Dissertations / Theses: 'Retina Diseases'

1

Wu, Kathy H. "Histopathological studies of the aging human retina." Thesis, The University of Sydney, 2002. https://hdl.handle.net/2123/27837.

Full text

Abstract:

Age-related macular degeneration (AMD) is the leading cause of untreatable blindness. Its global prevalence continues to increase in relation to aging of the population. Despite the increasing impact of AMD, its pathogenesis remains to be fully defined. Improved therapeutic measures such as photodynamic therapy and pharmacological interventions are being developed for some cases of Wet AMD; however, treatment remains unavailable for the Dry form which accounts for a significant proportion of AMD cases. Neither has any intervention been developed to reduce the incidence of the disease.

APA, Harvard, Vancouver, ISO, and other styles

2

梁欣珮 and Yan-pui Irene Leung. "Potential impact of alzheimer's disease on retina." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42905059.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Chang, Hui. "Oxidative stress in the retina an experimental study in the rat /." Lund : Dept. of Ophthalmology, University Hospital, Lund University, 1994. http://catalog.hathitrust.org/api/volumes/oclc/39725792.html.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Källmark, Fredrik. "Investigations of perimetry and gaze-stability in the healthy and deceased retina /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-561-5/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Bhagavatheeshwaran, Govind. "Magnetic Resonance Imaging of the Rat Retina." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-041608-144837/.

Full text

Abstract:

Thesis (Ph.D.)--Worcester Polytechnic Institute.
Keywords: Mn54-autoradiography, rat retina, manganese enchanced mri, rcs rat, magnetic resonance imaging, retinal degeneration, high-resolution mri, blood volume imaging Includes bibliographical references (leaves 211-226).

APA, Harvard, Vancouver, ISO, and other styles

6

Mellough, Carla Bernadette. "An assessment of the cell replacement capability of immortalised, clonal and primary neural tissues following their intravitreal transplantation into rodent models of selective retinal ganglion cell depletion." University of Western Australia. School of Anatomy and Human Biology, 2005. http://theses.library.uwa.edu.au/adt-WU2005.0101.

Full text

Abstract:

[Truncated abstract] Microenvironmental changes associated with apoptotic neural degeneration may instruct a proportion of newly transplanted donor cells to differentiate towards the fate of the deteriorating host cellular phenotype. In the work described in this thesis, this hypothesis was tested by inducing apoptotic retinal ganglion cell (RGC) death in neonatal and adult rats and mice, and then examining whether intravitreally grafted cells from a range of sources of donor neural tissue became incorporated into these selectively depleted retinae. Donor tissues were: a postnatal murine cerebellar-derived immortalised neural precursor cell line (C17.2); an adult rat hippocampal-derived clonal stem-like line (HCN/GFP); mouse embryonic day 14 (E14) primary dissociated retinal cells (Gt[ROSA]26); and adult mouse ciliary pigmented margin-derived primary neurospheres (Gt[ROSA]26). In neonates, rapid RGC death was induced by removal of the contralateral superior colliculus (SC), and in adults, delayed RGC death was induced by unilateral optic nerve (ON) transection. Some adult hosts received ON transection coupled with an autologous peripheral nerve (PN) graft. Donor cells were injected intravitreally 6-48 h after SC ablation (neonates) or 0, 5, 7 or 14 days after ON injury (adults). Cells were also injected into non-RGC depleted neonatal and adult retinae. At 4 or 8 weeks, transplanted cells were identified, quantified and their differentiation fate within host retinae was assessed. Transplanted male C17.2 cells were identified in host retinae using a Y-chromosome marker and in situ hybridisation, or by their expression of the lacZ reporter gene product Escherichia coli beta-galactosidase (beta-gal) using Xgal histochemistry or a beta-gal antibody. No C17.2 cells were identified in axotomised adult-injected eyes undergoing delayed RGC apoptosis (n = 16). Donor cells were, however, stably integrated within the retina in 29% (15/55) of mice that received C17.2 cell injections 24 h after neonatal SC ablation; 6-31% of surviving cells were found in the RGC layer (GCL). These NSC-like cells were also present in intact retinae, but on average there were fewer cells in GCL. In SC-ablated mice, most grafted cells did not express retinal-specific markers, although occasional donor cells in the GCL were immunopositive for beta-III tubulin (TUJ1), a protein highly iii expressed by, but not specific to, developing RGCs. Targeted rapid RGC depletion thus increased C17.2 cell incorporation into the GCL, but grafted C17.2 cells did not appear to differentiate into an RGC phenotype.

APA, Harvard, Vancouver, ISO, and other styles

7

Zanoni, Diogo Sousa [UNESP]. "Experimental glaucoma model (ischemia and reperfusion): histology, morphometry, protein and gene espression of apoptosis pathway." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/132013.

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

8

Zanoni, Diogo Sousa. "Experimental glaucoma model (ischemia and reperfusion) : histology, morphometry, protein and gene espression of apoptosis pathway /." Botucatu, 2015. http://hdl.handle.net/11449/132013.

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

9

Frida, Jonsson. "Underlying genetic mechanisms of hereditary dystrophies in retina and cornea." Doctoral thesis, Umeå universitet, Institutionen för medicinsk biovetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130538.

Full text

Abstract:

Inherited retinal and corneal dystrophies represent a group of disorders with great genetic heterogeneity. Over 250 genes are associated with retinal diseases and 16 genes are causative of corneal dystrophies. This thesis is focused on finding the genetic causes of corneal dystrophy, Leber congenital amaurosis (LCA), Stargardt disease and retinitis pigmentosa in families from northern Sweden. By whole exome sequencing a novel mutation, c.2816C>T, p.Thr939Ile, in Collagen Type XVII, Alpha 1 chain, COL17A1, gene was identified in several families with epithelial recurrent erosion dystrophy (ERED). We showed that the COL17A1 protein is expressed in the basement membrane of the cornea, explaining the mutation involvement in the corneal symptoms. We could link all the families in this study to a couple born in the late 1700s confirming a founder mutation in northern Sweden. Our finding highlights role of COL17A1 in ERED and suggests screening of this gene in patients with similar phenotype worldwide. Furthermore the genetic causes in several retinal degenerations were identified. In one family with two recessive disorders, LCA and Stargardt disease, a novel stop mutation, c.2557C>T, p.Gln853Stop, was detected in all LCA patients. In the Stargardt patients two intronic variants, the novel c.4773+3A>G and c.5461-10T>C, were detected in the ABCA4 gene. One individual was homozygous for the known variant c.5461-10T>C and the other one was compound heterozygote with both variants present. Both variants, c.4773+3A>G and c.5461-10T>C caused exon skipping in HEK293T cells demonstrated by in vitro splice assay, proving their pathogenicity in Stargardt disease. Finally, in recessive retinitis pigmentosa, Bothnia Dystrophy (BD), we identified a second mutation in the RLBP1 gene, c.677T>A, p.Met226Lys. Thus, BD is caused not only by common c.700C>T variant but also by homozygosity of c.677T>A or compound heterozygosity. Notably, known variant, c.40C>T, p.R14W in the CAIV gene associated with a dominant retinal dystrophy RP17 was detected in one of the compound BD heterozygote and his unaffected mother. This variant appears to be a benign variant in the population of northern Sweden. In conclusion, novel genetic causes of retinal dystrophies in northern Sweden were found demonstrating the heterogeneity and complexity of retinal diseases. Identification of the genetic defect in COL17A1 in the corneal dystrophy contributes to understanding ERED pathogenesis and encourages refinement of IC3D classification. Our results provide valuable information for future molecular testing and genetic counselling of the families.

APA, Harvard, Vancouver, ISO, and other styles

10

López, Begines Santiago. "Unveiling novel components of the protein complex responsible for cGMP synthesis in retinal photoreceptors: role in cell physiology and disease." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/461890.

Full text

Abstract:

In photoreceptor cells of the retina, light triggers a protein G-mediated enzymatic cascade that leads to hydrolysis of cGMP. The drop in cGMP levels causes the closure of cGMP-channel at the plasma membrane, decreasing the influx of cations, mainly Na+ and Ca2+, hyperpolarizing the cell. This hyperpolarization decreases the rate of neurotransmitter release at the synaptic terminal. Photoreceptor cells must recover the darkness equilibrium and adapt their light sensitivity to the wide range of light intensities present in the natural world. Genetic defects at both activation and termination cascades leads to inherited retinal dystrophies. The cGMP levels are restored to darkness equilibrium by new synthesis by the complex formed by a membrane form of guanylate cyclase (RetGC) which is bound to a couple of proteins that confers it calcium sensitivity, Guanylate Cyclase Activating Proteins (GCAP1 and GCAP2). RetGC activity is stimulated by the drop of Ca2+ concentration because of close of cGMP-channels. There is a feedback loop between cGMP and Ca2+ that has a fundamental role in the processes of termination of light response and light adaptation. RetGC1 is responsible for cGMP synthesis in rods and cones. Mutations of genes involved in the cGMP synthesis complex have been linked to autosomal dominant inherited retinal dystrophies, both retinitis pigmentosa (adRP) as Leber’s congenital amaurosis (LCA) The regulation of RetGC by GCAPs proteins has been extensively studied in vitro, at biochemical and structural levels. However, many relevant aspects of regulation and trafficking of this complex in vivo remains unknown. By subretinal electroporation, we have analyzed the molecular determinants of subcellular distribution of GCAPs. We have determined that the complex between RetGC1 and GCAP1 is assembled in the inner segment and then transported to the outer segment, playing a determinant role the myristoylation of GCAP1 and the binding of GCAP1 to the cyclase. On the other hand, phosphorylation plays an essential role in subcellular distribution of GCAP2, and failures in subcellular localization of GCAP2 could contribute to explain the pathophysiology of the human G157R mutation linked to adRP. We here report a proteomic approach to identify novel interactors of Guanylate Cyclase Activating Protein 1 (GCAP1) that led to the unexpected discovery of inosine monophosphate dehydrogenase 1 (IMPDH1) interaction with retinal guanylate cyclase 1 (RetGC1). IMPDH1 is the rate-limiting step in de novo GTP synthesis, and mutations in impdh1 gene have been associated to adRP and LCA. We reveal an unanticipated direct interaction between IMPDH1 and RetGC1 at photoreceptor outer segments where phototransduction takes place. The interaction involves the dimerization and catalytic domains of RetGC1, and is significantly affected by IMPDH1 mutations associated to blindness. This finding links de novo GTP synthesis to GTP conversion to cGMP, bridging blindness-causative genes so far considered unrelated and creating a new scenario for the development of therapeutic strategies. By bridging distinct blindness-causative genes in a common biochemical pathway, we here contribute to reduce the apparent complexity of inherited retinal dystrophies grouping them on base common metabolic pathways. The main aim of this strategy of grouping genes on base of their function is to identify “hubs” of cell damage. We also have characterized the interaction between RetGC1 and Creatine kinase B, which could be supplying locally the ATP needed to maintain the catalytic activity in cones. This work aid to understanding about regulation and trafficking of RetGC/GCAPs complex, as well as the interplaying between the cGMP synthesis complex and de novo GTP synthesis, opening a new conceptual framework for pharmacological treatment of diseases that trigger changes in intracellular levels of cGMP, which in a prolonged way affect to cell survival, leading to inherited blindness.
En fotorreceptores de retina, la respuesta a luz desencadena la hidrólisis del cGMP. La síntesis de cGMP recae en el complejo formado por una forma de membrana de la guanilato ciclasa (RetGC1 y RetGC2) y unas proteínas que le confieren sensibilidad a calcio (Guanylate Cyclase Activating Proteins GCAP1 y GCAP2). Mutaciones en los genes que codifican para las proteínas integrantes de este complejo han sido ligadas distrofias hereditarias de retina autosómicas dominantes. La regulación de este complejo ha sido extensamente estudiada in vitro, sin embargo, muchos aspectos relacionados con este complejo en el entorno de la célula viva se desconocen. Determinamos mediante electroporación subretinal que el ensamblaje del complejo formado por RetGC1 y GCAP1 precede a su transporte hacia el segmento externo y tanto la miristoilación como la unión a la ciclasa por parte de GCAP1 son necesarias para su transporte. Por otro lado, la fosforilación juega un papel clave en la distribución celular de GCAP2, y fallos en la localización de GCAP2 podrían contribuir a explicar la patofisiología de la mutación hG157R ligada a retinosis pigmentaria autosómica dominante. Mediante una aproximación proteómica para identificar nuevos interactores de GCAP1, hemos caracterizado la interacción directa entre la guanilato ciclasa y la inosina monofosfato deshidrogenasa (IMPDH1), la enzima responsable del paso limitante en la síntesis de novo de GTP. Mutaciones en el gen impdh1 se han asociado a distrofias hereditarias de retina autosómicas dominantes. Ambas proteínas se localizan en el compartimento sensorial, interaccionan en el orden micromolar, involucrando a los dominios de dimerización y catalítico de RetGC1 y la interacción se afecta significativamente por los mutantes asociados a ceguera en IMPDH1. Además también se ha caracterizado la interacción de RetGC con la Creatina quinasa B (CKB), la cual podría está proporcionando el ATP local necesario para mantener la actividad catalítica específicamente en conos. Este trabajo arroja luz sobre la regulación y transporte del complejo RetGC/GCAPs, así como la interconexión entre los complejos de síntesis de cGMP y síntesis de novo de GTP, integrando genes asociados a enfermedad en base a su implicación en procesos metabólicos comunes, abriendo un nuevo escenario para el tratamiento farmacológico de enfermedades que provoquen cambios en los niveles de cGMP intracelulares.

APA, Harvard, Vancouver, ISO, and other styles

11

Jang, Wai-chi, and 張慧芝. "Responses of retinal pigment epithelial cells to anoxic/hypoxic stressafter hypoxia-inducible factor-1-alpha down-regulation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43571980.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Mustafi, Debarshi. "Genetic Signatures of the Retina in Health and Disease." Case Western Reserve University School of Graduate Studies / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=case1372776307.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Kwok, Kwan-ho Alvin, and 郭坤豪. "Dye assisted macular epiretinal membrane surgery." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B32016906.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

McGill, Trevor, and University of Lethbridge Faculty of Arts and Science. "Functionally non-adaptive retinal plasticity in rat models of human retinal degenerative disease." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2008, 2008. http://hdl.handle.net/10133/726.

Full text

Abstract:

The established model used for evaluating potential therapies for retinal disease has significant limitations. A new model is proposed to account for these limitations: the visual adaptation model. The visual adaptation model was developed to provide a novel approach for testing potential treatments for retinal disease, and the work in this thesis provides empirical support for this model. Specifically, we evaluated two potential therapies for retinal degenerative disease and examined their effects on vision and retinal anatomy. In addition, the profile of retinal reorganization and its functional correlates were examined in RCS rats and transgenic rats which express a rhodopsin mutation; however, immunohistological work targeted one specific line (S334ter-4). Collectively, these studies provide evidence that supports the retinal adaptation model. These studies also provide a novel view of retinal and visual function in retinal disease which should be considered when evaluating treatments involving retinal degeneration.
xvii, 205 leaves : ill. ; 29 cm. --

APA, Harvard, Vancouver, ISO, and other styles

15

Kukhtar, Kukhtar Dmytro. "CRISPR-Cas9 to model retinitis pigmentosa caused by mutations in splicing factors in C. Elegans." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/672361.

Full text

Abstract:

Retinitis pigmentosa (RP) is a rare, heterogenic, and hereditary disease that produces gradual loss of the visual field and can cause blindness. Mutations causing RP are still unknown in about 50% of the cases. By CRISPR-Cas9, we mimicked a few splicing-related RP mutations (s-adRP) in PRPF8/prp-8 and SRNPN200/snpr-200 that were used for drug screens, identify potential disease modifiers, investigate mechanisms of the disease, and work on a system to provide functional information for gene variants. One of the alleles generated, displaying an overt phenotype, was used in a small-scale drug screen to identify small molecules capable of alleviating the phenotype. Unexpectedly, we found an FDA-approved drug having a detrimental effect on some of the s-adRP mutant strains. Since RP onset and progression are highly variable due to environmental or genetic modifiers, C. elegans could help RP prognosis by identifying such modifiers. We performed a small-scale RNAi screen on RP mutants with no overt phenotypes and found genetic interactions with other splicing- related genes: isy-1/ISY1, mog-2/SNRPA1, and cyn-15/PPWD1. Thus, secondary mutations in these genetic interactors could act as modifiers of the course of the disease. The mechanism by which s-adRP mutations selectively cause retinal deterioration is unknown. We detected some hints of genome instability in s-adRP mutants, which might explain the degenerative nature of the disease. We are taking steps towards establishing C. elegans as an RP diagnosis model by evaluating the functional impact of potential RP mutations, or variants of uncertain significance (VUS), in worms. For that purpose, we set a panel of features associated with s-adRP mutations, including a genetic interaction with a CRISPR-edited Slow Polymerase II mutant (ama-1(cer135[R743H])), mortal germline, or aberrant splicing events at specific transcripts. We partially humanized the sequence encoding the splicing factors prp-3 in the endogenous locus to investigate if such humanization is beneficial for functional studies of VUS. Therefore, our RP research line demonstrates the value of C. elegans for investigating rare diseases and for providing valuable information in search of drugs, diagnosis, and prognosis.

APA, Harvard, Vancouver, ISO, and other styles

16

Muir, Eric R. "Magnetic resonance imaging of retinal physiology and anatomy in mice." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37268.

Full text

Abstract:

MRI can provide anatomical, functional, and physiological images at relatively high spatial resolution and is non-invasive and does not have depth limitation. However, the application of MRI to study the retina is difficult due to the very small size of the retina. This thesis details the development of MRI methods to image blood flow (BF), anatomy, and function of the retina and choroid, and their application to two diseases of the retina: diabetic retinopathy and retinal degeneration. A unique continuous arterial spin labeling technique was developed to image BF in mice and tested by imaging cerebral BF. This method was then applied to image layer-specific BF of the retina and choroid in mice, and to acquire BF functional MRI of the retina and choroid in response to hypoxic challenge. Additionally blood oxygen level dependent functional MRI of the mouse retina and choroid in response to hypoxic challenge was obtained using a balanced steady state free precession sequence which provides fast acquisition, has high signal to noise ratio, and does not have geometric distortion or signal dropout artifacts. In a mouse model of diabetic retinopathy, MRI detected reduced retinal BF in diabetic animals. Visual function in the diabetic mice, as determined by psychophysical tests, was also reduced. Finally, in a mouse model of retinal degeneration, BF and anatomical MRI detected reductions of retinal BF and the thickness of the retina. The studies detailed in this thesis demonstrate the feasibility of layer-specific MRI to study BF, anatomy, and function, in the mouse retina. Further, these methods were shown to provide a novel means of studying animal models of retinal disease in vivo.

APA, Harvard, Vancouver, ISO, and other styles

17

McGill, Trevor, and University of Lethbridge Faculty of Arts and Science. "Cell therapy limits loss of vision in an animal model of retinal degenerative disease." Thesis, Lethbridge, AB : University of Lethbridge, Faculty of Arts and Science, 2004, 2004. http://hdl.handle.net/10133/274.

Full text

Abstract:

The Royal College of Surgeons (RCS) rat was used as a model of human retinal degenerative disease, and for studying the efficacy of cell transplanation treatments. In order to characterize the spatial vision of the RCS strain, the visual acutiy and contrast sensitivity of adult non-dystrophic RCS rats was measured. The acuity and contrast sensitivity of these rats was normal. The acuity of dystrophic RCS rats was alos characterized to determine how photoreceptor degeneration affects vision. These rats progressively lost visual acuity from one month of age until elevn months of age when they were judged to be blind. The degeneration of vision in these animals was more protacted than would be predicted from previous anatomical and electrophysiological measures. Subretinal transplantation of human-derived Retinal Pigment Epithelial (RPE) cells and human Schwann cells into the dystrophic RCS rat significantly delayed the loss of visual acuity. These studies show that cell transplantation may be a viable method of limiting loss of vision in humans with retinal degenerative blinding diseases.
vii, 77 leaves ; 29 cm.

APA, Harvard, Vancouver, ISO, and other styles

18

Campello, Blasco Laura. "Expression in the mammalian retina of genes and proteins associated with Parkinson and other neurodegenerative diseases." Doctoral thesis, Universidad de Alicante, 2015. http://hdl.handle.net/10045/85191.

Full text

Abstract:

La enfermedad de Parkinson es el segundo trastorno neurodegenerativo más común de nuestra sociedad tras el de Alzheimer. Se caracteriza por una disminución de los niveles del neurotransmisor dopamina asociada a la muerte de las neuronas dopaminérgicas en la substantia nigra del mesencéfalo, proceso que sucede de forma análoga en las células dopaminérgicas de la retina, el subtipo de células amacrinas A18. En consecuencia, además de las múltiples deficiencias motoras y cognitivas que conlleva esta enfermedad, también se han observado alteraciones, a nivel morfológico y fisiológico, en la retina de enfermos de Parkinson y animales modelo de esta enfermedad. Dichas alteraciones incluyen deficiencias en la agudeza visual, sensibilidad al contraste, percepción del color y adaptación a la oscuridad, así como en la detección del movimiento. Sin embargo, se hace necesario esclarecer los mecanismos moleculares subyacentes a esta patología en la retina con el fin de facilitar el diagnóstico molecular y la búsqueda de nuevas dianas terapéuticas. En esta Tesis Doctoral se ha analizado la expresión génica y el patrón de distribución en la retina de distintos mamíferos, desde roedores hasta la especie humana, de dos proteínas de elevada relevancia en la enfermedad de Parkinson, denominadas parkina y UCH-L1, dos importantes componentes del sistema ubicuitina-proteasoma, implicado en la homeostasis proteica celular. En este contexto, se han revisado en profundidad los componentes que integran este sistema en la retina, junto a su papel en el desarrollo y función de este tejido en condiciones fisiológicas y sus alteraciones en condiciones patológicas. Por otra parte, se ha estudiado el patrón de procesamiento ('splicing') alternativo del ARNm del gen PARK2, el cual codifica la proteína parkina, en la retina de mamíferos en condiciones fisiológicas, proceso cuya desregulación está implicada en el desarrollo y progresión de diversas patologías que afectan a la retina, incluida la enfermedad de Parkinson. Adicionalmente, se han investigado las alteraciones a nivel proteico en la retina de monos parkinsonianos tratados con el compuesto neurotóxico MPTP, mediante técnicas de proteómica. Finalmente, se han catalogado y cuantificado todos los genes expresados en la retina adulta humana mediante secuenciación masiva del transcriptoma (RNA-Seq), con especial énfasis en aquellos relacionados con enfermedades neurodegenerativas que afectan a la retina. En conclusión, en esta Tesis Doctoral se ha abordado mediante diferentes aproximaciones experimentales en la retina de mamíferos el estudio de la expresión de los genes y proteínas relacionados con enfermedades neurodegenerativas del sistema nervioso central que cursan con alteraciones en la estructura y función de la retina.

APA, Harvard, Vancouver, ISO, and other styles

19

Fernández, Sánchez Laura. "Protective effects of antiapoptotics and antioxidants in the treatment of retinal neurodegenerative diseases." Doctoral thesis, Universidad de Alicante, 2015. http://hdl.handle.net/10045/46846.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Read, Russell W. "The role of complement in experimental autoimmune uveitis." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2007p/read.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Devarajan, Gayathri. "Activation of microglia in ageing retina and in age-related macular degeneration and their role in RPE degeneration." Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=192261.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Kight, Amanda C. "Optimization of a technique for phosphorescence lifetime imaging of oxygen tension in the mouse retina." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0430102-115119.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Kezic, Jelena Marie. "A study of the monocyte-derived cell populations of the uveal tract and retina in homeostatic conditions and during the early stages of ocular autoimmune disease." University of Western Australia. School of Anatomy and Human Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2009.0084.

