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Abstract

OBJECTIVE

To characterize uropathogenic Escherichia coli (UPEC) in cases of clinical feline urinary tract infection (UTI) and subclinical bacteriuria and investigate the in vitro effects of E coli strain Nissle 1917 on isolate growth.

ANIMALS

40 cats with positive E coli culture results for urine collected during routine evaluation.

PROCEDURES

Characterization of UPEC isolates was performed by PCR-based phylotype analysis and serotyping. Nissle 1917 effects on growth inhibition and competitive overgrowth against UPEC isolates were evaluated in vitro using a plate-based competition assay.

RESULTS

Feline phylogroups were similar to previous human and feline UPEC studies, with most of the isolates belonging to phylogroup A (42.5%), B2 (37.5%), and D (15.0%). Fifty-two percent of isolates were found to be resistant to antimicrobials, with 19% of these being multidrug resistant (MDR). Nissle 1917 adversely affected the growth of 82.5% of all isolates and 100% of MDR isolates in vitro. The median zone of inhibition was 3.33 mm (range, 1.67 to 10.67 mm). Thirteen isolates were affected via competitive overgrowth and 20 via growth inhibition.

CLINICAL RELEVANCE

UPEC isolates from cats were similar in phylogroup analysis to human and dog isolates. The in vitro effects of Nissle 1917 on UPEC warrant additional studies to determine if similar results can be duplicated in vivo.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate the enhancement accuracy of a triple-phase abdominal CT angiography (CTA) protocol in dogs and explore the patient, scan, and contrast parameters associated with accuracy of enhancement.

ANIMALS

233 client-owned dogs that underwent routine abdominal CTA.

PROCEDURES

During each CTA study, the subjective timing accuracy (early, ideal, late) of the 3 obtained vascular phases (arterial, venous, delayed) was scored by consensus (2 reviewers) at 4 target organs (liver, pancreas, left kidney, and spleen). These scores were evaluated for statistical associations with 21 study variables (patient, scan, and contrast medium). The objective enhancement (HU) for each target organ was also compared statistically with subjective timing accuracy scores and the study variables.

RESULTS

The study protocol performed best for the pancreas, moderately for the liver, and worse for the spleen and left kidney. Measurements of scan length and time were associated positively with phase lateness for most target organs and phases. Increased heart rate was the most significant patient factor associated positively with phase lateness within the liver (all phases), pancreas (arterial and venous phases), and kidney (arterial phase). Contrast medium variables were less associated with timing accuracy in this protocol. Objective enhancement (HU) correlated poorly with subjective phase timing accuracy and study variables.

CLINICAL RELEVANCE

Scan time, scan length, and heart rate were the predominant variables contributing to lateness in this canine abdominal CTA protocol. The findings of this exploratory study may aid in protocol adjustment and choice of included anatomy for dogs undergoing routine abdominal CTA.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To collect kinetic gait reference data of dogs of 2 breeds in their growth period during walking and trotting gait, to describe their development, and to investigate the weight support pattern over time.

ANIMALS

8 Foxhound-Boxer-Ingelheim Labrador Retriever mixed breeds and 4 Beagles.

PROCEDURES

Ground reaction force variables (GRFs), peak vertical force and vertical impulse, and temporal variables (TVs) derived therefrom; time of occurrence; and stance times were collected. Body weight distribution (BWD) was evaluated. Six measurements, each containing 1 trial in walking and 1 trial in trotting gait, were taken at age 10, 17, 26, 34, 52, and 78 weeks. The study period started July 17, 2013 and lasted until October 7, 2015. Area under the curve with respect to increase was applied. The difference of area under the curve with respect to increase values between breeds and gaits was analyzed using either the t test or the Mann-Whitney test. Generalized mixed linear models were applied.

RESULTS

Significant differences in gait and breed comparisons were found. Growing dogs showed a forelimb-dominated gait. The development of GRF and TV values over the study period were described.

CLINICAL RELEVANCE

Reference values for GRFs, TVs, and BWDs in growing dogs were given. A cranial shift in weight support over time was found during trotting gait. Smaller, younger dogs walked and trotted more inconsistently.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To quantify the translation and angular rotation of the distal sesamoid bone (DSB) using computed tomography (CT) and medical modeling software.

