Transplacental passage

The constant regions of the immunoglobulin molecules, particularly the C 2 and 0 3 (and C 4 of IgM and IgE), which constitute the Fc fragment, are responsible for the class-specific effector functions of the different immunoglobulin molecules (Table 50-7, bottom part), eg, complement fixation or transplacental passage. 

It involves the transfer into the recipient of preformed antibody, i.e. there is no antigenic stimulus. This can occur (a) naturally, by transplacental passage of antibody... 

Smrek AL, Adams SR, Liddle JA, et al. 1978. Pharmacokinetics of mirex in goats 2. Residue tissue levels, transplacental passage during recovery. J Agric Food Chem 26(4) 945-947. 

P-gp outlined above are potential pathways that can be exploited to improve or prevent the transplacental passage of drugs. It should be noted that most of these pathways involve a complex interplay of several factors that may vary in a cell- or tissue-specific manner and hence their contribution to placental P-gp should be explored. 

C. Marzolini, C. Rudin, L.A. Decosterd, A. Telenti, A. Schreyer, J. Biollaz, and T. Buclin. Transplacental passage of protease inhibitors at delivery. Aids. 16 889-893 (2002). 

Antithyroid agent Bioavailability (%) Protein binding (%) Transplacental passage Breast milk levels (M P)2 Half-life (h)... 

Plasminogen is inherited as two codominant autosomal alleles. Fetal synthesis and the absence of transplacental passage have been demonstrated. In newborns there is a decrease in both plasma plasminogen concentration, and functional plasminogen activity, suggestive of a fetal dysfunctional plasminogen molecule. Several hereditary dysfunctional molecules have been described in adults with recurrent thromboembolic disease. The defects in these molecules include abnormal active sites, impaired activator binding, and defective activation. 

The transplacental passage of maternal iodothyronines is quantitatively modest, although it might be sufficient to ensure adequate fetal development. Maternal thyroid hormone secretion is markedly increased during pregnancy (by 25-50%) thyroid therapy should therefore be carefully adjusted during pregnancy (58). 

Brandt, I., L. Dencker and Y. Larsson, "Transplacental Passage and Embryonic-Fetal Accumulation of Hexachlorophene in Mice, Toxicol. Appl. Pharmacol. 49, 393-401 (June,... 

Anane R, Bonini M, Creppy EE. 1997. Transplacental passage of aluminum from pregnant mice to fetus organs after maternal transcutaneous exposure. Hum Exp Toxicol 16 501-504. 

Marzolini C, Rudin C, Decosterd LA, Telenti A, Schreyer A, Biollaz J, Buclin T. Swiss mother-child HIV cohort study. Transplacental passage of protease inhibitors at delivery. AIDS 2002 16 889-93. 

Renal tubular acidosis occurred in a preterm boy shortly after birth (23). His mother had taken oral acetazolamide during pregnancy for glaucoma. When renal tubular acidosis developed, acetazolamide was detected in his serum, demonstrating transplacental passage of acetazolamide. 

Waysbort A, Giroux M, Mansat V, Teixeira M, Dumas JC, Fuel J. Experimental study of transplacental passage of alpha interferon by two assay techniques. Antimicrob Agents Chemother 1993 37(6) 1232-7. 

At clinical doses, transplacental passage of suxamethonium is insufficient to produce paralysis of the neonate. 

The transplacental passage of maternal iodothyronines is quantitatively modest, although it might be sufficient to... 

Transplacental passage of nitrite occurred in pregnant rats given doses of 2.5-50 mg kg orally. 

Mil. Migeon, C. J., Bertrand, J., and Gemzell, C. A., The transplacental passage of various steroid hormones in mid-pregnancy. Recent Progr. Hormone Res. 17, 207-248 (1961). 

Onoda K, Hasegawa A, Sunouchi M, et al. 1978. Studies on the fate of poisonous metals in experimental animal (VII) Distribution and transplacental passage of manganese in pregnant rat and fetus. J Pood Hyg Soc 19 208-215. 

Transplacental passage of activity was evident a few minutes after maternal injection after 2.5 h, fetal plasma activity was in equilibrium with maternal plasma, showing 4.3% of the maternal plasma concentration, totally as free " Tc-pertechnetate. However, the total plasma content in the fetus never exceeded 0.15% of the maternal administered activity. Urine immediately obtained after birth showed high concentrations of free Tc-pertechnetate. Passage of " Tc-HSA across the placenta is minimal (Herbert et al. 1969). 

Thyrotoxicosis occurs in about 0.2% of pregnancies and is caused most frequently by Graves disease. Antithyroid drugs are the treatment of choice radioactive iodine is clearly contraindicated. Historically, propylthiouracil has been preferred over methimazole because transplacental passage was thought to be lower however, both propylthiouracil and methimazole cross the placenta equally. Current data suggest that either may be used safely in the... 

A correlation has been reported between lead levels in maternal blood and in the placenta (Schramel et al. 1988). Placental levels were higher in occupationally lead-exposed women than in non-exposed ones. There is a transplacental passage of lead to the fetus, both in animal experiments and in humans (Mayer-Popken et al. 1986). In animal experiments, the growing organism accumulated more lead in the CNS than did the adult animal (Momcilovic and Kos-tial 1974). Blood-lead levels in the child at birth are associated with those in the mother. Concentrations in the child appear to be somewhat lower than in the mother, in whole blood as well as in red blood cells and plasma (Cavalleri etal. 1978). There is usually a decrease in B-Pb at the start of pregnancy, but this is probably mainly due to an expansion of the plasma volume. 

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