Rozprawy doktorskie na temat „Cornea”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Cornea.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Cornea”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
McGowan, Sara L. "Stem cell markers in the posterior limbus and cornea". Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2007r/mcgowan.pdf.
Pełny tekst źródła
2
Ahearne, Mark. "Mechanical characterisation of cornea and corneal stromal equivalents". Thesis, Keele University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.573762.
Pełny tekst źródła
3
Williams, Susan R. "Role of Mal/TIRAP in TLR2- and TLR4-, but not TLR5-Induced Corneal Inflammation". Cleveland, Ohio : Case Western Reserve University, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1259983828.
Pełny tekst źródła
4
Schultes, Klaus. "Ultrastructural characterization of ultraviolet induced corneal disease : an animal model". Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/27046.
Pełny tekst źródłaStreszczenie:
The majority of ancient people worshipped the sun and viewed it as a health - bringing deity. During the eighteenth and nineteenth century therapeutic benefits of sunlight exposure were beginning to be understood and by the end of the nineteenth century the importance of ultraviolet radiation was being realized. Danish physician Niels Finsen, whom many regard as the father of ultraviolet phototherapy, also stressed that it was ultraviolet radiation in the solar spectrum which cause sunburn. We now recognize that the small portion of ultraviolet radiation which reaches the earth's surface is not necessarily therapeutic, but in fact could be harmful to humans. There are numerous accounts of the harmful effects of UV radiation to the skin and the eye as a whole. These effects may be caused by either acute or chronic exposure to UV radiation. For example, some acute effects of UV-B radiation include conjunctivitis and photokeratitis. "Snow blindness" and "arc welders eye" are further examples of acute ultraviolet damage specifically to the surface of the cornea. On the other hand, chronic exposure to ultraviolet radiation is thought to be responsible for pterygia, climatic droplet keratopathy Hill and Maske (1989), cancers of the external eye, cataracts and various types of retinal diseases. The present study is an extension of ongoing studies on ultraviolet radiation damage to the cornea in the Department of Ophthalmology, University of Cape Town and Groote Schuur Hospital. Their specific interest lies in the causes and treatment of climatic droplet keratopathy. The aims of the present study are: 1) Establish a possible role of ultraviolet B radiation in human corneal diseases such as climatic droplet keratopathy and pterygium using the rabbit as an animal model. 2) Determine by means of SEM the initial effects and subsequent recovery of the epithelium after a 3-hour dose of ultraviolet B radiation. We refer to this study as "acute" response to ultraviolet B radiation. 3) To try and confirm the effects observed by SEM with ultrastructural studies using TEM. 4) In addition, we are also looking at the possible effects after exposing rabbit cornea to a daily dose of low level ultraviolet B radiation, over a long period of time. We refer to this as chronic exposure to ultraviolet B radiation. It is hoped that by exposing rabbits to ultraviolet light, principally ultraviolet B radiation, diseases similar to those found in humans could be simulated and disease progression studied. People are generally exposed to substantial amounts of UV radiation for a very long time. Since people generally live longer they will be exposed to an ever-increasing amount of solar UV radiation and subsequently, there is an increasing risk of developing corneal diseases. The possible threat to the ozone is also a real possibility and could lead to increased levels of ultraviolet radiation reaching the earth's surface. This will require a greater understanding of the very nature of corneal damage due to acute and chronic exposure. This study focusses mainly on the acute response to UV-B radiation since most studies have investigated effects of prolonged exposure to UV light. Accordingly, much less is known about acute exposure. Many people suffering from acute UV B radiation effects probably never visit the ophthalmologist or wait for a couple of days. This could also contribute to the fact that effects of short-term damage is not well documented.
5
Chmulíková, Mária. "Očné centrum Cornea". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372034.
Pełny tekst źródłaStreszczenie:
The subject of the master thesis is the design of an eye center. It’s a three-floored building, where in the first floor is designed eye optics, pharmacy and main entrance to the eye center. During the design of the building, emphasis is placed on people with reduced mobility and orientation, technical building solution, thermal technical solution, as well as the assessment of fire safety. On the second floor there is an eye clinic and an operating theatre. On the third floor there are designed an operating theatre, a conference room and offices. The two types of roofs are designed - a vegetation flat roof and a walkable flat roof.
6
Martins, Luís Carlos [UNESP]. "Avaliação ultra-estrutural do endotélio corneal de ratos normais e de diabéticos aloxânicos". Universidade Estadual Paulista (UNESP), 2002. http://hdl.handle.net/11449/88910.
Pełny tekst źródłaStreszczenie:
Made available in DSpace on 2014-06-11T19:23:40Z (GMT). No. of bitstreams: 0
Previous issue date: 2002Bitstream added on 2014-06-13T19:09:41Z : No. of bitstreams: 1
martins_lc_me_botfm.pdf: 1919468 bytes, checksum: d4a42d395d3517a07ebafa18c26a4e02 (MD5)O objetivo do estudo foi avaliar a influência do diabetes experimental sobre a ultra-estrutura do endotélio corneal de ratos. O estudo foi prospectivo, utilizando 20 ratos da raça Wistar, com 3 meses de idade, divididos em: grupo controle (GC), contendo 10 ratos, e grupo diabético (GD), contendo 10 ratos. A indução do diabetes foi feita com injeção de Aloxana endovenosa 42 mg/kg de peso (M0), após o que os animais foram observados por 15 dias para confirmar a presença de diabetes grave (M1). Um mês após M1 (M2) e 12 meses após M1 (M3) os animais foram sacrificados, sendo removidos e preparados os olhos para avaliação à microscopia eletrônica de transmissão. Os animais do GD mostraram importante redução de peso, aumento da injestão hídrica e aumento da diurese em relação aos ratos do GC. Na avaliação morfológica observou-se nos animais do GC corpos densos e figuras de Mielina no M3. Os ratos do GD apresentaram as mesmas alterações encontradas no GC em M3, em maior intensidade, com alterações nucleares e citoplasmáticas, como mitocôndrias bastante alteradas na forma e tamanho, rarefação do citoplasma e aumento de vesículas. Os ratos do GD em M3 apresentaram mais alterações que os do GDM2. Conclui-se que o diabetes experimental causa dano ultra-estrutural no endotélio corneal de ratos e que as alterações são evolutivas.
The objective of study was to make na assessment of experimental diabetes influence on of rats corneal endothelium ultra-structure. The study was prospective, using 20 Wistar 3-month-old rats, divided (by draw) into groups: control group (GC), with 10 rats, and diabetic group (GD), with 10 rats. The diabetes induction was made by means of intravenous injection of Aloxan 42 mg/Kg weigth. After the diabetes induction (M1), the animals had been observed for 15 days, and then, 1 month after M1 (M2) and 12 months after M1 (M3) to confirm the diagnosis of severe diabetes. At experimental moments M2 and M3, the animals eyes enucleation and preparation were carried out for assessment trough transmission eletronic microscopy. GD animals had shown significant reduction of weigth, increasing of hydric and nourishing injection and increasing of diuresis in relation to GC rats. In the morphological assessment, dense bodies and Myelin figures were observed in M3 GC animals. GC rats had presented the same alterations found in GC animals in M3, in major intensity, beyond mitochondrias rather modified in their form and size, cytoplasm rarefaction, vesicles increasing and nuclear alterations. It is concluded that experimental diabets causes ultra-structural of rats corneal endothelium.
7
Glavine, Kristin Ann. "Using corneal characteristics to predict corneal change in overnight orthokeratology /". Adobe Acrobat Reader required to view document, 2009. http://www.neco.edu/library/theses/GlavineThesisApr09.pdf.
Pełny tekst źródła
8
Rodrigues, Giovanna Giuffrida. "Avaliação de úlceras de córnea complicadas em cães, tratadas com a membrana de poli(butileno adipato-cotereftalato) (PBAT) e amido termoplástico (TPS) /". Araçatuba, 2017. http://hdl.handle.net/11449/151526.
Pełny tekst źródłaStreszczenie:
Orientador: Alexandre Lima de AndradeBanca: Flávia de Rezende Eugênio
Banca: Natalie Bertelis Merlini
Resumo: A ceratite ulcerativa é uma condição comum e importante e ocorre quando o epitélio e uma quantidade variável de estroma são perdidos. Atualmente, tem-se estudado o emprego de membrana de polímeros sintéticos, para reparação tectônica, em substituição aos tecidos biológicos. O presente trabalho teve como objetivo avaliar o tratamento, por ceratoplastia lamelar com o uso da membrana de Poli(butileno adipato-co-tereftalato) (PBAT) / Amido Termoplástico (TPS), de úlceras de córnea de seis cães da rotina clínica. Foram avaliados os aspectos clínicos quanto a: blefarospasmo, hiperemia conjuntival, secreção ocular, vascularização corneal, e sinais de extrusão da membrana aos terceiro, sétimo, décimo quinto e trigésimo dias de posoperatório (M3, M7, M15, M30). Com os valores obtidos, foi realizada análise descritiva dos resultados, com cálculo de porcentagem e mediana dos dados e escores adotados. Quanto ao blefarospasmo, este foi leve até M3, tornando-se ausente em M30. A secreção ocular esteve sob forma leve até o M7 e se tornou ausente até o M30. Com relação à hiperemia conjuntival, observou-se que foi intensa no M0 e regrediu temporalmente até M15. A vascularização corneal teve importância clínica a partir de M7, tornando-se intensa no M15 e moderada no M30. Após remoção da membrana, observou-se cicatrização corneal e manutenção da estrutura do bulbo do olho. Com base nos resultados obtidos e nas condições aqui estabelecidas, é possível concluir que a membrana de PBAT/TPS consti... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: - Ulcerative keratitis or corneal ulcer is a common and important condition and occurs when the epithelium and a variable amount of stroma are lost. Nowadays, the use of synthetic polymer membranes has been studied for tectonic repair, replacing biological tissues. The aim of this study was to evaluate the treatment of corneal ulcers of six dogs from clinical routine by interlamellar keratoplasty with Poly(butylene adipate-co-terephthalate) (PBAT) / Thermoplastic Starch (TPS) membranes. The clinical aspects regarding blepharospasm, conjunctival hyperemia, ocular secretion, corneal vascularization, and membrane extrusion signals at third, seventh, fifteenth and thirtieth postoperative days (M3, M7, M15, M30) were evaluated. With the obtained data a descriptive analysis of the results was performed, with calculation of percentage and median of the data and adopted scores. As for blepharospasm, it was mild to M3, becoming absent in M30. The ocular secretion, was in light form until the M7, and became absent until the M30. Conjunctival hyperemia was observed to be intense in M0 and regressed temporarily to M15. The corneal vascularization had clinical importance from M7, becoming intense in M15 and moderate in M30. After removal of the membrane, corneal healing was observed, and the structure of the eye bulb was maintained. Based on the results obtained and the conditions established herein, it is possible to conclude that the PBAT / TPS membrane is a viable alternative to lamellar keratoplasty
Mestre
9
Podskochy, Alexander. "Ultraviolet radiation and cornea /". Stockholm : Karolinska institutet, 2002. http://diss.kib.ki.se/2002/91-7349-118-7/.
