The Effects ofEscherichia coliSTa (Heat Stable) Toxinon the Contractility of Isolated Human MyometriumIn Vitro

[摘要] Objective:The purpose of the study was to assess the effects ofEscherichia coliSTa (heat stable)toxin on isolated human myometrial response to oxytocin.Methods:One hundred and sixteen muscle strips were obtained from the lower uterine segmentof 42 women undergoing cesarean section at term. Amniotic membranes and decidua were excluded.Uterine contractility in response to cumulative doses ofE. coliSTa toxin was recorded, aswell as uterine response to cumulative doses of oxytocin before and after incubation with STa toxinor vehicle. The 50th percentile effective oxytocin concentration (EC50) of muscle strips with andwithout spontaneous activity before and after the incubation with STa toxin or vehicle was calculated.A pairedttest was used for comparison.Results:Muscle strips with and without spontaneous activity responded to cumulative doses ofoxytocin before and after the incubation with STa toxin or vehicle. No differences in contractionforce, duration, or frequency were noted between the groups (P> 0.05). Furthermore, this toxinwas not able to induce uterine contractility when tested alone.Conclusions:The inability of this toxin to affect myometrial response to oxytocin in this study maybe due to the absence of amnion cells, chorion, or decidua. Other possible explanations for the lackof response are discussed.

[学科分类] 妇产科学