Objective—To determine effects of topical antimicrobial
and antimicrobial-corticosteroid preparations on
the ocular flora of horses.
Procedure—One eye was treated 3 times daily for 2
weeks with one of the following ointments: 1) neomycinbacitracin-
polymyxin B, 2) 0.6% prednisolone-0.3% gentamicin,
3) neomycin-polymyxin B-0.05% dexamethasone,
or 4) treated (artificial tears) control. Contralateral eyes of
treated control eyes served as untreated control eyes.
Corneal and conjunctival specimens for bacterial and fungal
cultures were collected prior to initiation of treatment,
after 1 and 2 weeks of treatment, and 2 weeks after concluding
treatment. Changes in culture growth quantity
scores of bacterial and fungal species were analyzed.
Results—The most common species before treatment
were the following: gram-positive bacteria included
Streptomyces spp (66%) , Staphylococcus spp (46%) ,
Bacillus spp (32%) , and Streptococcus spp (32%); gramnegative
bacteria included Moraxella spp (28%) ,
Escherichia coli (24%) , Acinetobacter spp (18%), and
Enterobacter spp (14%); and fungi included Aspergillus
nidulans (56%) , Cladosporium spp (32%), and
Aspergillus fumigatus (22%). In all groups, the percentage
of positive bacterial culture results, growth quantity
score of gram-positive bacteria, and number of bacterial
species isolated decreased at week 1 and increased at
week 2, whereas growth quantity score of gram-negative
bacteria decreased throughout treatment. Differences
were not significant among groups. Fungal growth quantity
score decreased during treatment in all groups.
Repopulation of bacterial and fungal species occurred.
Conclusions and Clinical Relevance—All interventions
decreased the number of microorganisms.
Repopulation of normal flora occurred during and after
treatment. (Am J Vet Res 2005;66:800–811)
Case Description—A 13-year-old female Miniature Horse was evaluated for progressive unilateral exophthalmia of the left globe of 3 weeks' duration.
Clinical Findings—Results of a physical examination were unremarkable. Ophthalmic examination identified exophthalmus of the left globe with complete resistance to retropulsion and mild blepharoconjunctivitis. Computed tomography revealed a large, space-occupying mass within the left caudal maxillary and left conchofrontal sinuses. The mass extended into the left retrobulbar space and contacted the cribriform plate. Trephination yielded copious amounts of turbid yellow fluid. The diagnosis was a sinonasal cyst.
Treatment and Outcome—Subtotal surgical excision of the cyst via a frontonasal osteoplastic flap was curative, with complete resolution of the exophthalmus. Histologic examination confirmed diagnosis of a sinonasal cyst. There was no evidence of cyst recurrence by 4 months after surgery.
Clinical Relevance—Sinonasal cyst should be a differential diagnosis for retrobulbar disease in horses. Exophthalmia may be the only clinical finding in horses with a sinonasal cyst.
OBJECTIVE To determine the effects of grape seed extract (GSE), lutein, and fish oil containing omega-3 fatty acids on oxidative stress, migration, proliferation, and viability of lens epithelial cells (LECs).
SAMPLE Lens capsules or cultured LECs obtained from canine cadavers.
PROCEDURES An antioxidant reductive capacity assay was used to determine reducing capability of each substance. The LECs were cultured and incubated with various substances, including N-acetyl cysteine (NAC), when appropriate, and dimethyl sulfoxide (DMSO) as positive and vehicle control substances, respectively. A dichlorofluorescein assay was used to evaluate reactive oxygen species (ROS) production, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine cell viability. Ex vivo posterior capsule opacification (PCO) was used to evaluate LEC migration and proliferation.
RESULTS Antioxidant reductive effects of GSE surpassed those of NAC, lutein, and fish oil containing omega-3 fatty acids. The GSE reduced ROS production in LECs, compared with the DMSO vehicle control, whereas lutein was pro-oxidative. All test substances reduced cell viability. Ex vivo PCO was not altered by GSE, was decreased by lutein, and was increased by fish oil containing omega-3 fatty acids, compared with results for the DMSO vehicle control.
CONCLUSIONS AND CLINICAL RELEVANCE Only GSE had significant antioxidant capabilities and reduced ROS production; however, no effect on ex vivo PCO was detected. Fish oil containing omega-3 fatty acids increased ex vivo PCO. No conclusions could be made regarding antioxidant effects of these substances on LECs. These findings suggested that the substances will not decrease PCO.
