Frequency of retinal detachments in dogs after prophylactic transpupillary retinopexy.

PURPOSE: To evaluate the frequency of retinal detachments following prophylactic transpupillary retinopexy (PTPRP). METHODS: The medical records of dogs that received a PTPRP between 2014 and 2022 were retrospectively analyzed for age, sex, breed, reason for retinopexy, laser power setting, number of retinal burns, follow-up duration, and outcome. Laser power settings were increased until retinal burns could be visualized and were made 360° in a double row in the peripheral retina. RESULTS: Fifty-seven cases (75 eyes), 28 males and 29 females, had PTPRP performed. The median age was 8 years (4 months-14 years) with Shih tzu (n = 12), Bichon (n = 5), Miniature Poodle (n = 5), and Yorkie (n = 4) being the most common breeds. PTPRP were performed due to severe vitreal degeneration (n = 66), retinal detachment in the contralateral eye (n = 25), capsular tear with escaped lens material during phacoemulsification (n = 6), intracapsular lens extraction (n = 2), and lens luxation during phacoemulsification (n = 3). The median power setting, number of retinal burns, and follow-up time were 300 mW (201-595 mW), 210 burns (35-921 burns), and 473 days (14-1862 days), respectively. Additionally, five patients had a barrier-pexy performed in the contralateral eye, due to partial detachment. Retinal detachment occurred in 3/75 (4.0%) of eyes that received a PTPRP at the final examination. Of the patients with a detachment in the contralateral eye (n = 25), no detachment was noted at the last follow-up examination. Two partial detachments that had barrier-pexies had progressed at the final examination. CONCLUSIONS: These results demonstrate that PTPRP may be beneficial in decreasing the risk of retinal detachment in selected cases.

Clinical description with magnetic resonance appearance of a high-grade undefined optic nerve glioma with intracranial extension.

A 4-year-old mixed-breed dog was presented for hyphema and glaucoma of the right eye. Enucleation of the right globe was carried out, and histopathology examination revealed an optic nerve glioma with incomplete surgical margins. At 8 wk after surgery, the dog had depressed mentation and a diminished pupillary light reflex of the left eye. Magnetic resonance imaging revealed an irregular, heterogeneously T2 hyperintense/T1 isointense mass in the region of the optic chiasm. Compression of the rostral thalamus was present, with effacement of the pituitary gland and involvement of the right orbit. The dog was euthanized 4.5 mo after initial presentation. An undefined glioma of the right optic nerve with extension to the diencephalon was diagnosed on necropsy. Key clinical message: Although rare, intraocular glioma is a differential diagnosis for hyphema, glaucoma, and retinal detachment. Magnetic resonance imaging should be considered in cases of intraocular neoplasia, notably in those with incomplete surgical margins of the optic nerve.

Description clinique avec aspect en résonance magnétique d'un gliome indéfini de haut grade du nerf optique avec extension intracrânienne. Un chien de race croisé âgé de 4 ans a été présenté pour un hyphéma et un glaucome de l'œil droit. Une énucléation du globe droit a été réalisée et l'examen histopathologique a révélé un gliome du nerf optique aux marges chirurgicales incomplètes. Huit semaines après la chirurgie, le chien avait une diminution du processus mental et un réflexe pupillaire à la lumière diminué de l'œil gauche. L'imagerie par résonance magnétique a révélé une masse irrégulière hétérogène hyperintense T2/T1 isointense dans la région du chiasma optique. Une compression du thalamus rostral était présente, avec effacement de l'hypophyse et atteinte de l'orbite droite. Le chien a été euthanasié 4,5 mois après la présentation initiale. Un gliome indéfini du nerf optique droit avec extension au diencéphale a été diagnostiqué à l'autopsie.Message clinique clé:Bien que rare, le gliome intraoculaire est un diagnostic différentiel pour l'hyphéma, le glaucome et le décollement de la rétine. L'imagerie par résonance magnétique doit être envisagée en cas de néoplasie intraoculaire, notamment chez ceux dont les marges chirurgicales du nerf optique sont incomplètes.(Traduit par Dr Serge Messier).

Effects of corneoconjunctival transposition, posterior lamellar keratoplasty and modified deep lamellar endothelial keratoplasty on streak retinoscopy in equine cadaver eyes.

