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Abstract

Objective—To evaluate cyclooxygenase (COX) selectivity of several nonsteroidal anti-inflammatory drugs (NSAID) in canine blood in vitro.

Animals—11 healthy adult male hound crosses.

Procedure—9 NSAID were studied at 5 concentrations. Thromboxane B2 (TxB2) was assayed as a measure of COX-1 activity in clotted blood. Prostaglandin E2 (PGE2) was assayed as a measure of COX-2 activity in heparinized, lipopolysaccharide (LPS)-stimulated blood. All assays were competitive ELISA tests. Cyclooxygenase selectivity was expressed as a ratio of the concentration of an NSAID that inhibited 50% of the activity (IC50) of COX-1 to the IC50 of COX-2. A separate ratio of the concentration that inhibited 80% of COX activity (IC80) was also determined. A ratio of < 1.0 indicated selectivity for COX-1, whereas a ratio of > 1.0 indicated COX-2 selectivity.

Results—Ketoprofen, aspirin, and etodolac were COX-1 selective. Piroxicam, meloxicam, and carprofen had COX-2 selectivity. The IC50 and IC80 values were similar for most NSAID.

Conclusion and Clinical Relevance—This methodology provides repeatable data from individual dogs and is comparable to results of previous in vitro and ex vivo models. Findings are also consistent with those of canine studies performed in vivo, suggesting that this is a viable in vitro assessment of the COX selectivity of NSAID in dogs. (Am J Vet Res 2002;63:91–94)

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

Summary

Detection of autoantibody, complement, or both bound to rbc is an essential requirement for unequivocal diagnosis of immune-mediated hemolytic anemia in dogs. An enzyme-linked antiglobulin test was adapted for laboratory diagnosis of this disease. The refinement and routine use of this assay have allowed further observation of the pathogenesis of the disease process. In particular, degree of hemolysis can be related to the degree of rbc sensitization associated with primary immune-mediated hemolytic anemia, and this correlation is highest for IgG autoantibody. Results indicate that autoantibody isotype might have an important role in the hemolytic process.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate in vivo activityin dogs of meloxicam or aspirin, previously shown in vitro to be a selective cyclooxygenase-2 (COX-2) inhibitor (COX-1 sparing drug), or a nonselective COX inhibitor, respectively.

Animals—12 male dogs with unilateral osteoarthritis of the stifle joint.

Procedure—Each dog was treated in a crossover design with aspirin or meloxicam for 21 days. Prostaglandin E2 (PGE2) concentrations were measured at days 0 (baseline), 7, and 21 of each treatment period in lipopolysaccharide (LPS)-stimulated blood, synovial fluid collected by arthrocentesis, and endoscopic gastric mucosal biopsy specimens. Thromboxane B2 (TXB2) was evaluated in blood on days 0, 7, and 21 of each treatment period.

Results—Aspirin administration significantly suppressed PGE2 concentrations in blood, gastric mucosa, synovial fluid, and suppressed TXB2 concentration in blood at days 7 and 21. Meloxicam administration significantly suppressed PGE2 concentrations in blood and synovial fluid at days 7 and 21, but had no effect on concentrations of TXB2 in blood or PGE2 in gastric mucosa. Suppression of LPS-stimulated PGE2 concentrations in blood and synovial fluid by aspirin and meloxicam administration is consistent with activity against the COX-2 isoenzyme. Suppression of concentrations of PGE2 in the gastric mucosa and TXB2 in blood by aspirin administration is consistent with activity against COX-1. Meloxicam, in contrast, had a minimal effect on functions mediated by COX-1.

