Neil Hudson

Interstitial cells of Cajal (ICC) in equine colic: an immunohistochemical study of horses with obstructive disorders of the small and large intestines

REASONS FOR PERFORMING STUDY The gastrointestinal pacemaker cells, the interstitial cells of Cajal (ICC), have been implicated in several human gastrointestinal dysmotility syndromes. Recently, the involvement of these cells in equine gastrointestinal diseases has been investigated in cases of equine grass sickness where a significant reduction in ICC density was observed. OBJECTIVE To investigate ICC density in equine obstructive gastrointestinal disorders using immunohistochemical labelling methods. METHODS Intestinal samples were analysed from 44 horses undergoing exploratory surgery for colic and from 11 control animals subjected to euthanasia for conditions not related to the gastrointestinal tract. Immunohistochemical labelling of ICC was carried out using an anti-c-Kit antibody. Two independent observers assessed ICC density using a semiquantitative grading system. RESULTS There was a significant reduction in ICC density in horses with large colon disorders compared to the controls (P<0.01). Horses with strangulating lesions of the small intestine showed no difference when compared to the controls. CONCLUSIONS There was a reduction in ICC density in horses with large intestinal disorders. POTENTIAL RELEVANCE The reduction in ICC density may be associated with the clinical findings as well as recurrent colic episodes observed in a number of these cases. This immunohistochemical study provides a basis for future functional electrophysiological investigations to determine the precise effect of ICC reduction on equine intestinal motility.

A reduction in interstitial cells of Cajal in horses with equine dysautonomia (grass sickness).

Equine dysautonomia (grass sickness) is a common, frequently fatal disease of horses characterised by dysfunction of the gastrointestinal tract. Interstitial cells of Cajal are the c-Kit-immunoreactive cells responsible for the generation of pacemaker activity in gastrointestinal smooth muscle. Impairment of this pacemaker action has been implicated in several motility disorders in humans and laboratory mammals. The aim of this study was to test the hypothesis that changes in interstitial cells of Cajal may be involved in the pathophysiology of the intestinal dysfunction observed in equine grass sickness. Interstitial cells of Cajal were identified using immunohistochemical labelling with an anti-c-Kit antibody and their density was assessed using a semi-quantitative grading system. Segments of ileum were examined from 24 horses free from gastrointestinal disease and compared to tissues from 28 horses with grass sickness. Segments of the pelvic flexure region of the large colon were examined from 13 horses free from gastrointestinal disease and compared to tissues from 10 horses with grass sickness. In horses with grass sickness, interstitial cells of Cajal were significantly decreased in both the myenteric plexus and circular muscle regions of both ileum and pelvic flexure compared to normal animals. Therefore, it is possible that the decline in interstitial cells of Cajal may be an important factor in the development of intestinal dysmotility observed in grass sickness.

The transition into veterinary practice: Opinions of recent graduates and final year students

BackgroundThe transition from veterinary student to member of the veterinary profession is known to be challenging. This study aimed to determine and compare the opinions of final year veterinary students and recent graduates on graduate attributes that ease this transition.MethodsThe study was carried out across 3 veterinary schools in the United Kingdom. Paper based or electronic surveys were used. Final year students in the 3 schools were surveyed either electronically (school A) or on paper (schools B and C). Student cohort sizes were 112, 227 and 102 respectively. Recent graduates were contacted either at a reunion event (school A) or electronically from database records (school B and school C). Cohort sizes of contacted graduates were 80, 175 and 91 respectively. Respondents were asked to rate 42 individual attributes on a 5 point Likert scale. Focus groups with final year students and recent graduates and telephone interviews with recent graduates were carried out. Data were analysed by two researchers through a combination of manual coding and thematic analysis. Data were grouped into broad themes then sorted into narrower themes. Data were then searched for counter examples.ResultsResponse rates for final year students were 34% (school A), 36% (school B) and 40% (school C). Response rates for recent graduates were 56% (school A), 20% (school B) and 11% (school C). There was a high level of agreement between the cohorts with respect to communication skills, problem solving and decision making skills, recognition of own limitations and the ability to cope with pressure all rated unanimously important or very important. Business acumen, knowledge of veterinary practice management and research skills were the 3 attributes ranked at the bottom of the list. Nine attributes were identified with a significantly different (p < 0.05) ranking between the cohorts. Final year students ranked veterinary clinical knowledge, knowledge of veterinary public health and zoonotic issues, veterinary legislation and veterinary practice management, commitment to continuing professional development and ability to evaluate information higher than recent graduates. Recent graduates ranked the attributes of integrity, friendliness and compassion higher than final year students.ConclusionsRecent graduates and final year students rate highly the attributes which help foster the client/veterinarian relationship. Recent graduates reflect that a focus on knowledge based attributes is less important once in practice when compared to final year. The study confirms the importance to recent graduates and final year students of attributes considered as non-technical in the transition to working in the veterinary profession.

