Improvement of the mismatch amplification mutation assay-PCR for discrimination between Streptococcus suis serotypes 2 and 1/2

A mismatch amplification mutation assay (MAMA)-PCR, which detects a single-nucleotide polymorphism contributed to serological difference between Streptococcus suis serotypes 2 and 1/2, is used to discriminate between these serotypes. The present study reports unusual serotype 1/2 isolates untypable by the MAMA-PCR and improvement of the MAMA-PCR for typing such isolates.

Impact of BNP level in patients with heart failure on major bleeding events after percutaneous coronary intervention

Aims

The Academic Research Consortium for High Bleeding Risk (ARC-HBR) presents a bleeding risk assessment in antithrombotic therapy for patients post percutaneous coronary intervention (PCI). In Japanese patients, heart failure (HF), peripheral vascular disease, and frailty are established as bleeding risk factors in addition to ARC-HBR. However, it is unknown whether left ventricular function or severity of HF is associated with HBR. The aim of this study was to investigate the association between the severity of HF measured by BNP and future bleeding events after PCI.

Methods

Clinical Deep Data Accumulation System (CLIDAS), a multicenter database with 7 tertiary medical hospitals in JAPAN, was developed to collect data directly for patient characteristics, medications, laboratory test, physiological test, cardiac catheterization and PCI treatment in electronic medical records using Standardized Structured Medical Information eXchange Extended Storage (SS-MIX). This retrospective analysis using CLIDAS database included 7160 patients who underwent PCI during April 2014 and March 2020 in the participating hospitals and also who have completed 3-year follow-up were divided into two groups: No HF (n=6645) and HF (n=515). HF patients were furthermore divided based on high BNP (≥100 pg/ml) group (n=384) and low BNP (<100 pg/ml) group (n=131). Primary outcome was defined as bleeding events according to the moderate and severe bleeding in the GUSTO classification. In addition, secondary endpoint was major adverse cardiovascular events (MACE) defined as a composite of cardiac death, myocardial infraction and stroke.

Results

Multivariable Cox regression adjusted for age, sex, BMI, acute coronary syndrome, hypertension, diabetes, dyslipidemia, chronic kidney disease, hemodialysis, previous PCI, previous coronary artery bypass grafting, prior myocardial infraction, prior stroke, prior atrial fibrillation, prior PVD, left main trunk disease, multivessel disease, and anticoagulants use showed that HF with high BNP was significantly associated with bleeding events (hazard ratio [HR], 1.66; 95% confidence interval [CI], 1.10–2.50), MACE (HR, 2.16; 95% CI, 1.60–2.90), and all-cause death (HR, 1.74; 95% CI, 1.30–2.33), but not HF with low BNP.

Conclusions

The CLIDAS real-world database revealed that HF with high BNP was associated with future bleeding events, suggesting that bleeding risk might be altered depending on severity of HF.

Funding Acknowledgement

Type of funding sources: None.

Hyperuricemia predicts worse prognosis in patients with chronic coronary syndrome after percutaneous coronary intervention: insights from Japanese real-world database using a storage system

Background

The relationship between hyperuricemia (HUA) and cardiovascular disease was observed in some epidemiological studies. However, the association between HUA and chronic coronary syndrome (CCS) after percutaneous coronary intervention (PCI) is not fully elucidated.

Purpose

The purpose of this study was to investigate the prognostic impact of HUA in patients with CCS after PCI.

Methods

This study is a retrospective, multicenter, observational study. We developed the Clinical Deep Data Accumulation System (CLIDAS), which consists of 6 university hospitals and the national cardiovascular center in Japan, directly obtains clinical data including patients background, laboratory data, echocardiogram, electrocardiogram, cardiac catheterization report, prescription, and long-term outcome from electronic medical records. A total of 9936 consecutive patients after PCI were analyzed. Of them, 5138 patients with CCS after PCI during April 2013 and March 2019 were analyzed, and divided into HUA group (patients with HUA at baseline, n=1724) and non-HUA group (patients without HUA at baseline, n=3414). HUA was defined as a serum uric acid levels ≥7.0 mg/dL for men or ≥6.0 mg/dL for women and/or taking urate-lowering drugs. The primary outcome was the major cardiovascular events (MACE) defined as being the composite of cardiovascular death, myocardial infarction, and hospitalization for heart failure.

