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PubMed1994

Daytime ingestion of alcohol alters nighttime jejunal motility in man.

We studied the effects of acute ingestion of intoxicating doses of alcohol on jejunal motility in six male volunteers ages 24-45 who had two 24-hr ambulatory manometries, one week apart, that each included three standardized meals with either red wine (0.6 g of alcohol/kg) or dealcoholized wine. Breath alcohol was measured at regular intervals for 3 hr following alcohol. The results show that the MMC cycle was significantly (P < 0.01) shorter during the night than during the day in the "nonalcohol" group but not in the "alcohol" group and that the amplitude of contractions was higher during the night than the day in the alcohol group (P < 0.01). All meals interrupted the MMC and induced a fed pattern. After the 300-kcal liquid meal, the duration of the fed pattern was shorter (P < 0.01), with a lower motility index (P < 0.01) and fewer contractions (P < 0.01), than following the two 600-kcal meals. The number of clustered contractions occurring in the postprandial period was lower in the alcohol group than in the nonalcohol group. After the three alcohol doses, a breath alcohol peak was reached in 20-60 min, and in all subjects, breath alcohol fell below 22 micrograms/100 ml after the third hour. This study showed that alcohol had only minor effects on postprandial contractile activity but abolished the circadian variation of the MMC normally seen in healthy subjects. The fact that breath alcohol was low by the time of onset of sleep, suggests that the effects on the MMC may be mediated through central rather than local mechanisms.

Adult↗
PubMed1994

Impaired interdigestive pancreatic polypeptide release. Early hormonal disorder in chronic pancreatitis?

The purpose of this study was to investigate interdigestive cycling and postprandial release of pancreatic polypeptide (PP) in relation to exocrine pancreatic function in chronic pancreatitis (CP). We investigated nine patients with mild-moderate CP (MCP), eight patients with severe CP and steathorrea (SCP), and 17 healthy subjects as controls. Interdigestive antroduodenal motility was monitored by means of manometry. Following two consecutive motility cycles, a standard test meal was administered. Plasma samples were drawn for PP determinations every 15 min throughout the entire study, which concluded 2 hr after ingestion of the meal. Mean interdigestive PP plasma concentrations during phase III motor activity were lower in MCP (146 +/- 46 pg/ml) than in controls (270 +/- 42 pg/ml) and lower still in SCP (55 +/- 8 pg/ml). Accordingly, the percent increase in PP concentrations during phase III over those in phase I was progressively decreased from controls (112%) to MCP (62%) to SCP (19%). Mean interdigestive PP concentrations were also lower during phase I and II in SCP than in controls or MCP. None of the postprandial parameters for PP release was affected in the early stage of disease, while mean, peak, and integrated postprandial values were significantly lower in SCP than in controls or MCP. Thus, we observed a progressive diminution of both interdigestive and postprandial PP release with increasing severity of disease. Interdigestive release parameters, in particular, were tightly correlated with exocrine function. CP appears to alter interdigestive PP release to a greater extent than postprandial PP release; this effect is already apparent in early stages of the disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Erythromycin accelerates solid emptying at the expense of gastric sieving.

Erythromycin accelerates gastric emptying by inducing antral contractions similar to phase III of interdigestive MMC. These powerful contractions are capable of forcing coin-sized indigestibles out of the stomach. In contrast, fed motility is associated with submaximal contractions that fragment (trituration) and propel solids while retaining large (> 0.5 mm) pieces for further size reduction (gastric sieving). In this study, using dogs with duodenal fistulas, we tested the hypothesis that erythromycin-induced acceleration of gastric emptying resulted in the passage of inadequately triturated (> 0.05 mm) chunks of solids into the duodenum. We found that gastric emptying was accelerated by erythromycin (vs 0.15 M NaCl control, P < 0.05). However, the percentage of chyme collected in the > 0.5-mm fraction was much greater (P < 0.01) in the erythromycin-treated experiments (63 +/- 9%) than the controls (7 +/- 1%). Correspondingly, while a fine gruel was passed during controls, under erythromycin infusion, most of the solids were emptied as large chunks virtually unchanged from the swallowed pieces. We conclude that erythromycin accelerates gastric emptying at the expense of gastric sieving.

