Diabetic-like corneal sensitivity loss in galactose-fed rats ameliorated with aldose reductase inhibitors.

This study investigated whether diabetic-like corneal sensory deficits occur in the galactose-fed rat model of diabetic ocular complications and if such deficits could be prevented using either of two structurally different aldose reductase (AR) inhibitors, CT-112 or AL-1576. S-D rats were randomly grouped to receive a diet of Purina chow with either 50% starch (n=25) or 50% D-galactose (n=65). Some of the galactosemic rats received either 0.25% CT-112 topically 3x daily (n=15) or 28 mg/kg body wt/day AL-1576 systemically (n=10). The control and untreated galactosemic rats in the CT-112 portion of the study received equivalent topical doses of the vehicle. Sensitivity measurements were made with a Cochet-Bonnet Aesthesiometer mounted on a micromanipulator. The filament was applied to the central corneal surface (mean pressure of 0.96 g/mm2) and viewed using a slit-lamp biomicroscope. Ten consecutive stimuli were conducted on each cornea and the average number of blink-responses was expressed as a percent of total stimuli effected. Mean initial corneal sensitivities were similar in all groups. Corneal sensitivity in the galactosemic rat was reduced (p<0.01) at each monthly measurement compared to control. Animals treated with CT-112 or AL-1576 showed a significant increase in the mean blink-response compared to untreated galactose-fed rats and did not differ significantly from controls towards the completion of the 7 month study. Animals treated with AL-1576 did not develop cataracts, whereas those treated topically with CT-112 and untreated galactose-fed rats developed bilateral nuclear cataracts within 3 weeks. This is the first study to demonstrate decreased corneal sensitivity in the galactose-fed rat model and its amelioration with AR inhibitors. Thus, aldose reductase, the first enzyme of the polyol pathway, may have an important role in the pathogenesis of decreased corneal sensitivity. The model could be useful for investigating the pathogenic mechanism(s) involved in reduced corneal sensitivity associated with diabetic keratopathy in humans.

Isolation and chromosomal localization of a cornea-specific human keratin 12 gene and detection of four mutations in Meesmann corneal epithelial dystrophy.

Keratin 12 (K12) is an intermediate-filament protein expressed specifically in corneal epithelium. Recently, we isolated K12 cDNA from a human corneal epithelial cDNA library and determined its full sequence. Herein, we present the exon-intron boundary structure and chromosomal localization of human K12. In addition, we report four K12 mutations in Meesmann corneal epithelial dystrophy (MCD), an autosomal dominant disorder characterized by intraepithelial microcysts and corneal epithelial fragility in which mutations in keratin 3 (K3) and K12 have recently been implicated. In the human K12 gene, we identified seven introns, defining eight individual exons that cover the coding sequence. Together the exons and introns span approximately 6 kb of genomic DNA. Using FISH, we found that the K12 gene mapped to 17q12, where a type I keratin cluster exists. In this study, four new K12 mutations (Arg135Gly, Arg135Ile, Tyr429Asp, and Leu140Arg) were identified in three unrelated MCD pedigrees and in one individual with MCD. All mutations were either in the highly conserved alpha-helix-initiation motif of rod domain 1A or in the alpha-helix-termination motif of rod domain 2B. These sites are essential for keratin filament assembly, suggesting that the mutations described above may be causative for MCD. Of particular interest, one of these mutations (Tyr429Asp), detected in both affected individuals in one of our pedigrees, is the first mutation to be identified within the alpha-helix-termination motif in type I keratin.

[Physical properties of an intraocular lens coated with diamond-like carbon film].

I have invented an intraocular lens (IOL) coated with diamond-like carbon film and have investigated its physical properties. Diamond-like carbon film is an ultrathin film which is composed of many carbon atoms and very few hydrogen atoms, and has properties very similar to diamond. I have measured the following properties of the polymethylmethacrylate (PMMA) plates or IOLs coated with diamond-like carbon film: light transmission curve, resistance against Nd:YAG laser capsulotomy, peel-off test, and contact angle. The plates or lenses are more ultraviolet-absorbing than uncoated PMMA plates, and PMMA plates coated with 50 nm-thick diamond-like carbon film have a light transmission curve very similar to that of a 25-year-old human crystalline lens. The pits and cracks due to Nd:YAG laser emission were smaller in the coated IOLs were more hydrophobic and oleophilic than uncoated IOLs. Diamond-like carbon film coated IOLs are thought to be very promising.

Ocular surface disorders in the critically ill.

