OBJECTIVE To evaluate and compare regulation of diabetes mellitus (DM) in dogs with cataracts and well-controlled DM that received an ophthalmic preparation of prednisolone acetate versus diclofenac sodium. ANIMALS 22 client-owned dogs with cataracts and well-controlled DM. PROCEDURES A prospective, randomized, double-masked, experimental study was conducted. On days 0 and 32, serum fructosamine concentrations (SFCs), clinical scores, and body weights were determined. Dogs were assigned to receive a topically administered ophthalmic preparation of either prednisolone acetate 1% or diclofenac sodium 0.1% in each eye 4 times daily for 28 days. Data analysis was conducted with generalized linear mixed models. RESULTS Findings indicated no meaningful differences in SFCs, clinical scores, or body weights between the treatment groups on days 0 or 32. Clinical score on day 0 was positively associated with SFC, as indicated by the corresponding rate of change such that each 1 -unit increase in clinical score was associated with an approximately 45.6 ± 9.4 μmol/L increase in SFC. In addition, the least squares mean ± SEM SFC was higher in spayed females (539.20 ± 19.23 μmol/L; n = 12) than in castrated males (458.83 ± 23.70 μmol/L; 8) but did not substantially differ between sexually intact males (446.27 ± 49.72 μmol/L; 2) and spayed females or castrated males regardless of the treatment group assigned. CONCLUSIONS AND CLINICAL RELEVANCE Findings indicated no evidence for any differential effect on DM regulation (assessed on the basis of SFCs, clinical scores, and body weights) in dogs treated topically with an ophthalmic preparation of prednisolone versus an ophthalmic preparation of diclofenac. Additional research investigating plasma concentrations of topically applied ophthalmic glucocorticoid medications is warranted.

OBJECTIVE To describe histologic changes in the temporomandibular joints (TMJs) of horses of various ages. SAMPLE 22 TMJs from cadavers of 11 horses. PROCEDURES Horses were categorized into 3 age groups (group 1, 2 to 10 years old [n = 3]; group 2, 11 to 20 years old [3]; and group 3, > 20 years old [5]). Each TMJ was sectioned into 5-mm slices, preserved in formalin, decalcified in formic acid, and routinely processed for histologic analysis. Joints were systematically assessed by use of previously described methods. Multilevel mixed-effects models were used to examine the data. RESULTS The number of changes was significantly fewer and degree of changes was significantly less within the TMJs of group 1 horses, compared with those of group 3 horses. Comparison among groups revealed that the combination of temporal and mandibular scores for group 1 was significantly lower than for groups 2 or 3. Disk score did not differ significantly between groups 1 and 2, but disk scores of groups 1 and 2 were significantly lower than the disk score of group 3. CONCLUSIONS AND CLINICAL RELEVANCE The assessed lesions were associated with osteoarthritis, and they accumulated in the TMJs as horses aged. In the absence of signs of pain manifested as changes in mastication, behavior, or performance, it would be difficult to determine the point at which accrued pathological changes represented the onset of clinically important osteoarthritis of the TMJs.

The primary objective of this study was to explore the variability of Streptococcus uberis (S. uberis) isolates by extracting multilocus sequence typing (MLST) data from whole-genome sequencing. The secondary objective was to determine the distribution of the phenotypic antimicrobial resistance (AMR) and the associated AMR genes as well as the virulence gene profiles among sequence types (STs). Sixty-two isolates were recovered from 16 herds in 3 Canadian Maritime Provinces: New Brunswick (14.5%), Nova Scotia (48.3%), and Prince Edward Island (37.1%). Of these, 9, 30, and 23 were recovered from post-calving, lactational samples, and post-mastitis samples, respectively. These 62 S. uberis isolates belonged to 34 STs; 11 isolates were typed to 9 known STs and 51 isolates were classified as one of 25 new STs. Thirteen isolates were part of major clonal complexes (CCs). Post-mastitis isolates contained 10 unique STs, lactational isolates contained 11 unique STs, and post-calving isolates had 3 STs. Each farm had only 1 isolate that was a unique ST except for STs 233, 851, 855, 857, 864, and 866, which were found in multiple cows per herd on more than one farm. ST851 and ST857 were found in each of the 3 sample types, with ST857 found in cows from all 3 Maritime provinces. These results indicate that S. uberis is a diverse non-clonal pathogen with specific STs residing in clonal clusters, carrying multiple AMR genes and virulence, with a diverse phenotypic AMR.