Animals↗
PubMed1996

Gastric myoelectric activity changes following open abdominal surgery in humans.

We examined the postoperative changes in fasting gastric myoelectric activity in 11 patients undergoing nongastric surgery (colon surgery) via celiotomy. Recordings were performed on postoperative days (POD) 1, 2, 3, 5, and 7+ (7-35) for 1-1.5 hr after overnight fasting. Patients had placement of bipolar seromuscular recording electrodes on the proximal (N = 9) and distal (N = 11) antrum at the time of surgery. Data were analyzed visually and analysis of variance or tests of proportion were used for statistical analysis. Although there was a trend of decreasing slow wave frequency from POD 1 to 7+ in the proximal and distal antrum, no significant differences were observed in slow wave amplitude or in the percentage of slow waves with spike activity between postoperative day. In a few of the patients, several types of gastric dysrhythmias were infrequently observed. We conclude that certain parameters of fasting gastric myoelectric activity do not change sufficiently following open abdominal surgery to adequately reflect clinical recovery from postoperative ileus.

Abdomen↗
PubMed1996

Effects of vection-induced motion sickness on gastric myoelectric activity and oral-cecal transit time.

The purpose of this study was to investigate the effects of vection-induced motion sickness on three cycle per minute gastric myoelectric activity and oral-cecal transit time. Forty-five subjects were exposed to a rotating optokinetic drum while electrogastrograms and subjective reports of symptoms were monitored. Prior to exposure, baseline breath hydrogen levels were established and subjects ingested vanilla pudding containing 10 g of lactulose. Breath hydrogen measurements were obtained before drum rotation and every 10 minutes after rotation, for 3 hr. Based on the severity of motion sickness symptoms reported, subjects were divided into two groups: a group susceptible to, and a group not susceptible to, vection-induced motion sickness. Averaged across subjects, the percentage of three cycle per minute activity decreased from baseline to rotation (3.6%) and from rotation to recovery (3.0%) [F(2/70)=2.43,P<0.1], with the susceptible group showing a greater overall decrease from baseline to recovery (8.9%), than the nonsusceptible group (4.2%) [F(1/35)=11.16,P<0.01]. The susceptible group had longer average oral-cecal transit times (144 min) than the nonsusceptible group (107 min) [t(36)=3.27,P<0.01]. Furthermore, symptom reports were positively correlated with oral-cecal transit times (r = 0.43, P < 0.05). In conclusion, vection-induced motion sickness is accompanied by decreased gastric three cycle per minute activity and prolonged oral-cecal transit times.

Adult↗
PubMed1995

Inhibitory effects of cholecystokinin on postprandial gastric myoelectrical activity.

While a number of studies have investigated the effects of cholecystokinin (CCK) on gastrointestinal motility, little is known on the effects of CCK on gastric myoelectrical activity, which regulates gastric motility. The aim of this study was to investigate the effects of intravenous infusion of CCK-8 on gastric myoelectrical activity in normal humans. Gastric myoelectrical activity was measured in 10 healthy subjects with a noninvasive electrogastrographic technique by placing abdominal electrodes on the epigastric area. Two study sessions were performed in each subject on two separate days with double-blinded infusion of either saline or CCK (24 pmol/kg/hr). The procedure for each session was as follows: (A) 30-min baseline fasting electrogastrogram (EGG); (B) start infusion, another 30-min EGG; (C) give meal, 60-min EGG; and (D) stop infusion, another 60-min EGG. The dominant frequency and peak power (amplitude) of the EGG, and the percentage of normal 2-4 cycles/min slow waves during each recording session were computed and compared between placebo and CCK. It was found that normal 3 cpm slow waves were recorded in all EGGs. Infusion of CCK had no effect on the frequency of the gastric slow wave and did not induce gastric dysrhythmias. It was also found that intravenous infusion of CCK significantly decreased the EGG peak power (amplitude) during the first hour after the meal (the infusion was given during this period) in comparison with placebo (P < 0.05). This inhibitory effect on EGG peak power was sustained but not significant during the second postprandial hour (the infusion was not given during this period). It was concluded that intravenous infusion of CCK at a physiological concentration significantly decreased the postprandial EGG amplitude in normal humans, suggesting an inhibitory effect on postprandial gastric motility, but did not change the frequency and regularity of the gastric slow wave.

