Y. Sakurai

Japan Synchrotron Radiation Research Institute (JASRI), Tatsuno, Hyōgo, Japan

Are you Y. Sakurai?

Claim your profile

Publications (306)644.87 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of the present study was to evaluate the effect of bevacizumab on local tumor response and lung metastatic potential during boron neutron capture therapy (BNCT) and in particular, the response of intratumor quiescent (Q) cells. B16-BL6 melanoma tumor-bearing C57BL/6 mice were continuously administered bromodeoxyuridine (BrdU) to label all proliferating (P) tumor cells. The tumors were irradiated with thermal neutron beams following the administration of a (10)B-carrier [L-para-boronophenylalanine-(10)B (BPA) or sodium mercaptoundecahydrododecaborate-(10)B (BSH)], with or without the administration of bevacizumab. This was further combined with an acute hypoxia-releasing agent (nicotinamide) or mild temperature hyperthermia (MTH, 40°C for 60 min). Immediately following the irradiation, cells from certain tumors were isolated and incubated with a cytokinesis blocker. The responses of the Q cells and the total (P+Q) cell populations were assessed based on the frequency of micronuclei using immunofluorescence staining for BrdU. In other tumor-bearing mice, 17 days following irradiation, lung metastases were enumerated. Three days following bevacizumab administration, the sensitivity of the total tumor cell population following BPA-BNCT had increased more than that following BSH-BNCT. The combination with MTH, but not with nicotinamide, further enhanced total tumor cell population sensitivity. Regardless of the presence of a (10)B-carrier, MTH enhanced the sensitivity of the Q cell population. Regardless of irradiation, the administration of bevacizumab, as well as nicotinamide treatment, demonstrated certain potential in reducing the number of lung metastases especially in BPA-BNCT compared with BSH-BNCT. Thus, the current study revealed that BNCT combined with bevacizumab has the potential to sensitize total tumor cells and cause a reduction in the number of lung metastases to a similar level as nicotinamide.
    Experimental and therapeutic medicine 07/2014; 8(1):291-301. · 0.34 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present the spin momentum density of Ga doped CoFe2O4 at 100 K using magnetic Compton scattering. The measurement has been performed using circularly polarized synchrotron radiations of 182.65 keV at SPring8, Japan. The experimental profile is decomposed into its constituent profile to determine the spin moment at individual sites. Co atom has the maximum contribution (about 58%) in the total spin moment of the doped CoFe2O4.
    03/2014; 1591(1).
  • [Show abstract] [Hide abstract]
    ABSTRACT: New anti-cancer therapy with boron neutron capture therapy (BNCT) is based on the nuclear reaction of boron-10 with neutron irradiation. The median survival of BNCT patients with glioblastoma was almost twice as long as those receiving standard therapy in a Japanese BNCT clinical trial. In this clinical trial, two boron compounds, BPA (boronophenylalanine) and BSH (sodium borocaptate), were used for BNCT. BPA is taken up into cells through amino acid transporters that are expressed highly in almost all malignant cells, but BSH cannot pass through the cell membrane and remains outside the cell. We simulated the energy transfer against the nucleus at different locations of boron from outside the cell to the nuclear region with neutron irradiation and concluded that there was a marked difference between inside and outside the cell in boron localization. To overcome this disadvantage of BSH in BNCT, we used a cell-penetrating peptide system for transduction of BSH. CPP (cell-membrane penetrating peptide) is very common peptide domains that transduce many physiologically active substances into cells in vitro and in vivo. BSH-fused CPPs can penetrate the cell membrane and localize inside a cell. To increase the boron ratio in one BSH-peptide molecule, 8BSH fused to 11R with a dendritic lysine structure was synthesized and administrated to malignant glioma cells and a brain tumor mouse model. 8BSH-11R localized at the cell nucleus and showed a very high boron value in ICP results. With neutron irradiation, the 8BSH-11R administrated group showed a significant cancer killing effect compared to the 100 times higher concentration of BSH-administrated group. We concluded that BSH-fused CPPs were one of the most improved and potential boron compounds in the next-stage BNCT trial and 8BSH-11R may be applied in the clinical setting.
    Biomaterials 01/2014; · 8.31 Impact Factor
  • Kenichi Tanaka, Yoshinori Sakurai, Satoru Endo, Jun Takada
    [Show abstract] [Hide abstract]
    ABSTRACT: In order to measure the spatial distributions of neutrons and gamma rays separately using the imaging plate, the requirement for the converter to enhance specific component was investigated with the PHITS code. Consequently, enhancing fast neutrons using recoil protons from epoxy resin was not effective due to high sensitivity of the imaging plate to gamma rays. However, the converter of epoxy resin doped with 10B was found potential for thermal and epithermal neutrons, and graphite for gamma rays.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 01/2014; · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Temperature dependent spin momentum densities of NiFe2−xRExO4 (x=0, 0.05; RE=Dy, Gd) ferrites have been measured using a magnetic Compton spectrometer available at SPring-8, Japan. The experimental profiles of NiFe2O4 (NFO) with doping of Dy and Gd show almost similar spin moment as of undoped NFO. The contribution of different constituents in the formation of total spin moment is also deduced from the analysis of Compton line shape. It is seen that 5% doping of Dy3+ or Gd3+ ions at Fe3+ sites leads to a redistribution of spin moment at Fe3+ and RE3+ sites. The magnetic Compton data when compared with the magnetization data (using a vibrating sample magnetometer) show almost a constant orbital moment (0.21±0.03 µB/f.u.) in the doped and undoped NFO.
    Journal of Magnetism and Magnetic Materials 01/2014; 360:113–117. · 2.00 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: It is important to measure the microdistribution of 10B in a cell to predict the cell-killing effect of new boron compounds in the field of boron neutron capture therapy. Alpha autoradiography has generally been used to detect the microdistribution of 10B in a cell. Although it has been performed using a reactor-based neutron source, the realization of an accelerator-based thermal neutron irradiation field is anticipated because of its easy installation at any location and stable operation. Therefore, we propose a method using a cyclotron-based epithermal neutron source in combination with a water phantom to produce a thermal neutron irradiation field for alpha autoradiography. This system can supply a uniform thermal neutron field with an intensity of 1.7×109 (cm−2 s−1) and an area of 40 mm in diameter. In this presentation, we give an overview of our proposed system and describe a demonstration test using a mouse liver sample injected with 500 mg/kg of boronophenyl-alanine.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 01/2014; · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 63-year-old man with multiple HCC in his left liver lobe was enrolled as the first patient in a pilot study of boron neutron capture therapy (BNCT) involving the selective intra-arterial infusion of a 10BSH-containing water-in-oil-in-water emulsion (10BSH-WOW). The size of the tumorous region remained stable during the 3 months after the BNCT. No adverse effects of the BNCT were observed. The present results show that 10BSH-WOW can be used as novel intra-arterial boron carriers during BNCT for HCC.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 01/2014; · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Radiation doses during boron neutron capture therapy for body-trunk tumors were estimated for various internal organs, using data from patients treated at Kyoto University Research Reactor Institute. Dose-volume histograms were constructed for tissues of the lung, liver, kidney, pancreas, and bowel. For pleural mesothelioma, the target total dose to the normal lung tissues on the diseased side is 5 Gy-Eq in average for the whole lung. It was confirmed that the dose to the liver should be carefully considered in cases of right lung disease.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 01/2014; · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: As a nanoparticulate device for controlled delivery of Gd in NCT, the authors have developed gadolinium-loaded chitosan nanoparticles (Gd-nanoCPs). In the present study, influence of micrometric properties such as particle size, particle-surface charge and Gd content of Gd-nanoCPs on tumor-killing effect by Gd-NCT was investigated with Gd-nanoCPs. Two types of Gd-nanoCPs with different mean particle size, zeta potential and Gd-content (Gd-nanoCP-400; 391nm, 28mV, 9wt% and Gd-nanoCP-200; 214nm, 19mV, 24wt%) could be prepared by using chitosans with different molecular weights. Gd-nanoCPs incorporating 1.2mg of natural Gd were injected intratumorally once or twice to mice subcutaneously-bearing B16F10 melanoma. Eight hours after the last administration, thermal neutron was irradiated to tumor region of the mice. Remarkable tumor-growth was observed in both hot and cold control groups. In contrast, Gd-NCT groups showed significant tumor-growth suppression effect, though their efficacy was found to depend on the micrometric properties of Gd-nanoCPs. In particular, the Gd-nanoCP-200 exhibited stronger tumor-killing effect than the Gd-nanoCP-400 at the same Gd dose and it was still similar to Gd-nanoCP-400 in tumor-growth suppressing effect even at the half of Gd dose of Gd-nanoCP-400. This significance in tumor-killing effect would be ascribed from a higher Gd retention in the tumor tissue and an improved distribution of Gd with intratumorally administered Gd-nanoCP-200. Indeed, the Gd concentration in tumor tissue at the time corresponding to the onset of thermal neutron irradiation was determined to be significantly higher in Gd-nanoCP-200, compared with Gd-nanoCP-400. These results demonstrated that appropriate modification of Gd-nanoCPs in micrometric properties would be an effective way to improve the retention of Gd in the tumor tissue after intratumoral injection, leading to the enhanced tumor-killing effect in Gd-NCT.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 12/2013; · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Clear cell sarcoma (CCS) is a rare malignant tumor with a poor prognosis. In our previous study, the tumor disappeared under boron neutron capture therapy (BNCT) on subcutaneously-transplanted CCS-bearing animals. In the present study, the tumor disappeared under this therapy on model mice intramuscularly implanted with three different human CCS cells. BNCT led to the suppression of tumor-growth in each of the different model mice, suggesting its potentiality as an alternative to, or integrative option for, the treatment of CCS.
    Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine 12/2013; · 1.09 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Boron neutron capture therapy (BNCT) is a selective radiotherapy that is dependent on the accumulation of 10B compound in tumors. Low-intensity ultrasound produces a transient pore on cell membranes, sonoporation, which enables extracellular materials to enter cells. The effect of sonoporation on BNCT was examined in oral squamous cell carcinoma (SCC) xenografts in nude mice.Materials and methods: Tumor-bearing mice were administrated boronophenylalanine (BPA) or boronocaptate sodium (BSH) intraperitoneally. Two hours later, tumors were subjected to sonoporation using microbubbles followed by neutron irradiation. The 10B concentration was higher in tumors treated with sonoporation than in untreated tumors, although the difference was not significant in BPA. When tumors in mice that received BPA intraperitoneally were treated with sonoporation followed by exposure to thermal neutrons, tumor volume was markedly reduced and the survival rate was prolonged. Such enhancements by sonoporation were not observed in mice treated with BSH-mediated BNCT. These results indicate that sonoporation enhances the efficiency of BPA-mediated BNCT for oral SCC. Sonoporation may modulate the microlocalization of BPA and BSH in tumors and increase their intracellular levels.
    Radiation Oncology 12/2013; 8(1):280. · 2.11 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Boron neutron capture therapy (BNCT) can be utilized to selectively kill cancer cells using a boron compound that accumulates only in cancer cells and not in normal cells. Tumor-bearing animals treated by BNCT are routinely used to evaluate long-term antitumor effects of new boron compounds. Alpha-autoradiography is one of the methods employed in the evaluation of antitumor effects. However, a standard alpha-autoradiography cannot detect the microdistribution of (10)B because of the difficulty associated with the superposition of a tissue sample image and etched pits on a track detector with the etching process. In order to observe the microdistribution of (10)B, some special methods of alpha-autoradiography have been developed that make use of a special track detector, or the atomic force microscope combined with X-ray and UV light irradiation. In contrast, we propose, herein, a simple and rapid method of precisely identifying the position of (10)B using the imaging process and the shape of etched pits, such as their circularity, without the need to use special track detectors or a microscope. A brief description of this method and its verification test are presented in this article. We have established a method of detecting the microdistribution of (10)B with submicron deviation between the position of etched pits and the position of reaction in a tissue sample, for a given circularity of etched pits.
    Journal of Radiation Research 10/2013; · 1.45 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The electron momentum density (EMD) in liquid silicon (Si) has been measured by synchrotron-based Compton scattering. The observed variation in the valence EMD upon melting, reflecting a semiconductor-metal transition of Si, is well explained by the collapse of the Jones zone of crystalline Si. However, the shape of the EMD of liquid Si is considerably broad and retains fairly solid (α-Si)-like characteristics. The analysis of the Fourier-transformed Compton profiles reveals that the valence electronic state in liquid Si exhibits a marked deviation from the free-electron gas features.
