Factores relacionados con las lumbalgias de los instructores de paracaidismo en el túnel de viento / Factors related to low back pain of instructors for skydiving in the wind tunnel

El Túnel de viento (WT) es un dispositivo que simula, gracias a una corriente vertical de aire, de 300 km/hora, la caída libre previa a la apertura del paracaídas. Se utiliza principalmente para el aprendizaje del paracaidismo militar de apertura manual. En su interior, un instructor ayuda y asesora al alumno en sus movimientos y posiciones. Nuestro objetivo es establecer la frecuencia de episodios de dolor lumbar en estos instructores e identificar factores relacionados. Material y método: Estudio retrospectivo en el que participaron 19 de los 23 Instructores de vuelo en activo de España. Hemos registrado el número de episodios de lumbalgia, antecedentes profesionales, actividad paracaidista y de actividad física. Además, grabamos las sesiones de trabajo de los instructores identificando las posturas, gestos y acciones compatibles con la producción de lumbalgias mecánicas. Resultados: El 78,9% de los Instructores han padecido dolor lumbar en el último año. No hemos encontrado diferencias significativas en la presencia de lumbalgias entre los grupos establecidos a partir del IMC, el número de saltos durante toda su trayectoria, las horas/semana en el WT y los años como instructor. Tampoco hay relaciones con la práctica de otras actividades físicas. Mediante la grabación en video se ha observado que, en el interior del WT, los instructores adoptan todas las posturas, gestos y movimientos relacionados con la producción del dolor lumbar inespecífico. Todas esas actividades actúan provocando sobrecargas musculares y articulares. Son hiperlordosis, actitudes cifóticas dorsales y lumbares, traslado de cargas, mantenimiento de contracciones isométricas y movimientos de torsión. Conclusiones: Existe una alta incidencia de dolor lumbar en los instructores del WT. Las actividades realizadas por estos profesionales son de riesgo para la producción de lumbalgias mecánicas; por lo que es necesario diseñar programas de prevención de este problema (AU)

Wind tunnel (WT) is a device that simulates, thanks to a vertical stream of air, 300 km/h, the free fall prior to the opening of the parachute. It is mainly used for learning the military manual opening parachuting. Inside, an instructor helps and assists the student in their movements and positions. Our objective is to establish the frequency of episodes of low back pain in these instructors and identify related factors. Material and method: Retrospective study involving 19 of the 23 WT instructors active in Spain. We have recorded the number of episodes of low back pain, professional background, paratrooper-activity and physical activity. In addition, we recorded instructors work sessions to identify postures, gestures and actions compatible with the production of mechanical low back pain. Results: 78.9% of instructors have suffered from back pain in the past year. We have not found significant differences in the presence of low back pain among the groups established from BMI, the number of hops throughout his career, hours per week in the WT and years as an instructor. There is no relationship with the practice of other physical activities. Using the video recording has been observed that, in the interior of the WT, instructors adopt all postures, gestures, and movements related to the production of non-specific low-back pain. All these activities act causing overloads muscle and joints. They are hyperlordosis, dorsal and lumbar kyphotic attitudes, transportation of cargos, maintenance of isometric contractions and twisting movements. Conclusions: There is a high incidence of low back pain in the WT instructors. The activities carried out by these professionals are risk for the production of mechanical back pain; therefore, it is necessary to create protocols of prevention of this problem (AU)

Empirical validation of a rat in vitro organ slice model as a tool for in vivo clearance prediction.

Tissue slices have been shown to be a valuable tool to predict metabolism of novel drugs. However, besides the numerous advantages of their use for this purpose, some potential drawbacks also exist, including reported poor penetration of drugs into the inner cell layers of slices and loss of metabolic capacity during prolonged incubation, leading to underprediction of metabolic clearance. In the present study, we empirically identified (and quantified) sources of underprediction using rat tissue slices of lung, intestine, kidney, and liver and found that thin liver slices (+/-100 mum) metabolized model substrates (7-hydroxycoumarin, testosterone, warfarin, 7-ethoxycoumarin, midazolam, haloperidol, and quinidine) as rapidly as isolated hepatocytes. Furthermore, it was found that organ slices remain metabolically active for sufficient periods of incubation, enabling study of the kinetics of low clearance compounds. In addition, we determined the influence of albumin on the clearance prediction of six model substrates. For three of these substrates, the intrinsic clearance in the presence of albumin was approximately 3 times higher than that obtained from incubations without albumin, but corrected for unbound fraction. This resulted in a much more accurate prediction of in vivo whole body metabolic clearance for these compounds. Collectively, these results show that drawbacks of the use of slices for clearance prediction are largely surmountable. Provided that thin liver slices and physiological albumin concentration are used, whole body metabolic clearance is predicted with acceptable (2-fold) accuracy with organ slices. These results emphasize the applicability of organ slices in this field of research.