SAMPLE

30 thoracic limbs from equine cadavers.

PROCEDURES

Partial (n = 12), full (8), and matched full and subsequently transected (10) thoracic limbs were collected. Bone volume CT images were acquired in three positions: extension (200° metacarpophalangeal angle), neutral (180°), and maximal flexion (110°). Mean translation and angular rotation of each DSB were recorded. Differences were determined with two-way ANOVA and post hoc Tukey’s tests for pairwise comparisons; P value was set at < 0.05.

RESULTS

Dorsal translation was significant during extension (1.4 ± 0.4 mm full limbs and 1.3 ± 0.2 mm partial limbs, P < 0.001). Distal translation was significant during extension (1.9 ± 0.4 mm full and 1.1 ± 0.4 mm partial) and flexion (5.4 ± 0.7 mm full and 6.22 ± 0.6 mm partial, P < 0.001). Rotation was significant (P < 0.001) about the mediolateral axis during extension (17.1° ± 1.4°) and flexion (2.6° ± 1.3°). Translation and rotation of the DSB were significantly different (P < 0.001) between full and partial limbs.

CLINICAL RELEVANCE

This study provides the first quantification of translation and angular rotation of the DSB within the equine hoof. Partial limbs had significantly reduced movement compared to full limbs, suggesting that transection of flexor tendons alters distal thoracic limb kinematics. Further studies are required to determine if pathologic changes in the podotrochlear apparatus have an impact in clinical lameness outcomes.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To examine the pharmacokinetics and ex vivo pharmacodynamics of oral firocoxib administration in New Zealand White rabbits (Oryctolagus cuniculus).

ANIMALS

6 healthy New Zealand White rabbits.

PROCEDURES

Pharmacokinetics were determined from plasma concentrations measured via ultra performance liquid chromatography-tandem mass spectrometry after oral administration of firocoxib at a dose of 3.74 to 4.20 mg/kg. Pharmacokinetic analysis was performed using non compartmental methods. Pharmacodynamics of firocoxib were evaluated by measuring plasma concentrations of thromboxane and prostaglandin via ELISAs as surrogate markers of cyclooxygenase enzyme isoform inhibition.

RESULTS

The terminal rate constant was 0.07 hours (range, 0.05 to 0.11 h). The mean maximum concentration (Cmax) and time to Cmax were 0.16 µg/mL and 3.81 hours (range, 2.0 to 8.0 h), respectively. Mean residence time was 15.02 hours. Mean elimination half-life was 9.12 hours. For the pharmacodynamic analysis, firocoxib administration did not demonstrate a significant difference between any time point for prostaglandin E2 and only a significant difference between 24 and 48 hours for thromboxane B2.

CLINICAL RELEVANCE

Although the pharmacokinetic research supports that plasma firocoxib concentrations that would be therapeutic in dogs are achieved in rabbits, the pharmacodynamic results do not demonstrate a significant difference in levels of cyclooxygenase-2 inhibition, which indirectly reflects the anti-inflammatory effects of the drug. Further pharmacodynamic studies and multidose studies are warranted to determine the efficacy and safety of this drug in rabbits.

Open access
in American Journal of Veterinary Research
Author: Mathieu Spriet

Abstract

Positron emission tomography (PET) has established itself as a pertinent tool in equine musculoskeletal imaging in the last few years. With the ability to provide functional information regarding both bone and soft tissues, PET has found several clinical applications in horses. PET is currently used in horses as an enhanced bone scan, providing high-resolution 3-dimensional information, in particular for imaging of the racehorse fetlock. Combined with CT and MRI, PET is particularly pertinent in horses for the assessment of subchondral bone and enthesis. The development of a dedicated PET scanner to image the distal limb of horses with standing sedation led to new applications, where PET is used as a first-line advanced imaging tool, in particular for foot, fetlock, and tarsal imaging. A complimentary clinical review of when to seek advanced imaging in equine athletes can be found in the companion Currents in One Health by Garrett in the July 2022 issue of the Journal of American Veterinary Medical Association. The clinical use of PET in human medicine remains mainly focused on oncological imaging; however, numerous small-scale clinical studies have demonstrated valuable applications for musculoskeletal imaging. These include assessment of foot and ankle pain, osteoarthritis of the knee and hip, osteoporosis, response to bisphosphonates, and chronic osteomyelitis. The use of musculoskeletal PET in dogs remains quite limited, but a few studies have recently been published and clinical interest is growing. The available research data and clinical applications between horses, humans, and dogs are currently quite disparate, but all suggest great promises for earlier and more accurate clinical diagnosis, as well as better understanding of pathophysiology and response to treatment. Translating knowledge from a species to another will undoubtedly help further growth of musculoskeletal PET.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare the analgesic efficacy of grapiprant to carprofen for the treatment of postoperative pain and inflammation in dogs following ovariohysterectomy.

