Early versus on-demand nasoenteric tube feeding in acute pancreatitis

BACKGROUND

Early enteral feeding through a nasoenteric feeding tube is often used in patients with severe acute pancreatitis to prevent gut-derived infections, but evidence to support this strategy is limited. We conducted a multicenter, randomized trial comparing early nasoenteric tube feeding with an oral diet at 72 hours after presentation to the emergency department in patients with acute pancreatitis.

METHODS

We enrolled patients with acute pancreatitis who were at high risk for complications on the basis of an Acute Physiology and Chronic Health Evaluation II score of 8 or higher (on a scale of 0 to 71, with higher scores indicating more severe disease), an Imrie or modified Glasgow score of 3 or higher (on a scale of 0 to 8, with higher scores indicating more severe disease), or a serum C-reactive protein level of more than 150 mg per liter. Patients were randomly assigned to nasoenteric tube feeding within 24 hours after randomization (early group) or to an oral diet initiated 72 hours after presentation (on-demand group), with tube feeding provided if the oral diet was not tolerated. The primary end point was a composite of major infection (infected pancreatic necrosis, bacteremia, or pneumonia) or death during 6 months of follow-up.

RESULTS

A total of 208 patients were enrolled at 19 Dutch hospitals. The primary end point occurred in 30 of 101 patients (30%) in the early group and in 28 of 104 (27%) in the on-demand group (risk ratio, 1.07; 95% confidence interval, 0.79 to 1.44; P=0.76). There were no significant differences between the early group and the on-demand group in the rate of major infection (25% and 26%, respectively; P=0.87) or death (11% and 7%, respectively; P=0.33). In the on-demand group, 72 patients (69%) tolerated an oral diet and did not require tube feeding.

CONCLUSIONS

This trial did not show the superiority of early nasoenteric tube feeding, as compared with an oral diet after 72 hours, in reducing the rate of infection or death in patients with acute pancreatitis at high risk for complications. (Funded by the Netherlands Organization for Health Research and Development and others; PYTHON Current Controlled Trials number, ISRCTN18170985.).

Pancreatitis, very early compared with normal start of enteral feeding (PYTHON trial): design and rationale of a randomised controlled multicenter trial

BACKGROUND

In predicted severe acute pancreatitis, infections have a negative effect on clinical outcome. A start of enteral nutrition (EN) within 24 hours of onset may reduce the number of infections as compared to the current practice of starting an oral diet and EN if necessary at 3-4 days after admission.

METHODS/DESIGN

The PYTHON trial is a randomised controlled, parallel-group, superiority multicenter trial. Patients with predicted severe acute pancreatitis (Imrie-score ≥ 3 or APACHE-II score ≥ 8 or CRP > 150 mg/L) will be randomised to EN within 24 hours or an oral diet and EN if necessary, after 72 hours after hospital admission.During a 3-year period, 208 patients will be enrolled from 20 hospitals of the Dutch Pancreatitis Study Group. The primary endpoint is a composite of mortality or infections (bacteraemia, infected pancreatic or peripancreatic necrosis, pneumonia) during hospital stay or within 6 months following randomisation. Secondary endpoints include other major morbidity (e.g. new onset organ failure, need for intervention), intolerance of enteral feeding and total costs from a societal perspective.

DISCUSSION

The PYTHON trial is designed to show that a very early (< 24 h) start of EN reduces the combined endpoint of mortality or infections as compared to the current practice of an oral diet and EN if necessary at around 72 hours after admission for predicted severe acute pancreatitis.

TRIAL REGISTRATION

ISRCTN: ISRCTN18170985.

Gastrointestinal-specific anxiety: an important factor for severity of GI symptoms and quality of life in IBS

BACKGROUND

Gastrointestinal (GI)-specific anxiety (GSA) has been proposed to influence symptom severity and quality of life (QOL) in patients with irritable bowel syndrome (IBS). The Visceral Sensitivity Index (VSI) is a recently developed, reliable and valid measure of GSA. Our aim was to evaluate the association between GSA, GI symptom severity, and QOL in IBS patients.

METHODS

Sixty healthy subjects and 306 patients fulfilling the Rome II criteria for IBS were studied. Demographic and disease-related factors were assessed. Patients completed VSI and GI Symptom Rating Scale (GSRS) and questionnaires to determine psychological symptom severity (Hospital Anxiety and Depression Scale), QOL (Short form 36), and presence of functional GI disorders (Rome II Modular Questionnaire).

KEY RESULTS

Compared with healthy subjects, patients with IBS had more severe GSA (34.7 +/- 16.9 vs. 2.2 +/- 4.4 [mean +/- standard deviation]; P < 0.0001). In the IBS group, more severe GSA was seen in patients with more severe GI symptoms (P < 0.0001), general anxiety (P < 0.0001) and depression (P < 0.0001), and with lower socioeconomic status (P < 0.05). In a regression analysis, GSA was the strongest predictor for GI symptom severity (GSRS total score), followed by number of Rome II diagnoses, presence of meal-related IBS symptoms, and gender (R(2) = 0.34). Gastrointestinal-specific anxiety was also, together with general anxiety, depression, socioeconomic status, and gender, found to be independently associated with mental QOL (R(2) = 0.62).

CONCLUSIONS & INFERENCES

Gastrointestinal-specific anxiety seems to be an important factor for GI symptom severity and QOL in patients with IBS.

Neurophysiological evaluation of healthy human anorectal sensation

Patients with functional gastrointestinal disorders often demonstrate abnormal visceral sensation. Currently, rectal sensation is assessed by manual balloon distension or barostat. However, neither test is adaptable for use in the neurophysiological characterization of visceral afferent pathways by sensory evoked potentials. The aim of this study was to assess the reproducibility and quality of sensation evoked by electrical stimulation (ES) and rapid balloon distension (RBD) in the anorectum and to apply the optimum stimulus to examine the visceral afferent pathway with rectal evoked potentials. Healthy subjects (n = 8, median age 33 yr) were studied on three separate occasions. Variability, tolerance, and stimulus characteristics were assessed with each technique. Overall ES consistently invoked pain and was chosen for measuring rectal evoked potential whereas RBD in all cases induced the strong urge to defecate. Rectal intraclass correlation coefficient (ICC) for ES and RBD (0.82 and 0.72, respectively) demonstrated good reproducibility at pain/maximum tolerated volume but not at sensory threshold. Only sphincter ICC for ES at pain showed acceptable between-study reproducibility (ICC 0.79). Within studies ICC was good (>0.6) for anorectal ES and RBD at both levels of sensation. All subjects reported significantly more unpleasantness during RBD than ES (P < 0.01). This study demonstrates that ES and RBD are similarly reproducible. However, the sensations experienced with each technique differed markedly, probably reflecting differences in peripheral and/or central processing of the sensory input. This is of relevance in interpreting findings of neuroimaging studies of anorectal sensation and may provide insight into the physiological characteristics of visceral afferent pathways in health and disease.

Effects of regular physical activity on defecation pattern in middle-aged patients complaining of chronic constipation

OBJECTIVE

It is not well known whether physical activity (PA) is useful in the management of patients complaining of constipation. The aim of this study was to test the influence of regular PA on colonic transit time and defecation in middle-aged inactive patients suffering from chronic idiopathic constipation.

MATERIAL AND METHODS

Forty-three subjects (> 45 years) were randomly divided into group A (n = 18, 16 F, 2 M) and group B (n = 25, 20 F, 5 M). Group A subjects maintained their normal lifestyle during 12 weeks, followed by a 12-week PA programme. Group B performed a 12-week PA programme after randomization. PA comprised 30 min of brisk walking and a daily 11-min home-based programme. Both groups received dietary advice. Colonic transit time was measured using a radiographic multiple marker single film technique.

RESULTS

Despite dietary advice, mean fibre and fluid intake did not change. In group B a significant reduction in 3 out of 4 of the Rome I criteria for constipation was observed, i.e. percentage of incomplete defecations, percentage of defecations requiring straining and percentage of hard stools (p < 0.05). As a consequence, the number of fulfilled Rome criteria for constipation decreased (2.7 to 1.7; p < 0.05). Furthermore, the rectosigmoid and total colonic transit time decreased (17.5 to 9.6 h and 79.2 to 58.4 h, respectively; p < 0.05). After PA the number of fulfilled Rome criteria also decreased in group A (2.6 to 1.7; p < 0.05).

CONCLUSIONS

In middle-aged inactive subjects with symptoms of chronic constipation, it is advisable to promote regular physical activity since it improves both the defecation pattern and rectosigmoid or total colonic transit time.

Characterization of the receptors involved in the 5-HT-induced excitation of canine antral longitudinal muscle

1. We aimed to characterize the 5-HT receptors involved in the 5-HT-induced effect on electrically induced contractions of dog antrum longitudinal muscle in vitro. 2. In the presence of L-NOARG (0.1 mM), electrical field stimulation (EFS) induced atropine- and tetrodotoxin-sensitive contractions. Tetrodotoxin or atropine left any agonist tested ineffective. These EFS-induced contractions were on average enhanced by 5-HT (0.3 microM), however, pronounced variation in the response to 5-HT was observed. There were non-significant trends of the selective 5-HT3 receptor antagonist granisetron (1 microM), and methysergide (1 microM; preventing interactions of 5-HT with 5-HT1, 5-HT2, 5-ht5, 5-HT6 and 5-HT7 receptors) to increase the response to 5-HT. The selective 5-HT4 receptor antagonist GR 113808 (0.1 microM) displayed a non-significant trend to inhibit the 5-HT-induced increase. 3. Combination experiments with methysergide (1 microM), granisetron (1 microM) and GR 113808 (0.1 microM) revealed that the 5-HT (0.3 microM)-induced response consisted of (1) an excitatory component blocked by GR 113808, (2) excitatory and inhibitory components both blocked by methysergide. 4. The selective 5-HT4 receptor agonist prucalopride (0.3 microM) increased EFS-induced contractions, an effect prevented by GR 113808 (0.1 microM). 5. The increase of EFS-induced contractions by the preferential 5-HT2 receptor agonist alpha-Me-5-HT (0.3 microM) was antagonized by 5-HT2B receptor antagonists. 6. The 5-HT1/5-HT7 receptor agonist 5-carboxamidotryptamine (5-CT; 0.3 microM) inhibited EFS-induced contractions. This was prevented by methysergide (1 microM), the 5-HT7 receptor antagonist mesulergine (0.3 microM) and the selective 5-HT7 receptor antagonist SB-269970 (0.3 microM). 7. In the presence of GR 113808 (0.1 microM), alpha-Me-5-HT (1 microM) increased EFS-induced contractions. The 5-HT (0.3 microM)-induced inhibition of the stimulation by alpha-Me-5-HT was prevented by SB-269970 (0.3 microM). 8. In conclusion, dog antral longitudinal muscle is endowed with (1) excitatory neuronal 5-HT4 receptors and 5-HT2B receptors and (2) inhibitory smooth muscle 5-HT7 receptors.

Effects of intraduodenal bile on interdigestive gastrointestinal and gallbladder motility in healthy subjects

BACKGROUND/AIMS

The enterohepatic circulation of bile acids is related to normal inter-digestive gastrointestinal motility, with the gut peptide motilin also being involved. This study aimed to investigate the effect of intraduodenal artificial bile infusion on antroduodenal and gallbladder motility so as to further elucidate the controlling factors.

METHODS

Twelve fasting, healthy male volunteers received artificial bile (80 mol% bile acids; 15 mol% phospholipids; 5 mol% cholesterol) or placebo (saline) intraduodenally for 10 min starting 30 min after the end of phase III, according to a double-blind, randomised, cross-over design. Antroduodenal motility, gallbladder volumes, and plasma motilin levels were measured. All values are means +/- SEM.

RESULTS

The interval between infusion and the subsequent phase III, as well as the origin of this phase III were not significantly different between bile and saline. Antral pressure waves were significantly more frequent during and immediately after bile infusion compared with saline infusion (p < 0.05). The duration of phase I following infusion was significantly longer after bile (24.8 +/- 3.7 min) than after saline infusion (13.1 +/- 1.7 min; p < 0.05). The mean gallbladder volume tended to increase in the hours following bile infusion, but to decrease after saline infusion (p = 0.06). Plasma motilin increased after bile and saline infusion in an almost identical way.

CONCLUSION

This study provides no clear evidence for a role of intraduodenal artificial bile (i.e. its main constituents) in the regulation of migrating motor complex cycling or feedback inhibition of inter-digestive gallbladder emptying.

Interdigestive gallbladder emptying, antroduodenal motility, and motilin release patterns are altered in cholesterol gallstone patients

The role of interdigestive gallbladder emptying in gallstone formation is unknown. In fasting healthy subjects, gallbladder emptying is associated with antral phase III of the migrating motor complex (MMC) and high plasma motilin. Therefore, gallbladder volumes and motilin levels were measured during 13 MMC cycles in 10 cholesterol gallstone patients and compared with 20 MMC cycles in 10 healthy subjects. MMC cycle length was longer in gallstone patients than in healthy subjects (158.2 +/- 17.0 vs 105.5 +/- 10.4 min, respectively; P < 0.05), due to longer phase I (39.8 +/- 5.7 vs 17.2 +/- 3.7 min, respectively; P < 0.05). In contrast to healthy subjects, gallstone patients had no significant fluctuations of gallbladder volume during the MMC cycle, and motilin concentrations were not different in MMC cycles with phase III originating in antrum or duodenum. During MMC cycles with phase III originating in the duodenum, motilin levels were twice as high in gallstone patients as in healthy subjects (P < 0.002). In conclusion, cholesterol gallstone patients have an abnormal MMC and motilin release pattern. Their interdigestive gallbladder emptying is reduced and dissociated from the MMC. These disturbances may contribute to gallstone formation.

Functional results and visceral perception after ileo neo-rectal anastomosis in patients: a pilot study

INTRODUCTION

To reduce pouch related complications after restorative proctocolectomy, an alternative procedure was developed, the ileo neo-rectal anastomosis (INRA). This technique consists of rectal mucosa replacement by ileal mucosa and straight ileorectal anastomosis. Our study provides a detailed description of the functional results after INRA.

PATIENTS AND METHODS

Eleven patients underwent an INRA procedure with a temporary ileostomy. Anorectal function tests were performed two months prior to and six and 12 months after closure of the ileostomy and comprised: anal manometry, ultrasound examination, rectal balloon distension, and transmucosal electrical nerve stimulation (TENS). Function was subsequently related to the histopathology of rectal biopsy samples.

RESULTS

Median stool frequency decreased from 15/24 hours (10-25) to 6/24 hours (4-11) at one year. All patients reported full continence. Anal sensibility, and resting and squeeze pressures did not change after INRA. Rectal compliance decreased (2.1 (0.7-2.8) v 1.5 (0.4-2.2) and 1.4 (0.8-3.7) ml/mm Hg (p=0.03)) but the maximum tolerated volume increased (70 (50-118) v 96 (39-176) (NS) and 122 (56-185) ml (p=0.03)). Decreasing rectal sensitivity was found: the maximum tolerated pressure increased (14 (8-24) v 22 (8-34) (NS) and 26 (14-40) (p=0.02)) and the rectal threshold for TENS displayed a similar tendency. All patients displayed a low grade chronic inflammatory infiltrate in neorectal biopsy samples before closure of the ileostomy, with no change during follow up.

CONCLUSIONS

The technique of INRA provides a safe alternative for restorative surgery. Stool frequency after INRA improves with time and seems to be related to decreasing sensitivity and not to histopathological changes in the neorectum. Furthermore, after the INRA procedure, all patients reported full continence.

5-HT(4) receptors mediating enhancement of contractility in canine stomach; an in vitro and in vivo study

We aimed to study 5-HT(4) receptors in canine stomach contractility both in vivo and in vitro. In anaesthetized Beagle dogs, the selective 5-HT(4) receptor agonist prucalopride (i.v.) induced dose-dependent tonic stomach contractions under isobaric conditions, an effect that was antagonized by the selective 5-HT(4) receptor antagonist GR 125487 (10 microg kg(-1), i.v.). Electrical field stimulation (EFS) of corpus longitudinal muscle strips resulted in atropine- and tetrodotoxin-sensitive contractions (L-NOARG (0.1 mM) present in all organ bath solutions). Prucalopride increased these contractions (maximal response after single-dose addition (0.3 microM): 165% of initial value, or after cumulative addition: 188%). In the presence of methysergide (3 microM), 5-HT also increased EFS-contractions (after single-dose addition (0.3 microM): increase to 192%, after cumulative addition: 148%). The selective 5-HT(4) receptor antagonists GR 113808 (0.1 microM) or GR 125487 (10 nM) antagonized the prucalopride (0.3 microM)-induced contraction increments. When EFS-induced contractions were blocked by atropine or tetrodotoxin, prucalopride was ineffective. In the presence of methysergide (3 microM), the contraction increases to 5-HT (0.3 microM) were prevented by GR 113808 (0.1 microM). The prucalopride curve (pEC(50) 7.9) was shifted in parallel to the right by GR 113808 3 nM (pA(2) 9.4). In the presence of methysergide (3 microM), the curve to 5-HT (pEC(50) 8.1) was competitively antagonized by GR 113808, yielding a Schild slope of 0.8+/-0.2 (pK(B) of 9.1 with unit Schild slope). In corpus circular muscle strips, the prucalopride (0.3 microM)-induced augmentation of EFS-contractions (258%) was also prevented by GR 113808 (0.1 microM) (124%). In conclusion, the effects of 5-HT(4) receptor agonists on proximal stomach motor activity in vivo can be explained by an effect on 5-HT(4) receptors on cholinergic nerves within the gastric muscle wall.

Prolonged recording of oesophageal and lower oesophageal sphincter pressure using a portable water-perfused manometric system

The aim of our study was to investigate the recording fidelity of a water-perfused micromanometric catheter with incorporated sleeve combined with a newly developed portable water-perfused manometric system for pharyngeal, oesophageal and lower oesophageal sphincter (LOS) pressure recording. The system's performance was assessed in prolonged recordings in ambulant gastro-oesophageal reflux disease (GORD) patients. Eighty 24-h studies in GORD patients, carried out with the perfused portable manometric system, were evaluated. Twelve of these recordings were analysed in detail in order to compare oesophageal and LOS motor patterns with those described previously. Paired 2-h manometric recordings of the pharynx, oesophagus, LOS and stomach, using the new system and a conventional perfused stationary manometric system, were performed in eight healthy subjects. With the portable manometric system oesophageal contractions, transient LOS relaxations, swallow-associated prolonged LOS relaxations and LOS pressures were recorded with equal fidelity to the conventional manometric system. Recordings obtained with the portable system showed meal-related and diurnal variations in oesophageal and LOS variables that were similar to these found in studies using conventional equipment. The new manometric system, consisting of a perfused micromanometric catheter with incorporated sleeve and a portable perfusion system, enables prolonged studies on oesophageal and LOS motor patterns in ambulant subjects.

The ileo neorectal anastomosis: an experimental study on development of the surgical technique and theoretical background

OBJECTIVE

The keystones of surgical treatment of ulcerative colitis and familial adenomatous polyposis are resection of the diseased colon with either an ileostomy or restoration of oro-anal continuity with an ileo-anal pouch. The ileo pouch anal anastomosis however, has a 15-35% pouch-related complication rate, 10% failure rate and is accompanied by an unpredictable functional outcome. In order to reduce these unfavourable rates and to improve functional results an alternative surgical technique, the ileo neorectal anastomosis (INRA), was developed experimentally.

MATERIALS AND METHODS

In an experimental study 12 Yorkshire-Dutch landpigs had a subtotal colectomy and rectal mucosectomy. Subsequently a vascularized ileal mucosa sling was created and transposed on to the denuded rectal muscular cuff in eight. In another four animals a non-vascularized mucosa sling was transposed. The covering ileostomy was closed after 3 weeks. Repeated endoscopies, histological examinations of mucosal biopsies and rectal compliance measurements were carried out to evaluate the functional result of the neorectum.

RESULTS

The surgical procedure of the INRA was technically successful in this animal study. Repeated endoscopy and histology showed complete ileal mucosa ingrowth in the neorectum without severe fibrosis in the group of animals with a vascularized sling. At follow up after 1 year no colonic metaplasia had occurred. Measurements of the neorectal reservoirs in the group of animals with a vascularized INRA procedure showed a median 'maximum tolerated volume' of 338 ml (range 300-410 ml).

CONCLUSION

The INRA is technically feasible and reproducible. The histologically proven survival of the vascularized ileal mucosa and development of a compliant neorectal reservoir make the INRA an interesting alternative restorative procedure. Avoidance of the pouch-related complications of the ileo pouch anal anastomosis by this procedure might herald a new era of restorative surgery.

Potential benefits and hazards of physical activity and exercise on the gastrointestinal tract

This review describes the current state of knowledge on the hazards of exercise and the potential benefits of physical activity on the gastrointestinal tract. In particular, acute strenuous exercise may provoke gastrointestinal symptoms such as heartburn or diarrhoea. A substantial part (20-50%) of endurance athletes are hampered by these symptoms which may deter them from participation in training and competitive events. Nevertheless, these acute symptoms are transient and do not hamper the athlete's health in the long term. The only exception is repeated gastrointestinal bleeding during training and competition, which in the long term may occasionally lead to iron deficiency and anaemia. In contrast, repetitive exercise periods at a relatively low intensity may have protective effects on the gastrointestinal tract. There is strong evidence that physical activity reduces the risk of colon cancer by up to 50%. Less convincing evidence exists for cholelithiasis and constipation. Physical activity may reduce the risk of diverticulosis, gastrointestinal haemorrhage, and inflammatory bowel disease although this cannot be substantiated firmly. Up to now, underlying mechanisms are poorly understood although decreased gastrointestinal blood flow, neuro-immuno-endocrine alterations, increased gastrointestinal motility, and mechanical bouncing during exercise are postulated. Future research on exercise associated digestive processes should give more insight into the relationship between physical activity and the function of the gastrointestinal tract.

Obstructive jaundice, bacterial translocation and interdigestive small-bowel motility in rats

BACKGROUND/AIMS

Translocation of gut bacteria occurs in obstructive jaundice, the underlying mechanisms are unclear. We designed this experimental study to investigate the association between interdigestive motility and the pathogenesis of bacterial translocation during biliary obstruction.

METHODS

Rats were fitted with jejunal myoelectrodes for the measurement of the interdigestive migrating motor complex (MMC) and with two cannulas in the proximal common bile duct (CBD) for exteriorization of biliary flow. This allowed measurement of MMCs under control conditions with an intact enterohepatic circulation and during 3 days of CBD obstruction without surgical intervention. Mesenteric lymph nodes, liver, spleen and segments of the duodenum, the jejunum and the caecum were removed for microbial culturing.

RESULTS

The MMC cycle length increased from 17.3 min before CBD obstruction to 31.9, 34.1, and 25.3 min on days 1, 2 and 3, respectively, after CBD obstruction (p < 0.05 for all days). Bacterial levels in the jejunum were significantly higher in CBD-obstructed rats than in control rats. The translocation incidence was significantly higher in rats with CBD obstruction (6/8) than in control rats (1/8). The bacterial levels in the jejunum correlated significantly with the MMC cycle length (r = 0.60, p <0.05).

CONCLUSION

Experimental biliary obstruction is associated with disturbance of MMCs, small-bowel bacterial overgrowth and increased bacterial translocation.

A standardised and reproducible model of intraabdominal infection and abscess formation in rats

OBJECTIVE

To develop a standardised and reproducible model of intra-abdominal infection and abscess formation in rats.

DESIGN

Experimental study.

SETTING

University hospital, The Netherlands.

SUBJECTS

36 adult male Wistar rats.

INTERVENTIONS

In 32 rats, peritonitis was produced using two different concentrations of Escherichia coli (E. coli) and Bacteroides fragilis (B. fragilis) incorporated in fibrin clots (E. coii 1 x 10(5) colony forming units (CFU)/ml or 1 x 10(8) CFU/ml, B. fragilis: 1 x 10(8) CFU/ml). Four rats with fibrin clots without bacteria served as uninfected controls.

MAIN OUTCOME MEASUREMENTS

Macroscopy and bacterial counts in peritoneal fluid, blood, and fibrin clots after 24 hours, 4 days, 7 days, and 4 weeks.

RESULTS

Macroscopically, there were signs of intra-abdominal infection and abscesses. With the higher starting concentration of E. coli, macroscopic signs were more pronounced and in nearly all rats bacterial counts in peritoneal fluid and fibrin clots showed persistently high numbers of E. coli and B. fragilis for at least 7 days (E. coli = 2 x 10(3) to 1 x 10(6) CFU/ml and 5 x 10(7) to 9 x 10(8) CFU/clot; B. fragilis = 1 x 10(3) to 1 x 10(6) CFU/ml and 5 x 10(7) to 6 x 10(8) CFU/clot).

CONCLUSION

This standardised and reproducible model of intra-abdominal infection and abscess formation seems well suited for further use and development in experiments on the pathophysiology of intra-abdominal infection and abscesses.

5-HT(4) receptors on cholinergic nerves involved in contractility of canine and human large intestine longitudinal muscle

5-HT(4) receptors mediate circular muscle relaxation in both human and canine large intestine, but this phenomenon alone can not explain the improvement in colonic motility induced by selective 5-HT(4) receptor agonists in vivo. We set out to characterize 5-HT(4) receptor-mediated effects in longitudinal muscle strips of canine and human large intestine. Electrical field stimulation (EFS) was applied providing submaximal isotonic contractions. L-NOARG (0.1 mM) was continuously present in the organ bath to preclude nitric oxide-induced relaxation to EFS. The selective 5-HT(4) receptor agonist prucalopride (0.3 microM) enhanced EFS-evoked contractions, that were antagonized in both preparations by the selective 5-HT(4) receptor antagonist GR 113808 (0.1 microM). The prucalopride-induced increase was present in canine ascending and descending colon, but absent in rectum. Regional differences in response to prucalopride were not observed in human ascending and sigmoid colon and rectum. Incubation with atropine (1 microM) or tetrodotoxin (0.3 microM) inhibited EFS-induced contractions, which were then unaffected by prucalopride (0.3 microM) in both tissues. In the presence of methysergide (3 microM; both tissues) and granisetron (0.3 microM; only human tissues), 5-HT (0.3 microM) enhanced EFS-induced contractions, an effect that was antagonized by GR 113808 (0.1 microM). In the presence of atropine or tetrodotoxin, EFS-induced contractions were inhibited, leaving 5-HT (0.3 microM) ineffective in both preparations. This study demonstrates for the first time that in human and canine large intestine, 5-HT(4) receptors are located on cholinergic neurones, presumably mediating facilitating release of acetylcholine, resulting in enhanced longitudinal muscle contractility. This study and previous circular muscle strip studies suggest that 5-HT(4) receptor agonism facilitates colonic propulsion via a coordinated combination of inhibition of circumferential resistance and enhancement of longitudinal muscle contractility.

Oral antibiotics as a novel therapy for arthritis: evidence for a beneficial effect of intestinal Escherichia coli

OBJECTIVE

The intestinal flora is thought to play an important role in regulation of immune responses. We investigated the effects of changing the intestinal flora on the course of adjuvant-induced arthritis (AIA) and on experimental autoimmune encephalomyelitis (EAE) by the use of oral antibiotics.

METHODS

Oral treatment with either vancomycin or vancomycin, tobramycin, and colistin was started after AIA and EAE induction. Clinical symptoms of AIA and EAE were monitored, and microbial analysis of ileal samples was performed.

RESULTS

Oral vancomycin treatment after disease induction significantly decreased clinical symptoms of AIA. Simultaneously, increased concentrations of Escherichia coli were detected in the distal ileum of vancomycin-treated rats. Ileal concentrations of E coli were inversely related to disease scores in rats with AIA. Coadministration of colistin/tobramycin to prevent the increase in E coli abrogated the beneficial effect of vancomycin on AIA. Vancomycin treatment also reduced the clinical symptoms of EAE.

CONCLUSION

We propose oral vancomycin as a novel therapeutic strategy in autoimmune diseases.

Megarectum in constipation

BACKGROUND

Faecal impaction is frequently observed in children with chronic constipation. The term megarectum is often used to describe this finding.

AIM

To evaluate rectal functioning and rectal measures in constipated children with a filled rectum, in order to define the terms faecal impaction, enlarged rectum, and megarectum.

METHODS

All children underwent radiological investigation, colonic transit time study, anorectal manometry, and rectal volume and rectal wall compliance measurements. Patients with faecal impaction were compared with controls, who had an empty rectum on digital rectal examination.

RESULTS

A total of 31 patients and six controls were included in the study. The mean duration of complaints was 4.2 years and all had faecal incontinence. The colonic transit times in the patients showed a distinct delay in the rectosigmoid segment. Anorectal manometry was not significantly different between patients and controls. The rectal width in patients was 0.68 and in controls 0.52 with an upper limit of 0.61. The pressure-volume curve in patients showed significant less relaxation at a distension of 50 ml. The slope of the curve (corresponding with rectal wall compliance) was comparable for patients and controls.

CONCLUSIONS

We suggest that faecal impaction is a filled rectum found on digital rectal examination; an enlarged rectum is defined by a rectopelvic ratio greater than 0.61; and megarectum is defined in those with significant abnormalities found with anorectal manometry, pressure-volume curves, or rectal compliance investigation. A diminished relaxation of the rectum on rectal distension could be the first sign of megarectum in children with chronic constipation.

Disturbed enterogastric inhibitory reflex after esophageal resection and narrow gastric tube reconstruction

BACKGROUND/AIMS

The gastric emptying pattern after esophageal resection and narrow gastric tube reconstruction is determined by multiple factors. One of the possible factors is a disruption in the neurohumoral enterogastric inhibitory reflex. The aim of the present study was to determine the possible alterations of this reflex after esophageal resection and narrow gastric tube reconstruction.

METHODS

Nine patients each underwent two gastric tube emptying studies, one without and one with high caloric duodenal tube feeding. The dual isotope scintigraphic data were corrected for subject movement, radionuclide decay, downscatter and gamma-ray attenuation.

RESULTS

The median gastric tube emptying rate of solid food was 57%/h (range 27-195). The median T(1/2) of liquid food was 67 (range 4->80) min. Both for solid and for liquid food, the gastric tube emptying patterns without and with duodenal tube feeding were not significantly different.

CONCLUSION

The neurohumoral enterogastric inhibitory reflex is disrupted after esophageal resection and narrow gastric tube reconstruction, which may contribute to disturbed gastric emptying.

An improved in vitro bioassay for the study of 5-HT(4) receptors in the human isolated large intestinal circular muscle

Recently, it was demonstrated that 5-HT induces relaxation of human colon circular muscle through activation of 5-HT(4) receptors and 5-HT(7) receptors. The aim of the current study was to develop a new in vitro bioassay of human colon that would facilitate the pharmacological analysis of 5-HT responses mediated solely by 5-HT(4) receptors. Contracting circular muscle strips with KCl (80 mM) yielded a stable contractile tension and, in contrast to muscarinic cholinoceptor agonists and histamine, a profound reduction of spontaneous contractility. This allowed the establishment of reproducible, fully-defined, agonist concentration-response curves by cumulative dosing. Under these conditions, 5-HT induced a concentration-dependent relaxation (pEC(50) 7.31, Hill slope 0.91). Neither methysergide (10 microM) nor granisetron (1 microM) affected the 5-HT-induced relaxation, suggesting that 5-HT(1), 5-HT(2), 5-HT(3), 5-ht(5), 5-HT(6) or 5-HT(7) receptors are not involved. The lack of effect of tetrodotoxin (0.3 microM) indicated a direct effect of 5-HT on the smooth muscle. The selective 5-HT(4) receptor antagonists GR 113808, GR 125487 and RS 39604 competitively antagonized the 5-HT-induced relaxation (pK(B) 9.43, 10.12 and 8.53, respectively). SB 204070 (1 nM) produced a rightward shift (pA(2) 10.34) and depression of the 5-HT curve. These affinity estimates are similar to those previously reported for 5-HT(4) receptors. The selective 5-HT(4) receptor agonists, prucalopride and R076186, induced relaxations (pEC(50) 7.50 and 7.57, respectively), that were blocked by GR 113808 (3 nM), yielding pA(2) estimates of 9.31 and 9.21, respectively. To summarise, in KCl (80 mM)-contracted muscle strips, 5-HT induces relaxation through activation of a homogeneous smooth muscle 5-HT(4) receptor population. This new bioassay allows the focused, pharmacological characterization of human colonic 5-HT(4) receptors in vitro.

Tonic motor activity of the narrow gastric tube used as an oesophageal substitute

OBJECTIVE

To assess the compliance, the existence of basal tone, the sensory response to distension, and the integrity of the neurohumoral enterogastric inhibitory reflex of the narrow gastric tube as an oesophageal substitute.

DESIGN

Explanatory experimental study.

SETTING

University hospital, The Netherlands.

PATIENTS

Eight patients after oesophagectomy, formation of a narrow gastric tube, and cervical gastro-oesophagostomy.

INTERVENTIONS

Measurements of intragastric tonic motor activity with a Barostat.

MAIN OUTCOME MEASUREMENTS

Compliance, sensations during stepwise pressure increments, and changes in tone induced by glucagon and intraduodenal feeding.

RESULTS

The compliance of the narrow gastric tube was found to be low (median 13.5 ml/mmHg (range 5-21)). Most of the patients perceived minimal sensation on distension. All patients had phasic tonic contractions during distension of the gastric tube. The median (range) relaxation after glucagon had been given intravenously was 14 ml (range 3-57) (p < 0.05). The tonic reaction to nutrients in the duodenum was not significant.

CONCLUSIONS

The compliance of the narrow gastric tube is low. Postprandial symptoms are not caused by distension of the proximal part of the narrow gastric tube. Basal gastric tone and phasic activity were at least partially restored over time after operation. The enterogastric inhibitory reflex is eliminated by oesophageal resection and reconstruction of a gastric tube.

[Gastrointestinal surgery and gastroenterology. VII. Proximal motility disorders in the digestive tract]

Dysphagia and chest pain are the two commonest symptoms of abnormalities of oesophageal motility. Dysphagia is to be distinguished into high or oropharyngeal and low or oesophageal dysphagia. Oropharyngeal dysphagia pertains to dysfunction of the pars cricopharyngea of the M. constrictor pharyngis inferior (M. cricopharyngeus), which is frequently associated with a Zenker diverticulum. Treatment consists of endoscopical or surgical myotomy and diverticulectomy. In achalasia there is incomplete relaxation of the lower esophageal sphincter with aperistalsis. The main treatment modalities are endoscopic pneumodilation and surgical myotomy of this sphincter. In dysphagia or non-cardiac chest pain spastic or hypocontractile abnormalities of the oesophageal motility can be involved, these are often difficult to treat. Disorders of gastric motility are mainly gastroparesis and functional dyspepsia. In diabetic gastroparesis, adequate monitoring of the blood sugar level is also necessary. New insights into the pathophysiology of functional dyspepsia concern abnormal visceral sensitivity and reduced adaptive relaxation of the stomach during intake of food.

The effect of coffee on gastric emptying and oro-caecal transit time

BACKGROUND

The consumption of coffee allegedly induces or aggravates gastrointestinal symptoms. In order to investigate the effect of coffee on gastrointestinal motility we studied the effect of coffee on gastric emptying and oro-caecal transit time.

METHODS

In a randomised, controlled, cross-over study gastric emptying and oro-caecal transit time were studied in 12 healthy volunteers, using applied potential tomography and lactulose hydrogen breath test, respectively. After 1 day of coffee abstinence and an overnight fast, coffee or the control drink (water) was drunk and 10 min thereafter a liquid nutrient meal was ingested together with lactulose. During 150 min, recordings were made with applied potential tomography and breath samples were taken every 5 min. Lag-phase duration and gastric half-emptying time were determined by two blinded observers.

RESULTS

The lag-phase duration after coffee (median 19.8 min, range 6-47 min) was not significantly different from that after water (median 19.3 min, range 11-37.5), nor was the gastric half-emptying time (median 75.7 min, range 56-157.6 vs. median 83.4 min, range 64. 6-148.4). Likewise, coffee had no significant effect on oro-caecal transit time (median 135 min, range 60-270 vs. median 140 min, range 55-270). No significant correlation between any of these parameters and mean daily coffee intake was found.

CONCLUSIONS

Coffee does not affect gastric emptying of a liquid meal or small bowel transit.

Sex differences in long-term stress-induced colonic, behavioural and hormonal disturbances

Functional bowel disorders are more prevalent in women than in men, but the reason for this is unclear. Stressful experiences can increase the risk for or precipitate intestinal dysfunction. Using a model for long-term stress-induced sensitisation in rats, it was investigated whether male and female rats differ in susceptibility for long-term colonic, behavioural and hormonal disturbances following brief but intense stress. Male and female Wistar rats were fitted with chronic electrodes on proximal colon and given either a 15-minute session of foot shocks or no shocks. Two weeks later, rats were exposed to two different novel stressful challenges in the home cage: an electrified prod (day 14) and an 85 dB noise stressor (day 15). Digitalised colonic myoelectric spike burst activity was quantified automatically. Behaviour during prod and noise exposure was scored blindly from videotape. Resting plasma hormone concentrations at the end of the study were determined by radio-immuno assay. Following prod stress on day 14, both male and female preshocked rats showed a greater increase in colonic spike burst frequency than controls, but similar behaviour, and the dynamics of colonic motility differed between sexes. Following noise stress on day 15, only a small change in burst frequency was seen in all rats, but preshocked rats showed less self-grooming behaviour and there was a tendency for preshocked females to show increased noise-induced immobility. Preshocked rats also had lower levels of plasma free thyroxine. While both male and female rats show long-term stress-induced colonic sensitisation and hormonal changes, females show a different activation pattern of colonic motility, and may be more vulnerable for altered behavioural reactivity, following stress.

The effect of a sports drink on gastroesophageal reflux during a run-bike-run test

The effects of different modes of prolonged exercise and different drinks on gastroesophageal reflux and reflux-related symptoms were examined. In a cross-over design seven male triathletes performed two tests at one week intervals (50 min periods of alternately running, cycling and running at 70-75% VO2max), with supplementation of either a conventional sports drink (7% carbohydrates) or tap water. Gastroesophageal reflux (percentage time and number of periods esophageal pH < 4) was measured with an ambulant pH system before, during and after exercise. Percentage reflux time (+/- SEM) during running, cycling, running and recovery was 24.0 +/- 4.6, 8.2 +/- 4.8, 17.6 +/- 8.4 and 11.8 +/- 4.0 with carbohydrates and 7.4 +/- 2.9, 0 +/- 0, 2.4 +/- 1.4 and 0.2 +/- 0.2 with water, respectively. Reflux lasted longer during exercise as compared to the rest situation (5.6 + 1.4%), especially with carbohydrates, and lasted longer with carbohydrates than with water (P < 0.05; Wilcoxon signed rank test). In general, reflux lasted longer during running than during cycling (P < 0.05). Data on the number of reflux periods are concordant to these results. Chest pain was reported by one subject during running with carbohydrates. Heartburn during running was reported by two subjects with water and by one with carbohydrates. In conclusion, physical exercise increases gastroesophageal reflux, dependent on the mode of exercise and beverage used.

Gastrointestinal mucosal integrity after prolonged exercise with fluid supplementation

PURPOSE

Studies on the effect of exercise on gastrointestinal (GI) mucosal integrity have been limited to occult-blood tests, which were often nonspecific for human blood. The aim of our study was to investigate more aspects of this integrity.

METHODS

We examined the effect of prolonged exercise and carbohydrate (CHO) supplementation on mucosal integrity in 22 male triathletes by measuring fecal lysozyme, alpha1-antitrypsin, and occult-blood loss, which was examined by two tests specific for human blood (Colon-Albumin and Monohaem test). Exercise consisted of two 150-min tests (alternately running, cycling, and running at 70-75% VO2max), either with a 7.0% CHO drink or water (W). Furthermore, GI symptoms during exercise were registered by questionnaire.

RESULTS

Three subjects showed human albumin only in the first stool after exercise: twice with W and once with CHO. However, human hemoglobin (Hb) could not be detected in these samples. Four other subjects showed an elevated lysozyme concentration after exercise with CHO but not with W. Elevated alpha1-antitrypsin values were found in three of seven specimens in which either positive albumin tests and/or an elevated lysozyme concentration were demonstrated. Twenty-one subjects (95%) reported one or more GI symptoms during exercise. Incidence rates of different GI symptoms varied from 5 to 68%. Most symptoms were more frequent and lasted longer during running than during cycling but did not differ significantly between supplements and were not related to any mucosal integrity parameter.

CONCLUSIONS

GI blood loss during exercise is of no clinical importance, at least in our study design with a group of well-trained male subjects who consumed a relatively high amount of fluid (up to 2.3 L). Nevertheless, an increased alpha1-antitrypsin and lysozyme concentration may indicate a transient local mucosal damage with an inflammatory response.

Ileoneorectal anastomosis: early clinical results of a restorative procedure for ulcerative colitis and familial adenomatous polyposis without formation of an ileoanal pouch

OBJECTIVE

To evaluate a new surgical procedure, ileoneorectal anastomosis (INRA), in patients with ulcerative colitis (UC) and familial adenomatous polyposis (FAP).

SUMMARY BACKGROUND DATA

Surgical treatment in UC and FAP aims to resect diseased colonic mucosa and restore oroanal continuity. The ileopouch anal anastomosis achieves this but has a 15% to 35% complication rate, a 10% failure rate, and an unpredictable functional outcome. An alternative surgical technique, INRA, has been developed in which the rectal mucosa is replaced by a vascularized ileal mucosa graft.

METHODS

Eleven patients underwent an INRA procedure with a temporary diverting ileostomy. Clinical history, repeat endoscopy, histologic examination, and rectal compliance measurements were carried out before and after surgery.

RESULTS

The INRA procedure was technically successful in all patients. Endoscopy showed ingrowth of ileal mucosa in the neorectum, with 100% coverage after 6 weeks. No patient had pelvic sepsis, neorectal-anal or -vaginal fistula, autonomic nerve damage, or fecal incontinence. Neorectal function improved with time. The median 24-hour defecation frequency decreased from 15 (range 9 to 25) to 7 (range 4 to 10) at 11 months follow-up, and the median maximum tolerated volume increased to 157 (range 130 to 225) ml. Anal manometry and electrosensitivity were not affected by the surgery. Histologic biopsy samples after 1 year showed a normal small intestinal mucous membrane, without inflammation or fibrosis.

CONCLUSION

The combination of a low complication rate and good neorectal function at 1 year is a substantial improvement that justifies extension of the clinical application in patients with UC and FAP.

Gastric compliance, sensation, and the relaxation response to a nitric oxide donor in health and reflux oesophagitis

BACKGROUND/AIMS

The gastric fundus affects afferent control of lower oesophageal sphincter function. Nitric oxide is an important relaxant of the fundus. We postulated that gastric distensibility, compliance and nitric oxide sensitivity may be altered in patients with gastro-oesophageal reflux disease (GERD).

METHODS

9 patients with erosive oesophagitis (6 males; median age 55 years) and 16 healthy controls (9 males; median age 36 years) were studied fasting with a gastric barostat. Minimal distending pressure (MDP) and gastric compliance (Deltav/Deltap) were determined by increasing intrabag pressure in 2-mm Hg increments. The pressures required to produce initial sensation and maximum tolerated sensation were recorded. With the intrabag pressure set at MDP +2 mm Hg, 500 microg sublingual glyceryl trinitrate was administered and the percentage change in intrabag volume from initial volume recorded.

RESULTS

The MDP was significantly greater in patients than controls (7.5 vs. 6.7 mm Hg median; p = 0.02). Gastric compliance was similar in both groups (57.8 vs. 67.2 ml/mm Hg; p = 0.4). There was no difference between groups in the pressure at first intragastric sensation (11.2 vs. 10.3 mm Hg above MDP; p = 0.5) or in the maximal tolerated pressure (15.8 vs. 14.3 mm Hg above MDP; p = 0.2). The proportional change in gastric volume from baseline in response to glyceryl trinitrate was smaller in patients than controls (66 (3-200) vs. 120 (26-1,053)%; p = 0.02).

CONCLUSIONS

Gastric MDP may be altered in GERD, but gastric compliance and sensitivity to distension are normal. Major gastric relaxation occurs in response to a nitric oxide donor, but this appears to be diminished in patients with GERD. Upper gut nitrinergic mechanisms may be altered in oesophageal reflux disease.

Evidence for 5-HT7 receptors mediating relaxation of human colonic circular smooth muscle

5-HT4 receptors mediate relaxation of human colon circular muscle. However, after 5-HT4 receptor blockade (SB 204070 10 nM), 5-HT still induced a relaxation (pEC50 6.3). 5-HT4 receptors were sufficiently blocked, as the curves to 5-HT obtained in the presence of 10 and 100 nM SB 204070 were indistinguishable. This 5-HT-induced relaxation was tetrodotoxin-insensitive, indicative of a smooth muscle relaxant 5-HT receptor. This, and the rank order of potency (5-CT=5-MeOT=5-HT) suggested involvement of 5-HT1 or 5-HT7 receptors. Mesulergine, a 5-HT7 receptor antagonist at nanomolar concentrations, and a 5-HT1 receptor antagonist at micromolar concentrations, competitively antagonized the 5-HT-induced relaxation (pKB 8.3) and antagonized the relaxation to 5-CT. Methysergide antagonized the 5-HT-induced relaxation (pA2 7.6). It is concluded that the profile of the smooth muscle inhibitory 5-HT receptor resembles that of the 5-HT7 receptor. These data provide the first evidence for functional human 5-HT7 receptors.

The effect of omeprazole on gastro-oesophageal reflux and symptoms during strenuous exercise

BACKGROUND

Strenuous exercise exacerbates gastro-oesophageal reflux and symptoms and this may be diminished by antisecretory medication with omeprazole.

METHODS

Fourteen well-trained athletes (13 men, one woman), who indicated suffering from either heartburn, regurgitation or chest pain during competition running, performed two experimental trials at 2-week intervals using a randomized, double-blind, placebo-controlled crossover design. During the 6 days preceding the trial and on the trial day itself either 20 mg of omeprazole or a placebo was administered. Two hours after a low-fat breakfast and 1 h after the last study dose, the trial started with five successive 50-min periods: rest, three running periods on a treadmill, and recovery. Reflux (percentage time and number of periods oesophageal pH <4) was measured with an ambulant pH system during these periods.

RESULTS

Compared to rest, reflux lasted significantly longer and occurred more frequently during the first running period, irrespective of the intervention, whereas during the second running period this effect was only observed with the placebo. Reflux occurred for longer and more frequently with the placebo than with omeprazole, but this was significant during the first two running periods only. Seven subjects reported heartburn, regurgitation and/or chest pain during exercise, irrespective of the intervention. Only a minority of the symptom periods was actually associated with acid reflux and in all cases this concerned periods with heartburn.

CONCLUSIONS

Running-induced acid reflux, but not symptoms, were decreased by omeprazole, probably because most symptoms were not related to acid reflux.

Pharmacological characterization of 5-HT4 receptors mediating relaxation of canine isolated rectum circular smooth muscle

This study aimed to characterize for the first time in vitro 5-HT4 receptors in the canine gastrointestinal tract. For this purpose, we used circular muscle strips of the canine isolated rectum. In the presence of methysergide (60 microM), 5-HT induced relaxation of methacholine (1 microM)-precontracted muscle strips, yielding a monophasic sigmoidal concentration-relaxation curve (pEC50 7.2+/-0.07). Tetrodotoxin (0.3 microM) did not affect the curve to 5-HT, suggesting the inhibitory 5-HT receptor is located on the smooth muscle. Granisetron (0.3 microM) did also not affect the curve to 5-HT, which excludes the 5-HT3 receptor mediating the relaxation to 5-HT. The presence of methysergide rules out the involvement of 5-HT1, 5-HT2 or 5-HT7 receptors. 5-HT, the selective 5-HT4 receptor agonists R076186, prucalopride (R093877) and SDZ HTF-919 and the 5-HT4 receptor agonists cisapride and 5-MeOT relaxed the muscle strips with a rank order of potency R076186 = 5-HT > cisapride > prucalopride > or = SDZ HTF-919 > 5-MeOT. The selective 5-HT4 receptor antagonists GR 125487, RS 39604 and GR 113808 competitively antagonized the relaxations to 5-HT, yielding pK(B) estimates of 9.7, 7.9 and 9.1, respectively. The selective 5-HT4 receptor antagonist SB 204070 shifted the curve to 5-HT rightward and depressed the maximal response (apparent pA2 10.6). GR 113808 (10 nM) produced a parallel rightward shift of the curve to the selective 5-HT4 receptor agonists R076186 (pA2 8.8). It is concluded that 5-HT induces relaxation of the canine rectum circular muscle through stimulation of a single population of smooth muscle 5-HT4 receptors. For the first time, a nonhuman species was shown to exhibit relaxant 5-HT4 receptors in the large intestine.

Gastrointestinal symptoms in long-distance runners, cyclists, and triathletes: prevalence, medication, and etiology

OBJECTIVE

The aim of this study was to determine the prevalence of exercise-related gastrointestinal (GI) symptoms and the use of medication for these symptoms among long-distance runners, cyclists, and triathletes, and to determine the relationship of different variables to GI symptoms.

METHODS

A mail questionnaire covering the preceding 12 months was sent to 606 well-trained endurance type athletes: 199 runners (114 men and 85 women), 197 cyclists (98 men and 99 women), and 210 triathletes (110 men and 100 women) and sent back by 93%, 88%, and 71% of these groups, respectively. Symptoms were evaluated with respect to the upper (nausea, vomiting, belching, heartburn, chest pain) or lower part of the GI tract (bloating, GI cramps, side ache, urge to defecate, defecation, diarrhea). For statistical analysis, Mann-Whitney U test, Fisher exact test, or Student t test were used.

RESULTS

Runners experienced more lower (prevalence 71%) than upper (36%) GI symptoms during exercise. Cyclists experienced both upper (67%) and lower (64%) symptoms. Triathletes experienced during cycling both upper (52%) and lower (45%) symptoms, and during running more lower (79%) than upper (54%) symptoms. Bloating, diarrhea, and flatulence occurred more at rest than during exercise among all subjects. In general, exercise-related GI symptoms were significantly related to the occurrence of GI symptoms during nonexercise periods, age, gender, diet, and years of training. The prevalence of medication for exercise-related GI symptoms was 5%, 6%, and 3% for runners, cyclists, and triathletes, respectively.

CONCLUSIONS

Long-distance running is mainly associated with lower GI symptoms, whereas cycling is associated with both upper and lower symptoms. Triathletes confirm this pattern during cycling and running. The prevalence of medication for exercise-related GI symptoms is lower in the Netherlands in comparison with other countries, in which a prevalence of 10-18% was reported. More research on the possible predisposition of athletes for GI symptoms during exercise is needed.

The effect of cisapride on duodenal acid exposure in the proximal duodenum in healthy subjects

AIM

To investigate the effect of the prokinetic drug, cisapride, on fasting and postprandial acid exposure in the proximal duodenum.

METHODS

Using a double-blind, placebo-controlled crossover study design, 12 healthy male volunteers were studied. After 1 week of dosing (cisapride 20 mg b.d. orally or placebo), fasting and postprandial antroduodenal pH-and pressure-recordings were made. Using a small-caliber (4 mm) catheter, containing one antral and two duodenal pH electrodes, and two antral and three duodenal pressure recording sites. Transmucosal potential difference was measured to ensure proper catheter position. Infusions of 0.1 N HCl were given in the duodenal bulb.

RESULTS

Endogenous acidification of the duodenal bulb occurred more frequently during phase II and postprandially, compared to phase I (P<0.001). During phase I, alkalinization of the antrum was observed. Cisapride significantly increased the postprandial number of duodenal acidic periods (P<0.02), but shortened their duration (P<0.04). The duodenal motor response elicited by exogenous acid was lower during phase I (P<0.05).

CONCLUSIONS

Antral and proximal duodenal acidity vary with the phases of the interdigestive motor complex. Cisapride shortens the individual periods of duodenal acidification.

Different effects of an oral anticholinergic drug on gastroesophageal reflux in upright and supine position in normal, ambulant subjects: a pilot study

OBJECTIVE

There is controversy in the literature on the effects of anticholinergic drugs on gastroesophageal reflux. Our aim was to study more extensively the effects of an oral anticholinergic drug on esophageal motility and gastroesophageal reflux in normal ambulant subjects under different circumstances: upright, supine, fed, and fasted state.

METHODS

Fifteen healthy subjects (seven men, eight women), mean age 34 yr (range, 22-61 yr) underwent randomized placebo-controlled 16-h evening and overnight ambulatory esophageal motility/pH study. After a 3-day loading dose of either oral dicyclomine (Dic) 20 mg four times daily or placebo (Pla), an ambulatory esophageal motility/pH study was performed while taking medication or placebo. Each study was analyzed for meal, first and second h postprandial, upright and supine periods, and first 2 h supine after bedtime snack.

RESULTS

The mean number of reflux episodes decreased with dicyclomine during the first h postprandial (Dic, 1.9 vs Pla, 2.5; p < 0.05). During the first 2 h supine, mean number of reflux episodes increased with dicyclomine (Dic, 1.4 vs Pla, 0.8; p < 0.09), as did mean percent time pH < 4 (Dic, 2.6 vs Pla, 0.5; p < 0.04), with an increase in clearance time (Dic, 0.9 vs Pla, 0.3; p < 0.05; in min). Mean peristaltic amplitude decreased with dicyclomine during the 2nd h postprandial (Dic, 48.8 vs Pla, 56.3; p < 0.04).

CONCLUSIONS

Oral dicyclomine caused a decrease in early postprandial upright reflux episodes, but also significantly increased the percent time pH < 4 during the first two h supine. Therefore, its effects are dependent on body position and fasted or fed state. Our results justify additional studies with oral anticholinergic agents in patients with gastroesophageal reflux disease.

Long-term sensitization of Fos-responsivity in the rat central nervous system after a single stressful experience

There is considerable evidence for a role of stressful experiences in psychosomatic disorders in humans, but the mechanisms leading to altered responsivity and the relative contributions of central and peripheral neuronal changes, however, are still under debate. To investigate the contribution of specific brain areas to sensitized responsivity, rats were exposed to a single brief session of inescapable footshocks (preshocked) or no shocks (control) in a gridcage. Two weeks later, an electrified prod was inserted in the home cage for 15 min and the behaviour recorded. One hour later rats were perfused and brain sections were stained for Fos protein immunoreactivity. The number of Fos positive neurons was quantified in 27 brain areas. No significant difference in behaviour was found between the groups during the shock prod challenge. A significantly higher number of Fos positive neurons was found in preshocked rats compared to controls in the following brain areas: agranular insular cortex, frontal cortex, nucleus accumbens, bed nucleus of the stria terminalis, basolateral amygdala, CA1 area of the hippocampus, paraventricular hypothalamic nucleus, dorsolateral central grey, locus coeruleus, nucleus of the solitary tract and lateral paragigantocellular nucleus. We conclude that altered reactivity to stressful challenges in brain areas involved in neuroendocrine and autonomic control may play a role in long-term sensitization of neuroendocrine and autonomic responses in preshocked rats under conditions where behavioural sensitization is not expressed.

The effects of ABT-229 and octreotide on interdigestive small bowel motility, bacterial overgrowth and bacterial translocation in rats

BACKGROUND

Interdigestive small bowel motility has a regulatory function on the microflora of the upper small bowel. Here we investigate the effects of ABT-229 and octreotide on morphine-induced dysmotility, the accompanying bacterial overgrowth and bacterial translocation.

METHODS

Rats were fitted with jejunal myoelectrodes and a subcutaneous cannula for continuous infusion of saline or morphine. Fasting motility was measured for 6 h on four occasions: one control measurement (day 0) and three measurements on consecutive days (days 1-3) while receiving saline alone (group A), morphine alone (group B), saline + ABT-229 (group C), morphine + ABT-229 (group D), saline + octreotide (group E) or morphine + octreotide (group F). Samples from the mesenteric lymph node complex (MLN), liver, spleen, duodenum and ileum were taken for quantitative microbial culturing on day 4.

RESULTS

Neither ABT-229 nor octreotide increased the number of propagated activity fronts during saline infusion. During morphine-induced dysmotility, ABT-229 induced more propagated activity fronts in group D (13.4, 9.8 and 8.8 per 6 h) than in group B (7.0, 4.5, 3.8 per 6 h) on days 1, 2 and 3 (P < 0.05 for all days) Octreotide did not induce more propagated activity fronts. Disruption of small bowel motility by morphine led to bacterial overgrowth in the duodenum. ABT-229 and octreotide did not reduce the bacterial growth levels. The total incidence of bacterial translocation was significantly higher in the morphine-treated animals than in the saline-treated animals. Neither ABT-229 nor octreotide reduced the bacterial translocation incidence. The number of propagated activity fronts on day 3 and duodenal bacterial growth correlated significantly in groups A, E and F.

CONCLUSIONS

ABT-229, but not octreotide, reduced morphine induced dysmotility. Small bowel bacterial overgrowth and bacterial translocation were not prevented. Fasting small bowel motility has a regulatory function on the intestinal microflora of the upper small bowel.

Psychoneurogastroenterology: interrelations in stress-induced colonic motility and behavior

Individual differences in behavioral and physiological response patterns to stress may contribute to vulnerability for stress-related illnesses such as functional gastrointestinal disorders. Animal models could give clues about specific individual determinants of intestinal reactivity to stress and stress-induced sensitization. Rats fitted with permanent electrodes on the proximal colon were exposed to a single session of foot shocks (10 x 6 s in 15 min, preshocked) or no shocks (control). Two weeks later, the preshocked group showed a significantly greater colonic spike burst response to a novel shock-prod stressor in the home cage than controls. The increase in burst frequency was positively correlated with the duration of active burying of the threatening prod in both experimental groups, but not with other behavioral components. Basal colonic burst frequency at rest was negatively correlated with the increase in burst frequency due to shock-prod stress in both groups, but the degree of sensitization in preshocked rats vs. controls was of similar magnitude in rats with low and high basal colonic burst frequency. The results indicate that colonic responsivity to stress is related to both basal motility status and individual coping strategies.

Stomach distension increases efferent muscle sympathetic nerve activity and blood pressure in healthy humans

Although the enteric nervous system is usually described as a separate and independent entity, animal studies show that gastric distension causes a reflex increase in arterial pressure and a sympathetically mediated increase in heart rate and peripheral vascular resistance. To assess the influence of gastric distension on sympathetic outflow and blood pressure, we recorded muscle sympathetic nerve activity (MSNA) from the peroneal nerve by microneurography in eight healthy volunteers. The stomach was distended by means of a barostat, using a single staircase protocol by which pressure was increased by 2 mmHg every 3 min. Gastric sensory function was assessed at each distension step by using a visual analog scale (VAS) for sensations of fullness, nausea and pain. For comparison, we also performed a cold pressor test. The MSNA increased on barostat-induced gastric distension with an almost concomitant elevation of blood pressure. The increase in both was proportional to the intragastric pressure and both decreased towards initial values after the end of distension. Heart rate increased inconsistently and only at higher distension pressures that were associated with high VAS scores. The opposite was found for the cold pressor test. The results of this study confirm the existence of a functional relationship between gastrointestinal distension and cardiovascular function. Decrease in this gastrovascular response may play a role in postprandial hypotension in the elderly, since the MSNA responses to simulated microgravity decrease with age.

Migrating motor complex cycle duration is determined by gastric or duodenal origin of phase III

The migrating motor complex (MMC) shows large variations within an individual and between individuals. This study aimed to investigate, with respect to this variability, the importance of gastric or duodenal origin of phase III activity. Interdigestive 6- to 10-h stationary antroduodenal motility recordings of 19 healthy male subjects were analyzed for MMC cycle durations and duration of phases I, II, and III, all with respect to the place of origin of each phase III. Data are given for the duodenal recording site as means +/- SE. Mean MMC cycle duration was 117.3 +/- 13.9 min, regardless of the place of origin of phase III. Seventy-two phase III cycles were observed in total, 35 and 37 starting in the "antrum" and duodenum, respectively. After a phase III of "antral" origin, MMC cycle duration was 156.1 +/- 11.0 min, significantly longer than MMC cycle duration following a phase III of duodenal origin, 80.5 +/- 10.7 min (P < 0.001). Phase III duration was longer when of "antral" origin than when starting in the duodenum (7.6 +/- 0.4 and 5.3 +/- 0.4 min, respectively; P < 0.001). MMC cycle duration and duration of phases I, II, and III depend on the place of origin of phase III ("antral" or duodenal) and on the origin of the preceding phase III. This factor explains part of the MMC variability observed within individuals. Mean MMC cycle duration in healthy subjects or patients should therefore also include information on the origin of phase III.

Gastrointestinal motility and gastric tube feeding in mechanically ventilated patients

OBJECTIVE

To determine the fasted and fed gastrointestinal motility characteristics that are possibly responsible for gastric retention in mechanically ventilated patients.

DESIGN

Prospective, case series.

SETTING

Surgical intensive care unit of a university hospital.

PATIENTS

Seven patients who required mechanical ventilation for thoracic or combined thoracic-neurologic injuries and nine healthy volunteers.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Antroduodenal manometry was performed during fasting and gastric feeding with a polymeric diet in patients during mechanical ventilation, weaning, and after detubation. Gastric retention volumes were determined during gastric tube feeding. Motility data were compared with recordings from nine healthy volunteers. During the fasting state, under sedation and morphine, the migrating motor complex in patients was significantly (p < .001) shortened: median 32.0 vs. 101.0 mins in healthy volunteers. During gastric tube feeding, the motility pattern did not convert to a normal postprandial pattern until morphine was discontinued. An interdigestive or mixed interdigestive-postprandial pattern was seen during gastric tube feeding in most patients during morphine administration. Most (94%) of the activity fronts during gastric feeding started in the duodenum. Gastric retention percentages during gastric tube feeding were negatively correlated (r2=.44; p < .01) with antral motor activity.

CONCLUSIONS

These data suggest that morphine administration affects antroduodenal motility in mechanically ventilated patients. The gastrointestinal motor pattern involved in impaired gastric emptying in morphine-treated patients is characterized by antral hypomotility and persisting duodenal activity fronts during continuous intragastric feeding. The observed motility patterns suggest that early administration of enteral feeding might be more effective into the duodenum or jejunum than into the stomach of mechanically ventilated patients.

Circulating gastrointestinal hormone abnormalities in patients with severe idiopathic constipation

OBJECTIVE

This study aimed to determine if there is an abnormality of circulating gastrointestinal hormones in patients with severe idiopathic constipation.

METHODS

Twelve patients, all female (median age 34 yr) and 12 healthy controls (eight female, median age 32 yr) were studied. A radioisotope-labeled solid/liquid meal was ingested, and the serum hormone response, as well as the relationship between serum hormones and rates of gastric emptying and small intestinal transit, were studied for 180 min postprandially.

RESULTS

Somatostatin levels were higher in patients with constipation (basal level, controls vs patients, 31 vs 57 pmol/L, p < 0.05, median values; peak level, 48 vs 60, p < 0.05). Patients showed a significantly lower somatostatin integrated incremental meal response (2182 vs 104, p < 0.05). No correlation was found between the somatostatin levels and rates of upper gastrointestinal transit in patients. Pancreatic glucagon was significantly decreased (p=0.04). Enteroglucagon levels were significantly lower (p > 0.05) in patients between 30 and 60 min after the meal. The peak found after the meal in normal subjects was absent. Basal levels of pancreatic glucagon correlated with small bowel transit by two different measures: head of meal (r=0.69, p=0.03) and cecal filling at the time of 50% gastric emptying (r=0.84, p=0.002). No significant differences between the two groups could be found for basal and peak levels at different times and integrated incremental response to the meal for insulin, gastric inhibitory polypeptide (GIP), glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), gastrin, pancreatic polypeptide (PP), motilin, neurotensin, and peptide tyrosine tyrosine (PYY).

CONCLUSION

Patients with severe idiopathic constipation have specific abnormalities of circulating gut hormones that most likely play a role in gastrointestinal motility and that may be of pathophysiological significance.

The role of interdigestive small bowel motility in the regulation of gut microflora, bacterial overgrowth, and bacterial translocation in rats

OBJECTIVE

To clarify the role of the migrating motor complex (MMC) in the regulation of small intestinal microflora and bacterial translocation.

SUMMARY BACKGROUND DATA

The intestinal microflora may serve as a source of infectious microorganisms. Failure of regulatory mechanisms of the intestinal flora could therefore play an important role in the pathogenesis of gut-derived infections.

METHODS

Rats were fitted with small intestinal myoelectrodes. MMCs were measured on a control day and 3 consecutive days during continuous administration of morphine or placebo. Mesenteric lymph nodes, liver, spleen, peripheral blood, duodenum, and ileum samples were cultured quantitatively.

RESULTS

The mean MMC cycle length in placebo-treated animals was 15.1+/-0.5 minutes. MMCs were completely disrupted after morphine treatment. Total bacterial growth in the duodenum was 7.27+/-0.34 10log colony-forming units (CFU)/g with placebo and 8.28+/-0.27 CFU/g with morphine. In placebo-treated animals, the mean MMC cycle length the day before culturing correlated with total bacterial growth in the duodenum. Translocation incidences to the mesenteric lymph nodes, liver, spleen, and blood were 0/8, 1/8, 0/8, and 0/8 with placebo and 7/8, 6/8, 5/8, and 0/8 with morphine. The overall translocation incidence was 1/8 in placebo-treated animals and 8/8 in morphine-treated animals.

CONCLUSIONS

The MMC is an important mechanism controlling bacterial growth in the upper small bowel. Its disruption with morphine promotes duodenal bacterial overgrowth and bacterial translocation.

Effects of long-term oral L-arginine on esophageal motility and gallbladder dynamics in healthy humans

Inhibitory nitrergic neurons are known to play a role in the regulation of motility patterns of the distal esophagus, the lower esophageal sphincter (LES), and the gallbladder. Our study aim was to investigate the effects of "long-term" (i.e., prolonged) oral intake of L-arginine (L-Arg), the endogenous source for nitric oxide (NO) synthesis, on postprandial LES pressure (LESP), esophageal motility, gastroesophageal reflux, and gallbladder motility. L-Arg (30 g/day) or glycine (placebo; 13 g/day; isosmolar) was given orally to 10 healthy male volunteers for 8 days, according to a randomized, crossover design. Twenty-four-hour urinary nitrite/nitrate excretion was measured to indicate NO synthesis. Basal early postprandial LESP was lower after L-Arg ingestion (2.2 kPa) than after glycine ingestion (2.7 kPa) (P < 0.05). L-Arg abolished the physiological late postprandial rise in LESP. Transient LES relaxations were longer lasting after L-Arg ingestion (P < 0.02). Esophageal motility and reflux were not affected (not significant). Fasting and residual gallbladder volumes were greater after L-Arg ingestion (P < 0.05). Urinary nitrite/nitrate excretion was higher after L-Arg intake (P < 0.05). In conclusion, long-term oral L-Arg suppresses late postprandial LESP increase, prolongs transient LES relaxations, and increases fasting and residual gallbladder volumes. These effects may be mediated by increased NO synthesis.

Motilin induces gall bladder emptying and antral contractions in the fasted state in humans

BACKGROUND

Animal studies have shown that motilin affects gall bladder motility. In humans, no effect has been shown, but erythromycin, a motilin receptor agonist, induces gall bladder emptying.

AIMS

To explore the effect of increasing doses of exogenous motilin on gall bladder volume and antral contractility in the fasted state in humans.

METHODS

After an overnight fast, eight healthy men received increasing intravenous doses of Leu13-motilin (KW-5139) or 0.9% NaCl in a double blind, randomised fashion. Gall bladder volume and antral contraction frequency were determined by ultrasonography.

RESULTS

Infusion of motilin increased plasma motilin levels. Motilin induced a reduction in gall bladder volume of 8.0 (5.0)%, 17.1 (5.0)%, 18.5 (4.7)%, and 16.1 (4.9)% of baseline volume at the end of infusion of 2, 4, 8, and 16 pmol/kg/min respectively, compared with mean stable gall bladder volumes during placebo infusion (p < 0.05). Antral contraction frequency increased during motilin infusion, but not during placebo infusion (p < 0.05).

CONCLUSIONS

Exogenous motilin reducted fasting gall bladder volume and increased antral contractions. After reaching maximal reduction, the gall bladder volume did not decrease further during continuous motilin infusion at higher doses and stayed at the same reduced volume. The degree of gall bladder volume reduction during motilin infusion mimicked gall bladder emptying preceding antral phase III activity of the migrating motor complex in humans. This study indicates that motilin may play a physiological role in the regulation of gall bladder emptying in the fasted state.

Responses to gastric distension in functional dyspepsia

BACKGROUND

Studies have shown that an altered visceral perception threshold plays a role in the pathogenesis of upper gastrointestinal tract symptoms in dyspeptic patients. However, it is not clear whether the compliance and adaptive relaxation of the proximal stomach contribute to the symptoms.

AIMS

To investigate whether abnormal relaxation or adaptation of the proximal stomach during the interdigestive state and the postprandial phase could explain the symptoms of functional dyspepsia.

SUBJECTS

Twelve volunteers and 12 patients with dysmotility-like functional dyspepsia were included in the study.

METHODS

An electronic barostat was used to investigate adaptation to distension of the proximal stomach and accommodation in response to a liquid meal. Dyspeptic symptoms during distension and accommodation were assessed.

RESULTS

When the subjects were in the fasting state, the pressure-volume curve showed slightly higher compliance in the dyspeptic patients (p < 0.05). Patients not only had a higher score for nausea, bloating, and pain but also the increase in nausea and pain scores with intragastric pressure was higher than in volunteers (p < 0.05). The increase in intragastric bag volume in response to a meal was significantly lower in patients (p < 0.05). Both bloating and pain significantly increased in the patients (p < 0.05), but not in the healthy volunteers.

CONCLUSIONS

Patients with functional dyspepsia show slightly higher compliance to mechanical distension. Their visceral perception of mechanical stress is enhanced. In contrast with the balloon distension, relaxation after a meal was less. Therefore the postprandial symptoms cannot be explained fully by greater global tension in the stomach wall, as assessed by the barostat technique. Visceral hypersensitivity plays a major role in the pathogenesis of the symptoms.

Proximal gastric motor activity in response to a liquid meal in type I diabetes mellitus with autonomic neuropathy

Disordered gastric emptying occurs in 30-50% of patients with diabetes mellitus. Although the rate of gastric emptying is dependent on the integration of motor activity in different regions of the stomach, there is limited information about the function of the proximal stomach in diabetes mellitus. In the present study the response of the proximal stomach to a liquid meal was examined in eight diabetic patients with autonomic neuropathy and gastrointestinal symptoms and in 10 healthy volunteers, using an intragastric bag connected to an electronic barostat. Postprandial relaxation of the proximal stomach was measured as an increase of intragastric bag volume at a constant pressure level of 1 mm Hg above the intraabdominal pressure. During the experiment the blood glucose levels were maintained within the euglycemic range. Before ingestion of the meal the intragastric bag volume was larger in the diabetic patients than in the healthy volunteers, 234.4 +/- 29.1 ml vs 155.3 +/- 15.3 ml (P = 0.06). The maximum volume was not different in diabetics compared to the healthy controls (386.3 +/- 45.2 ml versus 399.0 +/- 35.2 ml). However, the maximum volume increase was significantly less in diabetics (143.7 +/- 38.6 ml) compared to the controls (231.4 +/- 30.5 ml, P < 0.04). Bloating was inversely correlated with the volume changes, which suggests that impaired relaxation of the proximal stomach may play a role in the genesis of this sensation. In conclusion, this study shows a lower fasting fundal tone and a decrease in volume change of the gastric fundus after a nutrient drink in patients with autonomic neuropathy due to type I diabetes mellitus. These abnormalities may play a role in the abnormal distribution of food, disordered liquid gastric emptying, and in the genesis of the sensation of bloating observed in these patients.

Function of the proximal stomach after Nissen fundoplication

BACKGROUND

After Nissen fundoplication patients frequently report upper abdominal (dyspeptic) symptoms. Theoretically, these symptoms may be the result of changes in function of the proximal stomach as induced by fundoplication.

METHODS

In this case-control study the response of the proximal stomach to both distension by an air-filled bag and a liquid meal were evaluated with the use of a barostat. In 12 patients after fundoplication and 12 healthy volunteers (age- and sex-matched) perception of symptoms was evaluated during both bag distension and liquid meal stimulus.

RESULTS

The minimal distending pressure required to overcome the intra-abdominal pressure was significantly different between patients and controls (mean(s.e.m.) 9.34(0.26) versus 6.73(0.43) mmHg; P < 0.001). There was no difference between groups in either the fasted state, volume-pressure curve (compliance) or total symptom score. After ingestion of the liquid meal the adaptive relaxation in the fundoplication group was significantly less than that in controls (mean(s.e.m.) 150(29.2) versus 244(34.8) ml; P = 0.04).

CONCLUSION

This study showed that after Nissen fundoplication compliance of the proximal stomach is no different from that in healthy volunteers. Postprandial relaxation of the proximal stomach is decreased and this abnormality may be involved in the pathogenesis of reported dyspeptic symptoms.