Objective To evaluate the efficacy of Gateway balloon dilation in the treatment of symptomatic severe stenosis of middle cerebral artery.Methods The clinical data and imaging materials of 98 patients with severe symptomatic stenosis of the middle cerebral artery,who were admitted to the Second Affiliated Hospital of Nanchang University of China from May 2019 to August 2022 to receive Gateway balloon dilation,were retrospectively analyzed.The diameter of the narrowed artery before and after Gateway balloon dilation treatment,peak systolic blood flow velocity(PSV),end-diastolic blood flow velocity(EDV),Mori classification of stenosis lesion,operation-related complications,imaging manifestations and clinical follow-up results were analyzed.Results Of the 98 patients,Mori type A was seen in 83(84.69％)and Mori type Bin 15(15.31％).Successful Gateway balloon dilation procedure was accomplished in all patients.After surgery,the symptoms were improved or stabilized to varying degrees.The mean residual lumen diameter of the stenosis lesion was significantly increased from preoperative(2.01±0.13)mm to postoperative(2.33±0.25)mm,the stenosis ratio was remarkably decreased from preoperative(81.28±15.17)％to postoperative(50.24±12.83)％,the PSV and EDV were strikingly decreased from preoperative(251.01±60.13)cm/s and(104.28±32.25)cm/s to postoperative(155.33±53.28)cm/s and(70.24±36.33)cm/s respectively,the differences were statistically significant(all P＜0.05).Seven patients developed surgical complications,which were improved in short time.The patients were followed up for 10 months,modified Rankin Scale(mRS)score of ≤2 points was obtained in 88 patients(89.79％),indicating that the patients had a good quality of life as well as a good functional recovery.Conclusion For the treatment of symptomatic severe stenosis of middle cerebral artery,Gateway balloon dilation carries a significant long-term therapeutic effect with fewer surgical complications.Therefore,Gateway balloon dilation is an effective treatment for this type of disease.

A novel RNA virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is responsible for the ongoing outbreak of coronavirus disease 2019 (COVID-19). Population genetic analysis could be useful for investigating the origin and evolutionary dynamics of COVID-19. However, due to extensive sampling bias and existence of infection clusters during the epidemic spread, direct applications of existing approaches can lead to biased parameter estima-tions and data misinterpretation. In this study, we first present robust estimator for the time to the most recent common ancestor (TMRCA) and the mutation rate, and then apply the approach to analyze 12,909 genomic sequences of SARS-CoV-2. The mutation rate is inferred to be 8.69 × 10-4 per site per year with a 95％ confidence interval (CI) of [8.61 × 10-4, 8.77 × 10-4], and the TMRCA of the samples inferred to be Nov 28, 2019 with a 95％ CI of [Oct 20, 2019, Dec 9, 2019]. The results indicate that COVID-19 might originate earlier than and outside of Wuhan Seafood Market. We further demonstrate that genetic polymorphism patterns, including the enrichment of specific haplotypes and the temporal allele frequency trajectories generated from infection clusters, are similar to those caused by evolutionary forces such as natural selection. Our results show that population genetic methods need to be developed to efficiently detangle the effects of sampling bias and infection clusters to gain insights into the evolutionary mechanism ofSARS-CoV-2. Software for implementing VirusMuT can be downloaded at https://bigd.big.ac.cn/biocode/tools/BT007081.