An original stereotactic radiosurgical approach coupling a) Talairach's stereotactic methodology, b) a specially devised mechanical system, and c) a linear accelerator is detailed. The authors present their preliminary results on 66 patients with nonsurgical intracranial arteriovenous malformations. The doses delivered for treatment varied from 20 to 70 Gy. Doses of no more than 40 Gy were used in 80% of patients. An angiographic study was performed when the computed tomographic scan controls showed relevant modifications of the lesion volume. Total obliteration was obtained in 27 of the 41 patients (65.8%) who were followed up for at least 24 months. The percentage of the cured patients is significantly higher when a) the entire malformation is included in the 75% isodose (96%) and b) the maximum diameter of the lesion is less than 12 mm (81%). Two patients died of rebleeding at 18 and 29 months after treatment.
The exact localization of subterranean cavities and the determination of their dimensions is very important for the planning of geotechnical and mining activities. It is a complicated geophysical task often at the limit of detection. Nevertheless geophysical investigation is the only alternative to a dense and expensive grid of boreholes. This report tests the usefulness of geoelectrical resistivity methods for cavity detection under some new aspects. The basis for evaluation was a theoretical analysis of different conventional and focussing measuring arrays and of special arrays for a geoelectrical research between two boreholes. The limit of detectability of a cylindrical cavity of defined cross‐section and depth was calculated for the different measuring arrays on the basis of computation of the apparent resistivity ρa. Furthermore, the influence of possible errors (current supply of the electrodes and the distance between the electrodes) is discussed for focussed systems. The second part of the article is directed at the behaviour of the apparent resistivity ρa, the disturbing potential δVd caused by the cavity and the normal potential δV0 of the measuring array all in relation to a homogeneous earth. Some new results are presented. In the last part of the article theoretical results are compared with some field measurements.
The anatomy Lesson of Dr. Nicolaes Tulp:The beginning of a medical utopia Rembrandt el pintor y los retratos R embrandt Harmenszoon van Rijn pintó este cuadro (Figura 1) a la temprana edad de 26 años. Nació el 15 de julio de 1606 en Leyden, una de las "cunas" de la educación médica. Fue a la universidad pero rápidamente se aburrió y solicitó a sus padres abandonarla para dirigirse a amsterdam y dedicarse al estudio de la pintura. En 1631 se casó con Saskia van Uylenburgh, que era la prima de uno de los vendedores de arte más exitosos de amsterdam. Este matrimonio le proporcionó importantes conexiones sociales para conseguir pedidos de retratos y pinturas de la alta sociedad holandesa. Es justamente su cuñado quien lo recomienda a Nicolaes Tulp, quien deseaba encargar un retrato grupal 1 .En el siglo XVII estos tipos de retrato eran muy populares en las Provincias Unidas o Países bajos, y se habían convertido en una verdadera institución social. El retrato grupal se transformó en el símbolo de una clase media que ascendía social y económicamente. además era socialmente bien visto aparecer en compañía de gente poderosa. Por este motivo, ¡muchas personas pagaban para aparecer en estos retratos! Para comprender esto hay que entender que salir en estos retratos era como salir en la actualidad (anacronismo mediante) en la tapa de una revista de novedades sobre el ambiente artístico 2 . Esto convertía a este tipo de cuadros en una difícil tarea para los pintores ya que debían cumplir con las pretensiones de todos los participantes que habían pagado y que querían estar ubicados en un lugar de privilegio. Contexto históricoamsterdam pertenecía a las Provincias Unidas cuya religión era el calvinismo y que venía de lograr su independencia de España luego de treinta años de guerra. Dicha independencia les permitió ganar el derecho a comerciar libremente. Las Provincias Unidas tuvieron un golpe de suerte,
Purposeto compare two populations of brachial plexus palsies, one neonatal (NBPP) and the other traumatic (NNBPP) who underwent different nerve transfers, using the Plasticity Grading Scale (PGS) for detecting differences in brain plasticity between both groups. MethodsTo be included, all patients had to have undergone a nerve transfer as the unique procedure to recover one lost function. The primary outcome was the PGS score. We also assessed patient compliance to rehabilitation using the Rehabilitation Quality Scale (RQS). Statistical analysis of all variables was performed. A p ≤ 0.050 set as criterion for statistical signi cance. Resultsa total of 153 NNBPP patients and 35 NBPP babies (with 38 nerve transfers) met the inclusion criteria.The mean age at surgery of the NBPP group was 9 months (SD 5.42, range 4 to 23 months. The mean age of NNBPP patients was 22 years (SD 12 years, range 3 to 69). They were operated around sixth months after the trauma. All transfers performed in NBPP patients had a maximum PGS score of 4. This was not the case for the NNBPP population, that reached a PGS score of 4 in approximately 20% of the cases. This difference was statistically signi cant (p < 0.001). The RQS was not signi cantly different between groups ConclusionWe found that babies with NBPP have a signi cantly greater capacity for plastic rewiring than adults with NNBPP. The brain in the very young patient can process the changes induced by the peripheral nerve transfer better than in adults.
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