Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 78 , Issue 9
Showing 1-4 articles out of 4 articles from the selected issue
  • Hirota FUJIKI, Masami SUGANUMA
    2002 Volume 78 Issue 9 Pages 263-270
    Published: 2002
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    We found that (-)-epigallocatechin gallate (EGCG), the main constituent of green tea and green tea extract, the lyophilized form of green tea infusion, inhibited both activation of protein kinase C and tumor promotion on mouse skin: The results led us to suggest green tea as a cancer preventive for humans. Inhibition of chemical carcinogenesis in rodents, inhibition of cell growth and induction of apoptosis on human cancer cell lines, organ distribution of 3H-EGCG in mice, multifunctional actions, and the synergistic cancer preventive activity of green tea with sulindac were studied. All our results show that green tea is a promising beverage for the purpose of cancer prevention in humans.
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  • Haruo TANAKA
    2002 Volume 78 Issue 9 Pages 271-276
    Published: 2002
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Anomalous changes in the geoelectric potential difference between electrodes on Niijima Island first appeared at the end of April 2000 about two months before the onset of a major volcanic and seismic activity in the Izu island region. They ceased at the end of August 2000 simultaneously with the decline of the volcanic and seismic activity. The temporal change in the magnitude of 0.01Hz Fourier coefficient of the geoelectric potential difference was analyzed on the basis of a critical“time-to-failure”model. It was found that the temporal change was well explained by a power-law decorated with a log-periodic oscillation. This indicates that the possible generation mechanism of the electric potential changes was related to a critical phenomenon. Several possible mechanisms that may cause this phenomenon are suggested.
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  • Hideyuki NAKANO, Akira KOUCHI, Masahiko ARAKAWA, Yuki KIMURA, Chihiro ...
    2002 Volume 78 Issue 9 Pages 277-281
    Published: 2002
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Based on experiments that model interstellar organic materials, we found that both C and N contents and IR spectra of insoluble organic materials in carbonaceous chondrites could be reproduced well by the aqueous alteration and the subsequent thermal metamorphism. The resulting sample shows strong evidence of diamond, which indicates that this process is an unexpeccted mechanism that might produce extensive amount of diamond in meteorites' parent bodies. Because this process requires neither high pressures nor energetic processes, the present results suggest an alternate origin of diamonds in meteorites.
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  • Miyoko IKEJIMA, Tadashige NOZAKI, Shoichiro KURATA, Shunji NATORI, Hir ...
    2002 Volume 78 Issue 9 Pages 282-285
    Published: 2002
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Poly(ADP-ribose) polymerase (PARP) was purified from embryonic NIH-Sape-4 cells of Sarcophaga peregrina almost to homogeneity. The purification was carried out using phosphocellulose and 3-aminobenzamide-Sepharose column chromatographies. The purified enzyme had an apparent molecular weight of 113kDa on SDS-polyacrylamide gel electrophoresis. The addition of DNA was essential for the activity of the purified enzyme, and the reaction was stimulated by the presence of histone and magnesium ion. The Km for NAD was 43μM and the optimum temperature for the PARP activity ranged from 20-25°C. MALDI (matrix-associated laser desorption ionisation)-TOF (time-of-flight) mass spectrometric analysis gave a signal at 112, 402. This value was close to 113, 033, the predicted mass from its cDNA sequence. This suggests that full length PARP is present as a major native form without extensive post-translational modification.
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