[Feasibility and safety of new simplified left bundle branch area pacing via nine-partition method].

Objective: To investigate the efficacy and safety of left bundle branch area pacing (LBBaP) with the new simplified approach (nine-partition method). Methods: A total of 118 patients with clinical indications and received pacemaker implantation from December 1, 2018 to December 31, 2019 in Beijing Anzhen Hospital were enrolled. LBBaP was performed with the nine-partition method (in the right anterior oblique 30° position, the ventriculogram was divided into nine partitions and the initial implant sites were located in the lower base 1/3 partitions). In X-ray image, the 3830 lead is located in the left bundle branch area, the unipolar pacing QRS wave is in the form of right bundle branch block, and the peak time from stimulation to left ventricular activation<90 ms is defined as successful operation. The clinical characters, such as the methods of venipuncture, electrode parameters, operation duration, fluoroscopy duration, the peak time from stimulation to left ventricular, pacemaker types, surgical success rate, complications, and immediate postoperative ECG parameters were collected. The patients were followed up after the operation, and the electrode parameters and postoperative complications were recorded. Results: This study is a retrospective study. There were 62 (52.5%) male patients in this cohort, the average age was (65.9±13.4) years old,and there were 49(41.5%) sick sinus syndrome, 6(5.1%) abnormal sinus node and atrioventricular node simultaneously, 63(53.4%) atrioventricular block, 26(22.0%) atrial fibrillation, 20(16.9%) cardiomyopathy; the baseline duration of QRS was (109.21±39.03) ms. Successful LBBaP was achieved in 109 patients with"nine-partition method"and the success rate was 92.4%; 104 patients (95.5%) were axillary vein puncture, 5 (4.6%) were subclavian vein puncture; the operation duration was (80.3±23.0) min, the fluoroscopy duration was (12.29±5.13) min; the QRS duration after LBBaP was (116.36±18.11) ms. The threshold of the left bundle branch (LBB) lead was (0.92±0.63) V, the R wave amplitude was (10.60±5.04) mV and the impedance was (798.71±194.90) Ω. In 1 V pacing, the peak time from stimulation to left ventricular activation was (67.91±12.15) ms, and in 5 V pacing was (67.52±12.45) ms; 1 case (0.9%) with a single-chamber pacemaker implanted, 106 cases (97.3%) with dual-chamber pacemaker and 2 cases (1.8%) with three-chamber pacemakers. There were no hematomas, pneumothorax, hemothorax, electrode dislocation, infection, and capsular hemorrhage and other serious surgery-related complications during the operation. A total of 97 patients (89.0%) were followed up for (6.21±2.90) months. The electrode parameters of all patients were stable and no complications observed. Conclusions: The LBBaP with nine-partition method is a simple, safe and effective physiological pacing approach. However, its long-term effect still needs to be further verified.

[The role of DFO in Al (mal) (3)-induced ferroptosis in PC12 cells].

Objective: To investigate the mechanism of Al (mal) (3)-induced ferroptosis in rat adrenal pheochromocytoma cells (PC12), to explore the effect of deferoxamine (DFO) . Methods: Taken PC12 cells growing at logarithmic phase and divided into 6 groups: control group, 200 µmol/L Al (mal) (3) group, 0.5% DMSO group, 200 µmol/L DFO group, Al (mal) (3)+DMSO group, Al (mal) (3)+DFO group. DMSO and DFO were added to the DMSO group and the Al (mal) (3)+DMSO group, the DFO group and the Al (mal) (3)+DFO group for 2 h, respectively, Al (mal) (3) was then added to the Al (mal) (3) group, Al (mal) (3)+DMSO group, and the Al (mal) (3)+DFO group to a final concentration of 200 µmol/L. The cell viability was detected by CCK8, the morphology and ROS levels of PC12 cells was observed by inverted microscope, the cell proliferation toxicity and intracellular iron ion content were detected by colorimetry, the GSH content and GSH-PX activity were detected by biochemical method. Results: Al (mal) (3) exposure significantly inhibited the growth of PC12 cells and destroyed the cell morphological structure, resulting in increased LDH activity and intracellular iron ion content in PC12 cells, decreased GSH content and GSH-PX activity, increased ROS levels; the combined treatment of Al (mal) (3)+DFO can significantly improve the cell viability of PC12 cells, improved cell morphology, decreased cell LDH activity and intracellular iron ion content (P>0.05), increased GSH content and GSH-PX activity, decreased ROS levels. Conclusion: Al (mal) (3) can induce ferroptosis in PC12 cells, DFO may inhibit ferroptosis by reducing intracellular iron levels and reducing oxidative damage.

Seasonal changes in blood pressure in chronic kidney disease patients.

BACKGROUND: Seasonal variation in blood pressure (BP) in different populations has been described. However, no study has concentrated on the change of blood pressure in chronic kidney disease (CKD) patients, a large and growing population worldwide. Furthermore, the role of volume status in seasonal blood pressure variations remains controversial. METHODS: 109 CKD patients in a single center were followed between January 1, 2007 and December 31, 2007. Systolic and diastolic blood pressure, level of serum creatinine and body weight were measured in these patients and studied along with climatology data obtained from Beijing Weather Bureau. RESULTS: Blood pressure varied throughout the year, following a cyclic pattern. It increased from the autumn months toward winter, and decreased toward the spring and warmer months. The seasonal variation of blood pressure in CKD patients appeared not to correlate with CKD stage and similar seasonal variations were observed. Blood pressure values in the cohort of CKD patients were inversely correlated with outdoor temperatures (SBP: r = -0.882, p < 0.001; DBP: r = -0.860, p < 0.001). Furthermore, there was no significant difference in body weight between summer and winter (p > 0.05) in this group of CKD patients. CONCLUSIONS: Our results suggest that the blood pressure of CKD patients varied with the seasonal variation. The seasonal variation of blood pressure in CKD patients seemed to have no correlation with stage of CKD or change of body weight but was inversely associated with outdoor temperatures. These results suggested that volume status might not be a key mechanism causing seasonal variation in blood pressure.

Dewetting-controlled binding of ligands to hydrophobic pockets.

We report on a combined atomistic molecular dynamics simulation and implicit solvent analysis of a generic hydrophobic pocket-ligand (host-guest) system. The approaching ligand induces complex wetting-dewetting transitions in the weakly solvated pocket. The transitions lead to bimodal solvent fluctuations which govern magnitude and range of the pocket-ligand attraction. A recently developed implicit water model, based on the minimization of a geometric functional, captures the sensitive aqueous interface response to the concave-convex pocket-ligand configuration semiquantitatively.

Does loss of residual renal function lead to malnutrition in peritoneal dialysis patients?

OBJECTIVES: It is usually believed that loss of residual renal function is associated with anorexia and the development of malnutrition. We conducted a retrospective study in our center to evaluate the effect of declining residual renal function on patients' nutritional status. METHODS: All incident uremic patients (n = 46) who began peritoneal dialysis from January 1, 2003 June 1, 2003 in our center were closely followed for 1 year with focus on maintaining strict volume control with time on dialysis. Patient's residual renal function (RRF) was assessed by the average renal urea and creatinine clearances. Those patients who had more than 50% decrease in GFR were selected for the present analysis. Serum albumin (ALB), dietary protein intake (DPI) and subjective global assessment (SGA) were closely followed. RESULTS: There were 16 patients (9 males and 7 females) included in the present analysis, among whom 31.3% were diabetics. Patients' GFR declined significantly (RRF were 4.32 +/- 2.69, 2.99 +/- 2.21 and 1.24 +/- 0.99 ml/min for Months 1, 6 and 12, respectively, p < 0.05), along with a significant decline in urine volume (985.62 +/- 543.29, 698.13 +/- 463.59 and 425.63 +/- 320.52 ml/d for Months 1, 6 and 12, respectively, p < 0.01). Although weekly peritoneal Kt/V did not increase significantly, peritoneal ultrafiltration increased significantly during this period (428.75 +/- 408.96, 534.38 +/- 296.39, 844.38 +/- 440.35 ml for Months 1, 6 and 12, respectively, p < 0.05). Serum ALB increased significantly (32.34 +/- 5.07, 34.74 +/- 4.89 and 36.21 +/- 3.98 g/l for Months 1, 6 and 12, respectively, p < 0.01). DPI also increased significantly. The prevalence of malnutrition (by SGA) decreased from 62.5% at the start of dialysis to 18.8% at the end of this study (p < 0.05). CONCLUSIONS: Our study suggests that rapid decline of residual renal function in PD patients does not necessarily lead to decreased dietary protein intake and deteriorated nutritional status. Focus on incremental peritoneal fluid removal along with the decline in residual renal function and, thus, maintaining volume control may be one of the critical reasons for the success.

Spinal epidural haemangioma associated with extensive gastrointestinal haemangiomas. A case report.

SUMMARY: A case of spinal epidural cavernous haemangioma associated with gastrointestinal haemangiomas is discussed. The patient was a young Chinese female presenting with chronic lower back pain. She had a history of extensive gastric and small bowel haemangiomas. Lumbar spine MRI showed a heterogeneously enhancing epidural mass infiltrating the paravertebral muscles. Open biopsy confirmed an epidural cavernous haemangioma. To our knowledge, an association between spinal epidural cavernous haemangiomas and gastrointestinal haemangiomas has not been reported.

Large first hyperpolarizabilities in push-pull polyenes by tuning of the bond length alternation and aromaticity.

Conjugated organic compounds with 3-phenyl-5-isoxazolone or N,N'-diethylthiobarbituric acid acceptors have large first molecular hyperpolarizabilities (beta) in comparison with compounds with 4-nitrophenyl acceptors. For example, julolidinyl-(CH=CH)(3)-CH=N,N'- diethylthiobarbituric acid, which has 12 atoms between the donor and acceptor, has a beta(0) of 911 x 10(-30) electrostatic units, whereas (CH(3))(2)NC(6)H(4),-(CH=CH)(4)-C(6)H(4)NO(2), with 16 atoms between its donor and acceptor, has a beta(0) of 133 x 10(-30) electrostatic units. The design strategies demonstrated here have resulted in chromophores that when incorporated into poled-polymer electrooptic modulators exhibited significant enhancements in electrooptic coefficients relative to polymers containing the commonly used dye Disperse Red-1. Poled polymer devices based on these or related chromophores may ultimately lead to high-speed electrooptic switching elements with low drive-power requirements, suitable for telecommunications applications.

Approaches for optimizing the first electronic hyperpolarizability of conjugated organic molecules.

A two-state, four-orbital, independent electron analysis of the first optical molecular hyperpolarizability, beta, leads to the prediction that |beta| maximizes at a combination of donor and acceptor strengths for a given conjugated bridge. Molecular design strategies that focus on the energetic manipulations of the bridge states are proposed for the optimization of beta. The limitations of molecular classes based on common bridge structures are highlighted and more promising candidates are described. Experimental results supporting the validity of this approach are presented.

Velocity of sound and equations of state for methanol and ethanol in a diamond-anvil cell.

The adaptability of laser-induced phonon spectroscopy to the determination of acoustic velocity and the equation of state in the diamond-anvil high-pressure cell is demonstrated. The technique provides a robust method for measurements at high pressure in both solids and liquids so that important problems in high-pressure elasticity and the earth sciences are now tractable. The velocity of sound and the density of methanol at 25 degrees C have been measured up to a pressure of 6.8 gigapascals. These results imply a higher density (by approximately 5 percent) for liquid methanol above 2.5 gigapascals than that given in existing compilations. The adiabatic bulk modulus increases by a factor of 50 at a maximum compression of 1.8. The thermodynamic Grüneisen parameters of methanol and ethanol both increase with increasing pressure, in contrast to the behavior of most solids.