Full text

Abstract:

The eye contains closely related but widely different tissues, offering a unique opportunity to investigate the phenotype and function of monocyte-derived cell populations within functionally unique microenvironments in a single complex organ. The uveal tract and retina contain rich networks of immune cells that reside and traffic through the eye, these cells having been implicated in various ocular inflammatory processes and immune-mediated diseases. One such inflammatory condition is human posterior uveitis, an autoimmune disease mainly affecting the retina. As current treatments for posterior uveitis only serve to slow down disease progression, studies using animal models, namely, experimental autoimmune uveoretinitis (EAU), have focused on determining the key cellular and molecular mediators involved in disease initiation in order to expand the potential for novel therapeutic applications. The overall purpose of experiments in this thesis was to explore monocyte-derived cell populations of the uveal tract and retina, this being achieved by utilising a novel transgenic mouse model. Cx3cr1gfp/gfp transgenic mice on both BALB/c and C57Bl/6 backgrounds contain an enhanced green fluorescent protein (eGFP) encoding cassette knocked into the Cx3cr1 gene, disrupting its expression but facilitating GFP expression under the control of the Cx3cr1 promoter. Heterozygous (Cx3cr1+/gfp) mice were generated by crossing Cx3cr1gfp/gfp mice to wild-type (WT) mice. This transgenic model allowed for the exquisite visualisation of Cx3cr1-bearing monocyte-derived dendritic cells (DC) and macrophages in ocular tissues, whilst also enabling the investigation of a potential role for Cx3cr1 in recruiting monocyte-derived cells to the eye in steady-state and inflammatory conditions.

APA, Harvard, Vancouver, ISO, and other styles

24

Patel, Samikumar R. "Suprachoroidal drug delivery to the eye using hollow microneedles." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/47816.

Full text

Abstract:

Delivering drugs to effectively treat diseases of the back of the eye can be a challenging task. Although pharmacological therapies exist, drug delivery devices and techniques are not very effective at targeting delivery of drugs to the diseased tissues. This work introduces a novel approach to effectively deliver drugs to target tissues such as the choroid and retina. The approach involves a device, a hollow microneedle, to administer the drug formulation into a unique location in the eye, the suprachoroidal space. This new route of administration and a device to accomplish the delivery may provide an effective way to treat diseases of the choroid and retina. The first part of the work determines the ex-vivo feasibility of delivering materials within the suprachoroidal space. The results show that fluids and particles can be delivered into the suprachoroidal space of rabbit, pig and human eyes using a hollow microneedle. It further examines the important parameters for injection of the particles within the suprachoroidal space. The data shows that injection pressure and microneedle length are important parameters for effective delivery of particles. The results lead to a theory on the mechanism by which the particles are delivered into the suprachoroidal space. The second part of the research aims to develop a reliable in vivo delivery device and study the surface area coverage of materials injected into the suprachoroidal space. A hollow glass microneedle device is developed and for the first time shown to be effective in delivering a fluid into the suprachoroidal space in vivo. Up to 100 µL of India ink could be delivered into rabbit eyes in vivo and the spread within the suprachoroidal space is characterized. The results show that a single microneedle injection can cover a significant percentage of the available suprachoroidal space. This is the first study to examine the spread of a material injected into the suprachoroidal space of a live animal. A hollow metal microneedle device is also developed and shown to be effective. The device was able to inject up to 150 µL of latex into suprachoroidal space of fresh human cadaver eyes. The spread of latex is characterized and the results also show that a significant portion of the suprachoroidal space can be covered. The final part of the study examines the clearance of materials injected into the suprachoroidal space of rabbit eyes in vivo. First a comparison of a suprachoroidal injection to a conventional intravitreal injection shows that a suprachoroidal injection is more targeted to the chorioretinal tissues. In addition hollow microneedles are shown to effectively target macromolecules and a therapeutic antibody to the chorioretinal tissues. A study of the clearance kinetics show half lives within the suprachoroidal space on the order of several hours. Nano- and microparticles were also injected into the suprachoroidal space and showed very effective targeting. These non-degradable particles are shown to be present in the suprachoroidal space for months. Basic visual safety assessments identified no adverse effects from the injection of these materials. This represents the first study to compare intraocular clearance kinetics between a suprachoroidal injection and an intravitreal injection. It is also the first study to examine the clearance of a variety of materials from within the suprachoroidal space. Overall this work shows that microneedles have the capability to deliver a variety of materials into the suprachoroidal space of rabbit, pig, and human eyes. The injection can be done in a minimally invasive way with the proper design of an injection device and can target the chorioretinal tissues more effectively than the currently used method. In addition particles have long residence times in the suprachoroidal space, so a particle based drug formulation could provide sustained delivery to the eye. This work represents the first comprehensive study on using the suprachoroidal space as a drug delivery route and also the first study to use hollow microneedles to deliver formulations into the eye in vivo.

APA, Harvard, Vancouver, ISO, and other styles

25

Tong, Man-kit, and 湯文傑. "Sorbitol dehydrogenase does not contribute to the ischemia/reperfusion-induced oxidative stress and retinal injury." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50712822.

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

26

Coleman, Jason Edward. "Efficient transduction and targeted expression of lentiviral vector transgenes in the developing retina." [Gainesville, Fla.]: University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000665.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

DELL'AQUILA, FABIO. "GENE THERAPY FOR GYRATE ATROPHY OF CHOROID AND RETINA AND FOR USH1B RETINITIS PIGMENTOSA." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/884458.

Full text

Abstract:

Inherited Retinal Diseases (IRDs) represent a major cause of blindness worldwide. Adeno-associated viral (AAV) vector-based gene therapies represent the most promising treatments. We aimed to develop gene therapies for gyrate atrophy of the choroid and retina (GA) and Usher syndrome type 1B (USH1B) retinitis pigmentosa. GA is characterized by ornithine aminotransferase [OAT, coding sequence (CDS) ∽1.3 Kb] deficiency. We demonstrated in vitro expression and activity of 3XFlag-tagged human OAT (hOAT-3XFlag). AAV vector carrying the hOAT-3XFlag expression cassette improved the structural retinal defects in the Oat-/- mouse model of GA. Bi-allelic mutations in the Myosin7A gene (MYO7A) (CDS ∽6.7 Kb) cause USH1B, the most common combination of inherited congenital deafness and blindness. We demonstrated effective delivery and expression of MYO7A in mice and pigs using dual AAV vectors. During AAV manufacturing, we found a contaminant vector resulting from recombination between two homologous sequences in the AAV vector containing the 5’ half of hMYO7A. This was removed by changing one of the two sequences while maintaining the same MYO7A expression levels in vivo. We selected three therapeutic doses of dual AAV-hMYO7A that rescue retinal defects in shaker-1 mice, a mouse model of USH1B. These doses will be translated in patients with USH1B. In the same mouse model, we confirmed biological potency of dual AAV-hMYO7A that will be used in the clinical trial. Overall, these studies offer promising results, paving the way for a gene therapy of GA and for the clinical translation of dual AAV vectors in USH1B subjects.

APA, Harvard, Vancouver, ISO, and other styles

28

López, del Hoyo Natalia. "Role of Guanylate Cyclase Activating Proteins in photoreceptor cells of the retina in health and disease." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/283566.

Full text

Abstract:

In the last two decades, it has been done a thoroughly research about the role of Guanylate Cyclase Activating Proteins (GCAPs) in photoreceptor cells of the retina as activity regulators of Retinal Guanylate Cyclase (RetGC), which allow to restore cGMP levels to darkness ones when intracellular Ca2+ falls. However, little is known about: a) ¿What determines GCAPs distribution within the cell?, b) ¿Which other functions GCAP proteins, GCAP1 and GCAP2, carry out at other cellular compartments different from the sensory one? and c) ¿How they cause cell death when they are mutated? In this study we want address these questions. 1. First of all, we own a mouse model that expresses a GCAP2 mutated form unable to bind Ca2+ (bEF-GCAP2). Other mutations described for GCAP1 and present in some autosomic dominant Cone Rod Dystrophies (adCORD), prevent Ca2+ binding to some of its EF-hand domains which produces the constitutive activation of RetGC, and consequently, high cGMP levels that result in toxicity for the cell. However, we observe that our model causes the death by other mechanism, as RetGC is not activated by GCAP2, because GCAP2 is retained in the inner segment and does not translocate to the sensory compartment. We want to identify interactions that GCAP2 establish differentially in this compartment and could be retaining it. We find out 14-3-3 family of proteins by mass-spectrometry and liquid chromatography. Furthermore, bEF-GCAP2 is abnormally phosphorylated in vivo and GCAP2 phosphorylation promotes its binding to 14-3-3 binding. We demonstrate that GCAP2 phosphorylation in residue serine 201 is the cause of its retention in the inner segment, avoiding its translocation to the outer segment, and when we mutate serine 201 into a glycine, this retention is reverted in vivo. Finally, we propose that GCAP2 phosphorylation and its binding to 14-3-3 is what retains GCAP2 in the inner segment, and this happens in a balance way during dark/light day cycles. When this system overloads will cause retinal degeneration by the formation of aggregates. We believe that mutations in GCAP2 or light conditions promoting GCAP2 accumulation in its Ca2+-free form in the inner segment of the cell, bring to cell death by GCAP2 conformational instability. Most important, we propose that this will also apply for genetic scenarios mimicking the effects to constant light exposure, the so called “equivalent-light” scenarios. 2. Secondly, as a result of the identification of GCAP2 interaction to RIBEYE (Venkatesan et al. 2010) the major component of synaptic ribbons in the photoreceptor cell terminal, we developed an ultrastructural study of the role that GCAP2 may play in this compartment. Through confocal and electronic microscopy we have demonstrated the presence of GCAP1 and GCAP2 in rod synaptic ribbons. However, GCAP1 and GCAP2 are not necessary during synaptic ribbons assembling and basic maintenance. As GCAP2 overexpression in the wildtype background (which means a higher GCAP2:GCAP1 ratio) promotes ribbons disassembling, we propose that GCAP2 may play a role mediating the morphological changes that take place in the synaptic ribbons in response to variations in [Ca2+].
En las dos últimas décadas se ha investigado a fondo el papel que juegan las Proteínas Activadoras de Guanilato Ciclasa (GCAPs) en las células fotorreceptor de la retina como proteínas encargadas de regular la actividad de la Guanilato Ciclasa (GC). Sin embargo se sabe poco acerca de: a) ¿Qué determina la distribución de GCAPs en la célula?, b) ¿Qué otras funciones ejercen GCAP1 y GCAP2 en otros compartimentos celulares distintos al segmento sensorial? y c) ¿Cómo dan lugar a muerte celular cuando están mutadas? En este estudio hemos querido encarar estas preguntas. 1. En primer lugar, poseemos un modelo de ratón que expresa una forma mutante de GCAP2 que no une Ca2+ (bEF-GCAP2). A diferencia de otras mutaciones descritas para GCAP1, en que se ha observado que la muerte celular es producida por niveles tóxicos de cGMP, observamos que nuestro modelo produce la muerte celular por otro mecanismo en que GCAP2 se acumula en el segmento interno. Identificamos abundantemente las distintas isoformas de 14-3-3 como interactores diferenciales de bEF-GCAP2, que a su vez está anormalmente fosforilada in vivo. Tras una serie de experimentos para caracterizar esta interacción, proponemos que la fosforilación de GCAP2 y su unión a 14-3-3 retienen a GCAP2 en el segmento interno, y si este mecanismo se sobrecarga por a) mutaciones en GCAP2, b) condiciones de luz que promuevan la acumulación de GCAP2 en su forma libre de Ca2+ en el segmento interno o c) condiciones genéticas que mimeticen los efectos de exposición a luz prolongada, tendría lugar la degeneración de la retina por la formación de agregados debido a la inestabilidad conformacional de GCAP2. 2. En segundo lugar, tras la identificación de la interacción de GCAP2 con RIBEYE (Venkatesan et al. 2010), el componente mayoritario de las cintillas sinápticas de fotorreceptores, realizamos un estudio ultrastructural del papel que puede estar jugando GCAP2 en este compartimento mediante microscopia electrónica y confocal, demostrando la presencia de GCAP1 y GCAP2 en las cintillas sinápticas de bastones. GCAP1 y GCAP2 son prescindibles en el ensamblaje y mantenimiento básico de las cintillas sinápticas, pero la sobreexpresión de GCAP2 en el fenotipo salvaje, que incrementa el ratio GCAP2:GCAP1, promueve el desensamblaje de las cintillas. Proponemos que GCAP2 podría jugar un papel mediando cambios morfológicos en las cintillas sinápticas promovidas por cambios en [Ca2+].

APA, Harvard, Vancouver, ISO, and other styles

29

Castro, Miró Marta de. "Metodologies d'alt rendiment per a la identificació de noves mutacions i gens causants de distròfies de retina: estudi funcional de nous candidats." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/456372.

