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Ganglion Cell Layer (ganglion + cell_layer)
Selected AbstractsZac1 promotes a Müller glial cell fate and interferes with retinal ganglion cell differentiation in Xenopus retinaDEVELOPMENTAL DYNAMICS, Issue 1 2007Lin Ma Abstract The timing of cell cycle exit is tightly linked to cell fate specification in the developing retina. Accordingly, several tumor suppressor genes, which are key regulators of cell cycle exit in cancer cells, play critical roles in retinogenesis. Here we investigated the role of Zac1, a tumor suppressor gene encoding a zinc finger transcription factor, in retinal development. Strikingly, in gain-of-function assays in Xenopus, mouse Zac1 promotes proliferation and apoptosis at an intermediate stage of retinogenesis. Zac1 also influences cell fate decisions, preferentially promoting the differentiation of tumor-like clusters of abnormal neuronal cells in the ganglion cell layer, as well as inducing the formation of supernumerary Müller glial cells at the expense of other cell types. Thus Zac1 has the capacity to influence cell cycle exit, and cell fate specification and differentiation decisions by retinal progenitors, suggesting that further functional studies will uncover new insights into how retinogenesis is regulated. Developmental Dynamics 236:192,202, 2007. © 2006 Wiley-Liss, Inc. [source] Changing patterns of ganglion cell coupling and connexin expression during chick retinal developmentDEVELOPMENTAL NEUROBIOLOGY, Issue 4 2002David L. Becker Abstract We have used dye injection and immunolabeling to investigate the relationship between connexin (Cx) expression and dye coupling between ganglion cells (GCs) and other cells of the embryonic chick retina between embryonic days 5 and 14 (E5,14). At E5, GCs were usually coupled, via soma-somatic or dendro-somatic contacts, to only one or two other cells. Coupling increased with time until E11 when GCs were often coupled to more than a dozen other cells with somata in the ganglion cell layer (GCL) or inner nuclear layer (INL). These coupled clusters occupied large areas of the retina and coupling was via dendro-dendritic contacts. By E14, after the onset of synaptogenesis and at a time of marked cell death, dye coupling was markedly decreased with GCs coupled to three or four partners. At this time, coupling was usually to cells of the same morphology, whereas earlier coupling was heterogeneous. Between E5 and E11, GCs were sometimes coupled to cells of neuroepithelial morphology that spanned the thickness of the retina. The expression of Cx 26, 32, and 43 differed and their distribution changed during the period studied, showing correlation with events such as proliferation, migration, and synaptogenesis. These results suggest specific roles for gap junctions and Cx's during retinal development. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 280,293, 2002 [source] Inactivation of astroglial NF-,B promotes survival of retinal neurons following ischemic injuryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2009Galina Dvoriantchikova Abstract Reactive astrocytes have been implicated in neuronal loss following ischemic stroke. However, the molecular mechanisms associated with this process are yet to be fully elucidated. In this work, we tested the hypothesis that astroglial NF-,B, a key regulator of inflammatory responses, is a contributor to neuronal death following ischemic injury. We compared neuronal survival in the ganglion cell layer (GCL) after retinal ischemia-reperfusion in wild-type (WT) and in GFAP-I,B,-dn transgenic mice, where the NF-,B classical pathway is suppressed specifically in astrocytes. The GFAP-I,B,-dn mice showed significantly increased survival of neurons in the GCL following ischemic injury as compared with WT littermates. Neuroprotection was associated with significantly reduced expression of pro-inflammatory genes, encoding Tnf-,, Ccl2 (Mcp1), Cxcl10 (IP10), Icam1, Vcam1, several subunits of NADPH oxidase and NO-synthase in the retinas of GFAP-I,B,-dn mice. These data suggest that certain NF-,B-regulated pro-inflammatory and redox-active pathways are central to glial neurotoxicity induced by ischemic injury. The inhibition of these pathways in astrocytes may represent a feasible neuroprotective strategy for retinal ischemia and stroke. [source] Characterization and synaptic connectivity of melanopsin-containing ganglion cells in the primate retinaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2007Patricia