American journal of veterinary research最新文献

Objective: To visualize the endothelial glycocalyx in equine intestinal vessels using electron microscopy and immunohistochemistry and to evaluate the impact of induced endotoxemia on its integrity.

Methods: 6 healthy horses free of gastrointestinal disease were anesthetized with dexmedetomidine, ketamine, and diazepam and mechanically ventilated under isoflurane anesthesia. Jejunal venous tissue samples were collected after perfusion fixation with lanthanum nitrate before and 120 minutes after endotoxemia induced by IV administration of 30 ng·kg-1 Escherichia coli lipopolysaccharide. For transmission electron microscopy, samples were fixed in lanthanum nitrate solution and embedded in epoxide resin. Additional samples were fixed in formaldehyde, embedded in paraffin, and sectioned for indirect immunohistochemistry to assess heparan sulfate, syndecan-1, catalase, and superoxide dismutase-2 expression.

Results: The endothelial glycocalyx ultrastructure was successfully visualized in 3 of 6 horses. Morphological variations, particularly in glycocalyx thickness (up to 2.5 µm), were observed. Endotoxemia-related alterations indicating structural disruptions were evident in these horses. Immunohistochemical staining for syndecan-1 and superoxide dismutase-2 showed no assessable immunoreactivity, whereas heparan sulfate and catalase immunolabelling were detected on the endothelium.

Conclusions: The endothelial glycocalyx of intestinal vessels was visualized for the first time in horses. Among the tested antibodies, only those against heparan sulfate and catalase demonstrated endothelial reactivity, confirming their presence as components of the equine glycocalyx. Lipopolysaccharides may cause structural disintegrity and loss of glycocalyx.

Clinical relevance: Visualization of the equine endothelial glycocalyx enhances understanding of vascular pathophysiology in endotoxemic horses. Investigation of the glycocalyx remains technically demanding.

Objective: To identify optimal cadaveric preparation methods for sentinel lymph node mapping in experimental procedures.

Methods: Apparently healthy canine cadavers were obtained from local shelters following humane euthanasia unrelated to the study. This experimental study was conducted from October 2023 through July 2024 at the University of Florida College of Veterinary Medicine. Cadaveric preparations were categorized as follows: fresh, refrigerated, frozen-thawed, and heated (refrigerated and frozen specimens). Indocyanine green (ICG) was injected into established lymphosomes, targeting the superficial cervical, axillary, superficial inguinal, and popliteal lymph nodes. Lymphatic tracts were identified using near-infrared fluorescence. Time to lymph node uptake or cessation of tract progression and tract distance (centimeters) was recorded to calculate velocity (cm/s) when applicable. Lymph nodes were then extirpated to assess fluorescence.

Results: 9 adult mixed-breed canine cadavers were used, with a lymph node distribution of 11 fresh, 30 refrigerated, 3 refrigerated-heated, 17 frozen-thawed, and 3 frozen-thawed-heated specimens. Fresh and refrigerated cadavers demonstrated consistent and reliable uptake of ICG into the lymphatic tracts and the respective lymph nodes. Frozen-thawed cadavers demonstrated consistent lymphatic tract uptake but inconsistent uptake to the respective lymph nodes. Heating did not improve lymph node fluorescence in refrigerated or frozen-thawed cadavers.

Conclusions: Fresh and refrigerated cadaveric preparations are ideal for sentinel lymph node mapping with ICG. Heating of the cadavers did not improve lymph node fluorescence.

Clinical relevance: When fresh canine cadavers are not accessible, refrigerated cadavers can be reliably used for experimental peripheral sentinel lymph node mapping.

Objective: To characterize age-related trajectories of the relative concentrations of anti-virulence-associated protein A (VapA) immunoglobulin (Ig)-G1, IgG3/5, IgG4/7, and IgA in serum and bronchoalveolar lavage fluid (BALF) as indicators of systemic and intrapulmonary immune responses in foals naturally exposed to Rhodococcus equi.

Methods: Blood and BALF samples were collected at ages 4, 14, 28, and 56 days from healthy Quarter Horse foals (n = 19) naturally exposed to R equi. Samples were tested via ELISA for relative concentration of IgG1, IgG3/5, IgG4/7, and IgA recognizing the VapA of R equi. Data were analyzed using linear mixed-effects modeling to compare VapA ELISA results by age for IgG subisotypes and IgA.

Results: Serum relative concentrations of VapA-specific IgG1, IgG3/5, IgG4/7, and IgA of 19 foals did not differ significantly during the first 28 days of age but increased nearly 10-fold by age 56 days. Similarly, BALF relative concentrations of VapA-specific IgG1, IgG3/5, and IgG4/7 in these foals did not differ significantly during the first 28 days of age but increased by about 10-fold by age 56 days. In contrast, BALF relative concentrations of VapA-specific IgA increased progressively with age.

