Gastric dysrhythmias and nausea of pregnancy

Effects of Banxia Xiexin Decoction on apoptosis of interstitial cells of cajal by regulation of MiR-451-5p: An in vivo and in vitro study

ETHNOPHARMACOLOGICAL RELEVANCE

Banxia Xiexin Decoction (BXD) is a traditional Chinese medical formula applied to gastrointestinal (GI) motility disorders. Previous studies showed that miR-451-5p was down-regulated in rats with GI motility disorders induced by gastric electrical dysrhythmia. Interstitial cells of cajal (ICCs) are pacemakers for GI motility, while loss of ICCs is responsible for GI motility disturbance. Thus, the underlying interaction mechanisms for BXD regulating ICCs apoptosis via miR-451-5p remain to be explored.

AIM OF THE STUDY

In this work, the main objectives were to examine the efficacy of BXD on ICCs via miR-451-5p both in GI motility disorders rats model and in vitro, as well as the potential contributions of SCF/c-kit signaling.

MATERIALS AND METHODS

Rats with gastric electrical dysrhythmia were established in male SD rats by using a single-day diet and a double fasting method (drinking diluted hydrochloric acid water during the period) for 4 weeks. The gastric slow wave (GSW) recording, RT-qPCR, and western blot were performed to examine the effects of BXD on ICCs apoptosis in rats with GED and miR-451-5p expression. In vitro assays included CCK-8, flow cytometry analysis, RT-qPCR, and western blot were applied to investigate the potential molecular mechanism of BXD on ICCs apoptosis via miR-451-5p.

RESULTS

BXD promoted gastric motility, reduced ICCs apoptosis, and elevated miR-451-5p in GED rats. In addition, miR-451-5p was significantly up-regulated in ICCs after BXD treatment compared with that in ICCs with miR-451-5p inhibitor transfection. Meanwhile, high miR-451-5p expression with either BXD treatment or miRNA mimics enhanced ICCs proliferation and inhibit apoptosis. Moreover, overexpression of miR-451-5p can reverse G0/G1 arrest in ICCs by BXD treatment. Further, SCF and c-kit protein levels were detected to demonstrate that modulation of miR-451-5p by BXD treatment was involved in this signaling.

CONCLUSIONS

Through this study, we demonstrated that BXD could promote ICCs proliferation and inhibit apoptosis via miR-451-5p and may involve the modulations of SCF/c-kit signaling, thus suggesting a new therapy basis for GI motility dysfunction from the perspective of modulation of ICCs apoptosis by targeting miR-451-5p.

Gastroparesis in pregnancy

Gastroparesis is a functional gastrointestinal disorder that more commonly affects women, with most cases being diagnosed during childbearing age. However, there is a paucity of data and guidelines to specifically highlight the epidemiology, disease course, maternal and fetal impact, and the management of existing gastroparesis during pregnancy. Apart from metoclopramide, there is no approved therapy specifically indicated for gastroparesis. More importantly, pregnant and breastfeeding women are excluded from clinical trials evaluating pharmacologic agents in the management of gastroparesis. This poses a real challenge to healthcare providers in counseling and managing patients with gastroparesis. In this systematic review, we summarize the current available literature and the knowledge gaps in the impact of pregnancy on gastroparesis and vice versa. We also highlight the efficacy and safety profiles of available pharmacologic and nonpharmacologic therapies in the management of patients with gastroparesis, with emphasis on judicious use of dietary approaches that are deemed relatively safe during pregnancy.

Emerging Progress in Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum: Challenges and Opportunities

Nausea and vomiting of pregnancy (NVP) is a common condition that affects up to 70% of pregnant women. Hyperemesis gravidarum (HG) is considered the serious form of NVP, which is reported in 0.3–10.8% of pregnant women. NVP has a relatively benign course, but HG can be linked with some poor maternal, fetal, and offspring outcomes. The exact causes of NVP and HG are unknown, but various factors have been hypothesized to be associated with pathogenesis. With the advance of precision medicine and molecular biology, some genetic factors such as growth/differentiation factor 15 (GDF15) have become therapeutic targets. In our review, we summarize the historical hypotheses of the pathogenesis of NVP and HG including hormonal factors, Helicobacter pylori, gastrointestinal dysmotility, placenta-related factors, psychosocial factors, and new factors identified by genetics. We also highlight some approaches to the management of NVP and HG, including pharmacological treatment, complementary treatment, and some supporting treatments. Looking to the future, progress in understanding NVP and HG may reduce the adverse outcomes and improve the maternal quality of life during pregnancy.

Gastric interoception and gastric myoelectrical activity in bulimia nervosa and binge-eating disorder

OBJECTIVE

Identifying factors that control food intake is crucial to the understanding and treatment of eating disorders characterized by binge eating. In healthy individuals, stomach distension plays an important role in the development of satiation, but gastric sensations might be overridden in binge eating. The present study investigated the perception of gastric signals (i.e., gastric interoception) and gastric motility in patients experiencing binge-eating episodes, that is, bulimia nervosa (BN) and binge-eating disorder (BED).

METHOD

Twenty-nine patients with BN or BED (ED group) and 32 age-, sex-, and BMI-matched healthy controls (HC group) participated in the study. The onset of satiation and stomach fullness were assessed using a novel 2-step water load test (WLT-II). Gastric myoelectrical activity (GMA) was measured by electrogastrography (EGG) before and after ingestion of noncaloric water.

RESULTS

Individuals in the ED group drank significantly more water until reporting satiation during the WLT-II. The percentage of normal gastric myoelectrical power was significantly smaller in the ED group compared to HC, and negatively related to the number of objective binge-eating episodes per week in patients with BN or BED. Power in the bradygastria range was greater in ED than in HC participants.

DISCUSSION

Patients with EDs have a delayed response to satiation compared to HC participants, together with abnormal GMA. Repeated binge-eating episodes may induce disturbances to gastric motor function.

TRANSCUTANEOUS MULTICHANNEL ELECTROGASTROGRAPHY: NORMAL PARAMETERS IN A BRAZILIAN POPULATION

BACKGROUND

Electrogastrography (EGG) is a noninvasive technique for the assessment of gastric myoelectrical activity using electrodes placed on the abdominal surface. Changes in gastric myoelectrical activity may be associated with diseases such as gastroparesis, functional dyspepsia, nausea, and recurrent vomiting. In Brazil, no studies to date have assessed gastric myoelectrical activity using multichannel EGG in healthy individuals.

OBJECTIVE

To establish normal values of transcutaneous multichannel EGG in healthy Brazilian individuals.

METHODS

This was a prospective study including 20 healthy individuals who underwent EGG. Recording was performed during two periods: a preprandial recording was performed for 30 minutes, and a postprandial recording was performed for 30 minutes after a soft-solid meal of 400 kcal (20 grams of proteins, 60 grams of carbohydrates, and 9 grams of fat).

RESULTS

We assessed dominant frequency (DF) parameters, %DF distribution, the instability coefficient, and the power ratio (PR). A total of 20 individuals (11 women and 9 men) with a mean age of 39.5±7.4 years were included. Mean DF (95%CI) ranged from 2.4 to 3.1 cpm in the resting phase and 2.6 to 3.2 cpm in the postprandial period. The %DF in normogastria range was >70% in all healthy individuals. We identified that only one individual did not present a positive response to the test meal, and the other 19 individuals showed a PR greater than 1. The instability coefficient did not change significantly with meal intake.

