The ultrasonographic appearance of the ileocecocolic junction (ICCJ), comprising the ileocolic junction (ICJ) and the cecocolic junction (CCJ), has not been established in dogs. The purpose of this prospective study was (1) to evaluate the feasibility and technique of systematic ultrasonographic evaluation of the ICJ and CCJ and (2) to describe its ultrasonographic features. Abdominal ultrasound was performed in 102 fasted dogs, free of digestive signs. The time required to identify the ICJ using a standardized method was recorded for each operator and compared among four experienced ultrasonographers (ECVDI certified and associated member ECVDI) and two previously trained ECVDI residents to evaluate the feasibility of the technique. Measurements were obtained for the ICJ wall thickness. Evaluation of the contents and peristalsis of the ICJ was recorded for descriptive purposes. The easiest way to identify the ICJ was to follow the colon proximally from the urinary bladder to the ICJ. The probe was then rotated anticlockwise and shifted slightly laterally while increasing the pressure to obtain a longitudinal section of the ICJ. The ICJ was identified in less than 2 min in 98% of cases by experienced ultrasonographers and in 86% of cases by ECVDI residents. The canine ICJ appears as a short invagination of the ileum into the colon, whereas the CCJ appears as a small opening of the colon within the cecum. This study suggests that it is possible to nearly systematically identify the ICCJ with ultrasound in dogs using the described method and provides reference values for its ultrasonographic measurements.

Small intestinal bacterial overgrowth (SIBO) is a significant and increasingly recognized syndrome. While the development may be multifactorial, impairment of the ileocecal valve (ICV), small bowel motility, and gastric acid secretion have been hypothesized to be risk factors. ICV dysfunction remains largely unexplored using standard technology. The wireless motility capsule (WMC) that evaluates pressure, pH, and temperature throughout the GI tract provides the ability to assess these parameters.

The primary aims of this study were to assess the relationship of ICV pressures, small bowel transit time (SBTT) and intestinal pH with lactulose hydrogen breath testing (LBT) results in subjects with suspected SIBO.

We retrospectively studied consecutive patients referred to our institution for WMC and LBT from 2010-2012. Ileocecal junction pressures (IJP), as a surrogate for ICV pressures, were defined as the highest pressure over a 4-min window prior to the characteristic ileocecal pH drop. SBTT and pH were calculated and compared with LBT results.

Twenty-three patients underwent both WMC and LBT, with positive results observed in 15 (65.2%). IJP were significantly higher in LBT(-) negative vs. LBT(+) (79.9 vs. 45.1, p < 0.01). SBTT was significantly longer in LBT(+) versus LBT(-) (5.82 vs. 3.81 h, p = 0.05). Among LBT(+) subjects, gastric pH was significantly higher versus LBT(-) subjects (2.76 vs. 1.63, p = 0.01). There was poor correlation between IJP and other parameters (SBTT, small bowel pH, and gastric pH).

Low IJP is significantly associated with SIBO. While this is physiologically plausible, to our knowledge, this is the first study to make this connection. Prolonged SBTT and higher pH are also independently associated with SIBO. Our findings add value of the WMC test as a diagnostic tool in patients with functional gastrointestinal complaints and suggest re-focus of attention on the ileocecal valve as a prominent player in intestinal disorders.

To explore whether patients with a defective ileocecal valve (ICV)/cecal distension reflex have small intestinal bacterial overgrowth.

Using a colonoscope, under conscious sedation, the ICV was intubated and the colonoscope was placed within the terminal ileum (TI). A manometry catheter with 4 pressure channels, spaced 1 cm apart, was passed through the biopsy channel of the colonoscope into the TI. The colonoscope was slowly withdrawn from the TI while the manometry catheter was advanced. The catheter was placed across the ICV so that at least one pressure port was within the TI, ICV and the cecum respectively. Pressures were continuously measured during air insufflation into the cecum, under direct endoscopic visualization, in 19 volunteers. Air was insufflated to a maximum of 40 mmHg to prevent barotrauma. All subjects underwent lactulose breath testing one month after the colonoscopy. The results of the breath tests were compared with the results of the pressures within the ICV during air insufflation.

