Effect of locoweed (Astragalus ientiginosus) feeding of fetal lamb development.
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Locoweed, Astragalus lentiginosus, was fed to pregnant ewes for various periods during gestation. The principal gross effects on the developing fetuses were observed to be delayed placentation, decreased vascularization, fetal edema and hemorrhage, and alteration of cotyledon development. Deformed lambs and undersized lambs also occurred. Data from sheep fed locoweed during various periods of the entire gestation period are summarized and indicate that locoweed poisoning in the fetus as with the adult is a chronic type of intoxication. Also, poisoning of the fetus parallels poisoning in the dam. (+info)
Alternative forms of a novel aspartyl protease gene are differentially expressed in human gestational tissues.
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The aim of this study was to identify genes involved in human placentation. To do this, differential gene expression was assessed in the decidua (placental bed) from pre-eclamptic and normotensive pregnancies using the polymerase chain reaction (PCR)-based subtractive technique of representational difference analysis. A novel aspartyl protease (cathepsin D-like) cDNA sequence was isolated by virtue of its over-expression in the pre-eclamptic decidual sample tested. It was designated DAP-1 (for Decidual Aspartyl Protease 1). Using DAP-1 primer sequences a second cDNA (DAP-2) was subsequently isolated from decidual RNA by reverse transcription (RT)-PCR and found to be identical to DAP-1 apart from 80 additional and consecutive base pairs in the N-terminal coding region. In DAP-2, a stop codon within the unique 80 bp sequence was predicted to terminate translation immediately before the consensus active site residues. While Southern blotting was used to show that there are two loci with homology to DAP-1 in the human genome, it is postulated that alternative pre-mRNA splicing of the 80 bp exon is involved in the regulated expression of active (DAP-1) and inactive (DAP-2) forms of this novel protease; a mechanism similar to that involved in the regulated expression of Caspase-2, a protease involved in apoptosis. In other systems the regulation of alternative splicing is indicated by tissue specificity and developmental stage specificity of the various spliced products. In this context it was demonstrated that whereas DAP-1 was the major transcript expressed in decidua, the pattern was reversed in the adjacent placental tissue. It is proposed that tissue and developmental stage-specific expression of the DAP protease are important for the normal development and function of the uteroplacental tissues and that dysregulation of the control of DAP gene splicing may play a role in abnormal placentation, like that seen in pre-eclampsia. (+info)
The role of insulin-like growth factor binding protein-1 phosphoisoforms in pregnancies with impaired placental function identified by doppler ultrasound.
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This study was performed to investigate the hypothesis that insulin-like growth factor binding protein-1 (IGFBP-1) is involved in the pathogenesis of trophoblast invasion and impaired placentation in human pregnancy. The role of total and non-phosphorylated IGFBP-1 in women with fetal growth restriction and in high risk pregnancies identified by uterine artery Doppler ultrasound screening was examined. This was a prospective study of women booked for antenatal care having second trimester anomaly scans and Doppler screening between 22-26 weeks gestation. Women were divided into three groups and compared: normal uterine artery Doppler and normal fetal growth (control group, n = 10); abnormal Doppler and normal fetal growth [bilateral uterine artery notches (BN; n = 16); abnormal Doppler and intrauterine growth restriction (IUGR; n = 8)]. Maternal serum was collected, stored and assayed simultaneously for total and non-phosphorylated IGFBP-1. There was elevated total and non-phosphorylated IGFBP-1 (mean 44.99 +/- 12.19 and 29.61 +/- 10.38 microg/l respectively) in the IUGR group compared with controls (mean 17.96 +/- 3.24 and 12.18 +/- 1.55 microg/l, P < 0.05). This finding suggests that the various IGFBP-1 isoforms, the degree of phosphorylation and the ratios of these different forms locally may be important during trophoblast invasion and may be implicated in clinical manifestations of impaired placentation later in the second trimester. (+info)
Cell death of uterine natural killer cells in murine placenta during placentation and preterm periods.
