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Abstract

OBJECTIVE To evaluate the effects of topical ophthalmic application of 0.5% proparacaine hydrochloride solution (PHCL; containing 0.01% benzalkonium chloride as preservative) on aerobic bacterial culture results for naturally occurring infected corneal ulcers in dogs.

DESIGN Clinical trial.

ANIMALS 25 client-owned dogs with infected corneal ulcers (24 unilaterally affected and 1 bilaterally affected; only 1 eye included/dog) examined between June 2008 and May 2011.

PROCEDURES Swab samples for aerobic bacterial culture were collected from the periphery of each corneal ulcer before and approximately 1 minute after topical ophthalmic application of 1 drop of PHCL. Numbers of aerobic bacterial species isolated from affected eyes were compared between sample collection points and between other variables (ie, side [left or right] of affected eye, prior treatments, and patient age, sex, and neuter status).

RESULTS There was no significant difference between numbers of aerobic bacterial species isolated per eye or overall aerobic bacterial culture results (positive or negative) before versus after PHCL application. Similarly, prior treatment had no significant effect on aerobic bacterial culture results for samples collected at either point. The most commonly isolated bacteria before and after PHCL application were Staphylococcus spp (40% and 48%, respectively), followed by Streptococcus spp (23% and 22%, respectively).

CONCLUSIONS AND CLINICAL RELEVANCE Topical ophthalmic application of PHCL did not significantly affect aerobic bacterial culture results for naturally occurring infected corneal ulcers in dogs as assessed in this study. Therefore, topical ophthalmic PHCL application could be useful in clinical settings prior to sample collection to relieve patient discomfort and to aid in sample acquisition without compromising aerobic bacterial culture results.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Case Description—A 9-year-old castrated male Bichon Frise was evaluated because of a 3-week history of a nonhealing corneal ulcer and corneal pigmentation of the left eye.

Clinical Findings—Ophthalmic examination of the left eye revealed conjunctival hyperemia, corneal neovascularization, corneal edema, corneal ulceration, and central corneal pigmentation. Intraocular structures of the left eye could not be visually examined because of the diffuse nature of the corneal lesions. The right eye had anterior cortical incipient cataracts, nuclear sclerosis, and an inactive chorioretinal scar.

Treatment and Outcome—Superficial lamellar keratectomy of the left eye was performed for both therapeutic and diagnostic purposes. Histologic evaluation of corneal biopsy specimens revealed dematiaceous fungal keratitis of the left eye, and topical administration of voriconazole was used to successfully resolve the keratitis. Seven months after diagnosis of dematiaceous fungal keratitis, the dog had no clinical signs or history of recurrence of the keratitis.

Clinical Relevance—Dematiaceous fungal keratitis should be considered as a possible cause of nonhealing corneal ulceration with heavy pigment deposition in dogs. Results suggested that lamellar keratectomy along with topical administration of voriconazole can be used successfully to treat dematiaceous fungal keratitis in dogs.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine the effect of oral administration of robenacoxib on inhibition of anterior chamber paracentesis (ACP)-induced breakdown of the blood-aqueous barrier (BAB) and assess whether robenacoxib can cross an intact BAB in healthy cats.

ANIMALS 12 healthy adult domestic shorthair cats.

PROCEDURES Cats received robenacoxib (6-mg tablet in a treat, PO; n = 6) or a control treatment (treat without any drug, PO; 6) once daily for 3 days, beginning 1 day before ACP. One eye of each cat served as an untreated control, whereas the other underwent ACP, during which a 30-gauge needle was used to aspirate 100 μL of aqueous humor for determination of robenacoxib concentration. Both eyes of each cat underwent anterior chamber fluorophotometry at 0 (immediately before), 6, 24, and 48 hours after ACP. Fluorescein concentration and percentage fluorescein increase were used to assess extent of ACP-induced BAB breakdown and compared between cats that did and did not receive robenacoxib.

RESULTS Extent of BAB breakdown induced by ACP did not differ significantly between cats that did and did not receive robenacoxib. Low concentrations of robenacoxib were detected in the aqueous humor (mean, 5.32 ng/mL; range, 0.9 to 16 ng/mL) for 5 of the 6 cats that received the drug.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that oral administration of robenacoxib did not significantly decrease extent of BAB breakdown in healthy cats. Detection of low robenacoxib concentrations in the aqueous humor for most treated cats indicated that the drug can cross an intact BAB.

Full access
in American Journal of Veterinary Research

Abstract

Objectives—To determine whether aqueous humor flare, measured by use of laser flaremetry, was proportional to aqueous humor protein concentration and to use laser flaremetry to evaluate disruption of the blood-aqueous barrier (BAB) in cats.

