15 research outputs found
Receptors for Hyaluronic Acid and Poliovirus: A Combinatorial Role in Glioma Invasion?
Background: CD44 has long been associated with glioma invasion while, more recently, CD155 has been implicated in playing a similar role. Notably, these two receptors have been shown closely positioned on monocytes. Methods and Findings: In this study, an up-regulation of CD44 and CD155 was demonstrated in established and earlypassage cultures of glioblastoma. Total internal reflected fluorescence (TIRF) microscopy revealed close proximity of CD44 and CD155. CD44 antibody blocking and gene silencing (via siRNA) resulted in greater inhibition of invasion than that for CD155. Combined interference resulted in 86 % inhibition of invasion, although in these investigations no obvious evidence of synergy between CD44 and CD155 in curbing invasion was shown. Both siRNA-CD44 and siRNA-CD155 treated cells lacked processes and were rounder, while live cell imaging showed reduced motility rate compared to wild type cells. Adhesion assay demonstrated that wild type cells adhered most efficiently to laminin, whereas siRNA-treated cells (p,0.0001 for both CD44 and CD155 expression) showed decreased adhesion on several ECMs investigated. BrdU assay showed a higher proliferation of siRNA-CD44 and siRNA-CD155 cells, inversely correlated with reduced invasion. Confocal microscopy revealed overlapping of CD155 and integrins (b1, avb1 and avb3) on glioblastoma cell processes whereas siRNAtransfected cells showed consequent reduction in integrin expression with no specific staining patterns. Reduced expression of Rho GTPases, Cdc42, Rac1/2/3, RhoA and RhoB, was seen in siRNA-CD44 and siRNA-CD155 cells. In contrast t
Estudio de pre factibilidad para la instalaciĂłn de una planta de producciĂłn de arena sĂlice para uso industrial
TesisLa arena sĂlice está compuesta primordialmente de silicio, bajo la forma de Ăłxido de silicio, la cual es conocida como “Arena de Cuarzo”. El silicio que se obtiene de la arena sĂlice es una materia prima muy valiosa para la elaboraciĂłn de productos industriales, por ejemplo los chips de ordenador ya que es un semiconductor. La capacidad de controlar las propiedades elĂ©ctricas del silicio y su abundancia en la naturaleza han posibilitado su desarrollo y aplicaciĂłn en diferentes industrias, como en la electrĂłnica, utilizada para la elaboraciĂłn de los transistores y circuitos integrados.
En general, la arena sĂlice es un recurso relativamente abundante en el paĂs, de razonables perspectivas geolĂłgicas que se explotan en volĂşmenes de producciĂłn de mediana y baja escala, para el estudio en menciĂłn la materia prima será originaria de Curicaca (El Rosario) provincia de JunĂn, donde existen abundantes yacimientos de arena sĂlice, sin embargo corresponden a unas cuarcitas muy descompuestas por lo que la granulometrĂa de la arena no es adecuada para su uso directo.
La importancia de desarrollar el tema radica en la gran demanda de arena sĂlice por el mercado nacional que se proyecta a una demanda tambiĂ©n a nivel internacional (Colombia) segĂşn el Ministerio de EnergĂa y Minas, asĂ como las pocas instalaciones adecuadas para producir fracciones granulomĂ©tricas especĂficas destinadas a mercados industriales tan diversos como: Filtros de agua, perforaciones, fundiciĂłn, vidrio, morteros, plantas Potabilizadoras, pisos de cerámica, pinturas, resinas, loza, epoxi, campos deportivos (futbol, golf, paddle, tenis, etc.), piletas de nataciĂłn; donde la arena sĂlice es utilizada como materia prima debido a sus importantes propiedades fĂsicas y quĂmicas, destacándose especialmente su dureza, alto punto de fusiĂłn, piezoelectricidad, piroelectricidad y transparencia, por tal razĂłn se considera que realizar un estudio de pre-factibilidad para la instalaciĂłn de una planta de producciĂłn de arena sĂlice para uso industrial a partir de la arena sĂlice extraĂda de las canteras, el cual tiene granulometrĂas diferentes que no pueden ser utilizadas directamente, es relevante, ya que este proyecto contará con estudios de mercado, tĂ©cnico, financiero y econĂłmico a fin de analizar la viabilidad tĂ©cnica y econĂłmica para producir arena sĂlice con composiciĂłn optima segĂşn las normas establecidas para cada producto en sus diferentes aplicaciones industriales, como por ejemplo la Norma AFS (American Foundrymen’s Society), para FundiciĂłn
Nonsynaptic GABA signaling in postnatal subventricular zone controls proliferation of GFAP-expressing progenitors
Glycine receptors control the generation of projection neurons in the developing cerebral cortex
The development of the cerebral cortex requires coordinated regulation of proliferation, specification, migration and differentiation of cortical progenitors into functionally integrated neurons. The completion of the neurogenic program requires a dynamic interplay between cell intrinsic regulators and extrinsic cues, such as growth factor and neurotransmitters. We previously demonstrated a role for extrasynaptic glycine receptors (GlyRs) containing the α2 subunit in cerebral cortical neurogenesis, revealing that endogenous GlyR activation promotes interneuron migration in the developing cortical wall. The proliferative compartment of the cortex comprises apical progenitors that give birth to neurons directly or indirectly through the generation of basal progenitors, which serve as amplification step to generate the bulk of cortical neurons. The present work shows that genetic inactivation of Glra2, the gene coding the α2 subunit of GlyRs, disrupts dorsal cortical progenitor homeostasis with an impaired capability of apical progenitors to generate basal progenitors. This defect results in an overall reduction of projection neurons that settle in upper or deep layers of the cerebral cortex. Overall, the depletion of cortical neurons observed in Glra2-knockout embryos leads to moderate microcephaly in newborn Glra2-knockout mice. Taken together, our findings support a contribution of GlyR α2 to early processes in cerebral cortical neurogenesis that are required later for the proper development of cortical circuits