Infecciones del sistema nervioso: nuevas herramientas diagnósticas / Central nervous system infections: new diagnostic tools

Las infecciones del sistema nervioso constituyen un problema emergente de salud. Su pronóstico es desfavorable si el tratamiento no es el adecuado, por lo que, para comenzar rápidamente con una apropiada estrategia terapéutica, es necesario establecer el diagnóstico de forma precisa. Sin embargo, esto representa un verdadero desafío. El rendimiento relativo de los métodos de diagnóstico por imágenes es bien conocido: mientras la tomografía computada (TC) permite una valoración inicial general de la estructura, la resonancia magnética (RM) es el procedimiento de elección, a pesar de su baja especificidad. No obstante, en los últimos anos ˜ esto se ha visto sustancialmente modificado por la introducción en la práctica diaria de nuevas modalidades de resonancia que permiten un análisis estructural y funcional más preciso, brindando, además, información fundamental para el diagnóstico. Así, gracias a las técnicas de difusión, perfusión y espectroscopia (entre otras), se puede realizar un análisis más profundo que, junto con la clínica y los estudios de laboratorio, mejora significativamente la sensibilidad y especificidad del método en este complejo grupo de pacientes. Revisamos las formas de presentación de las patologías infecciosas más frecuentes del sistema nervioso, destacando los aportes de las técnicas funcionales o de las secuencias convencionales modificadas.

Central nervous system infections are an emerging health problem with poor prognosis if treatment is not adequate. Thus, establishing a correct diagnosis is necessary to quickly start the appropriate treatment. This is a real challenge for the radiologist, as it frequently requires a multidisciplinary approach. The relatively low performance of diagnostic imaging is well known. While computed tomography (CT) is limited only to an initial structural assessment, with magnetic resonance imaging (MRI) being the method of choice, although it has a low specificity. However, this has been substantially modified in recent years with the introduction into daily practice of new magnetic resonance sequences that allow precise structural and functional analysis, and provide essential additional information for final diagnosis. Now, due to the techniques of diffusion, perfusion, and spectroscopy, among others, a more detailed analysis can be made in conjunction with clinical and laboratory studies that signifi- cantly improve the sensitivity and specificity of MRI in this complex patient group. The patterns of the most common infectious diseases of the nervous system are reviewed here, highlighting the contributions of functional sequences in these complex patients.

[Topographic anatomy of the asterion]. / Anatomía topográfica del asterion

BACKGROUND: In the surgical approaches to the posterior fossa, the accurate location of the transverse-sigmoid sinus (TS-SS) complex is of great importance. The asterion is a referral landmark to the transverse sinus location. METHOD: Twenty-five skulls of adult cadavers were studied. We seek for the relationships of the asterion with: TS location, mastoid emissary vein, suprametal crest and inion. RESULTS: The asterion was found in 49 cases. In the great majority of cases (87.8%) the asterion was over the TS (72.2% over the sinus proper, 27.8% over the TS-SS transition). The mastoid emissary vein was present in 46 cases, and in 36% we found two veins. DISCUSSION AND CONCLUSIONS: The burr hole for posterolateral approaches to the posterior fossa must be located below and behind the asterion.

Anatomía topográfica del asterion / Topographyc anatomy of the asterion

Introducción. Las referencias anatómicas que permitenubicar los senos venosos durante los abordajes de fosa posterior, son de utilidad para el neurocirujano. El asterion es usado como referencia para localizar cl seno transverso (ST). Material y método. Se utilizaron 50 hemicráneos de cadáveres adultos. Se estudió la relación del asterion con el ST, la vena emisaria mastoidea (VEM), la cresta suprameatal y el inion. Resultados. Se identificó el asterion en 49 casos. En el 87.8% de las piezas, se situó a la altura del seno transverso. El 72.2% se ubicó sobre el propio seno y el 27.8% sobre su codo. Si se traza una línea desde la cresta suprameatal al inion, el asterion se ubica por debajo de esta línea en el 88% de los casos. El foramen de la VEM se identificó en 46 oportunidades,en el 36% fue doble. Discusión y conclusiones. Según nuestros datos y los de otros autores, el orificio de trépano debe situarse por debajo y algo detrás del asterion para evitar la lesión del seno transverso

Background. In the surgical approaches to the posteriorfossa, the accurate location of the transverse-sigmoidsinus (TS-SS) complex is of great importance. The asterion is a referal landmark to the transverse sinus location. Method. Twenty-Iive skulls of adult cadavers were studied. We seek for the relationships of the asterion with: TS location, mastoid emissary vein, suprameatal crest and inion. Results. The asterion was found in 49 cases. In the great majority of cases (87.8%) the asterion was over the TS (72.2% over the sinus proper, 27.8% over the TS-SS transition). The mastoid emissary vein was present in 46 cases, and in 36% we found two veins. Discussion and conclusions. The burr hole for posterolateral approaches to the posterior fossa must be located below and behind the asterion

Variaciones del sector anterior del polígono de Willis. Correlación anatomo-angiográfica y su implicancia en la cirugía de aneurismas intracraneanos (Arterias, ácigos cerebral anterior, mediana del cuerpo calloso y cerebral media accesoria) / Variants of the anterior circle of Willis, Anatomic and angiografic correlation and its implications in the surgery of itnracranial aneurysms

