Dongliang; Ke, Lu; Shen, Xiao; Zhou, Jing; Li, Gang; Li, Weiqin; Li, Jieshou

    2016-04-01

    Gastrointestinal (GI) fistula is a well-recognized complication of acute pancreatitis (AP). However, it has been reported in limited literature. This study aimed to evaluate the incidence and outcome of GI fistulas in AP patients complicated with infected pancreatic or peripancreatic necrosis (IPN).Between 2010 and 2013 AP patients with IPN who diagnosed with GI fistula in our center were analyzed in this retrospective study. And we also conducted a comparison between patients with and without GI fistula regarding the baseline characteristics and outcomes.Over 4 years, a total of 928 AP patients were admitted into our center, of whom 119 patients with IPN were diagnosed with GI fistula and they developed 160 GI fistulas in total. Colonic fistula found in 72 patients was the most common form of GI fistula followed with duodenal fistula. All duodenal fistulas were managed by nonsurgical management. Ileostomy or colostomy was performed for 44 (61.1%) of 72 colonic fistulas. Twenty-one (29.2%) colonic fistulas were successfully treated by percutaneous drainage or continuous negative pressure irrigation. Mortality of patients with GI fistula did not differ significantly from those without GI fistula (28.6% vs 21.9%, P = 0.22). However, a significantly higher mortality (34.7%) was observed in those with colonic fistula.GI fistula is a common finding in patients of AP with IPN. Most of these fistulas can be successfully managed with different procedures depending on their sites of origin. Colonic fistula is related with higher mortality than those without GI fistula. PMID:27057908

  13. Treatment of Acute Graft-versus-Host Disease in Childhood with Extracorporeal Photochemotherapy/Photopheresis: The Padova Experience.

    PubMed

    Calore, Elisabetta; Marson, Piero; Pillon, Marta; Tumino, Manuela; Tison, Tiziana; Mainardi, Chiara; De Silvestro, Giustina; Rossin, Sara; Franceschetto, Genny; Carraro, Elisa; Pescarin, Matilde; Varotto, Stefania; Destro, Roberta; Gazzola, Maria Vittoria; Basso, Giuseppe; Messina, Chiara

    2015-11-01

    Acute graft-versus-host disease (aGVHD) is the major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Systemic steroid treatment represents the first-line therapy for aGVHD and is associated with a response rate of 30% to 60%. Steroid-resistant patients have a poor prognosis with high transplantation-related mortality (TRM). Several second-line therapies have been proposed for the management of unresponsive aGVHD, without proven beneficial effects on patients' outcome or overall long-term survival. For these reasons, extracorporeal photochemotherapy/photopheresis (ECP), a cell-based approach to control GVHD that spares generalized immunosuppression, seems to be promising. In this study, we report the outcome of 72 consecutive pediatric patients treated with ECP between 1997 and 2013 for aGVHD. Among them, 21 patients had steroid-resistant aGVHD, 42 had steroid-dependent aGVHD, and 9 did not receive steroid as first-line therapy because of clinical contraindications. A complete response was obtained in 72% of patients, a partial response was observed in 11%, and there was no response in 17% of patients. At day +180, TRM was 4% in the whole cohort; TRM was 3% and 20% among responders and nonresponders to ECP, respectively (P < .0001). The 5-year overall survival was 71%, showing a difference between responders and nonresponders of 78% and 30%, respectively (P = .0004). The 5-year time to progression of primary disease was 81%, without any significant difference between the 2 groups. Moreover, the 5-year progression-free survival of primary disease was 72%, with a significant difference (P = .0007) between responders (79%) and nonresponders (30%) to ECP. In conclusion, this study demonstrates that ECP is highly effective in aGVHD without a negative impact on primary disease. PMID:26183078

  14. 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.

  15. From Galvani to patch clamp: the development of electrophysiology.

    PubMed

    Verkhratsky, Alexei; Krishtal, O A; Petersen, Ole H

    2006-12-01

    The development of electrophysiology is traced from the early beginnings represented by the work of the Dutch microscopist, Jan Swammerdam, in the 17th century through the first notion of an aqueous transmembrane pore as a substrate of excitability made by Luigi Galvani in late 18th century to the invention late in the 20th century of the patch-clamp technique by Erwin Neher and Bert Sakmann. PMID:17072639

  16. The Simon effect in cognitive electrophysiology: A short review.

    PubMed

    Leuthold, Hartmut

    2011-02-01

    In the Simon task, stimuli are presented laterally and typically a non-spatial stimulus dimension demands a lateralized choice response. Responses are faster when the task-irrelevant stimulus location and the response location correspond than when they do not correspond. The present paper explores the impact of the Simon task on cognitive electrophysiological research as well as the insights gained from event-related brain potentials (ERPs) in the attempt to uncover the hidden mechanisms underlying the Simon effect. PMID:20828671

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

    PubMed Central

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

    2016-01-01

    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. PMID:27052791

  18. 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.

  19. 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. PMID:26840918

  20. [Electrophysiological evaluation of pathophysiological and pharmacological characteristics of chronic pain].

    PubMed

    Tanabe, Mitsuo

    2014-01-01

    Recent studies have revealed considerable evidence for our understanding of the mechanisms underlying the development and maintenance of chronic pain including neuropathic and inflammatory pain. It is considered that plastic changes in the spinal dorsal horn contribute to the amplification of pain signaling. Moreover, persistent pain affects brain function and also the endogenous descending pain regulatory system. To characterize these pathophysiological changes and pharmacological properties in chronic pain conditions at the synaptic level, we have employed in vitro electrophysiology in slices of the spinal cord and supraspinal regions such as brainstem and hippocampus of adult mice and in vivo electrophysiology in anesthetized rats. In particular, we have successfully prepared spinal slices with an attached dorsal root, where A-fiber- or C-fiber-evoked monosynaptic excitatory postsynaptic currents or miniature excitatory postsynaptic currents were recorded from voltage-clamped dorsal horn neurons. In anesthetized rats, C-fiber-evoked field potentials were recorded from the spinal dorsal horn in response to electrical stimulation of the sciatic nerve fibers, and their long-term potentiation was elicited to mimic increased synaptic efficacy after peripheral nerve injury. Of interest is the finding that some drugs exerted the injury-specific effects on synaptic transmission, thus strongly suggesting the importance of pharmacological analysis at the synaptic level combined with electrophysiological techniques to obtain pathophysiological information and new insights into drug research in this field. PMID:24584022

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

    PubMed

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

    2016-01-01

    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. PMID:27052791

  2. Executive function and endocrinological responses to acute resistance exercise

    PubMed Central

    Tsai, Chia-Liang; Wang, Chun-Hao; Pan, Chien-Yu; Chen, Fu-Chen; Huang, Tsang-Hai; Chou, Feng-Ying

    2014-01-01

    This study had the following two aims: First, to explore the effects of acute resistance exercise (RE, i.e., using exercise machines to contract and stretch muscles) on behavioral and electrophysiological performance when performing a cognitive task involving executive functioning in young male adults; Second, to investigate the potential biochemical mechanisms of such facilitative effects using two neurotrophic factors [i.e., growth hormone (GH) and insulin-like growth factor-1 (IGF-1)] and the cortisol levels elicited by such an exercise intervention mode with two different exercise intensities. Sixty young male adults were recruited and randomly assigned to a high-intensity (HI) exercise group, moderate-intensity (MI) exercise group, and non-exercise-intervention (NEI) group. Blood samples were taken, and the behavioral and electrophysiological indices were simultaneously measured when individuals performed a Go/No-Go task combined with the Erikson Flanker paradigm at baseline and after either an acute bout of 30 min of moderate- or high-intensity RE or a control period. The results showed that the acute RE could not only benefit the subjects' behavioral (i.e., RTs and accuracy) performance, as found in previous studies, but also increase the P3 amplitude. Although the serum GH and IGF-1 levels were significantly increased via moderate or high intensity RE in both the MI and HI groups, the increased serum levels of neurotrophic factors were significantly decreased about 20 min after exercise. In addition, such changes were not correlated with the changes in cognitive (i.e., behavioral and electrophysiological) performance. In contrast, the serum levels of cortisol in the HI and MI groups were significantly lower after acute RE, and the changes in cortisol levels were significantly associated with the changes in electrophysiological (i.e., P3 amplitude) performance. The findings suggest the beneficial effects of acute RE on executive functioning could be due to

  3. 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

  4. Acute treatment of atrial fibrillation.

    PubMed

    Kowey, P R; Marinchak, R A; Rials, S J; Filart, R A

    1998-03-12

    Atrial fibrillation (AFib) is a common clinical entity, responsible for significant morbidity and mortality, but it also accounts for a large percentage of healthcare dollar expenditures. Efforts to treat this arrhythmia in the past have focused on subacute antithrombotic therapy and eventually use of antiarrhythmic drugs for maintenance of sinus rhythm. However, there has been a growing interest in the concept of acute electrical and pharmacologic conversion. This treatment strategy has a number of benefits, including immediate alleviation of patient symptoms, avoidance of antithrombotic therapy, and prevention of electrophysiologic remodeling, which is thought to contribute to the perpetuation of the arrhythmia. There is also increasing evidence that this is a cost-effective strategy in that it may obviate admission to the hospital and the cost of long-term therapy. This article represents a summary of the treatments that may be used acutely to control the ventricular response to AFib, prevent thromboembolic events, and provide for acute conversion either pharmacologically or electrically. It includes information on modalities that are currently available and those that are under active development. We anticipate that an active, acute treatment approach to AFib and atrial flutter will become the therapeutic norm in the next few years, especially as the benefits of these interventions are demonstrated in clinical trials. PMID:9525568

  5. [Negative symptoms of schizophrenia: from electrophysiology to electrotherapy].

    PubMed

    Micoulaud Franchi, J-A; Quiles, C; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    The aim of this review of the literature is to summarize the state of the knowledge concerning the relationship between negative symptoms in schizophrenia, electrophysiology and electrotherapy. The scientific literature search of international articles was performed during August and September 2015 using the PubMed electronic database. We used the following MeSH terms: "Negative symptoms", "Schizophrenia", "Electrophysiology", "Neurophysiology", "EEG power", "Alpha rhythm", "Transcranial magnetic stimulation", "Transcranial direct current stimulation", "Electroconvulsive therapy", "Neurofeedback", "Vagus Nerve Stimulation", "Deep Brain Stimulation", and "State dependent". Negative symptoms in schizophrenia are associated with altered activity in prefrontal cortex in functional neuroimaging studies. This is in line with electrophysiological measurements that found a change in EEG spectral power in the alpha frequency band over prefrontal brain regions. The notion of functional hypofrontality has led to hypotheses that electrotherapy applied to the prefrontal cortex may be an effective treatment of negative symptoms in schizophrenia. Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) were used to increase cortical activity in schizophrenia and achieve a clinical effect on negative symptoms. Three meta-analyses confirmed, with a moderate effect size, that rTMS is an effective treatment option for negative symptoms in schizophrenia. The two subsequently published prospective multicenter studies, however, found opposite results from each other. Two randomized controlled studies suggested that tDCS is an effective treatment option for negative symptoms. There is no study on the efficacy of neurofeedback, vagal nerve stimulation or deep brain stimulation on negative symptoms in schizophrenia. Additional studies are needed to confirm the efficacy of rTMS and tDCS on negative symptoms in schizophrenia. Influencing factors

  6. Early rearing experience is associated with vasopressin immunoreactivity but not reactivity to an acute non-social stressor in the prairie vole.

    PubMed

    Perkeybile, Allison M; Bales, Karen L

    2015-08-01

    The early life experiences of an organism have the potential to alter its 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

  7. 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

  8. 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

  9. Applications of intraoperative ultrasound in the treatment of complicated cases of acute and chronic pancreatitis and pancreatic cancer – own experience

    PubMed Central

    Solecki, Michał; Wallner, Grzegorz

    2015-01-01

    Both acute and chronic inflammation of the pancreas often lead to complications that nowadays can be resolved using endoscopic and surgical procedures. In many cases, intraoperative ultrasound examination (IOUS) enables correct assessment of the extent of the lesion, and allows for safe surgery, while also shortening its length. Aim of the research At the authors’ clinic, intraoperative ultrasound is performed in daily practice. In this paper, we try to share our experiences in the application of this particular imaging technique. Research sample and methodology Intraoperative examination conducted by a surgeon who has assessed the patient prior to surgery, which enabled the surgeon to verify the initial diagnosis. The material presented in this paper includes 145 IOUS procedures performed during laparotomy due to lesions of the pancreas, 57 of which were carried out in cases of inflammatory process. Results and conclusions IOUS is a reliable examination tool in the evaluation of acute inflammatory lesions in the pancreas, especially during the surgery of chronic, symptomatic inflammation of the organ. The procedure allows for a correct determination of the necessary scope of the planned surgery. The examination allows for the differentiation between cystic lesions and tumors of cystic nature, dictates the correct strategy for draining, as well as validates the indications for the lesion's surgical removal. IOUS also allows the estimation of place and scope of drainage procedures in cases of overpressure in the pancreatic ducts caused by calcification of the parenchyma or choledocholitiasis in chronic pancreatitis. In pancreatic cancer, IOUS provides a verification of the local extent of tumor-like lesions, allowing for the assessment of pancreatic and lymph nodes metastasis, and indicating the presence of distant and local metastases, including the liver. IOUS significantly improves the effectiveness of intraoperative BAC aspiration or drainage of fluid

  10. 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

  11. 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.

  12. Acute Bronchitis

    MedlinePlus

    Bronchitis is an inflammation of the bronchial tubes, the airways that carry air to your lungs. It ... chest tightness. There are two main types of bronchitis: acute and chronic. Most cases of acute bronchitis ...

  13. Electrophysiological measures of language processing in bilinguals.

    PubMed

    Proverbio, Alice Mado; Cok, Barbara; Zani, Alberto

    2002-10-01

    The aim of the present study was to investigate how multiple languages are represented in the human brain. Event-related brain potentials (ERPs) were recorded from right-handed polyglots and monolinguals during a task involving silent reading. The participants in the experiment were nine Italian monolinguals and nine Italian/Slovenian bilinguals of a Slovenian minority in Trieste; the bilinguals, highly fluent in both languages, had spoken both languages since birth. The stimuli were terminal words that would correctly complete a short, meaningful, previously shown sentence, or else were semantically or syntactically incorrect. The task consisted in deciding whether the sentences were well formed or not, giving the response by pressing a button. Both groups read the same set of 200 Italian sentences to compare the linguistic processing, while the bilinguals also received a set of 200 Slovenian sentences, comparable in complexity and length, to compare the processing of the two languages within the group. For the bilinguals, the ERP results revealed a strong, left-sided activation, reflected by the N1 component, of the occipitotemporal regions dedicated to orthographic processing, with a latency of about 150 msec for Slovenian words, but bilateral activation of the same areas for Italian words, which was also displayed by topographical mapping. In monolinguals, semantic error produced a long-lasting negative response (N2 and N4) that was greater over the right hemisphere, whereas syntactic error activated mostly the left hemisphere. Conversely, in the bilinguals, semantic incongruence resulted in greater response over the left hemisphere than over the right. In this group, the P615 syntactical error responses were of equal amplitude on both hemispheres for Italian words and greater on the right side for Slovenian words. The present findings support the view that there are interand intrahemispheric brain activation asymmetries when monolingual and bilingual speakers

  14. 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

  15. Radiation exposure of an anaesthesiologist in catheterisation and electrophysiological cardiac procedures.

    PubMed

    Andreoli, Stefano; Moretti, Renzo; Lorini, Ferdinando Luca; Lagrotta, Mariavittoria

    2016-01-01

    Sometimes, cardiac catheterisation and electrophysiological procedures, diagnostic and interventional, require an anaesthesiological support. The anaesthesiologist receives radiation doses depending on various factors, such as type of procedure and exposure modality, anaesthesiological technique, individual protective devices and operator experience. The aim of this study was to investigate the dose per procedure, the exposure inhomogeneity and the effective dose, E, of a senior anaesthesiologist in the haemodynamic laboratory of Ospedali Riuniti, Bergamo. The dose monitoring was routinely performed with sets of several thermoluminescent dosemeters and an electronic personal dosemeter. The study covered 300 consecutive procedures over 1 y. The anaesthesiologist wore a protective apron, a thyroid collar and glasses (0.5 mm lead-equivalent). PMID:25752757

  16. Using Extracellular Single-unit Electrophysiological Data as a Substrate for Investigative Laboratory Exercises.

    PubMed

    Cousens, Graham A; Muir, Gary M

    2006-01-01

    Desirable objectives for laboratory-based science courses include fostering skills in problem solving and reasoning, enhancing data fluency, and encouraging consideration of science as an integrative enterprise. An effective means of reaching these objectives is to structure learning experiences around interesting problems in our own research. In this article, we explore the idea of using extracellular single-unit electrophysiological data as a substrate for student investigatory exercises as a means of achieving many of these objectives. In the article, we provide an overview of extracellular single-unit recording techniques and discuss the organization of single-unit data files. In addition, we describe a multi-week module recently administered in an intermediate-level laboratory course and provide suggestions both for more limited exercises and for more advanced projects. Finally, we describe a companion website that provides to instructors considering implementing similar exercises access to a variety of resources, including software, sample data, and additional information. PMID:23493564

  17. 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

  18. Fast Direct Injection Mass-Spectrometric Characterization of Stimuli for Insect Electrophysiology by Proton Transfer Reaction-Time of Flight Mass-Spectrometry (PTR-ToF-MS)

    PubMed Central

    Tasin, Marco; Cappellin, Luca; Biasioli, Franco

    2012-01-01

    Electrophysiological techniques are used in insect neuroscience to measure the response of olfactory neurons to volatile odour stimuli. Widely used systems to deliver an olfactory stimulus to a test insect include airstream guided flow through glass cartridges loaded with a given volatile compound on a sorbent support. Precise measurement of the quantity of compound reaching the sensory organ of the test organism is an urgent task in insect electrophysiology. In this study we evaluated the performances of the recent realised proton transfer reaction-time of flight mass-spectrometry (PTR-ToF-MS) as a fast and selective gas sensor. In particular, we characterised the gas emission from cartridges loaded with a set of volatile compounds belonging to different chemical classes and commonly used in electrophysiological experiments. PTR-ToF-MS allowed a fast monitoring of all investigated compounds with sufficient sensitivity and time resolution. The detection and the quantification of air contaminants and solvent or synthetic standards impurities allowed a precise quantification of the stimulus exiting the cartridge. The outcome of this study was twofold: on one hand we showed that PTR-ToF-MS allows monitoring fast processes with high sensitivity by real time detection of a broad number of compounds; on the other hand we provided a tool to solve an important issue in insect electrophysiology. PMID:22666020

  19. 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

  20. Incubator-independent cell-culture perfusion platform for continuous long-term microelectrode array electrophysiology and time-lapse imaging.

