Impact of perioperative blood transfusions on oncologic outcomes after radical cystectomy: A systematic review and meta-analysis of comparative studies

This study aimed at systematically analyzing and evaluating the impact of perioperative blood transfusions (PBT) on oncologic outcomes of patients undergoing radical cystectomy for bladder cancer. This systematic review follows the recommendations of the Cochrane Handbook for Systematic Reviews and Interventions and was conducted in line with the PRISMA statement and the AMSTAR II criteria. A comprehensive database search was performed based on the PICO criteria. Two independent reviewers performed all screening steps and quality assessment. Risk of bias and certainty in evidence were assessed with the Newcastle Ottawa Scale for non-randomized trials and the GRADE approach. Of 1123 identified studies 20 were eligible for qualitative analysis and 15 for quantitative analysis reporting on 21,915 patients. Receiving a PBT was associated with an increased risk of all-cause mortality (hazard ratio (HR) [95% confidence interval (CI)]: 1.29 [1.18, 1.40]; p < 0.001), cancer-specific mortality (HR [CI]: 1.27 [1.15; 1.41]; p < 0.001) and disease recurrence (HR [CI]: 1.22 [1.12; 1.34]; p < 0.001). Subgroup analysis of transfusion timing revealed a significantly increased risk of mortality with intraoperative or combined intra- and postoperative transfusions compared to postoperative transfusion only for all three outcomes (p < 0.001). Leukocyte-depletion was associated with increased all-cause mortality, but not cancer-specific mortality. The administration of PBT negatively impacts oncological outcomes after radical cystectomy. Therefore, careful treatment indication and strict adherence to transfusion guidelines is encouraged in order to avoid adverse effects during the perioperative course.

Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high-T c superconductor

Charge density modulations have been observed in all families of high-critical temperature (T _c) superconducting cuprates. Although they are consistently found in the underdoped region of the phase diagram and at relatively low temperatures, it is still unclear to what extent they influence the unusual properties of these systems. Using resonant x-ray scattering, we carefully determined the temperature dependence of charge density modulations in YBa₂Cu₃O_7-δ and Nd_{1+ x} Ba_{2- x} Cu₃O_7-δ for several doping levels. We isolated short-range dynamical charge density fluctuations in addition to the previously known quasi-critical charge density waves. They persist up to well above the pseudogap temperature T*, are characterized by energies of a few milli-electron volts, and pervade a large area of the phase diagram.

Gap suppression at a Lifshitz transition in a multi-condensate superconductor

In multi-orbital materials, superconductivity can exhibit several coupled condensates. In this context, quantum confinement in two-dimensional superconducting oxide interfaces offers new degrees of freedom to engineer the band structure and selectively control the occupancy of 3d orbitals by electrostatic doping. Here, we use resonant microwave transport to extract the superfluid stiffness of the (110)-oriented LaAlO₃/SrTiO₃ interface in the entire phase diagram. We provide evidence of a transition from single-condensate to two-condensate superconductivity driven by continuous and reversible electrostatic doping, which we relate to the Lifshitz transition between 3d bands based on numerical simulations of the quantum well. We find that the superconducting gap is suppressed while the second band is populated, challenging Bardeen-Cooper-Schrieffer theory. We ascribe this behaviour to the existence of superconducting order parameters with opposite signs in the two condensates due to repulsive coupling. Our findings offer an innovative perspective on the possibility to tune and control multiple-orbital physics in superconducting interfaces.

Exercise-based cardiac rehabilitation in patients with reduced left ventricular ejection fraction: The Cardiac Rehabilitation Outcome Study in Heart Failure (CROS-HF): A systematic review and meta-analysis

Background

In heart failure with reduced left ventricular ejection fraction (HFrEF) patients the effects of exercise-based cardiac rehabilitation on top of state-of-the-art pharmacological and device therapy on mortality, hospitalization, exercise capacity and quality-of-life are not well established.

Design

The design of this study involved a structured review and meta-analysis.

Methods

Evaluation of randomised controlled trials of exercise-based cardiac rehabilitation in HFrEF-patients with left ventricular ejection fraction ≤40% of any aetiology with a follow-up of ≥6 months published in 1999 or later.

Results

Out of 12,229 abstracts, 25 randomised controlled trials including 4481 HFrEF-patients were included in the final evaluation. Heterogeneity in study population, study design and exercise-based cardiac rehabilitation-intervention was evident. No significant difference in the effect of exercise-based cardiac rehabilitation on mortality compared to control-group was found (hazard ratio 0.75, 95% confidence interval 0.39–1.41, four studies; 12-months follow-up: relative risk 1.29, 95% confidence interval 0.66–2.49, eight studies; six-months follow-up: relative risk 0.91, 95% confidence interval 0.26–3.16, seven studies). In addition there was no significant difference between the groups with respect to ‘hospitalization-for-any-reason’ (12-months follow-up: relative risk 0.79, 95% confidence interval 0.41–1.53, four studies), or ‘hospitalization-due-to-heart-failure’ (12-months follow-up: relative risk 0.59, 95% confidence interval 0.12–2.91, four studies; six-months follow-up: relative risk 0.84, 95% confidence interval 0.07–9.71, three studies). All studies show improvement of exercise capacity. Participation in exercise-based cardiac rehabilitation significantly improved quality-of-life as evaluated with the Kansas City Cardiomyopathy Questionnaire: (six-months follow-up: mean difference 1.94, 95% confidence interval 0.35–3.56, two studies), but no significant results emerged for quality-of-life measured by the Minnesota Living with Heart Failure Questionnaire (nine-months or more follow-up: mean difference –4.19, 95% confidence interval –10.51–2.12, seven studies; six-months follow-up: mean difference –5.97, 95% confidence interval –16.17–4.23, four studies).

Conclusion

No association between exercise-based cardiac rehabilitation and mortality or hospitalisation could be observed in HFrEF patients but exercise-based cardiac rehabilitation is likely to improve exercise capacity and quality of life.

Paradoxical embolism with thrombus stuck in a patent foramen ovale: a review of treatment strategies

OBJECTIVE

Paradoxical embolism represents a rare condition occurring when a thrombus originating from venous system produces pulmonary embolism and systemic embolization through an intracardiac or pulmonary shunt. The evidence of a thrombus entrapped in a patent foramen ovale (PFO) is an even more rare condition. There is uncertainty about the optimal treatment strategy.

