Mercury cellular mechanisms

Impregnation Process. In both processes the first step in the impregnation of wood is carried out by evacuating the air from the wood vessels and cell lumens (27). Any type of mechanical vacuum pump is adequate if it can reduce the pressure in the apparatus to 750 mm of mercury or less. Some industrial producers only reduce the pressure to about 711 mm of mercury. Experience has shown that the air in the cellular structure of most woods is removed as fast as the pressure in the evacuation vessel is reduced. Pumping for 30 min at 1 mm pressure is sufficient to remove the air. The vacuum pump is isolated from the system at this point. 

Toxic effects of phenylmercuric acetate are correlated with its rapid metabolic breakdown into the mercuric ion. Generally, mercury interferes with cellular enzymatic mechanisms by combining with sulfhydryl (-SH) groups of different enzymes and thereby produces nonspecific cell injury or death. 

Ethacrynic acid (Table 10-11) is a powerful loop diuretic whose molecular mechanism of action is not fully clear. However, it has marked pharmacodynamic similarities to the mercurial diuretics such as merbaphen (see above) and mersalyl, both of which are also phenoxyacetic acid derivatives, as well as in vitro and in vivo comparability in its reaction with SH groups It competes with them for the same receptors. It is not surprising that an analogy, if not identity, of mechanism of action at the cellular level has been proposed. Equation 10.5, which illustrates a Michael-type addition, might represent a possible enzyme inactivation. 

I. Mechanism of toxicity. Mercury reacts with sulfhydryl (SH) groups, resulting in enzyme inhibition and pathologic alteration of cellular membranes. 

Oehme FW (1978) Mechanisms of heavy metal inorganic toxicides. In Oehme (ed) Toxicity of heavy metals in the environment. Dekker, New York, pp 69-85 Orion Research Inc (1970) Mercury by electrode. Orion Newslett 11 41-42 Ortiz DF, Kreppel L, Speiser DM, Scheel G, McDonald G, Ow DW (1992) Heavy metal tolerance in the fission yeast requires an ATP-binding cassette-type vacuolar membrane transporter. EMBO J 11 3491-3499 Percival SS, Harris ED (1990) Copper transport ceruloplasmin characterization of the cellular uptake mechanism. Am J Physiol 258 C140-C146 Philipson KD (1985) Sodium-caldum exchange in plasma membrane vesicles. Annu Rev Physiol 47 561-571... 

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