bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of an Ovarian Sclerosing Stromal Tumor Presenting as Vaginal Bleeding in a 7-Month-Old
Authors: Hall Odette R. , Pascasio Judy M. , Morrissette Jennifer J. , Newton Christopher , Schwartz Marshall Z. , de Chadarévian Jean-Pierre
Published: September 2008

This communication describes the histological, immunohistochemical, ultrastructural, and cytogenetic study of an ovarian sclerosing stromal tumor resected from a 7-month-old girl who presented with vaginal bleeding. The tumor is very rare, its pathogenesis is not clear, and its hormonal activity has been subject to debate. In addition, it has been rarely seen in children and never in infants, with the youngest patient reported being 10 years of age. Histological study of the tumor showed a process of multinodular asynchronous growth followed by gradual loss of cells, hyalinization, and eventual transformation into corpora albicantia–like structures, thus indicating that the process may be more akin to an ovarian nodular follicular hyperplasia than to a classical neoplasm. The study also documented an elevated proliferative MIB-1 index in the process, which had not been investigated in earlier reports, and illustrated the immunohistochemical reactivity of some of its stromal cells to progesterone receptors.
Polyneuropathy of Finnish horses characterised by inflammatory demyelination and intracisternal Schwann cell inclusions
Authors: HAHN C. N. , MATIASEK K. , SYRJA P. , JOKINEN T. S. , MACINTYRE N. , TULAMO R. M.
Published: September 2008

Reasons for performing study: A neurological disorder characterised by pelvic limb metatarsophalangeal joint extensor paresis has been observed in numerous horses in Scandinavia for the last decade. Very little has been formally reported and there have been no detailed assessments of the neurological signs or neuropathological lesions.

Objectives: To describe the epidemiological and pathological features of an outbreak of ‘Scandinavian knuckling syndrome’ in a riding stable in southern Finland.

Methods: Clinical neurological examination of 4 cases and neuropathological assessment of tissues of one case were performed.

Results: Eleven out of 17 horses fed on ryegrass from a common source showed progressive clinical signs of metatarsophalangeal extensor paresis necessitating euthanasia of 7 horses. Nervous system lesions in one horse consisted of a novel demyelinating, mildly inflammatory peripheral neuropathy, with BiP/GRP positive rough endoplasmatic reticulum Schwann cell inclusions.

Conclusions: The clinical signs and lesions documented differ from any previously described equine polyneuropathy and suggest a primary Schwann cell lesion.

Potential relevance: The classification of this disease as a novel demyelinating polyneuropathy may assist focused epidemiological investigations.
Arthroscopic injection of corticosteroids into the fibrous tissue of subchondral cystic lesions of the medial femoral condyle in horses: A retrospective study of 52 cases (2001–2006)
Authors: Wallis T. W. , Goodrich L. R. , Mcilwraith C. W. , Frisbie D. D. , Hendrickson D. A. , Trotter G. W. , Baxter G. M. , Kawcak C. E.
Published: September 2008

Reasons for performing study: There are no published results of subchondral cystic lesions (SCLs) in the medial femoral condyle (MFC) treated with arthroscopic injection of corticosteroids into the lining of the cyst.

Objectives: 1) To determine the success rate for treatment of SCLs in the MFC with arthroscopic injection of the fibrous tissue of the cyst with corticosteroids. 2) To identify any factors that may predict outcome.

Hypotheses: Injection of the fibrous tissue of SCLs of the MFC with corticosteroids utilising arthroscopic guidance yields a similar or higher chance for intended performance than does arthroscopic debridement as previously reported; this technique will be effective for treating SCLs in older horses.

Methods: Horses with clinical and radiographic evidence of a SCL in the MFC were injected with corticosteroids under arthroscopic guidance, and case records and radiographs were reviewed retrospectively. A telephone survey of referring veterinarians, owners and trainers was conducted.

Results: Thirty‐five of 52 (67%) cases were classified as successful involving 73 SCLs of which 56 (77%) were classified as successful. There was no significant association between age group (age ≤3 years vs. >3 years) and outcome, or cyst configuration and outcome. Significantly more unilateral SCLs (28/31 [90%] SCLs) were classified as successful than bilateral (28/42: 67%). There were significant differences in outcome based on the surgeon operating the case and an association between pre‐existing radiographic findings of osteophytes and negative outcome.

Conclusions: Injection of SCLs utilising arthroscopic guidance is an effective alternative method of surgical treatment of SCL.

Potential relevance: This technique offers a similar chance of success as has been reported with debridement and may allow for a shorter period of convalescence. If unsuccessful, the option remains to debride the cyst in a second surgery.
Risk factors for epiploic foramen entrapment colic: An international study
Authors: ARCHER D. C. , PINCHBECK G. L. , FRENCH N. P. , PROUDMAN C. J.
Published: September 2008

Reasons for performing study: Epiploic foramen entrapment (EFE) is one of the most common causes of small intestinal strangulation in the horse. Identification of risk factors would generate hypotheses about causation and may suggest preventive strategies.

Hypothesis: Horses exhibiting certain behavioural patterns and those exposed to particular management practices are at increased risk of EFE.

Methods: A matched case‐control study was conducted on EFE cases admitted to hospitals in the UK, Ireland and USA. Data on 109 cases and 310 control horses were obtained by telephone questionnaire and conditional logistic regression was used to identify associations between horse‐ and management‐level variables and the risk of EFE.

