C and G are frequently mutated into T and A in coding regions of human genes.

Nucleotide mutations in human genes have long been a hot subject for study because some of them may lead to severe human diseases. Understanding the general mutational process and evolutionary trend of human genes could help answer such questions as why certain diseases occur and what challenges we face in protecting human health. In this study, we conducted statistics on 89,895 single-nucleotide variations identified in coding regions of 18,339 human genes. The results show that C and G are frequently mutated into T and A in human genes. C/G (C or G)-to-T/A mutations lead to reduction of hydrogen bonds in double-stranded DNA because C-G and T-A base pairs are maintained by three and two hydrogen bonds respectively. C-to-T and G-to-A mutations occur predominantly in human genes because they not only reduce hydrogen bonds but also belong to transition mutation. Reduction of hydrogen bonds could reduce energy consumption not only in separating double strands of mutated DNA for transcription and replication but also in disrupting stem-loop structure of mutated mRNA for translation. It is thus considered that to reduce hydrogen bonds (and thus to reduce energy consumption in gene expression) is one of the driving forces for nucleotide mutation. Moreover, codon mutation is positively correlated to its content, suggesting that most mutations are not targeted on changing any specific codons (amino acids) but are merely for reducing hydrogen bonds. Our study provides an example of utilizing single-nucleotide variation data to infer evolutionary trend of human genes, which can be referenced to conduct similar studies in other organisms.

Identification of genes associated with the silk gland size using multi-omics in silkworm (Bombyx mori).

Silk gland size in silkworms (Bombyx mori) affects silk output. However, the molecular mechanisms by which genes regulate silk gland size remain unclear. In this study, silk glands from three pure silkworm strains (A798, A306 and XH) with different silk gland weight phenotypes were compared using transcriptomics and proteomics to identify differentially expressed genes (DEGs) and proteins (DEPs). When comparing A798 to A306 and A798 to XH, 830 and 469 DEGs were up-regulated, respectively. These genes were related to the gene ontology terms, metabolic process, transport activity and biosynthesis process. In addition, 372 and 302 up-regulated differentially expressed proteins were detected in A798 to A306 and A798 to XH, respectively, related to the gene ontology terms, ribosome and protein export, ribosome and polypeptide biosynthesis processes. Moreover, combined transcriptomics, proteomics and weighted correlation network analyses showed that five genes (BGIBMGA002524, BGIBMGA002629, BGIBMGA005659, BGIBMGA005711 and BGIBMGA010889) were significantly associated with the silk gland weight. Reverse Transcription-quantitative real-time Polymerase Chain Reaction (RT-qPCR) and Enzyme linked immunosorbent assay (ELISA) were used to verify the mRNA and protein expression of five genes in the silk glands and tissues of 18 silkworm strains. The results showed that four genes have higher expression levels in heavier silk glands. These genes are associated with glycogen metabolism, fatty acid synthesis and branched chain amino acid metabolism, thus potentially promoting growth and silk protein synthesis. These findings provide valuable insights into the molecular mechanisms underlying the relationship between silk gland weight and silk yield in silkworms.

Characterization of the UDP-glycosyltransferase UGT33D1 in silkworm Bombyx mori.

Uridine diphosphate (UDP)-glycosyltransferases (UGTs) are important metabolizing enzymes functioning by adding a sugar moiety to a small lipophilic substrate molecule and play critical roles in drug/toxin metabolism for all realms of life. In this study, the silkworm Bombyx mori UGT33D1 gene was characterized in detail. UGT33D1 was found localized in the endoplasmic reticulum (ER) compartment just like other animal UGTs and was mainly expressed in the silkworm midgut. We first reported that UGT33D1 was important to BmNPV infection, as silencing UGT33D1 inhibited the BmNPV infection in silkworm BmN cells, while overexpressing the gene promoted viral infection. The molecular pathways regulated by UGT33D1 were analysed via transcriptome sequencing upon UGT33D1 knockdown, highlighting the important role of the gene in maintaining a balanced oxidoreductive state of the organism. In addition, proteins that physically interact with UGT33D1 were identified through immunoprecipitation and mass spectrometry analysis, which includes tubulin, elongation factor, certain ribosomal proteins, histone proteins and zinc finger proteins that had been previously reported for human UGT-interacting proteins. This study provided preliminary but important functional information on UGT33D1 and is hoped to trigger deeper investigations into silkworm UGTs and their functional mechanisms.

