OBJECTIVE To determine whether dual-energy CT (DECT) could accurately differentiate the composition of common canine uroliths in a phantom model. SAMPLE 30 canine uroliths with pure compositions. PROCEDURES Each urolith was composed of ≥ 70% struvite (n = 10), urate (8), cystine (5), calcium oxalate (4), or brushite (3) as determined by standard laboratory methods performed at the Canadian Veterinary Urolith Centre. Uroliths were suspended in an agar phantom, and DECT was performed at low (80 kV) and high (140 kV) energies. The ability of low- and high-energy CT numbers, DECT number, and DECT ratio to distinguish uroliths on the basis of composition was assessed with multivariate ANOVA. RESULTS No single DECT measure differentiated all urolith types. The DECT ratio differentiated urate uroliths from all other types of uroliths. The DECT and low-energy CT numbers were able to differentiate between 8 and 7 pairs of urolith types, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that DECT was unable to differentiate common types of canine uroliths in an in vitro model; therefore, it is unlikely to be clinically useful for determining urolith composition in vivo. Given that the primary reasons for determining urolith composition in vivo are to predict response to shock wave lithotripsy and develop a treatment plan, future research should focus on the correlation between DECT measurements and urolith fragility rather than urolith composition.

OBJECTIVE To purify and characterize equine vitamin D-binding protein (VDBP) from equine serum and to evaluate plasma concentrations of VDBP in healthy horses and horses with gastrointestinal injury or disease. ANIMALS 13 healthy laboratory animals (8 mice and 5 rabbits), 61 healthy horses, 12 horses with experimentally induced intestinal ischemia and reperfusion (IR), and 59 horses with acute gastrointestinal diseases. PROCEDURES VDBP was purified from serum of 2 healthy horses, and recombinant equine VDBP was obtained through a commercial service. Equine VDBP was characterized by mass spectrometry. Monoclonal and polyclonal antibodies were raised against equine VDBP, and a rocket immunoelectrophoresis assay for equine VDBP was established. Plasma samples from 61 healthy horses were used to establish working VDBP reference values for study purposes. Plasma VDBP concentrations were assessed at predetermined time points in horses with IR and in horses with naturally occurring gastrointestinal diseases. RESULTS The working reference range for plasma VDBP concentration in healthy horses was 531 to 1,382 mg/L. Plasma VDBP concentrations were significantly decreased after 1 hour of ischemia in horses with IR, compared with values prior to induction of ischemia, and were significantly lower in horses with naturally occurring gastrointestinal diseases with a colic duration of < 12 hours than in healthy horses. CONCLUSIONS AND CLINICAL RELEVANCE Plasma VDBP concentrations were significantly decreased in horses with acute gastrointestinal injury or disease. Further studies and the development of a clinically relevant assay are needed to establish the reliability of VDBP as a diagnostic and prognostic marker in horses.

OBJECTIVE To determine manubrium heart scores (MHSs) from measurements of cardiac short-axis length (cSAL) and long-axis length (cLAL) relative to the corresponding manubrium length (ML) on thoracic radiographic views of dogs and assess correlation of MHSs with vertebral heart scores (VHSs). ANIMALS 120 clinically normal large-breed dogs (LBDs) and small-breed dogs (SBDs). PROCEDURES On right lateral views (RLVs) and ventrodorsal views (VDVs) for each dog, cSAL and cLAL were measured and expressed as a ratio; the cSAL:ML ratio (short-MHS), cLAL:ML ratio (long-MHS), and cSAL-and-cLAL:ML ratio (overall-MHS) were also calculated. The VHS was determined from the RLV. Correlation of VHS with MHS was assessed. RESULTS On RLVs and VDVs, mean cSAL:cLAL ratios were 0.77 (SD, 0.05) and 0.72 (SD, 0.05), respectively, in 60 LBDs and 0.81 (SD, 0.06) and 0.78 (SD, 0.06), respectively, in 60 SBDs. In LBDs, mean short-MHS, long-MHS, and overall-MHS were 2.1 (SD, 0.22), 2.7 (SD, 0.24), and 4.8 (SD, 0.5), respectively, on RLVs and 2.3 (SD, 0.26), 3.2 (SD, 0.34), and 5.4 (SD, 0.6), respectively, on VDVs. In SBDs, mean short-MHS, long-MHS, and overall-MHS were 2.4 (SD, 0.39), 2.9 (SD, 0.50), and 5.3 (SD, 0.83), respectively, on RLVs and 2.5 (SD, 0.44), 3.2 (SD, 0.51), and 5.8 (SD, 0.92), respectively, on VDVs. Mean VHSs were 10.73 (SD, 0.52) and 10.27 (SD, 0.81) in LBDs and SBDs, respectively. A significant correlation was identified between VHS and each MHS in LBDs. CONCLUSIONS AND CLINICAL RELEVANCE In the dogs evaluated, radiographic cardiac dimensions and MHSs were correlated. Validity of the MHS for cardiac dimension assessment in other healthy dogs and dogs with cardiac disease warrants investigation.

The aim of this case series was to describe the differences between maternal and fetal blood-gas results during anesthesia. Sixteen singleton adult merino ewes weighing 60.1 ± 5.1 kg at 125.7 d (124 to 126 d) gestation were anesthetized. Maternal (radial) and fetal (umbilical) arterial blood gas samples were collected 79 ± 6 min after the start of anesthesia if maternal mean arterial pressure (MAP) was stable and > 65 mmHg. Fetal pH, partial arterial pressure of oxygen (PaO2), glucose, arterial hemoglobin oxygen saturation (SaO2), sodium, and chloride were significantly lower and fetal partial arterial pressure of carbon dioxide (PaCO2), lactate, hematocrit, total hemoglobin, potassium, and calcium were significantly higher than maternal blood-gas values. Fetal pH, PaO2, and BE were lower and fetal lactate was higher than fetal umbilical arterial samples previously reported, which may indicate a non-reassuring fetal status. Further refinement of the ovine experimental model is warranted with fetal monitoring during maternal anesthesia.

rcine reproductive and respiratory syndrome, caused by the porcine reproductive and respiratory syndrome virus (PRRSV), is an economically important disease in the swine industry. Previous studies demonstrated the presence of the virus in pig meat and its transmissibility by oral consumption. This study further analyzed the infectivity of PRRSV in commercial pig meat. Fresh bottom meat pieces (n = 1500) randomly selected over a period of 2 y from a pork ham boning plant located in Quebec, Canada, were tested by reverse transcriptase polymerase chain reaction (RT-PCR). Each trimmed meat was stored in the plant freezer, subsampled weekly for up to 15 wk, and tested with quantitative RT-PCR to determine the viral load. Meat infectivity was evaluated using specific pathogen-free piglets, each fed with approximately 500 g of meat at the end of the storage time. Genotype-specific RT-PCR confirmed the presence of PRRSV mainly during cold weather in 0.73% of the fresh meat pieces. Wild and vaccine strains of genotype 2 were detected. Porcine reproductive and respiratory syndrome virus nucleic acid was stable in meat stored at around -20°C during the 15 wk. Serological and molecular analysis showed the transmission of infection by a majority of PRRSV positive meat pieces (5/9) fed orally to naïve recipients. The results confirmed a low prevalence of PRRSV in market's pig meat, and virus transmissibility by oral consumption to naïve recipients even after several weeks of storage in a commercial freezer. It occurred mainly with meat harboring the highest PRRSV RNA copies, in the range of 109 copies per 500 g of meat, with both wild type and vaccine-related strains.

