bluuebunny/crossref_metadata_2025_split huggingface dataset:
Equine pulmonary and systemic haemodynamic responses to endothelin‐1 and a selective ETA receptor antagonist
Authors: BENAMOU A. E. , MARLIN D. J. , LEKEUX P. 
Published: April 2007

SummaryBased on previous in vitro studies, we hypothesised that endothelin (ET) would induce vasoconstriction in the pulmonary circululation of the horse and that this action would be mediated via ETA receptors. Pulmonary and systemic haemodynamic responses to endothelin‐1 (ET‐1), a potent vasoactive endogenous peptide, were investigated in 6 conscious, nonsedated horses at rest. Bolus i.v. injections of exogenous ET‐1 (0.1, 0.2 and 0.4 μg/kg bwt) caused significant increases in pulmonary (PAP) and carotid (CAP) artery pressures, with peak increases of 79% and 51% for mean PAP and CAP, respectively. The effect of ET‐1 on PAP and CAP was rapid and transient for PAP (∼10 min) but prolonged for CAP (up to 60 min). ET‐1 significantly decreased cardiac output by up to 35% and significantly increased systemic vascular resistance (SVR) by up to 104%. Pulmonary vascular resistance (PVR) showed a trend (P>0.05) to increase with 0.2 and 0.4 μg/kg bwt ET‐1. Infusion of a selective ETA receptor antagonist (TBC11251) completely inhibited the responses to a subsequent bolus of 0.2 μg/kg bwt ET‐1. We conclude that exogenous ET‐1 exerts a potent vasoconstrictive action on the pulmonary and systemic circulations of the horse. These effects appear to be mediated largely through ETA receptors in both circulations. Endothelin may play a role in hypertensive conditions in the horse.
A comparison of the effects of local analgesic solution in the navicular bursa of horses with lameness caused by solar toe or solar heel pain
Authors: SCHUMACHER JIM , SCHUMACHER JOHN , GRAVES F. de , SCHRAMME M. , SMITH R. , COKER M. , STEIGER R. 
Published: April 2007

SummaryWe hypothesised that analgesia of the navicular bursa is not selective for the navicular apparatus; and that solar pain in some horses can be temporarily abolished or attenuated by analgesia of the navicular bursa. To test this hypothesis, we caused lameness in horses by inducing pain in the dorsal margin or the angles of the sole and then evaluated the ability of a local analgesic solution administered into the navicular bursa to attenuate lameness.The response of horses with solar pain in the dorsal or palmar aspect of the foot to 3.5 ml local analgesic solution administered into the navicular bursa was examined. Lameness was induced in 6 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot, with set‐screws inserted into a custom‐made shoe. Horses were videotaped trotting before and after application of set‐screws and after administering 3.5 ml local analgesic solution into the navicular bursa. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P<0.05) for all horses with set‐screws applied to the dorsal margin of the sole after administration of local analgesic solution into the navicular bursa. In conclusion, analgesia of the navicular bursa was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole. Pain arising from the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the navicular bursa.
Joint moments in the distal forelimbs of jumping horses during landing
Authors: MEERSHOEK L. S. , ROEPSTORFF L. , SCHAMHARDT H. C. , JOHNSTON C. , BOBBERT M. F. 
Published: April 2007

SummaryTendon injuries are an important problem in athletic horses and are probably caused by excessive loading of the tendons during demanding activities. As a first step towards understanding these injuries, the tendon loading was quantified during jump landings. Kinematics and ground reaction forces were collected from the leading and trailing forelimbs of 6 experienced jumping horses. Joint moments were calculated using inverse dynamic analysis. It was found that the variation of movement and loading patterns was small, both within and between horses. The peak flexor joint moments in the coffin and fetlock joints were larger in the trailing limb (−0.62 and −2.44 Nm/kg bwt, respectively) than in the leading limb (−0.44 and −1.93 Nm/kg bwt, respectively) and exceeded literature values for trot by 82 and 45%. Additionally, there was an extensor coffin joint moment in the first half of the stance phase of the leading limb (peak value 0.26 ± 0.18 Nm/kg bwt). From these results, it was concluded that the loading of the flexor tendons during landing was higher in the trailing than in the leading limb and that there was an unexpected loading of the extensor tendon in the leading limb.
Stabling is associated with airway inflammation in young Arabian horses
Authors: HOLCOMBE S. J. , JACKSON C. , GERBER V. , JEFCOAT A. , BERNEY C. , EBERHARDT S. , ROBINSON N. E. 
Published: April 2007

