Maduración postnatal del receptor acústico de la rata

Fac. de MedicinaTRUEProQuestpu

Maduración postnatal del receptor acústico de la rata

Fac. de MedicinaTRUEProQuestpu

Maturation des elements sensorinerveux de la cochlee

SIGLEINIST T 77334 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Telemedicine applied to urgent healthcare: methodological and practical aspects.

Actualmente la Telemedicina (TM) es una realidad en el trabajo diario de muchas especialidades médicas. El desarrollo y el aumento de la disponibilidad de las nuevas tecnologías de información y comunicación, junto con la flexibilidad de conectividad de los equipamientos médicos hace posible la asistencia médica de pacientes que tienen dificultades de acceso a un centro hospitalario. Una de las aplicaciones más importantes de la TM es la asistencia en Medicina de Urgencias. La experiencia acumulada por distintas especialidades médicas ha permitido un gran aumento de las posibilidades de atención urgente en las que la TM puede ser aplicable tanto en el entorno hospitalario como lejos del hospital. Además, las características propias de la atención sanitaria de urgencia, como son la necesidad de rapidez y de fiabilidad en el diagnóstico, hace que cada vez se requieran más y mejores equipamientos y soluciones. El incremento de la comunicación entre especialistas de urgencias con otras especialidades puede permitir mejores diagnósticos con la consiguiente disminución de la morbi-mortalidad en los pacientes que se atienden de urgencia. El presente trabajo revisa la aplicabilidad de la TM en urgencias, así como la tecnología implicada en ello.Depto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEpu

Immunocytochemical detection of synaptophysin in C57BL/6 mice cochlea during aging process

Aged mammals frequently exhibit a bilateral, progressive, and symmetric deafness related to the degeneration of auditory receptor. However, little is still known about aging effects on synapses in this receptor. Synaptophysin (Syp) is a 38 kDa Ca2+ binding glycoprotein widely found in presynaptic membrane and vesicles. The Syp has been found in presynaptic buttons of efferent auditory fibers, within the developing and adult auditory receptor. The detection of Syp in aged cochleae could provide relevant information about synaptic changes and receptor degeneration process observed in old animals. This paper focuses on aging linked changes related to the presence of Syp in cochleae of C57BL/6J mice (from 1 to 24 months old). Results showed that during the first months of age, no significant changes were observed in the Syp distribution under the basal pole of inner (IHCs) neither the outer (OHCs) hair cells. At six months of age, a significant decrease of Syp immunocytochemical detection appeared in fibers under the most external row of OHCs, but restricted to the cochlear basal coil. Only a very scarce reduction of Syp was noted under the IHC and the other OHC rows, also at the basal coil. From mice 9 months old on, a progressive decrease of the presence of Syp was found under IHC and all OHC rows starting at the basal coil and reaching the apical coil in the oldest mice. All these data could indicate that the cochlea aging process early affects to presynaptic membrane proteins of efferent endings fibers. This early alteration of cochleae efferent synapses could be involved in the whole degeneration of the Corti's organ.Universidad Complutense de MadridDepto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEpu

In vitro long-term development of cultured inner ear stem cells of newborn rat

The adult mammalian auditory receptor lacks any ability to repair and/or regenerate after injury. However, the late developing cochlea still contains some stem-cell-like elements that might be used to regenerate damaged neurons and/or cells of the organ of Corti. Before their use in any application, stem cell numbers need to be amplified because they are usually rare in late developing and adult tissues. The numerous re-explant cultures required for the progressive amplification process can result in a spontaneous differentiation process. This aspect has been implicated in the tumorigenicity of stem cells when transplanted into a tissue. The aim of this study has been to determine whether cochlear stem cells can proliferate and differentiate spontaneously in long-term cultures without the addition of any factor that might influence these processes. Cochlear stem cells, which express nestin protein, were cultured in monolayers and fed with DMEM containing 5% FBS. They quickly organized themselves into typical spheres exhibiting a high proliferation rate, self-renewal property, and differentiation ability. Secondary cultures of these stem cell spheres spontaneously differentiated into neuroectodermal-like cells. The expression of nestin, glial-fibrillary-acidic protein, vimentin, and neurofilaments was evaluated to identify early differentiation. Nestin expression appeared in primary and secondary cultures. Other markers were also identified in differentiating cells. Further research might demonstrate the spontaneous differentiation of cochlear stem cells and their teratogenic probability when they are used for transplantation.Depto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEpu

Electrophysiological monitoring of hearing function during cochlear perilymphatic perfusions

Conclusion: The cochlear perilymphatic perfusion produces, by itself, significant effects in the cochlear physiology that could be associated with the surgical procedure. These effects need to be well characterized to allow a reliable quantification of the effects of the experimental agent being tested. Objectives: The study focused on the accurate description of the electrophysiological effects on the cochlear potential recordings of perilymphatic perfusions. Methods: Two successive cochlear perilymphatic perfusions were carried out. The first used artificial perilymph. The second used artificial perilymph alone or a kainic acid (KA) solution in artificial perilymph. The compound action potential of the auditory nerve (CAP-AN) was recorded: (1) before the first perfusion, (2) after the first perfusion and (3) after the second perfusion, and compared between groups. Results: The first intracochlear perfusion with artificial perilymph produced significant effects in the CAP-AN that could be related to the surgical procedure. These effects were analysed separately from the effects produced by the KA. In particular, the KA administered intracochlearly produced a significant increase in the latency and a decrease in the amplitude of the CAP-AN N1 wave compared with the controls that were perfused twice with artificial perilymph.Universidad Complutense de MadridDepto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEpu

Cellular and molecular bases of neuroplasticity: brainstem effects after cochlear damage

After a cochlear lesion or auditory nerve damage, afferent connections from auditory ganglia can be highly altered. This results in a clear reduction of auditory input and an alteration of connectivity of terminals on cochlear nuclei neurons. Such a process could stimulate the reorganization of the neural circuits and neuroplasticity. Cochlea removal has been demonstrated to be a good model in which to analyse brainstem neuroplasticity, particularly with regard to the cochlear nuclei. After cochlea removal three main periods of degeneration and regeneration were observed. Early effects, during the first week post lesion, involved acute degeneration with nerve ending oedema and degeneration. During the second and, probably, the third post lesion weeks, degeneration was still present, even though a limited and diffuse expression of GAP-43 started. Around 1 month post lesion, degeneration at the cochlear nuclei progressively disappeared and a relevant GAP-43 expression was found. We conclude that neuroplasticity leads neurons to modify their activity and/or their synaptic tree as a consequence of animal adaptation to learning and memory. For the human being neuroplasticity is involved in language learning and comprehension, particularly the acquisition of a second language. Neuroplasticity is important for therapeutic strategies, such as hearing aids and cochlear implants.Universidad Complutense de MadridDepto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEpu