bluuebunny/crossref_metadata_2025_split huggingface dataset:
Age‐related morphometry of equine calcified cartilage
Authors: MARTINELLI M. J. , EURELL J. , LES C. M. , FYHRIE D. , BENNETT D. 
Published: April 2007

SummaryAlthough there are many studies in the equine literature focused on articular diseases and the aetiology of osteoarthritis, few have concentrated on normal articular structures and how they change with age.The objective of this investigation was to study the thickness and morphology of the calcified cartilage layerof the distal metacarpus over a range of ages. A parasagittal slab of bone was sectioned from the region of sesamoid contact on the medial condyle of the metacarpi from 34 horses. The slab of bone was preserved, dehydrated and embedded, undecalcified, in methylmethacrylate and then stained with toluidine blue. Six repeatable fields of interest from the distal aspect of each metacarpus were digitised and examined to determine the morphology of the calcified cartilage layer. The thickness of the calcified cartilage, range 88–426 μm, was estimated using a method of integration.The results indicate an age‐related influence on the thickness of the calcified cartilage layer, generally increased in older horses. While this finding is significant, perhaps more importantly a positional relationship was also identified, indicating that pressures endured by different regions within a joint may dictate morphological development of the tissues. This study has begun to lay the groundwork to determine whether the calcified layer of the hyaline cartilage could be involved in the development of osteoarthritis.
Equine oocyte maturation with epidermal growth factor
Authors: LORENZO P. L. , LIU I. K. M. , CARNEIRO G. F. , CONLEY A. J. , ENDERS A. C. 
Published: April 2007

SummaryEpidermal growth factor (EGF) has been shown to have a positive effect during oocytein vitromaturation in several species. This study was performed to establish the capacity of equine oocytes to undergo nuclear maturation in the presence of EGF and to localise its receptor in the equine ovary by immunohistochemical methods. Oocytes were obtained by aspiration and subsequent scraping from equine follicles (15–25 mm diameter) and cultured in 3 different treatment groups for 36 h: control Group (modified TCM 199 with 0.003% BSA), EGF Group (TCM‐199 supplemented with 50 ng/ml EGF) and EMS Group (TCM 199 supplemented with 10% v/v oestrous mare serum). Each group was divided further into 3 treatments with tyrphostin A‐47, a specific tyrosine kinase inhibitor, at 0, 10−4and 10−6mmol/l. Maturation was determined as the percentage of oocytes reaching metaphase II stage at the end of the culture period. Immunohistochemical detection of EGF‐receptor (EGFR) was performed using a streptoavidinbiotin method. The recovery rate and oocyte retrieval were 84.6% (recovered oocytes/follicles aspirated) and 6.55 (oocytes/mare), respectively. Treatment with EGF significantly (P<0.05) increased the incidence of metaphase II stage compared with the control group (69.4 vs. 26.9% in controls, respectively). The specific‐tyrosine kinase inhibitor A‐47 was effective in suppressing EGF‐effect on EGF‐cultured oocytes; no significant differences were observed in EMS‐supplemented oocytes when cultured with A‐47. EGF‐receptor was localised in follicles, with localisation being more prominent in the cumulus than in mural granulosa cells. This finding, together with the increase of oocyte nuclear maturation rate when using EGF in culture media and the inhibition of maturation by tyrphostin A‐47, suggests a physiological role for EGF in the regulation of equine oocyte maturation. The results should help successful development of assisted reproductive technology in the horse.
Interleukin‐4 and interferon‐gamma gene expression in summer pasture‐associated obstructive pulmonary disease affected horses
Authors: BEADLE R. E. , HOROHOV D. W. , GAUNT S. D. 
Published: April 2007

