A genome-wide association study to investigate genetic loci associated with primary glaucoma in American Cocker Spaniels.

OBJECTIVE: To identify genetic associations with primary glaucoma (PG) in American Cocker Spaniels using a genome-wide association study (GWAS). ANIMALS: A nationwide ambidirectional case-control cohort study was performed in American Cocker Spaniels that had an ophthalmic examination performed by a veterinarian. Ninety-four dogs with PG (cases) and 111 dogs without glaucoma (controls) met phenotypic criteria and had a blood sample collected after receiving informed owner consent. PROCEDURES: Genomic DNA was extracted from whole blood samples and genotyped (CanineHD BeadChip, Illumina Inc). A case-control GWAS using a linear mixed model was performed, and 3 significance thresholds were calculated (1) using a Bonferroni correction on all single nucleotide polymorphisms (SNPs) included in the GWAS, (2) using a Bonferroni correction on only the unlinked SNPs from a pruned data set, and (3) using 10,000 random phenotype permutations. RESULTS: Following genotype data quality control, 89 cases and 93 controls were included in the GWAS. We identified an association on canine chromosome (CFA10); however, it did not reach statistical significance. Potential candidate genes within the surrounding linkage disequilibrium interval include coiled-coil domain containing 85A (CCDC85A) and extracellular growth factor containing fibulin extracellular matrix protein 1 (EFEMP1). CLINICAL RELEVANCE: Primary glaucoma in the American Cocker Spaniel is a complex heterogeneous disease that may be influenced by a locus on CFA10. The candidate genes CCDC85A and EFEMP1 within the identified linkage disequilibrium interval have been shown to be involved in human open-angle glaucoma.

Effects of topically applied heterologous serum on reepithelialization rate of superficial chronic corneal epithelial defects in dogs.

OBJECTIVE To assess the effects of topical application of undiluted heterologous serum on time to corneal reepithelialization in dogs with superficial chronic corneal epithelial defects (SCCEDs). DESIGN Multicenter, randomized, double-masked, controlled clinical trial. ANIMALS 41 client-owned dogs. PROCEDURES After collection of baseline clinical and historical data, dogs were randomly assigned to receive topically applied undiluted heterologous serum (n = 22) or isotonic saline (0.9% NaCl) solution (19) along with tobramycin and atropine. Epithelial debridement (at all visits) and grid keratotomy (at visits 2, 3, and 4) of SCCEDs were performed. Ophthalmic examination including fluorescein application was performed once weekly for 4 weeks or until corneal reepithelialization. Clinicians and owners were masked to treatment group. RESULTS No differences in baseline data were detected between treatment groups. No difficulties with medication administration, noncompliance, or adverse reactions were noted. All SCCEDs in both groups healed by 4 weeks after treatment began. Median time to reepithelialization (2 weeks) was not significantly different between serum-treated and placebo-treated eyes. Irrespective of treatment group, median time to reepithelialization was not significantly different for Boxers versus non-Boxer breeds. Direct correlations were detected between time to reepithelialization and vascularization score at study entry, vascularization score at time of reepithelialization, and ulcer area at study entry in both groups. Time to reepithelialization was not correlated with age, sex, or duration of signs in either group. CONCLUSIONS AND CLINICAL RELEVANCE Topical application of undiluted heterologous serum was well tolerated by dogs with SCCEDs but, as an adjunct to standard treatment, did not reduce time to corneal reepithelialization.

Ocular myxoid leiomyosarcoma in a cat.

A case of myxoid leiomyosarcoma likely of iris dilator muscle origin in the enucleated eye of a 6-year-old domestic short haired cat is reported. The poorly demarcated mass expanded the iris, partially filled the globe and extended into the optic nerve. The mass was composed of spindle cells separated by abundant matrix positive for mucopolysaccharides with alcian blue. The neoplastic cells were immunoreactive for smooth muscle actin (SMA), S100 and vimentin, and negative for cytokeratin, Melan-A, glial fibrillary protein (GFAP) and desmin. There was no evidence of recurrence or metastasis 6 months after enucleation.

Successful treatment of head shaking by use of infrared diode laser deflation and coagulation of corpora nigra cysts and behavioral modification in a horse.