CONCLUSION

Multichannel EGG may be applied in future studies to evaluate gastric motility disorders in the Brazilian population.

Gastric myoelectrical and neurohormonal changes associated with nausea during tilt-induced syncope

BACKGROUND

Nausea is a common prodromal symptom of neurally mediated syncope, but the biological factors linking nausea with syncope have not been studied. We aimed to characterize nausea during tilt-induced syncope by exploring related changes in gastric myoelectrical activity and plasma epinephrine, norepinephrine, and vasopressin concentrations across study phases of recumbency, tilt, syncope, and recovery.

METHODS

Electrogastrographic and plasma hormone changes were compared between patients with tilt-induced syncope and nausea (n = 18) and control subjects (n = 6) without symptoms or hemodynamic changes during tilt-table testing.

KEY RESULTS

Over a 4-minute period preceding syncope, sequential electrogastrography epochs demonstrated an increase over time in bradygastria (P = .003) and tachygastria (P = .014) power ratios, while the dominant frequency (P < .001) and the percent normogastria (P = .004) decreased. Syncope led to significant differences between cases and controls in electrogastrographic power ratios in each frequency range: bradygastria (P = .001), tachygastria (P = .005), and normogastria (P = .03). Nausea always followed electrogastrographic changes, and nausea resolution always preceded electrogastrographic normalization. Plasma vasopressin (676.5 ± 122.8 vs 91.2 ± 15.3 pg/mL, P = .012) and epinephrine (434 ± 91.3 vs 48.7 ± 2.5 pg/mL, P = .03), but not norepinephrine (P > .05), also differed with syncope between cases and controls.

CONCLUSIONS AND INFERENCES

The nausea related to tilt-induced syncope is temporally associated with changes in gastric myoelectrical activity and increases in plasma vasopressin and epinephrine. The biological mechanisms that induce syncope are physiologically distinct from other experimental models of nausea such as illusory self-motion, yet nausea with syncope appears to have similarly associated electrogastrographic and hormone changes. Thus, tilt-induced syncope could serve as an informative experimental model for nausea research.

Progress in Mathematical Modeling of Gastrointestinal Slow Wave Abnormalities

Gastrointestinal (GI) motility is regulated in part by electrophysiological events called slow waves, which are generated by the interstitial cells of Cajal (ICC). Slow waves propagate by a process of "entrainment," which occurs over a decreasing gradient of intrinsic frequencies in the antegrade direction across much of the GI tract. Abnormal initiation and conduction of slow waves have been demonstrated in, and linked to, a number of GI motility disorders. A range of mathematical models have been developed to study abnormal slow waves and applied to propose novel methods for non-invasive detection and therapy. This review provides a general outline of GI slow wave abnormalities and their recent classification using multi-electrode (high-resolution) mapping methods, with a particular emphasis on the spatial patterns of these abnormal activities. The recently-developed mathematical models are introduced in order of their biophysical scale from cellular to whole-organ levels. The modeling techniques, main findings from the simulations, and potential future directions arising from notable studies are discussed.

Autonomic dysfunction of gastric motility in major depression

BACKGROUND

Patients suffering from major depressive disorder (MDD) often complain about somatic symptoms. Cardiac complaints have been examined predominantly. However, gastrointestinal complaints are also reported frequently and are associated with worse outcomes. The research concerning changes in gastric motility of these patients is rather sparse. The aim of our study was to determine dysfunction of gastric motility and gastrointestinal symptoms in MDD. The duration and severity of MDD were examined regarding its influence over gastric emptying.

METHODS

Gastric emptying was determined by a ¹³C-acetate breath test in patients with MDD (n = 29) and healthy control subjects (n = 51). Prior to this, depressive illness was operationalized using external and self-assessment scales (HAMD-21, MADRS, BDI, CGI). Whether the severity or duration of MDD influenced the gastric emptying parameters was examined using Spearman's correlation. In addition, autonomic complaints were recorded by means of an ANS score. Each ANS score item was determined using a Mann-Whitney U or Kruskal-Wallis test concerning the gastric emptying parameters.

RESULTS

There was a significant difference in the parameters of the maximum gastric emptying rate (T_max) and gastric half emptying time T_1/2b between patients with MDD and healthy control subjects (T_max 66.21min vs 53.35min, p < 0.006, T_1/2b 207.59min vs 133.27min, p < 0.005). There was a significant negative correlation between T_max and the severity of MDD determined with the depression rating scales BDI (Spearman's rank - 0.521, p = 0.013) and HAMD-21 (r - 0.384, p = 0.048). No correlation was found between the duration of MDD and the maximum gastric emptying rate (r - 0.125, p = 0.519) and gastric half emptying time (r - 0.62, p = 0.749).

CONCLUSION

Gastrointestinal motility is significantly impaired in patients with MDD compared to healthy control subjects. Autonomic complaints were indicated frequently in MDD patients. The duration of MDD had no influence over the time of gastric emptying. There was a significant negative correlation between the severity of MDD and T_max, indicating that the T_max was reached earlier with the progression of MDD. The slowing of gastric motility in MDD patients is likely a result of a dysfunction of the autonomic nervous system.

Depression and anxiety disorder in hyperemesis gravidarum: A prospective case-control study

Objective

To assess the anxiety and depression status of women with hyperemesis gravidarum (HG); the risk factors for developing both depression and anxiety in women with HG were evaluated.

Materials and Methods

A total of 200 women, 100 diagnosed as having HG before the 20th week of gestation at a tertiary referral center and 100 gestational-age-matched controls were enrolled. The socio-demographic data and the depression and anxiety scores, as assessed using the Beck depression and anxiety inventory were compared between the two groups.

Results

The median depression and anxiety scores were significantly higher in the HG group compared with controls (19.5 vs. 9.0 and 22.0 vs. 10.0). Women with HG have the highest relative risks for moderate depression and severe anxiety [relative risk (RR): 16.88 and RR: 20.50, respectively]. In the univariate analysis, having HG, low education level, low income and poor social relationships were significant predictors of depression and having HG. Moreover, poor social relationships significantly predicted the presence of anxiety disorder. However, having HG and poor social relationships were found as the only independent predictors of both depression and anxiety. Patients with HG were 5.5 and 6.7 times more prone to having depression and anxiety disorder compared with controls, respectively.

Conclusion

Both depression and anxiety disorder were more frequent in women with HG who have weak family and social relationships, lower education and income levels. Therefore, the determination of the psychological status of women with HG should be an integral part of the evaluation.

Gastric myoelectric activity during cisplatin-induced acute and delayed emesis reveals a temporal impairment of slow waves in ferrets: effects not reversed by the GLP-1 receptor antagonist, exendin (9-39)

Preclinical studies show that the glucagon-like peptide-1 (GLP-1) receptor antagonist, exendin (9-39), can reduce acute emesis induced by cisplatin. In the present study, we investigate the effect of exendin (9-39) (100 nmol/24 h, i.c.v), on cisplatin (5 mg/kg, i.p.)-induced acute and delayed emesis and changes indicative of ‘nausea’ in ferrets. Cisplatin induced 37.2 ± 2.3 and 59.0 ± 7.7 retches + vomits during the 0-24 (acute) and 24-72 h (delayed) periods, respectively. Cisplatin also increased (P<0.05) the dominant frequency of gastric myoelectric activity from 9.4 ± 0.1 to 10.4 ± 0.41 cpm and decreased the dominant power (DP) during acute emesis; there was a reduction in the % power of normogastria and an increase in the % power of tachygastria; food and water intake was reduced. DP decreased further during delayed emesis, where normogastria predominated. Advanced multifractal detrended fluctuation analysis revealed that the slow wave signal shape became more simplistic during delayed emesis. Cisplatin did not affect blood pressure (BP), but transiently increased heart rate, and decreased heart rate variability (HRV) during acute emesis; HRV spectral analysis indicated a shift to ‘sympathetic dominance’. A hyperthermic response was seen during acute emesis, but hypothermia occurred during delayed emesis and there was also a decrease in HR. Exendin (9-39) did not improve feeding and drinking but reduced cisplatin-induced acute emesis by ~59 % (P<0.05) and antagonised the hypothermic response (P<0.05); systolic, diastolic and mean arterial BP increased during the delayed phase. In conclusion, blocking GLP-1 receptors in the brain reduces cisplatin-induced acute but not delayed emesis. Restoring power and structure to slow waves may represent a novel approach to treat the side effects of chemotherapy.

