Differences between two fractions of glycosaminoglycans of the corneal stroma in their structural relation to collagen.

Glycosaminoglycans (GAG) of bovine cornea were sequentially extracted by 0.15 M NaCl and by 1 M CaCl2, pH 8. The amounts of hexosamine (HexN) and hexuronic acid (HexUA), specific hexoses (Hex), and protein were determined in the extracts.

Studies on the cornea. X. Incorporation of 14C-glucosamine into glycosaminoglycans and glycoproteins of elasmobranch corneas, extractability of these components and morphological effects of such extractions.

Incorporation of 14C-glucosamine into dogfish (Squalus acanthias) corneas occurs primarily in the glycosaminoglycans (GAG) and glycoproteins (GP) extractable with elasmobranch Ringer's solution but the rate at which this component can be extracted varies inversely with the age (size) of the fish. Whereas this fraction represents only one-fourth of the total hexosamine (Hex-N) it contains nearly three-fourths of the newly incorporated 14C-glucosamine. The CaCl2-extractable HexN contains only 13% of the incorporated radioactivity.

Some biochemical aspects of light effects on transparent eye tissues.

The usefulness of biochemical studies on effects of light on transparent tissues of the mammalian eye is discussed in relation to the possible role of photobiological phenomena in aging and pathology of the eye. Particular emphasis is on effects of light on interaction between different cellular constituents of the corneal stroma which appear as a factor in regulation of the corneal metabolism. Daylight filtered through the walls of glass vessels was found to depress the incorporation of 14-C glucosamine into keratansulfate fraction of the bovine corneal stroma which appears not to be bound to collagen fibrils as it is extracted by 0.