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Abstract

Objective

To evaluate the effects of arthroscopic surgery, osteochondral fragmentation, and treatment with IV administered hyaluronate on histologic, histochemical, and biochemical measurements within the carpal joints of horses.

Animals

12 clinically normal horses, 2 to 7 years of age.

Procedure

Horses had an osteochondral fragment created at the distal aspect of the radiocarpal bone of 1 randomly chosen middle carpal joint to simulate osteochondral fragmentation. Horses were treated with 40 mg of hyaluronate or saline solution (placebo) intravenously once a week for 3 consecutive weeks (days 13, 20, and 27 after surgery). Treadmill exercise proceeded 5 days per week beginning 15 days, and ending 72 days, after surgery. Clinical evaluations were performed at the beginning and end of the study. Synovial fluid samples were obtained aseptically from both middle carpal joints on days 0, 13, 20, 27, 34, and 72 after surgery, and total protein, inflammatory cell, hyaluronate, glycosaminoglycan, and prostaglandin E2 concentrations were measured in each sample. All horses were euthanatized on day 72. Synovial membrane and articular cartilage were obtained for histologic evaluation. Articular cartilage samples were also obtained aseptically for determining glycosaminoglycan content and chondrocyte synthetic rate for glycosaminoglycans.

Results

Horses treated with hyaluronate intravenously had lower lameness scores (were less lame), significantly better synovial membrane histologic scores, and significantly lower concentrations of total protein and prostaglandin E2 within synovial fluid 72 days after surgery, compared with placebo-treated horses. Treatment with intravenously administered hyaluronate had no significant effects on glycosaminoglycan content, synthetic rate or morphologic scoring in articular cartilage, or other synovial fluid measurements.

Conclusion

Intravenously administered hyaluronate appears to alleviate signs of lameness by interacting with synoviocytes, and by decreasing production and release of inflammatory mediators. (Am J Vet Res 1997;58:1132–1140)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compare the analgesic and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs (NSAID), ketoprofen (2.20 and 3.63 mg/kg of body weight) and phenylbutazone (4.40 mg/kg), in an acute equine synovitis model.

Design

4 groups of 6 horses received NSAID or saline solution in a randomized design.

Animals

24 clinically normal mares and geldings.

Procedure

Left intercarpal joints were injected with sterile carrageenan to induce synovitis at the same time as IV administration of NSAID or saline solution. Clinical assessments were made and synovial fluid was withdrawn at 0, 1, 3, 6, 9, 12, 24, and 48 hours.

Results

The eicosanoids, prostaglandin E2 (PGE2) and leukotriene B4, increased in synovial fluid after synovitis induction in all horses then returned to near baseline by 48 hours. All NSAID-treated horses had decreased PGE2, compared with saline-treated horses. This effect lasted longer in phenylbutazone-treated horses than in ketoprofen-treated horses. There were no treatment effects on leukotriene B4. In saline-treated animals, lameness, joint temperature, and synovial fluid volume, protein concentration, and nucleated cells increased 3 to 12 hours after induction, with marked reduction by 48 hours. Only phenylbutazone treatment reduced lameness, joint temperature, and synovial fluid volume.

Conclusion

Phenylbutazone was more effective than ketoprofen in reducing lameness, joint temperature, synovial fluid volume, and synovial fluid PGE2. Results do not support lipoxygenase inhibition by either NSAID.

Clinical Relevance

This reversible model induced synovial fluid alterations similar to those observed in horses with septic arthritis. Results indicate that phenylbutazone may be more useful than ketoprofen in treating acute joint inflammation. (Am J Vet Res 1996;57:866–874)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate the effect on intramuscular blood flow (IMBF) and hemodynamic variables of 4 antihypotensive agents given during anesthesia.

Animals

8 ponies.

Procedure

Halothane-anesthetized ponies (n = 6) positioned in lateral recumbency received, on separate occasions, infusions of each of the following 4 agents in serially increasing dosages or saline solution: phenylephrine hydrochloride (0.25, 0.5, 1, and 2 μg/kg of body weight), dopamine (2.5, 5, 10, and 20 μg/kg), dobutamine (1, 2.5, 5, and 10 μg/kg), and dopexamine (0.5, 1, 5, and 10 μg/kg). Changes in IMBF (by laser-Doppler flowmetry) in nondependent and dependent triceps brachii muscles and cardiopulmonary variables were measured.

Results

Phenylephrine at all dosages failed to improve IMBF or cardiac index (CI), but increased mean arterial pressure (MAP) and systemic vascular resistance (SVR); 2 ponies had forelimb lameness on recovery. Dopamine (10 μg/kg/min) increased Cl, MAP, and IMBF in the dependant muscle. A higher dose (20 μg/kg/min) caused cardiac arrhythmias and muscular tremor. Dobutamine increased Cl, MAP, and IMBF of both forelimbs, effects being significant for 2.5 μg/kg/min, with further improvement as the dosage increased. In 2 ponies, 10 μg of dobutamine/kg/min caused cardiac arrhythmias. Dopexamine (1 and 5 μg/kg/min) increased Cl, MAP, and IMBF in the nondependent muscle, and 10 μg/kg/min caused muscular tremor, sweating, and arrhythmias. SVR was reduced after infusion of dopamine, dobutamine, or dopexamine.