    PubMed

    Saalfrank, Dirk; Konduri, Anil Krishna; Latifi, Shahrzad; Habibey, Rouhollah; Golabchi, Asiyeh; Martiniuc, Aurel Vasile; Knoll, Alois; Ingebrandt, Sven; Blau, Axel

    2015-06-01

    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

  1. 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. PMID:26689544

  2. 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

  3. 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

  4. 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

  5. Brexpiprazole Alters Monoaminergic Systems following Repeated Administration: an in Vivo Electrophysiological Study

    PubMed Central

    Mansari, Mostafa El; Bundgaard, Christoffer; Blier, Pierre

    2016-01-01

    Background: Brexpiprazole was recently approved as adjunctive therapy for depression and treatment of schizophrenia in adults. To complement results from a previous study in which its acute effects were characterized, the present study assessed the effect of repeated brexpiprazole administration on monoaminergic systems. Methods: Brexpiprazole (1mg/kg, subcutaneous) or vehicle was administered once daily for 2 and 14 days. Single-unit electrophysiological recordings from noradrenaline neurons in the locus coeruleus, serotonin neurons in the dorsal raphe nucleus, dopaminergic neurons in the ventral tegmental area, and pyramidal neurons in the hippocampus CA3 region were obtained in adult male Sprague-Dawley rats under chloral hydrate anesthesia within 4 hours after final dosing. Results: Brexpiprazole blunted D2 autoreceptor responsiveness, while firing activity of ventral tegmental area dopaminergic neurons remained unaltered. Brexpiprazole increased the firing rate of locus coeruleus noradrenaline neurons and increased noradrenaline tone on α2-adrenergic receptors in the hippocampus. Administration of brexpiprazole for 2 but not 14 days increased the firing rate of serotonin neurons in the dorsal raphe nucleus. In the hippocampus, serotonin1A receptor blockade significantly disinhibited pyramidal neurons after 2- and 14-day brexpiprazole administration. In contrast, no significant disinhibition occurred after 24-hour washout or acute brexpiprazole. Conclusions: Repeated brexpiprazole administration resulted in a marked occupancy of D2 autoreceptors, while discharge activity of ventral tegmental area dopaminergic neurons remained unaltered. Brexpiprazole enhanced serotonergic and noradrenergic tone in the hippocampus, effects common to antidepressant agents. Together, these results provide further insight in the neural mechanisms by which brexpiprazole exerts antidepressant and antipsychotic effects. PMID:26428352

  6. Severe acute respiratory infections during the influenza A(H1N1)2009 pandemic in Belgium: first experience of hospital-based flu surveillance

    PubMed Central

    2010-01-01

    Introduction In September 2009, as part of the surveillance during the Influenza A(2009) pandemic, Bel-gium introduced a web-based surveillance system aimed at recording hospitalisations and deaths attributable to Influenza in real time. Methods We present the web-based application developed for the pandemic as well as a descriptive analysis of Severe Acute Respiratory Infection (SARI) cases reported through this system. Results From 1 September to 31 December 2009, 1723 SARI-related hospitalisations potentially due to influenza were reported in Belgium. The median age of the patients was 29 years (range: < 1 year-99 years). Among SARI-hospitalised patients 68% were aged less than 45 years, 10.6% were vaccinated with the seasonal influenza vaccine and 7.5% with the pandemic influenza vaccine. No deaths were recorded. Conclusions This first experience showed the feasibility of getting real-time information from hospitals during a public health crisis. However, the absence of death detected through the system highlighted the importance of better defining the severity of the hospital cases.

  7. 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

  8. Acute optic neuritis

    PubMed Central

    Galetta, Steven L.; Villoslada, Pablo; Levin, Netta; Shindler, Kenneth; Ishikawa, Hiroshi; Parr, Edward; Cadavid, Diego

    2015-01-01

    Idiopathic demyelinating optic neuritis (ON) most commonly presents as acute unilateral vision loss and eye pain and is frequently associated with multiple sclerosis. Although emphasis is often placed on the good recovery of high-contrast visual acuity, persistent deficits are frequently observed in other aspects of vision, including contrast sensitivity, visual field testing, color vision, motion perception, and vision-related quality of life. Persistent and profound structural and functional changes are often revealed by imaging and electrophysiologic techniques, including optical coherence tomography, visual-evoked potentials, and nonconventional MRI. These abnormalities can impair patients' abilities to perform daily activities (e.g., driving, working) so they have important implications for patients' quality of life. In this article, we review the sequelae from ON, including clinical, structural, and functional changes and their interrelationships. The unmet needs in each of these areas are considered and the progress made toward meeting those needs is examined. Finally, we provide an overview of past and present investigational approaches for disease modification in ON. PMID:26236761

  9. Cardiac electrophysiology numerical models using symmetric multiprocessing (SMP).

    PubMed

    Petsios, Stefanos Konstantinos D; Fotiadis, Dimitrios I

    2009-01-01

    Multi-dimensional electrophysiological models have been introduced to investigate electrical propagation in tissue level, based on cell-dynamics models. The models include a set of non-linear differential equations which describe the dynamics of cell and tissue excitation. However, as models evolve, it is inevitable that proper and powerful tools need to be introduced in order to reproduce the detailed and thus computationally intensive simulations. To build such tools, several computational methodologies need to be adopted regarding efficiency and reliability. On the other hand improvements apply to the hardware too. State of the art computers, even personal computers, tend to make use of multiple core Central Processing Units. Unfortunately the aforementioned methodologies follow sequential logic, resulting to low efficiency of the working platform. In this work we present the performance bottleneck in symmetric multiprocessing (SMP) for simulations of propagation phenomena in cardiac tissue electrophysiological models. We demonstrate the scalability and efficacy of the different methodologies used in the discretisation scheme and message passing in SMP. PMID:19965052

  10. Investigating the electrophysiological basis of resting state networks using magnetoencephalography

    PubMed Central

    Brookes, Matthew J.; Woolrich, Mark; Luckhoo, Henry; Price, Darren; Hale, Joanne R.; Stephenson, Mary C.; Barnes, Gareth R.; Smith, Stephen M.; Morris, Peter G.

    2011-01-01

    In recent years the study of resting state brain networks (RSNs) has become an important area of neuroimaging. The majority of studies have used functional magnetic resonance imaging (fMRI) to measure temporal correlation between blood-oxygenation-level–dependent (BOLD) signals from different brain areas. However, BOLD is an indirect measure related to hemodynamics, and the electrophysiological basis of connectivity between spatially separate network nodes cannot be comprehensively assessed using this technique. In this paper we describe a means to characterize resting state brain networks independently using magnetoencephalography (MEG), a neuroimaging modality that bypasses the hemodynamic response and measures the magnetic fields associated with electrophysiological brain activity. The MEG data are analyzed using a unique combination of beamformer spatial filtering and independent component analysis (ICA) and require no prior assumptions about the spatial locations or patterns of the networks. This method results in RSNs with significant similarity in their spatial structure compared with RSNs derived independently using fMRI. This outcome confirms the neural basis of hemodynamic networks and demonstrates the potential of MEG as a tool for understanding the mechanisms that underlie RSNs and the nature of connectivity that binds network nodes. PMID:21930901

  11. Multiscale Modeling of Gastrointestinal Electrophysiology and Experimental Validation

    PubMed Central

    Du, Peng; O'Grady, Greg; Davidson, John B.; Cheng, Leo K.; Pullan, Andrew J.

    2011-01-01

    Normal gastrointestinal (GI) motility results from the coordinated interplay of multiple cooperating mechanisms, both intrinsic and extrinsic to the GI tract. A fundamental component of this activity is an omnipresent electrical activity termed slow waves, which is generated and propagated by the interstitial cells of Cajal (ICCs). The role of ICC loss and network degradation in GI motility disorders is a significant area of ongoing research. This review examines recent progress in the multiscale modeling framework for effectively integrating a vast range of experimental data in GI electrophysiology, and outlines the prospect of how modeling can provide new insights into GI function in health and disease. The review begins with an overview of the GI tract and its electrophysiology, and then focuses on recent work on modeling GI electrical activity, spanning from cell to body biophysical scales. Mathematical cell models of the ICCs and smooth muscle cell are presented. The continuum framework of monodomain and bidomain models for tissue and organ models are then considered, and the forward techniques used to model the resultant body surface potential and magnetic field are discussed. The review then outlines recent progress in experimental support and validation of modeling, and concludes with a discussion on potential future research directions in this field. PMID:21133835

  12. Electrophysiological mechanisms of the SI SII SIII electrocardiographic morphology

    SciTech Connect

    Bayes de Luna, A.; Carrio, I.; Subirana, M.T.; Torner, P.; Cosin, J.; Sagues, F.; Guindo, J.

    1987-01-01

    We studied three groups of individuals by means of spatial-velocity electrocardiograms and thallium-201 myocardial imaging to figure out the electrophysiological explanation of the SI SII SIII electrocardiographic morphology. We studied twelve healthy individuals without SI SII SIII, seven healthy individuals with SI SII SIII and fifteen patients with chronic obstructive pulmonary disease with SI SII SIII. The average values of the QRS-E and QRS-F intervals were higher in the second and third groups than in the first. One patient of the second group and thirteen of the third showed right ventricular enlargement. The slowing down of the right ventricular conduction explained the SI SII SIII morphology in normal individuals in more than half the cases. In patients with chronic obstructive pulmonary disease with SI SII SIII the conduction delay plays an important part in the electrogenesis of the right ventricular enlargement electrocardiographic morphology. We think that these observations can give further data about the electrophysiologic mechanism of the SI SII SIII morphology.

  13. 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

  14. Simultaneous Electrophysiological Recording and Calcium Imaging of Suprachiasmatic Nucleus Neurons

    PubMed Central

    Irwin, Robert P.; Allen, Charles N.

    2013-01-01

    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 Ca2+ 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. PMID:24335611

  15. Electrophysiological Effects of Dexmedetomidine on Sinoatrial Nodes of Rabbits

    PubMed Central

    Pan, Xia; Zhang, Zhen; Huang, Ya-Yi; Zhao, Jing; Wang, Long

    2015-01-01

    Background The purpose of this study was to investigate the electrophysiological effects of dexmedetomidine on pacemaker cells in sinoatrial nodes of rabbits. Methods Healthy rabbits were anesthetized intravenously with sodium pentobarbital, and the hearts were quickly dissected and mounted in a tissue bath. Machine-pulled glass capillary microelectrodes which were connected to a high input impedance amplifier and impaled in dominant pacemaker cells. Thereafter, an intracellular microelectrode technique was used to record action potential. Results The amplitude of action potential, velocity of diastolic (phase 4) depolarization, and rate of pacemaker firing in normal pacemaker cells in sinoatrial node were decreased by use of dexmedetomidine (0.5 ng/ml, 5 ng/ml, 50 ng/ml) in a concentration-dependent manner. Pretreatment with yohimbine (1 μM), did not alter the effects of dexmedetomidine (5 ng/ml) on sinoatrial node pacemaker cells. Pretreatment with CsCl (2 mmol/L), dexmedetomidine (5 ng/ml) decreased the amplitude of action potential, but had no significant effect on other parameters of action potential. Conclusions Dexmedetomidine exerts inhibitory electrophysiological effects on pacemaker cells in sinoatrial nodes of rabbits in a concentration-dependent manner, which may not be mediated by alpha 2-adrenoreceptor. PMID:27122920

  16. 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. PMID:24259465

  17. Subjective Stress, Salivary Cortisol, and Electrophysiological Responses to Psychological Stress

    PubMed Central

    Qi, Mingming; Gao, Heming; Guan, Lili; Liu, Guangyuan; Yang, Juan

    2016-01-01

    The present study aimed to investigate the subjective stress, salivary cortisol, and electrophysiological responses to psychological stress induced by a modified version of a mental arithmetic task. Fifteen participants were asked to estimate whether the multiplication product of two-decimal numbers was above 10 or not either with a time limit (the stress condition) or without a time limit (the control condition). The results showed that participants reported higher levels of stress, anxiety, and negative affect in the stress condition than they did in the control condition. Moreover, the salivary cortisol level continued to increase after the stress condition but exhibited a sharp decrease after the control condition. In addition, the electrophysiological data showed that the amplitude of the frontal-central N1 component was larger for the stress condition than it was for the control condition, while the amplitude of the frontal-central P2 component was larger for the control condition than it was for the stress condition. Our study suggests that the psychological stress characteristics of time pressure and social-evaluative threat caused dissociable effects on perception and on the subsequent attentional resource allocation of visual information. PMID:26925026

  18. Relationship of Vascular Factors on Electrophysiologic Severity of Diabetic Neuropathy

    PubMed Central

    Hwang, Jeong-Won; Kwon, Hee Kyu

    2016-01-01

    Objective To investigate the impact of vascular factors on the electrophysiologic severity of diabetic neuropathy (DPN). Methods Total 530 patients with type 2 diabetes were enrolled retrospectively. We rated severity of DPN from 1 (normal) to 4 (severe) based on electrophysiologic findings. We collected the data concerning vascular factors (including brachial-ankle pulse wave velocity [PWV], ankle brachial index, ultrasound of carotid artery, lipid profile from the blood test, and microalbuminuria [MU] within 24 hours urine), and metabolic factors of diabetes (such as glycated hemoglobin [HbA1c]). We analyzed the differences among the four subgroups using χ2 test and ANOVA, and ordinal logistic regression analysis was performed to investigate the relationship between significant variables and severity of DPN. Results The severity of DPN was significantly associated with duration of diabetes, HbA1c, existence of diabetic retinopathy and nephropathy, PWV, presence of plaque, low density lipoprotein-cholesterol and MU (p<0.05). Among these variables, HbA1c and presence of plaque were more significantly related with severity of DPN in logistic regression analysis (p<0.001), and presence of plaque showed the highest odds ratio (OR=2.52). Conclusion Our results suggest that markers for vascular wall properties, such as PWV and presence of plaque, are significantly associated with the severity of DPN. The presence of plaque was more strongly associated with the severity of DPN than other variables. PMID:26949670

  19. Three electrophysiological phenotypes of cultured human umbilical vein endothelial cells.

    PubMed

    Yu, K; Ruan, D Y; Ge, S Y

    2002-09-01

    The conventional whole cell patch-clamp technique was used to measure the resting membrane conductance and membrane currents of nonstimulated cultured human umbilical vein endothelial cells (HUVECs) in different ionic conditions. Three electrophysiological phenotypes of cultured HUVECs (n = 122) were determined: first, 20% of cells as type I mainly displaying the inwardly rectifying potassium current (IKi); second, 38% of cells as type II in which IKi was super-posed on a TEA-sensitive, delayed rectifying current; third, 27% of cells as type III predominantly displaying the outwardly rectifying current which was sensitive to TEA and slightly inhibited by a chloride channel blocker niflumic acid (N.A.). In cells of type I, the mean zero-current potential (V0) was dependent on extracellular K+ ([K+]o) but not on Cl-, indicating major permeability to K+. Whereas V0 of type II was also affected by extracellular Cl- ([Cl-]o), indicating the contribution of an outward Cl- current in setting V0. The cells of type III were not sensitive to decrease of [Cl-]o and the outward current was activated in a relative stable voltage range. This varying phenotypic expression and multipotential behavior of HUVECs suggests that the electrical features of HUVEC may be primarily determined by embryonic origin and local effect of the microenvironment. This research provided the detailed electrophysiological knowledge of the endothelial cells. PMID:12537354

  20. Electrophysiological characteristics according to activity level of myofascial trigger points.

    PubMed

    Yu, Seong Hun; Kim, Hyun Jin

    2015-09-01

    [Purpose] This study compared the differences in electrophysiological characteristics of normal muscles versus muscles with latent or active myofascial trigger points, and identified the neuromuscular physiological characteristics of muscles with active myofascial trigger points, thereby providing a quantitative evaluation of myofascial pain syndrome and clinical foundational data for its diagnosis. [Subjects] Ninety adults in their 20s participated in this study. Subjects were equally divided into three groups: the active myofascial trigger point group, the latent myofascial trigger point group, and the control group. [Methods] Maximum voluntary isometric contraction (MVIC), endurance, median frequency (MDF), and muscle fatigue index were measured in all subjects. [Results] No significant differences in MVIC or endurance were revealed among the three groups. However, the active trigger point group had significantly different MDF and muscle fatigue index compared with the control group. [Conclusion] Given that muscles with active myofascial trigger points had an increased MDF and suffered muscle fatigue more easily, increased recruitment of motor unit action potential of type II fibers was evident. Therefore, electrophysiological analysis of these myofascial trigger points can be applied to evaluate the effect of physical therapy and provide a quantitative diagnosis of myofascial pain syndrome. PMID:26504306

