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PubMed1995

Amnionitis and premature delivery with intact amniotic membranes involving Staphylococcus aureus. A case report.

Subclinical infection is suspected to be an important etiologic factor in the initiation of preterm labor in women with intact membranes. We present a case of acute clinical chorioamnionitis followed by preterm labor and fetal distress in a woman with intact membranes. The bacteriologic data on the mother and neonate clearly identified coagulase-positive Staphylococcus aureus as the etiologic factor.

Adult↗
PubMed1996

Persistent foetal tachycardia as an early marker of chorion-amnionitis. Description of a clinical case.

Intra-amniotic infection (IAI) is uncommon in pregnancy (0.5-1%) and is rarely responsible for maternal mortality, but it does lead to a high rate of maternal and foetal morbidity, e.g. sepsis, septic shock, post-partum endometritis and neonatal sepsis. The diagnosis of IAI is immediate in the case of premature rupture of the membranes, whereas it is far more difficult to reach a correct and timely diagnosis when the amniotic sac is intact, as the mother's clinical symptoms are often scarce and non-specific. Foetal and maternal prognosis in IAI depends on the timely implementation of antibiotic treatment and induction of delivery in order to drain off the infected amniotic fluid. The clinical case described here not only illustrates the difficulty in diagnosing IAI, but also confirms that timely antibiotic therapy can prevent the onset of severe maternal and foetal complications.

Adult↗
PubMed1997

[Futile intra-amnion Rivanol administration and prostaglandin labor induction in uterus unicornis unicollis with a noncommunicating right-sided horn].

We report on the futile use of labour-inducing agents in a patient with a Mullerian duct abnormality. In the 20th week of gestation, foetal death had been diagnosed in the rudimentary right horn. It is suggested that induction as well as continuation of effective contractions depends on the intact uterus (cervix, lower uterine segment, and corpus).

Abortion, Therapeutic↗
PubMed1984

Human amniotic membrane and prostaglandin biosynthesis.

The human amnion has become a significant tissue for metabolism of chemical substances with biologic activities, such as steroid hormones and prostaglandins. In this paper our studies on the biosynthesis of prostaglandins in human amnion focused on the role of prostaglandins in initiating and maintaining labor. First of all, the source of prostaglandins released in amniotic fluid was investigated. The amnion was demonstrated to possess the highest activity of generating prostaglandins among amnion, chorion laeve, and decidua vera, obtained after normal vaginal delivery. Subsequently, the bioconversion of arachidonic acid into prostaglandins and related compounds using the homogenate of human amnion was carried out without the addition of cofactors in the incubation mixture to show the natural spectrum of various types of PGs formed. PGE2 was revealed to be a main product of the amnion; its conversion rate was 5% of incubated radioactivity. Other compounds catalyzed by cyclooxygenase were PGF2 alpha (0.2%), TXB2 (0.3%), and HHT (1-2%), whereas 15-HETE (2-3%) and a mixture of 9, 11, 12-HETE (1-2%) were formed by lipoxygenase in the amnion. And third, the activity to produce PGE2 in the amnion obtained at normal vaginal delivery was greater than that obtained at cesarean section prior to the onset of labor. Thus, these results suggested that the amnion played a significant role in prostaglandin biosynthesis in uterine tissues. To provide a better understanding of the metabolism of arachidonic acid in the amnion as regards initiation and maintenance of labor, we discuss prostaglandin biosynthesis in the amnion and the mechanism of arachidonic acid release.

Amnion↗
PubMed2005

Comparison of amniotic and intramembranous unidirectional permeabilities in late-gestation sheep.

OBJECTIVE: Amniotic fluid volume is regulated by the intrinsic modulation of intramembranous absorption. However, neither the mechanisms nor the rate-limiting barriers of this transport are known. We tested the hypothesis that the amnion is the rate-limiting barrier of intramembranous absorption by comparing unidirectional permeabilities of the amnion in vitro and the intramembranous pathway in vivo. STUDY DESIGN: Unidirectional permeabilities to 99m technetium pertechnate or [14 C]inulin of fresh ovine amnion were measured in vitro in a Ussing chamber; the permeability-surface area products were calculated by the multiplication of the permeabilities by gestational age-specific amniotic surface areas. Unidirectional permeabilities of the intramembranous pathway of the 2 tracers were calculated from solute fluxes between amniotic fluid and fetal blood in chronically catheterized late-gestation fetal sheep. Statistical comparisons included t -tests, least squares regression, analysis of variance, and analysis of covariance. RESULTS: In the isolated amnion in vitro, the ratio of permeabilities in the amniotic fluid to chorionic direction and the reverse direction was not significantly different from unity for 99m technetium pertechnate (1.03+/-0.10 [SE]; n=7) or [14 C]inulin (1.10+/-0.17; n=7). In contrast, in the in vivo preparation, the ratio of intramembranous permeabilities outward from the amniotic fluid and the reverse direction was greater than unity for 99m technetium pertechnate (2.10+/-0.34; n=8; P=.014) and [14 C]inulin (4.68+/-1.24; n=7; P=.025). The permeability-surface area product of 99m technetium pertechnate (2.18+/-0.79 mL/min) of the isolated amnion was similar to the in vivo intramembranous permeability (n=8) in the amniotic fluid to fetal blood direction (1.42+/-0.34 mL/min) and greater than that in the reverse direction (0.84+/-0.25 mL/min; P=.046). The permeability-surface area product of [14 C]inulin of the amnion (0.53+/-0.20 mL/min) was similar to intramembranous permeability (n=7) in the amniotic fluid to fetal blood (0.68+/-0.15 mL/min) direction and greater than that in the reverse direction (0.22+/-0.06 mL/min; P=.0097). CONCLUSION: Solute transport across the ovine amnion depends on solute size and appears to be limited only by the amnion's passive diffusional properties. In vivo intramembranous transport similarly depends on solute size but is not exclusively a passive diffusional process because it is primarily unidirectional outward from the amniotic fluid. Although it is a major barrier, the amnion is not the only barrier and does not appear to be responsible for the unidirectional nature of intramembranous absorption. Thus, unidirectionality appears to be imparted by nonpassive mechanisms in non-amnion tissues, which most likely includes vesicular transport within the endothelial cells of the intramembranous microvessels.

Absorption↗
PubMedDate not supplied

Cross-linking of human amniotic membrane by glutaraldehyde.

PURPOSE: The transplantation of cryopreserved human amniotic membrane has been introduced recently for the reconstruction of the ocular surface. However, in some diseases the transplant usually dissolves rather quickly and early detachment may occur. Therefore, we tried to stabilize the amniotic transplant by applying glutaraldehyde for collagen cross-linking of the membrane. METHODS: 18 human amnions were prepared. 4 x 4 cm pieces of amnion were treated with 0.1% glutaraldehyde solution for 30 min. Biomechanical force-elongation measurements were performed and resistance to enzymatic digestion by 0.1% collagenase solution was tested and compared to cryopreserved and untreated fresh amnion. 8 patients with various ocular surface defects were treated with cross-linked amnion and compared to 5 patients with cryopreserved amnion. RESULTS: The force of the amnion cross-linked with glutaraldehyde at 2.5 mm elongation was increased statistically significant by 175% versus fresh amnion and 76.8% versus the cryopreserved amnion. Glutaraldehyde-treated membranes were virtually completely resistant to enzymatic digestion, while fresh and cryopreserved amnions were dissolved completely by day 7. In patients, the cross-linked membrane was preserved for up to 90 days without any signs of dissolution of the membrane and good transparency. CONCLUSIONS: Collagen cross-linking using glutaraldehyde leads to a significant increase in the biomechanical strength and enzymatic resistance of amnion, better transparency and less wrinkling. The cross-linked membrane does not dissolve for months and is well suited for the surface reconstruction of the cornea.

