Myocilin protein levels in the aqueous humor of the glaucomas in selected canine breeds.

OBJECTIVE: To compare aqueous humor myocilin protein levels in dogs with the primary glaucomas to those with the secondary glaucomas, primary cataracts, and diabetic cataracts. MATERIALS AND METHODS: Four groups were selected, based on diagnosis by the attending veterinary ophthalmologists and included: primary glaucoma (primary open-angle glaucoma (POAG) and primary closed angle glaucoma (PCAG); n = 155); secondary glaucoma (n = 94); primary (presumed inherited) cataract (n = 142), and diabetic cataract (n = 83). A total of 474 samples (187 males, 263 females, 24 unreported) with average ages of 117 months for the males and 101 months for the females were analyzed. Myocilin protein was measured using the Coomassie staining and Western blot methods relative to a myocilin control. RESULTS: Differences were seen between nonglaucomatous (cataractous) and glaucomatous dogs with myocilin levels in glaucomatous eyes being many times higher than those in the cataractous dogs. Primary glaucomatous dogs were found to have an aqueous humor myocilin protein level of 17.30 +/- 1.03 units. Secondary glaucomas had the highest level of myocilin in the aqueous humor with 19.27 +/- 1.41 units. Diabetic cataractous dogs had the lowest levels of myocilin reported with 6.60 +/- 0.88 (mean +/- SEM) units. Normal (cataractous) dogs had a myocilin level in the aqueous humor of 8.05 +/- 0.86 units. CONCLUSION: Aqueous humor protein levels were elevated, relative to the myocilin control, in both the primary and secondary glaucoma groups compared to the cataract and diabetic cataract groups. Like in the Beagle POAG, aqueous humor myocilin protein levels are increased. Further studies are indicated to investigate the exact role of the aqueous humor myocilin protein in the genesis in increased IOP in these primary glaucomatous breeds.

Golden Retriever uveitis: 75 cases (1994-1999).

OBJECTIVE: To document the presenting ocular signs and the clinical course of Golden Retriever dogs with a progressive anterior uveitis, often associated with the histologic presence of iridociliary cysts. Animals studied Seventy-five Golden Retriever dogs (142 affected eyes) referred to a private practice referral ophthalmology clinic between 1994 and 1999. Procedures Complete ophthalmic evaluation with slit-lamp biomicroscopy, indirect ophthalmoscopy, applanation tonometry, and gonioscopy. Hematology, serum biochemical evaluations, and serologic titers for endemic infectious agents were also used in selected cases. RESULTS: The age range of affected dogs was 4.5-14.5 years, with a mean age of 8.6 +/- 2.1 years. The majority of the dogs (n = 66) were affected in both eyes at first presentation. The sex distribution included 4 intact males, 32 neutered males, and 39 spayed females. Hematology, serum biochemical evaluations, and serologic titers for endemic infectious agents failed to demonstrate any underlying disorder. The ophthalmic hallmark of this syndrome was the appearance of pigment on the anterior lens capsule, often in a radial orientation. This capsular pigment was seen both with and without associated uveal cysts. Although single to multiple iridociliary cysts were noted clinically in only 13.3% of the cases, cysts were common on histopathology of advanced glaucomatous, blind eyes. Fibrin was observed in the anterior chamber of 37% of the cases, and often was a precursor for glaucoma. Cataract formation (37%) and glaucoma (46%) were frequent sequelae to the uveitis. Posterior synechiae formation occurred in 50% of the cases. Histopathologic analysis of four enucleated eyes and the eviscerated specimens from 14 glaucomatous eyes demonstrated thin-walled iridociliary epithelial cysts in 3/4 and 12/14 cases, respectively. Microscopically, little to no uveal inflammatory infiltration was commonly noted. Conclusion The overall prognosis for this progressive uveitis in Golden Retriever dogs is guarded, with 46% of the eyes becoming blind due to glaucoma. Iridociliary cysts in Golden Retriever dogs may lead to the development of glaucoma in this breed.

Anatomic and radiographic study of the lacrimal apparatus of llamas.

The anatomy of the nasolacrimal duct of llamas was examined grossly and radiographically in 2 llamas. Dacryocystorhinography was performed on cadaver heads, using a radiographic aqueous contrast agent. Anatomic casts of the nasolacrimal apparatus were obtained by cannulation of the duct and use of polyurethane cast material. Dacryocystorhinography accurately revealed the nasolacrimal apparatus and compared favorably with gross dissections and polyurethane casts.