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D J Dudley

Publications and source records attributed to D J Dudley.

At least 37 records · Page 2Linked to original sources
PubMed1996

Significant decrease in parathyroid hormone-related protein concentrations in amniotic fluid with labour at term but not preterm.

It has been determined whether amniotic fluid concentrations of parathyroid hormone-related protein (PTHrP) change with labour. An evaluation of which cells from intrauterine tissues might produce PTHrP has also been conducted. Amniotic fluid was obtained by amniocentesis from women: (1) at term, not in labour; (2) in normal term labour; (3) in preterm labour, undelivered within one week; (4) in preterm labour, delivered within one week; (5) in preterm labour associated with clinical chorioamnionitis; and (6) who were gestation-matched controls for chorioamnionitis patients-women in this group were similar to those in Group 4 but were different patients. Amnion, chorion, and decidual cells were grown by standard techniques and incubated with interleukin-1 beta (IL-1 beta). PTHrP was assayed in duplicate samples of amniotic fluid or tissue culture media using an immunoradiometric assay. There was a significant reduction in amniotic fluid concentrations of PTHrP during labour at term. Preterm labour was not associated with significant changes in amniotic fluid concentrations of PTHrP although a trend for reduced concentrations was observed. Amnion and chorion produced measurable quantities of PTHrP and rates of production were increased by treatment with IL-1 beta. Decidual cells did not produce detectable amounts of PTHrP. Hence, labour at term is associated with a decrease in amniotic fluid PTHrP concentrations that may reflect reduced amnion production, which in turn may play a permissive or active role in the mechanism(s) of parturition. These data support the view that the mechanisms that control term and preterm labour may be regulated differently.

Amniocentesis↗
PubMed1996

Induction of preterm birth in mice by RU486.

We hypothesized that treatment of pregnant mice with the progesterone receptor antagonist RU486 might cause preterm labor and result in the delivery of live pups. We also hypothesized that RU486 administration would alter prostaglandin production by decidual explants taken from these pregnancies. C3H/HeN females mated with C57BI/6 males were injected with a single s.c. dose of RU486 on Days 12-14 of gestation. Three doses were tested (50 micrograms, 150 micrograms, and 250 micrograms), and the mice were observed for evidence of delivery. The time course of delivery was determined in a second experiment using 150 micrograms of RU486, and care was taken to observe the condition of the delivered pups. In a third experiment, mice were killed when delivery commenced after injection with 150 micrograms of RU486, and decidual explants were prepared. Controls that had received injections of vehicle were killed at the same time, and decidual explants were established. Media were removed after 24 h and analyzed for prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha) by RIA and for interleukin 6 (IL-6) by ELISA. Two of 3 mice given 50 micrograms of RU486 delivered 16 pups prematurely. All 3 mice given 150 micrograms of RU486 delivered 22 pups prematurely, and 2 of 3 given 250 micrograms of RU486 delivered 12 pups prematurely. Of mice treated with 150 micrograms of RU486, none delivered within 12 h; 2 of 7 delivered within 15 h; and 6 of 7 delivered within 22 h. All pups appeared to be healthy, with no evidence of placental infarction or death. PGE2, PGF2 alpha, and IL-6 production by decidual explants was significantly greater in tissues taken from RU486-treated mice (n = 6) than in controls (n = 3). In summary, RU486 reliably induced preterm birth of the mice within 24 h after s.c. injection. This was associated with increased decidual prostaglandin and cytokine production and thus may mediate preterm labor. Inducing preterm birth with RU486 in a mouse model may be useful in investigations of the mechanism(s) of preterm labor.

Abortifacient Agents, Steroidal↗
PubMed1996

Regulation of cultured human chorion cell chemokine production by group B streptococci and purified bacterial products.

PROBLEM: To determine if different strains of group B streptococci (GBS) and purified bacterial products regulate chemokine production by cultured human chorion cells. METHOD OF STUDY: Primary cultures of human chorion cells were established from placentae isolated from normal women at term gestation having repeat cesarean section. Five different strains of heat-killed GBS were incubated with confluent chorion cells at 10(7) bacteria/ml for 16 hours at 37 degrees C. In separate experiments, lipoteichoic acid and sialic acid at various concentrations were incubated with chorion cells for 16 hours at 37 degrees C. Culture supernatants were collected and then assayed to determine concentrations of interleukin-8 (IL-8) and macrophage inflammatory protein-1 alpha (MIP-1 alpha) by ELISA. RESULTS: We found that GBS stimulated chorion cell production of MIP-1 alpha in a strain-specific fashion. We also found that both lipoteichoic acid and sialic acid stimulated concentration-dependent increases in chorion cell IL-8 production. Chorion cells, however, did not increase MIP-1 alpha production in response to either lipoteichoic acid or sialic acid. Two strains of GBS tested induced concentration-dependent increases in both IL-8 and MIP-1 alpha, but both stimulated IL-8 production to a greater extent. Similarly, IL-1 beta also caused chorion cells to produce more IL-8 than MIP-1 alpha. CONCLUSIONS: Our data are the first to show that GBS and purified bacterial products can stimulate chemokine production by fetal gestational tissues. We suggest that chorion cells may produce specific types of chemokines to attract different types of inflammatory cells and thus may participate in the pathophysiology of infection-mediated preterm labor by directing specific inflammatory responses.