Results: Crib‐biting/windsucking behaviour was strongly associated with increased risk of EFE (OR 67.3, 95% CI 15.3–296.5). A history of colic in the previous 12 months (OR 4.4, 95% CI 1.5–12.7) and horses of greater height (OR/cm 1.05, 95% CI 1.01‐1.08) were also at increased risk. The person(s) responsible for horses' daily care (nonowner/relative/spouse OR 5.5, 95% CI 2.3–13.3) and a number of behavioural features, including response to a stimulus causing fright (easily frightened OR 0.4, 95% CI 0.1‐1.0) or excitement (sweats up easily/occasionally OR 0.3, 95% CI 0.1‐0.8), reaction to their surroundings (inquisitive OR 0.4, 95% CI 0.2‐0.8) and feeding behaviour when stressed (goes off food in full/part OR 0.3, 95% CI 0.1‐1.0) were also associated with altered risk of EFE.

Conclusions: The association between horses of greater height and those with a previous history of colic and increased risk of EFE suggests that some horses may be inherently predisposed to EFE. Furthermore, a behavioural pattern has been characterised that is common to horses at increased risk of EFE. Further research is required to investigate the causal pathway linking behavioural traits with gastrointestinal dysfunction and to determine whether behavioural modification reduces the risk of EFE.

Potential relevance: The findings of the present study have relevance to horses in the UK, Ireland and USA.
The effect of metformin on measurements of insulin sensitivity and β cell response in 18 horses and ponies with insulin resistance
Authors: Durham A. E. , Rendle D. I. , Newton J. R.
Published: September 2008

Reasons for performing study: Laminitis in equids is a very common debilitating disease, and insulin resistance (IR) and hyperinsulinaemia are increasingly recognised as important predisposing factors. Pharmacological modification of IR and hyperinsulinaemia might reduce the risk of laminitis.

Hypothesis: Metformin, a drug commonly prescribed for treatment of human IR, may also decrease IR in equids.

Methods: Eighteen horses and ponies with IR and recurrent laminitis were treated with 15 mg/kg bwt metforminper osq. 12 h. Each animal served as its own control by comparing pre‐ and post treatment proxies for IR, insulin sensitivity (IS) and pancreatic β cell function while controlling for possible dietary and managemental influences on IR.

Results: Evidence of significantly improved IS and decreased pancreatic β cell secretion was found following metformin treatment. The magnitude of effect was greater at earlier resampling (6–14 days) than at later times (23–220 days). Apparent subjective clinical benefits were good but less favourable than effects on IR.

Conclusions: Metformin is safe and appears to increase IS in equids.

Potential relevance: Metformin may be indicated as a treatment for IR in equids. Further studies are required to define appropriate selection of subjects warranting therapy, dosing schedule and pharmacokinetics.
Long‐term study of partial arytenoidectomy with primary mucosal closure in 76 Thoroughbred racehorses (1992–2006)
Authors: PARENTE E. J. , TULLENERS E. P. , SOUTHWOOD L. L.
Published: September 2008

Reasons for performing study: The effectiveness and best method to perform a partial arytenoidectomy in racehorses is unclear. This study was performed to evaluate the success of and complications that can occur after a unilateral partial arytenoidectomy with primary mucosal closure in Thoroughbred racehorses.

Hypothesis: Partial arytenoidectomy is an effective surgical procedure to return Thoroughbred racehorses, afflicted by arytenoid chondropathy or a failed laryngoplasty, to preoperative levels of performance.

Methods: Seventy‐six Thoroughbred racehorses admitted to the New Bolton Centre between 1992 and 2006 were assessed. Information was obtained from the medical records about the horse, laryngeal abnormalities, surgery and other findings during hospitalisation. Racing information was evaluated relative to those independent variables by an analysis of variance with a level of significance of P<0.05.

Results: Arytenoid chondropathy was the presenting complaint in 54 horses and failed laryngoplasty in 22 horses. Thirteen horses (17%) underwent a second surgery for laser excision of intralaryngeal granulation tissue at the arytenoidectomy site. Seventy‐three horses were discharged from the hospital and racing outcome was evaluated. Sixty horses (82%) raced after surgery and 46 horses (63%) raced 5 or more times after surgery. The median time from surgery to the first start was 6 months. The average earnings/start was not significantly different before and after surgery. There was no association between earnings after surgery and age, gender, location of lesion, type of lesion, duration of tracheal intubation or undergoing a second surgery.

Conclusions and potential relevance: A Thoroughbred racehorse is likely to race after a unilateral partial arytenoidectomy with primary mucosal closure and return to a preoperative level of performance.
Penile and preputial squamous cell carcinoma in the horse: A retrospective study of treatment of 77 affected horses
Authors: van den TOP J. G. B. , DE HEER N. , KLEIN W. R. , ENSINK J. M.
Published: September 2008

Reasons for performing study: The most common penile and preputial neoplasm in the horse is the squamous cell carcinoma (SCC), but no large surveys of treatment and effects of the grade of the tumour, based on the degree of differentiation, on outcome of affected horses are available.

Objectives: Analysis of treatment of male horses affected with SCC of the external genitalia and long‐term results of treatment.

