ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

This paper reports the results of 99 penetrating kerato-plasties for aphakic and pseudophakic corneal edema using a single-piece, semielastic anterior chamber lens. There were 24 patients with aphakic corneal edema and 75 with pseudophakic corneal edema. Most cases had history compatible with macular disease. A Cilco-Kelman multiflex anterior chamber lens was used in all cases. All intraocular lenses were removed from pseudophakic eyes (38 iris supported lenses and 37 anterior chamber lenses). Preoperative glaucoma was present in over 20% of all cases. Grafted eyes were followed from 1 to 5 years. There were 24 clear grafts in aphakic eyes (87%) and 72 in pseudophakic eyes (96%). Visual improvement occurred in 30% of aphakic eyes and in 10% of pseudophakic eyes. In 50% of both groups, vision improved to better than 20/100. The study shows that the use of this type of anterior chamber lens did not affect the outcome of corneal grafts, and that there were no differences in graft results between the two groups. Visual acuity results were related to retinal changes.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Topical citrate has been shown to significantly reduce the severity and incidence of corneal ulceration in alkali-burned rabbit eyes. Subcutaneous injection of citrate significantly reduced the severity of ulceration. This study was performed to determine the plasma citrate and ionized calcium levels after systemic administration of citrate. Repeated ingestion of citric acid capsules showed a small increase in the plasma citrate level, but no significant change in the level of ionized serum calcium 30 min after the last ingestion. A single dose of Polycitra-LC (6.672 g of citrate) more than doubled the baseline citrate concentration but only induced a 5% decrease in the level of ionized serum calcium 30 min after ingestion. Neither regimen of orally administered citrate produced any significant effect on the respiratory burst or adherence of in vitro pplymorphonuclear leukocytes (PMNs) resus-pended in their respective plasma. In comparison studies, higher levels of plasma citrate and lower levels of ionized serum calcium were achieved through plateletpheresis. The respiratory burst and adherence of PMNs were not statistically different from baseline PMNs. However, there was an inverse correlation between the miromolat-increase in citrate or the micromolar decrease in calcium and the respiratory burst. These results suggest that the use of oral citrate alone may not be practical, but does not peclude the use of oral citrate as a supplement to topical citrate.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Seven human corneas were studied, using the enzyme-linked immunosorbent assay (ELISA) technique, for expression of human leukocyte antigens (HLA) class-l and class-11 antigens on the epithelial cells of the central 8-mm corneal button and the remaining corneal periphery and limbus. The antigenicity was compared with that of Raji and Daudi cell lines, which served as controls. It was demonstrated that the epithelium of the two corneal parts shows a high expression of HLA class-I antigens, albeit not as strong as that found in the control cell lines. On the other hand. HLA class-11 antigens were found only in the limbal-peripheral area. Expression of the HLA class-1 antigens was weaker in the central portion of the cornea. It is proposed that the absence of HLA class-11 antigens expression in the central portion of the cornea offers an additional explanation for the greater success of small corneal grafts, since the recognition step necessary for the immunological response is lacking.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Twelve F1TC-conjugated lectins were used to establish a reaction pattern with cellular and noncellular components in fresh-frozen and formalin-fixed paraffin sections of II normal human corneas. In frozen sections the epithelium demonstrated the most active lectin staining: keratocytes and endothelium stained to a lesser degree. Of the noncellular components, the epithelial basement membrane and Descemet's membrane of some of the tissues were stained most byPhasolus vulgarisagglutinin (PHA),Pisum sativionagglutinin (PSA). Concanavalin A (Con-A). andSopora japonicaagglutinin (SJA). None of the lectins stained Bowman's layer or the stromal matrix. Keratocytes in paraffin sections stained the most compared with the epithelium and endothelium. In paraffin sections, the epithelial basement membrane and Bowman's layer of some of the tissue sections were stained by Con-A.Ricinus cummuniagglutinin 120 (RCA-120),Banderiraea simplicifolialectin (BSL-1). PHA. and wheat germ agglutinin (WGA). From this study, it was observed that the reactivity of lectins to the cellular components in paraffin-embedded sections was less pronounced than in frozen sections. Sensitivity of lectin binding was considerably enhanced by the proteo-lytic enzyme digestion of paraffin sections.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Microtubules constitute one of the three components of the cellular skeleton (cytoskeleton) and have been implicated in the control of cell polarity, shape, intracellular transport, directional cell motility. and mitosis. With specific antibodies against tubulin, the principal microtu-bular protein, the cytoplasmic distribution of microtu-bules was demonstrated in tissue-cultured rat cornea) epithelium. This was compared with the distribution of actin, another component of the cytoskeleton. Microtubules are essential for the late phase of corneal epithelial wound healing, characterized mainly by cell mitosis. As yet. little is known about their function in the nonmitotic early phase of healing, but possibilities include the maintenance of cell shape and intracellular transport.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

