Search results for " RETINA"
showing 10 items of 148 documents
Differential Expression of the Demosponge (Suberites domuncula) Carotenoid Oxygenases in Response to Light: Protection Mechanism Against the Self-Pro…
2012
The demosponge Suberites domuncula has been described to contain high levels of a proteinaceous toxin, Suberitine, that displays haemolytic activityIn the present study this 7–8 kDa polypeptide has been isolated and was shown to exhibit also cytotoxic effects on cells of the same species. Addition of retinal, a recently identified metabolite of β-carotene that is abundantly present in S. domuncula was found to reduce both the haemolytic and the cell toxic activity of Suberitine at a molar ratio of 1:1. Spectroscopic analyses revealed that the interaction between β-carotene and Suberitine can be ascribed to a reversible energy transfer reaction. The enzyme that synthesises retinal in the spo…
A visual framework to create photorealistic retinal vessels for diagnosis purposes
2020
The methods developed in recent years for synthesising an ocular fundus can be been divided into two main categories. The first category of methods involves the development of an anatomical model of the eye, where artificial images are generated using appropriate parameters for modelling the vascular networks and fundus. The second type of method has been made possible by the development of deep learning techniques and improvements in the performance of hardware (especially graphics cards equipped with a large number of cores). The methodology proposed here to produce high-resolution synthetic fundus images is intended to be an alternative to the increasingly widespread use of generative ad…
Preoperative, Intraoperative and Postoperative Corticosteroid Use as an Adjunctive Treatment for Rhegmatogenous Retinal Detachment
2020
The treatment for rhegmatogenous retinal detachment (RRD) is surgery, including pars plana vitrectomy (PPV) and scleral buckling (SB). Despite surgical advances, degeneration of the photoreceptors and post-operative complications, such as proliferative vitreoretinopathy (PVR), often occurs as the result of inflammation, preventing complete visual recovery or causing RRD recurrence. There is increasing evidence that in the presence of RRD, the activation of inflammatory processes occurs and the surgery itself induces an inflammatory response. This comprehensive review focuses on the use of different formulations of corticosteroids (CCS), as an adjunctive treatment to surgery, either PPV or S…
Vascular changes after vitrectomy for rhegmatogenous retinal detachment: optical coherence tomography angiography study
2020
Purpose: To analyse the postoperative foveal avascular zone (FAZ) area, superficial vessel density (SVD) and deep vessel density (DVD) and their correlation with functional (best-corrected visual acuity, BCVA) and anatomical outcomes (foveal macular thickness, FMT) after surgery for rhegmatogenous retinal detachment (RRD) repair. Method: Patients with RRD eyes, successfully treated with a single pars plana vitrectomy (PPV) with gas tamponade and a minimum 12 months follow-up, were re-examined. Foveal avascular zone (FAZ) area, SVD, DVD and FMT were evaluated by using optical coherence tomography angiography (OCTA) and compared to fellow eye. Results: Fifty-six patients with macula-on and 37…
Retinal detachment with spontaneous dialysis of the ora serrata in a 13-year-old child with neurofibromatosis type 1: a case report.
2020
A 13‑year‑old child diagnosed with neurofibromatosis type 1 who on a routine control presented with rhegmatogenous retinal detachment associated to dialysis of the ora serrata in the left eye (OS). There were no clinical signs or history of contuse ocular trauma. Neurofibromatosis produces alterations in fibroblasts of the cortex of the vitreous base. This results in deficient production of the collagen fibers that anchor the vitreous base to the pars plana and the peripheral neurosensory retina. Thus, suboptimal function of the fibroblasts explains spontaneous avulsion of the vitreous base. Such avulsion in turn is related to dialysis of the ora serrata.
Kyrieleis´ vasculitis in acute retinal necrosis
2010
Ester Francés-Muñoz1, Roberto Gallego-Pinazo1, Ruth López-Lizcano1, Salvador García-Delpech1, J Luis Mullor3, Manuel Díaz-Llopis1,21Department of Ophthalmology, Hospital La Fe, Valencia, Spain; 2University of Valencia, Valencia, Spain; 3Unit of Experimental Ophthalmology. Fundación para la Investigación del Hospital Universitario La Fe. Valencia, Valencia, SpainAbstract: We report the first case in the literature of Kyrieleis´ vasculitis related to acute retinal necrosis by Varicella zoster virus in a 76-year-old woman with bilateral involvement. In our patient the arterial lesions appeared 15 days after …
Ultrastructural study of primary canine and human pigmentary retinopathy
1985
An electron microscopic study was performed on eyes of Labrador dogs afflicted with progressive retinal atrophy (PRA). There was complete loss of photoreceptors, atrophy of the remaining retina and gliosis in the peripheral part while the central retina showed incomplete loss of photoreceptors and an almost total disappearance of photoreceptor outer segments. Melanin-bearing cells, largely containing melanolysosomes, were found deep inside the retina. This electron microscopic study also incorporated the retina of a middle-aged woman affected by retinopathia pigmentosa (RP). The fine structure of the diseased retina showed a similar pattern of lesions, more pronounced in the periphery of th…
Correlation Between Ischemic Retinal Accidents and Radial Peripapillary Capillaries in the Optic Nerve Using Optical Coherence Tomographic Angiograph…
2017
Background: Perfusion of the optic nerve has been widely studied using fluorescein angiography (FAG), which is currently regarded as the criterion standard. However, FAG has adverse effects associated with intravenous contrast administration and is limited in its capacity to characterize and stratify the different vascular layers of the optic nerve and retina. The use of new imaging techniques, such as optical coherence tomographic angiography (Angio-OCT), is therefore important. Aim: A qualitative description is made of the vascular layers of the optic nerve and of how vascular events affect radial peripapillary capillaries (RPC). Two patients with central retinal artery occlusion (CRAO), …
Photoreceptor vitality in organotypic cultures of mature vertebrate retinas validated by light-dependent molecular movements
2006
AbstractVertebrate photoreceptor cells are polarized neurons highly specialized for light absorption and visual signal transduction. Photoreceptor cells consist of the light sensitive outer segment and the biosynthetic active inner segment linked by a slender connecting cilium. The function of mature photoreceptor cells is strictly dependent on this compartmentalization which is maintained in the specialized retinal environment. To keep this fragile morphologic and functional composition for further cell biological studies and treatments we established organotypic retina cultures of mature mice and Xenopus laevis. The organotypic retina cultures of both model organisms are created as co-cul…
Unsupervised recognition of retinal vascular junction points.
2014
Landmark points in retinal images can be used to create a graph representation to understand and to diagnose not only different pathologies of the eye, but also a variety of more general diseases. Aim of this paper is the description of a non-supervised methodology to distinguish between bifurcations and crossings of the retinal vessels, which can be used in differentiating between arteries and veins. A thinned representation of the binarized image, is used to identify pixels with three or more neighbors. Junction points are classified into bifurcations or crossovers according to their geometrical and topological properties. The proposed approach is successfully compared with the state-of-t…