Performance comparison of 159 Thoroughbred racehorses and matched cohorts before and after desmotomy of the interspinous ligament.

Racehorses may perform poorly because of impinging dorsal spinous processes (DSPs) of the thoracolumbar vertebrae. No study has looked objectively at the long-term outcome of racehorses undergoing desmotomy of the interspinous ligament as a treatment for horses with poor performance caused by impinging DSPs. The aim of this study was to examine objectively, by using pre-operative and post-operative racing records, the effectiveness of desmotomy of the interspinous ligament (DISL) in improving the performance of racehorses with impinging DSPs. Medical records of all horses undergoing desmotomy of one or more interspinous ligaments at a referral equine hospital, between February 2015 and September 2016, were reviewed. The study was confined to Thoroughbred racehorses with sufficient historical information and racetrack data to allow their racing performances be compared to that of matched controls. Matched controls were of the same age, sex, and racing type and were trained at the same time by the same trainer as those undergoing desmotomy. The time to follow-up was at least 12 months. Of the 6545 horses presented for poor performance or lameness during the study period, 236 horses (3.6%) underwent desmotomy of one or more interspinous ligaments, and of these, 159 met the inclusion criteria. Horses undergoing desmotomy had significantly better improvement in racing performance than did matched controls. Eight horses developed unilateral neurogenic atrophy of epaxial musculature. DISL between impinging DSPs can improve the performance of racehorses experiencing from poor performance caused by pain resulting from the impinging processes.

Hands-on Gross Anatomy Instruction Improves Clinical Imaging Skills Among Cardiovascular Fellows.

INTRODUCTION: Multi-modality imaging is a crucial component of cardiovascular (CV) fellowship training and requires knowledge of CV anatomy for interpretation. We hypothesized that hands-on anatomy education would improve the imaging interpretation skills of CV fellows. METHODS: The first-year CV fellowship class completed a hands-on cadaveric anatomy session correlated with clinical imaging. Fellows' ability to identify CV structures on cardiac imaging was assessed using a 30-question assessment tool administered at baseline and 1 week and 6 months post intervention. Advanced CV fellows (second or third year) who had not attended the session were also tested. Scores were expressed as median [interquartile range]. RESULTS: Among 9 first-year fellows, the majority reported no formal anatomy training since medical school (N = 7) and rated their knowledge of CV anatomy as fair or poor (N = 7) prior to the intervention. The median assessment score was higher 1 week after intervention vs baseline (24 [23-25] vs 19 [17-21]; P = .013) and remained higher than baseline at 6 months (26 [26-28] vs 19 [17-21]; P = .009). The 6-month post-intervention score for first-year fellows was not significantly different than that of senior fellows (n = 10) not exposed to the intervention (26 [26-28] vs 26 [23-27]; P = .434). CONCLUSIONS: Gross anatomy instruction improved first-year CV fellows' interpretation of CV imaging. Anatomic instruction may be a useful adjunct to multi-modality imaging education.

Kidney dysfunction in patients with pulmonary arterial hypertension.

Pulmonary arterial hypertension (PH) and chronic kidney disease (CKD) both profoundly impact patient outcomes, whether as primary disease states or as co-morbid conditions. PH is a common co-morbidity in CKD and vice versa. A growing body of literature describes the epidemiology of PH secondary to chronic kidney disease and end-stage renal disease (ESRD) (WHO group 5 PH). But, there are only limited data on the epidemiology of kidney disease in group 1 PH (pulmonary arterial hypertension [PAH]). The purpose of this review is to summarize the current data on epidemiology and discuss potential disease mechanisms and management implications of kidney dysfunction in PAH. Kidney dysfunction, determined by serum creatinine or estimated glomerular filtration rate, is a frequent co-morbidity in PAH and impaired kidney function is a strong and independent predictor of mortality. Potential mechanisms of PAH affecting the kidneys are increased venous congestion, decreased cardiac output, and neurohormonal activation. On a molecular level, increased TGF-ß signaling and increased levels of circulating cytokines could have the potential to worsen kidney function. Nephrotoxicity does not seem to be a common side effect of PAH-targeted therapy. Treatment implications for kidney disease in PAH include glycemic control, lifestyle modification, and potentially Renin-Angiotensin-Aldosterone System (RAAS) blockade.

