Publications by authors named "Hiromi Okumura"

Semaphorin 3A (Sema3A), originally identified as a potent growth cone collapsing factor in developing sensory neurons, is now recognized as a key player in immune, cardiovascular, bone metabolism and neurological systems. Here we established an anti-Sema3A monoclonal antibody that neutralizes the effects of Sema3A both in vitro and in vivo. The anti-Sema3A neutralization chick IgM antibodies were screened by combining an autonomously diversifying library selection system and an in vitro growth cone collapse assay.

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The effects of phenothiazine and carbazole derivatives on the cell-cycle progression of human transformed culture cells were analyzed. After 2 days incubation, 5 microM 1-phenethylamino-3-phenothiazin-10-yl-propan-2-ol (1) induced strong mitotic arrest followed by cell death, and 20 microM 1-(3,6-dichloro-9H-carbazol-9-yl)-3-phenethylamino-2-propanol (5) and 1-(3,6-dibromo-9H-carbazol-9-yl)-3-phenethylamino-2-propanol (6) also induced cell death. The TUNEL-positive nuclei characteristic of apoptotic cell death were detected in cells treated with the compounds.

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The Dugesia japonica vasa-like gene B (DjVLGB) protein is a DEAD-box RNA helicase of a planarian, which is well known for its strong regenerative capacity. DjVLGB shares sequence similarity to the Drosophila germ-line-specific DEAD-box RNA helicase Vasa, and even higher similarity to its paralogue, mouse PL10. In this study, we solved the crystal structure of the DjVLGB N-terminal RecA-like domain.

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The present study was performed to generate monoclonal antibodies capable of detecting N-acetoxy-2-acetylaminofluorene (NA-AAF)-derived DNA adducts in human cells in situ. As an immunogen, we employed NA-AAF-modified single-stranded DNA coupled electrostatically to methylated protein and we produced five different monoclonal antibodies. All of them showed strong binding to NA-AAF-modified DNA, but had undetectable or minimal binding to undamaged DNA.

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The induction of vitellogenesis is a complex process requiring coordinated control and expression of many hepatic gene products, such as vitellogenin (VTG). To investigate the regulation of VTG synthesis, knowledge of the molecular genetics of VTG is required. Here, the authors have isolated a partial cDNA encoding Japanese eel VTG using an immunoscreening technique.

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