Diagnosis and treatment of neuromuscular disorders of the stomach

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects

Functional gastric disorders entail chronic or recurrent symptoms, high prevalence and a significant financial burden. These disorders do not always involve structural abnormalities and since they cannot be diagnosed by routine procedures, electrogastrography (EGG) has been proposed as a diagnostic alternative. However, the method still has not been transferred to clinical practice due to the difficulty of identifying gastric activity because of the low-frequency interference caused by skin-electrode contact potential in obtaining spatiotemporal information by simple procedures. This work attempted to robustly identify the gastric slow wave (SW) main components by applying multivariate variational mode decomposition (MVMD) to the multichannel EGG. Another aim was to obtain the 2D SW vectorgastrogram VGGSW from 4 electrodes perpendicularly arranged in a T-shape and analyse its dynamic trajectory and recurrence quantification (RQA) to assess slow wave vector movement in healthy subjects. The results revealed that MVMD can reliably identify the gastric SW, with detection rates over 91% in fasting postprandial subjects and a frequency instability of less than 5.3%, statistically increasing its amplitude and frequency after ingestion. The VGGSW dynamic trajectory showed a statistically higher predominance of vertical displacement after ingestion. RQA metrics (recurrence ratio, average length, entropy, and trapping time) showed a postprandial statistical increase, suggesting that gastric SW became more intense and coordinated with a less complex VGGSW and higher periodicity. The results support the VGGSW as a simple technique that can provide relevant information on the "global" spatial pattern of gastric slow wave propagation that could help diagnose gastric pathologies.

Endoscopic mucosal electrodes: New directions for recording and regulating gastric myoelectric activity

With the gradual deepening of the study of gastric motility disorders, people increasingly realize that gastric myoelectric activity plays an important role in coordinating gastric function. This article introduces the advantages of endoscopic mucosal electrodes compared with traditional electrodes. Several different types of mucosal electrodes and how to fix the electrodes by endoscope are introduced. Endoscopic mucosal electrodes can record and regulate gastric myoelectric activity, which has great value in the study of gastric motility. Endoscopic mucosal electrode technique refers to the fixation of the electrode in the designated part of the gastric mucosa by endoscope. Through endoscopic mucosal electrodes, on the one hand, we can record gastric myoelectric activity, on the other hand, we can carry out gastric electrical stimulation to interfere with gastric rhythm. Endoscopic mucosal electrodes have higher accuracy than traditional cutaneous electrodes, less trauma and lower cost than serosal electrodes. Endoscopic mucosal electrodes have a good application prospect for diseases such as gastroparesis and obesity.

J-pouch versus Roux-en-Y reconstruction after gastrectomy: functional assessment and quality of life (randomized trial)

Purpose

The aim of this study was to evaluate the quality of life and functional emptying of J-pouch versus Roux-en-Y reconstruction after total gastrectomy for malignancy.

Methods

This study was designed as a prospective, nonblinded, randomized, parallel clinical trial (Trial Number: MN Ostrava, 200604). With informed consent, patients undergoing gastrectomy for malignancy were randomized to J-pouch or Roux-en-Y reconstruction. The time taken for a test semisolid meal labeled with ^99mTc-sulfur colloid to exit the reconstructed parts was measured by dynamic scintigraphy 1 year after resection. Quality of life was measured using the Eypasch questionnaire at the same time as functional emptying assessment. This trial was investigator-initiated.

Results

In all, 72 patients were included into the study. The time taken for the test meal to exit the postgastrectomy reconstruction was 16.5±10.0 minutes (mean ± standard deviation) in the Roux-en-Y group and 89.4±37.8 minutes in the “J-pouch” group; the difference was statistically significant (P<0.001). Emptying of the J-pouch appeared to be a linear decreasing function compared to the exponential pattern seen in the Roux-en-Y group. The quality of life measurement showed scores of 106±18.8 points (mean ± standard deviation) in the Roux-en-Y group compared to 122±22.5 points in the J-pouch group; the difference was statistically significant (P=0.0016). There were no important adverse events.

Conclusion

After total gastrectomy, a J-pouch reconstruction empties more slowly and is associated with higher quality of life compared to Roux-en-Y reconstruction. Whether these two observations have a direct causative link remains unanswered.

Enhanced perceptions of control and predictability reduce motion-induced nausea and gastric dysrhythmia

Nausea is a debilitating condition that is typically accompanied by gastric dysrhythmia. The enhancement of perceived control and predictability has generally been found to attenuate the physiological stress response. The aim of the present study was to test the effect of these psychosocial variables in the context of nausea, motion sickness, and gastric dysrhythmia. A 2x2, independent-groups, factorial design was employed in which perceived control and predictability were each provided at high or low levels to 80 participants before exposure to a rotating optokinetic drum. Ratings of nausea were obtained throughout a 6-min baseline period and a 16-min drum rotation period. Noninvasive recordings of the electrical activity of the stomach called electrogastrograms were also obtained throughout the study. Nausea scores were significantly lower among participants with high control than among those with low control, and were significantly lower among participants with high predictability than among those with low predictability. Estimates of gastric dysrhythmia obtained from the EGG during drum rotation were significantly lower among participants with high predictability than among those with low predictability. A significant interaction effect of control and predictability on gastric dysrhythmia was also observed, such that high control was only effective for arresting the development of gastric dysrhythmia when high predictability was also available. Stronger perceptions of control and predictability may temper the development of nausea and gastric dysrhythmia during exposure to provocative motion. Psychosocial interventions in a variety of nausea contexts may represent an alternative means of symptom control.

Regulation of smooth muscle contraction by the epithelium: role of prostaglandins

As an analog to the endothelium situated next to the vascular smooth muscle, the epithelium is emerging as an important regulator of smooth muscle contraction in many vital organs/tissues by interacting with other cell types and releasing epithelium-derived factors, among which prostaglandins have been demonstrated to play a versatile role in governing smooth muscle contraction essential to the physiological and pathophysiological processes in a wide range of organ systems.

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.