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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Evaluation of endothelial cell response to drug for intraocular lens delivery

Doody, Laura January 2011 (has links)
Cataract is one of the leading causes of vision loss worldwide. The rate of cataract surgery has been steadily increasing. Toxic Anterior Segment Syndrome (TASS) is a sterile inflammatory response in the anterior segment of the eye that may occur following cataract surgery. When left untreated, it can lead to permanent vision loss. Corneal endothelial cells are the cells most affected by TASS. These cells are unable to reproduce in vivo and consequently once the density of these cells drops below a certain level, vision is reduced and cannot be reversed. The damage is thought to be mediated by cytokines and endotoxins, primarily through the NF-κΒ pathway. It is hypothesized that anti-inflammatory drug delivery intraocular lenses may help reduce the occurrence of TASS and consequent vision loss. In this research thesis project, an in vitro model was developed as a tool to select drug and delivery material to be used in an anti-TASS ophthalmic biomaterial. In an attempt to find a novel and more effective approach to TASS prevention, dexamethasone, a potent anti-inflammatory steroid drug, was compared to triptolide, a cytokine inhibitor; aprotinin, a general protease inhibitor; and PPM-18, a NF-κΒ inhibitor. To assess the efficacy of these drugs, an in vitro assay using human umbilical vein endothelial cells (HUVEC) and lipopolysaccharide as a stimulant was developed. Cell response to dexamethasone (10 nM), triptolide (3 nM), aprotinin (20 μM) and PPM-18 (10 μM) with or without LPS was characterized by cell viability and flow cytometry analysis of cell activation. Activation was characterized using markers for cell adhesion and activation ICAM-1, PECAM-1, VCAM-1, β1-integrin, CD44 and E-selectin. Following preliminarily testing, the efficacy of dexamethasone (10 nM) and PPM-18 (10 μM) loaded polymer (PDMS) and copolymer (PDMS/pNIPAAm) interpenetrating polymer networks were evaluated over a 4 day release period. The results from soluble drug and LPS (100 ng/mL) testing indicated no decrease in cell viability after 24 h. Dexamethasone, triptolide, aprotinin, and PPM-18 did not reduce the significant ICAM-1 upregulation seen in HUVECs after exposure to LPS for 4 days. PPM-18 in combination with LPS significantly upregulated E-selectin iv and CD44 from unstimulated HUVEC cells. The polymer materials without drug loading did not influence the cell phenotype. However, PPM-18 delivering polymer and copolymer materials significantly upregulated VCAM-1, CD44 when compared to all other treatments. Propidium iodide uptake in HUVEC exposed to PPM-18 drug delivering polymer and copolymer treatments indicated that these treatments caused cell necrosis. None of the drugs, or the drug delivering materials were shown to counteract the upregulation seen from LPS stimulation of HUVEC cells. Future work should focus on validating the in vitro model to more closely replicate the in vivo environment of the anterior segment with the use of primary bovine corneal endothelial cells.
302

Evaluation of endothelial cell response to drug for intraocular lens delivery

Doody, Laura January 2011 (has links)
Cataract is one of the leading causes of vision loss worldwide. The rate of cataract surgery has been steadily increasing. Toxic Anterior Segment Syndrome (TASS) is a sterile inflammatory response in the anterior segment of the eye that may occur following cataract surgery. When left untreated, it can lead to permanent vision loss. Corneal endothelial cells are the cells most affected by TASS. These cells are unable to reproduce in vivo and consequently once the density of these cells drops below a certain level, vision is reduced and cannot be reversed. The damage is thought to be mediated by cytokines and endotoxins, primarily through the NF-κΒ pathway. It is hypothesized that anti-inflammatory drug delivery intraocular lenses may help reduce the occurrence of TASS and consequent vision loss. In this research thesis project, an in vitro model was developed as a tool to select drug and delivery material to be used in an anti-TASS ophthalmic biomaterial. In an attempt to find a novel and more effective approach to TASS prevention, dexamethasone, a potent anti-inflammatory steroid drug, was compared to triptolide, a cytokine inhibitor; aprotinin, a general protease inhibitor; and PPM-18, a NF-κΒ inhibitor. To assess the efficacy of these drugs, an in vitro assay using human umbilical vein endothelial cells (HUVEC) and lipopolysaccharide as a stimulant was developed. Cell response to dexamethasone (10 nM), triptolide (3 nM), aprotinin (20 μM) and PPM-18 (10 μM) with or without LPS was characterized by cell viability and flow cytometry analysis of cell activation. Activation was characterized using markers for cell adhesion and activation ICAM-1, PECAM-1, VCAM-1, β1-integrin, CD44 and E-selectin. Following preliminarily testing, the efficacy of dexamethasone (10 nM) and PPM-18 (10 μM) loaded polymer (PDMS) and copolymer (PDMS/pNIPAAm) interpenetrating polymer networks were evaluated over a 4 day release period. The results from soluble drug and LPS (100 ng/mL) testing indicated no decrease in cell viability after 24 h. Dexamethasone, triptolide, aprotinin, and PPM-18 did not reduce the significant ICAM-1 upregulation seen in HUVECs after exposure to LPS for 4 days. PPM-18 in combination with LPS significantly upregulated E-selectin iv and CD44 from unstimulated HUVEC cells. The polymer materials without drug loading did not influence the cell phenotype. However, PPM-18 delivering polymer and copolymer materials significantly upregulated VCAM-1, CD44 when compared to all other treatments. Propidium iodide uptake in HUVEC exposed to PPM-18 drug delivering polymer and copolymer treatments indicated that these treatments caused cell necrosis. None of the drugs, or the drug delivering materials were shown to counteract the upregulation seen from LPS stimulation of HUVEC cells. Future work should focus on validating the in vitro model to more closely replicate the in vivo environment of the anterior segment with the use of primary bovine corneal endothelial cells.
303

