bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of the anti‐inflammatory actions of flunixin and ketoprofen in horses applying PK/PD modelling
Authors: LANDONI MARIA F. , LEES P. 
Published: April 2010

SummaryA comparative study in horses of the pharmacokinetics (PK) and pharmacodynamics (PD) of 2 extensively used nonsteroidal anti‐inflammatory drugs (NSAIDs), flunixin (FXN) and ketoprofen (KTP), was carried out applying PK/PD modelling. To evaluate the anti‐inflammatory properties of these drugs a model of acute inflammation, comprising surgically implanted subcutaneous tissue cages stimulated by intracaveal injection of carrageenan, was used.FXN elimination half‐life (T1/2β) in plasma was 3.37 ± 1.09 h. However, in exudate a much longer T1/2β was obtained (15.99 ± 3.80 h). Apparent volume of distribution (Vdarea) for FXN was 0.317 ± 0.126 1/kg and body clearance (CIB) was 0.058 ± 0.004 1/kg/h. KTP displayed enantioselective pharmacokinetics, the S(+) enantiomer being predominant in plasma, exudate and transudate. T1/2β values for R(‐) and S(+)KTP were, respectively, 1.09 ± 0.19 h and 1.51 ± 0.45 h (plasma) and 19.73 ± 2.72 h and 22.64 ± 4.34 h (exudate), respectively. R(‐)KTP was cleared more rapidly than the S(+) enantiomer. C1B values were 0.277 ± 0.035 1/kg/h and 0.202 ± 0.022 1/kg/h, respectively.FXN and KTP pharmacodynamics was evaluated by determining their inhibitory effects on serum thromboxane (Tx)B2, exudate prostaglandin (PG)E2, leukotriene (LT)B4and β‐glucuronidase (β‐glu) and intradermal bradykinin‐induced swelling. Both drugs produced marked inhibition of serum TxB2synthesis for up to 24 h, with no significant differences between the drugs. FXN was a more potent inhibitor of exudate PGE2, the EC50 for FXN being lower (P<0.01) than that for KTP (0.019 ± 0.010 μg/ml and 0.057 ± 0.009 μg/ml, respectively). Neither drug had any effect on exudate LTB4concentration. Differences between the 2 drugs were observed for the inhibition of β‐glu, the Emax for KTP being higher (P<0.01) than for FXN. However, no differences were observed in other PD parameters. Both FXN and KTP inhibited bradykinin‐induced swelling. Differences between the drugs were obtained for Emax, which was greater for FXN (P<0.01) than for KTP. Equilibration half‐life (T1/2Ke0) also differed, being much longer (P<0.01) for FXN than for KTP.PK/PD modelling proved to be a useful and novel analytical technique for studying the pharmacodynamics of NSAIDs, with the advantage over classicalin vitromethods that it provides data in the whole animal. By quantifying action‐concentration interrelationships through PK‐PD modelling, it is possible to shed light on molecular mechanisms of drug action, and establish probable differences in mechanisms of action between structurally similar drugs. In future it should be possible to use PK/PD modelling to provide a rational basis for selecting dosage schedules for clinical use.
Changes in breathing pattern in the normal horse at rest up to age one year
Authors: KOTERBA ANNE M. , WOZNIAK J. A. , KOSCH R C. 
Published: April 2010

SummaryChanges in pattern of airflow, sequence of respiratory muscle activation and generated pressures were measured serially in a group of foals during the first year post partum, in order to describe the maturation of the equine breathing pattern. In neonatal foals, inspiration and expiration were both primarily active and airflow pattern was essentially monophasic. By age 1 year, foals displayed essentially the same breathing pattern previously described in adult horses, utilising a combination of active and passive inspiration and expiration to breathe around, rather than from, the relaxation volume of the respiratory system (V̇rx). A strong temporal relationship during growth was found between the timing of changes observed in airflow pattern and in the neuromuscular strategy of breathing. The transition to the adult breathing pattern appeared to involve a time delay in activation of both inspiratory and expiratory muscle groups, establishing a passive and active component to both inspiration and expiration. Throughout the study period, concurrent with the increase in delay of abdominal muscle activation, the expiratory flow pattern became progressively more biphasic in appearance. The time of appearance of a consistent biphasic inspiratory flow pattern was considerably later, at approximately age 1 year and coincided with the appearance of a delay in inspiratory muscle activation. From our results, we conclude that the transition from the neonatal to the adult breathing strategy in the horse appears not to be induced by the time course of chest wall stiffening during maturation. While changes in relative body proportions and size of abdominal contents during growth may influence the transition in breathing, our results also indicate that respiratory control mechanisms play an essential role in the expression of the polyphasic breathing pattern.
Effects of glyceryl trinitrate (nitroglycerin) on pulmonary vascular pressures in standing Thoroughbred horses
Authors: MANOHAR M. 
Published: April 2010

