Abstract: The invention is directed to a piston skirt oil seal system comprising a piston with a skirt operating in a cylinder chamber between an oil sump and a combustion chamber in an internal combustion engine. A first retainer attaches to the piston skirt, and a second retainer attaches to a cylinder wall defining the cylinder chamber above the oil sump. A boot made of a flexible, impervious membrane extends between the first and second retainers. The boot serves as a barrier preventing the migration of oil from the oil sump into the combustion chamber reducing the amount of unburned hydrocarbons introduced to the catalyst. To overcome gas leakage and friction, at least one self-lubricating or gas lubricated ring attaches to the piston above the boot. In an alternative embodiment, the boot forms an oil migration barrier through the use of a series of concentric rings linked together in a telescoping arrangement.

Abstract: Cystic fibrosis (CF), a lethal genetic disease associated with a defect in Cl transport, is caused by mutations in the gene coding for cystic fibrosis transmembrane conductance regulator (CFTR). Surprisingly, not only wild type CFTR, but several naturally-occurring CFTR mutants carrying a defect in the first nucleotide binding fold (NFB1) all expressed cAMP-activatable Cl currents. Treatment of the CFTR mutants with appropriate concentrations of methylxanthine phosphodiesterase inhibitor (which increases cAMP levels) activated Cl conductance to near wild type levels. The present invention thus provides a new avenue for treating cystic fibrosis by the administration of therapeutically effective amounts of compounds which elevate cAMP levels. Dosage and patient responsiveness to treatment, as well as relative efficacies of the compounds being or to be administered can also be determined in accordance with the methods of present invention.