A simplified cyclic adenosine monophosphate–mediated sweat rate test for quantitative measure of cystic fibrosis transmembrane regulator (CFTR) function

2000 ◽  
Vol 137 (6) ◽  
pp. 849-855 ◽  
Author(s):  
Amy Callen ◽  
Marie Diener-West ◽  
Pamela L. Zeitlin ◽  
Ronald C. Rubenstein
Author(s):  
R. Mark Beattie ◽  
Anil Dhawan ◽  
John W.L. Puntis

Gastrointestinal manifestations 156Management of gastrointestinal symptoms in children with CF 158Nutrition in CF 158Nutritional management 159Vitamins 160The incidence of cystic fibrosis (CF) is around 1 in 2500. Cases are diagnosed as a consequence of population screening or high-risk screening, or following presentation with clinical symptoms typical of the disorder. The basic defect is in the CFTR (cystic fibrosis transmembrane conductance regulator) protein which codes for a cyclic adenosine monophosphate-regulated chloride transporter in epithelial cells of exocrine organs. This is involved in salt and water balance across epithelial surfaces. The gene is on chromosome 7. There are multiple known mutations, the most common being ...


1995 ◽  
Vol 269 (1) ◽  
pp. C226-C233 ◽  
Author(s):  
V. Casavola ◽  
R. J. Turner ◽  
C. Guay-Broder ◽  
K. A. Jacobson ◽  
O. Eidelman ◽  
...  

The selective A1-adenosine-receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine (CPX), has been reported to activate Cl- efflux from cystic fibrosis cells, such as pancreatic CFPAC-1 and lung IB3 cells bearing the cystic fibrosis transmembrane regulator(delta F508) mutation, but has little effect on the same process in cells repaired by transfection with wild-type cystic fibrosis transmembrane regulator (O. Eidelman, C. Guay-Broder, P. J. M. van Galen, K. A. Jacobson, C. Fox, R. J. Turner, Z. I. Cabantchik, and H. B. Pollard. Proc. Natl. Acad. Sci. USA 89: 5562-5566, 1992). We report here that CPX downregulates Na+/H+ exchange activity in CFPAC-1 cells but has a much smaller effect on cells repaired with the wild-type gene. CPX also mildly decreases resting intracellular pH. In CFPAC-1 cells, this downregulation is dependent on the presence of adenosine, since pretreatment of the cells with adenosine deaminase blocks the CPX effect. We also show that, by contrast, CPX action on these cells does not lead to alterations in intracellular free Ca2+ concentration. We conclude that CPX affects pH regulation in CFPAC-1 cells, probably by antagonizing the tonic action of endogenous adenosine.


2005 ◽  
Vol 16 (5) ◽  
pp. 2154-2167 ◽  
Author(s):  
Silvia M. Kreda ◽  
Marcus Mall ◽  
April Mengos ◽  
Lori Rochelle ◽  
James Yankaskas ◽  
...  

Previous studies in native tissues have produced conflicting data on the localization and metabolic fate of WT and ΔF508 cystic fibrosis transmembrane regulator (CFTR) in the lung. Combining immunocytochemical and biochemical studies utilizing new high-affinity CFTR mAbs with ion transport assays, we examined both 1) the cell type and region specific expression of CFTR in normal airways and 2) the metabolic fate of ΔF508 CFTR and associated ERM proteins in the cystic fibrosis lung. Studies of lungs from a large number of normal subjects revealed that WT CFTR protein localized to the apical membrane of ciliated cells within the superficial epithelium and gland ducts. In contrast, other cell types in the superficial, gland acinar, and alveolar epithelia expressed little WT CFTR protein. No ΔF508 CFTR mature protein or function could be detected in airway specimens freshly excised from a large number of ΔF508 homozygous subjects, despite an intact ERM complex. In sum, our data demonstrate that WT CFTR is predominantly expressed in ciliated cells, and ΔF508 CFTR pathogenesis in native tissues, like heterologous cells, reflects loss of normal protein processing.


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