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PubMed2000

An unusual member of the human growth hormone/placental lactogen (GH/PL) family, the testicular alternative splicing variant hPL-A2: recombinant expression revealed a membrane-associated growth factor molecule.

The human growth hormone/placental lactogen (GH/PL) gene cluster consists of five highly-related genes (GH-N, GH-V, PL-L, PL-A, PL-B). This evolutionarily young gene cluster codes for an array of mRNAs and proteins, such as the major 22 k forms (hGH-N/V, identical PL-A and B), 20 k and 17.5 k hGH-N and the recently described 25 k hGH-Delta4, a presumably chimeric molecule. In addition, two longer alternatively spliced, (intron D retaining) mRNAs isoforms, termed PL-A2 and GH-V2, have been described in placenta and testis. To elucidate the role of hPL-A2 in male reproduction and pregnancy, testicular PL-A2 cDNA was cloned in a complementary overlapping 2-way RT-PCR approach to analyze translation, localization and structure/function of this unusual member of the GH/PL growth factor family. Analysis of insect mRNA revealed that intron D-retaining PL-A2 cDNA was expressed without splicing in the baculovirus expression system. Thus, PL-A2 mRNA does not represent a nuclear intermediate splicing product simply co-isolated with the mature RNA, but is a stable mRNA isoform generated by placental/testis-specific splicing factors. Recombinant protein was present in whole cell extracts, and no secreted protein was detected in the supernatant. Immunologically, the N-terminus of the 230 amino acid protein is similar to 22 k hPL-A/B, as determined by hPL-specific monoclonal antibodies. In contrast, the C-terminus shares a hydrophobic region presumably responsible for membrane insertion. By the use of confocal microscopy recombinant hPL-A2 was localized in the cell membrane. Thus, hPL-A2 might exert its function by modulating GH/PL actions or act as an independent growth-regulatory molecule itself and its functions in male reproduction and embryonic development remain to be investigated.

Aged↗
PubMed1985

Strontium-85 in the fetuses of pregnant rats and mice.

Pregnant SPF Wistar rats and ICR/Swiss albino mice were injected in the tail vein with 85SrCl2 with 0.05 mM inactive carrier (SrCl2) given in volumes of 0.1 ml. The activity in the injected volume was about 14 MBq per kg of rat and 13 MBq per kg of mouse. The animals were injected at 2 or 13 days of gestation. The activity retained by the fetuses was quantitatively determined at three stages of the fetal intrauterine development: in rats at 14, 16 and 21 days of gestation, in mice at 14, 16 and 20 days of gestation. The activity of fetuses and/or placentas with fetal membranes was measured using a TESLA automatic gamma counter. Results indicate that fetuses of mice retained a significantly (P less than 0.01) greater percent of strontium activity than fetuses of rats. The highest specific activities (the percentage of total activity retained per gram of fetal tissue) were found in the late pregnancy period (at 21 days of gestation in rats and 20 days of gestation in mice) in animals that were injected with the radionuclide at 13 days of gestation.

Animals↗
PubMed2004

[Intractable postpartum haemorrhages: where is the place of vascular ligations, emergency peripartum hysterectomy or arterial embolization?].

OBJECTIVE: Update of knowledge on the various methods of management of intractable postpartum haemorrhage. METHOD: PubMed, MEDLINE were the electronic sources, in English and French languages, used for data retrieval. Uterine atony and abnormal placental insertions (placenta praevia or accreta) are the major causes of primary postpartum haemorrhages. To preserve fertility, we dispose of angiographic selective embolization or surgical vascular ligations. Embolization is a non-invasive method practicable by simple catheterization under local anesthesia. Vascular ligations of the uterine vessels or internal iliac arteries require mostly laparotomy. New and easier surgical methods, such as uterine compression or hemostatic suturing techniques have been described for which we lack experience. RESULTS: For uterine atony, the success rate of arterial embolization and uterine artery ligations is close to 100%. Ligation of internal iliac arteries is a little less effective and technically more difficult to carry out. It remains interesting in obstetrical traumatic hurts, which do not concern the uterus. If bleeding from the lower segment occurs during caesarean section, low uterine artery ligatures are necessary. These methods are all the more effective than they are prematurely implemented before the rise of major coagulopathy. In this case, uterine devascularization has also to be applied to ovarian vessels. With placenta accreta, accreta portion of the placenta can be left in place and arterial embolization or vascular ligations can be done. Nevertheless the main cause of failure with conservative treatments is placenta accreta. CONCLUSION: The simplest and the least morbid methods must be retained. After vaginal birth, arterial embolization can be done, if there is no maternal haemodynamic disorder nor interventional vascular radiology unit nearby. During caesarean section, progressive uterine artery ligation can be done adapted to the bleeding cause. In case of failure of a conservative treatment, it would be dangerous to multiply techniques. Emergency peripartum then should remain the choice procedure.