Bombyx mori RPL13 participates in UV-induced DNA damage repair of B. mori nucleopolyhedrovirus through interaction with Bm65.

Ribosomal protein L13 (RPL13) is highly conserved in evolution. At present, the properties and functions of RPL13 have not been characterised in insects. In this study, Bombyx mori RPL13 (BmRPL13) was first found to be specifically recruited to the sites of ultraviolet (UV)-induced DNA damage and contributed to UV damage repair. Escherichia coli expressing BmRPL13 showed better resistance to UV radiation. After knocking down the expression of BmRPL13 in BmN cells, the repair speed of UV-damaged DNA slowed down. The further results showed that BmRPL13 interacted with B. mori nucleopolyhedrovirus (BmNPV) ORF65 (Bm65) protein to locate at the UV-induced DNA damage sites of BmNPV and helped repair UV-damaged viral DNA.

Prognostic implications of premature ventricular contractions and non-sustained ventricular tachycardia in light-chain cardiac amyloidosis.

AIMS: Premature ventricular contractions (PVC) and non-sustained ventricular tachycardia (NSVT) are commonly observed in light chain cardiac amyloidosis (AL-CA), but their association with prognosis is still unclear. We aimed to evaluate the prognostic value of PVCs and NSVT in patients with moderate-to-advanced AL-CA. METHODS AND RESULTS: We retrospectively included patients with AL-CA at modified 2004 Mayo stages II-IIIb between February 2014 and December 2020. Twenty-four-hour Holter recordings were assessed on admission. The outcomes included (i) new onset of adverse ventricular arrhythmia (VA) or sudden cardiac death (SCD) and (ii) cardiac death during follow-up. Of the 143 patients studied (60.41 ± 11.06 years, male 64.34%), 132 (92.31%) had presence of PVC, and 50 (34.97%) had NSVT on Holter. Twelve (8.4%) patients died in hospital and 131 patients were followed up (median 24.4 months), among whom 71 patients had cardiac death, and 15 underwent adverse VA/SCD. NSVT [hazard ratio (HR): 13.57, 95% confidence interval (CI): 3.06-60.18, P < 0.001], log-transformed PVC counts (HR: 1.46, 95%CI: 1.15-1.86, P = 0.002) and PVC burden (HR: 1.43 95%CI:1.14-1.80, P = 0.002) were predictive of new onset of adverse VA/SCD. The highest tertile of PVC counts (HR: 2.33, 95%CI: 1.27-4.28, P = 0.006) and PVC burden (HR: 2.58, 95%CI: 1.42-4.69, P = 0.002), rather than NSVT (HR: 1.16, 95%CI: 0.67-1.98, P = 0.603), was associated with cardiac death. Higher PVC counts/burden provided incremental value on modified 2004 Mayo stage in predicting cardiac death, with C index increasing from 0.681 to 0.712 and 0.717, respectively (P values <0.05). CONCLUSION: PVC count, burden, and NSVT significantly correlated with adverse VA/SCD during follow-up in patients with AL-CA. Higher PVC counts/burdens added incremental value for predicting cardiac death.

Anatomical variation of femoral vessels and ultrasound-guided femoral vein puncture for catheter ablation of arrhythmias.

