4387
Eight hr of acidosis caused a significant ( P less than 0 . 01 ) decrease in P50 in vitro which fell from 29 . 0 to 24 . 4 torr .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None