Arteries↗
PubMed1997

Conformational studies of mono- and bicyclic parathyroid hormone-related protein-derived agonists.

Parathyroid hormone-related protein (PTHrP) is expressed in a wide variety of cells where it acts as an autocrine and/or paracrine factor involved in regulation of cellular growth, differentiation, and embryonic development. It may also play a physiological endocrine role in calcium transport across the placenta or during lactation. The N-terminal portion, PTHrP-(1-34), retains all the calciotropic parathyroid hormone-like activity and is a lead structure for the design of novel, bone anabolic agents for the treatment of bone disorders such as osteoporosis. To characterize the putative bioactive conformation, we have carried out a detailed structural analysis of a series of three conformationally constrained PTHrP-(1-34)-based mono- and bicyclic lactam-containing biologically active analogs: (III) The conformational properties were studied by circular dichroisim, nuclear magnetic resonance spectroscopy, distance geometry calculations, and molecular dynamic simulations in water/trifluoroethanol (TFE) mixtures. The helical content in water of both monocyclic analogs I and II is approximately 22%; that of the bicyclic analog III is approximately 40%. In 30% TFE, all analogs reached a maximal helical content of 80%, corresponding to 26 or 27 residues out of 34 in a helical conformation. High-resolution structures obtained with 50:50 TFE/water revealed that all three analogs display two helical domains and a hinge region around Gly12-Lys13. The highly potent mono- and bicyclic agonists I and III display a second hinge around Arg19-Arg20 which is shifted to Ser14-Asp17 in the weakly potent monocyclic agonist II. We suggest that the presence and localization of discrete hinges in the sequence together with the high propensity for helicity of the C-terminal sequence and the enhancement of helical nucleation at the N-terminal sequence are essential for generating a PTH/PTHrP receptor-compatible bioactive conformation.

Circular Dichroism↗
PubMed2001

Maternal-fetal transfer of saquinavir studied in the ex vivo placental perfusion model.

OBJECTIVE: This study was undertaken to determine the placental transfer of the human immunodeficiency virus protease inhibitor saquinavir. STUDY DESIGN: An ex vivo perfused human placental cotyledon model was used. Ten placental perfusion studies were performed, with concentrations of saquinavir in the maternal compartment ranging from 322 to 2197 ng/mL (within reference therapeutic ranges). Drug concentrations were determined by high-performance liquid chromatography. RESULTS: The mean (+/- SD) fetal transfer rate of saquinavir was 1.8% +/- 1.6%, and the mean (+/- SD) clearance index was 0.05 +/- 0.05. A mean (+/- SD) of 1.6% +/- 3.1% of the perfused saquinavir was retained by the cotyledon. The small amount of saquinavir that crossed the placenta corresponded to the fraction not bound to human serum albumin. CONCLUSION: The low rate of placental transfer of saquinavir suggests that use of this antiretroviral drug by pregnant women may not lead to significant exposure of the fetus.

Female↗
PubMed1983

Epidermal growth factor-like transforming growth factor. II. Interaction with epidermal growth factor receptors in human placenta membranes and A431 cells.