Nausea and vomiting of pregnancy - What's new?

Nausea and vomiting of pregnancy (NVP) is one of the most common disorders of pregnancy. The symptoms occur predominantly during the first trimester, although in a subgroup of patients they can continue throughout the entire pregnancy and can affect the woman's quality of life. A small percentage of women develop a severe form of NVP called hyperemesis gravidarum (HG) that if left untreated may lead to significant maternal morbidity and adverse birth outcomes. Overall, the morbidity in pregnant women with NVP is significant, although it tends to be underestimated. The pathogenesis of NVP remains unclear, but there is consensus that the disorder is multifactorial and that various genetic, endocrine and infectious factors may be involved. The treatment of NVP can be challenging as the optimal targets for therapy are not known. Currently, the therapy used depends on the severity of the disorder and it is focused on improving the symptoms while minimizing risks to mother and fetus. Therapies range from dietary changes, pharmacologic treatment or hospitalization with intravenous fluid replacement and nutrition therapy. The aims of this review are 1) to provide an overview of NVP, 2) to present possible links between the most important factors associated with the pathogenesis of NVP and 3) to discuss the effectiveness and safety of the pharmacologic and non-pharmacologic options available to treat this disorder.

Lipase Supplementation before a High-Fat Meal Reduces Perceptions of Fullness in Healthy Subjects

Background/Aims

Postprandial symptoms of fullness and abdominal discomfort are common after fatty meals. Gastric lipases hydrolyze 10% to 20% of dietary triglycerides during the stomach trituration period of digestion. The aim of this study was to evaluate the effects of acid-resistant lipase on upper gastrointestinal symptoms, including fullness and bloating, as well as on gastric myoelectrical activity after healthy subjects ingested a high-fat, liquid meal.

Methods

This study utilized a double-blind, placebo-controlled, crossover design with 16 healthy volunteers who ingested either a capsule containing 280 mg of acid-resistant lipase or a placebo immediately before a fatty meal (355 calories, 55% fat). Participants rated their stomach fullness, bloating, and nausea before and at timed intervals for 60 minutes after the meal. Electrogastrograms were obtained to assess the gastric myoelectrical activity.

Results

Stomach fullness, bloating, and nausea increased significantly 10 minutes after ingestion of the fatty meal (p<0.01), whereas normal gastric myoelectrical activity decreased and tachygastria increased (p<0.05). With lipase, reports of stomach fullness were significantly lower compared with placebo (p<0.05), but no effect on gastric myoelectrical activity or other upper gastrointestinal symptoms was observed.

Conclusions

The high-fat meal induced transient fullness, bloating, nausea, and tachygastria in healthy individuals, consistent with post-prandial distress syndrome. Acid-resistant lipase supplementation significantly decreased stomach fullness.

Recent progress in gastric arrhythmia: pathophysiology, clinical significance and future horizons

Gastric arrhythmia continues to be of uncertain diagnostic and therapeutic significance. However, recent progress has been substantial, with technical advances, theoretical insights and experimental discoveries offering new translational opportunities. The discoveries that interstitial cells of Cajal (ICC) generate slow waves and that ICC defects are associated with dysmotility have reinvigorated gastric arrhythmia research. Increasing evidence now suggests that ICC depletion and damage, network disruption and channelopathies may lead to aberrant slow wave initiation and conduction. Histological and high-resolution (HR) electrical mapping studies have now redefined the human 'gastric conduction system', providing an improved baseline for arrhythmia research. The application of HR mapping to arrhythmia has also generated important new insights into the spatiotemporal dynamics of arrhythmia onset and maintenance, resulting in the emergence of new provisional classification schemes. Meanwhile, the strong associations between gastric functional disorders and electrogastrography (EGG) abnormalities (e.g. in gastroparesis, unexplained nausea and vomiting and functional dyspepsia) continue to motivate deeper inquiries into the nature and causes of gastrointestinal arrhythmias. In future, technical progress in EGG methods, new HR mapping devices and software, wireless slow wave acquisition systems and improved gastric pacing devices may achieve validated applications in clinical practice. Neurohormonal factors in arrhythmogenesis also continue to be elucidated and a deepening understanding of these mechanisms may open opportunities for drug design for treating arrhythmias. However, for all translational goals, it remains to be seen whether arrhythmia can be corrected in a way that meaningfully improves organ function and symptoms in patients.

Disturbed release of cholecystokinin in pregnant women with hyperemesis gravidarum

AIMS

We aimed to investigate cholecystokinin (CCK) release in pregnant women with and without hyperemesis gravidarum (HG).

MATERIAL AND METHODS

In this case-control study including 40 pregnant women with HG and 40 women with healthy uncomplicated pregnancies, serum CCK levels in addition to hematological, biochemical and hormonal parameters were investigated.

RESULTS

Serum CCK values were found to be significantly lower in pregnant women with HG (P < 0.001). Additionally, while serum blood urea nitrogen and free thyroxine levels were significantly higher, sodium, potassium, and thyroid stimulating hormone levels were significantly lower in women with HG than in control women. No correlation was detected between CCK and other parameters like ketonuria and thyroid function tests.

CONCLUSIONS

CCK release has been found to be halved in pregnant women with HG, which supports the hypothesis that gastrointestinal motility is increased in pregnant women with HG. A causal effect remains to be confirmed.

Different patterns between mechanical and electrical activities: an approach to investigate gastric motility in a model of long-term diabetic rats

The relationship between time-courses of mechanical and electrical events in longstanding diabetes was investigated in rats. Magnetic markers and electrodes were surgically implanted in the gastric serosa of male rats. Simultaneous recordings were obtained by AC biosusceptometry, electromyography and electrogastrography one, three and six months after injections of saline (control) or alloxan (diabetic). Frequency and amplitude of contraction, abnormal rhythmic index and half-bandwidth were obtained (ANOVA P < 0.05). Antral hypomotility and gastric motility instability were observed in the signal waveform of diabetic rats at the three time points of study. The mean frequency (4.4 ± 0.4 cpm) was strictly similar, but the mechanical and electrical correlation was lowest for diabetics groups. Decreases in mechanical amplitude were observed for all diabetic groups compared with control; also the ranges of frequency were much wider in diabetes. The half-bandwidth increased since the first month in mechanical recordings and only after the third month in electrical. In diabetic animals, about 40% of gastric activity was abnormal (against 12% in control) and may reach 60% in the sixth month of mechanical recordings. The multi-instrumental approach showed a more substantial deterioration in mechanical activity and created an integrative view of gastric motility for longstanding diabetic model.