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In the murine uterus granulated metrial gland (GMG) cells appear only during normal pregnancy. GMG cells belong to a member of natural killer (NK) cells and play an important role in fetus survival and placental growth. Our previous study revealed that mouse GMG/uterine NK (uNK) cells in the late pregnancy rapidly disappear from the uterus, due to the degenerative change classified as necrosis. But there are few reports regarding appearance and morphology of uNK cells during late pregnancy. We examined histologically and histochemically how and when uNK cells undergo cell death. The uNK cells in the metrial gland increased in number and reached maximum until day 12 of pregnancy. Sudden disappearance, however, occurred after day 15 and the granules reduced in both number and size. In situ DNA fragmentation detection revealed that DNA fragmented uNK cells increased in number during days 13 to 15 and reached 70.2% at day 15 of pregnancy. From days 13 to 17, uNK cells were positive against anti-perforin antibody. Ultrastructurally, uNK cells at day 15 showed poor organelles and unusual granules in structure. In uNK cells at day 17, condensation of nucleus chromatin, reduction in size and phagocytosis into other uNK cells were observed. These results suggested that uNK cells undergo at least two types of cell death, classified as necrosis and apoptosis, at the different stages of pregnancy, and that perforin is not a mediator for cell death. (+info)
Expression of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) in conceptus and endometrium during implantation in the rhesus monkey.
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The aim of this study was to analyse the expression of transcripts and proteins for vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) in different compartments of the early conceptus at primary implantation sites during lacunar (n = 6), early villous (n = 9) and villous placenta (n = 6) stages of gestation in the rhesus monkey. During the lacunar stage, VEGF expression was observed in the cytotrophoblast cells lining the extraembryonic cavity, but these cells did not express PlGF. With further development, cytotrophoblast cells lining villi, forming columns, and constituting anchoring villi, expressed both VEGF and PlGF during early villous and villous placenta stages. In addition, chorion, amnion and villous stromal cells expressed both VEGF and PlGF proteins and mRNA. During the lacunar stage, all epithelial cells in maternal endometrium generally expressed VEGF, while PlGF expression was observed in the plaque epithelium only. As gestation advanced, the expression of VEGF and PlGF from plaque cells decreased, and in surface and glandular epithelium the expression of VEGF increased, while the expression of PlGF remained unaltered. Decidual stromal cells expressed VEGF and PlGF only at low levels during the lacunar stage, while the expression of both increased during the early villous and the villous placenta stages of implantation. It appears from the present study that the expression of VEGF and PlGF are regulated in a temporal and spatial manner during early stages of implantation and that their concerted actions in placental and maternal compartments play a critical role in the evolving pregnancy in the rhesus monkey. (+info)
Fetomaternal interactions and influences during equine pregnancy.
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The equine embryo takes 6 days to traverse the oviduct and, when it finally enters the uterus, it remains spherical in shape and moves continually throughout the uterine lumen until day 17 after ovulation to deliver its maternal recognition of pregnancy signal to the entire endometrium. Between day 25 and day 35 after ovulation, the trophoblast cells of a discrete annulate portion of the chorion multiply rapidly and acquire an invasive phenotype and, between day 36 and day 38, migrate deeply into the maternal endometrium to form the equine-unique endometrial protuberances known as endometrial cups. These cups secrete large quantities of a gonadotrophic hormone (eCG) into the maternal circulation which, in conjunction with pituitary FSH, stimulates the development of accessory luteal structures in the maternal ovaries to supplement the supply of progesterone to maintain the pregnancy until the placenta can assume this role at about day 100. The non-invasive allantochorion extends slowly to fill the uterus by days 80-85 and its microcotyledonary architecture, which provides both haemotrophic and histotrophic nutrition for the growing fetus, is not fully established until days 120-140. The fetoplacental unit synthesizes large quantities of steroid hormones during the second half of pregnancy, using fetal C-19 precursors secreted by the enlarged fetal gonads for the production of oestrogens and maternal C-21 precursors for the synthesis of progesterone and large quantities of 5alpha-reduced progestagens. Near term, additional pregnenelone is secreted by the fetal adrenal glands so that the mare exhibits the unusual phenomenon of foaling while maternal serum progestagen concentrations are increasing and oestrogen concentrations are decreasing. (+info)
Hemochorial placentation in the primate: expression of vascular endothelial growth factor, angiopoietins, and their receptors throughout pregnancy.
