2.Changing resistance profiles of Haemophilus influenzae and Moraxella catarrhalis isolates in hospitals across China:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Hui FAN ; Chunhong SHAO ; Jia WANG ; Yang YANG ; Fupin HU ; Demei ZHU ; Yunsheng CHEN ; Qing MENG ; Hong ZHANG ; Chun WANG ; Fang DONG ; Wenqi SONG ; Kaizhen WEN ; Yirong ZHANG ; Chuanqing WANG ; Pan FU ; Chao ZHUO ; Danhong SU ; Jiangwei KE ; Shuping ZHOU ; Hua ZHANG ; Fangfang HU ; Mei KANG ; Chao HE ; Hua YU ; Xiangning HUANG ; Yingchun XU ; Xiaojiang ZHANG ; Wenen LIU ; Yanming LI ; Lei ZHU ; Jinhua MENG ; Shifu WANG ; Bin SHAN ; Yan DU ; Wei JIA ; Gang LI ; Jiao FENG ; Ping GONG ; Miao SONG ; Lianhua WEI ; Xin WANG ; Ruizhong WANG ; Hua FANG ; Sufang GUO ; Yanyan WANG ; Dawen GUO ; Jinying ZHAO ; Lixia ZHANG ; Juan MA ; Han SHEN ; Wanqing ZHOU ; Ruyi GUO ; Yan ZHU ; Jinsong WU ; Yuemei LU ; Yuxing NI ; Jingrong SUN ; Xiaobo MA ; Yanqing ZHENG ; Yunsong YU ; Jie LIN ; Ziyong SUN ; Zhongju CHEN ; Zhidong HU ; Jin LI ; Fengbo ZHANG ; Ping JI ; Yunjian HU ; Xiaoman AI ; Jinju DUAN ; Jianbang KANG ; Xuefei HU ; Xuesong XU ; Chao YAN ; Yi LI ; Shanmei WANG ; Hongqin GU ; Yuanhong XU ; Ying HUANG ; Yunzhuo CHU ; Sufei TIAN ; Jihong LI ; Bixia YU ; Cunshan KOU ; Jilu SHEN ; Wenhui HUANG ; Xiuli YANG ; Likang ZHU ; Lin JIANG ; Wen HE ; Chunlei YUE
Chinese Journal of Infection and Chemotherapy 2025;25(1):30-38
Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91%of the total clinical isolates and 4.07%of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89%were isolated from children and 33.11%were isolated from adults.More than 90%of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79%in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06%were isolated from children and 19.94%isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0%.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.
3.Changing distribution and antimicrobial resistance profiles of clinical isolates in children:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Qing MENG ; Lintao ZHOU ; Yunsheng CHEN ; Yang YANG ; Fupin HU ; Demei ZHU ; Chuanqing WANG ; Aimin WANG ; Lei ZHU ; Jinhua MENG ; Hong ZHANG ; Chun WANG ; Fang DONG ; Zhiyong LÜ ; Shuping ZHOU ; Yan ZHOU ; Shifu WANG ; Fangfang HU ; Yingchun XU ; Xiaojiang ZHANG ; Zhaoxia ZHANG ; Ping JI ; Wei JIA ; Gang LI ; Kaizhen WEN ; Yirong ZHANG ; Yan JIN ; Chunhong SHAO ; Yong ZHAO ; Ping GONG ; Chao ZHUO ; Danhong SU ; Bin SHAN ; Yan DU ; Sufang GUO ; Jiao FENG ; Ziyong SUN ; Zhongju CHEN ; Wen'en LIU ; Yanming LI ; Xiaobo MA ; Yanping ZHENG ; Dawen GUO ; Jinying ZHAO ; Ruizhong WANG ; Hua FANG ; Lixia ZHANG ; Juan MA ; Jihong LI ; Zhidong HU ; Jin LI ; Yuxing NI ; Jingyong SUN ; Ruyi GUO ; Yan ZHU ; Yi XIE ; Mei KANG ; Yuanhong XU ; Ying HUANG ; Shanmei WANG ; Yafei CHU ; Hua YU ; Xiangning HUANG ; Lianhua WEI ; Fengmei ZOU ; Han SHEN ; Wanqing ZHOU ; Yunzhuo CHU ; Sufei TIAN ; Shunhong XUE ; Hongqin GU ; Xuesong XU ; Chao YAN ; Bixia YU ; Jinju DUAN ; Jianbang KANG ; Jiangshan LIU ; Xuefei HU ; Yunsong YU ; Jie LIN ; Yunjian HU ; Xiaoman AI ; Chunlei YUE ; Jinsong WU ; Yuemei LU
Chinese Journal of Infection and Chemotherapy 2025;25(1):48-58
Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1%of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9%)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5%)was lower than that in inpatient children(31.5%).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1%)than in inpatient children(59.4%).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14%,11.7%,47.8%in outpatients,but 24.2%,20.6%,and 52.8%in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.
