bluuebunny/crossref_metadata_2025 huggingface dataset:
Equine carpal articular cartilage fibronectin distribution associated with training, joint location and cartilage deterioration
Authors: Murray Rachel C. , Janicke H. C. , Henson F. M. D. , Goodship A.
Published: April 2007

Processes involved in equine carpal osteochondral injury have not been established. In other species, fibronectin appears important in chondrocyte‐matrix interactions, and levels are increased in osteoarthritis. This investigation aimed to (a) describe fibronectin immunoreactivity in the middle carpal joint of 2‐year‐old Thoroughbreds, (b) determine topographical variations, (c) compare strenuously trained (Group 1) or gently exercised horses (Group 2) and (d) describe sites with early osteoarthritis.Group 1(n = 6) underwent a 19 week high intensity treadmill training programme.Group 2(n = 6) underwent 40 min walking until euthanasia. Dorsal and palmar sites on radial, intermediate and third carpal articular surfaces were prepared. Immunohistochemistry was performed using a biotin‐streptavidin/peroxidase method. Cross‐reactivity of rabbit antihuman fibronectin antiserum with equine fibronectin was confirmed using Western blotting. Results showed: (a) fibronectin was present primarily in pericellular and interterritorial matrix locations, (b) dorsal sites had zonal immunoreactivity compared to palmar sites, (c)Group 1dorsal radial carpal cartilage had increased superficial staining compared toGroup 2and (d) fibrillated cartilage showed increased intracellular and local matrical immunoreactivity (superficial zone). These findings suggest topographical and exercise‐related variations in fibronectin distribution, and indicate equine fibronectin is localised at sites of cartilage degeneration and released into the matrix by chondrocytes in the local area.
Postmortemfindings of gastric ulcers in Swedish horses older than age one year: a retrospective study of 3715 horses (1924–1996)
Authors: Sandin A. , Skidell J. , Häggström J. , Nilsson G.
Published: April 2007

The present study was performed to estimate retrospectively the prevalence of gastric ulceration in necropsied Swedish horses and to evaluate some potential risk factors. Horses (n = 3715) olderthan age one yearand necropsied 1924–1996 were included. Information about breed, gender, age, season of death, clinical signs of colic,Gasterophiluslarvae and documentation of diseases in different organs was recorded. Data on size, number and anatomical distribution of gastric ulcers were also obtained. The cold‐blooded horses and the Standardbreds were the 2 most dominating breeds in our material. Gastric ulcers/erosions were seen in 633 (17%) of the horses. The highest prevalence was found in Thoroughbreds (19%) and Standardbreds (19%), whereas only 7% of the cold‐blooded horses were affected. The cutaneous region along themargo plicatuswas the most commonly affected area (52%). Multiple ulcers were seen in 62% of the horses with gastric ulcers and concurrent ulcers in the oesophagus were reported in 6%. In the bivariate analysis, significant associations were found between gastric ulcers and signs of colic (P<0.001) and gender (P<0.001), as well as between concomitant bowel (P<0.001), liver (P<0.05) and oesophageal (P<0.01) lesions. Using a multivariate logistic regression model, only year of necropsy and breed were found significantly to influence the risk of gastric ulceration by decreasing the Log Likelihood test value. The present study shows clearly that gastric ulceration has been present in Swedish horses throughout the 20th century, which also may be the situation worldwide.
Immunity to equine influenza: relationship of vaccine‐induced antibody in young Thoroughbred racehorses to protection against field infection with influenza A/equine‐2 viruses (H3N8)
Authors: Newton J. R. , Townsend H. G. G. , Wood J. L. N. , Sinclair R. , Hannant D. , Mumford J. A.
Published: April 2007

