Dissertations / Theses on the topic 'Retina'
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1
Ivert, Lena. "Interactions between neural retina, retinal epithelium and choroid /." Stockholm : Section of ophthalmology and vision, Department of clinical neuroscience, Karolinska institutet, 2006. http://diss.kib.ki.se/2006/91-7140-797-9/.
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Wu, Kathy H. "Histopathological studies of the aging human retina." Thesis, The University of Sydney, 2002. https://hdl.handle.net/2123/27837.
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Age-related macular degeneration (AMD) is the leading cause of untreatable blindness. Its global prevalence continues to increase in relation to aging of the population. Despite the increasing impact of AMD, its pathogenesis remains to be fully defined. Improved therapeutic measures such as photodynamic therapy and pharmacological interventions are being
developed for some cases of Wet AMD; however, treatment remains unavailable for the Dry form which accounts for a significant proportion of AMD cases. Neither has any intervention been developed to reduce the incidence of the disease.
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Larsson, Jörgen. "Central retinal vein occlusion certain risk factors, electroretinography and an experimental treatment model /." Lund : Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/68945007.html.
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West, Heloise Joan. "Control of retinal astrocyte numbers during development of the retina." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405230.
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Cox, Orla T. "Vascular cell death in diabetic retinopathy." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343079.
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Усенко, Наталія Миколаївна, Наталия Николаевна Усенко, Nataliia Mykolaivna Usenko, and T. S. Starostenko. "Artificial retina." Thesis, Вид-во СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/22108.
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Mellough, Carla Bernadette. "An assessment of the cell replacement capability of immortalised, clonal and primary neural tissues following their intravitreal transplantation into rodent models of selective retinal ganglion cell depletion." University of Western Australia. School of Anatomy and Human Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0101.
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[Truncated abstract] Microenvironmental changes associated with apoptotic neural degeneration may instruct a proportion of newly transplanted donor cells to differentiate towards the fate of the deteriorating host cellular phenotype. In the work described in this thesis, this hypothesis was tested by inducing apoptotic retinal ganglion cell (RGC) death in neonatal and adult rats and mice, and then examining whether intravitreally grafted cells from a range of sources of donor neural tissue became incorporated into these selectively depleted retinae. Donor tissues were: a postnatal murine cerebellar-derived immortalised neural precursor cell line (C17.2); an adult rat hippocampal-derived clonal stem-like line (HCN/GFP); mouse embryonic day 14 (E14) primary dissociated retinal cells (Gt[ROSA]26); and adult mouse ciliary pigmented margin-derived primary neurospheres (Gt[ROSA]26). In neonates, rapid RGC death was induced by removal of the contralateral superior colliculus (SC), and in adults, delayed RGC death was induced by unilateral optic nerve (ON) transection. Some adult hosts received ON transection coupled with an autologous peripheral nerve (PN) graft. Donor cells were injected intravitreally 6-48 h after SC ablation (neonates) or 0, 5, 7 or 14 days after ON injury (adults). Cells were also injected into non-RGC depleted neonatal and adult retinae. At 4 or 8 weeks, transplanted cells were identified, quantified and their differentiation fate within host retinae was assessed. Transplanted male C17.2 cells were identified in host retinae using a Y-chromosome marker and in situ hybridisation, or by their expression of the lacZ reporter gene product Escherichia coli beta-galactosidase (beta-gal) using Xgal histochemistry or a beta-gal antibody. No C17.2 cells were identified in axotomised adult-injected eyes undergoing delayed RGC apoptosis (n = 16). Donor cells were, however, stably integrated within the retina in 29% (15/55) of mice that received C17.2 cell injections 24 h after neonatal SC ablation; 6-31% of surviving cells were found in the RGC layer (GCL). These NSC-like cells were also present in intact retinae, but on average there were fewer cells in GCL. In SC-ablated mice, most grafted cells did not express retinal-specific markers, although occasional donor cells in the GCL were immunopositive for beta-III tubulin (TUJ1), a protein highly iii expressed by, but not specific to, developing RGCs. Targeted rapid RGC depletion thus increased C17.2 cell incorporation into the GCL, but grafted C17.2 cells did not appear to differentiate into an RGC phenotype.
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Allende, Marie Alexandra. "Blood vessel growth in primate retinal development relationship of retinal maturation with choriocapillaris growth and a role for TGF-ß in the retina /." Connect to full text, 2008. http://hdl.handle.net/2123/4145.
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Thesis (Ph. D.)--University of Sydney, 2008.Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Department of Clinical Ophthalmology and Eye Health, Faculty of Medicine. Title from title screen (viewed Apr. 8, 2009) Includes bibliography. Also available in print form.
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Whiteley, Simon J. O. "Deterioration and repair of visual function in the Royal College of Surgeons rat." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.344049.
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Leonelli, Mauro. "Receptores vanilóides TRPV1 na retina." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/42/42137/tde-22072011-131242/.