Animals—30 healthy adult cats.

Procedure—Laser flaremetry values for all eyes were compared with aqueous humor protein concentrations determined by use of a Coomassie blue microprotein assay. Laser flaremetry was then performed on both eyes before (0 hours) and 4, 8, and 26 hours after initiation of topical application of 2% pilocarpine (q 8 h) to 1 eye of 9 cats or paracentesis of the anterior chamber of 1 eye of 8 cats. Intraocular pressure and pupil size were also determined. Aqueous humor protein concentration was extrapolated from flare values by use of linear regression.

Results—There was a linear relationship between flare values and aqueous humor protein concentrations. Topical application of 2% pilocarpine and paracentesis of the anterior chamber caused a breakdown of the BAB that was detected by use of laser flaremetry. The highest mean flare readings after application of pilocarpine or paracentesis were 24.4 and 132.8 pc/ms, respectively, which corresponded to aqueous humor protein concentrations of 85.5 and 434.9 mg/dl, respectively.

Conclusions and Clinical Relevance—Paracentesis of the anterior chamber resulted in a more severe breakdown of the BAB in cats than topical application of 2% pilocarpine. Laser flaremetry may be a useful clinical method to detect increases in aqueous flare and, hence, disruptions of the BAB in cats. (Am J Vet Res 2002;63:750–756)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To quantify plasma concentrations of prednisolone and dexamethasone (peripheral and jugular) and cortisol following topical ophthalmic application of 1% prednisolone acetate and 0.1% dexamethasone to healthy adult dogs.

ANIMALS

12 purpose-bred Beagles.

PROCEDURES

Dogs received 1 drop of 1% prednisolone acetate (n = 6) or neomycin polymyxin B dexamethasone (ie, 0.1% dexamethasone; 6) ophthalmic suspension in both eyes every 6 hours for 14 days. Blood samples (peripheral and jugular) were collected on days 0, 1, 7, and 14 and analyzed for plasma prednisolone and dexamethasone concentrations. Plasma cortisol concentrations were measured at the beginning of the study and following topical drug administration.

RESULTS

Both drugs demonstrated systemic absorption. Prednisolone was detected on days 1, 7, and 14 (median plasma concentration, 24.80 ng/mL; range, 6.20 to 74.00 ng/mL), and dexamethasone was detected on days 1, 7, and 14 (2.30 ng/mL; 0 to 17.70 ng/mL). Neither prednisolone nor dexamethasone were detected in plasma samples on day 0 (baseline). Sampling from the jugular vein resulted in higher plasma drug concentrations than from a peripheral vein when samples from each day were combined. Plasma cortisol concentrations were significantly lower than baseline following 14 days of treatment with topical prednisolone acetate and dexamethasone.

CLINICAL RELEVANCE

Prednisolone and dexamethasone are detected in the plasma of healthy dogs following topical ophthalmic administration 4 times/d with prednisolone concentrations being close to a physiologic dose of orally administered prednisolone. Additional research is needed to evaluate the systemic absorption of these medications in dogs with ocular inflammation.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To assess inhibitory effects of orally administered anti-inflammatory medications on paracentesis-induced intraocular inflammation in clinically normal cats.

Animals—30 clinically normal domestic shorthair cats.

Procedures—Cats were randomly assigned to a control group and 4 treatment groups. Cats in the treatment groups received an anti-inflammatory medication orally once daily at 7 am (acetylsalicylic acid [40.5 mg/cat], meloxicam [0.1 mg/kg], prednisone [5 mg/cat], or prednisolone [5 mg/cat]) for 5 days beginning 2 days before paracentesis-induced breakdown of the blood-aqueous barrier (BAB) and continuing until 2 days after paracentesis. Paracentesis of the anterior chamber was performed in 1 randomly selected eye of each cat. Fluorophotometry was performed in both eyes of each cat immediately before (time 0) and 6, 24, and 48 hours after paracentesis.

Results—At 24 and 48 hours after paracentesis, fluorescein concentration in the eye subjected to paracentesis in the cats receiving prednisolone was decreased, compared with that in the control cats. At 48 hours, a decrease in the fluorescein concentration was also apparent in the eye subjected to paracentesis in the cats receiving meloxicam, compared with that in the control cats. There was no evidence of treatment effects for acetylsalicylic acid or prednisone. There was no evidence of treatment effects in eyes not subjected to paracentesis.

Conclusions and Clinical Relevance—Orally administered prednisolone and meloxicam significantly decreased intraocular inflammation in clinically normal cats with paracentesis-induced BAB breakdown. Oral administration of prednisolone or meloxicam may be an effective treatment for cats with uveitis.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare efficacy and duration of effect on corneal sensitivity of 0.5% proparacaine hydrochloride, 0.5% bupivacaine hydrochloride, 2% lidocaine hydrochloride, and 2% mepivacaine hydrochloride solutions following ocular administration in clinically normal horses.