OBJECTIVE To evaluate the effect of contrast medium injection rate on CT-derived renal perfusion estimates obtained with the maximum slope method in healthy small dogs. ANIMALS 6 healthy sexually intact male purpose-bred Beagles. PROCEDURES All dogs underwent CT perfusion analysis 3 times in a crossover design, receiving a different contrast medium injection rate (1.5, 3.0, and 4.5 mL/s) each time, with a 1-week interval between imaging sessions. All CT images were obtained at the level of the left renal hilus. The time to peak aortic enhancement (TPAE) and time to initial renal venous enhancement (TIRVE) were measured from time-attenuation curves. The renal CT perfusion estimates (blood flow and blood volume) were estimated by use of the maximum slope method, which assumes no venous outflow of contrast medium during CT perfusion analysis. RESULTS The TPAE occurred at or before the TIRVE at all injection rates. Median values of estimated blood flow and blood volume did not differ significantly among injection rates. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the assumption of no venous outflow of contrast medium during renal CT perfusion analysis with the maximum slope method was satisfied for all 3 contrast medium injection rates in the evaluated dogs. A low injection rate may be more practical than higher injection rates that require large catheters for CT perfusion analysis in small dogs such as Beagles.

OBJECTIVE To compare mechanical properties (stiffness, yield load, failure load, and deformation at failure) of 2 pearl-type locking plate system (PLS) constructs (PLS 1 and PLS 2) in a simulated fracture gap model and to compare screw push-out forces of the 2 PLSs with and without plate contouring. SAMPLE 40 PLS constructs. PROCEDURES Mechanical properties of uncontoured PLS 1 (n = 8) and PLS 2 (8) constructs were evaluated in synthetic bone-plate models under axial compression. Screw push-out forces were evaluated in 6 uncontoured and 6 contoured PLSs of each type. Variables of interest were compared between PLS groups and between contoured and uncontoured plates by statistical methods. RESULTS Yield and failure loads were higher in the PLS 1 group than in the PLS 2 group, but stiffness did not differ significantly between groups. All constructs failed by plate bending, with greater deformation in the PLS 2 group. Push-out force to screw-plate uncoupling was higher in the PLS 2 group than in the PLS 1 group for uncontoured and contoured plates. Locking mechanism failure of PLS 1 specimens was through screw-thread stripping. The PLS 2 specimens failed by node deformation followed by screwhead stripping. CONCLUSIONS AND CLINICAL RELEVANCE Distinct mechanical differences were identified between the 2 PLSs. The clinical relevance of these differences is unknown. Further research including cyclic fatigue testing is needed to reveal more clinically pertinent information.

Hantavirus is the causative agent of hemorrhagic fever with renal syndrome (HFRS). Heilongjiang Province is experiencing an epidemic of HFRS, the main causative agent is a variant of hantavirus called Seoul virus (SEOV). In this study, the entire genome of one SEOV, the DN2 strain, was sequenced and analyzed. The alignment analysis of the sequences indicated that the DN2 strain shares the highest homology with the SEOV-LYO852 strain. The nucleotide identity is 97.6% for the S segment, 97.7% for the M segment, and 98.0% for the L segment. The corresponding amino acid sequence homologies are 99.1%, 98.9% and 99.8%. The phylogenetic analysis of the segments suggests that the DN2 strain has a high genetic relationship with SEOV strains and no genetic recombination occurs.

OBJECTIVE To evaluate the effects of providing 100% O2, compared with provision of room air, in sedated spontaneously breathing inland bearded dragons (Pogona vitticeps). ANIMALS 8 adult bearded dragons. PROCEDURES Animals were sedated with alfaxalone (20 mg/kg, SC) and received 21% O2 (equivalent to room air) or 100% O2 via face mask (flow rate, 1 L/min) in a randomized, blinded, complete crossover study (2-week interval between treatments). Sedation variables, cardiopulmonary variables, venous blood gas values, and postsedation food intake were evaluated. RESULTS Respiratory rate, heart rate, oxygen saturation, and sedation quality were comparable between treatments. Venous blood gas analysis revealed a higher total Pco2 and HCO3− concentration for the 21% O2 treatment. Postsedation food intake was not affected by the inspired oxygen fraction provided during sedation. CONCLUSIONS AND CLINICAL RELEVANCE The fraction of inspired oxygen did not appear to have clinically relevant effects on physiologic variables of bearded dragons during and after sedation. Therefore, provision of 100% O2 can be considered for use in sedated bearded dragons without the risk of inducing hypoventilation. Similarly, failure to provide 100% O2 would be unlikely to result in clinically relevant consequences in healthy sedated bearded dragons.