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A expressão do receptor de potencial receptor transiente, vanilóide 1 (TRPV1) começa desde estágios pré-sinaptogênicos da retina. O bloqueio farmacológico desse receptor nesse período diminui a apoptose fisiológica, havendo possível envolvimento da sinalização de MAP quinases. Na retina do animal adulto, observamos que a expressão de TRPV1 é amplamente difundida, albergando neurônios, células endoteliais e células da microglia. A ativação dos receptores TRPV1 é potencialmente citotóxica, e os mecanismos que podem estar envolvidos incluem a liberação de glutamato, a excitotoxicidade e o estresse nitrosativo. Evidenciamos que a lesão prévia de células ganglionares sensibiliza o tecido retiniano à citotoxicidade mediada pela estimulação de TRPV1. Porém, o bloqueio de TRPV1, tanto in vivo quanto in vitro, não inibiu a morte de células ganglionares axotomizadas. Esses dados sugerem que o receptor TRPV1 participa da modulação de diversos processos fisiopatológicos na retina.TRPV1 expression in the developing retina begins before retinal sinaptogenesis. TRPV1 blockade reduced the normal apoptosis in this period, and MAPK signaling seems to be involved in this process. In the adult retina, TRPV1 are expressed in neuronal, endothelial and microglial cells. The activation of those receptors is potentially cytotoxic, and glutamate release and further excitotoxicity and nitrosative stress might be also involved. Axotomized retinal ganglion cells were sensitized to TRPV1 citotoxicity, but TRPV1 antagonism, both in vitro and in vivo, did not reduce the loss of ganglion cell after axotomy. Our results suggest that TRPV1 receptors are involved in synaptic function and homeostatic control in the retina. Moreover, TRPV1 seems to be indirectly involved in cellular degeneration that follows the section of retinal ganglion cell axons.
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Källmark, Fredrik. "Investigations of perimetry and gaze-stability in the healthy and deceased retina /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-561-5/.
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Wolsley, Clive. "Structure-function studies of the retina using retinal imaging and multifocal electroretinography." Thesis, University of Ulster, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554273.
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In recent years there has been a great deal of interest in describing the relationships between the structure and function of the retina at a local level. Techniques such as the multifocal electroretinogram (mfERG) provide objective measures of localised retinal function and could provide new information about structure- function comparisons. Novel studies relating mfERGs with eo-localised structure and subjective function information have been undertaken in two ocular conditions, myopia and retinitis pigmentosa (RP). Measurements include peripheral resolution acuity, retinal thickness from optical coherence tomography (OCT), cone counts from confocal scanning laser ophthalmoscopy (CSLO) and ocular length at different eccentricities. In myopia where there is axial elongation of the eye, co-localised loss of mfERG function and reduced retinal cell density occur in regions where retinal laminar structure is thinned. This relationship is more evident in the peripheral retina rather than the central retina. In RP, where chronic deformation of the retina is likely, thinning of the photoreceptor layer and thickening of the inner retinal layers occurs. Only in some regions of the retina are these changes associated with a localised loss of retinal function. Preliminary data from images of the photoreceptor mosaic using CSLO suggests a strong correlation between co-localised cone counts and mfERG amplitude. These studies demonstrate a close association between changes in structure and function in myopia due to retinal stretching, but also suggest important underlying differences in myopic cell function. The structure- function relationship in RP is not always linear, but is dependent on retinal location and the precise nature of the measurements used. Empirical measures of cone density from retinal images could enhance evaluation of retinal structures in myopia and RP. Combining complementary measurements from ocular imaging and psychophysics with mfERG amplitude and timing demonstrates great potential for evaluating local retinal structure-function and function-function relationships in different eye conditions.
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Icha, Jaroslav. "Ganglion cell translocation across the retina and its importance for retinal lamination." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-218914.
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Correct layering (lamination) of neurons in the central nervous system (CNS) is critical for the tissue functionality. Neuronal lamination is established during development, when the majority of neurons have to move from their birthplace to the appropriate layer, where they function. Therefore, to grasp the logic of CNS development, it is essential to understand the kinetics and modes of the variety of neuronal translocation events. Most of our knowledge about neuronal translocation has been gained using fixed tissue or ex vivo imaging, which is not ideal for such a dynamic process heavily dependent on the surrounding environment. To avoid these limitations, I combined translucent zebrafish embryos with light sheet fluorescence microscopy, which together enabled gentle in toto imaging of neuronal translocation.
I studied the translocation of retinal ganglion cells (RGCs) across the developing zebrafish retina. RGCs are the first neurons that differentiate in the vertebrate retina and are born in a proliferative zone at the retinal apical side. From here, they move basally, spanning the complete apico-basal length of the tissue. They are destined to occupy the most basal layer, where their axons form the optic nerve. Although it was described that RGCs move their soma while being attached to both apical and basal sides of the retina, the kinetics and cell biological mechanisms of somal translocation remained unknown.
Extracting single cell behavior of RGCs from high-resolution movies of their translocation allowed for quantitative analysis of RGC movement. I revealed that RGCs cross the retina in less than two hours in a directionally persistent manner. The movement of RGC soma is a cell autonomously generated process, which requires intact microtubules and actin-dependent basal attachment of cells for speed and efficiency. Unexpectedly, interference with somal translocation leads to a shift towards a multipolar migratory mode, previously not observed for RGCs, in which they temporarily lose both apical and basal attachment and apico-basal polarity. The multipolar mode is overall slower and less directionally persistent, but still allows RGCs to reach the basal retina. However, when RGC translocation is inhibited completely, they differentiate ectopically in the center of the retina, which in turn triggers the formation of ectopic layers of later born neurons. These results highlight the importance of establishing the basal layer of ganglion cells for ensuing retinal lamination. Overall, I generated important advances in the understanding of neuronal translocation and lamination, which might be relevant for other parts of the CNS.
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Liber, André Maurício Passos. "Análise de células bipolares PKCa-IR e células ganglionares da retina do peixe tropical Hoplias malabaricus intoxicado com baixas doses agudas de metilmercúrio." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-04112011-120653/.
