OBJECTIVE To evaluate pharmacokinetic and pharmacodynamic characteristics of 3 doses of tapentadol hydrochloride orally administered in dogs. ANIMALS 6 healthy adult mixed-breed dogs. PROCEDURES In a prospective, randomized crossover study, dogs were assigned to receive each of 3 doses of tapentadol (10, 20, and 30 mg/kg, PO); there was a 1-week washout period between subsequent administrations. Plasma concentrations and physiologic variables were measured for 24 hours. Samples were analyzed by use of high-performance liquid chromatography–tandem mass spectrometry. RESULTS Tapentadol was rapidly absorbed after oral administration. Mean maximum plasma concentrations after 10, 20, and 30 mg/kg were 10.2, 19.7, and 31 ng/mL, respectively. Geometric mean plasma half-life of the terminal phase after tapentadol administration at 10, 20, and 30 mg/kg was 3.5 hours (range, 2.7 to 4.5 hours), 3.7 hours (range, 3.1 to 4.0 hours), and 3.7 hours (range, 2.8 to 6.5 hours), respectively. Tapentadol and its 3 quantified metabolites (tapentadol sulfate, tapentadol-O-glucuronide, and desmethyltapentadol) were detected in all dogs and constituted 0.16%, 2.8%, 97%, and 0.04% of the total area under the concentration-time curve (AUC), respectively. Plasma AUCs for tapentadol, tapentadol sulfate, and tapentadol-O-glucuronide increased in a dose-dependent manner. Desmethyltapentadol AUC did not increase in a linear manner at the 30-mg/kg dose. Sedation scores and heart and respiratory rates were not significantly affected by dose or time after administration. CONCLUSIONS AND CLINICAL RELEVANCE Oral administration of tapentadol was tolerated well, and the drug was rapidly absorbed. Adverse events were not apparent in any dogs at any doses in this study.

Salmonella enterica serovar Typhimurium has a wide host range and is capable of causing infections ranging from severe gastroenteritis to systemic infection in humans. To determine if attenuated S. Typhimurium strains can serve as safe and effective oral vaccines to prevent typhoid fever, the biologic characteristics of crp and sipB deletion mutants were evaluated. Previous studies had found that the crp and sipB genes are related to Salmonella pathogenicity. In this study, cytotoxicity, protective efficacy, and immune responses of the host were analyzed. Our previous data had shown a significance decrease in virulence for the crp and sipB mutants compared with a wild-type strain. The current study confirmed this finding in HeLa cells and showed that the crp mutant was significantly less cytotoxic (P < 0.05) than the sipB mutant. Mice vaccinated with the crp mutant showed significantly better protection after challenge with the wild-type strain (P < 0.05) and significantly greater responses in serum IgG (P < 0.01) and secretory IgA (P < 0.05) compared with the mice vaccinated with the sipB mutant (P < 0.05). Our results indicate that the crp mutant has the potential to be a vaccine candidate and is safe in mice.

The objective of this study was to examine the effects of immunosuppressive prednisolone therapy on pancreatic tissue and the concentration of serum canine pancreatic lipase immunoreactivity (cPLI) in healthy dogs. Six healthy beagle dogs were subcutaneously administered an immunosuppressive dose of prednisolone [4 mg/kg body weight (BW)] once daily for either 2 or 3 weeks. Serum cPLI concentration was measured before and after treatment. Ultrasonographic examination of the pancreas and laparoscopic biopsy and histopathological examination of the right pancreatic lobe and the liver were also conducted before and after treatment. The expression of pancreatic lipase messenger ribonucleic acid (mRNA) in the pancreas and liver was examined by polymerase chain reaction (PCR). Although the serum cPLI concentration was significantly higher on day 14 and on the day of the second laparoscopy than before treatment, it was classified as normal (≤ 200 μg/L) in 5 dogs and as abnormal (≥ 400 μg/L) in only 1 dog. None of the 6 dogs showed clinical signs of pancreatitis during the study period. After treatment, ultrasonographic examination of the pancreas showed no changes except for a hypoechoic pancreas in 1 dog. Histopathological examination of the right pancreatic lobe in all dogs showed no evidence of pancreatitis after treatment. Pancreatic lipase mRNA expression was detected in the pancreas, but not in the liver, before and after treatment. The administration of 4 mg/kg BW per day of prednisolone for 2 or 3 weeks increased the serum cPLI concentration without clinical signs of pancreatitis, although an abnormal cPLI concentration (≥ 400 μg/L) was observed in only 1 dog. No ultrasonographic or histological evidence of pancreatitis was observed in any of the dogs.

