| Project/Area Number |
09557092
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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 | 展開研究 |
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| Research Field |
Embryonic/Neonatal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
OKAMURA Kunihiro Tohoku University School of Medicine, Department of Obstetrics and Gynecology, associate professor, 医学部, 助教授 (90124560)
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| Co-Investigator(Kenkyū-buntansha) |
OHWADA Kazunori Atom Medical Co LTD, 浦和工場・技術部課長, 研究職
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | Time-frequency analysis / wavelet transform / fetal heart beat fluctuation / fetal acidemia / gamma distribution |
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| Research Abstract |
We examined whether the non-linear control mechanism of the fetal autonomic nervous system would change in various fetal states. 8000 or more fetal heart beats were detected from normal, hypoxemic and acidemic fetuses. Fetal heart Doppler signal intervals were determined in a high-precision autocorrelation method and a time series of fetal heart rate fluctuation was obtained. The distribution of the amplitude of temporal fluctuation in the low frequency component of fetal heart rate frequency was studied using a method of time-frequency analysis called wavelet transform. Spline 4 was used as the mother wavelet function. A gamma distribution was observed from 17 weeks of gestation onward. The value of the parameter upsilon of this gamma distribution was approximately 1.6 and remained constant regardless of the gestation age or the time of the day. The value of upsilon decreased significantly to 0.77 when the fetus developed acidemia, and was 1.51 in hypoxemia and 1.54 in a normal condition.
This study elucidates a non-linear structure of the time series of heart rate fluctuation of the gamma distribution in human fetus. This technique may provide a new quantitative index of fetal monitoring to diagnose fetal acidemia.
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