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: The participants had physical examination , medical record extraction , and venipuncture , CD4 + T - cell counts determination , measurement of depression symptoms ( using the self - report Center for Epidemiological Studies - Depression Scale ) , and alcohol use assessment at enrollment , and semiannually until March 2000 .
### Output Text:
The participants had physical examination , medical record extraction , and venipuncture , CD4 + T - cell counts determination , measurement of depression symptoms ( using the self - report Center for Epidemiological Studies - Depression Scale ) , and <span class="chemical">alcohol</span> use assessment at enrollment , and semiannually until March 2000 . 