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C J Lockwood

Publications and source records attributed to C J Lockwood.

At least 91 records · Page 5Linked to original sources
PubMed1995

Biological mechanisms underlying the clinical effects of RU 486: modulation of cultured endometrial stromal cell plasminogen activator and plasminogen activator inhibitor expression.

The abortifacient and menstrual effects of the potent antiprogestin, RU 486, are associated with both endometrial hemorrhage and extracellular matrix (ECM) degradation. Such processes reflect reduced perivascular decidual cell hemostatic and increased ECM-degrading protease activity. Therefore, we assessed the effects of RU 486 administration on the expression of immunoreactive (ir) endometrial stromal cell urokinase-type (uPA) and tissue-type (tPA) plasminogen activator and their activities as well as levels of ir type 1 plasminogen activator inhibitor (PAI-1) using a well characterized in vitro model of decidualization. Thus, confluent stromal cell cultures were exposed to vehicle control, 10(-8) mol/L estradiol (E2), 10(-7)-10(-8) mol/L medroxyprogesterone acetate (MPA), E2 plus MPA, or 10(-6)-10(-7) mol/L RU 486 alone or in combination with MPA or E2 plus MPA for 3-4 days. Compared to the vehicle control, E2 and RU 486 used alone had no effect on levels of ir PAI-1, uPA, or tPA or on PA activity in the conditioned medium. In contrast, MPA and E2 plus MPA decreased ir uPA and tPA levels and their corresponding activities, whereas MPA increased, and E2 plus MPA further increased ir PAI-1 release. These effects of progestin were blocked by a log higher concentration of RU 486. Similar results were obtained for steady state PAI-1 messenger ribonucleic acid levels. To determine if RU 486 reversed progestin-inhibited stromal cell uPA and tPA release and progestin-enhanced PAI-1 expression, confluent cultures were exposed to 10(-8) mol/L E2 plus 10(-7) mol/L MPA for 10 days, washed, and reexposed to E2 plus MPA, steroid-free medium, or RU 486 for 3-5 or 9-11 days. Compared with cultures maintained in E2 plus MPA for 3-5 days, withdrawal to a steroid-free medium failed to affect stromal cell ir PAI-1, uPA, or tPA levels. In contrast, exposure to RU 486 for 3-5 days increased ir uPA and tPA levels 5- to 8-fold (P < 0.02) while reducing PAI-1 levels by 85% (P < 0.04). By 9-11 days of treatment, steroid withdrawal and RU 486 exerted similar effects on ir PAI-1, tPA, and uPA levels. Comparable results were obtained for PAI-1, uPA, and tPA steady state messenger ribonucleic acid levels. These findings indicate that RU 486 blocks and reverses progestin-inhibited PA expression, suggesting a mechanism for RU 486-induced endometrial hemorrhage and ECM dissolution.

Cells, Cultured↗
PubMed1995

Reduction of extracellular matrix protein expression in human amnion epithelial cells by glucocorticoids: a potential role in preterm rupture of the fetal membranes.

Low levels of expression of extracellular matrix (ECM) proteins in chorioamniotic membranes is a characteristic of prematurely ruptured membranes, a condition associated with 40% of preterm deliveries. In light of the rise in levels of glucocorticoids (GC) in amniotic fluid associated with preterm labor, in the present study we examined the effects of GC on the expression of major ECM proteins in cultures of amnion epithelial cells recovered after digestion of human term amnions. Amnion cells were maintained with and without 10(-7) mol/L dexamethasone (DEX), and levels of the ECM protein fibronectin (FN) were determined by enzyme-linked immunosorbent assay. DEX treatment reduced FN expression in amnion epithelial cells to 15-30% of control levels and reduced FN expression in placental cells to 30-50% of control levels. Conversely, DEX treatment weakly stimulated FN expression in chorion cell cultures. DEX treatment did not affect the total level of amnion cell protein, indicating that the effects of DEX in amnion cells did not result from a general reduction in protein synthesis. Cortisol and DEX reduced FN expression in amnion cells, with half-maximal effective concentrations of approximately 60 and 8 nmol/L, respectively. In immunoprecipitation studies, DEX treatment reduced FN and collagen III synthesis to 20% of control levels, suggesting that GC may coordinately reduce the synthesis of major ECM proteins in amnion cells. Similarly, DEX treatment reduced the levels of FN messenger ribonucleic acids in amnion cells to approximately 15% of control levels. DEX treatment also promoted a marked reduction in FN expression in amnion cells cultured in serum-free medium to 10-50% of control levels. Our results indicate that GC negatively regulate ECM protein expression in amnion epithelial cells, suggesting a potential role in the genesis of altered fetal membrane ECM protein expression associated with prematurely ruptured membranes.

