Rôle du controle inhibiteur dans le traitement des informations sensorielles vestibulaires au niveau des voies primaires afférentes et au niveau des voies secondaires commisurales

PARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Caractérisation morphologique du larynx de l'adulte en imagerie 3D (morphométrie et endoscopie virtuelle)

BREST-BU Médecine-Odontologie (290192102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Differential inhibitory control of semicircular canal nerve afferent-evoked inputs in second-order vestibular neurons by glycinergic and GABAergic circuits.

Labyrinthine nerve-evoked monosynaptic excitatory postsynaptic potentials (EPSPs) in second-order vestibular neurons (2 degrees VN) sum with disynaptic inhibitory postsynaptic potentials (IPSPs) that originate from the thickest afferent fibers of the same nerve branch and are mediated by neurons in the ipsilateral vestibular nucleus. Pharmacological properties of the inhibition and the interaction with the afferent excitation were studied by recording monosynaptic responses of phasic and tonic 2 degrees VN in an isolated frog brain after electrical stimulation of individual semicircular canal nerves. Specific transmitter antagonists revealed glycine and GABA(A) receptor-mediated IPSPs with a disynaptic onset only in phasic but not in tonic 2 degrees VN. Compared with GABAergic IPSPs, glycinergic responses in phasic 2 degrees VN have larger amplitudes and a longer duration and reduce early and late components of the afferent nerve-evoked subthreshold activation and spike discharge. The difference in profile of the disynaptic glycinergic and GABAergic inhibition is compatible with the larger number of glycinergic as opposed to GABAergic terminal-like structures on 2 degrees VN. The increase in monosynaptic excitation after a block of the disynaptic inhibition in phasic 2 degrees VN is in part mediated by a N-methyl-d-aspartate receptor-activated component. Although inhibitory inputs were superimposed on monosynaptic EPSPs in tonic 2 degrees VN as well, the much longer latency of these IPSPs excludes a control by short-latency inhibitory feed-forward side-loops as observed in phasic 2 degrees VN. The differential synaptic organization of the inhibitory control of labyrinthine afferent signals in phasic and tonic 2 degrees VN is consistent with the different intrinsic signal processing modes of the two neuronal types and suggests a co-adaptation of intrinsic membrane properties and emerging network properties

Restricted Neural Plasticity in Vestibulospinal Pathways after Unilateral Labyrinthectomy as the Origin for Scoliotic Deformations

International audienceAdolescent idiopathic scoliosis in humans is often associated with vestibulomotor deficits. Compatible with a vestibular origin, scoliotic deformations were provoked in adult Xenopus frogs by unilateral labyrinthectomy (UL) at larval stages. The aquatic ecophysiology and absence of body-weight-supporting limb proprioceptive signals in amphibian tadpoles as a potential sensory substitute after UL might be the cause for a persistent asymmetric descending vestibulospinal activity. Therefore, peripheral vestibular lesions in larval Xenopus were used to reveal the morphophysiological alterations at the cellular and network levels. As a result, spinal motor nerves that were modulated by the previously intact side before UL remained permanently silent during natural vestibular stimulation after the lesion. In addition, retrograde tracing of descending pathways revealed a loss of vestibular neurons on the ipsilesional side with crossed vestibulospinal projections. This loss facilitated a general mass imbalance in descending premotor activity and a permanent asymmetric motor drive to the axial musculature. Therefore, we propose that the persistent asymmetric contraction of trunk muscles exerts a constant, uncompensated differential mechanical pull on bilateral skeletal elements that enforces a distortion of the soft cartilaginous skeletal elements and bone shapes. This ultimately provokes severe scoliotic deformations during ontogenetic development similar to the human syndrome

An uncommon cause of allergic fungal sinusitis: Rhizopus oryzae.

International audienceWe report what we believe is the first case of allergic fungal rhinosinusitis (AFRS) caused by the fungus Rhizopus oryzae. Our patient was a 32-year-old woman who presented with unilateral nasal polyps and chronic nasal dysfunction. Computed tomography of the sinuses detected left-sided pansinusitis and bone erosion. T2-weighted magnetic resonance imaging demonstrated a signal void that suggested the presence of a fungal infection. The patient underwent unilateral ethmoidectomy. Histologic examination of the diseased tissue identified allergic mucin with 70% eosinophils and no fungal hyphae. Mycologic culture detected R oryzae. After a short period of improvement, the patient experienced a recurrence, which was confirmed by radiology. A second surgery was performed, and the same fungal hyphae were found in the mucus and on culture, which led us to suspect AFRS. Since no IgE test for R oryzae was available, we developed a specific immunologic assay that confirmed the presence of specific IgG, which identified a high degree of immunologic reaction against our homemade R oryzae antigens. With a long course of systemic antifungal treatment, the patient's symptoms resolved and no recurrence was noted at 5 years of follow-up

Postoperative Hemorrhage after Transoral Oropharyngectomy for Cancer of the Lateral Oropharynx

International audienc

Early Unilateral Laryngeal Paralysis After Pulmonary Resection With Mediastinal Dissection for Cancer

International audienceObjective : To document the symptoms, evolution, treatment decision and outcome in a large series of patients with unilateral laryngeal paralysis after mediastinal lymph node dissection and pulmonary resection for cancer. Methods : Retrospective series based on an inception cohort of 122 patients consecutively managed at a single institution. Treatement of the ULNP relied on isolated speech therapy in 38 patients and surgical medialisation of the paralysed vocal cord in 83 patients (37 intracordal injection of autologous fat and 46 type I thyroplasty with implant insertion). In one patient a total laryngectomy was performed. Duration of follow varied from 1-118 month. 94 patients had a minimum of 6 months of follow or were followed until either death or recovery of motion of the paralysed vocal cord occured. Results : Symptoms included swallowing impairment and dysphonia noted in 54.4 % and 99.2 % of patients, respectively. Recovery of motion of the paralysed vocal cord, noted in 25.9 % of patients referred before the sixth month after lung surgery, never occurred past this month and/or if the inferior laryngeal or Xth cranial nerves had been transected at time of lung surgery. In univariate analysis, a surgical medialisation of the paralysed vocal cord was statistically more likely to be performed in patients with swallowing impairment, severe dysphonia or paralysis of the left hemilarynx. When performed, medialisation of the paralysed larynx, resulted in an overall 96.3 % and 98,4 % improvement rate for dysphonia and swallowing impairment, repectively. Conclusions : Such results pledge for a close relationship between the thoracic and head and neck surgeon in patients with cancer amenable to lung resection with mediastinal lymph node dissection in an attempt to avoid the major complications related to aspiration and to improve the quality of life of this population