Nineteen subjects underwent colonoscopy with measurements of the ICV pressures after intubation of the ICV with a colonoscope. Initial baseline readings showed no statistical difference in the pressures of the TI and ICV, between subjects with positive lactulose breath tests and normal lactulose breath tests. The average peak ICV pressure during air insufflation into the cecum in subjects with normal lactulose breath tests was significantly higher than cecal pressures during air insufflation (49.33 ± 7.99 mmHg vs 16.40 ± 2.14 mmHg, P = 0.0011). The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflations in subjects with normal lactulose breath tests was significantly higher (280.72% ± 43.29% vs 100% ± 0%, P = 0.0006). The average peak ICV pressure during air insufflation into the cecum in subjects with positive lactulose breath tests was not significantly different than cecal pressures during air insufflation 21.23 ± 3.52 mmHg vs 16.10 ± 3.39 mmHg. The average percentage difference of the area under the pressure curve of the ICV from the cecum during air insufflation was not significantly different 101.08% ± 7.96% vs 100% ± 0%. The total symptom score for subjects with normal lactulose breath tests and subjects with positive lactulose breath tests was not statistically different (13.30 ± 4.09 vs 24.14 ± 6.58). The ICV peak pressures during air insufflations were significantly higher in subjects with normal lactulose breath tests than in subjects with positive lactulose breath tests (P = 0.005). The average percent difference of the area under the pressure curve in the ICV from cecum was significantly higher in subjects with normal lactulose breath tests than in subjects with positive lactulose breath tests (P = 0.0012). Individuals with positive lactulose breath tests demonstrated symptom scores which were significantly higher for the following symptoms: not able to finish normal sized meal, feeling excessively full after meals, loss of appetite and bloating.

Compared to normal, subjects with a positive lactulose breath test have a defective ICV cecal distension reflex. These subjects also more commonly have higher symptom scores.

Each year, millions of dogs worldwide are abandoned by their owners, relinquished to animal shelters, and euthanised because of behaviour problems. Nutrition is rarely considered as one of the possible contributing factors of problem behaviour. This contribution presents an overview of current knowledge on the influence of nutrition on canine behaviour and explores the underlying mechanisms by which diet may affect behaviour in animals. Behaviour is regulated by neurotransmitters and hormones, and changes in the availability of their precursors may influence behaviour. Tryptophan, the precursor of serotonin, may affect the incidence of aggression, self-mutilation and stress resistance. The latter may also be influenced by dietary tyrosine, a precursor to catecholamines. As diet composition, nutrient availability and nutrient interactions affect the availability of these precursors in the brain, behaviour or stress resistance may be affected. PUFA, especially DHA, have an important role as structural constituents in brain development, and dietary supply of n-3 and n-6 PUFA could modify aspects of the dopaminergic and serotonergic system and, consequently, cognitive performance and behaviour. Finally, persistent feeding motivation between meals can increase stereotyped behaviour and aggression and decrease resting time. This feeding motivation may be altered by dietary fibre content and source. At present, few studies have been conducted to evaluate the role of nutrition in canine (problem) behaviour through the above mentioned mechanisms. Studies that explore this relationship may help to improve the welfare of dogs and their owners.

The neuroanatomy of the ileocecal valve (ICV) is poorly understood. A better understanding of this important functional component of the gastrointestinal tract would enable surgeons to reconstruct an effective valve following surgical resection of the ICV. ICVs were examined in young pigs (N = 5) using frontal and transverse paraffin embedded and frozen sections. Hematoxylin+Eosin (H+E) staining, acetylcholinesterase (AchE), and NADPH-diaphorase (NADPH-d) histochemistry and protein gene product 9.5 (PGP 9.5) and C-kit immunohistochemistry were performed. The H+E staining revealed that the ICV consists of three muscle layers: an external circular muscle layer continuous with that of the ileal circular muscle layer, an inner circular muscle layer continuous with that of the cecal circular muscle layer, and a single longitudinal muscle layer, which appears to be secondary to a fusion of the ileal and cecal longitudinal muscle layers. The AchE, NADPH-d, and PGP 9.5 staining revealed two distinct coaxial myenteric plexuses, together with superficial and deep submucosal plexuses. The C-kit immunostaining showed a continuous myenteric ICC network within the ICV. The structure of the neuromuscular components within the ICV suggests that the valve is a result of a simple intussusception of the terminal ileum into the cecum. This knowledge may help surgeons in their future attempts at reconstructing more anatomically and functionally suitable ICVs following surgical resection of native ICVs.

