Immunohistochemical Distribution of Heme Oxygenase Isoenzymes in Developing Rat Retina

PURPOSE: To analyze and compare the immunohistochemical distributions of HO-1 and HO-2 with the developmental process of retina, focusing on the time of birth and opening eyes because it is the time of the exposure to hyperoxia and light exposure. METHODS: The retina of 16-day-old embryo, 18-day-old embryo, 20-day-old embryo and postnatal rats at 0 day, 5 days, 10 days, 15 days, 20 days, 1 month, 2 months, 3 months were examined by hematoxylineeosin staining and immunohistochemistry of HO-1 and HO-2. RESULTS: Similar distribution of HO-1 and HO-2 from embryo to mature retina were observed. It was observed that HO-1 and HO-2 was contained in ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and pigment layer of the mature retina. In the developmental process, reactivity was observed in the cell body of ganglion cells after 0 day of its birth. The reactivity was increased after 5 days of its birth, staining was observed in nerve cell and nerve fiber of ganglion cell layer, inner plexiform layer, inner segment of neuroblastic layer, pigment layer at this time. Reactivity of ganglion cell layer and pigment layer was increased intensively after 15 days of its birth and weak reactivity in some of horizontal cells and amacrine cells in inner plexiform layer was observed. The same distribution as that of mature retina was observed after 20 days of its birth. CONCLUSIONS: HO-1 and HO-2 expression was temporally and spatially correlated with the normal development of retina in rats. HO was concerned with the structure and function of retinal development by the activation of its products and with anti-oxidant mechanism on the time of birth and opening eyes.

The Effect of 0/1% Dexamethasone on Repair Process of Eithelial Basement Membrane after Corneal Alkali Wounds: Electron Microscoic Examination

An intact basement membrane which provides a firm attachment of basal epithelial cells to the maintain the corneal integrity in alkali wound healing. Despite many therapeutic trials tested, the fate of present investigation, the repair process of basal epithelium and its basement membrane was evaluated morphologically by utilizing a transmission electron microscope. New Zealand white rabbits, weighing 2.5kg, total of 16(16 eyes), were used in this experiment. Initial epithelial wounds were induced by applying a 5.5mm round filter paper, soaked in 1N NaOH, put on the central cornea for 60 seconds. Animals were divided into two groups and treated with 0.1% dexamethasone in the treated group and with balanced salt solution(BSS) in the control eyes q,i,d. for 8 weeks;. In control eyes, the basement membrane started focal disruption at 2 days, became the worst state at 4 weeks, and regained the normal integrity at 8 weeks after initial alkai damage, In dexamethansone-treated eyes. the basement membrance structure was fairly well visible up to 4 weeks and was almost completely disappeared at 8 weeks after intial alkali wounds.

Morphological Studies on Fuchs`Dystrophy

Light andelectron microscopic findings of Fuchs`dystrophy were examined in a corneal button obtained following a penetrating keratoplasty. In light microscopic study, an avascular connective tissue was observed between the epithelial basement membrane and Bowman`s layer. Fibroblast-like cells scattered on the denuded surface of the Descemet`s membrane were found in a flat-mounted specimen examined after alizarine red and tryphan blue staining. A slightly thickened Descemet`s membrane covered with the disorganized endothelium was observed in a electron microscopy. Swollen organelles and vacuoles in the cytoplasm were found as an internal structure of the endothelium.

Effects of 0.1% Dexamethasone on Experimental corneal Epithelial Healing Following Alkali Wounds

The effect of topical steroid on corneal alkali wound has been controversial due to a complexity of its mechanism and a risk of ulceration and perforation. In this study, the effect of topical 0,1% dexamethasone on corneal epithelial wound healing following alkali burn was evaluated quantitatively. 22 eyes wounded by alkali burn out of 22 white rabbits were divided into 3 groups ; A group treated with topical 0.1% dexamethasone for eight weeks, B grouptreated with topical 0.1% dexamethasone for the first one week followed by another seven weeks without treatment, C group with no treatment served as a control. The area of corneal epithelial defect was examined at 6, 18, 30, 42 hours following corneal alkali wound for initial wound healing and examined every other day from 4 days to 48 days following corneal alkali wound for late wound healing. In this study, it was found that topical 0.1% dexamethasone delayed corneal epithelial healing following corneal alkali burn in both stage of initial and late wound healing.

A Clinical Report on the Use of Autogenous Levator Muscle Transposition and Bilateral Frontalis Sling for Ptotic lid in Neurogenic Blepharo-ptosis

The authors performed frontalis sling operation using autogenous levator muscle transposition for ptotic lid between February, 1989 and March, 1993. Four cases were Marcus-Gunn ptosis and one case was paralytic ptosis with aberrant regeneration in patient with oculomotor nerve palsy. The postoperative surgical results were satisfactory cosmetically.