bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein tyrosine phosphorylation in equine platelets: the effect of stimulation by thrombin and platelet‐activating factor (PAF)
Authors: DILLON ANNE M. R. , HEATH M. F. 
Published: April 2010

SummaryProtein tyrosine phosphorylation (PTP) in thrombin‐ and platelet‐activating factor (PAF)‐ stimulated equine platelet activation was investigated in the absence and presence of 2 protein tyrosine kinase inhibitors (PTKIs), methyl 2,5‐dihydroxyciimamate (MDHC) and genistein.Washed equine platelets aggregated irreversibly in response to thrombin or PAF in an agonist concentration dependent fashion. MDHC produced an MDHC concentration and time dependent inhibitory effect on rate and extent of thrombin‐ and PAF‐ induced aggregations, whereas the effect of genistein on the same parameters was only genistein concentration dependent.Western blotting demonstrated tyrosine phosphorylated proteins in resting platelets. Changes in the PTP pattern occurred both when platelets were stimulated with varying concentrations of thrombin or PAF for a standard time (3 min) or with a standard agonist concentration (0.17 u/ml thrombin or 10−10mol/l PAF) for varying times. Different patterns of PTP were produced by thrombin and PAF. 500 μmol/l MDHC and 300 μmol/l genistein each affected the PTP patterns produced in response to thrombin or PAF, but in different ways. PTP results with thrombin and PAF in the presence of 500 μmol/l MDHC were similar, as were those in the presence of 300 μmol/l genistein. However, there were many differences in the PTP results between thrombin (or PAF) in the presence of MDHC and between thrombin (or PAF) in the presence of genistein. Therefore, although both inhibitors are PTKIs, they have different effects on the PTP induced by either agonist. Our work has produced the first evidence of PTP in equine platelets. It is probable that the changes in PTP are related to events in the signal transduction pathway.
Factors affecting motion characteristics of frozen‐thawed stallion spermatozoa
Authors: HEITLAND A. V. , JASKO D. J. , SQUIRES E. L. , GRAHAM J. K. , PICKETT B. W. , HAMILTON C. 
Published: April 2010

SummaryFive experiments were conducted to evaluate damage incurred in each processing step for cryopreservation of stallion spermatozoa. In Experiment 1, semen was centrifuged for 9 centrifugation times and the percentage of spermatozoa recovered after each treatment was calculated and spermatozoal motion characteristics analysed. Recovery of spermatozoa was ≥80% when spermatozoa were centrifuged for ≥10 min. Experiment 2 evaluated spermatozoa cryopreserved at 5 different concentrations in each of 2 extenders (skim milk‐egg yolk‐glycerol, SM‐EYG; and lactose‐EDTA, LAC). In SM‐EYG, TMOT and PMOT were higher at spermatozoal concentrations of 20, 200 and 400 times 106/ml (51%/41%, 52%/44%, 50%/43%, respectively) than for samples frozen at ≥800 times 106 spermatozoa/ml (41%/35%, 32%/27%; P<0.05). Spermatozoa frozen in LAC at a concentration of 20 times 106/ml resulted in the highest TMOT and PMOT (43% and 30%, respectively, P<0.05). The effect of freezing rate on motion characteristics of spermatozoa was evaluated in Experiment 3. The VCL of spermatozoa frozen in SM‐EYG was the only parameter affected by freezing rate (P<0.05). Experiment 4 evaluated motion characteristics after cryopreservation of spermatozoa in different sized straws (0.5 or 2.5 ml) in each of 2 extenders (SM‐EYG and LAC). In SM‐EYG, PMOT (38%) and VCL (109 μm/s) were highest when spermatozoa were frozen in 0.5 ml straws (P<0.05). In Experiment 5, spermatozoa thawed immediately after cryopreservation or thawed after storage in liquid nitrogen for 24–48 h were evaluated. There was no effect of length of storage in liquid nitrogen on spermatozoal motion characteristics (P<0.05). Experiment 6 evaluated the effects of cooling time to 5°C (0, 2.5 and 5 h) on motion characteristics of spermatozoa cryopreserved in 2 extenders (SM‐EYG and LAC). TMOT and PMOT were effected by cooling time, and there was a cooling‐time‐by‐extender interaction (P<0.05). In SM‐EYG, TMOT and PMOT were higher if spermatozoa were cooled to 5°C prior to initiation of freezing than if freezing was initiated at 20°C (P<0.05).A suggested protocol for cryopreservation of stallion spermatozoa would include: 1) centrifugation at 400 g for 14 to 16 min; 2) extension at 23°C with SM‐EYG to 400 times 106 spermatozoa/ml; 3) cool to 5°C for 2.5 h; 4) package in 0.5 ml straws at 5°C; 5) freeze in liquid nitrogen vapour at −160°C; and 6) thaw for 30 s in 37°C water.
Limb movement adaptations in horses with experimentally induced fore‐ or hindlimb lameness
Authors: BUCHNER H. H. F. , SAVELBERG H. H. C. M. , SCHAMHARDT H. C. , BARNEVELD A. 
Published: April 2010

