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: These studies were undertaken to determine if neonatal administration of MSG produced permanent alterations in seizure susceptibility , since previous investigations were inconclusive .
### Output Text:
These studies were undertaken to determine if neonatal administration of <span class="chemical">MSG</span> produced permanent alterations in seizure susceptibility , since previous investigations were inconclusive . 