American journal of veterinary research最新文献

Objective: To biomechanically evaluate the stability of internal fixation methods for femoral neck fractures in small-breed dogs. Furthermore, the possibility of replacing the headed screw with fully threaded headless cannulated screws in the fixation method was assessed.

Methods: The study was conducted from December 12, 2023, to February 7, 2024. A total of 18 femurs from 9 canine cadavers were used in this study. After a simple neck fracture was created, in group A (n = 6), the fracture was stabilized with three 1.1-mm parallel Kirschner wires (K-wires). In group B (n = 6), a 3.0-mm partially threaded cannulated screw and an antirotation pin were used. In group C (n = 6), a 2.5-mm fully threaded headless cannulated screw and an antirotation pin were used. A mechanical test was conducted to apply a single axial compressive load to the femoral head.

Results: 9 adult small-breed dogs weighing 3.6 to 8.3 kg (mean ± SD; 5.9 ± 1.6). The mean maximum failure load was highest in group C (495 ± 81 N), followed by group B (454 ± 50.4 N), and then group A (222 ± 21.6 N). Significant differences in maximum failure load were observed between groups A and B as well as groups A and C but not between groups B and C.

Conclusion: The use of fully threaded headless cannulated screws presents a promising method for internal fixation of canine femoral neck fractures.

Clinical relevance: To demonstrate the potential stability and reliability of fully threaded headless cannulated screws.

Objective: The goal of this study was to compare the accuracy of kinematic measurements obtained using the 2-D video-based kinematic motion analysis (KMA) software Kinovea (version 0.9.5; http://www.kinovea.org) with 3-D KMA in healthy dogs.

Methods: In this prospective study, 3-D marker-based KMA (VICON-Nexus, version 2.12.1, and Procalc, version 1.6; VICON Motion Systems Ltd) was performed on healthy dogs (body weight ≥ 20 kg; height at withers > 50 cm) walking on a treadmill (study period: November 2022). Simultaneously, dogs were video recorded by 1 smartphone (iPhone SE; Apple Inc) at a 1.50-m distance perpendicular to the shoulder (60 frames per second; 1,920 X 1,080 pixels) for KMA using Kinovea. Joint angle and joint angle velocity of the shoulder, elbow, carpus, hip, stifle, and tarsus were calculated for 6 synchronized gait cycles. Each gait cycle was divided into 10 increments. The difference between 3-D KMA and Kinovea was assessed for each parameter using robust linear mixed-effects models.

Results: 34 dogs were included. The estimated joint angle difference between 3-D KMA and Kinovea was less than 2° for all shoulder and elbow gait cycle increments. For the carpus, hip, stifle, and tarsus, the difference was less than 2° in 9, 5, 4, and 4 out of 10 gait cycle increments, respectively.

Conclusions: Kinovea provides accurate kinematic data for the shoulder and elbow of healthy dogs. Carpal, hip, stifle, and tarsal kinematics were less accurate.

Clinical relevance: The use of Kinovea for clinical and research purposes remains limited. Future Kinovea-based studies are needed to investigate the accuracy of carpal, hip, stifle, and tarsal kinematics.

Objective: To describe the development and maturation of equine proximal sesamoid bones (PSBs) in fetuses and young horses using radiography, microcomputed (micro)-CT, and histology.

Methods: A descriptive study. Forelimb PSBs from 12 equids ranging in age from 105 days of gestation to 540 days postgestation were evaluated. Radiography was used for preliminary assessment of metacarpophalangeal joint and PSB mineralization, and micro-CT imaging was performed to assess mineralized PSBs. Tissue volume, bone volume fraction, height, width, depth, trabecular thickness, and anisotropy were quantified from midplanar micro-CT sections in 3 dimensions. Midsagittal PSB histologic sections stained with H&E and Safranin O/Fast Green were used to determine the ratio of ossification center to cartilage template size and to describe the formation and development of the cartilage template, ossification center, spherical growth plate, articular cartilage, and entheses.

Results: Mineralization of equine PSBs is associated with cartilage canals and a spherical growth plate that undergoes endochondral ossification during the late gestation to early postgestational period. The apical, flexor, basilar, and articular ossification fronts demonstrate morphologic variability. Structural organization of the articular cartilage and entheses occurs concurrently with the development of an underlying plate of compact bone. At 540 days postgestation, the fibrocartilaginous entheses of the flexor cortex of the PSB had yet to mature.

Conclusions: Equine PSBs mineralize predominantly by endochondral ossification during the late gestation to early postgestational period. Mineralization precedes maturation of the articular cartilage and fibrocartilaginous entheses.

Clinical relevance: The postgestational maturation of the PSB and its surrounding tissues may predispose young horses to developing lesions at these sites, such as apical avulsion fractures, warranting further investigation.

Objective: The objective of this study was to determine the effects of repeated steam sterilization cycles on the biomechanical properties of surgical screws.

