| Project/Area Number |
18390306
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Embryonic/Neonatal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
KIMURA Yoshitaka Tohoku University, Tohoku University Biomedical Engineering Research Organization, Professor (40261622)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Takuya Tohoku University Biomedical Engineering Research Organization, Assistant professor (70396539)
CHISAKA Hiroshi Tohoku University Hospital, 病院, Lecturer (40323026)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥13,820,000 (Direct Cost: ¥12,500,000、Indirect Cost: ¥1,320,000)
Fiscal Year 2007: ¥5,720,000 (Direct Cost: ¥4,400,000、Indirect Cost: ¥1,320,000)
Fiscal Year 2006: ¥8,100,000 (Direct Cost: ¥8,100,000)
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| Keywords | fetal electrocardiogram / fetal heart ischemia / 胎児モニタリング / 心筋虚血 / 胎仔脳出血 |
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| Research Abstract |
Methods: Experiments were performed with pregnant C57BL/6N mice and 17 dpc fetuses. The measurements were carried out in the Fluid Dynamics Laboratory of the Tohoku University to take advantage of their ultrasonogram experimental facilities for animals. Caesarean section was carried out in pregnant mice after anesthesia and electrodes were attached to the fetuses to measure fetal ultrasonogram. 5 minute clipping and 5 minute release of the branches of the uterine artery was performed three times in tandem and the results were monitored by ultrasonogram.
Results: The fetal heart potential was as low as a few microvolts (μV) and because of this low signal extraction of the fetal electrocardiogram proved to be very troublesome. To overcome this problem, we developed a needle electrode that contained a signal amplification mechanism and were able to reduce the noise to a minimal level. To our knowledge, we are the first group in the world to report the successful measurement of the fetal el
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ectrocardiogram. Moreover, based on these investigations, we were able to identify the characteristic "T-wave" from the fetal electrocardiogram that had been so far believed to be nonexistent in mice. Next, we investigated the alterations in the electrocardiogram pattern and fetal heart rate because of the periodic constraint and release (5 minutes each, 3 times repeated) of the branches of the uterine artery. The results showed increase of the T-wave during constraint by clipping of the branches of the artery, accompanied with frequent arrhythmia, which lead to a reduction of fetal heart rate. After release of the clipping, frequent arrhythmia was again observed and the heart rate gradually improved to a normal level. Furthermore, during these analyses we were able to extract an ultrasonogram from the fetal brain that showed the blood flow in the branches of the middle cerebral artery. However, due to the breathing of the mother, it was difficult to obtain a clear image from the ultrasonogram that showed the area of interest in the brain. Because of this hindrance, we were unable to produce a real-time image of the blood flow in the brain during constraint and release of the branches of the uterine artery.
Discussion: Our analysis shows that fetal electrocardiogram and ultrasonogram can be a useful tool to monitor fetal ischemia. Less
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