Full text

Abstract:

Les distròfies de retina (DR) formen un ampli grup dins les patologies hereditàries de la visió que es caracteritza perquè cursen amb afectació retinal i per la seva elevada heterogeneïtat clínica i genètica. A nivell clínic les DR es classifiquen entre formes estacionàries o progressives i formes maculars o generalitzades i, en general, són difícils de diagnosticar. A nivell genètic s’han identificat més de 260 gens causals, associats a formes sindròmiques i no sindròmiques, que s’hereten seguint els patrons coneguts d’herència mendeliana. A més, algunes DR, particularment les que afecten el nervi òptic, són causades per gens mitocondrials. Els avenços realitzats aquests darrers anys en les metodologies de seqüenciació massiva han contribuït molt positivament a la identificació de nous gens i noves mutacions, millorant molt el rendiment del diagnòstic genètic de les DR i obrint noves vies per assegurar el diagnòstic clínic, predir l’evolució de la patologia i identificar noves dianes terapèutiques. El treball que es presenta en aquesta tesi s’emmarca en una línia d’investigació del grup que té com a objectius: 1) Millorar l’eficàcia i facilitar el rendiment del diagnòstic genètic de les DR i, 2) contribuir a la identificació de nous gens causals. En relació al primer punt, en el primer capítol de la tesi es descriu la versió optimitzada i ampliada (100 gens) d’un xip que havia dissenyat prèviament el grup per al diagnòstic genètic de les DR, basat en l’anàlisi cosegregació amb marcadors de tipus SNP. Emprant aquest xip s’analitza una cohort de 36 famílies espanyoles afectades de DR. En els darrers anys, les metodologies de seqüenciació massiva, especialment l’estudi de l’exoma o WES, han revolucionat el diagnòstic genètic i han esdevingut especialment rellevants per a l’estudi de malalties com les DR, genèticament molt heterogènies, i per tant inabordables amb la seqüenciació capil·lar convencional (Sanger), pels costos i temps que implicaria aquest tipus d’estudi. El segon capítol de la tesi descriu el diagnòstic genètic per WES de 33 famílies afectades de DR. Aquest treball ha conduït a la identificació de nous gens i noves mutacions causals, i no només demostra que la seqüenciació massiva és l’eina adient per aquest tipus de diagnòstic genètic, molt més eficaç, ràpida i fiable que els xips emprats anteriorment, sinó que obre noves perspectives d’estudi de les bases genètiques d’aquestes patologies. Finalment, es recull l’estudi de dues famílies, inicialment diagnosticades a nivell clínic com a retinosi pigmentària, la DR més freqüent, i on l’anàlisi amb el xip DR va donar resultats negatius. El diagnòstic genètic mitjançant WES ha revelat la presència de noves mutacions en el gen que causa la coroiderèmia, CHM, i la necessitat d’una reavaluació diagnòstica confirmatòria. Aquest estudi aporta dades rellevants per establir relacions genotip-fenotip en relació a la contribució d’altres variants patogèniques en gens DR que actuen de modificadors i de la inactivació del cromosoma X en el cas de femelles portadores.
Retinal dystrophies (RD) are a group of inherited visual disorders characterized by extensive clinical and genetic heterogeneity, with more than 260 genes associated with non-syndromic and syndromic forms of the disorder. They can be inherited under all possible mendelian patterns, and also through the mitochondria. This extreme heterogeneity challenges the genetic diagnosis. However, gene identification is crucial to secure clinical diagnosis, instrumental for genetic counselling and now becomes a key step for patient prioritization for the current and upcoming gene therapy treatments. In this Thesis, we have studied in depth the molecular diagnosis of several RD with the aim to increase its efficiency and contribute to the identification of novel causative genes. As a first approach, we used an extended chip, developed from a previous version designed by the group, that allows cosegregation analysis of 100 RD genes in affected families using single-nucleotide polymorphisms (SNPs). This led to the genetic resolution of 17 out of 36 families and allowed us to nominate candidate pedigrees for the search of novel disease-causing genes. Recently, high-throughput methodologies have revolutionized the genetic diagnosis of mendelian heterogeneous disorders, as the RD. In particular, whole-exome sequencing (WES) makes it possible to analyse all known RD genes and also to explore the presence of mutations in novel genes, making the genetic diagnosis time- and cost-effective. The second part of the Thesis reports the genetic diagnosis of 33 RD families using WES. A total of 28 families were diagnosed with a clear or a plausible candidate. Besides, the genetic diagnosis has prompted the clinical re-evaluation of some patients and highlighted undiagnosed clinical syndromic disorders. In addition, four new RD genes have been identified and functional studies have been performed to provide the pathogenic bases of CEP250. Choroideremia (CHM) is an X-linked retinal dystrophy also belonging to the family of RD disorders. The third chapter of the thesis deals with WES analysis of selected patients of two RD families. Bioinformatics analysis of WES data has highlighted two novel causative mutations in CHM and supported the choroideremia diagnosis attained after accurate clinical reevaluation. Moreover, this study illustrates a severe multi-mendelian phenotype in one family caused by dominant pathogenic mutations in PAX6 and PDE6B besides CHM.

APA, Harvard, Vancouver, ISO, and other styles

30

Yang, Di, and 楊荻. "Neuroprotective effects of lycium barbarum extracts in cerebral and retinal ischemia/reperfusion injury." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206738.

Full text

Abstract:

Ischemic stroke is a devastating cerebrovascular disease resulting in high mortality rate and distressing sequelae such as hemiplegia, ataxia and even visual impairment. Retinal ischemia refers to a common pathological feature shared by many blinding diseases including retinal vascular occlusions, diabetic retinopathy, glaucoma, and retinopathy of prematurity. Ischemia/reperfusion injury is implicated in both of these pathological conditions, which greatly impact on one’s daily life. The eventual consequence of the insult is irreversible neuronal cell death and functional deterioration. Apart from current symptomatic treatment for these diseases, researchers and clinicians are dedicated to look for ideal neuroprotectant to meet the clinical needs. Traditional Chinese medicine has been received accumulating attention in recent years, and Lycium barbarum is one of them. The polysaccharides (LBP) utilized in the present study are the rich extracts of the fruit of Lycium barbarum that has been shown to exert many biological effects. This study aims to evaluate its protective effects in cerebral and retinal ischemia, which has not yet been fully investigated. A well-established rodent model, middle cerebral artery occlusion, was utilized in the present study to mimic cerebral and retinal ischemia/reperfusion injury. In the study of cerebral ischemia, both pre-treatment and post-treatment of LBP were explored. Seven-day LBP pre-treatment revealed significant protection against neurological deficits and cerebral infarction. Besides, it attenuated cerebral edema and glial activation, as well as preserved blood-brain barrier integrity. Further study showed that these beneficial effects of LBP pre-treatment might act via anti-apoptosis, antioxidation and anti-inflammation. However, similar findings were not noted in LBP post-treatment experiments, possibly due to the timing of intervention. In the investigation of retinal ischemia, the observation time was prolonged to 7 days after the insult. Electroretinogram was used to evaluate the functional alternation of retinal neurons. Sustained retinal dysfunction was induced by two-hour ischemia. LBP pre-treatment with continuous daily supplementation effectively alleviated visual dysfunction and protected the retina from morphological impairment including neuronal death, glial activation and blood-retinal barrier disruption. Similarly, these protective effects might be associated with the involvement of attenuation of apoptosis and oxidative stress. In conclusion, LBP pre-treatment with continuous daily supplementation protected the brain and retina, both functionally and morphologically, from ischemia/reperfusion injury. This dosing regimen hold great promise in serving as a prophylactic neuroprotectant in patients at high risk for ischemic stroke, as well as preserving normal visual function and reducing irreversible neuronal death in ischemic retinopathies. Further studies on the active ingredients and underlying mechanisms would be informative for better application of LBP in clinical situation.
published_or_final_version
Ophthalmology
Doctoral
Doctor of Philosophy

APA, Harvard, Vancouver, ISO, and other styles

31

Silva, Germana Alegro da [UNESP]. "Efeitos do citrato de sildenafila sobre a neuroproteção na neuropatia óptica, em ratos (Lewis/SsNHsd) com glaucoma agudo." Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/121866.

Full text

Abstract:

Made available in DSpace on 2015-04-09T12:28:07Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-30Bitstream added on 2015-04-09T12:48:22Z : No. of bitstreams: 1 000814908.pdf: 2391041 bytes, checksum: 13d22f38c1b9f1872035e29fa1940b72 (MD5)
Projetam-se que mais de 80 milhões de pessoas no mundo e um número significativo de animais serão atingidos pelo glaucoma até o final desta década. A doença perpetra-se como sem solução, obrigando a que se desenvolvam alternativas terapêuticas mais eficazes. A perda de visão decorre da morte de células ganglionares da retina (CGR) e de seus axônios, que compõem as fibras do nervo óptico. Avanços na compreensão da fisiopatologia evidenciam que isquemia local e que anormalidades de perfusão são condições decisivas na patogênese da neuropatia. Mostrou-se que o Sildenafila, fármaco vasodilatador, inibe a fosfodiesterase do tipo 5 (PDE-5), aumenta os níveis de guanosina monofosfato cíclica, prolonga efeitos do óxido nítrico (ON) e aumenta a sobrevida celular em modelos de lesão isquêmica. Objetivou-se avaliar o efeito neuroprotetor do tratamento citrato de sildenafila em ratos com hipertensão ocular aguda induzida, à histopatologia e à morfometria da retina e quanto à avaliação da expressão de marcadores relacionados à sobrevivência das CGR, empregando-se a imunohistoquímica (IHC) e a marcação TUNEL. Os Parâmetros histológicos observados foram: alterações celulares, vasculares e teciduais e os morfométricos foram: espessura das camadas da retina e contagem de células ganglionares. À IHC, observou-se a marcação da caspase-9, da caspase-3, do Bcl-2, da NOS-2, da PDE- 5, e da PDE-6. Foram avaliados olhos de 27 ratos, machos, adultos (Lewis/SsNHsd). Compuseram-se cinco grupos, um grupo controle composto por 3 animais, sem glaucoma e sem tratamento, e quatro grupos tratados compostos, cada um, por 6 animais com glaucoma agudo unilateral induzido, dos quais 3 foram tratados com Sildenafila e 3 tratados com placebo. Esses grupos foram separados conforme dia de indução do glaucoma até a eutanásia, em 1, 13, 14 e 20 dias, e receberam diferentes doses e períodos de tratamento. A indução do glaucoma ...
Protrude more than 80 million people worldwide and a significant number of animals are affected by glaucoma by the end of this decade. The disease perpetrates as unresolved, forcing them to develop more effective therapeutic alternatives. Vision loss results from the death of retinal ganglion cells (RGCs) and their axons, the fibers that make up the optic nerve. Advances in understanding the pathophysiology show that local ischemia and perfusion abnormalities are critical in the pathogenesis of neuropathy conditions. It has been shown that sildenafil drug vasodilator, inhibits phosphodiesterase type 5 (PDE -5) increases the levels of cyclic guanosine monophosphate extends effects of nitric oxide (NO) and increases cell survival in models of ischemic injury. Aimed to evaluate the neuroprotective effect of sildenafil citrate treatment in rats with induced acute ocular hypertension, by histopathological and morphometric examination of the retina and the evaluation of the expression of markers related to RGC survival , using immunohistochemistry (IHC) and TUNEL labeling. The observed histological parameters: cellular , tissue and vascular and morphometric changes were: thickness of the layers of the retina and ganglion cell count , IHC, there was labeling of caspase-9, caspase-3, Bcl-2, NOS-2, PDE-5, and PDE-6. Eyes of 27 rats, adult (Lewis/ SsNHsd) were evaluated after acute unilateral elevation of intraocular pressure (IOP). Composed by five groups , a control group of 3 animals without glaucoma and untreated and four treated groups consisting of 6 animals with induced unilateral acute glaucoma, of which 3 were treated with Sildenafil and 3 with placebo, these groups were separated by days of glaucoma´s induction to euthanasia, and they received districts dose and period of treatment. The induction of glaucoma was made by anterior chamber paracentesis needle attached to a bottle of saline solution 0.9 %, provided the height of 150 cm ...

APA, Harvard, Vancouver, ISO, and other styles

32

Silva, Germana Alegro da. "Efeitos do citrato de sildenafila sobre a neuroproteção na neuropatia óptica, em ratos (Lewis/SsNHsd) com glaucoma agudo /." Jaboticabal, 2014. http://hdl.handle.net/11449/121866.