Results

The median follow-up duration was 910 days (interquartile range: 307–1479 days). The proportion of male (78% vs. 78%) and age (71±11 vs. 71±10) were similar between the HUA and the non-HUA groups. The prevalence of hypertension (87% vs. 82%), atrial fibrillation (9% vs. 5%), and history of previous hospitalization for heart failure (15% vs. 6%) and baseline creatinine value (1.8±2.3 vs. 1.5±2.0 mg/dL) were significantly higher in the HUA group. In contrast, the prevalence of diabetes (43% vs. 48%) was significantly lower in the HUA group. The incidence of MACE was significantly higher in the HUA group than in the non-HUA group (13.1% vs. 6.4%, log rank P<0.001). Multivariate Cox regression analyses revealed that hyperuricemia was significantly associated with MACE (hazard ratio 1.50, 95% confidence interval 1.22–1.84, P<0.001) after controlling for other cardiovascular risk factors.

Conclusion

The real-world database CLIDAS revealed that hyperuricemia was significantly associated with the increase of MACE in patients with CCS after PCI. This result sheds light on the significant role of urate in prediction of prognosis, suggesting the possibility of new therapeutic approaches using urate-lowering drugs or SGLT2 inhibitors for the CCS patients.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Jichi Medical University, Tochigi, Japan, and Kowa Co., Ltd

Suppurative meningoencephalitis and perineuritis caused by Streptococcus gallolyticus in a Japanese Black calf

A 179-day-old calf, which was weak and stunted, showed neurological signs and was euthanized. Postmortem examination revealed extensive and severe cloudy area in the meninges, and pleural pneumonia. Gram-positive cocci were isolated from systemic organs. Biochemical and 16S rRNA gene sequence analyses identified the isolate as Streptococcus gallolyticus, and its subspecies was suggested to be gallolyticus (SGG). The isolate was classified as a novel sequence type (ST115) by the multilocus sequence typing scheme for SGG and showed susceptibility to penicillin, ampicillin, amoxicillin, florfenicol, sulfamethoxazole-trimethoprim, and chloramphenicol. Histopathologically, suppurative meningoencephalitis and perineuritis were detected. As SGG has been isolated solely from a cow with mastitis in Japan, this is the first SGG infection in a calf with suppurative meningoencephalitis and perineuritis in this country.

The relationships among the pulse rate, use of beta-blockers, and prognosis in patients with ischemic heart disease in a real-world database using a storage system

Background

The use of β-blockers has the effect of improving the prognosis of patients with ischemic heart disease (IHD). One of the underlying mechanisms is a decrease in the cardiac load due to a reduction in the heart rate.

Purpose

To clarify the relationships among the pulse rate, the use of β-blockers, and the prognosis in patients with IHD in a multicenter study using a storage system.

Methods

The Clinical Deep Data Accumulation System (CLIDAS) collects (1) basic patient information, prescriptions, and laboratory data from electronic medical records from the Standardized Structured Medical Information eXchange (SS-MIX2) standard storage, and (2) the results of physiological tests, cardiac catheterization, and cardiac catheter intervention reports from the SS-MIX2 extended storage. 8540 cases who underwent cardiac catheterization from 6 university hospitals and the national cardiovascular center in Japan were registered (male: 77%, average age: 70.2 years). We evaluated these patients' pulse rate at admission and at the discharge of cardiac catheterization in 6,598 patients. We divided the pulse rates at discharge into quartiles (Q1: <60, Q2: 60–66, Q3: 67–75, Q4: ≥76 bpm), and we analyzed the relationship between the pulse rate and the prognosis by dividing the patients into the stable angina group (n=2,631) and the acute coronary syndrome (ACS) group (n=2,394). Regarding the use of β-blockers, we compared the pulse rates of the patients taking carvedilol (n=1,728) and those taking bisoprolol (n=2,761) at admission and discharge. Major adverse cardiovascular events (MACE) were defined as cardiovascular death, non-fatal myocardial infarction, unstable angina, heart failure, stroke, and other hospitalized cardiovascular events.

Results

A total of 600 MACEs occurred during an average observation period of 890 days. The incidence of cardiovascular events was significantly higher in the Q4 patients in the stable angina group (hazard ratio 1.79, 95% confidence interval 1.32–2.41, but there was no significant difference among the four pulse rate subgroups in the ACS group. The bisoprolol-treated patients had lower pulse rates at discharge (67.4±12.2 vs. 68.8±11.8 bpm, p<0.001) and a lower percentage of patients in the Q4 group (21.2 vs. 24.9%, p=0.005) compared to the carvedilol-treated patients. The pulse rate at admission was similar in the bisoprolol- and carvedilol-treated patients (74.3±19.3 vs. 73.2±29.5 bpm, p=0.328).

