Keiko Tsuzuki

Microstructure and glycosaminoglycan ratio of canine cornea after reconstructive transplantation with glycerin-preserved porcine amniotic membranes.

OBJECTIVE Although amniotic membranes of canine, feline, and equine species have some advantages as corneal transplantation material in many canine ocular diseases, their softness, thinness, and low availability can pose problems. As an alternative, the more abundant porcine amniotic membranes may be used. This paper describes the use of glycerin-preserved porcine amniotic membranes in corneal transplantation in eight normal dogs. METHOD A 0.4-mm deep recipient bed in the axial cornea of the OS of all dogs was created using an 8-mm Barron radial vacuum trephine. The recipient bed was then filled with amnion, and the entire cornea was covered with another piece of the glycerin-preserved membrane. The ocular signs evaluated were corneal opacity and corneal vascularization. The dogs were euthanized on days 5, 10, 20, or 40 after surgery, and samples were collected to evaluate corneal thickness, parenchymal cell number, mean collagen fibril diameter, collagen fibril content and the glycosaminoglycan (GAG) ratio. RESULTS Corneal opacity was observed immediately after surgery. Restoration of corneal transparency, regression of corneal vascularization, and visualization of the pupil and iris were noted on day 40. CONCLUSIONS The clinical observations were supported histologically by regained corneal thickness, parenchymal cell number, mean collagen fibril diameter, collagen fibril content, and GAG ratio, suggesting that this technique may be a novel method for the treatment of ocular surface disorders.

Investigation of fellow eye of unilateral retinal detachment in Shih-Tzu.

OBJECTIVE To investigate disease in the fellow eye, and consider the relation to rhegmatogenous retinal detachment (RRD) in Shih-Tzus. ANIMALS STUDIED The fellow eyes of 49 Shih-Tzus (27 male, 22 female; median age: 6.8 years) with unilateral RRD diagnosed by funduscopy or ultrasonography at Rakuno Gakuen University Teaching Animal Hospital were assessed in this study. PROCEDURES Ophthalmic examinations (including menace response, pupillary light reflex, slit-lamp biomicroscopy, and funduscopy) were performed in the subjects. Electroretinography was performed in 12 eyes that developed retinal degeneration. Maximum follow-up period was 42 months. RESULTS Cataracts and vitreous opacity were observed in 26 (53%) and 32 eyes (65%), respectively, by slit-lamp biomicroscopy. Retinal degeneration with various degrees of hyper-reflectivity of the tapetal fundus and/or attenuation of retinal vessels was observed in 35 eyes (71%) on funduscopy. A reduction of amplitude in rod, standard combined and 30 Hz flicker electroretinogram was detected in 5 (42%), 10 (83%), and 6 eyes (50%), respectively. During the follow-up period, RRD was detected in six eyes. CONCLUSION Retinal degeneration was frequently detected by funduscopy and electroretinograms in the fellow eye in Shih-Tzus with RRD. In our subjects, vitreous degeneration was also observed frequently. It has been reported that peripheral retinal degeneration is one of the causes of RRD associated with vitreous degeneration in humans. We assume that primary retinal degeneration with secondary vitreous degeneration is one of the causes of RRD in Shih-Tzus.

A preliminary study of direct application of atelocollagen into a wound lesion in the dog cornea.

Purpose: To evaluate the effectiveness of atelocollagen for canine corneal wound healing. Materials and Methods: Atelocollagen was used to fill a transplant bed in the central cornea, which was then covered with a contact lens. The wound healing process was analyzed clinically, morphologically, and biochemically. Results: At the early healing stage, both the pupillary zone and details of the iris were observed. The stromal collagen fibrils normalized in a time-dependent manner. Type III collagen in the wound area was detected faintly throughout the experimental period. Conclusions: This novel method is advantageous for accelerating wound healing without causing inflammation.