Imaging for trans-catheter pulmonary stent-valve implantation without angiography: role of intravascular ultrasound.

Patients with stenosed biologic pulmonary conduits require redo cardiac surgery to prevent severe right ventricular dysfunction. Following the latest trends, the trans-catheter pulmonary stent-valve implantation represents a new fascinating alternative carrying a lower operative risk, compared with the standard open-heart re-intervention. Traditionally, the pulmonary stent valve is positioned off pump, under fluoroscopic control, and requires angiographies. However, alternative tools not requiring contrast injections for the intra-operative cardiac imaging have to be also considered strongly. The usefulness of intravascular ultrasound for the positioning of aortic endoprosthesis has already been proven in previous reports and, following the same principle, we have started to routinely implant balloon-expandable stent valves (Edwards Sapien? THV) in stenosed pulmonary valve conduits using intravascular ultrasound for the stent-valve positioning without angiography. We describe the intra-operative intravascular imaging technique with technical details.

First-principles periodic calculation of four-body spin terms in high-Tc cuprate superconductors

A general mapping between the energy of pertinent magnetic solutions and the diagonal terms of the spin Hamiltonian in a local representation provides the first general framework to extract accurate values for the many body terms of extended spin Hamiltonians from periodic first-principle calculations. Estimates of these terms for La2CuO4, the paradigm of high-Tc superconductor parent compounds, and for the SrCu2O3 ladder compound are reported. For La2CuO4, present results support experimental evidence by Toader et al. [Phys. Rev. Lett. 94, 197202 (2005)]. For SrCu2O3 even larger four-body spin amplitudes are found together with Jl/Jr=1 and non-negligible ferromagnetic interladder exchange.

First-principles periodic calculation of four-body spin terms in high-Tc Cuprate superconductors

A general mapping between the energy of pertinent magnetic solutions and the diagonal terms of the spin Hamiltonian in a local representation provides the first general framework to extract accurate values for the many body terms of extended spin Hamiltonians from periodic first-principle calculations. Estimates of these terms for La2CuO4, the paradigm of high-Tc superconductor parent compounds, and for the SrCu2O3 ladder compound are reported. For La2CuO4, present results support experimental evidence by Toader et al. [Phys. Rev. Lett. 94, 197202 (2005)]. For SrCu2O3 even larger four-body spin amplitudes are found together with Jl/Jr=1 and non-negligible ferromagnetic interladder exchange.

Therapeutic monitoring of antidepressants in the era of pharmacogenetics studies.

As for other drugs, there is a large interindividual variability of the plasma concentrations of antidepressants for a given dose. Within the last 2 decades, a very large number of pharmacogenetic studies have made it possible to understand the importance of genetic factors on the disposition of drugs in the organism, many of them at the levels of drug metabolism. Polymorphism of CYP2D6 and of other drug-metabolizing enzymes may thus lead to very large differences in drug exposure between patients and possibly also to toxicity or ineffective drug concentrations in some subjects. In consequence, dose recommendations of antidepressants based on genotypes, justified by the principle of administering bioequivalent individualized drug doses, are now proposed. However, blood (and thus possibly brain) concentrations also depend on other factors than the genetic makeup of the patients. Therapeutic drug monitoring of antidepressants allows us to take into account the influence of factors such as comedications, diet, smoking habit, impaired organ function, and compliance. Therapeutic drug monitoring and genotyping are thus complementary, and their combined use contributes to improve pharmacotherapy with antidepressants and other drugs.

The Poor Representation of the Poor in a Comparative Perspective

Due to diverging levels of political influence of various income groups, political institutions likely reflect¦the policy preferences of certain groups of citizens better than others, independently of their numerical¦weight. This runs counter the egalitarian principle of 'one citizen, one vote'. The present article documents¦a general trend of underrepresentation of the preferences of relatively poor citizens both by¦parties and by governments across Western democracies, although important cross-national differences¦exist.