Amniotic cavity

Amniotic Fluid Amniotic cavity fluid which is produced by the amnion and fetal lungs and... 

In chick embryos, malformations were induced by introducing thahdomide into the amniotic cavity. However, other types of traumatic procedures similarly resulted in abnormalities (162). 

Williamson AP, Blattner RJ, Lutz HR. Abnormalities in chick embryos following thalidomide and other insoluble compounds in the amniotic cavity. Proc Soc Exp Biol Med 1963 112 1022-5. 

Amniocentesis is performed by a physician for prenatal diagnosis of congenital disorders, to assess fetal maturity, or to look for Rh isoimmunization or intrauterine infection. Although ultrasound is not essential, amniocentesis is best performed with its assistance to aid locaHzation of the placenta and to determine the presentation of the fetus. The best sites for obtaining amniotic fluid are behind the neck of the fetus, below its head, or from other unoccupied areas of the amniotic cavity. 

In the human, the concentration of reverse T3 (rT3), an iodothyronine generated from 5-deiodination of T4, in amniotic fluid (AF) far exceeds its concentration in maternal serum. Rat models of fetal hypothyroidism, maternal hypothyroidism and combined maternal-fetal hypothyroidism were enoployed to explore the source (s) of AF rT3 since it had earlier been suggested that AF rT3 concentration mi t be used as a means of diagnosing fetal hypothyroidism in utero. These studies indicated that AF rT3 content was influenced by maternal and not fetal thyroid function (Table 1) and that rT3 itself was poorly trani rted from maternal serum into the amniotic cavity. Fetal serum rT3 concentration is dependent ipon both maternal and fetal thyroid function. Suzuki et al., have also r rted that changes in rat AF rT3 concentration are mainly dependent ipon maternal thyroid function. These findings suggested to us that tissues in contact with both maternal serum and fetal serum, or maternal tissues and the... 

Espinoza J. Anitmicrobial peptides in amniotic fluid defensins, calprotectin and bacterial permeability-increasing protein in patients with microbial invasion of the amniotic cavity, intra-amniotic inflammation, preterm labor, and premature rupture of membranes. J Matem Fetal Neonatal Med 2003 13 2-21. 

Push the injection pipet through the extraembryonic tissue into the amniotic cavity (Note 15). Then push the pipet tip into the epiblast layer (Fig. 7). When labeling the endoderm, the dye is partially expelled from the tip of the micropipette and the bolus of dye is then brought into contact with the apical surface of the endodermal layer and the cells are painted by moving the dye bolus against the cell surface. Apply pressure via the de Fonbrune syringe to expel a small volume of dye into the epiblast. It is important to monitor the movement of the dye front to avoid injecting any oil into the embryo (Note 16). 

Fig. 7. Labeling of the epiblast by microinjecting Dil into the distal cap of the embryo. To inject in the midline, the embryo is held at the distal tip of the egg cylinder hy gentle suction with the holding pipet (h). The injection pipet (ip) is passed through the extraembryonic tissues of the egg cylinder. The injection pipet is brought to the site of labeling from within the pro-amniotic cavity to avoid inadvertent labeling of other embryonic germ layers. The arrow points to the tip of the labeling pipet in the epiblast layer en, primitive endoderm primitive streak. Bar = 20 pm.

Inject plasmid DNA into the amniotic cavity as in section 33,2, steps 1-20, except that the plasmid DNA solution is injected instead of carbocyanine dye. It is easier if another manipulator is used for injecting, so the injecting pipet does not interfere with the electroporation apparatus if they are set up on the same micromanipulator. 

Insert tbe grafling pipette by a sharp jabbing actiai ttuough all tissue layers into the pro-amniotic cavity at the site of transplantation. If necessary, a beveled jMpet may be used. 

Insert the injection and grafting pipet through the yolk sac then the amnion into the amniotic cavity. 

Retrovirus can also be injected into the amniotic cavity to label structures that can not be seen, but are in direct contact with the amniotic fluid, such as skin. 

The commonest congenital abnormality of the urethra is posterior urethral valves, which may result in the most severe renal disease in childhood (see also Sect. 6.2). This condition requires regular followup with imaging. Antenatal insertion of a double-J stent between the fetal bladder or dilated collecting system of the kidneys and the amniotic cavity under sonographic guidance allows decompression of the urinary tract. However, as this procedure... 

Anotlier 15a-hydroxy derivative, 15a-hydroxyestriol (cstetrol), was detected in the urine of newborns (Hagen et al., 1965). Using simultaneous injection of estradiol-HI to the mother and estradiol- C into the amniotic cavity, it was demonstrated that cstetrol (hli) ori nates principally in the fetal compartment ((lurpide et at., 1966a Schw ers el al., 1967). 

The exchange of steroid hormones between the fetus and the placenta and between the placenta and the mother is very active for both free and conjugated forms in this section we will consider the transfer system between these three compartments and also its relationship to the amniotic cavity. 

Significant ejuantities of estriol, estriol sulfate, and estriol glucuronidc are localized in the amniotic fluid (TToen et aL, 1961), and since this compartment exhibits a high sulfatase activity, it can be concluded that fetal membranes and the amniotic cavity are actively involved in the interchange of steroid conjugates between fetus and mother. 

Fig. 19. Principal pathways in tbe transfer of androgen and eatri on conji tes between the amniotic cavity, fetus, placenta, and mother. (1) Possible alternatives (2) suggested glucuronidase activity- Ei estrone Kt estradiol estriol Ei S estrone sulfate Et-S estradiol sulfate Kj-S estriol sulfate Ei-Glu estrone glucuronide Ei-Glu estradiol glucuronide Ej-Glu estriol glucuronide Ej-S,Glu estriol-3-sulfale, IbiF ucuronide DIIA dehydroepiandrosterone I60-IIO-DHA l6a-hydroxydehydro-epiandrosterone DlIA-5 dehydroepiandrosterone sulfate I6a-I10-D1IA-S 16a-hy-droxydehydroepiandrasterone sulfate.

---