Conclusion

In a real-world database using a storage system, a pulse rate of ≤75 bpm was associated with a good prognosis in patients with ACS. Compared to carvedilol, bisoprolol was associated with a decreased pulse rate at discharge.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Kowa Company, Ltd.

Clinical Deep Data Accumulation System (CLIDAS) reveals lipid paradox in guideline-defined high risk Japanese patients after PCI

Background

Japanese clinical guidelines recommend a stratification of the risks and LDL-cholesterol (LDL-C) treatment goals for patients with coronary artery disease after percutaneous coronary intervention (PCI), i.e. <100 mg/dL for normal risk patients and <70 mg/dL for high risk patients; however, less is known about the association between baseline LDL-C values and long-term prognosis.

Purpose

To investigate the association between LDL-C goals and baseline LDL-C levels in relation to major adverse cardiovascular events (MACE) among high-risk patients after PCI, using a real-world database.

Methods

We developed the Clinical Deep Data Accumulation System (CLIDAS) that acquires clinical data directly from hospital information system, and implemented the system in 6 university hospitals and the national cardiovascular center in Japan. The CLIDAS database accumulates data regarding patient background, laboratory data, prescriptions, electrocardiogram, echocardiogram, PCI report, and long-term prognosis. We retrospectively analyzed 8540 consecutive patients who underwent PCI during April 2014 and March 2020 in participating hospitals, and classified them into the normal risk group (n=3712, 43%) and the high risk group [n=4828, 57%, with any of acute coronary syndrome (ACS), familial hypercholesterolemia (FH), or diabetes with additional risk factor(s)], for which LDL-C goals are <100 mg/dL and <70 mg/dL, respectively, according to the Japanese Atherosclerosis Society guidelines or the diagnosis and prevention of atherosclerotic cardiovascular diseases. The primary outcome was the time to first occurrence of MACE, a composite of cardiovascular death, stroke, myocardial infarction, and coronary revascularization in associations with baseline LDL-C levels and patient background.

Results

Proportion of male (77% vs. 77%) and age (71±11 vs. 70±11) were similar between 2 groups. The prevalence of ACS at the index PCI (0% vs. 62%), FH (0% vs. 2%), hypertension (61% vs. 86%), diabetes (11% vs. 67%), dyslipidemia (73% vs. 84%), hemodialysis (4% vs. 9%), peripheral artery disease (5% vs. 9%), smoking (16% vs. 30%), and prescription of statins (79% vs. 86%) were significantly higher in the high risk group. Among patients in the high risk group, but not in the normal risk group, baseline LDL-C <70 mg/dL was paradoxically associated with higher risk of MACE (P<0.0001 by Log-rank test) (Figure). The Cox proportional hazard model confirmed that the high risk group (risk ratio 1.54, 95% CI [1.31–1.81]), baseline LDL-C <70mg/dL (risk ratio 1.44, 95% CI [1.18–1.75]), baseline age (risk ratio 1.36, 95% CI [1.28–1.45] per 10 year), and prescription of statins (risk ratio 0.80, 95% CI [0.66–0.96]) were significantly associated with the risk of MACE in this population.

Conclusion

The CLIDAS real-world database revealed that baseline low LDL-C paradoxically associated with an increased risk of MACE among guideline-defined high risk patients after PCI.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Jichi Medical University, Tochigi, Japan, and Kowa

Impact of grip strength and balance function on the exercise capacity in pulmonary hypertension

Funding Acknowledgements

Type of funding sources: None.

【Background】

Patients with pulmonary hypertension (PH) suffer from poor exercise capacity due to impaired oxygenation or reduced cardiac output. However, the relationship between exercise capacity and physical functions remains unclear.

【Purpose】

The purpose of this study is to investigate the relationship between exercise capacity and physical functions in pulmonary hypertension.

【Methods】

From February 2018 to June 2020, 94 patients (61.3 ± 14.7 years old, 69.1% females) with group 1/3/4/5 PH underwent cardiac catheterization, 6-minute walking distance (6MWD), and physical function measurements simultaneously. The physical functions was measured using muscle strength (grip strength, knee extension muscle strength), balance function (one leg standing time), and short physical performance battery (SPPB). Exercise capacity was measured by 6MWD. 

【Results】

The study cohort consists of 22/8/60/4 (23.4%/8.5%/63.8%/4.3%) patients with group 1/3/4/5 PH, respectively. The average age of each group was 50.7/64.7/63.1/66.0 years old, respectively. A total of 194 measurements of physical functions were evaluated from 94 patients and employed in multivariate logistic regression analysis using adaptive-LASSO methods with the 6MWD (476.2 ± 107.5m) as a dependent variable. WHO functional class (class II: standardized β=-0.35, 95% confidence interval (CI) [-0.54 - -0.16], p < 0.001), class III: β=-0.60, 95%CI [-0.90 - -0.30], p < 0.001), mixed venous oxygen saturation (SvO2: β=0.11, 95%CI [0.03 - 0.19], p = 0.008), pulmonary vascular resistance (PVR: β=-0.16, 95%CI [-0.25 - -0.07], p < 0.001), grip strength (β=0.20, 95%CI [0.09 - 0.31], p < 0.001), one leg standing time (β=0.10, 95%CI [0.00 - 0.20], p = 0.049) , and 4m gait speed test (β=-0.28, 95%CI [-0.36 - -0.19], p < 0.001) were associated with 6MWD.

【Conclusions】

Grip strength and balance function, as well as SvO2 and PVR, were associated with the exercise capacity in pulmonary hypertension.

Electronic phenotyping of heart failure from a national clinical information database

Introduction

A database of clinical information collected from several medical institutions, including national university hospitals and private hospital groups, and the medical information database network, MID-NET, have been available to the public in Japan since 2018. To analyse clinical events, i.e., to perform electronic phenotyping, it is important to extract data from clinical information correctly, combine multiple pieces of information, and define the target disease. Herein, we investigated a study to find patients with heart failure and validated our findings using MID-NET data.

Methods

A criterion to describe heart failure cases was determined according to clinical guidelines released by the Japanese Circulation Society. The data studied were based on records from April 1–December 31, 2013. The initial rule was based on disease names, examinations, and medications pertaining to heart failure. We extracted and analysed clinical data from MID-NET and found patients with heart failure. Two doctors, including a cardiologist, reviewed the medical records and verified the legitimacy of the cases, following which we calculated precision and recall rates. Next, we examined a method to identify factors to extract true cases correctly using machine learning with XGBoost in R.

Results

A total of 5,282 cases extracted via disease names were related to heart failure. Of these, 2,799 cases corresponding to the initial rule were retrieved, and 200 cases were randomly sampled and assessed. A total of 70 cases were found to be true. Thus, a precision rate of 0.350 and a recall rate of 0.912 were determined. A machine learning method revealed the correlation of heart failure with several factors, including the serum b-type natriuretic peptide (BNP) value, link between commencement date of the disease and actual hospitalization date, and medications for the treatment of heart failure. Using this data, we could determine the conditions contributing to improving the validity of the cases with heart failure. In this manner, patient cases were extracted using the disease name as it is related to heart failure and hospitalisation within two weeks after the commencement date of the disease. Furthermore, the candidates were categorised into three groups according to serum BNP values (high, middle, and low ranges). The high group was labelled “heart failure”, and the low group was excluded. In the middle group, candidates were additionally categorised according to their prescribed medication for heart failure. Our analysis indicated that the precision rate increased to 0.878 while the recall rate decreased to 0.697. The F-measure also increased from 0.506 to 0.777.

Conclusions

To find target cases from a large clinical database, precise electronic phenotyping is required. A machine learning method can enable accurate identification of patients with heart failure. Leveraging large amounts of clinical data may be beneficial for medical research progress.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Agency for Medical Research and Development

Clinical outcomes of patients with diffuse coronary artery disease following physiology-guided treatment strategy: insights from AJIP registry

Background

Physiology-guided treatment strategy improves clinical outcomes of patients with coronary artery disease. However, it has not been fully evaluated whether such guideline-based strategy is useful for patients with diffuse coronary artery disease as well, which is known to be one of the major factors affecting morbidity and mortality.

Purpose

The aim of this study was to clarify clinical outcomes of patients with diffuse coronary artery disease whose treatment strategy was based on coronary physiology.