SummaryThe kinematic patterns of all limbs of 11 clinically nonlame Dutch Warmblood horses were studied during induced supporting limb lameness to gain insight into the compensation mechanisms horses use to manage lameness and to test kinematic limb variables for their significance as lameness indicators. Using the locomotion analysis system CODA‐3, the kinematics of the horses were recorded while walking (1.6 m/s) and trotting (3.5 m/s) on a treadmill. A transient lameness model, evoking pressure on the hoof sole, was used to induce 3 degrees of fore‐ and hindlimb lameness. Joint angle patterns and hoof movements were analysed using joint angle/time diagrams and the hoof trajectories in the sagittal plane. Quantitative analysis of 13 selected variables in each limb was done using a 2‐way analysis of variance.Hyperextension of the fetlock joint and flexion of the coffin joint during the stance phase decreased significantly (P<0.05) in the lame limb, both in fore‐ and hindlimb lameness, at both gaits. In the contralateral nonlame limbs, both variables increased compensatorily. Flexion increased with increasing lameness in the proximal joints, i.e. the shoulder joint and even more the tarsal joint of the lame limb. The retraction of both forelimbs decreased during forelimb lameness at the walk, while in the lame hindlimb the protraction decreased. The hoof arcs were lower in the lame limb than in the nonlame limb, due to an increased hoof height in the nonlame limb during forelimb lameness and to a decreased height in the lame limb during hindlimb lameness.It was concluded that patterns of the distal joints reflect the different loadings of the limbs during lameness. Proximal joints acted as load dampers to reduce peak forces in the lame limb. Hyperextension of the fetlock and flexion of the coffin joint proved to be the most sensitive indicators for fore‐ and hindlimb lameness.
Head and trunk movement adaptations in horses with experimentally induced fore‐ or hindlimb lameness
Authors: BUCHNER H. H. F. , SAVELBERG H. H. C.M. , SCHAMHARDT H. C. , BARNEVELD A. 
Published: April 2010

