After sequencing, we amplified and cloned foot-and-mouth disease virus (FMDV) O/QYYS/s/06 whole genome by three fragments. These three fragments were cloned into vector P43 one by one to construct recombinant plasmid P43C, which carried the full-length cDNA of FMDV O/QYYS/s/06. Then, plasmid P43C and plasmid T7 expressing T7 RNA polymerase were co-transfected into BHK-21 cells. After 48 h, we harvested the culture broth from transfected BHK-21 cells and inoculated into 2-3 day-old sucking mice. After four generation passage, the virus harvested from sucking mice was confirmed to be type O FMDV by the indirect hemagglutination test, sucking mice's neutralization test and sequencing. The results showed that we have successfully constructed the full-length cDNA clone of FMDV O/QYYS/s/06 strain.
Animals ; Animals, Newborn ; Cloning, Molecular ; DNA, Complementary ; genetics ; DNA, Viral ; biosynthesis ; genetics ; Foot-and-Mouth Disease ; virology ; Foot-and-Mouth Disease Virus ; classification ; genetics ; pathogenicity ; Mice ; Transcription, Genetic ; Transfection

Objective:To evaluate the visibility of deep medullary veins (DMVs) in patients with recent subcortical small infarction (RSSI), and explore the influence of DMVs visibility in RSSI with cognitive impairment.Methods:One hundred and sixty-four first-onset RSSI patients admitted to Department of Neurology, Third Affiliated Hospital of Nanjing Medical University from February 2023 to May 2024 were selected. According to Montreal cognitive assessment (MoCA), they were divided into normal cognitive function group (MoCA scores≥26, n=78) and cognitive impairment group (MoCA scores<26, n=86); DMVs visibility on amplitude map or minimum intensity projection map in susceptibility weighted imaging was evaluated by visual scoring method. Univariate analysis was used to compare the differences in general clinical data and DMVs visibility scores between two groups; multivariate Logistic regression analysis was used to identify the independent influencing factors for RSSI combined with cognitive impairment. Spearman rank correlation was used to analyze the correlations of DMVs visibility score with MoCA score and cognitive scores in various cognitive domains, while mediation analysis was used to explore the correlations of MoCA score with total white matter hyperintensity (WMH) volume and DMVs visibility score. Results:The DMVs visibility score, age, hypertension proportion, periventricular white matter hyperintensity (PWMH) volume, and total WMH volume in RSSI patients with cognitive impairment were significantly higher, while body mass index (BMI) was statistically lower than those in patients with normal cognitive function ( P<0.05). Multivariate Logistic regression analysis showed that age ( OR=1.069, 95% CI: 1.017-1.123, P=0.008), total WMH volume ( OR=1.845, 95% CI: 1.050-3.241, P=0.033), and DMVs visibility score ( OR=1.239, 95% CI: 1.057-1.454, P=0.008) were independent influencing factors for cognitive impairment in RSSI patients. Spearman rank correlation showed negative correlations between DMVs visibility score and MoCA score ( rs=-0.472, P<0.001), between DMVs visibility score and score of executive function and visual-spatial skills ( rs=-0.329, P<0.001), between DMVs visibility score and attention score ( rs=-0.491, P<0.001), between DMVs visibility score and delayed recall score ( rs=-0.516, P<0.001), and between DMVs visibility score and directional ability score ( rs=-0.162, P=0.039) in RSSI patients. Mediation analysis results showed that DMVs visibility score not only had a direct effect of 87.5% on MoCA score, but also had an indirect effect of 12.5% on MoCA score through total WMH volume. Conclusion:Cognitive impairment trend to appear in RSSI patients with high DMVs visibility score, and WMH volume plays a mediating role in the effect of DMVs visibility on RSSI with cognitive impairment.

Quantitative susceptibility mapping (QSM) is a noninvasive MR post-processing technique that can quantitatively analyze tissue magnetic susceptibility, which has important value in early diagnosis and assessment of cerebral small vessel disease (CSVD). In recent years, QSM has gradually been applied in clinical neuroimaging both domestically and internationally, becoming a new hotspot. This review focuses on the principle and classification of QSM, application of QSM in the gray matter microstructure, white matter microstructure, venous oxygen saturation assessment, cerebral microhemorrhage and cognitive function assessment of CSVD, so as to provide new perspective for its neuroimaging evaluation.