Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PLACENTAL EXTRACTS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 721 records · Page 40Linked to original sources
PubMedDate not supplied

Developmental expression of vascular endothelial growth factor and its receptors in ovine placenta and fetal membranes.

OBJECTIVES: Vascularity of the surface of the placenta in humans and of the placenta and fetal membranes in several species including sheep is an important determinant of intramembranous absorption of amniotic fluid. Our previous studies have shown that the total blood vessel surface area in ovine amnion and chorion increases with advancing gestation. Vascular endothelial growth factor (VEGF) is a potent angiogenic and permeability factor and is found to be expressed in the ovine placenta and fetal membranes. To investigate the role of VEGF in maintaining the absorptive function of the intramembranous microvessels, the present study was undertaken to determine the gestational change in gene expression of VEGF and its receptors, kinase insert domain-containing receptor (KDR) and fms-like tyrosine kinase (Flt-1), in ovine placenta, chorion, and amnion. METHODS: Total RNA was extracted from placental cotyledon, chorion, and amnion of ovine fetuses at 60-140 days of gestation. The relative abundance of VEGF, KDR, and Flt-1 mRNA was determined by Northern blot analysis, and VEGF molecular forms expressed were identified by reverse transcriptase polymerase chain reaction. The gestational changes in mRNA levels of VEGF and its receptors were analyzed by regression analysis. RESULTS: In ovine placenta, chorion, and amnion, VEGF mRNA levels increased significantly from 60 to 140 days. The major VEGF molecular form expressed in these tissues was VEGF164, whereas VEGF120, VEGF144, and VEGF188 were present at lower levels. In the placenta, KDR was the primary VEGF receptor expressed, although Flt-1 was also detected at very low levels. In the amnion and chorion, KDR was the only receptor expressed. A gestational-dependent change in VEGF receptor expression was not observed in the placenta and membranes. CONCLUSIONS: The increase in VEGF gene expression with advancing gestation in the amnion and chorion where KDR is expressed suggests that VEGF and its receptor are important determinants of vascularity and permeability, and thus exchange capacity, of the intramembranous pathway.

Amnion↗
PubMed1988

Isolation of multiple forms of DNA polymerase delta: evidence of proteolytic modification during isolation.

The subunit structures of a number of human placenta DNA polymerase delta preparations were investigated by Western blotting with polyclonal antisera and by activity staining following polyacrylamide gel electrophoresis. When immunoblots and activity stains were performed on different enzyme preparations, putative catalytic subunits of (a) 170, (b) 120, or (c) 50-70 kilodaltons (kDa) were observed. It was also observed that the lower molecular weight forms could be generated upon storage of the preparations. Western blotting of human placental tissue extracts showed that the major immunoreactive polypeptide was 160-170 kDa. Treatment of the extracts with trypsin or Staphylococcus aureus V8 protease led to the generation of immunoreactive polypeptides of lower molecular weights. These studies suggest that the 120-kDa and lower forms of the enzyme are generated via uncontrolled proteolysis and provide a rationale for the observation of different apparent subunit structures previously reported for DNA polymerase delta. In addition, these findings suggest that DNA polymerase delta has a catalytic domain which resides in a protease-resistant domain.

DNA Polymerase III↗
PubMed1999

Three TRH-like molecules are released from rat hypothalamus in vitro.

TRH-like immunoreactivity distinct from TRH is present in various tissues and fluids. In order to determine whether TRH-like molecules are secreted by the hypothalamus, we analyzed tissues and media from hypothalamic slices incubated in Krebs Ringer bicarbonate. Media from basal or high KCl conditions contained 3 TRH-like molecules evidenced by reverse phase high performance liquid chromatography followed by TRH radioimmunoassay. Peak I corresponded to authentic TRH (73% of total immunoreactivity) and peaks II and III had a higher retention time. These additional TRH-like forms were neither detected in hypothalamic tissue nor in tissue or medium from olfactory bulb. Gel filtration analysis of hypothalamic media revealed only one TRH-like peak eluting as TRH, suggesting that the molecular weights of peaks II and III are similar to that of TRH. Peak II retention time was similar to that of pglu-phe-proNH2. We analysed if they could be produced by post secretory metabolism of TRH. Incubation of hypothalamic slices with [3H-Pro]-TRH did not produce radioactive species comigrating with peaks II or III. However, it induced rapid degradation to [3H-Pro]-his-prodiketopiperazine ([3H]-HPDKP). Inhibitor profile suggested that pyroglutamyl aminopeptidase II, but not pyroglutamyl aminopeptidase I, is responsible for [3H]-HPDKP production. These data are consistent with the hypothesis that pyroglutamyl aminopeptidase II is the main aminopeptidase degrading TRH in hypothalamic extracellular fluid. Furthermore, we suggest that the hypothalamus releases additional TRH-like molecules, one of them possibly pglu-phe-proNH2, which may participate in control of adenohypophyseal secretions.

Aminopeptidases↗
PubMed2001

Influence of labor on fetoplacental adrenomedullin concentrations.

