bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spasmogenic action of endothelin‐1 on isolated equine pulmonary artery and bronchus
Authors: BENAMOU A. E. M. , MARLIN D. J. , CALLINGHAM B. C. , HILEY R. C. , LEKEUX P. 
Published: April 2007

SummaryReasons for performing study: There is currently little published information about the effects of endothelin‐1 (ET‐1), a potent endogenous spasmogen of vascular and airway smooth muscle, on pulmonary vasculature and airways or which ET receptor subtypes mediate ET‐1‐induced vasoconstrictive and bronchoconstrictive action in the horse.Objectives: To investigate the effect of endothelin‐1 (ET‐1) on smooth muscle from isolated equine pulmonary artery and bronchus. In addition, the roles of ETAand ETBreceptors in ET‐1 mediated contraction in these tissues were assessed.Methods: The force generation of ring segments from pulmonary arteries or third‐generation airways (obtained from horses subjected to euthanasia fororthopaedic reasons) were studied in an organ bath at 37°C in response to exogenous endothelin and selective endothelin A (BQ123) or B receptor (BQ788) antagonists.Results: ET‐1 produced concentration‐dependent contractions of the equine pulmonary artery and bronchus. The threshold for contraction was 10−10and 10−9mol/l ET‐1 for pulmonary artery and bronchus, respectively. The maximal contraction induced by the highest ET‐1 concentration (10−7mol/l) was 173 and 194% of the contraction obtained with 100 mmol/l KCl in pulmonary artery and bronchus, respectively. ET‐1 potency was 25 times greater in equine pulmonary artery than in equine bronchus (concentration of ET‐1 producing 50% of maximal contraction [EC50] = 5.6 10−9mol/l and 2.2 10−8mol/l, respectively). In pulmonary artery, ET‐1 induced contractions were significantly inhibited by the ETAreceptor antagonist BQ123 (1 μmol/l; dose‐response curve to ET‐1 was shifted to the right by 5.4‐fold), but not by the ETBantagonist BQ788. In bronchus, dose‐responses curves to ET‐1 were shifted to the right by BQ123 (1 μmol/l; 2.5‐fold), but not by BQ788 (1 μmol/l). In the presence of both antagonists, the dose‐response curve to ET‐1 was shifted to the right by 4.5‐fold.Conclusions: These functional studies demonstrate that ET‐1 is a potent spasmogen of equine third generation pulmonary artery and bronchus, and that contractions are mediated via ETAreceptors in the former and both ETAand ETBreceptors in the latter.Potential clinical relevance: Endothelin receptor antagonists may have potential for treating equine pulmonary hypertension or bronchoconstriction.
Investigations into the role of the thyrohyoid muscles in the pathogenesis of dorsal displacement of the soft palate in horses
Authors: DUCHARME N. G. , HACKETT R. P. , WOODIE J. B. , DYKES N. , ERB H. N. , MITCHELL L. M. , SODERHOLM L. V. 
Published: April 2007

SummaryReasons for performing study: Contributes to the understanding of the pathogenesis of dorsal displacement of the soft palate during exercise so that management of this condition could be enhanced.Hypothesis: That the thyrohyoid muscles play an important role in the stability of the laryngo‐palatal relationship and that dysfunction of these muscles leads to dorsal displacement of the soft palate (DDSP) during exercise.Methods: Ten horses were exercised on a high‐speed treadmill under 4 different treatment conditions: control conditions (n = 10), after resection of thyrohyoid muscles (TH, n = 10), after sham‐treatment (n = 5), or after restoration of function of the thyrohyoid muscles with surgical sutures (prosthesis‐treatment, n = 6). During trials, the following determinations were made: videoendoscopy of the upper airway, gait frequency and pharyngeal and tracheal static pressures.Results: None of the 10 horses developed DDSP during 2 separate treadmill‐exercise trials under the control conditions. Seven of the 10 horses developed DDSP after resection of the TH muscles, 4 of 5 of these horses still experienced DDSP aftersham‐treatment, but 5 of 6 horses no longer experienced DDSP at exercise after the prosthesis‐treatment. There were significant anomalies in airway pressures, respiratory frequency, and occurrence of DDSP in both the TH resection and sham‐treatment conditions compared to control conditions. In contrast, no statistical differences were noted in any of the parameters measured between the prosthesis‐treatment and control conditions.Conclusions: That the function of the TH muscles is important to the stability of the laryngo‐palatal relationship and plays a role in the pathophysiology of exercise‐induced DDSP.Potential relevance: Management of horses with DDSP could be enhanced by restoring the function of the TH muscles.
The sacroiliac joints: evaluation using nuclear scintigraphy. Part 1: The normal horse
Authors: DYSON S. , MURRAY R. , BRANCH M. , WHITTON C. , DONOVAN T. , HARDING E. 
Published: April 2007