Pełny tekst źródła
10
Alharbi, Ahmed A. Optometry & Vision Science Faculty of Science UNSW. "Corneal response to overnight orthokeratology". Awarded by:University of New South Wales. School of Optometry and Vision Science, 2005. http://handle.unsw.edu.au/1959.4/22515.
Pełny tekst źródłaStreszczenie:
Orthokeratology (OK) is the reduction, modification or elimination of myopia through application of contact lenses. With the development of high Dk/t lens materials, overnight therapy has become the modality of choice for OK. Overnight OK lens wear has been previously investigated in terms of its efficacy to reduce myopia. However, the underlying effects of overnight OK lens wear on the human cornea have received less attention. As well as the clinical efficacy of overnight OK, this study investigated the effects of overnight OK on topographical corneal thickness and the overnight corneal edema response, and corneal tissue changes with overnight OK. Eighteen subjects participated as the OK lens-wearing group, wearing BE lenses (UltraVision, Brisbane, Queensland) in both eyes. A further ten subjects participated as control subjects, wearing conventional rigid lenses (J-Contour, UltraVision) in the right eye (RE) only. The left eye (LE) acted as a non-lens-wearing control. Both groups wore lenses overnight only, with no lens wear during the day. Measurements were conducted at baseline then on day 1, 4, 10, 30, 60, and 90 for the OK lens-wearing eyes; and up to day 30 for the control group, in the morning (after overnight lens wear) and in the evening (after 8-10 hours of lens removal). Variables measured included best vision sphere (BVS), unaided logMAR visual acuity (VA), refractive astigmatism, apical corneal power (ACP), simulated K readings (Medmont E300 corneal topographer), topographical corneal thickness (Holden-Payor optical pachometer), and keratocyte and endothelial cell densities (ConfoScan2 confocal microscope). Approximately 75% of myopia was corrected after the first night of OK lens wear and the changes in refractive error stabilised by day 10. By day 90, myopia reduction averaged 2.54 ?? 0.63 D. This was associated with significant improvement in unaided VA of about 82% after the first night of lens wear. There was no change in refractive astigmatism over the 3-month period. There was significant reduction in ACP in the OK lens-wearing eyes after the first night of lens wear, which accounted for more than 70% of the total ACP change over the 3-month period (RE: -2.16 ?? 0.53 D; LE: -2.11 ?? 0.86 D). There was significant central epithelial thinning (about 30%) and significant thickening (about 3%) in the mid-peripheral stroma in the OK lens-wearing eyes. Significant central epithelial thinning was found after the first night of lens wear while thickening in the mid-peripheral stroma reached statistical significance by day 4. Further analysis suggests that topographical corneal thickness changes account for the refractive error changes with overnight OK lens wear, rather than corneal bending. The central overnight stromal edema response was significantly reduced in the OK lens-wearing eyes (1.2 ?? 0.5%) to a level lower than in the conventional RGP (6.2 ?? 1.2%) and non-lens-wearing eyes (2.5 ?? 0.9%) in the control group. Mid-peripheral and peripheral stromal edema responses showed similar levels to those predicted based on lens Dk/t. A single overnight wear of BE and Paragon Corneal Refractive Therapy (CRT) lenses showed that the edema response to BE lens wear is significantly less than in the CRT lens-wearing eyes (BE: 2.5 ?? 0.7%; CRT 3.5 ?? 1.3%) immediately on eye opening. No significant changes were found in either central stromal keratocyte or endothelial cell densities in either OK or control groups over the study period. In conclusion, overnight OK lens wear induces significant reductions in myopia after the first night of lens wear associated with improvement in unaided VA. Overnight OK lens wear causes significant thinning in the central epithelium and significant mid-peripheral stromal thickening which results in flattening of the central cornea and steepening in the mid-periphery. Although there were no significant changes in central stromal keratocyte and endothelial cell densities, thinning of the central epithelial layer raises concerns regarding the safety of the procedure, especially with the alarming number of corneal infections reported recently in the literature.
11
Bianchi, Arianna. "Epithelial-mesenchymal interactions in the cornea : development of a novel 3D culture cornea model and progress towards environmental reprogramming of cornea epithelium". Thesis, University of Newcastle upon Tyne, 2015. http://hdl.handle.net/10443/3033.
Pełny tekst źródłaStreszczenie:
The unmet need for corneal epithelial cells for treating human eye diseases makes the cornea important in the cell therapy field. Additionally cornea tissue engineering has become valuable for clinical use, research, and for creating representative models replacing animals for chemical/drug testing. This study initially used qPCR to investigate the expression levels of key markers produced by 2D corneal epithelial cell cultures after wounding in a scratch assay. Then an attempt was made to environmentally reprogram human hair follicle keratinocytes into corneal epithelial cells using limbal epithelial stem cell media. Immunohistochemical and qPCR analysis revealed no changes in signature genes but rather a similarity between HFC and LSC’s when cultured in LSC’s culture conditions. Attention then focused on developing a novel three-dimensional bilayered spheroid cornea model using hanging drop culture. It is widely accepted that cells in 3D culture more closely mimic their in vivo counterparts than 2D cultures, and qPCR and immunofluorescence analysis of 3D spheroids made from cultured rabbit corneal stromal cells revealed that they partially reverted back to a quiescent in vivo phenotype. Coating the spheroids with cultured rabbit limbal epithelial cells produced a bilayered model of the cornea. Multiple iterations were produced incorporating variations in media and cell origin, leading to a cornea model that could be maintained for 10 days, expressed appropriate cytokeratins and other corneal markers including Pax6 and that, upregulated the expression of key cornea signature proteins including Aldh1a1 as a result of epithelial-mesenchymal interactions. Preliminary versions of a human bilayered cornea model were then created from equivalent human cell types. Generally this 3D model displays advantages over other in vitro cornea equivalents and has potential, but needs further refinement. The methodology was also used to coat stromal spheroids with skin keratinocytes, highlighting the possibility of reprogramming the former into corneal epithelial cells through epithelial-mesenchymal interactions.
12
Etheredge, LaTia Shaquan. "The Effect of Growth Factors on the Corneal Stroma Extracellular Matrix Production by Keratocytes". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003238.
Pełny tekst źródła
13
Conceição, Luciano Fernandes da. "Efeitos do cetorolaco de trometamina 0,5%, sem conservante, sobre a resposta inflamatória, a sensibilidade e re-epitelização corneal em coelhos submetidos a ulceração química da córnea /". Jaboticabal : [s.n.], 2010. http://hdl.handle.net/11449/95527.
Pełny tekst źródłaStreszczenie:
Orientador: José Luiz LausBanca: Paola Castro Moraes
Banca: Cristiane dos Santos Honsho
Resumo: Estudou-se os efeitos do cetorolaco de trometamina 0,5%, sem conservante, sobre a inflamação ocular, avaliando-se a reparação epitelial e a sensibilidade corneal, em coelhos submetidos à ulceração corneal química com hidróxido de sódio (NaOH) 1 mol/L. Constituíram-se dois grupos (n=12). O primeiro grupo recebeu 30 μl de cetorolaco de tometamina 0,5%, sem conservante (OT), a cada seis horas, em uma das córneas ulceradas e 30 μl de solução salina fisiológica 0.9% (OC) na córnea adelfa, totalizando 4 aplicações diárias, por um período de 24 horas. O limiar de sensibilidade corneal foi avaliado por estesiometria antes e posteriormente a lesão ser realizada, a intervalos regulares de quatro horas. Avaliou-se ainda o edema corneal, a hiperemia conjuntival, o blefarospasmo e o diâmetro das úlceras, empregando-se, biomicroscópio com lâmpada em fenda, teste do tingimento pela fluoresceína, imagem digitalizada para posterior avaliação em programa Image J, até a reepitelização completa. Decorridas 24 horas da abrasão nos animais do primeiro grupo (n=6) e 55 horas nos animais do segundo grupo (n=6), estes foram submetidos à eutanásia. Ambas as córneas (OT e OC) foram avaliadas histologicamente e à microscopia eletrônica de varredura. Utilizou-se Análise de Variância para Medidas Repetidas, considerando significativos os valores de p ≤ 0,05. Conclui-se que mesmo sem a adição de conservantes e a despeito do bom efeito analgésico, o cetorolaco de trometamina a 0,5%, sem conservante, retarda a reparação cicatricial do epitélio corneal em coelhos submetidos a abrasões com hidróxido de sódio 1 mol/L.
Abstract: Studied the effects of ketorolac tromethamine 0.5% without preservatives on ocular inflammation, evaluating the sensitivity and corneal epithelial repair in rabbits subjected to chemical corneal ulceration with sodium hydroxide (NaOH) 1 mol / L. Constituted two groups (n = 12). The first group received 30 μl of tometamine ketorolac 0.5%, without preservative (OT) every six hours in one of ulcerated corneas and 30 μl of saline solution 0.9% (OC) in the other cornea a total of four applications daily for a period of 24 hours. The threshold of corneal sensitivity was assessed by esthesiometry before and after the injury to be held at regular intervals of four hours. It was also evaluated corneal edema, conjunctival hyperemia, blepharospasm and the diameter of the ulcers, using, biomicroscopy with slit lamp, the fluorescein dye test, the scanned image for further evaluation in program Image J, until complete reepithelialization. After 24 hours of abrasion in the animals of first group (n = 6) and 55 hours in animals of the second group (n = 6), they were euthanized. Both corneas (OT and OC) were evaluated histologically and scanning electron microscopy. We used ANOVA for repeated measures, considering significant p values ≤ 0.05. We conclude that even without the added preservatives and despite the good analgesic effect of ketorolac tromethamine 0.5%, without preservative, slowing the repair of corneal epithelium wound healing in rabbits subjected to abrasion with sodium hydroxide 1 mol/L.
Mestre
14
Martins, Luís Carlos. "Avaliação ultra-estrutural do endotélio corneal de ratos normais e de diabéticos aloxânicos /". Botucatu : [s.n.], 2002. http://hdl.handle.net/11449/88910.
