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PubMed2001

An aspartic proteinase expressed in the yolk sac and neonatal stomach of the mouse.

A murine aspartic proteinase, described herein, is intermediate in amino acid sequence identity between the placentally produced pregnancy-associated glycoproteins (PAGs) and gastric pepsins. While PAGs are secreted products of placental trophoblast tissue of ungulates and most are not believed to function proteolytically, pepsins are digestive enzymes. The cDNA for this aspartic proteinase was amplified by reverse transcription-polymerase chain reaction from RNA extracted from murine placentas and neonatal stomachs. The open reading frame encoded a 387-amino acid polypeptide with a 15-residue signal sequence. The enzyme most resembled pepsinogen F (a protein identified in the stomachs of neonatal rabbits and rats) and PAG-like proteins cloned from equine and feline placentae. In the stomach, both its mRNA and protein were expressed in gastric chief cells of preweaned neonates. Within the placenta, its mRNA was present in both the parietal and visceral yolk sacs. However, the protein was most prevalent in the visceral yolk sac, with little detectable in the parietal yolk sac. The recombinant protein was expressed in Escherichia coli. This protein was capable of self-activation and exhibited proteolytic activity toward casein. The presence of this enzyme in two organs involved in the selective transcellular transport of proteins suggests that it has specialized digestive functions.

Amino Acid Sequence↗
PubMed1989

Effects of cellular transformation on expression of plasminogen activator inhibitors 1 and 2. Evidence for independent regulation.

Expression of plasminogen activators (PA) has been reported to be associated with invasive tumor growth and increased metastatic ability. In order to delineate changes in PA and PA inhibitor (PAI) expression that accompany cellular transformation, we studied oncogene-containing variants of the Rat-1 cell line. We report here that transfection of the oncogenes v-src, erbB, c-myc, v-myc, N-myc, and EJras into these cells does not result in detectable PA activity in conditioned media or cell extracts. In addition, Northern blot analysis fails to demonstrate urokinase mRNA in Rat-1 cells or transfectants. Moreover, cells transformed by EJras and v-src but not other oncogenes secrete an active placental-type PAI, PAI-2. Using inducible EJras constructs, we find that increased PAI-2 gene expression is detectable within 6-12 h after treatment with the inducing agent. Peak expression of PAI-2 mRNA is increased 10-15-fold over base line, and high levels are maintained for at least 72 h. In contrast to the results with PAI-2, secretion of endothelial-type PAI-1 into conditioned media is sharply down-regulated by several oncogenes. Thus, we have found that PAI-1 and PAI-2 are independently regulated in transformed variants of Rat-1 cells. The specific induction of PAI-2 in cells transformed by oncogenic ras and src suggests that this protease inhibitor may have a previously unsuspected role in malignancy.

Animals↗
PubMed1989

Partial purification of a luteotrophic substance from bovine fetal cotyledon granules.

To determine whether luteotrophic activity is present in the bovine placental granules, fetal cotyledons from fetuses of 50-100 days of gestation were used. Enriched granules were prepared using a Percoll gradient. Active substances were obtained from the granules by freeze-thawing. The extracts thus obtained were then eluted on a Sephacryl S-300 column. The resultant fractions were then analysed by (1) a radioreceptor assay for hCG-like substances and (2) a bioassay using progesterone production by bovine luteal cells. There were two peaks of activity, one indicative of a high molecular weight substance and the second of a low molecular weight substance. Higher molecular weight substances were eliminated by using acidic extracts. The low molecular weight fraction was further analysed using reverse phase h.p.l.c. (acetonitrile:water gradient). The elution of this substance at 45% acetonitrile resulted in a 100-fold increase in luteotrophic activity in the bioassay compared to the Sephacryl fraction. The small molecular weight substance is heat-stable and not extracted to the organic phase when partitioned between methanol and chloroform.

Animals↗
PubMedDate not supplied

[Value of antepartal cardiotocogram in risk pregnancies--comparative evaluation of the non-stress test and oxytocin stress test].

247 patients with risk of uteroplacental insufficiency were monitored by 434 oxytocin challenge tests (OCT) and non-stress-tests (NST). A non-reactive NST was found in 20% of the patients. Late decelerations in the OCT were observed in 19%. With respect to late decelerations and loss of reactivity in the OCT, the results of the stress tests were pathological in 29% of the patients. Based on the evaluation of late decelerations only, the OCT does not appear to be superior to the NST. Only when the reactivity criterion is additionally taken into account can the diagnostic rating of the OCT be given more value than that of the NST. Furthermore, it could be established that the loss of reactivity is of greater importance than late decelerations in the presence of reactivity.

