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Summary

The cardiopulmonary, anesthetic, and postanesthetic effects of an iv infusion of the hypnotic agent propofol were assessed in 6 Greyhounds and 7 non-Greyhounds. After im injection of acetylpromazine and atropine, a bolus injection of propofol sufficient to allow endotracheal intubation (mean ± sem = 4.0 ± 0.3 mg/kg of body weight in Greyhounds; 3.2 ± 0.1 mg/kg in non-Greyhounds) was administered, followed by continuous infusion at a rate of 0.4 mg/kg/min for 60 minutes, during which time dogs breathed 100% oxygen.

In 23% of all dogs (3 of 13), apnea developed after initial bolus administration of propofol. Arterial blood pressure was well maintained in all dogs, but heart and respiratory rates were decreased significantly (P < 0.05) during the infusion in Greyhounds. In Greyhounds, mild respiratory acidosis developed after 45 minutes, whereas arterial carbon dioxide tension was increased at all times after propofol administration in non-Greyhounds. In all dogs, pcv and total plasma proteins were unaffected by propofol. Rectal temperature decreased during treatment. Muscle tremors were observed in approximately 50% of dogs (in 3 of 6 Greyhounds and 3 of 7 non-Greyhounds) during and after infusion of propofol.

Non-Greyhounds lifted their heads, assumed sternal recumbency, and stood 10 ± 1, 15 ± 3, and 28 ± 5 minutes, respectively, after the end of the infusion; in Greyhounds, the corresponding times were 36 ± 4, 43 ± 6, and 63 ± 7 minutes.

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To investigate the pharmacokinetics of metformin hydrochloride in healthy dogs after IV and oral bolus administrations and determine the oral dose of metformin that yields serum concentrations equivalent to those thought to be effective in humans.

ANIMALS 7 healthy adult mixed-breed dogs.

PROCEDURES Each dog was given a single dose of metformin IV (mean ± SD dose, 24.77 ± 0.60 mg/kg) or PO (mean dose, 19.14 ± 2.78 mg/kg) with a 1-week washout period between treatments. For each treatment, blood samples were collected before and at intervals up to 72 hours after metformin administration. Seventy-two hours after the crossover study, each dog was administered metformin (mean dose, 13.57 ± 0.55 mg/kg), PO, twice daily for 7 days. Blood samples were taken before treatment initiation on day 0 and immediately before the morning drug administration on days 2, 4, 6, and 7. Serum metformin concentrations were determined by means of a validated flow injection analysis–tandem mass spectrometry method.

RESULTS After IV or oral administration to the 7 dogs, there was high interindividual variability in mean serum metformin concentrations over time. Mean ± SD half-life of metformin following IV administration was 20.4 ± 4.1 hours. The mean time to maximum serum concentration was 2.5 ± 0.4 hours. Mean systemic clearance and volume of distribution were 24.1 ± 7.8 mL/min/kg and 44.8 ± 23.5 L/kg, respectively. The mean oral bioavailability was 31%.

CONCLUSIONS AND CLINICAL RELEVANCE The study data indicated that the general disposition pattern and bioavailability of metformin in dogs are similar to those reported for cats and humans.

Full access
in American Journal of Veterinary Research

Objective

To assess the efficacy of etodolac in improving hind limb function in dogs with osteoarthritis of the hip joint.

Design

Prospective study.

Animals

100 client-owned dogs with clinical signs of osteoarthritis of the hip joint.

Procedure

Baseline ground reaction forces and subjective assessment scores were collected twice at a 7- to 10-day interval. After meeting entrance criteria, dogs were randomly assigned to the following 3 treatment groups: control group (0 mg of etodolac), low-dosage group (135 mg of etodolac), or high-dosage group (450 mg of etodolac). Dogs were treated once daily for 8 days, and gait analysis was repeated on day 8.

Results

On day 8 of treatment, vertical impulse and vertical peak force values for low- and high-dosage groups were significantly greater than baseline values within each group. On day 8, vertical impulse values from the high-dosage group were significantly greater than values from the low-dosage group. Vertical peak forces for the low- and high-dosage groups were significantly greater at 8 days than that of the control group. Analysis of the effect of evaluation center (site) on treatment outcome did not reveal a significant effect.

Clinical Implications

Etodolac administration for 8 days improved ground reaction forces in dogs with osteoarthritis of the hip joint. Improvement in force transmission was dosage dependent for the primary outcome measurement (vertical impulse). Results of the study indicate that etodolac is well tolerated by dogs, with minimal adverse effects during an 8-day treatment period. (J Am Vet Med Assoc 1999;214:206–210)

Free access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To evaluate the pharmacokinetics and bioavailability of 2 doses of orbifloxacin in rabbits.

ANIMALS 6 healthy purpose-bred adult female New Zealand White rabbits (Oryctolagus cuniculus).

PROCEDURES Each of 3 rabbits received orbifloxacin at either 10 or 20 mg/kg, PO. Then, after a 1-week washout period, they received the same dose IV. Blood samples were collected from each rabbit at 0, 0.25, 0.5, 1, 2, 4, 6, 12, and 24 hours after drug administration. Plasma orbifloxacin concentration was measured with liquid chromatography–tandem mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental analysis for data obtained following PO administration and noncompartmental and compartmental analyses for data obtained following IV administration.

RESULTS Following oral administration, the mean ± SD peak plasma orbifloxacin concentration was 1.66 ± 0.51 μg/mL for rabbits administered the 10 mg/kg dose and 3.00 ± 0.97 μg/mL for rabbits administered the 20 mg/kg dose and was attained at 2 hours after drug administration. The mean ± SD half-life of orbifloxacin in plasma was 7.3 ± 1.1 hours for rabbits administered the 10 mg/kg dose and 8.6 ± 0.55 hours for rabbits administered the 20 mg/kg dose. Mean bioavailability was 52.5% for rabbits administered the 10 mg/kg dose and 46.5% for rabbits administered the 20 mg/kg dose.

