Arylsulfatase-cytochemical localization in lenses of normal and galactose-fed rats

Our laboratory is involved in studying the mechanism of repair in the ocular lens. As lysosomal enzymes have been shown to play an important role in tissue repair, we have been investigating the status of lysosomal enzymes, such as acid phosphatase and arylsulfatases, in the normal and injured lens. In the present investigation, we have examined the presence, distribution, and possible role of arylsulfatases (E.C. 3.1.6.1) in lenses of normal and galactose-fed rats. Arylsulfatases were localized in lenses using the cytochemical procedure described by Hopsu-Havu and Helminen (1974) using p-nitrocatechol sulfate as a substrate and then examined at the ultrastructural level. The reaction product resulting from arylsulfatase activity was mainly localized in the epithelial cells with very little activity in the cortical fibers. The intracellular activity was confined to lysosomes. Some extracellular activity was visible in the intercellular regions in both the epithelium and superficial cortex. With the progression of galactose-induced lesion in the epithelium the number of lysosomes exhibiting enzyme reaction product was found to have increased, and the lysosomes closely abutted the capsule. The biochemical assay indicated a considerable increase in the activity of arylsulfatases with the continuation of a galactose diet. The possible role of arylsulfatases in the normal and cataractous lens is discussed.

Ultrastructural cytochemistry of the ocular lens

Ultrastructural and cytochemical investigations of ocular lens have been difficult due to limited applicability of currently available techniques for the preparation of this tissue for such studies Several modifications in currently available techniques are being made in order to preserve the fine structure of the lens. In this report we present a modified method which provides good preservation of lens fine structure and allows cytochemical localization of enzymes in this tissue. Brief freezing permits preparation of thin slices of the lens which are subsequently incubated in the appropriate media for enzyme cytochemistry at an ultrastructural level. We have used this modified method for the localization of Na-K-dependent ATPase and the results are presented in this report.

Sodium-potassium--dependent ATPase. II. Cytochemical localization during the reversal of galactose cataracts in rat

The importance of enzyme Na-K-ATPase in the development of galactose-induced cataractogenesis is now well realized. In our recent studies we reported decreased level of activity of this enzyme with an increased duration of galactose feeding and the induced alterations in rat ocular lens. Our approach was to determine the level of Na-K-ATPase activity by ultrastructural cytochemical analysis of lenses and spectrophotometric analysis of the incubating media used for cytochemical localization as described by Ernst. Using these approaches, we have determined the activity level of this enzyme during the reversal phase of the galactose-induced injury to the lens. Our findings are presented in this report and show that the activity of Na-K-ATPase recovers rapidly and attains the normal level when the animals were transferred to Rat Chow diet after the establishment of mature cataracts resulting from galactose feeding. This study supports the previous biochemical and morphological findings that partial reversal of galactose-induced cataractous lens occurs upon discontinuation of feeding of cataractogenic agent galactose.

Vertical transmission of hepatitis B antigen in Taiwan

To determine the frequency of vertical transmission of hepatitis B antigen (HB5 Ag) from asymptomatic carrier mothers in Taiwan to their offspring, HB5 Ag was sought by radioimmunoassay and complement fixation. Of 158 babies born to carrier mothers, antigenemia developed in 63; 51 of these antigenemic babies had become antigen positive within the six months of life. Three inter-related factors were found to increase the risk that antigenemia would develop in the infant: a high maternal complement-fixation titer for HB5 Ag: presence of HB5 Ag in the baby's umbilical-cord blood: and antigenemia in siblings. In contrast to previous studies, these findings indicate that vertical transmission from carrier mothers frequently occurs, at least in Taiwan, and may partially explain Taiwan's high prevalence of HB5 Ag.