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: MEASUREMENTS : Plasma total , low - density lipoprotein ( LDL ) , and high - density lipoprotein ( HDL ) cholesterol , and triglycerides ; and laboratory and clinical evidence of adverse events monitored periodically throughout the study .
### Output Text:
MEASUREMENTS : Plasma total , low - density lipoprotein ( LDL ) , and high - density lipoprotein ( HDL ) <span class="chemical">cholesterol</span> , and <span class="chemical">triglycerides</span> ; and laboratory and clinical evidence of adverse events monitored periodically throughout the study . 