The relationships between ileocolonic motor patterns and flow have not been defined in humans. Utilizing simultaneous ileocolonic manometry and scintiscanning, we aimed to examine this relationship and test the hypotheses that ileal propagating sequences (PSs) underlie caecal filling, that caecal filling is a stimulus for proximal colonic PSs and that the ileocolonic junction (ICJ) regulates flow between the small and large bowel. In six healthy volunteers, a 5-m-long nasocolonic manometry catheter was positioned such that 16 recording sites, spaced at 7.5-cm intervals, spanned the ileum and proximal colon. Subjects were positioned under a gamma camera 30 MBq of (99m)Tc sulphur colloid was instilled, 22.5 cm proximal to the ICJ. Isotopic images were recorded (10 s per frame) and synchronized with the manometric trace. We identified 171 ileal PSs, 47 caecal PSs and 117 discrete episodes of caecal filling. Of the 117 episodes of caecal filling, 72% were associated temporally with ileal PSs. Conversely, 87% of ileal PSs were associated with caecal filling. Of the PSs originating in the caecum, 90% were temporally associated with caecal filling. We conclude that ileal PSs are highly propulsive and are the major determinant of episodic caecal filling and that caecal filling may be a major stimulus for caecal propagating sequences.

The human ileocolonic sphincter (ICS) develops a sustained tone mainly due to propagated and not propagated phasic motor activity. The ileocaecocolonic segment is also able to behave, yet uncommonly, as a synchronized segment involving propagated contractions originating from the ileum and migrating to the proximal colon. The ICS motor activity alone has a limited role towards forward flow. On the contrary, the functional entity corresponding to the distal ileum and the ICS provides a clearance mechanism for reflux of colonic contents into the small intestine. The presence of short chain fatty acids (SCFA) in the distal ileum, sensed either by endocrine cells or chemo-sensitive vagal afferents, is an important actor in triggering this clearance mechanism. The ICS tone is in part myogenic but a neuronal nitrergic component is also involved. Reflex excitatory and inhibitory responses of the ICS originating from ileal or colonic distension involve primarily spinal nitrergic and adrenergic pathways.

Ileal infusion of cecocolonic contents, used to mimick reflux, enhanced terminal ileal motility, increasing the frequencies of prolonged propagated contractions (PPC) and discrete clustered contractions (DCC). Because the reflux rate in dogs and humans is marginal, the relationship of these motor patterns to reflux remained putative. In six conscious pigs, the ileal pH, used to indicate reflux event, was measured 10 and 5 cm proximal to the ileocecal sphincter (ICS). Ileal motility was evaluated with three strain gauges 15, 10, and 5 cm proximal to the ICS. Ileal pH dips were observed about eight times per hour in the fasting or fed state, and 46% of the pH dips were preceded by a retrograde contraction. During pH dips, frequency of ileal contractions not classified as PPC or DCC was significantly increased. Of the PPC 52% occurred immediately after the start of the dip and might act as a clearance mechanism because dips associated with PPC were of smaller amplitude and duration than those not associated with PPC. Most DCC also occurred during pH dips but their delay to the onset of the dip was longer. The pig presents frequent cecoileal reflux events associated with ileal motor patterns, some of them might facilitate reflux, whereas others act as a clearance mechanism.

