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Search Results: 1 - 10 of 2165 matches for " Hideki Hasegawa "
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Pathology of Kaposi's sarcoma-associated herpesvirus infection
Hideki Hasegawa,Harutaka Katano
Frontiers in Microbiology , 2011, DOI: 10.3389/fmicb.2011.00175
Abstract: Kaposi’s sarcoma-associated herpesvirus (KSHV; human herpesvirus 8) is a human herpesvirus, classified as a gamma-herpesvirus. KSHV is detected in Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and some cases of multicentric Castleman’s disease (MCD). Similar to other herpes viruses, there are two phases of infection, latent and lytic. In KSHV-associated malignancies such as KS and PEL, KSHV latently infects almost all tumor cells. Quantitative PCR analysis revealed that each tumor cell contains one copy of KSHV in KS lesions. The oncogenesis by KSHV has remained unclear. Latency-associated nuclear antigen (LANA)-1 plays an important role in the pathogenesis of KSHV-associated malignancies through inhibition of apoptosis and maintenance of latency. Because all KSHV-infected cells express LANA-1, LANA-1 immunohistochemistry is a useful tool for diagnosis of KSHV infection. KSHV encodes some homologs of cellular proteins including cell-cycle regulators, cytokines, and chemokines, such as cyclin D, G-protein-coupled protein, interleukin-6, and macrophage inflammatory protein-1 and -2. These viral proteins mimic or disrupt host cytokine signals, resulting in microenvironments amenable to tumor growth. Lytic infection is frequently seen in MCD tissues, suggesting a different pathogenesis from KS and lymphoma.
Expression of Acetaldehyde Dehydrogenase Gene Increases Hydrogen Production and Acetate Consumption by Rhodobacter sphaeroides  [PDF]
Shinya Hasegawa, Jyumpei Kobayashi, Tomoe Komoriya, Hideki Kohno, Kazuaki Yoshimune
Energy and Power Engineering (EPE) , 2015, DOI: 10.4236/epe.2015.79037
Abstract: Rhodobacter sphaeroides RV (RV) produces high yields of hydrogen from organic acids in the presence of light. The hydrogen production from acetate is lower than that from lactate, probably because of its low ability to metabolize acetate. In this study, gene of acetaldehyde dehydrogenase (ACDH, EC 1.2.1.10) that catalyzes the reversible conversion of acetaldehyde and CoA to acetyl-CoA with the concurrent reduction of NAD to NADH, is overexpressed in the RV strain. The produced acetyl-CoA can be oxidized to carbon dioxide in the tricarboxylic acid (TCA) cycle, wherein electrons are generated and used for hydrogen production. The byproduct NADH can be used as reducing agent for acetate to produce acetaldehyde by acetate dehydrogenase. The recombinant RV strain (RVAC) expressing the ACDH gene showed ACDH activity with a specific activity of 3.2 mU/ mg, and the RV and the recombinant RV strain that harbored the intact (empty) plasmid pLP-1.2 (RVI) showed no detectable ACDH activity. The hydrogen yields of the RVAC strain from 21-mM acetate were 1.5-fold higher than that of the wild type RV strain and also that of the RVI strain. In contrast, hydrogen yield from 21-mM lactate was 30% lower than that in the control strains.
Development of oligomannose-coated liposome-based nasal vaccine against human parainfluenza virus type 3
Hideki Hasegawa,Hirokazu Kimura,Akihide Ryo
Frontiers in Microbiology , 2013, DOI: 10.3389/fmicb.2013.00346
Abstract: Human parainfluenza viruses (HPIVs) are the etiologic agents of lower respiratory infections and pneumonia in infants, young children and immunocompromised hosts. The overarching goal for the prevention of HPIV infection is the development of an effective vaccine against HPIVs. In the present study, we investigated the effectiveness of oligomannose-coated liposomes (OMLs) as an antigen-delivery system in combination with a synthetic double-stranded RNA analog for the induction of mucosal and systematic immunity against HPIV3. Full-length hemagglutinin-neuraminidase (HN) protein was synthesized using the wheat germ cell-free protein production system and then encapsulated into OML to serve as the antigen. Intranasal administration of the HN-filling OML (OML-HN) with the synthetic double-stranded RNA adjuvant, polyriboinosinic-polyribocytidylic acid [poly(I:C)] generated significant viral-specific systemic and mucosal immune responses as evidenced by the prominent induction of serum IgG and nasal wash IgA, respectively. On the other hand, no significant immune responses were observed in mice immunized with OML-HN without the adjuvant. Furthermore, serum from mice immunized with OML-HN plus poly(I:C) significantly suppressed viral infection in cell culture model. Our results provide the first evidence that intranasal co-administration of OML-encapsulated HN with the poly(I:C) adjuvant augments the viral-specific immunity against HPIV3.
Influence of surface states and bulk traps on non-equilibrium phenomena at GaAs and GaN surfaces
Marcin MICZEK,Boguslawa ADAMOWICZ,Tamotsu HASHIZUME,Hideki HASEGAWA
Optica Applicata , 2005,
Abstract: The influence of surface state density NSS and bulk non-radiative lifetime t on room temperature photoluminescence quantum efficiency YPL and surface photovoltage (SPV) versus the excitation light intensity F was studied theoretically for GaAs and wurtzite GaN using self-consistent computer simulations. It was demonstrated that SPV(F ) dependences are more sensitive than YPL(F ) to a change in magnitude of NSS, especially for high NSS and at low F, whereas SPV is practically insensitive to t contrary to YPL. The simultaneous measurement of YPL and SPV versus F, combined with rigorous computer analysis, seems to be a very promising method for contactless characterization of the surface and bulk trap parameters.
How much security does Y-00 protocol provide us ?
Tsuyoshi Nishioka,Toshio Hasegawa,Hirokazu Ishizuka,Kentaro Imafuku,Hideki Imai
Physics , 2003, DOI: 10.1016/j.physleta.2004.04.083
Abstract: New quantum cryptography, often called Y-00 protocol, has much higher performance than the conventional quantum cryptographies. It seems that the conventional quantum cryptographic attacks are inefficient at Y-00 protocol as its security is based on the different grounds from that of the conventional ones. We have, then, tried to cryptoanalyze Y-00 protocol in the view of cryptographic communication system. As a result, it turns out that the security of Y-00 protocol is equivalent to that of classical stream cipher.
Outer Membrane Vesicles of Porphyromonas gingivalis Elicit a Mucosal Immune Response
Ryoma Nakao, Hideki Hasegawa, Kuniyasu Ochiai, Shogo Takashiba, Akira Ainai, Makoto Ohnishi, Haruo Watanabe, Hidenobu Senpuku
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026163
Abstract: We previously reported that mutation of galE in Porphyromonas gingivalis has pleiotropic effects, including a truncated lipopolysaccharide (LPS) O-antigen and deglycosylation of the outer membrane protein OMP85 homolog. In the present study, further analysis of the galE mutant revealed that it produced little or no outer membrane vesicles (OMVs). Using three mouse antisera raised against whole cells of the P. gingivalis wild type strain, we performed ELISAs to examine the reactivity of these antisera with whole cells of the wild type or the galE mutant. All three antisera had significantly lower reactivity against the galE mutant compared to wild type. OMVs, but not LPS, retained the immunodominant determinant of P. gingivalis, as determined by ELISAs (with wild type LPS or OMVs as antigen) and absorption assays. In addition, we assessed the capacity of OMVs as a vaccine antigen by intranasal immunization to BALB/c mice. Synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid [Poly (I:C)], an agonist of Toll-like receptor 3 (TLR3), was used as the mucosal adjuvant. Vaccination with OMV elicited dramatically high levels of P. gingivalis-specific IgA in nasal washes and saliva, as well as serum IgG and IgA. In conclusion, the OMVs of P. gingivalis have an important role in mucosal immunogenicity as well as in antigenicity. We propose that P. gingivalis OMV is an intriguing immunogen for development of a periodontal disease vaccine.
Highly Frequent Mutations in Negative Regulators of Multiple Virulence Genes in Group A Streptococcal Toxic Shock Syndrome Isolates
Tadayoshi Ikebe ,Manabu Ato,Takayuki Matsumura,Hideki Hasegawa,Tetsutaro Sata,Kazuo Kobayashi,Haruo Watanabe
PLOS Pathogens , 2010, DOI: 10.1371/journal.ppat.1000832
Abstract: Streptococcal toxic shock syndrome (STSS) is a severe invasive infection characterized by the sudden onset of shock and multiorgan failure; it has a high mortality rate. Although a number of studies have attempted to determine the crucial factors behind the onset of STSS, the responsible genes in group A Streptococcus have not been clarified. We previously reported that mutations of csrS/csrR genes, a two-component negative regulator system for multiple virulence genes of Streptococcus pyogenes, are found among the isolates from STSS patients. In the present study, mutations of another negative regulator, rgg, were also found in clinical isolates of STSS patients. The rgg mutants from STSS clinical isolates enhanced lethality and impaired various organs in the mouse models, similar to the csrS mutants, and precluded their being killed by human neutrophils, mainly due to an overproduction of SLO. When we assessed the mutation frequency of csrS, csrR, and rgg genes among S. pyogenes isolates from STSS (164 isolates) and non-invasive infections (59 isolates), 57.3% of the STSS isolates had mutations of one or more genes among three genes, while isolates from patients with non-invasive disease had significantly fewer mutations in these genes (1.7%). The results of the present study suggest that mutations in the negative regulators csrS/csrR and rgg of S. pyogenes are crucial factors in the pathogenesis of STSS, as they lead to the overproduction of multiple virulence factors.
Development of mucosal adjuvants for intranasal vaccine for H5N1 influenza viruses
Hideki Hasegawa, Takeshi Ichinohe, Akira Ainai, Shin-ichi Tamura, Takeshi Kurata
Therapeutics and Clinical Risk Management , 2009, DOI: http://dx.doi.org/10.2147/TCRM.S3297
Abstract: pment of mucosal adjuvants for intranasal vaccine for H5N1 influenza viruses Review (12604) Total Article Views Authors: Hideki Hasegawa, Takeshi Ichinohe, Akira Ainai, Shin-ichi Tamura, Takeshi Kurata Published Date March 2009 Volume 2009:5 Pages 125 - 132 DOI: http://dx.doi.org/10.2147/TCRM.S3297 Hideki Hasegawa, Takeshi Ichinohe, Akira Ainai, Shin-ichi Tamura, Takeshi Kurata Laboratory of Infectious Disease Pathology, Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan Abstract: An increasing number of infections of highly pathogenic avian influenza virus (H5N1) in humans has been reported in South-East Asia and other areas of the world. High mortality (>60%) of this viral infection and its pathosis of systemic infection are features of this new human disease. Moreover, there is great concern that this avian H5N1 virus could cause a pandemic of new influenza in humans, once it acquires the ability for human to human transmission. To prevent such highly contagious infectious diseases as influenza, it is essential to prepare effective vaccines. Especially in the case of new influenza virus, we cannot predict the strain which will cause the pandemic. In such a situation, a vaccine that induces cross-protective immunity against variant viruses is extremely important. However currently used parenteral seasonal influenza vaccine is strain-specific, and is less effective against variant viruses. In order to overcome the weakness of current vaccines we need to learn from the immune responses induced by natural infection with influenza viruses. In the case of mucosally acquired acute respiratory infection such as influenza, mucosal immunity induced by natural infection plays important role in protection against the infection, as mucosal secretory IgA antibody plays an important role in cross-protection. In this review we describe the advantages and development of mucosal vaccine against highly pathogenic H5N1 influenza viruses.
Dynamic Effect of Low-Cost Entry on the Conduct Parameter: An Early-Stage Analysis of Southwest Airlines and America West Airlines  [PDF]
Hideki Murakami
Modern Economy (ME) , 2013, DOI: 10.4236/me.2013.44032
Abstract:

The purpose of this research is to investigate the dynamic changes in the competition between air carriers by applying a revised conduct parameter method. We examine the cases of Southwest Airlines and America West Airlines due to the availability of data. Our interests are in what fashion a low-cost carrier entered the market, how the rival reacted, and whether the fashions of competition between two types of air carrier remained stable as time passed. Our empirical results show that the fashions of competition fell between Cournot and “P = MC” competition, and competitive fashions were sometimes stable but sometimes not.

Efficient Frontier via Production Functions and Mechanization  [PDF]
Hideki Nakamura
American Journal of Operations Research (AJOR) , 2017, DOI: 10.4236/ajor.2017.71004
Abstract: This study attempts to reconcile data envelopment analysis (DEA) with the production function approach in economics. We examine not only the inputs of capital and labor, but also the ranges of these inputs in production process steps, and endogenously derive a Leontief production function. The Leontief production functions shift northeasterly owing to mechanization, which is the replacement of labor inputs by capital inputs in some steps. Consequently, we describe the efficient frontier as the convex hull of the Leontief production functions. Furthermore, we consider the possibility of efficient production below the efficient frontier.
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