Xiaohong Xu

Multichannel electrogastrography (EGG) in normal subjects: a multicenter study.

The aim of this study was to record gastric myoelectric activity using multichannel electrogastrography (EGG) and to determine if there are differences due to age, gender, body mass, and study location. In 61 normal subjects from four centers, fasting multichannel EGG was recorded for 1 h, followed by two 1-h postprandial recordings after a test meal. Variables assessed included dominant frequency (DF) and its power, percentage time in 2- to 4-cpm frequency, and percentage slow-wave coupling (%SWC). There were no significant differences in EGG parameters with respect to gender or age. Subjects with a BMI >25 had a decrease in the absolute DF power but a similar increase in the postprandial DF power. Subjects with a BMI >25 had a postprandial decrease in the %SWC compared to those with a BMI <25. There was a decrease in postprandial %SWC in European/Asian centers compared to American centers. In conclusion, multichannel EGG provides assessment of electrical slow-wave coupling in addition to determining dominant frequency, power, and percentage normal rhythm. This multicenter study of normal subjects shows similar multichannel EGG values among different genders and ages. Body mass and ethnicity may impact on some of the EGG values.

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.

Effects of enhanced viscosity on canine gastric and intestinal motility

Background and Aim: The aim of this study was to investigate the effect of enhanced viscosity on gastric emptying and gastrointestinal motor and myoelectrical activities in dogs.

Chronic Tachygastrial Electrical Stimulation Reduces Food Intake in Dogs

Objective: Tachygastria is known to be associated with gastric hypomotility. This study investigated the effect of tachygastrial electrical stimulation (TES) on food intake and its effects on gastric motility.

Alteration of gastric myoelectrical and autonomic activities with audio stimulation in healthy humans.

Objective Cold or emotional stress was reported to affect gastric myoelectrical activity. The aim of this study was to investigate the effects of music or noise on gastric myoelectrical activity and autonomic function in healthy volunteers. Material and methods The study was performed in 10 fasted healthy volunteers and included 30 min at baseline, 30 min of classical music via headphones and 30 min of loud household noises via headphones. The electrogastrogram (EGG) readings were recorded simultaneously with the electrocardiogram (ECG) recording. Results Both classical music and noise altered the regularity of gastric slow waves. The percentage of normal 2–4 cycles/min (cpm) waves was reduced from 77.9±4.7% at baseline to 66.9±5.4% during music (p<0.006) and 67.7±5.4% during noise (p<0.05). The reduction was attributed to a significant increase in bradygastria (15.8±3.9% versus 9.8±2.6%, p<0.04) with the music and a significant increase in arrhythmia (7.4±1.6% versus 2.0±1.1%, p<0.02) with the noise. The dominant frequency and power of the EGG were, however, not altered with either music or noise. Neither music nor noise had any effect on the autonomic function assessed by the heart rate variability. Conclusions Audio stimulation, with both music and noise, alters the rhythmicity of gastric slow waves. Classical music seems to increase bradygastria, whereas, household noise may increase arrhythmia. The effect of audio stimulation on the gastric slow wave does not seem to involve sympathetic or vagal efferent pathways assessed by the spectral analysis of heart rate variability.

Effects of audio stimulation on gastric myoelectrical activity and sympathovagal balance in healthy adolescents and adults

Aim:u2002 The primary aim of this study was to investigate the effects of different audio stimulations on gastric myoelectrical activity and sympathovagal balance in adolescents compared with adults.

Reverse gastric pacing reduces food intake without inducing symptoms in dogs.

Objective. To investigate the therapeutic potential of reverse gastric pacing (RGP) for obesity by studying the effects of RGP on food intake and symptoms in dogs. Material and methods. The study was performed in 9 dogs in 3 sessions (control, strong RGP and moderate RGP). Gastric myoelectrical activity and food intake were measured in each session. RGP was performed using serosal electrodes implanted in the distal stomach at the physiological frequency of the intrinsic gastric myoelectrical activity with a pulse width of 550–950 ms. The amplitude of the stimulus was set at a level maximally tolerable by the animals in the strong RGP session and 50% of the maximum level in the moderate session. Results. 1) Compared with the control, strong RGP (p<0.001) and moderate RGP (p<0.01) significantly reduced the amount of food intake by 62.9% and 31.7%, respectively (p<0.05, ANOVA). 2) Whereas strong RGP induced significant symptoms, moderate RGP did not induce any significant symptoms in comparison with the control session. 3) The regularity and coupling of gastric myoelectrical activity were significantly impaired with both strong RGP and moderate RGP in the fasting state. Conclusions. RGP impairs intrinsic gastric myoelectrical activity and substantially and acutely reduces food intake. The reduced food intake and freedom from symptoms resulting from moderate RGP are indicative of the therapeutic potential of RGP in obesity.

Impaired gastric slow wave rhythmicity in patients after bone marrow or stem cell transplant.