Pełny tekst źródłaStreszczenie:
Orientador: Silvana Artioli SchelliniResumo: O objetivo do estudo foi avaliar a influência do diabetes experimental sobre a ultra-estrutura do endotélio corneal de ratos. O estudo foi prospectivo, utilizando 20 ratos da raça Wistar, com 3 meses de idade, divididos em: grupo controle (GC), contendo 10 ratos, e grupo diabético (GD), contendo 10 ratos. A indução do diabetes foi feita com injeção de Aloxana endovenosa 42 mg/kg de peso (M0), após o que os animais foram observados por 15 dias para confirmar a presença de diabetes grave (M1). Um mês após M1 (M2) e 12 meses após M1 (M3) os animais foram sacrificados, sendo removidos e preparados os olhos para avaliação à microscopia eletrônica de transmissão. Os animais do GD mostraram importante redução de peso, aumento da injestão hídrica e aumento da diurese em relação aos ratos do GC. Na avaliação morfológica observou-se nos animais do GC corpos densos e figuras de Mielina no M3. Os ratos do GD apresentaram as mesmas alterações encontradas no GC em M3, em maior intensidade, com alterações nucleares e citoplasmáticas, como mitocôndrias bastante alteradas na forma e tamanho, rarefação do citoplasma e aumento de vesículas. Os ratos do GD em M3 apresentaram mais alterações que os do GDM2. Conclui-se que o diabetes experimental causa dano ultra-estrutural no endotélio corneal de ratos e que as alterações são evolutivas.
Abstract: The objective of study was to make na assessment of experimental diabetes influence on of rats corneal endothelium ultra-structure. The study was prospective, using 20 Wistar 3-month-old rats, divided (by draw) into groups: control group (GC), with 10 rats, and diabetic group (GD), with 10 rats. The diabetes induction was made by means of intravenous injection of Aloxan 42 mg/Kg weigth. After the diabetes induction (M1), the animals had been observed for 15 days, and then, 1 month after M1 (M2) and 12 months after M1 (M3) to confirm the diagnosis of severe diabetes. At experimental moments M2 and M3, the animals eyes enucleation and preparation were carried out for assessment trough transmission eletronic microscopy. GD animals had shown significant reduction of weigth, increasing of hydric and nourishing injection and increasing of diuresis in relation to GC rats. In the morphological assessment, dense bodies and Myelin figures were observed in M3 GC animals. GC rats had presented the same alterations found in GC animals in M3, in major intensity, beyond mitochondrias rather modified in their form and size, cytoplasm rarefaction, vesicles increasing and nuclear alterations. It is concluded that experimental diabets causes ultra-structural of rats corneal endothelium.
Mestre
15
Bakkar, May. "An investigation of solution-induced corneal staining using an in vitro model". Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/an-investigation-of-solutioninduced-corneal-staining-using-an-in-vitro-model(d0a5bdfd-37af-4e4f-8db5-d72330e5739c).html.
Pełny tekst źródłaStreszczenie:
Purpose: Solution-induced corneal staining (SICS) has been the subject of much debate in the clinical literature. While it has been suggested that this form of staining indicates toxicity of the cornea, microscopy studies have suggested that cells treated with multi-purpose solutions (MPS) known to produce SICS in vivo are undamaged. There is further debate in the literature as to whether or not sodium fluorescein (‘fluorescein’) actually enters epithelial cells or not. The aim of this work was to investigate the cellular mechanisms involved in SICS by developing an in vitro cell culture model to mimic the clinical presentation of this phenomenon. Methods: An in vitro model of SICS was developed using cultured cells that were exposed overnight to ReNu MultiPlus® (Bausch + Lomb) MPS. After addition of fluorescein, cells were imaged using an automated fluorescence microscope. Hyperfluorescent cells were identified using predetermined threshold of intensity in fluorescence microscope, and confocal microscopy was used to investigate where fluorescein was situated within the cells. The extent of cell toxicity was assessed using propidium iodide and Annexin V. In order to examine the contribution of passive and active transport mechanisms in fluorescein uptake and release, levels of hyperfluorescent staining were measured at 37°C and 4°C. In all described experiments, fluorescein staining was expressed by the proportion of hyperfluorescent cells in the total cells. Results: All cultured cells readily took up fluorescein at room temperature, however a sub-population of cells stained more intensely with fluorescein. These cells were termed ‘hyperfluorescent’ cells. Exposure to ReNu MultiPlus® resulted in a significant increase in the proportion of hyperfluorescent cells compared with control cells. In addition, the staining profiles of individual cells showed no correlation between cell death and hyperfluorescence. The data also showed that hyperfluorescence did not occur extensively in deliberately lysed cells.Addition of fluorescein to the cells at 4°C resulted in very low levels of hyperfluorescence compared to high levels at 37°C. Fluorescein was rapidly released from cells at 37°C but not from those at 4°C. Conclusion: In this work, an effective in vitro model of SICS was developed in order to provide a better understanding of the mechanisms involved in fluorescein staining. This work suggests that corneal fluorescein staining may reflect a simple cellular uptake of fluorescein. Levels of staining in the cells appear to be unrelated to cellular toxicity or cell damage. Staining appears to occur in the cytoplasm and the nucleus of the cells. Finally, fluorescein uptake and release are likely to occur through active transports mechanisms.
16
Zorlutuna, Pinar. "Cornea Engineering On Biodegradable Polyesters". Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/3/12605779/index.pdf.
Pełny tekst źródłaStreszczenie:
ABSTRACT
CORNEA ENGINEERING
ON
BIODEGRADABLE POLYESTERS
Zorlutuna, Pinar
M. Sc., Department of Biotechnology
Supervisor: Prof. Vasif Hasirci
Co-Supervisor: Asst. Prof. AySen Tezcaner
January 2005, 66 pages
Cornea is the outermost layer of the eye and has an important role in vision. Damage of cornea due to injuries or infections could lead to blindness lowering the quality of life of the patient severely. In such cases, transplantation or artificial corneas have been used for treatment but both had drawbacks. The novel approach for corneal replacements is the tissue engineering of the cornea, a promising method which would be free of these drawbacks, if successful.
In this study, carriers for tissue engineering of the cornea were designed and tested in vitro. Blends of biodegradable and biocompatible polyesters of natural (PHBV8) and synthetic (PLLA) origin were used to construct these carriers. For the epithelial layer of the cornea, PLLA-PHBV8 micropatterned films were prepared with solvent casting and seeded with D407 (retinal pigment epithelial) cells. In order to achieve proper cell growth, the films were coated with fibronectin. For the stromal layer of the cornea, highly porous foams of PLLA-PHBV8 were prepared by lyophilization and seeded with 3T3 cells (fibroblasts). A new approach was developed to create a combination of the film and the foam to obtain a surface patterned, 3 dimensional cell carrier. These carriers were seeded with Saos-2 cells (osteosarcoma cells) in the preliminary optimization studies and with D407 and 3T3 cells in further studies. The cell numbers on the carriers were quantified by using MTS assay (non-radioactive cell proliferation assay) and the cell proliferation on polymeric carriers was significantly higher than that of control (Tissue culture polystyrene) by the day 14. Characterization of these cells and the carrier was done using a variety of microscopic methods. The micrographs showed that the foam had a highly porous structure and the pores were interconnected. 3T3 cells were found to be distributed quite homogeneously at the seeding site, but due to the high thickness of the foam, the cells could not sufficiently populate the core (central parts of the foam) during the given incubation time. The micropatterned film allowed multilayer formation of D407 cells. The functionality of the cells seeded on the carriers was examined by immunohistochemistry. These analyses proved that the cells retained their phenotype during culturing. D407 cells formed tight junctions characteristic of epithelial cells, and 3T3 cells deposited collagen type I into the foams. Based on the results, it can be concluded that the 3-D PLLA-PHBV8 construct with surface patterns have a serious potential for use as a tissue engineering carrier for the reconstruction of the cornea.
Key words: Tissue engineering, cornea, polymeric carrier, biodegradable, polyester.
17
Cooper, Leanne Jane. "Tissue engineering of the cornea". Thesis, Lancaster University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.421611.
Pełny tekst źródła
18
Shaw, Alyra J. B. "Eyelid pressure on the cornea". Thesis, Queensland University of Technology, 2009. https://eprints.qut.edu.au/31239/1/Alyra_Shaw_Thesis.pdf.
