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Biomedical subjects

Yoshio Bando

Publications and source records attributed to Yoshio Bando.

At least 55 records · Page 3Linked to original sources
PubMed2005

Growth of self-organized hierarchical ZnO nanoarchitectures by a simple In/In2S3 controlled thermal evaporation process.

Novel hierarchical ZnO nanoarchitectures, such as microtrepangs, microbelts, nanoflowers, nanocombs, nanowheels, and nanofans assembled by ZnO nanocones, nanobowling pins, nanobottles, nanoarrows, and nanonails, have had their growth controlled by the thermal evaporation of Zn and a mixture of In and In2S3. Both the morphologies of the products and their construction units could be efficiently controlled by simple adjustment of the weight ratio of In/In2S3. The phase structure, morphologies, and photoluminescence properties of the ZnO products were investigated by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. These novel hierarchical ZnO nanoarchitectures may be attractive building blocks for creating optical or other nanodevices.

Journal Article↗
PubMed2005

Synthesis and evolution of novel hollow ZnO urchins by a simple thermal evaporation process.

Delicate hollow ZnO urchins have been fabricated by thermal evaporation of metallic zinc powders in a tube furnace without the use of additive, high temperature, or low pressure. The phase transformation, morphologies, and photoluminescence evolution of the ZnO products were carefully studied and investigated with X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and photoluminescence (PL) spectra. These studies indicated that the growth of hollow ZnO urchins involves the vaporization of Zn powder, solidification of liquid droplets, surface oxidation, sublimation, and self-catalytic growth of one-dimensional nanowires.

Chemistry, Physical↗
PubMed2005

Fluorination and electrical conductivity of BN nanotubes.

Fluorination of BN nanotubes has been performed using a catalytic growth method, which leads to the appearance of markedly curved fluorine-doped BN sheets and converts originally insulating BN nanotubes to semiconductors, as confirmed by the comparative electron transport four-probe measurements on doped and undoped individual BN nanotubes.

Journal Article↗
PubMed2005

Differential expression of protease M/neurosin in oligodendrocytes and their progenitors in an animal model of multiple sclerosis.

To determine the possible involvement of protease M/neurosin in demyelinating diseases of the CNS, we examined its expression in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), a recognized animal model of multiple sclerosis (MS). In situ hybridization, immunohistochemistry and quantitative real-time polymerase chain reaction (PCR) demonstrated that EAE caused an increase in the expression of protease M/neurosin mRNA and its protein product throughout the white and gray matter surrounding demyelinating lesions. Combined in situ hybridization and immunohistochemistry demonstrated that most of the cells expressing protease M/neurosin mRNA within control spinal cord showed immunoreactivity for CNPase or NG2, cell-specific markers for oligodendrocytes and their progenitors, respectively. In the spinal cord from mice with EAE, the expression of protease M/neurosin mRNA in CNPase-positive cells appeared to be increased while double-labeled cells positive for protease M/neurosin mRNA and NG2 were rarely found in areas associated with demyelinating lesions. Although a prominent accumulation of inflammatory cells including T-cells was observed in the vicinity of demyelinated lesions, these cells were not associated with protease M/neurosin mRNA expression. The levels of protease M/neurosin mRNA expression were unchanged in the spleen and even decreased in the thymus during the course of EAE. These observations suggest that the differential expression of protease M/neurosin in mature oligodendrocytes and their progenitors is involved in the pathogenesis of MS and EAE.

Animals↗
PubMed2005

Structural features of titanate nanotubes/nanobelts revealed by Raman, X-ray absorption fine structure and electron diffraction characterizations.

High-purity nanotubes and nanobelts could be controllably obtained in hydrothermal treatments of anatase TiO(2) in concentrated NaOH solution depending on treating temperature and duration. Their structural features were studied employing X-ray diffraction, Raman, X-ray absorption fine structure, and electron diffraction characterizations. The results reveal that both the nanotubes and nanobelts might be of layered titanate structure. The similarity and difference among the nanotubes/nanobelts and other bulk titanates represented by trititanate H(2)Ti(3)O(7) and lepidocrocite-type H(0.7)Ti(1.825) square(0.175)O(4.0).H(2)O were also presented.

Journal Article↗
PubMed2005

Unconventional gallium oxide nanowires.

Zigzag and helical beta-Ga(2)O(3) one-dimensional nanostructures were produced by thermal evaporation of gallium oxide in the presence of gallium nitride. High-resolution TEM analysis indicates that each individual zigzag nanostructure has a periodic arrangement of three distinct blocks: two structurally perfect blocks mirrored with respect to each other on the (002) plane, and one stacking-fault-rich block sandwiched between them. In a zigzag nanostructure, the growth orientation of a beta-Ga(2)O(3) crystal changes alternately in three blocks. The zigzag nanostructure as a whole has the [001] axial direction. In addition to zigzag nanostructures, single-crystalline helical nanowires were also obtained.

Catalysis↗
PubMed2005

A liquid-Ga-filled carbon nanotube: a miniaturized temperature sensor and electrical switch.

Temperature control on the nanometer scale is a challenging task in many physical, chemical, and material science applications where small experimental volumes with high temperature gradients are used. The crucial difficulty is reducing the size of temperature sensors while keeping their sensitivity, working temperature range, and, most importantly, their simplicity and accuracy of temperature reading. In this work, we demonstrate the ultimate miniaturization of the classic thermometer using an expanding column of liquid gallium inside a multi-walled C nanotube for precise temperature measurements. We report that electrical conductivity through unfilled nanotube regions is diffusive with a resistance per unit length of approximately 10 kOmega microm(-1), whereas Ga-filled segments of the nanotube show metallic behavior with a low resistance of approximately 100 Omega microm(-1). No noticeable Schottky barrier exists between the nanotube carbon shell and the inner Ga filling. Based on these findings, an individual carbon nanotube partially filled with liquid Ga is used as a temperature sensor and/or switch. The nanotube's electrical resistance decreases linearly with increasing temperature as the metallic Ga column expands inside the tube channel. In addition, the tube resistance drops sharply when two encapsulated Ga columns approaching each other meet inside the nanotube, producing a switching action that can occur at any predetermined temperature, as the Ga column position inside the nanotube can be effectively pre-adjusted by nanoindentation using an atomic force microscope.

Biosensing Techniques↗
PubMed2005

Growth of semiconducting GaN hollow spheres and nanotubes with very thin shells via a controllable liquid gallium-gas interface chemical reaction.

An in situ liquid gallium-gas interface chemical reaction route has been developed to synthesize semiconducting hollow GaN nanospheres with very small shell size by carefully controlling the synthesis temperature and the ammonia reaction gas partial pressure. In this process the gallium droplet does not act as a catalyst but rather as a reactant and a template for the formation of hollow GaN structures. The diameter of the synthesized hollow GaN spheres is typically 20-25 nm and the shell thickness is 3.5-4.5 nm. The GaN nanotubes obtained at higher synthesis temperatures have a length of several hundreds of nanometers and a wall thickness of 3.5-5.0 nm. Both the hollow GaN spheres and nanotubes are polycrystalline and are composed of very fine GaN nanocrystalline particles with a diameter of 3.0-3.5 nm. The room-temperature photoluminescence (PL) spectra for the synthesized hollow GaN spheres and nanotubes, which have a narrow size distribution, display a sharp, blue-shifted band-edge emission peak at 3.52 eV (352 nm) due to quantum size effects.

Ammonia↗
PubMed2005

RA410/Sly1 suppresses MPP+ and 6-hydroxydopamine-induced cell death in SH-SY5Y cells.

Parkinson's disease is characterized by selective loss of dopaminergic neurons in the substantia nigra. However, its associated cell death mechanism remains unknown. 1-Methyl-4-phenil-pyridinium (MPP+) and 6-hydroxydopamine (6-OHDA) cause dopaminergic neuronal cell death. Both are widely used to model PD. We investigated the role of a vesicle-transport-related protein, RA410/Sly1, in SH-SY5Y cells to clarify the mechanism of cellular adaptation to MPP+ and 6-OHDA-induced stress. Antisense RA410/Sly1 transformants treated with these toxins displayed reduced viability in comparison with viability of wild-type or RA410/Sly1 sense transformants. Electron microscopy analysis indicated that the ER in MPP+-treated antisense RA410/Sly1 transformants was rapidly disrupted in comparison to wild-type or sense RNA transformants. Cell death induced by MPP+ and 6-OHDA was suppressed in RA410/Sly1 sense transformants through suppression of caspase-2, -3 and -9 activation. These results suggest that RA410/Sly1 plays an important cytoprotective role in MPP+ and 6-OHDA-induced cellular perturbation.

1-Methyl-4-phenylpyridinium↗
PubMed2005

Double-strand RNA dependent protein kinase (PKR) is involved in the extrastriatal degeneration in Parkinson's disease and Huntington's disease.

