3352
Immunohistochemical analysis of substantia nigra in MP treated mice showed significantly higher number of surviving tyrosine hydroxylase positive cells .
 Chemical: tyrosine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: tyrosine 
Answer:
 Chemical: tyrosine