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PubMed1986

Immobilization of factor XIII on collagen membranes.

Factor XIII from placenta was successfully grafted onto collagen membranes by the acyl-azide procedure. The transamidase activity retained on collagen membranes was determined by measuring the increase of fluorescence resulting from dansylcadaverine incorporation into casein. We studied the effect of different factors on the grafting: concentration and composition of the factor XIII preparation in the coupling solution and influence of the preactivation of factor XIII by thrombin. Stability studies have shown that the activity of factor XIII grafted on collagen membranes was almost constant over a period of 8 months. Sterilization by gamma-irradiation of factor XIII revealed a drastic loss of activity while the use of high-energized electron bombardment caused a reduced loss of activity. The potential of such a material for biomedical use is presently under investigation.

Animals↗
PubMed2003

Correlations from gadopentetate dimeglumine-enhanced magnetic resonance imaging after methotrexate chemotherapy for hemorrhagic placenta increta.

OBJECTIVE: To describe pre- and post-methotrexate (MTX) therapy images from pelvic magnetic resonance imaging (MRI) with gadopentetate dimeglumine contrast following chemotherapy for post-partum hemorrhage secondary to placenta increta. MATERIAL AND METHOD: A 28-year-old Caucasian female presented 4 weeks post-partum complaining of intermittent vaginal bleeding. She underwent dilatation and curettage immediately after vaginal delivery for suspected retained placental tissue but 28 d after delivery, the serum beta-hCG persisted at 156 IU/mL. Office transvaginal sonogram (4 mHz B-mode) was performed, followed by pelvic MRI using a 1.5 Tesla instrument after administration of gadolinium-based contrast agent. MTX was administered intramuscularly, and MRI was repeated four weeks later. RESULTS: While transvaginal sonogram suggested retained products of conception confined to the endometrial compartment, an irregular 53 x 34 x 28 mm heterogeneous intrauterine mass was noted on MRI to extend into the anterior myometrium, consistent with placenta increta. Vaginal bleeding diminished following MTX treatment, with complete discontinuation of bleeding achieved by ~20 d post-injection. MRI using identical technique one month later showed complete resolution of the uterine lesion. Serum beta-hCG was <5 IU/mL. CONCLUSION: Reduction or elimination of risks associated with surgical management of placenta increta is important to preserve uterine function and reproductive potential. For selected hemodynamically stable patients, placenta increta may be treated non-operatively with MTX as described here. A satisfactory response to MTX can be ascertained by serum hCG measurements with pre- and post-treatment pelvic MRI with gadopentetate dimeglumine enhancement, which offers advantages over standard transvaginal sonography.

Journal Article↗
PubMed1991

Curettage after midtrimester termination of pregnancy. Is it necessary?

We conducted a prospective study to assess the need for curettage after spontaneous expulsion of the placenta in midtrimester termination of pregnancy. The rate of early complications (9.4%) was consistent with previously reported data. A higher incidence of intrauterine adhesions, detected on hysteroscopy, was observed in patients who underwent curettage (38.5% vs. 7.7%, P = .0727). In order to prevent intrauterine adhesions, curettage should be restricted to cases in which retained products of conception are suspected. It should not be performed routinely in every case of midtrimester termination of pregnancy after spontaneous expulsion of the placenta.

Abortion, Spontaneous↗
PubMed1983

Aromatase activity of steroid sulphatase-deficient placentae.

Aromatase activity was measured in homogenates from steroid sulphatase deficient and steroid sulphatase positive placentae. The activity of the aromatase complex was determined from the rate of formation of [14C] oestrone plus [14C] oestradiol when [14C] testosterone was incubated with a rate-limiting quantity of homogenate. A reduced level of aromatase activity was found in vitro in 70% of steroid sulphatase-deficient placentae tested, but the deficiency was much less complete than that of steroid sulphatase. The mean (+/- SD) aromatase activity of steroid sulphatase-deficient placentae was 380 +/- 180 pmol product/h/g tissue (n = 10), significantly lower (P less than 0.001, t-test) than the mean aromatase activity of steroid sulphatase positive placentae (701 +/- 70 pmol product/h/g tissue, n = 10). Seventy per cent of the steroid sulphatase deficient placentae showed lower aromatase activity than that of normal placentae stored for a comparable period of time. Assay imprecision and the sex of the foetus were excluded as reasons for the diminished aromatase activity found. It may arise through an abnormal gene product and consequent alterations in the structure of the microsomal membrane in which both aromatase complex and steroid sulphatase enzymes are retained.

