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: With 100 micrograms denopamine , almost complete restoration of cardiac performance was attained , associated with a slight increase in heart rate .
### Output Text:
With 100 micrograms <span class="chemical">denopamine</span> , almost complete restoration of cardiac performance was attained , associated with a slight increase in heart rate . 