Methods: Seventy‐seven cases of SCC were evaluated. Data recorded included treatment, outcome, post operative histopathology and retrospective tumour grading.

Results: Treatments included: cryosurgery, excision, partial phallectomy, partial phallectomy and sheath ablation, anden blocpenile and preputial resection with penile retroversion and removal of inguinal lymph nodes. The incidence of recurrence after partial phallectomy was 25.6% (10/39) and following incomplete removal was 17.9% (7/39). The incidence of recurrence afteren blocresection with retroversion was 12.5% (1/8). In horses with confirmed inguinal lymph node metastasis, the incidence of recurrence was 25.0% (1/4). Poorly differentiated SCCs were more likely to metastasise than well differentiated SCCs, and there was a greater chance that the treatment would be unsuccessful. The success of treatment, complete removal and in preventing recurrence of the tumour, of male horses with SCC of the external genitalia was 55.7%.

Conclusions: Horses that receive only partial phallectomy for treatment for SCC of the external genitalia have a high incidence of recurrence in contrast to horses that receive anen blocresection. Tumour grading of SCC can help predict prognosis and guide selection of treatment.
A retrospective study of artificial insemination of 251 mares using chilled and fixed time frozen‐thawed semen
Authors: CROWE C. A. M. , RAVENHILL P. J. , HEPBURN R. J. , SHEPHERD C. H.
Published: September 2008

Reasons for performing study: Historically, artificial insemination (AI) using frozen semen has been perceived to have poorer success rates and be more labour intensive than using chilled semen. A retrospective study was therefore conducted to compare the conception rate achieved by AI between chilled and frozen semen, using fixed time insemination protocols over 2 breeding seasons.

Hypothesis: Artificial insemination using chilled semen produces a higher conception rate than that achieved with frozen semen.

Method: Mares (n = 251) were inseminated with either chilled (n = 112) or frozen (n = 139) semen in the 2006 and 2007 northern hemisphere breeding season. Per rectum ultrasonography of the mare's reproductive tract determined the timing of insemination, and deslorelin acetate was used to induce ovulation. Chilled semen insemination was performed using a single preovulatory dose delivered into the uterine body. Frozen semen was administered as 2 doses (pre‐ and post ovulation) using a deep uterine insemination technique. Pregnancy was detected ultrasonographically at 15 days post insemination. Conception rates were compared using a Chi‐squared test.

Results: Insemination with frozen semen produced a significantly (P = 0.022) higher seasonal conception rate (82.0%) than that achieved with chilled semen (69.6%).

Conclusions and potential relevance: Insemination with frozen semen can achieve conception rates equal to those with chilled semen, enabling the mare owner a greater selection of stallions.
Development of equine upper airway fluid mechanics model for Thoroughbred racehorses
Authors: RAKESH V. , DUCHARME N. G. , DATTA A. K. , CHEETHAM J. , PEASE A. P.
Published: September 2008

Reason for performing study: Computational fluid dynamics (CFD) models provide the means to evaluate airflow in the upper airways without requiringin vivoexperiments.

Hypothesis: The physiological conditions of a Thoroughbred racehorse's upper airway during exercise could be simulated.

Methods: Computed tomography scanned images of a 3‐year‐old intact male Thoroughbred racehorse cadaver were used to simulatein vivogeometry. Airway pressure traces from a live Thoroughbred horse, during exercise was used to set the boundary condition. Fluid‐flow equations were solved for turbulent flow in the airway during inspiratory and expiratory phases. The wall pressure turbulent kinetic energy and velocity distributions were studied at different cross‐sections along the airway. This provided insight into the general flow pattern and helped identify regions susceptible to dynamic collapse.

Results: The airflow velocity and static tracheal pressure were comparable to data of horses exercising on a high‐speed treadmill reported in recent literature. The cross‐sectional area of the fully dilatedrima glottidiswas 7% greater than the trachea. During inspiration, the area of highest turbulence (i.e. kinetic energy) was in the larynx, the rostral aspect of the nasopharynx was subjected to the most negative wall pressure and the highest airflow velocity is more caudal on the ventral aspect of the nasopharynx (i.e. the soft palate). During exhalation, the area of highest turbulence was in the rostral and mid‐nasopharynx, the maximum positive pressure was observed at the caudal aspect of the soft palate and the highest airflow velocity at the front of the nasopharynx.

Conclusions and clinical relevance: In the equine upper airway collapsible area, the floor of the rostral aspect of the nasopharynx is subjected to the most significant collapsing pressure with high average turbulent kinetic during inhalation, which may lead to palatal instability and explain the high prevalence of dorsal displacement of the soft palate (DDSP) in racehorses. Maximal abduction of the arytenoid cartilage may not be needed for optimal performance, since the trachea cross‐sectional area is 7% smaller than therima glottidis.
Effects of a MAPK p38 inhibitor on lung function and airway inflammation in equine recurrent airway obstruction
Authors: LAVOIE J.‐P. , THOMPSON D. , HAMILTON E. , DEBRUE M. , DAVID F. , HICKEY G.
Published: September 2008

Reasons for performing study: It has been suggested that many of the beneficial effects of corticosteroids are mediated through mitogen‐activated protein kinase (MAPK) p38 inhibition.

