Up-Regulation of Tumor Necrosis Factor Superfamily Genes in Early Phases of Photoreceptor Degeneration

We used quantitative real-time PCR to examine the expression of 112 genes related to retinal function and/or belonging to known pro-apoptotic, cell survival, and autophagy pathways during photoreceptor degeneration in three early-onset canine models of human photoreceptor degeneration, rod cone dysplasia 1 (rcd1), X-linked progressive retinal atrophy 2 (xlpra2), and early retinal degeneration (erd), caused respectively, by mutations in PDE6B, RPGRORF15, and STK38L. Notably, we found that expression and timing of differentially expressed (DE) genes correlated with the cell death kinetics. Gene expression profiles of rcd1 and xlpra2 were similar; however rcd1 was more severe as demonstrated by the results of the TUNEL and ONL thickness analyses, a greater number of genes that were DE, and the identification of altered expression that occurred at earlier time points. Both diseases differed from erd, where a smaller number of genes were DE. Our studies did not highlight the potential involvement of mitochondrial or autophagy pathways, but all three diseases were accompanied by the down-regulation of photoreceptor genes, and up-regulation of several genes that belong to the TNF superfamily, the extrinsic apoptotic pathway, and pro-survival pathways. These proteins were expressed by different retinal cells, including horizontal, amacrine, ON bipolar, and Müller cells, and suggest an interplay between the dying photoreceptors and inner retinal cells. Western blot and immunohistochemistry results supported the transcriptional regulation for selected proteins. This study highlights a potential role for signaling through the extrinsic apoptotic pathway in early cell death events and suggests that retinal cells other than photoreceptors might play a primary or bystander role in the degenerative process

Immunolocalization of Ciliary Neurotrophic Factor Receptor α (CNTFRα) in Mammalian Photoreceptor Cells

PURPOSE: To characterize the site of expression of the α subunit of the receptor for ciliary neurotrophic factor (CNTFRα) in the retina of a variety of mammalian species, and determine whether CNTFRα is localized to photoreceptor cells. METHODS: The cellular distribution of CNTFRα (protein) was examined by immunocytochemistry in the adult retinas of several mammalian species that included mouse, rat, dog, cat, sheep, pig, horse, monkey, and human. Developing retinas from 3-day-old and 6-day-old rats were also included in this study. The molecular weight of CNTFRα in rat, dog, cat, pig, and human retinas was determined by immunoblotting. RESULTS: CNTFRα immunolabeling was present in the retina of all species. A common pattern was observed in all species, and represented labeling of the nerve fiber layer (NFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), and outer plexiform layer (OPL). CNTFRα did not immunolocalize to photoreceptor cells in both adult and developing rodent retinas, but was consistently observed in both rods and cones of non-rodent species. The molecular weight of CNTFRα in mammalian retinas was approximately 61-64 kDa. CONCLUSIONS: These findings highlight a significant difference in the expression of CNTFRα in the retina of rodent and non-rodent mammalian species. The expression of CNTFRα by rods and cones in non-rodent species may suggest a direct mechanism of action if CNTF administration results in photoreceptor rescue

Age-Dependent Disease Expression Determines Remodeling of the Retinal Mosaic in Carriers of \u3cem\u3eRPGR\u3c/em\u3e Exon ORFn\u3csub\u3e15\u3c/sub\u3e Mutations

PURPOSE. To characterize the retinal histopathology in carriers of X-linked progressive retinal atrophy (XLPRA1 and XLPRA2), two canine models of X-linked retinitis pigmentosa caused, respectively, by a stop and a frameshift mutation in RPGRORF15. METHODS. Retinas of XLPRA2 and XLPRA1 carriers of different ages were processed for morphologic evaluation, TUNEL assay, and immunohistochemistry. Cell-specific markers were used to examine retinal remodeling events. RESULTS. A mosaic pattern composed of patches of diseased and normal retina was first detected in XLPRA2 carriers at 4.9 weeks of age. A peak of photoreceptor cell death led to focal rod loss; however, in these patches an increased density of cones was found to persist over time. Patches of disease gradually disappeared so that by 39 weeks of age the overall retinal morphology, albeit thinner, had improved lamination. In older XLPRA2 carriers (≥8.8 years), extended regions of severe degeneration occurred in the peripheral/mid-peripheral retina. In XLPRA1 carriers, opsin mislocalization and rare events of rod death were detected by TUNEL assay at 20 weeks of age; however, only patchy degeneration was seen by 1.4 years and was still apparent at 7.8 years. CONCLUSIONS. The time of onset and the progression of the disease differed between the two models. In the early-onset form (XLPRA2) the morphologic appearance of the retinal mosaic changed as a function of age, suggesting that structural plasticity persists in the early postnatal canine retina as mutant photoreceptors die. In the late-onset form (XLPRA1), patches of disease persisted until later ages

