| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
A capacitive heating has been mainly performed by radio-frequency hyperthermia, by which broad and nonselective heating is only possible. On the other hand, it is possible to accomplish a selective heating by an inductive method using an adequate hyperthermic agent or materials. ln a previous study, we have developed the method that used dextran magnetite (DM) and thermosensitive magneto-liposome (TMs) as magnetic materials, and reported the characteristics and the result of treatment. Due to its nature of temperature sensitivity, TMs are potentially useful for drug (example ; anticancer agents etc) release in response to local hyperthermia. But the particle size of TMs was small and inadequate as an embolus. To solve these problems, DM albumin micro sphere (DM-AMs) was developed afresh. In this study, we investigated in vitro and in vivo heating properties of DM- AMs in an electromagnetic field. DM-AMs used in this study is 4 to 6 mum of in diameter, 39.6 % in iron content. The size a
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nd concentration can be changed easily. DM-AMs suspeusions at its various concentrations (as iron) were exposed to an electromagneric field by an inductive heating unit at a 500 kHz frequency with an output of 7 kW.The temperature of the solution was monitored by using a fluoroptic thermometer. There were temperature rises of approximately 6 ﾟC / 7 min and 6 ﾟC 1 3 min by inductive heating at the concentrations of 10 mg Fe/mI and 20 mg Fe/mI respectively. The caudal lobe of liver of rat was embolized via arterial with DM-Ams, and exposed to an induction field. There was a temperature rise up to 43ﾟC for 25 mm-inductive heating using DM-Ams of 10 mg Fe/mI in TMs.was performed of rat was warmed to 43 degrees with induction hyperthermia. The rectum temperature was slightly elevated due to indirect heating with DM-Ams, but the temperature difference between the tumor and rectum was obvious and significant. ln histological examination, DM-AMs was taken in sinus of the caudal lobe of liver and inside of implanted tumor. Tumor cells showed rough arrangement in peripheral part, and necrosis and fibrous change were recognized in the central part. DM-Ams had a nature to release incorporated drugs, then it is suggested that DM-AMs are usefull for hyperthrmo-chemo-embolization treatment. Only a tumor was warmed selectively, and possibility to can do selective hyperthermia was suggested by doing embolism. These results were reported in the 14th and 15th congress of Japanese hyperthermia society. Less
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