Irritable bowel syndrome: relationship of disorders in the transit of a single solid meal to symptom patterns

Role of anger in antral motor activity in irritable bowel syndrome

There is considerable evidence indicating that patients with irritable bowel syndrome respond to emotional and environmental stimulation with increased colon motor activity. It has been suggested also that increased colon motor activity is not confined to the colon and may be representative of a broader disorder affecting the rest of the gastrointestinal tract in this population. The results of our current study suggest that anger may have a significant, although differential effect on antral motor activity in IBS patients compared to normal controls. We found that while antral motor activity did not differ significantly in our groups during rest, anger decreased antral motor activity in IBS patients and increased antral motor activity in normal controls. The difference was not attributable to a difference in anger levels since the groups did not differ in their response to the standardized anger stressor. Rather, the difference in the antral motor response appears to be qualitative and a possible marker for irritable bowel syndrome. Our data further suggest that increased colon motor activity in IBS patients during emotional stress is not a result of a rise in motor activity throughout the gastrointestinal tract, but a phenomenon that may be unique to the colon in this patient population.

Patient subgroups in irritable bowel syndrome that can be defined by symptom evaluation and physical examination

Subgroups of patients with irritable bowel syndrome (IBS) are likely to respond differently to existing and evolving therapies. The following criteria for subgrouping may be considered: (1) Patients with different predominant bowel habits respond differently to treatment (antidepressants, 5HT3-antagonists, psychotherapy). (2) Postprandial exacerbation of pain or other gastrointestinal symptoms is seen in approximately half of patients with IBS and may identify patients who are more responsive to some classes of drugs (e.g., those targeted at motility). (3) Women appear to respond differently from men to 5HT3-antagonists, and there may be gender differences in gastrointestinal physiology. (4) There is more overlap in the diagnosis of functional dyspepsia and IBS than would be predicted by chance, and both are associated with hyperalgesia to intraluminal distention.

Relationship between terminal ileal pressure waves and propagating proximal colonic pressure waves

The relationship between propagating distal ileal and proximal colonic motor patterns has not been systematically examined in humans. Our aim was to define the relationships, if any, between prolonged propagating contractions or discrete clustered contractions and cecal propagating sequences using multiple manometric recording sites spanning the distal ileum and unprepared colon. In 14 healthy volunteers, a 17-lumen-perfused silicon catheter was positioned pernasally such that at least three recording sites lay in the ileum and the remainder in the colon. Intersidehole distance was 7.5 cm. In 271 h of recording, 30% of the terminal ileal propagating events was temporally associated with cecal propagating sequences. Significantly more prolonged propagating contractions (11 of 24, 46%; P = 0.02) were associated with cecal propagating sequences than were associated with ileal discrete clustered contractions (4 of 26, 15%). This trend was more pronounced at night. Of 159 cecal propagating sequences, 15 (9%) were preceded by an ileal propagating event. The remaining 91% was preceded by increased nonpropagating activity commencing 2 min before the cecal propagating sequence (P = 0.0002). We conclude that distal ileal propagating motor patterns are one stimulus for cecal propagating sequences, with the association being stronger for prolonged propagating contractions than for discrete clustered contractions.

Symptom differences in moderate to severe IBS patients based on predominant bowel habit

OBJECTIVE

We sought to determine if irritable bowel syndrome (IBS) patients with different bowel habit predominance differ in self-reported viscerosensory symptoms related to the upper and lower gastrointestinal (GI) tract, somatosensory symptoms, and constitutional functions.

METHODS

Six hundred and twenty-five Rome criteria-positive IBS patients completed a bowel symptom questionnaire (BSQ), psychological symptom checklist (SCL-90), and health status (SF-36). Bowel habit predominance for IBS patients was determined using the Rome criteria for functional constipation (IBS-C; n = 140) and functional diarrhea (IBS-D; n = 216). The BSQ included questions about viscerosensory symptoms of the upper (chest pressure, bloating, fullness, early satiety, nausea) and lower GI tract (bloating, pain, incomplete evacuation), somatosensory symptoms related to the musculoskeletal system (pain in neck/shoulders, lower back/hip, muscles/joints), and constitutional functions (sleep, appetite, libido). Analysis was further conducted between the IBS-C and IBS-D patients, controlling for gender and quality of sleep, and using the Bonferroni correction to control for multiple comparisons.

RESULTS

Female gender was more prevalent among IBS-C than IBS-D (77% vs 56.1%, p < 0.01), whereas age did not differ (40.2 +/- 1.2 yr vs 39.5 +/- 1.0 yr). Symptoms referred to the upper GI were more prevalent in IBS-C than IBS-D: early satiety (56.7% vs 33.9%, p < 0.004), fullness (63.2% vs 38.5%, p < 0.05), and a trend for upper bloating (80.3 vs 62.6%). IBS-C patients reported higher severity ratings for lower GI bloating (p < 0.001). IBS-C more commonly reported musculoskeletal symptoms (92.2% vs 75.4%, p < 0.001), as well as impairment in sleep (31.3 vs 17.5%, p < 0.009), appetite (35.0% vs 18.4%, p < 0.015) and sexual function (45.2% vs 33.1%, p < 0.0021). There were no differences in SCL-90 and SF-36 scores.

CONCLUSIONS

Compared with the IBS-D group, the IBS-C patients show greater prevalence of a wide range of symptoms referred to the upper and lower abdomen, musculoskeletal, and constitutional functions. These findings may be related to differences in autonomic or perceptual responses to visceral and somatic stimuli, and are likely to have implications for treatment responses in the two subgroups.

The pharmacokinetics of extended-release formulations of calcium antagonists and of amlodipine in subjects with different gastrointestinal transit times

The influence of gastrointestinal (GI) transit times on the pharmacokinetics (PK) of three calcium channel blockers (CCBs), recommended for once-daily dosing, was investigated. In a three-way crossover design, the single-dose PK of a controlled-delivery formulation of 240 mg diltiazem (DIL), an extended-release formulation of 10 mg felodipine (FEL), and 5 mg amlodipine (AML) were compared in two groups of healthy subjects, with either slow (> 35 h) or rapid (< 15 h) GI transit, as assessed by the metal detector method (EAS II). GI transit significantly affected the PK of DIL. Mean PK parameters in the rapid versus slow transit group were the following: trough levels (C24 h): 22.8 +/- 8.3 versus 49.5 +/- 35.7 ng/ml, p < 0.05; AUC 1134.4 +/- 512.7 versus 1704.7 +/- 1185.6 hng/ml, p < 0.05 (one-sided). Neither AUC nor trough levels of FEL and AML were significantly influenced by transit times, nor was Cmax after any of the three treatments. Variations in PK parameters, as indicated by coefficients of variation, were about twofold higher for both DIL and FEL, compared to AML. Variations in mean residence times were significantly lower for AML compared to DIL and FEL (7% vs. 30% and 17%, p < 0.001 and p < 0.002, respectively). Peak-to-trough ratios (Cmax/C24 h mean) were 1.8 +/- 0.9 for DIL, 7.6 +/- 3.5 for FEL, and 1.7 +/- 0.2 for AML. In conclusion, the predictability of pharmacokinetic behavior both in conditions of rapid or slow GI transit is optimized in drugs with intrinsically slow elimination such as amlodipine. The pharmacokinetics of the CCBs with formulation-based once-a-day characteristics are sensitive to GI transit if these processes are rapid enough to interfere with the formulation-specific release profile.