SummaryWe hypothesised that horses affected with summer pasture‐associated obstructive pulmonary disease (SPAOPD) react to an allergen or allergens in their summer environment that is either absent or present at lower levels in their winter environment; and that such allergencs stimulate SPAOPD‐affected horses to produce a different T helper lymphocyte cytokine profile from that of control horses. The primary objective of this study was to determine the cytokine mRNA profile of T helper lymphocytes obtained from summer pasture‐associated obstructive pulmonary disease (SPAOPD) affected horses when 1) the horses were showing signs of disease (summer) and 2) they were in clinical remission (winter). A further objective was to determine the differences between cytokine mRNA T helper lymphocyte profiles of control and affected horses in the summer and winterseasons. Interleukin 4 (IL‐4) and interferon‐gamma (IFN‐γ) mRNA expression levels were increased in bronchoalveolar lavage fluid (BALF) and peripheral blood mononuclear cell (PBMC) samples of affected horses during disease expression. No significant amounts of IL‐5 mRNA were detected in any of the samples. These results suggest that there is an allergic component to SPAOPD of horses and that appropriate manipulation of the immune system could offer hope for treatment and prevention of the disease in the future. Further research studies will be needed to determine the most appropriate treatments to use to alter the antigen‐stimulated cytokine profile being expressed by SPAOPD‐affected horses or to alter the effects that these cytokines produce.
Changes in physiological parameters in overtrained Standardbred racehorses
Authors: HAMLIN M. J. , SHEARMAN J. P. , HOPKINS W. G. 
Published: April 2007

SummaryVarious changes in physiological parameters are associated with overtraining, which can be a serious problem for human and equine athletes. A 34 week longitudinal study was conducted to investigate the effects of an acute training overload on physiological parameters in 10 Standardbred racehorses. After 24 weeks of training, horses received 8 weeks of increased workload, followed by 2 weeks recovery. Horses performed a 2400 m time trial and a progressive submaximal exercise test on alternate weeks. By the end of the heavy training period, the average time for the final 1200 m of the time trial increased by 4.0% (95% probable range of true value 1.7–5.8) and peak velocity decreased by 6.9% (4.7–8.9), indicating that overtraining had occurred. Acute overtraining coincided with an increase in blood lactate concentration after the time trial and submaximal test. There were also substantial decreases in bodyweight, plasma cortisol concentration and packed cell volume after the time trial, and in the velocity at a heart rate of 200/min (V200). Parameters that showed no clear‐cut change with overtraining included maximal and recovery heart rate, basal plasma cortisol, plasma and red cell volume, and markers of skeletal damage (plasma concentrations of creatine kinase and aspartate aminotransferase). Bodyweight, V200, postexercise blood lactate and plasma cortisol concentrations may all be useful for detecting acute overtraining in equine athletes.
Characterisation of reconstituted equine cartilage formedin vitro
Authors: SUN Y. , CHEN H. , KANDEL R. , HURTIG M. 
Published: April 2007

SummaryLesions in cartilage of equine weight bearing joints commonly result in lameness. Cell‐based resurfacing techniques are currently being developed for human and veterinary applications. Biopsies of stifle joint cartilage (1 g) were harvested aseptically and chondrocytes were isolated by sequential enzyme digestion. The cells were grownin vitroon filterinserts. Analysis of cultures 8 weeks latershowed that the cells had accumulated extracellular matrix and formed a continuous layer of cartilagenous tissue as determined histologically. The cells maintained their phenotype as they synthesisedtype IIcollagen and proteoglycans similar in size to those synthesised by chondrocytes in native cartilage, but this reconstituted tissue had more sulphated glycosaminoglycan and lower collagen content than native cartilage. This experiment tests the feasibility of growing equine cartilagenous tissuein vitro.This tissue may be useful in the management of chondral injuries in the horse in a scenario where the patient donates cells, the cells are propagated under laboratory conditions and the resulting tissue becomes the therapeutic agent.
Pharmacokinetics of marbofloxacin in horses
Authors: BOUSQUET‐MELOU A. , BERNARD S. , SCHNEIDER M. , TOUTAIN P. L. 
Published: April 2007

