Search results for "Retina"
showing 10 items of 864 documents
gamma-Aminobutyric acid type A/benzodiazepine receptors regulate rat retina neurosteroidogenesis.
1995
Abstract It has been previously shown that retinal ganglion cells have the ability to synthesize steroids including neuroactive steroids such as pregnenolone sulfate. Since ganglion cells possess GABAA/benzodiazepine (BZ) receptors and neurosteroids modulate retinal GABAA receptor function, we investigated the role of these receptors in isolated rat retina neurosteroidogenesis. Ligands for central-type BZ receptors stimulated retinal pregnenolone synthesis. Clonazepam was the most potent ligand examined acting at nanomolar concentrations. Moreover, the effective steroidogenesis stimulatory dose (ED50) for these ligands and theKi to inhibit [3-H]flunitrazepam binding showed a coefficient of …
Pregnenolone sulfate, a naturally occurring excitotoxin involved in delayed retinal cell death.
2002
The present study was designed to investigate the neurosteroid pregnenolone sulfate (PS), known for its ability to modulate NMDA receptors and interfere with acute excitotoxicity, in delayed retinal cell death. Three hours after exposure of the isolated and intact retina to a 30-min PS pulse, DNA fragmentation as assessed by genomic DNA gel electrophoresis and a modified in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method appeared concurrently with an increase in superoxide dismutase (SOD) activity and thiobarbituric acid-reactive substances (TBARS) levels. At 7 h, the increased amount of DNA laddering was accompanied by a higher number of TUN…
Transcriptional regulation of nucleoredoxin-like genes takes place on a daily basis in the retina and pineal gland of rats.
2015
AbstractThe nucleoredoxin-like gene Nxnl1 (Txnl6) and its paralogue Nxnl2 encode the rod-derived cone viability factors (RdCVF and RdCVF2), which increase the resistance to photooxidative damage and have therapeutic potential for the survival of cones in retinitis pigmentosa. In this study, the transcription of Nxnl genes was investigated as a function of the day/night cycle in rats. The transcript levels of Nxnl1 and Nxnl2 were seen to display daily rhythms with steadily increasing values during the light phase and peak expression around dark onset in preparations of whole retina, photoreceptor cells and—but only in regard to Nxnl1—in photoreceptor-related pinealocytes. The cycling of Nxnl…
PHOTODYNAMIC THERAPY WITH VERTEPORFIN FOR CHOROIDAL NEOVASCULARIZATION ASSOCIATED WITH RETINAL PIGMENT EPITHELIAL DETACHMENT IN AGE-RELATED MACULAR D…
2007
Abstract PURPOSE: To assess the effectiveness of photodynamic therapy (PDT) with verteporfin for choroidal neovascularization (CNV) associated with retinal pigment epithelium detachment (PED) in age-related macular degeneration. METHODS: Thirty eyes of 26 patients with CNV and PED were treated with PDT. The eyes were divided in two groups based on CNV location in relation to PED; group 1 included 13 eyes with CNV within PED, and group 2 included 17 eyes with CNV at the edge of PED. The median follow-up was 16 months. RESULTS: Patients received a mean +/- SD of 2.83 +/- 1.26 treatments (range, 1-6 treatments). In the whole cohort, the mean preoperative visual acuity changed from 20/144 (0.86…
Local safety of repeated intravitreal Ozurdex
2013
Sir, The article entitled ‘Twelve-month experience with Ozurdex for the treatment of macular edema associated with retinal vein occlusion'1 highlights the significant cataract progression in eyes receiving more than one Ozurdex implant. We retrospectively reviewed the charts of all patients with macular edema secondary to retinal vein occlusion (RVO) refractory to current therapies and treated with Ozurdex from April 2010 until March 2012. The mean age of patients with branch RVO (n=33) was 72.4. In eyes receiving a second Ozurdex implant, four out of the five phakic eyes showed progression of cataract requiring surgery. We registered one case of anterior chamber migration resulting in a bu…
Effect of head position on refraction in aphakic and phakic silicone-filled eyes.
1997
BACKGROUND The refraction of the eye is altered significantly after the instillation of silicone oil into the vitreous cavity because of the silicone oil's high refractive index. The degree of the refractive change shows diurnal variation and depends on the patient's head position. PATIENTS AND METHODS To analyze the degree and time course of refractive changes with respect to head position, the authors performed objective refraction in five aphakic and five phakic silicone oil-instilled eyes with attached maculae using an automatic hand-held refractometer. In each patient, 25 measurements were taken at short intervals using a hand-held autorefractometer with the patient in different positi…
Visual evoked potentials in insulin-dependent diabetics
1985
The latency of pattern-reversal VEPs was studied in type I insulin-dependent diabetics without retinal and extraocular involvement. One hundred eyes of 50 diabetics (mean age 19.8 +/- 7.2 years) formed the study group; the duration of the disease ranged between 1 month and 15 years. The latencies of VEPs were progressively delayed in relation to the duration of the disease, becoming more and more evident and stabilizing after about 6 years from the onset of diabetes. The VEP alterations probably indicate alteration of membrane balance or demyelinization.
Photoreactive flow changes in the posterior cerebral artery in control subjects and patients with occipital lobe infarction.
1995
Background and Purpose Photoreactive flow changes of the posterior cerebral artery (PCA) in control subjects and patients with unilateral occipital lobe infarction were investigated to study the hypothesis that occipital lobe infarction of varying extent leads to a reduced visually activated flow increase in the ipsilateral PCA. Methods Maximum mean flow velocity (MFV) of the PCA was investigated by transcranial Doppler sonography after photic stimulation of the retina. Results In 25 control subjects MFV was increased by 30.6±9.7%. In 13 patients with unilateral occipital lobe infarction the ipsilateral MFV increase was significantly lower than in control subjects. Nine patients with homon…
Subretinal neovascularization in anterior ischemic optic neuropathy.
1991
A 66-year-old man with typical anterior ischemic optic neuropathy in one eye suffered from edema of the optic disc without functional changes in the fellow eye. However, 7 months later, a reduction in visual acuity, a change in the visual field and a worsening of the contrast-sensitivity curve demonstrated the development of typical anterior ischemic optic neuropathy in this eye as well. After another 6-month period, in addition to these changes, an extensive subretinal neovascular membrane developed in the papillomacular area, which further reduced the patient's visual acuity and required treatment with laser photocoagulation. To our knowledge, this is the first case report of the occurren…
ANATOMICAL AND FUNCTIONAL OUTCOMES OF SYMPTOMATIC IDIOPATHIC VITREOMACULAR TRACTION
2016
To describe the natural history of eyes with symptomatic idiopathic vitreomacular traction (VMT).Retrospective multicenter study of 168 eyes with spectral-domain optical coherence tomography (SD-OCT) findings consistent with idiopathic VMT. All eyes were graded according to SD-OCT findings. Grade 1 was defined as incomplete cortical vitreous separation with foveal attachment. Grade 2 was defined as Grade 1 plus intraretinal cysts or clefts. Grade 3 was defined as Grade 2 plus a foveal detachment. All patients were followed for at least 6 months.There were 168 patients (51 men) with a mean age of 68.8 ± 10.7 years. Patients were followed for a mean of 22.7 ± 20.1 months. The mean duration of…