Territoriality and Commerce: Political Conflict Over the Panama Canal in Geographic Perspective.

This dissertation examines the recurring conflict between the United States and the Republic of Panama regarding the Canal and the Canal Zone by analyzing three salient geographic issues: first, the extent to which international commerce or national security required the building of a canal in Central America; second, ambiguities arising out of notions of sovereignty and extraterritoriality in United States constitutional law; and third, the political controversies between an inland society and a maritime society in Panama itself The theoretical implications of Edward Fox\u27s work in his geographic history of French politics and the works of Panamanian historians and sociologists studying eighteenth and nineteenth-century Panama were used to offer an explanation of Panama\u27s contemporary political relations with the United States. Panama has historically been divided between an inland and a maritime society, with the maritime society tending to be the more politically and economically dominant one. After its independence in 1903, Panama\u27s internal political competition created a situation where all sides felt compelled to assume an antagonistic posture with the United States and demand treaty concessions beyond what might even seem to be within Panama\u27s reasonable national economic interest. The interpositionist role of the United States in Panamanian affairs is the product of a longstanding commitment. The United States has assumed sole responsibility for protecting the neutrality of interoceanic communication across Panama since the middle of the nineteenth century. The goal was to prevent European powers from threatening a maritime choke point affecting U.S. national security and potential commercial expansion. The project to construct an American Panama Canal was, therefore, a product of commercial as well as military concerns. Contrary to conventional thinking about the nature of U.S.-Panamanian relations, this dissertation examines how the influence of the United States, at times, became the means by which Panamanian opposition leaders leveraged political pressure against internal rivals

La convergencia interdisciplinaria en el contexto educativo de secundaria en la aplicación del principio de corresponsabilidad para mejorar la actividad del docente como intelectual orgánico

This article presents the central ideas of the theoretical frame of reference that served for the theoretical construction of the fundamental educational ideas that guided the reference text “The sense of the principle of co-responsibility in the face of the pedagogical practices of teachers, the role of the family and educational policy ”to aspire to the Doctorate in education from the Technological University of Pereira. In this sense, the present text indicates the interdisciplinary and theoretical convergence that allows sustaining the need for the principle of co-responsibility and fundamental function that turns the teacher into an “organic intellectual” in the task of the educational act in exercise of the execution of the right to quality of education. education, which challenges him to contribute with his leadership to agency processes of change.El presente artículo expone las ideas centrales del marco de referencia teórico que sirvieron para la construcción teórica de las ideas educativas fundamentales que orientaron el texto de referencia “El sentido del principio de corresponsabilidad frente a las prácticas pedagógicas de los docentes, el papel de la familia y la política educativa” para aspirar el Doctorado en educación de la Universidad Tecnológica de Pereira. En este sentido el presente texto señala la convergencia interdisciplinaria y teórica que permite orientar la necesidad del principio de corresponsabilidad y función fundamental que convierte al docente en “intelectual orgánico” en el quehacer del acto educativo en ejercicio de la ejecución del derecho a la calidad de la educación, que lo interpela por contribuir con su liderazgo a agenciar procesos de cambio

La convergencia interdisciplinaria en el contexto educativo de secundaria en la aplicación del principio de corresponsabilidad para mejorar la actividad del docente como intelectual orgánico

