Silver microcoil is fabricated through a biotemplating process combined with electroless plating. Spiral vessels in Lotus root are employed as a biotemplate because of their left-handed coil structure. The silver microcoil exhibits a solenoidal microcoil showing self-inductance in the level of picohenry, which could be applied for electromagnetic-responsive materials in the high-frequency region such as millimeter waves or terahertz waves.

At axon initial segments and nodes of Ranvier in neurons, the spectrin membrane skeleton plays roles in physically stabilizing the plasma membrane integrity and in clustering voltage-gated sodium channels for proper conduction of the action potential. ␤IV-Spectrin, an essential component of the membrane skeleton at these sites, has an N-terminal-truncated isoform, ⌺6, which is expressed at much higher levels than the full-length isoform ⌺1. To investigate the role of ␤IV-spectrin ⌺6, we generated ⌺1-deficient mice with a normal level of ⌺6 expression (⌺1 ؊/؊ mice), and compared their phenotypes with those of previously generated mice lacking both ⌺1 and ⌺6 (⌺1⌺6 ؊/؊ mice). The gross neurological defects observed in ⌺1⌺6 ؊/؊ mice, such as hindleg contraction, were apparently ameliorated in ⌺1 ؊/؊ mice. At cellular levels, ⌺1⌺6 ؊/؊ and ⌺1 ؊/؊ neurons similarly exhibited waving and swelling of the plasma membrane at axon initial segments and nodes of Ranvier. By contrast, the levels of ankyrin G and voltage-gated sodium channels at these sites, which are significantly reduced in ⌺1⌺6 ؊/؊ mice, were substantially recovered in ⌺1 ؊/؊ mice. We conclude that the truncated ␤IV-spectrin isoform ⌺6 plays a specific role in clustering voltage-gated sodium channels, whereas it is dispensable for membrane stabilization at axon initial segments and nodes of Ranvier.The spectrin membrane skeleton is a polygonal cytoskeletal meshwork attached to the cytoplasmic face of the plasma membrane (1). The basic unit of the spectrin skeleton is a heterotetramer of two ␣-spectrin and two ␤-spectrin proteins. ␤-Spectrin has an N-terminal actin-binding domain, and the spectrin tetramers are bound to one another indirectly via short actin filaments to form the meshwork. ␤-Spectrin also binds to a membrane adaptor protein ankyrin via the spectrin repeat 15 (2), thereby allowing the attachment of the spectrin-actin meshwork to the plasma membrane. Two major roles are known for the spectrin skeleton. One is to physically stabilize the plasma membrane integrity. In hereditary diseases with mutations in the erythrocyte-specific ␣I-and ␤I-spectrin genes, the erythrocyte membrane becomes fragile, resulting in elliptocytosis and spherocytosis, and eventually hemolytic anemia (3). The second role is to cluster specific integral membrane proteins at high density in specialized regions of the plasma membrane. For example, ␣II-and ␤II-spectrins stabilize the clustering of Na ϩ /K ϩ -ATPase at cell-cell contact sites in polarized epithelial cells through ankyrin B-mediated interaction with Na ϩ /K ϩ

Microstructures in nature are ultrafine and ordered in biological roles, which have attracted material scientists. Spirulina forms three-dimensional helical microstructure, one of remarkable features in nature beyond our current processing technology such as lithography in terms of mass-productivity and structural multiplicity. Spirulina varies its diameter, helical pitch, and/or length against growing environment. This unique helix is suggestive of a tiny electromagnetic coil, if composed of electro-conductive metal, which brought us main concept of this work. Here, we describe the biotemplating process onto Spirulina surface to fabricate metal microcoils. Structural parameters of the microcoil can be controlled by the cultivation conditions of Spirulina template and also purely one-handed microcoil can be fabricated. A microcoil dispersion sheet exhibited optically active response attributed to structural resonance in terahertz-wave region.

SummaryVascular endothelial growth factor (VEGF) is a mitogen for endothelial cells. We have studied the production of VEGF by human macrophages in response to lipopolysaccharide (LPS). Macrophages stimulated with LPS expressed VEGF mRNA and protein in concentration- and time-dependent manners. The LPS-induced expression of VEGF was inhibited by cycloheximide pretreatment, which suggested that synthesis of certain factor(s) is required for the LPS activity. The induction of VEGF was also suppressed by SB203580, an inhibitor of p38 mitogen-activated protein (MAP) kinase. These results suggest that the LPS-induced VEGF expression depends on the p38-mediated expression of c-Jun, which constitutes the AP-1 complex and binds to the AP-1 site in the VEGF promoter. Pretreatment of the cells with dexamethasone did not affect the LPS-induced upregulation of VEGF mRNA but strongly inhibited VEGF protein production, and the involvement of posttranscriptional regulation on VEGF expression by dexamethasone was suggested. The conditioned medium of LPS-stimulated macrophages enhanced the growth of cultured endothelial cells and it was inhibited by an antibody against VEGF. We conclude that macrophages produce VEGF in response to the stimulation with LPS, which may be partly mediated by the p38 MAP kinase pathway.

Deep levels in iron-doped n-type silicon have been investigated by deep-level transient spectroscopy (DLTS). Three deep levels of Ec−0.29 eV (E1), Ec−0.36 eV (E2), and Ec−0.48 eV (E3) were observed. The concentration of E1 and E2 levels increased during the storage at room temperature. The depth profile of the E3 level concentration indicates the out-diffusion and precipitation of the defects related to the E3 level. In addition, after annealing at 80 °C for 30 min, the E2 and E3 concentrations decreased and then recovered at room temperature. These results suggest that the defects related to these levels are mobile during quenching and storage at room temperature. The temperature dependence of the E3 level concentration shows a formation energy of about 2 eV, which is smaller than that of interstitial iron, and the E3 level concentration is two orders of magnitude lower than the concentration of interstitial iron. The origins of these levels are probably loosely associated iron-related complexes such as iron-acceptor pairs.

SummarySurface coverage with autogeneous endothelial cells is effective in reducing thrombogenicity of an artificial vascular graft, but procedure for obtaining the cells is invasive for patients. The purpose of this study was to establish cultures of human endothelial cells separated from a small piece of subcutaneous fat tissue. A piece of tissue weighing about 10 mg was obtained from subcutaneous fat using a biopsy needle, and treated with collagenase and dispase. Microvascular endothelial cells were selected and other types of cells contaminating the cultures were eliminated by scraping with a needle under a microscope. The yield of the cells was 8362 ± 4264/10 mg of subcutaneous fat (n = 7). The cultures reached confluence in about 2 weeks. The cells were positive for von Willebrand factor, P-selectin, and uptake of acetylated low density lipoprotein. The cells produced 15.9 ± 3.3 ng/mg cell protein/h of 6-ketoprostaglandin F1α (n = 5) when stimulated with thrombin. Thrombin also stimulated the production of platelet-activating factor: 7653 ± 4297 dpm/106 cells (n = 5). Endothelin-1 accumulation in the medium of unstimulated endothelial cells was 0.54 ± 0.16 ng/mg cell protein/10 h (n = 8). As a preliminary experiment for graft seeding, the cells were also cultured on pieces of a gelatin-coated Dacron graft, and scanning electron microscopy revealed the surface coverage of the graft. We herein described about successful culture of human microvascular endothelial cells from subcutaneous fat tissue obtained using a biopsy needle. The cultured cells may be applicable to a seeded vascular graft.

No abstract

No abstract