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  • Author or Editor: Sheryl G. Krohne x
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Abstract

Objective—To develop a reverse transcriptase-polymerase chain reaction (RT-PCR) assay to detect feline herpesvirus-1 (FHV-1) latency-associated transcripts (LATs) in the corneas and trigeminal ganglia of cats that did not have clinical signs of ocular disease.

Sample Population—Corneas and trigeminal ganglia obtained from 21 cats necropsied at the Indiana Animal Disease Diagnostic Laboratory and 25 cats euthanatized at a humane shelter; none of the cats had a recent history of respiratory tract or ocular disease, and all had normal results for ophthalmic examinations.

Procedure—Both corneas and both trigeminal ganglia were harvested from each cat. An initial PCR assay detected FHV-1 DNA in the corneas and trigeminal ganglia. The RNA was then isolated from samples positive for FHV-1 DNA, and an RT-PCR assay was used to detect LATs.

Results—FHV-1 DNA was detected in 45 of 92 (48.9%) corneas and 38 of 92 (41.3%) trigeminal ganglia. In many samples, the RNA had degraded and RTPCR assay was not possible. Of the samples subjected to RT-PCR assay, none of the 39 corneas but 4 of 16 trigeminal ganglia had positive results when tested for LATs.

Conclusions and Clinical Relevance—Analysis of the results indicated that a high percentage of cats that did not have clinical signs of ocular disease had detectable FHV-1 DNA in their corneas and trigeminal ganglia. This study documents that the RT-PCR assay can successfully identify LATs and may serve as a tool to better understand the biologic characteristics of FHV-1 and its relationship to clinical disease. ( Am J Vet Res 2004;65:314–319)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether oral administration of L-lysine to cats would lessen the severity of conjunctivitis caused by feline herpesvirus (FHV-1).

Animals—8 healthy young adult cats.

Procedure—Cats received oral administration of lysine monohydrochloride (500 mg, q 12 h) or placebo (lactose) beginning 6 hours prior to inoculation of virus. The left conjunctival sac received a 50-µl suspension of FHV-1 grown in cell culture (1.8 X 108 tissue culture infective dose50) on day 1. Cats were evaluated and scores given for clinical signs each day for 21 days. Samples for virus isolation were collected from the eye and throat every third day. Plasma lysine and arginine concentrations were measured prior to the study and on days 3, 14, and 22.

Results—Cats that received lysine had less severe conjunctivitis than cats that received placebo. Virus isolation results did not differ between the groups. Plasma lysine concentration was significantly higher in cats that received lysine, compared with control cats, whereas plasma arginine concentrations did not differ between groups.

Conclusion and Clinical Relevance—Oral administration of 500 mg of lysine to cats was well tolerated and resulted in less severe manifestations of conjunctivitis caused by FHV-1, compared with cats that received placebo. Oral administration of lysine may be helpful in early treatment for FHV-1 infection by lessening the severity of disease. (Am J Vet Res 2002;63:99–103)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether the tears of llamas, sheep, and cattle contain lysozyme and compare lysozyme concentrations in tears among these species.

Animals—40 llamas, 5 sheep, and 36 cattle.

Procedure—Electrophoresis, western blot immunoassay for lysozyme, a spectrophotometric assay to detect tear lysozyme by its ability to lyse a suspension of Micrococcus lysodeiticus, and a microtiter plate colorometric assay were performed.

Results—A 13.6-kd protein band was detected by use of electrophoresis and western blot immunoassay in llama and sheep tears but not cattle tears. Results of spectrophotometric assay suggested that llama and sheep tears had high concentrations of lysozyme, whereas cattle tears had low concentrations. Results of the microtiter plate colorometric assay suggested that llama tears had high concentrations of lysozyme, whereas concentrations in sheep and cattle tears were lower.

