Abstract
As a non-vascularized tissue, the cornea is unique from a biological point of view. It receives its nourishment by diffusion of fluids through the entire corneal substance. In trauma this diffusion may be disturbed leading to vascularization and loss of transparency.
Earlier many attempts were made to nourish the elements of tissue cultures and to increase their rate of proliferation in vitro. 1 The attempt to influence the regeneration of corneal defects by embryonic tissue extracts encountered many difficulties. Fischer 2 found that in tissue cultures in vitro the embryonic extracts could be replaced by an artificial medium in which amino acids furnished the building stones for the synthesis of protoplasm. Cystine, which seemed to function both as an energy-furnishing ingredient and as a growth catalyst, apparently played a major role in this medium. This special function of cystine is probably connected with its sulfur content, as free sulfhydryl groups often activate proteolytic systems in the process of growth.
Encouraged by Fischer's results the writer has made an attempt to influence the regeneration of experimental wounds of the cornea by administration of amino acids to this tissue in vivo. For the first experiment 36 guinea pigs were used. The technic employed was a modification of the method of Gundesen and Liebman. 3 Superficial vertical incisions were made across the cornea into the epithelium of both eyes by means of a Castroviejo double knife with blades 2 mm apart. The cornea was immediately stained with fluorescein and the epithelium between the two lines evenly abraded with a spatula. The corneae were periodically stained and the fluorescein-positive areas registered on a chart drawn on logarithm paper. The chart consisted of a ring symbolizing the limbus with a vertical double line in the center.
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