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Biomedical subjects

S A May

Publications and source records attributed to S A May.

At least 19 recordsLinked to original sources
PubMed2006

Evidence of bias affecting the interpretation of the results of local anaesthetic nerve blocks when assessing lameness in horses.

Eighteen observers were influenced to different extents in the grades of lameness they allocated to eight horses by whether they knew that a nerve block had been administered; on a scale from 0 to 10 the mean difference in grade allocated once the observer knew a horse had been nerve-blocked was increased by 0.4. The consistency of the assessments made by the individual observers was good, with a an average of 0.6 of a grade difference when grading the same horse on two occasions. The agreement between the assessments of four orthopaedic experts was reasonable (+/-1 grade), but significantly poorer for four non-experts and 10 final year veterinary students.

Animals↗
PubMed2006

Reliability of conformational measurements in the horse using a three-dimensional motion analysis system.

REASONS FOR PERFORMING STUDY: The importance of a reliable method for conformation studies is generally acknowledged, but there are only limited data on the accuracy and precision of current assessment methods. OBJECTIVES: To assess (1) the accuracy and repeatability of marker placement, (2) influence of stance of the horse on conformational parameters, (3) practicality of a computerised motion analysis system and (4) to compare the computerised motion analysis system to photographic systems of assessment. METHODS: Twenty-eight reflective markers placed over anatomical landmarks were located in 3D using a computerised motion analysis system and their coordinates used to calculate segment lengths and joint angles. Four experiments, involving a cadaver study, a series of repeated measures on a single Thoroughbred and repeat measurements on 108 racehorses were performed. RESULTS: Identification of anatomical landmarks was found to introduce the biggest variation in the measurements for proximal conformation parameters with the interoperator being larger than intraoperator variation. Length measurements were least influenced by stance, with distal interphalangeal and metacarpo/metatarsophalangeal joint angles being the most variable. In some measurements, the variation between stances within a horse proved to be almost as large as between horses, rendering these parameters less useful as predictors of performance or orthopaedic health. CONCLUSIONS: A computerised motion analysis system allows 3D assessment of conformation with high accuracy and precision. It eliminates 3 major sources of error associated with photography-based methods and increases accuracy of conformational assessment by allowing repeat measurements in a relatively short period. POTENTIAL RELEVANCE: Studies on conformation should be viewed in the light of the limitations of the measurement technique used. The presented method maximises accuracy and precision and is a valuable basis for future studies investigating the effect of conformation on performance or orthopaedic health.

Animals↗
PubMed2006

Variation in conformation in a cohort of National Hunt racehorses.

REASONS FOR PERFORMING THE STUDY: Assessment of conformation is commonly used in the selection of horses for performance purposes. Little information is available on the normal range of conformational traits within the Thoroughbred population. OBJECTIVES: To describe variations in conformation in a cohort of racing Thoroughbreds in order to provide a set of baseline standards within which conformational traits can be considered normal. MATERIALS AND METHODS: Ninety-eight conformational parameters were measured in a cohort of 108 National Hunt racehorses using a digital motion analysis system. The measurements consisted of segment lengths, joint angles in 2D and 3D, inclinations, deviations and circumference measurements. The differences between left and right sides were determined to obtain a measure of asymmetry. Conformational parameters were related to each horse's country of origin, preferred race distance and race type. RESULTS: The majority of parameters followed a normal distribution with the biggest relative variation in hoof related measurements and in stifle and coxal angle. All circumference measurements and the majority of the length measurements were significantly correlated with the height of the horse at the withers. No underlying pattern of combinations of conformational parameters was identified. Twenty-five per cent of the parameters showed a significant difference between left and right-sided measurements. A significant difference in girth and intermandibular width was observed between Irish and French horses. CONCLUSIONS: Thoroughbreds differ from other breeds, not only with regard to segment lengths but also with regard to joint angles and deviations. Variation in conformational parameters was relatively small and no distinct pattern of combinations of conformational traits identified. CLINICAL RELEVANCE: The variation in conformational measurements in Thoroughbred racehorses establishes a set of baseline measurements of conformational range against which individual horses can be assessed.

Animals↗
PubMed2006

The effect of conformation on orthopaedic health and performance in a cohort of National Hunt racehorses: preliminary results.

