Assessment of Variability in Some Lysosomal and Soluble Enzyme Activities in Corneal Epithelium from Slaughterhouse Bovine Eyes

Abstract

The corneal epithelium was scraped from bovine eyes (Hereford or Holstein) within 3 h post mortem. The mitochondrial lysosomal fraction of the cells was assayed for hexosaminidase (HEX) and acid phosphatase (AP), and the membrane-soluble fraction for lactate dehydrogenase (LDH) and leucine arylamidase (LAA) activity. Pairs of eyes with clear corneas showed variances ( ± 1 SD, n = 10 pairs) of ± 62, ± 57, ± 72 and ± 31% in the four enzyme activities (HEX, AP, LDH, LAA). Selection based on age (corneal diameter) reduced the variance to ± 41, ± 37, ± 39 and ± 30%. Additional selection for corneal surface wettability reduced variances to ± 26, ± 21, ± 22 and ± 26% in the activities. The latency of the lysosomal enzymes (HEX, AP) increased substantially with eye selection.

Influence of Tissue Sample Dimensions on the Swelling of the Corneal Stroma

“…Since corneal dimensions (and thus tissue mass) can be expected to change with eye size and animal age [9,20], the eyes were sized and selected by measurements of the horizontal corneal diameter to be 23.5-25.0 mm. Only those eyes which had a moist corneal surface on receipt were used since such eyes are less likely to be affected by desiccation, which can have a substantial effect on the corneal epithelium [9,21] and cornea [22]. For such size-and quality-selected eyes, corneal samples have been found to have an average hydration of 3.5 ± 0.2 g ELO/g dry mass (77.9 ± 0.7% water content) [23].…”

Impact of hypotonic solutions on the stromal swelling, lactate dehydrogenase and aldehyde dehydrogenase activity of the keratocytes of the bovine cornea

“…within a maximum of 2.5 h postmortem. To minimise inter-sample variance, eyes were selected based on the quality of appearance of the corneal surface, and for age based on the horizontal corneal diameter and central corneal thickness (Doughty, 1996;Doughty et al, 1995a,b). The horizontal corneal diameter measurements were all between 27.5 and 29.5 mm.…”

Some Kinetic Properties of Lactate Dehydrogenase Activity in Cell Extracts from a Mammalian (Ovine) Corneal Epithelium

“…The eyes were assessed for quality and size (Doughty, 1996(Doughty, , 1997 to select those with a 1j or 2j score for appearance and wetability, a horizontal corneal diameter of 23 to 25n5 mm and had a central corneal thickness of 632 to 756 µm (see results).…”

“…The terminal enzyme activity responsible for this (lactate dehydrogenase, LDH) has been measured in corneal epithelial cell extracts (Kuhlman and Resnick, 1958 ;Futterman and Kinoshita, 1959 ;Delbruck, 1963 ;So$ llner et al, 1966 ;Morisue, Shiba and Hoshino, 1967 ;Reim et al, 1971 ;Kaha! n and Ottovay, 1975 ;Doughty, 1996Doughty, , 1997 or epithelialendothelial cell extracts from corneas (Moore and Wortman, 1959 ;Graymore and McCormick, 1966 ;Graymore, 1966 ;Graymore and Power, 1967). Despite its repeated measurement, few details however appear to have been published on the actual quantities of the enzyme present in the corneal epithelium, on its essential properties or its localisation.…”