Full text

Abstract:

Orientador: José Luiz Laus
Banca: Renée Laufer Amorim
Banca: Andréia Vitor Couto do Amaral
Resumo: Projetam-se que mais de 80 milhões de pessoas no mundo e um número significativo de animais serão atingidos pelo glaucoma até o final desta década. A doença perpetra-se como sem solução, obrigando a que se desenvolvam alternativas terapêuticas mais eficazes. A perda de visão decorre da morte de células ganglionares da retina (CGR) e de seus axônios, que compõem as fibras do nervo óptico. Avanços na compreensão da fisiopatologia evidenciam que isquemia local e que anormalidades de perfusão são condições decisivas na patogênese da neuropatia. Mostrou-se que o Sildenafila, fármaco vasodilatador, inibe a fosfodiesterase do tipo 5 (PDE-5), aumenta os níveis de guanosina monofosfato cíclica, prolonga efeitos do óxido nítrico (ON) e aumenta a sobrevida celular em modelos de lesão isquêmica. Objetivou-se avaliar o efeito neuroprotetor do tratamento citrato de sildenafila em ratos com hipertensão ocular aguda induzida, à histopatologia e à morfometria da retina e quanto à avaliação da expressão de marcadores relacionados à sobrevivência das CGR, empregando-se a imunohistoquímica (IHC) e a marcação TUNEL. Os Parâmetros histológicos observados foram: alterações celulares, vasculares e teciduais e os morfométricos foram: espessura das camadas da retina e contagem de células ganglionares. À IHC, observou-se a marcação da caspase-9, da caspase-3, do Bcl-2, da NOS-2, da PDE- 5, e da PDE-6. Foram avaliados olhos de 27 ratos, machos, adultos (Lewis/SsNHsd). Compuseram-se cinco grupos, um grupo controle composto por 3 animais, sem glaucoma e sem tratamento, e quatro grupos tratados compostos, cada um, por 6 animais com glaucoma agudo unilateral induzido, dos quais 3 foram tratados com Sildenafila e 3 tratados com placebo. Esses grupos foram separados conforme dia de indução do glaucoma até a eutanásia, em 1, 13, 14 e 20 dias, e receberam diferentes doses e períodos de tratamento. A indução do glaucoma ...
Abstract: Protrude more than 80 million people worldwide and a significant number of animals are affected by glaucoma by the end of this decade. The disease perpetrates as unresolved, forcing them to develop more effective therapeutic alternatives. Vision loss results from the death of retinal ganglion cells (RGCs) and their axons, the fibers that make up the optic nerve. Advances in understanding the pathophysiology show that local ischemia and perfusion abnormalities are critical in the pathogenesis of neuropathy conditions. It has been shown that sildenafil drug vasodilator, inhibits phosphodiesterase type 5 (PDE -5) increases the levels of cyclic guanosine monophosphate extends effects of nitric oxide (NO) and increases cell survival in models of ischemic injury. Aimed to evaluate the neuroprotective effect of sildenafil citrate treatment in rats with induced acute ocular hypertension, by histopathological and morphometric examination of the retina and the evaluation of the expression of markers related to RGC survival , using immunohistochemistry (IHC) and TUNEL labeling. The observed histological parameters: cellular , tissue and vascular and morphometric changes were: thickness of the layers of the retina and ganglion cell count , IHC, there was labeling of caspase-9, caspase-3, Bcl-2, NOS-2, PDE-5, and PDE-6. Eyes of 27 rats, adult (Lewis/ SsNHsd) were evaluated after acute unilateral elevation of intraocular pressure (IOP). Composed by five groups , a control group of 3 animals without glaucoma and untreated and four treated groups consisting of 6 animals with induced unilateral acute glaucoma, of which 3 were treated with Sildenafil and 3 with placebo, these groups were separated by days of glaucoma's induction to euthanasia, and they received districts dose and period of treatment. The induction of glaucoma was made by anterior chamber paracentesis needle attached to a bottle of saline solution 0.9 %, provided the height of 150 cm ...
Mestre

APA, Harvard, Vancouver, ISO, and other styles

33

Hájek, Josef. "Biometrický systém pro rozpoznávání podle sítnice a duhovky oka." Doctoral thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2017. http://www.nusl.cz/ntk/nusl-412584.

Full text

Abstract:

Tato disertační práce se zabývá biometrickým a medicínským zařízením pro simultánní snímání duhovky a sítnice oka v jednom kroku. V případě biometrického zaměření je práce rozšířena o vzájemnou fúzi těchto dvou biometrik do jedné šablony, kdy multimodální systém vykazuje mnohem lepší parametry než systém unimodální, a to především ve větší unikátnosti, univerzálnosti a velmi obtížně proveditelnému útoku (až téměř nemožnému) na senzor. V případě medicínského využití práce dále rozvíjí detekci a klasifikaci nemocí pro základ expertního systému pro oftalmologické účely, který bude umožňovat pomoc lékaři při stanovení diagnózy nálezu v obrazu sítnice (či duhovky) oka.

APA, Harvard, Vancouver, ISO, and other styles

34

Mitzel, Gina Marie. "The Impact of Genetics, Socioeconomic Status, and Lifestyle Factors on Visual Health in an Adult Population." Thesis, University of North Texas, 2010. https://digital.library.unt.edu/ark:/67531/metadc33187/.

Full text

Abstract:

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

APA, Harvard, Vancouver, ISO, and other styles

35

Latasiewicz, Marta Joanna. "Familial amyloid polyneuropathy: ocular complications and the use of novel non-invasive imaging techniques to assess retinal involvement." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/670403.

Full text

Abstract:

Familial amyloid polyneuropathy (FAP) is a hereditary condition characterized by systemic deposition of transthyretin (TTR), which causes debilitating peripheral polyneuropathy, cardiopathy, nephropathy and usually after a few years, ophtalmopathy. Occasionally the onset can be atypical and the diagnosis of FAP is reliant on identifying ocular amyloid deposition clinically and histopathologically. However, images of TTR derived from the eye, identified using immunolabeling techniques, have so far not been published. In ocular tissues FAP can cause sight-threatening complications such as glaucoma and retinal amyloid angiopathy. Glaucoma in FAP often requires surgical treatment. Nonpenetrating deep sclerectomy (NPDS) is a surgical technique with several advantages over the traditional trabeculectomy. It is successfully performed in primary and many types of secondary open-angle glaucoma, but so far with limited reports in FAP. Retina imaging modalities, such as optic coherence tomography (OCT) and autofluorescence (AF), have significant value in the assessment of retinal pathologies. Fluorescein angiography is the conventional method of evaluating retinal vasculature, but requires injection of fluorescein, which has several side effects and contraindications. Recently a new non-invasive modality, the OCT angiography (OCT-A) has become a useful tool for visualizing posterior pole blood circulation. In patients with FAP the use of OCT-A has so far not been reported and only few cases of AF findings were published. This doctoral thesis, presented as a compendium of publications, is divided into three parts. The first part (Paper 1) aims to present the immunostaining images of TTR amyloid derived from the vitreous of a series of patients with FAP, which demonstrates vitreous biopsy as a valid diagnostic tool, especially in clinically challenging cases. The second part (Paper 2) is a retrospective review of clinical charts of patients with FAP to determine the prevalence and characteristics of open-angle glaucoma secondary to FAP. It reveals the particularly quick progression of glaucoma in FAP and its increased risk in patients with a previous vitrectomy. Surgical management and outcomes of the affected patients are presented, indicating that NPDS is a safe and effective treatment of glaucoma secondary to FAP. The third part (Paper 3) is an observational cross-sectional study of retinal findings in patients with FAP. It gives a descriptive analysis of retinal images in FAP using novel non-invasive techniques: AF, OCT, OCT-A, and ultra-wide-field (UWF) retinography. These modalities can be used to detect perivascular retinal amyloid deposits, as well as microvascular changes including areas of non-perfusion, allowing better understanding of the pathology, complications and prognosis of patients with FAP. It also shows that amyloid retinopathy is more frequent than previously reported. The thesis outcomes emphasize glaucoma and retinopathy as the severe irreversible complications of FAP and need for addressing them promptly. This is especially important in establishing adequate regular eye reviews in patients with FAP and identifying those individuals requiring stricter ophthalmological care to prevent vision loss.
La polineuropatía amiloidótica familiar (PAF) es una enfermedad hereditaria caracterizada por el depósito sistémico de transtiretina (TTR), que resulta en polineuropatía periférica debilitante, cardiopatía, nefropatía y, habitualmente, después de unos años, oftalmopatía. Ocasionalmente, el inicio puede ser atípico y el diagnóstico de PAF depende de la identificación de depósitos de amiloide en tejidos oculares clínicamente e histopatológicamente. Sin embargo, hasta ahora no se han publicado imágenes de TTR derivadas del ojo, identificadas utilizando técnicas de inmunotinción. En los tejidos oculares, la PAF puede causar complicaciones amenazantes para la vista, como el glaucoma y la angiopatía amiloide de la retina. El glaucoma en la PAF frecuentemente requiere tratamiento quirúrgico. La esclerectomía profunda no penetrante (EPNP) es una técnica quirúrgica con varias ventajas sobre la trabeculectomía tradicional. Se realiza con éxito en glaucoma de ángulo abierto primario y muchos tipos de glaucoma secundario, pero hasta ahora con pocos casos descritos en PAF. Las modalidades de imágen de retina, como la tomografía de coherencia óptica (OCT) y la autofluorescencia (AF), tienen un valor importante en la evaluación de las patologías retinianas. La angiografía con fluoresceína es el método convencional para evaluar la vasculatura retiniana, pero requiere la inyección de fluoresceína, que tiene varios efectos secundarios y contraindicaciones. Recientemente, una nueva modalidad no invasiva, la angiografía OCT (OCT-A) se ha convertido en una herramienta útil para visualizar la circulación sanguínea del polo posterior. En pacientes con PAF, el uso de OCT-A no ha sido publicado hasta ahora, y solo se han descrito dos casos de hallazgos de AF. Esta tesis doctoral, presentada como un compendio de publicaciones, se divide en tres partes. La primera parte (Artículo 1) tiene como objetivo presentar las imágenes de inmunotinción de TTR amiloide derivado del vítreo en una serie de pacientes con PAF, lo que demuestra que la biopsia vítrea es una herramienta de diagnóstico válida, especialmente en casos clínicamente atípicos. La segunda parte (Artículo 2) es una revisión retrospectiva de las historias clínicas de pacientes con PAF para determinar la prevalencia y las características del glaucoma de ángulo abierto secundario a la PAF. Revela la progresión particularmente rápida del glaucoma en la PAF y su mayor riesgo en pacientes con vitrectomía previa. Se ha presentado el tratamiento quirúrgico y los resultados de los pacientes afectados, lo que indica que EPNP es un tratamiento seguro y efectivo para el glaucoma secundario a PAF. La tercera parte (Artículo 3) es un estudio transversal observacional de hallazgos retinianos en pacientes con PAF. Se expone un análisis descriptivo de las imágenes de la retina en PAF utilizando nuevas técnicas no invasivas: AF, OCT, OCT-A y retinografía de campo amplio (UWF). Estas modalidades se pueden utilizar para detectar depósitos amiloides perivasculares de la retina, así como cambios microvasculares que incluyen áreas de no perfusión, lo que permite una mejor comprensión de la patología, las complicaciones y el pronóstico de los pacientes con PAF. También se muestra que la retinopatía amiloidea es más frecuente de lo que se publicó anteriormente. Los resultados de la tesis enfatizan el glaucoma y la retinopatía como las complicaciones irreversibles graves de la PAF y la necesidad de abordarlos precozmente. Esto es especialmente importante para establecer revisiones oculares regulares adecuadas en pacientes con PAF e identificar a aquellas personas que requieren atención oftalmológica más estricta para prevenir la pérdida de visión.

APA, Harvard, Vancouver, ISO, and other styles

36

Riera, Gibernau Marina. "Models in vivo i in vitro per a l'estudi de gens causants de distròfies de retina: CERKL i RP2." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/120425.

