title: The chemical nature of mercury in human brain following poisoning or environmental exposure.
abstract: Methylmercury is among the most potentially toxic species to which human populations are exposed, both at high levels through poisonings and at lower levels through consumption of fish and other seafood. However, the molecular mechanisms of methylmercury toxicity in humans remain poorly understood. We used synchrotron X-ray absorption spectroscopy (XAS) to study mercury chemical forms in human brain tissue. Individuals poisoned with high levels of methylmercury species showed elevated cortical selenium with significant proportions of nanoparticulate mercuric selenide plus some inorganic mercury and methylmercury bound to organic sulfur. Individuals with a lifetime of high fish consumption showed much lower levels of mercuric selenide and methylmercury cysteineate. Mercury exposure did not perturb organic selenium levels. These results elucidate a key detoxification pathway in the central nervous system and provide new insights into the appropriate methods for biological monitoring.
authors: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
authors: Malgorzata
authors: M
authors: Korbas
authors: John L
authors: JL
authors: O'Donoghue
authors: Gene E
authors: GE
authors: Watson
authors: Ingrid J
authors: IJ
authors: Pickering
authors: Satya P
authors: SP
authors: Singh
authors: Gary J
authors: GJ
authors: Myers
authors: Thomas W
authors: TW
authors: Clarkson
authors: Graham N
authors: GN
authors: George
mesh_terms: D015502:Absorptiometry, Photon; D000062:Accidents, Occupational; D000368:Aged; D000818:Animals; D001923:Brain Chemistry; D002648:Child; D003545:Cysteine / Q000031:analogs & derivatives / Q000032:analysis; D004781:Environmental Exposure; D004785:Environmental Pollutants / Q000493:pharmacokinetics / Q000506:poisoning*; D005260:Female; D005399:Fishes; D005506:Food Contamination; D006801:Humans; D008658:Inactivation, Metabolic; D008297:Male; D008460:Meat / Q000032:analysis; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D017669:Mercury Compounds / Q000032:analysis; D020262:Mercury Poisoning, Nervous System / Q000378:metabolism* / Q000473:pathology; D008767:Methylmercury Compounds / Q000032:analysis / Q000493:pharmacokinetics / Q000506:poisoning*; D008875:Middle Aged; D008958:Models, Molecular; D015394:Molecular Structure; D053758:Nanoparticles; D009518:New York; D061848:Optical Imaging; D012643:Selenium / Q000032:analysis; D018036:Selenium Compounds / Q000032:analysis; D012750:Seychelles; D013552:Swine
chemical_list: D004785:Environmental Pollutants; D017669:Mercury Compounds; D008767:Methylmercury Compounds; D018036:Selenium Compounds; C030589:methylmercury cysteine; C032901:mercury-selenium complex; D008628:Mercury; D012643:Selenium; D003545:Cysteine