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  • Author or Editor: Peter D. Clegg x
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Case Description—3 horses with lameness localized to the proximal aspect of the metacarpus or metatarsus.

Clinical Findings—All horses had evidence of problems that originated from the proximal aspect of the suspensory ligament (PASL), including signs of pain on palpation, positive results of diagnostic nerve blocks, ultrasonographic detection of enlargement and diffuse areas of reduced echogenicity in the proximal region of insertion of the ligament, and radiographic detection of increased mineral opacity in the proximal aspect of the metacarpus or metatarsus. Desmitis of the PASL was diagnosed in each horse; however, conservative treatment failed to improve the lameness. The horses were taken to surgery for splitting of the PASL and osteostixis of the proximal aspect of the third metacarpal or metatarsal bone. At that time, the proximal aspect of the metacarpus or metatarsus was evaluated via computed tomography (CT), which identified new bone formation at the proximal aspect of the third metacarpal or metatarsal bone that had not already been identified.

Treatment and Outcome—In all horses, the newly formed bone was removed surgically under radiographic and CT guidance, and the splitting and osteostixis that had been planned were performed. After rehabilitation, all horses returned to full training at 6 months after surgery. All horses responded well to the surgical treatment and were sound 8 months afterward.

Clinical Relevance—Use of CT imaging should be considered in lame horses with pain associated with the proximal aspect of the third metacarpal or metatarsal bones that does not improve with conservative treatment.

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in Journal of the American Veterinary Medical Association


Objective—To compare the degree of mRNA expression for matrix metalloproteinases (MMPs), tissue inhibitors (TIMPs), and lysyl oxidase in myocardial samples from dogs with cardiac and systemic diseases and from healthy control dogs.

Sample—Myocardial samples from the atria, ventricles, and septum of 8 control dogs, 6 dogs with systemic diseases, 4 dogs with dilated cardiomyopathy (DCM), and 5 dogs with other cardiac diseases.

Procedures—Degrees of mRNA expression for MMP-1, -2, -3, -9, and -13; TIMP-1, -2, -3, and -4; and lysyl oxidase were measured via quantitative real-time PCR assay. Histologic examination of the hearts was performed to identify pathological changes.

Results—In myocardial samples from control dogs, only TIMP-3 and TIMP-4 mRNA expression was detected, with a significantly higher degree in male versus female dogs. In dogs with systemic and cardiac diseases, all investigated markers were expressed, with a significantly higher degree of mRNA expression than in control dogs. Furthermore, the degree of expression for MMP-2, TIMP-1, and TIMP-2 was significantly higher in dogs with DCM than in dogs with systemic diseases and cardiac diseases other than DCM. Expression was generally greater in atrial than in ventricular tissue for MMP-2, MMP-13, and lysyl oxidase in samples from dogs with atrial fibrillation.

Conclusions and Clinical Relevance—Degrees of myocardial MMP, TIMP, and lysyl oxidase mRNA expression were higher in dogs with cardiac and systemic diseases than in healthy dogs, suggesting that expression of these markers is a nonspecific consequence of end-stage diseases. Selective differences in the expression of some markers may reflect specific pathogenic mechanisms and may play a role in disease progression, morbidity and mortality rates, and treatment response.

Full access
in American Journal of Veterinary Research


Objective—To compare myocardial cytokine expression in dogs with naturally occurring cardiac or systemic diseases and dogs without cardiac or systemic diseases (control dogs)

Sample—Myocardial tissue samples from 7 systemic disease-affected dogs (SDDs), 7 cardiac disease-affected dogs (CDDs), and 8 control dogs.

Procedures—mRNA expression of interleukin (IL)-1, IL-2, IL-4, IL-6, IL-8, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, transforming growth factor (TGF)-β1, TGF-β2, TGF-β3, and growth differentiation factor-15 in myocardial tissue samples obtained from CDDs, SDDs, and control dogs were analyzed via quantitative PCR assays.

Results—In control dogs, only mRNA for TNF-α, TGF-β1, and TGF-β3 was detected; concentrations were significantly higher in male than in female dogs. In SDDs and CDDs, all cytokines, growth factors, and growth differentiation factor-15 were expressed. Compared with findings in SDDs, IL-1, IL-6, IL-8, IL-10, TNF-α, and IFN-γ expression was significantly increased in CDDs; specifically, IL-1, IL-8, TNF-α, TGF-β1, and TGF-β3 expression was increased in the atria and IL-8, IL-10, TNF-α, and IFN-γ expression was increased in the ventricles of CDDs.

Conclusions and Clinical Relevance—Data suggested that the alterations in cytokine expression in SDDs and CDDs, compared with control dog findings, were a result of inflammatory system activation. The differences in cytokine expression in atria and ventricles between SDDs and CDDs were suggestive of different remodeling processes. A better knowledge of myocardial involvement in SDDs and of immune regulation in CDDs might beneficially affect morbidity and mortality rates and provide new treatment approaches.

Full access
in American Journal of Veterinary Research


Objective—To assess 2 methods of RNA purification by use of different quality metrics and identify the most useful metric for quality assessment of RNA extracted from articular cartilage from dogs with osteoarthritis.

Sample Population—40 articular cartilage specimens from the femoral heads of 3 clinically normal dogs and 37 dogs with osteoarthritis.

Procedures—RNA was extracted from articular cartilage by 2 purification methods. Quality metrics of each sample were determined and recorded by use of a UV spectrophotometer (Spec I; to determine the 260 to 280 nm absorbance ratio [A260:A280 ratio]), a second UV spectrophotometer (Spec II; to determine A260:A280 and A260:A230 absorbance ratios), and a microfluidic capillary electrophoresis analyzer (to determine the ribosomal peak ratio [RR], degradation factor [DF], and RNA integrity number [RIN]). The RNA was extracted from affected (osteoarthritic) articular cartilage and assessed with the same quality metrics. Metric results were compared with visual analysis of the electropherogram to determine the most useful RNA quality metric.

Results—No differences in methods of RNA purification were determined by use of quality metrics. The RNA extracted from unaffected (normal) cartilage was of higher quality than that extracted from affected (osteoarthritic) cartilage, as determined by the RIN and Spec II A260:A230 ratio. The RIN and RR were the most sensitive metrics for determining RNA quality, whereas the DF was most specific. A significant proportion (32%) of RNA extracted from osteoarthritic articular cartilage specimens was determined as being of low quality.

Conclusions and Clinical Relevance—No single metric provided a completely sensitive and specific assessment of the quality of RNA recovered from articular cartilage.

Full access
in American Journal of Veterinary Research