bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prednisoneper osis likely to have limited efficacy in horses
Authors: PERONI D. L. , STANLEY S. , KOLLIAS‐BAKER C. , ROBINSON N. E. 
Published: April 2007

SummaryBased on its efficacy for the treatment of human asthma, the corticosteroid prednisone is commonly used in horses for treatment of recurrent airway obstruction. However, recent studies have failed to show any benefit of prednisone tablets for the treatment of this condition. The purpose of this study was to determine why oral prednisone has poor efficacy for the treatment of heaves in horses. In a crossover study, 5 horses were given the following treatments: prednisone tablets, prednisone liquid, prednisolone tablets, prednisolone liquid and i.v. prednisolone sodium succinate (positive control). Blood samples were taken before drug administration and at selected time points during a 24 h period. Serum concentrations of prednisone and prednisolone were determined in order to evaluate gastrointestinal absorption and hepatic metabolism. Serum concentrations of the endogenous glucocorticoid hydrocortisone were also determined as an indicator of the biological activity of the drugs. Both prednisolone tablets and liquid were absorbed rapidly, with prednisolone detectable in serum within 15 min of administration and with peak concentrations occurring within 45 min. Small amounts of prednisone were detected in the serum samples after administration of both prednisone tablets and liquid. Prednisolone was not detected in serum samples after administration of prednisone liquid and was detected in serum samples from only one horse after administration of prednisone tablets. Endogenous hydrocortisone production was suppressed when horses received prednisolone. The results of these studies indicate that prednisone has poor efficacy for the treatment of heaves because it is poorly absorbed and the active metabolite prednisolone is rarely produced. In contrast, prednisolone tablets have excellent bioavailability and should be useful as a therapeutic agent in horses.
Cytological analysis of equine bronchoalveolar lavage fluid. Part 1: Comparison of sequential and pooled aliquots
Authors: PICKLES K. , PIRIE R. S. , RHIND S. , DIXON P. M. , McGORUM B. C. 
Published: April 2007

SummaryThe aim of this study was to investigate whether initial equine bronchoalveolar lavage fluid (BALF) aliquots were more representative of bronchial cytology that bronchiolar and alveolar cytology. Cell viability and total nucleated (TCC), differential (DCC) and absolute cell counts of cytocentrifuged preparations of 3 sequentially collected BALF aliquots (Aliquots 1–3) were compared with those of pooled BALF (Aliquot 4) to assess whetherall aliquots were representative of the lavaged lung segment. BALF samples (n = 21) were collected from control horses (n = 5) orheaves‐affected horses (n = 5). There were nonsignificant trends of increasing TCC and absolute macrophage count fromAliquot 1toAliquot 3and significant differences in macrophage (P<0. 05) and lymphocyte (P<0.01) DCC among aliquots of all horses; however, no linear trend in this DCC data was observed. There was a significant decrease in mast cell DCC (P<0.01) fromAliquot 1toAliquot 3in control horses. Cell viability did not differ significantly among aliquots. There was no diagnostically significant difference in TCC, DCC, absolute cell counts or cell viability, among sequential and pooled BALFaliquots and, therefore, all aliquots can be considered to represent the cytology of the lavaged lung segment. This indicates that even if BALF recoveries are very low, cytological analysis of samples will be of diagnostic value.
Development of biochemical heterogeneity of articular cartilage: influences of age and exercise
Authors: BRAMA P.A. J. , TeKOPPELE J. M. , BANK R. A. , BARNEVELD A. , van WEEREN P. R. 
Published: April 2007

SummaryThe objective of this study was to document the development of biochemical heterogeneity from birth to maturity in equine articular cartilage, and to test the hypothesis that the amount of exercise during early life may influence this process. Neonatal foals showed no biochemical heterogeneity whatsoever, in contrast to a clearbiochemical heterogeneity in mature horses. The process of formation of site differences was almost completed in exercised foals age 5 months, but was delayed in those deprived of exercise. For some collagen‐related parameters, this delay was not compensated for after an additional 6 month period of moderate exercise.It is concluded that the functional adaptation of articular cartilage, as reflected in the formation of biochemical heterogeneity in the horse, occurs forthe most part during the first 5 monthspostpartum. A certain level of exercise seems essential forthis process and withholding exercise in early life, may result in a delay in the adaptation of the cartilage.
Cytological analysis of equine bronchoalveolar lavage fluid. Part 2: comparison of smear and cytocentrifuged preparations
Authors: PICKLES K. , PIRIE R. S. , RHIND S. , DIXON P. M. , McGORUM B. C. 
Published: April 2007

