Papers by julian rodriguez
Clinical Pharmacokinetics, 1991
The various components required for individualising clinical drug dosage regimens are reviewed, i... more The various components required for individualising clinical drug dosage regimens are reviewed, including a study of 3 types of fitting procedures, 2 types of gentamicin pharmacokinetic model and the utility of D-optimal times for obtaining serum gentamicin concentrations. The combination of the current Bayesian fitting procedure, the kslope pharmacokinetic model [in which the elimination rate constant (kel) can change from dose to dose with changing creatinine clearance] and the explicit measurement of the assay error pattern yielded predictions of future serum gentamicin concentrations which were (a) slightly better than those found using weighted nonlinear least squares; (b) somewhat better than those found with Bayesian fitting and a fixed-kel model; (c) better than those found using the traditional linear regression fitting procedure and a fixed kel model. D-Optimally timed pairs of concentrations also predicted future concentrations at least as well, and more cost effectively.
Acta Neuropathologica, 1994
We report a case of spinal cord neurocytoma in a 67-year-old man who had experienced a progressiv... more We report a case of spinal cord neurocytoma in a 67-year-old man who had experienced a progressive numbness of the left foot during the previous 4 years. Magnetic resonance imaging showed a well-defined intramedullary tumor located at the T10-Tll level. The pathological examination revealed histological characteristics described in neurocytomas. The tumor cells showed a uniform small nucleus and clear or slightly eosinophilic cytoplasm with frequent perinuclear halos, resembling the picture of oligodendroglioma. Some tumor cells exhibited mature ganglion cell appearance. Electron microscopy showed cells with microtubules and dense-core vesicles in their cytoplasm and cytoplasmic process. Immunohistochemically, the majority of tumor cells expressed synaptophysin and neuronspecific enolase. We conclude that this tumor is an exceptional case of neurocytoma located in the spinal cord, and consider that the term neurocytoma can be applied to tumors with neuronal differentiation intermediate between neuroblastoma and ganglioneuroma, even if arising in CNS outside of the intracranial ventricular system. Key words Neurocytoma 9 Spinal cord differentiation. It was first described by Hassoun et al. . Since then about 100 other cases have been reported ], very few of which were shown to be located in parts of the brain other than in the ventricular system . Only four cases have been described in the cervical cord . In this report we present a spinal cord tumor in a 67-year-old man, with the histological, immunohistochemical and ultrastructural characteristics of a central neurocytoma.
Microsurgery, 1995
An experimental model for local administration of neuronotrophic substances at the site of periph... more An experimental model for local administration of neuronotrophic substances at the site of peripheral nerve lesion is presented. The model consists of a subcutaneously located silicone reservoir and a connecting tube with its distal end fixed in the proximity of the severed and repaired nerve. The results of the preliminary tests of the model are presented. Sixty Sprague-Dawley rats were divided into two groups: control (saline-treated) (n=30) and NGF-treated (n=30). After axotomy of the sciatic nerve, an epineurial repair is performed. NGF or saline is injected daily into the subcutaneous reservoir during the first 3 weeks after axotomy and a single dose in the fourth week. The regenerated nerve observed in the NGF-treated group after four weeks of treatment presents a greater percentage of myelinated axons, thicker myeline sheaths, and more mature endoneurial layers. This experimental model provides a reliable and quantitative way to deliver neuronotrophic substances in site and at different administration rates. © 1995 Wiley-Liss, Inc.Se presenta un nuevo modelo experimental para la administración local de agentes neurotróficos en las lesiones del nervio periférico. El modelo consiste en un reservorio de silicona colocado subcutáneamente y un tubo conector cuyo extremio distal se fija en la proximidad del nervio seccionado y reparado. Se utilizaron 60 ratas de raza sprague-Dawley divididas en dos grupos: Control (tratadas con suero salino) (n=30) y NGF (tratadas con Factor de Crecimiento Nervioso) (n=30). Tras realizar la axotomía una sutura epineural. durante las 3 primeras semanas se administra diariamente en el reservorio subcutáneo NGF o suero salino, en la 4a semana se administra uns dosis única. el nervio regenerado observado en los animales del grupo tratado con NGF tras 4 semanas de tratamiento preseta un porcentage significativamente superior de axones mielinizados, vainas de mielina más gruesas y un endoneuro más maduro. Este modelo experimental proporciona un medio eficaz para administrar localmente sustancias neurotróficas a diferentes dosis y ritmos de administración. © 1995 Wiley-Liss, Inc.
La Acústica es la disciplina que se ocupa de estudiar el sonido en sus diversos aspectos. Se pued... more La Acústica es la disciplina que se ocupa de estudiar el sonido en sus diversos aspectos. Se puede dividir en una gran cantidad de subdisciplinas, algunas de las cuales se listan en la Tabla 1.1. Nosotros nos ocuparemos brevemente de sólo de las cuatro primeras de éstas, a saber: la acústica física, la psicoacústica, la acústica musical y la Tabla 1.1. Algunas subdisciplinas de la Acústica Rama Breve descripción Acústica física Análisis de los fenómenos sonoros mediante modelos físicos y matemáticos Psicoacústica Estudio de las sensaciones evocadas por los sonidos y sus diversos parámetros Acústica musical Estudio de los instrumentos musicales, las escalas, los acordes, la consonancia y la disonancia, etc. Acústica arquitectónica Estudio de la acústica de salas y su influencia sobre la escucha de la palabra y la música Bioacústica Estudio del efecto de los sonidos sobre los seres vivientes, y de los sonidos producidos por éstos Acústica fisiológica Estudio del funcionamiento del aparato auditivo, desde la oreja hasta la corteza cerebral Acústica ultrasónica Estudio del ultrasonido, es decir el sonido inaudible de alta frecuencia, y sus aplicaciones Acústica subacuática Estudio del comportamiento del sonido en el agua, y sus aplicaciones Macroacústica Estudio de los sonidos extremadamente intensos, como el de las explosiones, turborreactores, etc. Acústica estructural Estudio del sonido que se propaga por las estructuras en forma de vibraciones Acústica fonética Análisis de las características acústicas del habla y sus aplicaciones Mediciones acústicas Técnicas de medición de diversos parámetros acústicos como frecuencia, intensidad, espectro, etc.
Uploads
Papers by julian rodriguez