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in American Journal of Veterinary Research

Abstract

OBJECTIVE

To assess the characteristics of blebs formed after Ahmed glaucoma valve (AGV) surgery in dogs using ultrasound biomicroscopy (UBM) and to analyze their correlation with postoperative intraocular pressure (IOP).

ANIMALS

16 eyes (13 dogs) were diagnosed with primary angle-closure glaucoma and were followed up after AGV surgery from June 2021 to September 2023.

METHODS

In this prospective study, UBM examinations were performed to assess bleb characteristics, including bleb wall thickness and reflectivity. IOP at the time of UBM imaging and the duration from AGV surgery to UBM imaging were recorded. Histological examination of an enucleated eye removed due to uncontrolled IOP leading to blindness was also conducted.

RESULTS

A significant correlation was observed between IOP and relative reflectivity (Pearson r = 0.60; P = .01), and a negative correlation was observed between bleb wall thickness and relative reflectivity (Pearson r = −0.72; P = .002). No significant correlation was observed between the duration from AGV surgery to UBM imaging and either bleb wall thickness or relative reflectivity, respectively. Histological examination of the enucleated eye revealed collagen-rich fibrous encapsulation of the bleb wall, including myofibroblasts that exhibited positive α-smooth muscle actin immunostaining.

CLINICAL RELEVANCE

In dogs that underwent AGV surgery, less dense, thick-walled blebs on UBM tended to maintain IOP within the normal range. However, denser, thinner-walled blebs showed IOP levels above the normal range despite the use of antiglaucoma medications. UBM is a useful tool for evaluating bleb characteristics and their influence on IOP regulation after AGV surgery in dogs.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine if a cytochrome (CYP) P450 enzyme inhibitor can maintain therapeutic plasma levels of voriconazole when administered orally.

ANIMALS

11 healthy, common ravens (Corvus corax).

METHODS

Birds were randomly assigned to pilot study groups to receive voriconazole orally alone or combined with a CYP inhibitor. Pilot studies with 3 CYP inhibitors launched the main study using ciprofloxacin (20 mg/kg) followed 1 hour later by voriconazole (6 mg/kg) every 12 hours for 14 days. Plasma voriconazole concentrations were measured at various time points by HPLC-MS. The study period lasted from September 2016 to December 2020.

RESULTS

The birds failed to maintain therapeutic plasma levels of voriconazole during multidose administration alone or following preadministration with various CYP inhibitors. For the 14-day study period, voriconazole reached a maximum plasma concentration of 2.99 μg/mL with a time-to-peak drug concentration of 1.2 hours following preadministration of ciprofloxacin. One bird was removed from the study due to lethargy, but the other birds completed the study without incident.

CLINICAL RELEVANCE

Ciprofloxacin (20 mg/kg) followed by voriconazole (6 mg/kg) maintained the concentration of voriconazole within the recommended therapeutic range of 0.5 to 5 μg/mL without toxicity. Ciprofloxacin prevented the saturable metabolism of voriconazole and maintained these levels for the study duration. This drug combination could be used in the treatment of chronic aspergillosis in the common raven.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine the efficacy of primary or booster intranasal vaccination of beef steers on clinical protection and pathogen detection following simultaneous challenge with bovine respiratory syncytial virus and bovine herpes virus 1.

METHODS

30 beef steers were randomly allocated to 3 different treatment groups starting at 2 months of age. Group A (n = 10) was administered a single dose of a parenteral modified-live vaccine and was moved to a separate pasture. Groups B (n = 10) and C (10) remained unvaccinated. At 6 months of age, all steers were weaned and transported. Subsequently, groups A and B received a single dose of an intranasal modified-live vaccine vaccine while group C remained unvaccinated. Group C was housed separately until challenge. Two days following vaccination, all steers were challenged with bovine respiratory syncytial virus and bovine herpes virus 1 and housed in a single pen. Clinical and antibody response outcomes and the presence of nasal pathogens were evaluated.

RESULTS

The odds of clinical disease were lower in group A compared with group C on day 7 postchallenge; however, antibody responses and pathogen detection were not significantly different between groups before and following viral challenge. All calves remained negative for Histophilus somni and Mycoplasma bovis; however, significantly greater loads of Mannheimia haemolytica and Pasteurella multocida were detected on day 7 postchallenge compared with day −2 prechallenge.

CLINICAL RELEVANCE

Intranasal booster vaccination of beef steers at 6 months of age reduced clinical disease early after viral challenge. Weaning, transport, and viral infection promoted increased detection rates of M haemolytica and P multocida regardless of vaccination status.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate the prevalence of oral bacteria in the conjunctiva of brachycephalic and nonbrachycephalic dogs.

ANIMALS

12 brachycephalic (9.58 ± 3.55 years) and 12 nonbrachycephalic (8.33 ± 4.92 years) dogs without systemic disease, regardless of breed and sex, were included in the study, and half of the dogs in each group had periodontitis.

METHODS

This prospective study investigated clinical data including craniofacial ratio, ophthalmic examination results, and periodontal status of the included dogs. Bacterial samples were collected by swabbing the oral mucosa and conjunctival surfaces. The presence and quantity of bacteria were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, 16S rRNA sequencing analysis, and the 10-fold dilution method. Statistical analyses were performed to assess correlations and factors influencing the presence of oral bacteria in the conjunctiva.

