Abstract
Tendon injuries are common in both veterinary and human clinical patients and result in morbidity, pain, and lost athletic performance. Consequently, utilizing naturally occurring injuries in veterinary patients as a comparative model could inform the development of novel therapies and increase translation for the treatment of human tendon injuries. Mesenchymal stem cells (MSCs) have shown considerable efficacy for the treatment of experimental and clinical superficial digital flexor tendon injury in the horse; however, the reinjury rate following treatment can remain high and MSC efficacy in treating other tendons is less well known. Additionally, the translation of MSC therapy to human tendon injury has remained poor. Recent evidence indicates that naïve MSC function can be enhanced through exogenous stimulation or manipulation of their environment. This stimulation or activation, herein termed MSC licensing, markedly alters MSC functions associated with immunomodulation, extracellular matrix remodeling, vascular development, bioactive factor production, and endogenous stromal/progenitor cell support. Additionally, a variety of licensing strategies has proven to influence MSC-secreted factors that have positively influenced outcome parameters in both in vitro and in vivo disease models separate from musculoskeletal tissues. Therefore, identifying the optimal licensing strategy for MSCs could ultimately provide an avenue for reliable and repeatable treatment of a broad range of tendon injuries of both veterinary and human clinical patients. This article details current evidence on the effects of licensed MSCs in both in vitro and in vivo disease models of different species and provides commentary on how those effector functions identified may be translated to the treatment of tendon injuries.
Abstract
The fluoroquinolone antimicrobial agents, enrofloxacin and marbofloxacin, were US Food and Drug Administration (FDA) approved in the United States for use in dogs in 1988 and 1999, respectively. There have been many advances since then concerning the pharmacokinetic-pharmacodynamic (PK-PD) evaluation of fluoroquinolones, and there are data available on the susceptibility of targeted pathogens since the original approval. Using this information, the Clinical and Laboratory Standards Institute (CLSI) Veterinary Antimicrobial Susceptibility Testing Subcommittee (VAST) revised its antimicrobial susceptibility testing breakpoints. The previous breakpoints (used in older editions of CLSI standards) for enrofloxacin in dogs were susceptible (S), ≤ 0.5 µg/mL, intermediate (I) 1–2 µg/mL, and resistant (R) ≥ 4 µg/mL. The new breakpoints are S ≤ 0.06 µg/mL for a dose of 5 mg/kg, 0.12 µg/mL for a dose of 10 mg/kg, 0.25 µg/mL for a high dose of 20 mg/kg, and R ≥ 0.5 µg/mL. The breakpoints of 0.12 and 0.25 µg/mL represent a new susceptible-dose dependent (SDD) category. For marbofloxacin, previous breakpoints were S, ≤ 1 µg/mL, I 2 µg/mL, and R ≥ 4 µg/mL. The new breakpoints are S ≤ 0.12 µg/mL for a dose of 2.8 mg/kg, 0.25 µg/mL for a dose of 5.5 mg/kg (SDD), and R ≥ 0.5 µg/mL. The new breakpoints will be published in the next edition of CLSI-Vet01(S) and deviate considerably from the prior breakpoints. Laboratories are encouraged to revise their testing standards. These changes will likely reduce the unnecessary use of these fluoroquinolones in dogs.
Abstract
OBJECTIVE
To describe a nonsurgical endoscopic technique for sex identification in Indonesian blue-tongued skinks (Tiliqua gigas) and to assess accuracy of contrast radiography of the hemipenile/hemiclitoral pouches.
ANIMALS
42 clinically healthy Indonesian blue-tongued skinks between 6 months and 3 years old and weighing between 22 and 550 g.
METHODS
Cystoscopy was performed under general anesthesia. Gonads were visualized through the transparency of the urinary bladder, and their gross morphology was described. Contrast was applied in the tail pouches before obtaining full-body radiographs. Two radiologists, blinded to the sex of the skink, evaluated the radiographs.
RESULTS
Cystoscopy was achieved in all 42 skinks. Visualization of the gonads through the urinary bladder was possible in 41 (98%; 95% CI, 87% to 99%) of the skinks, with 18 of them identified as males and 23 identified as females. Median procedure time was 60 seconds (range, 25 to 180 seconds) and was not associated with procedure order (–0.69; 95% CI, –1.83 to 0.45) or with the weight (0.02 g; 95% CI, –0.07 to 1.0) or the identified sex (11.7; 95% CI, –15.07 to 38.45) of the skink. Radiographs had a sensitivity of 69.6% (95% CI, 47.1% to 86.8%) and a specificity of 75.0% (47.6% to 92.7%) to identify female skinks. All the skinks recovered uneventfully.
CLINICAL RELEVANCE
Cystoscopic sex identification is feasible in Indonesian blue-tongued skinks of various age and size. Considering the difficulty in identifying their sex otherwise, this technique could provide a significant improvement in the veterinary care of this species. In this population, contrast radiographs showed limited accuracy for sex identification.