SummaryThe aim of this study was to develop a diagnostically useful smear method for preparation of equine bronchoalveolar lavage fluid (BALF) for use by practitioners. A smear method for equine BALF preparation which included the addition of serum was developed, and cell morphology, differential cell counts (DCC) and repeatability of counting DCC compared with those of cytocentrifuged BALF preparations. BALF samples (n = 21) were collected from 5 control horses and 5 heaves‐susceptible horses. Smear preparations of BALF produced smaller, darker, staining cells, making cytological identification more difficult than on cytocentrifuged preparations. There was a significantly higher (P<0.0 1) macrophage DCC and lower lymphocyte DCC on cytocentrifuged compared to smear preparations. Mast cell and eosinophil DCC were significantly higher (P<0.05) on cytocentrifuged compared to smear preparations of BALF. Smear preparations were shown to be reliable for the cytological diagnosis of equine neutrophilic pulmonary disease and offerpractitioners an alternative to sending equine BALF to a laboratory for processing and cytological analysis.
Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 1: Preparation and composition of HDS
Authors: PIRIE R. S. , McLACHLAN G. , McGORUM B. C. 
Published: April 2007

SummaryCurrently, heaves is investigated by exposing susceptible horses to dusty hay. Consequently, the response will be dependent on the organic dust content and composition of the hay. It was hypothesised that the use of a hay dust suspension (HDS) would reduce the variability of the challenge and therefore standardise experimental protocols. Furthermore, analysis of HDS would also permit further investigation of the organic dust components responsible for the response. Three hay dust suspensions (HDS‐1, 2 and 3) were prepared for use in the diagnosis and investigation of heaves. HDS were produced from fine dust particles, comprising mostly fungal spores, collected from 3 batches of dusty hay. HDS‐1 and 3 were analysed for endotoxin, β‐D‐glucan and protein concentrations, general protease activity and enumeration and size distribution of particulates. Protease activity was mainly attributable to a 28kDa serine protease and to 85kDa and 160kDa metalloproteases. The particulate and soluble components of HDS could be aerosolised by jet nebulisation. We therefore conclude that detailed analysis of HDS is possible, that such a challenge system provides a method of standardising experimental protocols and that all components of HDS (both soluble and particulate) can be delivered to the lung using standard nebulisation techniques. For the above reasons, nebulised HDS offers considerable advantages over conventional hay/straw challenge for the diagnosis and investigation of heaves.
Effect of tapered normal and interval training on performance of Standardbred pacers
Authors: SHEARMAN J. P. , HAMLIN M. J. , HOPKINS W. G. 
Published: April 2007

SummaryHuman athletes taper or reduce their training load before a race to enhance performance, apparently because recovery from the effects of fatigue occurs faster than the loss of fitness from the reduced training. However, there appear to be no previous studies of tapering of equine athletes. Our aim in the present study was, therefore, to investigate the efficacy of tapering with Standardbred pacers. We determined the effect of repeated cycles of tapered training on performance of Standardbred pacers. After 8 weeks of jogging and 3 times 2 week cycles of pace work, 19 horses were randomised to a taper and a control group. The taper group completed 5 consecutive 2 week cycles, each incorporating a 7 day taper; some cycles included high‐intensity interval training. The control group continued with 5 more cycles of pace work. All horses completed a 2400 m individual time trial after each cycle. Peak and mean speed of the taper group were faster than those of the control group in all cycles; the differences were clear‐cut in all cycles for peak speed (overall 4.4%, 95% confidence interval 1.7 to 7.1%), but only in one of the interval‐training cycles for mean speed (2.4%, 0.3 to 4.7%). Four horses in the taper group were injured during interval training. Repeated tapering produces a worthwhile enhancement of performance in Standardbreds, but the addition of interval training appears to increase the risk of injury.
Pharmacokinetics of marbofloxacin in mature horses after single intravenous and intramuscular administration
Authors: CARRETERO M. , RODRÍGUEZ C. , ANDRÉS M. I. SAN , FORÉS P. , LUCAS J.J. de , NIETO J. , WAXMAN S. , ANDRÉS M. D. SAN , GONZÁLEZ F. 
Published: April 2007

