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in Journal of the American Veterinary Medical Association

Summary

Antibody titer to Ehrlichia risticii was determined, in 2,549 equine serum samples, using an indirect fluorescent antibody assay. During 1986, samples were obtained from the Minnesota State-Federal Equine Infectious Anemia Diagnostic Laboratory, the Minnesota Racing Laboratory, from horses admitted to the University of Minnesota Veterinary Teaching Hospital, and as a result of field investigations of horses with acute diarrhea. Results of the study revealed antibody prevalence of 33, 24, 47, and 25% for the respective groups. There was no statistical association between seropositive status and age, sex, breed, or clinical problem of horses referred to the teaching hospital. There was an increase in the total percentage of seropositive samples over the duration of the sample collection period, suggesting a seasonal exposure pattern, and E risticii was associated with clinical and subclinical infections in horses of Minnesota.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether repetitive sequence-based polymerase chain reaction (rep-PCR) could be used to differentiate Streptococcus equi isolates, to examine S equi isolates from throughout the world, and to determine whether a horse had > 1 subtype of S equi during an outbreak of disease.

Sample Population—An initial group of 32 S equi isolates, 63 S equi isolates from various geographic areas, and 17 S equi isolates obtained during outbreaks of disease.

Procedure—An aliquot of S equi genomic DNA was amplified, using enterobacterial repetitive intergenic consensus primers. Gel electrophoresis was performed on 1.5% agarose gels, and a computed-assisted program was used to compare rep-PCR results.

Results—Use of these primers to analyze 100 ng of S equi genomic DNA resulted in patterns of 6 to 14 bands. The 32 initial isolates were separated into 7 rep- PCR subtypes. There were 30 rep-PCR subtypes found among 29 S equi isolates obtained from Minnesota, Michigan, Canada, and Australia and 34 S equi isolates obtained from Kentucky and other sources. Furthermore, the same clone was identified in several horses during an outbreak of disease. Infected horses on the same farm all had a single clone of S equi.

Conclusion and Clinical Relevance—Analysis of these results suggests that rep-PCR is useful for delineating S equi into rep-PCR subtypes. Results revealed that isolates with the same geographic source or similar date of collection did not always have the same rep-PCR subtype. A single clone of S equi usually predominated during an outbreak of disease. (Am J Vet Res 2000;61:699–705)

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in American Journal of Veterinary Research

Objective

To evaluate the effect of a single dose of recombinant bovine somatotropin (bST) on certain metabolic values, health, and milk production of dairy cows undergoing surgery for left displacement of the abomasum.

Design

Blinded clinical trial.

Animals

413 cows with left displacement of the abomasum.

Procedure

A single 500-mg dose of bST was administered to dairy cows following surgery in field practice conditions for left displacement of the abomasum. A placebo of the same carrier without bST was administered to control cows in this blinded study. Metabolic and production responses in a short-term follow-up period were measured.

Results

Blood glucose concentrations in cows 3 to 5 days after surgery were statistically higher for treated cows than for control cows. A higher proportion of treated cows had improved urine ketone test results than did controls. Significant differences in other metabolic values, health, and milk production were not detected.

Clinical Implications

Treatment of metabolically compromised cows with bST may have some positive effects, but further investigation is needed to confirm therapeutic value. (J Am Vet Med Assoc 1999;214:529–531)

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine whether supplemental IV calcium administration would attenuate or prevent gentamicin-induced acute renal failure, defined as an increase in serum creatinine concentration ≥ 50% above baseline.

Animals

10 healthy pony mares.

Procedure

Pony mares were randomly assigned to receive calcium at a dosage of 20 mg/kg of body weight or saline solution IV, twice daily for 14 days. All pony mares received gentamicin at a dosage of 20 mg/kg IV every 8 hours for 14 days. Gentamicin pharmacokinetic, serum biochemical, and urinalysis data were measured every other day for the 14-day study period. Renal histologic examination was performed, and results were scored at the end of the 14-day period.

Results

4 of 5 mares not receiving calcium supplementation developed acute renal failure. Only 1 of the 5 mares receiving calcium supplementation developed acute renal failure. Over the course of the study, pony mares receiving calcium supplementation had significantly fewer changes in urinalysis variables, and significantly less microscopic renal damage.

Conclusion

Daily IV administration of calcium attenuated gentamicin-induced acute renal failure.

Clinical Relevance

Calcium supplementation may help diminish the risk of acute renal failure associated with aminoglycoside antibiotics. (Am J Vet Res 1998;59:1055–1062)

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in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

Pneumonic pasteurellosis was experimentally induced in calves by inoculation of 5 × 108 Pasteurella haemolytica organisms into the right diaphragmatic lung lobe. Blood and bronchoalveolar lavage fluid samples were obtained prior to inoculation and at postinoculation hour (pih) 2, 4, and 6. Calves developed acute lung injury, characteristic of pneumonic pasteurellosis. Lesions were found only in the right diaphragmatic lobe. By pih 4, significant (P < 0.01) increases were detected in lavage fluid total cell count, neutrophil count, total protein and albumin concentrations, and alkaline phosphatase (alp) and lactic dehydrogenase (ld) activities. Myeloperoxidase and elastase activities did not increase. Neutrophil depletion ameliorated the lung lesions and prevented the increase in lavage fluid cell count, total protein, and albumin concentrations and alp and ld activities. Treatment with the iron chelator, deferoxamine mesylate-hydroxyethyl starch, attenuated the increase in total protein and albumin concentrations and alp and ld activities at pid 4, but not pih 6. Treatment with a neutrophil function inhibitor, pentoxifylline, prevented the increase in lavage fluid neutrophil numbers, but accentuated the increase in total protein and albumin concentrations, and alp, ld, myeloperoxidase, and elastase activities.

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in American Journal of Veterinary Research