Tumor necrosis factor-beta in human pregnancy and labor.

The aims of this study were to determine tumor necrosis factor-beta (TNF-beta) concentration profiles in peripheral venous plasma and amniotic fluid during pregnancy and at the time of labor and to characterise TNF-beta mRNA expression and TNF-beta release from human gestational tissues. In addition, we investigated the expression of TNF-beta binding protein, lymphotoxin-beta (LT-beta), in human gestational tissues. The mean (+/-S.

Release of Type II phospholipase A2 immunoreactivity and phospholipase A2 enzymatic activity from human placenta.

The aim of this study was to determine whether Type II phospholipase A2 (PLA2) is released from late pregnant human placental tissue. Placental explants were incubated in vitro and the release of immunoreactive (ir) Type II PLA2 and PLA2 enzymatic activity into the medium was determined. Both irType II PLA2 and PL2 enzymatic activity accumulated in the incubation medium in a time-dependent manner (P < 0.

Endothelins-1, 2 and 3 are released in vitro from the human bilaterally perfused placenta.

Immunoreactive-endothelin (ir-ET) has previously been detected in human fetal effluents from in vitro perfused placentae. To date however, because of a lack of radio-immunoassay specificity, the ET isoforms in fetal effluents had not been determined, nor had placental maternal effluents been examined for ETs. The aim of this study was to identify the isoforms of ET released into the maternal and fetal circulations of the human in vitro bilaterally perfused placenta.

Placental nitric oxide synthase activity and abnormal umbilical artery flow velocity waveforms.

Objective: To assess the nitric oxide synthase activity in placentas from women with either normal or abnormal Doppler ultrasound umbilical artery flow velocity wave-forms who delivered by elective cesarean.

Methods: This prospective observational study involved 16 women admitted either for elective cesarean for standard obstetric indications (with normal umbilical artery Doppler waveform studies, n = 8) or with evidence of fetal or maternal complications of pregnancy (with abnormal umbilical artery Doppler studies, n = 8). Placental tissue was collected and frozen in liquid nitrogen immediately upon delivery.

Localization of type II phospholipase A2 messenger RNA and immunoactivity in human placenta and fetal membranes.

Although Type II phospholipase A2 (PLA2) immunoactivity has been identified in homogenates of human placenta and fetal membranes, there is a paucity of information concerning the sites of synthesis of this secreted PLA2 isozyme. The aim of this study, therefore, was to establish the cellular localization of Type II PLA2 messenger RNA (mRNA) in human term placental and fetal membranes by in situ hybridization. In addition, the co-localization of immunoreactive Type II PLA2 in gestational tissues was determined, and the effect of labour status and pre-eclampsia on immunolabelling intensity were established.

Labour-associated increase in interleukin-1 alpha release in vitro by human gestational tissues.

The aims of this study were to investigate the concentration and release of interleukin-1 alpha (IL-1 alpha) at the time of human term labour, and to study the regulation of IL-1 alpha release from human gestational tissue explants by bacterial endotoxin. Immunoreactive IL-1 alpha concentrations in maternal plasma, amniotic fluid and conditioned media from human amniotic fluid and conditioned media from human amniotic, choriodecidual and placental explants were quantified before and after spontaneous term labour-onset and delivery. Furthermore, the effects of a bacterial endotoxin, lipopolysaccharide (LPS), on the release of IL-1 alpha from human gestational tissue explants over a time course of 24 h (n = 3) and LPS concentrations ranging from 10-10(7) pg/ml (n = 3) were investigated.

Differential release of interleukin-6 from human gestational tissues in association with labour and in vitro endotoxin treatment.

In this study, we quantified interleukin-6 (IL-6) concentrations in amniotic fluid at term and preterm labour, and determined the gestational tissue source of IL-6. In addition, aspects of the regulatory mechanisms involved in IL-6 release at the time of term labour and in response to bacterial endotoxin, lipopolysaccharide (LPS), have been established. IL-6 concentrations were 2-fold higher in amniotic fluid collected at term compared with preterm gestation, with an additional 2-fold increase in association with term labour.

