Orientador: Vera Maura Fernandes de Lima / Dissertação (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

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 testados / This 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

Orientador: Keila Miriam Monteiro de Carvalho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-04T14:57:39Z (GMT). No. of bitstreams: 1 Torigoe_AndreaMaraSimoes_D.pdf: 720496 bytes, checksum: c94a4aae01f9b862038cbb0c3649b718 (MD5) Previous issue date: 2005 / Resumo: A retinopatia da prematuridade (RP) é uma das principais causas de cegueira e morbidade visual na infância. Doença vasoproliferativa desenvolve-se a partir da vascularização retiniana imatura e sua detecção precoce e tratamento no estágio limiar ¿ estadio 3, diminui as seqüelas cicatriciais da doença e reduz o risco de perda visual. Doença freqüente com predominância pelos estadios menos avançados e regressão espontânea. Este estudo foi proposto para analisar a incidência e principais características da RP na população de crianças prematuras nascidas no Centro de Atendimento Integral à Saúde da Mulher- Caism - Unicamp, no período de janeiro de 1999 a dezembro de 2003, com vistas ao melhor conhecimento desta afecção. Realizou-se estudo longitudinal prospectivo, descritivo e analítico em coorte de 337 crianças prematuras. Observou-se incidência da RP em qualquer estadio de 28,19%, sendo que 66,67% da RP ocorreram em crianças nascidas com 1000g ou inferior e predominância dos estadios mais precoces da RP. Observou-se 7,37% de incidência para o estadio 3 limiar, sendo esta a freqüência de tratamento por meio de crioterapia para a RP, proporcionando 100% de resolução da doença. O seguimento oftalmológico iniciou-se entre 4 a 6 semanas de idade cronológica (IC) ou 31 a 33 semanas de idade pós-concepção (IPC) e a maturação vascular da retina, em média, ocorreu com 22 semanas de IC, período no qual este seguimento mostrou-se recomendável. A reversão dos diversos estadios da RP para a maturação vascular iniciou-se em uma mesma época, completando-se mais tardiamente nos estadios mais avançados. O peso mostrou-se o fator de risco mais significativo para presença da retinopatia da prematuridade. Na ocorrência de hemorragia intraventricular, a RP foi observada com maior freqüência e mais precocemente, juntamente com baixo peso ao nascimento, idade gestacional e utilização de oxigênio no primeiro mês de vida, que representaram os principais fatores de risco relacionados à RP. Observou-se maior percentual de miopia e estrabismo, no primeiro ano de vida no grupo de crianças que desenvolveu a RP e necessitou tratamento. O exame oftalmológico deve iniciar-se entre 4 a 6 semanas de idade cronológica ou 31 a 33 semanas de idade pós-concepcional, sendo o período de risco para o desenvolvimento do estadio 3-limiar as primeiras 16 semanas de idade cronológica ou 62 semanas de idade pós-concepção, período mínimo de seguimento nas crianças com fatores de risco para RP. O conhecimento das características dessa doença permite a detecção precoce dos estadios da RP e a seleção do momento ideal para tratamento / Abstract: The Retinopathy of prematurity (ROP) is one of the main causes of visual impairment in children. ROP is a vascular proliferative disease that develops from a immature retinal vascularization and earlier diagnosis and treatment of threshold stages (stage 3) reduces the risk of visual loss. ROP has 5 stages of development that develop in the first 6 months of life. Until the second stage of illness, 80% of patients have spontaneous regression. The same not occur in higher stages. Prematurity, low weight at birth, and oxygen supplement are risk factors current established for the development of ROP. The etiology of ROP remains obscure, although several studies suggests been multifactorial. This study, pointed that the incidence of ROP in any stage is 28,19%, that 66,67% of ROP occurred in children born with 1000g or less and the majority of the earlier stages of ROP with spontaneous regression of ROP. 7,12% of incidence to the stage 3 threshold was submitted from cryotherapy , that lead to 100% of resolution of disease. The ophthalmologic examination started between 4 and 6 weeks of chronologic age or 31 and 33 weeks of post conception age. The vascular maturation of retina in average occurred with 22 weeks of chronologic age, period in which the accompaniment revealed recommendable. The changing of different stages of ROP to vascular maturation began in the same time, but completing more lately in the higher stages. The birth weight revealed as the risk factor more important for ROP. The oxygen supplement reveals as a protective factor until 10 days of use, up than 30 days the ROP develops earlier than other groups. The APGAR index of 5 minutes shows lower in that children who develops ROP and need treatment. In the presence of intraventicular hemorrhage the ROP occurred with more frequency and earlier. It was observed higher myopia and strabismus in the first year of children who develop ROP and was treated with cryotherapy / Doutorado / Oftalmologia / Doutor em Ciências Médicas

