Dominant Frequency Peak Research Articles

Characterizing the persistent CA3 interneuronal spiking activity in elevated extracellular potassium in the young rat hippocampus

Seizures coincide with an increase in extracellular potassium concentrations [K +] e yet little information is available regarding this phenomenon on the firing pattern, frequency and neuronal properties of inhibitory neurons responsible for modulating network excitability. Therefore, we investigated the effects of elevating [K +] e from 2.5 to 12.5 mM on CA3 rat hippocampal interneurons in vitro using whole-cell patch-clamp recordings. We found that the majority of interneurons (21/25) in artificial cerebral spinal fluid (aCSF) exhibited spontaneous tonic spiking activity. As the [K +] e increased to 12.5 mM, interneurons exhibited a tonic, irregular, burst firing activity, or a combination of these. The input resistance decreased significantly to 59 ± 18% at 7.5 mM K + and did not further change at higher [K +] e while the amount of K +-induced depolarization significantly increased from 5 to 12.5 mM K + perfusion; a depolarization block occurred in 4 of the 12 interneurons at 12.5 mM. Also, as [K +] e increased, a transition from lower (1.3 ± 0.6 Hz) to higher dominant peak frequency (15.0 ± 5.0 Hz) was observed. We found that non-fast spiking (NFS) interneurons represented the majority of cells recorded and exhibited mostly tonic firing activity in raised K +. Fast spiking (FS) interneurons predominately had a tonic firing pattern with very few exhibiting bursting activity in elevated K +. In conclusion, we report that raised [K +] e in amounts observed during seizures increases hippocampal CA3 interneuronal activity and suggests that a loss or impairment of inhibitory function may be present during these events.

풍력터빈 블레이드 주위 흐름의 유동특성에 대한 실험적 분석

The flow and noise characteristics of wake behind wind-turbine blades have been investigated experimentally using a two-frame particle image velocimetry (PIV) technique. Experiments were carried out in a POSTECH subsonic large wind-tunnel (<TEX>$1.8^W{\times}1.5^H{\times}4.3^L\;m^3$</TEX>) with KBP-750D (3-blade type) wind-turbine model at a freestream velocity of <TEX>$U_o\;=\;15\;m/s$</TEX> and a tip speed ratio <TEX>$\lambda\;=\;6.14$</TEX> (2933 rpm). The wind-turbine blades are connected to an AC servo motor, brake, encoder and torque meter to control the rotational speed and to extract a synchronization signal for PIV measurements. The wake flow was measured at four azimuth angles (<TEX>$\phi\;=\;0^{\circ}$</TEX>, <TEX>$30^{\circ}$</TEX>, <TEX>$60^{\circ}$</TEX> and <TEX>$90^{\circ}$</TEX>) of the wind-turbine blade. The dominant flow structure of the wake is large-scale tip vortices. The turbulent statistics such as turbulent intensity are weakened as the flow goes downstream due to turbulent dissipation. The dominant peak frequency of the noise signal is identical to the rotation frequency of blades. The noise seems to be mainly induced by the tip vortices.

Frequency Analysis of Atrial Electrograms Identifies Conduction Pathways from the Left to the Right Atrium During Atrial Fibrillation—Studies in Two Canine Models

Studies of atrial fibrillation (AF) have demonstrated that a stable rhythm of very short cycle length in the left atrium (LA) can cause fibrillatory conduction in the rest of the atria. We tested the hypothesis that fast Fourier transform (FFT) analysis of atrial electrograms (AEGs) during this AF will rapidly and reliably identify LA-to-right atrium (RA) conduction pathway(s) generated by the driver. During induced atrial tachyarrhythmias in the canine sterile pericarditis and rapid ventricular pacing-induced congestive heart failure models, 380-404 AEGs were recorded simultaneously from epicardial electrodes on both atria. FFT analysis of AEGs during AF demonstrated a dominant frequency peak in the LA (driver), and multiple frequency peaks in parts of the LA and the most of the RA. Conduction pathways from the LA driver to the RA varied from study-to-study. They were identified by the presence of multiple frequency peaks with one of the frequency peaks at the same frequency as the driver, and traveled (1) inferior to the inferior vena cava (IVC); (2) between the superior vena cava and the right superior pulmonary vein (RSPV); (3) between the RSPV and the right inferior pulmonary vein (RIPV); (4) between the RIPV and the IVC; and (5) via Bachmann's bundle. Conduction pathways identified by FFT analysis corresponded to the conduction pathways found in classical sequence of activation mapping. Computation time for FFT analysis for each AF episode took less than 5 minutes. FFT analysis allowed rapid and reliable detection of the LA-to-RA conduction pathways in AF generated by a stable and rapid LA driver.

Coupling of Pi2 wave energy in the inner magnetosphere as inferred from low-latitude ground observations

Taking advantage of high time-resolution (1 s) geomagnetic field measurements obtained at low-latitude stations, we investigated frequency differences of Pi2 pulsations between the dayside and the nightside. Firstly, we examined two Pi2 cases globally observed by multiple ground stations and found that the dominant frequency peaks at the dayside showed latitudinal dependence, i.e., the higher (lower) frequency peak was predominant at lower (higher) latitude. We also noticed that the dominant Pi2 frequency on the nightside was apparently higher than that on the dayside. We argue that the multiple frequency peaks observed on the ground are harmonics of a plasmaspheric cavity resonance mode (CRM) and that the latitudinal dependence of the dominant frequency peaks may result from the energy coupling between the CRM and field line resonance (FLR) occurred in the near Earth space. We also argue that the frequency difference between the dayside and the nightside could be caused by the reason that a higher harmonic was observed in the nightside plasmasphere but was not effectively observed in the dayside. In addition, we statistically examined 829 Pi2 events that were simultaneously recorded at Kakioka (KAK, Maglat=27.2°) and Jicamarca (JIC, Maglat=0.0°), the two stations separated by ∼10 h in local time (LT) and one of them (JIC) is located at the dip equator. We found that the Pi2 frequency observed at KAK on the nightside was higher than that observed at JIC on the dayside on average. After investigating the occurrence histogram of the frequency difference (Δf=fJIC?fKAK) for the events simultaneously observed at KAK and JIC, we found that close to half of the events had the identical frequency (|Δf|<1.0 mHz). The statistical results are consistent with the facts reflected by case studies.

Application of the L-M optimized algorithm to predicting blast vibration parameters

Currently, the regression empirical formula with vibration peak as the safety index of single blasting vibration is widely applied in blasting engineering circles throughout the world. Due to complex blasting mechanism and blasting medium environment as well as plural influencing factors, it is difficult that all these factors can be taken into consideration by using one regression empirical formula. In addition, due to the inherent limitations of regression analysis (e.g., requiring good data distribution and large amount of samples), the vibration prediction by empirical formula is not ideal (LI, 1997; CHEN, 2001; ZHANG, 2001). It is developing rapidly that multilayer feedforward network is used to solve the nonlinear separable problem due to the appearance of back-propagation algorithm (YAN and ZHANG, 2000), the multilayer feedforward network was also used for the prediction field of the blast seismic hazard in recent years, and good prediction results have been obtained ( YE et al, 2003; XIA et al, 2004; Singh and Singh, 2005; TANG et al, 2007). However, in all these studies, the peak of particle vibration was used as the unique output parameter of the network model, but the important role of blasting vibration frequency in the blast seismic hazard was neglected. Recent research by many scholars shows that the destruction of buildings not only depends on particle vibration intensity, but also is closely related to the vibration frequency (HU, 1999; TANG et al, 2001 ). The neural network with improved BP algorithm (L-M algorithm) is used to establish the blasting vibration peak-dominant frequency prediction model. This method, which accords with the requirements of evaluation standard specified in “Rules of Explosion Safety” (Ministry of Labor and Ministry of Personnel of People’s Republic of China, 2003) in which the peak is combined with dominant frequency, provides a feasible predicting idea for the implementation of safety criteria for blasting vibration in which the peak is combined with dominant frequency.

Studies on the influence of grinding wheel bond material on the grindability of metal matrix composites

A study on grinding with resin bonded and plated diamond abrasive wheels have been carried out to evaluate the significance of bond on wheel performance. The performance indicators namely grinding force, acoustic emission signals emanating from the workpiece and temperature were monitored. Surface finish of the machined surface was measured using a perthometer. The electroplated wheel experiences higher order grinding force components compared to resin bonded wheel, since resin bonded diamond wheel presents sharper/keen edged abrasives, unlike the presence of smeared abrasive in case of plated wheel. The acoustic emission (AE) power spectra for the electroplated wheel shows dominant low frequency peaks of relatively higher order compared to resin bonded wheel. This can be attributed to sliding dominated grinding associated with higher order grinding force components. The electroplated wheel experiences higher temperature with low depth of grinding, while a visible reduction in temperature can be seen with higher depth of grinding. Resin bonded wheel gave better surface finish compared to the electroplated wheel. As a whole, resin bonded wheel performed better than electroplated wheel.

Shifting Breast Cancer Trends in the United States

United States breast cancer incidence rates declined during the years 1999 to 2003, and then reached a plateau. These recent trends are impressive and may indicate an end to decades of increasing incidence. To put emerging incidence trends into a broader context, we examined age incidence patterns (frequency and rates) during five decades. We used age density plots, two-component mixture models, and age-period-cohort (APC) models to analyze changes in the United States breast cancer population over time. The National Cancer Institute's Connecticut Historical Database and Surveillance, Epidemiology, and End Results program collected 600,000+ in situ and invasive female breast cancers during the years 1950 to 2003. Before widespread screening mammography in the early 1980s, breast cancer age-at-onset distributions were bimodal, with dominant peak frequency (or mode) near age 50 years and smaller mode near age 70 years. With widespread screening mammography, bimodal age distributions shifted to predominant older ages at diagnosis. From 2000 to 2003, the bimodal age distribution returned to dominant younger ages at onset, similar to patterns before mammography screening. APC models confirmed statistically significant calendar-period (screening) effects before and after 1983 to 1987. Breast cancer in the general United States population has a bimodal age at onset distribution, with modal ages near 50 and 70 years. Amid a background of previously increasing and recently decreasing incidence rates, breast cancer populations shifted from younger to older ages at diagnosis, and then back again. These dynamic fluctuations between early-onset and late-onset breast cancer types probably reflect a complex interaction between age-related biologic, risk factor, and screening phenomena.

Assessment of gastric retention time through a magnetic indigestible particle: Preliminary results

Abstract In this work the gastrointestinal activity in 7 healthy subjects was measured with a set of three fluxgate magnetometers. The activity was detected by the ingestion of a magnetic marker, which was ingested with different gastric lumen contents (in basal condition and postprandial state with 80 g and 160 g). A descriptive statistical analysis of the gastric emptying measured performed in the Fourier space shows significant variations of the mechanical activity: 100 ± 34%, 171 ± 86%, and 237 ± 71% for each condition, respectively. This information suggests the different regions where the marker was monitored. With the information of the dominant frequency peaks and an exponential fit, the gastric half-time could be estimated.

Developmental effects of ketamine on inspiratory hypoglossal nerve activity studied in vivo and in vitro

The effects of the anesthetic ketamine on properties of inspiratory bursts (I-bursts) in mouse hypoglossal nerve activity were studied in vivo and in vitro. In urethane anesthetized mice we observed rhythmic I-phase activity in only one of eight pups at P9 days. In contrast in older mice rhythmic I-phase hypoglossal activity was almost always observed. Ketamine caused a reduction in I-burst frequency and an increase in peak integrated hypoglossal nerve activity in all three age groups studied (P10-P13, P15-P20 and adult mice). In these mice I-phase oscillations, due to hypoglossal motoneurons firing clusters of action potentials at a particular frequency, were observed in control and after ketamine. Ketamine did not change the frequency of the dominant spectral peak determined from power spectra examined from 0 to 200 Hz. The effects of ketamine were also studied in vitro in the mouse rhythmic medullary slice preparation. Ketamine reduced hypoglossal I-burst frequency and I-burst peak integrated amplitude. Oscillations were observed in I-phase activity, and as in the in vivo studies ketamine did not shift the dominant spectral peak frequency. These results demonstrate that in vivo and in vitro ketamine results in significant changes in I-burst frequency and peak integrated hypoglossal nerve activity, but changes in the oscillation frequency are minimal.

Environmental Impact of Detonation of Explosives in Seismic Survey Operations

Seismic survey operations are short-term, although, they can cause annoyance to the surrounding inhabitants. These annoyances may be due to generation of ground vibrations and noise and their possible impact on the surrounding houses and other structures. The paper discusses a case study of experimental trials conducted at three different exploration sites of Oil India Limited in Assam, India. The impact of ground vibrations and noise generated due to detonation of explosives were investigated on the surrounding environment and structures in various working conditions. The maximum magnitude of vibration recorded near a residential house was 53.01 mm/s at a distance of 20 m from the blast site with the dominant peak frequency of 56.8 Hz. No adverse impact on the structure was observed. The analyses of data revealed that the ground vibrations generated due to the detonation of explosives were having their most of the energy in higher dominant frequency bands i.e. more than 30 Hz. The analyses of data clearly indicated that the magnitude of ground vibration enhances when the shot holes are stemmed. In general, the enhancement in vibration was 9–29 % but in some cases, it was observed up to 31.7 %. The level of vibration also increases as the depth of burial of explosives is increased. It was observed that whenever the confinement of explosives will be more, higher magnitude of vibrations would be generated. The magnitude of noise generated during seismic survey operations were well within the safe limits.

Developmental effects of ketamine on inspiratory hypoglossal nerve activity studied in vivo and in vitro

The effects of the anesthetic ketamine on properties of inspiratory bursts (I-bursts) in mouse hypoglossal nerve activity were studied in vivo and in vitro. In urethane anesthetized mice we observed rhythmic I-phase activity in only one of eight pups at P9 days. In contrast in older mice rhythmic I-phase hypoglossal activity was almost always observed. Ketamine caused a reduction in I-burst frequency and an increase in peak integrated hypoglossal nerve activity in all three age groups studied (P10-P13, P15-P20 and adult mice). In these mice I-phase oscillations, due to hypoglossal motoneurons firing clusters of action potentials at a particular frequency, were observed in control and after ketamine. Ketamine did not change the frequency of the dominant spectral peak determined from power spectra examined from 0 to 200 Hz. The effects of ketamine were also studied in vitro in the mouse rhythmic medullary slice preparation. Ketamine reduced hypoglossal I-burst frequency and I-burst peak integrated amplitude. Oscillations were observed in I-phase activity, and as in the in vivo studies ketamine did not shift the dominant spectral peak frequency. These results demonstrate that in vivo and in vitro ketamine results in significant changes in I-burst frequency and peak integrated hypoglossal nerve activity, but changes in the oscillation frequency are minimal.

On Computing Dominant Frequency From Bipolar Intracardiac Electrograms

Dominant frequency (DF) computed from action potentials is a key parameter for investigating atrial fibrillation in animal studies and computer models. A recent clinical trial reported consistent results computing DF from 30 Hz to 400 Hz bandpass filtered bipolar electrograms in humans. The DF (< 15 Hz and, thus, filtered out) was recovered by rectifying the signal, while the theoretical background of this approach was left uncommented. It is the focus of this paper to provide this background by a Fourier analysis. We demonstrate that it is mainly the timing of the narrow deflections (local activation at the catheter tip) which contribute to the DF peak in the frequency spectrum. Due to the typical signal morphology pronounced harmonic peaks occur in the spectrum. This is a disadvantage when computing the regularity index (RI) as a parameter for local organization and signal quality. It is demonstrated for synthetical and patient data that at low DF the RI is far below the optimal value one even for high underlying organization and good signal quality. The insight obtained promotes the development of better measures for organization. The finding that mainly timing of activation contributes to DF might promote the development of powerful realtime signal processing tools for computing DF.

Abstract 191: Analysis Of Conduction Block During Ventricular Fibrillation In Langendorff Perfused Explanted Human Hearts.

Purpose Rotors in Ventricular Fibrillation (VF) are known to occur in distinct domains identified by dominant frequency (DF). It has been postulated that VF is driven by these domains of excitation with fibrillatory propagation to adjacent domains with conduction blocks. If the dominant domain hypothesis is applicable to human VF, we postulated that minimally during VF, areas blocks in a DF map should localize at boundaries of DF domains. Methods Explanted hearts from 4 patients undergoing cardiac transplant were perfused with Krebs-Henseilet solution. The epicardial and endocardial mapping was constructed with 112 electrodes disposed on an extensible sock and balloon array. The electrodes were organized in 14 rows of 8 electrodes disposed radially around the apex. 12 episodes of VF from the 4 hearts were analyzed. Fast Fourier Transformation (FFT) analysis was performed with a resolution of 0.25 Hz. DF domain was defined as a region on the DF map with uniform DF. Double peak (DP) an estimate of conduction block, was identified at a time point if a secondary peak was present in the power spectrum of an FFT that was within a maximum separation of 80% of the dominant (highest) peak frequency and that had an amplitude of at least 20% of the amplitude of the dominant peak. Results The average DF was 4.64±1.20 Hz. The mean percentage of blocks was 26.13±12.19 %. The average number of domains per DF map were 9.25±3.77. The mean percent block per domain was 2.95±1.27.The number of domains per map correlated significantly to areas with blocks. (r = 0.49, p=0.014). When the hearts were individually analyzed, the correlation was greater than when analyzed together. Higher occurrence of block is seen with increasing number of DF domains. Conclusions During human VF, areas of blocks in a DF map localize at boundaries of DF domains.

Mapping of Atrial Activation During Sustained Atrial Fibrillation in Dogs with Rapid Ventricular Pacing Induced Heart Failure: Evidence for a Role of Driver Regions

Dogs with rapid ventricular pacing (RVP)-induced congestive heart failure (CHF) have inducible atrial tachycardia, flutter, and fibrillation (AF). We tested the hypothesis that rapid atrial activation in multiple regions and at different rates is responsible for sustained AF in this CHF model. We studied 12 episodes of sustained (>10 minutes) AF induced in 12 dogs with CHF produced by 3-6 weeks of RVP at 230 beats/minute. High-density mapping of AF was performed using 382 unipolar atrial electrograms recorded simultaneously from epicardial electrodes on the right (RA) and left atria (LA) and Bachmann's bundle. AF mechanisms were based on Fast Fourier Transform (FFT) analysis and activation sequence mapping. A driver was defined as a rapid stable activation region with a single dominant frequency peak in FFT analysis. During AF, three FFT and activation patterns were seen: (1) a single LA driver (7.8 +/- 1.1 Hz) near the pulmonary veins (PVs) with irregular activation in the rest of the atria (n = 4); (2) simultaneous, multisite, biatrial drivers at differing frequencies (LA vs RA dominant frequency gradient: 1.3 +/- 0.8 Hz) near the PVs (8.4 +/- 0.3 Hz) and high RA (8.5 +/- 1.5 Hz) (n = 7); and (3) biatrial irregular activation with multiple and/or broadband frequency peaks without a dominant frequency. (LA: 7.1-11.4 Hz; RA: 5.9-7.7 Hz) (n = 1). Atrial drivers had either a focal activation pattern or were due to a macroreentrant circuit around the PVs. In this CHF model, FFT analysis and activation sequence mapping demonstrate that sustained AF is characterized by single and multiple, stable LA and RA drivers with predominant sources in the PVs and high RA causing fibrillatory conduction.

Use of Fast Fourier Transform Analysis of Atrial Electrograms for Rapid Characterization of Atrial Activation—Implications for Delineating Possible Mechanisms of Atrial Tachyarrhythmias

Different analysis techniques have been developed to help understand and characterize the mechanisms responsible for atrial arrhythmias. We tested the hypothesis that Fast Fourier Transform (FFT) analysis of recorded atrial electrograms (AEGs) will rapidly and accurately identify regular and irregular patterns of atrial activation, and, thereby, may provide evidence suggestive of underlying mechanisms of atrial tachyarrhythmias. During induced atrial tachyarrhythmias in both the canine sterile pericarditis model and canine rapid ventricular pacing-induced congestive heart failure model; 380-404 AEGs were recorded simultaneously from epicardial electrodes on both atria. From AEGs, atrial activation sequences were determined during atrial flutter (AFL), focal atrial tachycardia (AT), and atrial fibrillation (AF). Four-second recording segments of each AEG were subjected to FFT analysis. Frequencies found during FFT analyses in all studies precisely corresponded to the cycle lengths of the AEGs. In AFL and AT, one dominant frequency peak was found throughout both atria. In AF due to multiple unstable reentry circuits, multiple and broad frequency peaks were found in both atria. In AF due to a stable rapid rhythm (driver) in the left atrium with fibrillatory conduction to the rest of the atria, one dominant frequency peak in areas with 1:1 conduction from the driver, and multiple and/or broad frequency peaks in areas with fibrillatory conduction produced by the driver were found. Computation time for all FFT analyses took <5 minutes. FFT analysis accurately and rapidly identifies global atrial activation patterns during AFL, AT, and AF, thereby assisting in determining arrhythmia mechanisms.

Influence of floor motions in wind tunnels on the aerodynamics of road vehicles

The effect of a moving floor on the flow around a simplified car with a typical fastback geometry is investigated. Two large-eddy simulations of the flows with stationary and moving floors are made and both instantaneous and time-averaged results are compared. It is found that the floor motion reduces drag by 8 % and lift by 16 % . Changes in the flow are found to be global but are largest close to the floor and on the rear slanted surface of the vehicle. The wake flow is found to be relatively insensitive to the floor movement, in agreement with previous experimental observations. The periodicity of the flow events is found to be dependent on whether the floor is moving. Power spectral density of both the lift and the drag contain only one dominant frequency peak when the moving floor is adopted as compared to scattered spectra in the stationary floor case. Changes in the qualitative picture of the flow are limited to the flow near the floor and on the slanted surface of the body. However, changes in the surface pressure on the body and the history of the flow show the need of a moving floor in experimental and numerical simulations.

Routine Neurophysiologic Tremor Analysis as a Diagnostic Tool for Essential Tremor: A Prospective Study

The objective of the current study was to investigate the diagnostic potential of the routine tremor neurophysiologic analysis for the diagnosis of essential tremor (ET) in patients with postural tremor syndrome. Three hundred consecutive outpatients attending for postural tremor were included. Accelerometry and surface electromyography was performed between 1 and 4 weeks after the first clinical visit. A final clinical diagnosis (mean follow-up period, 53 months) of the postural tremor syndrome was made by two neurologists blind to the neurophysiologic results. Six neurophysiologic criteria for the diagnosis of ET were applied to define the neurophysiologic examination as compatible or not compatible with ET (all criteria must be present): (1) rhythmic burst of postural tremor on EMG; (2) tremor frequency greater than or equal to 4 Hz; (3) absence of rest tremor or, if present, frequency 1.5 Hz lower than the postural tremor; (4) absence of tremor latency from rest to postural position; (5) changes of the dominant frequency peak less or equal to 1 Hz after the weight load test; and (6) no changes in tremor amplitude after mental concentration. The neurophysiologic criteria for ET showed a sensitivity of 97.7%, a specificity of 82.3%, a positive predictive value of 95.1%, a negative predictive value of 91.1%, and positive probability ratio of 5.5. The odds ratio was 198.43 (95% CI, 66.03 to 596.35). For the diagnosis of ET in patients with postural tremor, routine neurophysiologic tests have high diagnostic and predictive value that justifies its practice in movement disorders clinics.

The combined investigation of the flame dynamics of an industrial gas turbine combustor using high-speed imaging and an optically integrated data collection method

In this paper, innovative investigation of the flame dynamics of an industrial gas turbine combustor using high-speed imaging and flame luminosity measurement has been reported. Both digital and optical integration methods have been applied to study the flame dynamics of an unstable combustion mode, which has a fixed peak frequency around 105 Hz. It is found that the light emission of the seeded combustion possesses the same dominant peak frequency as the acoustic emission. On the other hand the natural flame light emission failed to match the spectrum of the acoustic emission due to signal drop-out, which is a common problem for direct imaging of unseeded flame. The paper has demonstrated that the transition from stable to unstable combustion could be captured successfully by high-speed imaging using a pre-trigger mode. Three stages of transition from stable combustion mode to unstable mode have been identified. In stage one, the flame luminosity and fluctuation increased gradually, which could be assumed as the incipiency of the instability. In stage two, there was a sudden and sharp burst in flame luminosity, which indicates that the combustion process was becoming very intense in the middle of transition. In the third stage, the drastic flame luminosity dissipated slightly and oscillated with constant amplitude and the combustion locked to unstable combustion mode. The two applied techniques have been cross-checked with reference to the unique peak frequency observed.

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

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

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

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