To comprehend the genetic evolutionary characteristics and biological properties of the H4N1 subtype avian influenza virus(AIV)in China,this study conducted whole genome sequen-cing,genetic evolutionary analysis,and pathogenicity test in BALB/c mice of a duck-derived H4N1 subtype AIV strain(DK/GX/E1424/20)isolated from the live poultry market in the southern re-gion in 2020.The results indicated that the cleavage site motif of the HA protein was PEKASR/GLF,which conformed to the characteristics of low pathogenic AIV.All the eight gene fragments were situated in the Eurasian lineage,and the homology of AIV-related genes of the H1N1,H3N8,H4N6,H6N1,and H10N8 subtypes isolated from wild waterfowl was the highest,representing a recombinant virus strain.Without prior adaptation,it replicated effectively in the lungs and turbi-nates of mice,with viral titers of 3.00 and 2.08 log10EID50/mL respectively,and induced weight loss in infected mice.This study suggested that this virus had significant genetic diversity and low pathogenicity in mice,posing a potential risk for mammalian infection.

To comprehend the genetic evolutionary characteristics and biological properties of the H4N1 subtype avian influenza virus(AIV)in China,this study conducted whole genome sequen-cing,genetic evolutionary analysis,and pathogenicity test in BALB/c mice of a duck-derived H4N1 subtype AIV strain(DK/GX/E1424/20)isolated from the live poultry market in the southern re-gion in 2020.The results indicated that the cleavage site motif of the HA protein was PEKASR/GLF,which conformed to the characteristics of low pathogenic AIV.All the eight gene fragments were situated in the Eurasian lineage,and the homology of AIV-related genes of the H1N1,H3N8,H4N6,H6N1,and H10N8 subtypes isolated from wild waterfowl was the highest,representing a recombinant virus strain.Without prior adaptation,it replicated effectively in the lungs and turbi-nates of mice,with viral titers of 3.00 and 2.08 log10EID50/mL respectively,and induced weight loss in infected mice.This study suggested that this virus had significant genetic diversity and low pathogenicity in mice,posing a potential risk for mammalian infection.

Objective Taking the Digestive Medical Coordinated Development Center of Beijing Municipal Administration of Hospitals (hereinafter referred to as the "Digestive Medical Coordinated Development Center") as an example ,this paper aims to ex-plore the idea of building a collaborative development system of medical disciplines dominated by advantageous disciplines .Methods Summarizing the construction experience of the Digestive Medical Coordinated Development Center to illustrate the significance ,identify existed challenges and construction pathways of the center .Results The Digestive Medical Coordinated Development Center has built a series of public service platforms for its member institutions ,and improved the system and incentive mechanism to gather the develop-ment synergy of the center .Conclusions Based on the advantages of the collectivized management of Beijing Municipal Administration of Hospital ,the Digestive Medical Coordinated Development Center advances synchronously in the dimensions of scientific research , medical treatment ,information construction and talent ,as well as formed its own development characteristics and accumulated valuable experience for the construction of discipline collaboration center of municipal hospitals .

Objective:To analysis the correlation of Wnt/β-catenin signaling pathway,OPN and MMP-13 in rabbit model with different degree of osteoarthritis (OA).Methods:Forty New Zealand white rabbits were randomly divided into four groups of 10 each,then we constructed the rabbit model with different degree of osteoarthritis (OA) by different concentrations of papain.The mRNA and protein levels of β-catenin,OPN,MMP-13,type Ⅱ collagen and proteoglycan were detected by Real-Time PCR and ELISA,respectively.Results:We have successfully established OA rabbit model by different concentrations of papain,and these OA rabbits model could be divided into mild,moderate and severe three level by Mankin scoring system,chondrocytes.Compared with the normal control group,the protein levels of β-catenin,OPN,and MMP-13 in the osteoarthritis were significantly increased,while the protein levels of type Ⅱ collagen and proteoglycan were significantly decreased (P＜0.05).With the increasing severity of OA,the results were consistent (P＜0.05).Conclusions:These results indicated that Wnt/β-catenin signaling pathway might regulate the expression of OPN,thereby affecting the expression of MMP-13,and ultimately have an impact on the occurrence ofosteoarthritis.

Objective To detect the normal values of fetal cerebellar vermis using transabdominal ultrasonography and assess its clinical significance in the diagnosis of vermal hypoplasia(agenesis). Methods A total of 111 fetuses were evaluated by transabdominal sonography between 20 and 40 weeks of gestation.The mid-sagittal antero-posterior(AP) and cranio-caudal(CC) vermian diameters were measured. A second group of 15 fetuses with cisterns magna were assessed and compared with the value of normal fetuses.0.05) and correlated linearly with gestational age ( AP = - 5.406 + 0. 761 GA, r = 0.97 ; CC = - 5.795 +fissure, second fissure and fastigium may help identify developmental anomalies. Conclusions Transabdominal ultrasonography is a valuable tool in the study of fetal vermis during the second half of pregnancy.