4.Surveillance of antimicrobial resistance in clinical isolates of Escherichia coli:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Shanmei WANG ; Bing MA ; Yi LI ; Yang YANG ; Fupin HU ; Demei ZHU ; Yingchun XU ; Xiaojiang ZHANG ; Zhaoxia ZHANG ; Ping JI ; Yi XIE ; Mei KANG ; Chuanqing WANG ; Aimin WANG ; Yuanhong XU ; Ying HUANG ; Ziyong SUN ; Zhongju CHEN ; Yuxing NI ; Jingyong SUN ; Yunzhuo CHU ; Sufei TIAN ; Zhidong HU ; Jin LI ; Yunsong YU ; Jie LIN ; Bin SHAN ; Yan DU ; Sufang GUO ; Lianhua WEI ; Fengmei ZOU ; Hong ZHANG ; Chun WANG ; Yunjian HU ; Xiaoman AI ; Chao ZHUO ; Danhong SU ; Dawen GUO ; Jinying ZHAO ; Hua YU ; Xiangning HUANG ; Wen'en LIU ; Yanming LI ; Yan JIN ; Chunhong SHAO ; Xuesong XU ; Chao YAN ; Lixia ZHANG ; Juan MA ; Shuping ZHOU ; Yan ZHOU ; Lei ZHU ; Jinhua MENG ; Fang DONG ; Zhiyong LÜ ; Fangfang HU ; Han SHEN ; Wanqing ZHOU ; Wei JIA ; Gang LI ; Jinsong WU ; Yuemei LU ; Jihong LI ; Jinju DUAN ; Jianbang KANG ; Xiaobo MA ; Yanping ZHENG ; Ruyi GUO ; Yan ZHU ; Yunsheng CHEN ; Qing MENG ; Shifu WANG ; Xuefei HU ; Jilu SHEN ; Wenhui HUANG ; Ruizhong WANG ; Hua FANG ; Bixia YU ; Yong ZHAO ; Ping GONG ; Kaizhen WEN ; Yirong ZHANG ; Jiangshan LIU ; Longfeng LIAO ; Hongqin GU ; Lin JIANG ; Wen HE ; Shunhong XUE ; Jiao FENG ; Chunlei YUE
Chinese Journal of Infection and Chemotherapy 2025;25(1):39-47
Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)%.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0%vs 29.5%).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7%vs 7.8%,0.8%vs 0.1%,both P<0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)%with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9%and 1.8%,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1%).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10%.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P<0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.