SummaryThe pharmacokinetic behaviour of marbofloxacin, a new fluoroquinolone antimicrobial agent developed exclusively for veterinary use, was studied in mature horses (n = 5) after single‐dose i.v. and i.m. administrations of 2 mg/kg bwt. Drug concentrations in plasma were determined by high performance liquid chromatography (HPLC) and data obtained were subjected to compartmental and noncompartmental kinetic analysis. This compound presents a relatively high volume of distribution (Vss= 1.17 ± 0.18 l/kg), which suggests good tissue penetration, and a total body clearance (Cl) of 0.19 ± 0.042 l/kg.h, which is related to a long elimination half‐life (t1/2β= 4.74 ± 0.8 h and 5.47 ± 1.33 h i.v. and i.m. respectively). Marbofloxacin was rapidly absorbed after i.m. administration (MAT = 33.8 ± 14.2 min) and presented high bioavailability (F = 87.9 ± 6.0%). Pharmacokinetic parameters are not significantly different between both routes of administration (P>0.05). After marbofloxacin i.m. administration, no adverse reactions at the site of injection were observed. Serum CK activity levels 12 h after administration increased over 8‐fold (range 3–15) compared with pre‐injection levels, but this activity decreased to 3‐fold during the 24 h follow‐up period. Based on the value of surrogate markers to predict clinical success, Cmax/MIC ratio or AUC/MIC ratio, single daily marbofloxacin dose of 2 mg/kg bwt may not be effective in treating infections in horses caused by pathogens with an MIC ≥ 0.25 μg/ml. However, if we use a classical antimicrobial efficacy criteria, marbofloxacin can reach a high plasma peak concentration and maintain concentrations higher than MICs determined for marbofloxacin against most Gram‐negative veterinary pathogens throughout the administration period. Taking into account the fact that fluoroquinolones are considered to have a concentration‐dependent effect and a long postantibiotic effect against Gram‐negative bacteria, a dose of 2 mg/kg bwt every 24 h could be adequate for marbofloxacin in horses.
Deslorelin acetate (Ovuplant) therapy in cycling mares: effect of implant removal on FSH secretion and ovarian function
Authors: FARQUHAR V. J. , McCUE P. M. , CARNEVALE E. M. , NETT T. M. , SQUIRES E. L. 
Published: April 2007

SummaryFollowing induction of ovulation with deslorelin acetate (Ovuplant)1, gonadotrophin concentrations are reduced in the subsequent cycle, leading to increased interovulatory intervals in some mares. This study determined whether implant removal after 2 days prevented the decrease in gonadotrophin concentrations and follicular growth during the ensuing cycle. Twenty‐four mares were randomised equally into 3 groups.Group 1ovulated spontaneously,Groups 2and3received the deslorelin implant to induce ovulation. Two days after treatment, the implant was removed fromGroup 3.On Day 10 postovulation, FSH was lower (P = 0.009) inGroup 2, but not different betweenGroups 1and3.Follicular diameter on Day 14 was less (P<0.05) inGroup 2(19.0 ± 2.1 mm) than inGroups 1and3(36.6 ± 2.5 and 30.5 ± 2.0 mm, respectively). Interovulatory interval was longer (P<0.05) forGroup 2(25.8 ± 2.9 days) compared toGroups 1and3(18.5 ± 0.7 and 19.4 ± 0.3 days, respectively). Removal of the deslorelin implant eliminated the decreased FSH secretion and the increased interovulatory interval associated with implant administration. Therefore, it is recommended that the implant be removed after ovulation is detected to prevent the occurrence of a prolonged interovulatory interval.
Evaluation of nebulised hay dust suspensions (HDS) for the diagnosis and investigation of heaves. 3: Effect of fractionation of HDS
Authors: PIRIE R. S. , DIXON P. M. , McGORUM B. C. 
Published: April 2007

