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- Author or Editor: Michelle M. Taylor x
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Abstract
Objective—To determine effects of athletic conditioning on thyroid hormone concentrations in a population of healthy sled dogs.
Animals—19 healthy adult sled dogs.
Procedure—Serum concentrations of thyroxine (T4), triiodothyronine (T3), thyroid-stimulating hormone (TSH), free T4 (fT4), free T3 (fT3), and autoantibodies directed against T3, T4, and thyroglobulin were measured in sled dogs that were not in training (ie, nonracing season) and again after dogs had been training at maximum athletic potential for 4 months.
Results—Analysis revealed significant decreases in T4 and fT4 concentrations and a significant increase in TSH concentration for dogs in the peak training state, compared with concentrations for dogs in the untrained state. Serum concentrations of T4 and fT4 were less than established reference ranges during the peak training state for 11 of 19 and 8 of 19 dogs, respectively; fT4 concentration was greater than the established reference range in 9 of 19 dogs in the untrained state.
Conclusions and Clinical Relevance—Decreased total T4 and fT4 concentrations and increased serum concentrations of TSH were consistently measured during the peak training state in healthy sled dogs, compared with concentrations determined during the untrained state. Although thyroid hormone concentrations remained within the established reference ranges in many of the dogs, values that were outside the reference range in some dogs could potentially lead to an incorrect assessment of thyroid status. Endurance training has a profound impact on the thyroid hormone concentrations of competitive sled dogs. ( Am J Vet Res 2004;65:333–337)
Abstract
Objective—To determine the pharmacokinetics of butorphanol tartrate after IV and IM single-dose administration in red-tailed hawks (RTHs) and great horned owls (GHOs).
Animals—6 adult RTHs and 6 adult GHOs.
Procedures—Each bird received an injection of butorphanol (0.5 mg/kg) into either the right jugular vein (IVj) or the pectoral muscles in a crossover study (1-week interval between treatments). The GHOs also later received butorphanol (0.5 mg/kg) via injection into a medial metatarsal vein (IVm). During each 24-hour postinjection period, blood samples were collected from each bird; plasma butorphanol concentrations were determined via liquid chromatography-mass spectrometry.
Results—2- and 1-compartment models best fit the IV and IM pharmacokinetic data, respectively, in both species. Terminal half-lives of butorphanol were 0.94 ± 0.30 hours (IVj) and 0.94 ± 0.26 hours (IM) for RTHs and 1.79 ± 1.36 hours (IVj), 1.84 ± 1.56 hours (IM), and 1.19 ± 0.34 hours (IVm) for GHOs. In GHOs, area under the curve (0 to infinity) for butorphanol after IVj or IM administration exceeded values in RTHs; GHO values after IM and IVm administration were less than those after IVj administration. Plasma butorphanol clearance was significantly more rapid in the RTHs. Bioavailability of butorphanol administered IM was 97.6 ± 33.2% (RTHs) and 88.8 ± 4.8% (GHOs).
Conclusions and Clinical Relevance—In RTHs and GHOs, butorphanol was rapidly absorbed and distributed via all routes of administration; the drug's rapid terminal half-life indicated that published dosing intervals for birds may be inadequate in RTHs and GHOs.
Summary
Prevalence of intraoperative contamination of the eyelids, conjunctival sac, and aqueous humor of 50 canine eyes that underwent elective cataract surgery was determined, and the short-term outcomes for contaminated and noncontaminated eyes were compared by scoring media clarity, pupil size and shape, and behavioral evidence of vision during the initial 30-day postoperative period. Results of bacteriologic culture of anterior chamber samples were positive for 12 of the 50 (24%) eyes, but anterior chamber contamination was unrelated to results of bacteriologic culture of eyelids or conjunctival sac swab samples. Eyes undergoing phacoemulsification were less likely to be contaminated than were eyes undergoing intra- or extracapsular extraction. Eyes undergoing intra- or extracapsular extraction and eyes with anterior chamber contamination had a greater likelihood of developing glaucoma postoperatively. We did not detect an association between intraocular contamination and the surgeon performing the operation, the need for postoperative administration of tissue plasminogen activator, or the presence or absence of diabetes mellitus. Also, we did not detect any differences in outcome between eyes with and without intraocular contamination. Despite intraoperative bacterial contamination of the anterior chamber, bacterial endophthalmitis did not develop in any of the eyes.
