93 results on '"Pralong, E."'
Search Results
52. POTENCY OF DAP5 AND CGP 40 116 ON THE NMDAMEDIATED POSTSYNAPTIC RESPONSES OF BASOLATERAL AMYGDALA NEURONES IN VITRO
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FERRY, B, MAGISTRETTI, P J, and PRALONG, E
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- 1996
53. P19.8 Assessment of the vegetative comatose state with cognitive evoked potentials (CEPs) and fMRI: Implications for the consciousness model of Damasio and Guerit
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Debatisse, D., Fornari, E., Pralong, E., Maeder, P., Foroglou, H., Tetreault, M.H., and Villemure, J.G.
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- 2006
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54. Central quadrantotomy for intractable childhood epilepsy: operative technique and functional neuroanatomy.
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Cossu G, Aureli V, Roulet-Perez E, Thomas C, Marston JS, Pralong E, Messerer M, González-López P, and Daniel RT
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- Female, Humans, Child, Neuroanatomy, Cerebral Cortex diagnostic imaging, Cerebral Cortex surgery, Seizures, Treatment Outcome, Magnetic Resonance Imaging, Electroencephalography, Drug Resistant Epilepsy diagnostic imaging, Drug Resistant Epilepsy surgery, Epilepsy diagnostic imaging, Epilepsy surgery, Epilepsy pathology
- Abstract
Refractory subhemispheric epilepsy has been traditionally treated by resection. The last few decades have seen the emergence of disconnective techniques, for both hemispheric and subhemispheric disease. The aim of this study was to describe the technique for a disconnective surgery for large epileptogenic lesions involving the central (perirolandic cortices), parietal, and occipital lobes. This junctional cortex within the hemisphere (in contrast to anterior and posterior quadrantotomies) presents unique challenges when contemplating a complete disconnection of the region. The surgical technique is achieved through six distinct steps: fronto-central, inferior frontoparietal, lateral temporo-occipital, medial frontal, basal temporo-occipital, and posterior parasagittal callosal disconnections. The functional neuroanatomy of each step is described, along with cadaveric dissections. The authors describe this technique and include a case description of a young girl who presented with childhood-onset intractable epilepsy associated with cognitive stagnation. The postoperative seizure outcome in this patient remains excellent at 2 years' follow-up, with gains in cognition and behavior. Excellent seizure outcomes can be achieved if the network encompassing the entire epileptogenic cortex is disconnected while ensuring preservation of fiber systems that link functionally eloquent uninvolved cortices adjacent to the central quadrant.
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- 2023
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55. Activation of lactate receptor HCAR1 down-modulates neuronal activity in rodent and human brain tissue.
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Briquet M, Rocher AB, Alessandri M, Rosenberg N, de Castro Abrantes H, Wellbourne-Wood J, Schmuziger C, Ginet V, Puyal J, Pralong E, Daniel RT, Offermanns S, and Chatton JY
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- Animals, Brain, Excitatory Postsynaptic Potentials physiology, Humans, Lactic Acid, Mice, Rats, Dentate Gyrus physiology, Epilepsy, Neurons physiology, Receptors, G-Protein-Coupled metabolism
- Abstract
Lactate can be used by neurons as an energy substrate to support their activity. Evidence suggests that lactate also acts on a metabotropic receptor called HCAR1, first described in the adipose tissue. Whether HCAR1 also modulates neuronal circuits remains unclear. In this study, using qRT-PCR, we show that HCAR1 is present in the human brain of epileptic patients who underwent resective surgery. In brain slices from these patients, pharmacological HCAR1 activation using a non-metabolized agonist decreased the frequency of both spontaneous neuronal Ca
2+ spiking and excitatory post-synaptic currents (sEPSCs). In mouse brains, we found HCAR1 expression in different regions using a fluorescent reporter mouse line and in situ hybridization. In the dentate gyrus, HCAR1 is mainly present in mossy cells, key players in the hippocampal excitatory circuitry and known to be involved in temporal lobe epilepsy. By using whole-cell patch clamp recordings in mouse and rat slices, we found that HCAR1 activation causes a decrease in excitability, sEPSCs, and miniature EPSCs frequency of granule cells, the main output of mossy cells. Overall, we propose that lactate can be considered a neuromodulator decreasing synaptic activity in human and rodent brains, which makes HCAR1 an attractive target for the treatment of epilepsy.- Published
- 2022
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56. Direct cochlear nerve stimulation monitoring through evoked muscle responses during retrosigmoid vestibular schwannoma resection surgery: technical note.
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Starnoni D, Cossu G, Maduri R, Tuleasca C, George M, Maire R, Messerer M, Levivier M, Pralong E, and Daniel RT
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- Humans, Cochlear Nerve physiology, Hearing physiology, Cochlea, Muscles, Evoked Potentials, Auditory, Brain Stem physiology, Neuroma, Acoustic surgery
- Abstract
Objective: Cochlear nerve preservation during surgery for vestibular schwannoma (VS) may be challenging. Brainstem auditory evoked potentials and cochlear compound nerve action potentials have clearly shown their limitations in surgeries for large VSs. In this paper, the authors report their preliminary results after direct electrical intraoperative cochlear nerve stimulation and recording of the postauricular muscle response (PAMR) during resection of large VSs., Methods: The details for the electrode setup, stimulation, and recording parameters are provided. Data of patients for whom PAMR was recorded during surgery were prospectively collected and analyzed., Results: PAMRs were recorded in all patients at the ipsilateral vertex-earlobe scalp electrode, and in 90% of the patients they were also observed in the contralateral electrode. The optimal stimulation intensity was found to be 1 mA at 1 Hz, with a good cochlear response and an absent response from other nerves. At that intensity, the ipsilateral cochlear response had an initial peak at a mean (± SEM) latency of 11.6 ± 1.5 msec with an average amplitude of 14.4 ± 5.4 µV. One patient experienced a significant improvement in his audition, while that of the other patients remained stable., Conclusions: PAMR monitoring may be useful in mapping the position and trajectory of the cochlear nerve to enable hearing preservation during surgery.
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- 2022
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57. Activity-dependent spinal cord neuromodulation rapidly restores trunk and leg motor functions after complete paralysis.
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Rowald A, Komi S, Demesmaeker R, Baaklini E, Hernandez-Charpak SD, Paoles E, Montanaro H, Cassara A, Becce F, Lloyd B, Newton T, Ravier J, Kinany N, D'Ercole M, Paley A, Hankov N, Varescon C, McCracken L, Vat M, Caban M, Watrin A, Jacquet C, Bole-Feysot L, Harte C, Lorach H, Galvez A, Tschopp M, Herrmann N, Wacker M, Geernaert L, Fodor I, Radevich V, Van Den Keybus K, Eberle G, Pralong E, Roulet M, Ledoux JB, Fornari E, Mandija S, Mattera L, Martuzzi R, Nazarian B, Benkler S, Callegari S, Greiner N, Fuhrer B, Froeling M, Buse N, Denison T, Buschman R, Wende C, Ganty D, Bakker J, Delattre V, Lambert H, Minassian K, van den Berg CAT, Kavounoudias A, Micera S, Van De Ville D, Barraud Q, Kurt E, Kuster N, Neufeld E, Capogrosso M, Asboth L, Wagner FB, Bloch J, and Courtine G
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- Humans, Leg, Paralysis rehabilitation, Spinal Cord physiology, Walking physiology, Spinal Cord Injuries rehabilitation, Spinal Cord Stimulation
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Epidural electrical stimulation (EES) targeting the dorsal roots of lumbosacral segments restores walking in people with spinal cord injury (SCI). However, EES is delivered with multielectrode paddle leads that were originally designed to target the dorsal column of the spinal cord. Here, we hypothesized that an arrangement of electrodes targeting the ensemble of dorsal roots involved in leg and trunk movements would result in superior efficacy, restoring more diverse motor activities after the most severe SCI. To test this hypothesis, we established a computational framework that informed the optimal arrangement of electrodes on a new paddle lead and guided its neurosurgical positioning. We also developed software supporting the rapid configuration of activity-specific stimulation programs that reproduced the natural activation of motor neurons underlying each activity. We tested these neurotechnologies in three individuals with complete sensorimotor paralysis as part of an ongoing clinical trial ( www.clinicaltrials.gov identifier NCT02936453). Within a single day, activity-specific stimulation programs enabled these three individuals to stand, walk, cycle, swim and control trunk movements. Neurorehabilitation mediated sufficient improvement to restore these activities in community settings, opening a realistic path to support everyday mobility with EES in people with SCI., (© 2022. The Author(s), under exclusive licence to Springer Nature America, Inc.)
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- 2022
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58. Anterior peri-insular quadrantotomy: a cadaveric white matter dissection study.
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Gonzalez-Lopez P, Cossu G, Pralong E, Baldoncini M, Messerer M, and Daniel RT
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Objective: Anterior quadrant disconnection represents a safe surgical option in well-selected pediatric patients with a large frontal lobe lesion anterior to the motor cortex. The understanding of the anatomy of the white matter tracts connecting the frontal lobe with the rest of the cerebrum forms the basis of a safe and successful disconnective surgery. The authors explored and illustrated the relevant white matter tracts sectioned during each surgical step using fiber dissection techniques., Methods: Five human cadaveric hemispheres were dissected to illustrate the frontal connections in the 3 planes. The dissections were performed from lateral to medial, medial to lateral, and ventral to dorsal to describe the various tracts sectioned during the 4 steps of this surgery, namely the anterior suprainsular window, intrafrontal disconnection, anterior callosotomy, and frontobasal disconnection., Results: At the beginning of each surgical step, the U fibers were cut. During the anterior suprainsular window, the superior longitudinal fasciculus (SLF), the uncinate fasciculus, and the inferior fronto-occipital fasciculus (IFOF) were visualized and sectioned, followed by sectioning of the anterior limb of the internal capsule. During the intrafrontal disconnection, the SLF was cut, along with the corona radiata. At the medial surface the cingulum was sectioned. The anterior callosotomy disconnected the anterior third of the body of the callosum, the genu, and the rostrum. The frontobasal disconnection addressed the last remaining fibers connecting the frontal lobe with the rest of the hemisphere, namely the anterior limb of the anterior commissure., Conclusions: The anterior peri-insular quadrantotomy aims at effectively treating children with large lesions of the frontal lobe anterior to the motor cortex. A precise understanding of the gyral anatomy of this lobe along with the several white matter connections is crucial to avoid motor complications and to ensure complete disconnection.
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- 2019
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59. Differential contributions of subthalamic beta rhythms and 1/f broadband activity to motor symptoms in Parkinson's disease.
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Martin S, Iturrate I, Chavarriaga R, Leeb R, Sobolewski A, Li AM, Zaldivar J, Peciu-Florianu I, Pralong E, Castro-Jiménez M, Benninger D, Vingerhoets F, Knight RT, Bloch J, and Millán JDR
- Abstract
Excessive beta oscillatory activity in the subthalamic nucleus (STN) is linked to Parkinson's Disease (PD) motor symptoms. However, previous works have been inconsistent regarding the functional role of beta activity in untreated Parkinsonian states, questioning such role. We hypothesized that this inconsistency is due to the influence of electrophysiological broadband activity -a neurophysiological indicator of synaptic excitation/inhibition ratio- that could confound measurements of beta activity in STN recordings. Here we propose a data-driven, automatic and individualized mathematical model that disentangles beta activity and 1/f broadband activity in the STN power spectrum, and investigate the link between these individual components and motor symptoms in thirteen Parkinsonian patients. We show, using both modeled and actual data, how beta oscillatory activity significantly correlates with motor symptoms (bradykinesia and rigidity) only when broadband activity is not considered in the biomarker estimations, providing solid evidence that oscillatory beta activity does correlate with motor symptoms in untreated PD states as well as the significant impact of broadband activity. These findings emphasize the importance of data-driven models and the identification of better biomarkers for characterizing symptom severity and closed-loop applications., Competing Interests: The authors declare no competing interests.
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- 2018
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60. Targeted neurotechnology restores walking in humans with spinal cord injury.
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Wagner FB, Mignardot JB, Le Goff-Mignardot CG, Demesmaeker R, Komi S, Capogrosso M, Rowald A, Seáñez I, Caban M, Pirondini E, Vat M, McCracken LA, Heimgartner R, Fodor I, Watrin A, Seguin P, Paoles E, Van Den Keybus K, Eberle G, Schurch B, Pralong E, Becce F, Prior J, Buse N, Buschman R, Neufeld E, Kuster N, Carda S, von Zitzewitz J, Delattre V, Denison T, Lambert H, Minassian K, Bloch J, and Courtine G
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- Activities of Daily Living, Computer Simulation, Electromyography, Epidural Space, Humans, Leg innervation, Leg physiology, Leg physiopathology, Locomotion physiology, Male, Motor Neurons physiology, Muscle, Skeletal innervation, Muscle, Skeletal physiology, Muscle, Skeletal physiopathology, Paralysis physiopathology, Paralysis surgery, Spinal Cord cytology, Spinal Cord physiology, Spinal Cord physiopathology, Spinal Cord Injuries physiopathology, Spinal Cord Injuries surgery, Biomedical Technology, Electric Stimulation Therapy, Paralysis rehabilitation, Spinal Cord Injuries rehabilitation, Walking physiology
- Abstract
Spinal cord injury leads to severe locomotor deficits or even complete leg paralysis. Here we introduce targeted spinal cord stimulation neurotechnologies that enabled voluntary control of walking in individuals who had sustained a spinal cord injury more than four years ago and presented with permanent motor deficits or complete paralysis despite extensive rehabilitation. Using an implanted pulse generator with real-time triggering capabilities, we delivered trains of spatially selective stimulation to the lumbosacral spinal cord with timing that coincided with the intended movement. Within one week, this spatiotemporal stimulation had re-established adaptive control of paralysed muscles during overground walking. Locomotor performance improved during rehabilitation. After a few months, participants regained voluntary control over previously paralysed muscles without stimulation and could walk or cycle in ecological settings during spatiotemporal stimulation. These results establish a technological framework for improving neurological recovery and supporting the activities of daily living after spinal cord injury.
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- 2018
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61. The Changing Paradigm for the Surgical Treatment of Large Vestibular Schwannomas.
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Daniel RT, Tuleasca C, Rocca A, George M, Pralong E, Schiappacasse L, Zeverino M, Maire R, Messerer M, and Levivier M
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Objective Planned subtotal resection followed by Gamma Knife surgery (GKS) in patients with large vestibular schwannoma (VS) has emerged during the past decade, with the aim of a better functional outcome for facial and cochlear function. Methods We prospectively collected patient data, surgical, and dosimetric parameters of a consecutive series of patients treated by this method at Lausanne University Hospital during the past 8 years. Results A consecutive series of 47 patients were treated between July 2010 and January 2018. The mean follow-up after surgery was 37.5 months (median: 36, range: 0.5-96). Mean presurgical tumor volume was 11.8 mL (1.47-34.9). Postoperative status showed normal facial nerve function (House-Brackmann I) in all patients. In a subgroup of 28 patients, with serviceable hearing before surgery and in which cochlear nerve preservation was attempted at surgery, 26 (92.8%) retained serviceable hearing. Nineteen had good or excellent hearing (Gardner-Robertson class 1) before surgery, and 16 (84.2%) retained it after surgery. Mean duration between surgery and GKS was 6 months (median: 5, range: 3-13.9). Mean residual volume as compared with the preoperative one at GKS was 31%. Mean marginal dose was 12 Gy (11-12). Mean follow-up after GKS was 34.4 months (6-84). Conclusion Our data show excellent results in large VS management with a combined approach of microsurgical subtotal resection and GKS on the residual tumor, with regard to the functional outcome and tumor control. Longer term follow-up is necessary to fully evaluate this approach, especially regarding tumor control.
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- 2018
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62. Cannabinoid-induced alteration of motor-evoked potentials (MEPs) prior to intradural spinal tumor removal: a nasty surprise.
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Pralong E, Maduri R, Daniel RT, and Messerer M
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- Child, Drug Combinations, Female, Humans, Intraoperative Neurophysiological Monitoring, Neurofibromatosis 1 complications, Spinal Cord Neoplasms etiology, Analgesics adverse effects, Cannabidiol adverse effects, Dronabinol adverse effects, Evoked Potentials, Motor drug effects, Spinal Cord Neoplasms surgery
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- 2018
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63. Do intra-operative neurophysiological changes predict functional outcome following decompressive surgery for lumbar spinal stenosis? A prospective study.
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Piasecki K, Kulik G, Pierzchala K, Pralong E, Rao PJ, and Schizas C
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Background: To analyse the relation between immediate intraoperative neurophysiological changes during decompression and clinical outcome in a series of patients with lumbar spinal stenosis (LSS) undergoing surgery., Methods: Twenty-four patients with neurogenic intermittent claudication (NIC) due to LSS undergoing decompressive surgery were prospectively studied. Intra operative trans-cranial motor evoked potentials (tcMEPs) were recorded before and immediately after surgical decompression. Lower limb normalised tcMEP improvement was used as primary neurophysiological outcome. Clinical outcome was assessed using the Zurich Claudication Questionnaire (ZCQ) self-assessment score, before surgery (baseline) and at an average of 8 and 29 months post-operatively., Results: We found a moderate positive correlation between tcMEP changes and ZCQ at early follow-up (R=0.36). At late follow-up no correlation was found between intra-operative tcMEP and ZCQ changes. Dichotomizing the data showed a statistically significant relationship between tcMEP improvement and better functional outcome at early follow-up (P=0.013) but not at later follow-up (P=1)., Conclusions: Our findings suggest that intra-operative neurophysiological improvement during decompressive surgery may predict a better clinical outcome at early follow-up although this is not applicable to late follow-up possibly due to the observed erosion of functional improvement with time., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.
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- 2018
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64. Periinsular anterior quadrantotomy: technical note.
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Cossu G, Lebon S, Seeck M, Pralong E, Messerer M, Roulet-Perez E, and Daniel RT
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- Child, Electroencephalography, Humans, Magnetic Resonance Imaging, Male, Prefrontal Cortex surgery, Epilepsy surgery, Frontal Lobe surgery, Neurosurgical Procedures methods
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Refractory frontal lobe epilepsy has been traditionally treated through a frontal lobectomy. A disconnective technique may allow similar seizure outcomes while avoiding the complications associated with large brain resections. The aim of this study was to describe a new technique of selective disconnection of the frontal lobe that can be performed in cases of refractory epilepsy due to epileptogenic foci involving 1 frontal lobe (anterior to the motor cortex), with preservation of motor function. In addition to the description of the technique, an illustrative case is also presented. This disconnective procedure is divided into 4 steps: the suprainsular window, the anterior callosotomy, the intrafrontal disconnection, and the frontobasal disconnection. The functional neuroanatomy is analyzed in detail for each step of the surgery. It is important to perform cortical and subcortical electrophysiological mapping to guide this disconnective procedure and identify eloquent cortices and intact neural pathways. The authors describe the case of a 9-year-old boy who presented with refractory epilepsy due to epileptogenic foci localized to the right frontal lobe. MRI confirmed the presence of a focal cortical dysplasia of the right frontal lobe. A periinsular anterior quadrant disconnection (quadrantotomy) was performed. The postoperative period was uneventful, and the patient was in Engel seizure outcome Class I at the 3-year follow-up. A significant cognitive gain was observed during follow-up. Periinsular anterior quadrantotomy may thus represent a safe technique to efficiently treat refractory epilepsy when epileptogenic foci are localized to 1 frontal lobe while preserving residual motor functions.
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- 2018
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65. Preserving normal facial nerve function and improving hearing outcome in large vestibular schwannomas with a combined approach: planned subtotal resection followed by gamma knife radiosurgery.
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Daniel RT, Tuleasca C, George M, Pralong E, Schiappacasse L, Zeverino M, Maire R, and Levivier M
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- Adult, Aged, Cochlear Nerve physiology, Cochlear Nerve surgery, Facial Nerve physiology, Facial Nerve surgery, Female, Humans, Male, Middle Aged, Postoperative Complications etiology, Radiosurgery adverse effects, Hearing, Neuroma, Acoustic surgery, Postoperative Complications prevention & control, Radiosurgery methods
- Abstract
Objective: To perform planned subtotal resection followed by gamma knife surgery (GKRS) in a series of patients with large vestibular schwannoma (VS), aiming at an optimal functional outcome for facial and cochlear nerves., Methods: Patient characteristics, surgical and dosimetric features, and outcome were collected prospectively at the time of treatment and during the follow-up., Results: A consecutive series of 32 patients was treated between July 2010 and June 2016. Mean follow-up after surgery was 29 months (median 24, range 4-78). Mean presurgical tumor volume was 12.5 cm
3 (range 1.47-34.9). Postoperative status showed normal facial nerve function (House-Brackmann I) in all patients. In a subgroup of 17 patients with serviceable hearing before surgery and in which cochlear nerve preservation was attempted at surgery, 16 (94.1%) retained serviceable hearing. Among them, 13 had normal hearing (Gardner-Robertson class 1) before surgery, and 10 (76.9%) retained normal hearing after surgery. Mean duration between surgery and GKRS was 6.3 months (range 3.8-13.9). Mean tumor volume at GKRS was 3.5 cm3 (range 0.5-12.8), corresponding to mean residual volume of 29.4% (range 6-46.7) of the preoperative volume. Mean marginal dose was 12 Gy (range 11-12). Mean follow-up after GKRS was 24 months (range 3-60). Following GKRS, there were no new neurological deficits, with facial and hearing functions remaining identical to those after surgery in all patients. Three patients presented with continuous growth after GKRS, were considered failures, and benefited from the same combined approach a second time., Conclusion: Our data suggest that large VS management, with planned subtotal resection followed by GKRS, might yield an excellent clinical outcome, allowing the normal facial nerve and a high level of cochlear nerve functions to be retained. Our functional results with this approach in large VS are comparable with those obtained with GKRS alone in small- and medium-sized VS. Longer term follow-up is necessary to fully evaluate this approach, especially regarding tumor control.- Published
- 2017
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66. Deep brain stimulation after previous gamma knife thalamotomy of the Vim for essential tremor is feasible! Clinical, electrophysiological and radiological findings.
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Tuleasca C, Pralong E, Najdenovska E, Cuadra MB, Marques JRF, Vingerhoets F, Régis J, Bloch J, and Levivier M
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- Humans, Radiosurgery, Thalamus, Ventral Thalamic Nuclei, Deep Brain Stimulation, Essential Tremor surgery
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- 2017
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67. A New Combined Technique Reducing the Risk of Paraplegia during Thoracoabdominal Aorta Replacement.
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Tozzi P, Pralong E, Gronchi F, and Siniscalchi G
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- Aorta, Thoracic physiopathology, Aortic Aneurysm, Thoracic diagnosis, Aortic Aneurysm, Thoracic physiopathology, Blood Vessel Prosthesis, Blood Vessel Prosthesis Implantation adverse effects, Blood Vessel Prosthesis Implantation instrumentation, Electric Stimulation, Humans, Neuromuscular Monitoring, Paraplegia diagnosis, Paraplegia etiology, Paraplegia physiopathology, Predictive Value of Tests, Replantation, Risk Factors, Spinal Cord Ischemia diagnosis, Spinal Cord Ischemia etiology, Spinal Cord Ischemia physiopathology, Thoracic Arteries surgery, Tibial Nerve, Trauma, Nervous System diagnosis, Trauma, Nervous System etiology, Trauma, Nervous System physiopathology, Treatment Outcome, Workflow, Aorta, Thoracic surgery, Aortic Aneurysm, Thoracic surgery, Blood Vessel Prosthesis Implantation methods, Evoked Potentials, Motor, Intraoperative Neurophysiological Monitoring methods, Paraplegia prevention & control, Spinal Cord Ischemia prevention & control, Trauma, Nervous System prevention & control
- Abstract
Acute spinal cord ischemia during thoracoabdominal aorta replacement is a dreadful complication. Existing tools (motor evoked potential [MEP] and somatosensory evoked potential [SSEP]) do not allow differentiating between central and peripheral paraplegia. Therefore, the surgeon often performs unnecessary reimplantation of intercostal arteries: this is time consuming, and significantly increases bleeding complications. We present a simple technique combining MEP and peripheral compound muscle action potential induced by posterior tibialis nerve stimulation, enabling the surgeon to quickly discriminate between central and peripheral neurologic injury. The surgeon has one more tool to drive in real time the optimal surgical strategy. This strategy guides the decision as to which side branches ought to be reimplanted, thus minimizing the risk of paraplegia., (Georg Thieme Verlag KG Stuttgart · New York.)
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- 2017
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68. Poly-3-hydroxybutyrate strips seeded with regenerative cells are effective promoters of peripheral nerve repair.
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Schaakxs D, Kalbermatten DF, Pralong E, Raffoul W, Wiberg M, and Kingham PJ
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- Animals, Electromyography, Female, Muscles drug effects, Organ Size, Peripheral Nerves drug effects, Peripheral Nerves pathology, Prohibitins, Rats, Sprague-Dawley, Recovery of Function drug effects, Walking, Hydroxybutyrates pharmacology, Nerve Regeneration drug effects, Peripheral Nerves physiology, Polyesters pharmacology
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Peripheral nerve injuries are often associated with loss of nerve tissue and require a graft to bridge the gap. Autologous nerve grafts are still the 'gold standard' in reconstructive surgery but have several disadvantages, such as sacrifice of a functional nerve, neuroma formation and loss of sensation at the donor site. Bioengineered grafts represent a promising approach to address this problem. In this study, poly-3-hydroxybutyrate (PHB) strips were used to bridge a 10 mm rat sciatic nerve gap and their effects on long-term (12 weeks) nerve regeneration were compared. PHB strips were seeded with different cell types, either primary Schwann cells (SCs) or SC-like differentiated adipose-derived stem cells (dASCs) suspended in a fibrin glue matrix. The control group was PHB and fibrin matrix without cells. Functional and morphological properties of the regenerated nerve were assessed using walking track analysis, EMGs, muscle weight ratios and muscle and nerve histology. The animals treated with PHB strips seeded with SCs or dASCs showed significantly better functional ability than the control group. This correlated with less muscle atrophy and greater axon myelination in the cell groups. These findings suggest that the PHB strip seeded with cells provides a beneficial environment for nerve regeneration. Furthermore, dASCs, which are abundant and easily accessible, constitute an attractive cell source for future applications of cell therapy for the clinical repair of traumatic nerve injuries. Copyright © 2015 John Wiley & Sons, Ltd., (Copyright © 2015 John Wiley & Sons, Ltd.)
- Published
- 2017
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69. Deep Brain Stimulation of the Ventroposteromedial (VPM) Thalamus 10 Years after VPM Thalamotomy to Treat a Recurrent Facial Pain.
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Yamgoue Y, Pralong E, Levivier M, and Bloch J
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- Female, Humans, Middle Aged, Monitoring, Intraoperative methods, Recurrence, Time Factors, Treatment Outcome, Deep Brain Stimulation methods, Facial Pain diagnostic imaging, Facial Pain surgery, Ventral Thalamic Nuclei diagnostic imaging, Ventral Thalamic Nuclei surgery
- Abstract
We report the successful treatment of recurrent facial pain by deep brain stimulation (DBS) of the ventroposteromedial thalamic nucleus (VPM-DBS), 10 years after VPM thalamotomy. A 62-year-old woman who suffered from an atypical right-sided trigeminal neuralgia of the V1 and V2 branches was successfully treated a decade ago with a radiofrequency VPM thermocoagulation. Ten years later, the same burning right-sided trigeminal pain progressively recurred and was resistant to medical treatments. A DBS procedure was proposed to the patient aiming to stimulate the vicinity of the preexisting stereotactic lesion. Intraoperatively, the pain relief was immediate at low stimulation intensities. Eleven months later, the patient remains pain free. This case report suggests that DBS targeting an area of the VPM close to the previous stereotactic lesion is possible as a salvage therapy, and can successfully achieve relief of facial pain 10 years after VPM thalamotomy., (© 2016 S. Karger AG, Basel.)
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- 2016
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70. Automatic target validation based on neuroscientific literature mining for tractography.
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Vasques X, Richardet R, Hill SL, Slater D, Chappelier JC, Pralong E, Bloch J, Draganski B, and Cif L
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Target identification for tractography studies requires solid anatomical knowledge validated by an extensive literature review across species for each seed structure to be studied. Manual literature review to identify targets for a given seed region is tedious and potentially subjective. Therefore, complementary approaches would be useful. We propose to use text-mining models to automatically suggest potential targets from the neuroscientific literature, full-text articles and abstracts, so that they can be used for anatomical connection studies and more specifically for tractography. We applied text-mining models to three structures: two well-studied structures, since validated deep brain stimulation targets, the internal globus pallidus and the subthalamic nucleus and, the nucleus accumbens, an exploratory target for treating psychiatric disorders. We performed a systematic review of the literature to document the projections of the three selected structures and compared it with the targets proposed by text-mining models, both in rat and primate (including human). We ran probabilistic tractography on the nucleus accumbens and compared the output with the results of the text-mining models and literature review. Overall, text-mining the literature could find three times as many targets as two man-weeks of curation could. The overall efficiency of the text-mining against literature review in our study was 98% recall (at 36% precision), meaning that over all the targets for the three selected seeds, only one target has been missed by text-mining. We demonstrate that connectivity for a structure of interest can be extracted from a very large amount of publications and abstracts. We believe this tool will be useful in helping the neuroscience community to facilitate connectivity studies of particular brain regions. The text mining tools used for the study are part of the HBP Neuroinformatics Platform, publicly available at http://connectivity-brainer.rhcloud.com/.
- Published
- 2015
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71. [Operative and perioperative aspects of deep brain stimulation].
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Momjian S, Boëx C, Pralong E, Vargas MI, Draganski B, Horvath J, and Bloch J
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- Anesthesia, General methods, Anesthesia, Local methods, Deep Brain Stimulation adverse effects, Electrodiagnosis methods, Humans, Stereotaxic Techniques, Deep Brain Stimulation methods, Movement Disorders therapy, Perioperative Care methods
- Abstract
Deep brain stimulation (DBS) requires the surgical implantation of a system including brain electrodes and impulsion generator(s). The nuclei targeted by the stereotaxic implantation methodology have to be visualized at best by high resolution imaging. The surgical procedure for implanting the electrodes is performed if possible under local anaesthesia to make electro-physiological measurements and to test intra-operatively the effect of the stimulation, in order to optimize the position of the definitive electrode. In a second step, the impulsion generator(s) are implanted under general anaesthesia. DBS for movement disorders has a very good efficacy and a low albeit non-zero risk of serious complications. Complications related to the material are the most common.
- Published
- 2015
72. Bilateral deep brain stimulation: the placement of the second electrode is not necessarily less accurate than that of the first one.
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Sadeghi Y, Pralong E, Knebel JF, Vingerhoets F, Pollo C, Levivier M, and Bloch J
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- Aged, Female, Humans, Male, Middle Aged, Monitoring, Intraoperative methods, Monitoring, Intraoperative standards, Movement Disorders diagnosis, Retrospective Studies, Deep Brain Stimulation instrumentation, Deep Brain Stimulation standards, Electrodes, Implanted standards, Movement Disorders therapy, Subthalamic Nucleus physiology
- Abstract
Background: Deep brain stimulation (DBS) is recognized as an effective treatment for movement disorders. We recently changed our technique, limiting the number of brain penetrations to three per side., Objectives: The first aim was to evaluate the electrode precision on both sides of surgery since we implemented this surgical technique. The second aim was to analyse whether or not the electrode placement was improved with microrecording and macrostimulation., Methods: We retrospectively reviewed operation protocols and MRIs of 30 patients who underwent bilateral DBS. For microrecording and macrostimulation, we used three parallel channels of the 'Ben Gun' centred on the MRI-planned target. Pre- and post-operative MRIs were merged. The distance between the planned target and the centre of the implanted electrode artefact was measured., Results: There was no significant difference in targeting precision on both sides of surgery. There was more intra-operative adjustment of the second electrode positioning based on microrecording and macrostimulation, which allowed to significantly approach the MRI-planned target on the medial-lateral axis., Conclusion: There was more electrode adjustment needed on the second side, possibly in relation with brain shift. We thus suggest performing a single central track with electrophysiological and clinical assessment, with multidirectional exploration on demand for suboptimal clinical responses.
- Published
- 2015
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73. Neurophysiological changes during shortening osteotomies of the spine.
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Schizas C, Pralong E, Debatisse D, and Kulik G
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- Adolescent, Adult, Aged, Aged, 80 and over, Female, Humans, Kyphosis physiopathology, Male, Middle Aged, Osteotomy methods, Thoracic Vertebrae physiopathology, Treatment Outcome, Evoked Potentials, Motor physiology, Kyphosis surgery, Monitoring, Intraoperative methods, Osteotomy adverse effects, Thoracic Vertebrae surgery
- Abstract
Background Context: Kyphotic deformities with sagittal imbalance of the spine can be treated with spinal osteotomies. Those procedures are known to have a high incidence of neurological complications, in particular at the thoracic level. Motor evoked potentials (MEPs) have been widely used in helping to avoid major neurological deficits postoperatively. Previous reports have shown that a significant proportion of such cases present with important transcranial MEP (Tc-MEP) changes during surgery with some of them being predictive of postoperative deficits., Purpose: Our aim was to study Tc-MEP changes in a consecutive series of patients and correlate them with clinical parameters and radiological changes., Study Design/setting: Retrospective case notes study from a prospective patient register., Patient Sample: Eighteen patients undergoing posterior shortening osteotomies (nine at thoracic and nine at lumbar levels) for kyphosis of congenital, degenerative, inflammatory, or post-traumatic origin were included., Outcome Measures: Loss of at least 80% of Tc-MEP signal expressed as the area under the curve percentual change, of at least one muscle., Methods: We studied the relation between outcome measure (80% Tc-MEP loss in at least one muscle group) and amount of posterior vertebral body shortening as well as angular correction measured on computed tomography scans, occurrence of postoperative deficits, intraoperative blood pressure at the time of the osteotomy, and hemoglobin (Hb) change., Results: All patients showed significant Tc-MEP changes. In particular, greater than 80% MEP loss in at least one muscle group was observed in five of nine patients in the thoracic group and four of nine patients in the lumbar group. No surgical maneuver was undertaken as a result of this loss in an effort to improve motor responses other than verifying the stability of the construct and the extent of the decompression. Four patients developed postoperative deficits of radicular origin, three of them recovering fully at 3 months. No relation was found between intraoperative blood pressure, Hb changes, and Tc-MEP changes. Severity of Tc-MEP loss did not correlate with postoperative deficits. Shortening of more than 10 mm was linked to more severe Tc-MEP changes in the thoracic group., Conclusions: Transcranial MEP changes during spinal shortening procedures are common and do not appear to predict severe postoperative deficits. Total loss of Tc-MEP (not witnessed in our series) might require a more drastic approach with possible reversal of the correction and wake-up test., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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74. Interspinous distraction in lumbar spinal stenosis: a neurophysiological perspective.
