title: Micelles of pulmonary surfactant in human amniotic fluid at term.
abstract: Studies using in vitro analysis have shown that the interaction between pulmonary surfactant and vernix caseosa could explain the appearance of amniotic fluid turbidity. That phenomenon is interpreted based on the "roll-up" hypothesis. We tested the roll-up hypothesis by examining the presence of micelles of pulmonary surfactant in human amniotic fluid at term. Amniotic fluid samples were collected from each of six healthy pregnant women at term and at 16 wk of gestation. These samples were stained negatively and analyzed using an electron microscope. Ultrastructures present in amniotic fluid were compared with the structure of micelles derived from suspended surfactant TA isolated from bovine lung. Surfactant TA formed spheroidal and rod-shaped micelles 10-70 nm in diameter above the critical micelle concentration. Identical micelle particles were described in human amniotic fluid at term. In addition, surfactant protein B was identified in the micelle fraction of amniotic fluid. However, no micelles were found in human amniotic fluid taken at 16 wk of gestation. Our results support the view that pulmonary surfactant could induce the detachment of vernix caseosa and increase the turbidity of the amniotic fluid.
authors.affiliation: Department of Obstetrics and Gynecology, University of Fukui, Japan. kojigyne@fmsrsa.fukui-med.ac.jp
authors.forename: Koji
authors.initials: K
authors.lastname: Nishijima
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Shukunami
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tsukahara
authors.forename: Makoto
authors.initials: M
authors.lastname: Orisaka
authors.forename: Jun'Ichiro
authors.initials: J
authors.lastname: Miura
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Kotsuji
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002417:Cattle; D005260:Female; D006801:Humans; D008823:Micelles; D008854:Microscopy, Electron; D011247:Pregnancy; D011263:Pregnancy Trimester, Third / Q000378:metabolism; D037701:Pulmonary Surfactant-Associated Protein B / Q000032:analysis; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000378:metabolism; D014708:Vernix Caseosa / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008823:Micelles; D037701:Pulmonary Surfactant-Associated Protein B; D011663:Pulmonary Surfactants