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: The effect of recombinant human insulin - like growth factor - I on chronic puromycin aminonucleoside nephropathy in rats .
### Output Text:
The effect of recombinant human insulin - like growth factor - I on chronic <span class="chemical">puromycin aminonucleoside</span> nephropathy in rats . 