PATIENTS AND METHODS

A 58-year-old male patient was admitted to our Internal Medicine Unit with the diagnosis of bilateral bronchopneumonia. During hospitalization, the co-occurrence of chest pain and amaurosis led us to hypothesize a paradoxical embolism.

RESULTS

Transthoracic echocardiography showed the presence of a thrombus stuck over the interatrial septum. A contrast-enhanced chest CT scan showed multiple pulmonary embolisms and brain CT scan documented a hypodense area, of ischemic significance, in the left occipital lobe near tentorium. In order to prevent further embolization, emergency cardiac surgery (right atriotomy, removal of thrombus and closure of the PFO, pulmonary thrombectomy) was performed without complications.

CONCLUSIONS

Although rare, the evidence of a thrombus stuck in a patent foramen ovale represents a clinical emergency. The optimal therapeutic approach is still debated. The surgical correction seems to be a safe and effective option for these patients.

Re-entrant charge order in overdoped (Bi,Pb)2.12Sr1.88CuO6+δ outside the pseudogap regime

In the underdoped regime, the cuprate high-temperature superconductors exhibit a host of unusual collective phenomena, including unconventional spin and charge density modulations, Fermi surface reconstructions, and a pseudogap in various physical observables. Conversely, overdoped cuprates are generally regarded as conventional Fermi liquids possessing no collective electronic order. In partial contradiction to this widely held picture, we report resonant X-ray scattering measurements revealing incommensurate charge order reflections for overdoped (Bi,Pb)_2.12Sr_1.88CuO_6+δ (Bi2201), with correlation lengths of 40-60 lattice units, that persist up to temperatures of at least 250 K. The value of the charge order wavevector decreases with doping, in line with the extrapolation of the trend previously observed in underdoped Bi2201. In overdoped materials, however, charge order coexists with a single, unreconstructed Fermi surface without nesting or pseudogap features. The discovery of re-entrant charge order in Bi2201 thus calls for investigations in other cuprate families and for a reconsideration of theories that posit an essential relationship between these phenomena.

Competition between electron pairing and phase coherence in superconducting interfaces

In LaAlO3/SrTiO3 heterostructures, a gate tunable superconducting electron gas is confined in a quantum well at the interface between two insulating oxides. Remarkably, the gas coexists with both magnetism and strong Rashba spin-orbit coupling. However, both the origin of superconductivity and the nature of the transition to the normal state over the whole doping range remain elusive. Here we use resonant microwave transport to extract the superfluid stiffness and the superconducting gap energy of the LaAlO3/SrTiO3 interface as a function of carrier density. We show that the superconducting phase diagram of this system is controlled by the competition between electron pairing and phase coherence. The analysis of the superfluid density reveals that only a very small fraction of the electrons condenses into the superconducting state. We propose that this corresponds to the weak filling of high-energy dxz/dyz bands in the quantum well, more apt to host superconductivity.

Glue function of optimally and overdoped cuprates from inversion of the Raman spectra

We address the issue of identifying the mediators of effective interactions in cuprates superconductors. Specifically, we use inversion theory to analyze Raman spectra of optimally and over-doped La2-x Sr x CuO4 samples. This allows us to extract the so-called glue function without making any a priori assumption based on any specific model. We use instead two different techniques, namely the singular value decomposition and a multi-rectangle decomposition. With both techniques we find consistent results showing that: (i) two distinct excitations are responsible for the glue function, which have completely different doping dependence. One excitation becomes weak above optimal doping, where on the contrary the other keeps (or even slightly increases) its strength; (ii) there is a marked temperature dependence on the weight and spectral distribution of these excitations, which therefore must have a somewhat critical character. It is quite natural to identify and characterize these two distinct excitations as damped antiferromagnetic spin waves and damped charge density waves, respectively. This sets the stage for a scenario in which superconductivity is concomitant and competing with a charge ordering instability.

Phase Separation from Electron Confinement at Oxide Interfaces

Oxide heterostructures are of great interest for both fundamental and applicative reasons. In particular, the two-dimensional electron gas at the LaAlO_{3}/SrTiO_{3} or LaTiO_{3}/SrTiO_{3} interfaces displays many different properties and functionalities. However, there are clear experimental indications that the interface electronic state is strongly inhomogeneous and therefore it is crucial to investigate possible intrinsic mechanisms underlying this inhomogeneity. Here, the electrostatic potential confining the electron gas at the interface is calculated self-consistently, finding that such confinement may induce phase separation, to avoid a thermodynamically unstable state with a negative compressibility. This provides a robust mechanism for the inhomogeneous character of these interfaces.

Interplay between density and superconducting quantum critical fluctuations

We consider the case of a density-driven metal-superconductor transition in the proximity of an electronic phase separation. In particular, we investigate the interplay between superconducting fluctuations and density fluctuations, which become quantum critical when the electronic phase separation vanishes at zero temperature into a quantum critical point. In this situation, the critical dynamical density fluctuations strongly affect the dynamics of the Cooper-pair fluctuations, which acquire a more singular character with a z  =  3 dynamical critical index. This gives rise to a scenario that possibly rules the disappearance of superconductivity when the electron density is reduced by electrostatic gating at the LaAlO3/SrTiO3 interface.

Field-effect control of superconductivity and Rashba spin-orbit coupling in top-gated LaAlO3/SrTiO3 devices

The recent development in the fabrication of artificial oxide heterostructures opens new avenues in the field of quantum materials by enabling the manipulation of the charge, spin and orbital degrees of freedom. In this context, the discovery of two-dimensional electron gases (2-DEGs) at LaAlO₃/SrTiO₃ interfaces, which exhibit both superconductivity and strong Rashba spin-orbit coupling (SOC), represents a major breakthrough. Here, we report on the realisation of a field-effect LaAlO₃/SrTiO₃ device, whose physical properties, including superconductivity and SOC, can be tuned over a wide range by a top-gate voltage. We derive a phase diagram, which emphasises a field-effect-induced superconductor-to-insulator quantum phase transition. Magneto-transport measurements show that the Rashba coupling constant increases linearly with the interfacial electric field. Our results pave the way for the realisation of mesoscopic devices, where these two properties can be manipulated on a local scale by means of top-gates.