This article presents the central ideas of the theoretical frame of reference that served for the theoretical construction of the fundamental educational ideas that guided the reference text “The sense of the principle of co-responsibility in the face of the pedagogical practices of teachers, the role of the family and educational policy ”to aspire to the Doctorate in education from the Technological University of Pereira. In this sense, the present text indicates the interdisciplinary and theoretical convergence that allows sustaining the need for the principle of co-responsibility and fundamental function that turns the teacher into an “organic intellectual” in the task of the educational act in exercise of the execution of the right to quality of education. education, which challenges him to contribute with his leadership to agency processes of change.El presente artículo expone las ideas centrales del marco de referencia teórico que sirvieron para la construcción teórica de las ideas educativas fundamentales que orientaron el texto de referencia “El sentido del principio de corresponsabilidad frente a las prácticas pedagógicas de los docentes, el papel de la familia y la política educativa” para aspirar el Doctorado en educación de la Universidad Tecnológica de Pereira. En este sentido el presente texto señala la convergencia interdisciplinaria y teórica que permite orientar la necesidad del principio de corresponsabilidad y función fundamental que convierte al docente en “intelectual orgánico” en el quehacer del acto educativo en ejercicio de la ejecución del derecho a la calidad de la educación, que lo interpela por contribuir con su liderazgo a agenciar procesos de cambio

Riesgos del uso de las redes sociales en estudiantes del nivel secundario de la Institución Educativa Nº 157 “Cap. FAP. José Abelardo Quiñones”, San Juan de Lurigancho -2017

La investigación tuvo como objetivo determinar el nivel de riesgo del uso de las redes sociales en los estudiantes del nivel secundario de la Institución Educativa nº 157 “Cap. FAP. José Abelardo Quiñones”, San Juan de Lurigancho – 2017, se realizó a través del enfoque cuantitativo, tipo básica, nivel descriptivo con un diseño de trabajo no experimental de corte transversal. La muestra estuvo representada por 146 estudiantes. La técnica empleada fue a través de una encuesta y su instrumento fue un cuestionario, para el procesamiento de datos se utilizó el programa estadístico SPSS versión 23, los resultados mostraron que el 54,79 % de estudiantes indican que nivel de riesgo es bajo y un 5,48 % de estudiantes muestran que el nivel de riesgo es alto

Intravitreal Injection of Ciliary Neurotrophic Factor (CNTF) Causes Peripheral Remodeling and Does Not Prevent Photoreceptor Loss in Canine \u3cem\u3eRPGR\u3c/em\u3e Mutant Retina

Ciliary neurotrophic factor (CNTF) rescues photoreceptors in several animal models of retinal degeneration and is currently being evaluated as a potential treatment for retinitis pigmentosa in humans. This study was conducted to test whether CNTF prevents photoreceptor cell loss in XLPRA2, an early onset canine model of X-linked retinitis pigmentosa caused by a frameshift mutation in RPGR exon ORF15. Four different treatment regimens of CNTF were tested in XLPRA2 dogs. Under anesthesia, the animals received at different ages an intravitreal injection of 12 μg of CNTF in the left eye. The right eye served as a control and was injected with a similar volume of phosphate buffered saline (PBS). Ocular examinations were performed regularly during the treatment periods. At termination, the dogs were euthanatized, eyes collected and the retinas were processed for embedding in optimal cutting temperature (OCT) medium. The outer nuclear layer (ONL) thickness was evaluated on H&E sections and values in both CNTF- and PBS-treated eyes were compared. Morphologic alterations in the peripheral retina were characterized by immunohistochemistry using cell-specific markers. Cell proliferation in the retinas was examined on semi-thin plastic sections, and by BrdU pulse-labeling and Ki67 immunohistochemistry on cryosections. All CNTF-treated eyes showed early clinical signs of corneal epitheliopathy, subcapsular cataracts and uveitis. No statistically significant difference in ONL thickness was seen between the CNTF- and PBS-injected eyes. Prominent retinal remodeling that consisted in an abnormal increase in the number of rods, and in misplacement of some rods, cones, bipolar and Müller cells, was observed in the peripheral retina of CNTF-treated eyes. This was only seen when CNTF was in injected before the age at which the canine retina reaches full maturation. In XLPRA2 dogs, intravitreal injections of CNTF failed to prevent photoreceptors from undergoing cell death in the central and mid-peripheral retina. CNTF also caused ocular side-effects and morphologic alterations in the periphery that were consistent with cell dedifferentiation and proliferation. Our findings suggest that some inherited forms of retinal degeneration may not respond to CNTF\u27s neuroprotective effects