The role of vagal neurocircuits in the regulation of nausea and vomiting

Nausea and vomiting are among the most frequently occurring symptoms observed by clinicians. While advances have been made in understanding both the physiological as well as the neurophysiological pathways involved in nausea and vomiting, the final common pathway(s) for emesis have yet to be defined. Regardless of the difficulties in elucidating the precise neurocircuitry involved in nausea and vomiting, it has been accepted for over a century that the locus for these neurocircuits encompasses several structures within the medullary reticular formation of the hindbrain and that the role of vagal neurocircuits in particular are of critical importance. The afferent vagus nerve is responsible for relaying a vast amount of sensory information from thoracic and abdominal organs to the central nervous system. Neurons within the nucleus of the tractus solitarius not only receive these peripheral sensory inputs but have direct or indirect connections with several other hindbrain, midbrain and forebrain structures responsible for the co-ordination of the multiple organ systems. The efferent vagus nerve relays the integrated and co-ordinated output response to several peripheral organs responsible for emesis. The important role of both sensory and motor vagus nerves, and the available nature of peripheral vagal afferent and efferent nerve terminals, provides extensive and readily accessible targets for the development of drugs to combat nausea and vomiting.

Effects of professional support on nausea, vomiting, and quality of life during early pregnancy

The purpose of this study was to examine the effectiveness of a professional support (PS) intervention (including individualized health education and supportive phone calls) in reducing the severity of nausea and vomiting (NV) and improving the quality of life (QOL) of women in early pregnancy. An experimental pretest/posttest design with a control group was used. Participants were recruited from a regional teaching hospital in southern Taiwan. The women in the experimental group (n = 40) received the PS intervention, while those in the control group (n = 39) only received routine nursing care. Analysis of covariance and mixed models were used to compare the experimental and control groups while adjusting for covariates. The severity of NV and the perceived level of symptom distress were significantly lower in the experimental group than in the control group during weeks 2 and 4, and the women in the experimental group showed a significant improvement in their QOL in week 4 (p < .05). However, there was no significant difference between the two groups in body weight at week 4 (p = .501). These findings provide empirical evidence in support of the effectiveness of PS in reducing the severity of NV and improving QOL for women during early pregnancy. This intervention could be routinely applied in prenatal nursing health education. Future studies could apply the concept of PS to different populations and health issues.

Electrogastrography in adults and children: the strength, pitfalls, and clinical significance of the cutaneous recording of the gastric electrical activity

Cutaneous electrogastrography (EGG) is a non-invasive technique to record gastric myoelectrical activity from the abdominal surface. Although the recent rapid increase in the development of electrocardiography, EGG still suffers from several limitations. Currently, computer analysis of EGG provides few reliable parameters, such as frequency and the percentage of normal and altered slow wave activity (bradygastria and tachygastria). New EGG hardware and software, along with an appropriate arrangement of abdominal electrodes, could detect the coupling of the gastric slow wave from the EGG. At present, EGG does not diagnose a specific disease, but it puts in evidence stomach motor dysfunctions in different pathological conditions as gastroparesis and functional dyspepsia. Despite the current pitfalls of EGG, a multitasking diagnostic protocol could involve the EGG and the (13)C-breath testing for the evaluation of the gastric emptying time-along with validated gastrointestinal questionnaires and biochemical evaluations of the main gastrointestinal peptides-to identify dyspeptic subgroups. The present review tries to report the state of the art about the pathophysiological background of the gastric electrical activity, the recording and processing methodology of the EGG with particular attention to multichannel recording, and the possible clinical application of the EGG in adult and children.

Ghrelin, acylated ghrelin, leptin and PYY-3 levels in hyperemesis gravidarum

OBJECTIVE

To assess the serum levels of gut and adipocyte-derived metabolic hormones that control appetite, adipocity, weight gain and energy hemostasis, namely total ghrelin (TG), acylated ghrelin (AG), leptin and PYY-3 in hyperemesis gravidarum (HG).

METHODS

Plasma samples of 86 women in their first trimester pregnancies with HG (n = 30), morning sickness of pregnancy (MSP) (n = 34) and control (n = 22) groups were obtained. Serum levels of TG, AG, leptin and PYY-3 were compared between the groups, and the correlations with severity of symptoms using modified PUQE (Pregnancy Unique Quantification of Emesis) scoring, BMI, E2, hCG and TSH were calculated.

RESULTS

Levels of TG, AG, PYY-3 and the TG/leptin ratio were significantly higher in HG group compared to MSP and the control groups (p ≤ 0.017). AG/TG ratio was significantly lower in the HG group compared to both MSP and control groups (p ≤ 0.017). There were either weak or no significant statistical correlations between the gut and adipose-related hormones and the modified PUQE scores, BMI, E2, hCG and TSH.

CONCLUSION

Gut-derived metabolic hormones ghrelin, AG and PYY-3 may be involved in the HG pathophysiology.

Electrogastrography: methodology, validation and applications

Electrogastrography (EGG) is a non-invasive method for the measurement of gastric myoelectrical activity. It was first discovered in 1921 and popularized in 1990s. EGG is attractive because it is non-invasive. However, due to its non-invasive nature, there have also been controversies regarding validity and applications of EGG. The aim of this review is to discuss the methodologies, validation and applications of EGG. Pros and cons of EGG will also be discussed in detail. First, the gastric slow wave and its correlation with gastric motility are presented. The association between gastric dysrhythmia and impaired gastric motility is reviewed. Secondly the method for recording the electrogastrogram is presented in detail and pitfalls in the recording and analysis of EGG are discussed. Thirdly, findings reported in the literature demonstrating the accuracy of EGG in recording gastric slow waves and gastric dysrhythmia are reviewed and discussed. The correlation of the electrogastrogram with gastric contraction is carefully discussed. Finally, applications of EGG in a few major areas are reviewed.

Electrogastrography: methodology, validation and applications

Electrogastrography (EGG) is a non-invasive method for the measurement of gastric myoelectrical activity. It was first discovered in 1921 and popularized in 1990s. EGG is attractive because it is non-invasive. However, due to its non-invasive nature, there have also been controversies regarding validity and applications of EGG. The aim of this review is to discuss the methodologies, validation and applications of EGG. Pros and cons of EGG will also be discussed in detail. First, the gastric slow wave and its correlation with gastric motility are presented. The association between gastric dysrhythmia and impaired gastric motility is reviewed. Secondly the method for recording the electrogastrogram is presented in detail and pitfalls in the recording and analysis of EGG are discussed. Thirdly, findings reported in the literature demonstrating the accuracy of EGG in recording gastric slow waves and gastric dysrhythmia are reviewed and discussed. The correlation of the electrogastrogram with gastric contraction is carefully discussed. Finally, applications of EGG in a few major areas are reviewed.

