American journal of veterinary research最新文献

Objective: To describe the pharmacokinetics of the IV formulation of levetiracetam administered intranasally and calculate the absolute bioavailability. Our hypothesis was that levetiracetam would show near complete absorption following a single intranasal dose.

Methods: 8 healthy dogs (4 female, 4 male) from a canine colony were used in a crossover study comparing the pharmacokinetics of intranasal and IV levetiracetam. The study occurred from August through September 2024. A 100-mg dose of levetiracetam was administered via the intranasal and IV routes on separate occasions. Blood was collected from jugular catheters over a 24-hour period following dose administration. Plasma levetiracetam concentrations were analyzed using high-pressure liquid chromatography. Noncompartmental analysis was performed to describe the pharmacokinetics.

Results: Median (minimum to maximum), maximal concentration, time to maximal concentration, and elimination half-life for the intranasal route were 7.85 µg/mL (range, 3.37 to 14.16), 0.98 hours (range, 0.22 to 1.00), and 2.83 hours (range, 2.44 to 3.76), respectively. Median (minimum to maximum) bioavailability was 61% (range, 34% to 85%). The maximal concentration achieved fell within the human reference interval for levetiracetam in 5 of 8 dogs.

Conclusions: Levetiracetam was absorbed to a moderate degree following the intranasal route of administration and appeared to be well tolerated.

Clinical relevance: Levetiracetam is absorbed via the nasal administration route and could be considered a feasible route of administration for at-home rescue protocols. Although concentrations within the human reference interval were achieved in a majority of dogs, a clinical trial is necessary to determine if this method of administration would be effective in a clinical setting.

Objective: To describe the pharmacokinetic parameters of tramadol and its main metabolites, O-desmethyltramadol (M1) and N-desmethyltramadol, and clinically detectable adverse effects after a single orally administered high dose of tramadol in rabbits (Oryctolagus cuniculus).

Methods: 6 experimental and 1 control healthy intact male rabbits of commercial origin were included in February 2025. Following administration of a 30-mg/kg oral dose of tramadol, plasma concentrations of tramadol, M1, and N-desmethyltramadol were determined by UHPLC-MS at 12 predetermined time points. Pharmacokinetic parameters were calculated using commercial software. Fecal production and sedation were evaluated before and after the experiment.

Results: The mean tramadol maximum plasmatic concentration was 91 ± 38 ng/mL, the average time to reach maximum plasmatic concentration was 40 minutes, the terminal half-life was 4.0 ± 2.4 hours, and the mean area under the curve from the first dose to infinity was 192 ± 45 ng/hmL. The M1 metabolite reached concentrations compatible with previously described analgesic effects in rabbits after 10 minutes and for up to 3 hours after administration in some individuals, whereas tramadol did not reach analgesic concentrations. Mild sedation was detected in 4 rabbits at the 20 minute- to 6-hour time points, and fecal production increased from 24 to 48 hours after tramadol administration. No clinically relevant adverse effects were noted.

Conclusions: Administration of 30 mg/kg tramadol, PO, in rabbits results in plasma concentrations of M1 compatible with analgesia.

Clinical relevance: The short duration of action warrants further studies with long-acting formulations of tramadol.

Objective: To describe the incidence, disease distribution, and factors associated with survival to discharge in bearded dragons (BDs) presenting for emergency evaluation.

Methods: There were 242 BDs retrospectively enrolled. Age, sex, weight, presenting complaints, diagnostics, diagnosis, and outcome were summarized with descriptive statistics. Associations between these factors and survival to discharge were evaluated for prognosis.

Results: Frequently presenting complaints were lethargy (109 of 242 [45%]) and anorexia (97 of 242 [40%]). Females more often presented with celomic distension (12 of 100 [12%]) and were diagnosed with reproductive disease (11 of 100 [11%]). Of the BDs evaluated, 140 of 242 (57.9%) BDs survived to discharge, with equal survival between males (72 of 110 [56.9%]) and females (54 of 100 [54%]). Survival was more common when BDs presented with ocular signs (OR, 0.09 [95% CI, 0.01 to 0.69]). Nonsurvival was more common when BDs presented with lethargy (OR, 2.85 [95% CI, 1.68 to 4.83]), anorexia (OR, 2.36 [95% CI, 1.39 to 4.00]), or poor body condition (OR, 3.94 [95% CI, 1.36 to 11.451]) or were diagnosed with celomic effusion (OR, 6.67 [95% CI, 1.85 to 24.07]), anorexia of unknown cause (OR, 2.79 [95% CI, 1.41 to 5.52]), or lethargy of unknown cause (OR, 2.35 [95% CI, 1.19 to 4.63]).