SummaryStrenuously exercising Thoroughbreds exhibit a dramatic increase in pulmonary capillary blood pressure, which contributes to stress failure of pulmonary capillaries resulting in exercise induced pulmonary haemorrhage (EIPH). One strategy to prevent EIPH is, therefore, to lower the pulmonary capillary blood pressure of exercising horses. Recent work in several species suggests that nitric oxide plays a significant role in maintaining low vascular resistance in the pulmonary circulation; however, the effects of nitrovasodilators (which work via the same mechanism as nitric oxide) on equine pulmonary circulation have not been examined. The present study examined the effects of glyceryl trinitrate (nitroglycerin) on right atrial and pulmonary vascular pressures in 7 healthy sound Thoroughbred horses. Freshly prepared nitroglycerin solution was infused for 240 s into the right atrium of quietly standing Thoroughbreds at dose rates of 350, 700, 1400 and 2100 g/min in a randomised manner. All infusions were performed in duplicate. Heart rate, right atrial, pulmonary artery, pulmonary capillary and pulmonary artery wedge pressures were determined preinfusion, at 30 s intervals during nitroglycerin infusions and at 60 s post infusion. Measurements were made using catheter mounted manometers whosein vivosignals had been matched with fluid‐filled systems referenced at the level of the point of the shoulder. It was observed that nitroglycerin infusions caused a dose related increase in heart rate while dose related reductions occurred in the mean right atrial, pulmonary artery, pulmonary artery wedge and pulmonary capillary pressures. At 2100 μg/min, nitroglycerin induced reduction in pulmonary artery wedge pressure was significantly greater than that in the pulmonary artery pressure. It is concluded that (i) pulmonary vascular bed of quietly standing horses has a certain basal vasomotor tone which was unmasked by nitroglycerin infusions (ii) nitroglycerin may have a more potent dilator effect on equine pulmonary veins than on the arteries.
Biokinematic effects of collection on the trotting gaits in the elite dressage horse
Authors: HOLMSTRÖM M. , FREDRICSON I. , DREVEMO S. 
Published: April 2010

SummaryTrot in hand, working trot, collected trot, passage and piaffe of 6 Grand Prix dressage horses were recorded by high speed film (250 frames/s). Angular patterns and hoof trajectories of the left fore‐ and hindlimbs were analysed and presented as mean and standard deviation (s.d.) curves. Speed and stride length decreased and fore‐ and hind stance phase durations increased with collection resulting in no suspension in piaffe. The diagonal advanced placement was positive in all gaits except for piaffe. Most of the changes in forelimb angular patterns were effects of reduction in forelimb pendulation. The horses did not step under themselves more in collected trot, passage and piaffe than in trot in hand. The stifle and hock joints were more flexed at the start of the stance phase in piaffe and passage than in the other gaits. Flexion of the hock joint at the middle of the stance phase was largest in passage and piaffe. In spite of the limited number of horses the present study confirmed earlier observations of conformation and gaits in dressage horses. Hindlimb pendulation, femur and pelvis inclinations and elbow, carpal, stifle and hock joint angles seem to be the most significant angular measurements for dressage performance.
Clinical features of the 1992 outbreak of equine viral arteritis in Spain
Authors: MONREAL L. , VILLATORO A. J. , HOOGHUIS H. , ROS I. , TIMONEY P. J. 
Published: April 2010

