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: We investigated the effects of antithrombin , a plasma inhibitor of coagulation factors , in rats with puromycin aminonucleoside - induced nephrosis , which is an experimental model of human nephrotic syndrome .
### Output Text:
We investigated the effects of antithrombin , a plasma inhibitor of coagulation factors , in rats with <span class="chemical">puromycin aminonucleoside</span> - induced nephrosis , which is an experimental model of human nephrotic syndrome . 