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Bradley, Peter Mark James. "A Novel Fibre-Optic Probe for Simultaneous Extracellular Electrical and Intracellular Fluorescence Recording in Neurones In Situ and In Vito." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503894.
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Kobaïter, Maarawi Sandra. "Effets électrophysiologiques de la stimulation du cortex moteur sur les noyaux somatosensorielslatéraux du thalamus : étude expérimentale sur un modèle de stimulation du cortex moteur chez le chat." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10100/document.
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La stimulation du cortex moteur (SCM) est une technique neurochirurgicale utilisée chez l'Homme comme traitement de dernier recours pour les douleurs neuropathiques rebelles. Elle a été développée sur des bases empiriques. Ce travail vise à une meilleure compréhension des mécanismes d'action de la SCM qui restent incomplètement élucidés à ce jour. L'objectif de cette thèse est d'étudier les effets électrophysiologiques de la SCM au niveau thalamique, chez un modèle de chat. La première partie de cette étude a consisté à établir une cartographie stéréotaxique du cortex moteur (CM) de cet animal, inexistante dans la littérature. À partir de cette cartographie, nous avons pu établir et valider un modèle de SCM chez cet animal, implanté de façon mini-invasive. La deuxième partie de ce travail a consisté à recueillir et analyser les changements électrophysiologiques de l'activité extracellulaire unitaire des cellules du noyau ventro-postéro-latéral (VPL) du thalamus, induits par différents protocoles de SCM. Nos résultats montrent une modulation de l'activité des cellules du VPL par la SCM, qui varie en fonction de la nature nociceptive ou non de la cellule thalamique. La SCM augmente l'activité des cellules non nociceptives et diminue celle des cellules nociceptives. Pour une cellule donnée, l'effet observé est indépendant de la correspondance somatotopique entre la région du CM stimulée et la localisation sur le corps du champ récepteur de la cellule enregistrée. Ce travail a ainsi permis de montrer l'existence d'une neuro-modulation différentielle du VPL par la SCM en fonction de la nature de la cellule thalamiqueMotor cortex stimulation (MCS) is a neurosurgical technique developed on empirical basis and currently used as last solution for patients suffering from refractory neuropathic pain. The present work is a new attempt among other contemporary studies aiming to understand the mechanisms of action of MCS, which remain incompletely elucidated at that time. The main objective of this thesis is to study the electrophysiological effect of MCS at the thalamic level, in a cat model. The first part of this work aims to establish the stereotactic somatotopic map of the cat motor cortex (MC), not available so far in the literature. Based on this mapping, we created and validated a cat model of MCS, using a mini-invasive electrode implantation. The second part of this study included a recording and analysis of the potential changes of the unitary extracellular activity of cells located in the thalamic ventro-postero-lateral (VPL) nucleus, induced by different MCS protocols. Our results indicate a modulation of the VPL cells activity after MCS, depending on the nociceptive or non-nociceptive nature of the recorded thalamic cell. MCS increases the activity of non-nociceptive cells and decreases that of nociceptive cells. For a given cell the matching between the somatotopy of the MC stimulated region and the receptive field localization of the recorded thalamic cell is not a prerequisite for obtaining such a modulation. In conclusion, the present work has proven a neuro-modulatory differential effect of MCS on nociceptive and non-nociceptive cells in the thalamic VPL nucleus
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Blum, Richard Alan. "An Electronic System for Extracellular Neural Stimulation and Recording." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16192.
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A system for extracellular neural interfacing that had the capability for stimulation and recording at multiple electrodes was presented. As the core of this system was a custom integrated circuit (IC) that contained low-noise amplifiers, stimulation buffers, and artifact-elimination circuitry. The artifact-elimination circuitry was necessary to prevent the activity of the stimulation buffers from interfering with the normal functioning of the low-noise amplifiers.
The integrated circuits were fabricated in in a 0.35 micron CMOS process. We measured input-referred noise levels for the amplifiers as low as 3.50 microvolts (rms) in the in the bandwidth 30 Hz-3 kHz, corresponding to the frequency range of neural action potentials. The power consumption was 120 microwatts, corresponding to a noise-efficiency factor of 14.5. It was possible to resume recording signals within 2 ms of a stimulation, using the same electrode for both stimulation and recording.
A filtering algorithm to remove the post-discharge artifact was also presented. The filtering was implemented using a field-programmable gate array (FPGA). The filtering algorithm itself consisted of blanking for the duration of the stimulation and artifact-elimination, followed by a wavelet de-noising. The wavelet de-noising split the signal into frequency ranges, discarded those ranges that did not correspond to neural signals, applied a threshold to the retained signals, and recombined the different frequency ranges into a single signal. The combination of the filtering with the artifact-elimination IC resulted in the capability for artifact-free recordings.
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Bernstein, Jacob (Jacob Gold). "Development of extracellular electrophysiology methods for scalable neural recording." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107581.
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Thesis: Ph. D., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references.
In order to map the dynamics of neural circuits in mammalian brains, there is a need for tools that can record activity over large volumes of tissue and correctly attribute the recorded signals to the individual neurons that generated them. High-resolution neural activity maps will be critical for the discovery of new principles of neural coding and neural computation, and to test computational models of neural circuits. Extracellular electrophysiology is a neural recording method that has been developed to record from large populations of neurons, but well-known problems with signal attribution pose an existential threat to the viability of further system scaling, as analyses of network function become more sensitive to errors in attribution. A key insight is that blind-source separation algorithms such as Independent Component Analysis may ameliorate problems with signal attribution. These algorithms require recording signals at much finer spatial resolutions than existing probes have accomplished, which places demands on recording system bandwidth. We present several advances to technologies in neural recording systems, and a complete neural recording system designed to investigate the challenges of scaling electrophysiology to whole brain recording. We have developed close-packed microelectrode arrays with the highest density of recording sites yet achieved, for which we built our own data acquisition hardware, developed with a computational architecture specifically designed to scale to over several orders of magnitude. We also present results from validation experiments using colocalized patch clamp recording to obtain ground-truth activity data. This dataset provides immediate insight into the nature of electrophysiological signals and the interpretation of data collected from any electrophysiology recording system. This data is also essential in order to optimize probe development and data analysis algorithms which will one day enable whole-brain activity mapping.
by Jacob G. Bernstein.
Ph. D.
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Sayed, Herbawi Abdalrahman [Verfasser], and Oliver [Akademischer Betreuer] Paul. "High-density CMOS probes for large-scale extracellular neural recording." Freiburg : Universität, 2020. http://d-nb.info/1226657265/34.
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Silpa, Nagari. "NANOSTRUCTURED SENSORS FOR IN-VIVO NEUROCHEMICAL RECORDING." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/487.
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L-glutamate plays a vital role in central nervous system. It is a neurotransmitterassociated with several neurological disorders like Parkinson's disease, epilepsyand stroke. Continuous and fast monitoring of this neurotransmitter has become amajor concern for neuroscientists throughout the world. A simple, sensitive, and reliable L-glutamate microsensor with short responsetime has been developed using ceramic-based microelectrode arrays with platinum recording sites. The electrodes were modified by electrodeposition of Platinum black (Pt-black) to detect hydrogen peroxide (H2O2) which was produced by enzymatic reactions of glutamate oxidase immobilized on the electrode surface. Modification of Pt electrodes with Pt-black has been adoptedbecause the microscale roughness of Pt-black increases the effective surface area of the electrode and promotes efficiency of H2O2 electro-oxidation. The modified Pt recording sites were coated with m-phenylenediamine (mPD) and L-glutamate oxidase (L-GluOx). mPD acts as an barrier for extracellular interferents such as ascorbic acid and dopamine, thus increasing the selectivity of electrode for Glutamate (Glu). This modified microsensor was highly sensitive to H2O2(686.3??156.48 ??AmM-1cm-2), and Glutamate (492.2??112.67 ??AmM-1cm-2) at 700mV versus Ag/AgCl reference. Deposition of Pt nano-particles on recording sites enhanced the sensitivity to H2O2 by 2 times and the sensitivity to glutamate by 1.5 times.
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Nagari, Silpa. "Nano-structured sensors for in-vivo neurochemical recording." Lexington, Ky. : [University of Kentucky Libraries], 2007. http://hdl.handle.net/10225/735.
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Thesis (M.S.)--University of Kentucky, 2007.Title from document title page (viewed on March 24, 2008). Document formatted into pages; contains: ix, 55 p. : ill. (some col.). Includes abstract and vita. Includes bibliographical references (p. 53-54).
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Watts, Joanne. "Regulation of extracellular arginine levels in the hippocampus in vivo." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404830.
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Kuykendal, Michelle Lea. "Closed-loop optimization of extracellular electrical stimulation for targeted neuronal activation." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52303.
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We have developed a high-throughput system of closed-loop electrical stimulation and optical recording that facilitates the rapid characterization of extracellular stimulus-evoked neural activity. The ability to selectively stimulate a neuron is a defining characteristic of next-generation neural prostheses. Greater stimulus control and differential activation of specific neuronal populations allows for prostheses that better mimic their biological counterparts.
In our system, we deliver square current pulses using a microelectrode array; automated real-time image processing of high-speed digital video identifies the neuronal response; and a feedback controller alters the applied stimulus to achieve a targeted response. The system controller performs directed searches within the strength-duration (SD) stimulus parameter space to build probabilistic neuronal activation curves. An important feature of this closed-loop system is a reduction in the number of stimuli needed to derive the activation curves when compared to the more commonly used open-loop system: this allows the closed-loop system to spend more time probing stimulus regions of interest in the multi-parameter waveform space, facilitating high resolution analysis.
The stimulus-evoked activation data were well-fit to a sigmoid model in both the stimulus strength (current) and duration (pulse width) slices through the waveform space. The 2-D analysis produced a set of probability isoclines corresponding to each neuron-electrode pairing, which were fit to the SD threshold model described by Lapique (1907). We show that stimulus selectivity within a given neuron pair is possible in the one-parameter search space by using multiple stimulation electrodes. Additionally, by applying simultaneous stimuli to adjacent electrodes, the interaction between stimuli alters the neuronal activation threshold. The interaction between simultaneous multi-electrode multi-parameter stimulus waveforms creates an opportunity for increased stimulus selectivity within a population.
We demonstrated that closed-loop imaging and micro-stimulation technology enable the study of neuronal excitation across a large parameter space, which is requisite for controlling neuronal activation in next generation clinical solutions.
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Patel, Manoj Kumar. "An investigation into electrophysiological changes associated with myocardial ischaemia and reperfusion using extracellular and intracellular recording techniques." Thesis, Coventry University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308953.
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Czeschik, Anna [Verfasser], Bernhard [Akademischer Betreuer] Wolfrum, and Jörg [Akademischer Betreuer] Fitter. "Nanocavity arrays for extracellular recording and stimulation of electroactive cell systems / Anna Czeschik ; Bernhard Wolfrum, Jörg Fitter." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1130151530/34.
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Sörensen, Sören Per. "Development of a cell-based drug screening platform : extracellular recording and electrochemical impedance spectroscopy on microelectrode array chips." Thesis, University of Bath, 2007. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486476.
