The role of WNT singling activation and its blockage in the focal retinal lesion of Ccl2-/-/Cx3cr1-/- mice with and without rd8 background

Purpose: The canonical Wnt signaling is activated by retinal injury. Under disease conditions, the Wnt mediates inflammatory responses. Inflammation has been detected in age-related macular degeneration (AMD) retinas and Ccl2-/-/Cx3cr1-/- (DKO) mice with or without rd8 background, a model with progressive AMD-like lesions including focal photoreceptor/RPE degeneration and A2E accumulation. We evaluated the effects of Wnt-β-catenin activation and an antibody against LRP6, the co-receptor of Wnt on these two models.

Methods: anti-LRP6 antibody (2F1, 1 μl of 5 μg/μL) was intravitreally injected into the right eyes in 3 separate experiments (DKOrd8, N=35; DKO, N=10). The left eyes were injected with mouse IgG as controls. Fundoscopy was taken before injection and sequentially monthly after injection. Two months after injection, light-adapted ERG responses were recorded; then the eyes were harvested for histopathology, the determination of retinal A2E, and molecular analysis. The microarray of ocular mRNA of 92 Wnt genes was compared between the treated and the control eyes. The phosphorylated types of LRP6 and β-catenin and endogenous forms of the proteins were assayed by Western blotting.

Results: For DKOrd8 mice, the fundus showed a slower progression or alleviation of retinal lesions in the right eyes as compared to the left eyes. Among 35 pairs of eyes, 26 (74.3%) were improved, 7 (20%) stayed the same and 2 (5.7%) remained progressing. Histology confirmed the clinical observation. Light-adapted ERG of the treated eyes exhibited larger amplitudes compared to control eyes (n=6), with greater improvements under UV light stimulus. There was a significantly lower A2E in the treated eyes compared to controls. Microarray of 92 Wnt genes expression pattern was similar in both eyes. Western blotting indicated local administration of 2F1 antibody to suppress the activation of Wnt pathway in the retina. For DKO mice, the treatment improved ERG but less effect on RPE degeneration.

Conclusions: The canonical Wnt signaling plays a role in the focal retina lesion of both DKOrd8 and DKO mice; and intravitreal anti-LRP6 antibody might be neuroprotective via deactivation of canonical Wnt pathway.

High-resolution spatial mapping of changes in the neurochemical profile after focal ischemia in mice.

After ischemic stroke, the ischemic damage to brain tissue evolves over time and with an uneven spatial distribution. Early irreversible changes occur in the ischemic core, whereas, in the penumbra, which receives more collateral blood flow, the damage is more mild and delayed. A better characterization of the penumbra, irreversibly damaged and healthy tissues is needed to understand the mechanisms involved in tissue death. MRSI is a powerful tool for this task if the scan time can be decreased whilst maintaining high sensitivity. Therefore, we made improvements to a (1) H MRSI protocol to study middle cerebral artery occlusion in mice. The spatial distribution of changes in the neurochemical profile was investigated, with an effective spatial resolution of 1.4 μL, applying the protocol on a 14.1-T magnet. The acquired maps included the difficult-to-separate glutamate and glutamine resonances and, to our knowledge, the first mapping of metabolites γ-aminobutyric acid and glutathione in vivo, within a metabolite measurement time of 45 min. The maps were in excellent agreement with findings from single-voxel spectroscopy and offer spatial information at a scan time acceptable for most animal models. The metabolites measured differed with respect to the temporal evolution of their concentrations and the localization of these changes. Specifically, lactate and N-acetylaspartate concentration changes largely overlapped with the T(2) -hyperintense region visualized with MRI, whereas changes in cholines and glutathione affected the entire middle cerebral artery territory. Glutamine maps showed elevated levels in the ischemic striatum until 8 h after reperfusion, and until 24 h in cortical tissue, indicating differences in excitotoxic effects and secondary energy failure in these tissue types. Copyright © 2011 John Wiley & Sons, Ltd.

The effect of a segmental, localized lower limb cooling protocol on muscular strength and balance

The human neuromuscular system is susceptible to changes within the thermal environment. Cold extrinsic temperatures can significantly reduce muscle and nervous system function and communication, which can have consequences for motor performance. A repeated measures design protocol exposed participants to a 12°C cold water immersion (CWI) up to the ankle, knee, and hip to determine the effect that reduced skin and muscle temperature had on balance and strength task execution. Although a linear reduction in the ability to perform balance tasks was seen from the control condition through to the hip CWI, results from the study indicated a significant reduction in dynamic balance (Star Excursion Balance Test reach distance) performance from only the hip CWI (P<0.05). This reduced performance could have been due to an increase in joint stiffness, increased agonist-antagonist co-contraction, and/or reduced isokinetic muscular strength. Reduced physical performance due to cold temperature could negatively impact outdoor recreational athletics.

