Objective—To assess whether the Pfirrmann system for grading lumbar intervertebral disk (IVD) degeneration in humans can also be used in dogs. Animals—202 dogs. Procedures—Magnetic resonance imaging was used to obtain images of vertebral segments from dogs, which were reviewed separately by 3 observers who graded the extent of degeneration in each visible IVD by use of the Pfirrmann classification system used for grading lumbar IVD degeneration in humans. Grading was validated against 2 factors associated with the extent of disk degeneration: type of dog (chondrodystrophic or nonchondrodystrophic breeds) and age. Results—Interobserver and intraobserver agreement for Pfirrmann grading of IVD degeneration were good (κ scores, 0.81 to 0.93). An increase in the extent of disk degeneration was positively correlated with increases in age and with chondrodystrophic breed. Conclusions and Clinical Relevance—The Pfirrmann system was reliably used to grade IVD degeneration in dogs of various breeds and ages. An increase in the extent of IVD degeneration was positively correlated with increases in age and with chondrodystrophic-type dogs.

Objective—To investigate the effects of acepromazine maleate and morphine on aqueous tear production before, during, and after sevoflurane anesthesia in dogs. Animals—6 mixed-breed dogs. Procedures—In a Latin square study design, dogs underwent IM administration of morphine (1 mg/kg), acepromazine (0.05 mg/kg), or saline (0.9% NaCl) solution (0.05 mL/kg), followed by induction and maintenance of anesthesia with sevoflurane for 30 minutes. The protocol was repeated until all dogs had received all treatments, with a minimum of 7 days between anesthetic episodes. Aqueous tear production was measured via Schirmer tear test I before treatment (baseline); before anesthetic induction; 5, 10, 20, and 30 minutes after anesthetic induction; immediately once dogs recovered from anesthesia; and 2 and 10 hours after recovery. Results—Aqueous tear production for all treatments was significantly lower 10, 20, and 30 minutes (but not 5 minutes) after anesthetic induction than at baseline, before anesthetic induction, at recovery, and 2 and 10 hours after recovery. Aqueous tear production was significantly higher after saline solution administration than after morphine administration at the preinduction measurement point and 2 hours after recovery. No other differences were detected among the 3 treatments. Conclusions and Clinical Relevance—Aqueous tear production after anesthesia did not differ significantly from baseline values after any treatment following 30 minutes of sevoflurane anesthesia, suggesting premedication with morphine or acepromazine does not contribute to a decrease in lacrimation in these circumstances.

Objective—To evaluate the diagnostic value of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentrations in Doberman Pinschers in various stages of dilated cardiomyopathy (DCM). Animals—328 Doberman Pinschers. Procedures—Staging of DCM was determined via analysis of results of physical examinations, 24-hour ambulatory ECG (Holter) recordings, and echocardiographic evaluations. Plasma samples for NT-proBNP assays were obtained at each examination. Concentrations of NT-proBNP were measured in 337 samples obtained from 196 healthy Doberman Pinschers (control dogs) and in 195 samples obtained from 132 Doberman Pinschers in various stages of DCM. These included dogs that had ventricular premature contractions (VPCs; 79 samples), echocardiographic changes (23 samples), or both (51 samples); 16 samples were from dogs with overt DCM, and 26 were from dogs that were considered normal during initial examination but developed DCM within 1.5 years after this assessment. Receiver operating characteristic curves were analyzed to determine sensitivity and specificity of NT-proBNP concentrations for detection of DCM. Results—NT-proBNP concentrations in dogs that had or developed DCM were significantly higher than those of control dogs. Sensitivity and specificity of NT-proBNP concentrations (cutoff value, > 400 pmol/L) to detect all stages of DCM were 81.1 % and 75.0%, respectively; sensitivity was 90.0% and specificity was 75.0% to predict echocardiographic changes. Specificity to detect echocardiographic changes was 90.4% at a cutoff value of 550 pmol/L. Conclusions and Clinical Relevance—Plasma concentrations of NT-proBNP were increased in dogs with DCM and in apparently healthy dogs that developed DCM within 1.5 years after samples were obtained, compared with concentrations in control dogs.