Pełny tekst źródłaStreszczenie:
The eyelids play an important role in lubricating and protecting the surface of the eye. Each blink serves to spread fresh tears, remove debris and replenish the smooth optical surface of the eye. Yet little is known about how the eyelids contact the ocular surface and what pressure distribution exists between the eyelids and cornea. As the principal refractive component of the eye, the cornea is a major element of the eye’s optics. The optical properties of the cornea are known to be susceptible to the pressure exerted by the eyelids. Abnormal eyelids, due to disease, have altered pressure on the ocular surface due to changes in the shape, thickness or position of the eyelids. Normal eyelids also cause corneal distortions that are most often noticed when they are resting closer to the corneal centre (for example during reading). There were many reports of monocular diplopia after reading due to corneal distortion, but prior to videokeratoscopes these localised changes could not be measured. This thesis has measured the influence of eyelid pressure on the cornea after short-term near tasks and techniques were developed to quantify eyelid pressure and its distribution. The profile of the wave-like eyelid-induced corneal changes and the refractive effects of these distortions were investigated. Corneal topography changes due to both the upper and lower eyelids were measured for four tasks involving two angles of vertical downward gaze (20° and 40°) and two near work tasks (reading and steady fixation). After examining the depth and shape of the corneal changes, conclusions were reached regarding the magnitude and distribution of upper and lower eyelid pressure for these task conditions. The degree of downward gaze appears to alter the upper eyelid pressure on the cornea, with deeper changes occurring after greater angles of downward gaze. Although the lower eyelid was further from the corneal centre in large angles of downward gaze, its effect on the cornea was greater than that of the upper eyelid. Eyelid tilt, curvature, and position were found to be influential in the magnitude of eyelid-induced corneal changes. Refractively these corneal changes are clinically and optically significant with mean spherical and astigmatic changes of about 0.25 D after only 15 minutes of downward gaze (40° reading and steady fixation conditions). Due to the magnitude of these changes, eyelid pressure in downward gaze offers a possible explanation for some of the day-to-day variation observed in refraction. Considering the magnitude of these changes and previous work on their regression, it is recommended that sustained tasks performed in downward gaze should be avoided for at least 30 minutes before corneal and refractive assessment requiring high accuracy. Novel procedures were developed to use a thin (0.17 mm) tactile piezoresistive pressure sensor mounted on a rigid contact lens to measure eyelid pressure. A hydrostatic calibration system was constructed to convert raw digital output of the sensors to actual pressure units. Conditioning the sensor prior to use regulated the measurement response and sensor output was found to stabilise about 10 seconds after loading. The influences of various external factors on sensor output were studied. While the sensor output drifted slightly over several hours, it was not significant over the measurement time of 30 seconds used for eyelid pressure, as long as the length of the calibration and measurement recordings were matched. The error associated with calibrating at room temperature but measuring at ocular surface temperature led to a very small overestimation of pressure. To optimally position the sensor-contact lens combination under the eyelid margin, an in vivo measurement apparatus was constructed. Using this system, eyelid pressure increases were observed when the upper eyelid was placed on the sensor and a significant increase was apparent when the eyelid pressure was increased by pulling the upper eyelid tighter against the eye. For a group of young adult subjects, upper eyelid pressure was measured using this piezoresistive sensor system. Three models of contact between the eyelid and ocular surface were used to calibrate the pressure readings. The first model assumed contact between the eyelid and pressure sensor over more than the pressure cell width of 1.14 mm. Using thin pressure sensitive carbon paper placed under the eyelid, a contact imprint was measured and this width used for the second model of contact. Lastly as Marx’s line has been implicated as the region of contact with the ocular surface, its width was measured and used as the region of contact for the third model. The mean eyelid pressures calculated using these three models for the group of young subjects were 3.8 ± 0.7 mmHg (whole cell), 8.0 ± 3.4 mmHg (imprint width) and 55 ± 26 mmHg (Marx’s line). The carbon imprints using Pressurex-micro confirmed previous suggestions that a band of the eyelid margin has primary contact with the ocular surface and provided the best estimate of the contact region and hence eyelid pressure. Although it is difficult to directly compare the results with previous eyelid pressure measurement attempts, the eyelid pressure calculated using this model was slightly higher than previous manometer measurements but showed good agreement with the eyelid force estimated using an eyelid tensiometer. The work described in this thesis has shown that the eyelids have a significant influence on corneal shape, even after short-term tasks (15 minutes). Instrumentation was developed using piezoresistive sensors to measure eyelid pressure. Measurements for the upper eyelid combined with estimates of the contact region between the cornea and the eyelid enabled quantification of the upper eyelid pressure for a group of young adult subjects. These techniques will allow further investigation of the interaction between the eyelids and the surface of the eye.
19
Moreira, Ana Rita Lopes. "Sequestro corneal felino : estudo retrospetivo". Master's thesis, Universidade de Lisboa. Faculdade de Medicina Veterinária, 2015. http://hdl.handle.net/10400.5/9655.
Pełny tekst źródłaStreszczenie:
Dissertação de Mestrado Integrado em Medicina VeterináriaO sequestro corneal felino é uma doença comum da córnea do gato. Este estudo retrospetivo avalia as lesões oculares, fatores de risco, protocolos e sucesso terapêuticos em 43 gatos. Foi revista a história clínica de 43 casos de sequestro corneal felino apresentados no Hospital Escolar da Faculdade de Medicina Veterinária da Universidade de Lisboa. Todos os pacientes foram sujeitos a um exame oftálmico completo e a um tratamento médico ou cirúrgico. Foi realizada a análise dos dados recorrendo a estatística descritiva. A população em estudo inclui 51,2% fêmeas e 48,8% machos, pelo que não houve predisposição de género. Os pacientes tinham idades compreendidas entre os 3 meses e os 13 anos, com uma média de 4,39 ± 3,47 anos. Relativamente às raças afetadas, 69,8% dos pacientes eram Persas, 23,3% Europeus Comuns, 2,3% Siameses, 2,3% British Shorthair e 2,3% Floresta da Noruega. Em 25,6% dos animais estava presente entrópion e 11,6% foram diagnosticados com herpesvírus felino através de PCR. Adicionalmente, 53,5% dos pacientes foram medicados antes de serem apresentados à consulta de oftalmologia, 30,4% dos quais com corticoesteróide tópico e 8,7% foram submetidos a queratectomia em rede. Após a consulta os pacientes foram submetidos a tratamento médico ou cirúrgico. O tratamento farmacológico foi realizado em 41,5% dos animais, mas o sucesso terapêutico foi de apenas 62,5%. Adicionalmente, 51,2% dos animais foram sujeitos a queratectomia superficial, associada a um flap da membrana nictitante ou a um transplante conjuntival pedicular nos casos em que a lesão ocupava mais de metade da espessura da córnea, com uma eficácia de 100%. Em 7,3% dos pacientes o sequestro encontrava-se quase destacado, pelo que foi removido manualmente, com uma taxa de sucesso de 66,7%. Os fatores de risco identificados na população em estudo foram entrópion, infeção por herpesvírus felino, administração prévia de corticosteróides tópicos e realização de queratectomia em rede. O tratamento mais eficaz neste estudo foi o cirúrgico, pelo que este deve ser considerado nos casos não responsivos ao tratamento farmacológico e nos sequestros mais profundos.
ABSTRACT - FELINE CORNEAL SEQUESTRA: RESTROSPECTIVE STUDY - Feline corneal sequestrum is a common condition of the feline cornea. This retrospective study evaluates ocular lesions, risk factors, treatment protocols and outcome in 43 cats. The medical records of 43 cases of feline corneal sequestra that presented to the Teaching Hospital from 2001 to 2014 were reviewed. All patients underwent complete ophthalmic examination and were subjected to surgery or medical treatment. Descriptive statistics was done. The study population comprised 51,2% females and 48,8% males, so there was no gender predisposition. The patients were aged between 3 months and 13 years, median 4,39 ± 3,47 years. Concerning affected breeds, 69,8% of the patients were Persian, 23,3% Domestic Shorthair, 2,3% Siamese, 2,3% British Shorthair and 2,3% Norwegian Forest. Entropion was present in 25,6% of the animals and 11,6% had a positive PCR for feline herpesvirus. Furthermore, 53,5% of the population was being medicated before presenting to ophthalmology consultation, 30,4% of which were being given topical corticosteroids and 8,7% were previously submitted to grid keratotomy. The animals were prescribed medical or surgical treatment. The pharmacological treatment was used in 41,5% of the patients, but the success rate was merely 62,5%. Additionally, 51,2% of the animals were submitted to superficial keratectomy associated with a nictitans flap or a pedicle conjunctival graft if the corneal lesion was deeper, with 100% effectiveness. In 7,3% of the patients the sequestrum was almost detached, being removed manually, this technique being 66,7% effective. The risk factors identified in the population were entropion, herpesvirus infection, previous topical corticosteroid administration and previous grid keratotomy. The most successful treatment in our studied population was surgery and it should be considered in non-responsive cases and deeper sequestra.
20
Yang, Juan. "Universal corneal epithelial-like cells derived from human embryonic stem cells in a defined, xeno-free, and albumin-free condition for cellularization of a corneal scaffold". Thesis, University of Macau, 2018. http://umaclib3.umac.mo/record=b3953938.
Pełny tekst źródła
21
Misson, Gary P. "Birefringent properties of the human cornea in vivo : towards a new model of corneal structure". Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/56247/.
Pełny tekst źródłaStreszczenie:
The fundamental corneal properties of mechanical rigidity, maintenance of curvature and optical transparency result from the specific organisation of collagen fibrils in the corneal stroma. The exact arrangement of stromal collagen is currently unknown but several structural models have been proposed. The purpose of the present study is to investigate inconsistencies between current x‐ray derived structural models of the cornea and optically derived birefringence data. Firstly, the thesis reviews the current understanding of corneal structure, particularly in relation to corneal birefringence. It also reviews and develops the different analytical approaches used to model optical biaxial behaviour, particularly as applied to predict corneal optical phase retardation. The second part develops a novel technique of elliptic polarization biomicroscopy (EPB), enabling study of corneal birefringence in vivo. Using EPB, the pattern of corneal retardation is recorded for a range of human subjects. This dataset is then used to investigate both central and peripheral corneal birefringence as well as the corneal microstructure. A key finding is that the central parts of the cornea exhibit a retardation pattern compatible with a negative biaxial crystal, whereas the peripheral corneal regions do not. Furthermore, within the central regions of the cornea, orthogonal confocal conic fibrillar structures are identified which resemble the analytically derived contours of equal refractive index of an ideal negative biaxial crystal. The third part of this work presents a synthesis of previous published experimental, anatomical and theoretical findings and the experimental results presented in this thesis. Based on these findings, a novel corneal structural model is proposed that comprises overlapping spherical elliptic structural units. Finally, ensuing biomechanical and clinical consequences of the spherical elliptic structural model and of the EPB technique are discussed including their potential diagnostic and surgical applications.
22
Buehren, Tobias F. "Corneal topography, near work and eyelid forces". Thesis, Queensland University of Technology, 2003. https://eprints.qut.edu.au/15882/1/Tobias_Buehren_Thesis.pdf.
Pełny tekst źródłaStreszczenie:
The cornea is the most powerful refractive component of the eye and as such, subtle changes in corneal shape can cause substantial changes in the optical characteristics of the eye. Monocular diplopia has previously been linked to corneal distortion following near work in various studies but has not been investigated in detail. The work reported in this thesis has investigated the optical effects of corneal distortions caused by eyelid forces and demonstrated that several corneal higher and lower order Zernike wavefront aberrations can change following reading.
Measuring subtle changes in corneal topography requires the highest possible instrument accuracy, while software analysis tools should be able to detect and highlight those subtle changes with high reliability. The effect of ocular microfluctuations on the qualitative and quantitative analysis of corneal topography was investigated. A technique was developed to measure tilt, displacement, and cyclotorsion in multiple videokeratographs from the same cornea. This information was used to reposition each videokeratograph according to the average position of a sample of multiple measurements. The corneal topography of ten subjects was measured 20 times each, using videokeratoscopy. The RMSE calculated from difference between single videokeratographs and the average videokeratograph decreased by an average of 24.6 % for the ten subjects' data. The method can improve the precision performance of videokeratoscopy in multiple measurements of corneal topography.
A study was undertaken, to investigate whether there are significant changes in corneal topography during accommodation in normal corneas and corneas that are pathologically thinner due to keratoconus. This was done to eliminate the possibility that changes in corneal aberrations associated with near work could be at least partly due to corneal changes caused by the effects of accommodation. A videokeratoscope was modified to present an accommodation stimulus that was coaxial with the instrument's measurement axis. Six subjects with normal corneas and four subjects with keratoconus were studied. In the initial analysis it was found that a number of the subjects showed significant changes in corneal topography as accommodation changed. However further analysis showed a significant group mean excyclotorsion of the topography maps for both accommodation stimuli compared with the 0 D stimulus. When the excyclotorsion was accounted for, no clear evidence of statistically significant changes in corneal topography as a result of accommodation were found. A small ocular excyclotorsion typically accompanies accommodation and this changes the relative orientation of the topography of the cornea.
