HEALTH HAZARDS OF ELECTROPLATING

Unique cyanide adduct in human serum albumin: potential as a surrogate exposure marker

Cyanide (CN = HCN + CN(-)) is a renowned poison and neurotoxicant that is prevalent throughout the environment. Despite a plethora of studies conducted over the last half century, relatively little is known of its potential to cause adverse health outcomes at sublethal exposures. CN exposure is normally determined from blood, but because CN is rapidly metabolized and cleared from this compartment (t(1/2) < 1 h), it is common for several half-lives to have passed before blood samples are drawn for analysis. This variable, coupled with a very narrow toxic index and metabolic diversity within the human population, has rendered accurate assessment of CN exposure, and consequently any predictions of possible adverse health outcomes, highly problematic. Prior studies by us showed the potential of Cys-SCN adducts within human serum albumin (HSA) to act as retrospective surrogates of CN exposure. Here, we report the discovery of a stable, SCN adduct at Cys(567) formed by the reaction of CN with the C-terminal Cys(558)Cys(567) disulfide bond of HSA. Treatment of HSA purified from human serum with base in guanidine hydrochloride releases a readily detectable, uniquely modified, C-terminal-19-mer peptide from Cys(567)-SCN moieties in all the samples examined thus far. Inclusion of a HSA-Cys(567)-S(13)C(15)N labeled internal standard permits quantitation of the Cys(567)-SCN adduct by LC-MS/MS in selective reaction monitoring (SRM) of the surrogate peptide with high sensitivity and good precision. Reaction of CN in vitro with the Cys(558)Cys(567) disulfide bond in HSA is specific, rapid, and concentration dependent within a putative, physiologically relevant range. Data from various human sera demonstrate the potential usefulness of this adduct as a biomarker of CN exposure.

Incidence of cancer in the electronics industry: using the new Swedish Cancer Environment Registry as a screening instrument

The object of this study was to assess the relative risks of cancer for a particular branch of industry by using the newly created cancer environment registry. The registry was created by a record linkage of the 1960 census to the Swedish Cancer Registry 1961-73. A cohort study was undertaken of all subjects classified in the census as working in the electronics or electrical manufacturing industry. The risks were calculated in relation to the general working population. The results showed a slightly higher total incidence of cancer (all sites) in this branch of industry than in the general working population, for men as well as for women. This was especially so for tumour sites connected with the pharynx and the respiratory system. The study also indicates that the new registry has a potential as a screening instrument.