Objective—To evaluate a method for experimental
induction of osteoarthritis in the hip joints of dogs.
Animals—12 mixed-breed dogs.
Procedure—A unilateral triple pelvic osteotomy was
performed. In 6 dogs, the iliac osteotomy was
repaired with 45° of internal rotation, reducing coverage
of the femoral head by the acetabulum. In the
other 6 dogs, the fragments were repaired in anatomic
alignment. Radiography, force plate evaluations, and
subjective lameness evaluations were performed
before and after surgery. Dogs were euthanatized 7
months after surgery, and samples of cartilage and
joint capsule were examined histologically.
Results—Subjective lameness scores, radiographic
appearance of the hip joints, and Norberg angles
were not significantly different between groups; however,
force plate evaluations did reveal significant differences
in vertical ground reaction forces. Femoral
head coverage was significantly decreased with rotation
of the acetabulum. Mild inflammatory changes
were discernible in the joint capsule and articular cartilage
of some dogs in both groups.
Conclusions and Clinical Relevance—Results suggest
that 45° internal rotation of the acetabulum does
not consistently induce biologically important
osteoarthritic changes in the hip joints of dogs.
(Am J Vet Res 2000;61:484–491)
Objective—To evaluate effects of zoledronate on
markers of bone metabolism in dogs after transection
of the cranial cruciate ligament (CrCL).
Animals—21 adult dogs.
Procedure—Unilateral CrCL transection was performed
arthroscopically. Dogs were allocated to 3
groups (control group, low-dose zoledronate
[10 µg/kg, SC, q 90 d for 12 months], and high-dose
zoledronate [25 µg/kg, SC, q 90 d for 12 months]).
Serum osteocalcin (OC), serum bone-specific alkaline
phosphatase (BAP), and urine pyridinoline and
deoxypyridinoline concentrations were measured at
0, 1, 3, 6, 9, and 12 months after surgery. Bone mineral
density (BMD) was determined in the distal portion
of the femur and proximal portion of the tibia via
computed tomography at each time point. Data were
analyzed by a repeated-measures ANOVA.
Results—Zoledronate inhibited OC in the high-dose
group at 9 and 12 months and at 12 months in the low-dose
group, compared with the control group. High-dose
zoledronate decreased BAP concentrations 3 and 9
months after surgery. In the control group, BMD was
decreased in the femoral condyle and caudal tibial
plateau. Zoledronate prevented significant BMD decreases
starting 1 month after transection, compared with
control dogs. In the caudomedial aspect of the tibial
plateau, both zoledronate groups had significant increases
in BMD after 3 months, compared with control dogs.
Conclusions and Clinical Relevance—Zoledronate
may reduce subchondral bone loss and effect markers
of bone metabolism in dogs with experimentally
induced instability of the stifle joint and subsequent
development of osteoarthritis. (Am J Vet Res
Objective—To examine the ability of preemptive administration of a proprietary neurokinin-1 (NK1) receptor antagonist to attenuate limb dysfunction associated with monosodium urate–induced synovitis in the stifle joints of dogs.
Animals—16 clinically normal adult mixed-breed dogs (8 males and 8 females).
Procedures—A crossover study was conducted in 2 phases. Dogs were assigned to 2 groups (8 dogs/group) and orally administered an NK1 receptor antagonist (3 mg/kg) or a control substance once daily for 4 days. Synovitis was then induced in the left stifle joint by intra-articular injection of monosodium urate. Investigators were not aware of treatment group assignments. Dogs were evaluated by use of subjective lameness scores during standing, walking, and trotting and by use of ground reaction force data 3, 6, 9, 12, and 24 hours after urate injection. After a 21-day washout period, the experiment was repeated with each dog administered the other treatment and injected with monosodium urate in the contralateral stifle joint.
Results—No significant differences were detected between the NK1 receptor antagonist and control treatments with regard to peak vertical force, vertical impulse area, or subjective evaluations of lameness during standing, walking, or trotting, except during walking 24 hours after monosodium urate injection.
Conclusions and Clinical Relevance—Preemptive administration of an NK1 receptor antagonist failed to significantly improve subjective or objective outcome measures in dogs with monosodium urate–induced synovitis.
Objective—To determine the plasma pharmacokinetics
of imipenem (5 mg/kg) after single-dose IV, IM,
and SC administrations in dogs and assess the ability
of plasma samples to inhibit the growth of Escherichia
coli in vitro.
Animals—6 adult dogs.
Procedure—A 3-way crossover design was used.
Plasma concentrations of imipenem were measured
after IV, IM, and SC administration by use of high-performance
liquid chromatography. An agar well antimicrobial
assay was performed with 3 E coli isolates
that included a reference strain and 2 multidrug-resistant
Results—Plasma concentrations of imipenem
remained above the reported minimum inhibitory concentration
for E coli (0.06 to 0.25 µg/mL) for a minimum
of 4 hours after IV, IM, and SC injections.
