Osaka, Japan
Osaka, Japan

Soai University is a private university in the city of Osaka, Japan. It was established in 1888, initially as a women's university. Famous people with ties to Soai include alumni Hideo Ishikawa, Haruko Okamoto, Mihoko Shuku, and Yasuhito Sugiyama. Wikipedia.

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Kawase S.,Soai University
Attention, Perception, and Psychophysics | Year: 2014

This study was designed to investigate the roles of gazing behavior during piano duo performance by highlighting coordination among performers. Experiment 1 was conducted under four conditions: invisible, only the body visible, only the head visible, and face -to -face. Experiment 2 was conducted under three conditions: invisible, only the movable head visible, and only the fixed head visible. In both experiments, performers looked toward each other just before temporal changes during coordination moments, which improved synchronization accuracy. The results also showed that gazing without movement cues to some extent facilitated synchronization, although asynchrony was greater under the restricted- movement condition than under the free- movement condition. The following results were obtained:(1) Mutual gaze is important for reducing timing lag between performers. (2) Mutual gaze modulates remarkable and arbitrary temporal expressions, such as fermata. (3) Performers may utilize movements as visual cues for strict synchronization. © 2013 Psychonomic Society, Inc.

Yasuda K.,Toyama Prefectural University | Ikushiro S.,Toyama Prefectural University | Wakayama S.,Showa Pharmaceutical University | Itoh T.,Showa Pharmaceutical University | And 5 more authors.
Drug Metabolism and Disposition | Year: 2012

Sesamin and episesamin are two epimeric lignans that are found in refined sesame oil. Commercially available sesamin supplements contain both sesamin and episesamin at an approximate 1:1 ratio. Our previous study clarified the sequential metabolism of sesamin by cytochrome P450 (P450) and UDP-glucuronosyltransferase in human liver. In addition, we revealed that sesamin caused a mechanism-based inhibition (MBI) of CYP2C9, the P450 enzyme responsible for sesamin monocatecholization. In the present study, we compared the metabolism and the MBI of episesamin with those of sesamin. Episesamin was first metabolized to the two epimers of monocatechol, S- and R-monocatechols in human liver microsomes. The P450 enzymes responsible for S- and R-monocatechol formation were CYP2C9 and CYP1A2, respectively. The contribution of CYP2C9 was much larger than that of CYP1A2 in sesamin metabolism, whereas the contribution of CYP2C9 was almost equal to that of CYP1A2 in episesamin metabolism. Docking of episesamin to the active site of CYP1A2 explained the stereoselectivity in CYP1A2-dependent episesamin monocatecholization. Similar to sesamin, the episesamin S- and R-monocatechols were further metabolized to dicatechol, glucuronide, and methylate metabolites in human liver; however, the contribution of each reaction was significantly different between sesamin and episesamin. The liver microsomes from CYP2C19 ultra-rapid metabolizers showed a significant amount of episesamin dicatechol. In this study, we have revealed significantly different metabolism by P450, UDP-glucuronosyltransferase, and catechol-O-methyltransferase for sesamin and episesamin, resulting in different biological effects. Copyright © 2012 by The American Society for Pharmacology and Experimental Therapeutics.

Yasuda K.,Toyama Prefectural University | Ikushiro S.,Toyama Prefectural University | Kamakura M.,Toyama Prefectural University | Ohta M.,Soai University | Sakaki T.,Toyama Prefectural University
Drug Metabolism and Disposition | Year: 2010

Metabolism of sesamin by cytochrome P450 (P450) was examined using yeast expression system and human liver microsomes. Saccharomyces cerevisiae cells expressing each of human P450 isoforms (CYP1A1, 1A2, 2A6, 2B6, 2C8, 2C9, 2C18, 2C19, 2D6, 2E1, and 3A4) were cultivated with sesamin, and monocatechol metabolite was observed in most of P450s. Kinetic analysis using the microsomal fractions of the recombinant S. cerevisiae cells revealed that CYP2C19 had the largest k cat/K m value. Based on the kinetic data and average contents of the P450 isoforms in the human liver, the putative contribution of P450s for sesamin metabolism was large in the order of CYP2C9, 1A2, 2C19, and 2D6. A good correlation was observed between sesamin catecholization activity and CYP2C9-specific activity in in vitro studies using 10 individual human liver microsomes, strongly suggesting that CYP2C9 is the most important P450 isoform for sesamin catecholization in human liver. Inhibition studies using each anti-P450 isoform-specific antibody confirmed that CYP2C9 was the most important, and the secondary most important P450 was CYP1A2. We also examined the inhibitory effect of sesamin for P450 isoform-specific activities and found a mechanism-based inhibition of CYP2C9 by sesamin. In contrast, no mechanism-based inhibition by sesamin was observed in CYP1A2-specific activity. Our findings strongly suggest that further studies are needed to reveal the interaction between sesamin and therapeutic drugs mainly metabolized by CYP2C9. Copyright © 2010 by The American Society for Pharmacology and Experimental Therapeutics.

Yasuda K.,Toyama Prefectural University | Ikushiro S.,Toyama Prefectural University | Kamakura M.,Toyama Prefectural University | Munetsuna E.,Toyama Prefectural University | And 2 more authors.
Drug Metabolism and Disposition | Year: 2011

Our previous study revealed that CYP2C9 played a central role in sesamin monocatecholization. In this study, we focused on the metabolism of sesamin monocatechol that was further converted into the dicatechol form by cytochrome P450 (P450) or the glucuronide by UDP-glucuronosyltransferase (UGT). Catecholization of sesamin monocatechol enhances its antioxidant activity, whereas glucuronidation strongly reduces its antioxidant activity. In human liver microsomes, the glucuronidation activity was much higher than the catecholization activity toward sesamin monocatechol. In contrast, in rat liver microsomes, catecholization is predominant over glucuronidation. In addition, rat liver produced two isomers of the glucuronide, whereas human liver produced only one glucuronide. These results suggest a significant species-based difference in the metabolism of sesamin between humans and rats. Kinetic studies using recombinant human UGT isoforms identified UGT2B7 as the most important UGT isoform for glucuronidation of sesamin monocatechol. In addition, a good correlation was observed between the glucuronidation activity and UGT2B7-specific activity in in vitro studies using 10 individual human liver microsomes. These results strongly suggest that UGT2B7 plays an important role in glucuronidation of sesamin monocatechol. Interindividual difference among the 10 human liver microsomes is approximately 2-fold. These results, together with our previous results on the metabolism of sesamin by human P450, suggest a small interindividual difference in sesamin metabolism. We observed the methylation activity toward sesamin monocatechol by catechol O-methyl transferase (COMT) in human liver cytosol. On the basis of these results, we concluded that CYP2C9, UGT2B7, and COMT played essential roles in the metabolism of sesamin in the human liver. Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics.

PubMed | University of Electro - Communications and Soai University
Type: | Journal: Consciousness and cognition | Year: 2016

Visual information has been observed to be crucial for audience members during musical performances. The present study used an eye tracker to investigate audience members gazes while appreciating an audiovisual musical ensemble performance, based on evidence of the dominance of musical part in auditory attention when listening to multipart music that contains different melody lines and the joint-attention theory of gaze. We presented singing performances, by a female duo. The main findings were as follows: (1) the melody part (soprano) attracted more visual attention than the accompaniment part (alto) throughout the piece, (2) joint attention emerged when the singers shifted their gazes toward their co-performer, suggesting that inter-performer gazing interactions that play a spotlight role mediated performer-audience visual interaction, and (3) musical part (melody or accompaniment) strongly influenced the total duration of gazes among audiences, while the spotlight effect of gaze was limited to just after the singers gaze shifts.

Endo-Umeda K.,Nihon University | Yasuda K.,Toyama Prefectural University | Sugita K.,University of Tokyo | Honda A.,Tokyo Medical University | And 5 more authors.
Journal of Steroid Biochemistry and Molecular Biology | Year: 2014

7-Dehydrocholesterol (7-DHC) is a common precursor of vitamin D3 and cholesterol. Although various oxysterols, oxygenated cholesterol derivatives, have been implicated in cellular signaling pathways, 7-DHC metabolism and potential functions of its metabolites remain poorly understood. We examined 7-DHC metabolism by various P450 enzymes and detected three metabolites produced by sterol 27-hydroxylase (CYP27A1) using high-performance liquid chromatography. Two were further identified as 25-hydroxy-7-DHC and 26/27-hydroxy-7-DHC. These 7-DHC metabolites were detected in serum of a patient with Smith-Lemli-Opitz syndrome. Luciferase reporter assays showed that 25-hydroxy-7-DHC activates liver X receptor (LXR) α, LXRβ and vitamin D receptor and that 26/27-hydroxy-7-DHC induces activation of LXRα and LXRβ, although the activities of both compounds on LXRs were weak. In a mammalian two-hybrid assay, 25-hydroxy-7-DHC and 26/27-hydroxy-7-DHC induced interaction between LXRα and a coactivator fragment less efficiently than a natural LXR agonist, 22(R)-hydroxycholesterol. These 7-DHC metabolites did not oppose agonist-induced LXR activation and interacted directly to LXRα in a manner distinct from a potent agonist. These findings indicate that the 7-DHC metabolites are partial LXR activators. Interestingly, 25-hydroxy-7-DHC and 26/27-hydroxy-7-DHC suppressed mRNA expression of sterol regulatory element-binding protein 1c, an LXR target gene, in HepG2 cells and HaCaT cells, while they weakly increased mRNA levels of ATP-binding cassette transporter A1, another LXR target, in HaCaT cells. Thus, 7-DHC is catabolized by CYP27A1 to metabolites that act as selective LXR modulators. © 2013 Elsevier Ltd. All rights reserved.

Yasuda K.,Toyama Prefectural University | Ikushiro S.,Toyama Prefectural University | Kamakura M.,Toyama Prefectural University | Takano M.,Teikyo University | And 5 more authors.
Journal of Steroid Biochemistry and Molecular Biology | Year: 2013

Our previous studies revealed that C2α-substituted-1α,25(OH) 2D3 analogs had unique biological activities. For example, 19-nor-2α-(3-hydroxypropyl)-1α,25(OH)2D3 (MART-10), which has a high affinity for vitamin D receptor (VDR), is more bioavailable and more potent than 1α,25(OH)2D3 in inhibiting cancer cell growth and invasion because of its weaker binding to vitamin D binding protein (DBP), and more resistance to CYP24A1-dependent metabolism. In this study, we examined the metabolism of MART-10 and two other 2α-substituted analogs, 2α-(3-hydroxypropoxy)-1α,25(OH) 2D3 (O2C3) and 2α-(3-hydroxypropyl)-1α,25(OH) 2D3 (O1C3) by using human liver microsomes and human P450s. We demonstrated that O2C3 was converted to 1α,2α,25(OH) 3D3 in human liver microsomes, whereas both O1C3 and MART-10 were hardly metabolized. The metabolism of O2C3 was significantly inhibited by ketoconazole, and the recombinant human CYP3A4 converted O2C3 to 1α,2α,25(OH)3D3, which suggests that CYP3A4 is responsible for the metabolism of O2C3 in human liver. The k cat/Km values of CYP3A4 for O1C3 and MART-10 are much smaller than that for O2C3. The kcat/Km values of human CYP24A1 for the three analogs are 1% (MART-10), 3% (O2C3), and 4% (O1C3) of that for 1α,25(OH)2D3, indicating that MART-10 is the most resistant to CYP24A1 hydroxylation. On the other hand, 1α,2α, 25(OH)3D3, the metabolite of O2C3 by CYP3A4, was metabolized by CYP24A1 via multiple pathways similar to 1α,25(OH) 2D3, which suggests that O2C3 can be metabolized by two sequential hydroxylations, first by CYP3A4 and then by CYP24A1 in human body. These results suggest that modification at C-2α position and C-19 demethylenation markedly change metabolic profiles and biological activities of vitamin D analogs. © 2012 Elsevier Ltd. All rights reserved.

Yasuda K.,Toyama Prefectural University | Endo M.,Toyama Prefectural University | Ikushiro S.,Toyama Prefectural University | Kamakura M.,Toyama Prefectural University | And 2 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

CYP2R1 is known to be a physiologically important vitamin D 25-hydroxylase. We have successfully expressed human CYP2R1 in Saccharomyces cerevisiae to reveal its enzymatic properties. In this study, we examined production of 25-hydroxylated vitamin D using whole recombinant yeast cells that expressed CYP2R1. When vitamin D3 or vitamin D2 was added to the cell suspension of CYP2R1-expressing yeast cells in a buffer containing glucose and β-cyclodextrin, the vitamins were converted into their 25-hydroxylated products. Next, we irradiated the cell suspension with UVB and incubated at 37°C. Surprisingly, the 25-hydroxy vitamin D2 was produced without additional vitamin D2. Endogenous ergosterol was likely converted into vitamin D2 by UV irradiation and thermal isomerization, and then the resulting vitamin D2 was converted to 25-hydroxyvitamin D2 by CYP2R1. This novel method for producing 25-hydroxyvitamin D2 without a substrate could be useful for practical purposes. © 2013 Elsevier Inc.

Kawase S.,Soai University
Ecological Psychology | Year: 2014

This study investigated modulation of gaze and synchronization in piano duos under manipulation of the leader-follower relationship. Three pairs of pianists played under 3 conditions: reversed leader/follower roles and one where neither was leader or follower. The primo and second players could see one another through a glass window but could hear only the sounds of the pianos. We analyzed each performer's gaze toward the coperformer frame by frame and measured asynchrony between performers. The main findings are that (a) gaze was altered in the presence of leadership assignments-followers' and leaders' gaze durations lengthened and shortened, respectively; (b) mutual gaze just before tempo changes enhanced synchronization regardless of leadership condition; and (c) the asynchronies of tone onset at the moment of a tempo change under the leader/follower conditions did not significantly differ from that under the control condition. Copyright Taylor & Francis.

PubMed | Toyama Prefectural University, Kyoto University and Soai University
Type: Journal Article | Journal: Biochemical and biophysical research communications | Year: 2016

Our previous studies revealed that the double variants of CYP105A1- R73A/R84A and R73V/R84A-show high levels of activity with respect to conversion of vitamin D3 to its biologically active form, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). In this study, we found that both the double variants were also capable of converting vitamin D2 to its active form, that is, 1,25-dihydroxyvitamin D2 (1,25(OH)2D2), via 25(OH)D2, whereas its 1-hydroxylation activity toward 25(OH)D2 was much lower than that toward 25(OH)D3. Comparison of the wild type and the double variants revealed that the amino acid substitutions remarkably enhanced both 25- and 26-hydroxylation activity toward vitamin D2. After 25-hydroxylation of vitamin D2, further hydroxylation at C26 may occur frequently without the release of 25(OH)D2 from the substrate-binding pocket. Thus, the double variants of CYP105A1 are quite useful to produce 25,26(OH)2D2 that is one of the metabolites of vitamin D2 detected in human serum.

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