Caffeine is a substance presented in foods such as coffee, tea, soft drinks, chocolates and medicines and is commonly consumed by pregnant women. Due to its ability to cross the placental membrane and accumulate in th...Caffeine is a substance presented in foods such as coffee, tea, soft drinks, chocolates and medicines and is commonly consumed by pregnant women. Due to its ability to cross the placental membrane and accumulate in the fetus body, caffeine and its metabolites have been contraindicated or recommended in small doses during pregnancy. Studies in rodents relate caffeine intake to lower rates of fertilization, embryonic implantation, changes in placental structure, increased occurrence of low fetal and placental weights, abortion and stillbirth. However, in humans, studies involving caffeine consumption are inconclusive. Methodological complexity, difficulty for measuring caffeine intake and ethical reasons are limiting factors for a more accurate conclusion. So far, caffeine recommendation ranges from 100 to 300 mg/day. Even though researches have recommended low caffeine consumption by pregnant women in order to avoid deleterious consequences during gestation, a safe dose has not been established until now. The aim of the present review is to describe the main findings on the effects of caffeine consumption during pregnancy in both human and rodent experimental models.展开更多
Objective To examine whether urocortin is produced locally to regulate utero-placental vascular tone during pregnancy.Methods We examined the distribution of urocortin in human placenta, fetal membranes and uterine ...Objective To examine whether urocortin is produced locally to regulate utero-placental vascular tone during pregnancy.Methods We examined the distribution of urocortin in human placenta, fetal membranes and uterine tissue at term in the presence and absence of labor using a urocortin antibody produced in our laboratory and the immunoperoxidase staining method. Subsequently, we tested urocortin secretion from chorio-decidual cells in vitro using an immunoblot technique. Then, we tested whether urocortin is present in maternal plasma throughout gestation using a radioimmunoassay. A Sephadex G-50 column was used to examine whether immunoreactive urocortin (IR-urocortin) in maternal plasma is the same as synthetic urocortin.Results IR-urocortin was observed in vascular smooth muscle of myometrium decidual stromal cells, syncytiotrophoblast and amnion epithelium. No differences in staining intensity for urocortin were detected between tissues obtained in the absence or presence of labor. Staining intensity for IR-urocortin was greatest in the decidua, suggesting this may be the main site of urocortin production. Positive staining for urocortin was observed in 40% of chorio-decidual cells with 34% of these cells secreting urocortin under basal conditions. Urocortin was detectable in maternal plasma from 16 weeks gestation and concentrations did not change as gestation progressed. IR-urocortin in the maternal plasma eluted from a Sephadex G-50 column at the same site as synthetic urocortin and had a calculated retention co-efficient of 0.44.Conclusion This study indicates that urocortin is produced by the decidua during human pregnancy and is detectable in maternal plasma. These data are consistent with the hypothesis that urocortin is produced locally by the decidua and may act to regulate utero-placental blood flow.展开更多
文摘Caffeine is a substance presented in foods such as coffee, tea, soft drinks, chocolates and medicines and is commonly consumed by pregnant women. Due to its ability to cross the placental membrane and accumulate in the fetus body, caffeine and its metabolites have been contraindicated or recommended in small doses during pregnancy. Studies in rodents relate caffeine intake to lower rates of fertilization, embryonic implantation, changes in placental structure, increased occurrence of low fetal and placental weights, abortion and stillbirth. However, in humans, studies involving caffeine consumption are inconclusive. Methodological complexity, difficulty for measuring caffeine intake and ethical reasons are limiting factors for a more accurate conclusion. So far, caffeine recommendation ranges from 100 to 300 mg/day. Even though researches have recommended low caffeine consumption by pregnant women in order to avoid deleterious consequences during gestation, a safe dose has not been established until now. The aim of the present review is to describe the main findings on the effects of caffeine consumption during pregnancy in both human and rodent experimental models.
文摘Objective To examine whether urocortin is produced locally to regulate utero-placental vascular tone during pregnancy.Methods We examined the distribution of urocortin in human placenta, fetal membranes and uterine tissue at term in the presence and absence of labor using a urocortin antibody produced in our laboratory and the immunoperoxidase staining method. Subsequently, we tested urocortin secretion from chorio-decidual cells in vitro using an immunoblot technique. Then, we tested whether urocortin is present in maternal plasma throughout gestation using a radioimmunoassay. A Sephadex G-50 column was used to examine whether immunoreactive urocortin (IR-urocortin) in maternal plasma is the same as synthetic urocortin.Results IR-urocortin was observed in vascular smooth muscle of myometrium decidual stromal cells, syncytiotrophoblast and amnion epithelium. No differences in staining intensity for urocortin were detected between tissues obtained in the absence or presence of labor. Staining intensity for IR-urocortin was greatest in the decidua, suggesting this may be the main site of urocortin production. Positive staining for urocortin was observed in 40% of chorio-decidual cells with 34% of these cells secreting urocortin under basal conditions. Urocortin was detectable in maternal plasma from 16 weeks gestation and concentrations did not change as gestation progressed. IR-urocortin in the maternal plasma eluted from a Sephadex G-50 column at the same site as synthetic urocortin and had a calculated retention co-efficient of 0.44.Conclusion This study indicates that urocortin is produced by the decidua during human pregnancy and is detectable in maternal plasma. These data are consistent with the hypothesis that urocortin is produced locally by the decidua and may act to regulate utero-placental blood flow.
