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  • Author or Editor: John J. Lucas x
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Abstract

Objective—To evaluate the cytopathic effects of Tritrichomonas foetus and a purified cysteine protease (ie, CP30) of T foetus on cultured bovine uterine epithelial cells (BUECs) in vitro.

Sample Population—10 reproductive tracts were obtained from late-term bovine fetuses at a commercial abattoir.

Procedure—An in vitro culture system of BUECs was developed to study the cytopathic effects of T foetus and purified CP30 of T foetus on host cells. Cytotoxicity of T foetus or CP30 on exposed BUECs was determined. Fluorescence microscopy and flow cytometry analyses were used to detect apoptosis. A fluorometric assay was used to detect BUEC caspase 3 activation. The CP inhibitor E-64 and a caspase inhibitor were used to inhibit apoptosis.

Results—Cytopathic effects were observed in BUECs treated with parasites or CP30 and were concentration and time dependent. The BUECs underwent apoptosis in the presence of parasites or CP30. The specific CP inhibitor E-64 abolished the induction of apoptosis in BUECs by CP30. The caspase inhibitor reduced the amount of apoptosis in BUECs.

Conclusions and Clinical RelevanceT foetus and its CP30 induce apoptosis in cultured BUECs in vitro. Induction of apoptosis by CP30 is correlated with protease activity. Endometrial cell death as a result of a T foetus infection is likely to be more important in mediating infertility than a direct effect on the conceptus. Provoking an apoptotic reaction in the host may mitigate an inflammatory reaction or immune response and therefore favor survival of the parasite in a chronic infection. (Am J Vet Res 2005;66:1181–1186)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the efficacy of ceftiofur crystalline- free acid (CCFA) administered into the posterior aspect of an ear for treatment of corneal ulceration associated with naturally occurring infectious bovine keratoconjunctivitis (IBK).

Animals—78 beef calves located at Sierra Foothills Field Station (SFS) and 52 calves located at a commercial dairy (CD). All calves were from 3 to 9 months old.

Procedure—At each site, calves were randomly allocated to 1 of 2 treatment groups by use of a block design determined by corneal ulcer size. A single dose of CCFA (6.6 mg of ceftiofur equivalents/kg, SC) was administered into the posterior aspect of a pinna. A second group of calves received a single dose of vehicle (0.03 mL/kg, SC; controls). Corneal ulcers were photographed, and clinical signs were assessed in calves every 3 to 4 days for 21 days.

Results—A positive treatment effect was detected at SFS. Results at the CD were inconclusive because ulcer healing occurred rapidly in control and CCFA-treated calves. At SFS, treatment with CCFA resulted in shorter mean healing times, smaller corneal ulcer surface area measurements, amelioration of ocular discharge and photophobia, and a 50% increase in the percentage of calves healed by day 14. After adjustment for initial corneal ulcer size, treatment with CCFA resulted in a 4-fold increase in the odds of corneal ulcer healing by day 14, compared with controls.

Conclusions and Clinical Relevance—A single dose of CCFA administered into the posterior aspect of a pinna had a positive treatment effect against naturally occurring IBK in calves with corneal ulcerations . (Am J Vet Res 2004;65:1185–1188)

Full access
in American Journal of Veterinary Research