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: Dex increased SBP ( 110 + / - 2 - 126 + / - 3 mmHg ; P < 0 . 001 ) and decreased thymus ( P < 0 . 001 ) and bodyweights ( P " < 0 . 01 ) .
### Output Text:
<span class="chemical">Dex</span> increased SBP ( 110 + / - 2 - 126 + / - 3 mmHg ; P < 0 . 001 ) and decreased thymus ( P < 0 . 001 ) and bodyweights ( P " < 0 . 01 ) . 