Evaluation of QSAR models for predicting mutagenicity: outcome of the Second Ames/QSAR international challenge project

Quantitative structure-activity relationship (QSAR) models are powerful in silico tools for predicting the mutagenicity of unstable compounds, impurities and metabolites that are difficult to examine using the Ames test. Ideally, Ames/QSAR models for regulatory use should demonstrate high sensitivity, low false-negative rate and wide coverage of chemical space. To promote superior model development, the Division of Genetics and Mutagenesis, National Institute of Health Sciences, Japan (DGM/NIHS), conducted the Second Ames/QSAR International Challenge Project (2020-2022) as a successor to the First Project (2014-2017), with 21 teams from 11 countries participating. The DGM/NIHS provided a curated training dataset of approximately 12,000 chemicals and a trial dataset of approximately 1,600 chemicals, and each participating team predicted the Ames mutagenicity of each trial chemical using various Ames/QSAR models. The DGM/NIHS then provided the Ames test results for trial chemicals to assist in model improvement. Although overall model performance on the Second Project was not superior to that on the First, models from the eight teams participating in both projects achieved higher sensitivity than models from teams participating in only the Second Project. Thus, these evaluations have facilitated the development of QSAR models.

A potent allele marker related to low bull conception rate in Japanese Black bulls

Over the years, there has been considerable variation in the bull conception rate (BCR) of Japanese Black cattle; moreover, several Japanese Black bulls with a low BCR of ≤10% have been identified. However, the alleles responsible for the low BCR are not determined yet. Therefore, in this study, we aimed to identify single-nucleotide polymorphisms (SNPs) for predicting low BCR. To this end, the genome of Japanese Black bulls was comprehensively examined by a genome-wide association study with whole-exome sequencing (WES), and the effect of the identified marker regions on BCR was determined. The WES analysis of six sub-fertile bulls with a BCR of ≤10% and 73 normal bulls with a BCR of ≥40% identified a homozygous genotype for low BCR in Bos taurus autosome 5 in the region between 116.2 and 117.9 Mb. The g.116408653G > A SNP in this region had the most significant effect on the BCR (P-value = 1.0 × 10^-23), and the GG (55.4 ± 11.2%) and AG (54.4 ± 9.4%) genotypes in the SNP had a higher phenotype than the AA (9.5 ± 6.1%) genotype for the BCR. The mixed model analysis revealed that g.116408653G > A was related to approximately 43% of the total genetic variance. In conclusion, the AA genotype of g.116408653G > A is a useful index for identifying sub-fertile Japanese Black bulls. Some positive and negative effects of SNP on the BCR were presumed to identify the causative mutations, which can help evaluate bull fertility.

Fine Particle Adsorption Capacity of Volcanic Soil from Southern Kyushu, Japan

"Akahoya" is a volcanic soil classified as a special soil deposited in Kyushu, Japan. Many of its properties are not yet clearly understood. We found that Akahoya had the potential to adsorb bacteria in cattle feces, which prompted us to investigate its material properties and perform experiments to comprehensively evaluate its adsorption performance for various fine particles such as acidic and basic dyes, NO_x/SO_x gas, and phosphoric acid ions, in addition to bacteria. Akahoya had a very high specific surface area owing to the large number of nanometer-sized pores in its structure; it exhibited a high adsorption capacity for both NO₂ and SO₂. Regarding the zeta potential of Akahoya, the point of zero charge was approximately pH 7.0. The surface potential had a significant effect on the adsorption of acidic and basic dyes. Akahoya had a very high cation exchange capacity when the sample surface was negatively charged and a high anion exchange capacity when the sample surface was positively charged. Akahoya also exhibited a relatively high adsorption capacity for phosphoric acid because of its high level of Al₂O₃, and the immersion liquid had a very high Al ion concentration. Finally, filtration tests were performed on Escherichia coli suspension using a column filled with Akahoya or another volcanic soil sample. The results confirmed that the Escherichia coli adhered on the Akahoya sample. The results of the Escherichia coli release test, after the filtration test, suggested that this adhesion to Akahoya could be phosphorus-mediated.

Post-Disaster Mental Health and Dietary Patterns among Older Survivors of an Earthquake and Tsunami

OBJECTIVES

Research suggests that cardiometabolic disease risks are elevated among survivors of natural disasters, possibly mediated by changes in diet. Using the Brief Dietary History Questionnaire, we examined (1) dietary patterns among older survivors of the 2011 Great East Japan Earthquake and Tsunami, and (2) the contribution of posttraumatic stress symptoms (PTSS)/depressive symptoms, as well as relocation to temporary housing on dietary patterns and (3) gender differences in the associations.

DESIGN, SETTING AND PARTICIPANTS

Data came from a prospective cohort study of 1,375 survivors aged 65-89 years (44.6% male).

MEASUREMENTS

PTSS/depression onset was evaluated in 2013, 2.5 years after the disaster. Dietary data was collected with a self-administered brief-type diet history questionnaire in 2020. A principal component analysis identified three posterior dietary patterns.

RESULTS

Diet 1 consisted of high intake of vegetables, soy products, and fruits; Diet 2 consisted of carbohydrate-rich foods and snacks/sweets; Diet 3 consisted of high intake of alcoholic beverages, meat, and seafood. Least-squares linear regression revealed that individuals with PTSS/depression were less likely to exhibit Diet 1, while individuals with PTSS were more likely to exhibit Diet 2 and 3. Especially, males who had depression showed an unhealthy dietary pattern. Those who have lived in a trailer-style temporary housing reported less consumption of Diet 3.

CONCLUSION

Survivors of disaster with symptoms of mental illness tended to exhibit less healthy dietary patterns after 9 years. Diet varied by type of post-disaster mental illness, gender, and current social circumstances. We lacked pre-disaster BDHQ data, which is a limitation.

Comprehensive Analyses of the Bacterial Population in Non-Healing Claw Lesions of Dairy Cattle

Non-healing claw lesions (NHCLs) are a newly characterized disorder affecting the deep dermis of the hoof in dairy cattle. Although NHCLs are thought to be associated with bovine digital dermatitis (BDD), their precise etiology is not yet understood. To investigate the bacterial populations present in each type of NHCL (toe necrosis: TN, non-healing white line disease: nhWLD, and a non-healing sole ulcer: nhSU), and the newly added entity non-healing verrucous-like lesions (nhVLL), 16S rRNA-based metagenomic analysis with next-generation sequencing (NGS) was employed. Twelve cases of NHCLs (3 TN, 3 nhWLD, 4 nhSU, and 2 nhVLL) were collected from five dairy farms in two prefectures in Japan. Three samples of healthy hoof dermis collected from two farms and a slaughterhouse were used as controls. Furthermore, culture-dependent and -independent approaches were conducted for detecting Treponema species and Fusobacterium necrophorum. As reported in BDD, Treponema species and F. necrophorum were detected frequently from NHCLs by PCR and immunohistochemistry, but NGS showed that these bacterial genera were not predominant in NHCLs. The predominant bacterial genera in NHCLs differed among the lesions examined, suggesting that Treponema species present predominantly in BDD were not predominant in NHCLs and that the bacterial population in NHCLs may vary among individual cattle and/or farms.

The prognostic value of 18F-FDG PET/CT taken immediately after completion of radiotherapy for lung cancer treated with concurrent chemoradiotherapy: A pilot study

PURPOSE

The prognostic value of F-18 fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) taken immediately after completion of radiotherapy in lung cancer patients is not well known. The purpose of this study is to assess the prognostic value of PET/CT taken immediately after completion of radiotherapy in lung cancer patients.

MATERIALS AND METHODS

Patients with primary lung cancer planned to undergo concurrent chemoradiotherapy were enrolled. Patients underwent PET/CT scans at 3 time points: before radiotherapy, within 24hours of completing radiotherapy (im-PET/CT), and 2-9 months after radiotherapy (post-PET/CT). Maximum standardized uptake value (SUV_max) was obtained. A post-PET/CT-SUV_max cut-off of 2.5 was determined as radiotherapy success.

