In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: In addition to increases in p75 ( NTR ) - IR in DRG cell bodies , increases ( P < or = 0 . 001 ) in pericellular ( encircling DRG cells ) p75 ( NTR ) - IR in DRG also increased .
### Output Text:
In addition to increases in p75 ( NTR ) - IR in DRG cell bodies , increases ( P < or = 0 . 001 ) in pericellular ( encircling DRG cells ) p75 ( NTR ) - IR in DRG also increased . 