Double-strand RNA dependent protein kinase (PKR) plays an important role in control of cell death. We previously reported that activation of PKR is associated with hippocampal neuronal loss in Alzheimer's disease (AD). Recent studies have reported that Parkinson's (PD) and Huntington's (HD) disease brains displayed progressive hippocampal neuronal loss in extrastriatal degeneration. However, association between PKR and hippocampal neuronal loss in PD and HD brains is not known. In this report, brain tissues from patients with PD and HD displayed strong induction of phosphorylated-PKR (p-PKR) in hippocampal neurons. Immunoblotting analysis also demonstrated that levels of nuclear p-PKR in the hippocampus affected by these diseases were increased compared with age-matched disease controls. These results suggest that a close association exists between PKR and extrastriatal degeneration in PD and HD pathology.

Adult↗
PubMed2005

150-kDa oxygen-regulated protein attenuates myocardial ischemia-reperfusion injury in rat heart.

Early contractile dysfunction and the later death of cardiomyocytes are two major problems that can follow myocardial infarction or major cardiovascular surgery that demands ischemic arrest of the heart. Here, we found that 24 h of hypoxia and 1 h of reoxygenation induced the expression of the chaperone ORP150 in cultured rat cardiomyocytes. Inhibition of its induction using an adenovirus to express anti-sense ORP150 significantly enhanced the hypoxia-reoxygenation-induced cardiomyocyte death; cell death was reduced by overexpressing ORP150. Decreased levels of ORP150 expression also enhanced caspase-3 and -8 activation, cytochrome-c release, and DNA fragmentation, suggesting that this chaperone regulates apoptotic cell death. In contrast, increasing the expression of ORP150 in the cardiomyocytes had the opposite effect on the expression of these molecules. Moreover, apoptotic cell death initiated by myocardial ischemia-reperfusion (I/R) was significantly inhibited in vivo by transfecting an ORP150 expression plasmid into whole rat heart using the hemagglutinating virus of Japan (HVJ)-liposome method. Interestingly, ORP150 seemed to preserve calcium homeostasis in cardiomyocytes that underwent ischemia-reoxygenation in vitro. Calpain activity in the cardiomyocytes was enhanced by anti-sense ORP150 and suppressed by sense ORP150. Finally, we examined the functional recovery of rat hearts that overexpressed ORP150 or GFP protein and were subjected to I/R; we found that ORP150 preserved early contractile function after transient ischemia. Our results indicated cytoprotective roles for ORP150 in rat heart and suggested a therapeutic role for the protein both in preventing cardiomyocyte death and in preserving contractile function after ischemic damage.

Animals↗
PubMed2004

Possible involvement of the expression and phosphorylation of N-Myc in the induction of HMGA1a by hypoxia in the human neuroblastoma cell line.

Increased expression of N-Myc and expression of the high mobility group protein A1a (HMGA1a) were observed in the nuclei of SK-N-SH cells following exposure to hypoxia. These observations were accompanied by the appearance of additional high molecular weight bands, which were eliminated by pretreatment with alkaline phosphatase. Immunoprecipitation showed phosphorylation of serine, threonine and tyrosine residues of N-Myc in the nucleus. These results suggest that hypoxia-induced signals in SK-N-SH cells lead to persistent expression of HMGA1a, which may induce expression of the transcription factor N-Myc, and that phosphorylation at serine, threonine and tyrosine residues of N-Myc occurs at an early stage after stimulation. Such signal consolidation processes could play a role in neuronal survival after hypoxia in neurons.

Cell Hypoxia↗
PubMed2004

Transmission electron microscopy and electron diffraction study of the short-range ordering structure of alpha-LiFeO2.

The basic structure of alpha-LiFeO2, lithium iron oxide, is a cubic NaCl-type structure with a lattice constant of 0.42 nm; some short-range ordering characterized by octahedral clusters exists. The local structure of the short-range ordering was investigated by transmission electron microscopy and electron diffraction. A new short-range ordering structure was found in local areas. The local structure has a cubic lattice with a doubled lattice constant. The occupation factors of cations on Wyckoff sites 4(a) and 4(b) are different from those on 24(d) sites, but the stoichiometric composition in cubic clusters is the same as the macroscopic composition. The number of pairs in which iron cations exist in nearest-neighbor sites and next nearest-neighbor sites is reduced in the structure. This means that a magnetic interaction between the iron cations is reduced by cation ordering even without spin ordering at room temperature.

Journal Article↗