Etude des canaux semi-circulaires verticaux par l'enregistrement du réflexe vestibulo-oculaire

Des patients présentant une instabilité invalidante associée à un nystagmus positionnel statique vertical nous ont conduit à émettre l'hypothèse d'une pathologie des canaux semi-circulaires verticaux non explorés en clinique. Nous décrivons une méthode d'exploration spécifique de ces canaux et reproductible en toute innocuité. Nous comparons les résultats à ceux d'un groupe de 15 témoins et à un groupe de 8 golfeurs professionnels pour évaluer l'influence de la pratique du golf sur le fonctionnement canalaire. Des tests statiques et cinétiques basés sur l'enregistrement du réflexe vestibulo-oculaire sont exposés et montrent des différences statistiquement significatives de fonctionnement des canaux semi-circulaires verticaux, et plus particulièrement des canaux postérieurs entre les sujets témoins et pathologiques.TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

Mental representation of space in vestibular patients with otolithic or rotatory vertigo.

International audienceIn previous studies, we had observed that the occurrence of geometric illusions was reduced when healthy observers were tilted relative to gravity or placed in microgravity. We hypothesized that the alteration of the gravitational (otolith) input was responsible for this change, presumably because of a connection between vestibular and visual-spatial cognitive functions. In this study, we repeated these experiments in vestibular patients who presented signs of otolith disorders. In agreement with the microgravity data, geometric illusions based on horizontal, vertical, and oblique lines were less frequent in patients with otolithic (nonrotatory) vertigo than in patients with rotatory vertigo and in healthy participants. Other visual illusions not based on perspective were not significantly different across all participant groups. We conclude that the impairment in the processing of gravitational input in the otolithic patients could be at the origin of a deformed mental representation of personal and extrapersonal space

Exploring the middle ear function in patients with a cluster of symptoms including tinnitus, hyperacusis, ear fullness and/or pain

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Role of Transferrin Receptor from a Neisseria meningitidis tbpB Isotype II Strain in Human Transferrin Binding and Virulence

Neisseria meningitidis acquires iron through the action of the transferrin (Tf) receptor, which is composed of the Tf-binding proteins A and B (TbpA and TbpB). Meningococci can be classified into isotype I and II strains depending on whether they harbor a type I or II form of TbpB. Both types of TbpB have been shown to differ in their genomic, biochemical, and antigenic properties. Here we present a comparative study of isogenic mutants deficient in either or both Tbps from the isotype I strain B16B6 and isotype II strain M982. We show that TbpA is essential in both strains for iron uptake and growth with iron-loaded human Tf as a sole iron source. No growth has also been observed for the TbpB(−) mutant of strain B16B6, as shown previously, whereas the growth of the analogous mutant in M982 was similar to that in the wild type. This indicates that TbpB in the latter strain plays a facilitating but not essential role in iron uptake, which has been observed previously in similar studies of other bacteria. These data are discussed in relation to the fact that isotype II strains represent more than 80% of serogroup B meningococcal strains. The contribution of both subunits in the bacterial virulence of strain M982 has been assessed in a murine model of bacteremia. Both the TbpB(−) TbpA(−) mutant and the TbpA(−) mutant are shown to be nonvirulent in mice, whereas the virulence of the TbpB(−) mutant is similar to that of the wild type

A contribution to the debate on tinnitus definition

International audienceTinnitus is generally defined as an auditory perception in the absence of environmental sound stimulation. However, this definition is quite incomplete as it omits an essential aspect, the patient's point of view. This point of view constitutes, first and foremost, a global and unified lived experience, which is not only sensory (localization, loudness, pitch and tone), but also cognitive (thoughts, attentiveness, behaviors) and emotional (discomfort, suffering). This experience can be lived in a very unpleasant way and consequently have a very negative impact on quality of life. This article proposes and justifies a new definition for tinnitus elaborated by a group of French clinicians and researchers, which is more in line with its phenomenology. It also provides a minimum knowledge base, including possibilities for clinical care, hoping to eradicate all misinformation, misconceptions and inappropriate attitudes or practices toward this condition. Here is the short version of our definition: Tinnitus is an auditory sensation without an external sound stimulation or meaning, which can be lived as an unpleasant experience, possibly impacting quality of life

La L-Thyroxine améliore la compensation vestibulaire dans un modèle de rat de vestibulopathie périphérique aiguë : Aspects cellulaires et comportementaux

International audienceUnilateral vestibular lesions induce a vestibular syndrome, which recovers over time due to vestibular compensation. The therapeutic effect of L-Thyroxine (L-T4) on vestibular compensation was investigated by behavioral testing and immunohistochemical analysis in a rat model of unilateral vestibular neurectomy (UVN). We demonstrated that a short-term L-T4 treatment reduced the vestibular syndrome and significantly promoted vestibular compensation. Thyroid hormone receptors (TRα and TRβ) and type II iodothyronine deiodinase (DIO2) were present in the vestibular nuclei (VN), supporting a local action of L-T4. We confirmed the T4-induced metabolic effects by demonstrating an increase in the number of cytochrome oxidase-labeled neurons in the VN three days after the lesion. L-T4 treatment modulated glial reaction by decreasing both microglia and oligodendrocytes in the deafferented VN three days after UVN and increased cell proliferation. Survival of newly generated cells in the deafferented vestibular nuclei was not affected, but microglial rather than neuronal differentiation was favored by L-T4 treatment