R. Jusuf Abstract Melanopsin is a photopigment expressed in retinal ganglion cells, which are intrinsically photosensitive and are also involved in retinal circuits arising from rod and cone photoreceptors. This circuitry, however, is poorly understood. Here, we studied the morphology, distribution and synaptic input to melanopsin-containing ganglion cells in a New World monkey, the common marmoset (Callithrix jacchus). The dendrites of melanopsin-containing cells in marmoset stratify either close to the inner nuclear layer (outer stratifying), or close to the ganglion cell layer (inner stratifying). The dendritic fields of outer-stratifying cells tile the retina, with little overlap. However, the dendritic fields of outer-stratifying cells largely overlap with the dendritic fields of inner-stratifying cells. Thus, inner-stratifying and outer-stratifying cells may form functionally independent populations. The synaptic input to melanopsin-containing cells was determined using synaptic markers (antibodies to C-terminal binding protein 2, CtBP2, for presumed bipolar synapses, and antibodies to gephyrin for presumed amacrine synapses). Both outer-stratifying and inner-stratifying cells show colocalized immunoreactive puncta across their entire dendritic tree for both markers. The density of CtBP2 puncta on inner dendrites was about 50% higher than that on outer dendrites. The density of gephyrin puncta was comparable for outer and inner dendrites but higher than the density of CtBP2 puncta. The inner-stratifying cells may receive their input from a type of diffuse bipolar cell (DB6). Our results are consistent with the idea that both outer and inner melanopsin cells receive bipolar and amacrine input across their dendritic tree. [source] Dark-rearing-induced reduction of GABA and GAD and prevention of the effect by BDNF in the mouse retinaEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2006Eun-Jin Lee Abstract Gamma-aminobutyric acid (GABA) is an important retinal neurotransmitter. We studied the expression of GABA, glutamate decarboxylase 65 (GAD65) and GAD67 by immunocytochemistry and Western blot, in the retinas of control and dark-reared C57BL/6J black mice. This study asked three questions. First, is visual input necessary for the normal expression of GABA, GAD65 and GAD67? Second, can the retina recover from the effects of dark-rearing if returned to a normal light,dark cycle? Third, does BDNF prevent the influence of dark-rearing on the expression of GABA and GAD? At postnatal day 10 (P10), before eye opening, GABA immunoreactivity was present in the ganglion cell layer (GCL), in the innermost rows of the inner nuclear layer (INL) and throughout the inner plexiform layer (IPL) of control and dark-reared retinas. In P30 control retinas, GABA immunoreactivity showed similar patterns to those at P10. However, in P30 dark-reared retinas, the density of GABA-immunoreactive cells was lower in both the INL and GCL than in control retinas. In addition, visual deprivation retarded GABA immunoreactivity in the IPL. Western blot analysis showed corresponding differences in the levels of GAD65 but not of GAD67 expression between control and dark-rearing conditions. In our study, dark-rearing effects were reversed when the mice were put in normal cyclic light,dark conditions for 2 weeks. Moreover, dark-reared retinas treated with BDNF showed normal expression of both GABA and GAD65. Our data indicate that normal expression of GABA and GAD65 is dependent on visual input. Furthermore, the data suggest that BDNF controls this dependence. [source] Expression of glial fibrillary acidic protein and glutamine synthetase by Müller cells after optic nerve damage and intravitreal application of brain-derived neurotrophic factorGLIA, Issue 2 2002Hao Chen Abstract Müller glia play an important role in maintaining retinal homeostasis, and brain-derived neurotrophic factor (BDNF) has proven to be an effective retinal ganglion cell (RGC) neuroprotectant following optic nerve injury. The goal of these studies was to investigate the relation between optic nerve injury and Müller cell activation, and to determine the extent to which BDNF affects the injury response of Müller cells. Using immunocytochemistry and Western blot analysis, temporal changes in the expression of glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) were examined in rats after optic nerve crush alone, or in conjunction with an intravitreal injection of