An investigation into the use of Laser Speckle Interferometry for the analysis of corneal deformation with relation to biomechanics

Wilson, Abby January 2017 (has links)
There has been widespread interest in corneal biomechanics over recent years, driven largely by the advancements in, and the popularity of refractive surgery techniques and subsequent concerns over their safety. Lately there has been interest into whether crosslinking, which is currently used for the treatment of keratoconus, could be developed as a minimally invasive technique to change the refractive power of the cornea by selectively changing the corneal biomechanics in specific regions to induce a shape change. Successful application of this technique requires a detailed understanding of corneal biomechanics and so far, little is known about the biomechanics of this complex tissue. The current lack of understanding can be mostly attributed to the absence of a suitable measurement technique capable of examining the dynamic behaviour of the cornea under physiological loading conditions. This thesis describes the development of a novel full-field, ex vivo, measurement method incorporating speckle interferometric techniques, to examine the biomechanics of the cornea before and after crosslinking in response to hydrostatic pressure fluctuations representative of those that occur in vivo during the cardiac cycle. The eventual measurement system used for the experiments detailed in this thesis incorporated; an Electronic Speckle Pattern Interferometer (ESPI), a Lateral Shearing Interferometer (LSI) and a fringe projection shape measurement system. The combination of these systems enabled the 3-dimensional components of surface displacement and the 1st derivative of surface displacement to be determined in response to small pressure fluctuations up to 1 mmHg in magnitude. The use of both ESPI and LSI together also enabled the applicability of LSI for measurement of non-flat surfaces to be assessed, and limitations and error sources to be identified throughout this work. To enable the measurement of corneal biomechanics, part of this thesis was concerned with the design of a bespoke loading rig. A chamber was designed that could accommodate tissue of both porcine and human origin. This chamber was linked to a hydraulic loading rig, whereby the cornea could be held at a baseline pressure representative of normal intraocular pressure and small pressure variations could be introduced by the automated vertical movement of the reservoir supplying the chamber. Experiments were conducted on a range of non-biological samples with both flat and curved surface topography, and both uniform and non-uniform mechanical properties, to determine if the measurement configuration was giving the expected measurement data and the loading rig was stable and repeatable. Following experiments on non-biological samples, a range of experiments were conducted on porcine corneas to develop a suitable testing methodology and address some of the challenges associated with corneal measurement, including transparency and hydration instability. During these investigations, a suitable surface coating was identified to generate an adequate return signal from the corneal surface, while not interfering with the response. Alongside this, the natural variation in the response of the cornea was investigated over the total experimental time, and a range of data was presented on corneas before and after crosslinking, which confirmed the suitability of the measurement methods for the assessment of crosslinking. Ultimately, a small sample size of six human corneas were investigated before and after crosslinking in specific topographic locations. From the experiments on human and porcine corneas, full-field maps of surface deformation have been presented, and a compliant region incorporating the peripheral and limbal areas has been identified as being fundamental to the response of the cornea to small pressure fluctuations. In addition to this, the regional effects of crosslinking in four different topographic locations on corneal biomechanics have been evaluated. From this, it has been demonstrated that crosslinking in specific regions in isolation can influence the way the cornea deforms to physiological-scale fluctuations in hydrostatic pressure and this could have implications for refractive correction.
304

