| Electrocortical activity in fetal sheep in the last seven days of gestation. | |
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MedLine Citation:
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PMID: 9782177 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. Electrocorticogram (ECoG) and myometrial electromyogram (EMG) were recorded continuously in chronically instrumented late gestation sheep fetuses (n = 9) to analyse: (1) 24 h ECoG patterns, (2) relationships between ECoG and myometrial contractility, and (3) 24 h ECoG patterns at the spontaneous onset of labour. 2. Spontaneous onset of labour was determined from the myometrial EMG. ECoG signals were purified by a denoising procedure of wavelet decomposition. High-voltage slow ECoG activity (HV) and low-voltage fast ECoG activity (LV) were determined mathematically, and HV-LV cycle periodicity was calculated by periodogram analysis. 3. Twenty-four hour rhythms were present in fetal ECoG HV-LV cycles in the 3-5 days prior to spontaneous onset of labour (P < 0.01). Cycle frequency was lower at 08.00-12.00 h and higher at 16.00-20.00 h (lights on at 07.00 h, lights off at 21.00 h). LV duration was longer at 20.00-24.00 h, and HV was shorter at 16.00-20.00 h. No relationship was found between ECoG cycles and myometrial contracture cycles. Twenty-four hour ECoG rhythms disappeared 1 day before the spontaneous onset of labour. 4. ECoG patterns changed 7 to 4 h prior to spontaneous onset of labour, percentage of time spent and duration of HV ECoG increased, and percentage of time spent in LV decreased significantly. ECoG HV-LV cyclicity was reduced 4-5 h prior to spontaneous onset of labour, indicating that the altered fetal hormonal and blood gas environment around the spontaneous onset of labour alter fetal neural function. |
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Authors:
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N Shinozuka; P W Nathanielsz |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: The Journal of physiology Volume: 513 ( Pt 1) ISSN: 0022-3751 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 1998 Nov |
Date Detail:
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Created Date: 1999-01-29 Completed Date: 1999-01-29 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 273-81 Citation Subset: IM |
Affiliation:
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Laboratory for Pregnancy and Newborn Research, Department of Physiology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853-6401, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Gas Analysis Blood Pressure / physiology Central Nervous System / embryology, physiology* Electroencephalography* Electromyography Electrophysiology Female Fetus / physiology* Heart Rate, Fetal / physiology Labor, Obstetric / physiology Myometrium / physiology Pregnancy Sheep |
| Comments/Corrections | |
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