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Search Results: 1 - 10 of 2645 matches for " Kenji Kawano "
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Role of Temporal Processing Stages by Inferior Temporal Neurons in Facial Recognition
Yasuko Sugase-Miyamoto,Kenji Kawano
Frontiers in Psychology , 2011, DOI: 10.3389/fpsyg.2011.00141
Abstract: In this review, we focus on the role of temporal stages of encoded facial information in the visual system, which might enable the efficient determination of species, identity, and expression. Facial recognition is an important function of our brain and is known to be processed in the ventral visual pathway, where visual signals are processed through areas V1, V2, V4, and the inferior temporal (IT) cortex. In the IT cortex, neurons show selective responses to complex visual images such as faces, and at each stage along the pathway the stimulus selectivity of the neural responses becomes sharper, particularly in the later portion of the responses. In the IT cortex of the monkey, facial information is represented by different temporal stages of neural responses, as shown in our previous study: the initial transient response of face-responsive neurons represents information about global categories, i.e., human vs. monkey vs. simple shapes, whilst the later portion of these responses represents information about detailed facial categories, i.e., expression and/or identity. This suggests that the temporal stages of the neuronal firing pattern play an important role in the coding of visual stimuli, including faces. This type of coding may be a plausible mechanism underlying the temporal dynamics of recognition, including the process of detection/categorization followed by the identification of objects. Recent single-unit studies in monkeys have also provided evidence consistent with the important role of the temporal stages of encoded facial information. For example, view-invariant facial identity information is represented in the response at a later period within a region of face-selective neurons. Consistent with these findings, temporally modulated neural activity has also been observed in human studies. These results suggest a close correlation between the temporal processing stages of facial information by IT neurons and the temporal dynamics of face recognition.
Visceral Fat Accumulation Is Associated with Increased Mortality Rate after Transcatheter Arterial Chemoembolization in Patients with Hepatocellular Carcinoma  [PDF]
Masaya Saito, Yoshihiko Yano, Hirotaka Hirano, Kenji Momose, Yuki Kawano, Masaru Yoshida, Takeshi Azuma
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.613122
Abstract: Aim: Transcatheter arterial chemoembolization (TACE) is thought to be a safe and effective treatment for hepatocellular carcinoma (HCC). However, in some HCC patients, it potentially shortens survival due to liver damage. We aimed to identify independent factors to predict overall survival of HCC after TACE. Methods: We included a total of 96 consecutive HCC patients who underwent TACE at Kobe University Hospital. Areas of skeletal muscle and fat tissue were measured by computed tomography (CT) scan before TACE. We divided the patients into two groups in terms of the presence or absence of 1-year mortality after TACE. Factors associated with 1-year mortality after TACE were assessed by multivariate analyses, and the optimal cut-off values were evaluated using a propensity score. Results: Multivariate analyses showed that visceral fat accumulation on CT was an independent factor associated with 1-year mortality after TACE (p = 0.033). There were no differences in skeletal muscle area and subcutaneous and intermuscular fat area between the two groups. Cut-off values for visceral fat area associated with 1-year mortality after TACE were defined as 33.3 cm2/m2 for males and 24.4 cm2/m2 for females. Conclusions: High visceral fat area was a prognostic factor associated with increased mortality rate in HCC patients undergoing TACE. Using this value, 1-year mortality risk after TACE would be better estimated before the day TACE was performed.
Lipid Rafts: Keys to Sperm Maturation, Fertilization, and Early Embryogenesis
Natsuko Kawano,Kaoru Yoshida,Kenji Miyado,Manabu Yoshida
Journal of Lipids , 2011, DOI: 10.1155/2011/264706
Abstract: Cell membranes are composed of many different lipids and protein receptors, which are important for regulating intracellular functions and cell signaling. To orchestrate these activities, the cell membrane is compartmentalized into microdomains that are stably or transiently formed. These compartments are called “lipid rafts”. In gamete cells that lack gene transcription, distribution of lipids and proteins on these lipid rafts is focused during changes in their structure and functions such as starting flagella movement and membrane fusion. In this paper, we describe the role of lipid rafts in gamete maturation, fertilization, and early embryogenesis. 1. Introduction Fertilization is the process in which 2 different gamete cells, a sperm and an oocyte, unite to produce a zygote. For fertilization to be successful, these gamete cells must differentiate and activate specific signaling pathways. For example, after sperm has differentiated completely, various extracellular factors such as epididymosomes and albumin alter the structure and function of the plasma membrane of the sperm. In addition, in terminally differentiated gamete cells, various sterols, sphingolipids, glycolipids, and glycosylphosphatidylinositol- (GPI-) anchored proteins are localized on cell membrane microdomains that are called lipid rafts. Lipid raft components are often examined by using detergent-resistant membrane domains (DRMs), which enrich these components so that their distributions and functions can be visualized on the cell surface by using putative raft markers [1, 2]. Since lipid rafts in gametes contain signaling proteins that regulate intracellular functions and cell signaling, these domains are important for sperm maturation, fertilization, and early embryogenesis [3, 4]. In this paper, we discuss the role of lipid rafts in reproductive biology. 2. Sperm Maturation and Membrane Modification Sperm are highly differentiated haploid cells with a head and a tail (flagellum) [5]. The head consists of a nucleus, an acrosome, and a small amount of cytoplasm, while the tail consists of a motility apparatus, mitochondria, an axoneme, and cytoskeletal structures. Although these structures are necessary for sperm to swim and fertilize oocytes, these structures are not functional after spermatogenesis until the plasma membrane is modified during epididymal transit (Figure 1(a)) [6]. In mammals, the sperm mature in the epididymis; however, in other animals, sperms mature in the spermiduct [7]. Previous studies have demonstrated that the modifications of the sperm plasma membrane that
Reattachment of the Osteotomized Greater Trochanter in Hip Surgery Using an Ultrahigh Molecular Weight Polyethylene Fiber Cable: A Multi-Institutional Study  [PDF]
Seiya Jingushi, Tsutomu Kawano, Hirokazu Iida, Kenichi Oe, Kenji Ohzono, Yoshihide Nakamura, Makoto Osaki, Hidetsugu Ohara, Seung Bak Lee, Toshihiko Hara, Naohide Tomita
Open Journal of Orthopedics (OJO) , 2013, DOI: 10.4236/ojo.2013.36052
Abstract:

The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery. Included in the study were 85 hips that had undergone surgery with greater trochanter osteotomy, including 50 hip arthroplasty procedures and 35 hip osteotomies. The osteotomized greater trochanter was reattached using one or more UHMWPE fiber cables. The bone union and displacement of the greater trochanter were assessed in radiographs for up to 12 months after surgery. Non-union of the osteotomy site occurred in 4.7% of the cases. In approximately 90% of the cases, displacement was less than 2 mm at up to 12 months after surgery. The UHMWPE fiber cable was a good biomaterial for reattaching the osteotomized greater trochanter and may also be an option for osteosynthesis procedures.

Developmentally-Regulated Excision of the SPβ Prophage Reconstitutes a Gene Required for Spore Envelope Maturation in Bacillus subtilis
Kimihiro Abe,Yuta Kawano,Keito Iwamoto,Kenji Arai,Yuki Maruyama,Patrick Eichenberger,Tsutomu Sato
PLOS Genetics , 2014, DOI: doi/10.1371/journal.pgen.1004636
Abstract: Temperate phages infect bacteria by injecting their DNA into bacterial cells, where it becomes incorporated into the host genome as a prophage. In the genome of Bacillus subtilis 168, an active prophage, SPβ, is inserted into a polysaccharide synthesis gene, spsM. Here, we show that a rearrangement occurs during sporulation to reconstitute a functional composite spsM gene by precise excision of SPβ from the chromosome. SPβ excision requires a putative site-specific recombinase, SprA, and an accessory protein, SprB. A minimized SPβ, where all the SPβ genes were deleted, except sprA and sprB, retained the SPβ excision activity during sporulation, demonstrating that sprA and sprB are necessary and sufficient for the excision. While expression of sprA was observed during vegetative growth, sprB was induced during sporulation and upon mitomycin C treatment, which triggers the phage lytic cycle. We also demonstrated that overexpression of sprB (but not of sprA) resulted in SPβ prophage excision without triggering the lytic cycle. These results suggest that sprB is the factor that controls the timing of phage excision. Furthermore, we provide evidence that spsM is essential for the addition of polysaccharides to the spore envelope. The presence of polysaccharides on the spore surface renders the spore hydrophilic in water. This property may be beneficial in allowing spores to disperse in natural environments via water flow. A similar rearrangement occurs in Bacillus amyloliquefaciens FZB42, where a SPβ-like element is excised during sporulation to reconstitute a polysaccharide synthesis gene, suggesting that this type of gene rearrangement is common in spore-forming bacteria because it can be spread by phage infection.
Dynamic Regulation of Myosin Light Chain Phosphorylation by Rho-kinase
Takako Kaneko-Kawano, Fugo Takasu, Honda Naoki, Yuichi Sakumura, Shin Ishii, Takahiro Ueba, Akinori Eiyama, Aiko Okada, Yoji Kawano, Kenji Suzuki
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039269
Abstract: Myosin light chain (MLC) phosphorylation plays important roles in various cellular functions such as cellular morphogenesis, motility, and smooth muscle contraction. MLC phosphorylation is determined by the balance between activities of Rho-associated kinase (Rho-kinase) and myosin phosphatase. An impaired balance between Rho-kinase and myosin phosphatase activities induces the abnormal sustained phosphorylation of MLC, which contributes to the pathogenesis of certain vascular diseases, such as vasospasm and hypertension. However, the dynamic principle of the system underlying the regulation of MLC phosphorylation remains to be clarified. Here, to elucidate this dynamic principle whereby Rho-kinase regulates MLC phosphorylation, we developed a mathematical model based on the behavior of thrombin-dependent MLC phosphorylation, which is regulated by the Rho-kinase signaling network. Through analyzing our mathematical model, we predict that MLC phosphorylation and myosin phosphatase activity exhibit bistability, and that a novel signaling pathway leading to the auto-activation of myosin phosphatase is required for the regulatory system of MLC phosphorylation. In addition, on the basis of experimental data, we propose that the auto-activation pathway of myosin phosphatase occurs in vivo. These results indicate that bistability of myosin phosphatase activity is responsible for the bistability of MLC phosphorylation, and the sustained phosphorylation of MLC is attributed to this feature of bistability.
Genomic Profiling of Oral Squamous Cell Carcinoma by Array-Based Comparative Genomic Hybridization
Shunichi Yoshioka, Yoshiyuki Tsukamoto, Naoki Hijiya, Chisato Nakada, Tomohisa Uchida, Keiko Matsuura, Ichiro Takeuchi, Masao Seto, Kenji Kawano, Masatsugu Moriyama
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056165
Abstract: We designed a study to investigate genetic relationships between primary tumors of oral squamous cell carcinoma (OSCC) and their lymph node metastases, and to identify genomic copy number aberrations (CNAs) related to lymph node metastasis. For this purpose, we collected a total of 42 tumor samples from 25 patients and analyzed their genomic profiles by array-based comparative genomic hybridization. We then compared the genetic profiles of metastatic primary tumors (MPTs) with their paired lymph node metastases (LNMs), and also those of LNMs with non-metastatic primary tumors (NMPTs). Firstly, we found that although there were some distinctive differences in the patterns of genomic profiles between MPTs and their paired LNMs, the paired samples shared similar genomic aberration patterns in each case. Unsupervised hierarchical clustering analysis grouped together 12 of the 15 MPT-LNM pairs. Furthermore, similarity scores between paired samples were significantly higher than those between non-paired samples. These results suggested that MPTs and their paired LNMs are composed predominantly of genetically clonal tumor cells, while minor populations with different CNAs may also exist in metastatic OSCCs. Secondly, to identify CNAs related to lymph node metastasis, we compared CNAs between grouped samples of MPTs and LNMs, but were unable to find any CNAs that were more common in LNMs. Finally, we hypothesized that subpopulations carrying metastasis-related CNAs might be present in both the MPT and LNM. Accordingly, we compared CNAs between NMPTs and LNMs, and found that gains of 7p, 8q and 17q were more common in the latter than in the former, suggesting that these CNAs may be involved in lymph node metastasis of OSCC. In conclusion, our data suggest that in OSCCs showing metastasis, the primary and metastatic tumors share similar genomic profiles, and that cells in the primary tumor may tend to metastasize after acquiring metastasis-associated CNAs.
Regras locais e a solu??o de problemas envolvendo geodésicas
Kawano, Alexandre;
Rem: Revista Escola de Minas , 2001, DOI: 10.1590/S0370-44672001000100007
Abstract: the problem of finding geodesics of a surface is a topic of differential geometry and tensor calculus. traditionally, by means of analytical manipulation, the problem originally put in terms of length of a line is restated into a set of coupled partial differential equations of difficult solution. complexity theory proposes the reverse way of viewing nature, first stating simple local rules that elementary agents must follow, and then from the interactions at the local level, to predict the behavior of the whole. in this paper a local rule based on the huygens principle is proposed that can be used to find geodesics of any surface. by using the rule, problems once considered difficult can be solved in an intuitive way.
Prion-derived copper-binding peptide fragments catalyze the generation of superoxide anion in the presence of aromatic monoamines
Tomonori Kawano
International Journal of Biological Sciences , 2007,
Abstract: Objectives: Studies have proposed two opposing roles for copper-bound forms of prion protein (PrP) as an anti-oxidant supporting the neuronal functions and as a pro-oxidant leading to neurodegenerative process involving the generation of reactive oxygen species. The aim of this study is to test the hypothesis in which putative copper-binding peptides derived from PrP function as possible catalysts for monoamine-dependent conversion of hydrogen peroxide to superoxide in vitro. Materials and methods: Four peptides corresponding to the copper (II)-binding motifs in PrP were synthesized and used for analysis of peptide-catalyzed generation of superoxide in the presence of Cu (II) and other factors naturally present in the neuronal tissues. Results: Among the Cu-binding peptides tested, the amino acid sequence corresponding to the Cu-binding site in the helical region was shown to be the most active for superoxide generation in the presence of Cu(II), hydrogen peroxide and aromatic monoamines, known precursors or intermediates of neurotransmitters. Among monoamines tested, three compounds namely phenylethylamine, tyramine and benzylamine were shown to be good substrates for superoxide-generating reactions by the Cu-bound helical peptide. Conclusions: Possible roles for these reactions in development of prion disease were suggested.
Regras locais e a solu o de problemas envolvendo geodésicas
Kawano Alexandre
Rem: Revista Escola de Minas , 2001,
Abstract: O problema de se determinarem as geodésicas de uma superfície é um tópico da Geometria Diferencial e Cálculo Tensorial. Tradicionalmente, o problema, posto em termos do comprimento de uma linha, é colocado, por meio de manipula es analíticas, em forma de uma solu o de um sistema de equa es diferenciais parciais acopladas de difícil solu o. A Teoria da Complexidade prop e uma maneira inversa de se interpretar a natureza, primeiro modelando regras locais simples, que agentes elementares devem seguir, e, a partir das intera es entre eles, chegar ao comportamento do todo. Nesse trabalho, uma regra local baseada no Princípio de Huygens é proposta, e com ela é possível se acharem geodésicas de uma superfície. Usando essa regra, problemas considerados difíceis podem ser resolvidos de maneira intuitiva.
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