1. Volume 2, Issue 3, Pages 397-403 (September 1998)
Loss of CFTR Chloride Channels Alters Salt Absorption by Cystic Fibrosis Airway Epithelia In Vitro 
Joseph Zabner, Jeffrey J Smith, Philip H Karp, Jonathan H Widdicombe, Michael J Welsh 
Molecular Cell 
Volume 2, Issue 3, Pages (September 1998)
DOI: /S (00)

2. Figure 1 Na+ and Cl− Concentrations in ASL
(A–C) Comparison of [Na], [Cl], and volume in non-CF and CF ASL. n = 15 for [Na], n = 16 for [Cl], and n = 31 for volume. Asterisk indicates p <
(D) Expression of CFTR corrected the ASL [Na] in CF epithelia. Treatment of CF epithelia with an adenovirus encoding CFTR increased bumetanide-sensitive Isc (Isc(Bumet)) to 8.3 ± 1.1 μA × cm−2 from 0.1 ± 0.03 in CF epithelia treated with an adenovirus expressing β-galactosidase. n = 6 non-CF, 6 CF, and 6 CF treated with Ad/CFTR. Asterisk indicates p < 0.01 compared to non-CF epithelia and double asterisk indicates p < 0.01 compared to CF epithelia treated with Ad/βGal.
(E) Inhibiting Isc(Amil) increased ASL [Na] in non-CF epithelia. Epithelia were studied in the presence of benzamil in the medium or serum-free medium. Isc(Amil) was 20.3 ± 2.01 μA × cm−2 for control epithelia and 0.5 ± 1.2 μA × cm−2 for epithelia treated with serum-free medium. n = 9 control, 9 benzamil-treated, and 9 serum-free epithelia. Asterisk indicates p < 0.01 compared to control epithelia.
Molecular Cell 1998 2, DOI: ( /S (00) )

3. Figure 2 Effect of Modifying Isc(Amil) on Rate of Liquid Absorption
(A) Amiloride-sensitive and bumetanide-sensitive Isc (indices of transcellular Na+ and Cl− transport, respectively) in non-CF and CF epithelia. Before study, airway epithelia were cultured either in the absence of serum for 4 days, in the presence of serum (Basal), or in the presence of serum plus cAMP agonists (10 μM forskolin and 100 μM IBMX) for 20 hr. cAMP agonists were present during the study. Data are from epithelia shown in (B). For each individual experiment (each point in [B]), 3 epithelia were used to measure electrical properties; bars show mean ± SEM from the epithelia studied.
(B) Relationship between Isc(Amil) and liquid absorption for non-CF (left) and CF (right) epithelia. Prior to study, epithelia were cultured under basal conditions (closed circles), 20 hr of cAMP agonists (open circles), or serum-free medium (diamonds). Each point represents mean ± SEM for Isc(Amil)n = 3 and liquid absorption n = 4–8; some SEM bars are hidden by symbols.
Molecular Cell 1998 2, DOI: ( /S (00) )

4. Figure 3
Effect of Expressing CFTR and Inhibiting Na+ Transport on Liquid Absorption
(A) Expression of CFTR in CF epithelia increases the rate of liquid absorption. CF epithelia were treated with adenovirus expressing β-galactosidase (Ad/βGal) or CFTR (Ad/CFTR) before study. All epithelia were treated with cAMP agonists for 20 hr before study as well as during study. Asterisks indicate p < 0.001; in each group n = 6 for Isc and 21 for absorption. Note that expression of CFTR increased liquid absorption even though Isc(Bumet) increased to values only 1/6 those in non-CF epithelia studied under similar conditions (compare with Figure 2A).
(B) Inhibition of Na+ transport with benzamil inhibits liquid absorption. Epithelia were studied under basal conditions (closed circles) or following 20 hr treatment with cAMP agonists (open circles). Benzamil (1 μM) was included in apical and basolateral solutions as indicated. Each data point is mean from 4–6 epithelia; in some cases SEM bars are hidden by symbols. Basal Isc was 39.7 ± 3.1 μA × cm−2 in non-CF epithelia and 61.3 ± 19.0 μA × cm−2 in CF epithelia; following treatment with benzamil, Isc decreased to 8.6 ± 1.4 μA × cm−2 in non-CF and −0.2 ± 0.4 μA × cm−2 in CF epithelia.
Molecular Cell 1998 2, DOI: ( /S (00) )

5. Figure 4 Cl− Fluxes across Non-CF and CF Epithelia
Open squares indicate basolateral to apical flux and closed squares apical to basolateral flux. Lines are linear least-squares fit. Net absorption (dashed line) is difference between the two unidirectional fluxes. Net absorption was greater in non-CF than CF epithelia, p < n = 12–18. In some cases, SEM bars are hidden by symbols.
Molecular Cell 1998 2, DOI: ( /S (00) )

6. Figure 5 Effect of Rinse Duration on 3H2O Movement
Each data point indicates n = 18 from 3 different experiments. Lines are linear least-squares fit of the data.
Molecular Cell 1998 2, DOI: ( /S (00) )