Intra- and interobserver reliability estimates for identification and grading of upper respiratory tract abnormalities recorded in horses at rest and during overground endoscopy.

BACKGROUND: Previous studies support good intra- and interobserver agreements for endoscopic evaluation of various upper respiratory tract (URT) diseases in horses. However, these studies mainly assessed resting endoscopic examination videos and/or focussed on a single URT abnormality. OBJECTIVES: To estimate intra- and interobserver agreement for identification and grading of all URT abnormalities from resting and overground endoscopy (OGE) videos of Thoroughbreds. STUDY DESIGN: Blinded, fully crossed design. METHODS: Resting and OGE URT videos for n = 43 Thoroughbreds were retrospectively chosen based on identification of common URT disorders. The videos were randomly evaluated in duplicate by 4 raters blinded to all information including prior URT disorder(s) diagnosis. Abnormalities were graded using well-described ordinal scales. Intra- and interobserver agreements were estimated using Cohen's weighted κ and Krippendorff's α, respectively. RESULTS: Intraobserver agreement was perfect/nearly perfect for arytenoid symmetry at exercise, epiglottic entrapment and epiglottic retroversion, substantial for arytenoid asymmetry at rest, palatal dysfunction (PD), medial deviation of the aryepiglottic folds (MDAF), pharyngeal mucus and epiglottic grade at exercise and moderate for vocal fold collapse (VFC), ventromedial luxation of the apex of the corniculate process of the arytenoid (VLAC), nasopharyngeal collapse (NPC) and epiglottic grade at rest. Interobserver agreement was substantial for arytenoid symmetry at exercise and PD and moderate for arytenoid asymmetry at rest, MDAF, VLAC and epiglottic entrapment. It was only fair for VFC, epiglottic grade at exercise, epiglottic retroversion, pharyngeal mucus and NPC and poor for epiglottic grade at rest. MAIN LIMITATIONS: Sample size was insufficient to allow assessment of the effect of one abnormality on the grading of another abnormality. CONCLUSIONS: Observers were consistent in grading URT disorders. However, significant disparity in grading existed between observers for some conditions affecting reliability.

Characterisation of palatal dysfunction after laryngoplasty.

REASONS FOR PERFORMING STUDY: Dorsal displacement of the soft palate (DDSP) in the horse has been previously described as intermittent, typically occurring at fast exercise; or persistent, seen at rest. Dorsal displacement of the soft palate has recently been reported following laryngoplasty (LP) and can be associated with continued poor performance and respiratory noise. OBJECTIVES: The current study aimed to characterise the DDSP diagnosed post LP. STUDY DESIGN: Cross-sectional study. METHODS: Owners/trainers of horses undergoing LP at one institution over 6 years were contacted to determine the horse's progress and willingness for re-examination. The horses were examined at the rest, walk, trot and canter with an overground exercising endoscope. A GPS-equipped watch was carried to obtain maximal exercising speeds. Videos of horses with DDSP were reviewed to determine frequency and duration of DDSP and swallowing events at the various gaits. RESULTS: Exercising endoscopy was performed in 41 of the 89 horses that had undergone LP. Nineteen of the 41 horses were diagnosed with DDSP at exercise, of which 7/41 also had DDSP at rest. No difference was detected in the percentage of total time spent displaced at each gait (P = 0.67), or in the frequency of new DDSP events per minute between each gait (P = 0.10), or in the frequency of swallowing events per minute between each gait (P = 0.52). The majority of horses displaced at various times throughout each gait. Dorsal displacement of the soft palate was most commonly solely induced spontaneously and always corrected with a swallow. The maximum speed achieved was 8.3 m/s. CONCLUSIONS: Dorsal displacement of the soft palate was common following LP and it appears to be induced at slower gaits than DDSP that has previously been described. It also occurred at various times throughout each gait and did not always occur persistently at rest. POTENTIAL RELEVANCE: These findings suggest horses undergoing LP may be more prone to DDSP and further investigations into the aetiology of post LP palatal dysfunction are warranted.