SummaryDuring 1992, a widespread outbreak of Equine viral arteritis (EVA) occurred at a riding establishment near Barcelona, Spain. A total of 31 out of 186 horses on the premises displayed clinical signs, most frequently, fever, depression, mild ventral and limb oedema and a vesicular‐erosive stomatitis, with hypersalivation, petechiations and small ulcerations. Affected horses developed illness of varying severity with only a few exhibiting a severe form of the disease and no mortality was recorded. Haematological and blood biochemical examination the most severely affected horses revealed a thrombocytopenia, slight leucocytosis with neutrophilia, lymphopenia and eosinopenia, an increase in plasma fibrinogen and a small rise in serum proteins and indirect bilirubin values. Diagnosis was confirmed by demonstration of seroconversion to equine arteritis virus in acute and convalescent phase sera. Attempted isolation of the virus from citrated blood samples proved unsuccessful.
Ophthalmic cyclosporine in equine keratitis and keratouveitis: 11 cases
Authors: GRATZEK ANN T. , KASWAN RENEE L. , MARTIN C. L. , CHAMPAGNE E. S. , WHITE SUSAN L. 
Published: April 2010

SummaryTopical cyclosporine A was safely used in a series of 11 cases of equine keratitis and keratouveitis and appeared to be an effective anti‐inflammatory agent in 9 cases. The clinical diagnoses included interstitial keratouveitis, endotheliitis, multifocal punctate keratopathy and a melting stromal ulcer. In most cases, the presence or absence of insidious bacterial infection was not conclusively determined. Topical cyclosporine A had no deleterious effects in this series of cases. The authors suggest that topical cyclosporine in both aqueous and lipid base vehicles should be investigated and evaluated as an alternative mode of achieving ocular immunosuppression.
Harem stability and reproductive success of Misaki feral mares
Authors: KASEDA Y. , KHALIL A. M. , OGAWA H. 
Published: April 2010

SummaryThe stability of relationships between harem stallions and mares (consort relations) was investigated and the durations ofinter partumintervals were determined in order to establish if there was any correlation between the stability of consort relation and reproductive success of mares in Misaki feral horses. Thirty‐four mares were observed continuously for more than 5 years. The lifetime stability was 80–100% (mean 92.4%) for 16 mares, 60–79% (mean 70.4%) for 10 mares and 0–59% (mean 27.9%) for 8 mares. The continuous length (years) of specific consort relations was 2–10 years and was found to correlate significantly with lifetime stability. There was a significant positive correlation of lifetime stability with lifetime reproductive success for 34 mares observed, and the correlation was higher when the data of 8 wandering mares (<60% in lifetime stability) were omitted. The mean ± s.d. delivery interval of 25 stable mares was 364.5 ± 11.0 days, whereas that of 8 unstable mares and stable mares who changed stallions was 387.0 ± 40.2 days. There was a significant difference between delivery intervals of stable and unstable mares. Significant correlations between the stability of consort relations and both the foaling rates and delivery intervals suggest that mares may obtain major reproductive advantages if they maintain long term and stable consort relations with a particular stallion throughout their reproductive life span.
Ultrastructure of the secretory endometrium during oestrus in young maiden and foaled mares
Authors: TUNÓN A‐M. , RODRIGUEZ‐MARTINEZ H. , HAGLUND A. , ALBIHN A. , MAGNUSSON U. , EINARSSON S. 
Published: April 2010

SummaryCyclical accumulation of uterine fluid occurs during oestrus and is often seen in excessive volumes in mares considered susceptible to endometritis. Since the mechanisms behind the formation of free uterine fluid remain to be clarified, the fine structure of the secretory equine endometrium was studied in biopsies collected during videoendoscopy from 14 endometritis‐free, 4–9‐year‐old mares during oestrus. A distinct oedema of thetunica mucosawas evident. The surface epithelium had both ciliated and nonciliated cells and, particularly at the uterine body, often presented intra‐epithelial macrophages. The epithelial cells of the gland duct were similar to the surface epithelium, except that the nonciliated cells lacked secretory vesicles. The mid‐deep glandular segment was, however, loaded with apical secretory vesicles in the nonciliated cells. This glandular epithelium presented clear signs of secretory activity with conspicuous secretory vesicles holding electron‐dense granula in the adluminal cytoplasm and a well developed supranuclear Golgi apparatus. Secretory products as well as cell debris were commonly found in the lumen of the glands. No clear signs of apocrine secretion were found and it seemed therefore, that the mechanism of secretion is merocrine, i.e. by exocytosis. The endometrial oedema and intense secretory activity, both under oestrogenic influence, contribute to the building up of the uterine fluid during oestrus. No differences in morphology of the secretory endometrium could be noticed between nulliparous mares and mares that had had 1 or 2 foals.
Serial measurement of peripheral oestrogen and progesterone concentrations in oestrous mares to determine optimum mating time and diagnose ovulation
Authors: ALLEN W. R. , MATHIAS SUSANNA , LENNARD S. N. , GREENWOOD R. E. S. 
Published: April 2010