OBJECTIVE: Evaluate the effects of corneoconjunctival transposition (CCT), posterior lamellar keratoplasty (PLK) and modified deep lamellar endothelial keratoplasty (DLEK) on streak retinoscopy in equine cadaver eyes. METHODS: Intraocular pressure (IOP) was maintained at 25 ± 3 mmHg in 35 equine cadaver eyes. Streak retinoscopy was performed prior to (NO VISCO) and following (VISCO) intracameral injection of 1.0 ml of viscoelastic. Following optical coherence tomography (OCT), an axial CCT [n = 11] or PLK [n = 12], or peripheral DLEK [n = 12] was performed. Streak retinoscopy and OCT were repeated postoperatively. RESULTS: Postsurgical net meridional and spherical refraction for CCT [Horizontal (H): 3.4 (95% CI 2.4-4.4) diopters (D), p < .001, Vertical (V): 3.5 (95% CI 2.7-4.4) D, p < .001, Spherical: 3.5 (95% CI 2.6-4.3) D, p < .001] and PLK [H: 3.2 (95% CI 2.2-4.1) D, p < .001, V: 2.8 (95% CI 2.0-3.6) D, p < .001, Spherical: 3.0 (95% CI 2.2-3.8) D, p < .001] were significantly increased from presurgical (VISCO) values. No difference between presurgical (VISCO) and postsurgical values were identified for the DLEK. Postoperative OCT revealed space between anterior and posterior corneal grafts and corneal undulation associated with suture placement. CONCLUSION: Meridional and spherical refraction had a hyperopic shift following CCT and PLK, with a significantly higher value in the vertical meridian for the CCT. Pre- and postoperative refraction was not significantly different for the DLEK. This supports that the DLEK has a lesser effect on immediate postoperative refraction compared with CCT or PLK.

Clinical and pathologic evaluation of chorioretinal lesions in wild owl species.

OBJECTIVE: Investigate histopathology and spectral-domain optical coherence tomography (OCT) imaging of wild owls with chorioretinitis and identify any potential correlation with an infectious etiology. MATERIALS AND METHODS: Ophthalmic examination and retinal OCT imaging were performed on fifteen great horned (Strix varia) and barred (Bubo virginianus) owls (30 eyes) with chorioretinitis and five owls with normal eyes (10 eyes). Testing to investigate the presence of potential infectious diseases included a complete blood count, biochemistry, protein electrophoresis, West Nile virus (WNV) plaque reduction neutralization test, Toxoplasma gondii modified direct agglutination test, WNV RT-PCR, and Avian Influenza RT-PCR. A necropsy was performed on all owls, including ocular histopathology. RESULTS: Fundus lesions included retinal detachment (7/15 owls), depigmented lesions (12/15), pigment clumping (8/15), and retinal tear (4/15). All birds were negative for WNV and Avian Influenza on RT-PCR. Of the owls with chorioretinitis, 3/15 were seropositive for WNV and 7/15 for T. gondii. Optical coherence tomography of 25/30 affected eyes revealed outer retinal lesions (19/25 eyes), retinal detachment (16/25), and retinal tears (3/25). Histopathological examination revealed outer nuclear layer atrophy (19/30 eyes), retinal detachment (18/30), retinal tears (7/30), suprachoroidal hemorrhage (12/30), scleral rupture (3/30), and ossicle fracture (3/30). CONCLUSIONS: Although 20% of birds were seropositive for WNV and 46.6% for T. gondii, histopathologic findings supported that the posterior segment lesions in the study group were likely due to blunt ocular trauma rather than an infectious etiology. The results of OCT imaging and histopathology documented retinal changes most consistent with blunt ocular trauma.

Corneoconjunctival transposition with and without ACell® for deep corneal ulcer repair in 18 dogs.

OBJECTIVE: To document a case series using corneoconjunctival transposition (CCT) surgery with and without bioscaffolding matrix (ACell® ) to repair deep corneal ulcers and perforations in dogs. ANIMALS STUDIED: Eighteen dogs of various breeds that presented with deep or perforating corneal ulcers. PROCEDURES: Corneoconjunctival transposition grafts with or without ACell® were sutured using a simple interrupted 8-0 or 9-0 polyglactin 910 pattern. RESULTS: A total of eighteen dogs (19 eyes) were diagnosed with deep corneal ulcers (n = 7) and perforating corneal ulcers (n = 12). A CCT was performed in all eyes, with ten of them additionally receiving an ACell® graft. The majority of lesions were located axially in 14/19 (81%) eyes. Grafts were harvested from dorsal (n = 8), temporal (n = 5), ventral (n = 4), or nasal (n = 2) quadrants. Brachycephalic breeds (13/18) were over-represented. Keratoconjunctivitis sicca was present in 10/19 eyes (52.6%). Bacterial isolates were cultured from 8/19 eyes. Post-operative therapy included topical antibiotics, plasma, cycloplegics, oral antibiotics, and oral nonsteroidal anti-inflammatory drugs. CCT integration with and without ACell® occurred at a median of 20 days (range 7-38 days) post-operatively with no significant difference between groups. Median follow-up time was 188 days. Short-term post-operative complications included granulation tissue formation (19/19), corneal edema (4/19), graft retraction (4/19), and anterior synechia (1/19). Long-term complications in 14 eyes with follow-up >30 days included superficial corneal pigmentation (6/14) and epithelial inclusion cysts (5/14). Two eyes were nonvisual at last follow-up due to cataract formation. CONCLUSIONS: Corneoconjunctival transposition with ACell® can be utilized for corneal ulcer repair in dogs.

Surgical excision of iridociliary tumors using a postero-anterior cyclo-iridectomy and thermocautery in two dogs.

OBJECTIVE: To report the surgical excision of an iridociliary adenoma and iridal melanocytoma using a postero-anterior cyclo-iridectomy in two dogs. PROCEDURE: A 7 year old neutered male English springer spaniel (case 1) and a 7 year old neutered male Labrador mix (case 2) were presented for evaluation of an intrairidal mass OS. RESULTS: Complete ophthalmic examination revealed a large, dorsonasal, well-demarcated, intrairidal mass OS. A tan to pink intrairidal mass extending into the iridocorneal angle (case 1) and a pigmented intrairidal mass (case 2) were present. B-mode ultrasonography showed a focal, soft tissue, homogenous mass within the uvea adjacent to and contacting the lens. Neither pars plana involvement nor vitreal extension was present. A postero-anterior cyclo-iridectomy was performed through a polyhedral scleral flap. Thermocautery was used to complete the cyclo-iridectomy (case 1) and partial iridectomy (case 2) to excise the mass en bloc. Histopathology revealed a completely excised iridociliary adenoma (case 1) and iris melanocytoma (case 2). The surgery sites healed without complication. Mild uveitis (cases 1 and 2), scant vitreal hemorrhage (case 1), and mild hyphema (case 2) were present three days postoperatively but had resolved ten days postoperatively. The patients remain visual twenty-two months (case 1) and seven months (case 2) postoperatively with a normal intraocular examination other than an iridal defect and mild dorsonasal lens capsular opacities. CONCLUSIONS: The surgical approach described in these cases is utilized in physician-based medicine. This approach and the use of thermocautery provide a viable surgical option for excision of large iridociliary tumors in dogs.

Preliminary report of postoperative complications of phacoemulsification in Pugs: A multicenter retrospective study of 32 cases.

OBJECTIVE: To compare complication rates and visual outcomes following phacoemulsification in Pugs versus dogs of other breeds. ANIMALS STUDIED: Thirty-two pure-bred Pugs (55 eyes) and 32 dogs of other breeds (56 eyes) undergoing phacoemulsification. PROCEDURES: Multi-institutional retrospective medical record review of perioperative factors, postoperative complications, and visual outcomes. The reference population of dogs of varying breeds included surgical cases following each Pug case at the same institutions. Perioperative risk factors and postoperative complication rates were compared between the two populations. RESULTS: Pigmentary keratitis and diabetes mellitus were the most common preoperative comorbidities, found in 75% (P < .001) and 72% (P = .12) of Pugs, respectively. No perioperative factors were significantly associated with postoperative complications in Pugs. Postoperative complication rates were similar between groups; however, the most common complication in Pugs was corneal ulceration (15% of operated eyes), whereas glaucoma was most common in the reference population (13% of operated eyes). Three months postoperatively, vision was preserved in 91% of eyes of Pugs (50/55) and 95% of the reference population (53/56). One year postoperatively, 80% (32/40) of Pug eyes and 82% (28/34) of eyes in the reference population remained sighted. CONCLUSIONS: Comorbidities and complications of cataract surgery in Pugs of this study demonstrate a predisposition for corneal disease. This highlights the importance of preoperative evaluation of factors associated with PK and corneal clarity, and postoperative monitoring for corneal ulceration in this breed.

Modified penetrating keratoplasty with Acell® bioscaffold implant in seven horses with deep full-thickness corneal stromal abscess.

OBJECTIVE: To describe and evaluate a modified penetrating keratoplasty technique utilizing ACell® for management of equine deep stromal or full-thickness corneal stromal abscesses (SA). METHODS: Cases presenting to the University of Georgia Ophthalmology service for surgical management of SA necessitating penetrating keratoplasty (PK) were included in the study population. Surgery entailed the use of an ACell® disk sutured within the deep level of a stepped full-thickness corneal incision with an overlying conjunctival pedicle flap placed in the superficial step incision. Patients were evaluated for success as defined by a comfortable, visual outcome. RESULTS: Surgery was performed in seven horses. Conjunctival flap incorporation and globe retention occurred in all patients. Functional vision was maintained in six of seven eyes (85.7%) at last follow-up examination (mean of 87.6 days [range 41-251 days]). Mean size of ACell® implant was six millimeters (range 4-8 mm). Postoperative complications included moderate to severe anterior uveitis (n = 2), diffuse keratitis (n = 1), incipient cataract formation (n = 3), and anterior and posterior synechiae (n = 1). CONCLUSIONS: This technique is a viable option for treatment of equine SA requiring PK. The use of bioscaffold implant is an alternative to frozen and fresh donor cornea transplantation.

Outcome of conjunctival flap repair for corneal defects with and without an acellular submucosa implant in 73 canine eyes.

OBJECTIVE: To report and compare the success rate of a conjunctival pedicle flap (CPF) alone vs. a CPF with an underlying acellular submucosa implant for the repair of deep or perforating corneal wounds in dogs. PROCEDURES: Records of 69 dogs (73 eyes) receiving a CPF with or without an acellular submucosa implant between 2004 and 2012 were reviewed. Successful outcome was defined as a comfortable eye with vision at the last post-operative evaluation. Age, breed, underlying corneal disease, surgical time, lesion characteristics, topical therapies, and postoperative complications were investigated. RESULTS: Groups consisted of dogs that had a CPF alone (n = 37) and dogs that had a CPF plus an acellular submucosa implant (n = 36). Age, lesion size, surgical time, and time to discontinuation of topical anti-proteolytic medications was not significant between groups. Topical antibiotic use was terminated 13 days sooner (P ≤ 0.01) in dogs with an acellular submucosa implant. The combined success rate of all corneal wounds was 93% with success rate of corneal perforations, descemetoceles, and deep stromal wounds being 89%, 95%, and 100%, respectively. There was no difference in overall success rate between groups. Increasing age was associated with a negative outcome (P ≤ 0.01). Lesion size, presence of a corneal perforation, and concurrent keratoconjunctivitis sicca was not associated with a negative outcome. CONCLUSIONS: A comparable success rate is achieved for deep or perforating corneal wounds stabilized with a CPF alone vs. a CPF plus acellular submucosa. Glaucoma, persistent uveitis, and cataract formation were not reported as post-operative complications in this study population.

Detection of endogenous cortisol in equine tears and blood at rest and after simulated stress.

OBJECTIVE: To determine whether cortisol is present in equine tears at rest and during simulated stress and compare tear cortisol to serum free and total cortisol. MATERIALS AND METHODS: Fourteen healthy adult horses were included. Paired tear total cortisol and serum total and free cortisol concentrations were measured with ELISA, chemiluminescent immunoassay, and ultrafiltration methodology, respectively, in 10 horses at rest once daily for five consecutive days. In an additional four horses, paired tear and serum samples were collected for cortisol measurement before and after adrenocorticotropic hormone (ACTH) stimulation (cosyntropin, 1 µg/kg IV). RESULTS: Cortisol was detectable in equine tears at rest. Following ACTH stimulation, tear cortisol increased significantly from baseline at 60-120 min (P ≤ 0.001). Serum total and free cortisol also increased significantly at 30-180 min after ACTH stimulation (P ≤ 0.001). Both serum and tear cortisol returned to baseline concentrations by 360 min. Changes in tear cortisol were similarly associated with changes in serum total and free cortisol, although high tear cortisol concentrations suggest a portion of tear cortisol may be protein-bound. DISCUSSION: Cortisol is present in equine tears and increases in concert with serum cortisol following ACTH stimulation. Further study is needed to determine whether endogenous cortisol in tears contributes to ocular pathology.

Metagenome-assembled genomes of an acid-tolerant nitrifying bacterial community isolated from a bioreactor used in ammonium scrubbers at animal-rearing facilities.

We report 12 metagenome-assembled genomes (MAGS) of a bioreactor community of acid-tolerant nitrifying bacteria. The MAGS include autotrophs in the Nitrospira genus and heterotrophs in the Xanthomonadales, Ktedonobacterales, Cytophagales, Burkholderiales, and Hyphomicrobiales. These taxonomic and genomic data provide insights into the core community members required for nitrification at low pH.

Concurrent clinical intraocular findings in horses with depigmented punctate chorioretinal foci.

OBJECTIVE: To report concurrent clinical intraocular findings in horses with depigmented punctate chorioretinal foci and to document any correlation with equine recurrent uveitis (ERU). PROCEDURE: Records of 131 horses (241 eyes) examined at the University of Georgia Veterinary Teaching hospital from 2001 to 2010 were reviewed with either clinically normal fundi or depigmented punctate chorioretinal foci in the absence of other fundic pathology. Data collected included patient signalment, concurrent clinical ocular findings and follow-up information. Sex, presence of no other intraocular findings, presence of ERU, presence of cataracts, and presence of vitreal disease were compared between normal and foci groups using chi-squared analysis. Age and length of follow-up time were compared using a student's t-test. RESULTS: Ninety-one horses (167 eyes) with chorioretinal foci and forty horses (74 eyes) with clinically normal ocular fundi were examined. Fifty-eight (64%) horses with chorioretinal foci and 20 (50%) horses with clinically normal fundi had a normal intraocular examination. There was no significant difference in any of the criteria examined between groups. CONCLUSIONS: Horses with depigmented punctate chorioretinal foci, in the absence of other fundic pathology, are not more likely to have intraocular disease or ERU than horses with clinically normal ocular fundi. These findings suggest that depigmented punctate fundic foci in horses are not indicative of or associated with ERU.

Calvarial hyperostosis presenting as unilateral exophthalmos in a female English Springer Spaniel.

A 4-month-old intact female English Springer Spaniel presented to the University of Georgia Veterinary Teaching Hospital for evaluation of unilateral, progressive exophthalmos oculus sinister (OS) of 2 weeks' duration. Complete ophthalmic examination revealed moderate OS exophthalmos and lateral globe deviation. No other abnormalities were noted on physical or ophthalmic examination, ocular ultrasound, complete bloodwork, or thoracic radiography. Skull computed tomography (CT) revealed a large, focal, smoothly irregular, cavitated, expansile bony lesion involving the left caudal maxillary and left frontal bones. Biopsies, obtained through a frontal sinusotomy approach to preserve the left globe integrity, demonstrated normal reactive trabecular bone with locally extensive fibrosis. Calvarial hyperostosis was diagnosed based upon appearance on imaging, lesion unilaterality, absence of mandibular involvement, and histopathology. Six months after initial presentation, skull CT was repeated and marked reduction in the degree of frontal bone thickening was demonstrated with complete resolution of cavitations. There was marked clinical improvement with mild, nonpainful exophthalmos, and lateral globe deviation OS on ophthalmic examination. Eleven months after initial presentation, there was complete resolution of the frontal bone lesion with mild thickening of the left calvarial bones on repeat skull CT. There was no exophthalmos or globe deviation present on clinical ophthalmic examination. The proliferative osteopathic lesion was self-resolving with resolution of the exophthalmos and has not recurred to date. To the authors' knowledge, this is the first report of calvarial hyperostosis in a previously unreported breed presenting as unilateral exophthalmos.

Characterization of cytokines associated with Th17 cells in the eyes of horses with recurrent uveitis.

OBJECTIVE: Equine recurrent uveitis (ERU) is a spontaneous disease that is the most common cause of blindness in horses, affecting up to 15% of the horse population. Th17 cells are a major cell population driving the pathogenesis in several mouse models of autoimmune inflammation, including experimental autoimmune uveitis. The purpose of this study is to investigate the role a Th17 cell-mediated response plays in the pathogenesis of ERU. PROCEDURE: Banked, Davidson's-fixed equine globes histopathologically diagnosed with ERU (n = 7) were compared immunohistochemically with healthy control globes (n = 7). Immunohistochemical staining was performed using a pan-Leptospira antibody and antibodies against IL-6, IL-17, and IL-23. Additionally, immunostaining was performed for T-cell (CD3) and B-cell (CD79α) markers. Specificity of immunoreactivity was confirmed by western blot analysis. RESULTS: Immunohistochemical staining was positive for IL-6, IL-17, and IL-23 within the cytoplasm of nonpigmented ciliary epithelial cells and mononuclear inflammatory cells infiltrating the iris, and ciliary body of ERU horses (n = 7) but negative in controls (n = 7). ERU-affected eyes were CD3 positive (n = 7) and CD79α negative (n = 7). Staining for Leptospira was negative in all ERU and control globes. CONCLUSIONS: Strong immunoreactivity for IL-6, IL-17, and IL-23, in conjunction with the fact that T lymphocytes are the predominating inflammatory cells present in ERU, suggests that IL-17-secreting helper T-cells play a role in the pathogenesis of ERU. These findings suggest that horses with ERU may serve as a naturally occurring animal model for autoimmune uveitis.

Long-term effects of epidural analgesia in labor: a randomized controlled trial comparing high dose with two mobile techniques.

BACKGROUND: Epidural analgesia provides the most effective pain relief in labor, but it is not known if it causes adverse long-term effects. The objective of this study was to assess the long-term effects of two mobile epidural techniques relative to high-dose epidural analgesia in a randomized controlled trial. METHODS: A total of 1,054 nulliparous women were randomized to traditional high-dose epidural, combined spinal epidural, or low-dose infusion. Women in all groups were followed-up at 12 months postpartum by postal questionnaire to assess long-term symptoms. The primary long-term outcome was backache occurring within 3 months of the birth persisting for longer than 6 weeks. Secondary outcomes were frequent headaches and fecal and urinary stress incontinence. RESULTS: No significant differences were found in long-term backache after combined spinal epidural or low-dose infusion relative to high-dose epidural. Significantly less headache occurred in combined spinal epidural analgesia than high-dose epidural (OR: 0.57, 95% CI: 0.36-0.92), but no difference was found for low-dose infusion. Significantly less fecal incontinence (OR: 0.51, 95% CI: 0.30-0.87) and stress incontinence (OR: 0.65, 95% CI: 0.42-1.00) occurred with low-dose infusion. CONCLUSION: Trial evidence showed no long-term disadvantages and possible benefits of low-dose mobile relative to high-dose epidural analgesia.

Comparison of image quality of corneal and retinal optical coherence tomography using sedation and general anesthesia protocols with or without retrobulbar anesthesia in horses.

OBJECTIVE: To compare image quality and acquisition time of corneal and retinal spectral domain optical coherence tomography (SD-OCT) under 3 different sedation-anesthesia conditions in horses. ANIMALS: 6 middle-aged geldings free of ocular disease. PROCEDURES: 1 randomly selected eye of each horse was evaluated via SD-OCT under the following 3 conditions: standing sedation without retrobulbar anesthetic block (RB), standing sedation with RB, and general anesthesia with RB. Five regions of interest were evaluated in the cornea (axial and 12, 3, 6, and 9 o'clock positions) and fundus (optic nerve head). Three diagnostic scans of predetermined quality were obtained per anatomical region. Image acquisition times and total scans per site were recorded. Corneal and retinal SD-OCT image quality was graded on a subjective scale from 0 (nondiagnostic) to 4 (excellent). RESULTS: Mean values for the standing sedation without RB, standing sedation with RB, and general anesthesia conditions were 24, 23, and 17, respectively, for total cornea scan attempts; 23, 19, and 19 for total retina-scan attempts; 14.6, 13.2, and 9.2 minutes for total cornea scan time; 19.1, 9.2, and 13.0 for total retina scan time; 2.0, 2.3, and 2.5 for cornea grade; and 2.7, 2.9, and 2.5 for retina grade. CONCLUSIONS AND CLINICAL RELEVANCE: The RB facilitated globe akinesia and improved the percentage of scans in frame and region of interest accuracy for retinal imaging via OCT in horses. Retrobulbar blocks improved clinical image acquisition while minimizing motion artifact.

Immunohistochemical study of matrix metalloproteinases-2 and -9, macrophage inflammatory protein-2 and tissue inhibitors of matrix metalloproteinases-1 and -2 in normal, purulonecrotic and fungal infected equine corneas.

OBJECTIVE: Determine the effects of matrix metalloproteinases (MMPs)-2, -9, macrophage inflammatory protein-2 (MIP-2), tissue inhibitors of matrix metalloproteinase (TIMP)-1 and -2 by immunohistochemical expression in fungal affected and purulonecrotic corneas. PROCEDURE: Paraffin-embedded equine corneal samples; normal (n = 9), fungal affected (FA; n = 26), and purulonecrotic without fungi (PN; n = 41) were evaluated immunohistochemically for MMP-2, -9, MIP-2, TIMP-1 and -2. The number of immunoreactive inflammatory cells was counted and statistics analyzed. Western blot was performed to detect MMP-2, MMP-9, TIMP-1 and TIMP-2 proteins. RESULTS: Matrix metalloproteinases-2, -9, MIP-2, TIMP-1 and -2 immunoreactivity was identified in corneal epithelium of normal corneas, and in corneal epithelium, inflammatory cells, keratocytes, and vascular endothelial cells of both FA and PN samples. Inflammatory cell immunoreactivity was significantly higher in FA and PN samples than in the normal corneas. There was positive correlation between MMP-2 and MIP-2, MMP-9 and MIP-2, and MMP-9 and TIMP-1 in inflammatory cell immunoreactivity in FA samples. There was positive correlation between MMP-9 and MIP-2, MMP-9 and TIMP-2, MIP-2 and TIMP-1, and MIP-2 and TIMP-2 in inflammatory cell immunoreactivity in PN samples. Western blot confirmed the presence of all four proteins in equine corneal samples. CONCLUSION: Increased immunoreactivity of MMP-2 and -9 in FA and PN samples is indirectly related to MIP-2 through its role in neutrophil chemo-attraction. Tissue inhibitors of matrix metalloproteinase-1 and TIMP-2 are up-regulated in equine purulonecrotic and fungal keratitis secondary to MMP-2 and MMP-9 expression. The correlation between MMPs -2 and -9, MIP-2, TIMPs -1 and -2 suggests that these proteins play a specific role in the pathogenesis of equine fungal keratitis.

Adaptations of subpalpebral lavage systems used for llamas (Lama glama) and a harbor seal (Phoca vitulina).

Subpalpebral lavage systems (SPLSs) were adapted for use in zoo llamas (Lama glama) and a wild harbor seal (Phoca vitulina) during therapy for severe ulcerative keratitis or corneal perforation. One llama presented with a melting corneal ulcer caused by Pseudomonas aeruginosa, which necessitated frequent application of a topical ophthalmic antibiotic. The lavage system was used routinely during the day and was connected to a balloon infusion system at night to allow for continuous medication administration. The ulcer healed soon after therapy was extended to include overnight treatment with the infusion system. A SPLS system was also combined with a balloon infusor during postoperative treatment of a second llama that had sustained a corneal perforation. Both llamas tolerated the infusor/lavage systems well and regained vision. One llama had minor conjunctival irritation from the SPLS that resolved quickly without treatment. Bilateral SPLS were placed in a wild harbor seal for treatment of severe ulcerative keratitis associated with Candida albicans infection. The seal tolerated the lavage systems well throughout 14 wk of their use in an aquatic environment with other seals. Partial detachment of the lavage systems from the skin of the seal occurred a few times during treatment and was easily corrected. Severe keratitis resolved with administration of antimicrobials through the lavage systems, and the seal was returned to the wild. The use of SPLSs alone or in ombination with balloon infusion systems warrants consideration for exotic, wild, and aquatic animals that cannot tolerate repetitive manual applications of topical ophthalmic medication.

In vitro efficacy of a buffered chelating solution as an antimicrobial potentiator for antifungal drugs against fungal pathogens obtained from horses with mycotic keratitis.

OBJECTIVE: To determine whether a novel third-generation chelating agent (8 mM disodium EDTA dehydrate and 20 mM 2-amino-2-hydroxymethyl-1, 3-propanediol) would act as an antimicrobial potentiator to enhance in vitro activity of antifungal medications against fungal isolates obtained from horses with mycotic keratitis. SAMPLE POPULATION: Fungal isolates (3 Aspergillus isolates, 5 Fusarium isolates, 1 Penicillium isolate, 1 Cladosporium isolate, and 1 Curvularia isolate) obtained from horses with mycotic keratitis and 2 quality-control strains obtained from the American Type Culture Collection (ATCC; Candida albicans ATCC 90028 and Paecilomyces variotii ATCC 36257). PROCEDURE: Minimum inhibitory concentrations (MICs) against fungal isolates for 4 antifungal drugs (miconazole, ketoconazole, itraconazole, and natamycin) were compared with MICs against fungal isolates for the combinations of each of the 4 antifungal drugs and the chelating agent. The Clinical and Laboratory Standards Institute microdilution assay method was performed by use of reference-grade antifungal powders against the fungal isolates and quality-control strains of fungi. RESULTS: Values for the MIC at which the antifungal drugs decreased the growth of an organism by 50% (MIC50) and 90% (MIC90) were decreased for the control strains and ophthalmic fungal isolates by 50% to 100% when the drugs were used in combination with the chelating agent at a concentration of up to 540 microg/mL. CONCLUSIONS AND CLINICAL RELEVANCE: The chelating agent increased in vitro activity of antifungal drugs against common fungal pathogens isolated from eyes of horses with mycotic keratitis.

Effects of human recombinant alpha-2b interferon and feline recombinant omega interferon on in vitro replication of feline herpesvirus-1.

OBJECTIVE: To evaluate the effects of recombinant human interferon alpha-2b (rHuIFN-alpha2b) and recombinant feline interferon omega (rFeIFN-omega) on in vitro replication of feline herpesvirus (FHV)-1. SAMPLE POPULATION: Cultures of Crandell-Rees feline kidney (CRFK) cells. PROCEDURES: CRFK cells were treated with rFeIFN-omega or rHuIFN-alpha2b at concentrations ranging from 100 to 500,000 U/mL. Cultures were then inoculated with FHV-1. Constant concentrations of interferon products were maintained throughout the study. Reductions in the number and size of plaques were used as indicators of antiviral activity. Six plaque reduction assays were performed in duplicate. A 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide assay was used to detect cytotoxic effects of interferon. A 1-way ANOVA and Dunnett test were used to determine significant differences. RESULTS: Treatment with rFeIFN-omega at various concentrations resulted in significant reductions in the number of plaques (100,000 U/mL, 54.7%; and 500,000 U/mL, 59.8%) and in plaque size (100,000 U/mL, 47.5%; 250,000 U/mL, 81.0%; and 500,000 U/mL; 70.5%). Treatment with various concentrations of rHuIFN-alpha2b resulted in a significant reduction in plaque size (100,000 U/mL, 56.0%; 250,000 U/mL, 75.7%; and 500,000 U/mL, 69.0%). None of the tested concentrations of interferon caused significant cellular toxicosis. CONCLUSIONS AND CLINICAL RELEVANCE: At some of the higher concentrations, the antiviral effect of rFeIFN-omega was greater than the antiviral effect of rHuIFN-alpha2b. Reduction in plaque size appeared to be a good indicator of the antiviral activity of interferon against FHV-1.