Summary Reasons for performing study: Sacroiliac (SI) disease is recognised as a cause of poorhindlimb action but differential diagnosis is often difficult. Hypotheses: That in clinically normal horses there would be a significant difference in the ratio of radiopharmaceutical uptake (RU) between the fifth lumbar vertebra (L5) and each tuber sacrale (TS) and between L5 and each SI joint; and that these ratios would alter with age, but ratios would be bilaterally symmetrical. Methods: Dorsal scintigraphic images of the SI region of 15 horses, selected randomly from the clinic database, were analysed by 2 of the authors, comparing noncorrected and motion‐corrected images. To determine scintigraphic anatomy, the scintigraphic images of 10 Thoroughbred horses were superimposed over a ventrodorsal radiographic image of an isolated pelvis.Dorsal scintigraphic images of 40 clinically normal horses age 3–16 years were evaluated using subjective examination, profile analysis and quantification using regions of interest. Results: The tubera sacrale were seen as 2 well‐defined oval regions immediately to the left and right of the midline, abaxial to which were larger, approximately oval areas with less RU, representing uptake in the SI joints. The definition between the SI region and the TS was more obvious in younger horses. Nonmotion‐corrected images were often not of diagnostic quality or could be misinterpreted as abnormal. There were significant differences in RU between the TS and SI joints compared to L5, and decreased RU in the tubera sacrale with increasing age, but no change of uptake in the SI joint region and no effect of gender on RU. There was a high degree of left‐right symmetry of the TS and SI joint regions. Conclusions and potential relevance: The scintigraphic images of horses with suspected sacroiliac joint disease should be compared with images of normal horses of comparable age. In normal horses, there was a high degree of symmetry; therefore, marked left‐right asymmetry is likely to be abnormal.
Validation and clinical utility of a novel immunoradiometric assay exclusively for biologically active whole parathyroid hormone in the horse
Authors: ESTEPA J. C. , GARFIA B. , GAO P. , CANTOR T. , RODRIGUEZ M. , AGUILERA‐TEJERO E. 
Published: April 2007

SummaryReasons for performing study: Parathyroid hormone (PTH) plays a critical role in the regulation of mineral metabolism in mammals. Until recently, the standard method for PTH measurement has been the 2nd generation intact‐PTH (I‐PTH) assay. Current evidence indicates that the I‐PTH assay binds to the PTH molecule and to an inactive N‐terminally truncated PTH fragment that tends to accumulate in the blood of uraemic patients. Therefore, a new 3rd generation PTH assay that detects only the whole PTH molecule (W‐PTH; cyclase‐activating PTH [CAP]) has been developed.Objectives: To validate this more specific W‐PTH assay for measurement of equine PTH and evaluate its clinical utility.Methods: W‐PTH and I‐PTH were measured in plasma samples from normal horses (adults and foals) and horses with nutritional secondary hyperparathyroidism (N2HPT) and with chronic renal failure (CRF). Replicate measurements and dilutional paralellism were used for assay validation. Changes in blood ionized calcium were induced by EDTA and CaCl2administration.Results: Performance of the W‐PTH assay (accuracy, sensitivity, specificity and ability to detect changes in PTH in response to changes in calcium) was similar to that of the I‐PTH assay. Surprisingly, the relative W‐PTH concentration in normal horses and foals was higher than the relative I‐PTH concentration. W‐PTH values remained higher than I‐PTH during acute hypo‐ and hypercalcaemia. An increase in both W‐PTH and I‐PTH concentrations was found in horses with N2HPT. In horses with CRF, W‐PTH and I‐PTH values were very low and no increase in I‐PTH was observed.Conclusions: The W‐PTH assay can be used for measurement of equine PTH.Potential relevance: The use of W‐PTH assay is likely to improve the diagnosis of mineral metabolism in horses.
The sacroiliac joints: evaluation using nuclear scintigraphy. Part 2: Lame horses
Authors: DYSON S. , MURRAY R. , BRANCH M. , HARDING E. 
Published: April 2007

