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  • Author or Editor: Eithne J. Comerford x
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Abstract

Objective—To assess different components of the extracellular matrix with regard to their thermal properties, composition, and turnover in ruptured cranial cruciate ligaments (CCLs) of dogs, compared with components of intact CCLs from a breed predisposed to CCL failure.

Sample Population—Ruptured CCLs obtained from 8 dogs of breeds predisposed to ruptured CCLs and intact CCLs from 12 cadaveric Labrador Retrievers.

Procedure—Ruptured and intact CCLs were analyzed for water content; collagen content and collagen cross-links were evaluated via hydroxyproline and amino-acid analyses, respectively. Glycosaminoglycan (GAG) content was analyzed via dimethylmethylene blue and uronic acid assays. Matrix metalloproteinases (MMPs)-2 and -9 and the tissue inhibitors of metalloproteinases (TIMPs)-1 and -2 were detected via gelatin SDS-PAGE zymography and reverse gelatin zymography. Thermal analysis of ligaments was performed by use of differential scanning calorimetry.

Results—Ruptured CCLs had significantly higher lamounts of immature cross-links, total and sulfated GAGs, and water content, compared with that of the intact ligaments. Compared with intact CCLs, concentration of pro–MMP-2 was significantly higher in ruptured CCLs; the maximum temperature of collagen denaturation was significantly lower in the ruptured CCLs.

Conclusions and Clinical Relevance—The extracellular matrix of ruptured CCLs had an increased matrix turnover indicated by increased collagen and GAG synthesis, compared with that of intact CCLs. Although the extracellular matrix changes may have occurred before ligament rupture, it is possible that these observed changes may be part of a reparative process after rupture. (Am J Vet Res 2004;65:1136–1141)

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in American Journal of Veterinary Research

Abstract

Objective—To quantify angular excursions; net joint moments; and powers across the stifle, tarsal, and metatarsophalangeal (MTP) joints in Labrador Retrievers and Greyhounds and investigate differences in joint mechanics between these 2 breeds of dogs.

Animals—12 clinically normal dogs (6 Greyhounds and 6 Labrador Retrievers) with no history of hind limb lameness.

Procedure—Small retroreflective markers were applied to the skin over the pelvic limb joints, and a 4- camera kinematic system captured data at 200 Hz in tandem with force platform data while the dogs trotted on a runway. Breed-specific morphometric data were combined with kinematic and force data in an inverse-dynamics solution for stance-phase net joint moments and powers at the stifle, tarsal, and MTP joints.

Results—There were gross differences in kinematic patterns between Greyhounds and Labradors. At the stifle and tarsal joints, moment and power patterns were similar in shape, but amplitudes were larger for the Greyhounds. The MTP joint was a net absorber of energy, and this was greater in the Greyhounds. Greyhounds had a positive phase across the stifle, tarsal, and MTP joints at the end of stance for an active push-off, whereas for the Labrador Retrievers, the only positive phase was across the tarsus, and this was small, compared with values for the Greyhounds.

Conclusions and Clinical Relevance—Gross differences in pelvic limb mechanics are evident between Greyhounds and Labrador Retrievers. Joint kinetics in specific dogs should be compared against breed-specific patterns. (Am J Vet Res 2005;66:1563–1571)

Full access
in American Journal of Veterinary Research