A hallmark of retinal diseases is degeneration of neural cells, leading to subsequent vision loss. For such diseases, replenishment of functional neural cells may be an optimal therapy. Unlike humans, the adult red-spotted newt, Notophthalmus viridescens, possesses the remarkable ability to regenerate a complete retina following its removal or injury. The purpose of this study was to develop a reproducible model of retinal damage and regeneration in the newt to understand the process of retinal regeneration. Intense light, shown in other organisms to be a relevant model of visual cell loss, was tested in the newt and resulted in variable loss of retinal function, correlating with the appearance of apoptotic cells. Due to the variability of damage observed, surgical removal of the retina was used to complement the light-damage model. A novel and non-invasive protocol using full-field electroretinography was developed to assess retinal function in vivo following damage. Measures of retinal function with the electroretinogram protocol successfully showed that photoreceptor function is initially lost and subsequently restored during regeneration. These results enhance our understanding of retinal regeneration in the adult newt and serve as a starting point for further studies aimed at determining the molecular mechanisms involved in the regeneration process.

The mechanism and the history of retinal photocoagulation are reviewed. The eye and the light beam parameters are discussed as they affect the coagulation lesion, and optimum parameters are indicated. Some comparisons are made between photocoagulators of various types. A new reason which may account for the unpredictability of the lesion size for a given exposure, the variable focal length or lens-to-retina distance of the eye, is suggested and studied. The use of a television ophthalmoscope for studying retinal coagulation generally, and in carrying out special studies in this thesis, is reported. Some unique haemorrhages and blast effects obtained during coagulation experiments are reported. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

An in vitro phagocytosis assay system was developed and characterized for studying the specific receptor-mediated phagocytosis of bovine ROS by bovine RPE cells. The phagocytosis of ROS was detected qualitatively by electron microscopy and quantitatively by treating RPE cells with radioiodinated ROS or by probing ROS-treated RPE cells with a radiolabeled antirhodopsin monoclonal antibody. The binding sites for various antirhodopsin monoclonal antibodies were localized as an essential step in their application as immunochemical probes for analysis of the structure and function of rhodopsin. Five monoclonal antibodies raised against rhodopsin have been shown to be directed against the N-terminal regions on the basis of their reactivity to an immunoaffinity purified 2-39 glycopeptide, a 2-16 tryptic glycopeptide and a 1-16 synthetic peptide as measured by radioimmune competition assays. Limited proteolysis, immunogold-dextran labeling and competitive inhibition studies identified two antirhodopsin monoclonal antibodies which bound to internal cytoplasmic loop regions of rhodopsin. Finally, the binding sites for these and other C-terminal specific antirhodopsin monoclonal antibodies were used to elucidate the proposed transmembrane helical model of rhodopsin. An antirhodopsin monoclonal antibody (rho 4D2), which bound to rhodopsin in glutaraldehyde-fixed ROS plasma membranes, was employed as an immunocytochemical probe in studying the possible role of rhodopsin in the binding and phagocytosis of rod outer segments. An immunoaffinity purified 2-39 N-terminal rhodopsin glycopeptide, a synthetic 1-16 peptide analogue of rhodopsin and phospholipid vesicles reconstituted with rhodopsin were all found to be ineffective in inhibiting the phagocytosis of ¹²⁵I-labeled ROS by RPE cells. In essence, these results provided compelling evidence that rhodopsin in the ROS plasma membrane does not function as the ligand for recognition by RPE cells. The molecular properties of the ROS cell surface ligand(s), which are involved in recognition by bovine RPE cells, were studied by limited-proteolytic digestion in conjunction with quantitative phagocytosis assays. Mildly trypsin-treated ROS were found to be less effectively phagocytized than untreated ROS by bovine RPE cells. Moreover, the glycopolypeptides (34kD and 24kD) released from the ROS cell surface by trypsin were capable of inhibiting ROS phagocytosis. The ROS plasma membrane specific, ricin-binding, 230kD glycoprotein was observed by SDS-gel electrophoresis and western blotting to be highly trypsin sensitive under these conditions. Hence, ricin affinity chromatography and immunoaffinity chromatography were employed in an attempt to purify this 230kD glycoprotein from ROS membranes. Enriched preparations of the 230kD glycoprotein were reconstituted into phospholipid vesicles and effectively used to inhibit the phagocytosis of ROS by RPE cells. In summary, a ROS plasma membrane specific, 230kD glycoprotein has been identified and isolated; this protein may act as a ligand in specific ligand-receptor interactions between ROS and RPE cells. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate

In this thesis, I use a range of techniques in computational neuroscience, communication theory, and electrophysiology to characterize functional changes that occur in early stages of retinal degeneration in the mouse. At post natal day 14, retinal ganglion cells in the rd1 mouse exhibit peculiar differences from age matched controls: an increased latency of responses to the onset of a light stimulus, decreased spike count in response to stimulus onset, increased spontaneous firing activity, and a decrease in information transmission. I propose this is due to an up-regulation of OFF bipolar cell excitation, a critical factor in functional changes seen in rd1, and use innovative techniques to discover findings that support these claims.

