| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
INTRODUCTION
Electrochemotherapy is available to enhance the entry of anti-neoplastic agents into murine osteosarcoma cells in the bone lesion. In this experiment model, we investigated the efficacy and cause of electrochemotherapy whether it attributed to the electroconductivity of bone, the distance between electrode and the difference between configuration and number of electrode.
MATERIALS AND METHODS
To produce solid murine tumors in bone, resected human osteosarcoma was cut into fine pieces, and inserted into the bone marrow of the hind-limb of Nude rat converting from the SCID mouse.
After transplantation, the tumor diameter was checked by X-ray photogram and the experiment was started when it reached 5 mm. The electroporation was done by the electroporator (T820) of BTX.
The changes of tumor volume were compared sequentially among the two groups : Drug (D) + Electroporation (E) and neither D nor E.As an anti-neoplastic agent, we used bleomycin (BLM).
The electrical resistivity betwee
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n electrodes which held the tumor was measured, and heat (Calaory) which arises by electroporation was calculated.
The tumor tissue concentration of BLM was analyzed based on the bio-assay and compared among the two groups : D+E and D without E.Histology was investigated on the tumor necrosis.
RESULTS AND DISCUSSIONS
There was the reduction of the tumor diameter in the electroporation (E) group. The reduction of the tumor diameter has been obtained in the group in which the distance between electrodes spread 10mm, 15mm, 20mm and interval. Effective examples were the 23 limbs in 38 limbs.
The effective example increased in multiple dose group under operation, when it was compared at the frequency in which 1 time operation, 2 time operation, 3 time operation did (D+E+).
The concentration in the tumor tissue of BLM showed the high value, since it has it, in comparing without electroporation group (D+E-) in anti-cancer drug and electroporation group (D+E+), and it seemed to be the effect of electroporation that BLM was incorporated in the interosseous tumor tissue. The production heat calculated from electrical resistivity between tumors did not bring about the effect in anti-tumor effect. In-the example of showing the progress that the bone destruction was restored in X-ray photogram, there were necrosis and elimination of the tumor cell in the pathohistological retrieval. It seemed to be the opinion which proved that electrochemotherapy for the interosseous lesion through the bone has the cytotoxicity reaction.
The significance could not be accepted between distance and effect between electrodes. Less
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