22878
Using wildtype ( WT ) and Nf1 ( - / - ) chondrocyte cultures in vitro , we show that FGF2 pulse - stimulation triggers rapid ERK1 / 2 phosphorylation in both genotypes , but that return to the basal level is delayed in Nf1 ( - / - ) chondrocytes .
 None
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