OBJECTIVE: Circulating adrenomedullin is increased in pregnancy, and placental and fetal membranes participate significantly in its secretion. Recent studies have suggested a potential role for this peptide in the regulation of fetoplacental circulation and placental hormonal secretion. Because adrenomedullin acts also as a uterorelaxant in rats, this study was designed to investigate whether fetoplacental adrenomedullin production changes with human labor, either at term or preterm. STUDY DESIGN: Eighty pregnant women grouped according to gestational age and presence of labor were studied. Adrenomedullin concentrations in plasma, amniotic fluid, and placental tissue extracts were measured by means of radioimmunoassay and immunohistochemistry. In addition, the ability of amnion and chorion-decidua to secrete adrenomedullin was investigated in vitro. RESULTS: Adrenomedullin concentrations in amniotic fluid were higher in preterm labor, whereas no differences were found in adrenomedullin expression or concentrations in tissues or in maternal and fetal plasma between vaginal delivery or elective cesarean section, both at term and preterm. During term labor (8 patients), maternal plasma adrenomedullin concentration decreased with advancing cervical dilatation, being 173 pg/mL at the beginning of the active stage of labor and 57 pg/mL at the time of delivery. Adrenomedullin concentration in the medium of amnion- and chorion-decidua-cultured cells was higher after vaginal delivery. CONCLUSION: These results suggest that a decrease in adrenomedullin production is not involved in the onset of labor in human subjects but rather that it may play a role other than that of a myometrial relaxant in human parturition.

Adrenomedullin↗
PubMed2001

The membrane-type collectin CL-P1 is a scavenger receptor on vascular endothelial cells.

Collectins are a family of C-type lectins that have collagen-like sequences and carbohydrate recognition domains (CRD). They are involved in host defense through their ability to bind to carbohydrate antigens of microorganisms. The scavenger receptors type A and MARCO are classical type scavenger receptors that have internal collagen-like domains. Here we describe a new scavenger receptor that is a membrane-type collectin from placenta (collectin placenta 1 (CL-P1)), which has a typical collectin collagen-like domain and a CRD. The cDNA has an insert of about 2.2 kilobases coding for a protein containing 742 amino acid residues. The deduced amino acid sequence shows that CL-P1 is a type II membrane protein, has a coiled-coil region, a collagen-like domain, and a CRD. It resembles type A scavenger receptors because the scavenger receptor cysteine-rich domain is replaced by a CRD. Northern analyses, reverse transcription-polymerase chain reaction, and immunohistochemistry show that CL-P1 is expressed in vascular endothelial cells but not in macrophages. By immunoblotting and flow cytometry CL-P1 appears to be a membrane glycoprotein of about 140 kDa in human umbilical vein or arterial endothelial cells, placental membrane extracts, and CL-P1 transfected Chinese hamster ovary cells. We found that CL-P1 can bind and phagocytose not only bacteria (Escherichia coli and Staphylococcus aureus) but also yeast (Saccharomyces cerevisiae). Furthermore, it reacts with oxidized low density lipoprotein (OxLDL) but not with acetylated LDL (AcLDL). These binding activities are inhibited by polyanionic ligands (polyinosinic acid, polyguanylic acid, dextran sulfate) and OxLDL but not by polycationic ligands (polyadenylic acid or polycytidylic acid), LDL, or AcLDL. These results indicate that CL-P1 might play important roles in host defenses that are different from those of soluble collectins in innate immunity.

Amino Acid Sequence↗
PubMed1971

Immunohistological and elution studies of the human placenta.

An immunohistological survey of 28 full-term human placentas has demonstrated deposits of IgG, beta1C, beta1E, and fibrinogen/fibrin in areas of fibrinoid necrosis and on the trophoblast basement membrane in approximately 35% of placental villi. Traces of IgM were detected at similar sites in 18 of 28 full-term placentas. In 11 specimens of immature placentas (10-18 wk gestation) traces of IgG and beta1C and deposits of fibrinogen/fibrin were also present, but IgM was not detected in this material. IgG was recovered in acidic eluates from an homogenized placenta which behaved as an antibody reactive with unidentified material present in fibrinoid deposits and on the thickened trophoblast basement membrane of some villi. It could not be determined whether this IgG was derived from the maternal or fetal circulation.

Basement Membrane↗
PubMed1984

Localization of a molecule immunochemically similar to eosinophil major basic protein in human placenta.

We have recently reported that human pregnancy is characterized by a 10- to 20-fold elevation of eosinophil major basic protein (MBP) immunoreactivity in maternal blood. Here we show, by immunofluorescence, that placental tissue specifically binds antibody to MBP in and around the placental X cells and placental-site giant cells and, using thin plastic sections, that placenta has no infiltrating eosinophils. The X cells line the inner aspects of placental septal cysts, and the cyst fluid, obtained by aspiration, contains immunoreactive MBP at concentrations of 100 micrograms/ml, a sixfold greater concentration than the highest levels measured in maternal blood. The soluble MBP immunoreactivities in placental homogenates and in maternal serum chromatograph identically on Sephadex G-50, and both these gestational MBP molecules migrate as though substantially larger than the MBP found in serum from patients with hypereosinophilic syndrome or purified from the eosinophil granule. Our inability to demonstrate eosinophils in maternal blood or placental tissue, coupled with the large quantities of immunoreactive MBP highly localized in placental cysts and the chromatographic behavior of this molecule, suggest that the MBP detected in human gestation is produced by placenta.

Animals↗