Objective: To investigate the efficacy of the MAPK p38 inhibitor compound MRL‐EQ1 to either prevent(Phase 1)or treat(Phase 2)recurrent airway obstruction (RAO) in horses.

Methods: MRL‐EQ1 was administered i.v. at a dosage of 0.75‐1.5 mg/kg bwt q. 12 h. InPhase 1, susceptible horses in clinical remission were divided into 2 groups (n = 5/group), based on historical values of respiratory mechanics. All horses were entered in the study in pairs (one control, one treated horse) and exposed to the same environmental challenge (stabling, mouldy hay and dusty conditions). The treatment group received MRL‐EQ1 for 14 days while the control horses were untreated during the same period. InPhase 2, affected horses were ranked by severity of respiratory dysfunction and split randomly into either dexamethasone or MRL‐EQ1 treatment groups (n = 5/group). Bronchoalveolar lavage fluid, respiratory mechanic measurements, MRL‐EQ1 plasma concentration and tumour necrosis factor (TNF) whole blood activity were evaluated sequentially.

Results: InPhase 1, MRL‐EQ1 did not prevent the occurrence of clinical signs and pulmonary inflammation. However, treatment was associated with a reduction in severity and a delay in the onset of signs and a reduction in pulmonary neutrophilia. InPhase 2, plasma concentrations achieved resulted inex vivosuppression of lipopolysaccharide‐induced TNF production in equine blood. MRL‐EQ1 did not improve airway inflammation or lung function and was associated in a dose dependent manner with behavioural (depression, excitability) and blood changes (neutrophilia, increased serum muscle enzyme concentrations).

Conclusions: Inhibition of p38 in the horse was partially effective in reducing clinical signs and airway inflammation when administered prior to, but not during clinical exacerbation in RAO.

Potential relevance: Inhibitors of p38 MAPK with a better toxicity profile may be effective in the prevention or treatment of RAO.
The creation of an international audit and database of equine colic surgery: Survey of attitudes of surgeons
Authors: MAIR T. S. , WHITE N. A.
Published: September 2008

Reasons for performing study: Currently, there is a lack of available evidence‐based data concerning the optimum treatments for horses affected by different types of colic and this precludes the application of clinical audit in this area. In order to accumulate such data, a large‐scale, multicentre database of the outcomes of colic surgery is proposed. The attitudes of surgeons is an important consideration in determining the feasibility of developing this database.

Objectives: To assess attitudes and opinions of equine surgeons concerning clinical audit and to assess the perceived advantages and problems of setting up a large‐scale international audit/database of colic surgery.

Methods: Interviews were conducted with 30 equine surgeons (large animal/equine surgeons who are diplomates of either the American College of Veterinary Surgeons or the European College of Veterinary Surgeons). Questionnaires were sent by e‐mail to 98 equine surgeons.

Results: Face to face interviews were conducted (n = 30) and 43/98 completed questionnaires received (44%). The results of the 2 techniques were very similar. There was generally a high level of interest in the development of a large scale database of colic surgery, but perceived problems included time to collect and submit data, and confidentiality issues. A minority of surgeons reported that they were undertaking any form of specific monitoring of the results of colic surgery within their hospitals.

Conclusions: There is a good level of interest among equine surgeons to develop a large scale database of colic surgery and most would be willing to contribute data from their own hospitals provided that data collection is quick and easy, and that confidentiality is maintained.

Potential relevance: A large scale audit and database would provide relevant information to equine surgeons concerning the current success and complication rates of colic surgery. Such evidence‐based data could be used in clinical audits within individual equine hospitals. The data would also be useful to identify trends within the discipline and could highlight areas that would benefit from active research.
Serum concentrations of lidocaine and its metabolites after prolonged infusion in healthy horses
Authors: DICKEY E. J. , McKENZIE H. C. , BROWN J. A. , DE SOLIS C. N.
Published: September 2008

Reasons for performing study: Continuous‐rate infusions (CRI) of lidocaine are often used for prolonged duration but, to date, only limited time/concentration relationships administered as a short term (24 h) CRI have been reported.

Objective: To determine the time/concentration profile of lidocaine and its active metabolites glycinexylidide (GX) and monoethylglycinexylidide (MEGX) during a 96 h lidocaine infusion.

Methods: Lidocaine was administered to 8 mature healthy horses as a continuous rate infusion (0.05 mg/kg bwt/min) for 96 h. Blood concentrations of lidocaine, GX and MEGX were determined using high performance liquid chromatography during and after discontinuation of the infusion.

Results: Serum lidocaine concentrations reached steady state by 3 h and did not accumulate thereafter. Concentrations were above the target therapeutic concentration (980 ng/ml) only at 6 and 48 h, and did not reach the range described as potentially causing toxicity (>1850 ng/ml) at any time. MEGX did not accumulate over time, while the GX accumulated significantly up to 48 h and then remained constant. The serum concentrations of lidocaine, MEGX and GX were below the limit of detection within 24 h of discontinuation of the infusion. None of the horses developed any signs of lidocaine toxicity during the study.

Conclusions: The metabolism of lidocaine was not significantly impaired by prolonged infusion and no adverse effects were observed. Prolonged infusions appear to be safe in normal horses but the accumulation of GX, a potentially toxic active metabolite, is cause for concern.

