Talk:Placenta - Membranes
| About Discussion Pages |
|---|
Glossary Links
Cite this page: Hill, M.A. (2024, April 25) Embryology Placenta - Membranes. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Placenta_-_Membranes |
2017
Function and failure of the fetal membrane: Modelling the mechanics of the chorion and amnion
PLoS One. 2017 Mar 28;12(3):e0171588. doi: 10.1371/journal.pone.0171588. eCollection 2017.
Verbruggen SW1, Oyen ML2, Phillips AT3, Nowlan NC1.
Abstract
The fetal membrane surrounds the fetus during pregnancy and is a thin tissue composed of two layers, the chorion and the amnion. While rupture of this membrane normally occurs at term, preterm rupture can result in increased risk of fetal mortality and morbidity, as well as danger of infection in the mother. Although structural changes have been observed in the membrane in such cases, the mechanical behaviour of the human fetal membrane in vivo remains poorly understood and is challenging to investigate experimentally. Therefore, the objective of this study was to develop simplified finite element models to investigate the mechanical behaviour and rupture of the fetal membrane, particularly its constituent layers, under various physiological conditions. It was found that modelling the chorion and amnion as a single layer predicts remarkably different behaviour compared with a more anatomically-accurate bilayer, significantly underestimating stress in the amnion and under-predicting the risk of membrane rupture. Additionally, reductions in chorion-amnion interface lubrication and chorion thickness (reported in cases of preterm rupture) both resulted in increased membrane stress. Interestingly, the inclusion of a weak zone in the fetal membrane that has been observed to develop overlying the cervix would likely cause it to fail at term, during labour. Finally, these findings support the theory that the amnion is the dominant structural component of the fetal membrane and is required to maintain its integrity. The results provide a novel insight into the mechanical effect of structural changes in the chorion and amnion, in cases of both normal and preterm rupture. PMID: 28350838 PMCID: PMC5370055 DOI: 10.1371/journal.pone.0171588
A correlative study of the allantois in pig and rabbit highlighting the diversity of extraembryonic tissues in four mammalian species, including mouse and man
J Morphol. 2017 Feb 6. doi: 10.1002/jmor.20657.
Hassan W1, Viebahn C1.
Author information
Abstract
Despite its conserved role in placenta and umbilical cord formation, the mammalian allantois shows remarkable diversity in size and form as well as in the timing of its appearance and attachment to the chorion. In the mouse, the common allantoic diverticulum is lacking; instead, the allantoic core domain is defined as a progenitor center for allantoic development. In this study, the allantoises of the pig and the rabbit as two nonrodent mammals of increasing significance in biomedical research are compared (1) morphologically using high resolution light and electron microscopy and (2) molecularly using brachyury mRNA expression as a mesodermal marker. Multiple small allantoic diverticula in the rabbit contrast with a single large cavity filling the entire allantois of the pig, but neither pig nor rabbit allantois expresses brachyury. The mesothelium on the allantois surface shows regional variability of cell contacts and microvilli, while blood vessels appear randomly around the allantoic diverticula in a mesodermal layer of variable thickness. Primordial germ cell-like cells are found in the allantois of the pig but not of the rabbit. To understand further the relevance of this developmental and morphological diversity, we compare the allantois development of pig and rabbit with early developmental landmarks of mouse and man. Our findings suggest that (1) tissue interaction between endoderm and mesoderm is important for allantoic development and vascular differentiation in species with a rudimentary allantoic diverticulum, (2) allantoic mesothelium plays a specific role in chorioallantoic attachment, allantoic differentiation and vascularization, and (3) there is a pronounced diversity in the extraembryonic migratory pathways of primordial germ cells among mammals. Finally, the phylogenetically basal characteristics of the pig allantois are suggestive of a functional similarity in mammals with a large allantois before placentation and in (aplacental) sauropsids with a chorioallantoic membrane well-adjusted to material exchange function. © 2017 Wiley Periodicals, Inc. KEYWORDS: allantoic core domain; brachyury expression; mesothelium; primordial germ cells; ultrastructure
PMID 28165148 DOI: 10.1002/jmor.20657
2015
The embryo reunited with its membranes in Göttingen
Development. 2015 Aug 15;142(16):2727-9. doi: 10.1242/dev.124719. Stern C.
Abstract
An EMBO workshop entitled 'Embryonic-Extraembryonic Interfaces' took place in Göttingen, Germany, in May 2015. It showcased the enormous breadth of this area not only by touching on the molecular and cellular mechanisms of development, but also because of its coverage of particularly interesting evolutionary questions and of several medically related aspects. This Meeting Review discusses some highlights from the workshop and the emerging themes in the field. © 2015. Published by The Company of Biologists Ltd. KEYWORDS: Extraembryonic tissues; Placenta; Visceral endoderm PMID 26286940
2013
Complete chorion-amnion separation presenting as a stuck fetus
Acta Obstet Gynecol Scand. 2013 May 6. doi: 10.1111/aogs.12161.
Kasuga Y, Miyakoshi K, Ikenoue S, Kadohira I, Matsumoto T, Minegishi K, Yoshimura Y. Source Department of Obstetrics and Gynecology, Keio University, School of Medicine, Tokyo, Japan.
Abstract
During feto-placental development, chorion-amnion fusion occurs in early second trimester and persistent separation of the membranes beyond 17 weeks' gestation is considered abnormal (1). Several reports have shown that complete chorion-amnion separation, defined as the amnion being separated from the chorion on at least three sides of the gestational sac, is associated with prenatal invasive procedures including amniocentesis (2-4). We would like to call attention to a case of complete chorion-amnion separation that occurred without any invasive procedures. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
PMID 23647025
2011
Magnesium concentration in amniotic fluid in the early weeks of the second trimester of pregnancy
BMC Res Notes. 2011 Jun 14;4:185.
Bocos Terraz JP, Izquierdo Álvarez S, Bancalero Flores JL, González López A, Escanero Marcén JF. Source Servicio de Bioquímica Clínica, Hospital Universitario Miguel Servet, Padre Arrupe-Edificio de Consultas Externas (3ª planta), 50009 Zaragoza, Spain. sizquierdo@salud.aragon.es.
Abstract ABSTRACT: BACKGROUND: We analyse magnesium levels in amniotic fluid to establish normal values for the 14th to 18th week of pregnancy and establish critical values that could be useful diagnostic and therapeutic guidelines for possible complications. FINDINGS: Ninety-two samples of amniotic fluid obtained by amniocentesis as well as the corresponding serum samples of pregnant women were analysed. The gestational age (mean ± SD) at which the amniotic fluid sample was obtained was 16.13 ± 1.87 weeks. Magnesium levels were determined by colorimetric assay with chlorophosphonazo-III using the the Cobas c 501 analyser (Roche Diagnostics). Statistical treatment of data was performed using the SPSS program, version 15.0.Results revealed a mean magnesium value of 1.65 ± 0.16 mg/dL in amniotic fluid and 1.97 ± 0.23 mg/dL in serum. CONCLUSIONS: It would be interesting to extend the study to a larger number of pregnant women to determine variations in normal magnesium values in the three trimesters of pregnancy.
PMID 21672230
