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We developed a low-vibrational-noise cooling configuration using continuous liquefaction of evaporated helium gas from a multi-channel SQUID gradiometer system for whole-head magnetoencephalography (MEG) measurements. The initial reduction of the vibration of the cryocooler was done by rigidly mounting the remote motor and cold head chamber on a concrete wall. This significantly reduces transmission of vibrations to the transfer tube, especially compared with mounting them on vertical aluminum frames. In addition, to reduce vibrations from a mechanical SQUID array insert, we completely eliminated it by mounting each SQUID gradiometer separately on the helmet surface within the vacuum space. Thus, vibrations from the boiling liquid helium and transmission from the transfer tube were both greatly reduced. Magnetic field noise of the 150-channel SQUID gradiometer system showed that the vibration-induced interference peaks are comparable in amplitude to those from a conventional MEG system without helium reliquefaction.

Vibrotactile technology has been gaining increasing interest for effective human-computer communication in various applications. In addition to psychophysical approaches commonly used to study tactile vibrations, neurocognitive responses to vibrotactile stimuli can provide new insights into mechanisms underlying human vibrotactile perception. In this study, we developed a magnetoencephalography (MEG)-compatible vibrotactile stimulation device based on a polyvinyl chloride (PVC) gel actuator to study neuromagnetic somatosensory responses. A symmetric, double-layered PVC gel structure was applied to minimize the magnetic noise from the actuator. The device was used to generate sinusoidal stimuli at high frequencies to activate mechanoreceptors responsible for high-frequency vibrations greater than 50 Hz, and this device showed very little variability in stimulation onset time from the displacement measurements. We successfully observed vibrotactile-evoked magnetic fields by analyzing whole-head MEG data recorded during the high-frequency vibrotactile stimulation of the fingertips. Prominent peak responses were observed at approximately 56 ms (M50) in the contralateral hemisphere and at approximately 100 ms (M100) in both hemispheres. We identified the activation of contralateral primary somatosensory areas as a source of the vibrotactile M50 response. These results demonstrate the feasibility of using our new device to study vibrotactile perception with neuromagnetic imaging methods.

Magnetoencephalography (MEG) is a functional neuroimaging technique that noninvasively detects the brain magnetic field from neuronal activations. Conventional MEG measures brain signals using superconducting quantum interference devices (SQUIDs). SQUID-MEG requires a cryogenic environment involving a bulky non-magnetic dewar and the consumption of liquid helium, which restricts the variability of the sensor array and the gap between the cortical sources and sensors. Recently, miniature optically pumped magnetometers (OPMs) have been developed and commercialized. OPMs do not require cryogenic cooling and can be placed within millimeters from the scalp. In the present study, we arranged six OPM sensors on the temporal area to detect auditory-related brain responses in a two-layer magnetically shielded room. We presented the auditory stimuli of 1-kHz pure-tone bursts with 200-ms duration and obtained the M50 and M100 components of auditory evoked fields. We delivered the periodic stimuli with a 40-Hz repetition rate and observed the gamma-band power changes and inter-trial phase coherence of auditory steady-state responses at 40 Hz. We found that the OPM sensors have a performance comparable to that of conventional SQUID-MEG sensors, and our results suggest the feasibility of using OPM sensors for functional neuroimaging and brain–computer interface applications.

The somatic marker hypothesis proposes that the cortical representation of visceral signals is a crucial component of emotional processing. No previous study has investigated the information flow among brain regions that process visceral information during emotional perception. In this magnetoencephalography study of 32 healthy subjects of either sex, heartbeat-evoked responses (HERs), which reflect the cortical processing of heartbeats, were modulated by the perception of a sad face. The modulation effect was localized to the prefrontal cortices, the globus pallidus, and an interoceptive network including the right anterior insula (RAI) and dorsal anterior cingulate cortex (RdACC). Importantly, our Granger causality analysis provides the first evidence for the increased flow of heartbeat information from the RAI to the RdACC during sad face perception. Moreover, using a surrogate R-peak analysis, we have shown that this HER modulation effect was time-locked to heartbeats. These findings advance the understanding of brain-body interactions during emotional processing.

