published_or_final_version / Anatomy / Master / Master of Medical Sciences

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published_or_final_version / abstract / Medicine / Master / Doctor of Medicine

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

Orientador: Renée Laufer Amorim / Coorientador: José Luiz Laus / Banca: Juliany Quitzan Gomes / Banca: Alvio Isao Shiguematsu / Resumo: Não disponível / Abstract: Purpose: The aims of this study were to better understand the mechanism of cell death by apoptosis in a glaucoma model (ischemia / reperfusion) and evaluate the role of apoptosis in this model and if treatment with Sildenafil helps prevent apoptosis. Methods: 36 rats, from 4 to 6 months, males, Lewis and weighing ± 350g were divided in 5 groups: control group (6 animals) and for groups with ischemia / reperfusion (7 and 21 days), two groups consisting of ten animals treated with sildenafil and two groups of Five animals treated with placebo. Paracentesis of the anterior chamber with needle 30G coupled to saline (0.9%) was made and maintained for 60 minutes. Intraocular pressure was measured by rebound tonometer (Tonovet®). There was histological, morphometric by hematoxylin and eosin and, immunohistochemical staining and qRT-PCR analysis by Caspase-7, Caspase-6, Caspase-9, Tnf-r2, Fas-l, Bcl-2 and Bax. For statistic analysis we used ANOVA and t-test for morphometric analysis and, for immunohistochemistry and qRT-PCR, Fisher exact test was employed with a statistical significance level of p <0.05 Results: Histology and morphometric analysis, proved more changes in the untreated group compared to the treatment and control group. Analysis of immunohistochemistry and qRT-PCR observed the more significant expression in untreated eyes. Conclusion: Sildenafil apperead to be protective to ganglion cell apoptosis. Cell survival was evident in histology and morphometry. For immunohistochemistry and RT-PCR was observed protective effect in the apoptosis pathways with similar or below expression compared to the control / Mestre

Diabetic retinopathy (DR) was characterized by numerous hyperglycemia-dependent cellular and pathological changes in the retina, including retinal ischemia/reperfusion (I/R) injury. To determine the role of the 2nd enzyme of polyol pathway in relation with the pathogenesis in ischemic retinopathy, SDH deficient mice, C57BL/LiA, that lacked SDH activity, was used to study the pathogenesis of diabetic retinopathy, which also included I/R injury. Wild type and SDH-deficient mice were subjected to I/R injury by transiently occluding middle cerebral artery for two hours and twenty-two hour of reperfusion. The rationale of this study was to investigate the effect by blocking the conversion of sorbitol to fructose by SDH null mutation (SDH -/-), leading to accumulation of sorbitol level and reduction of oxidative stress, as demonstrated by the polyol pathway. Results: After induction with transient MCAO, there was increase in the thickness of OLM to ILM ipsilateral SDH+/+ compared with contralateral SDH+/+ (from 84 +/- 1 to 96 +/- 2 μm) while that of ipsilateral SDH-/- compared with contralateral SDH -/- (from 77 +/- 2 to 90 +/- 2 μm) suggested that there was edema after ischemic reperfusion injury. The result showed that there was increased cellular edema in ipsilateral retina of both SDH +/+ and SDH -/- retina after transient MCAO. The level of immunoreactivity against Aquaporin-4 and nitrotyrosine in studying the presence of oxidative stress; glutamine synthetase and glutamate in studying the toxicity of astrocyte glutamate; sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) in studying the regulation Ca2+ homeostasis was determined using immunohistochemistry. For all the antibodies, there was similar immunoreactivity level between the contralateral side of both SDH+/+ and SDH -/- mice. For the SDH+/+ group, there was increase in signal in the ipsilateral retina in comparison with the contralateral one. On the other hand, for the SDH-/- group, similar result was observed. There was increase in signal and it was found more in the ipsilateral retina in comparison with the contralateral retina. Finally, in the ipsilateral retina of both SDH +/+ and SDH -/- mice, increased immunoreactivity was found in both but their difference was not statistically significant. This concluded that SDH deletion and subsequent accumulation of sorbitol metabolites did not contribute significantly in the role of pathogenesis of ischemic retinopathy especially in mice after I/R injury. / published_or_final_version / Anatomy / Master / Master of Medical Sciences

Made available in DSpace on 2015-12-10T14:23:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-05-28. Added 1 bitstream(s) on 2015-12-10T14:29:18Z : No. of bitstreams: 1 000852681.pdf: 1224340 bytes, checksum: 7e3993edae8f0d4badfed835114ffa9b (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Purpose: The aims of this study were to better understand the mechanism of cell death by apoptosis in a glaucoma model (ischemia / reperfusion) and evaluate the role of apoptosis in this model and if treatment with Sildenafil helps prevent apoptosis. Methods: 36 rats, from 4 to 6 months, males, Lewis and weighing ± 350g were divided in 5 groups: control group (6 animals) and for groups with ischemia / reperfusion (7 and 21 days), two groups consisting of ten animals treated with sildenafil and two groups of Five animals treated with placebo. Paracentesis of the anterior chamber with needle 30G coupled to saline (0.9%) was made and maintained for 60 minutes. Intraocular pressure was measured by rebound tonometer (Tonovet®). There was histological, morphometric by hematoxylin and eosin and, immunohistochemical staining and qRT-PCR analysis by Caspase-7, Caspase-6, Caspase-9, Tnf-r2, Fas-l, Bcl-2 and Bax. For statistic analysis we used ANOVA and t-test for morphometric analysis and, for immunohistochemistry and qRT-PCR, Fisher exact test was employed with a statistical significance level of p <0.05 Results: Histology and morphometric analysis, proved more changes in the untreated group compared to the treatment and control group. Analysis of immunohistochemistry and qRT-PCR observed the more significant expression in untreated eyes. Conclusion: Sildenafil apperead to be protective to ganglion cell apoptosis. Cell survival was evident in histology and morphometry. For immunohistochemistry and RT-PCR was observed protective effect in the apoptosis pathways with similar or below expression compared to the control

The purpose of this dissertation was to understand how genetics, socioeconomic status (SES), and lifestyle factors influence the development of age-related macular degeneration (AMD), glaucoma, and diabetic retinopathy in an adult population in Dallas County. Two hundred fifty-three older adults participated in this study as the sample. Crosstabulation and binary logistic regression were utilized to analyze the data. Results indicated a disparity among participants' test scores, visual health status, and perceptions of their visual impairment and highlighted the fact that many seniors are not educated about age-related retinal disorders. Furthermore, variables reaching statistical significance were consistent with the literature included race/ethnicity, age, having a family history of both AMD and diabetes, frequency of eye exams, and level of education. The results not consistent with the literature as affecting visual health included health insurance, access to health care, body weight, and smoking status. Recommendations for future study included applied research focusing on determining risk factors, raising awareness, educating, and providing early detection of these diseases among low to middle income Caucasian, African American, and Hispanic older adults.

Liu, Ke. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 175-198). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Ng, Tsz Kin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 151-185). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.