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Two established methods, Electrochemical Impedance Spectroscopy (EIS) and extracellular recording, were implemented into a technology platform for non-invasive whole-cell biosensing. Electrical activity of cardiomyocytes and cell-substrate interaction of human ovarian cancer cells was monitored on electrode array chips. The performance of cells inside a microfluidic or closed low volume environment was investigated. Prior to the development of the entire microfluidic platform the two transducing methods were evaluated in single experiments. Processes as cellular attachment and detachment were monitored using EIS and single frequency impedance sensing. Electrodes of different size and structure were employed and compared for their impedance response. It was shown that small electrodes (A = 9·10-6 cm²) are more sensitive to cell-substrate interaction than larger ones (A = 9·10-5 cm²) and that the frequency used for analysis has a profound influence on the sensitivity. Data were modelled using a common equivalent circuit that represents a cell layer on an electrode resulting in an increase of the impedance magnitude by <170 % due to cell attachment. In order to demonstrate the potential of this method for biomedical applications, experiments related to anti-cancer strategies were performed. Cell detachment was induced by addition of synthetic integrin ligands and by hypericin mediated photodynamic therapy and monitored with impedance-based biosensing. Electrical activity of cardiomyocytes cultured on microelectrode arrays was monitored inside a microfluidic system. The chronotropic drug isoproterenol was applied using a robotic dispensing machine, and the resulting changes in spike rate and duration were compared with results gained by experiments with a large scale MEA chip. The experimental findings inspired the development of a technology platform that was finally evaluated by monitoring extracellular signals from myocytes in response to Isoproterenol. Another topic was the comparison of cell-substrate interaction monitored on various electrode structures.
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Drushel, Richard Frederick. "Anatomical and extracellular matrix development of embryonic chick leg muscle in vivo and in vitro." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1060365796.
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Reisbig, Nathalie A. "Synovial Extracellular Matrix and Synovial Mesenchymal Stem Cells are Chondrogenic In Vitro and In Vivo." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543150403002824.
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Bieber, Stéphanie [Verfasser], and Markus [Akademischer Betreuer] Sperandio. "The role of extracellular MRP8/14 in leukocyte recruitment in vivo / Stéphanie Bieber ; Betreuer: Markus Sperandio." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1228787271/34.
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Ziebro, Thomas R. "In vivo PPy(DBS) sensors to quantify excitability of cells via sodium fluctuations in extracellular solution." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492031927557033.
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Hiratsuka, Toru. "Intercellular propagation of extracellular signal-regulated kinase activation revealed by in vivo imaging of mouse skin." Kyoto University, 2015. http://hdl.handle.net/2433/199209.
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Annecchino, Luca. "Development and validation of a robotic two-photon targeted whole-cell recording system for in vivo electrophysiology." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/56991.
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Understanding the functional principles of the mammalian cortical circuit is a major challenge in neuroscience. To make progress towards this understanding, one needs to be able to assess the behavioural dynamics of individual neuronal elements of this circuit. Manual whole-cell recording (WCR) in vivo is recognised as the “gold standard” method for electrophysiological interrogation of individual neurons. It allows subthreshold and suprathreshold signals to be recorded, perturbations to be applied through current injection, and DNA vectors to be directly delivered into the patched cells as part of the pipette internal solution. Unfortunately, the WCR technique for in vivo application is a “blind” procedure and has a low-throughput. In addition, the genetic and morphological identity of the recorded neuron often cannot be accounted for. The inherent cell-type non selectivity of this technique can be overcome by combining WCR with two-photon laser scanning microscopy, and targeting recordings to specifically labelled individual cells or cell classes. Targeted electrophysiological interrogation allows one to examine the properties of both single cells and neuronal assemblies and, additionally, the role of cell type-specific proteins in orchestrating neuronal responses. Targeted recordings in vivo may enable to test a wide range of hypotheses related to information processing in the cortical circuits. However, probing and studying the properties of individual cells in live animal preparations remains a challenge in neuroscience. In particular, precise vision-guided control of patch pipette motion and viewpoint generation of microscope objective for targeted single-cell electrophysiological interrogation is problematic. It requires specialised skills acquired through extensive practice and training by individual operators. Although automatic patch clamp technology has been in use for some years exclusively for cell culture-based paradigms, only recently has Kodandaramaiah et al. demonstrated a “blind” automated patch clamp system for in vivo recordings. However, a fully automatic method for in vivo WCR targeting specific cells or cell-types has not been implemented in any robotic system so far. In this study an automated two-photon targeted whole-cell patch clamping algorithm is demonstrated as a workable solution. The aim of this work was to develop a robotic integrated targeted autopatcher that minimised labour intensive procedures and increased the throughput both in blind and two-photon targeted WCR in live animals. The system automatically controls a micromanipulator, a microelectrode signal amplifier a two-photon microscope and a custom made regulator for controlling the internal pressure of the pipette. The two-photon microscope acquires images of fluorescently labelled cells, and cell-targets for patch clamp are selected via a point-and-click graphical user interface. Optical coordinates are initially converted to the micromanipulator coordinate system and a suitable path calculated to guide the patch pipette towards the target. This platform allows to compensate for brain tissue deformation and subsequent neuronal target movement caused by pipette insertion. As proof-of-concept, the system was tested in both “blind” and two-photon targeted paradigms and achieved performances comparable to human operators, in terms of yield, recording quality and operational speed. Hit rate for “blind” WCR was 51.4% (n=18, 35 attempts across 5 mice). RITA was also calibrated and tested for targeting specific cell types in the cortex of intact mouse brain labelled via fluorescent dye loading (e.g. Oregon Green BAPTA-1 and/or Sulforhodamine 101). Pipettes were automatically guided to the target cells and recordings obtained from visually identified neurons as well as astrocytes. These results prove the feasibility of robotic targeted WCR patch clamp in vivo and establish this system as a powerful tool for automated electrophysiological experiments in the brain.
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Ahn, Jeong H. Lee Myeongwoo. "The functional analysis of NPXY motif in [beta] integrin in vivo." Waco, Tex. : Baylor University, 2008. http://hdl.handle.net/2104/5275.
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Czerniecki, Stefan. "In vivo investigation of talin, tensin, and integrin-linked kinase dynamics at stable cell-extracellular matrix adhesions." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44285.
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Cell-extra cellular matrix (ECM) adhesion through the integrin family of receptors is required for metazoan development, and throughout adult life. Elucidating the mechanisms that regulate this adhesion is fundamental to understanding how animals create and maintain tissue architecture. Modulating adhesion assembly and disassembly is one of the key ways in which adhesion strength and integrity is regulated. We concentrate on analyzing the dynamics of three important components of the integrin adhesion complex (IAC), talin, tensin, and ILK, to determine how they function as mechano-sensory components of cell-ECM adhesions in the context of a living, multicellular organism, Drosophila melanogaster. We utilize fluorescently-tagged proteins under conditions of altered mechanical force, combined with a specialized fluorescence recovery after photobleaching (FRAP) protocol, to examine the dynamics of talin, tensin, and ILK. We subsequently use advanced mathematical modeling to gain mechanistic insight into how protein turnover is modified by tensile force. Furthermore, we attempt to clarify the role of key talin domains in mechanosensation, using FRAP and Drosophila homologs of previously characterized talin mutations, under conditions of altered force. The results outlined in this work show that talin mobility is directly regulated by force in an intact, complex organism at sites of stable adhesion between integrins and the ECM. Moreover, the results indicate that the mobility change due to increased force is a robust process, and not easily disrupted by mutating talin domains. Changes in talin dynamics when force is reduced is an active process, and is dependent on both the physical linkage of talin to integrin, and the ability of talin to auto-inhibit. Furthermore, studies of talin, tensin, and ILK turnover with high-temporal resolution uncover the intricacies of adhesion regulation in response to changing environmental conditions, with talin primarily regulated on the level of recycling, tensin regulated by a mix of both recycling and binding, and ILK regulated through control of binding.
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Somerville, Margaret. "The action of extracellular products from Pseudomonas aeruginosa on airway mucus secretion in vivo and in vitro." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241369.
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Cao, Yi. "Investigation of expression of extracellular matrix component genes during tendon healing process an in vivo chicken study /." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42182414.
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Damen, Angela N. "In vivo Characterization Of Non-Myocyte Heterogeneity During The Postnatal Development Of The Cardiac Interstitium." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1415625809.
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Lau, Petrina Yau Pok. "Long-term plasticity of excitatory inputs onto identified hippocampal neurons in the anaesthetized rat." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:172e0d36-0d67-4932-962e-9ee08dcc366c.
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Use-dependent long-term plasticity in synaptic connections represents the cellular substrate for learning and memory. The hippocampus is the most thoroughly investigated brain area for long-term synaptic plasticity, long-term potentiation (LTP) and long-term depression (LTD) are both well characterized in glutamatergic excitatory connections between hippocampal principal cells in vitro and in vivo. An increasing number of studies based on acute brain slice preparations report LTP and LTD in excitatory synapses onto postsynaptic hippocampal GABAergic inhibitory interneurons. However, a systematic study of activity-induced long-term plasticity in excitatory synaptic connections to inhibitory GABAergic interneurons in vivo is missing. To determine whether LTP and LTD occur in excitatory synaptic connections to the hippocampal CA1 area GABAergic interneurons types in intact brain, I have used juxtacellular recording to measure synaptically evoked short-delay postsynaptic action potential probability in identified CA1 neurons in the urethane-anaesthetized rats. Plasticity in excitatory synaptic connections to CA1 cell types was measured as a change of afferent pathway stimulation-evoked postsynaptic spike probability and delay. In the study only experiments with monosynaptic-like short-delay (range 3-12 ms) postsynaptic spikes phase-locked to afferent stimulation were used. Afferent fibres were stimulated from the CA1 area of the hippocampus at the contralateral (left) side to avoid simultaneous monosynaptic activation of GABAergic fibres and to exclude antidromic spikes in recorded CA1 cells (in right hemisphere). Plasticity in pathways was tested using theta-burst high-frequency stimulation (TBS, 100 pulses), which is one of the most common synaptic plasticity induction protocols in acute brain slice studies. I discovered that TBS elicited permanent potentiation in single shock-evoked postsynaptic spike probability with shortening or no change in evoked spike latency in various postsynaptic neuron types including three identified pyramidal cells and parvalbumin-expressing (PV+) interneurons. Most fast-spiking PV+ cells showed LTP including an axo-axonic cell and one bistratified cell, whereas two identified basket cells exhibited LTD in similar experimental conditions. In addition, I discovered diverse plasticity in non-fast spiking interneurons, reporting LTP in an ivy cell, and LTD in three incompletely identified regular-spiking CA1 interneurons. I report that the underlying brain state, defined as theta oscillation (3-6 Hz) or non-theta in local field potential, failed to explain whether LTP, LTD or no plasticity was generated in interneurons. The results show that activity-induced potentiation and depression similar to LTP and LTD also occur in excitatory synaptic pathways to various CA1 interneurons types in vivo. I propose that long-term plasticity in excitatory connections to inhibitory interneurons may be take place in learning and memory processes in the hippocampus.
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Rünker, Annette E. "Mutations in the extracellular domain of the neural cell adhesion molecule L1 impair protein trafficking in vitro and in vivo." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965753778.
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Tiwari, Ekta. "ASSESSMENT OF CANINE BLADDER FUNCTION RESTORATION USING BEHAVIORAL MONITORING AND IN-VIVO ELECTROPHYSIOLOGICAL TECHNIQUES." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/590674.
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Electrical and Computer EngineeringPh.D.
