Micro-Three-Coil Sensor with Dual Excitation Signals Use Asymmetric Magnetic Fields to Distinguish between Non-Ferrous Metals.

Intelligent operation and maintenance technology for vessels can ensure the safety of the entire system, especially for the development of intelligent and unmanned marine technology. The material properties of metal abrasive particles in oil could demonstrate the wear areas of the marine mechanical system because different components consist of different materials. However, most sensors can only roughly separate metallic contaminants into ferromagnetic and non-ferromagnetic particles but cannot differentiate them in greater detail. A micro-three-coil sensor is designed in this paper; the device applies different excitation signals to two excitation coils to differentiate materials, based on the different effects of different material particles in the asymmetric magnetic field. Therefore, a particle's material can be judged by the shape of the induction electromotive force output signal from the induction coil, while the particle size can be judged by the amplitude of the signal. Experimental results show that the material differentiation of four different types of particles can be achieved, namely, of aluminum, iron, 304 stainless steel, and carbon steel. This newly designed sensor provides a new research prospect for the realization of an inductive detection method to distinguish non-ferrous metals and a reference for the subsequent detection of metal contaminants in oil and other liquids.

Characterization of the RACK1 gene of Aips cerana cerana and its role in adverse environmental stresses.

Receptors for Activated C Kinase 1 (RACK1s) are a kind of multifunction scaffold protein that plays an important role in cell signal transductions and animal development. However, the function of RACK1 in the Chinese honeybee Apis cerana cerana is little known. Here, we isolated and identified a RACK1 gene from Apis cerana cerana, named AccRACK1. By bioinformatic analysis, we revealed a high nucleic acid homology between AccRACK1 and RACK1 of Apis cerana. RT-qPCR analyses demonstrated AccRACK1 was mostly expressed in 3rd instar larvae, darked-eyed pupae and adults (one and thirty days post-emergence), suggesting it might participate in the development of A. cerana cerana. Moreover, the expression of AccRACK1 was highest in the thorax, followed by the venom gland. Compared to the blank control group, AccRACK1 was induced by 24 and 44 °C, HgCl2 and pesticides (paraquat, pyridaben and methomyl) but inhibited by 14 °C, H2O2, UV light and cyhalothrin. Additionally, 0.05, 0.1, 1, 5 and 10 mg/ml PPN (juvenile hormone analogue pyriproxyfen) could promote the expression of AccRACK1, with 1 mg/ml showing the highest upregulation, suggesting it was regulated by hormones. Further study found that after knockdown of AccRACK1 by RNAi, the expression of the eukaryotic initiation factor 6 of A. cerana cerana (AcceIF6), an initiation factor regulating the initiation of translation, was inhibited, indicating AccRACK1 might affect cellular responses by translation. These findings, taken together, suggest AccRACK1 is involved in the development and responses to abiotic stresses of A. cerana cerana, and therefore, it may be of critical importance to the survival of A. cerana cerana.

Initial experience of a novel method for electrical isolation of the superior vena cava using cryoballoon in patients with atrial fibrillation.

BACKGROUND: Damage to the sinus node (SN) has been described as a potential complication of superior vena cava (SVC) isolation. There have been reports of permanent SN injury requiring pacemaker implantation during isolation of the SVC. HYPOTHESIS: It is safe and effective to isolate SVC with the second-generation 28-mm cryoballoon by using a novel method. METHODS: Forty-three patients (including six redo cases) with SVC-related atrial fibrillation (AF) from a consecutive series of 650 patients who underwent cryoballoon ablation were included. After pulmonary vein isolation was achieved, if the SVC trigger was identified, the SVC was electrically isolated using the cryoballoon. First, the cryoballoon was inflated in the right atrium (RA) and advanced towards the SVC-RA junction. After total occlusion was confirmed by dye injection with total retention of contrast in the SVC, the SVC-RA junction was determined. Next, the cryoballoon was deflated, advanced into SVC, then reinflated, and pulled back gently. The equatorial band of the cryoballoon was then set slightly (4.32 ± 0.71 mm) above the SVC-RA junction for isolation of the SVC. RESULTS: Real-time SVC potential was observed in all patients during ablation. The mean time to isolation was 24.5 ± 10.7 s. The SVC was successfully isolated in all patients. The mean number of freeze cycles was 2.5 ± 1.4 per patient, and the mean ablation time was 99.8 ± 22.7 s. A transient phrenic nerve (PN) injury occurred in one patient (2.33%). There were no SN injuries. Freedom from AF rates at 6 and 12 months was 97.7% and 93.0%, respectively. CONCLUSIONS: This novel method for SVC isolation using the cryoballoon is safe and feasible when the SVC driver during AF is determined and could avoid SN injury. PN function should still be carefully monitored during an SVC isolation procedure.

