OBJECTIVE To determine effects of hydrocortisone administration on serum leptin and adiponectin concentrations, abdominal fat distribution, and mRNA expression of leptin and adiponectin in abdominal adipose tissue of dogs. ANIMALS 12 healthy dogs. PROCEDURES Dogs received hydrocortisone (8.5 mg/kg; n = 6) or a placebo (6) orally every 12 hours for 90 days. Serum leptin and adiponectin concentrations were measured with a canine-specific ELISA on the day before (day 0; baseline) and during (days 1, 3, 7, 30, 60, and 90) administration. On days 0, 30, 60, and 90, abdominal fat mass was quantified with CT, and mRNA expression of leptin and adiponectin in abdominal fat was analyzed by use of a PCR assay. RESULTS Hydrocortisone administration resulted in an increase in visceral fat mass on days 60 and 90, compared with the mass at baseline. Visceral fat mass at the level of L3 increased during hydrocortisone administration. Serum leptin concentration began to increase on day 1 and was significantly higher than the baseline concentration on days 30 and 60. Serum adiponectin concentration on days 30, 60, and 90 was significantly lower than the baseline concentration. Leptin and adiponectin mRNA expression in abdominal fat was greater on day 30, compared with expression at baseline, but lower on days 60 and 90, compared with expression on day 30. Serum leptin concentration and visceral fat mass were correlated. CONCLUSIONS AND CLINICAL RELEVANCE Hydrocortisone administration affected abdominal fat distribution and serum leptin and adiponectin concentrations through dysregulation of leptin and adiponectin expression.

OBJECTIVE To compare use of a 3-level self-locking suture (3LSLS) technique with use of a previously described modified 3-loop pulley (M3LP) technique to repair rupture of the proximal aspect of patellar tendons in limbs from canine cadavers. SAMPLE Paired hind limbs of 6 adult mixed-breed dogs. PROCEDURES A limb from each pair was randomly assigned to be repaired by the 3LSLS technique or M3LP technique with size-2 ultrahigh-molecular-weight polyethylene and size-0 monofilament polypropylene suture, respectively. Limbs were prepared, and each patellar tendon was transected at a site chosen to simulate rupture at the proximal aspect. Tendons were repaired with the assigned techniques and mechanically tested with a biaxial servohydraulic test system; the clamp was distracted until the repair failed. Force at 1 -mm gap formation, 3-mm gap formation, and repair failure and gap size at failure were measured and compared between methods. Mode of failure was recorded. RESULTS There was no significant difference between methods for the force required to produce a 1 - or 3-mm gap in the repair. The 3LSLS technique required a significantly higher load for complete failure; gap formation immediately before failure was significantly greater for this method than for the M3LP technique. Four of 6 repairs with the M3LP technique and 0 of 6 repairs with the 3LSLS technique failed by suture breakage. CONCLUSIONS AND CLINICAL RELEVANCE The 3LSLS technique with size-2 ultrahigh-molecular-weight polyethylene suture was as effective at resistance to 1 - and 3-mm gap formation as the M3LP with size-0 monofilament polypropylene suture.

The efficacy of a porcine reproductive and respiratory syndrome (PRRS) subunit vaccine was evaluated and compared with a modified-live virus (MLV) vaccine under field conditions. Three farms were selected based on their history of respiratory diseases caused by co-infection with both PRRSV-1 and PRRSV-2. In each farm, 60 pigs were randomly allocated to 2 vaccinated and 1 unvaccinated groups (20 pigs per group). One group of pigs were administered the PRRS subunit vaccine at 21 and 42 days of age and another group administered the PRRS MLV vaccine at 21 days of age. The subunit vaccine had similar efficacy and, in some instances, performed even better than the MLV vaccine. Vaccination of pigs with either of the PRRS vaccines resulted in significantly improved growth performance in Farm B but not in Farm C. In Farm A, pigs vaccinated with the PRRS subunit vaccine had a better growth performance statistically compared to those vaccinated with the PRRS MLV vaccine. At the peak of PRRSV-1 and PRRSV-2 viremia, neutralizing antibodies and T-cell responses against PRRSV-1 and PRRSV-2 were at low levels suggesting that either vaccine is only able to provide a partial protection against co-circulating PRRSV-1 and PRRSV-2.

Drugs applied on human cancer cells can influence the rate of cell proliferation. The present study investigates the use of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide (MTT) colorimetric assay to evaluate canine tumor cell proliferation after exposure to the injectable anesthetic, propofol. Primary (CIPp) and metastatic (CIPm) canine tubular adenocarcinoma cell lines were incubated with cell culture medium (control) or propofol (1, 5, and 10 μg/mL). The MTT assays were performed after 6 and 12 hours of exposure. Measurements of absorbance were obtained for each condition with a spectrophotometer and compared with controls using a 3-way analysis of variance (P < 0.05). An increased cell proliferation rate was observed in CIPp exposed to 5 and 10 μg/mL of propofol for 6 hours and 1, 5, and 10 μg/mL for 12 hours. No significant changes were observed in CIPm after 6 hours of exposure. All propofol concentrations decreased the cell proliferation rate in CIPm after 12 hours of exposure. The MTT assays showed that exposure of CIPp to propofol for 6 and 12 hours increased cell proliferation. A decrease in the CIPm proliferation rate was observed when propofol exposure lasted for 12 hours. Further studies are warranted to better understand the role of propofol on cancer cell proliferation.