SummaryMarbofloxacin is a fluoroquinolone antibiotic expected to be effective in the treatment of infections involving Gram‐negative and some Gram‐positive bacteria in horses. In order to design a rational dosage regimen for the substance in horses, the pharmacokinetic properties of marbofloxacin were investigated in 6 horses after i.v., subcutaneous and oral administration of a single dose of 2 mg/kg bwt and the minimal inhibitory concentrations (MIC) assessed forbacteria isolated from equine infectious pathologies. The clearance of marbofloxacin was mean ± s.d. 0.25 ± 0.05 l/kg/h and the terminal half‐life 7.56 ± 1.99 h. The marbofloxacin absolute bioavailabilities after subcutaneous and oral administration were 98 ± 11% and 62 ± 8%, respectively. The MIC required to inhibit 90% of isolates (MIC90) was 0.027 μg/ml for enterobacteriaceae and 0.21 μg/ml forStaphylococcus aureus.The values of surrogate markers of antimicrobial efficacy (AUIC, Cmax/MIC ratio, time above MIC90) were calculated and the marbofloxacin concentration profiles simulated for repeated administrations. These data were used to determine rational dosage regimens for target bacteria. Considering the breakpoint values of efficacy indices for fluoroquinolones, a marbofloxacin dosage regimen of 2 mg/kg bwt/24 h by i.v., subcutaneous or oral routes was more appropriate for enterobacteriaceae than forS. aureus.
Molecular characterisation of carbohydrate digestion and absorption in equine small intestine
Authors: DYER J. , MEREDIZ E. FERNANDEZ‐CASTAÑO , SALMON K. S. H. , PROUDMAN C. J. , EDWARDS G. B. , SHIRAZI‐BEECHEY S. P. 
Published: April 2007

SummaryDietary carbohydrates, when digested and absorbed in the small intestine of the horse, provide a substantial fraction of metabolisable energy. However, if levels in diets exceed the capacity of the equine small intestine to digest and absorb them, they reach the hindgut, cause alterations in microbial populations and the metabolite products and predispose the horse to gastrointestinal diseases. We set out to determine, at the molecular level, the mechanisms, properties and the site of expression of carbohydrate digestive and absorptive functions of the equine small intestinal brush‐border membrane. We have demonstrated that the disaccharidases sucrase, lactase and maltase are expressed diversely along the length of the intestine and D‐glucose is transported across the equine intestinal brush‐border membrane by a high affinity, low capacity, Na+/glucose cotransporter type 1 isoform (SGLT1). The highest rate of transport is in duodenum > jejunum > ileum. We have cloned and sequenced the cDNA encoding equine SGLT1 and alignment with SGLT1 of other species indicates 85–89% homology at the nucleotide and 84–87% identity at the amino acid levels. We have shown that there is a good correlation between levels of functional SGLT1 protein and SGLT1 mRNA abundance along the length of the small intestine. This indicates that the major site of glucose absorption in horses maintained on conventional grass‐based diets is in the proximal intestine, and the expression of equine intestinal SGLT1 along the proximal to distal axis of the intestine is regulated at the level of mRNA abundance. The data presented in this paper are the first to provide information on the capacity of the equine intestine to digest and absorb soluble carbohydrates and has implications for a better feed management, pharmaceutical intervention and for dietary supplementation in horses following intestinal resection.
Detection of cold‐adapted vaccine‐strain influenza virus using two commercial assays
Authors: ADAM E. N. , MORLEY P. S. , CHMIELEWSKI K. E. , CARMAN J. , GONZALES G. 
Published: April 2007

SummaryBecause of the contagious nature of influenza virus it is necessary to identify infected individuals after the virus is introduced into a population. The aim of this study was to characterise influenza virus detection with commercially available assays after intranasal vaccinating horses with cold‐adapted influenza virus. Seven horses were vaccinated and placed with 3 unvaccinated horses. Nasal secretion samples were evaluated using 2 antigen detection assays. All 10 horses were positive in the Flu OIA assay during the study period, but only one horse was positive on one sample using the Directigen Flu A assay. Horses were most likely to be positive during the first 3 days following vaccination, and several horses were intermittently positive for several days after this. Obtaining positive test results from nonvaccinated, incontact horses suggests they became infected with vaccine‐strain virus that was shed by vaccinated horses. These results are important for the correct interpretation of influenza antigen detection tests in situations when this modified‐live intranasal vaccine has been used.
Evaluation of a combined laser Doppler flowmetry and iontophoresis technique for the assessment of equine cutaneous microvascular function
Authors: McGORUM B. C. , MILNE A. J. , TREMAINE W. H. , STURGEON B. P. R. , McLAREN M. , KHAN F. 
Published: April 2007

