| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1990: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1989: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1988: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
Prostaglandins (PGs), of which precursor is polyunsaturated fatty acids of the membrane phospholipid, are known to affect the radiosensitivity of cells. In this work, PGA_1, PGA_2, PGE_1, PGE_2, and PGD_2 were examined for modification of the potentially lethal damage (PLD) repair and lethality of normal human fibroblast (NHF) cells irradiated with ^<137>Csgamma -rays. PGE_1 (50mug/ml) increased the surviving fraction of confluent NHF cells irradiated at 5Gy, followed by incubation at 37ﾟC for 0 or , hr before replating. However, a ratio of PLD repair at 5 Gy was not changed (11.0 -> 10.4). PGE_2 (50mug/ml) did not affect significantly the radiosensitivity of NHF cells or the ratio of PLD repair (11.0 -> 12.0). PGA_1, PGA_2 (10 and 50mug/ml) also inhibited PLD repair, although these were cytotoxic. On the contrary, PGD_2 (50mug/ml) depressed PLD repair (11.0 -> 5.4), although it did not affect the surviving fraction of cells when plated immediately after irradiation.
C3H mouse fibrosarcoma (OFSa) was irradiated with neutrons in the presence and absence of indomethacin, an inhibitor of prostaglandin biosynthesis, and/or FTS. Although combination of high LET radiation with drugs is known to be less effective than that of low LET radiation, combination of neutrons with indomethacin and FTS gave rise to a dose modifying factor of 1.5. This would be useful for decreasing the neutron dose in therapy.
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