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: PURPOSE : The case of an oncology patient who developed heparin - induced thrombocytopenia with thrombosis ( HITT ) and was treated with argatroban plus catheter - directed thrombolysis ( CDT ) with alteplase is presented .
### Output Text:
PURPOSE : The case of an oncology patient who developed <span class="chemical">heparin</span> - induced thrombocytopenia with thrombosis ( HITT ) and was treated with <span class="chemical">argatroban</span> plus catheter - directed thrombolysis ( CDT ) with alteplase is presented . 