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Abstract

OBJECTIVE

To assess the presence of suspected pigment-associated deafness in North American yaks (Bos grunniens).

ANIMALS

12 North American yaks, including 11 with the homozygous piebald Royal pigmentation phenotype and 1 with the heterozygous piebald Trim phenotype.

PROCEDURES

Hearing was assessed using the brainstem auditory evoked response (BAER) on yaks restrained in the head gate of a grooming chute.

RESULTS

Five of the Royal yaks and the Trim yak had hearing in both ears. Six Royal yaks were affected; 3 were deaf in 1 ear and 3 were deaf in both ears.

CLINICAL RELEVANCE

For the first time, probable sensorineural deafness has been confirmed to be present in Royal yaks. The disorder is assumed to be congenital and associated with white pigmentation, based on the pattern of occurrence in other species.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine the pharmacokinetics of a solution containing cannabidiol (CBD) and cannabidiolic acid (CBDA), administered orally in 2 single-dose studies (with and without food), in the domestic rabbit (Oryctolagus cuniculus).

ANIMALS

6 healthy New Zealand White rabbits.

PROCEDURES

In phase 1, 6 rabbits were administered 15 mg/kg CBD with 16.4 mg/kg CBDA orally in hemp oil. In phase 2, 6 rabbits were administered the same dose orally in hemp oil followed by a food slurry. Blood samples were collected for 24 hours to determine the pharmacokinetics of CBD and CBDA. Quantification of plasma CBD and CBDA concentrations was determined using a validated liquid chromatography–mass spectrometry (LC-MS) assay. Pharmacokinetics were determined using noncompartmental analysis.

RESULTS

For CBD, the area under the curve extrapolated to infinity (AUC)0–∞ was 179.8 and 102 hours X ng/mL, the maximum plasma concentration (Cmax) was 30.4 and 15 ng/mL, the time to Cmax (tmax) was 3.78 and 3.25 hours, and the terminal half-life (t1/2λ) was 7.12 and 3.8 hours in phase 1 and phase 2, respectively. For CBDA, the AUC0–∞ was 12,286 and 6,176 hours X ng/mL, Cmax was 2,573 and 1,196 ng/mL, tmax was 1.07 and 1.12 hours, and t1/2λ was 3.26 and 3.49 hours in phase 1 and phase 2, respectively. Adverse effects were not observed in any rabbit.

CLINICAL RELEVANCE

CBD and CBDA reached a greater Cmax and had a longer t1/2λ in phase 1 (without food) compared with phase 2 (with food). CBDA reached a greater Cmax but had a shorter t1/2λ than CBD both in phase 1 and phase 2. These data may be useful in determining appropriate dosing of cannabinoids in the domestic rabbit.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare erythrocyte recovery by a cell salvage device between swab-washing by manual agitation or filtration.

SAMPLE

12 recently expired units of canine packed RBCs.

PROCEDURE

The packed RBC units underwent quality analysis before donation from a pet blood bank. Each unit was volume-expanded with anticoagulant and subsequently divided into 2 equal aliquots used to soak surgical swabs before washing. Two different swab-washing techniques were evaluated—standard swab-washing–manual agitation (SW-MA) and swab-washing–filtration (SW-F)—with a novel prototype device. The resulting bloody fluid was processed using the Cell Saver Elite Autotransfusion System (Haemonetics). The volume, manual PCV, CBC, and RBC mass, calculated as the product of the volume and PCV, were measured before and after salvaging. Last, the RBC mass recovery was recorded as a percentage.

RESULTS

The RBC mass recovered from SW-MA and SW-F averaged 85.73% and 83.99%, respectively. There was no significant difference in RBC recovery between the 2 methods (P = .52).

CLINICAL RELEVANCE

SW-MA and SW-F recovered a similar quantity of RBCs from blood-soaked swabs in an ex vivo setting.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine whether muscle-sparing laryngoplasty results in fewer changes in swallowing function compared to standard surgical treatment for laryngeal paralysis.

ANIMALS

12 clinically normal sexually intact male Beagles.

PROCEDURES

Group A dogs (n = 4) had a standard approach to the larynx, with left arytenoid cartilage lateralization. Group B dogs (n = 4) had a muscle-sparing laryngoplasty performed with the thyropharyngeus muscle fibers bluntly separated, and the cricoarytenoideus dorsalis muscle spared. Pre- and 24-hour postoperative fluoroscopic swallowing studies were performed and graded. Larynges were harvested after humane euthanasia, and glottic area was measured. Group C dogs (n = 4) acted as controls, with surgical dissection ending lateral to the thyropharyngeus muscle, arytenoid lateralization not performed, and the dogs not euthanized. The study was performed between October 15, 2011 and May 15, 2021.