Patients after bone marrow or stem cell transplant often develop gastrointestinal symptoms. The aim of this study was to investigate possible impairment of gastric myoelectrical activity in these patients. The study was performed in 15 patients who had had bone marrow or stem cell transplant and 13 healthy subjects. Gastric myoelectrical activity was assessed using electrogastrography. The electrogastrogram (EGG) was made for 30 min in the fasting state and 60 min after a test meal (475 kcal; turkey sandwich). Overall and minute-by-minute spectral analyses were performed to derive various parameters of the EGG. Compared with the healthy controls, the patients showed a significantly higher percentage of arrhythmia (no obvious rhythmicity observed in the EGG) in both fasting (17.6 ± 3.8% vs 7.1 ± 2.17%, P < 0.02) and fed (11.4 ± 2.65% vs 4.19 ± 1.04%, P < 0.02) state. The patients showed a significantly higher instability coefficient of the dominant frequency in the fasting state than in the controls (0.51 ± 0.06 vs 0.29 ± 0.18, P < 0.008). The total average symptom score was 3.93 ± 0.84 in the patients and 0 in the controls, and a relatively weak but significant correlation was found between the symptom scores and the percentage of arrhythmia in the patients in fed state (r = 0.69, P < 0.02). It was concluded that patients with bone marrow or stem cell transplant have excessive arrhythmia that is correlated with their dyspeptic symptoms.

Chronic Electrical Stimulation at Acupoints Reduces Body Weight and Improves Blood Glucose in Obese Rats via Autonomic Pathway.

BackgroundThe aim of this study was to investigate effects and mechanisms of chronic electrical stimulation at acupoints (CEA) using surgically implanted electrodes on food intake, body weight, and metabolisms in diet-induced obese (DIO) rats.MethodsThirty-six DIO rats were chronically implanted with electrodes at acupoints ST-36 (Zusanli). Three sets of parameters were tested: electrical acupuncture (EA) 1 (2-s on, 3-s off, 0.5xa0ms, 15xa0Hz, 6xa0mA), EA2 (same as EA1 but continuous pulses), and EA3 (same as EA2 but 10xa0mA). A chronic study was then performed to investigate the effects of CEA on body weight and mechanisms involving gastrointestinal hormones and autonomic functions.ResultsEA2 significantly reduced food intake without uncomfortable behaviors. CEA at EA2 reduced body weight and epididymal fat pad weight (Pu2009<u20090.05). CEA reduced both postprandial blood glucose and HbA1c (Pu2009<u20090.05). CEA delayed gastric emptying (Pu2009<u20090.03) and increased small intestinal transit (Pu2009<u20090.02). CEA increased fasting plasma level of glucagon-like peptide-1 (GLP-1) and peptide YY (Pu2009<u20090.05); the increase of GLP-1 was inversely correlated with postprandial blood glucose (R2u2009=u20090.89, Pu2009<u20090.05); and the plasma ghrelin level remained unchanged. EA increased sympathetic activity (Pu2009<u20090.01) and reduced vagal activity (Pu2009<u20090.01).ConclusionsCEA at ST-36 reduces body weight and improves blood glucose possibly attributed to multiple mechanisms involving gastrointestinal motility and hormones via the autonomic pathway.

Inhibitory effects of sildenafil on small intestinal motility and myoelectrical activity in dogs

Previous studies have shown that sildenafil inhibits the esophageal motility in both humans and animals. The aim of this study was to investigate the effects of sildenafil on intestinal myoelectrical activity and motility. The study was composed of 2 experiments and performed in 7 healthy female dogs with a duodenal cannula 20 cm beyond pylorus (19–26 kg). The first experiment was designed to study the effects of sildenafil on intestinal myoelectrical activity and it included 2 sessions each consisting of 30-minute baseline, 15-minute posttreatment (placebo or 100 mg sildenafil) and 90 minutes after a liquid meal. Intestinal myoelectrical activity was recorded during the entire experiment period. The second experiment was aimed to investigate the effect of sildenafil on intestinal motility and was performed immediately after a solid meal. Intestinal motility was measured by a manometric catheter inserted into the small intestine via the duodenum cannula for 30 minutes at baseline and 60 minutes after sildenafil. Sildenafil significantly reduced the amplitude but had no effect on the frequency and regularity of the intestinal myoelectrical activity. Sildenafil significantly inhibited postprandial intestinal contractions. Although the frequency of the contractions was not altered, the mean area under the curve was significantly reduced during the first 30 minutes (P < .03) and second 30 minutes after sildenafil (P < .03); the power of intestinal contractile activities was also significantly reduced during the first 30 minutes (P < .0004) and second 30 minutes after sildenafil (P < .0003) in comparison with baseline. In conclusion, sildenafil inhibits the amplitude of both intestinal contractile activity and intestinal slow waves.