Improved Blood Suppression of Motion-Sensitized Driven Equilibrium in High-Resolution Whole-Brain Vessel Wall Imaging: Comparison of Contrast-Enhanced 3D T1-Weighted FSE with Motion-Sensitized Driven Equilibrium and Delay Alternating with Nutation for Tailored Excitation

BACKGROUND AND PURPOSE

High-resolution vessel wall MR imaging is prone to slow-flow artifacts, particularly when gadolinium shortens the T1 relaxation time of blood. This study aimed to determine the optimal preparation pulses for contrast-enhanced high-resolution vessel wall MR imaging.

MATERIALS AND METHODS

Fifty patients who underwent both motion-sensitized driven equilibrium and delay alternating with nutation for tailored excitation (DANTE) preparation pulses with contrast-enhanced 3D-T1-FSE were retrospectively included. Qualitative analysis was performed using a 4-grade visual scoring system for black-blood performance in the small-sized intracranial vessels, overall image quality, severity of artifacts, and the degree of blood suppression in all cortical veins as well as transverse sinuses. Quantitative analysis of the M1 segment of the MCA was also performed.

RESULTS

The qualitative analysis revealed that motion-sensitized driven equilibrium demonstrated a significantly higher black-blood score than DANTE in contrast-enhanced 3D-T1-FSE of the A3 segment (3.90 versus 3.58, P < .001); M3 (3.72 versus 3.26, P = .004); P2 to P3 (3.86 versus 3.64, P = .017); the internal cerebral vein (3.72 versus 2.32, P < .001); and overall cortical veins (3.30 versus 2.74, P < .001); and transverse sinuses (2.82 versus 2.38, P < .001). SNR_lumen, contrast-to noise ratio_wall-lumen, and SNR_wall in the M1 vessel were not significantly different between the 2 preparation pulses (all, P > .05).

CONCLUSIONS

Motion-sensitized driven equilibrium demonstrated improved blood suppression on contrast-enhanced 3D-T1-FSE in the small intracranial arteries and veins compared with DANTE. Motion-sensitized driven equilibrium is a useful preparation pulse for high-resolution vessel wall MR imaging to decrease venous contamination and suppress slow-flow artifacts when using contrast enhancement.

Urine osmolality predicts worsening renal function and poor prognosis in acute decompensated heart failure

Background/Purpose

Worsening renal function (WRF) can sometimes occur in the patients with acute decompensated heart failure (ADHF) and increase the risk of morbidity and mortality (1). In a previous study, it was reported that fractional excretion of sodium (FENa) reflects net sodium reabsorption from nephron segments and predicts WRF during treating ADHF (2). On the other hand, recently the new drugs which approach urine concentration mechanism and affect urine osmolality (U-OSM), such as tolvaptan and sodium-glucose cotransporter-2 inhibitor, have begun to be widely used as treatment of heart failure. Thus, we focused on U-OSM, which reflects not only sodium handling but also water excretion controlled by the collecting duct, and evaluated the association between WRF and U-OSM. Moreover, previous studies have demonstrated that FENa, fractional excretion of urea nitrogen and transtubular potassium concentration gradient are markers for long-term prognosis in patients with ADHF (3–5). Therefore, we also studied whether U-OSM can predict prognosis in ADHF.

Methods

A total of 157 patients admitted to our hospital because of a primary diagnosis of ADHF from February 2020 through July 2021 were retrospectively reviewed. U-OSM in the spot urinary samples were examined within 72 hours after admission. U-OSM was calculated based on the following validated formula (6): U-OSM = 1.07 × {2 × [urine sodium (mEq/L)] + [urine urea nitrogen (mg/dL)]/2.8 + [urine creatinine (mg/dl)] × 2/3} + 16.2. The primary outcome was the occurrence of WRF during hospitalization. WRF was defined as increased serum creatinine ≥0.3 mg/dL from baseline (7). The secondary outcome was the occurrence of ADHF readmission and all-cause death within 180 days after discharge.

Results

Primary Outcome. WRF developed in 46% of all patients. In the patients that developed WRF during hospitalization, U-OSM was significantly lower than in the patients without WRF (366±106 mOsm/L versus 430±128 mOsm/L; P&lt;0.001). Receiver operating characteristic curve analysis revealed the optimal cutoff values of U-OSM was 403 mOsm/L (AUC 0.64; 95% CI: 0.56–0.72; P&lt;0.001) to predict the WRF (Figure 1). On multivariable logistic regression analysis, U-OSM (OR, 1.99, 95% CI: 1.27–3.12; p=0.003) and serum creatinine (OR, 1.00, 95% CI: 0.99–1.00; P=0.009) were independent predictors of WRF.

Secondary Outcome. There were 34 patients (22%) readmitted and 9 patients (6%) died within 180 days after discharge. ROC curve analysis revealed the optimal cutoff values of U-OSM as 349 mOsm/L (C-statistic 0.74; 95% CI: 0.65–0.83; P&lt;0.001) to predict ADHF readmission and all-cause death within 180 days (Figure 2A). On Kaplan-Meier analysis, the secondary outcome was significantly higher in patients with U-OSM&lt;349 mOsm/L (u-OSM≥349, 57%, U-OSM&lt;349, 43%; HR, 0.99; 95% CI: 0.99–1.00, P&lt;0.001) (Figure 2B).

