Investigative ophthalmology & visual science
-
Invest. Ophthalmol. Vis. Sci. · Apr 2005
CNTF and BDNF have similar effects on retinal ganglion cell survival but differential effects on nitric oxide synthase expression soon after optic nerve injury.
To investigate the effect of ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) on retinal ganglion cell (RGC) survival and nitric oxide synthase (NOS) expression in the retina during the early phase of optic nerve (ON) injury, and to examine whether intraperitoneal application of the NOS scavenger nitro-l-arginine (l-NA) could protect the injured RGCs. ⋯ Both CNTF and BDNF protected RGCs after ON injury. CNTF and BDNF acted differently on NOS expression in the GCL. Intraperitoneal injections of l-NA at appropriate dosages enhance RGC survival.
-
Invest. Ophthalmol. Vis. Sci. · Jan 2005
Changes in mechanical, chemical, and thermal sensitivity of the cornea after topical application of nonsteroidal anti-inflammatory drugs.
In addition to their well-known anti-inflammatory actions, some of the nonsteroidal anti-inflammatory drugs (NSAIDs) appear to have an analgesic effect. In human subjects, the changes in threshold and intensity of sensations evoked by mechanical, chemical, and thermal stimulation of the cornea induced by topical administration of two commercial NSAIDs, diclofenac sodium (Voltaren; Novartis, Basel, Switzerland) and flurbiprofen (Ocuflur; Allergan, Irvine, CA), were studied. ⋯ Flurbiprofen had a very limited effect on sensations evoked by corneal stimulation, whereas diclofenac reduced the intensity of sensations evoked by stimuli of different modality, suggesting a mild local anesthetic effect of this drug on all types of corneal sensory fibers. Such anesthetic action could explain the analgesic effect that has been reported after topical application of diclofenac in inflamed human eyes.
-
Invest. Ophthalmol. Vis. Sci. · Oct 2004
Reading performance in patients with retinitis pigmentosa: a study using the MNREAD charts.
To evaluate the relationship between reading performance and severity of disease in patients with retinitis pigmentosa (RP), assessed with routine clinical psychophysical visual tests. ⋯ The reading performance of most patients with RP is only moderately impaired. It correlates with contrast sensitivity, visual acuity, and visual field. It should be assessed in all cases, as disability can ensue, even when visual acuity is preserved. In patients with RP with poor reading performance, there is little potential for high-magnification devices because visual field constriction affects the reading rate.
-
Invest. Ophthalmol. Vis. Sci. · Oct 2004
Phosphatidylinositol 3-kinase (PI-3K)/Akt but not PI-3K/p70 S6 kinase signaling mediates IGF-1-promoted lens epithelial cell survival.
To investigate the ability of insulin-like growth factor (IGF)-1 to prevent apoptosis in lens epithelial cells and the involvement of phosphatidylinositol 3-kinase (PI-3K)/Akt and PI-3K/p70 S6 kinase (p70 S6K) signaling in the cell-survival process. ⋯ These studies demonstrated a role for IGF-1 in the prevention of the lens epithelial cell apoptosis process. Furthermore, these studies indicated that anti-apoptotic and proliferative signals from IGF-1 bifurcate downstream of PI-3K. Whereas IGF-1-mediated PI-3K/Akt signaling plays a pivotal role in cell survival by inactivating proapoptotic Bad protein and suppressing caspase activation, its stimulation of the PI-3K/p70 S6K cascade promotes proliferation.
-
Invest. Ophthalmol. Vis. Sci. · Aug 2004
The Duncker illusion: intersubject variability, brief exposure, and the role of eye movements in its generation.
The Duncker illusion, also known as induced motion, is the illusory component of an object's motion that results from background movement. The origins of this robust phenomenon are still subject to debate. The goal of this study was to examine the role eye movements play in its generation. ⋯ The illusion is robust in that it is perceived under a wide variety of conditions by all observers. By varying the parameters, it was possible to demonstrate that eye movements do not play a role in generating the illusion and that this robust illusion is most likely caused by the visual system attributing relative motion between target and background to target motion and ignoring any true background movement. The mechanism by which this occurs varies in degree between individuals.