OBJECTIVE To determine the impact of mechanical ventilation (MV) and perfusion conditions on the efficacy of pulse-delivered inhaled nitric oxide (PiNO) in anesthetized horses. ANIMALS 27 healthy adult horses. PROCEDURES Anesthetized horses were allocated into 4 groups: spontaneous breathing (SB) with low (< 70 mm Hg) mean arterial blood pressure (MAP; group SB-L; n = 7), SB with physiologically normal (≥ 70 mm Hg) MAP (group SB-N; 8), MV with low MAP (group MV-L; 6), and MV with physiologically normal MAP (group MV-N; 6). Dobutamine was used to maintain MAP > 70 mm Hg. Data were collected after a 60-minute equilibration period and at 15 and 30 minutes during PiNO administration. Variables included Pao2, arterial oxygen saturation and content, oxygen delivery, and physiologic dead space-to-tidal volume ratio. Data were analyzed with Shapiro-Wilk, Mann-Whitney U, and Friedman ANOVA tests. RESULTS Pao2, arterial oxygen saturation, arterial oxygen content, and oxygen delivery increased significantly with PiNO in the SB-L, SB-N, and MV-N groups; were significantly lower in group MV-L than in group MV-N; and were lower in MV-N than in both SB groups during PiNO. Physiologic dead space-to-tidal volume ratio was highest in the MV-L group. CONCLUSIONS AND CLINICAL RELEVANCE Pulmonary perfusion impacted PiNO efficacy during MV but not during SB. Use of PiNO failed to increase oxygenation in the MV-L group, likely because of profound ventilation-perfusion mismatching. During SB, PiNO improved oxygenation irrespective of the magnitude of blood flow, but hypoventilation and hypercarbia persisted. Use of PiNO was most effective in horses with adequate perfusion.

OBJECTIVE To assess recording accuracy of right atrial and ventricular depolarization during 12-lead ECG when precordial lead V1 was positioned at each of 5 locations on the thorax of dogs with various thoracic conformations. ANIMALS 60 healthy client-owned dogs. PROCEDURES 20 dogs were allocated to each of 3 groups (brachymorphic, mesomorphic, or dolichomorphic) on the basis of thoracic conformation. Each dog remained unsedated and was positioned in right lateral recumbency for a series of five 12-lead surface ECGs, with V1 located adjacent to the sternum in the fifth intercostal space (ICS; control), at the costochondral junction (CCJ) of the right first ICS (1st-R), at the CCJ of the right third ICS, at the right third ICS where the thorax was the widest, and at the CCJ of the left first ICS. Electrocardiographic variables were compared among the 5 ECG tracings. RESULTS When V1 was at the control location, the P wave was positive for all dogs; however, consistent recording of right atrial and ventricular depolarization (ie, R wave-to-S wave ratio [R/S] < 1) occurred more frequently for brachymorphic dogs (16/20) than for dolichomorphic (7/20) and mesomorphic (6/20) dogs. When V1 was at the 1st-R location, the P wave was negative for most dogs, and R/S was < 1 for the majority of dogs in the brachymorphic (19/20), mesomorphic (17/20), and dolichomorphic (16/20) groups. The median R/S for V1 at the 1st-R location was significantly lower than that for the other 4 V1 locations. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that placement of V1 at the 1st-R location provided correct evaluation of right atrial and ventricular depolarization in most dogs regardless of thoracic conformation.

OBJECTIVE To determine whether the lactate threshold of dogs could be determined by a visual method and to assess the extent of agreement and bias among treadmill velocities for the lactate threshold as determined by visual (LTv) and polynomial (LTp) methods, glucose threshold as determined by visual (GTv) and polynomial (GTp) methods, and heart rate deflection point (HRdp) as a method for estimating the aerobic capacity of dogs. ANIMALS 18 healthy adult Beagles. PROCEDURES Each dog underwent a standardized incremental treadmill exercise test once. The test ended when the dog began to show signs of fatigue. Plasma lactate and glucose concentrations and heart rate (HR) were plotted against exercise intensity (treadmill velocity) for the duration of the test, and the LTv, GTv, and HRdp were determined visually. The LTp and GTp were determined by means of a second-order polynomial function. One-way ANOVA, Pearson correlation, Bland-Altman analyses, and ordinary least products regression were used to assess the extent of agreement and bias among the various threshold velocities. RESULTS Mean velocity did not differ significantly among the thresholds evaluated. There was a strong positive correlation between the LTv velocity and the velocity for GTv (r = 0.91), LTp (r = 0.96), GTp (r = 0.94), and HRdp (r = 0.95). CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that LTv could be determined for dogs undergoing intense exercise on a treadmill, and the treadmill velocity corresponding to the LTv was associated with the velocity for the other hallmarks of endurance. Thus, that method may be useful for prescription and evaluation of conditioning programs for dogs.

OBJECTIVE To determine the amount of negative pressure generated by syringes of various sizes with and without an attached thoracostomy tube and whether composition of thoracostomy tubes altered the negative pressure generated. SAMPLE Syringes ranging from 1 to 60 mL and 4 thoracostomy tubes of various compositions (1 red rubber catheter, 1 polyvinyl tube, and 2 silicone tubes). PROCEDURES A syringe or syringe with attached thoracostomy tube was connected to a pneumatic transducer. Each syringe was used to aspirate a volume of air 10 times. Negative pressure generated was measured and compared among the various syringe sizes and various thoracostomy tubes. RESULTS The negative pressure generated decreased as size of the syringe increased for a fixed volume across syringes. Addition of a thoracostomy tube further decreased the amount of negative pressure. The red rubber catheter resulted in the least amount of negative pressure, followed by the polyvinyl tube and then the silicone tubes. There was no significant difference in negative pressure between the 2 silicone tubes. The smallest amount of negative pressure generated was −74 to −83 mm Hg. CONCLUSIONS AND CLINICAL RELEVANCE Limited data are available on the negative pressure generated during intermittent evacuation of the thoracic cavity. For the present study, use of a syringe of ≥ 20 mL and application of 1 mL of negative suction volume resulted in in vitro pressures much more negative than the currently recommended pressure of −14.71 mm Hg for continuous suction. Additional in vitro or cadaveric studies are needed.

OBJECTIVE To describe diffusion and perfusion characteristics of the prostate gland of healthy sexually intact adult dogs as determined by use of diffusion-weighted and perfusion-weighted MRI. ANIMALS 12 healthy sexually intact adult Beagles. PROCEDURES Ultrasonography of the prostate gland was performed. Subsequently, each dog was anesthetized, and morphological, diffusion-weighted, and perfusion-weighted MRI of the caudal aspect of the abdomen was performed. The apparent diffusion coefficient was calculated for the prostate gland parenchyma in diffusion-weighted MRI images in the central ventral and peripheral dorsal areas. Perfusion variables were examined in multiple regions of interest (ROIs) in the ventral and dorsal areas of the prostate gland and in the gluteal musculature. Signal intensity was determined, and a time-intensity curve was generated for each ROI. RESULTS Results of ultrasonographic examination of the prostate gland revealed no abnormalities for any dog. Median apparent diffusion coefficient of the prostate gland was 1.51 × 10-3 mm2/s (range, 1.04 × 10-3 mm2/s to 1.86 × 10-3 mm2/s). Perfusion-weighted MRI variables for the ROIs differed between the prostate gland parenchyma and gluteal musculature. CONCLUSIONS AND CLINICAL RELEVANCE Results provided baseline information about diffusion and perfusion characteristics of the prostate gland in healthy sexually intact adult dogs. Additional studies with dogs of various ages and breeds, with and without abnormalities of the prostate gland, will be necessary to validate these findings and investigate clinical applications.

OBJECTIVE To determine the effect of topical ophthalmic administration of 0.005% latanoprost solution on aqueous humor flow rate (AHFR) and intraocular pressure (IOP) in ophthalmologically normal dogs. ANIMALS 12 adult Beagles. PROCEDURES In a masked crossover design involving two 10-day experimental periods separated by a 7-day washout period, dogs were randomly assigned to first receive latanoprost or artificial tears (control) solution and then the opposite treatment in the later experimental period. Each experimental period was divided into a baseline phase (days 1 to 3), baseline fluorophotometry assessment (day 4), treatment phase (1 drop of latanoprost or artificial tears solution administered twice daily in each eye on days 5 to 9 and once on day 10), and posttreatment fluorophotometry assessment (day 10). Measured fluorescein concentrations were used to calculate baseline and posttreatment AHFRs. The IOP was measured 5 times/d in each eye during baseline and treatment (days 5 to 9) phases. RESULTS Mean baseline and posttreatment AHFR values did not differ significantly in either experimental period (latanoprost or control). In the latanoprost period, mean IOP was significantly lower during treatment than at baseline; there was no difference in corresponding IOP values during the control period. In the latanoprost period, mean IOP was significantly higher on the first day of treatment than on subsequent treatment days. CONCLUSIONS AND CLINICAL RELEVANCE In ophthalmologically normal dogs, topical ophthalmic administration of 0.005% latanoprost solution significantly decreased IOP but did not affect AHFR. Thus, the ocular hypotensive effect of latanoprost did not appear to have been caused by a reduction in aqueous humor production.