Apgar Score↗
PubMed1980

Production of blood capillary contracting substance after administration of estrogen to rabbit.

Estradiol was continuously injected to female rabbits with a daily dose of 10,000 units for 50 days, and androgen was similarly given to male rabbits. Samples were obtained from livers of these rabbits according to the method of "placental capillary contracting substance", and their capillary contracting activities were determined. A substance showing a high activity was obtained from the liver of the rabbit treated with estradiol. A capillary contracting substance was also extracted from the urine of pregnant women, but it was hardly obtained from the urine of normal men.

Androgens↗
PubMed1998

Analysis of CpG islands of trophoblast giant cells by restriction landmark genomic scanning.

Rat trophoblast giant cells each contain at least 100 times more genomic DNA per nucleus than diploid cells. This unusual phenomenon appears to be of interest in relation to the molecular mechanism of cell differentiation and gene expression in the placenta. In the present study, we analyzed the CpG islands of trophoblast giant cells by restriction landmark genomic scanning (RLGS) using the methylation-sensitive landmark enzymes, Not I and Bss HII. More than 1,000 and 1,900 spots were detected by RLGS using Not I and Bss HII, respectively, in the placental junctional zone, where more than 90% of genomic DNA is present in the cells with higher DNA content. Of these, 97% (1,009 spots) and 99% (1,911 spots) of the spots found in the junctional zone showed an identical pattern and identical intensity with those of diploid cell controls, for which genomic DNA was extracted from the labyrinth zone and maternal kidney. Therefore, the giant cells are basically polyploid. More importantly, 24 tissue-specific spots were detected by RLGS using Not I. Subsequent cloning and sequencing of four typical spots of the genomic DNA confirmed that these DNA fragments contained abundant CpG dinucleotides and showed characteristics of CpG islands. Of these 24 spots, there were ten spots specific for the placenta, and three of them were specific for the junctional zone, indicating that methylation status of CpG islands in the placental tissue differed between the junctional zone and labyrinth zone. These results suggest that multiple rounds of endoreduplication and modification of CpG islands by cytosine methylation occur during the differentiation process of giant cells.

Animals↗
PubMed1996

Purification of acid sphingomyelinase from human placenta: characterization and N-terminal sequence.

Human placental acid sphingomyelinase (ASM) was purified by sequential chromatography on Con A-Sepharose, octyl-Sepharose and Matrex gel red A. Final purification to apparent homogeneity was achieved by immunoaffinity chromatography employing polyclonal anti-ASM antibodies. The antibodies also allowed specific detection of ASM by Western blotting at various stages of purification. The ASM activity was enriched about 110,000-fold over that of the crude extract, yielding an enzyme preparation with a specific activity of about 1 mmol/h per mg protein in a detergent-containing assay system. Analysis of the final preparation by SDS-PAGE resulted in a single protein band with a molecular mass of approximately 75 kDa, which was reduced to approximately 60 kDa after complete deglycosylation. Microsequencing of the purified ASM revealed the N-terminal amino acid sequence of the mature placental enzyme.

Amino Acid Sequence↗
PubMed1999

Elevated level of free 8-iso-prostaglandin F2alpha in the decidua basalis of women with preeclampsia.

OBJECTIVES: The prostaglandin-like compound 8-iso-prostaglandin F(2alpha) represents an index of oxidative stress and has the ability to induce endothelial derangement, platelet activation, and vasoconstriction. In women with preeclampsia the decidual spiral arteries contain lipid deposits (acute atherosis). Analogously to the elevated level of 8-iso-prostaglandin F(2alpha) demonstrated in atherosclerotic lesions, we hypothesized that 8-iso-prostaglandin F(2alpha) level would be elevated in preeclamptic decidua basalis tissues. STUDY DESIGN: Decidua basalis tissues were obtained by vacuum aspiration and placental tissues were obtained by excision at cesarean delivery from 16 preeclamptic and 15 normal pregnancies. Total and free 8-iso-prostaglandin F(2alpha) concentrations were quantified with an enzyme immunoassay technique after lipid extraction and separation. RESULTS: The content of free 8-iso-prostaglandin F(2alpha) in preeclamptic decidual tissues was found to be significantly elevated with respect to that in control tissues. The content of total 8-iso-prostaglandin F(2alpha) did not differ significantly between the groups in either placenta or decidua basalis. CONCLUSIONS: We propose that free 8-iso-prostaglandin F(2alpha) released from the decidua basalis in preeclampsia may mediate maternal vascular dysfunction and platelet activation.

Adult↗
PubMed1979

Cation transport across the guinea-pig placenta perfused in situ.