Clinical relevance: Although the toxic level of GX has not yet been determined, such accumulation could lead potentially to adverse side effects and it is important to consider this potential for accumulation when utilising prolonged lidocaine infusions.
Large colon resection and anastomosis in horses: 52 cases (1996–2006)
Authors: DRISCOLL N. , BAIA P. , FISCHER A. T. , BRAUER T. , KLOHNEN A.
Published: September 2008

Reasons for performing study: Large colon resection and anastomosis (LCRA) is the most aggressive method of surgical management of a colon with questionable viability. Currently, published studies are comprised mostly of broodmares and discuss short‐term survival.

Objectives: To determine the prognosis for survival after LCRA in a diverse population of horses, report the incidence of post operative complications, and determine if associations between analysed variables and survival rate exist.

Methods: The medical records of 52 horses that underwent LCRA were evaluated. Data were used to identify univariable associations with survival as well as complications related to LCRA. Chi‐square, odds ratio with 95% confidence interval, Mann‐Whitney or Kruskal‐Wallis tests were used, with significance set at P<0.05.

Results: Forty‐four horses (84.6%) survived anaesthesia and recovery, 30 (57.7%) survived to be discharged from the hospital. Of the variables analysed, heart rate 24 h after recovery was significantly associated with mortality, as were endotoxaemia, ileus and peritonitis experienced post operatively.

Conclusions: Heart rate 24 h after recovery may be a more reliable prognostic indicator than other analysed variables. Survival rate and complications after LCRA were similar to those previously reported.

Potential relevance: By reporting on LCRA in a diverse group of horses, referral clinics with similar populations may have a better understanding of prognosis and complications associated with the procedure. When a colon with questionable viability is removed, waiting until 24 h after recovery may be advised to allow for a more informed decision regarding prognosis.
Determination of the source of increased serotonin (5‐HT) concentrations in blood and peritoneal fluid of colic horses with compromised bowel
Authors: DELESALLE C. , van de WALLE G. R. , NOLTEN C. , ver DONCK L. , van HEMELRIJCK A. , DRINKENBURG W. , DE BOSSCHERE H. , CLAES P. , DEPREZ P. , LEFERE L. , TORFS S. , LEFEBVRE R. A.
Published: September 2008

Reasons for performing study: Increased plasma (5‐HT) concentrations are reported in horses predisposed to develop laminitis and after i.v. infusion of endotoxins. In the equine jejunum contractile 5‐HT1A‐like receptors show tachyphylaxia upon prolonged activation with 5‐HT. Therefore, increased systemic 5‐HT release in colic horses could play a possible role in the pathophysiology of ileus.

Objective: To investigate possible increased systemic release of 5‐HT in colic horses with compromised bowel and to identify the source of 5‐HT overload.

Methods: Concentrations of 5‐HT were determined in plasma and peritoneal fluid (PF) of healthy horses (n = 10), strangulating small intestinal colic horses (n = 18), nonsurgical colic horses (n = 10) and cryptorchid stallions (n = 6). It was attempted to identify the source of 5‐HT overload by comparing the blood and PF 5‐HT concentrations within horses and by assessing thein vivoplatelet activation through determination of the β‐thromboglobulin (β‐TG)/platelet factor 4 (PF4) ratio.

Results: All horses in the strangulating small intestinal colic group had plasma (P = 0.006) and PF (P = 0.01) 5‐HT concentrations above those found in the control group. Plasma β‐TG/PF4 ratio in these horses exceeded 2 in all cases, indicatingin vivoplatelet activation. Concentrations of 5‐HT in PF of colic horses with compromised bowel were significantly lower than the corresponding plasma concentrations (P = 0.005).

Potential relevance: In horses with compromised bowel, significant amounts of 5‐HT can be released into the systemic circulation, through massive release of platelet‐stored 5‐HT. 5‐HT is a very potent proinflammatory, vasoconstrictive and immunomodulatory agent. In view of the rapid and prolonged tachyphylaxia, shown for the jejunal 5‐HT1A‐like receptors, this increased systemic 5‐HT release could play a role in the pathophysiology of ileus in horses.
Effect of a novel solution for organ preservation on equine large colon in an isolated pulsatile perfusion system
Authors: POLYAK M. M. R. , MORTON A. J. , GROSCHE A. , MATYJASZEK S. , FREEMAN D. E.
Published: September 2008

Reasons for performing study: Several therapeutic agents have been tested in models of ischaemia and reperfusion injury (IRI) in equine jejunum, with mixed results. This study was based on the use of an organ perfusion solution (OPS) designed to protect human allografts from IRI.

Hypothesis: A modified OPS can preserve the integrity of equine large colon during 12 h of isolated pulsatile perfusion, in the absence of oxygen and blood.

Methods: Segments of large colon were removed from anaesthetised horses, the contents removed and the mucosa rinsed with 0.9% saline. Experimental segments were perfused for 12 h with one litre modified OPS (n = 7) delivered by pulsatile flow through an extracorporeal circuit. Control segments (n = 4) were perfused on the same circuit with one litre of autologous blood. Vascular resistance, flow and pressure were measured serially, and aliquots of OPS and blood drawn hourly for routine biochemical analyses. Mucosal biopsies of the experimental and control segments were taken at 0, 6 and 12 h andin vivomucosal tissue at 0 h for baseline comparison. All biopsies underwent histomorphometric analysis and immunohistochemical assessment of calprotectin activity.

