Amniotic Sac - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Amniotic Sac

The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform

M H Kaufman – 1st expert on this subject based on the ideXlab platform

  • studies of the mechanism of Amniotic Sac puncture induced limb abnormalities in mice
    The International Journal of Developmental Biology, 2000
    Co-Authors: M H Kaufman, H H Chang

    Abstract:

    The principal advantage of chorionic villus sampling (cvs) over amniocentesis for the determination of the genetic constitution of the embryo is that it may be undertaken earlier in pregnancy. If carried out too early in pregnancy, it has the risk of inducing craniofacial and limb abnormalities, a condition termed the oromandibulofacial limb hypogenesis (OMFL) syndrome in genetically normal infants. It is believed that the defects observed have a vascular origin, possibly due to anoxia of tissues due to fetal blood loss or thrombus formation at the site of biopsy with distal embolization. We believe that this does not adequately explain the findings from the experimental animal literature involving Amniotic Sac puncture (ASP). Based on these experimental findings, we have hypothesised that (i) the defects observed following cvs may result from the consequences of oligohydramnios following the inadvertent puncturing of the Amniotic Sac during this procedure, and (ii) that cleft palate and the postural limb defects observed (e.g., clubfoot and clubhand) are secondary to embryonic/fetal compression. Our experimental studies shed new light on the mechanism of induction of the limb defects seen, but particularly syndactyly. Evidence of hypoperfusion of the peripheral part of the developing limb bud is observed, which interferes with apoptosis that occurs in the digital interzones, or induces an abnormal degree of cellular proliferation and/or tissue regeneration in these sites, possibly because of over-expression of critical genes involved in limb pattern specification. Cleft palate, tail abnormalities and abnormalities of sternal ossification are also observed in our model.

  • Influence of anaesthetic agent on limb abnormalities observed following Amniotic Sac puncture.
    European journal of morphology, 1998
    Co-Authors: M H Kaufman, H H Chang

    Abstract:

    In all of our previous studies into the effect of Amniotic Sac puncture (ASP) carried out on day 13 of pregnancy in mice, we have used intraperitoneal Avertin (tribromoethanol) as the general anaesthetic. In the present study, we used an inhalational anaesthetic (a mixture of halothane, oxygen and nitrous oxide in a ratio of 2:3:3). The principal difference between these two regimens is that even under optimal post-operative conditions when Avertin is used it can take between 45 and 90 min before complete recovery is achieved; when the inhalational anaesthetic is used, complete recovery is usually achieved within about 3-5 min. Because the experimental conditions were otherwise identical, this allowed the influence of the anaesthetic employed during ASP and the incidence of abnormalities induced on survival rate to day 19 of pregnancy to be studied. The survival rate was slightly higher when the inhalational anaesthetic was used, as was the incidence of limb abnormalities, although the overall incidence of gross abnormalities involving the palate, limbs and tail was not significantly different. The most marked difference, however, was in the incidence of syndactyly, which was significantly lower when the inhalational compared to the intraperitoneal anaesthetic was used: 26.6% v. 70.2% of the abnormal limbs analysed. A possible hypothesis is presented to explain this difference.

  • analysis of interdigital spaces during mouse limb development at intervals following Amniotic Sac puncture
    Journal of Anatomy, 1998
    Co-Authors: H H Chang, M H Kaufman

    Abstract:

    A spectrum of limb abnormalities ranging from adactyly, syndactyly, acrosyndactyly to nail hypoplasia was encountered in mouse embryos subjected to Amniotic Sac puncture at the corresponding gestational stage when human chorionic villus sampling (cvs) would normally be performed clinically. Previous skeletal studies revealed that, apart from the occasional incidence of fusion of 2 distal phalanges, syndactyly usually only affected the soft tissues within the interdigital spaces. A similar situation was also observed in cases of adactyly; while the skeletal elements of the digits were present, the soft tissues in the interdigital spaces failed to separate. A transient period of bradycardia is induced, possibly secondary to compression of the embryo by the extraembryonic membranes and uterine muscles following Amniotic Sac puncture. These factors, we believe, produce temporary hypoxia/ischaemia of the distal extremities, and may lead to the modification of the interdigital mesenchymal tissues within the autopods. In order to investigate the mechanism(s) underlying soft tissue syndactyly, limbs recovered at 0.5, 4, 8, 12, 24, or 36 h following Amniotic Sac puncture (ASP) were examined histologically. Vascular disruption in the form of localised areas of haemorrhage, vascular dilatation and congestion and the presence of fluid-filled cavities occurred in relation to the marginal vein and vascular plexus in the interdigital spaces. It is hypothesised that this interfered with the normal equilibrium of the preset programs of mitosis/cell death and apoptosis within the mesenchymal cells of the interdigital spaces. Apoptosis in these areas was inhibited in the majority of the experimental limbs analysed 4 h after ASP. Instead of undergoing necrosis/apoptosis, increased mitotic activity was usually observed from 8 h following ASP at the sites where apoptosis would normally be expected to be seen. The aberrant fate of the interdigital mesenchyme following ASP and the underlying mechanism(s) involved are discussed, as is the critical importance of an adequate vascular supply to the interdigital spaces during the morphogenesis of the autopod. We believe that this report contributes to understanding the mechanism(s) which lead to syndactyly following ASP, and the limb defects occasionally seen following cvs when this is undertaken during early gestation.

H H Chang – 2nd expert on this subject based on the ideXlab platform

  • studies of the mechanism of Amniotic Sac puncture induced limb abnormalities in mice
    The International Journal of Developmental Biology, 2000
    Co-Authors: M H Kaufman, H H Chang

    Abstract:

    The principal advantage of chorionic villus sampling (cvs) over amniocentesis for the determination of the genetic constitution of the embryo is that it may be undertaken earlier in pregnancy. If carried out too early in pregnancy, it has the risk of inducing craniofacial and limb abnormalities, a condition termed the oromandibulofacial limb hypogenesis (OMFL) syndrome in genetically normal infants. It is believed that the defects observed have a vascular origin, possibly due to anoxia of tissues due to fetal blood loss or thrombus formation at the site of biopsy with distal embolization. We believe that this does not adequately explain the findings from the experimental animal literature involving Amniotic Sac puncture (ASP). Based on these experimental findings, we have hypothesised that (i) the defects observed following cvs may result from the consequences of oligohydramnios following the inadvertent puncturing of the Amniotic Sac during this procedure, and (ii) that cleft palate and the postural limb defects observed (e.g., clubfoot and clubhand) are secondary to embryonic/fetal compression. Our experimental studies shed new light on the mechanism of induction of the limb defects seen, but particularly syndactyly. Evidence of hypoperfusion of the peripheral part of the developing limb bud is observed, which interferes with apoptosis that occurs in the digital interzones, or induces an abnormal degree of cellular proliferation and/or tissue regeneration in these sites, possibly because of over-expression of critical genes involved in limb pattern specification. Cleft palate, tail abnormalities and abnormalities of sternal ossification are also observed in our model.

  • Influence of anaesthetic agent on limb abnormalities observed following Amniotic Sac puncture.
    European journal of morphology, 1998
    Co-Authors: M H Kaufman, H H Chang

    Abstract:

    In all of our previous studies into the effect of Amniotic Sac puncture (ASP) carried out on day 13 of pregnancy in mice, we have used intraperitoneal Avertin (tribromoethanol) as the general anaesthetic. In the present study, we used an inhalational anaesthetic (a mixture of halothane, oxygen and nitrous oxide in a ratio of 2:3:3). The principal difference between these two regimens is that even under optimal post-operative conditions when Avertin is used it can take between 45 and 90 min before complete recovery is achieved; when the inhalational anaesthetic is used, complete recovery is usually achieved within about 3-5 min. Because the experimental conditions were otherwise identical, this allowed the influence of the anaesthetic employed during ASP and the incidence of abnormalities induced on survival rate to day 19 of pregnancy to be studied. The survival rate was slightly higher when the inhalational anaesthetic was used, as was the incidence of limb abnormalities, although the overall incidence of gross abnormalities involving the palate, limbs and tail was not significantly different. The most marked difference, however, was in the incidence of syndactyly, which was significantly lower when the inhalational compared to the intraperitoneal anaesthetic was used: 26.6% v. 70.2% of the abnormal limbs analysed. A possible hypothesis is presented to explain this difference.

  • analysis of interdigital spaces during mouse limb development at intervals following Amniotic Sac puncture
    Journal of Anatomy, 1998
    Co-Authors: H H Chang, M H Kaufman

    Abstract:

    A spectrum of limb abnormalities ranging from adactyly, syndactyly, acrosyndactyly to nail hypoplasia was encountered in mouse embryos subjected to Amniotic Sac puncture at the corresponding gestational stage when human chorionic villus sampling (cvs) would normally be performed clinically. Previous skeletal studies revealed that, apart from the occasional incidence of fusion of 2 distal phalanges, syndactyly usually only affected the soft tissues within the interdigital spaces. A similar situation was also observed in cases of adactyly; while the skeletal elements of the digits were present, the soft tissues in the interdigital spaces failed to separate. A transient period of bradycardia is induced, possibly secondary to compression of the embryo by the extraembryonic membranes and uterine muscles following Amniotic Sac puncture. These factors, we believe, produce temporary hypoxia/ischaemia of the distal extremities, and may lead to the modification of the interdigital mesenchymal tissues within the autopods. In order to investigate the mechanism(s) underlying soft tissue syndactyly, limbs recovered at 0.5, 4, 8, 12, 24, or 36 h following Amniotic Sac puncture (ASP) were examined histologically. Vascular disruption in the form of localised areas of haemorrhage, vascular dilatation and congestion and the presence of fluid-filled cavities occurred in relation to the marginal vein and vascular plexus in the interdigital spaces. It is hypothesised that this interfered with the normal equilibrium of the preset programs of mitosis/cell death and apoptosis within the mesenchymal cells of the interdigital spaces. Apoptosis in these areas was inhibited in the majority of the experimental limbs analysed 4 h after ASP. Instead of undergoing necrosis/apoptosis, increased mitotic activity was usually observed from 8 h following ASP at the sites where apoptosis would normally be expected to be seen. The aberrant fate of the interdigital mesenchyme following ASP and the underlying mechanism(s) involved are discussed, as is the critical importance of an adequate vascular supply to the interdigital spaces during the morphogenesis of the autopod. We believe that this report contributes to understanding the mechanism(s) which lead to syndactyly following ASP, and the limb defects occasionally seen following cvs when this is undertaken during early gestation.

Cynthia R Long – 3rd expert on this subject based on the ideXlab platform

  • adequacy of prenatal care and risk of pre term rupture of Amniotic Sac membranes
    Acta Obstetricia et Gynecologica Scandinavica, 1993
    Co-Authors: Carol A Gosselink, Edem E Ekwo, Atef H Moawad, Robert Woolson, Cynthia R Long

    Abstract:

    Premature rupture of Amniotic membranes (PROM) is associated with perinatal morbidity and mortality. A matched case-control study was undertaken to determine whether adequacy of prenatal care was associated with increased risk for PROM. Three study groups were defined, consisting of women delivering pre term with PROM, full term with PROM, and pre term without PROM. Cases were singly matched by race, age, and parity with women having full term deliveries without PROM. Data were collected by face-to-face structured interviews with eligible subjects and by medical records abstraction. Conditional multiple logistic regression indicated that among women with inadequate levels of prenatal care during pregnancy the risk for pre term PROM was 3.11 (CI = 1.10-8.78) and for pre term without PROM 2.18 (CI= 1.05–4.53) times higher than for their matched controls, even when adjusted for other sociodemographic, behavioral, index pregnancy, and medical history factors. We conclude that inadequate prenatal care may be a…

  • Coitus late in pregnancy: risk of preterm rupture of Amniotic Sac membranes.
    American journal of obstetrics and gynecology, 1993
    Co-Authors: Edem E Ekwo, Atef H Moawad, Carol A Gosselink, Robert Woolson, Cynthia R Long

    Abstract:

    Coitus with or without orgasm in late pregnancy is inconsistently associated with preterm rupture of Amniotic Sac membranes. We tested the hypothesis that during late pregnancy sexual behaviors including sexual positioning relate to the occurrence of premature rupture of membranes.
    Women aged 15 to 45 years having preterm premature rupture of membranes, term premature rupture of membranes, or preterm delivery without premature rupture of membranes were matched singly by age, race, and parity to control women delivered of term infants. Information about six sexual activities, obstetric history, cervical infections, smoking during pregnancy, and sociodemographic information was obtained by face-to-face interview.
    Only the male superior position was significantly associated with preterm premature rupture of membranes (odds ratio 2.40, 95% confidence interval 1.16 to 4.97) and preterm delivery without premature rupture of membranes (odds ratio 1.82, confidence interval 1.02 to 3.25) after confounding variables were controlled for. No sexual positioning or sexual activities related significantly to term premature rupture of membranes.
    Most sexual positions and activities during late pregnancy are not associated with adverse pregnancy outcomes.

  • coitus late in pregnancy risk of preterm rupture of Amniotic Sac membranes
    American Journal of Obstetrics and Gynecology, 1993
    Co-Authors: Edem E Ekwo, Atef H Moawad, Carol A Gosselink, Robert Woolson, Cynthia R Long

    Abstract:

    Objectives: Coitus with or without orgasm in late pregnancy is inconsistently associated with preterm rupture of Amniotic Sac membranes. We tested the hypothesis that during late pregnancy sexual behaviors including sexual positioning relate to the occurrence of premature rupture of membranes. Study Design: Women aged 15 to 45 years having preterm premature rupture of membranes, term premature rupture of membranes, or preterm delivery without premature rupture of membranes were matched singly by age, race, and parity to control women delivered of term infants. Information about six sexual activities, obstetric history, cervical infections, smoking during pregnancy, and sociodemographic information was obtained by face-to-face interview. Results: Only the male superior position was significantly associated with preterm premature rupture of membranes (odds ratio 2.40, 95% confidence interval 1.16 to 4.97) and preterm delivery without premature rupture of membranes (odds ratio 1.82, confidence interval 1.02 to 3.25) after confounding variables were controlled for. No sexual positioning or sexual activities related significantly to term premature rupture of membranes. Conclusion: Most sexual positions and activities during late pregnancy are not associated with adverse pregnancy outcomes.