A long-term study on the clinical effects of mechanical widening of cheek teeth diastemata for treatment of periodontitis in 202 horses (2008-2011).

REASON FOR PERFORMING STUDY: Cheek teeth diastemata are a common cause of painful periodontal disease in horses, but there is limited objective information on their treatment. OBJECTIVE: To assess the long-term response to diastema widening in clinically affected horses. STUDY DESIGN: Retrospective study. METHOD: Medical records from cases of cheek teeth diastemata treated by diastema widening referred to the University of Edinburgh Equine Hospital from 2008 to 2011 were analysed. RESULTS: During this period, 302 horses were diagnosed with clinically significant cheek teeth diastemata, of which 202, median age 11 years, with severe associated periodontitis were treated by widening of 674 problematic diastemata; 89.8% between mandibular cheek teeth and 10.2% between maxillary cheek teeth, with a mean of 1.5 treatments performed per case. These 202 cases showed quidding in 76.2%; weight loss in 33.2%; bitting problems in 20.1% and halitosis in 10.9%, with 5.4% being asymptomatic. Follow-up of 92% of treated cases, a mean of 20.8 months after their initial treatment, showed that 72.6% had complete remission of clinical signs that was permanent (for the duration of this study) in 50.5% and temporary in 22%. A partial response was obtained in 17.2%, no response was obtained in 4.3%, and owners were unsure of response in 5.9%. Clinical improvement was sometimes delayed, with 19% taking >4 weeks following treatment for improvement. Inappropriate sites were burred in individual teeth of 6 horses, causing iatrogenic pulpar exposure in 2 cases, but following treatment none developed clinical signs of apical infection. CONCLUSIONS: Diastema widening is an effective but potentially invasive treatment for horses with cheek teeth diastemata with severe periodontitis. POTENTIAL RELEVANCE: Diastema widening by trained personnel is suitable for advanced cases of cheek teeth diastema, but many cases require repeated treatments.

Long-term exercising video-endoscopic examination of the upper airway following laryngoplasty surgery: a prospective cross-sectional study of 41 horses.

REASONS FOR PERFORMING STUDY: To investigate upper respiratory tract function in horses, previously undergoing laryngoplasty (LP), using exercising video-endoscopy. OBJECTIVES: To evaluate arytenoid abduction and stability, diagnose any concurrent upper airway problems, and correlate these with the owners' perception of success. METHODS: Horses undergoing LP during a 6-year period at one hospital were initially included. Those available for re-examination were exercised for a duration and intensity considered maximal for their discipline using an over-ground endoscope. Resting and exercising laryngeal and pharyngeal videos were analysed blindly. Multivariable analysis was used to test associations between resting and exercising endoscopic variables, and also between endoscopic variables and owner questionnaire findings. RESULTS: Forty-one horses were included and 78% had a form of upper airway collapse at exercise, with 41% having complex forms, despite 93% of owners reporting the surgery to have been beneficial. Horses with poor abduction (grades 4 or 5/5) were 6 times more likely to make respiratory noise compared with those with good (grades 2 or 3/5) abduction (P = 0.020; 95% confidence interval [CI] 1.3-27.0), and those not having a ventriculectomy were 4.9 times more likely to produce respiratory noise post operatively (P = 0.048; 95% CI 1.0-23.9). Palatal dysfunction was observed in 24% of horses at rest, and 56% at exercise, with the diagnosis at rest and exercise significantly associated (P = 0.001). Increasing severity of pharyngeal lymphoid hyperplasia (prevalence 61%) was significantly associated with increasing arytenoid abduction (P = 0.01). Thirty-four per cent of horses had aryepiglottic fold collapse and 22% of horses had vocal fold collapse. CONCLUSIONS: Many horses that had previously had LP were diagnosed with upper airway abnormalities, despite the procedure being considered as beneficial by most owners. POTENTIAL RELEVANCE: When investigating cases of ongoing respiratory noise or poor performance following LP, exercising endoscopy must be considered. Continued respiratory noise may be associated with poor arytenoid abduction and not performing concurrent ventriculectomy.