Spinal cord injuries and other neurological disorders can disturb the regulation of normal bladder function including continence and micturition. Developing new neuronal pathways by surgically rerouting nerves is a potential approach for restoring bladder function. Our laboratory successfully rerouted somatic nerves to the anterior vesical branch of the pelvic nerve to reinnervate the bladder muscle in canines. Electrical stimulation of these transferred nerves induced detrusor pressure and bladder emptying and we confirmed regrowth of these rerouted nerves using retrograde neurotracing methods. In these studies, reinnervation was proved at 1st and 3rd months after decentralization. We believe that our aim of developing an approach to surgically reinnervate the bladder after long-term decentralization is critical to the success of the reinnervation surgery due to the possibility that patients would delay having a surgery until they try other non-surgical approaches or therapies. We also demonstrated the reinnervation of urethral and anal sphincters by femoral to pudendal nerve transfer after sacral ventral root transection to restore continence. However, these studies did not demonstrate the reinnervation of bladder, urethra and anal sphincter, all in same animal that would be helpful to human patients with lower motor neuron lesioned bladders to restore both continence and emptying. Therefore, prior to applying these surgical procedures to human patients, further investigation is required to prove the effectiveness of nerve transfer strategies in this canine model using multiple experimental techniques. This dissertation is a part of a larger project in canines examining whether surgical rerouting of obturator to pelvic nerve and sciatic to pudendal nerve allows restoration of bladder, urethral and anal sphincter functions, including continence (storage) and emptying (voiding and defecation) functions, in lower motor neuron lesioned bladders. In this study, it was aimed to explore bladder and urethral reinnervation using behavioral observation and in-vivo electrophysiological techniques. In order to completely prove that the reinnervation surgeries are responsible for restoration of bladder and urethral functions, it was first necessary to demonstrate the absence of these functions in animals with long term decentralized bladders and to determine whether the same animals were able to recover functions after reinnervation. In specific aim 1, we addressed this goal by tracking squat-and-void behaviors at monthly intervals after decentralization and reinnervation, using home cage video recordings and evaluation of bladder sensation and emptying after bladder filling. Immediately prior to euthanasia, reinnervation was also explored by electrical stimulation of transferred nerves to evaluate motor function. Retrograde neuronal tracing was also performed to explore sensory reinnervation. Results showed evidence of functional restoration of bladder and urethral function in reinnervated animals based on behavior observation and electrical stimulation of transferred nerves. Also, regrowth of neuronal cells in the new neuronal pathways was observed that were developed by the nerve transfer surgeries. This study also aimed to establish an electroneurogram recording method (part of in-vivo electrophysiological experiments) to explore afferent (sensory) neuronal activity in transferred nerves induced by bladder filling. However, the extraction of neuronal activity from the peripheral nerves is a challenging task. Several factors including noise, interference from surrounding muscle activities and the electronic components can affect these microvolts level recordings. Choice of recording electrode in configuration with the whole recording setup also plays a significant role while performing these low amplitude signal recordings. In specific aim 2, we addressed this issue by refining electroneurogram recording techniques to obtain high strength signal during multifiber recording. We first developed custom electrodes, suitable for varying nerve diameters and available implantation sites, were tested for functionality. Then, we performed multiple testing using these electrodes with different amplifiers to calibrate noise in saline. Testing results helped to establish the recording setup suitable for in-vivo experimental environment. Later, these refined techniques were applied to record afferent (sensory) activity of sciatic nerves and afferent (sensory) and efferent (motor) activity of hypogastric nerves in rats. Based on the recording results, it was aimed to employ similar techniques in order to record nerve activity in the canine model. Prior to applying these refined techniques to explore sensory reinnervation from new neuronal pathways after nerve transfer surgeries, in specific aim 3, we aimed to assess the hypogastric nerve activity in normal intact and acutely lumbosacral decentralized bladders using these refined techniques. The effects of electrical stimulation of hypogastric nerves or lumbar roots on detrusor pressure were determined, as were effects of isoflurane versus propofol anesthetics on hypogastric nerve stimulation evoked pressure. Hypogastric nerve activity was recorded using custom-made bipolar cuff electrodes during bladder filling. To confirm or refute that any increase in electroneurogram during bladder filling is due to afferent activity from the end organ, the hypogastric nerve was transected between the recording electrode and the spinal cord and the effects of bladder filling on afferent but not efferent activity were recorded. Results showed that electrical stimulation of hypogastric nerves evoked low amplitude detrusor pressures that did not differ between the two anesthetics. Upper lumbar (L2) ventral root stimulation evoked detrusor pressures were suppressed, yet not eliminated after transection of hypogastric nerves and all spinal roots below L5. Afferent and efferent hypogastric nerve activity did not change with bladder filling in neuronally intact bladders but decreased in decentralized bladders. No change in afferent activity were observed during bladder filling in normal intact and decentralized bladders. Overall findings in this research indicate that the new neuronal pathways created by nerve transfer can restore bladder sensation and emptying function in lower motor neuron-lesioned canines. A more complete decentralized bladder model needs to include transection of both the lumbosacral spinal roots innervating the bladder and the hypogastric nerves prior to performing nerve transfer surgeries. The refined electroneurogram recording methods may be suitable for evaluating the effectiveness of nerve transfer surgeries by monitoring the sensory activities of the transferred nerve.
Temple University--Theses
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Tan, J. J. "Cardiosphere-derived stem cell culture, characterisation and labelling for in vivo testing in the infarcted heart." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:d902b4f4-6e32-45dd-9767-8e0a17967393.
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Cardiac stem cells (CSCs), isolated from heart tissue explants and expanded via the formation of cardiospheres (Csp), are a promising candidate for cell therapy to prevent heart failure following myocardial infarction. To allow early administration to patients, isolation and expansion of CSCs must be performed in the shortest time possible. Hence, this project aimed to optimize culture conditions and characterize the cardiac explant-derived cells (EDCs), Csp and Csp-derived cells (CDCs) produced. Rat neonatal EDCs contained 4-7% c-kit+ cells, measured using flow cytometry. Optimal Csp growth conditions were determined, such that plating 3 x 10^4 EDCs per well of a 24-well plate coated with 16.7 µg/ml poly-D-lysine, in CGM containing 7% serum, improved Csp production and generated 1.5 x 10^7 CDCs in 16 days, a sufficient number for cell therapy. The CDCs expressed the stemness markers; c-kit, Oct3/4, SOX2, and Klf-4, and the cardiac differentiation markers; GATA4 and Nkx2.5. The therapeutic effect of CDCs may be limited by the low, 3 ± 0.1%, c-kit+ cell numbers. To increase c-kit+ cells in CDCs, an alternate culture method for Csp and different extracellular matrices (ECM) for cell expansion were tested. The hanging drop culture method produced Csp with higher levels of c-kit+ cells (9 ± 2%) than poly-D-lysine-coated and low-bind culture dishes. Of five ECM tested, collagen IV was found to enhance EDC migration and CDC proliferation, and produced 11 ± 0.4% c-kit+ cells, with Csp cultured in hanging drops. Intramyocardial injection of CDCs improved left ventricular ejection fractions of infarcted rat hearts by 9% and prevented the peri-infarct wall from thinning, measured in vivo using MRI over 16 weeks. To improve cell tracking using MRI, two MR positive contrast agents, gadolinium-DTPA and gadonanotubes were tested. Gd-DTPA had low sensitivity after labelling (1.4 x 10^5 cells/mm2); whereas gadonanotubes did not provide positive contrast at 11.7 T. Thus, neither contrast agent could be used for cell tracking using high magnetic field. In conclusion, CDCs were an effective source of stem cells that could be used for heart repair, although cells could not be tracked using positive MR contrast.
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Halpern, Jeffrey Mark. "Non-Planar Diamond Electrodes for Biomedical Neural Sensing and Stimulating." Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1269612139.
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Thesis (Doctor of Philosophy)--Case Western Reserve University, 2010Department of Chemical Engineering Title from PDF (viewed on 2010-05-25) Includes abstract Includes bibliographical references and appendices Available online via the OhioLINK ETD Center
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Pospischil, Martin. "Interaction between synaptic conductances and action potential initiation in cortical neurons : computational models and analysis of intracellular recording." Paris 6, 2007. http://www.theses.fr/2007PA066647.
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Pendants les etats naturels d'activite in vivo, les neurones neocorticaux sont sujets a une conductance membranaire forte et fluctuante. Cependant, les proprietes integratives des neurones ne sont pas connues pendant ces etats de "haute conductance" (HC). Nous avons (1) caracterise le lien entre la dynamique des conductances et l'initiation du potentiel d'action (PA) dans les neurones corticaux dans les etats HC; (2) compare differents modeles de reponse de PA (PSTH) pendant ces etats. Nous distinguons deux modes de decharge, selon que le PA est evoque par une augmentation d'excitation ou par une diminution d'inhibition. Nous avons propose une nouvelle methode pour calculer les "spike-triggered average" (STA) des conductances a partir du potentiel membranaire, teste cette methode numeriquement et in vitro, ainsi que applique cette methode aux enregistrements in vivo. Nous demontrons que les PAs inhibiteurs sont majoritaires chez le chat eveille, ce qui revele un role majeur de l'inhibition
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Stridh, Sara. "Regulation of Renal Hyaluronan in Water Handling : Studies in vivo and in vitro." Doctoral thesis, Uppsala universitet, Integrativ Fysiologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-209763.
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Hyaluronan (HA) is a negatively charged extracellular matrix (ECM) component with water-attracting properties. It is the dominating ECM component in the renal medullary interstitium, where the amount changes in relation to hydration status: it increases during hydration and decreases during dehydration. It has, therefore, been suggested that HA participates in the regulation of renal fluid handling by changing the permeability properties of the interstitial space. This thesis investigates potential mechanisms for such a role in renal fluid regulation. The results demonstrate that the high renal HA content of late nephrogenesis decreases during the completion of kidney development in the rat, which takes place in the neonatal period. The heterogenous distribution of HA is mainly established during the first three weeks after birth. On day 21, the HA content is similar to that in the adult rat. The process is dependent on normal Ang II function. It primarily involves a reduction of HA synthase 2 expression and an increase of medullary hyaluronidase 1. The cortical accumulation of HA that results from neonatal ACE inhibition can partly explain the pathological condition of the adult kidney, which causes reduced urinary concentration ability and tubulointerstitial inflammation. It is possible to reduce renomedullary HA with the HA synthesis inhibitor 4-MU, and the kidney’s ability to respond to a hydration challenge will then be suppressed, without affecting GFR. The investigation of renomedullary interstitial cells (RMIC) in culture, shows that media osmolality and hormones of central importance for body fluid homeostasis, such as angiotensin II, ADH and endothelin, affect HA turnover through their effect on the RMICs, in a manner comparable to that found in vivo during changes in hydration status. In established streptozotocin-induced diabetes, HA is regionally accumulated in the kidney, proteinuria and polyuria, reduced urine osmolality, and reduced response to ADH V2 activation will occur. As opposed to the proteinuria, the HA accumulation is not sensitive to mTOR inhibition, suggesting an alternate pathway compared to other ECM components Taken together, the data suggest that during normal physiological conditions, renomedullary interstitial HA participates in renal fluid handling by affecting the interstitial prerequisites for fluid flux across the interstitial space. This is possible due to the water-attracting and physicochemical properties of this glycosaminoglycan. During pathological conditions, such as diabetes, the elevated interstitial HA can contribute to the defective kidney function, due to the proinflammatory and water-attracting properties of HA.
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Castagnola, Valentina. "Implantable microelectrodes on soft substrate with nanostructured active surface for stimulation and recording of brain activities." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2646/.
