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Placental pregnancy-associated plasma protein-A (PAPP-A) mRNA expression, placental PAPP-A protein concentration and maternal serum levels of PAPP-A were examined in pregnancies affected by trisomy 21 (n=8), trisomy 18 (n=7) and 15 normal controls at 12–15 weeks of gestation. The maternal serum concentration of PAPP-A in the trisomic group of pregnancies was significantly lower than in the normal...
The marked discrepancy between fetal and placental growth in the second half of pregnancy is reflected by a shift in balance of supply and demand from a state of oversupply in early pregnancy to a situation of relative shortage in late pregnancy. To some extent this shift is compensated by extensive morphological remodelling and functional adaptation of the placenta. The major features of placental...
The aim was to determine whether the fetal vasculature of the human placenta adapts in a uniform manner to different forms of hypoxic stress. Stereological analyses were performed on the intermediate and terminal villi of placentae obtained from each of the following conditions; high altitude (up to 2800 m), maternal iron-deficiency anaemia and pre-eclampsia. These conditions were taken to represent...
Homogenized first trimester human placenta exhibits both Ca 2+ -dependent (90–95 per cent) and Ca 2+ -independent (5–10 per cent) nitric oxide (NO)-synthesizing activities. Addition of tetrahydrobiopterin (BH 4 ) to homogenates containing Ca 2+ in maximally activating concentrations (>0.5 μm) results in a further 2–2.5-fold activation of NO synthesis, with half-maximal...
The abnormal umbilical artery Doppler waveform represented by absent end-diastolic flow velocity (AEDFV) identifies a group of preterm small-for-gestational age fetuses that are at high risk of perinatal death due to chronic fetal hypoxia. The placental ischaemia that results from inadequate trophoblast invasion of spiral arterioles leads to an assumption of placental villous hypoxia, though an alternative...
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...
Heterodimers of transporter for antigen processing proteins, Tap-1 and Tap-2, are essential components of the pathway that leads to expression of conventional HLA-A, -B class I transplantation antigens on cell surfaces. In this study, expression of the Tap-1 gene in trophoblast cells, some of which display novel and unconventional HLA class I molecules that include HLA-G and an HLA-C-like antigen,...
Trophoblas binucleate cells (BNC) in the ruminant placenta demonstrate a characteristic development, mature structure and migratory capacity whether situated in cytoledonary or intercotyledonary rerions of the placenta. However, previous immunocytochemical studies demonstrated clear differences in gene expression in granule contents of BNC according to their anatomical location with some proteins...
An improved method for long-term perfusion of the isolated human term placental lobule has been developed to investigate the maternofetal transfer of infectious agents, in particular the human immunodeficiency virus (HIV). The purpose of this paper is to describe those modifications that allow for substantiallyprolonged perfusions in a biohazard environment. The method described has been adapted from...
Many previous studies in both mouse and human placenta have implicated a role for colony stimulating factor-1 (CSF-1) in the regulation of placental development. In this study we have examined CSF-1 production by an immortalized cell line (TCL-1) derived from the choriodecidua, transfected with a retrovirus gene coding for the large-T antigen. TCL-1 cells were uniformly positive by immunocytochemistry...
The aim of this study was to examine whether differences in placental angiotensinase A (glutamyl aminopeptidase, EC 3.4.11.7) activities occurred in hypertensive complications of pregnancy compared with uncomplicated pregnancies. Biochemical and semiquantitative histochemical methods were used and compared for their applicability.Angiotensinase A activity was detected using l-αglutamyl-4-methoxy-2-naphthylamide...
Keratinocyte growth factor (KGF) is synthesized and secreted exclusively by mesenchymal cells, and acts through its receptor (KGFR) to stimulate epithelial proliferation. In vivo, KGF and KGFR comprise a mesenchymal-epithelial cell paracrine system that can mediate epithelial cell mitosis. In preliminary work, we noted that KGF was expressed in the rhesus monkey placenta, and we now report on the...
The uptakes of the tritiated, hydrolysis-resistant cationic (d-Phe-l-Lys), neutral (d-Phe-l-Ala) and anionic (d-Phe-l-Glu) peptides into human full-term placental brush-border membrane vesicles (BBMV) were time-dependent and into an osmotically-active space. Uptakes of d-Phe-l-Lys and d-Phe-l-Glu were temperature-dependent. Uptake of d-Phe-l-Lys was electroneutral (either cation, exchange or anion...
The present study was undertaken in order to characterize and determine angiotensin (Ang) II receptors and renin in the porcine placenta and fetal membranes. High densities of Ang II receptors of subtype 2 (AT 2 receptors) were demonstrated in all parts of the placenta and fetal membranes throughout gestation. AT 1 receptors (subtype 1) were only found in the first part of the gestation...
To understand the role of vascular endothelial growth factor (VEGF) in placental development, we examined immunohistochemically 56 placentae ranging from 6–41-weeks gestation using rabbit antibody to a synthetic multiple antigen peptide (MAP), composed of N-terminal amino acid residues 1–20 of human VEGF. In the present study, syncytiotrophoblast and invading extravillous trophoblasts ubiquitously...
Annexin I and II are calcium binding proteins implicated in the regulation of a number of cellular functions, including secretory processes, prolactin release and prostaglandin, formation. The cellular distribution of these proteins was examined in human term placenta, fetal membranes (amnion and chorion laeve) and decidua using immunohistochemistry. Annexin I was found in amnion epithelial cells...
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