SummaryThe kinematic patterns of head and trunk were studied in horses during induced supporting limb lameness to understand the mechanisms horses use to compensate for lameness and to evaluate different symmetry indices for their significance as lameness indicators. Using the locomotion analysis system CODA‐3 the kinematics of 11 clinically nonlame Dutch Warmblood horses were recorded while walking (1.6 m/s) and trotting (3.5 m/s) on a treadmill. A transient lameness model, evoking pressure induced pain on the hoof sole, was used to induce 3 degrees of fore‐ and hindlimb lameness. Peak vertical displacement, velocity and acceleration of head, withers,tuber sacraleand bothtuber coxaewere quantified at different phases of the stride. Changes in these variables due to lameness and symmetry indices calculated as quotients of the values during the lame and nonlame stance phase were analysed using a 2‐way analysis of variance.The head, withers andtuber sacraleshowed a similar sinusoidal pattern in their vertical displacement, velocity and acceleration. During both fore‐ and hindlimb lameness at the trot, the vertical velocity of the trunk at impact of the lame limb decreased (P<0.05), during the lame stance phase the trunk was kept higher above the ground, maximal acceleration decreased and displacement amplitude was smaller than without lameness. Changes in movements of the head were much more expressed than movements of the withers during forelimb lameness and reversed during hindlimb lameness. At the walk, head movement patterns changed in the same way as at the trot, while withers andtuber sacralepatterns were hardly changed. Symmetry indices of all landmarks showed changes due to increasing lameness at the trot. The maximal vertical acceleration of the head and displacement amplitude of thetuber sacraleproved to be the best indicators to quantify a fore‐ and hindlimb lameness, respectively.
Radiographic and arthroscopic findings associated with subchondral lucency of the distal radial carpal bone in 71 horses
Authors: DABAREINER R. M. , WHITE N. A. , SULLINS K. E. 
Published: April 2010

SummaryCase records and radiographs of 71 horses with subchondral lucency, without radiographic evidence of fracture, located on the distal radial carpal bone were examined retrospectively. All horses had lameness and/or joint effusion referable to the carpus. Distal radial carpal bone subchondral lucency was found as a solitary lesion or as a lesion concurrent and symmetric to a contralateral distal radial carpal bone chip fracture. The lesion appeared radiographically as a lucency or shadow on the distal dorsal margin of the radial carpal bone and was most evident on the flexed lateromedial and dorsolateral‐palmaromedial oblique projections. Sixty‐four joints in 55 horses underwent arthroscopic surgery. Surgical findings included osteochondral fragmentation in 44 joints, cartilage fragmentation with subchondral bone softening in 17 joints and cartilage fraying in 3 joints. Corresponding third carpal bone lesions were observed in 18 joints and moderate to severe synovitis was present in 24 joints. Carpal bone subchondral radiolucency without a fracture fragment observed on radiographs indicated cartilage and bone damage. In some cases, small chip fractures (1–2 mm) were present within the cartilage debris examined at surgery, yet were not radiographically visible. Follow‐up information was obtained on 50 of the operated horses and 14 nonoperated horses. Forty (80%) of the surgically treated horses returned to racing, with 34 (68%) of these horses (20 of 26 with subchondral lucency as a solitary lesion) racing at a level of competition equal to or better than the pre‐injury level. Of the 14 horses which were not operated, 6 (42%) returned to racing of which only 2 (14%) raced at the same pre‐injury level of competition. Radiographic evidence of radial or intermediate carpal bone subchondral lucency is an indication of cartilage and bone damage which is best treated with arthroscopic surgery.
Computed tomographic evaluation of head diseases in the horse: 15 cases
Authors: TIETJE S. , BECKER M. , BÖCKENHOFF G. 
Published: April 2010

SummaryThe rapid development of software and technology now allows a large amount of diagnostic information to be obtained from a computed tomographic examination. This imaging technique can also be usefully applied to the horse, given appropriate premises and a custom built table for accurate positioning. Computed tomography of the skull has considerable advantages over other techniques, as structures are viewed without superimposition. Fifteen cases are used to demonstrate how through high image quality (precise detail, reduction in artefacts) and objective measurement of density, various pathological changes can be analysed and exact diagnoses achieved. In particular, short measurement and examination times allow preoperative imaging under general anaesthesia giving significant information to assist subsequent surgery.
Effect of a warm‐up on energy supply during high intensity exercise in horses
Authors: Tyler Catherine M. , Hodgson D. R. , Rose R. J. 
Published: April 2010