Conclusions and Clinical Relevance—Meloxicam acts in vivo in dogs as a COX-1 sparing drug on target tissues by sparing gastric PGE2 synthesis while retaining antiprostaglandin effects within inflamed joints. (Am J Vet Res 2002;63:1527–1531)

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in American Journal of Veterinary Research

Abstract

CASE DESCRIPTION

A 36-kg (79-lb) castrated male Greyhound (dog 1) and a 25-kg (55 lb) spayed female Greyhound (dog 2) underwent general anesthesia for dental care with similar perianesthetic protocols on multiple occasions from 2013 to 2016. Both dogs had periodontal disease but were otherwise deemed healthy. Both dogs developed clinically relevant hyperkalemia, with signs including loss of P waves on ECG tracings, during multiple anesthetic events.

CLINICAL FINDINGS

Dog 1 developed hyperkalemia during 2 of 2 anesthetic events, with ECG changes noted during the first event. Dog 2 developed hyperkalemia during 3 of 4 anesthetic events, with ECG changes identified during the second and third events. Serum potassium concentration for both dogs was within the reference range prior to and between anesthetic events. No underlying etiopathogenesis for hyperkalemia was identified for either dog.

TREATMENT AND OUTCOME

In each hyperkalemic event, the clinician stopped the dental procedure and continued to provide supportive care and monitoring while the dog recovered from anesthesia. The ECG changes resolved, and serum potassium concentration returned to the reference range rapidly after inhalant anesthetic administration was discontinued. The dogs were discharged from the hospital without further complications.

CLINICAL RELEVANCE

Hyperkalemia in anesthetized Greyhounds resulted in serious cardiac conduction abnormalities, which could be potentially fatal if not recognized and promptly treated. Further investigation into the etiopathogenesis, prevention and treatment strategies, and genetic or familial components of this condition is indicated.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To identify consistent relevant mechanisms of small intestinal dysfunction in cats with experimentally induced feline immunodeficiency virus infection (FIV) that developed chronic diarrhea during the time they were being used in studies of pathogenicity and transmission of FIV.

Animals

10 cats.

Procedure

The following investigative tests and techniques were performed on each of the cats: routine hematologic and serum biochemical analyses; urinalysis; fecal parasitologic and microbiologic examinations; breath hydrogen lactulose (BH2LT) and xylose (BH2XT) tests; intestinal permeability test; endoscopic examination of the intestinal mucosa; bacteriologic culture of endoscopically collected small intestinal juice; and histologic examination of endoscopically obtained intestinal biopsy specimens.

Results

Neutrophilia was evident in 3 cats, and lymphopenia was detected in 2 cats. Serum biochemical abnormalities were not observed. Urinalysis results were unremarkable. Fecal bacteriologic and parasitologic results were normal, except for isolation of Campylobacter sp from 1 cat. Abnormal BH2XT values suggestive of d-xylose malabsorption were identified in 2 cats, and BH2LT values indicated evidence of small intestinal bacterial overgrowth in 1 cat. Finally, permeability test results, quantitation of bacterial flora from the proximal part of the small intestine and histologic examination of biopsy specimens did not reveal any abnormalities.

Conclusions

Enteric pathogens did not account for the development of diarrhea in cats with experimentally induced FIV infection, and consistent relevant mechanisms of small intestinal dysfunction were not identified. (Am J Vet Res 1998;59:569–574)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To investigate changes in the duodenal flora of healthy cats over time, and evaluate the effect of dietary supplementation with fructo-oligosaccharides (FOS).

Animals

12 healthy, barrier-maintained, specific pathogen-free cats.

Procedure

Duodenal juice for bacteriologic examination was collected via oral endoscopy 5 times from each cat over a 32-week period. Cats were allotted randomly to 2 groups, and a crossover design study, during which they were fed either a replete dry (basal) diet or, for 12 consecutive weeks, basal diet supplemented with 0.75% FOS, was done. Samples (3 from cats fed the basal and 2 from cats fed the FOS diet) were collected for a minimum of 6 weeks after commencement of feeding, and a minimum of 6 weeks apart.

