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<pubmed limit=10>Placental+Membrane</pubmed>
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===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==
==2015==

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Cite this page: Hill, M.A. (2024, May 22) Embryology Placenta - Membranes. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Placenta_-_Membranes

10 Most Recent Papers

Note - This sub-heading shows an automated computer PubMed search using the listed sub-heading term. References appear in this list based upon the date of the actual page viewing. Therefore the list of references do not reflect any editorial selection of material based on content or relevance. In comparison, references listed on the content page and discussion page (under the publication year sub-headings) do include editorial selection based upon relevance and availability. (More? Pubmed Most Recent)


Placental Membrane

<pubmed limit=10>Placental+Membrane</pubmed>


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