CASE DESCRIPTION: A 15-year-old Saddlebred gelding used for competitive pleasure driving had a 1-year history of head shaking while pulling a cart. CLINICAL FINDINGS: The horse had cystic corpora nigra in both eyes and concomitant classic and operant conditioned responses to wearing a bridle with bilateral eye covers (blinkers). TREATMENT AND OUTCOME: Deflation and coagulation of the cysts with an infrared diode laser and behavior modification consisting of desensitization and counter-conditioning were used to successfully restore performance. CLINICAL RELEVANCE: Behavioral changes in horses can result from a combination of physical and psychologic causes. A combination of appropriate medical treatment of physical abnormalities and a behavioral modification plan is necessary to successfully treat behavioral problems in these patients.

Comparison of ophthalmic measurements obtained via high-frequency ultrasound imaging in four species of snakes.

OBJECTIVE: To measure the dimensions of the eyes of living snakes by use of high-frequency ultrasound imaging and correlate those measurements with age, length, and weight. Animals-14 clinically normal snakes. PROCEDURES: Species, age, length, weight, and horizontal spectacle diameter were recorded, and each snake underwent physical and ophthalmic examinations; ultrasonographic examination of both eyes was performed by use of a commercially available ultrasound unit and a 50-MHz transducer. Ultrasonographic measurements included spectacle thickness, subspectacular space depth, corneal thickness, anterior chamber depth, lens thickness, vitreous cavity depth, and globe length. All measurements were made along the visual axis. RESULTS: 2 corn snakes, 5 California king snakes, 1 gopher snake, and 6 ball pythons were examined. There were no significant differences within or between the species with regard to mean spectacle thickness, corneal thickness, or subspectacular space depth. However, mean horizontal spectacle diameter, anterior chamber depth, and axial globe length differed among the 4 species; for each measurement, ball pythons had significantly larger values than California king snakes. CONCLUSIONS AND CLINICAL RELEVANCE: Spectacle thickness, subspectacular space depth, and corneal thickness were similar among the species of snake examined and did not vary significantly with age, length, or weight. Measurements of these dimensions can potentially serve as baseline values to evaluate snakes of these species with a retained spectacle, subspectacular abscess, or subspectacular fluid accumulation. Anterior chamber depth and axial length appeared variable among species, but axial length did not vary with age, length, or weight in the species studied.

Taenia coenurus in the orbit of a chinchilla.

A 4-year old, male intact, captive-bred chinchilla (Chinchilla lanigera) was presented due to progressive exophthalmos of the right eye over a 5-month period. Ophthalmic examination revealed exophthalmos with dorsal displacement of the right globe. Retropulsion was decreased and a fluctuant, subcutaneous mass could be palpated posterior and dorsal to the central aspect of the zygomatic bone. Transdermal ultrasonography revealed a fluid-filled mass consistent with a cyst located within the ventral right orbit. Computed tomography demonstrated dorsal displacement of the globe, lateral displacement of the zygomatic arch, and numerous mineral-dense foci within the lumen of the cyst. The cyst was removed en bloc by ventral transpalpebral orbitotomy. Histopathology revealed a single capsulated cyst with multiple invaginated protoscolices, characterized by a prominent scolex with refractile hooklets, suckers, and abundant calcareous corpuscles consistent with a Taenia coenurus. Exophthalmos resolved with surgical therapy and there was no evidence of recurrence or postoperative complications over a period of 2 years. To the authors' knowledge, this is the first reported case of an orbital cyst of parasitic origin in a chinchilla.

Osteosarcoma of the humeral head associated with osteochondritis dissecans in a dog.

A 6-year-old, male Labrador retriever was presented for lameness of the right forelimb. The lameness occurred 5 years after the dog was surgically treated for osteochondritis dissecans (OCD) of the caudal right humeral head. Radiographs revealed an expansile, osteolytic lesion occupying the entire caudal half of the right humeral head, and biopsy confirmed the diagnosis of osteosarcoma. Forelimb amputation was performed. Histopathology of the lesion and associated articular cartilage revealed neoplastic osteoblasts extensively infiltrating the marrow space adjacent to scar tissue associated with the previous OCD lesion. This is the first report of an epiphyseal osteosarcoma in the area of a previous OCD lesion in a dog.

The use of corticosteroids to treat ocular inflammation.

Corticosteroids are invaluable therapeutic agents for treatment of ocular inflammation in small animal patients. The use of potent anti-inflammatory agents carries with it the risk of some side effects, however. Although some of these may be lessened by topical or subconjunctival administration, these routes are associated with specific ocular side effects about which the practitioner must be aware. With judicious use, corticosteroids remain a mainstay for the prevention and treatment of many painful and potentially blinding ocular diseases.