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Through a wide range of cellular and molecular events, the peripheral nervous system is endowed with great regenerative capacity, responding immediately to injuries that occur along the length of the nerve. The aim of this study was to histomorphometrically assess the degree of maturity of the nervous tissue and possible microscopic changes in newly formed nerve segments 60 days after experimental neurotmesis of the sciatic nerve in rats. Control Group (CG) and an Injury Group (IG) were used. IG underwent neurotmesis of the sciatic nerve of the right foot, with immediate surgical repair using the tubulization technique. 60 days following experimental surgery, animals from both groups had their sciatic nerves collected for histomorphometric analysis. Statistical analysis was performed, using the Student t-test for independent samples, expressed as mean ± standard deviation, with 5% significance. In the event of injury, peripheral nerve tissue is mobilized in an intrinsic self-healing process. 60 days following of nerve regeneration in neurotmesis injury, the peripheral nerve presents a segment joining the newly formed neural stump. The new stump has a number of regenerated axons compatible with an intact nerve, but which still show great immaturity in the axonal structural layers of the nerve. Mediante diversos procesos celulares y moleculares, el sistema nervioso periférico tiene una gran capacidad regenerativa, respondiendo inmediatamente a las lesiones ocurridas a lo largo de su extensión. El objetivo de este estudio fue evaluar histomorfométricamente el grado de madurez del tejido nervioso y los posibles cambios microscópicos en los segmentos nerviosos recién formados 60 días después de la neurotmesis experimental en el nervio ciático de ratas. Se utilizaron 9 ratas (Wistar) separadas en grupo control (GC, n= 4) y Grupo lesión (GL, n= 5). A los 60 días de vida, el grupo GL fue sometido a neurotmesis del nervio ciático de la miembro posterior derecho, con inmediata corección quirúrgica con la técnica de tubolización. Completados 60 días luego de la cirugía experimental, los animales de ambos grupos fueron anestesiados y sus nervios ciáticos seccionados para el análisis histomorfométrico. Se realizó un análisis estadístico utilizando la prueba t de Student para muestras independientes, expresado como media ± desviación estándar, con un 5% de significancia. A los 60 días de la lesión por neurotmesis, el nervio ciático del GL presentó alteraciones histomorfométricas significativas para las variables: número de vasa nevorum, densidad de fibras mielínicas, diámetro axonal y de fibras mielínicas, espesor de la vaina de mielina y razón G, con similitud solamente para los números absolutos de fibras mielínicas regeneradas. El nervio periférico durante su proceso regenerativo, pasa por grandes alteraciones estructurales, siguiendo una secuencia coordinada de acciones, que dependiendo de las condiciones del microambiente donde ocurre esta regeneración, podrá ser clave para el nivel de regenerecion nerviosa periférica.

INTRODUCTION: Surface electromyography has been used to assess the extrinsic laryngeal muscles during chewing and swallowing, but there have been few studies assessing these muscles during phonation. OBJECTIVE: To investigate the current state of knowledge regarding the use of surface electromyography for evaluation of the electrical activity of the extrinsic muscles of the larynx during phonation by means of an integrative review. METHOD: We searched for articles and other papers in the PubMed, Medline/Bireme, and Scielo databases that were published between 1980 and 2012, by using the following descriptors: surface electromyography and voice, surface electromyography and phonation, and surface electromyography and dysphonia. The articles were selectedon the basis ofinclusion and exclusion criteria. DATA SYNTHESIS: This was carried out with a cross critical matrix. We selected 27 papers,i.e., 24 articles and 3 theses. The studies differed methodologically with regards to sample size and investigation techniques, making it difficult to compare them, but showed differences in electrical activity between the studied groups (dysphonicsubjects, non-dysphonicsubjects, singers, and others). CONCLUSION: Electromyography has clinical applicability when technical precautions with respect to application and analysis are obeyed. However, it is necessary to adopt a universal system of assessment tasks and related measurement techniques to allow comparisons between studies.

PURPOSE: To non-invasively study the sensory nerve conduction of the caudal nerve of normal developing rats. METHODS: Twenty normal Wistar male rats served as subjects. Caudal nerve conduction studies were performed at 60 days from birth and weekly at end of six consecutive weeks. The caudal nerve was stimulated distally and nerve potentials were recorded proximally on the animal's tail using common "alligator" clips as surface electrodes. RESULTS: The amplitude and the conduction velocity of the caudal nerve sensory action potential increased linearly from 29±6 µV to 85±13 µV and from 34±3 m/s to 44±4 m/s, respectively, between the 8th and the 15th week of life. The equations of linear regressions were as followed: Amplitude (µV) = 8.1 × weeks - 34 (R² = 0.99) and NCV (m/s) = 1.2 × weeks + 25 (R² = 0.86). CONCLUSIONS: It was possible to study non-invasively the sensitive conduction of the caudal nerve of normal developing rats and describe reference values. The technique and data may be used as animal model in physiological and pathological studies. OBJETIVO: Estudar de forma não invasiva a condução nervosa sensitiva do nervo caudal em ratos normais em desenvolvimento. MÉTODOS: Vinte ratos machos Wistar foram utilizados. A conducão nervosa foi realizada a partir dos 60 dias, semanal durante seis semanas consecutivas. O nervo caudal foi estimulado distalmente, os potenciais foram registrados proximalmente na cauda do animal usando garras comum do tipo "jacaré" como eletrodos de superficie. RESULTADOS: A amplitude do potencial de ação de nervo sensitivo a velocidade de condução nervosa do nervo caudal cresceu linearmente de 29 ± 6 µV para 85 ± 13 µV e de 34 ± 3 m/s para 44 ± 4 m/s, respectivamente, entre a 8º e a 15º semana da vida do animal. As equações de regressão linear foram as seguintes: Amplitude (µV) = 8,1 × semanas - 34 (R² = 0,99) e velocidade de conducao nervosa (m/s) = 1,2 × semanas + 25 (R² = 0,86). CONCLUSÕES: Foi possível estudar de forma não invasiva a condução nervosa sensitiva do nervo caudal de ratos normais em desenvolvimento e descrever valores de referência. A técnica e os dados podem ser usados como modelo animal em estudos fisiológicos e patológicos.