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

Synthesis and Biological Evaluation of Novel 2-(Benzofuran-2-yl)-chromone Derivatives for In Vivo Imaging of Prion Deposits in the Brain

Prion diseases are fatal neurodegenerative disorders caused by the deposition of scrapie prion protein aggregates (PrP^Sc) in the brain. We previously reported that styrylchromone (SC) and benzofuran (BF) derivatives have potential as imaging probes for PrP^Sc. To further improve their properties, we designed and synthesized 2-(benzofuran-2-yl)-chromone (BFC) derivatives hybridized with SC and BF backbones as novel single-photon emission computed tomography probes for the detection of cerebral PrP^Sc deposits. Recombinant mouse prion protein (rMoPrP) aggregates and mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice were used to evaluate the binding properties of BFC derivatives to PrP^Sc. The BFC derivatives exhibited high binding affinities (equilibrium dissociation constant [K_d] = 22.6-47.7 nM) for rMoPrP aggregates. All BFC derivatives showed remarkable selectivity against amyloid beta aggregates. Fluorescence microscopy confirmed that the fluorescence signals of the BFC derivatives corresponded to the antibody-positive deposits of PrP^Sc in mBSE-infected mouse brains. Among the BFC derivatives, [¹²⁵I]BFC-OMe and [¹²⁵I]BFC-NH₂ exhibited high brain uptake and favorable washout from the mouse brain. In vitro autoradiography demonstrated that the distribution of [¹²⁵I]BFC-OMe in the brain tissues of mBSE-infected mice was colocalized with PrP^Sc deposits. Taken together, BFC derivatives appear to be promising prion imaging probes.

Synthesis and Characterization of Hydroxyethylamino- and Pyridyl-Substituted 2-Vinyl Chromone Derivatives for Detection of Cerebral Abnormal Prion Protein Deposits

Prion diseases are fatal neurodegenerative diseases characterized by the deposition of abnormal prion protein aggregates (PrP^Sc) in the brain. In this study, we developed hydroxyethylamino-substituted styrylchromone (SC) and 2-(2-(pyridin-3-yl)vinyl)-4H-chromen-4-one (VPC) derivatives for single-photon emission computed tomography (SPECT) imaging of PrP^Sc deposits in the brain. The binding affinity of these compounds was evaluated using recombinant mouse prion protein (rMoPrP) aggregates, which resulted in the inhibition constant (K_i) value of 61.5 and 88.0 nM for hydroxyethyl derivative, (E)-2-(4-((2-hydroxyethyl)amino)styryl)-6-iodo-4H-chromen-4-one (SC-NHEtOH) and (E)-2-(4-((2-hydroxyethyl)(methyl)amino)styryl)-6-iodo-4H-chromen-4-one (SC-NMeEtOH), respectively. However, none of the VPC derivatives showed binding affinity for the rMoPrP aggregates. Fluorescent imaging demonstrated that the accumulation pattern of SC-NHEtOH matched with the presence of PrP^Sc in the brain slices from mouse-adapted bovine spongiform encephalopathy-infected mice. A biodistribution study of normal mice indicated low initial brain uptake of [¹²⁵I]SC-NHEtOH (0.88% injected dose/g (% ID/g) at 2 min) despite favorable washout from the brain (0.26% ID/g, at 180 min) was displayed. [¹²⁵I]SC-NHEtOH exhibited binding affinities to both artificial prion aggregates as well as prion deposits in the brain. However, significant improvement in the binding affinity for PrP^Sc and blood-brain barrier permeability is necessary for the development of successful in vivo imaging probes for the detection of cerebral PrP^Sc in the brain.

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

Synthesis and Characterization of Radiogallium-Labeled Cationic Amphiphilic Peptides as Tumor Imaging Agents

SVS-1 is a cationic amphiphilic peptide (CAP) that exhibits a preferential cytotoxicity towards cancer cells over normal cells. In this study, we developed radiogallium-labeled SVS-1 (⁶⁷Ga-NOTA-KV6), as well as two SVS-1 derivatives, with the repeating KV residues replaced by RV or HV (⁶⁷Ga-NOTA-RV6 and ⁶⁷Ga-NOTA-HV6). All three peptides showed high accumulation in epidermoid carcinoma KB cells (53-143% uptake/mg protein). Though ⁶⁷Ga-NOTA-RV6 showed the highest uptake among the three CAPs, its uptake in 3T3-L1 fibroblasts was just as high, indicating a low selectivity. In contrast, the uptake of ⁶⁷Ga-NOTA-KV6 and ⁶⁷Ga-NOTA-HV6 into 3T3-L1 cells was significantly lower than that in KB cells. An endocytosis inhibition study suggested that the three ⁶⁷Ga-NOTA-CAPs follow distinct pathways for internalization. In the biodistribution study, the tumor uptakes were found to be 4.46%, 4.76%, and 3.18% injected dose/g of tissue (% ID/g) for ⁶⁷Ga-NOTA-KV6, ⁶⁷Ga-NOTA-RV6, and ⁶⁷Ga-NOTA-HV6, respectively, 30 min after administration. Though the radioactivity of these peptides in tumor tissue decreased gradually, ⁶⁷Ga-NOTA-KV6, ⁶⁷Ga-NOTA-RV6, and ⁶⁷Ga-NOTA-HV6 reached high tumor/blood ratios (7.7, 8.0, and 3.8, respectively) and tumor/muscle ratios (5.0, 3.3, and 4.0, respectively) 120 min after administration. ⁶⁷Ga-NOTA-HV6 showed a lower tumor uptake than the two other tracers, but it exhibited very low levels of uptake into peripheral organs. Overall, the replacement of lysine in SVS-1 with other basic amino acids significantly influenced its binding and internalization into cancer cells, as well as its in vivo pharmacokinetic profile. The high accessibility of these peptides to tumors and their ability to target the surface membranes of cancer cells make radiolabeled CAPs excellent candidates for use in tumor theranostics.

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

Feasibility studies of radioiodinated pyridyl benzofuran derivatives as potential SPECT imaging agents for prion deposits in the brain

INTRODUCTION

Prion diseases are fatal neurodegenerative disorders caused by the deposition of abnormal prion protein aggregates (PrP^Sc) in the central nervous system. This study aimed to evaluate the use of iodinated pyridyl benzofuran (IPBF) derivatives as single-photon emission computed tomography (SPECT) probes for the detection of cerebral PrP^Sc deposits.

METHODS

In vitro binding assays of IPBF derivatives were carried out in the recombinant mouse prion protein (rMoPrP) and brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. SPECT imaging of 5-(5-[¹²³I]iodobenzofuran-2-yl)-N-methylpyridin-2-amine ([¹²³I]IPBF-NHMe) was performed on mBSE-infected and mock-infected mice.

RESULTS

Fluorescence microscopy results showed that fluorescence signals of IPBF derivatives corresponded to the thioflavin-T positive amyloid deposits of PrP^Sc in the brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. Among the IPBF derivatives, 5-(5-iodobenzofuran-2-yl)-N-methylpyridin-2-amine (IPBF-NHMe) exhibited the highest binding affinity to the recombinant mouse prion protein (rMoPrP) aggregates with a K_i of 14.3 nM. SPECT/computed tomography (CT) imaging and ex vivo autoradiography demonstrated that the [¹²³I]IPBF-NHMe distribution in brain tissues of mBSE-infected mice co-localized with PrP^Sc deposits.

CONCLUSION

[¹²³I]IPBF-NHMe appears to be a prospective SPECT tracer for monitoring prion deposits in living brain tissues.

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.

Discovery of inner centromere protein-derived small peptides for cancer imaging and treatment targeting survivin