RESULTS

Changes in pharyngeal and upper esophageal sphincter function were not detected in any group. There was no difference in glottic area between treatment groups. Aspiration of liquid was not a consistent finding. Two dogs in each treatment group developed moderate to severe cervical esophageal paresis. This did not occur in control dogs.

CLINICAL RELEVANCE

We found no evidence to support our hypothesis that muscle-sparing laryngoplasty results in less severe changes in swallowing function compared to a standard technique. The cervical esophageal paresis identified in both treatment groups could increase the risk of postoperative aspiration pneumonia in dogs treated for laryngeal paralysis via a lateral approach to the larynx. Further study to determine the frequency, cause, and duration of esophageal dysfunction is warranted.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To create a model of transient unilateral laryngeal paralysis (LP) that will allow the study of cricoarytenoideus dorsalis dysfunction and a method for quantification of varying degrees of LP in dogs.

ANIMALS

5 castrated male research Beagles.

PROCEDURES

Between January and February 2018, dogs were anesthetized and instrumented with a laryngeal mask airway and a flexible endoscope to record the rima glottidis. The left or right recurrent laryngeal nerve (RLn) was localized using ultrasonography and electrical stimulation, then conduction blockade was induced with perineural lidocaine. The normalized glottal gap area (NGGA) was measured before and every 15 minutes after the block. Inspired 10% carbon dioxide (CO2) was administered for 1 minute at each sampling time. The inspiratory increase in NGGA (total and each side) was measured at peak inspiration. The change in hemi-NGGA for the control side versus the anesthetized side was evaluated with a mixed-effect model.

RESULTS

During CO2 stimulation, the increase in inspiratory hemi-NGGA was consistently less (P < .001) for the treated side (–8% to 13%) versus the control side (49% to 82%). A compensatory increase (larger than at baseline) in the control hemi-NGGA was observed. The total NGGA remained unaffected.

CLINICAL RELEVANCE

Unilateral local anesthesia of the RLn produced transient unilateral LP with a compensatory increase in the hemi-NGGA for the contralateral side. This model could facilitate the evaluation of respiratory dynamics, establishment of a grading system, and collection of other important information that is otherwise difficult to obtain in dogs with LP.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To identify and characterize the gross and histological lesions associated with air pollution in the lungs of dogs from various locations in Trinidad.

ANIMALS

56 fresh lungs were obtained from already euthanized adult dogs collected from different locations in Trinidad at the Trinidad and Tobago Society for the Prevention of Cruelty to Animals.

PROCEDURES

Lung specimens were examined grossly and tissue samples were taken for routine histologic examination.

RESULTS

Histological examination showed that 51.8% of the dogs had evidence of anthracosis. Dogs with anthracosis had greater median lesion scores compared to dogs without anthracosis (P = .022). There was no association between the presence of anthracosis and any other lesion in this study (P > .05).

CLINICAL RELEVANCE

There was evidence that dogs with anthracosis had a greater degree of nonspecific lung histologic lesions. Using the dog as a sentinel model for human exposure in Trinidad, our findings indicate that environmental air pollution may also have an effect on the respiratory health of the human population. It is important for the public to be aware of air pollution, and the government of Trinidad and Tobago should develop an intervention protocol along with veterinary and human medical epidemiologists to reduce air pollution in the country.

Open access
in American Journal of Veterinary Research

OBJECTIVE

To evaluate pulmonary vein (PV)-to-pulmonary artery (PA) ratios obtained in healthy dogs by means of various CT protocols, accounting for the effects of the respiratory phase and contrast agent used.

ANIMALS

10 healthy Beagles.

PROCEDURES

Before and after contrast medium (600 mg iodine/kg) was injected IV, thoracic CT was performed with a positive-pressure breath-hold (inspiratory phase) and at the end of expiration (expiratory phase). After CT scanning, echocardiography was performed, and an optimized right parasternal long-axis view was obtained for measurement of PV and PA diameters. The PV and PA diameters were measured subsequently for each CT protocol.

RESULTS

Mean ± SD PV:PA values obtained from pre- and postcontrast inspiratory CT were 1.058 ± 0.072 and 1.020 ± 0.053, respectively, which were comparable to the echocardiographic value (P > .05). Mean PV:PA values obtained with pre- and postcontrast expiratory CT were 1.259 ± 0.094 and 1.239 ± 0.066, respectively, which were significantly (P = .005) greater than inspiratory CT measurements. There was a significant (r > 0.5, P < .05) linear relationship between PV:PA values obtained with pre- and postcontrast inspiratory CT and echocardiography.