  1. Electrophysiological characteristics according to activity level of myofascial trigger points

    PubMed Central

    Yu, Seong Hun; Kim, Hyun Jin

    2015-01-01

    [Purpose] This study compared the differences in electrophysiological characteristics of normal muscles versus muscles with latent or active myofascial trigger points, and identified the neuromuscular physiological characteristics of muscles with active myofascial trigger points, thereby providing a quantitative evaluation of myofascial pain syndrome and clinical foundational data for its diagnosis. [Subjects] Ninety adults in their 20s participated in this study. Subjects were equally divided into three groups: the active myofascial trigger point group, the latent myofascial trigger point group, and the control group. [Methods] Maximum voluntary isometric contraction (MVIC), endurance, median frequency (MDF), and muscle fatigue index were measured in all subjects. [Results] No significant differences in MVIC or endurance were revealed among the three groups. However, the active trigger point group had significantly different MDF and muscle fatigue index compared with the control group. [Conclusion] Given that muscles with active myofascial trigger points had an increased MDF and suffered muscle fatigue more easily, increased recruitment of motor unit action potential of type II fibers was evident. Therefore, electrophysiological analysis of these myofascial trigger points can be applied to evaluate the effect of physical therapy and provide a quantitative diagnosis of myofascial pain syndrome. PMID:26504306

  2. Use of electrophysiological monitoring in selective rhizotomy treating glossopharyngeal neuralgia.

    PubMed

    Zhang, Wenhao; Chen, Minjie; Zhang, Weijie; Chai, Ying

    2014-07-01

    The aim of this study was to evaluate the effects of electrophysiological monitoring on selective rhizotomy of the glossopharyngeal nerve (SRGN) in treatment of glossopharyngeal neuralgia (GPN). From December, 2009 to May, 2012, SRGN was carried out on 8 patients with GPN, through a suboccipital sigmoid sinus posterior approach. The electrodes were placed on the cricothyroid muscle (vagus nerve). Two groups of amplitudes (A1 and A2) were recorded. A1 was recorded when the mixed nerve root was stimulated, and A2 when the part of the vagus nerve was stimulated. The glossopharyngeal nerve was sectioned and the vagus nerve was preserved. If A1/A2 < 50%, the mixed nerve root should be sectioned, otherwise the mixed nerve root should be retained. As the representation of vagus nerve, the averages of A1 and A2 were 22 and 36 μV respectively. The 8 patients were followed up for 9-39 months. Seven patients (87.5%) obtained complete pain relief (excellent) without complications such as hoarseness, dysphagia, and cough. One case (12.5%) obtained moderate relief (good), and was under control with carbamazepine at a dosage of 600 mg/d. Cough was occurred in this patient, but relieved in two months. Electrophysiological monitoring in SRGN can improve the efficiency of pain relief and reduce the incidence of complications. PMID:24095216

  3. 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

  4. Electrophysiological study of intravenous pinaverium bromide in cardiology.

    PubMed

    Guerot, C; Khemache, A; Sebbah, J; Noel, B

    1988-01-01

    Pinaverium bromide is a musculotropic spasmolytic agent which acts by inhibiting transmembrane calcium movements, an effect similar to that of verapamil. Because of this, an investigation was carried out to see if it had any electrophysiological effects in patients with various cardiac disorders. In an open study, 10 patients received 2 mg pinaverium bromide intravenously. In a double-blind study, 10 patients received 4 mg pinaverium bromide intravenously and 10 patients placebo. Patients included those with either normal or pathological basal conduction, such as bundle-branch block and 1st degree atrioventricular block. Measurements were made of electrophysiological parameters before and 10 minutes after injection. The results showed that neither of the two doses of pinaverium bromide had any effect on atrial excitability, sino-atrial conduction, node and trunk atrioventricular conduction or on intraventricular conduction. No significant difference was seen in comparison with placebo. Pinaverium bromide had no anti-arrhythmic properties in these studies. Local, cardiac and general clinical tolerability was good in all patients. PMID:3219882

  5. 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. PMID:27512383

  6. Simulation Methods and Validation Criteria for Modeling Cardiac Ventricular Electrophysiology

    PubMed Central

    Krishnamoorthi, Shankarjee; Perotti, Luigi E.; Borgstrom, Nils P.; Ajijola, Olujimi A.; Frid, Anna; Ponnaluri, Aditya V.; Weiss, James N.; Qu, Zhilin; Klug, William S.; Ennis, Daniel B.; Garfinkel, Alan

    2014-01-01

    We describe a sequence of methods to produce a partial differential equation model of the electrical activation of the ventricles. In our framework, we incorporate the anatomy and cardiac microstructure obtained from magnetic resonance imaging and diffusion tensor imaging of a New Zealand White rabbit, the Purkinje structure and the Purkinje-muscle junctions, and an electrophysiologically accurate model of the ventricular myocytes and tissue, which includes transmural and apex-to-base gradients of action potential characteristics. We solve the electrophysiology governing equations using the finite element method and compute both a 6-lead precordial electrocardiogram (ECG) and the activation wavefronts over time. We are particularly concerned with the validation of the various methods used in our model and, in this regard, propose a series of validation criteria that we consider essential. These include producing a physiologically accurate ECG, a correct ventricular activation sequence, and the inducibility of ventricular fibrillation. Among other components, we conclude that a Purkinje geometry with a high density of Purkinje muscle junctions covering the right and left ventricular endocardial surfaces as well as transmural and apex-to-base gradients in action potential characteristics are necessary to produce ECGs and time activation plots that agree with physiological observations. PMID:25493967

  7. Electrophysiological white matter dysfunction and association with neurobehavioral deficits following low-level primary blast trauma.

    PubMed

    Park, Eugene; Eisen, Rebecca; Kinio, Anna; Baker, Andrew J

    2013-04-01

    There is strong evidence that primary blast injuries can cause neuropathological alterations in the brain. Clinical findings from war veterans indicating evidence of diffuse axonal injury have been corroborated by numerous primary blast models in animals. However, the effect of a subclinical blast (blast with no obvious sign of external trauma or lung injury) as a contributing factor to the neurological symptoms and neuropathology is less clear. Our group recently developed a model of low-level primary blast and characterized aberrant expression of white matter cytoskeletal proteins in the cortex and hippocampus following a subclinical wave shock exposure. Here we examined the susceptibility of the corpus callosum following subclinical blast. We also demonstrate that white matter dysfunction is associated with neurobehavioral deficits associated with anxiety and stress in rats. Anesthetized male Sprague-Dawley rats (~300 g) were exposed to a primary blast (approx. 28 kPa), below the threshold required to induce pulmonary trauma. Rats were evaluated on three behavioral outcome measures; the rotarod, the light/dark box and open field anxiety test. We used Western blotting to examine expression and degradation of axonally expressed αII-spectrin, NF200 and voltage-gated sodium channels (VGSC) in the corpus callosum. Acute slice preparations were used for electrophysiological analysis of evoked compound action potentials (CAPs) in the corpus callosum. There was evidence of αII-spectrin degradation in the corpus callosum at 48 h post-injury detectable up to 14 days post-injury, as well as increased heavy neurofilament expression. A reduction in VGSC expression was observed at 48 h post-blast as well as a reduction in the interaction between ankyrin G and intact αII-spectrin. Blast exposed rats had significantly lower rotarod latency times relative to sham rats (p=0.002). Increased anxiety-related and stress-related behavior were observed in blast rats relative to sham

  8. 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

  9. Alfaxalone Anaesthesia Facilitates Electrophysiological Recordings of Nociceptive Withdrawal Reflexes in Dogs (Canis familiaris).

    PubMed

    Hunt, James; Murrell, Jo; Knazovicky, David; Harris, John; Kelly, Sara; Knowles, Toby G; Lascelles, B Duncan X

    2016-01-01

    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

  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. 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

  12. 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. PMID:20598583

  13. 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…

  14. Acute nephritic syndrome

    MedlinePlus

    Glomerulonephritis - acute; Acute glomerulonephritis; Nephritis syndrome - acute ... Acute nephritic syndrome is often caused by an immune response triggered by an infection or other disease. Common causes ...

  15. Role of basiliximab in the prevention of acute cellular rejection in adult to adult living-related liver transplantation: a single center experience

    PubMed Central

    Gruttadauria, S; Mandalà, L; Biondo, D; Spampinato, M; Lamonaca, V; Volpes, R; Vizzini, G; Marsh, JW; Marcos, A; Gridelli, B

    2007-01-01

    We report our single center experience with the use of basiliximab, a chimeric monoclonal antibody directed against the alpha chain of the interleukin-2 (IL-2) receptor (CD25), in combination with a steroid- and tacrolimus-based regimen in adult to adult living-related liver transplantation (ALRLT). Sixty consecutive ALRLTs were analyzed. All patients received two 20-mg doses of basiliximab (days 0 and 4 after transplantation) followed by tacrolimus (0.15 mg/kg/day; 10–15 ng/mL target trough levels) and a dose regimen of steroids (starting with 20 mg iv, switched to po as soon as the patient was able to eat, and weaned off within 1–2 months). Follow-up ranged from 6 to 1699.4 days after transplantation (mean 517.5 days, SD ± 413.4; median 424 days). Of the recipients, 95% remained rejection-free during follow-up, with an actuarial rejection-free probability of 96.61% within 3 months. Three patients had episodes of biopsy-proven acute cellular rejection (ACR). Actuarial patient and graft survival rates at 3 years were 82.09% and 75.61%. Six patients (10%) experienced sepsis. There was no evidence of cytomegalovirus infections or side-effects related to the basiliximab. We found zero de novo malignancy, although we observed 5 patients with metastatic spread of their primary malignancy during the follow-up. Basiliximab in association with tacrolimus and steroids is effective in reducing episodes of ACR and increasing ACR-free survival after ALRLT. PMID:19707350

  16. Treatment with Low-Dose Cytarabine in Elderly Patients (Age 70 Years or Older) with Acute Myeloid Leukemia: A Single Institution Experience

    PubMed Central

    Heiblig, Maël; Elhamri, Mohamed; Tigaud, Isabelle; Plesa, Adriana; Barraco, Fiorenza; Labussière, Hélène; Ducastelle, Sophie; Michallet, Mauricette; Nicolini, Franck; Plesa, Claudiu; Wattel, Eric; Salles, Gilles; Thomas, Xavier

    2016-01-01

    Objectives Low-dose cytarabine (LD-AraC) is still regarded as the standard of care in elderly patients with acute myeloid leukemia (AML) ‘unfit’ for intensive chemotherapy. In this study, we reported our experience with LD-AraC in patients ≥ 70 years old and compared the results to those of intensive chemotherapy, best supportive care (BSC), or hypomethylating agents in the same age population. Methods Between 2000 and 2014, 60 patients received LD-AraC at 20 mg once or twice daily by subcutaneous injection for 10 consecutive days every 4–6 weeks. Results Complete remission rate with LD-AraC was 7% versus 56% with intensive chemotherapy and 21% with hypomethylating agents. Median overall survival (OS) of patients treated with LD-AraC was 9.6 months with 3-year OS of 12%. Survival with LD-AraC was better than with BSC only (P = 0.001). Although not statistically significant, intensive chemotherapy and hypomethylating agents tended to be better than LD-AraC in terms of OS (median: 12.4 months and 16.1 months, respectively). There was no clear evidence that a beneficial effect of LD-AraC was restricted to any particular subtype of patients, except for cytogenetics. There was a trend for a better OS in LD-AraC treated patients in the setting of clinical trials as compared with those treated outside of a clinical trial. Conclusions Despite a trend in favor of intensive chemotherapy and hypomethylating agents over LD-AraC, no real significant advantage could be demonstrated, while LD-AraC showed a significant advantage comparatively to BSC. All this tends to confirm that LD-AraC can still represent a baseline against which new promising agents may be compared either alone or in combination. PMID:26740870

  17. Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling.

    PubMed

    Brown, Sherry-Ann; Moraru, Ion I; Schaff, James C; Loew, Leslie M

    2011-10-01

    Because of its highly branched dendrite, the Purkinje neuron requires significant computational resources if coupled electrical and biochemical activity are to be simulated. To address this challenge, we developed a scheme for reducing the geometric complexity; while preserving the essential features of activity in both the soma and a remote dendritic spine. We merged our previously published biochemical model of calcium dynamics and lipid signaling in the Purkinje neuron, developed in the Virtual Cell modeling and simulation environment, with an electrophysiological model based on a Purkinje neuron model available in NEURON. A novel reduction method was applied to the Purkinje neuron geometry to obtain a model with fewer compartments that is tractable in Virtual Cell. Most of the dendritic tree was subject to reduction, but we retained the neuron's explicit electrical and geometric features along a specified path from spine to soma. Further, unlike previous simplification methods, the dendrites that branch off along the preserved explicit path are retained as reduced branches. We conserved axial resistivity and adjusted passive properties and active channel conductances for the reduction in surface area, and cytosolic calcium for the reduction in volume. Rallpacks are used to validate the reduction algorithm and show that it can be generalized to other complex neuronal geometries. For the Purkinje cell, we found that current injections at the soma were able to produce similar trains of action potentials and membrane potential propagation in the full and reduced models in NEURON; the reduced model produces identical spiking patterns in NEURON and Virtual Cell. Importantly, our reduced model can simulate communication between the soma and a distal spine; an alpha function applied at the spine to represent synaptic stimulation gave similar results in the full and reduced models for potential changes associated with both the spine and the soma. Finally, we combined

  18. Virtual NEURON: a strategy for merged biochemical and electrophysiological modeling

    PubMed Central

    Brown, Sherry-Ann; Moraru, Ion I.; Schaff, James C.

    2011-01-01

    Because of its highly branched dendrite, the Purkinje neuron requires significant computational resources if coupled electrical and biochemical activity are to be simulated. To address this challenge, we developed a scheme for reducing the geometric complexity; while preserving the essential features of activity in both the soma and a remote dendritic spine. We merged our previously published biochemical model of calcium dynamics and lipid signaling in the Purkinje neuron, developed in the Virtual Cell modeling and simulation environment, with an electrophysiological model based on a Purkinje neuron model available in NEURON. A novel reduction method was applied to the Purkinje neuron geometry to obtain a model with fewer compartments that is tractable in Virtual Cell. Most of the dendritic tree was subject to reduction, but we retained the neuron’s explicit electrical and geometric features along a specified path from spine to soma. Further, unlike previous simplification methods, the dendrites that branch off along the preserved explicit path are retained as reduced branches. We conserved axial resistivity and adjusted passive properties and active channel conductances for the reduction in surface area, and cytosolic calcium for the reduction in volume. Rallpacks are used to validate the reduction algorithm and show that it can be generalized to other complex neuronal geometries. For the Purkinje cell, we found that current injections at the soma were able to produce similar trains of action potentials and membrane potential propagation in the full and reduced models in NEURON; the reduced model produces identical spiking patterns in NEURON and Virtual Cell. Importantly, our reduced model can simulate communication between the soma and a distal spine; an alpha function applied at the spine to represent synaptic stimulation gave similar results in the full and reduced models for potential changes associated with both the spine and the soma. Finally, we combined

  19. 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

  20. Acute sacroiliitis.

    PubMed

    Slobodin, Gleb; Rimar, Doron; Boulman, Nina; Kaly, Lisa; Rozenbaum, Michael; Rosner, Itzhak; Odeh, Majed

    2016-04-01

    The purpose of this study was to review the data on the etiology, risk factors, clinical presentations, and diagnosis of acute sacroiliitis. A Pubmed search utilizing the indexing term "acute sacroiliitis" was conducted and the data pertinent to the aim of the review was extracted and organized in accordance with the preplanned structure of the manuscript. The diagnosis of acute sacroiliitis is often challenging because of both the relative rarity of this presentation and diverse character of acute sacroiliac pain, frequently mimicking other, more prevalent disorders. Technetium bone scintigraphy can localize the disease process to the sacroiliac joint, while computed tomography or magnetic resonance imaging can be used for the detailed characterization and the extent of the disease as well as the diagnosis of complications. Pyogenic sacroiliitis is by far the most common cause of acute sacroiliitis. Brucellosis, acute sacroiliitis in the course of reactive arthritis, and crystalline-induced sacroiliitis frequently imitate pyogenic sacroiliitis. Acute sacroiliitis can rarely be also related to hematological malignancies or treatment with isotretinoin. Awareness to the possibility of acute sacroiliitis and a thorough physical examination are the necessary prerequisites to its timely diagnosis, while the appropriate laboratory and imaging studies should confirm the precise diagnosis and direct the appropriate treatment strategy. PMID:26847855

  1. Electrophysiologic Assessment of Auditory Training Benefits in Older Adults.

    PubMed

    Anderson, Samira; Jenkins, Kimberly

    2015-11-01

    Older adults often exhibit speech perception deficits in difficult listening environments. At present, hearing aids or cochlear implants are the main options for therapeutic remediation; however, they only address audibility and do not compensate for central processing changes that may accompany aging and hearing loss or declines in cognitive function. It is unknown whether long-term hearing aid or cochlear implant use can restore changes in central encoding of temporal and spectral components of speech or improve cognitive function. Therefore, consideration should be given to auditory/cognitive training that targets auditory processing and cognitive declines, taking advantage of the plastic nature of the central auditory system. The demonstration of treatment efficacy is an important component of any training strategy. Electrophysiologic measures can be used to assess training-related benefits. This article will review the evidence for neuroplasticity in the auditory system and the use of evoked potentials to document treatment efficacy. PMID:27587912

  2. Electrophysiologic studies of the thoracic limb of the horse.

    PubMed

    Blythe, L L; Kitchell, R L

    1982-09-01

    The cutaneous innervation of the thoracic limb was investigated in 18 barbiturate-anesthetized horses, using electrophysiologic techniques. The cutaneous area (CA) innervated by each cutaneous nerve was delineated in at least 4 horses by stroking the hairs with a small watercolor brush while recording from the nerve. Mapping of adjacent CA revealed areas of considerable overlap. The part of a CA of a given nerve supplied only by that nerve is referred to as its autonomous zone (AZ). In contrast to the standard textbook illustrations cutaneous branches of the axillary, radial, musculocutaneous, and ulnar nerves overlapped extensively in the antebrachium. Clinically testable AZ were found in the antebrachium for the caudal cutaneous antebrachial nerve of the ulnar nerve and in the carpus and manus for the cutaneous branches of the median, ulnar, and musculocutaneous nerves; AZ were not found for the cutaneous branches of the radial and axillary nerves. PMID:7149398

