β-Adrenergic sweat secretion rate determined by evaporimetry is an accurate and reliable technique to assess different levels of CFTR function and to identify patients with CF.

Coke oven workers are exposed to high levels of carcinogenic polyeyclic aromatic hydrocarbons, including benzo [a]

Key points• Using a small glass capillary, an Ussing chamber was designed and used to measure electrical properties across very small pieces (<1 mm 2 ) of freshly dissected epithelia.• The system was applied to small airways of the lung to show that fluids on the airway surfaces are constantly being simultaneously secreted and absorbed. • A new model proposes that the accordion-like structure of folds and pleats in the epithelial lining of the airways serves to secrete fluid within the pleats and to absorb fluid along the folds so that fluid levels on the airway surfaces are maintained automatically and airways do not flood or become too dry.• These results help us understand the first line of lung defence against infections from bacteria and viruses and may be used to treat or prevent lung disease.Abstract Native small airways must remain wet enough to be pliable and support ciliary clearance, but dry enough to remain patent for gas flow. The airway epithelial lining must both absorb and secrete ions to maintain a critical level of fluid on its surface. Despite frequent involvement in lung diseases, the minuscule size has limited studies of peripheral airways. To meet this challenge, we used a capillary to construct an Ussing chamber (area <1 mm 2 ) to measure electrolyte transport across small native airways (∼1 mm ø) from pig lung. Transepithelial potentials (V t ) were recorded in open circuit conditions while applying constant current pulses across the luminal surface of dissected airways to calculate transepithelial electrical conductance (G t ) and equivalent short circuit current (I eq sc ) in the presence and absence of selected Na + and Cl − transport inhibitors (amiloride, GlyH-101, Niflumic acid) and agonists (Forskolin + IBMX, UTP). Considered together the responses suggest an organ composed of both secreting and absorbing epithelia that constitutively and concurrently transport fluids into and out of the airway, i.e. in opposite directions. Since the epithelial lining of small airways is arranged in long, accordion-like rows of pleats and folds that run axially down the lumen, we surmise that cells within the pleats are mainly secretory while the cells of the folds are principally absorptive. This structural arrangement could provide local fluid transport from within the pleats toward the luminal folds that may autonomously regulate the local surface fluid volume for homeostasis while permitting acute responses to maintain clearance.

Genetic diversity among ten varieties of spring wheat used as parents in a diallel cross was assessed through multivariate analysis (D(2)-statistics) and then related to heterosis and SCA effects of their hybrids. The parents fell into three groups. Group I contained the varieties, 'Nobre', 'Girua' and 'Carazinho'; group II contained 'Sonalika', 'Lyallpur' and 'Pitic 62' and group III contained 'Indus 66', 'Balaka', 'Sonora 64rs and 'MSl'. The varieties of group I were good general combiners, while the varieties of group III were poor combiners. Significant heterotic and SCA effects for yield and yield components were observed in the hybrids of the parents belonging to different groups but not in the same group. Genetic divergence between the parents had a positive relationship with heterosis and SCA effects of the hybrids.