OBJECTIVE To explore the change of adaptive cost of Klebsiella pneumoniae in subinhibitory concen-tration of Epigallocatechin gallate(EGCG)for subculture of 14 days so as to provide experimental support for clinical transformation of EGCG.METHODS The drug resistance genes in the K.pneumoniae strains were ana-lyzed by whole genome sequencing technology.The change of biofilm formation ability was detected by crystal vio-let staining,the transcriptional levels of quorum sensing gene luxS and its regulatory genes(lsrK and lsrR)as well as virulence genes(aerobactin and rmpA)were detected by means of fluorescent quantitative polymerase chain reaction(PCR).The pathogenicity of the K.pneumoniae was tested through survival assay of greater wax moth.RESULTS The whole genome sequencing showed that 1 strain of non-mucous CRKP and 2 strains of mucous CRKP were ST11,all of which carried bla KPC-2 gene.There was no change in the growth curve of sub-culture after treatment with subinhibitory concentration of EGCG;the biofilm forming ability was reduced.The expression level of luxS gene was higher in the non-treatment group.The transcriptional level of ionophore aer-obactin was inhibited with the increase of subculture days and subinhibitory concentration;the transcription ability of the virulence gene mucous phenotype regulatory gene rmpA was inhibited as well.The survival rate of greater wax moth increased,and there was significant difference(P＜0.05).CONCLUSIONS The growth rate of K.pneumoniae strains dose not change after the treatment with the subinhibitory concentration of EGCG.The bio-film formation and the transcriptional levels of virulence genes and quorum sensing genes as well as the pathoge-nicity are inhibited,which may provide experimental bases for clinical application of EGCG.

OBJECTIVE To explore the change of adaptive cost of Klebsiella pneumoniae in subinhibitory concen-tration of Epigallocatechin gallate(EGCG)for subculture of 14 days so as to provide experimental support for clinical transformation of EGCG.METHODS The drug resistance genes in the K.pneumoniae strains were ana-lyzed by whole genome sequencing technology.The change of biofilm formation ability was detected by crystal vio-let staining,the transcriptional levels of quorum sensing gene luxS and its regulatory genes(lsrK and lsrR)as well as virulence genes(aerobactin and rmpA)were detected by means of fluorescent quantitative polymerase chain reaction(PCR).The pathogenicity of the K.pneumoniae was tested through survival assay of greater wax moth.RESULTS The whole genome sequencing showed that 1 strain of non-mucous CRKP and 2 strains of mucous CRKP were ST11,all of which carried bla KPC-2 gene.There was no change in the growth curve of sub-culture after treatment with subinhibitory concentration of EGCG;the biofilm forming ability was reduced.The expression level of luxS gene was higher in the non-treatment group.The transcriptional level of ionophore aer-obactin was inhibited with the increase of subculture days and subinhibitory concentration;the transcription ability of the virulence gene mucous phenotype regulatory gene rmpA was inhibited as well.The survival rate of greater wax moth increased,and there was significant difference(P＜0.05).CONCLUSIONS The growth rate of K.pneumoniae strains dose not change after the treatment with the subinhibitory concentration of EGCG.The bio-film formation and the transcriptional levels of virulence genes and quorum sensing genes as well as the pathoge-nicity are inhibited,which may provide experimental bases for clinical application of EGCG.

Objectives:This study aims to explore the effects of pioglitazone on the attenuation of ventricular arrhythmias(VAs)induced by β1-adrenergic receptor autoantibodies(β1AAb)and its potential mechanisms. Methods:48 SD rats were uniformly randomly divided into four groups using number table:control group received vehicle injection,β1AAb group received back multi-point injection of β1AR-ECLⅡ antigen peptide with adjuvant,2 mg/(kg·time),pioglitazone group received pioglitazone gavage for 2 weeks after 8 weeks of immunization,4 mg/(kg·d),and GW9662 group received pioglitazone+GW9662 intraperitoneal injection for 2 weeks after 8 weeks of immunization,1 mg/(kg·d).Powerlab recorded electrocardiograms and blood collection every 2 weeks.Baseline and week 10 echocardiography were recorded,followed by electrophysiology,histopathology,immunohistochemical staining,and electron microscopy examination after 10 weeks. Results:Compared to control group,β1AAb group showed a higher incidence of ventricular arrhythmias,shorter ventricular effective refractory period(VERP),longer action-recovery interval(ARI),lower left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(LVFS),lower positive staining area ratio of glucose transporter 1(GLUT1)and carnitine palmitoyltransferase 1a(CPT1a),all P＜0.05.Mitochondrial morphology abnormalities and network damage were also significantly observed(P＜0.05).In contrast to β1AAb group,pioglitazone group showed a reduced incidence of ventricular arrhythmias,prolonged VERP,shortened ARI,recovered LVEF and LVFS,increased the positive staining area ratio of GLUT1 and CPT1a,all P＜0.05.Improvement was observed in mitochondrial morphology abnormalities and network damage(P＜0.05).Compared to pioglitazone group,GW9662 group exhibited a higher incidence of ventricular arrhythmias,shorter VERP,and longer ARI,lower LVEF and LVFS,lower positive staining area ratio of GLUT1 and CPT1a,all P＜0.05.Mitochondrial morphology abnormalities and network damage did not recover(P＜0.05). Conclusions:Pioglitazone can reduce VAs induced by β1AAb,improve ventricular electrical conduction and activation recovery time heterogeneity,and mitigate ventricular remodeling caused by β1AAb at the tissue pathology level,accompanied by upregulation of ventricular cardiomyocyte glucose and lipid transport channel proteins and repair of damaged mitochondrial networks.

Objective:To investigate the relationship between indicators of carotid atherosclerosis and onset of ischemic stroke in patients with non-valvular atrial fibrillation (NVAF).Methods:This is a case-control study, a total of 397 NVAF patients with newly diagnosed ischemic stroke (case group) and 3 038 NVAF patients without ischemic stroke (control group) from January 2015 to December 2017 were included in the study. Differences in general clinical features and carotid atherosclerosis indexes between the two groups were compared. Univariate and multivariate logistic regressions were used to analyze the correlation between carotid atherosclerosis indexes and ischemic stroke.Results:Proportions of patients with carotid intima thickening, carotid plaque, stable plaque, unstable plaque, and moderate to severe stenosis were higher in the ischemic stroke group than those in the control group (82.1% vs. 64.4%, 69.3% vs. 50.3%, 43.6% vs. 30.6%, 25.7% vs. 19.7%, and 7.3% vs. 4.0%, respectively, all P <0.05). After adjustment of age, gender, heart failure, hypertension, low density lipoprotein -cholesterol and drug use, multivariate analyses showed that subjects with carotid intima thickening, carotid plaque, stable plaque, unstable plaque, moderate to severe stenosis had 1.766, 2.111, 1.892, 2.256 and 1.824 times the risk for the development of ischemic stroke compared with the subjects without any carotid atherosclerosis indicators. Conclusion:Carotid atherosclerosis, especially with unstable carotid plaque, is associated with ischemic stroke in patients with NVAF.