Objective-To use computed tomography (CT) to provide a detailed description of elbow joint structures in clinically normal dogs. Animals-6 clinically normal adult mixed-breed dogs weighing 24 to 37 kg and one 12-month-old Labrador Retriever weighing 27 kg. Procedure-To perform CT of both elbow regions, dogs were anesthetized and placed in lateral recumbency. One- and 2-mm contiguous slices were obtained by use of a third generation computed tomographic scanner. Good resolution and anatomic detail were acquired from the computed tomographic images by use of a bone (window width, 3,500 Hounsfield units; window level, 500 Hounsfield units) and soft-tissue setting (window width, 400 Hounsfield units; window level, 66 Hounsfield units). After euthanasia, the forelimbs from the Labrador Retriever were removed and frozen in water at -18oC. Elbow joints were sectioned into approximately 1- mm-thick slab sections by use of an electric planer. Anatomic sections were photographed and compared with the corresponding computed tomographic images. Computed tomographic reconstructions of the elbow joint were created in sagittal and dorsal planes. Results-Structures on the computed tomographic images were matched with structures in the corresponding anatomic sections. The entire humeroradioulnar joint surface could be evaluated on the reconstructed images in the sagittal and dorsal plane. Conclusions and Clinical Relevance-Computed tomographic images provide full anatomic detail of the bony structures of the elbow joint in dogs. Muscles, large blood vessels, and nerves can also be evaluated. These results could be used as a basis for evaluation of computed tomographic images of the forelimbs of dogs with elbow joint injuries.

Objective-To evaluate the origin and degree of activity of nitric oxide (NO) and matrix metalloproteinase (MMP) in explants of cranial cruciate ligaments (CCLs) obtained from dogs and cultured with and without inflammatory activators. Sample Population-Tissue specimens obtained from 7 healthy adult Beagles that were (mean +/- SD) 4.5 +/- 0.5 years old and weighed 12.5 +/- 0.8 kg. Procedure-The CCLs were harvested immediately after dogs were euthanatized, and specimens were submitted for explant culture. Cultures were stimulated by incubation with a combination of interluekin-1, tumor necrosis factor-α, and lipopolysaccharide, or they were not stimulated. Culture supernatants were examined for production of NO nitrite-nitrate metabolites (NOts) and activity of MMP. Cultured specimens were evaluated by use of immunohistochemical analysis to detect activity of inducible NO synthase (iNOS). Results-All ligament explants produced measurable amounts of NOts. Stimulated cultures produced significantly more NOts after incubation for 24 and 48 hours, compared with nonstimulated cultures. Production of MMP in supernatants after incubation for 48 hours was significantly higher in stimulated cultures than in nonstimulated cultures. Cells with positive staining for iNOS were detected on all slides. Positively stained cells were predominantly chondroid metaplastic. There was a significant difference in intensity of cell staining between stimulated and nonstimulated cultures. Conclusion and Clinical Relevance—Explant cultures of intact CCLs obtained from dogs produce iNOS-induced NO. Stimulation of chondroid metaplastic cells in CCL of dogs by use of inflammatory activators can increase production of iNOS, NOts, and MMP.

Objective-To determine whether changes in amplitude of the reflex-evoked muscle action potential (REMP) elicited by noninvasive dental dolorimetry (electrical stimulation of the tooth pulp) in anesthetized dogs may be used to objectively evaluate the effectiveness of IV and intrathecal (IT) administration of morphine. Animals-6 male Beagles that were 2 to 6 years old. Procedure-Dogs were used in a crossover design with at least a 5-day washout period between treatments. Each dog received morphine, saline (0.9% NaCl) solution, and oxytocin via the IV and IT routes of administration; however, only results for morphine and saline treatments were reported here. Dogs were anesthetized and prepared for noninvasive dental dolorimetry. After IV or IT administration, electrical stimulation was applied to a tooth, and REMPs of the digastricus muscle were recorded at 5-minute intervals for 60 minutes. To determine differences in REMP amplitude between treatments, a linear regression line was fitted for each dog-treatment combination. Results-The IV administration of morphine significantly inhibited REMP amplitude, compared with IV administration of saline solution. Intrathecal administration of morphine significantly inhibited REMP amplitude, compared with IT administration of saline solution. Conclusions and Clinical Relevance-Noninvasive dental dolorimetry in anesthetized dogs has promise as a technique for use in evaluating the analgesic potential of drugs administered IV and IT through evaluation of their effect on REMP amplitude recorded for the digastricus muscle.

Objective-To develop a model for measuring rotary stability of the canine elbow joint and to evaluate the relative contribution of the anconeal process (AN), lateral collateral ligament (LCL), and medial collateral ligament (MCL). Sample Population-18 forelimbs from 12 canine cadavers. Procedure-Forelimbs were allocated to 3 experimental groups (6 forelimbs/group). Each intact forelimb was placed in extension at an angle of 135° and cycled 50 times from -16° (pronation) to +28° (supination) in a continuous manner at 2.0 Hz. Cycling was repeated following sectioning of the structure of interest (group 1, AN; group 2, LCL; and group 3, MCL). Torque at -12° (pronation) and +18° (supination) was measured for each intact and experimentally sectioned limb. A Student t test was performed to compare torque values obtained from intact verses experimentally sectioned limbs and for comparison with established criteria for differentiation of primary (≥ 33%), secondary (10 to 33%), and tertiary rotational stabilizers (< 10%). Results-In pronation, the AN was the only primary stabilizer (65%). For supination, the LCL was a primary stabilizer (48%), AN was a secondary stabilizer (24%), and MCL was a tertiary stabilizer (7%). Conclusions and Clinical Relevance-With the elbow joint in extension at an angle of 135°, the AN is a primary rotational stabilizer in pronation, and the LCL is a primary stabilizer in supination. Disruption of the AN or LCL may affect rotary range of motion or compromise stability of the elbow joint in dogs.

Objective-To assess the heritability of pancreatic acinar atrophy (PAA) in German Shepherd Dogs (GSDs) in the United States. Animals-135 GSDs belonging to 2 multigenerational pedigrees. Procedure-Two multigenerational pedigrees of GSDs with family members with PAA were identified. The clinical history of each GSD enrolled in the study was recorded, and serum samples for canine trypsinlike immunoreactivity (cTLI) analysis were collected from 102 dogs. Dogs with a serum cTLI concentration ≤ 2.0 µg/L were considered to have exocrine pancreatic insufficiency (EPI) and were assumed to have PAA. Results-Pedigree I consisted of 59 dogs and pedigree II of 76 dogs. Serum cTLI concentrations were measured in 48 dogs from pedigree I and 54 dogs from pedigree II. A total of 19 dogs (14.1%) were determined to have EPI, 9 in pedigree I (15.3%) and 10 in pedigree II (13.6%). Of the 19 dogs with EPI, 8 were male and 11 were female. Conclusion and Clinical Relevance-Evaluation of data by complex segregation analysis is strongly suggestive of an autosomal recessive mode of inheritance for EPI in GSDs in the United States.

Objective-To determine the ratio of ventral-to-dorsal transverse diameters between the wings of the sacrum on ventrodorsal radiographic views of the pelvis in large dogs and to validate the reliability of this morphometric analysis for functional interpretation. Sample Population-Pelvic specimens from 40 large-breed dogs and radiographs of 113 large-breed dogs. Procedure-In an anatomic and radiographic evaluation, the transverse dorsal diameter (TVDS) and transverse ventral diameter (TVV) between the wings of the sacrum were evaluated in sacrum specimens and on corresponding radiographs of the pelvis and sacrum. The ratio between TVV and TVDS (VD ratio) was calculated. Intraobserver reliability was determined by calculation of the coefficient of variation. In a retrospective radiographic evaluation, the VD ratio was determined in Rottweilers, Golden Retrievers, and German Shepherd Dogs. Correlations between VD ratio and breed, age, and sex were tested. Results-The VD ratio was significantly higher in Rottweilers than in Golden Retrievers and German Shepherd Dogs, denoting an oblique alignment of the sacral wings in Rottweilers (ie, the dorsal aspects of the sacral wings were located more medially than the ventral aspects) and an almost sagittal alignment in the other breeds. The VD ratio was significantly associated with age but not with sex. Conclusion and Clinical Relevance-Sagittal alignment of the wings of the sacrum is considered to be biomechanically less efficient. These results provide a basis for further studies to evaluate radiographic assessment of the sacroiliac joints similar to the evaluation for hip dysplasia.

Objective-To develop a laparoscopic-assisted technique for cystopexy in dogs. Animals-8 healthy male dogs, 7 healthy female dogs, and 3 client-owned dogs with retroflexion of the urinary bladder secondary to perineal herniation. Procedure-Dogs were anesthetized, and positive pressure ventilation was provided. In the healthy male dogs, the serosal surface of the bladder was sutured to the abdominal wall. In the healthy female dogs, the serosa and muscular layer of the bladder were incised and sutured to the aponeurosis of the external and internal abdominal oblique muscles. Dogs were monitored daily for 30 days after surgery. Results-All dogs recovered rapidly after surgery and voided normally. In the female dogs, results of urodynamic (leak point pressure and urethral pressure profilometry) and contrast radiographic studies performed 30 days after surgery were similar to results obtained before surgery. Cystopexy was successful in all 3 client-owned dogs, but 1 of these dogs was subsequently euthanatized because of leakage from a colopexy performed at the same time as the cystopexy. Conclusion and Clinical Relevance-The laparoscopic-assisted cystopexy technique was quick, easy to perform, and not associated with urinary tract infection or abnormalities of urination.