Conclusions: Natural exposure results in progressive increase in BALF concentration of IgA but not IgGs, indicating intrapulmonary IgA response to virulent R equi.

Clinical relevance: Foals do not mount strong antibody responses to R equi when they are most vulnerable to infection. Further investigation is warranted to determine if increasing intrapulmonary antirhodococcal IgA is a correlate of protective immunity or merely a marker of exposure.

Objective: To evaluate the dose-dependent effects of single dosing of dapagliflozin on pharmacodynamics, diuresis, and ketogenesis in dogs.

Methods: This study included 5 healthy Beagles. A single dose of dapagliflozin (0.1, 0.3, or 1.0 mg/kg) or placebo was orally administered (randomized 14-day intervals) to each dog. Blood and urine samples were collected prior to administration and at 1, 2, 3, 4, 5, 6, 9, 12, and 24 hours after administration. A urinary catheter was placed from 0 to 6 hours after administration to monitor urine volume and collect samples; thereafter, urine was collected using a metabolic cage. Plasma ketone bodies, sodium, potassium, chloride, and glucose concentrations were measured. Urinary sodium, potassium, chloride, glucose, and urine volume were measured and compared among the treatment groups.

Results: 24-hour urinary glucose excretion was significantly increased in the 0.3-mg/kg group compared with the 0.1-mg/kg group. However, no significant difference in 24-hour urinary glucose excretion was observed between the 0.3-and 1.0-mg/kg groups. Plasma ketone body concentration was significantly higher in the 1.0-mg/kg group compared with the placebo group at 4, 5, 6, 12, and 24 hours after administration. The 6-hour urine volume (mL/kg) was significantly higher in the 1.0-mg/kg group compared with the placebo group.

Conclusions: In healthy dogs, a single oral administration of dapagliflozin at 1.0 mg/kg induced both ketogenic and diuretic effects.

Clinical relevance: This study provides preliminary insight into dapagliflozin's effects in healthy dogs; further studies are needed to assess relevance in dogs with heart failure.

Objective: To determine the efficacy of iodine disinfection and effect of storage on tilapia skin wound dressing via microbiological, histological, and spectroscopic assessment.

Methods: Farm-raised, fresh tilapias were included in this prospective ex vivo study conducted in September of 2024. Tilapia fish skin (TFS) was harvested and treated with 10% iodine or saline for 15 minutes. Each group was aseptically packaged, stored (4 °C), and evaluated on days 0, 1, 3, and 7. Colony-forming units were counted from bacterial cultures. Structural integrity was determined histologically by collagen integrity (grade 0 to 3), organization (grade 0 to 3), and intensity (percentage). Lipid concentration was analyzed via gas chromatography-mass spectrometry of extracted fish oil.

Results: 9 tilapias (n = 9) were enrolled. Mean bacterial counts following iodine and saline treatment were 0.56 ± 0.88 CFUs/mL and 19.67 ± 6.12 CFUs/mL, respectively. Iodine-treated TFS maintained disinfection after 7 days of storage (mean bacterial count, 4.11 ± 3.48 CFUs/mL). Mean collagen integrity grades following iodine treatment and 7 days of storage were 1.83 ± 0.41 and 1.33 ± 0.52, respectively. Mean collagen organization grades following iodine treatment and 7 days of storage were 1.83 ± 0.41 and 2 ± 0, respectively. Iodine-treated TFS collagen intensity was low throughout the study duration (range, 15.61% to 26.59%). Lipids were variably detectable in all samples. No eicosapentaenoic or docosahexaenoic acid was detected in any samples.

Conclusions: Iodine-disinfected, cold-stored TFS maintained disinfection and structural integrity for 7 days.

Clinical relevance: TFS can be readily harvested, disinfected, and stored. Future studies are needed for lipid profiling.

Objective: To determine whether low-level laser therapy (LLLT), alone or with chlorhexidine (CLX; CLX + LLLT), improves clinical indices of gingival inflammation, gingival temperature, and systemic cytokines compared with CLX alone in cats with early-stage periodontal disease (American Veterinary Dental College stage 1 to 2).

Methods: Cats diagnosed with American Veterinary Dental College stage 1 to 2 periodontal disease were randomized to 3 groups (CLX, LLLT, and CLX + LLLT; n = 7/group) after full-mouth scaling. Treatments were CLX spray, intraoral 905-nm gallium arsenide LLLT, or both for 7 days. Primary outcomes included probing pocket depth, gingival index, plaque index, and gingival surface temperature. Plasma tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 were secondary outcomes. Thermography and blood sampling were also performed on days 0 and 8.

Results: Mean probing pocket depth decreased by 0.27 mm in CLX, 1.24 mm in LLLT, and 1.20 mm in CLX + LLLT. Gingival index and plaque index declined in all groups, with larger reductions in LLLT-treated cats. Gingival temperature decreased in LLLT (-3.1 °C) and CLX + LLLT (-4.3 °C). Tumor necrosis factor-α decreased in CLX + LLLT (-7.4 ng/L). Interleukin-6 decreased only in CLX + LLLT, and IL-1β changes were negligible.

