摘要:

In order to clarify the involvement of oxidative stress inin vitrosugar-induced cataractogenesis, we examined changes in lipid peroxide, reduced glutathione, vitamin E, and water contents following cataractogenesis in rat lenses cultured with 20 mM D-xylose over a period of 24 h. In D-xylose-treated lenses, an apparent opacity appeared at the equator after 6 h of D-xylose treatment, increases in lipid peroxide and water contents and decreases in reduced glutathione and vitamin E contents occurred with the appearance of opacity. We further examined the effect of the treatment of vitamin E in a liposomal form on cataractogenesis and the changes of lipid peroxide, reduced glutathione, vitamin E, water, and xylitol contents in rat lenses cultured with 20 mM D-xylose for 24 h. This vitamin E treatment significantly prevented not only cataractogenesis, but also an increase in lipid peroxide content and a decrease in vitamin E content in the D-xylose-treated lenses. However, the vitamin E treatment had no effect not only on a decrease in reduced glutathione content, but also on increases in water and xylitol contents, which are known to be induced via aldose reductase, in the D-xylose-treated lenses. These results indicate that not only osmotic stress but also oxidative stress should be involved in cataractogenesis in rat lenses cultured with D-xylose and support the involvement of oxidative stress inin vitrosugar-induced cataractogenesis.

ISSN:0271-3683    

DOI:10.3109/02713689609017605

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The goal of this study was to determine if an arrestin/S-antigenlike protein is produced by human retinal pigment epithelial (HRPE) cells maintained in tissue culture. Arrestin immunoreactivity was examined in fixed, monolayer cultures of HRPE and on immunoblots of SDS-PAGE separations of whole cell lysates of HRPE using five monoclonal antibodies (mAbs A2G5, A9C6, 3C4.2, 3D1.2 and 5c6.47) that bind to different epitopes in bovine retinal S-antigen. Monolayers of HRPE cells showed immunoreactivity with four of the mAbs though the relative staining intensity varied among mAbs and donors. For example, mAb A2G5 which historically shows very limited crossreactivity among species, reacted strongly with cells from one donor, moderately with cells from a second donor and only weakly with other donor cultures examined. mAb 3D1.2 showed no reactivity with HRPE cells. Immunoblots of SDS-PAGE separations of whole cell lysates of HRPE established from ten different donors confirmed the presence of an arrestin-related polypeptide that comigrated with retinal arrestin. These results demonstrate the presence of an arrestin-like protein in HRPE cells which have been maintained in tissue culture. Though the function of this arrestin homologue in HRPE is not yet established, it could play a role in the downregulation of receptor and/or transport protein activity.

ISSN:0271-3683    

DOI:10.3109/02713689609017606

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The goal of this study was to determine the effect of extracellular matrix components on the phagocytic function of the retinal pigment epithelial (RPE) cell. Cultured human fetal RPE cells were established in culture and plated on three commercially-prepared substrates: collagen IV, fibronectin and laminin and on three native matrices: bovine corneal endothelial cell matrix (BCEM) denuded bovine Bruch's membrane and denuded human Bruch's membrane. Cultured cells were allowed to become confluent and maintained for an additional two weeks before uptake of fluorescent bovine retinal outer segments (ROS) was measured by flow cytometry. Morphology by phase contrast microscopy and melanization was also determined as measures of differentiation. The results showed that morphology, melanization and ROS uptake by cells on collagen IV, laminin and fibronectin were not different from control cells plated on tissue culture plastic. However, ROS uptake by cells plated on BCEM was significantly less than that of cells cultured on plastic and melanization was greater. ROS uptake by cells plated on both types of Bruch's membrane was also significantly less than control cells. Treatment of cells plated on tissue culture plastic with 44 mM NaHCO3, which increased melanization, also reduced ROS uptake. We conclude that native matrices seem to contain components that significantly depress ROS uptake in culture. The inhibition is not mimicked by collagen, laminin or fibronectin coated wells. The ECM may play a significant role in controlling phagocytosis of ROS either by determining morphology, increasing differentiation or by directly influencing intracellular metabolism, and thus serve as another level of control for this RPE function which may not occur in cells plated on tissue culture plastic. These results may also have implications for the effects of aging or disease in which there are changes in the ECM.