Avaliação do endotélio da córnea de coelhos (oryctolagus cuniculus) em diferentes faixas etárias utilizando a microscopia especular

Brambatti, Gustavo January 2013 (has links)
O endotélio é uma monocamada de células achatadas, poligonais e interligadas que recobrem a superfície posterior da córnea, sendo fundamental na manutenção da transparência desta estrutura. Apesar dos coelhos (Orictolagus cuniculus) serem amplamente utilizados em pesquisas oftálmicas, não existem avaliações detalhadas referentes ao endotélio da córnea desta espécie em diferentes idades. Objetivou-se estudar os parâmetros morfológicos e morfométricos do endotélio da córnea de coelhos de diferentes idades, utilizando-se a microscopia especular. Foram estudados 36 bulbos oculares de 18 coelhos, machos ou fêmeas, de diferentes faixas etárias divididos em três grupos com seis animais cada, designados por: G I (animais com idade de seis meses); G II (animais com 1 ano de idade) e G III (animais com quatro anos de idade). A densidade celular endotelial média nos animais dos grupos G I, G II e G III foi de respectivamente 2307,16± 319,04, 1894,75 ± 170,81 e 1818,66 ± 245,11 células/mm2. A área celular média foi de respectivamente 364,43 ± 39,36, 374,79 ± 48,46 e de 378.50 ± 02,97 μm2 para G I, G II e G III. O pleomorfismo médio ou porcentagem de células hexagonais no endotélio central do olho direito e esquerdo de coelhos foi respectivamente de 65,40 ± 23,39% e de 75,15 ± 10,44%, com variação de 42,01 a 88,80% e de 60,71 a 81,60%. Os resultados apontam decréscimo da densidade, do pleomorfismo, e aumento da área celular média com o aumento da idade. O endotélio da córnea de coelhos sofre alterações decorrentes do avanço da idade. / The corneal endothelium is a monolayer of interconnected flattened polygonal cells that cover the back surface of the cornea, it is essential for the maintenance of its transparency. Due to the complete lack of data on the endothelial cells of rabbits (Orictolagus cuniculus) it`s ophthalmic widely used in research, no data relating to corneal endothelium in this species correlating their age. Therefore aimed to assess cell density, the average cell area and morphology of the corneal endothelium of rabbits at different ages. It was studied 36 eyes of 18 rabbits, male or female, of different ages. Rabbits were divided into three groups with 6 animals each, designated by: G I (animals aged six months), G II (animals with 1 year) and G III (animals with four years of age). The mean endothelial cell density in the animals of G I, G II and G III were respectively 2307,16± 319,04, 1894,75 ± 170,81 e 1818,66 ± 245,11 células/mm2. The average cell area was respectively 364,43 ± 39,36, 374,79 ± 48,46 e de 378.50 ± 02,97 μm2 for GI, G II and G III. The pleomorphism medium or percentage of hexagonal cells in the endothelium of the central right and left eyes of rabbits was respectively 65.40 ± 23.39% and 75.15 ± 10.44%, ranging from 42.01 to 88.80 %, and 60.71 to 81.60%. The results indicate a decrease in density, pleomorphism, and increased in average cell area with increasing age. The corneal endothelium of rabbits changes with advancing age.
305

Fenotypická charakterizace zdravé lidské rohovky a její změny při zadní polymorfní dystrofií rohovky / Phenotypical characterization of the healthy human cornea and the alterations caused by posterior polymorphous corneal dystrophy

Reinštein Merjavá, Stanislava January 2011 (has links)
Purpose: The aim of this work was to characterize the healthy human cornea and the cornea of patients suffering from posterior polymorphous corneal dystrophy (PPCD) using different antibodies. Despite the fact that PPCD is a very rare disorder, one of the largest groups of PPCD patients in the world comes from the Czech Republic. This offers us the opportunity to investigate the changes on the clinical, cellular and molecular levels. Material and Methods: A collection of 25 control corneas as well as 16 pathological corneas from PPCD patients were used. Epithelial (cytokeratins) and mesothelial markers (mesothelin, calbindin 2, HBME-1 protein) were detected in all layers of the healthy corneas using immunocyto- and immunohistochemistry. The expression of all markers was confirmed using molecular methods as well (RT-PCR and Western blot). Changes in the expression of cytokeratins and changes in the extracellular matrix structure (collagen IV and VIII) were studied in the PPCD corneas. Combined fluorescent immunohistochemistry with fluorescence in situ hybridization were used in order to characterize the origin of abnormal cells on the posterior graft surface, which cause the recurrence of the PPCD after penetrating keratoplasty surgery. Results: Changes in the cytokeratin expression (strong...
306

