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: At study end , statistically significant percentage reductions from baseline within groups and between groups were observed in SBP ( T + A [ - 27 . 4 % ] ; A [ - 16 . 6 % ] ) and DBP ( T + A [ - 20 . 1 % ] ; A [ - 13 . 3 % ] ) ( all , P < 0 . 05 ) .
### Output Text:
At study end , statistically significant percentage reductions from baseline within groups and between groups were observed in SBP ( T + A [ - 27 . 4 % ] ; A [ - 16 . 6 % ] ) and DBP ( T + A [ - 20 . 1 % ] ; A [ - 13 . 3 % ] ) ( all , P < 0 . 05 ) . 