Blood fetal

Ductus arteriosus The structure that shunts fetal blood flow away from the undeveloped fetal lungs. 

Hayashi M. 1983. Lead toxicity in the pregnant rat 11. Effects of low-level lead on delta-aminolevulinic acid dehydratase activity in maternal and fetal blood or tissue. Ind Health 21 127-135. 

Restriction analysis can be used to detect sickle cell disease prenatally, since the DNA of all cells, including amniotic cells, carries the mutant DNA. It is much more difficult to obtain fetal blood for the analysis of the mutant hemoglobin A P-chain. Furthermore, fetal blood is composed mostly of fetal hemoglobin, sinee-hemoglobin A is made later in development. 

A similar adaptive mutation is found in human fetal hemoglobin. This has a lower oxygen affinity than the adult in the absence of phosphate, but it also has a lower affinity for DPG, due mainly to the replacement His H21(143)/3 — Ser. As a result, the oxygen affinity of fetal blood exceeds that of the adult, which helps the transfer of oxygen from the maternal to the fetal circulation across the placenta (5). 

Heptachlor epoxide was measured in a strip of skin, fat, and subcutaneous tissue from 68 children who died in the perinatal period and ranged from not detected (nondetectable) to 0.563 ppm (mean 0.173) (Zavon et al. 1969). In 10 other stillborn infants, heptachlor epoxide levels measured in various tissues were as follows brain (nondetectable), lung (0.17 0.07 ppm), adipose (0.32 0.10 ppm), spleen (0.35 0.08 ppm), liver (0.68 0.50 ppm), kidney (0.70 0.28 ppm), adrenal (0.73 0.27 ppm), and heart (0.80 0.30 ppm) (Curley et al. 1969). In another study, the following heptachlor epoxide levels were measured in extracted lipids from mothers and newborn infants maternal adipose tissue (0.28 0.31 ppm), maternal blood (0.28 0.46 ppm), uterine muscle (0.49 0.51 ppm), fetal blood (1.00 0.95 ppm), placenta (0.50 0.40 ppm), and amniotic fluid (0.67 1.16 ppm) (Polishuk et al. 1977a). These data provide evidence of transplacental transfer to the fetus. 

M9. McFarlane, H., and Udeozo, I. 0. K., Immunochemical estimation of some proteins in Nigerian paired maternal fetal blood. Arch. Dis. Childhood 43, 42-46 (1968). 

Distribution - Calcium is rapidly incorporated into skeletal tissue. Normal serum calcium concentrations range from 9 to 10.4 mg/dL (4.5 to 5.2 mEq/L), but only ionized calcium is active. Calcium crosses the placenta and reaches higher concentrations in fetal blood than maternal blood. Calcium also is distributed in milk. 

Maternal PKU occurs when a pregnant woman with uncontrolled PKU has high levels of Phe in her blood, leading to elevated levels of Phe in fetal blood and consequent neurologic damage, including microcephaly and mental retardation. 

In pregnant rats not exposed to nickel, maternal and fetal blood concentrations of nickel were 3.8 and 10.6 pg/L, respectively (Szakmary et al. 1995). Twenty-four hours after a single gavage dose of 5.4,... 

In addition to all of the adverse effects and contraindications previously described for morphine, the following contraindications apply specifically to these drugs. They are contraindicated in pregnant women because of their potential teratogenic effects. They also can cause respiratory depression in the mother, which reduces oxygenation of fetal blood, and in the newborn the incidence of sudden infant death syndrome (SIDS) in the newborn is also increased. 

Placental transfer of local anesthetics is known to occur rapidly, fetal blood concentrations generally reflecting those found in the mother. However, the quantity of drug crossing to the fetus is also related to the... 

Blood can be taken from fetuses at necropsy by cardiac puncture before fetal examination. It is also possible to take, from satellite litters, fetal blood or amniotic fluid during gestation (i.e., day 19 of gestation). The fetal blood is pooled by litter to obtain a sufficient plasma volume for analyzes. 

The placenta is an extremely permeable membrane which separates the fetal blood supply from the maternal blood supply. Normally it allows for the exhange of gases, nutrients and metabolites between mother and child. It... 

The placenta, through which the drugs will pass to the embryo or fetus, will vary in structure at different times in gestation and between species. For example, there may be six layers of cells between maternal and fetal blood in some species (e.g., pig), but in humans,... 

The protein level in the embryonic or fetal bloodstream is also lower and different from that in the maternal circulation, and so the effect on the concentration gradient may well be less. So the concentration of drug in the embryonic or fetal blood may be lower than that in the maternal blood. 

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