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Les prothèses neuronales implantables offrent de nos jours une réelle opportunité pour restaurer des fonctions perdues par des patients atteints de lésions cérébrales ou de la moelle épinière, en associant un canal non-musculaire au cerveau ce qui permet la connexion de machines au système nerveux. La fiabilité sur le long terme de ces dispositifs, se présentant sous la forme d'électrodes implantables, est un facteur crucial pour envisager des applications dans le domaine des interfaces cerveau-machine. Cependant, les électrodes actuelles pour l'enregistrement et la stimulation se détériorent en quelques mois voire quelques semaines. Ce défaut de fiabilité sur le long terme, principalement lié à une réaction chronique contre un corps étranger, est induit au départ par le traumatisme consécutif à l'insertion du dispositif et s'aggrave ensuite, durant les mouvements du cerveau, à cause des propriétés mécaniques inadaptées de l'électrode par rapport à celles du tissu. Au cours du temps, l'ensemble de ces facteurs inflammatoires conduit à l'encapsulation de l'électrode par une couche isolante de cellules réactives détériorant ainsi la qualité de l'interface entre le dispositif implanté et le tissu cérébral. Pour s'affranchir de ce phénomène, la biocompatibilité des matériaux et des procédés, ainsi que les propriétés mécaniques de l'électrode doivent être pris en considération. Durant cette thèse, nous avons abordé la question en développant un procédé de fabrication simple pour réaliser des dispositifs implantables souples en parylène. Les électrodes flexibles ainsi obtenues sont totalement biocompatibles et leur compliance est adaptée à celle du tissu cérébral ce qui limite fortement la réaction inflammatoire occasionnée par les mouvements du cerveau. Après avoir optimisé le procédé de fabrication, nous avons focalisé notre étude sur les performances du dispositif et sa stabilité. L'utilisation d'une grande densité d'électrodes micrométriques, avec un diamètre de 10 à 50 µm, permet de localiser les zones d'enregistrement en rendant possible, par exemple, la conversion d'un ensemble de signaux électrophysiologiques en une commande de mouvement. En contrepartie, la réduction de la taille des électrodes conduit à une augmentation de l'impédance ce qui dégrade la qualité d'enregistrement des signaux. Ici, un polymère conducteur organique, le poly(3,4-ethylenedioxythiophene), PEDOT, a été utilisé pour améliorer les caractéristiques électriques d'enregistrement d'électrodes de petites dimensions. Le PEDOT a été déposé sur la surface des électrodes par électrochimie avec une grande reproductibilité. Des dépôts homogènes avec des conductivités électriques très élevées ont été obtenus en utilisant différents procédés électrochimiques. Grâce à l'augmentation du rapport surface/volume induit par la présence de la couche de PEDOT, une diminution significative de l'impédance de l'électrode (jusqu'à 3 ordres de grandeur) a été obtenue sur une large plage de fréquences. De tests de vieillissement thermique accéléré ont également été effectués sans influence notable sur les propriétés électriques démontrant ainsi la stabilité de la couche de PEDOT durant plusieurs mois. Les dispositifs ainsi obtenus, fabriqués en parylène avec un dépôt de PEDOT sur la surface active des électrodes, ont été testés in vitro et in vivo sur des cerveaux de souris. Un meilleur rapport signal sur bruit a été mesuré durant des enregistrements neuronaux en comparaison avec des résultats obtenus avec des électrodes commerciales. En conclusion, la technologie décrite ici, associant stabilité sur le long terme et faible impédance, a permis d'obtenir des électrodes implantables parfaitement adaptées pour le développement d'interfaces neuronales chroniquesImplantable neural prosthetics devices offer, nowadays, a promising opportunity for the restoration of lost functions in patients affected by brain or spinal cord injury, by providing the brain with a non-muscular channel able to link machines to the nervous system. The long term reliability of these devices constituted by implantable electrodes has emerged as a crucial factor in view of the application in the "brain-machine interface" domain. However, current electrodes for recording or stimulation still fail within months or even weeks. This lack of long-term reliability, mainly related to the chronic foreign body reaction, is induced, at the beginning, by insertion trauma, and then exacerbated as a result of mechanical mismatch between the electrode and the tissue during brain motion. All these inflammatory factors lead, over the time, to the encapsulation of the electrode by an insulating layer of reactive cells thus impacting the quality of the interface between the implanted device and the brain tissue. To overcome this phenomenon, both the biocompatibility of materials and processes, and the mechanical properties of the electrodes have to be considered. During this PhD, we have addressed both issues by developing a simple process to fabricate soft implantable devices fully made of parylene. The resulting flexible electrodes are fully biocompatible and more compliant with the brain tissue thus limiting the inflammatory reaction during brain motions. Once the fabrication process has been completed, our study has been focused on the device performances and stability. The use of high density micrometer electrodes with a diameter ranging from 10 to 50 µm, on one hand, provides more localized recordings and allows converting a series of electrophysiological signals into, for instance, a movement command. On the other hand, as the electrode dimensions decrease, the impedance increases affecting the quality of signal recordings. Here, an organic conductive polymer, the poly(3,4-ethylenedioxythiophene), PEDOT, has been used to improve the recording characteristics of small electrodes. PEDOT was deposited on electrode surfaces by electrochemical deposition with a high reproducibility. Homogeneous coatings with a high electrical conductivity were obtained using various electrochemical routes. Thanks to the increase of the surface to volume ratio provided by the PEDOT coating, a significant lowering of the electrode impedance (up to 3 orders of magnitude) has been obtained over a wide range of frequencies. Thermal accelerated ageing tests were also performed without any significant impact on the electrical properties demonstrating the stability of the PEDOT coatings over several months. The resulting devices, made of parylene with a PEDOT coating on the active surface of electrodes, have been tested in vitro and in vivo in mice brain. An improved signal to noise ratio during neural recording has been measured in comparison to results obtained with commercially available electrodes. In conclusion, the technology described here, combining long-term stability and low impedance, make these implantable electrodes suitable candidates for the development of chronic neural interfaces
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Di, Summa Pietro Giovanni. "Schwann cell-like differentiated adipose-derived stem cells : in vivo applications and future perspectives for nerve regeneration." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/schwann-celllike-differentiatedadiposederived-stem-cellsin-vivo-applications-and-futureperspectives-for-nerve-regeneration(cce4ab09-f58b-48c6-9372-5efcb1127e1a).html.
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Traumatic injuries resulting in peripheral nerve lesions often require a graft to bridge the gap. Although autologous nerve graft is still the first choice strategy in reconstructions, it has the severe disadvantage of the sacrifice of a functional nerve. Cell transplantation in a bioartificial conduit is an alternative strategy to create a favourable environment for nerve regeneration. Among adult stem cells, adipose-derived stem cells (ASC) are a useful tool in regenerative medicine as they can be induced towards multiple mesodermal and nonmesodermal lineages, being recently differentiated into cells showing Schwann cell-like morphology, glial cell markers and increased neurotrophic potential. The first two chapters of this work describe in vivo applications of Schwann cell-like differentiated ASC (dASC), seeded into biodegradable nerve guides made of fibrin, investigating both brief (2 weeks) and long (4 months) term effects on the regenerating nerves. Comparison was carried out with similarly differentiated bone marrow mesenchymal stem cells (dMSC), Schwann cells (SC)and empty fibrin conduits, as well as with autologous nerve grafts. Regeneration was evaluated in a 1cm gap total axotomy sciatic nerve injury model on rats. Results showed that dASC could improve regeneration distance in a similar manner to other regenerative cells inthe brief term. This effect was maintained and strengthened in the long term, where nerve morphology, spinal motoneurons regeneration, protection from muscle atrophy and electrophysiological performances of regenerated nerves were analysed. dASC positive effects lasted in the long term with functional results comparable to the autologous nerve grafts, which served as controls. The third chapter focuses on the possibility to further improve dASC regenerative performances using fibronectin and laminin, two key extracellular matrix (ECM) molecules involved in nerve regeneration, with the future aim to optimize cell host, directional cues and neurotrophism of tissue engineered conduits. Fibronectin and laminin protected dASC from stress-induced cell death in vitro, significantly increasing cell adhesion and viability. Laminin significantly improved neurotrophic properties of dASC enhancing neurite outgrowth of both primary sensory neurons and NG108-15 neurons co-cultured with dASC, suggesting a further activation of the neurotrophic effect of dASC by ECM molecules. These improved effects were increased when a direct contact was established between the laminin substrate, dASC and neurons, suggesting a primary role of laminin in contact signalling, finally boosting the neurotrophic potential of dASC. Further studies will be needed to clarify the interactions between dASC and the complexniche of peripheral nerve regeneration, including the ECM molecules. However, the neurotrophic potential of dASC expressed in both in vitro and in vivo experiments opens wide perspectives in tissue engineering applications among new methods to enhance peripheral nerve repair.
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Watanabe, Moe, Yuki Sugiura, Eiji Sugiyama, Michiko Narita, Edita Navratilova, Takashige Kondo, Naohiko Uchiyama, et al. "Extracellular N-acetylaspartylglutamate released in the nucleus accumbens modulates the pain sensation: Analysis using a microdialysis/mass spectrometry integrated system." SAGE PUBLICATIONS INC, 2018. http://hdl.handle.net/10150/627130.
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Various small molecules act as neurotransmitters and orchestrate neural communication. Growing evidence suggests that not only classical neurotransmitters but also several small molecules, including amino acid derivatives, modulate synaptic transmission. As conditions of acute and chronic pain alter neuronal excitability in the nucleus accumbens, we hypothesized that small molecules released in the nucleus accumbens might play important roles in modulating the pain sensation. However, it is not easy to identify possible pain modulators owing to the absence of a method for comprehensively measuring extracellular small molecules in the brain. In this study, through the use of an emerging metabolomics technique, namely ion chromatography coupled with high-resolution mass spectrometry, we simultaneously analyzed the dynamics of more than 60 small molecules in brain fluids collected by microdialysis, under both the application of pain stimuli and the administration of analgesics. We identified N-acetylaspartylglutamate as a potential pain modulator that is endogenously released in the nucleus accumbens. Infusion of N-acetylaspartylglutamate into the nucleus accumbens significantly attenuated the pain induced by the activation of sensory nerves through optical stimulation. These findings suggest that N-acetylaspartylglutamate released in the nucleus accumbens could modulate pain sensation.
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Konduri, Suchitra. "The Influence of normal physiological forces on porcine aortic heart valves in a sterile ex-vivo pulsatile organ culture system." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-03042005-135623/unrestricted/konduri%5Fsuchitra%5F200505%5Fmast.pdf.
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Thesis (M. S.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2005.Dr. Athanassios Sambanis, Committee Member ; Dr. Timothy M. Wick, Committee Member ; Dr. Ajit P.Yoganathan, Committee Chair. Includes bibliographical references.
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Joyce, Belinda Jane. "Elastin synthesis in the fetal sheep lung in vivo : effects of physical, metabolic and endocrine factors." Monash University, Dept. of Physiology, 2004. http://arrow.monash.edu.au/hdl/1959.1/5263.
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Cisterna, Ambart Ester Covarrubias. "Análise da ação do embrião e dos hormônios ovarianos na regulação da matriz extracelular de células deciduais: estudo in vivo e in vitro." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/42/42134/tde-24052014-084021/.