Multiple quantum criticality in a two-dimensional superconductor

The diverse phenomena associated with the two-dimensional electron gas (2DEG) that occurs at oxide interfaces include, among others, exceptional carrier mobilities, magnetism and superconductivity. Although these have mostly been the focus of interest for potential future applications, they also offer an opportunity for studying more fundamental quantum many-body effects. Here, we examine the magnetic-field-driven quantum phase transition that occurs in electrostatically gated superconducting LaTiO3/SrTiO3 interfaces. Through a finite-size scaling analysis, we show that it belongs to the (2+1)D XY model universality class. The system can be described as a disordered array of superconducting puddles coupled by a 2DEG and, depending on its conductance, the observed critical behaviour is single (corresponding to the long-range phase coherence in the whole array) or double (one related to local phase coherence, the other one to the array). A phase diagram illustrating the dependence of the critical field on the 2DEG conductance is constructed, and shown to agree with theoretical proposals. Moreover, by retrieving the coherence-length critical exponent ν, we show that the quantum critical behaviour can be clean or dirty according to the Harris criterion, depending on whether the phase-coherence length is smaller or larger than the size of the puddles.

Intrinsic instability of electronic interfaces with strong Rashba coupling

We consider a model for the two-dimensional electron gas formed at the interface of oxide heterostructures, which includes a Rashba spin-orbit coupling proportional to the electric field perpendicular to the interface. Based on the standard mechanism of polarity catastrophe, we assume that the electric field has a contribution proportional to the electron density. Under these simple and general assumptions, we show that a phase separation instability (signaled by a negative compressibility) occurs for realistic values of the spin-orbit coupling and of the electronic band-structure parameters. This provides an intrinsic mechanism for the inhomogeneous phases observed at the LaAlO(3)/SrTiO(3) or LaTiO(3)/SrTiO(3) interfaces.

Concomitant evaluation of flow-mediated vasodilation and epicardial fat thickness in idiopathic deep venous thrombosis

Flow mediated vasodilation (FMD) evaluates the endothelium-dependent vasodilation, is a reliable marker of arterial endothelial dysfunction and is related to coronary artery disease. Visceral fat predicts an unfavorable cardiovascular and metabolic risk profile in humans and echocardiographic assessment of epicardial fat (EF) is a reliable marker of visceral adiposity. We measured the FMD and EF thickness in 77 subjects, 38 without idiopathic deep vein thrombosis (DVT) (mean age 65.95 ± 16.29 years) and 39 with idiopathic DVT (mean age 65.49 ± 17.22 years). The purpose of this work is to investigate the presence of statistical association between FMD and DVT and between EF thickness and DVT. Furthermore, to account for possible atherosclerosis risk factor unbalances, comparison between FMD and DVT (and between EF and DVT) was assessed using a multivariate logistic regression model which included the following covariates: FMD, EF, age, sex, smoking and the presence of obesity. Subjects without DVT showed significant lower values of EF thickness (9.07 ± 1.89 mm vs 12.32 ± 1.73 mm, p=0.005) and borderline-significant greater values of FMD (9.01 ± 2.77 percent vs 7.47 ± 5.37 percent, p=0.058) as compared to those with DVT. In conclusion, the data presented indicate that subjects affected by spontaneous deep vein thrombosis may have an impaired endothelium-dependent vasodilation, a marker of arterial endothelial dysfunction related to coronary artery disease, and an increased epicardial adipose tissue, a marker of cardiometabolic risk.

Arterial endothelial dysfunction and idiopathic deep venous thrombosis

Recent epidemiological studies have highlighted higher risk of subsequent development of atherosclerotic disease in patients with deep venous thrombosis (DVT). We evaluated the Flow Mediated Dilation (FMD) looking for arterial endothelial dysfunction, predictive for future ischaemic cardiovascular events, in patients with idiopathic DVT. FMD was measured in the brachial artery in 60 subjects with idiopathic DVT (age 60.1±17.4) and in 60 subjects without idiopathic DVT (age 61.2±15.1), with a similar cardiovascular risk factor profile. DVT patients showed lower FMD (6.78%±5.53% vs 10.88±3.31%, p<0.001). Univariate linear models showed that obesity (p=0.010), dyslipidemia (p=0.004), arterial hypertension (p=0.046), use of platelet anti-aggregating agents (p=0.018) and DVT (p<0.001) were associated to lower levels of FMD. In multivariate linear model, only DVT (p<0.001) remained an independent predictor of lower levels of FMD. Furthermore, an 8.5% cut-off value of FMD was chosen in a ROC curve analysis. Values of FMD ≤ 8.5% were more frequent in DVT patients (71.67% vs 41.67%, p<0.001). Univariate logistic regression models showed that dyslipidemia (p=0.008), use of platelet anti-aggregating agents (p=0.004) and DVT (p<0.001) were associated to a higher risk of having FMD ≤ 8.5%. Multivariate logistic regression model showed that DVT was the unique independent predictor for FMD ≤ 8.5% (p<0.001). In conclusion, DVT patients more frequently have impaired FMD, recognized as an indicator of arterial endothelial dysfunction and a marker for increased cardiovascular risk.

Pre-synaptic nicotinic receptors evoke endogenous glutamate and aspartate release from hippocampal synaptosomes by way of distinct coupling mechanisms

BACKGROUND AND PURPOSE

The present work aimed to investigate whether and through which mechanisms selective α7 and α4β2 nicotinic receptor (nAChR) agonists stimulate endogenous glutamate (GLU) and aspartate (ASP) release in rat hippocampus.

EXPERIMENTAL APPROACH

Rat hippocampal synaptosomes were purified on Percoll gradients and superfused in vitro to study endogenous GLU and ASP release. The synaptosomes were superfused with selective α7 and α4β2 nAChR agonists and antagonists. The excitatory amino acid (EAA) content of the samples of superfusate was determined by HPLC after pre-column derivatization and separation on a chromatographic column coupled with fluorimetric detection.

KEY RESULTS

Choline (Ch), a selective α7 receptor agonist, elicited a significant release of both GLU and ASP which was blocked by the α7 receptor antagonist methyllycaconitine (MLA), but was unaltered by the α4β2 receptor antagonist dihydro-β-erythroidine (DHβE). The stimulant effect of Ch was strongly reduced in a Ca(2+) -free medium, was not inhibited by Cd(2+) and tetrodotoxin (TTX), but was antagonized by dantrolene, xestospongin C and thapsigargin. 5-Iodo-A-85380 dihydrochloride (5IA85380), a selective α4β2 receptor agonist, elicited EAA release in a DHβE-sensitive, MLA-insensitive fashion. The 5IA85380-evoked release was dependent on extracellular Ca(2+) , blocked by Cd(2+) and TTX, but unaffected by dantrolene.

