American journal of veterinary research最新文献

Electron microscopy is an important imaging tool to identify ultrastructural abnormalities of the myocardium, diagnose certain diseases, and expand the understanding of mechanisms of cardiovascular disease processes. Transmission electron microscopy (TEM) is still an important part of human cardiovascular pathology, but its use in veterinary medicine has become uncommon. Even in patients with minimal histopathological changes on light microscopy, there can be important ultrastructural findings that help to achieve a diagnosis. In addition, TEM can be valuable for research by shedding light on underlying mechanisms or investigating new forms of cardiomyopathies. This review highlights the importance of TEM, details normal and pathological ultrastructural findings, and provides insight into clinical and research uses. We also provide tips on tissue preparation, processing, and analysis that are key to successful use of this valuable tool.

Objective: To provide a video tutorial illustrating how to place a hemodialysis catheter in the external jugular vein of a dog via a percutaneous modified Seldinger approach.

Animals: Any dog requiring vascular catheter placement for extracorporeal therapy.

Methods: The patient is placed under general anesthesia in left lateral recumbency. The fur is clipped, and the skin over the right lateral neck is aseptically prepared. The operators are wearing full protective barriers. A skin incision with a No. 11 blade is made over the jugular vessel, and an 18-gauge over-the-needle catheter is used for vascular access. With the use of fluoroscopic guidance, a guidewire is passed through the peripheral catheter and into the caudal vena cava. The peripheral catheter can then be removed and a dilator passed over the guidewire to stretch the size of access into the vein. The dilator is removed, and the catheter is passed over the guidewire. Fluoroscopy is used to confirm placement of the catheter tip, and both lumens are aspirated to test blood flow. The catheter lumens are then flushed with saline and capped. The catheter can then be sutured in place.

Results: An 11-French X 20-cm silicone hemodialysis catheter is placed in the right external jugular vein of a dog.

Clinical relevance: Dialysis catheter placement is a key step in providing extracorporeal treatment for veterinary patients.

Objective: To investigate the pathological causes of late embryonic death in ostrich hatcheries and their economic impact in Egypt.

Methods: The study was conducted from February 2023 through December 2024. The pathological causes, microbiological analysis, and financial impact of late embryonic deaths across 9 ostrich hatcheries in Egypt were investigated.

Results: A total of 1,250 fertile ostrich eggs failed to hatch. The highest mortality rate was observed in Ismailia at 28.88%, whereas the lowest was recorded in Giza at 15.62%. The cumulative economic loss across all hatcheries was estimated at 1,750,000 Egyptian pounds. The bacterial infections were the leading cause of late embryonic death, accounting for 813 cases (65.04%), followed by improper incubation conditions, such as elevated temperatures (22.48%), edema (5.12%), malpositioning (3.6%), improper egg turning (2.56%), and fungal infections (1.2%). The most commonly isolated bacterial were Enterococcus spp, Salmonella spp, Proteus spp, and Klebsiella spp. Gross post mortem examination of dead-in-shell embryos revealed consistent lesions, including anasarca, SC and visceral congestion, unabsorbed yolk sacs, and malpositioning. Microscopic evaluation of embryos that died due to bacterial infections revealed severe inflammatory changes in multiple organs.

Conclusions: The infectious and noninfectious factors contribute to late embryonic mortality in ostrich hatcheries, with bacterial contamination being the dominant cause. The embryos that died revealed severe pathological lesions in various organs.

Clinical relevance: The study highlights the urgent need for improved hatchery hygiene, biosecurity, and strict control of incubation conditions to enhance hatchability and reduce economic losses in the ostrich industry in Egypt.

