Relationships between admissions requirements and pre-clinical and clinical performance in a distributed veterinary curriculum

The purpose of this study was twofold: first, to assess the relationships between knowledge-based admission requirements and pre-clinical and clinical performance in a distributed model of veterinary education that uses problem-based learning as the main instruction method in the first two years of the curriculum; second, to compare pre-clinical and clinical performance with performance on the Program for the Assessment of Veterinary Education Equivalence (PAVE) exam. Admissions data including overall GPA, prerequisite GPA, Graduate Record Examination (GRE) score on the Analytical, Analytical Writing, Quantitative, and Verbal sections), veterinary school performance data (GPA for pre-clinical and clinical years), and performance PAVE (taken at the end of second year) were analyzed for two classes (N = 155, 85.8% women and 14.2% men). Overall GPA, prerequisite GPA, and GRE Quantitative and Analytical scores were the best predictors for pre-clinical (years 1 and 2) performance (R = 0.49, 23.5% of the variance), GRE Analytical score was the best predictor for year 3 (pre-clinical and clinical) performance (R = 0.25, 6.3% of the variance), GRE Quantitative score was the best predictor for PAVE performance (R = 0.27, 7.5% of the variance), and GRE Analytical score was the best predictor for clinical performance (year 4; R = 0.21, 4.4% of the variance). PAVE scores correlated with GRE Quantitative scores (r = 0.27, p <.01) and veterinary school performance, with higher correlations in the pre-clinical years (rs = 0.67-0.36, p < .01), providing evidence of convergent validity for the PAVE exam.     

Effects of clopidogrel and aspirin on platelet aggregation, thromboxane production, and serotonin secretion in horses

Background: Critically ill horses are susceptible to thrombotic disease, which might be related to increased platelet reactivity and activation. Objectives: To compare the effect of oral clopidogrel and aspirin (ASA) on equine platelet function. Animals: Six healthy adult horses. Methods: Horses received clopidogrel (2 mg/kg PO q24h) or ASA (5 mg/kg PO q24h) for 5 days in a prospective randomized cross‐over design. Platelet aggregation responses to adenosine diphosphate (ADP) and collagen via optical aggregometry, and platelet secretion of serotonin (5HT) and production of thromboxane B₂ (TXB₂) by ELISA were evaluated. In horses receiving clopidogrel, high‐performance liquid chromatography analysis for clopidogrel and its carboxylic‐acid metabolite SR 26334 was performed. Results: SR 26334 was identified in all clopidogrel‐treated horses, although the parent compound was not detected. Clopidogrel resulted in decreases in ADP‐induced platelet aggregation persisting for 120 hours after the final dose. ADP‐induced platelet aggregation decreased from a baseline of 70.2 ± 14.7% to a minimum of 15.9 ± 7.7% 24 hours after the final dose (P < .001). Collagen‐induced aggregation decreased from a baseline of 93 ± 9.5% to a minimum of 70.8 ± 16.9% 48 hours after the final dose (P < .001). ASA did not decrease platelet aggregation with either agonist. ASA decreased serum TXB₂ from a baseline value of 1310 ± 1045 to 128 ± 64 pg/mL within 24 hours (P < .01). Conclusions and Clinical Importance: Clopidogrel effectively decreases ADP‐induced platelet aggregation in horses, and could have therapeutic applications for equine diseases associated with platelet activation.     

A pilot study to assess tolerability of early enteral nutrition via esophagostomy tube feeding in dogs with severe acute pancreatitis

Background: The putative role of the gut in amplification of systemic inflammation in acute pancreatitis is gaining credence, and intraluminal nutrition has been shown to decrease inflammation in experimental models of pancreatitis. Prepyloric feeding often is used in people with acute pancreatitis, but has not been evaluated in dogs. Hypothesis: Early intervention with enteral nutrition (EN) delivered proximal to the pylorus will be well tolerated in dogs with acute pancreatitis and provide justification for further larger trials. Animals: Ten dogs with severe acute pancreatitis in an open‐label, prospective pilot study. Methods: Dogs were treated with plasma transfusion and standard care, and then consecutively assigned to receive either EN via esophagostomy tube feeding or parenteral nutrition (PN). Outcome was used to determine optimal study size for future studies, and complications were compared between the 2 groups. Results: A significantly greater number of vomiting or regurgitating episodes occurred in dogs receiving PN. The dogs receiving EN did not demonstrate any noticeable postprandial pain. There were more catheter‐related complications in the PN group. There was no difference in outcome between the 2 treatments, and 43 dogs for each treatment would be required in future studies to determine a difference in outcome. Conclusions and Clinical Relevance: Early EN delivered proximal to the pylorus is well tolerated in dogs with severe pancreatitis and resulted in fewer complications than PN. Prospective trials in a larger cohort are justified to fully establish the potential benefit of early EN, preferably compared with minimal enteral nutrition.     

