Veterinary journal最新文献

Endometrial health is vital for the reproductive efficiency of broodmares and accurate diagnostic testing is crucial for directing the best treatment options and outcomes. Confocal laser endomicroscopy (CLE) is an endoscopic technique for obtaining in-vivo, real-time microscopic imaging of tissues using a fiber optic probe. CLE relies on induced tissue fluorescence and fluorescein sodium, given intravenously, is the contrast agent most used in human medicine. This study aimed to determine the feasibility of CLE for imaging equine endometrium and determine a standard dose of fluorescein sodium to achieve optimal cellular imaging. In-vivo CLE was performed on 44 mares, and the images were compared with routine histopathological analysis of endometrial biopsies. No adverse reactions occurred after IV fluorescein sodium administration and a dose of 4 mg/kg was established (0.04 mL/kg of 10 % fluorescein sodium solution) to achieve optimal image contrast. CLE enabled multiple regions of the endometrium to be assessed quickly. Distinct tissue architecture patterns could be appreciated using CLE, and the luminal epithelium could be assessed for integrity (ulceration) and exocytosed inflammatory cells. Endometrial gland distribution, density, shape, and epithelial height were evaluated. Blood vessels were clearly outlined, and inflammatory cells and fibrosis were discernable within the interstitium. Image quality varied between mares, and the stage of oestrous cycle may have been a factor of influence. This novel imaging modality enables collection of “virtual” biopsies and facilitates critical assessment of multiple regions of the uterus compared with the standard histopathologic assessment of a single random tissue biopsy.

Transcriptome analysis was performed on the thymus of Japanese Black calves that were necropsied due to poor prognosis, to characterize changes associated with acute thymic involution. Gene expression profiles obtained by DNA microarray analysis of eight calf thymuses were classified into three patterns that correlated with the histopathological stage of acute thymic involution. Using principal component analysis, the first principal component of the global gene expression levels in the calf thymus was associated with the stage of acute thymic involution, suggesting that histopathological changes greatly influence the gene expression profile. Gene ontology enrichment analysis revealed that genes related to cell proliferation, wound healing, and inflammatory responses were the main contributors to the first principal component. Real-time RT-PCR showed that the thymus had lower expression of PCNA, KIFC1, and HES6, and higher expression of SYNPO2, PDGFRB, and TWIST1 during acute thymic involution. Immunohistochemistry demonstrated a decrease in the rate of Ki67-positive cells in the thymic cortex during the late stage of acute thymic involution. The rate of cleaved caspase-1-positive cells increased in the thymic cortex at an earlier stage than the increase in the rate of cleaved caspase-3-positive cells. Vimentin, which was almost absent in the non-involuted thymic cortex, appeared in the thymic cortex during acute thymic involution. These results suggest that in farmed calves with a poor prognosis, inflammatory responses and impaired thymocyte proliferation are primarily involved in acute thymic involution.

A prospective, randomized, blinded experiment was conducted to compare the effects of intranasal (IN) dexmedetomidine (Dex, 10 µg/kg; n=12) alone or combined with midazolam (DexM, 0.3 mg/kg; n=12) or ketamine (DexK, 2 mg/kg; n=12) in healthy dogs. Ease of administration (EA1), total administration time (TAT), time for first (TA1) and second nostril administration (TA2), and adverse events during atomization were recorded. Two days later, EA2 was assessed by IN atomization of injectable water as an additional outcome variable. Onset of sedation was evaluated, along with behavioral scores and physiological parameters from T0 (baseline) to T120. Statistical analyses included Chi-square, one-way ANOVA or Kruskal-Wallis, repeated measures or Friedman’s ANOVA, and Wilcoxon’s tests. Significance was p≤0.05.

Onset of sedation was 12.9 ± 4.1, 18.2 ± 7.5, and 9.9 ± 4.3 mins (mean ± SD) for Dex, DexM, and DexK, respectively. Onset was shorter in DexK compared to DexM (p=0.002), explaining the lower behavioral scores in DexM at T15. All dogs in Dex and DexK reached adequate sedation, with peak sedation occurring at T30, while some dogs in DexM never reached adequate sedation and this group peaked at T45. Adverse events such as saliva drooling and pawing at the nose were significantly higher in DexM and DexK, explaining their differences in TA2, TAT, and EA1 comparing to Dex. EA2 was also higher in Dex compared to DexM and DexK. In conclusion, Dex was better tolerated in dogs and DexK showed faster and more profound sedative effects. Due to paradoxical excitement, unpredictable sedation, and nasal irritation, DexM is not recommended.