Amnion↗
PubMed1998

Parathyroid hormone-related protein (PTHrP) mRNA splicing and parathyroid hormone/PTHrP receptor mRNA expression in human placenta and fetal membranes.

During human pregnancy, parathyroid hormone-related protein (PTHrP) and parathyroid hormone (PTH)/PTHrP receptor are produced by the uterus, placenta, fetal membranes (amnion and chorion) and developing fetus. PTHrP alternative 3' mRNA splicing results in transcripts which encode three PTHrP isoforms and have been identified in amnion. Uteroplacental PTHrP expression is greatest in amnion and increases dramatically during late pregnancy. The aims of this study were to determine PTH/PTHrP receptor mRNA expression at preterm and term gestations and to determine 3' alternative splicing patterns in placenta, amnion and choriodecidua at preterm and term gestations. Using semiquantitative reverse transcription-polymerase chain reaction, PTHrP and PTH/PTHrP receptor transcripts were identified in preterm (n=5) and term (n=7) gestational tissues. PTH/PTHrP receptor mRNA expression did not differ between tissue types or change with advancing gestation. In contrast, PTHrP expression in the same tissues increased with advancing gestation and was significantly greater in amnion than in placenta and choriodecidua. Thus PTHrP, although produced predominantly in amnion, may act in amnion and other tissues including placenta, choriodecidua and myometrium. In amnion over placenta, transcripts encoding PTHrP 1-139 and 1-173 were detected in some preterm and all term samples and those encoding PTHrP 1-141 were detected in all samples. Similar results were obtained for reflected amnion. In placenta and choriodecidua, PTHrP 1-139 and 1-173 transcripts were undetectable or of low abundance. PTHrP 1-141 transcripts were detected in some placenta and choriodecidua samples. In summary, transcripts encoding PTHrP 1-141 appeared to be more abundantly expressed than those encoding PTHrP 1-139 or 1-173. However, the up-regulation of PTHrP expression in amnion at term may involve each of the alternative 3' mRNA splicing pathways since transcripts for each isoform appeared to be more consistently expressed at term.

Alternative Splicing↗
PubMed1993

Inhibin and activin in human fetal membranes: evidence for a local effect on prostaglandin release.

Trophoblast and fetal membranes (amnion and chorion) are the tissues forming the anatomical/functional interface between the mother and the fetus. The aim of the present study was to evaluate the presence and a possible effect of inhibin and activin in human amnion and chorion. The expression of inhibin/activin alpha, beta A, and beta B subunit messenger RNA (mRNA) and the localization of immunoreactive material were evaluated in amnion and chorion collected at term pregnancy by a Northern blot analysis and by immunohistochemistry. Amnion cells expressed the mRNA of the three inhibin/activin subunits, with the beta B message the most abundantly expressed. The epithelial layer of the amnion showed an intense fluorescent staining of beta B inhibin/activin subunit, and positive signals were also observed for the alpha and beta A subunits. Inhibin/activin alpha and beta A subunit mRNAs were found highly expressed in chorion. The cytotrophoblast of the chorion showed a positive staining for the three inhibin/activin subunit antisera. The addition of activin A increased the release of prostaglandin E2 from human amnion-derived cultured cells. The effect was dose and time dependent. Inhibin A did not induce significant changes of prostaglandin E2 release from amnion cells. The present results show that amnion and chorion produce inhibin and activin subunits and that activin stimulates the release of prostaglandin E2 from cultured amnion cells, suggesting a possible role of inhibin and activin in fetal membranes.

Activins↗
PubMed1977

[Unusual cases of maternal death caused by amniotic fluid embolism].