Equine grass sickness

Equine grass sickness (EGS; equine dysautonomia) is a polyneuronopathy affecting both the central and the peripheral nervous systems of horses. As the name implies, EGS almost exclusively affects grazing horses, resulting in the development of a characteristic array of clinical signs, most of which can be attributed to neuronal degeneration in the autonomic and enteric nervous systems. Varying disease severities occur, largely determined by the extent of neuronal degeneration in the myenteric and submucous plexuses of the enteric nervous system. Extensive neuronal degeneration, as seen in acute and subacute forms of EGS, results in intestinal dysmotility, the severity of which is incompatible with survival. In comparison, a proportion of chronic forms of EGS, characterised by less severe neuronal degeneration, will survive. Despite extensive research efforts since EGS was first reported over 100 years ago, the precise aetiology remains elusive. This article reviews much of the scientific literature on EGS, covering epidemiology, pathology, diagnosis, treatment and aetiological hypotheses.

Perceptions of clients and veterinarians on what attributes constitute ‘a good vet’

The perceptions of veterinarians and small animal (SA) clients on what attributes constitute ‘a good veterinarian’ were examined by a questionnaire survey. The respondents were asked to record how important they considered 20 attributes for a veterinary surgeon to have on a five-point scale from ‘not at all important’ to ‘very important’. In addition, they were asked to list which attributes they considered to be the three most important attributes in a veterinary surgeon; finally, they were asked whether there were any additional attributes that they considered to be highly desirable in a veterinary surgeon. In total, 407 SA clients, 243 SA veterinarians and 61 non-SA veterinarians completed the questionnaire. There were significant differences in the proportion of clients who considered an attribute to be ‘very important’ compared with SA veterinarians for 12 of the 20 attributes (P<0.005). A larger proportion of clients considered ‘confidence’, ‘knowledge about veterinary medicine and surgery’, ‘cleanliness’, ‘good at explaining technical terms’, ‘patience’, ‘clear about cost of treatment’, ‘ability to work in a team’, ‘honesty’, ‘politeness’, ‘decisiveness’, ‘good with animals’ and ‘good practical skills’ to be ‘very important’ attributes than the SA veterinarians; a larger proportion of SA veterinarians considered ‘good communication skills’ to be a ‘very important’ attribute than the clients.

Presence of in vitro electrical activity in the ileum of horses with enteric nervous system pathology: equine dysautonomia (grass sickness)

Equine dysautonomia (grass sickness) is a frequently fatal disease of horses characterised by intestinal stasis. Interstitial cells of Cajal (ICC) are the pacemakers and mediators of neurotransmission in the gastrointestinal tract. Impaired ICC-mediated control of motility has been implicated in intestinal disorders in laboratory mammals, humans and in equine grass sickness. The aim of this study was to compare the in vitro electrical properties of ileum from grass sickness cases with horses free from gastrointestinal disease. Intracellular microelectrode recordings were made from smooth muscle cells in cross-sectional preparations of equine ileum, superfused in vitro. Samples were taken from six horses with grass sickness and from eight horses free from gastrointestinal disease, all euthanised on humane grounds. Ileal tissues were processed for haematoxylin and eosin histology, and c-Kit immunohistochemistry. Membrane potential oscillations were recorded in the ileal preparations from four of the six horses with grass sickness and from all of the normal horses. A waxing and waning pattern of the membrane potential oscillation activity was noted in some cells. In comparison to the normal horses, the membrane potential oscillations in grass sickness horses had a significantly reduced frequency (P = 0.0001) and increased duration (P = 0.0002). Immunohistochemistry revealed the presence but reduction of ICC in grass sickness. Histological assessment of the same tissues used for analysis of the ICC showed the depletion and pathology of the enteric neurons in grass sickness. Therefore, the majority of ileal preparations from grass sickness-affected horses exhibited prominent membrane potential oscillation activity suggesting that, although the neural elements are damaged severely, the ICC-mediated pacemaker function remains intact.

