RESUMO
The expression of T-type voltage-dependent Ca2+ channels (Cav3) has been previously observed in breast cancer, but their expression and subcellular localization were not evaluated in pre-neoplastic lesions. Therefore, this work aimed to evaluate protein expression and subcellular localization of T-type channel isoforms in human breast tissue samples. Protein expressions of CaV3.1, CaV3.2, and CaV3.3 were evaluated by immunohistochemistry in breast without alteration, in proliferative non-neoplastic lesions, and in neoplastic ductal epithelial lesions of the human breast. CaV3.1, CaV3.2, and CaV3.3 nuclear expressions were decreased in advanced stages of neoplastic transformation, whereas CaV3.1 and CaV3.2 cytoplasmic expression increased. Also, the decrease in nuclear expression was correlated with an increase in cytoplasmic expression for CaV3.1 isoform. The change in CaV3 protein expression and subcellular localization are consistent with the neoplastic transformation stages of mammary epithelial cells, evident in early neoplastic lesions, such as ductal carcinomas in situ. These results suggest a possible involvement of CaV3 in the carcinogenic processes and could be considered as a potential pharmacological target in new therapies for breast cancer treatment.
RESUMO
Objetivo. Comparar la influencia de las velocidades de contracción lenta y rápida en el volumen total de carga levantada en una sesión de entrenamiento de resistencia con ejercicios de pesos libres para miembros superiores, y analizar el tiempo de recuperación de la fuerza máxima del músculo después del ejercicio en la resistencia de hombres entrenados. Métodos. Dieciséis hombres jóvenes que tenían experiencia en el entrenamiento de la resistencia fueron divididos aleatoriamente en dos grupos: la velocidad de contracción rápida (FCV - n = 8) y la velocidad de contracción lenta (SCV - n = 8). Ambos grupos realizaron el ejercicio de press de banca y press banca inclinado (pesos libres) con 4 series de 12 repeticiones máximo; y un intervalo de 50 segundos de descanso entre cada serie y 2 minutos entre los ejercicios. La velocidad de contracción fue de 6 segundos para el grupo SCV y 1,5 segundos para el grupo de FCV. El volumen total de carga fue anotado durante la sesión de ejercicio; y una repetición máxima (1RM) fue evaluada antes (basal) y durante 96 horas después del ejercicio para medir la función neuromuscular. Resultados. Los resultados demostraron que el grupo de FCV proporcionó un mayor (p < 0,05) volumen de carga levantada durante la sesión de ejercicio, y tuvo una disminución significativa (p < 0,05) en el rendimiento neuromuscular después del ejercicio, en comparación con el grupo SCV. Conclusión. Estos datos sugieren que además de la velocidad de contracción, el volumen total de carga elevada determina la disminución de la función neuromuscular después del ejercicio en la resistencia de hombres entrenados(AU)
Objective. To compare the influence of slow and fast contraction velocities in the total volume of load lifted in a resistance training bout with free weights exercises for upper limbs, and analyze the recovery time of the maximum muscle strength post-exercise in resistance-trained men. Methods. Sixteen young men, who were experienced in resistance training were randomly divided into two groups: fast contraction velocity (FCV - n = 8) and slow contraction velocity (SCV - n = 8). Both groups performed bench press and incline bench press exercises (free weights) with 4 sets of 12 repetitions maximum. There was a 50 seconds rest interval between each set, and 2 minutes interval between the exercises. The contraction velocity was 6 seconds for the SCV group and 1.5 seconds for the FCV group. The total volume of load was recorded during the exercise bout, and the one repetition maximum (1RM) was evaluated before (baseline) and for 96 hours after exercise to measure the neuromuscular function. Results. The results demonstrated that the FCV group provide a higher (p < 0.05) volume of load lifted during the exercise bout, and had a significant decline (p < 0.05) in the neuromuscular performance post-exercise, when compared to the SCV group. Conclusion. These data suggest that besides the contraction velocity, the total volume of load lifted determines the decline of neuromuscular function post-exercise in resistance-trained men(AU)
