Blockade of plasmid replication mediated by peptide nucleic acids.

Because peptide nucleic acids (PNAs) are capable of blocking amplification of deoxyribonucleic acid (DNA) by Taq DNA polymerase in vitro, we postulated that PNAs might be able to block replication in vivo. To explore this possibility, we assessed the ability of PNA to specifically block the replication of pUC19 plasmids by allowing a PNA, directed against segments of the Ampr sequence to bind to pUC19 prior to electroporation into Escherichia coli, strain DH10B. Colonies produced by this maneuver not only remained sensitive to ampicillin but were also incapable of blue color production on X-gal-containing media, thus demonstrating true blockade of pUC19 replication, rather than antisense activity.

Etanercept ameliorates sarcoidosis arthritis and skin disease.

Sarcoidosis is a systemic disorder of unknown etiology characterized by its pathological hallmark, the noncaseating granuloma. In granulomatous diseases, the proinflammatory peptide mediators, including tumor necrosis factor-alpha (TNF-alpha), are increased in the blood and fluids surrounding the activated macrophages. We describe a patient with chronic sarcoidosis arthropathy and lupus pernio resistant to corticosteroids and disease modifying antirheumatic agents, who responded to the addition of etanercept.