To compare electroretinographic (ERG) responses obtained in dogs before and after oral administration of gabapentin, trazodone, and a combination of both medications.
12 clinically normal dogs.
A short-protocol ERG with 20 minutes of dark adaption was recorded for all dogs to establish baseline ERG responses. Dogs then received gabapentin (approx 30 mg/kg), trazadone (approx 20 mg/kg or approx 5 mg/kg), or a combination of gabapentin (approx 20 mg/kg) and trazodone (approx 5 mg/kg) orally, and the same ERG protocol was repeated 2 hours later. Dogs were given a washout period of at least 1 week between treatments.
a-Wave amplitudes were significantly (P = 0.018) decreased after administration of the combination of gabapentin and trazodone. b-Wave amplitudes were significantly decreased after administration of the 20-mg/kg dose of trazodone (P = 0.006) and after administration of the combination of gabapentin and trazodone (P = 0.002). Heavier dogs that received higher total doses of trazodone had decreases in a-wave amplitude after administration of the 20-mg/kg dose of trazodone and in b-wave amplitude after administration of the 5-mg/kg dose of trazodone.
High doses of trazodone and the combination of gabapentin and trazodone significantly decreased a-wave and b-wave amplitudes in clinically normal dogs. However, the effects on retinal responses had little clinical importance. Therefore, these medications can be used safely in a clinical setting; however, further studies are needed in dogs with retinal disease.
PROCEDURES Horses were randomly assigned (3/group) to first receive topical treatment of the left eye with 1% atropine or artificial tears solution; the right eye was left untreated. After 24 hours of treatment every 6 hours, 200 nontoxic beads were administered to each horse via nasogastric intubation and treatment frequency was decreased to every 12 hours for 4 more days. Pupillary light reflexes (PLRs), mydriasis, heart rate, fecal bead passage, abdominal girth measurements, auscultable gut sounds, fecal weight, and clinical signs of abdominal pain were monitored. Following a 4-week washout period, horses received the opposite treatment in the left eye and measurements were repeated. Serum atropine concentration (reflecting systemic absorption) was measured with an ELISA at various points after initial atropine administration.
RESULTS No horse had subjective or objective evidence of colic or ileus at any monitoring point. Complete mydriasis of the left eye with absence of the PLR was identified in 5 horses within 6 hours and in all 6 horses within 12 hours after initial atropine administration. One horse had mydriasis with an absent PLR in the untreated eye by day 5 of atropine treatment. At no point was atropine detected in serum samples of any horse.
CONCLUSIONS AND CLINICAL RELEVANCE Topical atropine application at clinically appropriate doses induced no evidence of ileus in healthy horses.
Objective—To evaluate effect of adjunctive treatment with tetracycline analogues on time to complete corneal reepithelialization in dogs with nonhealing (ie, refractory) corneal ulcers.
Design—Randomized controlled clinical trial.
Animals—89 dogs with refractory corneal ulcers.
Procedures—Corneal ulcers were treated via debridement and grid keratotomy. Dogs were assigned to receive 1 of 3 treatment regimens for up to 6 weeks: doxycycline (5 mg/kg [2.27 mg/lb], PO, q 12 h) with topically applied ophthalmic ointment containing neomycin, polymyxin B, and bacitracin (ie, triple antibiotic ointment; q 8 h); cephalexin (22 mg/kg [10 mg/lb], PO, q 12 h) with topically applied oxytetracycline ophthalmic ointment (q 8 h); or a control treatment of cephalexin (22 mg/kg, PO, q 12 h) with topically applied triple antibiotic ointment (q 8 h). Healing was monitored via measurements of the wound with calipers and evaluation of photographs obtained every 2 weeks. Treatment effectiveness was evaluated by wound healing and decreased signs of pain.
Results—The Boxer breed was overrepresented in all groups. At the 2-week time point, wound healing was significantly more common in small-breed dogs, compared with large-breed dogs. Dogs treated with oxytetracycline ophthalmic ointment had a significantly shorter healing time than did dogs receiving the control treatment. Corneal ulcers in dogs that received doxycycline PO healed more rapidly than did ulcers in dogs in the control treatment group; however, this difference was not significant.
Conclusions and Clinical Relevance—Topical tetracycline ophthalmic ointment was a safe, inexpensive, and effective adjunctive treatment for refractory corneal ulcers in dogs.