Planeación punto focal de la auditoría financiera por Manuel Coello Ríos

Tesis [Maestría en Contaduría Pública con Especialidad en Auditoría) U.A.N.L.

fNIRS-EEG study of focal interictal epileptiform discharges

Functional near-infrared spectroscopy (fNIRS) acquired with electroencephalography (EEG) is a relatively new non-invasive neuroimaging technique with potential for long term monitoring of the epileptic brain. Simultaneous EEG-fNIRS recording allows the spatio-temporal reconstruction of the hemodynamic response in terms of the concentration changes in oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbR) associated with recorded epileptic events such as interictal epileptic discharges (IEDs) or seizures. While most previous studies investigating fNIRS in epilepsy had limitations due to restricted spatial coverage and small sample sizes, this work includes a sufficiently large number of channels to provide an extensive bilateral coverage of the surface of the brain for a sample size of 40 patients with focal epilepsies. Topographic maps of significant activations due to each IED type were generated in four different views (dorsal, frontal, left and right) and were compared with the epileptic focus previously identified by an epileptologist. After excluding 5 patients due to the absence of IEDs and 6 more with mesial temporal foci too deep for fNIRS, we report that significant HbR (respectively HbO) concentration changes corresponding to IEDs were observed in 62% (resp. 38%) of patients with neocortical epilepsies. This HbR/HbO response was most significant in the epileptic focus region among all the activations in 28%/21% of patients.

Especificidad de la relación entre la conciencia segmental y el aprendizaje de la lecto-escritura en la dislexia.

Buscar cuál es la importancia del aprendizaje lecto-escritor en la relación establecida por los niños entre el lenguaje escrito y el oral a nivel fonológico, como base de la hipótesis: los problemas lecto-escritores de los niños disléxicos provocados por la falta de desarrollo de la conciencia segmental. Estudiar que muestran una clara oposición a una instrucción que mejore su aprendizaje. Población: tres colegios públicos de Salamanca. Niveles segundo y tercero de EGB. 8 Niños, 4 varones de CI medio-bajo (DX) y 4 disléxicos de CI normal (RT). Estudio teórico sobre el aprendizaje de la lecto-escritura. Destaca la importancia del procesamiento fonológico y la conciencia segmental. Establece un relación bidireccional entre la conciencia segmental y el aprendizaje de la lecto-escritura. Deja teóricamente demostrado que el entrenamiento en tareas que desarrollan la conciencia segmental favorece el aprendizaje de la lectura, siendo de importancia para los niños disléxicos cuya dificultad se debe a la falta de este desarrollo. Hace una detallada fundamentación teórica: Bradley y Brayant (1978) sobre la dislexia proponiendo el modelo de adquisición de la lectura de Uta Frith como soporte teórico de su hipótesis. Utiliza el programa 'Escribir una palabra' (Sánchez, Rueda y Orrantía 1989) como entrenamiento de la conciencia segmental. Programa basado en el concepto de resistencia a la instrucción ligado al concepto de interacción de Vygotski (1979). Selección: WISC. Tale (análisis de la lectura y la escritura). Cuestionario para medir el nivel de metalenguaje (Rueda y Sánchez,1988). Intervención: programa de instrucción, hoja de ayudas y lista de palabras o pseudopalabras. Diseño experimental. ANOVA de un factor. Análisis particular de cada uno de los ocho casos. 'Escribir una palabra'. Los niños DX necesitaron mayor número de ayudas específicas a la conciencia segmental cuando tenían que realizar aquellos pasos del programa que suponen segmentación de los fonos. No aparecen diferencias importantes en cuanto a ayudas necesarias en las categorías de colaboración y uso del código. Los niños del grupo RT no necesitan mayor número de ayudas no específicas que los disléxicos. El problema de los niños disléxicos es que no son capaces de segmentar cuando se les instruye para hacerlo, presentan resistencia a la instrucción por ello, debe insistirse en el desarrollo de la conciencia segmental, pues es la pieza clave para el aprendizaje lectoescritor, de extrema importancia pues es lo que permite acceder al niño al conocimiento.

Conocimiento segmental y dislexia : efectos de la instrucción en la adquisición y mantenimiento del conocimiento fonémico en niños disléxicos.