RESULTS

Nineteen patients were enrolled. im-PET/CT-SUV_max for patients in the high post-PET/CT-SUV_max group was significantly higher than that of the low group (P=0.004). Receiver operator curve analysis indicated that im-PET/CT-SUV_max of 4.35 was an optimal cut-off value to discriminate between the two groups. Multivariable analysis showed that a high im-PET/CT-SUV_max was significantly associated with a high post-PET/CT-SUV_max (P=0.003).

CONCLUSION

PET/CT-SUV_max taken immediately following radiotherapy was associated with that evaluated 2-9 months after radiotherapy.

Determination of physiological cardiac myosin-binging protein levels (cMyc) in healthy populations

Background

Cardiac myosin–binding protein C (cMyC) is a cardiac-restricted protein that has more abundant, rapid release and clearance kinetics than cardiac troponin. The current ESC guideline suggests the cMyC may provide value as an alternative to cardiac troponin. The 99th percentile value is universally endorsed as the reference cut off to aid in the diagnosis of acute myocardial infarction (AMI), however, none of the report of healthy population of cMyC.

Purpose

The aim of this study was to evaluate the distribution of cMyC values in healthy subjects.

Methods

We used two cohorts in this retrospective study. 1) Healthy subjects; a total of 500 subjects (250 men and 250 women) who had annual health examinations in 2012 in the area of Kamigoto, a suburb of Nagasaki city in Southern Japan were enrolled. All participants showed none of abnormal findings including cell blood counts, chemical analysis, liver function tests, general urine tests, occult blood tests of stool, barium swallow, mammography for women, abdominal ultrasound sonography, and electrocardiogram. All blood samples were obtained in a fasting state in the morning. 2) Chest pain subjects; we collected samples from 250 subjects including 50 with non-ST elevation myocardial infarction visited admitted to a university hospital for measurement of high-sensitivity troponin T and coronary artery assessment by coronary angiography. We measured cMyC level in both cohorts by HISCL™-800 system (Sysmex corporation, Japan). The assay has a limit of detection of 0.5 ng/L and a lower limit of quantification of 1.3 ng/L.

Result

In healthy subjects, median age (IQR) was 44 (20, 82) in men and 50 (23, 91) in women. The 99th percentile of cMyC was 27.3 ng/L, which was around one-third lower than that in previous report (87 ng/L). In chest pain subjects, the concentrations of cMyC at presentation were significantly higher in those with versus without AMI (median, 66 ng/L versus 10 ng/L, P<0.001). Discriminatory power for AMI, as quantified by the area under the receiver-operating characteristic curve (AUC), was comparable for cMyC (AUC, 0.85 (95% CI 0.79–0.91) and hs-cTnT (AUC, 0.81 (95% CI 0.76–0.88)).

Conclusion

We defined the normal range of cMyC in healthy Japanese subjects. The level of cMyC at presentation provides discriminatory power comparable to hs-cTnT in the diagnosis of AMI. To determine the physiological value of a biomarker may be necessary to evaluate enough information about their health status.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research

Work-related increases in titer of Campylobacter jejuni antibody among workers at a chicken processing plant in Miyazaki prefecture, Japan, independent of individual ingestion of edible raw chicken meat

Workers in poultry abattoirs may be frequently exposed to Campylobacter jejuni, which is a leading cause of bacterial food poisoning in Japan. The present study was conducted to measure the titers of IgG and IgA antibodies against C. jejuni among 104 female workers in a chicken processing plant in Miyazaki prefecture, Japan. Information regarding habitual ingestion of raw chicken meat and potential occupational risk factors was collected using a questionnaire. Acid extracts of four C. jejuni strains representing the genotypes most dominant in Miyazaki were used as antigens. The levels of both immunoglobulins measured by ELISA were not correlated with ingestion of edible raw chicken meat, the amount consumed in one sitting, or its frequency. Although age was correlated with antibody levels, the length of employment was not. Furthermore, the IgG and IgA levels in workers at the evisceration step were significantly higher than those at other locations in the plant. To identify the bacterial proteins recognized by the workers' IgG and IgA antibodies, Western blotting followed by LC/MS was conducted. Flagellin was identified as the common protein recognized in the sera of workers for whom ELISA demonstrated both the highest and lowest antibody levels. We concluded that the titers of IgG and IgA against C. jejuni in workers at the processing plant had been increased by occupational exposure to Campylobacter, regardless of raw chicken meat ingestion.

Use of hyperbaric oxygen therapy for preventing delayed neurological sequelae in patients with carbon monoxide poisoning: A multicenter, prospective, observational study in Japan

BACKGROUND

The purpose of this study was to clarify the practical clinical treatment for acute carbon monoxide (CO) poisoning in Japan and to investigate the efficacy of hyperbaric oxygen (HBO2) therapy in preventing delayed neurological sequelae (DNS) in the acute phase of CO poisoning.

METHODS

We conducted a multicenter, prospective, observational study of acute CO poisoning in Japan. Patients with acute CO poisoning were enrolled and their treatment details were recorded. The primary endpoint was the onset of DNS within 2 months of CO exposure. Factors associated with DNS were assessed with logistic regression analysis.

RESULTS

A total of 311 patients from 57 institutions were registered and 255 were analyzed: 171 received HBO2 therapy (HBO2 group) and 84 did not (normobaric oxygen [NBO2] group). HBO2 therapy was performed zero, once, twice, or three times within the first 24 h in 1.8%, 55.9%, 30.9%, and 11.3% of the HBO2 group, respectively. The treatment pressure in the first HBO2 session was 2.8 ATA (47.9% of the HBO2 group), 2.0 ATA (41.8%), 2.5 ATA (7.9%), or another pressure (2.4%). The incidence of DNS was 13/171 (7.6%) in the HBO2 group and 3/84 (3.6%) in the NBO2 group (P = 0.212). The number of HBO2 sessions in the first 24 h was one of the factors associated with the incidence of DNS (odds ratio, 2.082; 95% confidence interval, 1.101-3.937; P = 0.024).

CONCLUSIONS

The practical clinical treatment for acute CO poisoning, including HBO2 therapy, varied among the institutions participating in Japan. HBO2 therapy with inconsistent protocols showed no advantage over NBO2 therapy in preventing DNS. Multiple HBO2 sessions was associated with the incidence of DNS.

Andreev reflection of fractional quantum Hall quasiparticles

Electron correlation in a quantum many-body state appears as peculiar scattering behaviour at its boundary, symbolic of which is Andreev reflection at a metal-superconductor interface. Despite being fundamental in nature, dictated by the charge conservation law, however, the process has had no analogues outside the realm of superconductivity so far. Here, we report the observation of an Andreev-like process originating from a topological quantum many-body effect instead of superconductivity. A narrow junction between fractional and integer quantum Hall states shows a two-terminal conductance exceeding that of the constituent fractional state. This remarkable behaviour, while theoretically predicted more than two decades ago but not detected to date, can be interpreted as Andreev reflection of fractionally charged quasiparticles. The observed fractional quantum Hall Andreev reflection provides a fundamental picture that captures microscopic charge dynamics at the boundaries of topological quantum many-body states.

The prevalence of psychological distress during pregnancy in Miyagi Prefecture for 3 years after the Great Eas t Japan Earthquake

Background

To examine changes in psychological distress prevalence among pregnant women in Miyagi Prefecture, which was directly affected by the Great East Japan Earthquake and tsunami, and compare it with the other, less damaged areas of Japan.

Methods

This study was conducted in conjunction with the Japan Environment and Children`s Study. We examined 76,152 pregnant women including 8270 in Miyagi Regional Center and 67,882 in 13 other regional centers from the all-birth fixed data of the Japan Environment and Children’s Study. We then compared the prevalence and risk of distress in women in Miyagi Regional Center and women in the 13 regional centers for 3 years after the disaster.

Results

Women in the Miyagi Regional Center suffered more psychological distress than those in the 13 regional centers: OR 1.38 (95% CI, 1.03–1.87) to 1.92 (95% CI, 1.42–2.60). Additionally, women in the inland area had a consistently higher prevalence of psychological distress compared to those from the 13 regional centers: OR 1.67 (95% CI, 1.18–2.38) to 2.19 (95% CI, 1.60–2.99).

Conclusions

The lack of pre-disaster data in the Japan Environment and Children’s Study made it impossible to compare the incidence of psychological distress before and after the March 2011 Great East Japan Earthquake. However, 3 years after the Great East Japan Earthquake, the prevalence of pregnant women with psychological distress did not improve in Miyagi Regional Center. Further, the prevalence of mental illness in inland areas was consistently higher than that in the 13 regional centers after the disaster.

A genome-wide association study reveals a quantitative trait locus for calf mortality on chromosome 9 in Japanese Black cattle

Calf mortality is a major problem affecting cattle production. To identify genetic variants associated with calf mortality in Japanese Black cattle, we evaluated calf mortality as a categorical trait using a threshold model and conducted a GWAS. We identified two SNPs between 32 549 297 and 32 606 924 bp on bovine chromosome 9 that were significantly associated with calf mortality from 61 to 180 days after birth. The SNP showing the highest association was localized at a region 624 bp downstream of exon 4 of the anti-silencing function 1A histone chaperone gene (ASF1A) that promotes DNA damage repair, and the null mice, which exhibit pre- and postnatal lethality. This association was also detected using the breeding value of 334 sires. The frequency of the risk allele in Japanese Black cattle from locations across Japan was 0.013; although the frequency of ASF1A risk allele was low, it is widespread in the Japanese Black cattle population. Thus, it may be necessary to routinely monitor the cattle population for the presence of this allele.

A Single Arm Prospective Pilot Study Examining the Efficacy and Safety of Bevacizumab Single Maintenance Therapy Following Platinum-Based Chemotherapy in Patients with Advanced or Recurrent Cervical Cancer

Although the addition of bevacizumab to platinum-based combination chemotherapy has been recommended as a standard regimen for patients with advanced or recurrent cervical cancer, there is no clear evidence regarding the effectiveness of bevacizumab monotherapy as salvage chemotherapy. This study prospectively examined the efficacy and safety of switching from platinum-based chemotherapy combined with bevacizumab to single maintenance therapy in patients with advanced or recurrent cervical cancer. Patients were first treated with standard combination chemotherapy. However, if chemotherapy was discontinued because of an adverse event, bevacizumab monotherapy was continued for patients who agreed to participate in this study and provided written informed consent. The study protocol was approved by the Independent Review Board of Tohoku University School of Medicine (reception number 2017-1-540). A total of 15 patients (median age of 55 years, range 33-69 years) participated in this study. The median number of cycles of bevacizumab single maintenance administration was 8, and the main reasons for discontinuation were disease progression and adverse events. Bevacizumab single maintenance therapy had a disease control rate of 53.3% (CR 40%, PR 6.7%, SD 6.7%). The most frequent grade 3/4 clinical adverse events were proteinuria (5/15) and hypertension (4/15). No treatment-related deaths occurred. Bevacizumab single maintenance therapy was effective as salvage chemotherapy in patients with advanced or recurrent cervical cancer, and the safety profile was generally consistent with those reported in previous studies of bevacizumab monotherapy.

Associations between glycosylated hemoglobin level at less than 24 weeks of gestation and adverse pregnancy outcomes in Japan: The Japan Environment and Children's Study (JECS)

AIMS

To investigate the associations between glycosylated hemoglobin (HbA1c) levels at less than 24 weeks of gestation and adverse pregnancy outcomes in Japan.

METHODS

This was a prospective nationwide birth cohort study of 77,526 subjects with an HbA1c level of <6.5% (<48 mmol/mol) at less than 24 weeks of gestation. Associations of HbA1c level with adverse pregnancy outcomes were evaluated using multivariate analyses.

RESULTS

The adjusted odds ratios per 1% (11 mmol/mol) increase in HbA1c level were 1.77 (95% confidence interval [CI]: 1.48-2.12) for hypertensive disorders of pregnancy; 1.78 (95% CI: 1.12-2.83) for placental abruption; 1.30 (95% CI: 1.12-1.50) for preterm birth; 2.11 (95% CI: 1.41-3.16) for very preterm birth; 1.49 (95% CI: 1.33-1.68) for low birth weight infants; 1.95 (95% CI: 1.42-2.70) for macrosomia; 1.23 (95% CI: 1.09-1.39) for small for gestational age; 1.15 (95% CI: 1.04-1.28) for large for gestational age; and 1.29 (95% CI: 1.20-1.39) for the composite adverse pregnancy outcome.

CONCLUSIONS

The higher the HbA1c level, the higher the risk of adverse pregnancy outcomes in Japan. Further studies will be needed to determine prenatal management based on the HbA1c level in pregnant women with HbA1c <6.5% (<48 mmol/mol) at less than 24 weeks of gestation.

A highly multiplexed melt-curve assay for detecting the most prevalent carbapenemase, ESBL, and AmpC genes

Resistance to third-generation cephalosporins and carbapenems in Gram-negative bacteria is chiefly mediated by beta-lactamases including extended-spectrum beta-lactamase (ESBL), AmpC, and carbapenemase enzymes. Routine phenotypic detection methods do not provide timely results, and there is a lack of comprehensive molecular panels covering all important markers. An ESBL/carbapenemase high-resolution melt analysis (HRM) assay (SHV, TEM, CTX-M ESBL families, and NDM, IMP, KPC, VIM and OXA-48-like carbapenemases) and an AmpC HRM assay (16S rDNA control, FOX, MOX, ACC, EBC, CIT, and DHA) were designed and evaluated on 111 Gram-negative isolates with mixed resistance patterns. The sensitivity for carbapenemase, ESBL, and AmpC genes was 96.7% (95% confidence interval [CI]: 82.8-99.9%), 93.6% (95% CI: 85.7-97.9%), and 93.8% (95% CI: 82.8-98.7%), respectively, with a specificity of 100% (95% CI: 95.6-100%), 93.9% (95% CI: 79.8-99.3%), and 93.7% (95% CI: 84.5-98.2%). The HRM assays enable the simultaneous detection of the 14 most important ESBL, carbapenemase, and AmpC genes and could be used as a molecular surveillance tool or to hasten detection of antimicrobial resistance for treatment management.

A high-power, high-repetition-rate THz source for pump-probe experiments at Linac Coherent Light Source II

Experiments using a THz pump and an X-ray probe at an X-ray free-electron laser (XFEL) facility like the Linac Coherent Light Source II (LCLS II) require frequency-tunable (3 to 20 THz), narrow bandwidth (∼10%), carrier-envelope-phase-stable THz pulses that produce high fields (>1 MV cm^-1) at the repetition rate of the X-rays and are well synchronized with them. In this paper, a two-bunch scheme to generate THz radiation at LCLS II is studied: the first bunch produces THz radiation in an electromagnet wiggler immediately following the LCLS II undulator that produces X-rays from the second bunch. The initial time delay between the two bunches is optimized to compensate for the path difference in THz transport. The two-bunch beam dynamics, the THz wiggler and radiation are described, as well as the transport system bringing the THz pulses from the wiggler to the experimental hall.

Genome Sequencing Verifies Relapsed Infection of Helicobacter cinaedi

Background

Recurrent infections of Helicobacter cinaedi are often reported, and long-term antimicrobial treatment is empirically recommended to prevent such infections. However, there have been no studies examining whether recurrent infections are relapses of former infections or reinfections with different clones.

Methods

A 69-year-old woman presented with recurrent H cinaedi bacteremia-associated cellulitis after a 51-day interval. We isolated 10 colonies from the blood cultures obtained during each of the 2 episodes and subjected them to whole-genome sequencing (WGS). High-confidence single-nucleotide polymorphisms (SNPs) were identified by an assembly based method. Heterogeneous SNP sites were identified by read mapping. The susceptibility of a representative isolate to 14 antimicrobials was also examined.

Results

Whole-genome sequence analysis revealed only 6 SNP sites among the 20 isolates at the whole-genome level. Based on the 6 SNPs, 5 within-host variants (referred to as genotypes) were identified. All 5 genotypes were detected in the first infection; however, only 2 genotypes were detected in the second infection. Although the H cinaedi clone showed a higher minimum inhibitory concentration to fluoroquinolones and macrolides and responsible mutations were identified, none of the 6 SNPs appeared related to additional resistance.

Conclusions

The second infection analyzed here was a relapse of the first infection. A certain level of within-host genomic heterogeneity of the H cinaedi clone was already present in the first infection. Our results suggest the importance of longer treatment courses to eradicate H cinaedi for preventing the relapse of its infection.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

Search for CP Violation in Neutrino and Antineutrino Oscillations by the T2K Experiment with 2.2×10^{21} Protons on Target

The T2K experiment measures muon neutrino disappearance and electron neutrino appearance in accelerator-produced neutrino and antineutrino beams. With an exposure of 14.7(7.6)×10^{20} protons on target in the neutrino (antineutrino) mode, 89 ν_{e} candidates and seven anti-ν_{e} candidates are observed, while 67.5 and 9.0 are expected for δ_{CP}=0 and normal mass ordering. The obtained 2σ confidence interval for the CP-violating phase, δ_{CP}, does not include the CP-conserving cases (δ_{CP}=0, π). The best-fit values of other parameters are sin^{2}θ_{23}=0.526_{-0.036}^{+0.032} and Δm_{32}^{2}=2.463_{-0.070}^{+0.071}×10^{-3}  eV^{2}/c^{4}.

Toxicity of Heparinoids, with Special Reference to the Precipitation of Fibrinogen

To demonstrate whether the intravascular precipitation of fibrinogen is responsible for the toxicity of heparinoid, the relation between the toxicity of heparinoid in vivo and the precipitation of fibrinogen in vitro was investigated, using dextran sulfate of various molecular weights and various heparinoids.

1. There are close relationships between the molecular weight of dextran sulfate, its toxicity, and the quantity of fibrinogen precipitated.

2. The close relationship between the toxicity and the precipitation of fibrinogen found for dextran sulfate holds good for other heparinoids regardless of their molecular structures.

3. Histological findings suggest strongly that the pathological changes produced with dextran sulfate are caused primarily by the intravascular precipitates with occlusion of the capillaries.

From these facts, it is concluded that the precipitates of fibrinogen with heparinoid may be the cause or at least the major cause of the toxicity of heparinoid.

4. The most suitable molecular weight of dextran sulfate for clinical use was found to be 5,300 ~ 6,700, from the maximum value of the product (LD50 · Anticoagulant activity). This product (LD50 · Anticoagulant activity) can be employed generally to assess the comparative merits of various heparinoids.

5. Clinical use of the dextran sulfate prepared on this basis gave satisfactory results. No severe reaction was observed. However, two delayed reactions, alopecia and thrombocytopenia, were observed. These two reactions seem to come from the cause other than intravascular precipitation.

Abstract P4-03-12: Effects of PI3K inhibitors on endocrine-resistant cell lines and differences in the characteristics of ER positive breast cancer cells after acquired resistance to the inhibitors

Background

Mutations in phosphatidylinositol 3-kinase (PI3K), which encodes the catalytic subunit of PI3Kα, is one of the most frequent genomic alterations and is found in about 40% of estrogen receptor (ER)-positive, HER2 negative breast cancers. PIK3CA mutations promote the growth and proliferation of cancers via activation of the PI3K/mammalian target of rapamycin pathway and can mediate resistance to endocrine therapies in breast cancer. Although several clinical trials for PI3K inhibitors (PI3Kis) in ER-positive metastatic breast cancers are ongoing, the effects of PI3Kis on endocrine-resistant breast cancers with various characteristics and definitive biomarkers of PI3Kis are unclear. Using endocrine-resistant cells established in our laboratory, we evaluated the efficacy of PI3Ki in these cell lines and identified the characteristics associated with acquired resistance to PI3Kis in endocrine-resistant cells.

Results

Long-term estrogen deprivation-resistant (EDR) cell lines and fulvestrant-resistant cell lines (MFR and TFR) were established from MCF-7 and T-47D cells in our previous studies. These cell lines showed different ER expression levels, including high expression (EDR-1), low expression (EDR-2, -3), or no expression (MFR, TFR); all of these cell lines had the same PIK3CA mutations as the parental cell lines. The pan-class1 PI3Ki buparlisib (BKM120) and α-specific PI3K inhibitor alpelisib (BYL719) inhibited the proliferation of endocrine-resistant cell lines when compared with their parental cells. Among endocrine-resistant cells, MFR cells were dramatically inhibited by PI3Kis. Colony formation assays indicated that MFR cells were more sensitive to PI3Kis than other cells lines. Next, we established PI3Ki- and everolimus-resistant cell lines from EDR-1, EDR-2, and MFR cells using BKM120, BYL719, and everolimus. Analysis of the time required to generate resistant cells showed that MFR cells required twice as long to acquire resistance compared with EDR cells. Furthermore, the time required to acquire resistance to BYL719 was shorter than that for BKM120. BYL719-resistant (BYL-R) cells were effectively inhibited by BKM120 to a degree similar to that of parental cells; however, BYL-R cells lost sensitivity to BYL719 and everolimus. Evelolimus-resistant (EVE-R) cells were also the same. In contrast, BKM120-resistant (BKM-R) cells showed less sensitivity to BKM120, BYL719, and everolimus. In other words, the pan-PI3Ki BKM120 was able to inhibit the growth of BYL-R and EVE-R cells, whereas BYL719 and everolimus were not able to inhibit BKM-R cells sufficiently. In addition, there were no changes in ER expression in EDR-1, EDR-2, and MFR cells exposed to PI3Kis for 1 h. Interestingly, ER expression on EDR-2 cells with acquired resistance to PI3Kis was increased compared with that in parental cells.

Conclusion

Our findings showed that PI3Kis exhibited remarkable efficacy in all types of EDR cells, particularly in fulvestrant-resistant cell lines. In PI3Ki- and everolimus-resistant cell lines, BKM120 and BYL719 showed different effects, and BYL719 and everolimus may exhibit cross-resistance. Furthermore, PI3Kis were likely to change the expression of ER.

Citation Format: Tokuda E, Komatsu T, Sasaki S, Tsuboi K, Nakamura M, Iida M, Niwa T, Saito M, Hayashi S-I. Effects of PI3K inhibitors on endocrine-resistant cell lines and differences in the characteristics of ER positive breast cancer cells after acquired resistance to the inhibitors [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-03-12.

Evaluation of absolute measurement using a 4π plastic scintillator for the 4πβ-γ coincidence counting method

Absolute measurement by the 4πβ-γ coincidence counting method was conducted by two photomultipliers facing across a plastic scintillator to be focused on β ray counting efficiency. The detector was held with a through-hole-type NaI(Tl) detector. The results include absolutely determined activity and its uncertainty especially about extrapolation. A comparison between the obtained and known activities showed agreement within their uncertainties.

Crystallization and vitrification of electrons in a glass-forming charge liquid

Charge ordering (CO) is a phenomenon in which electrons in solids crystallize into a periodic pattern of charge-rich and charge-poor sites owing to strong electron correlations. This usually results in long-range order. In geometrically frustrated systems, however, a glassy electronic state without long-range CO has been observed. We found that a charge-ordered organic material with an isosceles triangular lattice shows charge dynamics associated with crystallization and vitrification of electrons, which can be understood in the context of an energy landscape arising from the degeneracy of various CO patterns. The dynamics suggest that the same nucleation and growth processes that characterize conventional glass-forming liquids guide the crystallization of electrons. These similarities may provide insight into our understanding of the liquid-glass transition.