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O presente trabalho tem por objetivo analisar o efeito do metilmercúrio na retina de peixe tropical Hoplias malabaricus (Traíra) através de baixas doses agudas. As intoxicações foram realizadas, por meio de injeção intraperitoneal, nas doses de 0,01, 0,05, 0,1 e 1,0 g/g, com um período de quinze dias de depuração do MeHg. Após o término do período de depuração, os olhos foram enucleados e as retinas isoladas foram fixadas em PFA 4% por 3 horas. As retinas foram conservadas, até o momento do uso (ou por no mínimo 9 horas), em tampão PB 0,1M a 4ºC. Após os procedimentos imunohistoquímicos para marcação de células bipolares do tipo ON com estratificação na sublâmina b da CPI, as retinas foram aplanadas para confecção de montagens planas para a análise quantitativa de células bipolares ON imunorreativas a proteína cinase C _. A análise quantitativa das células da camada de células ganglionares (CCG) também foi realizada. Células da CCG foram coradas pela técnica de Nissl, as retinas foram aplanadas em lâminas gelatinizadas e submetidas a uma bateria de desidratação (com diferentes concentrações alcoólicas) e coloração, utilizando cresil violeta como corante. Estas análises foram realizadas em 3 ou 4 retinas para cada dose testada. Análises idênticas foram realizadas nas retinas controle. Todas as retinas foram dividas nos quadrantes dorsal, ventral, nasal, temporal e em centro e periferia. Campos foram fotografados por toda a retina com intervalos de 1 mm, com auxilio do programa Axio Vision por meio de uma câmera digital e um microscópio acoplados a um computador. Os campos amostrados foram contados com o auxilio do programa NIH Scion Imagem 2.0. A densidade média de células foi estimada para cada retina e os grupos intoxicados foram comparados com o grupo controle (Teste T-student). A partir dos dados de densidade celular, mapas de isodensidade foram confeccionados, além de permitir estimar o poder de resolução teórico da acuidade visual de cada um dos animais experimentais utilizados para análise de células da CCG a partir da densidade máxima de células. Evidenciamos que as baixas doses agudas testadas não causam diminuição na densidade célular de células bipolares ON e células da CCG, comparado ao grupo controle. Não houve reduções significativas na densidade de células para ambos os tipos celulares analizados em nenhuma das regiões retinianas nas doses de MeHg testadas. Assim, a intoxicação de MeHg por baixas doses agudas não alterou o poder de resolução teorio da acuiade visual dos animais testadosThis study aims to examine the effects of low acute doses of methylmercury (MeHg) on the retina of the tropical fish Hoplias malabaricus (Thraira). Four levels of MeHg intoxication were induced by intraperitoneal injection of doses of either 0.01, 0.05, 0.1 or 1.0 g MeHg/g of body weight, followed by a fifteen day period of depuration of MeHg. After the depuration period, the eyes were harvested, and the retinas were isolated and fixed in 4% paraformaldehyde for 3 hours. The retinas were then stored (for at least for 9 hours) in 0.1 M sodium phosphate PB buffer at 4°C until the time of analysis. ON bipolar cells in sublamina b of the inner plexiform layer immunoreactive to protein Kinase C_ were immunohistochemically labeled, and the retinas were flattened to make whole mounts for quantitative analysis of ON bipolar cell densities. Quantitative analysis of cells in the retinal ganglion cell layer (GCL) was also performed. GCL cells were Nissl stained, and the retinas were flattened on gelatinized slides and subjected to another battery of dehydration (with different alcohol concentrations) and staining using cresyl violet. These analyses were carried out in 3 or 4 retinas for each dose tested. Identical analyses were performed on the control retinas. All retinas were divided into regions: dorsal, ventral, nasal, temporal, center and periphery. Sample retinal fields were photographed throughout the retina at intervals of 1 mm, with a digital camera attached to a microscope using Axio Vision software coupled to a computer. ON bipolar and GCL cells within the fields were counted with the help of the NIH Scion Image 2.0 software. The average density (mm2) of both types of cells was estimated for each retina and the data from each of the four MeHgintoxicated groups were compared with the control group values (Student t-test). From the density data we derived isodensity maps, permitting us to estimate the theoretical resolving power (maximum visual acuity) of each of the experimental animals used from the maximum density of cells in the ganglion cell layer. We showed that low acute doses of MeHg/g do not decrease cell densities of either ON bipolar cells or cells in the GCL, compared to controls. There were no significant decreases in cell density (counts) for either cell type in any of the retinal regions, for any of the MeHg doses tested. Thus, acute low-dose MeHg intoxication did not degrade the estimates of the animals theoretical resolving power
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van, Wyk Michiel. "Local edge detectors in the rabbit retina /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19350.pdf.
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Chang, Hui. "Oxidative stress in the retina an experimental study in the rat /." Lund : Dept. of Ophthalmology, University Hospital, Lund University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39725792.html.
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Balen, Fernanda. "Em busca de novos métodos de tratamento para a retinose pigmentar causada por mutações na rodopsina." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/42/42134/tde-13112012-092432/.
