Search results for "Retina"
showing 10 items of 864 documents
Plasmalogen metabolism in retinal glial cells : interaction between cells during normal or pathological vascular development
2017
Retinal vascular disorders such as retinopathy of prematurity (ROP), diabetic retinopathy or age-related macular degeneration represent the first cause of vision loss at all ages in industrialized countries. Many epidemiological or animal studies have shown the involvement of polyunsaturated fatty acids (PUFA) in the regulation of vascular development and more specifically the beneficial properties of omega 3 PUFA (n-3 PUFA) against pathological vascularization. Those PUFA are esterified on glycerophospholipids (GP). GP are the primary constituents of the lipid bilayer of cell membranes. PUFA can be also esterified on a specific class of GP, called plasmalogens. Plasmalogens are characteriz…
Effect of intravitreal injection of Indocyanine Green, Triamcinolone Acetonide and Trypan Blue on the electroretinographic response of rats
2007
International audience; Purpose:: Indocyanine Green (ICG) and Tripan Blue (TB) are commonly used in macular surgery by making easier the internal limiting membrane (ILM) removing. However, the innocuousness of these dyes is not actually established notably for ICG. Then, several authors proposed the use of triamcinolone acetonide (TA) as an alternative to the use of intraoperative dyes for visualizing the ILM. The purpose of this study was to evaluate the effects of intravitreal injection of ICG, TB and TA on the rat electroretinogram (ERG). Methods:: Three groups of 12-week-old Sprague Dawley rats (n=6) received intravitreal injection in one eye of 0.1mL of either ICG 0.5mg/mL, TB 3mg/mL o…
Assessment of the toxicity of cholesterol oxides on retinal pigment epithelial cultured cells
2006
International audience; Purpose: Among the retinal lipid deposits found in AMD (age related macular degeneration), esterified and unesterified cholesterol have been identified. Cholesterol that accumulates in Bruch's membrane could be oxidized and lead to cholesterol oxides known as oxysterols. These compounds have cytotoxic activities on many vascular cell types, and we conducted this study to evaluate the cytotoxics effects of oxysterols on retinal pigment epithelial (RPE) cells. Methods: Human RPE cells (ARPE–19) were cultured and treated by 7–ketocholesterol (7–keto), 7–betahydroxycholesterol (7–beta) and 25–hydroxycholesterol (25–OH). ARPE–19 cells viability was determined with MTT ana…
Could pupil dilation measurements be of any help to sensory analysis?
2011
Could pupil dilation measurements be of any help to sensory analysis?. 29. Pupil colloquium
A factor derived from chick embryo retina which inhibits DNA synthesis of retina itself.
1992
Chick embryo retinas contain a peptide factor that inhibits DNA synthesis in explants of chick embryo retina. The inhibitory factor, obtained by acid/ethanol extraction from 15-day-old chick embryo retinas, was partially purified by affinity chromatography on heparin-sepharose CL-6B and gel filtration on Sephadex G-100. The inhibitor reduced DNA synthesis with maximal effects observed in retinal explants from 7 to 8-day-old chick embryos. The inhibitory effect became apparent after 10 h of incubation and reached the maximum levels after 16 h. DNA-inhibiting activity was heat and acid-stable and was destroyed by trypsin and alkaline treatments. The inhibitory effect was observed in retinal e…
Neuroglobin, cytoglobin, and a novel, eye-specific globin from chicken
2004
Neuroglobin and cytoglobin are two recently discovered respiratory proteins of vertebrates. Here we report the first identification and expression analyses of these proteins in bird species. Neuroglobin from the domestic chicken Gallus gallus differs in approximately 30% from the mammalian proteins, but its genome structure shows the conservation of the B12.2, E11.0, and G7.0 intron positions. The chicken cytoglobin protein is shorter than the mammalian orthologs, from which it differs overall by approximately 25%, due to the absence of the C-terminal exon in the gene. Comparison of chicken and mammalian gene order shows that neuroglobin and cytoglobin are located on conserved syntenic chro…
Retinoid dynamics in chicken eye during pre- and postnatal development.
1994
Changes in the steady state level of retinols, retinaldehydes and retinyl esters in the trans and 11-cis forms and trans retinoic acid were measured in whole chicken eye during development from day 6 in ovo to day 3 post-hatch. These retinoids, quantified by different HPLC systems, were detected in this time sequence: trans-retinol and trans-retinyl esters in the first week in ovo, 11-cis-retinol in the second week. The highest level of 11-cis-retinaldehyde and 11-cis-retinyl esters was reached at the end of development in ovo; however, their levels increased further after hatching. The retinoic acid level decreased at the end of the first week, rising again at the end of the second week. T…
Glaucoma and Antioxidants: Review and Update
2020
Glaucoma is a neurodegenerative disease characterised by the progressive degeneration of retinal ganglion cells. Oxidative stress has been related to the cell death in this disease. Theoretically, this deleterious consequence can be reduced by antioxidants substances. The aim of this review is to assemble the studies published in relation to antioxidant supplementation and its effects on glaucoma and to offer the reader an update on this field. With this purpose, we have included studies in animal models of glaucoma and clinical trials. Although there are variable results, supplementation with antioxidants in glaucoma may be a promising therapy in glaucoma.
Retinal Vibrations in Bacteriorhodopsin are Mechanically Harmonic but Electrically Anharmonic: Evidence From Overtone and Combination Bands
2021
Fundamental vibrations of the chromophore in the membrane protein bacteriorhodopsin (BR), a protonated Schiff base retinal, have been studied for decades, both by resonance Raman and by infrared (IR) difference spectroscopy. Such studies started comparing vibrational changes between the initial BR state (all-trans retinal) and the K intermediate (13-cis retinal), being later extended to the rest of intermediates. They contributed to our understanding of the proton-pumping mechanism of BR by exploiting the sensitivity of fundamental vibrational transitions of the retinal to its conformation. Here, we report on new bands in the 2,500 to 1,800 cm−1 region of the K-BR difference FT-IR spectrum.…
Pattern of polyamines and related monoacetyl derivatives in chick embryo retina during development.
1994
Polyamines and related monoacetyl derivatives were studied in chick embryo retina during development (6th-19th day). Putrescine, which is high in the first phase of retinogenesis, is necessary to sustain both tissue proliferation and via N-acetylputrescine, gamma-aminobutyric acid synthesis. A later increase in spermidine and particularly spermine may play a role in the last phase of development when the retina reaches maturation. The presence of N1-acetylspermidine already at the 8th day indicates that in chick embryo retina, putrescine synthesis can depend on two separate pathways. The first involves ornithine decarboxylase activity; the second, spermidine/spermine N1-acetyltransferase an…