The Future and Electrogastrography

2003 ◽  
Keyword(s):  
Eating Disorders ◽  
Animal Studies ◽  
Low Frequency ◽  
Neuromuscular Function ◽  
Gastric Myoelectrical Activity ◽  
Myoelectrical Activity ◽  
Sham Feeding ◽  
Egg Signal ◽  
Cells Of Cajal

The 3-cycles per minute (cpm) gastric pacesetter potential is a fundamental electrical phenomenon of the stomach. This low-frequency biorhythm is the basis for normal neuromuscular function of the stomach. In regard to the origins and the various neural and hormonal influences that affect the 3-cpm rhythm, many mysteries remain. Ongoing and future inquiries into the very nature of rhythmicity will provide deeper understanding of gastric myoelectrical activity and the electrical activity detected in the electrogastrogram (EGG). The role of knockout mice that lack interstitial cells of Cajal will be increasingly important in understanding the crucial role of rhythmic electrical events in normal and abnormal neuromuscular function of the stomach. These and other animal studies will also continue to help clinicians understand the deficits in gastric neuromuscular function caused by electrical dysrhythmias. A delicate balance maintains normal 3-cpm activity. Stomach electrical rhythmicity is rather unstable during fasting, for example, compared with the rhythmic 3-cpm electrical events and contractile events that occur in the postprandial period. What mechanisms produce these fasting and postprandial electrical changes? Are neural or hormonal circuits most critical? Are extrinsic or intrinsic nerves the most important? Studies of fasting and postprandial EGG activity may offer insights into sensations of hunger and satiety. The EGG signal is responsive to brain-gut interactions such as the cephalic-vagal reflex. Sham feeding studies with healthy subjects indicated that the sight, smell, and taste of food significantly increased 3- cpm activity. However, in subjects who indicated that the sham feeding experience was disgusting, no increase in 3-cpm activity occurred in this situation. Future studies of patients with eating disorders such as bulimia or anorexia nervosa using EGG recording methods may reveal new insights into the pathophysiology of eating disorders and be of value in monitoring the progress of treatment. Different EGG patterns induced by different meals reflect the different gastric neuromuscular work required to receive, mix, and empty the specific meal. Characteristics of the EGG signal from frequency to amplitude may also correlate with perceptions of stomach fullness, hunger, or satiety.

Atropine-Induced HRV Alteration is Not Amended by Electroacupuncture on Zusanli

2005 ◽  
Vol 33 (02) ◽  
pp. 307-314 ◽  
Author(s):  
Chi-Hsien Chang ◽  
Jin-Long Huang ◽  
Chih-Tai Ting ◽  
Chi-Sen Chang ◽  
Gran-Hum Chen
Keyword(s):  
High Frequency ◽  
Sympathetic Activity ◽  
Nervous Activity ◽  
Low Frequency ◽  
Serum Levels ◽  
Autonomic Nervous Activity ◽  
Gastric Myoelectrical Activity ◽  
Myoelectrical Activity ◽  
Autonomic Nervous ◽  
Vagal Pathway

Acupuncture is known to influence autonomic nervous activity. Acupuncture on Zusanli points has been shown to enhance the regularity of gastric myoelectrical activity and accelerate gastric emptying, partly through the vagal pathway, in dogs. The aim of this study was to evaluate whether atropine-induced autonomic nervous alteration, measured by heart rate variability (HRV), could be amended by electroacupuncture on Zusanli points. HRV measurements were recorded in 15 healthy volunteers before, during and after electroacupuncture. Each subject was studied for three sessions in a randomized sequence, which included electroacupuncture on the Zusanli (St 36) points with or without premedication of atropine and placebo stimulation on a non-acupoint. The analysis of low frequency (LF), high frequency (HF) and LF/HF ratios were compared between different sessions. Serum levels of gastrin, motilin and pancreatic polypeptide (PP) levels were also measured. There was an increase in the LF/HF ratio (indicating increased sympathetic activity) during the post-acupuncture period with 2 Hz of electrical stimulation on the Zusanli acupoints. When IV atropine was used immediately before the electroacupuncture, there was a decrease in the LF power and HF power during the acupuncture and post-acupuncture periods. In addition, there was a significant increase in the LF/HF ratio during the acupuncture and post-acupuncture periods. There was a significant decrease in serum PP in the post-acupuncture period after premedication with IV atropine. In conclusion, atropine-induced HRV change might be mediated via the vagal pathway. However, atropine-induced HRV alteration is not amended by electroacupuncture on Zusanli points.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

Serosal and cutaneous recordings of gastric myoelectrical activity in patients with gastroparesis

1994 ◽  
Vol 266 (1) ◽  
pp. G90-G98 ◽  
Author(s):  
J. D. Chen ◽  
B. D. Schirmer ◽  
R. W. McCallum
Keyword(s):  
Electrical Stimulation ◽  
Slow Wave ◽  
Test Meal ◽  
Frequency Change ◽  
Fasting State ◽  
Gastric Myoelectrical Activity ◽  
Myoelectrical Activity ◽  
Gastric Slow Wave ◽  
Student’S T ◽  
Student’S T Test

The aims of this study were to 1) investigate gastric myoelectrical activity in patients with gastroparesis, 2) validate the cutaneous electrogastrogram (EGG) in tracking the frequency change of the gastric slow wave, and 3) investigate the effect of electrical stimulation on gastric myoelectrical activity. Gastric myoelectrical activity was recorded in 12 patients with documented gastroparesis using serosal electrodes for > 200 min in each subject. All recordings were made at least 4 days after surgery. Each session consisted of a 30-min recording in the fasting state and a 30-min recording after a test meal. The test meal (liquid or mixed) was selected according to patient's tolerance. Electrical stimulation was performed in three subjects via the serosal electrodes at a frequency of 3 cycles/min. Gastric myoelectrical activity was recorded using serosal electrodes in each session. The serosal recording showed slow waves of 2.5 to 4.0 cycles/min in all 12 subjects. Absence of spikes was noted in 11 of the 12 subjects. The simultaneous serosal and cutaneous recording of gastric myoelectrical activity showed that the frequency of the EGG was exactly the same as that of the serosal recording. Liquid meals resulted in a significant decrease in slow-wave frequency (Student's t test, P = 0.006), and the EGG accurately reflected this change. Electrical stimulation had no effect on the frequency of the gastric slow wave and did not induce spikes.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Hypoxia and Mitochondrial Dysfunction in Pregnancy Complications

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 405 ◽  
Author(s):  
Xiang-Qun Hu ◽  
Lubo Zhang
Keyword(s):  
Pregnancy Complications ◽  
Intrauterine Growth Restriction ◽  
Animal Studies ◽  
Major Effect ◽  
Causative Role ◽  
Therapeutic Approaches ◽  
Maternal Complications ◽  
Mitochondrial Ros ◽  
Subsequent Risk

Hypoxia is a common and severe stress to an organism’s homeostatic mechanisms, and hypoxia during gestation is associated with significantly increased incidence of maternal complications of preeclampsia, adversely impacting on the fetal development and subsequent risk for cardiovascular and metabolic disease. Human and animal studies have revealed a causative role of increased uterine vascular resistance and placental hypoxia in preeclampsia and fetal/intrauterine growth restriction (FGR/IUGR) associated with gestational hypoxia. Gestational hypoxia has a major effect on mitochondria of uteroplacental cells to overproduce reactive oxygen species (ROS), leading to oxidative stress. Excess mitochondrial ROS in turn cause uteroplacental dysfunction by damaging cellular macromolecules, which underlies the pathogenesis of preeclampsia and FGR. In this article, we review the current understanding of hypoxia-induced mitochondrial ROS and their role in placental dysfunction and the pathogenesis of pregnancy complications. In addition, therapeutic approaches selectively targeting mitochondrial ROS in the placental cells are discussed.

Sign in / Sign up

Export Citation Format

Share Document