Pulpar temperature changes during mechanical reduction of equine cheek teeth: comparison of different motorised dental instruments, duration of treatments and use of water cooling.

REASONS FOR PERFORMING STUDY: Although equine motorised dental instruments are widely used, there is limited information on their thermal effect on teeth. The recently described variation in subocclusal secondary dentine depth overlying individual pulp horns may affect heat transmission to the underlying pulps. OBJECTIVES: This study compared the effect of 3 different equine motorised dental instruments on the pulpar temperature of equine cheek teeth with and without the use of water cooling. It also evaluated the effect of subocclusal secondary dentine thickness on pulpar temperature changes. METHODS: A thermocouple probe was inserted into the pulp horns of 188 transversely sectioned maxillary cheek teeth with its tip lying subocclusally. Pulpar temperature changes were recorded during and following the continuous use of 3 different equine motorised dental instruments (A, B and C) for sequential time periods, with and without the use of water cooling. RESULTS: Using motorised dental instrument B compared with either A or C increased the likelihood that the critical temperature was reached in pulps by 8.6 times. Compared with rasping for 30 s, rasping for 45, 60 and 90 s increased the likelihood that the critical temperature would be reached in pulps by 7.3, 8.9 and 24.7 times, respectively. Thicker subocclusal secondary dentine (odds ratio [OR] = 0.75/mm) and water cooling (OR = 0.14) were both protective against the likelihood of the pulp reaching the critical temperature. CONCLUSIONS: Prolonged rasping with motorised dental instruments increased the likelihood that a pulp would be heated above the critical temperature. Increased dentinal thickness and water cooling had protective roles in reducing pulpar heating. POTENTIAL RELEVANCE: Motorised dental instruments have the potential to seriously damage equine pulp if used inappropriately. Higher speed motorised dental instruments should be used for less time and teeth should be water cooled during or immediately after instrument use to reduce the risk of thermal pulpar damage.

Conservation of hydrophobicity within viral envelope glycoproteins reveals a putative hepatitis C virus fusion peptide.

The mechanism(s) by which hepatitis C virus (HCV) enters and infects cells remains unknown. Identifying the HCV fusion peptide(s) and understanding the early stages of infection may provide new opportunities for improved antiviral therapy. The HCV envelope glycoprotein E2 is thought to be a class II fusion protein. Class II fusion proteins are exemplified by the E protein of the tick-borne encephalitis virus (TBEV) and the E1 protein of the Semliki Forest virus (SFV). Analysis of the hydrophobicity profiles of four HCV E2 envelope glycoproteins revealed a region with a conserved three-pronged pattern of hydrophobicity, termed the tridentate (TD) region. The primary sequence of the TD region is highly conserved in all 490 HCV strains currently reported. The known fusion peptide loops of TBEV and SFV share the characteristic TD region hydrophobicity profile and significant sequence conservation in the TD region was identified in the E and E1 glycoproteins of members of the Flaviviridae and Togaviridae families, respectively. The HCV TD region peptides have membranotropic activity; in molecular dynamics (MD) simulations, the HCV TD region peptides insert into in a biomimetic bilayer in a similar manner to the TBEV fusion peptide and the peptides induce effective mixing of lipid membranes in a liposome fusion assay. Together these results indicate that the highly conserved TD region of the HCV E2 protein is a fusion peptide candidate and may be an important factor in the class II fusion mechanism.