Background: In recent years, vibrotactile haptic feedback technology has been widely used for user interfaces in the mobile devices. Although functional neuroimaging studies have investigated human brain responses to different types of tactile inputs, the neural mechanisms underlying high-frequency vibrotactile perception are still relatively unknown. Our aim was to investigate neuromagnetic brain responses to high-frequency vibrotactile stimulation, using magnetoencephalography (MEG). Methods: We measured 152-channel whole-head MEG in 30 healthy, right-handed volunteers (aged 20-28 years, 15 females). A total of 300 vibrotactile stimuli were presented at the tip of either the left index finger or the right index finger in two separate sessions. Sinusoidal vibrations at 150 Hz for 200 ms were generated with random inter-stimulus intervals between 1.6 and 2.4 s. Both time-locked analysis and time-frequency analysis were performed to identify peak responses and oscillatory modulations elicited by high-frequency vibrations. The significance of the evoked and induced responses for dominant and non-dominant hand stimulation conditions was statistically tested, respectively. The difference in responses between stimulation conditions was also statistically evaluated. Results: Prominent peak responses were observed at 56 ms (M50) and at 100 ms (M100) for both stimulation conditions. The M50 response revealed clear dipolar field patterns in the contralateral side with significant cortical activations in the contralateral primary sensorimotor area, whereas the M100 response was not as prominent as the M50. Vibrotactile stimulation induced significant suppression of both alpha (8-12 Hz) and beta (20-30 Hz) band activity during the mid-latency period (0.2-0.4 s), primarily in sensorimotor areas contralateral to the stimulation side. In addition, a significant alpha enhancement effect in posterior regions was accompanied with alpha suppressions in sensorimotor regions. The alpha suppression was observed in a broader distribution of cortical areas for the non-dominant hand stimulation. Conclusion: Our data demonstrate that high-frequency tactile vibrations, which is known to primarily activate Pacinian corpuscles, elicit somatosensory M50 and M100 responses in the evoked fields and induce modulations of alpha and beta band oscillations during mid-latency periods. Our study is also consistent with that the primary sensorimotor area is significantly involved in the processing of high-frequency vibrotactile information with contralateral dominance.

Recently, an increasing number of studies have employed multivariate pattern analysis (MVPA) rather than univariate analysis for the dynamic pattern decoding of event-related responses recorded with a MEG/EEG sensor. The use of the MVPA approach for source-reconstructed MEG/EEG data is uncommon. For these data, we need to consider the source orientation information and the signal leakage among brain regions. In the present study, we evaluate the perspective of the MVPA approach in the context of source orientation information and signal leakage in source-reconstructed MEG data. We perform face vs. tool object category decoding (FvsT-OCD) of event-related responses from single or multiple voxels from a brain region using a univariate analysis approach and/or the MVPA approach. We also propose and perform symmetric signal leakage correction of source-reconstructed data using an independent component analysis-based approach. FvsT-OCD using single voxel information shows higher sensitivity for the MVPA approach than univariate analysis, as the MVPA approach efficiently utilizes information on all three dipole orientations and is less affected by inter-subject variability. The MVPA approach shows higher sensitivity for FvsT-OCD when considering information from multiple voxels than for a single voxel in a brain region. This finding suggests that the MVPA approach captures the latent multivoxel distributed pattern. However, the results may be partly or entirely attributable to signal leakage between brain regions, as the sensitivity is substantially reduced after signal leakage correction. A consideration of signal leakage is therefore essential during the evaluation of MVPA outcomes.

Thermoreception is an important cutaneous sense, which plays a role in the maintenance of our body temperature and in the detection of potential noxious heat stimulation. In this study, we investigated event‐related fields (ERFs) and neural oscillatory activities, which were modulated by warmth stimulation. We developed a warmth stimulator that could elicit a warmth sensation, without pain or tactile sensation, by using a deep‐penetrating 980‐nm diode laser. The index finger of each participant (n = 24) was irradiated with the laser warmth stimulus, and the cortical responses were measured using magnetoencephalography (MEG). The ERFs and oscillatory responses had late latencies (∼1.3 s and 1.0–1.5 s for ERFs and oscillatory responses, respectively), which could be explained by a slow conduction velocity of warmth‐specific C‐fibers. Cortical sources of warmth‐related ERFs were seen in the bilateral primary and secondary somatosensory cortices (SI and SII), posterior part of the anterior cingulate cortex (pACC), ipsilateral primary motor, and premotor cortex. Thus, we suggested that SI, SII, and pACC play a role in processing the warmth sensation. Time–frequency analysis demonstrated the suppression of the alpha (8–13 Hz) and beta (18–23 Hz) band power in the bilateral sensorimotor cortex. We proposed that the suppressions in alpha and beta band power are involved in the automatic response to the input of warmth stimulation and sensorimotor interactions. The delta band power (1–4 Hz) increased in the frontal, temporal, and cingulate cortices. The power changes in delta band might be related with the attentional processes during the warmth stimulation.

Background When many features and a small number of clinical data exist, previous studies have used a few top-ranked features from the Fisher's discriminant ratio (FDR) for feature selection. However, there are many similarities between selected features. New method: To reduce the redundant features, we applied a technique employing FDR in conjunction with feature correlation. We performed an attention network test on schizophrenic patients and normal subjects with a 152-channel magnetoencephalograph. P300m amplitudes of event-related fields (ERFs) were used as features at the sensor level and P300m amplitudes of ERFs for 500 nodes on the cortex surface were used as features at the source level. Features were ranked using FDR criterion and cross-correlation measure, and then the highest ranked 10 features were selected and an exhaustive search was used to find combination having the maximum accuracy. Results At the sensor level, we found a single channel of the occipital region that distinguished the two groups with an accuracy of 89.7 %. At source level, we obtained an accuracy of 96.2 % using two features, the left superior frontal region and the left inferior temporal region. Comparison with existing method At source level, we obtained a higher accuracy than traditional method using only FDR criterion (accuracy = 88.5 %). We used only the P300 m amplitude (not latency) on a single channel and two brain regions at a fairly high rate.

Pexa-Vec (JX-594) is a specific cancer-targeted oncolytic and immunotherapeutic vaccinia virus. The purpose of this study was to develop methods to maximize the stability of Pexa-Vec. In short-term instability testing, viral activity was rapidly decreased both at 4°C and at room temperature (RT), but it was completely restored after sonication followed by vortex. Long-term stability testing of Pexa-Vec in the following liquid formulations was performed: (A) 30 mM Tris/pH 7.6, (B) 30 mM Tris/pH 8.6,(C) 30 mM Tris/pH 7.6, 150 mM NaCl, 15% sucrose, (D) 30 mM Tris/pH 7.6, 15% sucrose, and (E) 30 mM Tris/pH 8.6, 15% sucrose. Viral activity decreased less than 2 log10 at 4°C, and RT was observed in 3 days in B, while viral activity was not decreased even after 4–8 weeks at 4°C and at 1 week in RT in A, suggesting that neutral pH may be essential to maintain virus stability. The addition of 15% sucrose into A (D) significantly increased viral stability at -20°C, 4°C, or RT, and it was also observed at pH 8.6 (E). The addition of 150 mM NaCl into D (C) significantly increased viral stability in addition to the sucrose effect at 4°C or RT. Accordingly, the viral activity in formulation C was maintained for 1.5 years at 4°C, and for 1-2 weeks in RT. In conclusion, we propose that formulation C can provide the most adequate condition for the proper storage of vaccinia oncolytic virus.

[Image: see text] COVER ILLUSTRATION During warmth sensation, the activation in the primary somatosensory cortex (SI) currently remains controversial in the EEG and fMRI studies. This magnetoencephalographic (MEG) study investigated cortical responses to purewarmth stimuli, using a 980‐nm diode laser irradiation. The sources of event‐related fields, alpha and beta oscillatory changes were found in SI. For details, see An et al.Magnetoencephalographic study of event‐related fields and cortical oscillatory changes during cutaneous warmth processing in this issue.

Recently, neurophysiological findings about social interaction have been investigated widely, and hardware has been developed that can measure multiple subjects' brain activities simultaneously. These hyperscanning studies have enabled us to discover new and important evidences of interbrain interactions. Yet, very little is known about verbal interaction without any visual input. Therefore, we conducted a new hyperscanning study based on verbal, interbrain turn-taking interaction using simultaneous EEG/MEG, which measures rapidly changing brain activities. To establish turn-taking verbal interactions between a pair of subjects, we set up two EEG/MEG systems (19 and 146 channels of EEG and MEG, respectively) located ∼100 miles apart. Subjects engaged in verbal communication via condenser microphones and magnetic-compatible earphones, and a network time protocol synchronized the two systems. Ten subjects participated in this experiment and performed verbal interaction and noninteraction tasks separately. We found significant oscillations in EEG alpha and MEG alpha/gamma bands in several brain regions for all subjects. Furthermore, we estimated phase synchronization between two brains using the weighted phase lag index and found statistically significant synchronization in EEG and MEG data. Our novel paradigm and neurophysiological findings may foster a basic understanding of the functional mechanisms involved in human social interactions. Hum Brain Mapp 39:171-188, 2018. © 2017 Wiley Periodicals, Inc.

Developing Magnetoencephalography (MEG) based on Superconducting Quantum Interference Device (SQUID) facilitates to observe the human brain functions in non-invasively and high temporal and high spatial resolution. By using this MEG, we studied alpha rhythm (8-13 Hz) that is one of the most predominant spontaneous rhythm in human brain. The 8–13 Hz rhythm is observed in several sensory region in the brain. In visual related region of occipital, we call to alpha rhythm, and auditory related region of temporal call to tau rhythm, sensorimotor related region of parietal call to mu rhythm. These rhythms are decreased in task related region and increased in task irrelevant regions. This means that these rhythms play a pivotal role of inhibition in task irrelevant region. It may be helpful to attention to the task. In several literature about the alpha-band inhibition in multi-sensory modality experiment, they observed this effect in the occipital and somatosensory region. In this study, we hypothesized that we can also observe the alpha-band inhibition in the auditory cortex, mediated by the tau rhythm. Before that, we first investigated the existence of the alpha and tau rhythm in occipital and temporal region, respectively. To see these rhythms, we applied the visual and auditory stimulation, in turns, suppressed in task relevant regions, respectively.

To study the relationship between the varying degrees of cognitive load and long-range synchronization among neural networks, we utilized a dual-task paradigm combining concurrent word recall working memory tasks and oculomotor tasks that differentially activate the common frontoparietal (FP) network. We hypothesized that each dual-task combination would generate differential neuronal activation patterns among long-range connection during word retention period. Given that the FP alpha-phase synchronization is involved in attentional top-down processes, one would expect that the long-range synchronization pattern is affected by the degrees of dual-task demand. We measured a single-trial phase locking value in the alpha frequency (8-12 Hz) with electroencephalography in healthy participants. Single-trial phase locking value characterized the synchronization between two brain signals. Our results revealed that different amounts of FP alpha-phase synchronization were produced by different dual-task combinations, particularly during the early phase of the word retention period. These differences were dependent on the individual's working memory capacity and memory load. Our study shows that during dual-task, each oculomotor task, which is subserved by distinct neural network, generates different modulation patterns on long-range neuronal activation and FP alpha-phase synchronization seems to reflect these differential cognitive loads.

Background and PurposezzThe aim of this study was to determine the usefulness of threedimensional (3D) scalp EEG source imaging (ESI) in partial epilepsy in comparison with the results of presurgical evaluation, magnetoencephalography (MEG), and electrocorticography (ECoG). MethodszzThe epilepsy syndrome of 27 partial epilepsy patients was determined by presur gical evaluations. EEG recordings were made using 70 scalp electrodes, and the 3D coordinates of the electrodes were digitized. ESI images of individual and averaged spikes were analyzed by Curry software with a boundary element method. MEG and ECoG were performed in 23 and 9 patients, respectively. ResultszzESI and MEG source imaging (MSI) results were well concordant with the results of presurgical evaluations (in 96.3% and 100% cases for ESI and MSI, respectively) at the lobar level. However, there were no spikes in the MEG recordings of three patients. The ESI re sults were well concordant with MSI results in 90.0% of cases. Compared to ECoG, the ESI results tended to be localized deeper than the cortex, whereas the MSI results were generally localized on the cortical surface. ESI was well concordant with ECoG in 8 of 9 (88.9%) cases, and MSI was also well concordant with ECoG in 4 of 5 (80.0%) cases. The EEG single dipoles in one patient with mesial temporal lobe epilepsy were tightly clustered with the averaged dipole when a 3 Hz high-pass filter was used. ConclusionszzThe ESI results were well concordant with the results of the presurgical evalua tion, MSI, and ECoG. The ESI analysis was found to be useful for localizing the seizure focus and is recommended for the presurgical evaluation of intractable epilepsy patients. Key Wordszz partial epilepsy, EEG source imaging, MEG source imaging, source localization, presurgical evaluation, epilepsy surgery.

Computation of headmodel and sourcemodel from the subject's MRI scan is an essential step for source localization of magnetoencephalography (MEG) (or EEG) sensor signals. In the absence of a real MRI scan, pseudo MRI (i.e., associated headmodel and sourcemodel) is often approximated from an available standard MRI template or pool of MRI scans considering the subject's digitized head surface. In the present study, we approximated two types of pseudo MRI (i.e., associated headmodel and sourcemodel) using an available pool of MRI scans with the focus on MEG source imaging. The first was the first rank pseudo MRI; that is, the MRI scan in the dataset having the lowest objective registration error (ORE) after being registered (rigid body transformation with isotropic scaling) to the subject's digitized head surface. The second was the averaged rank pseudo MRI that is generated by averaging of headmodels and sourcemodels from multiple MRI scans respectively, after being registered to the subject's digitized head surface. Subject level analysis showed that the mean upper bound of source location error for the approximated sourcemodel in reference to the real one was 10 ± 3 mm for the averaged rank pseudo MRI, which was significantly lower than the first rank pseudo MRI approach. Functional group source response in the brain to visual stimulation in the form of event-related power (ERP) at the time latency of peak amplitude showed noticeably identical source distribution for first rank pseudo MRI, averaged rank pseudo MRI, and real MRI. The source localization error for functional peak response was significantly lower for averaged rank pseudo MRI compared to first rank pseudo MRI. We conclude that it is feasible to use approximated pseudo MRI, particularly the averaged rank pseudo MRI, as a substitute for real MRI without losing the generality of the functional group source response.

Magnetoencephalography (MEG) based on superconducting quantum interference devices enables the measurement of very weak magnetic fields (10-1000 fT) generated from the human or animal brain. In this article, we introduce a small MEG system that we developed specifically for use with rats. Our system has the following characteristics: (1) variable distance between the pick-up coil and outer Dewar bottom (∼5 mm), (2) small pick-up coil (4 mm) for high spatial resolution, (3) good field sensitivity (45∼ 80fT/cm/Hz), (4) the sensor interval satisfies the Nyquist spatial sampling theorem, and (5) small source localization error for the region to be investigated. To reduce source localization error, it is necessary to establish an optimal sensor layout. To this end, we simulated confidence volumes at each point on a grid on the surface of a virtual rat head. In this simulation, we used locally fitted spheres as model rat heads. This enabled us to consider more realistic volume currents. We constrained the model such that the dipoles could have only four possible orientations: the x- and y-axes from the original coordinates, and two tangentially layered dipoles (local x- and y-axes) in the locally fitted spheres. We considered the confidence volumes according to the sensor layout and dipole orientation and positions. We then conducted a preliminary test with a 4-channel MEG system prior to manufacturing the multi-channel system. Using the 4-channel MEG system, we measured rat magnetocardiograms. We obtained well defined P-, QRS-, and T-waves in rats with a maximum value of 15 pT/cm. Finally, we measured auditory evoked fields and steady state auditory evoked fields with maximum values 400 fT/cm and 250 fT/cm, respectively.

Recently, neurophysiological findings about social interaction have been investigated widely, and hardware has been developed that can measure multiple subjects' brain activities simultaneously. These hyperscanning studies have enabled us to discover new and important evidences of interbrain interactions. Yet, very little is known about verbal interaction without any visual input. Therefore, we conducted a new hyperscanning study based on verbal, interbrain turn‐taking interaction using simultaneous EEG/MEG, which measures rapidly changing brain activities. To establish turn‐taking verbal interactions between a pair of subjects, we set up two EEG/MEG systems (19 and 146 channels of EEG and MEG, respectively) located ∼100 miles apart. Subjects engaged in verbal communication via condenser microphones and magnetic‐compatible earphones, and a network time protocol synchronized the two systems. Ten subjects participated in this experiment and performed verbal interaction and noninteraction tasks separately. We found significant oscillations in EEG alpha and MEG alpha/gamma bands in several brain regions for all subjects. Furthermore, we estimated phase synchronization between two brains using the weighted phase lag index and found statistically significant synchronization in EEG and MEG data. Our novel paradigm and neurophysiological findings may foster a basic understanding of the functional mechanisms involved in human social interactions. Hum Brain Mapp 39:171–188, 2018. © 2017 Wiley Periodicals, Inc.

SUMMARY As sensitive magnetic sensors, magnetometers based on superconducting quantum interference devices can be used for the detection of weak magnetic fields. These signals can be generated by diverse origins, for example, brain electric activity, myocardium electric activity, and nuclear precession of hydrogen protons. In addition, weak current induced in the low-temperature detectors, for example, transition-edge sensors can be detected using SQUIDs. And, change of magnetic flux quantum generated in a superconducting ring can be detected by SQUID, which can be used for realization of mechanical force. Thus, SQUIDs are key elements in precision metrology. In Korea, development of low-temperature SQUIDs based on Nb-Josephson junctions was started in late 1980s, and Nb-based SQUIDs have been used mainly for biomagnetic measurements; magnetocardiography and magnetoencephalography. High-Tc SQUIDs, being developed in mid 1990s, were used for magnetocardiography and nondestructive evaluation. Recently, SQUID-based low-field nuclear magnetic resonance technology is under development. In this paper, we review the past progress and recent activity of SQUID applications in Korea, with focus on biomagnetic measurements.

// Nam Hee Lee 1, 2 , Mikyung Kim 1 , Sung Yong Oh 3 , Seong-Geun Kim 4 , Hyuk-Chan Kwon 1 , Tae-Ho Hwang 5, 6 1 SillaJen, Inc., Busan, Korea 2 Department of Physiology, Pusan National University, School of Medicine, Yangsan, Korea 3 Department of Internal Medicine, Dong-A University College of Medicine, Busan, Korea 4 Department of Internal Medicine, Pusan National University Yangsan Hospital, Yangsan, Korea 5 Department of Pharmacology, Pusan National University, School of Medicine, Yangsan, Korea 6 Gene and Cell Therapy Research Center for Vessel-associated Diseases, School of Medicine, Pusan National University, Yangsan, Korea Correspondence to: Tae-Ho Hwang, email: thhwang@pusan.ac.kr Hyuk-Chan Kwon, email: hckwon@sillajen.com Keywords: oncolytic virus, gene expression profiling, hematologic malignancy Received: August 20, 2016 Accepted: November 04, 2016 Published: November 25, 2016 ABSTRACT Pexa-Vec (pexastimogene devacirpvec; JX-594) has emerged as an attractive tool in oncolytic virotherapy. Pexa-Vec demonstrates oncolytic and immunotherapeutic mechanisms of action. But the determinants of resistance to Pexa-Vec are mostly unknown. We treated hemoatologic malignant cells with Pexa-Vec and examined the gene-expression pattern of sensitive and resistant cells. Human myeloid malignant cell lines (RPMI-8226, IM-9, K562, THP-1) and lymphoid cancer cell lines (MOLT4, CCRF-CEM, Ramos, U937) were treated with Pexa-Vec. Pexa-Vec was cytotoxic on myeloid cell lines in a dose-dependent manner, and fluorescent imaging and qPCR revealed that Pexa-Vec expression was low in RAMOS than IM-9 after 24 hrs and 48 hrs of infection. Gene expression profiles between two groups were analyzed by microarray. Genes with at least 2-fold increase or decrease in their expression were identified. A total of 660 genes were up-regulated and 776 genes were down-regulated in lymphoid cancer cell lines. The up- and down-regulated genes were categorized into 319 functional gene clusters. We identified the top 10 up-regulated genes in lymphoid cells. Among them three human genes (LEF1, STAMBPL1, and SLFN11) strongly correlated with viral replication. Up-regulation of PVRIG, LPP, CECR1, Arhgef6, IRX3, IGFBP2, CD1d were related to resistant to Pexa-Vec. In conclusion, lymphoid malignant cells are resistant to Pexa-Vec and displayed up-regulated genes associated with resistance to oncolytic viral therapy. These data provide potential targets to overcome resistance, and suggest that molecular assays may be useful in selecting patients for further clinical trials with Pexa-Vec.

Phase-amplitude coupling (PAC) plays an important role in neural communication and computation. Interestingly, recent studies have indicated the presence of ubiquitous PAC phenomenon even during the resting state. Despite the importance of PAC phenomenon, estimation of significant physiological PAC is challenging because of the lack of appropriate surrogate measures to control false positives caused by non-physiological PAC. Therefore, in the present study, we evaluated PAC phenomenon during resting-state magnetoencephalography (MEG) signal and considered various surrogate measures and computational approaches widely used in the literature in addition to proposing new ones. We evaluated PAC phenomenon over the entire length of the MEG signal and for multiple shorter time segments. The results indicate that the extent of PAC phenomenon mainly depends on the surrogate measures and PAC computational methods used, as well as the evaluation approach. After a careful and critical evaluation, we found that resting-state MEG signals failed to exhibit ubiquitous PAC phenomenon, contrary to what has been suggested previously.

The aim of this study was to investigate the surgical and oncologic outcomes of laparoscopy-assisted gastrectomy (LAG) and open gastrectomy (OG) for advanced gastric cancer (AGC) using the case-control method with a sufficient follow-up period.The authors retrospectively analyzed 89 patients who underwent LAG and 345 patients who underwent OG for AGC between August 1999 and June 2007. A total of 176 matched cases were included in the final analysis.Except for tumor size and reconstruction, there were no statistically significant differences in the clinicopathological parameters between the two groups. Although operation time was significantly longer for LAG than OG (228.3 vs. 183.6 min, p0.0001), first flatus time and postoperative hospital stay without complications were significantly shorter in the LAG group (3.2 vs. 3.7 days, p0.0001; 7.0 vs. 10.4 days, p0.0001, respectively). Operation-related complications occurred in 7 cases (8.0%) in both groups. 13 patients (14.8%) in the LAG group and 15 patients (17.1%) in the OG group had recurrence. There was no statistically significant difference in the 5-year and disease-free survival rates between LAG and OG.LAG for AGC might be considered to be a minimally invasive surgery in some selected cases, although a well-designed prospective study comparing LAG with OG for AGC is needed.

The objective of this study was to determine whether the expressions of the excision cross-complementing (ERCC1), thymidylate synthase (TS) and glutathione S-transferase P1 (GSTP1) are predictive of clinical outcomes in advanced gastric cancer (AGC) patients receiving treatment with adjuvant 5-fluorouracil (5-FU) and cisplatin (FP) chemotherapy. One hundred forty nine patients were included in this study. ERCC1 and GSTP1 expression was correlated significantly with tumor size (p = 0.040, p = 0.018, respectively). Stage and positive lymph node ratio were associated independently with disease free survival (DFS) and overall survival (OS). Both ERCC1 and GSTP1 expression had a significant impact on OS (hazard ratio = 0.069, p = 0.021). TS expression was not related to DFS and OS.

Background: Accurate identification of patients with acute coronary syndrome (ACS) is often difficult especially when an electrocardiogram (ECG) does not show typical elevation of ST segment. The aim of the present study was therefore to evaluate the efficacy of magnetocardiography (MCG) for diagnosis of ACS in patients with acute chest pain presenting without ST segment elevation. Methods and Results: In the present retrospective study 364 patients with the suspected ACS without ST segment elevation were selected. Significant coronary artery disease (CAD) was defined as a stenosis ≥50% in at least one of 16 segments of the 3 major coronary arteries and their branches. The MCG recordings were obtained at resting state using a 64-channel MCG system in a magnetically shielded room. The patients were classified on the basis of the probability distribution. The presence of significant CAD was identified with a sensitivity of 84.0% and a specificity of 85.0%, compared to 44.7% and 89.8% on ECG. In the subgroup of patients without specific findings on ECG or biomarker test, MCG had a sensitivity of 73.5% and a specificity of 82.3%. Conclusions: MCG was acceptably sensitive and specific in identifying patients with ACS even in the absence of specific findings on ECG and positive biomarker tests. Thus, MCG seems beneficial for the early triage of patients with acute chest pain. (Circ J 2010; 74: 1424 - 1430)

Magnetocardiography (MCG) using a superconducting quantum interference device (SQUID) sensor has been known for a noninvasive, noncontact, and safe diagnostic tool to detect ischemic heart disease such as angina and myocardial infarction. The magnetic distribution generated by the electrical activation of the heart reveals the abnormality of the myocardial status. The bust depth of people in 20s and 70s are much different, and the greatest difference is up to 154 mm. The purpose of this study is to identify whether MCG signals and parameter values are changed at the different locations of the SQUID sensor assembly. It would be an important reference for the standard measurement. Four healthy male subjects (33.3 plusmn 6.3 years) participated in this study. The distance between the chest surface and the bottom of the sensor assembly was 20, 40, 60, and 80 mm. Recording was made using 64-channel MCG system (axial type, first-order gradiometer) developed by Korea Research Institute of Standards and Science (KRISS). MCG were recorded for 30 s in a magnetically shielded room. As the sensor location is getting away from the chest surface, the each mean amplitude of R- and T-wave peak decreases to 70% (at 40-mm distance), 51% and 50% (at 60 mm), and 38% and 35% (at 80 mm) of the reference amplitude measured at 20-mm distance (y = -0.000002*x 3 + 0.0003*x 2 - 0.0308*x + 1.4961, R 2=1.00; where y= average amplitude remained after reduction}, x = distance between the chest surface and sensor location). Interindividual difference was less than 5%. The regression equations may be used as a good reference to calculate how much strength will be decreased by the distance. In MCG parameters, most parameters decreased when the distance increased. As an example, the current moment at T-wave peak reduced to 52% (at 40-mm distance), 33% (at 60 mm), and 19% (at 80 mm). Results showed how MCG signal and parameter values decreased rapidly when the sensor assembly was located far from the signal source. The study results may be used as a useful reference to design MCG system and analysis program.

Background: The aim of this study was to determine whether the expression of the excision repair cross-complementing 1 (ERCC1), thymidylate synthase (TS) and glutathione S-transferase IT (GSTπ) predict clinical outcome in patients with advanced colorectal cancer treated with fluorouracil (5-FU)/ oxaliplatin chemotherapy. Methods: The study population consisted of 70 patients with advanced colorectal cancer (median age, 54 years). Patients were treated with oxaliplatin 85 mg/m 2 as a 2-hour infusion on days 1 plus leucovorin (LV) 20 mg/m 2 over 10 minutes, followed by 5-FU bolus 400 mg/m 2 and a 22-hour continuous infusion of 600 mg/m 2 from day 1 to 2. Treatment was repeated at 2-week intervals. The expression of ERCC1, TS, and GSTπ in primary tumors was examined using immunohistochemistry. Results: ERCC1, TS, and GSTπ were positive in 55.7%, 68.6%, and 71.4% of cases, respectively. Patients without TS expression were more likely to respond to chemotherapy (P = 0.009). There were no significant differences between response to treatment and the ERCC 1 or GSTπ expression pattern (P = 0.768, P = 0.589, respectively). The median overall survival (OS) was significantly longer in patients without ERCC1 expression (P = 0.0474). Patients who were ERCC 1 positive combined with TS positive, or those with ERCC1 positive combined with TS positive and GSTπ positive had a poor OS (P = 0.0017, P = 0.0323, respectively). Multivariate analysis revealed that both ERCC1 and TS expression significantly impacted OS (hazard ratio 1.72, P = 0.023). Conclusion: Immunohistochemical study of ERCC1 and TS may be useful for the prediction of clinical outcome in patients with advanced colorectal cancer treated with 5-FU and oxaliplatin.

Electrophysiologic information as well as anatomic information to detect coronary artery disease is important for accurate diagnosis. A diagnostic tool that can detect patients with unstable angina pectoris (UAP) or non-ST elevation myocardial infarction (NSTEMI) with severe stenosis would be beneficial for patients and clinicians. Magnetocardiography has been recognized as a noncontact, noninvasive, fast tool to detect ischemic coronary artery disease and provide direct electrophysiologic information from the heart. In this study, 10 magnetocardiographic (MCG) parameters from 4 groups, including 185 young controls, 19 age-matched controls (AMCs), 110 patients with UAP, and 83 patients with NSTEMIs, were analyzed. A 64-channel MCG system in a magnetically shielded room was used. All 10 parameters showed significant differences (p

Although there have been many reports regarding clinical outcomes of endoscopic treatment for early gastric cancer (EGC), little is known about detection of recurrence after endoscopic submucosal dissection (ESD). This study aims to clarify the clinical value of serological marker or imaging tools, including conventional CT and PET-CT scans, in detecting recurrent gastric cancer after ESD in Korea.From July 2004 to March 2008, 212 patients who had received ESD for EGC were enrolled in the study. For preoperative staging, conventional CT and PET-CT scans were performed in 141 patients, and for detection of recurrence of cancer, conventional CT, PET-CT scans and tumour marker; CEA, CA19-9, AFP were checked in 165 patients.The local recurrence rate was 4.7% (10/212) during the study period. At 9 months after endoscopic treatment, 3 cases recurred. Four showed recurrence at 12 months, 2 at 18 months and 1 at 24 months. The positive rate was 7.1% (10/141) in conventional CT and 0% (0/24) in PET-CT scans for preoperative staging. Conventional CT and PET-CT scans could not detect local recurrence of cancer during the follow-up period. Tumour markers did not show any significant correlation with recurrence of cancer.The study suggests that conventional CT, PET-CT scans and tumour marker have no role in the primary surveillance of early gastric cancer and/or in detecting recurrence after endoscopic treatment. For early diagnosis of recurrence after endoscopic treatment, a biopsy specimen from the endoscopic examination has to be obtained at regular intervals.

OBJECTIVE. Endoscopic submucosal dissection (ESD) of gastric neoplasia has been reported to have a higher bleeding rate than conventional endoscopic mucosal resection (EMR). The aim of this study was to identify the risk factors for bleeding associated with ESD. MATERIAL AND METHODS. The records of consecutive patients who underwent ESD for gastric adenoma/early gastric cancer were reviewed. Potential risk factors included patient age, lesion size, gross findings, location, and histology of the tumor. The primary end-point was the incidence of immediate or delayed bleeding related to ESD. RESULTS. A total of 144 patients were studied; bleeding occurred in 32 cases (22.2%) with immediate bleeding in 29 cases. Delayed bleeding (3 cases) occurred at day 2 (2 patients) and at day 7 in 1 patient. In all cases of immediate bleeding, immediate hemostatic therapy was successful. The histology of tumor was the only factor that was statistically significantly associated with bleeding (adjusted hazard ratio 6.770, 95% confidence interval 1.830-25.048, p=0.004). CONCLUSIONS. The only factor that correlated with an increased risk of bleeding with ESD was the presence of gastric malignancy. We found no factor that would, prospectively, be amenable to prevention of bleeding.

Background Magnetocardiography (MCG) is a new noninvasive modality for recording cardiac depolarization and repolarization and was used in the present study to evaluate abnormalities in patients with Brugada syndrome (BS). Methods and Results The MCG findings of 10 BS, 21 right bundle branch block (RBBB), and 34 normal patients were compared. On the horizontal spatiotemporal activation graph (STAG), the r' waves were more frequently located on the right side in the RBBB than in the normal (p=0.001) or BS groups (p=0.001). The maximum current angles of the r' wave fell into the northwest axis in all BS patients as compared to having a right axis deviation in 19 of 21 RBBB patients (90.4%, p=0.001). In the magnetic field and current density vector maps during late repolarization, the BS group had a non-dipole pattern more frequently and a higher number of poles compared with the normal (p=0.001) and RBBB groups (p=0.001). Conclusions During depolarization, the horizontal STAG location and maximum current angle of the r' wave were beneficial in differentiating BS from RBBB and normal. The magnetic dispersion was a more frequently observed finding in BS patients than in RBBB and normal patients during late repolarization. (Circ J 2008; 72: 94 - 101)

A 64-channel planar gradiometer system was developed to measure magnetocardiogram (MCG) signals. The planar gradiometers are second-order planar gradiometers with a baseline of 50 mm, fabricated from Nb thin films on Si wafers using thin film processes. The SQUIDs were fabricated from Nb/Al-oxide/Nb junctions, and a double relaxation oscillation SQUID (DROS) scheme was used to have a large flux-to-voltage transfer, typically about 1 mV/Phi0. The planar gradiometers were arranged to measure magnetic field components tangential to the chest surface, which has a field distribution peak just above the current dipole. The diameter of the sensor coverage area is 190 mm, which was proved to be large enough to provide MCG field distribution in a single measurement. Inside a thin-wall shield room, the white noise level of the planar gradiometer system is about 8 fTradicHz. The 64-channel system was operated in a thin-wall shield room, and MCG signals were measured.

We fabricated multichannel magnetocardiogram (MCG) systems of 1 magnetometer type and 2 planar gradiometer types, and compared the MCG data measured using different pickup coil systems. The magnetometer type is a 61-channel magnetometer system measuring vertical component of MCG fields. The magnetometers were integrated magnetometer structure with the pickup coil and SQUID fabricated on the same wafer. The two planar gradiometer systems are 64-channel planar gradiometer systems of first-order with a baseline of 4 cm, and of second-order with a baseline of 5 cm. The planar gradiometer systems are measuring field components tangential to the chest surface. The MCG waveforms and field distributions were measured on the same subject using the 3 MCG systems of different pickup coil types. The measured field distributions and waveforms were transformed into data of other pickup coil types, and the comparison between the measured and transformed results were done.

A double relaxation oscillation SQUID with a reference junction (RJ-DROS) already has a fixed reference current, so that it holds a fixed flux-to-voltage characteristics when fabricated. When an additional current flows through the reference junction but not through the signal junction in the RJ-DROS, we have obtained the variation of its characteristics. The additional reference current has an effect on reducing the fixed reference current, which results in changing averaged relaxation voltage and transfer coefficient. In particular, while the critical current of the signal SQUID exceeds the reference current, the averaged relaxation voltage at the reference junction is enlarged by the added bias current combined with an additional current and an initial bias current. Therefore the additional reference current can provide the RJ-DROS with variable modulation depth and width within the operating range. Although the characteristics of RJ-DROSs are fixed differently each to each when they are fabricated, the additional current can adjust their characteristics to the same one, which is useful for controlling DROSs in a multichannel DROS system. However, an input-bias current in the preamplifier detecting the outputs at the reference junction, acts as an additional current, and then makes the reference current shift from the optimum current or deviate from the operating range, the input-bias current needs to be regulated within the operating range

We developed a magnetocardiogram (MCG) system measuring tangential field components using planar gradiometers. The SQUID insert has 64 planar gradiometers, of which 32 measure the x-component and the other 32 measure the y-component, where the chest surface is in the x and y plane. The SQUID sensor is a double relaxation oscillation SQUID type with high flux-to-voltage transfers. Thus, a room-temperature dc preamplifier with a modest input voltage noise could be used to detect the SQUID output voltage directly. The pickup coils are first-order planar gradiometers with a baseline of 4 cm, and they were connected to the input coils using a superconductive bonding of Nb wires. The sensor coverage area of the 64 channels is 190 mm in diameter, and the average boil-off rate of liquid He is 3.6 L/d in everyday operation of the SQUID system. The SQUID operation of the 64 channels was done by digital controls and the average noise of the MCG system was 4.6 fT Hz−1/2 at 100 Hz, inside a magnetically shielded room.