bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

SummaryReasons 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

SummaryReasons 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

SummaryReasons 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

SummaryReasons 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

SummaryThis 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

Summary 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

SummaryWhen 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

SummaryReasons 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

SummaryReasons 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

SummaryReasons 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

SummaryEquine 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.
Endothelin mediated contraction of equine laminar veins
Authors: Keen J. A. , Hillier C. , Mcgorum B. C. , Nally J. E. 
Published: September 2008

SummaryReasons for performing study: Endothelin‐1 (ET‐1) may be a key mediator in the pathogenesis of laminitis, but endothelin‐mediated responses in the venous microcirculation of the equine foot have yet to be fully characterised.Objectives: To characterise the response of equine laminar veins to ET‐1 and evaluate the ET‐1 receptor subtypes that mediate this response.Methods: Small veins (150–500 μm) draining the equine digital laminae from healthy horses and ponies subjected to euthanasia at an abattoir were investigated using wire myography. Concentration response curves were constructed for ET‐1 in the presence of ETA(BQ123) and ETB(BQ788) receptor antagonists, and L‐NAME, a nitric oxide synthase blocker. The selective ETBreceptor agonist BQ3020 was investigated alone and following incubation with L‐NAME, with or without BQ788.Results: Endothelin‐1 contraction of laminar veins was significantly inhibited by BQ123 but not by BQ788. In the presence of L‐NAME, sensitivity of laminar veins to ET‐1 was enhanced 4‐fold, and further addition of BQ788 did not alter this increased sensitivity. BQ3020 induced no venoconstriction; however, in the presence of L‐NAME, it caused contraction of veins with approximately 30% of the efficacy of ET‐1. The action of BQ3020 in the presence of L‐NAME was abolished by BQ788.Conclusions: Both ETAand ETBreceptors are involved in the net tonic response to ET‐1 in normal laminar veins. A population of ETBreceptors may be present on the vascular endothelium and on smooth muscle of laminar veins, and the action of ET‐1 at these 2 sites is likely to be approximately equal and opposite.Potential relevance: Our results clarify the function of the ET‐1 receptor subtypes in laminar veins from healthy horses. Further study of ET‐1 receptors in laminitic horses is therefore warranted.