Objective—To compare microcrack density and
length in the proximal and distal metaphyses of the
humerus and radius in dogs.
Sample Population—Left humerus and radius from
each of 10 dogs of medium to large size.
Procedure—Metaphyseal specimens were bulk
stained in 1% basic fuchsin in graded alcohols and
embedded in methylmethacrylate. For quantification
of fatigue-induced microscopic damage, transverse
sections were prepared from proximal and distal
metaphyseal regions, and length and density of microcracks
were determined, using light microscopy.
Results—Bone region, age, and body weight were
not significantly associated with microcrack density
Conclusions and Clinical Relevance—The hypothesis
that fatigue-induced injury (increased microcrack
density and length) caused by cyclic loading associated
with daily activity is greater in bone regions prone to
development of osteosarcoma was not supported by
data from this study. (Am J Vet Res 2000;61:6–8)
Objective—To quantify geometric, inertial, and histomorphometric
properties at the mid-diaphyseal level
of left and right metacarpal bones (MCB) of racing
Sample Population—MCB from 7 racing Greyhounds
euthanatized for reasons unrelated to MCB
Procedures—Mid-diaphyseal transverse sections of
left and right MCB were stained with H&E or microradiographed.
Images of stained sections were digitized,
and cross-sectional area, cortical area, and maximum
and minimum area moments of inertia of each
bone were determined. Histomorphometric data
(osteonal density, osteonal birefringence, and
endosteal new lamellar bone thickness) were collected
in 4 quadrants (dorsal, palmar, lateral, medial).
Values were compared between limbs and among
bones and quadrants.
Results—Cross-sectional area, cortical area, and
maximum and minimum moments of inertia of left
MCB-IV and -V were significantly greater, compared
with contralateral bones. Overall osteonal densities in
the dorsal quadrants of left MCB were greater, compared
with lateral and medial quadrants. Also, percentage
of birefringent osteons was significantly
greater in the dorsal quadrant of left MCB-III, -IV, and
-V, compared with the palmar quadrant. Thickness of
new endosteal lamellar bone was not significantly
influenced by limb, bone, or quadrant.
Conclusions and Clinical Relevance—Increased
cortical thickness and geometric properties of left
MCB-IV and -V of Greyhounds, together with altered
turnover and orientation of osteons in the dorsal
quadrants of left MCB, are site-specific adaptive
responses associated with asymmetric cyclic loading
as a result of racing on circular tracks. Site-specific
adaptive remodeling may be important in the
etiopathogenesis of fatigue fractures in racing Greyhounds.
(Am J Vet Res 2001;62:787–793)
Dog owners are increasingly interested in using commercially available testing panels to learn about the genetics of their pets, both to identify breed ancestry and to screen for specific genetic diseases. Helping owners interpret and understand results from genetic screening panels is becoming an important issue facing veterinarians. The objective of this review article is to introduce basic concepts behind genetic studies and current genetic screening tests while highlighting their value in veterinary medicine. The potential uses and limitations of commercially available genetic testing panels as screening tests are discussed, including appropriate cautions regarding the interpretation of results. Future directions, particularly with regard to the study of common complex genetic diseases, are also described.
Objective—To evaluate efficacy and adverse effects of leflunomide for the treatment of naturally occurring immune-mediated polyarthritis (IMPA) in dogs.
Design—Retrospective case series.
Animals—14 dogs with cytologically confirmed IMPA.
Procedures—Medical records were used to identify dogs with a diagnosis of IMPA that were treated with leflunomide. Signalment, radiographic findings, laboratory data, dosage of leflunomide, treatment duration, treatment response, and occurrence of adverse effects were determined from medical records.
Results—Mean ± SD initial dosage of leflunomide was 3.0 ± 0.5 mg/kg (1.4 ± 0.2 mg/lb) PO once daily. Treatment duration for the initial starting dosage ranged from 1 to 6 weeks. Of the 14 dogs treated with leflunomide, 8 had complete resolution of clinical signs of IMPA initially, 5 had partial response to treatment, and 1 had minimal response to treatment. Adverse effects from treatment with leflunomide were not observed during the treatment period.
