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  • Author or Editor: Glenwood G. Gum x
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Summary

The anterior chambers in 16 dogs with normotensive eyes and 3 Beagles with glaucomatous eyes were treated with 0, 25, 50, or 100 IU of bovine testicular hyaluronidase. Aqueous outflow resistance was then determined by constant-pressure perfusion of 0.9% NaCl solution for 30 or 60 minutes. In normotensive eyes, 25, 50, or 100 IU of hyaluronidase significantly (P < 0.02) increased the rate of constant-pressure perfusion compared with that of untreated eyes during 30- or 60-minute perfusions. Treatment of glaucomatous eyes with 25, 50, or 100 IU of hyaluronidase did not significantly increase the rate of constant-pressure perfusion over controls during a 30-minute perfusion.

Bovine testicular hyaluronidase at all doses removed the staining of colloidal iron from the trabecular meshwork in normotensive eyes. In Beagles with glaucoma, the trabecular meshworks remained stained with colloidal iron when treated with the hyaluronidase, which suggested that some glycosaminoglycans were resistant to this enzyme's action.

Free access
in American Journal of Veterinary Research

SUMMARY

A new topically administered anhydrase inhibitor, MK-927, was evaluated for its ocular hypotensive activity in normotensive and glaucomatous Beagles. Single- and multiple-dose studies were performed. Six concentrations of the drug were evaluated in the single-dose study and the 2% solution was used for multiple-dose evaluation. The decrease in intraocular pressure (iop) was greater in glaucomatous Beagles at the higher concentrations of the drug. The 2 and 4% solutions of MK-927 significantly lowered iop (mean, 5 mm of Hg; sem ± 1.6 and sem ± 1.2, respectively) in normotensive and glaucomatous Beagles. In the multiple-dose study, iop was significantly decreased in the normotensive (mean, 4 mm of Hg; sem ± 0.74) and glaucomatous Beagles (mean, 9 mm of Hg; sem ± 1.2). The maximal effect was observed by day 4. A contralateral effect was found in glaucomatous Beagles, with the maximal effect on day 4.

Free access
in American Journal of Veterinary Research

SUMMARY

Topically applied demecarium bromide (0.125 and 0.25%) and echothiophate iodide (0.125 and 0.25%) solutions were evaluated in Beagles with nor-motensive eyes and Beagles with inherited glaucoma. In single-dose studies, the effects of intraocular pressure (IOP) and pupil size (PS) were measured in eyes before drug treatment and in drug- and nondrug-treated eyes. Both concentrations of the 2 drugs induced long-term miosis and decrease in IOP in nor-motensive eyes of Beagles and of eyes of Beagles with inherited glaucoma. Demecarium bromide (0.125 and 0.5%) decreased IOP for 49 and 55 hours, respectively. Echothiophate iodide (0.125 and 0.5%) reduced IOP for 25 and 53 hours, respectively. The miosis associated with both concentrations of the 2 drugs generally paralleled the decreases in IOP.

Free access
in American Journal of Veterinary Research

SUMMARY

The Mackay-Marg, Tono-Pen, and Challenger applanation tonometers were evaluated in vivo in 12 clinically normal eyes of 6 dogs. Tonometric measures of intraocular pressure (iop) were compared with closed manometric iop measurements from the anterior chamber of anesthetized dogs. The tonometers were evaluated at iop that ranged from 5 to 100 mm of Hg. The Mackay-Marg tonometer was the most reliable instrument when evaluated at iop from 5 to 100 mm of Hg (r 2 = 0.996) and from 10 to 30 mm of Hg (r 2 = 0.962). The Tono-Pen tonometer was also reliable (r 2 = 0.967) over the range of iop, but consistently overestimated iop at lower pressures and underestimated iop at higher pressures. The Mackay-Marg and Tono-Pen measurements were essentially linear. When evaluated from 10 to 30 mm of Hg, r 2 was 0.828 for the Tono-Pen tonometer. The Challenger tonometer, although reliable over the full range of iop (r 2 = 0.965), proved to be less accurate, as indicated by lack of a good linear equation.

Free access
in American Journal of Veterinary Research