Abnormalities of the cornea and conjunctiva occur in association with neurological diseases, nocturnal lagophthalmos, coma, infection, and mechanical ventilation. We investigated the incidence and causes of ocular surface disorders in critically ill patients. In a retrospective study, the presence of conjunctivitis and corneal erosion was determined by reviewing the medical charts of 143 mechanically ventilated patients (intensive care unit [ICU] stay > or =7 days). In the subsequent prospective study, 15 patients who had sedatives or muscle relaxants administered continuously for more than 48 h in the ICU were investigated. Corneal erosion was examined using a slit lamp once a day. Ocular surface disorder was found in 28 of the 143 patients (20%) whose ICU stay exceeded 7 days. The incidence increased with continuous sedation (35% vs 15%). The incidence also increased with continuous neuromuscular blockade (39% vs 11%). In the prospective study, nine patients (60%) developed corneal erosion. A patient's inability to fully close his or her eyes increased the incidence (P < 0.01) of corneal erosion. Protective eyelid taping was effective in preventing and treating the corneal erosion. In conclusion, the critically ill often develop ocular surface disorders, especially when sedated and immobilized. A close relationship was observed between these conditions and the inability to close one's eyes.

Core vitrectomy preceding triple corneal procedure in patients at high risk for increased posterior chamber pressure.

We evaluated the effectiveness of performing a core vitrectomy to prevent intraoperative posterior chamber pressure evaluation in eyes at high risk for development of this complication, prior to penetrating keratoplasty, extracapsular cataract extraction and posterior chamber lens (IOL) implantation. Results in 10 cases with core vitrectomy were compared with 10 cases without (controls); in all eyes with vitrectomy, a posterior chamber IOL was easily implanted but four eyes of the control group developed vitreous complications. Our results indicate that core vitrectomy does facilitate IOL implantation during a triple corneal procedure in eyes at increased risk of elevated posterior chamber pressure.

Effects of topical aldose reductase inhibitor CT-112 on corneal sensitivity of diabetic rats.

PURPOSE: To investigate whether the loss in corneal sensation observed in human diabetics could be duplicated in diabetic rats and if this abnormality could be prevented by topical instillation of an aldose reductase inhibitor (ARI), CT-112. METHODS: Rats were made diabetic by injection of streptozotocin. Some of these rats were treated with eye drops of CT-112 while others were treated with the same vehicle solution without ARI. Normal rats served as controls. Corneal sensitivity was measured by means of a Cochet-Bonnet aesthesiometer, using the blink reflex as an objective sign. Corneal changes in ultrastructure in diabetic rats were also observed. RESULTS: The corneal sensitivity of diabetic rats was significantly decreased and this change was prevented by ARI treatment. Ultrastructurally, degenerations of axons and mitochondria of the corneal nerve were seen in the diabetic rats and the ARI treatment prevented these morphological changes. CONCLUSIONS: It is clear that corneal hypesthesia occurs in diabetic rats as it does in human diabetics, and treatment with an ARI prevents this change. Along with the functional abnormality, the ultrastructural changes of corneal nerve also occur in diabetic rats, and they are prevented by ARI. These results strongly suggest that aldose reductase is involved in corneal hypesthesia and ultrastructural changes of corneal nerve in diabetic rats. These defects are ameliorated by aldose reductase inhibitor.

The use of synthetic Cecropin (D5C) in disinfecting contact lens solutions.

PURPOSE: Microbial keratitis caused by Pseudomonas aeruginosa is the most common contact lens associated corneal infection. Cecropins are microbicidal peptides isolated from the hemolymph of the Cecropia moth. Previous in vitro studies have demonstrated their efficacy against a broad spectrum of ocular pathogens. This study was designed: a) to evaluate the antimicrobial potency of three different contact lens solutions (Renu, Complete, and Opti-Free) against P. aeruginosa, and b) to evaluate the activity of the same contact lens solutions in combination with a synthetic cecropin analog, D5C, against the challenge organism in the presence of a soft contact lens. METHODS: A virulent strain of P.aeruginosa isolated from a case of ulcerative keratitis was used in the study. Three different concentrations of bacteria (10(3), 10(5) and 10(7) CFU/mL) were inoculated into the contact lens solutions and into buffered saline, which was employed as a control. The samples were incubated at 27 degrees C, and at time 0, 30, and 90 minutes, 24, 48, and 72 hours, and aliquots of the test solutions were plated and subcultured on nutrient agar. After 24 hours of incubation at 37 degrees C, colonies observed on the nutrient agar plates were counted. To study the antimicrobial efficacy of D5C (100 micrograms/mL), we used the identical test series and assay, adding a soft contact lens to the solutions and a larger inoculum of bacteria (10(9) CFU/mL). RESULTS: After 72 hours, all of the contact lens solutions tested sterilized 10(3) CFU/mL of P. aeruginosa. At 10(7) CFU/mL, they yielded greater than 2 logs of killing of the bacteria, but the solutions were not sterilized. The addition of D5C (100 micrograms/mL) to the contact lens solutions yielded greater than 3 logs of killing with a larger inoculum of bacteria in the presence of the soft contact lens. CONCLUSION: The contact lens solutions tested were effective against P. aeruginosa at 27 degrees C for up to 72 hours with an inoculum of 10(3) CFU/mL. The addition of D5C augmented their antimicrobial activity in the presence of the contact lens.

