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- Franklin, GC, et al.
(författare)
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Genomic imprinting and mammalian development
- 1996
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Ingår i: PLACENTA. - 0143-4004. ; 17:1, s. 3-14
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Forskningsöversikt (populärvet., debatt m.m.)abstract
- Genomic imprinting, which results in the mono-allelic expression of certain genes in a parent of origin-dependent manner, represents a specialized form of gene regulation which may be vitally important for mammalian development. The mechanisms which underlie imprinting and the molecular nature of the imprint itself remain elusive but most likely include epigenetic modifications of DNA, such as methylation and chromatin structure changes. It is clear, however, that many of the known imprinted genes play important developmental roles and that changes in the functional imprinting of some of these genes may have important pathological consequences, including placental abnormalities.
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- Liu, Y X, et al.
(författare)
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Localization and distribution of tissue type and urokinase type plasminogen activators and their inhibitors Type 1 and 2 in human and rhesus monkey fetal membranes
- 1998
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Ingår i: Placenta. - : Saunders Elsevier. - 0143-4004 .- 1532-3102. ; 19:2-3, s. 171-180
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Tidskriftsartikel (refereegranskat)abstract
- Fetal membranes consist of 10 distinct layers including components of amnion, chorion and decidua, the latter being of maternal origin. They form mechanically integrated sheets capable of retaining amniotic fluid and play an essential role in protecting fetal growth and development in the pregnant uterus. The extracellular matrix, substrate for plasminogen activators (PAs), is an important supportive framework of the fetal membranes. Fetal membranes from women with preterm premature rupture of membranes may differ in their protease activity compared with normal membranes. To identify the presence of PAs and their inhibitors (PAI) and their possible role in the process of fetal membrane rupture, this study investigated the distribution and localization of both protein and mRNA for tissue (t) and urokinase (u) PA and their inhibitors type 1 (PAI-1) and type 2 (PAI-2) in amniochorion of human and rhesus monkey using conventional and confocal immunofluorescence microscopy. In situ hybridization analysis showed that the distribution and localization of mRNAs for tPA, uPA, PAI-1 and PAI-2 were similar in the fetal membranes of human and rhesus monkey; no obvious species difference was observed. Evidence of tPA mRNA was detected in amniotic epithelium, trophoblast cells and nearly all cells of the decidual layer. Strong expression of uPA mRNA was noted in the decidual cells which increased in intensity as the abscission point was approached. Weak staining in chorion laeve trophoblast was also detected. In situ hybridization experiments showed PAI-1 mRNA to be concentrated mainly in the decidual cells, some of which were interposed into the maternal-facing edge of the chorion laeve. Maximal labelling of the decidua occurred towards the zone of abscission. Weak expression of PAI-1 mRNA was also noted in some cells of the chorion laeve. The distribution of PAI-2 mRNA in amniochorion was also concentrated in the cells of the decidual layer, maximum expression of the mRNA was in the level of abscission. No detectable amount of mRNAs for tPA, uPA, PAI-1 and PAI-2 was found in the fibroblast, reticular and spongy layers. Distribution of the proteins of tPA, uPA and PAI-1 in the fetal membranes of these two species was consistent with the distribution of their mRNA. Anti-PAI-2 immunofluorescence was found to be strongly concentrated in the amniotic epithelium, but PAI-2 mRNA was negative in this layer, suggesting that the epithelium-associated PAI-2 is not of epithelial origin. These findings suggest that a local fibrinolysis in fetal membranes generated by precisely balanced expression of PAs and their inhibitors via paracrine or autocrine mechanisms may play an essential role in fetal membrane development, maturation and in membrane rupture. Following an analysis of the distribution and synthesis of activators and inhibitors it was found that they may play a role in abscission during the third stage of labour.
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- Al-Khan, A., et al.
(författare)
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IFPA Meeting 2010 Workshops Report II: Placental pathology; Trophoblast invasion; Fetal sex; Parasites and the placenta; Decidua and embryonic or fetal loss; Trophoblast differentiation and syncytialisation
- 2011
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Ingår i: Placenta. - : Elsevier BV. - 1532-3102 .- 0143-4004. ; 32:Suppl. 2, s. 90-99
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 diverse topics were discussed in twelve themed workshops, six of which are summarized in this report. 1. The placental pathology workshop focused on clinical correlates of placenta accreta/percreta. 2. Mechanisms of regulation of trophoblast invasion and spiral artery remodeling were discussed in the trophoblast invasion workshop. 3. The fetal sex and intrauterine stress workshop explored recent work on placental sex differences and discussed them in the context of whether boys live dangerously in the womb.4. The workshop on parasites addressed inflammatory responses as a sign of interaction between placental tissue and parasites. 5. The decidua and embryonic/fetal loss workshop focused on key regulatory mediators in the decidua, embryo and fetus and how alterations in expression may contribute to different diseases and adverse conditions of pregnancy. 6. The trophoblast differentiation and syncytialisation workshop addressed the regulation of villous cytotrophoblast differentiation and how variations may lead to placental dysfunction and pregnancy complications. (C) 2011 Published by IFPA and Elsevier Ltd.
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