Mercury redistribution with

Haemodialysis can be used when renal fimction has declined after severe mercury toxicity. As mercury redistributes itself between red blood cells and plasma, haemodialysis is more effective if L-cysteine is added as a chelating agent, since the free thiol group combines with mercury and so removes Hg ions from the system. 

Mercuric chloride is a potent nephrotoxicant in the adult rat, but has little effect on the newborn [222], There are significant maturational changes in organ, cellular and subcellular distribution of mercury during the first 4 weeks after birth. With increasing age, mercury is redistributed from the renal cytosolic fraction to the nuclear/mitochondrial fraction, where it may be more damaging. 

According to Cameron et al. [11], mercury is redistributed into all of the hydrocarbon cuts after stream cracking. They found that the most highly contaminated fractions were butyl or propyl cuts, accounting for approximately 90 to 95% of the total mercury in the distillation column. About 75% of the mercury that entered a steam cracked unit was not found in the hydrocarbon products, but, rather, contaminated the internals of the unit. Of course, this mercury, when contacted with a clean, mercury-free feedstock wiU render the product mercury-rich. On the other hand, should the raw mercury-containing feedstock or one of its contaminated cuts be transported to another site, then the transport vessel will be polluted. 

When used in therapeutic doses, dimercaprol is associated with a high incidence of adverse effects, including hypertension, tachycardia, nausea, vomiting, lacrimation, salivation, fever (particularly in children), and pain at the injection site. Its use has also been associated with thrombocytopenia and increased prothrombin time—factors that may limit intramuscular injection because of the risk of hematoma formation at the injection site. Despite its protective effects in acutely intoxicated animals, dimercaprol may redistribute arsenic and mercury to the central nervous system, and it is not advocated for treatment of chronic poisoning. Water-soluble analogs of dimercaprol—unithiol and succimer—have higher therapeutic indices and have replaced dimercaprol in many settings. 

The redistribution reaction in lead compounds is straightforward and there are no appreciable side reactions. It is normally carried out commercially in the liquid phase at substantially room temperature. However, a catalyst is required to effect the reaction with lead compounds. A number of catalysts have been patented, but the exact procedure as practiced commercially has never been revealed. Among the effective catalysts are activated alumina and other activated metal oxides, triethyllead chloride, triethyllead iodide, phosphorus trichloride, arsenic trichloride, bismuth trichloride, iron(III)chloride, zirconium(IV)-chloride, tin(IV)chloride, zinc chloride, zinc fluoride, mercury(II)chloride, boron trifluoride, aluminum chloride, aluminum bromide, dimethyl-aluminum chloride, and platinum(IV)chloride 43,70-72,79,80,97,117, 131,31s) A separate catalyst compound is not required for the exchange between R.jPb and R3PbX compounds however, this type of uncatalyzed exchange is rather slow. Again, the products are practically a random mixture. 

Methylmercury compounds undergo extensive enterohepatic recirculation therefore, introduction of a nonabsorbable mercury-binding substance into the intestinal tract should facilitate their removal from the body. A polythiol resin has been used for this purpose in humans and appears to be effective. The resin has certain advantages over penicillamine. It does not cause redistribution of mercury in the body with a subsequent increase in the concentration of mercury in blood, and it has fewer adverse effects than do sulfhydryl agents that are absorbed. Clinical experience with various treatments for methylmercury poisoning in Iraq indicates that penicillamine, N-acetylpenicillamine, and an oral nonabsorbable thiol resin all can reduce blood concentrations of mercury however, clinical improvement was not clearly related to reduction of the body burden of methylmercury. 

E. Redistribution of metals to the brain. Despite its capacity to increase survival in acutely poisoned animals, BAL has been associated with redistribution of mercury and arsenic into the brain. Avoid use in chronic elemental mercury poisoning or alkyl (eg, methyl) mercury poisoning, where the brain is a key target organ. 

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