Various dogs from the treatment groups will be sacrificed and analyzed for enzymes, free radicals, lipids and lipid peroxides, aldehydes, vitamin A and E and fluorescent properties of the isolated lipopigments. New groups are being evaluated using monthly injections of mannitol as a blood-brain, blood-retinal barrier opening agent in conjunction with drug administration. Tissue cultures of RPE cells obtained from dogs with CCL, heterozygotes and normals will be established and used for basic studies as well as models for evaluating new treatments. The effects of high lipid or lipid peroxide concentrations in the culture medium and ways to prevent cellular damage will be studied. Sheep with ceroid-lipofuscinosis will be sent to the Univ. of Florida for electrophysiological (ERG, EEG, VEP, brain stem auditory potentials) testing. Later they will be sacrificed for biochemical and morphological studies. RPE cell lines will be established in culture. Preliminary experiments will be conducted on separating the various retinal cell types from affected sheep and dogs. Changes in fluorescent properties as a function of age will be studied in both animals by quantitative fluorescence microscopy. Differential solvent extractions are planned to coincide with the microscopic fluorescence to identify the several components of lipopigments. The rabbit model will continue to be used in evaluating the cytotoxic effects of numerous substances on retinal, ROS and RPE structure and function. Studies designed to test protection will also be conducted. In-breeding of a new retinal dystrophy in Swiss hounds has been successful. Enucleations will be performed at various ages in the offspring to determine the pathophysiological mechanism of retinal destruction.