摘要:

The efficiency of protein immobilization to provide a hydrogel surface with a high affinity for corneal epithelial cells was investigated. The cell adhesive proteins collagen and fibronectin, and the cell adhesive oligopeptide RGDS(arginine-glycine-aspartic acid-serine) were successfully covalently immobilized on poly(vinyl alcohol)(PVA) hydrogel sheets. Corneal epithelial cells and L-929 cells were applied to these surfaces. A large number of cells did adhere and proliferate on these protein-bound surfaces in comparison with the virgin PVA not so immobilized.

ISSN:0271-3683    

DOI:10.3109/02713689109020325

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Using experimental model of uveitis, the inflammation-associated chemiluminescence was measured by luminol amplification method. The induction of uveitis in Lewis rats was carried out by immunizing bovine S-antigen in complete Freund's adjuvant on hind foot-pad. The chemiluminescence activity from six sets of retina and choroid measured at the peak of inflammation was found to be in the range of 300,000-400,000 counts, amounting to nearly 20- fold increase from non-immunizated control animals under the same conditions. The phagocyte-derived superoxide anion and hydroxyl radical appear to be the two major radicals in the chemiluminescent species. This was revealed by in vitro suppression of chemiluminescence by 5,400 units of superoxide dismutase and 10 mM of D-mannitol. The decreases in counts were 21% and 35% for superoxide dismutase and D-mannitol respectively. The presence of hydrogen peroxide was not established since catalase with dose up to 20,000 units did not cause any significant suppression in counts. In the time sequence studies covering the entire course of uveitis development, the level of chemiluminescent species at day 9 postimmunization increased to 1.5-fold that of day 0, continued to increase to a maximum of 18-fold on day 12 and decreased slowly to about 3-fold in day 19. The pattern of increase appears to coincide with our previous findings in the number of polymorphonuclear leukocytes, the extent of membrane lipid peroxidation and the degree of retinal degeneration. Thus, these radicals play an important role in initiation as well as perpetuation of the membrane oxidative processes that lead to retinal degeneration.

ISSN:0271-3683    

DOI:10.3109/02713689109020326

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Retinal pigment epithelial (RPE) and corneal endothelial (CE) cells, because of their locations and functions, are continuously exposed to toxic oxidants. Protection from these toxic materials may be due, in part, to the action of endogenous antioxidant enzymes. We have established the presence of mRNAs that encode antioxidant enzymes in bovine RPE and CE cells and have determined the effect of bacterial lipopolysaccharide (LPS) on their expression. The most striking change in antioxidant enzyme expression is an increase in the level of mitochondrial manganous superoxide dismutase (MnSOD) mRNA in the LPS-treated RPE and CE cells. This increase in mRNA expression is accompanied by a slight increase in MnSOD activity as determined by SOD activity gels.

ISSN:0271-3683    

DOI:10.3109/02713689109020327

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Although the presence and role of oxygen reactive species in uveal inflammation is the subject of intense investigation, there is little direct evidence that oxygen metabolites are present at the site of inflammation. We used the nitroblue tetrazolium test for superoxide to determine production of this oxygen reactive species in experimental autoimmune uveitis (EAU). The choroidal tissues of animals with this disease contained intracellular, blue-staining granules. Most of the positive staining cells appeared to be polymorphonuclear leukocytes. This localization of superoxide in EAU is further evidence of the generation of oxygen reactive species in uveal inflammation.

ISSN:0271-3683    

DOI:10.3109/02713689109020328

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Loteprednol etabonate (LE) is a“soft”steroid belonging to a unique class of glucocorticoids. LE possesses a metabolically labile 17β-chloromethyl ester function which was designed in order to be hydrolyzed to an inactive carboxylic acid moiety. The ocular absorption and metabolism of a14C-labelled LE was evaluated in New-Zealand White rabbits after administration of a 0.5% suspension in both eyes. At various time points following ocular administration, the cornea, aqueous humor, and iris-ciliary body were collected. LE and the putative inactive metabolites, PJ-90 and PJ-91, were identified in all 3 tissues. Levels of LE and its metabolites were highest in the cornea, and so was the ratio of metabolites to unchanged drug, suggesting that the primary site of deactivation of the drug is the corneal tissue. A substantial amount of metabolites were also detected in the iris-ciliary body, although to a lesser extent than in the cornea. The amount of drug and metabolites in the aqueous humor was very low. It is concluded that LE is indeed a soft steroid with good ocular permeation properties.

ISSN:0271-3683    

DOI:10.3109/02713689109020329

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

While good visual acuity and refractive results after epikeratoplasty for aphakia have been reported, particularly for adults and older children, limited detailed information on the nature of the resulting vision is available. We have evaluated the visual performance of seven aphakic subjects corrected by epikeratoplasty by measuring contrast sensitivity, with and without the presence of glare. These results were compared with those for other aphakic corrections, namely spectacles (n=5 eyes), contact lenses (n=5 eyes), or intraocular lens implantation (n=5 eyes). There were statistically significant differences among these four aphakic correction types (p=0.0330), with a consistent trend for diminished visual performance after epikeratoplasty. Threshold elevations occurred in the presence of glare, but they were not statistically different between the groups (p=0.1631). Based on these visual assessments, epikeratoplasty does result in statistically significant visual losses. Despite this, it may still offer an acceptable alternative to other managements of the aphakic patient when those others are contraindicated.

