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 the Ato + Dex group , SBP was increased from 113 + / - 2 to 119 + / - 2 mmHg on Days 4 to 14 , respectively ( P < 0 . 001 ) , but was significantly lower than SBP in the group treated with Dex alone ( P < 0 . 05 ) .
### Output Text:
In the <span class="chemical">Ato</span> + <span class="chemical">Dex</span> group , SBP was increased from 113 + / - 2 to 119 + / - 2 mmHg on Days 4 to 14 , respectively ( P < 0 . 001 ) , but was significantly lower than SBP in the group treated with <span class="chemical">Dex</span> alone ( P < 0 . 05 ) . 