OBJECTIVE To determine whether passive ureteral dilation (PUD) would occur after an indwelling ureteral stent was left in place in healthy dogs for 2 or 6 weeks, ureteroscopy would be possible at the time of stent removal, and PUD would be reversible after stent removal. ANIMALS 5 healthy adult female Beagles. PROCEDURES A ureteral stent was cystoscopically placed in each ureter of each dog with fluoroscopic guidance (week 0). One stent was removed from 1 ureter in each dog after 2 weeks (ureter group 1), and the other was removed after 6 weeks (ureter group 2); removal timing was randomized. Computed tomographic excretory urography was performed every 2 weeks from weeks 0 through 10 to measure ureteral diameters. Ureteroscopy was attempted at the time of ureteral stent removal in each group. Ureteral diameters were compared among measurement points. RESULTS The degree of PUD was significant after 2 and 6 weeks of stent placement in both ureter groups. Mean diameter of the midportion of the ureter in both groups prior to stent placement was 1.70 mm (range, 1.3 to 2.7 mm). At stent removal, mean diameter of the midportion of the ureter was 2.86 mm (range, 2.4 to 3.1 mm) in group 1 and 2.80 mm (range, 2.1 to 3.4 mm) in group 2. Ureteroscopy was successfully performed in all dogs up to the renal pelvis. Compared with week 0 values for diameter of the midportion of the ureter, the degree of PUD induced by stent placement had reversed by week 8 in group 1 (mean diameter, 2.00 mm [range, 1.5 to 2.3 mm]). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ureteral stent placement for 2 weeks would result in sufficient PUD in healthy dogs to allow ureteroscopy at the time of stent removal and that the original ureteral diameter would eventually be restored. Additional research is needed to determine whether findings would be similar for dogs with urinary tract disease.

OBJECTIVE To assess the possible impact of medetomidine on concentrations of alfaxalone in plasma, when coadministered as a constant rate infusion (CRI) to dogs, and to determine the possible impact of medetomidine on the cardiopulmonary effects of alfaxalone during CRI. ANIMALS 8 healthy adult Beagles. PROCEDURES 3 treatments were administered in a randomized crossover design as follows: 1 = saline (0.9% NaCl) solution injection, followed in 10 minutes by induction of anesthesia with alfaxalone (loading dose, 2.4 mg/kg; CRI, 3.6 mg/kg/h, for 60 minutes); 2 = medetomidine premedication (loading dose, 4.0 μg/kg; CRI, 4.0 μg/kg/h), followed by alfaxalone (as in treatment 1); and, 3 = medetomidine (as in treatment 2) and MK-467 (loading dose, 150 μg/kg; CRI, 120 μg/kg/h), followed by alfaxalone (as in treatment 1). The peripherally acting α2-adrenoceptor antagonist MK-467 was used to distinguish between the peripheral and central effects of medetomidine. Drugs were administered IV via cephalic catheters, and there was a minimum of 14 days between treatments. Cardiopulmonary parameters were measured for 70 minutes, and jugular venous blood samples were collected until 130 minutes after premedication. Drug concentrations in plasma were analyzed with liquid chromatography–tandem mass spectrometry. RESULTS The characteristic cardiovascular effects of medetomidine, such as bradycardia, hypertension, and reduction in cardiac index, were obtunded by MK-467. The concentrations of alfaxalone in plasma were significantly increased in the presence of medetomidine, indicative of impaired drug distribution and clearance. This was counteracted by MK-467. CONCLUSIONS AND CLINICAL RELEVANCE The alteration in alfaxalone clearance when coadministered with medetomidine may be attributed to the systemic vasoconstrictive and bradycardic effects of the α2-adrenoceptor agonist. This could be clinically important because the use of α2-adrenoceptor agonists may increase the risk of adverse effects if standard doses of alfaxalone are used.

