摘要:

Corneal endothelial wound healing in living rabbit eyes after mechanical scrape (MS) and transcorneal freeze (TCF) injury was studied using tandem scanning confocal microscopy (TSCM). MS injury was created on the central corneal endothelium with an olive tip cannula; TCF injury was created using a 3-mm-diameter stainless steel probe cooled with liquid nitrogen. In vivo observation of wound healing using TSCM was correlated with scanning electron microscopy (SEM) for fixed tissues. At 6 h after MS, migrating endothelial cells at the leading edge showed lamellipodial processes on in vivo TSCM and SEM. After 24 h, the denuded area was almost fully resurfaced by migrating endothelial cells showing wide spaces between nuclei by TSCM. After 28 days, resurfaced endothelial cells showed normal hexagonal mosaic appearance with enlarged cells by TSCM and SEM. TCF injury produced fibroblastic changes in the endothelial cells with elongation and spreading by 24 h after injury. After 3 days, the wounded area was resurfaced with two cell types: (a) migrating endothelial cells at the peripheral area, which appeared polygonal in shape with wide intracellular spaces and (b) fibroblast-like cells at the center of the wound, which formed a retrocorneal fibrous membrane (RCFM). The RCFM was posteriorly covered with normal endothelium after 28-60 days. TSCM of the stroma demonstrated spindle-shaped, activated keratocytes migrating into the wounded stroma at 3-14 days. In conclusion, TSCM allows viewing of dynamic four-dimensional morphologic changes (x, y, z, and time) during in vivo cellular repair of corneal wound healing after either MS or TCF injury.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

We examined the effects of doxycycline hyclate on epithelial healing in vivo in the rabbit alkali-burn model. Twelve 2–3-kg Dutch belted rabbits were divided into three groups and received standard bilateral alkali burns (1 N sodium hydroxide for 30 s in an 11-mm circular plastic well). In group 1, two rabbits (four eyes) served as untreated controls. In group 2, five rabbits (10 eyes) received doxycycline hyclate (1.5 mg/kg) orally daily for 14 days. In group 3, five rabbits (10 eyes) received doxycycline hyclate (5 mg/kg) orally daily for 14 days. The epithelial defects were drawn and photographed on alternate days, after fluorescein staining. At conclusion, extracts of the corneas were evaluated for collagenase activity. At 14 days, the mean percentage of epithelial defects results in groups 1–3 were 50.0, 50.7, and 7.1%, respectively. Using the Wilcoxon rank sum test (two tailed), the differences were found to be statistically significant (p=0.0015). Preliminary data indicated that oral doxycycline administration also decreased the collagenase activity in corneas obtained from these animals. Our preliminary findings indicated that systematically administered doxycycline hyclate, 5 mg/kg/day, promotes corneal reepithelialization in the rabbit alkali-burn model, a result, perhaps, of the drug's ability to inhibit excessive collagenase activity.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

We investigated the altered immunolocalization of the components of epithelial basement membrane (BM) in rats with alkali burns of the cornea. Type IV collagen, laminin, and fibronectin were immunohistochemically stained in the alkali-burned corneas after various intervals. Linear laminin immunoreactivity, which represented the localization of the BM, was interrupted, probably by epithelial enzymes, under the regenerating epithelium after 24 h. A normal configuration was restored on day 7, when the central corneal BM showed a type IV collagen immunoreactivity that was not detected in BM of normal cornea. The exact cause of the development of type IV collagen immunoreactivity in the healing BM was not determined. Laminin, type IV collagen, and fibronectin, which were not detected in normal stroma, were all detected in the healing corneal stroma with repopulated keratocytes. Moreover, the BM zone under the regenerating epithelium showed fibronectin immunoreactivity on days 5–14. Distribution of these components of BM seemed to be normal 2 months postburn. The alteration of BM components is thought to be an important marker of the healing process in corneas burned with alkali.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

We examined the effects of the immunotoxin 260F9 Mabrecombinant ricin A (developed against human breast carcinoma) on proliferating and confluent human corneal epithelium (HCE) cells in vitro. HCE cells derived from explants of discarded human donor corneoscleral rims were established as proliferating and confluent cell cultures, and were exposed continuously for 7 days to immunotoxin. Final cell counts at day 7, and thymidine uptake measured at days 1 and 7 postexposure, showed >95% suppression of proliferating cells at an immunotoxin concentration of 10 ng/ml, with confluent HCE cells relatively unaffected. This immunotoxin may prove useful in treatment of proliferative ocular epithelial diseases such as epithelial downgrowth or squamous cell carcinoma of the ocular surface.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