Conclusion

U-OSM on admission may be a predictor of WRF and a prognostic marker in ADHF patients.

Funding Acknowledgement

Type of funding sources: None.

Usefulness of the synthesized 18-lead ECG in identify the origin of premature ventricular contractions

Background

There are have been reports on the 12-lead ECG waveforms used to identify ventricular premature contractions (VPCs), but there are not enough algorithms. On the other hand, the synthesized 18-lead ECG adds the right-side chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9) to the 12-lead ECG.

Purpose

This aim of this study was to evaluate whether the waveforms of the 18-lead ECG are useful in predicting the origin of VPCs.

Methods

We studied 86 consecutive patients (age :61.8±16.0 years, male: 54.5%) enrolled from multicenter who underwent radiofrequency catheter ablation for VPCs. We retrospectively investigated the association between origin of the VPCs and characteristics of the synthetic 18-leads ECG.

Results

The 18-lead ECG showed a specific pattern for the VPC originating near the His-bundle. In 17 cases, the QRS morphology in V5R exhibited a QS pattern, and 13 of 17 cases had VPCs originating near the His-bundle. In the other 69 cases, V5R did not exhibit a QS pattern. ROC curve analysis showed that the QS pattern in V5R predicted VPC originating near the His-bundle with high accuracy: sensitivity 100.0%, specificity 94.5%, and AUC 0.98. Furthermore, the positive predictive value was 76.5% and negative predictive value 100.0%.

Conclusion

The QS pattern shown in V5R of the 18-lead ECG was a useful parameter for identifying VPCs originating near the His-bundle, which might be a good reference indicator during radiofrequency catheter ablation for VPCs.

Funding Acknowledgement

Type of funding sources: None.

Impact of heart rate reduction on recurrence after catheter ablation of persistent atrial fibrillation

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Johnson & Johnson KK

OnBehalf

OCVC Arrhythmia Investigators

Background

Predicting heart rate (HR) after restoration of sinus rhythm (SR) remains one of the challenges when performing catheter ablation (CA) of persistent atrial fibrillation (AF).

Purpose

To evaluate the association between pre-ablation HR during AF and post-ablation HR during SR, and whether the HR reduction is associated with AF recurrence.

Methods

The analysis was performed from the EARNEST-PVI trial, a randomized controlled trial designed to assess a CA strategy for persistent AF, which was conducted in the Osaka region of Japan. After excluding patients with beta-blocker prescription, a total of 216 patients (median age, 67 years; 20% female; 23% long-standing persistent AF) with AF rhythm at baseline and SR at discharge were enrolled in this study. Baseline HR during AF and post-ablation HR during SR was measured on admission and at discharge using the 12-lead electrocardiograms, respectively.

Results

There was a mild correlation between baseline HR (median 82 [interquartile range 72-95] bpm) and post-ablation HR (78 [48-117] bpm) (r = 0.27, p &lt;0.001). Reduction in HR was positively associated with baseline HR (r = 0.79, p &lt;0.001) and was negatively associated with post-ablation HR (r = - 0.37, p &lt;0.001). During the follow-up of 1 year, 56 patients (25.9%) experienced AF recurrence. HR reduction had the higher diagnostic accuracy in predicting AF recurrence than HR at baseline and HR after CA (area under the curve, 0.625; 95% confidence interval, 0.557–0.690; p = 0.003). AF recurrence rate was significantly higher in 141 patients with smaller HR reduction (cut-off, &lt;14bpm) than those with larger HR reduction (31.9% vs. 14.7%, p = 0.009). After adjustment of age, gender, long-standing persistent AF, and CA strategy, HR reduction of &lt;14 bpm was a significant predictor of AF recurrence (hazard ratio, 2.32; 95% confidence interval, 1.20–4.51; p = 0.013).

Conclusions

There was a mild correlation between HR during AF and HR after restoration of SR in patients underwent CA of persistent AF. HR reduction after restoration of SR predicted AF recurrence.

Reappraising the role of baseline plasma C-reactive protein levels on recurrence after catheter ablation of persistent atrial fibrillation: insight from EARNEST-PVI trial

Background

Subclinical inflammation is an important pathogenesis of developing and sustaining atrial fibrillation (AF). Because AF itself contribute to the inflammatory response, the role of baseline subclinical inflammation on AF recurrence after catheter ablation (CA) remains controversial in patients with persistent AF.

Purpose

To evaluate whether baseline plasma C-reactive protein (CRP) levels, a sensitive marker of inflammation, are associated with AF recurrence following CA.

Methods

The analysis was performed from the EARNEST-PVI trial, a randomized controlled trial designed to assess a CA strategy for persistent AF, which was conducted in the Osaka region of Japan. A total of 441 patients (median age, 67 years; 26% female; 25% long-standing persistent AF) whose plasma CRP levels were measured at baseline were included in this study.

