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 most important findings were that compared with values in control subjects , end - systolic left ventricular posterior wall dimension and percent of left ventricular posterior wall thickening in doxorubicin - treated patients were decreased at baseline study and these findings were more clearly delineated with dobutamine stimulation .
### Output Text:
The most important findings were that compared with values in control subjects , end - systolic left ventricular posterior wall dimension and percent of left ventricular posterior wall thickening in <span class="chemical">doxorubicin</span> - treated patients were decreased at baseline study and these findings were more clearly delineated with <span class="chemical">dobutamine</span> stimulation . 