Conclusion

During anesthesia of equids, an increase in CI and MAP is necessary to improve IMBF in the dependant forelimb.

Clinical Relevance

Of the agents investigated, dobutamine proved the most consistent in improving IMBF. (Am J Vet Res 1998;59:1463–1472)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate the effect of topically applied dimethylsulfoxide (DMSO) on lipopolysaccharide (LPS)-induced synovitis in the mid-carpal joint.

Animals

6 sound, healthy, adult horses (12 carpi).

Procedure

In a double-blinded, crossover, paired study with a 1-week washout period, mid-carpal joints were allocated to group 1 (DMSO, n = 6) or group 2 (control, n = 6). Each joint was injected with 1.3 ml (0.0125 ng/dl) of LPS to induce synovitis. For group-1 joints, DMSO gel (15 g; 90%) was applied after injection of LPS and at 12-hour intervals for 60 hours. Joints of group 2 received LPS, but not DMSO gel. All horses were evaluated by serial lameness examinations and synovial fluid analyses (total and differential WBC count and total protein concentration) at 12- hour intervals for 60 hours after LPS injection. Plasma and synovial fluid were obtained at baseline and 36 hours to document presence of DMSO.

Results

Mean WBC concentration was significantly (P < 0.05) lower in group-1, compared with group-2 joints, at 24 hours and had a trend to be lower at 36 hours. Mean total neutrophil count was significantly lower in group-1, compared with group-2 joints at 24 hours. In group-1 joints, DMSO was detected by use of gas chromatography in the synovial fluid of 5 of 6 joints and in plasma from 1 of 6 horses.

Conclusion

Topically applied DMSO penetrated into synovial fluid in sufficient quantities to be detected and to decrease joint inflammation. (Am J Vet Res 1998;59:1149-1152)

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To titrate a clinically effective eltenac dosage (0.1, 0.5, and 1.0 mg/kg of body weight), compared with vehicle only, and to compare efficacy of the most effective eltenac dosage with that of 1.1 mg of flunixin meglumine/kg.

Animals

40 healthy horses, ranked after model induction on the basis of lameness severity, were randomly assigned to 5 treatment groups, with 4 replicates of 10 horses each.

Procedure

On day -5, after surgical preparation of the left carpal region, 0.7 ml of Freund's complete adjuvant was injected into the intercarpal space. Horses were observed daily, from the day of carpitis induction to day 0, when stride length was used as the method of ranking horses for randomization to treatment assignment. Treatments were administered IV once daily for 3 consecutive days, starting on day 0. Prior to carpitis induction on day -5, and at time 0 (pretreatment). 2, 4, 12, 24, 36. 48, 60, 72, and 96 hours after treatment initiation, resting respiratory rate and pulse, rectal temperature, carpal circumference, carpal flexion angle, stride length, carpal hyperthermia, and signs of carpal pain were recorded.

Results

Compared with the vehicle and 0.1 mg of eltenac/kg, 0.5 and 1.0 mg/kg caused statistically significant improvements (ie, reduction of carpal circumference, increase in carpal flexion angle, and increase in stride length of the affected limb), but values did not differ significantly between the 2 dosages. Thus, a dose-response plateau for eltenac was reached at 0.5 mg/kg.

Comparison with flunixin meglumine at a dosage of 1.1 mg/kg did not indicate significant differences between the 2 treatment groups at the pivotal time of 96 hours for carpal circumference, carpal flexion angle, stride length, carpal hyperthermia, and signs of carpal pain. Adverse reactions were not observed.

Clinical Relevance

Under conditions of this study, a dosage plateau for eltenac was determined (0.5 mg/kg) that was statistically equivalent to eltenac (1.0 mg/kg) and flunixin meglumine (1.1 mg/kg) in a 3-day IV dosing regimen. (Am J Vet Res 1997;58:298–302)

Free access
in American Journal of Veterinary Research

Orthopedic problems are common in swine. In Scandinavia, the incidence of lameness is reported to be approximately 10% in young pigs, 1,2 with a prevalence of 8.8% in loose-housed adult swine. 3 In Australia, fibrinopurulent inflammation is a

Full access
in American Journal of Veterinary Research

Horses of all types of breeds and uses are susceptible to musculoskeletal diseases that result in lameness. Of all reported conditions, lameness ranks as one of the most common causes for poor performance in horses used for racing. 1

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in American Journal of Veterinary Research

eggs from hens treated PO with meloxicam. In a study 3 of lame broiler chickens, a single SC injection of meloxicam (5 mg/kg) improved mobility, compared with findings in control birds that received saline (0.9% NaCl) solution SC. Caplen et al 4

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in American Journal of Veterinary Research

administered PO to the study sheep (1.0 mg/kg) was determined from findings of an analgesic study 16 in which lameness was induced in sheep with turpentine. This higher dose was used as a result of a poor analgesic response observed when meloxicam was

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in American Journal of Veterinary Research

horses were geldings and owned by the University of California-Davis, Center for Equine Health. The study took place from March 2, 2021, to April 15, 2021. Horses were free from lameness at the walk and had no evidence of vascular abnormalities, carpal

Full access
in American Journal of Veterinary Research