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Pig Retina (pig + retina)
Selected AbstractsThe immunocytochemical localization of connexin 36 at rod and cone gap junctions in the guinea pig retinaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2003Eun-Jin Lee Abstract Connexin 36 (Cx36) is a channel-forming protein found in the membranes of apposed cells, forming the hexameric hemichannels of intercellular gap junction channels. It localizes to certain neurons in various regions of the brain including the retina. We characterized the expression pattern of neuronal Cx36 in the guinea pig retina by immunocytochemistry using specific antisera against Cx36 and green/red cone opsin or recoverin. Strong Cx36 immunoreactivity was visible in the ON sublamina of the inner plexiform layer and in the outer plexiform layer, as punctate labelling patterns. Double-labelling experiments with antibody directed against Cx36 and green/red cone opsin or recoverin showed that strong clustered Cx36 immunoreactivity localized to the axon terminals of cone or close to rod photoreceptors. By electron microscopy, Cx36 immunoreactivity was visible in the gap junctions as well as in the cytoplasmic matrices of both sides of cone photoreceptors. In the gap junctions between cone and rod photoreceptors, Cx36 immunoreactivity was only visible in the cytoplasmic matrices of cone photoreceptors. These results clearly indicate that Cx36 forms homologous gap junctions between neighbouring cone photoreceptors, and forms heterologous gap junctions between cone and rod photoreceptors in guinea pig retina. This focal location of Cx36 at the terminals of the photoreceptor suggests that rod photoreceptors can transmit rod signals to the pedicle of a neighbouring cone photoreceptor via Cx36, and that the cone in turn signals to corresponding ganglion cells via ON and OFF cone bipolar cells. [source] Choroidal neovascularization associated with cancer-associated retinopathyACTA OPHTHALMOLOGICA, Issue 5 2010Giuseppe Querques Abstract. Purpose:, To report an unusual association between cancer-associated retinopathy (CAR) associated with invasive thymoma and choriodal neovascularization (CNV), treated by photodynamic theraphy (PDT). Methods:, A 39-year-old man affected with thymoma and paraneoplastic syndrome (myasthenia gravis and diarrhoea) was observed between October 1997 and September 2007. The patient developed progressive visual dysfunction including bilateral visual acuity loss and concentric constriction of visual fields. Ophthalmological, immunological and systemic examinations were performed. Immunological evaluations included an assessment of antibody activity by indirect immunohistochemistry on sectioned rhesus monkey eye, and Western blot reactions upon an extract of pig retina. Results:, Fundus ophthalmoscopy and fluorescein angiography revealed retinal vessel attenuation and retinal pigment epithelium degeneration. Electroretinogram suggested both rod and cone dysfunction. Indirect immunohistochemistry identified antibody activity within the photoreceptor outer segments. Western blots on the retina revealed that most of the patient's antibody activity was focused upon a retinal protein antigen approximating 145 kD. These findings share the commonalities of size and retinal distribution of the interphotoreceptor retinoid-binding protein (IRBP), a recognized autoantigen. The surgically resected mediastinal tumour was diagnosed as invasive thymoma. No other malignancy has since been found throughout nearly 10 years of follow-up. In March 2006, the patient developed a subfoveal CNV in his left eye, which was treated by PDT. Conclusion:, We describe the third case of paraneoplastic retinopathy associated with invasive thymoma. This is the first example of CAR involving autoantibodies reactive with a retinal protein having the characteristics of the IRBP, and is also the first complicated by CNV treated by PDT. [source] Oxidative damage is a potential cause of cone cell death in retinitis pigmentosaJOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2005JiKui Shen Retinitis pigmentosa (RP) is a prevalent cause of blindness caused by a large number of different mutations in many different genes. The mutations result in rod photoreceptor cell death, but it is unknown why cones die. In this study, we tested the hypothesis that cones die from oxidative damage by performing immunohistochemical staining for biomarkers of oxidative damage in a transgenic pig model of RP. The presence of acrolein- and 4-hydroxynonenal-adducts on proteins is a specific indicator that lipid peroxidation has occurred, and there was strong immunofluorescent staining for both in cone inner segments (IS) of two 10-month-old transgenic pigs in which almost all rods had died, compared to faint staining in two 10-month-old control pig retinas. In 22- and 24-month-old transgenic pigs in which all rods and many cones had died, staining was strong in cone axons and some cell bodies as well as IS indicating progression in oxidative damage between 10 and 22 months. Biomarkers for oxidative damage to proteins and DNA also showed progressive oxidative damage to those macromolecules in cones during the course of RP. These data support the hypothesis that the death of rods results in decreased oxygen consumption and hyperoxia in the outer retina resulting in gradual cone cell death from oxidative damage. This hypothesis has important therapeutic implications and deserves rapid evaluation. © 2005 Wiley-Liss, Inc. [source] | ||||||||||