Both proliferative diabetic retinopathy and exudative age-related macular degeneration are major causes of blindness which are caused by growth of defective, leaky and tortuous blood vessels in the retina. Hypoxia is implicated in triggering both of these diseases and results in induction of HIF-1alpha transcription factor in addition to the angiogenic factor VEGF. Müller cells are the major glial cell in the retina and they contribute to neovascularization in hypoxic regions of the retina through eliciting secretion of growth factors, cytokines and angiogenic factors. As Müller cells span the breadth of the retina they can secrete angiostatic factors as well as neuroprotective trophic factors, the Müller cell is a valuable cell type for targeting by potential new gene therapies. The current investigation tests the hypoxia responsiveness of an AAV vector containing a hybrid hypoxia response element together with a GFAP promoter, and this vector encodes the angiostatic protein decorin, a well characterized multi-receptor tyrosine kinase inhibitor. Decorin may have advantages over other key angiostatic factors such as endostatin or angiostatin by virtue of its multiple anti-angiogenic signaling modalities. We employed Q-RT-PCR to evaluate the cell specificity and hypoxia responsiveness of an AAV-Vector termed AAV-REG-Decorin containing a hybrid HRE and GFAP promoter driving expression of the decorin transgene. The vector also contains a silencer element between the HRE and the GFAP domains to enable low basal expression in normoxia as well as high level inducibility in hypoxia. AAV-REGDecorin was found to elicit high level expression of decorin mRNA in hypoxia with greater than 9 – fold induction of the transgene in hypoxic conditions in astrocytes by comparison to normoxic astrocytes. AAV-REG-Decorin showed low levels of transgene expression by comparison to the positive control vector AAV-CMV -decorin containing the ubiquitously active CMV-promoter. The expression levels of decorin mRNA from AAV-REG-Decorin and from AAV-GFAP-Decorin were low in the PC12 neuronal cell model and in the ARPE19 line of retinal pigment epithelial cells with respect to those of AAV-CMV-decorin and no induction of Decorin mRNA was found with AAV-REGDecorin in these two control cell lines. Our novel gene therapy vector will serve as a platform for testing efficacy in rodent disease models (OIR and laser induced choroidal neovascularization) for assessment of the benefits of tightly regulated antiangiogenic gene therapy eliciting decorin transgene expression, both in terms of timing and the cellular source of production, during the progression of the retinal pathophysiology. / Includes bibliography. / Dissertation (PhD)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Publicación a texto completo no autorizada por el autor / El documento digital no refiere asesor / Analiza los resultados anatómicos y visuales de la cirugía de vitrectomía vía pars plana en el manejo del desprendimiento de retina regmatógeno en el Hospital Nacional Edgardo Rebagliati Martins. Se realizó el análisis descriptivo y retrospectivo de pacientes con DR primario con cirugía de vitrectomía pars plana en el servicio de Oftalmología del Hospital Nacional Edgardo Rebagliati Martins en el periodo 2009-2013. Se enrolaron 102 ojos de 102 pacientes y se realizó el seguimiento de un año. Se consideró los siguientes datos: edad, sexo, tiempo de enfermedad, localización de la rotura retinal, compromiso macular, cirugía realizada, agudeza visual pre y post-operatoria, éxito anatómico primario y final, complicaciones intra-operatoria y post-operatoria. El análisis se realizó mediante la prueba no paramétrica de Wilconxon y la prueba de chi.cuadrado, considerándose significativo un p<0.05. La edad media fue 59.40 años, el 66.65 % fueron hombres. La localización del desgarro más frecuente fue temporal superior 58.8%. El éxito anatómico fue de 71.6%. La agudeza visual final fue buena en el 15.69%, regular en el 36.27% y mala en un 48.04%. La complicación intra-operatoria fue el desgarro iatrogénico, las complicaciones post-quirúrgicas fueron: Hipertensión ocular, membrana epimacular, edema macular cistoide, glaucoma secundario, opacidad capsular posterior y recidiva DR. La vitrectomía pars plana en el manejo del desprendimiento de retina regmatógeno tiene un éxito anatómico de 71.6%. Existe diferencia significativa entre la agudeza visual pre y posoperatoria al año en pacientes con desprendimiento de retina Regmatógeno (p=0.000). / Trabajo de investigación

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