Conclusions: BDs presented with vague clinical signs. Survival was less likely when a diagnosis could not be reached, required extensive testing, or required surgical intervention.

Clinical relevance: Knowledge of presenting complaints, diagnoses, and their prognosis enables veterinarians to provide targeted care for BD emergencies.

Objective: To evaluate the effects of a therapeutic gastrointestinal diet on the apparent digestibility coefficients (ADCs), metabolizable energy (ME), and palatability of the diet, fermentative metabolites, and fecal microbiome of dogs.

Methods: Sixteen 1-year-old healthy Beagles were used. All animals consumed a control diet for healthy adult dogs for 20 days. On day 21, 8 dogs changed to a therapeutic gastrointestinal diet (test diet), and 8 dogs continued receiving the control diet for 35 days. Fresh feces were collected on days 0, 3, 15, and 30 after changing to the test diet for pH, fermentative metabolites, and microbiota analysis. Feces were collected for ADCs and ME analysis of the diets (days 31 through 35). The palatability of the control and test diets was compared at the end of the study.

Results: The test diet presented greater ADCs of nutrients and ME and resulted in lower fecal pH and greater fecal concentrations of ammonia, total biogenic amines, total short-chain fatty acids, and butyrate. β-Diversity analysis revealed distinct fecal microbiome profiles between the diets on days 3, 15, and 30, with a greater abundance of Turicibacter and Faecalibacterium and lower Streptococcus in the test group. Dogs preferred the test to the control diet in the palatability test.

Conclusions: The test diet presented high ADCs of nutrients, high palatability, and beneficially modulated the fecal microbiome and fermentative metabolites of dogs.

Clinical relevance: Providing a highly digestible and palatable diet with functional ingredients may contribute to the treatment of gastrointestinal disorders of dogs.

Objective: To quantify the amount of hilar liver retraction achieved with and without diaphragmotomy in canine cadavers.

Methods: 6 healthy canine cadavers euthanized for reasons unrelated to the study underwent laparotomy in 2023. Fiducial radiopaque markers were placed on the hepatic coronary ligament and diaphragm. Fluoroscopic images were taken at 3 liver manipulation phases: (1) before caudal retraction (CR) (pre-CR), (2) after caudal retraction (post-CR), and (3) after diaphragmotomy (D) with caudal retraction (post-D+CR). Two measurement methods were used to evaluate hepatic caudal displacement. Method 1 used the cranial edge of the closest rib caudal to the liver as a landmark. Method 2 used a fixed point on an esophageal measurement catheter. Linear displacement for both methods at the 3 stages of liver retraction was estimated by linear repeated-measures mixed models. Limits of agreement were estimated by 95% CIs.

Results: Linear caudal displacement was substantially increased post-CR and post-D+CR compared to pre-CR. Compared with pre-CR, the mean linear caudal displacement increased by 2.6 and 3.8 cm for post-CR for methods 1 and 2, respectively. Linear displacement increased by an additional 3.0 cm (method 1) and 3.1 cm (method 2) for post-D+CR. Method 2 measurements consistently exceeded method 1 measurements for both total and relative linear distance.

Conclusions: Diaphragmotomy coupled with manual retraction allows greater caudal retraction of the liver hilus than without diaphragmotomy.

Clinical relevance: This preliminary study shows that the diaphragmotomy procedure may enhance exposure and ease of manipulation and potentially reduce complications associated with limited maneuverability during hilar hepatic surgery.

Objective: To use liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis to quantify kratom alkaloids and metabolites in the urine of healthy dogs following a single oral dose of an encapsulated kratom extract and evaluate the accuracy of an over-the-counter (OTC) human kratom urine test for identifying the presence of kratom alkaloids and metabolites in canine urine.

Methods: Urine samples were collected from 8 healthy female Beagles following a single oral dose of an encapsulated kratom extract (8 mg) every 4 hours for 24 hours. Urine concentrations of kratom alkaloids and metabolites were measured using LC-MS-MS analysis. Urine samples were tested with an OTC human kratom urine test for identification of mitragynine and/or 7-hydroxymitragynine.