ANIMALS

12 purpose-bred adult sexually intact female Beagles.

PROCEDURES

Dogs were randomly assigned to 1 of 2 treatment groups: grapiprant (2 mg/kg, PO; n = 6) or carprofen (4.4 mg/kg, PO; n = 6), 1.5 hours prior to ovariohysterectomy (OVH) and every 24 hours afterward for 3 total doses. An ultrafiltration probe was placed within the OVH incision to collect interstitial fluid (ISF). Pain and inflammation were assessed by masked investigators via mechanical nociceptive threshold testing and the short form of the Glasgow Composite Pain Scale before drug administration and at multiple time points for 72 hours following dosing and surgery. ISF samples were collected at the same time points to assess prostaglandin E2 concentrations at the site of inflammation.

RESULTS

In both groups, pain scale scores were highest in the immediate postoperative period and decreased over time. In both treatment groups, there were significant (P = 0.003) differences in mechanical nociceptive threshold results over time when compared with baseline, but there was no difference between groups. Prostaglandin E2 concentrations in ISF were higher in dogs receiving grapiprant compared with carprofen (P < 0.001). One dog in the carprofen group required rescue analgesia.

CLINICAL RELEVANCE

Results of this preliminary study suggested both carprofen and grapiprant may be effective for postoperative pain following OVH in dogs; however, additional studies are warranted to determine grapiprant’s effectiveness in a larger and more diverse population of dogs.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To perform a qualitative analysis of the distribution of µ- and κ-opioid receptor mRNA in the forebrain and midbrain of budgerigars (Melopsittacus undulatus).

SAMPLE

8 brains of male budgerigars.

PROCEDURES

Custom-made RNA hybridization probes (RNAscope; Advanced Cell Diagnostics Inc) were used for fluorescent in situ hybridization (FISH) assays performed on selected fresh frozen prepared sections of brain tissue to identify µ- and κ-opioid receptor mRNA.

RESULTS

There was κ-opioid receptor mRNA present in the nucleus dorsomedialis posterior thalami, lateral striatum, mesopallium, tractus corticohabenularis et corticoseptalis, griseum et fibrosum, stratum griseum centrale, medial striatum, and area parahippocampalis. There was µ-opioid receptor mRNA present in the stratum griseum centrale, stratum opticum, dorsomedialis posterior thalami, area parahippocampalis, medial striatum, and nidopallium intermedium.

CLINICAL RELEVANCE

Consistent with previous studies in pigeons and domestic chicks, κ-opioid receptors were more abundant than µ-opioid receptors in the samples of the present study. The results of this study may also help explain the hyperexcitability or lack of response that can occur with administration of pure µ-opioid receptor agonists, but not κ-opioid receptor agonists. This study was not quantitative, so further research should endeavor to compare the various regions of the brain using FISH technology.

Open access
in American Journal of Veterinary Research
Author: Kathryn Meurs

At NC State, we are improving the world of veterinary medicine in numerous and exciting ways. Here are four areas where we are breaking new ground.

CONQUERING PAIN. Like humans, animals experience chronic pain from a variety of conditions such as arthritis, back issues, and nerve damage. In veterinary medicine, however, chronic pain is not well understood and often underdiagnosed. The first step to a breakthrough is establishing methods to measure pain. The work of B. Duncan X. Lascelles, professor of translational pain research, has helped us learn how to reliably measure chronic pain in naturally occurring chronic

Open access
in American Journal of Veterinary Research

The new 2022 AVMA Pet Ownership and Demographics Sourcebook  examines types of pet owners, spending on veterinary care, veterinary visits, and client satisfaction.

Full access