ISSN:0271-3683    

DOI:10.3109/02713689609017607

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

This study was performed to develop and improve a completely definedin vitroocular wound-healing model of fibroblast proliferation for glaucoma filtration surgery. This model is essential for the investigation of protein-sensitive drugs and cytokines. Tenon's capsule fibroblasts in their third passage were incubated overnight, washed free of serum, and fed defined media, Aim V or Clonetics FBM serum-free medium containing platelet-derived growth factor, basic fibroblast growth factor, epidermal growth factor, or fibronectin at various dilutions and in combinations at optimum concentrations. Proliferation was measured by3H-thymidine incorporation at 1, 3, and 7 days. Morphology was compared to controls fed Minimum Essential Medium + 10% serum. Single factors stimulated the greatest amount of thymidine uptake on day 3. Optimum concentrations were epidermal growth factor at 5 ng/ml, basic fibroblast growth factor at 10 ng/ml and platelet-derived growth factor at 20 ng/ml. Identical combinations of factors stimulated nearly twice the thymidine uptake in Clonetics medium as in Aim V. Epidermal growth factor activity was inhibited by either basic fibroblast growth factor or platelet-derived growth factor. Basic fibroblast growth factor and platelet-derived growth factor together produced a less than additive effect. The performance of either serum-free medium may be improved by the addition of basic fibroblast growth factor or platelet-derived growth factor. The optimum serum-free medium (Clonetics FBM) with growth factors was unable to stimulate proliferation as much as Minimum Essential Medium + 10% NBS, but was successful in maintaining viability during the 7 day test period.

ISSN:0271-3683    

DOI:10.3109/02713689609017608

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The ultrastructure of hyaluronic acid (HA) and collagen in the human vitreous was investigated. After fixation with 4% glutaraldehyde and 0.1% cetylpyridinium chloride (CPC), sectioned blocks of retina and attached vitreous body were stained with 500 ppm ruthenium red (RR) in 1.25% glutaraldehyde, postfixed with 500 ppm RR in 2% OsO4, and embedded in Epon 812. In addition, collagen II immunostaining was done. Collagen fibrils were coated with amorphous material believed to be HA. No amorphous material was seen in the fibrils in the cortical areas adjacent to the retina, but the amount of material gradually increased toward the center of the vitreous body. By using anti-collagen II antibody, we showed the presence of collagen II, often oriented perpendicular to the surface. The central vitreous demonstrated some dense materials that were collagen fibrils packed into bundles of parallel fibrils.In summary, collagen fibrils contained little HA in the cortical areas adjacent to the retina, but they were packed into bundles of parallel fibrils in the central vitreous.

ISSN:0271-3683    

DOI:10.3109/02713689609017609

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Descemet's membrane, the specialised basement membrane of the corneal endothelium, contains a form of extracellular matrix described as wide-spaced collagen. In healthy human Descemet's membrane, wide-spaced collagen forms a highly ordered array in a region called the anterior banded zone. However, in corneal endotheliopathies such as Fuchs' endothelial dystrophy and the iridocorneal-endothelial syndrome large amounts of wide-spaced collagen are deposited posterior to Descemet's membrane in a grotesque parody of the anterior banded zone termed a posterior collagenous layer. The purpose of this study was to identify the composition of the wide-spaced collagen found in the Descemet's membrane of normal and diseased human corneas.Tissue from three normal human corneas, three from patients with Fuchs' endothelial dystrophy and five from patients with the iridocorneal-endothelial syndrome was prepared for immunoelectron microscopy by freezing or embedding in Lowicryl K4M resin. Immunocytochemistry on ultrathin sections was performed with antibodies to collagen Types I, III, V, VI and VIII, fibronectin. laminin, P component and tenascin.Ultrastructural labelling of the wide-spaced collagen in the anterior banded zone of normal and diseased corneas and also of the wide-spaced collagen in the posterior collagenous layer of all the diseased corneas was demonstrated with antibody to collagen Type VIII. Wide-spaced collagen was not labelled by any of the other antibodies used.Large amounts of Type VIII collagen are present in discrete regions of healthy and diseased Descemet's membrane. The deposition of Type VIII collagen may significantly influence the pathobiology of the corneal endotheliopathies.

ISSN:0271-3683    

DOI:10.3109/02713689609017610

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The National Eye Institute (NEI) computer planimetry system has been shown to have good reproducibility in assessing the size of cortical cataracts from retroilluminatin photographs. In this study, we determined the usefulness of this system in monitoring cortical cataract changes over time. Using the Neitz Kawara retroillumination camera, retroillumination photographs of cortical cataracts in 81 eyes were obtained every six months for an average of 31 months. As previously described, the cortical cataract outlines were traced in a masked fashion onto trans-parent plastic overlays, and the tracings then digitized into a Macintosh Quadra computer using a computer scanner. Cortical cataract area was then determined using a specially developed software program. For each eye, the rate of cortical area change was determined by the slope of the regression line fitted to the follow-up measurements. Cataract progression was classified to be significant if the slope exceeded a critical value. Of the 81 eyes, 24 (30%) had significant cataract progression, while 57 (70%) did not progress. This study presents data on progression of the area of cortical cataracts and suggests the usefulness of the NEI computer planimetry system for monitoring such changes from retroillumination photographs. The slope-based test can also play a useful part in longitudinal studies with irregular time intervals and variable number of visits.

