15878
However , Pb ( 2 + ) - induced cardiotoxicity has never been investigated yet and the exact mechanism of Pb ( 2 + ) associated cardiotoxicity has not been studied .
 Pb ( 2 + ), Pb ( 2 + )
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Pb ( 2 + ), Pb ( 2 + )