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  • Author or Editor: Elizabeth A. Morrison x
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Abstract

Objective

To investigate the mechanism by which pilocarpine causes increased aqueous humor (AH) flare, hypotony, and miosis in dogs.

Animals

6 dogs with normal eyes.

Procedure

Both eyes of each dog were treated topically with a 2% solution of pilocarpine, and 1 eye of each dog was additionally treated with commercially available ophthamic solutions. Breakdown of the blood-aqueous barrier (BAB) was quantitated in each eye, using laser flaremetry to measure AH flare. Intraocular pressure and pupil size were also measured.

Results

Pilocarpine caused increased flare from BAB breakdown that was inhibited by the drugs tested. Inhibition (most to least) of BAB breakdown was flurbiprofen more than diclofenac, proparacaine, or suprofen, which were more than 0.125 or 1.0% prednisolone. Inhibition appeared dose-dependent and caused consensual inhibition in the contralateral eye. Intraocular pressure was decreased only in proparacaine-treated eyes and increased in eyes treated with nonsteroidal anti-inflammatory drugs (NSAID). Flurbiprofen and proparacaine were the most effective at blocking miosis.

Conclusions

Pilocarpine produced a predictable, reproducible BAB breakdown in dogs. Miosis and increased AH flare were inhibited equally by proparacaine or NSAID, suggesting that these signs were caused by neuropeptide release into the AH from antidromic stimulation, which subsequently triggers prostaglandin production. Hypotony was inhibited only by anti-inflammatory drugs.

Clinical Relevance

Proparacaine in combination with pilocarpine would be the best choice for treating dogs with acute glaucoma. Topical administration of NSAID should not be used to treat dogs with acute glaucoma, because they increase intraocular pressure and negate the effects of pilocarpine. (Am J Vet Res 1998;59:482–488)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To analyze and compare contents of the preocular tear films of llamas and cattle.

Animals—40 llamas and 35 cattle.

Procedure—Tear pH was determined by use of a pH meter. Total protein concentration was determined by use of 2 microtiter methods. Tear proteins were separated by use of electrophoresis and molecular weights of bands were calculated. Western blot immunoassay was used to detect IgA, lactoferrin, transferrin, ceruloplasmin, α1-antitrypsin, α1-amylase, and α2-macroglobulin. Enzyme electrophoresis was used to detect proteases.

Results—The pH of llama and cattle tears were 8.05 ± 0.01 and 8.10 ± 0.01, respectively. For results of both methods, total protein concentration of llama tears was significantly greater than that of cattle tears. Molecular weights of tear protein bands were similar within and between the 2 species, although llama tears had a distinct 13.6-kd band that was not detected in cattle. Lactoferrin, IgA, transferrin, ceruloplasmin, α1-antitrypsin, α1-amylase, α2–macroglobulin, and proteases were detected in both species.

Conclusions and Clinical Relevance—Llama tears have significantly greater total protein concentration than cattle tears, whereas pH is similar between species. Because little variation was detected within species for the number and molecular weight of protein bands, pooling of tears for analysis is justified. Results suggest that lactoferrin, ceruloplasmin, transferrin, α1-antitrypsin, α2-macroglobulin, α1-amylase, and IgA are present in the tears of llamas and cattle. (Am J Vet Res 2000;61:1289–1293)

Full access
in American Journal of Veterinary Research