Mannheimia haemolytica and Histophilus somni are frequently isolated from diseased cattle with bovine respiratory disease (BRD). They compromise animal lung function and the immune responses generated are not sufficient to limit infection. Identification of specific immunogenic antigens for vaccine development represents a great challenge. Immunogenic proteins were identified by immunoproteomic approach with sera from cattle immunized with a commercial cellular vaccine of M. haemolytica and H. somni. Proteins of M. haemolytica were identified as solute ABC transporter, iron-binding protein, and hypothetical protein of capsular biosynthesis. Histophilus somni proteins correspond to porin, amino acid ABC transporter, hypothetical outer membrane protein, cysteine synthase, and outer membrane protein P6. Although these antigens share strong similarities with other proteins from animal pathogens, the ABC system proteins have been associated with virulence and these proteins could be considered as potential vaccine candidates for BRD.

Objective: To determine the effects of exercise on the distribution and pharmacokinetics of technetium Tc 99m medronate (99mTc-MDP) following intra-articular (IA) injection in horses. Animals: 5 horses. Procedures: 1 antebrachiocarpal joint (ACJ)/horse was assigned to the exercised group (n = 5), and the contralateral ACJ was evaluated in the nonexercised group (5) after a minimum washout period of 7 days. Following IA injection of 99mTc-MDP (148 MBq), blood and scintigraphic images of the carpus were obtained at 5, 10, 15, 20, 25, 30, 45, 60, 90, 120, 240, 360, 480, 600, 720, and 1,440 minutes. Plasma and scintigraphic radioactivity were determined over time, and pharmacokinetic parameters were generated via noncompartmental and compartmental analyses. Each horse was monitored via physical and lameness examination and ACJ synovial fluid analysis before injection and at days 1, 2, 3, and 7. Results: Lameness was not observed. Mean ± SD synovial fluid WBC count increased at day 1 (exercised, 721 ± 234 cells/μL; nonexercised, 948 ± 223 cells/μL), but returned to baseline at days 3 and 7 Mean time to maximum plasma radioactivity was earlier in the exercised group (16.00 ± 2.35 minutes) than the nonexercised group (43.75 ± 3.64 minutes). Linear regression of the scintigraphic radioactivity-time curves revealed a greater negative slope in the exercised group within the first 25 minutes. There was no difference in absorption or elimination rate constants in a 2-compartment model. Conclusions and Clinical Relevance: IA injection of 99mTc-MDP was safe and effective for evaluating synovial solute distribution. Exercise significantly increased early transfer of 99mTc-MDP from the ACJ into plasma, although absorption and elimination rate constants were not affected. Exercise may affect synovial clearance and withdrawal times of medications administered IA.

Objective—To determine the association between urine osmolality and specific gravity (USG) in dogs and to evaluate the effect of commonly measured urine solutes on that association. Animals—60 dogs evaluated by an internal medicine service. Procedures—From each dog, urine was obtained by cystocentesis and USG was determined with a refractometer. The sample was divided, and one aliquot was sent to a diagnostic laboratory for urinalysis and the other was frozen at −80°C until osmolality was determined. Urine samples were thawed and osmolality was measured in duplicate with a freezing-point depression osmometer. The correlation between mean urine osmolality and USG was determined; the effect of pH, proteinuria, glucosuria, ketonuria, bilirubinuria, and hemoglobinuria on this relationship was investigated with multiple regression analysis. Results—The Pearson correlation coefficient between urine osmolality and USG was 0.87. The final multivariable regression model for urine osmolality included USG and the presence of ketones; ketonuria had a small negative association with urine osmolality. Conclusions and Clinical Relevance—Results indicated a strong linear correlation between osmolality and USG in urine samples obtained from dogs with various pathological conditions, and ketonuria had a small negative effect on that correlation.

Objective: To characterize mucosal gene expression in dogs with chronic enteropathy (CE). Animals: 18 dogs with CE and 6 healthy control dogs. Procedures: Small intestinal mucosal biopsy specimens were endoscopically obtained from dogs. Disease severity in dogs with CE was determined via inflammatory bowel index scores and histologic grading of biopsy specimens. Total RNA was extracted from biopsy specimens and microchip array analysis (approx 43,000 probe sets) and quantitative reverse transcriptase PCR assays were performed. Results: 1,875 genes were differentially expressed between dogs with CE and healthy control dogs; 1,582 (85%) genes were downregulated in dogs with CE, including neurotensin, fatty acid–binding protein 6, fatty acid synthase, aldehyde dehydrogenase 1 family member B1, metallothionein, and claudin 8, whereas few genes were upregulated in dogs with CE, including genes encoding products involved in extracellular matrix degradation (matrix metallopeptidases 1, 3, and 13), inflammation (tumor necrosis factor, interleukin-8, peroxisome proliferator–activated receptor γ, and S100 calcium-binding protein G), iron transport (solute carrier family 40 member 1), and immunity (CD96 and carcinoembryonic antigen–related cell adhesion molecule [CEACAM] 18). Dogs with CE and protein-losing enteropathy had the greatest number of differentially expressed genes. Results of quantitative reverse transcriptase PCR assay for select genes were similar to those for microchip array analysis. Conclusions and Clinical Relevance: Expression of genes encoding products regulating mucosal inflammation was altered in dogs with CE and varied with disease severity. Impact for Human Medicine: Molecular pathogenesis of CE in dogs may be similar to that in humans with inflammatory bowel disease.

Objective-To evaluate the effect of prolonged water exposure on tissue mass and solutes of outer and inner layers of the stratum medium, sole, frog, and the stratum medium (SMZA) zona alba layer of horses' hooves. Specimen Population-10 hooves from 10 horses without foot abnormalities. Procedure-Hoof wall tissue specimens were obtained and immersed for 10 days in distilled deionized water. Serial changes in mass were recorded during the immersion period. Subsequently, osmolarity and Na+, K+, Cl-, and protein concentrations of the immersion solution were quantified. Results-Fully cornified outer hoof wall, sole, and frog epidermal structures increased in mass, whereas the SMZA lost mass when immersed in water. All hoof structures had a variable loss of crystalloids during immersion, but none of the specimens lost proteins. The frog epidermis was distinct in that total solute lost during immersion could not be ascribed to Na+, K+, and Cl-. Conclusions and Clinical Relevance-Data support a 2-compartment model for the fully cornified outer stratum medium, frog, and sole that permits the exchange of crystalloids, but not proteins, across the cell membrane and infers that topical agents containing proteins cannot benefit the hoof. The unique osmotic behavior of the SMZA relative to other hoof structures suggests the hypothesis that it is composed of transitional epithelial cells. The solutes lost from frog epithelium are interpreted to reflect its unique lipid composition.