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: The mean hemorrhagic blood volume was reduced in PCC - treated animals ( 6 . 5 + / - 3 . 1 microL ) compared with saline controls ( 15 . 3 + / - 11 . 2 microL , P = 0 . 015 ) .
### Output Text:
The mean hemorrhagic blood volume was reduced in <span class="chemical">PCC</span> - treated animals ( 6 . 5 + / - 3 . 1 microL ) compared with saline controls ( 15 . 3 + / - 11 . 2 microL , P = 0 . 015 ) . 