Publications by authors named "Yuri Kato"

23 Publications

  • Page 1 of 1

Deletion of TRPC3 or TRPC6 Fails to Attenuate the Formation of Inflammation and Fibrosis in Non-alcoholic Steatohepatitis.

Biol Pharm Bull 2021 ;44(3):431-436

Graduate School of Pharmaceutical Sciences, Kyushu University.

Non-alcoholic steatohepatitis (NASH) is a disease that has progressed from non-alcoholic fatty liver disease (NAFLD) and is characterized by inflammation and fibrosis. Two transient receptor potential canonical (TRPC) subfamily members, TRPC3 and TRPC6 (TRPC3/6), reportedly participate in the development of fibrosis in cardiovascular and renal systems. We hypothesized that TRPC3/6 may also participate in NASH fibrosis. We evaluated the effects of TRPC3 or TRPC6 functional deficiency in a NASH mouse model using choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD). Wild-type (WT) and TRPC3 or TRPC6 gene-deficient (KO) mice were fed with CDAHFD or standard diet for 6 weeks. The CDAHFD-induced body weight loss in TRPC6 KO mice was significantly lower compared with WT mice with CDAHFD. CDAHFD treatment significantly increased TRPC3 mRNA expression level and tissue weight in WT liver, which were suppressed in TRPC3 KO mice. However, either systemic deletion of TRPC3 or TRPC6 failed to attenuate liver steatosis, inflammation and fibrosis. These results imply that TRPC3 and TRPC6 are unlikely to be involved in liver dysfunction and fibrosis of NASH model mice.
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http://dx.doi.org/10.1248/bpb.b20-00903DOI Listing
January 2021

Regulation of catalytic activity and nucleolar localization of rat DNA topoisomerase IIα through its C-terminal domain.

Genes Genet Syst 2021 Mar 6;95(6):291-302. Epub 2021 Feb 6.

Department of Biochemistry, Faculty of Science, Okayama University of Science.

Type II DNA topoisomerase (topo II) catalyzes double-stranded DNA cleavage and re-ligation, thus solving problems in DNA topology. Vertebrates have two isozymes (α and β). Recently, the C-terminal regulatory domain (CRD), which regulates catalytic activity and subnuclear localization by associating with RNA, was identified within the C-terminal domain (CTD) of rat topo IIβ. In contrast, it is unclear whether a β CRD-like domain is present in the CTD of topo IIα. In this study, we aimed to identify an RNA-mediated regulatory domain in the rat topo IIα CTD. First, we exchanged the CTDs of rat topo IIα (amino acids 1,192-1,528) and β (1,201-1,614) and examined the two chimeras' in vitro catalytic activities. Interestingly, the relaxation activities of topo IIα WT enzyme and both of the CTD-swapped mutants were inhibited in the presence of isolated cellular RNA, suggesting that the α CTD is involved in the RNA-mediated regulation of catalytic activity in topo IIα. The results of on-bead assays using a CTD-deleted mutant of rat topo IIα indicated that the RNA-mediated inhibition of the relaxation activity was caused by an interaction between the α CTD and RNA. Further, to identify the domain within the CTD that is associated with subnuclear localization of rat topo IIα, we transiently expressed EGFP-tagged CTD deletion mutants in human cells. The data indicated that the 1,192-1,289 region of rat topo IIα was required for targeting the enzyme to nucleoli. Finally, a relaxation assay using 1-1,289 and Δ1,192-1,289 truncated mutants indicated that the 1,192-1,289 region is involved in RNA-mediated inhibition. These results indicated that the CTD of rat topo IIα, containing the 1,192-1,289 region, is involved in the regulation of catalytic activity by associating with RNA, as well as in the localization to nucleoli in interphase cells.
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http://dx.doi.org/10.1266/ggs.20-00038DOI Listing
March 2021

A Recurrent Case of Adult-onset Still's Disease with Concurrent Acalculous Cholecystitis and Macrophage Activation Syndrome/Hemophagocytic Lymphohistiocytosis Successfully Treated with Combination Immunosuppressive Therapy.

Intern Med 2021 Jun 1;60(12):1955-1961. Epub 2021 Feb 1.

Department of Rheumatology, Yokohama Rosai Hospital, Japan.

