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: Atorva reversed dex - induced hypertension ( 129 + / - 0 . 6 mmHg , vs . 135 + / - 0 . 6 mmHg P ' < 0 . 05 ) and decreased plasma superoxide ( 7931 + / - 392 . 8 dex , 1187 + / - 441 . 2 atorva + dex , P < 0 . 0001 ) .
### Output Text:
<span class="chemical">Atorva</span> reversed <span class="chemical">dex</span> - induced hypertension ( 129 + / - 0 . 6 mmHg , vs . 135 + / - 0 . 6 mmHg P ' < 0 . 05 ) and decreased plasma <span class="chemical">superoxide</span> ( 7931 + / - 392 . 8 <span class="chemical">dex</span> , 1187 + / - 441 . 2 <span class="chemical">atorva</span> + <span class="chemical">dex</span> , P < 0 . 0001 ) . 