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Retinose Pigmentar (RP) é uma doença hereditária que conduz progressivamente à cegueira. Mais de 150 mutações da rodopsina associadas à RP foram descritas, e causam a alteração da sua conformação. Esta tese testou a hipótese de que pequenas moléculas auxiliam na formação da rodopsina e/ou reduzem a morte dos fotorreceptores. As mutações da RP, N15S e P23H, revelaram diferenças quanto às características e gravidade devido à má-formação das proteínas mutantes. Ligação de pequenas moléculas (retinóides, íons metálicos, clorofilas e antocianinas) à rodopsina foi demonstrada in vitro. O derivado da clorofila, Ce6, mostrou-se mais efetivo, conferindo maior estabilidade e foi então testado em ratos submetidos à degeneração por luz ou em modelos de RP (P23H e S334ter). Observou-se uma proteção contra a degeneração por luz e uma significante diminuição da degeneração no P23H. Em contraste, Ce6 causou um aumento na degeneração dos fotorreceptores do S334ter. Finalmente, resultados clínicos, bioquímicos e in vivo foram comparados e mostraram estar altamente relacionados.Retinitis Pigmentosa (RP) is an inherited disease that progressively leads to blindness. More than 150 mutations associated with RP are known in rhodopsin, causing its misfolding. This thesis tested the hypothesis that small molecules can rescue folded rhodopsin and/or reduce photoreceptor cell death. RP mutations, N15S and P23H, revealed differences in characteristics and severity of misfolding of the mutant proteins. Binding of small molecule classes (retinals, metal ions, chlorophylls and anthocyanins) to rhodopsin was demonstrated in vitro. The chlorophyll derivative, Ce6, was most effective in conferring stability and therefore tested in rats subjected to light-damage and RP rat models, P23H and S334ter. Protection against the light-induced retinal degeneration and more importantly a significant slowing of the photoreceptor degeneration rate in the P23H rat were observed. In contrast, Ce6 increased photoreceptor degeneration in the S334ter rat. Finally, clinical, biochemical and in vivo rat data were compared and it was found to be highly correlated.
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Martinez-De, Luna Reyna I. "Regulation and Function of the Retinal Homeobox (Rx) Gene in the Developing and Regenerating Retina of Pre-Metamorphic X. laevis." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253198225.
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Xue, Xiaoyan. "Identification of retinal stem cells in the ciliary marginal zone of the Xenopus retina." Thesis, University of Cambridge, 2010. https://www.repository.cam.ac.uk/handle/1810/283870.
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Ozaki, Shiro. "Influence of the sensory retina on healing of the rabbit retinal pigment epithelium." Kyoto University, 1997. http://hdl.handle.net/2433/202179.
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Walsh, Natalie. "Environmental and genetic influences affecting photoreceptor survival and stability in the mammalian retina." Thesis, The University of Sydney, 2003. https://hdl.handle.net/2123/27873.
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The aims of this thesis were to investigate the stability of the light receptive visual cell - the
photoreceptor — in the face of environmental and genetic insults. Naturally occurring inherited mouse
retinal degenerations, and an engineered transgenic retinal degeneration in the rat, were used as
models of genetic stress. Light, oxygen and the naturally occurring ‘edge-stress’ of normal retina,
were used as models of environmental stress. Through the use of cell death markers and probes to
trace protein and gene expression patterns, the innate responses of the retina were investigated within
the context of retinal degeneration. In addition, the functional status of the retina was assessed using
electrophysiological techniques, the results of which were related to the structural and
immunocytochemical analysis.
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Lopes, Maria Inês Valadinha Mendes. "Oclusão venosa da retina." Master's thesis, Universidade da Beira Interior, 2013. http://hdl.handle.net/10400.6/1502.
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A oclusão da veia central da retina é uma patologia ocular que provoca bloqueio da circulação sanguínea retiniana causada por obstrução da veia central da retina ou, consequentemente, dos seus ramos. Esta, subdivide-se em: isquémica ou não-isquémica, dependendo do grau de oclusão da veia, sendo a primeira a mais alarmante. A oclusão pode ocorrer em torno de toda a área vascularizada da retina, desde a artéria central da retina á veia central da retina, sendo que a localização da oclusão permite enquadrar esta patologia num quadro clínico específico e característico.
Esta patologia é muito característica de determinadas doenças pré-existentes que proporcionam o desenvolvimento de alterações vasculares. Quando as doenças interagem com a organização celular das estruturas das veias e artérias podem provocar o rompimento desta barreira e levar ao derrame dos líquidos internos. Esses líquidos ao serem absorvidos pelos tecidos em redor provocam um inchaço dessas camadas evoluindo para um edema generalizado com lesões permanentes.
A perda repentina de visão unilateral é o principal sintoma que o paciente apresenta, e assim que detetada essa falta o paciente deve dirigir-se ou ser reencaminhado para um oftalmologista com caracter de urgência. É importante salientar que nem sempre esta perda é reversível, tal como nem sempre a sua melhora de visão é significativa. Esta patologia apresenta sempre um prognóstico muito reservado. O fator tempo é determinante para que o paciente tenha melhoria de visão nos períodos seguintes, ou seja quanto mais rápido for realizado o tratamento mais eficaz poderá ser.The central retinal vein occlusion is an eye disease that blocs the bloodstream caused by an obstruction of the retinal central vein or of its ramifications. This disease can be classified as schematic or non-schematic, being the first one more dangerous. The occlusion may occur around the entire vascularized area of the retina from the central retinal artery to the central vein of the retina. The location of the occlusion allows you to consider this pathology in a very specific clinical status. This condition is very characteristic of certain pre-existing pathologies which provide the development of vascular disorders. When those diseases interact with the cellular organization structures of the arteries and veins, they can promote the disruption of this barrier and lead to leakage of internal fluids. The majority of these liquids are absorbed by the tissues around and consequently they cause a swelling of the adjacent layers. That can evolute to a generalized edema with permanent injuries. The sudden loss of unilateral vision is the main symptom that the patient detects. Immediately after this occurrence the patient must go or be redirected to an ophthalmologist with a matter of urgency. It is important to know that this loss is not always reversible and the lost visual acuity may not be significantly recovered after treatment. This disease has always had a very limited prognosis. Time is the main and crucial factor for the patient, when it comes to improve vision in the following periods. The sooner the treatment is performed, the more effective it will be.
