The Effect of Dietary Intervention on Irritable Bowel Syndrome: A Systematic Review.

OBJECTIVES: Elimination diets have been used for many years to treat irritable bowel syndrome (IBS). These approaches had fallen out of favor until a recent resurgence, which was based on new randomized controlled trial (RCT) data that suggested it might be effective. The evidence for the efficacy of dietary therapies has not been evaluated systematically. We have therefore conducted a systematic review to examine this issue. METHODS: MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched up to December 2013. Trials recruiting adults with IBS, which compared any form of dietary restriction or addition of an offending food group in patients already on a restricted diet vs. placebo, control therapy, or "usual management", were eligible. Dichotomous symptom data were pooled to obtain a relative risk of remaining symptomatic after therapy as well as the number needed to treat with a 95% confidence interval. RESULTS: We identified 17 RCTs involving 1,568 IBS patients that assessed elimination diets. Only three RCTs involving 230 patients met our eligibility criteria, all of which evaluated different approaches, and thus a meta-analysis could not be conducted. CONCLUSIONS: More evidence is needed before generally recommending elimination diets for IBS patients.

Efficacy of prebiotics, probiotics, and synbiotics in irritable bowel syndrome and chronic idiopathic constipation: systematic review and meta-analysis.

OBJECTIVES: Irritable bowel syndrome (IBS) and chronic idiopathic constipation (CIC) are functional bowel disorders. Evidence suggests that disturbance in the gastrointestinal microbiota may be implicated in both conditions. We performed a systematic review and meta-analysis to examine the efficacy of prebiotics, probiotics, and synbiotics in IBS and CIC. METHODS: MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to December 2013). Randomized controlled trials (RCTs) recruiting adults with IBS or CIC, which compared prebiotics, probiotics, or synbiotics with placebo or no therapy, were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). Continuous data were pooled using a standardized or weighted mean difference with a 95% CI. RESULTS: The search strategy identified 3,216 citations. Forty-three RCTs were eligible for inclusion. The RR of IBS symptoms persisting with probiotics vs. placebo was 0.79 (95% CI 0.70-0.89). Probiotics had beneficial effects on global IBS, abdominal pain, bloating, and flatulence scores. Data for prebiotics and synbiotics in IBS were sparse. Probiotics appeared to have beneficial effects in CIC (mean increase in number of stools per week=1.49; 95% CI=1.02-1.96), but there were only two RCTs. Synbiotics also appeared beneficial (RR of failure to respond to therapy=0.78; 95% CI 0.67-0.92). Again, trials for prebiotics were few in number, and no definite conclusions could be drawn. CONCLUSIONS: Probiotics are effective treatments for IBS, although which individual species and strains are the most beneficial remains unclear. Further evidence is required before the role of prebiotics or synbiotics in IBS is known. The efficacy of all three therapies in CIC is also uncertain.

The effect of fiber supplementation on irritable bowel syndrome: a systematic review and meta-analysis.

OBJECTIVES: Fiber has been used for many years to treat irritable bowel syndrome (IBS). This approach had fallen out of favor until a recent resurgence, which was based on new randomized controlled trial (RCT) data that suggested it might be effective. We have previously conducted a systematic review of fiber in IBS, but new RCT data for fiber therapy necessitate a new analysis; thus, we have conducted a systematic review of this intervention. METHODS: MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched up to December 2013. Trials recruiting adults with IBS, which compared fiber supplements with placebo, control therapy, or "usual management", were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy as well as number needed to treat (NNT) with a 95% confidence interval (CI). RESULTS: We identified 14 RCTs involving 906 patients that had evaluated fiber in IBS. There was a significant benefit of fiber in IBS (RR=0.86; 95% CI 0.80-0.94 with an NNT=10; 95% CI=6-33). There was no significant heterogeneity between results (I(2)=0%, Cochran Q=13.85 (d.f.=14), P=0.46). The benefit was only seen in RCTs on soluble fiber (RR=0.83; 95% CI 0.73-0.94 with an NNT=7; 95% CI 4-25) with no effect seen with bran (RR=0.90; 95% CI 0.79-1.03). CONCLUSIONS: Soluble fiber is effective in treating IBS. Bran did not appear to be of benefit, although we did not uncover any evidence of harm from this intervention, as others have speculated from uncontrolled data.

Effect of antidepressants and psychological therapies, including hypnotherapy, in irritable bowel syndrome: systematic review and meta-analysis.

OBJECTIVES: Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder. Evidence relating to the treatment of this condition with antidepressants and psychological therapies continues to accumulate. METHODS: We performed an updated systematic review and meta-analysis of randomized controlled trials (RCTs). MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched (up to December 2013). Trials recruiting adults with IBS, which compared antidepressants with placebo, or psychological therapies with control therapy or "usual management," were eligible. Dichotomous symptom data were pooled to obtain a relative risk (RR) of remaining symptomatic after therapy, with a 95% confidence interval (CI). RESULTS: The search strategy identified 3,788 citations. Forty-eight RCTs were eligible for inclusion: thirty-one compared psychological therapies with control therapy or "usual management," sixteen compared antidepressants with placebo, and one compared both psychological therapy and antidepressants with placebo. Ten of the trials of psychological therapies, and four of the RCTs of antidepressants, had been published since our previous meta-analysis. The RR of IBS symptom not improving with antidepressants vs. placebo was 0.67 (95% CI=0.58-0.77), with similar treatment effects for both tricyclic antidepressants and selective serotonin reuptake inhibitors. The RR of symptoms not improving with psychological therapies was 0.68 (95% CI=0.61-0.76). Cognitive behavioral therapy, hypnotherapy, multicomponent psychological therapy, and dynamic psychotherapy were all beneficial. CONCLUSIONS: Antidepressants and some psychological therapies are effective treatments for IBS. Despite the considerable number of studies published in the intervening 5 years since we last examined this issue, the overall summary estimates of treatment effect have remained remarkably stable.

Successful gastric volvulus reduction and gastropexy using a dual endoscope technique.

Gastric volvulus is a life threatening condition characterized by an abnormal rotation of the stomach around an axis. Although the first line treatment of this disorder is surgical, we report here a case of gastric volvulus that was endoscopically managed using a novel strategy. An 83-year-old female with a history of pancreatic cancer status postpylorus-preserving Whipple procedure presented with a cecal volvulus requiring right hemicolectomy. Postoperative imaging included a CT scan and upper GI series that showed a gastric volvulus with the antrum located above the diaphragm. An upper endoscopy was advanced through the pylorus into the duodenum and left in this position to keep the stomach under the diaphragm. A second pediatric endoscope was advanced alongside and used to complete percutaneous endoscopic gastrostomy (PEG) placement for anterior gastropexy. The patient's volvulus resolved and there were no complications. From our review of the literature, the dual endoscopic technique employed here has not been previously described. Patients who are poor surgical candidates or those who do not require emergent surgery can possibly benefit the most from similar minimally invasive endoscopic procedures as described here.

Recorded lower esophageal pressures as a function of electronic sleeve placement and location of gastric pressure measurement in patients with hiatal hernia.

BACKGROUND/AIMS: In high-resolution manometry lower esophageal sphincter pressure (LESP) is measured relative to intragastric pressure, however Gastric Marker™ (GM) location used to determine resting LESP is not well established with hiatal hernia (HH). We test the hypothesis that measured resting LESP varies with HH based on GM location. METHODS: Subjects with HH ≥ 2 cm were included. The eSleeve™ was adjusted to span only the LES, excluding the crural diaphragm (CD). Resting LESP was determined by placing the GM below and above the CD (in the position yielding the highest resting LESP). Resting pressure across the lower esophageal sphincter (LES) to CD and pressure in the HH relative to subdiaphragmatic intragastric pressure were also measured. RESULTS: HH ≥ 2 cm was present in 98 patients (mean length 2.7 cm). LESP decreased when GM was moved from below the CD into the HH: respiratory minimum LESP 7.5 ± 1.1 to 3.6 ± 0.9 mmHg; P < 0.001, mean LESP 17.7 ± 1.3 to 13.7 ± 1.1 mmHg; P < 0.001. When the eSleeve encompassed the LES and CD, the respiratory minimum pressure was 12.2 ± 0.9 mmHg and mean pressure was 23.9 ± 1.0 mmHg pressure (P < 0.001 for both). Pressure in the hernia pouch was greater than intragastric pressure: respiratory minimum 3.0 ± 0.7 mmHg and mean 9.0 ± 0.8 mmHg (P < 0.001 for both). pH studies showed a trend toward an association between abnormal distal esophagus acid exposure and lower resting LESP. CONCLUSIONS: GM placement in the HH produces lower resting LESPs. This may provide a more physiologic representation of LESP in HH.

