Effect of two-channel gastric electrical stimulation with trains of pulses on gastric motility

AIM： To investigate the effect of two-channel gastric electrical stimulation （GES） with trains of pulses on gastric emptying and slow waves.METHODS： Seven dogs implanted with four pairs of electrodes and equipped with a duodenal cannula were involved in this study. Two experiments were performed.The first experiment included a series of sessions in the fasting state with trains of short or long pulses, each lasted 10 min. A 5-min recording without pacing was made between two sessions. The second experiment was performed in three sessions （control, single-channel GES, and two-channel GES）. The stimulus was applied via the 1st pair of electrodes for single-channel GES （GES via one pair of electrodes located at 14 cm above the pylorus）, and simultaneously via the 1st and 3rd channels for two-channel GES （GES via two pairs of electrodes located at 6 and 14 cm above the pylorus）, Gastric liquid emptying was collected every 15 min via the cannula for 90 min.RESULTS： GES with trains of pulses at a pulse width of 4 ms or higher was able to entrain gastric slow waves. Two-channel GES was about 50% more efficient than single-channel GES in entraining gastric slow waves. Two-channel but not single-channel GES with trains of pulses was capable of accelerating gastric emptying in healthy dogs. Compared with the control session, two-channel GES significantly increased gastric emptying of liquids at 15 rain （79.0% ± 6.4% vs 61.3% ± 6.1%, P 〈 0.01）, 30 min （83.2% ± 6.3 % vs 68.2% ± 6.9%, P 〈 0.01）, 60 min （86.9% ± 5.5 % vs 74.1% ± 5.9%, P 〈 0.01）, and 90 rain （91.0% ± 3.4% vs 76.5% ± 5.9%, P 〈 0.01）.CONCLUSION： Two-channel GES with trains of pulses accelerates gastric emptying in healthy dogs and may have a therapeutic potential for the treatment of gastric motility disorders.     

Effects of Gastric Electrical Stimulation with Short Pulses and Long Pulses on Gastric Dysrhythmia and Signs Induced by Vasopressin in Dogs

Aims: This study was to investigate the effect of gastric electrical stimulation (GES) with short pulses, long pulses, short-pulse trains or long-pulse trains on gastric dysrhythmia and motion-sickness signs induced by vasopressin. Methods: Seven male beagle dogs implanted with four pairs of electrodes on gastric serosa were studied. The study was performed in six sessions in a randomized order. In session 1 or 2, either saline or vasopressin was infused without GES. In session 3, 4, 5 and 6, GES with short pulses, long pulses, trains of short pulses or trains of long pulses was performed before and during vasopressin infusion. Gastric slow waves and motion-sickness signs were recorded in each session. Results: (1) Vasopressin induced gastric dysrhythmia and motion sickness-like signs (ANOVA, P < 0.001). (2) GES with short pulses or trains of short pulses was capable of preventing vasopressin-induced emetic response (P < 0.001), but did not normalize gastric dysrhythmia. (3) GES with long pulses or trains of long pulses was able to normalize gastric dysrhythmia induced by vasopressin (P < 0.001), but showed no effects on vasopressin-induced motion-sickness signs. Conclusion: GES with short pulses or trains of short pulses prevents vasopressin-induced emetic response with no improvement in gastric dysrhythmia. GES with long pulses or trains of long pulses normalizes gastric dysrhythmia induced by vasopressin with no effects on signs. Xiaohua Hou and Geng-Qing Song contributed equally to this work.     

Impairment of Gastric and Jejunal Myoelectrical Activity During Rectal Distension in Dogs

It is known that distension of the rectum induces gastric hypomotility and delays gastric emptying. Its effect on gastrointestinal myoelectrical activity has not been well studied, however. The aim of this study was to investigate the effects of rectal distension on gastrointestinal myoelectrical activity in dogs. Six hound dogs implanted with electrodes on the serosa of the stomach and proximal jejunum were studied. The protocol consisted of a 30-min baseline recording and another 30-min recording during rectal distension. Gastric myoelectrical activity was severely impaired by rectal distension. The dominant power was significantly decreased from –2.79 ± 0.52 dB at baseline to –4.84 ± 1.26 dB during distension (P < 0.05). The percentage of normal 4–6 cycles per minute gastric slow waves was reduced from 95.08 ± 1.11% to 83.63 ± 4.00% (P < 0.02), and the percentage of tachygastria was increased during distension (0.33 ± 0.19% vs 6.03 ± 1.27%, P < 0.02). The instability coefficient of the dominant frequency was significantly increased (0.134 ± 0.012 vs 0.326 ± 0.074, P < 0.05). The percentage of slow wave coupling was reduced from 93.99 ± 0.76% to 73.43 ± 2.07% (P < 0.00003). In the small bowel, only the instability coefficient of dominant frequency showed a significant increase during distension. Other parameters were not affected by rectal distension. We conclude that rectal distension severely impairs gastric myoelectrical activity. The induced gastric dysrhythmia and reduced slow wave amplitude and coupling may be the underlying pathophysiology of gastric hypomotility and delayed gastric emptying observed during rectal distension.     

Hyperglycemia Attenuates Erythromycin-Induced Acceleration of Liquid-Phase Gastric Emptying of Hypertonic Liquids in Healthy Subjects

Acute hyperglycemia has been associated with delayed gastric emptying in healthy controls. Erythromycin has recently been found to be a gastrointestinal prokinetic agent in both solids and hypertonic liquids. Our aim was to examine whether the acute steady-state hyperglycemia reduces the erythromycin-induced acceleration of gastric emptying of hypertonic liquids after a fasted state of the stomach in healthy subjects. In 12 healthy subjects scintigraphic measurement of gastric emptying of a hypertonic radiolabeled liquid meal, during normoglycemia (5–8.9 mmol/l glucose) or induced hyperglycemia (16–19 mmol/liter glucose) by intravenous glucose infusion after giving either placebo or 200 mg intravenous erythromycin, was performed on four separate days in random order. In the hyperglycemic state compared with normoglycemia, either after placebo administration or erythromycin, the gastric emptying of the hypertonic liquid was reduced. The lag-phase duration was significantly increased (17.5 ± 5.5 min, and 7.2 ± 4.5 min vs 10.5 ± 3.4 min, and 3.5 ± 2.5 min, respectively, P < 0.0001) as were the overall T1/2 (gastric emptying time of the half meal) (52.5 ± 13 min and 24.5 ± 5.5 min vs 42 ± 10.5 min, and 16 ± 6 min, respectively, P < 0.0001) and the percentage of liquid meal retained in the stomach at 60 and 100 min postprandially (P < 0.001). In conclusion, hyperglycaemia attenuates the acceleration effect of erythromycin and decreases the overall gastric emptying rate of hypertonic liquids in healthy subjects.     

Gastric dysrhythmias following pylorus-preserving pancreaticoduodenectomy

Transient delayed gastric emptying is reported as a frequent complication following pancreas-preserving pancreaticoduodenectomy (PPW). We placed serosal electrodes on the stomach of a patient undergoing PPW. Myoelectric recordings were obtained postoperatively and correlated with simultaneous radionuclide liquid gastric emptying studies. The patient developed early postoperative gastric atony, associated with frequent gastric dysrhythmias. These dysrhythmias may have been exacerbated by a perihepatic abscess. The gastric dysrhythmias correlated with alterations in liquid gastric emptying. Gastric dysrhythmias may be a mechanism for gastric dysfunction in the early postoperative period.This work was supported by the Medical Research Service of the VA Medical Center, Gainesville, Florida.     

Helicobacter pylori Infection Is Not Associated with Delayed Gastric Emptying or Upper Gastrointestinal Symptoms in Diabetes Mellitus

This study evaluated the relationship between gastric emptying and upper gastrointestinal symptoms with H. pylori status in patients with diabetes mellitus. Sixty-three outpatients (44 type 1, 19 type 2, age 45 ± 1.5 years) underwent measurements of gastric emptying of a mixed solid and liquid meal, gastrointestinal symptoms (gastric and esophageal), glycemic control (HbA_lc), and autonomic nerve function. Anti-H. pylori IgG antibodies were quantified using a validated kit. Gastric emptying of solid and/or liquid was delayed in 47 (75%) patients, and 31 (49%) had autonomic neuropathy. Fifteen (24%) of the patients were H. pylori positive. There were no differences in gastric emptying (solid retention at 100 min: 67.5 ± 5.7% vs 63.2 ± 3.6%; P = 0.63, liquid T50: 35.5 ± 2.9 min vs 42.5 ± 3.4 min; P = 0.42), upper gastrointestinal symptoms (gastric 3.9 ± 0.7 vs 4.0 ± 0.4; P = 0.94 or esophageal 1.7 ± 0.5 vs 1.3 ± 0.2; P = 0.42) or HbA_lc (8.8 ± 0.4% vs 8.6 ± 0.2%; P = 0.89) between H. pylori-positive and -negative patients. We conclude that H. pylori infection is not associated with delayed gastric emptying or upper gastrointestinal symptoms in diabetes.     

Gastric emptying in Mexican Americans compared to non-Hispanic whites

Mexican Americans, a group at high risk for type II diabetes mellitus, have higher postprandial insulin and glucose levels when compared to non-Hispanic whites. A rapid rate of gastric emptying contributes to an increased rate of nutrient absorption and subsequent greater elevation of postprandial glucose and insulin levels. A more rapid rate of gastric emptying and hyperinsulinemia have been observed in patients with recently diagnosed type II diabetes mellitus. In this study, we examined whether Mexican Americans have a more rapid rate of gastric emptying than non-Hispanic whites. Gastric emptying studies were performed on 32 nondiabetic Mexican Americans and on 31 nondiabetic non-Hispanic whites. The rate of gastric emptying following a liquid glucose meal was measured. Serum insulin, plasma glucose, and GIP levels were measured in fasting and postprandial blood samples collected at 15-min intervals for 2 hr. Adjusting for age, body mass index, and gender, the gastric half-emptying time of a glucose meal was significantly (P<0.05) more rapid for the Mexican American subjects (56.5±3.4 min) compared to the non-Hispanic white subjects (66.4±3.5 min). Nondiabetic Mexican Americans empty a liquid glucose meal more rapidly from their stomachs than nondiabetic non-Hispanic whites. Rapid gastric emptying is associated with hyperinsulinemia as a normal physiologic response to increased nutrient availability. The rapid gastric emptying observed in nondiabetic Mexican Americans is associated with hyperinsulinemia and could be a contributing factor for the increased risk of obesity and type II diabetes in this population.Funding for this research was provided by the South Texas Health Research Center.     

Influence of blood glucose levels on rat liquid gastric emptying

The glycemic influence on liquid gastric emptying in rats was studied. Diabetic hyperglycemia was induced by streptozotocin intravenous injection seven days before the motility experiment. Some streptozotocin-treated rats further received a daily insulin injection (2.5 or 10 IU/kg). Immediate hyperglycemia was induced in a separate group of rats by continuous intravenous glucose infusion (44 or 88 mg/kg/min) 10 min before the experiment. Rats were killed 15 min after radiochromium feeding; then the radioactivity of stomach and small intestine were counted to obtain the gastric emptying value. Emptying in diabetic rats was delayed compared with controls (mean±se: 40.9±2.6% vs. 54.2±2.8%,P<0.01). Low-dose insulin treatment reversed the impairment, while high-dose treatment even enhanced emptying. Immediate hyperglycemia induced with two glucose infusions also inhibited gastric emptying. Present results indicate that hyperglycemia elicited with any hyperglycemic model is at least one of the important mechanisms to delay liquid gastric emptying.This study was supported by the National Science Council, Republic of China, grant NSC 84-2331-B-075-68.     

Simultaneous measurement of gastric emptying with a simple muffin meal using [13C]octanoate breath test and scintigraphy in normal subjects and patients with dyspeptic symptoms

The objective of this study was to determine how the [¹³C]octanoate breath test (OBT) using a muffin meal correlates with gastric emptying scintigraphy (GES) in normal subjects and patients with dyspeptic symptoms. Ten normal subjects and 23 patients with dyspeptic symptoms underwent simultaneous GES and [¹³C]OBT. After an overnight fast, a muffin labeled with [^99mTc]sulfur colloid and [¹³C]octanoate was ingested along with water labeled with [¹¹¹In]DTPA. Breath samples and scintigraphic images were obtained at baseline and at regular postprandial intervals over 6 hr. In the normal subjects, the mean GES T1/2 of solids and liquids were 64 ± 17 and 55 ± 27 minutes, respectively. The calculated OBT T1/2 using the 6-hr breath collection was 138 ± 15 min and correlated with T1/2 for solids by GES (r = 0.664; P = 0.051), but did not correlate with T1/2 for liquids by GES (r = 0.13; P = 0.738). In dyspeptic patients, the T1/2 for GES was 87 ± 53 min and 81 ± 70 min for solids and liquids, respectively. The mean OBT T1/2 was 155 ± 57 min and correlated with GES T1/2 for solids (r = 0.86; P < 0.001) and GES T1/2 for liquids (r = 0.73; P < 0.001). Delayed gastric emptying (GE) of the muffin meal was identified by scintigraphy in seven patients. The sensitivity and specificity for OBT identifying delayed GE were 86% and 94%. Use of the initial truncated 4-hr OBT results also revealed a significant correlation between OBT and GES T1/2 for solids (r = 0.86; P < 0.001) with sensitivity and specificity for detecting delayed GE of 86% and 94%, respectively. In addition, a linear regression model was able to reduce the number of collection points to four, while maintaining the same sensitivity and specificity. In conclusion, the OBT for GE, using an easily prepared muffin meal, significantly correlates with GES for solids. This muffin-based OBT is a sensitive and specific method to detect delayed GE in dyspeptic patients.     

Gastric emptying response to variable oral erythromycin dosing in diabetic gastroparesis

Intravenous erythromycin has been shown to improve gastric emptying in diabetic gastroparesis. Oral erythromycin also accelerates gastric emptying, but to a lesser degree. To determine if this is a dose-dependent phenomenon, gastric emptying was measured in 10 insulin-requiring diabetic patients with gastroparesis after administration of either 250 mg or 1000 mg of erythromycin or placebo. The drugs were orally administered in a randomized, double-blind fashion 30 min prior to ingestion of a meal containing [^99mTc]-sulfur colloid-labeled beef stew and [¹¹¹In]DTPA-labeled orange juice. Anterior and posterior gastric images were recorded for 3 hr at 15-min intervals using an externally positioned gamma camera. The results demonstrated that both doses of oral erythromycin significantly improved solid-phase gastric emptying. The mean half-emptying time of solids was decreased from 151±40 min with placebo to 58±10 min and 40±9 min with 250 mg and 1000 mg of erythromycin, respectively. However, a dose-dependent relationship was not demonstrated with the two doses of erythromycin employed. These results suggest that for most patients with diabetic gastroparesis, a single 250-mg dose of erythromycin will significantly improve gastric emptying. It is possible that a dose-dependent relationship will be demonstrated with doses of erythromycin less than 250 mg.     

Extending Gastric Emptying Scintigraphy from Two to Four Hours Detects More Patients with Gastroparesis

Gastric emptying scintigraphy (GES) is usually performed for up to 2 hr to measure the gastric emptying (GE) of solids. Symptomatic patients, however, may have borderline results at 2 hr, making it difficult to determine whether a gastric motor disorder is present. The aim of this study was to assess whether extending GES to 4 hr is useful in evaluating patients for gastroparesis and to correlate the results of GES with patient symptoms. We studied 129 patients undergoing GES at Temple University Hospital between July 1998 and March 1999. Solid-phase GE was measured at 0, 0.5, 1, 2, 3, and 4 hr after ingestion of a ^99mTc sulfur colloid-labeled egg meal. Dyspeptic symptoms of upper abdominal discomfort, early satiety, postprandial abdominal bloating, nausea, vomiting, and anorexia were graded as none, mild, moderate and severe (0, 1, 2 and 3, respectively) with the sum representing a total symptom score. Of 129 patients, 86 had normal GE at 2 hr; 26 of the 86 normal scans at 2 hr were delayed at 3 hr. Six of the 60 scans normal at 2 and 3 hr were delayed at 4 hr. Of 43 patients with delayed GE at 2 hr, 39 were delayed at 3 hr and 35 were delayed at 4 hr. Overall, the percentage of patients with delayed GE increased from 33% at 2 hr only to 58% using the results of the 2-, 3-, and 4-hr scans (P < 0.05). There was a significantly greater symptom score in patients with delayed GE compared to patients with normal GE (8.4 ± 0.5 vs 7.1 ± 0.5; P < 0.05). Conclusion, prolonging GES after ingestion of a ^99mTc-labeled egg meal from 2 to 4 hr increased the number of symptomatic patients found to have delayed GE. These results suggest that GES should be performed for up to 4 hrs when the 2-hr result is normal.     

