Assessment of safety of self-controlled repetitive trans-vertebral magnetic stimulation

OBJECTIVE

The aim of this study was to assess safety issues of self-controlled repetitive trans-vertebral magnetic stimulation (rTVMS) in humans.

METHODS

We investigated effects of self-controlled rTVMS (≤20 Hz, ≤90% intensity) on vital signs and subjective sensations in 1690 trials of 30 healthy volunteers and 12 patients with spinal cord disorders.

RESULTS

Healthy volunteers and the patients received 4595 ± 2345, and 4450 ± 2304 pulses in one day, respectively. No serious adverse events were observed in any participants, and only minor events were seen as follows. While blood pressure was unaffected in the patients, the diastolic blood pressure increased slightly after rTVMS in healthy volunteers. The peripheral capillary oxygen saturation increased after rTVMS in healthy volunteers. "Pain" or "Discomfort" was reported in approximately 10% of trials in both participants groups. Degree of the evoked sensation positively correlated with stimulus intensity and was affected by the site of stimulation.

CONCLUSION

Self-controlled rTVMS (≤20 Hz and ≤90% intensity) did not induce any serious adverse effects in healthy volunteers and patients with spinal cord disorders.

SIGNIFICANCE

Our results indicate that rTVMS can be used safely in physiological investigations in healthy volunteers and also as treatment for neurological disorders.

A 5-kV pulse generator with a 100-kV/µs slew rate based on series-connected 1700-V SiC MOSFETs for electrical insulation tests

This study demonstrates a high-slew-rate 5-kV pulse generator for electrical insulation tests. Electrical equipment, such as electrical actuators and traction drive motors, are exposed to severe electrical stress because recent switching inverters have high-frequency outputs with high supply voltages using wide-bandgap power devices. For an advanced electrical insulation test, a high-voltage pulse generator is required with a high slew rate; however, such generators suffer from large switching noise, followed by measurement noise, such as ground voltage fluctuations and radiation noise, hindering the detection of partial discharge (PD) phenomena. In this study, we propose a 5-kV pulse generator based on series-connected 1700-V silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). Four 1700-V SiC MOSFETs are connected in series as a 5-kV SiC switching module, constituting a half-bridge configuration for the pulse generator. The obtained switching waveforms exhibit fast rise times of 48 ns under 5 kV and 6.2 ns under 400 V with a low voltage overshoot and ringing owing to superior device characteristics and reduced parasitic inductances. Because of the low switching noise, we detect a clear PD signal with a 1500-V pulse when using the fabricated pulse generator for a PD test of a twisted pair. The proposed pulse generator uses a hard switching configuration such that the pulse generator can vary the pulse width from 150 ns to DC and increase the switching pulse cycle beyond 1 MHz by changing the control signals of the SiC MOSFETs.

Acute circumflex coronary artery occlusion; dilemma in diagnosis and management

Background

Acute coronary syndrome (ACS) with occlusion of the circumflex coronary artery (LCX) poses diagnostic dilemma that may lead to a delay in reperfusion.

Purpose

We sought to assess the diagnostic significance of initial electrocardiography (ECG) changes in patients with acute LCX occlusion in relation to its clinical characteristics and the management.

Methods

From consecutive 1269 patients with ACS who were admitted to our institution during a 5-year period (2015–2019), 138 patients with ACS due to LCX occlusion were analyzed for clinical, ECG and angiographic presentation, and the door-to-balloon (DTB) time. ECG changes were classified into 4 different patterns: 1) ST-elevation in inferior/lateral leads (ST-E); 2) ST-depression in V1-V4 (ST-D); 3) no significant ST changes (No-ST); and 4) others.

Results

(1) No-ST pattern was found in 47 patients (34%), ST-E in 47 patients (34%), ST-D in 25 patients (18%) and others in 19 patients (14%). (2) Occlusion site: Proximal LCX; 16 patients with No-ST (34%), 6 patients with ST-E (13%), 13 patients with ST-D (52%). Distal LCX; 28 patients with No-ST (60%), 35 patients with ST-E (74%), 11 patients with ST-D (44%) (p=0.007). (Table) (3) Echocardiographic identification of left ventricular asynergy; 31 patients with No-ST (66%), 38 patients with ST-E (81%), 22 patients with ST-D (88%). (4) No-ST group was associated with longer DTB time; 245 min (170–562 min), compared to 93 min (83–121 min) in ST-E group and 97 min (70–129 min) in ST-D group (p<0.0001). DTB time ≤90 min was significantly uncommon in No-ST group (11%), compared to ST-E group (46%) and ST-D group (43%) (p=0.0004). (Figure)

Conclusion

One-third of the patients with LCX-ACS showed no ST changes, resulting in significantly longer DTB time. Improving diagnostic accuracy with anticipation for LCX-ACS and the use of echocardiographic examination and also the possible application of posterior leads (V7-V9) recording is challenging but critical to avoid delayed reperfusion and to improve outcomes in these patients without ECG changes.