The electrifying stomach

The stomach is electrified and subject to eurhythmic and dysrhythmic electrical events - much like the heart. The normal human slow wave ranges from 2.5 to 3.75 cycles per min (cpm), tachygastrias range from 3.75 cpm to 10.0 cpm and bradygastrias from .5 to 2.5 cpm, the gastric dysrhythmias of men and women. In this issue of Neurogastroenterology & Motility, O'Grady, et al. describe the gastric dysrhythmias of pigs in electrocardiology terms. Printed circuit boards (PCB) with multi-electrode arrays (160-192 electrodes) were attached to the stomach serosa. Gastric dysrhythmias occurred in eight of the 16 anesthetized pigs and were analysed by manually and by computer. The patterns of dysrhythmias were reminiscent of cardiac dysrhythmias: conduction blocks, ectopic foci, re-entrant wave fronts, premature and aberrant slow waves and regular and irregular tachygastrias. The authors suggest gastric dysrhythmias recorded in pigs may be relevant to human gastric dysrhythmias and electricity-based therapies. The categories of porcine gastric dysrhythmias may help to understand the spectrum of gastric dysrhythmias of men and women recorded over the past 25 years. Analogies between gastric and cardiac neuromuscular disorders are explored because Neurogastroenterology is evolving as a clinical and therapeutic field utilizing knowledge of gastric rhythmicity and electro-contractile events. Interstitial cells of Cajal are the pacemaker cells of the stomach and loss of cells or faulty circuitry appear to be key pathways to gastric dysrhythmias. Gastric electrophysiology (EP) labs, human and animal, are needed to test hypotheses and advance understanding of human gastric dysrhythmias and upper GI symptoms.

Nausea and vomiting of pregnancy

Nausea and vomiting are common experiences in pregnancy, affecting 70% to 80% of all pregnant women. Various metabolic and neuromuscular factors have been implicated in the pathogenesis of nausea and vomiting of pregnancy (NVP) and hyperemesis gravidarum (HG), an entity distinct from NVP. However, their exact cause is unknown. Consequently, treatment of NVP and HG can be difficult, as neither the optimal targets for treatment nor the full effects of potential treatments on the developing fetus are known. This article reviews the epidemiology, pathology, diagnosis, outcomes, and treatment of NVP and HG.

Gastroparesis in pregnancy: case report and literature review

Gastroparesis is a syndrome characterized by delayed gastric emptying in the absence of mechanical obstruction. The most common underlying aetiology is diabetes mellitus; however, many cases are idiopathic. Pregnancy per se is associated with gastrointestinal neuromuscular dysfunction; however, reports of gastroparesis arising during pregnancy are rare. We report a case of severe gastroparesis and proximal small bowel paresis presenting during pregnancy.

Cannabinoid-induced reduction in antral pacemaker frequency: a telemetric study in the ferret

BACKGROUND

The gastric myoelectric activity (GMA) is the electrical pacesetter potential, which drives gastric motility. Cannabinoids have broad-spectrum antiemetic and antinauseant activity. Paradoxically, they inhibit intestinal peristalsis and reduce gastric motility but their effect on GMA remains unknown.

METHODS

Ferrets were surgically implanted with radiotelemetry transmitters to record GMA, body temperature and heart rate. The effect of WIN 55,212-2 (1 mg kg(-1), i.p.), an agonist at the cannabinoid type 1 and 2 receptors was examined in conscious, unrestrained ferrets. WIN 55,212-2 was also compared to the anandamide upregulator URB 597 (5 mg kg(-1), i.p.) for a potential to modulate the emetic response and behavioral changes induced by apomorphine (0.25 mg kg(-1), s.c.).

KEY RESULTS

WIN 55,212-2 decreased GMA frequency (8.1 ± 0.4 cpm, compared to 9.6 ± 0.1 cpm in vehicle-treated animals, n = 6, P < 0.01). Apomorphine induced 9.0 ± 1.6 emetic episodes, WIN 55,212-2 inhibited the emetic response (3.3 ± 1.0 episodes, n = 6, P < 0.05) but URB 597 had no effect (9.0 ± 1.5 episodes). Apomorphine-induced hyperactivity in vehicle-treated animals (6.5 ± 3.6-16.6 ± 4.9 active behavior counts, n = 6, P < 0.01), which was reduced by WIN 55,212-2 (5.0 ± 1.5 counts, n = 6, P < 0.05).

CONCLUSIONS & INFERENCES

WIN 55,212-2 demonstrated clear antiemetic efficacy, which extends the broad-spectrum antiemetic efficacy of cannabinoids to dopamine receptor agonists in the ferret. Our results, however, suggest a more limited spectrum of action for URB 597. WIN 55,212-2 decreased the frequency of the antral electrical pacemaker, which reveals new insights into the mechanism regulating the decrease in motility induced by cannabinoids.

Telemetry in a motion-sickness model implicates the abdominal vagus in motion-induced gastric dysrhythmia

In humans, motion sickness is associated with disruption of normal gastric myoelectric activity, and it has been proposed that this results from an imbalance of autonomic nervous system activity. We used the established Suncus murinus (house musk shrew) model of motion-induced emesis to investigate the effect of horizontal motion on gastric myoelectric activity (recorded using telemetry) and the involvement of the abdominal vagi. Surgical vagotomy increased baseline dysrhythmia and reduced the dominant power of the gastric myoelectric signals. In response to motion, normal gastric myoelectric activity was reduced in sham-operated animals but not in vagotomized animals. Vagotomy, however, failed to affect motion-induced emesis. In conclusion, motion had a differential effect in sham-operated and vagotomized animals, which is consistent with the hypothesis that motion-induced dysrhythmia arises from an autonomic nervous system imbalance.

Adherence and tolerability of iron-containing prenatal multivitamins in pregnant women with pre-existing gastrointestinal conditions

Prenatal multivitamin supplements (PMS) are recommended during pregnancy. Suboptimal adherence in women experiencing gastrointestinal (GI) conditions is thought to be attributed to the high elemental iron content in PMS. This study sought to quantify adherence and tolerability of iron-containing PMS in women with pre-existing GI conditions by recruiting women who called the Motherisk Helpline. Women with (n = 36) and without (n = 166) pre-existing GI conditions were randomised to either PregVit (n = 106) or Orifer F (n = 96). Monthly follow-up interviews were conducted to assess pill intake and GI adverse effects associated with PMS. The results of our study suggest that with the use of small size and low dose iron PMS, women with pre-existing GI conditions do not experience (1) more GI adverse effects, (2) lower adherence than women with no such conditions, and (3) may experience less severe nausea and vomiting of pregnancy. Supplementing with small tablets of low dose iron PMS should be considered.

Prelabor rupture of membranes at term requiring labor induction - a feature of occult fetal cephalopelvic disproportion?

AIM

To examine the maternal and neonatal characteristics related to labor outcome following induction for prelabor rupture of membranes (PROM) after 37 weeks' gestation.

METHOD

All singleton pregnancies delivered following spontaneous or induced labor after 37 weeks in four years were analyzed. Patients with labor induction for PROM comprised the study group. Outcome of labor was analyzed according to gestational age at delivery.

RESULTS

Among the 13,505 patients in the entire cohort, 1710 (12.7%) had labor induction for PROM. These women were older and heavier, were more nulliparas and had more large-for-gestational age (LGA) infants, higher rates of instrumental and cesarean deliveries, and a shorter mean gestation, but no difference in height, mean birth weight, or incidence of male infants. Multiple logistic regression analysis confirmed that labor induction was a weak but significant independent factor for cesarean delivery (aOR 1.18, 95% CI: 1.01-1.38). The rates of cesarean delivery significantly correlated with gestational age at delivery for both LGA (P<0.001) and non-LGA (P<0.001) infants, together with significantly increased birth weight.

CONCLUSION

The results suggest that a likely explanation for the cesarean delivery following labor induction for PROM at term in our population is underlying cephalopelvic disproportion.

Methods for measurement of gastric motility

There is an array of tests available to measure gastric motility. Some tests measure end points, such as gastric emptying, that result from several different functions, whereas other tests are more specific and test only a single parameter, such as contractility. This article reviews the tests most commonly available in practice and research to evaluate in vivo the gastric functions of emptying, accommodation, contractility, and myoelectrical activity. The rationale for testing, the relative strengths and weaknesses of each test, and technical details are summarized. We also briefly indicate the applications and validations of the tests for use in experimental animal studies.

