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Okuda M, Ogawa N, Takeguchi M, Hashimoto A, Tagaya M, Chen S, Hanagata N, Ikoma T. Minerals and aligned collagen fibrils in tilapia fish scales: structural analysis using dark-field and energy-filtered transmission electron microscopy and electron tomography. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2011; 17:788-798. [PMID: 21899811 DOI: 10.1017/s1431927611011949] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The mineralized structure of aligned collagen fibrils in a tilapia fish scale was investigated using transmission electron microscopy (TEM) techniques after a thin sample was prepared using aqueous techniques. Electron diffraction and electron energy loss spectroscopy data indicated that a mineralized internal layer consisting of aligned collagen fibrils contains hydroxyapatite crystals. Bright-field imaging, dark-field imaging, and energy-filtered TEM showed that the hydroxyapatite was mainly distributed in the hole zones of the aligned collagen fibrils structure, while needle-like materials composed of calcium compounds including hydroxyapatite existed in the mineralized internal layer. Dark-field imaging and three-dimensional observation using electron tomography revealed that hydroxyapatite and needle-like materials were mainly found in the matrix between the collagen fibrils. It was observed that hydroxyapatite and needle-like materials were preferentially distributed on the surface of the hole zones in the aligned collagen fibrils structure and in the matrix between the collagen fibrils in the mineralized internal layer of the scale.
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102
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Hashimoto A, Mitsuishi K, Shimojo M, Zhu Y, Takeguchi M. Experimental examination of the characteristics of bright-field scanning confocal electron microscopy images. JOURNAL OF ELECTRON MICROSCOPY 2011; 60:227-234. [PMID: 21486860 DOI: 10.1093/jmicro/dfr013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We experimentally examined the characteristics of bright-field (BF) scanning confocal electron microscopy (SCEM) images by changing the observation conditions and comparing the images with those obtained by BF transmission electron microscopy (TEM) and BF scanning TEM (STEM) modes. The observation of 5-nm-diameter Au nanoparticles demonstrated that BF-SCEM produces object elongation of more than 2000 nm along the optical axis, as do BF-TEM and BF-STEM. We demonstrated the relationship between elongation length and geometric effects such as convergence and collection angles of a probe and the lateral size of an object; the relationship is consistent with previous theoretical prediction. Further, we observed interesting features that are seen only in the BF-SCEM images; the film contrast was strongly enhanced, compared with that of BF-STEM. In addition, a bright contrast appeared around the object position in the elongated images. Using this characteristic, we could determine the object position and structure.
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Mitsuishi K, Hashimoto A, Takeguchi M, Shimojo M, Ishizuka K. Imaging properties of bright-field and annular-dark-field scanning confocal electron microscopy. Ultramicroscopy 2010; 111:20-6. [DOI: 10.1016/j.ultramic.2010.08.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 07/14/2010] [Accepted: 08/24/2010] [Indexed: 11/28/2022]
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104
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Honda M, Nakamura T, Hori Y, Shionoya Y, Nakada A, Sato T, Yamamoto K, Kobayashi T, Shimada H, Kida N, Hashimoto A, Hashimoto Y. Process of healing of mucosal defects in the esophagus after endoscopic mucosal resection: histological evaluation in a dog model. Endoscopy 2010; 42:1092-5. [PMID: 21038294 DOI: 10.1055/s-0030-1255741] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND AND STUDY AIMS Resection of a large amount of the esophageal mucosa often causes esophageal ulcer and postoperative stricture. The aim of this study was to evaluate the process of healing of defects in the esophageal mucosa after endoscopic mucosal resection (EMR). MATERIALS AND METHODS Cap-assisted EMR was performed in the thoracic esophagus of six beagle dogs to prepare mucosal defects with a diameter ranging from 15 to 18 mm. The process of mucosal healing was assessed histologically immediately after EMR, and on postoperative day (POD) 2, 4, 7, 14, and 28. RESULTS Immediately after EMR, a thin layer of the submucosa remained in the mucosal defect, and no damage to the muscularis propria was evident. Ulcer formation and inflammatory cell invasion were observed in the remaining submucosa on POD 2 and 4. Angiogenesis and collagen fiber hyperplasia were observed after POD 7. Complete epithelialization of the ulcer was observed on POD 28. In the muscularis propria, further destruction and atrophy were evident after POD 7. Fibrosis of the muscularis propria was observed on POD 28. CONCLUSION In the esophageal wall after epithelial loss resulting from EMR, atrophy and fibrosis of the muscularis propria remain even after epithelialization.