Inhibition of gastric secretion relieves diarrhea and postprandial urgency associated with irritable bowel syndrome or functional diarrhea

Five patients with gastroesophageal reflux disease (GERD), who also had chronic functional diarrhea and postprandial urgency, unexpectedly noted rapid relief of their diarrhea and urgency when they took lansoprazole for their heartburn. To determine if this surprising result was not fortuitous, all 20 patients seen during the next six months for chronic diarrhea and postprandial urgency due to irritable bowel syndrome (IBS) or functional diarrhea were treated with inhibitors of gastric secretion: 14 with proton-pump inhibitors and 6 with H2 blockers. All patients had rapid, marked improvement. Usually within three days, their symptoms abated and they usually had one to three formed stools per day. Relief continued during the one to six months they were followed on therapy. Five patients stopped therapy, had recurrent diarrhea, and rapid relief upon resuming therapy. Thus, inhibition of gastric secretion effectively controls the diarrhea and postprandial urgency associated with IBS or functional diarrhea, probably by diminishing the gastrocolic or gastroenteric reflex.

The patterns of small bowel motility: physiology and implications in organic disease and functional disorders

The physiology and pathophysiology of small bowel motility are reviewed with particular focus on the motility patterns and periods that are detected by intraluminal manometry. Motility patterns are groups of phasic pressure waves resulting from contractions of the circular muscle layer of the small bowel that are organized by the enteric nervous system. Phase III of the migrating motor complex, the hallmark of the fasting motility period, thus reflects enteric neuromuscular function. Response to meal challenge also involves the CNS, reflexes beyond the gut and endocrine responses. Although specific disease diagnosis cannot be made by motility studies of the small bowel, the functional integrity is revealed. The normal occurrence of the essential patterns and periods of motility and the absence of distinctly abnormal patterns evidence preserved function, whereas the opposite indicates clinically significant dysmotility. Certain motility patterns are occasionally seen both in health and disease, and increased prevalence indicates a moderate dysfunction of yet unclear significance. Bacterial overgrowth with Gram-negative bacilli is the consequence of severe small bowel dysmotility, and a diagnosis that can be predicted by a motility study. Testing can be useful in the clinical management of paediatric and adult patients also by predicting the prognosis and response to enteral nutrition and medical therapy. Further studies are, however, needed to take full advantage of motility testing in clinical practise.

Review article: an integrated approach to the irritable bowel syndrome

Our understanding of the pathophysiology of irritable bowel syndrome (IBS) has evolved from a disorder of motility to a more integrated understanding of enhanced motility and visceral hypersensitivity associated with brain-gut dysfunction. Psychosocial factors contribute to the predisposition, precipitation and perpetuation of IBS symptoms, and affect the clinical outcome. Newer brain imaging techniques (e.g. PET, fMRI) may help us understand the relationship between altered emotional states with pain enhancement and other gastrointestinal symptoms. Diagnosis using symptom-based (e.g. Rome) criteria and a conservative diagnostic approach is recommended. Treatment is based on an effective physician-patient relationship and a combined pharmacological and behavioural approach. Newer medications acting at the 5-HT receptor may help in reducing pain and bowel dysfunction. For more severe pain, antidepressants may be considered.

The role of psychological and biological factors in postinfective gut dysfunction

BACKGROUND

Both psychological and physiological disturbances have been implicated in the aetiopathogenesis of irritable bowel syndrome (IBS).

AIMS

To investigate how the psychological factors act, and the involvement of infective and physiological factors.

METHODS

Consecutive patients hospitalised for gastroenteritis reported life events for the previous 12 months, and past illness experiences on standardised questionnaires. They also completed psychometric questionnaires for anxiety, neuroticism, somatisation, and hypochondriasis. In some patients, rectal biopsy specimens were obtained during the acute illness and at three months postinfection.

RESULTS

Ninety four patients completed all questionnaires: 22 patients were diagnosed with IBS after their gastroenteritis (IBS+), and 72 patients returned to normal bowel habits (IBS-). IBS+ patients reported more life events and had higher hypochondriasis scores than IBS- patients. The predictive value of the life event and hypochondriasis measures was highly significant and independent of anxiety, neuroticism, and somatisation scores, which were also elevated in IBS+ patients. Rectal biopsy specimens from 29 patients showed a chronic inflammatory response in both IBS+ and IBS- patients. Three months later, specimens from IBS+ patients continued to show increased chronic inflammatory cell counts but those from IBS- patients had returned to normal levels. IBS+ and IBS- patients exhibited rectal hypersensitivity and hyper-reactivity and rapid colonic transit compared with normal controls, but there were no significant differences between IBS+ and IBS- patients for these physiological measurements.

CONCLUSION

Psychological factors most clearly predict the development of IBS symptoms after gastroenteritis but biological mechanisms also contribute towards the expression of symptoms.

Colonic drug targeting

Specific targeting of drugs to the colon is recognized to have several therapeutic advantages. Drugs which are destroyed by the stomach acid and/or metabolized by pancreatic enzymes are slightly affected in the colon, and sustained colonic release of drugs can be useful in the treatment of nocturnal asthma, angina and arthritis. Treatment of colonic diseases such as ulcerative colitis, colorectal cancer and Crohn's disease is more effective with direct delivery of drugs to the affected area. Likewise, colonic delivery of vermicides and colonic diagnostic agents require smaller doses. This article is aimed at providing insight into the design considerations and evaluation of colonic drug delivery systems. For this purpose, the anatomy and physiology of the lower gastrointestinal tract are surveyed. Furthermore, the biopharmaceutical aspects are considered in relation to drug absorption in the colon and hence various approaches to colon-specific drug delivery are discussed.

Measurement of gastrointestinal motility in the GI laboratory

Current tests of gastric and small intestinal motor function provide relevant physiological information, but their clinical utility is controversial. This article reviews the current procedures, indications, significance, pitfalls, and guidelines for gastrointestinal motility measurements by scintigraphy, gastroduodenojejunal manometry, and surface electrogastrography in humans. Methods included review of literature and discussions in closed and open fora among investigators, including presentations for peer review at focused (Iowa City American Motility Society Symposium, December 1995) and national meetings (American Gastroenterological Association, May 1996, and American Motility Society, September 1996). The current tests are generally complementary; scintigraphy is typically the first test in the evaluation of gastric motor function and often confirms the clinical suspicion of dysmotility. Manometry identifies patterns suggestive of myopathy, neuropathy, or obstruction but may be most helpful when it shows entirely normal findings, because manometry helps in part to exclude dysmotility as a cause of symptoms. Electrogastrography may identify dysrhythmias or failure of signal power to increase postprandially; rhythm abnormalities may be independent of impaired emptying among dyspeptic patients. The best validated and clinically most significant results pertain to transit tests; manometry may contribute importantly to the diagnostic process; and the significance of electrogastrography remains to be fully elucidated.

Is functional dyspepsia just a subset of the irritable bowel syndrome?

