A NEW DEVICE FOR IN-VIVO MEASUREMENT OF NASAL TRANSEPITHELIAL POTENTIAL DIFFERENCE IN CYSTIC-FIBROSIS PATIENTS AND NORMAL SUBJECTS

Measurement of transepithelial potential difference (PD) on the nasal mucosa bar, been proposed to test for defective ion transport in cysti c fibrosis (CF), and its possible correction after gene therapy or oth er treatments, The ''classical'' method records nasal PD under the inf erior turbinate, with the disadvantage that the tip of the electrode i s not seen by the operator, We have developed a purpose-designed perfu sion electrode for PD recording on the visible, medial/posterior aspec t of the turbinate, We wanted to determine whether such PD recordings adequately discriminate between CP patients and normal subjects,Measur ements of baseline PD and response to a standardized perfusion protoco l were performed in 20 normal subjects and 12 CP patients, Solutions o f amiloride, with or without low chloride buffer were applied for 3 mi n. Increased baseline PD and depolarization after amiloride discrimina ted CF patients from normal subjects. Only one CF patient overlapped w ith the normal range, Superfusion of low chloride buffer with amilorid e and terbutaline caused repolarization in 18 out of 20 normal subject s (90%), consistent with physiological Cl- secretion process, but in n one of the CP patients. We conclude that measurements of potential dif ference on the medial/posterior aspect of the turbinate can discrimina te between cystic fibrosis patients and normal subjects, At this site, visual control of the measurement is possible, and the mucosa is easi ly accessible for subsequent cytological sampling or biopsy.