REASONS FOR PERFORMING STUDY: There is a lack of scientific data and studies on the effect of conformation on performance or on orthopaedic health. OBJECTIVES: To investigate the relationship between conformation, injury and performance in racehorses used for racing over fences. METHODS: Over 2 years, 108 National Hunt racehorses were followed and their medical and performance data recorded. Conformation was measured in 3D with a computerised motion analysis system. Linear multiple regression models were used to evaluate the effect of conformation on measures of race performance and stepwise forward logistic regression models to assess the effect on risk of injury. RESULTS: An increase in intermandibular width, flexor angle of the shoulder joint and coxal angle (the angle between the ilium and ischium) was demonstrated to have a positive effect on performance. Performance decreased with increasing girth, length of the hind digit and valgus conformation of the metacarpophalangeal joint. The risk of suffering from superficial digital flexor tendon injury increased with increasing metacarpophalangeal joint angle and with carpus valgus conformation. The risk of pelvic fracture increased with valgus conformation of the tarsus and decreased with an increasing coxal angle. CONCLUSION: Valgus deformation was demonstrated to be detrimental to performance or increased risk of injury, perhaps resulting in higher loads on musculoskeletal structures. The coxal angle was the only parameter to have an effect on both risk of injury and performance. An alignment of the muscles with the axis of the pelvis may be beneficial for force transmission and decrease the bending moment of the muscles on the bones. The statistical power of this study is limited, however it provides preliminary data necessary for the planning of a larger scale study on the effect of conformation on performance and risk of injury. CLINICAL RELEVANCE: Studies of the effects of conformation on performance and risk of injury may aid in identifying individuals likely to perform well on the racecourse and avoid risks of injury.

Animals↗
PubMed2004

Relationship between acute phase proteins and hoof horn haemorrhages in postpartum first-lactation heifers.

As part of a study of the development of hoof horn haemorrhages in first-lactation heifers, measurements were made of acute phase reactants to investigate the link between the acute phase response and the development of the haemorrhages. Over a period of two years, blood samples were taken from two separate groups of heifers, weekly in the three weeks before they calved and then twice weekly until eight weeks after calving. Plasma total protein, albumin, fibrinogen, haptoglobin, seromucoid and serum iron and caeruloplasmin were measured and the relationships between the peak concentration (or activity) or the area under the curve of each acute phase reactant and the peak scores for sole or white line haemorrhages were assessed by linear regression. The results suggested that the development of the hoof horn haemorrhages observed in the study was not accompanied by an acute phase response, and the haemorrhages were therefore not primarily caused by endotoxicosis. The diets and husbandry systems used were typical of dairy farms in the UK and the results therefore suggest that a significant proportion of hoof horn haemorrhages observed in UK dairy cows may not be caused by endotoxicosis.

Acute-Phase Proteins↗
PubMed2004

Tenocyte response to cyclical strain and transforming growth factor beta is dependent upon age and site of origin.

The effect of strain and transforming growth factor beta on equine tendon fibroblasts (tenocytes) was assessed in vitro. Tenocytes were isolated from flexor and extensor tendons of horses from foetal to 10 years of age. These cells were cultured until confluent on collagen-coated silicone dishes. Cyclic biaxial strain of 9+/-1% was applied at 0.5 Hz for 24 hours with or without added TGFbeta1 or 3 (10 ng/ml). Proliferation and synthetic responses were dependent on the tendon of origin. Neither strain nor TGFbeta caused flexor tenocytes to proliferate significantly, while strain alone did proliferate extensor tenocytes. TGFbeta, with or without strain, increased the incorporation of [3H]-proline and the production of types I and III collagen and COMP in both cell types, although the effect on COMP production was more marked in flexor tenocytes, perhaps reflecting the higher levels found in this tendon in vivo. Immature flexor tenocytes synthesised more collagen and COMP than those from mature animals, while age had little effect in extensor tenocytes. Our results suggest that tenocytes become differentiated at an early age and present tendon-specific responses.

Aging↗
PubMed2003

Biochemical characterisation of navicular hyaline cartilage, navicular fibrocartilage and the deep digital flexor tendon in horses with navicular disease.