5.Correlation of psychological resilience with family function in adolescents
Hengjing WAN ; Lei ZHANG ; Jinhua GAO ; Weibo ZHANG
Chinese Journal of General Practitioners 2025;24(8):985-991
Objective:To investigate the correlation of psychological resilience with family functioning in adolescents.Methods:This study was a cross-sectional study. A total of 1 300 students in the pre-junior to senior grades of three middle schools with medical-educational integration project in Shanghai Minhang District were selected by stratified cluster random sampling from November 2023 to April 2024. Psychological resilience levels and family functioning were assessed using the Resilience Scale for Children and Adolescents (RSCA) and the Family Assessment Device (FAD) among adolescents, respectively. The relationship between psychological resilience levels and family function, and the related influencing factors were examined by Pearson correlation analysis and multiple linear regression analysis.Results:A total of 1 217 valid questionnaires were obtained with an effective rate of 93.6%. There were 600 boys and 617 girls, with an mean age of (14.04±2.19) years. The average score of RSCA for was (87.07±15.96) points. Univariate analysis showed that genders, ethnicities, family structures, parents′ marital status, main caregivers, parenting styles, and having negative life events were significantly associated with psychological resilience levels of adolescents (all P<0.05). Multiple linear regression showed that problem-solving ( β=6.902, P<0.001) and total family function ( β=16.764, P<0.001) were positively correlated with adolescents′ psychological resilience, while emotional response ( β=-3.869, P=0.001), emotional involvement ( β=-4.948, P=0.001), and behavioral control ( β=-6.801, P=0.002) were negatively correlated with adolescents′ psychological resilience. The final model explained 31.7% of the influencing factors of psychological resilience in adolescents. Conclusion:The level of psychological resilience of adolescents in Minhang District of Shanghai is above the medium level, and family functioning has a significant impact on their mental toughness.
6.Meta-analysis of Kirschner's needle and elastic intramedullary nail fixation for the treatment of proximal humeral fractures in children.
Tao SHI ; Zi-Hang XU ; Xin ZHANG ; Yu-Wang QIAN ; Lei ZHU ; Lai-Fa KONG
China Journal of Orthopaedics and Traumatology 2025;38(6):633-640
OBJECTIVE:
To systematically evaluated clinical efficacy of Kirschner's needle and elastic intramedullary nail fixation in treating proximal humeral fractures in children by Meta-analysis.
METHODS:
Literature on the treatment of proximal humeral fractures in children with Kirschler needles and elastic intramedullary nails published on Wanfang, VIP, CNKI and China biology medicine (CBM), PubMed, Embase, and Web of Science databases were searched from the establishment of databases to October, 2023. Literature extraction, management and data entry were performed by Endnote X9 and Excel 2019, and Meta-analysis was conducted by RevMan 5.3 software. The operation time, hospital stay, fracture healing time, shoulder joint extension range of motion, disabilities of arm, shoulder and hand(DASH) questionnaire score, Neer score or Constant-Murley score and complications were compared between two groups.
RESULTS:
A total of 7 literatures were included, 1 was prospective study, 6 were retrospective cohort study. There were 521 children, 264 children in Kirschner wire group and 257 children in elastic intramedullary nail fixation group. The results of Meta analysis showed operation time[WMD=-12.61, 95%CI(-24.89, -0.33), P=0.04], fracture healing time[WMD=-0.26, 95%CI(-0.49, -0.02), P=0.03], total complication rate [OR=6.83, 95%CI(3.33, 14.01), P<0.001], nail tract infection rate[OR=6.77, 95%CI(1.72, 26.69), P=0.006] and displacement fracture rate[OR=3.57, 95%CI(1.35, 9.44), P=0.01] between two groups had statistically differences(P>0.05), while there were no statistically significant difference in comparison of hospital stay, shoulder joint extension range of motion, DASH, Neer score, Constant-Murley score, and incidence of skin irritation between two groups (P>0.05).
CONCLUSION
Kirschner's needle internal fixation has a short operation time and simple operation, but it has a higher incidence of complications compared with elastic nail internal fixation technique. In terms of efficacy and safety, elastic intramedullary nail fixation is one of the options for the treatment of proximal humeral fractures in children.
Humans
;
Fracture Fixation, Intramedullary/instrumentation*
;
Child
;
Shoulder Fractures/physiopathology*
;
Bone Nails
;
Bone Wires
;
Male
;
Needles
;
Female
7.Expert consensus on pulpotomy in the management of mature permanent teeth with pulpitis.
