scholarly journals A Flexible Multiring Concentric Electrode for Non-Invasive Identification of Intestinal Slow Waves

Sensors ◽  
2018 ◽  
Vol 18 (2) ◽  
pp. 396 ◽  
Author(s):  
Victor Zena-Giménez ◽  
Javier Garcia-Casado ◽  
Yiyao Ye-Lin ◽  
Eduardo Garcia-Breijo ◽  
Gema Prats-Boluda
Keyword(s):  
Slow Waves ◽  
Non Invasive ◽  
Intestinal Slow Waves ◽  
Concentric Electrode

Gastrointestinal myoelectric activity in conscious guinea pigs

1985 ◽  
Vol 249 (1) ◽  
pp. G92-G99 ◽  
Author(s):  
J. J. Galligan ◽  
M. Costa ◽  
J. B. Furness
Keyword(s):  
Small Intestine ◽  
Guinea Pigs ◽  
Mammalian Species ◽  
Gastric Antrum ◽  
Slow Waves ◽  
Cycle Period ◽  
Myoelectric Activity ◽  
Phase 3 ◽  
Fed State ◽  
Intestinal Slow Waves

Myoelectric activity was recorded from the gastric antrum and small intestine of conscious, unrestrained guinea pigs using bipolar Ag-Ag chloride electrodes that had been previously implanted under pentobarbital sodium/Innovar anesthesia. In fasted guinea pigs, the migrating myoelectric complex (MMC) was recorded from the small intestine and was observed to propagate aborally at a speed that declined with distance from the pylorus (range of speeds of the front of phase 3: 17.5 cm/min in the duodenum to 4.1 cm/min in the ileum). The complex was not disrupted by feeding but occurred less frequently in the freely fed state (82-min cycle period in the fasted state versus 139 min in the fed state). The complex started in the duodenum and was accompanied by a brief (6.3 +/- 0.9 min) period of inhibition of antral myoelectric activity. Slow waves were also recorded from the gastric antrum (10.3 +/- 1.3/min) and the small intestine. The frequency of intestinal slow waves was uniform along the length of the bowel (26.2 +/- 1.3/min in the duodenum to 24.7 +/- 1.3/min in the ileum). It is concluded that the guinea pig is similar to other mammalian species, so far examined, in its pattern of gastrointestinal myoelectric activity.

scholarly journals Validation of non-invasive cerebrovascular pressure reactivity and pulse amplitude reactivity indices in traumatic brain injury

2019 ◽  
Vol 162 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Leanne A. Calviello ◽  
András Czigler ◽  
Frederick A. Zeiler ◽  
Peter Smielewski ◽  
Marek Czosnyka
Keyword(s):  
Correlation Coefficient ◽  
Pulse Amplitude ◽  
Slow Waves ◽  
Reactivity Index ◽  
Non Invasive ◽  
Reactivity Indices ◽  
Full Waveform ◽  
Arterial Blood ◽  
Pressure Reactivity ◽  
Predictive Strength

Abstract Background Two transcranial Doppler (TCD) estimators of cerebral arterial blood volume (CaBV) coexist: continuous outflow of arterial blood outside the cranium through a low-pulsatile venous system (continuous flow forward, CFF) and pulsatile outflow through regulating arterioles (pulsatile flow forward, PFF). We calculated non-invasive equivalents of the pressure reactivity index (PRx) and the pulse amplitude index PAx with slow waves of mean CaBV and its pulse amplitude. Methods About 273 individual TBI patients were retrospectively reviewed. PRx is the correlation coefficient between 30 samples of 10-second averages of ICP and mean ABP. PAx is the correlation coefficient between 30 samples of 10-second averages of the amplitude of ICP (AMP, derived from Fourier analysis of the raw full waveform ICP tracing) and mean ABP. nPRx is calculated with CaBV instead of ICP and nPAx with the pulse amplitude of CaBV instead of AMP (calculated using both the CFF and PFF models). All reactivity indices were additionally compared with Glasgow Outcome Score (GOS) to verify potential outcome-predictive strength. Results When correlated, slow waves of ICP demonstrated good coherence between slow waves in CaBV (>0.75); slow waves of AMP showed good coherence with slow waves of the pulse amplitude of CaBV (>0.67) in both the CFF and PFF models. nPRx was moderately correlated with PRx (R = 0.42 for CFF and R = 0.38 for PFF; p < 0.0001). nPAx correlated with PAx with slightly better strength (R = 0.56 for CFF and R = 0.41 for PFF; p < 0.0001). nPAx_CFF showed the strongest association with outcomes. Conclusions Non-invasive estimators (nPRx and nPAx) are associated with their invasive counterparts and can provide meaningful associations with outcome after TBI. The CFF model is slightly superior to the PFF model.

Effects of alterations in calcium levels on cat small intestinal slow waves

1982 ◽  
Vol 243 (1) ◽  
pp. C7-C13 ◽  
Author(s):  
A. W. Mangel ◽  
J. A. Connor ◽  
C. L. Prosser
Keyword(s):  
Intracellular Calcium ◽  
Slow Wave ◽  
Calcium Concentration ◽  
Longitudinal Muscle ◽  
Slow Waves ◽  
Wave Frequency ◽  
Intracellular Calcium Concentration ◽  
Magnesium Concentration ◽  
Reduced Frequency ◽  
Intestinal Slow Waves

Intact segments of cat intestinal muscle and strips of isolated longitudinal muscle were treated with agents that reduce intracellular calcium concentration: incubation in 0-calcium saline, treatment with calcium conductance blockers, elevated extracellular magnesium concentration, or alkalinization with NH4Cl. These treatments reduced amplitude and frequency of slow waves in intact segments but only reduced frequency in isolated longitudinal muscle. The reduction in frequency was characterized by prolongation of the hyperpolarized phase of the slow waves. Treatments that would moderately increase intracellular calcium concentration, i.e., increasing external calcium to four times normal levels or lowering pH by CO2, increased slow-wave frequency. Increased frequency was associated with reduced amplitude and shortening of the hyperpolarized phase of the slow waves. Greater than four times normal calcium levels and intense spiking reduced slow-wave frequency. Chlorotetracycline fluorescence, an indicator of intracellular calcium concentration, showed fluctuations synchronous with slow waves. It is concluded that the reactions that pace the generation of slow waves are dependent on the level of intracellular calcium.

Propagation and electrical entrainment of intestinal slow waves

1972 ◽  
Vol 17 (4) ◽  
pp. 311-316 ◽  
Author(s):  
Philip C. Specht ◽  
Alex Bortoff
Keyword(s):  
Slow Waves ◽  
Intestinal Slow Waves

scholarly journals Effects and mechanisms of gastrointestinal electrical stimulation on slow waves: a systematic canine study

2009 ◽  
Vol 297 (5) ◽  
pp. R1392-R1399 ◽  
Author(s):  
Yan Sun ◽  
Geng-Qing Song ◽  
Jieyun Yin ◽  
Yong Lei ◽  
Jiande D. Z. Chen
Keyword(s):  
Small Intestine ◽  
Electrical Stimulation ◽  
Receptor Antagonist ◽  
Adrenergic Receptor ◽  
Slow Waves ◽  
Optimal Parameters ◽  
Small Intestinal ◽  
Intestinal Slow Waves ◽  
Canine Study ◽  
Dominant Frequencies

The aims of this study were to determine optimal pacing parameters of electrical stimulation on different gut segments and to investigate effects and possible mechanisms of gastrointestinal electrical stimulation on gut slow waves. Twelve female hound-mix dogs were used in this study. A total of six pairs of electrodes were implanted on the stomach, duodenum, and ascending colon. Bilateral truncal vagotomy was performed in six of the dogs. One experiment was designed to study the effects of the pacing frequency on the entrainment of gut slow waves. Another experiment was designed to study the modulatory effects of the vagal and sympathetic pathways on gastrointestinal pacing. The frequency of slow waves was 4.88 ± 0.23 cpm (range, 4–6 cpm) in the stomach and 19.68 ± 0.31 cpm (range, 18–22 cpm) in the duodenum. There were no consistent or dominant frequencies of the slow waves in the colon. The optimal parameters to entrain slow waves were: frequency of 1.1 intrinsic frequency (IF; 10% higher than IF) and pulse width of 150–450 ms (mean, 320.0 ± 85.4 ms) for the stomach, and 1.1 IF and 10–20 ms for the small intestine. Electrical stimulation was not able to alter colon slow waves. The maximum entrainable frequency was 1.27 IF in the stomach and 1.21 IF in the duodenum. Gastrointestinal pacing was not blocked by vagotomy nor the application of an α- or β-adrenergic receptor antagonist; whereas the induction of gastric dysrhythmia with electrical stimulation was completely blocked by the application of the α- or β-adrenergic receptor antagonist. Gastrointestinal pacing is achievable in the stomach and small intestine but not the colon, and the maximal entrainable frequency of the gastric and small intestinal slow waves is about 20% higher than the IF. The entrainment of slow waves with gastrointestinal pacing is not modulated by the vagal or sympathetic pathways, suggesting a purely peripheral or muscle effect.

scholarly journals Shaping the slow waves of sleep: A systematic and integrative review of sleep slow wave modulation in humans using non-invasive brain stimulation

2021 ◽  
Vol 58 ◽  
pp. 101438
Author(s):  
Kristoffer D. Fehér ◽  
Marina Wunderlin ◽  
Jonathan G. Maier ◽  
Elisabeth Hertenstein ◽  
Carlotta L. Schneider ◽  
...  
Keyword(s):  
Slow Wave ◽  
Brain Stimulation ◽  
Slow Waves ◽  
Integrative Review ◽  
Wave Modulation ◽  
Non Invasive
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