[Perforations following endoscopic retrograde cholangiopancreatography (ERCP)]. / Perforaciones post colangiopancreatografía endoscópica retrógrada (CPRE). Manejo quirúrgico.

Endoscopic retrograde cholangiopancreatography (ERCP) associated with sphincterotomy is a useful procedure that is widely used in cases of choledocholithiasis and bile duct obstruction. In spite of being a safe test, there is a risk of complications like pancreatitis, haemorrhaging or perforation. Post-ERCP duodenal perforation is a rare event but has serious consequences if it is not treated early. The lesion mechanism, the place and extension of the perforation, as well as the clinical picture and radiographic findings will guide patient management, which must be individualised and constantly reevaluated. Its mortality is closely related to diagnostic and therapeutic delay. In those cases where a conservative attitude is adopted, close vigilance will be maintained facing the possibility of a worsening of the clinical picture and a change in its management.

Fast and stable recording of birefringence and holographic gratings in an azo-polymethacrylate using a single nanosecond light pulse.

Pulsed light-induced recording in azobenzene polymers has recently been studied due to its potential use in optical storage applications. In this paper we study the photoinduced birefringence (Deltan) and holographic grating recording in an azobenzene side chain liquid-crystalline polymethacrylate irradiating with a single 4 ns light pulse at 532 nm. For some irradiation conditions, Deltan grows in less than 50 ns reaching an essentially stable value of about 10(-2). Holographic gratings have been registered using intensity and polarization patterns. Fast response and stability, similar to those of Deltan, was observed in the holographic recording process. Both light-induced anisotropy and relief contributions have been found in the case of gratings recorded using intensity patterns, relief being the dominant contribution at high recording energies. Polarization gratings have been recorded using two orthogonally circularly polarized beams. The resultant gratings showed stable efficiencies up to 0.8% (measured at 633 nm in 1-mum-thick films) and no measurable relief was observed.

Tetrathiafulvalene derivatives as NLO-phores: synthesis, electrochemistry, Raman spectroscopy, theoretical calculations, and NLO properties of novel TTF-derived donor-pi-acceptor dyads.

Novel pi-conjugated donor-acceptor chromophores, based on the strong electron-donating tetrathiafulvalene moiety and different electron-withdrawing acceptors, exhibit large second-order optical nonlinearities. The effect of increasing the length of the polyenic spacer and the influence of the nature of the acceptor moiety on the NLO properties have been studied by using the electric field-induced second-harmonic generation (EFISH) technique as well as by semiempirical and ab initio theoretical calculations. A charge-transfer band has been observed in the absorption spectra of these D-pi-A compounds that undergoes an hypsochromic shift when increasing the number of vinylenic spacer units connecting both donor and acceptor moieties. The degree of the intramolecular charge transfer from the donor to the acceptor has also been analyzed by means of Raman spectroscopy.