bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pulmonary vascular pressures of Thoroughbreds increase rapidly and to a higher level with rapid onset of high‐intensity exercise than slow onset
Authors: MANOHAR M. 
Published: April 2010

SummaryPrevious studies of pulmonary vascular pressures have utilised gradual incremental step exercise protocols, but in competitive racing at the track, horses perform rapid acceleration high‐intensity exercise. The rate of rise in pulmonary vascular pressures under conditions of quick onset high‐intensity exercise is unknown. Catheter mounted manometers, whosein vivosignals were matched with pressure signals obtained via transducers connected to fluid‐filled lumens from same cardiovascular sites, were used to compare right heart and pulmonary vascular pressures in 8 healthy Thoroughbreds performing 2 separate exercise protocols on a high speed treadmill (gradually incremental vs. rapid acceleration exercise protocol where the belt speed was raised from 8 m/s to 15 m/s in 8 s). Heart rate, right atrial and pulmonary vascular pressures at rest were similar for the 2 protocols. Rapid acceleration of horses from 8 to 15 m/s was attended by an equally rapid escalation in the right heart and pulmonary vascular pressures such that these pressures reached their zenith as belt speed approached 15 m/s. Although exercise at 15 m/s resulted in similar heart rate in the 2 protocols, the mean ± s.e. values of mean right atrial pressure, mean pulmonary artery pressure, mean pulmonary artery wedge pressure and mean pulmonary capillary pressure (91.5 ± 3.9 mmHg) in the rapid acceleration exercise were significantly (P<0.05) higher than respective values at 15 m/s in the gradual incremental step exercise protocol. It is concluded that pulmonary capillary blood pressure of Thoroughbreds rapidly accelerating to high‐intensity exercise increases just as rapidly as their speed and that the values achieved are higher than in incremental step exercise protocol; thereby playing a potential role in initiating stress failure of pulmonary capillaries and exercise‐induced pulmonary haemorrhage very early in a race.
An algorithm to describe the oxygen equilibrium curve for the Thoroughbred racehorse
Authors: SMALE K. , ANDERSON L. S. , BUTLER P. J. 
Published: April 2010

SummaryAn algorithm to describe the oxygen equilibrium curve (OEC) of the Thoroughbred horse was derived from raw oxygen equilibrium curve data obtained under standard conditions of temperature, pH and PCO2 (Smale and Butler, 1994). This algorithm was derived by a curve‐fitting procedure based on the algorithm for human blood produced by Kelman (1966). The temperature, fixed acid and net CO2 coefficients were then incorporated in the algorithm to enable the accurate calculation of % saturation from any combination of PO2, temperature, pH and PCO2. The algorithm was checked using blood gas data obtained from in vivo treadmill exercise tests as well as a standardised breathing test whereby horses inhaled several different gas mixtures. This algorithm proved more accurate for the Thoroughbred horse than that derived by Kelman.
Susceptibility of ponies to infection with Streptococcus pneumoniae (capsular type 3)
Authors: BLUNDEN A. S. , HANNANT D. , LIVESAY G. , MUMFORD JENNY A. 
Published: April 2010

SummaryWelsh Mountain ponies were inoculated with an isolate of Streptococcus pneumoniae, SPE 1618 (capsular type 3) recovered from the equine respiratory tract: 10 ml of a suspension of 108 or 109 cfu/ml were instilled intratracheally. Fever was observed after either dose but the greater concentration also produced coughing, ocular and nasal discharge, depression and enlargement of submandibular lymph nodes. Cytological evidence of infection was also observed in tracheal washings during the first week after inoculation and corresponded with isolation of S. pneumoniae from the washes. Morbid anatomical and histopathological examinations of selected animals revealed focal pneumonia affecting the ventral lung, especially the cardiac area and accessory lobe, with a propensity to affect the right lung. S. pneumoniae was isolated directly in pure culture from these lesions or was demonstrable by immunostaining of macrophages bearing specific capsular type 3 antigen. By 10 days after inoculation, the ponies were healthy and had developed antibodies to S. pneumoniae. S. pneumoniae was therefore a primary pathogen in the horse under the conditions of the challenge.
Ultrasonographic assessment of the proximal digital annular ligament in the equine forelimb
Authors: DIK K. J. , BOROFFKA S. , STOLK P. 
Published: April 2010