Results: All colon segments were machine perfused without technical complications. Vascular and biochemical indices remained constant over 12 h in the OPS group, and were constant over 6 h in the control group, but deteriorated later. Mucosal integrity, expression of cyclooxygenases‐1 and ‐2, and expression of mucosal calprotectin were unchanged in the OPS group compared with the baseline tissues, and mucosal integrity was superior to the control tissues.

Conclusions: A modified OPS designed to target specific pathways of damage from IRI can preserve colonic mucosal integrity for 12 h in the absence of blood and oxygen.

Potential relevance: This extracorporeal system has the potential to preserve equine colon for humane investigation into colonic function and repair over longer periods than previously described for otherin vitroandex vivosystems. Future investigations into use of the modified OPS on injury to equine colon from ischaemia and reperfusion are recommended.
The effects ofStrongylus vulgarisparasitism on eosinophil distribution and accumulation in equine large intestinal mucosa
Authors: ROTTING A. K. , FREEMAN D. E. , CONSTABLE P. D. , MOORE R. M. , EURELL J. C. , WALLIG M. A. , HUBERT J. D.
Published: September 2008

Reasons for performing study: Eosinophilic granulocytes have been associated with parasite or immune‐mediated diseases, but their functions in other disease processes remain unclear. Cause and timing of eosinophil migration into the equine gastrointestinal mucosa are also unknown.

Objective: To determine the effects of intestinal parasitism on eosinophils in equine large intestinal mucosa.

Methods: Large intestinal mucosal samples were collected from horses and ponies (n = 16) from the general veterinary hospital population, ponies (n = 3) raised in a parasite‐free environment, ponies experimentally infected with 500 infectiveStrongylus vulgarislarvae and treated with a proprietary anthelmintic drug (n = 14), and a similar group of ponies (n = 7) that received no anthelmintic treatment. Total eosinophil counts and eosinophil distribution in the mucosa were determined by histological examination. A mixed model analysis was performed and appropriate Bonferroni adjusted P values used for each family of comparisons. P<0.05 was considered significant.

Results: There was no difference in large intestinal mucosal eosinophil counts and eosinophil distribution between ponies infected withS. vulgarisand those raised in a parasite‐free environment. Experimental infection withS. vulgaris, with or without subsequent anthelmintic treatment, did not change eosinophil counts, and counts were similar to those for horses from the general population.

Conclusions: Migration of eosinophils to the equine large intestinal mucosa appears to be independent of exposure to parasites. Large intestinal mucosal eosinophils may have more functions in addition to their role in defence against parasites.

Potential relevance: Exposure to intestinal parasites is not a prerequisite for the presence of mucosal eosinophils in equine large intestine.
Surgical treatment of colic in the miniature horse: A retrospective study of 57 cases (1993–2006)
Authors: HAUPT J. L. , McANDREWS A. G. , CHANEY K. P. , LABBE K. A. , HOLCOMBE S. J.
Published: September 2008

Reasons for performing study: It has been suggested that the rate of post operative abdominal adhesions in miniature horses is higher than that for other breeds. However, few reports exist in the veterinary literature describing complications and long‐term survival following surgical treatment of colic in these horses.

Objectives: To determine the prevalence of surgical lesions in miniature horses with acute abdominal disease in terms of clinical signs, surgical management, post operative treatment and complications, as well as short‐ and long‐term survival.

Methods: Medical records of 57 American Miniature Horses undergoing surgical treatment for acute abdominal pain at the Michigan State University Large Animal Veterinary Teaching Hospital 1993–2006 were evaluated for clinical information. Owners and trainers were contacted to gain information regarding long‐term survival.

Results: The most common surgical lesion was a faecalith (38/57 cases) located primarily within the descending colon and most frequently diagnosed in horses age <6 months (19/38 cases). Short‐term survival to hospital discharge for horses recovered from anaesthesia was 98% (55/56) with the most common post operative complications being diarrhoea and inappetance. Intra‐abdominal adhesions were identified in 2/8 horses requiring a second celiotomy. Long‐term follow‐up was available for 45 horses and 87% (39/45) were alive at least 12 months after surgery.

Conclusions: As previously reported, faecalith obstruction is a frequent surgical lesion in the miniature horse and is most common in miniature horses age <6 months. The incidence of adhesion formation may be lower than previously reported.

Clinical relevance: Ischaemic intestinal lesions are uncommon in miniature horses, as is laminitis, which may be why short‐and long‐term survival is better in this breed compared to others following colic surgery.
Massive pulmonary thromboembolism in six horses
Authors: Norman T. E. , Chaffin M. K. , Perris E. E. , Edwards J. F. , David J. B. , Cohen N. D. , Reuss S.
Published: September 2008

This report involves 6 cases in which medical records andpost mortemfindings were reviewed leading to the diagnosis of massive pulmonary thromboembolism (MPTE). All horses were mature and MPTE has not been recognised previously as a sequel to generalised systemic illness in mature horses.