BDNF (5 ,g). GFAP protein levels were normal at 1 day post-crush, but increased ,9-fold by day 3 and remained elevated over the 2-week period studied. Müller cell GS expression remained stable after optic nerve crush, but the protein showed a transient shift in its cellular distribution; during the initial 24-h period post-crush the GS protein appeared to translocate from the cell body to the inner and outer glial processes, and particularly to the basal endfeet located in the ganglion cell layer. BDNF alone, or in combination with optic nerve crush, did not have a significant effect on the expression of either GFAP or GS compared with the normal retina, or after optic nerve crush alone, respectively. The data indicate that although BDNF is a potent neuroprotectant in the vertebrate retina, it does not appear to have a significant influence on Müller cell expression of either GS or GFAP in response to optic nerve injury. GLIA 38:115,125, 2002. © 2002 Wiley-Liss, Inc. [source] Cell-penetrating peptide TAT-mediated delivery of acidic FGF to retina and protection against ischemia,reperfusion injury in ratsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 7 2010Yi Wang Abstract The development of non-invasive ocular drug delivery systems is of practical importance in the treatment of retinal disease. In this study, we evaluated the efficacy of transactivator of transcription protein transduction domain (TAT-PTD, TAT49,57) as a vehicle to deliver acidic FGF (aFGF) to retina in rats. TAT-conjugated aFGF-His (TAT-aFGF-His) exhibited efficient penetration into the retina following topical administration to the ocular surface. Immunochemical staining with anti-His revealed that TAT-aFGF-His proteins were readily found in the retina (mainly in the ganglion cell layer) at 30 min. and remained detectable for at least 8 hrs after administration. In contrast, His+ proteins were undetectable in the retina after topical administration of aFGF-His, indicating that aFGF-His cannot penetrate the ocular barrier. Furthermore, TAT-aFGF-His, but not aFGF-His, mediated significant protection against retinal ischemia,reperfusion (IR) injury. After IR injury, retina from TAT-aFGF-His-treated rats showed better-maintained inner retinal layer structure, reduced apoptosis of retinal ganglion cells and improved retinal function compared to those treated with aFGF-His or PBS. These results indicate that conjugation of TAT to aFGF-His can markedly improve the ability of aFGF-His to penetrate the ocular barrier without impairing its biological function. Thus, TAT49,57 provides a potential vehicle for efficient drug delivery in the treatment of retinal disease. [source] Age-related reduction in retinal deimination levels in the F344BN ratAGING CELL, Issue 3 2008Sanjoy K. Bhattacharya Summary Increased deimination and peptidyl arginine deiminase type 2 (PAD2) expression has been observed in age-related neurodegenerative diseases without discrimination between their aging and disease component. Here, we describe reduced levels of deimination commensurate with reduced protein, mRNA and activity of peptidylarginine deiminase type 2 in the retina, optic nerve and plasma of aged rats when compared to young rats. The decrease was significant in the ganglion cell layer, inner plexiform layer and inner nuclear layer. Because our observations suggest reduced deimination is a consequence of aging, we conclude that increased deimination must be a consequence of disease. Our findings are important to understand late-onset and progressive diseases such as glaucoma, pseudoexfoliation syndrome, age-related macular degeneration and Oguchi's disease. [source] Histopathological studies on viral nervous necrosis of sevenband grouper, Epinephelus septemfasciatus Thunberg, at the grow-out stageJOURNAL OF FISH DISEASES, Issue 7 2004S Tanaka Abstract Viral nervous necrosis caused by sevenband grouper nervous necrosis virus (SGNNV) has occurred in grow-out stages (0,3 years old) of sevenband grouper, Epinephelus septemfasciatus, since the 1980s. In the present study, based on histopathological features of the central nervous system (CNS) in naturally diseased fish, pernasal infection experiments using grow-out fish were performed and pernasal infection was established as a putative invasion route of SGNNV. The definite SGNNV-targeted cells were determined by histopathological studies including indirect fluorescent antibody test and electron microscopy. Nerve cells in the olfactory lobe were most