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Search Results: 1 - 10 of 1565 matches for " Takahiro Asakage "
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Frequent Copy Gain of the MET Gene in Hypopharyngeal and Laryngeal Cancer in the Japanese Population  [PDF]
Ken Akashi, Yasuhiro Ebihara, Go Omura, Yuki Saito, Masafumi Yoshida, Mizuo Ando, Takahiro Asakage, Tatsuya Yamasoba, Yoshinori Murakami
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.612119
Abstract: Molecular targeting therapy to specific genetic alterations has not been established in head and neck squamous cell carcinoma (HNSCC) except for cetuximab treatment. To characterize alterations of actionable oncogenes in HNSCC, we examined the gain of copy and mutation of the MET gene in 54 Japanese HNSCC. Copy gain of the MET was analyzed by droplet digital PCR (ddPCR) and quantitative real time PCR (qPCR) using 2 distinct fragments of the gene, and mutation was examined in exons 14 - 19 of MET by Sanger sequencing. Both ddPCR and qPCR showed significantly correlated results in copy number at two distinct fragments of the MET gene (R = 0.96 and R = 0.78), although ddPCR gave more significant and sensitive results. Copy gain of the MET was detected in 10 of 54 (19%) HNSCCs and more frequently observed in tumors of the hypopharynx (4 of 12; 33%) or larynx (5 of 13; 38%) than those of the oral cavity (1 of 21; 4%) or oropharynx (0 of 8; 0%), suggesting the existence of site-specific features in the oncogenic mechanisms of HNSCCs. Copy gain of the MET was also observed preferentially in older patients, although no correlation in other parameters, including clinical stages and overall or recurrence-free survival, was observed. On the other hand, of the two HNSCCs in which nucleotide substitution was detected, one was R1040Q in exon 15 with unknown function, and the other was a silent mutation in exon16. These results suggest that copy gain of the MET can provide an indicator for treatment with tyrosine kinase inhibitors for MET in a subset of hypopharyngeal or laryngeal cancer.
High Incidence of Null-Type Mutations of the TP53 Gene in Japanese Patients with Head and Neck Squamous Cell Carcinoma  [PDF]
Yasuhiro Ebihara, Miwako Iwai, Ken Akashi, Takeshi Ito, Go Omura, Yuki Saito, Masafumi Yoshida, Mizuo Ando, Takahiro Asakage, Tatsuya Yamasoba, Yoshinori Murakami
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.57075

Objective: Molecular targeting therapy has not been generally established in head and neck squamous cell carcinoma (HNSCC) except for cetuximab treatment for targeting epidermal growth factor receptor (EGFR). We analyzed alterations of the TP53, KRAS2, and EGFR genes in Japanese HNSCC to identify subpopulations of tumors potentially susceptible or not susceptible to specific therapy based on their genetic alterations. Materials and Methods: A total of 56 Japanese subjects were included in this study. Genomic DNA of exons 5 - 9 of the TP53, exons 1 and 2 of the KRAS2, exons 19 - 22 of the EGFR, and their flanking sequences were amplified by polymerase chain reaction (PCR) followed by direct sequencing. Splicing variants of EGFR were examined by reverse transcription (RT)-PCR. Results: Mutations of the TP53 and KRAS genes were detected in 25 (45%) and 2 (4%) of 56 HNSCC cases, respectively, while neither mutation nor splicing variant of EGFR was observed. The

A Case of Simultaneous Triple Primary Cancers of the Hypopharynx, Esophagus, and Stomach Which Were Dissected by Endoscopic Laryngo-Pharyngeal Surgery Combined with Endoscopic Submucosal Dissection  [PDF]
Kenro Kawada, Taro Sugimoto, Ryuhei Okada, Kazuya Yamaguchi, Yuudai Kawamura, Masafumi Okuda, Yuuichiro Kume, Andres Mora, Tairo Ryotokuji, Takuya Okada, Akihiro Hoshino, Yutaka Tokairin, Yasuaki Nakajima, Yusuke Kiyokawa, Fuminori Nomura, Yoshuke Ariizumi, Shohei Tomii, Takashi Ito, Takahiro Asakage, Yusuke Kinugasa, Tatsuyuki Kawano
Open Journal of Gastroenterology (OJGas) , 2018, DOI: 10.4236/ojgas.2018.83010
Abstract: A 65-year-old man was admitted to our hospital following 6 months of dysphagia. At first, conventional endoscopy showed a reddish and depressed lesion in the stomach and an elevated lesion in the posterior wall of the hypopharynx. An endoscopic biopsy showed adenocarcinoma in the stomach, and squamous cell carcinoma in the hypopharynx. On the further examination, trans-nasal endoscopy with narrow band imaging (NBI) was performed. During the trumpet maneuver, a huge protruded lesion was observed and it reached to the orifice of the esophagus. Other superficial lesion located at left pyriform sinus was detected by NBI system as brownish area with brown dots. Furthermore, superficial esophageal cancer in the cervical esophagus was detected. Finally, 4 carcinomas in upper gastrointestinal tract were detected. Among them, the hypopharyngeal cancer was the most advanced (T3N0). The patient hoped to preserve his voice and swallowing function, endoscopic laryngo-pharyngeal surgery (ELPS) was performed for the hypopharyngeal cancer. Endoscopic mucosal resection (EMR) was performed for the esophageal cancer, and Endoscopic submucosal dissection (ESD) was performed for the gastric cancer. Under collaboration between a head and neck surgeon and an endoscopist, the tumor was resected en-bloc. The histopathological findings of hypopharyngeal cancer were squamous cell carcinoma, subeipthelial invasion, 29 × 28 × 4.2 mm. The others were diagnosed as mucosal cancers. The patient is currently alive with no recurrence at 28 months after the surgery; there is no stricture at the cervical esophagus. Endoscopic laryngopharyngeal surgery for the tumor of pharyngo-esophageal junction can provide a less invasive treatment.
The genetic architecture of insecticide resistance within a natural population of Drosophila melanogaster  [PDF]
Takahiro Miyo
Open Journal of Genetics (OJGen) , 2012, DOI: 10.4236/ojgen.2012.22013
Abstract: The dynamics of genetic variation in susceptibility to insecticides within a natural population of Drosophila melanogaster (Meigen) at Katsunuma (Yamanashi Prefecture, Japan) was examined. Two resistance factors for three organophosphate insecticides (OPs), a resistant-type acetylcholinesterase (AChE) and a cytochrome P450 monooxygenase (cytochrome P450), have already been suggested to be involved within the Katsunuma population. In this study, genetic variances were estimated for susceptibility to other classes of chemicals than OPs, permethrin (a pyrethroid) and dichloro-diphenyl-trichloroethane (DDT; an organo-chlorine), which existed simultaneously with genetic variances for susceptibility to OPs. Analyses of variance for susceptibility to permethrin and DDT showed highly significant variation among isofemale lines from the Katsunuma population, and the genetic variances for susceptibility to each insecticide fluctuated differently during this period. The impacts of fluctuations of genetic variation in susceptibility to one class of insecticides on genetic variation in susceptibility to other classes of insecticides existing simultaneously within the natural population were discussed.
Is It Wrong to Apply the Intrinsic Rate of Natural Increase to Individuals and Compare It among Genotypes?  [PDF]
Takahiro Miyo
Open Journal of Genetics (OJGen) , 2018, DOI: 10.4236/ojgen.2018.81001
Abstract: In order to gain insights into the seasonal dynamics of genetic variation in insecticide resistance within a natural population of Drosophila melanogaster during population growth, which we considered the most important ecological factor there, we conducted a series of genetic analyses of resistance factors involved in that population and compared individual-based intrinsic rates of natural increase among resistance genotypes. However, some researchers have argued that it is a misconception to apply the intrinsic rate of natural increase to individuals, because it is a population parameter. We consider that their criticisms were incorrect. In this article, I described our research briefly and set forth the reasons why we conducted these studies.
Elevated Root-Zone Temperature Modulates Growth and Quality of Hydroponically Grown Carrots  [PDF]
Masaru Sakamoto, Takahiro Suzuki
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.68072
Abstract: Air and soil temperatures strongly influence the growth and quality of crops. However, in root vegetables, such as carrot, few experiments aimed at regulating growth and quality by manipulating root-zone temperature have been reported. We investigated the effect of root-zone temperatures (20°C, 25°C, 29°C, and 33°C) on carrot growth and components using a hydroponic system. High root-zone temperatures for 14 days reduced shoot and rootgrowth and water content. In contrast, total phenolic compounds and soluble-solid content increased in tap roots under high-temperature treatment. Root oxygen consumption was upregulated after 7 days under high-temperature treatment. These results suggest that high root-zone temperatures induce drought-like stress responses that modulate carrot biomass and components. High root-zone temperature treatments administered to hydroponically grown crops may be a valuable tool for improving and increasing the quality and value of crops.
Effect of Root-Zone Temperature on Growth and Quality of Hydroponically Grown Red Leaf Lettuce (Lactuca sativa L. cv. Red Wave)  [PDF]
Masaru Sakamoto, Takahiro Suzuki
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.614238
Abstract: Soil temperature influences crop growth and quality under field and greenhouse conditions; however, precise investigation using controlled cultivation systems is largely lacking. We investigated effects of root-zone temperatures on growth and components of hydroponically grown red leaf lettuce (Lactuca sativa L. cv. Red Wave) under a controlled cultivation system at 20°C. Compared with ambient root-zone temperature exposure, a 7-day low temperature exposure reduced leaf area, stem size, fresh weight, and water content of lettuce. However, root-zone heating treatments produced no significant changes in growth parameters compared with ambient conditions. Leaves under low root-zone temperature contained higher anthocyanin, phenols, sugar, and nitrate concentrations than leaves under other temperatures. Root oxygen consumption declined with low temperature root exposure, but not with root heating. Leaves of plants under low rootzone temperature showed hydrogen peroxide production, accompanied by lipid peroxidation. Therefore, low temperature root treatment is suggested to induce oxidative stress responses in leaves, activating antioxidative secondary metabolic pathways.
Synergistic Effects of a Night Temperature Shift and Methyl Jasmonate on the Production of Anthocyanin in Red Leaf Lettuce  [PDF]
Masaru Sakamoto, Takahiro Suzuki
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.87106
Abstract: The production of a secondary metabolite such as anthocyanin is coordinately regulated by plant intrinsic factors and influenced by multiple environmental factors. In red leaf lettuce, the red pigment component anthocyanin is important for the commercial value of the crop, but its synchronous regulation by multiple factors is not well understood. Here, we examined the synergistic effects of a night temperature shift and methyl jasmonate (MJ) on the production of anthocyanin in red leaf lettuce. Low or high night temperature treatment for 3 days just before harvesting induced the production of anthocyanin without affecting plant biomass. Temperature-dependent activation of anthocyanin accumulation was accelerated by treating with MJ. Night temperature shifts and MJ triggered oxidative stresses in leaves, as indicated by hydrogen peroxide accumulation and lipid peroxidation. Interestingly, these oxidative stresses were more evident in leaves simultaneously treated with both a high night temperature and MJ. The activity of the superoxide dismutase (SOD) was increased alongside the elevation of oxidative stress. Taken together, these results indicate that the combined treatment of a night temperature shift with MJ may accelerate anthocyanin production by increasing the levels of oxidative stress to the leaves of red leaf lettuce.
Construction of axisymmetric steady states of an inviscid incompressible fluid by spatially discretized equations for pseudo-advected vorticity
Takahiro Nishiyama
International Journal of Mathematics and Mathematical Sciences , 2005, DOI: 10.1155/ijmms.2005.3319
Abstract: An infinite number of generalized solutions to the stationary Euler equations with axisymmetry and prescribed circulation are constructed by applying the finite difference method for spatial variables to an equation of pseudo-advected vorticity. They are proved to be different from exact solutions which are written with trigonometric functions and a Coulomb wave function.
Duality of Variable Exponent Triebel-Lizorkin and Besov Spaces
Takahiro Noi
Journal of Function Spaces and Applications , 2012, DOI: 10.1155/2012/361807
Abstract: We will prove the duality and reflexivity of variable exponent Triebel-Lizorkin and Besov spaces. It was shown by many authors that variable exponent Triebel-Lizorkin spaces coincide with variable exponent Bessel potential spaces, Sobolev spaces, and Lebesgue spaces when appropriate indices are chosen. In consequence of the results, these variable exponent function spaces are shown to be reflexive.
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