No abstract

Concentrations of zinc, cobalt, selenium, rubidium, bromium, and gold have been determined by neutron activation analysis in 18 placental and 6 liver tissue samples at birth. Their respective mean concentrations +/- standard deviations (parts per million) were 58 +/- 10, 0.060 +/- 0.036, 1.90 +/- 0.41, 14.0 +/- 3.5, 26.9 +/- 14.3, and 0.31 +/- 0.14 in placenta, and 651 +/- 257, 0.156 +/- 0.077, 4.52 +/- 1.96, 9.2 +/- 3.7,11.2 +/- 4.1, and 0.12 +/- 0.06 in liver tissue. Thus, we observed that the mean concentrations of essential trace elements (zinc, cobalt, and selenium) were significantly higher in liver than in placenta, whereas the nonessential trace elements (rubidium, bromium, and gold) were found in significantly higher concentrations in placenta than in liver tissue.

Concentrations of zinc, cobalt, bromine, rubidium and gold have been determined by neutron activation analysis in 18 maternal and umbilical cord blood sera as well as in 7 healthy non-pregnant women who served as controls. The concentrations of essential trace elements (zinc and cobalt) were significantly lower while levels of non-essential trace elements were similar (bromine and rubidium) or increased (gold) in sera of pregnant as compared to sera of non-pregnant women. The mean value of zinc in the umbilical cord was 1.9 times higher than that of mothers. However, no correlation exists between the values of zinc in maternal and umbilical cord blood sera. These data support the hypothesis that zinc is actively transported from mother to fetus through the placenta.