Publications by authors named "Masaru Kuwayama"

Sendai virus (SeV), a pneumotropic virus of rodents, has an accessory protein, V, and the V protein has been shown to interact with MDA5, inhibiting IRF3 activation and interferon-β production. In the present study, interaction of the V protein with various IRF3-activating proteins including MDA5 was investigated in a co-immunoprecipitation assay. We also investigated interaction of mutant V proteins from SeVs of low pathogenicity with MDA5.

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We applied a multiplex reverse transcription-PCR with fluorescent dye-labeled primers (fluorescent multiplex RT-PCR) for noroviruses (NoV), sapovirus (SaV), and human astrovirus (HAstV) to diagnose 71 outbreaks of acute gastroenteritis during July 2007 and May 2010 in Hiroshima prefecture. In this assay, the green, red, yellow, and blue fluorescence for NoV genogroup I, NoV genogroup II, SaV, and HAstV, respectively, were indicated on an agarose gel under ultraviolet light. In 61 virus-positive outbreaks confirmed by fluorescent multiplex RT-PCR, detection rates of outbreaks for NoVs, SaV, and HAstV were 96.

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We have developed simultaneous detection of eight genes associated with the five categories of diarrheagenic Escherichia coli by the multiplex PCR assay with Alexa Fluor-labeled primers. This assay can easily distinguish eight genes based on the size and color of amplified products without gel staining.

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Article Synopsis
  • A new RT-LAMP assay was developed to specifically detect novel influenza A (H1N1) of swine origin and seasonal subtypes (H1N1 and H3N2) without cross-reacting with other respiratory viruses.
  • The assay operates at 63 degrees Celsius for 40 minutes and uses Eriochrome Black T as an indicator, producing blue for positive results and purple for negatives.
  • Validation of the assay showed high agreement with real-time RT-PCR in testing samples, indicating its potential for rapid influenza A virus detection.
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To characterize Japanese encephalitis virus (JEV) strains recently prevalent in Japan, JEV surveillance was performed in pigs from 2002 to 2004. Eleven new JEV isolates were obtained and compared with previous isolates from Japan and other Asian countries. All of the isolates were classified into genotype 1 by nucleotide sequence analysis of the E gene.

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We developed a reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for the rapid detection of noroviruses (NoVs) in a genogroup-specific manner in a previous study. In this study, to detect NoVs more easily and simply, we have developed an RT-LAMP assay for the simultaneous detection of NoV genogroup I (GI) and II (GII) genomes in a single tube. The genogrouping was achieved by using fluorescence-labeled primers, and the green and red colors for GI and GII, respectively, sometimes with yellow color for GI and GII mixture, were indicated on the agarose gel under UV light at 312 nm.

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The sensitivity of rapid diagnostic kits to influenza B is lower than to influenza A. The cause-poor performance of the kit or the scarcity of viruses in type B specimens-has yet to be clarified. Using real-time PCR, we measured the amount of influenza viruses with nasopharyngeal aspirate fluid previously identified by virus isolation culture and passing the rapid diagnosis test by four types of kits, including the ESPLINE Influenza A&B-N (Fujirebio Corp.

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In this study, we developed a one-step, single-tube genogroup-specific reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for the detection of norovirus (NoV) genomes targeting from the C terminus of the RNA-dependent RNA polymerase gene to the capsid N-terminal/shell domain region. This is the first report on the development of an RT-LAMP assay for the detection of NoV genomes. Because of the diversity of NoV genotypes, we used 9 and 13 specially designed primers containing mixed bases for genogroup I (GI) and II (GII), respectively.

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In the 2004/05 influenza season there were epidemics of influenza caused by several types of viruses (type B and A (H3) viruses, and type B, A (H3), and A (H1) viruses) in many areas of Japan. In such epidemics a single individual could be co-infected with several influenza viruses. From February to March in 2005, we examined 15 patients who were positive for influenza type A and B viruses when tested with a rapid diagnostic kit.

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Article Synopsis
  • The study evaluated four rapid influenza diagnostic kits on 278 children suspected of having influenza between 2004 and 2005.
  • ESPLINE showed the best performance with 100% sensitivity and specificity for influenza A and 89% sensitivity for influenza B, while all kits were less effective for influenza B.
  • Quick Vue and Capilia had lower specificity, indicating a need for improvements in those tests.
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Effects of proteasome inhibitors on the replication of a paramyxovirus in comparison with the effects on replication of an orthomyxovirus and rhabdovirus were investigated. Treatment of Sendai virus (SeV)-infected LLC-MK2 cells with 50 microM MG132 reduced virus growth to ca. 1/10,000, and treatment with different concentrations of MG132 reduced virus growth in a dose-dependent manner.

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Cerebrospinal fluid specimens from 57 patients diagnosed with meningitis were tested for Japanese encephalitis virus. Total RNA was extracted from the specimens and amplified. Two products had highest homology with Nakayama strain and 2 with Ishikawa strain.

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We discussed the clinical features of 5 Japanese encephalitis (JE) cases which we experienced in 2002. Today there are few opportunities for a clinician to see JE patients. Until the 1950s, the number of JE patients was more than 2000 in Japan, but the annual cases of JE are decreasing remarkably due to the extermination of mosquitoes, thorough vaccination and improvement of environmental sanitation.

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Envelope viruses maturate by macromolecule assembly and budding. To investigate these steps, we generated virus-like particles (VLPs) by co-expression of structural proteins of Sendai virus (SeV), a prototype of the family Paramyxoviridae. Simultaneous expression of matrix (M), nucleo- (N), fusion (F), and hemagglutinin-neuraminidase (HN) proteins resulted in the generation of VLPs that had morphology and density similar to those of authentic virus particles, although the efficiency of release from cells was significantly lower than that of the virus.

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