Gastric emptying: a comparison of three methods

Objective. A better understanding of the clinical relevance of delayed gastric emptying (e.g. in diabetes) requires a simple, easily accessible and inexpensive method for measuring it. Two “new” methods for measuring gastric emptying of liquids (the paracetamol absorption test and the ¹³C-acetate breath test) are compared with the gold standard (gastric emptying scintigraphy (GES)). Material and methods. The three techniques were used simultaneously in 10 healthy subjects. A gastric emptying time-retention curve was drawn for each technique and the results were compared at the 75%, 50% and 25% retention quartiles. Results. Agreement was found between the paracetamol absorption test and GES (p=0.95; Hotelling's T² test). Using the Wagner-Nelson one compartment correction produced a retention curve for the ¹³C-acetate breath test statistically significantly below GES (p<0.01). Conclusion. In healthy subjects, the paracetamol absorption test produced results comparable to those of liquid GES, but not to the results of the ¹³C-acetate breath test.     

Gastric emptying in diabetic patients by the 13C-octanoic acid breath test: role of insulin in gastric motility

Background Impairment of gastric emptying is well recognized in patients with diabetes mellitus (DM), especially long-standing insulin-dependent diabetes mellitus (IDDM). The aim of this study was to evaluate the cause of delayed gastric emptying in DM patients. Methods In 16 controls, 16 non-insulin-dependent diabetes mellitus (NIDDM) patients and 23 IDDM patients, gastric emptying was studied using the ¹³C octanoic acid breath test. Breath samples were taken before a test meal labeled with 100 mg of ¹³C octanoic acid, and at 15-min intervals over a 300-min period postprandially. Results In all DM patients, the gastric emptying coefficient was lower than that in the controls (P < 0.05), and lag time and half-emptying time were significantly longer (P < 0.05). Both NIDDM and IDDM patients showed delayed ¹³CO₂ excretion compared with the controls, but IDDM patients showed more delayed gastric emptying than NIDDM patients (P < 0.05). There were no significant differences in sex, HbA1c level, or the rate of neuropathy between the two groups. Conclusions IDDM patients showed delayed gastric emptying compared with NIDDM patients, and the ¹³C octanoic acid breath test is useful for evaluating DM patients with delayed gastric emptying.     

Inhibitory effects of gastric electrical stimulation on ghrelin-induced excitatory effects on gastric motility and food intake in dogs

Objective. To investigate the effects of ghrelin on food intake, gastric motility and whether gastric electrical stimulation (GES) is capable of reversing these effects of ghrelin in dogs. Material and methods. Seven healthy dogs were equipped with a gastric cannula and electrodes for the measurement of antral motility and gastric myoelectrical activity (GMA). Both food intake and gastric motility studies were performed in three sessions (control, ghrelin, 20 µg and ghrelin plus GES) in randomized order, respectively. After a 28-h fast, the animals were provided with unlimited solid food for 1.5?h, 30?min after saline or ghrelin injection. Recordings of antral contractions and GMA in each session were recorded for 30?min at baseline and 45?min after ghrelin/saline injection in the fasting state. GES was performed throughout the experiment initiated 30?min prior to the injection. Results. 1) Ghrelin significantly increased food intake from 475.6±75.5?g in the controls to 535.9±90.3?g with ghrelin (p=0.04); this excitatory effect was reversed by GES. 2) Ghrelin significantly increased the motility index from 8.6±1.6 in the controls to 16.1±2.4 with ghrelin (p=0.01) and this effect was also reversed by GES. 3). There were no effects of ghrelin on GMA. Conclusions. Ghrelin induces antral contractions and increases food intake. GES is capable of blocking these excitatory effects of ghrelin. These findings suggest that GES may inhibit the resistant effect of ghrelin on weight loss.     

Is There a One-to-One Correlation Between Gastric Emptying of Liquids and Gastric Myoelectrical or Motor Activity in Dogs?

The aim of this study was to investigate the correlation of gastric emptying with gastric myoelectrical activity recorded from internal serosal electrodes and with gastric motility measured from strain gauges. The study was performed in eight healthy dogs chronically implanted with four pairs of electrodes and two strain gauges on the gastric serosa and equipped with a duodenal fistula for the assessment of gastric emptying. Each dog was fed four liquid test meals on four separate days with identical calories (320 kcal) and volume (473 ml). A correlation was found between gastric emptying and the energy of contraction in the frequency band of 3.75–7.50 cycles/min during the first 30 min after the meal (r = 0.46, P < 0.05). While none of the parameters of gastric myoelectrical activity was correlated with gastric emptying, two major parameters, percentage of regular gastric slow waves and percentage of slow-wave coupling, were found to be associated with delayed gastric emptying. A significant correlation was found between the frequency of gastric slow waves and that of the contractions in both fasting (r = 0.83, P < 0.001) and fed state (r = 0.70, P < 0.001 at 30 min, r = 0.86, P < 0.001 at 60 min). It was concluded that gastric emptying is correlated with the strength of gastric contractions in a frequency range identical to that of the gastric slow waves, and there is no one-to-one correlation between gastric emptying of liquids and any parameters of gastric myoelectrical activity. However, major parameters of gastric myoelectrical activity are associated with gastric emptying.     

Efficacy of Gastric Electrical Stimulation in Improving Functional Vomiting in Patients with Normal Gastric Emptying

The objective of this study is to evaluate the utility of gastric electrical stimulation (GES) in the subgroup of patients with refractory nausea and vomiting in the presence of normal gastric emptying. Eighteen patients (15 females) underwent GES implantation for dyspeptic symptoms in the presence of normal gastric emptying. Upper gastrointestinal (UGI) symptom score, health-related quality of life (HR-QOL), nutritional status and weight, and medication use (prokinetics and antiemetics) were assessed at baseline and at 1 year after GES placement. Twelve patients (two males) were included in the final analysis. All patients had normal gastric emptying scintigraphy at baseline. After 1 year of GES, there was a significant reduction in the UGI symptom score from 18 to 10 (P = 0.001). The physical component score (PCS) of the HR-QOL was also significantly increased from 25 to 42 (P = 0.04). Gastric emptying actually became slower in 29% of those who repeated the test after 1 year. No adverse events related to GES placement were recorded. Results of our study suggest that GES improves dyspeptic symptoms in patients with medically refractory nausea and vomiting independent of its effect on gastric emptying and could be considered as a potential therapy in this clinical setting.     

Abnormal gastric myoelectrical activity and delayed gastric emptying in patients with symptoms suggestive of gastroparesis

Gastric myoelectrical activity modulates gastric motor activity. Abnormalities in gastric myoelectrical activity may be associated with gastric motility disorders. The aim of this study was to investigate the correlation of gastric myoelectrical activity with gastric emptying in symptomatic patients with and without gastroparesis. Ninety-seven patients with symptoms suggestive of gastroparesis participated in the study. Gastric myoelectrical activity was recorded using surface electrogastrography. The electrogastrogram (EGG) was recorded for 30 min in the fasting state and for 120 min after a solid test meal. Gastric emptying of the solid meal was simultaneously monitored for 120 min. Patients with delayed gastric emptying showed a significantly lower percentage of normal gastric slow waves (P<0.03) and a significantly reduced increase of the dominant power in the postprandial EGG (P<0.02). Postprandial EGG parameters were found to be able to predict delayed emptying of the stomach. Postprandial gastric dysrhythmia predicts delayed gastric emptying with an accuracy of 78%, while the abnormality in postprandial EGG power predicts delayed gastric emptying with an accuracy of 75%. All patients with abnormalities in both the rhythmicity and the power had delayed gastric emptying. Patients with delayed gastric emptying have a lower percentage of normal gastric slow waves in the EGG and a lower postprandial increase in the dominant power. Abnormalities in the postprandial EGG seem to be able to predict delayed emptying of the stomach. However, a normal EGG does not seem to guarantee normal emptying of the stomach.     