The study hypothesis was that navicular disease is a process analogous to degenerative joint disease, which leads to changes in navicular fibrocartilage and in deep digital flexor tendon (DDFT) matrix composition and that the process extends to the adjacent distal interphalangeal joint. The objectives were to compare the biochemical composition of the navicular articular and palmar cartilages from 18 horses with navicular disease with 49 horses with no history of front limb lameness, and to compare navicular fibrocartilage with medial meniscus of the stifle and collateral cartilage of the hoof. Cartilage oligomeric matrix protein (COMP), deoxyribonucleic acid (DNA), total glycosaminoglycan (GAG), metalloproteinases MMP-2 and MMP-9 and water content in tissues were measured. Hyaline cartilage had the highest content of COMP and COMP content in hyaline cartilage and tendon was higher in lame horses than in sound horses (p<0.05). The concentration of MMP-2 amount in hyaline cartilage was higher in lame horses than in sound horses. The MMP-2 amounts were significantly higher in tendons compared to other tissue types. Overall, 79% of the lame horses with lesions had MMP-9 in their tendons and the amount was higher than in sound horses (p<0.05). In horses with navicular disease there were matrix changes in navicular hyaline and fibrocartilage as well as the DDFT with potential implications for the pathogenesis and management of the condition.

Animals↗
PubMed2003

Effect of foot balance on the intra-articular pressure in the distal interphalangeal joint in vitro.

REASONS FOR PERFORMING STUDY: Increased joint pressure has been implicated in the progression of osteoarthritis. HYPOTHESIS: That intra-articular pressure in the distal interphalangeal joint (DIP) is significantly higher in legs loaded with heel up (HU), low heel (TU), lateral side up (LU) and medial side up (MU) imbalance compared to the balanced position. METHODS: Twelve elbow down limbs were compressed in a hydraulic loading jig and DIP pressure measured. RESULTS: Elevating the heels by 5 degrees significantly increased DIP pressure. After 5 ml of contrast was injected into the joint, heel elevation caused a greater increase in DIP pressure and heel lowering decreased DIP pressure. Silicone rubber castings were taken of 20 DIP whilst under load. The articular contact area was localised on the dorsal aspect in the HU position, palmar aspect in the TU position and towards the elevated side with lateromedial imbalance. CONCLUSIONS: Altered foot orientation, which could result from trimming and shoeing, therefore influences intra-articular pressure in the DIP and the articular contact area. POTENTIAL CLINICAL RELEVANCE: The results support the view that a balanced foot is the ideal and that the elevated heels may be detrimental to long term viability of the DIP joint.

Abattoirs↗
PubMed2001

Comparison of radiography and scintigraphy in the diagnosis of dental disorders in the horse.

Scintigraphy, with 99mTechnetium methylenediphosphonate (99mTc-MDP) and 99mTc-labelled leucocytes, was compared to radiography in the diagnosis of dental disease in the horse in a prospective case-controlled study, comprising 30 horses with clinical signs of dental disease and 30 control horses. In each case, right and left lateral, ventral and dorsal soft tissue and bone phase scintigraphic images were obtained after i.v. injection of 1 GBq/100 kg bwt 99mTc-MDP, using a gamma camera. The same views were acquired in 10 horses with clinical signs of dental disease and 12 control horses after injection of 99mTc-labelled leucocytes. Standard radiographic projections of the paranasal sinuses and of the apices of the maxillary and mandibular teeth were obtained. The scintigraphs and radiographs were assessed subjectively by 2 board-certified surgeons and one board-certified radiologist, with extensive experience of equine radiology, from who the clinical history was withheld. Sensitivity, specificity and kappa, as a measure of agreement, were calculated for the different methods. Bone phase images were also scored subjectively on a scale from 0 to 3 on the basis of isotope uptake over the teeth. Regions of interest were defined over the teeth, and normal teeth compared to diseased counterparts. Total scintigraphic counts were related to the age of the animal and to the disease process. Differences in density ratios between left and right teeth were evaluated using the Mann-Whitney Test. Dental disease was confirmed in 22 horses at surgery or postmortem examination. Horses with dental disease showed a significant increase in scintigraphic activity over the affected tooth compared to the contralateral tooth, with a typical pattern for different diseases. The sensitivity of scintigraphy with 99mTc-MDP proved to be excellent (95.5%), whereas the specificity was moderate (86.4%). In contrast, radiography had excellent specificity (95.0%) and a low sensitivity (51.5%). The greatest sensitivity and specificity were achieved by evaluating radiographs and scintigrams together. The objective scintigraphic density ratios were found to be significantly different between diseased and control horses. The results of this study suggest that, if a density ratio of 1.5 or greater between a suspected diseased tooth and its contralateral number is regarded as abnormal, only 1% false positive diagnoses and 20% false negative diagnoses will occur. In contrast, scintigraphy with 99mTc-labelled leucocytes was not very successful, due to the lack of anatomical detail provided by this technique, which made identification of the diseased tooth impossible. Accurate radiographic interpretation of dental disease presents difficulties, both in terms of missed diagnoses and mistaken diagnoses. Scintigraphy complements radiographic examination of dental structures by providing information important for accurate diagnosis and is, therefore, conceived to be essential for selection of the appropriate treatment for dental disease.

