Takeru Ohkubo

In-air micro-particle induced X-ray emission analysis of asbestos and metals in lung tissue.

Inhalation of asbestos increases the risk of lung cancer and pulmonary fibrosis. It is difficult to directly assess the distribution and content of inhaled particles in lung tissue sections. The purpose of this study is to employ an in-air micro particle induced X-ray emission (in-air micro-PIXE) system for assessment of the spatial distribution and content of asbestos and other metals in lung tissue. A proton ion-microbeam from this system was applied to irradiate lung tissue of patients with or without asbestosis, tumor tissue from both groups, and asbestos fibers (in vitro). The content of each element composing asbestos and those of other metals were calculated and their distribution was assessed from the characteristic X-ray pattern for each element obtained after irradiation. This in-air micro-PIXE system could identify the location of asbestos bodies composed of Si, Mg, and Fe in lung tissue sections. Macrophage and lymphocytes accumulated in that area. This new system also revealed deposits of titanium, nickel, and cobalt in the lung tissues, in addition to asbestos bodies. The Si and Fe content were higher in lungs with asbestosis than in lungs without asbestosis or in tumor tissue. Analysis of asbestos fibers composed of chrysotile, crocidolite, and amosite showed that the ratios of Si, Fe, and Mg corresponded with those for the chemical structures. In-air micro-PIXE analysis is useful for assessing the distribution and quantities of asbestos bodies and also other metals in lung tissue comparing to immune-related cell localizations, and is also useful for analysis of standard asbestos fibers.

Elemental analysis of lung tissue particles and intracellular iron content of alveolar macrophages in pulmonary alveolar proteinosis

BackgroundPulmonary alveolar proteinosis (PAP) is a rare disease occurred by idiopathic (autoimmune) or secondary to particle inhalation. The in-air microparticle induced X-ray emission (in-air micro-PIXE) system performs elemental analysis of materials by irradiation with a proton microbeam, and allows visualization of the spatial distribution and quantitation of various elements with very low background noise. The aim of this study was to assess the secondary PAP due to inhalation of harmful particles by employing in-air micro-PIXE analysis for particles and intracellular iron in parafin-embedded lung tissue specimens obtained from a PAP patient comparing with normal lung tissue from a non-PAP patient. The iron inside alveolar macrophages was stained with Berlin blue, and its distribution was compared with that on micro-PIXE images.ResultsThe elements composing particles and their locations in the PAP specimens could be identified by in-air micro-PIXE analysis, with magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), scandium (Sc), potassium (K), calcium (Ca), titanium (Ti), chromium (Cr), copper (Cu), manganase (Mn), iron (Fe), and zinc (Zn) being detected. Si was the major component of the particles. Serial sections stained by Berlin blue revealed accumulation of sideromacrophages that had phagocytosed the particles. The intracellular iron content of alveolar macrophage from the surfactant-rich area in PAP was higher than normal lung tissue in control lung by both in-air micro-PIXE analysis and Berlin blue staining.ConclusionThe present study demonstrated the efficacy of in-air micro-PIXE for analyzing the distribution and composition of lung particles. The intracellular iron content of single cells was determined by simultaneous two-dimensional and elemental analysis of paraffin-embedded lung tissue sections. The results suggest that secondary PAP is associated with exposure to inhaled particles and accumulation of iron in alveolar macrophages.

Analysis on the Co-Localization of Asbestos Bodies and Fas or CD163 Expression in Asbestos Lung Tissue by in-Air Micro-Pixe

To prevent and control diseases caused by exposure to various agents, it is necessary to determine the harmful level for intervention and to establish a method for measuring that level. In-air microparticle-induced X-ray emission (in-air micro-PIXE) analysis is based on irradiation of specimens with a proton ion microbeam, and has been modified for biological application. Two-dimensional analysis and quantitative analysis using the system confirmed that asbestos induced apoptosis by upregulating Fas expression and also revealed the accumulation of CD163-expressing macrophages in the lungs of patients with asbestosis. By quantitative comparison of the area of Fas or CD163 expression and the Fas- or CD163-negative area in asbestos lung tissue, the harmful levels which caused the expression of Fas or CD163 could be estimated on Silica, Ferrous iron, and Magnesium (the components of asbestos) deposition. These results indicate that the system could be useful for investigating the pathogenesis of inhaled particle-induced immune reactions and for determining harmful levels of exogenous agents.

Co-localization of iron binding on silica with p62/sequestosome1 (SQSTM1) in lung granulomas of mice with acute silicosis.

The cellular mechanisms involved in the development of silicosis have not been fully elucidated. This study aimed to examine influence of silica-induced lung injury on autophagy. Suspensions of crystalline silica particles were administered transnasally to C57BL/6j mice. Immunohistochemical examination for Fas and p62 protein expression was performed using lung tissue specimens. Two-dimensional and quantitative analysis of silica deposits in the lungs were performed in situ using lung tissue sections by an in-air microparticle induced X-ray emission (in-air micro-PIXE) analysis system, which was based on irrradiation of specimens with a proton ion microbeam. Quantitative analysis showed a significant increase of iron levels on silica particles (assessed as the ratio of Fe relative to Si) on day 56 compared with day 7 (p<0.05). Fas and p62 were expressed by histiocytes in granulomas on day 7, and the expressions persisted for day 56. Fas- and p62-expressing histiocytes were co-localized in granulomas with silica particles that showed an increase of iron levels on silica particles in mouse lungs. Iron complexed with silica induces apoptosis, and may lead to dysregulations of autophagy in histiocytes of granulomas, and these mechanisms may contribute to granuloma development and progression in silicosis.

Development of micromachining technology in ion microbeam system at TIARA, JAEA

An ion-beam-lithography technique has been progressed in the microbeam systems at Japan Atomic Energy Agency (JAEA) Takasaki. In order to obtain a high-precision measure for microbeam size estimation with a high precision, we applied this technique combined with the electroplating process to make a Ni relief pattern as a resolution standard used in secondary electron imaging. As a result, the smallest beam size could be recorded. The scattering of ions in the materials influenced the spatial resolution and this is also discussed.

Demonstration of Thermo-Optic Switch Consisting of Mach-Zehnder Polymer Waveguide Drawn Using Focused Proton Beam

We demonstrated a PMMA-based thermo-optic switch consisting of a Mach-Zehnder (MZ) type waveguide drawn by proton beam writing (PBW) and working at λ = 1.55 μm. The MZ waveguide was drawn by symmetrically coupling two Y junctions with a core width of 8 μm and a branching angle of 2°. A Ti thin-film heater and Al electrodes were formed on the surface of the MZ waveguide using conventional photolithography and wet-etching processes. An ON/OFF ratio of 9.0 dB and a switching power of 43.9 mW were obtained from the sample. The switching power is lower than for conventional commercial silica-based switches.

Fabrication of Mach-Zehnder Polymer Waveguides by a Direct-Drawing Technique Using a Focused Proton Beam

Proton beam writing (PBW) has recently attracted much attention as a next-generation microfabrication technology. This is a direct-drawing technique and does not need any masks to transfer micropatterns to sample surfaces. In our previous work, we demonstrated the first single-mode straight-line and Y-junction PMMA-based waveguides fabricated using PBW and working at λ = 1.55 μm. In this work, we fabricated the first PMMA-based Mach-Zehnder waveguides for the wavelength utilizing PBW in order to construct thermo-optic switches.

Fabrication of polymer optical waveguides for the 1.5-μm band using focused proton beam

Proton beam writing (PBW) has attracted much attention recently as a next-generation micro-fabrication technology. It is a direct-drawing technique and does not need any masks to transfer micro-patterns to sample surfaces. In addition, the refractive index of a poly (methyl methacrylate) (PMMA) can be increased by proton-beam irradiation. In this study, we fabricated the first 1.5-μm-band single-mode, straight-line waveguides and Y-junction waveguides consisting of PMMA layers using the PBW technique.

In-air microparticle induced X-ray emission analysis of particles in interstitial pneumonia lung tissue obtained by transbronchial biopsy

Interstitial pneumonia develops in association with inhaled particles. In-air microparticle induced X-ray emission (in-air micro) analysis was previously employed to assess the spatial distribution and content of particles in surgical lung biopsy specimens. The aim of this study was to assess the efficacy of in-air micro-analysis for transbronchial lung biopsy specimens in patients with or without occupational exposure. The elements composing lung particles and their locations could be identified by in-air micro-analysis. Silicon was the major component of particles. Quantitative analysis revealed that the elements composing lung particles varied between patients. In a patient with suspected nickel exposure, aluminium, vanadium, and calcium were detected, but was not detected. In a patient without a work history (housewife), various elements were detected. In-air micro-analysis was useful for assessing the spatial distribution and content of particles in specimens from patients. Occupational exposure was not necessarily associated with deposition of particles in the lungs. Therefore, in the diagnosis of, elemental analysis of specimens by in-air micro-analysis could be useful for assessing exposure to particles objectively.

Theoretical Approach Of The Reduction Of Chromatic And Spherical Aberrations In An Acceleration Lens System For Hundreds Of keV Gaseous Ion Nanobeam

The focused gaseous ion beam (gas‐FIB) system composed of a series of electrostatic lenses, called “acceleration lens system”, has been developed to form nanobeams using gaseous ions generated from a plasma ion source. Ion beams are accelerated and focused simultaneously by a pair of electrodes. A new all‐in‐one compact acceleration system including an acceleration tube is now under development to form 300 keV ion nanobeam. Chromatic and spherical aberrations are, however, hindrance to form nanobeams with their smaller sizes in diameter. A deceleration lens, which performs like a defocusing lens, was theoretically introduced to downstream of the present acceleration lens system to reduce the aberrations. Ion beam optics simulations were carried out to show that this aberration reduction technique is effective to reduce chromatic and spherical aberrations. As a result, we reduced the chromatic aberration coefficient by 26%, the spherical aberration coefficient by 17% and a beam diameter by 17%, with the de...