To investigate the effects of eyelid pressure on corneal shape and corneal aberrations during reading, twenty young subjects with normal ocular health were recruited. Cornea1 topography of one eye was measured with a videokeratoscope prior to reading and then again after a 60 minute reading task. Twelve of the twenty corneas showed significant changes in central topography immediately following reading. The location of the changes corresponded closely to the position and angle of the subject's eyelids during reading. Within the central region of the cornea there were significant changes in corneal wavefront Zernike coefficients, the root-mean-square error, overall refractive power and astigmatism. The changes observed in corneal topography appear to be directly related to the force exerted by the eyelids during reading. These findings may have important implications for the definition of refractive status and may also aid in the understanding of the relationship between reading and the development of refractive errors.
To study whether corneal distortions after reading significantly differ between refractive error groups, corneal aberrations were measured before and after a period of reading, for a group of ten young progressing myopes and a group of ten young stable emmetropes. The major difference between the two groups was the location and magnitude of the corneal distortions, which had a significantly larger effect on central corneal optics in the myopic group compared to the emmetropic group. A significantly smaller palpebral aperture for the myopic group in the reading gaze position was the cause of this difference.
The experiments described in this thesis have shown that numerous corneal characteristics can change due to eyelid forces during near work. The eye was shown to undergo a small cyclotorsion during higher levels of accommodation. There was a shift in direction of against the rule astigmatism of the cornea following reading and a change was found for primary vertical coma and trefoil. The changes in corneal shape following reading appear to be different in myope versus emmetropic refractive error groups. These findings are important for our understanding of the stability of the refractive error of the eye and could have important implications for refractive error development.
23
Buehren, Tobias F. "Corneal Topography, Near Work and Eyelid Forces". Queensland University of Technology, 2003. http://eprints.qut.edu.au/15882/.
Pełny tekst źródłaStreszczenie:
The cornea is the most powerful refractive component of the eye and as such, subtle changes in corneal shape can cause substantial changes in the optical characteristics of the eye. Monocular diplopia has previously been linked to corneal distortion following near work in various studies but has not been investigated in detail. The work reported in this thesis has investigated the optical effects of corneal distortions caused by eyelid forces and demonstrated that several corneal higher and lower order Zernike wavefront aberrations can change following reading. Measuring subtle changes in corneal topography requires the highest possible instrument accuracy, while software analysis tools should be able to detect and highlight those subtle changes with high reliability. The effect of ocular microfluctuations on the qualitative and quantitative analysis of corneal topography was investigated. A technique was developed to measure tilt, displacement, and cyclotorsion in multiple videokeratographs from the same cornea. This information was used to reposition each videokeratograph according to the average position of a sample of multiple measurements. The corneal topography of ten subjects was measured 20 times each, using videokeratoscopy. The RMSE calculated from difference between single videokeratographs and the average videokeratograph decreased by an average of 24.6 % for the ten subjects' data. The method can improve the precision performance of videokeratoscopy in multiple measurements of corneal topography. A study was undertaken, to investigate whether there are significant changes in corneal topography during accommodation in normal corneas and corneas that are pathologically thinner due to keratoconus. This was done to eliminate the possibility that changes in corneal aberrations associated with near work could be at least partly due to corneal changes caused by the effects of accommodation. A videokeratoscope was modified to present an accommodation stimulus that was coaxial with the instrument's measurement axis. Six subjects with normal corneas and four subjects with keratoconus were studied. In the initial analysis it was found that a number of the subjects showed significant changes in corneal topography as accommodation changed. However further analysis showed a significant group mean excyclotorsion of the topography maps for both accommodation stimuli compared with the 0 D stimulus. When the excyclotorsion was accounted for, no clear evidence of statistically significant changes in corneal topography as a result of accommodation were found. A small ocular excyclotorsion typically accompanies accommodation and this changes the relative orientation of the topography of the cornea. To investigate the effects of eyelid pressure on corneal shape and corneal aberrations during reading, twenty young subjects with normal ocular health were recruited. Cornea1 topography of one eye was measured with a videokeratoscope prior to reading and then again after a 60 minute reading task. Twelve of the twenty corneas showed significant changes in central topography immediately following reading. The location of the changes corresponded closely to the position and angle of the subject's eyelids during reading. Within the central region of the cornea there were significant changes in corneal wavefront Zernike coefficients, the root-mean-square error, overall refractive power and astigmatism. The changes observed in corneal topography appear to be directly related to the force exerted by the eyelids during reading. These findings may have important implications for the definition of refractive status and may also aid in the understanding of the relationship between reading and the development of refractive errors. To study whether corneal distortions after reading significantly differ between refractive error groups, corneal aberrations were measured before and after a period of reading, for a group of ten young progressing myopes and a group of ten young stable emmetropes. The major difference between the two groups was the location and magnitude of the corneal distortions, which had a significantly larger effect on central corneal optics in the myopic group compared to the emmetropic group. A significantly smaller palpebral aperture for the myopic group in the reading gaze position was the cause of this difference. The experiments described in this thesis have shown that numerous corneal characteristics can change due to eyelid forces during near work. The eye was shown to undergo a small cyclotorsion during higher levels of accommodation. There was a shift in direction of against the rule astigmatism of the cornea following reading and a change was found for primary vertical coma and trefoil. The changes in corneal shape following reading appear to be different in myope versus emmetropic refractive error groups. These findings are important for our understanding of the stability of the refractive error of the eye and could have important implications for refractive error development.
24
Ferreira, Gabriel Thadeu Nogueira Martins [UNESP]. "Implante da membrana amniótica criopreservada em associação ou não com transplante de limbo no tratamento de úlceras profundas de córnea em cães". Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/88176.
Pełny tekst źródłaStreszczenie:
Made available in DSpace on 2014-06-11T19:23:09Z (GMT). No. of bitstreams: 0
Previous issue date: 2012-09-04Bitstream added on 2014-06-13T20:50:08Z : No. of bitstreams: 1
ferreira_gtnm_me_araca.pdf: 473953 bytes, checksum: f471fe3fe294467c9ef7539797d814f9 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Objetivo: avaliar a aplicação clínica do implante da membrana amniótica canina criopreservada associada ou não ao transplante de limbo e do recobrimento conjuntival 360º no tratamento de úlceras de córnea profundas. Métodos: quinze cães com ulceração corneal clínica profunda foram alocados em três grupos: GI= recobrimento conjuntival 360º (n=5); GII= implante no bordo da úlcera de membrana amniótica associada ao recobrimento com a terceira pálpebra (n=5) e GIII= implante de membrana amniótica associado ao transplante de limbo córneoescleral autólogo e ao recobrimento com a terceira pálpebra (n=5). Os parâmetros clínicos avaliados foram: blefarospasmo, secreção ocular, vascularização corneal, defeito epitelial, opacificação corneal e qualidade cicatricial em seis momentos (inicial, 1, 3, 7, 15 e 30 dias de posoperatório). Resultados: no GI, não se observou aderência do recobrimento conjuntival 360º na úlcera (n=2), deiscência da sutura do recobrimento conjuntival (n=2), sinéquia anterior (n=2) e intensa quemose (n=1). Nos GII e GIII não foram observadas estas complicações. Os animais do GII e GIII apresentaram cicatrização epitelial no M15 e o GI somente M30 (p<0,05). Com relação aos outros parâmetros oftálmicos, a diferença foi significante entre momentos inicial e final no mesmo grupo (blefarospasmo, secreção ocular, vascularização). A cicatriz corneal apresentouse de maneira mais intensa, densa e desorganizada no GI. Conclusão: o implante da membrana amniótica associada ou não ao transplante de limbo demonstrou ser mais eficaz no tratamento de úlceras profunda de córnea, quando comparado ao recobrimento conjuntival 360º
Purpose: to evaluate the clinical application of implant of the canine cryopreserved amniotic membrane (DMEM plus DMSO 1:1) with or without limbal transplantation and 360° conjunctival flap in the treatment of progressive corneal ulceration. Methods: 15 dogs of the different breeds, males and females, aging four months to four years old with deep corneal ulceration and different clinical progression were divided in two groups: GI=360° conjunctival graft (n=5); GII=implant of amniotic membrane, sutured at the edge of the ulcer with epithelial side facing up, associated with the third eyelid flap (n=5) and GIII=implant of amniotic membrane associated with the transplantation of autologous limbal cornealscleral and covering with the third eyelid flap (n=5). The comparative analysis between groups was: complications of the technique used, blepharospasm, ocular secretion, corneal vascularization, epithelial defect and corneal opacification in six moments (first emergency care, surgery and 3, 7, 15 and 30 days of postoperative). It was used a score scale for subjective quantified of the ocular signs. Results: in GI, it was observed the non adherence of the conjunctival graft to the ulcer (n=2), dehiscence of the suture (n=2), anterior synechia (n=2) and intense chemosis (n=1). In GII and GIII, it was not observed these complications. GII and GIII showed epithelial healing in M15 and GI only M30 (p<0,05). The other ophthalmic parameters, the difference was significant between initial and final in the same group (blepharospasm, ocular discharge, vascularization). The corneal scar presented in a more intense, dense and disorganized in GI. Conclusions: According to the clinical results, the cryopreserved amniotic membrane implant or not in association with transplantation of limbo showed to be more effective in the treatment of deep corneal ulcers compared to the 360° conjunctival flap
25
Ramier, James Charles. "Biomechanics of corneal wound healing /". Online version of thesis, 1992. http://hdl.handle.net/1850/10786.
Pełny tekst źródła
26
Makrynioti, Dimitra. "Variations in corneal morphology across the cornea : a study in normal subjects and contact lens wearers". Thesis, University of Manchester, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492043.
Pełny tekst źródła
27
Colling, Amber J. "A comparison of three methods of measuring central corneal thickness in normal and thinned corneas". The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275058650.
Pełny tekst źródła
28
Lewis, David. "Proteoglycans in normal and diseased cornea". Thesis, Lancaster University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250553.
Pełny tekst źródła
29
Astin, Christine L. K. "Dimensional changes in the ageing cornea". Thesis, Aston University, 2005. http://publications.aston.ac.uk/14565/.