Adult↗
PubMed1995

Plasminogen activator activity during decidualization of human endometrial stromal cells is regulated by plasminogen activator inhibitor 1.

Progesterone acts on the estradiol (E2)-conditioned human endometrium to induce decidualization of stromal cells. Consistent with these differential hormone actions in vivo, progestins regulate several end points of decidualization in human endometrial stromal cell monolayers, and E2 augments the effects of progestin. This study shows that in vitro decidualization of the stromal cells is accompanied by diminished plasminogen activator (PA) expression. Polyacrylamide gel electrophoretic separation after immunoprecipitation of biosynthetically labeled PAs revealed that medroxyprogesterone acetate (MPA) lowered levels of secreted tissue type PA (tPA) at 67 kilodaltons and urokinase type PA (uPA) at 55 kilodaltons. These levels were reduced further by E2 plus MPA despite a lack of response to E2 alone. Although tPA activity was readily measured by a chromogenic assay, detection of uPA activity required prior activation, indicating that uPA is released as the pro-uPA zymogen. Comparisons of levels of immunogenic PAs, as measured by specific enzyme-linked immunosorbent assays, with the corresponding catalytic activities revealed selective progestational inhibition of PA activity vs. antigen after 3 days of experimental incubation. Thus, 10(-7) mol/L MPA produced about a 2-fold greater reduction of levels of PA activity than that of its corresponding antigen. More strikingly, 10(-8) mol/L E2 plus 10(-7) mol/L MPA virtually eliminated both tPA activity (99% inhibition; P < 0.005) and uPA activity (93% inhibition; P < 0.005); the reductions in levels of the corresponding antigens were only about 50% of the control levels and did not attain statistical significance. Only after 3-6 days of incubation with E2 plus MPA was statistically significant inhibition achieved for immunogenic levels of both tPA (P < 0.05) and uPA (P < 0.005). Preferential inhibition of levels of PA activities compared with those of the corresponding PA antigens reflects the action of the potent PA inhibitor PAI-1. Thus, the concentration of PAI-1 in the stromal cell-conditioned medium at the end of 0-3 days exceeded those of tPA and uPA, respectively, by 28- and 12-fold in response to MPA and by 52- and 25-fold in response to E2 plus MPA. Extrapolation of these in vitro results to the events of the luteal phase, whose steroidal milieu is mimicked by E2 plus MPA, indicates that decidual cell-derived PAI-1 is a key regulator of proteolytic degradation of extracellular matrix and fibrinolysis during implantation and menstruation.

Cells, Cultured↗
PubMed1994

The role of progestationally regulated stromal cell tissue factor and type-1 plasminogen activator inhibitor (PAI-1) in endometrial hemostasis and menstruation.

The physiologic mechanisms whereby the human endometrium maintains hemostasis during endovascular trophoblast invasion, yet permits menstrual hemorrhage, are unknown. This paradoxical relationship was investigated by evaluating endometrial expression of tissue factor (TF), the primary initiator of hemostasis, and plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of fibrinolysis. We observed increased immunostaining for TF and PAI-1 in sections of decidualized stromal cells from luteal phase and gestational endometrium. To determine whether TF and PAI-1 expression are directly linked to decidualization, both endpoints were monitored in a well described in vitro model of decidualization. Thus, confluent stromal cell cultures were exposed to vehicle control, 10(-8) M estradiol (E2), 10(-8) to 10(-6) M medroxyprogesterone acetate (MPA) or both E2 + MPA for 2-24 days in serum-containing or defined media. The progestin enhanced the content of stromal cell-associated immunoreactive and functionally active TF and PAI-1 released into the medium and elevated levels of stromal cell TF and PAI-1 mRNA. While E2 alone was ineffective, it greatly augmented MPA-enhanced TF and PAI-1 protein and mRNA content. Dose-dependent effects on TF and PAI-1 content were observed between 10(-8) to 10(-6) M MPA +/- E2. Similar results were observed for decidual cells derived from first trimester endometrium and cultured in type 1 collagen gels. Following optimal induction of TF and PAI-1 expression by E2 + MPA in stromal cell cultures, removal of these steroids greatly reduced levels of both TF and PAI-1 protein and mRNA within 4 days. These studies suggest a mechanism whereby endometrial hemostasis is maintained during trophoblast invasion yet reduced at the end of nonfertile cycles to permit menses.