OBJECTIVE: This study aims to investigate the anatomical variations in femoral vasculature and evaluate the clinical value of ultrasound-guided femoral vein puncture in catheter ablation procedures. METHODS: In this retrospective analysis conducted from January 2023 to March 2023, we examined data from patients who underwent catheter ablation with ultrasound-guided femoral venipuncture. We evaluated the anatomy of the femoral vasculature at both high and low inguinal levels. Based on the relationship between the femoral vein and artery, we classified the anatomy into four types: Type I (vein parallel to artery without overlap), Type II (vein medial to artery with lumen overlap ≤50%), Type III (vein posterior to artery with lumen overlap > 50%), and Type IV (vein lateral to artery). Additionally, we assessed procedure-related vascular complications that required interventions or prolonged hospital stays. RESULTS: A total of 254 patients were included in this study. At the upper inguinal level, most cases (92.5%) exhibited Type II, followed by Type I (6.5%), while Type III (0.6%) and IV (0.4%) were less common. At the lower inguinal level, Type II accounted for 70.7%, there was a significantly higher proportion of Type III (23.4%) and Type IV (5.9%). The overall complication rate was 0.4%, no pseudoaneurysm or hematoma was observed in our study. CONCLUSION: Our study revealed significant anatomical variations in the relationship between the femoral vein and femoral artery. Ultrasound-guided femoral venipuncture significantly reduced vascular complication rate, making it a valuable tool for guiding puncture procedures.

The zona pellucida protein piopio regulates the metamorphosis and reproduction in Tribolium castaneum.

The zona pellucida domain protein piopio (Pio) was only reported to mediate the adhesion of the apical epithelial surface and the overlying apical extracellular matrix in Drosophila melanogaster, but the developmental roles of Pio were poorly understood in insects. To address this issue, we comprehensively analyzed the function of Pio in Tribolium castaneum. Phylogenetic analysis indicated that pio exhibited one-to-one orthologous relationship among insects. T. castaneum pio had a 1236-bp ORF and contained eight exons. During development pio was abundantly expressed from larva to adult and lowly expressed at the late stage of embryo and adult, while it had more transcripts in the head, epidermis, and gut but fewer in the fat body of late-stage larvae. Knockdown of pio inhibited the pupation, eclosion, and reproduction of T. castaneum. The expression of vitellogenin 1 (Vg1), Vg2, and Vg receptor (VgR) largely decreased in pio-silenced female adults. Silencing pio increased the 20-hydroxyecdysone titer by upregulating phm and spo expression but decreased the juvenile hormone (JH) titer through downregulating JHAMT3 and promoting JHE, JHEH-r4, and JHDK transcription. These results suggested that Pio might regulate the metamorphosis and reproduction via modulating the ecdysone and JH metabolism in T. castaneum. This study found the novel roles of pio in insect metamorphosis and reproduction, and provided the new insights for analyzing other zona pellucida proteins functions in insects.

Cloning of suppressor of cytokine signaling 7 from silkworm (Bombyx mori) and its response to the infection of Bombyx mori nucleopolyhedrovirus.

Suppressors of cytokine signaling (SOCS) play important roles in the regulation of growth, development, and immunity of eukaryotic organisms. SOCS7 is an important member of the SOCS family, but its physiological and pathological functions remain largely unknown in invertebrates including insects. Here, we first report the cloning of a SOCS7 gene from a domesticated silkworm (Bombyx mori), named BmSOCS7. We have characterized BmSOCS7 expression profiles in silkworm varieties susceptible or resistant to the infection of Bombyx mori nucleopolyhedrovirus (BmNPV) using the real-time fluorescence quantitative PCR. BmSOCS7 expresses highly in embryogenesis and lowly in metamorphosis in resistant silkworms but does in opposite contrast in susceptible silkworms. Its expression is at very low level in the fat body of resistant silkworms but is relatively high in the fat body of susceptible ones. BmNPV inoculation induces a transient downregulation and then a general upregulation of BmSOCS7 expression in BmN cells, while it induces a general downregulation in silkworm midgut, fat body and hemolymph with more pronounced effect in resistant silkworms than susceptible ones and more prominent in the fat body and hemolymph than the midgut. Together, our work reveals that downregulation of BmSOCS7 expression may be an important strategy for silkworm anti-BmNPV immune response, and BmSOCS7 may mainly function in the fat body and hemolymph rather than the midgut to participate in BmNPV infection process.

Comparison of Three Detection Methods for Seoul Virus Causing Hemorrhagic Fever with Renal Syndrome.

BACKGROUND: Seoul virus (SEOV) is a significant causative pathogen of hemorrhagic fever with renal syndrome (HFRS). Accurate discrimination of SEOV infection from other viral or bacterial infections holds vital clinical importance. METHODS: Our study utilized quantitative real-time PCR (qRT-PCR), metagenomic next-generation sequencing (mNGS), and immunological assays to identify the pathogen causing HFRS. RESULTS: For the case, mNGS identified SEOV and suspected host or environmental microorganisms at 5 days from symptom onset. qRT-PCR detected SEOV between 5 to 8 days from symptom onset. Anti-hantavirus IgM antibodies reached positive criteria at 7 days and IgG antibodies at 9 days from symptom onset. CONCLUSIONS: qRT-PCR, mNGS, and immunological assays each have merits and drawbacks. Optimal selection depends on laboratory conditions and clinical requirements.

Transcriptome analysis indicates the mechanisms of BmNPV resistance in Bombyx mori midgut.

Bombyx mori nucleopolyhedrovirus (BmNPV) caused serious economic losses in sericulture. Analyzing the molecular mechanism of silkworms (B. mori) resistance to BmNPV is of great significance for the prevention and control of silkworm virus diseases and the biological control of agricultural lepidopteran pests. In order to clarify the defense mechanisms of silkworms against BmNPV, we constructed a near isogenic line BC8 with high resistance to BmNPV through the highly BmNPV-resistant strain NB and the highly BmNPV-susceptible strain 306. In this study, RNA-Seq technique was used to analyze the transcriptome level differences in the midgut of BC8 and 306 following BmNPV infection. A total of 1350 DEGs were identified. Clustering analysis showed that these genes could be divided into 8 clusters with different expression patterns. Functional annotations based on GO and KEGG analysis indicated that they were involved in various metabolism pathways. Finally, 32 BmNPV defense responsive genes were screened. They were involved in metabolism, reactive oxygen species (ROS), signal transduction and immune response, and insect hormones. The further verification shows that HSP70 should participate in resistance responses of anti-BmNPV. These findings have paved the way in further functional characterization of candidate genes and subsequently can be used in breeding of BmNPV resistance dominant silkworms.

Comprehensive transcriptome sequencing of silkworm Midguts: Uncovering extensive isoform diversity and alternative splicing in BmNPV-Sensitive and BmNPV-resistant strains.

The silkworm, Bombyx mori, stands out as one of the few economically valuable insects within the realm of model organisms. However, Bombyx mori nucleopolyhedrovirus (BmNPV) poses a significant threat, decreasing the quality and quantity of silkworm cocoons. Over the past few decades, a multitude of researchers has delved into the mechanisms that underlie silkworm resistance to BmNPV, employing diverse methodologies and approaching the problem from various angles. Despite this extensive research, the role of alternative splicing (AS) in the silkworm's response to BmNPV infection has been largely unexplored. This study leveraged both third-generation (Oxford Nanopore Technologies) and second-generation (Illumina) high-throughput sequencing technologies to meticulously identify and analyze AS patterns in the context of BmNPV response, utilizing two distinct silkworm strains-the susceptible strain 306 and the resistant strain NB. Consequently, we identified five crucial genes (Dsclp, LOC692903, LOC101743583, LOC101742498, LOC101743809) that are linked to the response to BmNPV infection through AS and differential expression. Additionally, a thorough comparative analysis was conducted on their diverse transcriptomic expression profiles, including alternative polyadenylation, simple sequence repeats, and transcription factors.

Metabolomics captures the differential metabolites in the replication pathway of snakehead vesiculovirus regulated by glutamine.

Snakehead vesiculovirus (SHVV) is a negative-sense single-stranded RNA virus that infects snakehead fish. This virus leads to illness and mortality, causing significant economic losses in the snakehead aquaculture industry. The replication and spread of SHVV in cells, which requires glutamine as a nitrogen source, is accompanied by alterations in intracellular metabolites. However, the metabolic mechanisms underlying the inhibition of viral replication by glutamine deficiency are poorly understood. This study utilized liquid chromatography-mass spectrometry to measure the differential metabolites between the channel catfish Parasilurus asotus ovary cell line infected with SHVV under glutamine-containing and glutamine-deprived conditions. Results showed that the absence of glutamine regulated 4 distinct metabolic pathways and influenced 9 differential metabolites. The differential metabolites PS(16:0/16:0), 5,10-methylene-THF, and PS(18:0/18:1(9Z)) were involved in amino acid metabolism. In the nuclear metabolism functional pathway, differential metabolites of guanosine were observed. In the carbohydrate metabolism pathway, differential metabolites of UDP-d-galacturonate were detected. In the signal transduction pathway, differential metabolites of SM(d18:1/20:0), SM(d18:1/22:1(13Z)), SM(d18:1/24:1(15 Z)), and sphinganine were found. Among them, PS(18:0/18:1(9Z)), PS(16:0/16:0), and UDP-d-galacturonate were involved in the synthesis of phosphatidylserine and glycoprotein. The compound 5,10-methylene-THF provided raw materials for virus replication, and guanosine and sphingosine are related to virus virulence. The differential metabolites may collectively participate in the replication, packaging, and proliferation of SHVV under glutamine deficiency. This study provides new insights and potential metabolic targets for combating SHVV infection in aquaculture through metabolomics approaches.

Transcriptome-wide identification of development related genes and pathways in Tribolium castaneum.

The growth and development in Tribolium castaneum were poorly understood at the transcriptome level. Currently, we identified 15,756, 9941 and 10,080 differentially expressed transcripts between late eggs VS early larvae, late larvae VS early pupae, and late pupae VS early adults of T. castaneum by RNA-seq, which was confirmed by qRT-PCR analysis on nine genes expression. Functional enrichment analysis indicated that DNA replication, cell cycle and insect hormone biosynthesis significantly enriched differentially expressed genes. The transcription of DNA replication and cell cycle genes decreased after hatching but increased after pupation. The juvenile hormone (JH) and ecdysteroid biosynthesis genes decreased after hatching, and the JH degradation genes were stimulated after pupation and eclosion while the ecdysteroid degradation gene CYP18A1 decreased after pupation. Silencing CYP18A1 elevated the titer of ecdysteroids and caused developmental arrest at the late larval stage. This study promotes the understanding of insect growth and development.

The Mechanisms of Silkworm Resistance to the Baculovirus and Antiviral Breeding.

Silkworm (Bombyx mori) is not only an economic insect but also a model organism for life science research. Bombyx mori nucleopolyhedrovirus (BmNPV) disease is a major infectious disease in the world's sericulture industry. The cocoon loss caused by this disease accounts for more than 60% of the total loss caused by all silkworm diseases. To date, there has been no effective solution for preventing and treating this disease. The most effective measure is to breed disease-resistant varieties. The quickest way to breed disease-resistant varieties is to apply genetic modification. However, this requires that we obtain disease resistance genes and know the mechanism of disease resistance. Since the discovery of disease-resistant resources in 1989, scholars in the sericulture industry around the world have been inspired to search for resistance genes. In the past two decades, with the help of multi-omics technologies, screening of resistance genes, gene localization, protein modification, virus-host interactions, etc., researchers have found some candidate genes that have been proposed to function at the cellular or individual level. Several disease-resistant varieties have been obtained and used in production through hybrid breeding, RNA interference, and genetic modification. This article summarizes and reviews the discovery of and research advances related to silkworm resistance to BmNPV. It is anticipated that the review will inspire scientific researchers to continue searching for disease resistance genes, clarify the molecular mechanism of silkworm disease resistance, and promote disease-resistant silkworm breeding.

BmNPV Orf 65 (Bm65) Is Identified as an Endonuclease Directly Facilitating UV-Induced DNA Damage Repair.

