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 effects of serial treatment with doxorubicin on dynamic myocardial scintigraphy with [ omega - I - 131 ] heptadecanoic acid ( I - 131 HA ) , and on global left - ventricular function determined echocardiographically , were studied in a group of nine mongrel dogs .
### Output Text:
The effects of serial treatment with <span class="chemical">doxorubicin</span> on dynamic myocardial scintigraphy with <span class="chemical">[ omega - I - 131 ] heptadecanoic acid</span> ( <span class="chemical">I - 131 HA</span> ) , and on global left - ventricular function determined echocardiographically , were studied in a group of nine mongrel dogs . 