ABSTRACT
Los cambios producidos durante el envejecimiento predisponen al adulto mayor a las caídas frecuentes, en el ambiente clínico el riesgo de caída es valorado mediante pruebas clínicas que muchas veces carecen de poder analítico, por lo cual es necesario describir cual de dichas pruebas puede tener mayor relación con parámetros biomecánicos analíticos con la finalidad de conferirle a dichas pruebas funcionales tales características. El objetivo de este trabajo fue describir la existencia de correlación entre los puntajes obtenidos en la prueba funcional "Timed up and go" (TUG) y momentos articulares del miembro inferior obtenidos durante la ejecución de la transferencia de sedente a bípedo (TSB) en sujetos adultos mayores con antecedentes de caídas frecuentes. Se obtuvo una muestra de 30 voluntarios, todos adultos mayores con antecedentes de caídas frecuentes, los que fueron evaluados con la prueba funcional de TUG. También se evaluó mediante un sistema de análisis de movimiento la TSB donde se registraron los parámetros biomecánicos necesarios para determinar los momentos articulares del miembro inferior. Existió una correlación significativa (r=-0,39; p=0,03) entre el puntaje obtenido en el TUG y el momento articular máximo de rodilla. Para la muestra evaluada, el tiempo de ejecución de la prueba "Timed up and go" fue indicador de la capacidad de generar momento articular por parte de los músculos flexo-extensores de rodilla en sujetos con antecedentes de caídas frecuentes.
The changes that take place during aging predispose the elder adult to frequent falls. In clinical practice fall risk is assessed by clinical tests that many times lack analytical power, therefore making it necessary to describe which of the clinical tests are related to the analytical biomechanical parameters in order to assign such characteristics to these functional tests. The objective of this work was to describe the existence of a correlation between the score of the functional test "Timed up and go" (TUG) and the joint moments of lower limb obtained during the execution of the sit to stand (STS) transfer in elderly subjects with a history of frequent falls. A sample of 30 volunteers was obtained; all were elders with a history of frequent falls. They were assessed with the functional test of TUG. Also assessed were the joint moments of the lower limb with motion analysis system. There is significant correlation (r=0.39; p=0.03) between the score obtained in the TUG and the maximum joint moment of the knee. For the sample assessed, the time of execution of the test "Timed up and go" was indicative of the capacity to generate a joint moment by the flexion-extensor muscles of the knee in subjects with a history of frequent falls.
Subject(s)
Humans , Male , Female , Aged , Lower Extremity/physiology , Exercise Test/methods , Biomechanical Phenomena , Accidental Falls , Standing Position , Joints/physiology , Movement/physiologyABSTRACT
Metal speciation analysis in MTs was carried out in two tropical fish species of Brazil, the freshwater fish pearl cichlid (Geophagus brasiliensis) and the marine fish white sea catfish (Netuma barba), that are presently used to monitor the effects of heavy metal pollution in aquatic ecosystems in Brazil. In order to obtain the MT fraction, liver cytosols from both fish species where subjected to size exclusion fractionation, monitoring on-line the metal signal (Cd, Cu and Zn) by ICP-MS while protein elution was followed by on-line UV detection. That MT fraction was then separated by anion-exchange (AE)-FPLC, whose optimal chromatographic conditions were optimized for the separation of the different hepatic MT isoforms existing in both fish species. Specific detection of separated metalloforms was carried out again by the hyphenation of the AE chromatographic system with the ICP-MS instrument. The analytical results showed that MTs of these fish species, unknown so far, exhibited unique characteristics in comparison with standard MTs and other fish liver MTs. In fact, MT isoforms of N. barba turned out to be very anionic, as indicated by their high retention in the Mono Q column and the strong ionic strength required to separate them. As for G. brasiliensis, cadmium was exclusively present in only one of the peaks of the MT isoforms showing a unique metal-binding behavior for MT in this fish species. The differences between the MTs among these species and the different association of metals in particular MT isoforms display the importance of the metal speciation analysis in these proteins prior to its use as bioindicators.
ABSTRACT
Cultured cerebellar granule neurons (CGC) increase survival in a medium containing 25 mM KCl (K25), and they die apoptotically when cultures are treated with staurosporine (St) or are transferred to a 5-mM KCl containing medium (K5). Apoptotic CGC show nuclear condensation and caspase-3 activation. Cell death induced by these conditions was partially prevented when cultures were maintained under alkaline conditions, which also induced a marked reduction of the caspase-3 activation. The acidification of the medium further increased cell death induced by both stimuli. Cultures transferred to K5 suffered an immediate intracellular alkalinization that remained constant during the time K5 was present. In contrast, St did not modify cytosolic pH at any of the evaluated times. On the other hand, DIDS, furosemide, and bumetanide prevented CGC death induced by K5 and St. Other drugs such as amiloride, EIPA, tamoxifen, NEM, or NPPB did not modify cell death induced by these conditions. Both DIDS and bumetanide markedly inhibited the processing and activation of caspase-3, and DIDS prevented the nuclear condensation induced by K5 and St. These findings suggest that pH is a condition that could contribute to the modulation of cell death induced by some stimuli and that other ions, such as potassium, could have a role in the initial phase of apoptotic death of CGC.