Orthobiologics rich in alpha-2-macroglobulin (A2M) are being used with increasing frequency to treat equine and human osteoarthritis (OA). The glycoprotein is concentrated from whole blood, typically prepared by a commercial device, and is administered IA with the goal of ameliorating inflammation and associated pain. In recent years, numerous investigations have elucidated A2M's mechanism of action and its effects on joint cells; however, none have used the horse as a model nor have they investigated the commercially available kit for equine orthobiologic preparation, Alpha2EQ. This narrative review presents the most pertinent work on A2M, which supports its current clinical use as an OA treatment. Alpha-2-macroglobulin has been studied in a variety of preclinical models, in vivo, and in clinical patients. As a naturally occurring and potent protease inhibitor, A2M acts to regulate key components of the OA inflammatory cascade, from cytokines and chemokines, which propagate synovitis, to disintegrins and metalloproteinases that degrade the cartilage extracellular matrix. Three main mechanisms of action contribute to A2M's modulation of joint inflammation and concomitant OA progression across species: the bait-and-trap mechanism, direct binding interactions, and regulation of gene expression. In vivo, A2M treatment results in improved histopathology scores, gait improvement in animals, and improved patient-reported outcomes in people. Though substantial evidence exists for A2M's anti-inflammatory effects and role in OA treatment, further studies will be required to elucidate the mechanisms of the equine orthobiologic.

Objective: To assess the thoughts and feelings of faculty regarding a new mentoring program.

Methods: An online survey was developed and sent to faculty members through institutional email at the beginning (September) and end of the school year (May) of initiation of a faculty-student mentorship program.

Results: In September and May, faculty felt confident in their ability to provide mentorship for students. Faculty believe that individual meetings are more effective than group meetings for mentoring students.

Conclusions: Overall, faculty confidence in mentoring increased over time, but there were concerns about the program's structure, engagement, and effectiveness. Faculty valued individual mentoring more than group mentoring and expressed the need for better administrative support and clearer guidelines.

Clinical relevance: Providing faculty with clear objectives and practical guidance may improve faculty confidence, engagement, and feelings of efficacy in veterinary student mentoring programs. Effective mentoring can lead to better-prepared graduates who are more confident, skilled, and capable of handling the complexities of their future clinical roles. This, in turn, can improve patient care and outcomes.

Objective: To obtain pharmacokinetic data of a single dose of buprenorphine administered to ferrets via IM or oral transmucosal (OTM) routes.

Methods: In this experimental pharmacokinetic study, domestic ferrets in a laboratory setting were randomly assigned to a treatment group of either 0.04 mg/kg of buprenorphine (0.3 mg/mL) administered IM or OTM. After a 10-day washout period, each ferret received buprenorphine via the other route of administration. Blood was collected prior to and 5, 10, 30, 60, 90, 120, 240, 360, 480, and 720 minutes following drug administration for pharmacokinetic analysis. Ferrets were excluded from the study if their vascular access buttons became nonfunctional before the end of the study. Ferrets were monitored for side effects, including increased salivation, decreased defecation, and sedation.

Results: Data from 8 female domestic ferrets were used to calculate pharmacokinetic profiles. Mean maximum plasma concentration and time to maximum concentration were 5.03 ng/mL and 0.13 hours, respectively, for the IM route of administration. The mean terminal half-lives were 2.77 and 0.715 hours for IM and OTM routes of administration, respectively. Mild sedation was noted in most animals regardless of route of administration.

Conclusions: Based on effective buprenorphine plasma concentrations in dogs (0.6 ng/mL), OTM buprenorphine at a dose of 0.04 mg/kg likely provides short-term analgesia to ferrets when compared to the IM route, but administration via either OTM or IM route appears safe.

Clinical relevance: OTM and IM buprenorphine both reached theoretically analgesic plasma levels in ferrets, but a short half-life may limit clinical applications of the OTM route.

Objective: To evaluate the agreement between linear deflection oscillometry (LDO) and Doppler ultrasonography (DU) for measuring systolic arterial pressure (SAP) in nonsedated dogs.

Methods: Prospective, cross-sectional study, conducted at 2 veterinary teaching hospitals. The study included nonsedated, hospitalized dogs classified by DU SAP as normotensive (90 to 160 mm Hg), hypotensive (< 90 mm Hg), or hypertensive (> 160 mm Hg). The SAP was measured using both DU and LDO.

