Use of Impella Recover 2.5 left ventricular assist device in patients with cardiogenic shock or undergoing high-risk percutaneous coronary intervention procedures: experience of a high-volume center.

AIM: Percutaneous coronary interventions are increasingly applied to high-risk patients. The availability of hemodynamic support devices offers a promising option to prevent and treat low-output syndrome in these patients. The aim of this study was to evaluate the feasibility, safety and efficacy of the Impella Recover'' LP 2.5 left ventricular assist device in patients with cardiogenic shock or undergoing high-risk percutaneous coronary interventions. METHODS: Eleven patients presenting cardiogenic shock (N=6) or scheduled for high-risk percutaneous revascularization (N=5) were evaluated. The Impella pump was successfully implanted in all patients, except one. When implanted, the device was correctly positioned in the left ventricle and remained in a stable position. RESULTS: Bleedings occurred in 7 patients (5 of them presented cardiogenic shock), while renal failure and severe thrombocytopenia were observed in 4 and 1 patients respectively, all with cardiogenic shock. During high-risk procedures, the Impella pump succeeded in obtaining hemodynamic stability, while in only two patients with cardiogenic shock the device determined a significant improvement of hemodynamic variables. All elective patients and two patients with cardiogenic shock were discharged from the hospital and were still alive at 30-day follow-up. CONCLUSION: These data, although preliminary due to the limited sample size, demonstrated the feasibility, safety and efficacy of the Impella Recover LP 2.5 during high-risk percutaneous procedures, even though the benefits of prophylactic deployment of such a system have to be further investigated. The use of Impella Recover LP 2.5 in patients with cardiogenic shock is feasible and safe, however it maybe insufficient in reversing an advanced cardiogenic shock which, probably, has to be treated with more powerful left ventricular assist devices.

Venture wire control catheter in percutaneous treatment of complex coronary bifurcation. A case report.

We present a case report of a man with atherosclerotic involvement of a left main trifurcation treated by the Venture wire control catheter. The patient was submitted to primary percutaneous transluminal coronary angioplasty (PTCA) in a primary center for acute occlusion of the left anterior descending artery, then he was transferred to our tertiary center to perform left main trifurcation revascularization that was unsuccessful by traditional approach. In our high volume center (operator >600 PTCA/year) as well, the attempts at crossing the lesion with a number of different guidewires failed because of the extreme angulation of the circumflex artery. At last, a successful attempt was reached using the Venture wire control, a low profile catheter with a tip that can be deflected up to 90 degrees . Once the lesion was crossed and wiring of other branches obtained, crush stenting of the left anterior descending artery and intermediate ramus and T-stent of the circumflex artery were performed with an optimal angiographic result.

QTL analysis of proteome and transcriptome variations for dissecting the genetic architecture of complex traits in maize.

In this review, we present some studies on genetic analysis of proteome and transcriptome variations, which exemplify new strategies for a better understanding of the molecular and genetic bases of complex traits. A large genetic variability was revealed at the proteome expression level, which raised the possibility to predict phenotypical performance on the basis of gene product variability. This approach yielded limited results, but could be re-newed by extensive identification of proteins now allowed by mass spectrometry. The dissection of the genetic basis of the variation of individual protein amounts proves very powerful to select 'candidate' proteins, physiologically relevant for a given phenotypical trait, as shown by a study on the effect of water stress in maize. In order to investigate factors of grain quality in maize, we selected a regulatory locus known to control the expression of several storage protein genes, Opaque-2, and investigated the relationships between variability in zein amount and composition and the molecular polymorphism at this locus. Moreover, a QTL analysis revealed that the variability in Opaque-2 transcript abundance was controlled by several polymorphic trans-acting regulators unlinked to the Opaque-2 structural gene. Such genetic approaches should represent additional tools for physiological analysis of the huge amounts of data generated by transcritome and proteome projects.

Quantification of individual zein isoforms resolved by two-dimensional electrophoresis: genetic variability in 45 maize inbred lines.

A two-dimensional (2-D) electrophoresis procedure was optimized to obtain well-resolved and reproducible patterns of zein polypeptides in maize. All zein isoforms obtained through zein-specific extraction were observed from whole meal extracted with a urea/Triton/2-mercaptoethanol solution. Loading the protein samples at the acidic side of the gradient, using an amino acid solution as catholyte and running for a short time period under high Vh reduced shrinking and instability at the basic side of the isoelectric focusing (IEF) gels. Good quality and reproducible 2-D patterns were thus obtained, allowing automatic spot quantification. A linear relationship between spot intensity and zein isoform amount was established for 20 of 22 zeins detected in a 5.5-8.5 pH range using colloidal Coomassie blue staining in one maize line. The analysis of 45 genetically diverse inbred lines allowed the detection of 59 isoforms belonging to the four classes of zeins, and revealed a large qualitative and quantitative variability of individual isoforms. The classical decrease in zein amount in o2 mutant genotype was observed, and could be quantified for every isoform. The improved technique will be useful to dissect the genetic control of zein expression in maize.

Breakdown of a conservation law in incommensurate systems.

We show that invariance properties of the Lagrangian of an incommensurate system, as described by the Frenkel-Kontorova model, imply the existence of a generalized angular momentum that is an integral of motion if the system remains floating. The behavior of this quantity can therefore monitor the character of the system as floating (when it is conserved) or locked (when it is not). We find that, during the dynamics, the nonlinear couplings of our model cause parametric phonon excitations that lead to the appearance of Umklapp terms and to a sudden deviation of the generalized momentum from a constant value, signaling a dynamical transition from a floating to a pinned state. We point out that this transition is related but does not coincide with the onset of sliding friction, which can take place when the system is still floating.

Onset of sliding friction in incommensurate systems

We study the dynamics of an incommensurate chain sliding on a periodic lattice, modeled by the Frenkel-Kontorova Hamiltonian with initial kinetic energy, without damping and driving terms. We show that the onset of friction is due to a novel type of dissipative parametric resonances, involving several resonant phonons which are driven by the (dissipationless) coupling of the center of mass motion to the phonons with the wave vector related to the modulating potential. We establish quantitative estimates for their existence in finite systems and point out the analogy with the induction phenomenon in Fermi-Ulam-Pasta lattices.