CONCLUSIONS AND IMPLICATIONS

Our study shows for the first time that rat hippocampal synaptosomes possess α7 and α4β2 nAChR subtypes, which can enhance the release of endogenous GLU and ASP via two distinct mechanisms of action. These results extend our knowledge of the nicotinic modulation of excitatory synaptic transmission in the hippocampus.

Specific inhibitory effect of amyloid-beta on presynaptic muscarinic receptor subtypes modulating neurotransmitter release in the rat nucleus accumbens

In this study we investigate on the effect of amyloid-beta1-40 (A beta 1-40) on the oxotremorine (OXO)-induced release of [(3)H] dopamine (DA), [(3)H]GABA and [(3)H]acetylcholine (ACh) from synaptosomes in the rat nucleus accumbens (NAc). OXO in presence of himbacine (HIMBA) was able to increase the basal release of [(3)H]GABA. The OXO-elicited [(3)H]GABA overflow was significantly antagonized by atropine (A; 94%), by the M3 antagonists DAU5884 (96%) and 4-DAMP (70%), and by A beta 1-40 (65%). Exposure of NAc synaptosomes to OXO produced a dose-dependent increase of [(3)H]DA overflow which was antagonized by A, partially inhibited by A beta 1-40 (100 nM) but unaffected by DAU5884 and 4-DAMP. The K(+)-evoked [(3)H]ACh overflow was inhibited by OXO. This effect was counteracted by the M2 antagonist AFDX-116 but not by the selective M4 antagonist mamba toxin 3 (MT3). The K(+)-evoked [(3)H]GABA overflow was also inhibited by OXO but conversely, this effect was counteracted by MT3 and not by AFDX-116. A beta 1-40 (100 nM) did not modify the inhibitory effect of OXO both on the K(+)-evoked [(3)H]ACh and [(3)H]GABA overflow. The results show that in the rat NAc, A beta 1-40 selectively inhibits the function of the muscarinic subtypes which stimulate neurotransmitter release and not those which modulate negatively the stimulated release.

Model of quasiparticles coupled to a frequency-dependent charge-density-wave order parameter in cuprate superconductors

We investigate a model where superconducting electrons are coupled to a frequency dependent charge-density wave order parameter Delta_{r}(omega). Our approach can reconcile the simultaneous existence of low-energy Bogoljubov quasiparticles and high energy electronic order as observed in scanning tunneling microscopy (STM) experiments. The theory accounts for the contrast reversal in the STM spectra between positive and negative bias observed above the pairing gap. An intrinsic relation between scattering rate and inhomogeneities follows naturally.

Competing orders in FeAs layers

Using the unrestricted Hartree-Fock approximation and Landau theory we identify possible phases competing with superconductivity in FeAs layers. We find that close to half-filling the transition from the paramagnet to the magnetically ordered phase is first order, making anharmonicities relevant and leading to a rich phase diagram. Between the already known one-dimensionally modulated magnetic stripe phase and the paramagnet we find a new phase which has the same structure factor as the former but in which magnetic moments at nearest-neighbor sites are at right angles making electrons acquire a nontrivial phase when circulating a plaquette at strong coupling. Another competing phase has magnetic and charge order and may be stabilized by charged impurities.

Modulation of the function of presynaptic alpha7 and non-alpha7 nicotinic receptors by the tryptophan metabolites, 5-hydroxyindole and kynurenate in mouse brain

BACKGROUND AND PURPOSE

Two metabolites of tryptophan, 5-hydroxyindole and kynurenic acid (kynurenate) affect the function of alpha7 nicotinic acetylcholine receptors (nAChRs), as measured by electrophysiological and Ca2+ fluorescence techniques. To better understand the modulations by 5-hydroxyindole and kynurenate of the function of nAChR subtypes, we compared the effects of 5-hydroxyindole and kynurenate on the release of various transmitters evoked by nAChR activation.

EXPERIMENTAL APPROACH

The function of alpha7nAChRs located on glutamatergic terminals was investigated by monitoring the release of [3H]D-aspartate or of endogenous glutamate from neocortical synaptosomes. We also comparatively considered non-alpha7 release-enhancing nAChRs localized on hippocampal noradrenergic or cholinergic terminals, as well as on striatal dopaminergic terminals.

KEY RESULTS

Epibatidine or nicotine, inactive on their own on basal release, enhanced [3H]D- aspartate and glutamate efflux in presence of 5-hydroxyindole. The release evoked by nicotine plus 5-hydroxyindole was abolished by methyllycaconitine or alpha-bungarotoxin. Presynaptic nAChRs mediating the release of [3H]noradrenaline ([3H]NA), [3H]dopamine ([3H]DA), or [3H]ACh were inhibited by 5-OHi. The alpha7nAChR-mediated release of [3H]D-aspartate was reduced by kynurenate at concentrations unable to affect the non-alpha7 receptor-mediated release of tritiated NA, DA or ACh.

CONCLUSIONS AND IMPLICATIONS

(i) 5-hydroxyindole permits selective activation of alpha7nAChRs mediating glutamate release; (ii) kynurenate down-regulates the permissive role of 5-hydroxyindole on alpha7nAChR activation; (iii) the non-alpha7nAChRs mediating release of NA, DA or ACh can be inhibited by 5-hydroxyindole, but not by kynurenate. These findings suggest up the possibility of developing novel drugs able to modulate selectively the cholinergic-glutamatergic transmission.

Charge-fluctuation contribution to the Raman response in superconducting cuprates

We calculate the Raman response contribution due to soft collective modes, finding a strong dependence on the photon polarizations and on the characteristic wave vectors of the modes. We compare our results with recent Raman spectroscopy experiments in underdoped cuprates, La2-xSrxCuO4 and (Y1.97Ca0.3)Ba2CuO6.05, where anomalous low-energy peaks are observed, which soften upon lowering the temperature. We show that the specific dependence on doping and on photon polarizations of these peaks can naturally arise from charge collective excitations at finite wavelength.

