Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates genes involved in xenobiotic metabolism, cellular proliferation, and differentiation. Numerous xenobiotic and biological compounds are known to interact with AhR, but it remains an orphan receptor, because its physiological ligand is unknown. We identified AhR ligands in human urine using a yeast AhR signaling assay and then characterized their properties. Two ligands, indirubin and indigo, were both present at average concentrations of ϳ0.2 nM in the urine of normal donors. Indirubin was also detected in fetal bovine serum and contributed half of the total AhR ligand activity. The activities of indirubin and indigo were comparable with or more potent than that of the archetypal ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin, in yeast AhR activation assays. We suggest that the endogenous levels and potencies of indirubin and indigo are such that they activate AhR-mediated signaling mechanisms in vivo. AhR,1 also called the dioxin receptor, is a ligand-activated transcription factor that is present in most cell and tissue types of the body (1). AhR-mediated signaling is required for potent xenobiotic ligands such as TCDD and polychlorinated biphenyls to produce toxic responses (2, 3). Toxic effects that are linked to xenobiotic AhR ligand exposures in animals include cancers, reproductive impairment, endometriosis, birth defects, and immunological impairment (4 -6). The toxic potential of xenobiotic AhR ligands is currently a major concern for regulatory agencies that are responsible for protecting public and environmental health. Although numerous xenobiotic ligands for AhR have been identified, the AhR is considered to be an orphan receptor, because its physiological ligand(s) and its function are not known. Tryptophan and other indole-containing compounds (7-9), bilirubin (10), 7-ketocholesterol (11), lipoxin A4 (12), flavones, and related compounds (13) interact with AhR to produce activation or inhibition of signal transduction. In general, the low levels, lack of potency, and restricted distribution of these compounds make them unlikely candidates as major regulators of AhR signaling in most tissue types. We reasoned that human urine might be a good place to search for endogenous AhR ligands, and we developed a methodology to detect and isolate such compounds. EXPERIMENTAL PROCEDURESMaterials-Blue rayon was kindly provided by Dr. Hayatsu (Okayama University, Okayama City, Japan). General chemicals, essentially analytical grade, were purchased from Wako (Kyoto, Japan). TCDD was purchased from CIL (Andover, MA, USA). Indigo and ␤-glucuronidase were purchased from Sigma. Indirubin was synthesized as described in Hoessel et al. (14). Indigo and indirubin were further purified by HPLC before use.Yeast Assay for AhR Ligand Activity-The assay procedure was essentially as described by Miller (15). The yeast strain YCM3 was grown overnight at 30°C in synthetic glucose medium lacking tryptophan. Test chemicals (dissolved in Me 2 SO...

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Human olfactory ensheathing cells (OECs) were prepared from adult human olfactory nerves, which were removed during surgery for frontal base tumors, and were transplanted into the demyelinated spinal cord of immunosuppressed adult rats. Extensive remyelination was observed in the lesion site: In situ hybridization using a human DNA probe (COT-1) indicated a similar number of COT-1positive cells and OEC nuclei within the repaired lesion. The myelination was of a peripheral type with large nuclei and cytoplasmic regions surrounding the axons, characteristic of Schwann cell and OEC remyelination. These results provide evidence that adult human OECs are able to produce Schwann cell-like myelin sheaths around demyelinated axons in the adult mammalian CNS in vivo.

Upon forming a solid solution between CuGaS2 and ZnS, we have successfully developed a highly active (CuGa)(1-x)Zn(2x)S2 photocatalyst for H2 evolution in the presence of sacrificial reagents under visible light irradiation. The Ru-loaded (CuGa)0.8Zn0.4S2 functioned as a H2-evolving photocatalyst in a Z-scheme system with BiVO4 of an O2-evolving photocatalyst and Co complexes of an electron mediator. The Z-scheme system split water into H2 and O2 under visible light and simulated sunlight irradiation. The (CuGa)(1-x)Zn(2x)S2 possessed a p-type semiconductor character. The photoelectrochemical cell with a Ru-loaded (CuGa)0.5ZnS2 photocathode and a CoO(x)-modified BiVO4 photoanode split water even without applying an external bias. Thus, we successfully demonstrated that the metal sulfide material group can be available for Z-scheme and electrochemical systems to achieve solar water splitting into H2 and O2.

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The aim of this study was to analyze visual search strategies of baseball batters during the viewing period of the pitcher's motion. The 18 subjects were 9 experts and 9 novices. While subjects viewed a videotape which, from a right-handed batter's perspective, showed a pitcher throwing a series of 10 types of pitches, their eye movements were measured and analyzed. Novices moved their eyes faster than experts, and the distribution area of viewing points was also wider than that of the experts. The viewing duration of experts of the pitching arm was longer than those of novices during the last two pitching phases. These results indicate that experts set their visual pivot on the pitcher's elbow and used peripheral vision properties to evaluate the pitcher's motion and the ball trajectory.

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A two-step alkylation of single-walled carbon nanotubes was investigated. The functionalized SWNTs were characterized with vis-NIR and Raman spectrometers, scanning electron microscope, and thermogravimetric analysis. This one-pot alkylation of SWNTs with alkyllithium followed by alkyl halide is useful for the sidewall functionalization of SWNTs. This reaction shows significant substituent effects on the degree of functionalization of SWNTs. The degree of functionalization on SWNTs sidewall upon SWNTs may influence their characteristic properties on SWNTs sidewall by the substituent effects.