1756
There were no abnormalities or only isolated degeneration in the 1 - or 2 - wk treatment groups , isolated or scattered degeneration in half of the 3 - wk group , frequent scattered degeneration in the 4 - wk group , scattered or focal degeneration in the 5 - wk group , and extensive degeneration in the 8 - wk group .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 None