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105
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Hashimoto A, Kakigi R. P33-19 Competition between attention and perception in visual evoked fields. Clin Neurophysiol 2010. [DOI: 10.1016/s1388-2457(10)61238-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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106
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Okuda M, Takeguchi M, Zhu Y, Hashimoto A, Ogawa N, Tagaya M, Chen S, Hanagata N, Ikoma T. Structural analysis of rattle-type hollow mesoporous silica spheres using electron tomography and energy filtered imaging. SURF INTERFACE ANAL 2010. [DOI: 10.1002/sia.3572] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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107
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Hashimoto A, Shimojo M, Mitsuishi K, Takeguchi M. Three-dimensional optical sectioning by scanning confocal electron microscopy with a stage-scanning system. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2010; 16:233-238. [PMID: 20350339 DOI: 10.1017/s1431927610000127] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We evaluated the depth resolution of annular dark-field (ADF) scanning confocal electron microscopy (SCEM) with a stage-scanning system by observation of nanoparticles. ADF-SCEM is a three-dimensional (3D) imaging technique that we recently proposed. An ADF-SCEM instrument involves a pinhole aperture before a detector for rejecting electrons from the out-of-focal plane in a specimen and an annular aperture under the specimen for collecting only scattered electrons. The stage-scanning system enables us to directly obtain optical slice images perpendicular and parallel to an optical axis at a desired position. In particular, the parallel slices visualize the elongation of nanoparticles along the optical axis, which depends on the depth resolution. ADF-SCEM effectively reduced the elongation length of the nanoparticles sufficiently to demonstrate depth sectioning, in comparison with scanning transmission electron microscopy and bright-field SCEM. The experimentally obtained length was nearly equal to the theoretically estimated one from the probe size considering the experimental conditions. Furthermore, we applied this ADF-SCEM technique to analysis of the 3D position of catalytic nanoparticles on carbon nanostructures.
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108
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Wang P, Behan G, Takeguchi M, Hashimoto A, Mitsuishi K, Shimojo M, Kirkland AI, Nellist PD. Nanoscale energy-filtered scanning confocal electron microscopy using a double-aberration-corrected transmission electron microscope. PHYSICAL REVIEW LETTERS 2010; 104:200801. [PMID: 20867018 DOI: 10.1103/physrevlett.104.200801] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Indexed: 05/08/2023]
Abstract
We demonstrate that a transmission electron microscope fitted with two spherical-aberration correctors can be operated as an energy-filtered scanning confocal electron microscope. A method for establishing this mode is described and initial results showing 3D chemical mapping with nanoscale sensitivity to height and thickness changes in a carbon film are presented. Importantly, uncorrected chromatic aberration does not limit the depth resolution of this technique and moreover performs an energy-filtering role, which is explained in terms of a combined depth and energy-loss response function.
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Matsushita R, Hashimoto A, Tomita T, Yoshitawa H, Tanaka S, Endo H, Hirohata S. Enhanced expression of mRNA for FK506-binding protein 5 in bone marrow CD34 positive cells in patients with rheumatoid arthritis. Clin Exp Rheumatol 2010; 28:87-90. [PMID: 20346245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE Recent studies have disclosed that several genes are up-regulated in bone marrow (BM) mononuclear cells from rheumatoid arthritis (RA) patients. However, it remains unclear whether such abnormalities result from systemic inflammation or from abnormalities at stem cell level. The current study therefore examined the expression of several representative genes, including amphiregulin (AREG), chemokine receptor 4 (CXCR4), and FK506-binding protein 5 (FKBP5) in RA BM CD34+ cells. METHODS BM samples were obtained from 52 patients with RA and 35 patients with osteroarthritis (OA) during joint operations. CD34+ cells were purified from the BM mononuclear cells by positive selection with magnetic beads. The mRNA expression for AREG, CXCR4, and FKBP5 was measured using quantitative real-time PCR. RESULTS The expression of mRNA for FKBP5, but not that of AREG or CXCR4, was significantly higher in RA BM CD34+ cells than in OA BM CD34+ cells. The FKBP5 mRNA expression level was not correlated with serum CRP or treatment. In addition, tumour necrosis factor-alpha did not enhance the expression of FKBP5 mRNA in BM CD34+ cells from healthy donors. CONCLUSION The results suggest that the enhanced expression of FKBP5 in BM CD34+ cells might be an intrinsic abnormality of RA BM CD34+ cells, whereas the enhanced expression of AREG and CXCR4 in BM mononuclear cells might be secondary to systemic inflammation.
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Okuda M, Takeguchi M, Ruairc OO, Tagaya M, Zhu Y, Hashimoto A, Hanagata N, Schmitt W, Ikoma T. Structural analysis of hydroxyapatite coating on magnetite nanoparticles using energy filter imaging and electron tomography. JOURNAL OF ELECTRON MICROSCOPY 2009; 59:173-179. [PMID: 19897510 DOI: 10.1093/jmicro/dfp055] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Magnetic nanoparticle (MNP) composites with a magnetite (Fe(3)O(4)) core and a hydroxyapatite (HAp, Ca(10)(PO(4))(6)(OH)(2)) coating were prepared using a precipitation method and a subsequent hydrothermal treatment. The hydrothermal treatment diminished the lepidocrocite layer on the magnetite, enhanced the crystal growth of HAp and dissolved the MNPs. The divalent iron ions dissolved into solvent were not substituted for the HAp lattice. The three-dimensional (3D) nanostructure, the crystal morphology of HAp covered with the MNPs and the interfacial nanostructure of magnetite/HAp were analyzed using an energy-filter transmission electron microscopy (EF-TEM) and visualized by computer tomography in transmission electron microscopy (TEM). EF-TEM and 3D reconstruction images using a tilted series of high-angle annular dark-field images showed that the needlelike HAp nanocrystals covered with a magnetite core and the crystal growth of HAp attached to the magnetite surface was inhibited as a result of the lower density of the nucleation site of the lepidocrocite layer. The dissolution of iron ion from MNPs and the interfacial interaction of HAp and magnetite could cause the needlelike morphology of HAp nanocrystals.
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Fujimura T, Okuyama R, Ohtani T, Ito Y, Haga T, Hashimoto A, Aiba S. Perilesional treatment of metastatic melanoma with interferon-β. Clin Exp Dermatol 2009; 34:793-9. [DOI: 10.1111/j.1365-2230.2009.03207.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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112
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Yanase Y, Nakamura M, Uehara M, Tabuchi M, Baba T, Kanki K, Hashimoto A, Higami T. [Off-pump coronary artery bypass surgery for the ischemic cardiomyopathy patient with moderate mitral regurgitation and stenosis of bilateral vertebral arteries]. KYOBU GEKA. THE JAPANESE JOURNAL OF THORACIC SURGERY 2009; 62:875-879. [PMID: 19764492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report a 71-year-old man who had severe coronary and cerebral vascular disease with moderate mitral regurgitation (MR). Left ventricular reconstruction and mitral valve surgery were considered for poor left ventricular function and dilatation with MR. However, low blood pressure during cardiac arrest was risk for stroke due to severe stenosis of bilateral vertebral arteries. The myocardial viability of the anterior wall and inferior wall was confirmed by thallium-201 rest-redistribution single photon emission computed tomography (SPECT). Therefore, off-pump coronary artery bypass grafting (OPCAB) was selected for the patient. Only three Lima sutures were used for keeping the optimal heart position. Coronary anastomoses were done in sequence right gastroepiploic artery (RGEA)-#4 posterior descending (PD), left internal thoracic artery (LITA)-#9-#14 (sequential), RITA-#8 left anterior descending (LAD). No neurological complication occurred postoperatively. Left ventricular function and MR gradually improved. Final ejection fraction (EF) is 51% and MR is trivial. This case demonstrated improvement of MR by only revascularization according to preoperative viability assessment.