OBJECTIVE To evaluate the diagnostic yield of dental radiography (Rad method) and cone-beam CT (CBCT) methods for the identification of 31 predefined dental disorders in brachycephalic dogs. ANIMALS 19 client-owned brachycephalic dogs admitted for evaluation and treatment of dental disease. PROCEDURES 31 predefined dental disorders were evaluated separately and scored by use of dental radiography and 3 CBCT software modules (serial CBCT slices and custom cross sections, tridimensional rendering, and reconstructed panoramic views). A qualitative scoring system was used. Dental disorders were grouped into 10 categories for statistical analysis. Point of reference for presence or absence of a dental disorder was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ2 test of marginal homogeneity of paired data. RESULTS When all 3 CBCT methods were used in combination, the diagnostic yield of CBCT was significantly higher than that of dental radiography for 4 of 10 categories (abnormal eruption, abnormally shaped roots, periodontitis, and tooth resorption) and higher, although not significantly so, for all categories, except for 1 (loss of tooth integrity). CONCLUSIONS AND CLINICAL RELEVANCE CBCT provided more detailed information than did dental radiography. Therefore, CBCT would be better suited for use in diagnosing dental disorders in brachycephalic dogs.

OBJECTIVE To use high-field and low-field MRI to describe the anatomy of the proximal portion of the tarsal region (proximal tarsal region) of nonlame horses. SAMPLE 25 cadaveric equine tarsi. PROCEDURES The proximal portion of 1 tarsus from each of 25 nonlame horses with no history of tarsal lameness underwent high-field (1.5-T) and low-field (0.27-T) MRI. Resulting images were used to subjectively describe the anatomy of that region and obtain measurements of the collateral ligaments of the tarsocrural joint. RESULTS Long and short components of the lateral and medial collateral ligaments of the tarsocrural joint were identified. Various bundles of the short collateral ligaments were difficult to delineate on low-field images. Ligaments typically had low signal intensity in all sequences; however, multiple areas of increased signal intensity were identified at specific locations in most tarsi. This signal intensity was attributed to focal magic angle effect associated with orientation of collagen fibers within the ligaments at those locations. Subchondral bone of the distal aspect of the tibia was uniform in thickness, whereas that of the medial trochlear ridge of the talus was generally thicker than that of the lateral trochlear ridge. In most tarsi, subchondral bone of the talocalcaneal joint decreased in thickness from proximal to distal. CONCLUSIONS AND CLINICAL RELEVANCE Results generated in this study can be used as a reference for interpretation of MRI images of the proximal tarsal region in horses.

OBJECTIVE To identify signs of tissue-specific cortisol activity in samples of suspensory ligament (SL) and neck skin tissue from horses with and without pituitary pars intermedia dysfunction (PPID). SAMPLE Suspensory ligament and neck skin tissue samples obtained from 26 euthanized horses with and without PPID. PROCEDURES Tissue samples were collected from 12 horses with and 14 horses without PPID (controls). Two control horses had received treatment with dexamethasone; data from those horses were not used in statistical analyses. The other 12 control horses were classified as old horses (≥ 14 years old) and young horses (≤ 9 years old). Standard histologic staining, staining for proteoglycan accumulation, and immunostaining of SL and neck skin tissue sections for glucocorticoid receptors, insulin, 11β hydroxysteroid dehydrogenase type 1, and 11β hydroxysteroid dehydrogenase type 2 were performed. Findings for horses with PPID were compared with findings for young and old horses without PPID. RESULTS Compared with findings for old and young control horses, there were significantly more cells stained for glucocorticoid receptors in SL samples and for 11 β hydroxysteroid dehydrogenase type 1 in SL and skin tissue samples from horses with PPID. Insulin could not be detected in any of the SL or skin tissue samples. Horses with PPID had evidence of SL degeneration with significantly increased proteoglycan accumulation. Neck skin tissue was found to be significantly thinner in PPID-affected horses than in young control horses. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that tissue-specific dysregulation of cortisol metabolism may contribute to the SL degeneration associated with PPID in horses.