Results

At baseline, a median (interquartile range) of plasma CRP level was 0.10 [0.06–0.19] mg/dl. Plasma CRP levels significantly increased at discharge (0.83 [0.21–1.84] mg/dl, p&lt;0.001) and decreased 1 year after CA (0.10 [0.05–0.20] mg/dl, p=0.040) compared to the baseline value. During the follow-up of 1 year, 115 patients (26%) experienced AF recurrence, and the incidence was significantly higher in 124 patients with low CRP levels at baseline (cut-off ≤0.06 mg/dl) than the other 317 patients (33.9% vs. 23.0%, p=0.017). After adjustment of age, gender, body mass index, long-standing persistent AF, CA strategy, and plasma brain natriuretic peptide levels, low plasma CRP levels was a significant predictor of AF recurrence (hazard ratio, 1.51; 95% confidence interval, 1.02–2.24; p=0.042).

Conclusions

Low plasma CRP levels at baseline predicted AF recurrence in the EARNEST-PVI trial. Reappraising the role of CRP on AF recurrence may be needed in patients with persistent AF.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Johnson & Johnson KK

Renal function and arrhythmia outcomes in persistent atrial fibrillation patients after catheter ablation: subanalysis of the EARNEST-PVI trial

Background

Atrial fibrillation (AF) reduces the renal function. Renal dysfunction and AF often coexist. Catheter ablation (CA) of persistent AF can maintain a sinus rhythm and may improve the renal function.

Purpose

We sought to elucidate whether the estimated glomerular filtration rate (eGFR) in patients with persistent AF was increased after CA, especially with the presence of an AF recurrence.

Methods

We enrolled 487 persistent AF patients whose eGFR data were available both before and 1-year after the CA out of 512 patients in the EARNEST-PVI trial.

Results

The mean age was 65±9 year and 113 patients (24.8%) had long-standing persistent AF. We compared the eGFR at baseline with that 1-year after the CA. AF recurrences were recognized in 118 patients (25.8%). The eGFR was similar between the group without recurrence and that with recurrence at baseline (without AF recurrence vs. with AF recurrence; 63.8±14.3 vs. 62.7±13.6 mL/min/1.73m2, p=0.46). In patients without AF recurrence, the G1, G2, G3a, G3b, G4, and G5 were 13 (3.8%), 198 (58.4%), 98 (28.9%), 26 (7.7%), 3 (0.9%), and 1 (0.3%), respectively at baseline. In the patients with AF recurrence, the G1, G2, G3a, G3b, G4, and G5 were 3 (2.5%), 68 (57.8%), 38 (32.2%), 6 (5.1%), 3 (2.5%), and 0 (0%), respectively at baseline. The ΔeGFR was significantly higher in the patients without AF recurrence than in those with AF recurrence (without AF recurrence vs. with AF recurrence; 5.1 [−0.3, 10.8] vs. 3.0 [−3.0, 7.6], p=0.0033). In the patients without AF recurrence, a better eGFR class at 1-year after the CA than in those before the CA was recognized in 75 patients (22.1%), while it was recognized in 19 patients (16.1%) with AF recurrences.

Conclusion

Successful catheter ablation in patients with persistent AF led to a better renal outcome.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): This study was funded by Medtronic, Johnson & Johnson, and Abbott.

Differences in quality of life improvement with pulmonary vein isolation alone vs. more extensive ablation of persistent atrial fibrillation: insights from the EARNEST-PVI trial

Background

Improving the quality of life (QoL) is one of the main purposes of catheter ablation (CA) of persistent atrial fibrillation (AF). QoL improvement in persistent AF patients has not been fully clarified. The EARNEST-PVI trial was a multi-center randomized trial comparing clinical outcomes of pulmonary vein isolation (PVI) alone and more intensive ablation in addition to PVI including complex fractionated atrial electrogram (CFAE) and linear ablation (PVI plus).

Purpose

To investigate the QoL change after persistent AF ablation and the differences between the PVI-alone strategy and the PVI plus strategy.

Methods

In the EARNEST-PVI trial, patients with persistent AF who underwent an initial catheter ablation (n=512) were randomly assigned in a 1:1 ratio to either PVI alone or PVI plus. Quality of life was assessed at baseline and at 12 months after ablation for AF using the 36-Item Short Form Health Survey. Scores were also converted to a physical health component summary (PCS), a mental health component summary (MCS) and a role/social component summary (RCS).

Results

In the EARNEST-PVI trial, the PVI alone strategy was associated with higher recurrence rate compared with the PVI plus additional ablation strategy. After excluding 68 patients for whom preoperative or postoperative QoL assessment was not available, 222 patients were evaluated respectively. Overall, significant improvements in PCS (46.2±11.4 to 48.7±11.4]), MCS (50.1±8.8 to 54.3±8.6) and RCS (44.6±13.3 to 48.6±11.3) occurred 12 months after ablation (P&lt;0.001, respectively). Although significant QoL improvement occurred in both PVI alone and PLI plus strategies, the changes in PCS was greater in the PVI-plus than that in PVI-alone (3.5±10.3 vs 1.5±10.6, P=0.04).

Conclusions

Ablation for persistent atrial fibrillation improved both physical and mental quality of life. The PVI-plus strategy showed greater improvement in physical QoL.

Funding Acknowledgement

Type of funding sources: None. QoL improvement

A novel nairovirus associated with acute febrile illness in Hokkaido, Japan

The increasing burden of tick-borne orthonairovirus infections, such as Crimean-Congo hemorrhagic fever, is becoming a global concern for public health. In the present study, we identify a novel orthonairovirus, designated Yezo virus (YEZV), from two patients showing acute febrile illness with thrombocytopenia and leukopenia after tick bite in Hokkaido, Japan, in 2019 and 2020, respectively. YEZV is phylogenetically grouped with Sulina virus detected in Ixodes ricinus ticks in Romania. YEZV infection has been confirmed in seven patients from 2014–2020, four of whom were co-infected with Borrelia spp. Antibodies to YEZV are found in wild deer and raccoons, and YEZV RNAs have been detected in ticks from Hokkaido. In this work, we demonstrate that YEZV is highly likely to be the causative pathogen of febrile illness, representing the first report of an endemic infection associated with an orthonairovirus potentially transmitted by ticks in Japan.

Here, Kodama et al. describe the discovery, isolation and characterization of a novel tick-borne orthonairovirus, designated Yezo virus (YEZV), from patients with an acute febrile illness in Japan. Serological testing of wildlife and molecular screening of ticks suggest an endemic circulation of YEZV in Japan.

A self-reported measurement scale on a potential component of competency in the healthcare staff engaged in the prevention and control of non-communicable disease in Fiji

Background

According to the World Health Organization, an estimated 80% or more deaths in Pacific island countries, including Fiji, were related to non-communicable diseases (NCDs). Although competency-based approaches have been effective for developing healthcare workers’ capabilities, there are only a few reports on competency scales of healthcare workers for NCD prevention. We aimed to develop a self-reported measurement scale on a potential component of competency in the healthcare staff engaged in the prevention and control of NCDs in Fiji.

Methods

There were 378 Ministry of Health and Medical Services staff members working on NCD prevention and control in Fiji included in this study, which was a cross-sectional survey of social factors, working situation factors, and competency. Exploratory factor analysis was conducted to assess potential competency components, whereas Cronbach’s α coefficient and analysis of variance were used to assess the validity and reliability of the scale items, respectively. Multivariate regression analyses were conducted to analyze the respondents’ factor scores relative to social status and work situations.

Results

The factor analysis revealed 16 items that identified competency in four work types: 1) work management, 2) monitoring and evaluation, 3) community partnership, and 4) community diagnosis. The monitoring and evaluation roles were related to ethnic background, community partnership was related to religion, and community diagnosis was related to academic qualifications.

Conclusions

Based on the results, we developed a competency scale for the four work types. This scale can help healthcare workers engage in better management of residents with NCDs in Fiji.

1181Role of rho-mdia1 signaling to maintain cardiac function in response to pressure overload in mice

Background

Cardiac hypertrophy is a compensatory response to pressure overload that leads to heart failure. Recent studies have shown that Rho signaling has crucial regulatory roles in actin cytoskeleton rearrangement during cardiac hypertrophic responses. Rho is rapidly activated in response to pressure overload, but the mechanisms by which Rho and its downstream proteins control actin dynamics during hypertrophic responses remain unclear.

Objective

To identify the essential roles of mDia1 (Rho-effector molecule) in pressure overload-induced ventricular hypertrophy.

Methods and results

Male wild-type (WT) and mDia1-knockout (mDia1KO) mice (10–12 weeks old) were subjected to transverse aortic constriction (TAC) or a sham operation. The heart weight/tibia length ratio, cardiomyocyte cross-sectional area, left ventricular wall thickness, and expression of hypertrophy-specific genes were significantly decreased in mDia1KO mice 3 weeks after TAC, and the mortality rate was higher at 12 weeks. Echocardiography and the pressure-volume loop indicated that mDia1 deletion increased the severity of heart failure 8 weeks after TAC. Microarray gene expression profiling showed that the induction of immediate early genes due to the TAC operation was significantly lower in mDia1KO mice than WT mice, as was the activation of extracellular signal-regulated kinase (ERK) and focal adhesion kinase (FAK). We examined the role of mDia1 in neonatal rat ventricular cardiomyocytes (NRVMs) exposed to mechanical stress. The siRNA-mediated silencing of mDia1 attenuated stretch-induced ERK and FAK phosphorylation, and gene expression of c-fos. Importantly, loss of mDia1 suppressed an increase in the F/G-actin ratio in response to pressure overload in the mice. In addition, increases in nuclear myocardin-related transcription factors (MRTFs) and serum response factor (SRF) were perturbed in response to pressure overload in mDia1KO mice and to mechanical stretch in mDia1 depleted NRVMs.

Conclusions

Rho-mDia1, through actin dynamics, plays critical roles in pressure overload-induced hypertrophy by regulating ERK and FAK phosphorylation and the transcriptional activity of MRTF-SRF.

4090Maximum standardized uptake value of pericardial fat for prediction of ventricular arrhythmias in patients with cardiac sarcoidosis

Background

Cardiac sarcoidosis is a cause of epicarditis and sustained life-threatening ventricular arrhythmias. These arrhythmias occasionally arise from epicardial. Positron emission tomogramphy-comututed tomography (PET-CT) is useful for diagnosis with sarcoidosis. However, the usefulness for prediction of ventricular arrhythmias in patients with cardiac sarcoidosis is unknown.

Objective

We hypothesized that the evaluation of pericardial fat inflammation could identify high-risk sarcoidosis patients for ventricular arrhythmias.

Methods

We enrolled 20 consecutive patients with cardiac sarcoidosis performed PET-CT between August 2016 and December 2018. In each case, we measured the maximum standardized uptake value (SUVmax) of pericardial fat around the left atrium, both ventricules, atrioventricular groove, and left main coronary.

Results

Seven patients experienced ventricular tachycardia (VT) or ventricular fibrillation (VF). VT/VF patients had significantly more complete right bundle branch block (P=0.035), larger left atrial dimension (P=0.021), larger left ventricular end-diastolic dimension (P=0.005), lower ejection fraction (P=0.007), and higher E/e' (P=0.004). SUVmax of pericardial fat in the roof of left atrium (LA) and left ventricular (LV) with VT/VF patients were significantly higher than non-VT/VF patients (LA: 1.63 vs 1.32, P=0.0311; LV: 1.84 vs 1.26, P=0.045). The cut-off values of SUVmax derived from the ROC curve in the roof of LA and LV are 1.47 and 1.59 respectively. The Kaplan Meire estimator showed that high SUVmax patients in the roof of LA had significantly more detection of NSVT.

Conclusions

Our results suggest the relationship between SUVmax and VT/VF occurrence in patients with cardiac sarcoidosis. The evaluateon of SUVmax may be useful for VT/VF risk stratification.

P1628Angiopoietin-like protein (Angptl) 2 secreted from epicardial adipose tissue induces atrial myocardial fibrosis

Background

Using excised human left atrial appendage samples, we previously demonstrated that epicardial adipose tissue (EAT) are highly associated with atrial myocardial fibrosis as a substrate of atrial fibrillation (AF). We also reported the relationship between Angptl2 in EAT and atrial fibrosis. However, the mechanism is not clear. The purpose is to clarify the mechanisms underlying the effect of EAT on the atrial myocardium.

Methods

Human peri-left atrial EAT and abdominal subcutaneous adipose tissue (SAT) samples were obtained from 6 cases (2 females, 70.2±13.2 years). 50 mg of EAT and SAT were quickly washed with PBS and centrifuged 1min at 1200rpm. After 3 times this procedures, adipose tissues were cultured in DMEM F12 medium with Fetal bovine Serum (FBS) overnight.

After pre-incubation, EAT and SAT tissues were washed and centrifuge d three times and cultured in medium without FBS for 24hours. Finally, we collected oozed medium (conditioned medium) and used for experiments.

Concentrations of Angptl2 in conditioned medium were measured by ELISA.

To study the effects of conditioned medium, we used “organo-culture” system. Isolated atrium from 8week old male Sprague-Dawley rats were placed on the porous membrane with the endothelial face toward the membrane. After that, loading medium (conditioned medium:culture medium = 1:4), culture medium (control), or recombinant Angptl2 were dropped onto the epicardial face of the atrium once a day and incubated for 7 days (37°C, 5% CO2).

Then, histological and immunohistochemical analysis were performed. We also performed quantitative reverse transcription–polymerase chain reaction (RT–PCR) analysis.

Next, we isolated and cultured neonatal rat fibroblast and loaded Angptl2 for 24 hours.After collected these cells, we performed western blotting analysis.

Results

Atria organo-culture incubated for 7 days with conditioned medium showed global fibrosis. At epicardial side, fibrotic area of EAT group was significantly greater compared to that of SAT and control group (P<0.05).

mRNA of Col1a1, col3a1 and TGFβ1 were significantly increased in EAT group compared with the SAT and control group.

And, the concentration of conditioned medium created from EAT was significant higher than that from SAT (P<0.05).

Then, we dropped 500 ng/ml of recombinant Angptl2 onto the rat atria. Fibrotic area of Angptl22 group significantly greater than that of control with increasing number of α-SMA positive cells, and mRNA of col3a1 and TGFβ1 were significantly increased in Angptl2 group compared with control group.

In cultured fibroblasts, α-SMA and p-ERK expression were increased in Angptl2 group measured by western blotting analysis.

Conclusions

Our results demonstrated that EAT rather than SAT induces atrial myocardial fibrosis. There is a possibility that Angptl2 effused from EAT plays a part in atrial fibrosis thought EAT paracrine effect.

Acknowledgement/Funding

ONO PHARMACEUTICAL CO

Nationwide Molecular Epidemiology of Measles Virus in Japan Between 2008 and 2017

Genotyping evidence that supports the interruption of endemic measles virus (MV) transmission is one of the essential criteria to be verified in achieving measles elimination. In Japan since 2014, MV genotype analyses have been performed for most of the measles cases in prefectural public health institutes nationwide. With this strong molecular epidemiological data, Japan was verified to have eliminated measles in March, 2015. However, even in the postelimination era, sporadic cases and small outbreaks of measles have been detected repeatedly in Japan. This study investigated the nationwide molecular epidemiology of MV between 2008 and 2017. The 891 strains in the total period between 2008 and 2017 belonged to seven genotypes (D5, D4, D9, H1, G3, B3, and D8) and 124 different MV sequence variants, based on the 450-nucleotide sequence region of the N gene (N450). The 311 MV strains in the postelimination era between 2015 and 2017 were classified into 1, 7, 8, and 32 different N450 sequence variants in D9, H1, B3, and D8 genotypes, respectively. Analysis of the detection period of the individual N450 sequence variants showed that the majority of MV strains were detected only for a short period. However, MV strains, MVs/Osaka.JPN/29.15/ [D8] and MVi/Hulu Langat.MYS/26.11/ [D8], which are named strains designated by World Health Organization (WHO), have been detected in many cases over 2 or 3 years between 2015 and 2017. The WHO-named strains have circulated worldwide, causing outbreaks in many countries. Epidemiological investigation revealed repeated importation of these WHO-named strains into Japan. To demonstrate the elimination status (interruption of endemic transmission) in situations with repeated importation of the same strains is challenging. Nevertheless, the detailed sequence analysis of individual MV strains and chronological analysis of these strains provided sufficient evidence to show that Japan has still maintained its measles elimination status in 2017.

Outbreak of aseptic meningitis caused by echovirus 30 in Kushiro, Japan in 2017

BACKGROUND

Echovirus 30 (E30) is one of the most common causative agents for aseptic meningitis.

OBJECTIVES

In the autumn of 2017, there was an outbreak caused by E30 in Kushiro, Hokkaido, Japan. The aim of this study was to characterize this outbreak.

STUDY DESIGN

Fifty-nine patients were admitted to the Department of Pediatrics, Kushiro Red Cross Hospital (KRCH) with clinical diagnosis of aseptic meningitis. Among those, 36 patients were finally diagnosed as E30-associated aseptic meningitis by the detection of viral RNA using reverse transcription-polymerase chain reaction (RT-PCR) and/or the evidence of more than four-fold rise in neutralizing antibody (NA) titers in the convalescent phase relative to those in the acute phase. We investigated these 36 confirmed cases.

RESULTS

The median age was 6 years (range: 6 months-14 years). The positive signs and symptoms were as follows: fever (100%), headache (94%), vomiting (92%), jolt accentuation (77%), neck stiffness (74%), Kernig sign (29%), and abdominal pain (28%). The median cerebrospinal fluid (CSF) white cell count, neutrophil count, and lymphocyte count were 222/μL (range: 3-1434/μL), 144/μL (range: 1-1269/μL), and 85/μL (range: 2-354/μL), respectively. Although the detected viral genes demonstrated same cluster, they were different from E30 strains observed in Japan between 2010 and 2014.

CONCLUSION

We mainly showed clinical and virological features of the E30-associated aseptic meningitis outbreak that occurred in Kushiro. To prevent further spread of E30 infection, continuous surveillance of enterovirus (EV) circulation and standard precautions are considered essential.

Factors associated with a positive willingness to practise oral health care in the future amongst oral healthcare and nursing students

OBJECTIVES

The purpose of this study was to identify the weak points in the knowledge and attitudes of first-year oral health care and nursing students towards oral health care and to identify the factors associated with their positive willingness to practise oral health care after becoming a health professional in order to develop oral healthcare curricula.

MATERIALS AND METHODS

The subjects were 88 first-year dental students (DSs), 64 dental hygiene students (DHSs) and 119 nursing students (NSs) enrolled in schools in Japan, as of April 2017. A questionnaire was distributed to subjects in each school to assess their knowledge and attitudes towards oral health care.

RESULTS

Less than half knew that oral health care was also provided in cancer hospitals, hospices, acute care hospitals, maternity wards and psychiatric wards. Only 46.2% knew that oral health care was effective in the prevention of aspiration pneumonia. The level of knowledge and attitudes in NSs regarding oral health care were likely to be lowest amongst the student groups. Only NSs' high interest towards oral health care was associated with their positive willingness to practise oral health care in the future although oral health students' high perceptions and interest regarding oral health care were associated with the willingness.

CONCLUSION

This study showed oral healthcare and nursing students' weak points regarding their attitudes and knowledge of oral health care at early stages. Oral health academic staff and professionals should develop effective oral healthcare curricula for oral healthcare students and help nursing staff develop a collaborative nursing oral healthcare curriculum to motivate nursing students.

Hepatitis E outbreak at a nursing home for aged people in Hokkaido, Japan, between February and March 2016

BACKGROUND

Infection with hepatitis E virus (HEV) genotypes 3 and 4 are usually asymptomatic but can occasionally result in life-threatening acute hepatitis. To date, only sporadic cases together with a few outbreaks have been documented. Seroprevalence studies with assays for the detection of HEV IgG antibodies, suggest that HEV is more prevalent than previously thought, even in non-endemic regions.

OBJECTIVES

The aim of this study was to characterize an outbreak of hepatitis E (HE) in a nursing home for aged people between February and March 2016.

STUDY DESIGN

After the identification of two cases living in the same nursing home, the presence of antibodies against HEV and HEV RNA were examined in serum samples collected from the other residents and staff members to identify any additional cases. An epidemiological investigation was also carried out.

RESULTS

Only 4 patients showed mild symptoms such as anorexia, abdominal pain and fatigue. Among the 125 persons tested, 28 residents and one dietitian were confirmed positive for anti-HEV IgA or IgM antibodies, and/or HEV RNA. Eight samples had only IgG antibodies. Finally, 22 cases were notified with HE on the basis of the presence of IgA antibodies. All HEV isolates obtained were 99.8-100% identical and belonged to genotype 3.

CONCLUSION

HEV infections seem to be under-reported or underestimated possibly due to cases being generally asymptomatic. Testing for the presence of both anti-HEV antibodies and HEV RNA would be beneficial for both the comprehensive diagnosis of HE infections and the prevention of further infections.

Amoebal endosymbiont Neochlamydia protects host amoebae against Legionella pneumophila infection by preventing Legionella entry

Acanthamoeba isolated from environmental soil harbors the obligate intracellular symbiont Neochlamydia, which has a critical role in host amoebal defense against Legionella pneumophila infection. Here, by using morphological analysis with confocal laser scanning fluorescence microscopy and transmission electron microscopy, proteome analyses with two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) and liquid chromatography-mass spectrometry (LC/MS), and transcriptome analysis with DNA microarray, we explored the mechanism by which the Neochlamydia affected this defense. We observed that when rare uptake did occur, the symbiotic amoebae allowed Legionella to grow normally. However, the symbiotic amoebae had severely reduced uptake of Legionella when compared with the aposymbiotic amoebae. Also, in contrast to amoebae carrying the endosymbiont, the actin cytoskeleton was significantly disrupted by Legionella infection in aposymbiotic amoebae. Furthermore, despite Legionella exposure, there was little change in Neochlamydia gene expression. Taken together, we concluded that the endosymbiont, Neochlamydia prevents Legionella entry to the host amoeba, resulting in the host defense against Legionella infection.

Molecular Epidemiology of Rubella Virus Strains Detected Around the Time of the 2012-2013 Epidemic in Japan

A nationwide rubella epidemic occurred from 2012 to 2013 in Japan, resulting in around 17,000 rubella cases and the birth of 45 infants with congenital rubella syndrome. The aim of this study was to genetically characterize the rubella viruses (RVs) circulating around the time of the epidemic in Japan. In total, 221 RV strains detected from 14 prefectures in Japan between 2010 and 2014 were sequenced in the 739 nucleotide-window region within the E1 gene. The virus strains were chronologically and geographically characterized into groups based on phylogenetic analysis. Among the 221 strains analyzed, 192 (87%), 26 (12%), and 3 (1%) strains were classified into genotypes 2B, 1E, and 1J, respectively. The majority (n = 184) of the genotype 2B strains belonged to lineage 2B-L1 and shared nucleotide homology with the strains detected in Southeast and East Asian countries. Phylogenetic analyses demonstrated that at least six distinct clusters of RV strains (clusters 1-6) induced outbreaks in Japan between 2010 and 2014. Among them, strains from clusters 3, 4, and 6 circulated almost simultaneously during 2012-2013. The cluster 3 strains circulated locally, whereas strains from cluster 4 spread nationwide. The findings suggest that RVs were introduced into Japan many times from neighboring countries. The 2012-2013 epidemic was a complex of outbreaks induced by at least three clusters of RV strains.

Detection of Measles Virus Genotypes B3, D4, D5, D8, and H1 in the Surveillance System in Hokkaido, Japan, 2006-2015, the Last Decade toward the Elimination

Measles is an acute and highly contagious disease caused by measles virus (MeV). The government of Japan, following the last epidemic in 2007 and 2008, which was caused by genotype D5 strains, introduced a catch-up-vaccination program for teenagers during Japan fiscal years 2008-2012 and a mandatory case-based reporting system for the nationwide elimination. Furthermore, laboratory confirmation of measles cases by genotyping of isolates has been performed to clarify the source of infection and support the interruption of measles cases. Owing to these preventive measures, the number of measles cases has been steadily decreasing after the last epidemic. In March 2015, Japan was internationally verified as having achieved measles elimination by the World Health Organization Regional Office for the Western Pacific. The continuous elimination of measles and high levels of vaccination coverage for MeV have been maintained nationally. However, imported or import-associated cases of measles have sporadically occurred during this time. After the last nationwide epidemic, 17 imported or import-associated measles cases (MeV strains identified as genotypes H1, D4, D8, and B3) were reported in Hokkaido, the northern islands of Japan. In this study, we present the occurrence of measles and surveillance activities in Hokkaido during 2006-2015.

Evaluation of sensitivity of TaqMan RT-PCR for rubella virus detection in clinical specimens

BACKGROUND

An easy and reliable assay for detection of the rubella virus is required to strengthen rubella surveillance. Although a TaqMan RT-PCR assay for detection of the rubella virus has been established in Japan, its utility for diagnostic purposes has not been tested.