Es universalmente aceptado que el polígono de Willis presenta variantes en su anatomía habitual, hasta en el 60% de los casos. Algunas de éstas se asocian a malformaciones vasculares, como los aneurismas. El conocimiento de estas variantes anatómicas es de fundamental importancia con vistas al acto quirúrgico, con el fin de preservar arterias en topografía poco habituales y cuya lesión puede determinar secuelas invalidantes. Los autores, en revisión anatómica de 192 hemisferios cerebrales, encuentran tres variantes del sector anterior del Polígono de Willis: arteria ácigos cerebral anterior, arteria mediana del cuerpo calloso y arteria cerebral media accesoria. Se realiza la descripción anatómica de los hallazgos, la correlación con la angiografía y finalmente cómo influyeron estos cambios en el acto quirúrgico de aneurismas de las regiones implicadas (AU)

It is worlwide accepted that in almost 60% of cases, anatomical variants in the Circle of Willis can be found. Some of them are associated with vascular malfor¬mations such as aneurysms. The knowledge of these anatomical variants is of vital importance when facing surgery, being the aims to preserve arteries in unusual localisations, which when injured can determine invali¬dating sequelae. The authors have reviewed 192 cerebral hemis¬pheres, finding three variants in the anterior Circle of Willis: Azigos anterior cerebral artery; Median artery of the corpus callosum and accesory middle cerebral artery. The authors make an anatomical description of the findings, their angiographical correlation, and describe the influence of these changes during surgery of aneurysms in the involved regions (AU)

[Variants of the anterior circle of Willis. Anatomic and angiografic correlation and its implications in the surgery of intracranial aneurysms. (Acigos anterior cerebral artery, median artery of the corpus callosum and accessory middle cerebral artery)]. / Variaciones del sector anterior del polígono de Willis. Correlación anatomo-angiográfica y su implicancia en la cirugía de aneurismas intracraneanos. (Arterias: ácigos cerebral anterior, mediana del cuerpo calloso y cerebral media accesoria.

It is worlwide accepted that in almost 60% of cases, anatomical variants in the Circle of Willis can be found. Some of them are associated with vascular malformations such as aneurysms. The knowledge of these anatomical variants is of vital importance when facing surgery, being the aims to preserve arteries in unusual localisations, which when injured can determine invalidating sequelae. The authors have reviewed 192 cerebral hemispheres, finding three variants in the anterior Circle of Willis: Azigos anterior cerebral artery; Median artery of the corpus callosum and accessory middle cerebral artery. The authors make an anatomical description of the findings, their angiographical correlation, and describe the influence of these changes during surgery of aneurysms in the involved regions.

Self-assembling of proteins and enzymes at nanoscale for biodevice applications.

Different nanotechnological strategies have been selected to implement biomolecular devices following a bottom-up or top-down approach depending on the biomolecule and on its functionality. Biomolecules have particular functionality and self-assembling capabilities that can be exploited for the implementation of both bioelectronic devices and multipurpose engineered biosurfaces. Surface preparation with supramolecular methods and microcontact printing have been developed and optimised to realise suitable functionalised surfaces. These surfaces can be used to link metalloproteins and enzymes for the implementation of nanobioelectronic devices and planar biosensors or to bind cells in order to promote their growth along predefined tracks and grooves. Some possible applications of these biosurfaces are shown and discussed. Results are presented for the realisation of a biomolecular nanodevice working in air based on the metalloprotein azurin immobilised in the solid state, the formation and characterisation of functional glutamate Dehydrogenase monolayers for nanobiosensing applications, the results of soft lithography processes on azurin for biosensor implementation, and the development of physiological self-assembled patterns of laminin-1 for cell culture applications and hybrid devices.

The toxic responses induced by okadaic acid involve processing of multiple caspase isoforms.

The recognized role of caspases as executioners of apoptosis, led us to investigate their involvement in death responses induced by okadaic acid (OA) in HeLa S(3) and MCF-7 cells. A one-day treatment with OA induced accumulation of the 85kDa poly(ADP-ribose) polymerase (PARP) fragment in cell lysates but the response was prevented if cells were treated with OA in the presence of the caspase inhibitors Z-VAD-FMK and Z-DEVD-FMK. The HeLa S(3) and MCF-7 cells were found to contain measurable levels of the intact caspase-2, -7, -8 and -9 zymogens, whereas caspase-3 was found only in HeLa cells. After one day of OA treatment, pro-caspase-2, -3, -7 and -9 isoforms were found processed in HeLa cells, whereas only pro-caspase-2 was processed in MCF-7 cells. Pro-caspase-8, in turn, was mostly unprocessed in both cell lines. The possible interference of caspase inhibitors on cell death was also evaluated, and we found that both Z-VAD-FMK and Z-DEVD-FMK could contribute different extents of protection of MCF-7 and HeLa cells from toxic effects caused by OA. We concluded that OA triggers multiple pathways of caspase processing, contributing to death responses triggered by OA in HeLa S(3) and MCF-7 cells.