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: MA may selectively damage the medial temporal lobe and , consistent with metabolic studies , the cingulate - limbic cortex , inducing neuroadaptation , neuropil reduction , or cell death .
### Output Text:
<span class="chemical">MA</span> may selectively damage the medial temporal lobe and , consistent with metabolic studies , the cingulate - limbic cortex , inducing neuroadaptation , neuropil reduction , or cell death . 