Cells, Cultured↗
PubMed1994

Negative regulation of placental fibronectin expression by glucocorticoids and cyclic adenosine 3',5'-monophosphate.

Fibronectin is a ubiquitous extracellular matrix (ECM) protein known to play a critical role in cell adhesion. In the present study we dissected the effects of glucocorticoids and cyclic adenosine 3',5'-monophosphate (cAMP) on FN expression in cultures of cytotrophoblasts isolated from human term placentas to identify compounds which may influence uterine-placental adherence. Based on immunoassay data, relative to controls, glucocorticoid treatment (1-1000 nM) of cytotrophoblasts specifically inhibited media levels of oncofetal FN (i.e., FNs bearing an oncofetal epitope) 65-92%. Treatment of cytotrophoblasts with androgens, estrogens, and progestins (1-1000 nM) did not markedly affect onfFN expression. Corticotropin-releasing hormone (CRH) treatment (200 nM) alone had no effect on levels on onfFN. In combination experiments using 100 nM dexamethasone (DEX), 1000 nM medroxyprogesterone acetate (MPA), 10 nM estradiol (E2) and 200 nM corticotropin-releasing hormone CRH, we observed that DEX treatment also promoted approximately an 85% reduction in media levels of onfFN. This indicated that glucocorticoids profoundly suppress FN expression in the presence of high concentrations of other steroids and pregnancy-associated paracrine effectors. To examine the influence of ECM protein composition on glucocorticoid-mediated suppression of onfFN expression, cells were inoculated on untreated culture wells or on wells coated with FN, laminin, or collagen I. We observed that DEX treatment downregulated onfFN levels 70-85% under each of these conditions, suggesting that glucocorticoid effects on FN expression were not dependent on the presence of an exogenous ECM. Treatment of cytotrophoblasts with 8-bromo-cAMP resulted in a dose-dependent reduction in onfFN expression to 3% of control levels with an EC50 of 150 nM. Based on Northern blotting, treatment of cytotrophoblasts with 100 nM DEX, 1 mM 8-bromo-cAMP, or 2 nM relaxin inhibited steady state levels of FN mRNA approximately 90% relative to controls. Our results suggest that during pregnancy glucocorticoids and compounds that alter intracellular concentrations of cAMP may profoundly suppress FN expression and therefore may have dramatic effects on uterine-placental adherence.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1994

Regulation of synthesis of the transformation-induced protein, leukocyte plastin, by ovarian steroid hormones.

Previous studies indicated that, among normal cells, only those of hemopoietic lineages expressed the abundant leukocyte phosphoprotein, L-plastin, and that activation of the L-plastin gene frequently occurred in malignant cells of solid tumors. We discovered that the gene encoding L-plastin contains potential estrogen and progesterone response elements upstream from its promoter, suggesting that L-plastin expression is subject to ovarian steroid regulation. To determine if L-plastin synthesis is regulated by ovarian steroids (estrogens and progestins), we examined cultured uterine endometrial stromal cells (SC) which are known to be responsive to ovarian steroids in a fashion that approximates the normal endometrium. Primary SC, which synthesized estrogen receptor and progesterone receptor mRNA transcripts, dramatically elevated L-plastin transcript synthesis in response to treatment with estradiol (E2) and medroxyprogesterone acetate (MPA). Stimulation of L-plastin synthesis by E2 and MPA was also evident by examination of protein synthesis using high-resolution two-dimensional gel electrophoresis and Western blotting. By contrast, SC that were propagated through multiple culture passages exhibited a coordinate decline in L-plastin, estrogen receptor, and progesterone receptor transcript levels and L-plastin protein synthesis. No other intracellular proteins could be found that were modulated significantly by E2 and MPA, but secretory protein synthesis was profoundly affected by E2 and MPA. Like L-plastin synthesis, hormone-mediated secretory protein synthesis was lost after propagation of the SC culture and reduction of estrogen receptor and progesterone receptor transcript synthesis. Our findings suggest that L-plastin synthesis is regulated coordinately with secretory protein synthesis in endometrial SC by estrogens and progestins.