The clinical data and pathological findings of the cases are reported and the authors conclude that MPTE is an uncommon but important complication of medical and surgical disorders in mature horses. In 3 of the cases, the condition was nonfatal suggesting that some horses having developed PTE survive and the condition may not be recognised in such cases. The incidence of the condition might be higher than supposed.
Cartilage matrix changes in the developing epiphysis: Early events on the pathway to equine osteochondrosis?
Authors: Lecocq M. , Girard C. A. , Fogarty U. , Beauchamp G. , Richard H. , Laverty S.
Published: September 2008

Reasons for performing study: The earliest osteochondrosis (OC) microscopic lesion reported in the literature was present in the femorotibial joint of a 2‐day‐old foal suggesting that OC lesions and factors initiating them may arise prior to birth.

Objective: To examine the developing equine epiphysis to detect histological changes that could be precursors to OC lesions.

Methods: Osteochondral samples from 21 equine fetuses and 13 foals were harvested from selected sites in the scapulohumeral, humeroradial, metacarpophalangeal, femoropatellar, femorotibial, tarsocrural and metatarsophalangeal joints. Sections were stained with safranin O and picrosiruis red to assess cartilage changes and structural arrangement of the collagen matrix.

Results: Extracellular matrix changes observed included perivascular areas of paleness of the proteoglycan matrix associated with hypocellularity and, sometimes, necrotic chondrocytes. These changes were most abundant in the youngest fetuses and in the femoropatellar/femorotibial (FP/FT) joints. Indentations of the ossification front were also observed in most specimens, but, most frequently, in scapulohumeral and FP/FT joints. A cartilage canal was almost always present in these indentations. The vascular density of the cartilage was higher in the youngest fetuses. In these fetuses, the most vascularised joints were the metacarpo‐ and metatarsophalangeal joints but their cartilage canals regressed quickly. After birth, the most vascularised cartilage was present in the FP/FT joint. Articular cartilage differentiated into 4 zones early in fetal life and the epiphyseal cartilage also had a distinct zonal cartilage structure. A striking difference was observed in the collagen structure at the junction of the proliferative and hypertrophic zones where OCD lesions occur.

Conclusion: Matrix and ossification front changes were frequently observed and significantly associated with cartilage canals suggesting that they may be physiological changes associated with matrix remodelling and development. The collagen structure was variable through the growing epiphysis and a differential in biomechanical properties at focal sites may predispose them to injury.
Unexplained underperformance syndrome in sport horses: Classification, potential causes and recognition
Authors: RIVERO J. L. L. , VAN BREDA E. , ROGERS C. W. , LINDNER A. , van OLDRUITENBORGH‐OOSTERBAAN M. M. SLOET
Published: September 2008

When inadequate training stress is applied and recovery time is insufficient, performance reduction and chronic maladaptation occurs. Known as overtraining syndrome (OTS), this complex condition afflicts horses in top training. The name of the syndrome implies causation and it is necessary to differentiate it from over‐reaching, a term used in horses that, after suffering a loss of performance without an obvious clinical reason, recover their performance within 1 or 2 weeks. The term OTS should be used for horses in heavy training losing performance without an obvious clinical reason and which is sustained for >2 weeks. Despite considerable scientific investigations, the underlying mechanisms are still poorly understood and there are no objective biomarkers for OTS. An imbalance between training and recovery seems to be the primary cause of this dysfunction. However, other factors such as transport, feeding, subclinical disease and general management may play a role. There is now sufficient evidence that red cell hypervolaemia is not a mechanism for the OTS in horses. A dysfunction of the hypothalamo‐pituitary‐adrenocortical axis is momentarily the only mechanism that may be related to the development of this syndrome.

In the absence of a scoring system to assess the psychological status of horses, the most effective method for diagnosis is the thorough assessment of the history and presenting complaint (length of unexplained performance deficit, weight loss despite adequate feed intake, concurrence of unspecific subclinical problems, unsuccessful treatments and changes of behaviour). Standardised exercise tests are suggested to provide a way to detect subtle changes in hormonal responses in the individual, which may make an important contribution to the detection of early overtraining. But further longitudinal studies are needed to clarify mechanism(s) underlying OTS and to establish the potential for the use of a physiological test as a predictive tool of this disorder.
Epiphyseal cartilage canal blood supply to the distal femur of foals
Authors: Olstad K. , Ytrehus B. , Ekman S. , Carlson C. S. , Dolvik N. I.
Published: September 2008

Reasons for performing study: The developmental pattern of the cartilage canal blood supply to epiphyseal growth cartilage has been linked to osteochondrosis (OC) in the tarsus of foals. This pattern has not yet been described in the distal femur, another site frequently affected by OC.

Objective: To describe the developmental pattern of the blood supply to the distal femoral epiphyseal growth cartilage in 8 Standardbred foals age 0–7 weeks.

Methods: One foal was sacrificed weekly from birth to age 7 weeks (n = 8) to undergo a barium perfusion procedure to demonstrate vessels within cartilage canals of one hindlimb. The distal end of the femur was cleared in methyl salicylate and perfused vessels were studied in the intact bones. Each distal femur was then sawed into 5 mm thick slabs in the transverse plane, and the slabs decalcified and radiographed. Finally, the lateral trochlear ridge was separated from each slab and examined histologically.