Lu ZHANG ; Chen LIN ; Zhuo CHEN ; Lin YUE ; Qing YU ; Benxiang HOU ; Junqi LING ; Jingping LIANG ; Xi WEI ; Wenxia CHEN ; Lihong QIU ; Jiyao LI ; Yumei NIU ; Zhengmei LIN ; Lei CHENG ; Wenxi HE ; Xiaoyan WANG ; Dingming HUANG ; Zhengwei HUANG ; Weidong NIU ; Qi ZHANG ; Chen ZHANG ; Deqin YANG ; Jinhua YU ; Jin ZHAO ; Yihuai PAN ; Jingzhi MA ; Shuli DENG ; Xiaoli XIE ; Xiuping MENG ; Jian YANG ; Xuedong ZHOU ; Zhi CHEN
International Journal of Oral Science 2025;17(1):4-4
Pulpotomy, which belongs to vital pulp therapy, has become a strategy for managing pulpitis in recent decades. This minimally invasive treatment reflects the recognition of preserving healthy dental pulp and optimizing long-term patient-centered outcomes. Pulpotomy is categorized into partial pulpotomy (PP), the removal of a partial segment of the coronal pulp tissue, and full pulpotomy (FP), the removal of whole coronal pulp, which is followed by applying the biomaterials onto the remaining pulp tissue and ultimately restoring the tooth. Procedural decisions for the amount of pulp tissue removal or retention depend on the diagnostic of pulp vitality, the overall treatment plan, the patient's general health status, and pulp inflammation reassessment during operation. This statement represents the consensus of an expert committee convened by the Society of Cariology and Endodontics, Chinese Stomatological Association. It addresses the current evidence to support the application of pulpotomy as a potential alternative to root canal treatment (RCT) on mature permanent teeth with pulpitis from a biological basis, the development of capping biomaterial, and the diagnostic considerations to evidence-based medicine. This expert statement intends to provide a clinical protocol of pulpotomy, which facilitates practitioners in choosing the optimal procedure and increasing their confidence in this rapidly evolving field.
Humans
;
Calcium Compounds/therapeutic use*
;
Consensus
;
Dental Pulp
;
Dentition, Permanent
;
Oxides/therapeutic use*
;
Pulpitis/therapy*
;
Pulpotomy/standards*
8.Expert consensus on management of instrument separation in root canal therapy.
Yi FAN ; Yuan GAO ; Xiangzhu WANG ; Bing FAN ; Zhi CHEN ; Qing YU ; Ming XUE ; Xiaoyan WANG ; Zhengwei HUANG ; Deqin YANG ; Zhengmei LIN ; Yihuai PAN ; Jin ZHAO ; Jinhua YU ; Zhuo CHEN ; Sijing XIE ; He YUAN ; Kehua QUE ; Shuang PAN ; Xiaojing HUANG ; Jun LUO ; Xiuping MENG ; Jin ZHANG ; Yi DU ; Lei ZHANG ; Hong LI ; Wenxia CHEN ; Jiayuan WU ; Xin XU ; Jing ZOU ; Jiyao LI ; Dingming HUANG ; Lei CHENG ; Tiemei WANG ; Benxiang HOU ; Xuedong ZHOU
International Journal of Oral Science 2025;17(1):46-46
Instrument separation is a critical complication during root canal therapy, impacting treatment success and long-term tooth preservation. The etiology of instrument separation is multifactorial, involving the intricate anatomy of the root canal system, instrument-related factors, and instrumentation techniques. Instrument separation can hinder thorough cleaning, shaping, and obturation of the root canal, posing challenges to successful treatment outcomes. Although retrieval of separated instrument is often feasible, it carries risks including perforation, excessive removal of tooth structure and root fractures. Effective management of separated instruments requires a comprehensive understanding of the contributing factors, meticulous preoperative assessment, and precise evaluation of the retrieval difficulty. The application of appropriate retrieval techniques is essential to minimize complications and optimize clinical outcomes. The current manuscript provides a framework for understanding the causes, risk factors, and clinical management principles of instrument separation. By integrating effective strategies, endodontists can enhance decision-making, improve endodontic treatment success and ensure the preservation of natural dentition.