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Znamenshchykov, Y., and D. O. Marchenko. "The artificial retina project." Thesis, Видавництво СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/17585.
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Pascual, Rodríguez Beatriz. "Anàlisi de variants genètiques mitjançant NGS en pacients amb distròfies de retina. Transcriptoma (RNAseq) diferencial de cèl·lules de retina (RPE) induïdes in vitro amb mutació en el factor de splicing PRPF8." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/664226.
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Les distròfies de retina (DR) són un grup malalties rares que provoquen una degeneració dels fotoreceptors i posterior pèrdua de visió; dins de les quals, la Retinosis Pigmentària (RP) és la majoritària. Són malalties amb gran heterogeneïtat genètica i les mutacions associades es troben tan a gens específics de retina, com a gens d’expressió ubiqua, com són els factors de splicing o PRPFs, que causen formes de RP autosòmica dominant (adRP).
Gràcies a les tècniques de seqüenciació massiva (NGS), s’ha dissenyat un panell propi de 107 gens associats a DR. La validació del panell i utilització de forma rutinària al laboratori, ha permès el diagnòstic molecular de les DR en pacients. Per a la recerca i caracterització de nous gens candidats a ser responsables de adRP en famílies que no es van resoldre mitjançant el panell de DR, es va utilitzar la tècnica de Whole Exome Sequence (WES). Mitjançant WES es va resoldre una de les 4 famílies en estudi.
S’han obtingut cèl·lules iPSCs derivades de fibroblasts dèrmics d’un pacient adRP amb mutació en el factor de splicing PRPF8. Aquestes cèl·lules s’han pogut diferenciar a cèl·lules d’endoteli pigmentari retinià (RPE), permetent així la obtenció d’un model cel·lular in vitro per poder estudiar els mecanismes moleculars que provoquen la malaltia. Mitjançant la tecnologia RNA.seq, s’ha pogut observar per primera vegada, diferències significatives en l’expressió de gens e isoformes (especialment amb retenció d’introns) en cèl·lules específiques de retina (RPE) amb PRPF8 mutat. Aquestes diferències no es van observar en altres tipus cel·lulars, com fibroblasts dèrmics; de manera que es mostra per primera vegada, un mecanisme molecular diferencial en cèl·lules de retina, induït per una mutació en el factor de splicing PRPF8, que podria ser la causa de la patologia (adRP) que es produeix únicament en retina.Retinal dystrophies (RD) are a group of rare diseases that cause photoreceptor degeneration and subsequent loss of vision; in which Retinitis pigmentosa is the most common. These diseases are genetically heterogeneous, with mutations associated in specific retinal genes, but also in ubiquitous expression genes, like PRPF splicing factors, that cause autosomal dominant retinitis pigmentosa (adRP). A panel of 107 genes associated with RD was designed for the molecular diagnosis of DR by next generation sequencing (NGS). This panel was validated and is used in the routine of the laboratory. The Whole Exome Sequence (WES) technique was used in order to characterise new candidate genes to be responsible of adRP in families that were not resolved through the DR panel. By WES one of the four analysed families was resolved. Induced Pluripotent Stem Cells (iPSCs) were obtained from skin fibroblasts of an adRP patient with a mutation in the PRPF8 splicing factor. These cells were differentiated into retinal pigment epithelium (RPE) cells, allowing to generate an in vitro cellular model to study the molecular mechanism that cause the disease. Using RNA.seq technology, it has been possible to observe for the first time significant differences in the expression of genes and isoforms (especially intron retention forms) in specific retinal cells (RPE) with mutated PRPF8. These differences were not observed in other cell types, such as skin fibroblasts. For the first time, a differential molecular mechanism induced by a mutation in the PRPF8, is shown in retinal cells. This mechanism could be related to the development of adRP in the patient.
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Dunn, Felice Audris. "Gain control of rod and cone vision in the mammalian retina /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10642.
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Landi, Silvia. "Plasticity of the mammalian retina during development." Doctoral thesis, Scuola Normale Superiore, 2006. http://hdl.handle.net/11384/85962.
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Davenport, Christopher M. "Neural circuitry of retinal receptive fields in primate /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10652.
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Bhagavatheeshwaran, Govind. "Magnetic Resonance Imaging of the Rat Retina." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-041608-144837/.
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Thesis (Ph.D.)--Worcester Polytechnic Institute.Keywords: Mn54-autoradiography, rat retina, manganese enchanced mri, rcs rat, magnetic resonance imaging, retinal degeneration, high-resolution mri, blood volume imaging Includes bibliographical references (leaves 211-226).
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Paschon, Vera. "Bloqueio do acoplamento celular após trauma mecânico na retina altera a distribuição de células em apoptose." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/42/42137/tde-18062014-141212/.