Zavedení nových postupů přípravy a uchování tkání pro transplantace v očním lékařství / Implementation of novel methods of tissue preparation and storage for transplantation purposes in ophthalmology

Rybičková, Ivana January 2013 (has links)
Introduction: Recent advances in posterior lamellar keratoplasty necessitated the preparation of posterior corneal lamellae even in the Czech Republic. The aim of this work was to introduce and standardize a novel method of manual preparation of corneal lamellae for Descemet Membrane Endothelial Keratoplasty with a Stromal rim (DMEK-S) in an ocular tissue bank. After setting the criteria for endothelial quality, we obtained a licence to provide the tissues for transplantation purposes. The obtained results were analysed after two years. Furthermore, a novel lamellar insertion technique using a cartridge was assessed. The potentials for the long-term storage of posterior corneal lamellae by the vitrification in liquid ethane was studied using human amniotic membrane as a model tissue. Material and Methods: Corneoscleral buttons stored in tissue cultures were used to prepare lamellae consisting of a central zone of endothelium and Descemet membrane supported by a stromal rim at the periphery. The manual preparation was performed on an artificial anterior chamber using the big bubble technique. Endothelial quality was assessed before storage, before and immediately after preparation as well as after 2 days of storage at 31řC. A group of 12 corneas with a live endothelial cell density ≥ 2500 cells/mm2...
307

Avaliação do endotélio da córnea de coelhos (oryctolagus cuniculus) em diferentes faixas etárias utilizando a microscopia especular

Brambatti, Gustavo January 2013 (has links)
O endotélio é uma monocamada de células achatadas, poligonais e interligadas que recobrem a superfície posterior da córnea, sendo fundamental na manutenção da transparência desta estrutura. Apesar dos coelhos (Orictolagus cuniculus) serem amplamente utilizados em pesquisas oftálmicas, não existem avaliações detalhadas referentes ao endotélio da córnea desta espécie em diferentes idades. Objetivou-se estudar os parâmetros morfológicos e morfométricos do endotélio da córnea de coelhos de diferentes idades, utilizando-se a microscopia especular. Foram estudados 36 bulbos oculares de 18 coelhos, machos ou fêmeas, de diferentes faixas etárias divididos em três grupos com seis animais cada, designados por: G I (animais com idade de seis meses); G II (animais com 1 ano de idade) e G III (animais com quatro anos de idade). A densidade celular endotelial média nos animais dos grupos G I, G II e G III foi de respectivamente 2307,16± 319,04, 1894,75 ± 170,81 e 1818,66 ± 245,11 células/mm2. A área celular média foi de respectivamente 364,43 ± 39,36, 374,79 ± 48,46 e de 378.50 ± 02,97 μm2 para G I, G II e G III. O pleomorfismo médio ou porcentagem de células hexagonais no endotélio central do olho direito e esquerdo de coelhos foi respectivamente de 65,40 ± 23,39% e de 75,15 ± 10,44%, com variação de 42,01 a 88,80% e de 60,71 a 81,60%. Os resultados apontam decréscimo da densidade, do pleomorfismo, e aumento da área celular média com o aumento da idade. O endotélio da córnea de coelhos sofre alterações decorrentes do avanço da idade. / The corneal endothelium is a monolayer of interconnected flattened polygonal cells that cover the back surface of the cornea, it is essential for the maintenance of its transparency. Due to the complete lack of data on the endothelial cells of rabbits (Orictolagus cuniculus) it`s ophthalmic widely used in research, no data relating to corneal endothelium in this species correlating their age. Therefore aimed to assess cell density, the average cell area and morphology of the corneal endothelium of rabbits at different ages. It was studied 36 eyes of 18 rabbits, male or female, of different ages. Rabbits were divided into three groups with 6 animals each, designated by: G I (animals aged six months), G II (animals with 1 year) and G III (animals with four years of age). The mean endothelial cell density in the animals of G I, G II and G III were respectively 2307,16± 319,04, 1894,75 ± 170,81 e 1818,66 ± 245,11 células/mm2. The average cell area was respectively 364,43 ± 39,36, 374,79 ± 48,46 e de 378.50 ± 02,97 μm2 for GI, G II and G III. The pleomorphism medium or percentage of hexagonal cells in the endothelium of the central right and left eyes of rabbits was respectively 65.40 ± 23.39% and 75.15 ± 10.44%, ranging from 42.01 to 88.80 %, and 60.71 to 81.60%. The results indicate a decrease in density, pleomorphism, and increased in average cell area with increasing age. The corneal endothelium of rabbits changes with advancing age.
308

