The Transport of Elemental Mercury into Fetal Tissues

Modifications of Cell Signalling in the Cytotoxicity of Metals

“…Elemental mercury has a high vapour pressure which greatly increases the risk of exposure to mercury vapour via inhalation. While the occupational exposure is still the most serious hazard, a large number of people are exposed to mercury vapour from dental amalgam fillings (Nylander et al 1987;Clarkson et al 1988). In addition, inorganic mercury is methylated in soil and bottom sediments.…”

“…Methyl mercury accumulates in fresh-water fish which therefore constitutes an important source of exposure for humans subjects. Although metallic mercury vapour is oxidized to ionic mercury after absorption, it exists in blood as a vapour long enough to cross both the blood-brain barrier (Miyamoto 1983) and the placental barrier (Clarkson et al 1972). Methyl mercury readily diffuses across these barriers and can be concentrated in both fetal and adult brain (Berlin et al 1975), whereas the passage of mercuric mercury to the brain and to the placenta is limited.…”

“…Despite several mechanistic studies using toxic metals, the toxicological relevance of metal interference with Ca2+ and Ca2+-dependent processes has often been questioned because of the relatively high metal concentrations used in these studies. We have recently investigated the effects of selected metals on cell signalling and found that, at concentrations only marginally higher than those reported in exposed subjects (Clarkson et al 1988), adverse effects occur in in vitro cell systems. In the following sections we will give a brief description of the general mechanisms involved in cell signalling and present some of our recent data on the effect of H$+ in neuroadrenergic cells.…”

Health hazard evaluation report: HETA-87-265-1975, Joseph T. Luttmer, D.D.S., Cincinnati, Ohio.

“…These symptoms generally occur gradually and may be associated with personality changes such as irritability, temper outbursts, excitability, shyness, and indecision 4,5 . Finally, there is theoretical potential for adverse reproductive effects, but these have not been documented 6,7 . The relationship between dose of mercury absorbed and physiologic response may be affected by age, sex, nutritional status and previous mercury exposure.…”

Mercury in human amniotic fluid.

“…In animal experiments methylmercury and E'lemental mercury cross the placenta freely, while inorganic mercury compounds accumulate in the placenta (2,3,7,11).…”