SummaryRapid enzyme‐based immunoassays were used to measure concentrations of oestradiol‐17ß and progesterone in daily blood samples recovered throughout oestrus and for a few days after ovulation from 34 Thoroughbred and 8 pony‐type maiden, barren and foaling mares. The first dectectable fall in oestradiol‐17ß levels occurred in 88% of the mares within the interval −72 to 0 h with respect to ovulation and in 65% of mares within the interval of −48 to 0 h. The results indicated that serial daily hormone assays of this type could, in a high proportion of animals, predict a correct time for a single mating and diagnose the occurrence of ovulation in Thoroughbred mares at stud in the absence of the present management system which includes repeated veterinary examinations of the ovaries. However, the absolute need for serial daily sampling from all mares to produce interpretable hormone profiles, and the cost of this sampling and the hormone assays, make the method impractical at the present time.
Nitric oxide donors as treatment for grass induced acute laminitis in ponies
Authors: HINCKLEY K. A. , FEARN S. , HOWARD B. R. , HENDERSON I. W. 
Published: April 2010

SummaryThe potential for participation of the arginine‐nitric oxide system in the aetiology of acute equine laminitis has been assessed. Nitric oxide (NO), produced by the action of NO synthase (NOS) on its substratel‐arginine, relaxes vascular smooth muscle to cause vasodilatation. An attenuated normal vasodilatory tone may characterise the pathogenesis of acute equine laminitis. An intravenous infusion of 10%l‐arginine in 0.9% saline caused vasodilatation in the hoof of a normal pony and immediate reperfusion of laminal tissues in an acutely laminitic pony, detected noninvasively by near infrared spectroscopy (NIRS), but the amino acid had little effect on systemic blood pressure. Treatment of acute laminitis with glyceryl trinitrate applied topically to the pasterns reduced the typical ‘bounding pulses’ in treated limbs, reduced lameness and lowered systemic blood pressure. Nitric oxide is likely to participate in the multifactorial pathogenesis of equine laminitis.
Determination of highest no effect dose (HNED) for local anaesthetic responses to procaine, cocaine, bupivacaine and benzocaine
Authors: HARKINS J. D. , MUNDY G. D. , STANLEY S. , WOODS W. E. , REES W. A. , THOMPSON K. N. , TOBIN T. 
Published: April 2010

SummaryThe highest no effect doses (HNEDs) for the local anaesthetic (LA) effects of procaine, cocaine, bupivacaine and benzocaine were determined using the heat lamp/hoof withdrawal model of Kamerlinget al. (1985b) and the abaxial sesamoid block model of local anaesthesia. The heat lamp rapidly (4 or 5 s) increased the temperature of the superficial skin layers of the pastern to about 90°C, at which point the animal sharply withdrew its hoof. Effective LA blockade precluded this response and superficial skin temperatures exceeded 120°C. Thermal stimulus experiments were routinely terminated after 10 s of exposure to prevent undue tissue damage.Following abaxial sesamoid block with bupivacaine, the HNED for that drug was about 0.25 mg/site. Increasing the dose to 2 mg/site apparently produced complete and prolonged LA blockade.Analogous work showed that the HNED for procaine was about 2.5 mg/site. Similarly, the dose response curve for procaine was parallel with that of bupivacaine but was shifted 10‐fold to the right The duration of the LA response following procaine injection was less than for bupivacaine with the statistically significant response following 40 mg/site injection lasting less than 45 min.Cocaine was less potent than procaine, showing a shallower dose response curve. The HNED for cocaine was less than 5 mg/site, although at this dose the duration of action was extremely short (<7.5 min). Benzocaine had no significant LA action when a dose of 800 mg was applied topically as a 5% preparation.These results show that the HNEDs for bupivacaine and procaine are remarkably low, that cocaine is somewhat less potent as a LA than might be expected, and that 5% topical benzocaine has no significant pharmacology. The small doses of bupivacaine and procaine producing effective local anaesthesia suggests that developing plasma thresholds for these agents is likely to be very challenging.
Basement membrane pathology: a feature of acute equine laminitis
Authors: POLLITT C. C. 
Published: April 2010