OBJECTIVE To determine whether an enrofloxacin–silver sulfadiazine emulsion (ESS) labeled for treatment of otitis externa in dogs has ototoxic effects in rabbits following myringotomy. ANIMALS 6 healthy adult New Zealand White rabbits. PROCEDURES Rabbits were anesthetized for brainstem auditory-evoked response (BAER) tests on day 0. Myringotomy was performed, and BAER testing was repeated. Saline (0.9% NaCl) solution and ESS were then instilled in the left and right middle ears, respectively, and BAER testing was repeated prior to recovery of rabbits from anesthesia. Application of assigned treatments was continued every 12 hours for 7 days, and rabbits were anesthetized for BAER testing on day 8. Rabbits were euthanized, and samples were collected for histologic (6 ears/treatment) and scanning electron microscopic (1 ear/treatment) examination. RESULTS Most hearing thresholds (11/12 ears) were subjectively increased after myringotomy, with BAER measurements ranging from 30 to 85 dB in both ears. All day 8 hearing thresholds exceeded baseline (premyringotomy) values; results ranged from 30 to 85 dB and 80 to > 95 dB (the upper test limit) in saline solution–treated and ESS-treated ears, respectively. All ESS-treated ears had heterophilic otitis externa, epithelial hyperplasia of the external ear canal, various degrees of mucoperiosteal edema, and periosteal new bone formation on histologic examination. Scanning electron microscopy revealed that most outer hair cells in the ESS-treated ear lacked stereocilia or were absent. CONCLUSIONS AND CLINICAL RELEVANCE Results supported that ESS has ototoxic effects in the middle ear of rabbits. Further research is needed to confirm these findings. Myringotomized laboratory rabbits may be useful to study ototoxicity of drugs used in human medicine.

OBJECTIVE To evaluate glomerular filtration rate (GFR) estimation by means of plasma clearance of iohexol (IOX) in domestic rabbits and to assess accuracy of limited-sampling models for GFR estimation. ANIMALS 6 healthy domestic rabbits (Oryctolagus cuniculus). PROCEDURES Each rabbit received IOX (64.7 mg/kg [0.1 mL/kg], IV), and blood samples were collected at predetermined times before and after administration. Plasma IOX concentration was determined by high-performance liquid chromatography. The pharmacokinetics of IOX was determined by a noncompartmental method. For each rabbit, plasma clearance of IOX was determined by dividing the total IOX dose administered by the area under the concentration-time curve indexed to the subject's body weight. The GFR estimated from the plasma IOX concentration at 6 sampling times (referent model) was compared with that estimated from the plasma IOX concentration at 5 (model A), 4 (model B), and 3 (models C, D, and E) sampling times (limited-sampling models). RESULTS Mean ± SD GFR was 4.41 ± 1.10 mL/min/kg for the referent model and did not differ significantly from the GFR estimated by any of the limited-sampling models. The GFR bias magnitude relative to the referent model was smallest for model D in which GFR was estimated from plasma IOX concentrations at 5, 15, and 90 minutes after IOX administration. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that plasma clearance of IOX was a safe, reliable, accurate, and clinically feasible method to estimate GFR in domestic rabbits. Further research is necessary to refine the method.

OBJECTIVE To determine the pharmacokinetics and adverse effects of maropitant citrate after IV and SC administration to New Zealand White rabbits (Oryctolagus cuniculus). ANIMALS 11 sexually intact (3 males and 8 females) adult rabbits. PROCEDURES Each rabbit received maropitant citrate (1 mg/kg) IV or SC. Blood samples were collected at 9 (SC) or 10 (IV) time points over 48 hours. After a 2-week washout period, rabbits received maropitant by the alternate administration route. Pharmacokinetic parameters were calculated. Body weight, food and water consumption, injection site, mentation, and urine and fecal output were monitored. RESULTS Mean ± SD maximum concentration after SC administration was 14.4 ± 10.9 ng/mL and was detected at 1.25 ± 0.89 hours. Terminal half-life after IV and SC administration was 10.4 ± 1.6 hours and 13.1 ± 2.44 hours, respectively. Bioavailability after SC administration was 58.9 ± 13.3%. Plasma concentration at 24 hours was 2.87 ± 1.69 ng/mL after IV administration and 3.4 ± 1.2 ng/mL after SC administration. Four rabbits developed local dermal reactions at the injection site after SC injection. Increased fecal production was detected on the day of treatment and 1 day after treatment. CONCLUSIONS AND CLINICAL RELEVANCE Plasma concentrations of rabbits 24 hours after SC and IV administration of maropitant citrate (1 mg/kg) were similar to those of dogs at 24 hours. Reactions at the SC injection site were the most common adverse effect detected. Increased fecal output may suggest an effect on gastrointestinal motility. Additional pharmacodynamic and multidose studies are needed.