RESULTS

The most common bacteria in the conjunctival flora in both groups were Micrococcus luteus, Corynebacterium spp, and Staphylococcus spp. The prevalence of oral bacteria on the conjunctival surface was 33%, with a significantly higher incidence in brachycephalic dogs (P = .027). Oral bacteria detected in the conjunctiva were predominantly Frederiksenia canicola, Neisseria spp, and Moraxella spp. Multiple regression analysis identified age, craniofacial ratio, and gingival index as factors influencing the presence of oral bacteria in the conjunctival flora.

CLINICAL RELEVANCE

Oral resident bacteria have often been isolated from severe infectious corneal ulcers. This study provided evidence that brachycephalic dogs may require dental prophylaxis to reduce their oral bacterial load and that the association of oral bacteria in ocular diseases should be considered.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To investigate whether pulse-wave analysis (PWA) performed by trained evaluators facilitates detection of nonsinus rhythm.

ANIMALS

Same-day, high-definition oscillometry pulse-wave data and ECG results of 155 animals (144 dogs and 11 cats) were analyzed.

METHODS

In this cross-sectional study, we enrolled 18 participants from various backgrounds, all of whom received PWA training. The ability to distinguish between sinus and nonsinus rhythms was assessed using receiver operating characteristic curve analysis. The pulse-wave datasets were divided into 5 ECG categories. Agreement between ECG diagnoses and PWA-based arrhythmia detection was evaluated using Cohen κ values, and the correlation between the academic year of veterinary students and their κ values was assessed.

RESULTS

All cardiology researchers demonstrated satisfactory accuracy in distinguishing pathological rhythms using PWA (area under the curve, 0.704 to 0.761), with the highest accuracy in detecting atrial fibrillation (area under the curve, 0.811 to 0.845). Fair agreement with ECG categorization was achieved by all 3 cardiology researchers, 2 of 5 general practitioners, and 3 of 10 veterinary undergraduates. The veterinary undergraduates' years of study were correlated with their diagnostic performance (Spearman ρ = 0.658; P = .019).

CLINICAL RELEVANCE

PWA during routine noninvasive blood pressure measurement showed significant potential for the detection of pathological arrhythmias, notably atrial fibrillation. This approach yielded improved effectiveness when it was used by veterinarians with cardiology experience. Thus, introducing hands-on training courses, particularly those focused on cardiology and interactive workshops, may enable frontline veterinarians to promptly identify arrhythmias using PWA, facilitating timely ECG examinations or referrals.

Open access

Abstract

OBJECTIVE

To investigate inflammatory responses to lipopolysaccharide (LPS) injection in layers.

ANIMALS

33 40-week-old laying hens were used.

METHODS

30 laying hens were divided into 2 groups: the first group was injected with 8 mg/kg LPS, while the second group was injected with sterile saline. At the start of the study, 3 birds served as a baseline and were used as the time 0 controls for both the saline and LPS-treated groups. Blood and spleen tissues were collected at 0 (before) and 1, 2, 3, 4, and 6 hours after injection.

RESULTS

LPS administration increased splenic mRNA levels of IL-1β, IL-2, IL-6, IL-8, IL-10, interferon-γ, and tumor necrosis factor-α (P < .001) and serum IL-6 levels (P < .01) compared to saline injection. The mRNA expression of most cytokine genes increased rapidly toward peak values within 2 hours after the LPS injection, and then the difference between the saline and LPS treatments got smaller as time went on; serum IL-6 reached its highest concentration 2 hours after LPS administration. The magnitude of LPS-induced upregulation of gene expression was the highest for IL-6, followed by IL-1β and IL-8, and tumor necrosis factor-α was the least affected.

CLINICAL RELEVANCE

The temporal and quantitative profile of these inflammatory mediators generated from this study provides valuable information in identifying the optimal time window and appropriate biomarkers for LPS-induced inflammation, which has significant implications in evaluating the effects of interventions on the immune system of chickens.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate and compare the pharmacokinetic parameters of SC ceftazidime administered at 20 and 40 mg/kg to red-eared sliders.

ANIMALS

8 adult red-eared sliders (Trachemys scripta elegans).

METHODS

In a sequential, 2-period study with a 3-week washout period between treatments, ceftazidime was administered SC to turtles at 20 and 40 mg/kg. Blood samples were collected from the subcarapacial sinus at 0, 24, 48, 72, 96, and 120 hours after ceftazidime administration. Plasma ceftazidime concentrations were quantified using reversed-phase HPLC.

RESULTS

Mean plasma half-life after 20- and 40-mg/kg dosing was 39.75 ± 8.0 hours and 33.03 ± 6.56 hours, respectively. Mean maximum plasma concentration after 20- and 40-mg/kg dosing was 71.0 ± 15.93 µg/mL and 120.0 ± 30.62 µg/mL, respectively. Mean plasma ceftazidime concentrations remained ≥ 8 µg/mL, the theoretical MIC for various reptile pathogens for all time points.

CLINICAL RELEVANCE

Results indicate that ceftazidime dosed at either 20 or 40 mg/kg produces plasma concentrations exceeding the theoretical MIC of various reptile pathogens for at least 120 hours. An ideal dosing interval could not be determined, as all plasma concentrations remained above the threshold of interest for all time points. Follow-up studies should focus on establishing a dosing interval and more rigorous monitoring for potential adverse effects.

Open access
in American Journal of Veterinary Research