Baculoviruses have been used as biopesticides for the control of Lepidoptera larvae. However, solar UV radiation reduces the activity of baculovirus. In this study, an UV endonuclease, Bm65, was found encoded in the genome of Bombyx mori nuclear polyhedrosis virus (BmNPV). Bm65 (the ortholog of AcMNPV orf79) was guided by a key nuclear localization signal to enter the nucleus and accumulated at UV-induced DNA damage sites. Subsequent results further showed that Bm65-mediated DNA damage repair was not the only UV damage repair pathway of BmNPV. BmNPV also used host DNA repair proteins to repair UV-induced DNA damage. In summary, these results revealed that Bm65 was very important in UV-induced DNA damage repair of BmNPV, and BmNPV repaired UV-damaged DNA through a variety of ways. IMPORTANCE Baculovirus biopesticides are environmentally friendly insecticides and specifically infect invertebrates. UV radiation from the sunlight greatly reduces the activity of baculovirus biopesticides. However, the molecular mechanisms of most baculoviruses to repair UV-induced DNA damage remain unclear. Nucleotide excision repair (NER) is a major DNA repair pathway that removes UV-induced DNA lesions. At present, there are few reports about the nucleotide excision repair pathway in viruses. Here, we showed for the first time that the baculovirus Bm65 endonuclease actually cleaved UV-damaged DNA. Meanwhile, we found that BmNPV used both viral-encoded enzymes and host DNA damage repair proteins to reverse UV-induced DNA damage. These results will provide a reference for the research of UV damage repair of other viruses.

Clinical use conditions of lead deployment and simulated lead fracture rate in left bundle branch area pacing.

INTRODUCTION: Left bundle branch area pacing (LBBAP) is achieved by advancing the lead tip deep in the septum. Most LBBAP implants are performed using the Medtronic SelectSecure™ MRI SecureScan™ Model 3830 featuring a unique 4 Fr fixed helix lumenless design. Details of lead use conditions and long-term reliability have not been reported. This study was designed to quantify the mechanical use conditions for the 3830 lead during and after LBBAP implant, and to evaluate reliability using bench testing and simulation. METHODS: Fifty bradycardia patients with implantation of the 3830 lead for LBBAP were enrolled. Use conditions of lead deployment at implantation were collected and computed tomography (CT) scans were performed at 3-month follow-up. Curvature amplitude along the pacing lead was determined with CT images. Fatigue bending was performed using accelerated testing in a more severe environment than routine clinical use conditions. Conductor fracture rate in a simulated patient population was estimated based on clinical use conditions and fatigue test results. RESULTS: The number of attempts to place the 3830 lead for LBBAP was 2.1 ± 1.3 (range: 1-7) with 13 ± 6 lead rotations at the final attempt. Extreme implant conditions were simulated in bench testing with 5 applications of 20 turns followed by up to 400 million bending cycles. Reliability modeling predicted a 10-year fracture rate of 0.02%. CONCLUSIONS: LBBAP implants require more lead rotations than standard pacing implants and result in unique lead bending. Application of simulated LBBAP use conditions to the 3830 lead in an accelerated in-vitro model does not produce excess conductor fractures. IMAGE-LBBP Study ID of ClinicalTrial.GOV: NCT04119323.

Eukaryotic initiation factor 6 modulates the metamorphosis and reproduction of Tribolium castaneum.