Methods

From an international multicentre registry of iFR-pullback, consecutive 1067 patients (1185 vessels) with stable angina were included in whom coronary lesions were deferred or revascularized according to the iFR cutoff: 0.89. The physiological pattern of disease was classified according to the iFR-pullback recording as predominantly physiologically diffuse (n=463) or predominantly physiologically focal (n=722). Major adverse cardiovascular events (MACEs), defined as a composite of cardiac death, non-fatal myocardial infarction, and ischemia-driven target lesion revascularization during follow-up period, were compared between diffuse and focal groups, in both deferred and revascularized groups, respectively.

Results

Mean age was 67.1±10.7 years and 75.8% of patients were men. Median iFR was 0.88 (interquartile range: 0.80 to 0.92). At a median follow-up period of 18 months, no significant differences in MACEs were found between diffuse and focal groups, in both iFR-based deferred and revascularized groups. In the deferred group (n=480), MACEs occurred in 6.9% patients (15/217) in the diffuse group and 8.0% patients (21/263) in the focal group (p=0.44). In the revascularized group (n=705), MACEs occurred in 8.9% patients (22/246) in the diffuse group and 7.2% patients (33/459) in the focal group (p=0.49).

Conclusions

Despite potentially higher risks in patients with diffuse coronary artery disease, clinical outcomes of those patients were comparable to those of patients without diffuse disease, as long as treatment strategy was based on the physiology guidance, which is globally recommended by international guidelines.

Funding Acknowledgement

Type of funding source: None

Publisher Correction: A weak topological insulator state in quasi-one-dimensional bismuth iodide

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Devil's staircase transition of the electronic structures in CeSb

Solids with competing interactions often undergo complex phase transitions with a variety of long-periodic modulations. Among such transition, devil's staircase is the most complex phenomenon, and for it, CeSb is the most famous material, where a number of the distinct phases with long-periodic magnetostructures sequentially appear below the Néel temperature. An evolution of the low-energy electronic structure going through the devil's staircase is of special interest, which has, however, been elusive so far despite 40 years of intense research. Here, we use bulk-sensitive angle-resolved photoemission spectroscopy and reveal the devil's staircase transition of the electronic structures. The magnetic reconstruction dramatically alters the band dispersions at each transition. Moreover, we find that the well-defined band picture largely collapses around the Fermi energy under the long-periodic modulation of the transitional phase, while it recovers at the transition into the lowest-temperature ground state. Our data provide the first direct evidence for a significant reorganization of the electronic structures and spectral functions occurring during the devil's staircase.

Difference in the antibacterial action of epigallocatechin gallate and theaflavin 3,3'-di-O-gallate on Bacillus coagulans

AIMS

To study the mechanism of the antibacterial action of tea polyphenols such as catechins and theaflavins against Bacillus coagulans, and the interaction of epigallocatechin gallate (EGCg) or theaflavin 3,3'-di-O-gallate (TFDG) with the surface of B. coagulans cells was investigated.

METHODS AND RESULTS

The antibacterial activities of EGCg and TFDG against B. coagulans cells were measured by counting of the viable cells after the mixing with each polyphenol. Bactericidal effect of TFDG was shown at the concentration of greater than or equal to 62·5 mg l^-1 ; however, at the same concentration, EGCg did not. According to the results of two dimensional (2D)-electrophoresis analysis, TFDG seemed to interact with cytoplasmic membrane proteins. The activity of the glucose transporters of the cells decreased 40% following the treatment with TFDG of 62·5 mg l^-1 ; however, this decrease was only slight in case of EGCg. This result was in accordance with the strength of their bactericidal activities.

CONCLUSION

Our results suggest that the direct interaction between membrane proteins and TFDG is an important factor in the antibacterial activity of polymerized catechins, affecting their functions and leading to cell death.

SIGNIFICANCE AND IMPACT OF THE STUDY

Tea polyphenols can effectively use the prevention of product spoilage in the food and beverage industry.

Radial Spin Texture in Elemental Tellurium with Chiral Crystal Structure

The chiral crystal is characterized by a lack of mirror symmetry and inversion center, resulting in the inequivalent right- and left-handed structures. In the noncentrosymmetric crystal structure, the spin and momentum of electrons are expected to be locked in the reciprocal space with the help of the spin-orbit interaction. To reveal the spin textures of chiral crystals, we investigate the spin and electronic structure in a p-type semiconductor, elemental tellurium, with the simplest chiral structure by using spin- and angle-resolved photoemission spectroscopy. Our data demonstrate that the highest valence band crossing the Fermi level has a spin component parallel to the electron momentum around the Brillouin zone corners. Significantly, we have also confirmed that the spin polarization is reversed in the crystal with the opposite chirality. The results indicate that the spin textures of the right- and left-handed chiral crystals are hedgehoglike, leading to unconventional magnetoelectric effects and nonreciprocal phenomena.

P1259Right atrial low voltage zone as a novel predictor of sinus node dysfunction in patients with non-paroxysmal atrial fibrillation

Background

Although sinus node dysfunction (SND) coexists with atrial fibrillation (AF) in some cases, SND in patients with Non-paroxysmal AF (Non-PAF) could not be estimated in conventional electrophysiological study.

Atrial low voltage zone (LVZ), which may be surrogate for atrial fibrosis, is although reported to present in patients with Non-PAF, the association between SND and right atrial LVZ (RA-LVZ) has not been fully evaluated. The aim of the present study was to assess the relationship between SND and RA-LVZ in patients with Non-PAF.

Method

Eighty-six Non-PAF patients underwent high density voltage mapping of right atrium (RA) during AF before ablation procedure. We defined LVZ as that with electrogram amplitude <0.1 mV in order to delineate strongly damaged area in RA. We evaluated the surface are of the RA-LVZ in Non-PAF patients with and without SND.

Results

Twenty-seven of 86 patients (31.4%) presented with SND after AF termination. There were no significant differences between patients with and without SND in variables such as age, sex, AF duration, left atrial diameter, and left ventricular ejection fraction. The mean value of RA-LVZ of all the patients was 12.1±11.4%, and RA-LVZ was significantly larger in patients with SND than in those without SND (22.8±14.6 vs 7.2±4.2%; P<0.001). In multivariate logistic regression analysis for the incidence of subsequent pacemaker implantation (PMI), only RA-LVZ was a significant predictor of subsequent PMI (odd ratio 1.306; 95% confidence interval 1.159 - 1.473; P<0.001). Receiving-operating characteristic curve for PMI following ablation procedure indicated cut-off value 10.5% for RA-LVZ with 85.2% sensitivity and 88.1% specificity (area under curve = 0.924, P<0.001). Kaplan-Meier analysis of the incidence of PMI after AF termination showed that freedom from pacemaker implantation was significantly better in patients with RA-LVA <10.5% than in those with RA-LVZ ≥10.5% (log-rank test; P<0.001).

Conclusions

Broad RA-LVZ measured during AF was strongly associated with SND and PMI after AF termination in patients with Non-PAF. Evaluation of RA-LVZ during AF could be a potential target in predicting SND requiring PMI in patients with Non-PAF.

Isolation of induced pluripotent stem cell-derived endothelial progenitor cells from sac-like structures

Transplanted endothelial progenitor cells (EPCs) repair blood vessels and exert regenerative effects on disorders such as lower limb ischemia. EPCs serve as a model for pathophysiological and pharmacokinetic studies, which is important for drug discovery. However, primary human EPCs are phenotypically unstable, which limits their clinical utility. Therefore, we employed human induced pluripotent stem (iPS) cells to circumvent this problem. Here we focused on human iPS cell-derived sac-like structures (iPS-sacs), which contain endothelial lineage cells and hematopoietic lineage cells. Previous studies isolated only hematopoietic lineage cells from iPS-sacs. Therefore, here we attempted to isolate EPCs. However, iPS-sacs generated by a published protocol did not contain sufficient EPCs. Therefore, to generate iPS-sacs highly enriched in EPCs, we added the glycogen synthase kinase 3 beta (GSK3β) inhibitor CHIR-99021 to the culture medium early during differentiation. The cells rapidly differentiated into mesoderm to yield abundant EPCs, and CHIR-99021 increased the proportion of EPCs contained in iPS-sacs. EPCs, which were purified using anti-platelet endothelial cell adhesion molecule (PECAM1) antibody-conjugated beads, expressed markers of immature endothelial cells. Purified EPCs formed tube-like structures and incorporated acetylated low density lipoprotein (Ac-LDL), reflecting endothelial phenotypes. The simple method described here will likely improve regenerative medicine and facilitate basic studies on the endothelial lineage.

SurePath® LBC improves the diagnostic accuracy of intrahepatic and hilar cholangiocarcinoma

INTRODUCTION

The current study aimed to compare cytology using SurePath^® (SP)-LBC and biliary tissue histology (BTH) for the diagnosis of biliary disease.

METHODS

Between January 2014 and December 2016, 57 patients underwent endoscopic retrograde cholangiopancreatography for the diagnosis of biliary disease. Biliary cytological samples were processed using SP-LBC and subsequently BTH was performed. A final diagnosis was confirmed by surgery (23 malignant cases) and clinical follow-up (34 benign and malignant cases): 18 extrahepatic cholangiocarcinoma; 17 intrahepatic/hilar cholangiocarcinoma (intra/H-CC); eight other malignant disease; and 14 benign biliary disease. The diagnoses made using SP-LBC and BTH were classified into four categories: (1) benign; (2) indeterminate; (3) suspicious for malignancy/malignant; and (4) inadequate. In addition, diagnostic accuracy was compared between SP-LBC and BTH.

RESULTS

Although 23% (13/57) of BTH samples were classified as inadequate, all SP-LBC cases were classified as adequate. Among 43 malignant cases, 11 normal, four indeterminate and 28 suspicious for malignancy/malignant were found using SP-LBC (26%, 9% and 65%, respectively), in contrast to 10 inadequate, nine normal, 10 indeterminate and 14 suspicious for malignancy/malignant observed using BTH (23%, 21%, 23%, and 33%, respectively). The identification of malignant cells was strikingly different between SP-LBC and BTH. Furthermore, limited to intra/H-CC, accuracy was significantly higher using SP-LBC than using BTH (P < .001).

CONCLUSIONS

SP-LBC of the biliary tract is a useful and reliable method for diagnosing biliary malignant disease and has an advantage over BTH for detecting malignant cells and accurately diagnosing intra/H-CC.

Evidence for magnetic Weyl fermions in a correlated metal

Weyl fermions have been observed as three-dimensional, gapless topological excitations in weakly correlated, inversion-symmetry-breaking semimetals. However, their realization in spontaneously time-reversal-symmetry-breaking phases of strongly correlated materials has so far remained hypothetical. Here, we report experimental evidence for magnetic Weyl fermions in Mn₃Sn, a non-collinear antiferromagnet that exhibits a large anomalous Hall effect, even at room temperature. Detailed comparison between angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations reveals significant bandwidth renormalization and damping effects due to the strong correlation among Mn 3d electrons. Magnetotransport measurements provide strong evidence for the chiral anomaly of Weyl fermions-namely, the emergence of positive magnetoconductance only in the presence of parallel electric and magnetic fields. Since weak magnetic fields (approximately 10 mT) are adequate to control the distribution of Weyl points and the large fictitious fields (equivalent to approximately a few hundred T) produced by them in momentum space, our discovery lays the foundation for a new field of science and technology involving the magnetic Weyl excitations of strongly correlated electron systems such as Mn₃Sn.

Vascularized Tissue-Engineered Model for Studying Drug Resistance in Neuroblastoma

Neuroblastoma is a vascularized pediatric tumor derived from neural crest stem cells that displays vasculogenic mimicry and can express a number of stemness markers, such as SOX2 and NANOG. Tumor relapse is the major cause of succumbing to this disease, and properties attributed to cancer stem-like cells (CSLC), such as drug-resistance and cell plasticity, seem to be the key mechanisms. However, the lack of controllable models that recapitulate the features of human neuroblastoma limits our understanding of the process and impedes the development of new therapies. In response to these limitations, we engineered a perfusable, vascularized in vitro model of three-dimensional human neuroblastoma to study the effects of retinoid therapy on tumor vasculature and drug-resistance.

METHODS

The in vitro model of neuroblastoma was generated using cell-sheet engineering and cultured in a perfusion bioreactor. Firstly, we stacked three cell sheets containing SKNBE(2) neuroblastoma cells and HUVEC. Then, a vascular bed made of fibrin, collagen I and HUVEC cells was placed onto a collagen-gel base with 8 microchannels. After gelling, the stacked cell sheets were placed on the vascular bed and cultured in the perfusion bioreactor (perfusion rate: 0.5 mL/min) for 4 days. Neuroblastoma models were treated with 10μM isotretionin in single daily doses for 5 days.

RESULTS

The bioengineered model recapitulated vasculogenic mimicry (vessel-like structure formation and tumor-derived endothelial cells-TECs), and contained CSLC expressing SOX2 and NANOG. Treatment with Isotretinoin destabilized vascular networks but failed to target vasculogenic mimicry and augmented populations of CSLCs expressing high levels of SOX2. Our results suggest that CSLCs can transdifferentiate into drug resistant CD31⁺-TECs, and reveal the presence of an intermediate state STEC (stem tumor-derived endothelial cell) expressing both SOX2 and CD31.