SummaryThe V̇O2max in racehorses is approximately double that of elite human athletes and the rate of increase in V̇O2 at the onset of high intensity exercise is much greater than in man. The kinetics of gas exchange are affected by a warm‐up prior to exercise in humans, there being a greater aerobic contribution to high intensity exercise after warm‐up. Our hypothesis was that a warm‐up would increase aerobic energy delivery in racehorses during high intensity exercise. Thirteen fit Standardbred racehorses ran to fatigue at 115% of V̇O2max on a treadmill at 10% slope. Prior to acceleration, horses were exercised either for 5 min at 50%V̇O2max followed by 5 min walk, or walked for 2 min. Samples of expired gas were collected every 10 s during the run for determination of V̇O2 and V̇CO2 and measurement of maximal accumulated oxygen deficit (MAOD). Blood lactate concentration was measured 5 min post exercise. We found that with a warm‐up, horses had faster kinetics of gas exchange and a greater proportion of their total energy requirement was supplied by aerobic sources. The aerobic contribution to total energy requirement with and without warm‐up was, respectively, 79.3 ± 1.0% and 72.4 ± 1.7% (P<0.01). There was also a higher MAOD (P< 0.01) in horses that had not been given a warm‐up (mean ± s.e.m. 34.7 ± 2.6 and 47.3 ± 2.6 ml O2 eq/kg bwt with and without a warm‐up respectively). However, there were no significant differences in total run time or estimated total energy expenditure between the 2 protocols. We concluded that during high intensity exercise to fatigue lasting 1 to 2 min, more than 70% of energy supply is from aerobic energy sources and that this contribution is even greater when the horses have received a warm‐up.
Tendon strain in the forelimbs as a function of gait and ground characteristics andin vitrolimb loading in ponies
Authors: RIEMERSMA D. J. , VAN DEN BOGERT A. J. , JANSEN MARGOT O. , SCHAMHARDT H. C. 
Published: April 2010

SummaryStrains in the tendons of them. flexor digitalis superficialis(superficial digital flexor, SDFT) andm. flexor digitalis profundus(deep digital flexor, DDFT) tendons, the accessory ligament of the deep digital flexor muscle (inferior check ligament, ICL) and them. interosseus medius(suspensory ligament, SL) of 5 ponies were recorded at the walk and trot using mercury‐in‐silastic strain gauges (MISS), on a hard surface (brick pavement) and on sand. The horses were shod with normal, flat shoes.On pavement, strain in the SDFT, DDFT and SL increased significantly from the walk (2.19%, 1.15% and 3.36%, respectively) to the trot (4.15%, 1.70% and 5.78%, respectively), but that in the ICL did not change significantly (5.36% at the walk, 4.88% at the trot). Strains in the ICL and SL were higher on pavement than on sand (P<0.1) and strains in the SDFT and DDFT were not significantly different. Tendon strain in the SDFT and SL, but not in the ICL and DDFT, increased (P<0.1) in a pony at the walk on pavement with a rider.Post mortemloading of the same instrumented limbs revealed that the metacarpophalangeal joint could be further extended when the elbow joint was extended. Thein vitrotendon strain was different from thatin vivo, implying that results fromin vitrolimb loading tests have only limited value for assessing tendon functioningin vivo.
Equine herpesvirus type 2: prevalence and seroepidemiology in foals
Authors: MURRAY M. J. , EICHORN EVELYN S. , DUBOVI E. J. , LEY W. B. , CAVEY D. M. 
Published: April 2010

