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: High - dose tranexamic Acid is associated with nonischemic clinical seizures in cardiac surgical patients .
### Output Text:
High - dose <span class="chemical">tranexamic Acid</span> is associated with nonischemic clinical seizures in cardiac surgical patients . 