Conclusions and Clinical Relevance—Lysozyme concentrations in tears may vary among species and this variability may contribute to differing susceptibilities to ocular diseases such as infectious keratoconjunctivitis. (Am J Vet Res 2000;61:1294–1297)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effect of topical application of a 1% morphine sulfate solution (MSS) on signs of pain and wound healing in dogs with corneal ulcers and examine normal corneas immunohistochemically for the presence of µ and δ opioid receptors.

Animals—12 dogs.

Procedure—A 7-mm superficial corneal ulcer was surgically created in the right eye (OD) of 10 dogs, after which gentamicin solution and 1% MSS (n = 6) or saline solution (4) was administered topically OD 3 times daily. Blepharospasm, tearing, conjunctival hyperemia, aqueous flare, esthesiometer readings, and pupil size were recorded before and 30 minutes after treatment in all dogs. Ulcer size and days to completion of healing were recorded. Corneas from 4 treated and 3 control dogs were evaluated histologically. Normal canine corneas from 2 dogs not used in the study were evaluated immunohistochemically for the presence of µ and δ opioid receptors.

Results—Dogs treated with MSS had significantly less blepharospasm and lower esthesiometer readings than did control dogs. Duration of ulcer healing and findings of histologic evaluation of corneas did not differ between groups. Numerous δ and infrequent µ opioid receptors were identified in the corneal epithelium and anterior stroma of normal corneas.

Conclusions and Clinical Relevance—Topical use of 1% MSS in dogs with corneal ulcers provided analgesia and did not interfere with normal wound healing. Both µ and δ opioid receptors were identified in normal corneas of dogs, although the µ receptors were present only in small numbers. (Am J Vet Res 2003;64:813–818)

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate the in vitro antifungal properties of silver sulfadiazine (SSD) and natamycin against filamentous fungi isolated from eyes of horses with keratomycosis.

Sample Population—Filamentous fungal isolates obtained from eyes of keratomycosis-affected horses.

Procedures—Fungal culture of ocular samples yielded 6 Fusarium spp; 7 Aspergillus spp; and 1 isolate each of Curvularia, Scopulariopsis, Penicillium, and Chrysosporium. For each fungal isolate, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of SSD and natamycin were determined.

Results—For all 17 fungal isolates, SSD MIC distribution ranged from ≤ 1 to > 64 μg/mL; MIC50 and MIC90 (MICs at which 50% and 90% of organisms were inhibited) were 4 and 32 μg/mL, respectively. The SSD MFC distribution for all isolates was ≤ 1 to > 64 μg/mL; MFC50 and MFC90 (MFCs at which 50% and 90% of organisms were killed) were 8 and > 64 μg/mL, respectively. For all fungal isolates, natamycin MIC distribution ranged from 256 to > 1,000 μg/mL; MIC50 and MIC90 were 512 and > 1,000 μg/mL, respectively. The natamycin MFC distribution for all isolates ranged from 512 to > 1,000 μg/mL; MFC50 and MFC90 were each > 1,000 μg/mL.

Conclusions and Clinical Relevance—These in vitro data suggest that SSD is fungicidal against the fungal isolates that were obtained from eyes of horses with keratomycosis and that natamycin is fungicidal against some of the isolates at the drug concentrations evaluated. Silver sulfadiazine may be a therapeutic option for equine keratomycosis.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of eyelid manipulation and manual jugular compression on intraocular pressure (IOP) measurement in clinically normal dogs.

Design—Randomized clinical trial.

Animals—30 dogs (57 eyes) without diseases or medications that affect IOP.

Procedures—An applanation tonometer was used to measure IOP during eyelid manipulation or jugular compression. Six manipulations were used in each eye, including minimal eyelid manipulation, maximal dorsoventral extension of the eyelids, lateral eyelid extension, manual compression of the ipsilateral jugular vein, manual compression of both jugular veins, and lateral eyelid extension with manual compression of both jugular veins. Skull type and position of globe in the orbit were recorded.