Full text

Abstract:

Les distròfies de retina (DR) engloben un conjunt de patologies caracteritzades per la degeneració dels fotoreceptors i les cèl•lules de l’epiteli pigmentari de la retina, i representen la major causa de ceguesa hereditària. Són malalties altament heterogènies clínica i genèticament. La retinosi pigmentària (RP) és la DR més freqüent, amb una prevalença d'1:4000 i més d'un milió d'afectats arreu del món. Fins l'actualitat, s'han descrit gairebé 200 gens i loci responsables de DR, però s'estima que aquests expliquen poc més de la meitat dels casos. En els últims anys, s'han centrat molts esforços en la cerca de nous gens i mutacions, fonamental per tal d’oferir als pacients i als seus familiars un diagnòstic genètic acurat i, en alguns casos, una bona prognosi de la malaltia. No obstant, una vegada identificada la causa molecular, l'estudi funcional no es presenta com una tasca trivial. Si bé l'estadi final de les DR és comú en la majoria dels casos, -la mort per apoptosi dels fotoreceptors-, els diferents gens DR participen en una gran diversitat de vies i aspectes cel•lulars dels fotoreceptors. En aquest context, és molt important combinar estratègies in silico, in vitro i in vivo per abordar-ne l'estudi acurat. El treball d'aquesta tesi doctoral s'ha basat en l'obtenció de models in vivo i in vitro per a l'estudi de dos gens causants de distròfies de retina, CERKL i RP2. El primer, va ser descrit pel nostre grup l'any 2004 com a causant de RP d’herència autosòmica recessiva. Malgrat les primers anàlisis de predicció varen revelar una elevada homologia amb la quinasa de ceramides (CERK), diversos estudis han fracassat a l'hora de validar l'activitat fosforilativa de CERKL. A l'inici d'aquesta tesi, CERKL es presentava com una proteïna òrfena de funció. Per aquesta raó, varem iniciar-ne l'aproximació funcional, basada primerament en l'estudi transcripcional en detall del gen a la retina. Els resultats varen mostrar una gran complexitat transcripcional, deguda principalment a l'splicing alternatiu i a l'ús de promotors alternatius. A més, es varen identificar promotors específics de teixit, fet que posava de manifest l’elevada regulació en l’expressió d’aquest gen. Pel que fa a la localització cel•lular de la proteïna, CERKL presenta un clar dinamisme cel•lular entre els compartiments citoplasmàtic i nuclear, amb una localització depenent de tipus cel•lular a la retina murina. Tot plegat, suggeria un paper multifuncional de CERKL. Per abordar la seva contribució a la degeneració retinal, es varen generar dos models animals. D’una banda, un ratolí knockout Cerkl-/- i, de l’altra, un model knockdown en peix zebra. L’estudi acurat del fenotip ens va revelar una disfunció a nivell ganglionar i/o amacrí en el cas del model murí, acompanyada d’un augment de l’estrès i mort cel•lular en la retina. D’altra banda, en el cas del model en peix zebra, els animals presentaven ulls de mida reduïda, juntament amb defectes en la laminació de la retina i en la formació dels segments externs dels fotoreceptors. Segons els nostres resultats, Cerkl no sembla contribuir en el desenvolupament primerenc de la retina d’aquest teleosti, si bé podria participar en processos de degeneració secundaris. En ambdós models es va posar de manifest la contribució de CERKL en les vies d’estrès i apoptosi cel•lular. En el futur, quan les teràpies gèniques estiguin ben establertes i els pacients puguin accedir a elles, serà fonamental el coneixement de les bases genètiques de la malaltia i l’impacte molecular de les mutacions descrites en cada cas. En aquest context, s’han realitzat estudis tant in vitro com in vivo de dues mutacions identificades als gens CERKL i RP2 en famílies espanyoles. Les diferents anàlisis ens han permès comprovar l’impacte patogènic d’aquestes mutacions sobre els productes gènics, basat en la degradació o formació aberrant de les isoformes del mRNA. A més, en el cas de RP2, responsable de RP lligada al cromosoma X, hem reportat per primera vegada un cas de semi-dominància degut a mutacions en aquest gen. L’estudi de les mostres de les dones portadores de la família ens han permès demostrar un biaix en l’expressió dels al•lels de RP2, segurament donada per la inactivació no atzarosa del cromosoma X, com a causa directa del fenotip.
Retinal dystrophies (RD), the major cause of incurable familial blindness in the Western world, are monogenic disorders characterized by progressive dysfunction of photoreceptor and retinal pigment epithelium cells. RD is a group of extremely heterogeneous diseases that show substantial clinical and genetic overlap. Highthroughput technologies have greatly improved our knowledge of the genetic basis of RD. Indeed, more than 180 RD genes have already been reported and this number is constantly increasing. However, although RD genes are known to be involved in a variety of celular and molecular processes in the retina, we are still far from understanding the contribution of most of them to the disease. In this context, we have aimed to study the contribution to the pathogenesis of two RD genes: CERKL and RP2. The first was identified by our group in 2004, as a responsible for autosomic recessive retintitis pigmentosa (RP). To shed light on the pathogenicity of the mutations in this gene, we aimed to characterize its transcriptional repertoire. Our results showed an unexpected multiplicity of CERKL transcriptional start sites plus a high variety of alternative splicing. In order to approach the function of the retinal dystrophy CERKL gene we generated a knockout mouse model. KO animals showed clear and consistent signals of gliosis and retinal stress, togheter with a non-progressive perturbation of ganglion cells. The failure to reproduce the human phenotype in the mouse, not unusual in other hereditary retinal disorders, prompted us to explore zebrafish as an alternative model. The phenotype resulted in abnormal eye development with lamination defects, failure to develop photoreceptor outer segments, increased apoptosis of retinal cells and small eyes. Our data supported that zebrafish Cerkl does not interfere with proliferation and neural differentiation during early developmental stages but is relevant for survival and protection of the retinal tissue. Finally, we have analized the pathogenicity of a new variant in RP2, a X-linked RP gene. The study of the RP2 splicing pattern in blood samples of patients and carrier females showed a aberrant mRNA transcript. High levels of variation observed for RP2-spliced products in female carriers supports X chromosome–skewed inactivation as the cause of the disease in the affected females.

APA, Harvard, Vancouver, ISO, and other styles

37

Wolk, Alyson M. "The Role of the Retinal Pigment Epithelium in Sorsby Fundus Dystrophy." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1606842751125309.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Borrego, Domènech Elena. "La funció de CERKL a la retina: generació d’un model de ratolí i anàlisi de la seva implicació en la resposta a estrès oxidatiu." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673997.

Full text

Abstract:

CERKL és un gen causant de Retinosi Pigmentària, una malaltia genètica de caràcter mendelià, malaltia caracteritzada per la mort dels fotoreceptors i que, amb el pas del temps, desemboca en ceguera. Malgrat els esforços de diferents grups d’investigació, incloent-hi el nostre grup (que va ser el descobridor del gen), la funció de CERKL encara roman desconeguda. Els intents a l’hora de generar un model animal que mimetitzi el fenotip humà han dificultat l’estudi funcional d’aquest gen i, conseqüentment, s’ha alentit poder trobar una teràpia efectiva que pugui aturar la progressió de la malaltia o curar als pacients amb mutacions a CERKL. Per aquest motiu, en aquesta Tesi ens plantejarem estudiar el paper de CERKL a la retina i així, apropar-nos al disseny efectiu d’una teràpia o tractament que millori el pronòstic de la malaltia. Els objectius concrets plantejats en aquesta Tesi són: 1. Generació i caracterització d’un nou model murí de Cerkl 1.1. Generació de ratolins Cerkl knockout mitjançant la tècnica d’edició gènica CRISPR/Cas9 1.2. Caracterització fenotípica de la retina dels ratolins Cerkl knockout en comparació amb ratolins control (wild-type) 2. Determinació del paper de CERKL davant un estímul d’estrès oxidatiu tan in vitro com in vivo 2.1. Estudi de la dinàmica cel·lular de CERKL in vitro 2.2. Identificar el rol de CERKL en resposta a un estímul d’estrès oxidatiu o lumínic in vivo i ex vivo 2.3. Generar i caracteritzar l’expressió de CERKL en organoides tridimensionals de retina a partir de fibroblasts d’un pacient i un control 2.4. Determinar la resposta front a l’estrès oxidatiu en els organoides 2.5. Comparar l’efecte de l’estrès oxidatiu en el model humà d’organoides i les retines del model murí 3. Comprovar l’efectivitat de l'alliberament d'àcids nucleics mitjançant nanopartícules d’or com a prova de principi de teràpia gènica 3.1. Determinar el sistema d’entrada de les nanopartícules en cèl·lules en cultiu 3.2. Comprovar l’eficiència d’entrada de les nanopartícules en cèl·lules en cultiu en comparació amb els lipoplexes convencionals 3.3. Explorar la possibilitat d’alliberar àcids nucleics terapèutics mitjançant nanopartícules en retines ex vivo.

APA, Harvard, Vancouver, ISO, and other styles

39

Makhoul, Maya. "Activation des cellules rétiniennes lors d'uvéites autoimmunes expérimentales: rôle des cytokines pro-inflammatoires et effet du transfert du gène SOCS1." Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209688.

Full text

Abstract:

Les uvéites non infectieuses sont considérées actuellement comme une des plus importantes cause de déficience visuelle dans la population des jeunes adultes. Les uvéites non infectieuses sont des atteintes inflammatoires de la rétine et de l’uvée et sont généralement considérées comme autoimmunes et initiées par la perte de la tolérance immune aux protéines rétiniennes. Elles sont orchestrées d’une part, systémiquement par deux sous populations lymphocytaires dont la signature cytokinique est l’IFNγ (Th1) et l’IL-17 (Th17) et d’autre part, localement, par l’activation du tissu rétinien. Néanmoins, la vision systémique actuelle est plus complexe et fait intervenir une activation pathologique de l’immunité innée, donnant une composante d’autoinflammation aux uvéites non infectieuses. En plus de ce volet systémique, de nombreux travaux attestent de l’importance de l’activation des cellules rétiniennes dans le développement d’uvéites non infectieuses. Loin de jouer un rôle passif durant la maladie, elles vont être stimulées par une série de molécules pro-inflammatoires et ainsi permettre le recrutement et l’activation de cellules immunocompétentes.

Notre travail de thèse s’inscrit précisément dans ce contexte du rôle de l’activation des cellules rétiniennes et plus spécifiquement de celles de la barrière hémato rétinienne (BHR) dans le développement d’uvéite non infectieuses.

Lors de ce travail, nous avons tout d’abord caractérisé in vivo, dans deux modèles expérimentaux, l’expression de la molécule d’adhésion VCAM-1 (Vascular Adhesion Molecule) sur les cellules de la BHR. VCAM-1 est une molécule d’adhésion qui facilite l’extravasation des leucocytes du sang vers les tissus. Nous avons montré que VCAM-1 n’est pas exprimé dans l’œil sain mais est induit progressivement lors de la maladie et que l’intensité et l’extension de son expression étaient dépendantes de la sévérité de la maladie. Par ailleurs, nous avons montré que VCAM-1 pouvait être induit sur l’ensemble des cellules de la BHR.

Nous avons ensuite analysé in vitro, sur les cellules de l’EPR (Epithélium Pigmentaire Rétinien) qui forment la partie externe de la BHR, les effets antagonistes du TNFα sur l’induction des molécules de CMH de classe II par l’IFNγ. Durant le processus inflammatoire, l’EPR est la cible d’un ensemble de cytokines secrétées par les cellules inflammatoires. Il a été donc intéressant d’étudier les effets d’autres cytokines présentes lors de l’inflammation sur l’induction du CMHII par l’IFNγ au niveau de l’EPR. Nous avons démontré que le TNFα inhibe l’expression du CMH II induit par l’IFNγ sur les ARPE par régulation négative du CIITA (Class II Transactivator). Comme l’activation des lymphocytes T par les cellules de l’EPR dépend de leur niveau d’expression du CMH II, notre étude soutient l’idée que le TNFα possède des propriétés immunomodulatrices sur l’activation de ces cellules, et participe ainsi à la phase de résolution de l’inflammation.

Enfin, nous avons étudié les effets du blocage de l’activation des cellules rétiniennes par l’IFNγ en surexprimant le gène SOCS1 (Suppressor Of Cytokine Signaling) in vivo et in vitro.

Nous avons surexprimé le gène SOCS1 au niveau rétinien et étudier l’effet de cette surexpression sur le développement de l’UAE. L’analyse des grading clinique n’a pas montré de différence significative entre les yeux injectés par l’AAV2-SOCS1 versus l’AAV2-EGFP contrôle. Afin de normaliser par rapport à la diversité inter-individuelle de la maladie, nous avons calculé pour chaque souris un ratio des grades cliniques de l’œil injecté sur l’œil non-injecté. L’analyse de la moyenne de ces ratios montre un effet à la limite de la significativité entre le groupe SOCS1 et le groupe EGFP en terme de grades cliniques. La différence devient par contre significative lorsque l’analyse de ces ratios est faite sur les grades histologiques. Nos expériences mènent donc plutôt à la conclusion que l’expression de SOCS1, médié par injection intravitréenne de l’AAV2 ne protège globalement pas les yeux du développement d’une UAE.