Características clínicas e imunológicas de pacientes com ceratocone e alergia ocular: um estudo transversal com ênfase na análise da inflamação da superfície ocular / Clinical and immunological characteristics of patients with keratoconus and ocular allergy: a cross sectional study with emphasis on the analysis of ocular surface inflammation

Leda das Neves Almeida Sandrin 15 December 2016 (has links)
Objetivo: Comparar as características inflamatórias da superfície ocular de pacientes com ceratocone (CE) às de pacientes com alergia ocular (AO). Métodos: Realizou-se um estudo transversal, envolvendo 134 participantes, divididos em três grupos: alergia ocular (AO)(n=55), ceratocone com ou sem alergia ocular associada (CE) (n=61) e controle (CO) (n=18). Os participantes do estudo foram recrutados e avaliados em clínica privada na cidade de Chapecó-SC, no período de polinização, em dezembro de 2013 e de outubro de 2014 a janeiro de 2015. Para análise dos grupos, todos os pacientes foram avaliados clinicamente por especialistas em alergia e oftalmologia e submetidos a exame de tomografia de córnea com tecnologia de Scheimpflug (Pentacam HRR), medida da osmolaridade da lágrima por impedanciometria (TearLabR) em ambos os olhos e preenchimento de questionários padronizados para alergia ocular (QA) e para doença de superfície ocular (OSDI). Em 107 de 134 pacientes (CE=50, AO=42, CO=15) foram dosadas as citocinas IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, IL-15, IL-31, IL-33, IL-17 A, IL-23, TNF-alfa, TNF-beta e INF-gama na lágrima, por meio de tecnologia multiplex com beads magnéticas. A coleta das amostras de lágrimas (5 microlitros no mínimo) foi realizada por meio de aspiração no menisco lacrimal temporal inferior, com capilares de vidro em um único olho. As amostras foram congeladas imediatamente após coleta e mantidas a -80 oC, até o momento da dosagem e análise em agosto de 2016. Resultados: Constatou-se alta prevalência de alergia no grupo com ceratocone 68,85% (42/61), sendo que 42,62% (26/61) dos pacientes desse grupo apresentaram alergia ocular. A intensidade do prurido ocular foi maior nos pacientes AO e no grupo CE, do que no grupo controle (p < 0,001 e p=0,047) e maior no grupo AO do que no CE (p < 0,001). As citocinas INF-gama, IL-13, IL-15, IL-17A, IL-1beta, IL-2, IL-4, IL-5, IL-31, TNF-beta foram estatisticamente mais elevadas no grupo AO, quando comparadas ao grupo CE. No grupo controle, houve correlação direta da diferença absoluta da osmolaridade (delta osmol) com o nível encontrado para todas as citocinas dosadas. Observou-se, ainda, correlação direta entre níveis de IL-1beta, IL-6 e TNF-alfa com OSDI (p=0,044, p=0,010 e p=0,047) no grupo CE. A osmolaridade foi maior no grupo CE, quando comparado ao AO (p=0,043). Conclusões: Pacientes com ceratocone apresentaram alterações inflamatórias na superfície ocular, tais como: correlação direta do índice OSDI com IL-1beta, IL-6 e TNF-alfa na lágrima; intensidade de prurido mais elevada que no grupo controle e osmolaridade maior que no grupo com AO. No grupo AO, observou-se índices OSDI maiores que no grupo controle e aumento de várias citocinas dosadas, quando comparadas ao grupo CE. Nos pacientes controle, a instabilidade no filme lacrimal (delta osmol), correlacionou-se diretamente com a inflamação ocular (citocinas dosadas). Observou-se alta prevalência de formas leves de alergia ocular no grupo CE (40,98%) e apenas um caso de alergia ocular grave (ceratoconjuntivite atópica [1,3%]), esses dados estão em desacordo com a maior parte da literatura disponível sobre o assunto. Em conjunto, os achados do presente estudo podem estar relacionados a características específicas da região estudada / Purpose: To compare the inflammatory profile of the ocular surface of patients with keratoconus with that of patients with ocular allergy. Methods: A cross sectional study was carried out and involved 134 participants, divided into three groups: ocular allergy group (OA) (N=55), keratoconus with or without ocular allergy (KC) (N=61) and a control group (CO) (N=18). The study participants were recruited and evaluated in a private clinic in the city of Chapecó-SC, during the pollination period in 2013 (December) and from 2014 to 2015 (October to January). In order to analyze the three groups, all patients were evaluated clinically by allergy and ophthalmology specialists, submitted to a corneal tomography exam with Scheimpflug technology (Pentacam HRR), to impedanciociometry to assess tear osmolarity (Tear LabR) of both eyes and to standardized questionnaire rates for ocular allergy (AQ) and for ocular surface disease index (OSDI). Cytokines (IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p70, IL-13, IL-15, IL-31, IL-33, IL-17 A, IL-23, TNF-alfa, TNF-beta and INF-gama) levels were assessed in 107 out of 134 patients using multiplex technology with magnetic beads. Tear collection of at least 5 microliters was carried out on a single eye by suction in the inferior temporal lacrimal meniscus with glass capillaries. The samples were frozen at -800C, immediately after collection to the time of dosing and analysis in August 2016. Results: The prevalence of allergy in the keratoconus group was 68.85% (42/61), within the same group 42.62% (26/61) of the patients had ocular allergy. Ocular pruritus intensity was higher in the OA group and in the KC group than in the control group (p < 0,001 e p=0,047), and higher in the OA group than in the KC group (p < 0,001). Cytokines INF-gama, IL-13, IL-15, IL-17A, IL-1beta, IL-2, IL-4, IL-5, IL-31, TNF-beta were statiscally higher in the OA group in comparision to the KC group. In the control group, there was a positive correlation of the difference measurement of osmolarity (osmol delta) between the eyes with all cytokines dosed. In the KC group, IL-1beta, IL-6 e TNF-alfa correlated positively with OSDI (p=0,044, p=0,010 e p=0,047). Tear osmolarity was higher in the KC group than in the OA group (p=0,043). Conclusions: Patients with keratoconus had inflammatory changes in the ocular surface, such as: direct correlation between OSDI and tear IL-1beta, IL-6 and TNF-alpha levels; higher pruritus intensity than the control group and higher osmolarity than the OA group. In the OA group, OSDI levels were higher than in the control group and some cytokines had higher levels than the KC group. In the control patients, tear film instability (delta osmol) was direct correlated to ocular inflammation (dosed cytokines). In the KC group, there was a high prevalence of mild forms of ocular allergy (40.98%) and only one case of severe ocular allergy (atopic keratoconjunctivitis [1.3%]). However, most studies avaiable have associated keratoconus with severe forms of ocular allergy. Together, these findings may be related to specific characteristics of the region of study
309

