Redefining left bundle branch block from high-density electroanatomical mapping.

BACKGROUND: The existing ECG criteria for diagnosing left bundle branch block (LBBB) are insufficient to distinguish between true and false blocks accurately. METHODS: We hypothesized that the notch width of the QRS complex in the lateral leads (I, avL, V5, V6) on the LBBB-like ECG could further confirm the diagnosis of true complete left bundle branch block (t-LBBB). We conducted high-density, three-dimensional electroanatomical mapping in the cardiac chambers of 37 patients scheduled to undergo CRT. These patients' preoperative electrocardiograms met the ACC/AHA/HRS guidelines for the diagnosis of complete LBBB. If the left bundle branch potential could be mapped from the base of the heart to the apex on the left ventricular septum, it was defined as a false complete left bundle branch block (f-LBBB). Otherwise, it was categorized as a t-LBBB. We conducted a comparative analysis between the two groups, considering the clinical characteristics, real-time correspondence between the spread of ventricular electrical excitation and the QRS wave, QRS notch width of the lateral leads (I, avL, V5, V6), and the notch width/left ventricular end-diastolic diameter (Nw/LVd) ratio. We performed the ROC correlation analysis of Nw/LVd and t-LBBB to determine the sensitivity and specificity for diagnostic authenticity. RESULTS: Twenty-five patients were included in the t-LBBB group, while 12 patients were assigned to the f-LBBB group. Within the t-LBBB group, the first peak of the QRS notch correlated with the depolarization of the right ventricle and septum, the trough corresponded to the depolarization of the left ventricle across the left ventricle, and the second peak aligned with the depolarization of the left ventricular free wall. In contrast, within the f-LBBB group, the first peak coincided with the depolarization of the right ventricle and a majority of the left ventricle, the second peak occurred due to the depolarization of the latest, locally-activated myocardium in the left ventricle, and the trough was a result of delayed activation of the left ventricle that did not align with the usual peak timing. The QRS notch width (45.2 ± 12.3 ms vs. 52.5 ± 9.2 ms, P < 0.05) and the Nw/LVd ratio (0.65 ± 0.19 ms/mm vs. 0.81 ± 0.17 ms/mm, P < 0.05) were compared between the two groups. After conducting the ROC correlation analysis, a sensitivity of 56% and a specificity of 91.7% for diagnosing t-LBBB using Nw/LVd were obtained. CONCLUSION: By utilizing the current diagnostic criteria for LBBB, an increased Nw/LVd value can enhance the effectiveness of diagnosing LBBB.

Three-dimensional electroanatomical mapping guidelines for the selection of pacing site to achieve cardiac resynchronization therapy.

Objectives: We aimed to evaluate the feasibility of left ventricular electroanatomical mapping to choose between left bundle branch area pacing (LBBAP) or coronary venous pacing (CVP). Background: There are several ways to achieve left ventricular activation in cardiac resynchronization therapy (CRT): LBBAP and CVP are two possible methods of delivering CRT. However, the criteria for choosing the best approach remains unknown. Methods: A total of 71 patients with heart failure, reduced ejection fraction, and left bundle branch block (LBBB) were recruited, of which 38 patients underwent the three-dimensional electroanatomical mapping of the left ventricle to accurately assess whether the left bundle branch was blocked and the block level, while the remaining 33 patients were not mapped. Patients with true LBBB achieved CRT by LBBAP, while patients with pseudo-LBBB achieved CRT by CVP. After a mean follow-up of 6 months and 1 year, the QRS duration and transthoracic echocardiography, including mechanical synchrony indices, were evaluated. Results: Twenty-five patients with true LBBB received LBBAP, while 13 without true LBBB received CVP. Seventeen patients received LBBAP, and 16 patients received CVP without mapping. Paced QRS duration after the implantation of LBBAP and CVP was significantly narrower in the mapping subgroup compared to the non-mapping subgroup. A significant increase in post-implantation left ventricular ejection fraction was observed in patients with LBBAP or CVP, and the mapping subgroup were better than the non-mapping subgroup. After a 12-month follow-up, atrioventricular, intraventricular, and biventricular synchronization were significantly improved in the mapping subgroup compared to non-mapping groups in both LBBAP and CVP. Conclusion: In our study, three-dimensional electroanatomical mapping was used to choose LBBAP or CVP for heart failure patients, which proved feasible, with better cardiac resynchronization in the long-term follow-up. Therefore, three-dimensional electroanatomical mapping before CRT appears to be a reliable method for heart failure patients with LBBB who are indicated for CRT.