Objective-To determine whether Haemobartonella canis and Mycoplasma haemofelis (formerly known as H felis [large form]) can be differentiated by use of comparative analysis of gene sequences. Sample Population-Blood samples obtained from 3 dogs infected with H canis and 2 cats infected with M haemofelis. Procedure-The partial 16S rDNA and ribonuclease P RNA (RNase P) genes were amplified, cloned, and sequenced in blood samples obtained from H canis-infected dogs and M haemofelis-infected cats. The DNA sequences were subjected to comparative analysis. Results-The 16S rDNA sequences of H canis and M haemofelis were nearly identical (homology of 99.3 to 99.7%). In contrast, RNase P gene sequences had a lower degree of sequence homology between the 2 organisms (94.3 to 95.5%). Conclusions and Clinical Relevance-Haemobartonella canis and M haemofelis are not identical organisms. Molecular differentiation of H canis and M haemofelis is more clearly evident by use of comparative analysis of RNase P gene sequences than by comparative analysis of 16S rDNA gene sequences.

Objective-To determine tracheal mucociliary clearance rate (TMCCR) by use of a standard protocol in healthy anesthetized cats and to determine the effect of theophylline on TMCCR in healthy anesthetized cats. Animals-6 healthy cats. Procedure-Cats were anesthetized with propofol, and a droplet of the radiopharmaceutical technetium Tc 99m macroaggregated albumin was placed endoscopically at the carina. Dynamic acquisition scintigraphic imaging was performed, using the larynx as the end point. The TMCCR was determined by measuring the distance the droplet traveled by frame rate. Each cat was imaged 6 times as follows: 3 times following placebo administration and 3 times following the administration of sustained release theophylline (25 mg/kg, PO). Serum theophylline concentrations were assessed during imaging to ensure therapeutic concentrations. Results-The TMCCR in healthy adult cats anesthetized with propofol was 22.2 +/- 2.8 mm/min. Tracheal mucociliary clearance rate in cats receiving theophylline was 21.8 +/- 3.5 mm/min. Theophylline administration did not significantly alter TMCCR. Conclusion and Clinical Relevance-Theophylline has been shown to increase TMCCR in humans and dogs. In our study, we determined TMCCR in healthy anesthetized cats and found that it was not accelerated by the administration of theophylline.

Objective-To determine total glutathione (GSH) and glutathione disulfide (GSSG) concentrations in liver tissues from dogs and cats with spontaneous liver disease. Sample Population-Liver biopsy specimens from 63 dogs and 20 cats with liver disease and 12 healthy dogs and 15 healthy cats. Procedure-GSH was measured by use of an enzymatic method; GSSG was measured after 2-vinylpyridine extraction of reduced GSH. Concentrations were expressed by use of wet liver weight and concentration of tissue protein and DNA. Results-Disorders included necroinflammatory liver diseases (24 dogs, 10 cats), extrahepatic bile duct obstruction (8 dogs, 3 cats), vacuolar hepatopathy (16 dogs), hepatic lipidosis (4 cats), portosystemic vascular anomalies (15 dogs), and hepatic lymphosarcoma (3 cats). Significantly higher liver GSH and protein concentrations and a lower tissue DNA concentration and ratio of reduced GSH-to-GSSG were found in healthy cats, compared with healthy dogs. Of 63 dogs and 20 cats with liver disease, 22 and 14 had low liver concentrations of GSH (µmol) per gram of tissue; 10 and 10 had low liver concentrations of GSH (nmol) per milligram of tissue protein; and 26 and 18 had low liver concentrations of GSH (nmol) per microgram of tissue DNA, respectively. Low liver tissue concentrations of GSH were found in cats with necroinflammatory liver disease and hepatic lipidosis. Low liver concentrations of GSH per microgram of tissue DNA were found in dogs with necroinflammatory liver disease and cats with necroinflammatory liver disease, extrahepatic bile duct occlusion, and hepatic lipidosis. Conclusions and Clinical Relevance-Low GSH values are common in necroinflammatory liver disorders, extrahepatic bile duct occlusion, and feline hepatic lipidosis. Cats may have higher risk than dogs for low liver GSH concentrations.