Abstract
OBJECTIVE
To investigate hemodynamics and morphology of hip joint vasculature in cats with the use of color and pulsed-wave Doppler ultrasonography.
ANIMALS
30 client-owned healthy skeletally immature cats presented for routine examinations between September 7, 2022, and March 25, 2023.
METHODS
Cats between 3.5 to 18 months old with healthy hip joints and Hct within reference ranges (26% to 44.2%) were eligible for inclusion. Color and pulsed-wave Doppler ultrasonography was performed without sedation. Peak systolic velocity (PSV), mean diastolic velocity (MDV), resistance index (RI), and pulsatility index (PI) were measured for major arteries of the hip joints.
RESULTS
Intermediate pulsatility, resistance to flow, and pandiastolic anterograde flow were evident for all arteries evaluated for each joint except for the ligamentum capitis ossis femoris artery (LCOFA). Spectral waveforms for the LCOFA showed a low-resistance pattern with continuous forward diastolic flow. No significant differences were found in the mean PI or MDV between the left and right sides for the ascending branch of the lateral circumflex femoral artery or in the mean PI of the ascending branch of the medial circumflex femoral artery. Mean PSV of the LCOFA was lower (but nonsignificantly) for left hip joints vs right hip joints, whereas other values were often higher on cats’ left side vs their right.
CLINICAL RELEVANCE
This study provided insight into the morphology and hemodynamics of the femoral head vasculature in skeletally immature cats and showed Doppler ultrasound values to study the clinically normal blood supply to hip joints in cats.
Abstract
OBJECTIVE
To verify the validity of finite element analysis (FEA) predictions obtained from a canine lumbar segment model in comparison with experimental biomechanical testing results from the same subjects.
ANIMALS
6 healthy beagle dogs were euthanized for other purposes.
METHODS
The L1–2 and L5–6 segments were harvested from euthanized animals and subjected to rotation tests and compression tests, respectively, using both ex vivo mechanical testing and FEA. For each method, we recorded the maximum torque value and angle of vertebral body rotation at rupture observed in rotation tests, as well as the maximum stress value and displacement of the vertebral body endplate at rupture measured from compression tests. We then calculated Pearson’s correlation coefficient to determine correlations between the angle of gyration and displacement at rupture determined by mechanical testing and FEA. The study started on March 26, 2021, and ended on March 18, 2023.
RESULTS
For the rotation test, correlation coefficients for the maximum torque and rotation angle of the vertebral body at rupture were r = 0.92 and 0.96, respectively. For the compression test, correlation coefficients for the maximum stress and displacement of the vertebral body endplate at rupture were r = 0.73 and 0.94, respectively. All results showed strong correlations between the FEA predictions and ex vivo mechanical test results.
CLINICAL RELEVANCE
These findings suggest that FEA predictions are sufficiently reliable for ex vivo mechanical test results for biomechanical studies of canine lumbar segment models.
Abstract
OBJECTIVE
To elucidate the cardiovascular effects of escalating doses of phenylephrine and norepinephrine in dogs receiving acepromazine and isoflurane.
ANIMALS
8 beagles aged 1 to 2 years (7.4 to 11.2 kg).
METHODS
All dogs received acepromazine 0.01 mg/kg, propofol 4 to 5 mg/kg, and isoflurane and were mechanically ventilated. Mean arterial pressure (MAP) from a femoral artery catheter and continuous electrocardiogram were recorded. Cardiac output (CO) was measured with transpulmonary thermodilution. Systemic vascular resistance (SVR), global end-diastolic volume (GEDV), and global ejection fraction (GEF) were subsequently calculated. Phenylephrine and norepinephrine were infused in random order at 0.07, 0.3, 0.7, and 1.0 μg/kg/min. All variables were measured after 15 minutes of each infusion rate. The effects of dose, agent, and their interaction on the change of each variable were evaluated with mixed-effect models. A P < .05 was used for significance.
RESULTS
Atrial premature complexes occurred in 3 dogs during norepinephrine infusion at doses of 0.3, 0.7, and 1 μg/kg/min; no dysrhythmias were seen with phenylephrine administration. MAP increased during dose escalation (P < .0001) within each agent and did not differ between agents (P = .6). The decrease in HR was greater for phenylephrine (P < .0001). Phenylephrine decreased CO and GEF and increased GEDV and SVR (all P < .03). Norepinephrine decreased the SVR and increased CO, GEDV, and GEF (all P < .03).
CLINICAL RELEVANCE
Our results confirm that phenylephrine increases arterial pressures mainly through vasoconstriction in acepromazine-premedicated dogs while norepinephrine, historically considered a vasopressor, does so primarily through an increase in inotropism.