The use of grimace scales enables the clinical identification of changes in the facial expressions of animals caused by pain. The Horse Grimace Scale (HGS) is one such tool, comprising a pain coding system based on facial expressions and assessing six Facial Action Units (FAUs). Each FAU is accompanied by descriptions and anatomical details to assist the evaluator. However, the morphological descriptions for certain FAUs in the HGS are not sufficiently detailed, potentially hindering accurate interpretation. This study is an analytical investigation aimed at enhancing the morphoanatomical details in the HGS and providing raters with more comprehensive materials for pain evaluation in horses using this scale.

To achieve this, detailed anatomical analyses were conducted using established references in veterinary anatomy. Initially, we propose substituting the term 'ear' with 'auricle' or 'pinna' and replacing 'area above the eye' with 'supraorbital region' for anatomical accuracy. Additionally, we introduce detailed morphoanatomical descriptions that identify specific landmarks, with the goal of ensuring more consistent application of the HGS and reducing interpretation variability. Furthermore, this study provides an explanation of the muscles involved in the investigated FAUs. These adjustments on the descriptions and evaluations remain unverified, however it is anticipated that the descriptive enhancements lead us to understand that higher interobserver reliability can be achieved for each of the FAUs.

Hemorrhagic shock and subsequent resuscitation can cause significant dysregulation of critical systems, including the vascular endothelium. Following hemorrhage, the endothelial lining (glycocalyx) can shed, causing release of glycocalyx components, endothelial activation, and systemic inflammation. A canine model of hemorrhagic shock was used to evaluate five resuscitation fluids, including Lactated Ringers+Hetastarch, Whole Blood (WB), Fresh Frozen Plasma+packed Red Blood Cells (FFP+pRBC), and two hemoglobin-based oxygen carrier (HBOC) fluids, for their impact on glycocalyx shedding. Under anesthesia, purpose-bred adult canines were instrumented and subjected to a controlled hemorrhage with blood being drawn until a mean arterial pressure of <50 mmHg was reached or 40 % of the estimated blood volume was removed. Canines were left in shock for 45 mins before being resuscitated with one of the resuscitation fluids over 30 mins. Following resuscitation, the dogs were monitored up to 2 weeks. Following an additional 3–4 weeks for washout, the canines repeated the protocol, undergoing each resuscitation fluid individually. Blood samples were collected during each round at various timepoints for serum isolation, which was used for detection of glycocalyx biomarker. Comparison of baseline and post-hemorrhage alone showed a significant reduction in serum protein (p<0.0001), heparan sulfate (p<0.001), and syndecan-1 (p<0.0001) concentrations, and a significant increase in hyaluronan (p<0.0001) concentration. Intercomparisons of resuscitation fluids indicated minimal differences in glycocalyx markers over time. Comparisons within each fluid showed dynamic responses in glycocalyx biomarkers over time. Relative to individual baselines, syndecan-1 was significantly reduced after resuscitation in most cases (p<0.0001), excluding WB and FFP+pRBC. In all cases, VE-cadherin was significantly elevated at 24 hr compared to baseline (p<0.001). Hyaluronan was significantly elevated by 3 hr in all cases (p<0.01), except for HBOC fluids. Total glycosaminoglycans were significantly reduced only at 3 hr (p<0.001) for non-HBOC fluids. Similarly, heparan sulfate was significantly reduced with all fluids between resuscitation and 24 hr (p<0.01), except WB. The temporal changes in canine glycocalyx biomarkers were atypical of hemorrhage response in other species. This suggests that the hemorrhage lacked severity and/or typical glycocalyx biomarkers do not reflect the canine endothelium compared to other species. Further research is needed to characterize the canine endothelium and the response to resuscitation fluids.

Management of diarrhoea in horses is usually non-specific and supportive. Faecal microbiota transplantations (FMT) are used to manage dysbiosis in horses with diarrhoea. There are few studies investigating the effects of storage on prepared FMT solutions. This study was an in vitro non-randomised controlled experiment that investigated the effects of FMT solution preparation and storage on the faecal microbiota. Fresh faeces were collected from five healthy adult horses and used for DNA extraction and preparation of FMT. From each FMT, seven aliquots were collected and DNA was extracted immediately after FMT preparation (0 hr), after storage at 4 °C for 24, 48 or 72 hours, and after storage at −20°C for 7 days, 14 days or 28 days. The extracted DNA was used for 16 S rRNA gene sequencing.

The relative abundance, alpha diversity and beta diversity between fresh faeces and FMT 0 hr showed no differences (P ≥ 0.05). There were minimal changes in the microbiota of FMT stored at 4°C for up to 72 hours and −20°C for up to 28 days. The results of this study indicate that preparation of equine FMT solution has minimal effect on the microbiota in comparison to fresh faeces. FMT solution can be stored at 4°C for up to 3 days and −20°C for 28 days without major change in microbiota.

