Problemas de la visión binocular en las aulas de Educación Infantil

El sistema visual es uno de los sentidos más importantes que tenemos, ya que nos permite una interacción continua con el mundo que nos rodea. De pequeños, al igual que aprendemos a hablar y andar, debemos aprender a mirar y a ver. Poco a poco el cerebro irá configurando nuestro esquema visual para el procesado de las imágenes. Los primeros años de vida son fundamentales ya que se termina de desarrollar el sistema visual. Por ello, los docentes de Educación Infantil tendremos que estar atentos a cualquier señal que nos indique que este desarrollo se ve afectado en nuestros alumnos. En muchas ocasiones, vemos como bajan sus rendimientos escolares y buscamos causas que lo justifique. Entre éstas tenemos los problemas visuales como el “ojo vago” o las forias que pueden afectar a la visión estereoscópica. Por ello, crearemos un programa para detectar las principales alteraciones de la visión binocular y un plan de ejercicios que pueda disminuir este déficit con terapia visual

Glía envolvente olfatoria:resultados e implementación de su trasplante en lesiones medulares

La incapacidad e irreversibilidad que producen las lesiones medulares genera el interés por tratar de establecer un mejor pronóstico y tratamiento para estos pacientes. Para ello, es necesario conocer los mecanismos establecidos tras la lesión medular. Normalmente, estos mecanismos inhiben la capacidad regenerativa axonal y evita que las posibles terapias que pudieran revertir estos cambios sean eficaces. Las células de glía envolvente olfatoria (OEG) ayudan a los axones del nervio olfatorio a alcanzar el bulbo olfatorio en el sistema nervioso central. Estas células se han utilizado experimentalmente para el tratamiento de lesiones, gracias a su actividad regenerativa y reparativa que tienen sobre el nervio olfatorio. El procedimiento que se utiliza consiste en extraer las OEG de la mucosa o bulbo olfatorio, cultivarlas y trasplantarlas en la zona de la lesión. El objetivo de esta revisión es mostrar la metodología utilizada para la obtención de OEG, su trasplante y los resultados que se han obtenido en diferentes especies. Por otro lado, se analiza la utilización de coadyuvantes para que sea efectivo el trasplante de OEG y las estrategias que pudieran ser complementarias y potenciadoras de su actividad. Finalmente, se hace mención a los últimos trabajos que han utilizado esta terapia para tratar lesiones medulares en pacientes y las noticias contradictorias que se tiene sobre su utilización. <br /

Hippocampal GABAergic Synapses Possess the Molecular Machinery for Retrograde Nitric Oxide Signaling

Nitric oxide (NO) plays an important role in synaptic plasticity as a retrograde messenger at glutamatergic synapses. Here we describe that, in hippocampal pyramidal cells, neuronal nitric oxide synthase (nNOS) is also associated with the postsynaptic active zones of GABAergic symmetrical synapses terminating on their somata, dendrites, and axon initial segments in both mice and rats. The NO receptor nitric oxide-sensitive guanylyl cyclase (NOsGC) is present in the brain in two functional subunit compositions: alpha1beta1 and alpha2beta1. The beta1 subunit is expressed in both pyramidal cells and interneurons in the hippocampus. Using immunohistochemistry and in situ hybridization methods, we describe that the alpha1 subunit is detectable only in interneurons, which are always positive for beta1 subunit as well; however, pyramidal cells are labeled only for beta1 and alpha2 subunits. With double-immunofluorescent staining, we also found that most cholecystokinin- and parvalbumin-positive and smaller proportion of the somatostatin- and nNOS-positive interneurons are alpha1 subunit positive. We also found that the alpha1 subunit is present in parvalbumin- and cholecystokinin-positive interneuron terminals that establish synapses on somata, dendrites, or axon initial segments. Our results demonstrate that NOsGC, composed of alpha1beta1 subunits, is selectively expressed in different types of interneurons and is present in their presynaptic GABAergic terminals, in which it may serve as a receptor for NO produced postsynaptically by nNOS in the very same synapse

Ultrastructural characteristics of Glial and Interstitial cells of Cajal in the Lizard intestine: presence of primary cilium

In mammals, enteric nervous system consists of neurons and glial cells which are mainly organized in two ganglionated plexuses: the myenteric plexus, and the inner and outer submucosal plexuses. Enteric glial cells establish a direct contact with neurons; their cytoplasm prolongations surround the unmyelinated axons. The interstitial cells of Cajal (ICCs) are located around enteric ganglia and in both muscular layers forming an interconnected network. It is now known that some ICCs and glial cells in mammals present a single cilium but its presence in the rest of vertebrate classes has been not still demonstrated. The aim of the present study is to characterize, at the ultrastructural level, the enteric glial cells and ICCs in the lizard intestine. Material and methods: We used ten adult lizards Podareis hispanica (Reptilia). Small and large intestine wall samples were fixed with 2.5% glutaraldehyde in PB buffer (pH 7.3) and routinely processed for TEM visualization. Results: Lizard intestinal ganglia show a lower number of neurons than those from mammals. Glial cells were smaller than neurons and they showed dark nuclei because of their condénsate heterochromatin. These glial cells surround axons mainly containing mixed both cholinergic and peptidergic vesicles. Occasionally, some axons were found surrounded by myelin sheaths. We found ICCs around enteric ganglia of the myenteric plexus. They present triangular or spindle forms and a very voluminous nucleus, with scarce marginal heterochromatin, surrounded by a thin perinuclear cytoplasm that expands with long cytoplasmic processes. ICC processes penetrate and connect with other ICCs located in the connective tissue of the both muscle layers by gap-like junctions forming a three-dimensional network. In addition, we demónstrate the presence of a primary cilium in ICCs as well as in glial cells. We describe their ultraestructural features: basal foot and cap in the basal corpuscle, (9+0) axonema, and a characteristic domain of membrane: the ciliary pocket. Conclusions: Our data support that the single cilium is present in both kinds of cells and consequently, this is a phylogenetically preserved structure