Field outbreaks of influenza that occurred in vaccinated Thoroughbred racehorses in Newmarket in 1995 and 1996 were investigated by nucleoprotein ELISA and serology. Investigations showed that serum levels of vaccine‐induced single radial haemolysis (SRH) antibody correlated closely with protective immunity against equine influenza and were consistent with observations made in previous experimental studies using nebulised aerosol challenge. In the second part of this study, antibody levels stimulated by vaccination were investigated to examine probable protection in high risk groups, such as yearlings and horses in training. Results for yearlings correlated closely with experimentally derived antibody profiles described for several equine influenza vaccines. The horses in training had levels of antibody immediately prior to revaccination, which were higher than those measured in the yearlings. In conclusion, SRH antibody, used in the investigation of outbreaks and surveillance of post vaccination responses, was shown to correlate with and validate experimental vaccination and challenge models currently used in ponies in the licensing of modern vaccines. There may be benefit from serological monitoring of horses following vaccination through identification of susceptible periods to infection and demonstration of poor vaccine responders. This would allow appropriate and timely amendment of vaccination strategies to maximise protective immunity against influenza.
Influence of environmental and genetic factors on allergen‐specific immunoglobulin‐E levels in sera from Lipizzan horses
Authors: EDER C. , CURIK I. , BREM G. , CRAMERI R. , BODO I. , HABE F. , LAZARY S. , SÖLKNER J. , MARTI E.
Published: April 2007

To investigate whether allergen‐specific IgE production is influenced by environmental and genetic factors, IgE levels against 2 mould extracts (Alternaria alternata[Alt a] andAspergillus fumigatus[Asp f]) and against recombinant (r) rAlt a 1, rAsp f 7 and rAsp f 8 were determined by ELISA in sera from 448 Lipizzan horses living in 6 studfarms.

Statistical evaluation showed a significant effect of studfarm‐specific environment on IgE levels against the different allergens, but genetic factors also influenced allergen‐specific IgE production: an heritability of 0.33 was found for IgE levels against the 2 mould extracts and of 0.21 for rAsp f 8‐specific IgE. Heritability estimates for rAlt a 1‐ and rAsp f 7‐specific IgE were negligible.

Investigations for a possible association between Major Histocompatibility Complex (MHC) class I antigens and specific IgE levels were carried out. The most consistent significant association was found between the equine leucocyte antigen (ELA) A8 and undetectable IgE titres against rAsp f 7 and rAsp f 8. Significant ELA associations were also demonstrated between ELAA1 and higher specific IgE levels, between ELA A14 and lower IgE levels against the mould extracts and in one studfarm between ELA Be27 and lowerAspergillus‐specific IgE levels.
The mucosal humoral immune response of the horse to infective challenge and vaccination with Equine herpesvirus‐1 antigens
Authors: BREATHNACH C. C. , YEARGAN M. R. , SHEORAN A. S. , ALLEN G. P.
Published: April 2007

Equine herpesvirus‐1 (EHV‐1) remains a frequent cause of upper respiratory tract infection and abortion in horses worldwide. However, little is known about the local antibody response elicited in the upper airways of horses following exposure to EHV‐1. This study analysed the mucosal humoral immune response of weanling foals following experimental infection with virulent EHV‐1, or vaccination with either of 2 commercial vaccines. Twenty weanlings were assigned to 5 groups and were inoculated with, or vaccinated against, EHV‐1 following different regimens. Finally, all weanlings were simultaneously challenged intranasally with virulent EHV‐1 Army 183 (A183). Nasal wash and serum samples were collected at regular intervals until 13 weeks after final challenge. Nasal washes were assayed for EHV‐1‐specific equine IgGa, IgGb, IgG(T), IgA, IgM and total virus‐specific antibody using an indirect, quantitative ELISA. Total serum antibody responses were also monitored, and clinical signs of EHV‐disease were recorded for each individual.

