Search results for "Retina"
showing 10 items of 864 documents
The giant spectrin βV couples the molecular motors to phototransduction and Usher syndrome type I proteins along their trafficking route.
2013
International audience; Mutations in the myosin VIIa gene cause Usher syndrome type IB (USH1B), characterized by deaf-blindness. A delay of opsin trafficking has been observed in the retinal photoreceptor cells of myosin VIIa-deficient mice. We identified spectrin bV, the mammalian b-heavy spectrin, as a myosin VIIa-and rhodopsin-interacting partner in photoreceptor cells. Spectrin bV displays a polarized distribution from the Golgi apparatus to the base of the outer segment, which, unlike that of other b spectrins, matches the trafficking route of opsin and other phototransduction proteins. Formation of spectrin bV-rhodopsin complex could be detected in the differentiating photoreceptors a…
VAMPIRE: Vessel assessment and measurement platform for images of the REtina
2011
We present VAMPIRE, a software application for efficient, semi-automatic quantification of retinal vessel properties with large collections of fundus camera images. VAMPIRE is also an international collaborative project of four image processing groups and five clinical centres. The system provides automatic detection of retinal landmarks (optic disc, vasculature), and quantifies key parameters used frequently in investigative studies: vessel width, vessel branching coefficients, and tortuosity. The ultimate vision is to make VAMPIRE available as a public tool, to support quantification and analysis of large collections of fundus camera images.
Optical Quality Comparison of Conventional and Hole-Visian Implantable Collamer Lens at Different Degrees of Decentering
2012
To compare the optical quality of implantable Collamer lens (ICL) with and without central hole (Hole ICL and conventional ICL) at different degrees of decentering.Experimental laboratory investigation.Wavefront aberrations of the -3, -6, and -12 diopter (D) V4b and -3, -6, and -12 D V4c ICLs were measured in 3 conditions-centered and decentered 0.3 and 0.6 mm-at 3-mm and 4.5-mm pupils. The root mean square of total higher order aberrations, trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. In addition, point spread function and simulated retinal images of ICLs were calculated from the wavefront aberrations for each ICL and all conditions of decenteri…
Intraflagellar transport proteins in ciliogenesis of photoreceptor cells
2011
Background information. The assembly and maintenance of cilia depend on IFT (intraflagellar transport) mediated by molecular motors and their interplay with IFT proteins. Here, we have analysed the involvement of IFT proteins in the ciliogenesis of mammalian photoreceptor cilia. Results. Electron microscopy revealed that ciliogenesis in mouse photoreceptor cells follows an intracellular ciliogenesis pathway, divided into six distinct stages. The first stages are characterized by electron-dense centriolar satellites and a ciliary vesicle, whereas the formations of the ciliary shaft and the light-sensitive outer segment discs are features of the later stages. IFT proteins were associated with…
Human brain organoids assemble functionally integrated bilateral optic vesicles
2021
During embryogenesis, optic vesicles develop from the diencephalon via a multistep process of organogenesis. Using induced pluripotent stem cell (iPSC)-derived human brain organoids, we attempted to simplify the complexities and demonstrate formation of forebrain-associated bilateral optic vesicles, cellular diversity, and functionality. Around day 30, brain organoids attempt to assemble optic vesicles, which develop progressively as visible structures within 60 days. These optic vesicle-containing brain organoids (OVB-organoids) constitute a developing optic vesicle's cellular components, including primitive corneal epithelial and lens-like cells, retinal pigment epithelia, retinal progeni…
Carbonic anhydrase inhibitor with topical NSAID therapy to manage cystoid macular edema in a case of gyrate atrophy
2017
Purpose Gyrate atrophy of the choroid and retina (GACR) is a rare chorioretinal dystrophy characterized by a deficiency of the enzyme ornithine aminotransferase, inherited in an autosomal recessive pattern. Case Report We report a case of a 17-year-old girl with GACR, for whom the level of serum ornithine had been reduced by an arginine-restricted diet. The patient was responsive to an association of topical nonsteroidal anti-inflammatory drugs (NSAIDs) and a carbonic anhydrase inhibitor (CAI) to reduce cystoid macular edema (CME). Conclusions The efficacy of topical NSAIDs and systemic CAI association indicates that the imbalance in the distribution of retinal pigment epithelium membrane-b…
Biological Causes of Anterior Knee Pain
2012
We review the pathophysiology of anterior knee pain in the young patient. Emphasis is placed on newer findings. We have developed what we call the “Neural Model” as an explanation for the genesis of anterior knee pain. We have demonstrated a neuroanatomical basis for PFPS in the young patient and the clinical observation that the lateral retinaculum may have a key role in the origin of this pain. According to our studies we hypothesize that periodic short episodes of ischemia in the lateral retinaculum could be implicated in the pathogenesis of anterior knee pain, at least in a subgroup of anterior knee pain patients, by triggering neural proliferation of nociceptive axons (substance P posi…
Intravitreal delivery of AAV-NDI1 provides functional benefit in a murine model of Leber hereditary optic neuropathy.
2012
Leber hereditary optic neuropathy (LHON) is a mitochondrially inherited form of visual dysfunction caused by mutations in several genes encoding subunits of the mitochondrial respiratory NADH-ubiquinone oxidoreductase complex (complex I). Development of gene therapies for LHON has been impeded by genetic heterogeneity and the need to deliver therapies to the mitochondria of retinal ganglion cells (RGCs), the cells primarily affected in LHON. The therapy under development entails intraocular injection of a nuclear yeast gene NADH-quinone oxidoreductase (NDI1) that encodes a single subunit complex I equivalent and as such is mutation independent. NDI1 is imported into mitochondria due to an e…
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…