Conocer los componentes de la instrucción que repercuten en la mejora de las dificultades que presentan los niños disléxicos. Estudiar la evaluación a lo largo del tiempo de los sujetos disléxicos. Específicamente, conocer si los sujetos instruidos en un programa de habilidades de segmentación obtienen conocimiento fonémico y son capaces de mantener ese conocimiento a lo largo del tiempo. Se presentan cuatro estudios. En el primer estudio participan 28 sujetos, categorizados como disléxicos, y con edades comprendidas entre los 7 y los 11 años. Los niños pertenecen a cuatro colegios de la ciudad de Salamanca. En el segundo estudio participan 25 sujetos, categorizados como disléxicos y con edades comprendidas entre los 8 y los 12 años. En el tercer estudio participan 21 sujetos disléxicos, con edades comprendidas entre los 8 y 11 años. En el cuarto estudio participan 18 sujetos, categorizados como disléxicos, con edades comprendidas entre los 7 y 10 años. En los estudios primero, segundo y tercero se utiliza un diseño experimental antes después siendo la variable independiente el tipo de tratamiento de instrucción en la lectura: programa de adición de fonos, programa de escribir una palabra, programa de instrucción en lectura y grupo control (sin tratamiento). Las variables dependientes son el conocimiento fonémico y el aprendizaje de la lectura y escritura. El cuarto estudio es de carácter longitudinal y experimental, siendo la variable independiente la instrucción (recibida o ausente) en tareas de lectoescritura; y las variables dependientes son: el conocimiento fonémico y el aprendizaje de la lectura y escritura. Los instrumentos utilizados se clasifican en dos categorías: los empleados para la selección de la muestra de niños disléxicos (entrevista, test WISC y test de análisis de lectoescritura, TALE) y las pruebas aplicadas para medir la influencia del tratamiento en las variables dependientes: test de análisis de lectoescritura (TALE) y cuestionario para medir el conocimiento fonémico. Se utilizan diversas pruebas de contraste de hipótesis: prueba de Chi cuadrado, análisis de varianza y covarianza, prueba t de Student, análisis de correlación de Pearson y análisis de conglomerados. El estudio primero concluye que el componente de segmentación es un elemento fundamental en la producción de mejoras significativas en conocimiento fonémico. Los sujetos instruidos, además de mejorar su nivel de conocimiento fonémico, también mejoran en la realización de las tareas de lectoescritura (dictado). Los resultados del segundo estudio muestran que los sujetos que participan en los programas de instrucción consiguen generalizar las habilidades de segmentación a otro tipo de tareas de segmentación más complejas y no instruidas. Los resultados del estudio tercero son reiterativos y consistentes con los estudios precedentes. El cuarto estudio muestra que el conocimiento fonémico adquirido gracias a un período de instrucción sufre un retroceso inmediato y que la edad no repercute en una mejora en este criterio. Por otro lado, los sujetos no aprovechan la instrucción de la misma forma pudiendo llegar a diferenciarse dos tipos: los que avanzan y los que presentan cierta resistencia a la instrucción. Resistencia que puede desaparecer al continuar instruyéndoles. Se comprueba la especial relevancia que para el aprendizaje de la lectura en un sistema alfabético posee el conocimiento fonológico. De los componentes utilizados en la instrucción (habilidades de segmentación, código y decodificación) se constata que es el componente de segmentación el de mayor relevancia.

Heat shock protein 27 is the major differentially phosphorylated protein involved in renal epithelial cellular stress response and controls focal adhesion organization and apoptosis

We used two-dimensional difference gel electrophoresis to determine early changes in the stress-response pathways that precede focal adhesion disorganization linked to the onset of apoptosis of renal epithelial cells. Treatment of LLC-PK1 cells with the model nephrotoxicant 1,2-(dichlorovinyl)-L-cysteine (DCVC) resulted in a >1.5-fold up- and down-regulation of 14 and 9 proteins, respectively, preceding the onset of apoptosis. Proteins included those involved in metabolism, i.e. aconitase and pyruvate dehydrogenase, and those related to stress responses and cytoskeletal reorganization, i.e. cofilin, Hsp27, and alpha-b-crystallin. The most prominent changes were found for Hsp27, which was related to a pI shift in association with an altered phosphorylation status of serine residue 82. Although both p38 and JNK were activated by DCVC, only inhibition of p38 with SB203580 reduced Hsp27 phosphorylation, which was associated with accelerated reorganization of focal adhesions, cell detachment, and apoptosis. In contrast, inhibition of JNK with SP600125 maintained cell adhesion as well as protection against apoptosis. Active JNK co-localized at focal adhesions after DCVC treatment in a FAK-dependent manner. Inhibition of active JNK localization at focal adhesions did not prevent DCVC-induced phosphorylation of Hsp27. Overexpression of a phosphorylation-defective mutant Hsp27 acted as a dominant negative and accelerated the DCVC-induced changes in the focal adhesions as well as the onset of apoptosis. Our data fit a model whereby early p38 activation results in a rapid phosphorylation of Hsp27, a requirement for proper maintenance of cell adhesion, thus suppressing renal epithelial cell apoptosis.

