The Effect of Ginkgo Biloba Extract on Hypoxic Fraction of C3H Mouse Fibrosarcoma / 대한치료방사선과학회지

PURPOSE: To investigate the effect of Ginkgo biloba extract (GBE) on hypoxic cell fraction and metabolic status in fibrosarcoma (FSa II) of C3H mouse. MATERIALS AND METHODS: Fibrosarcoma (Fsa II), 6mm in diameter, growing in the right hindleg muscle of C3H mouse was used for estimation of hypoxic cell fraction using comparison of TCD50. Radiation was given one hour after administrationof GBE (100 mg/Kg, i.p.) with or without priming dose of GBE (100 mg/Kg, i.p.) given 24 hours earlier. Radiation was also given under air breathing condition or clamp hypoxia withour GBE as controls. 31P NMR spectroscopy was performed before and one hour after administration of GBE with or without priming dose of GBE. RESULTS: TCD50/120's were 81.7(77.7-86.0) Gy when irradiated under clamped hypoxia, 69.6 (66.8-72.5) Gy under air breathing condition,67.5(64.1-71.1) Gy with a single dose of GBE (100 mg/kg) given one hour before irradiation, and 62.2(59.1-65.5) Gy with two doses of GBE given at 25 hours and one hour before irradiation. The hypoxic cell fractions, estimated from TCD50/120's were 1.6% under air breathing ondition, 7.2% after single dose of GBE, and 2.7% after two doses of GBE. He results of 31P NMR spectroscopy were as follows. PCr/Pi ratio was 0.27 +/- 0.04 and 0.40 +/- before nd one hour after a single dose of GBE(p<0.01). These findings indicate that the metabolic status is slightly improved after a single dose and markedly after repeated administrations. CONCLUSION: GBE decreases the hypoxic cell fraction and improves the metabolic status of tumor, probably by increasing the blood flow and delivery of oxygen and nutrients, resulting in increased radiosensitivity of tumor.

Analysis of Chromosomal Aberration Induced by Low Dose of Radiation / 대한치료방사선과학회지

Chromosomal aberration analysis, as a basis for biological radiation dosimetry, was performed for radiation dose ranges below 150 cGy. The yield, ratio of lymphocytes with dicentric and/or ring chromosomes, was 0, 0, 0.4, 0.5, 0.6, 0.8, 1.8, 5.5, 8.0, and 18.5% for 0, 5, 10, 15, 20, 25, 50, 75, 100 and 150 cGy, respectively. The Qdr, ratio of dicentric and ring chromosomes in total lymphocytes, was 0, 0, 0.004, 0.005, 0.006, 0.009, 0.018, 0.055, 0.084 and 0.207, respectively. The Qdr, ratio of dicentric and ring chromosomes in lymphocytes with aberration, was 1.0 for the radiation doses up to 75 cGy and 1.05 and 1.11 for 100 and 150 cGy, respectively. From the results, it seems possible to estimate radiation dose from Ydr when the exposure is 25 cGy or more. All the 5 radiation workers studied, with exposure much less than 1 mSv per month, had chromosomal aberrations. And acentric fragment pairs, in addition to dicentric and ring chromosomes, showed good dose response relationship and so may be useful for biological dosimetry for low dose radiation exposure, accidental or occupational.