Abstract
OBJECTIVE
To compare plasma glucagon-like peptide-2 (GLP-2) concentrations in dogs with treatment-naïve chronic enteropathies to healthy dogs and describe changes over time in dogs with chronic enteropathies (CE).
ANIMALS
18 client-owned dogs with treatment-naïve CE and 17 client-owned healthy control dogs.
METHODS
This was a prospective study. Fasting, 1-hour, and 3-hour postprandial plasma GLP-2 concentrations were measured using a commercial immunoassay in healthy dogs and dogs with uncontrolled, untreated CE. Repeated fasting and postprandial plasma concentrations were measured in dogs with CE after initiating directed treatment for gastrointestinal disease.
RESULTS
There was no significant difference between fasting and postprandial GLP-2 concentrations in either group. Dogs with treatment-naïve CE had lower fasting (mean, 424 ± SD 176 pg/mL) plasma GLP-2 concentrations than healthy dogs (1184 ± 435 pg/mL; P < .0001). Fasted plasma GLP-2 concentrations (624 ± 314 pg/mL) remained lower in dogs with CE than in healthy dogs at recheck.
CLINICAL RELEVANCE
Dogs with CE have disrupted GLP-2 secretion. Future studies are required to evaluate subsets of CE and changes in response to therapy.
Abstract
OBJECTIVE
To identify prognostic indicators and inflammatory markers associated with nonsurvival in dogs with gallbladder mucoceles (GBMs) following cholecystectomy and to evaluate C-reactive protein (CRP) and haptoglobin concentrations in dogs with GBMs compared to healthy controls.
ANIMALS
25 dogs that underwent cholecystectomy for removal of GBM and 20 healthy control dogs.
METHODS
A prospective, multicenter cohort study. Survival outcomes to hospital discharge and 2 weeks postdischarge were recorded from medical records. Laboratory variables, inflammatory markers (CRP and haptoglobin), and 25-hydroxyvitamin(OH) D (25[OH]D) concentrations were measured preoperatively. Associations between signalment, clinicopathologic variables, acute patient physiologic and laboratory evaluation (APPLEFAST) scores, inflammatory markers, 25(OH)D concentration, and survival were analyzed using logistic regression.
RESULTS
76% (19/25) and 68% (17/25) of dogs survived to hospital discharge and 2 weeks postdischarge, respectively. For each additional year of age, the odds of nonsurvival in hospital and 2 weeks postdischarge increased by 2.2 (P = .01; 95% CI, 1.2 to 5.0) and 1.7 (P = .04; 95% CI, 1.0 to 3.2), respectively. Intraoperative systolic blood pressure ≤ 65 mm Hg increased the probability of nonsurvival in hospital (P < .04). Gallbladder perforation, APPLEFAST scores, and preoperative serum concentrations of CRP, haptoglobin, and 25(OH)D were not associated with survival. Serum CRP and haptoglobin concentrations were greater in dogs with GBM compared to controls (P < .001).
CLINICAL RELEVANCE
Increasing age and intraoperative systolic blood pressure ≤ 65 mm Hg were associated with nonsurvival in dogs with GBM undergoing cholecystectomy. Serum CRP, haptoglobin, and 25(OH)D were not associated with nonsurvival postcholecystectomy in this sample population.
Abstract
OBJECTIVE
To determine prognostic relevance of various patient factors and intraoperative variables associated with surgical management of small intestinal obstruction in pet rabbits.
ANIMALS
114 pet rabbits with 141 presentations of small intestinal obstruction treated surgically between June 2011 and December 2021.
METHODS
In a retrospective observational study design, medical records were reviewed for rabbits with small intestinal obstruction that had undergone surgical intervention. Data were collected on variables of interest and outcome (survival to hospital discharge). Univariable and multivariable logistic regression analyses were performed to identify variables associated with survival.
RESULTS
Overall survival was 75.2% (106/141). Specifically, 95.7% (22/23) of presentations involving rabbits < 25 months survived. The odds of survival on univariable modeling were significantly lower in presentations of rabbits > 72 months compared with those < 25 months (OR, 0.05; 95% CI, 0.01 to 0.40; P = .005). Rectal temperature, clinicopathologic findings, etiology of obstruction, presence of full-thickness gastrointestinal wall injury, and previous small intestinal obstruction surgery did not show significant effects on survival. In a multivariable model that controlled for plasma potassium and calculated plasma osmolarity and tonicity, the odds of survival in presentations of rabbits > 72 months were 95% lower than those < 25 months (OR, 0.05; 95% CI, 0.01 to 0.50; P = .012).
CLINICAL RELEVANCE
Surgical intervention should be considered a suitable treatment option for small intestinal obstruction in rabbits < 72 months and carried a good prognosis. The most common etiology was consistent with a compressed hair pellet, and extraluminal digital manipulation into the cecum was a successful surgical technique in most presentations.
