Maternal Age and Contractility of Human Myometrium in Pregnancy
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Myometrium
Contractility
Uterine contraction
Uterine contraction pressures were quantified (in Montetevideo units) in 109 women at term gestation who received oxytocin for induction or augmentation of labor and whose labor resulted in a spontaneous vaginal delivery. Newborn five-minute Apgar scores were greater than or equal to 8 in 108 of the 109 neonates, and no immediate neonatal morbidity was attributable to the oxytocin stimulation of labor. Women undergoing oxytocin induction had significantly greater uterine contraction pressures than those with oxytocin augmentation. During oxytocin induction 91% of women achieved at least 200 to 224 Montevideo Units and 40% at least 300 Montevideo units versus 77 and 7.7%, respectively, during augmentation of labor. With concurrent fetal monitoring these levels of uterine activity should be sought before consideration of a cesarean delivery because of presumed cephalopelvic disproportion or failure to progress.
Uterine contraction
Labor Induction
Cephalopelvic disproportion
Apgar score
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Myometrium
Uterine contraction
Corticotropin-releasing hormone
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Myometrium
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Uterine contraction
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In this paper, we applied a new theoretical model of uterine contraction to a large panel of human pregnant and nonpregnant myometrial strips, treated or not by corticotrophin-releasing hormone (CRH). This model is based on a fine analysis of the contraction curves. This analysis yielded four mathematical parameters (beta, theta, tau 1, and tau 2) related to excitability, duration of plateau phase, and time constants for relaxation describing, respectively, the different portions of the contraction cycle. This leads to specific differences in spontaneous contractile activity between pregnant and nonpregnant states. The relaxing effect of CRH in the pregnant state is presumably correlated with the origin of the strips (the lower uterine segment). Besides our observation of a specific receptor-dependent relaxing effect of CRH in both pregnant and nonpregnant myometrium, we could identify highly significant effects at given CRH concentration for beta in nonpregnant myometrium and for theta, tau 1, and tau 2 in pregnant myometrium. In addition, highly significant differences were found between pregnant and nonpregnant myometrium. Also, we discovered a strong correlation between theta and tau 1, specifically in the pregnant state. Although the biochemical signification of these results remains to be elucidated, they contribute to emphasize the complex network of CRH action at the myometrial level. Furthermore, our approach could pave the way toward a better analysis of the efficacy of the uterine contractile behavior.
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Myometrium
Uterine contraction
Contractility
Involution (esoterism)
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The effect of instenon upon the uterine contractile activity was studied in pregnant rats. The drug administration at a dose resulted in significant suppression of the myometrium contractility. The effect was not decreased when instenon was injected against the background of oxytocin. On the other hand, the concurrent injection of oxytocin upon a single or long-term administration of instenon produced a pronounced stimulating action on the myometrium contractility.
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Contractility
Uterine contraction
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Myometrium
Oxytocin receptor
Tocolytic agent
Uterotonic
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Aim To establish and optimize the dysmenorrhea model of oxytocin induced in vitro uterine contraction in mice. Methods Several kinds of estrogen used to enhance the sensibility of mouse uterus were compared, the uterus was separated from the body, 0.5~10 U·L-1 oxytocin was used to induce uterine contraction, the variations after changing treatment were observed, and four parameters used to described the uterine contraction were compared. Results Oxytocin in the concentration of 5 U·L-1 was the suitable dose; the contractions were constant 5~30 min after oxytocin was given; the sensibility of uterus showed a little decrease but was not significant when body weight increased; the contractions were stable 5~30 min after oxytocin was given; the activity of uterus was completely suppressed by 1 mg·L-1 verapamil, 100 μg·L-1 nifedipine and 250 μg·L-1 chloropromazine. Conclusion Oxytocin induced in vitromouse uterine contraction model was a convenient, quick and stable in vitro dysmenorrhea model, suitable for screening dysmenorrhea therapy drugs.
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The electrical activity of the cervix can be measured during labour. The influence of oxytocin on electromyographic (EMG) activity of the cervical musculature was studied in 80 primiparous women after induction of labor. The highest electrical activity registered at the time of uterine contraction and between two contractions was used for analysis. The basic pattern of oxytocin-produced changes in muscular contractions in the cervix observed via EMG activity is that of the activity increasing with contractions of the uterine corpus and diminishing between contractions. The effect of oxytocin on cervical musculature is different in ripe and unripe cervices.
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Cervical dilatation
Labor Induction
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In brief Various etiologies can cause uterine myometrium contraction, which leads to preterm birth. This study demonstrates a new functional relationship between the Ras-related C3 botulinum toxin substrate 1 (RAC1) and uterine myometrium contraction in preterm birth. Abstract Preterm birth (PTB) is a public health issue. The World Health Organization has recommended the use of tocolytic treatment to inhibit preterm labour and improve pregnancy outcomes. Intrauterine inflammation is associated with preterm birth. RAC1 can modulate inflammation in different experimental settings. In the current study, we explored whether RAC1 can modulate spontaneous uterine myometrium contraction in a mouse model of lipopolysaccharide (LPS)-induced intrauterine inflammation. Subsequently, we recorded uterine myometrium contraction and examined uterine Rac1 expression in a mouse model of preterm birth and a case in pregnant women by Western blotting analysis. We also measured progesterone levels in the blood serum of mice. Murine myometrium was obtained 12 h post LPS treatment. Human myometrium was obtained at the time of caesarean section. We found that in the LPS-treated group of mice, uterine myometrium contraction was enhanced, protein levels and activation of RAC1 were increased and serum progesterone levels were decreased. The protein levels of RAC1 were also increased in preterm birth and in pregnant women. NSC23766, a RAC1 inhibitor, attenuated uterine myometrium contraction and diminished RAC1 activation and COX-2 expression. Furthermore, silencing of RAC1 suppressed cell contraction and COX-2 expression in vitro . In conclusion, our results suggested that RAC1 may play an important role in modulating uterine myometrium contraction. Consequently, intervening with RAC1 represents a novel strategy for the treatment of preterm birth.
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