[Performance and Mechanism Study of Visible Light-driven C3N4/BiOBr Composite Photocatalyst].

Efficient visible light-driven C3N4/BiOBr composite photocatalysts were prepared via a facile hydrothermal method and characterized by X-ray diffraction, Fourier transform infrared, scanning electron microscopy, UV-Vis diffuse reflectance spectra and photoluminescence spectra for the phase composition and optical property. Taking rhodamine B (RhB) as the target pollutant, the photocatalytic activity and stability of photocatalysts were studied under visible light irradiation. Furthermore, the mechanism in the process of photocatalytic degradation was discussed by electron spin resonance spectroscopy analysis and the trapping experiment of generated radicals. The results indicated that C3N4/BiOBr composite photocatalysts had excellent crystallization performance. Composited by C3N4, BiOBr exhibited considerably higher photocatalytic activity by reducing the rate of electron-hole recombination. Among prepared composites with various C3N4 contents, 15% C3N4/BiOBr exhibited the best efficiency for the degradation of RhB. After irradiation for 18 minutes, the degradation rate of RhB was 100%, which was 1.5 times higher than that using pure BiOBr. The results also suggested that holes and ·O2- were the main reactive species in the photocatalytic process for the RhB degradation, and holes played the leading role.

Possible novel roles of poly(rC)-binding protein 1 in SH-SY5Y neurocytes: an analysis using a dynamic Bayesian network.

OBJECTIVE: Poly(rC)-binding protein 1 (PCBP1) belongs to the heterogeneous nuclear ribonucleoprotein family and participates in transcriptional and translational regulation. Previous work has identified transcripts targeted by both knockdown and overexpression of PCBP1 in SH-SY5Y neuroblastoma cells using a microarray or ProteomeLab protein fractionation 2-dimensions (PF-2D) and quadrupole time-of-flight mass spectrometer. The present study aimed to further determine whether these altered transcripts from major pathways (such as Wnt signaling, TGF-ß signaling, cell cycling, and apoptosis) and two other genes, H2AFX and H2BFS (screened by PF-2D), have spatial relationships. METHODS: The genes were studied by qRT-PCR, and dynamic Bayesian network analysis was used to rebuild the coordination network of these transcripts. RESULTS: PCBP1 controlled the expression or activity of the seven transcripts. Moreover, PCBP1 indirectly regulated MAP2K2, FOS, FST, TP53 and WNT7B through H2AFX or regulated these genes through SAT. In contrast, TP53 and WNT7B are regulated by other genes. CONCLUSION: The seven transcripts and PCBP1 are closely associated in a spatial interaction network.

A proteomic investigation of B lymphocytes in an autistic family: a pilot study of exposure to natural rubber latex (NRL) may lead to autism.

Autism is a multi-factorial neurodevelopmental disorder. We have investigated the molecular mechanism involved in a Chinese family with autism by a proteomic approach. Antibody chips containing 500 spots of human protein antibodies were used to screen for differentially expressed proteins in the peripheral B lymphocytes between autistic and non-autistic siblings in this family. Four proteins relevant to immuno-pathway, including IKKα that was up-regulated and Tyk2, EIF4G1 and PRKCI that were down-regulated, were identified differentially expressed in autistic versus non-autistic siblings. Western blot analysis and reverse transcription quantitative polymerase chain reaction validated the differential expression of these four proteins. Based on the function of these differentially expressed proteins, relevant studies on immunoglobulin E (IgE) level, nuclear factor kappa B signaling activation and cell cycle were conducted in both autistic and non-autistic children of this family. Considering the fact that the family members were in close contact with natural rubber latex (NRL) and that IgE-mediated cross-reactions could be triggered by Hevea brasiliensis (Hev-b) proteins in NRL, we hypothesize that immune reactions triggered by close contact with NRL might influence the functions of B lymphocytes by altering expression of certain proteins identified in our experiments thus contributing to the occurrence of autism.

