Publications by authors named "Yasuhiro Sakamoto"

49 Publications

Phase II Study of the Reuse of Trastuzumab with Docetaxel beyond Progression after First-Line Treatment in Second-Line Treatment for Unresectable, Metastatic Gastric Cancer (T-CORE1203).

Tohoku J Exp Med 2021 05;254(1):49-55

Department of Medical Oncology, Tohoku University Hospital.

Whether trastuzumab use beyond disease progression is beneficial in second-line treatment for patients with unresectable human epidermal growth factor receptor 2 (HER2)-positive gastric cancer remains to be elucidated. We conducted this phase II study to assess whether trastuzumab plus docetaxel was effective for patients with previously treated advanced HER2-positive gastric cancer. This trial was a single-arm, open-label, multicenter, phase II study, conducted by Tohoku Clinical Oncology Research and Education Society (T-CORE). Patients aged 20 years or older who had advanced HER2-positive gastric cancer and were refractory to trastuzumab, fluoropyrimidine, and cisplatin were enrolled. Patients were treated with 6 mg/kg trastuzumab and 60 mg/m docetaxel every 3 weeks. The primary endpoint was the overall response rate. The threshold overall response rate was estimated to be at 15%. Secondary endpoints were progression-free survival, 6-month survival rate, overall survival, and toxicities. A total of 27 patients were enrolled from 7 hospitals. The median age was 67 years. Partial response was seen in 3 patients among the 26 evaluated patients. The overall response rate was at 11.5% (90% confidence interval 1.2%-21.8%). The median progression-free survival was 3.2 months, the 6-month survival rate was 85%, and the median overall survival was 11.6 months. Febrile neutropenia was observed in 14.8%. The most frequently observed grade 3 non-hematologic toxicity was anorexia (14.8%). The primary endpoint was not achieved. The results support a current consensus that the continuation of trastuzumab in second-line therapy for gastric cancer is not a recommended option.
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http://dx.doi.org/10.1620/tjem.254.49DOI Listing
May 2021

Phase II study of trifluridine/tipiracil (TAS-102) therapy in elderly patients with colorectal cancer (T-CORE1401): geriatric assessment tools and plasma drug concentrations as possible predictive biomarkers.

Cancer Chemother Pharmacol 2021 Sep 24;88(3):393-402. Epub 2021 May 24.

Department of Medical Oncology, Tohoku University Hospital, Seiryo-machi 1-1, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.

Purpose: The current study aimed to determine the efficacy of trifluridine/tipiracil for elderly patients with advanced colorectal cancer.

Methods: This single-arm, open-label, multicenter, phase II study included elderly patients aged 65 years or more who had fluoropyrimidine-refractory advanced colorectal cancer and received trifluridine/tipiracil (70 mg/m, days 1-5 and 8-12, every 4 weeks). The primary endpoint was progression-free survival (PFS), while secondary endpoints included overall survival (OS), overall response rate (ORR), toxicities, association between efficacy and geriatric assessment scores, and association between toxicity and plasma drug concentrations.

Results: A total of 30 patients with a mean age of 73 years were enrolled. Median PFS was 2.3 months (95% confidence interval, 1.9-4.3 months), while median OS was 5.7 months (95% confidence interval, 3.7-8.9 months). Patients had an ORR of 0%, with 57% having stable disease. Grade 4 neutropenia was observed in 13% of the patients. Patients with a higher G8 score (15 or more) showed longer PFS than those with a lower G8 score (median 4.6 vs. 2.0 months; p = 0.047). Moreover, patients with grade 3 or 4 neutropenia showed higher maximum trifluridine concentrations than those with grade 1 or 2 neutropenia (mean 2945 vs. 2107 ng/mL; p = 0.036).

Discussion: The current phase II trial demonstrated that trifluridine/tipiracil was an effective and well-tolerated option for elderly patients with advanced colorectal cancer. Moreover, geriatric assessment tools and/or plasma drug concentration monitoring might be helpful in predicting the efficacy and toxicities in elderly patients receiving this drug.

Trial Registration Number: UMIN000017589, 15/May/2015 (The University Hospital Medical Information Network).
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http://dx.doi.org/10.1007/s00280-021-04277-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8316169PMC
September 2021

Advanced colorectal cancer subtypes (aCRCS) help select oxaliplatin-based or irinotecan-based therapy for colorectal cancer.

Cancer Sci 2021 Apr 27;112(4):1567-1578. Epub 2021 Feb 27.

Department of Medical Oncology, Tohoku University Hospital, Miyagi, Japan.