Hyperirritable stomach as a cause of nausea and vomiting: clinical and radiographic findings

OBJECTIVE

The purpose of our study was to characterize the clinical and radiographic features of the hyperirritable stomach and to determine if it is associated with extraintestinal causes of nausea and vomiting in the absence of gastric outlet obstruction, gastroparesis, or intestinal obstruction or ileus.

CONCLUSION

The hyperirritable stomach was characterized on barium studies in 15 patients by rapid emesis of ingested barium, a collapsed stomach with little or no retained debris or fluid, and normal emptying of residual barium into nondilated duodenum and proximal jejunum. Fourteen (93%) of these 15 patients had extraintestinal causes of nausea and vomiting, and 13 (93%) of 14 with clinical follow-up had marked improvement or resolution of symptoms after treatment. Radiologists therefore should evaluate the stomach and duodenum even after rapid emesis of ingested barium in patients with nausea and vomiting to differentiate a hyperirritable stomach from mechanical or functional gastrointestinal obstruction.

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.

Da-Cheng-Qi-Tang promotes the recovery of gastrointestinal motility after abdominal surgery in humans

In order to examine the effects of Da-Cheng-Qi-Tang (DCQT) on gastrointestinal motility functions after abdominal surgery in humans, 33 patients with abdominal surgeries and 36 patients with cholecystectomies were divided into the DCQT and the control groups at random. Electrogastrography (EGG) and gastroduodenojejunal manometry was performed and the levels of plasma motilin were measured by radioimmunoassay. The results were as follows: (1) on the day of surgery, the ratio of EGG normal frequency in the DCQT group was higher than in the control group (P=0.0016); (2) the power of EGG in the DCQT group was higher than in the control group on the second and third days after surgeries (P=0.0011 and P=0.0215, respectively); (3) the percentage of normal bowel peristalsis was significantly higher in the DCQT group than in the control group (P<0.01); and (4) in the DCQT group, the plasma motilin level reached its peak earlier than in the control group. Our results suggest that DCQT can increase plasma motilin, enhance gastrointestinal motility, improve gastric dysrythmia, and reduce gastroparesis after abdominal surgery.

The Influence of Taste Stimuli and Illumination on Electrogastrogram Measurements

An electrogastrogram (EGG) is considered to be an index to the autonomic nervous system of the digestive organs. In the present study, we attempted to clarify whether or not an EGG can be used to evaluate the influence of illumination, and what kinds of effect taste stimuli and illumination have on the autonomic nervous system. In this study, we used the ratio of the normal wave component of the EGG (EGG-NR: 2-4.5 cpm power/1-10 cpm power) and the amplitude of a normal wave (EGG-NI: integrated EGG of 2-4.5 cpm). Thirteen healthy males participated in 16 experimental conditions (4 lighting conditionsx4 taste stimuli). The four lighting conditions were set by combinations of illuminance levels of 200 and 1500 lx and color temperatures of 3000 and 7500 K. The four taste stimuli were sweet (glucose), salty (salt), sour (acetic acid), and bitter (quinine). The changes in EGG-NR and EGG-NI were compared for different taste conditions. The results showed that EGG-NI was not significantly affected by the different taste conditions. However, the main effect of taste on EGG-NR was significant: sweet and salty tastes were significantly higher than the bitter taste. EGG-NR and EGG-NI in different lighting conditions were also compared. The main effect of different color temperatures was also significant, but the illuminance level did not affect EGG-NR. EGG-NR increased significantly at the lower color temperature. On the other hand, EGG-NI significantly increased at the lower illuminance. These results suggest that parasympathetic nervous activity has a predominant effect on gastric activity in different lighting environments. Therefore, EGG measurements may be useful indicators for illumination environment studies.

Treatment Options for Nausea and Vomiting During Pregnancy

Nausea and vomiting, common symptoms during pregnancy, often are regarded as an unpleasant but normal part of pregnancy during the first and early second trimesters. Nausea and vomiting of pregnancy (NVP) occurs in approximately 75-80% of pregnant women. The exact etiology and pathogenesis of NVP are poorly understood and are most likely multifactorial. Some theories for the etiology of NVP are psychological predisposition, evolutionary adaptation, hormonal stimuli, and Helicobacter pylori infection. Treatment ranges from dietary and lifestyle changes to vitamins, antiemetics, and hospitalization for intravenous therapy. Treatment generally begins with nonpharmacologic interventions; if symptoms do not improve, drug therapy is added. Although NVP has been associated with a positive pregnancy outcome, the symptoms can significantly affect a woman's life, both personally and professionally. Given the substantial health care costs, as well as indirect costs, and the potential decrease in quality of life due to NVP, providers need to acknowledge the impact of NVP and provide appropriate treatment.

Experimental gastric dysrhythmias and its correlation with in vivo gastric muscle contractions

AIM: To study the direct correlation between gastric dysrhythmias and in vivo gastric muscle tone.

METHODS: Five healthy dogs were implanted with 4 pairs of electrodes along the greater curvature, with a strain gauge (SG) being sutured parallel to the distal electrodes (2 cm above the pylorus). Intravenous vasopressin was given to induce gastric dysrhythmia. The percentage of regular slow waves and SG energy were calculated.

RESULTS: (1) the regularity of gastric myoelectric activity (GMA) was reduced during and after infusion of vasopressin; (2) SG energy was significantly decreased during the infusion of vasopressin; (3) the decrease in SG energy was well correlated with the reduction in GMA regularity; (4) SG energy was negatively correlated with bradygastria and tachygastria.

CONCLUSION: Vasopressin inhibits gastric contractions and impairs gastric slow waves; gastric dysrhythmias are associated with the reduced antral muscle contractions, and are indicative of antral hypomotility.

Gastric electrical stimulation has an immediate antiemetic effect in patients with gastroparesis

BACKGROUND

Electrical stimulation has been successfully employed to treat diseases involving electro-pathology in the heart, skeletal muscles, and the brain, but not in the GI tract.

AIM

This study examined the clinical feasibility and efficacy of GES in treating patients with severe gastroparesis.

METHODS

Nausea, vomiting, GEA, and liquid and solid gastric emptying were monitored in eleven patients with refractory gastroparesis at baseline and after one week of continuous electrical stimulation administered at 12 cycles/min. Eight patients were subsequently implanted with permanent stimulation devices. Follow-up studies were conducted after 1, 3, 6, and 12 mo. of stimulation.

RESULTS

After one week of stimulation, patients' quantified symptoms of nausea and vomiting decreased significantly, and liquid emptying and GEA improved. This improvement was maintained over time in the patients who continued to receive stimulation. Emptying of solids showed progressive improvement that became significant after 3 mo. The three patients who did not receive stimulation after the trial period showed significantly higher symptoms at 12 mo.

CONCLUSION

This paper demonstrates that GES at a frequency of 12 cycles/min has an immediate antiemetic effect, followed by an improvement in disordered gastric emptying.

Therapeutic potentials of a novel method of dual-pulse gastric electrical stimulation for gastric dysrhythmia and symptoms of nausea and vomiting

BACKGROUND

The aims of this study were to investigate the effects and mechanisms of a novel method of gastric electrical stimulation on the prevention of vasopressin-induced emetic response and gastric dysrhythmias.

METHODS

Fifteen dogs (10 normal, 5 vagotomized) chronically implanted with gastric serosal electrodes were used in a 3-session study (vasopressin, vasopressin plus 2-channel stimulation [DCS], and vasopressin plus dual-pulse stimulation [DPS]).

RESULTS

Vasopressin induced gastric dysrhythmias and motion sickness-like symptoms (P < .05) and these effects were blocked partially with vagotomy. Both methods of DCS and DPS were capable of preventing vasopressin-induced gastric dysrhythmias (P < .05) and motion sickness-like symptoms (P < .05). The antiemetic effects of the proposed methods of DCS and DPS were abolished by vagotomy but their antidysrhythmic effects were not blocked by vagotomy.

CONCLUSIONS

DCS and DPS are able to reduce vasopressin-induced gastric dysrhythmia and symptoms of nausea and vomiting. The vagal pathway is involved in the antiemetic effect but not the antidysrhythmic effect of the proposed methods of stimulation.

Evaluation of the effects of mastication and swallowing on gastric motility using electrogastrography

OBJECTIVES

The influence of mastication and swallowing on gastric motor function was evaluated by electrogastrography (EGG) and abdominal ultrasonography.

METHODS

The subjects were 30 elderly patients with tubal feeding without mastication and swallowing (T group) and 30 elderly controls who processed food by mastication and swallowing (C group). Gastric motor function was percutaneously examined before and after the ingestion of 250 ml of a liquid diet using an electrogastrograph (NIPRO EGG, A and D, Tokyo, Japan). The cross-sectional area of the gastric antrum was measured at 1 and 30 min after the start of ingestion of the liquid diet by external ultrasonography of the abdomen, and the gastric excretion function was evaluated. Furthermore, the spectral analysis of heart rate variability was performed using Holter electrocardiograms before and after ingestion. The low frequency power (LF power, 0.04-0.15 Hz), high frequency power (HF power, 0.15-0.40 Hz), and the LF/HF ratio were determined.

RESULTS

The peak amplitude at 3 cycles per minute (cpm) was significantly increased after ingestion in the C and T groups (p<0.05), and the ratio of increase was significantly lower in the T group (p<0.05). The mean amplitude for the brady-gastria and tachy-gastria was significantly higher in the T group than in the C group (p<0.05). The gastric excretion function, as evaluated by external ultrasonography of the abdomen, was significantly lower in the T group than in the C group (p<0.05). An analysis of heart rate variability demonstrated that the HF power, a parameter of parasympathetic activity, after ingestion was significantly higher in the C group than in the T group (p<0.05). No changes in LF power or LF/HF ratio, parameters of sympathetic activity, were induced by ingestion in either the C or T groups.

CONCLUSIONS

The parasympathetic nerve dominantly controls gastric motor function, but autonomic nervous activity is reduced in patients who are unable to masticate and swallow food, resulting in adverse effects on gastric motor function and excretion function. Mastication and swallowing not only prepare food for passage from the oral cavity to the esophagus but are also important in terms of subsequent events that occur in stomach. It has been proposed that autonomic nervous activity might be involved in mastication and swallowing.

Sickness and satiety: physiological mechanisms underlying perceptions of nausea and stomach fullness

The pathophysiology of nausea and the physiological mechanisms underlying perceptions of stomach emptiness and fullness are not clearly understood, but several potentially important factors have been identified. Gastric dysrhythmias are believed to contribute to the subjective experience of nausea and may also be involved with perceptions of stomach emptiness, hunger, and even dyspepsia symptoms like bloating and early satiety. Normal gastric neuromuscular function is more evident in the absence of nausea and is also thought to be related to feelings of satiety or comfortable stomach fullness. Autonomic and endocrine influences may also play a critical role in the pathophysiology of nausea and abnormal perceptions of stomach emptiness or fullness. Achieving a better understanding of the gastric neuromuscular and neurohormonal influences on perceptions arising from the viscera may prove invaluable in the development of novel treatments for such conditions as unexplained nausea, functional dyspepsia, and obesity.

The role of electrogastrography and gastrointestinal hormones in chemotherapy-related dyspeptic symptoms

BACKGROUND

The aim of this study was to investigate the relationship among motility disorders, dyspeptic symptoms, and plasma levels of gastrointestinal hormones in cancer patients who were well controlled for post-chemotherapy emesis.

METHODS

Twenty-five cancer patients treated with standard dosages of antiemetics and chemotherapies completed the study. Gastrointestinal symptoms were investigated by detailed questionnaire and visual analog score. Motility was investigated by cutaneous electrogastrography, and by blood levels of gastrin, serotonin, vasopressin, and substance P, before and 7 days after chemotherapy.

RESULTS

Before chemotherapy, no patient complained of dyspeptic symptoms, and no differences in electrogastrography (EGG) or in circulating peptide levels were found between patients who developed dyspepsia and those who did not. After chemotherapy, 13 patients suffered from dysmotility-like symptoms (total symptom score, 11.5 [2.5-37.9]; median value and 5th-95th percentiles), with susceptibility to nausea, early satiety, and postprandial fullness being the major complaints. As regards EGG parameters, a significant reduction (P = 0.04; Mann-Whitney test) in the normal slow-wave percentage and significantly increased tachygastria percentage were found in dyspeptic patients compared with symptom-free patients. The tachygastria percentage was significantly associated with susceptibility to nausea score, in a non-linear fashion (R2 = 0.37). Dyspeptic patients showed lower levels of substance P and gastrin than patients who were not dyspeptic, but this difference had no clinical significance for dyspepsia.

CONCLUSIONS

Chemotherapy may induce upper gastrointestinal symptoms suggestive of motility disorders. These dyspeptic symptoms were associated with EGG alterations, but not with variations in circulating peptides. Other hormones or pathophysiological factors, not considered in the present work, could be actively involved in these dyspeptic symptoms.

Driving gastric electrical activity with electrical stimulation

Gastric electrical stimulation (GES) therapy is generating a lot of interest, but it is still investigational. Its efficacy in driving gastric electrical activity and improving motility, and the ideal frequency for bringing this about are still controversial. In this study, a rule-based computer model of tissue electrical response to stimulation was developed to examine the interaction between tissue electrical refractoriness and the onset of tissue activation. The results were compared to response to GES in 8 dogs implanted with electrodes and strain gauges and stimulated at frequencies ranging from 3 to 30 cycles/min. Simulated electrical control activity at an intrinsic frequency of 5/min was entrained from 2.0 cycles/min to 7.92 cycles/min. The regularity of the ECA elicited by stimulation depended on the number of pulses injected. Electrical stimulation in canine stomach entrained the native electrical control activity from a baseline average of 5.14 +/- 0.32 cycles/min up to 9.2 cycles/min. Contractile response to stimulation at 20-30 cycles/min were significantly higher (p < 0.05). Computer simulation of GES may be a useful tool to complement and reduce some of the costs associated with empirical studies of gastric electrical stimulation in establishing its possible use in treating drug refractory gastroparesis.