SummaryTo investigate the relative importance of inhaled particulates and soluble components in the response to inhaled hay dust suspension (HDS), heaves (previously termed chronic obstructive pulmonary disease; n = 7) and control (n = 6) horses were given inhalation challenges with whole and fractionated HDS. Fractionation was achieved by centrifugation to yield supernatant (SUP) and particulate debris. The particulates were then washed repeatedly in saline to produce a washed particulate (WP) fraction which comprised mainly fungal spores, and a wash fraction (WF) which comprised saline and soluble components washed from the surface of the particulates. Inhalation of HDS and SUP induced a significant airway neutrophilia in both groups, with the magnitude of the response being significantly greater in heaves horses. SUP induced significantly less airway neutrophilia than HDS in both groups, despite the endotoxin and protease content of HDS and SUP being comparable. WP and WF induced only a slight airway neutrophilia in heaves horses. However, a combined challenge with SUP and WP induced a neutrophilic response approaching the magnitude of that following HDS challenge, indicating that dust particulates contribute to the pulmonary recruitment of neutrophils in heaves. Consequently, inhalation challenge with HDS, which contains both particulates and soluble dust components, may be a more useful tool for the diagnosis and investigation of heaves than aqueous dust extracts, which contain only soluble components.
Biochemical development of subchondral bone from birth until age eleven months and the influence of physical activity
Authors: BRAMA P. A. J. , TeKOPPELE J. M. , BANK R. A. , BARNEVELD A. , van WEEREN P. R. 
Published: April 2007

SummarySubchondral bone provides structural support to the overlying articularcartilage, and plays an important role in osteochondral diseases. There is growing insight that the mechanical features of bone are related to the biochemistry of the collagen network and the mineral content. In the present study, part of the normal developmental process and the influence of physical activity on biochemical composition of subchondral bone was studied. Water content, calcium content and characteristics of the collagen network (collagen, hydroxylysine, lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) crosslinking) of subchondral bone were measured in newborn foals, 5‐month‐old foals (pasture‐grown and box‐confined) and 11‐month‐old foals at 2 differently loaded sites of the proximal articular surface of the first phalanx.During the first 5 monthspostpartum, water and hydroxylysine content decreased significantly while calcium and collagen content and the amount of HP and LP crosslinks increased significantly. The withholding of physical activity during this developmental phase affected the biochemical characteristics of subchondral bone only at the site that is loaded during physical exercise. At this site, calcium content and both HP and LP crosslink levels increased significantly less than in pasture‐raised animals. During development from 5–11 months, measured parameters remained essentially constant, except for water content, which decreased further.It is concluded that substantial changes, presumed to be largely exercise‐driven, take place during the normal process of development in the biochemical composition of equine subchondral bone. Normal development of subchondral bone is presumably important for the normal functional adaptation of this bone to the loading conditions it is subjected to and therefore essential to resist the future biomechanical challenges the horse will encounter during its athletic career. The findings from this study and the assumed important role of subchondral bone quality in the pathogenesis of osteochondral disease merit more attention to the role of the collagen network in subchondral bone.
Cultivation and characterisation of primary and subcultured equine keratinocytes
Authors: DAHM A. M. , de BRUIN A. , LIMAT A. , von TSCHARNER C. , WYDER M. , SUTER M. M. 
Published: April 2007

SummaryWe describe the establishment and characterisation of equine keratinocyte cultures with maintenance of a high proliferative capacity up to the second passage. Improved attachment and growth were obtained by seeding primary cells on equine feeder layers. Subcultured keratinocytes showed optimal growth when seeded on collagentype I.The proliferation rate of cells on this substrate exceeded that seen for cells seeded on equine feeder layers. By immunohistochemistry, epithelial origin and state of differentiation of the equine keratinocytes were determined. They expressed keratin and desmoplakin I/II, but lacked keratin 10. Electron microscopy revealed typical features of cultured keratinocytes. Purity of keratinocyte cultures was determined by vimentin staining. This is the first report on the establishment of equine keratinocytes derived from lip epithelium. It forms the basis to study equine keratinocyte biology and the pathogenesis of epidermal diseases. Since wound healing represents a severe problem in equine dermatology, our data may be essential for the establishment of new and improved therapy.
The use of magnetic motor evoked potentials in horses with cervical spinal cord disease
Authors: NOLLET H. , DEPREZ P. , van HAM L. , VERSCHOOTEN F. , VANDERSTRAETEN G. 
Published: April 2007