An evaluation of the final “sutures out” postoperative astigmatism in two groups of keratoconus patients undergoing penetrating keratoplasty is presented. Group I consists of a retrospective evaluation of keratoconus patients who underwent penetrating keratoplasty without using the Troutman Keratometer prior to suturing the button into position. Group II patients had their donor button rotated in the recipient bed until approximate sphericity was indicated by a circular reflex from the Troutman Keratometer before suturing into position. The mean final astigmatism with all sutures removed from Group I was 4.64, SD 1.89, and for Group II 2.27, SD 1.27. Selective positioning of the donor button using the Troutman Keratometer leads to a significant reduction in the final sutures out astigmatism in patients undergoing penetrating keratoplasty for keratoconus.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

A prospective randomized clinical study was performed to see the effect of donor-recipient corneal size on the ultimate refractive error induced in keratoconus at our facility. The patients were randomly divided into two groups, A and B. In Group A, the difference in size between the donor and the recipient cornea was 0.25 mm (18 patients). In Group B, the difference in size between the donor and the recipient cornea was 0.50 mm (20 patients). Both groups underwent the surgical procedure with the same surgeon (M.A.J.) and the same technique. Two months after suture removal, keratometry readings and refractive errors induced were compared. The mean keratometry reading in Group A was 43.3 diopters; in Group B, the reading was 44.8 diopters. There was a mean difference of 1.5 diopters between the two groups (p=0.01). The mean refractive error in terms of spherical equivalent in Group A was – 1.55 diopters and in Group B was –3.33 diopters. There was a difference of –1.8 diopters between the two groups (p<0.05).

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

We found corneal lesions of West Indian punctate keratopathy in 128 of 2,048 patients examined in a general eye clinic in Grenada, West Indies. Of these, 125 were Black, two were Indians (Hindu), and one a White female. The lesions occurred in asymptomatic persons with no history of trauma or recurrent erosions. Males were affected more than females, and older adults more than children. The condition was usually unilateral but occasionally bilateral, with one to four lesions in the intrapalpebral fissure in a paracentral location. The lesions were round, discrete, white to yellowish-gray dots 0.2–0.6 mm in size located at the level of the epithelial basement membrane and Bowman's layer. No vascularization nor other anterior membrane disorders were observed. Corneal biopsies of 11 patients were studied by histopathologic and immunoperoxidase techniques. Histopathology revealed areas of lipid positive material in Bowman's layer and adjacent corneal stroma. The epithelium showed basal cell edema, degeneration, and irregular thickening of the basement membrane. Immunoperoxidase studies did not contribute any new information about these lesions.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Topical cyclosporin A was used in the management of 43 patients with a variety of anterior segment inflammatory disorders that had failed corticosteroid treatment. Treatment with topical cyclosporin A ranged from 1 week to 43 months, with a mean treatment period of 13 months. Thirty-five patients (81%) with disorders including highrisk keratoplasty, atopic and vernal keratoconjunctivitis, ligneous conjunctivitis, ulcerative keratitis, and Mooren's ulcer had a beneficial result, with resolution, reduction, or prevention of inflammation. Six patients (14%) with scleritis, ocular cicatricial pemphigoid, or endotheliitis showed no clinical improvement. Two patients (5%) had significant ocular discomfort, and the drug had to be discontinued in them. None of the other patients developed local side effects. Twenty-seven of these patients were followed with serial cyclosporin A blood levels and serum creatinine. None of these patients developed measurable drug blood levels or renal toxicity.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Plasmin was found to degrade the fibronectin (Fn) mesh produced by cultures of normal rabbit corneal fibroblasts, cause breakdown of F-actin-containing microfilament bundles (“stress fibers”), and increase levels of active type I interstitial collagenase (MMP-1) in the medium. Fibroblast cultures derived from alkali-burned, ulcerating rabbit corneas also responded to plasmin by secreting collagenase, detected only in active form. Moreover, harvests from organ cultures of ulcerating corneas not only had higher levels of urokinase-like plasminogen activator (uPA) than normal cultures but also had higher levels of Fn degradation fragments. The results are consistent with reports that indicate that perturbation of the α5β1, integrin (Fn) receptor by proteolytic fragments of Fn causes the increased synthesis and secretion of MMP-1. The uPA/ plasmin system, therefore, might have an important role in regulating collagenase synthesis, secretion, and activation during wound remodelling and stromal ulceration.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

We examined the water retentive properties of hyaluronan because of its reported therapeutic effect in the treatment of dry eye. Hyaluronan dose dependently retarded water loss from a solution kept at constant temperature and humidity. Similarly, water loss was retarded when hyaluronan was placed atop an agar gel. These decreases in water loss were not related to changes in the molecular weight of hyaluronan. Unlike the in vitro models, the evaporation rate from the tears in normal subjects initially increased following the topical application of hyaluronan, and continued a higher rate than with the vehicle. These results suggest that hyaluronan enhances water retention on the corneal surface, and probably increases corneal wettability. Accordingly, hyaluronan eye drops may be useful in the treatment of dry eye.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID