Objective—To determine whether a novel third-generation chelating agent (8mM disodium EDTA dehydrate and 20mM 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 μg/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.
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.
6 middle-aged geldings free of ocular disease.
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).
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.
Objective—To evaluate the effects of recombinant human interferon α-2b (rHuIFN-α2b) and recombinant feline interferon ω (rFeIFN-ω) 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-ω or rHuIFN-α2b 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-ω 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-α2b 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-ω was greater than the antiviral effect of rHuIFN-α2b. Reduction in plaque size appeared to be a good indicator of the antiviral activity of interferon against FHV-1.
Objective—To determine the effects of treatment
with and without adjuvant radiation therapy on recurrence
of ocular and adnexal squamous cell carcinoma
(SCC) at specific anatomic locations in horses.
Procedures—Medical records of horses with histologically
confirmed ocular and adnexal SCC evaluated
from 1985 to 2002 were reviewed. Sex, breed, age,
type of treatment, location, and recurrence of SCC
were recorded. Two treatment groups determined by
recurrence of SCCs treated with and without adjuvant
radiation therapy were established.
Results—The anatomic site with the highest recurrence
rate was the limbus (junction of the cornea and
sclera) or bulbar conjunctiva (47.7%), independent of
treatment group. There was a significant difference in
recurrence rates of ocular and adnexal SCCs between
the 2 treatment groups, independent of anatomic location.
Recurrence rates of SCCs treated with and without
adjuvant radiation therapy were 11.9% and 44.1%,
respectively. Recurrence rates for SCCs of the eyelid,
limbus or bulbar conjunctiva, and cornea treated with
adjuvant radiation therapy were significantly different
from those for SCCs treated without adjuvant radiation
therapy. The most frequently represented anatomic
site for ocular and adnexal SCCs was the eyelid
(28.7%). Coat color, breed, and the interaction of age
and breed had a significant effect on tumor recurrence
regardless of treatment type and anatomic location.
Conclusions and Clinical Relevance—Results indicated
that ocular and adnexal SCCs treated with adjuvant
radiation therapy had a significantly lower recurrence
rate, compared with SCCs treated without adjuvant
radiation therapy, independent of anatomic location.
(J Am Vet Med Assoc 2004;225:1733–1738)
Objective—To determine whether amlodipine besylate
decreases systemic arterial blood pressure (BP)
and reduces the prevalence of complications in cats
with induced hypertensive renal insufficiency.
Animals—20 cats with partial nephrectomy.
Procedure—Following reduction in renal mass, 10
cats were administered 0.25 mg of amlodipine/kg,
PO, q 24 h (group A). Ten cats served as a control
group (group C). Systolic BP (SBP), diastolic BP (DBP),
and mean BP (MBP), physical activity, and pulse rate
were measured continuously for 36 days by use of
Results—Compared with values for clinically normal
cats, SBP, DBP, and MBP were significantly increased
in cats of group C. Cats in group A had significant
reductions in SBP, DBP, and MBP, compared with values
for cats in group C. Albuminuria but not urine protein-
to-creatinine ratio was significantly correlated
( R2 = 0.317) with SBP in hypertensive cats.
Prevalence of ocular lesions attributable to systemic
hypertension in group C (7 cats) was greater than that
observed in group A (2). Two cats in group C were
euthanatized on day 16 because of nuerologic complications
attributed to systemic hypertension. One normotensive
cat in group A was euthanatized because
of purulent enteritis of unknown cause on day 27.
Conclusion and Clinical Relevance—Amlodipine
had an antihypertensive effect in cats with coexistent
systemic hypertension and renal insufficiency. Its use
may improve the prognosis for cats with systemic
hypertension by decreasing the risk of ocular injury or
neurologic complications induced by high BP. (Am J
Vet Res 2002;63:833–839)