Stroke is the second leading cause of death, after ischemic heart disease, and accounts for 9% of deaths worldwide. According to the World Health Organization [WHO], 15 million people suffer stroke worldwide each year. Of these, more than 6 million die and another 5 million are permanently disabled. Reactive oxygen species [ROS] have been implicated in brain injury after ischemic stroke. There is evidence that a rapid increase in the production of ROS immediately after acute ischemic stroke rapidly overwhelm antioxidant defences, causing further tissue damage. These ROS can damage cellular macromolecules leading to autophagy, apoptosis, and necrosis. Moreover, the rapid restoration of blood flow increases the level of tissue oxygenation and accountsfor a second burst of ROS generation, which leads to reperfusion injury. Current measures to protect the brain against severe stroke damage are insufficient. Thus, it is critical to investigate antioxidant strategies that lead to the diminution of oxidative injury. The antioxidant vitamins C and E, the polyphenol resveratrol, the xanthine oxidase [XO] inhibitor allopurinol, and other antioxidant strategies have been reviewed in the setting of strokes. This review focuses on the mechanisms involved in ROS generation, the role of oxidative stress in the pathogenesis of ischemic stroke, and the novel therapeutic strategies to be tested to reduce the cerebral damage related to both ischemia and reperfusion.

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Oxidative stress (OS) plays a key role in the pathophysiology of essential hypertension and is associated with changes in the cell membrane fatty acid composition and fluidity. As (Na,K)-ATPase is modulated by the surrounding lipid microenvironment, lipid peroxidation could alter the interactions of this enzyme with the membrane components. Thus, modifications in the membrane fatty acid profile will translate into effects on (Na,K)-ATPase activity. Accordingly, a decrease in this enzyme activity has been reported in hypertensive patients. The aim of this study was to evaluate the relationship between membrane fluidity and fatty acid composition and (Na,K)-ATPase activity in erythrocytes of essential hypertensive patients supplemented with antioxidant vitamins C and E. A double-blind, randomized, placebo-controlled study was conducted in 120 men with essential hypertension assigned to receive vitamin C (1 g/day) +E (400 IU/day) or placebo for 8 weeks. Measurements included OS related parameters: GSH/GSSG ratio, F2-isoprostanes and antioxidant capacity of plasma, (Na,K)-ATPase activity and erythrocytes membrane fatty acid composition (PUFA, polyunsaturated fatty acids; SAFA, saturated fatty acids). Associations were assessed by Pearson correlation and the differences by Student t-test (p<0.05). Supplemented hypertensive patients showed higher activity of (Na,K)-ATPase and proportion of PUFA, and lower blood pressure, OS markers and proportion of SAFA, versus placebo. The activity of (Na,K)-ATPase correlated negatively with the proportion of SAFA, but positively with that of PUFA in both groups. Supplementation with vitamins C+E resulted in decreased OS and increased fluidity and PUFA proportion in the membrane, both of which positively modulate (Na,K)-ATPase activity, accounting for the blood pressure reduction.

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Usefulness of upper gastrointestinal series to detect leaks in the early postoperative period of bariatric surgery (Rev Med Chile 2016; 144: 451-455)

Introducción La anatomía de la base del cráneo es compleja. Numerosas estructuras neurovasculares vitales pasan a través de múltiples canales y forámenes ubicados en la base del cráneo. Es necesario tener una aproximación sistemática a la anatomía de la base de cráneo y conocer qué técnica de imagen se debe utilizar para poder optimizar su análisis y eva-luar los distintos procesos que pueden afectarla. La base del cráneo forma el piso de la cavidad craneal que separa el cerebro de las estructuras faciales y el cuello suprahioideo. La anatomía de la base del cráneo es compleja y no está directamente accesible para la evaluación clínica. La base del cráneo está compuesta por cinco huesos: frontal, etmoides, esfenoides, temporales y occipital. Se pueden identificar

El estudio de enfermedades que afectan el sistema respiratorio es una práctica cotidiana en pediatría. Las imágenes cumplen un rol muy importante y la tomografía computada multicorte (TCMC) tan alejada inicialmente de los niños tiene actualmente un rol muy importante. La TCMC ha aumentado significativamente el número de patologías posibles de estudiar ya que presenta ventajas en comparación con la tomografía convencional. Permite reducir la dosis de radiación y de volumen de contraste endovenoso, es un exámen extremadamente rápido, se consiguen adquisiciones volumétricas en apnea sin artefactos, imágenes de muy buena calidad y reconstrucciones multiplanares. Este artículo revisa las indicaciones de estudio con tomografía computada de nódulos pulmonares, masas torácicas, vía aérea, lesiones cervicotorácicas, diafragmáticas o yuxtadiafragmáticas, de la caja torácica, estudio vascular, infecciones y malformaciones congénitas. En conclusión, las nuevas tecnologías de tomografía computada han ampliado las indicaciones en pediatría, convirtiéndose en exámenes más seguros y altamente resolutivos.