Fernando García Rodríguez

Cochlear microphonic audiometry: a new hearing test for objective diagnosis of deafness

Conclusions. Objective audiometric tests could constitute a valuable tool for detection of deafness. This could be especially useful in children (universal newborn hearing screening) and non-collaborative patients, who are especially difficult candidates for classic audiometry. The cochlear microphonic audiometry (CMA) technique offers the possibility of obtaining objective audiometric profiles, highly correlated with those obtained by pure tone audiometry (PTA). Therefore, CMA could be used as an alternative test to obtain the audiometric profile of these patients. Objective. The main purpose of the present study was to demonstrate that CMA provides objective audiometric profiles by avoiding active participation by the patient. Subjects and methods. CMA specific equipment, improved for non-invasive recording of cochlear microphonic potentials, was used. This tool plots the recordings obtained as the classic audiogram. Verification of the method was carried out in adult patients by comparing the PTA with the CMA audiometric profiles obtained for each patient. Results. Our findings showed that audiometric profiles obtained from CMA are highly correlated, without statistical differences, to those obtained with PTA. More than 81% of patients explored (91.67% at 250 Hz) exhibited differences below 10 dB(HL) between tests at all exploration frequencies, while a low number of cases showed differences over 20 dB(HL).

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.

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.

Cochlear nuclei neuroplasticity after auditory nerve and cochlea removal

Hearing loss clearly alters the function and connectivity in auditory pathways in the brain. The effects of an auditory receptor lesion on the auditory pathway might be linked to the absence of peripheral stimulation on the first level of the auditory pathway (cochlear nuclei, CN). Loss of stimulation affects the pathway connectivity, at least in the CN, inducing the reorganization of the neural circuits. This reorganization may reduce the efficiency of some deafness therapies, including cochlear implants. Cochlea removal has been shown to be a good model for analysing neuroplasticity in the CN. Three main periods of degeneration and regeneration were found after cochlea removal. During the first week after cochlea removal, early effects included auditory nerve fibre degeneration, and the progressive degeneration of nerve endings on CN neurons. Some CN neurons degenerate. From the second week after cochlea removal a very limited and diffuse expression of GAP-43, a protein linked to developing or regenerating axon growth cones, was found. Expression was observed in small nerve endings connecting cochlear nuclei neurons. One month after cochlea removal, CN were stabilized with a clear reduction of new neuron degeneration. At this time a very relevant expression of GAP-43 was found around remaining neurons, in particular in the ventral cochlear nuclei. Molecular aspects and control of neuroplasticity in cochlear nuclei still remains controversial, even though it is clear that trophic factors and many other substances (i.e. neurotransmitters) have been involved in neuroplasticity.

Formación de compentecias directivas

ResumenLa formacion de competencias directivas adolece, con escasas excepciones, de investigacion adecuada, realizada con el necesario rigor metodologico y orientada a objetivos relevantes. No es de extranar, por tanto, que la politica formativa, asi como los importantes recursos economicos que se invierten, no esten suficientemente justificados.Siguiendo una linea de trabajo desarrollada por este equipo investigador y realizada en condiciones adecuadamente controladas, no solo se ha comprobado y ratificado la eficacia de determinados procedimientos de formacion (los entrenamientos en habilidades sociales, aplicados a la formacion de competencias directivas), sino que ademas se ha confirmado la relevancia de estas tecnicas al afrontar situaciones de generalizacion, que exigen la aplicacion de las habilidades aprendidas a situaciones distintas, mas complejas y reales. En relacion a este ultimo tema se presentan los resultados y conclusiones obtenidos en la ultima investigacion realizada.

Arte y Crítica de Arte en el primer centenario de la Guerra de la Independencia

Analisis de la critica de arte en 1908, en torno a la inauguracion de monumentos conmemorativos, lapidas y exposiciones en Espana. Destacamos por su importancia: Exposicion Historica del Centenario en Madrid; Monumentos a los heroes del “2 de Mayo” en Madrid y Segovia; Monumento a los heroes de Tarragona de 1808 de Julio Antonio; Lapidas conmemorativas en Madrid de la “gesta”; Centenario de Espronceda y Maeztu; La “cuestion” Zuloaga, con unos sonetos de Eduardo Marquina; Monumento a los sitios de Zaragoza; Estatua a Castelar; Exposicion Patriotica de Zaragoza. Por todo ello calificamos este “Primer Centenario” como un intento de “paideia”, o educacion en los ideales de Espana.

Descripción y análisis de las críticas de arte publicadas por la Gaceta Literaria

Documentacion y analisis de las criticas de arte publicadas por La Gaceta Literaria, revista periodica quincenal, fundada y dirigida por Ernesto Gimenez Caballero, referente obligado de la “Generacion del ‘27”. La vertiente literaria ha sido ampliamente estudiada, pero su importancia, como defensora e impulsora de las vanguardias artisticas, y de la critica de arte, no habia sido abordada. La funcion de la critica, y de los criticos de arte, encuentra en sus paginas una formulacion mas acorde con los acontecimientos que se desarrollan en Europa y supone un claro posicionamiento de la minoria intelectual ante las nuevas corrientes emergentes fuera de Espana.