Activation of chloride transport in CF airway epithelial cell lines and primary CF nasal epithelial cells by S-nitrosoglutathione

BACKGROUND: It has been suggested that low μM concentrations of S-nitrosoglutathione (GSNO), an endogenous bronchodilator, may promote maturation of the defective cystic fibrosis (CF) transmembrane conductance regulator (CFTR). Because nitric oxide (NO) and GSNO levels appear to be low in the CF airway, there is an interest in the possibility that GSNO replacement could be of therapeutic benefit in CF. METHODS: The effect of GSNO on chloride (Cl(-)) transport was investigated in primary nasal epithelial cells obtained from CF patients homozygous for the delF508 mutation, as well as in two CF cell lines (CFBE and CFSME), using both a fluorescent Cl(- )indicator and X-ray microanalysis. Maturation of delF508 CFTR was determined by immunoblotting. RESULTS: Treatment with 60 μM GSNO for 4 hours increased cAMP-induced chloride efflux in nasal epithelial cells from 18 out of 21 CF patients, but did not significantly affect Cl(- )efflux in cells from healthy controls. This Cl(- )efflux was confirmed by measurements with a fluorescent Cl(- )indicator in the CFBE and CFSME cell lines. The effect of GSNO on Cl(- )efflux in CFBE cells could be inhibited both by a specific thiazolidinone CFTR inhibitor (CFTR(inh)-172) and by 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid (H(2)DIDS). X-ray microanalysis showed that, following 4 hours incubation with 60 μM GSNO, cAMP agonists caused a decrease in the cellular Cl(- )concentration in CFBE cells, corresponding to Cl(- )efflux. GSNO exposure resulted in an increase in the protein expression and maturation, as shown by immunoblot analysis. GSNO did not increase the cytosolic Ca(2+ )concentration in cultured airway epithelial cells. CONCLUSION: Previous studies have suggested that treatment with GSNO promotes maturation of delF508-CFTR, consistent with our results in this study. Here we show that GSNO increases chloride efflux, both in the two CF cell lines and in primary nasal epithelial cells from delF508-CF patients. This effect is at least in part mediated by CFTR. GSNO may be a candidate for pharmacological treatment of the defective chloride transport in CF epithelial cells

ATP release via anion channels

ATP serves not only as an energy source for all cell types but as an ‘extracellular messenger-for autocrine and paracrine signalling. It is released from the cell via several different purinergic signal efflux pathways. ATP and its Mg2+ and/or H+ salts exist in anionic forms at physiological pH and may exit cells via some anion channel if the pore physically permits this. In this review we survey experimental data providing evidence for and against the release of ATP through anion channels. CFTR has long been considered a probable pathway for ATP release in airway epithelium and other types of cells expressing this protein, although non-CFTR ATP currents have also been observed. Volume-sensitive outwardly rectifying (VSOR) chloride channels are found in virtually all cell types and can physically accommodate or even permeate ATP4- in certain experimental conditions. However, pharmacological studies are controversial and argue against the actual involvement of the VSOR channel in significant release of ATP. A large-conductance anion channel whose open probability exhibits a bell-shaped voltage dependence is also ubiquitously expressed and represents a putative pathway for ATP release. This channel, called a maxi-anion channel, has a wide nanoscopic pore suitable for nucleotide transport and possesses an ATP-binding site in the middle of the pore lumen to facilitate the passage of the nucleotide. The maxi-anion channel conducts ATP and displays a pharmacological profile similar to that of ATP release in response to osmotic, ischemic, hypoxic and salt stresses. The relation of some other channels and transporters to the regulated release of ATP is also discussed

Web applicatin development usin the PEAR library

Niniejszy artykuł prezentuje możliwości biblioteki PEAR w procesie szybkiego wytwarzania aplikacji internetowych w języku PHP. Na podstawie przykładów zostaną zaprezentowane zalety oraz korzyści płynące z użytkowania biblioteki PEAR. Stosowanie repozytoriów klas z niniejszej biblioteki pozwala znacznie uprościć i zoptymalizować kod w procesie programowania aplikacji PHP.The paper presents the possibility of the PEAR library in the rapid production of the PHP applications. The advantages and benefits of the use of the PEAR are going to be presented. Use of this repository class library can significantly simplify and optimize the PHP code and accelerate the process of the web application programming

Numeryczne modelowanie trójwymiarowych struktur plecionych z drewna

Numerical modeling of textile inspired three-dimensional woven timber structures. The paper presents the numerical analysis of textile inspired three-dimensional woven timber structures. The numerical model built in ABAQUS 6.11 software simulated the possible behaviour of the structures under loading.Numeryczne modelowanie trójwymiarowych struktur plecionych z drewna. W artykule przedstawiono sposób modelowania trójwymiarowych struktur plecionych z drewna. Na podstawie analiz przeprowadzonych na płaskich strukturach wybrano materiał, rodzaj elementu skończonego i rodzaj splecenia. Opracowano model numeryczny w programie ABAQUS 6.11 struktury trójwymiarowej o kształcie półwalca i pokazano symulację pracy modelu pod działaniem odpowiednich obciążeń i podczas zadawania interakcji w poszczególnych obszarach

The 20-pS chloride channel of the human airway epithelium.

The single-channel inside-out patch clamp technique was used to characterize chloride channels in the apical membranes of human airway epithelial cells maintained in primary culture. Patches were obtained from single isolated cells or from cells at the edges of confluent groups. The channel seen most often, in 24% of all patches, had a conductance of approximately 20 pS and had a linear current-voltage relationship in symmetric chloride solutions. The anion selectivity sequence for the channel was NO3- greater than Cl- greater than HCO3-, and it was impermeable to gluconate ions, indicating that the channel diameter lies between 4.7 and 5.5 A. Current through the channel saturated at high chloride concentrations, and the relationship between channel current and chloride concentration could be approximated by the Michaelis-Menten equation. Analysis of the channel's anion permeability and its current vs. concentration relationship indicates that it can be described by the one-ion channel theory, with a relatively weak binding site inside the channel. Histograms of channel open and closed durations were constructed using the log binning technique and could be well fitted by triple exponential distributions, suggesting that the channel has at least three open and three closed states