2253
In vivo , prolidase overexpression extended the survival of 4 out of 6 mice by 4 - 8h against exposure to two 1 x LD50 doses of DFP .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None