ISSN:0271-3683    

DOI:10.3109/02713689109020330

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The effects of macrophage transplants on photoreceptor cell survival in retinas of Royal College of Surgeons (RCS) dystrophic rats were contrasted with RPE-cell transplants, sham-injection and surgical controls. The effects of these different treatments on the thickness and total area of the outer nuclear layer (ONL) were evaluated by light and electron microscopy at 1, 2 and 5 months after transplantation or surgical manipulations. Macrophage transplants into dystrophic retinas, although significantly reducing the debris zone thickness (p<0.01), had little effect on photoreceptor cell survival (2-3 cells thick ONL) after two months. In contrast, two months after RPE-cell transplantation, retinas exhibited an 8-10 cell thick ONL. Also, inner and outer segments of rescued photoreceptor cells were present, especially in areas directly beneath RPE-cell transplants. At the same time period, retinas injected with saline had a 2-3 cell thick ONL with no organized inner or outer segments. Furthermore, the affected ONL area in macrophage-transplanted or saline-injected retinas was significantly smaller than that seen in RPE-cell transplanted retinas (p<0.0001). Surviving photoreceptor cells were found only in the RPE-cell transplanted retinas five months after treatment. No effect on photoreceptor cell survival was seen in saline-injected, needle-inserted or incision-only retinas. Thus, transplantation of healthy RPE cells is an effective long-term therapeutic approach to correct the genetic defect in retinas of RCS dystrophic rats.

ISSN:0271-3683    

DOI:10.3109/02713689109020331

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Known functions of the RPE include glucose, water and retinoid transports; an ion transport mechanism utilizing a Na+- K+-ATPase pump located in the apical membrane has been proposed. Recent studies with cultured RPE cells of cat and bovine indicate that the RPE takes up ascorbate by an active mechanism, in this study we use a mounted bullfrog RPE preparation to study unidirectional and net fluxes of radiolabeled (14C)-ascorbic acid (AA), (14C)-dehydroascorbic acid, (3H)-L- glucose(L-glu) and (14C)-3-O-methyl-D-glucose(mD-glu) in an effort to explore the mechanism whereby AA moves across this tissue.Comparative flux studies with AA indicated that the retina to blood side (apical to basal :AB) flux of AA was more than 6x that of L-glu, a passive marker of comparable size. The reverse BA flux of AA was not significantly different from that of L-glu. Flux studies of L-glu, mD-glu and dehydroascorbic acid revealed no“net”flux across the mounted RPE; significantly, only AA demonstrated a net flux from retina to choroid (AB). The AB flux of reduced ascorbate was significantly greater than that of dehydroascorbic acid indicating specificity of carrier mediation. Apical ouabain (10-−4M) and sodium replacement in the bathing medium reduced the AB and net flux of AA significantly suggesting the requirement of a functioning Na+-K+-ATPase on the apical side membrane of the RPE. Energy blocker, dinitrophenol decreased unidirectional AB and net AA fluxes. Phloridzin (10-−4) administered only via the apical side of the RPE decreased net AA flux whereas phloretin and cytochalasin B, facilitated glucose carrier blockers, had no effect.These results suggest the presence of a Na+/ascorbate co-transport carrier in the apical membrane of the RPE that uses the sodium gradient to move AA across the RPE from retina to blood side. It remains unclear whetherin vivothe RPE moves AA to establish a gradient from the anterior to posterior regions of the eye or for some other unknown metabolic purpose of its own.

ISSN:0271-3683    

DOI:10.3109/02713689109020332

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

Prostaglandins (PGs) of the E series have been shown to modulate sympathetic neurotransmitter release in a variety of peripheral tissues and organs, including the eye. In this study, we evaluated the inhibitory effects of a series of naturally-occurring and synthetic PGs on field stimulation-evoked release of H-norepinephrine (H-NE) from isolated, superfused segments of human iris-ciliary body. Field-stimulated H-NE secretion was calcium-dependent, blocked by selective inhibitors of voltage-sensitive calcium and sodium channels, and originated from a desipramine-sensitive transmitter pool. Evoked H-NE release was inhibited in a concentration-dependent manner by PGE2(EC50=45 nM) and several closely related compounds with the following rank order of potency: sulprostone>16,16-dimethyl-PGE2>PGE2>11-deoxy-PGE1. By contrast, PGF2αwas relatively inactive (EC50>10μ, UM) in this system. None of the above compounds significantly modified spontaneous H-NE efflux. PGE2-mediated inhibition was not antagonized by the selective prostanoid EP -receptor antagonists AH 6809 (10μM) or SC-19220 (30μM), nor did these agents alone affect basal or field-stimulated3H-NE release. The results suggest that human ocular sympathetic nerves possess inhibitory PG receptors which have the pharmacological properties of the EP3subtype. These receptors may play a role in local feedback regulation of sympathetic transmission in the iris-ciliary body, and may contribute to symptoms of acute ocular inflammation, including vasodilation, miosis and hypotony.

ISSN:0271-3683    

DOI:10.3109/02713689109020333

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

The rhodopsin content of 20 eyes of infants and children ages 27 weeks gestation to 8 years (11 donors) was assayed and compared to the rhodopsin content of adults (36 eyes; 19 donors). Infants have significantly lower rhodopsin contents than adults. On average the rhodopsin content of young infants is about a third of adults. Previously reported full-field b-wave sensitivity of young infants is about 0.5 log units, that is about a third, less than adults. Thus, as previously found in infant rats, photon capture by rhodopsin appears to limit the dark adapted sensitivity of young human infants.

ISSN:0271-3683    

DOI:10.3109/02713689109020334

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor