97 research outputs found

    Termination of Graphene Edges Created by Hydrogen and Deuterium Plasmas

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    Edge engineering is important for both fundamental research and applications as the device size decreases to nanometer scale. This is especially the case for graphene because a graphene edge shows totally different electronic properties depending on the atomic structure and the termination. It has recently been shown that an atomically precise zigzag edge can be obtained by etching graphene and graphite using hydrogen (H) plasma. However, edge termination had not been studied directly. In this study, termination of edges created by H-plasma is studied by high-resolution electron energy loss spectroscopy (HREELS) to show that the edge is sp2\mathrm{sp}^{2} bonded and the edge carbon atom is terminated by only one H atom. This suggests that an ideal zigzag edge, which is not only atomically precise but also sp2\mathrm{sp}^{2} bonding, can be obtained by H-plasma etching. Etching of the graphite surface with plasma of a different isotope, deuterium (D), is also studied by scanning tunneling microscopy (STM) to show that D-plasma anisotropically etches graphite less efficiently, although it can make defects more efficiently, than H-plasma.Comment: 8 pages, 5 figure

    APOBEC3B is preferentially expressed at the G2/M phase of cell cycle

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    APOBEC3B (A3B) is a cytosine deaminase that converts cytosine to uracil in single-stranded DNA. Cytosine-to-thymine and cytosine-to-guanine base substitution mutations in trinucleotide motifs (APOBEC mutational signatures) were found in various cancers including lymphoid hematological malignancies such as multiple myeloma and A3B has been shown to be an enzymatic source of mutations in those cancers. Although the importance of A3B is being increasingly recognized, it is unclear how A3B expression is regulated in cancer cells as well as normal cells. To answer these fundamental questions, we analyzed 1276 primary myeloma cells using single-cell RNA-sequencing (scRNA-seq) and found that A3B was preferentially expressed at the G2/M phase, in sharp contrast to the expression patterns of other APOBEC3 genes. Consistently, we demonstrated that A3B protein was preferentially expressed at the G2/M phase in myeloma cells by cell sorting. We also demonstrated that normal blood cells expressing A3B were also enriched in G2/M-phase cells by analyzing scRNA-seq data from 86, 493 normal bone marrow mononuclear cells. Furthermore, we revealed that A3B was expressed mainly in plasma cells, CD10+ B cells and erythroid cells, but not in granulocyte-macrophage progenitors. A3B expression profiling in normal blood cells may contribute to understanding the defense mechanism of A3B against viruses, and partially explain the bias of APOBEC mutational signatures in lymphoid but not myeloid malignancies. This study identified the cells and cellular phase in which A3B is highly expressed, which may help reveal the mechanisms behind carcinogenesis and cancer heterogeneity, as well as the biological functions of A3B in normal blood cells

    CAGE-Seq Reveals that HIV-1 Latent Infection Does Not Trigger Unique Cellular Responses in a Jurkat T Cell Model

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    The cure for HIV-1 is currently stalled by our inability to specifically identify and target latently infected cells. HIV-1 viral RNA/DNA or viral proteins are recognized by cellular mechanisms and induce interferon responses in virus-producing cells, but changes in latently infected cells remain unknown. HIVGKO contains a green fluorescent protein (GFP) reporter under the HIV-1 promoter and a monomeric Kusabira orange 2 (mKO2) reporter under the internal elongation factor alpha (EF1α) promoter. This viral construct enables direct identification of both productively and latently HIV-1-infected cells. In this study, we aim to identify specific cellular transcriptional responses triggered by HIV-1 entry and integration using cap analysis of gene expression (CAGE). We deep sequenced CAGE tags in non-infected and latently and productively infected cells and compared their differentially expressed transcription start site (TSS) profiles. Virus-producing cells had differentially expressed TSSs related to T-cell activation and apoptosis compared to those of non-infected cells or latently infected cells. Surprisingly, latently infected cells had only 33 differentially expressed TSSs compared to those of non-infected cells. Among these, SPP1 and APOE were downregulated in latently infected cells. SPP1 or APOE knockdown in Jurkat T cells increased susceptibility to HIVGKO infection, suggesting that they have antiviral properties. Components of the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway, MLST8, 4EBP, and RPS6, were significant TSSs in productively infected cells, and S6 kinase (S6K) phosphorylation was increased compared to that in latently infected cells, suggesting that mTOR pathway activity plays a role in establishing the latent reservoir. These findings indicate that HIV-1 entry and integration do not trigger unique transcriptional responses when infection becomes latent

    Identification of a novel arthritis-associated osteoclast precursor macrophage regulated by FoxM1

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    Osteoclasts have a unique bone-destroying capacity, playing key roles in steady-state bone remodeling and arthritic bone erosion. Whether the osteoclasts in these different tissue settings arise from the same precursor states of monocytoid cells is presently unknown. Here, we show that osteoclasts in pannus originate exclusively from circulating bone marrow-derived cells and not from locally resident macrophages. We identify murine CX3CR1hiLy6CintF4/80+I-A+/I-E+ macrophages (termed here arthritis-associated osteoclastogenic macrophages (AtoMs)) as the osteoclast precursor-containing population in the inflamed synovium, comprising a subset distinct from conventional osteoclast precursors in homeostatic bone remodeling. Tamoxifen-inducible Foxm1 deletion suppressed the capacity of AtoMs to differentiate into osteoclasts in vitro and in vivo. Furthermore, synovial samples from human patients with rheumatoid arthritis contained CX3CR1+HLA-DRhiCD11c+CD80−CD86+ cells that corresponded to mouse AtoMs, and human osteoclastogenesis was inhibited by the FoxM1 inhibitor thiostrepton, constituting a potential target for rheumatoid arthritis treatment.Hasegawa T., Kikuta J., Sudo T., et al. Identification of a novel arthritis-associated osteoclast precursor macrophage regulated by FoxM1. Nature Immunology 20, 1631 (2019); https://doi.org/10.1038/s41590-019-0526-7

    Thioredoxin-interacting protein suppresses bladder carcinogenesis.

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    Thioredoxin-interacting protein (TXNIP), which has a tumor-suppressive function, is underexpressed in some human cancers. The function of TXNIP in vivo in carcinogenesis is not fully understood. Here, we show TXNIP to be downregulated in human bladder cancer according to grade and stage and also that loss of TXNIP expression facilitates bladder carcinogenesis using a mouse bladder cancer model. N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced bladder cancer was found in 100% of Txnip knockout (KO) mice at week 8 of 0.025% BBN administration but in only 22% of wild-type (WT) mice at the same point. Among growth stimulators, phospho-extracellular signal-regulated kinase (pERK) expression was stronger during bladder carcinogenesis in Txnip-KO mice than in WT mice. We then evaluated TXNIP's effects on ERK activation through various growth stimulators and their receptors. Overexpression of TXNIP in human bladder cancer cells attenuated pERK expression upon stimulation with stromal cell-derived factor-1 (SDF-1) but not with epidermal growth factor or insulin-like growth factor-1. In Txnip-KO mice, immunohistochemical analysis showed enhanced expression of C-X-C chemokine receptor type 4 (CXCR4), the receptor of SDF-1, and of pERK in urothelial cells during BBN-induced bladder carcinogenesis. Finally, subcutaneous injection of CXCR4 antagonist, TF14016, attenuated pERK in urothelial cells and suppressed bladder carcinogenesis. These data indicate that TXNIP negatively regulates bladder carcinogenesis by attenuating SDF-1-CXCR4-induced ERK activation. This signal transduction pathway can be a potent target in preventing or treating bladder cancer

    身体活動量評価の特徴と有用性

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    総説Review articles 本論文の目的は,身体活動量の評価方法に関する知見を整理し,各評価方法の特徴および有用性について検討することであった.身体活動量の評価方法は,高い妥当性・信頼性が検証されている二重標識水法をgold standard として,現在までにエネルギー消費量測定法や加速度計法などの方法の検証が行われてきた.エネルギー消費量測定法は,二重標識水法と同様に高い妥当性・信頼性が得られる代わりに,整った設備や長時間の拘束を要するため,疫学調査やフィールド調査としては不向きであった.加速度計法は,対象者の負担が少なく,長期の測定が可能であり,妥当性・信頼性のあるデータの測定が可能であるが,著明な身体疾患を有する対象者や四肢末端の細部の動きに関しては測定が困難な場合も懸念された.身体活動量の評価方法を選択する場合には,対象者の年齢層や身体的特徴,あるいは身体活動量の評価の目的を考慮する必要があると考えられた. The purpose of this review article was to organize the knowledge on the evaluation methods of physical activity, and to examine the features and usefulness of each method. For the evaluation of physical activity, methods such as measurement of energy expenditure and use of the accelerometer have been verified to date, with the doubly labeled water method as the gold standard, which has been verified to have high validity and reliability. The measurement of energy expenditure is deemed unsuitable for epidemiological and field surveys because it requires well-equipped laboratories and long-term restraint in contrast to obtaining high validity and reliability measurements like the doubly labeled water method. The accelerometer method is less burdensome to the subject, enables long-term measurement, and allows measurement of data validity and reliability; however, there is concern that it may be difficult to measure the movement of the subject with remarkable physical disorder or the details of the extremities of the limbs. When choosing the evaluation method of physical activity, it seems necessary to consider the age group and physical characteristics of the subject, as well as the purpose of the evaluation

    Association Between PSCA Variants and Duodenal Ulcer Risk

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    Background: While duodenal ulcer (DU) and gastric cancer (GC) are both H. pylori infection-related diseases, individuals with DU are known to have lower risk for GC. Many epidemiological studies have identified the PSCA rs2294008 T-allele as a risk factor of GC, while others have found an association between the rs2294008 C-allele and risk of DU and gastric ulcer (GU). Following these initial reports, however, few studies have since validated these associations. Here, we aimed to validate the association between variations in PSCA and the risk of DU/GU and evaluate its interaction with environmental factors in a Japanese population. Methods: Six PSCA SNPs were genotyped in 584 DU cases, 925 GU cases, and 8,105 controls from the Japan Multi-Institutional Collaborative Cohort (J-MICC). Unconditional logistic regression models were applied to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between the SNPs and risk of DU/GU. Results: PSCA rs2294008 C-allele was associated with per allele OR of 1.34 (95% CI, 1.18–1.51; P = 2.28 × 10−6) for the risk of DU. This association was independent of age, sex, study site, smoking habit, drinking habit, and H. pylori status. On the other hand, we did not observe an association between the risk of GU and PSCA SNPs. Conclusions: Our study confirms an association between the PSCA rs2294008 C-allele and the risk of DU in a Japanese population

    High testosterone levels in prostate tissue obtained by needle biopsy correlate with poor-prognosis factors in prostate cancer patients

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    Background: There is currently no consensus on the correlations between androgen concentrations in prostate tissue and blood and stage and pathological grade of prostate cancer. In this study, we used a newly-developed ultra-sensitive liquid-chromatography tandem mass spectrometry method to measure testosterone (T) and dihydrotestosterone (DHT) concentrations in blood and needle biopsy prostate specimens from patients with prostate cancer.Methods: We analyzed androgen levels in 196 men diagnosed with prostate cancer. All patients had undergone systematic needle biopsy, and an additional needle biopsy from the peripheral zone was conducted for the simultaneous determination of T and DHT. We analyzed the relationships between T and DHT levels in tissue and blood and Gleason score, clinical stage, and percentage of positive biopsy cores, using multivariate analysis. Results: The median T and DHT levels in blood were 3551.0 pg/mL and 330.5 pg/mL, respectively. There was a strong correlation between serum T and DHT. The median T and DHT levels in prostate tissue were 0.5667 pg/mg and 7.0625 pg/mg, respectively. In multivariate analysis, serum prostate-specific antigen and tissue T levels were significantly associated with poor prognosis; high T levels in prostate tissue were significantly related to high Gleason score (p = 0.041), advanced clinical stage (p = 0.002), and a high percentage of positive biopsy cores (p = 0.001). Conclusions: The results of this study indicate that high T levels in prostate tissue are related to high Gleason score, advanced clinical stage, and a high percentage of positive biopsy cores in patients with prostate cancer. T level in needle biopsy specimens may therefore be a useful prognostic factor in prostate cancer patients
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