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 bladder afferent cells in DRG , p75 ( NTR ) - IR was also increased ( P < or = 0 . 01 ) with cystitis .
### Output Text:
In bladder afferent cells in DRG , p75 ( NTR ) - IR was also increased ( P < or = 0 . 01 ) with cystitis . 