extensively necrotized with vacuolation followed by infiltration of microglia and macrophages. Purkinje cells and Golgi cells were extensively infected in the cerebellum. Megalocells and small nerve cell nuclei were also infected in the preoptic area, thalamus, medulla oblongata and spinal cord. Only a few small nerve cells were infected in the olfactory bulb and optic tectum. The retina of some diseased fish displayed vacuolated bipolar cells of the inner nuclear layer and in the ganglion cell layer. These SGNNV-infected nerve cells displayed viroplasmic inclusions containing virions, vacuoles and myelin-like structures. Based on observed histopathological changes, the lesion of the CNS was characterized by encephalitis but not encephalopathy. [source] Glutamate receptors modulate sodium-dependent and calcium-independent vitamin C bidirectional transport in cultured avian retinal cellsJOURNAL OF NEUROCHEMISTRY, Issue 2 2009Camila Cabral Portugal Abstract Vitamin C is transported in the brain by sodium vitamin C co-transporter 2 (SVCT-2) for ascorbate and glucose transporters for dehydroascorbate. Here we have studied the expression of SVCT-2 and the uptake and release of [14C] ascorbate in chick retinal cells. SVCT-2 immunoreactivity was detected in rat and chick retina, specially in amacrine cells and in cells in the ganglion cell layer. Accordingly, SVCT-2 was expressed in cultured retinal neurons, but not in glial cells. [14C] ascorbate uptake was saturable and inhibited by sulfinpyrazone or sodium-free medium, but not by treatments that inhibit dehydroascorbate transport. Glutamate-stimulated vitamin C release was not inhibited by the glutamate transport inhibitor l -,-threo-benzylaspartate, indicating that vitamin C release was not mediated by glutamate uptake. Also, ascorbate had no effect on [3H] d -aspartate release, ruling out a glutamate/ascorbate exchange mechanism. 2-Carboxy-3-carboxymethyl-4-isopropenylpyrrolidine (Kainate) or NMDA stimulated the release, effects blocked by their respective antagonists 6,7-initroquinoxaline-2,3-dione (DNQX) or (5R,2S)-(1)-5-methyl-10,11-dihydro-5H -dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801). However, DNQX, but not MK-801 or 2-amino-5-phosphonopentanoic acid (APV), blocked the stimulation by glutamate. Interestingly, DNQX prevented the stimulation by NMDA, suggesting that the effect of NMDA was mediated by glutamate release and stimulation of non-NMDA receptors. The effect of glutamate was neither dependent on external calcium nor inhibited by 1,2-bis (2-aminophenoxy) ethane-N,,N,,N,,N,,-tetraacetic acid tetrakis (acetoxy-methyl ester) (BAPTA-AM), an internal calcium chelator, but was inhibited by sulfinpyrazone or by the absence of sodium. In conclusion, retinal cells take up and release vitamin C, probably through SVCT-2, and the release can be stimulated by NMDA or non-NMDA glutamate receptors. [source] Band 4.1 proteins are expressed in the retina and interact with both isoforms of the metabotropic glutamate receptor type 8JOURNAL OF NEUROCHEMISTRY, Issue 6 2008Melanie Rose Abstract The function of the CNS depends on the correct regulation of neurotransmitter receptors by interacting proteins. Here, we screened a retinal cDNA library for proteins interacting with the intracellular C-terminus of the metabotropic glutamate receptor isoform 8a (mGluR8a). The band 4.1B protein binds to the C-termini of mGluR8a and mGluR8b, co-localizes with these glutamate receptors in transfected mammalian cells, facilitates their cell surface expression and inhibits the mGluR8 mediated reduction of intracellular cAMP concentrations. In contrast, no interaction with 4.1B was observed for other mGluRs tested. Amino acids encoded by exons 19 and 20 of 4.1B and a stretch of four basic amino acids present in the mGluR8 C-termini mediate the protein interaction. Besides binding to 4.1B, mGluR8 isoforms interact with 4.1G, 4.1N, and 4.1R. Because band 4.1 transcripts undergo extensive alternative splicing, we analyzed the splicing pattern of interacting regions and detected a 4.1B isoform expressed specifically in the retina. Within this tissue, mGluR8 and 4.1B, 4.1G, 4.1N, and 4.1R show a comparable distribution, being expressed in both synaptic layers and in somata of the ganglion cell layer. In summary, our studies identified band 4.1 proteins as new players for the mGluR8 mediated signal transduction. [source] Differential distribution of voltage-gated potassium channels Kv 1.1,Kv1.6 in the rat