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Latest Paper:
Tsuguto Fujimoto,
Masami Konagaya,
Miki Enomoto,
Kunio Tsuboi,
Kazuhiro Hashimoto,
Kiyosu Taniguchi,
Takashi Kodama,
Nobuhiko Okabe
National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
PCR, including real-time PCR, usually requires at least 1 h to obtain results. To shorten this time, a novel real-time PCR method (Hyper-PCR) was developed. This method utilizes high-speed DNA polymerase and a thin disc-type reaction vessel that can quickly alter the temperature of the reaction mixture in a newly developed PCR machine. Reactions capable of amplifying adenovirus (Ad) DNA can be completed within 11 min (3 temperature steps, 55 cycles). Hyper-PCR can detect 3.1-18.0 DNA copies/reaction of Ad types 1-4, 7, 8, 11, 15, 19, and 37. Hyper-PCR and conventional real-time PCR were applied to diagnose 147 clinical samples, and the results were compared. Hyper-PCR had a sensitivity of 100%(73/73) and a specificity of 100%(74/74), using conventional real-time PCR as the gold standard. Our newly developed PCR method, Hyper-PCR, was able to diagnose Ad infection within 17 min (not including the time for genome extraction). The thermocycling time of the novel PCR is faster than that of previously available PCR applications, and this method is thought to be potentially applicable to clinical and environmental diagnostics, where rapid diagnosis is important.
University of Tokyo.
The hepatitis C virus NS5B RNA dependent RNA polymerase (RdRp) is a key enzyme involved in viral replication. Interaction between NS5B RdRp and the viral RNA sequence is likely to be an important step in viral RNA replication. The C-terminal half of the NS5B coding sequence, which contains the important cis-acting replication element, has been identified as an NS5B binding sequence. In the present study, we confirm the specific binding of NS5B to one of the RNA stem-loop structures in the region, 5BSL3.2. In addition, we show that NS5B binds to the complementary strand of 5BSL3.2 (5BSL3.2N). The bulge structure of 5BSL3.2N was shown to be indispensable for tight binding to NS5B. In vitro RdRp activity was inhibited by 5BSL3.2N, indicating the importance of the RNA element in the polymerization by the RdRp. These results suggest the involvement of the RNA stem-loop structure of the negative-strand in the replication process.
Division of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan.
Keywords:
Kenichi Takemura,
Naomi Sakashita,
Yukio Fujiwara,
Yoshihiro Komohara,
Xiaofeng Lei,
Koji Ohnishi,
Hiroshi Suzuki,
Tatsuhiko Kodama,
Hiroshi Mizuta,
Motohiro Takeya
Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan; Department of Orthopaedic and Neuro-Musculoskeletal Surgery, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Osteoclasts originate from bone marrow monocyte/macrophage lineage cells, and their differentiation depends on macrophage colony-stimulating factor (M-CSF) and receptor activator nuclear factor kappa B (RANK) ligand. Class A scavenger receptor (SR-A) is one of the principal functional molecules of macrophages, and its level of expression declines during osteoclast differentiation. To investigate the role of SR-A in osteoclastogenesis, we examined pathological changes in femoral bone and the expression levels of osteoclastogenesis-related molecules in SR-A(-/-) mice. The femoral osseous density of SR-A(-/-) mice was higher than that of SR-A(+/+) mice, and the number of multinucleated osteoclasts was significantly decreased. An in vitro differentiation assay revealed that the differentiation of multinucleated osteoclasts from bone marrow-derived progenitor cells is impaired in SR-A(-/-) mice. Elimination of SR-A did not alter the expression level of the M-CSF receptor, c-fms; however, the expression levels of RANK and RANK-related osteoclast-differentiation molecules such as nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) and microphthalmia-associated transcription factor (MITF) significantly decreased. Furthermore, acetylated low-density lipoprotein (AcLDL), an SR-A ligand, significantly increased the expression level of RANK and MITF during osteoclast differentiation. These data indicate that SR-A promotes osteoclastogenesis via augmentation of the expression level of RANK and its related molecules.
Masaki Kawahara,
Atushi Takada,
Akihiko Tachibana,
Takashi Kodama,
Hiroaki Kobayashi,
Youko Takino,
Takeo Sugishita,
Yasuo Oono,
Teruaki Oka
Division of Surgery, Kanto Central Hospital, 6-25-1 Kamiyouga, Setagaya-ku, Tokyo, 158-8531, Japan, mkawahara-ths@umin.ac.jp.
A case of combined germ cell tumor and adenocarcinoma that arose in the colon of a 62-year-old man is described. The clinical and pathological findings are presented. The patient had widespread metastases at diagnosis and poor prognosis after operation (right hemicolectomy) was performed in spite of receiving chemotherapy. Pathologically, the germ cell tumor was composed of a yolk sac tumor and choriocarcinoma. Further, all the metastatic lesions showed a germ cell phenotype. An extragonadal germ cell tumor is extremely rare. To our knowledge, only a few cases have been reported in the English-language literature. Our present report will contribute to the understanding of the characteristics of this rare neoplasm.
The Research Center for Advanced Science and Technology, the University of Tokyo, Japan;
Endothelial cell activation and dysfunction underlie many vascular disorders including atherosclerosis, tumor growth and sepsis. Endothelial cell activation, in turn, is mediated primarily at the level of gene transcription. Here, we show that in response to a number of activation agonists, including vascular endothelial growth factor (VEGF), tumor necrosis factor (TNF)-alpha, and thrombin, endothelial cells demonstrate rapid and profound induction of the early growth response genes, Egr-1 and Egr-3. In VEGF-treated endothelial cells, induction of Egr-3 was far greater and more prolonged compared with Egr-1. VEGF-mediated stimulation of Egr-3 involved the inducible binding of NFATc, serum response factor (SRF) and CREB to their respective consensus motifs in the upstream promoter region of Egr-3. Knockdown of Egr-3 markedly impaired VEGF-mediated proliferation, migration, and tube formation of endothelial cells, and blocked VEGF-induced monocyte adhesion. Egr-3 knockdown abrogated VEGF-mediated vascular outgrowth from ex vivo aortic rings, and attenuated Matrigel plug vascularization and melanoma tumor growth in vivo. Together, these findings suggest that Egr-3 is a critical determinant of VEGF signaling in activated endothelial cells. Thus, Egr-3 represents a potential therapeutic target in VEGF-mediated vasculopathic diseases.
Kazumichi M Nishida,
Tomoko N Okada,
Takeshi Kawamura,
Toutai Mituyama,
Yoshinori Kawamura,
Sachi Inagaki,
Haidong Huang,
Dahua Chen,
Tatsuhiko Kodama,
Haruhiko Siomi,
Mikiko C Siomi
[1] Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan [2] Institute of Health Biosciences, University of Tokushima, Tokushima, Japan.
In Drosophila, the PIWI proteins, Aubergine (Aub), AGO3, and Piwi are expressed in germlines and function in silencing transposons by associating with PIWI-interacting RNAs (piRNAs). Recent studies show that PIWI proteins contain symmetric dimethyl-arginines (sDMAs) and that dPRMT5/Capsuleen/DART5 is the modifying enzyme. Here, we show that Tudor (Tud), one of Tud domain-containing proteins, associates with Aub and AGO3, specifically through their sDMA modifications and that these three proteins form heteromeric complexes. piRNA precursor-like molecules are detected in these complexes. The expression levels of Aub and AGO3, along with their degree of sDMA modification, were not changed by tud mutations. However, the population of transposon-derived piRNAs associated with Aub and AGO3 was altered by tud mutations, whereas the total amounts of small RNAs on Aub and AGO3 was increased. Loss of dprmt5 did not change the stability of Aub, but impaired its association with Tud and lowered piRNA association with Aub. Thus, in germline cells, piRNAs are quality-controlled by dPRMT5 that modifies PIWI proteins, in tight association with Tud.
Tomonari Sano,
Takeshi Kondo,
Hideyuki Matsutani,
Hitomi Morita,
Takehiro Arai,
Takako Sekine,
Shinichi Takase,
Akitsugu Oida,
Hiroshi Fukazawa,
Takahide Kodama,
Makoto Kondo,
Tadaaki Orihara,
Norikazu Yamada,
Jagat Narula
Department of Radiological Technology, Takase Clinic, Takasaki, 370-0036, Japan.
BACKGROUND: Since image quality obtained in the mid-diastolic [or slow filling (SF)] phase is generally superior to end-systolic image in coronary multidetector row computed tomography (MDCT), low heart rate (HR) comprises the most important factor for acquisition of high-quality images. However, despite HR <70 and optimum breath-hold, sometimes high quality images cannot be obtained in SF. We assessed the significance of PQ interval in acquisition of coronary MDCT. METHODS AND RESULTS: Of 541 consecutive patients who underwent coronary MDCT, 7 patients with incomplete breath-hold, 62 HR >/=70, and 70 arrhythmias were excluded. The remaining 402 patients (M: 222, 66+/-11 years), including 38 with first-degree atrioventricular block (1 degrees AVB, PQ >200ms) were evaluated. RR and PQ were measured on electrocardiogram and systolic and SF phase with 4-chamber cine cardiac computed tomography. SF significantly (p<0.0001) correlated with RR (SF=-471+0.720RR, r=0.887) in all subjects. The SF of without 1 degrees AVB (292+/-97ms) was significantly (p<0.0147) longer than that of with 1 degrees AVB (251+/-121ms), although RR was not significantly different between the two groups. The SF/RR of without 1 degrees AVB (27.2+/-6.1%) was also significantly (p<0.0001) higher than that of with 1 degrees AVB (22.7+/-8.0%). The coefficient of correlation between (RR-PQ) and SF [r=0.915, p<0.0001, SF=-362+0.742(RR-PQ)] was significantly (p<0.034) higher than that of correlation between RR and SF in all subjects. The SF of rank A image quality was significantly longer than that of rank B (p<0.0001) or rank C (p=0.0042). In critical HR (60-69bpm), the optimum phase was ES in 7/139 patients without 1 degrees AVB, and SF in 3/13 patients with 1 degrees AVB (chi(2), p<0.0416). CONCLUSION: Since SF depends on (RR-PQ), if PQ is long in critical HR, it might be difficult to reconstruct high quality images in the SF phase.
Hideyuki Yanai,
Tatsuma Ban,
ZhiChao Wang,
Myoung Kwon Choi,
Takeshi Kawamura,
Hideo Negishi,
Makoto Nakasato,
Yan Lu,
Sho Hangai,
Ryuji Koshiba,
David Savitsky,
Lorenza Ronfani,
Shizuo Akira,
Marco E Bianchi,
Kenya Honda,
Tomohiko Tamura,
Tatsuhiko Kodama,
Tadatsugu Taniguchi
Department of Immunology, Graduate School of Medicine and Faculty of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan.
The activation of innate immune responses by nucleic acids is crucial to protective and pathological immunities and is mediated by the transmembrane Toll-like receptors (TLRs) and cytosolic receptors. However, it remains unknown whether a mechanism exists that integrates these nucleic-acid-sensing systems. Here we show that high-mobility group box (HMGB) proteins 1, 2 and 3 function as universal sentinels for nucleic acids. HMGBs bind to all immunogenic nucleic acids examined with a correlation between affinity and immunogenic potential. Hmgb1(-/-) and Hmgb2(-/-) mouse cells are defective in type-I interferon and inflammatory cytokine induction by DNA or RNA targeted to activate the cytosolic nucleic-acid-sensing receptors; cells in which the expression of all three HMGBs is suppressed show a more profound defect, accompanied by impaired activation of the transcription factors interferon regulatory factor 3 (IRF3) and nuclear factor (NF)-kappaB. The absence of HMGBs also severely impairs the activation of TLR3, TLR7 and TLR9 by their cognate nucleic acids. Our results therefore indicate a hierarchy in the nucleic-acid-mediated activation of immune responses, wherein the selective activation of nucleic-acid-sensing receptors is contingent on the more promiscuous sensing of nucleic acids by HMGBs. These findings may have implications for understanding the evolution of the innate immune system and for the treatment of immunological disorders.
Hayato Hikita,
Tetsuo Takehara,
Takahiro Kodama,
Satoshi Shimizu,
Atsushi Hosui,
Takuya Miyagi,
Tomohide Tatsumi,
Hisashi Ishida,
Kazuyoshi Ohkawa,
Wei Li,
Tatsuya Kanto,
Naoki Hiramatsu,
Lothar Hennighausen,
Xiao-Ming Yin,
Norio Hayashi
Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan.
Bcl-2 homology domain 3 (BH3)-only protein Bid is posttranslationally cleaved by caspase-8 into its truncated form (tBid) and couples with stress signals to the mitochondrial cell death pathway. However, the physiological relevance of Bid is not clearly understood. Hepatocyte-specific knockout (KO) of Bcl-xL leads to naturally-occurring apoptosis despite co-expression of Mcl-1, which shares a similar anti-apoptotic function. We generated Bcl-xL KO, Bcl-xL/Bid double KO, Bcl-xL/Bak double KO, Bcl-xL/Bax double KO, and Bcl-xL/Bak/Bax triple KO mice and found that hepatocyte apoptosis caused by Bcl-xL deficiency was completely dependent on Bak and Bax, and surprisingly on Bid. This indicated that, in the absence of Bid, Bcl-xL is not required for the integrity of differentiated hepatocytes, suggesting a complicated interaction between core Bcl-2 family proteins and BH3-only proteins even in a physiological setting. Indeed, a small but significant level of tBid was present in wild-type liver under physiological conditions. tBid was capable of binding to Bcl-xL and displacing Bak and Bax from Bcl-xL, leading to release of cytochrome c from wild-type mitochondria. Bcl-xL-deficient mitochondria were more susceptible to tBid-induced cytochrome c release. Finally, administration of ABT-737, a pharmacological inhibitor of Bcl-2/Bcl-xL, caused Bak/Bax-dependent liver injury, but this was clearly ameliorated with a Bid KO background. Conclusion: Bid, originally considered to be a sensor for apoptotic stimuli, is constitutively active in healthy liver cells and is involved in the Bak/Bax-dependent mitochondrial cell death pathway. Healthy liver cells are addicted to a single Bcl-2-like molecule because of BH3 stresses, and therefore special caution may be required for the use of the Bcl-2 inhibitor for cancer therapy.(HEPATOLOGY 2009.).