Acetylation↗
PubMed1983

Inhibition of progesterone synthesis in placenta by administration of dexamethasone to pregnant rats.

Glucocorticoid receptors have been detected in placenta from several species, including the rat, although the biological function of corticoids is unknown in placenta from the latter species. The present experiments examined the effect of glucocorticoid treatment on placental progesterone biosynthesis from endogenous precursors by incubated basal zone trophoblast and labyrinthine zone of placentas from adrenalectomized-ovariectomized rats at the end of pregnancy. It was found that a higher proportion of synthesized progesterone was retained in the tissue than that released into the incubation medium. Treatment of rats on the 17th-18th day of pregnancy with 10 micrograms/ml of dexamethasone in the drinking saline for 3 days, produced a significant inhibition of progesterone detected in tissue and medium of incubated placental zones. In vitro addition of dexamethasone (10(-4) M) was also effective in reducing progesterone in the placental zone studied (LZ). Serum progesterone of intact rats was in the range of rats near parturition (approx 25 ng/ml) and dropped to almost undetectable levels in rats with adrenalectomy and ovariectomy, with or without dexamethasone treatment, suggesting that in late pregnancy the rat placenta does not contribute significantly to circulating levels of progesterone. This glucocorticoid effect could not be extended to estrogens, as we, in accord with the work of other groups, failed to detect estrogen synthesis in rat placenta. It is suggested that a function for glucocorticoid receptors in rat placenta may be the inhibition of local progesterone production.

Adrenalectomy↗
PubMed1998

Expression of opioid receptors and ligands in pregnant mouse uterus and placenta.

The endogenous opioid system has been implicated in the regulation of hormonal secretion, pain perception, and uterine contractility during pregnancy, but there is only limited information about the cellular location of opioid receptor and opioid peptide gene expression in the pregnant rodent uterus and placenta. In this study, we have used in situ hybridization to identify expression sites of mRNAs encoding the delta (delta), kappa (kappa), and mu ( micro) opioid receptors as well as the endogenous opioid peptide precursors proenkephalin (PENK), prodynorphin (PDYN), and proopiomelanocortin (POMC) in pregnant mouse uterus and placenta. Soon after implantation, all three opioid receptor genes as well as POMC and PENK, but not PDYN, were detected in the uterine environment. Each expressed gene exhibited a distinct expression pattern that was generally retained until late gestation. The delta receptor and POMC were coexpressed in the trophoblast giant cells, which remained the only cells of the placenta/uterus to express these two genes throughout gestation. Cells expressing kappa receptors were absent from the placenta but instead were found in the basal part of the decidualized uterine endometrium. While kappa and micro receptors were transiently expressed in the uterine myometrium (until embryonic day 8.5), substantial levels of PENK were continuously detected in this region until at least embryonic day 18. In addition, complementary expression of the micro receptor and PENK genes in the uterus was detected. Taken together, these results suggest multiple roles for the opioid receptors and opioid peptides in maternal adaptation to pregnancy and in supporting embryo growth.

Animals↗
PubMed1996

Pharmacokinetic and fetal cardiovascular effects of enalaprilat administration to maternal rhesus macaques.

OBJECTIVE: The purpose of this study was to determine the extent of placental transfer of the angiotensin-converting enzyme inhibitor enalaprilat and the effects on maternal and fetal cardiovascular parameters. STUDY DESIGN: Between gestational days 122 and 126 (term 167 days) five rhesus macaques underwent surgery for implantation of maternal and fetal vascular catheters. At least 4 days after surgery maternal and fetal blood pressures and heart rates were recorded for 1 hour. This was followed by a 5-minute maternal venous infusion of saline solution vehicle and recording for an additional hour. Enalaprilat was then infused over 5 minutes through the maternal femoral artery at doses of 0.05, 0.1, or 0.2 mg/kg. Maternal and fetal arterial blood samples were collected for determination of blood gas status and plasma enalaprilat concentrations. RESULTS: Enalaprilat rapidly crossed the placenta, and fetal values for areas under the concentration time curve were 50% to 65% of maternal values across dose groups. Drug was retained in the fetal plasma approximately threefold to fourfold longer than in maternal plasma. Maternal heart rate, blood pressure, arterial Po2 and pH were unchanged after enalaprilat infusion, as were fetal heart rate and blood gases. In contrast, fetal arterial pressure decreased significantly (19% to 23%, p < 0.01) after maternal treatment with 0.1 and 0.2 mg/kg and remained depressed throughout the 6-hour study interval. At 0.05 mg/kg fetal arterial pressure was decreased by 13% from baseline; differences were not significantly different (p > 0.05). CONCLUSIONS: Results from this study indicate that enalaprilat rapidly crosses the primate placenta with a single intravenous administration to the mother, resulting in significant and prolonged reduction of fetal arterial pressure. Because maternal cardiovascular parameters were unaffected, enalaprilat appears to have a direct effect on fetal arterial pressure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2006

Murine embryonic stem cells.

Embryonic stem (ES) cells are derived from preimplantation stage mouse embryos at the time when they have reached the blastocyst stage. It is at this point that the first steps of differentiation take place during mammalian embryonic development. The individual blastomeres now start to organize themselves into three distinct locations, each encompassing a different cell type: outside epithelial cells, trophectoderm; cells at the blastocele surface of the inner cell mass (ICM), the primitive endoderm; and inside cells of the ICM, the primitive ectoderm. ES cells originate from the third population, the primitive ectoderm, which is a transiently existing group of cells in the embryo. Primitive ectoderm cells diminish within a day as the embryo is entering into the next steps of differentiation. ES cells, however, while retaining the property of their origin in terms of developmental potential, also have the ability to self-renew. It is hence important to realize that ES cells do not exist in vivo; they should be regarded simply as tissue culture artifact. Nevertheless, these powerful cells have the potential to differentiate into all the cells of the embryo proper and postnatal animal. Furthermore, they retain the limitation of their origin through their inability to contribute to the trophectoderm lineage (the trophoblast of the placenta) and the lineages of the primitive endoderm, the visceral and parietal endoderm. Due to these unique features, we must admit that even if we regard ES cells as products of in vitro culture and should not compare them to true somatic stem cells found in the adult organism, they certainly offer us a fantastic tool for genetic, developmental, and disease studies.

Animals↗
PubMed1981

The human beta-globin gene and a functional viral thymidine kinase gene in developing mice.

Two foreign cloned genes--one encoding a tissue-specific protein and one encoding a constitutive enzyme--were introduced into mouse eggs by microinjection into a pronucleus shortly after fertilization. They were the adult human genomic beta-globin gene and the thymidine kinase (TK; ATP:thymidine 5'-phosphotransferase, EC 2.7.1.21) gene of herpes simplex virus (HSV), ligated in the pBR322 plasmid. Thirty-three developing mice were autopsied in late fetal life; all appeared normal. Blot hybridization tests revealed that the DNA of as many as five (15%) of the fetuses (from separate litters), and of their corresponding placentas, contained copies of the human beta-globin gene and of the HSV tk gene that had been retained and replicated without significant loss or rearrangement. The estimated total numbers of copies per cell were 3-50 for the donor globin gene and 3-20 for the donor tk. In some of the fetuses, these totals included some copies of molecular weight higher than that of the intact sequence; the additional segments may have arisen through changes such as deletions or duplications. The foreign genes in the five positive fetuses appear to be present in high molecular weight DNA. Assays capable of distinguishing between foreign and native TK indicated that at least one of the fetuses with the HSV tk gene had some TK enzyme of the HSV type and, therefore, at least one gene copy that was being accurately transcribed and translated to produce a functional protein, despite the absence of selective pressure. Thus, pure recombinant genes introduced into mice at the onset of their development can remain intact and be stably incorporated and even expressed. These experiments provide a practical basis for novel investigations of the developmental control of normal gene expression in vivo of the causes and possible cures of genetic diseases.

Animals↗
PubMed2004

Pregnancy after kidney and kidney-pancreas transplantation under tacrolimus: a single center's experience.

BACKGROUND: Chronic renal failure leads to amenorrhea, and successful pregnancy is rare. The aim of the present report is to examine the outcome of pregnancies under tacrolimus after kidney transplantation (KTx) and simultaneous kidney-pancreas transplantation (SPKTx). METHOD: All pregnancies under tacrolimus after KTx or SPKTx from 1993 to April 2002 were retrospectively examined. Renal function and the mother's survival were followed until December 2002. RESULTS: Thirteen mothers after KTx delivered 19 babies, and 2 mothers after SPKTx delivered 3 babies. All mothers survived the pregnancy and retained allograft function. One mother had a stillborn baby from an unrecognized amniotic fluid leak and a small ischemic placenta. The mean gestational period was 34.4 +/- 5.1 weeks. Mean birth weight was 2373 +/- 1001 g. Birth-weight percentile to gestational period was 40 +/- 28. None of the mothers experienced rejection during the pregnancy. Three pregnancies in mothers with KTx experienced toxemia of pregnancy, and one mother with SPKTx developed pre-eclampsia during both pregnancies. Five mothers (6 deliveries, 27.3%) required caesarian section. During the follow-up period, one mother died from a cerebrovascular accident. Another five mothers returned to dialysis 55.6 +/- 32.4 months after the last delivery and 99.4+28.5 months after the last KTx. Both SPKTx mothers have maintained normal renal and pancreatic allograft function 42 and 62 months postdelivery. CONCLUSION: All mothers survived the pregnancy. One baby was stillborn. Forty-one percent of babies were either preterm or premature, and 27% of babies were delivered by caesarean section. Toxemia of pregnancy or pre-eclampsia was observed in 23% of pregnancies postKTx and SPKTx. None of the mothers experienced rejection during their pregnancy.

Birth Weight↗
PubMed1989

Glycosylated human growth hormone variant.

The human growth hormone variant (hGH-V) gene is expressed by the syncytiotrophoblastic layer of the human placenta in two forms: hGH-V mRNA encoding a 22 kD protein, and hGH-V2 mRNA which retains intron 4 and is expected to encode a 26 kD protein. There is a predicted N-linked glycosylation site in hGH-V at amino acid 140 that is absent in both hGH-V2 and in the highly homologous normal pituitary GH (hGH-N). Cell lines transfected with the hGH-N gene secrete 22 kD GH and the 20 kD product of an alternatively spliced mRNA, while cell lines transfected with the hGH-V gene secrete three proteins of 22, 24, and 26 kD. To determine whether any of these hGH-V isoforms are glycosylated, the cell lines were grown in the absence and presence of tunicamycin. In addition, conditioned medium from metabolically labelled hGH-V transfected cells was separately digested with peptide:N-glycosidase F and endoglycosidase H. The 26 and 24 kD bands were both absent from the media after tunicamycin treatment and were both sensitive to peptide:N-glycosidase F treatment. Endoglycosidase H digestion resulted in the selective loss of the 24 kD band. These results indicate that hGH-V is partially modified posttranslationally by N-linked glycosylation in a fibroblastic cell line.

Animals↗
PubMed1975

Evaluation of the three-hour oral glucose tolerance test in detection of significant hyperglycemia and hypoglycemia in pregnancy.

Analysis of 2,000 consecutive patients who had a three-hour 50-gm. oral glucose tolerance test done in the third trimester of pregnancy has shown that the three-hour reading was not necessary for the diagnosis of gestational diabetes. It was found that hyperglycemia and hypoglycemia (95th and 5th percentiles, respectively, for plasma glucose levels) were significantly associated with an increased risk for perinatal mortality. Furthermore, hyperglycemia was associated with an increased incidence of large-for-dates placentas and hypoglycemia with small-for-dates infants and small-for-dates placentas. These associations with hypoglycemia were seen to be greatest when this occurred at the three-hour level, and it was concluded that the three-hour measurement should be retained until the clinical significance of hypoglycemia in pregnancy is fully determined.

Birth Weight↗
PubMedDate not supplied

Localization and distribution of unconjugated steroid hormones in normal placenta at term.

The localization and distribution of unconjugated oestrone, oestradiol-17 beta, oestriol and progesterone were studied in normal term placentae, using subcellular fractionation and indirect immunofluorescence techniques. Radioimmunoassay of these steroids in each subcellular fraction showed that they were detectable mainly in the cytosol fraction. The efficiency of fixatives for retaining steroids in placental tissue during immunohistochemical procedures was studied in order to validate the present experimental techniques. As compared with other fixatives, glutaraldehyde solution produced minimal leakage of steroid hormones from placental tissue. Using an indirect immunofluorescence technique oestrone, oestriol and progesterone were detectable in the cytoplasm of villous syncytiotrophoblast of fixed term placentae.

Adrenal Cortex Hormones↗
PubMed1986

Identification and solubilization of atrial natriuretic factor receptors in human placenta.

Specific high affinity 125I-atrial natriuretic factor binding sites have been identified in human placental membranes. Using the nonionic detergent, Triton X-100, these binding sites were quantitatively solubilized and retained binding activity. In the solubilized preparation, the macromolecular component that binds atrial natriuretic factor is a 160,000 dalton protein as shown by covalently cross-linking it to 125I-atrial natriuretic factor with the bifunctional chemical crosslinker, disuccinimidyl suberate, followed by gel electrophoresis and autoradiography. On Sephadex G-200 gel filtration in the presence of detergent, the hormone-receptor complex elutes in the molecular weight range of 140,000. These observations suggest strongly that a 140- 160,000 dalton protein present in human placental membranes is the receptor for specific recognition of atrial natriuretic factor.

Atrial Natriuretic Factor↗
PubMed1997

Interferon-gamma rescues HLA class Ia cell surface expression in term villous trophoblast cells by inducing synthesis of TAP proteins.

Human placental trophoblast cells that constitute the materno-fetal interface during pregnancy escape maternal alloimmune attack. The different trophoblast cell subpopulations have developed efficient regulatory mechanisms to prevent expression of beta2-microglobulin-associated HLA class Ia molecules at their cell surface. We previously reported the presence of HLA class Ia messages in villous cytotrophoblast cells and in the syncytiotrophoblast differentiated in vitro purified from term placenta. In this study, we found that these transcripts are translated in heavy chain proteins that are endoglycosidase H sensitive and thus retained in the endoplasmic reticulum or cis-Golgi. Moreover, these class Ia heavy chains can be co-immunoprecipitated with the chaperone protein calnexin resident in the endoplasmic reticulum. When these trophoblast cells are treated with interferon (IFN)-gamma, part of the class Ia heavy chains become endoglycosidase H resistant, demonstrating that they have left the endoplasmic reticulum. Furthermore, after such a treatment, these heavy chains are detectable at the cell surface of these trophoblast cells, as assessed by two-color flow cytometry analysis and immunoprecipitation of cell surface biotinylated proteins using the W6/32 anti-HLA class I monoclonal antibody (mAb). IFN-gamma treatment induces a significant enhancement of the transcription of transporters associated with antigen processing (TAP1 and TAP2) rather than an increase of HLA class I or beta2-microglobulin messages. Finally, we demonstrate that an anti-TAP1 mAb co-immunoprecipitates TAP1 proteins and HLA class Ia heavy chains in these IFN-gamma-treated trophoblast cells. Thus, the constitutive absence of HLA class Ia cell surface expression in term villous cytotrophoblast and syncytiotrophoblast is likely to be due to a lack of transporter proteins that participate in the proper assembly of these molecules in the endoplasmic reticulum. Such a defect can be modified upon IFN-gamma treatment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Intracellular polymerization of the serpin plasminogen activator inhibitor type 2.

Plasminogen activator inhibitor type 2 (PAI-2) is synthesized in two molecular forms: an intracellular, nonglycosylated form and an extracellular, glycosylated form. The bitopological distribution of PAI-2 is caused by an inefficient internal secretion signal. In addition, the secretion efficiency of PAI-2 seems to differ, depending on the cell type, differentiation state, and culture conditions. In recombinant cell clones designed for the synthesis of the secreted form of PAI-2, the fraction of secreted PAI-2 decreased with increasing expression levels. Subcellular fractionation of cell clones with higher expression levels revealed that PAI-2 accumulating in the cell was mainly associated with the organelles of the secretory pathway. Electrophoresis under nondenaturating conditions revealed that the PAI-2 retained at higher expression levels was mainly polymerized. Polymers of PAI-2 were also detected in cytosolic extracts prepared from human placenta and phorbol ester-stimulated U 937 cells, indicating that intracellular polymerization of PAI-2 may occur in the cytosols of cells that normally express PAI-2 under physiological conditions. When purified PAI-2 or cellular extracts were incubated at 37 degrees C for 24 h most of the PAI-2 protein was found to polymerize. Polymer formation was prevented by the addition of synthetic peptides with sequences corresponding to residues P2 to P14 in the reactive center loop of PAI-2 and antithrombin. These synthetic peptides also caused dissociation of prepolymerized purified PAI-2 and PAI-2 polymers in cellular extracts. Incubation with unrelated peptides of the same size had no effect on polymer formation or dissociation of preformed polymers, indicating that polymerization of PAI-2 occurs by the loop-sheet mechanism. Taken together, our data suggest that the wild-type form of PAI-2, like some natural pathological genetic variants of alpha1-antitrypsin, antithrombin, and C1 inhibitor readily polymerizes intracellularly and that polymerization may lead to a reduced secretion efficiency.

Amino Acid Sequence↗
PubMed1992

Breastmilk oversupply despite retained placental fragment.

In clients experiencing oversupply, lactation consultants should question more closely the frequency of milk ejection reflexes and whether the mother is experiencing them only during breastfeeding or frequently, even while not nursing. If the mother is still experiencing vaginal bleeding, even if she is producing large quantities of milk, she should be encouraged to talk with her health care provider about having a sonogram in order to rule out the possibility of a retained placental fragment.

Adult↗