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  • Author or Editor: Malcolm C. Roberts x
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Objective—To determine an infusion rate of butorphanol tartrate in horses that would maintain therapeutic plasma drug concentrations while minimizing development of adverse behavioral and gastrointestinal tract effects.

Animals—10 healthy adult horses.

Procedure—Plasma butorphanol concentrations were determined by use of high-performance liquid chromatography following administration of butorphanol by single IV injection (0.1 to 0.13 mg/kg of body weight) or continuous IV infusion (loading dose, 17.8 µg/kg; infusion dosage, 23.7 µg/kg/h for 24 hours). Pharmacokinetic variables were calculated, and changes in physical examination data, gastrointestinal tract transit time, and behavior were determined over time.

Results—A single IV injection of butorphanol was associated with adverse behavioral and gastrointestinal tract effects including ataxia, decreased borborygmi, and decreased defecation. Elimination half-life of butorphanol was brief (44.37 minutes). Adverse gastrointestinal tract effects were less apparent during continuous 24-hour infusion of butorphanol at a dosage that resulted in a mean plasma concentration of 29 ng/ml, compared with effects after a single IV injection. No adverse behavioral effects were observed during or after continuous infusion.

Conclusions and Clinical Relevance—Continuous IV infusion of butorphanol for 24 hours maintained plasma butorphanol concentrations within a range associated with analgesia. Adverse behavioral and gastrointestinal tract effects were minimized during infusion, compared with a single injection of butorphanol. Continuous infusion of butorphanol may be a useful treatment to induce analgesia in horses. (Am J Vet Res 2001;62:183–189)

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in American Journal of Veterinary Research


Objective—To determine whether substantial interobserver variation exists among diagnostic pathologists for descriptions of intestinal mucosal cell populations and whether histopathologic descriptions accurately predict when a patient does not have clinically evident intestinal disease.

Design—Comparative survey.

Sample Population—14 histologic slides of duodenal, ileal, or colonic tissue from 10 dogs and 3 cats.

Procedure—Each histologic slide was evaluated independently by 5 pathologists at 4 institutions. Pathologists, who had no knowledge of the tissues' origin, indicated whether slides were adequate for histologic evaluation and whether the tissue was normal or abnormal. They also identified the main infiltrating cell type in specimens that were considered abnormal, and whether infiltrates were mild, moderate, severe, or neoplastic.

Results—Quality of all slides was considered adequate or superior by at least 4 of the 5 pathologists. For intensity of mucosal cellular infiltrates, there was uniformity of opinion for 1 slide, near-uniformity for 6 slides, and nonuniformity for 7 slides. Five dogs did not have clinical evidence of intestinal disease, yet the pathologists' descriptions indicated that their intestinal tissue specimens were abnormal.

Conclusions and Clinical Relevance—Substantial interobserver variation was detected. Standardization of pathologic descriptions of intestinal tissue is necessary for meaningful comparisons with published articles. Clinicians must be cautious about correlating clinical signs and histopathologic descriptions of intestinal biopsy specimens. (J Am Vet Med Assoc 2002;220:1177–1182)

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in Journal of the American Veterinary Medical Association