Cells, Cultured↗
PubMed1994

Congenital nephrosis in low-risk pregnancies.

Congenital nephrosis is an autosomal recessive disorder requiring neonatal renal transplant for survival. The postnatal diagnosis rests upon the electron microscopic evaluation of the epithelial foot processes and basal membrane of the glomeruli. The prenatal diagnosis can be suspected in the presence of a positive family history with an amniotic fluid (AF) alpha-fetoprotein level greater than 5 standard deviations (SD) above the population mean accompanied by a negative AF acetylcholinesterase, absent haemoglobin F, and an unremarkable fetal sonographic examination. We reviewed our series of seven cases of congenital nephrosis fulfilling the above criteria; four cases had negative family histories, and in two cases the diagnosis of congenital nephrosis was further supported by the presence of elevated AF albumin concentrations. We conclude that (1) the prenatal diagnosis of congenital nephrosis is feasible in a low-risk population, and (2) an elevated AF albumin concentration may represent an additional marker for the diagnosis of congenital nephrosis, even though false-negative results have been reported.

Amniotic Fluid↗
PubMed1994

Increased interleukin-6 concentrations in cervical secretions are associated with preterm delivery.

OBJECTIVE: This study sought to determine whether elevated concentrations of interleukin-6 in the cervical and vaginal secretions of patients between 24 and 36 weeks' gestation predicted subsequent preterm delivery and/or identified those preterm deliveries associated with maternal infectious morbidity. STUDY DESIGN: A cohort study was undertaken with cervical and vaginal samples collected from 161 consenting patients seen at 3- to 4-week intervals between 24 and 36 weeks. Levels of interleukin-6 were measured by immunoassay. Demographic, obstetric, neonatal, and laboratory data were analyzed by Fisher's exact test, Student t test, or Wilcoxon rank sum test, linear and multiple logistic regression, and receiver-operator characteristic curve analysis. RESULTS: There were 4.2-fold and 3.4-fold increases in maximal cervical and vaginal interleukin-6 concentrations, respectively, among patients with preterm deliveries versus term deliveries. The receiver-operator characteristics curve analysis indicated that a single cervical interleukin-6 value > 250 pg/ml of sample buffer, present between 24 and 36 weeks' gestation, optimally identified patients with subsequent preterm deliveries versus term deliveries (sensitivity 50.0%, 95% confidence interval 33.2% to 66.8%; specificity 85.0%, 95% confidence interval 78.8% to 91.2%; positive predictive value 47.2%, 95% confidence interval 30.9% to 63.5%; negative predictive value 86.4%, 95% confidence interval 80.4% to 92.4%). The optimal vaginal interleukin-6 cutoff value (> 125 pg/ml) proved less sensitive (45.5%, 95% confidence interval 28.5% to 62.4%) but equally specific (86.6%, 95% confidence interval 80.7% to 92.5%). Multiple logistic regression indicated that a cervical interleukin-6 level > 250 pg/ml was an independent predictor of preterm delivery (adjusted odds ratio 4.8, 95% confidence interval 1.7 to 14.3). Cervical interleukin-6 levels did not correlate with cervical change or gestational age at sampling. Among patients delivered preterm there were no differences in the mean white blood cell count on admission or the prevalence of vaginal pathogens, alkaline vaginal pH, chorioamnionitis, or endometritis among patients with cervical interleukin-6 values > 150 or < or = 250 pg/ml. CONCLUSIONS: Cervical interleukin-6 is a relatively insensitive, although fairly specific discriminator of patients with subsequent preterm deliveries. Among patients delivered preterm, elevated cervical interleukin-6 values are not apparently associated with maternal infectious morbidity.

Adolescent↗
PubMed1994

Reduction of annexin-V (placental anticoagulant protein-I) on placental villi of women with antiphospholipid antibodies and recurrent spontaneous abortion.

OBJECTIVE: The mechanism by which antiphospholipid antibodies are associated with pregnancy loss and thromboembolic conditions has yet to be elucidated. Annexin-V, an anticoagulant phospholipid-binding protein, is normally present in syncytiotrophoblasts lining the placental villi, where it may play a role in the maintenance of intervillous blood fluidity. We therefore investigated the distribution of annexin-V in placentas of patients with antiphospholipid antibodies in situ and then used short-term villous cultures to study the direct effect of antiphospholipid antibodies on the immunolocation of annexin-V. STUDY DESIGN: We performed a blinded study by means of computerized morphometric analysis of placental tissues that were stained for annexin-V with affinity-purified polyclonal antibody in an avidin-biotin peroxidase system. The distribution of villous surface annexin-V on cross sections of placentas of patients with antiphospholipid antibodies was compared with that of placentas from patients with uncomplicated pregnancies, elective abortions, and pregnancy losses not associated with antiphospholipid antibodies (n = 8 for each group). We quantitated villous surface annexin-V in cultured placental villi that were incubated with antiphospholipid antibodies immunoglobulin G compared with normal immunoglobulin G and measured annexin-V levels by enzyme-linked immunosorbent assay in conditioned media and in the villi. RESULTS: The mean villous surface annexin-V of the group with antiphospholipid antibodies was 26.2% +/- 17% (SD) versus 93.9% +/- 5.7% in the normal control group (p < 0.0001). Villi from patients undergoing elective abortions and with pregnancy losses that were not attributed to antiphospholipid antibodies also showed higher mean villous surface annexin-V levels (86.9% +/- 10.6% and 83.5% +/- 11.3%, respectively, p < 0.0001). Organ culture of normal placental villi with affinity-purified immunoglobulin G from patients with antiphospholipid antibodies showed a dose-dependent decrease of villous surface annexin-V over a concentration range of 1.5 micrograms/ml to 1.5 mg/ml. Annexin-V concentrations in conditioned media were significantly lower in the presence of antiphospholipid antibodies immunoglobulin G compared with normal immunoglobulin G (49.4 +/- 8.9 ng/gm wet weight vs 57.2 +/- 11.5 ng/gm, respectively, p < 0.05). In contrast, the mean level of annexin-V in placental villi incubated with antiphospholipid antibodies immunoglobulin G was greater than in villi incubated with normal immunoglobulin G, 1328 +/- 130 ng/gm wet weight versus 1183 +/- 165 ng/gm (p < 0.02). CONCLUSIONS: Patients with antiphospholipid antibodies and a history of previous pregnancy losses have a significant reduction in annexin-V immunostaining on placental villous surfaces, and antiphospholipid antibodies immunoglobulin G can directly decrease levels of villous surface annexin-V on cultured placental villi. Assays of annexin-V in the conditioned media and cell pellets of cultured placental villi suggest that the mechanism for antiphospholipid antibodies-mediated reduced annexin-V surface staining is an inhibition of annexin-V transport to the villous surface rather than displacement by antiphospholipid antibodies from the surface. This antiphospholipid antibodies-induced deficiency of placental surface annexin-V may contribute to the placental thrombosis observed in these patients.

Abortion, Habitual↗
PubMed1994

Fetal membrane rupture is associated with the presence of insulin-like growth factor-binding protein-1 in vaginal secretions.

OBJECTIVE: Our purpose was to determine whether detection of insulin-like growth factor-binding protein-1 in vaginal secretions could be used in the diagnosis of fetal membrane rupture. STUDY DESIGN: Consenting patients (n = 105) with complaints suspicious of membrane rupture between 24 and 42 weeks of gestation who had no evidence of placenta previa were enrolled in the study. The diagnosis of membrane rupture required at least two of the following findings on vaginal examination: pooling of fluid, positive Nitrazine paper (Bristol-Myers Squibb, Cherry Hill, N.J.) test, or microscopic evidence of ferning. A swab of the posterior vaginal fornix was obtained, placed in sample buffer, and analyzed for insulin-like growth factor-binding protein-1 by immunoassay. Data analysis included chi 2 analysis, Student t test, or Mann-Whitney U test and linear regression and receiver operating characteristic curve analysis. RESULTS: A total of 78 (74.3%) patients met the criteria for membrane rupture. There was a highly significant difference in mean vaginal insulin-like growth factor-binding protein-1 concentrations between patients with and without clinical evidence of membrane rupture (553.6 +/- 731.4 micrograms/L vs 3.0 +/- 7.3 micrograms/L, p = 0.0002). Receiver operating characteristic curve analysis demonstrated that the optimal identification of patients with membrane rupture was achieved with an insulin-like growth factor-binding protein-1 value > 3 micrograms/L (sensitivity 74.4%, 95% confidence interval 64.7% to 84.0%; specificity 92.6%, 95% confidence interval 82.7% to 102.5%; positive predictive value 96.7%, 95% confidence interval 92.1% to 101.2%; negative predictive value 55.6%, 95% confidence interval 41.0% to 70.1%). CONCLUSIONS: The presence of vaginal insulin-like growth factor-binding protein-1 is highly predictive of membrane rupture, identifying 74.4% of affected patients with a very low false-positive rate.

Adult↗
PubMed1994

Low concentrations of vaginal fetal fibronectin as a predictor of deliveries occurring after 41 weeks.

OBJECTIVE: This study sought to determine whether low concentrations of fetal fibronectin in the cervical and vaginal secretions of patients at 39 weeks' gestation predicted pregnancies progressing beyond 41 weeks' gestation. STUDY DESIGN: A retrospective cohort study was undertaken using cervical and vaginal samples collected from 75 consenting patients during the thirty-ninth week of gestation. Levels of fetal fibronectin were measured by immunoassay. Demographic, obstetric, neonatal, and laboratory data were analyzed by Fisher's exact test, Student t test or Wilcoxon's rank-sum test, multiple logistic regression, and receiver-operating characteristic curve analysis. RESULTS: There was a 35.5-fold increase in vaginal fetal fibronectin concentrations among patients delivered at < 41 weeks compared with those delivered at > or = 41 weeks. The receiver-operating characteristic curve analysis indicated that the optimal fetal fibronectin predictor of prolonged pregnancies was a vaginal fetal fibronectin value < 60 ng/ml present between 39 weeks 0 days and 39 weeks 6 days' gestation (sensitivity 95.7%, 95% confidence interval 87.3% to 100.0%; specificity 44.2%, 95% confidence interval 30.7% to 57.7%; positive and negative predictive values 43.1% [95% confidence interval 29.5% to 56.7%] and 95.8% [95% confidence interval 87.8% to 100.0%], respectively). The relative risk for a prolonged pregnancy resulting from a vaginal fetal fibronectin value < 60 ng/ml was 10.4 (1.5 to 72.4). Among patients with a vaginal fetal fibronectin value > or = 60 ng/ml, 80.8% were delivered within 1 week and 92.3% within 10 days of sampling. In contrast, among patients with vaginal fetal fibronectin value < 60 ng/ml 63.3% remained undelivered after 1 week. After parity and cervical dilation were controlled for, multiple logistic regression demonstrated that a vaginal fetal fibronectin value < 60 ng/ml was a significant independent predictor of pregnancies delivered at > or = 41 weeks (adjusted odds ratio 12.8 [95% confidence interval 1.5 to 107.2]). CONCLUSIONS: A vaginal fetal fibronectin value > or = 60 ng/ml at 39 weeks' gestation is predictive of delivery within 10 days, whereas values < 60 ng/ml identify 95% of pregnancies progressing past 41 weeks' gestation. This data may allow for the prediction of postdates pregnancies, thus facilitating appropriate obstetric interventions.

Adult↗
PubMed1994

The expression of the placental anticoagulant protein, annexin V, by villous trophoblasts: immunolocalization and in vitro regulation.

We evaluated the histological and ultrastructural localization of the potent anticoagulant protein, annexin V, at the light and electron microscopic levels, using immunohistochemistry and an immunogold method. Annexin V was found to localize to the microvillar surface of the villous syncytiotrophoblasts. Isolated villous-derived trophoblasts were then utilized to evaluate the expression of annexin 1 protein mRNA in response to syncytialization in vitro, as well as to exposure to adenylate cyclase and protein kinase C agonists. Levels of immunoreactive annexin V released into the conditioned media and associated with cell protein were assessed by ELISA while levels of annexin V mRNA were evaluated by Northern analysis. No significant change in either media or cell-associated annexin V concentrations were detected over time in culture or in response to 1.5 mM 8-bromo-cyclic-adenosine-monophosphate (8-b-cAMP) or 0.15 nM phorbol ester myristic acid (PMA). These results indicate that annexin V is ideally positioned to inhibit intervillous thrombosis and maintain the fluidity of the intervillous circulation. Moreover, the absence of trophoblast annexin V regulation by intracellular second messenger regulators suggests that this crucial placental anticoagulant factor is constitutively produced.

Annexin A5↗
PubMed1994

Use of cervical prostaglandin E2 gel in patients with previous cesarean section.

The aim of this study was to determine whether preinduction cervical ripening with prostaglandin E2 (PgE2) gel in patients with one previous cesarean section may be used with the same safety and efficacy as in patients without a uterine scar. Primiparous patients (n = 94) with one previous cesarean section were retrospectively compared to nulliparous patients (n = 866). Both groups underwent preinduction cervical ripening with 2 mg intracervical PgE2 gel. Logistic regression was performed to control for confounding factors. Our statistical power was 90% for detecting a doubling of the complication rate, from 10 to 20%. There were no significant differences in the duration of ruptured membranes or length of labor between the two groups. No significant differences were detected in the rate or indications for cesarean section, presence of thick meconium, epidural anesthesia use, amnionitis, or maternal and neonatal morbidity. There were no cases of uterine rupture in either group. PgE2 gel may be used with the same safety and efficacy in patients with previous cesarean section as in nulliparas.

Administration, Intravaginal↗
PubMed1994

The immunobiology and obstetrical consequences of antiphospholipid antibodies.

Two classes of antiphospholipid antibodies (APA) are associated with adverse pregnancy outcomes. Those APA identified by immunoassays using phospholipid-coated surfaces (e.g., anticardiolipin antibodies) seem to bind to the 57 kD anticoagulant protein, beta 2-glycoprotein-I, when complexed with anionic phospholipid bilayers. Such APA may or may not prolong phospholipid-dependent clotting assays. A second class of APA are identified by their interference with phospholipid-dependent clotting assays (i.e., lupus anticoagulants). The latter bind to phospholipids present in a unique hexagonal phase either alone or complexed with prothrombin or beta 2-glycoprotein-I. There is evidence that both classes of APA are directly responsible for adverse pregnancy outcomes including spontaneous abortions, stillbirths, fetal growth retardation, thrombosis, thrombocytopenia, and preeclampsia. Putative APA-mediated pathogenic mechanisms include intervillous thrombosis, intravillous infarctions and decidual vasculopathy. The thrombogenicity of APA may result from their interference with endothelial phospholipids required for antithrombin III and protein C and S anticoagulant activity and prostacyclin synthesis and/or increased endothelial expression of the procoagulants: tissue factor, von Willebrand factor, platelet-activating factor, and plasminogen activator inhibitor type-1. Other prothrombotic properties seem to include: increased platelet aggregation, and reduced beta 2-glycoprotein-1 and annexin V anticoagulant activity. Rigorous diagnostic criteria must be applied to the detection of both classes of APA because the prevention of adverse pregnancy outcomes requires potentially hazardous anticoagulant therapy.

Animals↗
PubMed1994

Developmental regulation of glucocorticoid-mediated effects on extracellular matrix protein expression in the human placenta.

The extracellular matrix (ECM) protein fibronectin (FN) is a critical regulator of uterine-placental adherence. In the present report we compared the effects of glucocorticoids on FN expression in cytotrophoblast cultures isolated from human first trimester and term placentas to elucidate potential steroid-dependent cellular mechanisms associated with human parturition. Based on immunoassays, treatment of first trimester cytotrophoblasts with 10(-7) M dexamethasone (DEX) for 2 cr 4 days reduced medium levels of oncofetal FN (onfFN; i.e. FNs bearing an oncofetal epitope) to approximately 80% of control levels. Conversely, treatment of cytotrophoblasts isolated from term placentas with DEX dramatically reduced medium levels of onfFN to approximately 12% of control values. Treatment of both first trimester and term cells with 10(-6) M progestin, mineralocorticoid, or estrogen had no significant effect on onfFN expression in either cell type. Glucocorticoids specifically down-regulated medium levels of onfFN in term cells, but not in first trimester cells. In contrast, DEX treatment promoted an approximately 3- to 7-fold increase in levels of hCG in both first trimester and term cytotrophoblasts, suggesting that the effects of glucocorticoid on FN and hCG expression are elicited through independent cell-signaling pathways. In first trimester cells, DEX promoted a reduction in rates of FN and laminin synthesis to 60-70% of control levels. In term cells, DEX treatment reduced levels of FN and laminin synthesis to approximately 10% of control levels. Similarly, DEX treatment down-regulated levels of FN mRNA to approximately 60% and 10% of control values in first trimester and term cells, respectively. The first trimester of human pregnancy is associated with low levels of glucocorticoids and reduced glucocorticoid responsiveness. These conditions would favor high levels of placental ECM protein synthesis, thus stabilizing uterine-placental adherence. Conversely, elevated levels of glucocorticoids near parturition and increased glucocorticoid responsiveness would inhibit placental ECM protein synthesis, reducing uterine-placental adherence and promoting the separation of placenta from uterus.

Cells, Cultured↗
PubMed1994

Ovarian steroid-modulated stromelysin-1 expression in human endometrial stromal and decidual cells.

This study examined steroid-regulated expression of the metalloproteinase stromelysin-1 in primary human endometrial stromal and decidual cells. Immunoblot analysis using a specific polyclonal antibody against stromelysin-1 revealed that the progestin medroxyprogesterone acetate (MPA) produced a time-dependent reduction in a band at 50,000 mol wt. Although the cells were refractory to estradiol (E2) alone, E2 plus MPA further reduced the intensity of this stromelysin-1 zone. By 6 days of incubation, MPA inhibited levels of secreted stromelysin-1 by one third, and E2 plus MPA inhibited stromelysin-1 levels by two thirds compared with the control values. This differential responsiveness of the stromal cells to the two steroids is reported for several biochemical end points of decidualization. Northern analysis indicated pronounced inhibition of stromelysin-1 messenger ribonucleic acid (mRNA) by E2 plus MPA over a concentration range that simulated circulating progesterone levels of the luteal phase (10(-8) mol/L) through pregnancy (10(-6) mol/L). After suppression of stromelysin-1 expression in the stromal cell monolayers by E2 plus MPA, steroid withdrawal led to a several-fold enhancement of stromelysin-1 mRNA by 4 days and of the stromelysin-1 protein by 7 days. Given its actions in degrading several extracellular matrix components and activating other MMP zymogens, steroid withdrawal-enhanced stromelysin-1 activity could mediate a proteolytic cascade that promotes the rapid tissue destruction and vascular disruption associated with menstruation. Stromelysin-1 expression by cultured decidual cells isolated from first trimester endometrium was also reduced by MPA and synergistically reduced by E2 plus MPA. As activation of the 92-kilodalton gelatinase/type IV collagenase, a crucial mediator of trophoblast invasiveness, is stromelysin-1 dependent, reduced decidual stromelysin-1 production could help to limit trophoblast invasion.

Abortion, Induced↗
PubMed1994

Biological mechanisms underlying RU 486 clinical effects: inhibition of endometrial stromal cell tissue factor content.

Despite the pronounced hemorrhagic effects of RU 486 administration on luteal phase and early gestational endometrium, no information is available on the effect of RU 486 on endometrial hemostatic potential. The expression of endometrial stromal cell tissue factor (TF), the primary initiator of hemostasis, has been shown to be progestationally regulated in vivo and in vitro. To evaluate the effects of RU 486 on progestin-enhanced TF expression, confluent stromal cell cultures derived from proliferative phase endometria were exposed to vehicle control, 10(-8) mol/L estradiol (E2), 10(-6) mol/L dexamethasone, 10(-7) mol/L medroxyprogesterone acetate (MPA), E2 plus MPA, E2 plus 10(-6) mol/L progesterone (P), or 10(-6) mol/L RU 486 alone or with E2 plus MPA or E2 plus P for 3-4 days. Compared to the vehicle control, E2, dexamethasone, and RU 486 alone had no effect on the content of immunoreactive and functionally active TF protein, whereas MPA increased and the combination of E2 and MPA further increased TF protein content. Similarly, E2 and P enhanced the stromal cell TF content. These progestin effects were blocked by RU 486. Similar results were obtained for steady state TF messenger ribonucleic acid (mRNA) levels. Possible RU 486-mediated reversal of progestin-enhanced stromal cell TF expression was assessed by incubating confluent cultures in E2 plus MPA for 3-10 days to enhance TF content, then washing the cultures and reexposing them to either E2 plus MPA or to RU 486 alone or with E2 plus MPA for 3, 4, or 7 days. Exposure to RU 486 alone or with E2 plus MPA greatly reduced levels of stromal cell TF protein and mRNA expression compared to those in cultures maintained in E2 plus MPA. These findings demonstrate that RU 486 not only blocks but also reverses in vitro progestin-enhanced stromal cell TF protein and mRNA expression, suggesting an additional mechanism for RU 486-induced menses and early abortion.

Cells, Cultured↗