question: Compared to filtered air (NC 91-542/cm3) what was the result of particles (NC 6169-15362/cm3) on OGG1 activity  or mRNA expression levels of repair enzymes  including HO-1, OGG1, and NUDT1?
context: There were no significant associations between exposure and either the OGG1 activity (p = 0.26) or mRNA expression levels of repair enzymes (p > 0.13) including HO-1, OGG1, and NUDT1.