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In the livers , oxidative / nitrosative stress was evidenced by increased 3 - nitrotyrosine ( 3 - NT ) and thiobarbituric acid reactive substances ( TBARS ) formation and a significant decrease in Cu / Zn superoxide dismutase ( SOD ) activity .
 3 - nitrotyrosine, 3 - NT, thiobarbituric acid, Cu, Zn, superoxide
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 3 - nitrotyrosine, 3 - NT, thiobarbituric acid, Cu, Zn, superoxide