These studies explore the distribution of blood flow among small samples of placental tissue. Labeled microspheres (14 ± 1 pm) were Injected Into the left ventricle of six un-anesthetized ewes and Into the jugular vein of the fetus In utero. A total of 3,576 samples weighing 31. +11. (S.D.) mg were taken from seventeen cotyledons and counted for flow labels. Maternal and fetal flow within the cotyledons were both normally distributed with standard deviations of 44%. The maternal/ fetal flow ratio was less than 0.5 In 9% of the cotyledon, between 0.5 and 1.5 In 70%, and greater than 1.5 In 21%. Errors due to the method were estimated to contribute less than 10% of the flow variances. Maternal and fetal flows were significantly correlated (r = 0.57, p < .001). Spatial flow patterns were visualized using computerized Image processing. The distribution of maternal and fetal flow may be a sensitive determinant of water transfer, and the distribution of their ratio explains about 50% of the uterine—umbilical venous oxygen tension gradient. Analysis of the correlation between samples vs. the distance separating them suggested a weight of roughly 125 mg for hypothetical placental regulatory units.
","abstract_html":"<p>These studies explore the distribution of blood flow among small samples of placental tissue. Labeled microspheres (14 ± 1 pm) were Injected Into the left ventricle of six un-anesthetized ewes and Into the jugular vein of the fetus In utero. A total of 3,576 samples weighing 31. +11. (S.D.) mg were taken from seventeen cotyledons and counted for flow labels. Maternal and fetal flow within the cotyledons were both normally distributed with standard deviations of 44%. The maternal/ fetal flow ratio was less than 0.5 In 9% of the cotyledon, between 0.5 and 1.5 In 70%, and greater than 1.5 In 21%. Errors due to the method were estimated to contribute less than 10% of the flow variances. Maternal and fetal flows were significantly correlated (r = 0.57, p < .001). Spatial flow patterns were visualized using computerized Image processing. The distribution of maternal and fetal flow may be a sensitive determinant of water transfer, and the distribution of their ratio explains about 50% of the uterine—umbilical venous oxygen tension gradient. Analysis of the correlation between samples vs. the distance separating them suggested a weight of roughly 125 mg for hypothetical placental regulatory units.</p>","abstract_has_math":false,"creators":["Power, Gordon G.","Dale, P. Steven","Nelson, Paul S."],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Thesis","degree_discipline":"Bioinformatics & Computational Biology","degree_department":null,"school":null,"contributors":["Ivan R. Neilsen","Gordon G. Power","C. Duane Zimmerman","S. Andrew Yakush","Paul Y. Yahiku"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1980,"date_issued":"1980-08-01T07:00:00Z","date_published":"1980-08-01T07:00:00Z","updated_at":"2026-07-24T02:54:17Z","subjects":["Medical Biomathematics and Biometrics","Maternal-Fetal Exchange; Fetal Blood; Placenta"],"languages":["English"],"rights":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsrepository.llu.edu/etd/1194","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Ivan R. Neilsen","Gordon G. Power","C. Duane Zimmerman","S. Andrew Yakush","Paul Y. 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The author retains all other copyrights."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsrepository.llu.edu/etd/1194"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["These studies explore the distribution of blood flow among small samples of placental tissue. Labeled microspheres (14 ± 1 pm) were Injected Into the left ventricle of six un-anesthetized ewes and Into the jugular vein of the fetus In utero. A total of 3,576 samples weighing 31. +11. (S.D.) mg were taken from seventeen cotyledons and counted for flow labels. Maternal and fetal flow within the cotyledons were both normally distributed with standard deviations of 44%. The maternal/ fetal flow ratio was less than 0.5 In 9% of the cotyledon, between 0.5 and 1.5 In 70%, and greater than 1.5 In 21%. Errors due to the method were estimated to contribute less than 10% of the flow variances. Maternal and fetal flows were significantly correlated (r = 0.57, p < .001). Spatial flow patterns were visualized using computerized Image processing. The distribution of maternal and fetal flow may be a sensitive determinant of water transfer, and the distribution of their ratio explains about 50% of the uterine—umbilical venous oxygen tension gradient. Analysis of the correlation between samples vs. the distance separating them suggested a weight of roughly 125 mg for hypothetical placental regulatory units.
"]},{"key":"dc:title","label":"Title","values":["Distribution of Maternal and Fetal Blood Flow within Cotyledons of the Sheep Placenta"]}]}],"canonical_facts":{"dc:contributor":["Ivan R. Neilsen","Gordon G. Power","C. Duane Zimmerman","S. Andrew Yakush","Paul Y. Yahiku"],"dc:creator":["Power, Gordon G.","Dale, P. Steven","Nelson, Paul S."],"dc:description.abstract":["These studies explore the distribution of blood flow among small samples of placental tissue. Labeled microspheres (14 ± 1 pm) were Injected Into the left ventricle of six un-anesthetized ewes and Into the jugular vein of the fetus In utero. A total of 3,576 samples weighing 31. +11. (S.D.) mg were taken from seventeen cotyledons and counted for flow labels. Maternal and fetal flow within the cotyledons were both normally distributed with standard deviations of 44%. The maternal/ fetal flow ratio was less than 0.5 In 9% of the cotyledon, between 0.5 and 1.5 In 70%, and greater than 1.5 In 21%. Errors due to the method were estimated to contribute less than 10% of the flow variances. Maternal and fetal flows were significantly correlated (r = 0.57, p < .001). Spatial flow patterns were visualized using computerized Image processing. The distribution of maternal and fetal flow may be a sensitive determinant of water transfer, and the distribution of their ratio explains about 50% of the uterine—umbilical venous oxygen tension gradient. Analysis of the correlation between samples vs. the distance separating them suggested a weight of roughly 125 mg for hypothetical placental regulatory units.
"],"dc:identifier":["https://scholarsrepository.llu.edu/etd/1194"],"dc:language":["English"],"dc:rights":["This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights."],"dc:subject":["Medical Biomathematics and Biometrics","Maternal-Fetal Exchange; Fetal Blood; Placenta"],"dc:title":["Distribution of Maternal and Fetal Blood Flow within Cotyledons of the Sheep Placenta"],"thesis:degree_discipline":["Bioinformatics & Computational Biology"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T02:54:17Z"}