Short-chain fatty acids (SCFAs) reportedly have a trophic effect on the small intestine. However, it is unclear if this is a local or primarily systemic effect. Loss of the ileocolonic junction (ICJ) may result in increased SCFAs and bacteria in the small intestine from colonic reflux. Our aim was to evaluate the effect of bypass of the ICJ on intestinal SCFA content and postresection adaptation.

Thirty dogs were studied: transection control (TC, n = 10), distal resection of 50% intestine (DR, n = 10), and distal resection with bypass of ICJ (DRBP, n = 10). Animals were killed at 4 and 12 weeks. Luminal SCFAs and bacteria and adaptation of the small intestine were evaluated.

Caloric intake was significantly less in the two resected groups (67 +/- 3 DR and 63 +/- 3, DRBP vs 78 +/- 5 kcal/kg/d TC, p < .05). Body weight and albumin levels were decreased at 12 weeks but were similar between the resected groups (81% +/- 3% and 74% +/- 6% initial and 1.9 +/- 0.1 and 2.1 +/- 0.2 g/dL, DR and DRBP, respectively). Steatorrhea was present for 12 weeks after resection and was greater after DRBP (14.2% +/- 3.8% vs 8.6% +/- 1.9% at 4 weeks and 13.6% +/- 2.5% vs 6.7% +/- 0.6% at 12 weeks, p < .05). Bypassed animals had elevated intraluminal SCFA content (3126 +/- 1094 vs 1791 +/- 538 DR and 1600 +/- 446 micrograms/mL TC, p < .05) and anaerobic bacterial counts (100% vs 50% and 44%, respectively). Tissue inflammation and myeloperoxidase activity were similar. Small intestinal length (174 +/- 10 and 180 +/- 10 cm) and circumference (5.2 +/- 0.4 and 5.2 +/- 0.3 cm) increased to a similar extent in both resected groups at 12 weeks. Thickness of mucosa (1939 +/- 162 vs 1662 +/- 162 microns) and muscle (865 +/- 45 vs 978 +/- 79 microns) layers were similar after DR and DRBP.

(1) Bypass of the ICJ after distal resection results in increased growth of anaerobic bacteria and luminal SCFA and is associated with more marked steatorrhea. (2) Bypass of the ICJ does not influence structural adaptation of the small intestine. (3) These findings do not support a local trophic effect for SCFA.

The aim was to determine the effect of intraluminal acetic acid and proximal colonic distension on canine ileocolonic sphincter pressure, ileal motility, and coloileal reflux. In six conscious dogs with an isolated ileocolonic loop, basal pressure of the ileocolonic sphincter was similar during ileal perfusion with 100 mM acetic acid at 1 ml/min (mean +/- SEM = 18 +/- 0.4 mm Hg) and with saline (18 +/- 0.5 mm Hg; P = 0.81). Discrete clustered ileal contractions were more frequent with acetic acid, however, and when they propagated across the sphincter, sphincter pressure increased from 18 +/- 0.4 mm Hg to 36 +/- 1.3 mm Hg (P = 0.002). Sphincter pressure was also greater during colonic perfusion with acetic acid (32 +/- 0.7 mm Hg) than during ileal perfusion with acetic acid or saline (P less than 0.017). Moreover, sphincter pressure gradually increased as the colon was distended with saline (slope = 0.8 mm Hg/cm H2O, P less than 0.017) or acetic acid (slope = 0.5 mm Hg/cm H2O, P less than 0.017), but the increase did not prevent coloileal reflux. In conclusion, ileal clustered contractions, colonic perfusion of acetic acid, and colonic distension all increased canine ileocolonic sphincter pressure.

The association between emotion and gastrointestinal dysfunction has been postulated for centuries, and all practicing clinicians have anecdotal experience of the association between stress and irritable bowel syndrome (IBS). However, definite proof of an etiologic link between stress and gut motor dysfunction remains elusive, despite the large number of publications on this topic. A critical appraisal of methodology, use of controls, data interpretation, and significance of findings in the published literature is necessary to assess the present state of knowledge and to develop more meaningful studies in the future. This review attempts to summarize these perspectives.