Reversal of abnormal corneal epithelial cell morphologic characteristics and reduced corneal sensitivity in diabetic patients by aldose reductase inhibitor, CT-112.

PURPOSE: A randomized clinical study was undertaken to determine whether a topically applied aldose reductase inhibitor, CT-112, was capable of reversing the abnormal morphologic characteristics of corneal epithelial cells, as well as the reduced corneal sensitivity, in diabetic patients. METHODS: Thirty-nine diabetic patients were randomly divided into two groups: one group was treated with topical aldose reductase inhibitor (CT-112) in an ophthalmic preparation, and a control group was treated with the same preparation without the inhibitor. Specular microscopy was performed to analyze the morphologic characteristics of corneal epithelial cells before and after the treatment. Corneal sensitivity was measured by means of the Cochet-Bonnet esthesiometer. RESULTS: The anterior surface area of superficial cells in the group treated with CT-112 was significantly decreased from a mean value of 881 to 728 microns2 (P < .0001), whereas the control group showed no significant changes. Corneal sensitivity remained decreased in the control group, whereas that in the group treated with CT-112 significantly improved, from 5.36 to 1.37 g/mm2 (P < .0001). CONCLUSIONS: These results indicate that treatment with topical CT-112 is capable of reversing abnormal morphologic characteristics of corneal epithelial cells and reduced corneal sensitivity in diabetic patients.

[Two cases of Werner's syndrome treated with penetrating keratoplasty].

Cataract is one of the typical ocular manifestations of Werner's syndrome. In contrast to cataract in normal elderly persons, cataract in patients with Werner's syndrome is known to be associated with degenerative corneal changes after cataract surgery. Among the corneal changes bullous keratopathy occurs in almost 100% of patients with Werner's syndrome after cataract surgery. Although penetrating keratoplasty appears to be the best treatment for bullous keratopathy, there have been few reports on bullous keratopathy in patients with Werner's syndrome. Here we report two patients with Werner's syndrome who underwent penetrating keratoplasty for the treatment of bullous keratopathy. In both cases, visual acuity was improved, suggesting that penetrating keratoplasty is a recommendable treatment for bullous keratopathy in patients with Werner's syndrome.

Comparison of the effects of intraocular irrigating solutions on the corneal endothelium in intraocular lens implantation.

We conducted a randomised prospective controlled study to determine the effects of a glucose glutathione bicarbonate solution (BSS Plus) and a citrate acetate bicarbonate solution (S-MA2) on the corneal endothelium in patients undergoing extracapsular cataract extraction with posterior chamber lens implantation. One eye of each patient was randomly assigned to receive BSS Plus, and the other eye to receive S-MA2. BSS Plus caused significantly less corneal swelling on the first postoperative day than did S-MA2. There was no difference between the two solutions in their effect on corneal thickness one week and one month postoperatively. Computer assisted morphometric analysis of wide-field specular microscopic photographs demonstrated minimal changes in endothelial morphological characteristics in the eyes irrigated with BSS Plus. By comparison S-MA2, caused a significant loss of endothelial cells and a marked reduction in the figure coefficient. These results indicated that BSS Plus has a clinical advantage over S-MA2 with respect to the corneal endothelium.

Vitamin A eyedrops for superior limbic keratoconjunctivitis.

We treated 12 patients with superior limbic keratoconjunctivitis with topical vitamin A (retinol palmitate) eyedrops. After a follow-up period of at least three months, this therapy was found to be effective, to a varying extent, in ten patients (83%). Superior limbic keratoconjunctivitis lesions did not recur in these patients as long as topical application was continued.

Aldose reductase inhibitor (CT-112) eyedrops for diabetic corneal epitheliopathy.

We treated two diabetic patients with corneal epithelial disorder that resisted conventional medical therapy with topical CT-112 (5-[3-ethoxy-4-pentyloxyphenyl]-2,4-thiazolidinedione), a newly synthesized aldose reductase inhibitor. One patient had developed recurrent corneal erosion after vitrectomy and the other had spontaneously developed superficial punctate keratopathy. The corneal lesion in each patient responded to topical CT-112 in two to four weeks and was almost cleared within two months. A similar corneal lesion recurred in both patients soon after CT-112 was discontinued, but it disappeared again when the drug was resumed.