retina during developmentJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2007M. Höltje Abstract The discharge behavior of neurons depends on a variable expression and sorting pattern of voltage-dependent potassium (Kv) channels that changes during development. The rodent retina represents a neuronal network whose main functions develop after birth. To obtain information about neuronal maturation we analyzed the expression of subunits of the Kv1 subfamily in the rat retina during postnatal development using immunocytochemistry and immunoelectron microscopy. At postnatal day 5 (P5) all the ,-subunits of Kv1.1,Kv1.6 channels were found to be expressed in the ganglion cell layer (GCL), most of them already at P1 or P3. Their expression upregulates postnatally and the pattern and distribution change in an isoform-specific manner. Additionally Kv1 channels are found in the outer and inner plexiform layer (OPL, IPL) and in the inner nuclear layer (INL) at different postnatal stages. In adult retina the Kv 1.3 channel localizes to the inner and outer segments of cones. In contrast, Kv1.4 is highly expressed in the outer retina at P8. In adult retina Kv1.4 occurs in rod inner segments (RIS) near the connecting cilium where it colocalizes with synapse associated protein SAP 97. By using confocal laser scanning microscopy we showed a differential localization of Kv1.1-1.6 to cholinergic amacrine and rod bipolar cells of the INL of the adult retina. © 2006 Wiley-Liss, Inc. [source] Alcohol-Induced Lipid and Morphological Changes in Chick Retinal DevelopmentALCOHOLISM, Issue 5 2004Yolanda Aguilera Abstract: Background: Alcohol exposure causes alterations in the lipid content of different organs and a reduction of long-chain fatty acids. During embryo development, the central nervous system is extremely vulnerable to the teratogenic effects of alcohol, and the visual system is particularly sensitive. Methods: White Leghorn chick embryos were injected with 10- and 20-,l alcohol doses into the yolk sac at day 6 of incubation. The lipid composition of the retina was analyzed in embryos at day 7 of incubation (E7), E11, E15, and E18. The percentages of phospholipids, free cholesterol, esterified cholesterol, diacylglycerides, and free fatty acids were estimated by using an Iatroscan thin layer chromatography flame ionization detector. Gas chromatography and mass spectrometry were used to determine fatty acid composition. The morphological study was performed at E7, E11, and E19 by means of semithin and immunohistochemical techniques. Results: In the retina, alcohol causes the total lipid content to change, with a remarkable increase in free cholesterol and a dramatic decrease in esterified cholesterol. Diacylglycerides and free fatty acids tend to increase. Phosphatidylcholine and phosphatidylethanolamine decrease, whereas phosphatidylserine, sphingomyelin, and phosphatidylinositol increase. The main fatty acids of the retina also undergo changes. At E7, myriotic acid increases, and oleic acid and polyunsaturated fatty acids such as arachidonic acid and docosahexaenoic acid decrease. From E18 onward, there is some recovery, except for fatty acids, which recover earlier. From a morphological point of view, alcohol effects on retinal development are various: increase of intercellular spaces in all cell layers, pyknosis with loss of cellularity in the inner nuclear cell layer and ganglion cell layer, retarded or disorderly cell migration, early cell differentiation, and loss of immunoreactivity for myelin oligodendrocyte,specific protein. Conclusions: Acute alcohol exposure during embryo development causes the lipid composition of the retina to change, with a trend to recovery in the last stages. These alterations are in line with the changes observed at a morphological level. [source] Spatial patterning of cholinergic amacrine cells in the mouse retinaTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 2 2008Irene E. Whitney Mosaic of cholinergic amacrine cells (green, labeled for choline acetyltransferase) in the ganglion cell layer of the mouse retina. The somal patterning of the mosaic is degraded due to the presence of blood vessels (white, labeled for PNA) and fascicles of optic axon (magenta, labeled for neurofilaments). Also shown are the retinal astrocytes (blue, labeled for glial fibrillary acidic protein). J. Comp. Neurol. 