Conclusions and Clinical Relevance—Oral administration of leflunomide was a safe and effective alternative to oral administration of corticosteroids for treatment of IMPA in dogs. On the basis of findings in this study, a starting dosage for leflunomide of 3 to 4 mg/kg (1.4 to 1.8 mg/lb) PO once daily for at least 6 weeks before making dose adjustments is recommended. Dose adjustments should be based on cytologic evaluation of synovial fluid and clinical signs of IMPA. Hematologic variables, serum biochemical analysis results, and clinical signs of IMPA should be monitored for evidence of adverse effects to treatment with leflunomide.
Objective—To determine the effect of weight reduction
on clinical signs of lameness among overweight
dogs with clinical and radiographic signs of hip
Design—Nonblinded prospective clinical trial.
Animals—9 client-owned dogs with radiographic
signs of hip osteoarthritis that weighed 11 to 12%
greater than their ideal body weight and were examined
because of hind limb lameness.
Procedure—Dogs were weighed, and baseline body
condition, hind limb lameness, and hip function
scores were assigned. Severity of lameness was
scored using a numerical rating scale and a visual analogue
scale. Dogs were fed a restricted-calorie diet,
with amount of diet fed calculated to provide 60% of
the calories needed to maintain the dogs' current
weights. Evaluations were repeated midway through
and at the end of the weight-loss period.
Results—Dogs lost between 11 and 18% of initial
body weight. Body weight, body condition score, and
severity of hind limb lameness were all significantly
decreased at the end of the weight-loss period.
Conclusions and Clinical Relevance—Results suggest
that in overweight dogs with hind limb lameness
secondary to hip osteoarthritis, weight reduction alone
may result in a substantial improvement in clinical lameness.
(J Am Vet Med Assoc 2000;216:1089–1091)
Objective—To evaluate whether body size and
anatomic site influence the quantity of bone microdamage
in dogs without osteosarcoma (OS).
Sample Population—Pairs of radii were collected
from 10 small dogs (< 15 kg) and 10 large dogs (> 25
Procedure—Specimens were stained in basic fuchsin
for bone microdamage. Transverse sections were cut
from each proximal and distal radial metaphysis at 15
and 85% of bone length. The following variables were
determined for each region: mean microcrack length
(CrLe, µm), microcrack density (CrDn,
microcracks/mm2), microcrack surface density
(CrSDn, µm/mm2), and estimated activation frequency
Results—Metaphyseal region did not significantly
influence CrDn, CrLe, and CrSDn. The CrDn and
CrSDn were influenced by body size, with microdamage
being increased in large dogs, compared with
small dogs. However, mean CrLe was not significantly
influenced by body size. Acf significantly decreased
with age and was significantly decreased in large
dogs and in the distal radial metaphysis, compared
with small dogs and the proximal radial metaphysis,
Conclusion and Clinical Relevance—Our data did
not reveal an increase in microdamage or remodeling
at the OS predilection site (ie, the distal metaphysis
of the radius), suggesting that induction of microdamage
and an associated increase in bone remodeling
are unlikely to be an important risk factor for
induction of OS. (Am J Vet Res 2002;63:896–899)
Objective—To determine prevalence of bacterial contamination
of surgical suction tips.
Sample Population—Surgical tips used during 44
surgical procedures performed on 42 dogs and 2 cats.
Procedure—Surgical procedures were classified into
1 of 3 categories according to degree of bacterial contamination
of the surgical site (clean, clean-contaminated,
contaminated). Two sets of suction apparatuses
were used for test and control suction tips. Test
tips were used normally to suction blood and fluid,
whereas control tips were placed on the surgical
drapes but not in the surgical wound. Suction tips
were collected aseptically and placed into thioglycolate
broth tubes for qualitative aerobic and anaerobic
bacterial culture at the end of each procedure.
Results—Test and control suction tips were contaminated
with bacteria during 30 of 44 (68%) procedures.
Staphylococcus spp were the predominant
bacteria in tips used during clean and clean-contaminated
surgeries. When surgery was performed on
clean-contaminated or contaminated wounds, prevalence
of isolation of other bacteria such as
Pseudomonas spp, Streptococcus spp, and
Escherichia coli from both test and control suction
tips was higher than for clean wounds. Mean time of
procedures during which both test and control suction
tips became contaminated was not significantly different
from time of procedures during which neither
tip became contaminated.
