Thesis (M. Med. Sc.)--University of Hong Kong, 2004. / Also available in print.

Thesis (Ph.D.)--Aberdeen University, 2009. / Includes bibliographical references.

Orientador: José Luiz Laus / Coorientador: Marcela Aldrovani Rodrigues / Banca: Cláudia Valéria Seullner Brandão / Banca: Marcia Rita Fernandes Machado / Banca: Paula Diniz Galera / Banca: Ivan Ricardo Martinez Padua / Resumo: Visando compreender como se comporta a organização das fibras colágenas do estroma corneal de cães por meio de propriedades birrefringentes, objetivou-se com a pesquisa mapear a supraorganização das fibras do estroma corneal de cães, de maneira setorizada e comparativa, nos diferentes sítios e fragmentos. Córneas (n=22) foram removidas de 11 cães submetidos a eutanásia por razões não relacionadas à pesquisa. Quatro córneas foram estudadas in totum, após confecção de montagens totais, e 18 foram incluídas em parafina e transversalmente seccionadas para 7 µm. Todo o material foi estudado sob microscópio de luz polarizada (Olympus BX-53 Pol, Tóquio, Japão) munido de luz policromática e monocromática de 546 nm, compensadores de Sénarmont e Brace-Köhler, e sistema para vídeo-análise de imagens. As fibras colágenas foram posicionadas a 45 e 90 graus do plano da luz polarizada (PLP) e avaliadas setorialmente, ou seja, nas regiões anterior, média e profunda dos estromas superior, inferior, central, nasal e temporal das córneas. A supraorganização das fibras colágenas foi estabelecida a partir dos valores da diferença do caminho óptico (OPD) quantificados pelo método de Sénarmont e Brace-Köhler. O tensor de estrutura, foi processado com auxílio do plugin Java "OrientationJ". Diferenças com P<0,05 foram consideradas significativas. Não foram observadas diferenças em alinhamento das fibras colágenas entre as regiões superior, inferior e central da córnea (P>0,05). As fibras colágenas no... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In order to comprehend the behavior of the organization of the canine cornea stromal collagen fibers by birefringent properties, this research aimed to map the supraorganization of the canine corneal stroma fibers, sectorial and comparatively, in different sites and fragments. Corneas (n =22) were removed from 11 dogs submitted to euthanasia for reasons not related to this research. Four corneas were fully studied, after the total montage confection, and eighteen of those were embedded in Histosec® and transversely sectioned to 7 µm. All material were studied under a polarized-light advanced microscope (Olympus BX-53 Pol, Tokyo, Japan) equipped with polychromatic and 546 nm monochromatic light, Sénarmont and Brace-Köhler compensators, and an image analysis system. The collagen fibers were positioned at 45 e 90 degrees to the polarized light plane (PPL) and evaluated by sector, that is, at the anterior, medium and deep stroma of the superior, inferior, central, nasal and temporal corneal fragments. The supraorganization of the collagen fibers was defined based on values of optical path difference (OPD) quantified by Sénarmont and Brace-Köhler method. The structure tensor, a 2x2 matrix that calculates the coherency coefficient of local pixels to inform about the orientation of the fibers in the X and Y microscopy images planes, was processed with a Java plugin named "OrientationJ". Differences were considered significant when P<0.05. No differences regarding the alignment of th... (Complete abstract click electronic access below) / Doutor