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Durante a gestação, em varias espécies de mamíferos, os fibroblastos endometriais são alvos de profundas modificações morfofuncionais que levam a aquisição de um fenótipo epitelial e à expressão de novas moléculas, formando uma nova estrutura no útero denominada decídua. Em camundongos, a reação decidual pode ser estimulada artificialmente (na ausência de embrião), resultando na formação do deciduoma, um modelo de grande relevância para a identificação de fatores oriundos ou não do embrião necessários para a promoção da decidualização. A decidualização também promove uma profunda remodelação da matriz extracelular (MEC) do endométrio, e ambos os processo são fundamentais para o sucesso da gestação. Existem evidencias, muitas das quais são oriundas dos estudos do Laboratório de Biologia da Reprodução e Matriz extracelular (LBR-MEC), mostrando que a remodelação da MEC do útero não grávido é modulada pelos hormônios ovarianos estrógeno (E2) e progesterona (P4). Faltam, entretanto, na literatura, estudos consistentes sobre a regulação da MEC endometrial na ausência de sinais parácrinos provenientes do embrião. Além disso, não se conhece detalhes sobre a ação dos hormônios ovarianos sobre a produção de componentes da MEC por células deciduais. Nesse contexto, o presente estudo teve dois objetivos centrais: (i) caracterizar por imuno-histoquímica a composição e organização da MEC durante o desenvolvimento do deciduoma, (ii) estudar por qPCR, Western blot, e imunolocalização o efeito dos hormônios E2 e Medroxiprogesterona (MPA) na dinâmica da expressão de RNAm, síntese e secreção de moléculas da MEC em culturas primárias de células obtidas de deciduoma. Observamos que, a distribuição do colágeno tipo I, III, IV, V e dos proteoglicanos decorim, biglicam e versicam no deciduoma, foi semelhante ao já observado na decídua. As análises in vitro, mostram que o hormônio E2 aumenta a expressão gênica, a síntese e a deposição de decorim enquanto o MPA tem como alvo o biglicam. Ambos hormônios modulam a expressão de desmina, um marcador de decidualização. O presente estudo também mostra que o padrão de remodelação das moléculas alvo do presente estudo, é similar ao observado durante a decidualização da gestação normal, Conclui-se, portanto, que a remodelação da MEC é um evento intrínseco do processo de decidualização quer na gestação quer na pseudogestação. Ou seja, não foram identificadas diferenças que indicassem a existência de controle pelo embrião. Mostramos ainda que, in vitro, os hormônios E2 e MPA regulam de modo específico a expressão gênica e a secreção do proteoglicanos decorim e biglicam.During pregnancy in several species of mammals, including humans and mice, endometrial fibroblasts undergo extensive morphofunctional changes acquiring an epithelial phenotype. Those new cells form a new structure in the uterus called decidua. In mice, the decidual reaction can be artificially induced in pseudopregnant females resulting in the formation of a structure morphologically similar to the decidua called deciduoma, a relevant model to study the putative role of the embryo upon decidualization. Endometrial decidualization is an essential event for the success of pregnancy. A notable remodeling of the extracellular matrix (ECM) organization and molecular composition occurs during this process. There are evidences, many of them coming from studies of the Laboratory of Reproductive and Extracellular Matrix Biology (LBR-MEC), that estrogen (E2) and progesterone (P4) modulate the remodeling of the uterine ECM. Nevertheless, there is no consistent information about the role, if it exists, of the embryo on the regulation of the endometrial ECM. Furthermore, it was not yet clarified how the ovarian hormones act on the production of ECM components by decidual cells. Thus, the objective of present study was to identify the composition and organization of the ECM during the development of the mouse deciduoma; and to study by qPCR, Western blot and immunolocalization methods, the effect of hormones E2 and medroxiprogesterone (MPA) on synthesis and secretion of ECM molecules by primary cultures of mouse decidual cells obtained from deciduoma. We found that the distribution of collagen types I, III, IV, V and proteoglycans decorin, biglycan and versican in deciduoma, was similar to that previously observed in the decidua. The in vitro assays showed E2 increases the gene expression for the core protein of Decorin, while MPA increases the expression of the core protein of Biglycan. In addition, was observed that both hormones increase the expression of desmin a marker of decidualization. These results showed that in the endometrium of both pregnant and pseudopregnant animals ECM molecules such as collagens and proteoglycans are similarly modulated by ovarian hormones. At from the present study we may conclude that ECM remodeling is an intrinsic event that happens during decidualization modulated by E2 and MPA and this modualation independ of the presence of the embryo in the uterus. In adition we showed that in decidual cells in vitro the gene expression and the secretion of proteoglycans decorin and biglycan are differentially regulated by hormones E2 and MPA.
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Rodríguez, Salinas Roberto Javier. "El uso e impacto de las técnicas de grabación y mezcla analógica en la producción musical estadounidense de pop y rock (2011-2017): Alternativas para su aplicación en el estudio digital." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/654919.
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El presente trabajo de investigación trata de identificar y analizar la influencia y la aplicación del audio analógico en la producción musical contemporánea, abarcando diversos criterios: sonoro/técnico, de ejecución, social, de preservación o archivo, entre otros. A pesar de que el audio digital, y el uso derivado de las herramientas de edición y mezcla, se consideran el estándar en la industria musical actual, se conoce que un número importante de productores, ingenieros y artistas siguen empleando hoy en día las técnicas de grabación y mezcla analógica desarrolladas décadas atrás. Por ello, el audio analógico surge como una alternativa a los procesos de creación y producción musical modernos, tanto a nivel sonoro como de ejecución. Este trabajo parte del desarrollo técnico y estético en la grabación analógica, realizando comparaciones con su contraparte digital. Para ello, se toman en cuenta las opiniones y los procesos de producción de productores musicales y profesionales a cargo de las producciones discográficas más relevantes en los últimos años en el circuito norteamericano. Es en estas producciones donde se evidencia el uso creativo del audio analógico, así como su adaptación al entorno digital. Finalmente, se tiene en cuenta al productor independiente como principal beneficiario de esta publicación, quien conoce directa o indirectamente los beneficios del audio analógico, pero no necesariamente cuenta con los recursos para integrarlo a su estación de trabajo. Por ello, se busca brindar herramientas y soluciones para poder emplear e integrar las principales funciones del formato analógico y digital en una producción moderna.The hereby thesis attempts to identify and analyze the influence and application of analog audio in contemporary music production by covering diverse criteria: sonic/technical, performative, social, of preservation or archive, among others. Although digital audio, and its derived use of editing and mixing tools, are currently considered standard in the music industry, it is also known that a significant number of producers, engineers and artists still employ analog recording and mixing techniques developed decades ago. Hence, analog audio presents itself as an alternative to the modern creative and production processes, at both sonic and performance levels. This work begins with the technical and aesthetical development within an analog recording, comparing it afterwards with its digital counterpart. To serve this purpose, the opinion and detailed production processes of renowned American producers and professionals, responsible for the most acclaimed records in the last ten years, are taken into consideration. Those records evidence the creative use of analog audio, as well as its adaptation to a digital setup. Finally, independent producers could benefit the most from the information and arguments in this paper, because they directly or indirectly know the benefits of working analog, even when they often lack the resources to acquire these tools. Therefore, the author attempts to bring tools and solutions for the application of analog and digital audio in a single modern production.
Tesis
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Ghanavi, Parisa. "Effects of cartilage dust on cartilage formation in in vitro and in ectopic in vivo models." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/101499/1/Parisa_Ghanavi_Thesis.pdf.
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This thesis is a comparative study of cartilage tissue regeneration by the tissue’s resident cells with or without adding the tissue matrix’s particles, in the lab and followed by implantation in mouse. Incorporation of the particles with the cells appears to be a viable strategy to increase the cartilage-like matrix content in the short-term, and the particles appear to integrate into the regenerated tissue in the long-term.
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Pierucci, Amauri. "Influencia dos polimeros poli caprolactona (PCL) e poli L-acido latico (PLLA), sobre a expressão de componentes da membarna de celulas de Schwann in vitro e in vivo." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316490.
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Orientador: Alexandre Leite Rodrigues de OliveiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: A regeneração periférica é um fenômeno intrincado que envolve diferentes tipos celulares, dentre os quais as células de Schwann são os componentes celulares não neurais mais importantes. Após a lesão periférica, as células de Schwann proliferam e, juntamente com os macrófagos, participam na fagocitose dos fragmentos de mielina e dos axônios em degeneração. Essas auxiliam na orientação axonal em direção ao órgão alvo através da formação das bandas de Büngner. Ainda, atuam no rearranjo dos componentes da matriz extracelular do microambiente do nervo lesado, bem como na produção de vários fatores neurotróficos, entre eles, o fator neurotrófico do nervo (NGF), fator neurotrófico derivado do cérebro (BDNF), fator neurotrófico de crescimento ciliar (CNTF), visando à manutenção, desenvolvimento e regeneração dos neurônios após a lesão. As lesões nervosas que acometem no nervo periférico podem ser resultado de traumas como esmagamento, transecção parcial ou completa do nervo. Quando ocorre a transecção completa do nervo, há a perda de continuidade e forma-se uma fenda entre o coto proximal e o coto distal. No sentido de reparar-se o nervo lesionado, foram desenvolvidas diversas técnicas, incluindo-se o emprego de autoenxertos, próteses tubulares não absorvíveis e inertes (polietileno) e biorreabsorvíveis (biomateriais). Essas últimas têm a vantagem de sustentarem o inicio do processo regenerativo, orientando o brotamento axonal em direção ao coto distal, além de serem degradadas à medida que o nervo cresce em diâmetro. Podem ainda ser confeccionadas com as dimensões, formatos e porosidade desejados. Devido às características positivas destas próteses reabsorvíveis, a importância das células de Schwann e dos componentes da matriz extracelular, o presente trabalho tem como objetivos estudar a influência dos biomateriais poli L-ácido láctico e poli caprolactona sobre a expressão, pelas células de Schwann, das cadeias a1, a2 e ß1 que compõem as lamininas tipo I e II, bem como a expressão de colágeno tipo IV, através do emprego das técnicas de imunohistoquímica realizadas após a tubulização e imunocitoquímica através da cultura purificada de células de Schwann sobre os diferentes biomateriais. Além disso, avaliamos o comportamento das células de Schwann sobre os biomateriais, através da microscopia eletrônica de varredura. Já o resultado da regeneração axonal foi estudado através de uma análise morfológica pela microscopia de luz, microscopia eletrônica de transmissão e morfometria dos nervos regenerados. Comparando-se estruturalmente os tubos confeccionados pelo método de extrusão e solvente, pôde-se observar que o último apresentava espessura reduzida em comparação às próteses confeccionadas pelo método de extrusão. Ainda, a transparência dos tubos, ora propostos em nossa metodologia, influenciou positivamente durante o processo de implantação da prótese na tubulização. Após a regeneração, observou-se que o número de fibras regeneradas no interior dos tubos derivados das membranas de PCL foi significantemente maior, 30 e 60 dias após tubulização. Ainda, uma intensa marcação com S-100, colágeno tipo IV e laminina foi observada no nervo regenerado no interior das próteses, em cujos grupos utilizaram-se os biomaterias (PCL e PLLA). De fato, a imunomarcação demonstrou que os biomateriais e o microambiente no interior dos tubos foram capazes de estimular positivamente as células de Schwann em resposta à lesão nervosa periférica. Em conjunto, nossos resultados evidenciam que os tubos de PCL e PLLA derivados da membrana podem ser considerados um método alternativo na preparação de próteses tubulares visando o reparo do nervo periférico
Abstract: The present study proposed a new approach to produce tubular conduits designed for peripheral nerve repair. In this sense, membranes of PLLA and PCL were obtained after solvent evaporation and wrapped around a mandrel. The effectiveness of the nerve regeneration was compared with polyethylene and PCL extruded prosthesis 30 and 60 days after surgery. The comparison between extrusion and solvent tubes cleared shown structural differences which were directly proportional to the hardness and transparency. An important factor to be considered is that the fiber counting indicated that solvent PCL tubes provided a significantly greater number of axons 30 days after repair. Sixty days after operation, the greatest regenerative performance was obtained with PCL, regardless the method of construction of the tube. An intense labeling against S-100, type IV collagen and laminin could be observed in the tissue obtained from solvent PCL and PLLA groups, indicating that such constructions are able to positively stimulate Schwann cell responses. Overall, the present results provide evidence that solvent conduits may be regarded as an alternative preparation method for tubular prosthesis aiming peripheral nerve regeneration. In the in vitro study, PCL and PLLA solvent polymers were used for culturing purified of Schwann cells. The imunolabeling revealed an up-regularion of the expression of collagen IV, laminin I, laminin II and S-100 by the Schwann cells, showing that biodegradable polymers enhance the activity of such cells, positively influencing the peripheral nerve regeneration process
Doutorado
Anatomia
Mestre em Biologia Celular e Estrutural
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Chaudun, Fabrice. "Involvement of dorsomedial prefrontal projections pathways to the basolateral amygdala and ventrolateral periaqueductal grey matter in conditioned fear expression." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0118/document.