QuantificaÃÃo de angiogÃnese corneana in vivo atravÃs de processamento de imagens digitais / In vivo quantification of corneal angiogenesis using digital image processing

Francisco Vagnaldo Fechine Jamacaru 24 November 2006 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Um programa de computador foi desenvolvido especificamente para a segmentaÃÃo e quantificaÃÃo de angiogÃnese corneana em imagens digitais capturadas in vivo. O propÃsito foi estabelecer um mÃtodo automÃtico para quantificar, de forma rÃpida, objetiva e acurada, a progressÃo temporal da resposta angiogÃnica. Desenvolveu-se ainda um modelo de angiogÃnese corneana inflamatÃria em coelhos, induzida por uma cauterizaÃÃo alcalina pontual, onde a resposta angiogÃnica foi avaliada, conforme cinco mÃtodos manuais, nos dias 3, 6, 9, 12, 15, 18 e 21 apÃs a cauterizaÃÃo, ocasiÃes em que tambÃm foram obtidas, de maneira padronizada, imagens digitais da cÃrnea. O software à composto de cinco mÃdulos, com funÃÃes especÃficas, que identificam e segmentam automaticamente os neovasos e quantificam a resposta angiogÃnica mediante a determinaÃÃo de trÃs parÃmetros principais: Ãrea de neovascularizaÃÃo, comprimento vascular total e nÃmero de vasos sangÃÃneos. Assim, o sistema dispensa a rotulaÃÃo prÃvia da neovascularizaÃÃo, propiciando, por conseguinte, o monitoramento espacial e temporal da resposta angiogÃnica in vivo. A avaliaÃÃo da validade do mÃtodo automÃtico proposto envolveu a determinaÃÃo do grau da correlaÃÃo entre cada um dos quantificadores automÃticos e os cinco parÃmetros manuais. Compreendeu ainda a comparaÃÃo do reconhecimento automÃtico dos vasos sangÃÃneos realizado pelo software em 50 subimagens com o reconhecimento manual efetuado, consensualmente, por trÃs examinadores (padrÃo-ouro), determinando-se entÃo a sensibilidade, especificidade e o coeficiente de concordÃncia kappa. Para avaliar a confiabilidade, trÃs examinadores utilizaram o mÃtodo automÃtico para analisar 50 imagens em dois momentos. A concordÃncia intra e interexaminadores foi medida pelo coeficiente de correlaÃÃo intraclasse. Para ilustrar a utilidade do mÃtodo automÃtico, delineou-se um ensaio que avaliou o efeito dos fÃrmacos prednisona, talidomida, Ãcido acetilsalicÃlico, etoricoxib e celecoxib no modelo de angiogÃnese corneana inflamatÃria. A anÃlise dos grÃficos dos quantificadores manuais e automÃticos revelou que a evoluÃÃo temporal da resposta angiogÃnica no modelo de angiogÃnese corneana inflamatÃria seguiu um padrÃo bifÃsico: crescimento exponencial atà o dia 12 (fase de proliferaÃÃo), seguido de crescimento linear atà o dia 21 (fase de maturaÃÃo). Constatou-se uma forte correlaÃÃo linear positiva estatisticamente significante entre os quantificadores automÃticos e manuais, denotando que o mÃtodo automÃtico mensurou a resposta angiogÃnica de forma anÃloga à realizada pelo mÃtodo manual. A sensibilidade do mÃtodo automÃtico foi 85,32%, enquanto sua especificidade foi 96,37%. A concordÃncia entre o reconhecimento manual e o reconhecimento automÃtico dos vasos sangÃÃneos foi classificada pela estatÃstica kappa como quase perfeita. A concordÃncia interexaminadores foi avaliada em seis situaÃÃes, sendo classificada como excelente em quatro delas e como boa nas outras duas. A concordÃncia intra-examinador foi mensurada em nove situaÃÃes, sendo classificada como boa em apenas uma e como excelente nas demais. AlÃm disso, o sistema automÃtico foi capaz de identificar diferenÃas na intensidade do efeito antiangiogÃnico dos diferentes fÃrmacos avaliados, possibilitando graduar a atividade inibitÃria em plena (prednisona), parcial (talidomida, Ãcido acetilsalicÃlico e etoricoxib) e insuficiente (celecoxib), demonstrando, assim, o seu valor como mÃtodo para anÃlise quantitativa de