We herein report the case of 21-year-old female diagnosed with adult-onset Still's disease (AOSD) three years earlier who presented with fever and right upper abdominal pain. She was diagnosed with acute acalculous cholecystitis (AAC) based on hepatic dysfunction, elevated C-reactive protein, and gallbladder wall thickening on abdominal ultrasound. Based on the presence of pancytopenia, hyperferritinemia, and hemophagocytosis by a bone marrow examination, she was diagnosed with macrophage activation syndrome (MAS)/hemophagocytic lymphohistiocytosis (HLH) which was refractory to glucocorticoid pulse therapy. The combination of intravenous cyclosporine A with glucocorticoids was able to successfully control the disease activity of AOSD-related AAC and MAS/HLH.
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http://dx.doi.org/10.2169/internalmedicine.5781-20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263191PMC
June 2021

Modulation of P2YR expression exacerbates pressure overload-induced cardiac remodeling in mice.

Sci Rep 2020 08 18;10(1):13926. Epub 2020 Aug 18.

National Institute for Physiological Sciences (NIPS), National Institutes of Natural Sciences, Okazaki, Aichi, 444-8787, Japan.

Cardiac tissue remodeling caused by hemodynamic overload is a major clinical outcome of heart failure. Uridine-responsive purinergic P2Y receptor (P2YR) contributes to the progression of cardiovascular remodeling in rodents, but it is not known whether inhibition of P2YR prevents or promotes heart failure. We demonstrate that inhibition of P2YR promotes pressure overload-induced sudden death and heart failure in mice. In neonatal cardiomyocytes, knockdown of P2YR significantly attenuated hypertrophic growth and cell death caused by hypotonic stimulation, indicating the involvement of P2YR in mechanical stress-induced myocardial dysfunction. Unexpectedly, compared with wild-type mice, deletion of P2YR promoted pressure overload-induced sudden death, as well as cardiac remodeling and dysfunction. Mice with cardiomyocyte-specific overexpression of P2YR also exhibited cardiac dysfunction and severe fibrosis. In contrast, P2YR deletion had little impact on oxidative stress-mediated cardiac dysfunction induced by doxorubicin treatment. These findings provide overwhelming evidence that systemic inhibition of P2YR exacerbates pressure overload-induced heart failure in mice, although P2YR in cardiomyocytes contributes to the progression of cardiac fibrosis.
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http://dx.doi.org/10.1038/s41598-020-70956-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7434875PMC
August 2020

High Reactivity of α-Boryl Radical of Potassium Alkyltrifluoroborate in Atom-Transfer Radical Addition.

Org Lett 2020 Aug 25;22(16):6234-6238. Epub 2020 Jun 25.

Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.

We found that the α-boryl radical of potassium alkyltrifluoroborate shows higher reactivity compared to the α-boryl radicals of alkylboronic acid pinacol ester and alkyl -methyl imidodiacetic acid (MIDA) boronate in the halogen atom abstraction step of atom-transfer radical addition (ATRA) between alkyl bromide and vinylborons. In this research, an ATRA of alkyl halides with potassium vinyltrifluoroborate furnished unique alkylborons, which are difficult to synthesize by other methods.
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http://dx.doi.org/10.1021/acs.orglett.0c01807DOI Listing
August 2020

Node-Localized Transporters of Phosphorus Essential for Seed Development in Rice.

Plant Cell Physiol 2020 Aug;61(8):1387-1398

Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046 Japan.

About 60-85% of total phosphorus (P) in cereal crops is finally allocated to seeds, where it is required for seed development, germination and early growth. However, little is known about the molecular mechanisms underlying P allocation to seeds. Here, we found that two members (OsPHO1;1 and OsPHO1;2) of the PHO1 gene family are involved in the distribution of P to seeds in rice. Both OsPHO1;1 and OsPHO1;2 were localized to the plasma membrane and showed influx transport activities for inorganic phosphate. At the reproductive stage, both OsPHO1;1 and OsPHO1;2 showed higher expression in node I, the uppermost node connecting to the panicle. OsPHO1;1 was mainly localized at the phloem region of diffuse vascular bundles (DVBs) of node I, while OsPHO1;2 was expressed in the xylem parenchyma cells of the enlarged vascular bundles (EVBs). In addition, they were also expressed in the ovular vascular trace, the outer layer of the inner integument (OsPHO1;1) and in the nucellar epidermis (OsPHO1;2) of caryopses. Knockout of OsPHO1;2, as well as OsPHO1;1 to a lesser extent, decreased the distribution of P to the seed, resulting in decreased seed size and delayed germination. Taken together, OsPHO1;2 expressed in node I is responsible for the unloading of P from the xylem of EVBs, while OsPHO1;1 is involved in reloading P into the phloem of DVBs for subsequent allocation of P to seeds. Furthermore, OsPHO1;1 and OsPHO1;2 expression in the caryopsis is important for delivering P from the maternal tissues to the filial tissues for seed development.
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http://dx.doi.org/10.1093/pcp/pcaa074DOI Listing
August 2020

A 4.8-μV-Noise CMOS-Microelectrode Array With Density-Scalable Active Readout Pixels via Disaggregated Differential Amplifier Implementation.

Front Neurosci 2019 21;13:234. Epub 2019 Mar 21.

Research Division 1, Sony Semiconductor Solutions Corporation, Kanagawa, Japan.

We demonstrate a 4.8-μV noise microelectrode array (MEA) based on the complementary-metal-oxide-semiconductor active-pixel-sensors readout technique with disaggregated differential amplifier implementation. The circuit elements of the differential amplifier are divided into a readout pixel, a reference pixel, and a column circuit. This disaggregation contributes to the small area of the readout pixel, which is less than 81 μm. We observed neuron signals around 100 μV with 432 electrodes in a fabricated prototype chip. The implementation has technological feasibility of up to 12-μm-pitch electrode density and 6,912 readout channels for high-spatial resolution mapping of neuron network activity.
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http://dx.doi.org/10.3389/fnins.2019.00234DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6437115PMC
March 2019

Vesicular nucleotide transporter mediates ATP release and migration in neutrophils.

J Biol Chem 2018 03 23;293(10):3770-3779. Epub 2018 Jan 23.

From the Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8530, Japan,

Neutrophils migrate to sites infected by pathogenic microorganisms. This migration is regulated by neutrophil-secreted ATP, which stimulates neutrophils in an autocrine manner through purinergic receptors on the plasma membrane. Although previous studies have shown that ATP is released through channels at the plasma membrane of the neutrophil, it remains unknown whether it is also released through alternate secretory systems involving vesicular mechanisms. In this study, we investigated the possible involvement of vesicular nucleotide transporter (VNUT), a key molecule for vesicular storage and nucleotide release, in ATP secretion from neutrophils. RT-PCR and Western blotting analysis indicated that VNUT is expressed in mouse neutrophils. Immunohistochemical analysis indicated that VNUT mainly colocalized with matrix metalloproteinase-9 (MMP-9), a marker of tertiary granules, which are secretory organelles. In mouse neutrophils, ATP release was inhibited by clodronate, which is a potent VNUT inhibitor. Furthermore, neutrophils from mice did not release ATP and exhibited significantly reduced migration and These findings suggest that tertiary granule-localized VNUT is responsible for vesicular ATP release and subsequent neutrophil migration. Thus, these findings suggest an additional mechanism through which ATP is released by neutrophils.
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http://dx.doi.org/10.1074/jbc.M117.810168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5846168PMC
March 2018

Efficient Mass Spectral Analysis of Active Transporters Overexpressed in Escherichia coli.

J Proteome Res 2018 03 5;17(3):1108-1119. Epub 2018 Feb 5.

Department of Molecular Membrane Biology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama 700-8530, Japan.

Structural analysis of purified active membrane proteins can be performed by mass spectrometry (MS). However, no large-scale expression systems for active eukaryotic membrane proteins are available. Moreover, because membrane proteins cannot easily be digested by trypsin and ionized, they are difficult to analyze by MS. We developed a method for mass spectral analysis of eukaryotic membrane proteins combined with an overexpression system in Escherichia coli. Vesicular glutamate transporter 2 (VGLUT2/SLC17A6) with a soluble α-helical protein and histidine tag on the N- and C-terminus, respectively, was overexpressed in E. coli, solubilized with detergent, and purified by Ni-NTA affinity chromatography. Proteoliposomes containing VGLUT2 retained glutamate transport activity. For MS analysis, the detergent was removed from purified VGLUT2 by trichloroacetic acid precipitation, and VGLUT2 was then subjected to reductive alkylation and tryptic digestion. The resulting peptides were detected with 88% coverage by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS with or without liquid chromatography. Vesicular excitatory amino acid transporter and vesicular acetylcholine transporter were also detected with similar coverage by the same method. Thus this methodology could be used to analyze purified eukaryotic active transporters. Structural analysis with chemical modifiers by MS could have applications in functional binding analysis for drug discovery.
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http://dx.doi.org/10.1021/acs.jproteome.7b00777DOI Listing
March 2018

Twenty-four-micrometer-pitch microelectrode array with 6912-channel readout at 12 kHz via highly scalable implementation for high-spatial-resolution mapping of action potentials.