1. The guinea-pig placenta perfused in situ via the umbilical circulation has been used to measure unidirectional fluxes of Na from mother to fetus, and in the reverse direction, with 24Na and 22Na. There was no significant difference between the two fluxes, each being 22 mumole.min-1. 2. Ouabain 10(-5) M in the perfusion fluid had no detectable effect on radioisotopic movements of Na in either direction. 3. Unidirectional fluxes of 42K in both directions were approximately equal at 1.7 mumole.min-1 mother fetus and 1.8 mumole.min-1 in the reverse direction, despite a K concentration of 3.4 mM on the maternal side and 5.0 mM on the fetal side of the placenta. 4. Extraction of 42K and 86Rb from the perfusion fluid was inhibited by 43% by 10(-5) M-ouabain in the fluid. This effect was largely due to a reduction of isotope uptake by the placental tissue. 5. The relative permeabilities of the placenta, mother to fetus, were Rb approximately K (3.2) greater than Na (1.0) greater than Li (0.55). 6. Under the experimental conditions, the electrical potential difference between perfusion fluid and maternal blood was 6 mV (fetus negative). It was shifted towards the positive by a low Na fluid. 7. The results suggest the presence of a dominant Na-K pump (active component towards mother) sited at the maternal-facing membrane of the syncytiotrophoblast together with a subsidiary pump oriented in the opposite direction and probably sited together with a subsidiary pump oriented in the opposite direction and probably sited at the fetal-facing membrane of the syncytiotrophoblast. 8. A high proportion of Na movement particularly towards the fetus is probably passive, occurring through water-filled spaces, whilst K movement is more dependent on active transport.

Animals↗
PubMed2004

Placenta accreta and intrauterine fetal death in a woman with prior endometrial ablation: a case report.

BACKGROUND: Few cases of pregnancy following endometrial ablation have been reported. Placenta accreta and poor perinatal outcome are potential risks due to underlying endometrial destruction and uterine scarring. CASE: A 41-year-old, white woman presented for initial prenatal care at 12 weeks, 3 years after endometrial ablation with resection of a leiomyoma. The patient's prenatal care was unremarkable until 20 weeks, when she presented with intrauterine fetal death. Labor was induced with misoprostol, and a stillborn fetus resulted. The placenta failed to deliver spontaneously after 6 hours and continuing doses of misoprostol. An attempt at manual extraction failed to demonstrate a clear cleavage plane between the placenta and endometrium. The patient underwent a hysterectomy for placenta accreta, which was confirmed on pathology. CONCLUSION: Endometrial ablation may predispose the patient to abnormal placentation and intrauterine fetal death. Physicians should counsel their patients appropriately about the likelihood of this outcome.

Adult↗
PubMedDate not supplied

[Late postpartum hemorrhage].

In the presented material the frequency of postpartum haemorrhage is 0.74%. In the study sixty-nine histologically confirmed cases were considered. At histological examination three main factors were found--subinvolution of the placental site, retained placental tissue, and inflammation, each of them responsible for about one third of all cases. The possible influence of such factors as parity, time of delivery, frequency of caesarian section, frequency of intrauterine exploration, manual extraction of the placenta, and induction and stimulation of the delivery on late postpartum haemorrhage is discussed.

Female↗
PubMed1988

Calcitonin-like immunoreactivity and calcitonin gene expression in the placenta and in the mammary gland of the rat.

Recently, the presence of monomeric CT in plasma and milk was reported by others in a lactating woman surgically thyroidectomized. Similarly, the placenta was thought to be a possible source of CT. Since such findings were based exclusively on immunological arguments, we have investigated the CT gene expression in these rat tissues. CT mRNAs were detected by dot-blot hybridization of total RNAs extracted from rat tissues with a 32P-labelled human CT cDNA probe. Subcellular fractions of each tissue were screened for CT-like immunoreactivity using two different antibodies. With one antibody, extracts of the mammary gland and placenta both produced full displacement of labelled human CT from the antiserum and serial dilutions of the extracts gave displacement curves parallel to that of synthetic human CT, which suggests immunological similarity. However, dilution curves were not parallel for the second antibody, and for both antisera, CT-like immunoreactivity was found in all subsellular fractions from nuclei to cytosols. Immunoprecipitation of translation products from poly (A)+RNAs of placenta showed two major bands around 30 kD. Under stringent conditions, the weak hybridization of placental RNAs seen by dot-blot under less stringent conditions disappeared. Northern analyses of total RNAs from the placenta failed to detect mRNA of 1 k base size like in thyroid glands, but hybridization under weak stringent conditions occurred with larger mRNAs (around 4.4 and 2.4 k bases). Immunoprecipitation of translation products from mRNAs of rat mammary glands showed three major bands around 46, 30 and 20 kD. Dot-blot hybridization of total RNAs extracted from mammary glands was also negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Effect of maternal serum on viability and function of early human placental explants.

