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 steroids also caused a dose - dependent delay in NMDA ( 257 mg / kg , s . c . ) - induced lethality , but did not completely protect against NMDA seizures or lethality .
### Output Text:
The <span class="chemical">steroids</span> also caused a dose - dependent delay in <span class="chemical">NMDA</span> ( 257 mg / kg , s . c . ) - induced lethality , but did not completely protect against <span class="chemical">NMDA</span> seizures or lethality . 