Severity of dyspeptic symptoms correlates with delayed and early variables of gastric emptying.

BACKGROUND: A simplified report of gastric retention values at select times is now recommended for scintigraphic gastric emptying test (GET). AIMS: The purpose of this study was to assess correlation between severity of gastroparetic symptoms and all variables of GET, compared to select variables in clinical use. METHODS: This was a prospective study of patients referred for scintigraphic GET. The Gastroparesis Cardinal Symptom Index questionnaire was obtained prior to the scintigraphy. Variables determined were lag time, half emptying time (T1/2), retention at 30 min, 1, 2 and 4 h. Statistical analysis was by Spearman rank correlation and Wilcoxon rank test with a significance set at p ≤ 0.05. RESULTS: Seven hundred seventeen patients had GET from 03/09 to 03/11. Results are from 325 patients who did not take medications known to affect GET were analyzed (64.9 % females, mean age 47 ± 18.9 years, 21.8 % diabetics, 78.2 % non-diabetic, of which 7.6 % were post-surgical, primarily post-fundoplication). Combined gastric retention at 2 and 4 h detected delayed GET in 83.5 % non-diabetics and 76.6 % of diabetics. Rapid GET was present in 11 % of patients at 30 min and 4 % at 1 h. Significant positive correlation was observed between nausea, vomiting, loss of appetite and variables of GET, but not with the half-time of emptying (T1/2). Bloating negatively correlated with retention at 2 h. There was no association between duration of symptoms and GET variables. CONCLUSIONS: Gastroparetic symptoms correlate with different retention times of GET, but not with T1/2. However, symptoms poorly distinguish between categories of gastroparesis or status of gastric emptying. Delayed GE is best detected by 2 and 4 h retention times, while 30 min and 1 h retention times detect rapid GE.

Smoothelin expression in the gastrointestinal tract: implication in colonic inertia.

Colonic inertia is a frustrating motility disorder to patients, clinicians, and pathologists. The pathogenesis is largely unknown. The aims of this study were to: (1) characterize the expression of smoothelin, a novel smooth muscle-specific contractile protein expressed only by terminally differentiated smooth muscle cells, in the normal gastrointestinal (GI) tract; and (2) determine whether smoothelin is aberrantly expressed in patients with colonic inertia. A total of 57 resections of the normal GI tract (distal esophagus to left colon) were obtained from patients without GI motor dysfunction. Sixty-one colon resections were obtained from patients with a clinical diagnosis of colonic inertia. Smoothelin immunostaining was conducted on full-thickness tissue sections. In the nondysmotile controls, strong and diffuse cytoplasmic staining for smoothelin was observed in both the inner circular and outer longitudinal layers of the muscularis propria (MP) throughout the entire GI tract. The muscularis mucosae (MM) and muscular vessel walls were either completely negative or only patchily and weakly stained. The 1 exception to this pattern was observed in the distal esophagus, in which the MM was also diffusely and strongly stained. In cases with colonic inertia, a moderate to marked reduction of smoothelin immunoreactivity was observed in 15 of 61 (24.6%) colon resections, selectively seen in the outer layer of the MP. The data demonstrate that smoothelin is differentially expressed in the MP and MM of the normal GI tract and suggest that defective smoothelin expression may play a role in the pathogenesis of colonic inertia in a subset of patients.

Correlation between serum serotonin and endoscopy inflammation scores in patients with ileal pouches.

BACKGROUND: Inflammatory and functional complications are common in patients with inflammatory bowel disease (IBD) after restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA). The pathogenesis of these complications remains poorly understood, and there is discrepancy between the clinical symptoms and objective endoscopic inflammation scores in these patients. While serum serotonin level has been reported to be associated with symptoms of irritable bowel syndrome, its association with ileal pouch disorders has not been studied. AIM: To investigate the association between serum serotonin level and symptoms and endoscopic inflammation in patients with IPAA. METHODS: A total of 185 consecutive eligible IPAA patients who presented to a specialized Pouchitis Clinic from Jan 2009 to May 2009 were prospectively recruited. Patients were divided into 4 groups: normal pouch, irritable pouch syndrome (IPS), inflammatory pouch disorders (Crohn's disease, acute and chronic pouchitis, and cuffitis), and surgical complications. Serum serotonin level was measured and analyzed for correlation with clinical and endoscopic inflammation scores. RESULTS: Demographic and clinical variables were evaluated, including age, gender, smoking history, duration of UC, duration of the pouch, and disease category of the pouch. The median fasting serum serotonin level was comparable among the 4 groups: 94.0 ng/ml (interquartile range [IQR], 70.0, 128.1), 89.2 ng/ml (IQR 54.2, 155.9), 90.3 ng/ml (IQR 49.7, 164.1), 77.9 ng/ml (IQR 54.7, 129.0), for normal pouch, irritable pouch, inflammatory pouch disorders, and surgical complication groups, respectively (p=0.91). A significant association between serum serotonin level and the Pouchitis Disease Activity Index (PDAI) endoscopy subscore of the pouch (odds ratio [OR]=1.9, 95% confidence interval [CI]: 1.2, 2.9, p<0.05) and total PDAI endoscopy score (OR=1.8; 95% CI: 1.2, 2.8, p<0.05) in the inflammatory complication group were noted. CONCLUSIONS: Serum serotonin level appears to correlate with the PDAI endoscopy subscores and total PDAI score in patients with inflammatory complications suggesting that the hormone may be involved in mechanisms of mucosal inflammation. These findings may promote future treatment strategies for patients with pouch inflammation.

Gastric electrical stimulation for gastroparesis.

Gastric electrical stimulation (GES) for gastroparesis has been in use for more than a decade. Multiple publications, consisting almost entirely of open label single center studies, reported a beneficial effect on symptoms, quality of life and nutritional status. Some predictors of better response to GES have been lately identified, primarily diabetic etiology and nausea and vomiting as the predominant symptoms. However, individual response to GES remains difficult to predict. The mechanism of action of GES remains poorly understood. Stimulation parameters approved in clinical practice do not regulate gastric slow wave activity and have inconsistent effect on gastric emptying. Despite such limitations, gastric electrical stimulation remains a helpful intervention in some patients with severe gastroparesis who fail to respond to medical therapy.

Apple sauce improves detection of esophageal motor dysfunction during high-resolution manometry evaluation of dysphagia.

BACKGROUND: Esophageal manometry utilizes water swallows to evaluate esophageal motor abnormalities in patients with dysphagia, chest pain, or reflux symptoms. Although manometry is the gold standard for evaluation of these symptoms, patients with dysphagia often have normal results in manometry studies. AIM: The objective of this work was to test the hypothesis that challenging the esophagus with viscous apple sauce boluses uncovers motor abnormalities in patients with dysphagia not seen when using water swallows. METHODS: High-resolution esophageal manometry was performed using ten water swallows followed by ten apple sauce swallows in consecutive subjects presenting with dysphagia. Subjects with grossly abnormal water swallow evaluations were excluded. Each swallow was categorized as normal, hypotensive (distal isobaric contour plots of < 30 mmHg over >5 cm), or simultaneous (distal esophageal velocity ≥ 8.0 cm/s). Ineffective esophageal motility (IEM) was defined as ≥ 30% hypotensive swallows, and pressurization was defined as ≥ 20% simultaneous pressure waves. RESULTS: Data from 41 subjects was evaluated. Overall, 96.3% of water swallows were normal, 2.9% hypotensive, and 0.7% simultaneous. Only 70.3% of viscous swallows were normal; 16.7% were hypotensive and 13.0% were simultaneous (P < 0.001 all groups). Seven (17.1%) met criteria for IEM, and pressurization with viscous swallows was observed for nine (22.0%). Fourteen subjects (34.1%) had abnormal results from viscous studies. The presence of any abnormal water swallows was predictive of abnormal viscous swallows (OR = 9.00, CI = 2.15-80.0), although the presence of hypotensive or simultaneous water swallows was not associated with IEM (OR = 0.63, CI = 0.16-2.17) or pressurization (OR = 7.00, CI = 0.90-315.4) with viscous apple sauce. CONCLUSIONS: Apple sauce challenge increased identification of classifiable motor disorders in patients with dysphagia and may be preferred to alternative bolus materials.

Irritable pouch syndrome is characterized by visceral hypersensitivity.

BACKGROUND: Irritable pouch syndrome (IPS) is a functional disorder in patients with ileal pouch-anal anastomosis (IPAA), which presents with symptoms in the absence of structural abnormalities of the pouch. Thus, it resembles other functional disorders, such as irritable bowel syndrome characterized by visceral hypersensitivity in the presence of normal rectal biomechanics. The aim was to assess pouch biomechanics and perception of balloon distension in different groups of subjects with IPAA and to correlate the findings with clinical features. METHODS: Pouch tone, compliance, and sensation to balloon distension were measured in 18 patients with IPS, 11 patients with active pouch inflammation (pouchitis or Crohn's disease of the pouch), and 12 asymptomatic subjects with normal pouches. All patients were recruited from a subspecialty Pouchitis Clinic. RESULTS: Scores of sensation of gas, urge to defecate, and pain measured by visual analog scales at various distension pressures were significantly higher in IPS than pouchitis and normal pouch patients. Pouch tone was comparable among the groups and compliance was reduced in the pouchitis group. The visual analog scale showed a trend of correlation with the Pouchitis Disease Activity Index symptom scores in IPS. CONCLUSIONS: IPS, like other gut functional disorders, is characterized by visceral hypersensitivity, with normal pouch biomechanics.

Concurrent findings of achalasia and duodenal duplication in a Down syndrome patient.

The association between Down syndrome and gastrointestinal anomalies such as duodenal and esophageal atresia, tracheoesophageal fistulas, and Hirschsprung's disease is well documented. More recently, an association between Down syndrome and achalasia was reported. In this report, we describe a 48-year-old woman with a history of Down syndrome who presented with dysphagia. Work-up of the dysphagia showed not only achalasia but also a duodenal duplication. To our knowledge, there have been no reports of Down syndrome associated with duodenal duplication. Whether this finding is simply a coincidence or whether duodenal duplication is associated with Down syndrome will need to be determined with future studies.

The effect of eating on lower esophageal sphincter electrical activity.

Electrical activity of the lower esophageal sphincter (LES) has been recorded mainly in vitro and in anesthetized animals. Swallowing produces relaxation of the LES, followed by its contraction. These changes should be associated with changes in LES electrical activity. To determine whether changes in LES electrical activity can be used to recognize the beginning of a meal, four dogs were implanted with two electrodes in the longitudinal axis of the LES. The electrodes were connected to an implantable device for recording of electrical activity. After recovery, dogs underwent two experiments: 1) combined recordings of LES electrical activity and esophageal manometry to test the effect of dry swallows, water, and solid food swallows on LES electrical activity and 2) telemetric recording of LES electrical activity during a standard meal. All amplitudes were in mV, means+/-SD, ANOVA, P<0.05. In experiment 1, an increase in the amplitude of LES electrical activity was associated with the substance being swallowed, i.e., at rest: 0.31+/-0.06; dry swallows: 0.6+/-.0.1; water: 0.67+/-0.12; solid food: 1.06+/-0.17, P<0.001. In experiment 2, there was a pronounced and characteristic increase in amplitude of LES electrical activity during feeding, 0.26+/-0.1; during fasting, 0.99+/-0.23; while eating, 0.31+/-0.1 postprandial, P<0.001. In conclusion, the beginning and duration of a meal are identified by distinct, easily recognizable changes in the amplitude of LES electrical activity. These changes depend on the type of the substance being swallowed and are most prominent with solid food. Changes in LES electrical activity can potentially be used for automatic eating detection.

Gastric electrical stimulation with the TANTALUS System in obese type 2 diabetes patients: effect on weight and glycemic control.

BACKGROUND: The TANTALUS System is an investigational device that consists of an implantable pulse generator connected to gastric electrodes. The system is designed to automatically detect when eating starts and only then deliver sessions of gastric electrical stimulation (GES) with electrical pulses that are synchronized to the intrinsic antral slow waves. We report the effect of this type of GES on weight loss and glucose control in overweight/obese subjects with type 2 diabetes mellitus (T2DM). This study was conducted under a Food and Drug Administration/Institutional Review Board-approved investigational device exemption. METHOD: Fourteen obese T2DM subjects on oral antidiabetes medication were enrolled and implanted laparoscopically with the TANTALUS System (body mass index 39 +/- 1 kg/m(2), hemoglobin A1c [HbA1c] 8.5 +/- 0.2%).Gastric electrical stimulation was initiated four weeks after implantation. Weight, HbA1c, fasting blood glucose, blood pressure, and lipid levels were assessed during the study period. RESULTS: Eleven subjects reached the 6-month treatment period endpoint. Gastric electrical stimulation was well tolerated by all subjects. In those patients completing 6 months of therapy, HbA1c was reduced significantly from 8.5 +/- 0.7% to 7.6 +/- 1%, p < .01. Weight was also significantly reduced from 107.7 +/- 21.1 to 102.4 +/- 20.5 kg, p < .01. The improvement in glucose control did not correlate with weight loss (R(2) = 0.05, p = .44). A significant improvement was noted in blood pressure, triglycerides, and cholesterol (low-density lipoprotein only). CONCLUSIONS: Short-term therapy with the TANTALUS System improves glucose control, induces weight loss, and improves blood pressure and lipids in obese T2DM subjects on oral antidiabetes therapy.

Effect of electrical stimulation of the LES on LES pressure in a canine model.

Gastric electrical stimulation modulates lower esophageal sphincter pressure (LESP). High-frequency neural stimulation (NES) can induce gut smooth muscle contractions. To determine whether lower esophageal sphincter (LES) electrical stimulation (ES) can affect LESP, bipolar electrodes were implanted in the LES of four dogs. Esophageal manometry during sham or ES was performed randomly on separate days. Four stimuli were used: 1) low-frequency: 350-ms pulses at 6 cycles/min; 2) high-frequency-1: 1-ms pulses at 50 Hz; 3) high-frequency-2: 1-ms pulses at 20 Hz; and 4) NES: 20-ms bipolar pulses at 50 Hz. Recordings were obtained postprandially. Tests consisted of three 20-min periods: baseline, stimulation/sham, and poststimulation. The effect of NES was tested under anesthesia and following IV administration of l-NAME and atropine. Area under the curve (AUC) and LESP were compared among the three periods, by ANOVA and t-test, P < 0.05. Data are shown as means +/- SD. We found that low-frequency stimulation caused a sustained increase in LESP: 32.1 +/- 12.9 (prestimulation) vs. 43.2 +/- 18.0 (stimulation) vs. 50.1 +/- 23.8 (poststimulation), P < 0.05. AUC significantly increased during and after stimulation. There were no significant changes with other types of ES. With NES, LESP initially rose and then decreased below baseline (LES relaxation). During NES, N(G)-nitro-l-arginine methyl ester increased both resting LESP and the initial rise in LESP and markedly diminished the relaxation. Atropine lowered resting LESP and abolished the initial rise in LESP. In conclusion, low frequency ES of the LES increases LESP in conscious dogs. NES has dual effect on LESP: an initial stimulation, cholinergically mediated, followed by relaxation mediated by nitric oxide.

Association between gastric electromechanical activity and satiation in dogs.

OBJECTIVE: The objective of this study was to validate the use of impedance for measurement of antral contractions and to determine the relationship between food-induced changes in gastric motility and satiation. RESEARCH METHODS AND PROCEDURES: In Experiment 1, three dogs were implanted with an antral strain gauge and bipolar electrodes for measurement of local tissue impedance. Impedance and strain gauge recordings were obtained simultaneously during antral contractions to correlate impedance changes with contractile events. In Experiment 2, seven dogs were implanted with two pairs of gastric electrodes for simultaneous recording of slow wave activity and impedance. The changes in the rate of slow waves and of antral contractions assessed by impedance during food intake were characterized. RESULTS: Variations in strain gauge amplitude were highly correlated with changes in antral impedance (R2: 0.70 to 0.82, p < 0.05). In Experiment 2, slow wave rate was significantly reduced after food intake and reached a nadir at satiation (5.0 +/- 0.3 vs. 3.8 +/- 0.5 events/min, p < 0.001). Likewise, the amplitude of antral contractions assessed by variations in impedance was significantly increased after food intake, peaking at satiation (5.3 +/- 1.4 vs. 12.2 +/- 4.3 Ohms, p < 0.01). DISCUSSION: Measurement of impedance is a reliable tool for assessing gastric contractility. Food ingestion significantly reduces slow wave rate and enhances antral contractions. Peak changes in these two variables occur at the time of satiation. Electrical measurements of both slow waves and impedance may be used to estimate gastric motility and satiation.

The TANTALUS system for obesity: effect on gastric emptying of solids and ghrelin plasma levels.

BACKGROUND: Gastric electrical stimulation (GES), using the implantable TANTALUS System, is being explored as a treatment for obesity. The system delivers nonstimulatory electrical signals synchronized with gastric slow waves, resulting in stronger contractions. We hypothesized that this GES may enhance gastric emptying and as a result affect plasma ghrelin and insulin homeostasis. The aim was to test the effect of GES on gastric emptying of solids and on ghrelin and insulin blood levels in obese subjects. METHODS: The system consists of 3 pairs of gastric electrodes connected to an implantable pulse generator. Gastric emptying test (GE) of solids was performed twice, on separate days, a few weeks after implantation, before and after initiation of stimulation. Blood samples for ghrelin and insulin were taken at baseline and at 15, 30, 60 and 120 min after the test meal. RESULTS: There were 11 females, 1 male, mean age 39.1 +/- 8.9 years, mean BMI 41.6 +/- 3.4. Data is available from 11 subjects; GE was normal in 9 subjects and accelerated in 2 subjects. GES significantly accelerated GE compared to control: percent retention at 2 hours 18.7 +/- 12.2 vs 31.9 +/- 16.4, respectively (P < 0.01). Overall, there was no significant change in ghrelin or insulin profile after food intake. Ghrelin levels fell significantly at 60 min compared to baseline during stimulation (P = 0.014) and control (P = 0.046). CONCLUSION: GES results in a significant acceleration of gastric emptying of solids in obese subjects. GES did not have a significant effect on postprandial ghrelin levels when compared to control.

Esophageal manometry: assessment of interpreter consistency.

BACKGROUND AND AIMS: Manometry is used widely in the evaluation of esophageal disorders. Our aim was to assess the intra- and interobserver reliability of esophageal manometry and identify potential causes for diagnostic variability. METHODS: Seventy-two esophageal manometry tracings were selected randomly from archives. Eight interpreters randomly and blindly evaluated tracings. Interpreters were divided into 3 groups: highly experienced (N = 3), moderately experienced (N = 3), and inexperienced (N = 2). Each tracing was examined for abnormalities involving the lower-esophageal sphincter (LES) and esophageal body. Interpreters rendered a single diagnosis from a list of 7 manometric diagnoses: normal, nutcracker, hypertensive LES, hypotensive LES, diffuse esophageal spasm (DES), nonspecific/ineffective esophageal motility (IEM), and achalasia. Intra- and interobserver agreements were determined and reasons for varied diagnoses were investigated. RESULTS: Overall intraobserver agreement was good (kappa = .63, P < .0001). There was no difference ( P = .9) between the highly and midexperienced interpreters (kappa = .61 and .65, respectively). Interobserver agreement for the diagnosis of achalasia and normal motility was good (kappa = .65 and .56, respectively). However, other manometric diagnoses yielded only fair interobserver agreement (kappa = .27). DES, nonspecific/ineffective esophageal motility (IEM), and hypo- and hypertensive LES diagnoses showed the least agreement. Poor adherence to established manometric criteria, misinterpretation of intrabolus pressure, and technical inadequacy were the most common sources of inconsistency in interpretations. CONCLUSIONS: Manometric diagnoses of conditions other than normal or achalasia are variable and have poor interobserver variability. Given their uncertain clinical implications, we must either redefine them or eliminate them from practice.