Results—The 2 manipulations that caused the greatest significant increase in mean IOP were lateral eyelid extension with compression of both jugular veins (difference from baseline IOP, 17.6 mm Hg; 95% confidence interval [CI], 15.7 to 19.5 mm Hg) and lateral eyelid extension alone (16.5 mm Hg; 95% CI, 14.6 to 18.4 mm Hg). Dorsoventral eyelid extension (6.42 mm Hg; 95% CI, 4.5 to 8.3 mm Hg) and compression of both jugular veins alone (3.0 mm Hg; 95% CI, 1.1 to 5.0 mm Hg) significantly increased mean IOP, compared with baseline. Compression of the ipsilateral jugular vein increased mean IOP (0.3 mm Hg; 95% CI, −1.6 to 2.2 mm Hg) from baseline, but not significantly.

Conclusions and Clinical Relevance—Traction on the eyelids or pressure on both jugular veins can significantly increase IOP values as measured by use of applanation tonometry in clinically normal dogs.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To report values for tear production, central corneal touch threshold (CTT), and intraocular pressure (IOP) in healthy guinea pigs and determine results of aerobic bacterial culture and cytologic examination of conjunctival swab specimens.

Design—Cross-sectional study.

Animals—31 healthy guinea pigs (62 eyes) of various ages and breeds.

Procedures—Tear production was measured by the phenol red thread tear test (PRT) and Schirmer tear test (STT) before and after topical anesthetic application, CTT was measured with an esthesiometer, and IOP was measured by applanation tonometry.

Results—Combining data from all eyes, mean ± SD PRT values before and after topical anesthetic administration were 21.26 ± 4.19 mm/15 s and 22.47 ± 3.31 mm/15 s, respectively, and mean IOP was 18.27 ± 4.55 mm Hg. Median STT values before and after topical anesthetic administration were 3 mm/min (range, 0 to 12 mm/min) and 4 mm/min (range, 0 to 11 mm/min), respectively, and median CTT was 2.0 cm (range, 0.5 to 3.0 cm). Values did not differ between eyes for any test, but significant differences were identified for PRT values between males and females and between values obtained before and after topical anesthetic administration. Common bacterial isolates included Corynebacterium spp, Streptococcus spp, and Staphylococcus spp. Cytologic examination of conjunctival swab specimens revealed mainly basal epithelial cells; lymphocytes were common.

Conclusions and Clinical Relevance—Results provided information on values for PRT, STT, CTT, and IOP in healthy guinea pigs and on expected findings for aerobic bacterial culture and cytologic examination of conjunctival swab specimens.

Restricted access
in Journal of the American Veterinary Medical Association

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 analyze and compare contents of the preocular tear films of llamas and cattle.

Animals—40 llamas and 35 cattle.

Procedure—Tear pH was determined by use of a pH meter. Total protein concentration was determined by use of 2 microtiter methods. Tear proteins were separated by use of electrophoresis and molecular weights of bands were calculated. Western blot immunoassay was used to detect IgA, lactoferrin, transferrin, ceruloplasmin, α1-antitrypsin, α1-amylase, and α2-macroglobulin. Enzyme electrophoresis was used to detect proteases.

Results—The pH of llama and cattle tears were 8.05 ± 0.01 and 8.10 ± 0.01, respectively. For results of both methods, total protein concentration of llama tears was significantly greater than that of cattle tears. Molecular weights of tear protein bands were similar within and between the 2 species, although llama tears had a distinct 13.6-kd band that was not detected in cattle. Lactoferrin, IgA, transferrin, ceruloplasmin, α1-antitrypsin, α1-amylase, α2–macroglobulin, and proteases were detected in both species.

Conclusions and Clinical Relevance—Llama tears have significantly greater total protein concentration than cattle tears, whereas pH is similar between species. Because little variation was detected within species for the number and molecular weight of protein bands, pooling of tears for analysis is justified. Results suggest that lactoferrin, ceruloplasmin, transferrin, α1-antitrypsin, α2-macroglobulin, α1-amylase, and IgA are present in the tears of llamas and cattle. (Am J Vet Res 2000;61:1289–1293)

Full access
in American Journal of Veterinary Research