In vitro effect of ventriculocordectomy before laryngoplasty on abduction of the equine arytenoid cartilage

Objective: To determine whether ventriculocordectomy (VCE) performed before prosthetic laryngoplasty (PL) results in increased rima glottidis size compared with PL alone. Study Design: Experimental study. Animals: Equine cadaver larynges (n=13). Methods: Right arytenoid cartilages were maximally abducted using a standard PL technique. Standard PLs were then performed on the left side and the force required to maximally abduct the left arytenoid cartilage recorded (F_max). Photographs were taken of the rima glottidis at zero force and at five equal levels of force up to F_max. The force applied was released, left VCE performed, and photographs repeated. Arytenoid left:right angle quotients (LRQ) and glottic cross‐sectional area ratios (CSAR) were calculated at each force level in each condition (PL and VCE‐PL). Results: Mean LRQ and CSAR for both PL and VCE‐PL increased with increasing force, initially rapidly before plateauing at ～50% of F_max. LRQ and CSAR were significantly greater for VCE‐PL than for PL (P<.001). When VCE was performed before PL, 12% less force was required to achieve an LRQ of 0.8, and 45% less for a CSAR of 0.8. Conclusions: In vitro, VCE performed before PL enables the arytenoid cartilage to be abducted to a greater degree for a given PL suture force.     

Brave or gullible: testing the concept that leaving susceptible parasites in refugia will slow the development of anthelmintic resistance

AIM: To test the theory that creating a reservoir of unselected worms by leaving a proportion of lambs in a flock untreated with anthelmintic, i.e. in refugia, will slow the development of anthelmintic resistance in nematode parasite populations. METHODS: Newly weaned Romney lambs (n=180) were infected with two nematode parasite species, Teladorsagia (= Ostertagia) circumcincta and Trichostrongylus colubriformis. For each species, the challenge doses contained a mixture of infective larvae from benzimidazole-resistant and -susceptible isolates calculated to yield, from the combined population, a 95% reduction in faecal nematode egg counts (FEC) following treatment with albendazole. Once the infections were patent, the lambs were divided into nine groups of 20 animals, and each group was allocated to one of three treatments. In Treatments 1, 2 and 3, 100%, 90% and 80% of animals were treated with an anthelmintic, respectively. For treatments 2 and 3, the heaviest animals remained untreated. Following treatment, each group was moved to its own previously prepared low-contamination pasture. Lambs grazed this pasture for 7 weeks before again being treated and moved to new low-contamination pastures (Shift 1 and Shift 2). The parasite populations on pasture resulting from the different treatments were subsequently sampled using tracer lambs, and worm eggs derived from these were used in both egg-hatch assays (EHA) and larval development assays (LDA), to measure albendazole-resistance status. RESULTS: Treating all animals each time the groups were moved to new low-contamination pastures resulted in higher levels of albendazole resistance (p<0.05), measured using EHA and LDA, in subsequent parasite generations than when either 10 or 20% of animals were left untreated. However, higher FEC in the tracer lambs grazed on pastures in Treatments 2 and 3, compared with Treatment 1, indicated an increased level of pasture contamination as a result of leaving some animals untreated. CONCLUSIONS: The results demonstrate that creating a reservoir of unselected parasites slows the development of anthelmintic resistance, and emphasises the risk of treating all animals prior to a shift on to low-contamination pasture. However, higher levels of pasture contamination, resulting from untreated animals, indicate the difficulty in managing both worm control and resistance.     

