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Ken-ichi Amano

Publications and source records attributed to Ken-ichi Amano.

10 recordsLinked to original sources
PubMed2006

Potent analgesic effects of a putative sodium channel blocker M58373 on formalin-induced and neuropathic pain in rats.

M58373, 4-[2-(4-hydroxy-4-{[N-(4-isopropoxyphenyl)-N-methylamino]methyl}piperidin-1-yl)ethyl]benzonitrile monohydrochloride, is a novel compound, which has an inhibitory activity on neurotoxin binding to the site 2 of voltage-gated sodium channels. In this study, we investigated the effects of M58373 on substance P release from sensory neurons in vitro and pain behaviors/responses in rats, compared with mexiletine. M58373 (1-10 microM) inhibited veratridine-induced release of substance P from dorsal root ganglion cells. In the formalin test, oral M58373 (0.3-10 mg/kg) reduced the time spent in nociceptive behaviors only in the late phase. In the neuropathic pain model, oral M58373 (1-10 mg/kg) attenuated mechanical allodynia and heat hyperalgesia in the nerve-injured paw without affecting normal responses in the uninjured paw. In contrast, oral mexiletine (10-100 mg/kg) had a narrow therapeutic dose range in both models because of the adverse effects on the central nervous system. These results suggest that M58373 is a favorable prototype for novel anti-neuropathic pain agents.

Analgesics↗
PubMed2006

Nosocomial outbreak of ceftazidime-resistant Serratia marcescens strains that produce a chromosomal AmpC variant with N235K substitution.

Serratia marcescens is a Gram-negative bacterium that is often associated with nosocomial infections. Here we analyzed the resistance mechanism of the ceftazidime-resistant S. marcescens nosocomial strains. The five S. marcescens urinary tract infection-associated isolates were positive for chromosomal ampC and bla(TEM-1). Four of the five strains, ES11, ES31, ES42, and ES46, were single clone and ceftazidime resistant. The fifth strain, ES71, was susceptible to ceftazidime. Analysis of the deduced amino acid sequence revealed a Glu-235-Lys substitution in the third amino acid of the third motif of AmpC from both ES46 and ES71, and a site-directed mutagenesis experiment confirmed that this substitution is involved in the ceftazidime resistance phenotype. However, the resistance phenotypes of strains ES46 and ES71 to ceftazidime were quite different from one another, indicating that another mechanism, in addition to the AmpC mutation, is also involved in the determination of the resistance phenotype of these strains. Basal AmpC activity was more than two times higher in strain ES46 than in ES71, which could result in the differing resistance phenotypes of these two strains. The clinical significance and prevalence of extended-spectrum cephalosporin-resistant S. marcescens strains harboring the mutated chromosomal ampC gene are unclear in Japan and remain to be elucidated.

Amino Acid Sequence↗
PubMed2005

[Weil-Felix test].

Explore the source record for details and available documents.

Agglutination Tests↗
PubMed2004

[Relationship between absolute humidity and influenza prevalence in Odate and Akita cities, Akita Prefecture, in 2001 and 2002].

The dynamics of influenza viruses in relation to one meteorological factor, absolute humidity, was investigated. The number of influenza patients, absolute humidity, and isolation of influenza viruses were compared between Odate City the north and Akita City in central Akita Prefecture from 2001 to 2002. The results were as follows: 1) In both Odate and Akita cities, Influenza A (H1N1 and H3N2) and Influenza B (Victoria and Yamagata) viruses were isolated when absolute humidity ranged between 2.7 and 8.8 g/m3. 2) In Akita City in 2002, the influenza viruses were isolated in May (weeks 20 and 22), and the absolute humidity was below 9 g/m3, suggesting that the influenza season lasted until May in this year. 3) A correlation between absolute humidity and isolation of influenza viruses was observed, and the influenza prevalence may occur below 9 g/m3 of absolute humidity. 4) In Odate and Akita cities, the absolute humidity of 10 g/m3, a level at which 5% of influenza viruses can survive after six hours, was observed from January to June and October to December. 5) Influenza prevalence show differential occurrence by time and place. Therefore, further research is required to clarify the absolute humidity related to influenza prevalence.

Humans↗
PubMed2003

Structural studies on the lipopolysaccharide core of Proteus OX strains used in Weil-Felix test: a mass spectrometric approach.

The core region of the lipopolysaccharides of Proteus group OX bacteria, which are used as antigens in Weil-Felix test for serodiagnosis of rickettsiosis, were studied by chemical degradations in combination with ESI FTMS, including infrared multi-photon dissociation (IRMPD) MS/MS and capillary skimmer dissociation. Structural variants of the inner core region were found to be the same as in Proteus non-OX strains that have been studied earlier. The outer core region has essentially the same structure in Proteus vulgaris OX19 (serogroup O1) and OX2 (serogroup O2) and a different structure in Proteus mirabilis OXK (serogroup O3). A fragmentation due to the rupture of the linkage between GlcN or GalN and GalA was observed in IRMPD-MS/MS of core oligosaccharides and found to be useful for screening of Proteus strains to assign structures of the relatively conserved inner core region and to select for further studies strains with distinct structures of a more variable outer core region.

Carbohydrate Sequence↗
PubMed2003

Measles virus suppresses interferon-alpha signaling pathway: suppression of Jak1 phosphorylation and association of viral accessory proteins, C and V, with interferon-alpha receptor complex.

To establish infections, viruses use various strategies to suppress the host defense mechanism, such as interferon (IFN)-induced antiviral state. We found that cells infected with a wild strain of measles virus (MeV) displayed nearly complete suppression of IFN-alpha-induced antiviral state, but not IFN-gamma-induced state. This phenomenon is due to the suppression of IFN-alpha-inducible gene expression at a transcriptional level. In the IFN-alpha signal transduction pathway, Jak1 phosphorylation induced by IFN-alpha is dramatically suppressed in MeV-infected cells; however, phosphorylation induced by IFN-gamma is not. We performed immunoprecipitation experiments using antibodies against type 1 IFN receptor chain 1 (INFAR1) and antibody against RACK1, which is reported to be a scaffold protein interacting with type I IFN receptor chain 2 and STAT1. These experiments indicated that IFNAR1 forms a complex containing the MeV-accessory proteins C and V, RACK1, and STAT1 in MeV-infected cells but not in uninfected cells. Composition of this complex in the infected cells altered little by IFN-alpha treatment. These results indicate that MeV suppresses the IFN-alpha, but not IFN-gamma, signaling pathway by inhibition of Jak1 phosphorylation. Our data suggest that functional disorder of the type I IFN receptor complex is due to "freezing" of the receptor through its association with the C and/or V proteins of MeV.

Animals↗
PubMed2002

[Typings of Campylobacter jejuni isolated from patients of 2 outbreak cases by genotypic and phenotypic methods].

We compared Campylobacter jejuni strains isolated from the patient stools associated with two food-borne diarrheal outbreak cases by the serotypic methods (Lior and Penner systems) and the genotypic methods (restriction fragment length polymorphism (RFLP) of flaA gene and pulsed-field gel electrophoresis (PFGE)). Fla-RFLP was based on the digestion of 410 bp DNA fragment by MboI restriction enzyme amplified from a 5' portion of C. jejuni flaA gene. Six distinctive fla-RFLP patterns were identified by examining 29 serotype reference strains and 58 strains isolated from the patients infected with C. jejuni independently. In the first outbreak case, 4 isolates were shown to be the same patterns each other by the fla-RFLP and PFGE, and by the Lior serotyping, except the Penner system that serotyped into 2 distinct types. On the other hand, in the second case, out of 10 isolates, 5 isolates were identical by the both genotypic and the both serotypic methods, and 4 isolates were not differentiated by the fla-RFLP and Penner system, but were separated into 4 types by PFGE in a little difference. The rest isolate was completely different from the other isolates by the all of methods used now. The findings suggest that the second case occurred by the infection of at least 3 different strains of C. jejuni.

Adolescent↗