Virus‐specific IgA dominated the mucosal antibody response elicited in weanlings inoculated with A183, being detectable at up to 3.1 μg/mg total IgA 13 weeks after challenge. Neither inactivated EHV‐1 administered i.m., nor attenuated EHV‐1 administered intranasally induced detectable mucosal antibodies. EHV‐1‐specific mucosal antibodies impeded EHV‐1 plaque formation in vitro. Such virus‐neutralising antibody probably contributes to a reduction of shedding of EHV‐1 from the respiratory tract of virus‐infected horses.
Neutrophil functions and serum IgG in growing foals
Authors: DEMMERS S. , JOHANNISSON A. , GRÖNDAHL G. , JENSEN‐WAERN M.
Published: April 2007

The aim of this study was to investigate the phagocytic and killing capacities as well as expression of CD18 of neutrophils obtained from healthy foals from birth to age 8 months. Blood was taken from 6 Standardbred foals at 7 time‐points between ages 2–56 days and thereafter once a month. For comparison, cells from 16 mature horses were evaluated. Neutrophil phagocytosis of yeast cells was assessed by flow cytometry after opsonisation with mature pooled serum, autologous serum or anti‐yeast IgG. The killing capacity of the neutrophils, as indicated by the oxidative burst, was monitored by chemiluminescence. Serum IgG concentration was measured by radial immunodiffusion. In addition to clinical examination, the amount of serum amyloid A and the total leucocyte count were used as markers for infection. The phagocytic ability was impaired until age 3 weeks, when autologous serum was used as opsonin. Killing capacity was also low initially but, from 3 months onwards, chemiluminescence values were equal to or higher than in mature horses. Serum IgG decreased from 10 g/l at 2 days to 5 g/l at 2 months and then increased gradually to 10 g/l at the end of the study. These findings may in part explain the increased susceptibility to bacterial infections in young horses.
Transforming growth factor beta concentrations and interferon gamma responses in cerebrospinal fluid of horses with equine protozoal myeloencephalitis
Authors: FURR M. , PONTZER C.
Published: April 2007

The following experiment was performed to test the hypothesis that transforming growth factor beta (TGF‐β) concentration varies in the cerebrospinal fluid and serum of horses with EPM and to determine if cerebrospinal fluid (CSF) alters the interferon‐gamma (IFN‐γ) rersponse of equine peripheral blood mononuclear cells (PBMCs). The concentration of transforming growth factor‐beta (TGF‐β2) was investigated in the serum and cerebrospinal fluid (CSF) of 18 horses (9 normal, 9 affected with equine protozoal myeloencephalitis [EPM]). The TGF‐β2 assay was validated in a group of 6 normal horses. Intra‐assay variability was 4.7%, and interassay variability was 10.7%. The slope of the curve of the unknown samples of various volumes demonstrated parallelism with a curve developed using equal volumes of assay kit standard. Assay of normal and EPM‐affected horses found that TGF‐β2 was present in both the serum and CSF of all animals. However, the concentration of TGF‐β2 in the CSF was less (P = 0.03) in EPM‐affected horses (144 pg/ml) than in normal horses (256 pg/ml). In addition, the effect of CSF from normal and EPM‐affected horses on the production of interferon‐gamma (IFN‐γ) by PHA‐P stimulated PBMCs from normal horses was investigated using a bioassay. It was found that CSF from normal and EPM‐affected horses enhanced IFN‐γ activity from PHA‐P stimulated peripheral blood mononuclear cells (P ≤ 0.05); however, the response to CSF from EPM‐affected horses was no different than the response to CSF from normal horses. Treatment of cells with anti‐TGF‐β2 monoclonal antibodies slightly increased the response when co‐incubated with CSF from normal horses, and slightly decreased it when co‐incubated with CSF from EPM‐affected horses. These differences, however, did not achieve statistical significance (P>0.05). Results of this study indicated that production of TGF‐β2 is altered in horses with EPM, and that CSF appears to contain substances which alter the inflammatory reaction to plant lectins. These findings confirm the immunomodulatory properties of CSF and suggest new techniques for future research regarding the pathophysiology of EPM.
Exercise alters the immune response to equine influenza virus and increases susceptibility to infection
Authors: FOLSOM R. W. , LITTLEFIELD‐CHABAUD M. A. , FRENCH D. D. , POURCIAU S. S. , MISTRIC L. , HOROHOV D. W.
Published: April 2007

