B. R. Hicks

Specific production of prostaglandin E by human amnion in vitro

Abstract Prostaglandin production by intra-uterine human tissues has been investigated using a method of tissue superfusion. Tissues were obtained at elective Caesarean section and after spontaneous vaginal delivery. It was found that all the tissues studied (amnion, chorion, decidua and placenta) produced more prostaglandin E (PGE) and 13,14-dihydro-15-keto-prostaglandin F (PGFM — the major circulating metabolite of prostaglandin F) than prostaglandin F (PGF). Amnion produced significantly more PGE (but not PGF or PGFM) than any other tissue. Prostaglandin production by each tissue was similar whether it was taken at elective Caesarean section or after spontaneous vaginal delivery.

Possible role for prostacyclin in human parturition

Human amnion, chorion, decidua and placenta produced 6-oxo-PGF1alpha when superfused in vitro. Furthermore amnion, an avascular tissue, produced more 6-oxo-PGF1alpha after labour than all other tissues investigated and its production of 6-oxo-PGF1alpha was significantly greater after labour than before the onset of labour. These findings suggest that prostacyclin production by foetal membranes may have a role in the mechanisms controlling human parturition. Moreover, this is the first evidence for the production of prostacyclin by an avascular tissue.

INCREASE OF THE PROSTAGLANDIN PRECURSOR, ARACHIDONIC ACID, IN AMNIOTIC FLUID DURING SPONTANEOUS LABOUR

Concentrations of free arachidonic acid have been measured by gas liquid chromatography in amniotic fluid obtained during spontaneous labour at term. Levels of arachidonic acid ranged from 0·14 to 2·2 μg/ml and increased significantly (P<0·01) with advancing cervical dilatation. Concentrations of arachidonic acid showed no significant relation to concentrations of either prostaglandin F or 13,14‐dihydro‐15‐keto‐prostaglandin F. These findings are discussed with respect to the role of arachidonic acid in the control of prostaglandin biosynthesis during human parturition.

Localization of anti-endometrial antibody binding in women with endometriosis using a double-labelling immunohistochemical method.

Summary. Anti‐endometrial antibody binding was localized using a double‐labelling immunohistochemical method on frozen sections of endometrium taken from a woman without pelvic disease. Serum from 40 women with endometriosis was tested and, as controls, serum samples from 20 adult males and 20 umbilical cords. The method allowed compensation for endogenous immunoglobulins in endometrium and accurate localization of anti‐endometrial antibody binding in the cytoplasm of the glandular epithelium. Significantly more women with endometriosis (14/40) were found to have anti‐endometrial antibodies than controls (1/40) (P< 0.001; χ2). There was no correlation between disease severity and the presence of anti‐endometrial antibodies or the intensity of staining.

PROSTAGLANDIN DEHYDROGENASE IN THE PLACENTA BEFORE AND AFTER THE ONSET OF LABOUR

Inactivation of prostaglandins in the placenta was studied using an assay for 15‐hydroxy‐prostaglandin dehydrogenase (PGDH). Forty‐four patients with normal single pregnancies between 38 and 42 weeks gestation were studied. Placentae were obtained before the onset of labour in 9, after spontaneous labour in 18, and after oxytocin‐induced labour in 17 cases, PGDH‐activity ranged from 54 to 495 nanomoles PGF2α/g placenta/minute, with a mean±SEM of 207 ±18 nanomoles/g/minute. The results indicate that the PGDH content of the human placenta does not change markedly with the onset or during the process of labour. The length of either spontaneous or oxytocin‐induced labour was not influenced by the PGDH content of the placenta.

In vitro culture of endometrial stromal and gland cells as a model for endometriosis: The effect of peritoneal fluid on proliferation

OBJECTIVE To test the hypothesis that the cell-free fraction of PF from women with endometriosis affects the proliferation of endometrial epithelial and stromal cells in vitro. DESIGN A cell biologic and immunohistochemical study. SETTING University teaching hospital. PATIENT(S) Premenopausal women undergoing laparoscopy and women with histologically normal endometrium undergoing hysterectomy were selected. INTERVENTION(S) Peritoneal fluid (PF) and serum were collected at laparoscopy. Endometrial epithelial and stromal cells were obtained by enzymic dissociation of tissue, and epithelium was separated from stromal cells by sieving. Epithelial and stromal cell populations were purified by removal of contaminating cells using Thy-1-and CD-45-labeled immunomagnetic beads. Isolated endometrial gland and stromal cells were cultured in the presence of PF or serum from women with and without endometriosis. MAIN OUTCOME MEASURE(S) Cell proliferation was assessed by measurement of incorporation of 3[H]thymidine after 48 hours in culture. RESULT(S) Isolated endometrial gland and stromal cells were able to proliferate in vitro. The proliferative effect of PF or sera from women with endometriosis did not differ significantly from normal controls. CONCLUSION(S) We conclude that PF from women with endometriosis does not have an additional mitogenic effect compared with women without endometriosis. It may be postulated that the endometrium from women with endometriosis responds differently to the effects of PF.

Prostaglandin metabolism in placenta and chorion before and after the onset of labor

Abstract Prostaglandin metabolism was studied in placenta and chorion obtained at term before the onset of labor, after spontaneous labor and after oxytocin-induced labor. Incubated with 500 ng PGF 2α per gram tissue and without added co-factors, placenta metabolized 269 ± 19 ng PGF 2α (mean ± SE, n = 18) and chorion 215 ± 21 ng PGF 2α (mean ± SE, n = 18) within 60 min. Inter-patient variations in the amount of PGF 2α metabolized and in the percentage of PGF 2α recovered under the form of its 15-keto- or its 13,14-dihydro-15-keto-metabolite, related neither to the onset nor to the cause of labor. The observations suggest that prostaglandin metabolism in placenta and chorion does not markedly decrease with the onset and during the process of labor.

Effect of relaxin on prostaglandin E production by human amnion: changes in relation to the onset of labour

Summary. The effect of relaxin on prostaglandin E (PGE) production by human amnion in vitro was investigated. When amniotic discs were incubated in the presence of increasing concentrations of relaxin, two distinct effects were observed. Discs prepared from women delivered by caesarean section before the onset of labour showed a significant decrease in PGE output at relaxin concentrations of 0.5–2 μg/ml; the effect was abolished at higher relaxin concentrations. Discs obtained from women delivered after labour of spontaneous onset responded to the addition of relaxin (4–8 μg/ml) with a significant increase in PGE output, although this increase was only evident in patients in whom labour had started with intact membranes. These results suggest that relaxin, which is present in decidua and chorion laeve at term, may have a paracrine effect on the amnion, inhibiting PGE production during continuing pregnancy but favouring its production during spontaneous labour.

SPECIFIC PRODUCTION OF PROSTAGLANDIN E BY HUMAN AMNION IN VITRO

Prostaglandin production by intra-uterine human tissues has been investigated using a method of tissue superfusion. Tissues were obtained at elective Caesarean section and after spontaneous vaginal delivery. It was found that all the tissues studied (amnion, chorion, decidua and placenta) produced more prostaglandin E (PGE) and 13,14-dihydro-15-keto-prostaglandin F (PGFM - the major circulating metabolite of prostaglandin F) than prostaglandin F (PGF). Amnion produced significantly more PGE (but not PGF or PGFM) than any other tissue. Prostaglandin production by each tissue was similar whether it was taken at elective Caesarean section or after spontaneous vaginal delivery.