Electron-phonon interaction close to a Mott transition

The effect of Holstein electron-phonon interaction on a Hubbard model close to a Mott-Hubbard transition at half filling is investigated by means of dynamical mean-field theory. We observe a reduction of the effective mass that we interpret in terms of a reduced effective repulsion. When the repulsion is rescaled to take into account this effect, the quasiparticle low-energy features are unaffected by the electron-phonon interaction. Phonon features are only observed within the high-energy Hubbard bands. The lack of electron-phonon fingerprints in the quasiparticle physics can be explained interpreting the quasiparticle motion in terms of rare fast processes.

Phase separation close to the density-driven Mott transition in the Hubbard-Holstein model

The density-driven Mott transition is studied by means of dynamical mean-field theory in the Hubbard-Holstein model, where the Hubbard term leading to the Mott transition is supplemented by an electron-phonon (e-ph) term. We show that an intermediate e-ph coupling leads to a first-order transition at T=0, which is accompanied by a phase separation between a metal and an insulator. The compressibility in the metallic phase is substantially enhanced. At quite larger values of the coupling, a polaronic phase emerges coexisting with a nonpolaronic metal.

Immune system alterations in lung cancer patients

The immune system plays an important role in the defense against neoplastic disease and immune responses show temporal changes related to circadian variations of antibodies, total lymphocytes in the peripheral blood and cell mediated immune responses. In this study we evaluate. lymphocyte subpopulations and interleukin-2 (IL-2) serum levels in peripheral blood samples collected at four-hour intervals for 24-hours starting at 06.00 h from ten healthy subjects aged 65-79 years (mean age +/- s.e. 67.28 +/- 3.11) and from ten subjects suffering from untreated non small cell lung cancer aged 65-78 years (mean age +/- s.e. 68.57 +/- 1.81). Areas under the curve, mean diurnal levels (mean of 06.00-10.00-14.00 h) and mean nocturnal levels (mean of 18.00-22.00-02.00 h) were calculated, and the presence of circadian rhythmicity was evaluate. When we compared AUC values there was a decrease in CD8bright (T suppressor subset) and an increase in CD16 (natural killer cells) and of IL-2 serum levels in cancer patients. When we compared mean diurnal levels, CD8 (T suppressor/cytotoxic subset) and CD8bright levels were lower, and CD16 levels were higher in cancer patients. When we compared mean nocturnal levels, CD16 and CD25 (T and B activated lymphocytes with expression of the a chain of IL-2 receptor) levels were higher, while CD8, CD8bright, CD20 (total B-cells), TcRd1 (epitope of the constant domain of d chain of T-cell receptor 1) and dTcS1 (epitope of the variable domain of d chain of T-cell receptor1) levels were lower in cancer patients. A clear circadian rhythm was validated for the time-qualified changes in CD4, CD20, HLA-DR with acrophase at night, and CD8, CD8 bright, CD8 dim, CD16, TcRd1 and dTcS1 with acrophase in the morning in the control group. A clear circadian rhythm was validated for the time-qualified changes in CD4 with acrophase at night, in the group of cancer patients. Results obtained in our study show that lung cancer is associated with anomalies of proportion and circadian variations of lymphocyte subsets that must be considered when adoptive immunotherapy has to be planned.

[Case report: Acro-necrosis of the upper limbs caused by gemcitabine therapy]

INTRODUCTION

Even if infrequent, a digital necrosis after chemotherapy can occur in cancer patients. The gemcitabine is generally well tolerate; the cutaneous toxic ulcerations only in 0.3% of the cases induces the suspension of the treatment.

CLINICAL CASE

A 70 year old patient, female, with a bladder cancer, after a trans-urethral resection, is submitted to adjuvant chemotherapy with Gemcitabine 1700 mg (total dose/die), with administration in the days 1st and 8th, while in the 15th day was not effected because, to distance of 3-4 days from the second administration, appear paresthesies of the fingers of the hands, together with Raynaud type phenomenon, 38-39 degrees C intermittent fever, digital necrosis and fingertips gangrene. Laboratory: (Normal): RF; AutoAb: AMA, ASMA, APCA, anti-DNA; ENA; lupus anti-coagulant; Ab-anti-cardiolipin; C3-C4, CIC; homocysteine, anti-thrombin, protein C, protein S, mutation of the factor V of Leiden, plasminogen, alfa 2-antiplasmin. (Altered): Auto-antibody: ANA (on Hep-2): positive (title 1/160, speckled pattern), cryoglobulin positive, ESR 29; Instrumental examinations: Superior Limbs Angiograpy: Occlusion of the digital arteries proper of 2nd, 3rd and 4th finger of the hands. Electromyography Inferior Arts: normal. Superior Arts: bilateral suffering of the median nerve at the carpal tunnel. Biopsy of the hand cutis: Hyperkeratosis, acanthosis and papillomatosis of the skin. Arterial vases with signs of endothelioangiitis and aspecific inflammation.

CONCLUSIONS

Even if acronecrosis of the superior limbs is a rare effect of the gemcitabine, we would recommend particular caution in the administration of this drug in patient with known autoimmune disorders.

Screening for silent myocardial ischaemia in type 2 diabetic patients with additional atherogenic risk factors: applicability and accuracy of the exercise stress test

OBJECTIVE

Coronary artery disease (CAD), a major cause of mortality in patients with type 2 diabetes (T2D), is often diagnosed late because of silent myocardial ischaemia (SMI). Exercise electrocardiogram testing (ECG) stress is the most utilized screening test for SMI. Its applicability and accuracy, which have never been reported in asymptomatic high-risk T2D patients, have been investigated in this study.

DESIGN

A cross-sectional study with coronary angiography as the gold standard for detecting CAD was used.

METHODS

Two hundred and six consecutive T2D patients, without symptoms and resting ECG signs of ischaemia but with peripheral vascular disease (PVD) and/or > or = two atherogenic factors, were studied. Ischaemia at ECG stress was indicated by horizontal or downsloping ST segment depression > or =1 mm at 0.08 s after the J point. CAD was defined by stenosis > or =70%.

RESULTS

Only 141/206 (68%) patients had a diagnostic test: 27 (19%) tested positive and 114 (81%) tested negative. Coronary angiography in 71 patients (the 27 who tested positive and 44 randomly selected patients who tested negative) indicated a CAD prevalence of 29% and the ECG stress accuracy was 79%. 'False negative' patients (18%) had a higher prevalence (P<0.01) of long duration of diabetes and PVD.

CONCLUSIONS

This is the first study which provides insights into the applicability and accuracy of ECG stress in screening SMI in high-risk patients with T2D. Due to the high prevalence of CAD, alternative screening tests in patients unable to perform the test and in those with a high chance of being 'false negative' should be looked for and validated.

Anomalous optical absorption in the normal state of overdoped cuprates near the charge-ordering instability

We argue that the hump observed in the optical conductivity at or below a few hundreds of cm(-1), in overdoped cuprates such as the electron-doped Nd(2-x)Ce(x)CuO(4-y) at x > or approximately equal to 0.15 and the hole-doped Bi2Sr2CuO6 and La2-xSrxCuO4, cannot be accounted for within a single-fluid description. We propose instead an interpretation based on the direct excitation of charge collective modes, which become nearly critical in the proximity to a charge-ordering instability. Their critical character entails a peculiar temperature dependence and a pseudoscaling form of the optical spectra, which agree with the experimental data.

First-order pairing transition and single-particle spectral function in the attractive hubbard model

A dynamical mean-field theory analysis of the attractive Hubbard model in the normal phase is carried out upon restricting to solutions where superconducting order is not allowed. A clear first-order pairing transition as a function of the coupling takes place at all the electron densities out of half filling between a Fermi liquid, stable for U<U(c), and an insulating bound pairs phase for U>U(c), and it is accompanied by phase separation. The spectral function in the metallic phase is constituted by a low-energy structure around the Fermi level, which disappears discontinuously at U = U(c), and two high-energy features (Hubbard bands), which persist in the insulating phase.

Anomalous isotopic effect near the charge-ordering quantum criticality

Within the Hubbard-Holstein model, we evaluate the crossover lines marking the opening of pseudogaps in the cuprates, which, in our scenario, are ruled by the proximity to a charge-ordering quantum criticality (stripe formation). We find that their isotopic dependence, due to critical fluctuations, implies a substantial positive shift of the pseudogap-formation temperature T(*). We infer that the isotopic shift of the superconducting T(c) is nearly absent in the optimally and overdoped regimes and is negative and increasing upon underdoping. The dynamical nature of the charge-ordering transition may explain the spread of the experimental values of T(*).

Early-onset amyloid deposition and cognitive deficits in transgenic mice expressing a double mutant form of amyloid precursor protein 695

We have created early-onset transgenic (Tg) models by exploiting the synergistic effects of familial Alzheimer's disease mutations on amyloid beta-peptide (Abeta) biogenesis. TgCRND8 mice encode a double mutant form of amyloid precursor protein 695 (KM670/671NL+V717F) under the control of the PrP gene promoter. Thioflavine S-positive Abeta amyloid deposits are present at 3 months, with dense-cored plaques and neuritic pathology evident from 5 months of age. TgCRND8 mice exhibit 3,200-4,600 pmol of Abeta42 per g brain at age 6 months, with an excess of Abeta42 over Abeta40. High level production of the pathogenic Abeta42 form of Abeta peptide was associated with an early impairment in TgCRND8 mice in acquisition and learning reversal in the reference memory version of the Morris water maze, present by 3 months of age. Notably, learning impairment in young mice was offset by immunization against Abeta42 (Janus, C., Pearson, J., McLaurin, J., Mathews, P. M., Jiang, Y., Schmidt, S. D., Chishti, M. A., Horne, P., Heslin, D., French, J., Mount, H. T. J., Nixon, R. A., Mercken, M., Bergeron, C., Fraser, P. E., St. George-Hyslop, P., and Westaway, D. (2000) Nature 408, 979-982). Amyloid deposition in TgCRND8 mice was enhanced by the expression of presenilin 1 transgenes including familial Alzheimer's disease mutations; for mice also expressing a M146L+L286V presenilin 1 transgene, amyloid deposits were apparent by 1 month of age. The Tg mice described here suggest a potential to investigate aspects of Alzheimer's disease pathogenesis, prophylaxis, and therapy within short time frames.

Induction of p53 in the glutamate-induced cell death program

Fifteen minute exposure of primary cultures of cerebellar granule cells to micromolar concentrations of glutamate results in apoptotic cell death. Among the intracellular events triggered by glutamate, we identified two transcriptional factors, i.e. the p50 member of the NF-kappaB family and the tumor suppressor phosphoprotein p53, that are apparently linked by a sequential trascriptional program. We found that pretreatment of the cultures with aspirin (ASA), which inhibits NF-kappaB activation, resulted in a complete prevention of glutamate-induced p53 immunoreactivity. The same results were obtained pretreating the cells with a specific p53 antisense oligonucleotide. Both ASA and p53 antisense abolished glutamate-induced apoptosis. We also found that two other proteins, the cyclin dependent kinase inhibitor p21 and DNA mismatches repair MSH2, whose encoding genes are well known target of p53, were upregulated by glutamate. On these bases, we propose NF-kappaB, p53, p21 and MSH2 as relevant contributors of the glutamate-induced pro-apoptotic pathway.

Presenilin-1 regulates the neuronal threshold to excitotoxicity both physiologically and pathologically

A direct pathophysiological role of Familial Alzheimer's Disease (FAD)-associated Presenilin 1 (PS1) mutations in neuronal vulnerability remains a controversial matter. We evaluated the relationship between PS1 and excitotoxicity in four different experimental models of neurotoxicity by using primary neurons from (i) transgenic (tg) mice overexpressing a human FAD-linked PS1 variant (L286V mutation), (ii) tg mice overexpressing human wild-type (wt) PS1, (iii) PS1 knockout mice, and (iv) wt mice in which PS1 gene expression was knocked down by antisense treatment. We found that primary neurons overexpressing mutated PS1 showed an increased vulnerability to both excitotoxic and hypoxic-hypoglycemic damage when compared with neurons obtained from either mice overexpressing human wt PS1 or in wt mice. In addition, reduced excitotoxic damage was obtained in neurons in which PS1 expression was absent or diminished. Data obtained in in vivo experimental models of excitotoxicity partially supported the in vitro observations. Accelerated neuronal death was demonstrated in the hippocampus of mice overexpressing mutated PS1 after peripheral administration of kainic acid in comparison with wt animals. However, measurement of the infarct volume after middle cerebral artery occlusion did not show significant difference between the two animal groups. The results altogether suggest that expression of FAD-linked PS1 variants increases the vulnerability of neurons to a specific type of damage in which excitotoxicity plays a relevant role. In addition, they support the view that reduction of endogenous PS1 expression results in neuroprotection.