Results: The cartilage canal blood supply regressed with increasing age, but several regions remained vascularised in the oldest foal at age 7 weeks. Vessels arose from perichondrial and subchondral arterial sources, and coursed perpendicular or parallel to the ossification front. The midsection of parallel vessels became incorporated into the ossification front during growth. Anastomoses formed and vessels within the distal portion of canals with an original perichondrial source shifted to use subchondral vessels as their arterial source. Both parallel and perpendicular vessels therefore traversed the ossification front to enter cartilage canals. No histological lesions were observed in sections from any of the foals.

Conclusion: The same anatomical feature (traversing the ossification front to enter cartilage canals) reported to render vessels vulnerable to failure in the tarsus was also present in the distal femur of foals.

Potential relevance: OC may occur by the same pathogenetic mechanism in the distal femur as in the tarsus of foals.
Gastric and small intestinal ileus as a cause of acute colic in the post parturient mare
Authors: HILLYER M. H. , SMITH M. R. W. , MILLIGAN P. J. P.
Published: September 2008

Reasons for performing study: Ileus (functional obstruction of aboral gastrointestinal transit) is an uncommon cause of gastrointestinal dysfunction and colic in the horse. A number of specific conditions have been previously reported in association with ileus. This report describes the recognition of primary gastric and small intestinal ileus of undetermined cause in a series of post parturient mares.

Objectives: To describe the clinical features, treatment and outcome of a series of episodes of primary gastric and small intestinal ileus.

Methods: A retrospective study was performed of colic episodes seen in an equine practice in Newmarket, UK over a 6 year period (2002–2007).

Results: Seventeen episodes of gastric and small intestinal ileus were identified, which occurred in 15 horses. All episodes occurred in post parturient mares. No previously reported cause of ileus was identified in any of the episodes. Fifteen of the 17 episodes received medical treatment (medical support and nasogastric decompression) and, in addition, surgical decompression was performed in 9 episodes. Two mares were subjected to euthanasia before treatment due to the presence of gastric rupture and the remaining 13 mares survived with a follow‐up period of at least 10 months. Two mares suffered a further episode of gastric and small intestinal ileus, one 4 days and the other 2 years after the initial episode.

Conclusions: Gastric and small intestinal ileus of, as yet, unknown aetiology appears to be a potential cause of acute colic in the post parturient mare. The outcome following treatment by decompression is good.

Potential relevance: Knowledge of this condition should allow early recognition and successful treatment of future episodes. Further epidemiological studies are needed to allow the aetiology of the condition to be determined.
Characterisation of the inflammatory reaction in equine idiopathic focal eosinophilic enteritis and diffuse eosinophilic enteritis
Authors: MAKINEN P. E. , ARCHER D. C. , BAPTISTE K. E. , MALBON A. , PROUDMAN C. J. , KIPAR A.
Published: September 2008

Reasons for performing study: Idiopathic focal eosinophilic enteritis (IFEE) and diffuse eosinophilic enteritis (DEE) are primary eosinophilic intestinal conditions without a known cause that are associated with an increasing number of surgical colic cases. Histology may be helpful in defining disease aetiology and pathogenesis.

Objectives: To characterise further the inflammatory infiltrate in equine IFEE and to compare the condition with DEE.

Methods: Twenty‐three IFEE cases and 5 DEE cases were examined by light microscopy including immunohistology to identify infiltrating leucocytes. Inflammatory infiltrates in mucosa and submucosa were characterised in IFEE lesions (Group 1), the intestine distant from the lesions in IFEE (Group 2) and DEE (Group 3).

Results and conclusions: IFEE lesions represented an accumulation of leucocytes in submucosa andmuscularis, with dominance of eosinophils and macrophages and smaller numbers of lymphocytes, plasma cells and neutrophils. T cells represented the dominant lymphocytes. The mucosa overlying the lesion and both mucosa and submucosa in IFEE nonlesion sites and in DEE exhibited a similar composition, with different prevalence of various cell types. Macrophages were significantly more prevalent in the mucosal and submucosal infiltrates in IFEE nonlesion sites than in DEE, and lymphocytes significantly more prevalent in the mucosa in DEE than in IFEE nonlesion sites. The findings confirm IFEE as a primary eosinophilic intestinal disorder and indicate that IFEE represents a focally exacerbated inflammatory reaction in horses with DEE, possibly due to functional changes in the macrophage and T cell components, with subsequent excessive recruitment of both eosinophils and macrophages.

Potential relevance: This characterisation of the inflammatory reaction in IFEE and DEE represents the first comparative report on primary eosinophilic intestinal disorders in horses. It provides a starting point for more detailed investigations into the factors promoting these conditions.
Equine gastrointestinal motility research: Where we are and where we need to go
Authors: HUDSON N. P. H. , MERRITT A. M.
Published: September 2008

Equine gastrointestinal motility is a central issue in cases of equine colic, post operative convalescence and alimentary conditions encountered in practice. There are significant syndromes of intestinal dysmotility in the horse such as obstructive disorders and post operative ileus that are still poorly understood. This review describes the various areas of research that aim to elucidate the pathogenesis of intestinal hypo‐ or hypermotility by research methods, which include studies at the cellular level, and those that employin vitroorin vivotechniques of evaluating the physiology and mechanical means of ingesta transit through the alimentary tract. The review discusses future directions for studies which will hopefully lead to better understanding and appropriate measures for diagnosis, therapy and prevention of ileus and other motility disorders.