Equine influenza virus remains a major health concern for the equine industry in spite of ongoing vaccination programmes. Previous work has shown that the immune system of horses can be affected by strenuous exercise. The possible adverse consequence of exercise‐induced alterations in lymphocyte responses measuredin vitrowas unknown. Here we demonstrate that subjecting vaccinated ponies to a 5 day strenuous exercise programme results in a significant suppression of their T cell‐mediated immune response to equine influenza virus as measured by decreased lymphoproliferation and gamma interferon production measuredin vitro.These same ponies also demonstrated increased susceptibility to influenza disease following a challenge exposure to the same strain of virus. Rested ponies that had received the same vaccine and challenge were completely protected from disease. Our results demonstrate that exercise‐induced suppression of the equine immune response to influenza virus can be associated with an increased susceptibility to disease.
Production of biologically active equine interleukin 12 through expression of p35, p40 and single chain IL‐12 in mammalian and baculovirus expression systems
Authors: McMONAGLE E. L. J. , TAYLOR S. , ZUILEKOM H. van , SANDERS L. , SCHOLTES N. , KEANIE L. J. , HOPKINS C. A. , LOGAN N. A. , BAIN D. , ARGYLE D. J. , ONIONS D. E. , SCHIJNS V. E. , NICOLSON L.
Published: April 2007

Interleukin‐12 (IL‐12) is a key cytokine in the development of cell‐mediated immune responses. Bioactive IL‐12 is a heterodimeric cytokine composed of disulphide linked p35 and p40 subunits. The aim of this study was to verify biologically activity of the products expressed from equine interleukin‐12 (IL‐12) p35 and p40 cDNAs and to establish whether equine IL‐12 could be expressed as a p35/p40 fusion polypeptide, as has been reported for IL‐12a of several mammalian species. We report production of equine IL‐12 through expression of p35 and p40 subunits in mammalian and insect cells and of a p35:p40 fusion polypeptide in mammalian cells. Conditioned medium recovered from cultures transiently transfected with constructs encoding equine p35 and p40 subunits or single chain IL‐12 enhanced IFN‐γ production in cells derived from equine lymph nodes. Preincubation of IFN‐γ inducing preparations with anti‐p40 monoclonal antibody resulted in a significant decrease in IFN‐γ induction capacity. Medium recovered from p35 and p40‐expressing baculovirus infected cultures enhanced target cell IFN‐γ production and proliferation. Experimental studies in mice and other animals have revealed a therapeutic benefit of IL‐12 in cancer, inflammatory and infectious disease and an adjuvant effect in prophylactic regimes. Production of a bioactive species‐specific IL‐12 is a first step towards an investigation of its potential application in equine species.
Immunoglobulin‐E‐bearing cells in skin biopsies of horses with insect bite hypersensitivity
Authors: HAEGEN A. van der , GRIOT‐WENK M. , WELLE M. , BUSATO A. , TSCHARNER C. von , ZURBRIGGEN A. , MARTI E.
Published: April 2007

The aim of the present study was to investigate, with immunohistochemistry andin situhybridisation, if immunoglobulin‐E (IgE) and mast cells are involved in the pathogenesis of insect bite hypersensitivity (IBH), an allergic dermatitis of horses. In tissue sections fixed in paraformaldehyde (PFA) for <24 h, significantly more IgE protein‐bearing cells were found in the dermis and epidermis of acute and chronic IBH lesions than in skin biopsies from healthy horses (medians = 466, 236 and 110 cells/mm2, respectively; P ≤ 0.01). More IgE‐mRNA positive (+) cells were observed in the dermis of acute IBH lesions than in the dermis of healthy skin (median = 2.8 vs. 0.0 cells/mm2; P ≤ 0.01). Significantly, more mast cells were detected with metachromatic (median = 160 vs. 62 cells/mm2; P ≤ 0.001) and tryptase‐specific stainings (median = 120 vs. 69 cells/mm2; P ≤ 0.001) in the dermis of acute IBH biopsies compared to healthy skin. No chymase+ mast cells were found in any skin biopsy. IBH lesions fixed in PFA for >24 h were compared to dermatomycosis (DM) lesions; IBH biopsies contained a similar number of IgE‐protein+ cells to DM biopsies (median = 249 vs. 192 cells/mm2; P = 0.08) but had significantly more IgE‐mRNA+, metachromatic and tryptase+ mast cells than DM biopsies. This study suggests an involvement of IgE‐mediated immune reactions in the pathogenesis of IBH as well as, sometimes, in dermatomycosis. Using double labelling, cells which expressed IgE protein and contained mast cell enzymes were detected.
Intravenous pentoxifylline does not enhance the pulmonary haemodynamic efficacy of frusemide in strenuously exercising Thoroughbred horses
Authors: MANOHAR M. , GOETZ T. E. , ROTHENBAUM P. , HUMPHREY S.
Published: April 2007