Funding Acknowledgement

Type of funding sources: None.

Impact of transcatheter aortic valve implantation on coronary flow reserve by transthoracic Doppler echocardiography 1-year after the intervention in severe aortic stenosis patients

Background

Coronary flow reserve (CFR) which is one of indexes reflecting coronary microcirculation in patients without significant epicardial coronary lesions can be impaired in patients with severe aortic stenosis (AS). It has been shown that CFR is an independent predictor for future cardiovascular events in AS patients. Transcatheter aortic valve implantation (TAVI) has rapidly become widespread and is becoming the standard treatment for severe AS. This procedure may have a good effect on CFR due to reduction of severe afterload in patients with severe AS. Although the recent reports evaluated change in CFR immediately and 6 months after TAVI, it has not been evaluated whether impaired CFR improves 1-year after TAVI in AS patients with preserved left ventricular ejection fraction (LVEF).

Purpose

The purpose of the present study was to investigate whether impaired CFR improves 1-year after TAVI in severe AS patients with preserved LVEF.

Methods

The study population consists of consecutive 105 patients with severe AS undergoing TAVI. Exclusion criteria were atrial fibrillation, old myocardial infarction, history of coronary artery bypass grafting, significant lesions in the left anterior descending artery (LAD), moderate or severe mitral valve disease, history of valve replacement, LVEF <50% and preoperative CFR >2.2. CFR was obtained from coronary flow velocity by transthoracic echocardiography at rest and maximal hyperemia in LAD before, immediately and 1-year after TAVI. We compared CFR between before and after TAVI in the study patients who did not meet the exclusion criteria.

Results

After exclusion of 76 patients who met the exclusion criteria, the final study patients consist of 29 patients (8 male, 84.9±5.2 years). There was no significant difference in LVEF (61.3±3.4% vs 61.6±4.4%, P=0.667) and LV end-diastolic volume (LVEDVI; 58.2±9.2 mL/m2 vs 55.8±9.0 mL/m2, P=0.089) between before and immediately after TAVI. LVEF (61.0±2.8%, P=0.721) and LVEDVI (58.0±9.1 mL/m2, P=0.949) 1-year after TAVI were similar to those before TAVI. There was no significant difference in coronary flow velocity at rest between before and immediately after TAVI (27.4±8.9 vs 24.4±7.0 cm/s, P=0.051) and between before and 1-year after TAVI (25.9±8.3 cm/s, P=0.396). Coronary flow velocity at maximal hyperemia 1-year after TAVI significantly increased compared with that before TAVI (from 48.8±13.9 to 67.9±21.0 cm/s, P<0.001) while there was no significant difference between before and immediately after TAVI (52.0±12.0 cm/s, P=0.186). Impaired CFR before TAVI (1.82±0.28) increased immediately (2.03±0.39, P=0.009) and 1-year after TAVI (2.69±0.57, P<0.001).

Conclusions

The present results suggest that impaired CFR in patients with preserved LVEF improves 1-year after TAVI. TAVI may have a good effect on CFR in severe AS patients with preserved LVEF.

Funding Acknowledgement

Type of funding sources: None.

Clinical impact of CREDO-kyoto risk score on in-hospital bleeding in patients with acute coronary syndrome

Background/Introduction

CREDO-Kyoto bleeding risk score was developed to predict the post-discharge bleeding events in patients with percutaneous coronary intervention. However, there were limited reports of the effectiveness of this score to predict the in-hospital bleeding events in patients with acute coronary syndrome (ACS).

Methods

We evaluated 562 consecutive ACS patients in Saga university hospital between 2014 and 2019. Primary outcome was major bleeding during hospitalization. Major bleeding was defined as the GUSTO moderate/severe bleeding. Patients were classified into three groups according to the CREDO-Kyoto bleeding risk score (low, intermediate and high).

Results

Major bleeding events occurred in 12.1% of all patients during hospitalization. Patients in the high risk group (n=22) had significantly higher incidence of major bleeding than those in the intermediate (n=113) and the low risk groups (n=427) (22.7%, 18.6%, versus 9.8%, respectively, p=0.018, see figure). Multivariate analysis showed that intermediate and high risk groups were independent predictors for the in-hospital major bleeding.

Conclusions

CREDO-Kyoto risk score successfully identified high risk ACS patients for the major bleeding during hospitalization.

Funding Acknowledgement

Type of funding sources: None. Results

Absence of microsatellite instability in extramammary Paget's disease

Background

Deficiency of DNA mismatch repair (MMR) induces microsatellite instability (MSI). Pembrolizumab, an antibody targeting PD‐1 (an immune checkpoint inhibitor), is more effective against MMR‐deficient tumours than against MMR‐proficient tumours. The status of MMR is a useful biomarker for predicting the effectiveness of pembrolizumab administration. Although the status of MMR has attracted attention in skin tumours, there are few reports on MSI in extramammary Paget's disease (EMPD).

Objectives

To evaluate the status of MMR in patients with EMPD.

Materials & Methods

One hundred one patients with EMPD were included. MMR status of the genomic DNA of each subject was analysed using Promega panel (approved as a companion diagnostic agent for the administration of pembrolizumab).

Results

MSI testing showed the occurrence rates of MSI‐high (more than two markers are unstable), MSI‐low (one marker is unstable) and MSS (all markers are stable) tumour tissues were 0% (0/101), 1.0% (1/101) and 99.0% (100/101), respectively.

Conclusion

The status of MMR may not be useful for the potential therapeutic application of pembrolizumab.

Changes in beta and high-gamma power in resting-state electrocorticogram induced by repetitive transcranial magnetic stimulation of primary motor cortex in unanesthetized macaque monkeys

Repetitive transcranial magnetic stimulation (rTMS) is now widely used as a means of neuromodulation, but the details of the mechanisms by which rTMS works remain unclarified. As a step forward to unveiling the neural phenomena occurring underneath the TMS coil, we conducted an electrophysiological study using awake and unanesthetized monkeys with subdural electrocorticogram (ECoG) electrodes implanted over the primary motor cortex (MI). We evaluated the effects of low-frequency (1 Hz) and high-frequency (10 Hz) rTMS on the resting-state ECoG signals in the stimulated MI, as well as the motor evoked potentials (MEPs) in the contralateral hand. Following the 1-Hz rTMS application, the ECoG beta band power and the MEP amplitude were significantly decreased. Following the 10-Hz rTMS application, the ECoG high-gamma power and the MEP amplitude significantly increased. Given that beta and high-gamma activities in the ECoG reflect the synchronous firing and the firing frequency of cell assemblies, respectively, in local neural circuits, these results suggest that low-frequency rTMS inhibits neural activity by desynchronizing the firing activity of local circuits, whereas high-frequency rTMS facilitates neural activity by increasing the firing rate of cell assemblies in the local circuits.

Stroke, systemic embolism and bleeding rate in non-valvular atrial fibrillation patients without anticoagulation on the real world data in Japan

Background

Anticoagulant therapy is recommended in patients with non-valvular atrial fibrillation (NVAF) for those with CHADS2 ≥2. However, there have been significant number of subjects with CHADS2 ≥2 who receive no anticoagulation. Most of reported real world data have been collected mainly before wide spread use of DOAC. This study evaluated the clinical outcome of no anticoagulant drug therapy in NVAF.

Methods

This study is a non-interventional, observational, retrospective cohort study of NVAF patients in Mie-LIP Database, which is a regional clinical database joining 1 university hospital and 8 general hospitals in Mie prefecture in Japan. Patient enrolment was conducted from 1st Jan. 2016 to 31st Dec. 2018. The primary outcome events are ischemic stroke, systemic embolism, and bleeding events (bleeding to need a blood transfusion, intracranial bleeding, intraocular bleeding, and gastrointestinal bleeding).

Results

7001 patients were included in the current analysis, 2550 patients, 36.4% were treated without any anticoagulant drug therapy. Table 1 shows patients with no anticoagulant drug therapy, mean age was 75.4 years and 42.2% of patients were female. The most frequent comorbidities included hypertension (50.0%), diabetes mellitus (28.2%), heart failure (14.0%), ischemic stroke (12.7%), vascular disease (14.4%) respectively. The annual incidence of ischemic stroke, systemic embolism per 100 person-years is 3.7, and that in each CHADS2 group is 0: 1.4, 1: 1.4, 2: 3.2, 3–6: 8, respectively in Figure 1. The annual incidence of bleeding events is 1.5, and that in each CHADS2 group is 0: 0.7, 1: 1.0, 2: 1.2, 3–6: 2.9, respectively.

Conclusions

Approximately one-thirds of subjects have not received any anticoagulation in the modern DOAC in daily clinical practice in Japan. The rate of ischemic stroke and systemic embolism increased by CHADS2. Stroke or SEE rate was very low in subjects with CHADS2 ≤1, supporting no indication of anticoagulation in current guidelines. Regarding subjects with CHADS2>2, considering the higher risk of stroke, use of anticoagulant drug therapy is recommended.

Funding Acknowledgement

Type of funding source: None

Relative contributions of large-scale and wedgelet currents in the substorm current wedge

We examined how much large-scale and localized upward and downward currents contribute to the substorm current wedge (SCW), and how they evolve over time, using the THEMIS all-sky imagers (ASIs) and ground magnetometers. One type of events is dominated by a single large-scale wedge, with upward currents over the surge and broad downward currents poleward-eastward of the surge. The other type of events is a composite of large-scale wedge and wedgelets associated with streamers, with each wedgelet having comparable intensity to the large-scale wedge currents. Among 17 auroral substorms with wide ASI coverage, the composite current type is more frequent than the single large-scale wedge type. The dawn-dusk size of each wedgelet is ~ 600 km in the ionosphere (~ 3.2 R _E in the magnetotail, comparable to the flow channel size). We suggest that substorms have more than one type of SCW, and the composite current type is more frequent.

A case of resected retroperitoneal metachronous solitary metastasis from caecal cancer

Colorectal cancer metastasis to the retroperitoneum, especially solitary metastasis allowing curative resection, is rare. We report a case of complete resection of retroperitoneal metachronous solitary metastasis from caecal cancer without distant metastasis. An 80-year-old woman with caecal cancer underwent laparoscopic ileocaecal resection with regional lymph node dissection. According to the eighth edition of the TNM classification, the pathological diagnosis was stage IIA (T3N0M0). Six months following the surgery, computed tomography revealed a solitary mass of 2cm diameter, dorsal to the right kidney. A second procedure for the removal of the tumour was performed. The lesion was pathologically diagnosed as a metachronous solitary retroperitoneal metastasis from caecal cancer. The patient is surviving and free from recurrence 17 months following the second procedure.

0561 Differences in Nasopharyngoscopic Airway Form Between Awake and Sleep, Sitting and Recumbent Position and Techniques

Introduction

To examine and compare the information derived from flexible fiber-optic nasopharyngoscopy in awake mimic snoring (AMS), Müller’s Maneuver (MM) and drug-induced sleep endoscopy (DISE), to determine if AMS and MM can be used in substitution for DISE as a streamlined method. We investigated their relation with the level and pattern of obstruction detected on AMS, MM and DISE.

Methods

This is a retrospective study of 15 obstructive sleep apnea patients with apnea hypopnea index from 8.3 to 105.2, ages 20 to 80 were included. Each patient underwent polysomnography and thorough a physical examination, including flexible nasopharyngoscopy with AMS, MM and DISE. Airway obstruction on these endoscopic procedures were described according to airway level and pattern of obstruction. They were classified 5 different types; Uvula type: anterior-posterior vibration of the uvula, no airway obstruction; L-R velum type: lateral (the left and right directions) airway narrowing at velum level, no airway obstruction; A-P velum type: anterior-posterior total airway obstruction at velum level; Tonsillar type: total airway obstruction at pharyngeal level; Circumferential type: circumferential total airway obstruction at velum level. AMS and MM were performed with patients in sitting and in recumbent position. DISE was performed only in recumbent position.

Results

In review of the three procedures, the results were much different. Airway was obstructed in all cases(100%, 15 of 15)in DISE, but not all cases in AMS and MM. When tonsillar type was seen in AMS, it was also seen in MM and DISE(100%, 5 of 5).

Conclusion

Flexible fiber-optic nasopharyngoscopy appears to be useful for evaluating airway obstruction. It might be not suitable to use AMS and MM in substitution for DISE(except tonsillar type). Muscle tonic relaxation of the upper airway between AMS, MM and DISE might be different (DISE>MM>AMS, recumbent>sitting).

Support

 

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Cerebellar outputs contribute to spontaneous and movement-related activity in the motor cortex of monkeys

Cerebellar outputs originate from the dentate nucleus (DN), project to the primary motor cortex (M1) via the motor thalamus, control M1 activity, and play an essential role in coordinated movements. However, it is unclear when and how the cerebellar outputs contribute to M1 activity. To address this question, we examined the response of M1 neurons to electrical stimulation of the DN and M1 activity during performance of arm-reaching tasks. Based on response patterns to DN stimulation, M1 neurons were classified into facilitation-, suppression-, and no-response-types. During tasks, not only facilitation- and suppression-type M1 neurons, but also no response-type M1 neurons increased or decreased their firing rates in relation to arm reaching movements. However, the firing rates of facilitation- and suppression-type neurons were higher than those of no-response-type neurons during both inter-trial intervals and arm reaching movements. These results imply that cerebellar outputs contribute to both spontaneous and movement-related activity in the M1, which help to maintain muscle tones and execute coordinated movements, although other inputs also contribute to movement-related activity. Pharmacological inactivation of the DN supports this notion, in that DN inactivation reduced both spontaneous firing rates and movement-related activity in the M1.