Amniotic Fluid↗
PubMed1995

Regulation of human decidual cell macrophage inflammatory protein-1 alpha (MIP-1 alpha) production by inflammatory cytokines.

PROBLEM: Inflammation of human gestational tissues is a key pathophysiologic event in the genesis of infection-associated preterm labor. Human gestational tissues produce several inflammatory cytokines after stimulation with bacterial products. These include interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF alpha), and IL-6. Another class of cytokines includes chemokines of the "C-C" subclassification such as macrophage inflammatory protein-1 alpha (MIP-1 alpha). The purpose of this study was to determine whether cultured human decidual cells produce MIP-1 alpha in response to other inflammatory cytokines. METHODS: Various concentrations of IL-1 beta, TNF alpha, IL-6, and IL-4 were incubated with confluent monolayer cultures of decidual cells isolated from normal term placentae for 16 h at 37 degrees C, and MIP-1 alpha concentrations in culture supernatants were measured by ELISA. RESULTS: We found that incubation of decidual cells with IL-1 beta, TNF alpha, and IL-4 resulted in significant concentration-dependent increases in MIP-1 alpha production. IL-6 had no effect on MIP-1 alpha production. CONCLUSIONS: Our data are the first to show that human decidual cells in culture produce MIP-1 alpha in response to other inflammatory cytokines. We suggest that decidual cell production of MIP-1 alpha is an important early event in the pathophysiology of infection-associated preterm labor.

Cells, Cultured↗
PubMed1995

Bacterial lipopolysaccharide-mediated fetal death. Production of a newly recognized form of inducible cyclooxygenase (COX-2) in murine decidua in response to lipopolysaccharide.

Maternal infection is a cause of spontaneous abortion and preterm labor in humans, but the pathophysiology is unclear. We hypothesized that eicosanoids play an important role in infection-driven pregnancy loss. To investigate this hypothesis, we administered lipopolysaccharide (LPS) to pregnant C3H/HeN mice and found that LPS administration caused fetal death in a dose-dependent fashion. Pretreatment with indomethacin significantly decreased the proportion of fetal death from 83% to < 25% in mice injected with 10 micrograms of LPS. Also, decidual explants from LPS-treated mice produced significantly more inflammatory eicosanoids, including prostaglandins E2 and F2 alpha and thromboxane B2, than controls. We investigated the regulatory mechanisms responsible for increased decidual prostanoid production in response to LPS. Western and Northern blots demonstrated that decidual protein and mRNA levels of a recently recognized highly inducible form of cyclooxygenase, COX-2, were substantially increased in mice treated with LPS. Induction of COX-2 was rapid: mRNA was detected 30 min after LPS injection. In contrast, another form of cyclooxygenase, COX-1, was only minimally induced in response to LPS. Our data indicate that LPS induces decidual prostanoid production via increased COX-2 expression. Since LPS-mediated fetal death is markedly diminished by pretreatment with indomethacin, COX-2-mediated eicosanoid production is likely a key pathophysiologic event in LPS-mediated fetal death.

Abortion, Spontaneous↗
PubMed1994

Clinical value of amniotic fluid interleukin-6 determinations in the management of preterm labour.

