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: Some of these findings represented the most extreme abnormalities seen in the entire group of patients ; some increased further during therapy .
### Output Text:
Some of these findings represented the most extreme abnormalities seen in the entire group of patients ; some increased further during therapy . 