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: Comparison of the mean ALT values revealed significantly higher mean alanine aminotransferase ( ALT ) values in the control group than the prophylactic lamivudine group ; 154 : 64 ( p < 0 . 32 ) .
### Output Text:
Comparison of the mean ALT values revealed significantly higher mean <span class="chemical">alanine</span> aminotransferase ( ALT ) values in the control group than the prophylactic <span class="chemical">lamivudine</span> group ; 154 : 64 ( p < 0 . 32 ) . 