Results: 60 dogs were included (29 normotensive, 17 hypotensive, 14 hypertensive). Passing-Bablok regression demonstrated a significant systematic (intercept, 17.6; 95% CI, 7.4 to 29.7; P < .01) and proportional bias (slope, 0.81; 95% CI, 0.71 to 0.92; P < .01), indicating progressively larger differences between DU and LDO at higher SAP values. Bland-Altman analysis showed a bias of -3.0 ± 8.49 mm Hg (limits of agreement [LoA], -19.66 to 13.64) in hypotensive dogs, 1.66 ± 11.96 mm Hg (LoA, -21.8 to 25.1) in normotensive dogs, and 26.7 ± 26.17 mm Hg (LoA, -24.77 to 78.2) in hypertensive. Receiver operating characteristic analysis suggested LDO thresholds of 93 mm Hg for DU SAP < 90 mm Hg (AUC, 0.994; P < .0001) and 143 mm Hg for DU SAP > 160 mm Hg (AUC, 0.891; P < .0001).

Conclusions: LDO and DU demonstrated acceptable agreement in normotensive and hypotensive dogs but weak concordance in hypertensive.

Clinical relevance: LDO may be a practical alternative to DU in normotensive and hypotensive states, but caution is warranted in hypertensive patients.

Objective: To identify the race- and horse-level factors affecting stride parameters during Thoroughbred races in Japan.

Methods: Global Navigation Satellite System sensors were attached to 921 horses (1,189 starts) participating in 83 races, with distances ranging from 1,000 to 1,800 m, held from April through July 2024. Stride frequency and stride length were calculated from speed spectrograms at 3 racing phases (phase 1, 200 m after gate open; phase 2, 10 m after reaching the final straight stretch; and phase 3, 130 m before the finishing line). Additionally, 10 variables (race distance, surface type and condition, sex, age, finishing position, racing class, racecourse, body mass, and speed) were analyzed using a multivariable linear mixed model.

Results: Mean (± SD) stride frequency, stride length, and speed were 2.36 ± 0.12 Hz (ie, strides/s), 7.30 ± 0.39 m, and 17.2 ± 1.15 m/s across all phases, respectively. Faster speed, geldings, longer race distance, and greater body mass were associated with longer stride length. Stride length was 0.11 m shorter on dirt than turf during phases 2 and 3 (P < .01) but not phase 1. The conditional R2 of the final model was 0.76, and the marginal R2 (ie, only fixed effects considered) was 0.55.

Conclusions: Moderate interhorse variability in stride parameters was found. In particular, racing phase and surface type affect stride parameters.

Clinical relevance: Racing phase, surface type, race distance, sex, and body mass in addition to speed should be considered when using stride parameters to evaluate performance and predict injury.

Objective: To manufacture and characterize a modified niclosamide stearate (NS) prodrug therapeutic (mNSPT) for use in a small clinical trial in a metastatic canine osteosarcoma (OS) model.

Animals: 10 dogs that presented for treatment of nondetectable metastatic OS underwent resection of primary tumors prior to systemic therapy. Four cycles of IV carboplatin (300 mg/m2, IV, q 3 wk) followed by 4 cycles of the experimental mNSPT (10 mg/kg, IV, weekly). Posttreatment surveillance included physical examination and thoracic radiographs every 3 months for 2 years. Samples for pharmacokinetic analysis were taken at the end of the 0.5- to 1-hour IV infusion of the mNSPTs and followed for 2 hours.

Clinical presentation: The NS average concentration at the end of infusion was 134.88 ± 13.32 μg/mL; the average area under the curve was 211.62 ± 27.89 h·µg/mL. The niclosamide concentration at the end of infusion was 23.11 μg/mL ± 3.77 μg/mL, and the area under the curve was 27.52 ± 5.92 h·µg/mL, well above the NSPT 0.75 μg/mL (1.27 μM) cell-effective concentrations for OS cells in culture. The average terminal half-life was 4.57 hours for NS and 3.23 hours for niclosamide. Three dogs developed metastatic disease on carboplatin and did not receive mNSPT. The median time to tumor progression and OS of the 7 treated dogs was 510 and 632 days, respectively, with 3 dogs living > 4 years.

Results: The results support further translational investigation of this novel therapeutic approach to OS treatment in a randomized, prospective phase III study in dogs and, if successful, ultimately in OS patients.

Clinical relevance: These results suggest that niclosamide-when transformed into the highly bioavailable NSPT-may have potential as a novel therapeutic agent for treating OS.