Clinical features and management of equine post operative ileus: Survey of diplomates of the European Colleges of Equine Internal Medicine (ECEIM) and Veterinary Surgeons (ECVS)

REASONS FOR PERFORMING STUDY There is a need for an improved understanding of equine post operative ileus (POI), in terms of both clinical definition and optimal management. Although the pharmacological strategies that are used to treat POI continue to evolve, little is known about the supplementary strategies used to prevent and manage this condition. OBJECTIVES To report the current strategies used to diagnose, prevent and manage POI following emergency abdominal surgeries. STUDY DESIGN Cross-sectional survey. METHODS An electronic survey invitation was sent by email to 306 European college diplomates (European Colleges of Equine Internal Medicine, ECEIM n = 120, and Veterinary Surgeons, ECVS n = 186). RESULTS The response rate was 33% (100 of 306). The median reported estimated incidence of POI was 10-20%. The presence of reflux on nasogastric intubation was the main criterion used to define POI. Lesions involving the small intestine were thought to be the leading risk factors for developing POI. Anti-inflammatory drugs, antimicrobial drugs and i.v. fluids were the primary preventative strategies when managing cases at high risk for POI. Flunixin meglumine and lidocaine were the drugs most commonly used to treat horses with POI. Supplementary preventative and treatment strategies for POI included control of endotoxaemia, fluid therapy, early ambulation and judicious timing of post operative feeding. CONCLUSIONS Appreciation of the potential risk factors associated with the development of POI appeared to have an impact on the choice of management strategies that are implemented. The majority of ECEIM and ECVS Diplomates in the survey used flunixin meglumine and lidocaine, often in combination, to treat horses with POI, which is likely to reflect the contributory role of inflammation in its pathophysiology. Various supplementary strategies were used to prevent and manage POI risk factors intraoperatively and post operatively.

Equine gastrointestinal motility research : Where we are and where we need to go

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 employ in vitro or in vivo techniques 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.

Multifocal eosinophilic enteritis associated with a small intestinal obstruction in a standardbred horse

A seven-year-old standardbred gelding developed marked signs of colic associated with an acute small intestinal obstruction. Surgical exploration revealed three intramural, circumferential constricting lesions in the small intestine, the two most severe of which were in the jejunum and were resected. The horse was euthanased owing to postoperative complications. Histopathological examination confirmed the diagnosis of idiopathic multifocal eosinophilic enteritis.

Clinical features and management of equine post operative ileus (POI): Survey of Diplomates of the American Colleges of Veterinary Internal Medicine (ACVIM), Veterinary Surgeons (ACVS) and Veterinary Emergency and Critical Care (ACVECC)

REASONS FOR PERFORMING STUDY A recent survey of European Colleges (European College of Equine Internal Medicine [ECEIM] and European College of Veterinary Surgeons [ECVS]) revealed the different strategies implemented by, and some of the challenges facing, European clinicians presented with cases of post operative ileus (POI). It was concluded that further comparative analysis of opinions, canvassed from additional colleges of equine veterinary specialism worldwide, would provide valuable additional insight into current POI knowledge on a more global scale. OBJECTIVES To report and compare the current strategies favoured by American veterinary specialists when managing POI in horses that underwent emergency colic surgery. STUDY DESIGN Cross-sectional survey. METHODS Electronic invitations were sent to 814 Large Animal specialists, including 3 colleges: the American College of Veterinary Internal Medicine (ACVIM), American College of Veterinary Surgeons (ACVS) and the American College of Veterinary Emergency and Critical Care (ACVECC). RESULTS The response rate was 14% (115/814). The majority of respondents (68%) reported an estimated prevalence range of POI of 0-20%. The presence of reflux on nasogastric intubation was the main criterion used to define POI. A lesion involving the small intestine was considered the main risk factor for POI. Anti-inflammatory drugs, intravenous (i.v.) fluids and antimicrobial drugs were the primary strategies used when managing POI. Flunixin meglumine and i.v. lidocaine were the drugs most commonly used in the treatment of horses with POI. Supplementary management strategies targeted mainly the prevention of post operative adhesions, infection and inflammation. CONCLUSIONS There is a lack of consensus on the clinical definition of POI. Prospective and objective clinical assessment of the effectiveness of the different strategies contained within this and the European survey is necessary in order to identify a standardised approach to the management of equine POI.