Objective:To evaluate the effect of coronary microvascular dysfunction (CMD) on left atrial and ventricular function in patients with ischemia and non-obstructive coronary artery disease (INOCA) under the drug stress of regadenoson by speckle tracking imaging and left ventricular pressure-strain ring ultrasound technology.Methods:A total of 43 patients with INOCA who were admitted to the Department of Cardiology of the First Bethune Hospital of Jilin University from May 2022 to October 2023 were prospectively enrolled, and drug stress tests were performed. The coronary flow velocity reserve (CFVR) values were obtained by transthoracic Doppler echocardiography, and the INOCA patients with CFVR<2.0 were assigned to the CMD group ( n=24), and those with CFVR≥2.0 were assigned to the contrast group (CON group, n=19), and 20 healthy people without chest pain matched by clinical data were selected as the negative group (NEG group). The differences in general clinical data, routine echocardiography before and after stress, left atrial strain, and myocardial work parameters were compared between the groups. The correlation analysis of intra-group parameters was performed, and then the ROC curve was used to evaluate the diagnostic value of ultrasound parameters for INOCA. Results:Compared with the CON group and the NEG group, the ratio of early diastoic velocity E peak of mitral value orifice to the late diastoic velocity A peak(E/A) decreased and the ratio of early diastoic velocity E peak of mitral valve orifice to the early diastoic velocity e′ of the mitral valve annulus(E/e′) increased in the CMD group, and the differences were statistically signnificant (all P<0.05).There were statistically significant differences in left atrial strain parameters including left atrial strain reservoir (LASr), left atrial conduit strain (LAScd), left atrial contraction strain (LASct) between CON group and CMD group before and after stress (all P<0.05).However, there were no statistically significant differences between CON group and CMD group in myocardial work parameters including global longitudinal strain (GLS), peak strain dispersion (PSD), global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE) at rest (all P>0.05), and there were significant differences only after stress (all P<0.05). E/e′ was negatively correlated with LASr and LAScd in the CMD group and CON group ( rs=-0.36, r=-0.31; all P<0.05), GLS was positively correlated with GWI, GCW, GWE( r=0.81, 0.61, 0.37; all P<0.05). GLS was positively correlated with GWI, GCW and GWE at stress state( r=0.66, 0.51, 0.52; all P<0.05), and negatively correlated with GWW ( rs=-0.39, P<0.05). PSD was positively correlated with GWW ( rs=0.30, P<0.05), and negatively correlated with GWI, GCW and GWE ( r=-0.46, -0.40, -0.38; all P<0.05). Univariate regression analysis showed that left atrial strain and myocardial work had good predictive values for CMD, and the predictive values of rest LASr and stress GLS were higher, with AUC values of 0.927 and 0.882, respectively. Conclusions:In patients with INOCA and CMD, the left atrial strain capacity decreases at both rest and stress state, and the myocardial work capacity decreases only under the stress. The changes in parameters of left atrial strain and myocardial work provide new ultrasound parameters and predictors for clinical evaluation of CMD.

Objective:To determine the evaluation indexes of national standard strains of genotypes 1, 3 and 5 of Japanese encephalitis virus (JEV) and evaluate the national standard JEV strains.Methods:According to the national standard strain evaluation technical standards of pathogenic microbial bacteria (virus) species, based on the application of Japanese encephalitis virus research, and according to the morphological characteristics, biological characteristics, molecular biological characteristics and other research data to identify the characteristics of G1, G3 and G5 genotypes of JEV.Results:Spherical virus particles with a diameter of about 60 nm were visible under electron microscope of the three Japanese encephalitis virus strains. The cytopathic effect was mainly characterized by cell shrinkage and exfoliation in BHK-21 and Vero cell lines, cell fusion and exfoliation were shown after infection with C6/36 cell line; the virus titer was 10 5-10 7 PFU/ml, and the plaque size was different by genotype. The median lethal dose of intrabitoneal challenge in G1, G3 and G5 JEV in three weeks-old mice was 50.51 PFU, 6.98 PFU, and 8.13 PFU, and the median lethal dose of intracranial challenge in five weeks mice was 3 PFU, 0.3 PFU, 1.35 PFU. The whole genome length of G1, G3 and G5 JEV was 10 967 bp, 10 976 bp and 10 983 bp, respectively. Conclusions:Three genotypic national standard strains of JE V were identified and evaluated by electron microscopy, cell, animal and genome laboratory indexes, which provided reference for the identification and evaluation of other national standard strains of JEV.

ObjectiveTo divide the muscle into different subzones according to different density ranges using the stratified analysis on the basis of myosteatosis， and to investigate the effect of muscle density changes on complications （Clavien-Dindo grade ≥Ⅲ） after orthotopic liver transplantation （OLT）. MethodsA retrospective analysis was performed for the medical records of 145 patients who underwent OLT in The First Hospital of Jilin University from May 2013 to September 2020， and with the plain CT scan images of the largest level of lumbar 3 vertebrae of each patient as the original data， Neusoft Fatanalysis software was used to measure related muscle parameters. The independent-samples t test was used for comparison of normally distributed continuous data between two groups， and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups. The chi-square test or Fisher test was for comparison of categorical data between two groups. RIAS software was used to extract clinical features and perform analysis and modeling， and three machine learning models of logistic regression （LR）， support vector machine （SVM）， and random forest （RFC） were constructed. The receiver operating characteristic （ROC） curve， the calibration curve， and the decision curve were plotted for each model to calculate the area under the ROC curve （AUC）， sensitivity， specificity， precision， F1 score， and accuracy. ResultsThe three machine learning models of LR-C， SVM-C， and RFC-C were established based on the 7 clinical features before muscle stratification analysis， among which the RFC-C model had an AUC of 0.803， a sensitivity of 0.588， and a specificity of 0.778 in the test set. Among the models of LR-CS， SVM-CS， and RFC-CS established based on the 16 clinical features after muscle stratification analysis， the LR-CS and SVM-CS models had an AUC of 0.852 in the test set， with a sensitivity of 0.765 and 0.706， respectively， and a specificity of 0.889 and 0.926， respectively. Comparison of the AUC， sensitivity， specificity， precision， F1 score， and accuracy of each model in the test set before and after muscle stratification analysis showed that there were improvements in the parameters of the predictive model after muscle stratification analysis. Comparison of the decision curves and calibration curves of each predictive model showed that the LR-CS and SVM-CS models had good efficacy in predicting postoperative complications （Clavien-Dindo grade≥Ⅲ） in OLT patients. ConclusionOn the basis of myosteatosis， the division of the muscle into different subzones according to different densities using the stratified analysis has a certain value in predicting postoperative complications in patients with OLT.