SummaryUltrasonography was used with 6 normal cadaver forelimbs of Dutch Warmblood horses to delineate the ultrasonographic anatomy of the palmar pastern region, with emphasis on the proximal digital annular ligament. Using a 5.5 MHz sector scanner, the thin proximal digital annular ligament was not visible on offset sonograms. Only if the digital sheath in the normal limb was distended was the distal border of this ligament outlined. In all normal limbs the palmarodistal thickness of the combined skin‐proximal digital annular ligament layer in the mid‐pastern region was 2 mm. The flexor tendons and distal sesamoidean ligaments were easily identified as hyperechoic structures. Distension of the digital sheath in the normal limbs clearly outlined the anechoic digital sheath pouches. In 4 lame horses ultrasonography aided the diagnosis of functional proximal digital annular ligament constriction. In all 4 diseased forelimbs ultrasonography demonstrated thickening of the skin‐proximal digital annular ligament layer and distension of the digital sheath. In one of these limbs the distended digital sheath was also thickened. The flexor tendons and distal sesamoidean ligaments were normal. There was no radiographic evidence of additional bone or joint lesions.
Transendoscopic electrocautery‐induced gastric ulcers as a model for gastric healing studies in ponies
Authors: MacALLISTER C. G. , LOWREY F. , STEBBINS M. , NEWMAN MARTHA S. , YOUNG BAMBI 
Published: April 2010

SummaryThe ponies were apparently healthy and 6–20 months of age. In Study 1, gastric lesions were created by transendoscopic electrocautery in the non‐glandular gastric mucosa, adjacent to the margo plicatus in 9 ponies which were then treated with water, 12 mg Cimetidine HCl/kg bwt or 18 mg Cimetidine HCl/kg bwtper osevery 12 h for 35 days. In Study 2, gastric lesions were similarly induced in 9 ponies in the non‐glandular mucosa and also in the glandular mucosa just below the non‐glandular lesion on the greater curvature of the stomach. The ponies were treated with water, 8 mg cimetidine/kg bwt or 16 mg cimetidine/kg bwtper osevery 8 h for 21 days. In both studies gastric lesion healing was monitored twice weekly by video gastroscopy. There was no apparent difference in healing times between the water and Cimetidine treatment groups in either study.These results indicate that uniform gastric ulcers can be created by transendoscopic electrocautery in the non‐glandular mucosa of ponies and that these ulcers heal at a predictable rate which should be useful in studying compounds that might accelerate healing of gastric mucosal lesions. However, Cimetidine was not effective in accelerating the rate of healing under the conditions of this study.
Serological and microbiological findings on 3 farms with equine leptospiral abortions
Authors: WILLIAMS DEBORAH M. , SMITH B. J. , DONAHUE J. M. , POONACHA K. B. 
Published: April 2010

SummaryBlood and urine samples from horses on 3 central Kentucky horse farms with prior histories of leptospiral abortions were analysed. Blood samples were obtained from all available horses on each farm and tested for antibodies to 6 leptospira serovars. Urine samples were collected from non‐gravid mares with serum antibody titres ≥1:800 and examined for leptospires by dark‐field microscopy, fluorescent antibody testing and culture. Adult horses had the greatest serological evidence of exposure to leptospira, followed by yearlings, then foals. Of horses with anti‐leptospiral antibodies, 76.3% reacted against serovarbratislava, 49.1% againsticterohaemorrhagiae, 20.1% againstgrippotyphosa, 16.3% againstpomonagenotypekennewicki, 15.9% againsthardjoand 1.0% againstcanicola.These findings confirmed that horses in central Kentucky are exposed to multiple leptospira serovars. The seroprevalence of antibodies to the 6 selected serovars was consistent among the 3 selected farms. There was no direct correlation between the serovar that was the cause of abortion in the previous season and prevalence of positive titres to that serovar in horses tested on the farms in the following year. Furthermore, there was no evidence of long‐term urinary shedding of leptospira by horses with high leptospira antibody titres.
Evaluation of pulse oximetry in horses surgically treated for colic
Authors: MATTHEWS NORA S. , HARTSFIELD SANDEE M. , SANDERS ELIZABETH A. , LIGHT GWENDOLYN S. , SLATER MARGARET S. 
Published: April 2010

