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: Conversion to sirolimus ameliorates cyclosporine - induced nephropathy in the rat : focus on serum , urine , gene , and protein renal expression biomarkers .
### Output Text:
Conversion to <span class="chemical">sirolimus</span> ameliorates <span class="chemical">cyclosporine</span> - induced nephropathy in the rat : focus on serum , urine , gene , and protein renal expression biomarkers . 