Reliability, validity and feasibility of nail ultrasonography in psoriatic arthritis.

Objective: To determine the feasibility, reliability and validity of nails ultrasonography in psoriatic arthritis as an outcome measure.

Methods: Pilot prospective single-centre study of eight ultrasonography parameters in B mode and power Doppler concerning the distal interphalangeal (DIP) joint, the matrix, the bed and nail plate. Intra-observer and inter-observer reliability was evaluated for the seven quantitative parameters (ICC and kappa).

Cytochrome P450 interactions and clinical implication in rheumatology.

There are many potential drug interactions that involve the complex cytochromes P450 (CYP) enzyme system when treatments for chronic inflammatory rheumatic diseases are used. This iatrogenic risk is increased in patients taking multiple drugs such as those with rheumatoid arthritis or gout, whatever the type of CYP interaction (substrate, inducer, or inhibitor of one of the CYP isoenzymes). Some of these CYP interactions may have clinical consequences, sometimes serious (overdose or therapeutic failure) and are often unrecognized by clinicians.