SummaryAll 43 horses anaesthetised for colic surgery were premedicated with xylazine or diazepam. Anaesthesia was induced with guaifenesin and ketamine, horses were placed in dorsal recumbency and anaesthesia was maintained with isoflurane in oxygen and mechanical ventilation. Haemoglobin saturation readings (Spo2) were taken with a pulse oximeter and compared with computed haemoglobin saturation (Spo2) from arterial blood samples. Readings were taken over a range ofSpo2of 78–100%, mean arterial blood pressure ranged from 24 to 108 mmHg andPao2ranged from 53 to 490 mmHg.Analysis of 107 readings showed thatSpo2values predictedSpo2but time, blood pressure and individual horse did not. Correlation coefficients betweenSpo2andSpo2were 0.85 for all values and 0.88 for values at 30 min. Values for bias and precision were calculated for allSpo2values and for readings separated into 3 saturation groups: normal, low normal, and abnormal. The pulse oximeter tended to underestimateSpo2at all times, and was less precise as the saturation decreased.
Investigation of association between alpha‐1 proteinase inhibitor haplotype and endometritis in the Thoroughbred mare
Authors: PEMBERTON A. D. , JOHN H. A. , RICKETTS S. W. , ROSSDALE P. D. , SCOTT A. M. 
Published: April 2010

SummaryFailure to inhibit proteinases can lead to excessive tissue damage. The possibility that the severity of endometritis in Thoroughbred mares correlates with the haplotypes of plasma α1‐proteinase inhibitor (α1‐PI) expressed was investigated in two groups of mares. In mares with pyometritis before treatment, the frequency of the N haplotype, which is already high in the Thoroughbred population, was significantly increased when compared with that in a large published population. In mares with acute endometritis which persisted after treatment followed by sexual rest, the absence of S and T haplotypes was significant, suggesting that, when present, they may have a protective function.
The prevalence of latent Equid herpesviruses in the tissues of 40 abattoir horses
Authors: EDINGTON N. , WELCH H.M. , GRIFFITHS L. 
Published: April 2010

SummaryEquid herpesviruses 1 or 4 (EHV‐1 or −4) were isolated by co‐cultivation from 60% of 40 horses examined at slaughter. The lymph nodes draining the respiratory tract were the most common source of virus. EHV‐1 or EHV‐4 was never isolated from the trigeminal ganglia (SLG). The polymerase chain reaction (PCR) detected virus in 87.5% of bronchial lymph nodes and a similar level in the trigeminal ganglia that were examined. By both assays approximately one third of the positive animals harboured both viruses.Equid herpesvirus 2 (EHV‐2) was isolated from all but one of the horses and from >75% of the lymph nodes draining the respiratory tract; a viruses were isolated only in the presence of EHV‐2.The results indicate that latent EHV‐1 and EHV‐4 are widespread in the equine population and that the primary site of latency is the lymph nodes of the respiratory tract.
Progression and association with lameness and racing performance of radiographic changes in the proximal sesamoid bones of young Standardbred trotters
Authors: GRØNDAHL A. M. , GAUSTAD G. , ENGELAND A. 
Published: April 2010