Orientador: José Luiz Laus / Coorientador: Marcela Aldrovani Rodrigues / Banca: Cláudia Valéria Seullner Brandão / Banca: Ivan Ricardo Martinez Padua / Banca: Roberta Martins Crivelaro / Banca: Marcia Rita Fernandes Machado / Resumo: Membranas a base de colágeno tipo I extraído de tendão flexor digital superficial bovino foram estudados como possível matéria prima para confecção de inlays corneais. Elas foram implantadas nos estromas corneais de olhos direitos de 16 coelhos da raça Nova Zelândia Branco, adultos, machos ou fêmeas, em higidez sistêmica. Um "bolso" foi criado na região central de cada córnea para implantação e posicionamento da membrana (inlay) dentro do estroma anterior (grupo CM, 16 coelhos). Córneas com "bolso", sem implantação de membranas (grupo SM, 16 coelhos), bem como córneas intactas (grupo controle, 4 coelhos sem qualquer procedimento cirúrgico) foram estudadas. Os grupos CM e SM foram avaliados clinicamente quanto a presença de blefarospasmo, hiperemia conjuntival, edema, secreção ocular e neovascularização e quanto às propriedades refrativas e a curvatura da córnea imediatamente antes (basal) e transcorridos 3, 7, 14, 21 e 28 dias de pós-operatório. Quatro animais dos grupos CM e SM, escolhidos ao acaso, foram submetidos à eutanásia ativa, em diferentes tempos, para colheita de córneas, as quais juntamente com córneas intactas do grupo controle, foram processadas para estudos comparativos em anisotropias ópticas (birrefringências total, de forma e intrínseca). Todas as variáveis contínuas foram testadas para a normalidade estatística. Diferenças com p < 0,05 foram consideradas significativas. Os procedimentos cirúrgicos realizados na córnea dos animais do grupo SM não alteraram a... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Membranes based on type I collagen extracted from bovine superficial digital flexor tendon were studied as a possible raw material for making corneal inlays. They were implanted in the right-eye, on the corneal stroma of 16 New Zealand White rabbits, male or female, adults, in apparently systemic health. A "pocket" was created in the central region of the cornea for implantation and positioning of the membrane (inlay) within the anterior stroma (CM group, 16 rabbits). Corneas with pocket, without implantation of membranes (SM group, 16 rabbits), as well as intact corneas (control group, 4 rabbits without any surgical procedure) were studied. The CM and SM groups were clinically evaluated for the presence of blepharospasm, conjunctival hyperemia, edema, ocular secretion and neovascularization, and on the refractive properties and curvature of the cornea immediately before (baseline) and after 3, 7, 14, 21 and 28 days of the postoperative period. Four animals, randomly choose from CM and SM groups were submitted to active euthanasia at different times to harvest the corneas, which, together with intact corneas from the control group, were processed for comparative studies in optical anisotropy (total, form and intrinsic birefringences). All continuous variables were tested for statistical normality. Differences with p <0.05 were considered significant. Surgical procedures performed on the corneas of the SM group did not alter the refraction (p = 0.479). The corneas in the CM gr... (Complete abstract click electronic access below) / Doutor

Cells of the stratified adult corneal epithelium undergo centripetal migration throughout adult life from the edge of the cornea to the centre. To date nothing is known about the mechanism underpinning the oriented cellular migration. Failure to replenish apoptotic cells lost by desquamation from the superficial layer of the corneal epithelium leads to severe pathological conditions that may result in blindness. In this study we investigated the role of planar cell polarity (PCP) core proteins as the guidance cue for centripetal migration in the cornea. Cre-mediated conditional deletion of floxed alleles of the core PCP gene Vangl2 in the corneal epithelium and lens of adult mice was achieved. The effect of this deletion was studied by microscopic and immunohistological observation of the cornea compared to littermate controls, showing defects consistent with disrupted apical-basal polarity in mutant mice. Planar behaviour of the corneal epithelial cells was assayed by breeding the mutant alleles (Le-CreTg/-; Vangl2flox/flox) and the Looptail mouse (Vangl2Lp/+) onto an X-linked LacZ reporter transgene (XLacZ) background, demonstrating the importance of PCP core components for normal cell migration. In vitro directional migration studies were performed on Vangl2 and Frizzled6 knock-down human corneal epithelial cells following the application of direct current electric fields (DC-EFs), resulting in the reduction of directional migratory response to the DC-EF. This study showed for the first time roles for the planar cell polarity (PCP) signalling in orchestrating and coordinating cellular cues that drive oriented migration in the unwounded adult corneal epithelium. It is likely that mutations in PCP genes could lead to ocular surface abnormalities in humans.

