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: Measurements included arterial ketone body ratio ( AKBR , aceto - acetate / 3 - hydroxybutyrate ) and clinical hepatic function parameters .
### Output Text:
Measurements included arterial ketone body ratio ( AKBR , <span class="chemical">aceto - acetate</span> / <span class="chemical">3 - hydroxybutyrate</span> ) and clinical hepatic function parameters . 