Summary Reasons for performing study: Sacroiliac (SI) joint disease is difficult to diagnose definitively on clinical grounds. Hypotheses: Lameness not attributable to SI joint pain may result in asymmetrical uptake of radiopharmaceutical in the tubera sacrale and SI joints; and that horses with clinical signs suggestive of sacroiliac joint disease would have differences in the ratios of radiopharmaceutical uptake between the fifth lumbarvertebra (L5) and either the tubera sacrale or SI joints compared with normal horses. Objectives: To determine whether differences in radiopharmaceutical activity could identify individuals with presumed SI joint region pain. Methods: The scintigraphic appearance of the pelvic region of 234 horses (Group I) with lameness unrelated to the SI joints was compared with that for 40 normal horses (Group N) in full work and that for 41 horses with suspected SI joint disease (Group II). The effect of age, sex, lame limb and discipline were assessed in Group I.Motion‐corrected scintigraphic images were assessed grossly, using profile analysis and by comparing ratios of uptake of mean count per pixel between L5 and each of the left (L) tuber sacrale (TS), right (R) TS, LSI and RSI joints. Left‐right symmetry was compared. Results: Lame horses (Group I) had greater asymmetry of radiopharmaceutical uptake in the tubera sacrale compared with normal horses. Horses with right hindlimb lameness had a larger RSI/LSI ratio compared to normal horses. In Group I L5/LTS, L5/RTS and L5/RSI increased with age, and there was a trend for L5/LSI to increase with age.In horses with presumed sacroiliac joint disease (Group II), L5/LTS, L5/RTS and L5/RSI were all greater compared with normal horses. Detection of marked left‐right asymmetry by quantitative analysis or profile analysis was helpful in discriminating between those horses with clinical signs compatible with SI joint disease and either normal horses or those lame due to another cause. Conclusions and potential relevance: Scintigraphic evaluation of the SI region is useful to identify SI joint disease in combination with other clinical signs supportive of the diagnosis. However, diagnosis should not be based on this alone because of some degree of overlap in the range of radiopharmaceutical uptake between horses with SI joint disease and both normal horses and those with other causes of lameness.
Mucin genes in horse airways: MUC5AC, but not MUC2, may play a role in recurrent airway obstruction
Authors: GERBER V. , ROBINSON N. E. , VENTA P. J. , RAWSON J. , JEFCOAT A. M. , HOTCHKISS J. A. 
Published: April 2007

Summary Reasons for performing study: Increased mucin gene expression may be an important cause of mucus accumulation observed in recurrent airway obstruction (RAO)‐affected horses. To date, however, no mucin gene sequences are available for the horse. Objectives: To identify equine homologues of gel‐forming mucins and investigate their expression at different airway generations of healthy and RAO‐affected horses. Methods: Two equine homologues were identified by cloning and sequencing fragments of equine (eq)MUC5AC and eqMUC2. Results: Semiquantitative RT‐PCR on RNA from airways (generations 1, 5, 10, 15; small airways and parenchyma), stomach (glandular), and colon revealed that eqMUC5AC is expressed in equine stomach and in all of the airway samples. In contrast, eqMUC2 steady‐state mRNA levels were detected in colon and very faintly in stomach, but not in airway tissue. EqMUC5AC expression was also compared to that of ZO‐1, a tight junction protein, and eqMUC5AC/ZO‐1 ratios were higher in RAO‐affected compared to control horses at all airway generations. Conclusions: That eqMUC5AC is expressed in horse airways, but any expression of MUC2 is undetectable and unlikely to be of physiological consequence. Potential relevance: EqMUC5AC up‐regulation may be a primary mechanism responsible for mucus hypersecretion and accumulation in RAO.
Idiopathic mucosal lesions of the arytenoid cartilages of 21 Thoroughbred yearlings: 1997–2001
Authors: KELLY G. , LUMSDEN J. M. , DUNKERLY G. , WILLIAMS T. , HUTCHINS D. R. 
Published: April 2007

Summary Reasons for performing study: Mucosal ulcers and, occasionally, small granulomas on the axial surface of one or both arytenoid cartilages have been found in TB yearlings presented for post sale endoscopic examination. Objectives: To determine the incidence, endoscopic characteristics and outcome of a group of Thoroughbred yearlings affected with mucosal ulcers and granulomas of the arytenoid cartilage. Hypothesis: The incidence of mucosal ulceration of the arytenoid cartilages of yearling Thoroughbreds is relatively high compared to other upper airway abnormalities; and that the majority of mucosal ulcers heal uneventfully, although a small percentage may progress to a granuloma and, less commonly, to arytenoid chondropathy. Methods: The findings of post sale, upper airway endoscopic examinations of 3312 Thoroughbred yearlings, during a 5 year period, were reviewed, including those abnormalities listed in the conditions of sale and others not listed but considered likely to cause airway obstruction. Information obtained from the medical record of horses that had mucosal ulceration or granuloma of the arytenoid cartilage included the location and size of the lesion(s), sex of the affected horse and the presence and nature of other concurrent abnormalities of the upper portion of the respiratory tract. Additional information included treatment and results of follow‐up, endoscopic examination by the authors or attending veterinarian. Results: Mucosal lesions were seen in 0.63% of yearlings evaluated, which represented the most common, documented condition of the upper portion of the respiratory tract. The mucosal ulcers of 15 of 19 horses were considered to have healed without complication during follow‐up examination; one of the 19 horses was lost to follow‐up. Two horses affected with bilateral, arytenoid mucosal ulceration developed a granuloma at each site of ulceration. One horse developed a granuloma at a site of ulceration and, subsequently, arytenoid chondropathy. Conclusions: Arytenoid mucosal ulceration in sales yearlings was a relatively commonly encountered abnormality and a small percentage progressed to granuloma or chondropathy. Potential relevance: The mucosa of the arytenoid cartilage, particularly at the rostral margin of the vocal process, should be examined carefully during endoscopic examination of the upper portion of the respiratory tract of Thoroughbred yearlings presented for sale. Because a small percentage of mucosal ulcers may progress to granuloma or, less commonly, chondropathy, identification of mucosal ulcers of the arytenoid cartilage seen during post sale, endoscopic examination warrants notification to the purchaser and sales company. Medical therapy of affected horses should be considered and follow‐up endoscopic examination performed to determine if the lesion has healed.
Verification of skin‐based markers for 3‐dimensional kinematic analysis of the equine tarsal joint
Authors: KHUMSAP S. , LANOVAZ J. L. , CLAYTON H. M. 
Published: April 2007

SummaryReasons for performing study: Kinematic studies are usually based on tracking markers attached to the skin. However, complex joints, such as the tarsal joint, function in 3‐dimensions (3D), and have therefore necessitated application of the invasive bone pin technique, limiting kinematic studies to the research laboratory. This study investigates the feasibility of using skin‐based markers for 3D analysis of tarsal joint motion.Hypothesis: Three‐dimensional motions of the tarsal joint can be measured with an acceptable degree of accuracy using skin markers.Methods: Retroreflective markers were attached over the tibial and metatarsal segments. Markers were tracked automatically at trot. Three‐dimensional skin correction algorithms were used for correction of skin displacement, and 3D motions derived from the corrected (CSD) and uncorrected (USD) skin displacement were compared with data from a previous study in which those motions were described using bone‐fixed markers (BFM) by correlation, root mean square errors (RMS) and shape agreement (SA) of the curves.Results: The RMS of BFM and CSD were smaller than those of BFM and USD for all motions. The correlation coefficients of BFM and CSD were higher than those of BFM and USD. SA was good or fair for all motions except internal/external rotation and medial/lateral translation.Conclusions and potential relevance: With appropriate correction for skin movement relative to skeletal landmarks, skin markers can identify tarsal 3D motions for flexion/extension, abduction/adduction, cranial/caudal translation, and proximal/distal translation, allowing analysis and comparison of information between horses during swing and stance phases.
Dynamic pressure measurements for the detailed study of hoof balance: the effect of trimming
Authors: VAN HEEL M. C. V. , BARNEVELD A. , VAN WEEREN P. R. , BACK W. 
Published: April 2007

SummaryReasons for performing study: Studies on hoof balance have, so far, only assessed the effects of strong and relatively unrealistic interventions due to technical limitations of measuring equipment. For the assessment of more subtle interventions, other techniques are necessary.Objectives: To test a sensitive pressure measurement system during locomotion and to set a standard for further studies by using the system to evaluate the effects of trimming.Methods: Eighteen horses were measured before and after trimming with an interval of 4 weeks. Trimming was standardised to a straight hoof‐pastern axis. The horses trotted over a pressure/force measuring system, with a temporal resolution of 240 Hz and a spatial resolution of 0.39 cm2.Results: The preferred way of landing was lateral, asymmetrical in both front and hind feet. The duration of landing was shorter in forelimbs than in hindlimbs with an equal decreasing trimming effect. Horses had a fixed hoof‐unrollment pattern; the centre of pressure (CoP) travelled towards a maximum lateral deviation and returned towards the dorsopalmar/plantar axis of the hoof. Trimming decreased the intra‐individual left/right difference in maximum lateral displacement.Conclusions: The technique used provided easily accurate data to quantify hoof balance characteristics and to measure short‐term trimming effects.Potential relevance: Determination of CoP patterns has added value in gait analysis and can improve our understanding of the effects of different interventions on hoof balance.
Effects of girth, saddle and weight on movements of the horse
Authors: DE COCQ P. , VAN WEEREN P. R. , BACK W. 
Published: April 2007

SummaryReasons for performing study: Although the saddle is seen as one of the biggest causes of back pain, and weightbearing is seen as an important aetiological factor in ‘kissing spine’ syndrome (KSS), the effects of a saddle and weight on the back movements of the horse have never been studied.Objective: To determine the effects of pressure on the back, exerted by tack and weight, on movements of the horse.Hypothesis: Weight has an extending effect on the horse's back and, as a compensatory mechanism to this extension, an alteration in pro‐ and retraction angles was expected. A similar but smaller effect was expected from a saddle only and a lungeing girth.Methods: Data were captured during treadmill locomotion at walk, trot and canter under 4 conditions: unloaded; with lungeing girth; saddle only; and saddle with 75 kg of weight. Data were expressed as maximal extension, maximal flexion angles, range of motion of L3 and L5 and maximal pro‐ and retraction angles of the limbs.Results: At walk and trot, there was a significant influence on back kinematics in the ‘saddle with weight’ situation, but not in the other conditions. Overall extension of the back increased, but the range of movement remained the same. Limb kinematics changed in the sense that forelimb retraction increased. At canter, both the ‘saddle with weight’ and ‘saddle only’ conditions had a significant extending effect on the back, but there was no effect on limb kinematics.Conclusions and potential relevance: Weight and a saddle induce an overall extension of the back. This may contribute to soft tissue injuries and the KSS. The data from this study may help in understanding the reaction of the equine back to the challenges imposed by man when using the animal for riding.
Influence of rider on lameness in trotting horses
Authors: LICKA T. , KAPAUN M. , PEHAM C. 
Published: April 2007

SummaryReasons for performing study: Equine lameness is commonly evaluated when the horse is being ridden, but the influence of the rider on the lameness has not been documented.Objective: To document the effect of 2 riders of different training levels on the vertical movement of the head and croup.Methods: Twenty mature horses were ridden at trot by an experienced dressage rider and a novice rider, as well as trotted in hand. Kinematic measurements of markers placed on the horse's head and sacral bone were carried out. The asymmetries of the vertical head and sacral bone motion were calculated as lameness parameters and compared with pairedttests.Results: Trotting in hand, 17 horses showed forelimb lameness (1–4/10) and 13 hindlimb lameness (1–2/10). Intra‐individually, 11 horses showed significant differences in forelimb lameness and 4 horses showed significant differences in hindlimb lameness when ridden. Over all horses, hindlimb lameness increased significantly under the dressage rider compared to unridden horses.Conclusions: The presence of a rider can alter the degree of lameness; however, its influence cannot be predicted for an individual horse.Potential relevance: In order to evaluate mild lameness, horses should be evaluated at trot both under saddle and in hand. If lameness is exacerbated, a second rider may be helpful; the level of training of the rider should be taken into consideration.