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A l’heure actuelle, une des principales questions des neurosciences comportementales est de comprendre les bases neurales des apprentissages et de comprendre comment des modifications au sein de circuits neuronaux spécifiques contrôlent les changements comportementaux liés à une expérience particulière. De nombreuses études ont récemment mis en évidence le rôle important des circuits neuronaux dans les phénomènes d’apprentissages associatifs, et notamment dans la régulation des comportements de peur. Cependant, leurs caractéristiques anatomiques et fonctionnelles restent encore largement inconnues. L’une des principales fonctions des circuits neuronaux est leur capacité à adapter le comportement en fonction de la nature des informations internes ou environnementales disponibles. Malgré de nombreux progrès réalisés sur la compréhension des substrats et mécanismes neuronaux sous tendant le conditionnement de peur au sein de structures telles que l'amygdale (AMG), le cortex préfrontal dorso-médian (dmPFC) et la substance grise periaqueducale (PAG), les mécanismes neuronaux gouvernant les interactions inter-structure ainsi que le contrôle local de ces différents circuits neuronaux restent encore largement inconnus. Dans ce contexte, ce travail de thèse a eupour objectifs principaux, d’évaluer la contribution des voies de projections dmPFC-BLA et dmPFC-vlPAG dans la régulation des comportements de peur, et, d’identifier les mécanismes neuronaux sous-jacent contrôlant l'expression de la peur. Afin de répondre à ces questions, nous avons utilisé conjointement des enregistrements électrophysiologiques unitaires et de potentiels de champs couplés à des approches optogénétiques au cours de l’expression de la peur conditionnée. Nous avons pu mettre en évidence un nouveau mécanisme neuronal basé sur une oscillation cérébrale à 4 Hz entre le dmPFC et le BLA impliqué dans la synchronisation neuronale des neurones de ces deux structures nécessaire à l’expression de la peur. Nous avons aussi démontré que le dmPFC via ses projections sur le vlPAG contrôle directement l’expression de la peur. Ensemble, nos données contribuent à une meilleure compréhension des circuits neuronaux ainsi que des mécanismes du comportement de peur qui dans le futur pourront aider à une amélioration thérapeutique des troubles anxieuxA central endeavour of modern neuroscience is to understand the neural basis of learningand how the selection of dedicated circuits modulates experience-dependent changes inbehaviour. Decades of research allowed a global understanding of the computations occurring inhard-wired networks during associative learning, in particular fear behaviour. However, brainfunctions are not only derived from hard-wired circuits, but also depend on modulation of circuitfunction. It is therefore realistic to consider that brain areas contain multiple potential circuitswhich selection is based on environmental context and internal state. Whereas the role of entirebrain areas such as the amygdala (AMG), the dorsal medial prefrontal cortex (dmPFC) or theperiaqueductal grey matter (PAG) in fear behaviour is reasonably well understood at themolecular and synaptic levels, there is a big gap in our knowledge of how fear behaviour iscontrolled at the level of defined circuits within these brain areas. More particularly, whereas thedmPFC densely project to both the basolateral amygdala (BLA) and PAG, the contributions ofthese two projections pathway during fear behaviour are largely unknown. Beside theinvolvement of these neuronal pathways in the transmission of fear related-information, theneuronal mechanisms involved in the encoding of fear behaviour within these pathways are alsovirtually unknown. In this context, the present thesis work had two main objectives. First,evaluate the contribution of the dmPFC-BLA and dmPFC-vlPAG pathways in the regulation offear behaviour, and second, identify the neuronal mechanisms controlling fear expression in thesecircuits. To achieve these goals, we used a combination of single unit and local field potentialrecordings coupled to optogenetic approaches in behaving animals submitted to a discriminativefear conditioning paradigm. Our results first, identified a novel neuronal mechanism of fear expression based on the development of 4 H oscillations within dmPFC-BLA circuits thatdetermine the dynamics of freezing behaviour and allows the long-range synchronization offiring activities to drive fear behaviour. Secondly, our results identified the precise circuitry at thelevel of the dmPFC and vlPAG that causally regulate fear behaviour. Together these data provideimportant insights into the neuronal circuits and mechanisms of fear behaviour. Ultimately thesefindings will eventually lead to a refinement of actual therapeutic strategies for pathological conditions such as anxiety disorders
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Ramos, Karina Lawrence. "Análise comparativa das distribuições espaciais de moléculas envolvidas na migração e invasão de um tumor cerebral de rato in vivo." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/42/42134/tde-30052008-123952/.
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O Glioblastoma multiforme (GBM) é o mais maligno tumor cerebral e apresenta uma alta capacidade proliferativa, invasiva e angiogênica. Neste estudo foi avaliada a distribuição espacial de moléculas envolvidas nesses processos num modelo de GBM de rato in vivo (C6). Por imunohistoquímicas observou-se que o tumor foi capaz de expressar diferentes elementos de matriz extracelular (colágenos I, III e IV, fibronectina, tenascinas C e R, vitronectina e proteoglicanos), moléculas de adesão (RHAMM, CD44 e integrinas) e a enzima proteolítica MMP-2. Esses elementos parecem se organizar num padrão pericelular nas células invasivas das bordas do tumor e nas células C6 migrando pelos vasos. A expressão de moléculas de adesão mostrou que o RHAMM pode ter um papel mais importante que o CD44 no reconhecimento do ácido hialurônico. A expressão de flt-1 e flk-1 pelas células tumorais sugere um papel desses receptores do VEGF não apenas na proliferação endotelial, mas também na proliferação tumoral. Todas as moléculas aqui analisadas são potenciais alvos terapêuticos futuros.Glioblastoma multiforme (GBM) is the most malignant brain tumour and presents high proliferative, invasive and angiogenic capacities. In the present study the spatial distribution of molecules involved with these processes was analyzed in a rat GBM (C6) in vivo. Immunohistochemical analysis showed that tumours expressed extracellular matrix elements (collagens I, III and IV, fibronectin, tenascin C and R, vitronectin and proteoglycans), adhesion molecules (RHAMM, CD44 and integrins) and the proteolytic enzyme MMP-2. At the tumour borders and around the cells migrating along blood vessels these molecules seemed to organize in a pericellular pattern. The adhesion molecules analysis showed that RHAMM could have a pivotal role in hyaluronic acid recognition. Flt-1 and flk-1 expression by tumour cells suggests a role for these VEGF receptors not only in endotheliocyte metabolism, but also in tumour proliferation. All of the studied molecules are potential targets for anti-cancer therapies.
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Krüger, Hagen. "Elektrophysiologische Untersuchungen zu Einflüssen von ionotropen Glutamatantagonisten sowie 5-HT1A-Agonisten auf die Kaliumchlorid-induzierte "spreading depression" im neokortikalen Hirnschnittpräparat der adulten Ratte." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2000. http://dx.doi.org/10.18452/14462.
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Die kortikale spreading depression (SD), wie sie von Leão 1944 zuerst beschrieben wurde, ist ein elektrophysiologisches Phänomen, das in der Pathophysiologie der Aurasymptomatik einer Mi-gräneattacke und Ischämie-induzierter Zellschäden diskutiert wird. Während der akuten fokalen zerebralen Ischämie treten eine Reihe von Ereignissen wie eine massive Entzündungsreaktion und die allmähliche Einbeziehung einer zunächst viablen ischämischen Randzone - der Penum-bra - in das infarzierte Hirngewebe auf. Da an diesen Ereignissen SD-ähnliche Depolarisationen kausal beteiligt sind, ist die pharmakologische Verringerung von SD-Episoden bzw. eine Ver-kleinerung ihrer Amplitude und Dauer unter in vitro als auch tierexperimentellen in vivo Bedin-gungen eine mögliche neuroprotektive Strategie. In der vorliegenden Arbeit wurde ein in vitro Modell beschrieben, das am Hirnschnittpräparat des Neokortex der adulten Ratte eine reproduzierbare Auslösung von SD-Wellen unter normoxi-schen Bedingungen gestattet. Anhand von charakteristischen elektrophysiologischen Parametern einer SD wie Amplitude, Dauer und Ausbreitungsgeschwindigkeit wurden die gute Überein-stimmungen dieses in vitro Modells mit in vivo Modellen gezeigt. Obwohl SD Wellen am nicht-ischämischen Kortex keine morphologischen Schäden verursachen, zeigte sich in den hier vorge-stellten Experimenten eine funktionelle Unterdrückung der GABAergen hemmenden Mechanis-men des Neokortex nach repetitiven SDs auch bei ausreichender Energie- und Sauerstoffversor-gung. Die hier diskutierten Ergebnisse demonstrierten, daß unter in vitro Bedingungen der AMPA-Glutamatrezeptor für die Auslösung und Ausbreitung einer SD eine untergeordnete Rolle spielt. Demgegenüber erwies sich die NMDA-Rezeptoraktivierung als herausragend für eine SD, da die Blockade dieses Rezeptors mit dem nicht-kompetitiven Antagonisten Ketamin die SD-Amplitude und SD-Dauer signifikant verringerte. Die Anwendung der selektiven 5-HT1A-Agonisten 8-OH-DPAT und BAY x 3702 erwies sich als eine neue Möglichkeit, die Zeitdauer einer SD zu verringern. Die aufgezeigte SD-induzierte neuronale Hyperexzitabilität kann unter normoxischen Bedingun-gen zelluläre Dysfunktionen verursachen und auch an einer Generierung der Aura eines Migrä-neanfalls beteiligt sein. Unter hypoxisch-ischämischen Bedingungen könnte eine SD-induzierte Dysfunktion GABAerger Kontrollmechanismen die Ausweitung ischämischer Zellschäden be-wirken. Die Hoffnungen auf eine effektive Schlaganfalltherapie haben sich mit den bisherigen NMDA-Antagonisten trotz ihrer hier bestätigten guten in vitro Wirksamkeit aufgrund der Interferenz mit physiologischen Glutamatfunktionen im Kortex nicht erfüllt. Die hier gezeigte konzentrationsab-hängige Verkürzung der SD-Dauer durch die Aktivierung des 5-HT1A-Serotoninrezeptors unter in vitro Bedingungen kann bei der bekannten hohen 5-HT1A-Rezeptor-mRNA-dichte an beson-ders ischämievulnerablen Neuronen einen neuen neuroprotektiven Ansatz auch beim Menschen darstellen. Weitere Untersuchungen müssen zeigen, ob die hier beschriebene enge Verflechtung des serotonergen Systems mit der glutamatergen Neurotransmission eventuell auch zu uner-wünschte Wirkungen unter in vivo Bedingungen führt.Repetitive cortical spreading depression (SD) and SD-like events, associated with a massive de-polarization of neuronal and glial cells, is thought to play a key role in the induction of neuronal damage in the peri-infarct zone following experimental focal cerebral ischemia. In addition, ex-perimental and clinical data suggest that SD is the underlying mechanism of neurological distur-bances during migraine auras as well. However, detailed analyses on the consequences of repeti-tive SDs on cortical function and involved receptors are lacking. Using an in vitro rat model of SD I investigated in this thesis the electrophysiological properties of repetitive potassium chloride (KCl)-induced SDs, their influence on synaptic neurotransmis-sion and the effects of ionotropic glutamate antagonists and 5-HT1A agonists in neocortical slices obtained from adult rats. Whereas repetitive SDs revealed only non-significant variations in du-ration, amplitude and integral when elicited at intervals of 30 min, paired-pulse inhibition of ex-tracellularly recorded field potential responses was significantly affected by repetitive SD even under normoxic conditions. Compared to the control recordings, each SD episode caused a sig-nificant decrease in the efficacy of intracortical GABAergic inhibition by approximately 10%. Since excitatory synaptic transmission was unaffected, these data indicate that repetitive SDs cause a selective suppression of GABAergic function even in the non-ischemic brain. None of the compounds tested prevented the SD-induced cortical disinhibition. However, the SD-associated negative shift in the extracellular DC potential was reduced by ketamine, a selective N-methyl-D-aspartic acid (NMDA-) receptor antagonist. Ketamine significantly (p < 0.01) re-duced the amplitude of the first SD peak and blocked the second SD peak. Ketamine also de-creased the SD duration at half maximal amplitude (p < 0.05). NBQX, a selective a-amino-3- hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist did not affect the SD-accompanied cortical depolarization, whereas selective 5-hydroxytryptamine (5-HT)1A receptor agonists 8-OH-DPAT and BAY x 3702 shortened concentration-dependently the duration of the SD up to 50 %. Nevertheless, both 5-HT1A receptor agonists caused a strong disinhibition of neu-ronal function with a tendency towards paired-pulse facilitation as well. Thus, repetitive SD and SD-like events may induce neuronal hyperexcitability due to a selective suppression of intrinsic inhibitory GABAergic function. Under normoxic conditions, SD-induced disinhibition may be involved in the generation and maintenance of migraine or associated neurological disturbances. Under hypoxic-ischemic conditions, neuronal hyperexcitability may contribute to the gradual expansion of the ischemic core and the metabolic deterioration of the penumbral tissue after SD episodes. This underlines the deleterious effect of SD to the outcome of focal cerebral ischemia. Although the precise mecha-nisms of SD generation and propagation remains far from established, the present pharmacologi-cal profile of KCl-induced SD in vitro links the induction and propagation of SD in rat neocorti-cal slices mainly to a local increase of [K + ] e and a subsequent activation of NMDA- receptors. This corroborates the neuroprotective effect of a NMDA- receptor blockade observed in various in vitro and in vivo models. However, as it has been demonstrated in clinical trials, NMDA- re-ceptor antagonists in use today cause psychomimetic and cardiovascular side effects in humans and are therefore currently of low clinical benefit. The activation of 5-HT1A receptors by selective agonists represents a new pharmacological strategy in the treatment of acute ischemic stroke, since shortened SD waves may represent a less energy-consuming process under conditions of limited energy supply and are probably associated with an efflux of excitatory neurotransmitters to a lesser extent. The potential clinical benefit of 5-HT 1A receptor agonists remains to be investi-gated in clinical trials, since systemic administration of these compounds after the onset of acute focal cerebral ischemia might interfere with normal functions of glutamatergic neurotransmission in the intact, non-ischemic brain.