  3. The year in review of clinical cardiac electrophysiology.

    PubMed

    Marcus, Gregory M; Keung, Edmund; Scheinman, Melvin M

    2013-02-19

    This past year saw multiple important advances in the field clinical cardiac electrophysiology. Seminal articles describing new anticoagulant drugs for stroke prevention in atrial fibrillation were published. New results that raise questions regarding the safety of dronedarone and several new promising techniques in AF ablation were described. Important articles that refine our understanding of the risk of sudden death among Wolff-Parkinson-White patients were published. In the basic and translational sciences, the application of gene therapy to the study and potential treatment of arrhythmias was described, whereas genetic determinants important to the optimal treatment of inherited arrhythmia syndromes were further elucidated. Issues relevant to cardiac rhythm device therapy included investigations into the St. Jude Riata lead, new applications of device monitoring, predicting response to cardiac resynchronization therapy, and the use of pacemakers for vasovagal syncope. PMID:23312706

  4. Electrophysiological markers of genetic risk for attention deficit hyperactivity disorder

    PubMed Central

    Tye, Charlotte; McLoughlin, Gráinne; Kuntsi, Jonna; Asherson, Philip

    2014-01-01

    Electroencephalography (EEG) is an ideal neuroscientific approach, providing a direct measurement of neural activity that demonstrates reliability, developmental stability and high heritability. This systematic review of a subset of domains evaluates the utility of electrophysiological measures as potential intermediate phenotypes for ADHD in the domains of quantitative EEG indices of arousal and intra-individual variability, and functional investigations of inhibitory and error processing using the event-related potential (ERP) technique. Each domain demonstrates consistent and meaningful associations with ADHD, a degree of genetic overlap with ADHD and potential links to specific genetic variants. Investigations of the genetic and environmental contributions to EEG/ERP and shared genetic overlap with ADHD may enhance molecular genetic studies and provide novel insights into aetiology. Such research will aid in the precise characterisation of the clinical deficits seen in ADHD and guide the development of novel intervention and prevention strategies for those at risk. PMID:21426626

  5. 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. PMID:25218659

  6. Conceptual fluency increases recollection: behavioral and electrophysiological evidence

    PubMed Central

    Wang, Wei; Li, Bingbing; Gao, Chuanji; Xu, Huifang; Guo, Chunyan

    2015-01-01

    It is widely established that fluency can contribute to recognition memory. Previous studies have found that enhanced fluency increases familiarity, but not recollection. The present study was motivated by a previous finding that conceptual priming affected recollection. We used event-related potentials to investigate the electrophysiological correlates of these effects with conceptually related two-character Chinese words. We found that previous conceptual priming effects on conceptual fluency only increased the incidence of recollection responses. We also found that enhanced conceptual fluency was associated with N400 attenuation, which was also correlated with the behavioral indicator of recollection. These results suggest that the N400 effect might be related to the impact of conceptual fluency on recollection recognition. These study findings provide further evidence for the relationship between fluency and recollection. PMID:26175678

  7. Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia

    PubMed Central

    Josephson, Mark E

    2016-01-01

    Atrioventricular nodal reentrant tachycardia (AVNRT) should be classified as typical or atypical. The term ‘fast-slow AVNRT’ is rather misleading. Retrograde atrial activation during tachycardia should not be relied upon as a diagnostic criterion. Both typical and atypical atrioventricular nodal reentrant tachycardia are compatible with varying retrograde atrial activation patterns. Attempts at establishing the presence of a ‘lower common pathway’ are probably of no practical significance. When the diagnosis of AVNRT is established, ablation should be only directed towards the anatomic position of the slow pathway. If right septal attempts are unsuccessful, the left septal side should be tried. Ablation targeting earliest atrial activation sites during typical atrioventricular nodal reentrant tachycardia or the fast pathway in general for any kind of typical or atypical atrioventricular nodal reentrant tachycardia, are not justified. In this review we discuss current concepts about the tachycardia circuit, electrophysiologic diagnosis, and ablation of this arrhythmia.

  8. Photochromic Potassium Channel Blockers: Design and Electrophysiological Characterization

    PubMed Central

    Mourot, Alexandre; Fehrentz, Timm; Kramer, Richard H.

    2016-01-01

    Voltage-gated potassium (Kv) channels are membrane proteins that open a selective pore upon membrane depolarization, allowing K+ ions to flow down their electrochemical gradient. In neurons, Kv channels play a key role in repolarizing the membrane potential during the falling phase of the action potential, often resulting in an after hyperpolarization. Opening of Kv channels results in a decrease of cellular excitability, whereas closing (or pharmacological block) has the opposite effect, increased excitability. We have developed a series of photosensitive blockers for Kv channels that enable reversible, optical regulation of potassium ion flow. Such molecules can be used for remote control of neuronal excitability using light as an on/off switch. Here we describe the design and electrophysiological characterization of photochromic blockers of ion channels. Our focus is on Kv channels but in principle, the techniques described here can be applied to other ion channels and signaling proteins. PMID:23494374

  9. Ataxia telangiectasia in Chinese children. A clinical and electrophysiological study.

    PubMed

    Wong, V; Yu, Y L; Chan-Lui, W Y; Woo, E; Yeung, C Y

    1987-01-01

    The clinical manifestations, immunological, chromosomal, and multimodal electrophysiological studies of five Chinese patients with ataxia telangiectasia are described. One died of hepatocellular carcinoma not associated with Hepatitis B-antigenaemia. Another died of respiratory failure. Two siblings are free of sinopulmonary infections although they are wheelchair bound. Computed tomography of the brain showed cerebellar atrophy in four cases. Nerve conduction studies showed evidence of axonal neuropathy in all cases with the earliest detection at six years. Electromyography showed mild denervation changes in two cases. Two patients had abnormal somatosensory evoked potentials and one had abnormal visual and brain stem auditory evoked potentials. The level of alpha foetal protein was elevated whereas the serum carcino-embryonic antigen was normal in all patients. PMID:3665286

  10. Pitfalls in Using Electrophysiological Studies to Diagnose Neuromuscular Disorders

    PubMed Central

    Koo, Yong Seo; Cho, Charles S.

    2012-01-01

    Electrodiagnostic testing is used widely for the full characterization of neuromuscular disorders and for providing unique information on the processes underlying the pathology of peripheral nerves and muscles. However, such testing should be considered as an extension of anamnesis and physical examination, not as pathognomonic of a specific disease entity. There are many pitfalls that could lead to erroneous interpretation of electrophysiological study results when the studies are not performed properly or if they are performed in the presence of anatomical aberrations. The diagnostic reliability of electrodiagnostic studies can be improved and the associated pitfalls overcome if the physician is familiar with all of those possible pitfalls. In this article we discuss the most common and important pitfalls associated with electrodiagnostic medicine. PMID:22523508

  11. Precise correlation between structural and electrophysiological disturbances in MADSAM neuropathy.

    PubMed

    Simon, Neil G; Kiernan, Matthew C

    2015-11-01

    Multifocal acquired demyelinating sensory and motor neuropathy is characterised by multifocal clinical deficits. Imaging studies have identified multifocal enlargements of nerve trunks, but a precise correlation between structural abnormalities and electrophysiological dysfunction has not been elucidated. Two patients diagnosed with multifocal acquired demyelinating sensory and motor neuropathy were evaluated with nerve conduction studies, including short segment nerve conduction studies to precisely localise motor conduction block, and ultrasound studies of corresponding nerve trunks. Motor conduction block was identified in each patient (upper limb nerves in two patients), superimposed on additional demyelinating neurophysiological features. Upper limb ultrasound studies demonstrated focal nerve enlargement that precisely correlated with neurophysiological conduction block. The results of this study suggest that factors contributing to focal structural abnormalities in multifocal acquired demyelinating sensory and motor neuropathy are also those that produce conduction block. PMID:26314279

  12. Is my voice just a familiar voice? An electrophysiological study

    PubMed Central

    Gomot, Marie; Roux, Sylvie; Bonnet-Brilhault, Frédérique; Bruneau, Nicole

    2015-01-01

    It is not clear whether self-stimuli are processed by the brain as highly familiar overlearned stimuli or as self-specific stimuli. This study examined the neural processes underlying discrimination of one’s own voice (OV) compared with a familiar voice (FV) using electrophysiological methods. Event-related potentials were recorded while healthy subjects (n = 15) listened passively to oddball sequences composed of recordings of the French vowel /a/ pronounced either by the participant her/himself, or by a familiar person or an unknown person. The results indicated that, although mismatch negativity displayed similar peak latency and amplitude in both conditions, the amplitude of the subsequent P3a was significantly smaller in response to OV compared with a FV. This study therefore indicated that fewer pre-attentional processes are involved in the discrimination of one’s OV than in the discrimination of FVs. PMID:24625786

  13. Processing inflectional and derivational morphology: electrophysiological evidence from Spanish.

    PubMed

    Alvarez, Carlos J; Urrutia, Mabel; Domínguez, Alberto; Sánchez-Casas, Rosa

    2011-02-18

    The goal of this paper is to study possible differences between the processing of inflectional vs. derivational morphology in Spanish word recognition using electrophysiological measures. A lexical decision task to target words preceded by morphological-related (or unrelated) primes was used. The orthographic and phonological overlap and the grammatical class for the two experimental conditions were exactly the same. Examples of the related conditions were, for inflection, NIÑO-NIÑA ("girl"-"boy"), and for derivation, RAMO-RAMA ("bunch"-"branch"). These conditions were compared with unrelated pairs without orthographic, phonological or semantic relationships. An attenuation of the N-400 component was found for both related conditions from 300 ms until 450 ms (until 500 ms for inflections only). In addition, different locations were suggested by the source analysis. These findings are consistent with accounts that argue for differences between the processing of inflections and derivations. PMID:21167910

  14. Cardiac electrophysiology in mice: a matter of size

    PubMed Central

    Kaese, Sven; Verheule, Sander

    2012-01-01

    Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias. PMID:22973235

  15. [Electrophysiology principles of Na(+)/HCO3(-) cotransporters].

    PubMed

    Chen, Li-Ming; Liu, Mei; Liu, Ying

    2016-06-25

    Ion channels and transporters represent two major types of pathways of transmembrane transport for ions. Distinct from ion channels which conduct passive ionic diffusion, ion transporters mediate active transport of ions. In the perspective of biochemistry, ion transporters are enzymes that catalyze the movement of ions across the plasma membrane. In the present review, we selected the Na(+)/HCO3(-) cotransporter (NBC) as an example to analyze the key biochemical and biophysical properties of ion transporters, including stoichiometry, turnover number and transport capacity. Moreover, we provided an analysis of the electrophysiological principles of NBC based on the laws of thermodynamics. Based on the thermodynamical analysis, we showed how the stoichiometry of an NBC determines the direction of its ion transport. Finally, we reviewed the methodology for experimental determination of the stoichiometry of NBC, as well as the physiological significance of the stoichiometry of NBCs in specific tissues. PMID:27350205

  16. Microcomputer-based recording system for clinical electrophysiology.

    PubMed

    Török, B

    1990-09-01

    We developed a personal computer-based system for clinical electrophysiologic measurements. The computer interfaced with a commercially available A/D converter, a low-noise isolation preamplifier, filter circuits, pattern and Ganzfeld stimulators, and a hardcopy unit. Separate programs were developed for electroretinography (ERG), pattern ERG and simultaneous visual evoked potential (VEP), flash and pattern-shift VEP, and electro-oculographic measurements. The complete control of the applied hardware (eg, stimulus control, automatic gain, and filter selection) is a common feature of the computer programs. These programs provide oscilloscopic functions, overload protection, artifact elimination, averaging, automatic peak latency and amplitude determination, baseline correction, smoothing, and digital filtering. The results can be presented on matrix, laser printers, or digital plotters. The hardware components and the features of the driver software are demonstrated on normal and pathologic signals. PMID:2276319

  17. [Familial cerebellar ataxia: clinical, radiological and electrophysiological findings].

    PubMed

    Gajkowski, K; Rysz, A; Walecki, J; Bojakowski, J

    1988-01-01

    A family with cerebellar ataxia of late onset occurring in four generations was observed. Neurological abnormalities included signs of cerebellar ataxia, pyramidal tract damage and damage to the peripheral motor neuron. Computerized tomography demonstrated in five out of six studied patients an image suggesting olivo-ponto-cerebellar atrophy. In the cerebellar structures, brainstem and cerebral hemispheres evidence of atrophy was detected. No correlation was demonstrated between the intensity of the clinical signs and the progression of changes in CT image. Electrophysiological investigations demonstrated changes compatible with damage to the motor and sensory fibres in the peripheral nerves and signs suggesting damage to the spinal motor neurons and pyramidal tract. These observations confirm the multilevel development of the process. The use of similar diagnostic methods will permit a more accurate classification of cerebellar ataxia and obtaining of better information for prognostication of individual cases. PMID:3164096

  18. Electrophysiological correlates of cardiac sarcoidosis: an appraisal of current evidence.

    PubMed

    Yadava, Mrinal; Bala, Rupa

    2015-06-01

    Cardiac sarcoidosis is an underdiagnosed condition that may be present in as many as 25% of patients with systemic sarcoidosis. It is associated with significant morbidity and mortality in affected individuals. The presentation of cardiac involvement in sarcoidosis includes sudden death in the absence of preceding symptoms, conduction disturbances, ventricular arrhythmias, and heart failure. A scarcity of randomized data and a lack of prospective trials underlies the contention between experts on the most appropriate strategies for diagnosis and therapy. This review focuses on the electrophysiological sequelae of the disease, with an emphasis on current diagnostic guidelines, multimodality imaging for early detection, and the role of various therapeutic interventions. Multicentre collaboration is necessary to address the numerous unanswered questions pertaining to management of this disease. PMID:26142797

  19. 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

  20. Electrophysiology and metabolism of caveolin-3-overexpressing mice.

    PubMed

    Schilling, Jan M; Horikawa, Yousuke T; Zemljic-Harpf, Alice E; Vincent, Kevin P; Tyan, Leonid; Yu, Judith K; McCulloch, Andrew D; Balijepalli, Ravi C; Patel, Hemal H; Roth, David M

    2016-05-01

    Caveolin-3 (Cav-3) plays a critical role in organizing signaling molecules and ion channels involved in cardiac conduction and metabolism. Mutations in Cav-3 are implicated in cardiac conduction abnormalities and myopathies. Additionally, cardiac-specific overexpression of Cav-3 (Cav-3 OE) is protective against ischemic and hypertensive injury, suggesting a potential role for Cav-3 in basal cardiac electrophysiology and metabolism involved in stress adaptation. We hypothesized that overexpression of Cav-3 may alter baseline cardiac conduction and metabolism. We examined: (1) ECG telemetry recordings at baseline and during pharmacological interventions, (2) ion channels involved in cardiac conduction with immunoblotting and computational modeling, and (3) baseline metabolism in Cav-3 OE and transgene-negative littermate control mice. Cav-3 OE mice had decreased heart rates, prolonged PR intervals, and shortened QTc intervals with no difference in activity compared to control mice. Dobutamine or propranolol did not cause significant changes between experimental groups in maximal (dobutamine) or minimal (propranolol) heart rate. Cav-3 OE mice had an overall lower chronotropic response to atropine. The expression of Kv1.4 and Kv4.3 channels, Nav1.5 channels, and connexin 43 were increased in Cav-3 OE mice. A computational model integrating the immunoblotting results indicated shortened action potential duration in Cav-3 OE mice linking the change in channel expression to the observed electrophysiology phenotype. Metabolic profiling showed no gross differences in VO2, VCO2, respiratory exchange ratio, heat generation, and feeding or drinking. In conclusion, Cav-3 OE mice have changes in ECG intervals, heart rates, and cardiac ion channel expression. These findings give novel mechanistic insights into previously reported Cav-3 dependent cardioprotection. PMID:27023865

  1. Central vs. peripheral neuraxial sympathetic control of porcine ventricular electrophysiology.

    PubMed

    Yamakawa, Kentaro; Howard-Quijano, Kimberly; Zhou, Wei; Rajendran, Pradeep; Yagishita, Daigo; Vaseghi, Marmar; Ajijola, Olujimi A; Armour, J Andrew; Shivkumar, Kalyanam; Ardell, Jeffrey L; Mahajan, Aman

    2016-03-01

    Sympathoexcitation is associated with ventricular arrhythmogenesis. The aim of this study was to determine the role of thoracic dorsal root afferent neural inputs to the spinal cord in modulating ventricular sympathetic control of normal heart electrophysiology. We hypothesize that dorsal root afferent input tonically modulates basal and evoked efferent sympathetic control of the heart. A 56-electrode sock placed on the epicardial ventricle in anesthetized Yorkshire pigs (n = 17) recorded electrophysiological function, as well as activation recovery interval (ARI) and dispersion in ARI, at baseline conditions and during stellate ganglion electrical stimulation. Measures were compared between intact states and sequential unilateral T1-T4 dorsal root transection (DRTx), ipsilateral ventral root transection (VRTx), and contralateral dorsal and ventral root transections (DVRTx). Left or right DRTx decreased global basal ARI [Lt.DRTx: 369 ± 12 to 319 ± 13 ms (P < 0.01) and Rt.DRTx: 388 ± 19 to 356 ± 15 ms (P < 0.01)]. Subsequent unilateral VRTx followed by contralateral DRx+VRTx induced no further change. In intact states, left and right stellate ganglion stimulation shortened ARIs (6 ± 2% vs. 17 ± 3%), while increasing dispersion (+139% vs. +88%). There was no difference in magnitude of ARI or dispersion change with stellate stimulation following spinal root transections. Interruption of thoracic spinal afferent signaling results in enhanced basal cardiac sympathoexcitability without diminishing the sympathetic response to stellate ganglion stimulation. This suggests spinal dorsal root transection releases spinal cord-mediated tonic inhibitory control of efferent sympathetic tone, while maintaining intrathoracic cardiocentric neural networks. PMID:26661096

  2. Correlation between muscle electrophysiology and strength after fibular nerve injury.

    PubMed

    Won, Yu Hui; Kim, Kang-Won; Choi, Jun Tak; Ko, Myoung-Hwan; Park, Sung-Hee; Seo, Jeong-Hwan

    2016-08-01

    Muscle strength measurement is important when evaluating the degree of impairment in patients with nerve injury. However, accurate and objective evaluation may be difficult in patients with severe pain or those who intentionally try to avoid full exertion. We investigated the usefulness of the affected-to-unaffected side electrophysiological parameter ratios as a measure of objective ankle dorsiflexion (ADF) strength in patients with unilateral fibular nerve injury (FNI). ADF strength was measured in patients with FNI via handheld dynamometer and manual muscle test (MMT). Fibular nerve compound muscle action potential (CMAP) amplitude and latency and ADF strength of the affected side were presented as ratios to the corresponding measurements of the unaffected side. We analysed the correlation of the CMAP ratio with the ADF strength ratio using a dynamometer and compared the CMAP ratios according to MMT grade. Fifty-two patients with FNI were enrolled. The mean CMAP latency ratio did not differ between MMT groups (p = 0.573). The CMAP amplitude ratio proportionally increased with the quantified ADF strength ratio via dynamometer increase (ρ = 0.790; p < 0.001), but the CMAP latency ratio and the quantified ADF strength ratio did not significantly correlate (ρ = 0.052; p = 0.713). The average CMAP amplitude ratio significantly differed between MMT groups (p < 0.001), and post hoc tests showed significant differences in all paired comparisons except of Fair and Good grades (p = 0.064). Electrophysiological parameter ratio, such as the affected-to-unaffected side CMAP amplitude ratio, might be sensitive parameters for ADF power estimation after FNI. PMID:27142447

  3. Acute malocclusion.

    PubMed

    Dupont, John S

    2006-01-01

    Acute malocclusion can result from disturbances in the maxillary/mandibular tooth relationship. These alterations in the occlusal position can result from high fillings, sinus problems, abscesses, periodontal disease, and moving or erupting teeth. Conditions seen less frequently include acute malocclusions secondary to an event (such as trauma) that make a stable dental relationship an unstable one. Patients can demonstrate any of a number of clinical conditions that interfere with their comfort and ability to function. This article provides information on some of the less familiar causes of acute malocclusion. PMID:16689064

  4. 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

  5. Pre-hospital diagnosis and transfer of patients with acute myocardial infarction--a decade long experience from one of Europe's largest STEMI networks.