No description available.

No description available.

Thesis (MPH.) --University of Limpopo, 2018 / Background: Vernal keratoconjunctivitis (VKC) is a bilateral, chronic form of allergic eye disease characterized by inflammation of the conjunctiva and usually presents in the first decade of life. Aim: The aim of this study was to determine the factors contributing to poor treatment outcome of vernal keratoconjunctivitis in children in the Lepelle-Nkumpi municipality, Limpopo Province, South Africa. Methods: A quantitative study was conducted by using a structured questionnaire administered by the researcher to collect data at the eye clinics in Lebowakgomo and Zebediela Hospitals. A descriptive cross-sectional design was used to conduct the study. A systemic random sampling method was used to select 240 children between the ages of two and twelve years who had been diagnosed with VKC. Data was analysed by using the SPSS software program. Results: Data is presented by applying descriptive and inferential statistics. The majority of parents/guardians (80%) reported not knowing about VKC even though the condition was explained to them when their children were first diagnosed. The study shows no association between gender of the parents/guardians and knowledge of VKC (p>0.005) as indicated on Table 4.6. The study shows association between education of parents/guardians and knowledge of VKC (p<0.005) as shown by Table 4.7. The parents/principal guardians (74.2%) reported that even if they could not manage to accompany their children all the time due to work primarily, they asked their next relative to accompany their children on their behalf so that children don’t miss their review appointments. Conclusion: It was, therefore, recommended that when a child is diagnosed with VKC, the parent/guardian should be given the details about the condition along with an information pamphlet/leaflet that contains important key factors about the condition for future reference. It is also recommended that after a child has taken treatment from the hospital for three consecutive months, a prescription letter should be given to the parent/guardian to collect treatment at the nearest clinic for the next three months to ensure compliance and easy access to medication. Key words: Knowledge, Vernal keratoconjunctivitis, children, parents/guardians

<p>Corneal dystrophies are commonly referred to as an congenital condition. Surgical complications are usually worse then the primary dysfunction and patients need to go through large surgical process. Only 25 % of the patients reach driving licence vision after a surgery. The aim of this study was to investigate if the application of human embryonic stem cells (hESc) could replace epithelial cells of the human cornea. Corneal markers such as cytokeratins CK3, CK15, CK19 and Pax - 6 were analysed by immunohistochemistry. HES - Cellect was used as indication of  stem cell potential of the transplanted cells. hESc transplanted onto the cornea could be seen to attach and expand dominantly  towards Bowman’s membrane. Human embryonic stem cells in culture were relatively positive for markers, contradictionally stem cells  in the epithelial trails lost their stem differentiation  potential  and appeared to be negative for all markers used in these trails. Optimization of stem cells differentiation into epithelial which may in the future may gives us the ability to perform clinical applications with successful outcome.</p>

Corneal dystrophies are commonly referred to as an congenital condition. Surgical complications are usually worse then the primary dysfunction and patients need to go through large surgical process. Only 25 % of the patients reach driving licence vision after a surgery. The aim of this study was to investigate if the application of human embryonic stem cells (hESc) could replace epithelial cells of the human cornea. Corneal markers such as cytokeratins CK3, CK15, CK19 and Pax - 6 were analysed by immunohistochemistry. HES - Cellect was used as indication of  stem cell potential of the transplanted cells. hESc transplanted onto the cornea could be seen to attach and expand dominantly  towards Bowman’s membrane. Human embryonic stem cells in culture were relatively positive for markers, contradictionally stem cells  in the epithelial trails lost their stem differentiation  potential  and appeared to be negative for all markers used in these trails. Optimization of stem cells differentiation into epithelial which may in the future may gives us the ability to perform clinical applications with successful outcome.