CFTR and cystic fibrosis: After 3 hours, neither CO (Figure 6A) nor GE (Figure 6B), had significant effect on TER in either CF or CF+CFTR cell monolayers (i.e., when compared to untreated controls at t=0 (p>0.05) or when the readings were compared between CF and CF+CFTR cell monolayers (p>0.05).