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: Loss of endothelial cell - derived nitric oxide ( NO ) in hypertension is a hallmark of arterial dysfunction .
### Output Text:
Loss of endothelial cell - derived <span class="chemical">nitric oxide</span> ( <span class="chemical">NO</span> ) in hypertension is a hallmark of arterial dysfunction . 