508:1-12, 2008. © 2008 Wiley-Liss, Inc. [source] Spatial patterning of cholinergic amacrine cells in the mouse retinaTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2008Irene E. Whitney Mosaic of cholinergic amacrine cells (green, labeled for choline acetyltransferase) in the ganglion cell layer of the mouse retina. The somal patterning of the mosaic is degraded due to the presence of blood vessels (white, labeled for PNA) and fascicles of optic axon (magenta, labeled for neurofilaments). Also shown are the retinal astrocytes (blue, labeled for glial fibrillary acidic protein). J. Comp. Neurol. 508:1-12, 2008. © 2008 Wiley-Liss, Inc. [source] Spatial patterning of cholinergic amacrine cells in the mouse retinaTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 1 2008Irene E. Whitney Abstract The two populations of cholinergic amacrine cells in the inner nuclear layer (INL) and the ganglion cell layer (GCL) differ in their spatial organization in the mouse retina, but the basis for this difference is not understood. The present investigation examined this issue in six strains of mice that differ in their number of cholinergic cells, addressing how the regularity, packing, and spacing of these cells varies as a function of strain, layer, and density. The number of cholinergic cells was lower in the GCL than in the INL in all six strains. The nearest neighbor and Voronoi domain regularity indexes as well as the packing factor were each consistently lower for the GCL. While these regularity indexes and the packing factor were largely stable across variation in density, the effective radius was inversely related to density for both the GCL and INL, being smaller and more variable in the GCL. Consequently, despite the lower densities in the GCL, neighboring cells were more likely to be positioned closer to one another than in the higher-density INL, thereby reducing regularity and packing. This difference in the spatial organization of cholinergic cells may be due to the cells in the GCL having been passively displaced by fascicles of optic axons and an expanding retinal vasculature during development. In support of this interpretation, we show such displacement of cholinergic somata relative to their dendritic stalks and a decline in packing efficiency and regularity during postnatal development that is more severe for the GCL. J. Comp. Neurol. 508:1,12, 2008. © 2008 Wiley-Liss, Inc. [source] Clinical and histological findings after intravitreal injection of bevacizumab (Avastin®) in a porcine model of choroidal neovascularizationACTA OPHTHALMOLOGICA, Issue 3 2010Nathan Lassota Abstract. Purpose:, To examine the effect of intravitreally injected bevacizumab (Avastin®) on the histological and angiographic morphology of choroidal neovascularization (CNV) in a masked and placebo-controlled animal study. Methods:, Choroidal neovascularization was induced surgically in 11 porcine eyes by perforating Bruch's membrane with a retinal perforator. After closure of the ports used for the vitrectomy, which was performed to facilitate the Bruch's membrane rupture, 0.05 ml of either bevacizumab or Ringer-Lactat (placebo) was injected into the vitreous cavity. Eyes were enucleated after 14 days. Fundus photographs and fluorescein angiograms (FAs) were obtained immediately prior to enucleation. Sections of formalin- and paraffin-embedded eyes were examined by light microscopy and by immunohistochemical staining. Results:, Placebo-injected eyes exhibited the highest propensity to leak, with five of six eyes leaking on FA, whereas only one of five bevacizumab-injected eyes exhibited leakage. On histological examination, all 11 eyes contained CNV membranes of similar size, regardless of treatment. The number of vascular endothelial cells was significantly reduced (p = 0.03) in CNV membranes from eyes that had been injected with bevacizumab when compared with CNV membranes from placebo-injected eyes. There was a trend towards more retinal pigment epithelium cells (p = 0.16) and fewer glial fibres (p = 0.08) in membranes from bevacizumab-treated eyes compared with placebo-treated eyes. Bevacizumab was identified immunohistochemically in the inner limiting membrane (ILM) and to a lesser degree in the remaining retina. Strong staining was also detected in both retinal blood vessels and entire CNV membranes with no cellular predisposition. Vascular endothelial growth factor expression was found in the CNV membranes, in the ILM, in the ganglion cell layer, in Müller cells throughout the neuroretina and in retinal blood vessels. Conclusions:, Bevacizumab significantly reduced