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 improvement in GFR was not associated with enhanced glomerular hypertrophy or increased segmental glomerulosclerosis , tubulointerstitial injury , or renal cortical malondialdehyde content .
### Output Text:
The improvement in GFR was not associated with enhanced glomerular hypertrophy or increased segmental glomerulosclerosis , tubulointerstitial injury , or renal cortical <span class="chemical">malondialdehyde</span> content . 