Cette absence d’effet peut avoir comme explication que l’injection intravitréenne conduit à une infection relativement limitée des cellules rétiniennes impliquées dans le développement de l’UAE. Il se pourrait également que le niveau d’expression de la protéine SOCS1 soit trop faible pour obtenir un effet protecteur ou que la surexpression de SOCS1 affecte uniquement l’activation des cellules de la rétine par l’IFNγ mais pas par d’autres cytokines telles le TNFα, l’IL-17, ou l’IL-22 qui jouent aussi un rôle important dans le développement d’UAE. C’est cette dernière hypothèse que nous avons choisi d’investiguer in vitro. Nos résultats montrent que la surexpression de ce même gène SOCS1 dans les cellules d’EPR a un effet inhibiteur sur leur activation par l’IFNγ mais pas par le TNFα.

Ce travail met tout d’abord en évidence l’importante expression, in vivo, de VCAM1 par les cellules de la BHR lors d’UAE et in vitro les effets antagonistes du TNFα et de l’IFNγ sur la régulation de l’expression de molécules du CMHII à la surface de l’EPR. Nos expériences démontrent que la surexpression du gène SOCS1 après injection intravitréenne du vecteur AAV-CAG-SOCS1 n’a que peu d’effet sur le développement de la maladie. Par ailleurs, la surexpression de ce même gène SOCS1 dans les cellules d’EPR a un effet inhibiteur sur leur activation par l’IFNγ mais pas par le TNFα et l’IL-17.

Doctorat en sciences biomédicales
info:eu-repo/semantics/nonPublished

APA, Harvard, Vancouver, ISO, and other styles

40

Chen, F. K. "Retinal pigment epithelium transplantation in retinal diseases." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1318070/.

Full text

Abstract:

Age-related macular degeneration (AMD) and inherited macular diseases (IMD) are retinal disorders that can cause blindness through atrophy of the retinal pigment epithelium (RPE) or choroidal neovascularisation (CNV). RPE transplantation in severe forms of neovascular AMD has been performed with promising short-term outcomes. However, this approach has not been evaluated in atrophic types of AMD or IMD. Furthermore, the long-term outcomes of photoreceptors cell function rescue by RPE reconstruction in neovascular AMD is unknown. Current surgical techniques are complex with associated high complication rates. Therefore, other treatment approaches to reconstruct the RPE are required. This thesis aims to examine whether long-term photoreceptor cell function rescue can be achieved through RPE reconstruction by investigating the outcomes of autologous RPE transplantation or full macular translocation in AMD and IMD. A further aim is to determine the feasibility of a new approach to reconstruct the RPE using human embryonic stem cell (hESC). A prospective study of autologous RPE-choroid grafts in 9 patients with atrophic macular disease secondary to AMD or IMD demonstrated that submacular RPE graft can support retinal function and fixation. However, there was a high surgical and post-operative complication rates and the overall visual acuity and reading ability declined. Long-term follow-up demonstrated that the graft can maintain retinal function for over 2 years in some patients. A retrospective review of long-term outcomes following autologous RPE-choroid grafts and full macular translocation in 12 and 40 patients with neovascular AMD, respectively, showed that rescue of retinal function beyond 2 years is possible. A visual acuity of 6/12 was achieved and maintained for over 2 years in 8% and 15% of patients who had patch graft and translocation, respectively. However, overall visual acuity outcomes were limited by delayed post-operative complications such as recurrent CNV and cystoid macular oedema. A prospective porcine experiment showed that subretinal implant of hESC derived-RPE was feasible and human donor cell can survive in vivo for up to 6 weeks. However, there was significant loss of the hESC-RPE which may have occurred intra-operatively or during the first 2 weeks post-operatively. Macrophages were noted at the site of the graft suggesting some inflammatory and immunological responses to the human cells, polyester substrate or surgical trauma. The work in this thesis has provided the proof of principle that reconstruction of the RPE can maintain retinal function in atrophic and neovascular macular diseases over the long-term. A novel approach using hESC-RPE on an artificial substrate may be a more feasible and safer alternative to current clinical techniques of RPE reconstruction.

APA, Harvard, Vancouver, ISO, and other styles

41

Tretiach, Marina Louise. "Bovine Models of Human Retinal Disease: Effect of Perivascular Cells on Retinal Endothelial Cell Permeability." Thesis, The University of Sydney, 2005. http://hdl.handle.net/2123/1153.

Full text

Abstract:

Background: Diabetic vascular complications affect both the macro- and microvasculature. Microvascular pathology in diabetes may be mediated by biochemical factors that precipitate cellular changes at both the gene and protein levels. In the diabetic retina, vascular pathology is found mainly in microvessels, including the retinal precapillary arterioles, capillaries and venules. Macular oedema secondary to breakdown of the inner blood-retinal barrier is the most common cause of vision impairment in diabetic retinopathy. MÃ¼ller cells play a critical role in the trophic support of retinal neurons and blood vessels. In chronic diabetes, MÃ¼ller cells are increasingly unable to maintain their supportive functions and may themselves undergo changes that exacerbate the retinal pathology. The consequences of early diabetic changes in retinal cells are primarily considered in this thesis. Aims: This thesis aims to investigate the effect of perivascular cells (MÃ¼ller cells, RPE, pericytes) on retinal endothelial cell permeability using an established in vitro model. Methods: Immunohistochemistry, cell morphology and cell growth patterns were used to characterise primary bovine retinal cells (MÃ¼ller cells, RPE, pericytes and endothelial cells). An in vitro model of the blood-retinal barrier was refined by coculturing retinal endothelial cells with perivascular cells (MÃ¼ller cells or pericytes) on opposite sides of a permeable Transwell filter. The integrity of the barrier formed by endothelial cells was assessed by transendothelial electrical resistance (TEER) measurements. Functional characteristics of endothelial cells were compared with ultrastructural morphology to determine if different cell types have barrier-enhancing effects on endothelial cell cultures. Once the co-culture model was established, retinal endothelial cells and MÃ¼ller cells were exposed to different environmental conditions (20% oxygen, normoxia; 1% oxygen, hypoxia) to examine the effect of perivascular cells on endothelial cell permeability under reduced oxygen conditions. Barrier integrity was assessed by TEER measurements and permeability was measured by passive diffusion of radiolabelled tracers from the luminal to the abluminal side of the endothelial cell barrier. A further study investigated the mechanism of laser therapy on re-establishment of retinal endothelial cell barrier integrity. MÃ¼ller cells and RPE, that comprise the scar formed after laser photocoagulation, and control cells (MÃ¼ller cells and pericytes, RPE cells and ECV304, an epithelial cell line) were grown in long-term culture and treated with blue-green argon laser. Lasered cells were placed underneath confluent retinal endothelial cells growing on a permeable filter, providing conditioned medium to the basal surface of endothelial cells. The effect of conditioned medium on endothelial cell permeability was determined, as above. Results: Co-cultures of retinal endothelial cells and MÃ¼ller cells on opposite sides of a permeable filter showed that MÃ¼ller cells can enhance the integrity of the endothelial cell barrier, most likely through soluble factors. Low basal resistances generated by endothelial cells from different retinal isolations may be the result of erratic growth characteristics (determined by ultrastructural studies) or the selection of vessel fragments without true â barrier characteristicsâ in the isolation step. When MÃ¼ller cells were co-cultured in close apposition to endothelial cells under normoxic conditions, the barrier integrity was enhanced and permeability was reduced. Under hypoxic conditions, MÃ¼ller cells had a detrimental effect on the integrity of the endothelial cell barrier and permeability was increased in closely apposed cells. Conditioned medium from long-term cultured MÃ¼ller cells and RPE that typically comprise the scar formed after lasering, enhanced TEER and reduced permeability of cultured endothelial cells. Conclusions: These studies confirm that bovine tissues can be used as a suitable model to investigate the role of perivascular cells on the permeability of retinal endothelial cells. The dual effect of MÃ¼ller cells on the retinal endothelial cell barrier under different environmental conditions, underscores the critical role of MÃ¼ller cells in regulating the blood-retinal barrier in health and disease. These studies also raise the possibility that soluble factor(s) secreted by MÃ¼ller cells and RPE subsequent to laser treatment reduce the permeability of retinal vascular endothelium. Future studies to identify these factor(s) may have implications for the clinical treatment of macular oedema secondary to diseases including diabetic retinopathy.

APA, Harvard, Vancouver, ISO, and other styles

42

Tretiach, Marina Louise. "Bovine Models of Human Retinal Disease: Effect of Perivascular Cells on Retinal Endothelial Cell Permeability." University of Sydney, 2005. http://hdl.handle.net/2123/1153.

Full text

Abstract:

Doctor of Philosophy (Medicine)
Background: Diabetic vascular complications affect both the macro- and microvasculature. Microvascular pathology in diabetes may be mediated by biochemical factors that precipitate cellular changes at both the gene and protein levels. In the diabetic retina, vascular pathology is found mainly in microvessels, including the retinal precapillary arterioles, capillaries and venules. Macular oedema secondary to breakdown of the inner blood-retinal barrier is the most common cause of vision impairment in diabetic retinopathy. MÃ¼ller cells play a critical role in the trophic support of retinal neurons and blood vessels. In chronic diabetes, MÃ¼ller cells are increasingly unable to maintain their supportive functions and may themselves undergo changes that exacerbate the retinal pathology. The consequences of early diabetic changes in retinal cells are primarily considered in this thesis. Aims: This thesis aims to investigate the effect of perivascular cells (MÃ¼ller cells, RPE, pericytes) on retinal endothelial cell permeability using an established in vitro model. Methods: Immunohistochemistry, cell morphology and cell growth patterns were used to characterise primary bovine retinal cells (MÃ¼ller cells, RPE, pericytes and endothelial cells). An in vitro model of the blood-retinal barrier was refined by coculturing retinal endothelial cells with perivascular cells (MÃ¼ller cells or pericytes) on opposite sides of a permeable Transwell filter. The integrity of the barrier formed by endothelial cells was assessed by transendothelial electrical resistance (TEER) measurements. Functional characteristics of endothelial cells were compared with ultrastructural morphology to determine if different cell types have barrier-enhancing effects on endothelial cell cultures. Once the co-culture model was established, retinal endothelial cells and MÃ¼ller cells were exposed to different environmental conditions (20% oxygen, normoxia; 1% oxygen, hypoxia) to examine the effect of perivascular cells on endothelial cell permeability under reduced oxygen conditions. Barrier integrity was assessed by TEER measurements and permeability was measured by passive diffusion of radiolabelled tracers from the luminal to the abluminal side of the endothelial cell barrier. A further study investigated the mechanism of laser therapy on re-establishment of retinal endothelial cell barrier integrity. MÃ¼ller cells and RPE, that comprise the scar formed after laser photocoagulation, and control cells (MÃ¼ller cells and pericytes, RPE cells and ECV304, an epithelial cell line) were grown in long-term culture and treated with blue-green argon laser. Lasered cells were placed underneath confluent retinal endothelial cells growing on a permeable filter, providing conditioned medium to the basal surface of endothelial cells. The effect of conditioned medium on endothelial cell permeability was determined, as above. Results: Co-cultures of retinal endothelial cells and MÃ¼ller cells on opposite sides of a permeable filter showed that MÃ¼ller cells can enhance the integrity of the endothelial cell barrier, most likely through soluble factors. Low basal resistances generated by endothelial cells from different retinal isolations may be the result of erratic growth characteristics (determined by ultrastructural studies) or the selection of vessel fragments without true âbarrier characteristicsâ in the isolation step. When MÃ¼ller cells were co-cultured in close apposition to endothelial cells under normoxic conditions, the barrier integrity was enhanced and permeability was reduced. Under hypoxic conditions, MÃ¼ller cells had a detrimental effect on the integrity of the endothelial cell barrier and permeability was increased in closely apposed cells. Conditioned medium from long-term cultured MÃ¼ller cells and RPE that typically comprise the scar formed after lasering, enhanced TEER and reduced permeability of cultured endothelial cells. Conclusions: These studies confirm that bovine tissues can be used as a suitable model to investigate the role of perivascular cells on the permeability of retinal endothelial cells. The dual effect of MÃ¼ller cells on the retinal endothelial cell barrier under different environmental conditions, underscores the critical role of MÃ¼ller cells in regulating the blood-retinal barrier in health and disease. These studies also raise the possibility that soluble factor(s) secreted by MÃ¼ller cells and RPE subsequent to laser treatment reduce the permeability of retinal vascular endothelium. Future studies to identify these factor(s) may have implications for the clinical treatment of macular oedema secondary to diseases including diabetic retinopathy.

