| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1999: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
We tried to measure a reactive electricmagnetic field of a leg in rabbit after pulsing electromagnetic stimulation (10, 20, 30 Gaus, 2Hz) using Superconduction Quantum Interference Device. However, we had a lot of noise composed of the pulsing electromagnetic field, reactive magnetic field from soft tissues (nerve, muscle etc.), Therefore, we can not detect the reactive magnetic field from bone tissue. Next we try to evaluate the impedance of bone tissue in the process of callus formation. We used lengthend callus of tibiae in 30 rabbits. Thirty Japanese white rabbits were divided into 3 groups : Group ES (early stimulation ; Alternating stimulation from just after operation), Group LS (late stimulation ; electrical stimulation from 3 weeks after operation) Group C (control). The waiting period was 1 week and the lengthening rate was 0.5mm twice daily. Radiological, histological, and electrophysiological studies were done on animals sacrificed at 2 weeks after the completion of lengthening. Radiologically in groups ES and LS, corticalization and medullarization began earlier than in group C.The values of bone mineral density of the lengthened callus in groups ES and LS were significantly decreased as compared with those in group C.The impedance values for the resected tibia in group ES were significantly increased, as compared to those in group C.The impedance values of resected tibia increased with the maturation of the lengthened callus. When electrical current route was composed of bone and soft tissue as a simple parallel circuit, we considered that about 64% of the whole electrical current passed through bone tissue. Alternating current electrical stimulation to the lengthened callus was useful for remodeling of the mineralized callus, and the impedance of lengthened callus reflected the maturation itself.
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