    PubMed

    Clemmensen, Peter; Schoos, Mikkel Malby; Lindholm, Matias Greve; Rasmussen, Lars S; Steinmetz, Jacob; Hesselfeldt, Rasmus; Pedersen, Frants; Jørgensen, Erik; Holmvang, Lene; Sejersten, Maria

    2013-01-01

    Early reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) is essential. Although primary percutaneous coronary intervention (pPCI) is the preferred revascularization technique, it often involves longer primary transportation or secondary inter-hospital transfers and thus longer system related delays. The current ESC Guidelines state that PCI should be performed within 120 minutes from first medical contact, and door-to-balloon time should be <60 minutes in order to reduce long term mortality. STEMI networks should be established with regionalization of pPCI treatment to address the challenges regarding pre-hospital treatment, triage and transport of STEMI patients and collaborations between hospitals and Emergency Medical Services (EMS). We report on a regional decade long experience from one of Europe's largest STEMI networks located in Eastern Denmark, which serves a catchment area of 2.5 million inhabitants by processing ~4000 prehospital ECGs annually transmitted from 4 EMS systems to a single pPCI center treating 1100 patients per year. This organization has led to a significant improvement of the standard of therapy for acute myocardial infarction (MI) patients leading to historically low 30-day mortality for STEMI patients (<6%). About 70-80% of all STEMI patients are being triaged from the field and rerouted to the regional pPCI center. Significant delays are still found among patients who present to local hospitals and for those who are first admitted to a local emergency room and thus subject to inter-hospital transfer. In the directly transferred group, approximately 80% of patients can be treated within the current guideline time window of 120 minutes when triaged within a 185 km (~115 miles) radius. Since 2010, a Helicopter Emergency Medical Service has been implemented for air rescue. Air transfer was associated with a 20-30 minute decrease from first medical contact to pPCI, at distances down to 90 km from the pPCI center

  6. Comparison of two electrophysiological methods for the assessment of progress in a rat model of nerve repair.

    PubMed

    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

  7. An experience with plasma exchange treatment of acute lymphoblastic leukemia in a case with fulminant hepatitis related to L-asparaginase.

    PubMed

    Bilgir, Oktay; Calan, Mehmet; Bilgir, Ferda; Cagliyan, Gulsum; Arslan, Oyku

    2013-10-01

    Acute lymphoblastic leukemia (ALL) is a malignant disorder resulting from the clonal proliferation of lymphoid precursors with arrested maturation. L-asparaginase is commonly used in combination chemotherapy of both pediatric and adult acute lymphoblastic leukemias. The most commonly encountered side effects of L-asparaginase are hypersensitivity reactions like pyrexia, urticaria, skin rash, and respiratory distress. There are also other side effects like anaphylaxis, coagulopathy, pancreatitis, thrombosis, and hepatic toxicity. Plasmapheresis can sometimes be appropriate to manage an overdose of drugs that circulate in the plasma compartment. We have reported plasmapheresis treatment of fulminant hepatitis in a patient with ALL after L-asparaginase treatment. PMID:23871581

  8. 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

  9. Acute Bronchitis

    MedlinePlus

    ... bronchitis? Acute bronchitis is almost always caused by viruses that attack the lining of the bronchial tree ... infection. As your body fights back against these viruses, more swelling occurs and more mucus is produced. ...

  10. Acute Pericarditis

    MedlinePlus

    ... large pericardial effusions). Acute pericarditis usually responds to colchicine or NSAIDs (such as aspirin and ibuprofen ) taken ... reduce pain but relieves it by reducing inflammation. Colchicine also decreases the chance of pericarditis returning later. ...

  11. 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

  12. 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

  13. 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

  14. Differences in Left Versus Right Ventricular Electrophysiological Properties in Cardiac Dysfunction and Arrhythmogenesis

    PubMed Central

    Molina, Cristina E; Heijman, Jordi; Dobrev, Dobromir

    2016-01-01

    A wide range of ion channels, transporters, signaling pathways and tissue structure at a microscopic and macroscopic scale regulate the electrophysiological activity of the heart. Each region of the heart has optimised these properties based on its specific role during the cardiac cycle, leading to well-established differences in electrophysiology, Ca2+ handling and tissue structure between atria and ventricles and between different layers of the ventricular wall. Similarly, the right ventricle (RV) and left ventricle (LV) have different embryological, structural, metabolic and electrophysiological features, but whether interventricular differences promote differential remodeling leading to arrhythmias is not well understood. In this article, we will summarise the available data on intrinsic differences between LV and RV electrophysiology and indicate how these differences affect cardiac function. Furthermore, we will discuss the differential remodeling of both chambers in pathological conditions and its potential impact on arrhythmogenesis. PMID:27403288

  15. Electrophysiological evidence for rapid 5-HT₁A autoreceptor inhibition by vilazodone, a 5-HT₁A receptor partial agonist and 5-HT reuptake inhibitor.

    PubMed

    Ashby, Charles R; Kehne, John H; Bartoszyk, Gerd D; Renda, Matthew J; Athanasiou, Maria; Pierz, Kerri A; Seyfried, Christoph A

    2013-08-15

    This study examined the effect of vilazodone, a combined serotonin (5-HT) reuptake inhibitor and 5-HT(1A) receptor partial agonist, paroxetine and fluoxetine on the sensitivity of 5-HT(1A) autoreceptors of serotonergic dorsal raphe nucleus neurons in rats. These effects were assessed by determining the intravenous dose of (±)-8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) required to suppress the basal firing rate of these neurons by 50% (ID₅₀) in anesthetized rats using in vivo electrophysiology. 5-HT uptake inhibition was determined by the ability of the compounds to reverse (±)-p-chloroamphetamine (PCA)-induced rat hypothalamic 5-HT depletion ex vivo. Acute vilazodone administration (0.63 and 2.1 µmol/kg, s.c.), compared with vehicle, significantly increased (2-3-fold) the ID₅₀ of 8-OH-DPAT at 4 h, but not 24h after administration. Subchronic administration (3 days) significantly increased the ID₅₀ value at 4 h (3-4-fold) and at 24 h (~2-fold). In contrast, paroxetine and fluoxetine at doses that were supramaximal for 5-HT uptake inhibition did not significantly alter the ID₅₀ value of 8-OH-DPAT after acute or subchronic administration. Vilazodone antagonized the action of PCA 3.5 h and 5 h after a single dose (ID₅₀ 1.49 and 0.46 µmol/kg, s.c., respectively), but was inactive 18 h post-administration, corroborating the electrophysiological results at 24 h following acute administration. The results are consistent with the concept of rapid and, following repeated treatment, prolonged inhibition of 5-HT(1A) autoreceptors by vilazodone. This effect could occur by either direct interaction with, or desensitization of, these receptors, an effect which cannot be ascribed to vilazodone's 5-HT reuptake inhibiting properties. PMID:23872377

  16. Electrophysiological characterisation of motor and sensory tracts in patients with hereditary spastic paraplegia (HSP)

    PubMed Central

    2013-01-01

    Background Hereditary spastic paraplegias (HSPs) are characterised by lower limb spasticity due to degeneration of the corticospinal tract. We set out for an electrophysiological characterisation of motor and sensory tracts in patients with HSP. Methods We clinically and electrophysiologically examined a cohort of 128 patients with genetically confirmed or clinically probable HSP. Motor evoked potentials (MEPs) to arms and legs, somato-sensory evoked potentials of median and tibial nerves, and nerve conduction studies of tibial, ulnar, sural, and radial nerves were assessed. Results Whereas all patients showed clinical signs of spastic paraparesis, MEPs were normal in 27% of patients and revealed a broad spectrum with axonal or demyelinating features in the others. This heterogeneity can at least in part be explained by different underlying genotypes, hinting for distinct pathomechanisms in HSP subtypes. In the largest subgroup, SPG4, an axonal type of damage was evident. Comprehensive electrophysiological testing disclosed a more widespread affection of long fibre tracts involving peripheral nerves and the sensory system in 40%, respectively. Electrophysiological abnormalities correlated with the severity of clinical symptoms. Conclusions Whereas HSP is primarily considered as an upper motoneuron disorder, our data suggest a more widespread affection of motor and sensory tracts in the central and peripheral nervous system as a common finding in HSP. The distribution patterns of electrophysiological abnormalities were associated with distinct HSP genotypes and could reflect different underlying pathomechanisms. Electrophysiological measures are independent of symptomatic treatment and may therefore serve as a reliable biomarker in upcoming HSP trials. PMID:24107482

  17. Modelling tissue electrophysiology with multiple cell types: applications of the extended bidomain framework.

    PubMed

    Corrias, Alberto; Pathmanathan, Pras; Gavaghan, David J; Buist, Martin L

    2012-02-01

    The bidomain framework has been extensively used to model tissue electrophysiology in a variety of applications. One limitation of the bidomain model is that it describes the activity of only one cell type interacting with the extracellular space. If more than one cell type contributes to the tissue electrophysiology, then the bidomain model is not sufficient. Recently, evidence has suggested that this is the case for at least two important applications: cardiac and gastrointestinal tissue electrophysiology. In the heart, fibroblasts ubiquitously interact with myocytes and are believed to play an important role in the organ electrophysiology. Along the GI tract, interstitial cells of Cajal (ICC) generate electrical waves that are passed on to surrounding smooth muscle cells (SMC), which are interconnected with the ICC and with each other. Because of the contribution of more than one cell type to the overall organ electrophysiology, investigators in different fields have independently proposed similar extensions of the bidomain model to incorporate multiple cell types and tested it on simplified geometries. In this paper, we provide a general derivation of such an extended bidomain framework applicable to any tissue and provide a generic and efficient implementation applicable to any geometry. Proof-of-concept results of tissue electrophysiology on realistic 3D organ geometries using the extended bidomain framework are presented for the heart and the stomach. PMID:22222297

  18. Multifocal motor neuropathy: correlation of nerve ultrasound, electrophysiological, and clinical findings.

    PubMed

    Kerasnoudis, Antonios; Pitarokoili, Kalliopi; Behrendt, Volker; Gold, Ralf; Yoon, Min-Suk

    2014-06-01

    We present nerve ultrasound findings in multifocal motor neuropathy (MMN) and examine their correlation with electrophysiology and functional disability. Eighty healthy controls and 12 MMN patients underwent clinical, sonographic, and electrophysiological evaluation a mean of 3.5 years (standard deviation [SD] ± 2.1) after disease onset. Nerve ultrasound revealed significantly higher cross-sectional area (CSA) values of the median (forearm, p < 0.001), ulnar (p < 0.001), and tibial nerve (ankle, p < 0.001) when compared with controls. Electroneurography documented signs of significantly lower values of the motor conduction velocity and compound muscle action potentials (cMAPs) in the upper arm nerves (median, ulnar, radial, p < 0.001). A significant correlation between sonographic and electrophysiological findings in the MMN group was found only between cMAP and CSA of the median nerve at the upper arm (r = 0.851, p < 0.001). Neither nerve sonography nor electrophysiology correlated with functional disability. MMN seems to show inhomogeneous CSA enlargement in various peripheral nerves, with weak correlation to electrophysiological findings. Neither nerve sonography nor electrophysiology correlated with functional disability. Multicentre, prospective studies are required to prove the applicability and diagnostic values of these findings. PMID:24862982

  19. Acute myelogenous leukemia (AML) - children

    MedlinePlus

    Acute myelogenous leukemia - children; AML; Acute myeloid leukemia - children; Acute granulocytic leukemia - children; Acute myeloblastic leukemia - children; Acute non-lymphocytic leukemia (ANLL) - children

  20. Distinct morphological and electrophysiological properties of an elk prion peptide.

    PubMed

    Glaves, John Paul; Gorski, Przemek A; Alier, Kwai; Ma, Li; Renault, Ludovic; Primeau, Joseph O; Jhamandas, Jack H; Young, Howard S

    2013-02-01

    A key event in prion diseases is the conversion of the prion protein (PrP) from its native α-helical conformation to a misfolded, β-sheet rich conformation. Thus, preventing or reversing PrP misfolding could provide a means to disrupt prion disease progression and transmission. However, determining the structure of misfolded PrP has been notoriously difficult due to its inherent heterogeneity and aggregation behavior. For these reasons, simplified peptide fragments have been used as models that recapitulate characteristics of full-length PrP, such as amyloid-like aggregation and fibril formation, and in vitro toxicity. We provide a biochemical and structural comparison of PrP(127-147) peptides from elk, bovine and hamster using electrophysiology, electron microscopy and fluorescence. Our results demonstrate that the PrP(127-147) peptides adopt distinct populations of fibril structures. In addition, the elk PrP(127-147) peptide is unique in its ability to enhance Thioflavin T fluorescence and its ability to modulate neuronal ion channel conductances. PMID:23262353

  1. Electrophysiological action of bepridil on atrioventricular accessory pathways.

    PubMed Central

    Touboul, P; Atallah, G; Kirkorian, G; Lavaud, P; Kieny, J R; Mathieu, M P; Dellinger, A

    1987-01-01

    The electrophysiologic properties of bepridil, a calcium channel blocker with additional effects on fast response tissues, were investigated in 10 patients with atrioventricular accessory pathways. Seven patients had Wolff-Parkinson-White syndrome, and three had concealed atrioventricular pre-excitation. A dose of 4 mg/kg was administered intravenously over five minutes. Bepridil increased the AH interval and the functional refractory period of the atrioventricular node. The effective refractory periods of the right atrium and right ventricle were also increased. Bepridil prolonged refractoriness in the accessory pathway both in the anterograde and retrograde direction. After bepridil administration it was impossible to induce reciprocating tachycardia electrically in two patients because of conduction block in the normal pathway. On the other hand, the zone of tachycardia was often increased after bepridil. Nevertheless, the heart rate during tachycardia was slowed by depression of conduction in both the normal and accessory pathways. The findings of this study provide a basis for the antiarrhythmic action of bepridil in patients with atrioventricular accessory pathways. PMID:3499924

  2. 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

  3. An empirical reevaluation of absolute pitch: behavioral and electrophysiological measurements.

    PubMed

    Elmer, Stefan; Sollberger, Silja; Meyer, Martin; Jäncke, Lutz

    2013-10-01

    Here, we reevaluated the "two-component" model of absolute pitch (AP) by combining behavioral and electrophysiological measurements. This specific model postulates that AP is driven by a perceptual encoding ability (i.e., pitch memory) plus an associative memory component (i.e., pitch labeling). To test these predictions, during EEG measurements AP and non-AP (NAP) musicians were passively exposed to piano tones (first component of the model) and additionally instructed to judge whether combinations of tones and labels were conceptually associated or not (second component of the model). Auditory-evoked N1/P2 potentials did not reveal differences between the two groups, thus indicating that AP is not necessarily driven by a differential pitch encoding ability at the processing level of the auditory cortex. Otherwise, AP musicians performed the conceptual association task with an order of magnitude better accuracy and shorter RTs than NAP musicians did, this result clearly pointing to distinctive conceptual associations in AP possessors. Most notably, this behavioral superiority was reflected by an increased N400 effect and accompanied by a subsequent late positive component, the latter not being distinguishable in NAP musicians. PMID:23647515

  4. Electrophysiological assessment of corticorespiratory pathway function in amyotrophic lateral sclerosis.

    PubMed

    Shimizu, Toshio; Komori, Tetsuo; Kugio, Yumiko; Fujimaki, Yumi; Oyanagi, Kiyomitsu; Hayashi, Hideaki

    2010-01-01

    Respiratory muscle paralysis is inevitable in the clinical course of amyotrophic lateral sclerosis (ALS). Our objective was to electrophysiologically assess the function of the phrenic nerve and diaphragm motor cortex in ALS. Phrenic nerve M waves, diaphragm motor evoked potentials (MEPs) induced by transcranial magnetic stimulation, and their clinical correlations were analyzed in 29 ALS patients. The M wave amplitude was significantly lower in patients than in healthy control subjects (p<0.001). The MEP amplitudes both in the expiratory and inspiratory phases were significantly decreased in patients (p<0.01). In particular, 15 patients showed no MEPs in the expiratory phase, six of whom also showed no MEPs in the inspiratory phase. Five of them had no respiratory complaints. There was a weak, non-significant correlation between the inspiratory MEP amplitude and forced vital capacity (p=0.052). We conclude that the loss of MEP might reflect the subclinical involvement of the voluntary respiratory drive from the diaphragm motor cortex, potentially leading to further respiratory deterioration. PMID:19707909

  5. 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

  6. 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

  7. 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

  8. Differential Electrophysiological Responses to Odorant Isotopologues in Drosophilid Antennae.

    PubMed

    Drimyli, Efstathia; Gaitanidis, Alexandros; Maniati, Klio; Turin, Luca; Skoulakis, Efthimios M C

    2016-01-01

    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

  9. Application of Parallel Factor Analysis (PARAFAC) to electrophysiological data

    PubMed Central

    Schmitz, S. Katharina; Hasselbach, Philipp P.; Ebisch, Boris; Klein, Anja; Pipa, Gordon; Galuske, Ralf A. W.