Five cases of amnion fluid embolism are reported. In the first case the cause of the death was the obstruction of the lung-vessels. In the lung tissue calcium embolia could also been detected. In the second case embolization started--at unruptured amnionsac--with ecclampsia-like convulsions, later it was followed by coagulopathia. In the third case amnion fluid embolism was complicated by coagulopathia. In the fourth case in addition to amnion fluid embolism endometritis purulenta complicated by endotoxinaemia and coagulopathia were also present. In all four cases rupture of the uterus was revealed. In the fifth case amnion fluid embolism developed without the rupture of the uterus. At the autopsy of cases of maternal death the possibility of amnion fluid embolism should always be considered. Although macroscopic changes seen at amnion fluid embolism are not pathognomic, when clinical and pathological symptoms of haemorrhagic diathesis are present, there always arises the suspicion of amnion fluid embolism. Since lungs are relatively resistant to putrefaction amnion fluid embolism in optimal cases can be diagnosed histologically even in exhumated lung specimen. Reliable diagnosis of amnion fluid embolism in cases of sudden maternal death gives possibility to exclude medical negligence.

Adult↗
PubMed1981

Premature labor. I. Prostaglandin precursors in human placental membranes.

Amnion and chorion from premature and term placentas after both spontaneous labor and elective cesarean section were assayed for phospholipids and fatty acid composition by 2-dimensional thin-layer chromatography and gas-liquid chromatography. In preterm placental phospholipids, phosphorus concentrations were higher in amnion than in chorion, whereas at term the membranes were similar owing to an increase in phospholipid concentration in the chorion late in gestation. PHosphatidylcholine (PC) accounted for 47% of the total phospholipid phosphorus, followed by sphingomyelin at 20%, phosphatidylethanolamine (PE) at 15%, phosphatidylserine (PS) at 12%, and phosphatidylinositol (PI) at 5%. These percentages were similar for amnion and chorion and they did not change during gestation. The percentage of arachidonic acid (AA) was higher in PS (40 to 65%) than in PE (30 to 53%) and PC (10 to 13%). The percentage of AA was significantly higher in PC, PE, and PS from the amnion in premature pregnancies than in those of the premature chorion. At term, these amnionic and chorionic phospholipids had similar concentrations of AA owing to a significant increase in AA in the chorion late in gestation. Amnionic PE from term and preterm elective cesarean section had a significantly higher percentage of AA than that from preterm and term labor. These data suggest that AA is consumed during labor and that amnionic phospholipids, particularly PE, may be its principal source. The amnion seems to be more important for the storage of AA than the chorion, particularly in preterm pregnancies in which the concentrations of phospholipids and the percentages of AA in PC, PE, and PS were significantly higher than in the chorion.

Amnion↗
PubMed1994

[Intrauterine defensive mechanism of amniotic fluid and fetal membranes].

To determine the intrauterine defensive role of urinary trypsin inhibitor (UTI), we studied the effects of UTI in amniotic fluid, fetal membranes and myometrium. The level of UTI was 94 +/- 34 U/ml in neonatal urine (compared to adult urine 8.0 +/- 6.0 U/ml) and 88 +/- 37 U/ml in amniotic fluid. This may indicate that the main source of UTI in the amniotic fluid is the fetal urine. UTI was found to be concentrated in vernix, fetal intestine, amniotic membranes and uterine myometrium. Immunostaining of term amnion revealed a dark staining for UTI, whereas in premature deliveries UTI staining was markedly decreased. In myometrium, the concentration of UTI was found to be increased during pregnancy compared to non pregnant myometrium. Also, placentas were well stained for UTI in term pregnancy. Thus UTI has an important role in amniotic fluid, fetal membranes, placenta and uterine muscles. UTI has an inhibitory effect on several enzymes and cytokines. UTI was found to inhibit neutrophil elastase activity as well as trypsin activity. Its inhibitory activity was increased in the presence of lipid. LPS stimulated amnion cells trapped more UTI than unstimulated amnion cells. UTI in amnion cells was released after addition of 1% meconium solution. UTI was also found to inhibit the effect of IL-1, TNF and interleukin-8 on amnion. These results indicate that UTI localized in amnion is important in the protection of fetal membrane especially against bacterial infections and cytokines. It is known that endothelin (ET), prostaglandin F2 alpha (PGF2 alpha) and oxytocin can induce uterine contraction. UTI could inhibit uterine contractions stimulated by ET, PGF2 alpha and oxytocin in isometric contraction test. UTI could also inhibit cervical maturation induced by interleukin-8. Therefore UTI is essential for maintenance of pregnancy. From the isometric contraction tests, we assumed that UTI might works through regulation of calcium entry or availability in the cells. Initial increase in intracellular calcium was also inhibited by UTI pre incubation dose dependantly. We examined the change in intracellular calcium at single cell level by digital image analysis with Fura 2AM as a calcium probe. At resting level UTI incubation did not produce any significant changes in intracellular free calcium. Thrombin, LPS, interleukin-8 and ET-1, known calcium agonists could increase intracellular calcium in fibroblasts, amnion and uterine myocytes. Whereas as the same doses of those known calcium agonists could not change the intracellular free Ca2+ concentrations in UTI pre incubated fibroblasts, amnion cells and uterine smooth muscle cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Abortion, Threatened↗
PubMed1997

Production of prostaglandin F2 alpha and E2 in explants of intrauterine tissues of guinea pigs during late pregnancy and labor.

Prostaglandin production in amnion and decidua is considered important for human parturition. We investigated in pregnant guinea pigs, a species similar to women in regard to the endocrinology of pregnancy, whether the production rates of PGE2 and PGF2 alpha in various intrauterine tissues are compatible with a role in parturition. Net production rates were measured at 45, 55 and 65 days of gestation and during labor in amnion, chorion, myo-endometrium, the outer layer of the myometrium, the site of placental implantation, and placenta. Net production rates in amnion increased between 45 days and labor (30-fold for PGE2 and 8-fold for PGF2 alpha, P < 0.0001). During labor, the production rates in amnion of PGE2 (P = 0.006) and PGF2 alpha (P = 0.019) were higher than at 45, 55, and 65 days of gestation. In myo-endometrium, the production rates of PGF2 alpha were higher at 65 days of gestation than at 55 days and during labor (P = 0.046). Addition of arachidonic acid (10(-5) M) increased production of PGE2 and/or PGF2 alpha in all tissues (P < 0.05) except placenta. In amnion, the response to arachidonic acid increased with advancing gestation. This suggests that 1) PGE2 and PGF2 alpha produced by amnion have a potential role in the initiation and maintenance of labor, 2) PGF2 alpha produced by myo-endometrium has a potential role in the initiation of labor, 3) cyclooxygenase(s) are not rate-limiting except in placenta, and 4) the expression of cyclooxygenase in amnion increases with advancing gestation.

Amnion↗
PubMed1997

Endothelin receptor mRNAs in human fetal membranes, chorionic vessels, and decidua parietalis.

Endothelin-1 (ET-1) is synthesized in avascular human amnion; and, immunoreactive ET-1 is present in amniotic fluid in concentrations 10 to 100 times those in blood. ET-1 acts, most commonly, in a local or paracrine manner; therefore, it is possible that amnion/amniotic fluid ET-1 acts on contiguous tissues, namely chorion laeve or placental surface (chorionic) vessels, or in an autocrine fashion on amnion cells. To address these possibilities, the levels of ET(A) and ET(B) receptor mRNAs were evaluated in amnion, chorion laeve, decidua parietalis, placenta, and chorionic vessel tissues. By Northern analysis of total RNA (20 microg), ET(A) and ET(B) receptor mRNAs were detected in decidua (n = 18), placenta (n = 14), and chorionic vessels (n = 13). In chorion laeve (n = 24), ET(B) receptor mRNA but not ET(A) receptor mRNA was detected by Northern analysis of total RNA. Northern analysis of chorion laeve poly(A)+ mRNA (1.5-2.5 microg) revealed ET(A) receptor mRNA at low levels. Neither ET(A) nor ET(B) receptor mRNAs were detected in amnion tissue by Northern analysis of total RNA (n = 30; placental and reflected amnion from 15 pregnancies) or by Northern analysis of poly(A)+ mRNA (1.5-2.5 microg). Moreover, there was no demonstrable dose-dependent effect of ET-1 on prostaglandin E2 production or DNA synthesis in amnion epithelial cells in primary culture. The findings of this investigation are indicative that ET-1 in amniotic fluid or secreted from amnion may act in a paracrine fashion on chorion laeve by way of the ET(B) receptor and on chorionic vessels by way of ET(A) and ET(B) receptors.

Amnion↗
PubMedDate not supplied

Increased apoptosis of human fetal membranes in rupture of the membranes and chorioamnionitis.

Apoptosis is thought to participate pathophysiologically in the rupture of human fetal membranes (ROM). The aim of this study was to assess apoptosis of the amnion and the chorion in relation to ROM and chorioamnionitis (CAM). The amnion and chorion at the position of the cervical os and fundus of the uterus were obtained from 44 patients. Apoptotic DNA fragmentation was densitometrically determined, and the relative ratio was used for the quantitative evaluation. Among patients without CAM, the relative ratios of apoptosis in the amnion from patients with ROM were higher than those in patients without ROM (P< 0.05). Among patients without ROM, the apoptotic levels in the amnion from patients with CAM were higher than those in patients without CAM (P< 0.05). These were the cases with the amnion at the position of cervical os and fundus, but not with the chorion. The highest ratio of apoptosis was seen in the amnion from patients with CAM and ROM. Among patients with ROM and no CAM, the apoptotic levels at the cervical os in the amnion (P=0.059) and chorion (P< 0.05) was higher than those at the fundus. The increased apoptosis of human fetal membranes was related to ROM and CAM. Apoptosis plays a role in the pathophysiology of ROM.

Adult↗
PubMed1997

Differential expression of type II, IV and cytosolic PLA2 messenger RNA in human intrauterine tissues at term.

The involvement of phospholipase A2 (PLA2) enzymes in the formation of biologically-active phospholipid metabolites by human gestational tissues has principally been characterized by the use of enzyme activity assays. While such assays have established the presence of functional PLA2 activity, there is a paucity of information concerning the tissue distribution and relative contribution to net activity made by specific PLA2 isozymes. In particular, both secretory and cytosolic isozymes may be involved in gestational tissue phospholipid metabolism. Thus, the aim of this study was to test the hypothesis that phospholipase A2 mRNA transcripts encoding Type II, Type IV and cytosolic PLA2 are tissue-specifically expressed in human amnion, choriodecidua and placenta obtained at term. The relative expression of polyA+ mRNA encoding these PLA2 isozymes was determined by Northern blot analysis and laser densitometry. The data obtained confirm the tissue-specific expression of PLA2 mRNA in human intrauterine tissues. Cytosolic PLA2 mRNA was most abundantly expressed in amnion when compared to either choriodecidua (which was 5-fold less than amnion; P < 0.001) or placenta (72-fold less than amnion; P < 0.001). In contrast, the secretory PLA2 mRNA transcripts (i.e. Type II and Type IV) were most abundantly expressed in placenta. Type II PLA2 mRNA expression in choriodecidua and amnion was 30-fold less than that observed in placenta (both P < 0.001). Type IV PLA2 mRNA expression was 37-fold (P < 0.001) and 73-fold (P < 0.001) less in choriodecidua and amnion respectively. These data support the conclusion that cytosolic PLA2 is the principal PLA2 isozyme mediating phospholipid metabolism and the liberation of fatty acid substrate (i.e. arachidonic acid) in term amnion, while secretory PLA2 isozymes, and in particular, Type II PLA2 play a major role in phospholipid metabolism in term placenta.

Amnion↗