A 125I-labeled derivative of rat epidermal growth factor-like transforming growth factor (125I-eTGF) that retains the chemical and biological properties of native eTGF has been prepared to characterize the interaction of eTGF with epidermal growth factor (EGF) membrane receptors. Binding of 125I-eTGF and 125I-labeled mouse EGF (125I-EGF) to membrane preparations from human placenta and the A431 human epidermoid carcinoma cell line was competed for to the same extent and with the same potency by either unlabeled eTGF or EGF. Components of placenta membranes and A431 membranes (145-170 kDa) were the major species affinity-labeled by cross-linking with membrane-bound 125I-eTGF or 125I-EGF. Affinity labeling of these receptor species was fully inhibited by both native eTGF and native EGF when present in excess during incubation of membranes with 125I-eTGF or 125I-EGF. The binding affinity and capacity of receptors in A431 membranes and placenta membranes were strikingly similar for eTGF and EGF. However, binding of 125I-eTGF to membrane receptors was highly sensitive to pH, being optimal only within the pH 8.0-8.5 range whereas EGF binding was optimal at pH 7.0-9.0. eTGF binding and EGF binding were modified in parallel by exposure of placental membranes to phytohemagglutinin, concanavalin A, or wheat germ agglutinin. Prolonged exposure of A431 cells to eTGF or EGF induced the same extent of down-regulation of both eTGF binding and EGF binding. eTGF-induced down-regulation of receptors in A431 cells followed the same kinetics as EGF-induced receptor down-regulation. The data indicate that despite the limited sequence homology between eTGF and EGF, these two ligands exhibit a remarkably similar mode of interaction with a common eTGF/EGF membrane receptor type.

Carcinoma, Squamous Cell↗
PubMed1989

Identification and characterization of receptors for granulocyte colony-stimulating factor on human placenta and trophoblastic cells.

Since radioiodination of human granulocyte colony-stimulating factor (G-CSF) is difficult, we synthesized a mutein of human G-CSF that retains full biological activity and receptor-binding capacity for at least 2 weeks after radioiodination. Receptors for human G-CSF were characterized in the plasma membrane fraction from the human term placenta (human placental membranes) and trophoblastic cells by using the 125I-labeled mutein of human G-CSF (KW-2228). The specific binding of 125I-labeled KW-2228 to placental membranes was pH-dependent, with maximal specific binding at pH 7.8; it increased linearly with protein to 3.7 mg of protein per ml and was both time- and temperature-dependent, with maximal binding at 4 degrees C after a 24-hr incubation. When we examined the ability of hematopoietic growth factors to inhibit 125I-labeled KW-2228 binding, we found that KW-2228 and intact human G-CSF inhibited 125I-labeled KW-2228 binding, whereas erythropoietin or granulocyte-macrophage colony-stimulating factor did not. Scatchard analysis revealed a single receptor type with a Bmax of 210 fmol/mg of protein and a Kd of 480 pM. The human G-CSF receptors on human placental membranes were shown to consist of two molecular species of 150 kDa and 120 kDa that could be specifically cross-linked to 125I-labeled KW-2228. Human trophoblastic cells, T3M-3, also possessed a single receptor for G-CSF with a Bmax of 533 receptors per cell and a Kd of 390 pM. Thus we have identified the receptor for human G-CSF on human placental membranes and trophoblastic cells, and the presence of this receptor in these membranes suggests that human G-CSF plays some role in the feto-placental unit during human development.

Binding, Competitive↗
PubMed1984

Growth and function of human placenta and amnion grafted to nude mice. A preliminary communication.

Normal human placenta and amnion from the 20th week of pregnancy were transplanted into nude mice. The transplants retained the histological and immunohistochemical picture of the original tissue and maintained synthesis of human chorionic gonadotropin (hCG), pregnancy-specific beta 1-glycoprotein (SP1), GnRH and placental proteins PP5, PP11 and PP12 for 5 weeks. This experimental model has a wide potential application for studies on placental protein synthesis and the hormonal influence of human placenta on other simultaneously transplanted human tissues.

Amnion↗
PubMed2006

The extent and variability of effects of culture conditions on the secretion of human chorionic gonadotrophin and interleukin-6 by human, term placental explants in culture.