Fetal bovine serum (FBS) is frequently used to supplement chemically defined media such as Ham's F10 when studying placental explant cultures. However in vitro production of hormones is usually declining by the 2nd or 3rd day and is short-lived (7 to 10 days). In this study we explored the use of human maternal serum (HMS) from early gestation as the medium supplement to Ham's F10. Early placental hormone production was compared using two concentrations of FBS and HMS. On Day 3 of incubation, progesterone production in 10% HMS was 12-fold increased over that in 10% FBS, estradiol production was increased 10-fold, and beta hCG production more than 3-fold. When the serum concentrations were increased to 40%, the results in all cases were similar to those at 10%. Preliminary characterization studies revealed that the stimulatory activity of HMS is heat-labile, neither extractable into organic solvent (diethyl ether) nor dialyzable, suggesting that it is protein in nature. In a long-term incubation, compared with FBS (7 days), HMS permitted survival of culture up to 30 days, judged both histologically and biochemically. We conclude that HMS provides substance(s), probably protein in nature, not present in FBS or non-pregnant human serum, which are important for human placental viability and function in vivo.

Blood Physiological Phenomena↗
PubMed1999

Production of recombinant proteins in plant root exudates.

The large-scale production of recombinant proteins in plants is limited by relatively low yields and difficulties in extraction and purification. These problems were addressed by engineering tobacco plants to continuously secrete recombinant proteins from their roots into a simple hydroponic medium. Three heterologous proteins of diverse origins (green fluorescent protein of jellyfish, human placental alkaline phosphatase [SEAP], and bacterial xylanase) were produced using the root secretion method (rhizosecretion). Protein secretion was dependent on the presence of the endoplasmic reticulum signal peptide fused to the recombinant protein sequence. All three secreted proteins retained their biological activity and, as shown for SEAP, accumulated in much higher amounts in the medium than in the root tissue.

Alkaline Phosphatase↗
PubMed2004

Association of -634G/C and 936C/T polymorphisms of the vascular endothelial growth factor with spontaneous preterm delivery.

BACKGROUND: There is convincing evidence for a central role of vascular endothelial growth factor (VEGF) in fetal and placental angiogenesis. Our present study was undertaken to examine the possible relationship between two common functional VEGF gene polymorphisms (- 634G/C and 936C/T), linked with altered VEGF gene responsiveness, and spontaneous preterm delivery. METHODS: Genomic DNA was extracted from whole blood from 54 women with preterm labor and 79 menopausal women with at least two term spontaneous labors. DNA samples were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Individuals with 936T/T or 936C/T genotype demonstrated a statistically significant association with preterm delivery compared with those sharing 936C/C genotype [P = 0.0009, risk factor 2.05, 95% confidence interval (CI) 1.37-3.06]. There were no significant associations between spontaneous preterm delivery and - 634 genotypes. CONCLUSION: An association was demonstrated between the VEGF 936C/T polymorphism and deliveries before 37 weeks of gestation.

Adult↗
PubMed2003

Placental growth factor, a member of the VEGF family, contributes to the development of choroidal neovascularization.

PURPOSE: VEGF has been shown to be necessary, but not sufficient alone, for the development of subretinal pathologic angiogenesis. In the current study, the influence of placental growth factor (PlGF), a member of the VEGF family, in human and experimental choroidal neovascularization (CNV) was investigated. METHODS: The presence of VEGF family member mRNA was evaluated by RT-PCR in neovascular membranes extracted during surgery. The spatial and temporal pattern of VEGF isoforms and PlGF mRNA expression were explored by using the laser capture catapulting technique and RT-PCR in a murine laser-induced model and in vitro. PlGF expression was also studied in human donor eyes. The influence of endogenous PlGF was evaluated in deficient mice (PlGF(-/-)) and by antibody-mediated neutralization of the PlGF receptor. RESULTS: Human neovascular membranes consistently expressed VEGF-A, -B, and -C; PlGF; and VEGFR-1 and -2. The VEGF(120) isoform mRNA was primarily induced in early stages of angiogenesis in vivo and in vitro. PlGF mRNA expression was present in the intact choroid and significantly upregulated during the course of experimental CNV. Both deficient PlGF expression in PlGF(-/-) mice and PlGF receptor neutralization in wild-type mice prevented the development of choroidal neovascularization induced by laser. CONCLUSIONS: These observations demonstrate the participation of PlGF in experimental CNV. They identify therefore PlGF as an additional promising target for ocular antiangiogenic strategies.

Angiogenesis Inducing Agents↗