Harmonic mean and pseudo-standard deviation halflife
of imipenem was 0.80 ± 0.23, 0.92 ± 0.33, and
1.54 ± 1.02 hours after IV, IM, and SC administration,
respectively. Maximum plasma concentrations (Cmax)
of imipenem after IM and SC administration were
13.2 ± 4.06 and 8.8 ± 1.7 mg/L, respectively. Time
elapsed from drug administration until Cmax was 0.50
± 0.16 hours after IM and 0.83 ± 0.13 hours after SC
injection. Growth of all 3 E coli isolates was inhibited
in the agar well antimicrobial assay for 2 hours after
imipenem administration by all routes.
Conclusions and Clinical Relevance—Imipenem is
rapidly and completely absorbed from intramuscular
and subcutaneous tissues and effectively inhibits in
vitro growth of certain multidrug-resistant clinical isolates
of E coli. (Am J Vet Res 2003;64:694–699)
Objective—To compare preoperative administration
of meloxicam and butorphanol to perioperative administration
of butorphanol alone for control of postoperative
signs of pain in dogs.
Animals—40 client-owned dogs scheduled for surgical
repair of a cranial cruciate ligament rupture.
Procedure—Group-1 dogs received butorphanol (0.2
mg/kg, IV) and meloxicam (0.2 mg/kg, IV) just prior to
surgery. Group-2 dogs received butorphanol just prior
to surgery (0.2 mg/kg, IV) and at incision closure (0.1
mg/kg, IV). Pain assessment began 1 to 2 hours
before surgery and from extubation until 24 hours
after surgery by obtaining the following measurements:
the visual analog scale (VAS) score, cumulative
pain score (CPS), adjusted cumulative pain score,
modified cumulative pain score, and the adjusted
modified cumulative pain score (AMCPS). Serum cortisol
concentration was measured between 12 to 24
and between 1 to 2 hours prior to surgery, and at 30
minutes, and 1, 2, 4, 8, 18, and 24 hours after extubation.
Results—No significant differences between treatment
groups were observed in CPS or VAS score. At
8, 9, 10, and 11 hours after extubation, meloxicambutorphanol-
treated dogs had a significantly lower
AMCPS, compared with butorphanol-alone-treated
dogs. Total serum cortisol concentration (area under
the curve) during the measurement period was significantly
lower in meloxicam-butorphanol-treated
dogs, compared with butorphanol-alone treated dogs.
Conclusions and Clinical Relevance—Preoperative
single dose administration of meloxicam-butorphanol
is equivalent to or slightly better than the administration
of 2 perioperative doses of butorphanol for the
control of postoperative signs of pain in dogs. (Am J
Vet Res 2002;63:1557–1563)
Objective—To investigate the effect of therapeutic dosages of meloxicam on the plasma clearance of iohexol in healthy, euvolemic, conscious cats fed a sodium-replete diet.
Animals—6 healthy adult neutered male cats.
Procedures—For each treatment period in a masked, randomized, crossover study, cats were administered either no treatment or meloxicam. Iohexol clearance studies were performed before the treatment period began (baseline) and on the final day of the treatment period. Iohexol concentrations were determined by use of a high-performance liquid chromatography assay, and plasma iohexol clearance as a marker of glomerular filtration rate was calculated by use of a 1-compartment model.
Results—No significant treatment effect was detected. Mean ± SE iohexol clearance for cats administered meloxicam (3.31 ± 0.27 mL/min/kg) was not significantly different from mean baseline value for the meloxicam treatment period (3.07 ± 0.32 mL/min/kg).
Conclusions and Clinical Relevance—In this study, short-term meloxicam administration did not measurably alter the glomerular filtration rate as assessed via plasma clearance of iohexol. This suggests that renal prostaglandins in cats did not have a measurable effect on glomerular filtration rates in healthy, euvolemic, conscious states as determined on the basis of methods used in this study.
Objective—To investigate the ability of ABT-116 (a proprietary antagonist of transient receptor potential vanilloid type 1) administered at 2 doses to attenuate lameness in dogs with experimentally induced urate synovitis.
Animals—8 purpose-bred mixed-breed dogs.
Procedures—In a 4-way crossover study, dogs orally received each of low-dose ABT-116 treatment (LDA; 10 mg/kg), high-dose ABT-116 treatment (HDA; 30 mg/kg), firocoxib (5 mg/kg), and no treatment (nontreatment) once a day for 2 days, in a randomly assigned order. Synovitis was induced on the second day of each treatment period by intra-articular injection of either stifle joint with sodium urate, alternating between joints for each treatment period, beginning with the left stifle joint. Ground reaction forces, clinical lameness scores, and rectal temperature were assessed before the injection (baseline) and at various points afterward.
Results—Lameness scores at the 2-, 6-, and 12-hour assessment points were higher than baseline scores for HDA and nontreatment, whereas scores at the 2- and 6-hour points were higher than baseline scores for LDA. For firocoxib, there was no difference from baseline scores in lameness scores at any point. Compared with baseline values, peak vertical force and vertical impulse were lower at 2 and 6 hours for HDA and nontreatment and at 2 hours for LDA. No changes in these values were evident for firocoxib. The HDA or LDA resulted in higher rectal temperatures than did treatment with firocoxib or nothing, but those temperatures did not differ among treatments.
