Effectiveness of the systemic immune inflammation index to predict atrial fibrillation recurrence after cryoablation.

Background: We aimed to investigate the predictive role of systemic immune inflammation index (SII) on atrial fibrillation (AF) recurrence following cryoballoon-based AF ablation. Materials & methods: A total of 370 consecutive patients with symptomatic AF who underwent cryoablation were enrolled. The patients were divided into two groups according to recurrence development. Results: During the follow-up period of 25.0 ± 6.7 months, recurrence was observed in 77 patients (20.8%). Receiver operating characteristic analysis demonstrated that using a cutoff level of 532, SII had a sensitivity of 71% and specificity of 68%. In the multivariate Cox model, high SII was a significant predictor of the recurrence. Conclusion: This study showed that higher SII level is an independent predictor of AF recurrence.

The other side of the medallion in heart failure: Reverse metabolic syndrome.

BACKGROUND AND AIMS: Lower levels of cardiovascular risk factors are associated with an increase in mortality in H.F. To explain this paradox, the term reverse metabolic syndrome (RMetS) has recently been proposed. We suggest defining these patients with lower levels of three risk factors can be combined under the heading "RMetS." We aimed to investigate the effect of MetS and RMetS on hemodynamic parameters and prognosis in patients with H.F. and reduced ejection fraction (HFrEF). METHODS AND RESULTS: We included 304 patients who were performed right heart catheterization and followed up for a median of 16 (0-48) months. We first grouped patients according to the presence of MetS or not, then we added the RMetS category and stratified patients into three groups as MetS, RMetS, and metabolic healthy. Compared with not MetS group, Pulmonary arterial pressures and VO2 were higher in MetS group. In the second step, LVEF, CI, VO2I, O2 delivery, and LVSWI were lowest in RMetS, pulmonary artery pressures were higher in MetS group. In multivariate Cox regression analysis, being in RMetS group was associated with 2.4 times and 1.8 times increased risk for composite end point (CEP) and all-cause mortality, respectively. In Kaplan Meier analysis, RMetS had the highest all-cause mortality and CEP. CONCLUSIONS: We determined that RMetS patients had the worst prognosis with unfavorable hemodynamic profile. Hence, a better understanding of the pathophysiology of RMetS may help refine the treatment targets of CV risk factors, may yield new interventions targeting catabolic syndrome.

Subanaesthetic ketamine and altered states of consciousness in humans.

BACKGROUND: Despite its designation as a 'dissociative anaesthetic,' the dissociative and psychoactive effects of ketamine remain incompletely understood. The goal of this study was to characterise the subjective experiences and accompanying EEG changes with subanaesthetic doses of ketamine. METHODS: High-density EEG was recorded in 15 human volunteers before, during, and after subanaesthetic ketamine infusion (0.5 mg kg-1 over 40 min), with self-reported measures of altered states of consciousness obtained after ketamine exposure. Sensor- and source-level EEG changes were analysed with a focus on spectral power and regional changes. RESULTS: Ketamine-induced altered states were characterised predominantly by dissociative experiences such as disembodiment and ego transcendence; sensory disturbances were also common. Ketamine broadly decreased low-frequency power, with mean reductions largest at alpha (8-12 Hz) in parietal (-0.94 dB, P<0.001) and occipital (-1.8 dB, P<0.001) channel clusters. Significant decreases in alpha were identified in the precuneus and temporal-parietal junction. CONCLUSIONS: Ketamine induces altered states of consciousness during periods of reduced alpha power in the precuneus and temporal-parietal junction. Modulation of these temporal-parietal loci are candidate mechanisms of the psychoactive effects of ketamine, given that this region is involved in multisensory integration, body representation, and consciousness.

Comparison of theory and experiment for NAPL dissolution in porous media.

Contamination of groundwater resources by an immiscible organic phase commonly called NAPL (Non Aqueous Phase Liquid) represents a major scientific challenge considering the residence time of such a pollutant. This contamination leads to the formation of NAPL blobs trapped in the soil and impact of this residual saturation cannot be ignored for correct predictions of the contaminant fate. In this paper, we present results of micromodel experiments on the dissolution of pure hydrocarbon phase (toluene). They were conducted for two values of the Péclet number. These experiments provide data for comparison and validation of a two-phase non-equilibrium theoretical model developed by Quintard and Whitaker (1994) using the volume averaging method. The model was directly upscaled from the averaged pore-scale mass balance equations. The effective properties of the macroscopic model were calculated over periodic unit cells designed from images of the experimental flow cell. Comparison of experimental and numerical results shows that the transport model predicts correctly - with no fitting parameters - the main mechanisms of NAPL mass transfer. The study highlights the crucial need of having a fair recovery of pore-scale characteristic lengths to predict the mass transfer coefficient with accuracy.

Penetration into membrane of amino-terminal region of SecA when associated with SecYEG in active complexes.

The general secretory (Sec) system of Escherichia coli translocates both periplasmic and outer membrane proteins through the cytoplasmic membrane. The pathway through the membrane is provided by a highly conserved translocon, which in E. coli comprises two heterotrimeric integral membrane complexes, SecY, SecE, and SecG (SecYEG), and SecD, SecF, and YajC (SecDF/YajC). SecA is an associated ATPase that is essential to the function of the Sec system. SecA plays two roles, it targets precursors to the translocon with the help of SecB and it provides energy via hydrolysis of ATP. SecA exists both free in the cytoplasm and integrally membrane associated. Here we describe details of association of the amino-terminal region of SecA with membrane. We use site-directed spin labelling and electron paramagnetic resonance spectroscopy to show that when SecA is co-assembled into lipids with SecYEG to yield highly active translocons, the N-terminal region of SecA penetrates the membrane and lies at the interface between the polar and the hydrophobic regions, parallel to the plane of the membrane at a depth of approximately 5 Å. When SecA is bound to SecYEG, preassembled into proteoliposomes, or nonspecifically bound to lipids in the absence of SecYEG, the N-terminal region penetrates more deeply (8 Å). Implications of partitioning of the SecA N-terminal region into lipids on the complex between SecB carrying a precursor and SecA are discussed.

Determination of the intracellular concentration of the export chaperone SecB in Escherichia coli.

SecB, a small tetrameric chaperone in Escherichia coli, plays a crucial role during protein export via the general secretory pathway by binding precursor polypeptides in a nonnative conformation and passing them to SecA, the ATPase of the translocon. The dissociation constants for the interactions are known; however to relate studies in vitro to export in a living cell requires knowledge of the concentrations of the proteins in the cell. Presently in the literature there is no report of a rigorous determination of the intracellular concentration of SecB. The values available vary over 60 fold and the details of the techniques used are not given. Here we use quantitative immunoblotting to determine the level of SecB expressed from the chromosome in E.coli grown in two commonly used media. In rich medium SecB was present at 1.6 ± 0.2 µM and in minimal medium at 2.5 ± 0.6 µM. These values allow studies of SecB carried out in vitro to be applied to the situation in the cell as SecB interacts with its binding partners to move precursor polypeptides through the export pathway.

Evaluation of endothelial dysfunction with flow-mediated dilatation after transradial coronary angiography.

Objective Transradial coronary angiography (TRCA) may lead to endothelial dysfunction. Therefore, this study investigated the TRCA-related endothelial dysfunction and its relation to operator experience, the number of punctures and procedure duration. Methods and results A total of 57 patients (42 males and 17 females) who underwent TRCA were included in this single-centre study. Nine months after the procedure, all patients underwent radial artery B-mode ultrasound imaging, and flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) techniques were employed. The non-intervened right radial artery was accepted as control. The percentage change in diameter after FMD was significantly greater in the right radial artery compared to the left radial artery (right 13.6% vs left 10.1%, P = 0.041). The percentage change in diameter after NMD was similar in both right and left radial arteries (right 23.8% vs left 23.4%, P = 0.932). According to the puncture numbers, the percentage change was significantly lower in the intervened artery among patients with more than one puncture (13.3% vs 7.8%, P = 0.005). According to the operator experience, the percentage change in the intervened artery was significantly higher in patients in whom the procedure was performed by experienced operators (13.7% vs 7.6%, P = 0.002). The procedure duration also showed a negative correlation with the percentage change in the intervened artery (r = -0.349, P = 0.008). Conclusions TRCA may lead to endothelial dysfunction represented by FMD. Moreover, higher puncture numbers for sheath insertion, longer procedure durations and less experience in radial interventions may have adverse effects on the endothelial function.

Red cell distribution width as a predictor of left atrial spontaneous echo contrast in echocardiography.

Red cell distribution width (RDW) represents the heterogeneity of red blood cells (anisocytosis). Spontaneous echo contrast (SEC) is thought to be a manifestation of red cell aggregation and it has been linked to the development of thromboemboli. The aim of this study was to evaluate the association between RDW levels and the presence of left atrial SEC (LASEC). One-hundred and 72 patients who underwent transesophageal echocardiography for various indications were enrolled in the study. All patients were categorized into 2 groups according to the presence of LASEC and into 4 groups according to the severity of LASEC. The baseline clinical characteristics, echocardiographic measurements, and laboratory findings, including RDW, were compared between the groups. The RDW (%) level was higher in the LASEC group (14.95 ±â€Š1.32) compared with the non-LASEC group (12.20 ±â€Š1.45; P = 0.0001). When the relationship between RDW and SEC was evaluated according to the increasing grade of SEC, a significant positive correlation was found (r = 0.645, P < 0.0001). In the ROC analysis, an RDW level >13.8% had 70% sensitivity and 89.2% specificity in predicting LASEC (area under the curve = 0.834, P < 0.0001, 95% CI 0.656-0.773). In multivariate analysis, RDW levels >13.8% and the presence of atrial fibrillation were independently associated with LASEC (odds ratio [OR] 1.697; 95% confidence interval [CI] 1.198-2.085; P = 0.001 and OR 1.586; 95% CI 1.195-2.098; P = 0.003, respectively]. Elevated RDW value is associated with the presence and the severity of SEC. RDW may be a useful marker and independent predictor for the presence of SEC.

DNA adsorption onto polyethylenimine-attached poly(p-chloromethylstyrene) beads.

In this study, DNA adsorption properties of polyethylenimine (PEI)-attached poly(p-chloromethylstyrene) (PCMS) beads were investigated. Spherical beads with an average size of 186 microm were obtained by the suspension polymerization of p-chloromethylstyrene conducted in an aqueous dispersion medium. Owing to the reasonably rough character of the bead surface, PCMS beads had a specific surface area of 14.1 m2/g. PEI chains could be covalently attached onto the PCMS beads with equilibrium binding capacities up to 208 mg PEI/g beads, via a direct chemical reaction between the amine and chloromethyl groups. After PEI adsorption with 10% (w/w) initial PEI concentration, free amino content of PEI-attached PCMS beads was determined as 0.91 mequiv./g. PEI-attached PCMS beads were utilized as sorbents in DNA adsorption experiments conducted at +4 degrees C in a phosphate buffer medium of pH 7.4. DNA immobilization capacities up to 290 mg DNA/g beads could be achieved with the tried sorbents. This value was approximately 50-times higher relative to the adsorption capacities of previously examined sorbents.