Methods: 42 3.5-mm and 42 2.0-mm self-tapping, cortical screws were divided into 3 groups per size and underwent autoclave sterilization for 1 (G1), 50 (G50), or 100 (G100) cycles and testing from August 2018 through June 2021. Sixty screws were then inserted into canine cadaver femurs, and biomechanical properties were measured, including peak insertional torque, torque to failure, and pullout strength, each normalized to cortical thickness. Scanning electron micrographs were taken from 24 screws, and images were blindly analyzed by 5 trained examiners.

Results: The mean normalized insertion torque for 3.5-mm screws was significantly different between G1 and both G50 and G100. The mean normalized torque to failure for 3.5-mm screws was significantly different between G1 and both G50 and G100. Axial pullout testing was found to be significantly different for 2.0-mm screws between G1 and G100. Scanning electron micrographs surface scoring identified a significant difference in 3.5-mm screws at the screw tip.

Conclusions: The results indicate that biomechanical changes occur with repeated steam sterilizations. Specifically, peak insertional torque and torque to failure are decreased with increased sterilizations for 3.5-mm screws, whereas 2.0-mm screws were altered in pullout testing after 100 sterilizations. It is suspected that numerous sterilizations negatively alter the physical-mechanical properties of certain screw sizes.

Clinical relevance: The biomechanical properties of the bone-implant interface could negatively be affected by multiple steam sterilizations during clinical setting.

Objective: To establish an echocardiographic technique in koi carp (Cyprinus carpio), compare cardiopulmonary parameters under manual restraint versus anesthesia, and provide a gross anatomical and histologic cardiac description.

Methods: A randomized, crossover echocardiography study was performed in 40 clinically healthy adult, unknown sex, privately owned koi carp on May 10 and 11 through June 26 and 27, 2021. Echocardiography was examined for each koi under manual restraint and isoeugenol at 50 ppm, with 3 measurements per examination performed by a radiologist and cardiologist. Two koi were euthanized for gross anatomic and histologic cardiac evaluation.

Results: Mean ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were significantly lower, mean heart rate (HR) was significantly higher, and opercular rate (OPR) was decreased significantly in anesthetized compared to manually restrained koi. Poor reproducibility for EF and SV was observed.

Conclusions: Echocardiography was feasible in both manually restrained and anesthetized koi; however, this technique may best be applied to monitoring trends over time in individual fish due to low reproducibility. Significant differences in multiple cardiopulmonary parameters, including HR, EF, SV, CO, and OPR, were present between manually restrained and anesthetized koi. A gross anatomic and histologic cardiac description is provided for this species to pair with the echocardiographic images.

Clinical relevance: This study provides the first description of echocardiography, cardiac gross anatomy, and histology in koi. The results support echocardiography as a safe and practical noninvasive diagnostic for cardiac assessment in koi under both manual restraint and anesthesia.

Objective: To evaluate the in vivo spread of iodinated contrast following injections in the transversus abdominis plane (TAP) and rectus sheath in anesthetized dogs via computed tomography. Secondarily, the time of performing each block was compared.

Animals: 6 adult, purpose-bred Beagles.

Methods: In a prospective crossover study, dogs were administered injections either in the rectus sheath or transversus abdominis fascial plane in the same manner as a rectus sheath block (RSB) or TAP block using dilute iodinated contrast. Computed tomography scans were performed immediately following injection (time [T]-0) and at 3, 9, 18, and 30 minutes postinjection. Data regarding the spread in the cranial-caudal and lateral directions and time to perform the injections were compared between the 2 techniques using paired or 2-sample t tests.

Results: There was significantly greater spread in the cranial-caudal direction in the RSB group (62.9 ± 6.4 mm vs 54.8 ± 6.8 mm at T30; P = .009), whereas spread in the lateral direction was greater in the TAP group (37.3 ± 3.0 mm vs 48.6 ± 6.1 mm at T30; P < .0001). The RSB injection was performed in a more time-efficient manner than TAP injection (48.2 ± 3.2 seconds vs 82.3 ± 8.7 seconds; P = .03).

Conclusions: In living subjects, RSB injections resulted in greater cranial-caudal spread while TAP injections resulted in greater lateral spread. Rectus sheath block injections were performed in a more time efficient manner compared to a single point TAP injection in anesthetized dogs.

Clinical relevance: The RSB was performed in a more time-efficient manner and would likely result in greater coverage of the ventral midline. The TAP block would likely result in more significant regional anesthetic coverage of the lateral abdominal wall. Further studies are required to determine the degree of the clinical significance of these results.

Objective: To investigate whether liver compression (LC) could increase stroke volume (SV) by more than 15% in healthy, anesthetized dogs with hypovolemia and suggest LC as a novel method to evaluate fluid responsiveness.

Animals: 6 healthy Beagles.

Methods: This prospective, nonrandomized experimental study was conducted from November 2023 to February 2024. The dogs were anesthetized with isoflurane and mechanically ventilated under neuromuscular blockade. After instrumentation, the dogs underwent the following 4 experimental stages in a sequential, nonrandomized manner: stage 1, baseline; stage 2, 30% withdrawal of circulating blood volume; stage 3, 50% infusion of the collected blood; and stage 4, the remaining 50% infusion of the collected blood. At each stage, SV via pulmonary artery thermodilution and hemodynamic variables were measured before, during, and after the LC.