SummaryRadiographic examination of the metacarpo‐ and metatarsophalangeal joints was performed on 753 Standardbred trotters (6–21 months of age): 21 showed obvious changes in 26 proximal sesamoid bones on lateromedial projection. The radiographic changes were divided into 6 different types: (1) irregular abaxial margin (8 horses); (2) enlargement of the sesamoid bone (6 horses); (3) ‘fracture’ or separate centre of ossification of the apex (4 horses); (4) vertical, non‐articular fracture of the plantar part of the sesamoid bone (1 horse); (5) a small bony fragment located in a defect in the apical part of the bone (2 horses); and (6) multiple areas of decreased radiodensity (1 horse). Each horse displayed only one type of radiographic change except for one which possessed those of types 3 and 5. Follow‐up radiographic examination of 21 of the 26 affected proximal sesamoid bones at ˜6‐month intervals revealed a reduction in the changes in 13 bones and an unaltered condition in 8. Lameness examination was performed on 16 of the 21 horses at 3 years of age and 14 (87.5%) were observed to be lame, but detected lameness did not seem to be referrable to the sesamoid changes. Earnings after the racing season as 3‐ and 4‐year‐old horses showed no differences (P>0.05) between horses with radiographic changes in the proximal sesamoid bones and those without such changes.
Effects of centrifugation and specimen preparation technique on bronchoalveolar lavage analysis in horses
Authors: LAPOINTE J.‐M. , VRINS A. , LAVOIE J.‐P. 
Published: April 2010

SummaryBronchoalveolar lavages (BAL) were performed for 6 healthy horses and 8 horses with lower airway diseases (LAD). Total cell and differential counts were performed before and after centrifugation and resuspension of the BAL cells in a small volume of fluid; there was no difference in the total cell counts, but mast cell percentages were significantly (P<0.05) lower, after centrifugation, in the LAD group. The two specimen preparation techniques compared were cytocentrifugation and centrifugation on microscope glass covers. For both groups of horses, lymphocyte percentages were significantly lower on cytocentrifuged specimens; there was also an increase in the other predominant cell type, i.e. macrophages in healthy horses and neutrophils in horses with LAD. Lymphocyte percentages in healthy horses were higher than those reported in previous studies, possibly because of a long‐standing exposure to a high‐dust environment. This study suggests that one centrifugation of the BAL fluid does not affect total cell counts, but may cause a decrease in mast cell percentage; cytocentrifugation is associated with a consistent decrease in lymphocyte percentage.
Differential scanning calorimetric studies of superficial digital flexor tendon degeneration in the horse
Authors: MILES C. A. , WARDALE R. J. , BIRCH H. L. , BAILEY A. J. 
Published: April 2010

SummaryDifferential scanning calorimetry (DSC) of equine superficial digital flexor tendons revealed the presence of a small exothermic peak at 23°C of unknown origin, and a large endothermic peak at 70°C due to denaturation of cross‐linked collagen fibres. In the central degenerated core of damaged tendons the denaturation temperature remained at 70°C but the enthalpy decreased in relation to the extent of degeneration of the tendon. We suggest that this reduction in enthalpy is due to depolymerisation and denaturation of the collagen fibres. This contention is supported by the observed increased activity of the degradative enzyme cathepsin B secreted by the fibroblasts. DSC analysis of cultured porcine tendon fibroblasts revealed a multicomponent endotherm, denaturation beginning at 46°C, a temperature capable of being achieved within the tendon during intensive exercise. DSC clearly has considerable potential in complementing morphological and biochemical studies to determine the aetiology and progress of equine tendon degeneration.
Effect of route of administration and age on the pharmacokinetics of amikacin administered by the intravenous and intraosseous routes to 3 and 5‐day‐old foals
Authors: GOLENZ M RENÉE , WILSON W. D. , CARLSON G. P. , CRAYCHEE THERESE J. , MIHALYI JUDITH E. , KNOX LINDA 
Published: April 2010