angiogÃnese. Portanto, tais dados demonstram que o sistema automÃtico proposto constitui um mÃtodo de quantificaÃÃo de angiogÃnese acurado e reprodutÃvel. / A software was developed specifically for segmentation and quantification of corneal angiogenesis in digital images acquired in vivo. The purpose was to establish an automatic method to quantify the corneal progression of the neovascular response in a rapid, objective and accurate manner. It was also developed a model of inflammatory corneal angiogenesis in rabbits induced by a punctual alkaline cauterization. Angiogenic response was evaluated at days 3, 6, 9, 12, 15, 18 and 21 after cauterization. At these occasions, digital images of cornea were also captured in a standardized fashion. The software is composed of five modules, each with specific functions, which automatically identify and segment the neovessels and quantify the neovascular response through the calculation of three main parameters: neovascularization area, total vascular length and blood vessels number. Thus, the system does not require previous enhancement of the neovascularization, so that it provides the temporal and spatial monitoring of the angiogenic response in vivo. To assess the validity of the automatic method, it was determined the correlation degree between each automatic parameters and the five manual variables. It was also evaluated by comparing automatic recognition of blood vessels performed by the software on 50 subimages with the manual recognition performed by three raters by consensus (gold-standard) and then calculating the sensitivity, specificity and kappa coefficient. To assess reliability, three raters used the automatic method for analysing 50 images at two moments. The intra and inter-raters agreement was assessed by calculating intraclass correlation coefficient. To illustrate the utility of the automatic method, it was designed an assay that evaluated the effect of prednisone, thalidomide, acetylsalicylic acid, etoricoxib and celecoxib in the model of inflammatory corneal angiogenesis. The analysis of the graphics of the manual and automatic parameters showed that the temporal progression of the neovascular response in this model followed a biphasic pattern: exponential growth until day 12 (proliferation phase), followed by linear growth until day 21 (maturation phase). It was found a statistically significant positive linear correlation between automatic and manual variables, denoting that both methods measured the angiogenic response in an analogous fashion. The sensitivity of the automatic method was 85.32% and the specificity was 96.37%. The agreement between manual and automatic recognition of blood vessels was classified as almost perfect, according to kappa statistics. The inter-raters agreement was measured in six situations and it was classified as good in two of them and as excellent in the others. Among the nine situations analysed, the intra-rater agreement was classified as good in only one of them and as excellent in the others. Furthermore, the automatic system was able to detect differences in the intensity of the antiangiogenic effect of tested drugs, allowing the inhibitory activity to be graduated as full (prednisone), partial (thalidomide, acetylsalicylic acid and etoricoxib) and insufficient (celecoxib), demonstrating, thus, its value as method for quantitative analysis of angiogenesis. Therefore, such results demonstrate that the proposed automatic system constitutes an accurate and reproducible method of angiogenesis quantification.
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Análise da ocorrência de polimorfismo de nucleotídeo único do gene DOCK9 em ceratocone / Occurrence analysis of a single nucleotide polymorphism of the gene DOCK9 in keratoconus