OBJECTIVE To determine the in vitro half maximal effective concentration (EC50) of ganciclovir for canine herpesvirus-1 (CHV-1) and to evaluate the efficacy of ganciclovir ophthalmic gel in dogs with experimentally induced ocular CHV-1 infection. ANIMALS 10 specific pathogen–free adult Beagles. PROCEDURES Cytotoxicity and EC50 of ganciclovir for CHV-1 were determined during in vitro experiments. During an in vivo experiment, dogs with experimentally induced ocular CHV-1 infections received 1 drop of 0.15% ganciclovir (ganciclovir group; n = 5) or artificial tear (control group; 5) ophthalmic gel in both eyes 5 times daily for 7 days, then 3 times daily for 7 days. For each dog, ophthalmic and confocal microscopic examinations were performed at predetermined times to determine severity of ocular disease and inflammation. Conjunctival swab specimens were collected at predetermined times for PCR assay analysis to determine CHV-1 shedding. RESULTS No in vitro cytotoxic effects were observed for ganciclovir concentrations ≤ 500μM. The EC50 of ganciclovir for CHV-1 was 37.7μM. No adverse effects associated with ganciclovir were observed during the in vivo experiment. Mean ocular disease and inflammation scores for the ganciclovir group were significantly lower than those for the control group. Mean duration of CHV-1 shedding for the ganciclovir group (0.4 days) was significantly shorter than that for the control group (6.2 days). CONCLUSIONS AND CLINICAL RELEVANCE Topical administration of 0.15% ganciclovir ophthalmic gel was well tolerated and effective in decreasing clinical disease scores, ocular tissue inflammation, and duration of viral shedding in dogs with experimentally induced ocular CHV-1 infection.

OBJECTIVE To evaluate efficacy of an alveolar recruitment maneuver (ARM) with positive end-expiratory pressures (PEEPs) in anesthetized horses ventilated with oxygen or heliox (70% helium and 30% oxygen). ANIMALS 6 healthy adult horses. PROCEDURES In a randomized crossover study, horses were anesthetized and positioned in dorsal recumbency. Volume-controlled ventilation was performed with heliox or oxygen (fraction of inspired oxygen [Fio2] > 90%). Sixty minutes after mechanical ventilation commenced, an ARM with PEEP (0 to 30 cm H2O in steps of 5 cm H2O every 5 minutes, followed by incremental steps back to 0 cm H2O) was performed. Peak inspiratory pressure, dynamic lung compliance (Cdyn), and Pao2 were measured during each PEEP. Indices of pulmonary oxygen exchange and alveolar dead space were calculated. Variables were compared with baseline values (PEEP, 0 cm H2O) and between ventilation gases by use of repeated-measures ANOVAs. RESULTS For both ventilation gases, ARM significantly increased pulmonary oxygen exchange indices and Cdyn. Mean ± SD Cdyn (506 ± 35 mL/cm H2O) and Pao2-to-Fio2 ratio (439 ± 36) were significantly higher and alveolar-arterial difference in Pao2 (38 ± 11 mm Hg) was significantly lower for heliox, compared with values for oxygen (357 ± 50 mL/cm H2O, 380 ± 92, and 266 ± 88 mm Hg, respectively). CONCLUSIONS AND CLINICAL RELEVANCE An ARM in isoflurane-anesthetized horses ventilated with heliox significantly improved pulmonary oxygen exchange and respiratory mechanics by decreasing resistive properties of the respiratory system and reducing turbulent gas flow in small airways.