Alpha-atrial natriuretic peptide-induced attenuation of vasoconstriction in the fetal circulation of the human isolated perfused placenta.

In order to examine the effect of alpha-ANP on fetal placental vascular tone, single placental lobules were bilaterally perfused and fetal inflow pressure recorded. The placental vasculature was sub-maximally pre-constricted by infusion of the nitric oxide synthase inhibitor N omega-nitro-L-arginine (NOLA) or the thromboxane A2-mimetic U46619. In the presence of continuous infusion of 59.

HLA-G deletion polymorphism and pre-eclampsia/eclampsia.

Objective: To investigate a HLA-G deletion polymorphism in pre-eclamptic pedigrees and the general population.

Design: A population association study of HLA-G genotypes from pre-eclamptic/eclamptic patients and control groups.

Setting: Analyses undertaken in the School of Biological Sciences, Macquarie University.

Fetal fibronectin in the cervicovaginal fluid of women with threatened preterm labour as a predictor of delivery before 34 weeks' gestation.

Fetal fibronectin (fFN) is an extracellular matrix protein found at the junction between fetal and maternal tissue. It has been hypothesized that fFN is released into cervicovaginal fluid prior to the onset of preterm labour and during episodes of threatened preterm labour (TPL). In the present study fFN was present in the cervicovaginal fluid of 31% (11/36) of patients with TPL.

Aspirin and prevention of preeclampsia. Position statement of the use of low-dose aspirin in pregnancy by the Australasian Society for the Study of Hypertension in Pregnancy.

1. A heterogeneous group of randomized trials have been conducted using low-dose aspirin to prevent preeclampsia. The results do not support widespread use of low-dose aspirin to prevent preeclampsia.

Effect of asymmetric dimethyl arginine on nitric oxide synthase activity in normal and pre-eclamptic placentae.

An endogenous inhibitor of nitric oxide synthase (NOS), NG,NG dimethylarginine (asymmetric dimethylarginine, ADMA), which is present in human plasma and urine, has been reported to be elevated in the plasma of women with pre-eclampsia. As ADMA inhibition may contribute to reduced placental NOS activity observed in pre-eclampsia, the aim of this study was to compare the effects of ADMA on placental NOS activity from pre-eclamptic and normal pregnancies (gestational ages 38.4 +/- 0.

Parathyroid hormone-related protein (PTHrP) concentrations in human amniotic fluid during gestation and at the time of labour.

To establish the changes associated with gestational age and labour status in parathyroid hormone-related protein (PTHrP) concentrations in the amniotic fluid, human amniotic fluid was collected from non-labouring and labouring women at < 37 weeks of gestation (preterm) and at term (> or = 37 weeks). PTHrP was assayed by a specific N-terminal radioimmunoassay. PTHrP concentrations in amniotic fluid obtained from non-labouring women were significantly lower at preterm (15-36 weeks; 14.

Human placental and fetal membrane nitric oxide synthase activity before, during and after labour at term.

The aim of this study was to determine whether any labour-associated changes in nitric oxide synthase (NOS) activity occur in human placenta and fetal membranes. NOS activity in amnion, choriodecidua, and placenta obtained from women before (at Caesarean section, not in labour), during (at Caesarean section, in labour) and after (spontaneous onset labour, normal vaginal delivery) labour was assessed by measuring conversion of radio-labelled L-arginine to L-citrulline. NOS activity, as judged by its inhibition by the specific NOS inhibitor N omega-nitro-L-arginine, was present in placental and amnionic tissues, but not in choriodecidual tissue specimens.

Regulation of human placental fetal vessel tone: role of nitric oxide.

Factors affecting fetal vessel resistance have been studied in vitro in bilaterally perfused lobules of human placentae. Potent and efficacious constrictors in this preparation (in order of potency) include endothelin-1 > the thromboxane mimetic U46619 > endothelin-3 > prostaglandin F2 alpha. Inhibitors of eicosanoid synthesis did not affect fetal vessel basal perfusion pressure, nor did they potentiate the effects of the vasoconstrictor U46619.

Calcium dependence of alpha-aminoisobutyric acid transfer in human bilaterally perfused placental lobules.

Human isolated bilaterally perfused placental lobules were employed to study the Ca++ dependence of materno-fetal transfer of the non-metabolisable amino acid, alpha-aminoisobutyric acid (AIB). Bilateral perfusion with Ca(++)-free Krebs' solution containing 2 mmol/l EDTA for 60 min resulted in a significant reduction in materno-fetal AIB transfer compared to controls perfused with normal Krebs' solution. However, bilateral perfusion with Krebs' solution containing: 2.

Prostaglandin G/H synthase-1 messenger RNA relative abundance in human amnion, choriodecidua and placenta before, during and after spontaneous-onset labour at term.

The aim of this study was to determine the relative abundance of prostaglandin G/H synthase-1 (PGHS-1) mRNA in human amnion, choriodecidua and placenta obtained before (n = 5), during (n = 5) and after spontaneous-onset labour and delivery at term (n = 5). PGHS-1 mRNA relative abundance was not affected by labour status (p > 0.1) nor differently expressed between gestational tissues (p > 0.

Tumour necrosis factor alpha during human pregnancy and labour: maternal plasma and amniotic fluid concentrations and release from intrauterine tissues.

The aims of this study were: to quantify immunoreactive tumour necrosis factor alpha (TNF-alpha) concentrations in maternal plasma and amniotic fluid obtained from women during pregnancy and labour, both at term and preterm; and to establish the effects of bacterial endotoxin and cytokines on the in vitro release of TNF-alpha from intrauterine tissues. Maternal plasma TNF-alpha concentrations did not change during pregnancy (457.2 +/- 102.

Effects of lipopolysaccharide on human placental prostaglandin F2 alpha production in vitro.

The effect of bacterial endotoxin (lipopolysaccharide, LPS), on the release of prostaglandin F2 alpha (PGF2 alpha) from human placental explants was investigated. Both LPS and calcium ionophore A23187 stimulated PGF2 alpha release (p < 0.05).

Bacterial endotoxin increases type II phospholipase A2 immunoreactive content and phospholipase A2 enzymatic activity in human choriodecidua.

The aim of this study was to establish the effect of bacterial endotoxin lipopolysaccharide (LPS) on type II phospholipase A2 (PLA2) content and in vitro net PLA2 enzymatic activity in human choriodecidua. More particularly, the objective was to ascertain whether an increase in type II PLA2 tissue content and PLA2 enzymatic activity is associated with the previously documented stimulatory effect of LPS on prostaglandin E2 (PGE2) release from choriodecidua. Choriodecidua explants were incubated in RPMI 1640 (control) or RPMI 1640 containing LPS (0.

Type II phospholipase A2 in human gestational tissues: extractable immuno- and enzymatic activity in fetal membranes.

In this study, we have established the presence of immunoreactive (ir) Type II PLA2 in human amnion and choriodecidua obtained from women at term prior to the onset of labour. The content of irType II PLA2 present in 1 M NaCl extracts of choriodecidua and amnion averaged 3.5 +/- 3.

Effect of the choline acetyltransferase inhibitor (2-benzoylethyl)-trimethylammonium iodide (BETA) on human placental prostaglandin release and phospholipase A2 activity.

We investigated the effect of an inhibitor of acetylcholine (ACh) synthesis, (2-benzoylethyl)trimethylammonium iodide (BETA), on prostaglandin (PG)E2 and PGF2 alpha release from incubated placental explants in the presence or absence of ACh or arachidonic acid (AA). BETA alone (100 microM) significantly reduced both PGE2 and PGF2 alpha release. However, this inhibitory effect of BETA was not reversed in the presence of ACh (10 microM to 1 mM).

A randomized, double-blind, placebo-controlled trial of the safety of vaginal recombinant human relaxin for cervical ripening.

Objective: To assess the safety of vaginal recombinant human relaxin in pregnant women treated before the induction of labor and to collect preliminary data on the efficacy of recombinant human relaxin in promoting cervical ripening.

Methods: In a multi-center, randomized, double-blind placebo-controlled trial, 40 women were studied before induction of labor because of post-dates. The women were randomized to receive either 1.