To determine whether functional dyspepsia and irritable bowel syndrome are different entities, epidemiological data, factor analysis studies, physiological data and associated psychological symptoms were reviewed. Between 30% and 60% of patients with either diagnosis also meet the criteria for the other diagnosis, a level greater than expected to occur by chance but not sufficient to infer an identity. Most factor analysis studies identify independent clusters of symptoms corresponding to functional dyspepsia and irritable bowel syndrome. Visceral hypersensitivity is seen throughout the gastrointestinal tract in both disorders, but the motility patterns seen in association with functional dyspepsia (principally antral hypomotility and delayed gastric emptying) differ from the motility patterns seen in irritable bowel syndrome. Psychological symptoms are similar in these two disorders but are not believed to be aetiological for either of them. Thus, based on a factor analysis of gastrointestinal symptoms and differences in intestinal motility, functional dyspepsia and irritable bowel syndrome appear to be different entities.

Abnormal vagal cholinergic function and psychological behaviors in irritable bowel syndrome patients: a hospital-based Oriental study

Irritable bowel syndrome (IBS) patients in Western countries usually manifest autonomic nerve dysfunctions and abnormal psychological behaviors. The purpose of this study was to assess whether Oriental IBS patients with predominant bowel symptoms also exhibited similar abnormalities. We enrolled 40 IBS patients from the outpatient clinic and 20 controls with normal daily bowel habit for study. The IBS patients were further divided according to their predominant bowel habit: 20 were constipation-predominant and 20 were diarrhea-predominant. Sympathetic function was evaluated by sympathetic skin response (SSR) while vagal cholinergic function was determined by measuring R-R interval variation (RRIV) in electrocardiography during rest and deep breathing. Psychological parameters were assessed by scales of the Minnesota Multiphasic Personality Inventory (MMPI) and the Hopkins Symptom Checklist (HSCL-90). IBS patients, despite their bowel habit, showed normal SSR response. RRIV during deep breathing was significantly lower in constipation-predominant IBS patients than in controls or diarrhea-predominant IBS patients (16.5+/-3.1% vs 20.5+/-4.8% and 21.5+/-4.6%, P < 0.001). IBS patients also exhibited abnormal MMPI measuring scores on depression, hysteria, paranoia, and masculinity/femininity scales. In addition, they also had more severe psychological distress in the items of HSCL-90 measurement. In conclusion, vagal dysfunction characterizes Oriental constipation-predominant IBS patients seeking medical help. Abnormal psychoneurotic profiles also exist in these IBS patients, irrespective of their bowel habits.

Postprandial plasma 5-hydroxytryptamine in diarrhoea predominant irritable bowel syndrome: a pilot study

BACKGROUND

Increased concentrations of 5-hydroxytryptamine (5-HT) can be detected in the systemic circulation after a meal and may be involved in the physiological control of gastrointestinal motility. Abnormalities of 5-HT release after a meal might explain some of the postprandial symptoms associated with the irritable bowel syndrome (IBS).

AIM

To investigate the effect of a standard meal on plasma 5-HT and urinary 5-hydroxyindole acetic acid (5-HIAA) concentrations in patients with diarrhoea predominant IBS and in healthy volunteers.

METHODS

After an overnight fast, six volunteers and five patients with IBS were given a carbohydrate-rich meal. Blood and urine samples were taken before and for four hours after the meal. Platelet-poor plasma 5-HT and urinary 5-HIAA were analysed by reversed phase high performance liquid chromatography with fluorometric detection. 5-HIAA was expressed as a ratio with urinary creatinine concentration, which was measured by spectrophotometry.

RESULTS

During the four hour postprandial period, 5-HT concentrations were significantly higher in patients with IBS than in healthy volunteers at 0.5 hours (p < 0.05), 2 hours (p < 0.05) and 2.5 hours (p < 0.05). 5-HT was not detected in the plasma in the fasting state in patients or volunteers. Median peak 5-HT in patients with IBS (359 (198-796) nmol/l) was significantly greater than volunteers (83 (7-190)) (p < 0.05). "Area under the curve" for 5-HT detection was greater for patients with IBS (317 (138-771)) than for healthy volunteers (51 (4-129); p < 0.05). The duration of the 5-HT peak was significantly longer in patients with IBS (3 (1-3) hours) than in the healthy volunteers (1 (1-1) hours; p < 0.01). Postprandial urinary median 5-HIAA values in controls (5.6 (5.5-5.8) mumol/mmol creatinine) and patients with IBS (3.0 (2.5-6.8) mumol/mmol creatinine) were not significantly different from preprandial values (controls: 5.9 (5.5-6.6) mumol/mmol creatinine; patients with IBS: (6.2 (2.4-9.3) mumol/mmol creatinine).

CONCLUSION

These findings indicate that there may be a difference in the way that 5-HT is released in patients with diarrhoea predominant IBS, and could suggest a possible role for 5-HT in the postprandial symptoms of these patients.

Gastroparesis and small bowel dysmotility in irritable bowel syndrome

Alterations in both gastric emptying (GE) and small bowel motility have been reported in irritable bowel syndrome (IBS); the relationship, however, between these different measures of upper gut motor function in IBS has not been assessed. The aims of this study were therefore: (1) to compare the prevalence and characteristics of altered small bowel motility in IBS patients with and without delayed GE; and (2) to assess the interrelationships between fasting and postprandial small bowel motility in IBS, accounting for delayed GE. Forty-four IBS patients and 25 healthy controls underwent 24 hr ambulant recording of interdigestive and digestive small bowel motility. On a separate occasion the IBS patients had GE of both solids and liquids measured by a dual-isotope scintigraphic technique. Thirty-nine percent of IBS patients had delayed GE. Patients with normal GE had no interdigestive small bowel abnormalities. However, in patients with delayed GE fasting phase II burst frequency was higher than in controls [median 0.21/hr (IQR 0.15-0.34) vs 0.06/hr (0-0,16), P = 0.004]. Postprandially, abnormal phase III-like activity was higher in diarrhea-predominant IBS patients (0-0.08/hr vs 0/hr, P = 0.01), than in patients with normal GE or controls. Furthermore, IBS patients with delayed GE did not have the normal correlation between fasting and postprandial motor parameters (percentage occurrence of clustered contractions, postprandial pattern duration vs preceding MMC cycle length). In conclusion, small bowel motor dysfunction occurs more frequently in IBS patients with concomitant gastroparesis than in patients with normal GE. These findings provide further evidence that a neuropathic process may contribute to the pathogenesis of IBS in a subgroup of IBS patients.

Rapid gastric emptying in patients with functional diarrhea

OBJECTIVE

To analyze our experience in patients with chronic diarrhea by using a noninvasive transit study that measures gastric emptying as well as small bowel and colonic transit.

MATERIAL AND METHODS

Results from 94 consecutive transit tests, for which diarrhea was the main indication, were reviewed and correlated with the final classification of patients as having an organic or nonorganic disorder.

RESULTS

Sixty patients were considered to have a nonorganic cause of diarrhea, of whom 15 had previously undergone cholecystectomy. The other 34 patients were considered to have diarrhea on the basis of an organic diagnosis. Gastric emptying was more often rapid in patients with a nonorganic cause (P < 0.05), but not if cholecystectomy had been performed previously. Small bowel transit was fast more often in patients with organic diarrhea than in those with no organic cause of the diarrhea (P < 0.05); colonic transits showed no significant differences among groups.

CONCLUSION

The findings implicate a motor abnormality of the upper gut, rapid gastric emptying, as a pathophysiologic mechanism of functional bowel disorders with diarrhea. The results imply that additional prospective observations should be worth-while.

Belching, bloating, and flatulence. How to help patients who have troublesome abdominal gas

Gaseous belching, bloating, and flatulence are common complaints. These symptoms may herald the onset of important and treatable gastrointestinal diseases or may represent functional bowel disorders. The clinical challenge is to identify a cause so as to exclude serious gastrointestinal diseases and provide symptomatic relief. Detailed history taking and examination provide the basis for appropriate testing that may provide vital clues. Among otherwise healthy patients, intolerance to lactose or other food items is a common source of symptoms. This cause can be evaluated noninvasively using the breath hydrogen test. A clear understanding of the underlying pathophysiology paves the way for a rational approach to treatment, such as withdrawal of an offending food item, enzyme supplementation, simple reassurance, or psychotherapy.

Review article: irritable bowel syndrome

Irritable bowel syndrome is a disease that can be diagnosed positively on the basis of an established series of criteria and limited exclusion of organic disease. It is the most common disease diagnosed by gastroenterologists and affects about 20% of all people at any one time. Symptoms fluctuate, and the overall prevalence rate is relatively constant in Western communities. Ten per cent of patients present to their physicians; the illness has a large economic impact on health-care utilization and absenteeism. Irritable bowel syndrome is a biopsychosocial disorder in which three major mechanisms interact: psychosocial factors; altered motility; and/or sensory function of the intestine. Management of patients is based on positive diagnosis of the symptom complex, limited exclusion of underlying organic disease and institution of a therapeutic trial. If patient symptoms are intractable, further investigations are needed to exclude significant motility or other disorders. Symptomatic treatment includes fibre for constipation, loperamide for diarrhoea and low-dose antidepressants or infrequent use of antispasmodics for pain; novel pharmacological agents, psychotherapy and hypnotherapy are being evaluated.

Variability of gastrointestinal transit in healthy women and men

BACKGROUND AND AIMS

Measurements of gastrointestinal transit are made in clinical and research gastroenterology, yet their intrinsic variability is not well characterised. In particular, an influence of hormones on transit has been proposed as the basis for gastrointestinal symptoms that vary with the menstrual cycle. Our aims were to quantify individual differences in transit during the menstrual cycle in healthy women and to compare these with the intrinsic variability in healthy men.

METHODS

On two occasions, whole gut transit was assessed scintigraphically and colonic transit quantified by radio-opaque markers. Thirty two healthy volunteers (12 women, 20 men) were studied, women during the follicular and luteal phases, men twice within a similar four week period. Diets and exercise were standardised prior to and during both studies.

RESULTS

Colonic transit was significantly faster in men, and postlag gastric emptying was also more rapid; other indices of regional transit were not different between the sexes. Total colonic transit time was equally well reflected by the scintigraphic and radio-opaque marker methods. Important intraindividual differences were noted in both sexes. The variances in our samples predicted an 80% chance of detecting (with 95% confidence) a mean effect of menstrual hormones on transit that was in the same range as the intrinsic variation in men.

CONCLUSIONS

Colonic transit was faster in men than in women. Although group means in the two studies were almost identical, single assessments of transit in subjects sometimes exhibited considerable variability, implying broad biological variations. Given this intrinsic variability, the influence of menstrual hormones on gastrointestinal transit must be small and of doubtful clinical significance.

How well does stool form reflect colonic transit?

BACKGROUND

Watery stools are equated with rapid and hard stools with slow intestinal transit; however, the relation between stool form and transit through specific regions of the gut is not clear cut. In addition, more information is needed on interindividual variability of these measurements.

AIM

To examine the relations between stool form and gastric emptying, small bowel and colonic transit.

METHODS

Regional gut transit was assessed scintigraphically and segmental colonic transit was also quantified by radio-opaque markers. On two occasions, 32 healthy volunteers (12 men, 20 women) were studied, women during the follicular and luteal phases of menstruation, men twice within a similar four week period. Diets were standardised and stool form was recorded on a seven point scale.

RESULTS

Women had significant harder stools; hard stools were correlated significantly with slow transit and loose stools with fast transit through the colon.

CONCLUSIONS

Stool form could not be related to gastric emptying or small bowel transit.

Ambulatory 24-hour jejunal motility in diarrhea-predominant irritable bowel syndrome

BACKGROUND

Whether small-bowel motility is abnormal in the irritable bowel syndrome (IBS) is a controversy at present. The aim of our study was to compare ambulatory long-term jejunal motility in 35 IBS patients with predominant diarrhea to normal values obtained in 50 healthy controls.

METHODS

Twenty-four-hour motility was recorded in the proximal jejunum with a portable datalogger and tube-mounted miniature pressure sensors. Fasting motility in the waking (W) and sleeping (S) state and the motor response to a standardized evening meal of 600 kcal underwent visual and computer-aided analysis.

RESULTS

Fasting motility in patients showed migrating motor complex (MMC) cycles of normal length and composition. Uninterrupted runs of discrete clustered contractions during phase II (W) occurred in 57% of patients and 52% of controls but had a significantly longer duration in patients (33 +/- 5 versus 19 +/- 7 min; p < 0.005). During phase II (W) IBS patients had an increase in aborally propagated contractions (41 +/- 2% versus 35 +/- 2%; p < 0.01) and higher contraction amplitudes (26.3 +/- 0.8 versus 23.0 +/- 0.5 mm Hg; p < 0.01). Similar differences were obtained during postprandial motility (47 +/- 3% versus 39 +/- 3%; p < 0.01, and 25.9 +/- 0.9 versus 23.8 +/- 0.05 mm Hg; p < 0.02). In three patients (8.6%) disturbed aboral migration of phase III and irregular burst activity, manometric features of chronic idiopathic intestinal pseudo-obstruction, were identified. Whereas 57% of patients had an entirely normal 24-h manometry, 43% had at least one finding not present in any healthy control.

CONCLUSION

Small-intestinal motility is frequently but not universally abnormal in diarrhea-predominant IBS. The abnormal manometric findings are heterogeneous and range from subtle quantitative changes to severe qualitative abnormalities resembling chronic idiopathic intestinal pseudo-obstruction in a small subset of patients.

Surgery for constipation: a review

PURPOSE

Constipation is related to intestinal motility disorders (colonic inertia (CI)), pelvic floor disturbances (pelvic outlet obstruction), or a combination of both problems. This review summarizes the physiologic and pathophysiologic changes in patients with intractable constipation and gives an overview of surgical treatment options.

RESULTS

Although subtotal colectomy with ileorectal anastomosis is the best surgery for CI, there are still approximately 10 percent of patients who will complain of pain and constipation. A completion proctectomy and an ileoanal pouch procedure may be a viable option in a highly select group of patients. In patients with megabowel, reported results are mixed. Subtotal colectomy, partial colectomy for megacolon, and the Duhamel procedure for megarectum have all been reported with variable results. In patients with an isolated distended sigmoid colon, sigmoid colectomy has achieved good results. Anorectal myectomy has not been proven to be successful in the long term. However, in patients with adult short segment Hirschsprung's disease, myectomy can be successful. Patients with pelvic outlet obstruction can be successfully treated with biofeedback. In a small group of patients with a rectocele or a third degree sigmoidocele, surgical intervention yields a high success rate. Division or resection of the puborectalis muscle is not recommended. In patients with a mixed pattern of CI and pelvic outlet obstruction, surgical intervention alone is often not successful. These patients achieve better results by conservative treatment of pelvic outlet obstruction, followed by a colectomy.