Animals↗
PubMed2000

Influence of interleukin-1beta and hyaluronan on proteoglycan release from equine navicular hyaline cartilage and fibrocartilage.

Proteoglycan (PG) release, in response to recombinant human interleukin-1beta (rh-IL-1beta), was measured in cartilage explants obtained from the equine distal sesamoid bone (navicular bone). Fibrocartilage from the surface of the navicular bone apposing the deep digital flexor tendon and hyaline cartilage from the surface of the navicular bone articulating with the middle phalanx were labelled with 35SO4. Hyaline cartilage from the distal metacarpus was used as a control tissue. Following radiolabel incorporation, the three cartilage types were treated with rh-IL-1beta (100 U/mL) in the presence of hyaluronan (0.2, 2, 20, 200 and 2000 microgram/mL). rh-IL-1beta-Induced PG release was measured by scintillation assay of PG-bound radiolabel. Increases in PG release of 94% (P < 0.01), 101% (P < 0.05) and 122% (P < 0.05), in response to rh-IL-1beta, were noted in fibrocartilage, navicular hyaline cartilage and metacarpal hyaline cartilage, respectively. Hyaluronan (0.2 microgram/mL) significantly reduced rh-IL-1beta-induced PG release in metacarpal hyaline cartilage (P < 0.01). In fibrocartilage and navicular hyaline cartilage, hyaluronan did not reduce PG release and at some concentrations appeared to increase PG release, although this was not statistically significant. These experiments show that (i) fibrocartilage and hyaline cartilage of the navicular bone release PGs in response to rh-IL-1beta, and (ii) hyaluronan does not prevent rh-IL-1beta-induced breakdown of navicular bone cartilage.

Adjuvants, Immunologic↗
PubMed2000

Electroencephalogram silence ratio for early outcome prognosis in severe head trauma.

OBJECTIVE: To introduce the electroencephalogram silence-ratio (ESR) as a variable derived from mathematically processed electroencephalogram for early outcome prognosis in patients with severe head trauma and to comparatively assess sensitivity, specificity and predictive value vs. somatosensory evoked potentials and brainstem auditory evoked potentials. DESIGN: Prospective, interventional study. SETTING: Intensive care unit of a university hospital. PATIENTS: A total of 32 adults with severe acute head trauma (Glasgow Coma Scale score < or = 8). METHODS AND MAIN RESULTS: In all patients, electroencephalographic recording was continuously performed by frontomastoid electrode montage for 24-96 hrs after admission to the ICU. The data were subsequently computed by fast Fourier analysis and the ESR (intervals of suppression as periods >240 msecs during which the electroencephalographic voltage did not exceed 5 microV) was displayed and recorded on a computer for further evaluation. Somatosensory evoked potentials and brainstem auditory evoked potentials were elicited during the first 2 days after admission. Outcome evaluation was performed 6 months after trauma using the Glasgow Outcome Scale and the Rappaport Disability Rating Scale. After careful artifact exclusion, the ESR depicted the highest sensitivity, specificity, and positive predictive value compared with evoked potentials. Even a highly significant correlation between outcome and ESR was found (p < .0001). CONCLUSION: The ESR is a valuable variable showing a high reliability with respect to outcome prediction in severe head trauma with a higher predictive value than short latency somatosensory evoked potentials. Evidence exists that the ESR provides at least partial information regarding adequate cerebral oxygen delivery.

Activities of Daily Living↗
PubMed1999

Comparison of radiography, scintigraphy and ultrasonography in the diagnosis of a case of temporomandibular joint arthropathy in a horse.

Diagnosis of temporomandibular joint disease in the horse presents a challenge to the equine veterinarian. This case report illustrates a combined imaging approach using radiography, scintigraphy and ultrasonography in a horse with severe arthropathy of the left temporomandibular joint. Radiographs were inconclusive. Scintigraphy with Tc99m methylenediphosphonate localised, but failed to characterise the disease process; ultrasonography was the only imaging method which both localised and characterised the lesion. Ultrasonography proved to be a relatively cheap, technically easy to perform and non-invasive method for the assessment of the disease.

Animals↗
PubMed1999

A pharmacodynamic and pharmacokinetic study with vedaprofen in an equine model of acute nonimmune inflammation.