Eukaryotic initiation factor 6 (eIF6) is necessary for ribosome biogenesis and translation, but eIF6 has been poorly elucidated in insects. Phylogenetic analysis demonstrated that eIF6 originated from one ancestral gene among animals and exhibited specific duplication in Tribolium, yielding three homologues in Tribolium castaneum, eIF6, eIF6-like 1 (eIF6l1), and eIF6-like 2 (eIF6l2). It was found that eIF6 was highly expressed in the embryonic and early adult stages, eIF6l1 had peak expression at the adult stage, and eIF6l2 showed peak expression in late adults of T. castaneum. Tissue-specific analyses in late-stage larvae demonstrated that eIF6 was abundantly expressed in all tissues, while eIF6l1 and eIF6l2 had the highest expression in the gut and the lowest expression in the head of T. castaneum. Knockdown of eIF6 caused precocious pupation and eclosion, impaired ovary and testis development and completely repressed egg production. The expression levels of vitellogenin 1 (Vg1), Vg2 and Vg receptor (VgR) significantly decreased in ds-eIF6 females 5 days post-adult emergence. Silencing eIF6 activated ecdysteroid biosynthesis and juvenile hormone degradation but reduced the activity of insulin signalling in T. castaneum, which might mediate its roles in metamorphosis, reproduction and gene expression regulation. However, silence of eIF6l1 or eIF6l2 had no effects on metamorphosis and reproduction in T. castaneum. This study provides comprehensive information for eIF6 evolution and function in the insect.

Quantitative analysis reveals influencing factors to facilitate successful anodal-ring capture in left bundle branch pacing.

AIMS: Left bundle branch pacing (LBBP) maintains left ventricular synchrony but induces right ventricular conduction delay (RVCD). Although anodal-ring capture (ARC) during bipolar LBBP improves RVCD, it is not achieved in all patients receiving LBBP. This study aimed to analyze the factors influencing ARC implementation. METHODS AND RESULTS: Patients receiving LBBP with intraoperative ARC testing were enrolled. Electrocardiographic parameters were measured, including stimulus-to-QRS duration (stim-QRSd), stimulus-to-left/right ventricular activation time (stim-LVAT/RVAT), and V6-V1 interpeak interval. The distribution of lead-tip sites was described as the corrected longitudinal and lateral distance (longit-/lat-dist). Relative angles of the LBBP lead were measured. Echocardiography in short-axis view was used to measure the intraseptal lead length. Intergroup comparisons, correlation analysis, and stepwise logistic regression were performed. In total, 105 patients were included, among which 65 (62%) patients achieved ARC at a pacing output ≤ 5.0 V/0.5 ms (average 3.1 V/0.5 ms). Anodal-ring capture further shortened the stim-QRSd by 13.1 ± 7.5 ms. Better unipolar-ring (cathodal) threshold and R-wave sensing in LBBP-ARC group indicated the critical role of ring-septum contact in ARC. Longer corrected longit-dist and shorter corrected lat-dist of lead-tip sites were positively correlated with higher success likelihood of ARC, likely due to the greater relative angle in which the lead enters the septum and consequently the longer intraseptal lead length and better ring-septum contact. CONCLUSION: This study elucidated the factors affecting the success likelihood of LBBP-ARC. These findings improve the understanding of LBBP-ARC, providing references for future research and clinical practice.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy.

AIMS: Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP. METHODS AND RESULTS: Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05). CONCLUSION: Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

Research progress on nucleic acid detection and genome editing of CRISPR/Cas12 system.

PURPOSE: This work characterizes the applications of CRISPR/Cas12 system, including nucleic acid detection, animal, plant and microbial genome editing. METHODS: The literature on CRISPR/Cas12 system was collected and reviewed. RESULTS: CRISPR/Cas system is an acquired immune system derived from bacteria and archaea, which has become the most popular technology around the world because of its outstanding contribution in genome editing. Type V CRISPR/Cas systems are distinguished by a single RNA-guided RuvC nuclease domain with single effector molecule. Cas12a, the first reported type V CRISPR/Cas system, targets double-stranded DNA (dsDNA) adjacent to PAM sequences and trans-cleaves single-stranded DNA (ssDNA). We present the applications of CRISPR/Cas12 system for nucleic acid detection and genome editing in animals, plants and microorganisms. Furthermore, this review also summarizes the applications of other Cas12 proteins, such as Cas12b, Cas12c, Cas12d, and so on, which further widen the application prospects of CRISPR/Cas12 system. CONCLUSIONS: Knowledge of the applications of CRISPR/Cas12 system is necessary for improving the understanding of the functional diversity of CRISPR/Cas12 system and also provides significant references for further research and utilization of CRISPR/Cas12 in other new fields.