Journal of Radiation Research
Online ISSN : 1349-9157
Print ISSN : 0449-3060
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Volume 28, Issue 4
Displaying 1-5 of 5 articles from this issue
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  • Active Site and Conformation-Directed Photoinactivation of Copper-Dependent Oxidoreductases: Studies of Pig Kidney Diamine Oxidase and Agaricus bisporus Tyrosinase
    MANZOOR A. SHAH, ISRAR A. KHAN, RASHID AL
    1987 Volume 28 Issue 4 Pages 233-242
    Published: December 15, 1987
    Released on J-STAGE: June 16, 2006
    DOIhttps://doi.org/10.1269/jrr.28.233
    JOURNAL FREE ACCESS
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    Pig kidney diamine oxidase and Agaricus bisporus tyrosinase were observed to be irreversibly inactivated by 253.7 nm ultraviolet (UV) radiation. By means of hydrodynamic and UV spectral studies, the direct accessibility of the catalytic center of diamine oxidase to UV radiation has been shown to be a possible route for the photoinactivation of this oxidase. Fluorescence and thermal denaturation studies indicated that UV, radiation by perturbing the major molecular forces, destabilizes and unfolds the natural structure of tyrosinase, which in turn leads to the inactivation of this enzyme. A comparative analysis of the inactivation data of the two oxidases revealed that photoinactivation was a very complex, “conformation directed” phenomenon involving the disruption of intramolecular forces and the unfolding of the compact and globular conformation of the natural enzyme.
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  • Monochromatic X-ray Irradiation System (0.08-0.4 nm) for Radiation Biology Studies Using Synchrotron Radiation at the Photon Factory
    KATSUMI KOBAYASHI, KOTARO HIEDA, HIROSHI MAEZAWA, MASAMI ANDO, TAKASHI ...
    1987 Volume 28 Issue 4 Pages 243-253
    Published: December 15, 1987
    Released on J-STAGE: June 16, 2006
    DOIhttps://doi.org/10.1269/jrr.28.243
    JOURNAL FREE ACCESS
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    A monochromatic X-ray irradiation system in the 0.08-0.4 nm wavelength range is described. This uses for the first time, synchrotron radiation at the Photon Factory as an X-ray source (2.5 GeV electron storage ring). It consists of a beam shutter, a Si crystal monochromator, ionization chambers for monitoring exposures, a sample stage, and a control system. The beam is 2.7 × 30 mm at the sample position with a fairly uniform intensity of several kR/min (one C · kg-1 · min-1). The wavelength is an extremely pure Δλ/λ ?? 10-3. A 35 mm culture dish is moved across the vertical height (2.7 mm) of the X-ray beam using a sample scanning stage. This improves the uniformity of the radiation intensity on the sample. The sample can be irradiated under normal or controlled atmospheric conditions. Since 1984, a variety of biological materials have been irradiated, including cultured mammalian cells. Results of yeast cells are presented to illustrate the performance of this irradiation system.
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  • Role of the Main Cytosine Radiolytic Product in Ionizing Radiation-Induced Mutagenesis
    HITOSHI AYAKI, OSAMU YAMAMOTO, SHOZO SAWADA
    1987 Volume 28 Issue 4 Pages 254-261
    Published: December 15, 1987
    Released on J-STAGE: June 16, 2006
    DOIhttps://doi.org/10.1269/jrr.28.254
    JOURNAL FREE ACCESS
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    When 14C cytosine was incorporated in M13 mp10 phage, in the phage DNA both cytosine and thymine residues were labelled. The single stranded phage DNA was isolated and irradiated in a buffer solution using 60Co gamma-rays. After the addition of TCA, the DNA precipitated was filtered. The ratio of the radioactivity of the filtrate to the total increased with increasing radiation dose. The precipitate -was hydrolyzed with acid and the base modification was analyzed by TLC. The modification yield also increased with increasing dose. Chromatograms showed that the main product was urea. In the case of cytosine radiolysis, trans-5, 6-dihydroxy-5, 6-dihydrouracil was found to be the main product before acid treatment; whereas, urea was the main product after acid treatment. This fact suggests that the trans-5, 6-dihydroxy-5, 6-dihydrouracil retained in the irradiated DNA is responsible for the gamma-ray induced C-T transition.
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  • In vivo Effects of Hyperthermia on the Cellular Uptake of Adriamycin
    SAKAE NAGAOKA, SHOJI KAWASAKI, YUICHI KARINO, YOSHIO HIRAKI, TAKASHI N ...
    1987 Volume 28 Issue 4 Pages 262-267
    Published: December 15, 1987
    Released on J-STAGE: June 16, 2006
    DOIhttps://doi.org/10.1269/jrr.28.262
    JOURNAL FREE ACCESS
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    The cellular uptake of Adriamycin (ADR) by solid tumors consisting of Ehrlich ascites tumor cells (EATC) was investigated. The intracellular levels of ADR in the EATC were measured by flow cytometry. The EATC tumors were heated at various temperatures for 30 min after the in vivo administration of ADR to the mice into which the EATC were inoculared. The amount of intracellular ADR in the EATC excised from the mice treated with 40°C hyperthermia was increased by 80% over that determined for those treated at body temperature. However, the quantity of ADR in the EATC excised from mice which received 43°C hyperthermia was similar to that for those treated at body temperature. These results indicate that combined therapy using hyperthermia and ADR has both synergic and additive effects, depending on the temperatures used for hyperthermia.
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  • In Vitro Neoplastic Transformation by Neutron Beams —Relative Biological Effectiveness and Dose Fractionation—
    MIEKO YASUKAWA, TOYOZO TERASIMA, TAKESHI FURUSE, HIROSHI OHARA, HIROSH ...
    1987 Volume 28 Issue 4 Pages 268-273
    Published: December 15, 1987
    Released on J-STAGE: June 16, 2006
    DOIhttps://doi.org/10.1269/jrr.28.268
    JOURNAL FREE ACCESS
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