The present study was carried out to examine whether pentoxifylline administration to horses premedicated with frusemide would attenuate the exercise‐induced pulmonary arterial, capillary and venous hypertension to a greater extent than frusemide alone, thereby affecting the occurrence of exercise‐induced pulmonary haemorrhage (EIPH). Using established techniques, we determined right heart and pulmonary vascular pressures in 6 healthy, sound Thoroughbred horses at rest and during exercise performed at maximal heart rate at a workload of 14 m/s on 3.5% uphill grade in the control (no medications), frusemide (250 mg i.v., 4 h pre‐exercise)‐control, and the frusemide (250 mg i.v., 4 h pre‐exercise) + pentoxifylline (8.5 mg/kg bwt i.v., 15 min pre‐exercise) treatments. Sequence of the 3 treatments was randomised forevery horse and 7 days were allowed between them. In the control study, galloping at 14 m/s on 3.5% uphill grade elicited significant right atrial as well as pulmonary arterial, capillary and venous hypertension and all horses experienced EIPH as detected by the presence of fresh blood in the trachea on endoscopic examination. Frusemide administration was not attended by changes in heart rate at rest or during exercise. Although in the frusemide‐control experiments, a significant reduction in mean pulmonary arterial, capillary and wedge pressures was observed both at rest and during galloping at 14 m/s on 3.5% uphill grade, all horses still experienced EIPH. Pentoxifylline administration to standing horses premedicated with frusemide caused nervousness, muscular fasciculations, sweating and tachycardia. Although these symptoms had largely abated within 15 min, there were no significant changes in the right atrial or pulmonary vascular pressures. Exercise in the frusemide + pentoxifylline experiments also caused significant right atrial as well as pulmonary arterial, capillary and venous hypertension, but these data were not found to be significantly different from the frusemide‐control experiments. All horses in the frusemide + pentoxifylline experiments also experienced EIPH. In conclusion, our data indicate that pentoxifylline (8.5 mg/kg bwt i.v., 15 min pre‐exercise) is ineffective in modifying the pulmonary haemodynamic effects of frusemide in exercising horses. It should be noted, however, that we did not examine whether erythrocyte plasticity was altered by the administration of pentoxifylline. Since the intravascular force exerted onto the blood‐gas barrier of exercising horses premedicated with frusemide remained unaffected by pentoxifylline administration, it is concluded that concomitant pentoxifylline administration is unlikely to offer additional benefit to horses experiencing EIPH.
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

Based 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

We 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

Tendon 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

We 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

A 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

To 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

The 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

The 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

The 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

The 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

In 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

Equine 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

Zinc 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

The 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.
The radiographic development of the distal and proximal double contours of the equine navicular bone on dorsoproximal‐palmarodistal oblique (upright pedal) radiographs, from age 1 to 11 months
Authors: DIK K. J. , van den BELT A. J. M. , ENZERINK E. , van WEEREN P. R.
Published: April 2007

The aim of this study was to monitor the postnatal radiographic development of the proximal and distal double contours and the modelling of the shape of the proximal articular border. In mature horses, the proximal and distal contours of the navicular bone on dorsopalmar dorsoproximal‐palmarodistal oblique (upright pedal) radiographs are commonly visualised as 2 lines, one being the articular border and the second representing the border of the cortex facing the deep digital flexor tendon (flexor border). The shape of the proximal articular border may be concave, undulating, straight or convex in the mature animal. These shapes have been found to be hereditary and to constitute a predisposing factor in the pathogenesis of navicular disease. This predisposing role may result from a shape dependent distribution of the biomechanical forces exerted on this region. There is no agreement in the literature with respect to the moment when the navicular bone takes its mature radiographic appearance.

Upright pedal radiographs of the left front foot of 19 Dutch Warmblood foals were made at age 1 month and subsequently at intervals of 4 weeks, until the age of 11 months. The distal double contour developed soon after birth and the radiographic visibility of the articular border improved from ill‐defined at 1 or 2 months to clear manifestation at 3 or 4 months. The proximal double contour developed later. The articular border became usually visible at age 3 or 4 months and was clearly visible from age 9 months. The mature shape of the proximal articular border usually became recognisable from age 7 months and was always obvious between 9 and 11 months. This development was associated with a gradual modelling of the lateral and medial extremities of the navicular bone.

It was concluded that the navicular bone adopts its mature radiological appearance during the first yearpostpartum.Considering this early manifestation of the mature shape of the proximal articular border and its previously demonstrated inheritance, a force‐dependent development of this shape, as predicted by the trajectional theory/Wolffs law, is improbable. The predisposing role of this shape in the pathogenesis of navicular disease may therefore be explained by a shape‐dependent distribution of the biomechanical forces exerted on the navicular bone. Considering the potential application of these findings, from age 1 year shape determination enables identification of the individual and breed susceptibility for the development of navicular disease.
Acute thrombosis of limb arteries in horses with sepsis: five cases (1988–1998)
Authors: BRIANCEAU P. , DIVERS T. J.
Published: April 2007

A hypercoagulable condition and poor perfusion to distal extremities might occur during equine endotoxaemic or septic shock, which could cause thrombosis of limb arteries. In our review, thrombosis occurred in neonatal foals in association with Gram‐negative bacteraemia. In 3 olderfoals and adults, thrombosis was associated with inflammatory bowel disease, diarrhoea and toxaemia. All patients had been treated with broad‐spectrum antibiotics, nonsteroidal anti‐inflammatory drugs and i.v. crystalloid solutions. Two horses received i.v. hyperimmune plasma. A generalised coagulopathy was not suspected prior to clinical signs of distal limb necrosis, although thrombocytopenia occurred in 4 of the 5 cases at the time of, or shortly before, thrombosis. Thrombocytopenia, possibly due to platelets adherence to exposed subendothelial collagen, which induces contact activation of the intrinsic coagulation pathway, has been described in endotoxaemic horses and foals with gastrointestinal infectious or inflammatory diseases and disseminated intravascular coagulation.

Activation of procoagulants by endotoxins, decreased blood flow to the limbs and endothelial damage, may have been responsible for a hypercoagulable condition leading to thrombosis in these 5 cases. The 3 enterocolitis patients may have had increased risk of thrombosis because of loss of antithrombin III, haemoconcentration and acidosis.
Standing laparoscopic herniorrhaphy in stallions using cylindrical polypropylene mesh prosthesis
Authors: MARIËN T.
Published: April 2007

Standing laparoscopic herniorrhaphy was performed in 9 stallions. Appropriate analgesia was achieved by sedation with detomidine and local flank infiltration with mepivacaine. Three portal sites at the paralumbar fossa were used to perform the herniorrhaphy by means of triangulation. A cylindrical polypropylene mesh was inserted and fixated in the inguinal canal. Subsequent adhesion formation resulted in an obliterated inguinal canal within 2 weeks. This minimal invasive technique allowed us to perform a testis sparing herniorrhaphy in the standing horse.