CONCLUSION

Surgical intervention for patients with intractable constipation is rarely necessary. However, thorough preoperative physiologic testing is mandatory for a successful outcome.

Colonic motility in health and disease

Being the final pathway for chyme and digestive residues, the colorectum influences bowel function critically. The most important and relevant symptoms of colonic dysfunction are diarrhea, constipation, urgency, and pain. Despite the effects of many investigators, over several decades, the motor physiology of the human colon is still relatively obscure. Most is known about patterns of colonic transit. In practice, measurements of transit are the best characterized and most widely available tests of colonic motor function. Colonic hypersensitivity, implying an abnormality of afferent signaling, is assuming greater importance in the pathophysiology of conditions as common as IBS and inflammatory bowel disease.

Whole-gut transit scintigraphy in the evaluation of small-bowel and colon transit disorders

Scintigraphic methods for performing gastric emptying and colon transit studies are now well standardized. Although not as well established, several methods have been proposed for measuring small-bowel transit. The measurement of orocecal transit time appears to be a practical scintigraphic measurement of small-bowel transit. When combined into a single test of gastric emptying, small-bowel, and colon transit, whole-gut transit scintigraphy is an important, noninvasive tool for documenting dysmotility of any segment of the gastrointestinal tract. Despite attempts to simplify the study, whole-gut transit scintigraphy still requires a significant commitment of time and equipment. As with other gastrointestinal studies, each laboratory must determine which protocol best fits its clinical needs, equipment, and staffing. Attention must be paid to adhere to established protocols, or normal values will need to be determined for each laboratory. Despite these difficulties, whole-gut transit scintigraphy now represents an important clinical tool for the evaluation of patients with a wide range of abdominal complaints.

Role of nuclear medicine in evaluating patients with suspected gastrointestinal motility disorders

Functional symptoms caused by gastrointestinal motility disorders are relatively common in the general population. Knowledge of the relationship between symptoms and the underlying gastrointestinal dysmotility provides physicians with a framework for successful evaluation and treatment of patients with possible motor disorders of the gastrointestinal tract. Scintigraphy provides for noninvasive and quantitative assessment of physiological transit throughout the gastrointestinal tract, and it is extremely useful for diagnosing gastrointestinal motor dysfunction. The wide range of scintigraphic studies now available supplement other diagnostic tests for evaluation of all segments of the gastrointestinal tract.

Scintigraphic measurement of ileocaecal transit in irritable bowel syndrome and chronic idiopathic constipation

This study investigated the hypothesis that some features of functional gastrointestinal disorders may be associated with abnormalities of ileocaecal transit by measuring ileocaecal transit using a scintigraphic technique in 43 patients with chronic constipation, 20 patients with irritable bowel syndrome (IBS), and 18 control subjects. Subjects ingested enteric coated capsules, which delivered 111-indium radionuclide to the distal ileum. Gammacamera images were acquired at hourly intervals until caecal filling was complete. Ileocaecal transit was defined as the time between peak scintigraphic activity in the terminal ileum and peak activity in the caecum. The mean (SD) ileocaecal transit of 103 (50) minutes in patients with IBS was significantly faster than that in control subjects (mean (SD) ileocaecal transit 174 (78) minutes, p < 0.002). There were no significant differences in ileocaecal transit between patients with chronic idiopathic constipation and the control subjects, or between patients with constipation predominant and diarrhoea predominant IBS. This study developed a practical scintigraphic method of measuring ileocaecal transit. The rapid ileocaecal transit in both the constipation and diarrhoea predominant forms of IBS suggests that bloating may not after all result from delayed ileal emptying.

Irritable bowel syndrome. Managing the patient with abdominal pain and altered bowel habits

Irritable bowel syndrome is a common complex of syndromes thought to be generated by a motility or sensory disturbance of the gastrointestinal tract. It is a frequent cause of chronic abdominal pain and altered bowel habits. Patients who seek medical attention for irritable bowel syndrome often do so because of psychosocial factors. Therapy remains largely empirical, directed toward the relief of symptoms in the context of a supportive physician-patient relationship.

Use of geometric center and parametric images in scintigraphic colonic transit studies

BACKGROUND/AIMS

Scintigraphic studies give detailed information on colonic transit. In this study, several methods of presenting such data were compared and discussed. The aim of the study was to evaluate the role of geometric center (GC) and parametric images in interpretation of colonic transit studies.

METHODS

Segmental colonic transit was measured in 117 patients: 50 with constipation, 24 with irritable bowel syndrome, 22 with fecal incontinence, 14 who were postsurgery, and 7 normal volunteers. 111In-labeled resin was administered in a pH-sensitive capsule, and images were acquired for 3 days. The percentage of activity in four regions of colon and in the feces was measured.

RESULTS

Five patterns of colonic transit were identified (16 rapid transit, 48 intermediate, 14 generalized delay, 5 left-sided delay, and 34 right-sided delay). The geometric center (sum of fraction of activity x region number) was calculated at each time point. Using the geometric center, the groups could be differentiated (P < 0.01) except for those with left-sided delay. In individual patients, patterns of colonic transit could not be determined using the geometric center alone. Gray-scale presentation of percent activity in each region (parametric images) allowed patterns of colonic transit to be identified in individuals.

CONCLUSIONS

Use of the geometric center is suitable for comparison of groups of patients, whereas parametric images identify patterns in individual patients.

A 5HT3 antagonist corrects the postprandial colonic hypertonic response in carcinoid diarrhea

BACKGROUND/AIMS

Carcinoid patients show a hypertonic colonic motor response postprandially. Ondansetron reduces postprandial colonic tone in health. It was hypothesized that ondansetron, a selective 5HT3 antagonist, corrects the colonic motor response to eating in carcinoid diarrhea.

METHODS

The effects of ondansetron and placebo on fasting and postprandial colonic tone and motility in 10 patients with carcinoid diarrhea were compared using a manometry-barostat assembly positioned in the upper descending colon.

RESULTS

Fasting colonic tone and motility indices were similar in the placebo and ondansetron groups; ondansetron did not affect fasting motility. The placebo group showed a significant reduction in barostat balloon volume (signifying increased tone) from 207 +/- 29 mL (mean +/- SEM) during fasting to 106 +/- 14 mL postprandially (P = 0.01). With ondansetron, a tonic colonic response was induced postprandially (198 +/- 37 mL to 151 +/- 30 mL; P = 0.053). However, the increment in tone in the ondansetron group (23% +/- 7%) was significantly lower than in the placebo group (48% +/- 5%; P = 0.02) and was similar to that observed in untreated healthy subjects (24% +/- 3%). Postprandial manometric pressure activity increased significantly in the placebo group (P = 0.01); in the ondansetron group there was a trend (P = 0.09) to increased phasic activity.