Culture of explants derived from third trimester human placenta is used in a range of contexts as an experimental model that retains tissue architecture. This study aimed to explore the variability between, and within, individuals of secretion by explants of human chorionic gonadotrophin (hCG) and interleukin-6 (IL-6). Standard culture medium contained hydrocortisone, insulin, retinoic acid and serum. Under these conditions explants displayed significant differences in the time-course and extent of hCG secretion. Peak hCG secretion varied between 1.19 and 242 mIU/mg protein/h (coefficient of variation (CV) = 111%) and could occur between days 4 and 7 of culture. hCG secretion was more variable if explant protein was < 400 microg. Unadjusted day 7 hCG secretion showed marked variation: intra-placental CV = 15%, inter-placental CV = 86%. When day 7 hCG secretion was standardised by day 6 secretion, intra-placental CV was 6.9%, inter-placental CV was 4.0%. When this standardisation was applied, hCG secretion during day 7 of culture was not affected by removal of hydrocortisone, insulin or serum from the medium or by the addition of tumour necrosis factor-alpha (TNF-alpha). The secretion of IL-6 during day 7 of culture (standardised by taking natural logarithms) was increased markedly by the addition of TNF-alpha but unaltered by removing hydrocortisone, insulin or serum. Thus, we have shown that although variable, secretion by placental explants can be used to investigate how placental tissue adapts to different culture conditions. However, explants of the same protein content may have markedly different secretory properties.

Chorionic Gonadotropin↗
PubMed2003

Sonographic imaging of maternal complications of pregnancy.

OBJECTIVE: To show the role of diagnostic sonography in delineating pathologic conditions occurring during and immediately after pregnancy. METHODS: Cases illustrative of a broad range of pathologic conditions were collected primarily from personal experience in a busy ultrasound clinic serving high-and low-risk pregnancies over the past 15 years, with supplemental cases drawn from departmental teaching files. Sonography was the primary diagnostic tool, with confirmation obtained from other imaging modalities in select instances. RESULTS: Cases were organized on an anatomic and time-of-onset basis. For conditions occurring during pregnancy, the following anatomic areas are considered: the liver and biliary tree, urinary tract, bowel, ovary, and uterus and placenta. For postpartum complications, the following conditions are discussed: subfascial and bladder flap hematomas, retained products of conception, and ovarian vein thrombophlebitis. Although the main imaging modality in these conditions was sonography, correlation with computed tomography and magnetic resonance imaging was also made in several cases. CONCLUSIONS: A broad variety of conditions can affect the pregnant patient, both during and immediately after pregnancy. Sonography can show many of these disease processes, with computed tomography and magnetic resonance imaging useful selectively as supplementary tools.

Biliary Tract Diseases↗
PubMed2002

Reduction in the occurrence of uterine rupture in Central India.

This study was carried out in the Department of Obstetrics and Gynaecology of the Mahatma Gandhi Institute of Medical Sciences, Sevagram in Central India. In the 12 years between 1989 and 2000 a total of 16 cases of ruptured uterus were managed, the incidence of rupture of the pregnant uterus being 0.62 per 1000 births. One-quarter of the cases occurred between 1983 and 1988. No teenager or elderly woman (over 40) or grandmultipara sustained a uterine rupture. Four women had a rupture of a previous scar. In five rupture had occurred in association with malpresentations, one was a case of hydrocephalus, two had a morbidly adherent placenta praevia and four had a normal presentation, with lack of progress in labour. Two of these 16 women had twins. One had come with a retained second twin with transverse lie and the other was a booked case with multiple problems, including a previous caesarean section, present twin pregnancy and placenta praevia accreta and she died. This was the only maternal death. Perinatal mortality was 77.77% compared to 5.88% maternal and 100% perinatal mortality in the cases reported previously between 83 and 88, from the same institution. Overall, there is some improvement in perinatal survival and one-quarter incidence of rupture of the pregnant uterus.

Adult↗
PubMed1984

Changes in the fine structure of rat visceral yolk-sac placenta during prolonged pregnancy.

Visceral yolk-sac membranes were obtained surgically from viable rat fetuses which had been retained experimentally in utero in lactating animals for as long as 3 days beyond delivery of their littermates. They were examined with the electron microscope. The fine structure of the yolk-sac placental membrane (i.e., the tissues separating vitelline capillary lumina from the uterine cavity) remained unimpaired during the delay period. Progressive changes included a decrease in the height of the endodermal epithelium, but a thickening of the basement membrane underlying it by repeated replication of the subepithelial basal lamina and an increase in collagen fiber content in the reticular lamina. Transcytosis across the endothelium of the capillaries of the peripheral vitelline circulation remained unchanged throughout the delay period; endocytosis of materials, presumably maternal serum proteins, from the uterine cavity into the apices of the endodermal epithelium, however, decreased with time. At the oldest stage (26 days post-coitum) most endocytosed materials had been stored for hydrolysis in large subapical vacuoles which were identified as secondary lysosomes; and evidence of uptake from the uterine lumen was essentially absent. Accordingly, placental transport of protein by the visceral yolk sac of the rat can be regarded as a perinatal process. The action of an elaborately developed and well-preserved Golgi apparatus in both cellular mechanisms, viz., digestion of maternal proteins and protein transfer, was inferred.

Animals↗
PubMed1991

Neuroendocrinology of the hypothalamo-pituitary-adrenal axis in pregnancy and the puerperium.

Plasma cortisol, adrenocorticotrophic hormone (ACTH), beta-endorphin and corticotrophin releasing hormone or factor (CRF) all rise progressively as pregnancy advances, and fall postnatally. The placenta produces large amounts of CRF in the third trimester and this is released into the maternal circulation. Present evidence suggests that it stimulates the maternal pituitary to produce ACTH while desensitizing the maternal pituitary to further stimulation with CRF. Maternal control of ACTH production is retained, allowing a persistent response to stress and a diurnal rhythm, perhaps through the secretion of vasopressin. The placenta also produces pro-opiomelanocortin peptides; however, the nature of the fragments produced from the precursor differs from that formed in the anterior pituitary of the mother and the role of these fragments in the control of maternal adrenal function is unclear. These changes in the hypothalamo-pituitary-adrenal axis during pregnancy are associated with loss of the normal suppression of cortisol by dexamethasone and elevated basal levels of cortisol with preservation of a diurnal rhythm, features also found in some patients with endogenous depression. Several studies have suggested a relationship between alterations in maternal concentrations of cortisol and beta-endorphin and the development of postnatal mood disturbances.

Adrenal Glands↗
PubMed1994

Anti-oncogene product p53 binds DNA helicase.

An oncogene product, p53, interacts with a simian virus 40-encoded T-antigen, which is an initiation protein for the viral DNA replication and also works as DNA helicase during elongation. Here we examine the interaction of p53 with cellular DNA helicase. A recombinant human wild type p53 fused with glutathione S-transferase was immobilized on glutathione-agarose as a ligand for affinity column. Hela cell extract was applied to the p53 column and the adsorbed proteins were eluted with buffers containing salt, 50% ethylene glycol, and glutathione. The ethylene glycol fraction contained a number of p53 binding proteins, and this fraction showed a DNA helicase activity measured by the displacement of DNA fragment from partially duplexed M13 DNA. The DNA helicase translocated in a 5'-to-3' direction on the single-stranded DNA using ATP as an energy source. The glutathione fraction that contained the p53 glutathione S-transferase fused protein also showed the same activity. The corresponding fractions from a control column carrying glutathione S-transferase showed only a trace amount of activity of DNA helicase. Therefore, the binding may be specific. Furthermore, an anti-p53 antibody column retained a p53-DNA helicase complex when the crude extracts of human placenta and of osteosarcoma cells were applied. These results indicate that p53 physically interacts with DNA helicase in vitro as well as in vivo.

Chromatography, Affinity↗
PubMed2004

Evidence for placental transfer of lipids during gestation in the viviparous lizard, Pseudemoia entrecasteauxii.

During gestation in the viviparous lizard Pseudemoia entrecasteauxii, the fetus obtains nutrients from two sources: uptake of yolk components from the retained egg (lecithotrophy) and transfer of nutrients from the maternal circulation via the placenta (placentotrophy). Although net placentotrophy in this species is indicated by the observation that the neonate contains 1.7 times more dry matter than the egg, the placental transfer of lipid has not been previously demonstrated. Lipid analysis was performed on newly ovulated eggs and on neonates. The weight of total lipid per neonate (8.2+/-0.5 mg) is significantly (P=0.049) greater than that in the egg (6.8+/-0.4 mg), indicating that the placenta must contribute some lipid to the fetus. On the assumption that 50% of the lipid delivered to the fetus from either source is oxidized for energy, it is calculated that the placenta accounts for 58.5% of the fetal lipid requirements, with the remaining 41.5% being derived from the egg. The fatty acid compositions of the triacylglycerol and phospholipid recovered in the neonatal tissue differ substantially from those of the egg. In particular, the proportions of 18:2n-6 and 18:3n-3 are far lower in the neonatal lipids compared with the egg lipids. On the other hand, the proportion of 22:6n-3 in the phospholipid of the neonate is six times higher than in the phospholipid of the egg. The absolute amount (mg) of 22:6n-3 recovered in the total lipid of the neonate is 3.8 times greater than the amount initially present in the egg. By comparison, the amount of total fatty acid in neonatal lipid is 1.2 times greater than the amount in the egg. Thus, there is a preferential use of 22:6n-3 for tissue phospholipid synthesis during development. We conclude that there is net transfer of fatty acids across the placenta to the fetus of P. entrecasteauxii and a high degree of selectivity in the use of the various fatty acids for fetal tissue lipid synthesis.

Animals↗
PubMed1991

Importance of the placenta and cord in the defense of neurologically impaired infant claims.

Verdicts in favor of the defense were delivered in all 12 cases tried to a conclusion in which the placenta and/or cord was available for examination and was found to be abnormal or diseased and in which testimony was provided by a placental pathologist. The St Paul (Minn) Fire and Marine Insurance Company recommends that placenta/cord specimens be retained in cases where the mother is at high risk, the fetus/newborn has certain high-risk characteristics, and/or the placenta appears to be grossly abnormal. If a claim is made against the health care providers, the specimens can subsequently be examined by a placental specialist for possible trial testimony. The placenta may well be the key to a solid defense for these cases in the courtroom.

Birth Injuries↗
PubMed1992

65zinc metabolism is altered during diabetic pregnancy in rats.

To assess further diabetes-induced alterations in gestational Zn metabolism we examined the uptake/retention and distribution of 65Zn during pregnancy. Control and streptozotocin-induced diabetic rats, with and without insulin treatment, were gavaged with 65Zn on gestational d 12 or 18. Six hours post-intubation, untreated diabetic dams at d 12 of gestation had a lower percentage of retained 65Zn in bone, plasma, erythrocytes, pancreas and spleen than did controls. Retention of 65Zn in amniotic fluid and sacs and in embryos was similar among groups. Untreated diabetic dams at d 18 of gestation had a higher percentage of retained 65Zn in liver, intestine and urine, and most notably a lower percentage in amniotic fluid, placenta, fetus and fetal liver. Lower percentages of 65Zn were found in bone, muscle, plasma, erythrocytes, lung, spleen, heart, pancreas and uterus of diabetic dams compared with controls. HPLC fractionation of samples from maternal livers showed a higher percentage of Zn, Cu and 65Zn associated with the metallothionein peak in samples from untreated diabetic dams compared with other groups, whereas the percentages of Zn, Cu and 65Zn per fraction in fetal liver were similar. The marked decrease in retained 65Zn in products of conception at d 18 suggests either decreased placental transport or altered maternal and/or fetal Zn-binding ligands. Insulin treatment significantly reversed the streptozotocin diabetes-induced derangements in maternal and fetal Zn metabolism.

Animals↗