elastin and Fetal-Membranes--Premature-Rupture

This study was directed to the measurement of the mechanical response of fetal membranes to physiologically relevant loading conditions. Characteristic mechanical parameters were determined and their relation to the microstructural constituents collagen and elastin as well as to the pyridinium cross-link concentrations analyzed. 51 samples from twelve fetal membranes were tested on a custom-built inflation device, which allows mechanical characterization within a multiaxial state of stress. Methods of nonlinear continuum mechanics were used to extract representative mechanical parameters. Established biochemical assays were applied for the determination of the collagen and elastin content. Collagen cross-link concentrations were determined by high-performance liquid chromatography measurements. The results indicate a distinct correlation between the mechanical parameters of high stretch stiffness and membrane tension at rupture and the biochemical data of collagen content and pyridinoline as well as deoxypyridinoline concentrations. No correlation was observed between the mechanical parameters and the elastin content. Moreover, the low stretch stiffness is, with a value of 105 ± 31 × 10(-3) N/ mm much higher for a biaxial state of stress compared to a uniaxial stress configuration. Determination of constitutive model equations leads to better predictive capabilities for a reduced polynomial hyperelastic model with only terms related to the second invariant, I 2, of the right Cauchy-Green deformation tensor. Relevant insights were obtained on the mechanical behavior of fetal membranes. Collagen and its cross-linking were shown to determine membrane's stiffness and strength for multiaxial stress states. Their nonlinear deformation behavior characterizes the fetal membranes as I 2 material.

Topics: Adult; Biomechanical Phenomena; Collagen; Elastin; Extraembryonic Membranes; Female; Fetal Membranes, Premature Rupture; Humans; Middle Aged; Models, Biological; Pregnancy; Pressure; Stress, Mechanical; Time Factors; Young Adult

A total of 131 anaerobes isolated from amniotic fluid with preterm premature rupture of membranes and stored were examined for elastolytic activity by the method described by Williams et al (Lett Appl Microbiol 1988;7:173-6).. Each strain was spot inoculated on a Columbia blood agar plate containing 1% solubilized elastin and incubated for 5 days under anaerobic conditions. Undigested elastin was precipitated by flooding trichloroacetic acid solution onto the plate, and a clear zone was visible as the elastolytic reaction around the spot of bacterial growth.. Ninety-three (71.0%) of 131 organisms showed a positive elastolytic reaction. Eleven of 20 strains (55.0%) of Peptostreptococcus magnus, 9 of 18 strains (50.0%) of Peptostreptococcus micros, 12 of 12 strains (100.0%) of Fusobacterium nucleatum, 15 of 28 strains (53.6%) of Bacteroides fragilis, 8 of 15 strains (53.3%) of Bacteroides thetaiotaomicron, and 38 of 38 strains (100.0%) of Prevotella bivia were elastolytic.. Anaerobic bacterial species prevalent in the normal vaginal flora that were isolated from amniotic fluid of women with preterm rupture of membranes produced elastolytic activity, plausibly inducing the destruction of host constitutive components.

Topics: Amniotic Fluid; Bacteria, Anaerobic; Bacteroides; Bacteroides fragilis; Culture Media; Elastin; Female; Fetal Membranes, Premature Rupture; Fusobacterium; Humans; Pancreatic Elastase; Peptostreptococcus; Pregnancy; Prevotella

Collagen content in preterm amnions with premature rupture of the membranes was significantly lower than that of preterm amnions without premature rupture of the membranes. Collagen types were studied through sodium dodecyl sulfate-polyacrylamide gel electrophoresis in human amnions from pregnant women with or without premature rupture of the membranes. Collagen types I, III, and V were recognized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in all samples. In samples taken from preterm patients with premature rupture of the membranes, the ratios of III/I, III/V, and III/total collagen were significantly lower than those from ones without premature rupture of the membranes. The ratios of I/V, I/total collagen, and V/total collagen showed no change in gestations with and without premature rupture of the membranes, respectively. In term samples there was no significant difference in the ratios of all collagen types between those with and those without premature rupture of the membranes. Elastins were not demonstrable in amnion with and without premature rupture of the membranes. These studies suggest that the reduction of type III collagen content in amnion is related to the cause of premature rupture of the membranes, particularly in preterm samples.

Topics: Adult; Amnion; Collagen; Elastin; Electrophoresis, Polyacrylamide Gel; Female; Fetal Membranes, Premature Rupture; Humans; Pregnancy; Solubility

Topics: alpha 1-Antitrypsin; Animals; Apgar Score; Disease Models, Animal; Elastin; Female; Fetal Hypoxia; Fetal Membranes, Premature Rupture; Gestational Age; Guinea Pigs; Haplorhini; Humans; Hyaline Membrane Disease; Infant, Newborn; Lung; Pregnancy; Pulmonary Surfactants; Respiratory Distress Syndrome, Newborn; Retrospective Studies; Sheep