After resurfacing a total corneal epithelial defect extending 2–3 mm beyond the limbus, conjunctival epithelium gradually loses goblet cells and transforms into a corneal-like epithelium. We examined the effect of topical retinoic acid on the reversal of transdifferentiation on nonvascularized corneas. Four months after total denudation of corneal epithelium using n-heptanol. rabbit corneas without vascularization received topical drops of 0.1% (wt/vol) all-trans retinoic acid in corn oil 3 times a day. Before treatment, the transdifferentiation was complete, as evidenced by the absence of goblet cells on the corneal surface using a topographical assay and routine histology. After treatment for 15days, goblet cells.reappeared 3 mm into the peripheral cornea, and extended in a centripetal density to 4.5 mm after 32 days. To prove that retinoic acid was not angiogenic. retinoid-bearing Elvax-40 pellets were implanted into normal corneal stroma. Taken together, these data indicate that vitamin A or retinoids may be an important factor in the modulation of conjunctival epithelial transdifferentiation.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Epikeratophakia is a rapidly evolving surgical procedure for the refractive correction of aphakia. Even when Snellen acuity after epikeratophakia is normal, patients often report a subjective degradation of the visual image through the surgically corrected eye. To further define visual performance in the patient with optically successful epikeratophakia, we examined contrast sensitivity in two patients surgically corrected for monocular aphakia. Contrast thresholds were measured over a range of spatial frequencies using both computer-generated sinusoidal gratings and a commercially available wall chart system. The eye with epikeratophakia in each case was compared with the opposite normal eye with comparable acuity. One patient was also tested prospectively in the same eye both before and after surgery. Data demonstrate a depression of the contrast sensitivity function in the middle and high spatial frequencies induced by the placement of an epikeratophakia lenticule when compared with the normal eye or contact lens-corrected, preoperative aphakic eye with comparable good acuity. These Findings may explain the subjective experience of epikeratophakia patients.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

A 58-year-old woman lost her left eye due to Aspergillus panophthalmitis four months after excision of a ptery-gium. The patient had received postoperative beta radiation and developed a scleral ulcer in the area of treatment from which no organisms could be cultured on two occasions. Because of the difficulty of diagnosing superficial mycotic infections of the eye, and because the treatment of so-called radiation scleritis may worsen fungal infections, ophthalmologists need to be aware of the potential infectious complications associated with the treatment of pterygia.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Pellucid marginal corneal degeneration is a bilateral disease characterized by a narrow band of corneal thinning localized 1–2 mm from the inferior limbus. The disease is diagnosed usually between 20 and 50 years of life, and its etiology remains obscure. During the clinical course and evolution of pellucid marginal corneal degeneration, acute hydrops with corneal edema in the lower half may develop (acute pellucid marginal corneal degeneration). However, since cases of acute pellucid marginal corneal degeneration are not frequently encountered in clinical practice, each new patient is evaluated ami managed with the utmost care to contribute to our better understanding of this disease. This is a report of two cases of acute pellucid marginal corneal degeneration that had a relatively favorable functional outcome when treated medically, so that corneal grafting was not necessary.

ISSN:0277-3740    

出版商:OVID    

年代:1988

数据来源: OVID