Conclusions: LLLT, particularly with CLX, produced greater improvements in gingival inflammatory indices, gingival temperature, and inflammatory markers than CLX alone.

Clinical relevance: LLLT appears to be a safe and effective adjunct for the short-term management of gingival inflammation in cats with early-stage periodontal disease following professional dental cleaning.

Objective: To determine whether a single oral dose of gabapentin would generate any changes in heart rate or respiratory rate or behaviors during and after handling of adult domestic pigeons (Columba livia domestica).

Methods: Pigeons were housed alone on the day of the study but were otherwise group housed throughout the 9-day study period. Pigeons were assessed before handling and at 1 and 2 hours posttreatment. Behaviors (resting, aggressive, reactionary, maintenance, and feeding behaviors) and physiologic parameters were evaluated before, during, and after handling at each time point. A modified human intruder test, sedation score, and resistance score were developed and compared between time points.

Results: As part of a blinded, randomized, crossover study, 20 pigeons received 50 mg/kg of oral gabapentin or an equal volume of tap water (control) with an 8-day washout period. Respiratory rates were significantly higher in the control group at 2 hours during the intruder test and at 1 and 2 hours posttreatment in the period following the exam. Resistance scores were significantly higher in the control group at 2 hours posttreatment during handling. There was no significant difference in heart rates or behaviors. Four pigeons exhibited mild sedation after gabapentin administration. No major adverse effects were observed.

Conclusions: Gabapentin administered orally at 50 mg/kg to pigeons decreased respiratory rates and resistance scores during and after examinations for up to 2 hours. Mild sedation was the only adverse effect observed.

Clinical relevance: Oral gabapentin may be beneficial when handling pigeons and may reduce stress associated with handling.

Objective: To evaluate the thermal antinociceptive effects of methadone after IM administration to orange-winged Amazon parrots (Amazona amazonica).

Methods: 8 Amazon parrots received IM methadone hydrochloride (1, 3, and 6 mg/kg) and saline (0.9% NaCl) solution in a masked randomized, within-subjects, balanced complete crossover experimental design. The thermal foot withdrawal threshold (TFWT) was determined 5 minutes before (baseline) and 0.5, 1.5, 3, and 6 hours after treatment administration. Agitation-sedation scores and other adverse effects were evaluated in the test box at each time point before each TFWT.

Results: Methadone at 6 mg/kg significantly increased TFWT when compared with control by an average of 1.9 ± 0.5 °C accounting for baseline values. Methadone also caused agitation for 1, 3, and 6 mg/kg at 0.5 to 1.5 hours compared to control and increased nausea-like behavior (opening the beak and moving the tongue back and forth) for all doses up to 3 hours posttreatment compared to control. Although ataxia was not significant overall, some birds showed ataxia at 0.5 and 1.5 hours following administration of 6 mg/kg.

Conclusions: Methadone administered IM to orange-winged Amazon parrots at 6 mg/kg significantly increased TFWT and appears to have a rapid onset and relatively short duration. Agitation and nausea-like behavior were also observed at lower doses.

Clinical relevance: The benefit of rapid onset, potent analgesic effect, and added mechanisms of action to the opioid-mediated analgesia make methadone an added choice for clinical use in this species. However, these doses caused neuroexcitation with agitation and nausea-like behavior, which should be considered in clinical use.

Objective: To determine the diagnostic yield of abdominal ultrasound and thoracic radiographs in an otherwise systemically healthy population of dogs undergoing tibial plateau leveling osteotomy.

Methods: Medical records from 2 private-practice institutions were retrospectively reviewed to identify otherwise systemically healthy dogs undergoing an elective tibial plateau leveling osteotomy that were offered preoperative 3-view thoracic radiographs and/or abdominal ultrasound from June 1, 2019, through June 30, 2022. Multivariate statistical analysis was performed to compare the odds of diagnosing a new comorbidity and to analyze all patients that were offered preoperative imaging.

Results: A total of 258 client-owned dogs of various breeds were recorded between both hospitals. In total, 116 of 258 dogs (45.0%) solely received thoracic radiographs, 10 of 258 (3.9%) solely received abdominal ultrasound, and both were performed in 61 of 258 (23.6%). Eighty-seven of 258 dogs (33.7%) had either thoracic radiographs, abdominal ultrasound, or both performed preoperatively.

Conclusions: New comorbidities were diagnosed in 13.8% of patients with thoracic radiographs and in 70% of patients with abdominal ultrasound. Patients over the age of 12 years were more likely to have a new comorbidity diagnosed.

Clinical relevance: Abdominal ultrasound is 163 times more likely to lead to diagnosis of a new comorbidity when compared to thoracic radiographs, and the incidence of a new diagnosis was more likely in dogs over the age of 12.