Conclusions and Clinical Relevance—HDA had no apparent effect on sodium urate–induced lameness; LDA did attenuate the lameness but not as completely as firocoxib treatment. High rectal temperature is an adverse effect of oral ABT-116 administration that may be of clinical concern.
Objective—To compare overground and treadmill-based gaits of dogs.
Animals —5 clinically normal adult mixed-breed dogs.
Procedures—To obtain dynamic gait data, 30 retroreflective markers were affixed bilaterally to specific regions of the hind limbs and pelvis of each dog. For each dog, 3-D joint motion data (sagittal [flexion and extension], transverse [internal and external rotation], and frontal [abduction and adduction] planes of motion) for the hip, femorotibial, and tarsal joints were acquired during walking and trotting through a calibrated testing space overground or on a treadmill. Comparison of data was performed via generalized indicator function analysis and Fourier analysis.
Results—Both overground and treadmill-based gaits produced similar waveforms in all planes of motion. Fourier analysis revealed no difference between overground and treadmill-based gaits in the sagittal plane of motion; however, small differences were detected between overground and treadmill-based gaits in the other 2 planes of motion. Additionally, femorotibial joint motion during walking did not differ among planes of motion. Generalized indicator function analysis was able to detect differences between overground and treadmill-based gait waveforms in all planes of motion for all joints during walking and trotting.
Conclusions and Clinical Relevance—In dogs, overground and treadmill-based gaits produced similar waveform shapes. Of the 3 planes of motion evaluated, only sagittal plane kinematic gait data were unaffected by mode of ambulation as determined via Fourier analysis. Sagittal kinematic gait data collected from dogs during overground or treadmill-based ambulation were comparable. However, analysis methods may affect data comparisons.
Objective—To assess effects of in vitro meloxicam exposure on metabolism in articular chondrocytes from dogs with naturally occurring osteoarthritis
Sample—Femoral head cartilage from 16 dogs undergoing total hip replacement
Procedures—Articular cartilage samples were obtained. Tissue sulfated glycosaminoglycan (SGAG), collagen, and DNA concentrations were measured. Collagen, SGAG, chondroitin sulfate 846, NO, prostaglandin E2 (PGE2), and matrix metalloproteinase (MMP)-2, MMP-3, MMP-9, and MMP-13 concentrations in culture medium were analyzed. Aggrecan, collagen II, MMP-2, MMP-3, MMP-9, MMP-13, ADAM metallopeptidase with thrombospondin type 1 motif (ADAMTS)-4, ADAMTS-5, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, TIMP-3, interleukin-1β, tumor necrosis factor-α, cyclooxygenase-1, cyclooxygenase-2, and nducible nitric oxide synthase gene expression were evaluated. Comparisons between tissues cultured without (control) and with meloxicam at concentrations of 0.3, 3.0, and 30.0 μg/mL for up to 30 days were performed by means of repeated-measures analysis.
Results—Meloxicam had no effect on chondrocyte SGAG, collagen, or DNA concentrations. Expression of ADAMTS-5 was significantly decreased in all groups on all days, compared with the day 0 value. On day 3, culture medium PGE2 concentrations were significantly lower in all meloxicam-treated groups, compared with values for controls, and values remained low. Culture medium MMP-3 concentrations were significantly lower on day 30 than on day 3 in all meloxicam-treated groups.
Conclusions and Clinical Relevance—Results suggested that in vitro meloxicam treatment of osteoarthritic canine cartilage for up to 30 days did not induce matrix degradation or stimulate MMP production. Meloxicam lowered PGE2 release from this tissue, and effects on tissue chondrocyte content and matrix composition were neutral.
Objective—To assess effects of zoledronic acid on biomarkers, radiographic scores, and gross articular cartilage changes in dogs with induced osteoarthritis.
Animals—21 purpose-bred hound-type dogs.
Procedures—The left stifle joint of each dog was examined arthroscopically to determine initial articular cartilage status, which was followed by cranial cruciate ligament (CrCL) transection to induce osteoarthritis. Dogs were assigned to 3 groups (control group, low dose [10 μg of zoledronic acid/kg], or high dose [25 μg of zoledronic acid/kg). Treatments were administered SC every 3 months for 1 year beginning the day after CrCL transection. Serum and synovial fluid samples and radiographs were obtained 0, 1, 3, 6, 9, and 12 months after transection. At 12 months, each joint was scored for cartilage defects. Serum and synovial fluid biomarkers of bone and cartilage turnover (bone-specific alkaline phosphatase, type I and II collagen, carboxy-propeptide of type II collagen, and chondroitin sulfate 846) were analyzed with ELISAs.
Results—The high-dose group had fewer total articular defects and lower severity scores in CrCL-transected stifle joints than did the control group. In addition, the high-dose group had significantly less change in collagenase cleavage of type I or II collagen in the synovial fluid at 1 and 3 months after CrCL transection than did the control group and also had greater changes in bone-specific alkaline phosphatase in synovial fluid at 3 months after CrCL transection than did the control group.
Conclusions and Clinical Relevance—Zoledronic acid had a chondroprotective effect in dogs with a transected CrCL.