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Okuda M, Takeguchi M, Tagaya M, Tonegawa T, Hashimoto A, Hanagata N, Ikoma T. Elemental distribution analysis of type I collagen fibrils in tilapia fish scale with energy-filtered transmission electron microscope. Micron 2009; 40:665-8. [DOI: 10.1016/j.micron.2009.04.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2009] [Accepted: 04/06/2009] [Indexed: 10/20/2022]
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114
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Suzuki A, Hashimoto A, Nojima M, Owari M, Nihei Y. Holographic imaging of TiO2(110) surface structure by differential photoelectron holography. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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115
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Kisaka Y, Hashimoto A, Suzuki A, Miyasaka S, Nojima M, Owari M, Nihei Y. Study on dynamics of surface structure by rapid and time-resolved X-ray photoelectron diffraction. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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116
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Hashimoto A, Suzuki A, Kisaka Y, Miyasaka S, Nojima M, Owari M, Nihei Y. Differential photoelectron holography of Cu(100) surface using laboratory-level X-ray sources. SURF INTERFACE ANAL 2008. [DOI: 10.1002/sia.2958] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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117
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Hashimoto A, Hashimoto S, Ogawa E, Hirose M, Morishige M, Menju T, Shibuya M, Sabe H. 54 POSTER Common usage of the GEP100-Arf6-AMAP1 pathway in tumor invasion, angiogenesis and vascular permeability. EJC Suppl 2008. [DOI: 10.1016/s1359-6349(08)71986-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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118
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Takeguchi M, Hashimoto A, Shimojo M, Mitsuishi K, Furuya K. Development of a stage-scanning system for high-resolution confocal STEM. JOURNAL OF ELECTRON MICROSCOPY 2008; 57:123-7. [PMID: 18603569 DOI: 10.1093/jmicro/dfn010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A stage-scanning system is composed of a specially designed transmission electron microscopy specimen holder equipped with a piezo-driven specimen stage, power supplier and control software. This system enables the specimen to be scanned three-dimensionally, and therefore confocal scanning transmission electron microscopy (STEM) can be performed with a fixed electron-optics configuration. It is demonstrated that stage-scanning confocal STEM images can be obtained with the lateral atomic resolution and the specimen can be moved three-dimensionally with high precision.
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Suzuki S, Nakajima A, Sakai M, Sakurada Y, Yoshida N, Hashimoto A, Kameshima Y, Okada K. Slipping and Rolling Ratio of Sliding Acceleration for a Water Droplet Sliding on Fluoroalkylsilane Coatings of Different Roughness. CHEM LETT 2008. [DOI: 10.1246/cl.2008.58] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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120
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Hirata J, Oya M, Kotani J, Yamada T, Hashimoto A, Ueda T, Terashima M, Marukawa S. Association between ATP production and oxidative mtDNA damage through mitochondrial respiratory chain in the rat caecal ligation and puncture heart injury model. Crit Care 2008. [PMCID: PMC4088758 DOI: 10.1186/cc6608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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121
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Suzuki S, Nakajima A, Yoshida N, Sakai M, Hashimoto A, Kameshima Y, Okada K. Freezing of water droplets on silicon surfaces coated with various silanes. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.07.066] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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122
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Suzuki S, Nakajima A, Yoshida N, Sakai M, Hashimoto A, Kameshima Y, Okada K. Hydrophobicity and freezing of a water droplet on fluoroalkylsilane coatings with different roughnesses. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:8674-7. [PMID: 17637012 DOI: 10.1021/la701077p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Smooth (Ra approximately 0.1 nm) and rough (Ra approximately 20 nm) coatings of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (FAS-17) were prepared by controlling process conditions. The water contact angles for the smooth and rough coatings were similar (107 degrees and 110 degrees, respectively), but their sliding angles differed considerably (10 degrees and 27 degrees, respectively). The surface potential on the smooth coating, assessed using Kelvin force microscopy, showed a sharp distribution, but that on the rough coating ranged widely, implying large chemical heterogeneity including residual SiOH groups. The freezing temperature of a supercooled water droplet on the rough coating was higher than that on the smooth coating.
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Nakajima A, Imase A, Suzuki S, Yoshida N, Sakai M, Hashimoto A, Kameshima Y, Toshiyoshi H, Okada K. Effect of Electrification Conditions on the Freezing of Supercooled Water Droplets on a Hydrophobic Coating. CHEM LETT 2007. [DOI: 10.1246/cl.2007.1020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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124
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Takase H, Hashimoto A, Okutsu R, Hirose Y, Ito H, Imaizumi T, Miyakoda G, Mori T. Anti-atherosclerotic effect of cilostazol in apolipoprotein-E knockout mice. ACTA ACUST UNITED AC 2007; 57:185-91. [PMID: 17515288 DOI: 10.1055/s-0031-1296604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
To investigate whether cilostazol (CAS 73963-72-1), a selective phosphodiesterase 3 inhibitor, reduces the progression of atherogenic diet-induced atherosclerosis, cilostazol was orally administered twice a day for 4 weeks to male apolipoprotein-E knockout (ApoE KO) mice. In serial sections of the aortic root, the atherosclerotic lesion ratios in the cilostazol-treated groups (32.5 +/- 3.3% for 100 mg/kg, 29.0 +/- 2.9% for 300 mg/kg) were significantly and dose-dependently smaller than that of the control group (40.2 +/- 3.7%). Cilostazol also significantly reduced the expression of vascular cell adhesion molecule-1 (VCAM-1) and monocyte/macrophage accumulation in the aortic root and increased high-density lipoprotein(HDL) cholesterol levels in plasma. These results suggest that cilostazol suppresses the progression of atherosclerosis in ApoE KO mice by inhibiting adhesionand infiltration of monocytes and reducing cholesterol accumulation in atherosclerotic lesion.
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Sumi M, Sata M, Hashimoto A, Imaizumi T, Yanaga K, Ohki T, Mori T, Nagai R. OPC-28326, a selective femoral arterial vasodilator, augments ischemia induced angiogenesis. Biomed Pharmacother 2007; 61:209-15. [PMID: 17223008 DOI: 10.1016/j.biopha.2006.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 12/04/2006] [Indexed: 09/30/2022] Open
Abstract
OPC-28326, 4-(N-methyl-2-phenylethylamino)-1-(3,5-dimethyl-4-propionyl-aminobenzoyl) piperidine hydrochloride monohydrate, is a newly developed selective peripheral vasodilator and increases blood flow to lower extremities with alpha2-adrenergic antagonist property. Here, we investigated the effect of OPC-28326 on ischemia-induced angiogenesis. OPC-28326 enhanced tube formation by human aortic endothelial cells (HAECs). Moreover, OPC-28326 enhanced the number of microvessels sprouting from aortic rings embedded in collagen gel. OPC-28326 markedly induced phosphorylation of endothelial nitric oxide synthase (eNOS) in HAECs via phosphatidylinositol-3 kinase PI3K/Akt (PI3K/Akt) pathway. Next, the angiogenic effect of OPC-28326 was evaluated in a mouse hindlimb ischemia model. Blood flow recovery to the ischemic leg was significantly enhanced by OPC-28326. Furthermore, anti-CD31 immunostaining revealed that OPC-28326 increased capillary density in the ischemic muscle. However, OPC-28326 failed to promote blood flow recovery in ischemic hindlimb in eNOS-deficient mice. These results suggest that OPC-28326 promotes angiogenesis, which was associated with activation of eNOS via PI3K/Akt pathway. OPC-28326 might be promising to treat patients with ischemic vascular diseases.
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