INTRODUCTION: Cross-modal plasticity has been extensively studied in deaf adults with neuroimaging studies, yielding valuable results. A recent study in our laboratory with deaf-blind children found evidence of cross-modal plasticity, revealed in over-representation of median nerve somatosensory evoked potentials (SEP N20) in left hemisphere parietal, temporal and occipital regions. This finding led to asking whether SEP N20 changes are peculiar to deaf-blindness or are also present in sighted deaf children. OBJECTIVE: Assess cross-modal plasticity in deaf child cochlear implant candidates using neurophysiological techniques (visual evoked potentials and median nerve somatosensory evoked potentials). METHODS: Participants were 14 prelingually deaf children assessed in the Cuban Cochlear Implant Program. Flash visual-evoked potentials and SEP N20 were recorded at 19 scalp recording sites. Topographic maps were obtained and compared to those of control group children with normal hearing. Analysis took into account duration of hearing loss. RESULTS: Topographic maps of flash visual-evoked potentials did not show changes in deaf child cochlear implant candidates. However, SEP N20 from right median nerve stimulation did show changes from expansion of cortical activation into the left temporal region in deaf children aged >7 years, which was interpreted as neurophysiological evidence of cross-modal plasticity, not previously described for this technique and type of somatosensory stimulus. We interpret this finding as due in part to duration of deafness, particularly related to handedness, since expansion was selective for the left hemisphere in the children, who were all right-handed. CONCLUSIONS: Cortical over-representation of SEP N20 in the left temporal region is interpreted as evidence of cross-modal plasticity that occurs if the deaf child does not receive a cochlear implant early in life-before concluding the critical period of neural development- and relies on sign language for communication.

The great deal of evidence that has been collected for the last years in connection with the inflammatory nature of bronchial asthma have led us to make an obliged review of some important aspects of its physiopathology. Among these aspects, we consider it is very interesting the role played by the airway smooth muscle and nerves in the genesis and development of this disease. The protein kinase C (PKC) is involved in the maintained contraction of the airway smooth muscle in vitro and it may be of particular significance in patients with chronic asthma. The thickening of the airway smooth muscle is another characteristic of some patients with asthma and it may occur in the proximal parts and in the distal parts of the airways. Cough and chest "squeeze" are common symptoms in asthma and these symptoms are probably mediated by the activation of afferent nerves. Finally, the possible future questions that may define the research in the field of asthma physiopathology as regards the airway smooth muscle and pulmonary innervation are expressed

Gran cantidad de evidencia se ha recopilado en los últimos años con relación a la naturaleza inflamatoria del asma bronquial, lo que ha traído como consecuencia la revisión obligada de aspectos importantes de su fisiopatología, y entre estos aspectos consideramos de sumo interés el papel que juega el músculo liso bronquial y los nervios en la génesis y desarrollo de esta enfermedad. La proteína quinasa C (PKC) está involucrada en la contracción mantenida del músculo liso bronquial in vitro, y puede por tanto ser de particular importancia en pacientes con asma crónica. El incremento del engrosamiento del músculo liso de las vías aéreas es otra característica llamativa en algunos pacientes con asma, y puede tener lugar tanto en las partes proximales como distales de las vías aéreas. La tos y la "apretazón" en el pecho son síntomas comunes en el asma y probablemente estos síntomas están mediados por la activación de aferentes nerviosos. Finalmente se expresan las posibles interrogantes futuras que pudieran definir las investigaciones en el campo de la fisiopatología del asma en lo relacionado con el músculo liso bronquial y la inervación pulmonar

Intrinsic and allergic bronchial asthma has been defined as a persistent chronic inflammatory disorder based on increasing evidences. It has been proved that the clinical characteristics of bronchial asthma are connected with cellular parameters a well as with substances produced by bronchial inflammation processes. Therefors, took for evaluation and monitoring of asthmatic inflammation are being studied according to these variables that may allow to know the diagnosis and evolution of asthma at the same time. As eosinophils, T-limphocytes, mastocytes, macrophages, neutrophils, epithelial and structural cells, some proinflammatory mediators and proteins, particularly those from the eosinophil granules, have been involved in the pathogenesis of bronchial asthma, it has been anticipated that some of them may be used in the diagnosis of bronchial asthma or may serve as markers for monitoring subjacent bronchial inflammation. It was made a review of the present state of opinion regarding these mediators, which were included in this paper.

Se planteó que el asma bronquial intrínseca y alérgica ha sido definida como un trastorno inflamatorio crónico persistente, basados en un creciente cuerpo de evidencias. Se ha visto que las características clínicas del asma bronquial están relacionadas con parámetros celulares, así como con sustancias producidas por los procesos de inflamación bronquial, por lo tanto se están investigando medios de evaluación y monitoreo de la inflamación asmática según estas variables que pudieran permitir, al mismo tiempo, el diagnóstico y la evolución del asma. Desde que los eosinófilos, linfocitos T, mastocitos, macrófagos, neutrófilos, células epiteliales y estructurales, varios mediadores proinflamatorios y proteínas, particularmente las de los gránulos de los eosinófilos, han sido implicados en la patogénesis del asma bronquial, se ha anticipado que varios de ellos pudieran ser diagnósticos del asma bronquial o servir como marcadores para monitorear la inflamación bronquial subyacente. Se hizo una revisión del estado de opinión actual en relación con estos mediadores y se expusieron en el presente trabajo.