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 addition PJ34 significantly reduced the DOX - induced increase in the serum lactate dehydrogenase and creatine kinase activities but not metalloproteinase activation in the heart .
### Output Text:
In addition <span class="chemical">PJ34</span> significantly reduced the <span class="chemical">DOX</span> - induced increase in the serum <span class="chemical">lactate</span> dehydrogenase and <span class="chemical">creatine</span> kinase activities but not metalloproteinase activation in the heart . 