Animals—68 clinically normal horses.

Procedures—60 horses were assigned to receive 1 anesthetic agent in 1 eye. For each of another 8 horses, 1 eye was treated with each of the anesthetic agents in random order with a 1-week washout period between treatments. Corneal sensitivity was assessed via corneal touch threshold (CTT) measurements obtained with a Cochet-Bonnet aesthesiometer before and at 1 minute, at 5-minute intervals from 5 to 60 minutes, and at 10-minute intervals from 60 to 90 minutes after application of 0.2 mL of anesthetic agent. General linear mixed models were fitted to the CTT data from each of the 2 experimental groups to assess the effects of the anesthetic agents over time, accounting for repeated observations within individual horses.

Results—Corneal sensitivity decreased immediately following topical application of each anesthetic agent; effects persisted for 35 minutes for proparacaine and mepivacaine treatments, 45 minutes for lidocaine treatment, and 60 minutes for bupivacaine treatment. Maximal CTT reduction was achieved following application of bupivacaine or proparacaine solution, whereas mepivacaine solution was least effective.

Conclusions and Clinical Relevance—Ocular application of each evaluated anesthetic agent reduced corneal sensitivity in horses; although 0.5% proparacaine or 2% lidocaine solution appeared to induce adequate short-duration corneal anesthesia, use of 0.5% bupivacaine solution may be more appropriate for procedures requiring longer periods of corneal anesthesia.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate and compare regulation of diabetes mellitus (DM) in dogs with cataracts and well-controlled DM that received an ophthalmic preparation of prednisolone acetate versus diclofenac sodium.

ANIMALS

22 client-owned dogs with cataracts and well-controlled DM.

PROCEDURES

A prospective, randomized, double-masked, experimental study was conducted. On days 0 and 32, serum fructosamine concentrations (SFCs), clinical scores, and body weights were determined. Dogs were assigned to receive a topically administered ophthalmic preparation of either prednisolone acetate 1% or diclofenac sodium 0.1% in each eye 4 times daily for 28 days. Data analysis was conducted with generalized linear mixed models.

RESULTS

Findings indicated no meaningful differences in SFCs, clinical scores, or body weights between the treatment groups on days 0 or 32. Clinical score on day 0 was positively associated with SFC, as indicated by the corresponding rate of change such that each 1 -unit increase in clinical score was associated with an approximately 45.6 ± 9.4 μmol/L increase in SFC. In addition, the least squares mean ± SEM SFC was higher in spayed females (539.20 ± 19.23 μmol/L; n = 12) than in castrated males (458.83 ± 23.70 μmol/L; 8) but did not substantially differ between sexually intact males (446.27 ± 49.72 μmol/L; 2) and spayed females or castrated males regardless of the treatment group assigned.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings indicated no evidence for any differential effect on DM regulation (assessed on the basis of SFCs, clinical scores, and body weights) in dogs treated topically with an ophthalmic preparation of prednisolone versus an ophthalmic preparation of diclofenac. Additional research investigating plasma concentrations of topically applied ophthalmic glucocorticoid medications is warranted. (Am J Vet Res 2019;80:1129-1135)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To investigate long-term outcomes and owner-perceived quality of life associated with sudden acquired retinal degeneration syndrome (SARDS) in dogs.

Design—Survey study.

Animals—100 dogs with SARDS examined at 5 academic veterinary institutions from 2005 to 2010.

Procedures—The diagnosis was based on documented acute vision loss, normal results of ophthalmic examinations, and evaluation of extinguished bright-flash electroretinograms. Primary owners of affected dogs completed a questionnaire addressing outcome measures including vision, systemic signs, and perceived quality of life for their dogs.

Results—Age at diagnosis was significantly correlated with positive outcome measures; dogs in which SARDS was diagnosed at a younger age were more likely to have alleged partial vision and higher owner-perceived quality of life. Polyphagia was the only associated systemic sign found to increase in severity over time. Medical treatment was attempted in 22% of dogs; visual improvement was not detected in any. Thirty-seven percent of respondents reported an improved relationship with their dog after diagnosis, and 95% indicated they would discourage euthanasia of dogs with SARDS.

Conclusions and Clinical Relevance—Blindness and concurrent systemic signs associated with SARDS appeared to persist indefinitely, but only polyphagia increased in severity over time. Most owners believed their pets had good quality of life and would discourage euthanasia of dogs with SARDS.

Full access
in Journal of the American Veterinary Medical Association