SummaryWhole blood and serum were collected from foals to determine the prevalence of Equine herpesvirus type 2 (EHV2) infection in foals, age at which infection can first be identified and serological responses to infection. Equine herpesvirus type 2 was isolated from peripheral blood mononuclear cells (PBMC) from 68 of 69 foals, 1–8‐months‐old, sampled once. Virus isolation was performed twice at intervals of 2–7 months on PBMCs from 33 foals and EHV2 was isolated on both occasions in all but one foal (negative, then positive). Regression analysis of log2‐transformed reciprocal serum EHV2 virus neutralising (VN) titres revealed that in foals age 1–7 months, EHV2 VN antibody titre was positively correlated with age (r = 0.94). Paired serum samples were obtained from 58 foals, with the first samples collected age 1–6 months and the second samples collected 2–4 months later. There were significant (P<0.05) increases in mean VN titres to EHV2 in foals sampled initially at age 1–4.Eight foals had blood sampled prior to sucking and at age 7, 20, 30 and 45 days. Each foal was negative for EHV2 in PBMC and each foal had a negative serum EHV2 VN titre immediately after birth. Each foal was positive for EHV2 in PBMC by age 45 days, with the earliest isolation at 25 days.Tracheal aspirate fluid and peripheral blood were collected from 20 foals without clinical signs of respiratory disease and from 30 foals with clinical signs of lower respiratory disease. In 20 foals without clinical signs of respiratory disease, EHV2 was isolated from tracheal aspirates (1/20 foals) and PBMC (20/20 foals) and in 30 foals with such clinical signs, from trachea aspirates (20/30 foals: P<0.01) and from PBMC (30/30 foals). In one 6‐month‐old foal, EHV1, but not EHV2, was isolated from the tracheal aspirate, 3 months after EHV2 had been isolated from a tracheal aspirate. These results demonstrate a greater prevalence of EHV2 in lower respiratory secretions in foals with clinically apparent lower respiratory disease, but a cause and effect relationship between the virus and lower respiratory disease remains to be elucidated. It is noteworthy, however, that of virus isolations performed on 50 tracheal aspirates, a virus (EHV1) other than EHV2 was isolated only once.
Histomorphological endometrial status and influence of oxytocin on the uterine drainage and pregnancy rate in mares
Authors: RASCH KATHRIN , SCHOON H. A. , SIEME H. , KLUG E. 
Published: April 2010

SummaryThe aim of this field study was to examine the influence of the uterotonic substance oxytocin in 2 different therapeutic dosages of 15 and 25 iu, respectively on the uterine drainage of oestrous mares and on their fertility. In addition endometrial biopsies of mares with and without intrauterine fluid accumulations around the time of ovulation were evaluated histomorphologically regarding the aetiology of susceptibility to uterine infection.A population of 59 Hanoverian Warmblood mares was used in this study. The mares were divided intoGroup A(mares with intrauterine fluid accumulations [n = 49]) andGroup B(controls [n = 10]).Group Awas further subdivided into 3 groups according to varying oxytocin administrations (none, 15 iu, 25 iu). Prior to insemination, all mares were examined by rectal palpation, ultrasonography and vaginal inspection.In addition, hormone plasma concentrations were evaluated at the time of ovulation, namely oestradiol and progesterone concentrations. Endometrial biopsies were obtained from all mares. Endometrial samples for microbiological and cytological evaluation were taken from mares ofGroup Aonly. All mares were inseminated close to ovulation during the first cycle.This study shows that intravenous oxytocin treatment of mares with intrauterine fluid accumulations results in better pregnancy rates than no treatment.
Effects of flunixin, tolfenamic acid, R(−) and S(+) ketoprofen on the response of equine synoviocytes to lipopolysaccharide stimulation
Authors: LANDONI M. F. , FOOT R. , FREAN S. , LEES P. 
Published: April 2010

