OT: Mercury (Was: BBS software for the PDP 11)

I can't answer the cell count, but I can give a general answer on the rest. Mercury interferes with multiple enzymatic processes -- some of them permanently -- and it can be slow to metabolize (half life of approximately two months), meaning even a small dose can destroy a lot of cells. The central nervous system is at greatest risk because these enzymes frequently repair oxidative damage from metabolic processes, and nerve cells have high rates of metabolism for processing. As mentioned, mercury compounds are often far more toxic than the pure form. Dimethylmercury is especially effective because the extra methyl groups enable it to very easily enter the body and pass through cell membranes but only very slowly be eliminated from it; some metabolites can actually bind to tissues and remain. In this case, as little as 0.1mL is enough to cause severe or fatal poisoning according to the OSHA bulletins I have here because it will enter cells and accumulate there. Once it reaches the central nervous system, that's it. The NEJM article on the Wetterhahn case (read: http://www.nejm.org/doi/full/10.1056/NEJM199806043382305 ) estimates a lethal dose of the compound would be about 5mg/kg body weight. (As an aside, though, mercury-containing antiseptics such as thiomersal "Merthiolate" and merbromin can be safe and effective sterilizers in very low concentrations. They work through the oligodynamic effect. I grew up with my mother wielding the Mercurochrome whenever I'd get a cut, and I think it was unfairly removed from the market -- not due to toxicity, but because it was a generic product with no profit potential, so the pharmas wouldn't do the studies and the FDA classified it as "non-GRAS" along with a number of other orphaned compounds in 1998. It is still very common outside the US.) In the Wetterhahn case, latex and PVC gloves are also easily penetrated by the compound (including those she was wearing), affording her no protection at all when it spilled on her and was able to pass through her skin into the bloodstream. It is also possible part of her toxic dose came from vapour, although the fume hood should have reduced this. By the time her symptoms indicated that she had indeed received a toxic dose, chelation therapy would have been ineffective, as it indeed was. The estimated total dose per the NEJM article was about 1.3g of mercury, over three times the lethal amount. Don't mess with it. (MD, MPH) -- ------------------------------------ personal: http://www.cameronkaiser.com/ -- Cameron Kaiser * Floodgap Systems * www.floodgap.com * ckaiser at floodgap.com -- You are not ready! ---------------------------------------------------------