Conclusion and Clinical Relevance—Surgical suction
tips often become contaminated during standard
veterinary surgical procedures. The risk of wound
infection after surgery may be influenced by bacterial
contamination of surgical suction tips. (Am J Vet Res
Objective—To determine localization of tartrate-resistant
acid phosphatase (TRAP) and cathepsin K in ruptured
and healthy cranial cruciate ligaments (CCL) in
Animals—30 dogs with ruptured CCL, 8 aged dogs
without ruptured CCL, and 9 young dogs without ruptured
Procedure—The CCL was examined histologically
and cells containing TRAP and cathepsin K were identified
histochemically and immunohistochemically,
Results—Cathepsin K and TRAP were detected within
the same cells, principally within the epiligamentous
region and to a lesser extent in the core region
of ruptured CCL. Numbers of cells containing TRAP
and cathepsin K were significantly greater in ruptured
CCL, compared with CCL from young or aged dogs,
and numbers of such cells were greater in CCL from
aged dogs, compared with those of young dogs. In
aged dogs, small numbers of cells containing TRAP
and cathepsin K were seen in intact CCL associated
with ligament fascicles in which there was chondroid
transformation of ligament fibroblasts and disruption
of the extracellular matrix.
Conclusion and Clinical Relevance—Ruptured
CCL contain greater numbers of cells with the proteinases
TRAP and cathepsin K than CCL from
healthy, young, or aged dogs. Results suggest that
cell-signaling pathways that regulate expression of
these proteinases may form part of the mechanism
that leads to upregulation of collagenolytic ligament
remodeling and progressive structural failure of the
CCL over time. (Am J Vet Res 2002;63:1279–1284).
OBJECTIVE To evaluate the clinical features and pathological joint changes in dogs with erosive immune-mediated polyarthritis (IMPA).
DESIGN Retrospective case series.
ANIMALS 13 dogs with erosive IMPA and 66 dogs with nonerosive IMPA.
PROCEDURES The medical record database of a veterinary teaching hospital was reviewed to identify dogs with IMPA that were examined between October 2004 and December 2012. For each IMPA-affected dog, information extracted from the medical record included signalment, diagnostic test results, radiographic findings, and treatments administered. Dogs were classified as having erosive IMPA if review of radiographs revealed the presence of bone lysis in multiple joints, and descriptive data were generated for those dogs. All available direct smears of synovial fluid samples underwent cytologic evaluation. The synovial fluid total nucleated cell count and WBC differential count were estimated and compared between dogs with erosive IMPA and dogs with nonerosive IMPA.
RESULTS 13 of 79 (16%) dogs had erosive IMPA. Dogs with erosive IMPA had a mean ± SD age of 7.1 ± 2.4 years and body weight of 8.3 ± 3.4 kg (18.3 ± 7.5 lb). All 13 dogs had erosive lesions in their carpal joints. The estimated median synovial fluid lymphocyte count for dogs with erosive IMPA was significantly greater than that for dogs with nonerosive IMPA. All dogs received immunosuppressive therapy with leflunomide (n = 9), prednisone (3), or prednisone-azathioprine (1).
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated erosive IMPA most commonly affected the carpal joints of middle-aged small-breed dogs. Further genetic analyses and analysis of lymphocyte-subsets are warranted for dogs with erosive IMPA.
To determine the presentation, diagnosis, progression, and family risk of fibrotic myopathy, a disease with marked breed predisposition in the German Shepherd Dog (GSD).
41 dogs prospectively recruited to the University of Wisconsin-Madison Comparative Genetics and Orthopedic Laboratory between November 2019 to August 2022.
Medical records of dogs diagnosed with fibrotic myopathy were reviewed upon referral. The following data were recorded: sex, age, weight, regio interscapularis (withers) height, date of neutering, coat color and length, and age at fibrotic myopathy diagnosis. A pedigree was also obtained.
In the study population, breeds included 37 GSDs, a Belgian Malinois, a Belgian Malinois cross, and 2 dogs with a GSD phenotype and no pedigree. Mean age at fibrotic myopathy diagnosis was 5.9 ± 2.0 years, and duration of lameness before diagnosis was 5.6 months and ranged from 0.75 to 18 months. Males were overrepresented at 61% of the study population. Inherited familial risk for fibrotic myopathy in the GSD was supported by pedigree analysis.
This was the largest case series of fibrotic myopathy to date, providing a more comprehensive look at presentation and progression of the disease. The longer duration of lameness in bilaterally affected dogs likely represents disease progression rather than a more severe phenotype. Family history data support a genetic contribution to fibrotic myopathy, suggesting that further genetic investigation is warranted.