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: Because of the National Acute Spinal Cord Injury Studies ( NASCIS ) , high - dose methylprednisolone became the standard of care for the acute spinal cord injury .
### Output Text:
Because of the National Acute Spinal Cord Injury Studies ( NASCIS ) , high - dose <span class="chemical">methylprednisolone</span> became the standard of care for the acute spinal cord injury . 