Interleukin-10 modulates neuronal threshold of vulnerability to ischaemic damage

Interleukin-10 (IL-10) is a powerful suppressor of cellular immune responses, with a postulated role in brain inflammation. First, we have evaluated the role of this cytokine in ischaemic brain damage using IL-10 knockout (IL-10-/-) mice. The middle cerebral artery (MCA) was occluded in either IL-10-/- or wild-type animals of corresponding strain (C57Bl/6) and age. Infarct volume was assessed 24 h later in serial brain sections. Brain infarct produced by MCA occlusion was 30% larger in the IL-10-/- than in wild-type mice (21. 8 +/- 1.2 vs. 16.9 +/- 1.0 mm3, respectively; P < 0.01; Student's t-test). To further characterize these findings, studies were extended to in vitro models. Primary neuronal cortical cultures derived from IL-10-/- animals were more susceptible to both excitotoxicity and combined oxygen-glucose deprivation compared with cell cultures from wild-type mice. Moreover, when added to the culture medium, recombinant murine IL-10 (0.1-100 ng/mL) exerted a concentration-dependent prevention of neuronal damage induced by excitotoxicity in both cortical and cerebellar granule cell cultures taken from either strain. The accordance of in vivo and in vitro data allows us to suggest a potential neuroprotective role of IL-10 against cerebral ischaemia when administered exogenously or made available from endogenous sources.

Contribution of NF-kappaB and p53 in the glutamate-induced apoptosis

Exposure of primary cultures of cerebellar granule cells for 15 min to micromolar concentrations of glutamate results in cell death of both necrotic and apoptotic types. Among the intracellular events triggered by glutamate, we identified two transcriptional factors: the p50 member of the NF-kappaB family and the tumor suppressor phosphoprotein p53. Pretreatment of the cultures with aspirin, which inhibits NF-kappaB activation, or with specific p53 antisense oligonucleotide, which inhibits p53 transcription, resulted in a complete prevention of glutamate-induced p53 induction and apoptosis. These findings suggest the existence of a transcriptional program activated by glutamate receptor stimulation in which p50 and p53 play a relevant role. Then, we studied the expression of two p53 downstream genes that could participate in the glutamate-induced pro-apoptotic pathway: p21, which codes for an inhibitor of different cyclin dependent kinases, and MSH2, which codes for a protein involved in the recognition and repair of DNA mismatches. We found that primary cerebellar neurons expressed p21 and MSH2 at very low levels in basal conditions. However, very soon after a brief exposure of the cells to glutamate, the expression of both proteins was dramatically enhanced.On these bases, we propose NF-kappaB, p53, p21 and MSH2 as relevant contributors of the glutamate-induced pro-apoptotic pathway. Understanding this cascade of nuclear events may unravel specific targets for pharmacological intervention for those neurological diseases in which excitatory amino acid-induced apoptosis plays a relevant role.

Stripe formation in electron-doped cuprates

We investigate the formation of charge domain walls in an electron-doped extended Hubbard model for the superconducting cuprates. Within an unrestricted Hartree-Fock approach, extended by slave bosons to obtain a better treatment of strong correlations, we demonstrate the occurrence of stripes in the (1,1) and (1,-1) directions having one doped electron per stripe site. The different filling, direction, and width of these electron-doped stripes with respect to those obtained in the hole-doped systems have interesting observable consequences.

Possible role of NF-kappaB and p53 in the glutamate-induced pro-apoptotic neuronal pathway

Apoptosis is now recognized as an important component in many progressive and acute neurodegenerative diseases. Extracellular signals and intracellular mechanisms triggering and regulating apoptosis in neuronal cells are still a matter of investigation. Here we review data from our and other laboratories with the aim to elucidate the nature of some proteins which are known to be involved in cell cycle regulation as well as in promoting degeneration and apoptosis of neurons. The following molecules will be taken into consideration: NF-kappaB, p53, p21 and MSH2. These proteins are activated by neurotoxic experimental conditions which involve the stimulation of selective receptors for the excitatory aminoacid glutamate. Thus, we hypothesize their contribution to an intracellular pathway responsible for the glutamate-induced neuronal death. Identification of such mechanisms could be relevant for understanding the apoptosis associated with various neurodegenerative diseases as well as for developing novel strategies of pharmacological intervention.

Nuclear factor-kappaB/Rel proteins: a point of convergence of signalling pathways relevant in neuronal function and dysfunction

Nuclear factor-kappaB (NF-kappaB)/Rel designates a family of transcription factors participating in the activation of a wide range of genes crucially involved in immune and inflammatory function. NF-kappaB/Rel proteins have been demonstrated recently in primary neurons and in several brain areas. Functional significance of these proteins is still not understood completely, but since certain subsets of neurons appear to contain constitutively active DNA-binding activity, it seems likely that they may participate in normal brain function. A growing body of evidence is accumulating for a specific activation of NF-kappaB/Rel proteins in the CNS, and in particular in neuronal cells, during neurodegenerative processes associated to etiologically unrelated conditions. Whether NF-kappaB activation is part of the neurodegenerative process or of protective mechanisms is a matter of debate. This issue will be reviewed here with particular attention to the available reports on the activity of NF-kappaB/Rel proteins in both experimental paradigms of neurodegeneration and post-mortem brain tissue of patients affected by various neurological diseases. We hypothesize that NF-kappaB/Rel proteins may represent the point of convergence of several signalling pathways relevant for initiating or accelerating the process of neuronal dysfunction and degeneration in many neurological diseases, including Parkinson's disease, Alzheimer's disease, CNS viral infections, and possibly others. If NF-kappaB/Rel proteins represent an integrating point of several pathways potentially contributing to neuronal degeneration, molecules that finely modulate their activity could represent a novel pharmacological approach to several neurological diseases.