SummaryA combined laser Doppler flowmetry and iontophoresis (LDFI) technique, used routinely to assess human microvascular function, was evaluated as a noninvasive technique for assessment of equine microvascular function, to facilitate the study of diseases such as laminitis. Baseline and vasoactive agonist‐induced (acetylcholine and nitroprusside) microvascular flux was quantified at 2 sites (on the dorsal pastern adjacent to the coronary band and over the gluteals) in 6 clinically normal horses on 5 or 6 separate occasions under standardised conditions. Both agonists significantly increased microvascular flux. Skin pigmentation significantly attenuated the baseline flux, but not the magnitude of the agonist‐mediated vasodilatory response. While LDFI was simple to perform, its value as a clinical and research tool for assessing the equine cutaneous microcirculation is limited by its poor reliability, as indicated by the marked intra‐ and intersubject variability in baseline and agonist‐mediated microvascularflux.
Plasma adrenocorticotropin (ACTH) concentrations and clinical response in horses treated for equine Cushing's disease with cyproheptadine or pergolide
Authors: PERKINS G. A. , LAMB S. , ERB H. N. , SCHANBACHER B. , NYDAM D. V. , DIVERS T. J. 
Published: April 2007

SummaryPlasma ACTH levels have been variable in horses with a positive clinical response for therapy for equine Cushing's Disease (ECD). Therefore, our purpose was to determine the value of monitoring plasma adrenocorticotropin (ACTH) levels during treatment of equine Cushing's disease (ECD) with either cyproheptadine (n = 32) or pergolide (n = 10). First, we validated the chemiluminescent ACTH assay (specificity, precision, accuracy, intra‐assay and interassay variations) and tested methods of handling the whole blood from the time of collection to when the ACTH was assayed. The sensitivity and specificity of high plasma ACTH levels for detecting ECD was determined in a retrospective study on hospitalised horses (n = 68). Surveys were sent to veterinarians who submitted equine ACTH levels that were high initially and had at least 2 ACTH samples to determine the value of monitoring ACTH levels during therapy of ECD.The ACTH chemiluminescent assay was valid. The ACTH was stable when whole blood was collected and held in plastic tubes for 8h before separating the plasma. The sensitivity and specificity of plasma ACTH levels for detecting ECD were 84% (n = 19, 95% CI 60, 97) and 78% (n = 49, 95% CI 63, 88), respectively. Treated horses generally showed a decrease in plasma ACTH. Plasma ACTH levels may be helpful when monitoring therapy of ECD, although improvement in clinical signs should be considered most important. There were no differences between cyproheptadine and pergolide in terms of improvements in any of the clinical signs.
Calcium homeostasis and intact plasma parathyroid hormone during exercise and training in young Standardbred horses
Authors: VERVUERT I. , COENEN M. , WEDEMEYER U. , CHROBOK C. , HARMEYER J. , SPORLEDER H. ‐P. 
Published: April 2007

SummaryPhysical exercise is known to affect calcium homeostasis in horses, but there is little information on the hormonal regulation of calcium metabolism during exercise. In order to evaluate the effects of exercise and training on calcium homeostasis and intact plasma parathyroid hormone, 7 untrained Standardbred horses were studied in a 6 week training programme. These horses were accustomed to running on the treadmill 3 weeks before onset of training and were exercised on a high‐speed treadmill with an initial incremental standardised exercise test (SET 1: 6 incremental steps of 5 min duration each; first step 5 m/s, increase 1 m/s). SET 1 was followed by a lactate‐guided training programme (6 weeks in total) with 2 types of exercise in alternating order with a day of rest after each work day: high‐speed exercise (HSE) of 15 min duration, starting at VLa4, continuous increase in speed every 60 s by 0.3 m/s (14 incremental steps); and low‐speed exercise (LSE) at a constant velocity at VLa2.5, duration ˜60–90 min. The whole training programme consisted of 8 HSE and 8 LSE sessions. HSE and LSE were calculated to require the same energy expenditure. A final SET (SET 2) finished the training programme. Blood samples for lactate, plasma total calcium [Ca], blood ionised calcium [Ca2+], blood pH, plasma inorganic phosphorus [Pi] and plasma intact parathyroid hormone [PTH] were collected before, during and after SETs 1 and 2, before and after the first and eighth HSE and LSE. During SETs 1 and 2, HSEs 1 and 8 there was a decrease in ionised Ca2+and pH and a rise in lactate, intact PTH and Pi. LSEs 1 and 8 resulted in an increase in pH, whereas lactate, ionised Ca2+, total Ca, Piand intact PTH were not affected. No changes in calcium metabolism were detected during training. Results of this study suggest that intact PTH is a mediator in counter‐regulation of exercise‐induced hypocalcaemia.
Analysis of strain and stress in the equine hoof capsule using finite element methods: comparison with principal strains recorded in vivo
Authors: THOMASON J. J. , McCLINCHEY H. L. , JOFRIET J. C. 
Published: April 2007

