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: She was treated with heparin , dipyridamole and hemodialysis ; and after more than three months , her urinary output rose above 500 ml ; and six months after the onset of anuria , dialysis treatment was stopped .
### Output Text:
She was treated with <span class="chemical">heparin</span> , <span class="chemical">dipyridamole</span> and hemodialysis ; and after more than three months , her urinary output rose above 500 ml ; and six months after the onset of anuria , dialysis treatment was stopped . 