Pełny tekst źródłaStreszczenie:
The study investigated the central and peripheral corneal characteristics of groups of subjects from 20 to 90 years of age to assist the understanding of ageing changes in the cornea, and to see whether relationships between ocular parameters were revealed. After age 45 the corneal horizontal radius of curvature gradually decreased with age. This trend was shown by the Aston University subjects (group B). The effect was very significant for the hospital patients undergoing biometry before cataract extraction operation (group D). Vertical radius of curvature showed a slight decrease with age after age 45, but similar to corneal eccentricity, this showed no significant age effect. Corneal astigmatism progressed from with the rule towards against the rule, particularly after age 60. The shift seemed mainly due to the decreasing horizontal corneal curvature. In biometry no significant age relation was found for axial length, but a significant relation was found between curvature and axial length in the larger group D. Lens thickness showed a very significant relation to age and to axial length, but no significant relation to corneal curvature. Anterior chamber depth showed a very significant relation to age, lens thickness and axial length, but no significant relation to corneal curvature. A significant age effect was found for corneal thickness decreasing with age for the central, nasal and temporal regions of the right eye. Analysis of the biometry results indicated the influence of two major factors. Firstly, the natural growth of the eye in youth, leading to greater values of axial length, radius of corneal curvature, lens thickness and anterior chamber depth. Secondly, the typical ageing changes where the increasing lens thickness caused a reduction in anterior chamber depth.
30
Fullwood, Nigel James. "Ultrastructural studies of cornea and sclera". Thesis, Open University, 1992. http://oro.open.ac.uk/57389/.
Pełny tekst źródłaStreszczenie:
The work of Goodfellow et al., (J. Mol. BioI. 119: 231. 1918) and Sayers et al., (J. Mol. BioI. 160: 593. 1982), was repeated using fresh, equilibrated cornea, confirming their finding that the plot of interfibrillar spacing against liydration is a linear relationship. Intermolecular spacing in cornea, sclera and rat-tail tendon was shown to increase rapidly over the hydration range H=O to H::1, then tan off (physiological hydration is at H=3.2). Intermolecular and interfibrillar spacings rise in unison over the hydration range H=O to H~1, after which virtually all of the water goes between the fibrils. It was found that freezing corneas to 40oC and then thawing had no effect on normally hydrated or dehydrated corneas, but caused damage to swollen corneas. Freezing to ·180°C and thawing resulted in permanent damage to normally hydrated corneas . The changes in intermolecular spacing, D-period spacing, fibril diameter and fibril packing as a result of processing for TEM and SEM have been described. Low temperature embedding in Lowicryl K4M resin produced least disruption in the cornea. The fibril diameter in cornea at normal hydration was established to be 37.4nm±1.4. X-ray data modelling indicates that fibril packing in the cornea is liquid-like, as proposed by Worthington and Inoyue (Int. J. Macromol. 7: 2. 1985). It was shown that the water in the corneal stroma is evenly distributed around the fibrils over the hydration range H=O to H=4. Above H=4 more water is entering the stroma than can be "accounted for if its distribution is uniform. The transmittance of light through the bovine cornea (excluding interference effects), was calculated as T ==::12%. Thus, most of ~he transparency of the cornea must be due to constructive interference as first proposed by Maurice (J. Physiol. 136: 263. 1951). Examination of keratoconus corneas by the the SEM and TEM and showed abnormal epithelial cells, disrupted lamellae, and abnormally arranged proteoglycans. Analysis of X-ray data proved that stromal thinning in keratoconus was not due to closer fibril packing. Also that keratoconus corneas had increased intermolecular spacing, and an abnormal arrangement of proteoglycans along the fibrils. No differences were found between the corneal stroma of normal and myopic chicks. Myopic chick sclera was shown to have more aggrecan proteoglycan which was associated with larger empty spaces, than normal sclera. The fibril attachment sites of the proteoglycans was the same in normal and myopic sclera.
31
Barros, Sobrinho Alexandre Augusto Franchi de. "Propriedades anisotrópicas e refrativas de córneas de coelhos, após implantação de inlays de colágeno tipo I extraído de tendão flexor digital superficial de bovino /". Jaboticabal, 2019. http://hdl.handle.net/11449/181956.
Pełny tekst źródłaStreszczenie:
Orientador: José Luiz LausCoorientador: 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
32
Liu, Lei. "Immunology of herpes simplex keratitis and its treatment by corneal transplantation". Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Online version available for University member only until Sep. 7, 2010, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=33585.
Pełny tekst źródła
33
Musselmann, Kurt. "Developing culture conditions to study keratocyte phenotypes in vitro". [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001726.
Pełny tekst źródła
34
Vrana, Nihal Engin. "Collagen-based Scaffolds For Cornea Tissue Engineering". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607540/index.pdf.
Pełny tekst źródłaStreszczenie:
In this study, collagen based scaffolds were prepared for cornea tissue engineering. Three different cell carriers (rat tail collagen foam, insoluble collagen foam and patterned collagen film) were produced using two different collagen sources. Scaffolds were designed to mimic the unique topographical features of the corneal stroma. A novel crosslinking method was developed to achieve constant foam thickness. All scaffolds were tested with the primary cells of the native corneal stroma, human keratocytes. Although both foams promoted cell growth and penetration, rat tail foams were found to be superior for keratocyte proliferation. Their degradation rates were high enough but did not compromise their structural integrity during testing. Transparency studies with the foams revealed a progressive improvement. Collagen films degraded significantly over a one month periodhowever, the presence of cells increased the tensile strength of the films over a 21 day period to close to that of the native cornea and compensated for the loss of strength due to degradation. The micropatterned films proved to have higher transparency than the unpatterned scaffolds. In this study, it was possible to prepare collagen based micropatterned scaffolds using a silicon wafer and then a silicone template, successively, starting from original designs. The resultant collagen films were able to control cell growth through contact guidance, restricted cells and secreted-ECM within the pattern grooves, resulting in a higher transparency in comparison to unpatterned films. Thus, the tissue engineered constructs revealed a significant potential for use as total artificial corneal substitutes.
35
Shin, Thomas Jungwoog. "The mechanical properties of the human cornea". Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17577.
Pełny tekst źródła
36
Bleshoy, Hans. "Neuropathology and sensitivity in the keratoconic cornea". Thesis, City University London, 1990. http://openaccess.city.ac.uk/7670/.
Pełny tekst źródłaStreszczenie:
Corneal touch threshold (CTT) was investigated by aesthesiometry in patients with keratoconusq with and without contact lens wear. Using a matching control group it was established that CTT was significantly higher for the central corneal position in keratoconus. No difference inCTT was found in four peripheral corneal positions in keratoconic and normal corneas. Central CTT correlated inversely with central corneal curvature and central corneal thickness. Central corneal curvature was the most significant single factor to correlate with central CTT and indicates that CTT increases (sensitivity reduces) as the cornea steepens. Corneal surface irregularityq as measured by mire image distortion, correlated positively with central CTT as did corneal scarring. Central CTT did not show a relationship with duration of the disease nor the visibility of the corneal nerve fibres. Lid margin touch thresholds (LTT) were investigated for the central position on the lower and upper eyelid margins. No statistical differences were found between keratoconic and normal eyes nor between upper and lower eyelid margins. The magnitude of LTT was in the order of that established for the peripheral corneal CTT. Innervation of the human corneal stroma and epithelium was investigated by light and electron microscopy in the central and mid-peripheral positions. All nerve bundles were located in the anterior two thirds of the. corneas. In keratoconic corneas mid-peripheral stromal nerve bundles were disorganised and irregular taking up the shape of the adjacent collagen lamellae. Nerve bundles had a regular oval appearance in the control corneas. In both groups Schwann cell cytoplasm was sparse and of varying degree of electron density; axon varicosities were not uncommon and axon content with respect to organelles were similar. The axon density showed large variation in keratoconic: specimens and averaged more than threefold that of control specimens for stromal and epithelial nerves. The control corneas showed a greater proportion of large diameter stromal axons than in keratoconic corneas. This result was reversed for epithelial axons. The results are discussed with respect to the disease process and influence on tactile sensitivity.
37
Wang, Fan. "UVA/Riboflavin-Induced Apoptosis in Mouse Cornea". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-133626.
Pełny tekst źródłaStreszczenie:
Background: A mouse model of combined UVA/riboflavin irradiation to eliminate stromal cells and other antigen-presenting cells in the cornea provides the basis for a probably low risk of corneal transplantation. Methods: After abrasion of the epithelium, the central corneas of mouse eyes were treated with UVA/riboflavin in vitro. Histological studies of hematoxylin-eosin and immunohistochemical staining with caspase 3 were performed. Dissected mouse corneas were analyzed by Western blot. Results: Apoptotic cells were shown on the central corneal stroma; a cell-free zone was displayed in the cornea. Numbers of dead cells increased according to cultivation time. However, the endothelium survived due to the adjustment of the irradiation dose. Conclusions: A cell-free zone in the stroma of the mouse cornea was produced by UVA/riboflavin irradiation in vitro. The technique makes possible to prevent or reduce immunological reactions and the risk of graft rejection by pretreatment of the donor cornea, ultimately prolonging graft survivalDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
38
Wang, Fan. "UVA/Riboflavin-Induced Apoptosis in Mouse Cornea". Karger, 2008. https://tud.qucosa.de/id/qucosa%3A27521.
Pełny tekst źródłaStreszczenie:
Background: A mouse model of combined UVA/riboflavin irradiation to eliminate stromal cells and other antigen-presenting cells in the cornea provides the basis for a probably low risk of corneal transplantation.
Methods: After abrasion of the epithelium, the central corneas of mouse eyes were treated with UVA/riboflavin in vitro. Histological studies of hematoxylin-eosin and immunohistochemical staining with caspase 3 were performed. Dissected mouse corneas were analyzed by Western blot.
Results: Apoptotic cells were shown on the central corneal stroma; a cell-free zone was displayed in the cornea. Numbers of dead cells increased according to cultivation time. However, the endothelium survived due to the adjustment of the irradiation dose.
Conclusions: A cell-free zone in the stroma of the mouse cornea was produced by UVA/riboflavin irradiation in vitro. The technique makes possible to prevent or reduce immunological reactions and the risk of graft rejection by pretreatment of the donor cornea, ultimately prolonging graft survival.Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
39
BONZANO, CHIARA. "Cornea to the best of our knowledge". Doctoral thesis, Università degli studi di Genova, 2021. http://hdl.handle.net/11567/1045094.