Humans
;
Root Canal Therapy/adverse effects*
;
Consensus
;
Root Canal Preparation/adverse effects*
9.Study on the quality standard and application of polyoxyl(15)hydroxystearate
Jinhua CHEN ; Mingqing CHEN ; Zhengyu LIU ; Chunmeng SUN ; Lei JIANG ; Jiasheng TU
Drug Standards of China 2025;26(2):135-144
Objective:To study and establish the quality standard of Polyoxyl 15 hydroxystearate(HS15),a phar-maceutical excipient,and systematically evaluate its functionality-related characteristics and safety.HS15 was applied to the preparation of docetaxel(DTX)injection to further investigate the safety and pharmacokinetic char-acteristics of the injection in vitro and in vivo.Methods:Based on the general USP-NF2024,EP11.0 and the fourth general rules of the Chinese Pharmacopoeia 2020 edition,the quality standards of HS15 were studied.Combined with the functional properties of surfactants,the critical micelle concentration of HS15 was investigated,and its safety was investigated by hemolysis test and vascular irritation test in vitro.HS15 was further applied to the preparation of DTX injection,and the safety and efficacy of the preparation were comprehensively evaluated by in vitro cytotoxicity test and in vivo pharmacokinetic study.Results:According to the experimental results and the pharmacopoeia of various countries,the quality standard of HS15 was preliminarily formulated.When the concen-tration of HS15 was 1 mg·mL-1,the hemolysis rate was about0.2%,the vascular irritation was small,and the DTX injection was safe in vitro and in vivo.The pharmacokinetic behavior was in line with expectations.Conclusion:This study successfully established the quality standard of HS15,and its functional correlation index research and safety evaluation strategy can provide reference for the quality control of similar excipients.The appli-cation of HS15 in the preparation of DTX injection provides a theoretical and experimental basis for its application in the development of insoluble antitumor drug injection.
10.Effect of TWIK-1 channel on hypokalemia-induced abnormal pacemaker activities in human cardiomyocytes and its mechanisms
Hengxi ZHANG ; Lei XIONG ; Yue WU ; Jinhua LV ; Zheng ZUO ; Ruolan LI ; Dechou ZHANG ; Ping LIU ; Dongchuan ZUO
Chinese Journal of Pathophysiology 2025;41(5):895-901
AIM:This study aims to investigate the impact of TWIK-1 channels on abnormal pacemaker activi-ties induced by hypokalemia and to elucidate the underlying mechanisms.METHODS:The gene sequences encoding hu-man TWIK-1,specific TWIK-1 shRNA and TWIK-1-T118i mutant were synthesized and subsequently subcloned into lenti-viral vectors.To knock down the TWIK-1 gene in human induced pluripotent stem cell-derived cardiomyocytes(hiPSC-CMs),the cells were transduced with lentivirus carrying the specific TWIK-1 shRNA sequences.For the overexpression of TWIK-1 or the TWIK-1-T118i mutant in HL-1 mouse cardiomyocytes,the cells received lentiviral transduction containing the respective gene sequences.Patch-clamp techniques were employed to assess the effects of 1 mmol/L extracellular K+on the membrane potentials and whole-cell currents of the cardiomyocytes.RESULTS:Under conditions of 1 mmol/L extra-cellular K+,depolarization of membrane potentials was observed in the hiPSC-CMs and the HL-1 mouse cardiomyocytes ex-pressing human TWIK-1 channel,leading to the induction of abnormal pacemaker activities.This phenomenon could be reversibly abolished by the removal of extracellular Na+or inhibited through TWIK-1 knockdown.In contrast,the mem-brane potentials of HL-1 mouse cardiomyocytes expressing human TWIK-1-T118i mutant hyperpolarized,with no occur-rence of abnormal pacemaker activities.The hiPSC-CMs exhibiting abnormal pacemaker activities at 1 mmol/L extracellu-lar K+demonstrated TWIK-1-like Na+leak currents,which were blocked by quinine,a non-selective blocker of TWIK-1.CONCLUSION:The TWIK-1 channels play a critical role in the development of hypokalemia-induced abnormal pace-maker activities in human cardiomyocytes by facilitating Na+leak currents.

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