Hyperemesis gravidarum, a literature review

Hyperemesis gravidarum (HG) is a condition causing severe nausea and vomiting in early pregnancy often resulting in hospital admission. The incidence of HG is approximately 0.5% of live births, said to be higher in multiple pregnancies, hydatidiform mole and other conditions associated with increased pregnancy hormone levels. Both the aetiology and pathogenesis of HG remain unknown. We conducted a literature review (1966-now) to summarize the current evidence on the aetiology and pathogenesis of HG. The potential role of pregnancy-related hormones such as progesterone, estrogen and HCG has been widely studied; however, various other hormones such as leptin, placental growth hormone, prolactin, thyroid and adrenal cortical hormones have been implicated in the aetiology of HG. In addition to endocrinological hypotheses, the rationale and evidence considering infectious, immunological, psychological, metabolic and anatomical causes for HG have been analysed here. Many studies suffer from the low number of patients included, the variable definition used for HG and varying assay methodology used in studies of hormone measurement. This review highlights the need for more extensive studies addressing the pathogenesis and aetiology of HG.

Electrogastrography: basic knowledge, recording, processing and its clinical applications

The slow wave (SW) of the gastrointestinal (GI) tract mainly functions to trigger the onset of spike to elicit smooth muscle contraction, which provides the essential power of motility. Smooth muscle myogenic control activity or SW is believed to originate in the interstitial cells of Cajal (ICC). The electrical coupling promotes interaction between muscle cells, and ICC additionally contribute to SW rhythmicity. Stomach SW originates in the proximal body showing the continuous rhythmic change in the membrane potential and propagates normally to the distal antrum with a regular rhythm of approximately 3 c.p.m. A technique using electrodes positioned on the abdominal skin to pick up stomach rhythmic SW refers to electrogastrography (EGG). The stomach SW amplitude is very weak, while many visceral organs also produce rhythmic electricities, for example heartbeat, respiration, other organs of the GI tract and even body movements. Thus noise other than SW should be filtered out during the recording, while motion artifacts are visually examined and deleted. Finally, the best signal among all recordings is selected to compute EGG parameters based on spectral analysis. The latter is done not only to tranform frequency domain to time domain but also to provide information of time variability in frequency. Obtained EGG parameters include dominant frequency/power, % normal rhythm, % bradygastria, % tachygastria, instability coefficient and power ratio. Clinical experience in EGG has been markedly accumulated since its rapid evolution. In contrast, lack of standardized methodology in terms of electrode positions, recording periods, test meals, analytic software and normal reference values makes the significance of EGG recording controversial. Unlike imaging or manometrical studies, stomach motility disorders are not diagnosed based only on abnormal EGG parameters. Limitations of EGG recording, processing, computation, acceptable normal parameters, technique and reading should be known to conduct subjective assessments when EGG is used to resolve stomach dysfunction. Understanding basic SW physiology, recording methodology and indications may open EGG as a new domain to approach the stomach motor dysfunction.

Two-channel gastric electrical stimulation accelerates delayed gastric emptying induced by vasopressin

The aim of this study was to investigate the effects of two-channel gastric electrical stimulation (GES) on delayed gastric emptying, gastric dysrhythmias, and motion sickness-like symptoms induced by vasopressin. Seven dogs implanted with four pairs of gastric electrodes and a duodenal cannula were studied in four randomized sessions (saline, vasopressin, single-channel GES, and two-channel GES). The experiment in each session was conducted sequentially as follows: 30-min baseline, ingestion of a liquid meal, 30-min iv infusion of vasopressin or saline, and two 30-min postprandial recordings. In the GES sessions, GES was applied via the first pair of electrodes for single-channel GES or the first and third pairs of electrodes for two-channel GES. Gastric emptying was collected every 15 min via the cannula for a period of 90 min. Results were as follows. (1) Vasopressin induced gastric dysrhythmias, motion sickness-like symptoms, and delayed gastric emptying (P < 0.01, ANOVA). (2) GES normalized gastric dysrhythmias (P < 0.01) but showed no effects on vasopressin-induced emetic response. (3) Two-channel GES improved delayed gastric emptying induced by vasopressin. In comparison with the vasopressin session, two-channel GES, but not single-channel GES, significantly increased gastric emptying at 30 min (43.9+/-12.6 vs. 27.5+/-7.7%; P < 0.03), 60 min (75.3+/-15.1 vs. 54.0+/-17.8%; P < 0.05), and 90 min (91.6+/-9.8 vs. 80.3+/-9.0%; P < 0.05). GES with long pulses is able to normalize gastric dysrhythmias. Two-channel GES improves delayed gastric emptying induced by vasopressin.

Effects of vasopressin and long pulse-low frequency gastric electrical stimulation on gastric emptying, gastric and intestinal myoelectrical activity and symptoms in dogs

The aim of this study was to investigate the effect of vasopressin and long pulse-low frequency gastric electrical stimulation (GES) on gastric emptying, gastric and intestinal myoelectrical activity and symptoms in dogs. The study was performed in eight healthy female dogs implanted with four pairs of gastric serosal electrodes and two pairs of small bowel serosal electrodes, and a duodenal fistula for the assessment of gastric emptying. Each dog was studied in three sessions on three separate days in a randomized order with recordings of gastric and small bowel slow waves. Each study session consisted of 30-min baseline, 30-min stimulation and 30-min recovery period. In sessions 1 and 2, infusion of either saline or vasopressin (0.75 U kg(-1) in 30 mL saline instilled in 30 min) was given during the second 30-min period. The protocol of session 3 was the same as session 2 except long pulse-low frequency GES was performed during the second 30-min period. It was found that: (i) Vasopressin significantly delayed gastric emptying 30 and 45 min after meal and GES did not improve the vasopressin induced delayed gastric emptying; (ii) Vasopressin induced gastric dysrhythmias and GES significantly improved vasopressin induced gastric dysrhythmia; (iii) Vasopressin also induced intestinal slow wave abnormalities but GES had no effect on vasopressin induced small bowel dysrhythmia; (iv) Vasopressin induced symptoms and behaviours suggestive of nausea that were not improved by GES. We conclude that: (i) Vasopressin delays gastric emptying and induces gastric and small bowel dysrhythmias and symptoms in the fed state, and (ii) long pulse-low frequency GES normalizes vasopressin induced gastric dysrhythmia with no improvement in gastric emptying or symptoms.

Impaired gastric myoelectricity in patients with chronic pancreatitis: Role of maldigestion

AIM: To investigate whether gastric myoelectrical activity was impaired in patients with chronic pancreatitis (CP) and to explore the role of pancreatic enzyme in regulating gastric myoelectrical activity.

METHODS: Twenty CP patients and 20 controls participated in the study. Gastric myoelectrical activity was recorded by a homemade electrogastrography (EGG) device. Two experiments were carried out. In experiment one, EGG was recorded in both controls and CP patients. While in experiment two, either pancreatic enzymes or placebo was given together with test meals. Spectral analysis was used to generate various EGG parameters.

RESULTS: The control subjects, but not the CP patients, showed typically increased postprandial dominant frequency. The postprandial dominant power (DP) increment (2.24±1.13 vs 5.35±0.96 dB, P = 0.04) and the percentage of normal 2-4 cpm slow waves (63.0±3.8% vs 77.4 ±3.1%, P<0.05) were lower in CP patients when compared with the control. In the 20 CP patients, the DP increment (4.76±1.02 vs 2.53±1.20 dB, P<0.05) and the postprandial percentage of normal 2-4 cpm (74.4±2.8% vs 64.8 ±5.7%, P<0.05) were significantly higher with pancreatic enzyme replacement than the placebo.

CONCLUSION: CP patients have an abnormal postprandial stomach myoelectricity showing poor response in dominant frequency/power and regularity, whereas these abnormalities are corrected after pancreatic enzyme replacement. Maldigestion is likely to be the factor leading to abnormal postprandial gastric myoelectricity of CP patients.