Objective—To develop and determine the feasibility of a novel minimally invasive technique for percutaneous catheterization and embolization of the thoracic duct (PCETD) in dogs and to determine thoricic duct TD pressure at rest and during short-term balloon occlusion of the cranial vena cava (CrVC). Animals—Fifteen 7- to 11-month-old healthy mixed-breed dogs. Procedures—Efferent intestinal lymphangiography was performed, and the cisterna chyli was punctured with a trochar needle percutaneously under fluoroscopic guidance. When access was successful, a guide wire was directed into the TD through the needle and a vascular access sheath was advanced over the guide wire. Thoracic duct pressure was measured at rest and during acute balloon occlusion of the CrVC. The TD was then embolized cranial to the diaphragm with a combination of microcoils and cyanoacrylate or ethylene vinyl alcohol. Results—Successful puncture of the cisterna chyli with advancement of a wire into the TD was possible in 9 of 15 dogs, but successful catheterization was possible in only 5 of 9 dogs. Acute balloon occlusion of the CrVC led to a substantial TD pressure increase in 4 of 4 dogs, and embolization of the TD was successful in 4 of 4 dogs. Conclusions and Clinical Relevance—PCETD can successfully be performed in healthy dogs; however, this minimally invasive technique cannot currently be recommended for routine treatment of chylothorax, in part because of the technically demanding nature of the procedure. An increase in jugular venous pressure led to an increase in TD pressure, potentially predisposing some dogs to developing chylothorax.

Objective: To compare temporospatial variables (TSVs) and kinetic variables (KVs) for fore-limbs and hind limbs of small and large dogs of various breeds during walking and to determine associations among body weight (BW), TSVs, and KVs in these groups. Animals: 12 adult dogs with no evidence of lameness. Procedures: Dogs (grouped according to BW as small [< 10 kg; n = 6] or large [> 25 kg; 6]) were walked in a straight line at their preferred velocity on a wooden platform with an embedded pressure-sensing walkway. Five valid trials were analyzed for each dog; mean TSVs and KVs were determined for each group. The TSVs and KVs for forelimbs and hind limbs were compared between groups, and correlations among BW, TSVs, and KVs were determined. Results: Small dogs had significantly smaller TSVs and KVs than did large dogs. Temporal variables of small dogs and absolute vertical force variables of small and large dogs increased as BW increased. However, normalized peak vertical force and weight distribution values among the 4 limbs were similar between groups. Conclusions and Clinical Relevance: Substantial similarities and differences were detected in gait characteristics between small and large dogs. Results indicated TSVs and KVs can be used for comparison of the walking gait between dogs or for comparison of variables between limbs in an individual dog. Use of the pressure-sensing walkway is a simple method for acquisition of TSVs and KVs for large and small dogs.

Objective—To evaluate symmetry of the hind limbs in orthopedically normal trotting dogs. Animals—19 orthopedically normal Labrador Retrievers with no history of lameness. Procedures—Retroreflective markers were applied to the hind limb joints, and a 4-camera kinematic system captured positional data at 200 Hz in tandem with force platform data collection while the dogs trotted. Morphometric data were combined with kinematic and force data in an inverse dynamics method to calculate net joint moments and powers at the joints as well as total support moment for each limb. Dogs were identified as right or left dominant when their total support moment was > 10% asymmetric between sides. Results—10 of the 19 dogs were mechanically dominant in the right hind limb as determined by their total support moments. One dog was left dominant, and the remaining 8 were symmetric. Right-dominant dogs had larger net joint moments at the right hip, tarsal, and metatarsophalangeal joints and a smaller moment at the right stifle joint, compared with values for the left hind limb. The 1 left-dominant dog had the exact opposite findings. Hip and stifle joint moments and powers varied between limbs of the right-dominant and left-dominant groups in the timing of their transition from negative to positive, and power amplitudes varied at the hip, tarsal, and metatarsophalangeal joints but not the stifle joint. Conclusions and Clinical Relevance—Sound trotting dogs can have asymmetries in limb and joint mechanics. These natural mechanical asymmetries should be taken into account when considering models to evaluate stresses at joints and when considering surgery for cruciate ligament rupture.

Objective--To evaluate 5 commercially available ELISAs for determination of leptin concentrations in serum samples from dogs. Sample Population--Serum samples from overweight-obese and thin–ideal weight clientowned dogs. Procedures--Serum samples with high and low leptin concentrations (n = 7 samples each) were used for validation of the assays. Intra- and interassay precision, linearity under dilution, spiking recovery, and limit of quantification were determined. In addition, leptin concentrations in thin–ideal weight (n = 8) and overweight-obese (37) dogs were quantified. Results--Use of 2 of the 5 ELISAs (A and B) revealed reactivity with canine leptin. Intra-and interassay coefficients of variation were < 6.1% and 76%, respectively, for assay A and 14.0% and 13.7%, respectively, for assay B. In assays A and B, dilutions of canine serum pools were used to determine linear regression equations. Recoveries were 77% to 101% for assay A and 67% to 125% for assay B. Significant differences in leptin concentrations between thin–ideal weight and overweight-obese dogs were detected only when analyzed with assay A. Conclusions and Clinical Relevance--Among 5 leptin ELISAs evaluated, a canine-specific leptin ELISA had adequate precision, linearity, and ability to discriminate between high and low leptin concentrations corresponding to overweight-obese and thin–ideal weight dogs, respectively.