SummaryThe objective of this study was to analyse the effects of 4 nonsteroidal anti‐inflammatory drugs (NSAIDs) on the production of β‐glucuronidase (β‐glu), tumour necrosis factor alpha (TNFα), interleukin‐6 (IL‐6), interleukin‐1 (IL‐1) and prostaglandin E2(PGE2) by lipopolysaccharide (LPS)‐stimulated equine synoviocytes. The agents studied were flunixin, tolfenamic acid, S(+)ketoprofen (KTP) and R(‐)ketoprofen.LPS‐induced release of β‐glu from synoviocytes was inhibited in a concentration dependent manner by all 4 compounds, tolfenamic acid being the most potent. Of the 2 KTP enantiomers, S(+)KTP exerted the greatest inhibitory effect. Tolfenamic acid and flunixin increased the production of IL‐6‐like activity by LPS‐stimulated synoviocytes only at the highest concentration studied (1000 μmol/l). Lower concentrations produced no effect on IL‐6. Flunixin, tolfenamic acid and S(+)KTP produced statistically significant and concentration related increases in the release of IL‐1‐like activity by LPS‐stimulated synoviocytes. Prostaglandin E2synthesis was markedly inhibited in a concentration dependent manner by the 4 NSAIDs. However, R(‐)KTP was effective only at the highest concentrations investigated (1000 and 100 μmol/l).The present findings are compatible with the possibility that longterm use of NSAIDs in arthropathies, by removing the regulator role of PGE2on IL‐1 synthesis, might enhance the pathological process of cartilage degeneration.
Pharmacokinetics of ceftriaxone in healthy horses
Authors: RINGGER N. C. , PEARSON E. G. , GRONWALL R. , KOHLEPP S. J. 
Published: April 2010

SummaryFive healthy Equidae (4 horses and one pony) were given a single i.v. dose of ceftriaxone (50 mg/kg bwt) to determine the pharmacokinetics and concentration in cerebrospinal fluid (CSF). Blood was drawn from an i.v. jugular catheter and CSF from a pre‐placed, intrathecal catheter. Serum and CSF concentrations were determined by high performance liquid chromatography. The mean serum concentration of ceftriaxone was 144.7 μg/ml 15 min after injection and declined to 0.3 μg/ml 10 h after injection. The elimination rate constant (Λ2) was 0.63 ± s.e. 0.23/h, the elimination half‐life (t1/2) was 1.62 ± s.e. 0.42 h apparent volume of distribution at steady state (Vd(ss)) was 330.8 ± 11.8 ml/kg bwt. Clearance was 312.7 ± 38 ml/h/kg bwt and mean residence time was 1.13 ± 0.14 h. Mean CSF concentration was 0.60 ± 0.14 μg/ml at 3 h after injection and 0.4 ± 0.31 μg/ml at 8 h. Ceftriaxone may be useful in the treatment of bacterial infections in horses. Its ability to penetrate the CSF should make it effective in the treatment of bacterial meningitis.
Kinematics of the distal hindlimb during stance phase in the fast trotting Standardbred
Authors: JOHNSTON C. , ROEPSTORFF L. , DREVEMO S. , KALLINGS R. 
Published: April 2010

SummaryFast trotting Standardbred horses were filmed along a straight on an oval dirt track. Five consecutive stance phases were analysed to describe the planar kinematics of the distal hindlimb. The rapid changes in the geometry of the distal hindlimb that occur during the early stance phase were studied. The hoof segment was initially braked vertically and moved in the direction of the horse. The hoof moved forward on the track surface for more than 20% of the stance time (ST). Two specific deviations in the otherwise smooth course of the fetlock joint angle appeared at 16 and 29% of ST. Tarsal angular joint displacement was, on the other hand, more smooth throughout the stance phase. Segment angular velocity was greatest in the proximal pastern segment, while the metatarsus was almost totally braked in its forward rotation during the early stance. Tibial angular velocity was more smooth and greater than that of the metatarsus. Initial vertical braking of the hoof was related to the rapid rotation of the proximal pastern segment, while the metatarsal and proximal pastern segment angular velocities decreased as the hoof was braked horizontally. Also coincident with horizontal braking of the hoof was an increase in the angular velocity of the tibial segment.It was concluded that the horizontal as well as the vertical braking of the hoof affect the disto‐proximal braking of the segments of the distal hindlimb during the early stance phase. The early stance phase changes in the distal hindlimb suggest rapid changes in the internal forces of the limb and should be of importance to the orthopaedic health of Standardbred trotters. These rapid changes at the fetlock joint and hock joint during the early stance may be important in lameness as excessive rapid and repetitive loading and movement are thought to induce joint damage (Radin et al. 1991).