Adult↗
PubMed2001

Circadian rhythm of rectal motor complexes.

PURPOSE: Prolonged rectal pressure recordings have revealed that the rectum exhibits typical bursts of regular pressure waves, also called rectal motor complexes. Although there is consensus regarding the characteristics of rectal motor complexes, their function is poorly understood. Furthermore, data regarding the circadian rhythm of these complexes are either lacking or conflicting. Therefore, we conducted a study to investigate the circadian rhythm of rectal motor complexes in fully ambulant subjects. Because a meal is a powerful and physiologic stimulus to elicit colonic pressure activity, we also studied the effect of a meal on these rectal motor complexes. METHODS: Prolonged ambulant anorectal pressure recordings were performed in 12 healthy volunteers (male:female ratio, 6:6; median age, 27 (range, 22-53) years). A total of 139 rectal motor complexes were observed in >300 hours of recording. RESULTS: All subjects exhibited rectal motor complexes during the daytime, whereas in five subjects, no rectal motor complexes were observed during sleep. The number of rectal motor complexes was significantly lower during sleep (diurnal vs. nocturnal, 8 vs. 1 per subject, P < 0.0001). Furthermore, the duration and peak amplitude of these nocturnal rectal motor complexes were significantly reduced. On the ambulant recordings, the subjects marked a total of 20 meals. During the first 2 hours after these meals, rectal motor complexes were noted in 65 percent of the cases. The postprandial frequency of rectal motor complexes was significantly higher than the overall frequency (2/hour vs. 0.4/hour, P = 0.004). CONCLUSIONS: These findings suggest that sleep results in a reduction of rectal motor activity, whereas a meal provides a stimulus for increased rectal motor activity in fully ambulant subjects.

Adult↗
PubMed1999

Ambulatory manometric recording of anorectal activity.

PURPOSE: Ambulatory anorectal manometry is usually analyzed by computer analysis only. An in-depth analysis with visual assessment of the recordings combined with computer analysis is presented. METHODS: Recordings of 20 to 24 hours in length were performed on ten healthy subjects. Spontaneous anal canal relaxations were analyzed and related to changes in rectal pressure and any reported rectal sensation. Pressure variations in the anorectum, including the rectal motor complex, were studied. RESULTS: In the awake subject the frequency of anal canal relaxations was 14.5 to 18.7/hour, and the frequency was 4.3/hour while asleep. They can be divided into two different subtypes. The amplitude of the pressure fall was 26 to 29 mm Hg, but diminished during sleep to 19 mm Hg. The duration of each relaxation was 16 to 19 seconds. Passage of flatus and the sensation of flatus in the rectum occurs 1.5 and 1.2 times per hour, respectively, usually with simultaneous anal canal relaxation. The frequency of rectal motor complexes in the midrectum was 0.4/hour and in the lower rectum was 0.7/hour; the duration was 10.3 and 5.8 minutes, respectively, with no nocturnal variation. The complexes could not be related to anorectal events. CONCLUSIONS: The study provides supplementary knowledge of anorectal physiology, particularly of anal canal relaxation, and proposes a more detailed method for evaluation of data obtained by ambulatory anorectal manometry.

Adult↗
PubMed1998

Nifedipine and verapamil inhibit the sigmoid colon myoelectric response to eating in healthy volunteers.

BACKGROUND: Constipation is not an infrequent side effect complained of by patients taking calcium channel blockers. This effect may reduce patients' compliance and yield potentially serious consequences. However, the underlying mechanisms for constipation caused by such compounds are not known. AIMS: The purpose of the present study was to assess the effects of nifedipine and verapamil on the sigmoid myoelectric response to eating, a physiologic test of colonic motor function. SUBJECTS AND METHODS: Nine healthy male volunteers with no previous abdominal surgery were recruited for the study and underwent three paired studies at two-week intervals. Myoelectric sigmoid activity was recorded by means of two clip electrodes introduced within the viscus without preparation for 30 minutes basally and 90 minutes postprandially. Each study was preceded by placebo, nifedipine (20 mg), or verapamil (120 mg). RESULTS: Analysis of the tracings revealed that nifedipine strongly inhibited the sigmoid myoelectric response to the meal. This response was also significantly reduced in those taking verapamil compared with the placebo group, although to a much lesser extent than in those taking nifedipine. CONCLUSIONS: We conclude that constipation as a result of some calcium channel blockers may be caused by inhibition of colonic motor activity by nifedipine and, to a lesser extent, by verapamil. The latter compound probably displays other mechanisms (reduced colonic transit, increased water absorption) also responsible for this side effect.

Adult↗
PubMed2001

Reversible autonomic dysfunction in hyperthyroid patients affects gastric myoelectrical activity and emptying.

The autonomic nervous system (ANS) function in hyperthyroidism has been so far investigated mainly from the cardiovascular point of view. The aim of this study is to show that the ANS dysfunction in hyperthyroidism is also expressed in gastric myoelectrical activity disturbances and gastric emptying disorders and to search for a correlation between the severity of clinical manifestation and free thyroid hormone levels and the degree of the ANS dysfunction. The analyzed group included 50 recently diagnosed patients with hyperthyroidism who were examined twice: before and after 3 months of thyrostatic treatment. Results were compared with those of a sex-, age- and BMI-matched control group of 50 healthy volunteers. The study included: heart rate variability analysis in time and frequency domain, at rest and during a deep-breathing test, surface electrogastrography in preprandial and postprandial periods measured simultaneously with the ultrasound assessment of gastric emptying time by Bolondi method. In patients with hyperthyroidism in comparison with the control group, the following significant differences were observed: a sharp reduction of the high-frequency component and a decrease of heart rate variability, a high incidence of dysrhythmia with dominant bradyarrhythmia, and a delay of gastric emptying. The degree of disorders related to the degree of clinical manifestation of hyperthyroidism's symptoms and free triiodothyronine serum concentration both. All the disorders were functional and disappeared in a stable euthyroidism. To conclude, the ANS dysfunction in hyperthyroidism results not only in withdrawal of vagal inhibitory effect on sinoatrial node, but in impaired mutual neuro-hormonal regulation (decrease of vagal influence) of gastric myoelectrical activity followed by delay of gastric emptying.

Adult↗
PubMed1994

Modulation of pumping function of gastric body and antropyloric contractions.

Gastric and antropyloric phasic contractions control transpyloric pulsatile flow, the major mechanism of gastric emptying. Both the occurrence and patterning of phasic gastric contractions are highly modulated by intestinal feedback mechanisms, with resultant variation in gastric emptying. The observed patterns of these contractions can only be plausibly explained by the action of neural influences on gastric motility. These influences derive from several mechanisms driven by intestinal feedback, central nervous system controls, and higher centers, with transmission of signals via intrinsic enteric pathways and extrinsic nerves. It is suggested that the occurrence and patterning of gastric phasic contractions depend on the spatial specificity and local modulation of the intensity of neural stimulation of gastric muscle. The resultant strength of contraction determines the occurrence and timing of lumen occlusion relative to adjacent regions. The timing of lumen occlusion in adjacent regions may be the major determinant of mechanical outcome.

Animals↗
PubMed2004

Mechanisms of action of the implantable gastric stimulator for obesity.

An implantable gastric stimulator (IGS(R)) has been used for the treatment of obesity with promising results. However, possible mechanisms involved with the treatment of obesity using an IGS are not well understood. According to recent clinical and basic studies, it seems that an IGS reduces appetite and increases satiety, attributed to its inhibitory effects on gastric motility and its direct effects on the central nervous system and hormones related to satiety and/or appetite. It has been indicated that chronic gastric stimulation impairs intrinsic gastric myoelectrical activity in the fed state, induces gastric distention in the fasting state and inhibits postprandial antral contractions. The impairment of gastric myoelectrical activity and contractions is associated with impaired digestion and emptying of the stomach, which may lead to early satiety and reduced food intake. The induction of gastric distention in the fasting state results in activation of stretch receptors, causing satiety. It has also been shown that an IGS may have direct regulatory effects on the central nervous system and certain hormones. Modulation of neuronal activities and release of certain hormones with an IGS may also explain the reduction of appetite and the increase of satiety.

Central Nervous System↗
PubMed2006

The effect of stress on absorption of acetaminophen.

RATIONALE: There is a large variability in the response to pharmacological treatment. Some studies have linked this variability to stress levels, i.e., stress may slow and/or reduce absorption of drugs. OBJECTIVES: The present experiment investigated the hypothesis that stress slows absorption of drugs. METHODS: Twenty-four volunteers participated in a within-subjects design with three conditions, each lasting 70 min. Subjects watched a movie hypothesized to induce stress, subjects listened to music hypothesized to reduce stress, and in a control condition no stimuli were presented. Each condition was spaced 2 days or more apart. In each condition, subjects received 500 mg oral acetaminophen. Measures of stress and acetaminophen levels were obtained every 10 min. RESULTS: Indices of subjective stress and arousal and cortisol, were increased during the movie compared to control. Subjective arousal and cortisol were decreased during music compared to control. However, acetaminophen levels were the same across time in all three experimental conditions. CONCLUSIONS: There was no effect of the experimental manipulations on acetaminophen absorption, indicating that stress was not related to drug absorption. However, stress could play a role in other processes related to drug pharmacokinetics.

Acetaminophen↗
PubMed2004

The herbal medicine Rikkunshi-to stimulates and coordinates the gastric myoelectric activity in post-operative dyspeptic children after gastrointestinal surgery.

Rikkunshi-to (TJ-43), a gastroprotective herbal medicine, has been used for the symptomatic relief of adult patients with dyspepsia. However, its mechanism has yet to be fully elucidated. The aim of this study is to evaluate the effect of TJ-43 on the gastric myoelectric activity in post-operative dyspeptic patients, whose symptoms persisted for over 1 year after gastrointestinal surgery. Electrogastrography (EGG) recordings were performed to calculate the biomechanical parameters on the dominant peak frequency (DPF). Eight pediatric patients with dyspeptic symptoms after gastrointestinal surgery were examined and six age-matched children without any dyspeptic symptoms were used as controls, and they were compared with nine age-matched children without any dyspeptic symptoms after gastrointestinal surgery as subcontrols. All patients exhibited symptomatic relief after the administration of TJ-43, and the mean symptom score decreased significantly after the treatment of TJ-43 over a 1-month period ( P<0.0001). The variability index (VI) and the percentage of normal waves (PNW) were calculated as irregularity parameters of DPF. The power ratio (PR) was calculated as a parameter of the gastric contractile activity. There were no significant differences in the VI and PNW between the controls and patients during the postprandial state after therapy, even though significant differences existed regarding those parameters between the controls and patients before the therapy. There were no significant differences in the DPF, VI, and PNW between the controls and subcontrols. Furthermore, PR exhibited a significant increase after therapy ( P<0.05). However, there was a significant difference in the PR between the controls and subcontrols ( P<0.05). Postprandial dip was observed in all control subjects, eight patients in the subcontrols, and two patients after administration of TJ-43, respectively. An abnormal gastric electrical activity therefore seems to be an important factor in the pathophysiology of post-operative dyspeptic children. The coordinating and stimulating effect of TJ-43 on the gastric myoelectric activity therefore seems to play an important role in the reduction of dyspeptic symptoms.

Adolescent↗
PubMed2004

A disturbance of the gastric myoelectric activity in post-operative patients with biliary atresia.

BACKGROUND: Abnormalities in gastrointestinal motility have been reported in adult patients with advanced liver disease. However, there have so far been no reports on the gastric myoelectric activity in post-operative patients with biliary atresia (BA). AIM: The purpose of this study was to evaluate the gastric myoelectric activity in post-operative patients with BA in relation to liver fibrosis. PATIENTS AND METHODS: Twenty-one post-operative patients with BA, consisting of 6 boys and 15 girls with a mean age of 8.0 years and 6 healthy children (control group) were included in the study. The gastric myoelectric activity was measured by electrogastrography (EGG). The patients with BA were divided into two groups according to the serum hyaluronic acid (HA) level as a marker of liver fibrosis: the fibrotic group (FG, n=11), HA>50 ng/ml and the non-fibrotic group (NF, n=10), HA <==50 ng/ml. All recorded data were spectrally analyzed and any parameters related to changes in the dominant peak frequency (DPF) and its power were investigated. Furthermore, the gastrointestinal symptom scores (GSS) were calculated in patients with dyspeptic symptoms according to the degree of advanced liver fibrosis. RESULTS: The results showed that 1) the postprandial DPF in the FG tended to be higher than that in the NFG ( p=0.051), 2) the postprandial variability index of the DPF in the FG and NFG were significantly higher than those in the controls ( p<0.05), and 3) the preprandial percentage of normal waves (PNW) in the FG tended to be lower than that in the controls ( p=0.089). The postprandial PNWs in the FG and NFG were significantly lower than those in the controls ( p<0.05). Especially, the postprandial PNW in the FG was significantly lower than that in the NFG ( p<0.05). 4) The power ratio in the FG and NFG were significantly lower than those in the controls ( p<0.05), and 5) the GSSs in the FG were significantly higher than those in the NFG ( p<0.05). CONCLUSIONS: The gastric myoelectric activity appeared to be disturbed in BA patients associated with portal hypertension and neurohormonal changes due to liver fibrosis.

Adolescent↗
PubMed2004

Effect of single-dose administration of recombinant interferon-alpha2b on gastric myoelectrical activity in patients with chronic hepatitis C.

BACKGROUND: Upper abdominal complaints during interferon therapy may result from impaired gastric motility and/or evacuatory function. We examined the effect of acute administration of interferon on gastric myoelectrical activity (GMA) with the use of surface electrogastrography. METHODS: The study population comprised 25 patients with chronic hepatitis C. All of them were naive to interferon. On 2 days, after a 25-min basal GMA registration, in group A (5 men, 7 women, aged 44.3 +/- 2.8 years) placebo or 5 million i.u. recombinant interferon alpha-2b (IFNA) was administered s.c. and the GMA was recorded in the interdigestive state for two periods (2 h and 4 h), separated by a 15-min break. In group B (7 men, 6 women, aged 44.7 +/- 3.9 years) placebo or 5 million i.u. IFNA was injected s.c. after the ingestion of a semiliquid test meal of 364 kcal. Subsequently, the postprandial GMA was recorded for two periods (2 h and 4 h), separated by a 15-min break. RESULTS: A typical flu-like syndrome was observed in 91.7% of patients in group A, and in 92.3% of patients in group B, thus providing evidence of the pharmacodynamic efficiency of the IFNA administration. In the fasted state, IFNA brought about a negligible increase in the rhythmicity and power of the gastric slow waves. IFNA did not elicit any statistically significant effect on gastric slow-wave activity postprandially. CONCLUSIONS: Acute administration of interferon does not involve any deterioration of GMA that could be linked to the previously reported upper abdominal symptoms in patients undergoing treatment with this drug.

Adult↗