Results

Mean aerobic, anaerobic, and total bacterial counts did not differ significantly among sample collection times. After pooling of the results, mean (± SD) log10 colony-forming units (CFU) of aerobic, anaerobic, and total bacteria/ml were 5.5 ± 1.1, 4.8 ± 1.0 and 5.6 ± 1.1, respectively. However, individual cats had considerable variation in counts: mean (range) intraindividual coefficients of variation were: 19.0 (6.1 to 34.2), 19.9 (4.8 to 35.5), and 18.1 (5.5 to 32.6)%, respectively. In 1 cat, total bacterial count varied between < 3.0 and 6.3 CFU/ml. Bacterial flora varied qualitatively: only Enterococcus faecalis, Clostridium perfringens, Bacteroides, Pasteurella, and Streptococcus spp, and unidentified gram-negative (aerobic) rods were present in > 50% of the samples.

Conclusions

Wide quantitative and qualitative variation in the duodenal flora of healthy cats was observed over time, which was not affected by dietary supplementation with FOS. (Am J Vet Res 1998;59:431–435)

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate a novel prosthesis technique for extracapsular stabilization of cranial cruciate ligament (CCL)–deficient stifle joints in adult cattle.

SAMPLE

13 cadaveric bovine stifle joint specimens.

PROCEDURES

In the first of 3 study phases, the most isometric points on the distal aspect of the femur (distal femur) and proximal aspect of the tibia (proximal tibia) were determined from measurements obtained from lateromedial radiographs of a stifle joint specimen maintained at angles of 135°, 90°, 65°, and 35°. During phase 2, 800-lb-test monofilament nylon leader line was cut into 73-cm-long segments. Each segment was secured in a loop by use of 2, 3, or 4 crimping sleeves such that there were 12 replicates for each construct. Each loop was distracted to failure at a constant rate of 1 mm/s. Mean force at failure and elongation and mode of failure were compared among the 3 constructs. During phase 3, bone tunnels were created in the distal femur and proximal tibia at the isometric points identified during phase 1 in each of 12 CCL-deficient stifle joint specimens. The 3-sleeve construct was applied to each specimen. Specimens were distracted to failure at a constant rate of 1 mm/s.

RESULTS

Among the 3 constructs evaluated, the 3-sleeve construct was considered optimal in terms of strength and amount of foreign material. In phase 3, all replicates failed because of suture slippage.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of 800-lb-test monofilament nylon leader line as a prosthesis might be a viable alternative for extracapsular stabilization of CCL-deficient stifle joints in adult cattle. Further in vivo studies are necessary.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To evaluate clearance, antibody responses, potential shedding, and histologic lesions in reproductive tissues of adult bison bulls after vaccination with Brucella abortus strain RB51.

Animals

61 two- and 3-year-old bison bulls.

Procedure

12 bison bulls were vaccinated SC with B abortus strain RB51, 3 were inoculated SC with 0.15M NaCI, and antibody responses were evaluated. Various specimens were obtained to evaluate bacterial shedding. Four vaccinates and 1 control were necropsied 10, 20, and 30 weeks after vaccination. In a separate experiment, bison bulls were vaccinated SC with 0.15M NaCI, or by hand or ballistically with strain RB51. Antibody responses were monitored 6 weeks after vaccination and during necropsy 13 weeks after vaccination. Tissue specimens obtained during necropsy from both studies were evaluated bacteriologically and histologically.

Results

Strain RB51 was recovered at various times from semen of 3 of 12 vaccinated bison bulls in experiment 1. During necropsy, strain RB51 was recovered 10 and 20, but not 30, weeks after vaccination. In experiment 2, strain RB51 was recovered from lymphoid tissues of hand- and ballistic-vaccinated bison bulls during necropsy. In both experiments, microscopic lesions in testes, epididymis, and seminal vesicles were minimal and did not differ between strain RB51-vaccinated and saline-inoculated bison bulls.

Conclusions and Clinical Relevance

Strain RB51 does not induce relevant inflammatory lesions in reproductive tissues of adult bison bulls. Shedding of strain RB51 in semen may be transient in some bison bulls; however, the importance of this observation is unknown. (Am J Vet Res 1999;60:905–908)

Free access
in American Journal of Veterinary Research