Investigation of the Effect of Debris Position on the Detection Stability of a Magnetic Plug Sensor Based on Alternating Current Bridge.

Magnetic plug-type abrasive particle sensors have a wide range of applications in oil detection, but there is little literature on the effect of abrasive particle position on detection accuracy. In this paper, an alternating current (AC) bridge-type abrasive particle detection sensor is designed, in which the sensing module utilizes permanent magnets to attract iron particles, and the induction coil is specially designed to detect the magnetic field fluctuation caused by iron particles. A corresponding model was also designed to evaluate the sensor's sensitivity at different locations. In this paper, the magnetic field distribution of the sensor was first analyzed using finite element analysis software to obtain the magnetic field strength at different positions. Then, the response sensitivity of the sensor to particles and the effect of different positions on the detection results are explored through experiments. The simulation and the experimental results show substantial signal difference signal at different sensor positions. The method outlined in this article can determine the optimal sensing range for subsequent magnetic plug-type abrasive particle detection sensors and subsequently improve their reliability.

A novel mutation in human EMD gene and mitochondrial dysfunction in emerin knockdown cardiomyocytes.

Emerin is an inner nuclear envelope protein encoded by the EMD gene, mutations in which cause Emery-Dreifuss muscular dystrophy type 1 (EDMD1). Cardiac involvement has become a major threat to patients with EDMD1; however, the cardiovascular phenotype spectrums of emerinopathy and the mechanisms by which emerin regulates cardiac pathophysiology remain unclear. Here, we identified a novel nonsense mutation (c.C57G, p.Y19X) in the EMD gene in a Han Chinese family through high-throughput sequencing. Two family members were found to have EDMD1 with muscle weakness and cardiac arrhythmia. Mechanistically, we first discovered that knockdown of emerin in HL-1 or H9C2 cardiomyocytes lead to impaired mitochondrial oxidative phosphorylation capacity with downregulation of electron transport chain complex I and IV and upregulation of complex III and V. Moreover, loss of emerin in HL-1 cells resulted in collapsed mitochondrial membrane potential, altered mitochondrial networks and downregulated multiple factors in RNA and protein level, such as PGC1α, DRP1, MFF, MFN2, which are involved in regulation of mitochondrial biogenesis, fission and fusion. Our findings suggest that targeting mitochondrial bioenergetics might be an effective strategy against cardiac disorders caused by EMD mutations.

Prognostic Implications of Left Atrial Spontaneous Echo Contrast with Catheter Ablation of Nonvalvular Atrial Fibrillation Patients with Left Atrial Dilation.

Background: Left atrial spontaneous echo contrast (LASEC) can be detected by transesophageal echocardiography (TEE) before the catheter ablation of atrial fibrillation (AF), especially in patients with left atrial (LA) dilation. Whether LASEC has prognostic value in predicting the procedure outcomes in patients with an enlarged atrium is unknown. The prognostic implications of LASEC with the catheter ablation of AF patients with LA dilation will be evaluated in this study. Methods: AF patients scheduled to undergo catheter ablation in Ruijin Hospital, Shanghai, China, between January 2018 and June 2020 were screened for this prospective study. All patients underwent TEE before the procedure. Patients with a left atrial diameter (LAD; 45 mm ≤ LAD < 50 mm) and left atrial volume (LAV ≥ 120 mL) were enrolled in this study. The endpoint was AF/atrial tachycardia (AT) recurrence-free survival following a 3-month blanking period after the catheter ablation. All patients were followed up for 18 months. Results: This study included 123 AF patients, who were divided into the LASEC (n = 73) and no LASEC (n = 50) groups. Baseline patient characteristics were similar in the two groups. At the end of 18 months of follow-up, AF/AT recurrence-free survival was achieved in 33 (45.2%) and 34 (68.0%) patients in the LASEC and no LASEC groups, respectively (p = 0.013). In survival analysis, the LASEC group was also associated with a poor outcome of catheter ablation (log-rank test, p = 0.011; Cox regression, p = 0.015, HR = 2.058, 95%CI = 1.151−3.679). Meanwhile, during the follow-up AF/AT recurrence was observed in 30 (57.7%) and 15 (71.4%) cases in the mild and severe SEC groups, respectively. Ischemic stroke occurred in two patients in the LASEC group. Conclusions: LASEC could be a predictor of the recurrence of AF/AT after catheter ablation in AF patients with LA dilation. The higher the degree of LASEC, the worse the prognosis.

