The purpose of this study was to develop a percutaneous lung biopsy technique to be used on steers in a commercial feedlot setting. Thirty-four crossbred steer and heifer calves from a commercial feedlot in southern Alberta were used in this study. The calves originated from the auction market and all were chronically affected with bovine respiratory disease (BRD). A technique was developed to obtain a lung sample from the right cranioventral lung lobe, intercostal space (ICS) 2, using a manual or an automatic biopsy instrument with a 14- or 12-gauge (ga) biopsy needle. Overall, lung parenchyma was successfully harvested in 55.9% of experimental animals and in 55.0% of lung biopsy trials. Compared with postmortem diagnosis, the biopsy resulted in the same pathologic diagnosis for 75% of biopsy samples when evaluated using standardized criteria by the same veterinary pathologist. The success rate was 61.5% and 42.9% in a hospital or field setting, respectively. With an automatic instrument, lung was recovered from 57.9% and 37.5% of samples obtained using a 12- or 14-ga biopsy needle, respectively. One experimental animal or 2.9% of the total had fatal complications from the procedure. In a commercial feedlot setting, the procedure took 20 min for each animal. Percutaneous lung biopsy of the right cranioventral lung lobe may be a viable technique when used on feedlot steers affected with chronic pneumonia. These findings suggest that using an automatic instrument with either a 14- or 12-ga biopsy needle may yield lung samples that are suitable for histopathological evaluation. However, this technique needs to be further evaluated in a field setting.

Objective—To investigate whether plasma activity of matrix metalloproteinase (MMP)-2 and -9 was associated with severity of myxomatous mitral valve disease (MMVD) in dogs and to assess potential associations between MMP activity and dog characteristics, echocardiographic variables, systolic arterial blood pressure (SAP), heart rate, cardiac troponin I (cTnI) concentration, and C-reactive protein concentration. Animals—75 client-owned dogs. Procedures—Severity of MMVD was assessed by use of echocardiography. Plasma activity of latent (pro-MMP) and active MMP-2 and -9 was analyzed via zymography. Plasma concentration of cTnI was analyzed with a high-sensitivity cTnI assay, and C-reactive protein concentration was analyzed with a canine-specific ELISA. Results—Pro-MMP-9, active MMP-9, and pro-MMP-2 were detected, but active MMP-2 was not. No significant differences were found in MMP concentrations among the 4 MMVD severity groups. Activity of pro-MMP-9 decreased with decreases in SAP and was higher in male dogs than in female dogs. Activity of MMP-9 decreased with increases in left ventricular end-systolic dimension and with decreases in SAP and cTnI concentration. Left ventricular end-systolic dimension was the variable most strongly associated with MMP-9 activity. No associations were found between the activity of pro-MMP-2 and investigated variables. Conclusions and Clinical Relevance—Plasma MMP-9 activity decreased with increases in the end-systolic left ventricular internal dimension and decreases in SAP. Hence, evaluation of MMP-9 activity has the potential to provide unique information about the myocardial remodeling process in dogs with MMVD.

Glanzmann thrombasthenia (GT) is characterized by a defect of platelet aggregation. This autosomal recessive genetic disorder is caused by an abnormality of the platelet glycoprotein receptors alpha IIb or beta III. Recently, we identified a horse with clinical and pathological features of GT. The aim of this study was to describe this case of GT at the molecular level. A point mutation from G to C in exon 2 of ITGA2B causing a substitution of the expected amino acid arginine 72 (Arg72) by a proline (Pro72) was encountered. This amino acid change may result in abnormal structural conformations that yield an inactive alpha IIb subunit. The genomic DNA analysis showed that this horse was homozygous for the missense mutation.

Objective—To characterize pharmacokinetics and pharmacodynamics of detomidine gel administered sublingually in accordance with label instructions to establish appropriate withdrawal guidelines for horses before competition. Animals—12 adult racehorses. Procedures—Horses received a single sublingual administration of 0.04 mg of detomidine/kg. Blood samples were collected before and up to 72 hours after drug administration. Urine samples were collected for 5 days after detomidine administration. Plasma and urine samples were analyzed via liquid chromatography–mass spectrometry, and resulting data were analyzed by use of noncompartmental analysis. Chin-to-ground distance, heart rate and rhythm, glucose concentration, PCV, and plasma protein concentration were also assessed following detomidine administration. Results—Mean ± SD terminal elimination half-life of detomidine was 1.5 ± 1 hours. Metabolite concentrations were below the limit of detection (0.02, 0.1, and 0.5 ng/mL for detomidine, carboxydetomidine, and hydroxydetomidine, respectively) in plasma by 24 hours. Concentrations of detomidine and its metabolites were below the limit of detection (0.05 ng/mL for detomidine and 0.10 ng/mL for carboxydetomidine and hydroxydetomidine) in urine by 3 days. All horses had various degrees of sedation after detomidine administration. Time of onset was ≤ 40 minutes, and duration of sedation was approximately 2 hours. Significant decreases, relative to values at time 0, were detected for chin-to-ground distance and heart rate. There was an increased incidence and exacerbation of preexisting atrioventricular blocks after detomidine administration. Conclusions and Clinical Relevance—A 48-hour and 3-day withdrawal period for detection in plasma and urine samples, respectively should be adopted for sublingual administration of detomidine gel.