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A neuroproteção é um dos tópicos mais relevantes aplicados à neurociência. As junções comunicantes (JC), formadas pelas conexinas (Cx) estão envolvidas na neurodegeneração após lesão. Estudos com animais KO apresentam resultados contraditórios sobre papel das JCs. O objetivo deste trabalho foi analisar o papel das Cxs a partir do trauma mecânico na retina, modelo que permite a visualização do foco, penumbra, e áreas adjacentes à lesão. Observamos regulação distinta das Cx36 e Cx43 durante a neurodegeneração. A Cx36 não se alterou e a Cx43 apresentou desorganização e aumento da imunorreatividade após 7 dias, concomitantemente com GFAP. Células amácrinas apoptóticas encontram-se acopladas a células vizinhas por Cx36. O papel funcional das JCs foi avaliado, utilizando bloqueadores, para verificar a viabilidade/morte de células. Carbenoxolone (CBX), reduziu o espalhamento da apoptose, após 4h, enquanto a quinina, teve o mesmo efeito após 1h. A distribuição de núcleos apoptóticos confirmou que a utilização de bloqueadores de JCs reduz a propagação da apoptose. A quinina, mas não o CBX, diminuiu a expressão de caspases iniciais e efetoras. O controle da permeabilidade de canais de JCs pode participar de estratégias de neuroproteção.The neuroprotection stands out as one of the most pursued hot topics in applied neurosciences. The gap junctions (GJ), formed by connexin (Cx) are involved in neurodegeneration injury. Studies using KO animal models endowed apparently contradictory results in relation to the role of coupling in neuroprotection. The aim of this study was to analyze the role of Cx-mediated communication in focal lesion induced by mechanical trauma in the retina, a model that alow the visualization of the focus, penumbra and adjacent areas. We observed distinct regulation of Cx36 and Cx43 during neurodegeneration. The Cx36 did not change during the lesion progression and Cx43 showed disorganized pattern and upregulated after 7 days, the same as GFAP. Apoptotic amacrine cells are coupled with health neighborhood cells by Cx36. The functional role of GJ was evaluated using blockers to verify the viability/cell death. Carbenoxolone (CBX) reduced the spread of apoptosis after 4h while quinine had the same effect after 1h. The distribution of apoptotic nuclei confirmed that the use of GJ blockers reduced the propagation of apoptosis. Quinine, but not CBX, decreases initial and effector caspases expression. The control of GJ channels permeability can participate in neuroprotection strategies.
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Lin, Xiaohui. "Modulation of retinal ganglion cell responses by the endocannabinoid system and the involvement of TRPV1 channels." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18946.
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The endocannabinoid (eCB) system was found to modulate synaptic transmission in the central nervous system (CNS). The retina carries out complex neural computations that involve several physiological mechanisms, including short and long-term plasticity phenomena. The mechanisms responsible for modifying the strength of retinal synaptic transmission, however, are not fully understood. Previous studies in the Vision Lab showed that bath application of a drug that elevates the concentration of endocannabinoids reduced the peak amplitude of visual-evoked postsynaptic potentials (vePSP) in retinal ganglion cells (RGCs) but paradoxically increased their spiking output. In addition, the rise in endocannabinoid concentration shifted the voltage dependence of the sodium current to the left. The reduction in vePSP amplitude is consistent with the known presynaptic effects of eCBs on synaptic transmission whilst it was postulated that the increase in spiking output could be mediated by TRPV1 receptors, which are nonselective ligand gated cation channel sensitive to eCBs and a broad range of other stimuli. This study investigated the potential role of TRPV1 channels in the modulation of RGCs excitability by recording their electrical activity in wild-type and TRPV1 knock-out mice using whole cell patch clamping techniques. We found that the endocannabinoid anandamide acts on TRPV1 channels to increase cell excitability. Increasing the levels of anandamide in the absence of TRPV1 channels, however, led to the activation of RGCs at more hyperpolarised potentials, suggesting that other targets of anandamide are involved in RGC modulation. Moreover, the TRPV1 agonist and antagonist capsaicin and capsazepine are likely to have non-specific effects as application of capsazepine was able to reduce cell excitability in the TRPV knockout mice (TRPV1-/-).
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Hauck, Stefanie. "Neuroprotective pathways in the retina." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-45535.
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Mendl, Christian. "Neuronal coding in the retina." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-139015.
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Zhou, Yun. "Reconfigurable Terahertz Integrated Architecture (RETINA)." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509509.
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Spencer, Timothy. "Digital imaging of the retina." Thesis, University of Aberdeen, 1992. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=124209.
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In this study, fluorescein angiograms of the ocular fundus have been digitised to enable them to be processed and analysed by computer. A fully automated technique for counting microaneurysms (MA) in these images was developed with a view to producing an objective, accurate and highly repeatable way of quantifying these lesions. Prior to any other image processing, a number of pre-processing stages were applied in order to compensate for non-uniformaties and to remove the background fluorescence component present in all the images. Matched filters modelled on two-dimensional Gaussian distributions were employed to detect MA in the 'shade-corrected' images. A binary image representation of the vascular network was constructed. This 'vessel mask', used in conjunction with the original match-filtered images, enabled MA to be detected by grey-level thresholding the filtered images. The resulting binary objects could then be counted by the computer as MA. The automated technique was assessed by comparing the computer's results for six fluorescein angiograms with MA counts obtained by ophthalmologists analysing both analogue and digital images. The performance of both man and machine were judged with respect to 'gold standards' compiled from prints of the original negatives. The best results were obtained by the clinicians analysing the analogue prints, although they differed greatly in their ability to detect microaneurysms. The computer performed better than the clinicians when they were counting MA in the digital images and produced highly repeatable results. To improve the performance of the automated technique, images were captured at approximately four times the previous spatial resolution and a smaller area of each image was analysed. Additionally, more complex image-processing techniques were employed to increase the accuracy of the computer analysis. Although the performance of the automated technique was improved, the computer results only matched those of the clinicians' analogue analyses for two of the images.
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Dent, C. L. "cDNA cloning and the retina." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384395.
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Hiscox, Rachel Joy. "The retina in cystic fibrosis." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/59738/.