the proliferation of vascular endothelial cells in CNV membranes and showed a strong trend towards a reduction of leakage from these membranes. After a single injection, bevacizumab did not exhibit a size reducing effect on CNV, but it was still present in the membranes 14 days after intravitreal injection. [source] Electrophysiological evaluation and visual outcome in patients with central retinal vein occlusion, primary open-angle glaucoma and neovascular glaucomaACTA OPHTHALMOLOGICA, Issue 1 2010Elisabeth Wittström Abstract. Purpose:, To evaluate patients with central retinal vein occlusion (CRVO) and neovascular glaucoma (NVG) using electrophysiology in order to gain better understanding of visual outcome and risk factors, such as previously diagnosed primary open-angle glaucoma (POAG). Methods:, Eighty-three patients (83 eyes) initially presenting with CRVO and examined with full-field electroretinography (ERG) within 3 months of the thrombotic event were analysed retrospectively regarding treatment, risk factors and visual outcome. In addition, 30 patients initially presenting with NVG caused by CRVO were also investigated regarding risk factors using electrophysiology in order to determine the cause of their visual impairment. Results:, Nineteen (23%) of the 83 patients initially presenting with CRVO had been diagnosed previously with POAG. Ninety-five per cent (18/19) of all the patients with previously diagnosed glaucoma developed ischaemic CRVO. Thirty-four per cent of the patients initially presenting with CRVO (28/83) developed NVG. Sixty-eight per cent (13/19) of the patients with previous glaucoma developed NVG, compared to 23% (15/64) of the patients without previous POAG. In the patients who initially presented with NVG, full-field ERG demonstrated a remaining retinal function of both cones and rods, indicating that the main cause of visual impairment is ischaemia of the ganglion cell layer. Conclusion:, Glaucoma is a significant risk factor for developing ischaemic CRVO and subsequent NVG. The presence of POAG in CRVO worsens visual outcome. NVG is associated with preserved photoreceptor function, thus indicating ischaemia of the ganglion cell layer as the primary cause of visual impairment. This emphasizes the importance of prompt treatment of ischaemia and elevated intraocular pressure in these patients. [source] The distribution of neuroglobin in mouse eyeACTA OPHTHALMOLOGICA, Issue 2009Y YOU Purpose To determine the distribution of neuroglobin (Ngb) in mouse eye. Ngb is predominantly expressed in the nervous system,and at particularly high levels in the retina. Ngb may serve as a reactive oxygen scavenger and may protect the tissue of eye from ischemia/hypoxia injuries. However,the distribution of Ngb in the eye is still controversial. Methods Two polyclonal antibodies against Ngb were used in this immunohistochemical study, both of which were raised in rabbits. One of these two antibodies was generated against the whole recombinant protein of mouse Ngb and the other was generated against amino acid positions 55-70 of mouse and human Ngb. The expression of Ngb was analyzed with light microscopy on tissue sections. Results These two antibodies showed comparable results. Ngb was expressed in the layers of the retina, including the ganglion cell layer, inner and outer nuclear layers, inner and outer plexiform layers, the inner segments of the photoreceptors and the retinal pigment epithelium. Ngb was also detected in other structures of the eye, including the epithelium and endothelium of cornea,the stroma of iris,the ciliary body, the lens epithelium, and the sclera. However, Ngb was not expressed in the corneal stroma, the lens capsule, the lamellar fibers of lens, the pigment epithelium of ciliary body or the pigment layer of iris. Conclusion Ngb was found widely distributed in mouse eye. This finding can be explained by the fact that most of the structures of the eye originated from neural crest/neural ectoderm. Future experiments will focus on the distribution of Ngb at the mRNA level (in situ hybridization),and the quantitative expression levels at baseline and after hypoxic/ischemic challenge. [source] New blood for hemoglobin in the lens: roles in stem cell differentiation and fibre cell organelle loss?ACTA OPHTHALMOLOGICA, Issue 2008MA WRIDE Purpose Evidence is emerging for haemoglobin (Hb) expression outside the vascular system. We previously demonstrated Hb expression in the mouse lens during post-natal development