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: Histological examination showed that losartan could prevent tubular atrophy , interstitial infiltration and fibrosis in ADR nephropathy .
### Output Text:
Histological examination showed that <span class="chemical">losartan</span> could prevent tubular atrophy , interstitial infiltration and fibrosis in <span class="chemical">ADR</span> nephropathy . 