CONCLUSIONS

Ondastetron reduces the postprandial colonic hypertonic response in carcinoid diarrhea to levels previously reported in health; further clinical studies of this class of antagonists in carcinoid diarrhea appear warranted.

Influence of antidepressants on whole gut and orocaecal transit times in health and irritable bowel syndrome

BACKGROUND

Antidepressants are used in the treatment of irritable bowel syndrome but it is unclear whether any symptomatic improvement is due solely to correction of an associated affective disorder, or whether these drugs have effects on bowel function which may be of therapeutic benefit. Intestinal transit is known to be abnormal in some irritable bowel syndrome patients.

METHODS

We have studied the effects of imipramine, a tricyclic antidepressant with mixed pharmacological properties, and paroxetine, a selective 5-hydroxytryptamine re-uptake inhibitor, on intestinal transit times.

RESULTS

Median (range) whole gut transit time was lower in 10 diarrhoea-predominant irritable bowel syndrome patients, 22.2 (3.6-51.6) h, compared to 28 control subjects 39.6 (7.2-68.4) h, (P < 0.05). Similarly, orocaecal transit time was shorter at 55 (30-90) min in diarrhoea-predominant irritable bowel syndrome patients compared to 75 (40-150) min in controls, (P < 0.05). Four days' administration of imipramine increasing to a daily dose of 100 mg prolonged both orocaecal and whole gut transit times in 12 control subjects and six diarrhoea-predominant irritable bowel syndrome patients. In contrast, 30 mg paroxetine daily for 4 days reduced orocaecal transit time in ten controls and eight irritable bowel syndrome patients, but had no effect on whole gut transit time.

CONCLUSION

Short-term administration of antidepressants alters intestinal transit, but the selective 5-hydroxytryptamine re-uptake inhibitor, paroxetine, has different effects to the tricyclic drug, imipramine. These effects on transit precede any effects on mood. Although there is a high prevalence of affective disorder in irritable bowel syndrome clinic patients, these drugs may have additional therapeutic actions on the gut. These actions might be taken into account when prescribing antidepressants in irritable bowel syndrome.

Ambulatory small intestinal motility in 'diarrhoea' predominant irritable bowel syndrome

Dysmotility of the duodenum and proximal jejunum has been reported in patients with irritable bowel syndrome. This study extended these findings by recording fasting ambulatory motility from electronic strain gauge sensors sited in the jejunum and ileum of eight diarrhoea predominant irritable bowel syndrome patients and 12 healthy controls. During the day, periodicity of migrating motor complexes mean (SEM) did not differ between patients (92 (10) min) and controls (85 (7) min). At night, periodicity was shorter in both patients and controls, and the daytime dominance of phase II was replaced by phase I. In both groups, aboral progression of phase III fronts was associated with a slowing of propagation velocity and maximum contractile rate, but an increase in mean amplitude of contraction. Discrete clustered contractions were seen in seven patients and 10 controls occupying 14 and 16% of daytime phase II activity, respectively. Pain episodes were not associated with any specific motility patterns. Despite the lack of motility differences between the two groups, orocaecal transit time in the irritable bowel syndrome patients was shorter at 57 (9) min than in the controls, 82 (6) min (p < 0.05). This ambulant study has failed to show any abnormalities of fasting small intestinal motility that might distinguish diarrhoea predominant irritable bowel syndrome patients from healthy controls.

Pathophysiology of colonic motility disorders

When no identifiable organic cause for colonic symptoms can be found, it is easy for the busy clinician to label the patient neurotic. It is evident that many of these "functional" disorders do reflect an underlying motility disorder, although our understanding is far from clear. However, currently, patients with severe constipation are evaluated in a much more rational manner and, as a consequence, are offered a reasonable therapeutic approach that can be predicted to have a good chance for success. We can hope that as our understanding of irritable bowel syndrome is strengthened, treatment will become more efficacious than the unproved and costly medications that are in use currently. Until dietary modification becomes commonplace, it is unlikely that the incidence of diverticular disease or its complications will change. Already, our understanding of ileus has allowed us to realize the benefits of laparoscopic surgery, and as our knowledge of the various gut hormones and the inhibitory role that some play in intestinal motility grows, ileus, and its resulting prolongation of hospital stay, may become less problematic.

The effect of beta-adrenoreceptor agonists and antagonists on fructose absorption in man

To explore the effect of beta-adrenoreceptor stimulation and blockade on the extraction of monosaccharide from the upper gut, we first established the malabsorption threshold in 26 normal volunteers using a series of test meals containing varying proportions of fructose and glucose. Incomplete small intestinal extraction and consequent arrival of carbohydrate into the caecum was identified by a rise in exhaled breath hydrogen concentration. The malabsorption threshold varied between individuals from 30 to 80 g fructose (median 40 g) but was reproducible within individuals, with 90% agreement of repeat studies. The malabsorption threshold for an individual was unrelated to body height (tau = 0.007, P > 0.05) or weight (tau = 0.003, P > 0.05) but correlated closely with time to onset of the breath hydrogen rise of a standard meal (tau = 0.70, P < 0.001). Administration of the beta-adrenoreceptor antagonist propranolol (160 mg) reduced the quantity of fructose required to exceed the malabsorption threshold from 45, 30-60 (median and range) to 40, 30-50 g (P = 0.03); administration of the beta-adrenoreceptor agonist isoprenaline (0.015 micrograms.kg/min) increased the quantity of fructose required to exceed the malabsorption threshold by 10 g (55 (50-90) g; P < 0.02). The effect of both drugs correlated closely with their transit effect (tau = 0.79, P < 0.01). A beta-adrenoreceptor mediated pathway thus appears to be capable of influencing the extraction of monosaccharide from the small intestine in normal subjects both under resting and stimulated conditions, probably acting via an effect on upper gastrointestinal motility.

Review article: adrenergic control of motor and secretory function in the gastrointestinal tract

The role that the sympathetic nervous system plays in modulating physiological processes in the gastrointestinal tract is becoming clearer. It is now known that motor, secretomotor and vasomotor activity are all modulated independently by the system. Adrenoreceptor stimulation appears to reduce intestinal contraction (except at sphincters), both via alpha-receptors which inhibit neurotransmitter release and also by a direct beta-receptor mediated action on smooth muscle. There is also evidence for tonic activity in the beta-adrenergic pathway, since beta-antagonists tend to increase contraction pressures. In animals alpha-receptor-mediated pathways modulate fluid and electrolyte absorption, and alpha-adrenergic agonists enhance net absorption and reduce net secretion. In man there is also evidence for a beta-adrenergic pathway which controls secretomotor function. Carbohydrate absorption appears to be dependent on activity in a beta-adrenergic pathway, although this may be an indirect effect of changes in motor function. The time course of changes of both secretomotor and motor activity, induced by modulating sympathetic or adrenergic input, differ from the vascular changes indicating that the effects occur independently of each other. The gastrointestinal response to stressors is mediated, in part at least, by the sympathetic nervous system. Differences between individuals are likely to prove important. Since the sympathetic nervous system regulates gastrointestinal function both in the basal state and under stressful conditions, it will have effects on pathophysiological responses. Modification of such responses is likely to ameliorate symptoms, as has already been found for alpha-2-adrenergic agonists which have an antidiarrhoeal action.

Transit through the proximal colon influences stool weight in the irritable bowel syndrome

The inherent variability of symptoms and motor abnormalities in patients with the irritable bowel syndrome has hampered the demonstration of motor abnormalities that could underlie symptoms. The aim in the current study was to evaluate whether altered regional capacitance or transit of solid residue through the unprepared human gut were factors in the diarrhea of patients with the irritable bowel syndrome. In 10 such patients and in 5 healthy controls, gastric and small bowel transits were evaluated scintigraphically by means of a mixed meal containing 99mTc-labeled resin pellets. Regional colonic transit was quantitated by 111In-labeled pellets delivered to the ileocecal region by a pH-sensitive, methacrylate-coated capsule. Symptomatic patients did not have significantly altered gastric or small bowel transits, but colonic transit was accelerated in 7 of 10 persons with the irritable bowel syndrome (P less than 0.02), in the proximal colon of five patients and in the left colon of two patients. The 24-hour stool weight was positively correlated with the rate at which solid residue emptied from the ascending and transverse colons (r = 0.78; P less than 0.01). There was also an inverse relationship between emptying rates and maximal volumes accommodated by the proximal colon (r = -0.58; P less than 0.05), although the maximum volume of the proximal colon was not significantly different in patients and healthy subjects. Thus, accelerated transit through the proximal colon is a factor in the pathophysiology of the irritable bowel syndrome and influences the stool weight of such patients. The capacitance of the proximal colon presumably influences its storage capacity and, hence, the rate at which it empties.

Gastric emptying and dyspeptic symptoms in the irritable bowel syndrome

Many patients with irritable bowel syndrome (IBS) have symptoms suggestive of disturbances in gastric emptying, but so far no abnormalities in gastric emptying have been demonstrated in these patients. We studied gastric emptying of a solid meal with a 99mTc-labeled pancake in 16 healthy volunteers (8 women and 8 men; age, 20-33 years; mean age, 25 years) and 16 predominantly constipated IBS patients (10 women and 6 men; age, 17-43 years; mean age, 25 years). The incidence and severity of the symptoms nausea, vomiting, early satiety, and pain in the upper abdomen were scored. The duration of the lag phase of gastric emptying of the solid meal did not differ between the groups (controls, 16.6 +/- 4.7 min; IBS patients, 22.2 +/- 14.7 min). In normal subjects lag phase duration and emptying rate were correlated (r = 0.49, p greater than 0.05); in the IBS patients they were not. Post-lag gastric emptying of the solid meal was slower (p less than 0.01) in the IBS patients (0.58 +/- 0.24%/min) than in the control subjects (0.85 +/- 0.24%/min). No correlations were found, however, between the emptying rate and the severity of the upper abdominal symptoms. This study is the first to demonstrate that gastric emptying is delayed in IBS patients. This abnormality, however, appears not to be the major determinant of the upper abdominal symptoms often present in these patients.

Role of fasting gastrointestinal motility in the variability of gastrointestinal transit time assessed by hydrogen breath test

Gastrointestinal motility and transit time, measured by the hydrogen breath test, were simultaneously assessed in six healthy volunteers. Each subject underwent six studies on separate days. On each day motility was measured in the gastric antrum, duodenum, and proximal jejunum and 15 g of lactulose was given either by mouth during gastric phases I, II, III of the motor migrating complex or infused duodenally during duodenal phases I, II, III, one phase being studied each day in random order. Fasting activity was not interrupted by the lactulose. The lactulose transit time decreased significantly from a peak with phase I through phase II to a minimum with phase III (mean (SD) 155 (26) min v 120 (10) min v 94 (14) min, p less than 0.001). Similar results were noted when the lactulose was instilled intraduodenally (156 (23) min v 125 (19) min v 100 (17) min, p less than 0.001). No correlation was found between motility index and transit. These results suggest that different phases of fasting gastrointestinal motility are major determinants of the transit time estimated by the hydrogen breath test and explain the variability of this test in practice.

Physiology and pathophysiology of colonic motor activity (2)

The basic motor function of the colon is to mix and knead its contents, propel them slowly in the caudad direction, hold them in the distal colon until defecation, and provide a strong propulsive force during defecation. Infrequently, it also produces mass movements in the proximal colon. These motor functions are achieved in most species by three different types of contractions: the individual phasic contractions that include the short- and long-duration contractions, organized groups of contractions that include the migrating and nonmigrating motor complexes, and special propulsive contractions (giant migrating contractions). The spatial and temporal patterns of all of these contractions are controlled by myogenic, neural, and chemical control mechanisms. The individual phasic contractions are highly disorganized in time and space in the colon. For this reason, they are effective in mixing and kneading and slow distal propulsion. The underlying cause of the disorganization of short duration contractions is the irregularity in the frequency and waveshape of colonic electrical control activity and its phase unlocking throughout the colon. The individual contractions in many species occur in cyclic bursts called contractile states. At least in some species, these contractile states exhibit mostly caudad and sometimes orad migration. However, there are also nonmigrating or randomly migrating contractile states in the colon. These two patterns of contractile states are called colonic migrating motor complexes and colonic nonmigrating motor complexes, respectively. The giant migrating contractions provide the strong propulsive force for defecation and mass movements. The neural control of colonic contractions is organized at three levels--enteric, autonomic, and central. The enteric nervous system contains cholinergic and peptidergic neurons and plays a major role in the control of colonic contractions. The autonomic nerves, the vagi, pelvic, lumbar colonic, hypogastric, and splanchnic nerves, seem to continuously monitor the state of the colon and provide a modulatory input when necessary. These nerves play a major role in the reflexive control of colonic motor function. The voluntary input from the central nervous system coordinates the motor activity of the colon, rectum, anal canal and sphincters for orderly evacuation of feces during defecation. The role of acetylcholine, nonadrenaline, and the yet to be completely identified nonadrenergic, noncholinergic neurotransmitter, possibly VIP, in the control of contractions is fairly well established. Besides these, there are several other peptides and chemicals that are localized in the colonic wall; their physiological roles remain unknown. Colonic motor activity has been studied in several disease states. The findings have not always been consistent.(ABSTRACT TRUNCATED AT 400 WORDS)

Small intestinal motility and transit in disease

Disorders of small intestinal motility and transit are becoming increasingly recognized partly as a result of a greater awareness of their existence and partly because suitable diagnostic methods are more widely available. Usually, the neuropathic and myopathic forms can be separated, and gut disease secondary to a generalized neuromuscular disorder can be identified by the clinician. The availability of better non-invasive methods for the diagnosis of disorders of motility and transit would greatly facilitate their management. Treatment must include the restoration and maintenance of nutrition, attempts to improve intestinal motor function and resection of any segments of localized disease. Regrettably, all such measures are ineffective in the severest cases. In the future, a greater understanding of the enteric neural control of the smooth muscle and an ability to manipulate it with novel, specific drugs or peptidergic receptor agonists and antagonists, or electrical pacing, may lead to more effective therapies.