SummaryFinite‐element (FE) methods have great potential in equine biomechanics in evaluating mechanical stresses and strains in tissues deep within the hoof. In this study, we critically assessed that potential by comparing results of FE analyses of capsular strain with in vivo data. Nine FE models were developed, corresponding to the shape of hooves for which in vivo principal strain data are available. Each model had the wall, laminarjunction, sole and distal phalanx (PIII). In a first loading condition (LC1), force is distributed uniformly to the bearing surface of the wall to determine reaction forces and moment on PIII. These reaction forces were subsequently applied to PIII in loading condition 2 (LC2) to simulate loading via the skeleton. Magnitude of the force resultant was equivalent to the vertical force on the hoof at midstance. Principal compressive strains ε2 were calculated at the locations of 5 rosette gauges on the real hooves and are compared with the in vivo strains at midstance.FE strains were from 16 to 221% of comparable in vivo values, averaging 104%. All models in this, and reports by other workers, show predominance of stress and strain at the toe to a greater extent than in the real hoof. The primary conclusion is that FE modelling of strain in the hoof capsule or deeper tissues of individual horses should not be attempted without corroborating experimental data.
Dynamics in serum of the inflammatory markers serum amyloid A (SAA), haptoglobin, fibrinogen and α2‐globulins during induced noninfectious arthritis in the horse
Authors: HULTÉN C. , GRÖNLUND U. , HIRVONEN J. , TULAMO R. ‐M. , SUOMINEN M. M. , MARHAUG G. , FORSBERG M. 
Published: April 2007

SummaryDespite the importance of noninfectious joint diseases in equine medicine, little is known about the acute phase response which may be elicited if the local inflammatory process of noninfectious arthritis is sufficiently strong, Therefore the aim of this study was to monitor the systemic inflammatory response during experimentally‐induced noninfectious arthritis by studying the dynamics in serum of the acute phase proteins serum amyloid A (SAA), haptoglobin, fibrinogen and α2‐globulins. Twenty‐four Standardbred horses, age 3–7 years, found healthy on thorough clinical, radiological, haematological and serum biochemical examination, were injected aseptically into the right midcarpal joint with amphotericin B. Blood samples were drawn before induction of arthritis (0 h), and at 8, 16, 24, 36 and 48 h postinduction and then on Days 3, 4, 5 and 15 postinduction. All horses developed lameness with joint effusion and joint heat as well as increased respiratory rate, heart rate and body temperature. The lameness started to decline after 24–36 h and, in most animals, systemic signs disappeared on Day 2 postinjection. The concentration of the acute phase proteins increased following induction of arthritis. The SAA concentrations were higher than baseline concentrations from 16 h postinduction and were maximal at 36–48 h (227 times baseline concentration). The haptoglobin concentrations were higher than baseline concentrations from 24 h and were maximal at 48–96 h (1.14 times baseline concentration). The maximal concentrations of fibrinogen were seen between 36–72 h postinjection and increased on average 0.87 times from baseline concentrations. The fibrinogen concentrations were higher than baseline concentrations from 24 h postinjection. α2‐globulins concentrations showed a minor in crease and increased 0.55 times from baseline concentrations. The markers had returned to baseline concentrations by Day 15.Our results demonstrate that amphotericin B‐induced arthritis in a single joint gives rise to a systemic acute phase response measurable as increased concentrations in serum SAA, haptoglobin, fibrinogen and α2‐globulins during the first 2 weeks of the condition and, thereby, that such an increase need not be indicative of infectious arthritis. Further research should be aimed at determining whether chronic noninfectious arthritis in the horse gives rise to increased acute phase protein concentrations in serum.