SummaryThe aim of this study was to investigate the use of magnetic motor evoked potentials as an ancillary diagnostic test in horses with cervical cord lesions.Transcranial magnetic stimulation was performed in 12 ataxic horses and the results of the evoked responses were compared to those found in normal horses. The latency and peak‐to‐peak amplitude of the potentials in the 12 ataxic horses were significantly different from those measured in normal horses. The configuration of the abnormal potentials was also polyphasic. Normalisation of the evoked potentials occurred in none of the horses, presented after a period of clinical improvement. These findings demonstrate that the technique is also able to detect lesions in horses with subtle clinical signs of incoordination.Magnetic transcranial stimulation is a valuable ancillary test to assess the integrity of the motortracts. The technique is painless and safe and shows good sensitivity to detect lesions along the descending motor pathways.
The effect of a pectin‐lecithin complex on prevention of gastric mucosal lesions induced by feed deprivation in ponies
Authors: MURRAY M. J. , GRADY T. C. 
Published: April 2007

SummaryThis study examined whether a product containing a pectin‐lecithin complex (Pronutrin)1could prevent gastric lesions induced in the equine gastric squamous epithelial mucosa using a protocol of intermittent feed deprivation that resulted in prolonged increased gastric acidity (Murray and Eichorn 1996). Eight ponies were used and served as theirown controls in 2 trials in which there were 72 h cumulative deprivation (alternating 24 h with no feed, then 24 h free choice hay), with a 4‐week interval between trials. Ponies were assigned randomly to receive either 250 g Pronutrin plus 200 g pelleted feed, or 450 g pelleted feed only. Ponies were conditioned to each treatment for 7 days and received Pronutrin and pellets oronly pellets once daily during the feed deprivation protocol. Gastroscopy was performed at the beginning and conclusion of the feed deprivation protocol. The endoscopist (M.J.M.) was blinded as to treatments, and lesion severity was scored on a scale of 0–5. Gastroscopy revealed normal‐appearing gastric mucosa at the beginning of feed deprivation, with the exception of 2 ponies which had focal squamous mucosal erosion and 1 pony with focal glandularmucosal erosion. After 72 h cumulative feed deprivation, each pony, except 1 pony in one of the trials, developed erosions or ulcers in the gastric squamous mucosa. There was no difference (P = 0.6) in the presence or severity of gastric lesions between treatments. Lesions did not develop in the gastric glandular mucosa as a result of the intermittent feed deprivation with either treatment. In this study, the pectin‐lecithin complex in Pronutrin failed to prevent lesions in the gastric squamous mucosa induced by intermittent feed deprivation.
Inhalation of organic dusts and lipopolysaccharide increases gelatinolytic matrix metalloproteinases (MMPs) in the lungs of heaves horses
Authors: NEVALAINEN M. , RAULO S. M. , BRAZIL T. J. , PIRIE R. S. , SORSA T. , McGORUM B. C. , MAISI P. 
Published: April 2007

SummaryWe report the effects of mouldy hay/straw exposure, inhaled hay dust suspension (HDS) and inhaled lipopolysaccharide (LPS) on bronchoalveolar lavage fluid (BALF) gelatinolytic matrix metalloproteinase (MMP) levels and degree of activation in healthy (n = 6) and heaves‐ (previously termed chronic obstructive pulmonary disease) affected (n = 6 or 7) horses. Gelatinolytic MMPs in BALF were quantified by zymography, and gelatinases were shown by Western immunoblotting to be MMP‐2 and MMP‐9. Hay/straw and HDS challenges increased BALF total gelatinolytic activity only in heaves horses, with the majority of gelatinolytic activity comprising pro‐ and active MMP‐9. The 5 h duration hay/straw challenge increased BALF gelatinolytic MMP activity in heaves horses at 5 and 24 h after the start of this challenge, with activity returning to baseline by Day 4. In contrast to hay/straw and HDS challenges, LPS inhalation increased BALF gelatinolytic MMP activity in both groups. For all challenges, absolute BALF neutrophil counts were highly significantly correlated (P<0.0001) with levels of proMMP‐9 and active MMP‐9, but not with levels of MMP‐2 (P>0.05). As gelatinolytic MMPs are pro‐inflammatory agents, they may contribute to lung dysfunction and tissue destruction in heaves horses exposed to airborne organic stable dusts.