Results: In stage 2, LC significantly increased mean SV by 30%, from 6.9 to 9 mL/beat. Simultaneously, LC significantly increased mean arterial pressure by 11 mm Hg and mean central venous pressure by 2 mm Hg, while pulse pressure variation significantly decreased from 28% to 22%. In stages 1, 3, and 4, LC did not significantly change mean SV, mean arterial pressure, and pulse pressure variation; however, mean central venous pressure significantly increased during stage 3.

Clinical relevance: This study demonstrates that LC at 22 mm Hg for 1 minute could increase SV more than 15% in anesthetized, hypovolemic dogs and LC could be used as a novel method to evaluate fluid responsiveness.

Urothelial carcinoma (UC) is the most common urogenital cancer in dogs. With early diagnosis, the disease can be controlled, to reduce progression of disease, in most dogs with a good quality of life. MicroRNAs (miRNAs) have been identified as a potential diagnostic and prognostic tool due to their stability and presence in both bodily fluids and tissues. MiRNAs have been frequently researched in human medicine and human UC; however, few manuscripts regarding miRNAs in canine UC are available. A search was performed on both PubMed and Google Scholar evaluating original research manuscripts with experimentally validated results for the terms "canine" or "dog"; "urothelial carcinoma," "bladder cancer," "transitional cell carcinoma," "TCC," "MIBC," "IMBUC," or "BLCA"; and "miRNA" or "microRNA." We identified 3 peer-reviewed manuscripts evaluating miRNA expression in canine UC and compared the reported miRNA expression studies to human UC to identify experimentally validated targets of the dysregulated miRNA. In this review, we highlight the similarities and differences between what is reported in canine UC and human UC and discuss the literature gaps that call for further evaluation.

Objective: The objective of this study was to provide orientation values for fructosamine in adult llamas and to characterize relationships with other laboratory and clinical parameters.

Animals: Data from 22 healthy adult llamas of both sexes.

Methods: A retrospective study was conducted with the findings of a veterinary herd visit from August 2022. Fructosamine measured from plasma samples was characterized, and its relationships with clinical and laboratory diagnostic data was analyzed using descriptive statistics and correlation analysis.

Results: Fructosamine was 311 ± 34 µmol/L (mean ± SD), with a range of 254.8 to 409.2 µmol/L. Males showed significantly higher plasma fructosamine levels than females (P < .05). Plasma fructosamine revealed significant positive correlations with glucose, total protein, and albumin and also with PCV, hemoglobin, calcium, sodium, and selenium. Female llamas revealed further positive correlations with body condition scoring.

Clinical relevance: The results of this study can be used as orientation values for fructosamine in llamas. Fructosamine is used to distinguish acute hyperglycemia caused by stress from chronic hyperglycemia in other species, which might be caused by disorders of the glucose metabolism.

Objective: To investigate the effect of intranasal (IN) flunixin meglumine (FM) and intra-inguinal (IG) lidocaine on castration inflammation using prostaglandin E2 (PGE2) concentration as a biomarker.

Methods: This randomized controlled trial was conducted in March 2022. Blood was collected at -24, 1, and 24 hours postcastration for PGE2 quantification from 195 piglets that received 1 of 8 treatments: (1) saline (1.5 mL) applied IG and IN (0.2 mL) followed by surgical castration (n = 24); (2) saline (1.5 mL) IG and IN (0.2 mL) followed by sham castration (25); (3) lidocaine (20 mg/kg or 1.5 mL) IG followed by surgical castration (24); (4) lidocaine (20 mg/kg or 1.5 mL) IG followed by sham castration (25); (5) FM (2.2 mg/kg) IN followed by surgical castration (25); (6) FM (2.2 mg/kg) IN followed by sham castration (24); (7) lidocaine (20 mg/kg or 1.5 mL) IG and FM (2.2 mg/kg) IN followed by surgical castration (24); and (8) lidocaine (20 mg/kg or 1.5 mL) IG and FM (2.2 mg/kg) IN followed by sham castration (24).

Results: Prostaglandin E2 concentrations did not increase following the castration procedure and were not an effective biomarker of castration inflammation. Piglets that received lidocaine demonstrated no difference in PGE2 levels across all time points. Piglets administered FM had lower PGE2 concentrations at 1 hour and 20 minutes postdrug administration in both the sham and castrated piglets.

Conclusions: Prostaglandin E2 was not an effective biomarker to quantify castration inflammation. Flunixin meglumine was able to reduce PGE2 concentration in piglets regardless of castration procedure, but lidocaine had no impact. Decreased PGE2 levels in FM-treated pigs are likely associated with the drug's ability to mitigate a noncastration-associated inflammatory process occurring independent of the castration procedure.

Clinical relevance: Flunixin meglumine reduced circulating PGE2 concentration in the blood, regardless of the castration procedure, indicating a potential for the drug to mitigate an inflammatory process unrelated to castration.