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Normal Retina (normal + retina)

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Life Sciences	75%

Selected Abstracts

Expression of glial fibrillary acidic protein and glutamine synthetase by Müller cells after optic nerve damage and intravitreal application of brain-derived neurotrophic factor

GLIA, Issue 2 2002
Hao 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]

The Presence of Megamitochondria in the Ellipsoid of Photoreceptor Inner Segment of the Zebrafish Retina

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 6 2005
J. Kim
Summary Although the megamitochondria (MM) were localized in various pathological conditions, normal retina of some mammalian species was reported to include MM for various physiological roles. However, it was not clearly confirmed whether the MM is present in the retina of lower vertebrate as well. In this study, we tried to show the presence of the MM in the zebrafish retina using electron microscopic technique. In all the photoreceptors including rods, cones and double cones of the zebrafish retina, MM were observed in the ellipsoid of inner segment. In the photoreceptor epllipsoid of the zebrafish retina, the mitochondria located in the central portion of the ellipsoid had a highly electron-dense matrix, which were accompanied by the mitochondria with electron-lucent matrix in the apical portion of the ellipsoid. The presence of MM was more clearly discernable in the rods, which were localized under the double cones. This finding is somewhat different from those observed in the previous studies because MM were localized in the inner segment of cones, but were not in those of rods in the case of mammalian retina. Although the exact physiological meaning for the presence of MM in some vertebrate species should be further studied, the present study could show that the MM in the ellipsoid of the retinal photoreceptors was not only restricted in some mammalian species. [source]

1334: Autofluorescence: new tool to follow dry eye AMD?

ACTA OPHTHALMOLOGICA, Issue 2010
MN MENKE
Purpose In the pathophysiolgy of dry (atrophic) age related macular degeneration (AMD) aging of the retinal pigment epithelium (RPE) plays a key role. Accumulation of lipofuscin granules in the RPE cells represents a common downstream pathogenetic pathway in AMD. Lipofuscin is derived from chemically modified residues of incompletely digested photoreceptor outer segment discs. Detection of lipofuscin in vivo is possible by using fundus autofluorescence (FAF) imaging. The clinical application and possible implications of autofluorescence imaging in dry AMD will be discussed. Methods When stimulated with light in the blue to green range, lipofuscin granules emit a characteristic yellow fluorescence. FAF imaging using a scanning laser ophthalmoscope allows visualization of the topographic distribution of lipofuscin over large retinal areas. Examples of FAF images will be presented to demonstrate various FAF patterns and to discuss the clinical significance of these findings. Results In areas of geographic atrophy FAF images show very low autofluorescence intensity. This is due to the loss of RPE cells including the lipofuscin granules. In the junctional zone between atrophic and normal retina, levels of increased autofluorescence intensity may occur due to excessive accumulation of lipofuscin in the RPE cells. Longitudinal observations further suggest that the extension of the total area with increased autofluorescence intensity surrounding atrophy at baseline has a strong positive correlation with atrophy progression rate over time. Conclusion FAF imaging is an important diagnostic tool to follow the progression of dry AMD and other degenerative macular diseases and should always be considered in cases were the status of the RPE is unknown. [source]

Comparative proteomic analysis of differentially expressed proteins in primary retinoblastoma tumors

PROTEOMICS - CLINICAL APPLICATIONS, Issue 4 2010
Kandalam Mallikarjuna
Abstract Purpose: To understand the disease mechanism and to identify the potential tumor markers that would help in therapeutics, comparative proteomic analysis of 29 retinoblastoma (RB) tumors was performed using 14 non-neoplastic retinas (age ranged from 45 to 89 years) as control tissues. Experimental design: 2-DE and MALDI-TOF-TOF MS/MS were used to identify differentially expressed proteins. Results: Twenty-seven distinct differentially expressed proteins were identified, including 16 upregulated 11 downregulated proteins. Significantly, higher mRNA levels of apolipoprotein A1 (p<0.001), transferrin (TF; p<0.001), CRABP2 (p<0.001), ,-crystallin A (CRYAA; p<0.001) were observed in RBs when compared with normal retinas and hence are consistent with the proteomic data. Immunohistochemistry was also performed for selected proteins on paraffin RB blocks to confirm protein expression. RB with invasion showed significantly higher expression by 2-DE-MS/MS analysis of CRABP2 (p<0.001), peroxiredoxin 6 (p=0.025), apolipoprotein A1 (p<0.001), recoverin (p<0.001). Conclusions and clinical relevance: Thus, this study provides a dynamic protein profile of RB tumors, which could provide clues to study the mechanisms of RB oncogenesis and possibly be developed as potential biomarkers for prognosis and therapy. [source]