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Vascular development and its transformation are necessary for successful hemochorial placentation, and vascular endothelial growth factor (VEGF), angiopoietins, and their receptors may be involved in the molecular regulation of this process. To determine the potential role of these putative regulators in a widely studied primate, the common marmoset, we investigated their mRNA expression and protein location in the placenta throughout pregnancy using in situ hybridization, Northern blot analysis, and immunocytochemistry. VEGF was localized in decidual and cytotrophoblast cells, and its highest expression was found in the maternal decidua. The Flt receptor was exclusively detected in the syncytial trophoblast with increasing expression in placentae from 10 wk to term. Soluble Flt (sFlt) was also detectable by Northern blot analysis. KDR receptor expression was restricted to mesenchymal cells during early placentation and to the fetoplacental vasculature during later placentation. KDR expression increased throughout pregnancy. Angiopoietin-1 (Ang-1) was localized in the syncytial trophoblast, being highly expressed in the second half of gestation. Ang-2 mRNA localized exclusively to maternal endothelial cells, and was highly expressed in 10-wk placentae. The Tie-2 receptor was found in cytotrophoblast cells and in fetal and maternal vessels. High Tie-2 levels were detected in the wall of chorion vessels at 14-wk, 17-wk, and term placentae. These results suggest that the processes of trophoblast invasion, maternal vascular transformation, and fetoplacental vascular differentiation and development are regulated by the specific actions of angiogenic ligand-receptor pairs. Specifically, 1) VEGF/Flt and Ang-1/Tie-2 may promote trophoblast growth, 2) VEGF/KDR and Ang-1/Tie-2 may support fetoplacental vascular development and stabilization, 3) sFlt may balance VEGF actions, and 4) Ang-2/Tie-2 may remodel the maternal vasculature. (+info)
Expression of fertilin and CD9 in bovine trophoblast and endometrium during implantation.
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The superficial placentation of cattle involves the development of fetal binucleate cells that arise from the chorion and migrate between adjacent cell tight junctions to fuse with maternal epithelium. Thus, the temporal and spatial patterns of expression of the cell migration, adhesion, and fusion molecules fertilin and CD9 were investigated in bovine trophoblast and endometrium. Bovine fertilin alpha and fertilin beta messenger RNA sequences were amplified by reverse transcriptase-polymerase chain reaction in testis (positive control), peri-implantation (Days 18, 19, and 21), and postimplantation (Days 35-40) trophoblast RNA, but not in caruncular endometrium (Day 40). Northern blot analysis indicated that the transcript hybridizing to fertilin alpha in trophoblast RNA was approximately 4.0 kilobases (kb), whereas in testis, 2 transcripts of approximately 3.3 and 3.8 kb were indicated. The transcript hybridizing to the fertilin beta probe was also larger in trophoblast than in testis ( approximately 3.8 vs. 2.4 kb, respectively). In situ hybridization revealed that fertilin beta mRNA was expressed by trophoblast cells, including binucleate cells. Immunohistochemical study of CD9, a member of the transmembrane-4-superfamily which is thought to be involved in sperm-egg fusion, showed that CD9 was present on the apical surface of uterine epithelium and in a subpopulation of binucleate cells of the trophoblast. Immunoprecipitation followed by Western blot analysis showed association between CD9 and integrin alpha3 in endometrium. The results support the hypothesis that fertilin and CD9 are involved in bovine binucleate cell migration and fusion. (+info)