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: These findings suggest that 5 - FU can negatively affect both cell proliferation and hippocampal dependent working memory and that these deficits can be reversed by the simultaneous administration of the antidepressant Fluoxetine .
### Output Text:
These findings suggest that <span class="chemical">5 - FU</span> can negatively affect both cell proliferation and hippocampal dependent working memory and that these deficits can be reversed by the simultaneous administration of the antidepressant <span class="chemical">Fluoxetine</span> . 