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: d - 1 given for 4 weeks , elevated blood pressure from 102 + / - 13 to 152 + / - 15 mm Hg and increased the synthesis of ET - 1 and the levels of ET - 1 mRNA in the mesenteric artery ( 240 % and 230 % , respectively ) .
### Output Text:
d - 1 given for 4 weeks , elevated blood pressure from 102 + / - 13 to 152 + / - 15 mm Hg and increased the synthesis of ET - 1 and the levels of ET - 1 mRNA in the mesenteric artery ( 240 % and 230 % , respectively ) . 