The pharmacodynamics and enantioselective pharmacokinetics of vedaprofen were studied in six ponies in a two period cross-over study, in which a mild acute inflammatory reaction was induced by carrageenan soaked sponges implanted subcutaneously in the neck. Vedaprofen, administered intravenously at a dosage of 1 mg/kg, produced significant and prolonged inhibition of ex vivo serum thromboxane B2 (TXB2) synthesis and short-lived inhibition of exudate prostaglandin E2 (PGE2) and TXB2 synthesis. Vedaprofen also partially inhibited oedematous swelling and leucocyte infiltration into exudate. Vedaprofen displayed enantioselective pharmacokinetics, plasma concentrations of the R(-) enantiomer exceeding those of S(+) vedaprofen. The plasma concentration ratio, R:S, increased from 69:31 at 5 min to 96:4 at 3 h and plasma mean AUC values were 7524 and 1639 ng x h/mL, respectively. Volume of distribution was greater for S(+) vedaprofen, whilst elimination half-life (t(1/2beta)) and mean residence time were greater for R(-) vedaprofen. The penetration of vedaprofen into inflammatory exudate was also enantioselective. For R(-) and S(+) vedaprofen maximum concentration (Cmax) values were 2950 and 1534 ng/mL, respectively, and corresponding AUC values were 9755 and 4400 ng x h/mL. Vedaprofen was highly protein bound (greater than 99%) in both plasma and exudate. The significance of these data for the therapeutic use of vedaprofen is discussed.

Animals↗
PubMed1999

Endoscopic examination of the tarsal sheath of the lateral digital flexor tendon in horses.

This study was designed to develop a reliable technique for endoscopic examination of the tarsal sheath of the lateral digital flexor tendon of horses. The anatomy of the tendon sheath and associated structures was studied in detail in cadavers before determining portals for the insertion of an arthroscope into the sheath. Approaches into the sheath through the proximal pouch and through the flexor retinaculum, at the level of the sustentaculum tali, were performed and compared in cadavers. The proximal pouch portal permitted visualisation only of the proximal half of the sheath, while the approach through the retinaculum allowed examination of the entire sheath. The normal endoscopic appearance of the tarsal sheath was studied. The endoscopic approach was subsequently used to examine and treat 5 horses with tarsal sheath tenosynovitis, including 2 cases of chronic, traumatic tenosynovitis and 3 of subacute septic tenosynovitis. Four of these horses had fragmentation of the sustentaculum tali. The technique allowed adequate examination of the sheath and debridement of adhesions and lesions within the lumen of the sheath. Fragments dorsal to the medioplantar edge of the sustentaculum tali could not be visualised endoscopically and had to be removed after widening of the wound. All 5 horses survived. Follow-up enquiries (8-31 months) revealed that the horses were all reported to be sound. Four were performing at their previous level of activity, 1 was used for hacking. The 2 cases presented with chronic tenosynovitis had residual sheath distension with no associated loss of function. A prospective study, including longer term follow-up investigation, is currently being performed.

Animals↗
PubMed1999

Radiological study to evaluate suspected scapulohumeral joint dysplasia in Shetland ponies.

A radiological study was performed to test the hypothesis that osteoarthritis of the scapulohumeral joint in Shetland ponies is secondary to shoulder dysplasia. Animals were selected into 3 groups: Group 1: Shetland ponies with a radiological and clinical diagnosis of scapulohumeral osteoarthritis (n = 8); Group 2: Shetland ponies without forelimb lameness (n = 12); Group 3: Horses/ponies without a history or clinical signs of forelimb lameness (n = 22). Anatomical indices were measured from mediolateral radiographs of a scapulohumeral joint from each animal. There was a significant difference in the mean radius of curvature of the glenoid cavity of the scapula (RCG) between the 3 groups (MANOVA test, P = 0.003). The mean RCG of both Group 1 (P = 0.001) and Group 2 (P = 0.022) was significantly greater than that of Group 3. There was no significant effect of group on the radius of curvature of the humeral head or on the Conformity Index. There was a significant effect of group on the Glenoid Ratio (MANOVA test, P = 3 x 10(-6)). The mean Glenoid Ratio was significantly lower in both Group 1 (P = 2 x 10(-6)) and in Group 2 (P = 0.006) than in Group 3. These results indicate that the glenoid cavity of the scapula is 'flatter' and 'shallower' in Shetland ponies which we postulate to be a primary dysplasia in this breed.

Animals↗