    2015-01-01

    The identification of important features in multi-electrode recordings requires the decomposition of data in order to disclose relevant features and to offer a clear graphical representation. This can be a demanding task. Parallel Factor Analysis (PARAFAC; Hitchcock, 1927; Carrol and Chang, 1970; Harshman, 1970) is a method to decompose multi-dimensional arrays in order to focus on the features of interest, and provides a distinct illustration of the results. We applied PARAFAC to analyse spatio-temporal patterns in the functional connectivity between neurons, as revealed in their spike trains recorded in cat primary visual cortex (area 18). During these recordings we reversibly deactivated feedback connections from higher visual areas in the pMS (posterior middle suprasylvian) cortex in order to study the impact of these top-down signals. Cross correlation was computed for every possible pair of the 16 electrodes in the electrode array. PARAFAC was then used to reveal the effects of time, stimulus, and deactivation condition on the correlation patterns. Our results show that PARAFAC is able to reliably extract changes in correlation strength for different experimental conditions and display the relevant features. Thus, PARAFAC proves to be well-suited for the use in the context of electrophysiological (action potential) recordings. PMID:25688205

  10. Towards predictive modelling of the electrophysiology of the heart

    PubMed Central

    Vigmond, Edward; Vadakkumpadan, Fijoy; Gurev, Viatcheslav; Arevalo, Hermenegild; Deo, Makarand; Plank, Gernot; Trayanova, Natalia

    2010-01-01

    The simulation of cardiac electrical function is an example of a successful integrative multiscale modelling approach that is directly relevant to human disease. Today we stand at the threshold of a new era, in which anatomically detailed, tomographically reconstructed models are being developed that integrate from the ion channel to the electromechanical interactions in the intact heart. Such models hold high promise for interpretation of clinical and physiological measurements, for improving the basic understanding of the mechanisms of dysfunction in disease, such as arrhythmias, myocardial ischaemia and heart failure, and for the development and performance optimization of medical devices. The goal of this article is to present an overview of current state-of-art advances towards predictive computational modelling of the heart as developed recently by the authors of this article. We first outline the methodology for constructing electrophysiological models of the heart. We then provide three examples that demonstrate the use of these models, focusing specifically on the mechanisms for arrhythmogenesis and defibrillation in the heart. These include: (1) uncovering the role of ventricular structure in defibrillation; (2) examining the contribution of Purkinje fibres to the failure of the shock; and (3) using magnetic resonance imaging reconstructed heart models to investigate the re-entrant circuits formed in the presence of an infarct scar. PMID:19270037

  11. 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

  12. Spectrally resolved fast transient brain states in electrophysiological data.

    PubMed

    Vidaurre, Diego; Quinn, Andrew J; Baker, Adam P; Dupret, David; Tejero-Cantero, Alvaro; Woolrich, Mark W

    2016-02-01

    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

  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. Electrophysiology of human cardiac atrial and ventricular telocytes.

    PubMed

    Sheng, Jingwei; Shim, Winston; Lu, Jun; Lim, Sze Yun; Ong, Boon Hean; Lim, Tien Siang; Liew, Reginald; Chua, Yeow Leng; Wong, Philip

    2014-02-01

    Telocytes (TCs) with exceptionally long cellular processes of telopodes have been described in human epicardium to act as structural supporting cells in the heart. We examined myocardial chamber-specific TCs identified in atrial and ventricular fibroblast culture using immunocytochemistry and studied their electrophysiological property by whole-cell patch clamp. Atrial and ventricular TCs with extended telopodes and alternating podoms and podomers that expressed CD34, c-Kit and PDGFR-β were identified. These cells expressed large conductance Ca²⁺-activated K⁺ current (BK(Ca)) and inwardly rectifying K⁺ current (IK(ir)), but not transient outward K⁺ current (I(to)) and ATP-sensitive potassium current (K(ATP)). The active channels were functionally competent with demonstrated modulatory response to H2 S and transforming growth factor (TGF)-β1 whereby H₂S significantly inhibited the stimulatory effect of TGF-β1 on current density of both BKCa and IK(ir). Furthermore, H₂S attenuated TGF-β1-stimulated KCa1.1/Kv1.1 (encode BK(Ca)) and Kir2.1 (encode IK(ir)) expression in TCs. Our results show that functionally competent K⁺ channels are present in human atrial and ventricular TCs and their modulation may have significant implications in myocardial physiopathology. PMID:24467431

  15. 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

  16. Myokit: A simple interface to cardiac cellular electrophysiology.

    PubMed

    Clerx, Michael; Collins, Pieter; de Lange, Enno; Volders, Paul G A

    2016-01-01

    Myokit is a new powerful and versatile software tool for modeling and simulation of cardiac cellular electrophysiology. Myokit consists of an easy-to-read modeling language, a graphical user interface, single and multi-cell simulation engines and a library of advanced analysis tools accessible through a Python interface. Models can be loaded from Myokit's native file format or imported from CellML. Model export is provided to C, MATLAB, CellML, CUDA and OpenCL. Patch-clamp data can be imported and used to estimate model parameters. In this paper, we review existing tools to simulate the cardiac cellular action potential to find that current tools do not cater specifically to model development and that there is a gap between easy-to-use but limited software and powerful tools that require strong programming skills from their users. We then describe Myokit's capabilities, focusing on its model description language, simulation engines and import/export facilities in detail. Using three examples, we show how Myokit can be used for clinically relevant investigations, multi-model testing and parameter estimation in Markov models, all with minimal programming effort from the user. This way, Myokit bridges a gap between performance, versatility and user-friendliness. PMID:26721671

  17. 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

  18. Electrophysiological correlates of morphological processing in Chinese compound word recognition

    PubMed Central

    Du, Yingchun; Hu, Weiping; Fang, Zhuo; Zhang, John X.

    2013-01-01

    The present study investigated the electrophysiological correlates of morphological processing in Chinese compound word reading using a delayed repetition priming paradigm. Participants were asked to passively view lists of two-character compound words containing prime-target pairs separated by a few items. In a Whole Word repetition condition, the prime and target were the same real words (e.g., , manager-manager). In a Constituent repetition condition, the prime and target were swapped in terms of their constituent position (e.g., , the former is a pseudo-word and the later means nurse). Two ERP components including N200 and N400 showed repetition effects. The N200 showed a negative shift upon repetition in the Whole Word condition but this effect was delayed for the Constituent condition. The N400 showed comparable amplitude reduction across the two priming conditions. The results reveal different aspects of morphological processing with an early stage associated with N200 and a late stage with N400. There was also a possibility that the N200 effect reflect general cognitive processing, i.e., the detection of low-probability stimuli. PMID:24068994

  19. 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.

  20. Intending to forget is not easy: Behavioral and electrophysiological evidence.

    PubMed

    Gao, Heming; Cao, Bihua; Zhang, Qi; Qi, Mingming; Li, Fuhong; Li, Hong

    2016-06-01

    Previous researches have shown that recognition accuracy is lower for items cued to-be-forgotten (TBF) than to-be-remembered (TBR). Does directed forgetting help people forget more items than non-directed forgetting? Here, we modified the directed forgetting paradigm by adding a non-cue condition (NC). Consequently, non-directed forgetting would occur in NC. Behavioral results showed higher recognition accuracy for TBF than NC items, indicating that directed forgetting is less effective than non-directed forgetting. Electrophysiological results indicated that: (1) Remembered TBF items evoke an increased late positive component (LPC) than remembered NC items; (2) compared with remembered NC items, remembered TBF items showed a pronounced left-lateralized old/new effect and a reduced right-lateralized reversed old/new effect; (3) a right-lateralized reversed old/new effect was observed for forgotten TBF, but it was absent for forgotten NC items. These results demonstrate that the TBF items have a greater memory trace than the NC items. Forgetting cue has little effect of forgetting item from memory, and it might prompt subject to process or at least focus attention on the TBF items. PMID:27021846

  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. 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. PMID:19673825

  3. Automatically Generated, Anatomically Accurate Meshes for Cardiac Electrophysiology Problems

    PubMed Central

    Prassl, Anton J.; Kickinger, Ferdinand; Ahammer, Helmut; Grau, Vicente; Schneider, Jürgen E.; Hofer, Ernst; Vigmond, Edward J.; Trayanova, Natalia A.

    2010-01-01

    Significant advancements in imaging technology and the dramatic increase in computer power over the last few years broke the ground for the construction of anatomically realistic models of the heart at an unprecedented level of detail. To effectively make use of high-resolution imaging datasets for modeling purposes, the imaged objects have to be discretized. This procedure is trivial for structured grids. However, to develop generally applicable heart models, unstructured grids are much preferable. In this study, a novel image-based unstructured mesh generation technique is proposed. It uses the dual mesh of an octree applied directly to segmented 3-D image stacks. The method produces conformal, boundary-fitted, and hexahedra-dominant meshes. The algorithm operates fully automatically with no requirements for interactivity and generates accurate volume-preserving representations of arbitrarily complex geometries with smooth surfaces. The method is very well suited for cardiac electrophysiological simulations. In the myocardium, the algorithm minimizes variations in element size, whereas in the surrounding medium, the element size is grown larger with the distance to the myocardial surfaces to reduce the computational burden. The numerical feasibility of the approach is demonstrated by discretizing and solving the monodomain and bidomain equations on the generated grids for two preparations of high experimental relevance, a left ventricular wedge preparation, and a papillary muscle. PMID:19203877

  4. 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. PMID:24892726

  5. 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

  6. Acute Motor Axonal Neuropathy (Aman) With Motor Conduction Blocks In Childhood; Case Report.

    PubMed

    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

  7. Electrophysiological evidence for the role of shared space in online comprehension of spatial demonstratives.

    PubMed

    Peeters, David; Hagoort, Peter; Özyürek, Aslı

    2015-03-01

    A fundamental property of language is that it can be used to refer to entities in the extra-linguistic physical context of a conversation in order to establish a joint focus of attention on a referent. Typological and psycholinguistic work across a wide range of languages has put forward at least two different theoretical views on demonstrative reference. Here we contrasted and tested these two accounts by investigating the electrophysiological brain activity underlying the construction of indexical meaning in comprehension. In two EEG experiments, participants watched pictures of a speaker who referred to one of two objects using speech and an index-finger pointing gesture. In contrast with separately collected native speakers' linguistic intuitions, N400 effects showed a preference for a proximal demonstrative when speaker and addressee were in a face-to-face orientation and all possible referents were located in the shared space between them, irrespective of the physical proximity of the referent to the speaker. These findings reject egocentric proximity-based accounts of demonstrative reference, support a sociocentric approach to deixis, suggest that interlocutors construe a shared space during conversation, and imply that the psychological proximity of a referent may be more important than its physical proximity. PMID:25490130

  8. Sevoflurane improves electrophysiological recovery of rat hippocampal slice CA1 pyramidal neurons after hypoxia.

    PubMed

    Matei, Gina; Pavlik, Rostislav; McCadden, Tai; Cottrell, James E; Kass, Ira S

    2002-10-01

    Sevoflurane is a volatile anesthetic agent that reduces cerebral metabolism and thereby may reduce neuronal damage during energy deprivation. We have examined the effect of sevoflurane on hypoxic neuronal damage in rat hippocampal slices. Slices were subjected to 0%, 2%, or 4% sevoflurane 10 minutes before, during, and 10 minutes after hypoxia. The Schaffer collateral pathway was stimulated every 10 seconds and the evoked population spike recorded in the CA1 pyramidal cell region throughout the experiment. During hypoxia, the postsynaptic evoked response was blocked. The time until the blockade of this response in the 0% sevoflurane group was 158 seconds. Sevoflurane (4%) significantly delayed the loss of the evoked response during hypoxia (242 seconds). The percent recovery of the postsynaptic population spike was calculated by dividing the size of the response 120 minutes after hypoxia by its prehypoxic, presevoflurane amplitude. There was no recovery of the population spike in the 0% sevoflurane group 120 minutes after the end of 5 minutes of hypoxia (6 +/- 6%); there was significantly better recovery after 5 minutes of hypoxia in the sevoflurane (4%) treated group (40 +/- 9%). A lower concentration of sevoflurane (2%) delayed the loss of evoked response during hypoxia (191 seconds), but it did not significantly affect recovery of the population spike after hypoxia (7 +/- 7%). Hypoxia irreversibly damages electrophysiologic activity. A high, but clinically usable, concentration of sevoflurane increases the time during hypoxia until the postsynaptic evoked response is blocked and improves recovery of this response after 5 minutes of hypoxia. PMID:12357086

  9. 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

  10. 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.

  11. 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

  12. Swapping or dropping? Electrophysiological measures of difficulty during multiple object tracking.

    PubMed

    Drew, Trafton; Horowitz, Todd S; Vogel, Edward K

    2013-02-01

    In the multiple object tracking task, participants are asked to keep targets separate from identical distractors as all items move randomly. It is well known that simple manipulations such as object speed and number of distractors dramatically alter the number of targets that are successfully tracked, but very little is known about what causes this variation in performance. One possibility is that participants tend to lose track of objects (dropping) more frequently under these conditions. Another is that the tendency to confuse a target with a distractor increases (swapping). These two mechanisms have very different implications for the attentional architecture underlying tracking. However, behavioral data alone cannot differentiate between these possibilities. In the current study, we used an electrophysiological marker of the number of items being actively tracked to assess which type of errors tended to occur during speed and distractor load manipulations. Our neural measures suggest that increased distractor load led to an increased likelihood of confusing targets with distractors while increased speed led to an increased chance of a target item being dropped. Behavioral experiments designed to test this novel prediction support this assertion. PMID:23141025

  13. Electrophysiological differentiation of phonological and semantic integration in word and sentence contexts

    PubMed Central

    Diaz, Michele T.; Swaab, Tamara Y.

    2006-01-01

    During auditory language comprehension, listeners need to rapidly extract meaning from the continuous speech-stream. It is a matter of debate when and how contextual information constrains the activation of lexical representations in meaningful contexts. Electrophysiological studies of spoken language comprehension have identified an event-related potential (ERP) that was sensitive to phonological properties of speech, which was termed the phonological mismatch negativity (PMN). With the PMN, early lexical processing could potentially be distinguished from processes of semantic integration in spoken language comprehension. However, the sensitivity of the PMN to phonological processing per se has been questioned, and it has additionally been suggested that the “PMN” is not separable from the N400, an ERP that is sensitive to semantic aspects of the input. Here, we investigated whether or not a separable PMN exists and if it reflects purely phonological aspects of the speech input. In the present experiment, ERPs were recorded from healthy young adults (N =24) while they listened to sentences and word lists, in which we manipulated semantic and phonological expectation and congruency of the final word. ERPs sensitive to phonological processing were elicited only when phonological expectancy was violated in lists of words, but not during normal sentential processing. This suggests a differential role of phonological processing in more or less meaningful contexts and indicates a very early influence of the overall context on lexical processing in sentences. PMID:16952338

  14. Electrophysiological evidence of nonlinear distortion products to two-tone stimuli.

    PubMed

    Rickman, M D; Chertoff, M E; Hecox, K E

    1991-06-01

    Spectral analysis of auditory-evoked potential recordings from ten normal-hearing subjects to two-tone signals revealed energy at difference tone (DT = f2-f1) and cubic difference (CDT = 2f1-f2) frequencies that was not present in the acoustic signal. Control experiments and calibrations provided substantial evidence supportive of the biological nature of these auditory nonlinearities, suggesting that they are not the result of electromagnetic, acoustic, or analytic artifact. Amplitudes of DT- and CDT-evoked responses were evaluated for rarefaction and condensation signals with f1 = 510 and 800 Hz across frequency ratios (f2/f1) of 1.16, 1.26, 1.36, and 1.46. Additionally, time-domain summation and subtraction of separately collected evoked responses to rarefaction and condensation signals were performed to demonstrate that these electrophysiological DT and CDT responses reflect their expected quadratic and cubic nature. Suggestions for development of clinical applications of assessing auditory nonlinearities using this methodology are provided. PMID:1918625

  15. The electrophysiological correlate of saliency: evidence from a figure-detection task.

    PubMed

    Straube, Sirko; Fahle, Manfred

    2010-01-11

    Although figure-ground segregation in a natural environment usually relies on multiple cues, we experience a coherent figure without usually noticing the individual single cues. It is still unclear how various cues interact to achieve this unified percept and whether this interaction depends on task demands. Studies investigating the effect of cue combination on the human EEG are still lacking. In the present study, we combined psychophysics, ERP and time-frequency analysis to investigate the interaction of orientation and spatial frequency as visual cues in a figure detection task. The figure was embedded in a matrix of Gabor elements, and we systematically varied figure saliency by changing the underlying cue configuration. We found a strong correlation between the posterior P2 amplitude and the perceived saliency of the figure: the P2 amplitude decreased with increasing saliency. Analogously, the power of the theta-band decreased for more salient figures. At longer latencies, the posterior P3 component was modulated in amplitude and latency, possibly reflecting increased decision confidence at higher saliencies. In conclusion, when the cue composition (e.g. one or two cues) or cue strength is changed in a figure detection task, first differences in the electrophysiological response reflect the perceived saliency and not directly the underlying cue configuration. PMID:19854163

  16. Development of microfluidic system and optical tweezers for electrophysiological investigations of an individual cell

    NASA Astrophysics Data System (ADS)

    Alrifaiy, A.; Bitaraf, N.; Lindahl, O.; Ramser, K.