Morphometrical approach for predicting regional lymph node micrometastatic load in canine mast cell tumours: preliminary results

Canine cutaneous mast cell tumours (MCTs) have a variable biologic behaviour, and accurate staging is necessary to dictate therapy and predict outcome. Regional lymph node (RLN) involvement is a relevant prognostic factor. While obvious lymph node (LN) metastases are relatively easy to be diagnosed, micrometastatic disease recognition is challenging. The main aim of the study was to evaluate the number of mast cells (MCs) in the LNs of clinically healthy dogs ( n = 4, group 1), dogs with inflammatory diseases ( n = 31, group 2) and dogs with cutaneous MCT ( n = 27, group 3), including animals with no RLN metastases (subgroup 3.1), those with occasional MCs in RLNs (3.2) and those with obvious RLN metastasis (3.3). MCs also were morphometrically evaluated for the following nuclear parameters: mean nuclear area (MNA), mean nuclear perimeter (MNP), largest to smallest diameter length (LS ratio), mean nuclear form factor and coefficient of variation of nuclear area. The average percentages of MCs were 0.0 and 0.01 in groups 1 and 2, respectively, and 0.07, 2.4 and 47.1 in subgroup 3.1, 3.2 and 3.3. MNA and MNP were significantly higher in subgroup 3.3 than in group 2 ( P < 0.05). MNA and MNP in subgroup 3.2 suggested the presence of neoplastic MCs; this prediction of micrometastatic load correlated with outcome. Analysis of preliminary results shows that nuclear morphometry is useful to detect micrometastatic disease in RLN of dogs bearing cutaneous MCTs.     

An analysis of the performance characteristics of serological tests for the diagnosis of Neospora caninum infection in cattle

AIMS: To analyse the performance characteristics (sensitivity/specificity) of two enzyme-linked immunosorbent assays (ELISA) against the indirect fluorescent antibody test (IFAT). METHODS: A total of 1199 sera were tested in two ELISAs and the IFAT and results analysed utilising software that performed a receiver-operating characteristic (ROC) analysis. RESULTS: Sensitivity and specificity for the two ELISAs were calculated for a range of different cut-offs. Minimal misclassification was achieved at cut-offs that, in the case of the Central Animal Health Laboratory (CAHL)-ELISA were in line with previously published cut-off values. In the case of the IDEXX-ELISA lower cut-off values than suggested by the manufacturer were calculated. CONCLUSIONS: ROC-analysis resulted in optimised, as compared to the IFAT, cut-off thresholds for the CAHL and IDEXX-ELISA which can be further adjusted depending on the purpose of the investigation.     

Blood plasma concentrations of oestradiol-17beta,testosterone and testosterone/oestradiol ratio in dogs with neoplastic and degenerative testicular diseases

Oestradiol-17beta and testosterone blood plasma concentrations were measured in dogs with Leydig-cell tumours (n=20), Sertoli-cell tumours (n=6), seminomas (n=9), unilateral inguinal cryptorchidism (n=7), abdominal cryptorchidism (n=9, one bilateral), degenerate scrotal testicles (n=6, two bilateral), and animals with normal scrotal testicles (n=20). The testosterone/oestradiol ratio (testosterone concentration [ng/mL]x100/oestradiol concentration [pg/mL]) was calculated.A considerably higher oestradiol concentration was found in dogs with Sertoli-cell tumours (29.0, 14.4-48.3 pg/mL; median, minimum-maximum; P=0.0256, Mann-Whitney test) and lower oestradiol levels were found in animals with seminomas (12.0, 3.4-17.6 pg/mL; P=0.0025) compared to the healthy control group (18.0, 8.6-31.5 pg/mL). Testosterone concentration was decreased in dogs with Sertoli-cell tumours (0.08, 0.03-0.77 ng/mL) when compared to the control group (1.95, 0.05-3.70 ng/mL; P=0.0012). Testosterone/oestradiol ratios differed from the control (9.6, 0.58-35.8) only in dogs with Sertoli-cell tumours (0.32, 0.06-2.80; P=0.0005). Clinical signs of feminization were observed in five dogs with Sertoli-cell tumour and one dog with a Leydig-cell tumour, and were more often associated with decreased testosterone/oestradiol ratios than with an increased oestradiol-17beta concentration.     

蛋鸡的一种潜在性病原

澳大利亚 Murdoch大学兽医和生物医学部的 D.J.Hampson等从澳大利亚 1只患腹泻的母鸡体中分离出了 1种厌氧性螺旋体 - Serpulina in-termedia,并将其通过嗉囊给 1 0只单独笼养的 1 4周龄母鸡接种 ,给其他 1 0只鸡喂服无菌肉汤作为对照。试验持续 1 6周 ,并对试验鸡的粪水内容物、产蛋量和体重进行了测量。在试验期间 ,从 9只感染鸡的粪便及屠宰时的盲肠中分离出了 Serpuli-na intermedia HB60株。感染鸡表现为体重轻 ,粪便较湿 ,产蛋量及蛋的重量都小于对照组。但并未见明显的病理学变化。由此表明 ,Serpulina intermedia有可能由于导致…