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: Urine nitrite levels were significantly increased in the ADR - nephropathy group ( P < 0 . 05 ) .
### Output Text:
Urine <span class="chemical">nitrite</span> levels were significantly increased in the <span class="chemical">ADR</span> - nephropathy group ( P < 0 . 05 ) . 