OBJECTIVES

To allow introduction of the TaqMan RT-PCR into the rubella surveillance system in Japan, the sensitivity of the assay was determined using representative strains for all genotypes and clinical specimens.

STUDY DESIGN

The detection limits of the method for individual genotypes were examined using viral RNA extracted from 13 representative strains. The assay was also tested at 10 prefectural laboratories in Japan, designated as local reference laboratories for measles and rubella, to allow nationwide application of the assay.

RESULTS

The detection limits and amplification efficiencies of the assay were similar among all the representative strains of the 13 genotypes. The TaqMan RT-PCR could detect approximately 90% of throat swab and urine samples taken up to 5days of illness. These samples were determined positive by a highly sensitive nested RT-PCR.

CONCLUSIONS

The TaqMan RT-PCR could detect at least 10 pfu of rubella virus. Although the sensitivity was somewhat lower than that of the conventional nested RT-PCR, the TaqMan RT-PCR could be more practical to routine tests for rubella laboratory diagnosis and detection in view of the rapid response and reducing risks of contamination.

Recent progress toward measles elimination in Hokkaido, Japan, during 2011-2012

Laboratory diagnoses for measles were performed in a total of 97 cases in Hokkaido, Japan, during 2011-2012. Two patients were confirmed to be positive for measles virus (MV), both of whom lived in the Iburi district of Hokkaido. Molecular analysis of the nucleotide sequences of the nucleoprotein (N) gene revealed that these 2 strains had high homology with each other and belonged to the genotype D8. The onset interval of these cases and epidemiological data suggested that MV transmission had occurred between them and then terminated. Phylogenetic analysis of the N gene revealed that the strains identified in Hokkaido were classified into a cluster that contained many genotype D8 strains that were detected within a large area of Japan. Eventually, 9 cases were officially reported as measles. However, other than the abovementioned 2 cases, no genetic information regarding MV was obtained. In future, further active surveillance combined with the genetic investigation should be required in all suspected measles cases to verify the elimination status.

Epidemiology and laboratory diagnoses of rubella in Hokkaido district during the Nationwide Outbreak in Japan, 2011-2013

We report the epidemiology and laboratory diagnostic results of rubella cases from 2011 to 2013 in Hokkaido district, Japan. A total of 150 cases were officially reported as rubella; 102 (68%) involved males and 48 (32%) involved females. The highest proportion of cases were notified in 40-49-year-old age group among males and the 20-29-years-old age group among females. Forty-six cases (25 males and 21 females) had not been vaccinated, and 17 had been vaccinated, whereas 87 had the unknown vaccination status. Eighty-three cases (55.3%) showed the 3 typical principal rubella symptoms (fever, rash, and lymphadenopathy). Seven, 11, 92, and 40 cases were identified in the northern, eastern, central, and southern areas of Hokkaido district, respectively. In the central and southern areas of Hokkaido district, endemic rubella transmissions were indicated by both the epidemiological survey and molecular analyses. However, these outbreaks terminated spontaneously and did not expand to other areas of Hokkaido district. Fortunately, no congenital rubella syndrome (CRS) cases were reported during this observation period. However, to control virus transmission, prevent CRS, and maintain the routine vaccination program, the immediate introduction of an immunization strategy is required for susceptible individuals, particularly young adults.

Oscillating thrombi in bilateral extracranial internal carotid arteries demonstrated on ultrasonography: two autopsy cases of cardioembolic stroke

We herein report two autopsy cases of severe cardioembolic stroke with oscillating thrombi in the bilateral extracranial internal carotid arteries (ICAs) demonstrated on carotid ultrasonography performed on admission. An autopsy study of case 1 conducted on the third hospital day revealed no thrombi, while that of case 2 conducted on the 42nd hospital day revealed red thrombi in the extracranial ICAs. Our postmortem studies confirm that oscillating thrombi may be seen in the region of blood stasis caused by occlusion of the distal portion of the ICA, thus reflecting a pre-state of thrombus formation.

Usefulness of the rapid determination system of viral genome sequences in human stool specimens

The rapid determination system of viral genome sequences (the RDV method) consists of detecting and determining the nucleotide sequences of viral genomes without using specific primers. To evaluate the usefulness of the RDV method, the detection of human norovirus (NV) genomes in stool specimens was investigated. In addition, the effect of nuclease treatment of the process was examined. A total of 23 human stool specimens were used, all of which were collected from patients with acute viral gastroenteritis, and were shown to contain NV genomes and also determined the cDNA copy numbers by the real-time reverse transcriptase-polymerase chain reaction. NV genomes were detected by the RDV method with nuclease treatment in nine specimens containing cDNA copies ranging between 6.2×10(9) and 9.8×10(11)/g stool. In contrast, NV genome was found by the method in 15 specimens without nuclease treatment and the number of NV cDNA copies ranged between 1.2×10(6) and 9.8×10(11)/g stool. These results suggest that the RDV method has potential for detecting viral genomes in stool specimens. The procedure without a step of nuclease treatment appears to be sensitive.