CLINICAL RELEVANCE

PV:PA could be measured with thoracic CT in a manner similar to that for echocardiography. However, PV:PA values measured with expiratory CT were different from previously reported values. Therefore, the respiratory phase should be considered when evaluating pulmonary vascular size through CT, and measurements with the inspiratory CT protocol would be more accurate.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare osteoarthritis scores assigned through radiographic evaluation of 18 anatomic regions in the elbow joint with scores assigned through evaluation of 3-D maximum intensity projection (MIP), 3-D surface rendering (TSR), and multiplanar reconstructed (MPR) CT images, and to evaluate intraobserver and interobserver agreement of radiographic and CT scoring.

SAMPLE

Radiographic and CT images of 39 elbow joints in 20 dogs.

PROCEDURES

Images were anonymized and graded independently by 5 observers. One observer graded 12 elbow joints 3 times. Intraobserver consistency and repeatability, interobserver agreement, consistency among methods, and bias between methods were calculated.

RESULTS

The most severe changes were observed at the proximal aspect of the anconeal process, and the medial and cranial aspects of the medial coronoid process. Intraobserver consistency was moderate or better for 11/16 regions with MIP images, 11/16 regions with TSR images, 17/18 regions with MPR images, and 14/18 regions with radiographic images. Interobserver agreement was moderate or better for 5/16 regions with MIP images, 9/16 regions with TSR images, 12/18 regions with MPR images, and 6/18 regions with radiographic images. Mean scores from CT-based methods were higher than mean radiographic scores.

CLINICAL RELEVANCE

Assessments of osteoarthritis severity in the elbow joints of dogs obtained by examining radiographic images were generally consistent with assessments obtained by examining CT scans. MPR scores were more consistent and more comparable to radiographic scores than were MIP or TSR scores.

Open access
in American Journal of Veterinary Research

OBJECTIVE

To assess the safety and efficacy of the platelet-like nanoparticle (PLN), and to assess its safety in repeated administration.

ANIMALS

6 purpose-bred dogs.

PROCEDURES

The PLN was administered IV at 3 different doses using a randomized crossover design. Each dog received a full dose of 8 X 1010 particles/10 kg, half dose, and 10 times the dose, with a 14-day washout period between doses. Biochemical, prothrombin time, partial thromboplastin time, and fibrinogen analyses were performed at baseline and 96 hours postinfusion. A CBC, kaolin-activated thromboelastography, platelet function assay closure time, and buccal mucosal bleeding time were performed at baseline and 1, 6, 24, 48, 72, and 96 hours postinfusion.

RESULTS

No significant changes were observed over time in the thromboelastography parameters, closure time, and buccal mucosal bleeding time. After the administration of the half dose, hematocrit levels decreased significantly at 1, 6, 24, 48, and 96 hours, with all values within the reference range. The platelet count was decreased significantly at hours 1, 6, 24, 48, and 72 after administration of the half dose, with values less than the reference range at all hours but hour 72. No significant changes in serum biochemistry, coagulation panel, and fibrinogen were observed for all doses. No adverse events were noted during the first infusion. Three dogs experienced transient sedation and nausea after repeat infusion.

CLINICAL RELEVANCE

The PLN resulted in a dilution of hematocrit and platelets, and did not significantly alter hemostasis negatively. The safety of repeated doses should be investigated further in dogs.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To assess whether cardiac MRI or various biomarkers can be used to detect myocardial ischemia and fibrosis in dogs with cardiomegaly secondary to myxomatous mitral valve disease (MMVD).

ANIMALS

6 dogs with cardiomegaly secondary to naturally occurring stage B2 MMVD being treated only with pimobendan with or without enalapril and 6 control dogs with no cardiac disease. All dogs were ≥ 5 years old with no systemic illness.

PROCEDURES

Serum cardiac troponin I and concentrations were measured, and dogs were anesthetized for cardiac MRI with ECG-triggered acquisition of native T1- and T2-weighted images. Gadolinium contrast was administered to evaluate myocardial perfusion and late gadolinium enhancement (LGE). Mean T1 and T2 values and regions of LGE were measured with dedicated software. Extracellular volume (ECV) was estimated on the basis of Hct and T1 values of myocardium and surrounding blood. Subjective analysis for myocardial perfusion deficits was performed.

RESULTS

Dogs with MMVD had significantly (P = .013) higher cardiac troponin I concentrations than control dogs, but galectin-3 concentrations did not differ (P = .08) between groups. Myocardial fibrosis was detected in 4 dogs with MMVD and 3 control dogs; no dogs had obvious myocardial perfusion deficits. Native T1 and T2 values, postcontrast T1 values, and ECV values were not significantly different between groups (all P > .3).

CLINICAL RELEVANCE

Results suggest that some dogs with cardiomegaly secondary to MMVD may not have clinically relevant myocardial fibrosis.

Open access
in American Journal of Veterinary Research