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: Furthermore , increased phosphorylation of MAPK family members , especially the P - P38 / P38 ratio was found in cardiac tissues .
### Output Text:
Furthermore , increased phosphorylation of MAPK family members , especially the P - P38 / P38 ratio was found in cardiac tissues . 