Pełny tekst źródłaStreszczenie:
The cornea has unique features that make it a useful model for regenerative medicine studies. It is an avascular, transparent, densely innervated tissue, and a multitude of pathological changes may impair visual acuity. The first part of this research work aimed to improve knowledge on corneal epithelium's physiology. To study the corneal epithelium, we introduced for the first time the use of a fluorescent labeling to track the migration and proliferation of the epithelial cells. This experimental system paves the way for further research on epithelial cell migration in the normal cornea and a better understanding of corneal epithelium dynamics. The second part of the thesis aimed to understand corneal biomechanics properties better. We evaluated the role of corneal collagen crosslinking, a para surgical technique of corneal tissue strengthening, in treating infectious corneal disease and its correlation with a delayed corneal re-epithelialization. The last part of this translational research focused on a new therapeutical role of autologous serum tears, and the nerve growth factor eye drops in treating ocular surface disorders unresponsive to conventional medical therapy.
40
Silveira, Camila Pinho Balthazar da. "Propriedades birrefringentes e organização macromolecular dos colágenos fibrilares do estroma corneal de cães /". Jaboticabal, 2019. http://hdl.handle.net/11449/181327.
Pełny tekst źródłaStreszczenie:
Orientador: José Luiz LausCoorientador: 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
41
Ribeiro, Alexandre Pinto. "Duração do efeito analgésico e expressão de diferentes metaloproteinases, do colágeno tipo IV e da interleucina-10, em córneas de coelhos tratadas com morfina, após ceratectomia lamelar /". Jaboticabal : [s.n.], 2010. http://hdl.handle.net/11449/101155.
Pełny tekst źródłaStreszczenie:
Orientador: José Luiz LausBanca: Aline Adriana Bolzan
Banca: Cristiane dos Santos Honsho
Banca: Alexandre Lima de Andrade
Banca: Paola Castro Moraes
Resumo: Estudaram-se os efeitos da morfina 1% sobre a reparação corneal, avaliando-se a expressão das metaloproteinases-1, -2, -9, do colágeno tipo IV e da interleucina 10 (IL-10), em coelhos submetidos à ceratectomia lamelar. Dois experimentos foram concebidos, empregando-se 56 animais. No primeiro, 6 coelhos foram tratados com 50μl de morfina 1% (GM), a cada 4 horas, totalizando 4 aplicações diárias. Outros 6 coelhos receberam solução fisiológica (GC) nas mesmas condições adotadas para o GM. Após as ceratectomias, as córneas foram avaliadas até sua epitelização. No segundo, 40 animais foram empregados e as córneas colhidas decorridos 1, 3, 6, 9 e 12 dias das ceratectomias para histologia, imunoistoquímica (MMP-1, MMP-9 e colágeno tipo IV), zimografia (MMP-2 e MMP-9) e ELISA (IL-10). Mais 4 coelhos saudáveis foram utilizados para como controle negativo.O tempo médio de reetitelização não diferiu entre os grupos. Após a ceratectomia, observou-se elevação significativa quanto ao limiar de sensibilidade corneal da 6ª até 96a hora da avaliação. Não se observaram alterações histológicas e quanto ao índice de imunomarcação da MMP-1, -9 e do colágeno do tipo IV entre os grupos estudados . À zimografia, níveis mais elevados de MMP-2 e de MMP-9 foram observados no GM, ao 6º e ao 9º dias após as ceratectomias. Observou-se decréssimo das formas latente e ativa da MMP-9 ao 12º dia. Observou-se, ao 1º dia de avaliação, redução nos níveis de IL-10, comparativamente às córneas saudáveis, mas sem significância estatística entre os grupos, em qualquer dos períodos estudados. O uso local de morfina 1% promoveu analgesia corneal de 4 dias em coelhos submetidos à ceratectomia lamelar e não retardou a epitelização. Elevação do quantitativo da metaloproteinase-1, -2 e -9, em córneas tratadas com morfina 1%, não contraindica seu uso... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This study aimed evaluate the effects of continual topical administration of 1% morphine on corneal analgesia in rabbits subjected to lamellar keratectomy until completion of the corneal wound healing and to assess the expression of matrix metalloproteinases (MMPs)-1, -2 and -9, type IV collagen and interleukin-10 (IL-10) during the treatment. Fifty-six animals were used. In the first experiment, 12 rabbits were divided into two groups, one (n=6) received 50 μl of topical 1% morphine (MG) every 4 hours while the other group (n=6) received 0.9% NaCl instead (CG). After keratectomies, corneas were evaluated until healing. In the second experiment, 40 animals were divided, 4 rabbits of each group were euthanized 1, 3, 6, 9, and 12 days after keratectomy and corneal samples were processed for histology, immunohistochemistry (MMP- 1, -9 and IV collagen), zymography (MMP-2 and -9) and ELISA (IL-10). Other 4 healthy rabbits were used as negative control. In healthy corneas, CTT did not differ significantly before and after morphine instillation. Mean corneal reepithelization rate did not differ between groups. Following keratectomy, CTT increased from the 6h to 96h time points. Scores of leukocyte infiltration, MMP-1, MMP-9 and type IV collagen expression did not differ between groups at any time point. Zymography indicated that levels of the active forms of MMP-2 and MMP-9 increased on days 6 and 9 in the MG. The levels of both latent and active forms of MMP-9, as well as of the latent form of MMP-2 decreased to values close to those of healthy corneas on day 12. IL-10 levels measured on days 1 to 6 were reduced as compared to those of healthy corneal tissue and returned to levels close to those of healthy corneas. Topical application of 1% morphine promoted corneal analgesia for up to 4 days and did not delay corneal reepithelization... (Complete abstract click electronic access below)
Doutor
42
Tsang, K. "Prioritization preferences for corneal transplantation allocation in Hong Kong". Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B31972226.
Pełny tekst źródła
43
Kobashigawa, Karina Kamachi. "Transplante de membrana amniótica com células epiteliais limbais cultivadas em sanduíche : estudos clínicos e de viabilidade em córneas de coelhos /". Jaboticabal, 2018. http://hdl.handle.net/11449/152785.
Pełny tekst źródłaStreszczenie:
Orientador: José Luis LausCoorientador; Marcela Aldrovani Rodrigues
Banca: João Antonio Tadeu Pigatto
Banca: Bruno Watanabe Minto
Banca: Alexandre Lima de Andrade
Banca: Annelise Carla Camplesi dos Santos
Resumo: Visando ao estudo de técnicas para a expansão "ex-vivo" de células destinadas à reconstrução de superfícies oculares com deficiência de células tronco limbais (LSCD), explantes superficiais obtidos do limbo de coelhos foram cultivados sobre membrana amniótica (MA) humana. Dois grupos, diferindo quanto à configuração do sistema de cultivo celular, foram concebidos: G-mono, contendo células epiteliais expandidas sobre a face de uma camada de MA (sistema de cultivo bidimensional), e G-Sand, composto por células "ensanduichadas" entre duas MAs (sistema de cultivo tridimensional). Seis culturas celulares de cada grupo foram avaliadas por imuno-histoquímica quanto à presença de células progenitoras ou indiferenciadas e a de células em proliferação (avaliação pré-transplante), enquanto 21 foram transplantadas para olhos de coelhos com LSCD (n=10). Os olhos receptores de células cultivadas foram clinicamente avaliados, por até 63 dias. A terapia limbal adotada na pesquisa foi autógena. Após avaliações clínicas, os coelhos foram aleatoriamente distribuídos em parcelas e submetidos à eutanásia, para colheita de córneas (dias 14 e 63 após o transplante) que foram avaliadas quanto à morfometria tecidual e à expressão quali-quantitativa de imunomarcadores de indiferenciação celular (fator de transcrição nuclear delta p63), de proliferação celular (antígeno nuclear da proliferação celular, PCNA) e de apoptose (teste de TUNEL). Diferenças com P < 0.05 foram consideradas significativas. As c... (Resumo completo, clicar acesso eletrônico abaixo)
In order to study techniques for the ex vivo expansion of cells for the reconstruction ocular surfaces with limbal stem cell deficiency (LSCD), superficial explants obtained from rabbit limbus were cultured on human amniotic membrane (MA). Two groups, differing in the configuration of the cell culture system, were designed: G-mono, containing expanded epithelial cells on an MA layer (two-dimensional culture system), and G-Sand, composed of cells "sandwiched" between two MAs (three-dimensional culture system). Six cell cultures of each group were processed by immunohistochemistry to identify the presence of progenitor or undifferentiated cells and for proliferating cells (pre-transplant evaluation), and 21 constructs were transplanted onto rabbit eyes with LSCD. The limbal therapy adopted in the research was autogenous and the transplanted eyes were clinically evaluated for up to 63 days. After clinical evaluations, the rabbits were randomly distributed into subgroups and submitted to euthanasia, to harvest corneas (days 14 and 63 post-transplant) that were evaluated for tissue morphometry and the qualitative-quantitative expression of imunnomarkers of indiferentiated cells (delta-p63 transcriptional factor), proliferative cells (proliferating cell nuclear antigen, PCNA) and apoptosis (TUNEL assay). Differences with P <0.05 were considered significant. G-Sand... (Complete abstract click electronic access below)
Doutor
44
Lee, Graham Andrew. "Advances in anterior segment disease / Graham A. Lee". [St. Lucia, Qld.], 2003. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18442.pdf.
Pełny tekst źródła
45
Monteiro, Pedro Miguel Lourenço. "An investigation of tilt, decentration and defocusing errors in videokeratoscopy". Thesis, City University London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.270579.
Pełny tekst źródła
46
Sheng, Huan. "Factors affecting corneal endothelial morphology". Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1141395542.
Pełny tekst źródła
47
Mikolajczak, Janine [Verfasser]. "Veränderungen der Cornea bei neurodegenerativen Erkrankungen / Janine Mikolajczak". Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1148426086/34.
Pełny tekst źródła
48
Scarpa, Fabio. "Automatyc analysis of confocal images of the cornea". Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425676.
Pełny tekst źródłaStreszczenie:
This thesis deals with the automatic analysis of confocal images of the cornea, and with the automatic estimation of clinical parameters.
Corneal diseases and dystrophies (dry-eye, keratoconus, conjunctivitis, herpes keratitis, lattice dystrophy, etc.) affect vision in widely differing ways. Some cause severe visual impairment, while a few cause no vision problems and are discovered during an eye examination. Other dystrophies may cause repeated episodes of pain without leading to permanent loss of vision. Corneal structures are very sensitive to corneal pathologies: nerve fibers, keratocytes, endothelial cells change their morphology. Changes in the morphology of corneal structures are also related to age or prolonged contact lens wear, to surgical interventions on cornea, such as LASIK or PRK, or to transplantation.
In vivo confocal microscopy of the cornea allows to acquire in a rapid and non-invasive way images of the various corneal layers and structures. Analyzing these images has been shown to be quite important to provide clinical information on the cornea state of health. At present, all the analyses of corneal structures are based on manual or semi-automatic methods, and thus the derived clinical parameter values are subjective and error prone.
Thus, a reliable automatic tool for evaluating corneal pathologies is strongly needed. Every automatic method for analyzing the cornea must go through some well defined steps. First, it has to detect the main anatomical structures of the cornea: nerve fibers, keratocytes and endothelial cells. Then it has to quantitatively measure the identified structures. Finally, it has to estimate the parameters of clinical interest.
In this thesis a new algorithm to extract the nerve fibers will be described. Density and morphology of nerve fibers are correlated to corneal pathologies. Then a method for visualizing all corneal structures in the 3D volume will be presented. Keratocytes volumetric density is an important clinical parameter: an algorithm for the automatic recognition of keratocytes in the 3D volume and for the estimation of the volumetric density has been developed. Finally, an algorithm for the automatic endothelial cell contour detection and the estimation of cells density and morphology will be described.
The algorithms presented in this thesis make it possible to conceive a tool to be used for the automatic analyses of the cornea. It will allow to obtain a quantitative and reproducible description of the whole cornea and specific details of the individual structures. It shall provide a diagnostic tool to aid the clinical practice.Questa tesi tratta dell’analisi automatica di immagini confocali della cornea, e della stima automatica di parametri clinici. Malattie e distrofie della cornea (sindrome dell’occhio secco, cheratocono, congiuntiviti, cheratite erpetica, distrofia reticolare, ecc) pregiudicano la visione in molti modi. Alcune causano grave disabilità visiva, mentre poche altre non causano problemi di vista e sono scoperte nel corso di un esame degli occhi. Altre distrofie posso causare ripetuti episodi di dolore senza provocare la perdita permanente della vista. Le strutture della cornea sono molto sensibili alle patologie corneali: le fibre nervose, i cheratociti, le cellule endoteliali modificano la loro morfologia. Cambiamenti nella morfologia delle strutture della cornea sono anche legati all'età o all’uso prolungato di lenti a contatto, ad interventi chirurgici della cornea, come LASIK o PRK, o al trapianto. La microscopia confocale della cornea permette di acquisire in vivo, in modo rapido e non invasivo, immagini dei vari strati della cornea e delle sue strutture. Analizzare queste immagini ha dimostrato essere molto importante per fornire informazioni cliniche sullo stato di salute della cornea. Allo stato attuale, tutte le analisi delle strutture corneali sono basate su metodi manuali o semi-automatici, e quindi i valori dei parametri clinici che ne derivano sono soggettivi e inclini all’errore. Per questi motivi, un affidabile strumento automatico per la valutazione delle patologie della cornea è fortemente raccomandato. Ogni metodo automatico per analizzare la cornea deve passare attraverso alcune fasi ben definite. In primo luogo, deve riuscire ad individuare le principali strutture anatomiche della cornea: fibre nervose, cheratociti e cellule endoteliali. Poi, deve misurare quantitativamente le strutture individuate. Infine, deve stimare i parametri di interesse clinico. In questa tesi, un nuovo algoritmo per estrarre le fibre nervose verrà descritto. Densità e morfologia dei nervi sono correlate a patologie della cornea. Successivamente, sarà presentato un metodo per la visualizzazione di tutte le strutture della cornea nel volume 3D. La densità volumetrica dei cheratociti è un importante parametro clinico: un algoritmo per il riconoscimento automatico dei cheratociti nel volume 3D e per la stima della densità volumetrica è stato sviluppato. Infine, un algoritmo per il riconoscimento automatico dei bordi delle cellule endoteliali e la stima della densità e morfologia cellulare sarà descritto. Gli algoritmi presentati in questa tesi rendono possibile pensare ad uno strumento da utilizzare per l'analisi automatica della cornea. Consentirà di ottenere una stima quantitativa e una descrizione riproducibile di tutta la cornea e dettagli quantitativi delle singole strutture. Potrà essere uno strumento diagnostico di aiuto alla pratica clinica.
49
Hammar, Björn. "Two New Corneal Diseases Characterized by Recurrent Erosions". Doctoral thesis, Linköpings universitet, Oftalmologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17490.
Pełny tekst źródłaStreszczenie:
Recurrent corneal erosions are a common complication of superficial corneal wounds. They most commonly arise following a trauma, in association with various corneal dystrophies, or are idiopathic. The main aim of this thesis was to investigate two hereditary corneal diseases with recurrent erosions in order to find out if they had been described before, and more specifically to describe the clinical picture and the morphological changes, differentiate them from other known autosomal dominant corneal dystrophies with a clinical resemblance, and to exclude genetic linkage to known corneal dystrophies with autosomal-dominant inheritance and a clinical resemblance. The thesis is based on two families of subjects belonging to different phenotypes. The subjects from Småland (Dystrophia Smolandiensis) belonged to a six-generation family, which included 171 individuals of whom 44 were affected individuals, and the family from Hälsingland (Dystrophia Helsinglandica) included sevengenerations of 342 individuals, of whom 84 were affected. The individuals in both families were investigated by collection of medical history through medical records and questionnaires assessing different aspects of the diseases, pedigree analysis, and from clinical examination. Haplotype analysis was used to exclude genetic linkage of both diseases to known autosomal-dominant corneal dystrophies with a clinical resemblance. The morphological changes in Dystrophia Smolandiensis were investigated by examining affected individuals with in-vivo confocal microscopy and/or slit-lamp biomicroscopy, and examining corneal tissue samples using histopathology and immunohistochemistry. In Dystrophia Helsinglandica, the morphological changes were described using in-vivo confocal microscopy and/or slit-lamp biomicroscopy, but also using videokeratography and corneal sensitivity measurement. The main results were the findings of two new corneal disorders with autosomal dominant inheritance, characterized by recurrent corneal erosions. In Dystrophia Smolandiensis the symptoms often started within the first year of life. The number of recurrences per year was highest from the onset and for about 30-40 years, and the duration of recurrence could stretch up to 21 days. The frequency of recurrences was variable in the disease from continuous symptoms to once a year and tended to decrease later in life. The risk of having recurrences did not disappear completely with age. Typical precipitating factors of recurrence were draught and a common cold. About two thirds of the affected individuals responded well to oral vitamin B treatment, but no other therapy has so far been successful. In Dystrophia Smolandiensis development of corneal opacifications or secondary scarring of varying type and degree was seen in about half of the subjects. Opacifications were first noted at the age of about 7 years, but usually first seen at the age of 20-40 years. Corneal grafting was performed in nine individuals, and recurrences were seen in all grafts. The corneal buttons showed epithelial hyperplasia, partial or total loss of Bowman’s layer, and subepithelial fibrosis in the light microscope. The deeper stroma, Descement’s membrane, and endothelium were normal. Confocal microscopy confirmed loss of Bowman’s layer and revealed that the corneal nerves either were normal in their sub-basal plexa or showed signs of regeneration. None of the morphological findings were specific. We believe that the opacifications are reactive corneal changes to repeated erosive events. The onset in Dystrophia Helsinglandica was usually at the age of 4-7 years and late-developing subepithelial fibrosis not significantly affecting visual acuity was seen in all affected individuals over the age of 37 years. The number of recurrences per year was highest from the onset and for about 20-30 years, and the duration of recurrence was usually up to about a week. The frequency of recurrences tended to decrease in the disease with increasing age, but did not cease completely. The precipitating factor of recurrence was typically a minor trauma. No therapy has so far been successful in the family. The corneal changes of affected individuals were classified into different stages from a nearly normal cornea to progressive fairly discrete subepithelial fibrosis of the central cornea. Discrete localized Subepithelial fibrosis in the periphery or mid-periphery (stage I) was the sole finding in 12% of the individuals. A more widespread subepithelial fibrosis, mainly in the mid-periphery, was found in 31% of the individuals (stage II). In stage III, the subepithelial fibrosis engaged the central cornea but did not affect the vision to a significant degree. In late phases of stage III small jellylike corneal irregularities could be seen. We believe that the opacifications are reactive changes to repeated erosive events. In conclusion this thesis describes two new corneal disorders – Dystrophia Smolandiensis and Dystrophia Helsinglandica.
50
Saia, Paula Simone. "Sistema ceratométrico de apoio a suturas na córnea". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-26032008-153951/.
Pełny tekst źródłaStreszczenie:
Um sistema para auxílio à cirurgias oftálmicas foi desenvolvido com o objetivo de se minimizar o astigmatismo induzido devido ao formato irregular da córnea pelo ato de sutura. O sistema projeta 48 pontos de luz no filme lacrimal da córnea, provenientes de LEDs, dispostos num diâmetro precisamente circular. O deslocamento, a dimensão e a deformação da imagem refletida destes pontos luminosos são analisados proporcionando a ceratometria e a circularidade da sutura. O intervalo de medidas do sistema é de 32D - 55D (astigmatismos até 23D podem ser medidos) e um sistema para calibração do sistema foi projetado para manter o sistema calibrado. Esferas de aço de precisão foram submetidas ao sistema e uma correlação de 99% entre as medidas obtidas e os valores dos fabricantes foi obtida. O sistema foi testado em 13 voluntários para avaliação de sua aplicabilidade clínica e comparado a um ceratômetro comercial Topcon OM-4. Os fatores de correlação entre o sistema desenvolvido e o Topcon OM-4, para o astigmatismo, foi de \'R POT.2\' = 0,92, e em relação ao eixo, o fator é \'R POT.2\' = 0,99. O sistema indica que o cirurgião deve obter uma circularidade \'> OU =\' 98% para que astigmatismos acima de 3D não sejam induzidos na sutura.A system for ophthalmic surgery support has been developed in order to minimize the residual astigmatism due to the induced irregular shape of the cornea by corneal suture. The system projects 48 light spots, from LEDs, displayed in a precise circle at the lachrymal film of the examined cornea. The displacement, the size and deformation of the reflected image of these light spots are analyzed providing the keratometry and the circularity of the suture. Measurements in the range of 32D - 55D (up to 23D of astigmatism are possible to be obtained) and a self-calibration system has been designed in order to keep the system calibrated. Steel precision spheres have been submitted to the system and the results show 99% of correlation with the fabricant\'s nominal values. The system has been tested in 13 persons in order to evaluate its clinical applicability and has been compared to a commercial keratometer Topcon OM-4. The correlation factors are 0,92 for the astigmatism and 0.99 for the associated axis. The system indicates that the surgeon should achieve circularity \'> OR =\' 98% in order to do not induce astigmatisms over 3D.