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: Mean arterial pressure of conscious rats was 119 + / - 2 mm Hg in control and 194 + / - 5 mm Hg in LNNA rats ( P < 0 . 05 ) .
### Output Text:
Mean arterial pressure of conscious rats was 119 + / - 2 mm Hg in control and 194 + / - 5 mm Hg in <span class="chemical">LNNA</span> rats ( P < 0 . 05 ) . 