    2010-08-01

    We present a new approach of combining Lab-on-a-chip technologies with optical manipulation technique for accurate investigations in the field of cell biology. A general concept was to develop and combine different methods to perform advanced electrophysiological investigations of an individual living cell under optimal control of the surrounding environment. The conventional patch clamp technique was customized by modifying the open system with a gas-tight multifunctional microfluidics system and optical trapping technique (optical tweezers). The system offers possibilities to measure the electrical signaling and activity of the neuron under optimum conditions of hypoxia and anoxia while the oxygenation state is controlled optically by means of a spectroscopic technique. A cellbased microfluidics system with an integrated patch clamp pipette was developed successfully. Selectively, an individual neuron is manipulated within the microchannels of the microfluidic system under a sufficient control of the environment. Experiments were performed to manipulate single yeast cell and red blood cell (RBC) optically through the microfluidics system toward an integrated patch clamp pipette. An absorption spectrum of a single RCB was recorded which showed that laser light did not impinge on the spectroscopic spectrum of light. This is promising for further development of a complete lab-on-a-chip system for patch clamp measurements.

  17. 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. PMID:9347609

  18. Mediastinal Packing for Intractable Coagulopathy in Acute Aortic Dissection (Types 1 and 2 DeBakey): A Life-Saving Technique—Report of Experiences

    PubMed Central

    Moeinipour, Aliasghar; Fathi, Mehdi; Sepehri Shamloo, Alireza; Amini, Shahram; Hoseinikhah, Hamid; Kianinejad, Akram

    2015-01-01

    Nonsurgical bleeding after complex thoracic aortic procedures (such as aortic dissection and aortic aneurysm) is a great challenge for cardiac surgeons because of severe coagulopathy, exsanguinous bleeding, and inevitable death. Temporary mediastinal packing (with sponge) in such cases is the only life-saving technique with good result in most cases. Herein, we presented three cases with acute aortic dissection with intractable bleeding that was successfully managed with mediastinal packing. PMID:26435855

  19. Acute Pneumonia.

    PubMed

    Arshad, Hammad; Fasanya, Adebayo; Cheema, Tariq; Singh, Anil C

    2016-01-01

    Acute pneumonia is an active infection of the lungs that results when an individual at risk gets exposed to a particular microbiological pathogen. Acute pneumonia is the leading cause of death in the United States that is attributable to an infection. The risk factors, pathogenesis, and microbiological organisms involved differ if the pneumonia develops in the community versus health care-associated environment. The development of concise and comprehensive guidelines has led to an improvement in the management of the problem. However, the emergence of multidrug-resistant organisms and the increase in the percentage of elderly population keep mortality risk very substantial. PMID:26919676

  20. Multiscale Electrophysiology Format: An Open Open-source Electrophysiology Format Using Data Compression, Encryption, and Cyclic Redundancy Check

    PubMed Central

    Brinkmann, Benjamin H.; Bower, Mark R.; Stengel, Keith A.; Worrell, Gregory A.; Stead, Matt

    2010-01-01

    Continuous, long-term (up to 10 days) electrophysiological monitoring using hybrid intracranial electrodes is an emerging tool for presurgical epilepsy evaluation and fundamental investigations of seizure generation. Detection of high-frequency oscillations and microseizures could provide valuable insights into causes and therapies for the treatment of epilepsy, but requires high spatial and temporal resolution. Our group is currently using hybrid arrays composed of up to 320 micro- and clinical macroelectrode arrays sampled at 32 kHz per channel with 18-bits of A/D resolution. Such recordings produce approximately 3 terabytes of data per day. Existing file formats have limited data compression capabilities, and do not offer mechanisms for protecting patient identifying information or detecting data corruption during transmission or storage. We present a novel file format that employs range encoding to provide a high degree of data compression, a three-tiered 128-bit encryption system for patient information and data security, and a 32-bit cyclic redundancy check to verify the integrity of compressed data blocks. Open-source software to read, write, and process these files are provided. PMID:19963940

  1. 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

  2. Electrophysiological effect of rotigaptide in rabbits with heart failure

    PubMed Central

    Liu, Yu; Li, Haitao; Xia, Wenfang; Yu, Shengbo; Huang, Congxin

    2012-01-01

    Introduction Rotigaptide is a new anti-arrhythmic peptide, which has recently been found to increase junctional conductance and prevent ischemia-induced ventricular tachycardia. In this study, we attempted to investigate the effects and mechanisms of rotigaptide on the vulnerability to ventricular arrhythmias in rabbits with heart failure (HF). Material and methods Chronic volume-pressure overload was used to induce HF. After rotigaptide infusion, an electrophysiological study was performed to record monophasic action potential (MAP), determine the effective refractory period (ERP) and ventricular fibrillation threshold (VFT), and assess the susceptibility to ventricular arrhythmia. Finally, real-time PCR was used to detect the changes of connexin 43 (Cx43) mRNA expression. Results HF rabbits exhibited significant down-regulation of Cx43 mRNA, increase of effective refractory period (ERP) and decrease of VFT (p < 0.05, respectively). These changes resulted in an increase of vulnerability to ventricular tachyarrhythmias (VT/VF). Rotigaptide administration shortened ERP (113.3 ±8.6 ms vs. 131.7 ±12.5 ms, p < 0.05), restored VFT (15.0 ±2.0 V vs. 6.3 ±1.4 V, p < 0.05), and decreased the vulnerability to VT/VF. However, short-term rotigaptide treatment had no significant effect on MAP duration (MAP duration at 90% repolarization: 169.3 ±6.0 ms vs. 172.7 ±6.2 ms, p > 0.05) or connexin 43 mRNA expression (p > 0.05). Conclusions Rotigaptide decreases the ERP, elevates VFT, and reduces the vulnerability to ventricular arrhythmias without changing Cx43 expression in rabbits with HF. It may be a promising antiarrhythmic drug for preventing ventricular arrhythmia in HF. PMID:24904675

  3. 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. PMID:26875725

  4. [Effect of the inhalation ++ anesthetic isoflurane on heart electrophysiology].

    PubMed

    Sarrión Auñón, J; Chorro Gascó, F J; Negueruela Cardo, A; Burguera Pérez, M; Sanchis Forés, J; Chuliá Campos, V; Palanca Sanfrancisco, J M; Such Belenguer, L; López Merino, V

    1992-01-01

    In two groups, A and B, both composed of 10 mongrel dogs, we studied the cardiac electrophysiologic effects of 1 and 1.5 MAC isoflurane administered by liquid injection in a closed circuit. In group B the study was done under pharmacological autonomic blockade (AB). With electrode catheters for programmed pacing and endocavitary potential recordings, we determined during the anesthesia with 1 and 1.5 MAC isoflurane: RR, spontaneous and paced AH, and HV intervals, corrected sinus recovery time (CSRT), Wenckebach point (WP), functional and effective refractory periods of atria (AFRP, AERP) and AV node (AVNFRP, AVNERP), and ventricular effective refractory period (VERP), these were compared to the ones obtained with a previous thiopental control. In group A, 1 MAC isoflurane increased over control: AERP and AH interval (p < 0.05), AFRP (p < 0.005), RR and AH paced intervals, WP, AVNFRP and VERP (p < 0.001), adding to these CSRT (p < 0.01) in 1.5 CAM. This level did not show differences with 1 MAC. In group B, 1 MAC isoflurane increased over control: AH (p < 0.05), RR, paced AH intervals, WP and AVNFRP (p < 0.001), adding to these AFRP and AERP (p < 0.05) in 1.5 MAC. This level increased with regard to 1 MAC: AFRP, AERP, AH paced interval and AVNERP (p < 0.05), and AVNFRP (p < 0.005). Isoflurane alone or with AB increased parameters of sinusal automaticity, atrial refractoriness, AV nodal conduction and refractoriness, increasing only without AB ventricular refractoriness and CSRT. With AB atrial and AV nodal refractoriness increased in an anesthetic depth dependent way. PMID:1439071

  5. Aldosterone-induced glycoproteins: electrophysiological-biochemical correlation.

    PubMed

    Szerlip, H M; Weisberg, L; Geering, K; Rossier, B C; Cox, M

    1988-05-01

    Aldosterone induces the synthesis of a group of glycoproteins (GP65,70) in toad urinary bladders which are potential effectors of the natriferic action of this hormone. In the present study we have confirmed that aldosterone produces a two-phase electrophysiological response. During the early phase (less than 3 h) short-circuit current and transepithelial conductance increase in parallel, while during the late phase (greater than 3 h) short-circuit current continues to increase without any further change in conductance. By biosynthetically labeling aldosterone-treated toad bladders with [35S]methionine either during the early (h 0-2 or 1-3) or the late (h 4-6 or 7-9) phases of the natriferic response, we have demonstrated that GP65,70 is synthesized as a late effect of aldosterone. Since synthesis of GP65,70 occurs at a time when the electromotive force of the Na+ pump is increasing, and since GP65,70 biochemically resembles the beta subunit of Na+/K+-ATPase, studies were undertaken to examine whether GP65,70 is the beta subunit. Purified amphibian renal beta subunit was analyzed by two-dimensional polyacrylamide gel electrophoresis and was found to have an isoelectric point and Mr value similar to those of GP65,70. However, when nitrocellulose blots containing wheat germ agglutinin-purified proteins from aldosterone-treated bladders were stained with monospecific polyclonal antibodies developed against the beta subunit, GP65,70 was not recognized, whereas a group of slightly more acidic proteins of similar Mr were recognized. Thus, GP65,70 is not the beta subunit of Na+/Ka+-ATPase. Further studies are needed to determine the cellular function of GP65,70. PMID:2835098

  6. Cardiac electrophysiologic effects of a new calcium antagonist, lacidipine.

    PubMed

    Cerbai, E; DeBonfioli Cavalcabó, P; Masini, I; Visentin, S; Giotti, A; Mugelli, A

    1990-04-01

    Lacidipine is a new 1,4-dihydropyridine derivative with potent and long-lasting antihypertensive activity. We used intracellular microelectrodes to characterize the electrophysiologic properties of lacidipine on different cardiac preparations. Lacidipine (10(-8) -10(-6) M) dose-dependently decreased contractility of driven sheep Purkinje fibers. For concentrations less than or equal to 10(-7) M, this effect was associated with a selective decrease of the plateau height. Higher concentrations (3 X 10(-7) and 10(-6) M), however, affected action potential amplitude, overshoot, and maximum rate of depolarization. In the same range of concentrations, lacidipine did not affect normal automaticity of guinea-pig sinus node and sheep Purkinje fibers. Lacidipine (10(-6) M) consistently blocked barium-induced abnormal automaticity in Purkinje fibers and reduced the amplitude and Vmax of the slow action potentials induced by histamine (10(-5) M) in guinea pig papillary muscle depolarized by potassium (22 mM). The effect of lacidipine on the slow inward current (Isi) was studied in shortened Purkinje fibers under voltage-clamp conditions. Lacidipine (10(-7)-10(-6) M) reduced the Isi without affecting the I-V relationship. None of the effects of lacidipine was reversed by 2-h washout. The results indicate that lacidipine has calcium-antagonistic properties in cardiac tissues. Its cardiac effects occur at concentrations 100 times higher than those active in the vascular smooth muscle. The lack of recovery of the lacidipine effects suggests that its interaction with the calcium channel may occur at an inner site of the cell membrane. PMID:1691391

  7. Electrophysiological and Anatomical Correlates of Spinal Cord Optical Coherence Tomography.

    PubMed

    Giardini, Mario E; Zippo, Antonio G; 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

  8. Electrophysiologic changes in patients with untreated primary hypothyroidism.

    PubMed

    Eslamian, Fariba; Bahrami, Amir; Aghamohammadzadeh, Naser; Niafar, Mitra; Salekzamani, Yaghoub; Behkamrad, Keyvan

    2011-06-01

    Thyroid diseases may cause signs and symptoms of neuromuscular dysfunction. Hypothyroidism has been associated with the clinical features of proximal muscle weakness, mononeuropathy, and sensorimotor polyneuropathy. This study aimed at evaluating the electrophysiologic findings in patients with untreated spontaneous hypothyroidism and comparing them with a healthy control group. In a case-control cross-sectional study, 40 patients with definite diagnosis of clinical hypothyroidism and 40 healthy control subjects were evaluated by electromyography and nerve conduction studies in the specialized clinic of the Tabriz University of Medical Sciences during an 18-month period. Seven male and 33 female patients with a mean age of 39.5 ± 11.8 years were enrolled. In this group, there were 12 cases (30%) with clinical muscle weakness, with severity of approximately 4/5, 18 cases (45%) with decreased or absent deep tendon reflexes, 6 cases (15%) with neuropathy, including 4 sensory and 2 sensorimotor, of which 5 cases were mild and 1 case was moderate, 3 cases (7.5%) with myopathy, and 13 cases (32.5%) with carpal tunnel syndrome, which was mild in 7, moderate in 10, and severe in 2 hands. Patients with neuropathy were significantly older than those without neuropathy (P = 0.001). There was no significant relation between gender, duration of the disease, serum TSH level, and the presence of clinical muscle weakness with the occurrence of neuropathy or myopathy. Female gender, increasing age, duration of the disease, and the frequency of clinical weakness were, however, significantly related to the presence of carpal tunnel syndrome (P < 0.05). In conclusion, in patients with untreated primary hypothyroidism, majority had the carpal tunnel syndrome. Mild neuropathy mainly of sensory type and myopathy were uncommon and rare findings, respectively. Early treatment would hinder the progression of mentioned abnormalities and minimize their occurrence. PMID:21633261

  9. Electrophysiological measures of cognition in biological psychiatry: some cautionary notes.

    PubMed

    Barceló, F; Gale, A

    1997-12-01

    Research into the electrophysiological correlates of mental illness is currently expanding, largely because of the availability of relatively inexpensive and powerful computers. However, improvements in technology do not always lead to enhanced methodological procedures; thus, there are concerns over the proper interpretation of the results of these investigations. Our argument is that electroencephalographic (EEG) research into psychopathology of psychiatric diseases should adopt a cognitivist model of mental dysfunction rather than a neurologist model of brain disease. Cognitive science has significant potential as an integrative framework for theorizing and researching psychiatric disorders and their treatment. Models of human cognitive functioning have rather special and unique features; these will make their impact upon the nature of both the analysis and interpretation of EEG data. The adoption of a sound model of brain function has implications for the methods to be used at different successive stages of the research process. We address a number of methodological requirements pertaining to: the recording and analysis of EEG signals, the laboratory context, the nature of the tasks, and the attribution of obtained effects. However, there are grounds for great caution. Even if the mapping of electrical changes in brain activity leads to a good approximation of the temporal and spatial dynamics of higher brain function, exploitation of such information presupposes a deeper understanding of both human cognition and the physiological basis of the EEG than is often displayed in the literature. To demonstrate this fundamental point, we draw a number of comparisons between traditional neurological approaches to brain assessment and contemporary cognitive psychophysiology. PMID:9522268

  10. Evolving anatomic and electrophysiologic considerations associated with Fontan conversion.

    PubMed

    Mavroudis, Constantine; Backer, Carl Lewis; Deal, Barbara J; Stewart, Robert D; Franklin, Wayne H; Tsao, Sabrina; Ward, Kendra

    2007-01-01

    The principles of Fontan conversion with arrhythmia surgery are to restore the cardiac anatomy by converting the original atriopulmonary connection to a total cavopulmonary artery extracardiac connection and treat the underlying atrial arrhythmias. Successful outcomes of this procedure are dependent on a thorough understanding of several factors: the patient's fundamental diagnosis of single-ventricle anatomy, the resultant cardiac configuration from the original atriopulmonary Fontan connection, right atrial dilatation that leads to atrial flutter or fibrillation, and associated congenital cardiac anomalies. The purpose of this article is to present some of the more challenging anatomic and electrophysiologic problems we have encountered with Fontan conversion and arrhythmia surgery and the innovative solutions we have used to treat them. The cases reviewed herein include: takedown of a Bjork-Fontan modification, right ventricular hypertension and tricuspid regurgitation after atriopulmonary Fontan for pulmonary atresia and intact ventricular septum, takedown of atrioventricular valve isolation patch for right-sided maze procedure, resultant hemodynamic considerations leading to intraoperative pulmonary vein stenosis after Fontan conversion, unwanted inferior vena cava retraction during the extracardiac connection, right atrial cannulation in the presence of a right atrial clot, distended left superior vena cava causing left pulmonary vein stenosis, dropped atrial septum, and the modified right-sided maze procedure for various single-ventricle pathology. Since 1994 we have performed Fontan conversion with arrhythmia surgery on 109 patients with a 0.9% mortality rate. We attribute our program's success in no small measure to the strong collaborative efforts of the cardiothoracic surgery and cardiology teams. PMID:17434005

  11. Electrophysiological correlates of melodic processing in congenital amusia.

    PubMed

    Omigie, Diana; Pearce, Marcus T; Williamson, Victoria J; Stewart, Lauren

    2013-08-01

    Music listening involves using previously internalized regularities to process incoming musical structures. A condition known as congenital amusia is characterized by musical difficulties, notably in the detection of gross musical violations. However, there has been increasing evidence that individuals with the disorder show preserved musical ability when probed using implicit methods. To further characterize the degree to which amusic individuals show evidence of latent sensitivity to musical structure, particularly in the context of stimuli that are ecologically valid, electrophysiological recordings were taken from a sample of amusic and control participants as they listened to real melodies. To encourage them to pay attention to the music, participants were asked to detect occasional notes in a different timbre. Using a computational model of auditory expectation to identify points of varying levels of expectedness in these melodies (in units of information content (IC), a measure which has an inverse relationship with probability), ERP analysis investigated the extent to which the amusic brain differs from that of controls when processing notes of high IC (low probability) as compared to low IC ones (high probability). The data revealed a novel effect that was highly comparable in both groups: Notes with high IC reliably elicited a delayed P2 component relative to notes with low IC, suggesting that amusic individuals, like controls, found these notes more difficult to evaluate. However, notes with high IC were also characterized by an early frontal negativity in controls that was attenuated in amusic individuals. A correlation of this early negative effect with the ability to make accurate note expectedness judgments (previous data collected from a subset of the current sample) was shown to be present in typical individuals but compromised in individuals with amusia: a finding in line with evidence of a close relationship between the amplitude of such a

  12. Electrophysiological changes elicited by auditory stimuli given a positive or negative value: a study comparing anhedonic with hedonic subjects.

    PubMed

    Pierson, A; Ragot, R; Ripoche, A; Lesevre, N

    1987-07-01

    The present experiment investigates in 'normal' subjects the relationship between personality characteristics (anhedonia versus hedonia) and the influence of the affective value of acoustic stimuli (positive, negative, neutral) on various electrophysiological indices reflecting either tonic activation or phasic arousal (EEG power spectra, contingent negative variation: CNV, heart rate, skin potential responses: SPR) as well as on behavioural indices (reaction time: RT). Eighteen subjects were divided into two groups according to their scores at two self-rating questionnaires, the Chapman's Physical Anhedonia Scale (PAS) and the Beck-Weissman's Dysfunctional Attitude Scale (DAS) that quantifies cognitive distortions presumed to constitute high risk for depression: 9 with high scores at both scales formed the A group (Anhedonic-dysfunctional), 9 with low scores at both scales, the H group (Hedonic-adapted) The electrophysiological indices were recorded during 3 situations: the first one was a classical CNV paradigm with a motor reaction time task in which one of 3 tones of different pitch represented the warning stimulus S1; during the second, conditioning phase, two of these tones were associated with either a success (and reward) or a failure (and punishment) during a memory task in order to make them acquire either a positive or a negative affective value; the third situation consisted in the repeating of the first CNV paradigm in order to test the effect of the positive and the negative stimuli versus the neutral one on RTs and electrophysiological data. Significant between-group differences were found regarding tonic activation as well as phasic arousal indices from the very beginning of the experiment when all stimuli were neutral ones, the anhedonics exhibiting higher activation and arousal than the hedonics at the cortical (increased CNV amplitude, increased power in the beta frequency band), cardiovascular (higher heart rate habituating more slowly) and

  13. Acute Pancreatitis

    PubMed Central

    Geokas, Michael C.

    1972-01-01

    For many decades two types of acute pancreatitis have been recognized: the edematous or interstitial and the hemorrhagic or necrotic. In most cases acute pancreatitis is associated with alcoholism or biliary tract disease. Elevated serum or urinary α-amylase is the most important finding in diagnosis. The presence of methemalbumin in serum and in peritoneal or pleural fluid supports the diagnosis of the hemorrhagic form of the disease in patients with a history and enzyme studies suggestive of pancreatitis. There is no characteristic clinical picture in acute pancreatitis, and its complications are legion. Pancreatic pseudocyst is probably the most common and pancreatic abscess is the most serious complication. The pathogenetic principle is autodigestion, but the precise sequence of biochemical events is unclear, especially the mode of trypsinogen activation and the role of lysosomal hydrolases. A host of metabolic derangements have been identified in acute pancreatitis, involving lipid, glucose, calcium and magnesium metabolism and changes of the blood clotting mechanism, to name but a few. Medical treatment includes intestinal decompression, analgesics, correction of hypovolemia and other supportive and protective measures. Surgical exploration is advisable in selected cases, when the diagnosis is in doubt, and is considered imperative in the presence of certain complications, especially pancreatic abscess. PMID:4559467

  14. Mild axonal neuropathy of children during treatment for acute lymphoblastic leukaemia.

    PubMed

    Reinders-Messelink, H A; Van Weerden, T W; Fock, J M; Gidding, C E; Vingerhoets, H M; Schoemaker, M M; Göeken, L N; Bökkerink, J P; Kamps, W A

    2000-01-01

    Neurophysiological functioning was studied prospectively in children treated for acute lymphoblastic leukaemia with a low dose vincristine regime (8 x 1.5 mg/m2/dose), to obtain more insight into vincristine neuropathy. A WHO neurotoxicity score was estimated and vibration sense and electrophysiological measurements were taken at standardized times during vincristine treatment. The WHO neurotoxicity score showed decreased or disappearance of Achilles tendon reflexes, and mild sensory disturbances, but a grade 3-4 neurotoxicity was not demonstrated by any of the children. Vibration perception thresholds increased progressively during treatment and amplitudes of action potentials of peroneal and sensory ulnar and median nerves decreased, whereas nerve conduction velocities stayed unchanged. Both vibration perception thresholds and the electrophysiological findings hardly exceeded the limits of normality. We conclude that children treated for acute lymphoblastic leukaemia with a low dose vincristine regimen have mild axonal neuropathy which may be responsible for the motor problems in these children. PMID:11030069

  15. Restoring visual function to blind mice with a photoswitch that exploits electrophysiological remodeling of retinal ganglion cells

    PubMed Central

    Tochitsky, Ivan; Polosukhina, Aleksandra; Degtyar, Vadim E.; Gallerani, Nicholas; Smith, Caleb M.; Friedman, Aaron; Van Gelder, Russell N.; Trauner, Dirk; Kaufer, Daniela; Kramer, Richard H.

    2014-01-01

    Summary Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are blinding diseases caused by the degeneration of rods and cones, leaving the remainder of the visual system unable to respond to light. Here we report a chemical photoswitch named DENAQ that restores retinal responses to white light of intensity similar to ordinary daylight. A single intraocular injection of DENAQ photosensitizes the blind retina for days, restoring electrophysiological and behavioral responses with no toxicity. Experiments on mouse strains with functional, non-functional, or degenerated rods and cones show that DENAQ is effective only in retinas with degenerated photoreceptors. DENAQ confers light sensitivity on a hyperpolarization-activated inward current that is enhanced in degenerated retina, enabling optical control of retinal ganglion cell firing The acceptable light sensitivity, favorable spectral sensitivity, and selective targeting to diseased tissue make DENAQ a prime drug candidate for vision restoration in patients with end-stage RP and AMD. PMID:24559673

  16. Restoring visual function to blind mice with a photoswitch that exploits electrophysiological remodeling of retinal ganglion cells.

    PubMed

    Tochitsky, Ivan; Polosukhina, Aleksandra; Degtyar, Vadim E; Gallerani, Nicholas; Smith, Caleb M; Friedman, Aaron; Van Gelder, Russell N; Trauner, Dirk; Kaufer, Daniela; Kramer, Richard H

    2014-02-19

    Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are blinding diseases caused by the degeneration of rods and cones, leaving the remainder of the visual system unable to respond to light. Here, we report a chemical photoswitch named DENAQ that restores retinal responses to white light of intensity similar to ordinary daylight. A single intraocular injection of DENAQ photosensitizes the blind retina for days, restoring electrophysiological and behavioral responses with no toxicity. Experiments on mouse strains with functional, nonfunctional, or degenerated rods and cones show that DENAQ is effective only in retinas with degenerated photoreceptors. DENAQ confers light sensitivity on a hyperpolarization-activated inward current that is enhanced in degenerated retina, enabling optical control of retinal ganglion cell firing. The acceptable light sensitivity, favorable spectral sensitivity, and selective targeting to diseased tissue make DENAQ a prime drug candidate for vision restoration in patients with end-stage RP and AMD. PMID:24559673

  17. Prevalence and factors associated with false positive suspicion of acute aortic syndrome: experience in a patient population transferred to a specialized aortic treatment center

    PubMed Central

    Raymond, Chad E.; Aggarwal, Bhuvnesh; Schoenhagen, Paul; Kralovic, Damon M.; Kormos, Kristopher; Holloway, David

    2013-01-01

    Study objective Acute aortic syndrome (AAS) is a medical emergency that requires prompt diagnosis and treatment at specialized centers. We sought to determine the frequency and etiology of false positive activation of a regional AAS network in a patient population emergently transferred for suspected AAS. Methods We evaluated 150 consecutive patients transferred from community emergency departments directly to our Cardiac Intensive Care Unit (CICU) with a diagnosis of suspected AAS between March, 2010 and August, 2011. A final diagnosis of confirmed acute Type A, acute Type B dissection, and false positive suspicion of dissection was made in 63 (42%), 70 (46.7%) and 17 (11.3%) patients respectively. Results Of the 17 false positive transfers, ten (58.8%) were suspected Type A dissection and seven (41.2%) were suspected Type B dissection. The initial hospital diagnosis in 15 (88.2%) patients was made by a computed tomography (CT) scan and 10 (66.6%) of these patients required repeat imaging with an ECG-synchronized CT to definitively rule out AAS. Five (29.4%) patients had prior history of open or endovascular aortic repair. Overall in-hospital mortality was 9.3%. Conclusions The diagnosis of AAS is confirmed in most patients emergently transferred for suspected AAS. False positive activation in this setting is driven primarily by uncertainty secondary to motion-artifact of the ascending aorta and the presence of complex anatomy following prior aortic intervention. Network-wide standardization of imaging strategies, and improved sharing of imaging may further improve triage of this complex patient population. PMID:24400203

  18. Acute undifferentiated febrile illness in adult hospitalized patients: the disease spectrum and diagnostic predictors - an experience from a tertiary care hospital in South India.

    PubMed

    Chrispal, Anugrah; Boorugu, Harikishan; Gopinath, Kango Gopal; Chandy, Sara; Prakash, John Antony Jude; Thomas, Elsa Mary; Abraham, Asha Mary; Abraham, O C; Thomas, Kurien

    2010-10-01

    Local prevalences of individual diseases influence the prioritization of the differential diagnoses of a clinical syndrome of acute undifferentiated febrile illness (AFI). This study was conducted in order to delineate the aetiology of AFI that present to a tertiary hospital in southern India and to describe disease-specific clinical profiles. An 1-year prospective, observational study was conducted in adults (age >16 years) who presented with an undifferentiated febrile illness of duration 5-21 days, requiring hospitalization. Blood cultures, malarial parasites and febrile serology (acute and convalescent), in addition to clinical evaluations and basic investigations were performed. Comparisons were made between each disease and the other AFIs. A total of 398 AFI patients were diagnosed with: scrub typhus (47.5%); malaria (17.1%); enteric fever (8.0%); dengue (7.0%); leptospirosis (3.0%); spotted fever rickettsiosis (1.8%); Hantavirus (0.3%); alternate diagnosis (7.3%); and unclear diagnoses (8.0%). Leucocytosis, acute respiratory distress syndrome, aseptic meningitis, mild serum transaminase elevation and hypoalbuminaemia were independently associated with scrub typhus. Normal leukocyte counts, moderate to severe thrombocytopenia, renal failure, splenomegaly and hyperbilirubinaemia with mildly elevated serum transaminases were associated with malaria. Rash, overt bleeding manifestations, normal to low leukocyte counts, moderate to severe thrombocytopenia and significantly elevated hepatic transaminases were associated with dengue. Enteric fever was associated with loose stools, normal to low leukocyte counts and normal platelet counts. It is imperative to maintain a sound epidemiological database of AFIs so that evidence-based diagnostic criteria and treatment guidelines can be developed. PMID:20870680

  19. Clinical Efficacy of Electroneurography in Acute Facial Paralysis

    PubMed Central

    2016-01-01

    The estimated incidence of acute facial paralysis is approximately 30 patients per 100000 populations annually. Facial paralysis is an extremely frightening situation and gives extreme stress to patients because obvious disfiguring face may cause significant functional, aesthetic, and psychological disturbances. For stressful patients with acute facial paralysis, it is very important for clinicians to answer the questions like whether or not their facial function will return to normal, how much of their facial function will be recovered, and how long this is going to take. It is also important for clinicians to treat the psychological aspects by adequately explaining the prognosis, in addition to providing the appropriate medical treatment. For decades, clinicians have used various electrophysiologic tests, including the nerve excitability test, the maximal stimulation test, electroneurography, and electromyography. In particular, electroneurography is the only objective measure that is useful in early stage of acute facial paralysis. In this review article, we first discuss the pathophysiology of injured peripheral nerve. And then, we describe about various electrophysiologic tests and discuss the electroneurography extensively. PMID:27144227

  20. Clinical Efficacy of Electroneurography in Acute Facial Paralysis.

    PubMed

    Lee, Dong-Hee

    2016-04-01

    The estimated incidence of acute facial paralysis is approximately 30 patients per 100000 populations annually. Facial paralysis is an extremely frightening situation and gives extreme stress to patients because obvious disfiguring face may cause significant functional, aesthetic, and psychological disturbances. For stressful patients with acute facial paralysis, it is very important for clinicians to answer the questions like whether or not their facial function will return to normal, how much of their facial function will be recovered, and how long this is going to take. It is also important for clinicians to treat the psychological aspects by adequately explaining the prognosis, in addition to providing the appropriate medical treatment. For decades, clinicians have used various electrophysiologic tests, including the nerve excitability test, the maximal stimulation test, electroneurography, and electromyography. In particular, electroneurography is the only objective measure that is useful in early stage of acute facial paralysis. In this review article, we first discuss the pathophysiology of injured peripheral nerve. And then, we describe about various electrophysiologic tests and discuss the electroneurography extensively. PMID:27144227

  1. First evidence of collective alpha particle effect on toroidal Alfv{acute e}n eigenmodes in the TFTR D-T experiment

    SciTech Connect

    Wong, K.L.; Schmidt, G.L.; Batha, S.H.; Bell, R.; Chang, Z.; Chen, L.; Darrow, D.S.; Duong, H.H.; Fu, G.Y.; Hammett, G.W.; Levinton, F.; Majeski, R.; Mazzucato, E.; Nazikian, R.; Owens, D.K.; Petrov, M.; Rogers, J.H.; Schilling, G.; Wilson, J.R.

    1996-03-01

    The alpha particle effect on the excitation of toroidal Alfv{acute e}n eigenmodes (TAE) was investigated in deuterium-titrium (D-T) plasmas in the Tokamak Fusion Test Reactor. rf power was used to position the plasma near the instability threshold, and the alpha particle effect was inferred from the reduction of rf power threshold for TAE instability in D-T plasmas. Initial calculations indicate that the alpha particles contribute 10{percent}{endash}30{percent} of the total drive in a D-T plasma with 3 MW of peak fusion power. {copyright} {ital 1996 The American Physical Society.}

  2. A microfluidic device for whole-animal drug screening using electrophysiological measures in the nematode C. elegans

    PubMed Central

    Hulme, S. Elizabeth; Roberts, William M.; Robinson, Kristin J.; Laromaine, Anna; Lindsay, Theodore H.; Whitesides, George M.; Weeks, Janis C.

    2012-01-01

    This paper describes the fabrication and use of a microfluidic device for performing whole-animal chemical screens using non-invasive electrophysiological readouts of neuromuscular function in the nematode worm, C. elegans. The device consists of an array of microchannels to which electrodes are attached to form recording modules capable of detecting the electrical activity of the pharynx, a heart-like neuromuscular organ involved in feeding. The array is coupled to a tree-like arrangement of distribution channels that automatically delivers one nematode to each recording module. The same channels are then used to perfuse the recording modules with test solutions while recording the electropharyngeogram (EPG) from each worm with sufficient sensitivity to detect each pharyngeal contraction. The device accurately reported the acute effects of known anthelmintics (anti-nematode drugs) and also correctly distinguished a specific drug-resistant mutant strain of C. elegans from wild type. The approach described here is readily adaptable to parasitic species for the identification of novel anthelmintics. It is also applicable in toxicology and drug discovery programs for human metabolic and degenerative diseases for which C. elegans is used as a model. PMID:22588281

  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. PMID:27163548

  4. Increased BDNF protein expression after ischemic or PKC epsilon preconditioning promotes electrophysiologic changes that lead to neuroprotection

    PubMed Central

    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. PMID:25370861

  5. 3D Image-Guided Automatic Pipette Positioning for Single Cell Experiments in vivo.

    PubMed

    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

  6. 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

  7. Electrophysiological characterization of adult-onset Niemann-Pick type C disease.

    PubMed

    Iodice, Rosa; Dubbioso, Raffaele; Topa, Antonietta; Ruggiero, Lucia; Pisciotta, Chiara; Esposito, Marcello; Tozza, Stefano; Santoro, Lucio; Manganelli, Fiore

    2015-01-15

    In infantile and juvenile Niemann-Pick type C (NPC) disease electrophysiological studies have shown central (CNS) and peripheral (PNS) nervous system abnormalities. However, an extensive electrophysiological evaluation of CNS and PNS in adult form of NPC is still lacking. The aim of the study is to assess in adult-onset NPC disease the involvement of CNS and PNS by a multimodal electrophysiological approach. Three patients affected by adult form of NPC disease underwent electrophysiological evaluation including nerve conduction study (NCS), magnetic motor (MEPs), visual (VEPs), somatosensory (SSEPs) and brainstem auditory (BAEPs) evoked potentials. NCS, MEPs, VEPs and upper limb SSEPs were normal. Lower limb SSEPs were abnormal in all patients and abnormalities were consistent with a length-dependent process affecting the central somatosensory pathway. BAEPs were abnormal in all patients with both peripheral and central impairment of auditory pathway. Our electrophysiological findings suggest that auditory and lower limb somatosensory pathways are constantly affected in adult-onset form of NPC disease. The involvement of PNS, pyramidal, visual and upper limb somatosensory pathways might occur later during the course of disease. PMID:25537619

  8. 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

    2015-01-01

    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 moto