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: At 5 months glomerular sclerosis was found in 7 . 6 + / - 3 . 4 % of the glomeruli of PAN rats ; glomeruli of the controls were normal .
### Output Text:
At 5 months glomerular sclerosis was found in 7 . 6 + / - 3 . 4 % of the glomeruli of <span class="chemical">PAN</span> rats ; glomeruli of the controls were normal . 