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: In 5 consecutive patients with rheumatoid arthritis who received intravenous high - dose methylprednisolone ( MP ) therapy ( 1 g daily for 2 or 3 consecutive days ) , a decline in pulse rate was observed , most pronounced on day 4 .
### Output Text:
In 5 consecutive patients with rheumatoid arthritis who received intravenous high - dose <span class="chemical">methylprednisolone</span> ( <span class="chemical">MP</span> ) therapy ( 1 g daily for 2 or 3 consecutive days ) , a decline in pulse rate was observed , most pronounced on day 4 . 