Metoclopramide and domperidone block the antihypertensive effect of bromocriptine in hypertensive patients

This study was conducted in normotensive and hypertensive subjects at the Vargas Hospital of Caracas. Normotensive subjects received, in a cross-over fashion, placebo, metoclopramide (MTC), or domperidone (DOMP), 40 mg of each drug, daily for 1 week. The first group of patients under placebo for 1 week received a single 2.5-mg oral dose of bromocriptine (Br). The second group of patients received 30 mg MTC daily (divided into three doses) for 1 week. At the end of the period a single dose of 2.5 mg Br was administered to each patient. The third group of eight hypertensive patients received DOMP for 1 week at 30 mg/d and then a single 2.5-mg Br dose. Cardiovascular and biochemical parameters including arterial pressure, heart rate, plasma renin activity, and plasma aldosterone were evaluated during the 6-hour period before and after the administration of Br. Neither DOMP nor MTC significantly modified blood pressure and heart rate in normotensive patients. Br reduced both systolic and diastolic arterial pressure in hypertensive subjects. The peak of the antihypertensive effect appeared 3 hours after drug administration, but reduction of arterial pressure lasted approximately 6 hours. At the same time, Br reduced plasma aldosterone levels and plasma renin activity. MTC and DOMP reversed the antihypertensive effect of Br and its effect on aldosterone levels and plasma renin activity. We conclude from these findings that Br acts as an antihypertensive agent at peripheral and central levels by stimulating dopamine-2 receptors, which are involved in the aldosterone and renin secretion.

Induction of tumour-suppressor phosphoprotein p53 in the apoptosis of cultured rat cerebellar neurones triggered by excitatory amino acids

We found that primary cultures of rat cerebellar granule cells, although definitely postmitotic and terminally differentiated, express the tumour-suppressor phosphoprotein p53. In particular, granule cells both expressed significant levels of p53 mRNA and positively reacted to an anti-p53 antibody, from the first day of culturing. During neurone differentiation, p53 mRNA content did not significantly change, at least up to 12 days in vitro, while p53 immunoreactivity increased gradually. p53 expression appeared to be further modulable being upregulated after stimulation of glutamate ionotropic receptors by glutamate or kainate. Although qualitatively similar, p53 induction by glutamate and kainate differed in terms of intensity and time-course. The glutamate increase of p53 immunoreactivity appeared within 30 min after the treatment and lasted for at least 2 h. Kainate-induced increase of p53 immunoreactivity was delayed, becoming apparent within 2 h and lasting for at least 8 h. Both kainate- and glutamate-induced increases of p53 immunoreactivity were prevented by the non-competitive NMDA receptor antagonist MK 801. As shown by the electrophoretic mobility shift analysis, both glutamate and kainate induced increases of p53 DNA binding activity. Blockade of p53 induction by a specific p53 antisense oligonucleotide resulted in a partial reduction of excitotoxicity with a complete inhibition of the excitatory amino acids induced apoptosis. Our data suggest that stimulation of ionotropic glutamate receptors in neurones results in a p53-dependent apoptosis.

Priming of cultured neurons with sabeluzole results in long-lasting inhibition of neurotoxin-induced tau expression and cell death

Sabeluzole was described to have antiischemic, antiepileptic, and cognitive-enhancing properties, and is currently under development for Alzheimer's disease. Recently, it was reported that repeated treatments with sabeluzole protect cultured rat hippocampal neurons against NMDA- and glutamate-induced neurotoxicity. We evaluated the possibility that sabeluzole elicits neuroprotection by acting, either directly or indirectly, on tau proteins. We found that repeated treatments during development of primary cultures of cerebellar granule cells with nanomolar concentrations of sabeluzole resulted in mature cells that were resistant to the excitotoxicity induced by glutamate. Also, sabeluzole treatment specifically prevented the glutamate-induced increase of tau expression without modifying the basal pattern of expression of tau proteins, as shown by measurement of mRNA and protein levels. In human neuroblastoma cell line SH-SY5Y, differentiated by treatment with retinoic acid, doxorubicin increased tau immunoreactivity, and later induced cell death. Both effects were prevented by sabeluzole. Our data indicate that increased tau expression is a common response to different types of cells to neurotoxic agents, and that sabeluzole-induced neuroprotection is functionally associated with the prevention of the injury-mediated increase of tau expression.

Regulation of mouse neuropeptide Y Y1 receptor gene transcription: a potential role for nuclear factor-kappa B/Rel proteins

We previously isolated a 1.3-kb genomic fragment in the 5'-flanking region of the murine neuropeptide Y (NPY) Y1 receptor gene, which is able to drive the expression of LacZ reporter gene in neuronal cells. We determined the ability of deletion mutants of this region to modulate transcription of the heterologous luciferase gene in the Y1 receptor-expressing neuroblastoma/ glioma NG108-15 cells and the Y1 receptor-deficient 293 cells. Results suggest the presence of a cell type-specific core promoter (-399 to -218 from the initiator ATG) and, upstream, of two positive and two negative regulatory elements. Sequence analysis of the Y1 receptor promoter identified two decameric sequences corresponding to consensus binding sites for nuclear factor-kappa B/Rel proteins. Gel shift analysis indicated that a 29-bp oligonucleotide comprising the two putative kappa B sites, which we refer to as Y1-kappa B sequence, specifically binds kappa B-related complexes in nuclear extracts from rat brain areas, NG108-15 cells, and the murine T cell clone A.E7. In nuclear extracts from A.E7 and NG108-15 cells, the Y1-kappa B sequence specifically binds an additional complex whose molecular nature remains to be elucidated. Through transient transfection studies, we also demonstrated that the Y1-kappa B sequence acts as an enhancer element, inferring its potential role in regulation of the Y1 receptor gene expression.

Neuroprotection by aspirin and sodium salicylate through blockade of NF-kappaB activation

Aspirin (acetylsalicylic acid) is a commonly prescribed drug with a wide pharmacological spectrum. At concentrations compatible with amounts in plasma during chronic anti-inflammatory therapy, acetylsalicylic acid and its metabolite sodium salicylate were found to be protective against neurotoxicity elicited by the excitatory amino acid glutamate in rat primary neuronal cultures and hippocampal slices. The site of action of the drugs appeared to be downstream of glutamate receptors and to involve specific inhibition of glutamate-mediated induction of nuclear factor kappa B. These results may contribute to the emerging theme of anti-inflammatory drugs and neurodegeneration.