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Cystic fibrosis (CF) is caused by defective function of CF Transmembrane Conductance Regulator (CFTR), an epithelial ion channel that facilitates chloride secretion. Previous research has identified impaired dark adaptation (DA) in CF, which has been attributed to concomitant vitamin A deficiency or CF-related diabetes (CFRD). However, CFTR has been localised to the retinal pigment epithelium (RPE) and it is proposed that abnormal DA could be a primary manifestation of CF. DA is similarly impaired in individuals with type 1 and 2 diabetes and is thought to be caused by retinal hypoxia as oxygen inhalation ameliorates abnormal thresholds. The aim of this thesis was to investigate DA during oxygen inhalation in CF subjects with and without CFRD to gain further insight about the aetiology of this abnormal DA. The work also aimed to examine retinal structure using optical coherence tomography (OCT) to determine the consequences of CFTR dysfunction at the RPE. Final DA thresholds were not impaired in CF subjects as a whole during the inhalation of air. However, when grouped according to diabetic status, CFRD subjects showed a significantly elevated final rod threshold which was ameliorated following oxygen inhalation. This suggests that the retina is hypoxic in CFRD subjects and that impaired DA in CF is secondary to CFRD rather than a primary manifestation of CFTR malfunction at the RPE. Contrary to the proposed hypothesis, retinal and RPE/photoreceptor layer thickness was significantly thinner in CF subjects. These results suggest that impaired CFTR function at the RPE does not directly affect retinal structure. · In conclusion, this is the first study to determine that retinal structural and functional abnormalities are not caused directly by CFTR dysfunction but are a secondary manifestation of the disease. Further research is necessary to understand the impact of these findings.
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Peixoto, Nathalia Lopes Vieira. "A depressão alastrante na retina." [s.n.], 1997. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259929.
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Orientador: Vera Maura Fernandes de LimaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-07-22T04:07:50Z (GMT). No. of bitstreams: 1 Peixoto_NathaliaLopesVieira_M.pdf: 6223894 bytes, checksum: 506f9bdf96ea612940ee80c59112b873 (MD5) Previous issue date: 1997
Resumo: Apresentamos neste trabalho um estudo sobre o fenômeno da depressão alastrante na retina in vitro de pintainho. O enfoque experimental investiga a relação espaço-temporal entre dois dos concomitantes das ondas de depressão alastrante: a alteração lenta de potencial e o sinal intrínseco óptico. Além disso, avalia-se o efeito de manipulações fármaco-químicas sobre estes dois concomitantes. Do ponto de vista teórico, propomos duas formas matemáticas diversas de interpretar a depressão alastrante, urna delas baseada na teoria de autômatos celulares e a outra em equações de reação-difusão. Implementamos dois modelos computacionais a partir destas interpretações, e discutimos sua aplicabilidade e seu poder de simulação do fenômeno biológico
Abstract: This work presents an investigation of the phenomenon of the spreading depression in the in vitro chicken retina. The experimental approach deals with the space-time relationship between two of the spreading depression wave concomitants: the slow shift potential and the intrinsic optical signal. Chemical manipulations on the perfusing solution are performed and their effect on the two concomitants analyzed. Under the theoretical point ofview, we propose two different mathematical interpretations to describe the spreading depression. One of them is based on the theory of cellular automata, and the other on the reaction-diffusion equations. We implement two computational models and discuss their applicability and their capacity to simulatethe biological phenomenon
Mestrado
Automação
Mestre em Engenharia Elétrica
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Zhu, Jie. "Mechanisms of Chick Retina Regeneration." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1378202459.
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Rojahn, Martin. "Encapsulation of a retina implant /." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10378693.
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Zamora, Brian G. "Functions of Rx in early vertebrate ocular development." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10830.
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Thesis (Ph. D.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains x, 148 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 136-148).
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Bergdahl, Sara. "Skillnaden i central och perifer retinal tjocklek mellan olika ametropier - en OCT-studie." Thesis, Linnéuniversitetet, Institutionen för medicin och optometri (MEO), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-26595.
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Syfte: Syftet med studien var att, med hjälp av Optical Coherence Tomography (OCT), undersöka om det finns någon skillnad i central och perifer retinal tjocklek mellan olika ametropier. Metod: Studien omfattade 36 försökspersoner, som grupperades beroende på ametropi i en myop, emmetrop och hyperop grupp. Av de 36 försökspersonerna var det 15 myoper, 15 emmetroper och 6 hyperoper. En inledande mätning gjordes där försökspersonernas objektiva refraktion uppmättes med autorefraktor och därefter gjordes en avstämning i provbåge för att säkerställa refraktionen. Med OPKO Spectral OCT/SLO mättes retinas tjocklek både centralt och perifert på höger öga. För att analysera resultatet delades retina in i 15 olika zoner som jämfördes mellan de olika ametropierna. Resultat: Resultatet av studien visade en signifikant skillnad i foveal tjocklek mellan de olika ametropierna (p=0,03). Det var en siginifikant skillnad i retinal tjocklek mellan retinas zoner i alla tre ametropier (p<0,01), dock var det ingen signifikant skillnad i perifer retinal tjocklek mellan de tre olika ametropierna (p=0.07). Slutsats: Ingen skillnad i central och perifer retinal tjocklek kunde redovisas mellan de olika ametropierna. Då en tidigare studie har visat att den retinala tjockleken skiljer sig mellan olika ametropier kan resultatet av vår studie diskuteras då det i vår studie fanns brister som få antal personer, olika antal personer inom grupperna och en låg utbredning av synfel.
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Gill, Helen Marah. "A theoretical three dimensional electromagnetic eye : advances towards the optimisation of electroretinographic signal recovery." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368752.