This study investigates the pharmacokinetics (PK) of montelukast (MTK), a cysteinyl leukotriene receptor antagonist increasingly being considered in veterinary medicine. In dogs, MTK has found indications mainly for treating atopic dermatitis as an off-label use. Six male Labrador dogs underwent a single oral administration of MTK (40 mg/dog) in both fasted and fed conditions according to an open, single-dose, two-treatment, two-phase, cross-over design, with a washout period of one week. Blood was withdrawn to heparinized tubes at 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 10, and 24 hr. MTK plasma concentrations were quantified using a validated HPLC method, and the data were analysed using PKanalix™ software with a non-compartmental approach.

Concentrations remained quantifiable at 24 hr after administration, under both conditions. No significant differences were observed in the PK parameters between the fasted and fed states. MTK was relatively eliminated slowly, with t1/2 values of 8.10 and 7.68 hr after fasted and fed states, respectively. The attainment of maximum concentration (C_max) occurred at a T_max of 4 hr, with mean values of 1.98 μg/mL and 2.80 μg/mL under fasted and fed conditions, respectively. Given the unknown therapeutic range of MTK in dogs and the absence of controlled studies proving its efficacy in this species, further dosing adjustments and refinements should be considered based on both the current PK data and the need to establish an effective therapeutic range, if present. Future research should focus on efficacy studies, multiple-dose investigations, and pharmacodynamic assessments to evaluate the suitability of MTK use in dogs.

Macrocyclic lactone (ML) anthelmintics are currently the only class of drugs available for canine heartworm prevention. Recent reports of Dirofilaria immitis infection occurring in dogs reportedly receiving ‘rigorous’ prevention in Queensland, Australia, coupled with the confirmation of ML-resistant isolates in the USA, has led to speculation about the potential emergence of ML-resistance in Australia. In this study, we describe two cases (Dog 1 and 2) of asymptomatic canine heartworm disease in Townsville, Australia, that were reportedly receiving ‘rigorous’ heartworm prevention according to the owners’ claims. We aimed to deploy currently available tools to assess the phenotypic and genotypic ML-resistance status of these two dogs. For phenotypic testing, we performed an in-vivo 7-day microfilariae suppression test using a dose of spot-on moxidectin (Advocate™ for Dogs, 100 g/L imidacloprid + 25 g/L moxidectin). This formulation is marketed as Advantage Multi® for Dogs in the USA, which claims a D. immitis microfilaricidal effect. For genetic testing, an Illumina amplicon metabarcoding approach was used to target single nucleotide polymorphisms (SNPs) previously associated with ML-resistance in D. immitis from the USA. Dog 1 and Dog 2 demonstrated <10 % and <40 % reductions in circulating microfilariae seven days after moxidectin treatment, respectively. These phenotypes were not corroborated by genetic SNP testing, as both dogs were classified as susceptible across all examined markers. To streamline testing of D. immitis SNPs, we developed a rhAmp™ SNP qPCR approach for rapidly genotyping suspect cases of ML-resistant infections at the two major loci (L15709_A and L30575). These findings illustrate a phenomenon shown in some heartworm cases outside the USA, whereby infected dogs are failing to see marked reductions in microfilaraemia after ML treatment but possess an ML-susceptible genotype.

Equine physiotherapy commonly includes basic exercises such as walking backward (BW) and voluntary lifting of single limbs (SLL), but trunk movements during these have not been studied. In order to compare the trunk kinematics during BW and SLL with forward walking (FW), nine horses were measured in FW, BW and during SLL triggered by tactile cue. Kinematics were obtained from skin markers captured by ten high-speed video cameras. Trunk angles were calculated in sagittal and horizontal planes from withers, dorsal to spinous processes of the 16th thoracic vertebra (T16), 2nd and 4th sacral vertebrae (S2, S4), WT16S2 and T16S2S4 respectively. From the hooves, maximum hoof height during swing phase and horizontal distance between hoof and median body plane during swing and stance phases were determined.

Dorsoventral range of motion (ROM) and maximum flexion of WT16S2 was significantly larger in BW than in FW, while laterolateral ROM was significantly smaller during hindlimb swing phase in BW and SLL than in FW. In contrast, dorsoventral ROM of T16S2S4 was significantly smaller during stance and swing phases of hindlimbs in BW compared to FW, and throughout the movement. During forelimb swing phase, T16S2S4 ROM was significantly larger in BW than SLL. Hindhoof height in SLL was significantly higher than in FW. Distance between median body plane and hooves was significantly larger in BW than in FW, and significantly larger in BW than in SLL for hindlimb swing phase. In BW, increased lumbosacral stabilisation and the larger area of support created by fore- and hindlimbs may represent a strategy to enhance body stabilisation, as BW entails some insecurity.