Survivin belongs to the inhibitor of apoptosis protein family, which is consistently overexpressed in most cancer cells but rarely expressed in normal adult tissues. Therefore, the detection and inhibition of survivin are regarded as attractive strategies for cancer‐specific treatment. In this study, we designed and synthesized 7‐19 residues of inner centromere protein (INCENP)‐derived small peptides (INC peptides) as novel survivin‐targeting agents. The INC peptides showed binding affinity for the human survivin protein (K_d = 91.4‐255 nmol L⁻¹); INC_16‐22, which contains residues 16‐22 of INCENP, showed the highest affinity (91.4 nmol L⁻¹). Confocal fluorescence imaging showed consistent colocalization of FITC‐INC_16‐22 and survivin in cell lines. Nona‐arginine‐linked INC_16‐22 (r9‐INC_16‐22) rendered INC_16‐22 cells penetrable and strongly inhibited cell growth of MIA PaCa‐2 cells (52% inhibition at 1.0 µmol L⁻¹) and MDA‐MB‐231 cells (60% inhibition at 10 µmol L⁻¹) as determined by MTT assays. The exposure of MIA PaCa‐2 cells to 40 µmol L⁻¹ r9‐INC_16‐22 apparently reduced the intracellular protein expression levels of survivin. However, cleaved caspase‐3 was significantly increased in cells treated with r9‐INC_16‐22, even at 10 µmol L⁻¹, compared to untreated cells. Flow cytometry revealed that r9‐INC_16‐22 strongly induced apoptosis in MIA PaCa‐2 cells. These results indicate that the cytotoxic effects of r9‐INC_16‐22 could be mediated mainly through the disruption of survivin‐dependent antiapoptotic functions and partly because of the direct degradation of the survivin protein. Our findings suggest that INC peptides can act as useful scaffolds for novel cancer imaging and anticancer agents.

Development of Radioiodinated Benzofuran Derivatives for in Vivo Imaging of Prion Deposits in the Brain

Prion diseases are fatal neurodegenerative disorders associated with the deposition of abnormal prion protein aggregates (PrP^Sc) in the brain tissue. Here, we report the development of ¹²⁵I-labeled iodobenzofuran (IBF) derivatives as single photon emission computed tomography (SPECT) imaging probes to detect cerebral PrP^Sc deposits. We synthesized and radioiodinated several 5-IBF and 6-IBF derivatives. The IBF derivatives were evaluated as prion imaging probes using recombinant mouse prion protein (rMoPrP) aggregates and brain sections of mouse-adapted bovine spongiform encephalopathy (mBSE)-infected mice. Although all the IBF derivatives were strongly adsorbed on the rMoPrP aggregates, [¹²⁵I]5-IBF-NHMe displayed the highest adsorption rate and potent binding affinity with an equilibrium dissociation constant (K_d) of 12.3 nM. Fluorescence imaging using IBF-NHMe showed clear signals of the PrP^Sc-positive amyloid deposits in the mBSE-infected mouse brains. Biodistribution studies in normal mice demonstrated slow uptake and clearance from the brain of ¹²⁵I-IBF derivatives. Among the derivatives, [¹²⁵I]6-IBF-NH₂ showed the highest peak brain uptake [2.59% injected dose (ID)/g at 10 min] and good clearance (0.51% ID/g at 180 min). Although the brain distribution of IBF derivatives should still be optimized for in vivo imaging, these compounds showed prospective binding properties to PrP^Sc. Further chemical modification of these IBF derivatives may contribute to the discovery of clinically applicable prion imaging probes.

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.

Synthesis and evaluation of radioactive/fluorescent peptide probes for imaging of legumain activity

Legumain or asparaginyl endopeptidase is an enzyme overexpressed in some cancers and involved in cancer migration, invasion, and metastasis. We have developed radioiodine- ([¹²⁵I]I-LCP) or fluorescein-labeled peptides (FL-LCP) with a cell-permeable d-Arg nonamer fused to an anionic d-Glu nonamer via a legumain-cleavable linker, to function as peptide probes that measure and monitor legumain activity. Non-cleavable probes of FL-NCP and [¹²⁵I]I-NCP were similarly prepared and evaluated as negative control probes by altering their non-cleavable sequence. Model peptides with the legumain-cleavable or non-cleavable sequence (LCP and NCP, respectively) reacted with recombinant human legumain, and only LCP was digested by this enzyme. [¹²⁵I]I-LCP uptake in legumain-positive HCT116 cells was significantly higher than that of [¹²⁵I]I-NCP (11.2 ± 0.44% vs 1.75 ± 0.06% dose/mg). The accumulation of FL-LCP in the HCT116 cells was rather low (4.75 ± 0.29% dose/mg protein), but not significantly different from the levels of FL-NCP. It is possible that low concentrations of [¹²⁵I]I-LCP (40 pM) can be effectively internalized after legumain cleavage. On the other hand, the cellular uptake of much higher concentrations of the FL-LCP derivative (1 mM) may be restricted by high concentrations of polyanions. The in vivo biodistribution studies in tumor-bearing mice demonstrated that the tumor uptake of [¹²⁵I]I-LCP was 1.34% injected dose per gram (% ID/g) at 30 min. The tumor/blood and tumor/muscle ratios at 30 min were 0.63 and 1.77, respectively, indicating that the [¹²⁵I]I-LCP accumulation in tumors was inadequate for in vivo imaging. Although further structural modifications are necessary to improve pharmacokinetic properties, [¹²⁵I]I-LCP has been demonstrated to be an effective scaffold for the development of nuclear medicine imaging probes to monitor legumain activity in living subjects.

Cardiac myoglobin participates in the metabolic pathway of selenium in rats

As an essential micronutrient, selenium deficiency is a leading cause of cardiovascular diseases. The heart is continuously beating to deliver blood to the entire body, and this requires a high amount of energy. An adult heart normally obtains 50-70% of its adenosine 5'-triphosphate from fatty acid β-oxidation. An increase in fatty acid oxidation activity induces the generation of larger amounts of by-products (reactive oxygen species, ROS) from mitochondrial oxidative phosphorylation. Selenium-dependent glutathione peroxidases play a critical role in the removal of these ROS, especially organic hydroperoxides, from the heart. The definitive transport and/or detailed metabolic pathways from the selenium-source compounds to the selenoproteins in the heart still remain unclear. We explored the selenium-binding proteins in a rat cardiac cell lysate using its reactive metabolic intermediate, selenotrisulfide (STS), and MALDI TOF-mass spectrometry. Several proteins with a free cysteine (Cys) thiol were found to be reactive with STS through a thiol-exchange reaction. The most distinctive Cys-containing protein in the cardiac cell lysate was identified as myoglobin (Mb) from a rat protein database search and tryptic fragmentation experiments. When separately examined in selenium adequate rats, selenium-binding to the cardiac Mb was verified using selenium-specific fluorometry. Cardiac Mb is thought to participate in the selenium metabolic pathway in the heart.

In vitro assessment of bioavailability of selenium from a processed Japanese anchovy, Niboshi

Niboshi is a commonly used foodstuff that is processed from Japanese anchovy (Engraulis japonicus) in Japanese cuisine. It was previously demonstrated that Niboshi and its water extract contained highly bioavailable selenium for selenium deficient mice. In this study, we assessed the selenium bioavailability from the extract of the Niboshi, using cultured cells. The activity of selenium-dependent glutathione peroxidase (GPx) of rat dorsal ganglion cells and human cervical carcinoma cells incubated with selenium from the Niboshi extract was over 2 times of that of the extract-free control cells and comparable to that of cells incubated with selenious acid of the same selenium concentration. These results suggest that selenium from the Niboshi extract was utilized for synthesis of the selenoprotein. Such in vitro selenium bioavailability was consistent with our previous results of in vivo assessment in mice.

Synthesis and characterization of 11 C-labeled benzyl amidine derivatives as PET radioligands for GluN2B subunit of the NMDA receptors

GluN2B-containing NMDA receptors (NMDARs) play fundamental roles in learning and memory, although they are also associated with various brain disorders. In this study, we synthesized and evaluated three ¹¹ C-labeled N-benzyl amidine derivatives 2-[¹¹ C]methoxybenzyl) cinnamamidine ([¹¹ C]CBA), N-(2-[¹¹ C]methoxybenzyl)-2-naphthamidine ([¹¹ C]NBA), and N-(2-[¹¹ C]methoxybenzyl)quinoline-3-carboxamidine ([¹¹ C]QBA) as PET radioligands for these receptors. The ¹¹ C-benzyl amidines were synthesized via conventional methylation of corresponding des-methyl precursors with [¹¹ C]CH₃ I. In vitro binding characteristics were examined in brain sagittal sections using various GluN2B modulators and off-target ligands. Further, in vivo brain distribution studies were performed in normal mice. The ¹¹ C-labeled benzyl amidines showed high-specific binding to the GluN2B subunit at in vitro. In particular, the quinoline derivative [¹¹ C]QBA had the best binding properties in terms of high-brain localization to GluN2B-rich regions and specificity to the GluN2B subunit. Conversely, these ¹¹ C-radioligands showed the brain distributions were inconsistent with GluN2B expression in biodistribution experiments. The majority of the radiolabeled compounds were identified as metabolized forms of which amido derivatives seemed to be the major species. Although these ¹¹ C-ligands had high-specific binding to the GluN2B subunit, significant improvement in metabolic stability is necessary for successful positron emission tomography (PET) imaging of the GluN2B subunit of NMDARs.

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.

Synthesis and characterization of radioiodinated 3-phenethyl-2-indolinone derivatives for SPECT imaging of survivin in tumors

Survivin, overexpressed in most cancers, is associated with poor prognosis and resistance to radiation therapy and chemotherapy. Herein, we report the synthesis of three 3-phenethyl-2-indolinone derivatives and their application as in vivo imaging agents for survivin. Of these, 3-(2-(benzo[d][1,3]dioxol-5-yl)-2-oxoethyl)-3-hydroxy-5- iodoindolin-2-one (IPI-1) showed the highest binding affinity (K_d = 68.3 nM) to recombinant human survivin, as determined by quartz crystal microbalance (QCM). In vitro studies demonstrated that the [¹²⁵I]IPI-1 binding in survivin-positive MDA-MB-231 cells was significantly higher than that in survivin-negative MCF-10A cells. In addition, uptake of [¹²⁵I]IPI-1 by MDA-MB-231 cells decreased in a dose-dependent manner in the presence of the high-affinity survivin ligand S12; this is indicative of specific binding of [¹²⁵I]IPI-1 to cellular survivin protein in vitro. Biodistribution studies in MDA-MB-231 tumor-bearing mice demonstrated the moderate uptake of [¹²⁵I]IPI-1 in the tumor tissue (1.37% ID/g) at 30 min that decreased to 0.32% ID/g at 180 min. Co-injection of S12 (2.5 mg/kg) slightly reduced tumor uptake and the tumor/muscle ratio of [¹²⁵I]IPI-1. Although further structural modifications are necessary to improve pharmacokinetic properties, our results indicate that PI derivatives may be useful as tumor-imaging probes targeting survivin.

Selenoprotein L-inspired nano-vesicular peroxidase mimics based on amphiphilic diselenides

In this study, we developed selenoprotein L-inspired nano-vesicular peroxidase mimics based on amphiphilic diselenides. Selenocystine (SeCyst) was used as the starting material for the synthesis of four liposomal membrane-compatible diselenide derivatives (R-Se-Se-R') with two hydrophobic tails and a polar part. The diselenide derivatives were successfully incorporated into the phosphatidylcholine (PC)-based nano-vesicular scaffold. The results of the particle diameter and zeta-potential measurements suggested that the functional diselenide moiety was placed around the outer surface, not in the hydrophobic interior, of the liposomal membrane structures. The GPx-like catalytic activity of the diselenide/PC liposomes was determined by the conventional NADPH method using glutathione as the reducing substrate. For three peroxide substrates, i.e., hydrogen peroxide, organic tert-butyl hydroperoxide and cummen hydroperoxide, the cationic property-possessing diselenide derivatives in the PC-based liposomes resulted in a higher catalytic activity in comparison to electrically neutral and anionic derivatives. Overall, the diselenide derivatives at the surface of a liposomal colloidal scaffold could exert a GPx-like catalytic activity in physiological aqueous media.

Characterization of Selenium Species in the Shijimi Clam

Selenium is an essential trace element for humans and animals. Fish and shellfish are known to be rich in selenium and suppose to be an effective selenium source. In this study, we characterized the selenium species in the Shijimi clam (Corbicula japonica), which is a typical clam eaten in Japan. The Shijimi clam contains a relatively high concentration of selenium (3.5 µg-selenium/g-dry Shijimi). Approximately 30% of the total selenium in the Shijimi clam meat was extractable with water, while selenium in the Shijimi clam was hardly extracted with ethanol, chloroform and hexane. Based on an ultrafiltration study, the molecular mass of the major selenium species in the Shijimi water-extract was estimated to be less than 5000. Because amphoteric selenium species were contained in the Shijimi water-extract, which was indicated by ion-exchange chromatographic separation, an ion-pair reagent was utilized to extract the ionic selenium species into an organic solvent. A matrix assisted laser desorption ionization (MALDI) time of flight (TOF)-mass spectrometric analysis revealed the selenium isotopic pattern involving one selenium atom in a molecule with the ⁸⁰Se molecular ion peak at m/z 534. This selenium species was mainly found in the visceral part of the Shijimi clam by imaging mass spectrometry.

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.

Development of a 68Ge/68Ga Generator System Using Polysaccharide Polymers and Its Application in PET Imaging of Tropical Infectious Diseases

Gallium-68 (⁶⁸Ga) is a positron emitter for clinical positron emission tomography (PET) applications that can be produced by a ⁶⁸Ge/⁶⁸Ga generator without cyclotron. However, commercially available ⁶⁸Ge/⁶⁸Ga generator systems require multiple steps for the preparation of ⁶⁸Ga radiopharmaceuticals and are sometimes plagued by metallic impurities in the ⁶⁸Ga eluent. We developed a ⁶⁸Ge/⁶⁸Ga generator system using polysaccharide-based adsorbents and direct application of the generator-eluted ⁶⁸Ga-citrate to PET imaging of tropical infectious diseases. N-Methylglucamine (MG) as a ⁶⁸Ge-adsorbing unit (Sepha-MGs) was introduced to a series of Sephadex G-10, G-15, G-25, G-50, and G-75. In the batch method, over 97% of the ⁶⁸Ge in the solution was adsorbed onto the Sepha-MG series within 15 min. In particular, ⁶⁸Ge was effectively adsorbed on the Sepha(15)-MG packed columns and 70-80% of the ⁶⁸Ga was eluted by 1 mL of 0.1 M trisodium citrate with low ⁶⁸Ge contamination (<0.001%). The chemical form of the generator-eluted ⁶⁸Ga solution was identified as ⁶⁸Ga-citrate. In PET studies, affected regions in mice infected with Leishmania and severe fever with thrombocytopenia syndrome virus were clearly visualized using the ⁶⁸Ga-citrate. Sepha-MGs are useful adsorbents for ⁶⁸Ge/⁶⁸Ga generator systems with high ⁶⁸Ga elution efficiency and minimal ⁶⁸Ge breakthrough. These results indicated that eluted ⁶⁸Ga-citrate can be directly used for PET imaging of infectious sites in mice. This novel generator system may be useful for straightforward PET imaging of infection in clinical practice.

Evaluation for Peritoneal Injury at an Early Stage Using Dual Macromolecular Markers

Long-term peritoneal dialysis (PD) frequently produces morphological and functional changes of the peritoneum, making continuation of PD difficult. Therefore, it is necessary to evaluate peritoneal injury at an early stage and develop appropriate therapies. The aims of the present study were to evaluate peritoneal injury at an early stage and assess a drug for prevention of peritoneal injury using our previously developed novel evaluation method. Peritoneal injury was induced in model animals by intraperitoneal injection of methylglyoxal (MGO) for 1 to 5 consecutive days or chlorhexidine digluconate (CG) for 1 to 14 consecutive days. Tetramethylrhodamine-dextran (RD)-10 and fluorescein isothiocyanate-dextran (FD)-2000 were then injected into the peritoneal cavity and recovered after 120 min to evaluate peritoneal injury. The ratio of the concentration of RD-10 to FD-2000 (RD-10/FD-2000 ratio) significantly decreased in animals that had been treated with MGO or CG for 1 d. Moreover, the RD-10/FD-2000 ratio significantly increased in CG- and thalidomide-treated animals. The RD-10/FD-2000 ratio can be used to evaluate peritoneal injury at an early stage and assess the drug efficacy of thalidomide for prevention of peritoneal injury. This study will contribute to the development of therapeutic treatments for peritoneal injury.