Identification of differentially expressed transcripts and translatants targeted by knock-down of endogenous PCBP1.

PCBP1 is a member of the hnRNP family and participates in the regulation of transcription and translation. Previously, we identified transcripts targeted by overexpression of exogenous PCBP1. To further determine if these altered transcripts may also be targeted by a lack of PCBP1, we depleted endogenous PCBP1 in human SH-SY5Y cells. We identified 941 transcripts with the Affymetrix and 1362 with the Agilent expression platforms. There were 375 transcripts identified by both platforms, including 328 down-regulated and 47 up-regulated. The identified transcripts could be grouped into neuronal, cell signaling, metabolic, developmental, and differentiation categories, with pathway involvement in Wnt signaling, TGF beta signaling, translation factors and nuclear receptors. A proteomic profiling study with a two-dimensional chromatographic platform showed global translational changes over a range of isoelectric points (pI)=4.84-8.42. This study identifies the transcripts affected by knock-down of endogenous PCBP1 and compares them to the transcripts affected by overexpression of PCBP1.

Identification of novel partner proteins of PCBP1.

OBJECTIVE: PCBP1 is a family member of heterogeneous nuclear ribonucleoproteins (hnRNPs) that belong to RNA-binding proteins and bear three KH domains. The protein plays a pivotal role in post-transcriptional regulation for RNA metabolism and RNA function in gene expression. We hypothesized and were going to identify that the regulatory function of PCBP1 is performed through different complexes of proteins that include PCBP1. METHODS: To test our hypothesis, approaches of protein walking with a yeast two-hybrid system (Y2H), pulling down in yeasts, co-immunoprecipitation and immunofluorescent microscopy assay were employed in this study. The PCBP1 was used as the initial "walker" to search for its interaction partner(s). RESULTS: Candidate proteins including MYL6, PECAM1, CSH1, RAB7, p57KIP2, ACTG1, RBMS1 and PSG4-like were identified with selection mediums and preceding methods. CONCLUSION: With these candidate protein molecules, some protein complexes associating with PCBP1 are proposed, which may help in a better understanding of physiological functions of PCBP1 and proved evidence that PCBP1 is involved in variant biological pathways.

[The same mutation Glu208Lys in the GJB1 gene was detected in 2 families with X-linked Charcot-Marie-Tooth disease].

Mutation of GJB1 gene was investigated in two families with X-linked Charcot-Marie-Tooth disease. Genomic DNA from venous blood samples was prepared. The coding sequence of the GJB1 gene was amplified from genomic DNA. PCR products were analyzed by single strand conformational polymorphism (SSCP) method. The PCR product having an abnormal pattern was sequenced to detect the mutation. It was found that the samples of all patients and one little girl with normal phenotype showed an abnormal SSCP band, but not detected in the other unaffected members in the first large family. In the second small family, an abnormal SSCP band was found in all the patients, but not detected in the unaffected member. The result of DNA sequencing demonstrated that both families had a same mutation of 622G-->A, which resulted in a substitution of Glu208Lys. This mutation has not been reported previously in China.

[Effect of wolfberry fruit and epimedium on DNA synthesis of the aging-youth 2BS fusion cells].

OBJECTIVE: To study the effect of water extracts of Wolfberry fruit (WB) and Epimedium (EM) on DNA synthesis of the aging-youth 2BS fusion cells. METHODS: Human embryonic lung diploid fibroblasts 2BS national standard strain, were used as an aging model. Cell denucleation and cell fusion techniques were applied to observe the effect of WB and EM on DNA synthesis of 2BS fusion cells. RESULTS: In the 0.025 (V/V) WB or EM water extract containing media, 2BS cells could be continuously cultured for 61.0 +/- 2.9 passages and 56.0 +/- 2.6 passages respectively, while in the control group it was only 49.0 +/- 2.6 passages (P < 0.01). After treatment with WB and EM separately for 2 hrs, the aging 2BS cells were denucleated and fused with young 2BS cells. The [3H]TdR incorporation percentage in these treated cells was significantly higher than that in the untreated control cells (P < 0.01). CONCLUSION: Both WB and EM can accelerate the DNA synthesis rate of the aging youth 2BS fusion cells and prolong the life span of 2BS cells.