CONCLUSIONS AND CLINICAL RELEVANCE Results provided pharmacokinetic properties for 2 doses (10 mg/kg and 20 mg/kg) of orbifloxacin oral suspension in rabbits. Further studies are necessary to determine the protein-binding activity of orbifloxacin in rabbits before dosages for the treatment of common pathogens in this species are recommended.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate 4 rapid supravital stains and 3 preparation techniques for use in the intraoperative diagnosis of intracranial lesions.

Animals—10 dogs and 1 cat euthanatized for intracranial lesions.

Procedure—Specimens were taken from lesions and slides prepared, using 3 techniques: touch impression, medium-pressure impression, or smear preparation. Preparations were then stained with 4 stains: modified Wright stain, May-Grünwald-Giemsa, toluidine blue, and zynostain and examined in a blinded randomized fashion. Cytologic diagnosis was compared with histopathologic diagnosis and classified on the basis of identification of the pathologic process and specific diagnosis into the following categories: complete correlation, partial correlation, or no correlation.

Results—An overall diagnostic accuracy of 81% (107/132) was achieved on the basis of a combination of partial and complete correlation. Of the stains examined, modified Wright stain appeared to be most accurate, with complete correlation in 17 of 33 (52%) specimens and partial correlation in 12 of 33 (36%) specimens. Of the preparation methods, touch preparation and smear preparation provided the most accurate results, with an overall diagnostic accuracy of 82% (36/44) for both methods. However, smear preparations appeared to be of greater diagnostic value, with fewer nondiagnostic specimens, compared with touch preparations.

Conclusions and Clinical Relevance—Cytologic preparations provide a useful diagnostic tool for the intraoperative diagnosis of intracranial lesions. All stains examined yielded promising results, the most accurate of which appeared to be the modified Wright stain. The smear preparation appeared to be the preparation method of greatest diagnostic value. (Am J Vet Res 2002;63:381–386)

Full access
in American Journal of Veterinary Research

Summary

The medical records of 31 dogs diagnosed with prostatic carcinoma at the teaching hospital between January 1970 and October 1987 were reviewed to determine whether gender status had an effect on the clinical features or biologic behavior of the disease. The only Significant difference between sexually intact and castrated dogs was increased prevalence of pulmonary metastasis in castrated dogs.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine whether the prostaglandin E1 analogue, misoprostol, could preserve renal function in dogs receiving nephrotoxic doses of gentamicin.

Animals

12 (6/group) healthy sexually intact male dogs.

Procedure

All dogs were given high doses of gentamicin (10 mg/kg of body weight, IV, q 8 h, for 8 consecutive days). Six dogs (treatment group) received misoprostol (3 μg/kg, PO, q 8 h for the duration of the study) and 6 dogs (control group) received vehicle (1 capsule, PO, q 8 h). Renal function was assessed before treatment (day 0) and on days 3, 6, 9, and 11 after initiation of treatment by measurement of serum biochemical variables, urine specific gravity, and exogenous creatinine clearance. Serum electrolyte and protein concentrations and presence of proteinuria, glycosuria, and cylindruria were also determined. At the end of the study, renal histopathologic changes were evaluated.

Results

Dogs receiving misoprostol had significant reduction in exogenous creatinine clearance with time, compared with dogs receiving vehicle (P = 0.0264). Dogs receiving misoprostol tended to develop more severe azotemia, hyperphosphatemia, and renal histopathologic changes; however, results were not significantly different between groups.

Conclusion

Misoprostol (3 μg/kg, PO, q 8 h) did not preserve renal function and may have exacerbated gentamicin-induced nephrotoxicosis in this group of dogs.

Clinical Relevance

Supplementation of vasodilatory prostanoids may exacerbate renal dysfunction in dogs receiving high doses of gentamicin. (Am J Vet Res 1998;59:1048–1054)

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine whether extent of collateral circulation would change during temporary occlusion of the caudal vena cava (CVC) in ferrets (Mustela putorius), a pressure change would occur caudal to the occlusion, and differences would exist between the sexes with respect to those changes.

ANIMALS 8 adult ferrets (4 castrated males and 4 spayed females).

PROCEDURES Ferrets were anesthetized. A balloon occlusion catheter was introduced through a jugular vein, passed into the CVC by use of fluoroscopy, positioned cranial to the right renal vein, and inflated for 20 minutes. Venography was performed 5 and 15 minutes after occlusion. Pressure in the CVC caudal to the occlusion was measured continuously. A CBC, plasma biochemical analysis, and urinalysis were performed immediately after the procedure and 2 or 3 days later.

RESULTS All 8 ferrets survived the procedure; no differences were apparent between the sexes. Vessels providing collateral circulation were identified in all ferrets, indicating blood flow to the paravertebral venous plexus. Complications observed prior to occlusion included atrial and ventricular premature contractions. Complications after occlusion included bradycardia, seizures, and extravasation of contrast medium. Mean baseline CVC pressure was 5.4 cm H2O. During occlusion, 6 ferrets had a moderate increase in CVC pressure (mean, 24.3 cm H2O) and 2 ferrets had a marked increase in CVC pressure to > 55.0 cm H2O.

CONCLUSIONS AND CLINICAL RELEVANCE Caval occlusion for 20 minutes was performed in healthy ferrets with minimal adverse effects noted within the follow-up period and no apparent differences between sexes. The CVC pressure during occlusion may be prognostic in ferrets undergoing surgical ligation of the CVC, which commonly occurs during adrenal tumor resection.

Full access
in American Journal of Veterinary Research