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Moshiri, Ala. "Sonic hedgehog in the vertebrate retina /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10669.
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Bumsted, Keely Maureen. "The role of opsin expression in the development of photoreceptor topography and synapses in the fetal primate retina /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/5679.
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Sorcha, Finnegan. "Proteomic and raman analysis of the developing wild type and retinal dysplasia and degeneration chick retina." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491884.
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The aim of this investigation was to initiate proteomic and Raman analysis of the wild type (wt) and retinal dysplasia and degeneration (rdd) chick retina. 20 protein profiles were generated for wt and rdd adult and embryonic chicken retina, immunohistochemical analysis was carried out for a number of proteins, and, Raman maps were constructed demonstrating the principal components in the wt, rdd, embryonic and post hatch chick retina. Initially differential solubilisation protocols were employed prior to 20 PAGE and subsequently, distinct protein profiles were generated for the different methods of extraction. 20 PAGE, image analysis and MS were used to analyse the developing retinal proteome from wt chick retina. A number of developmentally regulated proteins that may be intrinsic to the process of retinal maturation were identified and their expression plotted over the examined time frame. Proteomic analysis of the rdd retina identified seven proteins that were modulated during retinal degeneration and immunohistochemical analysis was employed to localise a number of proteins in the avian retina. This study provided the first holistic investigation of protein changes in the rdd chick retina and may enable focus to specific proteins and specific pathways that may play key roles in the initiation and progression of retinal degeneration. A parallel study employed Raman microscopy to investigate the distribution of the dominant biochemical species in the chick retina and detected and mapped the distribution of proteins, lipids, cytochrome, saccharide and DNA in the developing and degenerating retina. To conclude, this study of developing and degenerating chick retina was interfaced with the complex developmental and degenerative events in the rdd chick. Two interrelated research platforms, proteomics and Raman microscopy, were used to begin to define wt chick retinal biochemistry with that expressed in the developing and degenerating rdd chick retina.
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Sidaway, Peter. "P2X7 receptor signalling mechanisms underlying extracellular purine mediated retinal ganglion cell death in the human retina." Thesis, University of East Anglia, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522245.
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Jalligampala, Archana [Verfasser]. "Zapping the Retina - Understanding electrical responsiveness and electrical desensitization in mouse retinal ganglion cells / Archana Jalligampala." Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/121463978X/34.
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Sardo, Giacomo. "Caratteristiche morfologiche della retina nei Cetacei." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8130/.
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Le caratteristiche strutturali dell’occhio dei Cetacei sono state in passato oggetto di studio. Tuttavia, i dati relativi alla stratigrafia della retina ed alle caratteristiche morfologiche dei neuroni gangliari in essa presenti sono piuttosto ridotti; per questo motivo, l’obiettivo della presente ricerca è stato quello di studiare, mediante metodiche di immunoistochimica, l’uso della microscopia ottica e di opportuni software di analisi immagine, le caratteristiche morfologiche della retina e delle cellule gangliari in essa presenti in differenti specie di Cetacei.
Per la presente ricerca sono stati utilizzate come specie di riferimento i seguenti Delfinidi: tursiope (Tursiops truncatus) e stenella striata (Stenella coeruleoalba). Le analisi sulle sezioni interessano l’area, la densità dei neuroni gangliari, la stratigrafia della retina e l’analisi morfometrica degli strati e dei neuroni.
I risultati ottenuti indicano come la retina del tursiope e della stenella striata, nonostante un'organizzazione di base assai simile a quella degli altri Mammiferi, mostri caratteristiche qualitative sue proprie. Gli strati retinici sono quelli che si osservano in tutti i Mammiferi e lo spessore totale della retina è, nel tursiope (101,23 µm ) e nella stenella striata (108.35 µm ), pressochè simile ai Mammiferi terrestri (110-220 µm). Nell'ambito della retina, lo strato che presento lo spesso medio maggiore è quello dei granuli interni (SNE); tale dato non coincide con quanto osservato in altri Mammiferi. I neuroni gangliari presenti nella retina di tursiope e stenella striata mostrano, analogamente a quanto osservato in altri Cetacei, una bassa densità cellulare. Nel tursiope e nella stenella striata le aree a maggiore densità cellulare presentano neuroni multipolari di dimensioni minori rispetto a quelle con bassa densità. Questo dato potrebbe indicare una "cellularità" (quantità di superficie occupata da cellule) costante nei differenti distretti retinici.
I neuroni gangliari presenti nella retina di tursiope e stenella striata sono disposti in un unico strato, come osservato in numerosi altri Cetacei, ma differisce da quanto osservato nel capodoglio (Physeter macrocephalus) dove tali cellule si dispongono in strati multipli. Neuroni gangliari di grandi dimensioni sono stati osservati sia nel tursiope che nella stenella striata. Tale dato coincide con quanto osservato in altri Odontoceti ed in alcuni Misticeti.
Allo stato attuale non è ancora stato dato un chiaro significato funzionale alle cellule gangliari giganti. Un possibile ruolo potrebbe essere quello di condurre, in animali di grossa mole, l'impulso nervoso molto velocemente, grazie alla presenza di un assone provvisto di un diametro notevole. Tale interpretazione non è da tutti accettata in quanto Mammiferi terrestri di grandi dimensioni non presentano nella loro retina neuroni gangliari giganti.
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Franssen, Luuk Coppens Joris Eduard. "Straylight at the retina scattered papers /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/43594.
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Wilson, James George. "On the object detecting artificial retina." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366328.
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