Production of prostaglandin f2alpha and its metabolite by endometrium and yolk sac placenta in late gestation in the tammar wallaby, Macropus Eugenii.
In this study, we investigated production of prostaglandin (PG) F2alpha and its metabolite, PGFM, by uterine tissues from tammar wallabies in late pregnancy. Endometrial explants were prepared from gravid and nongravid uteri of tammars between Day 18 of gestation (primitive streak) and Day 26.5 (term) and were incubated in Ham's F-10 medium supplemented with glutamine and antibiotics for 20 h. PGF2alpha and PGFM in the medium were assayed by specific, validated RIAs. Control tissues (leg muscle) did not produce detectable amounts of either PG. Both gravid and nongravid endometria secreted PGF2alpha, and production increased significantly in both gravid and nongravid uteri towards term. PGFM was produced in small amounts by both gravid and nongravid uteri, and the rate of production did not increase. Neither oxytocin nor dexamethasone stimulated PG production in vitro in any tissue at any stage. Thus, the surge in peripheral plasma PGFM levels seen at parturition may arise from increased uterine PG production, but further study is needed to define what triggers this release. (+info)
Expression of trophinin, tastin, and bystin by trophoblast and endometrial cells in human placenta.
Trophinin, tastin, and bystin comprise a complex mediating a unique homophilic cell adhesion between trophoblast and endometrial epithelial cells at their respective apical cell surfaces. In this study, we prepared mouse monoclonal antibodies specific to each of these molecules. The expression of these molecules in the human placenta was examined immunohistochemically using the antibodies. In placenta from the 6th week of pregnancy, trophinin and bystin were found in the cytoplasm of the syncytiotrophoblast in the chorionic villi, and in endometrial decidual cells at the utero placental interface. Tastin was exclusively present on the apical side of the syncytiotrophoblast. Tissue sections were also examined by in situ hybridization using RNA probes specific to each of these molecules. This analysis showed that trophoblast and endometrial epithelial cells at the utero placental interface express trophinin, tastin, and bystin. In wk 10 placenta, trophinin and bystin were found in the intravillous cytotrophoblast, while tastin was not found in the villi. After wk 10, levels of all three proteins decreased and then disappeared from placental villi. (+info)
Delay of preterm delivery in sheep by omega-3 long-chain polyunsaturates.
A positive correlation has been shown between dietary intake of long-chain omega-3 fatty acids in late pregnancy and gestation length in pregnant women and experimental animals. To determine whether omega-3 fatty acids have an effect on preterm labor in sheep, a fish oil concentrate emulsion was continuously infused to six pregnant ewes from 124 days gestational age. At 125 days, betamethasone was administered to the fetus to produce preterm labor. Both the onset of labor and the time of delivery were delayed by the fish oil emulsion. Two of the omega-3-infused ewes reverted from contractions to nonlabor, an effect never previously observed for experimental glucocorticoid-induced preterm labor in sheep. Maternal plasma estradiol and maternal and fetal prostaglandin E2 rose in control ewes but not in those infused with omega-3 fatty acid. The ability of omega-3 fatty acids to delay premature delivery in sheep indicates their possible use as tocolytics in humans. Premature labor is the major cause of neonatal death and long-term disability, and these studies present information that may lead to a novel therapeutic regimen for the prevention of preterm delivery in human pregnancy. (+info)
Luteinizing hormone inhibits conversion of pregnenolone to progesterone in luteal cells from rats on day 19 of pregnancy.
We have previously reported that intrabursal ovarian administration of LH at the end of pregnancy in rats induces a decrease in luteal progesterone (P4) synthesis and an increase in P4 metabolism. However, whether this local luteolytic effect of LH is exerted directly on luteal cells or on other structures, such as follicular or stromal cells, to modify luteal function is unknown. The aim of the present study was to determine the effect of LH on isolated luteal cells obtained on Day 19 of pregnancy. Incubation of luteal cells with 1, 10, 100, or 1000 ng/ml of ovine LH (oLH) for 6 h did not modify basal P4 production. The addition to the culture medium of 22(R)-hydroxycholesterol (22R-HC, 10 microgram/ml), a membrane-permeable P4 precursor, or pregnenolone (10(-2) microM) induced a significant increase in P4 accumulation in the medium in relation to the control value. When luteal cells were preincubated for 2 h with oLH, a significant (p < 0.01) reduction in the 22R-HC- or pregnenolone-stimulated P4 accumulation was observed. Incubation of luteal cells with dibutyryl cAMP (1 mM, a cAMP analogue) plus isobutylmethylxanthine (1 mM, a phosphodiesterase inhibitor) also inhibited pregnenolone-stimulated P4 accumulation. Incubation with an inositol triphosphate synthesis inhibitor, neomycin (1 mM), or an inhibitor of intracellular Ca2+ mobilization, (8,9-N, N-diethylamino)octyl-3,4,5-trimethoxybenzoate (1 mM), did not prevent the decrease in pregnenolone-stimulated P4 secretion induced by oLH. It was concluded that the luteolytic action of LH in late pregnancy is due, at least in part, to a direct action on the luteal cells and that an increase in intracellular cAMP level might mediate this effect. (+info)
Outcome of pregnancy in women with congenital shunt lesions.
OBJECTIVE: To evaluate the outcome of pregnancy in women with congenital shunt lesions. SETTING: Retrospective study in a tertiary care centre. METHODS: Pregnancy history was obtained by a standardised questionnaire and medical records were reviewed. PATIENTS: 175 women were identified, at a mean (SD) age of 42 (14) years. Pregnancies occurred in 126 women: 50 with an atrial septal defect, 22 with a ventricular septal defect, 22 with an atrioventricular septal defect, 19 with tetralogy of Fallot, and 13 with other complex shunt lesions. RESULTS: 309 pregnancies were reported by 126 woman (2.5 (1.6) pregnancies per woman). The shortening fraction of the systemic ventricle was 40 (8)%, and 98% were in New York Heart Association class I-II at last follow up. Spontaneous abortions occurred in 17% of pregnancies (abortion rate, 0.4 (0.9) per woman). Gestational age of the 241 newborn infants was 8.8 (0.8) months. There were no maternal deaths related to pregnancy. Pre-eclampsia and embolic events were observed in 1.3% and 0.6%, respectively of all pregnancies. Women with complex shunt lesions more often underwent caesarean section (70% v 15-30%, p = 0.005) and gave birth to smaller babies for equivalent gestation (2577 (671) g v 3016 (572) to 3207 (610) g, p < 0.05). The recurrence risk of congenital heart disease was 2.5%. CONCLUSIONS: The outcome of pregnancy is favourable in women with congenital shunt lesions if their functional class and their systolic ventricular function are good. Such patients can be reassured. (+info)
Expression of neurotrophins and their receptors in human bone marrow.
The expression of neurotrophins and their receptors, the low-affinity nerve growth factor receptor (p75LNGFR) and the Trk receptors (TrkA, TrkB, and TrkC), was investigated in human bone marrow from 16 weeks fetal age to adulthood. Using reverse transcription-polymerase chain reaction, all transcripts encoding for catalytic and truncated human TrkB or TrkC receptors were detected together with trkAI transcripts, whereas trkAII transcripts were found only in control nerve tissues. Transcripts for the homologue of the rat truncated TrkC(ic113) receptor were identified for the first time in human tissue. Stromal adventitial reticular cells were found immunoreactive for all neutrophin receptors. In contrast, hematopoietic cell types were not immunoreactive for p75LNGFR but showed immunoreactivity for one or several Trk receptors. TrkA immunoreactivity was found in immature erythroblasts. Catalytic TrkB immunoreactivity was observed in eosinophilic metamyelocytes and polymorphonuclear cells. Truncated TrkB immunoreactivity was found in erythroblasts and megacaryocytes. Immunoreactivity for both catalytic and truncated TrkC receptor was observed in promyelocytes, myelocytes, some polymorphonuclear cells and megacaryocytes. Neutrophin transcript levels appeared higher at fetal than at adult stages, no variation in Trk family transcript levels was observed. The local expression of neurotrophin genes suggests a wide range of paracrine and/or autocrine mode of action through their corresponding receptors within the bone marrow. (+info)
Maternal adrenocortical hormones maintain the early development of pancreatic B cells in the fetal rat.
To investigate the effect of maternal adrenocortical hormones on the development of fetal pancreatic islet cells, pregnant rats were adrenalectomised on d 6 of gestation. On d 12-16 the growth patterns of fetal insulin-producing B cells, glucagon-producing A cells, and somatostatin-producing D cells were observed histometrically. Maternal adrenalectomy resulted in growth retardation of fetal B cells on d 12-15. Maternal corticosterone therapy prevented this retardation. Maternal adrenalectomy, however, did not affect the developmental patterns of A and D cells. By Western blotting and immunohistochemistry, glucocorticoid receptors were demonstrated to be present in the islet cells from d 12 to d 15. These results suggest that maternal adrenocortical hormones, glucocorticoids in particular, maintain the early development of fetal pancreatic B cells through their specific intracellular glucocorticoid receptor. (+info)
Developmental changes in mucosubstances revealed by immunostaining with antimucus monoclonal antibodies and lectin staining in the epithelium lining the segment from gizzard to duodenum of the chick embryo.
The mucosubstances in the epithelium lining the segment from gizzard to duodenum during development of the chick embryo was studied histochemically using monoclonal antibodies against gizzard mucus and lectins, with attention to the regional differentiation of the epithelium in this segment. The anterior limit of epithelial CdxA mRNA expression detected by in situ hybridisation, which served as the position of the gizzard-duodenal boundary, was clearly found from d 3. Granules positive for some antibodies or lectins were found in the region ranging from the posterior part of the gizzard to the duodenum at d 3, which was followed by an increase in the number of granules and a gradual enlargement of the granule-positive area to the anterior part of the gizzard over 4-6 d. From d 4, the epithelia of the gizzard body and of the pyloric or duodenal region came to be differently stained with some antibodies or lectins. From d 10, each region showed a specific pattern of staining. The epithelia of the gizzard body and pyloric region contained abundant mucus granules with a different staining pattern. In the duodenum the number of stained granules was low except in occasional goblet cells. Thus the epithelia of the gizzard body, pyloric region and duodenum may produce different mucosubstances and the regional differentiation in these epithelia may start at rather early stages soon after the formation of digestive tube. (+info)