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Zbrzeski, Adeline. "Circuits intégrés d’enregistrement et d’analyse en temps réel des potentiels de champ neuronaux : application au traitement de la maladie de Parkinson, par contrôle adaptatif de stimulations cérébrales profondes." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14328/document.
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La maladie de Parkinson est la seconde maladie neuro-dégénérative la plus fréquente à travers le monde. Dans ce contexte, le projet de recherche associé à cette thèse vise à améliorer le traitement symptomatique de la maladie de Parkinson, par le développement de procédés de stimulation cérébrale profonde adaptative. Le travail de cette thèse repose sur la conception d’un ASIC d’enregistrement et de traitement de signaux neuronaux, répondant à divers enjeux :un traitement continu et en temps réel focalisé sur des bandes spécifiques très basses-fréquences et largement configurables. L’objectif est d’utiliser l’information traitée pour le contrôle et la génération d’un signal de stimulation. Cet ASIC a été développé, caractérisé électroniquement et utilisé dans un contexte in vivo. Un système en boucle fermée a été réalisé à partir de cet ASIC, se montrant fonctionnel. Ces validations expérimentales in vivo ouvrent de nombreuses possibilités d’investigation du concept de stimulation cérébrale en boucle ferméeParkinson’s disease is the second most common neurodegenerative diseases throughout theworld. In this context, the research project associated with this thesis is to improve the symptomatictreatment of Parkinson’s disease through the development process of deep brain stimulationadaptive. The work of this thesis is based on the design of an ASIC for recording andprocessing of neural signals, in response to a variety of issues : ongoing treatment and real-timefocus on specific bands of very low-frequency and highly configurable. The goal is to use theprocessed information to the control and generation of a stimulation signal. This ASIC wasdeveloped, characterized and used electronically in a context in vivo. A closed-loop system wasmade from the ASIC, showing functional. These in vivo validations open up many possibilitiesfor investigation of the concept of closed-loop brain stimulation
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Hammad, Mira. "Reconstruction of auricular cartilage using natural-derived scaffolds with an in vivo application in rabbit model Effects of hypoxia on chondrogenic differentiation of progenitor cells from different origins Cell sheets as tools for ear cartilage reconstruction in vivo Cartilage tissue engineering using apple cellulosic scaffolds Cell-secreted matrices as cell supports: Novel approaches for cell culture applications." Thesis, Normandie, 2021. http://www.theses.fr/2021NORMC404.
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La reconstruction des défauts du cartilage auriculaire nécessite une restauration appropriée par des sources cellulaires adéquates ainsi que la fourniture de supports appropriés pour les tissus. Ce travail visait à étudier différents échafaudages et biomatériaux pour l'ingénierie in vitro du cartilage auriculaire ainsi que la réparation in vivo du cartilage auriculaire chez des modèles de lapin. Nous avons d'abord montré que les périchondrocytes auriculaires sont les meilleurs candidats pour la régénération du cartilage auriculaire et que l'hypoxie n'est pas nécessaire à leur différenciation chondrogénique. Ces cellules ont formé avec succès des feuillets de cellules cartilagineuses que nous avons utilisés pour régénérer le tissu cartilagineux in vitro et pour combler et reconstruire les défauts du cartilage in vivo dans des modèles allogèniques de lapins. Nous avons ensuite testé des tissus dérivés de la cellulose en décellularisant un tissu de pomme. Une fois recolonisés avec des cellules, ces échafaudages ont surpassé les hydrogels d'alginate en augmentant la croissance et en régulant l'expression cartilagineuse dans différentes cellules de mammifères. Dans la dernière partie de la thèse, nous avons examiné des matrices sécrétées par les cellules et les avons utilisées comme revêtement pour différentes applications de culture cellulaire. Il est intéressant de noter que ces supports, une fois lyophilisés, ont favorisé la culture de cellules allo- et xénogéniques, augmenté la prolifération et stimulé la chondrogenèse. Nous avons également mis en évidence la préservation du phénotype lors de l’amplification des chondrocytes par passages successifs. Notre étude fournit de nouveaux outils et approches pour de multiples applications de culture cellulaireSuccessful reconstruction of auricular cartilage defects requires the appropriate restoration of the cartilaginous deformities by potential cell sources as well as providing suitable tissue supports. This work aimed to investigate different scaffolds and biomaterials for in vitro auricular cartilage engineering as well as in vivo auricular cartilage repair in rabbit models. We first showed that auricular perichondrocytes are the best candidates for auricular cartilage regeneration and hypoxia is not necessary for their chondrogenic differentiation. These cells successfully formed cartilaginous cell sheets which were used to regenerate cartilage tissue in vitro and to fill and reconstruct cartilage defects in vivo in allogenic rabbit models. Furthermore, we tested cellulose-derived tissue by decellularizing apple tissue and its use as a scaffold. Repopulated with cells, these scaffolds surpassed alginate hydrogels by enhancing colonization and upregulating the cartilaginous expression in different mammalian cells. In the final part of the thesis, we examined cell-secreted matrices and used them as a coating for different cell culture applications. Interestingly, these coatings promoted both allo- and xenogeneic cell culture, increased proliferation, and boosted chondrogenesis. We also highlighted phenotype preservation during chondrocytes expansion on these cell-secreted matrices. Our study provides novel tools and approaches for multiple cell culture applications
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Driffort, Virginie. "Rôle du canal sodique NaV1.5 et de la sous-unité auxiliaire β4 dans l’invasivité des cellules cancéreuses mammaires in vitro et in vivo." Thesis, Tours, 2014. http://www.theses.fr/2014TOUR3310.
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L’expression anormale du canal sodique Nav1.5 dans le cancer du sein est corrélée au développement métastatique et à une mortalité augmentée. Le canal Nav1.5 est localisé dans les invadopodes des cellules cancéreuses mammaires humaines MDA-MB-231 et augmente leur activité protéolytique par une modulation allostérique de l’échangeur NHE-1 et l’activation de protéases acides. In vivo, dans un modèle de xénogreffe sur souris NMRI nude, l’expression de Nav1.5 potentialise la colonisation des poumons par les cellules cancéreuses mammaires humaines. Cette colonisation métastatique est inhibée par un traitement à la ranolazine, un inhibiteur pharmacologique des canaux Nav1.5. La sous-unité β4, auxiliaire des canaux Nav, voit son expression diminuer au cours de la progression cancéreuse, ce qui est associé in vitro à une augmentation de l’invasivité cellulaire. Cette augmentation d’invasivité semble indépendante du canal Nav1.5 et pourrait être associée à une transition des cellules vers un phénotype amiboïde. En conclusion, l’expression de Nav1.5 et la perte d’expression de β4 semblent jouer des rôles complémentaires dans l’invasivité des cellules cancéreusesThe abnormal expression of sodium channel Nav1.5 in breast cancer is correlated with metastatic development and an increased mortality. The Nav1.5 channel is located in invadopodia in human breast cancer cells MDA-MB-231, where it increases proteolytic activity by allosteric modulation of exchanger NHE-1 and activation of acidic proteases. In vivo, in a xenograft model in nude NMRI mice, the expression of Nav1.5 potentiates lung colonization by human breast cancer cells. Metastatic colonization is inhibited by treatment with ranolazine, a pharmacological inhibitor of Nav1.5. The β4 subunit, an auxiliary subunit of Nav channels, is expressed at low levels or lost when tumors are more aggressive, and its suppression in vitro increases celI invasiveness. This increase seems to be independent of Nav1.5 and could be associated with the transition of cells to an amoeboid phenotype. In conclusion, Nav1.5 expression and the loss of β4 expression seem to play complementary roles in the invasiveness of cancer cells
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Zanona, Querusche Klippel. "Estudo dos efeitos da MT3 na plasticidade sináptica de longa duração e interações com a sinalização gabaérgica em hipocampo dorsal pela eletrofisiologia in vivo em animal anestesiado." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/132342.