Identification and Verification of Feature Biomarkers Associated With Immune Cells in Dilated Cardiomyopathy by Bioinformatics Analysis.

Objective: To explore immune-related feature genes in patients with dilated cardiomyopathy (DCM). Methods: Expression profiles from three datasets (GSE1145, GSE21610 and GSE21819) of human cardiac tissues of DCM and healthy controls were downloaded from the GEO database. After data preprocessing, differentially expressed genes (DEGs) were identified by the 'limma' package in R software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were then performed to identify biological functions of the DEGs. The compositional patterns of stromal and immune cells were estimated using xCell. Hub genes and functional modules were identified based on protein-protein interaction (PPI) network analysis by STRING webtool and Cytoscape application. Correlation analysis was performed between immune cell subtypes and hub genes. Hub genes with |correlation coefficient| > 0.5 and p value <0.05 were selected as feature biomarkers. A logistic regression model was constructed based on the selected biomarkers and validated in datasets GSE5406 and GSE57338. Results: A total of 1,005 DEGs were identified. Functional enrichment analyses indicated that extracellular matrix remodeling and immune and inflammation disorder played important roles in the pathogenesis of DCM. Immune cells, including CD8+ T-cells, macrophages M1 and Th1 cells, were proved to be significantly changed in DCM patients by immune cell infiltration analysis. In the PPI network analysis, STAT3, IL6, CCL2, PIK3R1, ESR1, CCL5, IL17A, TLR2, BUB1B and MYC were identified as hub genes, among which CCL2, CCL5 and TLR2 were further screened as feature biomarkers by using hub genes and immune cells correlation analysis. A diagnosis model was successfully constructed by using the three biomarkers with area under the curve (AUC) scores 0.981, 0.867 and 0.946 in merged dataset, GSE5406 and GSE57338, respectively. Conclusion: The present study identified three immune-related genes as diagnostic biomarkers for DCM, providing a novel perspective of immune and inflammatory response for the exploration of DCM molecular mechanisms.

Analysis of the Effect of Velocity on the Eddy Current Effect of Metal Particles of Different Materials in Inductive Bridges.

A method for analyzing the influence of velocity changes on metal signals of different materials in oil detection technology is proposed. The flow rate of metal contaminants in the oil will have a certain impact on the sensitivity of the output particle signal in terms of electromagnetic fields and circuits. The detection velocity is not only related to the sensitivity of the output particle signal, but also to the adaptability of high-speed and high-throughput in oil online monitoring. In this paper, based on a high-sensitivity inductive bridge, the eddy current effect of velocity in a time-harmonic magnetic field is theoretically analyzed and experimentally verified, the phenomenon of particle signal variation with velocity for different materials is analyzed and discussed, and finally the effect of velocity on the output signal of the processing circuit is also elaborated and experimentally verified. Experiments show that under the influence of the time-harmonic magnetic field, the increase of the velocity enhances the detection sensitivity of non-ferromagnetic metal particles and weakens the detection sensitivity of non-ferromagnetic particles. Under the influence of the processing circuit, different velocities will produce different signal gains, which will affect the stability of the signal at different velocities.

Plasma protein profiling analysis in patients with atrial fibrillation before and after three different ablation techniques.

Background: There are controversies on the pathophysiological alteration in patients with atrial fibrillation (AF) undergoing pulmonary vein isolation using different energy sources. Objectives: We evaluated the changes in plasma proteins in acute phase post-ablation in patients receiving cryoballoon ablation, radiofrequency balloon ablation, or radiofrequency ablation. Methods: Blood samples from eight healthy controls and 24 patients with AF were taken on the day of admission, day 1, and day 2 post-ablation and analyzed by the Olink proximity extension assay. Proteins were identified and performed with enrichment analysis. Protein-protein interaction network and module analysis were conducted using Cytoscape software. Results: Of 181 proteins, 42 proteins in the cryoballoon group, 46 proteins in the radiofrequency balloon group, and 43 proteins in the radiofrequency group significantly changed after ablation. Most of the proteins altered significantly on the first day after ablation. Altered proteins were mainly involved in cytokine-cytokine receptor interaction. Both balloon-based ablations showed a similar shift toward enhancing cell communication and regulation of signaling while inhibiting neutrophil chemotaxis. However, radiofrequency ablation presented a different trend. Seed proteins, including osteopontin, interleukin-6, interleukin-10, C-C motif ligand 8, and matrix metalloproteinase-1, were identified. More significant proteins associated with hemorrhage and coagulation were selected in balloon-based ablations by machine learning. Conclusion: Plasma protein response after three different ablations in patients with AF mainly occurred on the first day. Radiofrequency balloon ablation shared similar alteration in protein profile as cryoballoon ablation compared with radiofrequency ablation, suggesting that lesion size rather than energy source is the determinant in pathophysiological responses to the ablation.

Differences in D-dimer blood concentration in atrial fibrillation patients with left atrial thrombus or severe left atrial spontaneous echo contrast.

PURPOSE: Severe left atrial spontaneous echo contrast (SLASEC) is considered the prior stage to thrombosis and a high-risk factor for thrombotic events. Studies have suggested an effect of D-dimer blood concentration on exclusion of left atrial thrombus (LAT), but it remains unclear whether D-dimer concentrations differ between atrial fibrillation (AF) patients with SLASEC or LAT. METHODS: Nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2017 and July 2020 were screened for this prospective study. All patients underwent transesophageal echocardiography (TEE) to detect SLASEC or LAT. D-dimer concentrations were measured at the time of TEE. Clinical data including CHA2DS2-VASc score were evaluated. Major complications with thromboembolism in the SLASEC group were followed up at least 6 months after therapy. RESULTS: Among 920 consecutively enrolled nonvalvular AF patients, 30 patients with SEC grade 0, 35 patients with SLASEC, and 22 patients with LAT were included. D-dimer concentration and CHA2DS2-VASc score were significantly lower in the SLASEC group compared with the LAT group (D-dimer, 0.26±0.13 vs. 0.86±0.9 mg/L, P<0.05; CHA2DS2-VASc score, 2.3±0.9 vs. 3.1±1.5, P=0.02). The cut-off value for D-dimer concentration (0.285 mg/L) had sensitivity of 77.3% and specificity of 80.0% for prediction of LAT. D-dimer concentration showed a decreasing trend with a significant difference (0.42±0.22 vs. 0.33±0.18 mg/L, P=0.03) for 9 patients in the LAT group after complete thrombus resolution by anticoagulation treatment. No major or fatal bleeding, ischemic stroke, or systemic thromboembolism events occurred in the SLASEC group during the 6-month follow-up. CONCLUSIONS: This study demonstrated a significantly lower D-dimer concentration and CHA2DS2-VASc score in AF patients with SLASEC than in those with LAT. The D-dimer cut-off value (0.285 mg/L) can be used as an effective reference index to distinguish the pre-thrombotic state of LAT from LAT. D-dimer blood concentration may be a predictor of LAT thrombolysis.

A Novel Impedance Micro-Sensor for Metal Debris Monitoring of Hydraulic Oil.

Hydraulic oil is the key medium for the normal operation of hydraulic machinery, which carries various wear debris. The information reflected by the wear debris can be used to predict the early failure of equipment and achieve predictive maintenance. In order to realize the real-time condition monitoring of hydraulic oil, an impedance debris sensor that can detect inductance and resistance parameters is designed and studied in this paper. The material and size of wear debris can be discriminated based on inductance-resistance detection method. Silicon steel strips and two rectangular channels are designed in the sensor. The silicon steel strips are used to enhance the magnetic field strength, and the double rectangular detection channels can make full use of the magnetic field distribution region, thereby improving the detection sensitivity and throughput of the sensor. The comparison experiment shows that the coils in series are more suitable for the monitoring of wear debris. By comparing and analyzing the direction and the presence or absence of the signal pulses, the debris sensor can detect and distinguish 46 µm iron particles and 110 µm copper particles. This impedance detection method provides a new technical support for the high-precision distinguishing measurement of metal debris. The sensor can not only be used for oil detection in the laboratory, but also can be made into portable oil detection device for machinery health monitoring.

Label-free proteomic analysis of serum exosomes from paroxysmal atrial fibrillation patients.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac heterogeneous rhythm disorder. It represents a major cause of mortality and morbidity, mainly related to embolic events and heart failure. Mechanisms of AF are complex and remain incompletely understood. Recent evidence suggests exosomes are membrane-coated objects released by many cell-types. Their presence in body fluids and the variable surface composition and content render them attractive as a mechanism for potential biomarkers. However, the content of serum exosomes of AF patients has not been fully delineated. METHODS: In this work, the serum exosomes from AF patients and healthy donors were used to compare changes in the exosome protein content. Exosomes were isolated from serum of AF patients and healthy donors and their purity was confirmed by Western blotting assays and transmission electron microscopy (TEM). Label-free LC-MS/MS quantitative proteomic analysis was applied to analyze protein content of serum exosomes. RESULTS: A total of 440 exosomal protein groups were identified, differentially expressed proteins were filtrated with fold change ≥ 2.0 (AF/controls protein abundance ratio ≥ 2 or ≤ 0.5) and p value less than 0.05 (p < 0.05), significantly changed in abundance group contains 39 elevated proteins and 18 reduced proteins, while consistent presence/absence expression profile group contains 40 elevated proteins and 75 reduced proteins. Bioinformatic analysis of differential exosomal proteins confirmed the significant enrichment of components involved in the anticoagulation, complement system and protein folding. Parallel-Reaction Monitoring Relative Quantitative Analysis (PRM) further suggested that AF related to complement system and protein folding. CONCLUSIONS: These results revealed the composition and potential function of AF serum exosomes, thus providing a new perspective on the complement system and protein folding to AF.

Improving the Detection Ability of Inductive Micro-Sensor for Non-Ferromagnetic Wear Debris.

The inductive debris sensor has been studied because of its wide application prospects in mechanical health monitoring. In order to ensure a high-precision detection performance, a comprehensive method to improve the detection sensitivity and detection ability of the inductive sensor for non-ferromagnetic metal debris is proposed. Based on the characteristics of the eddy current inside the metal, the change of the coil impedance caused by the metal debris is increased by enhancing the magnetic field strength and selecting the optimal excitation frequency. The impedance detection method involving inductance and resistance parameters is used to improve the detection limit of non-ferromagnetic metal debris. The experimental results verify that the magnetic field in the detection region can be enhanced by adding a silicon steel strip (paramagnetic material) in the central hole of the coil, thereby greatly improving the detection sensitivity of the inductive sensor, and the concentrated distribution of the magnetic field avoids the double-peak signals generated by a single particle. The characteristics of the signal amplitude of non-ferromagnetic debris with excitation frequency are studied. Higher inductance, resistance amplitudes, and signal-to-noise ratio (SNR) can be obtained by using a high-frequency alternating current. Compared with inductance parameter detection, resistance parameter detection can detect smaller non-ferromagnetic debris. Combining the detection results of the inductance and resistance parameters can effectively improve the sensor's ability to detect non-ferromagnetic debris.

Design and Parameter Research of Time-Harmonic Magnetic Field Sensor Based on PDMS in Microfluidic Technology.

In order to improve the throughput and sensitivity of the inductive metal micro-abrasive particle detection sensor, this paper uses microfluidic detection technology to design a high-throughput abrasive particle detection sensor based on PDMS (Polydimethylsiloxane). Theoretical modeling analyzes the magnetization of metal abrasive particles in the coil's time-harmonic magnetic field, and uses COMSOL simulation to calculate the best performance parameters of the sensor. Through the experiment of the control variable method, the corresponding signal value is obtained and the signal-to-noise ratio (SNR) is calculated. The SNR value and error value are calculated, and the SNR is corrected. The detection limit of the sensor is determined to be 10 µm iron particles and 60 µm copper particles. The optimal design parameters of the 3-D solenoid coil and the frequency characteristics of the sensor are obtained. Finally, through high-throughput experiments and analysis, it was found that there was a reasonable error between the actual throughput and the theoretical throughput. The design ideas suggested in this article can not only improve the sample throughput, but also ensure the detection accuracy. This provides a new idea for the development of an inductive on-line detection method of abrasive particle technology.

Procedural outcomes and learning curve of cardiac arrhythmias catheter ablation using remote magnetic navigation: Experience from a large-scale single-center study.

BACKGROUND: Remote magnetic navigation (RMN)-guided ablation has become an inspiring method of catheter ablation for tachyarrhythmias. HYPOTHESIS: Data from a large-scale single center may provide further insight into the safety of and the learning curve for RMN-guided ablation. METHODS: A total of 1003 catheter ablation procedures using RMN for conditions including supraventricular ventricular tachycardia, atrial tachyarrhythmias, and premature ventricular contraction/ventricular tachycardia (PVC/VT) were retrospectively analyzed from an ablation registry. Procedural outcomes, including procedure time, mapping time, X-ray time, and RF time, were assessed. The complications were classified into two categories: major and minor. A subanalysis was used to illustrate the learning curve of RMN-guided ablation by assessing procedure time and total X-ray time of 502 atrial fibrillation (AF) ablation procedures. RESULTS: Among these procedures, 556 (55.4%) were AF and 290 (28.9%) were PVC/VT. Electrical pulmonary vein isolation was achieved in 99.0% of AF procedures, and acute success reached 90.3% in PVC/VT procedures. The overall complication rate was 0.5%. In the subanalysis of AF procedures, the overall procedure time and X-ray time of procedures were short (125.9 ± 54.6 and 5.3 ± 3.9 minutes, respectively) and proceeded to decrease from the initial 30 procedures to about 300 procedures, where the learning curve reached plateau, demonstrating maximum procedure efficiency. CONCLUSIONS: RMN-guided ablation is safe, as verified by very low overall complication rate and reduced X-ray time. In our study, even the first AF procedures had a relatively low procedure time and total X-ray time, and procedure efficiency improved during the learning curve.

Outcome of non-vitamin K oral anticoagulants in the treatment of left atrial/left atrial appendage thrombus in patients with nonvalvular atrial fibrillation.

BACKGROUND: Data comparing dabigatran with rivaroxaban regarding the resolution of left atrial/left atrial appendage (LA/LAA) thrombus in patients with nonvalvular atrial fibrillation (AF) are scarce. This study aimed to compare the efficacy and safety of dabigatran vs rivaroxaban regarding the resolution of LA/LAA thrombus in patients with nonvalvular AF. METHODS: This retrospective study enrolled nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2014 and January 2019. Altogether, 34 patients with LA/LAA thrombus detected by transesophageal echocardiography (TEE) were enrolled. Among them, 12 patients were treated with dabigatran 150 mg bid and the other 22 with rivaroxaban 20 mg qd. Follow-up TEE was performed within greater than or equal to 3 weeks to less than 6 months of the initial TEE to evaluate the resolution of the LA/LAA thrombus. RESULTS: Baseline patient characteristics were similar in the two groups. Overall, 18 patients (81.8%) in the rivaroxaban group had complete thrombus resolution after 70.3 ± 22.1 treatment days, and 10 patients (83.3%) in the dabigatran group had complete thrombus resolution after 69.3 ± 47.9 treatment days. There was no significant difference between the groups (P = .6). TEE showed that the average length, width, and area of thrombus significantly decreased in both groups after treatment, although there was no significant difference in the amount of change in these parameters between the two groups after treatment (P = .6). Undissolved thrombus in two patients in the rivaroxaban group did dissolve after switching to dabigatran. CONCLUSIONS: The results suggest that both dabigatran and rivaroxaban are potential options for treating LA/LAA thrombus in patients with nonvalvular AF. Dabigatran could be an alternative option for the resolution of LA/LAA thrombus resistant to rivaroxaban.

Bmi-1 high-expressing cells enrich cardiac stem/progenitor cells and respond to heart injury.

Bmi-1 gene is well recognized as an oncogene, but has been recently demonstrated to play a role in the self-renewal of tissue-specific stem cells. By using Bmi-1GFP/+ mice, we investigated the role of Bmi-1 in cardiac stem/progenitor cells and myocardial repair. RT-PCR and flow cytometry analysis indicated that the expression of Bmi-1 was significantly higher in cardiac side population than the main population from CD45- Ter119- CD31- heart cells. More Sca-1+ cardiac stem/progenitor cells were found in Bmi-1 GFPhi subpopulation, and these Bmi-1 GFPhi heart cells showed the potential of differentiation into SMM+ smooth muscle-like cells and TnT+ cardiomyocyte-like cells in vitro. The silencing of Bmi-1 significantly inhibited the proliferation and differentiation of heart cells. Otherwise, myocardial infarction induced a significantly increase (2.7-folds) of Bmi-1 GFPhi population, mainly within the infarction and border zones. These preliminary data suggest that Bmi-1hi heart cells are enriched in cardiac stem/progenitor cells and may play a role in myocardial repair.