Reis, Leonardo Mariano 23 February 2016 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-06-06T12:33:44Z No. of bitstreams: 2 Tese - Leonardo Mariano Reis - 2016.pdf: 3509741 bytes, checksum: e1f5a9a506233e87a4136a0c0016ae8e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-06T15:32:50Z (GMT) No. of bitstreams: 2 Tese - Leonardo Mariano Reis - 2016.pdf: 3509741 bytes, checksum: e1f5a9a506233e87a4136a0c0016ae8e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-06-06T15:32:50Z (GMT). No. of bitstreams: 2 Tese - Leonardo Mariano Reis - 2016.pdf: 3509741 bytes, checksum: e1f5a9a506233e87a4136a0c0016ae8e (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2016-02-23 / Keratoconus is a non-inflammatory ocular dysfunction characterized by thinning, protrusion and conical shape of the cornea. The progression of this dysfunction leads to significant decrease in visual acuity and occasionally, in more severe cases, to corneal transplantation. The etiology of keratoconus is complex and the genetic component is among the main factors associated with the development of this disease. The objective of this study was to evaluate the occurrence of mutation in candidate genetic loci and its relation with keratoconus in patients attended in Brazil compared to healthy volunteers, through analysis of single nucleotide polymorphism in the gene DOCK9. In this clinical study, 108 participants were evaluated: 46 keratoconus patients and 62 healthy volunteers (controls). DNA samples were extracted from collected blood from keratoconus patients and controls. The genotyping of the single nucleotide polymorphism rs7995432 in the gene DOCK9 was determined through realtime polymerase chain reaction (qPCR). Single nucleotide polymorphism mutations were observed in both patients and controls. There were no significant differences on the frequency and discrimination of the mutant and wild alleles between patients and controls. The frequency of the mutant allele (C) was 4.8% in patients and 7.6% in controls. For the wild allele (T), the frequencies were 95.2% in patients and 92.4% in controls. The heterozygous genotype was present in 9.5% of patients and 11% of controls, while the homozygous genotype for the wild allele (TT) was found in 90.5% and 87% for patients and controls, respectively. Thus, these results confirm no association of these mutations and the occurrence of keratoconus for this population. / O ceratocone é uma disfunção ocular não-inflamatória caracterizada por afinamento, protrusão e formato cônico da córnea. A progressão desta disfunção ocular induz a diminuição significativa da acuidade visual em pacientes e ocasionalmente, nos casos mais avançados, ao transplante de córnea. A etiologia do ceratocone é complexa e o componente genético está entre os principais fatores associados ao seu desenvolvimento. O objetivo deste estudo foi avaliar a ocorrência de mutação em loci gênicos candidatos e sua relação com ceratocone em pacientes atendidos no Brasil comparados a voluntários saudáveis, através da análise de polimorfismo de nucleotídeo único no gene DOCK9. Neste estudo clínico foram avaliados 108 indivíduos, sendo 46 pacientes com ceratocone e 62 voluntários saudáveis (controles). Amostras de DNA foram obtidas do sangue coletado de pacientes com ceratocone e controles para a realização de análise de genotipagem. O genótipo do polimorfismo de nucleotídeo único rs7995432 no gene DOCK9 foi determinado através de reação em cadeia da polimerase em tempo real (qPCR). As mutações de polimorfismos de nucleotídeo único foram observadas em pacientes e controles. Não foram observadas diferenças significativas na frequência e discriminação dos alelos mutante e selvagem entre os pacientes com ceratocone e os controles. A frequência do alelo mutante (C) foi de 4,8% para os pacientes e 7,6% para os controles. Para o alelo selvagem (T), as frequências foram de 95,2% para os pacientes e 92,4% para os controles. O genótipo heterozigótico esteve presente em 9,5% dos pacientes e 11% dos controles, enquanto o genótipo homozigótico para o alelo selvagem (TT) foi encontrado em 90,5% e 87% para os pacientes e controles, respectivamente. Assim, não foi possível fazer uma associação destas mutações com a ocorrência do ceratocone para esta população.

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