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A sinalização muscarínica exerce função modulatória sobre diferentes aspectos da cognição e emoções. Todos os cinco subtipos de receptores muscarínicos (mAChR), M1 a M5, são expressos no hipocampo de mamíferos e são ativados de forma sobreposta pela maioria dos fármacos, dificultando avanços significativos na compreensão da contribuição de cada componente desse sistema. A toxina muscarínica 3 (MT3) é um antagonista seletivo para o subtipo M4, permitindo a investigação das ações modulatórias deste receptor no aprendizado, memória e plasticidade sináptica. Os M4 são receptores acoplados à proteína G (GPCRs) que atuam via Gi/o desencadeando efeitos inibitórios sobre as células em que estão presentes. Estudos comportamentais anteriores indicam que a administração de MT3 imediatamente após o treino em uma tarefa aversiva produz efeito amnéstico, enquanto que a administração antes da evocação, causa facilitação. Uma explicação para estes resultados é que os circuitos locais envolvidos na consolidação e na evocação da memória diferem em sua natureza. Nesse contexto, sugere-se que o efeito amnéstico da MT3 sobre a consolidação seja consequência da supressão da inibição de interneurônios GABAérgicos; enquanto que na evocação, esse efeito se daria sobre as sinapses glutamatérgicas. Assim, no presente trabalho, com o objetivo de investigar como o receptor M4 modula a plasticidade sináptica de longa duração e interage com uma dessas sinalizações, no caso a GABAérgica, utilizou-se a técnica de eletrofisiologia in vivo de hipocampo de ratos anestesiados. Para tanto, foram realizados registros extracelulares do potencial excitatório pós-sináptico de campo (fEPSP) de CA1 evocados por estimulação contralateral da via Colateral de Schaffer com infusão dos fármacos 15 min antes ou depois da estimulação elétrica de alta ou baixa frequência (HFS: 10 trens 0,5 Hz, 20 pulsos 100 Hz; ou LFS: 600 pulsos 1 Hz, respectivamente). MT3 (4,0 μg/μl), bicuculina (0,06 μg/μl), baclofen (0,2 μg/μl) e veículo, isoladamente ou combinados, não alteraram a amplitude da resposta evocada basal ou a facilitação por pulso pareado (FPP) 15 min após a infusão. MT3 aparentemente atenuou, mas não de forma significativa, a potenciação de longa duração (LTP) em relação ao controle (potenciação 60 min após a HFS de 31,8% e 66,0%, respectivamente). Além disso, não houve diferença significativa entre a amplitude do fEPSP no período basal e 60 min após a HFS sob ação da MT3. Bicuculina, embora não tenha abolido a LTP e nem causado alteração na FPP, produziu uma potenciação de apenas 36,4%. Baclofen promoveu uma potenciação semelhante à dos controles. A administração de baclofen também reduziu significativamente a FPP em relação ao basal. A administração conjunta de MT3 com bicuculina ou baclofen promoveu uma potenciação semelhante ao controle. MT3 não apresentou efeito sobre a manutenção da LTP quando aplicada 15 min após a HFS. Por fim, não foi possível induzir a depressão de longa duração (LTD) com o protocolo de LFS utilizado. Embora não tenha ocorrido diferença estatisticamente significativa entre os grupos devido ao baixo número de animais utilizados, os dados sugerem a possibilidade de uma amplitude reduzida da LTP quando da injeção de bicuculina. Baclofen alterou a FPP em relação ao fEPSP basal, o mesmo não tendo sido observado no grupo controle. Com a administração concomitante de MT3, tais alterações deixam de ser identificadas. Ainda que os achados experimentais sejam inconclusivos e preliminares, este trabalho permitiu a padronização da técnica de eletrofisiologia in vivo em animal anestesiado o que abre portas para futuras investigações.The cholinergic muscarinic system exerts modulatory function over different aspects of cognition and emotion. All five muscarinic receptors subtypes (mAChR), M1 to M5, are expressed at mammals hippocampus and at least two of them are simultaneously activated by most of the drugs, hindering significant advances on the role of each component of this system. The muscarinic toxin 3 (MT3) is a selective antagonist for the M4 subtype, allowing the investigation of the modulatory actions of this receptor over learning, memory and synaptic plasticity. The M4 are G protein coupled receptors (GPCRs) that act through Gi/o triggering inhibitory effects on which cells they are occur. Previous behavioral studies have shown that administration of MT3 soon after aversive task training exerts amnestic effects over memory, while administration prior to recall, leads to facilitation. A possible explanation to these results could be that the local circuits involved on memory consolidation and recall are different in nature. On this perspective, the amnestic effect of MT3 over memory consolidation should be consequence of GABAergic interneurons inhibition suppression; while the effect on recall, should be over glutamatergic synapses modulation. Thereby, the present work, with the objective to investigate how the M4 receptor modulates long-term synaptic plasticity and interacts with the GABAergic system, in vivo electrophysiological approach of anesthetized rats’ hippocampus was applied. Hence, field excitatory postsynaptic potentials (fEPSP) from CA1 were recorded after stimulation of contralateral Schaffer Collateral pathway with drugs infusion 15 min before or after high or low frequency electric stimulation (HFS: 10 trains 0.5 Hz, 20 pulses 100 Hz; LFS: 600 pulses 1 Hz, respectively). Neither MT3 (4.00 μg/μl), bicuculline (0.06 μg/μl), baclofen (0.20 μg/μl) nor vehicle, isolated or combined, changed the baseline evoked response amplitude 15 min after infusion nor the paired-pulse facilitation ratio (PPF). MT3 apparently attenuated, but not significantly, the long-term potentiation (LTP) compared to control (31.8% and 66.0% potentiation 60 min after HFS, respectively). In addition, there was no significant difference between baseline and 60 min after HFS fEPSP amplitude at MT3 group. Bicuculline, although did not abolish LTP neither changed PPF, it did produce a potentiation of only 36.4%. Baclofen induced a potentiation similar to control group. Baclofen administration also significantly reduced PPF compared to baseline. The simultaneous administration of MT3 and bicuculline or baclofen led to a potentiation similar to the control group. MT3 did not show any effect over LTP maintenance when applied 15 min after HFS. Lastly, it was not possible to induce long-term depression (LTD) with the used LFS protocol. Although there was no statistical significance between groups due to the low animal numbers used, data suggest that bicuculline had reduced LTP amplitude. Baclofen did alter PPF and the same was not observed on control group. When bicuculline or baclofen were injected with MT3, those alterations were not observed. These are inconclusive and preliminary results, notwithstanding this work allowed to set up the in vivo electrophysiology technique in anesthetized animals what will provide new tools for future research.
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Steidl, Esther. "Mise au point d’une plateforme de tests in vitro pour l’évaluation du potentiel proconvulsivant de façon précoce au cours du développement de médicaments." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0050.
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L’objectif des travaux de recherche présentés ici était la mise au point d’une plateforme de tests pour identifier le potentiel proconvulsivant de composés de façon précoce au cours de leur développement. Ces tests ont été réalisés in vitro à partir de tranches d’hippocampes enregistrées à l’aide de multi-electrode arrays (MEA). La technique du MEA est particulièrement adaptée pour ce type d’investigations car elle permet d’évaluer l’effet de composés sur une large partie d’un réseau neuronal natif. De plus, cette technique permet de réaliser des tests à moyen débit et à partir de faibles quantités de composé.Tout d’abord, l’évaluation de composés de référence a permis de déterminer les paramètres d’intérêt, qui sont modifiés par des composés proconvulsivants. Les composés proconvulsivants testés ont causé une augmentation de l’aire des potentiels d’action de population et l’apparition de potentiels d’action additionnels, déclenché des décharges épileptiformes et/ou augmenté la fréquence de décharge des neurones de la région CA1. Les conditions expérimentales des tests réalisés ont ensuite été modifiées pour augmenter leur sensibilité et permettre la détection de proconvulsivants faibles. Cette plateforme de 3 tests complémentaires a été nommée NS-PC set. Pour valider la plateforme NS-PC set, 15 composés fournis par des sociétés pharmaceutiques partenaires, incluant des contrôles positifs et négatifs, ont été testés à l’aveugle. Un nouveau type de test plus rapide et abordable appelé NS-PC screen a ensuite été mis au point, sur la base d’enregistrement de décharges épileptiformes induites par la 4-aminopyridine dans des tranches d’hippocampeThe goal of the present work was to develop a platform of tests that could predict the proconvulsive potential of compounds in development as early as possible during preclinical phases. These tests were carried out in vitro from hippocampal slices recorded with multi-electrode arrays (MEAs). The MEA technology is particularly adapted because it allows to investigate compounds’ effect on a wide area of a native neural network, including all the complexity and organization of the different cell types. In addition, rapidity and low compound consumption of the MEA-based assays make them suitable for early stages of development.First, the evaluation of reference proconvulsive/seizurogenic compounds allowed to determine the parameters that should be monitored to detect proconvulsive properties. It appeared that reference compounds triggered one or several of the following effects: increase of the population spikes area and repetition of spikes, triggering of epileptiform discharges and/or increase of the CA1 neurons firing. The experimental conditions of the assays were then modified to increase their sensitivity and thus detect even weak proconvulsive compounds. This platform of 3 complementary assays was termed NS-PC set.15 compounds, including positive and negative controls, were provided by partner pharmaceutical companies to be tested under blind conditions on NS-PC set. A new faster and cheaper assay, termed NS-PC screen, was also designed based on the recording of 4-aminopyridine-induced epileptiform discharges in hippocampal slices
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Pye, Richard Laurence. "Measuring the Acute Physiological Effects of Leptin in the Carotid Body." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1449583350.
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Erlandson, Melissa. "Investigating the plasticity of sensory cortical circuits in the context of learning in the wild-type mouse and a conditional mouse model of fragile X syndrome." Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0342.
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L'objectif de ce projet est l’étude de la plasticité des circuits corticaux dans le contexte de l'apprentissage des souris « sauvages » et modèles du syndrome de l’X fragile. Des études sur l'efficacité de la combinaison d'enregistrement des potentiels de champ locaux extracellulaires avec la stimulation laser UV (LSPS) pour cartographier les réseaux ont été réalisées. Nous avons trouvé des enregistrements de champs extracellulaires qui pourraient être utilisés pour détecter les réponses synaptiques évoquées par LSPS. Nos résultats indiquent une méthode alternative pour obtenir des cartes complètes de réseaux intracorticaux excitateurs. Ensuite, nous avons développé un paradigme d'apprentissage associatif sensoriel et étudié ses effets sur les réseaux intracorticaux excitateurs du cortex baril. Ex vivo un affaiblissement des projections excitatrices entre les couches 4 et 2/3 qui dans les colonnes de vibrisses C a été observée. Enfin, nous avons utilisé ces mêmes approches dans une souris modèle du syndrome de l'X fragile (FXS). Pour étudier les liens entre les déficits sensoriels, l'apprentissage associatif et les altérations fonctionnelles des réseaux sensoriels, nous avons utilisé un modèle de souris mutantes dans lequel la pathologie FXS était ciblée sur la couche 4 du cortex somatosensoriel. Il a été constaté que les souris WT présentaient une dépression similaire, alors qu'elle était absente FXS. En conclusion, les études sur les mutants sensoriels de type sauvage ont mis en lumière les conséquences de l'apprentissage sur les réseaux corticaux sensoriels et les liens entre la plasticité des réseaux corticaux sensoriels et les capacités cognitivesThe aim of this project is to study the plasticity of the cortical circuits in the context of the learning of wild type mice and models of Fragile X Syndrome. First, investigations into the efficacy of recording combination of extracellular local field potentials with UV laser stimulation (LSPS) to map networks were performed. We found extracellular field records could be used to detect the synaptic responses evoked by LSPS. Our results indicate an alternative method for obtaining complete maps of excitatory intracortical networks. Next, we developed a sensory associative learning paradigm and studied its effects on excitatory intracortical networks the barrel cortex. Ex vivo a weakening of the excitatory projections between layers 4 and 2/3 which in the columns of vibrissae C was observed and declined function of the speed of the behavioural response. Finally, we used these same approaches in a Fragile X Syndrome (FXS) model mouse. To study the links between sensory deficits, associative learning, and functional alterations of sensory networks, we used a model of mutant mice in which the FXS pathology was targeted to the layer 4 of the somatosensory cortex. Our hypotheses were that behavioural conditioning would change the cortical sensory circuits of the FXS sensory mutant and that the abnormal plasticity of these circuits would in turn affect the performance. It was found the WT mice exhibited a similar depression, whereas it was absent FXS. In conclusion, wild type mouse and FXS sensory mutant studies shed light on the consequences of learning on sensory cortical networks and on the links between plasticity of sensory cortical networks and cognitive abilities
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Urbanova, Veronika. "Electrodes poreuses pour applications (bio)analytiques." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14026/document.
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Dans cette mémoire nous discutons l´élaboration d´électrodes poreuses par un processus de type “template” et leur application potentielle dans le domaine de l´analyse environnementale et neurobiologique. La première partie de ce travail est dédiée à l'élaboration d’électrodes poreuses de bismuth et d'antimoine. Ces électrodes montrent des limites de détection améliorées par rapport à des électrodes non poreuses, ouvrant ainsi des applications prometteuses dans le domaine de l'analyse de trace. La deuxième partie vise à surmonter des facteurs limitants de micro-électrodes dans le cadre de l'enregistrement de signaux extracellulaires et la stimulation de réseaux neuronaux en culture, qui peut donner des informations sur des interactions et des phénomènes synergétiques dans les systèmes nerveuxIn the present dissertation thesis the elaboration of porous electrodes via templating methods and their potential application in the field of environmental and neurobiological analysis are discussed. The electrodes of controlled porosity are characterized by an increased internal electroactive area and thus they can be used to enhance significantly the electrochemical performance. High surface area materials are promising for biosensing and more generally in electrochemical experiments. The first part of this work is focused on the elaboration of porous bismuth and antimony film electrodes. These porous electrodes show improved detection limits compared to non-porous one and thus open up promising applications in the field of trace analysis. The second part deals with overcoming limiting factors of microelectrode arrays in the context of extracellular recording and stimulating cellular neuronal networks or neural tissues in culture that can reveal information about interactions and synergetic features of nervous systems