Heat shock protein 27 is the major differentially phosphorylated protein involved in renal epithelial cellular stress response and controls focal adhesion organization and apoptosis

We used two-dimensional difference gel electrophoresis to determine early changes in the stress-response pathways that precede focal adhesion disorganization linked to the onset of apoptosis of renal epithelial cells. Treatment of LLC-PK1 cells with the model nephrotoxicant 1,2-(dichlorovinyl)-L-cysteine ( DCVC) resulted in a > 1.5-fold up- and down-regulation of 14 and 9 proteins, respectively, preceding the onset of apoptosis. Proteins included those involved in metabolism, i.e. aconitase and pyruvate dehydrogenase, and those related to stress responses and cytoskeletal reorganization, i.e. cofilin, Hsp27, and alpha-b-crystallin. The most prominent changes were found for Hsp27, which was related to a pI shift in association with an altered phosphorylation status of serine residue 82. Although both p38 and JNK were activated by DCVC, only inhibition of p38 with SB203580 reduced Hsp27 phosphorylation, which was associated with accelerated reorganization of focal adhesions, cell detachment, and apoptosis. In contrast, inhibition of JNK with SP600125 maintained cell adhesion as well as protection against apoptosis. Active JNK co-localized at focal adhesions after DCVC treatment in a FAK-dependent manner. Inhibition of active JNK localization at focal adhesions did not prevent DCVC-induced phosphorylation of Hsp27. Overexpression of a phosphorylation-defective mutant Hsp27 acted as a dominant negative and accelerated the DCVC-induced changes in the focal adhesions as well as the onset of apoptosis. Our data fit a model whereby early p38 activation results in a rapid phosphorylation of Hsp27, a requirement for proper maintenance of cell adhesion, thus suppressing renal epithelial cell apoptosis.

Increased protein SUMOylation following focal cerebral ischemia

Stroke is a major cause of death and disability, which involves excessive glutamate receptor activation leading to excitotoxic cell death. We recently reported that SUMOylation can regulate kainate receptor (KAR) function. Here we investigated changes in protein SUMOylation and levels of KAR and AMPA receptor subunits in two different animal stroke models: a rat model of focal ischemia with reperfusion and a mouse model without reperfusion. In rats, transient middle cerebral artery occlusion (MCAO) resulted in a striatal and cortical infarct. A dramatic increase in SUMOylation by both SUMO-1 and SUMO-2/3 was observed at 6h and 24h in the striatal infarct area and by SUMO-2/3 at 24h in the hippocampus, which was not directly subjected to ischemia. In mice, permanent MCAO resulted in a selective cortical infarct. No changes in SUMOylation occurred at 6h but there was increased SUMO-1 conjugation in the cortical infarct and non-ischemic hippocampus at 24h after MCAO. Interestingly, SUMOylation by SUMO-2/3 occurred only outside the infarct area. In both rat and mouse levels of KARs were only decreased in the infarct regions whereas AMPARs were decreased in the infarct and in other brain areas. These results suggest that posttranslational modification by SUMO and down-regulation of AMPARs and KARs may play important roles in the pathophysiological response to ischemia.

Infrared filters for space-flight focal plane array applications

Infrared filters and coatings have been employed on many sensing radiometer instruments to measure the thermal emission profiles and concentrations of certian chemical constituents found in planetary atmospheres. The High Resolution Dynamics Limb Sounder ( HIRDLS) is an example of the most recent developments in limb-viewing radiometry by employing a cooled focal plane detector array to provide simultaneous multi-channel monitoring of emission from gas and aerosols over an altitude range between 8 - 70 km. The use of spectrally selective cooled detectors in focal plane arrays has simplified the optical layout of radiometers, greatly reducing the number of components in the optical train. this has inevitably led to increased demands for the enviromnetal durability of the focal plane filters because of the need to cut sub-millimeter sizes, whilst maintaining an optimal spectral performance. Additionally the remaining refractive optical elements require antireflection coatings which must cover the entire spectral range of the focal plane array channels, in this case 6 to 18µm, with a minimum of reflection and absorption. This paper describes the optical layout and spectral design requirements for filteriong in the HIRDLS instrument, and reports progress on the manufacturing and testing of the sub-millimetre sized cooled filters. We also report on the spectral and environmental performance of prototype wideband antireflection coatings which satisfy the requirements above.