SummaryThirty‐two dorsal, mid‐hoof wall, lamellar sections from 8 Standard bred horses, humanely killed 48 h after the administration of an alimentary carbohydrate overload, were sectioned and examined by light microscopy. Sections were stained with the connective tissue and basement membrane stains periodic acid‐Schiff (PAS), Azan and periodic acid silver methanamine (PASM) and with routine haematoxylin and eosin (H&E). Lesions of the epidermal lamellae, attributable to laminitis, were graded in order of increasing severity fromGrade N(normal),Grade 1(mild),Grade 2(moderate) toGrade 3(severe and extensive). The grading system was based principally on changes to lamellar basement membrane (BM) which were clearly visible when the connective tissue stains PAS and PASM were used. Earliest changes were rounding of the basal cell nuclei and elongation of secondary epidermal lamellae (SELs). Secondary epidermal lamellae tips were pointed instead of round and the basement membrane had separated from the lamellae. In earlyGrade 1lesions, this was obvious at the tips of the SELs where the BM had lifted to form teat‐shaped bubbles. The absence of BM at the tips of secondary dermal lamellae, along with varying amounts of connective tissue, was considered a progression in severity and classified asGrade 2. Eventually, even the primary epidermal and primary dermal lamellae separated from each other and the empty shells of isolated BM, in what was once the tip of the primary epidermal lamella, signified that a global separation of the epidermal and dermal lamellae had occurred (Grade 3lesion). The histopathological grading system correlated well with the degree of lameness at the time of euthanasia, (r2= 0.94) and apparently described the severity of laminitis accurately. Disintegration of the BM and failure of its attachment to the basal cells of the epidermis appears to be one of the earliest pathological events to occur in acute laminitis and could be the change that initiates the collapse of the lamellar architecture. Histopathological diagnoses of laminitis are strengthened when based on sections stained with at least PAS, in addition to routine H&E and should exhibit evidence of the BM pathology described here.
Ultrasonographic anatomy of the dorsal and abaxial aspects of the equine fetlock
Authors: DENOIX J. M. , JACOT STEPHANIE , BOUSSEAU B. , PERROT PATRICIA 
Published: April 2010

SummaryThis paper describes normal ultrasound images of the soft tissues of the dorsal and abaxial aspects of the equine fetlock. The palmar aspect of the fetlock is not discussed because it is related to the suspensory apparatus and flexor tendon anatomy which has been previously described. Ultrasound scanning was performed with 7.5 MHz linear or 10 MHz sector probes and recorded on 7.5 cm U‐matic videocassettes allowing further retrospective data analysis, computer manipulation and good image reproducibility. Sagittal, parasagittal, frontal and transverse ultrasound scans of 13 lameness free mature horses were compared to anatomically dissected leg specimens, anatomical sections and Magnetic Resonance Imaging scans of isolated limbs. The results are focused on the comparison between anatomical sections and ultrasonograms performed on the legs of nonlame horses. Ultrasonography was demonstrated to be a very accurate imaging procedure for soft tissue structures at the dorsal and abaxial aspects of the equine fetlock. Under clinical conditions, a thorough knowledge of normal ultrasonographic anatomy is critical for an accurate diagnosis of fetlock soft tissue injury.
Retinal detachment in horses
Authors: Mätz‐Rensing Kerstin , Drommer W. , Kaup E‐J. , Gerhards H. 
Published: April 2010

SummaryTen horses with partial or total retinal detachment were investigated using light and electron microscopy (TEM, SEM). Several lesions were observed and compared with normal retinal morphology. Three weeks after the initial retinal detachment, hypertrophy of the pigment epithelium with transformation of the apical microvilli could be observed. The lesions were accompanied by progressive degeneration and atrophy of the sensory retina, starting at the photoreceptor outer segments. Hypertrophy of Müller cells was a concomitant finding. Retinal detachment represents a sequel either to inflammatory processes or trauma.