SummaryThe suitability of the intraosseous (i.o.) route for drug administration to equine neonates was evaluated in a study comparing the pharmacokinetics of amikacin administered by the i.o. and intravenous (i.v.) routes. Using a cross‐over study design amikacin sulphate (7 mg/kg bwt) was administered i.o. or i.v. to 6 healthy foals at 3 and 5 days of age. Amikacin was instantaneously and completely absorbed after i.o. administration, achieving a mean ± sd peak concentration (34.17 ± 3.54 μg/ml) in the first sample collected 3 min after administration which was not significantly different from the mean ± sd peak concentration (32.92 ± 2.63 μg/ml) achieved after i.v. administration. The plasma amikacin concentration‐time profiles for the i.o. and i.v. routes were not different and both were appropriately described by a 2‐compartment open pharmacokinetic model. No significant differences attributable to route of administration were found in values for the major pharmacokinetic variables. The degree of inter‐individual variation in values for indices of clearance was considerably greater than the degree of variation attributable to age. Despite this, values for body clearance (C***lB) were significantly higher (P<0.05) and values for area under the plasma amikacin concentration‐time curve (AUC) and concentration of amikacin in plasma at 8 h [Cp(8h)] were significantly lower in 5‐ than in 3‐day‐old foals, indicating that amikacin was more rapidly cleared by the older foals. Technical difficulties were not encountered during i.o. needle placement in the medial aspect of the proximal tibia. Mild diffuse soft tissue swelling which developed at the i.o. site resolved completely within 1–2 months. Radiographs demonstrated a bony healing process with minor periosteal and endosteal proliferation. The i.o. route appears to be safe, practical and effective for rapid delivery of amikacin to neonatal foals.
Exercise induced ventilation/perfusion inequality in the horse
Authors: SEAMAN J. , ERICKSON B. K. , KUBO K. , HIRAGA A. , KAI M. , YAMAYA Y. , WAGNER P. D. 
Published: April 2010

SummaryExercise in normal human subjects causes deterioration of matching of ventilation to blood flow in the lungs, but only in about 50% of those examined. A previous study (Wagner et al. 1989) of 5 horses showed no significant worsening of ventilation/blood flow (V̇a/Q̇) relationships during heavy exercise as determined by multiple inert gas elimination technique (MIGET). Because of the small number of horses in that study and the 50% human incidence of exercise induced V̇a/Q̇ mismatch, we studied an additional 6 Thoroughbreds, comparing V̇a/Q̇ relationships at the walk (1.4 m/s, 0o incline) and during galloping (9.6 ± 0.3 m/s, 7% incline). Such data were collected under 4 different conditions wherein inspired gas was 1) air, 2) 21% O2 in helium, 3) 15% O2 in N2 and 4) 15% O2 in helium. Each horse exercised 4 times (morning and afternoon of 2 days, with inspired gas conditions randomised). There was a small but significant increase in V̇a/Q̇ mismatch (similar under all 4 conditions). The second moment of the V̇a/Q̇ distribution (determined by the MIGET) increased significantly (P < 0.01) from 0.31 ± 0.01 at the walk to 0.38 ± 0.02 during gallop. This increase however is small: 0.38 is well within the range of this parameter for normal human subjects (where the 95% upper confidence limit is 0.60). This study shows that a small amount of exercise induced V̇a/Q̇ mismatch can occur in the horse as in man, but the mechanism remains to be elucidated and its clinical significance remains to be established. It may reflect interstitial pulmonary oedema but effects on arterial oxygenation are minimal.
Distribution of inspired gas to each lung in the anaesthetised horse and influence of body shape
Authors: MOENS Y. , LAGERWEIJ E. , GOOTJES P. , POORTMAN J. 
Published: April 2010

SummaryThe distribution of inspired gas to each lung, time constants of the lungs and parameters of gas exchange were studied in 2 groups of horses (mean bwt 606 kg), anaesthetised using thiopentone and chloral hydrate and breathing room air. One group (n=4) had a downward curved abdominal contour (round‐bellied) and the other group (n=4) had an upward curved abdominal contour (flat‐bellied). An equal distribution of inspired gas between the lungs existed in both groups in dorsal recumbency. Flat‐bellied horses maintained this equal distribution in lateral recumbency whereas in round‐bellied horses an uneven distribution of tidal volume (VT) developed. The percentage of (VT) distributed to the dependent lung was 23% and 38% for left and right lateral recumbency respectively. The distribution of VTagreed with the ratio of time constants of the lungs in flat‐bellied horses but differed markedly from this ratio in round‐bellied horses suggesting that, in the latter, factors other than compliance and resistance play a role in distribution of ventilation. Round‐bellied horses had a lower PaO2and a larger (A‐a)PaO2than flat‐bellied horses in all body positions. The results are compatible with the known hypothesis that pressure exerted by abdominal contents on the dependent lung and diaphragm is an important factor in ventilation/perfusion mismatch of the anaesthetised horse.