SummaryWe examined the effect of stabling on upper and lower airway inflammation in 14 yearling Arabian horses that had been at pasture since birth. Horses were divided into 2 groups of 7. One group was stabled for 3 months and the other remained at pasture. The groups were then switched over for another 3 months. The nasopharynx, guttural pouches and trachea were examined endoscopically and bronchoalveolar lavage performed every month. An upper airway inflammation score was devised based on the magnitude of pharyngeal lymphoid hyperplasia and guttural pouch inflammation. During stabling this score remained constant, whereas it decreased during the 3 months at pasture. Stabling was also associated with a higher number and percentage of neutrophils in bronchoalveolar lavage fluid and with a smaller percentage of lymphocytes. There was no correlation between upper airway inflammation score and bronchoalveolar lavage cytology. During a nasal occlusion test, dorsal displacement of the soft palate occurred more times in stabled than in pastured horses, but this was heavily biased by the results from one animal. We conclude that stabling is associated with inflammation of both the upper and lower airway of young horses.
Arthroscopic laser extirpation of metacarpophalangeal synovial pad proliferation in eleven horses
Authors: MURPHY D. J. , NIXON A. J. 
Published: April 2007

SummaryA new surgical technique for treatment of chronic metacarpophalangeal synovial pad proliferation in the horse and the findings and long‐term follow‐up from 11 clinical cases are described. The medical records of all equine lameness cases attributed to metacarpophalangeal synovial pad proliferation admitted to the College of Veterinary Medicine at Cornell University (1991–1996) were reviewed and all those treated surgically by laser extirpation were included in this study. Retrieved data included subject details, preoperative lameness, ultrasonography, radiography and synovial fluid evaluations and lesion histopathology. Lesions were ablated using a CO2or a Nd:YAG laser intra‐articularly with arthroscopic guidance. Long‐term follow‐up was provided by telephone conversation with owners or trainers. All horses had fetlock joint effusion and were lame at presentation. Mean synovial pad thickness measured ultrasonographically was 9.0 mm (range 6–15 mm). Seven horses (64%) had radiographic evidence of remodelling of the dorsal cortex of distal McIII and 3 horses (27%) had concurrent dorsal proximal P1 fractures. No postoperative complications were noted. All 11 horses returned to training within 90 days of surgery without recurrence of the lesion(s). Laser extirpation of metacarpophalangeal synovial pad proliferation using arthroscopic guidance provided a rapid, safe and efficient method for surgical removal of such lesions without complications or recurrence. This surgical technique provides a suitable alternative to more conventional treatments for chronic metacarpophalangeal synovial pad proliferation in horses, particularly for removal of very large, fibrotic masses.
Pulmonary and systemic effects of inhaled endotoxin in control and heaves horses
Authors: PIRIE R. S. , DIXON P. M. , COLLIE D. D. S. , McGORUM B. C. 
Published: April 2007

SummaryTo investigate whether inhaled endotoxin contributes to airway inflammation and dysfunction in stabled horses, control (n = 6) and asymptomatic heaves (previously termed chronic obstructive pulmonary disease)‐susceptible (n = 7) horses were given inhalation challenges with 20, 200 and 2000 μg of solubleSalmonella typhimuriumRa60 lipopolysaccharide (LPS). LPS inhalation induced a dose‐dependent neutrophilic airway inflammatory response in both groups. Inhalation with 2000 μg of LPS also induced detectable lung dysfunction in the heaves group. LPS inhalation did not alter clinical score, tracheal secretion volume orairway reactivity in eithergroup. The no‐response thresholds were lower for the heaves group (<20 μg for airway inflammation; 200 to 2000 μg for lung dysfunction) than for the control group (20 to 200 μg for airway inflammation; >2000 μg for lung dysfunction). To enable comparison of these threshold levels with airborne endotoxin concentrations in stables, horses also received a 5 h duration hay/straw challenge, during which the total and respirable airborne endotoxin concentrations were determined. Comparison of the effects of acute LPS inhalation and hay/straw challenges suggest that inhaled endotoxin is not the sole cause of heaves. However, it is likely that it contributes to airway inflammation, both in heaves horses in concert with other inhalants, and in normal horses when they are exposed to high levels in poor stable environments.
A comparison of the effects of two volumes of local analgesic solution in the distal interphalangeal joint of horses with lameness caused by solar toe or solar heel pain
Authors: SCHUMACHER JOHN , SCHUMACHER JIM , de GRAVES F. , STEIGER R. , SCHRAMME M. , SMITH R. , COKER M. 
Published: April 2007

SummaryThe response of horses, with solar pain in the dorsal or palmar aspect of the foot, to 6 or 10 ml local analgesic solution administered into the distal interphalangeal (DIP) joint was examined. Lameness was induced in 7 horses by creating solar pain in the dorsal aspect of one forefoot and, at another time, the palmar aspect of the other forefoot with set‐screws inserted into a custom‐made shoe. Horses were videotaped trotting before and after application of set‐screws and, in separate trials, after 6 or 10 ml local analgesic solution was administered into the DIP joint. Lameness scores were assigned by examining videotaped gaits. Scores were significantly lower (P ± 0.05) for horses with set‐screws applied to the angles of the sole and receiving 10 ml, but not 6 ml, local analgesic solution into the DIP joint. Scores were significantly lower (P<0.05) for all horses with set‐screws in the dorsal margin of the sole receiving either volume of local analgesic solution. Analgesia of the DIP joint was less effective in desensitising the angles of the sole than in desensitising the dorsal margin of the sole, and 10 ml local analgesic solution was more effective than 6 ml in desensitising these regions. The response of horses with solar pain to local analgesic solution in the DIP joint was influenced by the volume administered and the region of sole affected.
A long‐term study of 277 cases of equine sinonasal disease. Part 2: Treatments and results of treatments
Authors: TREMAINE W. H. , DIXON P. M. 
Published: April 2007

SummaryThe treatments of 277 horses with equine sinonasal disease (1984–1996), described by Tremaine and Dixon (2001), are reported here. Long‐term (median duration 24 months) outcomes of treatment of the more common disorders were good, with 92% of horses with sinonasal mycosis, 84% with primary sinusitis, 82% with sinus cysts, 78% with dental sinusitis and 75% with sinonasal trauma reported to have complete remission of clinical signs. However, only 33% of horses with progressive ethmoidal haematoma (PEH) and 12% with sinonasal neoplasia reported long term remission of clinical signs.
The effects of treadmill inclination and speed on the activity of three trunk muscles in the trotting horse
Authors: ROBERT C. , VALETTE J. P. , DENOIX J. ‐M. 
Published: April 2007

SummaryThe purpose of this study was to evaluate the effects of speed and slope on the activity of trunk muscles. The electromyographic (EMG) activity of the splenius (Sp), longissimus dorsi (LD) and rectus abdominis (RA) muscles was recorded with surface electrodes during tread mill locomotion at trot fordifferent combinations of speed (3.5 to 6 m/s) and slope (0 to 6%). Raw EMG signals were processed to determine activity duration, onset and end and integrated EMG (IEMG).For the 3 muscles investigated, onset and end of activity were obtained earlier in the stride cycle when speed increased. A longer duration of activity forthe LD, a shorter duration for the RA and an unchanged duration for the Sp were also observed. The IEMG of the latter was poorly affected by speed, whereas it increased linearly with speed for the 2 other muscles.When treadmill inclination changed from 0 to 6%, EMG activity of the LD and RA began and ended later; a longer activity duration was noted. Temporal parameters for Sp did not change with slope. A significant and progressive increase in the IEMG of the 3 muscles was observed with increasing slope. This evaluation of the activity of trunk muscles provides objective data for the use of speed or slope in training programmes.
Differences in wound contraction between horses and ponies: the in vitro contraction capacity of fibroblasts
Authors: WILMINK J. M. , NEDERBRAGT H. , VAN WEEREN P. R. , STOLK P. W. T. , BARNEVELD A. 
Published: April 2007

SummaryThe contribution of wound contraction to wound closure determines the speed of second intention wound healing and it has been shown that significant differences exist with regard to both contraction and inflammatory response between horses and ponies and between various areas of the body. In this study, the contraction capacity of fibroblasts from limbs and buttocks of 4 Dutch Warmblood horses and 4 Shetland ponies was studied in vitro, in order to determine whether differences in wound contraction are due to differences in the inherent contraction capacity of the fibroblasts or to differences in tissue environmental factors, such as the inflammatory response.Fibroblasts were harvested from subcutaneous tissue, cultured and then suspended in both floating and anchored collagen gels. Contraction capacity was assessed by measuring the decrease in area of the floating gels and by measuring the microforces generated in the anchored gels using a custom‐built measuring device.In the floating gels, no difference existed in the contraction capacity of fibroblasts from horses and ponies, or from limbs and buttocks. In the anchored gels, no differences existed between horse and pony fibroblasts, but the fibroblasts from the limbs started to contract significantly soonerand produced significantly higherforces than those from the buttocks.It is concluded that the in vivo differences in wound contraction between horses and ponies and between different sites of the body are not caused by differences in the inherent contraction capacity of fibroblasts. The in vitro differences between fibroblasts from limbs and buttocks are thought to be due to the lower proliferation rate and the longer culture time of the fibroblasts originating from the limbs, because mature fibroblasts can develop higher contraction forces than immature fibroblasts. This means that tissue environmental factors, such as cytokine profiles during the inflammatory response, determine the extent of contraction during wound healing. Further research should be directed towards the role of the inflammatory response in wound healing.
Identification and characterisation of β‐adrenoceptors on intact equine peripheral blood lymphocytes with the radioligand (‐)‐[125I]‐iodocyanopindolol
Authors: ABRAHAM G. , BRODDE O.‐E. , UNGEMACH F. R. 
Published: April 2007

SummaryIn this study, β‐adrenoceptors of intact equine lymphocytes were identified and subclassified by (‐)‐[125I]‐iodocyanopindolol (ICYP) binding. ICYP binding to intact equine lymphocytes was rapid, saturable (maximal number of binding sites 320 ± 20 ICYP binding sites/cell, n = 12) and of high affinity (KD value for ICYP 14.4 ± 1.7 pmol/l, n = 12). Binding was stereospecific as shown by the 10 times greater potency of (‐)‐propranolol to inhibit binding than its (+)‐isomer. β‐adrenoceptor agonists inhibited ICYP binding with an order of potency: (‐)‐isoprenaline >(‐)‐adrenaline > (‐)‐noradrenaline; the same order of potency was obtained for agonist‐induced stimulation of lymphocyte cyclic AMPcontent.The selective β2‐adrenoceptor antagonist ICI 118,551 was about 1000 times more potent in inhibiting ICYP binding than was the β1‐selective adrenoceptor antagonist CGP 20712A. It is, therefore, concluded that in intact equine lymphocytes, ICYP labels a class of functional β‐adrenoceptors that belong predominantly (>90%) to the β2‐adrenoceptor subtype; a small (<10%) β1‐adrenoceptor component, however, cannot be ruled out completely. ICYP binding to equine lymphocytes might be a suitable model to study function and regulation of the β‐adrenoceptor system in the horse in vivo. The aim of this study was to characterise the β‐adrenoreceptor subtypes present on equine lymphocytes.
Organogenesis of lung and kidney in Thoroughbreds and ponies
Authors: BEECH D. J. , SIBBONS P. D. , ROSSDALE P. D. , OUSEY J. C. , HOLDSTOCK N. B. , CHAVATTE P. , ANSARI T. 
Published: April 2007

SummaryEquine lung and kidney organogenesis has not previously been examined with the use of unbiased stereological techniques. The present study examined healthy (control) pony and Thoroughbred lungs and kidneys to establish baseline data of organ development from before birth until maturity at age 3–18 years. Whole left lungs and kidneys were collected from 45 equine postmortem examinations (34 Thoroughbred, 11 pony). Stereological techniques were used to estimate whole kidney, cortex and medulla volume, total glomerular number and volume‐weighted mean glomerular volume, lung volume, total terminal bronchiolar duct ending number and total gas exchange surface area. Lungs were demonstrated to be more developed at birth in ponies compared with Thoroughbreds. Thoroughbreds showed continued lung development after birth, a unique micromorphogenic postnatal development. Kidneys were developed equally in ponies and Thoroughbreds. This study has provided data on the baseline development of the equiune lung and kidney which can be used in further studies to examine whether the development of these organs is affected by specific illnesses.
Zinc and copper plasma levels in Icelandic horses withCulicoideshypersensitivity
Authors: STARK G. , SCHNEIDER B. , GEMEINER M. 
Published: April 2007

SummaryZinc concentration has been shown to have a potent immunomodulatory capacity, particularly influencing T helper cell organisation and cytokine secretion.Culicoideshypersensitivity (CHS) in horses resembles the early and late phase oftype Ihypersensitive reactions in man, characterised by a shift from T helper cell subtype 1 to T helper cell subtype 2 cytokine profile. In this pilot study, zinc and copper levels were measured in the plasma of 48 CHS‐affected and 56 healthy Icelandic horses age 4–25 years (mean ˜ 11 years) kept on 7 farms. Affected horses were divided into 3 groups according to the severity of disease. Time of blood collection and feeding management was constant.No differences in zinc or copper plasma levels and plasma copper/zinc ratio were determined among CHS horses and controls by univariate analysis of variance. Therefore, the most significant influences on zinc and copper plasma levels were affected by the location of housing. However, Spearman correlation showed a negative coefficient between the plasma zinc concentration and the severity of CHS (r =−0.31). Due to a probability value of P = 0.002 the null hypothesis r = 0 is rejected, although only 9% of the total variation of plasma zinc is presently explained by its relationship to CHS. In contrast, the Spearman correlation coefficient between plasma copper levels and severity of CHS was not significant (r =−0.14; P = 0.16). The minor deviations in plasma zinc concentrations in association with the severity of CHS may be real or due to neurohumoral or cytokine‐mediated mechanisms, but appear too minimal to be relevant.
The hindlimb in walking horses: 2. Net joint moments and joint powers
Authors: CLAYTON H. M. , HODSON E. , LANOVAZ J. L. , COLBORNE G. R. 
Published: April 2007

SummaryThe objective of the study was to describe net joint moments and joint powers in the equine hindlimb during walking. The subjects were 5 sound horses. Kinematic and force data were collected synchronously and combined with morphometric information to determine net joint moments at each hindlimb joint throughout stance and swing. The results showed that the net joint moment was on the caudal/plantar side of all hindlimb joints at the start of stance when the limb was being actively retracted. It moved to the cranial/dorsal side around 24% stride at the hip and stifle and in terminal stance at the more distal joints. It remained on the cranial/dorsal side of all joints during the first half of swing to provide active limb protraction, then moved to the caudal/plantar aspect to reverse the direction of limb motion prior to ground contact. The hip joint was the main source of energy generation throughout the stride. It was assisted by the tarsal joint in both stance and swing phases and by the fetlock joint during the stance phase. The coffin joint acted as an energy damper during stance, whereas the stifle joint absorbed almost equal amounts of energy in the stance and swing phases. The coffin and fetlock joints absorbed energy as the limb was protracted and retracted during the swing phase, suggesting that their movements were driven by inertial forces. Future studies will apply these findings to detect changes in the energy profiles due to specific soft tissue injuries.