Objective—To assess and compare the expression of perinuclear antineutrophilic cytoplasmic antibodies (pANCA) in sera obtained from dogs with inflammatory bowel disease (IBD) and dogs with intestinal lymphoma. Animals—104 dogs with IBD and 23 dogs with intestinal lymphoma. Procedures—Each ill dog had persistent gastrointestinal signs (> 3 weeks in duration) and absence of response to diet changes or antimicrobial treatments. Gastrointestinal endoscopy was performed in ill dogs to obtain intestinal biopsy specimens for histologic confirmation of IBD or lymphoma. A serum sample was obtained from each ill dog. Neutrophils were isolated from a blood sample from the healthy dog; neutrophil-bearing slides were incubated with serum from each ill dog and examined for expression of pANCA by use of an indirect immunofluorescence technique. Detection of cells that had a perinuclear fluorescence pattern was considered a positive result. Results—The 2 groups of dogs did not differ with regard to breed and sex but did differ with regard to age. Expression of pANCA was detected in 38 of the 104 (36.5%) dogs with IBD and 4 of the 23 (17.4%) dogs with intestinal lymphoma. Although the frequency of pANCA expression was higher in dogs with IBD, compared with findings in dogs with intestinal lymphoma, the difference was not significant. Conclusions and Clinical Relevance—Results indicated that circulating pANCA are present in some dogs with IBD or intestinal lymphoma. However, pANCA detection does not seem to be useful for distinguishing dogs with IBD from dogs with intestinal lymphoma.

Objective—To evaluate enterotoxin production, enterotoxin gene distribution, and genetic diversity of Staphylococcus aureus in milk obtained from cows with subclinical mastitis. Sample—Milk samples obtained from 350 cows (1,354 mammary glands) on 11 Wisconsin dairy farms. Procedures—Of 252 S aureus isolates obtained from 146 cows, 83 isolates (from 66 cows with subclinical mastitis) were compared genotypically by use of pulsed-field gel electrophoresis and via PCR identification of toxic shock syndrome toxin 1 (TSST-1) and classical S aureus enterotoxin genes (sea, seb, sec, sed, and see). Results—Among the 83 S aureus isolates, ≥ 1 enterotoxin genes were identified in 8 (9.6%). Enterotoxin gene distribution was as follows: TSST-1, 7 isolates (8.4%); sec, 5 isolates (6.0%); and sed, 2 isolates (2.4%). Enterotoxin genes sea, seb, and see were not identified. Twelve pulsotypes and 5 subtypes were identified among the 83 isolates; 5 of the 12 pulsotypes were represented by only 1 isolate. In cows of 1 herd, only a single S aureus pulsotype was detected; in cows on most other farms, a variety of pulsotypes were identified. One pulsotype was recovered from 4 farms (n = 23 cows) and another from 5 other farms (16). Isolates with an enterotoxin gene were represented by 6 pulsotypes. Conclusions and Clinical Relevance—S aureus classical enterotoxins and TSST-1 were rarely recovered from milk samples obtained from cows with subclinical mastitis in Wisconsin. Diverse pulsotypes of S aureus were detected within and among farms, indicating that different strains of S aureus cause subclinical mastitis in dairy cows.

Objective—To determine values for total body water (TBW), extracellular fluid volume (ECFV), intracellular fluid volume (ICFV), and plasma volume (PV) in healthy neonatal (< 24 hours old) foals and to create a multifrequency bioelectrical impedance analysis (MF-BIA) model for use in neonatal foals. Animals—7 healthy neonatal foals. Procedures—Deuterium oxide (0.4 g/kg, IV), sodium bromide (30 mg/kg, IV), and Evans blue dye (1 mg/kg, IV) were administered to each foal. Plasma samples were obtained following an equilibration period, and the TBW, ECFV, ICFV, and PV were calculated for each foal. An MF-BIA model was created by use of morphometric measurements from each foal. Results—Mean ± SD values were obtained for TBW (0.744 ± 0.024 L/kg), ICFV (0.381 ± 0.018 L/kg), ECFV (0.363 ± 0.014 L/kg), and PV (0.096 ± 0.015 L/kg). The 95% limits of agreement between the MF-BIA and indicator dilution techniques were within ± 2 L for TBW and ECFV. Conclusions and Clinical Relevance—Fluid volumes in neonatal foals were found to be substantially larger than fluid volumes in adult horses. Multifrequency bioelectrical impedance analysis may be a useful technique for predicting TBW, ICFV, and ECFV in neonatal foals.