ISSN:0271-3683    

DOI:10.3109/02713689609017611

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

We examined the pathogenesis of reduced amplitude in electroretinogram (ERG) oscillatory potentials (OPs) in diabetes, in relation to possible changes in the metabolisms involving retinal amino acid neurotransmitters. With use of streptozotocin diabetic rats, flash ERGs were recorded and quantitative analyses of retinal free amino acids were performed. Immunocytochemical localizations of retinal glycine and GABA were examined. In addition, activities of glutamic acid decarboxylase (GAD) and GABA transaminase (GABA-T) were measured. Our results revealed that the amplitudes of OP 1 and OP 2 decreased, and retinal glycine and GABA content significantly increased in the diabetic rats. An increased immunoreactivity of GABA was observed in Muller cells in the diabetic rat retinas, while no apparent changes were found in glycine immunoreactivity. Finally, increased activations of GAD with reduced activities of GABA-T were observed in the diabetic rat retinas. Thus, reduced amplitudes of OPs were associated with changes in content, localization, and enzyme activities related to GABA in the retinas, implying that changes in GABA metabolism can be a candidate for the pathogenesis of the abnormal OPs in diabetes.

ISSN:0271-3683    

DOI:10.3109/02713689609017612

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Pharmacological profiles of endothelin (ET) receptors in the isolated rabbit iris sphincter were characterized. ET isopeptides caused dose-dependent contraction of the preparation. The respective EC50values for ET-1, ET-2 and ET-3 were 39.4, 58.0 and 84.3 nM, so that ET-1 was twice as potent as ET-3. Sarafotoxin (SRTX) -b, an ETA/ETBnon-selective agonist, caused very potent contraction with an EC50of 1.13 nM. However, selective ETBreceptor agonists SRTX-cand IRL 1620 showed no contractile activity up to 1μM.BQ-123, a selective ETAreceptor antagonist, shifted the dose-response curves of ET isopeptides to the right. The pA2value for ET-I was 5.52 with a slope of 1.06, which is not different from unity, and the pKBvalue for ET-2 was 5.06. Interestingly, very low doses of BQ-123 antagonized responses to ET-3 and SRTX-b, with a Schild plot slope of approximately 0.7 which is significantly different from unity, suggesting receptor heterogeneity. The abscissal intercepts of the Schild plots were–9.29 for ET-3 and–8.53 for SRTX-b. FR 139317, another ETAreceptor antagonist, also preferentially antagonized responses to ET-3. RES 701-1, a selective ETBreceptor antagonist, did not shift dose-response curves for ET-1 and ET-3.These results suggest that ET receptors in the rabbit iris sphincter muscle cannot be classified into the ETA, ETBor ETcreceptor subtypes, so far established. When compared to the established receptor subtypes, ET receptors in this preparation were quite different from the ETBreceptor, but apparently showed a pharmacological profile most similar to the ETAreceptor, suggesting the presence of heterogeneous and atypical ETAreceptors.

ISSN:0271-3683    

DOI:10.3109/02713689609017613

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Chick eyes occluded for various periods or treated with various concentrations of kainic acid (KA) or 2-amino-4-phosphonobutylate (APB) during development showed characteristic changes of electroretinography and of refraction. In occluded eyes, oscillatory potential amplitudes (OP-A) were reduced, even with high-intensity stimulation, in proportion to duration of occlusion, but b wave amplitude was unchanged, implying functional changes in inner layers of the deprived retina. OP-A reduction after only 1 week of occlusion and reversibility of this change might reflect retinal changes preceding axial elongation. KA was confirmed to induce myopia with axial elongation and APB to induce hyperopia with axial shortening. KA and APB both suppressed OP-A. KA reduced ON and OFF responses, but low-dose APB suppressed only ON responses. Study results suggest that myopia could be induced by changes of inner retina mediating OP attenuation and degradation of ON and OFF responses.This manuscript reports unpublished work that is not currently under consideration for publication elsewhere.

ISSN:0271-3683    

DOI:10.3109/02713689609017614

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor