Lower postprandial gastric volume response in diabetic patients with vagal neuropathy

Poor relaxation in the stomach after a meal may contribute to disturbed gastric emptying and abdominal discomfort in patients with diabetes mellitus. In this study we aimed to compare barostat-recorded postprandial volume responses in these patients to those in healthy controls, and to study the relationship between the proximal volume responses, antral filling and vagal neuropathy.
We compared 14 consecutively recruited patients with type 1 diabetes mellitus (DM) to 18 healthy controls (HC) with respect to meal-induced gastric volume response assessed by a barostat, antral area recorded by ultrasound, and vagal tone assessed by respiratory sinus arrhythmia (RSA).
Meal-induced volume repsponse of the proximal stomach (area under time–volume curve 0–30 min) was significantly (P = 0.04) lower in DM than in HC, 49.4 min.mL ± 60.7 vs. 114.9 min.mL ± 100.8. Antral area was significantly larger in DM than in HC, both fasting (4.3 cm² ± 1.9 vs. 3.0 cm² ± 0.9) and 10 min after ingestion of meat soup (11.8 cm² ± 3.4 vs. 8.8 cm² ± 2.9), P = 0.03 and P = 0.02, respectively. Vagal tone was significantly (P = 0.01) lower in DM than in HC, 3.7 beats min⁻¹ ± 2.3 vs. 6.1 beats min⁻¹ ± 2.2. No significant correlation was observed between the proximal volume responses and antral widening. Maximal gastric volume response correlated significantly with vagal tone (r = 0.77, P = 0.002). Conclusions: patients with diabetes mellitus type 1 have impaired meal-induced volume response, possibly as a consequence of reduced vagal tone.     

Prolonged duodenal acid perfusion and dyspeptic symptom occurrence in healthy volunteers

Abstract  The pathophysiology of functional dyspepsia (FD) is unknown and several mechanisms associated with specific symptom patterns have been recently proposed. Increased duodenal acid exposure has been supposed to be associated with nausea, but recently an increase of severity of several dyspeptic symptoms was noted in a subset of dyspeptic patients. As its pathogenetic role is still unclear, we evaluated an involvement of duodenal acid exposure in symptom generation by inducing a hyperacidity status of the duodenum. Twelve young adult healthy volunteers in a randomized, double-blind protocol, underwent duodenal acid (0.2 N, 5 mL min⁻¹) or saline perfusion, antropyloroduodenal manometry and duodenal pH monitoring both during fasting and postprandially. Every 15 min, severity of discomfort, fullness, bloating, belching, nausea, heartburn, epigastric burning, satiety and pain were evaluated by visual analogue scale. During acid perfusion, symptom scores for discomfort, bloating, nausea, epigastric burning were significantly higher ( P  < 0.01) compared to saline. Postprandial antral motility index was lower (2.96 ± 1.8 vs 3.62 ± 1.8, P  = 0.01) and jejunal motility index higher (4.87 ± 1.0 vs 4.37 ± 1.4, P  = 0.01) during acid perfusion. Occurrence and duration of phases III of the migrating motor complex showed no difference. Duodenal acid perfusion causes a sensitization to dyspeptic symptoms and induces antral hypomotility and jejunal hypercontractility. Through these mechanisms, increased duodenal acid exposure may play a role in the pathophysiology of FD symptoms.     

Postprandial gastric antral contractions in patients with gastro-oesophageal reflux disease: a scintigraphic study

Abstract  Disturbed gastric contractility has been found in manometric studies in patients with gastro-oesophageal reflux disease (GORD), but the pathophysiological role of this abnormality is unclear. We aimed at assessing postprandial gastric antral contractions and its relationships with gastric emptying and gastro-oesophageal reflux in GORD patients. Fasted GORD patients ( n  = 13) and healthy volunteers ( n  = 13) ingested a liquid meal labelled with 72 MBq of ^99mTechnetium-phytate. Gastric images were acquired every 10 min for 2 h, for measuring gastric emptying half time. Dynamic antral scintigraphy (one frame per second), performed for 4 min at 30-min intervals, allowed estimation of both mean dominant frequency and amplitude of antral contractions. In GORD patients ( n  = 10), acidic reflux episodes occurring 2 h after the ingestion of the same test meal were determined by ambulatory 24-h oesophageal pH monitoring. Gastric emptying was similar in GORD patients and controls (median; range: 82 min; 58–126 vs 80 min; 44–122 min; P  = 0.38). Frequency of antral contractions was also similar in both groups (3.1 cpm; 2.8–3.6 vs 3.2 cpm; 2.4–3.8 cpm; P  = 0.15). In GORD patients, amplitude of antral contractions was significantly higher than in controls (32.7%; 17–44% vs 23.3%; 16–43%; P  = 0.01), and correlated positively with gastric emptying time ( R _s = 0.58; P  = 0.03) and inversely with the number of reflux episodes ( R _s = −0.68; P  = 0.02). Increased amplitude of postprandial gastric antral contractions in GORD may comprise a compensatory mechanism against delayed gastric emptying and a defensive factor against acidic gastro-oesophageal reflux.     

Sham feeding disrupts phase III of the duodenal migrating motor complex in humans

The role of the vagus nerve in the control of the intestinal migrating motor complex (MMC) is unclear. This study aimed to evaluate the effect of physiological vagal stimulation with sham feeding on phase III of the MMC. Antroduodenal motility was recorded in six healthy volunteers. The first phase III was used as a control, and sham feeding was performed during the second phase III. The MMC was disrupted within 1.5 ± 0.4 min of sham feeding and its duration was shorter than the control phase III. Phase III propagation was inhibited in all subjects, most of them exhibiting no propagation beyond the third duodenal recording site. During sham feeding, the antrum exhibited transient phasic contractions in five out of six subjects. The duodenal motility index recorded for up to 30 min after the onset of the sham feeding was unchanged in five out of six subjects. We conclude that sham feeding consistently interrupted phase III of the duodenal MMC and induced antral contractions, but failed to provoke significant motor events in the duodenum.     

Does the nutrient drink test accurately predict postprandial gastric volume in health and community dyspepsia?

Abstract  Nutrient drink tests have been proposed as a surrogate for measurement of gastric accommodation. To study the relationship of maximum tolerated volume (MTV) during nutrient drink test and gastric volumes measured by single-photon emission computed tomography (SPECT) in healthy controls and functional dyspepsia (FD) patients. We reviewed data from 85 healthy controls and 35 FD residents of south-eastern Minnesota. All underwent standardized nutrient drink and SPECT studies between August 2000 and June 2003. To test for associations between nutrient drink test and SPECT gastric volumes, we used multiple linear regression and partial regression analyses, assigning age, gender, dyspepsia status and postprandial symptoms as covariates in the model. In the combined group (healthy and FD), MTV was weakly associated with fasting gastric volume ( r  = 0.43, P  = 0.0001) and with volume response to feeding ( r  = 0.25, P  = 0.006). In the FD group, associations were similar (fasting r  = 0.53, P  = 0.001; postmeal r  = 0.32, P  = 0.06). After accounting for covariates, MTV only explained 13 and 3% of variations in fasting and postprandial volumes measured by SPECT. MTV during the nutrient drink test does not accurately reflect gastric volume measurements by SPECT in healthy controls and a sample of people in the community with FD.     

Delayed gastric emptying rates and impaired antral motility in children fulfilling Rome III criteria for functional abdominal pain

Background Gastric sensorymotor dysfunctions have been implicated in the pathophysiology of some functional gastrointestinal disorders, such as functional dyspepsia and irritable bowel syndrome. Therefore, we hypothesized that abnormal gastric emptying and impaired antral motility are possible underlying mechanisms of symptoms in children with functional abdominal pain (FAP). Methods Hundred and two children [37 (36.3%) males, 4–14 years, mean 7.8 years, SD 2.7 years] fulfilling Rome III criteria for FAP were recruited for this study. An age and sex compatible group of healthy children (n = 20) were selected as controls [8 (40%) males, 4–14 years, mean 8.4 years, SD 3.0 years]. Liquid gastric emptying rate (GER) and antral motility parameters (amplitude of antral contractions, frequency of antral contractions and antral motility index) were assessed using a previously reported ultrasound method. Key Results Average GER (42.1% vs 66.2% in controls), amplitude of antral contractions (56.5% vs 89%), frequency of contractions per 3 min (8.5 vs 9.3), and antral motility index (4.9 vs 8.3) were significantly lower in patients with FAP compared with controls (P < 0.01). Fasting antral area was higher in patients (1.4 vs 0.6, P < 0.0001). GER negatively correlated with the scores obtained for severity of abdominal pain (r = ?0.29, P = 0.004). Conclusions & Inferences Gastric emptying rate and antral motility parameters were significantly impaired in patients with FAP and GER negatively correlated with symptom severity. These findings highlight the possible role of gastrointestinal motility abnormalities in the pathophysiology of childhood FAP.     

A dose-ranging, placebo-controlled, pilot trial of Acotiamide in patients with functional dyspepsia

Abstract  Impaired gastric accommodation, hypersensitivity to distension and delayed gastric emptying are major pathophysiological mechanisms in functional dyspepsia (FD). Acotiamide (Z-338) was well-tolerated in healthy volunteers. To determine the effect of three doses of Acotiamide on major pathophysiological mechanisms, symptoms, quality of life (QOL) and safety in functional dyspeptics. A phase IIa, randomized, double-blind, placebo-controlled study (14, 21 and 28 days, respectively, for run-in, study drug administration and follow-up). Gastric accommodation, sensitivity to distension and gastric emptying were assessed by barostat and ¹³C breath test, symptoms by daily diary cards and QOL by SF-36. A total of 71 patients were enrolled (62 evaluable). There was no effect on gastric emptying and sensitivity to distension. 300 mg was better than placebo for meal accommodation ( P  = 0.024). 100 mg was better than placebo at week 2 for upper abdominal bloating ( P  = 0.001) and overall symptom score ( P  = 0.022), and at week 3 for bloating ( P  = 0.008) and heartburn ( P  = 0.041). 100 mg was also better than placebo for QOL (physical function) ( P  = 0.003). Acotiamide was safe and well-tolerated in patients with FD. The involved mechanism could at least in part depend on an effect on meal-induced accommodation. 100 mg Acotiamide exhibited the potential to improve FD symptoms and QOL. Further studies are indicated.     

Influence of abuse history on gastric sensorimotor function in functional dyspepsia

Abstract  Patients with functional gastrointestinal disorders have elevated rates of sexual or physical abuse, which may be associated with altered rectal sensorimotor function in irritable bowel syndrome. The aim was to study the association between abuse history and gastric sensorimotor function in functional dyspepsia (FD). We studied gastric sensorimotor function with barostat (sensitivity, compliance and accommodation) and gastric emptying test in 233 consecutive FD patients from a tertiary care centre (162 women, mean age 41.6 ± 0.9). Patients filled out self-report questionnaires on history of sexual and physical abuse during childhood or adulthood. Eighty-four patients (out of 198, 42.4%) reported an overall history of abuse [sexual and physical in respectively 30.0% (60/200) and 20.3% (42/207)]. FD patients reporting general as well as severe childhood sexual abuse have significantly lower discomfort thresholds during gastric distension [respectively 10.5 ± 0.4 vs 7.5 ± 1.0 mmHg above minimal distending pressure (MDP), P  = 0.014 and 10.5 ± 0.4 vs 6.6 ± 1.2 mmHg above MDP, P  = 0.007]. The corresponding intra-balloon volume was also significantly lower (respectively 579 ± 21 vs 422 ± 59 mL, P  = 0.013 and 579 ± 19 vs 423 ± 79 mL, P  = 0.033). Gastric accommodation was significantly more pronounced in patients reporting rape during adulthood (91 ± 12 vs 130 ± 40 mL, P  = 0.016). Abuse history was not associated with differences in gastric emptying. A history of abuse is associated with alterations in gastric sensorimotor function in FD. Particularly sexual abuse, rather than physical abuse, may influence gastric sensitivity and motor function.     

Clinical effects of STW 5 (Iberogast®) are not based on acceleration of gastric emptying in patients with functional dyspepsia and gastroparesis

Abstract  STW 5, a herbal extract, is effective for the treatment of symptoms in patients with functional dyspepsia (FD). However, its mode of action is still unclear and a modulation of gastric motility is hypothesized. This multicentre, placebo-controlled double-blind study addressed the question of whether STW 5 accelerates gastric emptying in patients with FD and gastroparesis. One-hundred and three patients diagnosed with FD were randomly assigned to a treatment with either STW 5 or a liquid placebo for 28 days. The primary end point of the study was a change of a validated gastrointestinal symptom (GIS) score under treatment. Additionally, patients underwent a ¹³C octanoic acid breath test for the assessment of the gastric half-emptying time ( t _1/2). Patients with prolonged t _1/2 were diagnosed with gastroparesis and requested to repeat the test at the end of treatment. A change of t _1/2 was defined a secondary study end point. t _1/2 was prolonged in 48.6% of patients in the STW 5 group and in 43.8% of the placebo group. During treatment, t _1/2 increased non-significantly in patients treated with STW 5 (+23 ± 109 min; P  = 0.51) and slightly accelerated among patients in the placebo arm (−26 ± 51 min; P  = 0.77) ( P  = 0.49). The improvement of the GIS ( P  = 0.08) and the proportion of patients with a treatment response ( P  = 0.03) were more pronounced in the STW 5 group. Our findings suggest that the clinical effects of STW 5 in patients with FD and gastroparesis are not directly mediated by an acceleration of gastric emptying. A clear-cut correlation with symptom improvement is still lacking.     

Reproducibility and symptomatic predictors of a slow nutrient drinking test in health and in functional dyspepsia

Abstract  Impaired accommodation to a meal has been recognized as a pathophysiological mechanism in functional dyspepsia (FD). Based on observations in tertiary care patients, the drinking test has been proposed as a non-invasive tool to estimate accommodation. Our aim was to assess the reproducibility of the drinking test and its correlation with demographic, symptomatic and pathophysiological parameters in secondary care FD patients and healthy controls. Thirty-four healthy controls and 78 FD patients completed a drinking test (3 respectively 2 times), a gastric emptying study and an FD symptom questionnaire. Factors influencing maximal volume and gastric emptying were determined, and the reproducibility of the drinking test was investigated. The maximal satiety was reached at a lower volume in patients (489 ± 276 and 503 ± 248 mL for first and second test respectively vs 937 ± 428 and 1048 ± 421 mL, P  < 0.0001). The ingested amount depended on age, sex and baseline FD symptom score. Patients' sex, final satiety score, total score for stomach complaints at screening and total symptom score before test accounted for the total symptom score after the test. The slow nutrient drinking test confirms its possible role as an attractive non-invasive and reproducible tool for the diagnosis of impaired accommodation and for the assessment of treatment responsiveness.     

Gastric motor disturbances in patients with idiopathic rapid gastric emptying

Background The mechanisms of ‘idiopathic’ rapid gastric emptying, which are associated with functional dyspepsia and functional diarrhea, are not understood. Our hypotheses were that increased gastric motility and reduced postprandial gastric accommodation contribute to rapid gastric emptying. Methods Fasting and postprandial (300 kcal nutrient meal) gastric volumes were measured by magnetic resonance imaging (MRI) in 20 healthy people and 17 with functional dyspepsia; seven had normal and 10 had rapid gastric emptying. In 17 healthy people and patients, contractility was analyzed by spectral analysis of a time‐series of gastric cross‐sectional areas. Logistic regression models analyzed whether contractile parameters, fasting volume, and postprandial volume change could discriminate between health and patients with normal or rapid gastric emptying. Key Results While upper gastrointestinal symptoms were comparable, patients with rapid emptying had a higher (P = 0.002) body mass index than normal gastric emptying. MRI visualized propagating contractions at ～3 cpm in healthy people and patients. Compared with controls (0.32 ± 0.04, Mean ± SEM), the amplitude of gastric contractions in the entire stomach was higher (OR 4.1, 95% CI 1.2–14.0) in patients with rapid (0.48 ± 0.06), but not normal gastric emptying (0.20 ± 0.06). Similar differences were observed in the distal stomach. However, the propagation velocity, fasting gastric volume, and the postprandial volume change were not significantly different between patients and controls. Conclusions & Inferences MRI provides a non‐invasive and refined assessment of gastric volumes and contractility in humans. Increased gastric contractility may contribute to rapid gastric emptying in functional dyspepsia.     

Intragastric distribution of a standardized meal in health and functional dyspepsia: correlation with specific symptoms

In functional dyspepsia, abnormal intragastric distribution of a test meal has been identified but has never been correlated to any symptom pattern. The aim of this study was to compare the intragastric distribution of a meal between functional dyspepsia patients and controls, and to correlate distribution with symptom patterns, using scintigraphic gastric emptying studies. In forty patients with functional dyspepsia and 29 healthy volunteers, scintigraphic planar images were obtained immediately after ingestion of a mixed radiolabelled test meal and every 20 min for 2 h. The images of the stomach were divided into proximal and distal compartments. The mean intragastric distribution was similar in patients and controls. Over the whole test, 18 (45%) and 20 (50%) patients had a distal redistribution of the solid and liquid phase of the meal, respectively, while proximal retention of these phases was found in 13 (33%) and 9 (23%) patients. Early satiety was associated with early distal redistribution of the liquid phase and fullness was associated with late proximal retention. This study shows similar intragastric distribution of a test meal in health and functional dyspepsia. Within the patient group, an association between abnormal intragastric distribution patterns and symptom profiles was found, which might be related to different pathophysiological mechanisms.     

Influence of a 5HT1 receptor agonist on gastric accommodation and initial transpyloric flow in healthy subjects

Sumatriptan, a 5HT1 receptor agonist, inhibits antral motor activity, delays gastric emptying and relaxes the gastric fundus. The aim of this study was to characterize the effect of sumatriptan on transpyloric flow and gastric accommodation during and immediately after ingestion of a liquid meal using duplex sonography. Ten healthy subjects were investigated twice on separate days. In random order either sumatriptan 6 mg (Imigran® 0.5 mL) or a placebo were given s.c. 15 min before ingesting 500 mL of a meat soup. The subjects were examined during the 3-min period before ingestion of the liquid meal, the 3-min spent drinking the meal and 10 min postprandially. Sumatriptan caused a significant widening of both the gastric antrum (P=0.02) and the proximal stomach (P=0.01) 10 min postprandially as compared with placebo. It caused no significant differences in time to initial gastric emptying (P=0.2), but significantly delayed commencement of peristaltic-related transpyloric flow (P=0.04). Sumatriptan had no significant effect on mean abdominal symptom scores, but after sumatriptan there was a significant negative correlation between width of postprandial antral area and postprandial nausea and between width of postprandial antral area and postprandial bloating. We therefore conclude that sumatriptan causes a postprandial dilatation of both the distal and the proximal stomach with no change in dyspeptic symptoms nor in length of time to first gastric emptying. Time to commencement of peristaltic-related emptying is delayed.     

Gastric Electrical Stimulation on Gastric Motility in Dogs

Aims: The aim of this study was to systematically evaluate and compare the effects of synchronized dual‐pulse gastric electrical stimulation (SDPS) and conventional gastric electrical stimulation (CGES) on antral contractions, gastric tone, and autonomic functions. Methods: Seven female hound dogs implanted with four pairs of electrodes on gastric serosa were studied in two separate experiments. The first experiment was designed to investigate the effects of SDPS/CGES on gastric tone and heart rate variations. The second experiment was performed to study the effects of SDPS/CGES on antral contractions. Results: 1) SDPS induced gastric antral contractions in the fasting state, whereas CGES at the intrinsic or a tachygastrial frequency had no effects on fasting antral contractions. 2) SDPS enhanced postprandial antral contractions impaired by glucagon; however, CGES at a tachygastrial frequency inhibited postprandial antral contractions. In addition, CGES at the intrinsic frequency of the stomach had no effects on postprandial antral contractions. 3) SDPS or CGES at the intrinsic frequency of the stomach had no effects on gastric tone, but CGES at a tachygastrial frequency reduced gastric tone. 4) SDPS excited vagal activity, but CGES at a tachygastrial frequency inhibited vagal activity. Conclusions: SDPS improves antral contractions but does not affect gastric tone and thus may have potential for treating gastric motility disorders. CGES at a tachygastrial frequency inhibits gastric tone and contractions and may be applicable for treating obesity. The excitatory or inhibitory effects of SDPS/CGES on gastric motility may be mediated via vagal pathway.     

Evaluation of gastric antral motor performance in patients with dysmotility-like dyspepsia using real-time high-resolution ultrasound

Abstract Although manometric antral hypomotility and delayed gastric emptying have been reported separately in patients with dyspepsia, relationships between symptoms, antral contractility and emptying rate have not been sought. The present study therefore aimed to evaluate, simultaneously, gastric antral excursion characteristics and emptying in a sub-group of patients with severe functional dyspepsia using high-resolution real-time ultrasound. The circumference of the relaxed and contracted antrum was measured at 15-min intervals after ingestion of a 360 mL mixed nutrient meal in 36 chronic dyspepsia patients with symptoms of post-prandial bloating and epigastric distension, and in 25 healthy volunteers. Antral emptying (measured as the rate of decrease in circumference of the relaxed antrum) was slower in patients than normals (P = 0.02). In both groups, the average values for antral excursion were similar but the range of excursion in patients was significantly wider than in controls (F < 0.001), with 11 patients showing values above, and 8 showing values below the normal range. There was no relationship between antral emptying and antral excursion in either patients or volunteers. In conclusion, patients with severe functional dyspepsia show a wide range of antral performance characteristics, suggesting not only that the mechanisms responsible for the control of antral motor function are disturbed but also that the cause of the symptoms and the disturbed antral motor function are probably not directly related.     

Influence of sumatriptan on gastric accommodation and on antral contraction in healthy subjects assessed by ultrasonography

Background Oral sumatriptan administration has been reported to delay gastric emptying after liquid meals. The aim of this study was to determine whether delayed gastric emptying is caused by enhanced gastric accommodation, impaired antral contractions, or both using ultrasonography. Methods Ten healthy volunteers were enrolled in this randomized two‐way crossover study. After overnight fasting, the subjects received the liquid meal 60 min after ingesting a 50 mg sumatriptan tablet with 50 mL of water or 50 mL of water alone (control). The cross‐sectional area of the proximal stomach was measured in a supine position after every 100 mL. The frequency and amplitude of the antral contractions were measured in a slightly backward sitting position. The intragastric distribution of the liquid meal was assessed by calculating the proximal stomach/distal stomach ratio (prox/distal ratio). Key Results The cross‐sectional area after drinking 100, 200, and 300 mL of the liquid meal (oral sumatriptan vs control) was 34.49 vs 15.11 cm² (P = 0.0051), 48.00 vs 30.61 cm² (P = 0.0166), and 58.67 vs 47.19 cm² (P = 0.0125), respectively. There was no significant difference in the amplitude of contractions, contraction cycle, motility index, and prox/distal ratio (97.15 vs 97.93%, P = 0.0745; 19.42 vs 19.5 s, P = 0.8590; and 887.58 vs 889.22, P = 0.5751; 9.75 vs 8.41, P = 0.8785; respectively). Conclusions & Inferences Oral sumatriptan administration enhanced gastric accommodation after the ingestion of liquid nutrients, but had no significant effect on antral contractions or intragastric distribution in healthy subjects.     

Effect of electrical stimulation on gastric electrical activity,motility and emptying

Abstract The aim was to measure the effect of gastric electrical stimulation on the frequency of canine antral pacesetter potentials (PPs), the strength of antral contractions, and the rate of gastric emptying while fasting, after feeding and with pentagastrin stimulation. Four conscious dogs with a stimulating electrode placed 10 cm proximal to the pylorus and recording electrodes and strain gauges placed 7, 5 and 3 cm proximal to the pylorus underwent myoelectric and strain gauge recordings while fasting, after feeding (250 ml 5% dextrose labelled with polyethylene glycol), and during pentagastrin infusion (0.5 μg kg^?1 min^?1) on four separate days. On each day, electrical stimulation was done using one of four stimulation frequencies (0, 6, 30 and 1200 stimuli per minute ***[s.p.m.]). Stimulation at 6 and 30 s.p.m. increased the fasting and fed PP frequency, whereas 1200 s.p.m. stimulation did not. Feeding decreased the maximum driven frequency, and pentagastrin increased it. Neither the motility index nor the gastric emptying rate were consistently changed by stimulation at any frequency. In conclusion, canine proximal antral stimulation at 6 and 30 s.p.m. sped PP frequency during fasting and after feeding, but stimulation over a wide range of frequencies had little effect on gastric contractions and emptying.     

Gastric emptying of a non-digestible solid: assessment with simultaneous SmartPill pH and pressure capsule, antroduodenal manometry, gastric emptying scintigraphy

Abstract  Gastric emptying of digestible solids occurs after trituration of food particles. Non-digestible solids are thought to empty with phase III of the migrating motor complex (MMC). The aim of this study was to determine if a non-digestible capsule given with a meal empties from the stomach with return of the fasting phase III MMC or during the fed pattern with the solid meal. Fifteen normal subjects underwent antroduodenal manometry and ingestion of a radiolabelled meal and SmartPill wireless pH and pressure capsule. In five subjects, emptying of the SmartPill was studied in the fasting period by ingesting the SmartPill with radiolabelled water. The SmartPill emptied from the stomach within 6 h in 14 of 15 subjects. SmartPill pressure recordings showed high amplitude phasic contractions prior to emptying. SmartPill gastric residence time (261 ± 22 min) correlated strongly with time to the first phase III MMC (239 ± 23 min; r  = 0.813; P  < 0.01) and correlated moderately with solid-phase gastric emptying ( r  = 0.606 with T-50% and r  = 0.565 with T-90%). Nine of 14 subjects emptied the capsule with a phase III MMC. In five subjects, the SmartPill emptied with isolated distal antral contractions. In five subjects ingesting only water, SmartPill gastric residence time (92 ± 44 min) correlated with the time to the first phase III MMC (87 ± 30 min; r  = 0.979; P  < 0.01). The non-digestible SmartPill given with a meal primarily empties from the stomach with the return of phase III MMCs occurring after emptying the solid-phase meal. However, in some subjects, the SmartPill emptied with isolated antral contractions, an unappreciated mechanism for emptying of a non-digestible solid.     

Video-based spatio-temporal maps for analysis of gastric motility in vitro: effects of vagal stimulation in guinea-pigs

Our aim was to evaluate topographically specific gastric motility changes induced by graded vagal activation. A recently developed method of constructing spatio-temporal maps of motility from video movies was adapted to the in vitro perfused guinea-pig stomach with an intact vagal nerve supply. In the unstimulated preparation, spontaneous activity was low or absent. Bilateral vagal stimulation with frequencies as low as 0.2 Hz triggered weak anally, and in some cases orally, propagating antral contractions at rates of about 5-6 min-1. Upon stimulation with higher frequencies, antral contractions increased significantly in length (starting more proximally) and amplitude, and produced large pressure peaks of up to 25 hPa, with maximal effects at 2-4 Hz. In contrast, the speed of propagation and the interval between peristaltic waves did not change with vagal stimulation at any frequency. Vagal stimulation also produced a significant and frequency-dependent enlargement of the fundus with a maximal effect at 4 Hz. It is concluded that a very low tonic vagal activity is apparently necessary and sufficient to express basic antral motility, while more sustained vagal activity is necessary for high-amplitude gastric contractions and significant sustained fundic relaxation. The constant interval between propagating contractions supports the concept that vagal input impinges on intrinsic enteric neural circuits that have a modulatory role in the myogenic mechanism underlying slow-wave peristalsis, rather than directly on gastric musculature.     

Volume estimation of the gastric antrum and the gallbladder in patients with non-ulcer dyspepsia and erosive prepyloric changes, using three-dimensional ultrasonography

Abstract Background: Two-dimensional ultrasonography has shown a widened gastric antrum in patients with non-ulcer dyspepsia (NUD) and erosive prepyloric changes (EPC).
Methods: In this study, volumes of gastric antrum and gallbladder were estimated with three-dimensional (30) ultrasonography before and after ingestion of 500 ml meat soup in 17 NUD with EPC patients and in 18 healthy subjects. A mechanical ultrasound scanner, coupled to a stepping motor, tilted the transducer through an angle of 51° or 88° while recording a total of 95 or 81 images, respectively. Volume estimation was performed digitally after interactive manual contour tracing and organ reconstruction in three dimensions.
Results: Antral volumes were larger in NUD patients than in healthy controls (P = 0.001). Fasting gallbladder volumes were similar in the two groups. Postprandial antral filling was more pronounced in patients than in healthy subjects (P = 0.02). whereas gallbladder emptying was more pronounced in healthy subjects than in patients (P = 0.05). The soup induced dyspeptic symptoms in 15 NUD patients, but only had this effect in two healthy subjects (P < 0.001).
Conclusion: Patients with NUD and EPC are characterized by abnormal antral filling, reduced gallbladder emptying, and dyspeptic symptoms in response to ingestion of meat soup.