Anatomía radiológica de la base de cráneo y los nervios craneales parte 1: generalidades y base de cráneo / Skull base and cranial nerves radiologic anatomy part 1: basics and skull base

La anatomía de la base del cráneo es compleja. Numerosas estructuras neurovasculares vitales pasan a través de múltiples canales y formámenes de la base del cráneo. Con el avance de la tomografía computarizada (TC) y la resonancia magnética (RM) es posible la localización cada vez más precisa de lesiones y la evaluación de su relación con las estructuras neurovasculares adyacentes. El trayecto de los nervios craneales sigue un recorrido conocido y se transmiten a la cara y cuello a través de los forámenes de base de cráneo. La TC y la RM son complementarias entre sí y, a menudo, se usan en conjunto para demostrar la extensión completa de la enfermedad. La primera parte de esta revisión se centra en generalidades del estudio radiológico y anatomía de base de cráneo.

The skull base anatomy is complex. Many vital neurovascular structures course through the skull base canals and foramina. With the routine use of CT and MRI, the localization of lesions has become more precise as well as their relationship with adjacent neurovascular structures. There is a known anatomical course of the cranial nerves and their skull base s they course through the foramina towards the head and neck. CT and MRI are complimentary modalities and are often used together to map the full extent of disease. The first part of this review article series focus on the radiologic approach to disease and the skull base anatomy.

MRI findings of postherpetic abdominal wall pseudohernia: A case report.

Herpes zoster is caused by the reactivation of latent varicella-zoster virus from dorsal root ganglia. Although infrequent, simultaneous damage to the anterior horn cells or anterior nerve roots at the same level may result in motor neuropathy. When motor involvement is localized in the abdominal wall, a pseudohernia may be the clinical presentation. We report a case of abdominal wall post-herpetic pseudohernia, with clinical, ultrasound and MRI correlation. MRI demonstrated increased T2/STIR signal intensity in the abdominal wall muscles, suggesting acute denervation. To our knowledge, this is the first case report of postherpetic pseudohernia with acute denervation demonstrated on MRI.

[Usefulness of upper gastrointestinal series to detect leaks in the early postoperative period of bariatric surgery]. / Utilidad del estudio contrastado precoz del tracto digestivo superior después de cirugía bariátrica: ¿se justifica su uso rutinario?

BACKGROUND: Postoperative leaks are the most undesirable complication of bariatric surgery and upper gastrointestinal (GI) series are routinely ordered to rule them out. Despite the published literature recommending against its routine use, it is still being customarily used in Chile. AIM: To examine the usefulness of routine upper GI series using water-soluble iodinated contrast media for the detection of early postoperative leaks in patients undergoing bariatric surgery. MATERIAL AND METHODS: A cohort of 328 patients subjected to bariatric surgery was followed from October 2012 to October 2013. Most of them underwent sleeve gastrectomy. RESULTS: Upper GI series on the first postoperative day were ordered to 308 (94%) patients. Postoperative leaks were observed in two patients, with an incidence of 0.6%. The sensitivity for upper GI series detection of leak was 0% and the negative predictive value was 99%. CONCLUSIONS: Routine upper GI series after bariatric surgery is not useful for the diagnosis of postoperative leak, given the low incidence of this complication and the low sensitivity of the technique.

Utilidad del estudio contrastado precoz del tracto digestivo superior después de cirugía bariátrica: ¿se justifica su uso rutinario? / Usefulness of upper gastrointestinal series to detect leaks in the early postoperative period of bariatric surgery

Background: Postoperative leaks are the most undesirable complication of bariatric surgery and upper gastrointestinal (GI) series are routinely ordered to rule them out. Despite the published literature recommending against its routine use, it is still being customarily used in Chile. Aim: To examine the usefulness of routine upper GI series using water-soluble iodinated contrast media for the detection of early postoperative leaks in patients undergoing bariatric surgery. Material and Methods: A cohort of 328 patients subjected to bariatric surgery was followed from October 2012 to October 2013. Most of them underwent sleeve gastrectomy. Results: Upper GI series on the first postoperative day were ordered to 308 (94%) patients. Postoperative leaks were observed in two patients, with an incidence of 0.6%. The sensitivity for upper GI series detection of leak was 0% and the negative predictive value was 99%. Conclusions: Routine upper GI series after bariatric surgery is not useful for the diagnosis of postoperative leak, given the low incidence of this complication and the low sensitivity of the technique.

Tomografía computada de tórax en pediatría: indicaciones actuales / Pediatric chest computed tomography: current indications

The study of respiratory diseases is a common practice in pediatrics. Images play an important role and multidetector computed tomography (MDCT) is actually a significant pediatric modality. MDCT has advantages over conventional computed tomography . It enables radiation dose and intravenous contrast volume reduction, fast examinations, volumetric acquisitions during breath hold without artifacts, high quality images and multiplanar reformats. This article will review MDCT indications including lung nodules, chest masses, airway diseases, cervicothoracic, diaphragmatic and yuxtadiaphragmatic lesions, chest wall disease, vascular study, infections and congenital malformations. In conclusion, newer technologies in CT are safer and have extended indications in pediatrics.

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.

Modulation of (Na,K)-ATPase activity by membrane fatty acid composition: therapeutic implications in human hypertension.

Abstract 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.

Oxidative stress and pathophysiology of ischemic stroke: novel therapeutic opportunities.

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.

Antihypertensive role of polyphenols.

Hypertension is considered the most important risk factor in the development of cardiovascular disease. Considerable evidence suggests that oxidative stress, which results in an excessive generation of reactive oxygen species (ROS), plays a key role in the pathogenesis of hypertension. This phenomenon leads to endothelial dysfunction, an imbalance between endothelium-derived relaxing factors, such as nitric oxide (NO), and contracting factors, such as angiotensin-II and endothelin (ET)-1, favoring the latter. Vascular remodeling also takes place; both processes lead to hypertension establishment. Antioxidant therapies have been evaluated in order to decrease ROS production or increase their scavenging. In this line, polyphenols, widespread antioxidants in fruits, vegetables, and wine, have demonstrated their beneficial role in prevention and therapy of hypertension, by acting as free radical scavengers, metal chelators, and in enzyme modulation and expression. Polyphenols activate and enhance endothelial nitric oxide synthase (eNOS) expression by several signaling pathways, increase glutathione (GSH), and inhibit ROS-producing enzymes such as NADPH and xanthine oxidases. These pathways lead to improved endothelial function, subsequent normalization of vascular tone, and an overall antihypertensive effect. In practice, diets as Mediterranean and the "French paradox" phenomenon, the light and moderate red wine consumption, supplementation with polyphenols as resveratrol or quercetin, and also experimental and clinical trials applying the mentioned have coincided in the antihypertensive effect of polyphenols, either in prevention or in therapy. However, further trials are yet needed to fully assess the molecular mechanisms of action and the appearance of adverse reactions, if a more extensive recommendation of polyphenol introduction in diet wants to be made.