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Schizas C, Pralong E, Tzioupis C, and Kulik G
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- Aged, Aged, 80 and over, Decompression, Surgical instrumentation, Evoked Potentials, Motor physiology, Female, Humans, Intraoperative Neurophysiological Monitoring methods, Lumbar Vertebrae pathology, Lumbar Vertebrae physiopathology, Male, Middle Aged, Outcome Assessment, Health Care methods, Postoperative Period, Preoperative Period, Prospective Studies, Reproducibility of Results, Severity of Illness Index, Spinal Stenosis pathology, Spinal Stenosis physiopathology, Decompression, Surgical methods, Lumbar Vertebrae surgery, Prostheses and Implants, Spinal Stenosis surgery
- Abstract
Study Design: Prospective neurophysiological study., Objective: To identify and quantify the neurophysiological effects of interspinous distraction during spine surgery for lumbar spinal stenosis (LSS)., Summary of Background Data: Interspinous devices have been introduced as an alternative treatment of LSS in selected patients aiming at obtaining indirect decompression. Nevertheless, there is no data on the immediate neurophysiological effect of distraction., Methods: Thirty patients with LSS undergoing decompression (14 at single level, 16 at multiple levels) were enrolled, resulting in a total of 48 levels to be analyzed. Before decompression, calibrated incremental distraction simulating interspinous device implantation of 8, 10, 12, 14, and 16 mm was performed. Intraoperative motor evoked potentials were acquired before any distraction, during distraction at each incremental value and after bilateral decompression. We evaluated relative changes of motor evoked potentials normalized to hand muscles and related them to the number of affected levels, LSS radiological severity based on the A to D grading, lordosis, and disc height., Results: For single-level disease, 8-mm distraction and open decompression yielded similar improvement in motor evoked potentials not only in levels with morphological grades A or B, but also in levels with morphological grades C or D (i.e., severe or extreme stenosis) (P = 0.32). In contrast, distraction superior to 8 mm was less effective (P ≤ 0.05). In multiple-level stenosis, decompression was significantly more effective than any degree of distraction (P < 0.001). No correlation of those results to disc height or lordosis was observed. Using χ trend test to analyze the effect of distraction, a linear trend favoring moderate over severe stenotic morphology was observed (P = 0.0349)., Conclusion: Interspinous distraction of 8 mm is sufficient to replicate electrophysiological improvements obtained during full decompression even in severe single-level stenosis but not in multilevel disease. Interspinous distraction has therefore an immediately measurable neurophysiological effect., Level of Evidence: 4.
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- 2013
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75. A CT-based study investigating the relationship between pedicle screw placement and stimulation threshold of compound muscle action potentials measured by intraoperative neurophysiological monitoring.
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Kulik G, Pralong E, McManus J, Debatisse D, and Schizas C
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- Adult, Aged, Aged, 80 and over, Bone Screws, Female, Humans, Lumbar Vertebrae diagnostic imaging, Lumbar Vertebrae surgery, Male, Middle Aged, Muscle, Skeletal innervation, Muscle, Skeletal physiology, Sensitivity and Specificity, Spinal Diseases diagnostic imaging, Spinal Fusion instrumentation, Thoracic Vertebrae diagnostic imaging, Thoracic Vertebrae surgery, Action Potentials physiology, Monitoring, Intraoperative methods, Spinal Diseases surgery, Spinal Fusion methods, Tomography, X-Ray Computed methods
- Abstract
Purpose: Neurophysiological monitoring aims to improve the safety of pedicle screw placement, but few quantitative studies assess specificity and sensitivity. In this study, screw placement within the pedicle is measured (post-op CT scan, horizontal and vertical distance from the screw edge to the surface of the pedicle) and correlated with intraoperative neurophysiological stimulation thresholds., Methods: A single surgeon placed 68 thoracic and 136 lumbar screws in 30 consecutive patients during instrumented fusion under EMG control. The female to male ratio was 1.6 and the average age was 61.3 years (SD 17.7). Radiological measurements, blinded to stimulation threshold, were done on reformatted CT reconstructions using OsiriX software. A standard deviation of the screw position of 2.8 mm was determined from pilot measurements, and a 1 mm of screw-pedicle edge distance was considered as a difference of interest (standardised difference of 0.35) leading to a power of the study of 75 % (significance level 0.05)., Results: Correct placement and stimulation thresholds above 10 mA were found in 71 % of screws. Twenty-two percent of screws caused cortical breach, 80 % of these had stimulation thresholds above 10 mA (sensitivity 20 %, specificity 90 %). True prediction of correct position of the screw was more frequent for lumbar than for thoracic screws., Conclusion: A screw stimulation threshold of >10 mA does not indicate correct pedicle screw placement. A hypothesised gradual decrease of screw stimulation thresholds was not observed as screw placement approaches the nerve root. Aside from a robust threshold of 2 mA indicating direct contact with nervous tissue, a secondary threshold appears to depend on patients' pathology and surgical conditions.
- Published
- 2013
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76. Chronic deep brain stimulation in mesial temporal lobe epilepsy.
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Boëx C, Seeck M, Vulliémoz S, Rossetti AO, Staedler C, Spinelli L, Pegna AJ, Pralong E, Villemure JG, Foletti G, and Pollo C
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- Adult, Anticonvulsants therapeutic use, Electrodes, Implanted, Electroencephalography, Epilepsy, Temporal Lobe pathology, Epilepsy, Temporal Lobe psychology, Female, Follow-Up Studies, Hippocampus pathology, Humans, Long-Term Care, Magnetic Resonance Imaging, Male, Memory physiology, Middle Aged, Neuropsychological Tests, Neurosurgical Procedures, Sclerosis, Seizures epidemiology, Seizures prevention & control, Tomography, Emission-Computed, Single-Photon, Treatment Outcome, Deep Brain Stimulation psychology, Epilepsy, Temporal Lobe therapy
- Abstract
The objective of this study was to evaluate the efficiency and the effects of changes in parameters of chronic amygdala-hippocampal deep brain stimulation (AH-DBS) in mesial temporal lobe epilepsy (TLE). Eight pharmacoresistant patients, not candidates for ablative surgery, received chronic AH-DBS (130 Hz, follow-up 12-24 months): two patients with hippocampal sclerosis (HS) and six patients with non-lesional mesial TLE (NLES). The effects of stepwise increases in intensity (0-Off to 2 V) and stimulation configuration (quadripolar and bipolar), on seizure frequency and neuropsychological performance were studied. The two HS patients obtained a significant decrease (65-75%) in seizure frequency with high voltage bipolar DBS (≥1 V) or with quadripolar stimulation. Two out of six NLES patients became seizure-free, one of them without stimulation, suggesting a microlesional effect. Two NLES patients experienced reductions of seizure frequency (65-70%), whereas the remaining two showed no significant seizure reduction. Neuropsychological evaluations showed reversible memory impairments in two patients under strong stimulation only. AH-DBS showed long-term efficiency in most of the TLE patients. It is a valuable treatment option for patients who suffer from drug resistant epilepsy and who are not candidates for resective surgery. The effects of changes in the stimulation parameters suggest that a large zone of stimulation would be required in HS patients, while a limited zone of stimulation or even a microlesional effect could be sufficient in NLES patients, for whom the importance of the proximity of the electrode to the epileptogenic zone remains to be studied. Further studies are required to ascertain these latter observations., (Copyright © 2011 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2011
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77. [Periinsular hemispherotomy: surgical technique, intraoperative EEG monitoring and results on seizure outcome].
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Pollo C, Debatisse D, Pralong E, and Levivier M
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- Adolescent, Adult, Amygdala surgery, Child, Child, Preschool, Corpus Callosum surgery, Epilepsy surgery, Female, Fornix, Brain surgery, Hippocampus surgery, Humans, Infant, Magnetic Resonance Imaging, Male, Monitoring, Intraoperative, Postoperative Complications epidemiology, Treatment Outcome, Cerebral Cortex pathology, Cerebral Cortex surgery, Electroencephalography, Neurosurgical Procedures methods, Seizures surgery
- Abstract
Peri-insular hemispherotomy is a surgical technique used in the treatment of drug-resistant epilepsy of hemispheric origin. It is based on the exposure of insula and semi-circular sulci, providing access to the lateral ventricle through a supra- and infra-insular window. From inside the ventricle, a parasagittal callosotomy is performed. The basal and medial portion of the frontal lobe is isolated. Projections to the anterior commissure are interrupted at the time of amygdala resection. The hippocampal tail and fimbria-fornix are disrupted posteriorly. We report our experience of 18 cases treated with this approach. More than half of them presented with congenital epilepsy. Neuronavigation was useful in precisely determining the center and extent of the craniotomy, as well as the direction of tractotomies and callosotomy, allowing minimal exposure and blood loss. Intra-operative monitoring by scalp EEG on the contralateral hemisphere was used to follow the progression of the number of interictal spikes during the disconnection procedure. Approximately 90% of patients were in Engel's Class I. We observed one case who presented with transient postoperative neurological deterioration probably due to CSF overdrainage and documented one case of incomplete disconnection in a patient presenting with hemimegalencephaly who needed a second operation. We observed a good correlation between a significant decrease in the number of spikes at the end of the procedure and seizure outcome. Peri-insular hemispherotomy provides a functional disconnection of the hemisphere with minimal resection of cerebral tissue. It is an efficient technique with a low complication rate. Intra-operative EEG monitoring might be used as a predictive factor of completeness of the disconnection and consequently, seizure outcome.
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- 2008
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78. Opposite effects of internal globus pallidus stimulation on pallidal neurones activity.
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Pralong E, Pollo C, Villemure JG, and Debatisse D
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- Brain Mapping, Child, Dystonic Disorders physiopathology, Dystonic Disorders therapy, Electrodes, Implanted, Electroencephalography, Humans, Lesch-Nyhan Syndrome therapy, Male, Muscle Hypotonia physiopathology, Muscle Hypotonia therapy, Neural Inhibition physiology, Neurons physiology, Self Mutilation physiopathology, Self Mutilation therapy, Signal Processing, Computer-Assisted, Spasm physiopathology, Spasm therapy, Synaptic Transmission physiology, Theta Rhythm, Treatment Outcome, Deep Brain Stimulation, Globus Pallidus physiopathology, Lesch-Nyhan Syndrome physiopathology
- Abstract
Besides clinical efficacy, the mechanisms of action of deep brain stimulation (DBS) are still debated. To shed light on this complex issue, we have taken the opportunity to record the response of globus pallidus internus (GPi) neurones to 100 Hz stimulations in a case of Lesch-Nyhan syndrome (LNS) where four pallidal electrodes were implanted. Three types of response were observed, 2/19 neurones were unaffected by DBS. About 7/19 neurones were inhibited during DBS stimulation and 10/19 neurones were excited during DBS stimulation. Both effects ceased when DBS was turned off. Inhibited neurones were situated lower that exited ones on the trajectory (1.25 and 4.65 mm above the center of GPi respectively). These observations suggest that locally DBS induces a reversible inhibition of neurone firing rate while at the same time distantly exciting the main afferents to and/or efferents from the GPi. Both actions would result in a strong GPi inhibition that does not preclude increased outflow from the GPi., (2007 Movement Disorder Society)
- Published
- 2007
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79. Localization of electrodes in the subthalamic nucleus on magnetic resonance imaging.
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Pollo C, Vingerhoets F, Pralong E, Ghika J, Maeder P, Meuli R, Thiran JP, and Villemure JG
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- Aged, Female, Humans, Imaging, Three-Dimensional, Male, Middle Aged, Parkinson Disease therapy, Septal Nuclei pathology, Algorithms, Artifacts, Deep Brain Stimulation instrumentation, Electrodes, Implanted, Magnetic Resonance Imaging, Parkinson Disease pathology, Subthalamic Nucleus pathology
- Abstract
Object: The authors describe a new method of localizing electrodes on magnetic resonance (MR) images and focus on the positions of both the most efficient contact and the electrode related to the MR imaging target., Methods: Thirty-one patients who had undergone bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) were included in this study. Target coordinates were calculated in the anterior commissure-posterior commissure referential. A study of the correlation between the artifact and the related contact allowed one to deduce the contact position from the identification of the distal artifact on MR imaging. The best stimulation point corresponded with the contact resulting in the best Unified Parkinson's Disease Rating Scale (UPDRS) motor score improvement. It was compared (Student t-test) with the dorsal margin of the STN (DM STN), which was determined electrophysiologically. The distance between the target and the electrode was calculated individually in each axis. The best stimulation point was located at anteroposterior -2.34 +/- 1.63 mm, lateral 12.04 +/- 1.62 mm, and vertical -2.57 +/- 1.68 mm. This point was not significantly different from the DM STN (p < 0.05). The postoperative UPDRS motor score was 28.07 +/- 12.16, as opposed to the preoperative score of 46.27 +/- 13.89. The distance between the expected and actual target in the x- and y-axes was 1.34 +/- 1.02 and 1.03 +/- 0.76 mm, respectively. In the z-axis, 39.7% of the distal contacts were located proximal to the target., Conclusions: This approach proposed for the localization of the electrodes on MR imaging shows that DBS is most effective in the dorsal and lateral part of the STN and indicates that the DBS electrode can be located more proximally than originally expected because of the caudal brain shift that may occur during the implantation procedure.
- Published
- 2007
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80. Quality index for the quantification of the information recorded along standard microelectrode tracks to the subthalamic nucleus in parkinsonian patients.
- Author
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Pralong E, Villemure JG, Bloch J, Pollo C, Daniels RT, Ghika J, Vingerhoets F, Tetreault MH, and Debatisse D
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- Electrophysiology, Humans, Magnetic Resonance Imaging, Microelectrodes, Monitoring, Intraoperative, Neurons physiology, Reproducibility of Results, Thalamus physiopathology, Parkinson Disease physiopathology, Subthalamic Nucleus physiopathology
- Abstract
Objective: To quantify the usefulness of the neuronal activity recorded on a standard microelectrode track to the subthalamic nucleus (STN) for the determination of the transition between the thalamus and the STN., Methods: The study is based on analysis of 689 extracelullar single units recorded on 70 tracks passing through the thalamus and the STN. Using four neuron parameters that were correlated with electrode depth, a quality index (QI) for each track was computed and compared with the subjective assessment by the electrophysiologist of the track quality., Results: Subjectively, the transition between the thalamus and the STN was detected in 49 tracks (usual track) and not detected on 21 tracks (unusual tracks). Objectively, spike frequency, cell burst index (BI), signal relative root mean square (RMS) and spike relative amplitude were correlated with electrode depth and used to compute track QI. The average QI index of usual and unusual tracks was 0.25 +/- 0.9 and 0.85 +/- 0.15 (mean +/- confidence interval at P < 0.001), respectively. In 20 patients, QI correlates with post-operative measurement of electrode length in the STN., Conclusion: These results demonstrate that simple statistical analysis taking into account the variation of single-unit characteristics with electrode depth can discriminate between useful and useless tracks for the determination of the STN localisation.
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- 2004
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81. Recording of ventral posterior lateral thalamus neuron response to contact heat evoked potential in patient with neurogenic pain.
- Author
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Pralong E, Pollo C, Bloch J, Villemure JG, Daniel RT, Tétreault MH, and Debatisse D
- Subjects
- Action Potentials physiology, Action Potentials radiation effects, Humans, Magnetic Resonance Imaging, Male, Middle Aged, Pain pathology, Pain physiopathology, Electric Stimulation Therapy, Evoked Potentials physiology, Hot Temperature therapeutic use, Pain Management, Thalamus pathology
- Abstract
Microrecording of single unit response to contact heat-evoked potential (CHEP) were performed in right ventral posterior lateral (VPL) thalamus during deep brain stimulation (DBS) surgery in a patient with chronic neurogenic pain. In our patient, neurons (n = 10) recorded in the ventral thalamus fired at a higher rate of 40 Hz compared to neurons recorded in Parkinsonian patients (24 Hz). Contact heat was applied by a fast heating and cooling probe of 5 cm2 area on the dermatome C6 territory of the left hand. One out of four thalamic cells located in the VPL responded repetitively 325 ms after the peak temperature was reached with a burst of action potential, suggesting A-delta fibre activation. This observation supports the use of CHEP for mapping nociceptive neurons location during DBS surgery for intractable pain.
- Published
- 2004
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82. Effect of deep brain stimulation of GPI on neuronal activity of the thalamic nucleus ventralis oralis in a dystonic patient.
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Pralong E, Debatisse D, Maeder M, Vingerhoets F, Ghika J, and Villemure JG
- Subjects
- Adult, Anesthesia, Intravenous, Anesthetics, Intravenous, Dystonia therapy, Electric Stimulation, Electrodes, Implanted, Electrophysiology, Extracellular Space physiology, Humans, Magnetic Resonance Imaging, Male, Propofol, Stereotaxic Techniques, Suicide, Dystonia physiopathology, Globus Pallidus physiology, Neurons physiology, Ventral Thalamic Nuclei cytology, Ventral Thalamic Nuclei physiology
- Abstract
Objective: To record the possible effect of acute deep brain stimulation (DBS) of the globus pallidus internus (GPI) on the neuronal activity of the ventralis oralis anterior (VOA) nucleus of the thalamus., Methods: Under general propofol anaesthesia, extracelullar single unit recordings were performed in VOA of a post-anoxic dystonic patient previously implanted with GPI located electrodes for chronic DBS., Results: Neurons recorded in the VOA could be classified in two cell subpopulations: a high firing rate (16.5 Hz) and low burst index (BI; 15.6) type and a low firing rate (5.5 Hz) and high BI (35.6) type. GPI electrical stimulation reduced the frequency and increased the BI of the high firing rate cells while leaving the other cell type unchanged., Conclusion: These results demonstrate that pallidal DBS is able to inhibit a subpopulation of motor thalamic cells and question the pathophysiological model of dystonia based on a low firing rate of GPI cells.
- Published
- 2003
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83. Activation of metabotropic glutamate 5 and NMDA receptors underlies the induction of persistent bursting and associated long-lasting changes in CA3 recurrent connections.
- Author
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Stoop R, Conquet F, Zuber B, Voronin LL, and Pralong E
- Subjects
- Animals, Entorhinal Cortex cytology, Entorhinal Cortex drug effects, Entorhinal Cortex physiology, Excitatory Amino Acid Antagonists pharmacology, Excitatory Postsynaptic Potentials drug effects, Excitatory Postsynaptic Potentials physiology, Female, GABA Antagonists pharmacology, Hippocampus cytology, Hippocampus drug effects, In Vitro Techniques, Interneurons drug effects, Interneurons physiology, Long-Term Potentiation drug effects, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Neural Inhibition drug effects, Neural Inhibition physiology, Patch-Clamp Techniques, Protein Synthesis Inhibitors pharmacology, Pyramidal Cells drug effects, Pyramidal Cells physiology, Receptor, Metabotropic Glutamate 5, Receptors, Metabotropic Glutamate deficiency, Receptors, Metabotropic Glutamate genetics, Receptors, N-Methyl-D-Aspartate antagonists & inhibitors, Hippocampus physiology, Long-Term Potentiation physiology, Neuronal Plasticity physiology, Receptors, Metabotropic Glutamate metabolism, Receptors, N-Methyl-D-Aspartate metabolism
- Abstract
The aim of this study was to describe the induction and expression mechanisms of a persistent bursting activity in a horizontal slice preparation of the rat limbic system that includes the ventral part of the hippocampus and the entorhinal cortex. Disinhibition of this preparation by bicuculline led to interictal-like bursts in the CA3 region that triggered synchronous activity in the entorhinal cortex. Washout of bicuculline after a 1 hr application resulted in a maintained production of hippocampal bursts that continued to spread to the entorhinal cortex. Separation of CA3 from the entorhinal cortex caused the activity in the latter to become asynchronous with CA3 activity in the presence of bicuculline and disappear after washout; however, in CA3, neither the induction of bursting nor its persistence were affected. Associated with the CA3 persistent bursting, a strengthening of recurrent collateral excitatory input to CA3 pyramidal cells and a decreased input to CA3 interneurons was found. Both the induction of the persistent bursting and the changes in synaptic strength were prevented by antagonists of metabotropic glutamate 5 (mGlu5) or NMDA receptors or protein synthesis inhibitors and did not occur in slices from mGlu5 receptor knock-out mice. The above findings suggest potential synaptic mechanisms by which the hippocampus switches to a persistent interictal bursting mode that may support a spread of interictal-like bursting to surrounding temporal lobe regions.
- Published
- 2003
84. Electrophysiological localization of the subthalamic nucleus in parkinsonian patients.
- Author
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Pralong E, Ghika J, Temperli P, Pollo C, Vingerhoets F, and Villemure JG
- Subjects
- Action Potentials, Electrophysiology, Humans, Neurons physiology, Reaction Time, Thalamus physiopathology, Brain Mapping methods, Parkinsonian Disorders physiopathology, Subthalamic Nucleus physiopathology
- Abstract
Deep brain stimulation of the subthalamic nucleus (STN) is becoming the procedure of choice to reduce symptoms of Parkinson's disease such as rigidity, akinesia and tremor. We present here a series of electrophysiological recordings performed in 34 patients along a standardized electrode trajectory. Neuronal activity along the trajectory consists of a first heterogeneous population of thalamic cells with a mean frequency of 24.8+/-1.4 Hz followed by a silent zone and a second population of STN neurones with a significantly higher spiking frequency (P<0.001) of 42.3+/-1.8 Hz. This study confirms previous findings and suggests that rapid measurement of neuronal spiking frequency and burst index is sufficient to determine precisely the vertical position of the STN.
- Published
- 2002
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85. Functional connections and epileptic spread between hippocampus, entorhinal cortex and amygdala in a modified horizontal slice preparation of the rat brain.
- Author
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Stoop R and Pralong E
- Subjects
- Action Potentials drug effects, Action Potentials physiology, Amygdala drug effects, Amygdala pathology, Animals, Bicuculline pharmacokinetics, Denervation adverse effects, Disease Models, Animal, Entorhinal Cortex drug effects, Entorhinal Cortex pathology, Epilepsy chemically induced, Epilepsy pathology, Excitatory Amino Acid Antagonists pharmacology, Female, Hippocampus drug effects, Hippocampus pathology, Male, Neural Pathways drug effects, Neural Pathways pathology, Neurons drug effects, Neurons pathology, Neurons physiology, Rats, Rats, Inbred Strains, Receptors, N-Methyl-D-Aspartate antagonists & inhibitors, Receptors, N-Methyl-D-Aspartate drug effects, Receptors, N-Methyl-D-Aspartate metabolism, Synapses drug effects, Synapses physiology, Synaptic Transmission drug effects, Synaptic Transmission physiology, Time Factors, Amygdala physiopathology, Entorhinal Cortex physiopathology, Epilepsy physiopathology, Hippocampus physiopathology, Neural Pathways physiopathology
- Abstract
The hippocampus, the entorhinal cortex and the amygdala are interconnected structures of the limbic system that are implicated in memory and emotional behaviour. They demonstrate synaptic plasticity and are susceptible to development of temporal lobe epilepsy, which may lead to emotional and psychological disturbances. Their relative anatomical disposition has limited the study of neurotransmission and epileptic spread between these three regions in previous in vitro preparations. Here we describe a novel, modified-horizontal slice preparation that includes in the same plane the hippocampus, entorhinal cortex and amygdala. We found that, following application of bicuculline, each region in our preparation could generate spontaneous bursts that resembled epileptic interictal spikes. This spontaneous activity initiated in the hippocampal CA3/2 region, from where it propagated and controlled the activity in the entorhinal cortex and the amygdala. We found that this spontaneous bursting activity could spread via two different pathways. The first pathway comprises the well-known subiculum-entorhinal cortex-perirhinal cortex-amygdala route. The second pathway consists of a direct connection between the CA1 region and perirhinal cortex, through which the hippocampal bursting activity can spread to the amygdala while bypassing the entorhinal cortex. Thus, our experiments provide a new in vitro model of initiation and spread of epileptic-like activity in the ventral part of the limbic system, which includes a novel, fast and functional connection between the CA1 region and perirhinal cortex.
- Published
- 2000
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86. Noradrenaline modulates glutamate-mediated neurotransmission in the rat basolateral amygdala in vitro.
- Author
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Ferry B, Magistretti PJ, and Pralong E
- Subjects
- Amygdala cytology, Amygdala drug effects, Amygdala physiology, Animals, Electric Stimulation, Entorhinal Cortex physiology, In Vitro Techniques, Membrane Potentials drug effects, Neurons drug effects, Neurons physiology, Rats, Reaction Time, Synapses drug effects, gamma-Aminobutyric Acid physiology, Glutamic Acid physiology, Norepinephrine pharmacology, Synaptic Transmission drug effects
- Abstract
The entorhinal cortex and the amygdala are interconnected structures of the limbic system in which paroxysmal activity occurs during temporal lobe epilepsy. Conflicting evidence shows that noradrenaline (i) inhibits the spreading to other parts of the limbic system of paroxysmal activity generated in the amygdala or the entorhinal cortex, but also (ii) increases glutamatergic transmission in the basolateral amygdala. Given our previous work on the inhibitory effect of noradrenaline on entorhinal cortex neurons, we developed an in vitro slice preparation to study the synaptic transmission in the basolateral amygdala and its modulation by noradrenaline. Noradrenaline reduced the fast excitatory postsynaptic potential (EPSP) by approximately 40% at 100 microM and the slow EPSP by approximately 50% at 50 microM. A similar effect was obtained with the alpha2-agonist UK 14304 at 100 and 50 microM respectively. In contrast, the beta-agonist isoproterenol increased the fast EPSP by approximately 40% at 100 microM and the slow EPSP by approximately 20% at 50 microM. Accordingly, the effect of noradrenaline on the EPSPs was blocked by the alpha2-antagonist yohimbine (10 microM) but not by the alpha1-antagonist prazosine (10 microM) and the beta-antagonist propranolol (10 microM). Noradrenaline (50-100 microM) was ineffective on most (14/16) of the isolated inhibitory postsynaptic potentials (IPSPs). These experiments provide evidence that noradrenaline inhibits the excitatory synaptic response of basolateral amygdala neurons. A pharmacological analysis revealed that the noradrenergic modulation of the excitatory transmission in the basolateral amygdala can be dissected into a predominant alpha2-adrenoreceptor-mediated inhibition and a beta-adrenoreceptor-mediated excitation.
- Published
- 1997
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87. Noradrenaline increases K-conductance and reduces glutamatergic transmission in the mouse entorhinal cortex by activation of alpha 2-adrenoreceptors.
- Author
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Pralong E and Magistretti PJ
- Subjects
- Animals, Dose-Response Relationship, Drug, Membrane Potentials drug effects, Mice, Mice, Inbred Strains, Potassium pharmacology, Yohimbine pharmacology, Entorhinal Cortex drug effects, Glutamic Acid drug effects, Glutamic Acid metabolism, Norepinephrine pharmacology, Potassium Channels drug effects, Receptors, Adrenergic, alpha-2 drug effects
- Abstract
The entorhinal cortex is a gateway to the hippocampus; it receives inputs from several cortical associative areas as well as subcortical areas. Since there is evidence showing that noradrenaline reduces the epileptic activity generated in the entorhinal cortex, we have examined the action of noradrenaline in the superficial layer of the entorhinal cortex, which is the main source of afferents to the hippocampus. In a previous study we showed that noradrenaline hyperpolarized layer II entorhinal cortex neurons and reduced global synaptic transmission via alpha 2-adrenoreceptors. Here we present a detailed analysis of the effect of noradrenaline on membrane resistance and on the pharmacologically isolated postsynaptic potentials in layer II entorhinal cortex neurons of mice. Noradrenaline (50 microM) hyperpolarized most layer II entorhinal cortex neurons. This hyperpolarization corresponded to an outward current with a reversal potential following the Nernst equilibrium potential for potassium. The hyperpolarizing effect of noradrenaline was blocked by 10 microM yohimbine. These observations suggest that noradrenaline activates a potassium conductance via an alpha 2-adrenoreceptor. Noradrenaline (10-50 microM) reversibly reduced the amplitude of the pharmacologically isolated excitatory potentials mediated by both NMDA and alpha-amino-3-hydroxy-5-methyl-isoxazole-propionic acid (AMPA) receptors, the former being more strongly affected. Again this effect was blocked by 10 microM yohimbine. In contrast, GABAA-mediated synaptic transmission was virtually unaffected by noradrenaline. Thus, noradrenaline appears to strongly inhibit the glutamate-mediated synaptic transmission in the entorhinal cortex without affecting inhibitory post-synaptic potentials. These observations suggest that alpha 2-adrenergic receptor agonists may exert a beneficial effect in the control of hyperexcitability in temporal lobe epilepsy.
- Published
- 1995
- Full Text
- View/download PDF
88. Noradrenaline reduces synaptic responses in normal and tottering mouse entorhinal cortex via alpha 2 receptors.
- Author
-
Pralong E and Magistretti PJ
- Subjects
- Adrenergic alpha-2 Receptor Agonists, Adrenergic alpha-2 Receptor Antagonists, Animals, Electrophysiology, Epilepsy physiopathology, In Vitro Techniques, Membrane Potentials drug effects, Mice, Mice, Inbred C57BL, Mice, Neurologic Mutants, Receptors, AMPA drug effects, Receptors, N-Methyl-D-Aspartate drug effects, Synaptic Transmission drug effects, Entorhinal Cortex drug effects, Norepinephrine pharmacology, Receptors, Adrenergic, alpha-2 drug effects, Synapses drug effects
- Abstract
The effects of noradrenaline (NA) on synaptic responses in layer II of the entorhinal cortex (EC) were studied in normal and spontaneously epileptic mutant mice tottering using intracellular recording in a slice preparation. Neither the membrane properties of neurones nor the responses to NA differed between normal and tottering mice. NA (50 microM) hyperpolarized most (29/54) of the neurones via alpha 2 adrenergic receptors. Synaptic responses of EC neurones were complex. NA (10-100 microM) reduced all the components of the synaptic response in a concentration-dependent and reversible manner. The pharmacological properties of the inhibitory effect of NA were characterised and quantified on one component of the complex synaptic response, the fast excitatory postsynaptic potential. The effect of NA was mimicked by the alpha 2 agonist UK 14,304 and blocked by the alpha 2 antagonist yohimbine. It is concluded that NA can inhibit via an alpha 2 receptor-mediated action synaptic responses in the superficial layers of the EC.
- Published
- 1994
- Full Text
- View/download PDF
89. 3-Phenyl-4-hydroxyquinolin-2(1H)-ones: potent and selective antagonists at the strychnine-insensitive glycine site on the N-methyl-D-aspartate receptor complex.
- Author
-
McQuaid LA, Smith EC, Lodge D, Pralong E, Wikel JH, Calligaro DO, and O'Malley PJ
- Subjects
- Animals, Binding Sites, Glycine metabolism, Rats, Structure-Activity Relationship, Glycine antagonists & inhibitors, Quinolones pharmacology, Receptors, N-Methyl-D-Aspartate drug effects, Strychnine pharmacology
- Published
- 1992
- Full Text
- View/download PDF
90. Specificity and potency of N-methyl-D-aspartate glycine site antagonists and of mephenesin on the rat spinal cord in vitro.
- Author
-
Pralong E, Millar JD, and Lodge D
- Subjects
- Animals, Binding Sites, Ibotenic Acid analogs & derivatives, Ibotenic Acid pharmacology, Indoles pharmacology, Kynurenic Acid analogs & derivatives, Kynurenic Acid pharmacology, Pyrrolidinones pharmacology, Quinoxalines pharmacology, Rats, alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid, Glycine, Mephenesin pharmacology, N-Methylaspartate antagonists & inhibitors, Receptors, N-Methyl-D-Aspartate drug effects, Spinal Cord drug effects
- Abstract
The potency, specificity and reversibility of various presumed glycine site N-methyl-D-aspartate (NMDA) antagonists was studied on neonatal rat spinal cord using the grease gap technique. 5,7-Dichlorokynurenate was the most potent and specific glycine site antagonist among the compounds tested. On the other hand mephenesin was a weak non-specific excitatory amino acid (EAA) antagonist; reduction of the response to NMDA was not reversed by D-serine. The EAA antagonist properties of mephenesin could explain its mode of action at the cellular level. The lack of effect of D-serine alone suggests that in our experimental conditions glycine sites on spinal neurones are occupied by an endogenous ligand.
- Published
- 1992
- Full Text
- View/download PDF
91. Prostaglandin photoaffinity probes: synthesis and binding affinity of an azide-substituted 17-phenyl PGE2 prostaglandin.
- Author
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Kawada K, Pralong E, Vesin MF, Fitz TA, and Watt DS
- Subjects
- Affinity Labels metabolism, Animals, Binding Sites, Binding, Competitive, Chickens, Dinoprostone chemical synthesis, Molecular Structure, Photochemistry, Affinity Labels chemical synthesis, Dinoprostone analogs & derivatives, Dinoprostone metabolism
- Published
- 1991
92. PGE2 synthesis in chick spinal cord and high affinity PGE2 receptors on motoneurons.
- Author
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Vesin MF, Pralong E, and Droz B
- Subjects
- Animals, Chickens, Meninges metabolism, Receptors, Prostaglandin E, Dinoprostone biosynthesis, Motor Neurons chemistry, Receptors, Prostaglandin analysis, Spinal Cord metabolism
- Published
- 1991
93. Prostaglandin E2 Receptors in the Chicken Spinal Cord: 1. Biochemical Characterization.
- Author
-
Pralong E, Vesin MF, and Droz B
- Abstract
Prostaglandins (PGs) are neuroactive substances which act in the vicinity of their site of synthesis through receptors coupled to G-proteins. Since large amounts of PGE2 can be synthesized by chicken spinal cord, binding sites for PGE2 were looked for in various cell fractions of spinal cord. In the 17 000 g pellet incubated with 0.3 nM [3H]PGE2, 70% of ligand was specifically bound. Two types of PGE2 binding site were characterized (i) high affinity, low capacity binding sites (KD1 1.34 nM, Bmax1 34.5 fmol/mg prot); (ii) low affinity, high capacity binding sites (KD2 2.23 microM, Bmax2 13.2 pmol/mg prot). The high affinity binding sites fulfil several requirements for being receptors to PGE2: (i) since the KD1 is increased in the presence of the GTP analogue, Gpp(NH)p, these binding sites would be regulated by a G-protein; (ii) a desensitization was obtained by an excess of unlabelled PGE2 and reversed by Gpp(NH)p; (iii) the competition experiments between PGE2 and various prostanoids pointed to PGE2 receptors such as EP2 or EP3. The receptor characteristics of the low-affinity binding sites were not investigated. Hence, our results support the presence of two types of PGE2 binding site in the chicken spinal cord; a high affinity site, which corresponds to a PGE2 receptor responding to nanomolar concentrations and a low affinity site sensitive to micromolar concentrations of PGE2.
- Published
- 1990
- Full Text
- View/download PDF
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