Evidence for hypomotility in non-ulcer dyspepsia: a prospective multifactorial study

A prospective multifactorial study of symptoms and disturbance of gastrointestinal function has been undertaken in 50 patients with non-ulcer dyspepsia. Objective tests including solid meal gastric emptying studies, gastric acid secretion, E-HIDA scintiscan for enterogastric bile reflux, and hydrogen breath studies were carried out in all patients and validated against control data. Gastroscopy and biopsy were carried out in non-ulcer dyspepsia patients only. Non-ulcer dyspepsia patients were categorised on the basis of predominant symptoms as: dysmotility-like dyspepsia (n = 22); essential dyspepsia (n = 14), gastro-oesophageal reflux-like dyspepsia (n = 11); and ulcer-like dyspepsia (n = 3). In the total non-ulcer dyspepsia population, solid meal gastric emptying was delayed (T50 mean (SEM) = 102 (6) minutes (patients) v 64 (6) minutes (controls), (p less than 0.01) and high incidences of gastritis (n = 26) and Helicobacter pyloridis infection (n = 18) were found. An inverse correlation was observed between solid meal gastric emptying and fasting peak acid output (r = -0.4; p less than 0.01). Indeed gastric emptying was particularly prolonged in eight patients (T50 mean (SEM) = 139 (15) minutes) with hypochlorhydria. In the non-ulcer dyspepsia population oral to caecal transit time of a solid meal was delayed (mean SEM = 302 (14) minutes (patients) v 244 (12) minutes (controls) (p less than 0.01]. Seven patients had a dual peak of breath hydrogen suggestive of small bowel bacterial overgrowth. No association was observed between symptoms and any of the objective abnormalities. This multifactorial study has shown that hypomotility, including gastroparesis and delayed small bowel transit, is common in non-ulcer dyspepsia and may be related to other disorders of gastrointestinal function. No relation between symptoms and disorders of function, however, has been shown.

Ispaghula therapy in irritable bowel syndrome: improvement in overall well-being is related to reduction in bowel dissatisfaction

This placebo controlled, double-blind, cross-over trial involving 20 patients was conducted to assess the effect of ispaghula husk on the major bowel symptoms and the whole gut transit time in irritable bowel syndrome (IBS) and to determine if changes in these parameters were related to global improvement. All 20 patients were interviewed at the end of the treatment periods and 14 patients kept concurrent daily records. Ispaghula therapy resulted in improvement in global symptoms and satisfying bowel movements (P less than 0.001) but produced no change in abdominal pain or flatulence. There was a correlation between the improvement of well-being and the number of days of satisfying bowel movements (P less than 0.001) but not with the indexes of pain, stool frequency or changes in the transit time. The easing of bowel dissatisfaction appears to be a major reason for the therapeutic success of ispaghula in IBS.

Effect of mefenamic acid on bowel transit time in healthy adult volunteers

The effect of mefenamic acid on bowel transit time was investigated. Seven healthy adult male subjects of age 39 +/- 2.4 years (mean +/- S.E.M.) received placebo or mefenamic acid (500 mg t.d.s) orally in randomized order for five days, with a 7-day washout between studies. On the third morning after starting the drug they had a meal containing Redi-Brek and baked beans with radio-opaque markers. Small bowel transit time was measured using breath hydrogen, and whole gut transit time was measured using radio-opaque markers. The small bowel transit times were 160 min (median) with placebo and 50 min with mefenamic acid (P less than 0.05). The percentages of appearance of marker in stool within 24 h were 24.9 +/- 11.8 (mean +/- S.E.M.) with placebo and 48.9 +/- 11.7 with mefenamic acid (P less than 0.05). The times of appearance of twenty-fifth marker in stool were 41.0 +/- 4.4 h with placebo and 26.9 +/- 3.2 h with mefenamic acid (P less than 0.05). The total weights of faeces in 72 h were 500.9 +/- 96.2 g with placebo and 657.1 +/- 118.8 g with mefenamic acid (P less than 0.05). Mefenamic acid in therapeutic doses (500 mg t.d.s.) accelerated bowel transit time in healthy subjects.

Prolonged ambulant recordings of small bowel motility demonstrate abnormalities in the irritable bowel syndrome

Continuous 72-h recordings of duodenojejunal contractile activity were obtained from 20 freely ambulant subjects; pressure was detected by two strain-gauge sensors incorporated in a transnasal catheter attached to an encoder and a miniature tape recorder. The subjects were 12 patients with irritable bowel syndrome, 6 of whom were constipation predominant and 6 of whom were diarrhea predominant, and 8 healthy controls. The procedure was well tolerated by all subjects and did not interfere with sleep or normal activity. In all subjects, the diurnal migrating motor complex cycle was characterized by a brief phase 1 and a prolonged phase 2; this was reversed during sleep when phase 2 was virtually absent. All subjects showed a circadian variation in migrating motor complex propagation velocity, and there was no difference in the patterns of motor activity during sleep between any of the groups. During the day, the duration of postprandial motor activity was shorter in irritable bowel syndrome patients than in controls, and diurnal migrating motor complex intervals were shorter in diarrhea-predominant than in constipation-predominant irritable bowel syndrome. In 11 of 12 inflammatory bowel syndrome patients, episodes of clustered contractions recurring at 0.9-min intervals were noted; these episodes had a mean duration of 46 min and were often associated with transient abdominal pain and discomfort. In both groups of irritable bowel syndrome patients, defecation was significantly (p less than 0.01) prolonged with a greater number of voluntary abdominal contractions (p less than 0.01) than in controls. Prolonged ambulant monitoring of proximal bowel motor activity in subjects who are free to move, eat, and sleep as they choose has, for the first time, clearly defined the striking difference in motility between the sleeping and waking state and shown that abnormalities associated with irritable bowel syndrome are confined to the latter.

Colonic transit in man is slowed by ondansetron (GR38032F), a selective 5-hydroxytryptamine receptor (type 3) antagonist

Ondansetron (GR38032F) is a selective antagonist of 5-hydroxytryptamine (5-HT) type 3 receptors. This randomized, double-blind, cross-over study was undertaken to evaluate and compare the effect of ondansetron with placebo on gastrointestinal transit in 10 healthy male volunteers. There were no significant differences between the effects of placebo and ondansetron on gastric emptying or mouth-to-caecum transit time. However, significant differences in mean whole-gut transit time were observed, that is 54.8 h with ondansetron and 32.1 h with placebo. Therefore, 5-HT3 receptors may be involved in the regulation of colonic transit and ondansetron may prove useful as an anti-diarrhoeal agent.

Effect of octreotide on mouth-to-caecum transit time in healthy subjects and in the irritable bowel syndrome

The effect of a single subcutaneous injection of octreotide (50 micrograms) on mouth-to-caecum transit time was determined in patients with the irritable bowel syndrome who complained of bowel frequency, and in healthy volunteers. The assessment of mouth-to-caecum transit time was performed by monitoring breath hydrogen concentration and noting a sustained 10 p.p.m. rise after ingestion of lactulose 40 ml. Measurements were performed fasting, and on a separate day, after a standard breakfast which included 40 ml lactulose. The studies were performed double-blind in a pre-determined random order. Octreotide prolonged mouth-to-caecum transit time in irritable bowel syndrome patients and healthy subjects by factors of 2.4 and 2.6 after lactulose when fasting, respectively, and by factors of 2.8 and 2.6 after the breakfast which contained lactulose. The upper gastrointestinal transit rate was similar in irritable bowel syndrome patients and healthy controls.