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PubMed2000

Myofibroblast differentiation in the connective tissues of the amnion and chorion of term human fetal membranes-implications for fetal membrane rupture and labour.

An area of the fetal membranes, within the rupture tear after spontaneous delivery at term, exhibits altered morphology compared to more distal sites. It is characterized by marked swelling of the amniotic and chorionic connective tissue layers, consistent with structural weakness, and a marked reduction of the thickness of both the cytotrophoblast and decidual layers. These features, albeit less extreme, have been identified in fetal membranes in the lower uterine pole in patients prior to labour. In this study of pre-labour, labour-affected and post-labour term fetal membranes, we report that these regions are associated with an alteration in the phenotype of the vimentin positive mesenchymal cell population of the chorionic connective tissue reticular layer, and are consistent with myofibroblastic differentiation, i.e. alpha-smooth muscle actin (alpha-sma) expression. In the reticular layer of the lower uterine pole biopsies in the labour-affected group the numbers and densities of alpha-sma immunoreactive positive cells were 17-fold (P=0.04) and 8.5-fold (P=0.02) higher than in mid-zone biopsies. After delivery, in rupture line biopsies the numbers and densities were 50-fold (P=0. 002) and 36-fold (P=0.003) higher compared to mid zone biopsies. The percentage of the vimentin positive population positive for alpha-sma was 2-5 per cent in mid-zone biopsies compared to 49 per cent (P=0.03) in the labour-affected 'cervical' biopsies and 69 per cent (P=0.05) in the rupture line biopsies. Within the tear sites, alpha-sma positive cells were also detected within the fibroblastic layer of the amniotic connective tissue. Although there was no significant difference between the numbers and density of alpha-sma cells in the reticular layers between mid and lower uterine pole biopsies in the pre-labour group, in a proportion of patients the biopsies were similar to labour-affected biopsies indicating that this alteration occurs prior to clinically apparent labour in these patients. The incidence of alpha-sma positive cells in the reticular layer correlated with morphological changes within the fetal membranes, for example thickness of reticular (r(2)=0.349, P=0.0006) and amniotic connective tissue layers (r(2)=0.389, P=0.0002). This suggests that cellular activities associated with myofibroblastic differentiation in the reticular layer of the chorion may be associated with the observed connective tissue changes, fetal membrane rupture and labour.

Actins↗
PubMed1993

[Diagnosis of rupture of fetal membranes: comparison of vaginal detection of fetal fibronectin and intra-amnion injection of indigo carmine].

Amniotic fluid contains a heavily glycosylated pregnancy-related isoform of fibronectin (fFN), which can be detected using FDC-6, a monoclonal antibody directed against a novel epitope specific to fFN. It has been identified in the amniotic fluid in various concentrations throughout the different pregnancy periods and is localised at the interface of the chorion and the uterine decidua. Because of the unique pregnancy-associated expression of fFN, we determined the utility of cervicovaginal appearance of fFN as a marker of membrane integrity or rupture of membranes. In a prospective study we compared 1) the detection of fFN in cervicovaginal samples by a membrane-immunoassay (ROM-Check, Mast Diagnostica, Reinfeld, FRG) with 2) the results of intraamniotic injection of Indigo Carmine (IC), followed by the observation of dye spill into the vagina to confirm rupture of membranes. 65 patients were examined, 12 patients had to be excluded from the study for various reasons. Examination results were identical in 50 patients, while in three cases the fFN results were positive with a simultaneous negative result of the intraamniotic dye injection. In the case of blood contamination, the fFN test results were not valid; testing of maternal blood and of urine samples was fFN negative in all cases. We conclude, that oncofoetal fibronectin is an excellent marker for rupture of membranes. The test is easy to perform and does not involve the risk of an intraamniotic injection of dye.(ABSTRACT TRUNCATED AT 250 WORDS)

Amnion↗
PubMed1993

[Management of mono-amnion twin pregnancy].

There have been only a few reports on monoamniotic twin pregnancies from the period of modern perinatology. Consequently, available recommendations about the management of these high-risk pregnancies are uncertain. In this study, we present the management and the outcome of three monoamniotic twin pregnancies and two further pregnancies with acardiac acephalus twin in comparison to other case reports and case series from the literature. Practical ways of caring for these high-risk pregnancies are outlined, emphasising the continuous search for entanglement of umbilical cord by ultrasound and cardiotocography. The special importance of intensified cardiotocographic monitoring is demonstrated.

Adult↗
PubMed1988

[Surgical technic of cesarean section. A preparatory cesarean section method primarily for saving the amnion].

A new technique of Caesarean delivery which makes adequate room for safe and gentle extraction of the infant and prevents injury to the foetus and the uterus is presented. The method consists of careful, layer by layer dissection in the lower uterine segment while keeping - whenever possible - the amniotic membranes intact. The opening can be made as large as needed. In a second step, the amniotic sac, now in full view, is carefully opened and the foetus safely extracted. In the ideal case, the lower part of the still intact amniotic sac containing the presenting part of the infant can be lifted out in front of the incision. There the membranes are opened and the foetus delivered. Bleeding is minimal and injury to the foetus and uterus is almost impossible. The wound can be closed with a single-layer suture, which promotes rapid healing and eliminates the danger of rupture during subsequent pregnancies. Further investigations will be necessary to prove whether this technique - lower cervical transverse Caesarean section with late amniotomy - will be worthy of becoming a standard procedure.

Adult↗
PubMed1967

The time of synthesis and the conservation of mitosis-related proteins in cultured human amnion cells.

p-Fluorophenylalanine (PFPA), an analogue of phenylalanine which may be incorporated into proteins, increases the duration of mitosis. In the present experiments, based upon quantitative analyses of time-lapse cinemicrographic films, brief treatments of cells with PFPA are shown to affect the duration of metaphase in only those cells which enter division during or shortly after treatment. The offspring of cells with prolonged metaphases also tend to have prolonged metaphases. Analyses of the kinetics of the appearance of prolonged metaphases indicate that some protein specifically associated with mitosis is synthesized primarily during a period which corresponds closely to G(2). The manner in which the defect is passed on to daughter cells indicates that the protein involved is conserved and reutilized by daughter cells for their subsequent divisions. Comparable experiments performed with low concentrations of puromycin indicate that the major effect of PFPA is due to its incorporation into protein rather than its ability to inhibit protein synthesis. The fact that puromycin-induced effects can also be passed on to daughter cells is interpreted to mean that cells make only specific amounts of some mitosis-associated proteins and that if a cell "inherits" a deficiency in such protein it is not able to compensate for the deficiency.

Amnion↗