    Physical Review B 09/2013; 88(11). · 3.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We retrospectively review outcomes of applying boron neutron capture therapy (BNCT) to unresectable advanced or recurrent head and neck cancers. Patients who were treated with BNCT for either local recurrent or newly diagnosed unresectable head or neck cancers between December 2001 and September 2007 were included. Clinicopathological characteristics and clinical outcomes were retrieved from hospital records. Either a combination of borocaptate sodium and boronophenylalanine (BPA) or BPA alone were used as boron compounds. In all the treatment cases, the dose constraint was set to deliver a dose <10-12 Gy-eq to the skin or oral mucosa. There was a patient cohort of 62, with a median follow-up of 18.7 months (range, 0.7-40.8). A total of 87 BNCT procedures were performed. The overall response rate was 58% within 6 months after BNCT. The median survival time was 10.1 months from the time of BNCT. The 1- and 2-year overall survival (OS) rates were 43.1% and 24.2%, respectively. The major acute Grade 3 or 4 toxicities were hyperamylasemia (38.6%), fatigue (6.5%), mucositis/stomatitis (9.7%) and pain (9.7%), all of which were manageable. Three patients died of treatment-related toxicity. Three patients experienced carotid artery hemorrhage, two of whom had coexistent infection of the carotid artery. This study confirmed the feasibility of our dose-estimation method and that controlled trials are warranted.
    Journal of Radiation Research 08/2013; · 1.45 Impact Factor
  • Source
    Dataset: nano-prl
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Temperature dependent experimental magnetic Compton profiles (MCPs) of inverse spinel CoFe2�-xRExO4 (x=0.05; RE=Dy, Gd) have been decomposed into constituent profiles to determine site-specific spin moments. A comparison of MCPs of doped and undoped CoFe2O4 shows a decrease in spin moment on 5% doping of Dy and Gd. Reduction in spin moment is explained on the basis of migration of Co2+ ions from octahedral to tetrahedral sites, which is also supported by photoelectron spectroscopy measurements. The orbital moments deduced from combination of spin momentum density and magnetization data are found to be almost similar in doped ferrites.
    Applied Physics Letters 06/2013; 102:232403. · 3.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The crystallographic, magnetic and transport properties of Sr1−x Cax Ru0.5Mn0.5O3 were studied to reveal the effects of crystal symmetry on the magnetism and the transport properties of antiferromagnetic SrRu1−y Mny O3 (y > 0.2). The Ca-content dependences of the lattice constants and volume suggest that the mixed valence state of Mn3+, Mn4+, Ru4+, and Ru5+ ions in SrRu0.5Mn0.5O3 is held for Ca substitution. However, a structural transformation from tetragonal to orthorhombic symmetry occurs at a Ca content of x ∼ 0.2, and a ferromagnetic state appears simultaneously. The Weiss temperature of all samples has a positive value regardless of the magnetic state. The resistivity decreases as the Ca content increases, and the high temperature part of the resistivity could be fitted by using the variable range hopping (VRH) model. The localization length increases as soon as ferromagnetism appears. The Curie temperature seems to depend on the distance between transition metal ions. The antiferromagnetic state was explained by using the competition between a ferromagnetic interaction along the c-axis and an antiferromagnetic interaction in the ab-plane, and the orthorhombic ferromagnetic state was explained by using a three-dimensional ferromagnetic interaction between Mn ions.
    Journal- Korean Physical Society 06/2013; 62(12). · 0.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: We revealed that the Ba(Co0.85Mn0.15)O3-δ ceramic samples exhibited ferromagnetic-dielectric behavior below the magnetic transition temperature of about 35 K. The origin of their magnetic ordering was expected to super-exchange coupling of Co(4+)(d (5))-O(2-)-Mn(4+)(d (3)) with bonding angle of 180° and/or Mn(4+)(d (3))-O(2-)-Mn(4+)(d (3)) with bonding angle of 90°. The magnetic spin momentum estimated by the magnetic Compton profiles (MCP) of the samples had similar temperature dependence as that determined by the temperature dependence of magnetic moment by superconducting quantum interference device, which meant that the observed magnetic moments could be ascribed to the spin moment. The shapes of the MCPs of the samples were completely same regardless of the temperature measured. This result indicates that there are no changes of the momentum space distribution of spin density between ferromagnetic and paramagnetic states. So, this magnetic transition is simply caused by a thermal fluctuation of the spin.
    Journal of Applied Physics 05/2013; 113(17):17E307. · 2.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Remarkable applicability of magnetic Compton scattering (MCS) in deducing site specific small spin moments like those in LaFe1−xNixO3 (x = 0.4 and 0.5) is established. The MCS measurements revealed that Fe site gives a dominant contribution (although small) to total magnetic moment, while the contribution of Ni spin moment is found to be antiparallel to that of Fe moment. Present work, which instigates insignificant role of orbital moment and diffused components in the formation of total magnetic moment, triggers era of applications of MCS in ferrimagnetic compounds with small magnetic moments.
    Applied Physics Letters 04/2013; 102(14). · 3.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Remarkable applicability of magnetic Compton scattering (MCS) in deducing site specific small spin moments like those in LaFe1�xNixO3 (x¼0.4 and 0.5) is established. The MCS measurements revealed that Fe site gives a dominant contribution (although small) to total magnetic moment, while the contribution of Ni spin moment is found to be antiparallel to that of Fe moment. Present work, which instigates insignificant role of orbital moment and diffused components in the formation of total magnetic moment, triggers era of applications of MCS in ferrimagnetic compounds with small magnetic moments.
    Applied Physics Letters 04/2013; 102:142403-1 to 4. · 3.79 Impact Factor

Publication Stats

1k Citations
644.87 Total Impact Points

Institutions

  • 2000–2014
    • Japan Synchrotron Radiation Research Institute (JASRI)
      Tatsuno, Hyōgo, Japan
  • 1994–2014
    • Kyoto University
      • • Research Reactor Institute
      • • Department of Nuclear Engineering
      • • Graduate School of Medicine / Faculty of Medicine
      Kioto, Kyōto, Japan
  • 2012
    • Fudan University
      • Department of Oncology
      Shanghai, Shanghai Shi, China
    • Japan Aerospace Exploration Agency
      • Institute of Space and Astronautical Science (ISAS)
      Chōfu, Tokyo-to, Japan
  • 2006–2012
    • Aoyama Gakuin University
      • • Department of Electrical Engineering and Electronics
      • • College of Science and Engineering
      Tokyo, Tokyo-to, Japan
  • 2011
    • University of Hyogo
      • Graduate School of Material Science
      Akō, Hyogo-ken, Japan
    • Osaka Prefecture University
      Sakai, Ōsaka, Japan
    • The University of Tokushima
      • Department of Life Systems
      Tokushima-shi, Tokushima-ken, Japan
  • 2010–2011
    • Mohan Lal Sukhadia University
      • Department of Physics
      Udaipur, Rajasthan, India
    • University of Michigan
      • Department of Chemistry
      Ann Arbor, MI, United States
  • 2003–2011
    • Osaka Medical College
      • Department of Neurosurgery
      Takatuki, Ōsaka, Japan
  • 2006–2010
    • Osaka City University
      Ōsaka, Ōsaka, Japan
  • 2009
    • University of Bristol
      Bristol, England, United Kingdom
    • Northeastern University
      • Department of Physics
      Boston, MA, United States
  • 2006–2009
    • University of Helsinki
      • Department of Physical Sciences
      Helsinki, Province of Southern Finland, Finland
  • 2008
    • Aichi Cancer Center
      Ōsaka, Ōsaka, Japan
  • 2007–2008
    • Sapporo Medical University
      Sapporo, Hokkaidō, Japan
  • 2004
    • Osaka University
      • Department of Oral and Maxillofacial Surgery 2
      Ibaraki, Osaka-fu, Japan
  • 2001–2003
    • Himeji Institute of Technology
      Himezi, Hyōgo, Japan
    • Tokyo University of Science
      • Department of Pure and Applied Chemistry
      Tokyo, Tokyo-to, Japan
  • 2002
    • Hiroshima University
      • Research Institute for Radiation Biology and Medicine (RIRBM)
      Hiroshima-shi, Hiroshima-ken, Japan
  • 1983–2000
    • Tokyo Gakugei University
      • Department of Natural and Environmental Science
      Koganei, Tōkyō, Japan
  • 1995
    • RIKEN
      Вако, Saitama, Japan
  • 1987–1990
    • The University of Tokyo
      • Institute of Industrial Science
      Tokyo, Tokyo-to, Japan
  • 1989
    • Tohoku University
      • Institute for Materials Research
      Sendai-shi, Miyagi-ken, Japan