OBJECTIVE To investigate protein kinase CK2 (CK2) expression in squamous cell carcinoma (SCC) of cats and to examine effects of CK2 downregulation on in vitro apoptosis and viability in SCC. SAMPLE Biopsy specimens of oral mucosa and testis and blood samples from clinically normal cats, biopsy specimens of oral SCC from cats, and feline SCC (SCCF1) and mammary gland carcinoma (K12) cell lines. PROCEDURES Immunohistochemically labeling for CK2α was performed on biopsy specimens. Sequences of the CK2α subunit gene and CK2α’ subunit gene in feline blood and feline cancer cell lines were determined by use of PCR and reverse-transcription PCR assays followed by direct Sanger sequencing. Specific small interfering RNAs (siRNAs) were developed for feline CK2α and CK2α'. The SCCF1 cells were treated with siRNA and assessed 72 hours later for CK2α and CK2α’ expression and markers of apoptosis (via western blot analysis) and for viability (via 3-[4,5-dimethylthiazol-2-yl]-5-[3-carboxymethoxyphenyl]-2-[4-sulfophenyl]-2H-tetrazolium assays). RESULTS CK2α was expressed in all feline oral mucosa samples and 7 of 8 oral SCC samples. Expression of CK2α and CK2α’ was successfully downregulated in SCCF1 cells by use of siRNAs, which resulted in decreased viability and induction of apoptosis. CONCLUSIONS AND CLINICAL RELEVANCE In this study, CK2 appeared to be a promising therapeutic target for SCCs of cats. A possible treatment strategy for SCCs of cats would be RNA interference that targets CK2.

OBJECTIVE To determine the pharmacokinetics of meloxicam in domestic hens and duration and quantity of drug residues in their eggs following PO administration of a single dose (1 mg of meloxicam/kg). ANIMALS 8 healthy adult White Leghorn hens. PROCEDURES Hens were administered 1 mg of meloxicam/kg PO once. A blood sample was collected immediately before and at intervals up to 48 hours after drug administration. The hens' eggs were collected for 3 weeks after drug administration. Samples of the hens' plasma, egg whites (albumen), and egg yolks were analyzed by high-performance liquid chromatography. RESULTS The half-life, maximum concentration, and time to maximum concentration of meloxicam in plasma samples were 2.8 hours, 7.21 μg/mL, and 2 hours, respectively. Following meloxicam administration, the drug was not detected after 4 days in egg whites and after 8 days in egg yolks. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that meloxicam administered at a dose of 1 mg/kg PO in chickens appears to maintain plasma concentrations equivalent to those reported to be therapeutic for humans for 12 hours. The egg residue data may be used to aid establishment of appropriate drug withdrawal time recommendations.

OBJECTIVE To characterize the maternal and fetal cardiopulmonary effects of a low-dose infusion of dexmedetomidine without a loading dose in pregnant ewes anesthetized with sevoflurane. ANIMALS 11 pregnant ewes. PROCEDURES Anesthesia was induced with propofol and maintained with sevoflurane. Ewes and fetuses were instrumented with arterial and venous catheters, and thermodilution–pulmonary arterial catheters were placed in the ewes. Baseline measurements were obtained at an end-tidal sevoflurane concentration of 3.4%, then dexmedetomidine (2 μg/kg/h, IV) was infused for 90 minutes without a loading dose. Cardiovascular and blood gas variables were measured at predetermined time points. RESULTS Dexmedetomidine infusion resulted in approximately 30% decreases in maternal systemic vascular resistance, blood pressure, and heart rate. Maternal cardiac index, oxygenation variables, and acid-base status remained unchanged, whereas pulmonary arterial pressure, pulmonary vascular resistance, and stroke volume increased, compared with baseline values. Uterine blood flow decreased by approximately 30% to 36%. Fetal heart rate and blood pressure remained unchanged, but significant increases in fetal plasma glucose and lactate concentrations were detected. CONCLUSIONS AND CLINICAL RELEVANCE Pregnant ewes receiving a combination of sevoflurane and an infusion of dexmedetomidine without a loading dose had cardiac index in acceptable ranges and maintained normoxia. This balanced anesthesia did not produce significant changes in fetal blood pressure or heart rate. However, the increase in fetal plasma lactate concentration and changes in maternal pulmonary vascular resistance and uterine blood flow require further investigation to better elucidate these effects.