Objective: To evaluate influence of electrode position on cardioversion energy (CE; energy delivered in the shock at which cardioversion was achieved) during transvenous electrical cardioversion (TVEC) in horses with atrial fibrillation. Animals: 37 horses with atrial fibrillation (41 cardioversion events). Procedures: Records were reviewed to identify horses that underwent TVEC for treatment of atrial fibrillation. Signalment and CE were recorded. Electrode positions in the right atrium and pulmonary artery were identified on intraoperative radiographs. An orthogonal coordinate space was created, and electrode y- and z-axis coordinates and shadow lengths were determined. Trigonometric modeling was used to estimate x-axis electrode positions that resulted in observed shadows. Postmortem casts of catheterized horses were used to assess electrode paths and anatomic relationships. Model assumptions were tested by use of these and a theoretical data set. Relationships between signalment, electrode position, and CE were assessed via multivariate analysis. Results: Sex and y-axis differences between electrode positions were significant predictors of CE. Population stratification based on examination of residuals improved model strength; populations differed in z-axis variables and in CE. Decreasing distance between electrodes and pulmonary artery electrode positions ventral to the right atrium were associated with increased CE. Agreement between estimated and actual x-axis coordinates was poor. Conclusions and Clinical Relevance: Optimal electrode positioning can reduce the energy requirement for successful TVEC and may eventually support application of TVEC under short-term IV anesthesia and potentially increase chances of treatment response. Further investigation into these relationships is warranted.

Objective-To evaluate 2 commercially available transfection reagents for transfection efficiency and distribution of small interfering RNA (siRNA) molecules to chondrocytes in monolayer cultures and full-thickness cartilage explants from guinea pigs and horses. Sample-Cartilage explants from 5 one-month-old and 3 adult guinea pigs and 5 adult clinically normal horses. Procedures-Monolayer chondrocytes and uniform cartilage explants were exposed to 1 of 2 siRNA transfection complexes according to manufacturers' protocols (1micromolar [1×]). Additionally, monolayer chondrocytes were exposed to 2× the suggested amount of a proprietary siRNA molecule. Full-thickness cartilage explants were treated with 1× (1micromolar), 2× (2micromolar), and 4× (4micromolar) or 1× (0.13micromolar), 4× (0.52micromolar), and 8× (1.04micromolar) the recommended concentrations of the proprietary siRNA and the cationic liposome siRNA, respectively, in equivalent media volumes. Use of fluorescent siRNA duplexes allowed quantification of transfected cells via flow cytometry and direct visualization of the depth and distribution of in situ transfection via fluorescent microscopy. Results-With both transfection reagents, > 90% of monolayer chondrocytes were transfected. In explants, only use of the proprietary molecule achieved > 50% transfection efficiency, whereas use of the cationic liposome achieved < 20%. Only the proprietary molecule-treated cartilage consistently contained fluorescent cells throughout all zones; the cationic liposome-transfected chondrocytes were restricted to explant surfaces. Conclusions and Clinical RelevanceRobust transfection of chondrocytes in monolayer was achieved with both reagents, but only use of the proprietary molecule attained effective full-thickness transfection of explants that may allow relevant transcript reduction via RNAi.

Objective-To compare inhibitory effects of topically applied 1% prednisolone acetate suspension, 0.03% flurbiprofen solution, 0.1% dexamethasone suspension, and 0.1% diclofenac solution on paracentesis-induced blood-aqueous barrier breakdown in cats. Animals-9 healthy cats. Procedures-Paracentesis of the anterior chamber was performed in both eyes of each cat. One eye of each cat was treated with a topically administered anti-inflammatory medication (1% prednisolone [n = 7 cats], 0.03% flurbiprofen [7], 0.1% dexamethasone [9], or 0.1% diclofenac [8]) immediately following paracentesis and at 6, 10, and 24 hours after paracentesis. The contralateral untreated eye served as the control eye. Each cat had a 6-day washout period between experimental drugs. Breakdown of the blood-aqueous barrier was quantified by use of laser flaremetry. Results-Topical administration of 1% prednisolone significantly reduced aqueous humor flare at 4, 8, and 26 hours after paracentesis. Topical administration of 0.1% diclofenac significantly reduced aqueous humor flare at 8 and 26 hours after paracentesis. Topical administration of 0.1% dexamethasone and 0.03% flurbiprofen did not significantly decrease flare at any time point. There were significant differences in intraocular pressures between NSAID-treated eyes and untreated contralateral eyes. Conclusions and Clinical Relevance-Topical administration of 1% prednisolone and 0.1% diclofenac significantly reduced intraocular inflammation in cats with paracentesis-induced uveitis. Topical administration of 1% prednisolone or 0.1% diclofenac may be appropriate choices when treating cats with anterior uveitis. Topical administration of diclofenac and flurbiprofen should be used with caution in cats with a history of ocular hypertension.