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: We report a case of Wilson ' s disease with chronic liver disease ; moreover , in our patient , presenting also with high levels of state anxiety without depression , 99mTc - ECD - SPECT showed cortical hypoperfusion in frontal lobes , more marked on the left frontal lobe .
### Output Text:
We report a case of Wilson ' s disease with chronic liver disease ; moreover , in our patient , presenting also with high levels of state anxiety without depression , 99mTc - ECD - SPECT showed cortical hypoperfusion in frontal lobes , more marked on the left frontal lobe . 