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: Alkaline phosphatase and glucose were markedly and transiently elevated in proximal tubular damage and N - acetyl - beta - glucosaminidase showed a sustained elevation in papillary damage .
### Output Text:
Alkaline phosphatase and <span class="chemical">glucose</span> were markedly and transiently elevated in proximal tubular damage and N - acetyl - beta - glucosaminidase showed a sustained elevation in papillary damage . 