737 research outputs found

    Estudio experimental de la Microangiografía del Tronco Ciático de la rata en situaciones de normalidad: compresión y descompresión

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    Se hace un estudio en 20 ratas sometidas a compresión del nervio ciático según variante de la técnica de WEISL y OSBORNE, y compresión-descompresión a tiempos variables y se estudia la microcirculación del mismo en estas situaciones, comparativamente con el nervio normal. Entre los cambios del patrón vascular en la compresión nerviosa, resalta la intensa vascularización de las zonas inmediatamente proximales y distales al a compresión, contrastando con la escasez de vasos en el área selectivamente comprimida. Después de la descompresión se apreció una recuperación paulatina del patrón vascular, sin que se llegase a alcanzar una cuantificación de vasos similar a la de las zonas adyacentes.A study in 20 rats with nerve sciatic compression (WEISL and OSBORNE method), and compression descompresión in diferent time s wa s made. The authors studied the sciatic nerve microcirculation in this situations in front of the normal nerve. They saw an intensive vascularization immediately after and before the place of the compression, and a vessels scarcity in the compression area. After the descompresion it saw a normal and slowly recuperation of the vascular role, but never so many vessels as in the proximal zones

    Regeneración del Tronco Nervioso Periférico: estudio experimental

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    Los autores realizan un estudio en 24 ratas sometidas a axonectomía parcial subepineural o axonectomía y vaciamiento troncular, con objeto de valorar el comportamiento de los distintos elementos celulares del nervio durante la regeneración nerviosa. Durante el tiempo del experimento las células perineurales se conservan alrededor de un espacio virtual, lo que se interpreta como que intervienen como aislante, aún en condiciones de ausencia de fibras nerviosas, impidiendo la entrada de estructuras vasculares neoformadas y la cicatrización intraperineural. Por todo ello se postula que el papel de "guía" para el crecimiento de los axones regenerativos, atribuido fundamentalmente a las células de SCHWANN, debe ser revisado, en el sentido de dar un mayor protagonismo a las células perineurales.A study of 24 rats with partial subepineural axonectomy or axonectomy with trunckular casting was made in order to value the role of the diferent cellular elements of the nerve during his regeneration. In the experiment the perineural cells persist around a virtual space. This mean that the cells works like an insulate, also in absence of nerve fibres, impeding the neoformed vessels entrance and the perineural cicatrizacion. The role of the SCHWANN cells is cuestioned in front of the perineural cells importance

    Sustitución del Menisco por Pericondrio Auricular: estudio experimental

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    Los autores realizan un estudio experimental en la rat a sustituyendo el menisco por pericondrio auricular, unas veces en forma plana y otras plegado en U. Ello provoca una respuesta reparativa con formación de verdadero cartílago. Cuando el pericondrio se injerta plegado en U de forma que la superficie de ruptura de las cápsulas condrocitarias se enfrenten entre sí, se asiste a la neoformación de dos clases de cartílago, una que aparece en la capa más interna del pericondrio y otro en las zonas de repliegue de éste último. Se discute el posible origen de estos dos tipos de neocartílago.The authors carry out an experimental study to evaluat e the replacement of the medial meniscus in the rat kne e by auricular perichondrial grafts (simple or plicated).This bring about a reparative replay with formation of cartilage tissue. When the perichondrial graft was used at the plicated form, it could keep out two kinds of neoformated cartilage; the first appeared in the most internal stratum of the perichondrium; the second type was found in the withdrawal zone of it. The possible origen of the neocartilage form is discussed

    Características Histológicas del Menisco de la rodilla durante el Desarrollo Intrauterino de la rata

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    Con el objetivo de profundizar en el conocimiento del desarrollo embriológico del esbozo meniscal de la rodilla, los autores realizan un estudio en embriones de rata de 16 y 20 días de gestación. Se comprueba como este esbozo meniscal, que en su inicio esta formado por una masa de células mesenquinales, adopta una configuración triangular al corte frontal, situada entre las dos superficies articulares. Posteriormente su vértice experimenta diferenciación cartilaginosa (futuro menisco), mientras que la región periférica sigue siendo altamente vascular y se continúa con tejido conjuntivo fibroso (zona parameniscal).An study in embryos of rat betwen 16-20 days of pregnancy was made to show the meniscus development. The meniscus sketch in the first time was made by mesenchyme cells, later takes a triangular configution. An at past his vertex became to be a cartilage (future meniscus), while the peripheral placer is highly vascular and is followed by a fibrous connective tissue (parameniscal zone)

    Estudio histológico de la respuesta reparativa tras extirpación del menisco y parcial del Paramenisco: estudio experimental

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    Los autores efectúan un estudio en la rat a utilizando un modelo experimental de meniscectomía completa y extirpación parcial del paramenisco, comprobándose como se origina un proceso de regeneración que conduce a la formación de una nueva estructura, de aspecto meniscal, de menor tamaño que el primitivo menisco y formado por tejido fibroso con focos condroides.An experimental study was made in the rat with total meniscus extirpation. This study show a regeneration process that take us to a new structure formation like meniscus, with fibrous tissue formation with condroid points

    Estudio experimental de la Neuropatía por Compresión en el Nervio Ciático de la Rata: después de la Descompresión Quirúrgica

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    Se hace un estudio en 40 ratas en las que se practica compresión del nervio ciático, según una variante de la técnica de WEISL y OSBORNE, seguida de descompresión a tiempos variables. Se comprueba como los fenó- menos regenerarávos-reparativos guardan relación con el tiempo de compresión y con el que transcurre desde la retirada del sistema de compresión. A mayor tiempo de compresión se acentúan los fenómenos alterativos y el edema, mientras que, cuanto más tiempo transcurre desde la retirada del sistema, tanto mayor es la regresión de los fenómenos compresivos, cuyo tope viene dado por grados irreversibles de lesión inicial.A40 rats study was made with a sciatic nerve compression, using a variation of Weisl and Osborne method, followed of descompression at diferent times. The nerve regeneration and reparation depends of the compression time and of the since descompression is made. The nerve alteration and the edema wa s bigger with a longer time of comprenssion. The more time was since descompresión, more was the nerve regeneration. The limit was the irreversible initial lesión

    Evaluation of Enzyme Additives on the Nutritional Use of Feeds with a High Content of Plant Ingredients for Mugil cephalus

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    The Mugilidae are a group of fish with a great interest for aquaculture due to their omnivorous profile, rapid growth, and resistance to environmental variations. The selection of feed ingredients for these species is currently focused on an extensive use of plant by-products, with this being limited by their content in anti-nutritive factors (mainly phytate and non-starch polysaccharides; NSPs). Nevertheless, specific enzymes can be used to counteract some of those negative effects. In the present study, the effect of pretreating two high-plant feeds with a mixture of enzymes (glucanases + phytase) on the digestive use of protein and phosphorus by juvenile mullets (Mugil cephalus) was assessed using both in vitro and in vivo assays. The enzymatic treatment significantly modified the potential bioavailability of some nutrients, such as a reduction of sugars, pentoses, and phytic phosphorus. Also, it increased the digestibility of protein in one of the feeds but reduced that of phosphorus in both of them. The potential usefulness of enzyme treatment and the information provided by the two types of assays are discusse

    Novel educational assessment for building structures: Automatic evaluation of on-line graphics

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    This article presents a new automatic evaluation for on-line graphics, its application and the numerous advantages achieved applying this developed correcting method. The software application developed by the Innovation in Education Group “E4”, from the Technical University of Madrid, is oriented for the online self-assessment of the graphic drawings that students carry out as continuous training. The adaptation to the European Higher Educational Area is an important opportunity to research about the possibilities of on-line education assessment. In this way, a new software tool has been developed for continuous self-testing by undergraduates. Using this software it is possible to evaluate the graphical answer of the students. Thus, the drawings made on-line by students are automatically corrected according to the geometry (straight lines, sloping lines or second order curves) and by sizes (depending on the specific values which define the graphics)

    Forest Ecosystem Services: An Analysis of Worldwide Research

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    The relevance of forests to sustain human well-being and the serious threats they face have led to a notable increase of research works on forest ecosystem services during the last few years. This paper analyses the worldwide research dynamics on forest ecosystem services in the period from 1998 to 2017. A bibliometric analysis of 4284 articles was conducted. The results showed that the number of published research articles has especially increased during the last five years. In total, 68.63% of the articles were published in this period. This research line experiences a growing trend superior to the general publishing trend on forest research. In spite of this increase, its relative significance within the forest research is still limited. The most productive subject areas corresponded to Environmental Science, Agricultural and Biological Sciences and Social Sciences Economic topics are understudied. The scientific production is published in a wide range of journals. The three first publishing countries are United States, China and the United Kingdom. The most productive authors are attached to diverse research centres and their contributions are relatively recent. A high level of international cooperation has been observed between countries, institutions and authors. The findings of this study are useful for researchers since they give them an overview of the worldwide research trends on forest ecosystem services
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