The effects of gentamicin, tobramycin and the fluorquinolone, ofloxacin on corneal epithelial wound healing were determined using an in vitro model of wound healing. Wounds were created in rabbit corneal epithelial cultures which were then exposed to various concentrations of the antibiotics. Effects on wound healing were measured by comparing migration rates between 6 and 18 hours and wound areas at various antibiotic concentrations over 36 hours. Gentamicin at concentrations of 0.5, 1.0, 1.5 and 2.0 mg/ml was found to statistically significantly effect wound healing compared to controls. Tobramycin on the other hand was found to have minimal effect on wound healing up to 2.0 mg/ml. Ofloxacin at concentrations greater than or equal to 0.05 mg/ml had statistically significant effects on wound-healing.
Steroid metabolism studies have yielded evidence of 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity in corals. This project was undertaken to clarify whether there are multiple isoforms of 17beta-HSD, whether activity levels vary seasonally, and if zooxanthellae contribute to activity. 17Beta-HSD activity was characterized in zooxanthellate and azooxanthellate coral fragments collected in summer and winter and in zooxanthellae cultured from Montipora capitata. More specifically, 17beta-HSD activity was characterized with regard to steroid substrate and inhibitor specificity, coenzyme specificity, and Michaelis constants for estradiol (E2) and NADP+. Six samples each of M. capitata and Tubastrea coccinea (three summers, three winters) were assayed with E2 and NADP+. Specific activity levels (pmol/mg protein) varied 10-fold among M. capitata samples and 6-fold among T. coccinea samples. There was overlap of activity levels between summer and winter samples. NADP+/NAD+ activity ratios varied from 1.6 to 22.2 for M. capatita, 2.3 to 3.8 for T. coccinea and 0.7 to 1.1 for zooxanthellae. Coumestrol was the most inhibitory of the steroids and phytoestrogens tested. Our data confirm that corals and zooxanthellae contain 17beta-HSD and are consistent with the presence of more than one isoform of the enzyme.
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