and cataract progression. Here, we extended this work by carrying out a comprehensive spatio-temporal analysis of Hb subunit expression during mouse lens development and maturation. Methods We used RT-PCR, Western blotting and immunofluorescence to analyze Hb expression in mouse eyes (E16.5 to 9 wks). We also used a sensitive heme assay to test for the presence of heme in the lens by colourimetric assay and histological staining of paraffin-embedded sections. Results Hb subunits were expressed in lens epithelial cells and cortical lens fibre cells. However, the heme assay revealed negligible levels of this prosthetic group in the lens. Hb immunofluorescence was also observed in other regions of the developing eye including the cornea, the retinal ganglion cell layer and the retinal pigment epithelium. Finally, we also observed Hb expression in early embryos by microarray and during differentiation of embryonic stem (ES) cells into embryoid bodies (EBs) in vitro. Conclusion These results suggest a paradigm shift: Hb subunits are expressed in the eye during development and in the adult and, therefore, may have novel roles in ocular development, physiology and pathophysiology. The absence of heme from the lens indicates that at least some of these functions may be independent of oxygen metabolism. The pattern of expression of Hb in lens epithelial cells and cortical lens fibre cells may indicate an involvement for Hb subunits in lens epithelial cell differentiation into lens fibre cells and/or lens fibre cell organelle loss. [source] Quantification and characterization of GABA-ergic amacrine cells in the retina of GAD67-GFP knock-in miceACTA OPHTHALMOLOGICA, Issue 4 2008Christian Albrecht May Abstract. Purpose:, Although the presence of ,-aminobutyrate acid (GABA) in amacrine cells and its co-localization with other neuronal substances is well known, there exists only little information about their quantitative distribution in the mouse eye. The aim of the present study was to characterize GABA-ergic amacrine cells in the retina of the recently introduced glutamate decarboxylase 67-green fluorescent protein (GAD67-GFP) knock-in mouse. Methods:, Whole mounts of the retina were prepared and the GFP-positive neurons quantified. Immunofluorescence staining was performed with antibodies against GABA, calbindin (CB), calretinin (CR), parvalbumin (PV), choline acetyl transferase (ChAT), tyrosine hydroxylase (TH), vesicular glutamate transporter (VGluT) 1, VGluT2 and VGluT3. Results:, Displaced GABA-ergic amacrine cells in the ganglion cell layer (GCL) showed a density of 1006 ± 170 cells/mm2. In the inner nuclear layer (INL), the density of amacrine cells was 8821 ± 448 cells/mm2 in the central region and 6825 ± 408 cells/mm2 in the peripheral region. GFP-positive amacrine cells co-localized with GABA (99%), CR (INL 18%, GCL 71.3%), CB (INL 6.3%), bNOS (INL 1%, GCL 4%), and ChAT (INL 17%, GCL 92.6%). No co-localization was seen with antibodies against PV, TH, and VGluT 1-3. Conclusions:, This study presents the first quantitative data concerning the co-localization of GABA-ergic neurons in the mouse retina with various neuronal markers. [source] Pregnenolone Sulfate, a Naturally Occurring Excitotoxin Involved in Delayed Retinal Cell DeathJOURNAL OF NEUROCHEMISTRY, Issue 6 2000C. Cascio Abstract: 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 TUNEL-positive cells in the inner nuclear and ganglion cell layers. Necrotic signs were characterized by DNA smear migration, lactate dehydrogenase (LDH) release, and damage mainly in the inner nuclear layer. PS-induced delayed cell death was markedly reduced by the NMDA receptor antagonists 4-(3-phosphonopropyl)-2-piperazinecarboxylic acid and 3,-hydroxy-5,-pregnan-20-one sulfate but completely blocked after concomitant addition of the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione. Steroids with antioxidant properties (progesterone, dehydroepiandrosterone and its sulfate ester, and 17,-estradiol) differently prevented PS-induced delayed cell death. Cycloheximide treatment protected against DNA fragmentation and LDH release but failed to prevent the rise in SOD activity and TBARS level. We conclude that a brief PS pulse causes delayed cell death in a slowly evolving apoptotic fashion characterized by a cycloheximide-sensitive death program downstream of reactive oxygen species generation and lipid peroxidation, turning into secondary necrosis in a retinal cell subset. [source] | |||||||||||||