Results: In this small cohort of dogs, the OTC human kratom urine test demonstrated 100% sensitivity (6 of 6; 95% CI, 60.97% to 100.00%) and 100% specificity (7 of 7; 95% CI, 64.57% to 100.00%) for identifying kratom alkaloids and/or metabolites. Kratom metabolite 7-hydroxymitragynine had higher urine concentrations compared to the parent alkaloid mitragynine.

Conclusions: Kratom is primarily excreted as metabolites in canine urine following oral administration of a single dose. Although these results are limited by the small sample size and wide CIs, the OTC human kratom urine test reliably detected kratom metabolites in canine urine when compared with LC-MS-MS.

Clinical relevance: The results of this study provide a better understanding of kratom elimination in dogs and support the potential utility of an OTC kratom urine test as a diagnostic tool for suspected kratom exposure; however, larger studies are needed to validate diagnostic performance.

Objective: This study aimed to determine the proportion of cats referred for suspected temporomandibular joint (TMJ) luxation that were confirmed as true cases and to identify their final diagnoses. The objective was to highlight potential differential diagnoses to improve diagnostic accuracy and case management.

Methods: A total of 42 cats that were referred to our hospital for suspected TMJ luxation as a chief complaint from April 2020 to February 2025 were included in the study. According to owner reports, these patients commonly exhibited an inability to close the mouth, apparent mandibular deviation, and, in most cases, signs suggestive of oral pain.

Results: Of the 42 cats studied, only 6 had isolated TMJ luxation. The rest had other diagnoses: 19 with end-stage periodontal disease, 5 with malocclusion, 4 with symphyseal separation, and 3 with open-mouth jaw locking resulting from other causes. Two had mandibular fractures, 2 had no significant findings, and 1 had TMJ ankylosis.

Conclusions: End-stage periodontal disease was the most common diagnosis among cats referred for suspected TMJ luxation. Other final diagnoses included TMJ luxation, malocclusion, fractures, mandibular symphyseal instability, open-mouth jaw locking resulting from other causes, and TMJ ankylosis. Diagnosis is challenging due to nonspecific signs that mimic other oral diseases and are often linked to complex maxillofacial injuries, requiring thorough exams and advanced imaging.

Clinical relevance: This study emphasizes the importance of considering differential diagnoses in cats presenting with signs resembling TMJ luxation and provides references to guide future clinical evaluation and decision-making.

Objective: To retrospectively determine the organization-level intake and outcome changes associated with dog live release rate (LRR) changes in government-related animal shelters.

Methods: Observational statistics (2016 through 2024) provided by shelters to a national database were condensed into baseline and follow-up year pairs. Baseline LRR was binned into low (75% to 90%) and high (90% to 95%). Changes in intake and outcome categories were computed either as fractions of contemporaneous total intakes or outcomes, or as fractions of baseline total outcomes. Field changes were linearly regressed on ΔLRR (change in LRR from baseline to follow-up year), with the year included as a categorical covariate.

Results: In the low-LRR bin, there were 965 (high, 1,082) observations from 360 (high, 435) organizations, with an LRR mean of 84.7% (high, 92.9%) and a ΔLRR SD of 4.1% (high, 2.7%). For low LRR, total outcomes change by 0.50% (high, 0.58%) and intakes by 0.42% (high, 0.24%) per ΔLRR point. Baseline adoptions constitute 36.4% (high, 45.1%) and returns to owner 24.9% (high, 29.3%) of contemporaneous outcomes. Per ΔLRR point, adoption fractions change by 0.49 (high, 0.68) and return-to-owner fractions by 0.06 (high, -0.03). For low LRR, with counts scaled by baseline outcomes, ΔLRR coincides with live outcome changes of 1.46 (high, 1.54) encompassing 0.87 (high, 1.20) community live outcomes, 0.64 (high, 1.07) adoptions, and 0.50 (high, 0.27) outgoing transfers but 0.43 (high, -0.03) net transfers. Intake changes other than transfers are insignificant.

Conclusions: On average, annual LRR increases coincide with increases in adoptions but not reductions in intakes. Changes in outgoing transfers also occur, but partially offset by incoming transfers.

Clinical relevance: The results facilitate benchmarking shelter initiatives and avoiding preconceived assumptions.