Labor and infection. II. Bacterial endotoxin in amniotic fluid and its relationship to the onset of preterm labor

Yale University School of Medicine, Department of Obstetrics and Gynecology, New Haven, CT 06510-8063.
American Journal of Obstetrics and Gynecology (Impact Factor: 3.97). 06/1988; 158(5):1044-9.
Source: PubMed

ABSTRACT We have previously reported the detection of endotoxin in the amniotic fluid of patients with gram-negative intraamniotic infection. Endotoxin or lipopolysaccharide is a potent biologic product capable of inducing prostaglandin release from several cell types and, therefore, may be involved in the onset of human parturition in the presence of intraamniotic infection. This article describes a technique for the quantification of endotoxin in amniotic fluid. The method uses a computer-assisted quantification of the turbidimetric reaction between the Limulus amebocyte lysate and endotoxin. Serial dilutions of Escherichia coli endotoxin in culture-negative amniotic fluid were prepared, and the samples were run in the assay. Amniotic fluid was found to enhance the reaction, and a dilution of 1:20 was required for this biologic fluid to behave similarly to pyrogen-free water. The sensitivity of this kinetic turbidimetric technique in the detection of endotoxin in amniotic fluid was 40 pg/ml. This method was applied to the quantification of endotoxin concentration in amniotic fluid in 26 patients with intraamniotic infection and premature rupture of membranes. Patients in active labor had higher concentrations of endotoxin (median = 47,514 pg/ml) than nonlaboring patients (median = 635 pg/ml) (p less than 0.025). Therefore, women with preterm labor had a higher median concentration of endotoxin in amniotic fluid than patients who were not in labor.

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    • "Since this translational research study could have clinical implications for new BPD therapy, microarray methodology provided a screening tool for gene expression that could be important for effective and safe therapy. Fortunately, there has been previous work measuring plasma DEX levels in preterm infants being treated for BPD [19] [20] as well as measurements of endotoxin levels in amniotic fluid [18]. Therefore the present microarray studies used a clinically relevant stimulus dose of LPS (10ng/ml) with and without DEX (10 "
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    ABSTRACT: Bronchopulmonary dysplasia (BPD) is one of the most common causes of mortality and morbidity in neonatal intensive care units. Persistent inflammation, with an abnormal influx of polymorphonuclear leukocytes (PMNs) followed by monocytes (MONOs), occurs early in the pathogenesis of BPD. Anti-inflammatory therapy with better efficacy and safety than dexamethasone (DEX) is needed. In the present study we determined cell-specific gene expression and cytokine release in response to glucocorticoids versus interleukin-10 (IL-10). Subsequently, we hypothesized that the insensitivity of MONOs to DEX was associated with a failure of the glucocorticoid receptor to translocate to the nucleus. PMNs and MONOs were isolated from umbilical cord blood at birth, and pretreated with PBS vehicle, IL-10 or glucocorticoids prior to endotoxin (LPS)-stimulation for 4 and 18h. Genome-wide gene expressions were determined by microarray and validated by RT-qPCR. Interleukin 8 release in cell culture supernatant was measured by ELISA. To examine the mechanism of monocyte insensitivity to glucocorticoids, nuclear translocation of the glucocorticoid receptor was determined by Western blots. MONOs had 6 times the number of genes changing expression with IL-10 compared to PMNs at 4h. DEX at the therapeutic level for neonates with BPD had no effect on gene expression in MONOs. The order of potency for inhibition of interleukin-8 release from MONOs was IL-10 >betamethasone >dexamethasone and hydrocortisone. Glucocorticoid potency in MONOs was directly related to glucocorticoid receptor translocation to nucleus. Gene expression profiling for IL-10 versus glucocorticoids indicates there may be major differences in therapeutic efficacy for BPD.
    American Journal of Translational Research 01/2013; 5(1):103-15. · 3.23 Impact Factor
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    • "Micro-organisms can be cultured from 10–40% of AFs collected during PTL (Romero et al., 1988a, 1994; Gomez et al., 1995). In addition, LPS (Cox et al., 1988; Romero et al., 1988b) as well as an impressive array of mediators of the inflammatory response, including IL-1β (Hillier et al., 1993; Romero et al., 1992; Gomez et al., 1995), are found in a sizeable proportion of AFs that are collected during PTL. Other cytokines, e.g. "
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