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Articles |
1
Departamento de Toxicologia, Faculdade de Ciêancias Farmacêauticas da Universidade de São Paulo,
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Fundação Jorge Duprat de Figueiredo e Medicina do Trabalho, Fundacentro, and
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Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, 05599-970 São Paulo, SP, Brazil.
a Author for correspondence. Fax 5511-8155579; e-mail ebechara{at}quim.iq.usp.br
5-Aminolevulinic acid (ALA), a heme precursor accumulated in acute intermittent porphyria and lead poisoning, undergoes metal-catalyzed aerobic oxidation at physiological pH to yield reactive free radical species (O2-·>, HO·, and ALA·). We analyzed the relationships between plasma ALA concentrations, blood concentrations of lead, protoporphyrin IX (PP-IX), superoxide dismutase (SOD), and methemoglobin (metHb), and urine chemiluminescence (CL) in samples collected from lead-exposed workers. All variables measured were substantially (P <0.01) higher (28-fold) in the lead-exposed workers (n = 60). Plasma ALA concentrations were, on average, 6-fold higher in lead-exposed workers. We observed positive linear relationships between ALA and lead (r = 0.992), ALA and PP-IX (r = 0.891), ALA and metHb (r = 0.984), lead and SOD (r = 0.948), ALA and urine CL (r = 0.987), and lead and PP-IX (r = 0.993). These data are consistent with our free radical hypothesis for lead poisoning, where ALA distribution to and accumulation in several organs may trigger oxidative stress responses.
Key Words: indexing terms: : toxicology lead superoxide dismutase protoporphyrin IX methemoglobin urine chemiluminescence
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M Ahamed, S Verma, A Kumar, and M K. Siddiqui Delta-aminolevulinic acid dehydratase inhibition and oxidative stress in relation to blood lead among urban adolescents Human and Experimental Toxicology, September 1, 2006; 25(9): 547 - 553. [Abstract] [PDF] |
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A B Engin, D Tuzun, and G Sahin Evaluation of pteridine metabolism in battery workers chronically exposed to lead Human and Experimental Toxicology, July 1, 2006; 25(7): 353 - 359. [Abstract] [PDF] |
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