Search results for "Retinal ganglion cell"
showing 8 items of 68 documents
Magnetic resonance imaging and optical coherence tomography correlations in multiple sclerosis beyond anatomical landmarks.
2020
Abstract Objective To investigate multiple sclerosis (MS) optical coherence tomography (OCT) cross-sectional correlations with central nervous system (CNS) magnetic resonance imaging (MRI). Material and methods Peripapillary retinal nerve fiber layer (pRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner (INL) and outer nuclear layer (ONL) of 54 relapsing remitting (RRMS) and 38 progressive (PMS, 9 primary and 29 secondary) patients were measured. With less than 3 months brain parenchymal fraction (BPF), spinal cord (SC), total gray matter (GM) and white matter volumes were calculated. Demographical and clinical data was compared according to the history of optic neuritis (H…
p27Kip1participates in the regulation of endoreplication in differentiating chick retinal ganglion cells
2015
Nuclear DNA duplication in the absence of cell division (i.e. endoreplication) leads to somatic polyploidy in eukaryotic cells. In contrast to some invertebrate neurons, whose nuclei may contain up to 200,000-fold the normal haploid DNA amount (C), polyploid neurons in higher vertebrates show only 4C DNA content. To explore the mechanism that prevents extra rounds of DNA synthesis in these latter cells we focused on the chick retina, where a population of tetraploid retinal ganglion cells (RGCs) has been described. We show that differentiating chick RGCs that express the neurotrophic receptors p75 and TrkB while lacking retinoblastoma protein, a feature of tetraploid RGCs, also express p27K…
Dynamics, alterations, and consequences of minimally invasive intraocular pressure elevation in rats.
2014
PURPOSE: An important, yet not exclusive, aspect of primary open angle glaucoma is elevated intraocular pressure (IOP) profiles within fluctuations and pressure peaks. The study aimed at establishing minimally invasive methods for recurrent IOP elevation in rats to investigate the impact of IOP dynamics and pathomorphologic retinal alterations during and after IOP elevation. METHODS: Intraocular pressure was elevated unilaterally in Long Evans rats to a level of ≈35 mm Hg for 1 hour in a total of 30 manipulations within 6 weeks, by using two methods: (1) suction-cup oculopression and (2) loop-adjusted oculopression. Retinal thickness (RT) was measured via optical coherence tomography (OCT),…
Retinal neurodegenerative changes in the adult insulin receptor substrate-2 deficient mouse.
2014
Abstract Insulin receptor substrate-2 (Irs2) mediates peripheral insulin action and is essential for retinal health. Previous investigations have reported severe photoreceptor degeneration and abnormal visual function in Irs2-deficient mice. However, molecular changes in the Irs2 − / − mouse retina have not been described. In this study, we examined retinal degenerative changes in neuronal and glial cells of adult (9- and 12-week old) Irs2 − / − mice by immunohistochemistry. 9-week old Irs2 − / − mice showed significant thinning of outer retinal layers, concomitant to Muller and microglial cell activation. Photoreceptor cells displayed different signs of degeneration, such as outer/inner…
Fiat lux: the light became therapy. An overview on the Bright Light Therapy in Alzheimer’s Disease sleep disorders
2020
Background: A system of photosensitive retinal ganglion cells provides ‘non-visual’ information on the circadian sequences of light to the suprachiasmatic nucleus (SCN), which, as the ‘master clock’, synchronizes the chronobiological mechanisms of all the biological clocks. Damage to SCN structure alters circadian behavioral and hormonal rhythms and interferes with a regular sleep-wake pattern. Several studies have shown that, in aging and in Alzheimer’s disease (AD), circadian rhythms change their synchronization with the environment and behavior loses sync with light. Objective: The current overview aims to examine research studies showing the effect of bright light therapy (BLT) on sleep…
In vivo consequences of cholesterol-24s-hydroxylase (CYP46A1) inhibition by voriconazole on cholesterol homeostasis and function in the rat retina
2011
Cholesterol 24S-hydroxylase (CYP46A1) converts cholesterol into 24S-hydroxycholesterol in neurons and participates in cholesterol homeostasis in the central nervous system, including the retina. We aimed to evaluate the consequences of CYP46A1 inhibition by voriconazole on cholesterol homeostasis and function in the retina. Rats received daily intraperitoneal injections of voriconazole (60mg/kg), minocycline (22mg/kg), voriconazole plus minocycline, or vehicle during five consecutive days. The rats were submitted to electroretinography to monitor retinal functionality. Cholesterol and 24S-hydroxycholesterol were measured in plasma, brain and retina by gas chromatography-mass spectrometry. T…
Elevated intraocular pressure induces neuron-specific β-III-tubulin expression in non-neuronal vascular cells.
2019
Purpose Pathological alterations within optic nerve axons and progressive loss of the parental retinal ganglion cell (RGC) bodies are characteristics of glaucomatous neuropathy. Abnormally elevated intraocular pressure (IOP) is thought to be the major risk factor for most forms of glaucomatous changes, while lowering of the IOP is the mainstream of treatment. However, the pathophysiological mechanisms involved in neurodegenerative changes are poorly understood. It remains still a matter of debate whether elevated IOP harms the neurons directly or indirectly through alterations in the retinal vascularization. Methods We analysed morphological and molecular changes within the retina exposed t…
Effect of dietary omega-3 and omega-6 fatty acids on IOP elevation, electroretinographic changes and retinal ganglion cell loss in a rat model of gla…
2008
Purpose To test the efficacy of dietary omega-3 and omega-6 fatty acids in a rat model of glaucoma induced by laser photocoagulation. Methods Rats were fed for 3 months with a diet containing either: 1) 17% of omega-3 fatty acids (10% EPA + 7% DHA), 2) 10% of omega-6 fatty acids (as GLA), or 3) a combination of both omega-3 and omega-6 fatty acids (10% EPA + 7% DHA + 10% GLA), by comparison with a control group of animals fed with a standard diet deprived of EPA, DHA and GLA. After 3 months of diet, glaucoma was induced in one eye of the animal by laser.IOP was regularly measured and the retinal function was evaluated by electroretinography (ERG) for 3 months. At the end of the experiment, …