Among grow-to-finish pigs from 10 herds in Alberta and Saskatchewan, 23 (16%) of 144 fecal samples were culture-positive and 40 (28%) of 144 pigs were seropositive for Salmonella. With a Bayesian model specifying dependence between the 2 tests, the sensitivity (Se) of culture and real-time polymerase chain reaction (RT-PCR) was 79% to 86%, depending on the cut-off value for the enzyme-linked immunosorbent assay (ELISA). Culture specificity (Sp) was assumed to be 100%; RT-PCR Sp was found to be 94%. The ELISA Se was 76% and 51% at optical density cut-off values ≥ 20% and ≥ 40%, respectively; the Sp was 94% at each cut-off value. The model showed some sensitivity to ELISA prior information, the ELISA Se being approximately 8% lower when informative prior information was specified in the model. When there was no adjustment for dependence between culture and RT-PCR, the posterior estimates for both culture and RT-PCR Se were 11% higher than with the conditional-dependence model and had considerably narrower probability intervals, which suggests that correlation between culture and PCR is important and should be adjusted for in future studies.

Objective—To isolate and characterize bacteriophages with strong in vitro lytic activity against various pathogenic Pseudomonas aeruginosa strains isolated from dogs with ocular infections. Sample—26 genetically distinct P aeruginosa isolates. Procedures—P aeruginosa strains were derived from dogs with naturally acquired ulcerative keratitis. From a large-scale screening for bacteriophages with potential therapeutic benefit against canine ocular infections, 2 bacteriophages (P2S2 and P5U5) were selected; host ranges were determined, and phage nucleic acid type and genetic profile were identified via enzymatic digestion. Electron microscopy was used to characterize bacteriophage ultrastructure. Bacteriophage temperature and pH stabilities were assessed by use of double-layer agar overlay titration. A cocultivation assay was used to evaluate the effect of the bacteriophages on bacterial host growth. Results—P5U5 was active against all P aeruginosa isolates, whereas P2S2 formed lytic plaques on plates of 21 (80.8%) isolates. For each bacteriophage, the genomic nucleic acid was DNA; each was genetically distinct. Ultrastructurally, P2S2 and P5U5 appeared likely to belong to the Podoviridae and Siphoviridae families, respectively. The bacteriophages were stable within a pH range of 4 to 12; however, titers of both bacteriophages decreased following heating for 10 to 50 minutes at 45° or 60°C. Growth of each P aeruginosa isolate was significantly inhibited in coculture with P2S2 or P5U5; the dose response was related to the plaque-forming unit-to-CFU ratios. Conclusions and Clinical Relevance—Bacteriophages P2S2 and P5U5 appear to be good candidates for phage treatment of infection caused by pathogenic P aeruginosa in dogs.

Objective—To examine the changes in monocarboxylate transporter (MCT) 1 and MCT4 content and in indicators of energy metabolism in the gluteus medius muscle (GMM) of Thoroughbreds during growth. Animals—6 Thoroughbreds (3 males and 3 females). Procedures—Samples of GMM were obtained when horses were 2, 6, 12, and 24 months old. Muscle proteins were separated via SDS-PAGE; amounts of MCT1 and MCT4 and peroxisome proliferator-activated receptor-γ coactivator-1α content were determined by use of western blotting. Muscle activities of phosphofructokinase and citrate synthase were measured biochemically; lactate dehydrogenase isoenzymes were separated by agarose gel electrophoresis and quantified. Results—Compared with findings when horses were 2 months old, MCT1 protein content in GMM samples obtained when the horses were 24 months old was significantly higher; however, MCT4 protein content remained unchanged throughout the study period. Peroxisome proliferator-activated receptor-γ coactivator-1α content was significantly increased at 24 months of age and citrate synthase activity was increased at 6 and 24 months of age, compared with findings at 2 months. Phosphofructokinase activity remained unaltered during growth. The percentage contributions of lactate dehydrogenase 1 and 2 isoenzymes to the total amount of all 5 isoenzymes at 12 and 24 months of age were significantly higher than those at 2 months of age. Conclusions and Clinical Relevance—Changes in protein contents of MCTs and the lactate dehydrogenase isoenzyme profile in GMM samples suggested that lactate usage capacity increases with growth and is accompanied by an increase in the oxidative capacity in Thoroughbreds.