6325
Importantly , in an ex vivo rat - to - human perfusion model , the survival of rat hearts perfused with human serum treated with rFII ( 83 . 36 +/- 16 . 63 min ) were significantly longer than that of hearts perfused with fresh human serum ( 15 . 94 +/- 4 . 75 min ) .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
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