Comparison of efficacy and safety of laser balloon and cryoballoon ablation for atrial fibrillation-a meta-analysis.

BACKGROUND: Laser balloon (LB) and cryoballoon (CB) ablation are two balloon-based catheter ablation technologies used for atrial fibrillation (AF) ablation in recent years. However, the efficacy and the safety of LB ablation in comparison to CB ablation remained indeterminate. We sought to compare these two technologies by conducting meta-analysis of previous studies using both the CB and LB ablation systems for AF ablation. METHODS: We searched electronic scientific databases for studies of LB vs. CB ablation in AF patients. The procedural efficacy was assessed by the success of acute pulmonary vein isolation (PVI) and the 12-month recurrence of any atrial arrhythmia, and the safety was evaluated by the risk of procedure-related complications. RESULTS: A total of 595 participants (LB, n = 292 vs. CB, n = 303) from eight studies were included in this meta-analysis. Risk of acute PVI failure (risk ratio, RR 95% confidence interval [95% CI] = 2.55 [0.86-7.56], P = 0.09) and atrial arrhythmia recurrence in 12 months (RR [95% CI] = 0.91 [0.64-1.28], P = 0.59) were comparable between LB vs. CB ablation, and LB ablation tended to be more effective than CB ablation in paroxysmal AF patients (RR [95% CI] = 0.70 [0.47-1.03], P = 0.07). Risk of procedure-related complications was similar while LB ablation showed slightly higher risk without statistic significance (LB 13.9% vs. CB 9.3%, RR [95% CI] = 1.52 [0.88-2.64], P = 0.14). Compared with CB ablation, LB ablation led to longer procedure duration (weighted mean differences WMD [95% CI] =29.7 [15.8-43.7], P < 0.001) while similar fluoroscopy duration was observed between these two ablation devices (WMD [95% CI] = - 1.99[- 6.46-2.47], P = 0.38). CONCLUSIONS: LB ablation has a trend toward higher procedural efficacy compared with CB ablation in paroxysmal AF patients. However, longer procedure duration and a statistically non-significant trend of more procedure-related complications were also observed in patients ablated by LB. Further larger comparative randomized trials are warranted to disclose the impact of LB compared with CB for ablation of AF.

De Novo Human Cardiac Myocytes for Medical Research: Promises and Challenges.

The advent of cellular reprogramming technology has revolutionized biomedical research. De novo human cardiac myocytes can now be obtained from direct reprogramming of somatic cells (such as fibroblasts), from induced pluripotent stem cells (iPSCs, which are reprogrammed from somatic cells), and from human embryonic stem cells (hESCs). Such de novo human cardiac myocytes hold great promise for in vitro disease modeling and drug screening and in vivo cell therapy of heart disease. Here, we review the technique advancements for generating de novo human cardiac myocytes. We also discuss several challenges for the use of such cells in research and regenerative medicine, such as the immature phenotype and heterogeneity of de novo cardiac myocytes obtained with existing protocols. We focus on the recent advancements in addressing such challenges.

Radiation Exposure Decreases the Quantity and Quality of Cardiac Stem Cells in Mice.

Radiation exposure may increase cardiovascular disease risks; however, the precise molecular/cellular mechanisms remain unclear. In the present study, we examined the hypothesis that radiation impairs cardiac stem cells (CSCs), thereby contributing to future cardiovascular disease risks. Adult C57BL/6 mice were exposed to 3 Gy γ-rays, and heart tissues were collected 24 hours later for further experiments. Although c-kit-positive cells were rarely found, radiation exposure significantly induced apoptosis and DNA damage in the cells of the heart. The ex vivo expansion of CSCs from freshly harvested atrial tissues showed a significantly lower production of CSCs in irradiated mice compared with healthy mice. The proliferative activity of CSCs evaluated by Ki-67 expression was not significantly different between the groups. However, compared to the healthy control, CSCs expanded from irradiated mice showed significantly lower telomerase activity, more 53BP1 foci in the nuclei, lower expression of c-kit and higher expression of CD90. Furthermore, CSCs expanded from irradiated mice had significantly poorer potency in the production of insulin-like growth factor-1. Our data suggest that radiation exposure significantly decreases the quantity and quality of CSCs, which may serve as sensitive bio-parameters for predicting future cardiovascular disease risks.