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: Dexamethasone induced the transcriptional factor CHOP , a marker for chronic ER stress , in the anterior segment tissues , and Chop deletion reduced ER stress in these tissues and prevented dexamethasone - induced ocular hypertension .
### Output Text:
<span class="chemical">Dexamethasone</span> induced the transcriptional factor CHOP , a marker for chronic ER stress , in the anterior segment tissues , and Chop deletion reduced ER stress in these tissues and prevented <span class="chemical">dexamethasone</span> - induced ocular hypertension . 