Chronic Gastric Electrical Stimulation for Gastroparesis Reduces the Use of Prokinetic and/or Antiemetic Medications and the Need for Hospitalizations

To investigate the effect of chronic gastric electrical stimulation (GES) on the daily use of prokinetics and antiemetics, hospitalizations, total symptom score (TSS), SF-36 status for health-related quality of life (HQOL), and gastric emptying of a solid meal, we evaluated 37 gastroparetic patients preoperatively and 1 year after undergoing GES implant. Prokinetic and antiemetic use was significantly reduced. Of 27 patients on at least one prokinetic at baseline, 8 were off at 1 year. Twenty-six patients requiring antiemetics before surgery decreased to 17. Mean TSS was significantly reduced and the reduction for patients off medications was significantly better than for patients still on medications. Overall SF-36 scores for HQOL were significantly improved, and patients off antiemetics had a significantly higher HQOL score than for patients on antiemetics at 1 year. Hospitalizations decreased from 50 ± 10 days for the year prior to GES therapy to 14± 3 days (P < 0.05). However, gastric emptying was not significantly improved. Conclusions are as follows. (1) Chronic GES significantly reduced the use of prokinetic/antiemetic medications and the need for hospitalization in gastropraretic patients, whose clinical and quality of life outcomes also significantly improved (2) These data provide evidence of the positive economic impact of this new therapy on long-term clinical outcomes in gastroparetic patients not responding to standard medical therapy.This study was supported in part by Medtronic, Inc. Part of this work was presented orally at the 2002 Annual AGA/DDW Meeting in San Francisco, California.     

Voluntary suppression of defecation delays gastric emptying

We wished to test the hypothesis that colonic loading with fecal material leads to delayed gastric emptying. Twelve healthy male volunteers were studied. Each of these subjects went through two randomized study periods of four days. In one of these, the subjects defecated upon urge, in the other period defecation was voluntarily suppressed. Gastric emptying of a semisolid meal (mashed potatoes) was measured with the noninvasive applied potential tomography technique. On day 3 no significant changes in gastric emptying were found, but on day 4 the emptying rate had decreased from 85.8±11.0%/hr (mean±sem) to 70.3±10.9%/hr (P<0.05) and the T50 had increased from 38.5±3.4 min to 46.2±4.0 min (P<0.025). The duration of the lag phase (4.1±1.5 min) was not significantly altered by suppression of defecation. Our conclusion is that voluntary suppression of defecation delays gastric emptying in normal subjects. This cologastric brake may be involved in the pathogenesis of upper abdominal symptoms in constipated patients.     

Gastric electrical stimulation using endoscopically placed mucosal electrodes reduces food intake in humans

BACKGROUND: Implantable gastric stimulation (IGS) has been proposed for treating obesity. The aim of this study was to investigate the effects of temporary mucosal electrical stimulation on water and food intake as well as gastric emptying in healthy humans. METHODS: The study was designed to study the effects of temporary gastric electrical stimulation (GES) on symptoms, gastric accommodation, food intake, and gastric emptying. It was performed in 12 healthy volunteers on 3 consecutive days. GES was performed using mucosal electrodes endoscopically placed in the fundus. RESULTS: The amount of maximum water intake was reduced with GES (894 +/- 326 mL) compared with sham-GES (1,093 +/- 417 mL, p = 0.01). The food intake was also reduced with GES (p = 0.012). In comparison with sham stimulation, GES delayed gastric emptying during the first 45 min after the meal but not during the remaining time. GES with parameters effective in reducing water and food intake and delaying gastric emptying did not induce significant dyspeptic symptoms, compared with sham stimulation. CONCLUSIONS: GES using temporary mucosal electrodes decreases food intake as well as maximum intake of water, and has a tendency of delaying gastric emptying. It may have a potential application for the treatment of obesity.