OBJECTIVE: To ascertain whether the determination of amniotic fluid interleukin-6 (IL-6) concentrations would be a useful clinical test in the management of women with preterm contractions. SETTING: The labour and delivery unit and the Fetal Diagnostic Centre at the University of Utah. SUBJECTS: Pregnant women at various stages of gestation in the third trimester. DESIGN: Amniotic fluid samples were collected from women experiencing one of four clinical scenarios: 1. term pregnancy, not in labour with no evidence of intrauterine infection; 2. normal term labour with no evidence of infection; 3. preterm labour with no evidence of infection and undelivered within one week of sampling; and 4. preterm labour and delivered within seven days of sample collection. Amniotic fluid was obtained by amniocentesis or at the time of amniotomy or hysterotomy. IL-6 in each specimen was determined by a specific rapid ELISA. RESULTS: Amniotic fluid IL-6 levels, given as mean (SEM) in the four groups of women listed were: 1. term pregnancy, not in labour: 20.9 (7.2) pg/ml (n = 60); 2. normal term labour with no infection: 554 (90.7) pg/ml (n = 46); 3. preterm labour with no evidence of infection, undelivered: 47.0 (17.2) pg/ml (n = 35); and 4. preterm labour, delivered: 456.7 (101.7) pg/ml (n = 40). There was no significant difference in the means of amniotic fluid IL-6 for the term labour and preterm labour delivered groups. In general, amniotic fluid IL-6 levels during term labour increased with advancing cervical dilation. There was no correlation of cervical dilation and amniotic fluid IL-6 levels in women having preterm delivery. Receiver-operator curves revealed optimal IL-6 levels for discrimination of labour at term to be 50 pg/ml and for preterm delivery to be 200 pg/ml. CONCLUSIONS: IL-6 can readily be detected in the amniotic fluid of most women who are in active labour, regardless of gestational age. Our data suggest that amniotic fluid IL-6 determinations may be clinically useful in the management of preterm labour.

Adult↗
PubMed1993

Adaptive immune responses during murine pregnancy: pregnancy-induced regulation of lymphokine production by activated T lymphocytes.

OBJECTIVE: We hypothesized that the lymphokine production by splenocytes and decidual lymphocytes would be altered because of changes in immunoregulation during pregnancy. STUDY DESIGN: Splenocytes and decidual lymphocytes were isolated from syngeneic and allogeneic pregnant mice at different times of gestation. The lymphocytes (10(7) cells/ml) were stimulated with anti-CD3 antibody, and culture supernatants were assayed for several lymphokines, including interleukin-2, interferon-gamma, interleukin-4, interleukin-6, granulocyte-macrophage colony-stimulating factor, and interleukin-3. Statistical analysis was by analysis of variance or paired t test. RESULTS: Activated splenocytes produced significantly less interleukin-2 and more interleukin-4, interleukin-6, and interleukin-3 as murine pregnancy advanced. Production of interferon-gamma and granulocyte macrophage colony-stimulating factor by activated splenocytes peaked in the first 8 to 14 days of pregnancy. Stimulated decidual lymphocytes produced modest amounts of interleukin-6, granulocyte-macrophage colony-stimulating factor, and interleukin-3 during pregnancy but no interleukin-2, interferon-gamma, or interleukin-4. Similar results were found for both syngeneic and allogeneic matings. CONCLUSIONS: Our findings indicate that splenocyte lymphokine production favors interleukin-4 production over interleukin-2 production. This finding suggests that antibody production would be enhanced and cytotoxic cellular immune responses inhibited during pregnancy. These changes occurred regardless of mating partner, suggesting that the specific antigenic stimulus during normal pregnancy does not regulate lymphokine production. Activated splenocytes and decidual lymphocytes were found to differ in their capacity to produce lymphokines, indicating that the decidua constitutes a distinct and unique immunologic microenvironment.

Animals↗
PubMed1993

A murine model of preterm labor: inflammatory mediators regulate the production of prostaglandin E2 and interleukin-6 by murine decidua.

Inflammatory processes may be important in the initiation and propagation of uterine contractions and preterm labor in human pregnancies. Recently, a murine model of preterm labor has been described. The purpose of our study was to determine whether murine decidua responds to inflammatory mediators, such as lipopolysaccharide (LPS) and the inflammatory cytokines interleukin (IL)-1 beta and tumor necrosis factor (TNF). Allogeneic pregnant mice (C3H/Hen females mated with C57/B6 males) were killed at 12-14 days of pregnancy, decidual tissue was isolated, and explants were placed on the polycarbonate membrane of Costar Transwell inserts. Initial validation studies of this explant system, including biochemical and histologic evaluations, indicated that the decidual tissue remained intact, viable, and responsive to IL-1 beta for at least 5 days in explant culture. Treatment of murine decidual explants with LPS, IL-1 beta, and TNF resulted in significant increases in the production of prostaglandin E2 (PGE2) and IL-6. Thus the regulation of PGE2 and IL-6 production from murine decidua by LPS and inflammatory cytokines is similar to findings previously reported for human decidua. Our findings are consistent with the view that the pathophysiology of infection-induced preterm labor in the mouse may be similar to that in human pregnancy and supports the continued development of murine models of preterm labor.

Animals↗
PubMed1993

Inflammatory mediators regulate interleukin-8 production by cultured gestational tissues: evidence for a cytokine network at the chorio-decidual interface.

The physiology of parturition, and the pathophysiology of preterm labor, is incompletely understood. Infection of gestational tissues may account for a significant proportion of women who experience preterm labor. Interleukin-8 (IL-8), or neutrophil-activating protein (NAP-1), is a potent chemotactic and activating factor for neutrophils and has been implicated in the pathogenesis of inflammatory injury to skin and lung, but has yet to be described in gestational tissues. Cultured chorion and decidual cells obtained from normal human pregnancies were used to evaluate whether these tissues produce IL-8 basally and in response to inflammatory cytokines. As measured by specific IL-8 RIA, chorion and decidual cells produce IL-8 constitutively and in response to IL-1 beta and tumor necrosis factor. Cotreatment of chorion cells or decidual cells with IL-1 beta and actinomycin D or cycloheximide abrogated IL-8 production. Northern blot analysis confirmed that IL-1 beta stimulation of chorion and decidual cells resulted in increased IL-8 messenger RNA expression. Our data support the concept that a complex cytokine network between maternal and fetal gestational tissues exists, and that activation of inflammatory cytokine production in these tissues, including IL-8, likely contributes to the pathophysiology of infection-induced preterm labor.

Blotting, Northern↗
PubMed1992

Amnion cell biosynthesis of interleukin-8: regulation by inflammatory cytokines.

The cellular constituents of the placenta are important participants in the recruitment and trafficking of inflammatory cells within the placenta. In infection-induced labor, gestational tissues synthesize and release a variety of inflammatory cytokines whose effects include increased prostaglandin biosynthesis and the initiation of uterine contractions. Interleukin-8 (IL-8), a potent neutrophil chemoattractant, has been recently described as being elevated in the amniotic fluid of mothers with chorioamnionitis. We investigated the biosynthesis of IL-8 by human amnion cells and its regulation by other inflammatory cytokines. Cultured amnion cells obtained from normal term placentae were found to produce IL-8 in response to pathophysiologic concentrations of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha (TNF-alpha). Treatment of amnion cells stimulated by IL-1 beta with cycloheximide resulted in increased IL-8 production, while incubation of IL-1 beta treated amnion cells with actinomycin D resulted in a concentration-dependent decrease in detectable amounts of IL-8. Northern blot analysis of cultured amnion cells stimulated with IL-1 beta demonstrated a rapid increase in IL-8 mRNA which peaked at 2-4 hr. These in vitro results suggest inflammation of gestational tissues in vivo may result in locally produced IL-8 and, in association with other inflammatory mediators, may be important in the pathophysiology of infection-induced labor.

Amnion↗
PubMed1992

A human endometrial explant system: validation and potential applications.

OBJECTIVE: Our objective was to describe an in vitro explant system to study the regulation of prostaglandin production by human endometrium. STUDY DESIGN: Segments of late-luteal-phase endometrium were obtained aseptically at the time of endometrial sampling. The endometrium was cut into 1 mm3 pieces and applied to the polycarbonate membrane of tissue-culture-well inserts for 12-well plates (Costar Transwell cell culture chamber inserts, 0.4 microns pore size). After placing the well inserts, culture medium was carefully applied. The explants were incubated at 37 degrees C in 5% carbon dioxide in air, and the culture medium was changed daily. RESULTS: Electron microscopic examination and lactate dehydrogenase determinations of the explants revealed cellular viability for < or = 5 days of culture. Endometrial explants responded to treatment with interleukin-1 beta and tumor necrosis factor by a concentration-dependent increase in the production of prostaglandin E2. Costimulation of late luteal endometrial explants with interleukin-1 beta (10 ng/ml) and progesterone (10(-6) mol/L) resulted in variable production of prostaglandin E2, suggesting that the histologic examination of the endometrium does not necessarily reflect the functional properties of the endometrium. CONCLUSIONS: Our data show that when used with human endometrial tissue this explant system maintains tissue viability and responsiveness for < or = 5 days. This approach to explant methods is simple and provides a flexible model to study the regulation of the production of bioactive substances by human endometrial tissue.

Culture Techniques↗
PubMed1992

Sera from preeclamptic patients contain factor(s) that stimulate prostacyclin production by human endothelial cells.

A relative decrease in endothelial cell prostacyclin production may be pivotal in the genesis of preeclampsia. We determined the effect of sera from preeclamptic women on prostacyclin production by monolayers of normal term human umbilical vein endothelial cells. Endothelial cells were incubated with media containing serum from patients with preeclampsia, non-hypertensive, gestational age-matched pregnant controls, or normal non-pregnant controls (N = 7, all groups). 6-Keto-prostaglandin F1 alpha, the stable metabolite of prostacyclin, was measured directly in the culture medium by radioimmunoassay. Treatment with preeclamptic sera, when associated with a statistically significant increase in prostacyclin metabolite production by endothelial cells. Thus, sera from women with preeclampsia stimulate rather than inhibit prostacyclin production by endothelial cells. We speculate that there is a factor in the sera of women with preeclampsia that functions to activate endothelial cells or which may play a role in the homeostatic mechanisms to balance reduced prostacyclin output in preeclampsia.

6-Ketoprostaglandin F1 alpha↗
PubMed1992

The immune system in health and disease.

For an immune response against an eliciting antigen, innate and adaptive immune mechanisms interact to provide a specific and appropriate response characterized by self-non-self discrimination and memory. This non-random process involves antigen presentation followed by T cell recognition and activation with the elaboration of T cell-derived lymphokines. The nature and amount of lymphokine production from antigen-activated T cells then determines the predominant immune response (e.g. cytotoxicity versus antibody). Exogenous regulatory factors, including steroid hormones, prostaglandins, and cytokines, modulate immune responsiveness. How these regulatory factors influence the immune response during specific host-parasite interactions determines the predominant immune response to specific antigen. As the regulation of the immune response is unravelled, new and powerful immunomodulatory therapies will be developed and utilized to improve the immune response and host survival.

Antigen-Presenting Cells↗
PubMed1992

Decidual cell biosynthesis of interleukin-6: regulation by inflammatory cytokines.

Intrauterine infection is an important cause of preterm labor and delivery and is characterized by increased production of inflammatory cytokines by gestational tissues. We have evaluated the biosynthesis of the inflammatory cytokine, interleukin-6 (IL-6), by human decidua and its regulation by other cytokines essential to the inflammatory process. We found that decidual cells secrete small amounts of IL-6 in the presence of growth medium supplemented only with 10% fetal calf serum. Interleukin 1 (alpha and beta) and tumor necrosis factor (TNF) all induced a significant concentration-dependent stimulation of IL-6 production by decidual cells. Treatment of decidual cells with actinomycin D or cycloheximide abrogated the increase in IL-6 production induced by IL-1 beta. Northern blot analysis of cultured decidual cells revealed an increase in IL-6 messenger RNA (mRNA) over time in response to IL-1 beta. These data indicate that IL-1 beta stimulates an increase in IL-6 mRNA and protein production, reflecting either direct gene activation or stabilization of IL-6 mRNA. The concentration range tested (0.1 to 10 ng/mL) of each cytokine is within the range of values found in the amniotic fluid of women destined to deliver preterm due to infection of gestational tissues. Our data suggest that IL-6 is produced by human decidua in response to inflammation and, in conjunction with other inflammatory mediators, may play a role in the pathophysiology of preterm labor due to infection.

Blotting, Northern↗
PubMed1992

The regulation of endothelin production in human umbilical vein endothelial cells: unique inhibitory action of calcium ionophores.

Endothelins (ETs) are a recently discovered family of small proteins that have potent long-lasting vasoconstrictive activities. Increased circulating concentrations of ETs have been found in hypertensive and renal disorders, including pregnancy-induced hypertension (PIH). PIH has been postulated to be the end result of endothelial cell damage and aberrant calcium metabolism. We evaluated the effects of calcium ionophores, calcium channel blockers, and two forms of cellular damage on ET production by human umbilical vein endothelial cells (HUVEC). Cells were grown to confluence and then incubated for 16 h with these treatments: physical trauma ("scratching"), oxidant damage (hydrogen peroxide, 1-20 mM), ionomycin (0.25-2.0 microM), A-23187 (10(-9)-10(-5) M), verapamil (0.22-22.0 microM), and nifedipine (2-200 micrograms/mL). ET production was determined using a commercial RIA that detects ET-1 and ET-2. Physical trauma enhanced ET production, whereas oxidant damage had the opposite effect. Both ionomycin and A-23187 caused concentration-dependent inhibition of ET production. Neither verapamil nor nifedipine consistently altered ET production. We conclude that specific forms of cellular damage can stimulate HUVEC ET production, although oxidant damage may be slightly inhibitory. Thus, enhanced ET levels in PIH may represent endothelial cell activation, rather than damage. HUVEC ET production is regulated in an inverse manner by intracellular calcium concentrations, suggesting a negative feedback from mediators of ET action on cells.

6-Ketoprostaglandin F1 alpha↗