Oxaliplatin (OX) and irinotecan (IRI) are used as key drugs for the first-line treatment of metastatic colorectal cancer (mCRC). However, no biomarkers have been identified to decide which of the drugs is initially used. In this translational research (TR) of the TRICOLORE trial, the advanced colorectal cancer subtype (aCRCS) was analyzed as a potential biomarker for the selection of OX or IRI. We collected 335 (68.8%) formalin-fixed, paraffin-embedded (FFPE) primary tumor specimens from 487 patients registered in the TRICOLORE trial and performed direct sequencing and immunohistochemical staining of CRC-related genes, comprehensive gene-expression analysis, and genome-wide methylation analysis. The progression-free survival (PFS) of the IRI group was significantly better compared with the OX group in BRAF wild-type (WT), PTEN-positive, and aCRCS A1 patients. Among the molecular factors, aCRCS were only associated with the PFS of OX and IRI groups. The PFS of the IRI group was significantly better compared with the OX group in aCRCS A1 + B1 (hazard ratio [HR] = 0.58; 95% confidence interval [CI] = 0.41-0.82; P = .0023). In contrast, the OX group had better PFS compared with the IRI group in aCRCS B2, although this was not statistically significant (HR = 1.66; 95% CI = 0.94-2.96; P = .083). Nearly half of patients with mCRC (46.8%, aCRCS A1 + B1) respond well to IRI, while only about 18.5% (aCRCS B2) of patients with mCRC responded well to OX. In conclusion, the aCRCS might be a predictive factor for the clinical outcomes of OX-based and IRI-based therapies.
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http://dx.doi.org/10.1111/cas.14841DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019218PMC
April 2021

A new microporous 12-ring zincosilicate THK-2 with many terminal silanols characterized by automated electron diffraction tomography.

Dalton Trans 2020 Oct 16;49(37):12960-12969. Epub 2020 Sep 16.

Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, 599-8531, Japan.

A newly synthesized microporous zincosilicate THK-2 (estimated structural composition: |(HO)(CHN)|[LiZnSiO(OH)]) was characterized by single-crystal electron diffraction using the automated electron diffraction tomography (ADT) approach in combination with powder X-ray diffraction. The lattice constants and space group of as-synthesized THK-2 were a = 2.50377(7) nm, b = 1.43866(4) nm, c = 0.505369(8) nm, and Pccn (no. 56) with orthorhombic symmetry. Because the crystal lattice was almost identical to a hexagonal lattice (), the first several peaks in its powder X-ray diffraction data severely overlapped, which suppressed the structural information to decide the framework topology. In order to overcome this intrinsic difficulty, the structure model of THK-2 was initially obtained by the direct method based on ADT data and refined by the Rietveld method. Its 3-dimensional framework structure was elucidated and it consisted of 4-, 5-, 6-rings of tetrahedral Si and Zn atoms and a one-dimensional straight channel with a 12-ring pore opening. Zn atoms were incorporated into the framework as four-coordinated [ZnO], although their distribution was confirmed to be disorderly. In the as-synthesized THK-2, the site occupancy of Zn was as low as 0.39; that is, more than 60% of the Zn sites were vacant. Hexamethyleneimine and water molecules were accommodated in the straight channel in a disordered manner. The material was stable upon calcination, and the BET specific surface area and micropore volume of calcined THK-2 were 240.6 m g and 0.12 ml g, respectively.
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http://dx.doi.org/10.1039/d0dt02290jDOI Listing
October 2020

Listening to birdsong reveals basic features of rate perception and aesthetic judgements.

Proc Biol Sci 2020 03 25;287(1923):20193010. Epub 2020 Mar 25.

Department of Neurosciences, Max Planck Institute for Empirical Aesthetics, Germany.

The timing of acoustic events is central to human speech and music. Tempo tends to be slower in aesthetic contexts: rates in poetic speech and music are slower than non-poetic, running speech. We tested whether a general preference for slower rates can account for this, using birdsong as a stimulus: it structurally resembles human sequences but is unbiased by their production or processing constraints. When listeners selected the birdsong playback tempo that was most pleasing, they showed no bias towards any range of note rates. However, upon hearing a novel stimulus, listeners rapidly formed a robust, implicit memory of its temporal properties, and developed a stimulus-specific preference for the memorized tempo. Interestingly, in birdsong stimuli was strongly determined by individual, internal preferences for rates of 1-2 Hz. This suggests that processing complex sound sequences relies on a default time window, while aesthetic appreciation appears flexible, experience-based and not determined by absolute event rates.
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http://dx.doi.org/10.1098/rspb.2019.3010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7126030PMC
March 2020

Development of Ion Mobility Spectrometry with Novel Atmospheric Electron Emission Ionization for Field Detection of Gaseous and Blister Chemical Warfare Agents.

Anal Chem 2019 04 28;91(8):5403-5414. Epub 2019 Mar 28.

RIKEN KEIKI Co., Ltd. , 2-7-6 Azusawa , Itabashi, Tokyo 174-8744 , Japan.

Drift tube ion mobility spectrometry with a novel atmospheric electron emission (AEE) source was developed for determination of gaseous and blister chemical warfare agents (CWAs) in negative mode. The AEE source was fabricated from an aluminum substrate electrode covered with 1 μm silver nanoparticle-dispersed silicone resin and a thin gold layer. This structure enabled stable tunneling electron emission upon the application of more than 11 V potential under atmospheric pressure. The reactant ion peak (RIP) was observed for the reduced mobility constant ( K) of 2.18 and optimized at the charging voltage of 20 V. This RIP was assigned to O by using a mass spectrometer. Hydrogen cyanide was detected as a peak ( K = 2.47) that was discriminatively separated from the RIP (resolution = 1.4), with a limit of detection (LOD) of 0.057 mg/m, and assigned to CN and OCN. Phosgene was detected as a peak ( K = 2.36; resolution = 1.2; and LOD = 0.6 mg/m), which was assigned to Cl. Lewisite 1 was detected as two peaks ( K = 1.68 and 1.34; LOD = 12 and 15 mg/m). The K = 1.68 peak was ascribed to a mixture of adducts of molecules or the product of hydrolysis with oxygen or chloride. Cyanogen chloride, chlorine, and sulfur mustard were also well detected. The detection performance with the AEE source was compared with those under corona discharge and Ni ionizations. The advantage of the AEE source is the simple RIP pattern (only O), and the characteristic marker ions contribute to the discriminative CWAs detection.
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http://dx.doi.org/10.1021/acs.analchem.9b00672DOI Listing
April 2019

Curved Fragmented Graphenic Hierarchical Architectures for Extraordinary Charging Capacities.

Small 2018 Jul 29;14(27):e1702054. Epub 2018 May 29.

Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan.

An approach to assemble hierarchically ordered 3D arrangements of curved graphenic nanofragments for energy storage devices is described. Assembling them into well-defined interconnected macroporous networks, followed by removal of the template, results in spherical macroporous, mesoporous, and microporous carbon microball (3MCM) architectures with controllable features spanning nanometer to micrometer length scales. These structures are ideal porous electrodes and can serve as lithium-ion battery (LIB) anodes as well as capacitive deionization (CDI) devices. The LIBs exhibit high reversible capacity (up to 1335 mAh g ), with great rate capability (248 mAh g at 20 C) and a long cycle life (60 cycles). For CDI, the curved graphenic networks have superior electrosorption capacity (i.e., 5.17 mg g in 0.5 × 10 m NaCl) over conventional carbon materials. The performance of these materials is attributed to the hierarchical structure of the graphenic electrode, which enables faster ion diffusion and low transport resistance.
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http://dx.doi.org/10.1002/smll.201702054DOI Listing
July 2018

Low Temperature Synthesized HTiO Nanotubes with a High CO Adsorption Property by Amine Modification.

Langmuir 2018 06 30;34(23):6814-6819. Epub 2018 May 30.

Division of Chemical Engineering, Graduate School of Engineering Science , Osaka University , 1-3 Machikaneyama , Toyonaka , Osaka 560-8531 , Japan.

Carbon dioxide (CO) capture and storage (CCS) technologies have been attracting attention in terms of tackling with global warming. To date, various CO capture technologies including solvents, membranes, cryogenics, and solid adsorbents have been proposed. Currently, a liquid adsorption method for CO using amine solution (monoethanolamine) has been practically used. However, this liquid phase CO adsorption process requires heat regeneration, and it can cause many problems such as corrosion of equipment and degradation of the solution. Meanwhile, solid adsorption methods using porous materials are more advantageous over the liquid method at these points. In this context, we here evaluated if hydrogen titanate (HTiO) nanotubes and the surface modification effectively capture CO. For this aim, we first developed a facile synthesis method of HTiO nanotubes different from any conventional methods. Briefly, they were converted from the precursors-amorphous TiO nanoparticles at room temperature (25 °C). We then determined the outer and the inner diameters of the HTiO nanotubes as 3.0 and 0.7 nm, respectively. It revealed that both values were much smaller than the reported ones; thus the specific surface area showed the highest value (735 m/g). Next, the outer surface of HTiO nanotubes was modified using ethylenediamine to examine if CO adsorption capacity increases. The ethylendiamine-modified HTiO nanotubes showed a higher CO adsorption capacity (50 cm/g at 0 °C, 100 kPa). We finally concluded that the higher CO adsorption capacity could be explained, not only by the high specific surface area of the nanotubes but also by tripartite hydrogen bonding interactions among amines, CO, and OH groups on the surface of HTiO.
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http://dx.doi.org/10.1021/acs.langmuir.8b00317DOI Listing
June 2018

Intermittent Withdrawal of Oxaliplatin for Alleviating Neurotoxicity during Oxaliplatin-Based Chemotherapy for Japanese Patients with Inoperable or Metastatic Colorectal Cancer: A Phase 2 Multicenter Study.

Tohoku J Exp Med 2018 05;245(1):21-28

Department of Medical Oncology, Tohoku University Hospital.

Oxaliplatin-based chemotherapy is a well-established regimen for patients with inoperable and metastatic colorectal cancer. However, one of the major limitations of oxaliplatin-based chemotherapy is sensory neuropathy. It was previously reported that introduction of intermittent oxaliplatin treatment to an oxaliplatin-based regimen has a significant benefit on efficacy or safety. Here, we prospectively assessed whether efficacy and safety of first-line chemotherapy for advanced colorectal cancer are achieved by introduction of withdrawal of oxaliplatin treatment for a certain period (intermittent oxaliplatin treatment). The primary endpoint of the present study is to assess the progression free survival time on patients treated with chemotherapy (mFOLFOX6 (levofolinate, 5-fluorouracil and oxaliplatin combination therapy) plus bevacizumab or CapeOX (oxaliplatin and capecitabine combination therapy) plus bevacizumab) with intermittent oxaliplatin treatment. Bevacizumab is a humanized anti-vascular endothelial growth factor antibody. Median progression-free survival by the mFOLFOX6 plus bevacizumab with intermittent oxaliplatin treatment or the CapeOX plus bevacizumab with intermittent oxaliplatin treatment were 10.6 months (95% confidential interval [CI], 8.3-13.4 months) or 8.0 months (95% CI, 4.2-16.8 months), respectively. Overall response rate by the mFOLFOX6 plus bevacizumab with intermittent oxaliplatin treatment or CapeOX plus bevacizumab with intermittent oxaliplatin treatment was 55.1% or 42.1%, respectively. Grade 3 or 4 neuropathy was observed in 4.1% or 10.5% of patients treated with mFOLFOX6 plus bevacizumab with intermittent oxaliplatin treatment or CapeOX plus bevacizumab with intermittent oxaliplatin treatment, respectively. Introduction of intermittent oxaliplatin treatment has improved severe neuropathy in mFOLFOX6 plus bevacizumab regimen without reducing treatment efficacy.
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http://dx.doi.org/10.1620/tjem.245.21DOI Listing
May 2018

Synthetic lethal interaction of CDK inhibition and autophagy inhibition in human solid cancer cell lines.

Oncol Rep 2017 Jul 30;38(1):31-42. Epub 2017 May 30.

Department of Clinical Oncology, IDAC, Tohoku University, Aoba-ku, Sendai 980-8575, Japan.

Cell cycle control is a promising target in cancer treatments, and some small-molecule cyclin-dependent kinase (CDK) inhibitors have exhibited clinical effectiveness. However, no biomarkers predictive of efficacy have been developed. Recent studies have revealed that CDK inhibitor (CKI) proteins, such as p27 and p16, also induced cytoprotective autophagy in cancer cells. However, it is unclear whether small-molecule CKIs also induce autophagy in solid tumors, as induced autophagy promotes cancer cell survival. In this study, we revealed that a CDK4 inhibitor and a CKI with a broad range of targets (flavopiridol) induced autophagy in some, but not all, solid cancer cell lines. Autophagy induction by CDK4 inhibitor was observed in BT474, MDA-MB435S, SKBr3 (derived from breast cancer), A431 (derived from epidermoid cancer), and SW480 (derived from colorectal cancer) cell lines. No such autophagy was observed in MCF7, MDA-MB231 (derived from breast cancer), NCI-N87 (derived from gastric cancer), and KMST-6 (derived from a fibroblast). In the cell lines showing autophagy, which was induced by CDK4 inhibitor, the combination of CDK4 inhibitor and autophagy inhibition by either chloroquine (CQ) or knockdown of ATG5 or BECN1 induced apoptosis. However, it did not induce apoptosis in the cell lines in which autophagy was not induced by CDK4 inhibitor. These findings indicate that the autophagy induced by CDK4 inhibitor mimics stress-induced autophagy in some solid cancer cell lines. The combination of a small-molecule CKI involved in G1/S arrest and an autophagy inhibitor leads to a synthetic lethal interaction and could become a new antitumor strategy for solid tumors showing cytoprotective autophagy induced by small-molecule CKIs.
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http://dx.doi.org/10.3892/or.2017.5684DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492844PMC
July 2017

Defect structures in Frank-Kasper type square-triangle tiling of multimodal cage-type mesoporous silicas.

J Phys Condens Matter 2017 Mar 20;29(12):124002. Epub 2017 Jan 20.

PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan. Department of Physics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.

Multimodal cage-type mesoporous silicas (MCMSs) with Frank-Kasper type square-triangle tiling show a unique defect structure, so-called three-fold symmetric hexagons, or shields, which are caused by phason fluctuations in dodecagonal quasicrystals. We observed and characterized three types of configurations inside shields in both quasiperiodic and periodic 3.4.3.4 tiling of MCMSs by transmission electron microscopy (TEM). The high-resolution TEM images of the shields were well explained by polyhedral models, which are the constituents of the Frank-Kasper type tetrahedrally close-packed structures of MCMSs. Shield defects invariably formed because of mismatch in periodic and/or aperiodic square-triangle tiling, and they were also catalyzed by other defects. Multiple shields overlapped with sharing of 30° rhombus units and showed characteristic motifs in the tiling, such as defect-mediated 12-fold wheel and stripe bundle arrangements. Hence, MCMSs with square-triangle tiling would be governed by a random-tiling-like structure stabilized by entropy rather than energy, which results in defect-free tiling.
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http://dx.doi.org/10.1088/1361-648X/aa5b02DOI Listing
March 2017

A Mesoporous Superlattice Consisting of Alternately Stacking Interstitial Nanospace within Binary Silica Colloidal Crystals.

Angew Chem Int Ed Engl 2016 08 28;55(36):10702-6. Epub 2016 Jul 28.

Department of Applied Chemistry, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169-8555, Japan.

A novel class of nonclassical structures of mesoporous silica, namely a binary nanoparticle mesoporous superlattice (BNMS), is obtained by the assembly of silica nanospheres of different sizes into a binary colloidal crystal. The colloidal crystal has a CrB-type structure and consists of alternate stacks of unary fcc and binary AlB2 -type structures along the b axis and has four types of interstitial mesopores. The BNMS can be deposited on a substrate by dip coating to form an oriented thin film in which the direction of the superstructure (b axis) is perpendicular to the substrate.
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http://dx.doi.org/10.1002/anie.201605027DOI Listing
August 2016

Efficacy and Safety of Weekly Paclitaxel Therapy for Advanced Gastric Cancer Patients with Disseminated Intravascular Coagulation.

J Gastrointest Cancer 2015 Dec;46(4):438-41

Osaki Citizen Hospital, 3-8-8 Furukawa-honami, Osaki, Miyagi, 989-6183, Japan.

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http://dx.doi.org/10.1007/s12029-015-9744-xDOI Listing
December 2015

Dual stimuli-sensitive dendrimers: Photothermogenic gold nanoparticle-loaded thermo-responsive elastin-mimetic dendrimers.

Colloids Surf B Biointerfaces 2015 Aug 14;132:155-60. Epub 2015 May 14.

Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan. Electronic address:

Dendrimers are synthetic macromolecules with unique structures that can work as nanoplatforms for both photothermogenic gold nanoparticles (AuNPs) and thermosensitive elastin-like peptides (ELPs) with valine-proline-glycine-valine-glycine (VPGVG) repeats. In this study, photothermogenic AuNPs were loaded into thermo-responsive elastin-mimetic dendrimers (dendrimers conjugating ELPs at their periphery) to produce dual stimuli-sensitive nanoparticles. Polyamidoamine G4 dendrimers were modified with acetylated VPGVG and (VPGVG)2, and the resulting materials were named ELP1-den and ELP2-den, respectively. The AuNPs were prepared by the reduction of Au ions using a dendrimer-nanotemplated method. The AuNP-loaded elastin-mimetic dendrimers exhibited photothermal properties. ELP1-den and ELP2-den showed similar temperature-dependent changes in their conformations. Phase transitions were observed at around 55°C and 35°C for the AuNP-loaded ELP1-den and AuNP-loaded ELP2-den, respectively, but not for the corresponding PEGylated dendrimer. In contrast to the AuNP-loaded PEGylated dendrimer, AuNP-loaded ELP2-den readily associated with cells and induced efficient photocytotoxicity at 37°C. The cell association and the photocytotoxicity properties of AuNP-loaded ELP2-den could be controlled by temperature. These results therefore suggest that dual stimuli-sensitive dendrimer nanoparticles of this type could be used for photothermal therapy.
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http://dx.doi.org/10.1016/j.colsurfb.2015.05.012DOI Listing
August 2015

[Chemotherapy-induced alopecia].

Nihon Rinsho 2015 Feb;73 Suppl 2:458-63

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February 2015

Electrochemical synthesis of mesoporous gold films toward mesospace-stimulated optical properties.

Nat Commun 2015 Mar 23;6:6608. Epub 2015 Mar 23.

1] World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan [2] Department of Nanoscience and Nanoengineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.

Mesoporous gold (Au) films with tunable pores are expected to provide fascinating optical properties stimulated by the mesospaces, but they have not been realized yet because of the difficulty of controlling the Au crystal growth. Here, we report a reliable soft-templating method to fabricate mesoporous Au films using stable micelles of diblock copolymers, with electrochemical deposition advantageous for precise control of Au crystal growth. Strong field enhancement takes place around the center of the uniform mesopores as well as on the walls between the pores, leading to the enhanced light scattering as well as surface-enhanced Raman scattering (SERS), which is understandable, for example, from Babinet principles applied for the reverse system of nanoparticle ensembles.
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http://dx.doi.org/10.1038/ncomms7608DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4382992PMC
March 2015

Room-temperature pressure-induced nanostructural CuInTe(2) thermoelectric material with low thermal conductivity.

Inorg Chem 2014 Jul 10;53(13):6844-9. Epub 2014 Jun 10.

Nanoscience and Nanotechnology Research Center, Research Organization for the 21st Century, Osaka Prefecture University , Gakuencho 1-2, Sakai 599-8570, Japan.

A room-temperature high-pressure synthesis method is proposed as an alternative way to induce nanoscale structural disorder in the bulk thermoelectric CuInTe2 matrix. This disorder stems from the coexistence of distinct domains with different degrees and geometries of disorder at Cu/In cation sites. The lattice thermal conductivity of high-pressure-treated CuInTe2 is substantially less than that of hot-pressed CuInTe2. The Debye-Callaway model reveals that the reduced lattice thermal conductivity is mainly attributed to disorder at the Cu/In cation sites and stacking faults, which were probably created during formation of the high-pressure-treated phases. This study demonstrates that room-temperature high-pressure synthesis can produce a radical change in the crystal structure and physical properties of conventional thermoelectric materials.
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http://dx.doi.org/10.1021/ic500688dDOI Listing
July 2014

Molecularly designed nanoparticles by dispersion of self-assembled organosiloxane-based mesophases.

Angew Chem Int Ed Engl 2014 Aug 6;53(35):9173-7. Epub 2014 Jun 6.

Department of Applied Chemistry, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan).

The design of siloxane-based nanoparticles is important for many applications. Here we show a novel approach to form core-shell silica nanoparticles of a few nanometers in size through the principle of "dispersion of ordered mesostructures into single nanocomponents". Self-assembled siloxane-organic hybrids derived from amphiphilic alkyl-oligosiloxanes were postsynthetically dispersed in organic solvent to yield uniform nanoparticles consisting of dense lipophilic shells and hydrophilic siloxane cores. In situ encapsulation of fluorescent dyes into the nanoparticles demonstrated their ability to function as nanocarriers.
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http://dx.doi.org/10.1002/anie.201404515DOI Listing
August 2014

Sample cleanup using solid-phase dispersive extraction for determination of vancomycin in serum.

Anal Sci 2014 ;30(2):271-5

Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Hoshi University.

A cleanup method employing quick and simple solid-phase dispersive extraction (SPDE) was investigated for its potential use in the determination of vancomycin (VCM) in serum by liquid chromatography/mass-spectrometry (LC/MS). SPDE was observed to be more rapid than conventional cartridge-type solid-phase extraction (SPE). In addition, in the analysis of viscous samples such as serum containing many proteins, SPDE could satisfactorily remove proteins even if deproteinization was not performed beforehand. The limit of detection (S/N = 3) and the limit of quantification (S/N > 10) of VCM by LC/MS were 0.05 and 0.2 ng/mL, respectively. The average recoveries of VCM from pooled serum spiked at 2, 10, and 100 ng/mL were 90.0, 90.8, and 98.6%, respectively. The repeatabilities were 7.5, 6.8, and 2.8%, and the intermediate precision values were 8.5, 6.8, and 7.0%, respectively. This suggests that the developed analytical method combing SPDE is useful for the determination of VCM in serum.
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http://dx.doi.org/10.2116/analsci.30.271DOI Listing
October 2014

High throughput RNAi screening identifies ID1 as a synthetic sick/lethal gene interacting with the common TP53 mutation R175H.

Oncol Rep 2014 Mar 30;31(3):1043-50. Epub 2013 Dec 30.

Department of Clinical Oncology, IDAC, Tohoku University, Sendai, Miyagi 980-8575, Japan.

The TP53 mutation (R175H) is one of the most common mutations in human cancer. It is a highly attractive strategy for cancer therapy to find the genes that lead the R175H-expressing cancer cells. The aim of this study was to identify the synthetic sick/lethal gene interacting with R175H. Using lentiviral bar-coded comprehensive shRNA library and a tetracycline-inducible R175H expressed in the SF126 human glioblastoma cell line (SF126-tet-R175H), we conducted high-throughput screening to identify the candidate genes that induce synthetic sickness/lethality in R175H-expressing cells. We identified 906 candidate gene suppressions that may lead to accelerated cell growth inhibition in the presence of R175H. Inhibitor of differentiation 1 (ID1) was one of the candidate genes, and its suppression by siRNA resulted in the acceleration of growth inhibition in cell lines both transiently and endogenously expressing R175H but not in TP53-null cell lines or other common p53 mutants (such as R273H). Flow cytometry analysis showed that ID1 suppression resulted in G1 arrest, and the arrest was accelerated by the expression of R175H. ID1 is a synthetic sick/lethal gene that interacts with R175H and is considered to be a novel molecular target for cancer therapy in R175H-expressing cells.
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http://dx.doi.org/10.3892/or.2013.2953DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3926671PMC
March 2014

Overexpression of DRAM enhances p53-dependent apoptosis.

Cancer Med 2013 Feb 3;2(1):1-10. Epub 2013 Feb 3.

Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University , 4-1 Seiryo-machi, Aoba-ku, Sendai, Japan.

Tumor suppressor p53-dependent apoptosis is thought to be one of the most important tumor-suppressive mechanisms in human tumorigenesis. Till date, "super p53" mutants exhibiting more potent ability to induce apoptosis than wild-type p53 have been reported. These super p53s may provide a clue for development of novel therapeutic targets. However, the major mechanism underlying the super p53-dependent apoptosis remains unclear. To identify critical gene(s) in this mechanism, we performed a comprehensive and comparative expression analysis in p53-null Saos-2 cells with conditional expression of wild-type p53 and S121F, which was previously reported as a super p53 mutant. We identified damage-regulated autophagy modulator (DRAM) as one of the genes that were more upregulated by S121F than wild-type p53. Although knockdown of DRAM was not sufficient for reducing the ability of S121F to induce apoptosis, DRAM overexpression enhanced the ability in a wild-type p53-dependent manner. Here, we show that DRAM is an important gene for the enhancement of p53-dependent apoptosis. Additional analysis of the mechanism of super p53-dependent apoptosis may lead to the identification of novel drug targets for cancer therapy.
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http://dx.doi.org/10.1002/cam4.39DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3797565PMC
February 2013

The role of curvature in silica mesoporous crystals.

Interface Focus 2012 Oct 8;2(5):634-44. Epub 2012 Feb 8.

Graduate School of EEWS (WCU) , Korea Advanced Institute of Science and Technology (KAIST) , Yuseong-gu, Daejeon 305-701 , Republic of Korea.

Silica mesoporous crystals (SMCs) offer a unique opportunity to study micellar mesophases. Replication of non-equilibrium mesophases into porous silica structures allows the characterization of surfactant phases under a variety of chemical and physical perturbations, through methods not typically accessible to liquid crystal chemists. A poignant example is the use of electron microscopy and crystallography, as discussed herein, for the purpose of determining the fundamental role of amphiphile curvature, namely mean curvature and Gaussian curvature, which have been extensively studied in various fields such as polymer, liquid crystal, biological membrane, etc. The present work aims to highlight some current studies devoted to the interface curvature on SMCs, in which electron microscopy and electron crystallography (EC) are used to understand the geometry of silica wall surface in bicontinuous and cage-type mesostructures through the investigation of electrostatic potential maps. Additionally, we show that by altering the synthesis conditions during the preparation of SMCs, it is possible to isolate particles during micellar mesophase transformations in the cubic bicontinuous system, allowing us to view and study epitaxial relations under the specific synthesis conditions. By studying the relationship between mesoporous structure, interface curvature and micellar mesophases using electron microscopy and EC, we hope to bring new insights into the formation mechanism of these unique materials but also contribute a new way of understanding periodic liquid crystal systems.
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http://dx.doi.org/10.1098/rsfs.2011.0098DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3438573PMC
October 2012

Platinum nanopeapods: spatial control of mesopore arrangements by utilizing a physically confined space.

Chemistry 2013 Aug 19;19(35):11564-7. Epub 2013 Jul 19.

Department of Applied Chemistry, Faculty of Science & Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555, Japan.

Spherical mesopores: Mesoporous Pt rods containing cage-type mesopores were prepared with porous anodic alumina membranes (PAAMs). It is noteworthy that spherical mesopores are aligned in the rods due to physical confinement by the PAAM channels. Both the mesopore alignment and the morphological control are realized simultaneously, which could be important for bottom-up approaches to nanometals with desirable structural features (see figure).
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http://dx.doi.org/10.1002/chem.201300449DOI Listing
August 2013

A review of fine structures of nanoporous materials as evidenced by microscopic methods.

Microscopy (Oxf) 2013 Feb 24;62(1):109-46. Epub 2013 Jan 24.

National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.

This paper reviews diverse capabilities offered by modern electron microscopy techniques in studying fine structures of nanoporous crystals such as zeolites, silica mesoporous crystals, metal organic frameworks and yolk-shell materials. For the case of silica mesoporous crystals, new approaches that have been developed recently to determine the three-dimensionally periodic average structure, e.g., through self-consistent analysis of electron microscope images or through consideration of accidental extinctions, are presented. Various structural deviations in nanoporous materials from their average structures including intergrowth, surface termination, incommensurate modulation, quasicrystal and defects are demonstrated. Ibidem observations of the scanning electron microscope and atomic force microscope give information about the zeolite-crystal-growth mechanism, and an energy for unstitching a building-unit from a crystal surface is directly observed by an anatomic force microscope. It is argued how these observations lead to a deeper understanding of the materials.
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http://dx.doi.org/10.1093/jmicro/dfs098DOI Listing
February 2013

Dodecagonal tiling in mesoporous silica.

Nature 2012 Jul 18;487(7407):349-53. Epub 2012 Jul 18.

Department of Materials and Environmental Chemistry, Bezelii Center EXSELENT on Porous Materials, Stockholm University, S-10691 Stockholm, Sweden.

Recent advances in the fabrication of quasicrystals in soft matter systems have increased the length scales for quasicrystals into the mesoscale range (20 to 500 ångströms). Thus far, dendritic liquid crystals, ABC-star polymers, colloids and inorganic nanoparticles have been reported to yield quasicrystals. These quasicrystals offer larger length scales than intermetallic quasicrystals (a few ångströms), thus potentially leading to optical applications through the realization of a complete photonic bandgap induced via multiple scattering of light waves in virtually all directions. However, the materials remain far from structurally ideal, in contrast to their intermetallic counterparts, and fine control over the structure through a self-organization process has yet to be attained. Here we use the well-established self-assembly of surfactant micelles to produce a new class of mesoporous silicas, which exhibit 12-fold (dodecagonal) symmetry in both electron diffraction and morphology. Each particle reveals, in the 12-fold cross-section, an analogue of dodecagonal quasicrystals in the centre surrounded by 12 fans of crystalline domains in the peripheral part. The quasicrystallinity has been verified by selected-area electron diffraction and quantitative phason strain analyses on transmission electron microscope images obtained from the central region. We argue that the structure forms through a non-equilibrium growth process, wherein the competition between different micellar configurations has a central role in tuning the structure. A simple theoretical model successfully reproduces the observed features and thus establishes a link between the formation process and the resulting structure.
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http://dx.doi.org/10.1038/nature11230DOI Listing
July 2012

Induction of apoptosis by cytoplasmically localized wild-type p53 and the S121F mutant super p53.

Oncol Lett 2012 May 29;3(5):978-982. Epub 2012 Feb 29.

Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi 980-8575, Japan.

After DNA damage, p53 is accumulated in the nucleus and transactivates downstream genes and induces apoptosis. There are two pathways in p53-dependent apoptosis, the transactivation-dependent and -independent pathway. In this study, we constructed p53-inducible glioblastoma cell lines and analyzed them for the induction of apoptosis and transactivation of p53-downstream genes after the nuclear or cytoplasmic expression of p53. To sequester p53 in the cytoplasm, we used p53 mutant with arginine to glycine substitution at residue 306 (R306G). Wild-type p53 retained the ability to arrest the cell cycle, and a p53 mutant with serine to phenylalanine substitution at residue 121 (S121F), which has a strong ability to induce apoptosis, retained this ability even when both the wild-type and p53 and S121F mutant were exclusively sequestered from the nucleus into the cytoplasm. Notably, cytoplasmically sequestered wild-type p53 and S121F mutant transactivated the downstream genes with distinct expression profiles, and the strong apoptotic ability of S121F was not associated with its transactivation activity. These results underscore the existence of transactivation-independent apoptosis and cytoplasmic function of p53.
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http://dx.doi.org/10.3892/ol.2012.624DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3389701PMC
May 2012

Transient colloidal stability controls the particle formation of SBA-15.

Langmuir 2012 Aug 23;28(31):11567-74. Epub 2012 Jul 23.

Physical Chemistry, Lund University, Lund, Sweden.

A hypothesis about (transient) colloidal stability as a controlling mechanism for particle formation in SBA-15 is presented. The hypothesis is based on results from both in situ and ex situ investigations, including cryogenic transmission electron microscopy (cryo-TEM), UV-vis spectroscopy, and dynamic light scattering (DLS). Cryo-TEM images show that particles grow via the formation of silica-Pluronic-water "flocs", which coalesce in a seemingly arbitrary manner. Despite this, the final material consists of well-defined particles with a small size distribution. We argue that the interface between the flocs and surrounding media is covered by Pluronic molecules, which provide steric stabilization. As the flocs grow, the coverage of polymers at the interface is increased until a stable size is reached, and that regulates the particle size. By targeting the characteristics of the Pluronic molecules, during the on-going synthesis, the hypothesis is tested. The results are consistent with the concept of (transient) colloidal stability.
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http://dx.doi.org/10.1021/la3013969DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3836357PMC
August 2012

Selective cleavage of periodic mesoscale structures: two-dimensional replication of binary colloidal crystals into dimpled gold nanoplates.

J Am Chem Soc 2012 May 4;134(20):8684-92. Epub 2012 May 4.

Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Shinjuku-ku, Tokyo, Japan.

Specific crystallographic planes of binary colloidal crystals consisting of silica nanoparticles are two-dimensionally replicated on the surface of gold nanoplates. The selectivity of the surface patterns is explained by the geometrical characteristics of the binary colloidal crystals as templates. The binary colloidal crystals with the AlB(2)- and NaZn(13)-type structures are fabricated from aqueous dispersions of stoichiometrically mixed silica nanoparticles with different sizes. The stoichiometry is precisely controlled on the basis of a seed growth of silica nanoparticles. Dimpled gold nanoplates are formed by the two-dimensional growth of gold between partially cleaved surfaces of templates. The selectivity of the surface patterns is explained using the AlB(2)-type binary colloidal crystal as a template. The surface pattern is determined by the preferential cleavage of the plane with the lowest density of particle-particle connections. The tendency to form well-defined cleavage in binary colloidal crystals is crucial to formation of dimpled gold nanoplates, which is explained using the NaZn(13)-type binary colloidal crystal as a template. Its complex structure does not show well-defined cleavage, and only distorted nanoplates are obtained. Therefore, the mechanism of the two-dimensional replication of binary colloidal crystals is reasonably explained on the basis of their periodic mesoscale structures and crystal-like properties.
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http://dx.doi.org/10.1021/ja3026054DOI Listing
May 2012

A mesoporous γ-alumina film with vertical mesoporosity: the unusual conversion from a Im3m mesostructure to vertically oriented γ-alumina nanowires.

Angew Chem Int Ed Engl 2011 Aug 17;50(32):7410-3. Epub 2011 Jun 17.

Metallurgy and Materials Engineering Department, Tarbiat Moallem University of Sabzevar, Sabzevar, Iran.

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http://dx.doi.org/10.1002/anie.201008192DOI Listing
August 2011
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