CONCLUSION

Our results reveal some roles of SOX2 in drug resistance and tumor relapse, and suggest that SOX2 could be a therapeutic target in neuroblastoma.

Orbital-Dependent Band Narrowing Revealed in an Extremely Correlated Hund's Metal Emerging on the Topmost Layer of Sr_{2}RuO_{4}

We use a surface-selective angle-resolved photoemission spectroscopy and unveil the electronic nature on the topmost layer of Sr_{2}RuO_{4} crystal, consisting of slightly rotated RuO_{6} octahedrons. The γ band derived from the 4d_{xy} orbital is found to be about three times narrower than that for the bulk. This strongly contrasts with a subtle variation seen in the α and β bands derived from the one-dimensional 4d_{xz/yz}. This anomaly is reproduced by the dynamical mean-field theory calculations, introducing not only the on-site Hubbard interaction but also the significant Hund's coupling. We detect a coherence-to-incoherence crossover theoretically predicted for Hund's metals, which has been recognized only recently. The crossover temperature in the surface is about half that of the bulk, indicating that the naturally generated monolayer of reconstructed Sr_{2}RuO_{4} is extremely correlated and well isolated from the underlying crystal.

Slater to Mott Crossover in the Metal to Insulator Transition of Nd_{2}Ir_{2}O_{7}

We present an angle-resolved photoemission study of the electronic structure of the three-dimensional pyrochlore iridate Nd_{2}Ir_{2}O_{7} through its magnetic metal-insulator transition. Our data reveal that metallic Nd_{2}Ir_{2}O_{7} has a quadratic band, touching the Fermi level at the Γ point, similar to that of Pr_{2}Ir_{2}O_{7}. The Fermi node state is, therefore, a common feature of the metallic phase of the pyrochlore iridates. Upon cooling below the transition temperature, this compound exhibits a gap opening with an energy shift of quasiparticle peaks like a band gap insulator. The quasiparticle peaks are strongly suppressed, however, with further decrease of temperature, and eventually vanish at the lowest temperature, leaving a nondispersive flat band lacking long-lived electrons. We thereby identify a remarkable crossover from Slater to Mott insulators with decreasing temperature. These observations explain the puzzling absence of Weyl points in this material, despite its proximity to the zero temperature metal-insulator transition.

Quadratic Fermi node in a 3D strongly correlated semimetal

Strong spin–orbit coupling fosters exotic electronic states such as topological insulators and superconductors, but the combination of strong spin–orbit and strong electron–electron interactions is just beginning to be understood. Central to this emerging area are the 5d transition metal iridium oxides. Here, in the pyrochlore iridate Pr₂Ir₂O₇, we identify a non-trivial state with a single-point Fermi node protected by cubic and time-reversal symmetries, using a combination of angle-resolved photoemission spectroscopy and first-principles calculations. Owing to its quadratic dispersion, the unique coincidence of four degenerate states at the Fermi energy, and strong Coulomb interactions, non-Fermi liquid behaviour is predicted, for which we observe some evidence. Our discovery implies that Pr₂Ir₂O₇ is a parent state that can be manipulated to produce other strongly correlated topological phases, such as topological Mott insulator, Weyl semimetal, and quantum spin and anomalous Hall states.

5d transition metal iridates provide a platform to study the combined effects of strong spin orbit coupling and strong electronic correlations. Here, the authors find a quadratic band touching in the band structure of Pr₂Ir₂O₇, suggesting it may be tuned to form various strongly correlated topological phases.

Sudden infant death due to Lactococcal infective endocarditis

Infective endocarditis (IE) of infants is rare, most of which occur associated with congenital heart disease or its cardiac surgery. We experienced a case of sudden death of a four-month-old male infant without congenital heart disease. It was elucidated by postmortem examination that the dead had suffered severe IE, which led him to death. In the microbiological genetic analysis using histological section, the pathogen causing inflammation in the present case was identified as Lactococcus lactis subspecies, although Staphylococci have been reported to be common and important one. Previously reported infectious diseases by Lactococcus lactis subspecies were all adult cases and this is the first report of an infantile death due to Lactococcal IE according to our knowledge. Any fatal disease may be included in sudden death cases targeted for forensic autopsy, even if it is rare. It is expected for forensic pathologists that they note such case and share each experience among themselves and other medical fields to develop a strategy for prevention.