APA, Harvard, Vancouver, ISO, and other styles

43

Stepczynski, Jadwiga Maja. "Defining the molecular phenotype of the rat retina during the commitment phase of light-induced retinal degeneration, a model of human retinal degenerative disease." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60502.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Zhong, Ming. "ABCA4 structure-function relationships : role in Stargardt disease and related retinal degenerative diseases." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/7111.

Full text

Abstract:

ABCA4, also known as ABCR or the rim protein, is a member of the family of ATP binding cassette (ABC) proteins expressed in rod and cone photoreceptors. Mutations in ABCA4 have been linked to Stargardt macular degeneration and related retinal degenerative diseases and implicated in the transport of retinoid compounds across the outer segment disk membrane. This dissertation investigation describes various aspects of the structure and function relationships for ABCA4 and examines the mechanisms by which mutations in ABCA4 lead to various retinal degenerative diseases. A pull-down was employed to identify the retinoid substrate that interacts with ABCA4. When all-trans-retinal was added to ABCA4 in the presence of phosphatidylethanolamine, ~1 mol of N-retinylidene-phosphatidylethanolamine was bound per mol of ABCA4 with an apparent Kd of 5.4 μM. These results provided the first direct biochemical evidence for the identity of the retinoid substrate for ABCA4. To determine the role of that C-terminus of ABCA4 plays in structure and function, a series of deletion and chimera mutants of ABCA4 was expressed, purified by immunoaffinity chromatography, and their biochemical properties analyzed. Removal of the C-terminal 30 amino acids including a conserved VFVNFA motif or substitution of the VFVNFA motif with alanines resulted in the complete loss in N-retinylidene-phosphatidylethanolamine substrate binding, ATP photoaffinity labeling, and retinal stimulated ATPase activity and caused retention of ABCA4 in the endoplasmic reticulum. In contrast mutants lacking the C-terminal 8, 16 or 24 amino acids but retaining the VFVNFA motif were active. These studies indicated that the VFVNFA motif in ABCA4 is required for proper folding of ABCA4 into a functionally active protein. These results provide a molecular rationale for the disease phenotype displayed by individuals with mutations in the C-terminus of ABCA4. Co-IP studies coupled to mass spectrometry were performed to identify novel protein interactors of ABCA4. Rhodopsin and arrestin (including a splice variant of arrestin, p⁴⁴) were identified and confirmed by western blotting. All-trans-retinal was found as a regulator of this interaction. This study for the first time has identified the retinoid substrate for ABCA4, demonstrated a role for the C-terminus and has found protein partners of ABCA4.

APA, Harvard, Vancouver, ISO, and other styles

45

Blixt, Maria. "Keeping up with retinal photoreceptors and horizontal cells : Labelling and mapping of cells in the normal and diseased embryonic chicken retina." Doctoral thesis, Uppsala universitet, Medicinsk utvecklingsbiologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-315655.

Full text

Abstract:

The childhood eye cancer retinoblastoma originates from the retina and its development is initiated while the foetus is in the uterus. Retinoblastoma has a reported incidence of 1 in 15-18 000 live births, and approximately 90% of all patients are diagnosed before the age of 5. The occurrence of retinoblastoma is usually detected by the parents and the most frequent symptoms are leukocoria (white pupillary reflex), strabismus (squinting) or if the child complains of visual problems. Retinoblastoma is diagnosed by examination under anaesthesia and documentation by RetCam. It is treated with various cytostatic agents, or by laser. If the treatment is unsuccessful, or there is a risk that the tumour cells will spread and form metastases, the eye is removed. Previous studies have indicated that the cell type from which the tumour arises, the cell-of-origin, may be the cone photoreceptors and/or their immediate interneuron, the horizontal cells. Determining the cell-of-origin for retinoblastoma is an important goal, however, understanding the molecular mechanisms that distinguish the photoreceptors and the horizontal cells from the other retinal cells may prove just as important for understanding this disease. The aim of my project has been to develop, optimise and validate methods to label, map and target expression to photoreceptors and horizontal cells in the chicken embryonic retina. We have successfully established several methods that test the expression pattern of conserved, regulatory DNA sequences, and have performed short- and long-term expression of various genes that have been reported to be involved in cell cycle regulation and cell fate determination. One of my most important findings was that a region from the RXRγ gene allowed us to specifically target the photoreceptors and horizontal cells. Our previous knowledge, together with the newly established tools, puts us an important step closer towards understanding the development and behaviour of the retinal photoreceptors and horizontal cells, however, further studies are of course needed.

APA, Harvard, Vancouver, ISO, and other styles

46

Leung, Yan-pui Irene. "Potential impact of alzheimer's disease on retina." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42905059.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Sundaram, V. "Gene therapy for inherited retinal diseases." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1418145/.

Full text

Abstract:

Inherited retinal diseases include a number of disorders which typically affect photoreceptor/retinal pigment epithelial function, and can lead to severe visual impairment. Advances in molecular genetics have allowed the identification of many of the genes responsible for particular conditions, and progress in viral gene transfer technology has enabled the replacement of specific genes into the retina. The first human clinical trial of gene therapy for inherited retinal disease was carried out at Moorfields Eye Hospital and UCL Institute of Ophthalmology, involving 12 patients with RPE65 deficiency - an early-onset retinal dystrophy. The results from this trial are described and provide evidence for the safe administration of viral vectors in the eye, and also demonstrate improvements in retinal function in a number of patients. However, the extent and duration of the response did not match that observed in prior animal studies, suggesting improvements in gene expression level may be required in humans. In addition, consideration for future involvement of the foveal region is highlighted, since retinal thinning was observed in a number of patients following subretinal delivery. Achromatopsia is an inherited disorder of congenitally absent cone photoreceptor function. Gene replacement therapy in animal models of achromatopsia has shown evidence of restored cone function, suggesting that this condition may be an appropriate target for gene therapy in humans. Recent studies have suggested that achromatopsia is a progressive condition with deterioration in cone structure with age, implying that the window of opportunity for therapeutic intervention may be narrow. In this study of retinal structure and function (in preparation for a gene therapy trial) in 40 patients with achromatopsia, an age-associated deterioration in cone structure was not identified, suggesting that the age range for potential intervention is wider than recently suggested, and prospective patients should be assessed on an individual basis, irrespective of age.

APA, Harvard, Vancouver, ISO, and other styles

48

Ortuño-Lizarán, Isabel. "Cellular alterations of the human retina in Parkinson’s disease and their use as early biomarkers." Doctoral thesis, Universidad de Alicante, 2019. http://hdl.handle.net/10045/118447.

Full text

Abstract:

En la presente Tesis Doctoral se describen los cambios celulares que ocurren en la retina en la enfermedad de Parkinson y su posible uso como biomarcadores tempranos de la enfermedad. Los pacientes con enfermedad de Parkinson poseen acumulaciones de alfa sinucleína fosforilada en la retina similares a las que se encuentran en el cerebro de los mismos pacientes. De hecho, la cantidad de alfa-sinucleína fosforilada en la retina correlaciona con la cantidad de alfa-sinucleína fosforilada en el cerebro, con el estadio de progresión de la enfermedad y con la severidad de los síntomas motores. Además, en la retina de enfermos de párkinson se describe una degeneración de las células ganglionares melanopsínicas de la retina, lo que podría explicar las alteraciones en los ritmos circadianos y los desórdenes del sueño que aparecen en pacientes. Finalmente, también se muestra la degeneración de las células amacrinas dopaminérgicas, que se reducen en un 45%. Este fallo en el sistema dopaminérgico de la retina provoca alteraciones morfológicas en las células amacrinas AII, sus principales postsinápticas, y podría explicar algunas alteraciones visuales descritas en la enfermedad como la disminución de la sensibilidad al contraste o de la agudeza visual. En global, los resultados muestran que la retina reproduce los procesos degenerativos que ocurren en el cerebro en la enfermedad de Parkinson y, por tanto, que es un tejido idóneo para el estudio de la enfermedad. Además, el estudio de la retina aporta información sobre el estadio de la enfermedad y puede ser empleado como un biomarcador temprano que ayude al diagnóstico y seguimiento de la misma.

APA, Harvard, Vancouver, ISO, and other styles

49

Maghribi, M. "Microfabrication of an Implantable silicone Microelectrode array for an epiretinal prosthesis." Washington, D.C : Oak Ridge, Tenn. : United States. Dept. of Energy ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2003. http://www.osti.gov/servlets/purl/15005780-5uYpbJ/native/.

Full text

Abstract:

Thesis (Ph.D.); Submitted to the Univ. of California, Davis, CA (US); 10 Jun 2003.
Published through the Information Bridge: DOE Scientific and Technical Information. "UCRL-LR-153347" Maghribi, M. 06/10/2003. Report is also available in paper and microfiche from NTIS.

APA, Harvard, Vancouver, ISO, and other styles

50

Gegnaw, Shumet T. "The connection between circadian clock impairment and retinal disease." Electronic Thesis or Diss., Strasbourg, 2023. http://www.theses.fr/2023STRAJ120.

Full text

Abstract:

Cette thèse a étudié comment une dérégulation de l'horloge circadienne, qui n'avait pas été clairement associée à une maladie rétinienne jusqu'à présent, pourrait contribuer à la dégénérescence et influencer le développement et la fonction de la rétine. L'inactivation spécifique du gène horloge Bmal1 (rod-Bmal1KO) dans la lignée de souris portant la mutation P23H de la rhodopsine aggrave les symptômes de dégénérescence rétinienne, tels que la réduction de la réponse ERG et la perte de bâtonnets, induits par la seule mutation P23H. Ces observations ont été corroborées par l'analyse RNA-Seq qui a révélé des changements majeurs dans l'expression des gènes, liés à la phototransduction et aux processus métaboliques, entre le double mutant (rod-Bmal1KO/P23H) et les rétines P23H. Nous avons montré qu'au cours du développement, l’invalidation des gènes horloge Per1 et Per2 chez la souris affecte de manière significative l'expression des gènes de la phototransduction et du cycle cellulaire. Nous avons observé que les souris adultes déficientes en Per1 et Per2 ne modulent pas quotidiennement leur sensibilité à la lumière, dans des conditions scotopiques et mésopiques. Nous avons également constaté une altération de la régulation journalière de la sensibilité à la lumière chez les souris déficientes en gène d'horloge Bmal1 dans les bâtonnets. De plus, nous avons investigué comment la dégénérescence des bâtonnets pourrait influencer la capacité rythmique globale de la rétine en mesurant les rythmes de bioluminescence PER2::LUC chez des souris P23H. Nos résultats montrent que l'horloge rétinienne chez les souris hétérozygotes P23H/+ présente des rythmes circadiens avec une robustesse et une amplitude significativement accrues. Ces effets impliquent probablement l’activation des cellules gliales
This thesis investigated how circadian clock misregulation, which has not been clearly associated with retinal genetic disease so far, could contribute to degeneration and influence development and function in the retina. The rod-specific knockout of Bmal1 clock gene (rod-Bmal1KO) from the mouse line carrying the P23H mutation of rhodopsin exacerbated the retinal degeneration phenotypes, such as reduction in ERG response and rods loss, induced by the P23H mutation alone. These observations were corroborated by RNA-Seq analysis, where we found major changes in expression of genes related to phototransduction and metabolic processes, between the (rod-Bmal1KO/P23H) double mutant and P23H retinas. We showed that during development, Per1 and Per2 clock genes deficiency in mice significantly affects gene expression of phototransduction and cell cycle components. We found that adult mice deficient for Per1 and Per2 genes lack a daily modulation of light sensitivity, under scotopic and mesopic conditions. We also found an impaired daily modulation of light sensitivity in mice deficient for Bmal1 clock gene in rods. Additionally, we investigated how rod degeneration could impact on the global rhythmic capacity of the retina by measuring PER2::LUC bioluminescence rhythms in P23H mice. We showed that the retinal clock in P23H/+ heterozygous mice displays circadian rhythms with significantly increased robustness and amplitude. These effects likely involve activation of glial cells

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Retina Diseases'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles