OBJECTIVE To determine the relationship between acute volume overload and echocardiographic indices of right ventricular (RV) function and dyssynchrony in healthy dogs. ANIMALS 7 healthy Beagles. PROCEDURES Right heart catheterization and echocardiography were performed in 7 healthy anesthetized Beagles at baseline and after induction of volume overload. Volume overload was induced by IV infusion of lactated Ringer solution (150 mL/kg/h for 90 minutes). Echocardiographic indices of RV function, including peak velocity of systolic tricuspid annular motion, tricuspid annulus plane systolic excursion, fractional area change, RV Tei index, RV longitudinal strain (RVLS), and systolic RV longitudinal strain rate (RVLSR), were obtained by use of speckle tracking echocardiography (STE). In addition, SD of the systolic shortening time of the right ventricle for the 6 segments (RV-SD6) was determined with STE. RESULTS Volume overload significantly increased the RV end-diastolic pressure, compared with the baseline value. Echocardiographic indices of RV function, except for septal RVLSR, were significantly enhanced by volume overload. In contrast, RV-SD6 did not change with volume overload. Although echocardiographic indices of RV function, except for septal RVLSR, were correlated with RV end-diastolic pressure, RV-SD6 was not correlated. CONCLUSIONS AND CLINICAL RELEVANCE Echocardiographic indices of RV function, including RVLS and RVLSR, were affected by acute short-term volume overload. Therefore, results for assessment of RV function by use of STE in dogs with clinical conditions associated with right-sided chronic volume overload, such as tricuspid and pulmonic regurgitation, should be interpreted with caution.

With acrylic external-fixation frames for fracture repair the acrylic columns can be contoured to allow greater versatility in the placement of transfixation pins, thus minimizing damage to the surrounding soft tissue and making mandibular and transarticular fixation easier. However, contouring affects the stiffness and ultimate strength of the construct under axial compression. In this study, polymethylmethacrylate columns 21 mm in diameter angled at 0°, 30°, 45°, 60°, or 90° with clamps were constructed. For each angulation group, pins 3.2-mm long were placed in 6 columns, 2 pins at each end, 1.5 cm from each other, and 6 columns had no pins. Each column was allowed to polymerize for a minimum of 10 min, then was placed in a biomechanical-testing machine, the load cell at the bottom end of the column and the actuator on top, with a preload of 10 to 12 N to prevent slippage. The columns underwent axial loading at a rate of 8 mm/s until catastrophic failure occurred. Data on force and deformation were collected every 0.025 s. Both stiffness and ultimate strength of the column decreased significantly (P < 0.01), up to 77% and 70%, respectively, with each increase of angulation. The columns with pins were significantly less stiff (P < 0.05) than those without pins at angulations of 45° and 60°. However, the columns with pins did not show significant differences in ultimate strength from the columns without pins at any of the angulations. The point of failure was always at the angle of the column, demonstrating that in axial compression the weakest point is not the pin-acrylic interface when pins are eccentrically located within the column.

OBJECTIVE To evaluate the cardiovascular effects of atipamezole administered at half the volume or the same volume as dexmedetomidine to isoflurane-anesthetized cats. ANIMALS 6 adult (1 to 2 years old) domestic shorthair cats (body weight, 3 to 6 kg). PROCEDURES Each cat was anesthetized with isoflurane and rocuronium 3 times; there was a 1-week washout period between successive anesthetic procedures. For each anesthetic procedure, dexmedetomidine (5 μg/kg) was administered IV. Five minutes after dexmedetomidine was administered, atipamezole (25 or 50 μg/kg) or saline (0.9% NaCl) solution was administered IM. Pulse rate, mean arterial blood pressure (MAP), cardiac output (CO), and systemic vascular resistance (SVR) were measured during anesthesia before dexmedetomidine administration (baseline), after dexmedetomidine administration, and 15, 30, 60, and 120 minutes after administration of atipamezole or saline solution. Pulse rate and MAP were also recorded when MAP was at its lowest value. Hemodynamic variables were compared among treatments at baseline, after dexmedetomidine administration, and after administration of atipamezole or saline solution. Effects of treatment and time on all variables were assessed with mixed-effects models. RESULTS Both doses of atipamezole resulted in a significantly lower MAP than did saline solution. Pulse rate, CO, and SVR were not significantly different among treatments after atipamezole or saline solution were administered. CONCLUSIONS AND CLINICAL RELEVANCE Atipamezole administered IM at half the volume or the same volume as dexmedetomidine was ineffective at increasing pulse rate or CO in anesthetized cats that received dexmedetomidine. However, atipamezole caused short-lasting but severe arterial hypotension.

Mycoplasma bovis is a major cause of pneumonia, arthritis, and mastitis in cattle and can lead to significant economic losses. Antimicrobial resistance is a concern and further limits the already short list of drugs effective against mycoplasmas. The objective of this study was to examine changes in in vitro minimum inhibitory concentrations (MICs) of antimicrobials of aminoglycoside, fluoroquinolone, lincosamide, macrolide, pleuromutilin, phenicol, and tetracycline classes for 210 M. bovis isolates collected from 1978 to 2009. The MIC(50) values of the various antimicrobials were also compared. The MIC(50) levels for enrofloxacin and danofloxacin remained low (0.25 μg/mL) across all 3 decades. MIC(50) levels for tetracyclines, tilmicosin, and tylosin tartrate were low in the 1980s, then increased in the 1990s and remained high. In the 1980s, MIC(50) levels were low for clindamycin, spectinomycin, and tulathromycin, increased in the 1990s to 8 μg/mL (clindamycin) and 32 μg/mL (spectinomycin and tulathromycin), then decreased again in the 2000s. Members of the fluoroquinolone class of antimicrobials had the lowest MIC(50) levels across all 3 decades, which suggests in vitro susceptibility of M. bovis to this class of antimicrobials. Statistically significant associations were observed between MIC values for chlortetracycline, oxytetracycline, tylosin tartrate, and tilmicosin; between clindamycin, tulathromycin, spectinomycin, and tiamulin; and between tylosin tartrate and clindamycin. Changes in MIC levels of various antimicrobials over time show the importance of monitoring the susceptibility of mycoplasmas to antimicrobials. The number of antimicrobials that showed elevated MIC(50) levels, and therefore possibly reduced in vitro effectiveness against M. bovis, supports initiatives that promote prudent use of antimicrobials in agriculture.

Open-palm hand shields are used by veterinary workers during manual restraint for small animal radiography. The objective of this study was to measure the reduction in scatter and primary beam radiation dose to the hand provided by a full glove and an open-palm shield, using a cadaver dog to simulate restraint by 2 workers of an awake, cooperative patient undergoing thoracic and abdominal radiography. Dose was measured for 30 exposures for each condition, for a total of 795 exposures. The mean percentage decrease in scatter radiation dose was 99.9% for a full glove and 40% for an open-palm shield. The mean percentage decrease in primary beam radiation dose was 98.4% for a full glove. To optimize worker protection, fully enclosing gloves should be used during manual restraint for radiography, and body parts should never be placed in the primary beam, even when shielded.

OBJECTIVE To investigate effects of body condition on permeability of intestinal mucosa in horses. ANIMALS 13 horses (7 obese and 6 lean) from 8 to 15 years of age. PROCEDURES Body condition score was assessed, and an oral sugar test (OST) was performed to evaluate glucose and insulin dynamics. Horses were allowed a 2-week diet acclimation period and were then euthanized. Tissue samples were collected from the jejunum, ileum, cecum, pelvic flexure, right dorsal colon, and rectum. Mucosal permeability was assessed by measuring transepithelial resistance and lipopolysaccharide (LPS) flux across tissue samples mounted in Ussing chambers. RESULTS 5 obese horses and 1 lean horse had evidence of insulin dysregulation, whereas 1 obese and 5 lean horses had no abnormalities in results of the OST. Results for the OST were not available for 1 obese horse. Mucosal transepithelial resistance did not differ in any intestinal segment between obese and lean horses. Obese horses had a significantly higher LPS flux across jejunal mucosa, compared with results for lean horses, but there were no significant differences between obese and lean horses for other intestinal segments. CONCLUSIONS AND CLINICAL RELEVANCE Obese horses may have had greater paracellular mucosal permeability of jejunal mucosa to LPS, compared with that for lean horses. This finding was consistent with data for the gastrointestinal mucosa of humans and mice and supported the hypothesis that obese horses may be at higher risk from chronic exposure to increased amounts of LPS, compared with the risk for lean horses.

A total of 774 pigs were enrolled in 13 cohorts across 7 commercial farms to examine the effect of nursery feeding program on serum haptoglobin, subsequent growth performance, and carcass characteristics of finishing pigs. Pigs were weaned [23.4 ± 0.2 days of age and 5.3 ± 1.5 kg body weight (BW)] and randomly assigned to either a complex (HC: highly digestible sources of proteins, including animal proteins; N = 346) or simple (LC: corn- and soybean meal-based; N = 340) diet for 37.7 ± 1.7 days over 3 phases (1 pen per diet per cohort; pen was the experimental unit; n = 13); sex was balanced between treatments. Thereafter, pigs received common grower-finisher diets. At a targeted BW of 118 kg, pigs (subset: n = 275 and 258 for HC and LC, respectively) were processed to evaluate carcass characteristics. Nursery feeding program did not influence BW, BW gain, or serum haptoglobin at any stage of production. Feed cost was reduced by $2.82 per pig during the nursery period for the LC-fed pigs (P < 0.001). Loin eye depth, back fat depth, carcass weight, percent lean yield, and carcass gross revenue at slaughter were not influenced by nursery feeding program. Feeding LC nursery diets on commercial farms is a feasible way to reduce feed cost without negatively impacting serum haptoglobin, growth performance during or after the nursery period, or carcass value.

OBJECTIVE To assess effects of catheter diameter and injection rate of flush solution (saline [0.9% NaCl] solution) on renal contrast-enhanced ultrasonography (CEUS) with perfluorobutane in dogs. ANIMALS 5 healthy Beagles. PROCEDURES CEUS of the kidneys was performed by IV injection of contrast medium (0.0125 mL/kg) followed by injection of 5 mL of saline solution at rates of 1, 3, and 5 mL/s through a 20-gauge or 24-gauge catheter; thus, CEUS was repeated 3 times for each catheter diameter. Time-intensity curves were created for regions of interest drawn in the renal cortex and medulla. Repeatability was determined by calculating the coefficient of variation (CV). Statistical analysis was used to assess whether perfusion variables or CV of the perfusion variables was associated with catheter diameter or injection rate. RESULTS Perfusion variables did not differ significantly between catheter diameters. Time to peak enhancement (TTP) in the renal cortex was affected by injection rate, and there were significantly lower values for TTP at higher injection rates. The CEUS variables with the lowest CVs among injection rates were TTP for the renal cortex; the CV for TTP of the renal cortex was the lowest at an injection rate of 5 mL/s. CONCLUSIONS AND CLINICAL RELEVANCE Use of a 24-gauge catheter did not alter CEUS with perfluorobutane; therefore, such catheters could be used for CEUS of the kidneys of small dogs. Moreover, a rate of 5 mL/s is recommended for injection of flush solution to obtain greater accuracy for renal CEUS in Beagles.

Assays were done to assess the ability of 5 methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolates from difference sources to adhere to canine and human corneocytes. Cell wall-associated (CWA) protein gene profiles were examined to look for associations with adherence. Five MRSP strains were studied: 3 with the same CWA protein gene profile (14 genes) and belonging to sequence type (ST) 45 were isolated from a dog, a human, and the environment. The other 2 were an environmental isolate belonging to ST433 that had the lowest number of CWA protein genes (12) and a canine clinical isolate belonging to ST733 that had the greatest number of CWA protein genes (18). The 3 isolates of MRSP ST45, a major clone in Thailand, had the greatest ability to adhere to canine and human corneocytes. Nevertheless, MRSP adherence ability could not be predicted from the profile of genes encoding CWA proteins.

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.