Biointerphases 2017 Dec 19;12(5):05F402. Epub 2017 Dec 19.

Research Division, Sony Semiconductor Solutions Corporation, 4-14-1 Asahi-cho, Atsugi-shi, Kanagawa 243-0014, Japan.

A 24-μm-pitch microelectrode array (MEA) with 6912 readout channels at 12 kHz and 23.2-μV random noise is presented. The aim is to reduce noise in a "highly scalable" MEA with a complementary metal-oxide-semiconductor integration circuit (CMOS-MEA), in which a large number of readout channels and a high electrode density can be expected. Despite the small dimension and the simplicity of the in-pixel circuit for the high electrode-density and the relatively large number of readout channels of the prototype CMOS-MEA chip developed in this work, the noise within the chip is successfully reduced to less than half that reported in a previous work, for a device with similar in-pixel circuit simplicity and a large number of readout channels. Further, the action potential was clearly observed on cardiomyocytes using the CMOS-MEA. These results indicate the high-scalability of the CMOS-MEA. The highly scalable CMOS-MEA provides high-spatial-resolution mapping of cell action potentials, and the mapping can aid understanding of complex activities in cells, including neuron network activities.
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http://dx.doi.org/10.1116/1.4997358DOI Listing
December 2017

Identification of a vesicular ATP release inhibitor for the treatment of neuropathic and inflammatory pain.

Proc Natl Acad Sci U S A 2017 Aug 18;114(31):E6297-E6305. Epub 2017 Jul 18.

Advanced Science Research Center, Okayama University, Okayama 700-8530, Japan;

Despite the high incidence of neuropathic and inflammatory pain worldwide, effective drugs with few side effects are currently unavailable for the treatment of chronic pain. Recently, researchers have proposed that inhibitors of purinergic chemical transmission, which plays a key role in the pathological pain response, may allow for targeted treatment of pathological neuropathic and inflammatory pain. However, such therapeutic analgesic agents have yet to be developed. In the present study, we demonstrated that clodronate, a first-generation bisphosphonate with comparatively fewer side effects than traditional treatments, significantly attenuates neuropathic and inflammatory pain unrelated to bone abnormalities via inhibition of vesicular nucleotide transporter (VNUT), a key molecule for the initiation of purinergic chemical transmission. In vitro analyses indicated that clodronate inhibits VNUT at a half-maximal inhibitory concentration of 15.6 nM without affecting other vesicular neurotransmitter transporters, acting as an allosteric modulator through competition with Cl A low concentration of clodronate impaired vesicular ATP release from neurons, microglia, and immune cells. In vivo analyses revealed that clodronate is more effective than other therapeutic agents in attenuating neuropathic and inflammatory pain, as well as the accompanying inflammation, in wild-type but not mice, without affecting basal nociception. These findings indicate that clodronate may represent a unique treatment strategy for chronic neuropathic and inflammatory pain via inhibition of vesicular ATP release.
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http://dx.doi.org/10.1073/pnas.1704847114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5547629PMC
August 2017

Analysis of the origin of inherited chromosomally integrated human herpesvirus 6 in the Japanese population.

J Gen Virol 2017 Jul 12;98(7):1823-1830. Epub 2017 Jul 12.

Department of Pediatrics, Fujita Health University School of Medicine, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan.

Integration of the complete human herpesvirus 6 (HHV-6) genome into the telomere of a chromosome has been reported in some individuals (inherited chromosomally integrated HHV-6; iciHHV-6). Since the proportion of iciHHV-6-positive individuals with integration in chromosome 22 is high in Japan, we hypothesized a founder effect. In this study, we sought to elucidate the reason for the high proportion of viral integrations into chromosome 22. We analyzed six cases of iciHHV-6A and two cases of iciHHV-6B, including one iciHHV-6A case with a matched sample from a father and one iciHHV-6B case with a matched sample from a mother. In iciHHV-6A, the same copy numbers of viral telomeric repeat sequences (TRS) and the same five microsatellite markers were detected in both the index case and paternal sample. Moreover, the same five microsatellite markers were demonstrated in four cases and the same copy numbers of viral TRS were demonstrated in two pairs of two cases. The present microsatellite analysis suggested that the viral genomes detected in some iciHHV-6A patients were derived from a common ancestral integration.
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http://dx.doi.org/10.1099/jgv.0.000834DOI Listing
July 2017

Effect of vonoprazan on the treatment of artificial gastric ulcers after endoscopic submucosal dissection: Prospective randomized controlled trial.

Dig Endosc 2017 Jul 5;29(5):576-583. Epub 2017 Apr 5.

Department of Gastroenterology, Machida Municipal Hospital, Tokyo, Japan.

Background And Aim: Proton pump inhibitors are effective for the treatment of gastric ulcers after endoscopic submucosal dissection (ESD). However, the most excellent therapy is controversial. Vonoprazan, an active potassium-competitive acid blocker, has a strong gastric acid secretion inhibitory effect, but its efficacy for the treatment of post-ESD gastric ulcers is unclear. Herein, we aimed to determine the healing effect of vonoprazan on post-ESD gastric ulcers.

Methods: We carried out a prospective randomized controlled trial examining 92 patients who had undergone ESD for the treatment of gastric neoplasms between April 2015 and June 2016 at Machida Municipal Hospital. Patients were treated with 20 mg/day vonoprazan (V group) or 20 mg/day esomeprazole (E group) for 8 weeks. We evaluated the 8-week cure rate for artificial ulcers and any complications after ESD.

Results: A total of 80 patients (median age, 73.5 years; 71.3% male) were analyzed. Cure rate for the V group was significantly higher than that for the E group (94.9% [37/39] vs 78.0% [32/41], respectively; P = 0.049). In a multivariate analysis, only vonoprazan was correlated with ulcer healing (odds ratio = 6.33; 95% CI = 1.21-33.20; P = 0.029). Delayed bleeding was experienced only in the E group (7.3% [3/41]), but no significant difference compared with the V group was observed (P = 0.241).

Conclusion: Vonoprazan was significantly superior to esomeprazole for the healing of post-ESD gastric ulcers and should be considered as a treatment of first choice.
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http://dx.doi.org/10.1111/den.12857DOI Listing
July 2017

Intravenous injection of low-dose flurbiprofen axetil for preventing post-ERCP pancreatitis in high-risk patients: An interim analysis of the trial.

Endosc Int Open 2016 Oct 21;4(10):E1078-E1082. Epub 2016 Sep 21.

Department of Gastroenterology and Hepatology, Yokohama City University School of Medicine, Yokohama, Japan.

Several meta-analyses and randomized control trials have demonstrated the efficacy of rectal nonsteroidal anti-inflammatory drugs for preventing post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). Diclofenac or indomethacin was administered at a dose of 100 mg in those studies, which may be too high for Asian population. In addition, rectal administration can be considered complicated. This study was a prospective, randomized, placebo-controlled trial. Patients with a PEP risk score ≥ 1 were randomly assigned to receive intravenous injection of 50 mg flurbiprofen axetil (flurbiprofen group) or saline only (placebo group). The primary outcome was reduced PEP. The secondary outcome was amylase level after 2 hours of ERCP as a predictor of PEP. (Clinical Trials.gov, ID UMIN000011322) In total, 144 patients were enrolled from August 2013 to March 2015. We performed an interim analysis of the first 100 patients: 47 received flurbiprofen axetil and 53 received placebo. PEP occurred in 11 patients (11 %): 2 of 47 (4.3 %) in the flurbiprofen group and 9 of 53 (17 %) in the placebo group ( = 0.042). Relative risk reduction was 62.4 %. Hyperamylasemia did not differ significantly (17.0 % vs. 26.4 %,  = 0.109). This analysis resulted in early termination of the study for ethical reasons. Intravenous injection of low-dose flurbiprofen axetil after ERCP can reduce the incidence of PEP in high-risk patients.
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http://dx.doi.org/10.1055/s-0042-115172DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5063645PMC
October 2016

Cycling probe-based real-time PCR for the detection of Human herpesvirus 6A and B.

J Med Virol 2016 09 16;88(9):1628-35. Epub 2016 Mar 16.

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi, Japan.

Human herpesvirus 6 (HHV-6) is classified as two distinct species: HHV-6A and B. HHV-6B infection can cause several clinical manifestations in transplant recipients including encephalitis, bone marrow suppression, and pneumonitis. In contrast to HHV-6B, the clinical features of HHV-6A infection remain largely undefined. Herein, we developed a multiplex cycling probe real-time PCR that discriminated between HHV-6A and HHV-6B. The assay was HHV-6-specific and no cross amplification was demonstrated for other herpesviruses. Moreover, the assay had a broad, linear dynamic range of detection between 1 and 10(6) copies of viral DNA. The quantification of HHV-6A DNA was suppressed by an excess amount of HHV-6B DNA (1 × 10(6) copies/tube) in the multiplex PCR assay; however, 1 × 10(6) copies/tube of HHV-6A DNA did not affect the quantification of 1 × 10(4) copies/tube of HHV-6B DNA. To determine the reliability of the assay for analysis of clinical specimens, DNAs extracted from the peripheral blood of hematopoietic stem cell transplant recipients were assayed using our multiplex real-time PCR versus the standard TaqMan PCR. Strong correlations were demonstrated between the two different assay systems for both HHV-6A (R(2)  = 0.913) and HHV-6B (R(2)  = 0.909). Therefore, our multiplex HHV-6 species-specific cycling probe real-time PCR is useful for evaluating the precise copy numbers of HHV-6A and B in transplant recipients. However, as HHV-6A copy numbers was affected by presence of high copies of HHV-6B DNA (1 × 10(6) copies/tube), it may be difficult to measure precise copy numbers of HHV-6A in inherited chromosomally integrated HHV-6B patient. J. Med. Virol. 88:1628-1635, 2016. © 2016 Wiley Periodicals, Inc.
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http://dx.doi.org/10.1002/jmv.24513DOI Listing
September 2016

DNA-binding activity of rat DNA topoisomerase II α C-terminal domain contributes to efficient DNA catenation in vitro.

J Biochem 2016 Mar 1;159(3):363-9. Epub 2015 Nov 1.

Department of Biochemistry, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan and.

DNA topoisomerase IIα (topo IIα) is an essential enzyme for resolution of DNA topologies arising in DNA metabolic reactions. In proliferating cells, topo II activities of DNA catenation or decatenation are required for condensation of chromosomes and segregation of chromatids. Recent studies suggest that the C-terminal domain (CTD) of human topo IIα is required for localization to mitotic chromosomes. Here, we show that the CTD of topo IIα is also associated with efficient DNA catenation in vitro, based on comparison of wild-type (WT) rat topo IIα and its deletion mutants. Unlike WT, the CTD truncated mutant (ΔCTD) lacked linear DNA binding activity, but could bind to negatively supercoiled DNA similarly to WT. The CTD alone showed linear DNA-binding activity. ΔCTD mediated formation of a DNA catenane in the presence of polyethylene glycol, which enhances macromolecular association. These results indicate that DNA-binding activity in the CTD of topo IIα concentrates the enzyme in the vicinity of condensed DNA and allows topo IIα to efficiently form a DNA catenane.
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http://dx.doi.org/10.1093/jb/mvv110DOI Listing
March 2016

Effects of phytochemicals on in vitro anti-inflammatory activity of Bifidobacterium adolescentis.

Biosci Biotechnol Biochem 2015 27;79(5):799-807. Epub 2015 Feb 27.

a Department of Bioscience , Fukui Prefectural University , Fukui , Japan.

Probiotics have been shown to improve the condition of not only the human gastrointestinal tract but also the entire body. We found that quercetin enhances the anti-inflammatory activity of Bifidobacterium adolescentis, which is abundant in human intestines. Here, we assessed whether certain phytochemicals could enhance the anti-inflammatory activity of B. adolescentis. Bifidobacteria were anaerobically cultured with phytochemicals for 3 h, and the anti-inflammatory activity of the supernatants was estimated by testing their ability to inhibit nitric oxide (NO) production by lipopolysaccharide-stimulated RAW264 macrophages. Of the 55 phytochemicals tested, phloretin, (+)-taxifolin, and (-)-epigallocatechin gallate as well as quercetin-3-O-glucoside and quercetin-4'-O-glucoside were similar to quercetin in promoting NO suppression by B. adolescentis. In addition, the phytochemicals excluding quercetin increased the concentrations of lactic and acetic acids in the co-culture supernatants. These results suggest that some phytochemicals may activate the anti-inflammatory function of B. adolescentis.
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http://dx.doi.org/10.1080/09168451.2015.1006566DOI Listing
May 2016

Pd(II)-catalyzed allylic C-H amination for the preparation of 1,2- and 1,3-cyclic ureas.

Org Lett 2015 Feb 30;17(4):888-91. Epub 2015 Jan 30.

Faculty of Pharmacy, Meijo University , 150 Yagotoyama, Tempaku-ku, Nagoya 468-8503, Japan.

A general synthesis of 1,2- and 1,3-cyclic ureas is accomplished by intramolecular allylic C-H amination employing Pd(TFA)2/bis-sulfoxide as a catalyst. By careful modification of substrates and catalyst, a variety of 1,2-cyclic ureas are accessible from not previously employed terminal olefins substituted in allylic or vinylic positions. Furthermore, MS4A is found to be an effective additive for the synthesis of 1,3-cyclic ureas in good yields and excellent diastereoselectivities.
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http://dx.doi.org/10.1021/ol5037453DOI Listing
February 2015

Copy numbers of telomeric repeat sequences of human herpesvirus 6B in clinical isolates: possibility of mixed infections.

J Clin Microbiol 2014 Feb 13;52(2):419-24. Epub 2013 Nov 13.

Department of Clinical Laboratory, Fujita Health University Hospital, Toyoake, Japan.

In order to determine whether mixed infections of human herpesvirus 6B (HHV-6B) occur in immunocompetent and immunocompromised individuals, we examined the copy numbers of telomeric repeat sequences (TRS) of clinical isolates. In clinical isolates obtained from patients with exanthem subitum caused by primary HHV-6B infection, PCR products with HHV-6B TRS ranging between 400 and 800 bp were amplified. PCR products of various sizes were amplified in four clinical isolates from drug-induced hypersensitivity syndrome (DIHS) patients and 15 isolates from hematopoietic stem cell transplant (HSCT) recipients with HHV-6B reactivation. Based on the sequence analysis of the PCR products, the copy numbers of TRS in DIHS and HSCT patients were between 42 and 82 and 22 and >90, respectively. For two of the HSCT recipients, HHV-6B TRS PCR products of different sizes were detected in several isolates from each patient, which suggests mixed HHV-6B infections. In two of the posttransplant HHV-6B encephalitis patients, the sizes of the TRS nested PCR products amplified from the reactivated virus detected in the central nervous system differed from those of the virus detected in initial isolates from peripheral blood mononuclear cells. Taken together, these results suggest that PCR analysis of TRS copy number is a reliable tool for the discrimination of HHV-6B clinical isolates. Additionally, mixed HHV-6B infections occurred in HSCT recipients, and in some cases, compartmentalization of the HHV-6B strains to the central nervous system versus the blood compartment occurred in posttransplant HHV-6B encephalitis patients.
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http://dx.doi.org/10.1128/JCM.02192-13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3911338PMC
February 2014

Inhibitors of ATP release inhibit vesicular nucleotide transporter.

Biol Pharm Bull 2013 ;36(11):1688-91

Department of Membrane Biochemistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University.

Vesicular nucleotide transporter (VNUT) is responsible for vesicular ATP storage in ATP-secreting cells. In the present study, we examined the effects on VNUT-mediated transport of ATP release inhibitors such as ATP-binding cassette (ABC) proteins, hemichannels, maxi anion channels and P2X7 receptor. The ATP transport activity of proteoliposomes containing purified human VNUT was blocked by glibenclamide, carbenoxolone, 18 α-glycyrrhetinic acid, flufenamic acid, arachidonic acid and A438079 without the formation of Δψ (positive inside) as a driving force being affected. Thus, inhibitors of ATP release may inhibit VNUT and subsequent ATP release, since the previous works proved that inhibitors of ATP release blocked VNUT-mediated ATP release at the cell level.
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http://dx.doi.org/10.1248/bpb.b13-00544DOI Listing
June 2014

Expression and purification of bioactive hemagglutinin protein of highly pathogenic avian influenza A (H5N1) in silkworm larvae.

J Virol Methods 2013 Dec 13;194(1-2):271-6. Epub 2013 Sep 13.

Department of Bioscience, Graduate School of Science and Technology, Japan.

The hemagglutinin (HA) of avian influenza viruses plays a very important role in the infection of host cells. In this study, the HA gene of the highly pathogenic avian influenza H5N1 virus was cloned and expressed in silkworm larvae. The expressed recombinant HA (rHA) was purified using fetuin-agarose chromatography and Superdex 200 10/300 GL gel filtration chromatography, and the identity of purified rHA was confirmed by SDS-PAGE and Western blot. Approximately 500 μg of purified rHA was obtained from a total of 30 silkworm larvae, suggesting the high efficiency of the silkworm expression system. The purified rHA bound to a rabbit polyclonal antibody against influenza A virus H5N1 (avian flu) HA, suggesting its antigenicity and potential application in vaccine development. Gel filtration chromatography showed that purified HA was present in the void volume fractions, indicating that rHA may form an oligomer. The rHA bound to poly{Neu5Acα2,3LacNAcβ-O[(CH₂)₅NHCO]₂(CH₂)₅NH-/γ-PGA}, which mimics an avian type receptor, but did not bind to γ-polyglutamic acid or human type receptor mimic, poly{Neu5Acα2,6LacNAcβ-O[(CH₂)₅NHCO]₂(CH₂)₅NH-/γ-PGA}, suggesting that it could be utilized as a blocking agent against infection by highly pathogenic influenza viruses.
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http://dx.doi.org/10.1016/j.jviromet.2013.08.040DOI Listing
December 2013

Kinetics of cytokine and chemokine responses in patients with primary human herpesvirus 6 infection.

J Clin Virol 2011 Jan 28;50(1):65-8. Epub 2010 Oct 28.

Department of Pediatrics, Fujita Health University School of Medicine, Toyoake, Aichi 4701192, Japan.

Background: Cytokines and chemokines induced by human herpesvirus 6 (HHV-6) infection may play an important role in the observed HHV-6-associated clinical complications. However, basic data for cytokine and chemokine synthesis in primary HHV-6 infected patient without complication is lacking.

Objective: Aim of this study was to elucidate basic kinetic data for expressions of cytokines and chemokines in patients with primary HHV-6 infection without complication.

Study Design: Twenty-six patients suffering from fever were enrolled in this study. Fourteen biomarkers were measured in 74 serially collected sera samples from 26 patients. Additionally, serum samples obtained from 14 healthy children were used for control.

Results: Twenty of the 26 patients were diagnosed with primary HHV-6 infection based on viral isolation and serological analysis. The mean age (P=0.1289) and proportion of males to females (P=0.9999) between the patients with and without primary HHV-6 infection were not statistically different. At the acute phase of the disease, three cytokines (IFN-γ; P=0.0046, IL-2; P=0.0366, and IL-4; P=0.0255) and one chemokine (MCP-1; P=0.0019) were significantly higher in patients with primary HHV-6 infection compared to those without infection. Interleukin-5 levels during the convalescent period were significantly higher in patients with HHV-6 infection (P=0.0205). By 1 month post-infection, cytokine and chemokine expression had returned to almost basal levels.

Conclusion: As suggested by the previous in vitro studies, present in vivo analysis also suggests that HHV-6 has potency for induction of cytokines and chemokines.
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http://dx.doi.org/10.1016/j.jcv.2010.09.017DOI Listing
January 2011

Pyridylazulenes: synthesis, color changes, and structure of the colored product.

J Org Chem 2007 Feb;72(3):744-9

Department of Clinical Nutrition, Faculty of Health Science, Suzuka University of Medical Science, Suzuka, Mie 510-0293, Japan.

A facile method for the synthesis of 1- and 2-pyridylazulenes, and of 1,3-dipyridylazulenes, is described. Color and spectral changes of these pyridylazulenes upon the addition of either acid or metal ions were investigated in detail. The color changed from blue to red upon the addition of trifluoroacetic acid or soft metal ions, depending on the substitution patterns of the pyridyl group on the azulene skeleton. The structures of the protonated or coordinated products were examined on the basis of the spectral data. It was found that the protonation or coordination of metal ions occurred on the nitrogen atom of the pyridine ring, but not on the carbon atom of azulene ring. The transition intervals of several pyridylazulenes for use as pH indicators were also determined.
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http://dx.doi.org/10.1021/jo061684hDOI Listing
February 2007
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